GB2571823A

GB2571823A - Pinch valve

Info

Publication number: GB2571823A
Application number: GB1900564.4A
Authority: GB
Inventors: Francis Hesketh David
Original assignee: Spiroflow Ltd
Current assignee: Spiroflow Ltd
Priority date: 2018-01-15
Filing date: 2019-01-15
Publication date: 2019-09-11
Anticipated expiration: 2039-01-15
Also published as: GB201900564D0; GB2571823B

Abstract

Bulk-bag discharge flow control apparatus for controlling the size of a spout (26, Figure 1) opening from the bag to control rate of material discharge. The apparatus comprises first 42 and second 44 opposed angular pinch bars located in respective first and second vertically spaced adjacent horizontal planes to define a first enclosed, angular space. Third 46 and fourth 48 opposed angular pinch bars located in respective third and fourth vertically spaced adjacent horizontal planes collectively define a second enclosed, angular space. Each pinch bar may be controlled by respective first to fourth actuators adapted to move the first and second pinch bars relative to the third and fourth pinch bars to create first and second vertically spaced constrictions to create a moving column of material of a desired flowrate. Movement of the pinch bars may be controlled in relation to signals from load cells (20A,B). The pinch bars may be arcuate or V-shaped and may be mounted on respective rails 42A,B – 48A,B. Multiple such arrangements may control feed from bags (B Figure 6) to feed, via screw conveyors (84-94) and surge hopper (104), a further bag filling station (98). May be used in the mixing of compound pharmaceutical preparations.

Description

Pinch Valve

Technical Field and Background of the Invention

This application relates to bulk bags, and more specifically to the manner in which products stored in bulk bags are discharged. More specifically this application discloses and claims a multiple plane variable position pinch valve, a method for efficiently unloading bulk materials and a system for discharging bulk materials in a manufacturing environment.

Bulk bags of the type relevant to this application have a bottom spout on the bottom of the bulk bag that can be tied into a closed position or opened to allow the bag contents to flow from the bag. Bulk bags of this type and that are the subject of this invention are generally large, robustlyconstructed bags used to contain and transport powders, granules or flake materials. Depending on size, these bags are referred to as bulk bags, semi -bulk bags or super sacks.

These bags may be capable of holding a ton or more of content and therefore are normally transported by a fork lift truck, overhead crane, or chain hoist. Because of their size and weight they are attached to a lifting frame that supports and stabilizes the bag. The bags are typically suspended from the lifting frame by lifting straps attached to the bag. The frame and bag are loaded into a stationary discharge station that suspends the bag over a receptacle, such as a chute or hopper, into which the contents are allowed to flow by gravity. The bags are provided with an elongate discharge spout positioned in the bottom of the bag that is tied off with strings during filling, transport and storage. When the contents are to be emptied the tie strings are loosened so that the weight of the bag contents pushes open the discharge spout, allowing the contents to flow downwardly out of the bag, through the discharge spout and into the receptacle over which it is suspended.

There are several devices, generally referred to as “pinch valves” that are available and that utilize “pinch” or “control” bars to constrict the discharge spout opening and close the spout for the purpose of re-tying the spout, or to partially close the discharge spout in order to reduce material flow. However, there are inefficiencies and disadvantages inherent in these currently available devices that limit the degree of control over the rate of discharge and the ability to simply and safely open and close the tie strings of the bag, as needed.

There is a need for a pinch valve device that efficiently constricts the flow of material from the bulk bag discharge spout by using an apparatus that includes multiple sets of opposing pinch bars that open to the extent of the open bag spout, move towards each other with controlled movement, and are shaped to reduce the opening and constrict the discharge tube formed by the bag spout.

There is also a need for a method of efficiently constricting the flow of material from the bulk bag discharge spout that includes using multiple sets of opposing pinch bars that open to the extent of the open bag spout, move towards each other with controlled movement, and are shaped to reduce the opening and constrict the discharge tube formed by the bag spout.

Summary of the Invention

It is therefore an object of the invention to provide a controlled material feed from a bulk bag spout using actuated opposing pinch bars that are provided with individual position control.

