EP3252310B1 - Screw compressor - Google Patents
Screw compressor Download PDFInfo
- Publication number
- EP3252310B1 EP3252310B1 EP15879918.9A EP15879918A EP3252310B1 EP 3252310 B1 EP3252310 B1 EP 3252310B1 EP 15879918 A EP15879918 A EP 15879918A EP 3252310 B1 EP3252310 B1 EP 3252310B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- oil
- slide valve
- back surface
- gap
- screw compressor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000005192 partition Methods 0.000 claims description 42
- 238000002347 injection Methods 0.000 claims description 16
- 239000007924 injection Substances 0.000 claims description 16
- 239000003921 oil Substances 0.000 description 154
- 238000007789 sealing Methods 0.000 description 32
- 239000003507 refrigerant Substances 0.000 description 26
- 238000007906 compression Methods 0.000 description 17
- 230000006835 compression Effects 0.000 description 16
- 238000010586 diagram Methods 0.000 description 16
- 230000000694 effects Effects 0.000 description 5
- 230000000593 degrading effect Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000005057 refrigeration Methods 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000010721 machine oil Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
- F04C18/48—Rotary-piston pumps with non-parallel axes of movement of co-operating members
- F04C18/50—Rotary-piston pumps with non-parallel axes of movement of co-operating members the axes being arranged at an angle of 90 degrees
- F04C18/52—Rotary-piston pumps with non-parallel axes of movement of co-operating members the axes being arranged at an angle of 90 degrees of intermeshing engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
- F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
- F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
- F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
- F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C27/00—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids
- F04C27/008—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids for other than working fluid, i.e. the sealing arrangements are not between working chambers of the machine
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
- F04C28/10—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by changing the positions of the inlet or outlet openings with respect to the working chamber
- F04C28/12—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by changing the positions of the inlet or outlet openings with respect to the working chamber using sliding valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
- F04C29/0007—Injection of a fluid in the working chamber for sealing, cooling and lubricating
Definitions
- the present invention relates to a screw compressor, and particularly to a screw compressor including a slide valve.
- Conventional screw compressors each include a casing body and a screw rotor rotatably hounded in a cylinder chamber formed inside the casing body.
- a screw compressor further includes a slide valve that controls the operation capacity by allowing a part of refrigerant introduced into a compression chamber to be bypassed to a low-pressure space during a compression process (see Patent Literature 1, for example).
- the slide valve is disposed on an outer circumference of the screw rotor, and is movable in the axial direction of the screw rotor.
- the slide valve is provided on the outer circumference of the screw rotor to be movable in the axial direction of the screw rotor, and a gap opens up between a casing body side (hereinafter referred to as the back surface side) of the slide valve and a slide valve side of the casing body.
- a screw rotor-side surface (hereinafter referred to as the inner circumferential surface) of the slide valve is normally disposed to be located outside in the radial direction of an inner circumferential surface of the cylinder chamber to prevent mutual contact between the slide valve and the screw rotor. Consequently, the gap between the inner circumferential surface of the slide valve and the outer circumferential surface of the screw rotor is greater than the gap between an inner circumferential surface of the cylinder and the outer circumferential surface of the screw rotor.
- the back surface side and the inner circumferential surface side of the slide valve each have a structurally necessary gap, as described above. Through these gaps, more than a small amount of refrigerant inevitably leaks from a discharge pressure (high pressure) side to a suction pressure (low pressure) side, degrading performance.
- a technique of eliminating or reducing the refrigerant leakage from the inner circumferential surface of the slide valve includes a covering member provided to the inner circumferential surface of the slide valve to fill the gap between the inner circumferential surface of the slide valve and the outer circumferential surface of the screw rotor (see Patent Literature 2, for example).
- US3314597A relates to a screw compressor which comprises a casing provided with a Working space comprising two intersecting cylindrical 'bores with parallel axes located between a low pressure and a high pressure end wall enclosing two cooperating rotors provided with helical lands and intervening grooves having a wrap angle of less than 360, which rotors are sealingly surrounded by said bores.
- DE102011051730A1 discloses a screw compressor housing having screw rotor bores, screw rotors, a drive for the screw rotors, and a slider in a slider receptacle for adjusting a volume ratio of the screw compressor and which extends in a direction towards the high-pressure outlet in a guide trough of the slider receptacle that is open towards the screw rotor bores and which is capable of being positioned in a first position and a second position, wherein the volume ratio of the screw compressor is greater in one of the positions than in the other of the positions, the slider connected to a first cylinder element and cooperates with a second cylinder element, the cylinder elements being at least partially arranged in the insertion space and arranged following the slider in the displacement direction thereof on a side of the slider that is opposite the high-pressure outlet.
- Patent Literature 2 With the covering member provided to the inner circumferential surface of the slide valve, the technique of Patent Literature 2 described above eliminates or reduces the gap between the inner circumferential surface of the slide valve and the outer circumferential surface of the screw rotor, thereby eliminating or reducing the refrigerant leakage from the inner circumferential surface side of the slide valve, as described above.
- the technique of Patent Literature 2 does not eliminate or reduce the refrigerant leakage from the gap on the back surface side of the slide valve.
- the casing body is formed with a partition wall that separates the discharge pressure (high pressure) side and the suction pressure (low pressure) side from each other (hereinafter referred to as the high-low pressure partition wall), and an inner circumferential side of the high-low pressure partition wall faces the back surface side of the slide valve. Further, a gap is opened up between the back surface of the slide valve and an inner circumferential surface of the high-low pressure partition wall to prevent mutual contact with each other. From this gap, the refrigerant leaks owing to the pressure difference between the discharge pressure (high pressure) and the suction pressure (low pressure) at a boundary of the high-low pressure partition wall. The pressure difference tends to be increased particularly in high-pressure refrigerant, such as R410A, substantially degrading performance due to the refrigerant leakage from the back surface side of the slide valve.
- high-pressure partition wall that separates the discharge pressure (high pressure) side and the suction pressure (low pressure) side from each other
- the present invention has been made to solve the above-described problems, and aims to provide a highly efficient screw compressor that eliminates or reduces the refrigerant leakage from the gap between the back surface of the slide valve and the inner circumferential surface of the high-low pressure partition wall.
- a screw compressor according to the invention is defined by the independent claim of the application.
- a screw compressor according to an embodiment of the present invention includes a casing body, a screw rotor disposed to rotate inside the casing body, a slide valve movably provided between the casing body and the screw rotor, a partition wall provided to face a back surface side of the slide valve and configured to divide an interior of the casing body into a discharge pressure space and a suction pressure space, and an injection mechanism configured to supply oil to a gap between an inner circumferential surface of the partition wall and the back surface side of the slide valve to seal the gap.
- An embodiment of the present invention eliminates or reduces the refrigerant leakage from the gap between the back surface of the slide valve and the inner circumferential surface of the high-low pressure partition wall, and improves the performance of the screw compressor.
- Embodiments 2, 4 and 5 are not according to the invention and are present for illustration purposes only.
- Embodiment 3 is according to the invention, while embodiment 1 does not comprise a first oil groove of the invention, and thus it does not fall within the scope of the claims but it is useful for understanding the invention.
- Fig. 1 is a schematic configuration diagram of a refrigeration apparatus including a screw compressor according to Embodiment 1 of the present disclosure.
- the refrigeration apparatus includes devices such as a screw compressor 1, a condenser 5, an expansion valve 6, and an evaporator 7.
- the screw compressor 1 includes a compression unit 2, a motor 3 connected in series with the compression unit 2 to drive the compression unit 2, and an oil separator 4.
- refrigerating machine oil hereinafter referred to as the oil
- the oil separator 4 separates the refrigerant and the oil from each other.
