GB1597781A - Handling of flowable material - Google Patents

Description

(54) IMPROVEMENTS IN AND RELATING TO THE HANDLING OF FLOWABLE MATERIAL (71) We, TRYTHALL DESIGN AND DEVELOPMENT LIMITED, a British Com- pany, of East Hill, Morpeth, Northumberland NE61 2AA, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a valve assembly and to a hopper fitted therewith.

According to the invention there is provided a valve for handling powders, granules and like flowable material, comprising a body having an inlet for the material at one end and an outlet tube for the material at the other end, a member positioned within the inlet to define therewith an annular material aperture and having a valve seat in its inner surface, a piston member within the body sealingly slidable between an extended position in which the piston member engages the valve seat in pressure-tight manner to close the aperture and a retracted position in which the aperture is open and is connected with the outlet tube via a passage formed in the piston, actuating and control means for effecting movement of the piston between its extended and retracted positions, and means operable when the piston is in the extended position to direct fluid under pressure into the space within the body and adjacent portion of the outlet tube closed off by the piston and so transport material from that space away through the outlet tube.

In another aspect the invention provides a hopper or tank tor powders, granules and the like flowable material havmg a bottom discharge outlet the flow through which is controlled by means of a valve assembly as aforesaid.

Other preferred aspects of the invention will be found in the detailed description set out below and in the appended claims to which attention is hereby directed.

When conventional pneumatic handling units are installed below a granular material hopper there is often a length of trunking such as an isolating slide of some kind, followed by a material control valve of restricted size. Conventional fluidising devices may be ineffective to fluidise the material within this trunking and may even aggravate the problem. If the fluidising device is operated when the inlet from the hopper is closed, the effect on the material within the trunking may be merely to pack it more tightly rather than to remove the blockage. The new valve provides a means whereby this difficulty can be overcome and the granular material may be fluidised in the trunking or pipework between the hopper and a main pneumatic conveyor pipe. The apparatus has the further advantages that it is of simple construction and is easy to manufacture.

An embodiment of the invention will now be described with reference to the accompanying drawing which is a view in partial longitudinal section of a flow control and pneumatic handling assembly.

Referring to the drawing, a valve body for bolting to a hopper (not shown) containing powder or granular materials comprises a radial flange 20 for bolting to a corresponding flange on the underside of the hopper, a downwardly convergent frustoconical mouth portion 21, a cylinder portion 23 and a lower radial flange 24. A blower body generally indicated as 25 comprises an upper flange 26 bolted to the lower radial flange 24 on the valve body, a cylinder portion 27 and a lower radial flange 28. An outlet tube 29 has a radial flange 30 bolted to the lower flange 28 of the valve body and is formed with a right angle bend to direct powder or granular material horizontally from the assembly into a generally horizontal length of pneumatic trunking.

A conical member 30A having a smooth downwardly sloping top surface is mounted coaxially on flexible mounting bushes 10 within the mouth portion 21 of the valve body in spaced relationship thereto so that its periphery defines with the inner wall of the mouth portion an annular aperture 31 through which material may pass from the hopper into the cylinder portion 23. The member 30A is provided with a vibrator consisting of a ball 32 rotatable in a race 33 on supply of air or other appropriate fluid under pressure thereto via an inlet connector 34 mounted within a bush 10 and fluid supply conduit 35. An outlet conduit (not shown) connects the interior of the race 33 with the exterior of the assembly to allow escape of the pressurised fluid from the race.

