CN107850065B

CN107850065B - Ventilating type discharge valve of reciprocating compressor

Info

Publication number: CN107850065B
Application number: CN201680046091.XA
Authority: CN
Inventors: P.J.弗拉尼根
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2015-08-26
Filing date: 2016-08-25
Publication date: 2021-02-19
Anticipated expiration: 2036-08-25
Also published as: CN107850065A; EP3341611A1; EP3341611B1; WO2017035289A1; US20180209407A1; ES2830038T3

Abstract

The invention provides a compressor (20) comprising: a housing (22); and at least one piston (40) mounted for reciprocating movement, each piston being in a respective cylinder (42) of the housing. The at least one piston has a circumferential surface (50) and an upper surface (52). The at least one discharge valve comprises: a valve element (150) movable between a closed state and an open state; a valve guide (170); one or more springs (180) at least partially retained by the valve guide to bias the valve element from the open state toward the closed state; and one or more vents (300) in the valve guide providing a flow path from an area above the valve element up through the valve guide.

Description

Ventilating type discharge valve of reciprocating compressor

Cross Reference to Related Applications

The benefit of U.S. patent application serial No. 62/210,105, filed on 16/8/2015 and entitled "stabilizing Compressor held Discharge Valve," the disclosure of which is incorporated by reference herein in its entirety as if fully set forth.

Background

The present disclosure relates to a reciprocating compressor. More particularly, the present disclosure relates to a discharge valve.

Reciprocating compressors have long been used in applications such as refrigeration. One recent arrangement involves a piston having an upper surface with a protrusion that protrudes above the top surface of the cylinder block at a top-dead-center (top-center) to facilitate complete filling of the volume within the valve plate to provide a more complete discharge of the compressed fluid.

Disclosure of Invention

One aspect of the present disclosure relates to a compressor, including: a housing; and at least one piston mounted for reciprocating movement, each piston in a respective cylinder of the housing, the at least one piston having a circumferential surface and an upper surface. The at least one discharge valve comprises: a valve element movable between a closed state and an open state; a valve guide; one or more springs at least partially retained by the valve guide to bias the valve element from the open state toward the closed state; and one or more vents in the valve guide providing a flow path from the area above the valve element up through the valve guide.

In one or more embodiments of any of the preceding embodiments, the one or more springs are a plurality of coil springs.

In one or more embodiments of any of the preceding embodiments, the one or more springs are eight to sixteen springs/cylinder.

In one or more embodiments of any of the preceding embodiments, the one or more springs are partially housed in the one or more sockets and the one or more vents extend to the one or more spring sockets.

In one or more embodiments of any of the preceding embodiments, each of the one or more vents is coaxial with a respective associated one of the one or more sockets.

In one or more embodiments of any of the preceding embodiments, the valve element is an annular element.

In one or more embodiments of any of the preceding embodiments, the one or more circumferential openings provide communication from the cylinder to the exhaust plenum.

In one or more embodiments of any of the preceding embodiments, the compressor further comprises: a motor; a crankshaft driven by a motor; and at least one connecting rod coupling the crankshaft to the at least one piston.

In one or more embodiments of any of the preceding embodiments, the one or more vents each comprise a bore.

In one or more of any of the preceding embodiments, the at least one piston comprises a plurality of identical pistons.

In one or more embodiments of any of the preceding embodiments, the cylinder is formed in a cylinder block; a valve plate assembly mounted to the cylinder block; and the valve guide is mounted to the valve plate assembly.

In one or more embodiments of any of the preceding embodiments, the valve plate assembly has a valve seat forming a seating surface of the suction valve; the piston upper surface has an outer portion and a projection extending centrally upwardly; and the piston has a top dead center condition wherein the protrusion is partially received within the valve seat.

In one or more of any of the preceding embodiments, the valve seat forms an outer seating surface of the discharge valve; the valve plate assembly has an inner valve seat forming an inner seating surface of the discharge valve; the piston has a recess in the projection; and in a top dead center condition, the inner valve seat is partially received within the recess.

