Patent Abstract:
A thermostatic mixing valve includes a mixing slide arranged between two seats for mixing fluids at different temperatures and capable of flowing between the mixing slide and the two seats, respectively, so as to supply a mixed fluid; and an axial thermal actuator arranged between the mixing slide and an absorption member sensitive to the temperature of the mixed fluid for creating a controlled movement of the position of the mixing slide between the two seats in order to supply the mixed fluid at a controlled temperature, where the absorption member includes one of the seats and is capable of moving in a direction that increases the distance between the seats when the mixing slide is bearing on the other seat so as to absorb an excess of axial movement of a rod of the absorption member due to excessive variation of the mixed fluid temperature.

Full Description:
This application is the U.S. national phase, pursuant to 35 U.S.C. §371, of PCT international application Ser. No. PCT/FR2010/050315, filed Feb. 24, 2010, designating the United States and published in French on Sep. 2, 2010 as publication WO 2010/097545 A1, which claims priority to French Application Ser. No. 0951207, filed Feb. 26, 2009. The entire contents of the aforementioned patent applications are incorporated herein by this reference. 
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates to the field of thermostatic valves for mixing fluids at different temperatures in order to obtain a fluid at a controlled temperature. 
     (2) Description of the Related Art 
     Such valves can be used in particular in the field of domestic sanitary installations in order to supply domestic water at a controlled temperature and in the field of the regulation of heating water in all sorts of applications. 
     Known thermostatic mixing valves comprise a mixing slide that slides between two fixed seats, the hot water and the cold water being supplied through spaces between the mixing slide and each of these two fixed seats. The slide is actuated by a thermal actuator containing a product, the volume of which varies with temperature and the variation in volume of which controls the position of the slide between the two fixed seats. 
     SUMMARY OF THE INVENTION 
     The aim of the present invention is to improve such thermostatic valves. 
     There is provided a thermostatic mixing valve which may comprise a mixing means that is able to move between two seats in order to mix fluids at different temperatures that are able to pass between the mixing means and each of these two seats in order to supply a mixed fluid; and an actuating means fitted between the mixing means and an absorption member, said actuating means being sensitive to the temperature of the mixed fluid in order to produce a travel regulating the position of the mixing means between the two seats so as to supply a mixed fluid at a regulated temperature. 
     Said absorption member may have one of said seats and may be able to be moved in the direction of the increasing distance between the two seats when the mixing means is bearing against the other seat, so as to absorb an excess travel of the actuating means under the effect of an excess in variation in the temperature of the mixed fluid. 
     There is provided a thermostatic mixing valve which may comprise a casing having an axial internal space in which there are arranged an annular seat and a shoulder, which are spaced apart axially from one another and are oriented in the same axial direction, a first lateral communicating passage between a first inlet for the inlet of a hot fluid and the internal space, a second lateral communicating passage between a second inlet for the inlet of a cold fluid and the internal space and a third communicating passage between the internal space and an outlet located downstream of the seat of the casing for the outlet of a mixed fluid that results from the mixing; an absorption member which is mounted such that it can slide axially in said internal space and is urged toward said shoulder by a first spring; a mixing slide which is mounted such that it can slide axially in said internal space between the seat of the casing and the absorption member and is urged toward said absorption member by a second spring, this slide having an axial passage, said first lateral communicating passage being able to be closed off by the sliding mixing slide when the latter engages with the seat of the casing and said second lateral communicating passage being able to be closed off by the sliding mixing slide when the latter engages with a seat of said absorption member; and an axial thermal actuator comprising a body containing a product, the volume of which varies with temperature, and an axial rod, the position of which with respect to the body varies depending on the volume of the product, the body of the actuator being secured to the slide and positioned at least partially in the third communicating passage, and the rod of the actuator being able to come axially into contact with said absorption member. 
     The absorption member may comprise a plate that is able to bear against said shoulder and has said seat and a hub that can be regulated axially with respect to the plate, the rod of the thermal actuator being able to come into contact with this axial hub. 
     The sliding mixing slide may comprise an external part mounted such that it can slide in an annular part of the casing separating the first and second communicating passages and a central part connected to this external part and on which the body of the thermal actuator is mounted. 
     A spacer may be mounted on the body of the thermal actuator, the second spring being inserted between this spacer and a part of the casing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A thermostatic mixing valve will now be described in a nonlimiting manner with reference to the drawing, in which: 
         FIG. 1  shows a longitudinal section through a thermostatic mixing valve in a position for mixing hot water and cold water; 
         FIG. 2  shows a longitudinal section through the thermostatic mixing valve from  FIG. 1  in a position of closure of the cold water inlet; 
         FIG. 3  shows a longitudinal section through the thermostatic mixing valve from  FIG. 1  in a position of closure of the hot water inlet; 
       and  FIG. 4  shows a longitudinal section through the thermostatic mixing valve from  FIG. 1  in a position of closure of the hot water inlet and of excess travel. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The thermostatic mixing valve  1  shown in the figures comprises a casing  2  which comprises a longitudinal tubular part  3  established along an axis  4 . 
