US3669137A

US3669137A - Fluid actuated piston valve

Info

Publication number: US3669137A
Application number: US63861A
Authority: US
Inventors: Colin John Kirk
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-08-26
Filing date: 1970-08-14
Publication date: 1972-06-13
Anticipated expiration: 1989-06-13
Also published as: NL7012418A; NL160921C; DE2041869A1; GB1289995A; FR2059192A5; JPS4914812B1; NL160921B

Abstract

A piston valve of the kind in which a piston is movable longitudinally of a housing having ports for fluid to be controlled by the piston between two operative positions in each of which at least some of said ports are interconnected in different pairs through passages in the piston, by actuating fluid pressure applied to the end of the piston appropriate to the movement required, the actuating fluid pressure for effecting the movement in one direction being applied from a source externally of the valve and the actuating fluid pressure for effecting movement in the other direction being derived from one of said ports when the piston has been moved in said one direction. Said one port is connected to an end portion of the housing adjacent the relevant end face of the piston through a restricted passage and a closable control orifice leads from the passage between the restriction therein and said end portion of the housing, the control orifice being openable to prevent the actuating fluid pressure from rising sufficiently to effect movement of the piston in said other direction and closable to permit the actuating fluid pressure to reach a value sufficient to effect movement of the piston in said other direction when said movement is to be effected.

Description

United States Patent Kirk [54] FLUID ACTUATED PISTON VALVE [72] Inventor: Colin John Kirk, Whispers," 125 Dukes Ride, Crowthorne, England 7 [22] Filed: Aug. 14, 1970 [21] Appl. No.: 63,861

[30] Foreign Application Priority Data Aug. 26, 1969 Great Britain.... ..42,403/69 [52] U.S.Cl. ..l37/l19,9l/189, 137/624.18, 137/625.61 [51] int. Cl ..FlSb 21/02 [58] Field oiSenrch ..137/87,115, 119, 625.61, 624.18; 91/189 [56] References Cited UNITED STATES PATENTS 3,457,941 7/1969 Cook ..417/307 X 3,565,114 2/1971 Rousseau... .....91/189X 2,625,136 1/1953 Moog ..137/625.6l 2,934,765 4/1960 Carson... ..137/625.61 3,055,383 9/1962 Paine .137/62561 X 3,509,899 5/1970 Hewson ..137/87 OTHER PUBLICATIONS 1 June 13, 1972 Primary Examiner-M. Cary Nelson Assistant Examiner-David J. Zobkiw Attomey-Mawhinney & Mawhinney ABSTRACT A piston valve of the kind in which a piston is movable longitudinally of a housing having ports for fluid to be controlled by the piston between two operative positions in each of which at least some of said ports are interconnected in different pairs 1 through passages in the piston, by actuating fluid pressure applied to the end of the piston appropriate to the movement required, the actuating fluid pressure for effecting the movement in one direction being applied from a source externally of the valve and the actuating fluid pressure for effecting movement in the other direction being derived from one of said ports when the piston has been moved in said one direction. Said one port is connected to an end portion of the housing adjacent the relevant end face of the piston through a restricted passage and a closable control orifice leads from the passage between the restriction therein and said end portion of the housing, the control orifice being openable to prevent the actuating fluid pressure from rising sufiiciently to effect movement of the piston in said other direction and closable to permit the actuating fluid pressure to .reach a value sufficient to efiect movement of the piston in said other direction when said movement is to be effected.

4 Claims, 7 Drawing Figures n1 g g PATENTEDJUN13 I972 3.669.137

sum 1 or a FIGZB.

INVENTag 4 COLIN JOHN \qzvr PATENTEDJUH13 I972 3,669.13 7

sum 2 OF 3 MVENTQ Couw JOHN \KR' PATENTEDJUN 1 3 I972 sum 3 0F 3 Co mu JQ FLUID ACTUATED PISTON VALVE The invention relates to a piston valve of the kind comprising a housing having a plurality of ports in its peripheral wall between which theflow of fluid is controlled by a piston in the housing, the piston being movable longitudinally of the hous ing between two operative positions, in each of which at least some of said ports are interconnected in different pairs through passages in said piston, by actuating fluid pressure applied to one or other end of the piston according to the direction of movement required.

