EP3570982A1 - Centrifuge and method for maintaining a process liquid using a centrifuge - Google Patents

Centrifuge and method for maintaining a process liquid using a centrifuge

Info

Publication number
EP3570982A1
EP3570982A1 EP18741522.9A EP18741522A EP3570982A1 EP 3570982 A1 EP3570982 A1 EP 3570982A1 EP 18741522 A EP18741522 A EP 18741522A EP 3570982 A1 EP3570982 A1 EP 3570982A1
Authority
EP
European Patent Office
Prior art keywords
centrifuge
process liquid
cone shaped
container
shaped container
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Withdrawn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
EP18741522.9A
Other languages
German (de)
French (fr)
Other versions
EP3570982A4 (en
Inventor
Thomas TYGESEN SCHMIDT
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.)
Et Teknik AS
Original Assignee
Et Teknik AS
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 Et Teknik AS filed Critical Et Teknik AS
Publication of EP3570982A1 publication Critical patent/EP3570982A1/en
Publication of EP3570982A4 publication Critical patent/EP3570982A4/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B11/00—Feeding, charging, or discharging bowls
    • B04B11/08—Skimmers or scrapers for discharging ; Regulating thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B9/00—Drives specially designed for centrifuges; Arrangement or disposition of transmission gearing; Suspending or balancing rotary bowls
    • B04B9/02—Electric motor drives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B9/00—Drives specially designed for centrifuges; Arrangement or disposition of transmission gearing; Suspending or balancing rotary bowls
    • B04B9/10—Control of the drive; Speed regulating

