EP1687539A1 - Compressor - Google Patents

Compressor

Info

Publication number
EP1687539A1
EP1687539A1 EP04775488A EP04775488A EP1687539A1 EP 1687539 A1 EP1687539 A1 EP 1687539A1 EP 04775488 A EP04775488 A EP 04775488A EP 04775488 A EP04775488 A EP 04775488A EP 1687539 A1 EP1687539 A1 EP 1687539A1
Authority
EP
European Patent Office
Prior art keywords
compressor
pressure
motor
speed
tank
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.)
Withdrawn
Application number
EP04775488A
Other languages
German (de)
English (en)
French (fr)
Inventor
Mats SUNDSTRÖM
Henrik ÖHMAN
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.)
Svenska Rotor Maskiner AB
Original Assignee
Svenska Rotor Maskiner AB
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 Svenska Rotor Maskiner AB filed Critical Svenska Rotor Maskiner AB
Publication of EP1687539A1 publication Critical patent/EP1687539A1/en
Withdrawn legal-status Critical Current

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
    • 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
    • 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
    • F04C28/08—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by varying the rotational speed

Definitions

  • the present invention relates to a speed-regulated helical screw rotor compressor that is adapted to work against a pressure container whose pressure P lies within the working range of the compressor and which is allowed to vary between a lowest pressure and a highest pressure.
  • the compressor is driven by an electric motor. Small pressure variations are desirable in such a pressure container or accumulator tank. In the case of a large accumulator tank this can be achieved with a highly frequent start-stop control facility or by regulating the speed (r.p.m.) of the motor.
  • Compressor speed control is generally used in respect of air compressors that are driven by a high power motor down to a power of 10-30 kW. The compressor speed is controlled with the aid of electronic control means.
  • a smart way of controlling the pressure in the pressure container is to use in the container a pressure sensor which, via appropriate control means, functions to switch-off the compressor motor when the pressure in the container has reached its maximum value and to switch-on the motor when the container pressure has reached a pre-determined lowest value.
  • the aim of the present invention is to provide a motor-driven compressor whose motor has a much smaller power than the aforesaid lowest power and the speed of which can be controlled at least within one working range in the absence of expensive control equipment.
  • This aim is achieved in accordance with the invention with a compressor that is driven by a motor whose speed is significantly dependant on the torque or moment index within a given working range. Preferred embodiments will be apparent from the dependent claims.
  • Figure 1 is a longitudinally sectional view of a known helical screw compressor
  • Figure 2 is a sectional view taken on the line II-II in fig.
  • FIG. 1 Figure 3 is a diagrammatic illustration of a system which includes the compressor; Figure 4 illustrates diagrammatically the torque of a typical compressor motor as a function of its speed (r.p.m.); and Figure 5 is a corresponding diagrammatic illustration of a compressor motor according to the present invention.
  • a brief description of the construction and working principle of a helical screw compressor will now be given with reference to figures 1 and 2.
  • a pair of mutually engaging screw rotors 101, 102 are mounted for rotation in a working space delimited by two end walls 103, 104 and including a barrel wall 105 that extends between said end walls.
  • the barrel wall 105 has a form which corresponds generally to that of two mutually intersecting cylinders, as evident from figure 2.
  • Each rotor 101, 102 includes a plurality of lobes 106 and 107 respectively, and respective intermediate grooves 1 1 1 and 112 that extend in a helical line along the rotor.
  • One rotor 101 is a male type of rotor with the major part of each lobe 106 located outside the pitch circle and the other rotor 102 is a female type rotor with the major part of each lobe 107 located inwardly of the pitch circle.
  • the female rotor 102 will usually have more lobes than the male rotor 101.
  • a typical combination is one in which the male rotor 101 has four lobes and the female rotor 102 has six lobes.
  • the gas to be compressed normally air, is delivered to a working space of the compressor through an inlet port 108 and is then compressed in V-shaped working chambers formed between the rotors and the walls of the working space.
  • Each working chamber moves to the right in figure 1 as the rotors 101, 102 rotate.
  • the volume of a working chamber will thus decrease continuously during the latter part of its cycle, subsequent to communication with the inlet port having been cut off.
