Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/02—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents
  • D21C9/06—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents in filters ; Washing of concentrated pulp, e.g. pulp mats, on filtering surfaces
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D33/00—Filters with filtering elements which move during the filtering operation
  • B01D33/06—Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums
  • B01D33/067—Construction of the filtering drums, e.g. mounting or sealing arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
  • F16J15/3204—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
  • F16J15/3204—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip
  • F16J15/3232—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip having two or more lips
  • F16J15/3236—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip having two or more lips with at least one lip for each surface, e.g. U-cup packings

Definitions

• the present invention relates to a pulp filter or a pulp washer and particularly to a sealing for use in the sealing of the rotating member thereof.
• the sealing solves well for example problems associated with the sealing of the large-diameter parts of drums used in large wash and filter cylinders of the wood processing industry.
• the sealing according to the invention is well applicable, for example, also in the sealing of the shafts of drum filters, disc filters and other corresponding filters of the wood processing industry.
• the solution comprises a sealing member and a propelling member to be disposed and clamped with a clamping sleeve in a sealing box.
• the sealing member is placed in the sealing box so that it lies against the surface of a rotating drum.
• the propelling member on the other hand is supported against the radially outer wall of the sealing box.
• the sealing member in turn has a T- formed cross section so that the stem portion of the T is disposed in a groove of corresponding size in the propelling member.
• An essential feature of the sealing member is that the friction between the sealing member and the propelling member is clearly higher than the friction between the sealing member and the surface to be sealed.
• the sealing member is preferably made of plastics material the friction coefficient of which is low and the chemical and temperature resistance are good.
• the width of the sealing surface in the axial direction is preferably a little smaller than the width of the propelling member so that when the propelling member/members is/are compressed with the clamping sleeve, neither the sleeve nor the back wall can get in touch with the sealing member.
• the sealing works so that when the sealing element or pair is pressed to its place in the sealing box around the rotating drum the propelling member, which preferably is made of elastic rubber material, is compressed in the axial direction and at the same time tends to expand in the radial direction pressing the sealing member tightly against the rotating piece.
• the sealing according to the invention can, in a single application, replace two braided sealing rope turns but several sealing elements may be used side by side if desired.
• the propelling member is formed of an annular rubber tube and the sealing member is pressed against the surface of the drum by pressure introduced inside the rubber tube.
• the ring used as the sealing member made of teflon or corresponding relatively hard plastics material.
• the sealing member while pressed against the surface of the drum creates quite a high force which is revealed, in addition to the heating of the sealing and thus loading and wearing of it, also by wear of the drum surface. The result is in any case a decreased sealing capacity.
• all the above sealing methods require a special sealing water arrangement bringing clean water to the sealings in order to prevent increase of the friction between the sealing and the surface to be sealed and to prevent heating and breaking down of the sealing. In a way, this is lubrication of the sealing via a separate liquid inlet.
• Some of the above approaches require also a separate propellant arrangement for providing pressure in the propelling member, either pressurized air or pressurized liquid.
• the present invention strives for avoiding the disadvantages of the sealings mentioned above by means of a sealing which has a remarkably longer life than the prior art approaches and the price of which is only a fraction of that of the prior art arrangements.
• the arrangement according to the invention provides for example the following advantages over the prior art: • the sealing member cannot rotate with the drum;
• the pulp space may be completely filled also with pulps which are more difficult to treat and the washing becomes more efficient;
• the sealing according to the invention serves both as the sealing of the filter element of the washer or the filter and the sealing of their shaft.
