WO2000055506A1 - Compresseur centrifuge bi-etage - Google Patents

Compresseur centrifuge bi-etage Download PDF

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Publication number
WO2000055506A1
WO2000055506A1 PCT/KR2000/000209 KR0000209W WO0055506A1 WO 2000055506 A1 WO2000055506 A1 WO 2000055506A1 KR 0000209 W KR0000209 W KR 0000209W WO 0055506 A1 WO0055506 A1 WO 0055506A1
Authority
WO
WIPO (PCT)
Prior art keywords
compression
external housing
refrigerant
stage centrifugal
compressor
Prior art date
Application number
PCT/KR2000/000209
Other languages
English (en)
Korean (ko)
Inventor
Un Jong Seo
Original Assignee
Samjin Co., Ltd.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Samjin Co., Ltd. filed Critical Samjin Co., Ltd.
Priority to JP2000605105A priority Critical patent/JP2002539377A/ja
Priority to AU34602/00A priority patent/AU3460200A/en
Priority to US09/700,362 priority patent/US6375438B1/en
Publication of WO2000055506A1 publication Critical patent/WO2000055506A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/05—Shafts or bearings, or assemblies thereof, specially adapted for elastic fluid pumps
    • F04D29/056—Bearings
    • F04D29/057—Bearings hydrostatic; hydrodynamic
    • 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
    • F04C11/00—Combinations of two or more machines or pumps, each being of rotary-piston or oscillating-piston type; Pumping installations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D17/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
    • F04D17/08—Centrifugal pumps
    • F04D17/10—Centrifugal pumps for compressing or evacuating
    • F04D17/12—Multi-stage pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D25/00—Pumping installations or systems
    • F04D25/02—Units comprising pumps and their driving means
    • F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
    • F04D25/0606—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/05—Shafts or bearings, or assemblies thereof, specially adapted for elastic fluid pumps
    • F04D29/051—Axial thrust balancing
    • F04D29/0513—Axial thrust balancing hydrostatic; hydrodynamic thrust bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/58—Cooling; Heating; Diminishing heat transfer
    • F04D29/5806—Cooling the drive system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/58—Cooling; Heating; Diminishing heat transfer
    • F04D29/582—Cooling; Heating; Diminishing heat transfer specially adapted for elastic fluid pumps
    • F04D29/584—Cooling; Heating; Diminishing heat transfer specially adapted for elastic fluid pumps cooling or heating the machine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C37/00—Cooling of bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00—Compressor arrangements
    • F25B31/006—Cooling of compressor or motor

Definitions

  • the present invention relates, in general, to a two-stage centrifugal compressor used in refrigeration cycles and, more particularly, to an improvement in such a compressor to allow the electric motor to be cooled by refrigerant of a refrigeration cycle without having another external motor cooler, thus simplifying the refrigerant line of the refrigeration cycle thereby resulting in an improvement in both the operational performance and operational efficiency of the cycle.
  • two-stage centrifugal compressors have been typically used in large-scaled refrigeration systems. However, it is necessary in recent days to actively study such a type of compressors to reduce the size of them since it is desired to use them with indoor air conditioners for houses or automobiles.
  • Conventional two-stage centrifugal compressors for refrigeration systems are composed of an electric motor set at the central portion within a motor housing, with the motor consisting of a rotor and a stator.
  • An impeller having a plurality of blades is set on both ends of a rotating shaft of said rotor.
  • First and second compression parts are provided to the opposite ends of the motor housing.
  • refrigerant circulates through a main refrigerant line of the system and is compressed at the first and the second compression parts by said impellers of the compressor.
  • the compressed refrigerant from the compression parts passes through the main refrigerant line while absorbing heat from the electric motor and cooling the motor.
  • the two-stage centrifugal compressor receives refrigerant from an evaporator and primarily compresses the refrigerant at the first compression part, and secondarily compresses the primarily compressed refrigerant at the second compression part, and so the refrigerant becomes highly heated and highly pressurized gas refrigerant.
