Abstract:
A thermostatic regulator ( 30 ) for a single handle mixer valve ( 12 ) has a sensor ( 32 ) mounted in a mixed water chamber ( 34 ) for sensing the temperature of the outlet water. The sensor is connected to a valve ( 20 ) that is mounted in the cold water supply line ( 18 ) to restrict the availability of cold water when the water in the hot water line ( 16 ) is down below a set temperature.

Description:
TECHNICAL FIELD 
     This invention relates to a mixing valve for cold and hot water of the type including a thermostatic device and a manual control device acting upon the inlet ports that pass the cold and hot water to a mixing region. 
     BACKGROUND OF THE INVENTION 
     According to Italian Patent No. 1,107,182 by the same inventor, a thermostatic faucet includes a mixer with manual control that sets a mixing ratio between cold water and hot water and a thermostatic device that, depending on the actual temperature of the mixed water, controls a choke valve inserted on the hot water supply to the manual control mixer so as to modify the mixing ratio set in order to maintain within a certain range the temperature of the mixed water that is actually delivered. 
     According to Italian Patent No. 1,279.194, by the same inventor, a thermostatic faucet includes a mixer with manual control that sets a mixing ratio between cold water and hot water and a thermostatic device that, depending on the actual temperature of the mixed water, controls a choke valve inserted on the cold water supply to the manual-control mixer so as to modify the mixing ratio set in order to maintain, within a certain range, the temperature of the mixed water that is actually delivered. 
     Both of these devices incorporate a certain material separation between the manually controlled mixer valve and the thermostatic device that complicates its design and installation. 
     According to Italian Patent No. 1,2273,178, a thermostatic mixing device to which one can also operate as a faucet includes inlet ports for cold water and hot water, arranged at the sides of a central outlet pipe. A mixing chamber receives water from regulated hot and cold inlet passages and a thermostatically controlled distribution valve operates so as to control the opening and closing in opposite directions of the respective regulated inlet hot and cold passages so as to maintain, within a certain and adjustable range, the temperature of the discharged mixed water. This device can be provided with a volume flow control valve for manually and simultaneously changing the useful opening of both hot and cold inlet pipes. The volume flow valve controls only the flow volume but does not have any effect on the mixing action or relative proportional of flow of hot and cold water. This device presents a general and particularly advantageous structure, although it does entail the inconvenience that temperature regulation is rather poorly sensitive and gives rise to a temporary over regulation phenomena (of referred to as an “overshoot”). Temporary overshoot occurs when upon movement of the temperature adjustment mechanism to a position corresponding to a given temperature, one initially gets an effective temperature change of discharged water that is considerably more than the desired change. The desired temperature change is reached only after a period of time after the thermostatic device had a chance to compensate. The adjustment of the temperature, controlled by the thermostatic element, is achieved by manual control of the position of the thermostatic element and the distribution valve operably connected to it, which directly affects the opening of the respective hot and cold inlets. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of this invention, a thermostatic mixing valve can be used alternatively as a thermostatic faucet or as a thermostatic device for feeding one or several apparatus, each of which is provided with its own faucet, or with one or several faucets installed downstream from the thermostatic device. The thermostatic mixing valve combines the advantages of the prior art devices without entailing the installation or thermostatic overshoot inconveniences. In particular, the invention is a compact structure that is easy to make and install and ensures a high degree of adjustment sensitivity. It further can provide a guarantee against the delivery of excessively hot water also in the presence of abnormalities in water supply and, when it is used as a thermostatic faucet, it incorporates a manually operated sequential type control valve mounted in series with the thermostatic valve. 
     Preferably, the thermostatic mixing valve comprises two inlet ports for cold water and hot water, a mixing chamber, passages between the inlet ports and the mixing chamber, a discharge port from the mixing chamber for mixed water, a thermostatic element arranged at least partly in the mixing chamber, and an annular distribution slide valve controlled by the thermostatic element. Both inlet ports and discharge port are in a central body radially inside the annular distribution slide valve. The annular distribution slide valve is arranged so as to restrict the passage between only one of the inlet ports and the mixing chamber. A flow and mixing adjustment valve with manual control of the sequential type is mounted to control the two inlet ports. 
