Fluid control system

Claim 2

A fluid powered servo control system responsive to a plurality of redundant, command input signals and comprising: a source of fluid under pressure; a plurality of conduits communicating with the source of fluid under pressure; a plurality of fluid amplifiers each operative in response to a respective command signal, each having a fluId inlet connected to a respective one of the conduits and first and second fluid outlets, and each comprising means receiving fluid from the source of fluid under pressure and ejecting fluid proportionally through the two outlets in response to a respective command signal to cause a differential pressure output signal across the outlets, the fluid outlets of each fluid amplifier being fluidly isolated from the outlets of the other fluid amplifiers; a housing; a movable structure slideably mounted within the housing and comprising means summing the output signals of the fluid amplifiers, the movable structure having a plurality of pairs of piston face areas, each pair corresponding to a respective fluid amplifier, each piston face area comprising means for receiving fluid pressure from a respective one of the fluid amplifier outlets; and a plurality of differential pressure monitoring means, each monitoring means being connected to the piston face areas of a respective one of the pairs of piston face areas and responsive to any differential pressure thereacross, each monitoring means being connected to a respective one of the conduits in series between the source of fluid under pressure and the corresponding fluid amplifier and comprising a means, functionally independent of the movement of the movable summing structure, for shutting off fluid flow to the respective fluid amplifier upon the occurrence of a differential pressure, between the outlets of the respective fluid amplifier, which exceeds a predetermined level.

Claim 3

The apparatus of claim 1, each fluid amplifier comprising an electrohydraulic transducer means producing a differential fluid pressure which, absent corresponding movement of the movable structure, corresponds to an input command which comprises a variable electrical signal.

Claim 4

The apparatus of claim 1, further comprising a flow control valve having a movable valve element, the movable summing structure being operatively connected to the movable element of the flow control valve.

Claim 5

The apparatus of claim 1, each differential pressure monitoring means comprising: a valve housing having a chamber and having, in communication with the chamber, first, second, third, and fourth ports and at least one drain opening, the third and fourth ports having communication with the respective outlets of the corresponding, associated fluid amplifier, the first port communicating with the source of fluid under pressure and the second port communicating with the fluid inlet of the respective fluid amplifier; a valve member slideably mounted within the valve housing chamber and movable therein within first, second, third, fourth, and fifth positional ranges, the valve member having a passageway which communicates between the first and second ports upon the valve member being positioned within its third positional range, the valve member having valving means for shutting off fluid flow between the first and second ports upon the valve member being positioned within its first positional range and, alternatively, upon the valve member being positioned within its fifth positional range; pressure responsive means, responsive to any differential pressure between the first and second fluid outlets of the respective, associated fluid amplifier, for constraining the valve member within its third positional range when any difference between the pressure level within the fluid amplifier first outlet and the second outlet is below a predetermined amount, for moving the valve member from its third to its second positional range upon the pressure in the first outlet falling below that in the second outlet by the predetermined amount, and for moving the valve member from its third to its fourth positional range upon the pressure within the second outlet falling below that in the first outlet by the predetermined amount; and latching means, for moving the valve member from its second to its first positional range upon the valve member entering its second positional range, and for moving the valve member from its fourth to its fifth positional range upon the valve member entering its fourth positional range.

Claim 6

The apparatus of claim 4, the pressure responsive means including means for moving the valve member from its first to its third positional range and, alternatively, from its fifth to its third positional range, upon fluid flow into the valve through the first port being shut off.

Claim 7

A fluid powered servo control system responsive to a plurality of redundant, command input signals and comprising: a source of fluid under pressure; a plurality of conduits communicating with the source of fluid under pressure; a plurality of fluid amplifiers each operative in response to a respective command signal, each having a fluid inlet connected to a respective one of the conduits and first and second fluid outlets, and each comprising means receiving fluid from the source of fluid under pressure and ejecting fluid proportionally through the two outlets in response to a respective command signal to cause a differential pressure output signal across the outlets, the fluid outlets of each fluid amplifier being fluidly isolated from the outlets of the other fluid amplifiers; a housing; a movable structure slideably mounted within the housing and comprising means summing the output signals of the fluid amplifiers, the movable structure having a plurality of pairs of piston face areas, each pair corresponding to a respective fluid amplifier, each piston face area comprising means for receiving fluid pressure from a respective one of the fluid amplifier outlets; and a plurality of differential pressure monitoring means, each monitoring means having fluid communication with each piston face area of a respective one of the pairs of piston face areas, each monitoring means being connected to a respective one of the conduits in series between the source of fluid under pressure and the corresponding fluid amplifier and comprising a means, functionally independent of the movement of the movable summing structure, for shutting off fluid flow to the respective fluid amplifier upon the occurrence of a differential pressure, between the outlets of the respective fluid amplifier, which exceeds a predetermined level.

Claim 8

A fluid powered servo control system responsive to a plurality of redundant, command input signals and comprising: a source of fluid under pressure; a plurality of conduits communicating with the source of fluid under pressure; a plurality of fluid amplifiers each operative in response to a respective command signal, each having a fluid inlet connected to a respective one of the conduits and first and second fluid outlets, and each comprising means receiving fluid from the source of fluid under pressure and ejecting fluid proportionally through the two outlets in response to a respective command signal to cause a differential pressure output signal across the outlets, the fluid outlets of each fluid amplifier being fluidly isolated from the outlets of the other fluid amplifiers; a housing; a movable structure slideably mounted within the housing and comprising means summing the output signals of the fluid amplifiers, the movable structure having a plurality of pairs of piston face areas, each pair corresponding to a respective fluid amplifier, each piston face area comprising means for receiving fluid pressure from a respective one of the fluid amplifier outlets; and a plurality of differential pressure monitoring means, each monitoring means having fluid communication with each piston face area of a respective one of the pairs of piston face areas, each monitoring means being connected to a respective one of the conduits in series between the source of fluid under pressure and the corresponding fluid amplifier and comprising a means, functionally independent of the movement of the movable summing structure, for shutting off fluid flow to the respective fluid amplifier upon the occurrence of a differential pressure, between the outlets of the respective fluid amplifier, which exceeds a predetermined level.