HK1117211B - A compressor apparatus and method for remanufacturing a compressor or reengineering a configuration of the compressor - Google Patents

Description

Compressor installation and method for remanufacturing a compressor or reengineering a configuration of the compressor

Technical Field

The present invention relates to a compressor. More particularly, the present invention relates to refrigerant compressors.

Background

Screw-type compressors are commonly used in air conditioning and refrigeration applications. In such compressors, intermeshed male and female lobed rotors or threads are rotated about their axes to pump the working fluid (refrigerant) from a low pressure inlet end to a high pressure outlet end. During rotation, successive lobes of the male rotor act as pistons driving refrigerant downstream and compressing it within the space between a pair of adjacent female rotor lobes and the housing. Likewise, successive lobes of the female rotor produce compression of refrigerant in the space between a pair of adjacent male rotor lobes and the housing. The interlobe spaces of the male and female rotors in which compression occurs form compression pockets (alternatively described as male and female portions that share a compression pocket joined at a mesh zone). In one implementation, the male rotor is coaxial with the electric drive motor and is supported by bearings at the inlet and outlet sides of its impeller working portion. There may be multiple female rotors engaged with a particular male rotor or vice versa.

When one of the interlobe spaces is exposed to the inlet port, the refrigerant enters the space essentially at suction pressure. As the rotor continues to rotate, at some point during rotation, the space is no longer in communication with the inlet port and the flow of refrigerant to the space is cut off. After closing the inlet port, the refrigerant is compressed as the rotor continues to rotate. At some point during rotation, each space intersects the associated outlet port and the closed compression process is terminated. The inlet and outlet ports may each be radial, axial, or a hybrid combination of axial and radial ports.

When full capacity operation is not required, it is often desirable to temporarily reduce the refrigerant mass flow through the compressor (with or without a reduction in the compressor volume index) by delaying the closing of the inlet port. Such unloading is often provided by a slide valve having a valve element with one or more portions whose positions (when the valve is translated) control the respective suction-side closing and discharge-side opening of the compression pockets. The primary effect of the slide valve unloading movement is to reduce the initial trapped suction volume (and hence compressor capacity); a reduction in the volume index is a typical side effect. Exemplary slide valves are disclosed in U.S. patent application publication No.20040109782A1 and U.S. patent nos.4,249,866 and 6,302,668.

Disclosure of Invention

According to one aspect of the invention, a compressor apparatus comprises: a housing having a first port and a second port along a flow path; one or more working elements cooperating with the housing to define a compression passage along the flow path between a suction position and a discharge position; the slide valve is unloaded. The valve is provided with a valve element having a range between a first state and a second state, the second state being unloaded relative to the first state. During movement between the first and second states, the first surface of the valve element is in sliding engagement with the second surface of the housing. The compressor includes a mechanism for lubricating the first surface and the second surface. The range is a range of linear translation, the second surface being within the rotor case. The mechanism has at least one of the following features: at least partially formed on a support extending from a downstream face of the rotor case into a discharge plenum (plenum); and a passageway formed at least partially through the rotor case of the housing, the passageway being generally upward from a port located within the oil accumulation in the discharge plenum.

In various implementations, the mechanism may include a passage through or along the support member for the valve element to extend into the discharge plenum. The mechanism may include a passage through or along the housing. The mechanism may be provided in remanufacturing a compressor or reengineering a compressor configuration from an initial baseline configuration.

According to another aspect of the invention, a method for remanufacturing a compressor or reengineering a configuration of the compressor includes providing an initial such compressor or configuration having: a housing; one or more working elements cooperating with the housing to define a compression path between a suction position and a discharge position; and an unloader slide valve having a valve element with a range between a first state and a second state, the second state being unloaded relative to the first state, a first surface of the valve element being in sliding engagement with a second surface of the housing during movement between the first and second states. The method also includes adjusting the compressor or configuration to include a mechanism for lubricating the first and second surfaces, the adjusting including modifying a bearing extending into the discharge plenum.

