GB2207955A

GB2207955A - Fluid control or metering

Info

Publication number: GB2207955A
Application number: GB08817055A
Authority: GB
Inventors: Kelvin Taylor Robertson
Original assignee: ROMECH
Current assignee: ROMECH
Priority date: 1987-08-08
Filing date: 1988-07-18
Publication date: 1989-02-15
Anticipated expiration: 2008-07-18
Also published as: GB2207955B; GB8718846D0; GB8817055D0

Abstract

A valve plate 20 is pivoted in a clockwise direction until a kidney shaped opening (22) therein is almost out of register with an outlet passage 12A while still in communication with an inlet 10A. A reduced pressure is then applied to the opening (22) by retracting a piston 16. This causes fluid e.g chocolate to move in through the inlet and to hold any chocolate at the outlet thus preventing drip. The valve plate is then pivoted in an anti-clockwise direction to align the outlet 12A with the kidney shaped opening while closing the inlet 10A. An increased pressure is then applied to the opening 22 by moving the piston 16 forward to dispense chocolate through the outlet passage 12A. Alternatively, when the increased pressure is applied, the inlet opening 10A can remain partially or completely in communication with the opening 22 to allow some or all of the chocolate to return through the inlet passage 10A to thereby meter the amount of chocolate actually dispensed. <IMAGE>

Description

FLUID CONTROL OR METERING.

The present invention relates to a control or metering assembly for fluid and to a method of controlling or metering fluid and is particularly, although not exclusively applicable to coating of foodstuffs with material In a fluid state.

In a known arrangement for coating a serles of cakes with chocolate or cream, for instance, the cakes are moved on a conveyor beneath a chocolate dispenser which deposits a predetermined amount of chocolate over the cake. The valve for supplying the chocolate comprises a pivotally mounted cylindrical valve member located in a cylindrical bore. The cylindrical bore has an Inlet opening onto the top of the valve member, a reciprocal piston at the side and an outlet at the bottom. The valve member includes a passage which extends to the cyllndrical surface of the valve member at locations spaced at 900 relative to the pivotal axis.

In use, the valve Is located so that It communicates with the inlet and the piston. The piston is then moved away from the valve member to draw chocolate into the passage in the valve member and Into space vacated by the piston. The valve member Is then rotated through 900 so that Its passage communicates with the outlet and the piston. The piston Is then moved towards the valve member to cause chocolate to be discharged through the outlet. The valve member Is then returned to be In communication with the inlet and piston and the above described sequence is repeated.

When the chocolate has left the outlet It passes through a passage before being discharged onto the cake. It will be appreclated that the chocolate in that passage would tend to drip down when It Is not being positively discharged by the piston. Furthermore, the amount of chocolate dripping down between positive discharges would vary depending upon the amblent conditions and thus the amount of chocolate which Is positively discharged would vary leading to variations in product quality. Accordingly a separate piston Is connected to the outlet passage in order to apply a back pressure to the chocolate In that passage to help prevent It from dripping. However, there is no provision to take into account the variation in viscosity of the fluid which would affect the tendency of the fluid to drip.

The provision of the separate pistons Is expensive to manufacture and install and Increases the maintenance of the coating arrangement.

A further disadvantage Is that, for a given stroke of piston it is not possible to vary the amount of fluid discharged from the valve. Such a variation may be desirable either from the polnt of view of the amount of fluid required to be deposited or from variations in the operating conditions such as the head of fluid to the Inlet or the viscosity of the fluid.

According to one aspect of the present invention a method of controlling or meterlng fluid flow through a valve means vla an in let to the valve means and an outlet from the valve means with the valve means being movable relative to the Inlet and outlet and being capable of occupying a position In which the passage of the valve means Is In communication with both the Inlet and the outlet comprises selectively applying a reduced or an increased pressure to the valve means by a pressure Inducing means with the valve means being in the position In which its passage Is in communicatlon with both the Inlet and the outlet durlng at least part of the time when the pressure Inducing means is applying the Increased pressure to the valve means and varying the area of communication of the passage with at least one of the In let or outlet to control or meter the fluid flow.

