GB2035030A - Milking machine pulsators - Google Patents

Abstract

An alternating cycle diaphragm pulsator for a milking machine, comprises wall means defining a housing (1), a first diaphragm (6) coupled to a first valve member (9) to form a first diaphragm-valve unit, a second diaphragm (7) coupled to a second valve member (10) to form a second diaphragm-valve unit, and a third diaphragm (8) coupled to the second diaphragm-valve unit to define a first chamber (19) with the second diaphragm-valve unit and a stabilizing chamber (20) with a first portion of the wall means. The stabilizing chamber 20 is in communication through duct means (23) with a second chamber (14) and the duct means (23) communicates through throttle means (25) with a working chamber (16). In the illustrated embodiment connections to vacuum are made at 27, 28 and air inlets are provided at 21, 29. Teat-cup pairs are connected at 22 and 26. <IMAGE>

Description

SPECIFICATION Alternating cycle diaphragm pulsator The present invention relates to an alternating cycle diaphragm pulsator for a milking ma chine.

Different control mechanisms for milking machines are known for the attainment of phase displacement, i.e. prolongation of the suction phase by comparison with the relief phase. Valves controlled by cams and levers are very expensive. Slide controls require great preceision in their manufacture, since they otherwise wedge or, due to high static friction, do not maintain the cyclic rate after a certain running time. They are particularly sensitive when milk penetrates into these through damaged teat rubbers. They operate mostly with hydraulic damping means for delaying the point at which switching-over occurs.

Some known unidirectional and alternating cycle diaphragm pulsators are provided with coupled valves which make phase displacement possible. Soviet originator's certificate 1 74 891 describes such a pulsator which comprises two diaphragms with plate valves connected thereto. The phase displacement of the second valve takes place through additional throttling of air suction away from a working chamber through a ball valve. This valve and the freed cross-section determine the phase relationship of the second valve.

The phase relationship of the first valve is determined by the effective surfaces of the diaphragms and the plate valve inclusive of the weight of the plate valve. The air supply to and suction out of the operating chamber above the diaphragms takes place through a variable throttle, the opening cross-section of which determines the cyclic rate.

A disdavantage of this pulsator is that the phase relationship of the second valve agrees only at a certain cyclic rate with the phase relationship of the first valve. This is because the delay of the closure of the second valve is constant, while the cyclic rate varies through resetting of the throttle device on both valves.

The consequence of this is that the relief phase at higher cyclic rates is shorter in relation to the suction phase in the second valve and longer at lower cyclic rates. As a result of pollution, the throttle cross-section in the second valve can vary, i.e. the throughflow is reduced so that with a correctly set cyclic rate, a spontaneous change of the phase relationship in the second valve occurs through a change in the delay. This irregularity cannot, in practice, be detected without measuring equipment and thereby influences the milking process. The cleaning of the throttle valve and the correct setting can be performed only by specialists.

According to the present invention there is provided an alternating cycle diaphragm pulsator for a milking machine, comprising wall means defining a housing, a first diaphragm coupled to a first valve member to form a first diaphragm-valve unit, a second diaphragm coupled to a second valve member to form a second diaphragm-valve unit, and a third diaphragm coupled to the second diaphragmvalve unit to define a first chamber with the second diaphragm-valve unit and a stabilising chamber with a first portion of the wall means, the stabilising chamber being in communication through duct means with a second chamber formed by the first diaphragm-valve unit and the duct means communicating through throttle means with a working chamber defined by surfaces of the first and the second diaphragm and a second portion of the wall means.

The two diaphragm-valve-units can be arranged in parallel or in series. The stabilizing chamber can for example adjoin the working chamber or be disposed opposite to it. Consequently, the working chamber in the case of the one diaphragm-valve unit can for example be formed either by the two diaphragms or by the diaphragm and the housing. Likewise, the valve member of this unit can for example be arranged between the two diaphragms or oppositely.

An exchange of fresh air and vacuum connections is also possible with a constructional adaptation of the effective surfaces.

