GB2056904A

GB2056904A - Making sleeves by accretion

Info

Publication number: GB2056904A
Application number: GB8027612A
Authority: GB
Original assignee: Foseco Trading AG
Current assignee: Foseco Trading AG
Priority date: 1979-08-23
Filing date: 1980-08-26
Publication date: 1981-03-25
Also published as: GB2056904B

Abstract

Sleeves are made from a slurry, e.g. an aqueous slurry of refractory fibres and binder, by feeding it to an axially extending surface of a tubular member 2, drawing the slurry liquid through perforations in the surface to deposit the slurry solids on the surface, reciprocating the member 2 axially to resist adhesion of the deposited material, moving the material along the surface and through a sheath 8 and separating the formed sleeve 22 from the member and sheath. Apparatus for use in the method comprises a slurry holding chamber 1, the axially reciprocable tubular member 2 extending across the chamber and, extending beyond one sidewall of the chamber, the sheath 8 located about a portion of the tubular member with a clearance 9 in between. Sleeves of use in the metallurgical industry can be made. <IMAGE>

Description

SPECIFICATION Sleeves This invention concerns sleeves of material which are formed from a slurry by deposition of solids therefrom.

There is a need in the metallurgical and other industries for a simple, cheap and reliable way of making sleeves of material from a slurry. It is an object of this invention to fulfil that need.

According to the invention, a method of making a sleeve of material from a slurry of solids in a liquid carrier comprises feeding the slurry to an axially extending surface of a tubular member, drawing the liquid component of the slurry through perforations in the axially extending surface of the member to deposit the solids component of the slurry on that surface, causing the member to reciprocate axially to resist adhesion of the deposited material to the member, moving the deposited material along the axially extending surface of the member and through a sheath and separating the formed sleeve from the member and the sheath.

The slurry may typically be an aqueous slurry of refractory fibres and a binding agent.

Preferably the deposited material is caused to move along the axially extending surface of the member by arranging for the member to reciprocate. with a motion which is faster in one direction than in the other direction.

The tubular member preferably has surface grooves which run axially of the member to guide the deposited material along the surface of the member on which it is deposited. The cross-sectional shape of the tubular member may be circular or otherwise and the size of the tubular member may or may not be constant along its length. The interior of the member need not be entirely hollow as long as liquid passing through the perforations in the surface can be conducted away from the member. By 'axially extending surface' of the member is meant either of the surfaces extending generally parallel to the axis of the tubular member.

The sheath is most preferably arranged to oscillate along a rotary path about the axis of the tubular member to resist adhesion of the deposited material to the sheath.

The invention includes a sleeve when made by the method.

The invention further includes apparatus for use in the method comprising: a chamber for holding a slurry of solids in a liquid, the chamber having opposite side walls, a tubular member, having perfora tions in an axially extending surface thereof, extending across the chamber and, extend ing beyond one sidewall, a sheath located about a portion of the tubular member with a clearance in between, means for reciprocating the tubular member between the sidewalls and means for drawing a vacuum in the cham ber, whereby when a vacuum is drawn in the chamber liquid egresses from the chamber via the tubular member and solids are deposited thereon and reciprocation of the member urges the deposited solids out of the chamber via the clearance between the member and the sheath.

Preferably the sheath is arranged to oscillate along a rotary path. Preferably fingers extend from the sheath into the chamber to agitate the slurry.

Preferably the tubular member is arranged to move more slowly on its stroke towards the sheath than away therefrom.

The invention will now be described by way of example, with reference to the accompanying diagrammatic drawings, in which Figure 1 is a longitudinal section through an apparatus for performing the method of the invention, Figure 2 is an end elevation of the apparatus, and Figure 3 is a detail A of the apparatus illustrated in Fig. 1.

The apparatus comprises a slurry chamber 1, a tubular member 2 serving as a former and a vacuum chamber 3. The slurry chamber 1 and the vacuum chamber 3 share a common wall 4 and the tubular member 2 extends through both chambers and through the common wall 4, in a sealed manner.

The slurry chamber 1 has an inlet 5 and an outlet 6 for slurry. The chamber wall 7 which is opposite the common wall 4, receives a sheath 8 which is located about the tubular member 2 with an annular clearance 9 defined between the sheath 8 and the member 2 for the definition of a sleeve 22. An arm 10 extends radially from the sheath 8 external to the slurry chamber 1. The remote end of the arm 10 is pivotally connected to the piston rod 11 of a piston/cylinder arrangement 1 2. A number of fingers 1 3 extend from the sheath 8 into the slurry chamber 1 for the purpose of agitating slurry within the chamber 1.

