US3174230A - Apparatus for the fluidising heat treatment of sheet material - Google Patents

Description

March 23, 1 H. H. GREEN ETAL APPARATUS FOR THE FLUIDISING HEAT TREATMENT OF SHEET MATERIAL Filed June 14,

United States Patent 3,174,230 APPARATUS MFR THE FLUIDESTNG BEAT TREAT- MENT 0F SHEET MATERHAL Harold Hurdley Green, Castle Broniwich, and Roy Reginald Lee, Edgbaston, Birmingham, England, assignors to Dunlap Rubber Company Limited, County of London, England, a British company Filed June 14, 1962, Ser. No. 202,579 Clmms priority, application Ereat Britain, June 27, 1961, 23,140/ 61 11 Claims. (Cl. 3495) This invention relates to apparatus for heat treatment of sheet materials and is an improvement in or modification of the invention described in the specification of Patent 3,061,943, Nov. 6, 1962.

In the specification of UK. Patent No. 885,513 apparatus is described for treating textile fabric by passing the fabric through a heated bed consisting of particles of sand or minute glass beads known as Ballotini, the bed being maintained in a fluidised or suspended state by a current of air passing through the bed.

In the specification of the above mentioned patent 3,061,943 a closure for the base of a fluidised bed container is described, said closure comprising a pair of rollers in peripheral contact adapted to permit the passage of sheet material therebetween, a casing extending longitudinally of the rollers and conforming to part of the peripheral portions thereof adjacent the fluidised bed container and means to prevent the egress of particles of the bed through the clearance between the casing and the peripheral portion of each of the rollers adjacent thereto. a

The present invention provides an improved means for preventing the escape of particles of the bed through the clearance between the casing and the peripheral portion of each of the present rollers adjacent thereto.

According to the invention, a closure for a fluidised bed container comprises a pair of parallel rollers rotatable in opposite directions and having a nip through which sheet material may be passed, a casing having a pair of parallel side members extending longitudinally of the rollers, each side member being adjacent to and shaped to conform closely to the peripheral surface of its respective roller, means being provided for directing a flow of gas on to each roller surface to prevent the escape of particles of the bed through clearances between the side members and their respective rollers, exhaust means being provided to allow said flow of gas to be withdrawn from the closure.

Preferably the flow of gas is directed substantially tangentially to each roller surface in a direction opposed to the direction of rotation of the roller, and deflectors are provided to confine the flow of gas to a tangential direction with respect to the rollers.

Preferably also, each side member is provided with a sealing member for engagement with its associated roller, the means for directing a flow of gas on to the roller surface being positioned betwen the nip and the sealing member in the region adjacent the fluidised bed container.

One embodiment of the invention will now be de scribed, by way of example, with reference to the accompanying drawing, which is a cross-sectional end elevation of the lower part of a fluidised bed container, the cross-section being taken in a vertical plane passing centrally through the container at right angles to the plane in which fabric is passed through the apparatus.

The fluidised bed container 1, which is of the form described in the specification of co-pending Patent No. 3,061,943, is provided at its base 2 with a closure 3 constructed as follows: A pair of freely rotatable, internally 3,174,239 Patented Mar. 23, 1965 ice water-cooled, rubber-covered rollers 4 and 5 are disposed with their axes horizontal and parallel to each other one on each side of and below a narrow vertical channel 6 in the base of the fluidised bed container 1 through which fabric 7 may be fed vertically upwards to the bed 8. The bed 8 consists of small solid particles kept in a state of turbulence by air forced into the base of the bed, through a first gas supplying means comprising metal gauze filters 9, 10 supported between perforated plates 9a, 9b and 10a, 1011, respectively, and pressurized galleries 11 and 12, the air issuing from these galleries, respectively, through the filters 9 and 10. The bed is heated by electric heater elements 13. The top of the container is an exhaust for the air from the first gas supplying means. The rollers 4 and 5 are supported adjacent to one another to form a nip 14 through which the fabric 7 may be fed upwardly into the bed 8 via the channel 6.

The upper surfaces of the rollers 4 and 5, Le. the surfaces which at a given moment are in the region adjacent to the container 1, are surrounded by a casing 15 which is attached to the base 2 of the fluid bed container and sealed thereto by rubber seals 16 and 17. The casing 15 comprises a pair of end plates (not shown) having sealing means (not shown) for preventing the escape of particles from the ends of the rollers, and a pair of hollow side members 18 and 19 extending longitudinally one on each side of and parallel to the pair of rollers 4.- and 5. The sealing means for the end plate is described in the specification of Patent 3,061,943. The two side members 18, 19 of the casing are similar to one another in all respects except that one is the mirror image of the other and one only will, therefore, be described.

