EP2569482A1 - Arrangement for degassing control - Google Patents

Arrangement for degassing control

Info

Publication number
EP2569482A1
EP2569482A1 EP11780884A EP11780884A EP2569482A1 EP 2569482 A1 EP2569482 A1 EP 2569482A1 EP 11780884 A EP11780884 A EP 11780884A EP 11780884 A EP11780884 A EP 11780884A EP 2569482 A1 EP2569482 A1 EP 2569482A1
Authority
EP
European Patent Office
Prior art keywords
pulp
conduit
pump
vacuum pump
housing
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Withdrawn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
EP11780884A
Other languages
German (de)
French (fr)
Inventor
Magnus Monsell
Peter Danielsson
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.)
Valmet Technologies Oy
Original Assignee
Metso Paper 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 Metso Paper Oy filed Critical Metso Paper Oy
Publication of EP2569482A1 publication Critical patent/EP2569482A1/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Withdrawn legal-status Critical Current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
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D15/00—Control, e.g. regulation, of pumps, pumping installations or systems
    • F04D15/0066—Control, e.g. regulation, of pumps, pumping installations or systems by changing the speed, e.g. of the driving engine
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
    • D21D5/00—Purification of the pulp suspension by mechanical means; Apparatus therefor
    • D21D5/26—De-aeration of paper stock
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D7/00—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts
    • F04D7/02—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type
    • F04D7/04—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type the fluids being viscous or non-homogenous
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D9/00—Priming; Preventing vapour lock
    • F04D9/001—Preventing vapour lock
    • F04D9/002—Preventing vapour lock by means in the very pump
    • F04D9/003—Preventing vapour lock by means in the very pump separating and removing the vapour

