PATENT ABSTRACT
The present invention is directed to methods and apparatus for tempering the temperature of a liquid in a fluid conducting system. More particularly, some embodiments of the invention relates to tempering the temperature of water supplied to a fixture from a water heater in a fluid conducting system. The system can include a heater for heating the fluid and a diffuser for slowing the rate at which water provided to a decontamination fixture is heated.

PATENT DESCRIPTION
[0001]    This application claims priority to U.S. Provisional Application No. 60/592,710, filed Jul. 30, 2004, herein incorporated by reference in its entirety. 
     
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
       [0002]    The present invention concerns a method and apparatus for tempering the temperature of a liquid in a fluid conducting system. More particularly, the invention relates to tempering the temperature of water supplied to a fixture from a water heater in a fluid conducting system. 
         [0003]    Thermally controlled or thermostatic mixing valves are well known. Valves of this type receive both hot and cold fluid, typically water, and allow the fluids to mix to an intermediate temperature. The temperature is controlled using a thermally responsive control member, such as a thermostat, to assist in maintaining the fluid temperature according to an established setting. 
         [0004]    One particular application of thermostatic mixing valves is in connection with emergency shower and eyewash systems. Toxic and hazardous chemicals are used in many environments, whether inside a factory building or outside at a remote construction site. The Occupational Safety and Health Act of 1970 was enacted to assure that workers would be provided with safe and healthful working conditions. Pursuant to this act, the Occupational Safety and Health Administration adopted regulations which require the availability of emergency eyewash and shower equipment for use as a form of first aid treatment. Emergency shower and eyewash systems have proliferated in a wide range of industries, including automotive, food processing, chemical processing, petroleum refining, steel production, pulp and paper, and waste water treatment. In each of these industries, workers may be exposed to chemicals that may cause serious tissue damage and destruction. These emergency shower and eyewash facilities are commonly associated with permanent structures and may be located inside or outside factory buildings with access to hot and cold water. 
         [0005]    In emergency fixture systems such as eyewash and emergency shower systems, even ground water of a moderate temperature (such as in the range of 50 degrees to 60 degrees F, as is common) is often perceived to be too cold, possibly discouraging sufficient duration of use of the emergency equipment. In addition, in northern climates, the ground water itself is sometimes barely above freezing, commonly near 35 degrees F. Under these circumstances, an emergency shower and eyewash system relying solely upon ground water often provides water that would be too cold to be endured for a sufficient period of time, even by a victim of a chemical accident. 
         [0006]    As a result, emergency shower and eyewash systems have been designed to provide tempered water by blending relatively hotter water with relatively colder water. A range of temperatures between 65 degrees F. to 95 degrees F. is comfortable to most persons. To provide tempered water within this range, most emergency fixture systems include a source of hot water, typically in the range of 140 degrees F. to 160 degrees F., that is mixed with ambient ground water. 
         [0007]    Many outdoor or other remote worksites such as construction sites may have the same or similar hazards that are associated with indoor worksites. Such remote worksites typically do not have a ready supply of hot water. Thus, workers at such sites exposed to chemicals or other irritants typically do not have access to emergency fixture systems that provide an adequate supply of tempered fluid, properly directed, for a sufficient period of time. Such workers may be required to resort to a ground-temperature water supply from a garden hose, a squirt bottle eye rinse apparatus, or other less suitable sources of fluid to rinse the exposed area(s). 
         [0008]    Emergency shower and eyewash systems must typically drench or rinse a user for at least 15 minutes. Thus, the source of tempered water should be able to provide the water for at least that length of time and to maintain the water within a comfortable temperature range for the user. In addition, the system should be able to maintain tempering of the water regardless of extreme fluctuations in the supply of hot or cold water to the thermostatic mixing valve. Often, a thermostatic mixing valve is used to maintain the water at an appropriately tempered temperature. 
         [0009]    The valve should respond accordingly to failures in the supply of hot or cold water to the valve, as well as failure of the valve itself. The valve should respond to these failures without placing the user of the emergency shower or eyewash system in greater peril than the user would be without the emergency system. For example, if the cold water supply fails and only hot water in the range of 140 degrees F. to 160 degrees F. is supplied, the user could suffer burns that may be more serious than the exposure being treated. Thus, it is desirable for the valve to prevent or minimize exposure to such hot water. 
         [0010]    Thermostatic mixing valves typically include a housing including hot and cold inlets, a mixed fluid outlet, a valve control assembly to adjust the amounts of hot and/or cold fluid permitted to flow through the valve, and a thermostat to control movement of the control assembly. The thermostat is typically positioned at least partially in the housing to sense the temperature of the mixture of fluid therein. The thermostat includes a material that is responsive to changes in the fluid temperature. For example, if the temperature increases, then movement of the thermostat causes movement of the control assembly, either increasing the flow of cold fluid, decreasing the flow of hot fluid, or both. 
         [0011]    Frequently, some fluid in the fluid circulation system of which the thermostatic mixing valve is a part has been stagnant for a period of time. During this stagnancy, the temperature of the hot fluid in the hot fluid supply line approaches ambient temperature, usually lower than the temperature of the hot fluid from the hot fluid supply. In a typical thermostatic mixing valve, when the temperature of the mixed fluid sensed by the thermostat is below the set point, the thermostat cooperates with the valve control assembly to increase the flow of hot fluid relative to the flow of cold fluid. 
         [0012]    In such a stagnant fluid circulation system, when a fixture (such as an eyewash station) is eventually actuated, the thermostat is often exposed to mixed water at a temperature below the set point temperature, even if the ratio of water from the hot and cold fluid supplies otherwise would be proportioned (if the hot fluid were at temperature) to produce mixed fluid at the desired temperature. Accordingly, responsive changes in the thermostat cause the valve control assembly to move to a position that increases the flow of hot fluid relative to the flow of cold fluid, thus increasing the mixed fluid temperature. As the valve continues to receive the supply of fluid from the hot fluid supply line that was formerly stagnant, the thermostat continues to cause the valve control assembly to move to a position that further increases flow from the hot fluid supply line and/or decreases the flow of cold fluid. If a sufficient volume of stagnant fluid is in the supply line between the hot fluid supply and the mixing valve, this process may continue until the thermostat has caused the valve assembly to move to a position wide-open to maximize the flow of fluid from the hot fluid source. 
         [0013]    Eventually, hot fluid from in the hot fluid supply (such as a water heater) progresses to the mixing valve. Because the valve control assembly is now wide-open to the hot fluid inlet, a large volume of hot fluid enters the valve housing through the hot fluid supply line that had previously been the source of the stagnant (and cooler) fluid. Once the hot fluid reaches the thermostat after mixing with whatever cold fluid is entering the valve, the thermostat responds to the temperature increase, causing the valve control assembly to move to reduce the flow of hot fluid and/or increase the flow of cold fluid. The length of time for the thermostat to respond as such and move the valve control assembly by a sufficient amount to reduce the temperature of mixed fluid below the set point can be long enough to permit a quantity of water above the set point temperature to flow from the valve. 
         [0014]    Thus, in one aspect of the invention, a decontamination apparatus is provided, comprising a fluid supply inlet configured for coupling to a fluid supply source, a first fluid line coupled to the fluid supply inlet and formed to include a first passageway in which a first fluid flows, and a heat exchange assembly configured to heat the first fluid in the first fluid line. The apparatus also comprises a mixing valve including a valve body formed to include a first fluid inlet to receive the first fluid from the first fluid line, a second fluid inlet to receive a second fluid from a second fluid line, and a mixed fluid outlet. A decontamination fixture is coupled to the mixed fluid outlet configured to discharge the mixed fluid. Optionally, a support interconnects at least the heat exchange assembly, the first fluid line, the mixing valve, and the decontamination fixture to permit movement of the apparatus as a unit. 
         [0015]    In one illustrative example according to this aspect of the invention, the support is a frame including frame members coupled together, a platform coupled to the frame, and wheels coupled to the frame to facilitate movement of the decontamination apparatus. 
         [0016]    In another illustrative example according to this aspect of the invention, the support includes a platform having a structure including a generally upwardly facing surface on which the heat exchange assembly, mixing valve, and decontamination fixture are supported, and a plurality of spaced apart support members coupled to and extending downwardly from the structure. 
         [0017]    Illustratively according to this aspect of the invention, the first and second fluid lines comprise fluid provided by the fluid supply source. 
         [0018]    Additionally illustratively according to this aspect of the invention the apparatus further comprises a junction in fluid communication with the fluid supply inlet, the junction splitting flow of fluid from the fluid supply source into the first fluid line and the second fluid line. 
         [0019]    Illustratively according to this aspect of the invention the second fluid line configured to be coupled to a second fluid supply source and formed to include a second passageway in which a second fluid stream flows. 
         [0020]    Illustratively according to this aspect of the invention the heat exchange assembly comprises a burner configured to combust fuel from a fuel source, and at least a portion of the first fluid passageway is proximate the burner so that when fuel from the fuel source is combusted at the burner, heat from the combustion is transferred into the first fluid in the first fluid passageway. 
         [0021]    Additionally illustratively according to this aspect of the invention, the burner is coupled to a controller, the decontamination fixture includes an actuator to actuate a valve controlling flow of fluid from the decontamination fixture, the burner igniting upon actuation of the decontamination fixture by a signal sent by the controller. 
         [0022]    Additionally illustratively according to this aspect of the invention the apparatus further comprises a fuel tank in which the fuel is stored, the fuel tank coupled to the frame to enable movement of the fuel tank upon movement of the frame. 
         [0023]    Illustratively according to this aspect of the invention the apparatus further comprises wheels coupled to the frame to facilitate movement of the decontamination apparatus. 
         [0024]    Additionally illustratively according to this aspect of the invention the apparatus further comprises a stand coupled to the frame to cooperate with the wheels to maintain decontamination apparatus in a position suitable for use by a user. 
         [0025]    Illustratively according to this aspect of the invention, the apparatus further comprises a means for dampening temperature change of the first fluid prior to entry into the first fluid inlet of the thermostatic mixing valve so that the mixing valve can adjust to a particular temperature increase over a given time period. 
         [0026]    Illustratively according to this aspect of the invention, the apparatus further comprises a diffuser coupled between the hot fluid line and the hot inlet to the mixing valve, the diffuser including a first fluid conduit and at least a second fluid conduit, a majority of the first fluid conduit being surrounded by the second fluid conduit, the first and second conduits being coupled together to cause fluid to flow into the first conduit, pass through a plurality of apertures formed in the first conduit, and into fluid outside the first conduit and in the second conduit. 
         [0027]    Illustratively according to this aspect of the invention, the decontamination fixture is an eyewash fixture including a basin and at least one nozzle directed at least partially upwardly. 
         [0028]    Illustratively according to this aspect of the invention, the decontamination fixture is a drench shower having fluid outlets directed at least partially downwardly. 
         [0029]    Illustratively according to this aspect of the invention, the decontamination fixture is a wand including a trigger configured to be actuated by a user and a spray nozzle to direct the flow of fluid from the wand depending on a direction selected by a user. 
         [0030]    According to another aspect of the invention, an apparatus for increasing the time period over which a temperature change occurs at a point in a fluid conducting system having fluid flowing therethrough comprises a first conduit having first and second ends and a plurality of openings provided between the first and second ends, a second conduit having first and second ends, the second conduit being coupled to the first conduit and at least partially surrounding at least a portion of the first conduit, wherein at least one of the openings is in the portion of the first conduit surrounded by the second conduit, one of the second conduit and the first conduit including a fluid inlet, and the other of the second conduit and the first conduit including a fluid outlet, wherein the first and second conduits are arranged to permit fluid to flow from the inlet to the outlet. 
         [0031]    Illustratively according to this aspect of the invention, the second conduit and the first conduit are connected together to permit fluid to flow from the fluid inlet toward the fluid outlet. 
