US3275156A - Strainer of the centrifugal type - Google Patents

Strainer of the centrifugal type Download PDF

Info

Publication number
US3275156A
US3275156A US332575A US33257563A US3275156A US 3275156 A US3275156 A US 3275156A US 332575 A US332575 A US 332575A US 33257563 A US33257563 A US 33257563A US 3275156 A US3275156 A US 3275156A
Authority
US
United States
Prior art keywords
blades
strainer
shaft
rotor shaft
paddles
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
US332575A
Inventor
Valtanen Seppo Olavi
Punttila Olli Juhani
Sjolund Ulf Viking
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.)
Ahlstrom Corp
Original Assignee
Ahlstrom Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ahlstrom Corp filed Critical Ahlstrom Corp
Priority to US332575A priority Critical patent/US3275156A/en
Application granted granted Critical
Publication of US3275156A publication Critical patent/US3275156A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/11—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
    • B01D29/117—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements arranged for outward flow filtration
    • B01D29/118—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements arranged for outward flow filtration open-ended
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/76—Handling the filter cake in the filter for purposes other than for regenerating
    • B01D29/78—Handling the filter cake in the filter for purposes other than for regenerating for washing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/76—Handling the filter cake in the filter for purposes other than for regenerating
    • B01D29/86—Retarding cake deposition on the filter during the filtration period, e.g. using stirrers

Definitions

  • the following invention consists of a device in a strainer of the centrifugal type, particularly one used for the further alluviation of fibres such as cellulose pulps.
  • pulp After it enters a centrifugal strainer, pulp is thrust by the centrifugal force towards the strainer drum surrounding the rotor, whereupon some of the fibres go direct through holes in the screen wall and the rest form a layer consisting of impurities, coarse fibres and fine fibres which cannot flow through the fibre sheet.
  • blades moving along the inner surface of the strainer drum have been used, among other devices, to create pulsations which clean the screen wall.
  • Another method of separating utilizable fibres from the layer is to dilute those which can be diluted by adding water or fresh pulp. Alluviation water can be supplied through holes in a hollow-bored rotor shaft, for example.
  • the object of the invention is to eliminate the above disadvantages by means of a device in a strainer of the centrifugal type, particularly one used for the further alluviation of fibres, such as cellulose pulps.
  • the said strainer has a rotating, hollow rotor shaft furnished with holes and with blades fastened to the shaft and running along it in a radial direction.
  • the principal characteristic of the device is that the alluviation water and/ or pulp that enters through the rotor shaft and its holes is made to flow along the front face of each blade, as viewed in the direction of rotation, and that one the front face at the outer end of each blade near the inner surface of the strainer drum there is a detachable paddle which admits the alluviation water and/or incoming pulp on to the back face on the blade.
  • the paddles attached to the rotor blades create a turbulence in the layer of fibres on the strainer drum, simultaneously causing a difference in pressure between their front and back faces, so that the alluviation water and/ or incoming pulp is effectively mixed with and alluviates the fibre layer.
  • FIG. 1 is a longitudinal section of the strainer.
  • FIGS. 2 and 3 are cross sections along lines A-A and 'BB in FIG. 1.
  • the rotor shaft 1 which is bored hollow longitudinally in order to supply alluviation water in a manner which need not be described here, is furnished with holes 2. Pulp is fed in through an inlet 3 and, after it has been strained, it passes round the screen wall 4 and leaves through an outlet 5, while the rejected products (impurities and coarser pulp) leave through another outlet 6. Alluviation water flows through the shaft holes 2, which open on to the front faces of the rotor blades 7, and is thrust out along said front faces by the centrifugal force.
  • Detachable paddles 8 (FIG.
  • Incoming pulp enters the rotor through the inlet 3. Some of the pulp in the rotor is able to flow in the direction of the arrows 10 towards the periphery of the rotor, and some or all of it passes through a cylindrical tube 11 around the shaft in the direction of arrows 12 (FIG. 1).
  • the tube 11 is furnished with slits 12 (FIG. 3) along the front side of the rotor blades, through which the pulp is thrust by the centrifugal force and from there along the rotor blades towards the periphery, where the layer on pulp on the strainer drum undergoes further alluviation.
  • the paddles 8 and slits 9 can either be as long as or shorter than the rotor bladesextending from the back end of the strainer to the baflle plate 13, for example.
  • the width of the slits 9 can be adjustable and the profile of the paddles can vary at different points along the strainer.
  • a device ensures effective cleansing of the screen wall with a minimum of alluviation water and offers unlimited possibilities for adapting the strainer to different conditions of operation by changing the paddles.
  • the invention provides greater capacity for less power consumption than conventional designs.
  • a strainer of the centrifugal type adapted for the further alluviation of fibers such as cellulose pulps comprising an elongated cylindrical perforated strainer drum, a rotatable hollow rotor shaft having a bore therein mounted coaxially of the strainer drum, means to rotate said shaft, means to admit a liquid suspension of fibers into the bore in the hollow rotor shaft, said rotor shaft having a plurality of holes through the wall thereof, a plurality of generally radially extending blades aflixed to the rotor shaft to rotate therewith within the strainer, said blades being so disposed on the shaft that the holes in the wall of the shaft lie close to and in advance of the forward faces of the respective blades which lead in the direction of rotation of the rotor shaft and blades, and a paddle mounted on the radially outer end of each of the blades, the paddles forming general prolongations of the respective blades and having their outer ends closely confronting but spaced somewhat from the inner surface of the strainer drum, the
  • openings at the zone of connection between the radially outer ends of the blades and said paddles are in the form of slits disposed at an acute angle relative to the main extent of the blades and inclined in a direction radially outwardly and rearwardly thereto with respect to the direction of rotation of the shaft and blades.
  • a strainer as claimed in claim 1 wherein said References Cited by the Examiner paddles have an axial length which is substantially the UNITED STATES PATENTS same as that of the blades and strainer, and both the blades ancll padglles lie radially within the strainer through- 5 if z i fi' ellgt 3,149,067 9/1964 Cannon et al. 210 415 X 4.