Definitions

  • the invention relates to an arrangement in a pulp pumping process, and in particular the invention relates to an arrangement for degassing control in a pulp pumping process where pulp is pumped and simultaneously degassed.
  • gas e.g. air
  • the gas tends to cumulate to bubbles that are
  • a vacuum pump is often connected via a conduit to the pulp pumping area, in order to create a sub pressure to evacuate the unwanted gas.
  • a problem with such arrangements is that pulp may follow the gas into the vacuum pump conduit and cause problems. Firstly, the pulp may completely or at least heavily impede the evacuation of gas such that the gas bubbles still may be accumulated in the pulp that is being pumped. Further, the pulp may get sucked into the vacuum pump and thereby compromise its function.
  • this problem is solved by arranging a means for supplying flushing water into the conduit, such that unwanted pulp is flushed away from the conduit.
  • this solution is not fully satisfactory as it results in an unwanted dilution of the pulp, or, if the flow of water is too small, an unsatisfactory removal of pulp from the conduit.
  • a compromise arises where the operator has to choose between an unwanted dilution, and an unsatisfactory removal of pulp from the conduit.
  • WO 03/014572 discloses a centrifugal pump for pumping a pulp suspension in which the amount of liquid added to the pulp may be reduced in that liquid is only added to the system upstream of the vacuum pump, whereas in conventional arrangements liquid has also been added downstream of the vacuum pump in order to guarantee its well function.
  • An object of the invention is to provide an improved arrangement and method for pumping pulp, which eliminate or reduce the problems of the prior art cited above, and which allows better control of the evacuation of gas from the pulp pumping chamber.
  • the invention relates to an arrangement for pumping pulp, which arrangement comprises a housing in which a pulp pump for pumping pulp is arranged, wherein a vacuum pump for degassing the pulp inside the housing is connected via a conduit to a gas outlet in the housing.
  • a control unit is arranged to control the pump speed of the vacuum pump and the control unit is connected to a sensor that is arranged in the conduit for detecting the presence of pulp in the conduit, wherein the control unit is arranged to lower the pump speed of the vacuum pump if pulp is detected in the conduit.
  • the invention relates to a method of pumping pulp by means of a pulp pump located inside a housing, which method comprises: degassing the pulp that is being pumped inside the housing by means of a vacuum pump, which is connected via a conduit to said housing.
  • the method further comprises: sensing if pulp is present in the conduit, indicating to a control unit if pulp is present in the conduit, and controlling the vacuum pump in response to the indication received by the control unit.
  • control unit is arranged to lower the pump speed, i.e. the rotation speed of the vacuum pump if pulp is detected in the conduit.
  • the sensing of pulp comprises the step of measuring the temperature in the conduit, wherein a sensed temperature exceeding a first threshold value indicates the presence of pulp in the conduit, which triggers the lowering of the pump speed of the vacuum pump.
  • Another advantageous embodiment of the method involves a step of closing a valve in the conduit if the sensed temperature exceeds a second threshold value or if the sensed temperature stays above the first threshold value for a predetermined period of time.
  • Fig. 1 is a schematic illustration of an embodiment of the arrangement in accordance with the invention.
  • Fig. 1 schematically shows an embodiment of a pump arrangement 1 in accordance with the invention.
  • the arrangement comprises a housing 2 in which a pulp pump 4 for pumping pulp is arranged.
  • the pulp pump 4 has an inlet 10 into which pulp is fed, and an outlet 1 1 from which pulp is fed under pressure.
  • the pulp pump 4 is driven by a motor 12 via a shaft 3.
  • the housing 2 is defined as the housing of the whole pulp pump 4, including a pump housing 2 a in which the pulp is affected by the pump action of the pump wheel (not shown), and a shaft housing 2b covering the part of the shaft 3 adjacent the pump housing 2a.
  • the overall housing may consist of several interconnected housings, but in this application the term housing 2 is meant to include all these different housings, e.g. the pump housing 2a and the shaft housing 2b, even though the housing 2 may consist of separate but interconnected parts.
  • a vacuum pump 5 for degassing the pulp inside the housing 2 is connected to the housing 2 via a gas outlet 7 of the housing 2 and a conduit 6.
  • a problem that may occur in connection to the use of such vacuum pumps is that pulp may follow the gas into the conduit 6 and impede the evacuation of gas. Therefore the gas outlet 7 has to be located at a location of the housing 2 where pulp will normally not enter.
  • the pump is a centrifugal pump that presses the pulp in the radial direction by centrifugal forces towards the circumferential walls of the pump housing 2 a and out through the outlet 1 1.
  • the gas outlet 7 should be located in an axial extension of the housing 2 (not its radial extension). Therefore, the gas outlet 7 may be located at the inlet 10 or, as is conventional, in the shaft housing 2b which covers the connection of the shaft 3 to the pump housing 2a. Of course this implies that there is a connection for the gas to pass from the pump housing 2a to the shaft housing 2b. Gas may then be sucked by the vacuum pump 5 from inside the pump housing 2a, via the shaft housing 2b and into the gas outlet 7.
