EP0179658B1 - Vakuumüberwachungssystem - Google Patents

Vakuumüberwachungssystem Download PDF

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Publication number
EP0179658B1
EP0179658B1 EP85307666A EP85307666A EP0179658B1 EP 0179658 B1 EP0179658 B1 EP 0179658B1 EP 85307666 A EP85307666 A EP 85307666A EP 85307666 A EP85307666 A EP 85307666A EP 0179658 B1 EP0179658 B1 EP 0179658B1
Authority
EP
European Patent Office
Prior art keywords
exhauster
drive motor
surge
centrifugal exhauster
speed
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.)
Expired
Application number
EP85307666A
Other languages
English (en)
French (fr)
Other versions
EP0179658A3 (en
EP0179658A2 (de
Inventor
Joseph A. Bolton
Phillip L. Adamczyk
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.)
Albany International Corp
Original Assignee
Albany International Corp
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 Albany International Corp filed Critical Albany International Corp
Priority to AT85307666T priority Critical patent/ATE43377T1/de
Publication of EP0179658A2 publication Critical patent/EP0179658A2/de
Publication of EP0179658A3 publication Critical patent/EP0179658A3/en
Application granted granted Critical
Publication of EP0179658B1 publication Critical patent/EP0179658B1/de
Expired legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F7/00—Other details of machines for making continuous webs of paper
    • D21F7/08—Felts
    • D21F7/12—Drying
    • 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
    • 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

