GB2125015A

GB2125015A - Lifting and guiding apparatus for e.g. a valve for discharging a silo

Info

Publication number: GB2125015A
Application number: GB08321218A
Authority: GB
Inventors: Alan Williams
Original assignee: Simon Solitec Ltd
Current assignee: Simon Solitec Ltd
Priority date: 1982-08-12
Filing date: 1983-08-05
Publication date: 1984-02-29
Also published as: GB8321218D0

Abstract

An actuator for a discharge valve (18) for e.g. a silo comprises means for elevating and guiding an upper plate (21), carrying the conical valve (18), relative to a support member (17). An air bag (19) elevates plate (21) and valve (18) to permit material discharge, whilst four pairs of articulated arms (24) prevent the plate and the valve member from tilting during travel. A vibrator (28) may be mounted on plate (21), and the arms (24) may be in the form of plates whose travel is limited by strips (31) and pins (32), Fig. 3, not shown. <IMAGE>

Description

SPECIFICATION A material discharge device This invention concerns an actuator, particularly though not exclusively for material discharge apparatus of the kind wherein materials stored in a silo, or simply heaped above a receiving station, can be discharged in a controlled manner by means of a valve member, usually of upright conical form and adapted to rise and fall relative to a discharge opening or passage means, to form an annular aperture through which the material can flow. It is common in this kind of apparatus for the valve member to be seated peripherally on an inverted conical wall portion at the base of a silo or bin, and for the latter to be transportable between a filling station and the discharge location.

Many devices have been proposed for elevating the valve member, including hydraulic or pneumatic piston and cylinder devices, pneumatic bellows and electrical solenoid devices. The choice of device is not substantially influenced by, nor forms a significant part of the present invention.

It is an object of this invention to provide an actuator including a device to be elevated such as the valve member in material discharge apparatus, and means to ensure that the device is prevented from tilting in any position throughout its travel.

According the present invention, there is provided an actuator comprising a support member, a device adapted selectively to rise and fall relative to said support member, and lifting means between said support member and said device to raise the latter; characterised in that the device is connected to the support member by a plurality of articulated arms each being pivotally connected to the device and to the support member, said arms being arranged around said lifting means and attached to said device and said support member in such a manner that the device is maintained level by said arms and thus prevented from tilting in any position throughout its travel with respect to the support member.

Preferably, there are a plurality of pairs of articulated arms, each pair being hingedly attached together at one end of each arm, the opposite end of one arm being hingedly attached to the device whilst the corresponding opposite end of the other arm is hingedly attached to the support member.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a vertical section through a material discharge apparatus made in accordance with the invention; Figure 2 is a plan view thereof with a part removed for the purpose of illustration; and Figure 3 is a more detailed view of part of the arrangement illustrated in Fig. 1.

Referring now to the drawings, the material discharge apparatus comprises an annular collar 10 through which material can discharge from above into a receiving chute or hopper 11. At the upper extremity of the collar 10 is a member 1 2 which presents a short inclined or inverted frusto-conical flange 1 3. In practive, the flange 1 3 may form an extension of an inverted conical wall portion of a silo or bin mounted above the apparatus, as indicated by the dotted line 14. Rigidly attached to the collar 10 is a support structure consisting of a base plate 1 5 mounted above a housing 1 6 which is attached via a number of radial struts 1 7 to the wall of the collar.

A valve member 1 8 in the form of an upright conical shell is mounted for vertical movement with respect to the base plate 1 5 of the support structure by means of an air bag 1 9 supplied with compressed air via a unit 20 contained within the housing 1 6. The air bag 1 9 serves to raise and lower a plate 21 to which the valve member 18 is fixed by means of an upstanding collar 22. Thus by inflating the air bag 1 9 the valve member 1 8 can be raised to present an annular opening between its periphery and the surface of the flange 13, for the discharge of material present above the valve member 18, downwardly into the chute 11. The degree of elevation is variably controlled by unit 20.A rubber or other flexible material diaphragm 23 prevents any material from entering the area immediately beneath the valve member 1 8.

In order to ensure that the valve member 1 8 cannot tilt throughout its vertical movement, there are provided four pairs of articulated arms or leaves 24. In each pair, the leaves are hingedly connected together at 25 at one end, and the upper leaf of the pair is hingedly connected at 26 at its other end to the plate 21 whilst the lower sleeve is hingedly connected at 27 at its opposite end, to the plate 15. The plates 15 and 21 are rectangular in shape and along each face thereof there is provided one pair of leaves 24 such that the valve member is maintained level and prevented from tilting at any position throughout its travel.