Description

pt. 27, 1966 s. o. VALTANEN ETAL 3,275,156
STRAINER OF THE CENTRIFUGAL TYPE Filed Dec. 23, 1963 2 Sheets-Sheet 1 Sept. 27, 1956 s. o. VALTANEN ETAL 3,275,156
STRAINER OF THE CENTRIFUGAL TYPE Filed Dec. 25, 1963 2 Sheets-Sheet 2 United States Patent 3,275,156 STRAINER OF THE CENTRIFUGAL TYPE Seppo Olavi Valtanen, Olli Juhani Punttila, and Ulf Viking Sjiilund, all of Karlinla, Finland, assignors to A.
Alilstriim Osakeylititi, Karhula, Finland, :1 company of Finland Filed Dec. 23, 1963, Ser. No. 332,575 4 Claims. (Cl. 210-415) The following invention consists of a device in a strainer of the centrifugal type, particularly one used for the further alluviation of fibres such as cellulose pulps.
After it enters a centrifugal strainer, pulp is thrust by the centrifugal force towards the strainer drum surrounding the rotor, whereupon some of the fibres go direct through holes in the screen wall and the rest form a layer consisting of impurities, coarse fibres and fine fibres which cannot flow through the fibre sheet. To break up this layer, blades moving along the inner surface of the strainer drum have been used, among other devices, to create pulsations which clean the screen wall. Another method of separating utilizable fibres from the layer is to dilute those which can be diluted by adding water or fresh pulp. Alluviation water can be supplied through holes in a hollow-bored rotor shaft, for example. Such devices, in which the alluviation water flows to the periphery of the rotor through holes in the rotor shaft and from there through two plates which together form a rotor blade, are prior known. One of the drawbacks of this is that the alluviation water flows through the slit between the plates at a relatively low speed, so that the slit easily clogs up again, since the alluviation water usually consists of 0- water containing fibres. O-water is a term designating white water, that is, circulation of water (back water) of a paper factory containing small quantities of short fibres. The double blade adds weight to the rotor and makes it diflicult to clean.
The object of the invention is to eliminate the above disadvantages by means of a device in a strainer of the centrifugal type, particularly one used for the further alluviation of fibres, such as cellulose pulps. The said strainer has a rotating, hollow rotor shaft furnished with holes and with blades fastened to the shaft and running along it in a radial direction. The principal characteristic of the device is that the alluviation water and/ or pulp that enters through the rotor shaft and its holes is made to flow along the front face of each blade, as viewed in the direction of rotation, and that one the front face at the outer end of each blade near the inner surface of the strainer drum there is a detachable paddle which admits the alluviation water and/or incoming pulp on to the back face on the blade.
In the device according to the invention, the paddles attached to the rotor blades create a turbulence in the layer of fibres on the strainer drum, simultaneously causing a difference in pressure between their front and back faces, so that the alluviation water and/ or incoming pulp is effectively mixed with and alluviates the fibre layer.
Greater detail is shown in the accompanying drawings, which illustrate one embodiment of the device, adapted for a centrifugal strainer.
FIG. 1 is a longitudinal section of the strainer.
FIGS. 2 and 3 are cross sections along lines A-A and 'BB in FIG. 1.
In FIG. 1 the rotor shaft 1, which is bored hollow longitudinally in order to supply alluviation water in a manner which need not be described here, is furnished with holes 2. Pulp is fed in through an inlet 3 and, after it has been strained, it passes round the screen wall 4 and leaves through an outlet 5, while the rejected products (impurities and coarser pulp) leave through another outlet 6. Alluviation water flows through the shaft holes 2, which open on to the front faces of the rotor blades 7, and is thrust out along said front faces by the centrifugal force. Detachable paddles 8 (FIG. 2), fastened to the ends of the rotor blades 7 are shaped in such a way and placed at such a distance from the strainer drum that they create a turbulence behind them in the layer of pulp on the drum, causing a sufficient difference in pressure between their front and back faces for the alluviation water to flow through slits 9, which open on to the back faces of the paddles 8. These paddles 8 are interchangeable, so that a suitable shape of paddle can be selected for every condition of operation (quality and consistency of pulp).
