Abstract:
Applicant discloses a thermally actuated valve having a housing, a resilient seat, a thermally conductive piston, a spring fluid seal, and a working material. The housing defines an inlet and an outlet and has two chambers. The seat is adjacent the inlet and the piston is adapted to move towards the seat when a working fluid in the housing warms and expands and away from the seat when a working fluid in the housing cools. By moving away from the seat, fluid flow through the valve is generated. In one application, Applicant&#39;s valve acts as a freeze prevention device. In another application, Applicant&#39;s valve is used to cool a source of water.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to, the benefit of, and incorporates by reference, U.S. Provisional Patent Application No. 61/828,474, filed May 13, 2013. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Temperature controlled valve for water systems, including water well and water softener freeze protection, as well as other system water flow control. 
       BACKGROUND OF THE INVENTION 
       [0003]    Water well and water softener systems use pressurized water in pipes or other elements that are sometimes exposed to cold temperatures. Freeze protection in the past has typically utilized wrapping exposed elements with electrical heat tape or insulation or a combination of both methods. While these solutions are often satisfactory for most conditions, there exists a need for a non-electrical, non-passive system that engages pressurized elements of water supply assemblies for actively preventing freeze-up by temperature, with the use of the pressurized systems water, to purge the chilled water and subsequently, and as a direct result of purging, replace with warmer water. This action prevents the devices from freezing. There is also the need for flow control in water systems wherein water cooler than ambient is needed downstream of a water supply. 
       SUMMARY OF THE INVENTION 
       [0004]    A water carrying pressure bearing system comprising a source of water pressure is provided. Water bearing lines or water bearing containers are sometimes exposed to external air temperature fluctuations or ambient water conditions. Downstream of the source of water, freeze protection is provided. Protected system elements are in fluid communication with a water bearing line and the source of water pressure. In the water bearing line, there is a working fluid containing a phase change activated purge valve, the working fluid typically having a freezing point above 32° F., the valve in fluid communication with the water bearing line. In one embodiment, the valve is biased to a normally closed position at temperatures above the freezing point of the working fluid. The valve opens as the working fluid contracts and freezes. The working fluid may be, in one embodiment, selected from fluids with freezing points being in the range of about 32° F. to about 50° F. or preferably about 34° F. to 45° F. The valve may have an outlet engaged therewith to carry away water received therein when the valve opens responsive to cooling air on an air sensing portion. The valve may be moderated by a water temperature sensing side. The protected elements, in three embodiments, comprise a water softener controller valve, a water trough, and a pressure switch for any number of uses or systems. 
         [0005]    In a first embodiment of several, Applicant provides an active, non-electrical, air and water temperature responsive purge valve downstream of a well water pump and upstream of a pressure sensing switch in a water distribution system, which may include a water well and pressurized water tank. In a second embodiment, Applicant provides a similar valve on a pressure line downstream of a water softener. Fluid flow directly from the well pump, tank or other pressure source may be about 56° F. to 65° F., no matter the ambient temperatures. Purge valves in both embodiments are typically located in outside air, where they may be subject to contact with both the water in the system and the outside air. The valve contains a chamber having a material selected from materials which freeze between the temperatures of about 32° F. and 50° F., most preferably about 41.5° F. In doing so, the freezing working material contracts to allow a spring biased valve to open on a water pressure line, which valve then dumps or bypasses fluid from a high side (which may be well water pressure tank pressure) to a low side bypass, which may be ambient pressure. In doing so, pressure relief in the system at a temperature above the freezing point of water, generates fluid flow from the well and/or pressure tank or other source, thereby preventing freeze-up. In a preferred embodiment of Applicant&#39;s valve, there is a range of cross-sectional area ratios between water contacting elements of the valve and air contacting elements of the valve. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIGS. 1 and 2  are schematic illustrations of Applicant&#39;s novel valve as used in a water well system and a water softener system. 
           [0007]      FIG. 1A  is a schematic illustration of details of the relationship between a mechanical purge valve and a pressure switch. 
           [0008]      FIGS. 1B and 1C  are illustrations of an electrical embodiment of Applicant&#39;s purge valve for use in close proximity to a pressure switch. 
