GB2192673A - Improved diaphragm milk pump - Google Patents

Abstract

A diaphragm pump (10) for milk in which the diaphragm (34) operates in a chamber (32) attached to an intermediate chamber (30) which is connected to a source of milk. The diaphragm (34) does not transverse the intermediate chamber (30) and enables unobstructed free loading of the intermediate chamber with milk. This assists in loading the pump. Various forms of inlet and outlet valve are described. In the embodiment shown the inlet comprises a flap 39, lifted by vacuum applied to chamber 50 above diaphragm 48 simultaneously with the vacuum applied to chamber 35 beneath diaphragm 34, thus synchronising the supply of fluid with the demand for it. Other forms include a gate valve lifted by a piston which is itself raised by vacuum and linked poppet inlet and outlet valves driven by a diaphragm similar to that of Fig. 2. <IMAGE>

Description

SPECIFICATION Improved diaphragm milk pump The present invention relates to pumping apparatus for liquids, particularly milk in a milking machine system.

The common form of milk pumps in use are the centrifugal and especially the motor driven "push-pull" diaphragm pumps known in the Industry for many years. Both these pumps cause serious agitation and aeration of milk; this effect being well illustrated by the abundance of froth produced. This turbulent aeration of milk is conducive to fracture of the membrane surrounding the fat globules causing a chemical action known as lypolysis. Lypolysis is responsible for unpleasant and rancid flavours in both milk and manufactured milk products.

Diaphragm pumps of various design have previously been produced to obviate this effect and typical of prior art specifications disclosing pumps of this type are Australian Patent Specifications Nos. 217929, 517942 and 459745. These pumps generally comprise a diaphragm chamber traversed by a flexible diaphragm, the diaphragm being moved across the chamber by imposed pulses of pressure air interposed with negative air or vacuum conditions. The pumps normally comprise a form of one way inlet valve and a one way outlet valve and are fed by gravity from a milk receival vessel. While these pumps have been used and have operated relatively satisfactorily they do suffer from a number of disadvantages which affect both efficiency and capacity and make them totally inadequte in performance to handle the increased milk flows of the larger herds now commonly pertaining in the Industry.

Firstly, there is no intermediate fluid available between the milk receival vessel and the pump chambers with which to facilitate fast loading of the pump with negligible obstruction. The pump chambers are immediately connected to the milk receival vessels and all milk must pass directly over the inlet valves, before percolating through a series of holes which are so placed across the inlet orifice to contain the pump diaphragm during the discharge phase. This obstructed path affects capacity by increasing loading time and thus reducing the otherwise obtainable strokes per minute. It can be understood that primarily, capacity is entirely related to the time cycle in which the pump chamber can be fully charged and discharged.Also full loading of these pumps does not take place until sufficient "head" pertains in the milk receival vessel to supply the weight or pressure to both overcome the obstruction to flow as described and to fully depress the diaphragm to obtain full loading.

Secondly, closing of the inlet valves depends on the pressure generated by the upward movement of the diaphragm during the delivery stroke. The higher the "head" in the receival vessel the greater the force preventing the valves closing and the greater the volume of fluid passing from the pump back into the receival vessel thus drastically reducing the amount delivered.

The object of the present invention is to provide improved pumping apparatus of the above type which avoids the known disadvantages and supplies an effective and efficient pumping unit.

According to the present invention there is provided pumping apparatus for milk or other liquids comprising a diaphragm type pump including a pumping diaphragm operating in a pumping chamber having an attached intermediate chamber in fluid communication with said pumping chamber arranged such that the pumping diaphragm does not traverse said intermediate chamber, said intermediate chamber being adapted for connection to a source of said milk or other liquids enabling unobstructed free loading of said intermediate chamber wih said milk or other liquids. Preferably the intermediate chamber may have a volume greater than a swept volume of said pumping diaphragm in said pumping chamber.

Conveniently the intermediate chamber has a non-return inlet valve and a non-return outlet valve with the fluid communication between said intermediate chamber and said pumping chamber being located generally between the inlet and the outlet valves. The non-return inlet valve is advantageously a pivoted flap valve adapted to pivot inwardly of said intermediate chamber when moving towards an open condition. The flap valve may be arranged to cooperate with a valve seat inclined with respect to the milk or other liquids flow direction therethrough. In another embodiment the non-return inlet valve may comprise a sliding gate valve.

In accordance with a particularly preferred embodiment the non-return inlet valve is positively closed when said pumping diaphragm performs a pumping stroke in said pumping chamber. Conveniently alternate pulses of pressurized air and vacuum conditions are applied to an operating mechanism for said inlet valve, said operating mechanism acting to positively close the inlet valve upon a said pressurized air pulse being applied thereto, the same pressurized air pulse being applied to said pumping diaphragm to effect said pumping stroke. The alternate pulses of pressurized air and vacuum conditions may be supplied fom a pulsator unit associated with a milking machine system.