  • One way of solving the problem of pulp in the conduit 6 would be to arrange a spring loaded valve in order to let in air into the conduit when the pressure in the conduit reaches below a certain value.
  • Such a control system would however only allow for two control levels, one in which the valve is closed and a second in which the valve is open. Further, it would not be power efficient, as the vacuum pump 5 would be fully active regardless of the needed suction effect.
  • control unit 13 and an interconnected sensor 8.
  • the connection is in the figure indicated by a dotted line.
  • the sensor 8 is arranged in connection to the gas outlet 7, preferably inside the conduit 6, for detecting the presence of pulp in the conduit 6.
  • control unit 13 is arranged to lower the pump speed of the vacuum pump 5 if pulp is detected in the conduit 6.
  • the connection between the control unit and the vacuum pump 5 is in the figure indicated by a dotted line. In this manner, the suction force of the vacuum pump 5 may be lowered by simply reducing the effect by which the vacuum pump 5 is working. Hence, electrical energy may be saved with respect to conventional solutions.
  • control unit 13 may be set to keep down the pump speed of the vacuum pump 5 for a certain period of time, such as e.g. approximately 5, 10, 15 or 20 seconds, in order to allow sufficiently time for the pulp that has entered the conduit to slip down by gravity and out of the conduit.
  • the sensor 8 for detecting pulp in the conduit is a temperature sensor, e.g. a thermometer, for sensing the temperature in the conduit 6.
  • the temperature of the pulp suspension is between 45 and 95°C and most often between 70 and 95°C.
  • the temperature of the gas inside the housing 2 is more or less the same as that of the pulp.
  • the conduit 6 is cooled by the surrounding air such that the temperature of the gas inside the conduit 6 is lower than the temperature of the pulp in the housing 2.
  • the temperature of the gas decreases continuously in the conduit 6 from the gas outlet 7 of the housing 2 to the vacuum pump 5. If pulp enters the conduit 6 the temperature in the conduit will rise, which will be detected by the temperature sensor.
  • the temperature sensor In order to detect the presence of pulp in the conduit in reliable way the temperature sensor should be placed relatively close to the gas outlet 7, i.e. 2-20 cm from the gas outlet 7 and preferably 5- 10 cm from the gas outlet 7. If the detector is placed too close to the outlet 7 it may be influenced by normal deviations in the pulp flow and if it is placed too far from the outlet it may detect the presence of pulp at a too late stage. However, the most advantageous location of the sensor 8 is dependent of the width of the conduit 6 and other site specific parameters. Therefore the most
  • advantageous location of the temperature sensor is site specific and may therefore advantageously be determined by the skilled person by means of empirical tests.
  • the temperature increase may typically be set to 5 to 30°C.
  • the threshold value may also be set to correspond to a specific temperature that is e.g. 5 to 30°C higher than the normal operation temperature in the conduit.
  • the sensor is either set to send an indication to the the control unit 13 whenever a certain increase of temperature in the conduit 6 has been detected, or whenever the sensed temperature in the conduit 6 has reached above a certain predetermined temperature.
  • the threshold value is either a specific temperature, or a specific temperature raise with respect to the normal operation temperature.
  • the threshold value should not be set to small, or to close to the normal operation temperature, as it then may be influenced by normal deviations in the pulp flow, but on the other hand it should not be set too high as it may then risk to detect the presence of pulp in the conduit at a too late stage.
  • control unit 13 may be set to respond to a sudden increase of temperature instead of an increase of a certain magnitude.
  • the possibility of controlling the vacuum pump 5 may be achieved in a great number of ways that has not been possible until now.
  • the sensor 8 may instead be an optical sensor or any other kind of suitable sensor.
  • control unit 13 is connected to a frequency converter, which is adapted to control the pump speed of the vacuum pump 5.
  • a control valve 9 may be arranged in the conduit for closing the passage of the same.
  • the control valve 9 may e.g. be closed at a start up procedure of the pulp pump, in order to avoid that pulp enters the conduit 6 due to excessive pressure inside the pulp housing 2.
  • the control valve 9 may however also be controlled by the control unit 13, e.g. the control valve 9 may be automatically closed in the event of detection of the presence of pulp in the conduit 6 over a certain period of time, i.e. when the lowering of the pump speed of the vacuum pump 5 is not enough to obtain the desired effect of returning the pulp from the conduit 6 into the housing 2.
  • control valve 9 may be arranged in the conduit 6 for closing its passage in the event of detection of a raise of temperature above a predetermined second threshold value, which is higher than the first threshold value. This would have generally the same effect as closing the valve after a certain period of time of high temperature, i.e. to obtain the desired effect of safely returning the pulp from the conduit 6 into the housing 2.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Paper (AREA)
  • Degasification And Air Bubble Elimination (AREA)