           [0009]      FIGS. 2A and 2B  illustrate cross-sectional areas of a first, water contacting portion and a second, air contacting portion, respectively, of Applicant&#39;s novel valve. 
           [0010]      FIGS. 3 and 4  illustrate side cross-sectional views of an example embodiment of Applicant&#39;s novel valve in a closed and open position, respectively. 
           [0011]      FIG. 4A  is a cross-sectional detail view of the multi O-ring seal of  FIG. 4  showing the lubricant used therewith. 
           [0012]      FIG. 5  is a side elevation cutaway of the purge valve (open). 
           [0013]      FIGS. 6 and 6A  illustrate the use of a remote purge port for pipe downstream of the purge valve. 
           [0014]      FIGS. 7A ,  7 B, and  7 C provide cross-sectional cutaway views of another example embodiment of Applicant&#39;s present mechanical purge valve in three conditions:  FIG. 7A , warming a water source responsive to cool ambient temperatures;  FIG. 7B , cooling a water source responsive to warm ambient temperatures; and  FIG. 7C , valve closed condition, the valve not affecting the flow of water through the system. 
           [0015]      FIG. 8  is a partially schematic view of a cattle trough water flow system that is adapted to use Applicant&#39;s novel valve in any of the embodiments illustrated. 
           [0016]      FIG. 9  is a cross-sectional view of a valve showing a method of calibrating Applicant&#39;s mechanical valve so it opens and closes at the proper temperatures. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]      FIG. 1  illustrates Applicant&#39;s valve  10  as part of a water well assembly  100  and  FIG. 2  illustrates Applicant&#39;s valve as part of a water softener assembly  200 .  FIGS. 3 ,  4 , and  4 A illustrate details of an example of valve  10  having a first body portion  30  and a second body portion  32 , with a sealing area  33  therebetween, and a valve seat  34 . A temperature/pressure responsive piston  38  opens a bypass purge or port  36 , and controls the flow of water through the bypass port  36  when the temperature drops below a set point, such as in the range of about 32° F. to 50° F., which set point is typically about 10° above the freezing point of water. Piston  38  is responsive to a change in volume (at phase change) of a working fluid  40 , which working fluid fills a fluid chamber  42  in the first body portion  30  of the valve. When fluid  40  (which is typically not water based) in chamber  42  reaches a point, it will contract as it loses heat and changes phase from a liquid to a solid at the freezing point of the fluid, and will cause piston  38 , biased open by the spring  44 , to retract from seat  34 . This allows water well and/or pressure tank pressurized water to flow through the bypass port  36  and out an outlet or purge port  37 . Further details of Applicant&#39;s novel valve will be set forth after an explanation of its use in the system. 
         [0018]    Turning to  FIG. 1 , it is seen that system  100  may include a water well  112 , such as a domestic or commercial (municipal) water well, which may have a pump  114  (mechanical or electrical), such as submerged pump or any other pump suitably located to draw water from below the ground level of the well. A water supply line  115  provides the water under pressure through a pressure switch  120  control, to a pressurized water tank  116 . Demand from users downstream of pressure tank  116  will allow water to flow out through line  118  to provide their needs. Pressure switch  120  is typically provided somewhere in the system (typically at, or upstream of tank  116 ), responsive to pressure changes in tank  116 , such that below a low set pressure, pump  114  will be activated and provide water to tank  116 , and above a high set pressure, will shut off. 
         [0019]      FIG. 1  illustrates Applicant&#39;s well water well assembly  100  in various downstream water uses of the water from the water well assembly  100 . These uses may include use in a commercial or residential structure  216 , in a cooling tower, such as those known in the art for cooling the hot side of air conditioners  218 , and a livestock animal trough  220 , as set forth in more detail hereinbelow. 
         [0020]    Pressure switch  120  may be of the diaphragm type and when exposed to temperatures near or below 32° F., especially when windy, can freeze up faster than any other part of the well assembly. They then become non-responsive to pressure changes in the system. When this occurs, a pressure drop in the pressure tank will not initiate a signal to start the pump, and the system has failed mechanically and is subject to further freezing and potential damage to equipment. 
