EP0389036A1 - Screw compressor and method of operation thereof - Google Patents

Screw compressor and method of operation thereof Download PDF

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Publication number
EP0389036A1
EP0389036A1 EP90200581A EP90200581A EP0389036A1 EP 0389036 A1 EP0389036 A1 EP 0389036A1 EP 90200581 A EP90200581 A EP 90200581A EP 90200581 A EP90200581 A EP 90200581A EP 0389036 A1 EP0389036 A1 EP 0389036A1
Authority
EP
European Patent Office
Prior art keywords
stator housing
compressor
water
gas
injected
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP90200581A
Other languages
German (de)
French (fr)
Other versions
EP0389036B1 (en
Inventor
Hans Hendrik Jantzen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Grass-Air Holding BV
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Grass-Air Holding BV
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 Grass-Air Holding BV filed Critical Grass-Air Holding BV
Publication of EP0389036A1 publication Critical patent/EP0389036A1/en
Application granted granted Critical
Publication of EP0389036B1 publication Critical patent/EP0389036B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/0007—Injection of a fluid in the working chamber for sealing, cooling and lubricating

Definitions

  • the invention relates to a screw compressor with two parallel screws engaging with each other, one of which is driven while the other is carried, surrounded by a stator housing and provided with an inlet for the gas to be compressed and an outlet for the compressed gas, said stator housing also having at least one inlet through which water is injected into the stator housing, and to a method of operation thereof.
  • water only is injected at one point, i.e. near the outlet for the compressed gas.
  • the purpose of the water injection is to lower the temperature of the compressed gas and make it as far as possible the same as the inlet temperature of the gas, in particular air.
  • a so-called oil-free compressor therefore has great advantages, but no practical embodiments are known in practice.
  • the object of the invention is to produce a compressor and a method of operation thereof by means of which it is in fact possible to obtain isothermal compression economically with water injection alone, provided that a number of conditions are met.
  • the screw compressor according to the invention is characterized in that said injection point is located at a place in the stator housing where the pressure is equal to 2 3 ⁇ P plus or minus 0.5 bar, and in that further injection points are provided at a place in the stator housing where the pressure is equal to 3 ⁇ P plus or minus 0.5 bar and at the inlet side of the gas, P being equal to the absolute final pres­sure of the compressor.
  • the water therefore has to be injected simultaneously at several, very specific points.
  • the method according to the invention is characterized in that the quantity of water injected per unit time is between 1% and 2% of the capacity of the compressor, and the temperature of the injected water is at least 5 K lower than the temperature of the gas at the inlet of the compressor.
  • the compressor which is conventional per se, comprises a screw 1 with a driving shaft 2.
  • a screw 3 is in engagement with said screw 1 and in operation is carried by the screw 1. There is no mechanical coupling between the two screws or rotors.
  • the screws 1 and 3 are supported in and enclosed by a stator housing 4.
  • the gas to be compressed is fed in at the lefthand side of the housing 4, through a transverse feed 5 (see Fig. 2).
  • the compressed gas is discharged at the righthand side of the housing 4, through an axial outlet 6.
  • an injection point is located at point A.
  • This injection point A is directed towards the contact face of the rotors 1 and 3.
  • point A lies at a place where the pressure is equal to 2 3 ⁇ P plus or minus 0.5 bar, P being equal to the absolute final pressure at the compressor outlet.
  • the two points B lie at a place where the pressure is equal to 3 ⁇ P plus or minus 0.5 bar.
  • the two points C lie at a place where the pressure is equal to the inlet pressure.
  • the injected quantity of water per unit time must lie between 1% and 2% of the capacity of the compressor.
  • approximately 50% of the total quantity of water must be injected in point A, approximately 20% in each point B, and approximately 5% in each point C.
  • the temperature of the injected water is also of essential impor­tance and must be at least 5 K lower than the temperature of the gas sucked in.
  • the example taken is a compressor with an absolute pressure of 7 bar and a speed of 6,475 rpm.
  • the shaft power is 7.38 kW/m3/min.
  • the shaft power is 6.03 kW/m3/min.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
  • Separation By Low-Temperature Treatments (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

Screw compressor with two parallel screws (1,3) engaging with each other, one of which (1) is driven while the other (3) is carried, surrounded by a stator housing (4) and provided with an inlet for the gas to be compressed and an outlet for the compressed gas, said stator housing also having injection points through which water is injected into the stator housing, whereby one injection point (A) is located at a place in the stator housing where the pressure is equal to 2³√P plus or minus 0.5 bar, and in that further injection points (B) are provided at a place in the stator housing (4) where the pressure is equal to ³√P plus or minus 0.5 bar and injection points (C) at the inlet side of the gas, P being equal to the aboslute final pressure of the compressor.

