US20070003421A1 - Two-stage screw compressor - Google Patents
Two-stage screw compressor Download PDFInfo
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- US20070003421A1 US20070003421A1 US11/442,354 US44235406A US2007003421A1 US 20070003421 A1 US20070003421 A1 US 20070003421A1 US 44235406 A US44235406 A US 44235406A US 2007003421 A1 US2007003421 A1 US 2007003421A1
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- casing
- pressure stage
- low pressure
- discharge
- screw compressor
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Classifications
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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
- 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
- F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
- F04C23/001—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids of similar working principle
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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
- F04C29/06—Silencing
- F04C29/068—Silencing the silencing means being arranged inside the pump housing
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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
- F04C29/02—Lubrication; Lubricant separation
- F04C29/026—Lubricant separation
Definitions
- the present invention relates to a two-stage screw compressor used for a screw refrigerator or the like.
- a fundamental frequency obtained by multiplying the number of teeth of a male rotor by a rotational frequency, and a higher harmonic component of the fundamental frequency constitute a dominant peak.
- various measures such as sticking a noise absorbing material to a casing, enhancing sound insulation performance by forming a casing to have a double structure, or enhancing rigidity of a casing by adding a rib thereto have been taken.
- a single-stage single screw compressor there is the one in which a resonance space is provided inside a slide valve so as to communicate with a compression space to reduce the noise, as shown in JP-A-2005-30362.
- the measures according to the means such as sticking the noise absorbing material to the casing, forming the casing into the double structure, and adding the rib to the casing show a certain degree of noise reduction effect.
- the means according to the double structure of the casing and the rib addition there are the problems of complication of the cast shape and increase in the cast weight.
- any of the above described prior arts does not take account of increase in noise due to internal resonance in a discharge casing in a two-stage screw compressor, which includes a low pressure stage casing provided with a low pressure stage compression mechanism, the discharge casing provided on a discharge side of the low pressure stage casing, a high pressure stage casing provided with a high pressure stage compression mechanism, and an intermediate stage casing for connecting the discharge casing and the high pressure stage casing and accommodating an electric motor.
- An object of the present invention is to prevent internal resonance occurring in a discharge casing by means of a simple structure, and thereby realize reduction in noise, in a two-stage screw compressor as described above.
- the present invention provides a two-stage screw compressor including: a low pressure stage casing for accommodating a low pressure stage compression mechanism and a bearing member, which low pressure stage casing is provided with a capacity control part constituted by a slide valve, a rod and a piston; a discharge casing provided on a discharge side of the aforesaid low pressure stage casing for accommodating a bearing member supporting the low pressure stage compression mechanism; a high pressure stage casing for accommodating a high pressure stage compression mechanism and a bearing member; and an intermediate stage casing for connecting the aforesaid discharge casing and the aforesaid high pressure stage casing, and accommodating an electric motor, wherein a cavity is formed on a discharge casing side in the slide valve so as to enlarge the capacity of a discharge space formed in the aforesaid discharge casing, so that internal resonance occurring in the discharge casing is prevented.
- porous material it is more effective to provide a porous material in the cavity formed in the slide valve.
- the porous material it is suitable to use a demister constructed by arranging a plurality of metal wires in a net form.
- the porous material may be constructed by glass wool.
- Another characteristic of the present invention is, in the above described two-stage screw compressor, that the length in an axial direction of a discharge space formed in the aforesaid discharge casing is enlarged by forming the cavity on the discharge casing side in the slide valve so as not to correspond to a wavelength of noise generated by the low pressure stage compression mechanism.
- the wavelength of the noise generated by the low pressure stage compression mechanism is based on a meshing frequency of rotors, which meshing frequency is a frequency including a fundamental frequency obtained by multiplying the number of teeth of a male rotor by a rotational frequency, and a higher harmonic component of the fundamental frequency, and it is desirable to enlarge the length in the axial direction of the discharge space formed in the aforesaid discharge casing by forming the cavity on the discharge casing side in the slide valve so as not to correspond to any of the wavelengths based on the above described frequencies.
- a cavity is formed on a discharge casing side in the slide valve to enlarge the capacity of a discharge space formed in the discharge casing, and thereby internal resonance occurring in the discharge casing is prevented. Therefore, the internal resonance occurring in the discharge casing is prevented with a simple structure and significant noise reduction can be realized.