         [0021]    Use of Applicant&#39;s purge valve  10  in the system, typically at or upstream of tank  116  and typically close to the pressure switch, will help ensure that under even severe weather conditions, the purge valve, acting independently of the pressure switch, will help prevent freeze-up. 
         [0022]    Applicant&#39;s water well assembly may have a pump which may be a mechanical water pump, such as a mechanical or a sucker rod pump or an electrical pump (or any other suitable pump). It may have a storage tank, which may be a pressurized storage tank, gravity feed storage tank or any suitable water storage tank for receiving water pumped from a domestic, commercial or agricultural water well. Typically, one or more water flow control devices are a part of the water well assembly to control the water pumped as it is used by downstream elements of the water well assembly. 
         [0023]      FIG. 1A  illustrates a schematic detail view showing the manner in which Applicant&#39;s purge valve may be used with a fluid pressure source pressurizing a pressure switch. 
         [0024]    In  FIG. 1A , a pressure switch  120  as known in the art, may include diaphragm  120   a  responsive to water pressure in pressure switch mount pipe  121 , may engage one arm of electrical contacts  120   b  to close or open the contacts and energize/de-energize a remote pump responsive to water pressure in a pressure source and responsive in some embodiments to pressure in a pressure tank as set forth herein. A tee or horizontal member  122  may extend perpendicular to the typically vertical mount pipe  121 . In any case, Applicant&#39;s valve  10  is typically located below the pressure switch  120  and in a manner that it may open and gravity drain, for example, through drain port  37 , fluid from contact with the diaphragm. This will prevent freeze-up from damaging the diaphragm. It will also initiate a pump “on” condition by draining water in the tank. The pump will re-pressurize the system with, typically warmer water which, in turn, will help shut the mechanical purge valve. It will also initiate an “on” condition, by draining water from the pressure tank, which forces the pressure switch to turn the water well pump on, and refill the tank and piping with warmer water. 
         [0025]      FIG. 1A  illustrates that, in one embodiment, valve  10  is usually within a minimum distance (measured by fluid pathway) of about ¼ inch to about 12 inches from the diaphragm of the pressure switch. This will help protect and prevent freeze-up of the pressure switch. 
         [0026]      FIGS. 1B and 1C  illustrate an alternate preferred embodiment of Applicant&#39;s system. Wherein the other systems set forth herein use a mechanical purge valve  10 , it is noted that, in conjunction with a pressure switch, a solenoid valve  126  powered by a power circuit  127  may be used in close proximity to the pressure switch so that it may drain from a gravity fed outlet  128 , water or other fluid at a pressure source  121 . That is to say, instead of a mechanical valve  10 , a solenoid valve  126  may operate with a circuit which includes power  123  (battery, DC, AC, solar or any suitable source) and a thermostat switch  130 . Thermostat switch  130  will typically be set for the same approximate range as the mechanical purge valve, that is closing at least several degrees above freezing and opening solenoid valve  126  to allow fluid to drain before freeze-up at the pressure switch. As seen in  FIG. 1C , thermostat switch  130  (or a sensor therefor) may be placed adjacent or on elements, metallic or non-metallic, downstream of solenoid valve  126 . At position 2 or 3 as seen in  FIG. 1C , when warmer water from a well, for example, flows through an open the solenoid valve, thermostat switch  130  may open causing the solenoid valve to close, thus re-pressurizing the pressure switch with, typically, warmer water. Position 1 locates switch  130  in air, while positions 2 and 3 are both water and air temperature exposures. 
         [0027]    Further details of the valve may be appreciated with reference to  FIG. 3 . First portion  30  may be referred to as “air exposed” portion and contains an external surface, typically cylindrical and constructed of brass or other suitable metal, which also may be referred to as the air temperature sensing portion of valve  10 . A second portion  32  has an interior that may be subject to the presence of stationary water (or empty) when the valve is closed and which carries water in an open or “protect” mode and is subject to the temperature bias of the purged water as it is discharged. 
