GB2133503A

GB2133503A - Valve

Info

Publication number: GB2133503A
Application number: GB08332296A
Authority: GB
Inventors: Karl-Heinz Zettier
Original assignee: Westfalia Separator GmbH
Current assignee: GEA Mechanical Equipment GmbH
Priority date: 1982-12-11
Filing date: 1983-12-02
Publication date: 1984-07-25
Also published as: DE3245901A1; JPS6240067B2; SE8306345L; DK492583A; GB2133503B; DK492583D0; GB8332296D0; IE832778L; SE8306345D0; DE3245901C2; IE54764B1; JPS59130552A

Abstract

The cream discharge of a centrifuge for skimming milk is adjusted to the desired concentration value by means of a valve 1 having a variable throttle cross-section which is set to a minimum by an adjusting screw 3. An axially movable valve member 4 is subject to product action in chamber 17 and compressed air action in chamber 12, the pressure in chamber 12 being initially set to that in product chamber 17, which can be read off monometer 18. If the pressure on the product side increases, the valve member 4 is displaced towards the compressed air side, so that the throttle cross-section 7 is increased and the pressure is again reduced. This prevents inadmissibly high cream concentration. In the case of a partial or complete emptying of the centrifuge, a piston 5 is pressed by compressed air against a conical shoulder 13 of valve member 4 and holds it in position until the end of the emptying process so that the correct setting is immediately obtained when separation recommences. <IMAGE>

Description

SPECIFICATION Valve for regulating the cream concentration in a centrifuge for skimming milk The invention relates to a valve for regulating the cream concentration in a centrifugeforskimming milk,thetrottle cross-section of the valve being automatically increased with increasing discharge pressure ofthe cream phase.

For example, such a valve is known from U.S. Patent 2 145 544, the throttle cross-section being completely closed when there is no cream flow. When cream flow starts, the throttle cross-section only opens against an adjustable spring pressure, when the force produced by the discharge pressure of the cream is greater than the set spring tension. Although this valve makes it possible to setthe discharge pressure of the cream to a constant value, it does not make it possible to keep the outflowing cream quantity constant. As a function of theft content ofthe milk, which can vary considerably,theoutflowing cream has a different concentration and consequently also a different viscosity, so that different quantities can flow out, despite the constant cream pressure.

Particularly in the case of the now preferably used centrifuges with self-discharging drums, different discharge values are set on the cream side after each emptying operation, because during the emptying operation the valve is completelyclosed and when separation recommences, there is an indeterminate ratio of the outflow quantity and viscosity at the preselected pressure.

The procedure is therefore onlyto carry out a constant pressure regulation in the case of skimmed milkoutflowfrom the centrifuge, because there can be no great viscosity changes here. Cream discharge is then preferably regulated with a valve which can be set to a constant throttle cross-section. However, here again there is a dangerthatwith increasing fat content of the milk, the possible cream concentration will be exceeded, so that part of the cream is removed with the skimmed milk. This not only leads to corresponding cream losses, but also to a clogging of the centrifugal drum. It is therefore necessa ry to set the cream concentration either continuously by hand, or automatically with very expensive control equipment.

The problem ofthe present invention is to provide a valve of the aforementioned type, in which it is not possible to d rop drop belowthethrottlecross-section of the valve set at the start of separation.

This problem is solved in thatthe throttle crosssection ofthe valve can be set once andforall to a minimum value by means of an adjusting screw.

According, to an advantageous embodiment of the invention,the adjusting screw can be locked by a locking screw. The automatic increase in the throttle cross-section is brought about by an axially displaceable valve seat, which is supplied with products on one side and with compressed air on the other side, the two valve seat surfaces being of the same size and a pressure reducing valve with a manometer and a through-way valve being associated with the compressed air connection.

According to another advantageous embodiment, during the automatic emptying ofthe centrifugal drum, the valve seat is locked by a compressed air-operated piston, which can be pressed on to a conical shoulder ofthe valve seat. The compressed air connection is provided with a through-wayvalve and the piston chamberofthe piston is connected by means of a channel with the compressed air chamber ofthe valve seat. The product chamber of the valve is connected to a manometer, which makes it possible in a simple manner two bring about a state of equilibrium by setting the same pressure values of the sides of the valve seatsubiectto product action on the one hand and compressed air action on the other.

The invention is described hereinafter relative to the drawings, wherein show: Fig. a section through the valve.

Fig. 2 the arrangement ofthe valve on a centrifuge for skimming milk.

Valve 1 comprises valve casing 2, adjusting screw 3, valve seat 4, piston 5 and valve cover 6. Between adjusting screw 3 and valve seat 4 is provided a throttle cross-section 7. Compressed air connection 8 is associated with valve seat4 and compressed air connection 9 with pistonS. Piston chamber 10 ofthe piston 5 is connected by means of a channel 11 with the compressed air chamber 12 of valve seat 4. The valve seat4 has a conical shoulder 13, against which can be engaged piston 5. Adjusting screw 3 is secured against automatic adjustment by means of a locking screw 14. Product is supplied through the inlet connection 15 and is removed through the discharge connection 16. Product chamber 17 of valve 1 is connected to manometer 18.A limit switch 19 is arranged in valve cover 6 and enables the actuation of valve seat 4.