- FIG. 1 is a vertical sectional view of a two-stage screw compressor showing one embodiment of the present invention
- FIG. 2 is a vertical sectional view of a main part of a two-stage screw compressor showing another embodiment of the present invention.
- FIG. 3 is a noise spectrum diagram for explaining the effect of the present invention.
- FIG. 1 shows one embodiment of a two-stage screw compressor of the present invention.
- the screw compressor includes a low pressure stage casing 1 having an inlet opening 26 , a discharge casing 2 connected to a discharge side of the low pressure stage casing 1 and having a gas passage 38 , a motor cover (intermediate stage casing) 3 which is connected to a downstream side of the discharge casing 2 , has a gas passage 39 , and accommodates a coil end 8 of an electric motor 7 , a motor casing (intermediate stage casing) 4 accommodating the electric motor 7 , and a high pressure stage casing 5 having a discharge port 40 .
- These members are connected with bolts or the like to be integrated.
- a low pressure stage casing 1 there are formed a cylindrical bore 31 , an inlet port 29 which introduces a refrigerant gas into the cylindrical bore 31 , a piston chamber 33 which accommodates a piston 21 for driving a slide valve 23 , and the like.
- a low pressure stage side male rotor 6 which is rotatably supported with roller bearings 11 and 12 and a ball bearing 17 , and a low pressure stage side female rotor (not shown) are accommodated so as to mesh with each other.
- a shaft of the low pressure stage side male rotor 6 is connected to a shaft of the high pressure stage side male rotor 9 by a gear coupling 45 .
- the piston 21 accommodated in the above described piston chamber 33 is connected to the slide valve 23 via a rod 22 .
- a gas passage 38 which allows the cylindrical bore 31 and the above described motor cover 3 to communicate with each other.
- a gas passage 39 which allows the discharge casing 2 and the motor casing 4 to communicate with each other.
- an inlet chamber 28 which introduces the refrigerant gas to the high pressure stage casing 5 .
- the high pressure stage casing 5 there is formed a cylindrical bore 32 , in which the high pressure stage side male rotor 9 which is rotatably supported with roller bearings 13 and 14 and a ball bearing 19 , and a high pressure stage side female rotor (not shown) are accommodated so as to mesh with each other.
- the shaft of the high pressure stage side male rotor 9 is directly connected to the electric motor 7 .
- the refrigerant gas at low temperature and low pressure which has been sucked from the inlet opening 26 provided in the low pressure stage casing 1 is sucked from the intake port 29 formed in the low pressure stage casing 1 into a compression chamber formed by surfaces of the meshing teeth of the male and female screw rotors on the low pressure stage side and the low pressure stage casing 1 .
- the refrigerant gas is sealed in the compression chamber formed by the meshing tooth surfaces of the male and female screw rotors on the low pressure stage side and the low pressure stage casing 1 as the low pressure stage side male rotor 6 connected to the electric motor 7 is rotated, and is gradually compressed by reduction of the compression chamber to become a gas at high temperature and at high pressure, which is discharged from the discharge port 34 to the gas passage 38 of the discharge casing 2 and further, passes through the gas passage 39 formed in the motor cover 3 to flow into the motor casing 4 .
- the refrigerant gas having flown into the motor casing 4 passes through an air gap between motor rotors, and is sucked from the intake chamber 28 formed in the motor casing 4 to a compression chamber formed by surfaces of the meshing teeth of the male and female screw rotors on the high pressure stage side, the motor casing 4 , and the high pressure stage casing 5 .
- the refrigerant gas is sealed in the compression chamber formed by the meshing tooth surfaces of the male and female screw rotors on the high pressure stage side, the motor casing 4 , and the high pressure stage casing 5 as the high pressure stage side male rotor 9 directly connected to the electric motor 7 is rotated, and is gradually compressed by reduction in the compression chamber to become a gas at higher temperature and at higher pressure than before being compressed, which is discharged into the discharge passage 40 of the high pressure side casing 5 .
- the radial load derived from compression reaction force acting on the male and female screw rotors on the low pressure stage side during compression, is supported by the roller bearings 11 and 12 , and the thrust load derived from the compression reaction force is supported by the ball bearing 17 .