  • the gas is thereby compressed and exits in a compressed state from the compressor through an outlet port 109.
  • the ratio between outlet pressure and inlet pressure is determined by the inherent volumetric relationship between the volume of a working chamber immediately after its communication with the inlet port 108 has been cut off, and the volume of said chamber when it begins to communicate with the outlet port 109.
  • FIG. 3 illustrates a compressor K, preferably a helical screw compressor, which is driven by a motor M via a shaft or axle 1.
  • the compressor includes an inlet port 6 into which an inlet line 2 opens.
  • the line 2 includes a check valve 3 which allows air to enter the compressor, while preventing the flow of air in the opposite direction.
  • the compressor has at its other end an outlet port 7 which is connected to a pressure tank T via a line 4.
  • One or more tools V driven by compressed air, are supplied with pressure from the tank T via a line 5.
  • the tank is provided with a pressure sensor 9 which is connected via a signal transmitting line 10 to a control means 8 that functions to control starting and stopping of the motor.
  • the pressure in the tank T shall vary between a highest pressure PI and a lowest pressure P2.
  • FIG. 4 illustrates diagrammatically a torque curve as a function of the rotational speed of an asynchronous motor. The axes are not graduated.
  • the motor has a speed of N for a torque of M 2A - When the torque of the motor increases to M 1A , the motor speed will drop to N 3 .
  • the relationship with respect to this asynchronous motor is at least substantially linear in one working range of said motor.
  • the motor will be started when the tank pressure has fallen to the pressure P2, wherewith the compressor begins to compress air.
  • the compressor will work at almost maximum capacity in this torque range. This results in a rapid increase in tank pressure.
  • a compressor driven by an asynchronous motor will thus result in a short compressor operating time in achieving the desired highest pressure in the tank T.
  • figure 5 illustrates diagrammatically a torque curve as a function of motor speed.
  • the illustrated curve of figure 5 relates to a commutator motor.
  • the axes shown in figure 5 are not graduated.
  • the torques Mi k and M 2 k in figure 5 correspond to the torques M IA and M 2A in figure 4.
  • the commutator motor has a speed of N2 in respect of torqueM 2 k-
  • torqueM 2 k- When the torque of said motor has increased to Muc, the rpm of the motor will have fallen to NL This relationship is at least substantially linear for the commutator in the working range.
  • the tank pressure will have fallen to P 2k when the motor is started (see fig. 3) wherewith the compressor begins to compress air. Due to the significant increase in rpm.
  • internal volume factor is meant the relationship between the minimum and maximum thread volume enclosed in the helical rotor compressor used.
  • the internal volume factor will preferably be such that the pressure of the compressor K will be less than P2 + 0.85 * (P1-P2) when the thread volume of the working chamber that commences communication with the tank T has its minimum volume. This means that the compressor outlet pressure in given working chamber will be at most equal to the lowest pressure of the tank plus 85 percent of the difference between the highest and the lowest pressure of the tank.
  • the compressor will preferably be optimised for an internal volume factor at which the compressor pressure at the opening instance will be equal to the lowest working pressure P2 in the pressure container. It is particularly preferred that the compressor is optimised in respect of an internal volume factor at which the compressor pressure at the opening instance is lower than the lowest working pressure P2 in the pressure container.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
  • Control Of Electric Motors In General (AREA)
  • Control Of Direct Current Motors (AREA)

Abstract

Sammandrag Skruvrotorkompressor (K), som är avsedd att arbeta mot en tryckbehållare (T), vars tryck P får variera mellan ett lägsta tryck P2 och ett högsta tryck P1, vilken kom-pressor drives av en elektrisk motor (M). Det utmärkande för den elektriska motorn (M) är, att den har en sådan karakteristik i ett driftområde, som är definierat av tryckkärlets tryckintervall P, att en halvering av motorns moment ger en ökning av dess varvtal med minst 6 procent. Det är vidare föredraget, att kompressorn är optimerad för ett inre volymförhållande, vid vilket kompressorns tryck i öppningsögonblicket är lägre än P2 + 0,85 . (P1 - P2).
EP04775488A 2003-10-17 2004-09-30 Compressor Withdrawn EP1687539A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0302739A SE0302739L (sv) 2003-10-17 2003-10-17 Varvtalsreglerad skruvrotorkompressor
PCT/SE2004/001390 WO2005038257A1 (en) 2003-10-17 2004-09-30 Compressor

