Abstract:
A shut-off valve for pressurized fluids in an air cooling/heating apparatus having a first duct receiving a first restrictor and a second restrictor. Both restrictors are coaxially formed with a capillary through which the pressurized fluid passes and which causes the rapid expansion of the fluid when the fluid exits from a distal end of the capillary. The outer surface of the restrictors is in direct contact with the interior surface of the first duct. The valve can further include a sampling instrument located between the restrictors.

Description:
RELATED CASES 
   The present application claims priority to U.S. Patent Application Ser. No. 60/524,145, filed Nov. 21, 2003, the disclosure of which is expressly incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to a shut-off valve for pressurized fluids in an air cooling/heating system such as air conditioners and the like. 
   BACKGROUND OF THE INVENTION 
   It is known in the art of air conditioners and heat pumps that a condenser and an evaporator must be placed in communication with each other by means of shut-off valves and other devices designed to cause expansion of the refrigerant as the refrigerant flows from one component to another. 
   Specifically, in refrigerant systems operating in both the cooling and heating modes, two expansion devices may be incorporated into one system allowing for expansion of the fluid in either direction. A shut-off valve may also be incorporated into a system when there is a need to terminate refrigerant flow, such as for example, during servicing. The refrigerant system may also include a sampling port for detecting and measuring the pressure of the high-pressure refrigerant before the refrigerant enters the expansion device. Furthermore, the ability to easily interchange the expansion devices allows the degree of expansion to be selectively varied after installation of the shut-off valve. 
   Combining the shut-off valve, expansion devices and sampling device into one unit is desirable to reduce the complexity of a refrigerant system. However, known refrigerant systems lack a mechanism for sampling the liquid refrigerant before the liquid enters the expansion devices in both the cooling and heating modes. Therefore, a need exists for a shut-off valve that allows for sampling high-pressure liquid between two expansion devices. 
   Prior art dual restrictors utilize a labor intensive process of manually torch brazing the connecting tube to the shut-off valve body in order to protect expansion devices integrated within the body. It is desired to use a more cost efficient process of furnace brazing the tube onto the valve body. Therefore, a need exists for a shut-off valve having integrated expansion devices which will not be adversely affected by the furnace brazing process. 
   SUMMARY OF THE INVENTION 
   The present invention resolves the above noted problem by providing a shut-off valve for pressurized fluid in an air cooling/heating apparatus having a first duct that receives a first restrictor and a second restrictor. Both of the restrictors are coaxially formed with a capillary through which the pressurized fluid passes and which causes rapid expansion of the fluid when the fluid exits from a distal end of the capillary. The outer surface of the restrictors is in direct contact with the interior surface of the first duct. 
   A feature of the above noted valve has the valve including a sampling instrument, located between the restrictors, for sampling fluid. Another feature of the above noted valve has both of the restrictors being capable of independent axial movement within the first duct. A further feature of the noted valve has an outer portion of each restrictor being formed with at least two radial fins that cooperate with interior surfaces of the first duct to create at least one flow channel for fluid flow. 
   Still another feature of the noted valve has the first restrictor being fixed within the first duct and having a longitudinal end with a conical surface in sealing contact with a flared connecting pipe. The second restrictor having an outer portion formed with at least two radial fins cooperating with the interior surface of the first duct to create at least one flow channel for fluid flow. The second restrictor being axially movable from a first position in which a sealing member of the second restrictor is in sealing contact with a shoulder formed within the first duct to a second position in which the second restrictor is in contact with the first restrictor. A further feature of this noted valve has, when the second restrictor is in the second position, fluid flow being directed entirely through the capillary. 
   Yet another feature of the noted valve has the restrictors being removable from the duct and the valve. Still another feature of the noted valve has the restrictors being replaceable. 
   Still yet another feature of the present invention has the shut-off valve being in communication with at least one condenser and at least one fluid evaporator and having the first duct being in communication with the evaporator. The valve will further include a second duct in communication with the condenser and a third duct. The first duct receives a first restrictor and a second restrictor which are both coaxially formed with a capillary through which fluid passes and which cause rapid expansion of the fluid when the fluid exits from a distal end of the capillary. The outer surface of the restrictors is in direct contact with the interior surface of the first duct. 