Description

  • The invention relates to a screw compressor with two parallel screws engaging with each other, one of which is driven while the other is carried, surrounded by a stator housing and provided with an inlet for the gas to be compressed and an outlet for the compressed gas, said stator housing also having at least one inlet through which water is injected into the stator housing, and to a method of operation thereof.
  • Such a compressor and method is known from US Patent Specification 3,535,057, in the embodiment described in Col. 6, lines 29 and 30, i.e. the embodiment without mechanical coupling between the two rotors.
  • In the known compressor and method, water only is injected at one point, i.e. near the outlet for the compressed gas.
  • The purpose of the water injection is to lower the temperature of the compressed gas and make it as far as possible the same as the inlet temperature of the gas, in particular air.
  • It is not stated anywhere in this patent specification that, due to the injection of water, the mechanical coupling between the rotors can also be omitted. Nor are any instructions given concerning the quantity of water to be injected and its temperature.
  • This suggestion, which was already made in 1968, has never been successful in practice. In practice, compressors working without mecha­nical coupling virtually all have oil injection. This oil is then used for lubricating, sealing and cooling of the compressor. After compres­sion, this oil must be carefully removed from the compressed gas, gene­rally air, using expensive oil separators, because the presence of oil in any kind of pneumatic device is disastrous.
  • A so-called oil-free compressor therefore has great advantages, but no practical embodiments are known in practice.
  • The object of the invention is to produce a compressor and a method of operation thereof by means of which it is in fact possible to obtain isothermal compression economically with water injection alone, provided that a number of conditions are met.
  • The screw compressor according to the invention is characterized in that said injection point is located at a place in the stator housing where the pressure is equal to 2 ³√P plus or minus 0.5 bar, and in that further injection points are provided at a place in the stator housing where the pressure is equal to ³√P plus or minus 0.5 bar and at the inlet side of the gas, P being equal to the absolute final pres­sure of the compressor.
  • The water therefore has to be injected simultaneously at several, very specific points.
  • The method according to the invention is characterized in that the quantity of water injected per unit time is between 1% and 2% of the capacity of the compressor, and the temperature of the injected water is at least 5 K lower than the temperature of the gas at the inlet of the compressor.
  • Through these measures a considerable improvement is obtained in the power which is needed to drive the compressor.
  • The invention will be explained in greater detail with reference to schematic drawings, in which:
    • Fig. 1 is a longitudinal section of a conventional screw compres­sor, in which one screw or rotor is driven and the other is carried;
    • Fig. 2 is a view from the rear end of Fig. 1.
  • The compressor, which is conventional per se, comprises a screw 1 with a driving shaft 2.
  • A screw 3 is in engagement with said screw 1 and in operation is carried by the screw 1. There is no mechanical coupling between the two screws or rotors.
  • The screws 1 and 3 are supported in and enclosed by a stator housing 4.
  • The gas to be compressed is fed in at the lefthand side of the housing 4, through a transverse feed 5 (see Fig. 2).
  • The compressed gas is discharged at the righthand side of the housing 4, through an axial outlet 6.
  • In order to ensure an essentially isothermal compression of the gas, generally air, water is injected into the interior of the compres­sor. This water serves not only for cooling of the gas, but also for lubrication of the contact faces of the rotors 1 and 3.
  • In the compressor known from US Patent Specification 3,535,057, this water is injected only at the outlet side of the rotors. In the compressor according to the invention water is injected at different, and at several, places.
  • According to the invention, an injection point is located at point A. This injection point A is directed towards the contact face of the rotors 1 and 3.
  • Viewed in the lengthwise direction of the compressor, point A lies at a place where the pressure is equal to 2 ³√P plus or minus 0.5 bar, P being equal to the absolute final pressure at the compressor outlet.
  • Water is also injected at points B and C.
  • Viewed in the lengthwise direction of the compressor, the two points B lie at a place where the pressure is equal to ³√P plus or minus 0.5 bar.
  • The two points C lie at a place where the pressure is equal to the inlet pressure.
  • It can be seen from the drawings that the two points B and the two points C always lie on either side of the plane in which point A is situated. Points B and C are also preferably slanted outwards.
  • Apart from the place of the injection points, in particular the quantity of injected water and the temperature thereof are of essential importance for the invention.
  • The injected quantity of water per unit time must lie between 1% and 2% of the capacity of the compressor. As regards the distribution of the quantity of water per injection point, according to the invention approximately 50% of the total quantity of water must be injected in point A, approximately 20% in each point B, and approximately 5% in each point C.
  • The temperature of the injected water is also of essential impor­tance and must be at least 5 K lower than the temperature of the gas sucked in.
  • The example taken is a compressor with an absolute pressure of 7 bar and a speed of 6,475 rpm.
  • With oil injection the power at the shaft 2 is 8.33 kw/m³/min.
  • With injection of water in the same compressor in a quantity of 1% - 2% of the compressor capacity and at a temperature which is at least 5 K lower than the temperature of the gas sucked in, the shaft power is 7.38 kW/m³/min.
  • In a compressor with the proposed distribution of the injection points, the shaft power is 6.03 kW/m³/min.
  • By comparison with the oil compressor, a saving of approx. 27% is thus achieved.

