GB2095218A

GB2095218A - Vessel for handling particulate materials

Info

Publication number: GB2095218A
Application number: GB8200990A
Authority: GB
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1981-02-06
Filing date: 1982-01-14
Publication date: 1982-09-29
Also published as: ES8401666A1; ES509339A0; SE8200678L; KR830008913A; JPS57153884A; IT1195914B; BE892038A; FR2499526A1; IT8219365A0; GB2095218B; DE3203629A1

Abstract

An enclosed vessel for handling particulate materials is provided with an internal lining comprising a pair of superimposed pliable sheets 36, 36' joined together around their edges, whereby on the internal pressure of the vessel being changed, movement of the innermost sheet 36 causes the release of any material which has been adhering to the vessel. <IMAGE>

Description

SPECIFICATION Vessel for handling particulate materials The handling of bulk particulate materials, such as their storing, feeding or processing, frequently entails difficulties because of the adhering propensities of many types or compositions of powders and small granules. Adherence of particulate materials to surfaces about and within storage and process equipment, and in turn the accumulation of the adhering material can in some instances constitute an especially detrimental and hazardous occurrence. For instance, when handling fissionable compositions such as in the processing of fuel for nuclear reactors, an accumulation thereof within equipment can exceed safety requirements with respect to the materials' critical mass.Moreover, many more commonplace materials in fine particulate form are highly combustible and therefore should not be permitted to adhere and amass within equipment and thereby cause a fire or explosion potential.

A number of means have been suggested for dealing with this problem of handling adhering particulate materials as is evident from the detailed disclosure of U.S. Letters Patent No.

4,081,1 1 0. Typicai remedies proposed in the art include the installation in a storage or processing vessel of one or more expandable bladder-like bags or a flexible skirt-like liner that can be inflated or flapped by the application of a fluid into the interior or underside thereof. Such remedial systems require connections for the disengaging means or device with a source of an activating fluid, and also some control means for the application of the fluid thereto.

This invention relates to vessels for the storage, supplying, processing and the like handling operations of particulate materials. The invention comprises such a vessel having an effective and economical means for overcoming the adherence and in turn accumulation of particulate material on the inner retaining surfaces thereof.

The vessels of this invention are closed to the atmosphere, and include means associated therewith for producing changes in the pressure within the interior of the closed vessel. The invention comprises a uniquely constructed lining deployed to cover the portions of the inside retaining surface of a containing vessel that are likely to come into contact with the particulate material contained therein and which are prone to retaining thereon the particulate material.

The vessel lining is provided by one or a plurality of assembled units with each constructed of a pair of superimposed pliable sheets joined together about their. common peripheral edge. The means for joining the sheets' periphery should provide a substantially fluid impermeable seal thereabout.

This invention is especially useful and effective in fluidized bed blending apparatus for mixing particulate fissionable materials for nuclear reactor fuel such as disclosed in U.S. Letters Patent Nos. 4,168,914 and 4,172,667.

This invention attempts to provide an improved vessel for the more effective handling of particulate materials having a propensity for adhering to the retaining surface of containers.

This invention also attempts to provide a vessel for the handling of adhering particulate materials comprising a self-actuating lining member therein that does not require or include any fluid conduits or control means connected therewith to perform its function of disengaging particualte material adhering thereto.

This invention additionally attempts to provide a means for overcoming the adherence of particulate materials in vessels that is readily adaptable for installation in existing equipment as well as that which is newly manufactured, is economical in material, installation and operating costs, and can be formed or assembled from commercially available components.

This invention attempts to provide a vessel for the handling of adhering particulate materials having effective means for freeing the inside retaining surfaces thereof from adhering material that do not require or govern its performance.

This invention attempts to provide a vessel for the safe handling, including blending, of adhering particulate materials including fissionable components wherein safety factors necessitate the prevention of accumulating quantities of adhering fissionable components approaching their critical mass.

According to the present invention, there is provided an enclosed vessel for handling particulate materials having a propensity for adhering to the retaining surfaces of containers, comprising a vessel closed to the atmosphere provided with means for changing the internal pressure therein, said vessel having a substantial portion of its inside surface covered with a lining constructed of a pair of superimposed pliable sheets joined together at a relatively narrow marginal portion around their common periphery and with an intermediate unjoined area located within the perimeter of the joined marginal portions thereof.

