NZ238321A - Claw bowl for milking machine: configuration of shut-off valve - Google Patents

Description

23232/ PATENTS FORM NO. 5 Fee No. 4: $260.00 PATENTS ACT 1953 COMPLETE SPECIFICATION -6 MAY J992.V •V? After Provisional No: 238321 Dated: 29th Mav 1991 CLAW BOWL iTc: fc> Vrc WE N NU PULSE NEW ZEALAND a diviaion of Alfa-Laval (NZ> Limitod, a New Zealand company of 31 Bandon Street, Hamilton, New Zealand hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: 1 23 8 32 This invention relates to claw bowls.

In our New Zealand patent application No. 229021 we describe a claw bowl which is designed to provide improved milk flow. The claw bowl described in our New Zealand patent specification No. 229021 includes a shut-off valve.

Shut-off valves of the type described in our aforementioned New Zealand patent specification commonly have a problem with leakage which occurs when the valve is in the off (seated) position. Such leakage occurs where the stem of the valve passes through the claw bowl body because vacuum downstream of the outlet which draws extraneous matter into the outlet via the aperture through which the shut-off valve stem projects. Such leakage may also have an undesirable effect on vacuum stability in the milking plant.

It is an object of the present invention to address the above-mentioned difficulty.

Further objects and advantages of the present invention will become apparent from the ensuing description which is given by way of example.

According to the present invention there is provided a claw bowl comprising a body, inlets to the body and an outlet from the body, a fluid shut off valve for opening and closing an aperture said valve comprising a valve head and valve stem, said valve stem being slidably supported in a valve guide such that said valve head may move between an open position wherein said aperture is opened, and a closed position wherein said aperture is closed by sealing engagement of a first sealing surface of said valve head with a peripheral surface of said aperture, characterised in that said valve head further comprises a second sealing su 2 ?3 8 3 sealingly engages with a peripheral surface of said guide when said valve head is in said closed position.

The said valve head and valve stem are axially symmetric bodies fixedly and coaxially connected together, and said first sealing surface of said valve head comprises an axially symmetric sealing surface which sealingly engages with said peripheral surface of said aperture.

The second sealing is an axially symmetric surface.

The fluid shut off valve can have a rest member provided adjacent to said valve guide, said rest member being fixedly supported relative to said valve guide, and said valve stem is provided with a positioning member, the arrangement being such that said positioning member may engage with said rest member when said valve head is in an open position, thereby maintaining said valve head in an open position.

The aperture can be formed between a first chamber and an outlet and said first sealing surface seals against an interior surface of said first chamber.

The valve guide can be formed in a wall portion of said outlet, and said second sealing surface prevents passage of fluid from said valve guide to the interior of said outlet, when said valve head is in said closed position.

The valve head can be moulded from synthetic material and said valve stem is manufactured in plastics or stainless steel.

The rest member can comprise a stem which fixedly engages in a socket formed integral with a portion of said first chamber. 3 23 8 32 i Aspects of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figures 1 and 2: are cross-sectional drawings of the claw bowl with the shut-off device in open and closed positions respectively, and Figure 3: Figure 3a: Figure 4: is a side view of a positioning member for the claw bowl, and is a plan view of the positioning member of Figure 3, and is a cross-section of the shut-off valve of the present invention shown separated from the claw bowl.

With respect to the drawings a claw bowl in accordance with the present invention comprises a body generally indicated by arrow 1, inlets 2 to the body, and an outlet 3. During milking milk is received via the inlets 2 and 15 is removed from the claw bowl via the outlet 3.

The claw bowl body incorporates a shut-off valve generally indicated by arrow 4. A rest generally indicated by arrow 5 is positioned close to the outlet 3.

An upper peripheral edge 6 of the claw bowl has a flange which is used to 20 join the claw bowl with a pulsator or claw top section top (not shown).

The shut-off valve 4 comprises a valve head 7, a valve stem 8 and a valve positioning member 9. The shut-off valve has two operative positions being the open position as illustrated by Figure 1 and a closed position as illustrated by Figure 2. The valve head 7 is moulded from & synthetic kT Etf V /* | 25 jAu . n 23® 32 material such as plastics, nylon or rubber as is the positioning member 9 whilst the valve stem 8 is manufactured in plastics or stainless steel.