Claims (4)

1.Screw compressor with two parallel screws engaging with each other, one of which is driven while the other is carried, surrounded by a stator housing and provided with an inlet for the gas to be compressed and an outlet for the compressed gas, said stator housing also having at least one injection point through which water is injected into the stator housing, characterized in that said injection point is located at a place in the stator housing where the pressure is equal to 2 ³√P plus or minus 0.5 bar, and in that further injection points are provided at a place in the stator housing where the pressure is equal to ³√P plus or minus 0.5 bar and at the inlet side of the gas, P being equal to the absolute final pressure of the compressor.
2.Screw compressor according to Claim 1, characterized in that the first-mentioned injection point is directed towards the contact face between the two screws and the remaining injection points are arranged in two groups of two and slant outwards.
3.Method of driving a screw compressor with two parallel screws engaging with each other, one of which is driven while the other is carried, surrounded by a stator housing and provided with an inlet for the gas to be compressed and an outlet for the compressed gas, said stator housing also having at least one injection point through which water is injected into the stator housing, characterized in that the quantity of water injected per unit time is 1% - 2% of the capacity of the compressor, and the temperature of the injected water is at least 5 K lower than the temperature of the gas at the inlet of the compressor.
4.Method according to Claim 3, characterized in that the quantity of water injected in the first-mentioned injection point is approximate­ly 50% of the total quantity of injected water, in each of the set of injection points located at ³√P plus or minus 0.5 bar it is approxima­tely 20%, and in each of the set of injection points located at the inlet side approximately 5%.
EP90200581A 1989-03-21 1990-03-09 Screw compressor and method of operation thereof Expired - Lifetime EP0389036B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL8900694 1989-03-21
NL8900694A NL8900694A (en) 1989-03-21 1989-03-21 SCREW COMPRESSOR AND METHOD FOR ITS OPERATION.

Publications (2)

Publication Number Publication Date
EP0389036A1 true EP0389036A1 (en) 1990-09-26
EP0389036B1 EP0389036B1 (en) 1993-07-28

Family

ID=19854333

Family Applications (1)

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EP90200581A Expired - Lifetime EP0389036B1 (en) 1989-03-21 1990-03-09 Screw compressor and method of operation thereof

Country Status (6)

Country Link
EP (1) EP0389036B1 (en)
AT (1) ATE92158T1 (en)
DE (1) DE69002358T2 (en)
DK (1) DK0389036T3 (en)
ES (1) ES2043243T3 (en)
NL (1) NL8900694A (en)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993024754A2 (en) * 1992-05-29 1993-12-09 National Power Plc A gas compressor
GB2283543A (en) * 1992-05-29 1995-05-10 Nat Power Plc A gas compressor
WO1996021109A1 (en) * 1994-12-29 1996-07-11 Kirsten Guenter Compressor installation
DE19543879A1 (en) * 1995-11-24 1997-05-28 Guenter Kirsten Screw compressor with liquid injection
USRE37603E1 (en) 1992-05-29 2002-03-26 National Power Plc Gas compressor
US6368091B1 (en) 1998-03-25 2002-04-09 Taiko Kikai Industries Co., Ltd. Screw rotor for vacuum pumps
US6375443B1 (en) * 1998-03-24 2002-04-23 Taiko Kikai Industries Co., Ltd. Screw rotor type wet vacuum pump
WO2018196427A1 (en) * 2017-04-26 2018-11-01 格力电器（武汉）有限公司 Screw compressor, air conditioning device and refrigerating device
WO2019137852A1 (en) * 2018-01-12 2019-07-18 Leybold Gmbh Compressor
CN111094750A (en) * 2017-09-04 2020-05-01 株式会社日立产机系统 Screw compressor
EP3467315B1 (en) * 2017-10-04 2021-03-24 Ingersoll-Rand Industrial U.S., Inc. Screw compressor with oil injection at multiple volume ratios
US11149733B2 (en) * 2016-08-01 2021-10-19 Atlas Copco Airpower, Naamloze Vennootschap Liquid-injected compressor or expander element and method for controlling the liquid injection of a compressor or expander device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3535057A (en) * 1968-09-06 1970-10-20 Esper Kodra Screw compressor
GB1413426A (en) * 1973-04-09 1975-11-12 Zimmern B Rotary air compressor sets with injection of water
DE2801408A1 (en) * 1978-01-13 1979-07-19 Linde Ag Refrigeration unit rotary piston compressor cooling system - injects oil and refrigerant mixture into compression chamber
DE2853264A1 (en) * 1978-12-09 1980-06-19 Rietschle Masch App Vacuum pump with injection cooling - injects water instead of oil, which also acts as sealant, lubricant and cleaning agent
FR2603666A1 (en) * 1986-09-10 1988-03-11 Zimmern Bernard Injected compressor with liquid switch-over

