GB2104368A

GB2104368A - Combined control and collector unit for machine milking apparatus

Info

Publication number: GB2104368A
Application number: GB08218850A
Authority: GB
Inventors: Fritz Happel; Werner Happel
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-07-16
Filing date: 1982-06-30
Publication date: 1983-03-09
Also published as: FR2509572B1; CH657747A5; GB2104368B; FR2509572A1; DE3128162A1

Abstract

A combined control and collector unit for machine milking apparatus in which air is introduced into the milk collecting chamber 11 only during the relaxation pulse in order to simplify the matching to different levels of vacuum and to prevent air mixing with the milk that is removed. Air entry during the suction pulse is prevented and, as a result of the use of an adjustment spring 30 which is arranged on a membrane 10 actuated control spindle 15 and which is only operative during the relaxation pulse, exact adjustment of the level of relaxation is effected. <IMAGE>

Description

SPECIFICATION Combined control and collector unit for machine milking apparatus The invention relates to a combined control and collector unit for machine milking apparatus comprising a milk collector housing provided with connection nipples for connection with the inner chamber of milking cups and a connection for a milk line connected to a vacuum source; a control housing mounted on the milk collector housing with a membrane arranged therebetween to form a lower membrane chamber which is continuously connected to atmosphere and an upper membrane chamber which can be alternately connected to vacuum and atmosphere, the control housing having connection nipples for connection with the milking cup intermediate chambers and also a connection for pressurised air; a stepped closure piston connected to the membrane and extending with play into the milk collector housing; and a control unit which is arranged on the side of the membrane opposite to the piston, which has an adjustment spring and which connects the connection nipples associated with the milking cup intermediate spaces to either the upper membrane chamber or the pressurised air connection.

A control and collector unit of this kind is known from DE-OS 28 10 087.0.

This known control and collector unit guarantees during the relaxation pulses, i.e. in the phase between successive suction pulses, that the tests -are practically completely relieved by isolating them from the low pressure source.

It also guarantees a problem-free discharge of milk in which reverse washing effects are excluded as far as possible.

The known control and collector unit has proved itself useful in practice but is complicated from the technical manufacturing point of view and also requires specialist servicing because the interaction of the two springs associated with the closure piston must be accurately adjusted during servicing to ensure ideal operation of the closure piston.

The object underlying the present invention is thus to further deveiop the initially defined control and collector unit and to improve it in such a way that, while simplifying considerably its overall construction and thus its manufacture, it is possible, in simple manner, to adapt the unit to different levels of vacuum in individual milking plants so as to secure ideal operation, and so that disturbing mixing of air in the milk which is removed is avoided and the removal of the milk brought about by the applied vacuum is improved.

This object is solved in accordance with the invention in that the control unit-consists of a control spindle fixedly connected to the membrane and displaceable in a control sleeve, with the adjustment spring arranged at the free end of the control spindle; in that the adjustment spring is arranged between an adjustment member in the form of threaded nut and a plate braced against a control spindle abutment and displaceable along the control spindle; and in that the closure piston which extends into the milk collector housing carries a radially projecting seal which, in the upper end position of the piston corresponding to the suction pulse, closes the air inlet opening formed by the play between the piston and the wall of the housing.

The use of a single adjustment spring which, as a result of its arrangement, is operative only in the relaxation pulse simplifies not only the overall construction of the control unit but also means that a defined and accurate level of relief can be selected during dry running thereby making it possible to take account of the different levels of vacuum in individual milking plants without problem.

Preventing air entering into the milk collecting chamber during the suction pulse results in the advantages that undesired mixing of air with the milk is avoided and that the removal of milk in particular via risers in the subsequent line system is improved.

The plate which is displaceable on the control spindle against the force of the adjustment spring is preferably constructed as a switch plate for opening a valve associated with the pressurised air duct. In this way accurate and simple control of the pressurised air supply to the intermediate chambers of the milking cups is achieved and the control spindle and control sleeve can be compactly and simply constructed because these two elements only need to cooperate to control the introduction of vacuum into the intermediate chambers of the milking cup.