         [0032]    Additionally illustratively according to this aspect of the invention, the first conduit and the second conduit are coupled together by a union that seals a first end of each of the first and second conduit so that fluid is inhibited from passing from the first end of the first conduit into the region between the first and second conduits adjacent the first end of the first conduit. 
         [0033]    Further illustratively according to this aspect of the invention, a second end of the second conduit is sealed with a cap to prevent fluid from flowing out of the second end of the second conduit. 
         [0034]    Further illustratively according to this aspect of the invention, a second end of the first conduit is spaced apart from the cap to permit fluid to flow from the second end of the first conduit adjacent the cap, and into the region between the first and second conduits. 
         [0035]    Additionally illustratively according to this aspect of the invention, the union is formed to include an outlet to permit fluid to flow from the first end of the second conduit out of the outlet. 
         [0036]    Further illustratively according to this aspect of the invention, the union includes a first end having an opening sized to receive the first end of the second conduit, and the union includes a second end having an opening sized to receive the first end of the first conduit. 
         [0037]    Further illustratively according to this aspect of the invention, the first and second ends of the union are separated by a generally frustoconical reducing region. 
         [0038]    Illustratively according to this aspect of the invention, the first and second fluid conduits are coupled so that fluid flowing within the first conduit flows substantially in the opposite direction as fluid flowing within the second conduit. 
         [0039]    Additionally illustratively according to this aspect of the invention, the apparatus further comprises a third fluid conduit, wherein at least a portion of the first fluid conduit is surrounded by the second and third fluid conduits, and at least a portion of the second fluid conduit is surrounded by the third fluid conduit. 
         [0040]    Further illustratively according to this aspect of the invention, the fluid flowing through and immediately adjacent to the first and third fluid conduits flows in a direction substantially parallel within each conduit. 
         [0041]    Illustratively according to this aspect of the invention, the apparatus further comprises a plurality of apertures in the second fluid conduit comprise a first aperture, a second aperture, and a third aperture, the first aperture being spaced from the second aperture by a first distance, and the second aperture being spaced from the third aperture a second distance, the first distance being greater than the second. 
         [0042]    Illustratively according to this aspect of the invention, the first and second fluid conduits define a void having a volume capable of receiving at least 0.13 gallons of fluid. 
         [0043]    Additionally illustratively according to this aspect of the invention, the first, second and third conduits define a void having a volume capable of receiving at least 0.9 gallons of fluid. 
         [0044]    Illustratively according to this aspect of the invention, the plurality of each of the apertures is substantially of one of the shapes selected from the group consisting of: circular, square, rectangular, diamond-shaped, ovular, triangular, and irregular. 
         [0045]    According to another aspect of the invention, a fluid mixing apparatus for use in a fluid flow network comprises a mixing valve including a housing having a hot fluid inlet, a cold fluid inlet, a mixed fluid outlet, a mixing region, and a movable valve assembly to adjust the relative flow of fluid through the hot fluid inlet and the cold fluid inlet, and a first fluid conduit in fluid communication with the mixing valve, the first fluid conduit including an inlet through which fluid flows from a hot fluid supply line and an outlet through which fluid flows toward the mixing valve, the first fluid conduit constructed to expose fluid flowing through the inlet to a heat sink. 
         [0046]    Illustratively according to this aspect of the invention, the heat sink is a second fluid mass downstream of a first fluid mass. Additionally illustratively according to this aspect of the invention, the apparatus further comprises a second fluid conduit coupled to the first fluid conduit, the first fluid conduit formed to include the inlet and formed to include a first conduit outlet through which fluid is capable of flowing out of the first fluid conduit and into the second fluid conduit. Further illustratively according to this aspect of the invention, the apparatus further comprises a third conduit between the first and second fluid conduits. Additionally illustratively according to this aspect of the invention, the first fluid conduit has a length, and is formed to include a plurality of openings, at least one of the plurality of openings positioned between the ends of the first fluid conduit. Additionally illustratively according to this aspect of the invention, a portion of the first fluid conduit is surrounded by the second fluid conduit. Additionally illustratively according to this aspect of the invention, at least one of the first and second fluid conduits includes a plurality of fins extending from a surface of said one of the first and second fluid conduits. Further illustratively according to this aspect of the invention, said one of the first and second fluid conduits is formed to include a plurality of apertures, at least one of said plurality of apertures positioned between the ends of the fluid conduit including fins. 
         [0047]    Illustratively according to this aspect of the invention, the heat sink is a thermally conductive material having a mass per unit of linear length of net fluid flow greater than the average mass per unit of linear length of net fluid flow in the fluid flow network. Additionally illustratively according to this aspect of the invention, the heat sink comprises copper. 
         [0048]    Illustratively according to this aspect of the invention, the heat sink surrounds the first conduit so that fluid flowing from the first fluid conduit subsequently flows through a passageway defined by the heat sink. 
         [0049]    According to another aspect of the invention a decontamination apparatus comprising a fluid heater, a cold fluid supply line, a hot fluid supply line for supplying hot fluid from the fluid heater to a thermostatic mixing valve, the thermostatic mixing valve having a hot fluid inlet for receiving fluid from to the hot fluid supply line, a cold fluid inlet for receiving fluid from the cold fluid supply line, and a mixed fluid outlet for supplying fluid to a mixed fluid supply line through which one, the other, or both of the hot and cold fluids flow from the thermostatic mixing valve, an emergency fixture connected to the mixed fluid supply line for supplying fluid therefrom to a user and configured to deliver the mixed fluid at a flow rate and pattern to decontaminate effectively at least a portion of the user&#39;s body, and a diffuser coupled between the hot fluid supply line and the thermostatic mixing valve for increasing the time over which a temperature change is observed at the hot fluid inlet. 
         [0050]    In another aspect of the invention a decontamination apparatus comprises a fluid supply inlet configured for coupling to a fluid supply source, a circulation network coupled to the fluid supply inlet and formed to include a first passageway in which a first fluid flows, a heater to heat the first fluid stream in the circulation network, a decontamination fixture connected to the circulation network to receive heated fluid from the heater, and a support interconnecting at least the heater, fluid circulation network, and the decontamination fixture to permit movement of the apparatus as a unit. 
         [0051]    Illustratively according to this aspect of the invention, the apparatus further comprises a mixing valve comprising a valve body formed to include a first fluid inlet to receive a first fluid from a first fluid line, a second fluid inlet to receive a second fluid from a second fluid line, and a mixed fluid outlet. Additionally illustratively according to this aspect of the invention, the mixing valve further includes a valve assembly operably coupled to a thermostat to move the valve assembly to adjust the flow of at least one of the first and the second fluids to control the mixed fluid temperature. 
         [0052]    Additionally illustratively according to this aspect of the invention, the support is a pallet into which the tines of a fork truck can be inserted to lift and move the apparatus as a unit. Additionally illustratively according to this aspect of the invention, the support is a frame having wheels coupled thereto so that a user can move the apparatus as a unit. Additionally illustratively according to this aspect of the invention, the decontamination fixture includes a valve operated by an actuator, and operation of the actuator causes fluid to flow from the circulation network through the mixing valve and through the decontamination fixture. Further illustratively according to this aspect of the invention, operation of the actuator causes the heater to ignite and heat the fluid flowing through the circulation network. 
         [0053]    Additionally illustratively according to this aspect of the invention, the apparatus further comprises a diffuser positioned in the circulation network to receive fluid from the heater, the diffuser configured to increase the time over which a temperature increase is observed at the inlet of the fluid from the heater to the mixing valve. 
         [0054]    Illustratively according to this aspect of the invention, the apparatus further comprises a fuel tank to store fuel usable by the heater to generate heat for heating the fluid in the circulation network. Additionally illustratively according to this aspect of the invention, the support is a frame having wheels coupled thereto so that a user can move the apparatus as a unit. 
         [0055]    Additionally illustratively according to this aspect of the invention, the heater is configured to heat fluid on demand as the fluid flows through the circulation network. 
         [0056]    Illustratively according to this aspect of the invention, the heater includes a storage tank and is configured to heat fluid and store the heated fluid in the storage tank. 
         [0057]    Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0058]    The detailed description particularly refers to the accompanying figures in which: 
           [0059]      FIG. 1  illustrates a decontamination apparatus for tempering fluid to rinse substances from body parts of a victim, the apparatus having a heat exchange unit, fuel source, decontamination fixture, fluid circulation network, diffuser, and mixing valve coupled with a support to facilitate transportation of the decontamination apparatus; 
           [0060]      FIG. 2  illustrates internal components of an illustrative heater for use with the decontamination apparatus of  FIG. 1 ; 
           [0061]      FIG. 3  illustrates a decontamination apparatus for tempering fluid including a heat exchange unit, fluid circulation network, decontamination fixture, diffuser, and mixing valve positioned on a support platform to facilitate transportation of the decontamination apparatus; 
           [0062]      FIG. 4  is a cross-sectional view of the diffuser shown in  FIG. 1 , taken along line  4 - 4  thereof, showing the first and second conduits cooperating to form a two-pass diffuser; 
           [0063]      FIG. 5  is a cross-sectional view of the diffuser shown in  FIG. 3 , taken along line  5 - 5  thereof, showing the first, second, and third conduits cooperating to form a two-pass diffuser; 
           [0064]      FIG. 6  is a perspective view of a decontamination fixture including a drench shower and an eyewash station; 
           [0065]      FIG. 7  is a perspective view of a conduit for a diffuser having a spiral fin projecting away from the centerline through the conduit; 
           [0066]      FIG. 8  is a cross-sectional view of a conduit for a diffuser having a plurality of holes formed therein; 
           [0067]      FIG. 9  is a cross-sectional view of a conduit for a diffuser similar to  FIG. 8  showing a hole having a diamond shape; 
           [0068]      FIG. 10  is a cross-sectional view of a conduit for a diffuser similar to  FIG. 8  showing a hole having an oval shape; 
           [0069]      FIG. 11  is a cross-sectional view of a conduit for a diffuser similar to  FIG. 8  showing a slot having a elongated rectangular shape; 
           [0070]      FIG. 12  is a cross-sectional view of a conduit for a diffuser similar to  FIG. 8  showing a hole having a trapezoidal shape; 
           [0071]      FIG. 13  is a cross-sectional view of a conduit for a diffuser similar to  FIG. 8  showing a plurality of circular holes spaced apart by varying distances; 
           [0072]      FIG. 14  is a fragmentary view of a portion of the heater of  FIG. 2 , showing a pilot assembly with an igniter and a flame sensor; 
           [0073]      FIG. 15  is a view of the pilot assembly of  FIG. 14  showing a pilot flame; 
           [0074]      FIG. 16  is a diagrammatic view of the heater of  FIG. 2 , showing a computer connected to a gas proportioning valve, to a flow sensor that is also coupled to the fluid inlet to the heater, and to a thermistor that is also coupled to the hot fluid outlet line, the heat exchanger and a fuel inlet line; 
           [0075]      FIG. 17  is a schematic view of the heater of  FIG. 2  showing safety circuitry including an overheat sensor, temperature limiter, and flue gas safety sensors and switches arranged in series and coupled to a valve to shut off flow of fuel upon detection of certain conditions; 
           [0076]      FIG. 18  is a diagrammatic view of a decontamination apparatus including a fluid supply, a heat exchanger receiving fluid from the fluid supply and feeding heated fluid to a diffuser, the diffuser feeding fluid to a mixing valve that, optionally, receives a supply of cold fluid from a cold fluid source, and a mixed fluid stream flowing from the mixing valve to an optional second diffuser then to an application; 
           [0077]      FIGS. 19A through 190  are graphical data, also shown in tabular form in Table 1, of a test performed with a circulation system including hot and cold inlets, a diffuser similar to the diffuser of  FIG. 5 , and a mixed fluid outlet coupled to the diffuser, wherein—♦—represents cold water, —▪—represents hot water, —▴—represents mixed water temperature, and —x—represents water pressure; and 
           [0078]      FIG. 20  is a diagrammatic view of a test apparatus showing a cold fluid supply, a hot fluid supply, a mixed fluid outlet, a diffuser coupled between the supplies and the mixed fluid outlet, and decontamination apparatus including a plurality of sensors coupled to the test apparatus to provide data. 
       