   Another attribute of the noted valve has at least the second restrictor being capable of independent axial movement within the first duct. Still another attribute of the noted valve has the first restrictor clamping an end of a pipe directly against a surface of the first restrictor. Yet another attribute has the first restrictor selectively secured to the first duct by threaded engagement. Still another feature has the third duct receiving an instrument for sampling fluid in the valve. Another feature has the third duct located intermediate the first and second ducts, such that the fluid sampling instrument can sample fluid prior to the fluid passing through a restrictor when the air cooling/heating apparatus is in one mode of operation. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features and inventive aspects of the present invention will become more apparent upon reading the following detailed description, claims, and drawings, of which the following is a brief description: 
       FIG. 1  is a sectioned view of a shut-off valve according to the present invention; 
       FIG. 2  is a sectioned view of a prior art shut-off valve; 
       FIG. 3  is a sectioned exploded view of the shut-off valve shown in  FIG. 1 ; 
       FIG. 4  is a partially sectioned view of the shut-off valve operating in the cooling mode; and 
       FIG. 5  is a partially sectioned view of a further embodiment shut-off valve according to the present invention. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Referring to  FIGS. 1 and 3 , an embodiment of a shut-off valve  10  in accordance with the principles of the current invention is shown. Shut-off valve  10  includes a body  12  that has at least two ducts formed there through. A first duct  14  communicates with an evaporator (not illustrated). A second duct  16  communicates with a condenser (not illustrated). Preferably, valve body  12  includes a third duct  18  that is adapted to receive a sampling mechanism  20  for allowing the detection and measurement of the fluid pressure between ducts  14 ,  16  and  18 , to be explained in further detail below. As will be discussed below, shut-off valve  10  allows an enduser to replace (or switch out) restrictors that typically are permanently installed within the shut-off valve. The present invention also provides a poke-yoke methodology, as shown in U.S. Pat. No. 6,546,952 to Martin et al., assigned to the assignee of the present invention and herein incorporated by reference. This ensures the proper installation of the restrictors when replacing the restrictor in the field, as well as in production assembly. Further, shut-off valve  10  has a reduced manufacturing cost with fewer components than in the prior art. 
   Valve  10  further includes an obturator  22  that may be displaced by rotation between a closed position in which fluid flow between first duct  14  and second duct  16  is blocked (not shown) and an open position in which flow between first duct  14  and second duct  16  is permitted (shown as open in  FIG. 1 ). As seen in  FIG. 3 , first duct  14 , that is in communication with the evaporator, is formed inside a first outlet  24  of body  12  with an external thread  26  located on body  12 . Outlet  24  has positioned therein two coaxial seats  28  and  32 . Coaxial seats  28  and  32  receive and house a restrictor  34  and a flared restrictor  30  respectively. The inside diameter of each coaxial seat  28  and  32  is slightly larger than the outside diameter of restrictors  34 ,  30  respectively, such that restrictor  34  and flared restrictor  30  are slidably assembled in their respective seats without interference. The outer surface of restrictors  30 ,  34  are in direct contact with seats  32 ,  28  respectively, thus minimizing the number of components of valve  10 . Stated another way, the outer surface of restrictors  30 ,  34  are in direct contact with the defining surface of duct  14 . 
   Restrictor  34  is formed with an axial capillary duct  46  with a predetermined diameter that corresponds to the desired degree of expansion of the fluid. Restrictor  34  is provided with a plurality of radial fins  47  that cooperate with seat  28  to create a plurality of flow channels for the free flow of fluid. A void  54 , (best seen in  FIG. 1 ) defined between an axial surface  56  of flared restrictor  30  and a shoulder  58  of seat  28 , allows for a limited degree of axial movement of restrictor  34 . A frontal projection  48  is designed to cooperate with shoulder  58  of seat  28  in order to limit axial movement of restrictor  34  in a direction towards obturator  22 . Specifically, frontal projection  48  has a radial sealing member  66  that sealingly contacts shoulder  58 . Similarly, axial surface  56  of flared restrictor  30  is designed to cooperate with a rear axial surface  60  of restrictor  34  to limit axial movement of restrictor  34  in a direction toward a connecting pipe  62 . 
   Flared restrictor  30  has an end portion  64  received within outlet  24 . A cylindrical portion  68  of restrictor  30  engages seat  32  in outlet  24  so as to provide a seal to prevent the passage of fluid. Preferably, cylindrical portion  68  of flared restrictor  30  is also formed with an annular seat  70  housing an annular sealing element  72  such as an O-ring. Flared restrictor  30  further includes a conical surface  73  designed to cooperate with a flared end  74  of connecting pipe  62  to ensure a seal. Flared restrictor  30  can only be received, or housed, within duct  14  with its conical surface  73  towards connecting pipe  62 . This ensures a correct orientation and assembly of restrictor  30 . Restrictor  30  is preferably retained in seat  32  by a nut  76  that can be tightened on external thread  26  of outlet  24 . An internal conical surface  78  of nut  76  acts against flared end  74  of connecting pipe  62  forming a seal between connecting pipe  62  and flared restrictor  30 . Restrictor  30  is formed with an axial capillary duct  42  with a predetermined diameter that corresponds to the desired degree of expansion of the fluid. 