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

Drawings

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

Fig. 2 is a transverse cross-sectional view of the compressor discharge plenum of fig. 1 along line 2-2 showing the slide valve support.

Fig. 3 is a cross-sectional view of the slide valve assembly of fig. 2 in a fully loaded state, the discharge plenum being along line 3-3.

Fig. 4 is a view of the slide valve of fig. 3 in a relatively unloaded state.

Fig. 5 is a view of a first alternative spool valve support.

Fig. 6 is a view of a second alternative slide valve support.

FIG. 7 is a partial schematic view of a third alternative slide valve support assembled.

Fig. 8 is a view of the alternative slide valve support of fig. 7.

FIG. 9 is a partial schematic view of a fourth alternative slide valve support assembled.

Fig. 10 is a partial schematic view of slide valve lubrication passages in the rotor housing.

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

Detailed Description

FIG. 1 shows a compressor 20 having a housing assembly 22, the housing assembly 22 containing a motor 24 driving rotors 26 and 28, the rotors 26 and 28 having respective longitudinal axes 500 and 502. In the exemplary embodiment, rotor 26 has a male impeller body or working portion 30 that extends between a first end 31 and a second end 32. The working portion 30 meshes with a female impeller body or working portion 34 of the female rotor 28. The working portion 34 has a first end 35 and a second end 36. Each rotor includes shaft portions (e.g., stubs 39, 40, 41, and 42 formed integrally with the associated working portion) extending from the first and second ends of the associated working portion. Each of the shaft stubs is mounted to the housing by one or more bearing assemblies 44 for rotation about the associated rotor axis.

In an exemplary embodiment, the motor is an electric motor having a rotor and a stator. One of the shaft stubs of one of the rotors 26 and 28 may be coupled to the motor's rotor to permit the motor to drive that rotor about its shaft center. When so driven in a first direction of operation about the shaft center, the rotors drive the other rotor in a second, opposite direction. The exemplary housing assembly 22 includes a rotor housing 48 having an upstream/inlet end face 49 approximately midway along the motor length and a downstream/discharge end face 50 substantially coplanar with the rotor body ends 32 and 36. Many other configurations are possible.

The exemplary housing assembly 22 further includes a motor/inlet housing 52, the motor/inlet housing 52 having a compressor inlet/suction port 53 at an upstream end and having a downstream face 54 mounted to the rotor housing downstream face (e.g., mounted with bolts through both housing pieces). The assembly 22 further includes an outlet/discharge housing 56, the outlet/discharge housing 56 having an upstream face 57 mounted to the rotor housing downstream face and having an outlet/discharge port 58. The exemplary rotor housing, motor/inlet housing, and outlet housing 56 may each be formed as castings subject to further finishing.

Surfaces of the housing assembly 22 combine with the enmeshed rotor bodies 30 and 34 to define inlet and outlet ports to compression pockets compressing and driving a refrigerant fluid 504 from a suction (inlet) plenum 60 to a discharge (outlet) plenum 62 (fig. 2). A number of pairs of male and female compression pockets are formed by the housing assembly 22, the male rotor body 30 and the female rotor body 34. Each compression pocket is bounded by the outer surfaces of the enmeshed rotors, portions of the cylindrical surfaces of the bore walls of the male and female rotors in the rotor case and its continuation along the slide valve, and portions of the face 57.

Fig. 2 shows further details of an exemplary flow path at the outlet/discharge port 58. A check valve 70 is provided having a valve element 72 mounted within a protruding portion 74 of the outlet housing 56. The exemplary valve element 72 is a front-sealing poppet valve having a stem/shaft 76 integrally formed with a head 78 and extending downstream from the head 78 along a valve axis 520. The head has a back/underside surface 80 that engages an upstream end of a compression biasing spring 82 (e.g., a metal coil). The downstream end of the spring engages an upstream facing shoulder 84 of a sleeve/guide 86. The bushing/guide 86 may be integrally formed with or mounted relative to the housing and has a central bore 88 slidingly receiving the rod for reciprocal movement between an open condition (not shown) and the closed condition of fig. 2. The spring 82 biases the element 72 upstream toward the closed condition. In the closed condition, the annular peripheral seating portion 90 of the head upstream surface abuts the annular seat 92 at the downstream end of the port 94 from the discharge plenum.

