[go: up one dir, main page]

US3898124A - Automatic control of a continuous digester, including level, concentration, and flow meters - Google Patents

Automatic control of a continuous digester, including level, concentration, and flow meters Download PDF

Info

Publication number
US3898124A
US3898124A US468061A US46806174A US3898124A US 3898124 A US3898124 A US 3898124A US 468061 A US468061 A US 468061A US 46806174 A US46806174 A US 46806174A US 3898124 A US3898124 A US 3898124A
Authority
US
United States
Prior art keywords
digester
pulp
outflow
chip
concentration
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
US468061A
Inventor
Torbjorn Olson
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.)
ABB Norden Holding AB
Original Assignee
ASEA 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
Priority claimed from SE14737/71A external-priority patent/SE362909B/xx
Application filed by ASEA AB filed Critical ASEA AB
Priority to US468061A priority Critical patent/US3898124A/en
Application granted granted Critical
Publication of US3898124A publication Critical patent/US3898124A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/22—Other features of pulping processes
    • D21C3/228—Automation of the pulping processes

Definitions

  • ABSTRACT In a continuous digester which has a boiler with a rotatable bottom scraper and a chip and lye inflow at the top as well as a wash inflow into and a pulp outflow from the boiler.
  • concentration at the pulp outflow is measured and is used to control the rotation of the scraper so as to maintain a constant concentration of the outgoing pulp.
  • a flow meter at the pulp outflow controls a throttle valve to regulate the outflow.
  • the liquid in the top of the digester is measured and is used to control the devices which feed chips to the digester.
  • Measurement of the pressure in the digester is used to control the flow of black liquor at the chip and lye inflow.
  • the chips are fed in by a chip screw which in turn is fed by a segmental wheel. and the speeds of the chip screw and segmental wheel are maintained proportional to each other.
  • the present invention relates to an arrangement in a continuous digester. for example a continuous sulphate digester.
  • a continuous digester for example a continuous sulphate digester.
  • Such an arrangement comprises a boiler with a rotatable bottom scraper or similar feeding-outdevice at the bottom and with chip and lye inflow at the boiler and wash liquor inflow to and pulp outflow from said boiler at the bottom.
  • Chips are supplied in a constant flow along with white liquor and black liquor. Wash liquor is also supplied in variable amounts. controlled by a throttle valve which is regulated by the pressure in the digester.
  • the outgoing plug from the digester has a varying concentration which it is difficult to measure so that it is difficult to obtain a constant concentration in the output.
  • This invention is intended as a solution to these and other related problems and is characterised in that a concentration meter is arranged at the pulp outflow. the output signal of which is arranged to control the speed of the bottom scraper. in order to obtain a constant concentration for the outgoing pulp. and that a flow meter. known per se. is arranged at the pulp out flow. the output signal of which is transmitted over a regulator to a control device for a throttle valve at the pulp outflow. Since both the wash liquor (water black liquor) and the feedingout of pulp are constantly regulated. no disturbances occur here from the bottom of the digester to the digester top and a stable control process is obtained.
  • the digester pressure is measured with a pressure measuring device.
  • the output signal of which is arranged to control the black liquor flow to the inflow at the digester top.
  • FIG. I shows diagrammatically the system utilized in the prior art
  • FIG. 2 shows a diagrammatic system embodying the invention
  • FIG. 3 shows a chip feeding device
  • Chips are supplied in a constant flow at I3, white liquor at 14 and a constant flow of black liquor at IS. in another part of the digester. wash liquor is supplied in varying degree (at 16). the pressure in the digester being measured at 17, and the output signal of the measuring device 17 controlling a throttle valve 18 in the wash liquo'r pipe I6.
  • the outgoing pulp from the digester (at 19) has a varying concentration. and since it has been difficult up to now to measure this concentration it has also be difficult to obtain a constant concentration in this outflow I9.
  • the pressure regulating circuit 16-18 which is placed at the digester bottom. is supplied. as mentioned before, with a varying amount of wash liquor depending on the digester pressure (at 17).