The area of communicatlon of the passage with both the Inlet and the outlet may be varied to control or meter the fluid flow.

The pressure inducing means may be arranged to apply an Increased pressure with at least some of the fluid being returned through the Inlet. In this way, for instance for a given stroke of piston, the amount of fluid being dispensed through the valve means may be variable. When an increased pressure is applied to the valve means by the pressure inducing means no fluid may be arranged to pass through the outlet. Accordingly, when It Is not desired to dispense any fluid, there Is no need to discontinue the action of the pressure inducing means. The outlet may be closed when the pressure Inducing means applies an increased pressure.

Alternatively, when the pressure inducing means exerts an increased pressure, no fluid may be passed back through the inlet, in which case the Inlet may be closed.

The outlet may be in communication with the passage when the pressure Inducing means applies a reduced pressure, and the area of communication of the outlet with the passage may be variable under those conditions.

The valve means may be pivoted relative to the In let and outlet.

The pressure Inducing means may comprise a reciprocal piston. The piston may travel a fixed distance In either direction when an Increased or a decreased pressure is applied.

The method may comprise controlling or metering the fluid in dependence upon the amount of fluid required to leave the outlet or, alternatively or additionally, In dependence upon the ambient conditions, such as the pressure of the fluid to the inlet or the temperature or the viscosity of the fluid.

According to another aspect of the present Invention a control or metering assembly for fluid Includes an In let and an outlet and valve means movable relative to the In let and outlet, and pressure Inducing means arranged to co-operate with the valve means, the pressure inducing means being arranged to provide an increased or a reduced pressure to the valve means, the valve means being capable of occupying a position relative to the in let and outlet in which, when the pressure Inducing means appi les an increased pressure, the area of communication of a passage of the valve means with at least the inlet or the outlet Is variable.

The area between the inlet or, alternatively or additionally, the outlet and the passage of the valve means may be adjustable.

When a reduced pressure Is applied to the valve means and the passage of the valve means is In communication with the outlet, fluid at the outlet may be capable of belng held In place and, when the passage of the valve means Is In communicatlon with the in let and a reduced pressure is applied to the valve means, fluid may be arranged to be drawn in through the Inlet.

When the passage In the valve means is in communicatlon with the outlet and an Increased pressure Is applled by the pressure inducing means, fluid In the valve means may be arranged to be discharged through the out let.

The valve means may be pivotally mounted.

One side of the passage in the valve means may be in communicatlon with the pressure inducing means and the other side of the passage may be capable of communicating with both the in let and the outlet.

The pressure Inducing means may include a reciprocally mounted piston.

The pressure Inducing means may be arranged to exert an increased pressure on the valve means, and at least some or all of the fluid may be arranged to be returned through the Inlet.

The present Invent ion also Includes a control or mitering assembly when used in a method of controlling or meterlng fluid as herein descrlbed.

The invention may be carried into practice In varlous ways, but one embodiment will now be described by way of example and with reference to the accompanying drawings In which: Figure 1 Is a side view of a deposit head valve assembly, and Figure 2 is an end vlew of a valve plate Incorporated in the assembly shown in Flgure 1.

As shown In Figure 1, the assembly includes an Inlet 10 and an outlet 12 which are secured to one side of a valve housing 14. A reciprocal piston 16 is secured to the other side of the housing 14, with movement of the piston being controlled by an actuator 18.

The valve housing 14 Includes a pivotally mounted valve plate 20 which Includes a circumferential ly extending kidney shaped opening 22, as shown In Figure 2, and a radially extending slot 24.

