CA2309635C - Method and device for continuous dosing - Google Patents

Method and device for continuous dosing Download PDF

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Publication number
CA2309635C
CA2309635C CA002309635A CA2309635A CA2309635C CA 2309635 C CA2309635 C CA 2309635C CA 002309635 A CA002309635 A CA 002309635A CA 2309635 A CA2309635 A CA 2309635A CA 2309635 C CA2309635 C CA 2309635C
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CA
Canada
Prior art keywords
rotary
metering
metering device
vane feeder
bulk material
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 - Lifetime
Application number
CA002309635A
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French (fr)
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CA2309635A1 (en
Inventor
Hans Wilhelm Hafner
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Pfister GmbH
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Pfister GmbH
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Publication date
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Publication of CA2309635A1 publication Critical patent/CA2309635A1/en
Application granted granted Critical
Publication of CA2309635C publication Critical patent/CA2309635C/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01GWEIGHING
    • G01G11/00Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers
    • G01G11/08Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers having means for controlling the rate of feed or discharge
    • G01G11/083Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers having means for controlling the rate of feed or discharge of the weight-belt or weigh-auger type

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Filling Or Emptying Of Bunkers, Hoppers, And Tanks (AREA)
  • Weight Measurement For Supplying Or Discharging Of Specified Amounts Of Material (AREA)
  • Air Transport Of Granular Materials (AREA)
  • External Artificial Organs (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
  • Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
  • Medicinal Preparation (AREA)

Abstract

The invention relates to a method and device for continuous dosing of bulk material allowing dosing and conveyance capacity to be improved, especially when there are substantial fluctuations in conveyor air flow. A cellular wheel sluice (4) disposed upstream from the dosing device (8) re-directs part of the bulk material to the container (2) when it moves in an upwards direction. The re-directing cells (7) of the cellular wheel sluice (4) leading towards the container (2) are preferably filled to approximately 30 % to improve tightness with respect to leaking air.