  • FIG. 2 a digester 23 having a rotatable bottom scraper 24 with variable speed is shown.
  • the variable speed of the scraper is obtained from the drive device over a variable gear. and the drive device can also be speed controlled.
  • Element 25 is a regulator for gearing or speed control.
  • a concentration meter 27 is placed in the outflow pipe for finished pulp 26, for example a concentration meter of the kind manufactured by A B KALLE REGULATOR.
  • a customary flow meter 28 is also placed in the outflow pipe. said flow meter controlling a throttle valve 29 for the pulp flow.
  • Wash liquor water black liquor
  • a pressure meter 31 at the boiling zone of the di gester 23 measures the digester pressure. and its output signals are transmitted to a control valve 32 for black liquor. Chips are supplied through a feeding device 34 and white liquor is supplied at 33.
  • FIG. 3 shows the segmental wheel 4] and the cooking vessel 36 with a chip screw 37 driven by a motor 38. Chips are fed from the screw to a chip chute 39. and a mixture of chips and lye is fed through a highpressure crock 40 to the digester top. where white and black liquor are further fed, according to FIG. 2.
  • Part 34 in FIG. 2 corresponds to the elements shown in FIG. 3.
  • the control is made with the motor 38 or a gear close to the motor.
  • the speed of the chip screw 37 is altered proportionally to the speed of the cell wheel 4]. In the space containing the chip screw 37, that is the cooking vessel, the chips stay for about minutes. and if an attempt were made to control the flow to the digester by controlling the segmental wheel 41, the through transport delay would be great. This is now avoided by controlling the speed of the chip screw.
  • a level meter is arranged to control the chip feeding. so that a constant chip level is easily obtained in the digester. while compensation for varying chip moisture content is also obtained through the black liquor control.
  • the above-mentioned arrangement is also applicable in the case of continuous digesters with a separate impregnation zone (the impregnation zone is the part which corresponds to the upper part of the digester described).
  • a continuous digester comprising a boiler with a rotatable bottom scraper with a drive motor. chips and lye inflow at the top of the boiler. wash liquor inflow means to the bottom ofthe boiler. and the pulp outflow means from the bottom ofthe boiler, said digester comprising:
  • a level meter for measuring the liquid level in the top of the digester, chip feeding means connected to the chip inflow means. and means responsive to the output signal of said level meter to control the Chip feeding means;
  • a concentration meter in the pulp outflow means b. a concentration meter in the pulp outflow means.
  • means for controlling the drive motor including means responsive to a signal from the concentration meter to regulate the speed of the scraper to maintain a predetermined concentration of the outgoing pulp;
  • a flow meter and a throttle valve in the pulp outflow means and means responsive to the flow meter for controlling the throttle valve to obtain a predetermined outflow for the outgoing pulp.
  • a continuous digester according to claim 1 having the concentration and flow meters arranged in series in the pulp outflow means.
  • a continuous digester having a pressure measuring device associated with the digester for measuring its pressure. and means responsive to the output signal of said pressure measuring device for controlling the flow of black liquor at the chip and lye inflow means.
  • a continuous digester in which said means for controlling the throttle valve includes means to maintain a constant outflow for the outgoing pulp.

Landscapes

  • Paper (AREA)

Abstract

In a continuous digester which has a boiler with a rotatable bottom scraper and a chip and lye inflow at the top as well as a wash inflow into and a pulp outflow from the boiler, the concentration at the pulp outflow is measured and is used to control the rotation of the scraper so as to maintain a constant concentration of the outgoing pulp. A flow meter at the pulp outflow controls a throttle valve to regulate the outflow. The liquid in the top of the digester is measured and is used to control the devices which feed chips to the digester. Measurement of the pressure in the digester is used to control the flow of black liquor at the chip and lye inflow. The chips are fed in by a chip screw which in turn is fed by a segmental wheel, and the speeds of the chip screw and segmental wheel are maintained proportional to each other.