The end, remote from the membrane, of the control sleeve which guides the control spin dle is formed as an abutment for the switch plate, and the adjustment spring becomes operative during the relaxation phase after the time at which the switch plate has contacted this abutment. In this connection it is particularly advantageous for the control sleeve to be fixed relative to the control housing by means of resilient O-rings so that a damping action favourable to the stressing of the parts is obtained when the switch plate contacts the abutment.

The control spindle has a reduced crosssection forming a control groove in the region of the control sleeve, and the control sleeve, in addition to radially extending bores provided with a non-return valve, is preferably of crown-iike shape in the region of its end which forms an abutment for the switch plate, with the openings that are created having the function of control edges. The introduction of vavuum into the intermediate chambers of the milking cups that it realised in this way leads to a particularly compact and simultaneously simple construction.

A special feature which is particularly advantageous having regard to simplification of the overall construction, servicing and basic adjustment resides in the fact that the control housing comprises a base part which has all the connection nipples and a removable, and preferably unscrewable, cap part which sursrrounds the adjustment spring. This cap part simultaneously serves to secure the valve body arranged at the inner end of the pressurised air passage so that this part is easily accessible and can be exchanged without difficulty.

In accordance with a further advantageous embodiment of the invention the milk collecting chamber is subdivided into a milk collecting chamber and a milk drainage chamber by a dividing wall which is inclined towards its center and provided with a central drain opening, with the closure piston being associated with the drain opening.

In this manner a milk collecting chamber is obtained above the dividing wall and a damping chamber beneath the dividing wall and this brings the advantage of lower air consumption at the change-over between the suction and relaxation pulses because the milk collecting chamber can be kept relatively small and the lower comparatively large damping chamber prevents congestion effects as the milk drains away.

The seal which is provided on the closure piston and which interrupts the air supply to the milk collecting chamber in the upper end position of the piston preferably extends sufficiently far in the radial direction beyond the gap which is to be sealed that, in the relaxation pulse when the gap is open, it forms an air guiding member which extends up to the peripheral zone region of the milk collecting chamber.

In this manner air flowing in during the relaxation pulse is guided directly to the peripheral region of the milk collecting chamber, and thus to the connection nipples leading to the inner chambers of the milking cups, with the important result that in this way no milk from the collecting chamber and thus from the other teats is flushed along by this air.

That part of the inflowing air which flows in the direction of the drain opening in the dividing wall assists in rapid clearance of the milk collecting chamber, i.e. in a rapid transfer of the milk from the milk collecting chamber into the damping chamber.

In the same way as the control housing is of two part construction the milk collector housing is also preferalby of two part construction which is achieved by providing a lower housing part which defines the damping chamber, an upper housing part which forms the milk collecting chamber and a dividing wall which is clampingly retained between these two parts.

It is of particular advantage, both from the point of view of manufacture and also assembly and servicing, that all the housing parts can be manUfactured without difficulty in synthetic material and that the mutual fixing of the individual housing parts can be realised by means of a single clamping hoop, because trouble-free mutual positioning and a secure assembly can be ensured by axially clamping together the housing parts which fit one within the other.

Further advantageous special features of the invention are set forth in subclaims.

The invention will now be explained in more detail with reference to an embodiment and the drawing, the single figure of which shows a schematic longitudinal section through a combined control and collector unit at the start of the message or relaxation pulse.

The combined control and collector unit consists of a control housing generaily indicated by the reference numeral 1 and a milk collector housing generally indicated by the reference numeral 2.

The milk collector housing is in turn an assembly of two housing parts, namely, a lower housing part 3 with a milk extraction nipple 1 3 opening into the base thereof, and also an upper housing part 9 provided with connection nipples 8, which are preferably uniformly distributed around its periphery and onto which the short milk hoses for connection with the inner chambers of the associated milking cups can be pushed.

A funnel-like dividing wall 39 with a central drain opening 40 is trapped between the lower housing part 3 and the upper housing part 9 and indeed with seals 41 being positioned therebetween.