As shown in Fig. 3, the tubular member 2 comprises an outer portion 1 4 and an inner portion 1 5. A number of parallel grooves 1 6 run longitudinally in the outer face of the member, and in the inner face of the outer portion 1 4 run a number of circumferential channels 17. The grooves 16 intercommunicate with the channels 1 7. Four passageways 1 8 run longitudinally in the outer face of the inner portion 15, and the passageways 1 8 communicate with the channels 1 7 and hence with the grooves 16. The grooves 16 and passageways 1 8 have sealed ends.A solid portion 2a of the tubular member 2 extends from the vacuum chamber 3 and is operably connected to the piston rod 1 9 of a second piston/cylinder arrangement20.

The vacuum chamber 3 has an outlet 21 which is connected to suction means, not shown.

In use, a slurry comprising, for example, refractory fibres and a binding agent in aqueous suspension, is fed through the chamber 1 via the inlet 5 and the outlet 6. The piston/ cylinder arrangement 1 2 drives the sheath 8 via the piston rod 11 and the arm 10, with an oscillatory motion about the longitudinal axis of the sheath. This movement of the sheath causes the fingers 1 3 attached thereto to agitate the slurry within the chamber to resist the solids separating out from the slurry. The oscillatory motion also resists the sleeve 22 from adhering to the sheath 8 as described below.

The suction means connected to the outlet 21 draws a partial vacuum in the vacuum chamber 3, creating a pressure difference between the two chambers 1, 3. The liquid component of the slurry is drawn from the chamber 1, through the grooves 1 6 and channels 1 7 into the passageways 18. The solid component of the slurry is deposited on the tubular member 2 by filtration. The liquid is then drawn along the passageways 1 8 towards the vacuum chamber 3 where the liquid is drawn into the chamber via the channels 1 7 and the grooves 1 6. The liquid leaves the vacuum chamber 3 via the outlet 21.

The piston/cylinder arrangement 20 drives the tubular member 2 back and forth with a relatively slow forward stroke, (towards the left of the apparatus as shown in Fig. 1), and a relatively rapid return stroke. The slow for- ward stroke carries the deposited solids out of the slurry chamber 1 through the annular space 9 within the sheath 8. The grooves 1 6 guide the deposited solids out of the sheath in a rectilinear motion. The rapid return stroke of the tubular member 2 causes the deposited material to be dislodged from the member 2 at the start of the return stroke so that the member 2 leaves the deposited material behind. The deposited solids are therefore discharged from the apparatus in the form of a continuous sleeve.

The process may be initiated by using a suitably dimensioned dummy sleeve of a porous material. The dummy sleeve is inserted into the sheath and, when the apparatus is activated, the dummy sleeve is discharged from the sheath ahead of the formed sleeve.

Claims

1. A method of making a sleeve of material from a slurry of solids in a liquid carrier comprising feeding the slurry to an axially extending surface of a tubular member, drawing the liquid component of the slurry through perforations in the axially extending surface of the member to deposit the solids component of the slurry on that surface, cauing the member to reciprocate axially to resist adhesion of the deposited material to the member, moving the deposited material along the axially extending surface of the member and through a sheath and separating the formed sheet from the member and the sheath.

2. A method according to claim 1 in which the tubular member is caused to reciprocate with a motion which is faster in one direction than in the other direction.

3. A method according to either preceding claim in which the sheath is caused to oscillate along a rotary path about the axis of the tubular member.

4. A method of making a sleeve of material from a slurry of solids in a liquid carrier, substantially as described with reference to the accompanying drawings.

5. Apparatus, for making a sleeve of material from a slurry of solids in a liquid carrier, comprising a chamber for holding the slurry, the chamber having opposite sidewalls, a tubular member, having perforations in an axially extending surface thereof, extending across the chamber and, extending beyond one sidewall, a sheath located about a portion of the tubular member with a clearance in between, means for reciprocating the tubular member between the sidewalls and means for drawing a vacuum in the chamber, whereby when a vacuum is drawn in the chamber liquid egresses from the chamber via the tubular member and solids are-deposited thereon and reciprocation of the member urges the deposited solids out of the chamber via the clearnace between the member and the sheath.

6. Apparatus according to claim 5 in which the sheath is oscillatable along a rotary path about the axis of the tubular member.

7. Apparatus according to claim 6 in which fingers extend from the sheath into the chamber for agitation of the slurry.

8. Apparatus according to any of claims 5 to 7 in which the perforated axially extending surface of the tubular member has axially extending grooves therein.

9. Apparatus, for making a sleeve of material from a slurry of solids in a liquid carrier, substantially as described and with reference to the accompanying drawings.