WO1996010534A1

WO1996010534A1 - Double diaphragm pump

Info

Publication number: WO1996010534A1
Application number: PCT/GB1995/002332
Authority: WO
Inventors: Paul Anthony England
Original assignee: Rosereed Ltd; Paul Anthony England
Priority date: 1994-09-30
Filing date: 1995-10-02
Publication date: 1996-04-11
Also published as: AU3573595A; GB9419791D0

Abstract

A pump (38) has a product inlet (9) and a product outlet (10). The product can either enter into the chamber (52) or a chamber (53) with reciprocating movement of a shaft (14) causing fluid to be drawn into one of those chambers and pushed out of the other through a common inlet (9) or outlet (10). Pressure is supplied to a remote chamber and selectively to the opposed sides of the chambers having the product in order to drive the shaft (14) in either direction, as required. The shaft (14) includes passages extending along its length to connect the chambers on the opposite sides from those containing the product either to a low pressure vent or to the high pressure source. A valve (29) is slidably mounted on the shaft (14) in order to determine whether a particular chamber is vented or pressurised and movement of the valve is caused by the movement of the shaft (14).

Description

DOUBLE DIAPHRAGM PUMP

The present invention relates to a drinks supply pump and a method of operating a drinks supply pump. The invention is particularly, although not exclusively applicable to pumping products such as syrup and alcoholic beverages.

Traditionally, compressed gas (fluid) driven beverage pumps were used for the pumping of syrup used in carbonated beverages. As is commonly known one of the main problems with the pumping of syrup is the potential for ingestion of compressed gas (fluid) into the product, which can severely affect the taste and quality of the product.

More recently this type of pump has been used for the pumping of various alcoholic beverages of which certain types are sensitive to turbulence and require as much direct flow as possible. Prior art dispensing systems use narrow and tight angled channels for transferring liquid (product) and or compressed gas (fluid) around the pump body. Excessive turbulence is caused by prior art systems that are reliant on transferring liquid (product) around the pump body using these narrow and tight angled channels.

All dispensing systems have to be regularly cleaned. With alcoholic beverages and some soft drinks particularly fresh orange juice, residue remains after dispensing until cleaning takes place. With prior art systems, the tight angled channels can act as catchment areas for this residue and may remain even after cleaning which could lead to potential contamination. In prior art systems, dependent on how many body sections the pump consists of, excessive amounts of sealing washers are required to seal the channels. The flow of liquid (product) is interrupted by the sealing washers and it is at these joints that potential for contamination is also created. There is also potential at all these joints for leakage of both liquid (product) and compressed gas (fluid) .

As previously mentioned, one of the main problems the prior art systems have tried to overcome has been compressed gas (fluid) ingestion into the dispensing system. This can adversely affect the quality and taste of the product. All joints have the potential to leak not only into the product but also externally into the immediate vicinity. The compressed gas (fluid) used to drive this type of pump is mainly C0 and therefore any leakage is a serious problem. Installation of these pumps is generally in small confined areas and CO- build up could result in fatal consequences.

The design of prior art systems has been, in general, over complicated resulting in the use of excessive amounts of components. This in turn, is not only cost ineffective but because of the number of individual components used, the potential for failure due to wear and tear is also excessive.

Prior art systems, because of their complexity have proved uneconomical to re-furbish. The usage for these systems worldwide is immense and not only is it a costly exercise for the customer due to these not being re- furbishable in general, the redundant systems have to be discarded and because the vast majority of material used is plastic and the numbers being discarded are vast, the impact on the environment is enormous.

Whilst the prior art systems have improved greatly, there is still a substantial need in the art for a less complicated, more reliable, unrestricted direct flow system of dispensing which is also environmentally friendly though being refurbishable.

According to one aspect of the present invention a drinks supply pump includes at least one reciprocatable member defining a wall of a chamber that is arranged to contain fluid, the reciprocatable member being arranged to move with connecting means that extend outside of the chamber, the connecting means also being arranged to provide a fluid conduit from the chamber to a location remote from the chamber.

The connecting means may be arranged to extend from the reciprocatable member though the chamber and then to the outside of the chamber. Alternatively the connecting means may extend away from the chamber.

The reciprocatable member may be arranged to define a wall of two chambers, each arranged to contain product and/or fluid/de-pressurised fluid whereby, when the reciprocatable member moves, the volume of one chamber increases and the volume of the other chamber decreases.