Abstract

Method and arrangement (1) for pumping pulp, which arrangement comprises a housing (2) in which a pulp pump (4) for pumping pulp is arranged, wherein a vacuum pump (5) for degassing the pulp inside the housing (2) is connected via a conduit (6)to a gas outlet (7) of the housing (2).A control unit (13)is arranged to control the pump speed of the vacuum pump(5)and in that the control unit (13)is connected to a sensor (8) that is arranged in connection to the gas outlet (7) for detecting the presence of pulp in the conduit (7),wherein the control unit (13)is arranged to lower the pump speed of the vacuum pump(5)if pulp is detected in the conduit(6).

Description

ARRANGEMENT FOR DEGASSING CONTROL
TECHNICAL FIELD
The invention relates to an arrangement in a pulp pumping process, and in particular the invention relates to an arrangement for degassing control in a pulp pumping process where pulp is pumped and simultaneously degassed.
BACKGROUND
In pulp pumping arrangements, gas (e.g. air) accompanying the pulp causes problems. Typically, the gas tends to cumulate to bubbles that are
accumulated upstream of the pump. Therefore, a vacuum pump is often connected via a conduit to the pulp pumping area, in order to create a sub pressure to evacuate the unwanted gas.
A problem with such arrangements is that pulp may follow the gas into the vacuum pump conduit and cause problems. Firstly, the pulp may completely or at least heavily impede the evacuation of gas such that the gas bubbles still may be accumulated in the pulp that is being pumped. Further, the pulp may get sucked into the vacuum pump and thereby compromise its function. In WO 02 / 075047 this problem is solved by arranging a means for supplying flushing water into the conduit, such that unwanted pulp is flushed away from the conduit. However, this solution is not fully satisfactory as it results in an unwanted dilution of the pulp, or, if the flow of water is too small, an unsatisfactory removal of pulp from the conduit. Hence, a compromise arises where the operator has to choose between an unwanted dilution, and an unsatisfactory removal of pulp from the conduit.
WO 03/014572 discloses a centrifugal pump for pumping a pulp suspension in which the amount of liquid added to the pulp may be reduced in that liquid is only added to the system upstream of the vacuum pump, whereas in conventional arrangements liquid has also been added downstream of the vacuum pump in order to guarantee its well function.
Both of these arrangements do however imply a dilution of the pulp, and further, they allow very small possibilities to control the evacuation of gas from the pulp pumping chamber. SUMMARY
An object of the invention is to provide an improved arrangement and method for pumping pulp, which eliminate or reduce the problems of the prior art cited above, and which allows better control of the evacuation of gas from the pulp pumping chamber.
According to a first aspect the invention relates to an arrangement for pumping pulp, which arrangement comprises a housing in which a pulp pump for pumping pulp is arranged, wherein a vacuum pump for degassing the pulp inside the housing is connected via a conduit to a gas outlet in the housing. A control unit is arranged to control the pump speed of the vacuum pump and the control unit is connected to a sensor that is arranged in the conduit for detecting the presence of pulp in the conduit, wherein the control unit is arranged to lower the pump speed of the vacuum pump if pulp is detected in the conduit.
According to a second aspect the invention relates to a method of pumping pulp by means of a pulp pump located inside a housing, which method comprises: degassing the pulp that is being pumped inside the housing by means of a vacuum pump, which is connected via a conduit to said housing. The method further comprises: sensing if pulp is present in the conduit, indicating to a control unit if pulp is present in the conduit, and controlling the vacuum pump in response to the indication received by the control unit.
With the invention according to the first and second aspect the problems of the prior art are eliminated or at least reduced, and further, a better control of the evacuation of gas from the pulp pumping chamber may be achieved.
In an advantageous embodiment of the method according to the invention the control unit is arranged to lower the pump speed, i.e. the rotation speed of the vacuum pump if pulp is detected in the conduit.
In another advantageous embodiment the sensing of pulp comprises the step of measuring the temperature in the conduit, wherein a sensed temperature exceeding a first threshold value indicates the presence of pulp in the conduit, which triggers the lowering of the pump speed of the vacuum pump.