    
    
     DETAILED DESCRIPTION 
       [0079]    As illustrated in  FIG. 1 , a decontamination apparatus  20  includes a heat exchange assembly  22 , a fluid circulation network  24 , and a mixing valve  26 . In the embodiment of  FIG. 1 , the heat exchange assembly includes a heater  28  for supplying heat to a fluid for increasing the temperature of the fluid. To facilitate transportation of decontamination apparatus  20 , a support  32  is illustratively provided and is connected to fluid circulation network  24  and heat exchange assembly  22 . A plurality of wheels  34  and a stand  36  are coupled to frame  32 . Wheels  34  and stand  36  cooperate with support  32 , illustratively a frame  33 , to support fluid circulation network  24  and heat exchange assembly  22  in the position depicted in  FIG. 1 . 
         [0080]    Circulation network  24  includes fluid supply inlet  40  to which a fluid supply line  42  is couplable, fluid supply line  42  illustratively shown as a hose in  FIG. 1 . Fluid supply inlet  40  leads to a tee or other junction  44  at which fluid flowing through circulation network  24  is divided—a portion of the fluid flows into a cold fluid line  46  and a portion flows into hot fluid line  48 . Cold fluid line  46  extends from junction  44  to mixing valve  26 , and is coupled to cold inlet  50  of mixing valve  26 . Hot fluid line  48  extends from junction  44 , to heater  28 , and is coupled to mixing valve  26 . As fluid flows through hot fluid line  48  adjacent heater  28 , heat generated by heater  28  is applied to hot fluid line  48 , increasing the temperature of the fluid flowing therein. Hot fluid line  48  is coupled to hot inlet  52  of mixing valve  26 . Although  FIG. 1  discloses junction  44  as dividing a single supply line into the hot and cold fluid streams, it is within the scope of this disclosure to have separate hot and cold fluid supply lines supplying respective hot and cold fluids. 
         [0081]    As illustrated in  FIG. 1 , mixing valve  26  includes a housing  54  in which are mixed hot fluid flowing through hot inlet  52  and cold fluid flowing through cold inlet  50 . Illustratively, mixed fluid temperature is controlled using a suitable thermostat and valve assembly, as is known in the art. While reference is made to thermostatic mixing valves, it is within the scope of this disclosure to use other types of mixing valves or systems as are known in the art, illustratively proportional mixing techniques, pressure balancing valves, and the like. Mixed fluid flows from housing  54  through mixed fluid outlet  56 , and into mixed fluid line  58 . Mixed fluid line  58  leads to an emergency fixture depicted illustratively in  FIG. 1  as an eyewash fixture  37 . 
         [0082]    As illustrated in  FIG. 1 , circulation network  24  has positioned therein a first diffuser  30  between the portion of hot fluid line  48  adjacent heater  28  and hot inlet  52  of mixing valve  26 . Illustratively, circulation network  24  has positioned therein a second diffuser  30 A between mixed fluid outlet  56  from mixing valve  26  and eyewash fluid inlet line  38 . Eyewash fluid inlet line  38  includes a valve  39  therein that is operable by actuation of actuator  41 . When a user actuates actuator  41 , opening valve  39 , mixed fluid flows from mixed fluid outlet  56  through mixed fluid line  58 , toward eyewash fixture  37 , through eyewash fluid line  38 , and out eyewash outlets  43  of eyewash fixture  37 . Refuse fluid is captured, at least in part, by basin  45  and is permitted to exit by way of drain  47 . Illustratively, when a user actuates actuator  41 , a burner or other heating element (described more fully below) is ignited or otherwise powered to heat fluid flowing through hot fluid line  48 . Optionally, decontamination apparatus  20  can be provided as a mobile unit. 
         [0083]    As illustrated in  FIG. 1 , frame  33  includes side members  35  that are coupled to heater  28 . Side members  35  are coupled to a base  49  illustratively including an axle tube  51  coupled to lower ends of side members  35  and an axle (not shown) extending therethrough. Wheels  34  are coupled to the axle to facilitate transport of decontamination apparatus  20 . Base  49  of frame  33  further includes a platform  53  having a generally upwardly facing surface  55 . Handles  57  are coupled to side frame members  35  to further facilitate transport. Upper frame section  59  is connected to side members  35 , and illustratively is a generally rectangular tubular section that extends outwardly from side members  35  to provide additional support for heater  28 . Also connected to frame  33  are circulation network  24 , mixing valve  26 , fuel tank  112 , and emergency (eyewash) fixture  37 , whether directly connected to frame  33  or indirectly through other parts of decontamination apparatus  20 . To move decontamination apparatus  20 , a user simply disconnects any fluid supply line  42  connected to fluid supply inlet. The user positions a foot on axle tube  51  and pulls handles  57  in direction  61 , lifting stand  36  from engagement with the ground or floor. The user can then move decontamination apparatus  20  by guiding handles  57  and rolling the apparatus using wheels  34 . 
         [0084]    Other fixtures are possible and are within the scope of this disclosure. For example, a decontamination fixture having one or more sprayers or wands (not shown) may be included. Such a sprayer or wand could include a trigger or other actuator that can be actuated by a user. The sprayer or wand may include a spray nozzle to create a desired pattern of spray. A user can use such a sprayer or wand to direct the flow of fluid from the wand in a pattern and/or a direction selected by a user. 
         [0085]    As shown in  FIG. 3 , decontamination apparatus  320 , described in further detail below, is positioned on support  332 . Support  332  is a platform  333  upon which is positioned a heater  328 , emergency fixture  510 , and illustratively mixing valve  326 . Platform  333  includes a generally upwardly facing surface  335  sized to support heater  328  and emergency fixture  510  thereon. Support members  337  extend from platform  333  downwardly toward base  339 . Support members  337  are illustratively spaced apart from each other and are positioned to receive the tines of a fork truck, or other transportation or lifting device, therein to permit convenient transport of decontamination apparatus  320 . To move decontamination apparatus  320  from one location to another, any fluid supply lines, drain lines, and fuel (or other power source) lines are disconnected, and transportation or lifting device (not shown) is positioned in spaces between support members  337  and platform  333  is lifted so that support  332  and decontamination apparatus  320  are elevated above the ground or floor. Decontamination apparatus  320  is then moved to the desired location. 
         [0086]    While decontamination apparatus  20  of  FIG. 1  and decontamination apparatus  320  of  FIG. 3  are illustrative examples configured for convenient transport, using frame  20  of  FIG. 1  and using a fork-truck or similar device to transport apparatus  320  of  FIG. 3 , it is understood that other configurations are within the scope of this disclosure. Other portable, semi-portable, and non-portable configurations are contemplated. A self-contained fluid supply vessel may be provided instead of using water from a source such as a well, municipal water supply, or other similar water source. Such an apparatus could be transported using a transportation device such as a truck, automobile, military vehicle, train, helicopter, or other mode of transportation. A decontamination apparatus such as apparatus  320  of  FIG. 3  could be affixed using known methods to a structure in a building, for example, if portability of the apparatus is not desired. 
         [0087]    In one configuration rather than having a burner, beating element  314  is provided in an electric heater that enables a user to set the temperature of hot water in the hot water supply to achieve and maintain a higher temperature than is possible with typical residential water heater heating elements. In one exemplary configuration, a tubular heating element manufactured by Watlow Electric Manufacturing Company, 12001 Lackland Road, St. Louis, Mo., USA 63146 is capable of maintaining water at and above 180 degrees F. at typical flows for a sufficient time to satisfy requirements for emergency applications. Such heating elements are typically constructed to withstand higher temperatures and currents than standard residential heating elements. Further, thermostats associated with such heating elements are constructed to permit a user to select a temperature above about 185 degrees F. 
         [0088]    Referring to  FIG. 4 , diffuser  30  includes a first conduit  60  and a second conduit  62  surrounding, illustratively, a majority of first conduit  60 . First conduit  60  includes a first end  64  serving as an inlet of fluid to diffuser  30 , and an opposite second end  66 . Second conduit  62  includes a first end  74  serving as an outlet for fluid from diffuser  30  and an opposite second end  76 . As illustrated in  FIG. 4 , a cap  68  is coupled to second end  76  to close second conduit  62 . Cap  68  is coupled to second end  76  illustratively with solder applied around the perimeter of cap  68 . It is understood that this diffuser design is illustrative only and that it is within the scope of this disclosure for diffusers to be different in design. 
         [0089]    In the illustrative embodiment, diffuser  30  includes a union  70  to assist in positioning first conduit  60  relative to second conduit  62  and to assist in directing or guiding the flow of fluid through diffuser  30 . Union  70  is coupled to first ends  64 ,  74  of respective first and second conduits  60 ,  62 , illustratively with solder. Union  70  includes, at a first end  71  thereof, a first opening  72  to receive first end  74  of second conduit  62 . Union  70  includes, at a second end  73  thereof, a second opening  78  sized to receive first end  64  of first conduit  60 . 
         [0090]    Referring to  FIG. 4 , in operation, fluid enters diffuser  30  through first end  64  of first conduit  60  adjacent second end  73  of union  70 . Depending on the outlet configuration (described in more detail below), fluid generally flows in first direction  80  through first conduit  60  from its first end  64  to its second end  66 . Second end  66  is spaced apart from cap  68 , permitting fluid to exit second end  66  of first conduit  60  and reverse its direction to flow in a second direction  82 , opposite first direction  80 . First conduit  60  is positioned substantially within second conduit  62  so that when fluid exits second end  66 , the fluid remains within the volume defined by cap  68 , second conduit  62 , and portions of union  70 . 
         [0091]    As shown in  FIG. 4 , union  70  includes, between its first and second ends  71 ,  73 , a reducing region  75  that necks down or reduces the diameter of union  70  from a diameter sized to receive the outside diameter of second conduit  62  to a diameter sized to receive the outside diameter of first conduit  60 , thus forming a seal to prevent fluid from flowing from second conduit  62  out of the fluid circulation network between first conduit  60  and second end  73  of union  70 . Union  70  includes an outlet  86  formed between first end  71  thereof and reducing region  75 . Illustratively, reducing region  75  is frustoconical in shape. An outlet  86  surrounds an opening  88  formed in union  70  to permit fluid flowing in direction  82  to exit diffuser  30  and flow toward mixing valve  26 . 
         [0092]    As illustrated in  FIGS. 4 and 5 , optional spacers  89  are positioned between the conduits to discourage relative movement therebetween. Illustratively, spacers  89  are positioned adjacent second end  66  of first conduit  60  and about the circumference of first conduit  60  to maintain the relative position of first and second conduits  60 ,  62 . Spacers  89  are illustratively constructed using crimped pieces of copper alloy tubing commonly used in the plumbing industry. If included, spacers  89  may, however, be constructed using any suitable material(s) and may have any shape sufficient to maintain the relative position of conduits in a diffuser such as diffuser  30  and still permit adequate flow of fluid therethrough. 
         [0093]    A first diffuser outlet configuration is depicted in diffuser  30  of  FIG. 4 . A series of apertures  90 , designated individually as  90 A through  90 K, are formed in first conduit  60  at various positions around first conduit  60  and along its length. Apertures  90  A, B, and C are formed in, approximately, the first half  92  of the length of first conduit  60 . Apertures  90  D through K are positioned in, approximately, the second half  94  of the length of first conduit  60 . Because apertures  90 A through  90 K are positioned along the length of first conduit  60 , portions of fluid flowing through first conduit  60  exit through apertures  90  and mix with fluid flowing outside of first conduit  60  and in second conduit  62 . Illustratively, conduit  60  has an inside diameter of about 0.8 inches and has an overall length C of about 29 inches, and conduit  62  has an inside diameter of about 1.25 inches and has an overall length A of about 24.25 inches. Second end  66  is spaced apart from cap  68  by a distance of B, illustratively about 0.75 inches. However, it is understood that other sizes for conduit  62  are within the scope of this invention. 