Definitions

  • the invention relates to maintaining the quality of process liquid by means of centrifugation, where solid dirt particles are separated from liquids by means of centrifugal force.
  • a cone shaped container is put into fast rotation by means of an electric motor. Solid particles in the process liquid with a density that is higher than the density of the process liquid will settle on the inner wall of the cone shaped container.
  • an apparatus for removal of particles from a process liquid comprising an inner centrifuge surface with a rotational axis and a motor which via a shaft is connected to the centrifuge surface, said motor having means for driving the centrifuge with high revolution speed, so that the process liquid can be brought against the inner centrifuge surface, where particles with higher density than the liquid will be able to settle against the inner centrifuge surface.
  • the apparatus comprises a second motor that possesses means for driving the centrifuge with a low revolution speed and a high torque, so that process liquid can escape the centrifuge surface by means of gravity, and where there is also provided a movable scraper which via an actuator is adapted to be moved between a position, in which there is a clearance in relation to the centrifuge surface and a position, in which it is in engagement with the centrifuge surface.
  • the rotation of the centrifuge surface stops, and the second motor is activated so that the centrifuge now rotates with low revolution speed and high torque, while at the same time, the knife or scraper is brought into engagement with the inner surface of the centrifuge. Movement between the scraper and the centrifuge surface will now ensure that the settled particles or the sludge is scraped off of the centrifuge surface and can easily be removed from the centrifuge.
  • the axis of rotation is vertical, and that the centrifuge surface has an upper and a lower rim, said centrifuge surface being open in a downwards direction where also an inlet for process liquid is provided at an upper or lower rim of the centrifuge surface, and where an outlet for process liquid is provided opposite the inlet.
  • the process liquid can be directed to the centrifuge surface via an upper or lower rim thereof, and as a result of the fast rotating centrifuge, the liquid will settle against the inner centrifuge surface during service and can escape the centrifuge at the opposite end in relation to the injection end via suitable holes.
  • This design makes it possible that the centrifuge can be conical, so that it has a larger diameter at one end compared to the other, and henceforth, the centrifuge will be able to contain larger amounts of settled particles. This contributes to reducing the interruptions for scraping off of the solid settled particles.
  • the inlet for process liquid or the injection system comprises a nozzle that is mounted on a movable scraper in such a way that when the scraper is moved to the position where there is a clearance in relation to the centrifuge surface, the nozzle will be positioned for injection of process liquid radially in relation to the centrifuge surface.
  • both the nozzle and the scraper must be active within the centrifuge in such a way that when the scraper is active there is no injection of process liquid, and when the scraper is inactive, typically, service of the centrifuge with high revolutions and injection of process liquid will occur.
  • the nozzle as well as the scraper can for instance be inserted into the centrifuge via the downwards facing opening thereof and be made to swivel, for instance via a shaft, between the two positions: the position in which the nozzle is active, and the position in which the scraper is active.
  • the second motor comprises a linear actuator with a direction of movement that is perpendicular to the rotational axis of the centrifuge surface and a worm drive or gear wheel on the shaft of the centrifuge, said actuator furthermore comprising a pawl that is adapted to engagement with the gear wheel when the actuator is moved in a first direction, and where the pawl is adapted to avoid engagement with the worm drive or gear wheel during movement in a second direction opposite to the first direction.
  • This apparatus gives, with simple means, the opportunity to drive the centrifuge by means of the repeated movements back and forth of the linear actuator with engagement via the pawl for instance at each forward movement. In this way, it is possible for the linear actuator to transfer a large torque to the centrifuge.