It has been proposed hitherto to apply an actuating fluid pressure to one end face of a piston of such a valve through a separate control valve and a fixed restrictor, a control orifice leading to atmosphere being provided between the piston housing and the fixed restrictor such that when the control valve admits actuating fluid through the fixed restrictor and the control orifice is uncovered, there will be a loss of actuating fluid pressure through the open control orifice and the piston will not be moved and that when the control orifice is covered, the actuating fluid pressure will increase to a suffrcient value to actuate the piston. Such an arrangement has the disadvantage that after the piston has been moved, the actuating fluid pressure will continue to be applied to the end face of the piston and may increase further until the control valve has been operated to interrupt the supply of actuating fluid. An object of the invention is to provide a piston valve of the foregoing kind in which the actuating fluid supply is self-cancelling when the actuating fluid pressure hasincreased sufficiently to move the piston valve.

According to the invention a piston valve comprises a housing having a plurality of ports in its peripheral wall between which flow of fluid is controllable by a piston in the housing, the piston being movable longitudinally of the housing between two operative positions in each of which at least some of said ports are interconnected in different pairs through passages in said piston, by actuating fluid pressure applied to the end of said piston appropriate to the movement required,

- the actuating fluid pressure for effecting the movement in one direction being applied from a source externally of the valve and the actuating fluid pressure for effecting movement in the other direction being derived from one of said ports when said piston has been moved in said one direction, said one port being connected to an end portion of the housing adjacent the relevant end face of the piston through a restricted passage, a closable control orifice leading from said passage between the restriction therein and said end portion of the housing, the control orifice being openable to prevent the actuating fluid pressure from rising sufficiently to effect movement of the piston in said other direction and closable to permit the actuating fluid pressure to reach a value sufficient to efiect movement of the piston in said other direction when said movement is to be effected.

Conveniently there are at least three said ports in said housing, these ports being respectively an inlet port to which a fluid to be controlled by the valve is connected, an outlet port for said fluid and said one port, the piston having a passage therein which in one operative position of the piston interconnects said inlet port with said outlet port to permit flow of said fluid through the valve and in the other operative position in terconnects said inlet port with said one port, instead of said outlet port, thereby interrupting flow of said fluid through the valve and instead providing the actuating fluid pressure for effecting movement of said piston in said other direction when said control orifice is closed.

The housing may have other inlet and outlet ports arranged to be'interconnected by passages in said piston, where desired.

At least a pair of piston valves as set out in either of the two immediately preceding paragraphs may be so interconnected that an outlet port of one of the valves provides the actuating fluid pressure for effecting movement of the piston of the or another of the valves in said one direction and an outlet port of said other of the valves is connected to an inlet port of said one or yet another valve, said inlet port being connected through the piston of that valve to said one port thereof to provide the actuating fluid pressure for effecting movement of the piston thereof in said other direction.

By way of example, a piston valve, in accordance with the invention, and its operation will now be described with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 shows a conventional piston valve;

FIGS. 2A and 28 respectively show a valve in accordance with the present invention in its two operating positions;

FIGS. 3, 4 and 5 are diagrams'illustrating the sequential operation of the valve shown in FIG. 2 in moving from one operating position to the other, and

FIG. 6 is a diagram showing four valves of the kind shown in FIG. 2 interconnected for automatic operation in sequence.

Referring to FIG. 1, the conventional valve comprises a housing 1 containing a piston (not shown) which is movable between two operative positions in accordance with actuating fluid pressure applied at either the end 2 or 3 in accordance with the direction of movement required. The housing 1 is provided with inlet and outlet ports A, B, C andD which are interconnected in pairs through passages in the piston depending upon which operating position the piston is in. The piston is moved in the direction of the end 2 by fluid pressure applied from an external source to the end 3 and it is moved towards the end 3 by fluid pressure applied at the end 2. The fluid pressure applied to the end 2 is derived from a source4 admitted by means of a control valve 5 to a passage 6 containing a fixed restriction 7. Between the fixed restriction 7 and the end of the housing 2 there is an orifice 8 leading to atmosphere. When the piston has been moved by the application of actuating fluid at the end 3 to the position in which it is adjacent the end 2, actuating fluid may be applied through the valve 5 to the passage 6. Assuming that the operating orifice 8 is open, the fluid pressure will remain at substantially atmospheric pressure but when the operating orifice 8 has been closed, the pressure will increase until the piston is: moved toward the end 3 of the housing. When this has occurred it is necessary to release the control valve 5 so that the actuating fluid will be exhausted from the valve 5 through an outlet port 9. However, if the control valve 5 is not released, the fluid pressure will be maintained in the end portion 2 of the housing and may increase so long as the operating orifice 8 is closed. This is a disadvantage.