     This longitudinal tubular part  3  has an end piece  5  forming an outlet  6 , to which there may be connected an outlet duct, a central part  7  and an end piece  8  opposite the end piece  5 . 
     Formed in the central part  7  is an internal space  9 , in which there are formed, in succession starting from the outlet  6 , a cylindrical communicating passage  10 , an annular shoulder constituting an annular seat (hereinafter referred to as “annular seat” or “seat”  11 ), an annular groove  12 , one side of which prolongs the annular seat  11 , a cylindrical portion  13 , a cylindrical part  14 , an annular shoulder  15  and a cylindrical portion  16 . Thus, the annular seat  11  and the annular shoulder  15  are oriented in the same axial direction. 
     The diameter of the cylindrical portion  13  is smaller than the diameter of the cylindrical passage  10 . The diameter at the bottom of the annular groove  12  and that of the cylindrical part  14  are larger than the diameter of the cylindrical portion  13 . The diameter of the cylindrical portion  16  is larger than the diameter of the cylindrical part  14 . 
     The casing  2  furthermore comprises opposite lateral branches  17  and  18 , forming a first inlet  19  and a second inlet  20 . The first inlet  19  communicates with the internal space  9  of the tubular part  3  through a passage  21  which opens into the groove  12 . The second inlet  20  communicates with the internal space  9  of the casing  2  through a passage  22  which opens into the cylindrical part  14 . 
     The mixing valve  1  also comprises an axially sliding absorption member  23 , which comprises a plate  24  positioned radially in the cylindrical part  16  of the tubular part  3  and a cylindrical axial hub  25 , one end of which is screwed into the central part of the radial plate  24  and the other end of which is inserted such that it can slide in a cylindrical axial part  26  of an end cap  27  screwed into the end piece  8 . 
     An annular seal  28  is inserted between the axial hub  25  and the axial part  26  of the end cap  27 . An annular seal  29  is inserted between the end cap  27  and the end piece  8 . 
     A helical spring  30  is inserted between the plate  24  of the absorption member  23  and the end cap  27 , this spring  30  urging the absorption member  23  in the direction which moves the plate  24  axially closer to and brings it into abutment against the shoulder  15 . 
     The mixing valve  1  also comprises a mixing means consisting of a mixing slide  31  which comprises an external cylindrical tubular part  32  which is mounted such that it can slide in the cylindrical portion  13  of the internal space  9  of the casing  2 , with an annular seal  33  being inserted in between. This external tubular part  32  is able to move axially between the seat  11  of the casing  2  and the plate  24  of the absorption member  23  and has an annular end  32   a  that is able to come into sealing contact with the seat  11  and an annular end  32   b  that is able to come into sealing contact with an annular region of the plate  24  that forms a seat  11   a , facing the spring  30 . 
     The mixing slide  31  further comprises an internal cylindrical tubular part  34  connected to the external tubular part  32  via radial arms  35 , such that the mixing slide  31  has an axial passage  36  between these tubular parts  32  and  34 . 
     The mixing valve  1  also comprises an actuating means consisting of an axial thermal actuator  37 , which comprises an axial body  38  containing a product, the volume of which varies with temperature, and an axial rod  39  which passes through a front part  40  of the body  38  and the axial position of which with respect to the body  38  varies depending on the volume of the product. This product may be based on wax. 
     The front part  40  of the body  38  is mounted in the internal tubular part  34  of the mixing slide  31  and a protruding annular part  41  of this body  38  is in abutment against one end of this internal tubular part  34 , such that the body  38  extends largely downstream of the seat  11  in the internal space  9  of the casing  2 , on the outlet  6  side, and such that the rod  39  is able to move axially against the hub  25  of the absorption member  23 , on the same side as the end  32   b  of the mixing slide  31 . 
     An annular spacer  42  is mounted around and at a distance from the body  38  of the thermal actuator  37  and has internal wings  43  in contact with the body  38  and in axial abutment against the protruding annular part  41  of this body  38 , such that there is an axial passage  44  between the body  38  of the actuator  37  and the annular spacer  42 . The peripheral surface of the annular spacer  42  can be adjusted such that it can slide and be guided in the cylindrical part  10  of the casing  2 . 
     A helical spring  45  is inserted between the annular spacer  42  and an internal shoulder  46  of the end piece  5 , such that this spring  45  acts axially on the movable assembly formed by the mixing slide  31 , the body  38  of the thermal actuator  37  and the spacer  42  in the direction which spaces the end  32   a  of the external tubular part  32  of the mixing slide  31  apart from the seat  11 . 
     The thermostatic mixing valve  1  can function in the following manner. 
     The inlet  19  in the casing  2  is connected to a source of hot water EC and the inlet  20  in the casing  2  is connected to a source of cold water EF. 
     Mixed or warm water EM, which is produced by controlled mixing of the inlet hot water and the inlet cold water, exits through the outlet  6 . 