  • the invention relates to a method for maintaining process liquids by means of centrifuging, by which heavy particles are separated from liquids by means of centrifugal force in a cone shaped container, having the smallest diameter lowest, and in which settled solid particles are pushed towards the top of the cone shape by means of centrifugal force.
  • the process liquid escapes the centrifuge through holes either in the lower or upper part of the cone shaped container, where the purified liquid can be collected in a separate chamber.
  • the separate chamber is provided as a stationary ring shaped chamber around the centrifuge and collects the process liquid when it escapes the centrifuge. From here it is easy to collect the liquid and possibly direct it back to the process in which it takes part.
  • the process liquid is directed to outlet holes at the upper part of the cone shaped container, and that the process liquid is injected into the container via an injection nozzle at the lower part.
  • the cone shaped container is open downwards so that a nozzle with an inlet belonging thereto can be entered into the centrifuge, and that the unpurified process liquid in this way is directed in a radial direction out towards the centrifuge surface during service of the centrifuge.
  • the outlet holes are provided in the upper end of the cone shaped container, the amount of unpurified process liquid that has settled on top of possible settled particles flow down and out of the centrifuge, when the rotation thereof is stopped, and, consequently, this unpurified liquid will escape in the same direction as the settled sludge, when this is scraped off.
  • Scraper and nozzle are both elements that are not rotated together with the centrifuge and, conveniently, they can be mounted together.
  • Scraping off of solid settled particles from the inner side of the cone shaped container is executed by means of a swivelling knife or scraper that is pushed out towards the inner side of the cone shaped container.
  • this can take place during slow forward movement of the centrifuge, when maintaining the engagement of the scraper with the inner surface of the centrifuge.
  • a worm drive or gear wheel on the input shaft of the container is used for obtaining slow rotation with a large torque, said gear wheel being activated by means of a linear actuator, for instance a pneumatic cylinder, for scraping off of settled particles from the inner side of the cone shaped container during the engagement of the swivelling knife with the inner side of the container.
  • a linear actuator for instance a pneumatic cylinder
  • the linear actuator can be designed to give an arbitrarily high torque during the slow advance of the centrifuge.
  • Fig. 1 shows a sectional view of the invention
  • Fig. 2 shows a sectional view of the cylindrical container during service
  • Fig. 3 shows a sectional view of an apparatus according to the invention
  • Fig. 4 shows a sectional view of a plane perpendicular to the plane shown in Fig. 1 ,
  • Fig. 5 is a 3D view of the knife and the corresponding actuator as well as the injection system and the injection nozzle for process water,
  • Fig. 6 shows a sectional view of a centrifuge according to the invention
  • Fig. 7 shows a further sectional view that is rotated 90 degrees in relation to the sectional view in Fig. 6 of an embodiment according to the invention
  • Fig. 8a, Fig. 8b and Fig. 8c each shows a side view of the invention from three different sides.
  • Fig. 1 and Fig. 2 show how process liquid 5 is pushed outwards in the cone shaped container 3, when it is rotated as a centrifuge via a direct drive to the electric motor 1 , after which the liquid 5 seeps out through a number of holes 7 and into a separate chamber 8, after which the liquid flows back to the process purified from solid dirt particles.
  • the passage of the liquid out through the holes 7 is in this embodiment indicated by means of arrows 14.
  • the novel feature of the invention is that after a period of time the cone shaped container is braked and the rotation stops.
  • the process liquid that might have settled on the inside of the centrifuge flows during the braking down into a vessel 16 under the centrifuge or the cone shaped container 3.
  • the solid settled dirt particles 4 remain on the inner wall of the cone shaped container.
  • the vessel 16 under the cone shaped container 3 can be turned away before a scraper 6 for instance in a way where a knife 6 is moved out into the settled dirt particles 4, after which the vessel 16 is again put under the container 3.
  • the cone shaped container 3 is rotated slowly by means of a worm drive or a gear wheel 2.1 that is mounted on the drive shaft of the container, as it is shown in Fig. 4.
