Duplex cam-operated pressure-balanced sleeve valve

A duplex cam-operated pressure-balanced sleeve valve is provided for controlling fluid flow into either one or both of two fluid lines, such as to either one or both of two filter elements, comprising, in combination; (1) a valve housing; (2) first and second valve chambers in the housing in alignment with a cam chamber therebetween; (3) first, second, and third fluid flow ports in the housing communicating with the first valve chamber, and fourth, fifth, and sixth fluid flow ports in the housing communicating with the second valve chamber; (4) a first reciprocable sleeve valve member in the first valve chamber, axially movable within the first valve chamber between positions controlling flow from the first fluid port to one or both of the second and third fluid flow ports; (5) a second reciprocable sleeve valve member, preferably coaxial with the first sleeve valve member, in the second valve chamber axially movable within the second valve chamber with the first sleeve valve member between positions controlling flow from one or both of the fourth and fifth fluid flow ports to the sixth fluid flow port; (6) cam-following valve-actuating means in the cam chamber operatively connected to both the first and second sleeve valve members, for reciprocably moving both valve members together between their flow-controlling positions; (7) a cam in the cam chamber movable between at least three selected positions and operatively connected with the cam-following valve-actuating means in a manner such that: (a) with the cam in a first position, the first sleeve valve member is in a position communicating one of the second and third fluid flow ports with the first fluid flow port and the second sleeve valve member is in a position communicating one of the fourth and fifth fluid flow ports with the sixth fluid flow port; (b) with the cam in a second position, the first sleeve valve member is in a position communicating the other of the second and third fluid flow ports with the first fluid flow port and the second sleeve valve member is in a position communicating the other of the fourth and fifth fluid flow ports with the sixth fluid flow port; (c) with the cam in a third position, both the first and second sleeve valve members are in positions communicating the first with the second and third fluid flow ports and the fourth with the fifth and sixth fluid flow ports; (8) means for moving the cam between each of the selected positions, thereby shifting the valves in unison; (9) the first and second sleeve valve members each having an interior pressure-receiving surface exposed at all times to fluid pressure in the first and second valve chambers, respectively, and in the first and sixth fluid flow ports, respectively, and an exterior pressure-receiving surface exposed to fluid pressure in the second and third, and fourth and fifth fluid flow ports, respectively, fluid flow through which is controlled by the respective sleeve valves, so that there is a zero component of force arising from any pressure differential across the valves tending either to move the sleeve valve members or to resist cam-operated movement of the sleeve valve members between their selected positions; (10) the cam-following valve actuating means having opposed pressure-receiving surfaces, of which one is exposed to fluid pressure in the first valve chamber, and the other is exposed to fluid pressure in the second valve chamber; (11) the opposed pressure-receiving surfaces of the cam-following valve-actuating means being of such small relative surface areas that any fluid pressure differential between first and second valve chambers on the opposed pressure-receiving surfaces thereof offers negligible resistance to cam-operated reciprocation of the sleeve valve members, so that such fluid pressure differential does not interfere with movement of the first and second sleeve valve members between their selected positions.

Having regard to the foregoing disclosure, the following is claimed as patentable and inventive embodiments thereof:

1. A duplex cam-operated pressure-balanced sleeve valve for controlling fluid flow from one fluid line into either one or both of two fluid lines, comprising, in combination;

(1) a valve housing;

(2) first and second valve chambers in the housing in alignment with a cam chamber therebetween;

(3) first, second, and third fluid flow ports in the housing communicating with the first valve chamber, and fourth, fifth, and sixth fluid flow ports in the housing communicating with the second valve chamber;

(4) a first reciprocable sleeve valve member in the first valve chamber, axially movable within the first valve chamber between positions controlling flow from the first fluid port to one or both of the second and third fluid flow ports;

(5) a second reciprocable sleeve valve member, preferably coaxial with the first sleeve valve member, in the second valve chamber axially movable within the second valve chamber with the first sleeve valve member between positions controlling flow from one or both of the fourth and fifth fluid flow ports to the sixth fluid flow port;

(6) cam-following vlave-actuating means in the cam chamber operatively connected to both the first and second sleeve valve members, for reciprocably moving both valve members together between their flow-controlling positions;