For capacity control/unloading, the compressor has a slide valve 100 provided with a valve element 102. The valve element 102 has a portion 104 along the mesh zone between the rotors (i.e., along the high pressure cusp (cusp)). The exemplary valve element has a first portion 106 (fig. 3) at the discharge plenum and a second portion 108 at the suction plenum. The valve element is movable to control compressor capacity to provide unloading. The exemplary valve moves by linear translation parallel to the rotor axis.

Fig. 3 shows the most upstream position of the valve element in its range of motion. In this position, the compression pockets are relatively closed upstream and the capacity is a relative maximum (e.g., at least 90% of the maximum displacement volume for the rotor, and often about 99%). Fig. 4 shows the valve element moved to the most downstream position. In this unloaded state, the capacity is reduced (e.g., to a displacement volume of less than 40% of the fig. 3 displacement volume or maximum displacement volume, and often less than 30%). In an exemplary spool valve, movement between two positions is driven by a combination of spring force and fluid pressure. The main spring 120 biases the valve element from the loaded state to the unloaded state. In the exemplary valve, the spring 120 is a metal coil spring that surrounds a shaft 122 that couples the valve element to a piston 124. The piston is mounted within a bore (interior) 126 of a cylinder 128 formed within a sliding housing member 130 attached to the outlet housing. The shaft passes through a bore 132 in the outlet housing. The spring is compressed between the underside 134 of the piston and the outlet housing. A proximal portion 136 of the cylinder interior is in pressure-balanced fluid communication with the discharge plenum through a gap between the bore and the shaft. The headspace 138 is coupled to one of the following by electronically controlled solenoid valves 140 and 142 (shown schematically): a high pressure fluid source 144 at or near discharge (e.g., coupled to an oil separator); and a low pressure drain/reservoir 150 that may be at or near suction (e.g., return). A port 146 is shown schematically in the head space within the cylinder and at the end of the piping network connecting valves 140 and 142. In an exemplary implementation, portions of the network of pipes may be formed within the casting of the housing component.

The loaded position/state of fig. 3 can be achieved by coupling headspace 138 to source 144 and isolating it from drain/reservoir 150 by appropriate control of valves 140 and 142. The unloaded position/condition of fig. 4 can be achieved by coupling headspace 138 to drain/reservoir 150 and isolating it from source 144 by appropriate control of valves 140 and 142. An intermediate (partially loaded) state (not shown) may be achieved by alternately connecting headspace 138 to source 144 or drain/reservoir 150 using an appropriately selected time span for connection to each, perhaps in combination with: the headspace 138 is isolated from the source 144 and the drain/reservoir 150 at a suitably selected time span (e.g., by a suitable modulation technique).

Returning to fig. 2, the interfitting of the slide valve element 102 and the rotor housing is seen. The spool valve element 102 has a single convex circular cylindrical outer surface portion 200. This is closely received within the rotor housing bore defined by the circular cylindrical inner surface portion 202 extending from the rotor housing end surface 50. There is a linear sliding interaction between surfaces 200 and 202 during loading and unloading. Fig. 2 further shows concave circular cylindrical outer surface portions 206 and 208 of member 102 in close proximity to the lobes of rotors 26 and 28, respectively. Sliding interaction between surfaces 200 and 202 may potentially damage one or both of surfaces 200 and 202. Accordingly, it may be desirable to provide additional support for the valve element 102 and to provide lubrication.

