Valves and valve actuation – Fluid actuated or retarded – Pilot or servo type motor
Patent
1979-12-06
1982-09-28
Rosenthal, Arnold
Valves and valve actuation
Fluid actuated or retarded
Pilot or servo type motor
251 30, 251 45, F16K 3140, F16K 31385
Patent
active
043515096
DESCRIPTION:
BRIEF SUMMARY
There already exist known valves with servo-command, consisting of a seat and a main poppet valve mounted in a valve body, with the movements of the poppet valve being controlled by a moving piece which causes the pressure prevailing in a control chamber to change, said chamber being supplied with fluid under pressure through a passage connecting it with a pressurized fluid intake conduit, passage of the fluid being controlled by the valve, such controlled passage allowing for release from the control chamber through an exhaust system.
In such known valves, at the moment the valve closes the fluid pressure upstream from the seat increases under the effect of the braking thereof. This results in very rapid closing of the poppet valve at the end of the sequence and thus gives rise to hydraulic recoil or water hammer as it is commonly known.
The object of the present invention is to substantially decrease the intensity of this hydraulic recoil and thereby to permit more gentle and gradual closing of the valve.
To that end, the valve according to the invention is characterized by the fact that the intake passage of the fluid under pressure into the control chamber includes an intake conduit which opens across from the edge of the seat which is upstream in relation to the flow of the fluid passing in the valve, said conduit having its mouth near the smallest cross-section area of passage of fluid in the valve in all the possible positions of the poppet valve in relation to the seat.
The attached drawing shows schematically and by way of example one way of executing the valve which is the subject of the invention.
FIG. 1 shows this valve in a cross section in the open position.
FIG. 2 corresponds to FIG. 1, but shows the valve in the closed position.
The valve includes a body 1 which has two ducts 2 and 3 for intake of the fluid under pressure and exhaust of that fluid, respectively. The fluid arriving via duct 2 enters a ring-shaped chamber 4 surrounding a main seat 5 through which the fluid passes to reach the exhaust duct 3. Passage of the fluid around the seat 5 is controlled by the a poppet valve 6, the movements of which are governed by the effects of the pressure existing in a control chamber 7.
The poppet valve consists of a circular member 8 the central part of which has a passage 9 at one end of which is located a secondary seat 10. This seat 10 may be engaged by a fluid-tight gasket 11 mounted in a movable core 12, the movement of which, inside a tube 13, is caused by a magnetic field generated by a coil (not shown).
The poppet valve 6 is guided by an elastic washer 15 which fits between a seat 16 in the body 1 and a blocking bolt 17. The washer 15 fits, on its inside edge, into a groove 18 in the circular member 8.
Closing of the seat 5 is ensured by a fluid-tight gasket 19, which is ring-shaped, wedged into a housing 20 on the lower surface of piece 8 and held into position by a bushing 21. This gasket 19 has, on its periphery, notches 22 which serve as an intake conduit and provide a connection between the chamber 4 and a ring-shaped slot 23 provided in the housing 20. A calibrated channel 24 in the poppet valve 6 permits a connection between said ring-shaped slot 23 and the chamber 7 located above the poppet valve 6.
The core 12 is pushed toward the poppet valve 6 by a coil spring 25, pressing the gasket 11 against the seat 10. The fluid pressure in the chamber 4 is transmitted to chamber 7 by passing through the notches 22, the ring-shaped slot 23 and the calibrated channel 24. There results a force tending to move the poppet valve 6 in a direction causing the gasket 19 to press against the seat 5.
FIG. 2 shows the valve in the closed position, and it is readily apparent that the notches 22 are open across from the edge of the seat 5, which is upstream in relation to the flow of fluid. In this location, which is close to being the smallest passage for fluid in the valve body for all the possible positions of the poppet valve in relation to the seat 5, the speed of the fluid increases sharply just
REFERENCES:
patent: 1521354 (1924-12-01), Burns
patent: 3076630 (1963-02-01), Hammond
patent: 3784154 (1974-01-01), Ostrowski
patent: 3872878 (1975-03-01), Kozel et al.
Groff, Jr. Emory L.
Rosenthal Arnold
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