  • the gas refrigerant having high temperature and high pressure is fed from the compressor to a condenser.
  • gas refrigerant is sucked from an evaporator into the compressor C through a first refrigerant line L ⁇
  • the refrigerant is primarily compressed at the first compression part C,.
  • the refrigerant is, thereafter, fed into the second compression part C 2 of the compressor C through an external refrigerant line L 2 so as to be secondarily compressed at that compression part C 2 , and so the refrigerant becomes highly heated and highly pressurized gas refrigerant.
  • the gas refrigerant having a high temperature and a high pressure, is fed from the compressor C into a condenser.
  • a motor cooling cycle is separately provided in the fixed jacket Mj of the electric motor M.
  • refrigerant from the compressor C circulates through another refrigerant line L 3 under the control of a separate cooling unit Cu, thus cooling the motor M.
  • Fig. lb shows a refrigerant cycle diagram of a conventional two-stage centrifugal compressor according to another embodiment of the prior art.
  • gas refrigerant is sucked from an evaporator into the compressor C through a first refrigerant line L,.
  • the refrigerant is thus primarily compressed at the first compression part C, of the compressor C and is secondarily compressed at the second compression part C 2 prior to being fed into a condenser in the same manner as that described for the embodiment of Fig. la.
  • the condenser condenses the refrigerant so as to convert the phase of the refrigerant from a gas phase into a liquid phase prior to feeding the refrigerant to an evaporator.
  • this compressor C a part of the condensed refrigerant is sucked into and flows in the fixed jacket M j of the electric motor M.
  • the liquid refrigerant is evaporated while flowing in the jacket M j and is joined to an external refrigerant line L 4 prior to being sucked into the second compression part C 2 of the compressor C.
  • the gas refrigerant from the jacket M j is compressed to become a highly pressurized refrigerant.
  • Fig. lc shows a refrigerant cycle diagram of a conventional two-stage centrifugal compressor according to a further embodiment of the prior art.
  • gas refrigerant is sucked from an evaporator into the compressor C through a first refrigerant line L, and flows in the interior of the compressor C while cooling the electric motor M.
  • the refrigerant is, thereafter, sucked into the first compression part C j of the compressor C through an external refrigerant line L 2 , thus being primarily compressed at that compression part C
  • the refrigerant is sucked from the first compression part C, into the second compression part C 2 of the compressor C through the external refrigerant line L 2 , thus being secondarily compressed at that compression part C 2 prior to being fed into a condenser.
  • Fig. Id shows a refrigerant cycle diagram of a conventional two-stage centrifugal compressor according to still another embodiment of the prior art.
  • gas refrigerant is sucked from an evaporator into the compressor C through a first refrigerant line L l5 and is primarily compressed at the first compression part C, of the compressor C.
  • the refrigerant is, thereafter, fed
  • an additional refrigerant line L 4 extends through the fixed jacket M j of the electric motor M prior to being joined to the external refrigerant line L 2 .
  • the condensed liquid refrigerant from the condenser flows through the refrigerant line L 4 .
  • Fig. le shows a refrigerant cycle diagram of a conventional two-stage centrifugal compressor according to still another embodiment of the prior art. In the embodiment of Fig. le, gas refrigerant is sucked from an evaporator into the first compression part C, of the compressor C through a first refrigerant line L,, and is primarily compressed at that compression part C,.
  • the refrigerant thereafter, flows through an external refrigerant line L 2 so as to pass through the interior of the compressor C while cooling the electric motor.
  • the refrigerant is, thereafter, fed into the second compression part C 2 of the compressor C through the external refrigerant line L 2 , thus being secondarily compressed at that compression part C 2 .
  • gas refrigerant which is separated from liquid refrigerant at a vapor liquid separator of a refrigeration cycle, flows into the second compression part C 2 of the compressor C through an additional refrigerant line L 5 , thus being secondarily compressed at that compression part C 2 .