The connecting means may extend to a region, remote from the chamber, that is arranged to be provided with a fluid source and a vent. The pump may include a valve to determine whether the fluid source or the vent is placed in communication with the chamber. When the fluid source is placed in communication with the chamber that may serve to drive the reciprocatable member in the first direction. When the vent is in communication with the chamber that may serve to allow the reciprocatable member to move in a second direction, opposite to the first direction, without fluid in the chamber offering any significant resistance to that movement.

The pump may include a further reciprocatable member. The further reciprocatable member may have any of the features of the one reciprocatable member and may also be arranged to move with the connecting means which said connecting means may also be arranged to provide a fluid conduit from the chamber that the further reciprocatable member defines a wall of to a location outside of that chamber.

The valve nay be arranged to place a chamber associated with the further reciprocatable member in communication with the vent for at least part of the time that the chamber associated with the one reciprocatable member is in communication with the fluid source and the valve may be arranged to reverse the fluid/vent connections whereby one of the reciprocatable members is able to drive the other in each direction of movement. Movement of the connecting means may be arranged to alter the connections of the valve.

The valve may include a slidable member on the connection means. The valve may be arranged to be movable between two limit positions. The valve may be caused to move to a different limit position when the connecting means moves in a first or a second, opposite direction. The valve may be caused to move by abutment with a part of the pump that does not move with the reciprocating member. The valve may be located in a chamber and the chamber may be arranged to contain fluid. The valve may be connected to a vent remote from the chamber.

The pump may be provided with two reciprocatable members located side-by-side. Each reciprocatable member may include adjacent chambers that are arranged to contain the product to be pumped. The product to be pumped may be supplied to or, alternatively or additionally, pushed from the chambers via a common inlet or outlet.

According to a further aspect of the present invention a method of operating a drinks supply pump comprises driving a reciprocating member in one direction when a product is being pumped by pushing a driving fluid through a connecting means that is caused to move with the reciprocating member such that the chamber associated with one side of the reciprocating member is caused to increase in volume and a chamber associated with the other side of the reciprocating member is caused to decrease in volume and therefore have product in that chamber pushed therefrom to dispense the product.

The present invention also includes a method of operating a pump when using a drinks supply pump as herein referred to.

According to a further aspect of the present invention, a drinks supply pump comprises a pair of reciprocatable members each comprising a wall within a different product supply chamber, the reciprocatable members being movable to increase the size of the associated chamber during a product charging stroke and movable to decrease the size of the associated chamber during a product discharging stroke, each reciprocatable member, during a discharging stroke being arranged to move in a direction towards the chamber associated with the reciprocatable member.

The reciprocatable members may be constrained to move together and may be connected together. The pump may include a wall that is common to the chambers that are associated with each of the reciprocatable members.

The pump may include a common entry for the product to each chamber and alternatively or additionally the pump may include a common exit for each chamber. Each chamber may have an inlet or, alternatively or additionally an outlet valve associated with the chamber and the inlet or outlet valve may comprise part of the wall of the chamber.

The present invention also includes a pump having any of the features or limitations as herein referred to.

According to a further aspect of the present invention a method of operating a drinks supply pump comprises charging a first chamber with product whilst a second chamber is discharging product and then discharging the first chamber when charging the second chamber, the method being characterised in that the chambers may be located adjacent to each other.

The method may comprise each chamber being supplied through a valve to an outlet or, alternatively or additionally, from an inlet which outlet or inlet are common to both chambers. The valves may be provided in the wall of the chambers. The present invention also includes a method of operating a pump when using a drinks supply pump as herein referred to.

The present invention includes any combination of the herein referred to features or limitations.

The present invention may be carried into practice in various 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 cross sectional view of a drinks supply pump 33 having a valve 29 shown in a first position and with two pistons at one limit of their movement;

Figure 2 is a view similar to figure 1 with the valve in the opposite position and the pistons at their other limit position, and

Figure 3 is a schematic plan cross-sectional view showing the area in the region of the valve and illustrating how the valve can be changed over from one position to the other.

As shown in figure l, the pump 38 includes a product inlet 9 and a product outlet 10. The power that operates the pump 38 comes from fluid that enters via fluid inlet 27 and leaves in a de-pressurised fluid form via de- pressurised fluid outlet 28. The pump 38 can be used for pumping syrup for use in carbonated beverages or in pumping other drinks such as alcoholic beverages.

The pump 38 includes a first cylinder 2 and a second cylinder 3 having, respectively, pistons 15 and 11 with bellow type diaphragms 12 and 13 with the cylinders 2 and 3. The pistons 15 and 11 are connected together by a shaft 14 that extends into a chamber l.