         [0028]    In a situation where the air temperature cools suddenly, for example, with the passage of a sudden cold front, first portion  30  will cool more quickly, subject as it is to exposure with the air, especially moving air, and second portion  32  will lag, subject to the water or proximity to system water and the contact with the water within (valve open) body portion  32  or proximate (valve closed) to body portion  32 . Water is known to moderate temperature changes (it has a much higher specific heat than the material, typically brass or other suitable metal, of which the valve body is made). Warm water within portion  32  will typically provide warmth to portion  32 , which by conduction will provide some heat to portion  30  as it drops below the set point. Thus, portion  32  will have the effect of moderating air caused temperature changes of portion  30 , so that especially with sudden changes of air temperature, sufficient heat may flow from portion  32  to  30  to moderate and prevent too quick a freeze-up of working fluid  40  (and thus a draining of water from the system). 
         [0029]      FIGS. 3 and 4  illustrate valve  10  in a closed and open position irrespectively. Working fluid chamber  42  is sealed at a first end by removable threaded cap  20 . Cap  20  may use an O-ring  22  on a shoulder thereof to tightly seal working fluid  40  in fluid chamber  42 . Typically, the working fluid will be sealed into the chamber when in its liquid phase. The set point is calibrated by advancing the plug until the nose  38   a  of piston  38  is sealed in seat  34  which, in one embodiment, is an O-ring (see also  FIG. 9 ). Spring  44  biases valve piston to the open position (see  FIG. 4 ). However, fluid pressure of working fluid  40  in fluid chamber  42  holds the valve in the seated or closed position at temperatures above the set point. At these temperatures, the working fluid will expand slightly (compared to set point) to maintain a good seat, especially in an elastomeric seat, such as O-ring valve seat  34 . However, as the air temperature cools through the set point, the working fluid will begin to undergo phase change and contract, thereby temperature proportionally opening valve as in  FIG. 4 . This will allow water to pass into the valve and out the port, utilizing the ambient pressure PW (see  FIG. 3 ), which pressure is generated by the pressure tank and/or pump. 
         [0030]      FIGS. 4 and 4A  illustrate the use of an anti-seize lubricant  33   c , which has a freezing point less than water. These lubricants may be used to fill in, around, and between the O-rings that separate the chamber containing the working fluid and the chamber through which purged fluid, typically water, will pass out of when the purge valve is opened. Tolerances between the piston and the body may be plus or minus 0.001 inch. It is seen the lubricant tends to be held in between the spaces that separate adjacent O-rings and the piston walls where they contact the body. 
         [0031]    When the valve opens, water will be drawn through the channels of portion  32  and out the drain port to dump onto the ground, to recycle in the well (as illustrated in  FIG. 1 ) or for other suitable disposal. This water will typically be warmer than air temperature and will warm the surrounding material of portion  32 . Heat by conduction will flow to portion  30 . 
         [0032]    Working fluid  40 , in certain embodiments, will undergo a phase change at about 41.5° F. (5.5° C.), which is approximately 10 degrees above the Fahrenheit freezing point for pure water. One such material is an alkane known as Tetradecane (C 14 H 30 ), which undergoes a volumetric contraction of about 20% at the freezing/melting point (range 39-43° F.) as measured from a liquid phase to a solid phase. Preferably, working fluid  40  would undergo a phase change from liquid to solid contracting at the phase change, which freezing (melting) point is in the range of about 6° to about 18° F. above the freezing point of water in one embodiment. 
         [0033]    In some embodiments, cross-sectional area α of portion  32  is typically larger than cross-sectional area β of portion  30  (see  FIGS. 2A and 2B ). The metallic elements defining the body of the valve may, in particular embodiments, be brass (specific heat of approximately 0.1). The range of the larger area, that is, the cross-sectional area of portion  32  which contacts the water may be in the range of 1.2 to 4 times the cross-sectioned area of the air sensitive portion. 
