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WO1997016648A1 - Ameliorations apportees a des compresseurs a une seule vis - Google Patents

Ameliorations apportees a des compresseurs a une seule vis Download PDF

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Publication number
WO1997016648A1
WO1997016648A1 PCT/GB1996/002678 GB9602678W WO9716648A1 WO 1997016648 A1 WO1997016648 A1 WO 1997016648A1 GB 9602678 W GB9602678 W GB 9602678W WO 9716648 A1 WO9716648 A1 WO 9716648A1
Authority
WO
WIPO (PCT)
Prior art keywords
chamber
single screw
economiser
pressure
compressor
Prior art date
Application number
PCT/GB1996/002678
Other languages
English (en)
Inventor
Terence William Thomas Young
John Michael Roll
Original Assignee
Aaf-Mcquay Incorporated
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
Priority claimed from GBGB9522516.5A external-priority patent/GB9522516D0/en
Priority claimed from GBGB9522517.3A external-priority patent/GB9522517D0/en
Application filed by Aaf-Mcquay Incorporated filed Critical Aaf-Mcquay Incorporated
Priority to AU73225/96A priority Critical patent/AU7322596A/en
Priority claimed from PCT/GB1996/002677 external-priority patent/WO1997016647A1/fr
Publication of WO1997016648A1 publication Critical patent/WO1997016648A1/fr

Links

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
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/02—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids specially adapted for several pumps connected in series or in parallel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B41/00—Pumping installations or systems specially adapted for elastic fluids
    • F04B41/06—Combinations of two or more pumps
    • 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
    • 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
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/10—Compression machines, plants or systems with non-reversible cycle with multi-stage compression
    • 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
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/07—Details of compressors or related parts
    • F25B2400/075—Details of compressors or related parts with parallel compressors
    • 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
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/13—Economisers
    • 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
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/23—Separators
    • 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
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/026—Compressor control by controlling unloaders