In one or more of any of the preceding embodiments, the method for manufacturing a compressor includes drilling to form the at least one vent.

In one or more of any of the preceding embodiments, the method for using a compressor includes reciprocating a piston in a cylinder, a fluid flow passing through at least one vent during an upward portion of the reciprocating motion.

In one or more embodiments of any of the preceding embodiments, the fluid flow is a branch of the flow exiting the cylinder, and another branch exits from the circumferential opening.

In one or more embodiments of any of the preceding embodiments, the vapor compression system comprises a compressor.

In one or more embodiments of any of the preceding embodiments, the vapor compression system is a refrigeration system.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

Brief Description of Drawings

Fig. 1 is a longitudinal sectional view of a compressor.

Fig. 1A is an enlarged view of the first two cylinders of the compressor of fig. 1.

Fig. 1B is an enlarged view of a portion of the foremost cylinder of the compressor of fig. 1.

Fig. 2 is an isolated view of a piston of the compressor of fig. 1.

Fig. 3 is an exploded sectional view of a single cylinder of the compressor.

Like reference numbers and designations in the various drawings indicate like elements.

Detailed Description

Fig. 1 shows a compressor 20. The compressor has a shell or housing assembly 22 that includes an inlet or suction port 24 and an outlet or discharge port 26. The exemplary compressor includes an electric motor 28 that includes a stator 32 and a rotor 30. Rotor 30 is integrated with crankshaft 34 to drive the crankshaft for rotation about axis 500. The crankshaft is supported for rotation about axis 500 by a plurality of bearings. The compressor is a reciprocating compressor having a plurality of pistons 40 mounted for reciprocating movement in respective associated cylinders 42 defined within a cylinder block 44 of the housing. The exemplary cylinder is coupled to the crankshaft via a wrist pin 46 carried by the piston and a connecting rod 48 coupling the wrist pin to the crankshaft.

Each piston has a lateral or side or Outer Diameter (OD) surface 50 (fig. 1A) and an upper or top surface 52. Fig. 1A shows the forwardmost piston in a Top Dead Center (TDC) position. At the TDC position, the lateral portion 54 of the upper surface 52 is substantially flush with the upper surface 60 of the cylinder block 44. A valve plate assembly 70 is mounted atop surface 60 (with interposition of gasket 62) and supports a valve assembly 72 associated with the respective cylinder. As discussed further below, the valve assemblies 72 each include a portion that forms an inlet or suction valve and a portion that forms a discharge or outlet valve. A cylinder head 74 is mounted atop the valve plate assembly (with the interposition of a gasket 75) and encloses a discharge plenum 76 that communicates with the discharge port 26.

Fig. 1A further illustrates a piston including an upward projection 80 (having a lateral or side surface or Outer Diameter (OD) surface 82 and an upper or distal end 84) representing a top dead center condition or position in the forwardmost piston projecting into the valve plate assembly 70. This helps to minimize headspace at top dead center conditions for improved overall flow.

Exemplary valve plate assembly 70 includes a bottom plate 90 and a top plate 92 separated by a spacer. The spacer may include a peripheral plate 94 that cooperates with the periphery of the valve plate assembly to close a plenum 96. Additional spacers 98 may be distributed within the plenum. As discussed further below, plenum 96 is a suction plenum that communicates with suction port 24. For example, with the suction inlet 24 in a motor housing section of the housing assembly, the suction plenum 96 may communicate with the interior of the motor housing via a passage (not shown) cast in the housing assembly.

The suction valve includes a flexible valve element 120 (fig. 1B) mounted between the valve plate assembly 70 and the cylinder block 44 in the circumferential direction of each cylinder 42. The valve element 120 is formed as a sheet having a lower surface 122 and an upper surface 124. At each cylinder, the valve element has a central bore defined by an inner peripheral (inner diameter (ID)) surface 126. In the closed state, the upper surface 124 adjacent the inner perimeter 126 seats against a seating surface 130 (ID valve seat). The example seating surface 130 is a lower surface of a valve seat 132, the upper surface of which forms a discharge valve seating surface as discussed further below. The Inner Diameter (ID) surface 134 of the valve seat closely conforms to the OD surface 82 of the protrusion 80 in the top dead center condition. The OD seating surface may be formed by a portion of the underside of the bottom plate 90.