Another advantageous embodiment of the method involves a step of closing a valve in the conduit if the sensed temperature exceeds a second threshold value or if the sensed temperature stays above the first threshold value for a predetermined period of time.
Further embodiments of the invention are presented in the detailed
description and the dependent claims. The invention, and further objects and advantages of it, is best understood from the following detailed description with reference to the appended drawing, wherein:
Fig. 1 is a schematic illustration of an embodiment of the arrangement in accordance with the invention.
DETAILED DESCRIPTION
Fig. 1 schematically shows an embodiment of a pump arrangement 1 in accordance with the invention. The arrangement comprises a housing 2 in which a pulp pump 4 for pumping pulp is arranged. The pulp pump 4 has an inlet 10 into which pulp is fed, and an outlet 1 1 from which pulp is fed under pressure. The pulp pump 4 is driven by a motor 12 via a shaft 3.
In this application the housing 2 is defined as the housing of the whole pulp pump 4, including a pump housing 2 a in which the pulp is affected by the pump action of the pump wheel (not shown), and a shaft housing 2b covering the part of the shaft 3 adjacent the pump housing 2a.
Conventionally, the overall housing may consist of several interconnected housings, but in this application the term housing 2 is meant to include all these different housings, e.g. the pump housing 2a and the shaft housing 2b, even though the housing 2 may consist of separate but interconnected parts.
As described above, problems may arise due to gas, e.g. air, surrounding the pulp getting mixed into the pulp. Therefore, a vacuum pump 5 for degassing the pulp inside the housing 2 is connected to the housing 2 via a gas outlet 7 of the housing 2 and a conduit 6. A problem that may occur in connection to the use of such vacuum pumps is that pulp may follow the gas into the conduit 6 and impede the evacuation of gas. Therefore the gas outlet 7 has to be located at a location of the housing 2 where pulp will normally not enter. In the shown embodiment the pump is a centrifugal pump that presses the pulp in the radial direction by centrifugal forces towards the circumferential walls of the pump housing 2 a and out through the outlet 1 1. Hence, in order to minimize the pulp in the conduit 6, the gas outlet 7 should be located in an axial extension of the housing 2 (not its radial extension). Therefore, the gas outlet 7 may be located at the inlet 10 or, as is conventional, in the shaft housing 2b which covers the connection of the shaft 3 to the pump housing 2a. Of course this implies that there is a connection for the gas to pass from the pump housing 2a to the shaft housing 2b. Gas may then be sucked by the vacuum pump 5 from inside the pump housing 2a, via the shaft housing 2b and into the gas outlet 7.
However, if an efficient degassing is to be achieved, it is not possible to totally prevent pulp from following the sucked out gas, no matter where the gas outlet 7 is located. Hence, there will always be a risk that pulp enters the conduit 6.
One way of solving the problem of pulp in the conduit 6 would be to arrange a spring loaded valve in order to let in air into the conduit when the pressure in the conduit reaches below a certain value. Such a control system would however only allow for two control levels, one in which the valve is closed and a second in which the valve is open. Further, it would not be power efficient, as the vacuum pump 5 would be fully active regardless of the needed suction effect.
In the arrangement according to the invention this is instead solved by means of a control unit 13 and an interconnected sensor 8. The connection is in the figure indicated by a dotted line. The sensor 8 is arranged in connection to the gas outlet 7, preferably inside the conduit 6, for detecting the presence of pulp in the conduit 6. Further, the control unit 13 is arranged to lower the pump speed of the vacuum pump 5 if pulp is detected in the conduit 6. The connection between the control unit and the vacuum pump 5 is in the figure indicated by a dotted line. In this manner, the suction force of the vacuum pump 5 may be lowered by simply reducing the effect by which the vacuum pump 5 is working. Hence, electrical energy may be saved with respect to conventional solutions. Also, the control unit 13 may be set to keep down the pump speed of the vacuum pump 5 for a certain period of time, such as e.g. approximately 5, 10, 15 or 20 seconds, in order to allow sufficiently time for the pulp that has entered the conduit to slip down by gravity and out of the conduit.