The manner of effect of a pulsator with the combined diaphragm-valve-diaphragm switching unit, in which the valve member is disposed with valve seats therefor between the two diaphragms, can be the following: Through application of under-pressure, the diaphragm forming the working chamber move outwardly and in the simple diaphragm valve coupling connect the vacuum supply with a milk beaker connection and thereby through a channel with the stablizing chamber and through a throttle with the working chamber. The combined valve unit connects the fresh air supply with another milk beaker connection.The air is slowly sucked out of the working chamber through the throttle until the switching point is reached, at which the valve member in the case of the combined valve unit switches over in consequence of the reducing counterforce and in that case connects the chamber with the constant vacuum with the milk beaker connection. In this instant, both milk beaker connections are under vacuum. The pressure in the working chamber is further reduced through the throttle until the counter-pressure has fallen away so far that also the simple diaphragm valve unit switches over and connects this milk beaker connection with the atmosphere. Thereby, fresh air flows through the connecting channel into the stabilizing chamber and the pressure in the working chamber increases slowly through the air supplied throttled.Since the full atmospheric air pressure is present in the stabilizing chamber, this switching unit is sta ble and thereby independent of the pressure rise in the working chamber. With a further rise of pressure in the working chamber, the counter-force of the simple diaphragm valve unit is overcome and the valve member switches over. Thus, this milk beaker connection is again under vacuum and sucks away the air out of the stabilizing chamber unthrot tled through the channel so that the counter force of the stabilizing chamber is cancelled and the combined diaphragm-valve unit switches over. The device is thus again in its initial setting. A new cycle begins with the throttled evacuation of the working chamber.

In an embodiment in which the valve member of the combined valve unit sits by a valve seat thereof between diaphragm and housing, the manner of operation may be as follows: On application of the underpressure, the fresh air supply of both valves is closed and all milk beakers and the stabilizing chamber are under vacuum. The pressure in the working chamber is slowing reduced through the throttle. After overcoming the counter-force at the combined diaphragm-diaphragm valve unit, this switches over, i.e. atmospheric air is at one milk beaker pair. The pressure in the working chamber is further reduced through the throttle until the counter-force in the case of the simple diaphragm-valve unit is overcome so that also this valve switches over.

Atmospheric air pressure is briefly at both outlets to the milk beakers. The air, which has flowed into the stabilizing chamber through the connecting channel, effects an immediate switching-over of the combined switching unit to vacuum in the associated milk beaker pair.

A slow pressure rise in the working chamber takes place through the connecting channel and the throttle. After overcoming the counterforce, the simple switching unit switches over, both outlets to the milk beakers are under vacuum and the new cycle begins.

The advantage of diaphragm pulsators compared with slide-controlled or piston-controlled pulsator of equal value are short switching paths, small moved masses, frictionless switching, simple manufacture and assembly, cheap materials, little or no mechanical processing of the parts formed without cutting with attainment of a good operating mode and little liability to trouble.

Embodiments of the present invention will be more particularly described by way of example and with reference to the accompanying drawings in which: Figure 1 shows an embodiment of the present invention in an initial setting, Figure 2 shows the embodiment after the first switching-over, Figure 3 shows the embodiment after the second switching-over, Figure 4 shows the embodiment in the last switch setting of one cycle, Figure 5 shows a diagram of the pressure variation in the working chamber, for example for a duty cycle of 2::1, Figure 6 shows a second embodiment of the present invention with modified air and vacuum connections, Figure 7 shows a third embodiment of the present invention, Figure 8 shows the third embodiment after the first switching-over, Figure 9 shows the third embodiment after the second switching-over, Figure 10 shows the third embodiment in the last switch setting of one cycle, and Figure 11 shows a fourth embodiment of the present invention with modified vacuum and air connections.

An alternating cycle pulsator shown in Figs.

1 to 4 comprises a housing 1, in which valve seats 2, 3, 4 and 5 are accommodated.

Diaphragms 6, 7 and 8 are firmly clamped and valve members 9 and 10 are displaceably arranged in the housing 1. The diaphragm 6 is connected with the valve member 9 through a linkage 11. The diaphragms 7 and 8 are connected through linkages 1 2 and 13 with the valve member 10. A chamber 14 for the alternating pressure is disposed between the housing 1 and the valve seat 2. The chamber 1 5 for the constant vacuum is disposed between valve seat 2 and the diaphragm 6. A working chamber 1 6 is disposed between the diaphragms 6 and 7. A chamber 1 7 for fresh air is disposed between the diaphragm 7 and the valve seat 5. A chamber 1 8 for alternating pressure is disposed between the valve seats 4 and 5.A chamber 19 for constant vacuum is disposed between the valve seat 4 and the diaphragm 8. A chamber 20 for stabilization is disposed between the diaphragm 8 and the housing 1. The valve seat 3 is formed by the periphery of a bore 21 in the housing 1. Connections 27 and 28 for the constant vacuum communicate with the chambers 1 5 and 19. The fresh air supply takes place through the bore 21 and a stub 29 ta the chamber 17. The chamber 14 is connected through a connection 22 with a milk beaker pair and through a duct 23 with the chamber 20. A duct 24, into which a throttle 25 is connected and which opens into the working chamber 16, branches off from the duct 23. A connection 26 from the other milk beaker pair opens into the chamber 18.

