US20120014777A1 - Method for controlling a regulated-rotation-speed low-pressure centrifugal fan - Google Patents

Method for controlling a regulated-rotation-speed low-pressure centrifugal fan Download PDF

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Publication number
US20120014777A1
US20120014777A1 US12/851,190 US85119010A US2012014777A1 US 20120014777 A1 US20120014777 A1 US 20120014777A1 US 85119010 A US85119010 A US 85119010A US 2012014777 A1 US2012014777 A1 US 2012014777A1
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US
United States
Prior art keywords
valve
centrifugal fan
seconds
stalling
rotation
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.)
Abandoned
Application number
US12/851,190
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English (en)
Inventor
Jouni Mussalo
Mauri Vuohelainen
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.)
Runtech Systems Oy
Original Assignee
Runtech Systems Oy
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 Runtech Systems Oy filed Critical Runtech Systems Oy
Assigned to RUNTECH SYSTEMS OY reassignment RUNTECH SYSTEMS OY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MUSSALO, JOUNI, VUOHELAINEN, MAURI
Publication of US20120014777A1 publication Critical patent/US20120014777A1/en
Priority to US14/047,555 priority Critical patent/US8961149B2/en
Abandoned 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
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/009—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by bleeding, by passing or recycling fluid
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B15/00—Systems controlled by a computer
    • G05B15/02—Systems controlled by a computer electric
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/001—Testing thereof; Determination or simulation of flow characteristics; Stall or surge detection, e.g. condition monitoring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/02—Surge control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/02—Surge control
    • F04D27/0207—Surge control by bleeding, bypassing or recycling fluids
    • F04D27/0215—Arrangements therefor, e.g. bleed or by-pass valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/004—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by varying driving speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2270/00—Control
    • F05D2270/01—Purpose of the control system
    • F05D2270/10—Purpose of the control system to cope with, or avoid, compressor flow instabilities
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2270/00—Control
    • F05D2270/30—Control parameters, e.g. input parameters
    • F05D2270/303—Temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2270/00—Control
    • F05D2270/30—Control parameters, e.g. input parameters
    • F05D2270/335—Output power or torque
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

