Digital fluid flow control system

Claim 2

A digital fluid flow control system comprising: an upstream fluid manifold; a downstream fluid manifold; a plurality of individually actuatable digital valve elements each having a fluid flow passage interconnecting the upstream manifold to the downstream manifold, a stationary cage formed in the flow passage, the cage having a perforated side connecting the interior of the cage with one of the manifolds and an open end connecting the interior of the cage with the other manifold, a converging-diverging nozzle located in the flow passage at the open end of the cage, and a bistable plug in the passage positionable exclusive in an open state in which the plug permits fluid flow through the passage or a closed state in which the plug prevents fluid flow through the passage; and means responsive to a plurality of binary signals for selectively positioning the plugs of the respective valve elements in the open or closed state.

Claim 3

The system of claim 1, additionally comprising means for connecting the upstream and downstream manifolds to external plumbing through which fluid to be controlled flows, the sum of the cross-sectional areas of the nozzles being small enough relative to the external plumbing so the pressure difference between the manifolds is sufficiently high for all combinations of states of the plugs to render the pressure at the nozzles of the valve elements having plugs in the open state independent of the pressure in the downstream manifold.

Claim 4

The system of claim 1, in which the plug of each valve element rides up and down over its cage, the plug covering the perforated side of the cage in the closed state and uncovering the perforated side of the cage in the open state.

Claim 5

The system of claim 1, in which the open end of the cage connects the interior of the cage with the downstream manifold.

Claim 6

A digital fluid flow control system comprising: a source of compressible fluid at a first pressure; a fluid receiver at a second pressure lower than the first pressure; an upstream manifold; a downstream manifold; means for connecting the upstream manifold to the source; means for connecting the downstream manifold to the receiver; a plurality of individually actuatable, digital valve elements each having a flow passage from the upstream manifold to the downstream manifold flow restricting orifice means with a given cross-sectional area in the flow passage, a bistable plug, and means responsive to a binary electrical signal for positioning the bistable plug exclusively in a first position that prevents fluid flow through the passage or a second position that permits fluid flow through the passage; the sum of the given cross-sectional areas of the orifice means being sufficiently small relative to the connecting means so the pressure difference between the upstream and downstream manifolds when the plugs of all the valve elements are in the second position is high enough for fluid flow at sonic velocity through the orifice means of all the valve elements; means for sensing the dynamic conditions of the fluid in one of the manifolds; and means responsive to the sensing means for generating the binary electrical signals for positioning the plugs of the valve elements.

Claim 7

A digital fluid flow control system comprising: a source of compressible fluid at a first pressure; a fluid receiver at a second pressure lower than the first pressure; an upstream manifold; a downstream manifold; means for connecting the upstream manifold to the source; means for connecting the downstream manifold to the receiver; a plurality of individually actuatable, digital valve elements each having a flow passage from the upstream manifold to the downstream manifold flow restricting orifice means with a given cross-sectional area in the flow passage, a bistable plug, and means responsive to a binary electrical signal for positioning the bistable plug exclusively in a first position that prevents fluid flow through the passage or a second position that permits fluid flow through the passage; the sum of the given cross-sectional areas of the orifice means being sufficiently small relative to the connecting means so the pressure difference between the upstream and downstream manifolds when the plugs of all the valve elements are in the second position is high enough for fluid flow at sonic velocity through the orifice means of all the valve elements; means for sensing the dynamic conditions of the fluid in one of the manifolds; and means responsive to the sensing means for generating the binary electrical signals for positioning the plugs of the valve elements.

Claim 8

The system of claim 5, in which the orifice means of each valve element comprises the throat of a converging-diverging nozzle formed in the flow passage.

Claim 9

The system of claim 6, in which the diverging portion of each nozzle is long enough to contain the resulting shock wave for the maximum pressure difference between the upstream and downstream manifolds.

Claim 10

The system of claim 5, in which the orifice means is a sharp edged orifice and the minimum pressure difference is higher than the critical pressure ratio of the fluid.

Claim 11

The system of claim 5, in which the orifice means of at least some of the valve elements vary in accordance with a geometric progression.

Claim 12

The system of claim 5, in which the given cross-sectional areas of the flow restricting orifice means are smaller than the cross-sectional area of the remainder of the flow passages.