- the radial load is supported by the roller bearings 13 and 14 , and the thrust load is supported by the ball bearing 19 .
- Lubricating oil for these bearings is supplied through an oil passage communicating with bearing parts provided in the low pressure stage casing 1 , the discharge casing 2 , the motor cover 3 , the motor casing 4 and the high pressure stage casing 5 , respectively.
- a fundamental frequency obtained by multiplying the number of teeth of a male rotor by a rotational frequency, and a higher harmonic component (hereinafter, referred to as a meshing frequency) of the fundamental frequency constitute a dominant peak.
- the discharge casing 2 and the intermediate stage casings (the motor cover 3 , the motor casing 4 ) are required for connecting the low pressure stage casing 1 on the low pressure stage side and the high pressure stage casing 5 on the high pressure stage side.
- the gas passage 38 and the gas passage 39 are formed in the discharge casing 2 and the intermediate stage casing (motor cover 3 ), respectively, as spaces. If the length of these spaces 38 and 39 and the wavelength of the meshing frequency correspond to each other, a noise level increases due to internal resonance.
- a cavity 48 is formed on a discharge casing side (gas passage side) in the slide valve 23 .
- the length in an axial direction of the discharge space corresponds to the wavelength of the meshing frequency of the rotors, the internal resonance occurs to increase the noise level, however, by providing the above described cavity 48 , the length in the axial direction of the discharge space can be extended so as not to correspond to the wavelength of the meshing frequency of the rotors.
- the length in the axial direction of the cavity 48 formed in the slide valve 23 may be extended to half or more of the length in an axial direction of the slide valve, and thereby, the effect of reliably preventing the internal resonance can be obtained.
- FIG. 2 shows another embodiment of the present invention.
- a porous material 49 is provided in the cavity 48 formed in the slide valve 23 .
- the porous material 49 may be anything as long as it has an oil resistance property and a refrigerant resistance property, but extremely high noise reduction effect can be obtained by adopting a demister or glass wool.
- the demister in this case means the one which is given the function as a porous material by arranging a plurality of metal wires in a meshed form.
- FIG. 3 is a noise spectrum diagram for explaining the effect of the present invention.
- the length in the axial direction of the space formed as the gas passages 38 and 39 , and the wavelength of a fifth order component ( 5 f ) of the meshing frequency correspond to each other, and thus the fifth order component ( 5 f ) becomes a dominant peak due to a resonance phenomenon.
- the cavity 48 is provided in the slide valve 23 , the space formed as the gas passages 38 and 39 can be enlarged.
- the length in the axial direction of the entire enlarged space does not correspond to the wavelength of the fifth order component ( 5 f ) of the meshing frequency, and therefore, it becomes possible to avoid the resonance phenomenon. Accordingly, it becomes possible to reduce the peak of the fifth order component ( 5 f ) significantly, so that significant noise reduction effect can be obtained.
- the noise data shown in FIG. 3 is only one example.
- the peak which can be decreased by applying the present invention depends on the length in the axial direction of the discharge space and on the wavelength of the meshing frequency, and thus the fifth order component ( 5 f ) does not always become the dominant peak.
- whatever order component constitutes the dominant peak it is possible to extend the length in the axial direction of the discharge space by forming the cavity 48 in the slide valve 23 , so as not to correspond to the wavelength of the frequency component at which the resonance occurs, which can reduce noise.
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- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Applications Or Details Of Rotary Compressors (AREA)
Abstract
Description
- The present application claims priority from Japanese application JP 2005-190879 filed on Jun. 30, 2005, the content of which is hereby incorporated by reference into this application.
- The present invention relates to a two-stage screw compressor used for a screw refrigerator or the like.
- Regarding a noise spectrum generated by a screw compressor, it is known that a fundamental frequency obtained by multiplying the number of teeth of a male rotor by a rotational frequency, and a higher harmonic component of the fundamental frequency constitute a dominant peak. As means of reducing the noise, various measures such as sticking a noise absorbing material to a casing, enhancing sound insulation performance by forming a casing to have a double structure, or enhancing rigidity of a casing by adding a rib thereto have been taken. As a single-stage single screw compressor, there is the one in which a resonance space is provided inside a slide valve so as to communicate with a compression space to reduce the noise, as shown in JP-A-2005-30362.