The exemplary suction valve member is generally circular but has two tabs 135 (fig. 3) spaced 180 ° apart that rest on the crankcase platform for support; and two tabs 136 that act as stops.

The example valve seat 132 includes an upper portion that is mounted to the top plate 92 (e.g., via a press-fit, brazing, etc.); and a lower portion depending through the plenum 96 and through an associated aperture 140 in the base plate 90. In operation, as the piston retracts from its top dead centre condition, the reduced pressure/suction causes the valve element 120 to flex, i.e. to be bent in the middle (like a U) and supported by two tabs 135 at the edges of the cylinder bore and to be blocked by the engagement of the tabs 136 with complementary associated surfaces of the recess in the cylinder. This downward flexing disengages the elements from the ID and OD valve seat surfaces to allow refrigerant to be drawn into the cylinder from the suction plenum 96 via the ports 148 (the annular peripheral portion of the aperture 140 is radially outward of the Outer Diameter (OD) surface of the lower portion of the valve seat 132). After the piston bottoms out and reverses direction, the valve member 120 folds back to its closed or sealed state, engaging the seating surface to close the port 148.

The discharge valve may similarly include a valve element 150 (fig. 1B) having an open state and a closed state. The example valve element 150 is a spring-loaded annulus having a lower surface 152, an upper surface 154, an Inner Diameter (ID) peripheral surface 156, and an Outer Diameter (OD) peripheral surface 158. Exemplary valve seats for valves include an Inner Diameter (ID) valve seat and an Outer Diameter (OD) valve seat. The outer diameter valve seat is formed by the upper seating surface 160 of the valve seat 132. The example ID valve seat is formed by an outer diameter peripheral surface 164 of an inner valve seat member 166. Member 166 is centrally secured to a valve guide 170, which in turn is mounted atop top plate 92. One or more springs 180 (e.g., a circumferential array of metal coil springs retained in pockets 182 in the guide (e.g., three to twenty such spring and pocket combinations per cylinder, or eight to sixteen spring and pocket combinations, of which an exemplary twelve spring and pocket combination is shown) may bias the valve element 152 to its closed state.

As the piston moves upward toward its top dead center condition, the pressure in the headspace will eventually exceed the pressure in the discharge plenum. At this point (or after this due to the biasing of the discharge valve), the discharge valve element 150 will move from its closed state toward an open state, allowing refrigerant to pass from the headspace into the discharge plenum. When the piston reaches the top dead center, the discharge valve closes again.

In this exemplary configuration of the discharge valve, the piston protrusion 80 includes a central recess 200 (fig. 1A) that receives and accommodates the discharge valve inner seat member 166 as the piston approaches top dead center in order to minimize headspace.

As the piston approaches top dead center, the gas in the small space above the transverse portion 54 of the upper surface 52 will be driven upward. In the baseline system, this refrigerant is driven upward between the lateral surface 82 of the projection 80 and the adjacent ID surface 134 of the valve seat 132. The tightness of the space may cause flow resistance, thereby reducing compressor efficiency. Thus, fig. 1A adds passage 220 to the baseline piston configuration. The channel extends from a lower end 224 to an upper end 226. The lower end may generally form an inlet port (inlet) and the upper end 226 may generally form an outlet port (outlet) for flow therethrough during said final stage of upward piston movement to the top dead center position. The exemplary lower end 224 follows the tab lateral surface 82; however, the exemplary upper end 226 is the following recess 200. Exemplary channels 220 are closed channels (e.g., they have a complete transverse perimeter), as opposed to open channels or grooves. Thus, the example passage 220 may be formed by drilling a hole in a cast piston. Eventually a set of exemplary passages are distributed circumferentially about the piston and cylinder axis 502. The exemplary configuration has four such channels 220 (fig. 3). A broader range is 1 to 10 or 2 to 8.