Definitions

  • This invention relates to a single screw compressor having at least two pumping chambers of variable volume formed in the flutes of a screw, each of which receives fluid to be compressed from a primary inlet when the respective pumping chamber has a first volume at least close to its maximum volume and each of which discharges compressed fluid from an outlet when the respective pumping chamber has a second volume which is less than said first volume, one of said pumping chambers having a secondary inlet open to the said one chamber when it has a third volume intermediate the first and second volumes after said one chamber is closed off from its primary inlet but before the said one chamber opens to its outlet.
  • a single screw compressor of the kind specified such a compressor will be referred to as "a single screw compressor of the kind specified" .
  • the invention seeks to improve the efficiency of a single screw compressor (in particular a refrigerator compressor) of the kind specified.
  • a single screw compressor of the kind specified is characterised in that means is provided on the compressor to connect the outlet of the other pumping chamber to the secondary inlet of said one pumping chamber.
  • the invention can be seen as a way of modifying a prior art single screw refrigeration compressor having an economiser port to improve performance without the need for any economiser vessel or system-derived side load.
  • the secondary inlet need not be in a fixed position in the said one pumping chamber and both pumping chambers in a compressor of the kind specified can have such secondary inlets.
  • Means can be provided to utilise conventional oil or liquid refrigerant injection in either or both pumping chambers.
  • a compressor according to this invention may be further refined by employing an economiser facility (e.g. with a conventional economiser vessel or heat exchanger) . Greater performance can be achieved in this way.
  • an economiser facility e.g. with a conventional economiser vessel or heat exchanger
  • Figure 1 shows, schematically, a single-screw refrigeration compressor of the kind specified operating in conventional economiser manner
  • FIG. 2 shows the components of the schematic screw compressor of Figure 1 connected in accordance with the invention without an economiser vessel
  • FIG 3 shows the components of the schematic screw compressor of Figure 1 connected in accordance with the invention but with an economiser vessel connected to one of the pumping chambers,
  • Figure 4 shows the components of the schematic screw compressor of Figure 3 further modified to utilise two economiser vessels connected in series
  • Figures 5 to 8 are graphs showing respectively pressure/enthalpy diagrams for the compressors shown in Figures 1 to 4, Figures 9, 10 and 11 show less schematically a single rotor, twin star wheel compressor, according to the invention, Figure 10 being a section on line X-X of Figure 9 and Figure 11 being a partially dismantled end view, and
  • Figure 12 is a bar chart comparing C.O.P. and duty values of a range of different single screw compressor arrangements.
  • Figures 1 to 4 illustrate piston-in-cylinder 10 pumping chambers for easier understanding of the inventive concept.
  • Figure 1 shows a prior art refrigeration compressor unit having two pumping chambers 10A and 10B each having a primary inlet Ila, lib, a secondary inlet (or economiser port) 12a,
  • FIG. 2 shows how the compressor of Figure 1 is adapted in accordance with the invention.
  • the outlet 13a of chamber 25 10A is now connected to the intermediate inlet 12b of chamber 10B.
  • Both inlets Ila and lib remain connected to a common suction line 14 but only outlet 13b now feeds the delivery port 15.
  • the intermediate port 12a is not used and this is the arrangement shown in Figure 2.
  • Figure 3 shows a further modification with the addition of an economiser vessel 19.
  • the vapour outlet 19a from this economiser vessel is returned to the intermediate port 12a.
  • Figure 4 shows a still further modification with two economiser vessels 19A, 19B connected.
  • the vapour outlet from the first economiser vessel 19A operating at the higher saturation pressure, is returned to the intermediate port 12b, where it mixes with the flow from the discharge port 13a as it enters chamber 10B.
  • the vapour outlet from the second economiser vessel 19B is returned to the intermediate port 12a and flows into chamber 10A.
  • Unloading of the compressors 10A, 10B shown schematically in Figures 2, 3 and 4 can be undertaken in the normal way except that it is anticipated that the compression process in chamber 10A, pumping into the economiser port 12b, would be unloaded before the compression process in chamber 10B.
  • Figure 5 shows the pressure enthalpy diagram for a standard economised single screw compressor machine.
  • compression of a non-economised machine would normally progress along line 1-3, but when economiser flow is introduced at an intermediate pressure Pe then, provided the temperature of this gas from the economiser vessel is lower than the temperature of the gas in the flute of the screw at this point then the temperature within the compressor will fall to point 4, compression will then continue to point 5 to achieve the delivery pressure Pd. Desuperheating and condensing of the gas will then take place as shown by line to 5 to 6.
  • the liquid would pass through an expansion device where the pressure would be reduced to the suction pressure Ps at point 10.
  • Figure 6 shows the pressure enthalpy diagram for a simple single screw compressor in accordance with the invention.
  • the compression process would normally progress along dashed line 1-4.
  • the compression process is divided into two compression chambers such that the first compression chamber compresses over the entire required pressure range from suction pressure to delivery pressure, whereas the second compression chamber compresses over a reduced compression ratio (and thus with higher efficiency and reduced temperature) from suction pressure Ps to the pressure Pe at the economiser port of the first chamber, as shown by line 1- 3.
  • the gas from this second chamber is fed, via the economiser port of the first chamber, into the first chamber, where the two compression gas streams are combined.
  • the compression process in the first chamber progresses along line 1-2, which is less efficient than that achieved in the second chamber due to the gas leakage effects from the higher pressure ultimately achieved in this compression chamber.
  • the combined gas streams will then be further compressed in the first compression chamber to the final delivery pressure Pd at point 5.
  • the cycle continues with desuperheating and condensing taking place between 5 and 6, the pressure then being dropped from 6 to 7 and the liquid boiled off in the evaporator from 7 to 1.
  • the benefits are not shown by an increase in enthalpy change in the evaporator, but rather by an increase in mass flow through the evaporator, together with an improvement in coefficient of performance (C.O.P.), which can not be represented in Figure 6.