The invention will be better understood from the following description of preferred embodiments given in relation to the accompanying drawings, in which: Figure 1 is a schematic flow diagram of a milking machine system incorporating a pumping unit according to the present invention; Figure 2 is a cross sectional view of pumping apparatus according to a first preferred embodiment of the present invention; Figure 3 is a partial cross sectional view similar to figure 2 sharing alternative features of a second embodiment; Figure 4 is a cross sectional view of pumping apparatus according to a third simplified preferred embodiment; and Figure 5 is a cross sectional view of pumping apparatus according to a fourth preferred embodiment.

Referring first to figure 1 there is shown pumping apparatus 10 in accordance with the present invention in a milking machine system.

A milk receiver tank 11 receives milk via line 12 from the milking units not illustrated. Milk flows by gravity via line 13 to the pumping unit 10 and line 14 delivers the milk to the desired end destination not illustrated.

A compressor (not shown) supplies pressurized air to a reservoir 15 via line 29 which supplies pressurized air via the line 16 to the base of the pump driving pulsator 18 which is illustrated schematically in Figure 1. The pump pulsator in turn delivers alternate vacuum and compressed air pulses via the lines 23, 24 and 25 respectively to a pump operating mechanism 26 and to a pump chamber 27 of the pumping apparatus 10. The pulsator unit may be of the type disclosed in U.S. Patent No. 4,513,766 but other types of pulsator units could equally be employed. A vacuum tank 19 evacuated via line 20 by means not illustrated is provided to establish a permanent source of vacuum conditions. The line 21 provides a permanent vacuum condition to the pulsator 18 vacuum to the milk receival vessel 11 being connected via the line 28.

Referring now to Figure 2 there is shown a first preferred embodiment of pumping apparatus 10 according to the present invention. The pumping apparatus comprises a first chamber 30 adapted to form part of a liquid transfer conduit, said first chamber 30 being connected to a source of liquid supply via the pipe 13 and also via a connection 31 to a second (or pumping) chamber 32 housing a concave shaped flexible diaphragm 34 which divides said second chamber 32 into two compartments. A first one of said compartments 33 being on communication with said first chamber 30 via the connection 31 and a second one of said compartments 35 being connected to a source of alternate vacuum/air pulses via the connection 36 and line 25.The pumpinq apparatus further includes an inlet valve comprising an inclined valve seat 37; defining a central flow passage 38 and a flap element 39 which is relatively heavy and hinged at 40 above the flow passage 38 such that it may be swung away or towards the valve seat 37 controlling liquid flow into the chamber 30 but preventing flow back to the source of supply 11.

As distinct from a vertical seat the inclined seat offers less restriction to flow by increasing the apparent seat size. Also the inherent reduction in valve movement in opening and closing, speeds pumping action thus giving increased performance.

At the outlet end of chamber 30 there is arranged a guided non-return valve assembly having a body 41, a removable top 42, an outlet 43 leading to pipe 14 and a storage tank or other equipment (not shown) and giving access to a guided outlet valve 44, its seat 45 and valve guide 46. A suitable clamping arrangement 47 is used to seal the removable top 42 to the body 41.

Mounted externally on the chamber 30 and in a convenient position relative to the flap valve 39 is the valve operating mechanism 26.

The valve operating mechanism may be a piston operating in a cylinder or preferably comprise a diaphragm 48 attached to the piston 52 and clamped at a convenient position in the chamber formed within the body 50. The upper surface of the diaphragm 48 is exposed to alternate vac/air pulses via line 24 and the base 49 of the body 50 has a series of holes 51 giving access to atmosphere below the diaphragm 48. A piston element 52 is operably engaged by the diaphragm 48 and a connecting rod 53 is moved by the piston element 52 in response to movement of the diaphragh 48. The rod 53 passes through a suitable guide 54 into the chamber 30 and is connected via a hinged joint 55 to the flap valve 39. Access to the flap valve 39 and its attachments is made by releasing the sealing clamp 56 and removing the liquid supply pipe 13.

The alternate vac/air pulses available at the connections 36 and 24 are synchronised in action i.e. when a vacuum pulse is operative to the top of the diaphragm 48 through the connection 24 a vacuum pulse also pertains to the compartment 35 below the diaphragm 34 through the connection 36 and vice versa.