Description

21:57 4aCF PRTENT FIENER -~ 0016043319382 NUM485 D004 iption and apparatus for contianous metering ~' '~ This invention relates to a method and an apparatus for continuous metering of bulk ~,.: ,,, .
''i ;~..~ material from a container, with a rotary-vane feeder and a metering device following the rotary-vane t feeder.
Such a system for continuous feed of bulk material is known from DE 40 23 948 Al, ~t : ~1?~ ,' wherein a metering rotor scale according to DE 32 17 406 A1 or EP-A 0 198 956 is employed. This ~ i metering device following a bulk material feeder is connected downstream in a closed pneumatic (,, t tt..
~~:', conveyor path of a collecting device with a rotary-vane feeder. The bulk material mass contained ~l ,!: F ~E~~therein can accordingly be determined continuously and influence either the speed of rotation of the rotary-vane feeder or the total air-flow amount of the feed blower, so that the bulk material 1 throughput can be influenced by varying the amount of air supplied per unit time.
w,-,~,. ;~,:, ., , To effect the appropriate regulation of the desired mixing ratio or the desired feed amount ;.per unit time (feed rate) a computer-controlled, central metering control system is employed, such as is described in DE 32 17 406 A1 for example, wherein a weigh signal of the bin scale cells of the collecting device serves as an input signal and the speed of rotation of the metering rotor and if desired of the rotary-vane feeder for the bulk material feed is regulated.
This regulating system is also described in more detail in l:P-A 0 198 956 cited above, wherein the bulk material mass acting instantaneously in the metering rotor scale is detected, from which the bulk material mass throughput results through multiplicaeion by the angular velocity of the metering rotor. The weighing electronics store the instantaneous bulk material mass present on I the rotor weighing path (tneas~ring path), so that the rotor angular velocity can be varied shortly before the discharge of the hulk material into tht.pneumatic conveyor line, in accordance with the predetermined set-point feed rate. A relatively high metering accuracy results from this, which is SdYery well suited to metering powdered bulk material, for example in coat dust metering for cement rotary kilns or for metering gypsum or additives in flue gas purification.
i However it has to be recognised that, with certain conveyed materials, these bulk materials can tend to form bridges, depending on the degree of moisture, fluidisation, fineness, etc., so that random or strongly pulsating fluctuations in the mass flow can occur in the bulk material discharge.
These short-term mass flow fluctuations can be partially compensated by increased feed pressure, in particular even with large conveyor paths. However a greater leakage airstream to the container then oexurs, which can lead to disturbances in the bulk material feed and the feed rate. To some extent even in such systems for feeding bulk material, expensive leakage gas exhausts are thus necessary, 21: 57 KI~ PRTENT F I ENER -~ 0016043310382 NUM485 D005 so that the expense of construction is increased substantially.
Accordingly the invention is based on the object of providing a method and an apparatus for ' continuous metering of bulk material with which an improved tightness and large conveying capacity are obtained in a simple way.
This object is met by a method according to the featut~es of claim 1 and by an apparatus according to the features of claim 5.
By regulating the following metering device relative to the feed ratc of the preceding rotary-vane feeder or vice versa, an improved self sealing results from the partial return feed in the rotary-*~ ~ ' vane feeder, through the bulk material elevated in the returning cells, and accordingly a substantial ' reduction in the leakage gas flow into the metering system, so that a high metering or conveying !I;:. capacity is achicvcd. This is espcciaIly important for coal dust metering with large feed lengths and feed pressures.
Preferred embodiments are the subject matter of the dependent claims.
1 '''!*i~: Two embodiments will be described and explained in more detail below with reference to the drawings, in which:
Fig. 1 is a longitudinal sectional view through an apparatus for continuous bulk material metering with two rotary-vane feeders; and Fig. 2 shows a modified embodiment of the apparatus according to Fig. 1, wherein a metering rotor scale is used for the metering.
An apparatus 1 for continuous metering is shown in Fig. l, wherein the feed material to be metered in accordance with and adjustable set-point value, especially a pourable bulk material, is fed out of a silo or container 2 by,means of a discharge device 3 in the form of a rotary-vane feeder 4. The feed material passes into the rotary-vane feeder 4 and then into an intermediate container 5.
The rotary-vane feeder 4 is preferably formed as a sealed lock, which feeds bulk material out of the intermediate container 5 constantly filled with bulk material back up again and into the returning cells 7 here ort the right back to the container 2, as is shown in dots. The rotary-vane feeder 4 is driven by an electric motor b, which.is connected to a metering controller 10 for adjustment of the spend of rotation. The speed of rotation of the star wheel of the rotary-vane feeder 4 required for the "excess feed" is always (with otherwise equal dimensions) slightly higher than the speed of rotation of the lower rotary-vane feeder, which serves as a metering device.