Description

United States Patent Olson Aug. 5, 1975 [5 1 AUTOMATIC CONTROL OF A 3.097.987 7/1963 Sloman l62/l7 CONTINUOUS DIGESTER INCLUDING 3.429.773 2/l969 Richter .1 l62/237 LEVEL, CONCENTRATION, AND FLOW FOREIGN PATENTS OR APPLICATIONS METERS 188.115 3/!964 Sweden 162/237 [75] Inventor: Torbjorn Olson, Vusteras, Sweden [73] Assignee: Allmanna Svenska Elektriska Aktiebolaget, Vasteras. Sweden [22] Filed: May 7, I974 [2]] Appl. No: 468,061
Related U.S. Application Data [63] Continuation of Ser. No. 301.743. Oct. 30. I972.
abandoned.
[30] Foreign Application Priority Data Nov. 18, l97| Sweden [4737/71 [52] U.S. Cl. .1 162/238; 162/243; 162/263 [5 l] Int. Cl. D21c 7/12 [58] Field of Search l62/238, 237. 243, 263, l62/l 7 {56] References Cited UNITED STATES PATENTS 2.938.824 5/l960 Richter .1 162/237 X Primary ExaminerS. Leon Bashore Assistant ExuminerRichard V. Fisher (5 7] ABSTRACT In a continuous digester which has a boiler with a rotatable bottom scraper and a chip and lye inflow at the top as well as a wash inflow into and a pulp outflow from the boiler. the concentration at the pulp outflow is measured and is used to control the rotation of the scraper so as to maintain a constant concentration of the outgoing pulp. A flow meter at the pulp outflow controls a throttle valve to regulate the outflow. The liquid in the top of the digester is measured and is used to control the devices which feed chips to the digester. Measurement of the pressure in the digester is used to control the flow of black liquor at the chip and lye inflow. The chips are fed in by a chip screw which in turn is fed by a segmental wheel. and the speeds of the chip screw and segmental wheel are maintained proportional to each other.
4 Claims, 3 Drawing Figures PATENTED AUG 5197s HlLlJf/JHJ.
70 13/655 T5, TOP
AUTOMATIC CONTROL OF A CONTINUOUS DIGESTER. INCLUDING LEVEL, CONCENTRATION, AND FLOW METERS DESCRIPTION OF THE PREFERRED EMBODIMENTS In continuous digesters used up to now. such as sul- This is a continuation of application Ser. No. 301,743 5 phate digEsters (FIG- Chips mixed with white liquor filed Oct. 30. I972, now abandoned.
BACKGROUND OF THE INVENTION I. Field of the Invention The present invention relates to an arrangement in a continuous digester. for example a continuous sulphate digester. Such an arrangement comprises a boiler with a rotatable bottom scraper or similar feeding-outdevice at the bottom and with chip and lye inflow at the boiler and wash liquor inflow to and pulp outflow from said boiler at the bottom.
2. The Prior Art In continuous digesters used heretofore such as sulphate digesters. chips mixed with white liquor and black liquor. that is. white liquor plus compounds released from pulp wood, have been led to a boiler from an inflow. During stationary operation it is difficult to measure the moisture content in the incoming chip flow. Chips are supplied in a constant flow along with white liquor and black liquor. Wash liquor is also supplied in variable amounts. controlled by a throttle valve which is regulated by the pressure in the digester.
The outgoing plug from the digester has a varying concentration which it is difficult to measure so that it is difficult to obtain a constant concentration in the output.
SUMMARY OF THE INVENTION This invention is intended as a solution to these and other related problems and is characterised in that a concentration meter is arranged at the pulp outflow. the output signal of which is arranged to control the speed of the bottom scraper. in order to obtain a constant concentration for the outgoing pulp. and that a flow meter. known per se. is arranged at the pulp out flow. the output signal of which is transmitted over a regulator to a control device for a throttle valve at the pulp outflow. Since both the wash liquor (water black liquor) and the feedingout of pulp are constantly regulated. no disturbances occur here from the bottom of the digester to the digester top and a stable control process is obtained.
In a preferred embodiment, the digester pressure is measured with a pressure measuring device. the output signal of which is arranged to control the black liquor flow to the inflow at the digester top. In this way, it has been found that an automatic compensation is obtained of the varying liquid flow which derives its origin from varying chip moisture content. and thus this previously awkward factor of uncertainty has been compensated for.
BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:
FIG. I shows diagrammatically the system utilized in the prior art;
FIG. 2 shows a diagrammatic system embodying the invention; and
FIG. 3 shows a chip feeding device.
(Na OH Na ,S) and black liquor, that is. white liquor plus compounds released from pulp wood, have been led to a boiler II in an inflow. During stationary operation it is difficult to measure the moisture content in the incoming chip flow (at I2). Chips are supplied in a constant flow at I3, white liquor at 14 and a constant flow of black liquor at IS. in another part of the digester. wash liquor is supplied in varying degree (at 16). the pressure in the digester being measured at 17, and the output signal of the measuring device 17 controlling a throttle valve 18 in the wash liquo'r pipe I6.
There are also other inflows to the digester. but they have been omitted since they are of no importance to the object of the invention or the prior art.