         [0094]    As ‘fresh’ hot fluid (a second mass of fluid) that has been recently heated by heater  28  first flows through first conduit  60 , the fresh hot fluid mixes with the previously stagnant fluid that was in first conduit  60  and is in second conduit  62 . Because apertures  90 A- 90 J are provided along the length of first conduit  60 , some of the fresh hot fluid flows through the first apertures  90  (for example  90 A,  90 B and  90 C) encountered by the fluid flow without flowing all the way to second end  66  of conduit  60 , thus blending the fluid and rendering the blended fluid a temperature between the temperature of the second mass of fluid and the stagnant fluid (a first mass of fluid) temperature. As more fresh hot fluid flows into first conduit  60 , the blended temperature gradually approaches that of the fresh hot fluid. By blending the fluids as such, the fresh hot fluid does not reach mixing valve  26  at full temperature all at once, but rather reaches mixing valve  26  blended with previously stagnant fluid, thus providing the mixing valve a gradual increase in fluid temperature instead of the more immediate increase obtained without this blending. 
         [0095]    First diffuser outlet configuration depicted in  FIG. 4  illustrates apertures  90 A through  90 J formed as holes in first conduit  60  on generally opposite sides of the conduit, formed, for example, by drilling through a first point along the length of first conduit  60  and permitting the drilling device to penetrate through the opposite side of the conduit. It is understood, however, that any number of apertures  90 A through  90 J may be provided along the length and circumference of conduit  60 . In the illustrative embodiment, aperture  90 A is positioned about 13 inches from first end  64 . Aperture  90 B is positioned about 17 inches from first end  64 . Aperture  90 C is positioned about 19 inches from first end  64 . Aperture  90 D is positioned about 21 inches from first end  64 . Aperture  90 E is positioned about 1 inch from aperture  90 D. Apertures  90 F through  90 K are each positioned from the immediately adjacent aperture approximately the same distance as apertures  90 D and  90 E are spaced apart. Illustratively, apertures  90 A-J are holes drilled through conduit  60  so that a pair of holes, each 180 degrees around the circumference of conduit  60  from the other, is at each position along the length of first conduit  60 . Illustratively, apertures  90  are holes of 0.125 inch diameter drilled in conduit  60 ; however, apertures  90 A-J may be of different sizes and shapes and each may be different from one or more other apertures. 
         [0096]    Although certain illustrative outlet configurations are disclosed herein, it is within the scope of this disclosure to use any suitable shape of aperture or combination of shapes. It is also within the scope of this disclosure to space a wide range of sizes and numbers of such apertures  90  apart from one another by various distances to achieve a desired mixing of fluid inside an internal conduit with the fluid outside the internal conduit, and to maintain adequate flow through the diffuser. By way of example, additional outlet configurations are depicted in  FIGS. 8 through 13 . 
         [0097]    As shown in  FIGS. 1 and 2 , a portion of hot fluid line  48  passes adjacent heater  28  to receive heat generated by heater  28  and heat the fluid flowing through hot fluid line  48 . Illustratively, hot fluid line  48  is constructed of a copper alloy; however, use of other suitable materials are within the scope of this disclosure. For example, steel, aluminum, brass, stainless steel, and other alloys or materials that have desirable characteristics such as adequate strength, durability, corrosion resistance, and high heat transfer rates, and are suitable in particular applications. 
         [0098]    As shown in  FIG. 2 , illustrative heater  28  includes a heat exchange chamber  806  through which hot fluid line  48  passes with cool fluid entering through portion  810  of hot fluid line  48  and exiting through portion  807 . Illustrative heat exchange chamber  806  is sized to receive burner  114  in its base region  122 . Heat exchange chamber  806  is illustratively rectangular in shape and has a plurality of fins  124  extending from a first side wall  126  to a second, opposite side wall  128 . As shown in  FIG. 1 , heater  28  includes a flue  130 , the bottom  132  of which is sized to approximate the size of top  134  of draught diverter  805 , the bottom  840  of which is coupled to the top  842  of heat exchange chamber  806 . Excess heat and exhaust from the combustion process passes from heat exchange chamber  806  through flue  130  and exits through top  136  of flue  130  to the atmosphere or other suitable destination. A suitable heater  28  is available in the form of a water heater model number  125  FX from Robert Bosch Corporation, Broadview, Ill., USA, although other heat exchangers are suitable, as are known in the art. 
         [0099]    As shown in  FIG. 1 , heater  28  includes a fuel line  110  coupled to fuel tank  112 . The burner  114 , shown in  FIG. 2 , is sized to fit within the bottom  844  of heat exchanger  806  and couples to a fuel valve  814  that is configured to control the flow of fuel from fuel line  110  to burner  114 . Illustratively, fuel valve  814  is responsive to a controller system  118 , shown and described in more detail below with reference to  FIGS. 16 and 17 , or may have a manual control such as on/off switch  833 , by which fuel valve  814  opens upon certain conditions to provide fuel. If on/off switch  833  is used, the switch may be accessed through opening  803  in cover  801 , which fits around heat exchange chamber  806 , burner  114 , and fuel valve  814 . Fuel is supplied via ports  835  and  836  and, illustratively, controller system  118  and fuel valve  814  cooperate to open fuel valve  814  and ignite fuel at burner  114  when actuator  41  is actuated by a user. It is within the scope of this disclosure for a variety of types of equipment to be used instead of or in addition to controller system  118  to determine whether, for example, power or fuel to heater  28  should be increased, or whether heater  28  should be started or ignited. For example, a typical flow sensor could be incorporated to detect flow of fluid in hot fluid line  48 , and when flow is detected in line  48 , heater  28  is ignited. Further, a thermocouple to detect the temperature of fluid flowing through hot fluid line  48  could likewise be incorporated. If fluid was flowing through hot fluid line  48  and the thermocouple detected a temperature below a set point, heater  28  could be started or otherwise turned up. It is understood that heater  28  is illustrative, and other heater configurations are within the scope of this disclosure. 
         [0100]    As illustrated in the diagram of  FIG. 16 , cold fluid entering the heater passes through a valve assembly that allows gas to enter the burners only when fluid is flowing. A fluid flow sensor  728  signals computer  729  to light burner  732 , and the gas is ignited in the illustrative gas-fueled example by the pilot or spark ignition. Illustratively, burners  732  activate at a flow rate of 0.75 gallons per minute (GPM), with about 0.6 gpm continuous flow required to maintain burners  732  lit. Fluid is heated as it flows through heat exchanger  730 , which illustratively includes finned tube copper coils located adjacent burners  732 . As the fluid flow rate changes, a governor (not shown) modulates the flow of gas to burners  732  to maintain a constant temperature. The size of the flames and the energy used is thus proportional to the volume of hot fluid being moved through the system. The fluid temperature can be adjusted, illustratively from about 100° to about 140° F., by adjusting gas proportioning valve  734 . 
         [0101]    Referring to  FIGS. 14 and 15 , a flame sensor  620  of heater  28  (shown in  FIGS. 1 and 2 ) optionally may be positioned on pilot assembly  621  to sense when a flame  622  is present ( FIG. 15 ), and to shut off the supply of gas upon failure of flame  622  ( FIG. 14 ). As shown in  FIG. 17 , optionally a flue gas sensor  713 , a high temperature limiter  707 , and an overheat sensor  706  illustratively positioned in the flue, are coupled in series to an electronic control box  708 , that controls a valve (not shown), the valve closing upon a signal from any one or more of these sensors to stop the flow of gas. Flow sensor  728 , shown in  FIG. 16  senses when the flow of fluid is stopped, similarly signaling to close a valve and shut off the flow of gas to the burners. Illustratively, heater  28  includes a push button piezo-electric pilot  624  shown in  FIGS. 14 and 15 , and as  705  in  FIG. 17 , safety interlocked controls, and an illustrative copper heat exchanger  730  illustrated in  FIG. 16 . Further, illustratively heater  28  includes a slow ignition valve, high-efficiency low-maintenance stainless steel burners  732 , and filters (not shown) for the pilot and burners to provide clogging protection. 
         [0102]    An alternative embodiment of a diffuser  230  is illustrated in  FIG. 5 . Diffuser  230  is illustrated as a three-pass diffuser and includes first conduit  232 , a second conduit  234 , and a third conduit  236 . As shown in  FIG. 5 , first conduit  232  is positioned substantially within second conduit  234 , and second conduit  234  is positioned substantially within third conduit  236 . A first union  238  cooperates with first, second, and third conduits  232 ,  234 ,  236  to maintain the conduits in position. First union  238  includes a first section  240  and a second section  242 . First section  240  includes a smaller diameter opening  244  sized to receive first conduit  232  therein. First section  240  includes a larger diameter opening  246  sized to receive the second conduit  234  therein. First section  240  includes a reducing or neck down region  248  between openings  244  and  246 . Illustratively, reducing region  248  is frustoconical in shape. Second section  242  includes a smaller diameter opening  250  sized to receive the second conduit  234 . Second section  242  includes a larger diameter opening  252  sized to receive the outside diameter of third conduit  236 . Second section  242  includes a reducing or neck down region  254  between openings  250  and  252 . Illustratively, reducing region  254  is frustoconical in shape. First section  240  and second section  242  of first union  238  may be provided as two separate pieces or may optionally be formed as a single first union part. 
         [0103]    Diffuser  230  further includes a second union  256  spaced apart from first union  238 . Second union  256  includes a larger diameter opening  258  sized to receive an outlet end  260  of third conduit  236 . Second union  256  includes a smaller diameter opening  262  sized for coupling to a hot fluid line  264 . Second union  256  includes a reducing or neck down region  266  between openings  258 ,  262 . Illustratively, reducing region  266  is frustoconical in shape. End cap  226  has a side  227  sized to receive a second end  239  of second conduit  324 . 
         [0104]    While the reducing regions described above are shown and described as being frustoconical in shape, it is within the scope of this disclosure for one or more of the reducing regions to be other shapes. Further, although unions are described as being separate components from the conduits, it is within the scope of this disclosure to form diffusers from any number of pieces or to mold diffusers from a single piece. One of ordinary skill in the art will recognize that a wide variety of formation and/or assembly techniques may be implemented to make a diffuser. 
         [0105]    First conduit  232  has a length F, illustratively about 53-54 inches. Second conduit  234  has a length E, illustratively about 50-51 inches. Third conduit  236  has a length D, illustratively about 48 inches. Illustratively, first, second, and third conduits  232 ,  234 ,  236  have inside diameters of about 1, 1.5, and 2.5, inches respectively. Diffuser  230  outlet configuration depicted in  FIG. 5  illustrates apertures  290 A through  290 Q formed as holes in first conduit  232  and second conduit  234 , each hole illustratively having a second corresponding hole on generally opposite sides of the conduit, formed, for example, by drilling through a first point along the length of the conduit and permitting the drilling device to penetrate through the opposite side of the conduit. While two opposite holes are described for each of apertures  290 A through  290 Q, such is illustrative, and any number of holes of any shape are within the scope of this invention. 
         [0106]    The sizes and spacing of the apertures  290  are described for illustrative purposes herein. As shown, illustrative apertures  290 A are 7/64 inch holes positioned in first conduit  232  about 12 inches from first end  233  of first conduit  232 , apertures  290 B are 3/32 inch holes positioned about 24 inches from first end  233 , apertures  290 C are 5/64 inch holes positioned about 36 inches from first end  233 , apertures  290 D are 1/16 inch holes positioned about 48 inches from first end  233 , and apertures  290 E are 1/16 inch holes positioned about 2 inches from second end  235 . 