To provide additional support for the valve element 102, a shelf-like support 220 (fig. 2) is provided within the discharge plenum 62. The exemplary support 220 includes a mounting flange 222 that is secured against the rotor housing discharge end surface 50. Extending from the opposite surface of flange 222 is a sleeve portion 224 integrally formed therewith. The sleeve 224 has an upper/inner side surface 225 that is locally aligned with the surface 202 to conjointly engage the surface 200. The sleeve has first and second longitudinal edges 226 and 228 and a distal end or rim 230. An exemplary annular span along surface 200 between edges 226 and 228 is 90 to 180 °, more narrowly 120 to 160 °.

The bearing 220 may further include features for facilitating lubrication of the sliding interaction between the surface 200 on the one hand and the surfaces 202 and 225 on the other hand. One feature includes the inclination of edges 226 and 228 toward element 102. As refrigerant fluid 540 exits the compression pockets and passes through surfaces 206 and 208, entrained oil may land on edge surfaces 226 and 228. The inclination directs the oil between surfaces 200 and 225. As the valve reciprocates during the load and unload cycles, some of the oil is further transferred upstream and downstream to lubricate the interaction between surfaces 200 and 202. An exemplary tilt is at least 5 (shown as approximately 10). Additional volumes of oil accumulation on surfaces 226 and 228 may be achieved by more gradual tilting (e.g., to 30 to 45). Alternatively, additional volume of oil accumulation may be achieved using multi-faceted surfaces, with at least the surfaces closest to the valve 102 having a greater slope (e.g., such surfaces 340 and 342 in fig. 5 discussed below).

Further lubrication features may be incorporated into the bearing 220. These features may supplement or replace leakage/weepage fluid from the edges into the fine clearance between the spool valve surface 200 and the bearing surface 225. These features may more fully direct the lubrication fluid. Fig. 5 shows an alternative support 320 having a flange 322 and a sleeve portion 324. There is a chamfer 330 at the junction between the concave cylindrical portion of the inboard/upper surface 326 and the upstream face 328 of the flange 322. A small amount of oil may be trapped in this ramp (e.g., a 15 ° ramp 4mm long) to maintain lubrication. Oil that is initially collected on one or both edges will flow down the sides of the channel (formed by the chamfer and adjacent rotor housing face) to accumulate in the bottom and lubricating surface 200 (and surfaces 202 and 326 therefrom).

Fig. 5 further shows an annular channel 332 in surface 326 that is slightly recessed from the distal end 334 of the sleeve portion. The channel 332 joins the edges 336 and 338 to partially receive oil collected by the edges. The exemplary edges are double-sided, each having a laterally outboard portion 340 at a lesser slope (e.g., 10 °) and a more sloped portion 342 inboard thereof (e.g., 30 ° angle).

Fig. 6 shows yet another alternative support 420 having a flange 422 and a sleeve portion 424. The sleeve 424 has an inner/upper surface 426. A chamfer 430 is formed at the junction with the flange upstream surface 428. A relieved area 442 extends along each of edges 436 and 438 and the inner side of face 440. However, the initial removed area does not reach the distal end 434, but terminates just before it. The relieved area also extends through the flange 422 to communicate with the bevel. Thus, in operation, relieved region 442 due to unrelieved distal portion 444 can trap a substantial accumulation of oil against the valve element. The oil may then be directed to the chamfer 430 to provide a larger annular footprint.

Fig. 7 shows an alternative support 460 in which the flange 464 is partially immersed in an oil accumulation 466 in the discharge plenum. One or more channels 468 extend from one or more inlets 469 low on the periphery of the flange (e.g., one channel on each side). The passage extends through the flange and into the rotor housing 48 to an outlet port 470 in the bore wall 202. Exemplary port 470 is proximate the junction of spool valve element surface 200 with surface 206 on one side and surface 208 on the other side of surface 206. The closer physical proximity of the port 470 to the suction condition helps to cause a pressure-induced flow 560 of oil to lubricate the surfaces 200 and 202. Fig. 8 shows intermediate ports 472 at the upstream face of the flange that align with associated intermediate ports (not numbered) on the rotor case end face 50.

