GB2137159A

GB2137159A - Emptying a Flexible Lining of a Container

Info

Publication number: GB2137159A
Application number: GB08308950A
Authority: GB
Inventors: Ladislav Stephan Karpisek
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-03-31
Filing date: 1983-03-31
Publication date: 1984-10-03
Also published as: GB8308950D0; GB2137159B

Abstract

An apparatus to empty a flowable substance from a flexible liner 13 housed in a rigid container through an aperture G in a side of the container comprises a pivotable container support 1, 2 to locate the bottom of the container and an arched member having a top 7 joined by two legs 5 pivotally connected to the container support with an axis of pivoting 6 parallel to the axis 3 of pivotting of the container support, spring means 9 being provided to bias the arched member in the direction of potential downhill inclination of the container support. The liner neck 15 passes over the arched member and is attached to the container 16. The liner has an initially backed up lower discharge portion which discharges through flaps F of the container, and door G of the support. The arched member stretches the liner by pivotting about axis 6 to facilitate complete emptying of the liner. <IMAGE>

Description

SPECIFICATION Bag Extractor This invention relates to a method and apparatus to discharge flowable non-liquid material from a plastic film liner housed in a rigid walled container.

The use of a liner in a container makes the storage and transport of powder and granular materials possible without the materials becoming contaminated by direct contact with the inner surfaces of the container and if the liner is closed there is no possibility of foreign matter accidentally mixing with the materials during storage and transport.

The method and apparatus is for use with a rigid walled container of rectangular section with four walls, an open top and a bottom with an opening panel in one side adjacent the container bottom. Whilst the concept of using a liner and discharging the contents through an opening panel of the container is excellent some products flow more readily than others and for that reason the practical application of the concept has not always been fully successful. Examples of substances that have proved difficult to discharge are milk powder and flour. With such products there is a residue after gravitational discharge ceases and the removal of that residue is time consuming and annoying to the operator.

By means of the method hereinafter described and the use of apparatus as set out herein, substantially complete discharge of the contents of a liner housed in a container having a side discharge opening can be achieved.

The method of this invention can be broadly stated as providing substantially complete discharge of a flowable substance from a flexible liner housed in a rigid container through a mouth at one end of the liner juxtaposed a closable aperture in a first side of the container, said method comprising the steps of locating the container between a pair of interconnected and pivotally anchored legs of an arched member so that the direction of intended discharge of the substance from the container is substantially normal to the axis of the pivoting of the arched member, pivoting the arched member to locate a top part of the arched member in a first position adjacent another side of the container which is opposite to said first side wall, anchoring the other end of the liner so that the weight of contents retains the arched member in the operative position, opening the container aperture, placing the mouth of the liner in an open condition in the opened container aperture so that said substance can gravitationally discharge from the bag, and applying an elongating force through the arched member to the liner by means of the application of a biassing force to the arched member tending to pivot it towards said first container side.

Apparatus provided by this invention can be broadly defined as apparatus to empty a flowable substance from a flexible liner housed in a rigid container through an aperture in a side of the said container, said apparatus comprising an arched member with legs and adapted to straddle the container, pivotal mounting on the arched member legs so the arched member can move to and fro between a first and a second position, the biassing means to bias the arched member towards the first position.

The method of the invention and apparatus in accordance with the invention will now be described with reference to the accompanying drawings in which: Fig. 1 is a side view schematically showing a presently preferred form of apparatus; Fig. 2 is a view similar to Fig. 1 with portion of the container removed to permit the form of a filled liner bag to be studied; Fig. 3 is a view similar to Fig. 2 showing a stage in the progressive emptying of the liner bag; Fig. 4 is a view similar to Fig. 3 showing a further stage in the emptying of the liner bag and is at the stage of balance between the forces acting on the liner bag and the weight of the liner bag and its remaining contents; Fig. 5 is a view similar to Fig. 4 showing a further stage in the emptying process; Fig. 6 is a view similar to Fig. 5 but showing the liner bag in the completely empty condition;; Figs. 7, 8 and 9 show different alternate forms of apparatus; Fig. 10 is a perspective view of a roller assembly; and Fig. 11 is a schematic side view of apparatus for use with the roller of Fig. 10.

Apparatus to put the method of the invention into effect may take a number of forms but the most versatile and presently preferred will be described first with reference to Figs. 1 to 6 where the liner is in the form of a bag.

In Fig. 1 there is shown a support structure having a base part 1 and an upright part 2. There is a pivot connection at 3 whereby the support structure can be rotated relative to the floor or some non-moving member so that the surface of the part 1 can be located at an angle to the horizontal. A prop 4 is provided so the part 1 will be horizontal when not in use and during the loading and removal of a container from the support structure.