  • the gear wheel 2.1 is driven by means of a translating linear actuator, as for instance a pneumatic cylinder 2.4, which engages with the gear wheel 2.1 at its motion in a first direction towards the position B 2.5, and avoids engagement with the gear wheel when moved in the opposite direction towards position A 2.6.
  • a translating linear actuator as for instance a pneumatic cylinder 2.4
  • a spring loaded pawl 2.2 is located at the outermost end of the actuator in such a way that the pawl 2.2 at the motion in the first direction retracts from the teeth of the gear wheel, but at the motion in the opposite direction catches a tooth on the gear wheel 2.1.
  • the settled dirt particles 4 are
  • a collecting vessel 16 that is also referred to as a sludge container or a trash container.
  • the actuator 2.4 moves back and forth, until the cone shaped container 3 has moved so many times that the settled particles are removed by scraping.
  • This worm or gear drive on the input shaft to the container 3 ensures a slow rotation with a large torque, as the gear wheel is activated to scrape out the settled particles 4 from the inside of the cone shaped container during the engagement of the swivelling knife against the inside of the container.
  • the knife or scraper 6 is mounted on a swivelling system, as for instance shown in Fig. 5, which moves the scraper out of the bottom and is activated by means of a pneumatic cylinder 6.2 outside the centrifuge.
  • a pneumatic cylinder 6.2 outside the centrifuge.
  • the injection point for the injection nozzle for the process liquid can be adjusted by means of a threaded spindle 6.1 . This is a result of the fact that the injection nozzle is mounted unto the back side of the scraper and follows the movement thereof accordingly.
  • a process for maintaining process liquids by means of centrifuging is devised, and in which process the settled particles 4 are separated from liquids by means of centrifugal force in a cone shaped container 3 having the smallest diameter downwards, where settled solid particles are pushed towards the top of the cone shape by means of centrifugal force.
  • the process liquid can escape the centrifuge through holes either in the lower part (as in the embodiment shown in Fig. 3, Fig. 6 or Fig. 7) or in the upper part (as in the embodiment in Fig. 1 ) in the cone shaped container 3, wherefrom the now cleaner liquid can be collected in a separate chamber 8.
  • the holes for the outlet is located in the upper end of the conical container and that the process liquid has an injection nozzle 9 in the lower end, which is also shown in Fig. 1 . If the holes are located in the lower end, as shown in Figs. 3, 6 or 7, relatively unpurified liquid will escape through the holes during braking from high to low rotational speed, which is not desirable. This will not take place if the holes are located in the upper end and even located in an upper end plate of the cylindrical container.
  • Fig. 8a-8c shows the apparatus seen from the outside and an outlet 1 1 for purified process liquid that is collected in the separate chamber 8 is indicated. Unpurified process liquid that for instance escapes the centrifuge in a downwards direction during braking is collected in the cone shaped element and can be directed back to a tank 15 for unpurified process liquid.
  • Fig. 8a-8c shows the apparatus seen from the outside and an outlet 1 1 for purified process liquid that is collected in the separate chamber 8 is indicated.
  • Unpurified process liquid that for instance escapes the centrifuge in a downwards direction during braking is collected in the cone shaped element and can be directed back to a tank 15 for unpurified process liquid.
  • both the container 18 and the sludge container 16 are shown, and a system will be provided to place each of them under the centrifuge according to the current process step, so that the sludge container is moved under the centrifuge when scraping off of settled particles takes place.
  • the nozzle 9 is for instance shown in Fig. 6 and a hose or a duct for addition of process water will be provided, but it is only shown
  • a feed pump 12 and a control valve 10 will be provided, so that the injection of unpurified process liquid can be controlled in an appropriate manner.
  • FIG. 1 an overflow 13 from the sludge container 16 is also indicated so that process liquid that has escaped during scraping off of settled particles can be directed back to a tank 15 for unpurified process liquid.
  • the tank 17 for unpurified process liquid and the outlet 1 1 with purified process liquid from the chamber 8 can also be seen.