Referring to FIGS. 2A and 2B, the valve in accordance with this invention comprises a housing 11 having

end portions

12 and 13 and inlet and outlet ports A, B, C and D all similar to the corresponding ports in the conventional valve of FIG. 1. However, in accordance with the present invention, the housing has an additional outlet port F (the aforesaid one" port) and also has an outlet port E. The outlet port F is connected by a passage 16 containing a fixed restrictor 17 to the end portion 12 of the housing 11. A control orifice 18 leading to atmosphere is connected between the fixed restrictor l7 and the end 12 similarly to the control orifice :8 as shown in FIG. I. When the piston 10 has been moved (as shown in FIG. 2A) towards the end 12 of the housing 11 by actuating fluid pressure applied at the end 13, the inlet port C will be connected through the passage in the piston to the outlet port F and so actuating fluid will be applied to the end 12 of the housing 1 1. As long as the operating orifice 18 is open, the fluid pressure applied at 12 will be substantially atmospheric but when the control orifice 18 is closed, the actuating fluid pressure will increase until the piston l0 has been moved (as shown in FIG. 28) towards the end 13 of the housing 11. As soon as this movement has occurred, the port F will be disconnected from the inlet port C and therefore actuating fluid will automatically be disconnected from the end 12 of the housing 11. Therefore there can be no continued application of or increase of actuating fluid pressure due to failure to open a control valve such as valve 5 in the valve of FIG. 1 and so the pressure in the passage 16 is limited automatically to the maximum pressure required to move the piston from the end 12 of the housing 11 towards the end 13.

Turning now to FIGS. 3, 4 and 5, the valve shown in FIG. 2 is again illustrated and furthermore the connections between ports through the piston in one operative position thereof have been indicated by full lines and the alternative connections between ports through the piston in the other operative position thereof have been indicated by broken lines. The operating orifice 18 has been indicated as a two-port control valve. In one extreme position of operation to which the piston has been moved by actuating fluid pressure applied at the end 13 is shown in FIG. 3 and in this position an inlet port A is connected to an outlet port 8; an inlet port D is connected to an outlet port E and an inlet port C is connected to the outlet port F which leads to the passage 16. As shown in FIG. 3 the port 18 is open and therefore the fluid applied through the port C leads to atmosphere and the pressure at the end 12 of the housing 11 is substantially atmospheric. Turning now to FIG. 4, the control valve 18 is closed and therefore the pressure in the passage 16 increases until it has reached a value sufficient to move the piston to the left as shown in FIG. 4 until the port B is connected to the port E and the port C is connected to the port D. During the transition of the piston from one position to the other, the port C will be in contact with both ports D and F as shown in FIG. 4. When the piston has been moved fully to the left, the port connections will be as shown in FIG. 5 and there will be no actuating fluid applied from the port C to the port F.

The valve shown in FIGS. 2 to 5 may conveniently be interconnected with at least two other valves. If, for example three such valves to be used, they may be so interconnected that an outlet port D of one of the valves provides the actuating fluid pressure applied at the end 13 of another of the valves for effecting movement of the piston thereof in one direction and an outlet port B of the other of the valves is connected to an inlet port C of said one valve and through the piston thereof to said one port F thereof to provide the actuating fluid pressure applied at the end 12 of the housing thereof for effecting movement of the piston of said one valve in said other direction.