  • the secondarily compressed refrigerant is discharged from the compressor C into a condenser of the refrigeration cycle.
  • FIG. 1 shows a refrigerant cycle diagram of a conventional two-stage centrifugal compressor according to still another embodiment of the prior art.
  • gas refrigerant is sucked from an evaporator into the first compression part C, of the compressor C through a first refrigerant line L l5 and is primarily compressed at that compression part .
  • the refrigerant thereafter, flows into the second compression part C 2 of the compressor C through both the interior of the compressor C and an external refrigerant line L 2 , thus being secondarily compressed at that compression part C 2 .
  • gas refrigerant which is separated from liquid refrigerant at a vapor liquid separator of a refrigeration cycle, flows into the second compression part C 2 of the compressor C through another refrigerant line L 5 , thus being secondarily compressed at that compression part C 2 .
  • the secondarily compressed refrigerant is, thereafter, discharged from the compressor C into a condenser of the refrigeration cycle.
  • the above-mentioned conventional two-stage centrifugal compressors for refrigeration system have disadvantages as follows. That is, such a compressor C necessarily has a complicated refrigerant passage structure, which allows gas refrigerant to be primarily compressed in the interior of the compressor or at the first compression part C, of the compressor C and to be fed into the second compression part C 2 of the compressor C through an external refrigerant line L 2 so as to be secondarily compressed at that compression part C 2 .
  • Such a refrigerant passage structure forces the compressor C to have additional refrigerant lines L 3 - L 5 in addition to the main refrigerant line L,, which is necessarily provided at the compressor C for sucking, compressing and discharging the refrigerant.
  • the refrigerant passage structure of such conventional two-stage centrifugal compressors is undesirably complicated since it consists of a plurality of refrigerant lines L, - L 5 .
  • Such a complicated refrigerant passage structure also disturbs flowing of refrigerant, thus causing a refrigerant pressure loss. As a result, this finally deteriorates the operational performance of such compressors in addition to a reduction in both work efficiency and productivity while producing such compressors.
  • an object of the present invention is to provide a two-stage centrifugal compressor, which is designed to primarily compress gas refrigerant at a first compression chamber, or the first compression part, of the compressor and to allow the primarily compressed refrigerant to pass through the interior space of an external housing so as to reach a second compression chamber provided at the upper end of the external housing, and to secondarily compress the refrigerant at the second compression chamber, and which thus has a simplified refrigerant passage structure and effectively cools the electric motor and the bearing parts for the refrigeration cycle without having another external cooling unit and reduces a consumption of electric power, and improves the operational performance and operational efficiency of a refrigeration system.
  • the present invention provides a two-stage centrifugal compressor, comprising an electric motor positioned at the central portion within an external housing, the motor being composed of a fixed jacket including a stator provided with a coil, and a rotor having a rotor core provided on a rotating shaft at a position opposite to the stator, and rotatably supported by radial gas bearings and thrust gas bearings at upper and lower ends of the rotating shaft, and first and second compression parts provided at the upper and lower ends of the external housing of the motor and respectively having an impeller, further comprising: a plurality of internal fluid passages regularly formed on the internal surface of each of the upper and lower end portions of the external housing so as to allow the first and second compression parts to communicate with each other through the interior space of the external housing; and upper and lower bearing housings fixedly mounted to the upper and lower ends of the external housing, with a plurality of fluid openings being regularly formed on the upper and lower bearing housings and communicating with both compression chambers of the first and second compression parts,
  • the second compression part has the second compression chamber within a compressing casing, receiving an inlet part of a diffuser and surrounding outer part thereof, provided with a refrigerant discharging port, and has an internal cover with a fluid passage communicating with the fluid openings of the upper and lower bearing housings.