         [0107]    Still referring to  FIG. 5 , illustrative apertures  290 F are 9/16 inch holes positioned about 3.5 inches from first end  237  of second conduit  234  or adjacent the reducing region  254  of the second section  242  of first union  238 . Illustrative apertures  290 G are 9/16 inch holes positioned about 4.0 inches from first end  237  of second conduit  234 , and are rotated 90 degrees around the circumference of second conduit  234  relative to apertures  290 F. Illustrative apertures  290 H are 9/16 inch holes positioned about 4.5 inches from first end  237  of second conduit  234 , and are rotated 90 degrees around the circumference of second conduit  234  relative to apertures  290 G. Illustrative apertures  290 I are 9/16 inch holes positioned about 5.0 inches from first end  237  of second conduit  234 , and are rotated 90 degrees around the circumference of second conduit  234  relative to apertures  290 H. Illustrative apertures  290 J are 9/16 inch holes positioned about 5.5 inches from first end  237  of second conduit  234 , and are rotated 90 degrees around the circumference of second conduit  234  relative to apertures  290 I. Illustrative apertures  290 K are 9/16 inch holes positioned about 6.0 inches from first end  237  of second conduit  234 , and are rotated 90 degrees around the circumference of second conduit  234  relative to apertures  290 J. Illustrative apertures  290 L are 9/16 inch holes positioned about 6.5 inches from first end  237  of second conduit  234 , and are rotated 90 degrees around the circumference of second conduit  234  relative to apertures  290 K. Illustrative apertures  290 M are 9/16 inch holes positioned about 7.0 inches from first end  237  of second conduit  234 , and are rotated 90 degrees around the circumference of second conduit  234  relative to apertures  290 L. Illustrative apertures  290 N are 3/32 inch holes positioned about 38.0 inches from second end  239  of second conduit  234 . Illustrative apertures  290 P are 3/32 inch holes positioned about 20.0 inches from second end  239  of second conduit  234 . Illustrative apertures  290 Q are 3/32 inch holes positioned about 20.0 inches from second end  239  of second conduit  234 . 
         [0108]    It is understood that fluid entering diffuser  230  at first end  233  of first conduit  232  flows upward to end cap  226 , then flows downward between first conduit  232  and second conduit  234 , down to aperture  290 F, and then flows upward again between second conduit  234  and third conduit  236 , up to and out through hot fluid line  264 . As fluid flows past each of the apertures  290 A through  290 Q, newly heated fluid may flow through the apertures to mix with stagnant water that may already be in diffuser  230 . 
         [0109]    An alternative heater embodiment, heater  328 , is depicted in  FIG. 3 . Heater  328  is a standard “residential” water heater, illustratively a 119 gallon water heater including a fuel line  310  coupled to fuel tank  312  and burner  314 . A fuel valve (not shown) may be coupled to fuel line  310  to control flow of fuel to burner  314 , and may be responsive to a controller (not shown) to provide fuel when the controller senses that additional heat is to be supplied to increase the temperature of fluid stored in heater  328 . Many fuels may be used, for example natural gas, propane, or other suitable fuel types. One of ordinary skill in the art will appreciate that an electric water heater could be used for illustrative heater  328 . 
         [0110]    Heater  328  further includes a storage tank  302  in which fluid is stored that enters storage tank  302  through a fluid inlet line  340 . As shown in  FIG. 3 , a heat exchange region  321  includes an interface  323  adjacent burner  314 . Interface  323  may take a number of forms, and may include a circuit through which hot combustion gases flow such as a coil, a generally flat surface, or a heat sink extending into fluid stored in storage tank  320  to increase the surface area of interface  323  in contact with fluid in storage tank  320 . If heater  328  is an electric heater, an electric element electrically coupled to an electric source could heat the fluid in storage tank  320 . Optionally, a filter  347  may be provided, illustratively in fluid inlet line  340 , to filter out particulate matter. Filters may be provided elsewhere in the system, illustratively in cold fluid line  346 . 
         [0111]    As shown in  FIG. 3 , a mixing valve  326  receives hot fluid from hot fluid line  348  and cold fluid from cold fluid line  346 . As with the embodiment described with reference to  FIG. 1 , mixing valve  326  mixes hot and cold fluids and supplies tempered water through mixed fluid line  350 . A diffuser, illustratively diffuser  230  of  FIG. 5 , is coupled to hot fluid inlet line  348  and is between mixing valve  326  and the fluid outlet from heater  328 . An illustrative mixing valve is disclosed in U.S. Pat. No. 5,647,531 assigned to Lawler Manufacturing Company, Inc. of Indianapolis, Ind., the disclosure of which is hereby incorporated by reference herein. Other mixing valves of various configurations may be used depending on the specific requirements of the application in which the subject matter hereof is incorporated. 
         [0112]    Still referring to  FIG. 3 , when a user actuates actuator  521 ,  526 , or  532 , opening a valve  522 ,  534 , mixed fluid flows from mixed fluid outlet of the mixing valve and through mixed fluid line  350 , toward fixture  510 . 
         [0113]    As shown in  FIGS. 3 and 6 , a combination emergency fixture  510  is illustrated. Emergency fixture  510  includes a tempered fluid inlet  512  receiving tempered water from a source such as the system shown in  FIG. 3 . Emergency fixture  510  includes a fluid supply line  514  coupled to fluid inlet  512 , the fluid supply line being coupled to an eyewash supply line  516  and a emergency shower supply line  518 . Eyewash supply line  516  is coupled to an eyewash outlet fixture  520  so that, when eyewash actuator  521  and valve  522  is actuated, fluid flows from fluid inlet  512  through fluid supply line  514 , into eyewash supply line  516 , and out eyewash outlet fixture  520 . Basin  524  is provided to catch at least part of the refuse fluid and divert the discarded fluid into a drain line  525 . An optional foot actuator  526  is coupled with a link  528  to valve  522  so that a user can actuate the eyewash by stepping on foot actuator  526 . Combination emergency fixture  510  further includes an emergency shower fixture  530  coupled to the emergency shower supply line  518 . A shower actuator  532  is operably coupled to a valve  534  so that when a user actuates shower actuator  532 , tempered fluid flows from fluid inlet  512  through fluid supply line  514 , into emergency shower supply line  518 , and out emergency shower fixture outlet  536 . 
         [0114]    It is within the scope of this disclosure for heaters  28 ,  328  to be replaced with another suitable heating device, for example a shell and tube heat exchanger—having a heating fluid flowing therethrough (when access is had to such a heating fluid possessing sufficient heat to raise the temperature of supplied fluid by an acceptable amount). 
         [0115]    Diffusers  30 ,  230  are illustratively constructed using a copper alloy. In these examples, copper is selected because of its high heat transfer rate, and resultant ability to dissipate heat contained in fluid flowing through diffusers  30 ,  230 . However, one of ordinary skill in the art will recognize that many other materials could be used that provide desirable properties such as machinability, durability, corrosion resistance, compatibility with other system materials, cost, and the like. 
         [0116]    In a further illustrative embodiment represented in  FIG. 7 , a conduit  410  is depicted. Conduit  410  may serve as the inner conduit of a diffuser, the outer conduit, or a conduit between the outer and inner conduit in a three (or more) pass diffuser. Conduit  410  includes an internal passageway  412  and an external surface  414 . As shown in  FIG. 7 , external surface  414  includes a plurality of fins  416 . Fins  416  are actually shown as a single spiral fin created using an extrusion process in which a thick-walled, illustratively copper alloy, tube is extruded to form fins  416  from surface  414 . An integral finned surface  418  is thus formed on conduit  410 . Fins  416  increase the surface area of external surface  414  and thus increase heat transfer into adjacent matter such as fluid flowing outside of conduit  410 . It is within the scope of this disclosure to include a separate finned surface  418  constructed from a different piece of material than conduit  410  and connect separate finned surface  418  to conduit  410  to permit heat transfer during operation from conduit  410  into separate finned surface  418 . It is within the scope of this disclosure to form fins  416  independently instead of as a single, spiral fin. Conduit  410  could serve as an external conduit, middle conduit (such as in a three-pass diffuser configuration) or an inner conduit. A finned conduit may be used instead of or in addition to a conduit with plurality of apertures, or, alternatively, the finned conduit may be provided with one or more apertures, to provide additional mixing. 
         [0117]    Referring now to  FIGS. 8 through 13 , various aperture configurations are depicted for the apertures provided in the diffusers. These aperture configurations are provided on the internal conduits—in other words, depending on the number of passes fluid makes through a particular diffuse line, all conduits except for the outermost conduit may, or may not, include such aperture configurations. Any number of passes may be made through a diffuser, however consideration of physical, practical, and cost factors suggest that diminishing returns exist beyond a maximum number of passes. However, this maximum number of passes may vary depending on such factors as system size, pressure, and flow rate, for example. Generally, a higher number of passes should improve mixing between a first mass of fluid and a second mass of fluid adjacent the first mass upon entry into the diffuser. Further, a higher number of passes should improve heat transfer between such a first and second fluid mass, from the fluid mass(es) and to the diffuser material. 
         [0118]      FIG. 8  shows a plurality of apertures  90  evenly spaced along the length of conduit  60 .  FIG. 13  similarly shows a plurality of apertures  690 A through  690 E. However, apertures  690 A through  690  E are depicted as not evenly spaced. For example, Apertures  690 D and  690 E are more closely spaced than apertures  690 A and  690 B, and illustratively the spacing gradually decreases from  690 A to  690 E. A combination arrangement is shown in  FIG. 4 , with spacing gradually decreasing in first half  92  from aperture  90 A to aperture  90 D, and the spacing remaining essentially consistent between apertures in second half  94 , from aperture  90 D to aperture  90 K. Apertures  95 - 98  in  FIGS. 9-12  depict a variety of illustrative shapes including rhomboid, ovoid, rectangular, and parallelogram shapes. However, it is understood that these shapes are illustrative only, and that other shapes, including irregular shapes, may be included and are within the scope of this disclosure. Additionally, any shape aperture may be used with any aperture spacing to achieve the desired mixing effect of fluid in the conduit. 
         [0119]      FIG. 8  illustrates substantially circular holes,  FIG. 9  illustrates a substantially diamond (rhomboid) aperture,  FIG. 10  illustrates a substantially oval aperture,  FIG. 11  illustrates a substantially rectangular aperture,  FIG. 12  illustrates an angularly-oriented parallelogram-shaped aperture, and  FIG. 13  illustrates a series of apertures positioned at points A, B, C, D, and E along conduit  660 . 
         [0120]    Diffusers  30 ,  230  may also serve as heat sinks. The heat sink is a thermally conductive structure that has a mass per unit of linear length of net fluid flow greater than the average mass per unit of linear length of net fluid flow in the overall fluid flow network. Illustratively, the heat sink comprises copper. In one exemplary configuration, the heat sink surrounds a first fluid conduit such as conduits  60 ,  232  of  FIGS. 4 and 5 , so that fluid flowing from the first fluid conduit subsequently flows through a passageway defined by or otherwise through the heat sink. Further, while the diffusers illustrated herein are used in conjunction with portable emergency fixtures, it is understood that the diffusers may be used with any fixture for which temperature control is desired. Such fixtures include fixed stationary emergency fixtures, as well as sinks, showers, and any other fluid fixture. The diffusers illustrated herein may also be used in combination with hot water heaters, for whatever purpose, wherein the diffuser would be installed in the hot water line exiting from the hot water heater. Other applications for the diffusers are possible. 
         [0121]    The following chart contains data from a test performed using a diffuser similar to the diffuser shown in  FIG. 3 : 
       Example 1 
       [0122]      
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Temperature 
                 Temperature 
                 Temperature 
                 Pressure of 
               