- the separated oil is returned to the compression unit 2 by the pressure difference.
- Fig. 1 illustrates the specifications of the screw compressor 1 including the oil separator 4 inside the screw compressor 1, the oil separator 4 may be configured to be disposed separately outside the screw compressor 1.
- Fig. 2 is a schematic configuration diagram of the screw compressor according to Embodiment 1 of the present disclosure.
- the screw compressor includes a tubular casing body 8, a screw rotor 9 housed inside the casing body 8, and the motor 3 that drives the screw rotor 9 to rotate.
- the motor 3 is formed of a stator 3a inscribed in and fixed to the casing body 8 and a motor rotor 3b disposed inside the stator 3a.
- the screw rotor 9 and the motor rotor 3b are both disposed on the same axis and fixed to a screw shaft 10.
- the screw rotor 9 has an outer circumferential surface formed with a plurality of helical grooves (screw grooves) 11a, and is coupled to and driven to rotate by the motor rotor 3b fixed to the screw shaft 10. Further, the space inside the screw grooves 11a is surrounded by an inner tubular surface of the casing body 8 and a pair of gate rotors (not illustrated) that are in meshing engagement with the screw grooves 11a, thereby forming a compression chamber 11. Further, the interior of the casing body 8 is divided into a discharge pressure side and a suction pressure side by a high-low pressure partition wall 17. The high-low pressure partition wall 17 is provided to the casing body 8 to face a casing body 8 side of a later-described slide valve 14. Further, the discharge pressure side of the casing body 8 is formed with a pair of discharge ports 13, which open to a discharge chamber 12.
- the casing body 8 includes the slide valve 14.
- the slide valve 14 is connected to a rod 15 of a driving device 16, and is movable in the axial direction of the screw rotor 9.
- the slide valve 14, which forms a part of the discharge ports 13, is a mechanism that changes a discharge start (compression completion) position of high-pressure gas compressed in the compression chamber 11, thereby changing a discharge opening time and changing an internal volume ratio.
- the internal volume ratio refers to the ratio between the volume of the compression chamber 11 at suction completion (compression start) time and the volume of the compression chamber 11 immediately before discharge.
- two or more slide valves 14 may be provided, the illustration of the slide valves 14 other than one is omitted.
- the casing body 8 side and a screw rotor 9 side of the slide valve 14 will be referred to as the "back surface side” and the “inner circumferential side,” respectively.
- Fig. 3 is an illustrative diagram of an operation of the conventional screw compressor illustrated for comparison with an operation of Embodiment 1.
- Fig. 4 is a diagram illustrating a refrigerant leakage passage of a conventional slide valve illustrated for comparison with the slide valve of Embodiment 1, with the slide valve viewed from a back surface side.
- the conventional configuration allows a slide valve 140 provided inside a casing body 80 to move in the axial direction of a screw rotor 90.
- a gap opens up between a back surface 140a of the slide valve 140 and an inner circumferential surface 170a of a high-low pressure partition wall 170, which is a part of the casing body 80.
- the high-low pressure partition wall 170 is located at a position separating a discharge pressure (high pressure) side and a suction pressure (low pressure) side from each other. Consequently, refrigerant leaks from the gap, as indicated by an arrow in Fig. 3 , degrading performance.
- Embodiment 1 on the other hand, has the following configuration.
- Fig. 5 is an illustrative diagram of an operation of the screw compressor according to Embodiment 1 of the present disclosure.
- Fig. 6 is a perspective view illustrating an oil passage of the slide valve of the screw compressor according to Embodiment 1 of the present disclosure, with the slide valve viewed from a back surface side of the slide valve.
- the slide valve 14 of Embodiment 1 includes an injection mechanism 20 that injects the oil to a gap between sealing surfaces S, which define the gap between a back surface side 14f of the slide valve 14 and an inner circumferential surface 17a of the high-low pressure partition wall 17.
- the injection mechanism 20 will be described in detail below.
- Fig. 7 is a perspective view of the slide valve of the screw compressor according to Embodiment 1 of the present disclosure, with the slide valve viewed from an inner surface side of the slide valve.
- Fig. 8 is a plan view of the slide valve of the screw compressor according to Embodiment 1 of the present disclosure, with the slide valve viewed from the back surface side of the slide valve.
- Fig. 9 is a view of the slide valve in Fig. 6 , with the slide valve vertically reversed and viewed in the direction of arrow X (in a direction in which a sump 14m is visible).
- Fig. 10 is a sectional view taken along line A-A in Fig. 9 .
- Fig. 11 is a sectional view taken along line B-B in Fig. 9 .
- arrows indicate oil passages.
- the slide valve 14 includes a valve body 14a, a guide portion 14b, and a connecting portion 14c that connects the valve body 14a and the guide portion 14b.
- a gap communicating with the discharge ports 13 is opened up between the valve body 14a and the guide portion 14b to form a part of the discharge ports 13.
- a discharge port end portion 14d of an inner circumferential side 14e on a side of the discharge ports 13 forms a part of the discharge ports 13, and determines the time of discharging the compressed refrigerant.
- the discharge port end portion 14d is moved in the axial direction of the screw rotor 9 at the same as the slide valve 14 is moved in the axial direction of the screw rotor 9, thereby changing the internal volume ratio.
- the guide portion 14b has a connecting hole 15a, to which the rod 15 is connected, as illustrated in Fig. 2 .
- the slide valve 14 of Embodiment 1 is formed with an oil feed hole 14g passing through the slide valve 14 to inject the high-pressure oil to the screw rotor 9.
- a screw rotor portion oil supply port 14i serving as an oil inflow-side opening is located on the back surface side 14f of the slide valve 14, and a screw rotor portion oil feed port 14h serving as an oil outflow-side opening is located on the inner circumferential side 14e of the slide valve 14.
- the hole shape and the number of the oil feed hole 14g are not limited.
- the slide valve 14 of Embodiment 1 is formed with an oil feed hole 14j to inject the oil to the gap (between the sealing surfaces S) between the high-low pressure partition wall 17 and the back surface side 14f of the slide valve 14.
- a slide valve back surface portion oil supply port 14l serving as an oil inflow-side opening of the oil feed hole 14j is located on the back surface side 14f of the slide valve 14.
- a slide valve back surface portion oil feed port 14k serving as an oil outflow-side opening of the oil feed hole 14j is located in a portion, facing the high-low pressure partition wall 17, of the back surface side 14f of the slide valve 14, that is, within the range of the sealing surfaces S.
- the hole shape and the number of the oil feed hole 14j are not limited.
- the oil feed hole 14j corresponds to a first oil feed hole of the present invention.
- the slide valve 14 is formed with the sump 14m recessed on the back surface side 14f. As illustrated in Fig. 9 , the screw rotor portion oil supply ports 14i and the slide valve back surface portion oil supply port 14l are located in the sump 14m.
- the high-pressure oil is injected to a gap between the inner circumferential side 14e of the slide valve 14 and a portion facing the inner circumferential side 14e and a gap between the back surface side 14f of the slide valve 14 and a portion facing the back surface side 14f to eliminate or reduce the refrigerant leakage from the screw rotor 9 and prevent burning.
- the high-pressure oil in the oil separator 4 is first supplied by the pressure difference to the sump 14m provided in the slide valve 14 via a flow passage (not illustrated) inside the casing body 8. Subsequently, the oil supplied to the sump 14m is caused by the pressure difference to flow into the oil feed hole 14g from the screw rotor portion oil supply port 14i provided inside the sump 14m, and passes through the oil feed hole 14g. Then, the high-pressure oil is injected to the screw rotor 9 from the screw rotor portion oil feed port 14h.