Landscapes

  • Centrifugal Separators (AREA)

Abstract

The invention relates to an apparatus for removal of particles (4) from a process liquid (5), said apparatus comprising an inner centrifuge surface (3) with a rotational axis and a motor (1 ) which via a shaft is connected to the centrifuge surface (3), said motor (1 ) having means for driving the centrifuge with high revolution speed, so that the process liquid (5) can be brought against the inner centrifuge surface (3), where particles with higher density than the liquid will be able to settle against the inner centrifuge surface, said apparatus being novel in that it comprises a second motor (2.4) that possesses means for driving the centrifuge with a low revolution speed and a high torque, so that process liquid can escape the centrifuge surface by means of gravity, and where there is also provided a movable scraper (6) which via an actuator (6.2) is adapted to be moved between a position, in which there is a clearance in relation to the centrifuge surface and a position, in which it is in engagement with the centrifuge surface.

Description

CENTRIFUGE AND METHOD FOR MAINTAINING A PROCESS
LIQUID USING A CENTRIFUGE
The invention relates to maintaining the quality of process liquid by means of centrifugation, where solid dirt particles are separated from liquids by means of centrifugal force. A cone shaped container is put into fast rotation by means of an electric motor. Solid particles in the process liquid with a density that is higher than the density of the process liquid will settle on the inner wall of the cone shaped container. It is known in connection with automatically emptying centrifuges to separate according to this principle. In the existing centrifuges, the liquid is directed in from the upper end down through the drive shaft and down into a cylindrical container which is cleaned by scraping by means of several cleaning knives that are also rotating. The rotation is stopped, and a gear system makes the knives rotate. In this way there is a high probability of dirt particles remaining on the knives, and as a result the centrifuge will lose balance as the knives are subsequently brought into rotation with the centrifuge. At the same time, it entails complicated technical solutions to direct the liquid down into the cylinder.
Hence, an apparatus for removal of particles from a process liquid is provided, said apparatus comprising an inner centrifuge surface with a rotational axis and a motor which via a shaft is connected to the centrifuge surface, said motor having means for driving the centrifuge with high revolution speed, so that the process liquid can be brought against the inner centrifuge surface, where particles with higher density than the liquid will be able to settle against the inner centrifuge surface. To overcome the problems with the known apparatuses, the apparatus according to the invention comprises a second motor that possesses means for driving the centrifuge with a low revolution speed and a high torque, so that process liquid can escape the centrifuge surface by means of gravity, and where there is also provided a movable scraper which via an actuator is adapted to be moved between a position, in which there is a clearance in relation to the centrifuge surface and a position, in which it is in engagement with the centrifuge surface.
When a suitable amount of solid heavy particles has settled against the inner surface of the centrifuge surface, the rotation of the centrifuge surface stops, and the second motor is activated so that the centrifuge now rotates with low revolution speed and high torque, while at the same time, the knife or scraper is brought into engagement with the inner surface of the centrifuge. Movement between the scraper and the centrifuge surface will now ensure that the settled particles or the sludge is scraped off of the centrifuge surface and can easily be removed from the centrifuge.
It is preferred that the axis of rotation is vertical, and that the centrifuge surface has an upper and a lower rim, said centrifuge surface being open in a downwards direction where also an inlet for process liquid is provided at an upper or lower rim of the centrifuge surface, and where an outlet for process liquid is provided opposite the inlet. By having a vertical axis of rotation and having the centrifuge surface open in a downwards direction, it is possible that scraped off sludge escapes the centrifuge due to gravity by itself. Conveniently, the process liquid can be directed to the centrifuge surface via an upper or lower rim thereof, and as a result of the fast rotating centrifuge, the liquid will settle against the inner centrifuge surface during service and can escape the centrifuge at the opposite end in relation to the injection end via suitable holes. This design makes it possible that the centrifuge can be conical, so that it has a larger diameter at one end compared to the other, and henceforth, the centrifuge will be able to contain larger amounts of settled particles. This contributes to reducing the interruptions for scraping off of the solid settled particles.
The inlet for process liquid or the injection system comprises a nozzle that is mounted on a movable scraper in such a way that when the scraper is moved to the position where there is a clearance in relation to the centrifuge surface, the nozzle will be positioned for injection of process liquid radially in relation to the centrifuge surface. This design is
appropriate, as both the nozzle and the scraper must be active within the centrifuge in such a way that when the scraper is active there is no injection of process liquid, and when the scraper is inactive, typically, service of the centrifuge with high revolutions and injection of process liquid will occur. The nozzle as well as the scraper can for instance be inserted into the centrifuge via the downwards facing opening thereof and be made to swivel, for instance via a shaft, between the two positions: the position in which the nozzle is active, and the position in which the scraper is active.