         [0034]    Turning to  FIGS. 2 ,  6 , and  6 A, a water softener system  200  is illustrated, which has a water softener pressurized from a pressurized water source  210 , which may be water well or water pressure tank or city water.  FIGS. 6 and 6A  illustrate Applicant&#39;s use of valve  10  on a water softener assembly  200  downstream of a water softener tank  214 . Water from tank  214  is pressurized, valve  10  is typically exposed to ambient conditions. Pipes  212  downstream of resin tank  214 , and other elements of the system may be exposed to cold air, as in a garage, shed or outside of a building. As such, they may benefit from use of Applicant&#39;s valve  10 , which may be “teed” or otherwise installed into a water pressure bearing outlet, such as soft water outlet line  211 , that is subject to cold temperatures. In the same fashion as set forth with the water well assembly  100 , cold air temperatures will generate purging of the pressurized lines, which flow will maintain the circuit in a flow condition, for a period of time, to prevent freeze-up. The use of Applicant&#39;s valve is an alternative to leaving faucets on inside the house (so as to keep water flowing in system), which can waste water if ambient temperatures are above freezing and may let pipes freeze if the faucet discharge is less than what is needed for very cold temperatures. The use of Applicant&#39;s valve  10  in either assembly will reduce such water wastage, while preventing the assembly from freezing. 
         [0035]      FIG. 5  illustrates the use of a vacuum break  46  in a threaded drain fitting  47 , which will help prevent siphoning when the removed end of drain tube  48  has water in it. Vacuum break  46  will also provide a water outlet, should any portions of drain line  48  freeze up. Drain tubes  48  are typically placed so that the removed end thereof is adjacent to a drain or goes back into the well. 
         [0036]      FIG. 5  also illustrates the use of a sleeve or jacket  50 , which is typically shaped with an open end  52  and a body  54 , and a closed end  55 , that will slip on and snugly engage the exterior portion  30  to act as a shield and insulation from the possibilities of wind, sleet, snow, ice and/or their accumulation, from affecting the air temperature sensitive portion of the device. Such an insulation jacket  50  may be made from 1/10 inch pliable plastic or suitable material typically with a thermal conductivity less than metal, or may be an air gap. 
         [0037]    Working fluid  40  is sealed in fluid chamber  42  by cap  20  at one end and sealing area  33 , such as multiple O-rings and grooves, which O-rings are urged against the outer wall of piston  38 . One system of O-rings or other elastic material that has proved to be an effective seal to maintain the working fluid sealed in and to resist the pressure generated by expansion of the working fluid may be found in U.S. patent application Ser. No. 11/275,134, which is incorporated herein by reference. 
         [0038]    The purge valve may be placed on a water well close to the pressure switch, approximately ¼″ to 12″ from the pressure switch in certain embodiments. The purge valve may be placed on or near the water softener control box or downstream of the water softener. In general, Applicant&#39;s novel purge valve may be used anywhere on any system where there is a need to prevent freeze-up of pipes. 
         [0039]    Turning to  FIGS. 3 ,  4 , and  5 , basically, the following summarizes some of the structure and functionality of the valve: 
         [0040]    First body portion  30 :
       Cylindrical, typically metallic, defines an inner chamber   External surface exposed to ambient air; internal containing chamber  42  which contains the working fluid and removed end  38   b  of piston  38     Sealing plug or cap  20  for sealing working fluid and pressure calibration (typically screw)   Spring  44  to bias “open”   Optional jacket or sleeve (see  FIG. 5 ) for exterior of metallic cylinder       
 
         [0046]    Second body portion  32 :
       May take any external or internal configuration within an internal water cavity/chamber  31     Chamber  31  bordered longitudinally with sealing area (see below), and bypass purge port  36 , and also containing a vertical trending drain port  37     Metallic heat flow path between (among) T 1  of water in chamber  31 , T 2  in cylinder (working fluid  40 ) first body portion  30 , and T 3  (air) on exterior surface of second body portion  32  (see  FIG. 4 )       
 
         [0050]    Sealing area  33 , located longitudinally between body portions  30  and  32  (see  FIG. 4 )
       Multiple seals adapted to withstand pressure in system   Seals on both sides of a leak vent  39  (prevent leakage) typically lubricant filled (prevents moisture and debris accumulation)   O-rings on working fluid side  33   a  prevent leakage of the working fluid   O-rings on water side  33   b  prevents leakage of water into the leak vent  39     Use of an anti-seize/lubricant compound  33   c  ( FIG. 4A ), on and around the O-rings is preferably food/drug grade       
 
         [0056]      FIG. 3  shows the valve in the closed position. However, the valve in the closed position may have the nose of the piston past the valve seat, that is to the right of the position of the nose with respect to the valve seat as seen in FIG.  3 —such that in a closed position, the O-ring is on the cylindrical body portion of the piston. Regarding the valve seat, it may be an O-ring or other suitable elastomeric material. Regarding the O-rings or other sealing members of portion  33   a  of the sealing system, they are made of an elastomeric material that does not dissolve or react with the working fluid, but provides an effective fluid seal against the body of the piston. An anti-seize/lubricant compound  33   c , such as a food grade silicon-based composition, may be used on and around the piston/O-ring interface.  FIG. 4A  illustrates the use of a low temperature (below the freezing point of water), anti-seize/lubricant compound  33   c  around and between the multiple O-rings that the piston moves over. 
