76 results about "Double check valve" patented technology

An improved apparatus for monitoring the intra-abdominal pressure of a hospitalized patient includes a urinary catheter connected to a urine valve having selectable communication positions between a discharge end of the urinary catheter and either a drain or a fluid source. Preferably, the urine valve has a housing adapted to resist patient discomfort from leg-valve contact. One operable protective housing may be embodied as a separate tray component. Plumbing structure desirably maintains fluid supply and drain conduits in a substantially parallel arrangement to assist routing those conduits between a patient's legs. When the urine valve is oriented for communication to the fluid source, an infusion pump may be used to introduce a known quantity of fluid through the urine valve and into the patient's bladder where the fluid's pressure can be measured. Desirably, a double check valve is included in a fluid supply path and arranged to permit repetitive operation of a syringe to inject a bolus of fluid into the patient's bladder. Subsequent to making a pressure measurement, the urine valve is returned to the bladder draining position.

A double check valve that generally includes a modular fluid casing having a main housing, a one-piece modular cage, and at least one in-line check valve removably housed in the modular cage.

A tractor protection valve includes a trailer service brake portion, a trailer parking brake portion, and a stability control portion that are each formed within a common valve body. In one example, the trailer service brake portion includes three inlets that can be used to apply a trailer service brake. The three inlets cooperate with a service brake blocking piston, a service brake relay piston, and double check valves to apply the trailer service brakes as needed. The stability control portion includes a solenoid that can direct air to apply the trailer service brakes in response to a stability control signal. The trailer parking brake portion also includes multiple ports that cooperate with a parking brake piston and valve to control application and release of the trailer parking brakes.

The invention provides a self-balanced underground full-bore check valve which comprises a first connector (10), a second connector (20), a switch valve (30) and a sliding sleeve (40), wherein the switch valve (30) comprises a valve seat (31) and a valve sheet (32); a first seal cavity (211) communicated with a space in a pipe and a second seal cavity (212) communicated with a space outside the pipe are respectively defined by the sliding sleeve (40) together with the first connector (10), the second connector (20) and the switch valve (30); and the valve sheet (32) is provided with a first working state of closing a valve port when the external pressure of an operating pipe column is greater than the internal pressure of the operating pipe column and a second working state of opening the valve port when the internal pressure of the operating pipe column is greater than or equal to the external pressure of the operating pipe column. The self-balanced underground full-bore check valve provided by the invention can be automatically opened or closed in time according to the real-time change of the internal and external pressure difference of the pipe column, thereby preventing blowout accidents from happening, improving the production safety, shortening the operation time and lowering the operation cost.

A valve (10) comprising a housing (12) formed with a downstream port (14) and an upstream port (28), with an axially displaceable plunger (34) biased into sealing engagement of a major flow path (78) extending between the downstream port (14) and the upstream port (28) for admitting flow only in the upstream direction. The plunger is formed with a normally closed minor flow path (86) for admitting flow only in a downstream direction.

A vehicle brake system includes a source of fluid pressure adapted to supply a braking force a brake actuator including a parking brake chamber, and a combination valve fluidly coupling the brake actuator to the source of pressure, the combination valve having an inlet fluidly coupled to the source of pressure and an outlet fluidly coupled to the brake actuator. The combination valve includes within a single housing (i) a solenoid responsive to electrical signals to move from one position in which the parking brake chamber is fluidly coupled to the source of pressure in order to pressurize the parking brake chamber and release the parking brake, and another position in which the parking brake chamber of the brake actuator is vented in order to exhaust pressure within the parking brake chamber so that the parking brake is applied, and (ii) at least one of a manifold, an inversion valve, a double check valve and an anti-compounding valve.

A hydraulic circuit having a holding valve of an external pilot pressure operation type is provided, which can make a double check valve, which is installed to prevent an actuator from being pushed due to leakage of hydraulic fluid of a main control valve, be opened by an external signal pressure being supplied to shift the main control valve. The hydraulic circuit includes a hydraulic pump connected to an engine and a pilot pump, a hydraulic cylinder connected to the hydraulic pump to expand and contract when hydraulic fluid is supplied thereto, a main control valve installed in a flow path between the hydraulic pump and the hydraulic cylinder and shifted to control a start, a stop, and a direction change of the hydraulic cylinder, a joystick outputting a pilot signal pressure from the pilot pump in accordance with an amount of user's manipulation thereof, a double check valve installed in a flow path between the main control valve and the hydraulic cylinder to be opened by the pilot signal pressure for shifting the main control valve, and preventing the hydraulic cylinder from being moved due to leakage of hydraulic fluid of the main control valve, and a select valve shifted to open the double check valve in response to the pilot signal pressure being supplied in accordance with the manipulation of the joystick.

