Abstract: A transducer assembly for measuring the pressure difference between first and second pressures comprises a differential pressure transducer and a valve coupled to the differential pressure transducer. The differential pressure transducer has a first pressure region and a second pressure region and generates an electrical signal in response to a pressure differential between the first and second pressure regions. The valve is arranged to connect the first and second pressure regions when the pressure differential exceeds a first value. One embodiment of the valve comprises a chamber and a poppet. The chamber has a first port, a second port, and a wall. The cross sectional flow area of the chamber is larger than the cross sectional flow area of the first or second port.

Abstract: A device for sensing fluid flow comprises a housing having an inlet and an outlet and defining a fluid flow channel between the inlet and the outlet, a first member disposed in the fluid flow channel and including at least one rigid portion, and a second member disposed in the fluid flow channel upstream from the first member and including at least one flexible portion, the flexible portion being elastically flexible between an initial position spaced from the rigid portion and defining a first effective flow area and a final position adjacent the rigid portion and defining a second effective flow area which exceeds the first effective flow area. The device includes pressure passages including a linking arrangement for conveying pressures to a pressure transducer from upstream and downstream of the second member, the pressure measurements being correlated to a fluid flow rate. The link arrangement protects the transducer from pressure surges. The pressure transducer may be disposed in the housing.

Abstract: The disclosure describes a filter assembly for removing particulates from a fluid. The filter assembly comprises a porous pleated composite and structure for directing fluid flow through the composite. The composite includes upstream and downstream filter media, the upstream filter medium being removably mounted on the surface of the downstream filter medium.

Abstract: The disclosed pressure transducer assembly comprises a transducer for generating electrical signals in response to differential pressures; a structure for encasing the transducer, the encasing structure including first and second ports for communicating fluids at first and second pressures to the transducer; and a housing for enveloping the casing structure with fluid having a pressure at least approximately equal to the first or second pressure, the encasing structure being removably disposed within the housing.

Abstract: An automatic bleed valve for bleeding air from a pressurized liquid reservoir or, with reversal of principal elements, bleeding liquid from a compressed gas reservoir comprises a piston in a piston chamber located in a flow passage leading from the reservoir. A capillary passage is provided through the piston, and the piston is urged upstream by a resilient spring. An orifice is located in the fluid channel. A sealing element is provided at the downstream end of the piston chamber. Upon activation of the hydraulic system while air is being expelled from the reservoir, the resilient spring will retain the piston in the upstream position, allowing gas to be bled from the reservoir through the fluid passage in the piston. When liquid begins to flow from the reservoir, the pressure differential over the piston increases, causing the piston to move against the downstream end of the piston chamber and seal off the fluid channel and the hydraulic reservoir.

Abstract: A filter assembly for removing particles from a fluid which comprises first and second filters, each having a porous filter medium. The mean pore diameter of the porous filter medium of the second filter is greater than the mean pore diameter of the porous filter medium of the first filter. The filter assembly further comprises structure for directing the fluid serially through the first filter and then through the second filter, a mechanism for sensing the temperature of the fluid, and a valve arranged in parallel with the first filter and serially with the second filter. The valve is coupled to the temperature-sensing mechanism so that at least a portion of the fluid is directed around the first filter in response to a predetermined fluid temperature. For example, in the illustrated embodiment, the fluid is directed around the first filter when the fluid temperature is below a predetermined value.

Abstract: A device is provided for determining the density or concentration of solid contaminants suspended in a fluid, having an orifice or narrow passage through which the fluid carrying suspended solid contaminants is passed, and monitoring the rate of build-up of the contaminants at the orifice or narrow passage as a function of the density or concentration of the contaminants in the fluid.

Abstract: A flow sensor is provided, responsive to fluid flows within a range from above a predetermined minimum to below a predetermined maximum, to indicate that flow is within that range and the minimum flow has been exceeded, but nonresponsive to fluid flows below the predetermind minimum or above the predetermined maximum, to avoid giving a false indication of fluid flow, comprising a flow-responsive valve and a differential pressure indicator.

Abstract: A flow sensor is provided responsive to fluid leakage flows within a range from above a predetermined minimum to below a predetermined maximum, to indicate that leakage flow is within that range and/or that maximum leakage flow has been exceeded, but nonresponsive to fluid flows below the predetermined minimum or above the predetermined maximum, to avoid giving a false indication of fluid leakage flow, comprising a flow responsive valve and a differential pressure indicator sensing differential pressure between fluid leakage flow and normal fluid flow at the valve.

Abstract: A magnetic differential pressure indicator is provided for detecting and indicating a pressure differential thereacross that is greater than a predetermined value in a fluid system, having a port that permits introduction or withdrawal of fluid for testing of operability under the predetermined pressure differential, and having a bimetallic element that prevents false actuation of the element at abnormal temperature, and a deactuator for the bimetallic element that permits such testing of the indicator via the port for operability even at such abnormal temperature.

Abstract: A magnetic differential pressure indicator is provided for detecting and indicating a pressure differential thereacross that is greater than a predetermined value in a fluid system. A thermal lockout effective even at high internal fluid pressures prevents false actuation of the magnetic indicating means at low temperatures due to increased viscosity of the system fluid.

Abstract: A magnetic differential pressure indicator is provided for detecting and indicating a pressure differential thereacross that is greater than a predetermined value in a fluid system. The sampling port permits withdrawal of fluid for examination without interference with operation of the indicator.