During the latter stages of upward movement, the lower end 224 of the passageway will be exposed between above the suction valve element and below the transverse portion 52 of the rising surface of the piston. Further upward movement of the piston will tend to drive some of the gas up through the passage 220, away from the upper end/outlet 226 and out of the discharge valve. Prototype testing has shown a substantially 1% efficiency improvement at rated conditions for the baseline compressor. Depending on the implementation, embodiments may be configured to provide slightly increased capacity (or potentially slightly decreased capacity).

Exemplary dimensions for each hole relate to a diameter of 0.5 mm and 4.9 mm²Cross-sectional area. An exemplary total cross-sectional area of the passage (e.g., four times the bore cross-sectional area of an exemplary piston) is 19.6 mm²。

The holes bring about a 5% increase in TDC clearance volume when compared to other similar baseline compressors lacking the holes/passages 220. This may generally reduce overall performance. However, since the effect of the improved flow is greater than the effect of the increased clearance volume, an increase in performance and a decrease in power is observed. Thus, it is expected that the flow benefit of pore size in exchange for the return of shrinkage will be offset by the increased clearance volume and, if the pores are too large, will result in reduced performance. There may also be a lower threshold for the pore size where small dimensions do not provide an overall benefit due to the flow resistance through the pores.

The cross-sectional area of the replaceable individual holes is at least 2.0 mm²Or 2.0 mm²To 10.0 mm². Alternatively the total cross-sectional area is at least 5.0 mm²Or 5.0 mm²To 50.0 mm²。

Other modifications made with respect to the baseline compressor are the addition of a vent 300 (fig. 1B) to the spring pocket 182. In one exemplary variation, the base wire spring pocket is a blind hole that extends upwardly from the lower peripheral surface portion 302 of the valve guide 170. The upper end of the baseline spring 180 seats against the base of the blind hole. The exemplary modification adds the vent 300 as a narrower passageway, such as a coaxial bore of smaller diameter, leaving a shoulder 304 formed by a peripheral portion of the bottom surface of the baseline sleeve seat. Vent 300 thus has a lower end 310 at hub 182 and an upper end 312 at an upper surface 314 of valve guide 170.

One or more of several advantages may be obtained by adding the vent 300. The responsiveness of the bleed valve may be improved by allowing the sleeve seat 182 to vent. For example, when the valve element 150 is driven upward from its closed position, vapor above the valve element is driven into the socket or is forced laterally out through the circumferential opening 320. To the extent that vapor is driven into the socket, this may cause a back pressure in the socket that resists the upward movement of the valve element 150. This may also involve back pressure in the sense that the vapor is driven laterally outward, and may cause the vapor to compete with the vapor exhausted from the cylinder.

One or both of these situations can be addressed by adding vents. In some embodiments, the vent may allow vapor initially above the valve element 150 to vent into the hub and allow vapor in the hub to vent outward.

Other potential advantages of some embodiments relate to the transfer of flow from the cylinder through the sleeve seat and the vent. For example, the nature of the spring bias may be such that the valve element 150 does not plateau and closes the lower end of the sleeve seat 182 during some or all of the discharge stroke of the piston. In this case, a portion of the vapor vented from the cylinder may pass radially and axially around the OD perimeter 160 of the valve element 150 and then back inward and upward through the sleeve seat 182 and vent 300. In other cases, a channel or other passageway may be provided such that flow from the cylinder can pass through the sleeve seat and the vent even if the valve element is flat-topped against the stop surface.

Independent of the modifications discussed above with respect to the piston channel 220, prototype testing showed a capacity increase of approximately 2% and an EER improvement of 1% at rated conditions.

Various other modifications may be made to the passageway 220 or the vent 300. In one example, the illustrated channel 220 may be replaced with a fully open channel along the circumference of the protrusion or some hybrid of open and closed channels, such as converting an open channel along a lower portion of the circumference of the protrusion into a closed channel that penetrates into the recess 200. Another variation may involve replacing the array of coil springs 180 and sockets 182 with a single wave spring (e.g., in an annular space, such as a downwardly opening channel). The vent may extend upwardly from the annular space.

