Abstract: In a digital fluid flow control system having a source of fluid at a first pressure and a fluid receiver at a second pressure lower than the first pressure, individually actuatable, digital valve elements interconnect the source to the receiver. In the flow passage of each valve element, there is an isolating orifice at which the pressure is independent of variations in the second pressure, by virtue of the difference between the first and second pressures. The isolating orifice of each valve element is preferably the throat of a converging-diverging nozzle that feeds into the receiver. In one implementation, spaced axially aligned upstream and downstream conduits are formed in a valve body; radial passages in which digital valve elements are located interconnect the conduits.

Abstract: A core removably fits into an open cavity with an outer casing. The walls of the cavity and the core define an upstream manifold, a downstream manifold, and a planar manifold separating partition that lies at an acute angle to a flow plane aligned with the inlet to the upstream manifold and the outlet from the downstream manifold. A plurality of individually actuatable bistable valve elements are individually mounted onto the core without threaded bore connections in a parallel arrangement to connect the upstream and downstream manifolds across the partition. Preferably, the bistable valve elements each have a double cage between which a plug is guided from an open position to a closed position.

Abstract: In a digital fluid flow control system having a source of fluid at a first pressure and a fluid receiver at a second pressure lower than the first pressure, individually actuatable, digital valve elements interconnect the source to the receiver. In the flow passage of each valve element, there is an isolating orifice at which the pressure is independent of variations in the second pressure, by virtue of the difference between the first and second pressures. The isolating orifice of each valve element is preferably the throat of a converging-diverging nozzle that feeds into the receiver. In one implementation, spaced axially aligned upstream and downstream conduits are formed in a valve body; radial passages in which digital valve elements are located interconnect the conduits.

Abstract: A plurality of individually actuatable, value weighted digital bistable valve elements in parallel interconnect a fluid source to a fluid receiver. A linear relationship is preferably maintained between the resultant fluid flow rate from the source to the receiver and the product of a flow rate determinative fluid parameter times the sum of the weighted values of the digital valve elements in the open state. The fluid parameter is sensed, the states of the digital valve elements are controlled, and a flow rate representative signal is derived from the states of the valve elements and the fluid parameter. If the fluid is liquid, the parameter is the square root of the pressure difference across the valve elements, in the absence of cavitating venturis, and is the square root of the difference between the upstream pressure and the vapor pressure of the liquid in the presence of cavitating venturis. If the fluid is gas, the parameter is the source pressure divided by the square root of the source temperature.