An inverted U frame with legs 5, pivotally connected at 6 to the part 1, has a base 7 on which there is a roller 8. The U frame is shown in Fig. 1 in its preferred inoperative position although other inoperative positions may be occupied, i.e. hard left or hard right. The axis of pivot of the frame is parallel to the axis of pivot of the support structure. Tension springs 9 connect arms 10, fixed to the U legs 5, to the floor 11 or some non-moving member, e.g. a stand raising the support structure above floor level.

As illustrated, a pallet mounted cage 12 fitted with an inner skin of panels and a liner bag 13 therein, is mounted on the part 1 and rests against the part 2. The cage skin assembly of Fig.

2 is shown diagrammatically with a cage wall removed so the outline of a filled liner bag 3 can be seen. It has a trunk part 14 to discharge the bag contents which projects through openable flaps F of the cage inner skin and door G of the cage.

Fig. 2 also shows a completed first step in the emptying method to be described below. This step involves the attachment of the open upper end 15 of the bag 13 to the cage 12 at the position indicated 1 6. The bag 13 passes over the roller 8 and retains the U frame in the illustrated position with the roller in juxtaposition to the bag wall of the cage 12. At this stage the springs 9 are slightly tensioned due to pivoting, from the Fig. 1 position, of the U frame.

The method of the invention as it relates to the emptying operation involves the steps of raising the rear edge of the support structure by pivoting it about the pivot connection 3, this can be done before or after the release of the bag trunk 14 through the cage door and inner skin flaps, as desired. The effect of this is to fully tension the springs 9 so that a bias is created which tends to pivot the U frame about the pivot points 6 towards the part 2 of the support structure and so apply a bag elongating force.

Emptying will commence under the effect of gravity as soon as the bag trunk is made free for this purpose and will continue with the liner bag taking up a member of configurations as it becomes emptier, some such configurations are as shown in full lines Figs. 3 and 4. Fig. 4 is intended also to illustrate the balance condition which is reached when the weight of the bag 13 and the remaining contents in on the verge of equalling the spring forces applied to the U frame.

As this balance condition is passed, due to the discharge of additional contents, the springs 9 cause the U frame to pivot in an anti-clockwise direction progressing to the configuration shown in Fig. 5 where the contents C is being dragged to the discharge point by the movement of the U frame and ultimately that shown in Fig. 6, where all of the contents of the liner bag 13 has been discharge.

It is clear from what has been described above that the invention involves a method which applies a bag elongating force to the bag during an emptying operation, and which when fully effective brings the inner surfaces of the bag together in a manner causing the contents of the bag to flow therefrom through an opening in the container.

The apparatus detailed above may be modified in several ways whilst still allowing the invention to be performed. For example, see Fig. 7 where no support structure is shown. The apparatus illustrated could operate with easy flowing material such as spherical pellets of plastic raw material as supplied for plastics moulding machines. Such pellets have a very low angle of repose and there would probably be no need for the tilting of the container in order to achieve a level of residual material in the liner bag capable of being moved by the springs acting on the U frame. The apparatus may be pivotally fixed to a floor and the container located on the floor under the frame. In another configuration the arched U frame can be pivotally connected to brackets clampable to the container and applied thereto in any location of the container.

Figs. 8 and 9 illustrate two possible configurations which by appropriate positioning of the pivot points for the U frame would enable the method of the invention to be carried out.

Whist tension springs have been shown in the drawings, located in several positions, torsional springs of appropriate strength would also be effective. It is also envisaged that dead weights could be used, solely or to assist springs. Dead weights have application where the apparatus is in an elevated position, as for example over the mouth of an elevated hopper. Piston and cylinder combinations may be used to move the U frame and/or apply the biassing means for the U frame as an alternative or to supplement the above biassing means.

In variations of the method the attachment of the liner bag end 1 5 at the position 16 could be by strong, but perhaps slightly elastic, straps.

These straps could extend from the end 1 5 of the liner bag over the roller 8 to be fastened to the cage at 16. The end 15 of the bag can be directly fastened to the cross-bar of the U frame which would not require a roller as previously described, see Fig. 9.

In another variation the front 1 7 of the liner bag 13 could be attached to the front of the cage as at 18, see Fig. 2, to prevent the liner bag front part 17 falling into the cage inner liner as emptying proceeds, except as shown in broken outline.

In another variation of the constructions herein described the connection of the U frame legs 5 to its support, say the member 1, can be through intermediate members, see Fig. 1, inset, where such members 19 are of angle formed and the legs 5 are pivotally connected thereto at 6a. This allows the U frame to pivot fully forward in the anti-clockwise direction, as is desirable in some operations, but is limited in its movement in the clockwise direction by the upright part 20. Such an arrangement also simplfies the mounting of the biassing means, see Fig. 1, where the biassing means is shown for the purpose of this explanation as having reached an inoperative condition before the U frame has moved fully to the left.