Claim 13

A digital fluid flow control system comprising: a source of fluid at a first pressure; a fluid receiver at a second pressure lower than the first pressure; means for sensing the dynamic fluid conditions in the system; means responsive to the sensing means for generating a plurality of binary signals; a plurality of digital valve elements, each valve element having a fluid flow passage interconnecting the source to the receiver, flow determining orifice means in the passage, and means responsive to one of the binary signals for placing the valve element exclusively in an open state in which fluid flows through the passage or a closed state in which no fluid flows through the passage, the flow determining orifice means having cross-sectional areas in a ratio equal to the weighting of the respective binary signals in the binary code; and means for rendering the pressure at the flow determining orifice means of each valve element in the open state insensitive to variations in the second pressure.

Claim 14

A digital fluid flow control system comprising: a source of fluid at a first pressure; a fluid receiver at a second pressure lower than the first pressure; means for sensing the dynamic fluid conditions in the system; means responsive to the sensing means for generating a plurality of binary signals; a plurality of digital valve elements, each valve element having a fluid flow passage interconnecting the source to the receiver, flow determining orifice means in the passage, and means responsive to one of the binary signals for placing the valve element exclusively in an open state in which fluid flows through the passage or a closed state in which no fluid flows through the passage, the flow determining orifice means having cross-sectional areas in a ratio equal to the weighting of the respective binary signals in the binary code; and means for rendering the pressure at the flow determining orifice means of each valve element in the open state insensitive to variations in the second pressure.

Claim 15

The system of claim 11, in which the flow determining orifice means of each digital valve element comprises the throat of a converging-diverging nozzle located in the passage and the rendering means comprise the converging and diverging portions of the nozzle.

Claim 16

The system of claim 12, in which the fluid is compressible and the difference between the first and second pressures is sufficiently high for flow at sonic velocity through the throat of the converging-diverging nozzle.

Claim 17

The system of claim 12, in which the fluid of the source is liquid and the difference between the first and second pressures is sufficiently high to maintain the gas phase of the fluid at the throat of the converging-diverging nozzle.

Claim 18

The system of claim 11, in which the cross-sectional areas of the flow determining orifice means of at least some of the valve elements vary in accordance with a geometric progression of two.

Claim 19

The system of claim 11, in which the cross-sectional area of the flow determining orifice means of each valve element is smaller than the cross-sectional area of the remainder of the flow passage of such valve element.

Claim 20

A digital fluid flow control system comprising: a source of fluid at a first pressure; a fluid receiver at a second pressure lower than the first pressure; and a plurality of individually actuatable, digital valve elements each having a fluid flow passage interconnecting the source to the receiver, a converging-diverging nozzle having a throat with a flow determining cross-sectional area in the flow passage, a bistable plug disposed in the flow passage, a stationary cage formed in the passage, the cage having a perforated side connecting the interior of the cage with the source and an open end connecting the interior of the cage with the receiver, the converging-diverging nozzle of each digital valve element being located at the open end of the cage, and means for positioning the plug exclusively in an open position or a closed position, the plug covering the cage to prevent fluid flow through the passage in the closed position and uncovering the cage to permit fluid flow through the passage in the open position, the flow determining cross-sectional areas of at least some of the valve elements varying from one another; the minimum difference between the first and second pressures being sufficiently high to render the pressure at the throats of the nozzles of the valve elements having open plugs independent of the second pressure.

Claim 21

A digital fluid flow control system comprising: a source of fluid at a first pressure; a fluid receiver at a second pressure lower than the first pressure; and a plurality of individually actuatable, digital valve elements each having a fluid flow passage interconnecting the source to the receiver, a converging-diverging nozzle having a throat with a flow determining cross-sectional area in the flow passage, a bistable plug disposed in the flow passage, a stationary cage formed in the passage, the cage having a perforated side connecting the interior of the cage with the source and an open end connecting the interior of the cage with the receiver, the converging-diverging nozzle of each digital valve element being located at the open end of the cage, and means for positioning the plug exclusively in an open position or a closed position, the plug covering the cage to prevent fluid flow through the passage in the closed position and uncovering the cage to permit fluid flow through the passage in the open position, the flow determining cross-sectional areas of at least some of the valve elements varying from one another; the minimum difference between the first and second pressures being sufficiently high to render the pressure at the throats of the nozzles of the valve elements having open plugs independent of the second pressure.

Claim 22

The system of claim 17, in which the fluid is compressible, the difference between the first and second pressures is sufficiently high to maintain fluid flow at sonic velocity through the throat of the converging-diverging nozzle, and the nozzles are long enough to contain the resulting shock waves when their respective plugs are in the open state for the maximum difference between the first and second pressures.