   Second duct  16 , in communication with the condenser (not shown), is formed inside a second outlet  80  of body  12 . Outlet  80  has formed therein an internal conical seat  84  that receives and houses a filtering element  90 . Filtering element  90  is retained in seat  84  by a second connecting pipe  86  that abuts a shoulder  88  created between seat  84  and a seat  82 . Connecting pipe  86  is retained in seat  82  and is fixedly attached to valve body  12  preferably by brazing connecting pipe  86  to outlet  80 . However other suitable methods of attaching connecting pipe  86  and outlet  80  may also be employed. 
   Referring to  FIGS. 1 and 3 , during operation in the heating mode, fluid flows through valve  10  from connecting pipe  62  to connecting pipe  86 , first passing through restrictor  30 . The pressure of the fluid itself produces axial movement of restrictor  34  away from pipe  62  thus causing seal  66  to sealingly abut shoulder  58 . In this configuration, the fluid from pipe  62  must flow only through capillary duct  46 , and not around restrictor  34 . When obturator  22  is in the open position, fluid may freely flow from first duct  14  into second duct  16 . The fluid, in order for it to pass through restrictor  34 , is channeled into capillary duct  46  causing expansion of the fluid as it exits capillary duct  46 . The expanded fluid then exits valve  10  through a filtering element  90  and proceeds into pipe  86 , which is affixed to body  12  at outlet  80 . It should be noted that since the fluid is passing through two capillary ducts  42 ,  46 , it is advantageous to have the diameter of capillary duct  46  be smaller than that of duct  42  so that restriction properly occurs. Of course, an enduser can freely replace (or switch) restrictors  30 ,  34  with restrictors having any orifice size. 
   Operation occurs in a substantially similar manner, but in the opposite direction, during operation of the valve in the cooling mode as illustrated in  FIG. 4 . During operation in the cooling mode, fluid enters outlet  80  through pipe  86  and flows through filtering element  90 . When obturator  22  is in the open position (as is shown in  FIG. 4 ), fluid travels from duct  16  into duct  14  such that fluid pressure produces movement in restrictor  34  towards connecting pipe  62  to open fluid flow around restrictor  34 , or through radial fins  47 . In this configuration, the fluid is able to flow freely until it encounters restrictor  30  where it is channeled through capillary  42  causing expansion of the fluid as the fluid exits capillary duct  42  through connecting pipe  62 . 
   In operation, fluid flows through valve  10  from pipe  62  to pipe  86  in the heating mode and from pipe  86  to pipe  62  in the cooling mode. In the heating mode, fluid flows through restrictor axial capillary duct  46  into duct  14 . When the obturator  22  is in the open position, the fluid is then free to flow into duct  16  and duct  18 . As discussed above, with valve  10 , in the heating mode the flow is directed towards the smaller orifice within restrictor  34 . In contrast to this, for typical cooling modes the line set connection, or pipe  62 , to the metering device, or restrictor  30  needs to be longer in length, therefore a larger diameter orifice is needed. This will provide greater pressure to compensate for the pressure loss in the cooling mode because of the length of metering to the evaporator coil is greater than of the heat pump mode. During the cooling mode, when obturator  22  is in the open position, fluid is free to flow from duct  16  into duct  18  so that the fluid pressure may be detected and measured via sampling mechanism  20 . It should be noted that in addition to sampling, duct  18  is used as a charge port in both the heating and cooling modes. 
   Referring to  FIGS. 1 and 2 , the present design reduces manufacturing cost by eliminating the need to press seat a prior art fitting  94  (as shown in  FIG. 2 ), as well as significantly reducing the amount of components. Present invention restrictor  30  has been incorporate/combined with a flared adapter  36  (shown in  FIG. 2 ). This reduces the number of parts when compared with a prior art shut-off valve  50 . It should be noted that in addition to its metering (restriction) utility, restrictor  30  is now also used as the line set connection (which receives connecting pipe  62 ). Prior art shut-off valve  50  has a restrictor  52  encapsulated within a valve body  51  prior to a copper tube  96  being inserted into and permanently affixed with body  51 . Copper tube  96  must then be manually torched brazed for connection to the system unit, which is an expensive process. A commonly used furnace brazing process is desired but can not be utilized in this prior art embodiment since the furnace brazing process exhibits too much heat which can cause restrictor  52  to fuse to valve body  51 . Therefore the manually torch brazing technique needs to be used. By moving this restrictor to the field side (as is shown as restrictor  30  in  FIG. 1 ), the more cost efficient furnace brazing technique can be used to attach pipe  86  in the present invention. 