It is therefore an object of the invention to provide controlled material feed from a bulk bag wherein the pinch bars are positioned on more than one plane, and provide multiple positions of bag spout restriction required to achieve a desired flow rate from the bag spout.

It is another object of the invention to permit the position of the pinch bars to be derived from a ‘loss in weight’ signal generated in real time as the bag contents are being discharged.

These and other objects and advantages of the invention are achieved by providing a bag discharge flow control apparatus for adjustably controlling the size of a spout opening in the bag to control the rate of discharge of material from bag. The flow control apparatus includes first and second opposed angular pinch bars that collectively define a first enclosed, angular space in first and second vertically spaced-apart adjacent horizontal planes, and third and fourth opposed angular pinch bars that collectively define a second enclosed, angular space in third and fourth vertically spaced-apart adjacent horizontal planes. Each of the first, second, third and fourth pinch bars are controlled by respective first, second, third and fourth actuators that are adapted to move the first and second pinch bars towards and away from each other and the third and fourth pinch bars towards and away from each other. The movement of the first and second pinch bars relative to the movement of the third and fourth creates first and second vertically spaced-apart constriction in a discharge spout of a bulk bag positioned in the first and second enclosed angular spaces to create a moving column of material. A plurality of load cells monitor weight reduction in the bag in real time as the bag contents flow from the bag through the discharge spout and provide output signals indicating the weight reduction. A control device receives the output signals from the load cells and feeds back control signals to the pinch bar actuators that move the pinch bars to control the size of the first and second vertically-spaced constrictions in the discharge spout in order to control the rate of discharge and induce movement of the column of material.

In accordance with another embodiment of the invention, the pinch bar actuators include position control feedback sensors that provide additional input changes to the control device and confirm the position of the pinch bars.

In accordance with another embodiment of the invention, A bulk bag discharge flow control apparatus for adjustably controlling the size of a spout opening in the bag to control the rate of discharge of material from the bag, comprising a base, a lower bag support structure, an upper bag support structure including a horizontal bag support with a spout opening into which the spout of the bag is positioned, and a frame for holding the bag in a vertical position. First and second opposed angular pinch bars are mounted in the upper bag support structure that collectively define a first enclosed, angular space in first and second vertically spaced-apart adjacent horizontal planes. Third and fourth opposed angular pinch bars are mounted in the upper bag support structure in vertically spaced-apart relation to the first and second pinch bars that collectively define a second enclosed, angular space in third and fourth vertically spaced-apart adjacent horizontal planes. The movement of the first and second pinch bars relative to the movement of the third and fourth creates first and second vertically spaced-apart constrictions in a discharge spout of the bag positioned in the enclosed angular space to create a moving column of material.

In accordance with another embodiment of the invention, each of the first, second, third and fourth pinch bars is controlled by respective first, second, third and fourth actuators adapted to move the first and second pinch bars towards and away from each other and the third and fourth pinch bars towards and away from each other.

In accordance with another embodiment of the invention, a plurality of load cells are positioned adjacent the pinch bars and adapted to monitor weight reduction in the bag in real time as the bag contents flow from the bag through the discharge spout and to provide output signals indicating the weight reduction.

In accordance with another embodiment of the invention, a control device is provided for receiving the output signals from the load cells and feeding back control signals to the pinch bar actuators that move the pinch bars to control the size of the first and second vertically-spaced constrictions in the discharge spout in order to control the rate of discharge and induce movement of the column of material.

In accordance with another embodiment of the invention, the first, second, third and fourth pinch bars are mounted on respective rails for translation movement by the respective first, second, third and fourth actuators.

In accordance with another embodiment of the invention, a material collection chute and clamping collar are positioned below and in line with the discharge spout of the bag.

In accordance with another embodiment of the invention, the first, second, third and fourth pinch bars are each arcuate, the first and second pinch bars oppose each other and define between them an opening that changes in size and shape as the first and second pinch bars move relative to each other, and the third and fourth pinch bars oppose each other and define between them an opening that changes in size and shape as the third and fourth pinch bars move relative to each other.

In accordance with another embodiment of the invention, the actuators comprise pneumatic cylinders.