FIG. 6 shows how four valves in accordance with the invention can be so interconnected as to give automatic operation alternately of two cylinders and 21. Each of the valves indicated by 12+, a, a+ and bis the same as the valve shown in FIGS. 2 to S. In each valve, the port A is connected to a source of pressure fluid and port E is an exhaust port to atmosphere. The port C of each valve is connected to the port B of the next valve in sequence; that is port B of valve b+ is connected to port C of b; port B of valve a is connected to port C of valve b+; port B of valve (1+ is connected to port C of valve aand port B of valve bis connected to port C of valve a+. Port D of valve b+ is connected to one end of a two-position valve 22 controlling cylinder 20 and to the end 13 of valve a+. Port D of valve a is connected to the opposite end of valve 22 and to the end 13 of valve b. Port D of valve a+ is connected to the end 13 of valve b+ and to one end of a valve 23 controlling cylinder 21. Port D of valve bis connected via an on/off control valve 24 to the end 13 of valve aand to the opposite end of valve 23. The control orifices 18 of each valve are indicated by the same reference letters as the valves; i.e. b+, a, 0+ and b. The orifices 18 associated with valve 0- and a+ are controlled differentially by a common closure member 25 movable by means of the piston of cylinder 20 and the orifices 18 associated with valves b+ and bare controlled differentially by a common closure member 26 actuated by the piston of cylinder 21.

The operation of the circuit is as follows: first the on/off control valve 24 is placed in the on position in which flow between the port D of valve band the control valve 23 is completed and the latter is moved to the opposite position to that illustrated. A pressure signal is then fed through the valve 23 causing cylinder 21 to move from the illustrated position into a position in which the closure member 26 will close the orifice 18 associated with valve b+. At the end of that movement, the valve b+ will be operated by pressure applied at the end 12 thereof and port C will be connected to port D and port B to port E. This will cause a pressure signal to be fed from port C to port D of valve 1H- causing actuation of valve 22 controlling the cylinder 20, thereby causing the closure member 25 to close the orifice 18 associated with valve a. At the same time actuating pressure is applied from port D of valve b+ to the end 13 of the housing of valve a+ causing it to reset to the position in which port A is connected to port B, port D is connected to port E and port C is connected to port F in valve a+. Due to the movement of the closure member 25 to cover the orifice 18 of valve 42-, valve ais moved in the direction causing ports C and C and B and E thereof to be connected and thereby causing valve 22 to be reversed and to move cylinder 20 to the position in which the closure member 25 again closes orifice 18 of valve a+. This causes operating pressure to be applied to the end 12 of valve a+ causing port C to be connected to port D and port B to be connected to port E. A signal is then fed through port C to port D of valve a+ to effect reversal of valve 23 to cause the closure member 26 of cylinder 21 to be moved to cover the orifice 18 associated with valve lrand also to cause valve 17+ to be reset to the illustrated position in which port A is to be connected to port B, port D to be connected to port E and port C to be connected to port F. When orifice 18 of valve 12- has been closed, the bvalve is then set to the position illustrated and a pressure signal is fed through port C to port D of valve bto pass a signal to the on/off control valve 24 and to reset valve ato the position in which port B is connected to port E and port C is connected to port D. If the on/off control valve 24 is left in the on position then the cycle of operations will recommence and continue indefinitely until the on/off valve 24 has been switched to the off position. In the latter case, the sequential operation will cease when the signal from the b valve is applied to the open on/off control valve 24. It will be seen that the valves 12+, a, 0+ and bare operated continuously in that order, provided the on/off control valve 24 is in the on" position, to effect reciprocation of the two

cylinders

20 and 21 alternately. It is the provision of the additional port F in each valve 17+, a-, a+ and b which causes automatic setting of the valves to enable the sequential operation of the circuit to be performed continuously so long as on/off switch 24 is in the on" position.