         [0057]    Turning to  FIGS. 5 ,  6 , and  6 A, an optional purge port tube  56  may be provided to remotely locate a removed end  56   a  from a near end  56   b . Near end  56   b  is engaged with a fluid tight couple close to bypass/purge port  36 . When valve  10  is in a closed position, the water softener, well water or other pressure source is in a normal (non-freezing environmental) condition, with the purge valve and all elements thereof “invisible” to the system. However, when the air temperature gets cold outside and first portion  30  communicates a temperature drop by cooling the working fluid to freezing, the valve will then open and drain fluids out through drain port  37  and/or external drain tube  48 . However, because of the use of purge port tube  56  placed in an annulus of pipe DS downstream of valve  10 , the purged fluid is being drawn from the remote removed end  56   a  and, therefore, flows all the way through the annulus between the tube  56  and the inner walls of the DS pipe purging it of cooling water and generating flow, with warmer fluid coming in and preventing freeze-up. Note that removed end  56   a  is typically located past where the pipe annulus enters the interior environment, whether that be just below ground or just inside a wall (see ghosted lines,  FIG. 6A ). In either case, the effect of using purge port tube  56  with removed end  56   a  located in a warmer non-ambient, non-outside air temperature environment is to maintain flow through all of the pipe annulus, even portions downstream of the purge port. Arrows at A in  FIG. 6A  show flow of water when the valve gets cold and opens (piston and seat omitted). 
         [0058]      FIGS. 7A ,  7 B, and  7 C illustrate an alternate embodiment 10′ of Applicant&#39;s valve. Structurally, the difference in the previous embodiment (see, for example,  FIGS. 3 and 4 ) lies in the structure of piston  138 . In the alternate embodiment 10′ of the valve, piston  138  is seen to have a nose  138   a , which has an annular recess  141 . The annular recess is dimensioned such that in a “valve warm” condition ( FIG. 7B ), wherein expansion of the working fluid  40  in chamber  42  has, through expansion responsive to the warm air/ambient water temperatures, pushed the tip of nose  138   a  past O-ring or valve seat  34 , so that annular recess  141  is adjacent to the seat. This is the condition seen in  FIG. 7B  and it may be seen that cool fluid (relative to air temperature) may pass through the space created by the annular recess and out drain port  37  to provide water from the well or storage, which will typically be cooler, to elements downstream of drain port  37 . In this manner, Applicant&#39;s alternate embodiment 10′ acts to provide cool fluid, that is, cooler than air/ambient water temperature, to elements downstream of the valve. Embodiment 10′ will also prevent freeze-up (see  FIG. 7A ) in the manner of valve  10 . 
         [0059]    Applicant has found that, in the summer, livestock, while thirsty and in need of water, are reluctant to drink water from a trough when the water in the trough is too warm. What Applicant provides therefor in an alternate embodiment 10′ of the valve is the ability of the valve piston to “overshoot” the seat and place the annular recess  141  adjacent the seat and allow cooler water from tank  304  to flow into trough  306 . Water in the tank or container  304  is typically cooler in the summer than the surrounding air temperature and the water temperature in the trough, and warmer in the winter than the surrounding air temperature and temperature of the trough, containing as it is, a large warm water received from the ground. 