(7) a cam in the cam chamber movable between at least three selected positions and operatively connected with the cam-following valve-actuating means in a manner such that:

(a) with the cam in a first position, the first sleeve valve member is in a position communicating one of the second and third fluid flow ports with the first fluid flow port, and the second sleeve valve member is in a position communicating one of the fourth and fifth fluid flow ports with the sixth fluid flow port;

(b) with the cam in a second position, the first sleeve valve member is in a position communicating the other of the second and third fluid flow ports with the first fluid flow port, and the second sleeve valve member is in a position communicating the other of the fourth and fifth fluid flow ports with the sixth fluid flow port;

(c) with the cam in a third position, both the first and second sleeve valve members are in positions communicating the first with the second and third fluid flow ports and the fourth with the fifth and sixth fluid flow ports;

(8) means for moving the cam between each of the selected positions, thereby shifting the valves in unison;

(9) the first and second sleeve valve members each having an interior pressure-receiving surface exposed at all times to fluid pressure in the first and second valve chambers, respectively, and in the first and sixth fluid flow ports, respectively, and an exterior pressure-receiving surface exposed to fluid pressure in the second and third, and fourth and fifth, fluid flow ports, respectively, fluid flow through which is controlled by the respective sleeve valves, so that there is a zero component of force arising from any pressure differential across the valves tending either to move the sleeve valve members or to resist cam-operated movement of the sleeve valve members between their selected positions;

(10) the cam-following valve actuating means having opposed pressure-receiving surfaces, of which one is exposed to fluid pressure in the first valve chamber, and the other is exposed to fluid pressure in the second valve chamber;

(11) the opposed pressure-receiving surfaces of the cam-following valve-actuating means being of such small relative surface areas that any fluid pressure differential between first and second valve chambers on the opposed pressure-receiving surfaces thereof offers negligible resistance to cam-operated reciprocation of the sleeve valve members, so that such fluid pressure differential does not interfere with movement of the first and second sleeve valve members between their selected positions.

2. A duplex sleeve valve according to claim 1, in which the first and second sleeve valve members are fixed to and movable with first and second reciprocable transfer shafts, respectively, each of which is attached to the cam-following valve-actuating means and moves therewith along their respective valve chambers.

3. A duplex sleeve valve according to claim 2 in which the cam-following valve-actuating means defines an internal track along which the cam travels in moving between its selected positions.

4. A duplex sleeve valve according to claim 2 in which the housing defines internal walls separating the first and second valve chambers from the cam chambers, and having a central passage therethrough, and the transfer shafts extend through and are reciprocably movable within the passage.

5. A duplex sleeve valve according to claim 1 in which each of the tubular sleeve valve members is cylindrical.

6. A duplex sleeve valve according to claim 1 in which the valve members are concentric with their respective valve chambers and coaxial with each other, the first and sixth fluid flow ports, and the cam chamber and cam-following valve-actuating means.

7. A duplex sleeve valve according to claim 1 in which the valve chambers adjacent the first and sixth fluid ports each carry coaxial tubular seal guards biased towards and reciprocably movable with the sleeve valve members.

8. A duplex sleeve valve according to claim 7 in which the valve chamber, sleeve valve members and seal guards are all cylindrical.

9. A duplex filter assembly comprising two filter assemblies arranged in parallel with each in series valve-controlled fluid flow connection with a fluid line in a manner such that either one filter assembly at a time or both filter assemblies together receives fluid flow from and returns fluid flow to the line, and a duplex sleeve valve according to claim 1 controlling flow to and from the fluid line and each filter assembly.

10. A duplex filter assembly according to claim 9, in which the filter assemblies each comprise:

(a) a housing having a fluid inlet and fluid outlet, a filter chamber, and fluid flow passages interconnecting the inlet and outlet and the filter chamber; and

(b) a filter element disposed in the filter chamber across the line of flow between the inlet and the outlet in a manner such that all flow between the inlet and the outlet must pass through the filter.

11. A duplex filter assembly according to claim 10 in which the filter chamber is defined by a filter cannister removably attached to the housing, and the filter elements are cylindrical, with end caps at each end.