Fig. 9 shows an alternative support 480 in which, for ease of machining, the passages 481 are formed by open channels 482 in the flange suction side (closed by face 50) in combination with open channels 484 in the rotor box bore extending along the bottom end of face 202. The passage has an inlet 486 and an outlet 488.

Fig. 10 shows an alternative embodiment in which a channel 490 extends solely through the rotor housing from an inlet port 491 in surface 50 below the surface of the accumulation 466 and to an outlet port 492 in surface 202. For this structure, a support (not shown) is optional.

One or more embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, in a rebuild or remanufacture situation, details of the existing compressor configuration may particularly influence or dictate details of the implementation. Accordingly, other embodiments are within the scope of the following claims.

Claims (12)

1. A compressor apparatus (20) comprising:

a housing (22) having a first port (53) and a second port (58) along a flow path;

one or more working elements (26, 28) cooperating with the housing to define a compression passage along the flow path between a suction position (60) and a discharge position (62);

an unloader slide valve (100) provided with a valve element (102) having a range between a first state and a second state, the second state being unloaded relative to the first state, a first surface (200) of the valve element (102) being in sliding engagement with a second surface (202) of the housing (22) during movement between the first and second states; and

means for lubricating the first surface (200) and the second surface (202);

wherein the content of the first and second substances,

the range is a linearly translated range;

the second surface (202) is within the rotor case (48); and

the mechanism has at least one of the following features:

at least partially formed on a support (220, 320, 420, 460, 480) extending from a downstream face (50) of the rotor case (48) into a discharge plenum (62); and

a passage (468, 481, 490) formed at least partially through a rotor case (48) of the housing (22) generally upward from a port (469, 486, 491) positioned within oil accumulation in the discharge plenum (62).

2. The apparatus of claim 1 wherein the mechanism comprises a beveled edge (226, 228; 336, 338; 436, 438) of a sleeve portion of the support extending from a mounting flange of the support.

3. The apparatus of claim 2, wherein:

said sleeve portion having a generally concave cylindrical upper surface (225, 326, 426) extending into said mounting flange; and

the mechanism includes a ramp at the junction of the upper surface and the upstream face of the mounting flange.

4. The apparatus of claim 3, wherein:

the mechanism includes an at least partially annular channel in the upper surface.

5. The apparatus of claim 1, wherein:

the mechanism includes a longitudinal channel formed along an edge of the support and cooperating with the valve element to trap oil.

6. The apparatus of claim 1, wherein the one or more working elements comprise:

a male impeller rotor (26) having a first axis of rotation (500); and

a female lobed rotor (28) having a second axis of rotation (502) and meshing with the male lobed rotor.

7. The apparatus of claim 6, wherein:

in the first state, the compressor is at least 90% of maximum displacement volume; and

in the second state, the compressor is less than 40% of the displaced volume of the first state.

8. The apparatus of claim 1, wherein:

the mechanism includes the passage extending from a discharge end face (50) of a rotor case (48) of the housing (22).

9. A method for remanufacturing a compressor (20) or reengineering a configuration of the compressor comprising:

providing an initial such compressor or configuration having:

a housing (22);

one or more working elements (26, 28) cooperating with the housing to define a compression path between a suction position (60) and a discharge position (62); and

an unloader slide valve (100) provided with a valve element (102) having a range between a first state and a second state, the second state being unloaded relative to the first state, a first surface (200) of the valve element (102) being in sliding engagement with a second surface (202) of the housing (22) during movement between the first and second states; and

adjusting such compressor or configuration to include a mechanism for lubricating the first and second surfaces (200, 202) includes modifying a bearing (220, 320, 420, 460, 480) extending into a discharge plenum (62).

10. The method of claim 9, wherein the modifying comprises adding a channel on an upper surface of the support.

11. The method of claim 10, wherein the adding comprises adding a passageway (490) through a rotor case (48) of the housing (22).

12. The method of claim 10, wherein the adding comprises adding a passage (468, 481, 490) at least partially through a rotor case (48) of the housing (22) generally upward from a port (469, 486, 491) positioned within an oil accumulation in the discharge plenum (62).