Incoming pulp enters the rotor through the inlet 3. Some of the pulp in the rotor is able to flow in the direction of the arrows 10 towards the periphery of the rotor, and some or all of it passes through a cylindrical tube 11 around the shaft in the direction of arrows 12 (FIG. 1). The tube 11 is furnished with slits 12 (FIG. 3) along the front side of the rotor blades, through which the pulp is thrust by the centrifugal force and from there along the rotor blades towards the periphery, where the layer on pulp on the strainer drum undergoes further alluviation.
The paddles 8 and slits 9 can either be as long as or shorter than the rotor bladesextending from the back end of the strainer to the baflle plate 13, for example. The width of the slits 9 can be adjustable and the profile of the paddles can vary at different points along the strainer.
A device according to the invention ensures effective cleansing of the screen wall with a minimum of alluviation water and offers unlimited possibilities for adapting the strainer to different conditions of operation by changing the paddles. The invention provides greater capacity for less power consumption than conventional designs.
What we claim is:
1. A strainer of the centrifugal type adapted for the further alluviation of fibers such as cellulose pulps, comprising an elongated cylindrical perforated strainer drum, a rotatable hollow rotor shaft having a bore therein mounted coaxially of the strainer drum, means to rotate said shaft, means to admit a liquid suspension of fibers into the bore in the hollow rotor shaft, said rotor shaft having a plurality of holes through the wall thereof, a plurality of generally radially extending blades aflixed to the rotor shaft to rotate therewith within the strainer, said blades being so disposed on the shaft that the holes in the wall of the shaft lie close to and in advance of the forward faces of the respective blades which lead in the direction of rotation of the rotor shaft and blades, and a paddle mounted on the radially outer end of each of the blades, the paddles forming general prolongations of the respective blades and having their outer ends closely confronting but spaced somewhat from the inner surface of the strainer drum, the paddles and blades at the zone of connection therebetween presenting openings therethrough whereby said liquid suspension is caused by centrifugal force to flow along the forward faces of the blades, out through said openings at the connections between the outer ends of the blades and the paddles, and into contact with fibers collected on the inner surface of the strainer, in order further to alluviate such collected fibers.
2. A strainer as claimed in claim 1, wherein said openings at the zone of connection between the radially outer ends of the blades and said paddles are in the form of slits disposed at an acute angle relative to the main extent of the blades and inclined in a direction radially outwardly and rearwardly thereto with respect to the direction of rotation of the shaft and blades.
3 4 3. A strainer as claimed in claim 1, wherein said References Cited by the Examiner paddles have an axial length which is substantially the UNITED STATES PATENTS same as that of the blades and strainer, and both the blades ancll padglles lie radially within the strainer through- 5 if z i fi' ellgt 3,149,067 9/1964 Cannon et al. 210 415 X 4. A strainer as claimed in claim 1, comprising a housing surrounding and radially spaced from the strainer, REUBEN FRIEDMAN, Primary Examiner.
and liquid discharge means connected to the housing. L DECESARE Assistant Examiner