  • Figs, la to If are refrigerant flow cycle diagrams of conventional two- stage centrifugal compressors;
  • Fig. 2 is a sectional view, showing the construction of a two-stage centrifugal compressor in accordance with the preferred embodiment of the present invention;
  • Fig. 3 is a perspective view of a fixed jacket of the two-stage centrifugal compressor of this invention
  • Fig. 4 is an exploded perspective view of upper and lower radial gas bearings included in the compressor of this invention
  • Fig. 5a is an exploded perspective view, showing the construction of both the lower end portion of an external housing and the lower bearing housing of the compressor of this invention
  • Fig. 5b is a bottom view, showing both the lower end portion of the external housing and the lower bearing housing of the two-stage centrifugal compressor of Fig. 5a when the parts of Fig. 5b are assembled together;
  • Fig. 5c is a partially sectioned exploded perspective view of a second compression part of the compressor of this invention, with both the sealing housing and the diffuser being removed from the compression part; and Fig. 6 is an exploded perspective view of a movable bearing part of the compressor of this invention.
  • Figs. 2 to 6 are views shows the construction of a two-stage centrifugal compressor in accordance with the preferred embodiment of this invention.
  • the two-stage centrifugal compressor of this invention comprises an electric motor 10, which is set at the central portion within the interior of an external housing 13 and generates a rotating force.
  • Upper and lower bearing parts are provided at the upper and lower ends of the external housing 13 and are supported by dynamic gas bearings, thus allowing the rotor 11 to be rotatable at a high speed.
  • the compressor also has first and second compression parts provided at the lower and upper ends of the external housing 13 and primarily and secondarily compress gas refrigerant.
  • the electric motor 10 comprises the rotor 11 and a stator 12.
  • the rotor 11 is composed of lower and upper impellers 35 of the first and second compression parts, with the two impellers 35 being set on the lower and upper ends of a rotating shaft 111.
  • the stator 12, used for electromagnetically rotating the rotor 11, is interiorly provided with a fixed stator core 124 having a coil 121 and is externally covered with a fixed jacket 122. This stator 12 is fitted into the external housing 13.
  • a plurality of external fluid passages 123 are regularly formed on the external surface of the fixed jacket 122 of the stator 12 and allow refrigerant to flow along the internal surface of the external housing 13.
  • external fluid passages 123 may be regularly formed on the internal surface of the external housing 13 in place of the fixed jacket 122 of the stator 12 without affecting the functioning of this invention.
  • the rotor 11 of the motor 10 has a rotor core 112 that is formed on the rotating shaft 111 at a position opposite to the stator 12.
  • a collar 113 is integrally formed on the lower end portion of the rotating shaft 111 and is supported by a movable bearing unit including a thrust gas bearing 23.
  • the external housing 13 is a cylindrical body, which totally covers the motor 10 and is open at the first and second compression parts.
  • a plurality of internal fluid passages 14 are regularly formed on the internal surface of each of the upper and lower end portions of the housing 13.
  • the upper and lower bearing parts are fabricated as follows. That is, the upper and lower ends of the rotating shaft 111 are rotatably supported by radial gas bearings 22 within the upper and lower bearing housings.21a and 21b set in the upper and lower ends of the external housing 13.
  • the thrust gas bearing 23 is fixed to the lower bearing part using a plurality of locking bolts 23 e while rotatably covering the collar 113 of the rotating shaft 111.
  • Both the radial gas bearings 22 and the thrust gas bearing 23 are designed to allow the rotating shaft 111 to be rotatable without being mechanically frictioned.
  • the construction of the upper and lower bearing parts, rotatably supporting the upper and lower ends of the rotating shaft 111 relative to the external housing 13, is shown in detail in Figs.
  • the bearing housings 21a and 21b of the upper and lower bearing parts are mounted to the upper and lower ends of the external housing 13 using a plurality of locking bolts 25a.
  • three screw holes 211 are regularly and radially formed on the external surface of a fitting part while being spaced out at an angle of 120°.
  • the bearing housings 21a and 21b are fitted into the upper and lower ends of the cylindrical external housing 13.
  • Three set screws 212 are tightened into the screw holes 211 of each of the two bearing housings 21a and 21b and hold three arcuate pieces 221 forming a radial gas bearing 22 within each of the two bearing housings 21a and 21b.