     This outlet mixed water EM can be at a temperature between a low temperature threshold Sb and a high temperature threshold Sh, the values of which depend on the thermal characteristics of the thermal actuator  37 , producing the axial movement of the rod of the actuator  39  with respect to its body  38 , on the axial adjustment of the hub  25  of the absorption member  23  with respect to the axial rod  39  of the thermal actuator  37 , and on the travel of the external tubular part  32  of the mixing slide  31  between the seat  11  and the seat  11   a  on the plate  24  of the absorption member  23 . 
     As is shown in  FIG. 1 , the hot water EC is mixed with the cold water EF in the following manner. 
     When the temperature of the outlet mixed water EM is between the low threshold Sb and the high threshold Sh, the annular ends  32   a  and  32   b  of the external part  32  of the mixing slide  31  are each spaced apart from the annular seat  11  on the casing  2  and from the seat  11   a  on the plate  24  of the absorption member  23 , the plate  24  being in abutment against the shoulder  14  under the effect of the spring  30 , whereas the rod  39  of the thermal actuator is in abutment against the hub  25  of the absorption member  23  under the effect of the spring  45 . 
     Hot water EC passes through the communicating passage  21  and toward the inside between the annular end  32   a  and the annular seat  11 . At the same time, cold water EF passes through the communicating passage  22 , towards the inside between the annular end  32   b  and the plate  24  and through the axial passage  36  in the mixing slide  31 . The flow of hot water EC and the flow of cold water EF meet approximately at the annular seat  11  and are mixed so as to obtain a flow of mixed water EM, which passes axially around the body  38  of the thermal actuator  37  in the direction of the outlet  6 . The volume of the product enclosed in the thermal actuator  37 , which determines the axial position of the rod  39  with respect to the body  38  of the thermal actuator  37 , which determines the position of the mixing slide  31 , enables the above functional situation. 
     When the temperature of the mixed water EM drops toward the low threshold Sb, the volume of the product enclosed in the thermal actuator  37  decreases, the rod  39  moves into the body  38  of the thermal actuator  37  and the mixing slide  31  moves away from the annular seat  11  and toward the plate  24 . The inlet for hot water EC increases in size and the inlet for cold water EF decreases in size. 
     When the temperature of the mixed water EM climbs toward the high threshold Sh, the volume of the product enclosed in the thermal actuator  37  increases, the rod  39  leaves the body  38  of the thermal actuator  37  and the mixing slide  31  moves toward the annular seat  11  and away from the plate  24 . The inlet for hot water EC decreases in size and the inlet for cold water EF increases in size. A situation in which the temperature of the outlet mixed water EM is regulated between the low threshold Sb and the high threshold Sh is thus produced. 
     As is shown in  FIG. 2 , when the temperature reaches the low threshold Sb, the reduction in volume of the product enclosed in the thermal actuator  37  causes the end  32   b  of the external part  32  of the mixing slide  31  to reach the plate  24  of the absorption member  23  and the external part  32  of the mixing slide  31  to close the inlet for cold water EF. 
     When the temperature drops below the low threshold Sb, this situation is maintained and the rod  39  of the thermal actuator  37  moves away from the hub  25  on account of the reduction in volume of the product contained in the thermal actuator  37  which is caused by the excessive reduction in the temperature of the mixed water. The loading of the springs  30  and  45  with respect to one another is adapted to produce this situation. In fact, the axial force of the spring  30  is greater than the axial force of the spring  45 . As a result, the inlet of cold water EF is cut and only the inlet of hot water EC takes place, thereby causing the temperature of the product contained in the thermal actuator  37  to rise again and the product to increase in volume in order to bring about opposite movements and to reestablish the regulating situation described with reference to  FIG. 1 . 
     As is shown in  FIG. 3 , when the temperature reaches the high threshold Sh, the increase in volume of the product enclosed in the thermal actuator  37  causes the end  32   a  of the external part  32  of the mixing slide  31  to reach the annular seat  11  and the external part  32  of the mixing slide  31  to close the inlet passage  21  for hot water EC. 
     When the temperature exceeds the high threshold Sh, this situation is maintained. Since the volume of the product enclosed in the thermal actuator  37  continues the increase under the effect of an excessive increase in the temperature of the mixed water EM, the rod  39  of the thermal actuator  37  bearing against the hub  25  causes the absorption member  23  to move counter to the spring  30  by moving the plate  24  away from the shoulder  15 , thereby increasing the distance between the seat  11   a  on the plate  24  and the seat  11  on the casing  2 . 
     As is shown in  FIG. 4 , the result of the above situation is that the inlet of hot water EC is cut and only the inlet of cold water EF takes place, thereby causing the temperature of the product contained in the thermal actuator  37  to fall and the product to decrease in volume in order to bring about opposite movements and to reestablish the regulating situation described with reference to  FIG. 1 . 
     The temperature thresholds Sh and Sb for the functioning of the valve  1  can be adjusted by adjusting the axial position of the cylindrical axial hub  25  with respect to the radial plate  24 , by screwing or unscrewing the hub by virtue of a screwdriver which can be brought into engagement with a slot  47  formed in the end of the hub  25 , this slot  47  being accessible through an axial passage  48  in the end cap  27 .

Technology Classification (CPC): 6