  • a method for controlling an automatic stall-prevention of regulated-rotation-speed low-pressure centrifugal fan and a control automatics therefor is known in the art. Particularly in industry, centrifugal fans, compressors and radial fans are widely used to achieve a pressure difference in piping.
  • a problem for all centrifugal fan is generally known to be stalling. In other words, stalling is a characteristic state for all centrifugal fans, which occurs when the volume flow rate is too small in relation to the speed of rotation of the impeller. In this case the angle of incidence between the flow and the blade changes to be so disadvantageous that the flow disengages from the surface of the blade. Backflow is then able to occur in the blade passage and the impeller loses its pressure-increasing ability.
  • centrifugal fans that have a constant speed of rotation have been used. In this case stalling is prevented with an automatic leakage air valve, which receives control from the current of the drive motor of the centrifugal fan. In the stalling state the current of the drive motor is smaller than in the normal operating range. The electric current also fluctuates strongly.
  • the control logic of the centrifugal fan can easily be programmed to detect a stalling state and to eliminate it by means of leakage air.
  • Another problem is that in a stalling state the low pressure also fluctuates with a rapid cycle, and this situation is detrimental from the viewpoint of the process.
  • a device that has a regulated speed of rotation has been launched in the low-pressure centrifugal fan market as a new technology, the stall control of which cannot be implemented with conventional technology.
  • a device with a regulated rotation speed is provided, and that is in itself prior art, that can now be more precisely utilized.
  • a solution is obtained with which a centrifugal fan can be implemented in which the prior-art problems described above do not occur.
  • the efficiency of the different possibilities of a centrifugal fan can now be significantly enhanced and at the same time the operation of the whole apparatus can be optimized.
  • FIG. 1 is a schematic view of a device according to the present invention.
  • FIG. 1 it is essential in the invention that the points between different flow quantities and the speeds of rotation corresponding to them when stalling starts, and more particularly when it ends, are determined by test-running and with measurements.
  • a limit or range can be mathematically interpolated when lapsing into a stall is evident. Moving to this limit or into this range is prevented by giving more flow to the centrifugal fan from outside the actual intake object as leakage air or, alternatively, from a second intake object. Additional flow is given after an adjustable mathematical safety limit has been exceeded and the additional flow is reduced after falling below a second mathematical limit.
  • These limits follow each other at a distance from each other, which distance is set by the adjustable hysteresis factor.
  • the speed of rotation of the centrifugal fan is measured constantly with a frequency converter or with a separate measuring apparatus.
  • the flow of air/gas is calculated by means of the electric current and voltage going to the motor of the centrifugal fan, as well as by means of the temperature and pressure of the flow, or with a separate measuring apparatus designed for it.
  • the control automatics controls the valve that adjusts the additional flow on the basis of the aforementioned measured data and calculated stalling limit.
  • a calculated stall curve is defined for each centrifugal fan in the commissioning of it and with its actual piping. In this way stalling points at different speeds are sought, and the voltage and electric current are measured after coming out of the stall, at the same time checking whether it is possible to stay outside a stalling state.
  • the flow resistance of the piping is adjusted from the most final point possible such that all the air volume of the pipe is included when determining the points. The factors in the formula below are determined from these points.
  • the final adjustment is made after programming the curve and then the final variable of the quadratic equation, with which variable the curve can be raised or lowered, is changed. In this way the most precise operation possible is achieved for the valve.
  • a stalling state of the centrifugal fan is detected from a function of the current, voltage and frequency going to the motor. According to the calculated result, the stall-prevention valve is either opened or closed according to the need. In addition, the effect of the temperature of the flow is taken into account in the formula.
  • the valve control is repeated e.g. at intervals of 5 seconds or of another applicable time.
US12/851,190 2010-07-19 2010-08-05 Method for controlling a regulated-rotation-speed low-pressure centrifugal fan Abandoned US20120014777A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US14/047,555 US8961149B2 (en) 2010-07-19 2013-10-07 Method for controlling a regulated-rotation-speed low-pressure centrifugal fan

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20105810A FI125258B (fi) 2010-07-19 2010-07-19 Menetelmä pyörimisnopeussäädetyn alipainekeskipakopuhaltimen ohjaamiseksi
FI20105810 2010-07-19

Related Child Applications (1)

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US14/047,555 Continuation-In-Part US8961149B2 (en) 2010-07-19 2013-10-07 Method for controlling a regulated-rotation-speed low-pressure centrifugal fan

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US20120014777A1 true US20120014777A1 (en) 2012-01-19

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US12/851,190 Abandoned US20120014777A1 (en) 2010-07-19 2010-08-05 Method for controlling a regulated-rotation-speed low-pressure centrifugal fan

Country Status (12)

Country Link
US (1) US20120014777A1 (ko)
EP (1) EP2630376B1 (ko)
JP (1) JP5995371B2 (ko)
KR (1) KR101844096B1 (ko)
CN (1) CN103026075B (ko)
AT (1) AT517649A1 (ko)
BR (1) BR112013001497B1 (ko)
CA (1) CA2805080C (ko)
CH (1) CH705542B1 (ko)
FI (1) FI125258B (ko)
SE (1) SE538445C2 (ko)
WO (1) WO2012010741A2 (ko)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102840182A (zh) * 2012-09-10 2012-12-26 中国能源建设集团广东省电力设计研究院 火电厂轴流风机低负荷防振方法及旁路风道控制回路
CN103821749A (zh) * 2014-03-05 2014-05-28 北京工业大学 一种轴流式通风机失速和喘振的在线诊断方法
US10527047B2 (en) * 2017-01-25 2020-01-07 Energy Labs, Inc. Active stall prevention in centrifugal fans
CN112966400A (zh) * 2021-04-23 2021-06-15 重庆大学 一种基于多源信息融合的离心风机趋势预测方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111536554B (zh) * 2020-05-21 2022-02-08 哈尔滨工业大学 一种防止触发锅炉mft的引风机失速控制方法
CN111946651B (zh) * 2020-08-12 2022-04-12 中国大唐集团科学技术研究院有限公司华东电力试验研究院 一种风机失速预警方法及系统