- Embodiment 1 is characterized in that the high-pressure oil is injected to a gap between the sealing surfaces S from the back surface side 14f.
- the above-described oil in the sump 14m distributed by the oil separator 4 is used.
- the high-pressure oil in the sump 14m is caused by the pressure difference to flow into the oil feed hole 14j from the slide valve back surface portion oil supply port 14l provided inside the sump 14m, and passes through the oil feed hole 14j.
- the oil is injected to the gap between the sealing surfaces S from the slide valve back surface portion oil feed port 14k.
- the oil feed hole 14j formed in the slide valve 14 corresponds to a part of the injection mechanism 20 of the present invention.
- Embodiment 1 the screw rotor portion oil supply ports 14i and the slide valve back surface portion oil supply port 14l are set to be located inside the same sump 14m, but are not necessarily required to have this configuration, and may be configured to be located in separate sumps 14m. Further, Embodiment 1 basically aims to reduce the refrigerant leakage on the back surface side of the slide valve 14, and the oil feed hole 14j is also applicable to the slide valve 14 not having the oil feed hole 14g. Further, the thickness of the high-low pressure partition wall 17 may be increased to cause an opening of the oil feed hole 14j to face the high-low pressure partition wall 17 even when the slide valve 14 is moved.
- Embodiment 1 includes the injection mechanism 20 that injects the oil to the gap between the sealing surfaces S to seal the sealing surfaces S, thereby eliminating or reducing the refrigerant leakage from the discharge pressure (high pressure) side to the suction pressure (low pressure) side. Consequently, the efficiency of the screw compressor 1 can be improved to contribute to energy saving.
- the injection mechanism 20 is configured to have the oil feed hole 14j passing through the slide valve 14 to supply the oil flowing from the slide valve back surface portion oil supply port 14l of the oil feed hole 14j to the gap between the sealing surfaces S from the slide valve back surface portion oil feed port 14k, that is, simply configured to have a hole formed through the slide valve 14. Consequently, the injection mechanism 20 can be configured at low cost.
- Embodiment 2 is different from Embodiment 1 only in the area having the oil feed hole for feeding the oil to the gap between the sealing surfaces S.
- Fig. 12 is a schematic diagram illustrating main parts of a screw compressor according to Embodiment 2 of the present disclosure.
- Fig. 13 is a perspective view of a slide valve of the screw compressor according to Embodiment 2 of the present disclosure, with the slide valve viewed from a backside of the slide valve.
- Embodiment 2 differences from Embodiment 1 will be described, and configurations not described in Embodiment 2 are similar to those of Embodiment 1.
- Embodiment 2 the oil feed hole 14j formed in the slide valve 14 in Embodiment 1 is eliminated, and an oil feed hole 17b is formed in the high-low pressure partition wall 17, which forms a part of the casing body 8. Further, a configuration is designed in which the inner circumferential surface 17a of the high-low pressure partition wall 17 has a slide valve back surface portion oil feed port 17c serving as an oil outflow-side opening of the oil feed hole 17b, to inject the high-pressure oil flowing into the oil feed hole 17b to the gap between the sealing surfaces S from the slide valve back surface portion oil feed port 17c.
- the position of an oil inflow-side opening of the oil feed hole 17b is not particularly limited as long as the oil inflow-side opening of the oil feed hole 17b is formed at a position at which the oil inflow-side opening is capable of receiving the oil in the screw compressor 1. Further, the hole shape and the number of the oil feed hole 17b are not limited.
- the oil feed hole 17b corresponds to a second oil feed hole of the present invention.
- the high-pressure oil is injected to the gap between the sealing surfaces S from the slide valve back surface portion oil feed port 17c provided in the inner circumferential surface 17a of the high-low pressure partition wall 17. Consequently, the refrigerant leakage from the discharge pressure (high pressure) side to the suction pressure (low pressure) side in the sealing surfaces S can be eliminated or reduced, and the efficiency of the screw compressor 1 can be improved.
- Embodiment 3 is different from Embodiment 1 only in that an oil groove is provided in the back surface side 14f of the slide valve 14.
- Fig. 14 is a perspective view of a slide valve of a screw compressor according to Embodiment 3 of the present invention.
- Embodiment 3 differences from Embodiment 1 will be described, and configurations not described in Embodiment 3 are similar to those of Embodiment 1.
- the back surface side 14f of the valve body 14a of the slide valve 14 is formed with an oil groove 18 extending in the circumferential direction of the back surface side 14f to efficiently spread the oil injected to the gap between the sealing surfaces S in Embodiment 1 over the sealing surfaces S.
- the position of processing the oil groove 18 is set to correspond within the range of the sealing surfaces S.
- the oil groove 18 corresponds to a first oil groove of the present invention.
- the sectional shape and the number of the above-described oil groove 18 are not limited.
- Fig. 15 is an illustrative diagram of the positional relationship between the high-low pressure partition wall and the screw grooves corresponding to a stop position of the slide valve of the screw compressor according to Embodiment 3 of the present invention.
- the oil groove 18 may extend across more than one of the screw grooves 11a, depending on a sliding position of the slide valve 14. The pressures in the screw grooves 11a are different from each other.
- the oil groove 18 may allow communication between a high pressure-side screw groove 11a and a low pressure-side screw groove 11a and cause refrigerant leakage from the high-pressure side to the low-pressure side.
- the oil groove 18 is not limited to the configuration in which the oil groove 18 is provided over the entirety in the circumferential direction of the back surface side 14f of the slide valve 14, and an area not processed to form a groove may be left in the back surface side 14f.
- the area having the oil groove 18 is not limited to the back surface side 14f of the slide valve 14, and may be the inner circumferential surface 17a of the high-low pressure partition wall 17 forming a part of the sealing surfaces S, or may be both the back surface side 14f and the inner circumferential surface 17a.
- the oil groove is formed to extend in the circumferential direction of the inner circumferential surface 17a similarly to the oil groove 18.
- the oil groove thus provided in the inner circumferential surface 17a of the high-low pressure partition wall 17 corresponds to a third oil groove of the present invention.
- Embodiment 3 effects similar to those of Embodiment 1 are obtained, and the following effects are obtained. That is, the oil injected to the gap between the sealing surfaces S from the back surface side 14f of the slide valve 14 is more likely to spread over the entire circumference of the back surface of the slide valve through the oil groove 18. With the oil groove 18, Embodiment 3 is more capable of eliminating or reducing the refrigerant leakage from the discharge pressure (high pressure) side to the suction pressure (low pressure) side in the sealing surfaces S than in a case in which the configuration of Embodiment 1 (the configuration having the slide valve back surface portion oil feed port 14k) is implemented alone. Consequently, the efficiency of the screw compressor 1 can be further improved.
- Embodiment 4 corresponds to a configuration combining the configuration of Embodiment 2 and the configuration of Embodiment 3. That is, the oil groove 18 is provided to the slide valve 14 of the screw compressor 1 of Embodiment 2, which is characterized in that the oil is injected to the gap between the sealing surfaces S from the side of the high-low pressure partition wall 17.
- Features such as the shape of the oil groove 18 and the position at which the oil groove 18 is formed are similar to those of Embodiment 3.
- Fig. 16 is a perspective view of a slide valve of a screw compressor according to Embodiment 4 of the present disclosure.
- Embodiment 4 differences from Embodiment 2 will be described, and configurations not described in Embodiment 4 are similar to those of Embodiment 2.
- the oil injected to the gap between the sealing surfaces S from the side of the high-low pressure partition wall 17, as indicated by a solid-white arrow in Fig. 16 flows along the oil groove 18, as indicated by solid arrows, and efficiently spreads over the sealing surfaces S.