An axially slidable tubular piston 1 mounted within the cylinder portion 23 of the valve body extends at its lower end into the cylinder portion 27 of the blower body and (in the position shown in the solid lines) into the outlet tube 29. The outer sidewall of the piston 1 is formed with closely spaced upper and lower radial flanges 2 between which is sandwiched a seal 36.An enlarged inner side wall portion 37 of the cylinder portion 23 provides a space within which the flanges 2 can move and which allows the piston to travel between a retracted position (shown by the solid lines) in which the annular space 31 is open to admit the powder or granular material through the interior of piston 1 to the outlet tube 29 to an extended position (shown by the dotted lines) in which the top end 37 engages an annular valve seat 38 formed in the lower surface of the conical member 30A said valve seat having a rubber seal therein. The seal 36 is in fluid tight engagement with the inner side wall portion 37. The lower end of the space within which the flanges 2 move is defined by a seal 3 at the top end of the blower body 25 which slidably engages in fluid-tight manner the outer sidewall of the piston 1. The upper end of said space is similarly defined by a seal 3A.A first actuating fluid port 39 communicates via a radial passage 40 with an annular space above the flanges 2 and a second actuating fluid port 40A communicates via a downwardly directed passage 41 and a radial passage 42 with the annular space below the flanges 2. Supply of fluid under pressure to the second port 40A as indicated by the arrows causes the piston 1 to move from the retracted position to the extended position, and the piston 1 may be caused to move in the opposite direction by supply of fluid to the first port 39. Dual purpose outer pressure and wiper seals SA and 6 engage the outer cylindrical surfaces of piston 1 to prevent fines from entering the annular piston space within the inner side wall portion 37 or a blower space (described below).

The inner side wall of the cylinder portion 27 of the blower body is also enlarged at an intermediate axial position to define with the outer sidewall of the piston 1 an annular chamber 5. A fluidiser inlet 43 communicates via a radial passage 44 with the annular chamber 5. The lower end of the piston 1 is formed with a plurality of radial holes 8 opening to its outer cylindrical surface, each communicating at its inner end with a respective axial hole 9 opening to the lower end surface of the piston. When the piston is in its extended position the holes 8 communicate with the annular chamber 5 to admit fluidising air via the axial holes 9 into the outlet tube 29.The annular chamber 5 is sealed to the piston 1 at its upper end by pressure seal 3 (which prevents blowing air from passing into the annular space immediately above within which the flanges 2 are movable or reciprocate) and at its lower end by dual purpose pressure and wiper seal 4.

In order to effect entry of the powder or granular material from the hopper through the aperture 31 and to transport the material from the outlet tube 29, pneumatic control means (not shown) are provided at a suitable location in, on or adjacent to the assembly. The control means is operable to control in the correct sequence the operation and period of operation of supply of pressurised fluid through the connector 34 to the vibrator, the operation and period of operation of supply of pressurised fluid to the fluidiser inlet 43 to the fluidiser chamber 5, and the supply of pressurised fluid to an appropriate one of inlets 39 and 40A to effect movement of the piston 1 from its retracted position and its extended position and vice versa. The control means may be manual or it may be automatically operated.

In operation control means is arranged or is manually operated so as to cause the assembly to perform cyclically the following operations: (a) when the piston 1 is in its retracted position, pressurised fluid is supplied through connector 34 to the vibrator to agitate the powder or granular material and assist its flow through the opening 31 down the interior of the piston 1 to the outlet tube 29; (b) pressurised fluid is supplied to the inlet 40A to cause the piston 1 to move from its retracted to its extended position, and the supply of air to the vibrator is cut off during movement of the piston towards its extended position.When fully extended the top portion 37 of the piston engages the rubber gasket in the valve seat 38 to close the outlet 31 and to define with the lower surface of the conical member 30 a space within which the powder or granular material is entrapped and whose sole outlet is via the outlet tube 29. Tight sealing engagement between the piston and the valve seat is ensured by application of suffi- cient force to the piston during a final portion of its travel that the rubber valve seat gasket is appreciably flexed and that the rubber bushes 10 are flexed to allow slight upward movement of the member 30A; (c) during movement of the piston 1 to its extended position, pressurised fluid is admitted via inlet 43 to the chamber 5. As the tubes 8 pass into communication with the chamber 5, streams of air pass down the tubes 9 into the powder or granular material which fluidise said material and sweep it round the outlet pipe bend and away; and (d) fluid is supplied to the inlet 39 to return the piston 1 to the retracted position. During the early part of the piston movement the tubes 8 move downwards out of communication with the chamber 5 which shuts off the flow of fluid therefrom and during the downward movement the supply of fluid to the inlet 43 is also shut off.