         [0060]      FIG. 8  illustrates a use of Applicant&#39;s alternate embodiment 10′ in a livestock watering system  300 . Livestock watering systems are used to provide water for livestock in pastures and feedlots and may comprise a water pump  302  engaging a water well  303 . Water pump  302  may be a windmill using a mechanical pump as well known in the art of windmill water pumping. Pump  302  may also be electrical. As illustrated in  FIG. 8 , pump  302  may pump water from well  303  into an elevated tank or other water storage vessel  304  (pressurized or gravity feed) for selectively supplying water to a nearby trough  306 . A conduit  308  is typically provided with Applicant&#39;s valve, in either embodiment, but in the embodiment illustrated  10 ′ at the removed end of conduit  308  and typically beneath water level WL of trough  306 . In some cases, a parallel water feed system  310  may be provided to bring water to trough  306  responsive to water level or float valve  312 . Such float valve  312  controlled water level systems are well known in the art. Applicant&#39;s system provides water to trough  306  separate from and not controlled by the float valve system, if one is present. 
         [0061]    As is seen in  FIG. 8 , first body portion  30  and, in fact, the entire valve  10  or  10 ′ may be submerged below typical water levels in the trough. However, the valve might be in air positioned so it drains water into the trough when opened. As seen in  FIGS. 7A-7C , Applicant&#39;s valve  10 ′ is adapted to provide water that is cooler or warmer than a preselected water temperature range. Typically, the water in the trough has a greater surface area exposed to cold or warm air temperatures than the larger volume of water in storage tank  304  and thus will reach a cooler or warmer temperature sooner than the storage tank in the same air temperature, humidity, and wind conditions. Thus, the valve open condition of  FIG. 7A , which typically occurs at temperatures up to about 18° F. above the freezing point of water, will open and allow relatively warmer water from the tank  304  to enter the trough to prevent ice buildup when the air temperature is cool. When the air gets warm, it can warm the trough water and a condition as seen in  FIG. 7B  can result. This will allow cooler water to flow into the trough. 
         [0062]      FIG. 9  illustrates a threadably removable cap  20  adapted to engage the removed end of second body portion  32 , so as to seal fluid chamber  42 . Cap  20  may have a recessed tool receiving section  20   a  on an exterior surface thereof, and an annular recess  23  on the near end thereof for holding an O-ring  22  (see also  FIG. 3 ). 
         [0063]      FIG. 9  also illustrates a method of calibrating the piston so that it seats and unseats at the proper temperatures. In this method, the valve housing is held vertically in a fixed position and the working material, fluid at room temperature, is used to fill fluid chamber  42 . At this point, the spring will have the piston fully retracted (see  FIG. 4 ). In this method, the valve housing is typically held vertically in a fixed position and the working, fluid at room temperature, is used to fill the fluid chamber  42 . At this point, the spring will have the piston fully retracted from the seat (see  FIG. 4 , for example). The spring is not under compression, the cap is off, and the fluid chamber is fully filled. The cap (which may be self-tapping) is then threaded in with tool  31  until the O-ring  22  contacts the inner walls of the fluid chamber. Further rotation of the cap compresses the working fluid, then moves nose  38  until it is against a dial indicator gauge  315  and/or limit switch. The dial indicator gauge/limit switch actuates to turn off the rotary tool when the nose, at room temperature, has moved to the preselected position past the seat as indicated in  FIG. 9 . Further warming will simply move the nose slightly further down, as seen in  FIG. 9 , but the dial indicator gauge and/or limit switch  315  has properly positioned the nose with respect to the seat, such that the valve will unseat when the first set temperature, typically the freezing point or freezing range of the working material, is reached, opening the valve as seen in  FIG. 4  or  7 A. 
         [0064]    The combination of a pressure switch with Applicant&#39;s mechanical or electrical purge valve in close proximity thereto, may be used in any suitable environment where the pressure switch may be exposed to ambient freezing conditions. Exemplary of these environments are the following: water wells, reverse osmosis systems, ice machines, water level controls (depth gauges and large tanks), aerobic septic systems, lawn sprinkler systems, fire sprinkler systems, geothermal AC systems, cooling tower AC systems, and gray water distribution systems. While the 0 to about 12 inches is measured typically from the diaphragm surface along the water path to the inlet of valve  10  or solenoid  126 , other distances may be suitable, including preferably between about 2 to about 8 inches. 
         [0065]    Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. On the contrary, various modifications of the disclosed embodiments will become apparent to those skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover such modifications, alternatives, and equivalents that fall within the true spirit and scope of the invention.