Claims (1)

1. A STRAINER OF THE CENTRIFUGAL TYPE ADAPTED FOR THE FURTHER ALLUVIATION OF FIBERS SUCH AS CELLULOSE PULPS, COMPRISING AN ELONGATED CYLINDRICAL PERFORATED STRAINER DRUM, A ROTATABLE HOLLOW ROTOR SHAFT HAVING A BORE THEREIN MOUNTED COAXIALLY OF THE STRAINER DRUM, MEANS TO ROTATE SAID SHAFT, MEANS TO ADMIT A LIQUID SUSPENSION OF FIBERS INTO THE BORE IN THE HOLLOW ROTOR SHAFT, SAID ROTOR SHAFT HAVING A PLURALITY OF HOLES THROUGH THE WALL THEREOF, A PLURALITY OF GENERALLY RADIALLY EXTENDING BLADES AFFIXED TO THE ROTOR SHAFT TO ROTATE THEREWITH WITHIN THE STRAINER, SAID BLADES BEING SO DISPOSED ON THE SHAFT THAT THE HOLES IN THE WALL OF THE SHAFT LIE CLOSE TO AND IN ADVANCE OF THE FORWARD FACES OF THE RESPECTIVE BLADES WHICH LEAD IN THE DIRECTION OF ROTATION OF THE ROTOR SHAFT AND BLADES, AND IN PADDLE MOUNTED ON THE RADIALLY OUTER END OF EACH OF THE BLADES, THE PADDLES FORMING GENERAL PROLONGATIONS OF THE RESPECTIVE BLADES AND HAVING THEIR OUTER ENDS CLOSELY CONFRONTING BUT SPACED SOMEWHAT FROM THE INNER SURFACE OF THE STRAINER DRUM, THE PADDLES AND BLADES AT THE ZONE OF CONNECTION THEREBETWEEN PRESENTING OPENINGS THERETHROUGH WHEREBY SAID LIQUID SUSPENSION IS CAUSED BY CENTRIFUGAL FORCE TO FLOW ALONG THE FORWARD FACES OF THE BLADES, OUT THROUGH SAID OPENINGS AT THE CONNECTIONS BETWEEN THE OUTER ENDS OF THE BLADES AND THE PADDLES, AND INTO CONTACT WITH FIBERS COLLECTED ON THE INNER SURFACE OF THE STRAINER, IN ORDER FURTHER TO ALLUVIATE SUCH COLLECTED FIBERS.
US332575A 1963-12-23 1963-12-23 Strainer of the centrifugal type Expired - Lifetime US3275156A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US332575A US3275156A (en) 1963-12-23 1963-12-23 Strainer of the centrifugal type