Air supplied to the annular blower chamber 5 may be derived direct from a main air supply line (not shown) which will normally be provided with a pressure regulator, air dryer and filter. Air supplied to inlet 39 or 40A to effect movement of the piston between its extended and retracted positions is normally tapped off from the main air supply line through a fllter/ lubricator. A check valve or small receiver is normally provided upstream of the inlet 40A so that when the piston 1 is in its extended position and blowing is taking place, there is not an unacceptable loss of upward pressure holding the piston in the required pressuretight sealing engagement with the underside of member 30A. The line to inlet 40A is maintained at air mains pressure and needs no pressure regulation.The basic control for the apparatus comprises a four-way air valve (not shown) connected to the inlets 39 and 40A, together with an on-off air valve connected to the inlet 34 to supply air to the vibrator when the annular aperture 31 is open and to cut the air supply off when said aperture begins to close. The four way air valve may be operated by a solenoid (not shown) and controlled by timers settable to the desired filling and blowing times. The on-off control may then be by means of a single pole switch which may be a level controller in a distant receiving hopper or bin.

Various alterations may be made to the embodiment described herein without departing from the invention as defined in the appended claims. For example, instead of a pneumatic rotary ball and race vibrator there may be fitted an electrically driven vibrator.

Instead of the closed fluidising air chamber 5 from which fluid is supplied via the lower end of the piston, there may be provided an annular chamber having a narrow downwardly facing slot through which fluid may be injected into the powder or granular material.

WHAT WE CLAIM IS:- 1. A valve for handling powders, granules and like flowable material, comprising a body having an inlet for the material at one end and an outlet tube for the material at the other end, a member positioned within the inlet to define therewith an annular material aperture and having a valve seat in its inner surface, a piston member within the body sealingly slidable between an extended position in which the piston member engages the valve seat in pressure-tight manner to close the aperture and a retracted position in which the aperture is open and is connected with the outlet tube via a passage formed in the piston, actuating and control means for effecting movement of the piston between its extended and retracted positions, and means operable when the piston is in the extended position to direct fluid under pressure into the space within the body and adjacent portion of the outlet tube closed off by the piston and so transport material from that space away through the outlet tube.

2. Apparatus according to Claim 1, wherein the member positioned within the inlet is a vibratory member operable to transmit vibratory forces to material entering the material aperture to assist the passage of the material therethrough.

3. Apparatus according to Claim 2, wherein the vibratory member is supported in spaced relationship to the body to define the material aperture and is mounted on a plurality of flexible mountings.

4. Apparatus according to Claims 2 or 3, wherein the vibratory member is vibrated by a pneumatically operated device including a vibrating element impelled to move relative to the vibratory member by air under pressure.

5. Apparatus according to any preceding claim, wherein the piston is tubular, first portions of the inner sidewall of the body define with the external sidewall surface of the piston a fluid-tight annular cavity, radial flange members on the external surface of the piston are in slidable fluid-tight engagement with the inner sidewall, and fluid supply conduits communicate with the cavity on opposite sides of said flange members so that supply of fluid under pressure to a respective one of said conduits can cause movement of the piston in a required direction between its extended and retracted positions.

6. Apparatus according to Claim 5, wherein second portions of the inner sidewall of the body define with the external sidewall surface of the piston a second annular cavity provided with a channel through which pressurised fluid can be supplied thereto, and bores with the lower portion of the piston are positioned and arranged to communicate the second annular cavity with the space within the body and adjacent portion of the outlet tube when the piston is in the fully extended position.

7. Apparatus according to Claim 6, wherein the bores in the lower portion of the piston are positioned axially to communicate with the second annular cavity only after the piston has passed a final portion of its travel towards the fully extended position in which the head of the piston has produced appreciable deformation of a resilient valve seat gasket and/or appreciable deflection of flexible mountings for the inlet member has taken place.

8. Apparatus according to any preceding claim, wherein the outlet tube is formed with an elbow or right-angled bend.

9. A valve assembly for handling powders, granules and the like flowable materials, sub stantially as hereinbefore described with refer ence to and as illustrated in the accompanying drawing.