               
                   
                 (° F.) of 
                 (° F.) of 
                 (° F.) of 
                 hot water at 
               
               
                 Time 
                 Cold Water 
                 Hot Water 
                 Mixed Water 
                 mixing point 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 3:00:42 PM 
                 43.4509 
                 171.7 
                 84.6336 
                 1.92 
               
               
                 3:00:52 PM 
                 43.3573 
                 171.924 
                 84.8198 
                 3.02 
               
               
                 3:01:02 PM 
                 43.3417 
                 172.67 
                 85.6164 
                 6.55 
               
               
                 3:01:12 PM 
                 43.4275 
                 173.252 
                 144.085 
                 6.40 
               
               
                 3:01:22 PM 
                 43.4119 
                 173.739 
                 165.607 
                 7.14 
               
               
                 3:01:32 PM 
                 43.4275 
                 174.084 
                 169.902 
                 6.42 
               
               
                 3:01:42 PM 
                 43.4509 
                 174.396 
                 171.483 
                 7.07 
               
               
                 3:01:52 PM 
                 43.5757 
                 174.592 
                 171.985 
                 6.91 
               
               
                 3:02:02 PM 
                 44.0981 
                 174.896 
                 172.683 
                 6.65 
               
               
                 3:02:12 PM 
                 45.1031 
                 175.031 
                 172.92 
                 6.81 
               
               
                 3:02:22 PM 
                 46.2003 
                 175.024 
                 173.34 
                 7.12 
               
               
                 3:02:32 PM 
                 47.0322 
                 175.207 
                 173.489 
                 7.12 
               
               
                 3:02:42 PM 
                 47.7779 
                 175.274 
                 173.638 
                 7.11 
               
               
                 3:02:52 PM 
                 48.3911 
                 175.301 
                 173.807 
                 6.98 
               
               
                 3:03:02 PM 
                 45.5001 
                 175.288 
                 173.699 
                 3.03 
               
               
                 3:03:12 PM 
                 44.2462 
                 175.031 
                 121.81 
                 2.32 
               
               
                 3:03:22 PM 
                 44.1292 
                 174.592 
                 95.1776 
                 1.99 
               
               
                 3:03:32 PM 
                 43.9032 
                 174.497 
                 91.0316 
                 2.85 
               
               
                 3:03:42 PM 
                 43.9655 
                 174.166 
                 89.2846 
                 3.01 
               
               
                 3:03:52 PM 
                 44.1994 
                 173.936 
                 88.4988 
                 1.58 
               
               
                 3:04:02 PM 
                 43.7784 
                 173.821 
                 87.9795 
                 2.06 
               
               
                 3:04:13 PM 
                 43.5133 
                 173.631 
                 87.8607 
                 2.73 
               
               
                 3:04:23 PM 
                 43.3495 
                 173.577 
                 87.6083 
                 1.67 
               
               
                 3:04:33 PM 
                 43.2715 
                 173.36 
                 83.1573 
                 1.27 
               
               
                 3:04:43 PM 
                 43.1544 
                 173.266 
                 81.656 
                 1.91 
               
               
                 3:04:53 PM 
                 43.131 
                 173.184 
                 81.2523 
                 1.39 
               
               
                 3:05:03 PM 
                 43.0842 
                 173.089 
                 81.1551 
                 2.66 
               
               
                 3:05:13 PM 
                 43.0452 
                 173.029 
                 80.9755 
                 2.32 
               
               
                 3:05:23 PM 
                 42.9437 
                 172.981 
                 80.9306 
                 0.05 
               
               
                 3:05:33 PM 
                 42.9906 
                 172.758 
                 81.1326 
                 0.03 
               
               
                 3:05:43 PM 
                 43.014 
                 172.649 
                 81.3495 
                 0.03 
               
               
                 3:05:53 PM 
                 43.014 
                 172.52 
                 82.1269 
                 0.03 
               
               
                 3:07:30 PM 
                 45.8493 
                 170.537 
                 84.7979 
                 0.03 
               
               
                 3:07:32 PM 
                 45.966 
                 170.537 
                 84.7979 
                 0.03 
               
               
                 3:07:35 PM 
                 46.0516 
                 170.496 
                 84.783 
                 0.03 
               
               
                 3:11:16 PM 
                 45.6476 
                 164.755 
                 89.4627 
                 0.03 
               
               
                 3:11:26 PM 
                 45.7643 
                 164.618 
                 89.3071 
                 0.03 
               
               
                 3:11:36 PM 
                 45.7176 
                 164.434 
                 89.1515 
                 0.03 
               
               
                 3:11:46 PM 
                 45.7487 
                 164.243 
                 89.0329 
                 0.03 
               
               
                 3:11:56 PM 
                 45.9277 
                 165.308 
                 97.7428 
                 6.52 
               
               
                 3:12:06 PM 
                 47.0629 
                 166.746 
                 148.545 
                 6.84 
               
               
                 3:12:16 PM 
                 47.3194 
                 168.571 
                 159.367 
                 6.98 
               
               
                 3:12:26 PM 
                 47.2727 
                 170.29 
                 162.992 
                 6.92 
               
               
                 3:12:36 PM 
                 47.3349 
                 170.752 
                 165.43 
                 5.59 
               
               
                 3:12:46 PM 
                 46.2389 
                 170.847 
                 159.882 
                 2.24 
               
               
                 3:12:56 PM 
                 46.0678 
                 170.989 
                 106.999 
                 3.43 
               
               
                 3:13:06 PM 
                 46.06 
                 171.111 
                 99.4216 
                 3.38 
               
               
                 3:13:16 PM 
                 45.8733 
                 171.478 
                 97.6253 
                 2.34 
               
               
                 3:13:26 PM 
                 45.492 
                 171.762 
                 93.4761 
                 2.47 
               
               
                 3:13:36 PM 
                 45.0872 
                 172.068 
                 92.192 
                 2.40 
               
               
                 3:13:46 PM 
                 44.5108 
                 172.244 
                 91.8522 
                 2.85 
               
               
                 3:13:56 PM 
                 44.1991 
                 172.461 
                 91.5567 
                 1.63 
               
               
                 3:14:06 PM 
                 43.934 
                 172.616 
                 91.2092 
                 2.70 
               
               
                 3:14:16 PM 
                 43.8405 
                 172.691 
                 91.1279 
                 3.16 
               
               
                 3:14:26 PM 
                 43.7859 
                 172.766 
                 91.0466 
                 1.84 
               
               
                 3:14:36 PM 
                 43.7079 
                 172.874 
                 88.8771 
                 3.14 
               
               
                 3:14:46 PM 
                 43.7157 
                 172.942 
                 88.5583 
                 2.85 
               
               
                 3:14:56 PM 
                 43.6767 
                 172.921 
                 88.3432 
                 2.49 
               
               
                 3:15:06 PM 
                 43.6303 
                 172.981 
                 88.343 
                 2.31 
               
               
                 3:15:16 PM 
                 43.5835 
                 172.893 
                 88.573 
                 2.65 
               
               
                 3:15:26 PM 
                 43.5211 
                 172.873 
                 88.573 
                 1.64 
               
               
                 3:15:36 PM 
                 43.4197 
                 172.866 
                 88.5136 
                 3.12 
               
               
                 3:15:46 PM 
                 43.3417 
                 172.839 
                 88.0759 
                 2.40 
               
               
                 3:15:56 PM 
                 43.2559 
                 172.656 
                 76.8887 
                 2.40 
               
               
                 3:16:06 PM 
                 43.209 
                 172.534 
                 76.9037 
                 1.41 
               
               
                 3:16:16 PM 
                 43.2012 
                 172.5 
                 80.2271 
                 0.03 
               
               
                 3:16:26 PM 
                 43.209 
                 172.331 
                 80.1597 
                 1.91 
               
               
                 3:16:36 PM 
                 43.2246 
                 172.737 
                 91.7855 
                 7.00 
               
               
                 3:16:46 PM 
                 43.2246 
                 173.238 
                 157.181 
                 7.02 
               
               
                 3:16:56 PM 
                 43.2246 
                 173.672 
                 168.195 
                 6.79 
               
               
                 3:17:06 PM 
                 43.2402 
                 173.956 
                 170.493 
                 6.81 
               
               
                 3:17:16 PM 
                 43.2559 
                 174.301 
                 171.585 
                 6.93 
               
               
                 3:17:26 PM 
                 43.2793 
                 174.423 
                 172.222 
                 6.69 
               
               
                 3:17:37 PM 
                 43.3105 
                 174.653 
                 172.859 
                 6.98 
               
               
                 3:17:47 PM 
                 43.3963 
                 174.72 
                 171.266 
                 0.03 
               
               
                 3:17:57 PM 
                 43.6069 
                 174.639 
                 170.88 
                 0.03 
               
               
                 3:18:07 PM 
                 43.9804 
                 174.581 
                 170.149 
                 0.03 
               
               
                 3:18:17 PM 
                 44.6039 
                 173.552 
                 170.522 
                 1.87 
               
               
                 3:18:27 PM 
                 44.1987 
                 173.187 
                 116.597 
                 3.45 
               
               
                 3:18:37 PM 
                 44.1753 
                 173.816 
                 105 
                 4.21 
               
               
                 3:18:47 PM 
                 44.2299 
                 173.776 
                 107.761 
                 6.24 
               
               
                 3:18:57 PM 
                 44.2299 
                 173.952 
                 142.44 
                 5.79 
               
               
                 3:19:07 PM 
                 44.1831 
                 174.08 
                 158.029 
                 5.79 
               
               
                 3:19:17 PM 
                 44.261 
                 174.33 
                 160.143 
                 5.79 
               
               
                 3:19:27 PM 
                 44.339 
                 174.303 
                 154.455 
                 5.66 
               
               
                 3:19:37 PM 
                 44.3623 
                 174.249 
                 150.432 
                 5.59 
               
               
                 3:19:47 PM 
                 44.3857 
                 174.445 
                 149.94 
                 5.84 
               
               
                 3:19:57 PM 
                 44.5805 
                 174.398 
                 148.83 
                 0.03 
               
               
                 3:20:07 PM 
                 44.6221 
                 174.299 
                 118.859 
                 0.03 
               
               
                 3:20:17 PM 
                 44.2714 
                 174.218 
                 71.4021 
                 0.03 
               
               
                 3:20:27 PM 
                 44.1389 
                 173.541 
                 61.8197 
                 0.03 
               
               
                 3:20:37 PM 
                 43.9804 
                 172.353 
                 65.3808 
                 0.03 
               
               