     The adjustment of the temperature of discharged water is set manually by the action of the manually operable sequential type control valve for the flow and the mixing action without the manual action directly changing the position of the thermostatic element and the distribution slide valve so that one can systematically eliminate the phenomenon of temporary overshoot. Furthermore, the action of adjusting the distribution slide valve, controlled by the thermostatic element, always works in a counteracting direction from the direction of manual action thereby limiting its effect. The consequence of two counteracting activities is that one must make a longer movement of the manual control to achieve a desired change. The gradation of adjustment is elongated and the profile of change is flatter. The quickness and precision of thermostatic adjustment are then enhanced by the fact that the distribution slide valve works so as to effectively restrict or increase flow cross section of only one of the inlet ports so that the mixing takes place due to the addition or restriction of only one flow to the volume of the other flow rather than through inverse variation of the volumes of the two flows. 
     In cases where the valve is used as a faucet, the manual operable sequential valve also intercepts or shuts off the delivered volume, functions as a non-return valve, and adjusts flow rate within certain limits. But the manual sequential valve inserted in the water supply lines can also be used as a thermostatic adjustment device for a water supply flow going to one or several apparatuses, each of which is provided with its own shut off and volume regulation valve or with one or several faucets inserted in the waterlines downstream from the thermostatic valves. In these cases, the manual control valve for the thermostatic valve is adjusted only to determine the desired temperature and not to intercept a shut-off water flow or regulate it. 
     In cases where one must ensure an upper limit of the temperature of the discharge water, the distribution slide valve is so positioned as to regulate, by the action of the thermostatic element, the cross-sectional area of the passage through which hot water passes from the pertinent inlet port to the mixing chamber. 
     On the other hand, in cases where it is not necessary to limit the temperature of the discharge water (for example, because hot water supply is provided at a limited or non-hazardous temperature), the distribution slide valve can also be arranged so as to regulate, by the action of the thermostatic element, the cross-sectional area of the passage through which cold water passes from the pertinent inlet port to the mixing chamber. 
     Preferably, when the valve is intended to be used a thermostatic faucet the manually operable sequential valve includes a pair of valve plates, preferably made of hard material with openings therethrough. A first fixed plate and a second moveable plate are in sliding contact with each other. The openings in the plates are positioned to ensure in succession a shut-off or intercept position, a range of sequential opening positions of the pertinent passage for cold water while retaining closure of passage for hot water, a range of positions for the sequential opening of a passage for hot water while retaining full opening of the passage for cold water and, finally a range of sequential closing of the passage for cold water while retaining full opening of the passage for the hot water. The two plates each present an outlet opening that is permanently open to the mixed flow. 
     As an alternative, the two ranges of positions can be replaced by a single range of positions in which there takes place a sequential opening of the passages for the hot water and simultaneously a sequential closing of the passages for the cold water. 
     The sequential action can be achieved, for example, with a plate valve structure that has a first plate that is symmetrical with respect to a diameter of the openings therethrough and with a second plate that is asymmetrically constructed with respect to a diameter of its openings, cooperating with the first plate openings. It is immaterial whether the first plate is fixed and the second plate is moveable or vice versa. In a particularly convenient arrangement, the sequential valve includes a fixed base plate intended to be mounted upon a supply and delivery housing, and a rotatable plate mounted rotatably on said base plate and which is manually operated. Preferably, the fixed base plate is mounted in the supply and delivery housing and the moveable part is mounted in a rotatable body of the valve and operable by a handle, lever, or knob. 
     The valve can be provided with an adjuster to determine and adjust the maximum temperature at which the delivered water can be adjusted. The adjuster adjusts the resting position of the thermostatic element and of the distribution slide valve connected to it. This device can include a cap that can be rotated by manual action, mounted through a working threaded connection to the rotatable body of the valve. As the cap is rotated relative to the rotatable body, the cap also axially shifts the support point to the thermostatic element. 