- Embodiment 4 effects similar to those of Embodiment 2 are obtained, and the following effects are obtained. That is, the oil injected to the gap between the sealing surfaces S from the side of the high-low pressure partition wall 17 is more likely to spread over the entire circumference of the back surface of the slide valve through the oil groove 18. With the action of the oil groove 18, Embodiment 4 is more capable of eliminating or reducing the refrigerant leakage from the discharge pressure (high pressure) side to the suction pressure (low pressure) side in the sealing surfaces S than in a case in which the configuration of Embodiment 2 (the configuration in which the oil is injected to the gap between the sealing surfaces S from the side of the high-low pressure partition wall 17) is implemented alone. Consequently, the efficiency of the screw compressor 1 can be further improved.
- Embodiment 5 is characterized in allowing communication between the sump 14m and the oil groove 18.
- Fig. 17 is a diagram illustrating a structure of a slide valve of a screw compressor according to Embodiment 5 of the present disclosure.
- the slide valve 14 of Embodiment 1 illustrated in Fig. 9 described above is configured to cause the oil in the sump 14m to pass through the valve body 14a with the oil feed hole 14j to inject the oil to the gap between the sealing surfaces S from the slide valve back surface portion oil feed port 14k.
- Embodiment 5 is configured to cause the oil to flow along the back surface side (the outer circumferential surface) of the slide valve 14 to inject the oil to the gap between the sealing surfaces S.
- the oil feed hole 14j of Embodiment 1 is eliminated, and an oil groove 18a is provided to communicate with the sump 14m to inject the high-pressure oil in the sump 14m to the gap between the sealing surfaces S through the oil groove 18a.
- the oil groove 18a of Embodiment 5 is different from the oil groove 18 of Embodiment 3 only in that the oil groove 18 communicates with the sump 14m, and is similar to the oil groove 18 of Embodiment 3 in the other features.
- the oil groove 18a corresponds to a second oil groove of the present invention.
- the high-pressure oil in the sump 14m can be caused to spread over the sealing surfaces S without the oil feed hole 14j as in Embodiments 1 to 4, which passes through the slide valve 14. Consequently, the refrigerant leakage can be eliminated or reduced and efficiency of the screw compressor 1 can be improved with a simpler configuration.
- Embodiments 1 to 5 may be combined as appropriate.
- Embodiment 1 and Embodiment 2 may be combined to inject the oil to the gap between the sealing surfaces S from both the back surface side 14f of the slide valve 14 and the inner circumferential surface 17a of the high-low pressure partition wall 17.
- Embodiments 1 to 5 are applicable to any screw compressor including a mechanism that has a gap between the back surface side 14f of the slide valve 14 and the inner circumferential surface 17a of the high-low pressure partition wall 17.
- the compressor may be a multi-stage compressor including two or more compression units 2.
- the present invention is useful not only in a screw compressor of constant speed specifications but also in an inverter-driven screw compressor.
- the slide valve 14 capable of changing the internal volume ratio.
- the slide valve to which the present invention is applicable is not limited to the slide valve capable of changing the internal volume ratio.
- the slide valve to which the present invention is applicable may be a volume-control slide valve allowing a part of the refrigerant gas to be bypassed to the suction side (low pressure), or may be an immovable slide valve fixed to the casing body 8.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Applications Or Details Of Rotary Compressors (AREA)
Description
- The present invention relates to a screw compressor, and particularly to a screw compressor including a slide valve.
- Conventional screw compressors each include a casing body and a screw rotor rotatably hounded in a cylinder chamber formed inside the casing body. Also, among the conventional screw compressors, a screw compressor further includes a slide valve that controls the operation capacity by allowing a part of refrigerant introduced into a compression chamber to be bypassed to a low-pressure space during a compression process (see
Patent Literature 1, for example). The slide valve is disposed on an outer circumference of the screw rotor, and is movable in the axial direction of the screw rotor. - As described above, the slide valve is provided on the outer circumference of the screw rotor to be movable in the axial direction of the screw rotor, and a gap opens up between a casing body side (hereinafter referred to as the back surface side) of the slide valve and a slide valve side of the casing body.
- Further, a screw rotor-side surface (hereinafter referred to as the inner circumferential surface) of the slide valve is normally disposed to be located outside in the radial direction of an inner circumferential surface of the cylinder chamber to prevent mutual contact between the slide valve and the screw rotor. Consequently, the gap between the inner circumferential surface of the slide valve and the outer circumferential surface of the screw rotor is greater than the gap between an inner circumferential surface of the cylinder and the outer circumferential surface of the screw rotor.
- In the screw compressor, the back surface side and the inner circumferential surface side of the slide valve each have a structurally necessary gap, as described above. Through these gaps, more than a small amount of refrigerant inevitably leaks from a discharge pressure (high pressure) side to a suction pressure (low pressure) side, degrading performance.
- A technique of eliminating or reducing the refrigerant leakage from the inner circumferential surface of the slide valve includes a covering member provided to the inner circumferential surface of the slide valve to fill the gap between the inner circumferential surface of the slide valve and the outer circumferential surface of the screw rotor (see
Patent Literature 2, for example).
US3314597A relates to a screw compressor which comprises a casing provided with a Working space comprising two intersecting cylindrical 'bores with parallel axes located between a low pressure and a high pressure end wall enclosing two cooperating rotors provided with helical lands and intervening grooves having a wrap angle of less than 360, which rotors are sealingly surrounded by said bores.DE102011051730A1 discloses a screw compressor housing having screw rotor bores, screw rotors, a drive for the screw rotors, and a slider in a slider receptacle for adjusting a volume ratio of the screw compressor and which extends in a direction towards the high-pressure outlet in a guide trough of the slider receptacle that is open towards the screw rotor bores and which is capable of being positioned in a first position and a second position, wherein the volume ratio of the screw compressor is greater in one of the positions than in the other of the positions, the slider connected to a first cylinder element and cooperates with a second cylinder element, the cylinder elements being at least partially arranged in the insertion space and arranged following the slider in the displacement direction thereof on a side of the slider that is opposite the high-pressure outlet. -
- Patent Literature 1:
Japanese Unexamined Patent Application Publication No. 2004-316586 - Patent Literature 2:
Japanese Patent No. 4103709 - With the covering member provided to the inner circumferential surface of the slide valve, the technique of
Patent Literature 2 described above eliminates or reduces the gap between the inner circumferential surface of the slide valve and the outer circumferential surface of the screw rotor, thereby eliminating or reducing the refrigerant leakage from the inner circumferential surface side of the slide valve, as described above. The technique ofPatent Literature 2, however, does not eliminate or reduce the refrigerant leakage from the gap on the back surface side of the slide valve. - The casing body is formed with a partition wall that separates the discharge pressure (high pressure) side and the suction pressure (low pressure) side from each other (hereinafter referred to as the high-low pressure partition wall), and an inner circumferential side of the high-low pressure partition wall faces the back surface side of the slide valve. Further, a gap is opened up between the back surface of the slide valve and an inner circumferential surface of the high-low pressure partition wall to prevent mutual contact with each other. From this gap, the refrigerant leaks owing to the pressure difference between the discharge pressure (high pressure) and the suction pressure (low pressure) at a boundary of the high-low pressure partition wall. The pressure difference tends to be increased particularly in high-pressure refrigerant, such as R410A, substantially degrading performance due to the refrigerant leakage from the back surface side of the slide valve.
- The present invention has been made to solve the above-described problems, and aims to provide a highly efficient screw compressor that eliminates or reduces the refrigerant leakage from the gap between the back surface of the slide valve and the inner circumferential surface of the high-low pressure partition wall.