• Fig. 1 illustrates a preferred embodiment of the sealing according to the invention
• Fig. 2 illustrates another preferred embodiment of the sealing according to the invention
• Fig. 3 illustrates a third preferred embodiment of the sealing according to the invention
• Fig. 4 illustrates a fourth preferred embodiment of the sealing according to the invention.
• Fig. 1 illustrates one end of a so-called DRUMDISPLACER ® washer, partly in section.
• the washer in question comprises, as far as the components visible in the figure are concerned, a stationary outer shell 10, a wash liquid feed chamber 12 disposed inside the shell, its end ring 14, and stationary substantially cylindrical perforated plate 16 defining it at the wall by the shaft.
• the washer further comprises a washing cylinder disposed at a distance inside the perforated plate 16 mentioned, the diameter of the cylinder being of the order of 3 - 5 m and the length 3 - 10 m and the surface of the cylinder being formed correspondingly of a substantially cylindrical perforated plate 18. Between the perforated plate 16 defining the wash liquid feed chamber 12 and the perforated drum plate 18.
• the washer further includes sealing means for the drum, the sealing means comprising a sealing box 26 defined by the end ring 14 of the feed chamber 12, or a corresponding member, by a sealing box outer ring 28 having a surface 28S to be sealed, by a counter member 30 and the drum end cylinder 22 having a surface 22S to be sealed, and a sealing disposed in the box.
• the sealing comprises a bottom ring 32, which may be made of metal, for example steel, or for example of solid rubber, resting against the counter member 30, and a lip sealing 34 provided against the ring.
• the function of the sealing box 26 at the end of the DRUMDISPLACER ® washer is to seal the pressurized pulp space 20 relative to the outside of the washer. In other words, the objective is to prevent both the pulp and the wash liquid used in washing the pulp from leaking out via the end of the washer.
• this objective is reached by using a lip sealing 34 in the sealing housing 26 so that pressure medium is brought to the pressurized side of the sealing box 26, i.e. to the side open towards the pulp space 20, which medium presses the lips of the sealing 34 against the surface 22S and 28S to be sealed.
• the medium in question is preferably washing liquid used in washing the pulp.
• the pressure medium is introduced to the sealing box at a pressure a little higher than the pressure prevailing in the space 20 so that the flow in the slot 36 between the end ring 14 and the end cylinder 22 takes place from the sealing box 26 toward the pulp space 20. This ensures that fibers cannot penetrate from the pulp space 20 via the slot 36 to the sealing box 26.
• An essential feature of the invention is that sealing of the drum end is provided by arranging the liquid flow in the slot 36 between the end ring 14 and the end cylinder 22 to take place from the sealing box or corresponding means towards the pulp space. This is effected by introducing liquid to the sealing box at a pressure higher than the pressure in the pulp space 20. Further, the volume of liquid flowing via the slot to the pulp space 20 may be controlled by appropriate adjustment of the slot 36, particularly in relation to the pressures in the sealing box and the pulp space, or the pressure difference.
• Fig. 1 also illustrates how washing liquid Wl may be introduced to the feed chamber 12 via a duct 38.
• the duct 38 has been provided with a branch 40 bringing wash liquid to the sealing box 26 to serve as pressure medium.
• the branch has preferably been provided with a pressure increasing pump 42, to ensure a pressure difference between the feed chamber 12 and the sealing box 26.
• the lip sealing 34 has been secured to the bottom ring 32 or through it to the counter member 30 with for example screws or corresponding means.
• Fig. 2 illustrates a sealing arrangement according to another preferred embodiment of the invention in which the counter member 30 has been sealed with an O ring 50 relative to the surface 28S and in which a one-sided lip sealing 54, the lip of which is disposed against one of the surfaces to be sealed 22 S, has been secured (in the embodiment illustrated with screws although also other securing means are applicable) to the surface of the counter member 30 facing the sealing box 26.
• the O ring seals the sealing box 26 between the components 28 and 30, which are stationary in relation to each other
• the lip sealing 54 seals between the stationery counter member 30 and the end cylinder 22 of the rotating drum.
• the above design works also as such, at least if pressure medium is introduced to the sealing box 26 as illustrated in Fig. 1, which is quite possible.
• FIG. 2 has been completed by providing an intermediate ring 56, preferably secured with bolts in the sealing box 26 in its end ring 14 at the side facing the pulp space 20 for sealing the slot 36 between the end ring 14 and the end cylinder 22.