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US332575A US3275156A (en) 1963-12-23 1963-12-23 Strainer of the centrifugal type

Publications (1)

Publication Number Publication Date
US3275156A true US3275156A (en) 1966-09-27

Family

ID=23298844

Family Applications (1)

Application Number Title Priority Date Filing Date
US332575A Expired - Lifetime US3275156A (en) 1963-12-23 1963-12-23 Strainer of the centrifugal type

Country Status (1)

Country Link
US (1) US3275156A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3735873A (en) * 1969-06-10 1973-05-29 Sunds Ab Sundsvall Apparatus for screening aqueous suspensions, preferably fiber stock and/or fiber-pulp suspensions
US4178246A (en) * 1977-05-31 1979-12-11 Max Klein Separator for discrete solids from liquids
US4328096A (en) * 1980-03-17 1982-05-04 The Black Clawson Company Dual flow screening apparatus
US4697982A (en) * 1986-03-13 1987-10-06 Uniweld Inc. Rotary pulp screen of the horizontal type having pulp stock feed at different axial positions on the screen

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2899064A (en) * 1959-08-11 Rotary pulp screens
US3082874A (en) * 1959-05-12 1963-03-26 Beloit Iron Works Stock screen
US3149067A (en) * 1962-08-23 1964-09-15 Bird Machine Co Screening device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2899064A (en) * 1959-08-11 Rotary pulp screens
US3082874A (en) * 1959-05-12 1963-03-26 Beloit Iron Works Stock screen
US3149067A (en) * 1962-08-23 1964-09-15 Bird Machine Co Screening device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3735873A (en) * 1969-06-10 1973-05-29 Sunds Ab Sundsvall Apparatus for screening aqueous suspensions, preferably fiber stock and/or fiber-pulp suspensions
US4178246A (en) * 1977-05-31 1979-12-11 Max Klein Separator for discrete solids from liquids
US4328096A (en) * 1980-03-17 1982-05-04 The Black Clawson Company Dual flow screening apparatus
US4697982A (en) * 1986-03-13 1987-10-06 Uniweld Inc. Rotary pulp screen of the horizontal type having pulp stock feed at different axial positions on the screen

Similar Documents

Publication Publication Date Title
CA1286637C (en) Screening apparatus for fiber suspensions
US3713541A (en) Screening machine with slotted screen
EP0042742B1 (en) Apparatus for screening paper fiber stock
GB1598961A (en) Screening paper-making stock
US3581903A (en) Separator for paper pulp suspensions
US4699324A (en) Combined screening and reject reduction
US3849302A (en) Method and apparatus for screening paper fiber stock
US2737857A (en) Hydraulic apparatus
US3865243A (en) Pressure strainer device
US4396502A (en) Screening apparatus for a papermaking machine
FI59272B (en) SKIVRAFFINOER
US4383918A (en) High turbulence screen
US3275156A (en) Strainer of the centrifugal type
US4105543A (en) Method for screening paper fiber stock
US4136018A (en) Vortex separator with coaxial inlet and lightweight reject pipelines
US2908390A (en) Apparatus for screening pulp
SE461990B (en) METHOD AND APPARATUS FOR WASHING PAPER Pulp
US2845848A (en) Apparatus for screening pulp
US4316768A (en) Pulse free stock screen and combination pump
US4213823A (en) Paper making machine screen with staggered foils
JPH0253990A (en) Selector for fiber cellulose fiber suspension
CA1180686A (en) Paper making stock screening apparatus incorporating circular apertured cylindrical pressure screen
GB1188726A (en) Screening Apparatus
US2752828A (en) Screen for paper stock
US2899064A (en) Rotary pulp screens