- A screw compressor according to the invention is defined by the independent claim of the application. According to an embodiment of the present invention includes a casing body, a screw rotor disposed to rotate inside the casing body, a slide valve movably provided between the casing body and the screw rotor, a partition wall provided to face a back surface side of the slide valve and configured to divide an interior of the casing body into a discharge pressure space and a suction pressure space, and an injection mechanism configured to supply oil to a gap between an inner circumferential surface of the partition wall and the back surface side of the slide valve to seal the gap.
- An embodiment of the present invention eliminates or reduces the refrigerant leakage from the gap between the back surface of the slide valve and the inner circumferential surface of the high-low pressure partition wall, and improves the performance of the screw compressor.
- In the following, various embodiments are described.
Embodiments Embodiment 3 is according to the invention, whileembodiment 1 does not comprise a first oil groove of the invention, and thus it does not fall within the scope of the claims but it is useful for understanding the invention. - [
Fig. 1] Fig. 1 is a schematic configuration diagram of a refrigeration apparatus including a screw compressor according toEmbodiment 1 of the present disclosure. - [
Fig. 2] Fig. 2 is a schematic configuration diagram of the screw compressor according toEmbodiment 1 of the present disclosure. - [
Fig. 3] Fig. 3 is an illustrative diagram of an operation of a conventional screw compressor illustrated for comparison with an operation ofEmbodiment 1. - [
Fig. 4] Fig. 4 is a diagram illustrating a refrigerant leakage passage of a conventional slide valve, viewed from a back surface side of the slide valve, illustrated for comparison with a slide valve ofEmbodiment 1. - [
Fig. 5] Fig. 5 is an illustrative diagram of the operation of the screw compressor according toEmbodiment 1 of the present disclosure. - [
Fig. 6] Fig. 6 is a perspective view illustrating an oil passage of the slide valve of the screw compressor according toEmbodiment 1 of the present disclosure, with the slide valve viewed from a back surface side of the slide valve. - [
Fig. 7] Fig. 7 is a perspective view of the slide valve of the screw compressor according toEmbodiment 1 of the present disclosure, with the slide valve viewed from an inner surface side of the slide valve. - [
Fig. 8] Fig. 8 is a plan view of the slide valve of the screw compressor according toEmbodiment 1 of the present disclosure, with the slide valve viewed from the back surface side of the slide valve. - [
Fig. 9] Fig. 9 is a view of the slide valve inFig. 6 , with the slide valve vertically reversed and viewed in the direction of arrow X (in a direction in which asump 14m is visible). - [
Fig. 10] Fig. 10 is a sectional view taken along line A-A inFig. 9 . - [
Fig. 11] Fig. 11 is a sectional view taken along line B-B inFig. 9 . - [
Fig. 12] Fig. 12 is a schematic diagram illustrating main parts of a screw compressor according toEmbodiment 2 of the present disclosure. - [
Fig. 13] Fig. 13 is a perspective view of a slide valve of the screw compressor according toEmbodiment 2 of the present disclosure, with the slide valve viewed from a backside of the slide valve. - [
Fig. 14] Fig. 14 is a perspective view of a slide valve of a screw compressor according toEmbodiment 3 of the present invention. - [
Fig. 15] Fig. 15 is an illustrative diagram of the positional relationship between a high-low pressure partition wall and screw grooves corresponding to a stop position of the slide valve of the screw compressor according toEmbodiment 3 of the present invention. - [
Fig. 16] Fig. 16 is a perspective view of a slide valve of a screw compressor according toEmbodiment 4 of the present disclosure. - [
Fig. 17] Fig. 17 is a diagram illustrating a structure of a slide valve of a screw compressor according to Embodiment 5 of the present disclosure. -
Fig. 1 is a schematic configuration diagram of a refrigeration apparatus including a screw compressor according toEmbodiment 1 of the present disclosure. As illustrated inFig. 1 , the refrigeration apparatus includes devices such as ascrew compressor 1, a condenser 5, anexpansion valve 6, and anevaporator 7. Further, thescrew compressor 1 includes acompression unit 2, amotor 3 connected in series with thecompression unit 2 to drive thecompression unit 2, and anoil separator 4. In thescrew compressor 1, refrigerating machine oil (hereinafter referred to as the oil) is mixed in refrigerant discharged from thecompression unit 2, and thus theoil separator 4 separates the refrigerant and the oil from each other. The separated oil is returned to thecompression unit 2 by the pressure difference. AlthoughFig. 1 illustrates the specifications of thescrew compressor 1 including theoil separator 4 inside thescrew compressor 1, theoil separator 4 may be configured to be disposed separately outside thescrew compressor 1. -
Fig. 2 is a schematic configuration diagram of the screw compressor according toEmbodiment 1 of the present disclosure. - As illustrated in the schematic configuration in
Fig. 2 , the screw compressor includes atubular casing body 8, ascrew rotor 9 housed inside thecasing body 8, and themotor 3 that drives thescrew rotor 9 to rotate. Themotor 3 is formed of astator 3a inscribed in and fixed to thecasing body 8 and amotor rotor 3b disposed inside thestator 3a. Thescrew rotor 9 and themotor rotor 3b are both disposed on the same axis and fixed to ascrew shaft 10. - Further, the
screw rotor 9 has an outer circumferential surface formed with a plurality of helical grooves (screw grooves) 11a, and is coupled to and driven to rotate by themotor rotor 3b fixed to thescrew shaft 10. Further, the space inside thescrew grooves 11a is surrounded by an inner tubular surface of thecasing body 8 and a pair of gate rotors (not illustrated) that are in meshing engagement with thescrew grooves 11a, thereby forming acompression chamber 11. Further, the interior of thecasing body 8 is divided into a discharge pressure side and a suction pressure side by a high-lowpressure partition wall 17. The high-lowpressure partition wall 17 is provided to thecasing body 8 to face acasing body 8 side of a later-describedslide valve 14. Further, the discharge pressure side of thecasing body 8 is formed with a pair ofdischarge ports 13, which open to adischarge chamber 12. - Further, the
casing body 8 includes theslide valve 14. Theslide valve 14 is connected to arod 15 of a drivingdevice 16, and is movable in the axial direction of thescrew rotor 9. Theslide valve 14, which forms a part of thedischarge ports 13, is a mechanism that changes a discharge start (compression completion) position of high-pressure gas compressed in thecompression chamber 11, thereby changing a discharge opening time and changing an internal volume ratio. - Herein, the internal volume ratio refers to the ratio between the volume of the
compression chamber 11 at suction completion (compression start) time and the volume of thecompression chamber 11 immediately before discharge. Although two ormore slide valves 14 may be provided, the illustration of theslide valves 14 other than one is omitted. In the following, thecasing body 8 side and ascrew rotor 9 side of theslide valve 14 will be referred to as the "back surface side" and the "inner circumferential side," respectively. - A description will be given below of a conventional screw compressor for comparison with the screw compressor of
Embodiment 1. -
Fig. 3 is an illustrative diagram of an operation of the conventional screw compressor illustrated for comparison with an operation ofEmbodiment 1. Further,Fig. 4 is a diagram illustrating a refrigerant leakage passage of a conventional slide valve illustrated for comparison with the slide valve ofEmbodiment 1, with the slide valve viewed from a back surface side. - As described above, the conventional configuration allows a
slide valve 140 provided inside acasing body 80 to move in the axial direction of ascrew rotor 90. Thus, a gap opens up between aback surface 140a of theslide valve 140 and an innercircumferential surface 170a of a high-lowpressure partition wall 170, which is a part of thecasing body 80. Herein, the high-lowpressure partition wall 170 is located at a position separating a discharge pressure (high pressure) side and a suction pressure (low pressure) side from each other. Consequently, refrigerant leaks from the gap, as indicated by an arrow inFig. 3 , degrading performance. -