The outgoing pulp from the digester (at 19) has a varying concentration. and since it has been difficult up to now to measure this concentration it has also be difficult to obtain a constant concentration in this outflow I9. The pressure regulating circuit 16-18, which is placed at the digester bottom. is supplied. as mentioned before, with a varying amount of wash liquor depending on the digester pressure (at 17).
Attempts are made to keep the amount of chips to the digester (at 13) and the amount of pulp from the digester (at I9) constant with the help of flow regulating devices. Attempts have been made to keep the chip level in the digester lI constant with the help ofa rotatable bottom scraper 20, the number of revolutions of which can be varied. The speed of the bottom scraper 20 affects the concentration of the outgoing pulp. The scraper 20 is driven slowly by means of a motor (not shown). and the speed of the scraper 20 can be varied. either by means of an intermediate gear or by means of speed control on the motor. The level is measured with a level meter 2I at the upper part of the digester II.
This method of trying to keep the concentration of the outgoing pulp constant does not work very well because of the dynamic properties of the digester. and in spite of the fact that the flow in measured (at 22) and the amount of pulp from the digester is controlled. It takes 7-12 minutes for a change in the speed of the bottom scraper to manifest itself in a changed level at the top of the digester, and therefore this regulating circuit has less satisfactory properties with inferior fluid balance as a result. Because of the inferior fluid balance in the digester II, an up-stream of hot liquor occurs regularly from the boiling zone 23 and upwards, and this disturbs the process and deteriorates the final product.
In FIG. 2 a digester 23 having a rotatable bottom scraper 24 with variable speed is shown. The variable speed of the scraper is obtained from the drive device over a variable gear. and the drive device can also be speed controlled. Element 25 is a regulator for gearing or speed control. A concentration meter 27 is placed in the outflow pipe for finished pulp 26, for example a concentration meter of the kind manufactured by A B KALLE REGULATOR. A customary flow meter 28 is also placed in the outflow pipe. said flow meter controlling a throttle valve 29 for the pulp flow. Wash liquor (water black liquor) is supplied in constant quantity at the lower part of the digester 23 (at 30).
A pressure meter 31 at the boiling zone of the di gester 23 measures the digester pressure. and its output signals are transmitted to a control valve 32 for black liquor. Chips are supplied through a feeding device 34 and white liquor is supplied at 33.
FIG. 3 shows the segmental wheel 4] and the cooking vessel 36 with a chip screw 37 driven by a motor 38. Chips are fed from the screw to a chip chute 39. and a mixture of chips and lye is fed through a highpressure crock 40 to the digester top. where white and black liquor are further fed, according to FIG. 2. Part 34 in FIG. 2 corresponds to the elements shown in FIG. 3. The control is made with the motor 38 or a gear close to the motor. The speed of the chip screw 37 is altered proportionally to the speed of the cell wheel 4]. In the space containing the chip screw 37, that is the cooking vessel, the chips stay for about minutes. and if an attempt were made to control the flow to the digester by controlling the segmental wheel 41, the through transport delay would be great. This is now avoided by controlling the speed of the chip screw.
A level meter is arranged to control the chip feeding. so that a constant chip level is easily obtained in the digester. while compensation for varying chip moisture content is also obtained through the black liquor control.
The above-mentioned arrangement is also applicable in the case of continuous digesters with a separate impregnation zone (the impregnation zone is the part which corresponds to the upper part of the digester described).
The invention may be varied in many ways within the scope of the following claims.
I claim:
I. A continuous digester comprising a boiler with a rotatable bottom scraper with a drive motor. chips and lye inflow at the top of the boiler. wash liquor inflow means to the bottom ofthe boiler. and the pulp outflow means from the bottom ofthe boiler, said digester comprising:
a. a level meter for measuring the liquid level in the top of the digester, chip feeding means connected to the chip inflow means. and means responsive to the output signal of said level meter to control the Chip feeding means;
b. a concentration meter in the pulp outflow means. means for controlling the drive motor. said motor controlling means including means responsive to a signal from the concentration meter to regulate the speed of the scraper to maintain a predetermined concentration of the outgoing pulp; and
c. a flow meter and a throttle valve in the pulp outflow means, and means responsive to the flow meter for controlling the throttle valve to obtain a predetermined outflow for the outgoing pulp.
2. A continuous digester according to claim 1, having the concentration and flow meters arranged in series in the pulp outflow means.
3. A continuous digester according to claim I, having a pressure measuring device associated with the digester for measuring its pressure. and means responsive to the output signal of said pressure measuring device for controlling the flow of black liquor at the chip and lye inflow means.
4. A continuous digester according to claim I, in which said means for controlling the throttle valve includes means to maintain a constant outflow for the outgoing pulp.