The second motor comprises a linear actuator with a direction of movement that is perpendicular to the rotational axis of the centrifuge surface and a worm drive or gear wheel on the shaft of the centrifuge, said actuator furthermore comprising a pawl that is adapted to engagement with the gear wheel when the actuator is moved in a first direction, and where the pawl is adapted to avoid engagement with the worm drive or gear wheel during movement in a second direction opposite to the first direction. This apparatus gives, with simple means, the opportunity to drive the centrifuge by means of the repeated movements back and forth of the linear actuator with engagement via the pawl for instance at each forward movement. In this way, it is possible for the linear actuator to transfer a large torque to the centrifuge.
Furthermore, the invention relates to a method for maintaining process liquids by means of centrifuging, by which heavy particles are separated from liquids by means of centrifugal force in a cone shaped container, having the smallest diameter lowest, and in which settled solid particles are pushed towards the top of the cone shape by means of centrifugal force. By this method, a large amount of solid heavy particles can be made to settle from the liquid, before it is necessary to scrape off the settled particles from the liquid from the inner centrifuge surface. As long as the centrifuge is in service with high revolution speed, the downwards facing opening will, due to its smaller diameter, prevent that settled particles and process liquid escape the inner centrifuge surface.
According to the invention the process liquid escapes the centrifuge through holes either in the lower or upper part of the cone shaped container, where the purified liquid can be collected in a separate chamber. The separate chamber is provided as a stationary ring shaped chamber around the centrifuge and collects the process liquid when it escapes the centrifuge. From here it is easy to collect the liquid and possibly direct it back to the process in which it takes part.
It is appropriate if the process liquid is directed to outlet holes at the upper part of the cone shaped container, and that the process liquid is injected into the container via an injection nozzle at the lower part. It is preferred that the cone shaped container is open downwards so that a nozzle with an inlet belonging thereto can be entered into the centrifuge, and that the unpurified process liquid in this way is directed in a radial direction out towards the centrifuge surface during service of the centrifuge. When the outlet holes are provided in the upper end of the cone shaped container, the amount of unpurified process liquid that has settled on top of possible settled particles flow down and out of the centrifuge, when the rotation thereof is stopped, and, consequently, this unpurified liquid will escape in the same direction as the settled sludge, when this is scraped off.
Injection of the process liquid into the cone shaped container takes place on the back side of a swivelling scraper, where a nozzle injects
contaminated process liquid into the cone shaped container at the inner side thereof. Scraper and nozzle are both elements that are not rotated together with the centrifuge and, conveniently, they can be mounted together.
Scraping off of solid settled particles from the inner side of the cone shaped container is executed by means of a swivelling knife or scraper that is pushed out towards the inner side of the cone shaped container.
Conveniently, this can take place during slow forward movement of the centrifuge, when maintaining the engagement of the scraper with the inner surface of the centrifuge.
Preferably, a worm drive or gear wheel on the input shaft of the container is used for obtaining slow rotation with a large torque, said gear wheel being activated by means of a linear actuator, for instance a pneumatic cylinder, for scraping off of settled particles from the inner side of the cone shaped container during the engagement of the swivelling knife with the inner side of the container. With this system, the linear actuator can be designed to give an arbitrarily high torque during the slow advance of the centrifuge. In the following, the invention will be described by means of an
embodiment, referring to the drawings in which:
Fig. 1 shows a sectional view of the invention, Fig. 2 shows a sectional view of the cylindrical container during service,
Fig. 3 shows a sectional view of an apparatus according to the invention,
Fig. 4 shows a sectional view of a plane perpendicular to the plane shown in Fig. 1 ,
Fig. 5 is a 3D view of the knife and the corresponding actuator as well as the injection system and the injection nozzle for process water,
Fig. 6 shows a sectional view of a centrifuge according to the invention,
Fig. 7 shows a further sectional view that is rotated 90 degrees in relation to the sectional view in Fig. 6 of an embodiment according to the invention,
Fig. 8a, Fig. 8b and Fig. 8c each shows a side view of the invention from three different sides.
Fig. 1 and Fig. 2 show how process liquid 5 is pushed outwards in the cone shaped container 3, when it is rotated as a centrifuge via a direct drive to the electric motor 1 , after which the liquid 5 seeps out through a number of holes 7 and into a separate chamber 8, after which the liquid flows back to the process purified from solid dirt particles. The passage of the liquid out through the holes 7 is in this embodiment indicated by means of arrows 14.
The novel feature of the invention is that after a period of time the cone shaped container is braked and the rotation stops. The process liquid that might have settled on the inside of the centrifuge flows during the braking down into a vessel 16 under the centrifuge or the cone shaped container 3. The solid settled dirt particles 4 remain on the inner wall of the cone shaped container.
It is possible that the vessel 16 under the cone shaped container 3 can be turned away before a scraper 6 for instance in a way where a knife 6 is moved out into the settled dirt particles 4, after which the vessel 16 is again put under the container 3.
Subsequently, the cone shaped container 3 is rotated slowly by means of a worm drive or a gear wheel 2.1 that is mounted on the drive shaft of the container, as it is shown in Fig. 4. The gear wheel 2.1 is driven by means of a translating linear actuator, as for instance a pneumatic cylinder 2.4, which engages with the gear wheel 2.1 at its motion in a first direction towards the position B 2.5, and avoids engagement with the gear wheel when moved in the opposite direction towards position A 2.6. In this way, the gear wheel 2.1 is moved one step or one tooth forward and the dome shaped container 3 is rotated accordingly.