     In accordance with a broader aspect of the invention a thermostatic mixing valve has a base having two supply ports and a rotatable body mounted onto the base and operably connected to a first valving surface with a first and second inlet passages therethrough that are operably positioned adjacent the two supply ports for controlling volume flow into the housing. A second valving member is annular in shape and movable toward and away from an annular seat in proximity for restricting and controlling fluid only from said first inlet passage. The first inlet passage passes up through the annular seating surface within radial extent of said annular valving surface and having a downstream end in fluid communication with the annular seat and the annular valving member to provide a first annular flow path between the annular seat and the annular valving member from radially within the annular valving member to radially outside of the annular valving surface to a mixing chamber. The first inlet passage is sealed within the interior of said annular valving surface with respect to the second inlet passage from the supply ports to the mixing chamber. A thermostatic element is axially movably disposed within the mixing chamber and operably connected to the annular valving surface to move the annular valving surface axially toward and away from the annular seat for restricting controlling the flow form only the first inlet passage into the mixing chamber in response to the temperature of fluid in the mixing chamber. The mixing chamber is in fluid communication with an outlet exiting therefrom. 
     Preferably, the annular seat opposes an axial end of said annular valving member. The second inlet passage passes up through the first seating surface and through the interior of the annular valving surface within the radial extent of the annular valving surface and having a downstream end in unrestricted fluid communication with the mixing chamber. 
     Alternatively the second inlet passage ends below the annular valving member to allow free unrestricted flow about the annular valving member to the mixing chamber and the annular seat is positioned above the annular valving member and the first inlet passage passes up through the interior of the annular valving member. 
     Preferably, a return biasing spring is mounted within the radially confines of the annular valving member to axially move said annular valving member upon contraction of the thermostatic element. 
     In one embodiment the return biasing spring is mounted on the top of a central body within said rotatable body. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference is now made to the accompanying drawings, in which: 
     FIG. 1 is a segmented side elevational view illustrating a first embodiment of the thermostatic valve according to the invention; 
     FIG. 2 illustrates an embodiment of the fixed plate for the sequential manual operating valve for controlling the flow and the mixing action shown in FIG. 1; 
     FIG. 3 illustrates an embodiment of the movable plate for the sequential manual operating valve; 
     FIGS. 4 to  7  illustrate the movable plate of FIG. 3 rotated in various adjusting positions on the fixed plate of FIG. 2; and 
     FIG. 8 illustrates a segmented view similar to the one in FIG. 1 displaying a second embodiment of the thermostatic valve according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, a thermostatic mixing valve  10  includes a rotatable handle body  12  that is rotatably mounted in piping fixture or other suitable piping fixture  14 . The piping fixture  14  includes a cold water supply  16  and hot water supply  18 . The rotatable handle body  12  is rotatably mounted to a faucet base  17  that is affixed within the fixture  14  by projection  19  inserted in the seat  21  of the fixture  14 . The body  12  is retained to base  17  by collar  23  threaded into the seat  21  of fixture  14 . Seals  13  are seated on base  17  about a cold water inlet port  20  and a hot water inlet port  22 . 
     Rotatable body  12  comprises an inner shell  25  that can be quipped with a cosmetic operable handle or knob  26 , preferably made of thermally insulating material, so shaped as to facilitate the manual operation for the rotation of rotatable body  12 . Inside shell  25  there is arranged a central body member  28 , which is fixed to shell  25  for rotation therewith. The central body  28  is intended to cooperate with a distribution annular slide valve  44 . 
     The internal body member  28  has a cold water inlet passage  30  aligned with the cold water inlet port  20  and a hot water inlet passage  31  aligned with the cold water inlet port  22 . A central mixed water outlet  33  is in communication with discharge port  34  and outlet  36  in fixture  14 . The passage  30  has an annular shaped downstream end  40  adjacent an annular valve seat  40 . The downstream end is also adjacent the axial upper valve lip  42  of an annular slide valve  44 . Downstream end  46  of hot water inlet  31  is annular in shape and is unrestricted by the wide spacing between the lower end  48  of valve  44  and opposing annular surface  50 . There is also a sufficient annular gap between the rotatable body  25  and valve  44  and its mounting collar  57  to provide an unrestricted passage to flow opening  57  and into mixing chamber  59 . 