In accordance with another embodiment of the invention, the first, second, third and fourth pinch bars are adapted to move to a position where there is no opening between the first and second pinch bars, and the third and fourth pinch bars are adapted to move to a position where there is no opening between the third and fourth pinch bars.

In accordance with a method according to the invention, a method of controlling the flow of contents from a bag is provided that includes the steps of providing first and second opposed angular pinch bars mounted in the upper bag support structure and that collectively define a first enclosed, angular space in first and second vertically spaced-apart adjacent horizontal planes, and third and fourth opposed angular pinch bars mounted in the upper bag support structure in vertically spacedapart relation to the first and second pinch bars that collectively define a second enclosed, angular space in third and fourth vertically spaced-apart adjacent horizontal planes. The first and second pinch bars are moved relative to the movement of the third and fourth to create first and second vertically spaced-apart constrictions in a discharge spout of the bag positioned in the enclosed angular space to create a moving column of material to thereby adjustably control the size of a spout opening in the bag to control the rate of discharge of material from the bag.

In accordance with another embodiment of the method, each of the first, second, third and fourth pinch bars is controlled by respective first, second, third and fourth actuators adapted to move the first and second pinch bars towards and away from each other and the third and fourth pinch bars towards and away from each other.

According to another embodiment of the invention, a system for controlling the discharge of contents from an array of bulk bags in a manufacturing operation is provided, and includes a plurality of bulk bag discharge flow control apparatuses for adjustably controlling the size of a spout opening in the bag to control the rate of discharge of material from the bag. Each of the apparatuses includes first and second opposed angular pinch bars mounted in the upper bag support structure that collectively define a first enclosed, angular space in first and second vertically spaced-apart adjacent horizontal planes. Third and fourth opposed angular pinch bars are mounted in the upper bag support structure in vertically spaced-apart relation to the first and second pinch bars that collectively define a second enclosed, angular space in third and fourth vertically spaced-apart adjacent horizontal planes. The movement of the first and second pinch bars relative to the movement of the third and fourth creates first and second vertically spaced-apart constrictions in a discharge spout of the bag positioned in the enclosed angular space to create a moving column of material. A respective plurality of conveyors are operatively connected to the bulk bag discharge flow control apparatuses for receiving material from the bulk bags under the control of the pinch bars and conveying the material to a downstream manufacturing system unit.

In accordance with another embodiment of the invention, the downstream manufacturing system unit includes a surge hopper for receiving materials received from the plurality of bulk bag discharge flow control apparatuses.

In accordance with another embodiment of the invention, the system includes a bag filling station for receiving materials from the surge hopper.

Brief Description of the Drawings

Figure 1 is an elevation view of a bulk bag discharge device according to an embodiment of the invention, and a table correlating reference numbers to elements of the invention;

Figure 2 is a fragmentary perspective view of the pinch bar assembly of the bulk bag discharge device;

Figures 3, 4 and 5 are top plan views of the pinch bar assembly showing the pinch bars in various positions within the range of movement of the pinch bars; and

Figure 6 is a perspective view of a manufacturing system that utilizes bulk bag unloading stations incorporating pinch bars according to an embodiment of the invention.

Description of the Invention

Referring now to the drawings, in Figure 1 a bag discharge device according to one embodiment of the invention is broadly shown at 10 and includes a base 12 that supports a lower bag support structure 14 and an upper bag support structure 16. The lower bag support structure 14 includes a horizontal bag support 19 with a spout opening 18 into which the spout 26 of a bag “B” is positioned.

Load cell assemblies 20A, 20B are positioned adjacent the horizontal bag support 19, as is a ground fault indicator 22. The bag discharge device 10 includes a top bag rigging frame 24 from which the bag “B” is suspended. A material collection chute 34 and clamping collar 36 is positioned below and in line with the spout 26. Electrical controls 30 are contained in a control housing 32.