As also shown in Fig. 4, a spring loaded pawl 2.2 is located at the outermost end of the actuator in such a way that the pawl 2.2 at the motion in the first direction retracts from the teeth of the gear wheel, but at the motion in the opposite direction catches a tooth on the gear wheel 2.1. At the simultaneous engagement of the knife 6 (shown in Fig. 3) with the inner side of the cone shaped container, the settled dirt particles 4 are
disconnected from the surface, so that they can fall out of the container 3 and down into a collecting vessel 16 that is also referred to as a sludge container or a trash container.
The actuator 2.4 moves back and forth, until the cone shaped container 3 has moved so many times that the settled particles are removed by scraping.
When the pneumatic cylinder 2.4 is in neutral position A 2.6, the stop 2.3 keeps the pawl 2.2 out of the worm drive or the gear wheel 2.1 , an in this way it is possible for the electric motor 1 to make the cone shaped container 3 rotate again.
This worm or gear drive on the input shaft to the container 3 ensures a slow rotation with a large torque, as the gear wheel is activated to scrape out the settled particles 4 from the inside of the cone shaped container during the engagement of the swivelling knife against the inside of the container.
According to the invention the knife or scraper 6 is mounted on a swivelling system, as for instance shown in Fig. 5, which moves the scraper out of the bottom and is activated by means of a pneumatic cylinder 6.2 outside the centrifuge. When the pneumatic cylinder is moved in one direction, the inside of the cone shaped container 3 can be cleaned by scraping, as the knife inside the centrifuge in this way is brought into engagement with the inner surface of the centrifuge.
If the pneumatic cylinder 6.2 is moved in the opposite direction, the injection point for the injection nozzle for the process liquid can be adjusted by means of a threaded spindle 6.1 . This is a result of the fact that the injection nozzle is mounted unto the back side of the scraper and follows the movement thereof accordingly.
Hence, a process for maintaining process liquids by means of centrifuging is devised, and in which process the settled particles 4 are separated from liquids by means of centrifugal force in a cone shaped container 3 having the smallest diameter downwards, where settled solid particles are pushed towards the top of the cone shape by means of centrifugal force.
The process liquid can escape the centrifuge through holes either in the lower part (as in the embodiment shown in Fig. 3, Fig. 6 or Fig. 7) or in the upper part (as in the embodiment in Fig. 1 ) in the cone shaped container 3, wherefrom the now cleaner liquid can be collected in a separate chamber 8. It is preferred, as shown in Fig. 1 , that the holes for the outlet is located in the upper end of the conical container and that the process liquid has an injection nozzle 9 in the lower end, which is also shown in Fig. 1 . If the holes are located in the lower end, as shown in Figs. 3, 6 or 7, relatively unpurified liquid will escape through the holes during braking from high to low rotational speed, which is not desirable. This will not take place if the holes are located in the upper end and even located in an upper end plate of the cylindrical container.
Conveniently, injection of the process liquid into the cone shaped container 3 can take place on the back side of the swivelling knife 6, where a nozzle sprays contaminated process liquid into the top and/or the bottom of the cone shaped container at the inner side thereof. Fig. 8a-8c shows the apparatus seen from the outside and an outlet 1 1 for purified process liquid that is collected in the separate chamber 8 is indicated. Unpurified process liquid that for instance escapes the centrifuge in a downwards direction during braking is collected in the cone shaped element and can be directed back to a tank 15 for unpurified process liquid. In Fig. 3 both the container 18 and the sludge container 16 are shown, and a system will be provided to place each of them under the centrifuge according to the current process step, so that the sludge container is moved under the centrifuge when scraping off of settled particles takes place.
The nozzle 9 is for instance shown in Fig. 6 and a hose or a duct for addition of process water will be provided, but it is only shown
schematically in Fig. 1 . In this connection a feed pump 12 and a control valve 10 will be provided, so that the injection of unpurified process liquid can be controlled in an appropriate manner.
In Fig. 1 an overflow 13 from the sludge container 16 is also indicated so that process liquid that has escaped during scraping off of settled particles can be directed back to a tank 15 for unpurified process liquid. In Fig. 1 , the tank 17 for unpurified process liquid and the outlet 1 1 with purified process liquid from the chamber 8 can also be seen. Reference numerals:
1 . Electric motor for rotation during separation
2. Worm drive for slow rotation during emptying
2.1 Worm gear or gear wheel
2.2 Pawl for engagement with worm gear
2.3 Stop that lifts the pawl 2.2 free from the worm gear during rotation for separation
2.4 Pneumatic cylinder for movement between position A 2.6 and position B 2.5
2.5 Position A
2.6 Position B
3. Cone shaped container
4. Settled solid particles (black)
5. Process liquid (blue)
6. Knife for scraping off of solid particles
6.1 Adjustment of the injection system and the position of the injection nozzle or threaded spindle
6.2 Pneumatic cylinder for movement of knife
7. Holes for outlet in the cone shaped container
8. Separate chamber
9. Injection nozzle for process liquid or process water
10. Flow regulation of injected volume
1 1 . Outlet for purified process liquid
12. Feed pump for injection system and injection nozzle
13. Overflow from sludge container
14. Arrows
15. Tank with unpurified process liquid
16. Sludge container or dirt container
17. Tank with purified process liquid
18. Metal bowl for collection of process liquid