     Valve seat  40  is secured to the internal body member  28 . The passage  30  passes axially through the annular valve  44  within its radial confines. The internal body member  28  has an intermediate seal seat  52  that seats a gasket  54  that seals off the passage  30  from  31  within the axial extend of the annular slide valve  4 T. 
     The annular slide valve  44  is affixed to the collar  56  via a threaded engagement  58 . The collar  56  and slide valve  44  outlines a mixing chamber  59  between flow ports  57  and mixed water outlet  33 . A spring  60  is mounted within the annular valve  44  and collar  56  and is seated on the top seat  40  on the top of the central body  28 . The spring  60  biases the valve  44  to engage the seat  40  and close off passage  38 . The collar  56  extends above the internal body section  28  and is operatively affixed through a safety spring release collar  72  and spring  74  to body section  62  of thermostatic element  64 . The thermostatic element  64  has an expanding piston leg  66  that engages an abutment member  68  that is mounted in adjustment handle  70 . The adjustment handle  70  has a threaded connection  76  to shell  25  and an appropriate seal  75  for mechanically raising and lowering the thermostatic assembly  64  within the shell  25 . The body section  62  may extend into the central outlet passage  33  of the internal body  28 . 
     The mixing valve includes a sequential flow rate control valve  80  that includes two ceramic disc plates  82  and  84 . Fixed ceramic disc plate  82  is mounted in base  17 . Rotatable (or movable) ceramic disc plate  84  is mounted to a bottom of the center body  28 . The sequential flow rate control valve  80  is mounted upstream from the annular slide valve  44 . The fixed ceramic disc plate  82  has respective cold and hot supply ports  86  and  88  and a centrally located mixed water outlet port  90 . The movable ceramic disc plate  84  has a cold water inlet  92  and hot water inlet  94  and a centrally located outlet aperture  96 . Aperture  96  is in constant alignment with outlet port  90  of fixed ceramic disc plate  82  and central outlet passage  33  of body  28  and discharge port  34 . The rotation of the handle  26 , and shell  25  with center body  28  rotates the ceramic disc plate  84  with respect to disc plate  82  to selectively align or misalign the inlets  92  and  94  with inlets  86  and  88  to control the flow rate of the hot and cold water. 
     As clearly illustrated in FIG. 2, openings  86  and  88  of fixed plate  82  are symmetrically positioned with respect to a central diameter  97  of the fixed plate. The openings  86  and  88  have arced, slotted shapes. Other shapes may also be employed. Inlet openings  92  and  94  of the movable plate  84 , as illustrated in FIG. 3, are asymmetrical with respect to a central diameter  98  of the movable plate  84 . Diameter  98  of moveable plate  84 , when the plates  82  and  84  are in the intercept or shut-off position, as shown in FIG. 4, corresponds to the diameter  96  of the fixed plate. It is also possible to select other arrangements of the openings  86 ,  88 ,  92  and  94  that are equally suitable for bringing about correct operation (specified below). Furthermore, plates  82  and  84  can switch places such that plate  82 , with its openings can become moveable and plate  84  with its opening can become fixed. 
     Plates  82  and  84  together provide for the sequential adjustment of the flow and the mixing action, cooperating as shown in FIGS. 4 to  7  as a function of the rotation imparted to rotatable body  12  of the thermostatic valve with respect to fixed base  17 . 
     In FIGS. 4 to  7 , the two plates  82  and  84  are shown with movable plate  84  superimposed over fixed plate  82 . Openings  92  and  94  of mobile plate  84  thus are in view, while openings  86  and  88  of fixed plate  82  (marked by graph-paper-like lines) are entirely or partly covered by mobile plate  84 . 
     In the position illustrated in FIG. 4, openings  92  and  94  of movable plate  84  are completely misaligned from openings  86  and  88  of fixed plate  82 . This is, therefore, an intercept or shut-off position. On the other hand, discharge outlets  90  and  96  are permanently aligned in this position, as in all other positions of plates  82  and  84 , so that outlet passage  33  of central body  28  of the valve will permanently communicate with outlet discharge  36  of fixture  14 . 