The present invention will be further described, by way of example only, with reference to the accompanying drawing, in which: Figure 1 is an elevated view, partly in crosssection with parts broken away, of a closed vessel with a lining constructed according to this invention; and Figure 2 is a perspective view of a lining component for use in this invention.

Referrring to Figure 1 of the drawing, the vessel 10 of this invention comprises a container 1 2 closed to the atmosphere, and provided with suitable means for the intake and discharge of particulate materials. The intake means can consist simply of a connecting conduit 1 4 provided with a valve 1 6 which communicates with the interior 1 8 of the vessel 1 0. The vessel discharge means can consist of an outlet conduit 20, provided with a valve 22, communicating with the interior 1 8 of vessel 10.

Conveyance of particulate material for entering or exiting the vessel 10 through said intake and discharge conduit means can be induced or assisted by the application of propelling fluid pressure conditions of increased or decreased levels within the interior 1 8 of vessel 10. Internal pressure conditions, or changes therein, within vessel 10 for any purpose or need, including filling or emptying the vessel, can be effected by means described hereinafter.

The vessel 10 in this invention can comprise a container 12 for service in any of a variety of particulate material handling systems, including, for example, a silo for the storage of bulk particulate material, a stock supply hopper for the dispensing of particulate feed stocks, or a chamber in a processing apparatus such as a powder blending device with fluidized bed agitating means therein. The apparatus of the aforementioned U.S. Patent Nos. 4,168,914 and 4,172,667 constitute examples of the latter.

Being closed to the ambient atmosphere, the pressure conditions within the interior 1 8 of vessel 10 can be easily and substantially changed, and even rapidly fluctuated. The internal pressure of the vessel 10 for instance, can be increased to a superatmospheric condition or reduced to a subatmospheric condition by means of a connection, such as pipe 24 having a valve 26 therein, of the interior 1 8 of the vessel with an external source of increased or decreased fluid pressure. A source of superatmospheric pressure comprises a compressor (not shown) or supply of a gas under pressure (not shown), and a source of subatmospheric pressure comprises a vacuum pump (not shown).Moreover, pressure changes in the interior 18 of vessel 10, or fluctuations therein, entirely within either the superatmospheric range or subatmospheric range with respect to external ambient conditions, can be produced by manipulating the flow rate of a pressure governing gas supplied from a source of either increased or reduced pressure.

When the closed vessel 10 comprises a fluidizing bed blending unit or system 28 of a preferred embodiment of this invention, and as shown in the aforementioned U.S. Patent Nos.

4,168,914 and 4,172,667, the internal pressure of the vessel 1 0 can be changed by manipulating the pressure of the supply of fluidizing gas in the blending operation. The control of the vessel pressure through the fluidizing gas supply is evident in the disclosures of the aforesaid patents, wherein the routine operating procedure and sequence for effecting the particle blending process results in pressure variations within the system. A fluidizing gas system is illustrated as a supply pipe 30 provided with a valve 32 connecting the fluidizing means 28 with a source of fluidizing gas (not shown).

Referring to Figure 2 of the drawing, the lining member 34 for the vessel 10 of this invention is composed of a pair of superimposed pliable and deformable sheets 36-36', joined together at a relatively narrow marginal portion 38 thereof around their common periphery. The joined marginal portion 38 constitutes a relatively minor area of the total expanse of the sheets.

Intermediate of the joined margin around their common periphery, the pair of sheets are not attached to one another in at least one major area thereof whereby either pliable sheet of the superimposed pair can move free of the other sheet.

The pliable sheets 36-36' can be joined to each other about their common periphery 38, and in any other appropriate locations if need be, with suitable bonding adhesives. Other effective uniting means can be used as alternatives, including any measure that provides a substantially fluid impervious seal between the two sheets in order to provide a closed section therebetween isolated from external ambient atmospheric conditions.

Alternate measures include tight stitching, rivettype fasteners, and welding or thermal fusion with thermoplastic sheets.

Depending upon size and weight factors of the adjoining pair of pliable sheets, the two sheets of the pair can be affixed to one another at one or more additional locations 40 interspersed intermediate of their joined periphery 38.

Additional attaching of the superimposed sheets may be desirable to import greater integrity and durability to the composite unit 34 thereof. The same or different means can be used to join such additional intermediate locations as are used in the peripheral bonding, for example the marginal portions of the sheets about their periphery can be joined together with an adhesive whereas widely spaced stitching 42-42' with thread can be used intermediate the joined marginal portion about the periphery 38 as shown in Figure 2.