Compressors are used in vapor compression systems (e.g., refrigeration systems including chillers, air conditioners, heat pumps, etc.). In such systems, the compressor may drive a flow of refrigerant along a recirculation flow path through one or more heat rejection heat exchangers and one or more heat absorption heat exchangers. The basic configuration involves a sequential flow path through the heat rejection heat exchanger, the expansion device, the heat absorption heat exchanger, and back to the compressor.

The compressor may be manufactured using other conventional or yet to be developed materials and techniques.

The use of "first," "second," and the like in the description and in the claims is for distinguishing between similar elements and not necessarily for indicating a relative or absolute importance or temporal order. Similarly, the identification of an element in one claim as "first" (or the like) does not preclude the identification of such "first" element as "second" (or the like) in another claim or in the specification.

One or more embodiments have been described. Nevertheless, it will be understood that various modifications may be made. For example, when applied to an existing basic system, the details of such configuration or its associated use may influence the details of the particular implementation. Accordingly, other embodiments are within the scope of the following claims.

Claims

1. A compressor (20) comprising:

a housing (22); and

at least one piston (40) mounted for reciprocating movement, each piston in a respective cylinder (42) of the housing, the at least one piston having a circumferential surface (50) and an upper surface (52); and

at least one discharge valve, the at least one discharge valve comprising:

an annular valve element (150) movable between a closed state and an open state;

a valve guide (170);

one or more springs (180) at least partially retained by the valve guide to bias the valve element from the open state toward the closed state; and

one or more vents (300) in the valve guide providing a flow path from an area above the valve element up through the valve guide,

wherein: the one or more springs are partially housed in one or more pockets (182); and the one or more vents extend to the one or more sockets,

wherein: one or more circumferential openings (320) provide communication from the cylinder to a discharge plenum (76),

and wherein: the vent extends to a base of the nest against which an end of the one or more springs is seated.

2. The compressor of claim 1, wherein:

the plurality of springs are a plurality of coil springs.

3. A compressor according to any one of the preceding claims, wherein:

the plurality of springs is eight to sixteen springs per cylinder.

4. The compressor of claim 1, wherein:

each of the one or more vents is coaxial with a respective associated one of the one or more sockets.

5. The compressor of claim 1, further comprising:

a motor (28);

a crankshaft (34) driven by the motor; and

at least one connecting rod (48) coupling the crankshaft to the at least one piston.

6. The compressor of claim 1, wherein:

the one or more vents each comprise a bore.

7. The compressor of claim 1, wherein:

the at least one piston comprises a plurality of identical pistons.

8. The compressor of claim 1, wherein:

the cylinder is formed in a cylinder block (44);

a valve plate assembly (70) mounted to the cylinder block; and is

The valve guide is mounted to the valve plate assembly.

9. The compressor of claim 8, wherein:

the valve plate assembly having a valve seat (132) forming a seating surface (130) of the suction valve;

the piston upper surface having an outer portion (54) and a projection (80) extending centrally upwardly; and is

The piston has a top dead center condition wherein the protrusion is partially received within the valve seat.

10. The compressor of claim 9, wherein:

the valve seat forming an outer seating surface (160) of the discharge valve;

the valve plate assembly having an inner valve seat (166) forming an inner seating surface (164) of the discharge valve;

the piston has a recess (200) in the protrusion; and is

In the top dead center condition, the inner valve seat is partially received within the recess.

11. A method for manufacturing a compressor according to any one of the preceding claims, the method comprising:

drilling to form at least one of the vents.

12. A method for using the compressor of any one of claims 1 to 10, the method comprising:

reciprocating the piston in the cylinder, a fluid flow passing through at least one of the vents during an upward portion of the reciprocating motion.

13. The method of claim 12, wherein:

the fluid flow is a branch of the flow exiting the cylinder, while the other branch exits from a circumferential opening.

14. A vapour compression system comprising a compressor as claimed in any one of claims 1 to 10.

15. The vapor compression system of claim 14, which is a refrigeration system.