In an alternative arrangement, the plates 1 5 and 21 may be triangular thus requiring only three pairs of hinged leaves 24, although greater stability is achieved with the arrangement illustrated.

Furthermore, in place of the two leaves of each pair, a single leaf could be hingedly attached to one or other of the plates 15, 21, the other end of the single plate being pivotally mounted on and slidable relative to the other of the plates, though again, greater stability is provided by the arrangement illustrated. In a still further alternative arrangement, one pair of leaves 24, or two adjacent pairs may be replaced by rods connected to and disposed at right angles to one of the plates 15, 21 and adapted to slide within sleeves fixed with respect to the other of said plates.

To assist discharge of materials which might tend to bridge across the annular opening provided by elevation of the valve member, a vibratory motor 28 is mounted on plate 21, preferably to effect oscillation of the valve member 1 8 in a vertical plane with respect to the supporting structure. The motor 28 may be driven electrically or by fluidic drive means.

Referring now to Fig. 3, which shows a part of the arrangement of Fig. 1 with the air bag 1 9 inflated, there may be provided at the hinged connection 25 of each pair of leaves 24, a device which prevents the leaves extending fully to a vertical attitude and thus limits the travel of plate 21 with respect to plate 1 5. This device consists of an angled strip 31 which passes inwardly around hinge 25 and protrudes outwardly through slots 30 above and below the latter in the central region of the leaves 24. Pins 32 attached to the leaves 24 and bridging the slots 30, pass through elongate slots 33 disposed generally vertically in the strip 31 wherein it protrudes through slots 30. Therefore it will be seen that upon pivotal movement of the arms 24 during raising and lowering of plate 21, the pins 32 can move freely within slots 33 within limits defined by the lengths of the slots 33. Preferably, the geometry of the strip 31 and the parts with which it interacts is such that elevation of plate 21 is arrested prior to pins 32 reaching the ends of their associated slots 33. In this way, strain on hinges 25 is minimised. The limiting strips 31 can be provided on all four pairs of leaves 24 or simply on the two opposed pairs illustrated in Fig. 3.

Claims

1. An actuator comprising a support member, a device adapted selectively to rise and fall relative to said support member, and lifting means between said support member and said device to raise the latter; characterised in that the device is connected to the support member by a plurality of articulated arms each being pivotally connected to the device and to the support member, said arms being arranged around said lifting means and attached to said device and said support member in such a manner that the device is maintained level by said arms and thus prevented from tilting in any position throughout its travel with respect to the support member.

2. An actuator according to Claim 1, including a plurality of pairs of articulated arms each pair being hingedly attached together at one end of each arm, the opposite end of one arm being hingedly attached to the device whilst the corresponding opposite end of the outer arm is hingedly attached to the support member.

3. An actuator according to Claim 1 or Claim 2, including means to limit the degree of pivotal movement of at least some of said arms with respect to the parts to which they are pivotally attached thus to limit the degree of elevation of said device relative to said support member.

4. An actuator according to Claim 3, in which said limiting means comprises a strip wrapped internally around the pivotal axis of a pair of articulated arms and having portions protruding externally through slots in the latter, there being elongate slots in said strips through which pass pins bearing externally on said arms, said pins sliding in said elongate slots during pivotal movement of said arms.

5. An actuator according to any preceding claim, when incorporated in material discharge apparatus comprising means defining a passage through which material can discharge, said supporting member being fixed with respect to said passage means, said device constituting a valve member adapted selectively to rise and fall relative to the support member and interacting with said passage means to control the discharge of material through said passage, at least some of said articulated arms being pivotally connected to said valve member to prevent the latter from tilting as it is raised relative to said passage means.

6. An actuator according to any preceding claim, in which said lifting means is in the form of an inflatable air bag.

7. An actuator according to Claim 6, wherein said air bag is fixed to and disposed between a pair of superimposed rectangular plates, there being four pairs of articulated arms each pivotally attached to one corresponding pair of the sides of said plates.

8. An actuator according to Claim 5, including a vibrator attached to said valve member to cause oscillation thereof on an axis parallel to its direction of elevation by said lifting means.

9. An actuator according to Claim 5, wherein said valve member is an upright conical shell whose periphery bears against said passage means when said device is lowered, and when said lifting means is variable in operation thus to control the degree of elevation of said valve member.

10. An actuator according to Claim 5, including a flexible diaphragm attached to the peripheral region of said valve member, and to said support member thus to prevent material from entering the area immediately beneath the valve member.

11. An actuator according to Claim 1, wherein each articulated arm is pivotally attached at one end alternatively to the support member or to the device, with the other end pivotally mounted on and slidable relative to the other of said alternative parts.