Means to tilt and retain a tilted assembly in place has not been disclosed in detail, several possible means can be envisaged. Figs. 10 and 11 show an alternative arrangement in which an operative component can be mounted in working relationship with the liner before the container is raised to a working position where emptying will be performed. In many such positions there is insufficient room to fasten the liner bag over a U frame in the manner previously discussed. With the present proposal there is a pair of legs 22 with hooked elements 23 to support the ends of a shaft 24 on which there is mounted a pair of rollers 25.

The arrangement as described makes it possible to position a container/pallet assembly, already provided with roller assembly secured below an end of the liner 13 as shown in Fig. 2, in an elevated pallet support of an unloading station.

The pallet support has the pair of legs 22 and the container is positioned therebetween. Then by means of a rope or the like a rearward force is applied to the legs 22. The ramps 26 of the hooked elements 23 pass below the ends of the shaft 24 elevating it and allowing it to drop into the hooked elements where it is retained during the liner emptying process.

With the arched frame of the first embodiment it is necessary for the operator to mount the unloading station and pull back the arch member and fasten the liner end 5 to the enclosure side 2.

This is not always convenient and is sometimes impossible due to the limited working space on some unloading stations. The advantages of the removable roller assembly as proposed by this invention are at once clear.

Claims

1. A method of substantially completely discharging a flowable substance from a flexible liner housed in a rigid container through a mouth at one end of the linerjuxtaposed a closable.

aperture in a first side of the container, said method comprising the steps of locating the container between a pair of interconnected and pivotally anchored legs of an arched member so that the direction of intended discharge of the substance from the container is substantially normal to the axis of the pivoting of the arched member, pivoting the arched member to locate a top part of the arched member in a first position adjacent another side of the container which is opposite to said first side wall, anchoring the other end of the liner so that the weight of contents retains the arched member in the operative position, opening the container aperture, placing the mouth of the liner in an open condition in the opened container aperture so that said substance can gravitationally discharge from the bag, and applying an elongating force through the arched member to the liner by means of the application of a biassing force to the arched member tending to pivot it towards said first container side.

2. A method as claimed in claim 1 wherein the said other end of the liner is anchored to the container other side.

3. A method as claimed in claim 1 wherein the said other end of the liner is anchored to the arched member.

4. A method as claimed in any one of claims 1 to 3 including the additional steps of providing a pivotally movable container support structure with an axis of pivot parallel to the axis of pivot of the arched member and pivoting the support structure to provide a downward inclination to the horizontal from the bottom of the container towards the container aperture.

5. A method as claimed in any one of claims 1 to 4 including the additional step of restraining the liner wall adjacent the first container side from falling away from the first container side during the emptying of the liner.

6. Apparatus to empty a flowable substance from a flexible liner housed in a rigid container through an aperture in a side of the said container, said apparatus comprising an arched member with legs and adapted to straddle the container, pivotal mountings on the arched member legs so the arched member can move to and fro between a first and a second position, and biassing means to bias the arched member towards the first position.

7. Apparatus as claimed in claim 6 wherein the pivotal mountings on the arched member legs are adapted to be releasably coupled to said container.

8. Apparatus as claimed in claim 6 wherein the pivotal mountings on the arched member legs connect the arched member to a stand on which the container can be mounted.

9. Apparatus to empty a flowable substance from a flexible liner housed in a rigid container through an aperture in a side of the container, said apparatus comprising a container support pivotally movable to locate the bottom of a container when mounted thereon in a plane at an angle to the horizontal, an arched member having a top joined by two legs pivotally connected to the container support with an axis of pivoting parallel to the axis of pivot of the container support in the direction of potential downhill inclination of the container support.

10. Apparatus as claimed in claim 9 wherein the container support includes a support surface on which a container can sit and locating means to prevent a container sliding down the support surface when inclined.

11. Apparatus as claimed in any one of claims 6 to 10 including roller means extending between two legs of the arched member, an arm extending from each of said legs and biassing means connected to the arms to exert a force on the arched member to cause it to pivot.

12. Apparatus as claimed in any one of the preceding claims wherein the biassing means is a means selected from the following:-- tension springs, compression springs, torsion springs, weights, or piston and cylinder combination(s); either singly or in combination.

1 3. Apparatus as claimed in any one of Claims 6 to 12 wherein the arched member legs are pivotally connected to intermediate members pivotally movable towards both said first and second positions, said intermediate member including stop means to limit the amount of relative movement of the arched member legs relative to the intermediate members.

14. Apparatus as claimed in any one of claims 6 to 1 3 wherein the arched member comprises two uprights and a removable roller means joining the uprights.

1 5. A method of discharging a flowable substance as hereinbefore described with reference to the drawings.

1 6. Apparatus to discharge a flowable substance as hereinbefore described with reference to the drawings.