Referring now to Figure 2, a pinch bar assembly 40 adjustably controls the size of the bag discharge spout 26 of the bag “B” to control the rate of discharge of material from bag “B ”

The assembly 40 includes first and second opposed angular pinch bars 42, 44 that collectively define a first enclosed, angular space in first and second vertically spaced-apart adjacent horizontal planes, and third and fourth opposed angular pinch bars 46, 48 that collectively define a second enclosed, angular space in third and fourth vertically spaced-apart adjacent horizontal planes. The angularity shown is arcuate, but other angular shapes, for example a “V” shape is also within the scope of the invention. Each of the first, second, third and fourth pinch bars 42, 44, 46, 48 are controlled by respective first, second, third and fourth actuators 50, 52, 54, 56, preferably pneumatic cylinders, that are adapted to move the respective first, second, third and fourth pinch bars 42, 44, 46, 48 towards and away from each other.

As also shown in Figure 2, the pinch bar 42 is mounted for translating movement on rails 42A, 42B; the pinch bar 44 is mounted for translating movement on rails 44A, 44B; the pinch bar 46 is mounted for translating movement on rails 46A, 446B; and the pinch bar 48 is mounted for translating movement on rails 48A, 48B.

The movement of the first and second pinch bars 42, 44 relative to the movement of the third and fourth pinch bars 46, 48 creates first and second vertically spaced-apart constrictions in the bag discharge spout 26 of the bulk bag “B” of Figure 1 to create a moving column of material having a desired flow rate. The load cells 20 monitor weight reduction in the bag “B” in real time as the bag contents flow from the bag “B” through the discharge spout 26 and provides output signals indicating the weight reduction. Controls 30 receive the output signals from the load cells 20 and feed back control signals to pinch bar actuators 50, 52, 54, 56 that move the pinch bars 42, 44, 46, 48 to control the size of the first and second vertically-spaced constrictions in the discharge spout 26 in order to control the rate of discharge and induce movement in movement of the column of material.

The advantage of individual controls for multiple opposing bars on different planes is to constrict the flow of material from the bag spout 26 in more than one place to create a moving column of material and possibly prevent material flow problems, or material leakage when a fully closed spout 26 is required. This can improve system accuracy.

The vertical position of the pairs of opposing pinch bars 42, 44 and 46, 48 can be variable to provide a defined column formed by the discharge spout 26. The maximum and minimum vertical distance is defined by the discharge spout 26 design and style. The advantage of creating a defined column in the discharge spout 26 is that it provides additional control of material flow from the bulk bag “B”. A third set of opposing actuators, not shown, can be included to pinch and condition the discharge spout 26 for the purpose of breaking up lumps or agglomerations of material. The variable position of each pinch bar 42, 44, 46, and 48 allows the creation of a restricted path for material flow with vertically out of phase deviations to the material flow path.

The position of the pinch bars 42, 44 and 46, 48 in various positions are shown in Figures 3, 4 and 5.

Referring now to Figure 6, a system for discharging bulk bags in a manufacturing environment according to one embodiment of the invention is explained. Note that the bulk bag discharge flow control apparatus according to the invention has application in a wide variety of manufacturing, industrial, scientific, medical and other environments, and the example described here is merely one example of many possible uses. The discharge system 70 broadly represents a process for accurately discharging predetermined quantities by weight of bulk materials to be mixed and used to, for example, compound pharmaceutical preparations. In the system 70 six bulk bag unloading stations 72, 74, 76, 78, 80 and 82 are arrayed to feed materials from bulk bags Bl, B2, B3, B4, B5 and B6 via tubular screw conveyors 84, 86, 88, 90, 92 and 94 to a centrally-positioned bag filling station 98. Bag filling station 98 includes a bag rigging access platform 100 that includes a support 102 for the screw conveyors 84, 86, 88, 80, 92 and 94, which discharge contents into a surge hopper 104. A sack tip station 106 discharges minor ingredients into the surge hopper 104 via an aeromechanical conveyor 108.

Each of the bulk bags Bl, B2, B3, B4, B5 and B6 are controlled by a bag discharge device 72A, 74A, 76A, 78A, 80A and 82A positioned beneath the respective bags Bl, B2, B3, B4, B5 and B6. Operation is as described above.

The surge hopper 104 is weighed by load cells, not shown as ingredients from the bags Bl, B2, B3, B4, B5 and B6 are fed by the conveyors 84, 86, 88, 80, 92, 94 and 108 into the surge hopper 104.