This funnel-like dividing wall subdivides the milk collector housing into a milk collecting chamber 11 and a milk drainage or damping chamber 42. The volume of the milk drainage chamber 42 is preferably significantly larger than the volume of the milk collecting chamber 11.

The two housing parts 3 and 9 are held together by means of a clamp hoop 43 which is fastened to the control housing 1.

A membrane 10 is clamped between the control housing 1 and the milk collector housing 2 and indeed so as to form a lower membrane chamber 1 7 and an upper membrane chamber 1 9. By way of example this membrane 10 can consist of rubber, of fabric reinforced rubber, or of synthetic material.

The lower membrane chamber 1 7 is bounded by a wall 28 of the housing and is continuously connected to atmosphere via the air inlet opening 1 6.

The upper membrane chamber 1 9 which is formed in the housing part 4 of the control housing 1 has a connection 1 8 for a pulsator and is thus alternately connected to vacuum and atmosphere.

A closure piston 1 2 which extends downwardly with play through the wall 28 of the housing and into the milk collecting chamber 11 is fastened to center of the membrane 1 0.

This closure piston 1 2 is of stepped construction in the region of its free end so that it has an annular surface 34 at the zone of the transition from the largest diameter to the smallest diameter. Its end face 35 which cooperates with the drainage opening 40 in the dividing wall 39 is constructed so that it can close the opening 40 in the lower end position of the closure piston 1 2.

An annular groove 37 into which a seal 14 is inserted is provided in the region of the transition to the reduced piston cross-section, but still in the part with the large crosssection. This seal 14 serves, in the upper end position of the piston 12, i.e. during the suction phase, to seal the annular air inlet 27 formed as a result of play between the piston 1 2 and the wall 28 of the housing.

The seal takes over a further function as a result of the fact that it extends radially up to the marginal zones of the milk collecting chamber 11 which means that it acts as an air guiding element and, as the flow arrows indicate, guides the air which enters through the air inlet 27 in the open condition directly to the milk hose connection nipples and also into the peripheral zones of the milk collecting chamber.

The control housing 1 is of two part construction and consists of a housing part 4 which has all the connection nipples and a cap part 5 which preferably can be unscrewed. The nipples associated with the housing part 4 are the nipples which lead to the milking cup intermediate chambers, a nipple 31 which leads to a pressure source, and also the pulsator connection nipple 1 8.

A control spindle 1 5 is centrally arranged at the side of the membrane 10 opposite to the closure piston 1 2 and is screwed to the closure piston 1 2. The control spindle 1 5 cooperates with a switching or control sleeve 26 which is radially mounted with a small amount of play and is held by means of two elastic O-rings 6 to a ring-like projection 38 of the housing part 4. This results in a reliable sealed support which allows a small degree of movement to compensate for tolerances and ensures simple installation and removal of the switching sleeve. The cooperation of the control spindle 1 5 and the control sleeve 26 brings about the periodic introduction of vacuum into the milking cup intermediate chambers during the suction pulse.For this purpose the control spindle 1 5 is provided in the region of the control sleeve 26 with a control groove 7 obtained by a reduction in crosssection. The control groove 7 cooperates with openings 23 which extend through the central region of the wall of the control or switching sleeve and with transverse openings 22 in the upper end region of the control sleeve. The upper openings 22 of the control sleeve are preferably realised by a crown-like formation of the end of the control sleeve. A non-return valve 24 is associated with the openings 22 and prevents air at atmospheric pressure passing, via the openings 22 and the connection nipples 21, into the milking cup intermediate chambers at the beginning of the massage or relaxation pulse and causing premature collapse of the respective teat rubbers.

A switching plate 32 is displaceably arranged on the free end of the control spindle 1 5. An adjustment spring 30 is positioned between this switch plate 32 and an adjustment member 25 which is preferably constructed as a threaded nut. The lower end position of the switch plate 32 is determined by an abutment 20 provided on the control spindle 1 5. The bias of the spring 30 is adjustable by means of an adjustment nut 25.

A valve lying at the inner end of the pressure source connection nipple 31 is controlled by the switch plate 32. This valve consists of a stem or push rod 29 and a valve body 33.