Definitions

  • the present invention relates to a surge control system, in particular for use in a variable speed electric drive for a centrifugal exhauster such as that utilized in dewatering applications.
  • the vacuum pumps are sized for maximum demand vacuum conditions in the suction pipe when the felt is new.
  • the vacuum pump will normally run at its maximum speed with a new felt.
  • the fabric becomes less permeable and so requires a higher vacuum level for dewatering.
  • the vacuum level will automatically increase.
  • an object of the invention to provide an automatic surge control system for a variable speed drive centrifugal exhauster used in dewatering applications.
  • a surge control for dewatering press felts on a papermaking machine comprises of a suction pipe; a variable speed drive motor; a centrifugal exhauster driven by the variable speed drive motor and connected to the suction pipe to provide vacuum to a felt passing over a slot for dewatering thereof, and whereby as the felt permeability and air flow demand decrease, the drive motor increases the speed of the centrifugal exhauster up to a predetermined maximum speed; characterized by control means coupled to the centrifugal exhauster for determining when the predetermined maximum speed occurs, said control means being coupled to said drive motor for monitoring when a predetermined load on the drive motor occurs at which the centri-exhauster when operating at maximum speed will surge, and a surge valve for admitting air to the centrifugal exhauster, said control means being coupled to said surge valve and operative in signalling said valve to admit air to the centrifugal exhauster when said centrifugal
  • the invention provides a method of controlling surge in papermaking machines for dewatering press felts including a suction pipe, a surge valve, a variable speed drive motor, a centrifugal exhauster driven by the variable speed drive motor and connected to the suction pipe to provide vacuum to a felt passing over a slot for dewatering thereof, and whereby as the felt permeability and air flow demand decrease, the drive motor increases the speed of the centrifugal exhauster, the method including the step of limiting the speed of the exhauster to a predetermined maximum speed and being characterized by the steps of; determining when the predetermined maximum speed of the centrifugal exhauster occurs; monitoring when a predetermined load on the drive motor occurs at which the centrifugal exhauster when operating at maximum speed will surge; and opening the surge valve to admit air to the centrifugal exhauster when said centrifugal exhauster is operating at the predetermined maximum speed and the drive motor has a predetermined load thereon so as to prevent the centrifugal exhauster from going into surge.
  • Fig. 1 is a schematic view of a vacuum control system as part of a section of a papermaking machine
  • Fig. 2 is a representative performance curve for a particular variable speed centrifugal exhauster.
  • the depicted portion 10 is of a well known type of papermaking machine which utilizes one or more suction pipes 12 for dewatering a press felt 14 or similar fabric.
  • suction pipes 12 for dewatering a press felt 14 or similar fabric.
  • US Patent No. 4,329,201 This is a common arrangement at the press section of the papermaking machine.
  • the typical suction pipes 12 include a hollow conduit 16 with a slot 18 forming an opening in its upper end over which the felt or fabric passes.
  • An exit conduit 20 passes to a conventional type of liquid and gas separator 22.
  • the separator 22 has a bottom exit for passage of separated liquid into a seal pit through a drop leg.
  • the separator 22 is in turn connected by conduit 24 to a vacuum pump 26, which is a centrifugal exhauster type.
  • a centrifugal exhauster may be of the type manufactured by Hoffman Air & Filtration Systems, a division of Clarkson Industries, Inc., PO Box 214, Eastwood Station, Syracuse, New York 13206.
  • Publication CBE-378 entitled "Centrifugal Blowers and Exhausters” put out by the aforenoted company.
  • a relief or surge valve 28 is positioned between the separator 22 and the exhauster 26 for vacuum and surge release purposes when needed. Silencers 32 and 34 are also provided.
  • the drive means 38 is a variable speed drive AC motor and may be of the type manufactured for example by Reliance Electric, 24703 Eucled Avenue, Cleveland, Ohio 44117 (A-C VS Drives; Duty Master-XE; AC Motors; and Max Pak plus); Toshiba Corporation 13-12 Mita 3 chrome, Minato-ku, Tokyo, Japan (MF Pack); Toshiba/Houston International Corporation, 13131 West Little York Road, Houston, Texas 77041 (ESP-130 series); Parametics, Orange, Connecticut.
  • the drive means 38 is coupled to a control panel 40 via connection 42 which may be electrical wiring.
  • the control panel 40 is coupled through connection 44 to surge valve 28 which in turn is coupled to conduit 24.
  • variable speed motor 38 speeds up as the felt permeability decreases thereby producing a higher vacuum at the suction pipe 12. Since the air flow through the felt is less, a higher vacuum at a lower air flow is possible by speeding up the exhauster while maintaining the same torque or drive power.
  • the system allows the exhauster to run at a variable speed to meet the required vacuum at the suction pipe to dewater a felt as it goes from new to old rather than throttling the air flow by turning down a valve as was done heretofore with constant speed exhausters.
  • Such a drive system also allows for the automatic adjustment of the exhauster during dewatering of multigrade webs for example light webs at slower speeds; and heavier webs at higher speeds.
  • the speed of the motor can be varied by varying the AC frequency delivered to the motor. This is a standard feature in many of the models of AC motors mentioned previously.
  • the operation of the drive motor 38 may be automatically controlled using a feedback loop arrangement regulating the frequency and/or current at the desired level.
  • the maximum speed of the motor is limited, to prevent overloading, by setting the maximum current (or current frequency) or by setting the maximum speed.
  • the voids in a felt fabric fill and it becomes less permeable (volume per minute flow of air decreases) with use, causing the vacuum level required for dewatering to rise.
  • the power increases as the vacuum level increases with use of the felt fabric.
  • the centrifugal exhauster 26 of Fig. 1 as the air flow decreases through the fabric with use, the power decreases.
  • Fig. 2 shows the performance curve for a variable speed exhauster and shows that, as the speed of the exhauster varies, so do the surge points. Since the power (kW) at the surge point varies at different rpms, as shown, a monitoring thereof is insufficient since there would be no specific signal which would indicate that the exhauster is entering a surge region.
  • control panel 40 signals the surge valve 28 to open and admit air to the exhauster 26 to prevent further reduction of air flow, so preventing the exhauster 26 from going into surge.
  • the control panel 40 senses an exhauster speed of 4200 rpm and monitors a power output of the variable drive motor 38 that is less than or equal to 59.7 kW (80 hp), it signals the surge valve 28 to permit air to be admitted to the exhauster so preventing a further reduction of air flow and the exhauster from going into surge.
  • the control panel signals the surge valve to close.
  • the dead band control region which in this case is the range 59.7 to 61.2 kW (80 to 82 hp), is used to prevent valve "hunting".
  • the maximum speed will vary upon the particular exhauster involved and the application.
  • the performance curve for the particular maximum speed is readily available from the manufacturer.
  • Rotational sensors for monitoring the speed of the exhausters are also available along with the monitor for the power output of the variable drive engine.
  • the current demand of the motor or frequency can be monitored instead of power output.
  • the speed of the exhauster 26 automatically increases as the air flow demand (ie, at the suction slot 18) decreases due to a change in felt permeability. If for example, the suction slot 18 was completely shut off, the exhauster 26 would automatically speed up to its maximum speed. With such an arrangement, it is determined that the exhauster 26 cannot go into surge until after it reaches its maximum speed setting. Therefore, surge need only be controlled at the maximum speed of the exhauster.
  • the control panel 40 senses when the exhauster is running at maximum speed and when the power (kW), current draw (amp) or frequency drops below a predetermined amount. Thereupon, the control panel 40 causes the surge valve 28 to open to admit air to the exhauster 26 to prevent further reduction of air flow, thus preventing the exhauster from going into surge.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Paper (AREA)
  • Control Of Positive-Displacement Air Blowers (AREA)
  • Control Of Eletrric Generators (AREA)
  • Centrifugal Separators (AREA)
  • Drying Of Solid Materials (AREA)
  • Filtration Of Liquid (AREA)
  • Buffer Packaging (AREA)
  • Medicines Containing Plant Substances (AREA)
  • Measuring Volume Flow (AREA)
  • Making Paper Articles (AREA)
  • Controlling Rewinding, Feeding, Winding, Or Abnormalities Of Webs (AREA)