A further problem is how to detect that pulp enters the conduit 6. In a specific advantageous embodiment of the invention the sensor 8 for detecting pulp in the conduit is a temperature sensor, e.g. a thermometer, for sensing the temperature in the conduit 6. Normally, the temperature of the pulp suspension is between 45 and 95°C and most often between 70 and 95°C. The temperature of the gas inside the housing 2 is more or less the same as that of the pulp. However, the conduit 6 is cooled by the surrounding air such that the temperature of the gas inside the conduit 6 is lower than the temperature of the pulp in the housing 2. The temperature of the gas decreases continuously in the conduit 6 from the gas outlet 7 of the housing 2 to the vacuum pump 5. If pulp enters the conduit 6 the temperature in the conduit will rise, which will be detected by the temperature sensor. In order to detect the presence of pulp in the conduit in reliable way the temperature sensor should be placed relatively close to the gas outlet 7, i.e. 2-20 cm from the gas outlet 7 and preferably 5- 10 cm from the gas outlet 7. If the detector is placed too close to the outlet 7 it may be influenced by normal deviations in the pulp flow and if it is placed too far from the outlet it may detect the presence of pulp at a too late stage. However, the most advantageous location of the sensor 8 is dependent of the width of the conduit 6 and other site specific parameters. Therefore the most
advantageous location of the temperature sensor is site specific and may therefore advantageously be determined by the skilled person by means of empirical tests.
When a raise of temperature above a predetermined threshold value is detected by the sensor 8 in the conduit 6, this indicates the presence of pulp in the conduit 6, which in turn triggers the control unit 13 to lower the pump speed of the vacuum pump 5. The threshold value for this
temperature increase may typically be set to 5 to 30°C. Also, since the temperature of the pulp often remains the same, the threshold value may also be set to correspond to a specific temperature that is e.g. 5 to 30°C higher than the normal operation temperature in the conduit. Hence, the sensor is either set to send an indication to the the control unit 13 whenever a certain increase of temperature in the conduit 6 has been detected, or whenever the sensed temperature in the conduit 6 has reached above a certain predetermined temperature. In other words, the threshold value is either a specific temperature, or a specific temperature raise with respect to the normal operation temperature.
In correspondence to the distance of the sensor from the outlet, the threshold value should not be set to small, or to close to the normal operation temperature, as it then may be influenced by normal deviations in the pulp flow, but on the other hand it should not be set too high as it may then risk to detect the presence of pulp in the conduit at a too late stage.
Also, the control unit 13 may be set to respond to a sudden increase of temperature instead of an increase of a certain magnitude. In fact, due to combined effect of the control unit 13 and the sensor, the possibility of controlling the vacuum pump 5 may be achieved in a great number of ways that has not been possible until now.
As an alternative to a temperature sensor the sensor 8 may instead be an optical sensor or any other kind of suitable sensor.
In an advantageous embodiment of the invention, the control unit 13 is connected to a frequency converter, which is adapted to control the pump speed of the vacuum pump 5. An advantage of using a frequency converter in this manner is that it allows continuous and stepless control of the vacuum pump in a most energy efficient way, since no energy is wasted.
As a complement to the vacuum pump, a control valve 9 may be arranged in the conduit for closing the passage of the same. The control valve 9 may e.g. be closed at a start up procedure of the pulp pump, in order to avoid that pulp enters the conduit 6 due to excessive pressure inside the pulp housing 2. In an advantageous embodiment of the invention, the control valve 9 may however also be controlled by the control unit 13, e.g. the control valve 9 may be automatically closed in the event of detection of the presence of pulp in the conduit 6 over a certain period of time, i.e. when the lowering of the pump speed of the vacuum pump 5 is not enough to obtain the desired effect of returning the pulp from the conduit 6 into the housing 2. As an
alternative, the control valve 9 may be arranged in the conduit 6 for closing its passage in the event of detection of a raise of temperature above a predetermined second threshold value, which is higher than the first threshold value. This would have generally the same effect as closing the valve after a certain period of time of high temperature, i.e. to obtain the desired effect of safely returning the pulp from the conduit 6 into the housing 2.
Above, a specific embodiment of the invention has been described, in order to explain the invention. However, the invention is not limited to this
embodiment. Instead it the scope of the invention is defined by the appended claims.