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4322668A (en) * 1976-11-12 1982-03-30 Canadian General Electric Company Ltd. Power control of a stalling motor
US4525660A (en) * 1983-02-17 1985-06-25 Mitsubishi Denki Kabushiki Kaisha Control apparatus for inverter
US4659976A (en) * 1985-04-24 1987-04-21 Dresser Industries, Inc. Method and apparatus for maximizing utilization of an electric motor under load
US5320499A (en) * 1991-09-12 1994-06-14 Vickers Systems Limited Open-loop hydraulic supply system
US6092029A (en) * 1998-02-19 2000-07-18 Bently Nevada Corporation Method and apparatus for diagnosing and controlling rotating stall and surge in rotating machinery
US20020018721A1 (en) * 1997-04-25 2002-02-14 Makoto Kobayashi Fluid machinery
US6501629B1 (en) * 2000-10-26 2002-12-31 Tecumseh Products Company Hermetic refrigeration compressor motor protector
US6868906B1 (en) * 1994-10-14 2005-03-22 Weatherford/Lamb, Inc. Closed-loop conveyance systems for well servicing
US20080074063A1 (en) * 2006-09-22 2008-03-27 Switched Reluctance Drives Limited Operating electrical machines from a DC link
WO2009007681A2 (en) * 2007-07-07 2009-01-15 Trw Limited Electric motor control
US20090019925A1 (en) * 2006-01-26 2009-01-22 Dynatrend As Method and Device for Determining the Occurrence of Rotating Stall in a Compressor's Turbine Blade II
US20110163704A1 (en) * 2010-01-06 2011-07-07 Gm Global Technology Operations, Inc. Method and apparatus for monitoring a system including a sensorless electric motor

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4452585A (en) * 1980-06-02 1984-06-05 Southwire Company Combustion air blower surge control for a melting furnace
US4753711A (en) * 1984-01-31 1988-06-28 Albany International Corp. Surge control system and method for dewatering press felts
AU570120B2 (en) * 1984-10-26 1988-03-03 Albany International Corp. Surge control system in dewatering press felts
US4581900A (en) * 1984-12-24 1986-04-15 Borg-Warner Corporation Method and apparatus for detecting surge in centrifugal compressors driven by electric motors
JPH0816479B2 (ja) * 1987-06-23 1996-02-21 株式会社日立製作所 圧縮機のサ−ジング防止装置
US5447414A (en) * 1994-05-27 1995-09-05 Emerson Electric Co. Constant air flow control apparatus and method
US5746062A (en) * 1996-04-11 1998-05-05 York International Corporation Methods and apparatuses for detecting surge in centrifugal compressors
JPH1162887A (ja) * 1997-08-08 1999-03-05 Nippon Steel Corp 送風機のサージング検出装置、検出方法及びサージング修正方法
US6354806B1 (en) * 2000-03-27 2002-03-12 Micon Systems, Llc Compressor incipient surge detection system
EP1286458A1 (de) * 2001-08-22 2003-02-26 Pumpenfabrik Ernst Vogel Gesellschaft m.b.H. Verfahren und Vorrichtung zur Regelung von Kreiselarbeitsmaschinen
DE102004060206B3 (de) * 2004-12-14 2006-06-14 Siemens Ag Verfahren zum Betrieb eines stromrichtergespeisten Verdichters
JP2007009740A (ja) * 2005-06-28 2007-01-18 Mitsubishi Motors Corp 電動コンプレッサの制御装置
CN101033744B (zh) * 2006-03-08 2013-07-24 Itt制造企业公司 不使用传统传感器的泵保护方法和设备
US8672733B2 (en) * 2007-02-06 2014-03-18 Nordyne Llc Ventilation airflow rate control
DE102007035712B4 (de) * 2007-07-30 2009-12-17 Siemens Ag Verfahren zum Erkennen eines Störfalles "Rotating Stall" bei einem umrichtergespeisten Verdichter
EP2042743B1 (en) * 2007-09-27 2014-11-05 ABB Research Ltd. A gas compression system and a method for controlling a gas compression system.