  • a plurality of arcuate fluid openings 213 are regularly formed on each of the two bearing housings 21a and 21b.
  • the above fluid openings 213 communicate with the internal fluid passages 14 of the external housing 13 when the two bearing housings 21a and 21b are fitted into the upper and lower ends of the external housing 13.
  • Both a sealing housing 26 and a diffuser 27 are fixedly mounted to each of the two bearing housings 21a and 21b using a plurality of locking bolts 25b, thus forming the first compression chamber 31 at the lower end portion of the housing 13 and the second compression chamber 32 at the upper end portion of the housing 13.
  • Each of the radial gas bearings 22 is composed of three arcuate pieces 221 having a radius of curvature of 120°.
  • the three pieces 221 form a cylindrical radial gas bearing 22, each has a semicircular hole 222 on its external surface at a position around the central portion.
  • the three arcuate pieces 221 are regularly arranged to cover the rotating shaft 111, with three set screws 212 passing through the screw holes 211 of each bearing housing 21a, 21b prior to being set in the semicircular holes 222 of the three arcuate pieces 221 at their ends.
  • Fig. 6 shows the construction of both the thrust gas bearing 23, used for supporting the collar 113 of the rotating shaft 111, and the movable bearing unit receiving the thrust gas bearing 23.
  • the above movable bearing unit comprises the thrust bearing 23, which supports the collar 113 of the rotating shaft 111 at a position above the top end of the lower bearing housing 21b.
  • the movable bearing unit also comprises an external ring 24, which receives the thrust gas bearing 23 and rotatably holds the bearing 23 while being freely movable within a predetermined moving range.
  • the thrust gas bearing 23 is comprises a space ring 23 a that is fitted over the collar 113 of the rotating shaft 111.
  • the space ring 23a and the gas bearings 23c and 23d are fixed to a fixing ring 23b using a plurality of locking bolts 23e.
  • the upper and lower gas bearings 23 c and 23 d are arranged on the upper and lower surfaces of the space ring 23 a and are respectively provided with a central opening 231 for receiving the rotating shaft 111.
  • a plurality of radial linear grooves 232 are regularly formed on a surface of each gas bearing 23d, at which the bearing 23d is brought into contact with the collar 113 of the rotating shaft 111.
  • a plurality of sectorial wide and shallow depressions 233 are regularly formed on the collar contact surface of gas bearing 23 d while communicating with the radial linear grooves 232. Such a depression 233 forms a gas film in the rotating direction of the rotating shaft 111.
  • the upper gas bearing 23c is composed of two semicircular parts, and so it is possible to improve work efficiency while assembling the parts of the movable bearing unit.
  • the central portion of the upper gas bearing 23 c around the central opening is bossed upwardly to a height leveled with the height of the fixing ring 23b, thus forming an annular boss 235, with the edge of the upper gas bearing 23c being left thin.
  • a plurality of bolt holes 236 are regularly formed along the edge of each of the upper and lower gas bearings 23c and 23d and the space ring 23a in a way such that the holes 236 of the space ring 23 a and the bearings 23 c and 23 d are formed at corresponding positions of same radius.
  • the upper and lower gas bearings 23 c and 23 d and the space ring 23 a are locked to the collar 113 of the rotating shaft 111 using the locking bolts 23e passing through the bolt holes 236.
  • Regularly formed along the edge of the fixing ring 23b are a plurality of bolt holes 237.
  • These bolt holes 237 are formed at positions corresponding to the bolt holes 236 of both the space ring 23a and the upper and lower gas bearings 23c and 23d, and allow the fixing ring 23b to be assembled with the space ring 23a and the upper and lower gas bearings 23c and 23d using the locking bolts 23e.
  • the external ring 24 has two radial hinge holes 24a at diametrically opposite positions, and so the ring 24 is rotatably held by the two set screws 24b set on the external housing 13.