The surge hopper 104 is funnel-shaped and feeds into a bulk bag 110 that contains the accumulated ingredients discharged by the bulk bag unloading stations 72. Check weight load cells, not shown, determine the weight of ingredients discharged into the bulk bag 110.

The system 70 is itself an integral part of a larger manufacturing facility that may include both upstream and downstream equipment, which could include additional bulk bag discharge devices 72A, 74A, 76A, 78A, 80A and 82A discharging contents from other bulk bags.

A multiple plane variable position pinch valve, a method for efficiently unloading bulk materials and a system for discharging bulk materials in a manufacturing environment according to the invention have been described with reference to specific embodiments and examples. Various details of the invention description of the preferred embodiments of the invention and best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation, the invention being defined by the claims.

Claims

1. A bulk bag discharge flow control apparatus for adjustably controlling the size of a spout opening in the bag to control the rate of discharge of material from the bag, comprising:

a. first and second opposed angular pinch bars mounted in the upper bag support structure and that collectively define a first enclosed, angular space in first and second vertically spaced-apart adjacent horizontal planes; and

b. third and fourth opposed angular pinch bars mounted in the upper bag support structure in vertically spaced-apart relation to the first and second pinch bars that collectively define a second enclosed, angular space in third and fourth vertically spaced-apart adjacent horizontal planes; wherein

c. the movement of the first and second pinch bars relative to the movement of the third and fourth creates first and second vertically spaced-apart constrictions in a discharge spout of the bag positioned in the enclosed angular space to create a moving column of material.

2. A bag discharge flow control apparatus according to claim 1, wherein each of the first, second, third and fourth pinch bars is controlled by respective first, second, third and fourth actuators adapted to move the first and second pinch bars towards and away from each other and the third and fourth pinch bars towards and away from each other.

3. A bag discharge flow control apparatus according to claim 1 or 2, and including a plurality of load cells positioned adjacent the pinch bars and adapted to monitor weight reduction in the bag in real time as the bag contents flow from the bag through the discharge spout and to provide output signals indicating the weight reduction.

4. A bag discharge flow control apparatus according to claim 3, and including a control device for receiving the output signals from the load cells and feeding back control signals to the pinch bar actuators that move the pinch bars to control the size of the first and second vertically-spaced constrictions in the discharge spout in order to control the rate of discharge and induce movement of the column of material.

5. A bag discharge flow control apparatus according to claim 2, or claim 3 or 4 when dependent on claim 2, wherein the first, second, third and fourth pinch bars are mounted on respective rails for translation movement by the respective first, second, third and fourth actuators.

6. A bag discharge flow control apparatus according to any of the preceding claims, and including a material collection chute and clamping collar positioned below and in line with the discharge spout of the bag.

7. A bag discharge flow control apparatus according to any of the preceding claims, wherein the first, second, third and fourth pinch bars are each arcuate, the first and second pinch bars oppose each other and define between them an opening that changes in size and shape as the first and second pinch bars move relative to each other, and further wherein the third and fourth pinch bars oppose each other and define between them an opening that changes in size and shape as the third and fourth pinch bars move relative to each other.

8. A bag discharge flow control apparatus according to claim 2, or any of claims 3 to 7 when dependent on claim 2, wherein the actuators comprise pneumatic cylinders.

9. A bag discharge flow control apparatus according to claim 7, or claim 8 when dependent on claim 7, wherein the first, second, third and fourth pinch bars are adapted to move to a position where there is no opening between the first and second pinch bars, and further wherein the third and fourth pinch bars are adapted to move to a position where there is no opening between the third and fourth pinch bars.