Claims (5)

1. Ein Pumpschwingungsüberwachungssystem für die Entwässerung von Pressfilzen auf einer Papierherstellungsmaschine, das ein Saugrohr (12), einen Antriebsmotor (38) variabler Drehzahl, einen Zentrifugalexhaustor (26) umfaßt, angetrieben durch den Antriebsmotor variabler Drehzahl und angeschlossen an das Saugrohr zum Einwirkenlassen von Vakuum auf einen Filz (14), der über einen Schlitz (18) für seine Entwässerung läuft, und wobei mit abnehmender Filzpermeabilität und Luftströmungsanforderung der Antriebsmotor die Drehzahl des Zentrifugalexhaustors bis zu einer vorbestimmten Maximaldrehzahl steigen läßt, gekennzeichnet durch Überwachungsmittel (40), angekoppelt an den Zentrifugalexhaustor für die Bestimmung, wann die vorbestimmte Maximaldrehzahl auftritt, wobei die genannten Überwachungsmittel an den genannten Antriebsmotor angekoppelt sind für die Überwachung, wann eine vorbestimmte Belastung an dem Antriebsmotor auftritt, bei welcher der Zentrifugalexhaustor, wenn er mit Maximaldrehzahl läuft, in Pumpschwingungen geraten würde, und ein Pumpschwingungsventil (28) für den Lufteinlaß zum Zentrifugalexhaustor, wobei die genannten Überwachungsmittel an das genannte Pumpschwingungsventil angekoppelt sind und ausgebildet sind, dem genannten Ventil zu signalisieren, Luft zu dem Zentrifugalexhaustor einzulassen, wenn der genannte Zentrifugalexhaustor mit der vorbestimmten Maximaldrehzahl arbeitet und der Antriebsmotor eine vorbestimmte Belastung aufweist, um so zu verhindern, daß der Zentrifugalexhaustor in Pumpschwingungen gerät.
2. Ein System nach Anspruch 1, bei dem der genannte Antriebsmotor variabler Drehzahl ein Wechselstrommotor ist und die genannten Überwachungsmittel die Belastung desselben überwachen durch Überwachen des Strombedarfs oder der Frequenz oder der Ausgangsleistung des Motors.
3. Eine Papierherstellmaschine mit einem System nach Anspruch 1 oder 2, wobei das System zur Entwässerung eines Pressfilzes angeordnet ist.
4. Ein Verfahren der Überwachung von Pumpschwingungen in einer Papierherstellungsmaschine für die Entwässerung von Pressfilzen, das ein Saugrohr (12), ein Pumpschwingungsventil (28), einen Antriebsmotor (38) variabler Drehzahl, einen Zentrifugalexhaustor (26) umfaßt, angetrieben durch den Antriebsmotor variabler Drehzahl und angeschlossen an das Saugrohr zum Einwirkenlassen von Vakuum auf einen Filz (14), der über einen Schlitz (18) für seine Entwässerung läuft und wobei mit abnehmender Filzpermeabilität und Luftströmungsanforderung der Antriebsmotor die Drehzahl des Zentrifugalexhaustors ansteigen läßt, welches Verfahren den Schritt der Begrenzung der Drehzahl des Exhaustors auf eine vorbestimmte Maximaldrehzahl umfaßt und gekennzeichnet durch die Schritte ist: Bestimmen, wann die vorbestimmte Maximaldrehzahl des Zentrifugalexhaustors auftritt, Überwachen, wann eine vorbestimmte Belastung auf dem Antriebsmotor auftritt, bei welcher der Zentrifugalexhaustor, wenn er mit Maximaldrehzahl läuft, in Pumpschwingungen geraten würde, und Öffnen des Pumpschwingungsventils für den Zulaß von Luft zu dem Zentrifugalexhaustor, wenn der genannte Zentrifugalexhaustor mit der vorbestimmten Maximaldrehzahl läuft und der Antriebsmotor eine vorbestimmte Belastung aufweist, um so zu verhindern, daß der Zentrifugalexhaustor in Pumpschwingungen gerät.
5. Ein Verfahren nach Anspruch 4, das die Schritte umfaßt der Bereitstellung eines Wechselstrommotors als Antriebsmotor und Überwachung von dessen Belastung durch Überwachen des Strombedarfs oder der Frequenz oder der Ausgangsleistung des Antriebsmotors.
EP85307666A 1984-10-26 1985-10-24 Vakuumüberwachungssystem Expired EP0179658B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85307666T ATE43377T1 (de) 1984-10-26 1985-10-24 Vakuumueberwachungssystem.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US66502684A 1984-10-26 1984-10-26
US665026 1984-10-26