- In the above described prior arts, the measures according to the means such as sticking the noise absorbing material to the casing, forming the casing into the double structure, and adding the rib to the casing show a certain degree of noise reduction effect. However, if adopting the above described means, it is necessary to cover the entire cast casing with the noise absorbing material in the case of sticking the noise absorbing material on the casing, and thus it is often difficult in the case of a screw compressor having a complicated cast shape. Further, in the case of the means according to the double structure of the casing and the rib addition, there are the problems of complication of the cast shape and increase in the cast weight.
- In addition, any of the above described prior arts does not take account of increase in noise due to internal resonance in a discharge casing in a two-stage screw compressor, which includes a low pressure stage casing provided with a low pressure stage compression mechanism, the discharge casing provided on a discharge side of the low pressure stage casing, a high pressure stage casing provided with a high pressure stage compression mechanism, and an intermediate stage casing for connecting the discharge casing and the high pressure stage casing and accommodating an electric motor.
- An object of the present invention is to prevent internal resonance occurring in a discharge casing by means of a simple structure, and thereby realize reduction in noise, in a two-stage screw compressor as described above.
- In order to achieve the above-described object, the present invention provides a two-stage screw compressor including: a low pressure stage casing for accommodating a low pressure stage compression mechanism and a bearing member, which low pressure stage casing is provided with a capacity control part constituted by a slide valve, a rod and a piston; a discharge casing provided on a discharge side of the aforesaid low pressure stage casing for accommodating a bearing member supporting the low pressure stage compression mechanism; a high pressure stage casing for accommodating a high pressure stage compression mechanism and a bearing member; and an intermediate stage casing for connecting the aforesaid discharge casing and the aforesaid high pressure stage casing, and accommodating an electric motor, wherein a cavity is formed on a discharge casing side in the slide valve so as to enlarge the capacity of a discharge space formed in the aforesaid discharge casing, so that internal resonance occurring in the discharge casing is prevented.
- In this case, by making the length in an axial direction of the cavity formed in the slide valve half or more of the length in an axial direction of the slide valve, it becomes possible to prevent the internal resonance more reliably.
- Further, it is more effective to provide a porous material in the cavity formed in the slide valve. As the porous material, it is suitable to use a demister constructed by arranging a plurality of metal wires in a net form. Alternatively, the porous material may be constructed by glass wool.
- Another characteristic of the present invention is, in the above described two-stage screw compressor, that the length in an axial direction of a discharge space formed in the aforesaid discharge casing is enlarged by forming the cavity on the discharge casing side in the slide valve so as not to correspond to a wavelength of noise generated by the low pressure stage compression mechanism. In this case, preferably, the wavelength of the noise generated by the low pressure stage compression mechanism is based on a meshing frequency of rotors, which meshing frequency is a frequency including a fundamental frequency obtained by multiplying the number of teeth of a male rotor by a rotational frequency, and a higher harmonic component of the fundamental frequency, and it is desirable to enlarge the length in the axial direction of the discharge space formed in the aforesaid discharge casing by forming the cavity on the discharge casing side in the slide valve so as not to correspond to any of the wavelengths based on the above described frequencies.
- According to the present invention, in a two-stage screw compressor including a low pressure stage casing provided with a low pressure stage compression mechanism, a discharge casing provided on a discharge side of the low pressure stage casing, a high pressure stage casing provided with a high pressure stage compression mechanism, and intermediate stage casings for connecting the discharge casing and the high pressure stage casing, and accommodating an electric motor, a cavity is formed on a discharge casing side in the slide valve to enlarge the capacity of a discharge space formed in the discharge casing, and thereby internal resonance occurring in the discharge casing is prevented. Therefore, the internal resonance occurring in the discharge casing is prevented with a simple structure and significant noise reduction can be realized.
- Hereinafter, an embodiment of the present invention will be described based on the drawings.
- Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings.