However, in order to determine the mass flow of the rotary-vane feeder 4 the Speed of rotation can x150 be derived directly From the drive shaft or the power takon by the drive motor 6.
The rotary-vane feeder 4 shown here with a horizontal axis has the advantage of a relatively high metering accyracy, so that this form. of the rotary-vane feeder 4 a preferred.
However rotary-vane 21: 57 KKF Pf~TE~IT F t EVER ~ 0016043310382 NUM485 D006 _j-with vertical axes can also be used.
A metering device 8, again in the form of a rotary-vane feeder, is provided at the lower end r° y ", of the intermediate container 5, this device being driven by a motor 8a with a regulated speed of '~.,~.~. rotation and a blow-out line 9 opening into it. 1t is essential that the measured value sensor of the ~ "" ' rotary-vane feeder 4, i.e. a speed of rotation transducer or tacho-generator for example on the motor 6, is connected to the metering controller 10, which thus determines the instantaneous mass flow of the rotary-vane feeder 4 and relates it to the feed rate of the metering device 8, in order to adjust or vary its speed of rotation or angular velocity in accordance with the feed rate of the rotary-vane feeder 4, in the sense of an excess feed. Accordingly, if there is a deviation of the mass flow at the '~ rotary-vane feeder ~, the angular velocity of the rnetcring device 8 is reduced by the cotrtsponding value or the s of rotation of the -v a ;~, pad rotary an feeder 4 is Increased, tn order to keep the fill height '!,.I ' constant in the intermediate container 5.
It is of essential importance that the bulk material is skimmed offto the container 2 by the rotary-vane feeder 4 on account of the constant filling of the intermediate container 5, so that the at r~:vi ; least partlalIy filled, return feed cells ? substantially increase the tightness against leakage gas flows. Thus, it can be computed by the metering controller 10 what feed rate or speed of rotation of the rotary-vane feeder 4 is necessary to maintain the filling height and thus the return feed of about 30% of the bulk material. Depending on the angular velocity of the metering device 8 which is also measured (e.g. a tacho-generator, on_ the motor 8a) the appropriate feed rate of the rotary-vane feeder 4 arranged above the metering device 8 cxn ad,~usted or regulated, taking into account the filling height below the rotary-vane, feeder a. The metering controller 10 can thus regulate the speed of rotation of the rotary-vane feeder ~ at a!1 times taking into account the discharge rate of the meteuing device 8, so that a contictuous, deliberate return feed to the container 2 is possible through the upwardly running, return feed cells 7 here on the tight, and with this an improved tightness of the rotary-vane.fee~er 4 against leakage gas losses.
~., A modified embodiment of the apparatus ~ according to Fig,. 1 is shown in Fig. 2, wherein a metering rotor scale 8' (especially according to the state of the art recited in the introduction), with a l H ~ ' blow..out tine 9 and a weighing cell 1 l, is arranged below the rotary-vane feeder 4 as a metering device $. It should be noted that a horizontal lock (with a vertical axis) similar to the metering rotor 8' in Fig. 2 can be used instead of the lower rotary-vane feeder shown in Fig.
I . In an advantageous design, in order to keep the failing height constant below the rotary-vane feeder 4 its mass flow can be controlled or regulated to kbout 120 - 130% of the metering device 8, so that a return feed proportion of ?0 - 30% into the rotary-vane feeder 4 occurs., In a particularly simple design it is sufficient to branch, off a drive from the motor 8a and an associated drive of the metering device 8, 21:5? KKF PATENT FIENER -~ 0016043310382 NUM485 D007 in order to achieve synchronous regulation of the upper and lower rotary-vane feeders or the ': metering rotor. Naturally separate motors 6 and 8a can equally be provided and be controlled in ,~~ :. ~ , elccironically coupled manner by the metering controller 10.
S
In the modified embodiment of the apparatus 1 for continuous gravimetric metering N ,. Y ~, according to Fig. 2, a feed blower for the blow-out line 9 is also provided as a metering device 8 for ~' ~;j ~~ the metering and further feed, with a construction otherwise similar to Fig. 1. The drive motor of the ~_ . x~. ~~
''' feed blower (not shown) can also be connected to the metering controller 10, so that the feed rate ~: ;~~~4 ~~», ~ ~ ~ v~~~ in that the speed of rotation of the feed blower is increased or reduced briefly for Y
example.
Because of the deliberate "backing up" of the bulk material in the constantly f lied intermediate container S, which can also be substantially smaller, in the nature of a compensator or bladder, bulk material is deliberately skimmed off by the rotary-vane feeder 4 and constantly fed back, so that this bulk material serves for self sealing of the rotary-vane feeder 4 against leakage gas losses.