A double check valve is integrally located in a spring brake chamber to reduce plumbing associated with a pneumatic brake system. Anti-compounding is provided by virtue of a bias pressure of approximately twenty to thirty psi between a pressure chamber of a service actuator and an operating chamber of a parking/emergency actuator. Likewise, vehicle roll-back is addressed since the transition from a service application to a park application assures that the service brakes are sufficiently applied until the spring brake becomes operative.

A parking brake reset system for a railway vehicle, such as a transit vehicle, includes a brake operating unit fluidly connected to a main air reservoir and controlling air flow to a brake cylinder of the railway vehicle, a brake pipe, a parking brake, and a control valve in line between the brake pipe and the parking brake to establish fluid communication between the brake pipe and the parking brake. The control valve is in line between the brake operating unit and the parking brake, whereby the control valve controls air flow to the parking brake from the main air reservoir and the brake pipe. The control valve may be a double check valve or a 3-way cutout valve, as examples.

A brake system that uses a quick release valve in place of a double check valve to optimize the timing of the release of pressurized air from the brake chambers and supply lines is provided. The quick-release valve further includes a threaded exhaust port that functions as a second supply port. By using the threaded exhaust port as a second supply port, the diaphragm in the quick release valve acts similar to an unbiased diaphragm double check valve during periods of increasing air pressure, but retains the functionality of a quick release valve during periods of decreasing air pressure by favoring release through the threaded exhaust port.

A double check valve having a floating function is disclosed, which can prevent construction equipment from overturning through intercepting of a floating function even if a signal pressure is fed to the double check valve to perform the floating function in a state that an excavator is supported by a working device (e.g. a dozer blade), i.e. in a jack-up state, on a sloping site and so on. The double check valve includes a hydraulic pump; a hydraulic cylinder connected to the hydraulic pump to operate a working device; a control valve installed in flow paths between the hydraulic pump and the hydraulic cylinder, and shifted to control a start, a stop, and a direction change of the hydraulic cylinder; and a double check valve installed in flow paths between the control valve and the hydraulic cylinder, and including a pair of plungers having first diaphragms formed thereon to receive an operating pressure being applied to the hydraulic cylinder and second diaphragms formed thereon to receive a signal pressure being applied to the signal pressure flow path, and a pair of check valves being pressed to remove their check function through shifting of the plungers. Sectional areas of the first diaphragms and the second diaphragms are different from each other.

The invention discloses a parking brake control unit with a remote relieving function. The parking brake control unit comprises a first cock which is arranged on a pipeline and used for being communicated with a main air pipe, a second cock used for being communicated with a brake pipe and a third cock used for being communicated with an average pipe, and the parking brake unit further comprises a pulse solenoid valve used for being communicated with a parking brake cylinder; the first cock and the second cock are communicated with the pulse solenoid valve separately; the parking brake unit further comprises a first double check valve which has a first end, a second end and a third end, the first end of the first double check valve is communicated with the pulse solenoid valve, the second end of the first double check valve is communicated with the portion, between the second cock and the pulse solenoid valve, of the pipeline, the first end of the first double check valve and the second end of the first double check valve are not conductive, the first end of the first double check valve and the third end of the first double check valve are conductive, and the second end of the first double check valve and the third end of the first double check valve are conductive.

The invention relates to a large-flux magnetic check valve, with high reliability, high flux and low cost, etc, for overcoming the defects of single-layer check valve as low reliability and high resistance. Wherein, said check valve mounts multilayer valve in one cylinder valve body, which are formed by serially connected two-sheet valve and curve valve, or only by connected two-sheet valves or curve valves; the two-sheet valve has two valves that symmetry switched; the curve valve has one sheet of curve valve, that switch around the axle at 90 degree; the switch of valve depends the magnetic force of permanent magnet, without auxiliary closed return spring; when the valve is at maximum opening, the fluid can pass through in straight line.

A brake control device includes: a relay valve that generates a first drive pressure for driving a brake, from an air pressure generated by a first air supply source, based on an pilot pressure applied; a double check valve that connects the relay valve and a second air supply source that generates a second drive pressure separate to the first air supply source, and that communicates the drive pressure which is generated in either the relay valve or the second air supply source, with the brake; a variable load valve that outputs a first pressure according to a pressure of an air spring fitted on a vehicle side; a first solenoid valve group which generates the pilot pressure from the air pressure during service operation; and a second solenoid valve group which outputs, as the pilot pressure, a second pressure according to the first pressure output from the variable load valve during emergency operation.

A valve proportioning assembly that incorporates a check valve assembly is improved in manufacture and assembly. The valve proportioning assembly includes a housing having a blind opening that receives a sub-assembly of two separate non-metallic components that mate via an interference fit or snap-fit together enclose the check valve assembly. The non-metallic components enclose the check valve assembly. It includes a spring and spring follower so that a sub-assembly is formed for insertion into a blind bore. This minimizes potential misassembly, provides for a wider array of design configurations, and offers the additional advantage of adding more complete informational indicia directly into the molded components.