  • Figure 7 shows the result of the addition of economising of the low compression ratio chamber.
  • the two gas flows are combined in the first compression chamber from points 2 and 3, like the non-economised arrangement discussed above, and compressed together from pressure Pe to the final delivery pressure Pd at point 5.
  • the second compression chamber combines the economising effect described previously.
  • desuperheating and condensing of the gas takes place between 5 and 6.
  • the liquid is then dropped in pressure to point 7 (pressure Pel) in the economiser vessel, where some liquid is boiled off and returned to the economiser port of the second compression chamber.
  • This evaporation cools the remaining liquid in the economiser to point 8.
  • the remaining liquid in the economiser is fed to the evaporator, where it evaporates, thus providing the required cooling and is ultimately returned at pressure Ps from point
  • FIG. 7 again shows an open-flooded economiser vessel but it is equally possible to accomplish this economiser liquid cooling in an indirect heat exchanger where the liquid that is cooled is retained at the higher condensing pressure.
  • the beneficial effect of economising can be seen by the increase in enthalpy change in the evaporator shown by line 9-1 in this diagram when compared with line 7-1 of Figure 6.
  • Figure 8 shows the performance of a compressor similar to that used for Figure 7, but with the addition of means for providing economising to the first compression chamber.
  • This compressor operates similarly to that previously described (for Figure 7) except that after the gas from the second ' compression chamber has been fed to the first compression chamber, further economising is introduced in one of two possible ways. Either additional high pressure economiser flow is also introduced at the pressure Pe where the two compression chambers are combined, from an additional economiser vessel, or alternatively economiser flow from the second high pressure economiser operating at pressure Pem is introduced at a later stage either by pressure regulation or an additional later economiser port into the first compression chamber. In this instance the beneficial effect of additional economising can be seen by the increase in enthalpy change in the evaporator shown by line 12-1 in this diagram when compared with 9-1 of Figure 7.
  • FIGS 9 to 11 show a single main rotor, twin star wheel screw compressor externally of generally conventional design, but internally adapted in accordance with the invention.
  • FIG 9 shows a plan view of the casing 31 of a single screw compressor in accordance with the invention.
  • a single screw in the casing 31 provides flutes which serve as pumping chambers with star wheels 32 and 33.
  • the flute terminating in a tooth of star wheel 32 on side 1 of the casing 31 serves as the chamber 10B in Figures 2, 3 or 4 and the flute terminating in a tooth of star wheel 33 on side 2 serves as the chamber 10A in those three Figures.
  • Figure 10 is a section on line X-X of Figure 9 and Figure 11 is an end view of the compressor of Figure 9 with the suction end cap removed.
  • the screw is not shown in Figures 9 or 10 but occupies the bore 30 and is driven by the shaft 30a shown in Figure 9.
  • the suction port 34 communicates with the low pressure end of each pumping chamber and in a conventional compressor both chambers will discharge to a common delivery port 35.
  • the suction port 34 remains open to both sides of the compression process but the delivery ports from each side of the compression process are now separated.
  • Side l of the compressor is piped up externally in the conventional fashion with the delivery connected to the condenser. However delivery gas from side 2 of the compressor is taken, either through an internal chamber or via an external pipe, to an economiser port 36 (not shown in Figure 9) provided on side
  • Figure 10 shows the bore 30 for the screw and recesses 37a, 37b to receive the sliding valve gear conventional in a single-screw compressor. It also shows partitions 38a, 38b which separate the delivery ports from the two sides of the compressor, allowing the required separation of the deliveries from the two sides of the compressor.
  • Figure 11 is an end view of the compressor shown in Figure 9 in the direction of the arrow XI, with the delivery end cover 39 removed.
  • One economiser port 36 is shown which is connected by an internal passage 40 to the delivery of side
  • this port can be enlarged compared to the economiser port provided in a conventional machine.
  • the economiser connection of side 2 may be used to provide a conventional economiser facility. Unloading of a single screw compressor modified in this way can be accomplished by unloading the compression processes on both sides together in the normal way. However, for efficient part-load operation the compression process pumping into the economiser port 36 should be unloaded first, followed by unloading of the remaining compression process.
  • the economiser port 36 need not be in a fixed position in the compressor casing, but may be capable of moving within the casing to maintain an optimum part-load economiser position.
  • Main oil injection may be into either both sides or may be into one side only dependent upon cooling and sealing requirements.
  • Liquid injection cooling may be used with injection into either side or the flow from delivery to economiser or any combination of these positions.
  • Extracts from the results of tests conducted are shown in graphical format in the bar chart of Figure 12.
  • Figure 12 shows the increase in performance over and above that secured by a standard single screw compressor connected in the traditional fashion. Both coefficient of performance (C.O.P.) and duty variation are shown.
  • the base line for the graph of Figure 12 (100% performance compared with the standard machine) indicates the actual performance achieved with single screw test compressors connected to operate in the conventional format.
  • the first bar in each section in Figure 12 indicates the initial test result with the compressor modified in accordance with the invention.
  • the second bar in each section indicates the performance achieved when oil injection rates are optimised for a compressor in accordance with the invention.
  • the third bar in each section indicates the effect of adding an economiser system to the unused economiser port of the low pressure compressor.
  • the fourth and fifth bars in each section are a repeat of the tests shown in the second and third bars, but with one of the original compressors replaced by another similar unit. These latter repeat tests were undertaken to ensure that the gains in performance recorded were not peculiar to the actual compressors tested.
  • the pressure of fluid fed to the secondary inlet or economiser port will normally be in the range 30% to 70T of the final discharge pressure from the supercharged compressor.
  • Typical figures employed in practice lie between about 50% and