The valve is fixed in position by the threaded cap 5 which also surrounds the adjustment spring and the adjustment nut 25 so that, after unscrewing the cap part 5, the adjustment nut is freely accessible and adjustments can be effected.

All housing parts including the threaded cap preferably consist of plastic material and can be reliably and permanently connected together by simply plugging them together axially and subsequently engaging the clamping hoop 43. Thus the dismantling necessary for cleaning purposes and reassembly of the individual parts can be carried out rapidly and without problems.

The manner of operation of the combined control and collector unit will now be described in the following.

It has already been mentioned that a pulsator which alternately applies atmospheric pressure and vacuum to the upper membrane chamber is connected to the connection nipple 1 8 which opens into this chamber. Furthermore, it has already been explained that the connection nipple 31 is continuously connected to a pressure source which supplies the pressurised air required for the relaxation pulse.

If a vacuum prevails in the upper membrane chamber 1 9 the membrane 10 will be curved upwardly as a result of the atmospheric pressure prevailing in the lower membrane chamber 17, with the result that the piston 1 2 moves away from the drain opening 40 and the control spindle 1 5 is displaced upwardly. This results in a connection of the upper membrane chamber 19, which is connected to vacuum, with the intermediate chambers of the milking cups and indeed via the connection nipples 21, the annular space 36, the openings 22, the control groove 7 provided in the control spindle 15, the openings 23 in the wall of the control sleeve and also via the non-return valve 24.The described flow path is created as soon as the edge which bounds the control groove 7 has moved over the corresponding edge of the transverse opening 22.

During this phase of connection of the upper evacuated membrane space with the intermediate chambers of the milking cups the pressurised air valve 29, 33 is closed because the switch plate 32 has moved upwardly together with the control spindle 1 5.

In the described suction phase in which the membrane and also the control spindle move upwardly the closure piston 1 2 also moves upwardly and indeed until the seal 1 4 contacts the air entry slot 27. This means that during the suction or milk extraction phase no air can flow from the lower membrane chamber 1 7 via the gap 27 into the milk collecting chamber 11.

This is of advantage because no air is mixed with the milk which flows into the milk collecting chamber during the suction phase and, because air only enters during the relaxation pulse, air cushions which are practivally separated from one another form in the drain lines between the slugs or drops of milk which form. This type of air entry during the relaxation phase only also assists the transport of milk away from the milk collecting chamber in advantageous manner and has particularly favourable effects if risers are present in the milk drain lines.

Furthermore, the radial extent of the seal 14 fixed to the piston 1 2 results in air which flows in during the relaxation pulse being directed into the peripheral zone of the milk collecting chamber. This ensures that the relief air is directed directly to the respective connection nipples 8 and thus to the inner chambers of the milking cups without taking with it milk from the collecting chamber and thus from the other teats. At the same time the inflowing air which is downwardly deflected in the peripheral zone region assists in clearing the milk that is present from the milk collecting chamber 11 in the drainage direction and in transferring this milk into the damping chamber present beneath the dividing wall 39.

The air cushion which forms in the damping chamber 42 beneath the dividing wall 39 ensures the vacuum develops readily in the upper milk collecting chamber 11, even with a high milk flow, and indeed while simultaneously damping the transitions which occur at the change-over between vacuum and atmosphere (or approximately atmospheric pressure).

If atmospheric pressure is introduced into the upper membrane chamber via the nipple 18, atomospheric pressure is present both in the chamber 1 9 and also in the chamber 1 7 which lies beneath the chamber 1 9 so that the membrane 10 is moved downwardly towards the dividing wall 39 as a result of the subatmospheric pressure prevailing in the milk collecting chamber 11.

The control spindle 1 5 and thus the spring loaded switch plate 32 also partake in this movement of the membrane 10.

Before the switch plate 32 contacts the upper end of the control sleeve 26 which is fixed to the housing it actuates the valve stem 29, thereby opening the connection between the pressure source and the intermediate chambers of the milking cups. This connection takes place via the connection nipple 31, the valve 29, 33, the annular chamber 36 and the connection nipple 21. In this arrangement the valve seat 33 can be constructed as a restrictor.