As Fig. 1 shows, underpressure prevails through the opened valve 2 in the chambers 1 5 and 14 and propagates through the connection 22, the channel 23 into the chamber 20 and also through a branch to one milk beaker pair. Furthermore, the pressure in the working chamber 16 is reduced through the duct 24 and the throttle 25. Fresh air flows through the chamber 17, the opened valve 5, the chamber 1 8 and the connection 26 to the second milk beaker pair.

As is evident from Fig. 5, a pressure decay takes place in the working chamber 1 6 in correspondence with the curve from I to II.

On reaching the switching point II, according to Fig. 2, switching-over of the diaphragms 7 and 8 and thereby of the valve 10 takes place, so that vacuum is present at the corresponding milk beaker pair through the chambers 19 and 18 and the connection 26. After further pressure decay according to the curve Il-Ill, switching-over of the valve 9 takes place at the switching point lil through the diaphragm 6 as shown in Fig. 3. Thereby, a connection of fresh air supply exists through the bore 21, the valve seat 3, the chamber 14, the connection 22 to one milk beaker pair and through the duct 23 to the stabilizing chamber 20 and through the duct 24 and the throttle 25 to the working chamber 16. The pressure rise in the working chamber 1 6 ensues according to the curve Ill-I without switching of the valve 10.On attainment of the switching point I, switching-over of the valve 9 takes place as shown in Fig. 4 through the diaphragm 6, so that vacuum is present through the chambers 1 5 and 1 4 and the connection 22 at the milk beaker pair and through the duct 23 reduces the pressure in the stabilizing chamber 20. Thereby, the diaphragms 7 and 8 switch the valve 10 over instantaneously through the pressure still existing in the working chamber 16. Thus the initial setting is again attained and a new cycle begins.

Fig. 6 shows a second embodiment of the present invention. The two valve units are arranged beside each other and there are two chamber for the constant vacuum, which is connected through a duct 32. The vacuum connection 27 and the fresh air supply bore 21 are both redundant. The function of the vacuum connection 27 and fresh air supply bore 21 is taken over by chambers 30, which are connected by the duct 31. The valve seat 3 is replaced by a valve seat 33. Two working chambers 1 6 are separated and connected with each other through a duct 34.

Figs. 7 to 10 show a third embodiment of the present invention. The embodiment comprises a housing 101, in which valve seats 102, 103, 104 and 105 are disposed. Diaphragms 106, 107 and 108 are firmly clamped and the valve members 109 and 110 are movably arranged in the housing 101. The diaphragm 106 is connected with the valve member 109 through a linkage 111. The diaphragms 106 and 107 are coupled with each other through a linkage 11 2.

The diaphragm 108 is connected with the valve member 110 through a linkage 113. A stabilizing chamber 114 is disposed between the housing 101 and the diaphragm 107. A working chamber 11 5 is bounded by the diaphragms 106, 107 and 108 and the housing 101. A chamber 116 of the constant vacuum is disposed between the diaphragms 106 and 108, the valve seats 103 and 105 and the housing 101. The valve seats 102 and 103 bound a chamber 11 7 for alternating pressure, which is connected with a milk beaker connection 11 9. The valve seats 104 and 105 bound a chamber 11 8 for alternating pressure at an outlet 1 20. The valve seats 102 and 104 are constantly in communication with the atmosphere through a connection 121.Vacuum sumply to the chamber 11 6 takes place through a connection 1 22. A duct 1 23 leads unthrottled from the outlet 1 20 to the stabilizing chamber 114. A duct 1 25 with a throttle 1 24 connects the working chamber 11 5 with the duct 1 23.

As Fig. 7 shows, vacuum prevails in the chambers 116, 11 7 and 118 and thereby also in the outlets 11 9 and 1 20 as well as in the chamber 11 4 through the connection by the duct 1 23. The air is slowly sucked out of the working chamber 11 5 through the throttle 1 24 and the duct 1 25. As is evident from Fig. 5, the pressure decays according to the curve from I to Ill.After reaching the switching point II, the switching-over of the plate valve 109 takes place by way of the diaphragm 106 and 107, so that the outlet 11 9 communicates through the connection 121, the valve seat 102 and the chamber 11 7 with the fresh air (Fig. 8).