The hollow side member 18 comprises a face 20 adjacent to the associated roller which, viewed in transverse cross-section has the form of a quadrant of a circle conforming closely to the surface of the roller 4, the clearance between the roller and the member being approximately half the average diameter of the fluidised bed particles. The side member is attached to the base 2 of the container by adjustable supporting means to enable the clearance to be adjusted.

The supporting means for the side member 18 comprises a pair of ring bolts 21, one at each end of the member, only one of the bolts being shown. Each ring bolt is adjustably secured at its upper end by nuts 22 and 23 to a bracket 24 fixed to the container 1 and pivotally secured at its lower end to a shackle pin 25 which is mounted in a pair of lugs 22%, only one of which is shown, formed on the side member 18. A pair of eccentrically mounted pivot pins 27, only one of which is shown, are also provided to support the side member 18, the pivot pins 27 being attached to rotatable shafts 28 mounted on the respective end plates and the pins 27 engaging corresponding sockets formed in the ends of the member 18. The axes of the pins 27 are parallel to, but spaced from the axes of the shafts 28, so that rotation of the shafts 28 moves the pins 27 and thus the side member 18 about the axis of the pins 25 radially towards or away from the roller 4. Adjustment of the clearance between the surface 20 of the member 18 and the surface of the roller 4 is obtained by the combined effect of altering the angular positions of the pivot pins 27, and transversely adjusting the position of the axis of the pins 25 by vertically moving the bolts 21 by means of the nuts 22 and 23.

The hollow side members 18, 19 are each provided with a second gas supplying means comprising an inlet passage 29 into which air may be supplied at a pressure of approximately ten pounds per square inch, a pressure gauge 30 being provided to measure the pressure of the air within each member. The second gas supplying means further comprises a slit 31 in the wall of each member in a position vertically above the axis of the associated roller, the slit running longitudinally and extending along substantially the whole length of the member, parallel with the axis of the roller, and communicating withthe hollow interior of the member to allow air to flow from the member to impinge on the upper pe- Iiphery of the associated roller. Air supplied to the hollow casing members may thus be forced through the slit 31 and be directed by the slits tangentially, as indicated by the arrows, to the upper surfaces of therollers in directions opposed to the direction of rotation of the respective rollers. The air passing through the slits has the effect of removing from the roller surfaces any fluidised bed particles which may have escaped downwardly through the narrow channel through which the material-is fed to the bed, and which may then have been carried upwardly on the roller surfaces.

In order to confine the air forced throughthe slit to the region immediately adjacent to the roller, thus providing a concentrated tangential air blast, each of the members 18, 19 is provided with a deflector- 32 forming an extension of the portion of the casing member vertically above the axis of the associated .roller and positioned close to the upper surface of the roller. A sealing member in the form of a longitudinally extending felt strip 33 is provided at the lower edge of eachside member, the strip 33 bearing against the surface of the associated roller so. that a pressure slightly higher than that in the fluidised bed 8 may be built up in the space between the rollers and the base of the fluidised bed container, this effect further helping to prevent the escape of particles from the bed.

Exhaust means is provided to carry away the air supplied through the slits 31. The exhaust means takes the form of a number of pipes 34 communicating via galleries 35 with the space above the roller and leading out to atmosphere, the pipes 34 being turned downwardly to direct any particles which are suspended in the air passing through the exhaust means into a trough (not shown) beneath the apparatus. A duct (not shown) is provided to connect the trough to the upper part of the interior of the container, and a supply of air' under pressure is directed into the duct to carry the particles from the trough to the container.

A pair of baflles 36 is secured to the base 2 of the container, the baflles extending alongside their associated rollers along. the whole length of the rollers. Each baffle has a ridge 37 directed towards the associated slit 31 to intercept the stream of air emerging from the slit and thus to direct the larger part of the air stream upwardly into the associated gallery 35. A small flow of air is directed downwardly by the baflles 37 towards the nip i4 and then upwardsthrough the channel 6 into the bed 8, but this flow is impeded by the narrow passages formed between the tips 38 of the baffles 37 and the rollers, and is arranged to be only just sufficient to prevent a large downward flow of particles from the bed through the channel 6.

The provision of separate exhaust means for the air passing through the slits 31 has the advantage that apart from removing the escaped particles, the major portion of this. air is not forced into the fluidised bed, and thus does not affect the degree of fluidisation thereof.