Claims (9)

WHAT IS CLAIMED IS:
1. ~A method of continuous metering of bulk material from a container (2) with a rotary-vane feeder (4) and a metering device (8) following the rotary-vane feeder (4), characterized in that the discharge rate of the metering device (8) relative to a speed of rotation of the preceding rotary-vane feeder (4) is adjusted to a smaller value, so that return feed from the rotary-vane feeder (4) to the container (2) takes place.
2. ~A method according to claim 1, characterized in that the adjustment or regulation is effected taking into account the filling state of an intermediate container (5) between the rotary-vane feeder (4) and the metering device (8).
3. ~A method according to claim 1 or 2, characterized in the discharge regulation of the metering device (8) is effected by altering the speed of rotation of the metering device (8).
4. ~A method according to claim 1 or 2, characterized in that, in the case of pneumatic feed, the discharge regulation of the metering device (8) is effected by altering the air amount and/or the air speed.
5. ~Apparatus for continuous metering of bulk material from the container with a rotary-vane feeder and a metering device following the rotary-vane feeder, characterized in that the rotary-vane feeder (4) is coupled to the metering device (8) via a metering controller (10) and the mass flow at the rotary-vane feeder (4) is greater then the discharge rate of the metering device (8) for partial return feed of the bulk material to the container (2).
6. ~Apparatus according to claim 5, characterized in that the metering device (8) is also formed as a rotary-vane feeder.
7. Apparatus according to claim 5, characterized in that the metering device (8) is formed as a metering rotor scale (8').
8. Apparatus according to claim 5, characterized in that the metering device (8) is formed as a horizontal lock.
9. Apparatus according to any of claims 5 to 8, characterized in that the return feed cells (7) of: the rotary-vane feeder (4) are filed to around 20 - 40%.
CA002309635A 1997-11-11 1998-11-11 Method and device for continuous dosing Expired - Lifetime CA2309635C (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19749873A DE19749873A1 (en) 1997-11-11 1997-11-11 Method and device for continuous dosing
DE19749873.6 1997-11-11
PCT/EP1998/007185 WO1999024795A1 (en) 1997-11-11 1998-11-11 Method and device for continuous dosing

Publications (2)

Publication Number Publication Date
CA2309635A1 CA2309635A1 (en) 1999-05-20
CA2309635C true CA2309635C (en) 2006-09-12

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CA002309635A Expired - Lifetime CA2309635C (en) 1997-11-11 1998-11-11 Method and device for continuous dosing

Country Status (8)

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EP (1) EP1031014B1 (en)
JP (1) JP3429494B2 (en)
CN (1) CN1139789C (en)
AT (1) ATE281644T1 (en)
AU (1) AU1561699A (en)
CA (1) CA2309635C (en)
DE (2) DE19749873A1 (en)
WO (1) WO1999024795A1 (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10317001B3 (en) * 2003-04-11 2004-11-25 Schenck Process Gmbh Device for continuous dosing and pneumatic conveying of free-flowing goods
DE10330376B4 (en) * 2003-07-04 2007-09-13 Pfister Gmbh Method and device for continuous, gravimetric dosing of flowable goods for combustion plants
JP4673259B2 (en) * 2006-06-30 2011-04-20 森永製菓株式会社 Process for producing granular food-containing food and production apparatus thereof
DE102006042914A1 (en) * 2006-09-13 2008-04-03 Schenck Process Gmbh Discharge device for bulk material from a bulk material container
CN102602711A (en) * 2012-03-06 2012-07-25 孙家鼎 Method for directly conveying coal ash in ash storage hopper of dust collectors
TWI550258B (en) * 2015-03-04 2016-09-21 技鼎股份有限公司 Material feeding device with real-time monitoring
CN108088537A (en) * 2017-11-15 2018-05-29 安徽省恒伟铋业有限公司 A kind of pulp pond metering device

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3626696A1 (en) * 1986-08-07 1988-02-11 Krupp Gmbh Cellular wheel sluice
CA2047929C (en) 1990-08-17 2001-08-14 Pfister Gmbh Gravimetric metering apparatus for pourable materials
DE4112268C1 (en) 1991-04-15 1992-03-12 Plasma-Technik Ag, Wohlen, Ch
DE59308647D1 (en) * 1993-03-10 1998-07-09 Pfister Gmbh Gravimetric dosing device for bulk goods
DE4443053A1 (en) * 1994-12-05 1996-06-13 Pfister Gmbh Method and device for continuous, gravimetric metering and mass flow determination of flowable goods

Also Published As

Publication number Publication date
CN1281549A (en) 2001-01-24
EP1031014A1 (en) 2000-08-30
ATE281644T1 (en) 2004-11-15
DE19749873A1 (en) 1999-05-12
WO1999024795A1 (en) 1999-05-20
DE59812227D1 (en) 2004-12-09
JP2001522989A (en) 2001-11-20
CN1139789C (en) 2004-02-25
CA2309635A1 (en) 1999-05-20
AU1561699A (en) 1999-05-31
EP1031014B1 (en) 2004-11-03
JP3429494B2 (en) 2003-07-22

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Effective date: 20181113