Claims

C L A I M S
Apparatus for removal of particles (4) from a process liquid (5), said apparatus comprising an inner centrifuge surface (3) with a rotational axis and a motor (1 ) which via a shaft is connected to the centrifuge surface (3), said motor (1 ) having means for driving the centrifuge with high revolution speed, so that the process liquid (5) can be brought against the inner centrifuge surface
(3), where particles with higher density than the liquid will be able to settle against the inner centrifuge surface, characterized in that the apparatus comprises a second motor (2.4) that possesses means for driving the centrifuge with a low revolution speed and a high torque, so that process liquid can escape the centrifuge surface by means of gravity, and where there is also provided a movable scraper (6) which via an actuator (6.2) is adapted to be moved between a position, in which there is a clearance in relation to the centrifuge surface and a position, in which it is in engagement with the centrifuge surface.
Apparatus according to claim 1 , characterized in that the axis of rotation is vertical, and that the centrifuge surface has an upper and a lower rim, said centrifuge surface being open in a downward direction where also an inlet for process liquid is provided at an upper or lower rim of the centrifuge surface, and where an outlet for process liquid is provided opposite the inlet.
Apparatus according to claim 2, characterized in that the inlet for process liquid comprises a nozzle (9), said nozzle (9) being mounted to the movable scraper (6), so that when the scraper (6) is moved to the position in which it has a clearance in relation to the centrifuge surface, the nozzle (9) will be positioned to injection of process liquid radially in relation the centrifuge surface.
Apparatus according to claim 2, characterized in that the second motor comprises a linear actuator (2.4) with a direction of
movement that is perpendicular to the rotational axis of the centrifuge surface, and a worm drive or gear wheel (2.1 ) on the shaft of the centrifuge, said actuator (2.4) furthermore comprising a pawl (2.2) that is adapted to engagement with the gear wheel (2.1 ) when the actuator (2.
4) is moved in a first direction (2.5), and where the pawl (2.2) is adapted to avoid engagement with the worm drive or gear wheel (2.1 ) during movement in a second direction (2.6) opposite to the first direction.
5. Method for maintaining process liquids by means of centrifuging, by which heavy particles (4) are separated from liquids by means of centrifugal force in a cone shaped centrifuge and container (3) having the smallest diameter lowest, and in which settled solid particles are pushed towards the top of the cone shape by means of centrifugal force.
6. Method according to claim 5, characterized in that the process liquid escapes the centrifuge through holes (7) either in the lower or upper part of the cone shaped container (3), where the purified liquid can be collected in a separate chamber (8).
7. Method according to claim 6, characterized in that the process liquid is directed to outlet holes at the upper part of the cone shaped container, and that the process liquid is injected into the container via an injection nozzle (9) at the lower part.
8. Method according to claim 7, characterized in that injection of the process liquid into the cone shaped container (3) takes place on the back side of a swivelling scraper (6), where a nozzle
(9) injects contaminated process liquid into the cone shaped container at the inner side thereof.
Method according to claim 8, characterized in that scraping off of solid settled particles (4) from the inner side of the cone shaped container is executed by means of a swivelling knife or scraper (6) that is pushed out towards the inner side of the cone shaped container (3).
10. Method according to claim 9, characterized in that a worm drive or gear wheel (2.1 ) on the input shaft of the container (3) is used for obtaining slow rotation with a large torque, said gear wheel (2.1 ) being activated by means of a linear actuator, for instance a pneumatic cylinder (2.4), for scraping off of settled particles (4) from the inner side of the cone shaped container during the engagement of the swivelling knife (6) with the inner side of the container.
EP18741522.9A 2017-01-17 2018-01-15 Centrifuge and method for maintaining a process liquid using a centrifuge Withdrawn EP3570982A4 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DKBA201700006U DK201700006U3 (en) 2017-01-17 2017-01-17 Installations for removal of particles from process fluid
PCT/DK2018/050006 WO2018133908A1 (en) 2017-01-17 2018-01-15 Centrifuge and method for maintaining a process liquid using a centrifuge

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EP3570982A1 true EP3570982A1 (en) 2019-11-27
EP3570982A4 EP3570982A4 (en) 2020-10-14

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WO (1) WO2018133908A1 (en)

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FR1394980A (en) * 1964-02-27 1965-04-09 Fives Lille Cail Discharge device for discontinuous centrifugal wringer
GB2137537B (en) * 1983-02-05 1985-12-18 Hoccom Developments Limited Centrifuge
US5250180A (en) * 1992-11-10 1993-10-05 Fwu Kuang Enterprises Co., Ltd. Oil recovering apparatus from used lubricant
CA2228340A1 (en) * 1998-01-30 1999-07-30 Jean-Pierre Racine Solid-liquid separator and filter
US6425849B1 (en) * 2001-03-27 2002-07-30 Ronald D. Benson Solid bowl centrifuge with liquid release during rotation
JP3732466B2 (en) * 2002-07-12 2006-01-05 ジー・フォース・ジャパン株式会社 Centrifuge
JP2004113868A (en) * 2002-09-24 2004-04-15 Niigata Power Systems Co Ltd Cylindrical centrifuge
JP4147206B2 (en) * 2004-06-14 2008-09-10 株式会社マルエス機工 Centrifuge
DE102011010621A1 (en) * 2011-02-08 2012-08-09 T & A Trenntechnik & Anlagenbau Gmbh Solid bowl centrifuge with drying of the solids cake
JP2012236184A (en) * 2011-04-25 2012-12-06 Ameroido Nippon Service Sha:Kk Centrifugal separation device
JP3191304U (en) * 2014-02-19 2014-06-19 株式会社クラレ centrifuge

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WO2018133908A1 (en) 2018-07-26
DK201700006U3 (en) 2018-05-01

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