Claims

1. An arrangement (1) for pumping pulp, which arrangement comprises a housing (2) in which a pulp pump (4) for pumping pulp is arranged, wherein a vacuum pump (5) for degassing the pulp inside the housing (2) is
connected via a conduit (6) to a gas outlet (7) of the housing (2),
characterised in that a control unit (13) is arranged to control the pump speed of the vacuum pump (5) and in that the control unit (13) is connected to a sensor (8) that is arranged in connection to the gas outlet (7) for detecting the presence of pulp in the conduit (6), wherein the control unit (13) is arranged to lower the pump speed of the vacuum pump (5) if pulp is detected in the conduit (6).
2. The arrangement (1) according to claim 1 , wherein the sensor (8) is a temperature sensor for sensing the temperature in the conduit (6) and wherein a detected raise of temperature exceeding a predetermined threshold value indicates the presence of pulp in the conduit (6) that triggers the control unit (13) to lower the pump speed of the vacuum pump (5).
3. The arrangement according to claim 2, wherein a control valve (9) is arranged in the conduit for closing the same in the event of detection of a raise of temperature above a predetermined second threshold value, which is higher than the first threshold value.
4. The arrangement (1) according to any of the preceding claims, wherein the control unit (13) is connected to a frequency converter adapted to control the pump speed of the vacuum pump (5).
5. The arrangement (1) according to any of the preceding claims, wherein a control valve (9) is arranged in the conduit for closing the same in the event of detection of the presence of pulp in the conduit (6) over a certain period of time.
6. A method of pumping pulp by means of pulp pump (4) located inside a housing (2), which method comprises:
- degassing the pulp that is being pumped inside the housing (2) by means of a vacuum pump (5), which is connected via a conduit (6) to said housing (2), characterised in that the method further comprises:
sensing if pulp is present in the conduit (6),
indicating to a control unit (13) if pulp is present in the conduit (6), - controlling the vacuum pump (5) in response to the indication received by the control unit (13).
7. The method according to claim 6, wherein the control unit ( 13) is arranged to lower the pump speed of the vacuum pump (5) if pulp is detected in the conduit (6).
8. The method according to claim 7, wherein the sensing of pulp comprises the step of measuring the temperature in the conduit, and wherein a sensed temperature raise that exceeds a first threshold value indicates the presence of pulp in the conduit (6), which triggers the lowering of the pump speed of the vacuum pump (5).
9. The method according to claim 8, further comprising a step of closing a valve in the conduit if the sensed temperature exceeds a second threshold value or if the sensed temperature stays above the first threshold value for a predetermined period of time.
EP11780884A 2010-05-10 2011-04-29 Arrangement for degassing control Withdrawn EP2569482A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE1050462A SE535003C2 (en) 2010-05-10 2010-05-10 Device for degassing control
PCT/SE2011/050538 WO2011142711A1 (en) 2010-05-10 2011-04-29 Arrangement for degassing control

Publications (1)

Publication Number Publication Date
EP2569482A1 true EP2569482A1 (en) 2013-03-20

Family

ID=44914583

Family Applications (1)

Application Number Title Priority Date Filing Date
EP11780884A Withdrawn EP2569482A1 (en) 2010-05-10 2011-04-29 Arrangement for degassing control

Country Status (5)

Country Link
EP (1) EP2569482A1 (en)
CN (1) CN102869833B (en)
BR (1) BR112012028840A2 (en)
SE (1) SE535003C2 (en)
WO (1) WO2011142711A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI20245126A1 (en) 2024-02-08 2025-08-09 Andritz Oy METHOD AND APPARATUS FOR REMOVING GAS FROM A GAS-CONTAINING FIBRE SUSPENSION USING A CENTRIFUGAL PUMP

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4435193A (en) * 1980-04-07 1984-03-06 Kamyr Ab Controlling operation of a centrifugal pump
FI110708B (en) * 1990-08-14 2003-03-14 Sulzer Pumpen Ag Arrangement and method for treating a gas and / or air-containing liquid and / or pulp suspension with a centrifugal pump and use of a centrifugal pump
FI87247C (en) * 1990-08-14 1992-12-10 Ahlstroem Oy Feeding arrangement and method of a paper machine for processing a fiber pulp stream
FI94440C (en) * 1990-08-14 1995-09-11 Ahlstroem Oy Process and plant for treating air and / or gas-containing liquid or fiber suspension and use of a gas separating pulp pump
NZ308546A (en) * 1995-06-05 1999-07-29 Ahlstroem Oy Method of controlling the function of a centrifugal pump and vacuum pump combination, and a gas-separating centrifugal pump
DE19781894T1 (en) * 1996-07-26 1999-09-02 Yokota Mfg Self-priming centrifugal pump
SE518694C2 (en) * 2001-03-21 2002-11-05 Metso Paper Inc The pumping device
FI20031045A0 (en) * 2003-07-09 2003-07-09 Sulzer Pumpen Ag Process and apparatus for treating pulp

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
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CN102869833B (en) 2015-04-22
BR112012028840A2 (en) 2016-07-26
SE535003C2 (en) 2012-03-13
WO2011142711A1 (en) 2011-11-17
CN102869833A (en) 2013-01-09
SE1050462A1 (en) 2011-11-11

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