Embodiment 1, on the other hand, has the following configuration. -
Fig. 5 is an illustrative diagram of an operation of the screw compressor according toEmbodiment 1 of the present disclosure. Further,Fig. 6 is a perspective view illustrating an oil passage of the slide valve of the screw compressor according toEmbodiment 1 of the present disclosure, with the slide valve viewed from a back surface side of the slide valve. - As illustrated in
Figs. 5 and 6 , theslide valve 14 ofEmbodiment 1 includes aninjection mechanism 20 that injects the oil to a gap between sealing surfaces S, which define the gap between aback surface side 14f of theslide valve 14 and an innercircumferential surface 17a of the high-lowpressure partition wall 17. - The
injection mechanism 20 will be described in detail below. -
Fig. 7 is a perspective view of the slide valve of the screw compressor according toEmbodiment 1 of the present disclosure, with the slide valve viewed from an inner surface side of the slide valve.Fig. 8 is a plan view of the slide valve of the screw compressor according toEmbodiment 1 of the present disclosure, with the slide valve viewed from the back surface side of the slide valve.Fig. 9 is a view of the slide valve inFig. 6 , with the slide valve vertically reversed and viewed in the direction of arrow X (in a direction in which asump 14m is visible).Fig. 10 is a sectional view taken along line A-A inFig. 9 .Fig. 11 is a sectional view taken along line B-B inFig. 9 . InFigs. 10 and11 , arrows indicate oil passages. - Herein, a description will be given first of a basic structure of the
slide valve 14 and then of theinjection mechanism 20. As illustrated in these drawings, theslide valve 14 includes avalve body 14a, aguide portion 14b, and a connectingportion 14c that connects thevalve body 14a and theguide portion 14b. A gap communicating with thedischarge ports 13 is opened up between thevalve body 14a and theguide portion 14b to form a part of thedischarge ports 13. Further, in thevalve body 14a, a dischargeport end portion 14d of an innercircumferential side 14e on a side of thedischarge ports 13 forms a part of thedischarge ports 13, and determines the time of discharging the compressed refrigerant. That is, the dischargeport end portion 14d is moved in the axial direction of thescrew rotor 9 at the same as theslide valve 14 is moved in the axial direction of thescrew rotor 9, thereby changing the internal volume ratio. Further, theguide portion 14b has a connectinghole 15a, to which therod 15 is connected, as illustrated inFig. 2 . - As illustrated in
Fig. 11 , theslide valve 14 ofEmbodiment 1 is formed with anoil feed hole 14g passing through theslide valve 14 to inject the high-pressure oil to thescrew rotor 9. In theoil feed hole 14g, a screw rotor portionoil supply port 14i serving as an oil inflow-side opening is located on theback surface side 14f of theslide valve 14, and a screw rotor portionoil feed port 14h serving as an oil outflow-side opening is located on the innercircumferential side 14e of theslide valve 14. The hole shape and the number of theoil feed hole 14g are not limited. - Further, as illustrated in
Figs. 5 ,8, 9, and 10 , theslide valve 14 ofEmbodiment 1 is formed with anoil feed hole 14j to inject the oil to the gap (between the sealing surfaces S) between the high-lowpressure partition wall 17 and theback surface side 14f of theslide valve 14. In theoil feed hole 14j, a slide valve back surface portion oil supply port 14l serving as an oil inflow-side opening of theoil feed hole 14j is located on theback surface side 14f of theslide valve 14. Further, as illustrated inFig. 5 , a slide valve back surface portionoil feed port 14k serving as an oil outflow-side opening of theoil feed hole 14j is located in a portion, facing the high-lowpressure partition wall 17, of theback surface side 14f of theslide valve 14, that is, within the range of the sealing surfaces S. The hole shape and the number of theoil feed hole 14j are not limited. Theoil feed hole 14j corresponds to a first oil feed hole of the present invention. - Further, the
slide valve 14 is formed with thesump 14m recessed on theback surface side 14f. As illustrated inFig. 9 , the screw rotor portionoil supply ports 14i and the slide valve back surface portion oil supply port 14l are located in thesump 14m. - Flows of the oil will be described below.
- In the
screw compressor 1 according toEmbodiment 1, the high-pressure oil is injected to a gap between the innercircumferential side 14e of theslide valve 14 and a portion facing the innercircumferential side 14e and a gap between theback surface side 14f of theslide valve 14 and a portion facing theback surface side 14f to eliminate or reduce the refrigerant leakage from thescrew rotor 9 and prevent burning. - Herein, the injection on the inner
circumferential side 14e of theslide valve 14 will first be described. As illustrated inFig. 1 , the high-pressure oil in theoil separator 4 is first supplied by the pressure difference to thesump 14m provided in theslide valve 14 via a flow passage (not illustrated) inside thecasing body 8. Subsequently, the oil supplied to thesump 14m is caused by the pressure difference to flow into theoil feed hole 14g from the screw rotor portionoil supply port 14i provided inside thesump 14m, and passes through theoil feed hole 14g. Then, the high-pressure oil is injected to thescrew rotor 9 from the screw rotor portionoil feed port 14h. - The injection on the
back surface side 14f of theslide valve 14 will next be described.Embodiment 1 is characterized in that the high-pressure oil is injected to a gap between the sealing surfaces S from theback surface side 14f. Firstly, the above-described oil in thesump 14m distributed by theoil separator 4 is used. The high-pressure oil in thesump 14m is caused by the pressure difference to flow into theoil feed hole 14j from the slide valve back surface portion oil supply port 14l provided inside thesump 14m, and passes through theoil feed hole 14j. Subsequently, the oil is injected to the gap between the sealing surfaces S from the slide valve back surface portionoil feed port 14k. Theoil feed hole 14j formed in theslide valve 14 corresponds to a part of theinjection mechanism 20 of the present invention. - In
Embodiment 1, the screw rotor portionoil supply ports 14i and the slide valve back surface portion oil supply port 14l are set to be located inside thesame sump 14m, but are not necessarily required to have this configuration, and may be configured to be located inseparate sumps 14m. Further,Embodiment 1 basically aims to reduce the refrigerant leakage on the back surface side of theslide valve 14, and theoil feed hole 14j is also applicable to theslide valve 14 not having theoil feed hole 14g. Further, the thickness of the high-lowpressure partition wall 17 may be increased to cause an opening of theoil feed hole 14j to face the high-lowpressure partition wall 17 even when theslide valve 14 is moved. - As described above,
Embodiment 1 includes theinjection mechanism 20 that injects the oil to the gap between the sealing surfaces S to seal the sealing surfaces S, thereby eliminating or reducing the refrigerant leakage from the discharge pressure (high pressure) side to the suction pressure (low pressure) side. Consequently, the efficiency of thescrew compressor 1 can be improved to contribute to energy saving. - The
injection mechanism 20 is configured to have theoil feed hole 14j passing through theslide valve 14 to supply the oil flowing from the slide valve back surface portion oil supply port 14l of theoil feed hole 14j to the gap between the sealing surfaces S from the slide valve back surface portionoil feed port 14k, that is, simply configured to have a hole formed through theslide valve 14. Consequently, theinjection mechanism 20 can be configured at low cost. -
Embodiment 2 is different fromEmbodiment 1 only in the area having the oil feed hole for feeding the oil to the gap between the sealing surfaces S. -