Upon application of pressure to chamber 1 with fluid, the shaft 14 is caused to move to the left in a manner that will be described below. The movement to the left causes both pistons 15 and 11 to move to the left in their respective cylinders 2 and 3. As the piston 15 moves to the left a negative pressure is induced in the chamber 52 of the first cylinder 2 to the right of piston 15. That negative pressure serves to close a one way outlet valve (not shown) in chamber 52 of the first cylinder 2 leading to the product outlet 10 and to open a one way inlet valve (not shown) in the chamber 52 of the first cylinder 2 leading from the product inlet 9 to fill the chamber 52 of the first cylinder 2 to the right of piston 15 with the product. The left hand chamber 51 of the first cylinder 2 contains de-pressurised fluid that is forced through a port 39 in the side of the shaft 14, to the left, along an axial conduit 31 in the shaft 14 and out through a port 40 in the shaft 14. The shaft 14 is of a reduced diameter in the region of the port 40 to allow the de-pressurised fluid to flow around the shaft 14 to a valve outlet 41 and then to the de-pressurised fluid outlet 28 via a flexible tube (not shown) .

Piston 11 is caused to move to the left as a result of fluid in chamber l passing through a port 36 into an axially extending conduit 30 in the shaft 14. This then passes through a port 50 into chamber 54 of the second cylinder 3 to the right hand side of piston 11. It is the pressure in the chamber 54 of the second cylinder 3 that pushes piston 11 and thus moves the shaft 14. As the piston 11 moves to the left the product in chamber 53 of the second cylinder 3 to the left of piston 11 is pushed out through a one way outlet valve 6 in chamber 53 of the second cylinder 3 leading to the product outlet 10. The pressure created serves to close a one way inlet valve 4 in chamber 53 of second cylinder 3 leading from the product inlet 9.

Movement in the opposite direction i.e. to the right, causes both piston 15 and 11 to move to the right in their respective cylinders 2 and 3. As the piston 11 moves to the right a negative pressure is induced in the chamber 53 of the second cylinder 3 to the left of piston 11. That negative pressure serves to close a one way outlet valve 6 in chamber 53 of the second cylinder 3 leading to the product outlet 10 and to open a one way inlet valve 4 in chamber 53 of the second cylinder 3 leading from the product inlet 9 to fill the chamber 53 in the second cylinder 3 to the left of piston 11 with the product. The right hand chamber 54 of the second cylinder 3 contains de-pressurised fluid that is forced through a port 50 in the end of the shaft 14, to the left, along an axial conduit 30 in the shaft 14 and out through a port 36 in the shaft 1. The shaft 14 is of a reduced diameter in the region of port 36 to allow the de-pressurised fluid to flow around the shaft 14 to the valve outlet 41 and then to the de-pressurised fluid outlet 28 via a flexible tube (not shown) .

Accordingly, on each left and right hand movement of the pistons 11 and 15 a metered amount of product is dispensed.

The way in which the valve 29 changes position will be discussed in detail below. However, for the moment the fluid and de-pressurised fluid connections that apply when the pistons 15 and 11 are moving to the right will be described. The valve 29 is movable from a first position, as shown in figure 1, in which it abuts a circlip 43 axially fixed on the shaft 14 to a second position in which the valve 29 abuts a second circlip 42 axially fixed on the shaft 14 as shown in figure 2. In the second position fluid from the chamber 1 passes through the port 40, the axial conduit 31 via port 39 in the shaft 14 into chamber 51 of the first cylinder 2 to the left of piston 15. It is the pressure in this part of the first cylinder 2 that pushes the piston 15 in the first cylinder 2 and thus moves the shaft 14 and the piston 11 in the second cylinder 3 to move to the right. De-pressurised fluid from chamber 54 of the second cylinder 3 to the right of piston 11 is forced through port 50 in the shaft 14 to the left, down the axial conduit 30 in the shaft 14 and out through a port 36 in the shaft 14. The shaft 14 is of a reduced diameter in the region of port 36 to allow the de- pressurised fluid to flow around the shaft 14 to the valve outlet 41 and then to the de-pressurised fluid outlet 28 via a flexible tube (not shown) .

The way in which the valve 29 moves between positions is shown in figures 1 and 2 on the shaft 14, and the way in which the valve 29 is retained in each position will now be described with reference to figure 3.