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FIG. 1 is a vertical sectional view of a two-stage screw compressor showing one embodiment of the present invention; -
FIG. 2 is a vertical sectional view of a main part of a two-stage screw compressor showing another embodiment of the present invention; and -
FIG. 3 is a noise spectrum diagram for explaining the effect of the present invention. -
FIG. 1 shows one embodiment of a two-stage screw compressor of the present invention. The screw compressor includes a lowpressure stage casing 1 having an inlet opening 26, adischarge casing 2 connected to a discharge side of the lowpressure stage casing 1 and having agas passage 38, a motor cover (intermediate stage casing) 3 which is connected to a downstream side of thedischarge casing 2, has agas passage 39, and accommodates acoil end 8 of an electric motor 7, a motor casing (intermediate stage casing) 4 accommodating the electric motor 7, and a highpressure stage casing 5 having adischarge port 40. These members are connected with bolts or the like to be integrated. - In the low
pressure stage casing 1, there are formed acylindrical bore 31, aninlet port 29 which introduces a refrigerant gas into thecylindrical bore 31, apiston chamber 33 which accommodates apiston 21 for driving aslide valve 23, and the like. In thecylindrical bore 31, a low pressure stageside male rotor 6 which is rotatably supported withroller bearings male rotor 6 is connected to a shaft of the high pressure stage side male rotor 9 by agear coupling 45. Thepiston 21 accommodated in the above describedpiston chamber 33 is connected to theslide valve 23 via arod 22. - In the
discharge casing 2 accommodating the roller bearing 12 and the ball bearing 17 which support the shaft of the low pressure stage side rotor, there is formed agas passage 38 which allows thecylindrical bore 31 and the above describedmotor cover 3 to communicate with each other. In themotor cover 3 accommodating a ball bearing 18 which supports a rotary body on the high pressure stage side, there is formed agas passage 39 which allows thedischarge casing 2 and themotor casing 4 to communicate with each other. In themotor casing 4 accommodating the electric motor 7 and a shaft part of the high pressure stage side male rotor 9, there is formed aninlet chamber 28 which introduces the refrigerant gas to the highpressure stage casing 5. In the highpressure stage casing 5, there is formed acylindrical bore 32, in which the high pressure stage side male rotor 9 which is rotatably supported withroller bearings - Next, flows of the refrigerant gas and oil will be described. The refrigerant gas at low temperature and low pressure which has been sucked from the inlet opening 26 provided in the low
pressure stage casing 1 is sucked from theintake port 29 formed in the lowpressure stage casing 1 into a compression chamber formed by surfaces of the meshing teeth of the male and female screw rotors on the low pressure stage side and the lowpressure stage casing 1. Thereafter, the refrigerant gas is sealed in the compression chamber formed by the meshing tooth surfaces of the male and female screw rotors on the low pressure stage side and the lowpressure stage casing 1 as the low pressure stageside male rotor 6 connected to the electric motor 7 is rotated, and is gradually compressed by reduction of the compression chamber to become a gas at high temperature and at high pressure, which is discharged from thedischarge port 34 to thegas passage 38 of thedischarge casing 2 and further, passes through thegas passage 39 formed in themotor cover 3 to flow into themotor casing 4. - The refrigerant gas having flown into the
motor casing 4 passes through an air gap between motor rotors, and is sucked from theintake chamber 28 formed in themotor casing 4 to a compression chamber formed by surfaces of the meshing teeth of the male and female screw rotors on the high pressure stage side, themotor casing 4, and the highpressure stage casing 5. Thereafter, the refrigerant gas is sealed in the compression chamber formed by the meshing tooth surfaces of the male and female screw rotors on the high pressure stage side, themotor casing 4, and the highpressure stage casing 5 as the high pressure stage side male rotor 9 directly connected to the electric motor 7 is rotated, and is gradually compressed by reduction in the compression chamber to become a gas at higher temperature and at higher pressure than before being compressed, which is discharged into thedischarge passage 40 of the highpressure side casing 5. - The radial load, derived from compression reaction force acting on the male and female screw rotors on the low pressure stage side during compression, is supported by the