Fig. 12 is a schematic diagram illustrating main parts of a screw compressor according toEmbodiment 2 of the present disclosure.Fig. 13 is a perspective view of a slide valve of the screw compressor according toEmbodiment 2 of the present disclosure, with the slide valve viewed from a backside of the slide valve. InEmbodiment 2, differences fromEmbodiment 1 will be described, and configurations not described inEmbodiment 2 are similar to those ofEmbodiment 1. - In
Embodiment 2, theoil feed hole 14j formed in theslide valve 14 inEmbodiment 1 is eliminated, and anoil feed hole 17b is formed in the high-lowpressure partition wall 17, which forms a part of thecasing body 8. Further, a configuration is designed in which the innercircumferential surface 17a of the high-lowpressure partition wall 17 has a slide valve back surface portionoil feed port 17c serving as an oil outflow-side opening of theoil feed hole 17b, to inject the high-pressure oil flowing into theoil feed hole 17b to the gap between the sealing surfaces S from the slide valve back surface portionoil feed port 17c. - The position of an oil inflow-side opening of the
oil feed hole 17b is not particularly limited as long as the oil inflow-side opening of theoil feed hole 17b is formed at a position at which the oil inflow-side opening is capable of receiving the oil in thescrew compressor 1. Further, the hole shape and the number of theoil feed hole 17b are not limited. Theoil feed hole 17b corresponds to a second oil feed hole of the present invention. - As described above, according to
Embodiment 2, the high-pressure oil is injected to the gap between the sealing surfaces S from the slide valve back surface portionoil feed port 17c provided in the innercircumferential surface 17a of the high-lowpressure partition wall 17. Consequently, the refrigerant leakage from the discharge pressure (high pressure) side to the suction pressure (low pressure) side in the sealing surfaces S can be eliminated or reduced, and the efficiency of thescrew compressor 1 can be improved. -
Embodiment 3 is different fromEmbodiment 1 only in that an oil groove is provided in theback surface side 14f of theslide valve 14. -
Fig. 14 is a perspective view of a slide valve of a screw compressor according toEmbodiment 3 of the present invention. InEmbodiment 3, differences fromEmbodiment 1 will be described, and configurations not described inEmbodiment 3 are similar to those ofEmbodiment 1. - In
Embodiment 3, theback surface side 14f of thevalve body 14a of theslide valve 14 is formed with anoil groove 18 extending in the circumferential direction of theback surface side 14f to efficiently spread the oil injected to the gap between the sealing surfaces S inEmbodiment 1 over the sealing surfaces S. The position of processing theoil groove 18 is set to correspond within the range of the sealing surfaces S. Theoil groove 18 corresponds to a first oil groove of the present invention. The sectional shape and the number of the above-describedoil groove 18 are not limited. -
Fig. 15 is an illustrative diagram of the positional relationship between the high-low pressure partition wall and the screw grooves corresponding to a stop position of the slide valve of the screw compressor according toEmbodiment 3 of the present invention. As illustrated inFig. 15 , theoil groove 18 may extend across more than one of thescrew grooves 11a, depending on a sliding position of theslide valve 14. The pressures in thescrew grooves 11a are different from each other. When theoil groove 18 thus extends across more than one of thescrew grooves 11a, theoil groove 18 may allow communication between a high pressure-side screw groove 11a and a low pressure-side screw groove 11a and cause refrigerant leakage from the high-pressure side to the low-pressure side. To prevent theoil groove 18 from thus forming a refrigerant leakage passage, theoil groove 18 is not limited to the configuration in which theoil groove 18 is provided over the entirety in the circumferential direction of theback surface side 14f of theslide valve 14, and an area not processed to form a groove may be left in theback surface side 14f. - With the
oil groove 18 thus provided, the oil injected to the gap between the sealing surfaces S from the slide valve back surface portionoil feed port 14k efficiently spreads over the sealing surfaces S. - The area having the
oil groove 18 is not limited to theback surface side 14f of theslide valve 14, and may be the innercircumferential surface 17a of the high-lowpressure partition wall 17 forming a part of the sealing surfaces S, or may be both theback surface side 14f and the innercircumferential surface 17a. When an oil groove is to be provided in the innercircumferential surface 17a of the high-lowpressure partition wall 17, the oil groove is formed to extend in the circumferential direction of the innercircumferential surface 17a similarly to theoil groove 18. The oil groove thus provided in the innercircumferential surface 17a of the high-lowpressure partition wall 17 corresponds to a third oil groove of the present invention. - As described above, according to
Embodiment 3, effects similar to those ofEmbodiment 1 are obtained, and the following effects are obtained. That is, the oil injected to the gap between the sealing surfaces S from theback surface side 14f of theslide valve 14 is more likely to spread over the entire circumference of the back surface of the slide valve through theoil groove 18. With theoil groove 18,Embodiment 3 is more capable of eliminating or reducing the refrigerant leakage from the discharge pressure (high pressure) side to the suction pressure (low pressure) side in the sealing surfaces S than in a case in which the configuration of Embodiment 1 (the configuration having the slide valve back surface portionoil feed port 14k) is implemented alone. Consequently, the efficiency of thescrew compressor 1 can be further improved. -
Embodiment 4 corresponds to a configuration combining the configuration ofEmbodiment 2 and the configuration ofEmbodiment 3. That is, theoil groove 18 is provided to theslide valve 14 of thescrew compressor 1 ofEmbodiment 2, which is characterized in that the oil is injected to the gap between the sealing surfaces S from the side of the high-lowpressure partition wall 17. Features such as the shape of theoil groove 18 and the position at which theoil groove 18 is formed are similar to those ofEmbodiment 3. -
Fig. 16 is a perspective view of a slide valve of a screw compressor according toEmbodiment 4 of the present disclosure. InEmbodiment 4, differences fromEmbodiment 2 will be described, and configurations not described inEmbodiment 4 are similar to those ofEmbodiment 2. - The oil injected to the gap between the sealing surfaces S from the side of the high-low
pressure partition wall 17, as indicated by a solid-white arrow inFig. 16 , flows along theoil groove 18, as indicated by solid arrows, and efficiently spreads over the sealing surfaces S. - As described above, according to
Embodiment 4, effects similar to those ofEmbodiment 2 are obtained, and the following effects are obtained. That is, the oil injected to the gap between the sealing surfaces S from the side of the high-lowpressure partition wall 17 is more likely to spread over the entire circumference of the back surface of the slide valve through theoil groove 18. With the action of theoil groove 18,Embodiment 4 is more capable of eliminating or reducing the refrigerant leakage from the discharge pressure (high pressure) side to the suction pressure (low pressure) side in the sealing surfaces S than in a case in which the configuration of Embodiment 2 (the configuration in which the oil is injected to the gap between the sealing surfaces S from the side of the high-low pressure partition wall 17) is implemented alone. Consequently, the efficiency of thescrew compressor 1 can be further improved. - Embodiment 5 is characterized in allowing communication between the
sump 14m and theoil groove 18. -
Fig. 17 is a diagram illustrating a structure of a slide valve of a screw compressor according to Embodiment 5 of the present disclosure. - The
slide valve 14 ofEmbodiment 1 illustrated inFig. 9 described above is configured to cause the oil in thesump 14m to pass through thevalve body 14a with theoil feed hole 14j to inject the oil to the gap between the sealing surfaces S from the slide valve back surface portionoil feed port 14k. - Embodiment 5, on the other hand, is configured to cause the oil to flow along the back surface side (the outer circumferential surface) of the