  • Two radial screw holes 24c are formed on the external ring 24 at positions angularly spaced from the radial hinge holes 24a at an interval of 90°, with two set screws 24d being tightened to the two screw holes 24c of the ring 24 and being set in the hinge holes 238 of the space ring 23 a, thus rotatably holding the thrust gas bearing 23.
  • the above thrust gas bearing 23 is assembled as follows. That is, the space ring 23 a is primarily laid on the lower gas bearing 23 d. Thereafter, the rotating shaft 111 is fitted into the central opening 231 of the lower gas bearing 23 d downwardly until the lower surface of the collar 113 of the shaft 111 comes into contact with the top surface of the lower gas bearing 23 d. The space ring 23 a is, thereafter, fitted over the collar 113 of the rotating shaft 111 prior to laying both the upper gas bearing 23c and the fixing ring 23b on the top surfaces of both the space ring 23a and the collar 113. The fixing ring 24b, the upper gas bearing 23c, the space ring 23a and the lower gas bearing 23d are assembled to each other into a single body using a plurality of locking bolts 23 e passing through the bolt holes 236 and 237 downwardly.
  • the upper and lower bearing housings 21a and 21b are mounted to the upper and lower ends of the external housing 13, with both a sealing housing 26 and a diffuser 27 fixedly mounted to each of the two bearing housings 21a and 21b so as to form the desired compression parts.
  • An impeller 35 having a plurality of blades, is set on each end of the rotating shaft 111 of the rotor 11, passing through each sealing housing 26, at a position between the sealing housing 26 and the diffuser 27.
  • Two compression casings 33 and 34 are mounted to the outside of the diffusers 27 and the two bearing housings 21a and 21b using a plurality of locking bolts 25c, thus forming the first and second compression chambers 31 and 32.
  • a refrigerant suction port 331 is formed at the central portion of the lower compression casing 33 and sucks refrigerant into the first compression chamber 31 due to a suction force generated by a rotation of the lower impeller 35.
  • the impeller 35 is positioned to face an associated diffuser 27, thus sucking refrigerant through the inlet of the diffuser 27.
  • a refrigerant discharging port 341 is formed on the upper compression casing 34 of the second compression part and discharges high temperature and high pressure gas refrigerant into a condenser (not shown) of the refrigeration system.
  • a flash pipe 342 is connected to the central portion of the compression casing 34, and so gas refrigerant, separated from liquid refrigerant at a gas liquid separator (not shown), is sucked into the upper compression part.
  • the upper compression casing 34 is provided with an internal cover 36, which guides the refrigerant sucked from the interior space of the external housing 13.
  • the internal cover 36 of the upper compression casing 34 also has a compression space for compressing the refrigerant. Therefore, the second compression chamber 32 is formed in the upper compression casing 34 while receiving the inlet part of a diffuser 27 and covering the diffuser 27, with a refrigerant discharging port 361 being formed at the second compression chamber
  • a fluid passage 362 is formed in the outside part of the internal cover 36 of the upper compression casing 34 and communicates with the arcuate fluid openings 213 of the upper bearing housing 21a.
  • the above two-stage centrifugal compressor of this invention is operated as follows.
  • the rotating shaft 111 of the rotor 11 is electromagnetically rotated.
  • the arcuate pieces 221 of the radial gas bearings 22, provided within the upper and lower bearing housings 21a and 21b and supporting both ends of the shaft 111 are rocked along with the shaft 111 since the pieces 221 are somewhat eccentrically supported by the set screws 212.
  • the arcuate pieces 221 are not rocked, but are stopped, and so the pieces 221 smoothly support the shaft 111 while being almost free from coming into frictional contact with the external surface of the shaft 111.
  • the lower surface of the collar 113 of the shaft 111 primarily comes into contact with the top surface of the lower gas bearing 23d as shown in Fig. 6.
  • the gas refrigerant, flowing in the interior of the motor 10 is sucked into the sectorial depressions 233 through the radial linear grooves 232 of the gas bearing 23d, thus forming a gas film. Therefore, the collar 113 of the rotating shaft 111 is smoothly rotated while being suspended in the gap between the upper and lower gas bearings 23 c and 23 d and being almost free from frictional contact.