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3535057A (en) * 1968-09-06 1970-10-20 Esper Kodra Screw compressor
GB1413426A (en) * 1973-04-09 1975-11-12 Zimmern B Rotary air compressor sets with injection of water
DE2801408A1 (en) * 1978-01-13 1979-07-19 Linde Ag Refrigeration unit rotary piston compressor cooling system - injects oil and refrigerant mixture into compression chamber
DE2853264A1 (en) * 1978-12-09 1980-06-19 Rietschle Masch App Vacuum pump with injection cooling - injects water instead of oil, which also acts as sealant, lubricant and cleaning agent
FR2603666A1 (en) * 1986-09-10 1988-03-11 Zimmern Bernard Injected compressor with liquid switch-over

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE37603E1 (en) 1992-05-29 2002-03-26 National Power Plc Gas compressor
US5771693A (en) * 1992-05-29 1998-06-30 National Power Plc Gas compressor
WO1993024754A2 (en) * 1992-05-29 1993-12-09 National Power Plc A gas compressor
GB2283543A (en) * 1992-05-29 1995-05-10 Nat Power Plc A gas compressor
WO1993024754A3 (en) * 1992-05-29 1994-03-17 Nat Power Plc A gas compressor
US6102683A (en) * 1994-12-29 2000-08-15 Kirsten; Guenter Compressor installation having water injection and a water treatment device
AU701216B2 (en) * 1994-12-29 1999-01-21 Gunter Kirsten Compressor installation
CN1079504C (en) * 1994-12-29 2002-02-20 京特·基尔斯滕 Compressor installation
WO1996021109A1 (en) * 1994-12-29 1996-07-11 Kirsten Guenter Compressor installation
DE19543879A1 (en) * 1995-11-24 1997-05-28 Guenter Kirsten Screw compressor with liquid injection
DE19543879C2 (en) * 1995-11-24 2002-02-28 Guenter Kirsten Screw compressor with liquid injection
US6375443B1 (en) * 1998-03-24 2002-04-23 Taiko Kikai Industries Co., Ltd. Screw rotor type wet vacuum pump
US6368091B1 (en) 1998-03-25 2002-04-09 Taiko Kikai Industries Co., Ltd. Screw rotor for vacuum pumps
US11149733B2 (en) * 2016-08-01 2021-10-19 Atlas Copco Airpower, Naamloze Vennootschap Liquid-injected compressor or expander element and method for controlling the liquid injection of a compressor or expander device
WO2018196427A1 (en) * 2017-04-26 2018-11-01 格力电器（武汉）有限公司 Screw compressor, air conditioning device and refrigerating device
EP3680485A4 (en) * 2017-09-04 2020-12-23 Hitachi Industrial Equipment Systems Co., Ltd. Screw compressor
CN111094750A (en) * 2017-09-04 2020-05-01 株式会社日立产机系统 Screw compressor
CN111094750B (en) * 2017-09-04 2022-04-15 株式会社日立产机系统 Screw compressor
EP3467315B1 (en) * 2017-10-04 2021-03-24 Ingersoll-Rand Industrial U.S., Inc. Screw compressor with oil injection at multiple volume ratios
US11118585B2 (en) 2017-10-04 2021-09-14 Ingersoll-Rand Industrial U.S., Inc. Screw compressor with oil injection at multiple volume ratios
CN114857004A (en) * 2017-10-04 2022-08-05 英格索兰工业美国公司 Screw compressor with oil injection at multiple volume ratios
US11732715B2 (en) 2017-10-04 2023-08-22 Ingersoll-Rand Industrial U.S., Inc. Screw compressor with oil injection at multiple volume ratios
WO2019137852A1 (en) * 2018-01-12 2019-07-18 Leybold Gmbh Compressor

Also Published As

Publication number Publication date
NL8900694A (en) 1990-10-16
ATE92158T1 (en) 1993-08-15
DE69002358D1 (en) 1993-09-02
DK0389036T3 (en) 1993-09-27
ES2043243T3 (en) 1993-12-16
DE69002358T2 (en) 1994-02-10
EP0389036B1 (en) 1993-07-28

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