In can be seen that the adjustment spring 30 is inactive during the suction pulse and first becomes operative when the switch plate 32 contacts the free end of the control sleeve 26 during the transition into the relaxation pulse. From this moment on the force of the adjustment spring 30 opposes the downward movement of the spring 10 and thus of the piston 1 2. The vacuum provided via the connection line 1 3 generates a downwardly directed force via the end face 35 of the piston 1 2 and its annular surface 34, and indeed in dependence on the level of the prevailing vacuum when compared with atmospheric pressure. This force acts against the force of the adjustment spring which can be changed by means of the adjustment nut 25.

At the adjustment nut side the switch plate 32 is shown with an abutment 44 which is preferably of resilient material and which can also be formed by a resilient ring.

As a result of this arrangement the adjusted level of relief at the teats remains almost constant during the massage or relaxation pulse, and indeed independently of different throughflow quantities, volume changes and leaks of the chambers which are connected with the milk collecting space 11 via the nipples 8. Different teat sizes, different milk hose lengths etc. are thus no longer abte to exert disadvantageous effects.

Atmospheric air enters into the milk collecting chamber 11 via the play or gap 27 between the piston 1 2 and the wall part 8, and indeed for the whole of the time in which the seal 1 4 leaves the entry slot free.

If no or only very little milk flows via the extraction line 1 3 the air which enters via the gap 27 has practically no effect because it is not able to produce any noticable reduction of the vacuum. At greater milk flows the crosssection of the discharge line 1 3 is however changed in such a way that it results in a reduction of the level of vacuum in the collect ing chamber 11. Through the milk flow dependent reduction of the vacuum a smaller force now acts on the surfaces 35, 34 of the piston 1 2 which has the consequence that the force relationships change in favour of the adjustment spring 30, which thereby regulates the downward movement of the piston in dependence on the throughflow of milk.

For the function of the total arrangement it is always important that the surfaces 34, 35 of the piston 1 2 which are acted on by the atmosphere are greater than the surface on which vacuum acts which, in the illustrated embodiment corresponds to the cross-sectional area of the opening 40.

The adjustment spring 30 is in other respects dimensioned so that the lifting force which it generates is larger than the tractive force generated by the vacuum at the end face 35 of the piston, so that lifting of the piston 1 2 from the seat 40 the end of the milking process is ensured and special release or lever devices are superfluous.

It is particularly advantageous that the transfer of the membrane movement to the closure piston and also to the control spindle is no longer disturbed by spring forces and that the adjustment spring 30 is only effective when its function is required, namely during the relaxation phase, to accurately set the permissible residual vacuum in the milk collecting chamber. This adjustment can be carried out during dry running and indeed quite simply by actuating the adjustment nut 25 after removing the threaded cap 5. In this manner it is possible to match the apparatus to the level of vacuum prevailing in the particular milking installation rapidly and without problem.

It is also of importance that a milk flow dependent control of the closure is achieved as a result of the cooperation of counteracting forces resu!ting from the vacuum, from the air inlet and from the adjustment spring, by making at least one of the forces which are in operation dependent on the strength of the milk flow. The relationships can always be chosen so that, all in all, ideal behaviour results which provides the best possible approximation to the conditions which prevail during natural calf suckling, in particular during the relaxation pulse, and thereby ensures that the milking cups are reliably retained on the teats. The improvement achieved in removing the milk and the prevention of air mixing with the removed milk represent further important advantages.