When vacuum pertains to the top of the diaphragm 48 through the connection 24 there is caused a negative pressure above the piston diaphragm 48. Atmospheric air now entering through the holes 51 in the base 49 below the diaphragm 48 immediately forces the diaphragm upwards to the top of its stroke and at the same time lifting the flap valve 39 via the attached linkage 52, 43 and 55 to the fully open position. Liquid thus flows freely via the liquid supply pipe 13 into the chamber 30 and through the connection 31 into the compartment 33 above the concave diaphragm 34. Synchronously vacuum pertains to the compartment 35 below the diaphragm 34 removing air and allowing the weight of the liquid entering the compartment 33 via the connection 31 to instantly depress the con cave diaphragm 34 to the full extent of the compartment 35 thus fully charging the chamber 32.At the conclusion of the vacuum phase air now pertains at the connections 24 and 36. Air entering via the connection 24 to the top of the diaphragm 48 rapidly forces the piston element 52 downwards and via the linkage 53, 55 immediately closes the flap valve 39 on to its seat 37 thus stopping the flow of liquid into the chamber 30. At the same time air entering via the connection 36, simultaneously forces the diaphragm 34 upwards completely expelling the fluid contained in the pump chamber 32 into the chamber 30 via the connection 31. This fluid in turn displaces the residual fluid in the chamber 30 forcing it upwards unseating the non-return valve 44 and allowing the full equivalent contents of the pump chamber 32 to be passed to a storage tank or other equipment via the connection 43.When liquid supply to the pump is low no pumping action takes place, the liquid merely being passed between the chamber 32 and the chamber 30.

The liquid being under continuous vacuum from the source of supply 11, this action ensures the complete freedom from aeration of all milk pumped. On the conclusion of the complete discharge phase weight of fluid above the non-return valve 44 assists it to return promptly to its seat 45.

It can be noted that at each given vacuum phase the loading of the pump chamber 32 is accelerated by the fluid contained in the chamber 30. This fluid is fully sustained by the inflow through the pipe 13.

The centre of the flexible concave diaphragm 34 has a reinforced or thickened area 56 corresponding to slightly more than the internal area of the connection 31 in order to prevent bulging into the connection and damage to the diaphragm during the discharge phase of the pump.

Figure 3 of the accompanying drawings illustrates an arrangement incorporating alternate features to those shown in Figure 2. Like features in Figures 2 and 3 have been given the same reference numerals. In this embodiment the inclined inlet valve seat of Figure 2 has been replaced with a perpendicular (relative to the liquid flow direction) seat 57 which is opened or closed by a sliding gate valve member 58 moving ih a restraining guide 59.

The operating mechanism 26 includes a piston 52 with a sliding seal 60 engaging the cylindrical wall 61 of the operating mechanism. As with the embodiment of Figure 2, when vacuum conditions are applied above the piston 52 via the connection 24, atmospheric pressure through holes 51 move the piston upwardly to open the inlet valve 58. When pressurized air conditions apply above the piston 52 with atmospheric air pressure still existing on its lower surface, the piston moves down to positively close the inlet valve. It will of course be appreciated that an operating mechanism as shown in Figure 3 might also be used in the embodiment of Figure 2.

Reference will now be made to the embodiment shown in Figure 4 which does not use an arrangement for positively closing (or opening) the non-return inlet valve. In this embodiment the intake pipe 13 leading from the tank 11 directs liquid flow into the intermediate chamber 30. The outlet pipe 14, similar to other embodiments, directs liquid flow away from the pumping apparatus 10.

The chamber 30 is connected between the intake and the delivery pipes 13 and 14. A non-return inlet valve 62 and a non-return outlet valve 63 are located at either end of the first chamber 30 and seal means 63 on their outer surfaces co-operate with angled flanges of pipes 13 and 14 and the chamber 30 to provide a seal therebetween when clamped by a split clamping ring 56 of known construction.

A passage 31 is provided leading from the first chamber 30 intermediate its ends to a diaphragm chamber 32. A flexible diaphragm 64 divides the chamber 32 into a first compartment 33 communicating with the first chamber 30 via passage 31 and a second compartment 35 acting as an actuating chamber communicating with a source of alternate aiqvacuum pulses via connection 36.

The operation of the diaphragm 64 within the diaphragm chamber 32 is essentially conventional in nature.

The construction of the inlet and outlet valves 62 and 63 are essentially similar. Each valve comprises an inclined valve seat 65 defining a central flow passage 66 and a flap element 67 which is relatively heavy and hinged at 68 above the flow passage 56 such that it may be swung away from or towards the inclined valve seat 65. It is believed that the inclination of the valve seat in the manner illustrated assists in preventing valve bound or chatter and therefore assists in the positive operation of the pumping arrangement described.