Claims (4)

1. A CONTINUOUS DIGESTER COMPRISING A BOILER WITH A ROTATABLE BOTTOM SCRAPER WITH A DRIVE MOTOR CHIPS AND LYE INFLOW AT THE TOP OF THE BOILER WASH LIQUOR INFLOW MEANS TO THE BOTTOM OF THE BOILER AND THE PULP OUTFLOW MEANS FROM THE BOTTOM OF THE BOILER SAID DIEGESTER COMPRISING: A. A LEVEL METER FOR MEASURING THE LIQUID LEVEL IN THE TOP OF THE DIGESTER CHIP FEEDING MEANS CONNECTED TO THE CHIP INFLOW MEANS AND MEANS RESPONSIVE TO THE OUTPUT SIGNAL OF SAID LEVEL METER TO CONTROL THE CHIP FEEDING MEANS, B. A CONCENTRATION METER IN THE PULP OUTFLOW MEANS MEANS FOR CONTROLLING THE DRIVE MOTOR SAID MOTOR CONTROLLING MEANS INCLUDING MEANS RESPONSIVE TO A SIGNAL FROM THE CONCENTRATION METER TO REGULATE THE SPEED OF THE SCRAPER TO MAINTAIN A PREDETERMINED CONCENTRATION OF THE OUTGOING PULP AND C. A FLOW METER AND A THROTTLE VALVE IN THE PULP OUTFLOW MEANS AND MEANS RESPONSIVE TO THE FLOW METER FOR CONTROLLING THE THROTTLE VALVE TO OBTAIN A PREDETERMINED OUTFLOW FOR THE OUTGOING PULP.
2. A continuous digester according to claim 1, having the concentration and flow meters arranged in series in the pulp outflow means.
3. A continuous digester according to claim 1, having a pressure measuring device associated with the digester for measuring its pressure, and means responsive to the output signal of said pressure measuring device for controlling the flow of black liquor at the chip and lye inflow means.
4. A continuous digester according to claim 1, in which said means for controlling the throttle valve includes means to maintain a constant outflow for the outgoing pulp.
US468061A 1971-11-18 1974-05-07 Automatic control of a continuous digester, including level, concentration, and flow meters Expired - Lifetime US3898124A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US468061A US3898124A (en) 1971-11-18 1974-05-07 Automatic control of a continuous digester, including level, concentration, and flow meters