10. A bulk bag discharge flow control apparatus for adjustably controlling the size of a spout opening in the bag to control the rate of discharge of material from the bag, comprising:

a. a base, a lower bag support structure, an upper bag support structure including a horizontal bag support with a spout opening into which the spout of the bag is positioned, and a frame for holding the bag in a vertical position;

b. first and second opposed angular pinch bars mounted in the upper bag support structure and that collectively define a first enclosed, angular space in first and second vertically spaced-apart adjacent horizontal planes; and

c. third and fourth opposed angular pinch bars mounted in the upper bag support structure in vertically spaced-apart relation to the first and second pinch bars that collectively define a second enclosed, angular space in third and fourth vertically spaced-apart adjacent horizontal planes; wherein

d. the movement of the first and second pinch bars relative to the movement of the third and fourth creates first and second vertically spaced-apart constrictions in a discharge spout of the bag positioned in the enclosed angular space to create a moving column of material.

11. A bag discharge flow control apparatus according to claim 10, wherein each of the first, second, third and fourth pinch bars is controlled by respective first, second, third and fourth actuators adapted to move the first and second pinch bars towards and away from each other and the third and fourth pinch bars towards and away from each other.

12. A bag discharge flow control apparatus according to claim 10 or 11, and including a plurality of load cells positioned adjacent the pinch bars and adapted to monitor weight reduction in the bag in real time as the bag contents flow from the bag through the discharge spout and to provide output signals indicating the weight reduction.

13. A bag discharge flow control apparatus according to claim 12, and including a control device for receiving the output signals from the load cells and feeding back control signals to the pinch bar actuators that move the pinch bars to control the size of the first and second vertically-spaced constrictions in the discharge spout in order to control the rate of discharge and induce movement of the column of material.

14. A bag discharge flow control apparatus according to claim 11, or claim 12 or 13 when dependent on claim 11, wherein the first, second, third and fourth pinch bars are mounted on respective rails for translation movement by the respective first, second, third and fourth actuators.

15. A method of controlling the flow of contents from a bag, comprising the steps:

a. providing first and second opposed angular pinch bars mounted in the upper bag support structure and that collectively define a first enclosed, angular space in first and second vertically spaced-apart adjacent horizontal planes;

b. providing third and fourth opposed angular pinch bars mounted in the upper bag support structure in vertically spaced-apart relation to the first and second pinch bars that collectively define a second enclosed, angular space in third and fourth vertically spaced-apart adjacent horizontal planes;

c. moving the first and second pinch bars relative to the movement of the third and fourth to create first and second vertically spaced-apart constrictions in a discharge spout of the bag positioned in the enclosed angular space to create a moving column of material to thereby adjustably control the size of a spout opening in the bag to control the rate of discharge of material from the bag.

16. A method according to claim 15, wherein each of the first, second, third and fourth pinch bars is controlled by respective first, second, third and fourth actuators adapted to move the first and second pinch bars towards and away from each other and the third and fourth pinch bars towards and away from each other.

17. A system comprising one or more bulk bag discharge flow control apparatuses as claimed in any of claims 1 to 14, wherein the system further includes one or more conveyors, one or more downstream manufacturing system units, or a combination thereof.

18. A system for controlling the discharge of contents from an array of bulk bags in a manufacturing operation, comprising:

a plurality of bulk bag discharge flow control apparatuses for adjustably controlling the size of a spout opening in the bag to control the rate of discharge of material from the bag, each of the apparatuses comprising:

first and second opposed angular pinch bars mounted in the upper bag support structure and that collectively define a first enclosed, angular space in first and second vertically spaced-apart adjacent horizontal planes; and third and fourth opposed angular pinch bars mounted in the upper bag support structure in vertically spaced-apart relation to the first and second pinch bars that collectively define a second enclosed, angular space in third and fourth vertically spaced-apart adjacent horizontal planes; wherein the movement of the first and second pinch bars relative to the movement of the third and fourth creates first and second vertically spaced-apart constrictions in a discharge spout of the bag positioned in the enclosed angular space to create a moving column of material; and a respective plurality of conveyors operatively connected to the bulk bag discharge flow control apparatuses for receiving material from the bulk bags under the control of the pinch bars and conveying the material to a downstream manufacturing system unit.

19. A system according to claim 18, wherein the downstream manufacturing system unit comprises a surge hopper for receiving materials received from the plurality of bulk bag discharge flow control apparatuses.

20. A system according to claim 18 or 19, and including a bag filling station for receiving materials from the surge hopper.