     In the position illustrated in FIG. 5, movable plate  84  has been rotated by a certain angle in a counterclockwise direction (along arrow  100 ) with respect to the position in FIG.  4 . In the entire range of positions, between the positions shown in FIGS. 4 and 5, the passage opening  92  of movable plate  84  becomes partly or totally aligned to opening  86  of fixed plate  83 , while opening  94  of movable plate  84  retains total misalignment with opening  88  of fixed plate  82 . Therefore, in the rotation from the position in FIG. 4 to the position in FIG. 5, there is a progressively growing flow rate that is offered to the cold water, while the hot water remains intercepted or shut off. 
     In the position illustrated in FIG. 6, movable plate  24  is further rotated by a certain angle in the clockwise direction (along arrow  100 ) with respect to the position in FIG.  5 . In the entire range of positions between the positions shown in FIGS. 5 and 6, the passage opening  94  of movable plate  84  becomes partly or totally aligned to opening  88  of fixed plate  82  while opening  92  of movable plate  84  continues to retain substantially complete alignment with opening  86  of fixed plate  82 . Therefore, in the passage rotation from the position in FIG. 5 to the position in FIG. 6, there is progressively growing flow rate that is offered to the hot water, while the passage offered to the cold water remains fully open. There is thus a progressive addition of hot water to the cold water. The axial profile in FIG. 1 shows the passages for both the cold water and the hot water as being open which corresponds to the profile marked along line I—I shown in FIG.  6 . 
     Finally, in the position shown in FIG. 7, the movable plate has again been rotated by a certain angle in the counterclockwise direction (along arrow  100 ) with respect to the position in FIG.  6 . In the entire range of positions between the positions shown in FIGS. 6 and 7 passage opening  94  of movable plate  84  continues to retain substantially complete alignment with opening of fixed plate  82 , while opening  92  of movable plate  84  gradually becomes totally misaligned from opening  86  of fixed plate  82 . Therefore, in the rotation from the position in FIG. 6 to the position in FIG. 7, a progressively decreasing flow rate is offered to the cold water, whereas the passage opened to the hot water remains fully open. There is thus a progressive passage from mixing action to the delivery of only hot water. 
     As an alternative, the two ranges of intermediate positions between the positions of FIGS. 5 and 7 can be replaced by a single range in which a gradually growing passage is offered to the hot water, while the passage offered to the cold water gradually and simultaneously decreases. 
     The two plates  82  and  84 , with their openings  90  and  96 , therefore provide a sequential control valve  80  for flow and the mixing action, which can be controlled manually by rotating body  12  of the valve using handle  26  that operates a shell  25 . With the help of this manual sequential control valve  80 , one can set a cold water volume to mixing ratio, which are intended to be subsequently corrected by the action of the thermostatic device  64 . 
     The description refers to the case of a thermostatic mixing valve that can be used as faucet with a shut off position. In cases where, on the other hand, the valve is intended to work as a supplier for one or several apparatuses and where the function of intercepting and adjusting the volume is downstream from this valve  10  the intercept or shut off position and the range of positions corresponding to a progressively growing passage offered to the cold water, while the hot water remains shut off, can be eliminated. 
     The thermostatic device works in the following manner. The mixing chamber  59  receives hot water through flow ports  27 , while cold water flows from ring-shaped chamber  38  in respective proportions that are set manually by the sequential control valve  80  previously described. The hot and cold water are mixed in mixing chamber  59  and discharged through outlet passage  33 , through discharge port  34  and outlet  36  in fixture  14 . This mixed water surrounds thermostatic element  64 , which assumes the same temperature and expands or contracts correspondingly. The expansion or contraction of thermostatic element  64  moves the distribution slide valve  44  down or up respectively. When the water warms the thermostatic element  64 , it dilates, moves slide valve  44  down and the annular seat  42  moves away from the surface of seat  40  thus widening the passage between annular chamber  38  and mixing chamber  59 . This reduces the resistance against the flow of cold water and the volume of this flow increases, reducing the temperature of the mixed water. If at that point the manual sequential control valve  80  is again adjusted to increase the temperature, then there will also be an increase in the dilation of thermostatic element  64 , and the passage between annular chamber  38  and mixing chamber  29  becomes even wider with even less resistance thus further increasing the flow rate of cold water. One can thus see that the thermostatic device  64  tends to act against manual adjustment so that the latter must be performed with greater amplitude to attain the desired temperature in the mixed water. The fine adjustment capability for small temperature changes is thus enhanced. 
