Refrigeration modulating valve sealing device

A sealing device for a modulating valve of the type having a valve body defining a flow passage, an inlet and outlets, a valve displaceable in the flow passage, and an actuator having an actuator rod rotatably coupled to the valve for displacing the valve in the flow passage. The sealing device comprises a body surrounding the actuator rod. A connector is adapted to secure the body of the sealing device to the valve body. Seals are provided between the body of the sealing device and the actuator rod arid between the body of the sealing device and the valve body, to prevent fluid flow therebetween. The body of the sealing device and the seals are adapted to conceal and contain fluid leaks, whereby no fluid is lost due to a leaking modulating valve.

TECHNICAL FIELD

The present invention generally relates to modulating valves used in refrigerant circuits and, more particularly, to a sealing device for preventing refrigerant losses through leaks of modulating valves.

BACKGROUND ART

Various types of modulating valves, such as incrementally positionable valves, are widely used in refrigerant circuits for refrigeration and air-conditioning systems. For instance, modulating valves are frequently used at nodes of diverging loops of circuits to provide refrigerant for heat reclaim or for defrosting evaporators of refrigeration display units. Such valves are also used in split condensers and hot-gas applications. These valves are used to control the ratios of refrigerant conveyed to the various elements of the circuits or to control the flow of refrigerant through the lines. The modulating action of the valves prevents water hammer in the refrigerant lines, which could have adverse effects on the various elements of such circuits. Mueller™ Refrigeration Co. provides such modulating valves, under the name Cycle Master™.

However, the modulating valves of refrigerant circuits are subjected to the harsh conditions typical to circuits. For instance, the refrigerant in refrigerant circuits is at relatively high temperatures and fluctuates between large temperature variations. Furthermore, the refrigerant is compressed to relatively high pressures, and the modulating valves are often employed to create pressure drops in the circuits. Finally, the refrigerants typically known and used are often of a corrosive nature.

For these reasons, some modulating valves have been known to leak at the stem. A plurality of negative effects results from such leaks. For instance, substantial losses of refrigerant can cause inefficient refrigeration cycles and shutdowns. Furthermore, the refrigerants are often harmful to the environment, and refrigerant losses to the environment must be prevented. Finally, downtimes are very costly and are risky as the contents of the refrigeration display units cannot be subjected to temperature increases without the risk of being fouled.

SUMMARY OF INVENTION

It is a feature of the present invention to provide a sealing device for preventing refrigerant loss through a modulating valve.

According to the above features of the present invention, from a broad aspect, the present invention provides a sealing device for a modulating valve of the type having a valve body defining a flow passage, at least one inlet and one outlet, a valve displaceable in the flow passage to control an opening of the flow passage, and actuation means having an actuator rod rotatably coupled to the valve at an exterior of the valve body for displacing the valve in the flow passage, the sealing device comprising a body surrounding the actuator rod of the modulating valve, the body defining a receptacle for accommodating a coupling between the actuator rod and the valve so as not to impede on the actuation of the valve by the actuator rod; connection means adapted to secure the body of the sealing device to the valve body, the connection means being a tubular member being adapted to be threadingly engaged to the valve body, the tubular member compressing the body of the sealing device against the valve body such that a first one of the sealing means is squeezed between the body of the sealing device and the valve body; and sealing means between the body of the sealing device and the actuator rod and between the body of the sealing device and the valve body, to prevent fluid flow therebetween, said body of the sealing device and said sealing means being adapted to conceal and contain fluid leaks between one of the valve and the actuator rod, and the valve body, whereby no fluid is lost due to a leaking modulating valve.