                 3:20:47 PM 
                 43.9596 
                 172.823 
                 75.4319 
                 0.45 
               
               
                 3:20:57 PM 
                 43.8511 
                 173.112 
                 81.5016 
                 4.65 
               
               
                 3:21:07 PM 
                 43.8667 
                 173.343 
                 88.7164 
                 5.76 
               
               
                 3:21:17 PM 
                 43.8511 
                 173.674 
                 138.142 
                 5.57 
               
               
                 3:21:27 PM 
                 43.8433 
                 173.959 
                 146.358 
                 5.96 
               
               
                 3:21:37 PM 
                 43.8667 
                 174.182 
                 149.282 
                 5.31 
               
               
                 3:21:47 PM 
                 43.8979 
                 174.5 
                 150.273 
                 5.76 
               
               
                 3:21:57 PM 
                 43.9758 
                 174.561 
                 150.717 
                 6.08 
               
               
                 3:22:07 PM 
                 43.9836 
                 174.466 
                 151.014 
                 5.63 
               
               
                 3:22:17 PM 
                 44.0304 
                 174.594 
                 151.346 
                 4.22 
               
               
                 3:22:27 PM 
                 44.0772 
                 174.635 
                 139.776 
                 3.73 
               
               
                 3:22:37 PM 
                 44.0694 
                 174.703 
                 124.316 
                 4.40 
               
               
                 3:22:47 PM 
                 44.0304 
                 174.79 
                 124.216 
                 4.73 
               
               
                 3:22:57 PM 
                 43.9914 
                 174.703 
                 126.607 
                 4.47 
               
               
                 3:23:07 PM 
                 43.9914 
                 174.689 
                 126.919 
                 4.56 
               
               
                 3:23:17 PM 
                 44.007 
                 174.689 
                 127.792 
                 4.28 
               
               
                 3:23:27 PM 
                 44.0304 
                 174.676 
                 130.123 
                 4.98 
               
               
                 3:23:37 PM 
                 44.007 
                 174.723 
                 131.121 
                 4.50 
               
               
                 3:23:47 PM 
                 44.0304 
                 174.696 
                 132.166 
                 5.07 
               
               
                 3:23:57 PM 
                 44.0227 
                 174.729 
                 134.944 
                 5.15 
               
               
                 3:24:07 PM 
                 43.9838 
                 174.675 
                 135.331 
                 0.03 
               
               
                 3:24:17 PM 
                 43.8045 
                 174.587 
                 107.9 
                 0.03 
               
               
                 3:24:27 PM 
                 43.6485 
                 174.181 
                 55.0661 
                 0.03 
               
               
                 3:24:37 PM 
                 43.5939 
                 174.235 
                 47.9435 
                 1.58 
               
               
                 3:24:47 PM 
                 43.5159 
                 172.557 
                 55.5128 
                 2.60 
               
               
                 3:24:57 PM 
                 43.4613 
                 172.855 
                 74.6183 
                 1.94 
               
               
                 3:25:07 PM 
                 43.4223 
                 173.207 
                 74.5957 
                 1.31 
               
               
                 3:25:17 PM 
                 43.3989 
                 173.098 
                 74.4224 
                 2.68 
               
               
                 3:25:27 PM 
                 43.3911 
                 172.882 
                 78.4307 
                 4.91 
               
               
                 3:25:37 PM 
                 43.4067 
                 173.173 
                 110.219 
                 5.20 
               
               
                 3:25:47 PM 
                 43.4613 
                 173.491 
                 129.762 
                 5.08 
               
               
                 3:25:57 PM 
                 43.4691 
                 173.64 
                 133.013 
                 5.20 
               
               
                 3:26:07 PM 
                 43.5003 
                 173.87 
                 133.852 
                 5.08 
               
               
                 3:26:17 PM 
                 43.5471 
                 174.127 
                 134.282 
                 5.31 
               
               
                 3:26:27 PM 
                 43.6173 
                 174.093 
                 134.627 
                 5.25 
               
               
                 3:26:37 PM 
                 43.5939 
                 174.033 
                 134.951 
                 5.44 
               
               
                 3:26:47 PM 
                 43.5861 
                 174.107 
                 135.036 
                 0.60 
               
               
                 3:26:57 PM 
                 43.5401 
                 173.962 
                 98.6244 
                 0.03 
               
               
                 3:27:07 PM 
                 43.4387 
                 173.82 
                 56.8212 
                 0.03 
               
               
                 3:27:17 PM 
                 43.3997 
                 173.482 
                 48.0761 
                 0.03 
               
               
                 3:27:27 PM 
                 43.3451 
                 173.313 
                 45.628 
                 0.03 
               
               
                 3:27:38 PM 
                 43.2593 
                 173.164 
                 47.3618 
                 0.03 
               
               
                 3:27:48 PM 
                 43.2359 
                 171.741 
                 55.3284 
                 0.03 
               
               
                 3:27:58 PM 
                 43.2124 
                 171.476 
                 59.6308 
                 0.03 
               
               
                 3:28:08 PM 
                 43.1968 
                 171.32 
                 56.2213 
                 0.03 
               
               
                 3:28:18 PM 
                 43.1344 
                 171.144 
                 48.1149 
                 0.03 
               
               
                 3:28:28 PM 
                 43.111 
                 170.981 
                 44.8494 
                 0.03 
               
               
                 3:28:38 PM 
                 43.0564 
                 170.927 
                 44.0781 
                 0.03 
               
               
                 3:28:48 PM 
                 43.0252 
                 170.757 
                 43.8598 
                 0.03 
               
               
                 3:28:58 PM 
                 42.994 
                 170.52 
                 44.4911 
                 0.03 
               
               
                 3:29:08 PM 
                 42.955 
                 170.18 
                 49.4645 
                 0.03 
               
               
                 3:29:18 PM 
                 42.9471 
                 169.895 
                 50.7347 
                 0.03 
               
               
                 3:29:28 PM 
                 42.9003 
                 169.691 
                 51.0674 
                 0.03 
               
               
                 3:29:38 PM 
                 42.9342 
                 169.374 
                 51.2093 
                 0.03 
               
               
                 3:29:48 PM 
                 42.8938 
                 169.229 
                 51.1929 
                 0.03 
               
               
                 3:29:58 PM 
                 42.9016 
                 168.963 
                 51.1233 
                 4.77 
               
               
                 3:30:08 PM 
                 42.9407 
                 170.139 
                 90.075 
                 4.94 
               
               
                 3:30:18 PM 
                 42.9407 
                 170.703 
                 123.685 
                 5.31 
               
               
                 3:30:28 PM 
                 42.9641 
                 171.347 
                 129.39 
                 5.37 
               
               
                 3:30:38 PM 
                 43.0187 
                 172.012 
                 131.364 
                 4.60 
               
               
                 3:30:48 PM 
                 43.0655 
                 172.52 
                 130.601 
                 4.84 
               
               
                 3:30:58 PM 
                 43.0967 
                 172.947 
                 130.601 
                 5.21 
               
               
                 3:31:08 PM 
                 43.1514 
                 172.906 
                 130.983 
                 5.20 
               
               
                 3:31:18 PM 
                 43.1358 
                 172.798 
                 131.315 
                 4.88 
               
               
                 3:31:28 PM 
                 43.1748 
                 173.17 
                 131.647 
                 4.61 
               
               
                 3:31:38 PM 
                 43.206 
                 173.698 
                 131.704 
                 5.07 
               
               
                 3:31:48 PM 
                 43.2372 
                 174.064 
                 131.739 
                 4.94 
               
               
                 3:31:58 PM 
                 43.2684 
                 174.287 
                 131.986 
                 4.51 
               
               
                 3:32:08 PM 
                 43.3152 
                 174.402 
                 132.276 
                 5.23 
               
               
                 3:32:18 PM 
                 43.323 
                 174.442 
                 132.445 
                 5.08 
               
               
                 3:32:28 PM 
                 43.3698 
                 174.524 
                 132.636 
                 4.23 
               
               
                 3:32:38 PM 
                 43.4322 
                 174.483 
                 132.706 
                 5.11 
               
               
                 3:32:48 PM 
                 43.4406 
                 174.515 
                 132.663 
                 4.55 
               
               
                 3:32:58 PM 
                 43.4874 
                 174.488 
                 132.536 
                 4.58 
               
               
                 3:33:08 PM 
                 43.503 
                 174.508 
                 132.536 
                 5.14 
               
               
                 3:33:18 PM 
                 43.5186 
                 174.508 
                 132.472 
                 4.33 
               
               
                 3:33:28 PM 
                 43.5498 
                 174.535 
                 124.097 
                 4.83 
               
               
                 3:33:38 PM 
                 43.5654 
                 174.596 
                 136.853 
                 5.53 
               
               
                 3:33:48 PM 
                 43.5888 
                 174.657 
                 143.873 
                 5.07 
               
               
                 3:33:58 PM 
                 43.6512 
                 174.623 
                 146.047 
                 5.39 
               
               
                 3:34:08 PM 
                 43.6512 
                 174.664 
                 146.339 
                 5.77 
               
               
                 3:34:18 PM 
                 43.6902 
                 174.731 
                 146.443 
                 5.84 
               
               
                 3:34:28 PM 
                 43.7447 
                 174.657 
                 146.589 
                 5.72 
               
               
                 3:34:38 PM 
                 43.7993 
                 174.738 
                 146.624 
                 5.65 
               
               
                 3:34:48 PM 
                 43.8461 
                 174.779 
                 148.618 
                 5.48 
               
               
                 3:34:58 PM 
                 43.9007 
                 174.846 
                 152.621 
                 5.61 
               
               
                 3:35:08 PM 
                 43.9163 
                 174.826 
                 153.16 
                 5.58 
               
               
                 3:35:18 PM 
                 43.9708 
                 174.738 
                 153.36 
                 6.05 
               
               
                 3:35:28 PM 
                 44.002 
                 174.813 
                 153.395 
                 5.26 
               
               
                 3:35:38 PM 
                 44.0569 
                 174.818 
                 153.463 
                 5.28 
               
               
                 3:35:48 PM 
                 44.1192 
                 174.872 
                 153.47 
                 5.98 
               
               
                 3:35:58 PM 
                 44.1816 
                 174.859 
                 153.504 
                 5.84 
               
               
                 3:36:08 PM 
                 44.2544 
                 174.895 
                 153.514 
                 4.46 
               
               
                 3:36:18 PM 
                 44.2934 
                 174.875 
                 151.779 
                 4.84 
               
               
                 3:36:28 PM 