• the function of the intermediate ring 56 mentioned is primarily to adjust the liquid flow from the sealing box or corresponding space to the pulp space to be appropriate, and secondarily to prevent fibers from penetrating from the pulp space 20 to the sealing box 26.
• the use of the intermediate ring makes possible considering the special properties of each washer.
• the various pressure differences between the pulp space and the sealing box may be better taken into account by adjusting the slot mentioned by means of for example intermediate rings of different sizes without having to interfere with the dimensioning of the mechanical apparatus, such as the end ring 14, of the washer.
• a flushing nozzle 58 provided to open in the slot 36 and to rotate with the drum, through which flushing water is sprayed at a relatively high pressure to the slot 36 in order to blow out fibers which possibly have penetrated into the slot.
• the design of the nozzle 58 is preferably such that it directs a rotating flushing water jet into the slot 36, whereby the jet washes also the fibers drifted into the area between the nozzle 58 and the intermediate ring 56 off from the slot 36.
• Figure 3 illustrates a sealing arrangement according to a third embodiment of the invention in which the counter member 30 has been sealed with an O ring 50 relative to the surface 28S, as in the previous embodiment.
• the one-sided lip sealing 64 has been secured, preferably with bolts, to the end cylinder 22, i.e. the lip sealing 64 has been secured to a rotating member.
• the lip of the lip sealing 64 rests against the surface 30S of the counter member 30 facing the sealing box 26.
• a wearing ring 66 may be provided in the surface 3 OS of the counter member 30 and the material of the wearing ring may have better wear resistance properties than the material of the counter member 30.
• the ring 66 may also be replaceable whereby both the elements taking care of the sealing are easy to replace with new ones, for example in a situation where material which wears out the sealing surfaces has flown into the sealing box during unusual operating conditions or because of false running.
• a special wearing surface may be used which is in contact with the lip of the lip sealing and which has either gliding properties or wearing resistance better than the base material.
• the wearing ring or the wearing surface may of course be replaced by treating the base material so that its wearing and glide properties are improved.
• Figure 3 also illustrates how a pressure medium duct 40 may be connected to the sealing box 26, as illustrated in Fig.
• FIG. 1 The figure further illustrates an intermediate ring 56 as in Fig. 2 although it may be dispensed with and the liquid flow between the sealing box and the pulp space may be arranged appropriate also in the way illustrated in Fig. 1.
• the pressure of the pressure medium, preferably liquid, introduced into the sealing box 26 is the same as the pressure in the pulp space the use of the intermediate ring 56 is justified.
• Figure 4 illustrates yet another embodiment of the invention in which the flushing of the slot 36 between the end ring 14 and the end cylinder 22 has been arranged in a slightly different way than in the embodiments described above.
• the sealing of the sealing box 26 itself may be provided in practice by any method described in the embodiments above or in fact in any way within the scope of protection of the invention; thus in Fig. 4, the sealing method illustrated in Fig. 2 has been used, as an example.
• pressure medium preferably liquid and more preferably pulp washing liquid
• sealing water mentioned in association with the previous embodiments is introduces via duct 40 and it is used to press the lip of the lip sealing 54 against the surface 22S to be sealed.
• partition wall 72 provided in the sealing box 26, which wall defines a space 74 at the sealing box 26 end adjacent the pulp space 20.
• a flushing duct 76 leads into the space 74 either in the way illustrated in the figure through the partition wall 72 or directly through the outer ring 28 into the space 74.
• the partition wall 72 has been sealed relative to the sealing box at both its ends at the sealing box 26 periphery.
• the partition wall has preferably been secured to the outer ring 28 while, for example, a rubber washer 78 seals the partition wall 72 relative to the surface 28S.
• the inner edge of the partition wall 72 is sealed by a lip 80 dragging along the surface 22S.
• the target of the embodiment illustrated in the drawing is to create in the sealing box 26 and the space 74 conditions under which the slot 36 remains clean without the cleaning arrangements illustrated in the previous figures.