Further in accordance with the present invention, there is provided a sealing device for a modulating valve of the type having a valve body defining a flow passage, at least one inlet and one outlet, a valve displaceable in the flow passage to control an opening of the flow passage, and actuation means having an actuator rod rotatably coupled to the valve at an exterior of the valve body for displacing the valve in the flow passage, the sealing device comprising a body surrounding the actuator rod of the modulating valve, the body defining a receptacle for accommodating a coupling between the actuator rod and the valve so as not to impede on the actuation of the valve by the actuator rod; connection means adapted to secure the body of the sealing device to the valve body; sealing means between the body of the sealing device and the actuator rod and between the body of the sealing device and the valve body, with the sealing means between the, body of the sealing device and the rod being packing, to prevent fluid flow therebetween, said body of the sealing device and said sealing means being adapted to conceal and contain fluid leaks between one of the valve and the actuator rod, and the valve body, whereby no fluid is lost due to a leaking modulating valve; and a cover member connectable to an end of the body of the sealing device distal from the valve body, the cover member having a sleeve accommodatable between the body of the sealing device and the actuator rod to contain the packing therebetween.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the drawings, and more particularly toFIG. 1, a modulating valve is generally shown at10. The modulating valve10is of the three-way type, and has an inlet12and outlets14and16. The modulating valve10has an actuator stem18protruding outwardly from a connection collar20. The actuator stem18is connected to a ball (not shown) in the modulating valve10, and is actuated to control the position of the ball in the modulating valve10. For instance, a modulating action on the actuator stem18can be performed to control the outputs of the outlets14and16with respect to one another, or to create a pressure differential between the inlet12and the outlets14and16. The connection collar20has a threaded peripheral surface21.

The actuator stem18is actuated by an actuator22connected to the actuator stem18by an actuation rod24. As shown inFIGS. 1 and 2, the actuation rod24has a head portion25having a mating hole27, to be rotatably coupled to the actuator stem18. Returning toFIG. 1, the actuator22is mounted to the body of the modulating valve10by a support bracket26. The support bracket26has a first leg28riding on the outlet pipe14of the modulating valve and a second leg30secured to the connection collar20by a pair of fasteners32, which are operatively engaged to the threaded peripheral surface21. The actuator22is typically a Belimo™ or a Neptroric™ motor, whereas the modulating valve10is, for instance, a Mueller™ Refrigeration Cycle Master™ valve. Stops34(only one of which is shown) are provided on a top annular surface36of the connection collar20, and coact with a radial pin (not shown) on the actuator stem18to typically limit the angular displacement of the ball to 90°.

Leaks have been known to occur between the actuator stem18and the connection collar20. Therefore, a sealing device in accordance with the present invention is generally shown at40, and is mounted to the modulating valve10so as to prevent losses of refrigerant from the modulating valve10.

The sealing device40, as best shown inFIGS. 2 and 3, has a tube portion42, a connector portion44, actuation rod seals46and a valve seal48. The tube portion42is shown having a tubular body50having a top end51, a bottom end52, and an outer peripheral surface53with a shoulder54, generally in a middle area of the tubular body50. The tubular body50has a through bore56and a first counterbore58concentric with the through bore56. A second counterbore60of larger diameter is concentric with the first counterbore58. Three radial grooves62are positioned in the through bore56and are adapted to each receive one of the actuation rod seals46. The seals46are typically of materials well suited for high-temperature refrigerant. For instance, the seals46can be in neoprene, nitrile, polytetrafluoroethylene (PTFE), Hypalon™, or any other material well suited for the applications of the modulating valve10, and may be lip seals, O-rings or any other suitable type of seal. An annular groove64is positioned on the bottom end52of the tubular body50, and receives therein the valve seal48. Similarly to the actuation rod seals46, the valve seal48is made of materials well suited for refrigerant at high temperatures, such as neoprene, nitrile, PTFE, Hypalon™, etc., and can be a lip seal, an O-ring, etc.

The connector portion44has a tubular body66having a top end68, a bottom end70, and a through bore72. An inner lip74projects radially inwardly in the through bore72at the top end68of the tubular body66. The tubular body66is tapped at the bottom end70.

Now that the various elements of the sealing device40have been described in detail, the assembly of the sealing device40to the modulating valve10will be described. Prior to the actuator22being mounted to the modulating valve10, the tube portion42of the sealing device40is axially slid onto the actuation rod24. The tube portion42is sized such that the first counterbore58thereof snugly receives the head portion25of the actuation rod24. In doing so, the actuation rod seals46seal the passage between the through bore56of the tube portion42and the actuation rod24.