The two pliable and deformable sheets 36-36' comprising the superimposed pair preferably and most conveniently are of substantially the same general area dimensions and coextensive. Thus they can be matched and conterminously superimposed one on the other and affixed together by joining a narrow marginal portion of each around their common periphery.

However, pliable sheets of unlike sizes or shapes can be employed with somewhat reduced convenience and efficiency in fabrication. For instance, one sheet of the pair can be made up of a composite of several individual pieces which are fractional portions of the total area of the other sheet. However, it is necessary to join the entire peripheral edge of each of such fractionally sized portion or piece to the other adjoining larger sheet in order to close off and seal around the borders of the fractional portions so as to provide an independent enclosed section therebetween.

Pliable sheets for the fabrication of linings for this invention can be composed of any substantially fluid impermeable and flexible composition that is appropriately compatible and enduring with the particulate material with which the lined vessel is to be used. Potential compositions include natural or synthetic elastomers such as rubber or neoprene, organic polymers such as polyolefins, and related materials that can be formed into flexible, substantially fluid impermeable films or sheets.

Textile sheets of a sufficiently tight weave, or impregnated so as to possess some fluid impermeability can also be used.

Suitable lining members for use in the vessel 10 of this invention comprise some commercially available aircraft deicer devices, such as marketed by B.F. Goodrich Co.

One, or an assembled plurality of the above described lining units 34 composed of the superimposed and joined pair of pliable sheets 36-36', are secured over all or selected portions of the inside retaining surface 44 of the vessel 10.

The lining 34, or assembled units therefor, are deployed over the surface 44 so as to cover essentially all portions thereof which routinely come into contact with the particulate material and are also prone to significant retention or crustation of the particulate material thereon. For example as shown in the drawing, the lining 34 can be applied to substantially cover the side surface 44 or the generally vertical walls of vessel 10, and also the converging bottom wall surfaces.

An adhesive or other suitable means can be used to affix the lining 34 to the inside retaining surface 44 of the vessel 10 by bonding to the vessel 10 the one pliable sheet 36' of the pair immediately adjoining the vessel's inside surface. Thus, the other or opposite pliable sheet 36 spaced from the vessel surface 44 is capable of movement, such as flexing, over a major unjoined portion and area thereof free of restraint from the other pliable sheet 36' that adjoins and is bound to the vessel surface 44. This movable portion of the sheet 36 opposite to the vessel's inner surface, constitutes the inner retaining surface that is exposed to the vessel contents.

In use, pressure changes or variations occur within the closed vessel 10, attributable to the routine operation of gas actuated fluidized bed blending as disclosed in the aforesaid patents, or even due to the use of pressure differences to transfer particulate material into or out from the vessel 10. Such operational changes or variations in internal; pressure are generally adequate to induce sufficient movement of the exposed inner pliable sheet 36 to cause any adhering built up particulate material, or crustations thereof, on the exposed inner lining 34 face to break loose and fall away with each cycle of operation. Thus, the inside retaining surfaces 44 of the vessel 10 can be maintained substantially free from building up deleterious accumulations or crustations of hungup particulate material thereon without additional apparatus or controls.

In those systems wherein the inherent operational pressure changes within the closed vessel 10 are not sufficient to produce adequate movement of the exposed inner pliable sheet to disengage the particulate material, or in those devoid of any pressure changing operations, the necessary disengaging movement of the inner pliable sheet can be achieved by means of a simple direct connection of the vessel's interior 1 8 with a source of either superatmospheric pressure, e.g., compressor, or subatmospheric pressure, e.g, vacuum pump, through a pipe such as 24.

Claims

1. An enclosed vessel for handling particulate materials having a propensity for adhering to the retaining surfaces of containers, comprising a vessel closed to the atmosphere provided with means for changing the internal pressure therein, said vessel having a substantial portion of its inside surface covered with a lining constructed of a pair of superimposed pliable sheets joined together at a relatively narrow marginal portion around their common periphery and with an intermediate unjoined area located within the perimeter of the joined marginal portions thereof.

2. A vessel as claimed in claim 1, wherein the sheet of the pair of pliable sheets forming the covering lining that adjoins the inside surface of the vessel is bonded to said inside vessel surface.

3. A vessel as claimed in claim 1 or claim 2, wherein the means for changing the internal pressure of the vessel closed to the atmosphere comprises a connection to a source of gas under pressure communicating with the interior of said vessel.