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE14737/71A SE362909B (en) 1971-11-18 1971-11-18
US30174372A 1972-10-30 1972-10-30
US468061A US3898124A (en) 1971-11-18 1974-05-07 Automatic control of a continuous digester, including level, concentration, and flow meters

Publications (1)

Publication Number Publication Date
US3898124A true US3898124A (en) 1975-08-05

Family

ID=27354875

Family Applications (1)

Application Number Title Priority Date Filing Date
US468061A Expired - Lifetime US3898124A (en) 1971-11-18 1974-05-07 Automatic control of a continuous digester, including level, concentration, and flow meters

Country Status (1)

Country Link
US (1) US3898124A (en)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4135966A (en) * 1974-09-10 1979-01-23 Gloeersen Stig Method and device for equalizing the moisture content of porous material
US4141784A (en) * 1977-05-02 1979-02-27 Macmillan Bloedel Limited Method and apparatus for controlling wood chip digester level
US4753737A (en) * 1987-11-09 1988-06-28 Wesley Staples Recovery method for settled black liquor
US5266159A (en) * 1991-10-25 1993-11-30 Kamyr, Inc. Mass flow measurement, preferably for controlling chip feed to a digester
US5597446A (en) * 1992-01-31 1997-01-28 New Oji Paper Co., Ltd. Method of controlling a position of rotor in a high pressure feeder
EP0937813A3 (en) * 1994-08-18 1999-09-01 Ahlstrom Machinery, Inc. Enhancement in pulping with dissolved solids control
US6211470B1 (en) 1999-11-22 2001-04-03 Westvaco Corporation Height measurement apparatus for determining the volume/density of wood chips on a conveyor
US6339859B1 (en) * 1999-06-25 2002-01-22 Lewis D. Shackford Control system for a filtrate splitting device
US6393908B1 (en) * 2000-03-07 2002-05-28 Daniel A. Swain Outflow meter
US20120021102A1 (en) * 2010-07-21 2012-01-26 John Bean Technologies Corporation Apparatus and method for sensing the concentration of pulp in a concentrated pulp stream
US20120021098A1 (en) * 2010-07-21 2012-01-26 John Bean Technologies Corporation, Corporation of the State of Delaware Apparatus and method for sensing and controlling the concentration of pulp in a concentrated pulp stream
CN104878641A (en) * 2015-06-08 2015-09-02 无锡市羊尖盛裕机械配件厂 Automatic pulp concentration adjusting device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2938824A (en) * 1957-01-22 1960-05-31 Kamyr Ab Digestion apparatus and method
US3097987A (en) * 1960-02-08 1963-07-16 Ass Pulp & Paper Mills Continuous pulping process
US3429773A (en) * 1964-04-16 1969-02-25 Kamyr Ab Continuous cellulose digester with charging device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2938824A (en) * 1957-01-22 1960-05-31 Kamyr Ab Digestion apparatus and method
US3097987A (en) * 1960-02-08 1963-07-16 Ass Pulp & Paper Mills Continuous pulping process
US3429773A (en) * 1964-04-16 1969-02-25 Kamyr Ab Continuous cellulose digester with charging device