The tube portion42is positioned on the top annular surface36of the connection collar20, with the bottom end52of the tube portion42sitting thereon. Accordingly, the valve seal48seals the tube portion42to the connection collar20. In positioning the actuation rod24on the connection collar20, the mating hole27is rotatably coupled to the actuation stem18. The actuation rod24is free to rotate with respect to the tube portion42. The second counterbore60accommodates the stops34and the radial pin (not shown) of the actuator stem18. The radial pin is free to move in the second counterbore60.

Thereafter, the connector portion44is threadingly engaged through its tapped portion at the bottom end70thereof to the threaded peripheral surface21of the connection collar20. The connector portion44is sized so as to snugly receive a bottom portion of the tube portion42. More precisely, the inner lip74of the connector portion44abuts against the shoulder54on the peripheral surface53of the tube portion42. Therefore, as the connector portion44is tightened onto the connection collar20, the tube portion42is pulled downwardly so as to squeeze the valve seal48, thereby securing the sealing therebetween.

It is pointed out that the fasteners32must be engaged on the connection collar20prior to the connector portion44being secured thereto. Furthermore, the second leg30of the support bracket26may be secured to the modulating valve10in a first step, to then have the second leg30and the remainder of the support bracket26added thereto via bolt and nut38, once the sealing device40has been mounted onto the modulating valve10. The sealing device40does not prevent leaks between the actuator stem18and the connection collar20. However, refrigerant leaks therethrough are concealed and contained by the sealing device40such that no refrigerant is lost because of a leaking modulating valve.

The modulating valves10can be retrofitted with the sealing device40. Therefore, the sealing device40may be sold separately from the modulating valve10as a repair kit. The installation of the sealing device40on the modulating valve10is readily achieved, whereby the downtime for attending to the modulating valve10in case of a leak is greatly reduced.

Referring now toFIGS. 4,5and6, a second embodiment of the present invention is shown, in which packing is used instead of the seals46to seal the actuation rod24. The sealing device in accordance with the second embodiment of the present invention is generally shown at40′. For clarity purposes, like elements between the first embodiment ofFIGS. 1to3and the second embodiment ofFIGS. 4to6will bear the same reference numerals. Additional elements will have their reference numerals primed. As best seen inFIG. 5, the sealing device40′ has a tube portion42′, the connector portion44, packing46′, the valve seal48and a packing retainer49′.

Referring toFIG. 6, the tube portion42′ is relatively similar to the tube portion42of FIG.3. However, in addition to the tubular body50having the top end51and the bottom end52, the peripheral surface53, the shoulder54, the through bore56, the first counterbore58, and the second counterbore60, the tube portion42′ has a third counterbore61′ concentric with the through bore56and extending therein from the top end51of the tube portion42′. Furthermore, a second annular groove65′ is defined at the top end68of the tube portion42′. An upper portion of the peripheral surface53is threaded.

Still referring toFIG. 6, the packing retainer49′ is shown having a first tubular body80and a second tubular body82. The second tubular body82is concentrically disposed with respect to the first tubular body80. The first tubular body80and the second tubular body82share a top end84. However, the second tubular body82is shorter than the first tubular body80. An underside86of the top end84defines an annular protrusion88. The first tubular body80is tapped, so as to threadingly engage with the threads on the upper portion of the peripheral surface53of the tube portion42′.

The sealing device40′ is mounted to the modulating valve10by the connector portion44, as described for the first embodiments ofFIGS. 1to3. However, the sealing of the actuation rod24is performed by putting packing46′ into the third counterbore of the tube portion42′. Thereafter, the packing retainer)49′ is screwed onto the tube portion42′, and the second tubular portion82compresses the packing46′ so as to ensure the integrity of the sealing between the actuation rod24and the tube portion42′. The annular protrusion88ensures the precise positioning of the packing retainer49′ on the tube portion42′ by nesting into the second annular groove65′. Various types of packing46′ may be used, such as carbon/graphite packing, synthetic braids coated with PTFE, PTFE or other similar materials.

It is within the ambit of the present invention to cover any obvious modifications of the embodiments described herein, provided such modifications fall within the scope of the appended claims.