When the valve plate 20 is In the position shown in Figure 2, with the kidney shaped opening 22 extending equally above and below a horizontal line extending through the pivotal axis 26 of the plate, the Inlet and the outlet both communicate with the kidney shaped openings via passages iOA and 12A extending through a wall 25 and the main block 28 of the valve housing. The reciprocal piston communicates with the central region of the kidney shaped opening (when in the position shown In Figure 2) via a passage 16A extending through a wall 30 of the valve housing.

Pivotal movement of the valve plate Is afforded by a reciprocal rod 32 which extends through an opening in the main block 28 from above. The rod Is screwed through a lug 34 which Includes a square shaped projection (not shown) which extends axially Into the slot 24 in the valve plate 20. When the rod is raised or lowered relative to block 28, the proJectlon on the lug 34 bears agalnst the side of the slot to cause pivotal movement of the valve plate with relative sliding movement occurring between the lug and the slot. A pivot pin 35 extends through the block 28 and the centre of the valve plate 20.

In use, the kidney shaped opening 22 Is pivoted In a clockwlse direction until almost all of the opening between the outlet passage 12A and the opening 22 Is obscured. A reduced pressure Is applied to the kidney shaped opening by moving the piston 16 away from the block to cause chocolate to move through the Inlet 10 and passage 10A, Into the kidney shaped opening and through the passage 16A into the space vacated by the piston.

The reduced pressure also acts on the chocolate In the outlet 12 to hold the chocolate therein and prevent It from dripping or flowing out of the outlet 12. The amount or degree of this opening can be varied to take Into account the viscosity of the chocolate to ensure that the opening is Just sufficlent to hold the chocolate at the outlet.

The kidney shaped opening Is then caused to move In an anti-clockwise direction until the passage 10A Is obscured completely from the kidney shaped opening, and the passage 12A is in complete communication with the kidney shaped opening. The required amount of chocolate is then dispensed through the outlet by moving the piston 16 back towards the main block 28. Alternatively, the passage iOA can remain in partial communication at least with the kidney shaped opening when the piston moves back towards the main block such that some or all of the chocolate passes back through the inlet passage. This feature Is of use when a reduced amount of chocolate is required to be dispensed or when no chocolate is required to be dispensed.As the chocolate Is normally supplied from a hopper, the amount oF the passage iOA which is open durlng this part of a cycle can be varled to take Into account different pressures exerted by the head of chocolate in the hopper and the difference In viscosity which the chocolate may have, for Instance on temperature variations.

The valve plate 20 Is then returned in a clockwise direction to its previous position, and the piston may start Its movement away from the block 28 either before or after or during that movement of the valve plate.

The movement of the rod and, alternatively or additionally the piston may be controlled by a computer and may be made In conjunction with a stepped valve In order to ensure the correct weight of discharge and that no drips emanate from the outlet. The rod or piston may be air operated.

Although the invention has been described in relation to a deposit head valve for chocolate it will be appreciated that any fluid may be controlled by the valve.

In an alternative embodiment (not shown), the valve member may be provided on a reciprocally mounted block Instead of being pivotally mounted as illustrated.

Claims

1. A method of controlling or meterlng fluid flow through a valve means vla an inlet to the valve means and an outlet from the valve means with the valve means belng movable relative to the inlet and outlet and being capable of occupying a position In which a passage of the valve means Is in communication with both the in let and outlet comprising selectively applying a reduced or an increased pressure to the valve means by a pressure inducing means with the valve means being In the position In which Its passage is in communication with both the inlet and outlet during at least part of the time when the pressure Inducing means is applying the increased pressure to the valve means and varying the area of communication of the passage with at least one of the inlet or outlet to control or meter the fluid flow.

2. A method as claimed in Claim 1 In which the area of communication of the passage with both the in let and outlet Is varied to control or meter the fluid flow.

3. A method as claimed In Claim 1 or Claim 2 in which, when the pressure Inducing means Is applying an Increased pressure, at least some of the fluid is returned through the inlet.

4. A method as claimed in Claim 3 in which the pressure inducing means does not pass any fluid through the outlet when an increased pressure is applied to the valve means.