• the idea is to introduce liquid into the space 74 at a pressure higher than the pressure prevailing in the pulp space 20. Then the liquid flow in the slot 36 takes place from the sealing box 26 to the pulp space 20. Liquid is introduced via the duct 40 to another section of the sealing box 26 at a lower pressure but by dimensioning the 10
• the lip sealing Materials usable as the lip sealing are EPDM rubber and other corresponding rubber materials.
• the sealing, a well as the bottom ring possibly used with it, is as uniform as possible. In other words, the structure should have as few joints as possible. Due to the treatment of the sealing, a solution has been tested, in which the sealing comprises two sealing strips of equal length; thus the joints are located at the opposites sides of the drum periphery.
• the sealing according to the present invention is applicable in addition to the sealing of the filter element of the drum washer, i.e. sealing of the end of the drum washer surface, also to the sealing of the shafts of for example drum or disc filters.
• the object to be sealed is an object having a large diameter, often more than 500 mm, relative to a fiber suspension having a fairly low pressure.
• the applications described in association with the above embodiments may be modified to serve as shaft sealing by replacing the rotating drum of the embodiments with the rotating shaft of the filter in question.
• the filter or the washer may also be for example a disc filter comprising discs having wire surfaces or being otherwise water permeable, disposed side by side on a horizontal shaft.
• the shaft with the discs has been placed in a vat so that fiber suspension or other suspension to be filtered in the vat covers the discs at least nearly up to the shaft. In some cases the suspension covers the discs even up to a level above the shaft. 11
• the drum filter in turn may be of the same type as the drum washer described above but the structure of the filter may be remarkably simpler.
• a drum filter is formed of a wire surface secured at its ends to a horizontal shaft, or of a perforated cylinder disposed in a vat containing fiber suspension or some other suspension to be filtered.
• the filter elements i.e. discs comprising in most cases adjacent sections, or the drum are supported via the shaft onto the ends of the vat whereby the shaft is mounted on bearings to the ends of the vat and also sealing relative to the end of the vat.
• the washers are atmospheric; thus the pressure directed to the sealing comes from the hydrostatic pressure of the suspension, only. In other words, the pressure of the liquid used for the sealing need not be much higher than atmospheric and it still is capable of preventing the suspension from flowing into the sealing space.
• Figure 5 illustrates a shaft sealing according to a preferred embodiment of the invention.
• Reference number 28 refers to the outer ring of a sealing box 26 inside which there is a counter member 30 sealed by an O ring 50.
• the rotating means to be sealed, in this embodiment the shaft has been assigned the reference number 82.
• the sealing members 84 and 86 between the counter member 30 and the end ring 14 have been separated from each other by a spacer 88 which is of the same type as the so-called water ring in the so-called braided sealings.
• the spacer 88 is a ring having an inlet opening at least at the duct 40 for feeding the sealing liquid into the sealing box 26.
• the sealing illustrated in Fig. 5 corresponds to the disclosure of Figures 1 - 4.
• drum sealing may be of another type than the lip sealing; in some cases the use of a conventional O ring is very suitable.
• all sealing arrangements which comprise the solution defined in the first patent claim are included in the scope of protection of the present invention.
• the approach according to the invention is well suitable for use also outside the wood processing industry in applications in which large, preferably cylindrical surfaces moving in relation to each other have to be sealed relative to each other.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Paper (AREA)
• Sealing With Elastic Sealing Lips (AREA)

Applications Claiming Priority (5)

Publications (1)

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Family Applications (1)

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• 1999
  • 1999-02-01 FI FI990182A patent/FI990182A/fi unknown
  • 1999-03-09 CA CA002323049A patent/CA2323049A1/en not_active Abandoned
  • 1999-03-09 PL PL99342808A patent/PL342808A1/xx unknown
  • 1999-03-09 CN CN99805951A patent/CN1302219A/zh active Pending
  • 1999-03-09 NZ NZ506876A patent/NZ506876A/xx unknown
  • 1999-03-09 WO PCT/FI1999/000183 patent/WO1999046025A1/en not_active Application Discontinuation
  • 1999-03-09 JP JP2000535434A patent/JP2002506143A/ja active Pending
  • 1999-03-09 EP EP99907639A patent/EP1069934A1/de not_active Withdrawn
• 2000
  • 2000-09-11 NO NO20004529A patent/NO20004529L/no not_active Application Discontinuation

Non-Patent Citations (1)

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