It can be gathered from Fig. that valve 1 is arranged in the cream discharge line 20 of centrifuge 21. A pressure reducing valve with manometer 22 and athrough-wayvalve 23 are associated with the compressed air connection 8 of valve 1, whilst compressed air connection 9 is only provided with a through-way valve 24. A constant pressure valve 26 is arranged in the skimmed milk discharge line 25.

Firstly the discharge pressureforthe skimmed milk is set with the constant pressure valve 26, the adjusting screw 3 of valve 1 being fully open. By opening through-wayvalve 23, valve seat 4 is exposed to the full compressed air pressure and is consequently displaced until it abuts in the direction of product chamber 17. If correct skimmed milkdischarge pressure has been set, by means of adjusting screw 3 of valve 1, the cream outflow is set in such a way that the desired cream concentration is obtained. The pressure prevailing in product chamber 17 of valve 1 is now read off manometer 18 and the same pressure is setforthe compressed air on pressure reducing valve 22. The forces on both sides of valve seat 4 are now in equilibrium. If there is a pressure rise in product chamber 17, the piston is automatically displaced towards the compressed air side and consequently increases inthrottlecross-section 7 of valve 1,so that a larger quantity of cream can flow out and an inadmissibly high cream concentration is prevented.

Before there is a partial or complete emptying of centrifuge 21, through-wayvalve 24 automatically opens and by means ofthe compressed air, piston 5 is pressed against the conical shoulder 13 ofvalve seat 4.

Thus, the valve seat is fixed in position, in the case of a pressureless product chamber during emptying, so thatwhen separation recommences, the correct settings ofthe cream discharge is immediately obtained. Atthe end of emptying,thethrough-way valve 24 closes again and piston 5 is moved back into its initial position by means of the pressure built up in piston chamber 10 by means of channel 11.

If valve seat4 is moved so fartowards the compressed air side that it engages on valve cover 6, limit switch 19triggers an alarm. The operatorthen knows that he must open wide the adjusting screw 3.

List of reference numerals 1 Valve 2 Valve casing 3 Adjusting screw 4 Valve seat 5 Piston 6 Valve cover 7 Throttle cross-section 8 Compressed air connection 9 Compressed air connection 10 Piston chamber 11 Channel 12 Compressed air chamber 13 Shoulder 14 Locking screw 15 Inlet connection 16 Outlet connection 17 Product chamber 18 Manometer 19 Limit switch 20 Cream outflow 21 Centrifuge 22 Pressure reducing valvewith manometer 23 Through-wayvalve 24 Through-wayvalve 25 Skimmed milk discharge 26 Constant pressure valve

Claims

1. Avalve for regulating the cream concentration in a centrifuge for skimming milk, the throttle cross- section of the valve being automatically enlarged with an increasing discharge pressure of the cream phase, wherein the throttle cross-section of valve can be set once and for all to a minimum value by means of an adjusting screw.

2. Avalve according to claim 1, wherein the adjusting screw is locked against automatic adjustment by a locking screw.

3. Avalve according to claims 1 or 2, wherein the valve seat is arranged in an axially displaceable manner.

4. Valve according to one or more ofthe claims 1 to 3, wherein on one side the displacement of valve seat takes place by means of product and on the opposite side by means of compressed air.

5. Avalve according to one or more ofthe claims 1 to 4, wherein a pressure reducing valve with a manometer ar;d a through-way valve are associated with the compressed air connection ofthe valve seat.

6. Avalve according to one or more of the claims 1 to 5, wherein the surfaces of the valve seat subject to the action ofthe product on the one hand and the compressed air on the other are ofthe same size.

7. A valve according to one or more of the claims 1 to 6, wherein the position ofthe valve seat is locked during the automatic emptying ofthe centrifugal drum.

8. Avalve accordingto one or more of the claims 1 to 7, wherein the valve seat is locked by a compressed air-operated piston.

9. Avalve according to one or more ofthe claims 1 to 8, wherein the compressed air connection of the piston is provided with a th rough-way valve.

10. Avalve according to one or more ofthe claims 1 to 9, wherein the piston chamber of the piston is connected to the compressed airchamberofvalve seat by means ofthe channel.

11. Avalve according to one or more ofthe claims 1 to 10, wherein the valve seat is provided with a conical shoulder.

12. A valve according to one or more ofthe claims 1 to 11, characterized in that the product chamber is connected to a manometer.

13. Avalve according to one ofthe claims 1 to 12, wherein a limit switch is provided in valve cover and is operated bythevalve seat, as soon as the latter engagesonthevalvecover.