Publications (3)

Publication Number Publication Date
EP0179658A2 EP0179658A2 (de) 1986-04-30
EP0179658A3 EP0179658A3 (en) 1987-01-28
EP0179658B1 true EP0179658B1 (de) 1989-05-24

Family

ID=24668408

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85307666A Expired EP0179658B1 (de) 1984-10-26 1985-10-24 Vakuumüberwachungssystem

Country Status (10)

Country Link
EP (1) EP0179658B1 (de)
JP (1) JPS61108790A (de)
KR (1) KR920000753B1 (de)
AT (1) ATE43377T1 (de)
AU (1) AU570120B2 (de)
CA (1) CA1251673A (de)
DE (1) DE3570470D1 (de)
FI (1) FI81147C (de)
NO (1) NO167219C (de)
ZA (1) ZA854989B (de)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI125258B (fi) * 2010-07-19 2015-08-14 Runtech Systems Oy Menetelmä pyörimisnopeussäädetyn alipainekeskipakopuhaltimen ohjaamiseksi
US8961149B2 (en) 2010-07-19 2015-02-24 Runtech Systems Oy Method for controlling a regulated-rotation-speed low-pressure centrifugal fan
CN102337558B (zh) * 2011-11-03 2013-12-11 北京化工大学 一种离子膜电解槽的氧气扩散电极的安装及密封方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4734896U (de) * 1971-05-08 1972-12-18
US4329201A (en) * 1979-12-06 1982-05-11 Albany International Corp. Constant vacuum felt dewatering system
US4308077A (en) * 1979-12-06 1981-12-29 Albany International Corp. Constant flow felt dewatering system
US4398996A (en) * 1981-06-19 1983-08-16 Albany International Corp. Vacuum control system and method for dewatering fabrics
US4493608A (en) * 1982-12-27 1985-01-15 General Electric Company Surge control in compressor

Also Published As

Publication number Publication date
ZA854989B (en) 1986-05-28
NO854284L (no) 1986-04-28
FI852589L (fi) 1986-04-27
KR920000753B1 (ko) 1992-01-21
NO167219C (no) 1991-10-16
CA1251673A (en) 1989-03-28
FI81147B (fi) 1990-05-31
FI852589A0 (fi) 1985-06-28
EP0179658A3 (en) 1987-01-28
FI81147C (fi) 1990-09-10
AU570120B2 (en) 1988-03-03
NO167219B (no) 1991-07-08
JPS61108790A (ja) 1986-05-27
JPH032992B2 (de) 1991-01-17
ATE43377T1 (de) 1989-06-15
EP0179658A2 (de) 1986-04-30
KR860003385A (ko) 1986-05-23
AU4389585A (en) 1986-05-01
DE3570470D1 (en) 1989-06-29

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