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)

Abstract

Compresseur à une seule vis possédant au moins deux chambres de pompage (10A, 10B) de volume variable formées dans les cannelures d'une vis. Chacune d'elles reçoit d'une admission principale (14; 34) un fluide devant être comprimé lorsque la chambre de pompage respective renferme un premier volume au moins proche de son volume maximum, et chacune d'elles évacue le fluide comprimé par une orifice d'évacuation (13a, 13b) lorsque la chambre de pompage respective renferme un deuxième volume inférieur au premier. L'une des chambres de pompage (10B) comporte une admission secondaire (12b, 36) introduisant le fluide dans ladite chambre (10B) lorsque celle-ci renferme un troisième volume compris entre les premier et deuxième volumes après fermeture de l'admission principale de cette chambre (10B) et avant ouverture de son orifice d'évacuation. Ce compresseur se caractérise en ce qu'il comporte un dispositif (38a, 38b; 40) permettant le raccordement de l'orifice d'évacuation de l'autre chambre de pompage (10A) avec l'admission secondaire (12b, 36) de la première chambre de pompage (10B).
PCT/GB1996/002678 1995-11-02 1996-11-01 Ameliorations apportees a des compresseurs a une seule vis WO1997016648A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU73225/96A AU7322596A (en) 1995-11-02 1996-11-01 Improvements in and relating to single screw compressors

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
GBGB9522516.5A GB9522516D0 (en) 1995-11-02 1995-11-02 Improvements in and relating to single screw compressors
GB9522516.5 1995-11-02
GB9522517.3 1995-11-02
GBGB9522517.3A GB9522517D0 (en) 1995-11-02 1995-11-02 Improved compressor arrangement
KEPCT/GB96/02677 1996-11-01
PCT/GB1996/002677 WO1997016647A1 (fr) 1995-11-02 1996-11-01 Agencement de compresseur ameliore et son procede de fonctionnement

Publications (1)

Publication Number Publication Date
WO1997016648A1 true WO1997016648A1 (fr) 1997-05-09

Family

ID=27267966

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1996/002678 WO1997016648A1 (fr) 1995-11-02 1996-11-01 Ameliorations apportees a des compresseurs a une seule vis

Country Status (1)

Country Link
WO (1) WO1997016648A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7045232B1 (en) 1998-05-20 2006-05-16 Volkswagen Ag Fuel cell system and method for producing electric energy using a fuel cell system
US7160638B1 (en) 1998-05-20 2007-01-09 Volkswagen Ag Fuel cell system and method for generating electrical energy using a fuel cell system
WO2009068187A1 (fr) * 2007-11-28 2009-06-04 Daimler Ag Système de pile à combustible
GB2581204A (en) * 2019-02-11 2020-08-12 J & E Hall Ltd Screw compressor

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1501474A (en) * 1975-07-16 1978-02-15 Uniscrew Ltd Rotary compressors
US4696627A (en) * 1985-08-15 1987-09-29 Nippondenso Co., Ltd. Scroll compressor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1501474A (en) * 1975-07-16 1978-02-15 Uniscrew Ltd Rotary compressors
US4696627A (en) * 1985-08-15 1987-09-29 Nippondenso Co., Ltd. Scroll compressor

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7045232B1 (en) 1998-05-20 2006-05-16 Volkswagen Ag Fuel cell system and method for producing electric energy using a fuel cell system
US7160638B1 (en) 1998-05-20 2007-01-09 Volkswagen Ag Fuel cell system and method for generating electrical energy using a fuel cell system
WO2009068187A1 (fr) * 2007-11-28 2009-06-04 Daimler Ag Système de pile à combustible
GB2581204A (en) * 2019-02-11 2020-08-12 J & E Hall Ltd Screw compressor
WO2020165561A1 (fr) * 2019-02-11 2020-08-20 J & E Hall Limited Compresseur à vis
GB2581204B (en) * 2019-02-11 2022-07-20 J & E Hall Ltd Screw compressor

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