   A flared connection  74  is advantageous because the connection can be easily disassembled allowing the substitution of restrictors. The ability to interchange a restrictor allows the shutoff valve to be field serviced without the need for complex brazing operations. Furthermore, restrictors with different capillary diameters may be employed such that the degree of expansion may be selectively varied. An end-user can replace or switch-out restrictors ( 30 ,  34 ) from the field connection end (located at connecting pipe  62 ). In the prior art (as shown in  FIG. 2 ), since copper tube  96  is permanently brazed in place, restrictor  52  can not be replaced or switched. It is common for an end-user to change restrictors either for service reasons or to ensure that the proper sized orifice is used during its application. For example, if an application requires capillary duct  42  of restrictor  30  to be larger than capillary duct  46  of restrictor  34 , the present invention allows an end-user to be able to use the proper restrictors for this application without replacing the entire shut-off valve. The present invention gives the end-user this flexibility so that flow during the heating and cooling cycles is most efficient. 
     FIG. 5  shows a further embodiment shut-off valve  110  according to the present invention. The majority of the components shown in  FIG. 5  are similar to that shown in  FIG. 1  and will use the same element numbers. Similar to shut-off valve  10  (detailed above), valve  110  has a body  12  with at least two ducts formed therein. Again, a first duct  14  communicates with an evaporator (not illustrated) and a second duct  16  communicates with a condenser (not illustrated). Valve  110  has removed restrictor  40 , shown in  FIG. 1 , and replaced it with a restrictor  140  which can move axially (similar to restrictor  34 ). Also similar to restrictor  34 , restrictor  140  has an axial capillary duct  142  with a predetermined diameter that corresponds to the desired degree of expansion of the fluid. Restrictor  140  is provided with a plurality of radial fins  165  that cooperate with seat  28  to create a plurality of flow channels for the free flow of fluid. Restrictor  140  can axially move between insert member and a spacer  153 . A frontal projection  167  is designed to cooperate with a shoulder  164  of an insert member  138  in order to limit axial movement of restrictor  140 . Specifically, frontal projection  167  has a radial sealing member  141  that sealingly contacts shoulder  164 . 
   Valve  110  has also provided a sampling instrument  155  that can measure the pressure within duct  14  in both the heating and cooling modes. With valve  10  (shown in  FIG. 1 ), the pressure measurement, as well as the charging operation, was conducted within duct  18  by sampling mechanism  20 . The sampling function with valve  110  has been moved to duct  14 . However, the charging operation still takes place within duct  18  with a charging valve  121 . By integrating the sampling function within duct  14 , pressure can now be measured in both the heating and cooling modes. As is well known in the art, unrestricted fluid can be sampled. Therefore there must be a free flow of fluid at the sampling location. 
   During the heating mode operation, fluid enters shut-off valve  110  from tube  62  attached to insert member  138 . The fluid will pass through insert member  138  and move restrictor  140  to the right until it contacts spacer  153 . Due to the axial passages through radial fins  165 , fluid is not impeded when passing restrictor  140 . The free flow of fluid can be sampled by sampling instrument  155  before reaching restrictor  34 . The free flow of fluid moves restrictor  34  to the right and into sealing contact with shoulder  58 , causing all fluid to pass through axial capillary duct  46 . As discussed above, this causes the desired restriction of the fluid in the heating mode. During the cooling mode operation, fluid enters shut-off valve  110  through connecting pipe  86  and into ducts  16  and  14 . Fluid causes restrictor  34  to move to the left and into contact with spacer  153 . In this position and due to the axial passages through radial fins  47 , fluid is not impeded by restrictor  34 . The free flow of fluid can be sampled by sampling instrument  155  before reaching restrictor  140 . The fluid then causes restrictor  140  to move to the left and into contact with insert member shoulder  164 . In this position, fluid can only pass through axial capillary duct  142  and is properly restricted. As discussed with valve  10 , proper sampling can take place during the heating and cooling modes when obturator  22  is in the open position. 
   This embodiment provides less restriction of the fluid in the heating mode and allows for sampling. As described above and shown with valve  10  in  FIG. 1 , restrictor  30  does not axially move. With shut-off valve  10 , fluid passes through axial capillary duct  42  both in the heating and cooling operations even though restriction is only needed with capillary duct  46  in the heating mode. With valve  110 , fluid is only restricted by one capillary duct (or restrictor orifice)  142 ,  46  in both the heating and cooling operation since both restrictors now axially oscillate. This embodiment still provides the option of switching (or replacing) restrictors  140 ,  34  since first duct  14  is accessible through the field connection end of shut-off valve  110 . Again, valve  110  has simplified the number of components so that replacement of restrictors is an easy task and enables an enduser to sample the fluid in both the heating and cooling modes. 
   Preferred embodiments of the present invention have been disclosed. A person of ordinary skill in the art would realize, however, that certain modifications would come within the teachings of this invention. Therefore, the following claims should be studied to determine the true scope and content of the invention.