  • the rotating shaft 111 of the rotor 11 is almost completely free from being undesirably biased downwardly due to a difference of pressure between primarily compressed refrigerant of the first compression chamber 31 and secondarily compressed refrigerant in the second compression chamber 32 or due to weight of the rotor 11.
  • the shaft 111 is also prevented from being undesirably biased to a side or from being undesirably vibrated in the initial stage of the operation of the motor 10.
  • Due to the radial and thrust gas bearings 22 and 23, the two-stage centrifugal compressor of this invention is free from a mechanical problem at a portion around the rotating shaft 111 of the motor 10, and so it is possible to improve the operational reliability of the compressor.
  • the compressor of this invention is smoothly operated without being troubled in a variety of operational modes from a low speed operational mode of about 3,500 rpm to a super high speed operational mode of about 60,000 rpm.
  • the primarily compressed gas refrigerant is introduced from the first compression chamber 31, provided at the lower portion of the external housing 13, into the interior of the housing 13 through both the arcuate fluid openings 213 and the internal fluid passages 14.
  • the gas refrigerant desirably absorbs heat from the coil 121 of the stator 12 and cools the stator 12 while passing through the gap between the stator 12 and the rotor core 112 of the rotor 11 and through the external fluid passages 123 formed on the external surface of the fixing jacket 122 covering the stator 12.
  • the gas refrigerant in the interior of the external housing 13 is also sucked into the radial gas bearings 22 of the upper and lower bearing housings 21a and 21b, and is partially sucked from the upper and lower surfaces of the collar 113 of the rotating shaft 111 into both the radial grooves 232 and the sectorial depressions
  • the gas refrigerant thus desirably absorbs heat from the upper and lower bearing parts and absorbs heat from the thrust gas bearing 23, thereby effectively cooling them.
  • the primarily compressed gas refrigerant of the first compression chamber 31 is introduced into the external housing 13 through both the arcuate fluid openings 213 of the lower bearing housing 21b and the internal fluid passages 14 of the housing 13, and cools the upper and lower bearing parts in addition to the motor 10 while passing through them. It is thus possible to prevent the motor 10 from being overheated and to allow the motor 10 to be always optimally operated during an operation of the compressor.
  • the two impellers 35 provided at upper and lower ends of the shaft 111, are rotated at a high speed along with the shaft 111.
  • Gas refrigerant is thus sucked into the lower compression casing 33 through the refrigerant suction port 331 of the casing 33 due to a suction force of the lower impeller 35 and is introduced into the first compression chamber 31 through both the lower impeller 35 and the lower diffuser 27.
  • the gas refrigerant is primarily compressed within the first compression chamber 31.
  • the primarily compressed gas refrigerant is discharged from the compression chamber 31 into the external housing 13 through both the arcuate fluid openings 213 of the lower bearing housing 21b and the internal fluid passages 14 of the housing 13.
  • the primarily compressed gas refrigerant passes through the upper and lower bearing parts in addition to the motor 10 prior to flowing into the upper compression casing 34 of the second compression part.
  • the primarily compressed gas refrigerant passes through the internal fluid passages 14 of the housing 13, the arcuate fluid openings 213 of the upper bearing housing 21a and the fluid passage 362 of the internal cover 36 prior to reaching the upper compression casing 34.
  • the gas refrigerant flows into the second compression chamber 32 of the internal cover 36 after passing through the compression casing 34, the inlet port of the diffuser 27 and the impeller 35.
  • the primarily compressed gas refrigerant is thus secondarily compressed within the second compression chamber 32 due to the suction force generated by the rotation of the upper impeller 35.
  • the secondarily compressed gas refrigerant is, thereafter, discharged from the compression chamber 32 into a condenser (not shown) of the refrigeration cycle through the refrigerant discharging port 341 of the upper compression casing 34.