The valve head 7 has a dome-shaped upper surface portion 10 and a first valve face 11 having an inclined surface complimentary to the inclined 5 surfaces of the body onto which it rests. The valve head also includes a cylindrical portion 12 mounted on the valve stem 8. The lower face 13 of the cylindrical portion 12 incorporates a ring seal 14.

When the shut-off valve 4 is in a closed position (Figure 2) the lower face 13 seals over the entrance to an aperture 15 in the lower wall of the claw bowl 10 just prior to the valve face 11 sealing on the adjacent sides of the interior surfaces of the claw bowl 1. The ring seal 14 compresses just prior to sealing being effected between the valve face 11 and the interior walls of the claw bowl.

The positioning member 9 is a tab shaped member having an engaging lip 15 16 with two locking ribs 17 which lock on a complimentary portion of the adjacent rest 5. Rest 5 comprises a tubular portion 19 which extends from the claw bowl body, stepped V-shaped member 18 and a stem 20 which extends into the tube 19.

The claw bowl described is injection moulded in a clear plastics material. 20 The aperture 15 which accommodates valve stem 8 is drilled out after moulding. All wall sections of the claw bowl are substantially the same thickness. The valve head 7, positioning member 9, stepped member 18, and stem 20 are moulded in a softer compressible material. Ring seal 14 can be integral with the valve head or may be a separate O-ring (not 25 shown). 23 8 3 2) When the shut-off valve 4 is in its closed position the face 11 seals on adjacent surfaces of the claw bowl body 1 isolating the interiors of the body from the outlet 3 whilst simultaneously face 13 seals on body surfaces adjacent the aperture 15 preventing unwanted entry of extraneous materials which could be sucked through the space between aperture 15 and stem 8 into outlet 3.

Aspects of the present invention have been described by way of example only and it will be appreciated that modifications and additions thereto may be made without departing from the scope of the invention as defined in the appended claims.

Claims (1)

1. WHAT WE CLAIM IS: 10 2. 15 20 4. A claw bowl comprising a body, inlets to the body and an outlet from the body, a fluid shut off valve for opening and closing an aperture said valve comprising a valve head and valve stem, said valve stem being slidably supported in a valve guide such that said valve head may move between an open position wherein said aperture is opened, and a closed position wherein said aperture is closed by sealing engagement of a first sealing surface of said valve head with a peripheral surface of said aperture, characterised in that said valve head further comprises a second sealing surface which sealingly engages with a peripheral surface of said guide when said valve head is in said closed position. A claw bowl as claimed in claim 1 wherein said valve head and valve stem are axially symmetric bodies fixedly and coaxially connected together, and said first sealing surface of said valve head comprises an axially symmetric sealing surface which sealingly engages with said peripheral surface of said aperture. A claw bowl according to claim 1 or claim 2 wherein said second sealing surface comprises an axially symmetric surface. A claw bowl according to claim 3, wherein a rest member is provided adjacent to said valve guide, said rest member being fixedly supported relative to said valve guide, and said valve stem is provided with a positioning member, the arrangement being such that said positioning member may engage with said rest member when said valve head is in an open position, thereby maintaining said v; in an open position. 7 23 8 3 2 1 5. A claw bowl according to claim 4 wherein said aperture is formed between a first chamber and an outlet and said first sealing surface seals against an interior surface of said first chamber. 6. A claw bowl according to claim 5 wherein said valve guide is formed 5 in a wall portion of said outlet, and said second sealing surface prevents passage of fluid from said valve guide to the interior of said A ~ outlet, when said valve head is in said closed position. 7. A claw bowl according to claim 6 wherein said valve head is moulded from synthetic material and said valve stem is manufactured in 10 plastics or stainless steel. 8. A claw bowl according to claim 7 wherein said rest member comprises a stem which fixedly engages in a socket formed integral with a portion of said first chamber. 9. A claw bowl substantially as described herein with reference to the 15 accompanying drawings. £ L\rwT£fc> oc£» NU PULSE NEW ZEALAND-A-DIVISION OF ALFA LAVAL (NZ) -LIMITED by their Attorneys 2^ JAMES & WELLS fW 'An ft 94 %}}