Publications (1)

Publication Number Publication Date
EP1687539A1 true EP1687539A1 (en) 2006-08-09

Family

ID=29398751

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04775488A Withdrawn EP1687539A1 (en) 2003-10-17 2004-09-30 Compressor

Country Status (7)

Country Link
US (1) US20070207045A1 (sv)
EP (1) EP1687539A1 (sv)
JP (1) JP2007508494A (sv)
KR (1) KR20060097018A (sv)
CN (1) CN100458164C (sv)
SE (1) SE0302739L (sv)
WO (1) WO2005038257A1 (sv)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE1020311A3 (nl) * 2012-02-28 2013-07-02 Atlas Copco Airpower Nv Schroefcompressor.
BE1020312A3 (nl) * 2012-02-28 2013-07-02 Atlas Copco Airpower Nv Compressorinrichting, evenals gebruik van zulke opstelling.
US11015602B2 (en) 2012-02-28 2021-05-25 Atlas Copco Airpower, Naamloze Vennootschap Screw compressor
EP3118458B1 (en) * 2015-07-15 2017-08-30 ABB Technology Oy Method and apparatus in connection with a screw compressor

Family Cites Families (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3855515A (en) * 1972-03-06 1974-12-17 Waters Associates Inc Motor control circuit
US3860363A (en) * 1973-05-10 1975-01-14 Chicago Pneumatic Tool Co Rotary compressor having improved control system
US4052135A (en) * 1976-05-11 1977-10-04 Gardner-Denver Company Control system for helical screw compressor
US4068980A (en) * 1976-10-01 1978-01-17 Gardner-Denver Company Compressor startup control
CH660100A5 (fr) * 1981-12-18 1987-03-13 Cerac Inst Sa Dispositif d'entrainement d'un compresseur.
US4686439A (en) * 1985-09-10 1987-08-11 A. T. Hunn Company Multiple speed pump electronic control system
JPS6338693A (ja) * 1986-07-31 1988-02-19 Nippon Air Brake Co Ltd 鉄道車両用調圧方法
CN1011728B (zh) * 1986-12-15 1991-02-20 瑞典转子机械公司 螺杆压缩机
US5602957A (en) * 1993-06-07 1997-02-11 General Electric Company Permanent magnet direct current motor
CN2155519Y (zh) * 1993-06-30 1994-02-09 李敬茂 节能空调器
US5580221A (en) * 1994-10-05 1996-12-03 Franklin Electric Co., Inc. Motor drive circuit for pressure control of a pumping system
FI104205B1 (sv) * 1994-11-24 1999-11-30 Sarlin Hydor Oy Förfarande och anordning för styrning av ett kompressionssystem för ett flytande medium
DE9419651U1 (de) * 1994-12-08 1995-02-02 Hatlapa Uetersener Maschf Kompressoranlage
US5979168A (en) * 1997-07-15 1999-11-09 American Standard Inc. Single-source gas actuation for screw compressor slide valve assembly
US6146101A (en) * 1998-05-22 2000-11-14 Chang; Ming-Yi Automatic control device for an air compressor
JP3837278B2 (ja) * 2000-08-10 2006-10-25 株式会社神戸製鋼所 圧縮機の運転方法
GB2376505B (en) * 2001-06-11 2003-12-17 Compair Uk Ltd Improvements in screw compressors
JP4069450B2 (ja) * 2003-06-24 2008-04-02 日立工機株式会社 空気圧縮機及びその制御方法
US7081698B1 (en) * 2003-07-31 2006-07-25 Black & Decker Inc. Efficient motor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2005038257A1 *

Also Published As

Publication number Publication date
KR20060097018A (ko) 2006-09-13
SE524343C2 (sv) 2004-07-27
SE0302739L (sv) 2004-07-27
JP2007508494A (ja) 2007-04-05
SE0302739D0 (sv) 2003-10-17
US20070207045A1 (en) 2007-09-06
CN100458164C (zh) 2009-02-04
WO2005038257A1 (en) 2005-04-28
CN1867775A (zh) 2006-11-22

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