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4322668A (en) * 1976-11-12 1982-03-30 Canadian General Electric Company Ltd. Power control of a stalling motor
US4525660A (en) * 1983-02-17 1985-06-25 Mitsubishi Denki Kabushiki Kaisha Control apparatus for inverter
US4659976A (en) * 1985-04-24 1987-04-21 Dresser Industries, Inc. Method and apparatus for maximizing utilization of an electric motor under load
US5320499A (en) * 1991-09-12 1994-06-14 Vickers Systems Limited Open-loop hydraulic supply system
US6868906B1 (en) * 1994-10-14 2005-03-22 Weatherford/Lamb, Inc. Closed-loop conveyance systems for well servicing
US20020018721A1 (en) * 1997-04-25 2002-02-14 Makoto Kobayashi Fluid machinery
US6092029A (en) * 1998-02-19 2000-07-18 Bently Nevada Corporation Method and apparatus for diagnosing and controlling rotating stall and surge in rotating machinery
US6501629B1 (en) * 2000-10-26 2002-12-31 Tecumseh Products Company Hermetic refrigeration compressor motor protector
US20090019925A1 (en) * 2006-01-26 2009-01-22 Dynatrend As Method and Device for Determining the Occurrence of Rotating Stall in a Compressor's Turbine Blade II
US20080074063A1 (en) * 2006-09-22 2008-03-27 Switched Reluctance Drives Limited Operating electrical machines from a DC link
WO2009007681A2 (en) * 2007-07-07 2009-01-15 Trw Limited Electric motor control
US20100194325A1 (en) * 2007-07-07 2010-08-05 Christopher David Dixon Electric motor control
US20110163704A1 (en) * 2010-01-06 2011-07-07 Gm Global Technology Operations, Inc. Method and apparatus for monitoring a system including a sensorless electric motor

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102840182A (zh) * 2012-09-10 2012-12-26 中国能源建设集团广东省电力设计研究院 火电厂轴流风机低负荷防振方法及旁路风道控制回路
CN103821749A (zh) * 2014-03-05 2014-05-28 北京工业大学 一种轴流式通风机失速和喘振的在线诊断方法
US10527047B2 (en) * 2017-01-25 2020-01-07 Energy Labs, Inc. Active stall prevention in centrifugal fans
CN112966400A (zh) * 2021-04-23 2021-06-15 重庆大学 一种基于多源信息融合的离心风机趋势预测方法

Also Published As

Publication number Publication date
SE1350052A1 (sv) 2013-01-16
SE538445C2 (sv) 2016-07-05
JP2013531183A (ja) 2013-08-01
JP5995371B2 (ja) 2016-09-21
CA2805080A1 (en) 2012-01-26
AT517649A1 (de) 2017-03-15
KR20140005841A (ko) 2014-01-15
FI20105810A0 (fi) 2010-07-19
BR112013001497B1 (pt) 2020-12-15
FI20105810A (fi) 2012-01-20
EP2630376A2 (en) 2013-08-28
WO2012010741A3 (en) 2012-03-15
EP2630376A4 (en) 2018-04-04
WO2012010741A2 (en) 2012-01-26
KR101844096B1 (ko) 2018-03-30
CA2805080C (en) 2019-06-04
FI20105810L (fi) 2012-01-20
FI125258B (fi) 2015-08-14
EP2630376B1 (en) 2023-04-05
CN103026075B (zh) 2016-05-18
CH705542B1 (de) 2017-06-15
BR112013001497A2 (pt) 2016-05-31
CN103026075A (zh) 2013-04-03

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