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4135966A (en) * 1974-09-10 1979-01-23 Gloeersen Stig Method and device for equalizing the moisture content of porous material
US4141784A (en) * 1977-05-02 1979-02-27 Macmillan Bloedel Limited Method and apparatus for controlling wood chip digester level
US4753737A (en) * 1987-11-09 1988-06-28 Wesley Staples Recovery method for settled black liquor
US5266159A (en) * 1991-10-25 1993-11-30 Kamyr, Inc. Mass flow measurement, preferably for controlling chip feed to a digester
US5597446A (en) * 1992-01-31 1997-01-28 New Oji Paper Co., Ltd. Method of controlling a position of rotor in a high pressure feeder
EP0937813A3 (en) * 1994-08-18 1999-09-01 Ahlstrom Machinery, Inc. Enhancement in pulping with dissolved solids control
US6339859B1 (en) * 1999-06-25 2002-01-22 Lewis D. Shackford Control system for a filtrate splitting device
US6211470B1 (en) 1999-11-22 2001-04-03 Westvaco Corporation Height measurement apparatus for determining the volume/density of wood chips on a conveyor
US6393908B1 (en) * 2000-03-07 2002-05-28 Daniel A. Swain Outflow meter
US20120021102A1 (en) * 2010-07-21 2012-01-26 John Bean Technologies Corporation Apparatus and method for sensing the concentration of pulp in a concentrated pulp stream
US20120021098A1 (en) * 2010-07-21 2012-01-26 John Bean Technologies Corporation, Corporation of the State of Delaware Apparatus and method for sensing and controlling the concentration of pulp in a concentrated pulp stream
US8820226B2 (en) * 2010-07-21 2014-09-02 John Bean Technologies Corporation Apparatus and method for sensing the concentration of pulp in a concentrated pulp stream
US8820225B2 (en) * 2010-07-21 2014-09-02 John Bean Technologies Corporation Apparatus and method for sensing and controlling the concentration of pulp in a concentrated pulp stream
CN104878641A (en) * 2015-06-08 2015-09-02 无锡市羊尖盛裕机械配件厂 Automatic pulp concentration adjusting device

Similar Documents

Publication Publication Date Title
US3898124A (en) Automatic control of a continuous digester, including level, concentration, and flow meters
US4840703A (en) Method for controlling an oxygen bleaching
US4419184A (en) Method for control of chemicals during gas treatment of suspensions
GB1241120A (en) A paper manufacturing system and a method of controlling the same
US4536253A (en) Process for controlling the properties of white liquor
US3271241A (en) Stock supply system for papermaking machines including control of stock consistency and stock flow
US3886034A (en) Process for determining the conditions needed in controllably obtaining sulfate pulp having a predetermined kappa number
US4878998A (en) Method for controlling peroxide bleaching in a plurality of bleaching stages
US3764463A (en) Method and apparatus for chromatic control of pulping process
US3322616A (en) Pulp digester control apparatus
US3816241A (en) Method and apparatus for feed-forward control of wood pulp refiners
US3486971A (en) Control of chlorine dioxide bleaching
US3096234A (en) Continuous digesting system
CN114326573B (en) Continuous slurry preparation method and system based on PLC system
US3272691A (en) Apparatus for continuously chlorinating pulp including automatic control of the degree of chlorination
US3846231A (en) Apparatus for determination of the magnitude of total specific energy absorbed by a sample of pulp stock
US4162933A (en) Exothermic heat as a means of determining the degree of delignification
SU770548A1 (en) Apparatus for automatic control of flotation process
US3926719A (en) Dry line controller
GB1024316A (en) Method of, and apparatus for, controlling a continuously operating distillation process
SU971966A1 (en) System for controlling an installation for continuous cooking of sulphate pulp
SU1535909A1 (en) Method of controlling the process of continuous digestion of sulfate pulp
SU438744A1 (en) Device for automatic regulation of the active alkalinity of the cooking solution
SU926131A1 (en) Method for automatically controlling process of continuous cooking of sulphate pulp
SU414337A1 (en) METHOD FOR AUTOMATIC REGULATION OF THE PERIODIC PROCESS OF SULFATE COOKING