Afte further pressure decay according to the curve Il-Ill, the switching-over of the valve 110 takes place in the switching point Ill by way of the diaphragm 108 and the linkage 11 3 and the pulsator assumes the setting shown in Fig. 9. The outlet 1 20 communicates through the connection 121, the valve seat 104 and the chamber 11 8 with the fresh air. An unthrottled pressure rise takes place in the chamber 114 through the duct 123 so that a sudden switching-over of the valve 109 (Fig. 10) occurs.Thus, there is a vacuum at the output 11 9 through the connection 122, the chamber 116, the valve seat 103 and the chamber 11 7. After a pressure rise according to the curve Ill-I, switching-over of the valve 110 in the switching point I occurs. At this instant, the starting point for the next cycle is again reached.

Fig. 11 shows a fourth embodiment of the present invention in which a connection 221 for the fresh air is disposed at the chamber 226 and a connection 222 for the vacuum at the chamber 227. The chamber 226 is formed by the diaphragm 106 and 108 as well as valve seats 228 and 229. The chamber 227 is formed by valve seats 230 and 231 and a housing 201.

It is an advantage of the embodiments described above by way of example that there is provided an alternating cycle diaphragm pulsator with phase displacement, in which the phase relationship is substantially independent of the cyclic rate of the pulsator and other influencing magnitudes and is cheap in the manufacture. Also the pulsator has a valve system, which operates with only one settable throttle and in which the described defects of the prior art are excluded.

Claims (15)

1. An alternating cycle diaphragm pulsator for a milking machine, comprising wall means defining a housing, a first diaphragm coupled to a first valve member to form a first diaphragm-valve unit, a second diaphragm coupled to a second valve member to form a second diaphragm-valve unit, and a third diaphragm coupled to the second diaphragmvalve unit to define a first chamber with the second diaphragm-valve unit and a stabilizing chamber with a first portion of the wall means, the stabilizing chamber being -in communication through duct means with a second chamber formed by the first diaphragm-valve unit and the duct means communcating through throttle means with a working chamber defined by surfaces of the first and the second diaphragm and a second portion of the wall means.

2. A pulsator as claimed in claim 1, wherein the first and second diaphragm valve units are arranged behind each other.

3. A pulsator as claimed in either claim 1 or claim 2, wherein the two diaphragm-valve units are each associated with a respective fresh air and vacuum connection.

4. A pulsator as claimed in claim 1, wherein the two diaphragm-valve-units are arranged parallel to each other.

5. A pulsator as claimed in claim 4, wherein the first chamber communicates with a source of underpressure and with a third chamber associated with the first diaphragmvalve unit and the second chamber communicates with a source of fresh air and with a fourth chamber associated the second diaphragm-valve unit

6. A pulsator as claimed in claim 5, wherein the first and third chambers are disposed adjacent each other and the second and fourth chambers are disposed adjacent each other.

7. A pulsator as claimed in either claim 5 or claim 6, wherein the first and third chambers are separated from each other by a third portion of the wall means, and the second and fourth chambers are separated from each other by a fourth portion of the wall means and communicate with each other through an opening in the fourth portion of the wall means.

8. A pulsator as claimed in any one of claims 5 to 7, wherein the source of underpressure is disposed between the first and second diaphragms and valve members, and the source of fresh air is disposed opposite a face of one of the valve members.

9. A pulsator as claimed in any one of claims 5 to 7, wherein the source of underpressure is disposed opposite a face of the second valve member and the source of fresh air is disposed between the first diaphragm and a valve seat for the first valve member.

10. A pulsator substantially as hereinbefore described with reference to Figs. 1 to 4 of the accompanying drawings.

11. A pulsator substantially as hereinbefore described with reference to Fig. 6 of the accompanying drawings.

1 2. A pulsator substantially as hereinbefore described with reference to Figs. 7 to 10 of the accompanying drawings.

1 3. A pulsator substantially as hereinbefore described with reference to Fig. 11 of the accompanying drawings.

14. A pulsator substantially as hereinbefore described with reference to Figs. 7 to 10 of the accompanying drawings.

15. A pulsator substantially as hereinbefore described with reference to Fig. 11 of the accompanying drawings.