Claim 23

The system of claim 17, in which the fluid is a liquid and the difference between the first and second pressures is sufficiently high to maintain the gas phase of the fluid at the throat of the converging-diverging nozzle.

Claim 24

The system of claim 17, in which the flow determining cross-sectional areas of at least some of the valve elements vary in accordance with a geometric progression of two.

Claim 25

A digital fluid control system comprising: a valve body having an upstream fluid manifold connected in the system, a downstream fluid manifold connected in the system, and a plurality of fluid flow passages interconnecting the upstream manifold to the downstream manifold; and a plurality of individually actuatable, digital valve elements in the respective flow passages each having a converging-diverging nozzle formed in the flow passage with a throat of a given cross-sectional area, a bistable plug in the passage, a stationary cage formed in the passage, the cage having a perforated side connecting the interior of the cage with one of the manifolds and an open end connecting the interior of the cage with the other manifold, the converging-diverging nozzle being located at the open end of the cage, and means responsive to a binary signal for positioning the plug exclusively to uncover the cage so fluid flow through the passage is permitted or to cover the cage so fluid flow through the passage is prevented; the sum of the given cross-sectional areas of the throats of the nozzles being sufficiently small relative to the system in which the manifolds are connected so the pressure difference between the upstream and downstream manifolds when the plugs of all the valve elements are in the open state is high enough to render the pressure at the throats of the nozzles of the valve elements in the open state insensitive to variations in the pressure in the downstream manifold.

Claim 26

A digital fluid control system comprising: a valve body having an upstream fluid manifold connected in the system, a downstream fluid manifold connected in the system, and a plurality of fluid flow passages interconnecting the upstream manifold to the downstream manifold; and a plurality of individually actuatable, digital valve elements in the respective flow passages each having a converging-diverging nozzle formed in the flow passage with a throat of a given cross-sectional area, a bistable plug in the passage, a stationary cage formed in the passage, the cage having a perforated side connecting the interior of the cage with one of the manifolds and an open end connecting the interior of the cage with the other manifold, the converging-diverging nozzle being located at the open end of the cage, and means responsive to a binary signal for positioning the plug exclusively to uncover the cage so fluid flow through the passage is permitted or to cover the cage so fluid flow through the passage is prevented; the sum of the given cross-sectional areas of the throats of the nozzles being sufficiently small relative to the system in which the manifolds are connected so the pressure difference between the upstream and downstream manifolds when the plugs of all the valve elements are in the open state is high enough to render the pressure at the throats of the nozzles of the valve elements in the open state insensitive to variations in the pressure in the downstream manifold.

Claim 27

The system of claim 21, in which the cross-sectional areas of at least some of the flow restrictive orifice means follow a geometric progression.

Claim 28

The system of claim 21, in which the cross-sectional areas of the remainder of the flow passages are identical to each other.

Claim 29

A flow control system comprising: (a) a gas receiver, (b) a source of gas under predetermined pressure, (c) a first conduit connecting said source and said receiver, (d) a first flow control valve in said conduit, (e) means including a first restricted orifice in said conduit, said orifice being of a size to produce gas flow therethrough, from said predetermined pressure, at or above sonic velocity whereby to insure a fixed rate of mass flow of said gas under said predetermined pressure, (f) a second conduit connecting said source and said receiver; (g) a second flow control valve in said second conduit, (h) means including a second restricted orifice in said second conduit, said second orifice being of a size to produce gas flow therethrough, from said predetermined pressure, at or above sonic velocity whereby to insure a fixed mass flow of said gas under said predetermined pressure, (i) means for selectively actuating said first valve and said second valve individually and together; (j) means for controlling said actuating means in response to pressure in said receiver.

Claim 30

A flow control system comprising: (a) a gas receiver, (b) a source of gas under predetermined pressure, (c) a first conduit connecting said source and said receiver, (d) a first flow control valve in said conduit, (e) means including a first restricted orifice in said conduit, said orifice being of a size to produce gas flow therethrough, from said predetermined pressure, at or above sonic velocity whereby to insure a fixed rate of mass flow of said gas under said predetermined pressure, (f) a second conduit connecting said source and said receiver; (g) a second flow control valve in said second conduit, (h) means including a second restricted orifice in said second conduit, said second orifice being of a size to produce gas flow therethrough, from said predetermined pressure, at or above sonic velocity whereby to insure a fixed mass flow of said gas under said predetermined pressure, (i) means for selectively actuating said first valve and said second valve individually and together; (j) means for controlling said actuating means in response to pressure in said receiver.