  • the present invention provides a two-stage centrifugal compressor.
  • the compressor of this invention is designed to primarily compress gas refrigerant at a first compression chamber, or the first compression part, provided at the lower end of the compressor.
  • This compressor also allows the primarily compressed refrigerant to pass through the interior space of an external housing so as to reach a second compression chamber provided at the upper end of the external housing.
  • the primarily compressed refrigerant is secondarily compressed at the second compression chamber prior to being discharged into a condenser of a refrigeration cycle.
  • the two-stage centrifugal compressor of this invention thus has a simplified refrigerant passage structure and effectively cools its electric motor in addition to upper and lower bearing parts using an existing refrigeration cycle without having another external cooling unit different from conventional two-stage centrifugal compressors. Therefore, this compressor reduces a consumption of electric power, and improves the operational performance and operational efficiency of a refrigeration system.
  • the present invention is preferably adapted to refrigerant compressors for refrigeration systems, and is preferably used with refrigerators or air conditioners.

Abstract

Cette invention concerne un compresseur centrifuge bi-étagé dont la structure simplifiée pour le passage du réfrigérant assure un refroidissement efficace non seulement de son moteur électrique, mais aussi de ses paliers grâce au seul cycle de refroidissement existant, sans recours à un organe de refroidissement externe. Il en résulte une moindre consommation d'énergie électrique ainsi que de meilleures caractéristiques de marche et une plus grande efficacité du refroidissement. Sur le compresseur centrifuge bi-étagé selon l'invention, les parties haute et basse d'un carter extérieur (13) présentent sur leur surface intérieure une pluralité de passages internes pour liquide (14), régulièrement disposés, de sorte que le premier et le second étage de compression communiquent entre eux via l'espace intérieur du carter extérieur (13). Les logements de palier (21a) et (21b) sont montés fixe sur les extrémités supérieure et inférieure du carter extérieur (13). Ces logements (21a) et (21b) présentent une pluralité d'ouvertures (213), disposées régulièrement, qui communiquent avec les deux chambres de compression (31) et (32) du premier et du second étage de compression et qui correspondent aux passages internes (14) pour liquide du carter extérieur (13d). Au niveau du second étage de compression, la chambre de compression (32) est logée dans une gaine de compression (34) qui reçoit la partie admission d'un diffuseur (27), entoure la partie extérieure de ce dernier, et comporte un orifice de décharge de réfrigérant (361). Elle comporte également un couvercle interne (36) avec un passage pour liquide (362) qui communique avec les ouvertures pour liquide (213) des logements de palier supérieur et inférieur (21a) et (21b).
PCT/KR2000/000209 1999-03-15 2000-03-15 Compresseur centrifuge bi-etage WO2000055506A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2000605105A JP2002539377A (ja) 1999-03-15 2000-03-15 二段遠心圧縮機
AU34602/00A AU3460200A (en) 1999-03-15 2000-03-15 Two-stage centrifugal compressor
US09/700,362 US6375438B1 (en) 1999-03-15 2000-06-15 Two-stage centrifugal compressor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR1019990008664A KR100288315B1 (ko) 1999-03-15 1999-03-15 2단 원심압축기
KR1999/8664 1999-03-15

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WO2000055506A1 true WO2000055506A1 (fr) 2000-09-21

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US (1) US6375438B1 (fr)
JP (1) JP2002539377A (fr)
KR (1) KR100288315B1 (fr)
CN (1) CN1115490C (fr)
AU (1) AU3460200A (fr)
WO (1) WO2000055506A1 (fr)

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CN105765319A (zh) * 2013-11-14 2016-07-13 丹佛斯公司 具有扩展范围和容量控制特征的两级离心式压缩机

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CN1115490C (zh) 2003-07-23
AU3460200A (en) 2000-10-04
CN1296551A (zh) 2001-05-23
US6375438B1 (en) 2002-04-23
JP2002539377A (ja) 2002-11-19
KR100288315B1 (ko) 2001-04-16

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