The valve 29 is axially slidable on the shaft 14 between circlips 42 and 43. A restrictor rod 56 is located through the end of the shaft 14 and into a slot located in both extension arms 44. It is this restrictor rod which serves to limit the movement of both extension arms 44 and so in each extreme position tension is created on the spring wires 46 which in turn urge the valve 29 towards either of the circlips 42 or 43. When viewing figure 3 the valve extension arms 44 are shown in their extreme right position. In this position the spring wires 46 act to urge the valve 29 towards the circlip 42 and hold the valve there. As the shaft 14 moves to the right, the extension arm legs 47 abut the wall 48 that defines the space between the chamber 1 and the first cylinder 2. Because the extension arms 44 are slidably mounted on the valve 29 the momentum of the shaft 14 allows the shaft 14 to continue moving to the right. Accordingly, some relative axial movement in the extension arms 44 towards the circlip 42 occurs. Resilient spring wires 46 are pivotally connected to the extension arms 44 and the valve 29. After the spring wires 46 have gone over centre, which occurs when the connection points on the extension arms 44 are aligned in the same radial plane as the connection points on the valve 29, the spring wires 46 act to urge the extension arms 44 towards the circlip 42 and their extreme left position and the valve 29 is urged towards the circlip 43.

When the shaft 14 is travelling to the left, when viewed in the drawings, extension arm legs 57 of the valve 29 abut the wall 45 of the chamber 1. Because the extension arms 44 are slidably mounted on the valve 29 the momentum of the shaft 14 allows the shaft 14 to continue moving to the left. Accordingly, some relative axial movement in the extension arms 44 towards the circlip 43 occurs. Resilient spring wires 46 are pivotally connected to the extension arms 44 and the valve 29. After the spring wires 46 have gone over centre, which occurs when the connection points on the extensions arms 44 are aligned in the same radial plane as the connection points on the valve 29, the spring wires 46 act to urge the valve 29 towards the circlip 43 and their extreme right position and the valve 29 is urged towards the circlip 43. When the fluid pressure is eased, the shaft 14 will move to its extreme right or left hand position and the valve 9 will also be moved over such that the pump 38 is ready to operate again when pressure is re-applied.

When servicing of the valve 29 is required, dismantling of the first cylinder 2, second cylinder 3 and cap 22 is not necessary. The cap 55 having the end wall 45 that defines all but the wall 48 of the chamber 1 is unbolted and removed from the remainder of the pump 38 to leave the valve 29 exposed. It can be seen that the valve 29 can be replaced by removing the restrictor rod 56 and circlip 42 and sliding the valve 29 off the shaft 14 without disturbing either the first cylinder 2, second cylinder 3 or cap 22.

It can be seen that the first cylinder 2 only has a single seal being a bellow type diaphragm 12. This for providing the movement of the piston 15 and for exhausting or powering the side of the piston 15. Furthermore, the second cylinder 3 only has one such seal being a bellow type diaphragm 13. Accordingly, the number of seals and consequently the risk of breakdown is reduced significantly from those that are required with pumps having separate shafts, fluid de-pressurised fluid and product connections.

Cleansing of the pump is relatively easy as the product is fed straight into and out of the first cylinder 2 and the second cylinder 3 from a common product inlet 9 and product outlet 10. Accordingly the pump 38 does not have the tortuous passageways connecting spaced cylinders to the product. As previously mentioned, the main driving force currently used for this type of pump is carbon dioxide. As the carbon dioxide is being supplied under pressure and as the carbon dioxide enters and forces a piston and remains under pressure it is in liquid/fluid form. When, however, the vent of the valve is opened and the pressure is reduced, the liquid/fluid carbon dioxide changes states to de-pressurised gaseous carbon dioxide.

1. pressurised chamber

2. first piston cylinder

3. second piston cylinder

4. one way inlet valve 6. one way outlet valve

9. product inlet

10. product outlet

11. piston

12. bellow type diaphragm 13. bellow type diaphragm

14. shaft

15. piston 22. cap

27. fluid inlet 28. de-pressurised fluid outlet

29. valve

30. axial conduit

31. axial conduit 36. port 38. drinks supply pump

39. port

40. port

41. valve outlet

42. circlip 43. circlip

44. extension arms

45. chamber wall

46. spring wires

47. extension arm legs 48. wall

50. port

51. left hand chamber of piston 15.

52. right hand chamber of piston 15

53. left hand chamber of piston 11 54. right hand chamber of piston 11

55. cap

56. restrictor rod

57. extension arm legs

Claims

1. A drinks supply pump including at least one reciprocatable member defining a wall of a chamber that is arranged to contain fluid, the reciprocatable member being arranged to move with connecting means that extend outside of the chamber, the connecting means also being arranged to provide a fluid conduit from the chamber to a location remote from the chamber.