Claim 31

A system as in claim 24, in which said second orifice has an effective opening bearing a selected digital ratio to the effective opening of said first orifice.

Claim 32

A system as in claim 25, in which said ratio is 2 to 1.

Claim 33

A system as in claim 24, including at least one additional conduit connected between said source and said receiver and provided with an additional flow control valve and with an additional restricted orifice, the effective area of said additional orifice bearing the same ratio of the area of said second orifice as the area of said second orifice bears to the area of said first orifice.

Claim 34

A digital fluid flow control system comprising: a source of fluid at a first pressure; a fluid receiver at a second pressure lower than the first pressure; a plurality of individually actuatable, digital valve elements each having a fluid flow passage interconnecting the source to the receiver, a converging-diverging nozzle having a throat with a flow determining cross-sectional area in the flow passage, a bistable plug disposed in the flow passage, and means for positioning the plug exclusively in an open position or a closed position, the plug preventing fluid flow through the passage in the closed position and permitting fluid flow through the passage in the open position, the flow determining cross-sectional areas of at least some of the valve elements varying from one another; the minimum difference between the first and second pressures being sufficiently high to render the pressure at the throats of the nozzles of the valve elements having open plugs independent of the second pressure; means for sensing the dynamic conditions of the fluid in one of the manifolds; and means responsive to the sensing means for generating binary electrical signals for positioning the plugs of the valve elements.

Claim 35

A digital fluid flow control system comprising: a source of fluid at a first pressure; a fluid receiver at a second pressure lower than the first pressure; a plurality of individually actuatable, digital valve elements each having a fluid flow passage interconnecting the source to the receiver, a converging-diverging nozzle having a throat with a flow determining cross-sectional area in the flow passage, a bistable plug disposed in the flow passage, and means for positioning the plug exclusively in an open position or a closed position, the plug preventing fluid flow through the passage in the closed position and permitting fluid flow through the passage in the open position, the flow determining cross-sectional areas of at least some of the valve elements varying from one another; the minimum difference between the first and second pressures being sufficiently high to render the pressure at the throats of the nozzles of the valve elements having open plugs independent of the second pressure; means for sensing the dynamic conditions of the fluid in one of the manifolds; and means responsive to the sensing means for generating binary electrical signals for positioning the plugs of the valve elements.

Claim 36

A digital fluid control system comprising: a valve body having an upstream fluid manifold connected in the system, a downstream fluid manifold connected in the system, and a plurality of fluid flow passages interconnecting the upstream manifold to the downstream manifold; p1 a plurality of individually actuatable, digital valve elements in the respective flow passages each having a converging-diverging nozzle formed in the flow passage with a throat of a given cross-sectional area, a bistable plug in the passage, and means responsive to a binary signal for positioning the plug exclusively in an open state in which fluid flow through the passage is permitted or a closed state in which fluid flow through the passage is prevented; the sum of the given cross-sectional areas of the throats of the nozzles being sufficiently small relative to the system in which the manifolds are connected to the pressure difference between the upstream and downstream manifolds when the plugs of all of the valve elements are in the open state is high enough to render the pressure at the throats of the nozzles of the valve elements in the open state insensitive to variations in the pressure in the downstream manifold; means for sensing the dynamic conditions of the fluid in one of the manifolds; and means responsive to the sensing means for generating the binary electrical signals for positioning the plugs of the valve elements.

Claim 37

A digital fluid control system comprising: a valve body having an upstream fluid manifold connected in the system, a downstream fluid manifold connected in the system, and a plurality of fluid flow passages interconnecting the upstream manifold to the downstream manifold; p1 a plurality of individually actuatable, digital valve elements in the respective flow passages each having a converging-diverging nozzle formed in the flow passage with a throat of a given cross-sectional area, a bistable plug in the passage, and means responsive to a binary signal for positioning the plug exclusively in an open state in which fluid flow through the passage is permitted or a closed state in which fluid flow through the passage is prevented; the sum of the given cross-sectional areas of the throats of the nozzles being sufficiently small relative to the system in which the manifolds are connected to the pressure difference between the upstream and downstream manifolds when the plugs of all of the valve elements are in the open state is high enough to render the pressure at the throats of the nozzles of the valve elements in the open state insensitive to variations in the pressure in the downstream manifold; means for sensing the dynamic conditions of the fluid in one of the manifolds; and means responsive to the sensing means for generating the binary electrical signals for positioning the plugs of the valve elements.