     Furthermore, any voluntary adjustment of the manual sequential valve to adjust temperature does not directly cause an axial shift in the distribution slide valve, an axial shift that must successively be compensated by the thermostatic device to attain a condition of equilibrium. Thus, there will be no phenomena of temporary overshoot. 
     The operation of handle  70  in this thermostatic valve axially moves the entire thermostatic element  64  and collar  56  with slide valve  44  up and down. However, contrary to what is customary, the movement of handle  70  does not help adjust the temperature but rather to adjust the maximum limit of the temperature that can be reached (under normal conditions of supplies) in the drawn mixed water. 
     It is obvious that, on the other hand, the temperature of the delivered water can rise higher than this limit eventually up to the point where it reaches the temperature of the hot water supplied only supply pipe  18  if there are abnormalities or, at the utmost, if there is a total lack of supply from cold water supply pipe  16 . Nevertheless, the embodiment described is advantageous both in cases where the temperature of the hot water supplied by pipe  18  is not dangerous and by the fact that the passage of the hot water into the valve is entirely free (except for voluntary control) and is therefore particularly favorable in cases where the hot water is supplied at low pressure. 
     If one wishes to introduce a device that prevents the delivery of hot water with high temperature, one can employ the embodiment according to FIG.  8 . The latter to a great extent corresponds to the previously described embodiment and the corresponding parts, which are labeled with the same references, will therefore not be described again. The axial cross-section of this figure is also the same as that shown in FIG.  1 . 
     The basic difference between the embodiment according to FIG. 8, as against the embodiment according to FIG. 1, is in the fact that thermostatic adjustment takes place on the passage  31  of hot water rather than on the passage  30  of cold water. Inlet passage  30  for cold water has its annular chamber  38  freely empty into mixing chamber  50 . On the other hand, inlet passage  31  for hot water empties into an annular chamber  46 , and the active annular part  48  of distribution slide valve  44  surrounds this annular chamber  46  and cooperates with a lower surface  50  presented by central body  28  to controllably restrict flow into mixing chamber  59 . 
     This valve works in a manner identical to the one described earlier, but thermostatic adjustment following a dilation of thermostatic element  23  involves choking or restricting the passage of the hot water rather than widening the passage of the cold water. It follows from this that in case of any anomaly in cold water supply, the volume of mixed water is reduced enough to stay within the temperature limit set by the valve, and in case of total absence of cold water supply, the valve would cease to deliver water altogether. 
     In all of its embodiments, the thermostatic valve according to the invention can be used as thermostatic faucet that is operated in a progressive manner, making shell  25  of the valve rotate by virtue of the operation of handle  26 . 
     However, it is also possible to use the valve to supply one or several apparatus, such as, for example, showerheads, each provided with its own volume control and intercept faucet or with one or several faucets inserted in the pipe downstream from the thermostatic valve. In this case, the thermostatic valve is adjusted manually only to set the desired temperature, while the volume and shut off valves are adjusted downstream on the faucets on the various apparatuses. 
     As with all thermostatic valves that do not act as a faucet, which as such do not ensure a separation between the hot water and cold water supply pipes, optional non-return valves in the lines may be inserted for ensuring this separation. 
     It must be understood that the invention is not confined to the embodiments described and illustrated by way of example. Some modifications have been described and others are within the reach of the expert in the field; for example, the shape and arrangement of the passage openings of plates  82  and  84  can be modified, provided they give rise to the succession of actions described earlier. The arrangement of other parts of the valve can also be modified. Cap  70  for adjusting the attainable temperature limit can be omitted when this adjustment is predetermined by way of design, or this adjustment can be performed with setting members that are accessible to the action of a technician but which the casual user cannot operate. 
     These and other modifications and any substitution with technical equivalents can be introduced in what was described and illustrated above without deviating from the scope of the invention and the coverage of this patent.