2. A pump as claimed in Claim l in which the connecting means are arranged to extend from the reciprocatable member through the chamber and then to the outside of the chamber.

3. A pump as claimed in any preceding claim in which the connecting means extend away from the chamber.

4. A pump as claimed in any preceding claim in which the reciprocatable member defines a wall of two chambers, whereby, when the reciprocatable member moves, the volume of one chamber increases and the volume of the other chamber decreases.

5. A pump as claimed in any preceding claim in which the connecting means extend to a region remote from the chamber that is arranged to be provided with the fluid source and a vent.

6. A pump as claimed in Claim 5 including a valve to determine whether the fluid source or the vent is placed in communication with the chamber.

7. A pump as claimed in either of Claims 5 or 6 in which, when the fluid source is placed in communication with the chamber, that may serve to drive the reciprocatable member in a first direction.

8. A pump as claimed in Claim 7 in which when the vent is in communication with the chamber that may serve to allow the reciprocatable member to move in a second direction, opposite to the first direction, without fluid in the chamber offering any significant resistance to that movement.

9. A pump as claimed in any preceding claim including a further reciprocatable member.

10. A pump as claimed in Claim 9 in which the further reciprocatable member has all of the features of the first mentioned reciprocatable member.

11. A pump as claimed in Claim 9 or 10 in which the further reciprocatable member is also arranged to move with the connecting means.

12. A pump as claimed in Claim 11 in which the connecting means also provides a fluid conduit from the chamber that the further reciprocatable member defines a wall of to a location outside of that chamber.

13. A pump as claimed in any of Claims 9 to 12 in which a valve is arranged to place a chamber associated with the further reciprocatable member in communication with the vent for at least part of the time that the chamber associated with the first mentioned reciprocatable member is in communication with the fluid source.

14. A pump as claimed in Claim 13 in which the valve is arranged to reverse the fluid/vent connections.

15. A pump as claimed in Claim 14 in which movement of the connecting means is arranged to alter the connections of the valve.

16. A pump as claimed in any of Claims 13 to 15 in which the valve includes a slidable member on the connection means.

17. A pump as claimed in Claim 16 in which the valve is arranged to move between two limit positions.

18. A pump as claimed in Claim 17 in which the valve is caused to move to a different limit position when the connecting means moves in a first or a second, opposed direction.

19. A pump as claimed in any of Claims 16 to 18 in which the valve is arranged to be caused to move by abutment of a part associated with the valve that is able to move by a restricted amount only with respect to the reciprocatable member with another part of the pump.

20. A pump as claimed in any of Claims 13 to 19 in which the valve is located in a chamber 21.

21. A pump as claimed in Claim 20 in which the chamber is arranged to contain fluid.

22. A pump as claimed in Claim 21 in which the valve is connected to a vent remote from the chamber.

23. A pump as claimed in any preceding claim provided with two reciprocatable members located side-by-side.

24. A pump as claimed in Claim 23 in which each reciprocatable member includes adjacent chambers that are arranged to contain the product to be pumped.

25. A pump as claimed in Claim 24 in which the product to be pumped is arranged to be supplied to the chambers via a common inlet.

26. A pump as claimed in Claim 14 or 15 in which the product is arranged to be pushed from the chambers via a common outlet.

27. A drinks supply pump comprising a pair of reciprocatable members each comprising a wall within a different product supply chamber, the reciprocatable members being movable to increase the size of the associated chamber during a product charging stroke and movable to decrease the size of the associated chamber during a product discharging stroke, each reciprocatable member during a discharging stroke being arranged to move in a direction towards the chamber associated with the other reciprocatable member.

28. A drinks supply pump substantially as herein described with reference to, and as shown in any of the accompanying drawings.

29. A method of operating a drinks supply pump comprising driving a reciprocating member in one direction when a product is being pumped by pushing a driving fluid through a connecting means that is caused to move with the reciprocating member such that the chamber associated with the one side of the reciprocating member is caused to increase in volume and a chamber associated with the other side of the reciprocating member is caused to decrease in volume and therefore have product in that chamber pushed therefrom to dispense the product.

30. A method of operating a drinks supply pump comprising charging a first chamber with product whilst a second chamber is discharging product and then discharging the first chamber when charging the second chamber, the method being characterised in that the chambers are located adjacent to each other.

31. A method of operating a drinks supply pump substantially as herein referred to with reference to and as shown in any of the accompanying drawings.

32. A method of operating a drinks supply pump as claimed in any of Claims 29 to 31 when using a drinks supply pump as claimed in any of Claims 1 to 28.