4. A vessel as claimed in any one of the preceding claims wherein the vessel closed to the atmosphere contains fluidized bed blending means.

5. An enclosed vessel for handling particulate materials having a propensity for adhering to the retaining surfaces of container, comprising a vessel closed to the atmosphere provided with means for changing the internal pressure therein, said vessel having a substantial portion of its inside surface covered with a lining composed of at least one lining unit constructed of a pair of superimposed pliable sheets joined together at a relatively narrow marginal portion around their common periphery and with an intermediate unjoined area located with the perimeter of the joined marginal portions thereof, thereby enabling portions of one of said pliable sheets to undergo movement free of the other sheet.

6. A vessel as claimed in claim 5, wherein the sheet of the pair of pliable sheets forming the covering lining that adjoins the inside surface of the vessel is adhesively bonded to said inside vessel surface.

7. A vessel as claimed in claim 5 or claim 6, wherein the means for changing the internal pressure of the vessel closed to the atmosphere comprises a connection to a source of gas under a pressure different from that of ambient conditions communicating with the interior of said vessel.

8. A vessel as claimed in any one of claims 5 to 7, wherein the vessel closed to the atmosphere contains fluidized bed blending means.

9. A vessel as claimed in any one of claims 5 to 8, wherein the vessel lining of a pair of superimposed pliable sheets comprises a deicer device for aircraft.

10. An enclosed vessel for handling particulate material having a propensity for adhering to the retaining surfaces of containers, comprising a vessel closed to the atmosphere having intake and discharge means and provided with means for changing the internal pressure therein comprising a connection to a source of gas under a pressure different from that of ambient conditions communicating with the interior of the vessel, said vessel having a substantial portion of its inside covered with a lining composed of at least one lining unit constructed of a pair of superimposed pliable sheets joined together at a relatively narrow marginal portion around their common periphery and with at least one intermediate nonjoined area located within the perimeter of the joined marginal portions thereof, thereby enabling portions of one of said pliable sheets to undergo movement free of the other sheet.

11. A vessel as claimed in claim 10, wherein the vessel lining of a pair of superimposed pliable sheets comprises a deicer device for aircraft.

12. A vessel as claimed in claim 10, wherein the means for changing the internal pressure of the vessel closed to the atmosphere comprise a connection to a source of gas under subatmospheric pressure communicating with the interior of said vessel.

13. A vessel as claimed in claim 10, wherein the means for changing the internal pressure of the vessel closed to the atmosphere comprises a connection to a source of gas under superatmospheric pressure communication with the interior and said vessel.

14. An enclosed vessel for handling and blending particulate material having a propensity for adhering to the retaining surfaces of containers, comprising a vessel closed to the atmosphere containing fluidized bed blending means and provided with means for changing the internal pressure therein comprising a connection to a source of gas under pressure communicating with the interior of the vessel, said vessel having a substantial portion of its inside surface covered with a lining composed of at least one lining unit constructed of a pair of superimposed continuous pliable sheets joined together at a relatively narrow marginal portion around their common periphery and with at least one intermediate unjoined area located within the perimeter of the joined marginal portions thereof, thereby enabling portions of one of said pliable sheets to undergo movement free of the other sheet in response to changes in pressure within the closed vessel.

1 5. A vessel as claimed in claim 14, wherein the sheet of the pair of pliable sheets forming the covering lining that adjoins the inside surface of the vessel is adhesively bonded to said inside vessel surface.

16. A vessel as claimed in claim 14 or claim 1 5, wherein the pliable sheet of the pair of superimposed pliable sheets comprise a deicer device for aircraft.

17. A vessel as claimed in any one of claims 14 to 16, wherein the vessel lining of a pair of superimposed pliable sheets are adjoined together at limited portions in areas intermediate to the joined relatively narrow margins thereof.

18. A vessel as claimed in any one of claims 14 to 17, wherein the means for changing the internal pressure of the vessel closed to the atmosphere comprises a connection to a source of gas undersuperatmospheric pressure and a connection to a source of gas under subatmospheric pressure each communicating with the interior of said vessel.

1 9. A vessel as claimed in any one of claims 14 to 18, wherein the fluidized bed blending means is connected with a source of gas under pressure to fluidize and blend particulata material within the closed vessel.

20. A vessel as claimed in claim 1, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.