Operation of the arrangement shown in Figure 4 is essentially similar to that of the earlier described embodiments. Milk or other liquid readily flows into the chamber 30 when the diaphragm 64 is flexed downwardly under action of vacuum from the connection 36. In this matter the liquid readily fills substantially all of the chamber 32 and most of the chamber 30. When compressed air is applied at connection 36 to the diaphragm 64 the diaphragm performs a pumping stroke across the chamber 32 forcing liquid forwardly through the outlet valve 63 and the liquid at the same time forces the flap valve 67 of inlet valve 62 to a closed position. Because there is substantially more liquid in the chambers 30, 32 than can be moved by one pumping stroke of the diaphragm 64, there is always sufficient liquid to immediately fill the pumping chamber 33 ready for the next pumping stroke.

Referring now to Figure 5, there is illustrated a fourth preferred embodiment where like features have been identified by the same numerals with regard to previously described embodiments. The pumping apparatus 10 includes a first chamber 30 connected via the pipe 13 to a source of liquid supply and also via a connection 31 to a second (pumping) chamber 32. As with previous embodiments a concave shaped flexible diaphragm 34 divides the chamber 32 into two compartments 33, 35. The compartment 35 is connected via connection 36 and line 25 to a source of alternate vacuum/compressed air pulses. In this embodiment an inlet valve 70 comprising a poppit styled valve member 71 with a valve stem 72 guided for vertical reciprocation to open and close an inlet flow opening 73.An outlet valve 74 comprises a poppit styled valve member 75 with a valve stem 76 provided for vertical reciprocation to open and close an outlet flow opening 77. An extension 78 of the valve stem 72 is connected via a link member 79 to an extension 80 of the valve stem 76. In this mannner when the valve member 71 is open as illustrated, the valve member 75 is closed and vice versa.

The inlet and outlet valves 70, 74 are actuated by a valve operating mechanism 26. The operating mechanism 26 may be in accordance with any of the preceding embodiments but preferably 48 attached to a piston 52 and clamped at a convenient position in the chamber within the body 50. The lower surface of the diaphragm 48 is exposed to alternate vacuum/compressed air pulses via line 24 and the upper surface of the diaphragm 48 is subjected to atmospheric pressure via holes 51 in an upper wall of the body 50. When vacuum pertains to the chamber 35 vacuum also exists within the body 50 below the diaphragm 48. As a result, a piston rod 81 connecting piston 52 to the link member 79 thereby opening inlet valve 70 and closing valve 74.

When compressed air is directed into chamber 35, the same air under pressure is directed below the diaphragm 48 effecting closure of the inlet valve 70 and opening of the outlet valve 74. Otherwise operation of this embodiment is generally similar to previously described embodiments.

Claims (11)

1. -1. Pumping apparatus for milk or other liquids comprising a diaphragm type pump including a pumping diaphragm operating in a pumping chamber having an attached intermediate chamber in fluid communication with said pumping chamber arranged such that the pumping diaphragm does not traverse said intermediate chamber, said intermediate chamber being adapted for connection to a source of said milk or other liquids enabling unobstructed free loading of said intermediate chamber with said milk or other liquids.
2. 2. Pumping apparatus according to claim 1 wherein the intermediate chamber has a nonreturn inlet valve and a non-return outlet valve.
3. 3. Pumping apparatus according to claim 2 wherein -at least said inlet valve comprises a pivoted flap valve adapted to pivot inwardly of said intermediate when moving towards an open condition.
4. 4. Pumping apparatus according to claim 3 wherein said flap valve is arranged to co-operate with a valve seat inclined with respect to the milk or other liquids flow direction therethrough.
5. 5. Pumping apparatus according to claim 2 wherein said inlet valve comprises a sliding gate valve.
6. 6. Pumping apparatus according to anyone of claims 2 to 5 wherein said non return inlet valve is positively closed when said pumping diaphragm performs a pumping stroke in said pumping chamber.
7. 7. Pumping apparatus according to claim 6 wherein alternate pulses of pressurized air and vacuum conditions are applied to an operating mechanism for said inlet valve, said operating mechanism acting to positively close the inlet valve upon a said pressurized air pulse being applied thereto, the same pressurized air pulse being applied to said pumping diaphragm to effect said pumping stroke.
8. 8. Pumping apparatus according to claim 7 wherein the alternate pulses of pressurized air and vacuum conditions are supplied from a pulsator unit associated with a milking machine system.
9. 9. Pumping apparatus according to anyone of claims 1 to 8 wherein said pumping diaphagm comprises a flexible concave diaphragm with a central reinforced zone adapted to engage an outlet from said pumping chamber.
10. 10. Pumping apparatus according to claim 1 including an inlet valve controlling flow of liquid to said intermediate chamber and an outlet valve controlling flow of liquid from said intermediate chamber, said inlet valve and said outlet valve being connected whereby when said outlet valve is open said inlet valve is closed and vice versa, and actuating means provided to positively move said inlet and said outlet valves in sequence with movement of said pumping diaphragm.
11. 11. Pumping apparatus according to claim 1, substantially as described with reference to any one of Figures 2 to 5 of the accompanying drawings.