10. A hopper or tank for powders, granules

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. the chamber 5 which shuts off the flow of fluid therefrom and during the downward movement the supply of fluid to the inlet 43 is also shut off. Air supplied to the annular blower chamber 5 may be derived direct from a main air supply line (not shown) which will normally be provided with a pressure regulator, air dryer and filter. Air supplied to inlet 39 or 40A to effect movement of the piston between its extended and retracted positions is normally tapped off from the main air supply line through a fllter/ lubricator. A check valve or small receiver is normally provided upstream of the inlet 40A so that when the piston 1 is in its extended position and blowing is taking place, there is not an unacceptable loss of upward pressure holding the piston in the required pressuretight sealing engagement with the underside of member 30A. The line to inlet 40A is maintained at air mains pressure and needs no pressure regulation.The basic control for the apparatus comprises a four-way air valve (not shown) connected to the inlets 39 and 40A, together with an on-off air valve connected to the inlet 34 to supply air to the vibrator when the annular aperture 31 is open and to cut the air supply off when said aperture begins to close. The four way air valve may be operated by a solenoid (not shown) and controlled by timers settable to the desired filling and blowing times. The on-off control may then be by means of a single pole switch which may be a level controller in a distant receiving hopper or bin. Various alterations may be made to the embodiment described herein without departing from the invention as defined in the appended claims. For example, instead of a pneumatic rotary ball and race vibrator there may be fitted an electrically driven vibrator. Instead of the closed fluidising air chamber 5 from which fluid is supplied via the lower end of the piston, there may be provided an annular chamber having a narrow downwardly facing slot through which fluid may be injected into the powder or granular material. WHAT WE CLAIM IS:-

1. A valve for handling powders, granules and like flowable material, comprising a body having an inlet for the material at one end and an outlet tube for the material at the other end, a member positioned within the inlet to define therewith an annular material aperture and having a valve seat in its inner surface, a piston member within the body sealingly slidable between an extended position in which the piston member engages the valve seat in pressure-tight manner to close the aperture and a retracted position in which the aperture is open and is connected with the outlet tube via a passage formed in the piston, actuating and control means for effecting movement of the piston between its extended and retracted positions, and means operable when the piston is in the extended position to direct fluid under pressure into the space within the body and adjacent portion of the outlet tube closed off by the piston and so transport material from that space away through the outlet tube.

2. Apparatus according to Claim 1, wherein the member positioned within the inlet is a vibratory member operable to transmit vibratory forces to material entering the material aperture to assist the passage of the material therethrough.

3. Apparatus according to Claim 2, wherein the vibratory member is supported in spaced relationship to the body to define the material aperture and is mounted on a plurality of flexible mountings.

4. Apparatus according to Claims 2 or 3, wherein the vibratory member is vibrated by a pneumatically operated device including a vibrating element impelled to move relative to the vibratory member by air under pressure.

5. Apparatus according to any preceding claim, wherein the piston is tubular, first portions of the inner sidewall of the body define with the external sidewall surface of the piston a fluid-tight annular cavity, radial flange members on the external surface of the piston are in slidable fluid-tight engagement with the inner sidewall, and fluid supply conduits communicate with the cavity on opposite sides of said flange members so that supply of fluid under pressure to a respective one of said conduits can cause movement of the piston in a required direction between its extended and retracted positions.

6. Apparatus according to Claim 5, wherein second portions of the inner sidewall of the body define with the external sidewall surface of the piston a second annular cavity provided with a channel through which pressurised fluid can be supplied thereto, and bores with the lower portion of the piston are positioned and arranged to communicate the second annular cavity with the space within the body and adjacent portion of the outlet tube when the piston is in the fully extended position.

7. Apparatus according to Claim 6, wherein the bores in the lower portion of the piston are positioned axially to communicate with the second annular cavity only after the piston has passed a final portion of its travel towards the fully extended position in which the head of the piston has produced appreciable deformation of a resilient valve seat gasket and/or appreciable deflection of flexible mountings for the inlet member has taken place.

8. Apparatus according to any preceding claim, wherein the outlet tube is formed with an elbow or right-angled bend.

9. A valve assembly for handling powders, granules and the like flowable materials, sub stantially as hereinbefore described with refer ence to and as illustrated in the accompanying drawing.

10. A hopper or tank for powders, granules

and the like flowable materials, having a bottom discharge outlet to which is secured a valve as claimed in any preceding claims.

11. A hopper or tank as claimed in Claim 10, wherein the lower end of the valve is connected via a discharge pipe having an elbow or a right-angled bend to a generally horizontal trunk pipe.