Claims

1. Combined control and collector unit for machine milking apparatus comprising a milk collector housing provided with connection nipples for connection with the inner chambers of milking cups and a connection for a milk drain line connected to a vacuum source; a control housing mounted on the milk collector housing with a membrane arranged therebetween to form a lower membrane chamber which is continuously connected to atmosphere and an upper membrane chamber which can be alternately connected to vacuum and atmosphere, the control housing having connection nipples for connection with the milking cup intermediate chambers and also a connection for pressurised air; a stepped closure piston connected to the membrane and extending with play into the milk collector housing; and a control unit which is arranged on the side of the membrane opposite to the piston, which has an adjustment spring and which connects the connection nipples associated with the milking cup intermediate spaces to either the upper membrane chamber of the pressurised air connection, characterised in that the control unit consists of a control spindle (15) fixedly connected to the membrane (10) and displaceable in a control sleeve (26), with the adjustment spring (30) arranged at the free end of the control spindle (15); in that the adjustment spring is arranged between an adjustment member (25) in the form of threaded nut and a plate (32) braced against a control spindle abutment (20) and displaceable along the control spindle (15); and in that the closure piston (1 2) which extends into the milk collector housing (2) carries a radially projecting seal (14) which, in the upper end position of the piston (12) corresponding to the suction pulse, closes the air inlet opening (27) formed by the play between the piston and the wall (28) of the housing.

2. Combined control and collector unit in accordance with claim 1 and characterised in that the plate (32) which is displaceable on the control spindle (15) against the force of the adjustment spring (30) is constructed as a switch plate for opening a valve (29, 33) associated with the pressurised air passage (31).

3. Combined control and collector unit in accordance with claim 1 or claim 2 and characterised in that the end, remote from the membrane (10), of the control sleeve (26) which guides the control spindle (15) is formed as an abutment for the switch plate (32).

4. Combined control and collector unit in accordance with one or more of the preceding claims and characterised in that the control sleeve (26) is fixed relative to the control housing (1) by means of resilient O-rings (6).

5. Combined control and collector unit in accordance with one of the preceding claims and and characterised in that the control spindle (15) has a reduced cross-section forming a control groove (7) in the region of the control sleeve; and in that the control sleeve (26), in addition to radially extending bores (23) provided with a non-return valve (24), has at least one further opening (22) which defines a control edge in the region of its end which forms an abutment for the switch plate (32).

6. Combined control and collector unit in accordance with claim 5 and characterised in that the end of the control sleeve (26) which forms an abutment for the switch plate (32) is of crown-like shape.

7. Combined control and collector unit in accordance with one or more of the preceding claims and characterised in that the control housing (1) comprises a base part (4) which has all the connection nipples (31, 31, 18) and a removable cap part (5) which surrounds the adjustment spring (30).

8. Combined control and collector unit in accordance with one of the preceding claims and characterised in that the cap part (5) simultaneously serves to fix the valve body (33) arranged at the inner end of the pressurised air passage (31).

9. Combined control and collector unit in accordance with one or more of the preceding claims and characterised in that the milk collecting housing (2) is subdivided into a milk collecting chamber (11) and a milk drainage chamber (42) by a dividing wall (39) which is inclined towards its center and provided with a central drain opening; and in that the closure piston (12) is associated with the drain opening (40) in the dividing wall.

1 0. Combined control and collector unit in accordance with claim 9 and characterised in that the volume of the milk drainage chamber (42) is larger than the volume of the milk collection chamber (11).

11. Combined control and collector unit in accordance with one or more of the preceding claims and characterised in that the seal (14) which is provided on the closure piston (12) and interrupts the air supply to the milk collecting chamber (11) in the upper end position of the piston. extends sufficiently far in the radial direction beyond the gap (27) which is to be sealed that, in the relaxation pulse when the gap (27) is open, it forms an air guiding member which extends up to the peripheral zone region of the milk collecting chamber (11).

1 2. Combined control and collector unit in accordance with claim 9 and characterised in that the dividing wall (39) which is of funnellike construction has separating webs which extend, in particular in rag-like form, between the various connection nipples (8) of the milk collecting chamber (11).

1 3. Combined control and collector unit in accordance with one or more of the preceding claims and characterised in that the milk collector housing (2) comprises a lower housing part (3) and an upper housing part (9) and the dividing wall (39) which is clampingly retained between these two parts.

14. Combined control and collector unit in accordance with one or more of the preceding claims and characterised in that the various housing parts, between which seals (41) are arranged, are fixed together by a clamping hoop (43).

1 5. A combined control and collector unit substantially as herein described with reference to and as illustrated in the accompanying drawings.