roller bearings roller bearings pressure stage casing 1, thedischarge casing 2, themotor cover 3, themotor casing 4 and the highpressure stage casing 5, respectively. - In a noise spectrum generated by a screw compressor, a fundamental frequency obtained by multiplying the number of teeth of a male rotor by a rotational frequency, and a higher harmonic component (hereinafter, referred to as a meshing frequency) of the fundamental frequency constitute a dominant peak. In the case of the two-stage screw compressor, the
discharge casing 2 and the intermediate stage casings (themotor cover 3, the motor casing 4) are required for connecting the lowpressure stage casing 1 on the low pressure stage side and the highpressure stage casing 5 on the high pressure stage side. Thegas passage 38 and thegas passage 39 are formed in thedischarge casing 2 and the intermediate stage casing (motor cover 3), respectively, as spaces. If the length of thesespaces - In the present invention, in order to enlarge the capacity of the spaces formed as the above described
gas passages cavity 48 is formed on a discharge casing side (gas passage side) in theslide valve 23. By forming thecavity 48, it becomes possible to avoid the internal resonance in the discharge space (gas passages 38 and 39). That is, if the length in an axial direction of the discharge space corresponds to the wavelength of the meshing frequency of the rotors, the internal resonance occurs to increase the noise level, however, by providing the above describedcavity 48, the length in the axial direction of the discharge space can be extended so as not to correspond to the wavelength of the meshing frequency of the rotors. As a result, it is possible to avoid the internal resonance by a simple structure, in which thecavity 48 is formed in theslide valve 23, and to achieve reduction in noise. The length in the axial direction of thecavity 48 formed in theslide valve 23 may be extended to half or more of the length in an axial direction of the slide valve, and thereby, the effect of reliably preventing the internal resonance can be obtained. -
FIG. 2 shows another embodiment of the present invention. In this embodiment, aporous material 49 is provided in thecavity 48 formed in theslide valve 23. By providing theporous material 49 like this, it becomes possible, not only to avoid the internal resonance by thecavity 48, but also to convert acoustic wave energy into thermal energy by internal friction of theporous material 49, and thus the noise reduction effect can be further enhanced. Theporous material 49 may be anything as long as it has an oil resistance property and a refrigerant resistance property, but extremely high noise reduction effect can be obtained by adopting a demister or glass wool. The demister in this case means the one which is given the function as a porous material by arranging a plurality of metal wires in a meshed form. -
FIG. 3 is a noise spectrum diagram for explaining the effect of the present invention. When there is no cavity in theslide valve 23, the length in the axial direction of the space formed as thegas passages cavity 48 is provided in theslide valve 23, the space formed as thegas passages - The noise data shown in
FIG. 3 is only one example. The peak which can be decreased by applying the present invention depends on the length in the axial direction of the discharge space and on the wavelength of the meshing frequency, and thus the fifth order component (5 f) does not always become the dominant peak. According to the present invention, whatever order component constitutes the dominant peak, it is possible to extend the length in the axial direction of the discharge space by forming thecavity 48 in theslide valve 23, so as not to correspond to the wavelength of the frequency component at which the resonance occurs, which can reduce noise. - It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims.
Claims (8)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2005-190879 | 2005-06-30 | ||
JP2005190879A JP4265577B2 (en) | 2005-06-30 | 2005-06-30 | Two stage screw compressor |
Publications (1)
Publication Number | Publication Date |
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US20070003421A1 true US20070003421A1 (en) | 2007-01-04 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US11/442,354 Abandoned US20070003421A1 (en) | 2005-06-30 | 2006-05-30 | Two-stage screw compressor |