                 44.309 
                 174.712 
                 139.422 
                 3.03 
               
               
                 3:36:38 PM 
                 44.3012 
                 174.679 
                 116.732 
                 2.69 
               
               
                 3:36:48 PM 
                 44.2778 
                 174.374 
                 108.42 
                 2.70 
               
               
                 3:36:58 PM 
                 44.2154 
                 174.178 
                 101.754 
                 0.76 
               
               
                 3:37:08 PM 
                 44.1843 
                 174.023 
                 99.4504 
                 1.08 
               
               
                 3:37:18 PM 
                 44.1609 
                 173.671 
                 95.4277 
                 1.91 
               
               
                 3:37:29 PM 
                 44.1297 
                 173.461 
                 94.3308 
                 0.03 
               
               
                 3:37:39 PM 
                 44.0362 
                 173.386 
                 88.8547 
                 0.03 
               
               
                 3:37:49 PM 
                 43.927 
                 172.953 
                 75.2487 
                 0.03 
               
               
                 3:37:59 PM 
                 43.8257 
                 172.52 
                 71.861 
                 0.03 
               
               
                 3:38:09 PM 
                 43.7399 
                 172.255 
                 70.7566 
                 0.03 
               
               
                 3:38:19 PM 
                 43.7009 
                 172.086 
                 70.1736 
                 0.03 
               
               
                 3:38:29 PM 
                 43.6619 
                 171.889 
                 69.8857 
                 0.03 
               
               
                 3:38:39 PM 
                 43.6235 
                 171.752 
                 66.6978 
                 0.03 
               
               
                 3:38:49 PM 
                 43.5377 
                 171.508 
                 53.2521 
                 0.03 
               
               
                 3:38:59 PM 
                 43.5221 
                 171.379 
                 48.2911 
                 0.03 
               
               
                 3:39:09 PM 
                 43.5065 
                 171.148 
                 46.4735 
                 0.03 
               
               
                 3:39:19 PM 
                 43.4909 
                 171.107 
                 45.6879 
                 0.03 
               
               
                 3:39:29 PM 
                 43.4519 
                 171.012 
                 45.1586 
                 0.03 
               
               
                 3:39:39 PM 
                 43.3739 
                 170.741 
                 44.9873 
                 0.03 
               
               
                 3:39:49 PM 
                 43.3115 
                 170.66 
                 44.6913 
                 0.03 
               
               
                 3:39:59 PM 
                 43.2647 
                 170.361 
                 44.6368 
                 0.03 
               
               
                 3:40:09 PM 
                 43.2413 
                 170.252 
                 44.5822 
                 0.03 
               
               
                 3:40:19 PM 
                 43.2023 
                 170.089 
                 44.5433 
                 0.03 
               
               
                 3:40:29 PM 
                 43.1867 
                 169.695 
                 47.2817 
                 0.03 
               
               
                 3:40:39 PM 
                 43.1477 
                 169.152 
                 49.6559 
                 0.03 
               
               
                 3:40:49 PM 
                 43.1817 
                 168.801 
                 50.65 
                 0.03 
               
               
                 3:40:59 PM 
                 43.1895 
                 168.474 
                 50.7661 
                 0.03 
               
               
                 3:41:09 PM 
                 43.1505 
                 168.188 
                 51.1221 
                 0.03 
               
               
                 3:41:19 PM 
                 43.1165 
                 167.805 
                 51.127 
                 0.03 
               
               
                 3:41:29 PM 
                 43.1583 
                 167.569 
                 51.1453 
                 0.03 
               
               
                 3:41:39 PM 
                 43.1506 
                 166.683 
                 51.1221 
                 5.70 
               
               
                 3:41:49 PM 
                 43.1896 
                 168.556 
                 93.6402 
                 5.33 
               
               
                 3:41:59 PM 
                 43.2442 
                 169.31 
                 137.937 
                 5.51 
               
               
                 3:42:09 PM 
                 43.252 
                 170.343 
                 146.154 
                 6.10 
               
               
                 3:42:19 PM 
                 43.3222 
                 171.076 
                 148.315 
                 6.05 
               
               
                 3:42:29 PM 
                 43.3768 
                 171.93 
                 149.619 
                 6.08 
               
               
                 3:42:39 PM 
                 43.4002 
                 171.869 
                 150.679 
                 5.98 
               
               
                 3:42:49 PM 
                 43.4782 
                 171.883 
                 151.517 
                 5.71 
               
               
                 3:42:59 PM 
                 43.5484 
                 172.622 
                 151.994 
                 6.04 
               
               
                 3:43:09 PM 
                 43.6264 
                 173.312 
                 152.056 
                 5.45 
               
               
                 3:43:19 PM 
                 43.681 
                 173.387 
                 151.635 
                 0.03 
               
               
                 3:43:29 PM 
                 43.5328 
                 173.238 
                 76.0342 
                 0.03 
               
               
                 3:43:39 PM 
                 43.4938 
                 172.716 
                 51.1144 
                 0.03 
               
               
                 3:43:49 PM 
                 43.4626 
                 172.628 
                 46.7018 
                 0.03 
               
               
                 3:43:59 PM 
                 43.2832 
                 172.649 
                 45.9164 
                 0.03 
               
               
                 3:44:09 PM 
                 43.1896 
                 170.696 
                 54.4813 
                 0.03 
               
               
                 3:44:19 PM 
                 43.1194 
                 170.316 
                 63.2646 
                 0.03 
               
               
                 3:44:29 PM 
                 43.0884 
                 170.621 
                 62.9592 
                 0.03 
               
               
                 3:44:39 PM 
                 43.0337 
                 171.211 
                 60.8798 
                 0.03 
               
               
                 3:44:49 PM 
                 43.0259 
                 171.116 
                 60.5047 
                 0.03 
               
               
                 3:44:59 PM 
                 42.9713 
                 170.98 
                 57.6287 
                 0.03 
               
               
                 3:45:09 PM 
                 42.8933 
                 170.919 
                 56.1526 
                 0.03 
               
               
                 3:45:19 PM 
                 42.8152 
                 170.668 
                 55.9295 
                 0.03 
               
               
                 3:45:29 PM 
                 42.7528 
                 170.315 
                 55.7755 
                 0.03 
               
               
                 3:45:39 PM 
                 42.7294 
                 170.01 
                 54.5354 
                 0.03 
               
               
                 3:45:49 PM 
                 42.7684 
                 170.566 
                 54.7897 
                 6.72 
               
               
                 3:45:59 PM 
                 42.7918 
                 171.53 
                 140.362 
                 6.67 
               
               
                 3:46:09 PM 
                 42.8337 
                 172.231 
                 163.43 
                 7.06 
               
               
                 3:46:20 PM 
                 42.8337 
                 172.705 
                 168.136 
                 6.64 
               
               
                 3:46:30 PM 
                 42.8493 
                 172.766 
                 167.121 
                 0.03 
               
               
                 3:46:40 PM 
                 43.1146 
                 172.664 
                 166.42 
                 0.03 
               
               
                 3:46:50 PM 
                 43.3019 
                 172.522 
                 134.064 
                 0.03 
               
               
                 3:47:00 PM 
                 43.2083 
                 172.17 
                 64.1372 
                 0.03 
               
               
                 3:47:10 PM 
                 43.5281 
                 171.919 
                 65.7372 
                 0.03 
               
               
                 3:47:20 PM 
                 43.5281 
                 171.817 
                 76.383 
                 0.03 
               
               
                 3:47:30 PM 
                 43.5437 
                 171.614 
                 83.1848 
                 0.03 
               
               
                 3:47:40 PM 
                 43.5671 
                 171.485 
                 84.8249 
                 0.03 
               
               
                 3:47:50 PM 
                 43.5671 
                 171.363 
                 85.5247 
                 0.03 
               
               
                   
               
             
          
         
       
     
         [0123]      FIG. 20  depicts a diagrammatic or schematic diagram of the test from which the above data were derived. In the test represented by the data of Table 1 and  FIGS. 19A-G , and as schematically depicted in  FIG. 20 , a cold water line  910  from cold water supply  911  was coupled to a mixed water inlet  912 , a hot water line  914  from hot water supply  913  was coupled to mixed water inlet  912 . A diffuser  916  was coupled to mixed water inlet  912  so that hot and cold water flowed through mixed water inlet  912  and into diffuser  916 . A mixed water outlet  918  was coupled to diffuser  916  so that water flowing from the diffuser passed through outlet  918  toward a drain (not shown). Thermocouples  920 ,  922 ,  924 , were coupled to cold inlet, hot inlet, and mixed fluid outlet lines respectively to measure the temperature of the water flowing through each. A pressure sensor  926  was positioned in the hot water line to sense the pressure in the hot water. Thermocouples  920 ,  922 ,  924  and sensor  926  were coupled to computer  928  which recorded the data from each thermocouple, as depicted in Table 1 above. Valves  930  were positioned in each of the water lines to shut off or throttle flow of the hot, cold, and/or mixed water as necessary. 
         [0124]    To simulate different stagnant hot fluid line temperatures that might be encountered in different settings, a starting mixed water temperature was arrived at by adjusting the hot  930   b  and cold  930   a  valves until a desired temperature was reached. For example,  FIG. 19A  shows a starting mixed fluid temperature of about 85 degrees F. Once the desired starting temperature for the mixed water was achieved, all flow was simultaneously shut off. Then, the hot water valve  930   b  was opened full-open to simulate the hot water displacing the stagnant water in the hot water line. Mixed water temperature in the mixed water outlet line was recorded via thermocouple  924  (shown in the fourth column). Cold and hot water temperatures were recorded via thermocouples  920  and  922  in the cold and hot water lines respectively, those temperatures shown in the second and third columns respectively. The time of day each reading was made is indicated in the first column, each entry separated from the prior entry by ten seconds. The pressure, represented in the fifth column, was recorded in the hot water line, is shown in pounds per square inch gauge (psig), and serves to indicate when the hot water was opened to the full-open position. 
         [0125]    Thermocouple  920  was about 6 feet away from the point where cold inlet line  910  connects to mixed inlet line  912 , and thermocouple  922  was about 6 feet away from the point where hot inlet line  914  connects to mixed inlet line  912  (each distance of about 6 feet including about 2 feet of rubber hose). Thermocouple  924  and sensor  926  were about 5 feet away (about 3 feet of which was rubber hose) from the point where diffuser  916  connects to mixed outlet line  918 . 
         [0126]      FIGS. 19A  through G represent graphically certain data from Table 1. Data were taken at ten (10) second intervals. The mixed water temperature is observed to increase to a local maximum in each of the graphs depicted in  FIGS. 19A  through G. The starting temperature of the mixed water was controlled by adjusting the hot valve while leaving the cold valve in the full-open position to achieve a desired starting mixed water temperature. The gradual increase in mixed water temperature, compared to plug flow through a single pass of pipe resulting in a nearly immediate jump to hot water of equal temperature with the temperature of the hot water in the water heater tank, demonstrates the effects of the diffuser. 
         [0127]    Although this invention has been described and illustrated in detail with reference to certain illustrative embodiments, variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.