Valves and valve actuation – Electrically actuated valve – Including solenoid
Patent
1995-09-29
1997-05-13
Lee, Kevin
Valves and valve actuation
Electrically actuated valve
Including solenoid
251 3005, F16K 3106
Patent
active
056284918
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention concerns a pilot valve. The pilot valve controls the pneumatically actuated main valve of a milking-system pulsator. An electromagnet is alternately energized and de-energized, displacing an armature back and forth between each end of a stroke. At one end the armature seals an air-supply line and at the other end a vacuumizing line. The lines are accordingly alternately connected to a valve chamber. The valve chamber communicates with the main valve through a control channel. The armature is connected to a diaphragm such as to provide axial guidance for the armature without friction.
A valve of this type is known for example from U.S. Pat. No. 4,196,751. The diaphragm in this valve is on the end of the armature opposite the electromagnet. To ensure that the air-supply line can be sealed, the surface of the armature is provided with an appropriate seal. The diaphragm is also in the form of a spring that opposes the motion of the armature toward the air-supply line with considerable resistance. Powerful reversing forces are necessary to overcome this resistance.
A valve is known from German U 9 114 953.3 wherein the armature extends through a diaphragm on the end opposite the electromagnet. When the magnet is energized, the armature is attracted to it and maintained there by remanence. Powerful reversing forces are necessary to overcome the remanence. This valve is only intended to control the flow of a medium, and it is not appropriate for connecting a control channel alternately to an air-supply line and a vacuumizing line.
SUMMARY OF THE INVENTION
The object of the present invention is a pilot valve that will be inexpensive to manufacture and does not require powerful reversing forces.
This object is attained in accordance with the present invention in that the diaphragm is made of a resilient material and is interposed between the armature and the electromagnet such that, when the armature is at one end of its stroke, it seals off the air-supply line.
A diaphragm made of resilient material makes it possible to displace the armature with relatively feeble forces. Interposing the diaphragm between the armature and the magnet prevents the armature from adhering to the magnet due to remanence. The diaphragm must in this event be made of a non-magnetic material, rubber for example. The reversing forces can be very weak because of the lack of friction and remanence. Since the diaphragm can seal off the air-supply line, no extra seal is necessary, which is a very economical result.
The armature is attached to the diaphragm in another advantageous embodiment of the present invention by an elevation on the diaphragm and a bore in the armature. This approach not only allows cost-effective attachment but also eliminates the need for an extra seal because the elevation seals off the vacuumizing line while the armature is at one end of its stroke.
The diaphragm in another advantageous embodiment is provided with a vent, through which the valve chamber communicates with another valve chamber, into which the air-supply line opens. No special communicating channel will accordingly be necessary.
It is of advantage for the diaphragm to have a bead that seals off the valve chambers from the atmosphere. No special seals will accordingly be necessary.
BRIEF DESCRIPTION OF THE DRAWING
The present invention will now be specified with reference to the accompanying drawing, which comprises a single FIGURE, which is a cross-sectional view of a valve according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
A valve 1 is provided with an electromagnet 2. Electromagnet 2 itself is provided with an air-supply line 3. Air-supply line 3 can be sealed off by . . . one end of its stroke. Diaphragm 4 is provided with a vent 9. Air-supply line 3 communicates with a valve chamber 10 through vent 9. A control channel 11 extends out of valve chamber 10. Air-supply line 3 opens into another valve chamber 13. Diaphragm 4 is surrounded by a bead 12 that seals off first valve cha
REFERENCES:
patent: 3498330 (1970-03-01), Paige
patent: 4196751 (1980-04-01), Fischer et al.
patent: 4875499 (1989-10-01), Fox
patent: 4969629 (1990-11-01), Athanassiu
Lee Kevin
Westfalia Separator Aktiengesellschaft
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