slide valve 14 to inject the oil to the gap between the sealing surfaces S. Specifically, theoil feed hole 14j ofEmbodiment 1 is eliminated, and anoil groove 18a is provided to communicate with thesump 14m to inject the high-pressure oil in thesump 14m to the gap between the sealing surfaces S through theoil groove 18a. Theoil groove 18a of Embodiment 5 is different from theoil groove 18 ofEmbodiment 3 only in that theoil groove 18 communicates with thesump 14m, and is similar to theoil groove 18 ofEmbodiment 3 in the other features. Theoil groove 18a corresponds to a second oil groove of the present invention. - As described above, according to Embodiment 5, the high-pressure oil in the
sump 14m can be caused to spread over the sealing surfaces S without theoil feed hole 14j as inEmbodiments 1 to 4, which passes through theslide valve 14. Consequently, the refrigerant leakage can be eliminated or reduced and efficiency of thescrew compressor 1 can be improved with a simpler configuration. -
Embodiments 1 to 5 may be combined as appropriate. For example,Embodiment 1 andEmbodiment 2 may be combined to inject the oil to the gap between the sealing surfaces S from both theback surface side 14f of theslide valve 14 and the innercircumferential surface 17a of the high-lowpressure partition wall 17. - Further,
Embodiments 1 to 5 are applicable to any screw compressor including a mechanism that has a gap between theback surface side 14f of theslide valve 14 and the innercircumferential surface 17a of the high-lowpressure partition wall 17. For example, although the above description has been given of a single-stage screw compressor including onecompression unit 2, the compressor may be a multi-stage compressor including two ormore compression units 2. Further, the present invention is useful not only in a screw compressor of constant speed specifications but also in an inverter-driven screw compressor. - In
Embodiments 1 to 5, the description has been given of theslide valve 14 capable of changing the internal volume ratio. However, the slide valve to which the present invention is applicable is not limited to the slide valve capable of changing the internal volume ratio. For example, the slide valve to which the present invention is applicable may be a volume-control slide valve allowing a part of the refrigerant gas to be bypassed to the suction side (low pressure), or may be an immovable slide valve fixed to thecasing body 8. - 1
screw compressor 2compression unit 3motor 3a stator3b motor rotor 4 oil separator 5condenser 6expansion valve 7evaporator 8casing body 9screw rotor 10screw shaft 11compression chamber 11a screw groove 12discharge chamber 13discharge port 14slide valve 14a valve body 14b guide portion 14c connecting portion 14d dischargeport end portion 14e innercircumferential side 14f backsurface side 14goil feed hole 14h screw rotor portionoil feed port 14i screw rotor portionoil supply port 14joil feed hole 14k slide valve back surface portion oil feed port 14l slide valve back surface portionoil supply 15port 14m sumprod 15a connecting hole 16driving device 17 high-lowpressure partition wall 17a innercircumferential surface 17boil feed hole 17c slide valve back surface portionoil feed port 18oil groove 18a oil groove 20injection mechanism 80casing body 90screw rotor 140slide valve 140a backsurface 170 high-lowpressure partition wall 170a inner circumferential surface S sealing surface
Claims (6)
- A screw compressor comprising:a casing body (8);a screw rotor (9) disposed to rotate inside the casing body (8);a slide valve (14) movably provided between the casing body (8) and the screw rotor (9);a partition wall (17) provided to face a back surface side (14f) of the slide valve (14) and configured to divide an interior of the casing body (8) into a discharge pressure space and a suction pressure space; andan injection mechanism (20) configured to supply oil to a gap between an inner circumferential surface (17a) of the partition wall (17) and the back surface side (14f) of the slide valve (14) to seal the gap,the injection mechanism (20) being configured to have at least one first oil feed hole (14j) formed to pass through the slide valve (14) and at least one oil feed port (14k) serving as an oil outflow-side opening of the at least one first oil feed hole (14j), one end of the at least one first oil feed hole (14j) facing the partition wall (17) and configured to supply the oil to the gap from the opening-wherein the injection mechanism (20) further has a first oil groove (18) provided in the back surface side (14f) of the slide valve (14) to face the partition wall (17) and configured to distribute the oil supplied to the gap, the first oil groove (18) and the at least one first oil feed hole (14j) communicating with each other via the at least one oil feed port (14k) to supply the oil to the gap from the first oil groove (18),wherein the first oil groove (18) extends in a circumferential direction of the back surface side (14f).
- The screw compressor of claim 1, wherein the slide valve (14) has a sump (14m) recessed on the back surface side (14f), and an other end of the at least one first oil feed hole (14j) opens to the sump (14m).
- The screw compressor of claim 2, the sump (14m) and the first oil groove (18) communicating with each other to supply the oil in the sump (14m) to the gap from the first oil groove (18).
- The screw compressor of any one of claims 1 to 3, wherein the injection mechanism (20) is configured to have at least one second oil feed hole (17b) formed in the partition wall (17), one end of the at least one second oil feed hole (17b) opening to the inner circumferential surface (17a) of the partition wall (17) to supply the oil to the gap.
- The screw compressor of any one of claims 1 to 4, wherein the injection mechanism (20) further has a third oil groove provided in the inner circumferential surface (17a) of the partition wall (17) and configured to distribute the oil supplied to the gap.
- The screw compressor of claim 5, wherein the third oil groove is provided in the inner circumferential surface (17a) of the partition wall (17) and extends in a circumferential direction of the inner circumferential surface (17a).
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2015/052275 WO2016121021A1 (en) | 2015-01-28 | 2015-01-28 | Screw compressor |
Publications (3)
Publication Number | Publication Date |
---|---|
EP3252310A1 EP3252310A1 (en) | 2017-12-06 |
EP3252310A4 EP3252310A4 (en) | 2018-10-10 |
EP3252310B1 true EP3252310B1 (en) | 2024-04-03 |
Family
ID=56542677
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP15879918.9A Active EP3252310B1 (en) | 2015-01-28 | 2015-01-28 | Screw compressor |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP3252310B1 (en) |
CN (1) | CN207333184U (en) |
TW (1) | TWI579464B (en) |
WO (1) | WO2016121021A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP7112031B2 (en) * | 2019-03-01 | 2022-08-03 | 三菱電機株式会社 | screw compressor |
US11802563B2 (en) * | 2019-11-26 | 2023-10-31 | Mitsubishi Electric Corporation | Screw compressor |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NO117317B (en) * | 1964-03-20 | 1969-07-28 | Svenska Rotor Maskiner Ab | |
DE1804884A1 (en) * | 1968-10-24 | 1970-09-17 | Gutehoffnungshuette Sterkrade | Screw compressor with two interlocking screw rotors and an axially adjustable control slide for flow control and single injection |
JPS5147051Y2 (en) * | 1972-12-08 | 1976-11-13 | ||
JPS5147051U (en) * | 1974-10-05 | 1976-04-07 | ||
JPH05106572A (en) * | 1991-10-17 | 1993-04-27 | Daikin Ind Ltd | Single shaft type screw compressor |
EP2623789B1 (en) * | 2010-09-30 | 2019-08-14 | Daikin Industries, Ltd. | Screw compressor |
DE102011051730A1 (en) * | 2011-07-11 | 2013-01-17 | Bitzer Kühlmaschinenbau Gmbh | screw compressors |
JP5865056B2 (en) * | 2011-12-16 | 2016-02-17 | 三菱電機株式会社 | Screw compressor |
-
2015
- 2015-01-28 WO PCT/JP2015/052275 patent/WO2016121021A1/en active Application Filing
- 2015-01-28 CN CN201590001327.9U patent/CN207333184U/en not_active Expired - Fee Related
- 2015-01-28 EP EP15879918.9A patent/EP3252310B1/en active Active
- 2015-04-09 TW TW104111381A patent/TWI579464B/en not_active IP Right Cessation
Also Published As
Publication number | Publication date |
---|---|
WO2016121021A1 (en) | 2016-08-04 |
EP3252310A4 (en) | 2018-10-10 |
TW201627577A (en) | 2016-08-01 |
CN207333184U (en) | 2018-05-08 |
EP3252310A1 (en) | 2017-12-06 |
TWI579464B (en) | 2017-04-21 |
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