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US (1) | US20070003421A1 (en) |
JP (1) | JP4265577B2 (en) |
CN (1) | CN100455814C (en) |
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CN110388320A (en) * | 2019-08-26 | 2019-10-29 | 珠海格力电器股份有限公司 | Two-stage screw compressor and air-conditioner set with balancing axial thrust function |
CN112431759A (en) * | 2020-11-26 | 2021-03-02 | 珠海格力电器股份有限公司 | Compressor with high adjustment precision, control method thereof and air conditioning system |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3687224A (en) * | 1970-02-10 | 1972-08-29 | Svenska Rotor Maskiner Ab | Mufflers |
US4062199A (en) * | 1975-06-24 | 1977-12-13 | Kabushiki Kaisha Maekawa Seisakusho | Refrigerating apparatus |
US4842501A (en) * | 1982-04-30 | 1989-06-27 | Sullair Technology Ab | Device for controlling the internal compression in a screw compressor |
US5173021A (en) * | 1990-07-26 | 1992-12-22 | Garrett Automotive Limited | Compressors |
US6409490B1 (en) * | 2001-05-25 | 2002-06-25 | York International Corporation | Rotary screw compressor with slide valve and slide stop guidance bushings |
US6881040B2 (en) * | 2001-02-15 | 2005-04-19 | Mayekawa Mfg. Co., Ltd. | Multi-stage screw compressor unit accommodating high suction pressure and pressure fluctuations and method of operation thereof |
US20080131301A1 (en) * | 2005-02-07 | 2008-06-05 | Carrier Corporation | Screw Compressor Lubrication |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0759951B2 (en) * | 1989-03-20 | 1995-06-28 | ダイキン工業株式会社 | Capacity control device for screw type two-stage compressor |
JPH03185293A (en) * | 1989-12-15 | 1991-08-13 | Hitachi Ltd | Displacement compressor rotating screw |
JP3431813B2 (en) * | 1997-11-26 | 2003-07-28 | 株式会社神戸製鋼所 | Two-stage screw compressor |
JP3837298B2 (en) * | 2001-03-07 | 2006-10-25 | 株式会社神戸製鋼所 | Screw refrigerator |
JP4403739B2 (en) * | 2003-07-11 | 2010-01-27 | ダイキン工業株式会社 | Screw compressor |
-
2005
- 2005-06-30 JP JP2005190879A patent/JP4265577B2/en not_active Expired - Fee Related
-
2006
- 2006-05-30 US US11/442,354 patent/US20070003421A1/en not_active Abandoned
- 2006-05-31 CN CNB200610087724XA patent/CN100455814C/en not_active Expired - Fee Related
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3687224A (en) * | 1970-02-10 | 1972-08-29 | Svenska Rotor Maskiner Ab | Mufflers |
US4062199A (en) * | 1975-06-24 | 1977-12-13 | Kabushiki Kaisha Maekawa Seisakusho | Refrigerating apparatus |
US4842501A (en) * | 1982-04-30 | 1989-06-27 | Sullair Technology Ab | Device for controlling the internal compression in a screw compressor |
US5173021A (en) * | 1990-07-26 | 1992-12-22 | Garrett Automotive Limited | Compressors |
US6881040B2 (en) * | 2001-02-15 | 2005-04-19 | Mayekawa Mfg. Co., Ltd. | Multi-stage screw compressor unit accommodating high suction pressure and pressure fluctuations and method of operation thereof |
US6409490B1 (en) * | 2001-05-25 | 2002-06-25 | York International Corporation | Rotary screw compressor with slide valve and slide stop guidance bushings |
US20080131301A1 (en) * | 2005-02-07 | 2008-06-05 | Carrier Corporation | Screw Compressor Lubrication |
Cited By (9)
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EP2209968A4 (en) * | 2007-10-10 | 2014-02-19 | Carrier Corp | Slide valve system for a screw compressor |
WO2010006663A1 (en) * | 2008-07-18 | 2010-01-21 | Ralf Steffens | Cooling for a screw pump |
WO2010041120A2 (en) * | 2008-10-07 | 2010-04-15 | Eaton Corporation | High efficiency supercharger outlet |
WO2010041120A3 (en) * | 2008-10-07 | 2010-12-09 | Eaton Corporation | High efficiency supercharger outlet |
CN102192150A (en) * | 2010-03-02 | 2011-09-21 | 三菱电机株式会社 | Two-stage compressor and heat pump device |
CN109667760A (en) * | 2017-10-17 | 2019-04-23 | 复盛股份有限公司 | Compressor |
CN108167186A (en) * | 2018-03-05 | 2018-06-15 | 珠海格力电器股份有限公司 | Helical-lobe compressor and air-conditioner set |
EP3623629A1 (en) * | 2018-09-12 | 2020-03-18 | Fu Sheng Industrial Co., Ltd. | Fluid machine |
US11255327B2 (en) | 2018-09-12 | 2022-02-22 | Fu Sheng Industrial Co., Ltd | Two-stage screw rotor machine with slide valves |
Also Published As
Publication number | Publication date |
---|---|
JP2007009786A (en) | 2007-01-18 |
CN100455814C (en) | 2009-01-28 |
JP4265577B2 (en) | 2009-05-20 |
CN1892039A (en) | 2007-01-10 |
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