Having now described our invention, what we claim is:

1. A fluidisable bed comprising a container for fluidisable material, a base attached to the container, said base having a first gas supplying means for supplying pressurised gas to .the container, the. container having an exhaust from the first gas supplying means, a closure attached to the base and comprising a pair of parallel rollers rotatable in opposite directions and forming the nip through which sheet material may be passed, a pair of side members extending longitudinally of the rollers, each side member being adjacent and shaped to conform closely to the peripheral surface of its respective roller, and a second gas supplying means associated with the side members for directing the flow of gas onto each roller surface to prevent the escape of particles of fluidisable material of the bed through clearances between the side members and their respective rollers, and exhaust means separate from the exhaust of the first gas supplying means, said exhaust means having an exhaust passageway leading to the clearances between the side members and their respective rollers, and disposed between the rollers and the container for exhausting and for collecting gas solely from the second gas supplying means.

2. A fluidisable bed according to claim 1 wherein the means for directing a how of gas onto the rollers is positioned to direct said flow substantially tangentially to each roller surface in a direction opposed to the direction of rotation of the roller. 3. A fluidisable bed according to claim 1 wherein each side member is provided with a sealing member for engagement with its associated roller, the means for directing a flow of gas on to the roller surface being positioned between the nip and the sealing member in the region adjacent the fluidised bed container.

4. A fluidisable bed according to claim 1 wherein the means for directing a flow of gas on to each roller surface is formed integrally with the side members, each side member comprising a passage for connection to a supply of gas under pressure and communicating with a slit formed in a wall of the member adjacent to the associated roller, said slit extending along substantially the Whole length of the roller.

5. A fluidisable bed according to claim 1 wherein the means for directing the flow of gas on to each roller surface is disposed so as to direct said flow across the surface of the associated roller in the region adjacent the fluidised bed container, and comprising a baflle for each roller to restrict the flow of gas towards the nip between the rollers.

6. A fluidisable bed according to claim 1 wherein means is provided for each side member for adjusting the clearance between the side member and its associated roller.

7. .A fluidisable bed according to claim 6 wherein the means for adjusting the clearance between each side member and its associated roller comprises means for rotatably supporting the side member about a transversely adjustable pivotal axis parallel to the axis of the associated roller, and means for turning the side memher about said pivotal axis whereby the side member may be moved radially towards or away from the associated roller.

8. A closure for a fluidized bed container having a channel for the passage of material upwardly into the fluidized bed container which comprises a pair of rollers below said container and having a nip below and aligned with said channel, a pair of baffles extending downwardly from said channel to close proximity to said nip and spaced to form a, passage for said material from said nip to said channel, a pair of side members below said container one on each side of said pair of rollers and having a surface closely spaced from the surface of an adjacent roller and terminating at a distance from said baffles and having a slit to direct a jet of air against the surface of said adjacent roller in a direction opposite to the direction of rotation of said roller, and means for Withdrawing air from the space between said side members and said baffies.

9. The closure of claim 8 in which said slit is positioned to direct said air jet tangentially relative to the surface of said adjacent roller.

10. The closure of claim 9 in which said surfaces. of

5 6 said side members adjacent said rollers is arcuate and References Cited by the Examiner complementary to the adjacent surface of a roller. U IT D TAT PA NT 11. The closure of claim 8 in which said surface ad- N E S ES TE S jacent said roller is spaced a distance from the surface 2873597 2/59 Fahnnger 34-242 of the adjacent roller equal to approximately half the 5 35691943 11/62 Bennett 34-242 average diameter of the particles of the fluidized bed. NORMAN YUDKOFF, Primary E aminer,

Claims (1)

1. A FLUIDISABLE BED COMPRISING A CONTAINER FOR FLUIDISABLE MATERIAL, A BASE ATTACHED TO THE CONTAINER, SAID BASE HAVING A FIRST GAS SUPPLYING MEANS FOR SUPPLYING PRESSURISED GAS TO THE CONTAINER, THE CONTAINER HAVING AN EXHAUST FROM THE FIRST GAS SUPPLYING MEANS A CLOSURE ATTACHED TO THE BASE AND COMPRISING A PAIR OF PARALLEL ROLLERS ROTATABLE IN OPPOSITE DIRECTIONS AND FORMING THE NIP THROUGH WHICH SHEET MATERIAL MAY BE PASSED, A PAIR OF SIDE MEMBERS EXTENDING LONGITUDINALLY OF THE ROLLERS, EACH SIDE MEMBER BEING ADJACENT AND SHAPED TO CONFORM CLOSELY TO THE PERIPHERAL SURFACE OF ITS RESPECTIVE ROLLER, AND A SECOND GAS SUPPLYING MEANS ASSOCIATED WITH THE

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