What I claim as my invention and desire to secure by Letters Patent of the United States is:

l. A piston valvecomprising a housing having a longitudinally-extending bore therein, a plurality of ports in the peripheral wall of said housing and communicating with said bore, a piston slidable longitudinally in the bore in the housing between two operative positions in each of which at least some of said ports are interconnected in different pairs through passages in said piston, means for applying a different source of actuating fluid pressure to respective ends of said piston, whereby the application of one of the sources of actuating fluid pressure to the end of said piston appropriate to the movement required will effect movement of the piston from one operative position to the other, wherein the improvement comprises one of said means for applying actuating fluid pressure for effecting the movement in one direction derives its fluid pressure from a source externally of the valve, and the other of said means for applying the actuating fluid pressure for effecting movement in the other direction comprises duct means communicating with one port to which a fluid pressure is applied from a source externally of the valve, said one port being one of one of said pairs of ports, through one of said passages in said piston when the latter has been moved in said one direction and an end portion of the housing adjacent the relevant end face of the piston, a restriction in said duct means, and a closable control orifice positioned externally of said valve and leading from said duct means between the restriction therein and said end portion of the housing, the control orifice being openable to atmosphere to prevent the actuating fluid pressure from rising sufficiently to effect movement of the piston in said other direction and closable to permit the actuating fluid pressure to reach a value sufficient to effect movement of the piston in said other direction when said movement is to be effected.

2. A piston valve as claimed in claim 1 in which the housing has at least three ports therein, the ports being respectively an inlet port to which a fluid to be controlled by the valve is connected, an outlet port for said fluid and said one port, one of said passages in the piston in one operative position of the piston interconnecting said inlet port with said outlet port to permit flow of said fluid through the valve and in the other operative position interconnecting said inlet port with said one port, instead of said outlet port, thereby interrupting flow of said fluid through the valve and instead providing the actuating fluid pressure for effecting movement of said piston in said other direction when said control orifice is closed.

3. A piston valve as claimed in claim 2 having further inlet and outlet ports interconnectable by another of said passages 6 in the piston.

4. A fluid circuit including four piston valves as claimed in claim 2, said piston valves being so interconnected that an outlet port of a first of said valves provides the actuating fluid pressure for effecting movement of the piston of a second of said valves in said one direction and an outlet port of a third of said valves is connected to an inlet port of a fourth of said valves, said inlet port being connected through the piston of said fourth valve to said one port thereof to provide the actuating fluid pressure for effecting movement of the piston thereof in said other direction, the circuit also including valve means for opening and closing the control orifices of the four piston valves in sequence

Claims

1. A piston valve comprising a housing having a longitudinallyextending bore therein, a plurality of ports in the peripheral wall of said housing and communicating with said bore, a piston slidable longitudinally in the bore in the housing between two operative positions in each of which at least some of said ports are interconnected in different pairs through passages in said piston, means for applying a different source of actuating fluid pressure to respective ends of said piston, whereby the application of one of the sources of actuating fluid pressure to the end of said piston appropriate to the movement required will effect movement of the piston from one operative position to the other, wherein the improvement comprises one of said means for applying actuating fluid pressure for effecting the movement in one direction derives its fluid pressure from a source externally of the valve, and the other of said means for applying the actuating fluid pressure for effecting movement in the other direction comprises duct means communicating with one port to which a fluid pressure is applied from a source externally of the valve, said one port being one of one of said pairs of ports, through one of said passages in said piston when the latter has been moved in said one direction and an end portion of the housing adjacent the relevant end face of the piston, a restriction in said duct means, and a closable control orifice positioned externally of said valve and leading from said duct means between the restriction therein and said end portion of the housing, the conTrol orifice being openable to atmosphere to prevent the actuating fluid pressure from rising sufficiently to effect movement of the piston in said other direction and closable to permit the actuating fluid pressure to reach a value sufficient to effect movement of the piston in said other direction when said movement is to be effected.

3. A piston valve as claimed in claim 2 having further inlet and outlet ports interconnectable by another of said passages in the piston.

4. A fluid circuit including four piston valves as claimed in claim 2, said piston valves being so interconnected that an outlet port of a first of said valves provides the actuating fluid pressure for effecting movement of the piston of a second of said valves in said one direction and an outlet port of a third of said valves is connected to an inlet port of a fourth of said valves, said inlet port being connected through the piston of said fourth valve to said one port thereof to provide the actuating fluid pressure for effecting movement of the piston thereof in said other direction, the circuit also including valve means for opening and closing the control orifices of the four piston valves in sequence.