5. A method as claimed In Claim 4 in which the outlet is closed when the pressure inducing means applies an increased pressure.

6. A method as claimed In any preceding In which, when an increased pressure is app led by the pressure Inducing means no fluid Is passed back through the in let.

7. A method as claimed In Clalm 6 In which the in let Is closed when an increased pressure Is applied by the pressure inducing means.

8. A method as claimed in any preceding claim In which the outlet Is in communication with the passage when the pressure Inducing means applies a reduced pressure.

9. A method as claimed in Claim 8 in which the area of communication of the outlet with the passage is variable when the pressure inducing means applies a reduced pressure.

10. A method as claimed in any preceding claim in which the valve means is pivoted relative to the Inlet and outlet.

11. A method as claimed in any preceding claim In which the pressure is reduced or Increased by moving a piston.

12. A method as claimed in Claim 11 in which the piston travels a fixed distance in either directlon when an increased or decreased pressure is applled.

13. A method as claimed In any preceding claim In which the fluid is controlled or metered in dependence upon the amount of fluid required to leave the outlet.

14. A method as claimed in any preceding claim in which the fluid is controlled or metered in dependence upon the amblent conditions, Including the pressure of fluid to the in let, the temperature of the fluid or the viscosity of the fluid.

15. A method of controlling fluid flow substantially as herein descrlbed with reference to, and as shown In the accompanying drawings.

16. A control or metering assembly for fluid Including an Inlet and an outlet and valve means movable relative to the inlet and outlet, and pressure Inducing means arranged to co-operate with the valve means, the pressure Inducing means being arranged to provide an increased or a reduced pressure to the valve means, the valve means being capable of occupying a position relative to the Inlet and outlet in which, when the pressure inducing means appi les an increased pressure, the area of communicatlon of a passage of the valve means with at least the Inlet or the outlet Is variable.

17. A control or meterlng assembly as claimed in Claim 16 In which the area between the in let and the passage of the valve means Is adjustable.

18. A control or metering assembly as claimed In Claim 16 or 17 in which the area between the outlet and the passage of the valve means Is adJustable.

19. A control or metering assembly as claimed In any of Claims 16 to 18 in which, In use, when a reduced pressure is applied to the valve means and the passage of the valve means Is In communicatlon with the outlet, fluid at the outlet is capable of being held in place and, when the passage of the valve means Is in communication with the In let and a reduced pressure is applied to the valve means, fluid Is arranged to be drawn In through the in let.

20. A control or metering assembly as claimed in any of Claims 16 to 19 claim In which, In use, when the passage in the valve means Is In communication with the outlet and an Increased pressure is appi led by the pressure inducing means, fluid in the valve means Is discharged through the outlet.

21. A control or metering assembly as claimed in any of Claims 76 to 20 in which the valve means Is pivotally mounted.

22. A control or metering assembly as claimed In any of Claims 16 to 21 in which one side of the passage In the valve means is in communication with the pressure inducing means and the other side of the passage Is capable of communicating with both the inlet and outlet.

23. A control or metering assembly as claimed In any of Claims 16 to 22 in which the pressure Inducing-means includes a reciprocally mounted piston.

24. A control or metering assembly as claimed in any of Claims 16 to 23 in which when the pressure Inducing means exerts an increased pressure on the valve means, at least some of the fluid is capable of being returned through the Inlet.

25. A control or meterlng assembly as claimed In Claim 24 In which, when the pressure Including means exerts an increased pressure, all of the fluid which on the previous reduced pressure has been drawn through the Inlet is capable of being returned through the inlet.

26. A control or metering assembly substantially as hereln described with reference to, and as shown in Figures 1 and 2 of the accompanying drawings.

27. A control or metering assembly as claimed In any of Claims 16 to 26 when used In a method of controlling or mitering fluid as claimed In any of Claims 1 to 15.