Hydraulic valves for dampening pressure spikes and associated methods are disclosed herein. In one embodiment, a hydraulic valve for dampening pressure spikes includes: a spool configured to move axially inside the hydraulic valve; and a sleeve configured to at least partially house the spool. A location of the spool with respect to the sleeve may determine a flow of a working fluid through the hydraulic valve. A viscous damper is at least partially housed inside an opening in the spool, and a viscous friction between the viscous damper and the opening in the spool slows a motion of the spool.

A retarder control valve assembly and system for controlling speed of rail cars, utilizes cartridge valves carried in a manifold body including piping and pilot control apparatus, but no wearing surfaces, dynamic seals, or moving parts. The cartridge valves are replaceable without replumbing, and include all moving valve elements and dynamic seals. The valves each include a piston controlled poppet carried on a spool movable within a cartridge body to open and close the valve and supported to withstand high side loads. The pressure sensing and feedback to the retarder system controller is at the manifold, in a pressure spike attenuating circuit having a phase modulating capability to mimic retarder pressure remotely.

Disclosed is a flow control valve for construction machinery, the flow control valve being adapted to reduce pressure loss due to flow on return to a hydraulic tank during the boom-down operation of a large-scale excavator. The flow control valve for construction machinery according to the present invention comprises: first and second boom spools which are respectively coupled to first and second boom valve blocks, and which regulate working fluid that is respectively supplied from first and second hydraulic pumps to a boom cylinder during direction reversal; a boom-up flow-adjusting means which, in direction reversal of the first and second boom spools for boom-up drive, supplies working fluid from the first and second hydraulic pumps into a large chamber of the boom cylinder via the first and second boom spools respectively, and causes part of the flow of working fluid from the second hydraulic pump to pass via the second boom spool so as to be combined with working fluid being supplied from the first hydraulic pump to the large chamber of the boom cylinder due to direction reversal of the first boom spool; and a boom-down flow-adjusting means which, in direction reversal of the first and second boom spools for boom-down drive, causes part of the flow of working fluid coming back from the large chamber of the boom cylinder to return to the hydraulic tank via the first and second boom spools respectively, and causes part of the flow of working fluid coming back from the large chamber of the boom cylinder to combine as respective regenerative flows for working fluid on the small chamber side of the boom cylinder.

A manual override assembly for a hydraulic power source operates to override an actuator of a hydraulic power source. The assembly includes a lever arm and connecting rods. The lever arm pivotally moves relative to a valve body of the hydraulic power source. The lever arm is connected to valve spools via the connecting rods, respectively. Each spool has a bore with an off-set opening for inserting one end of the connecting rod.

A bleed valve control system for mounting to a support structure adjacent to a fan air plenum within an aircraft includes a bleed valve module, a pneumatic valve controller, and a fan air duct. The bleed valve module includes a pipe, a plurality of bleed valves connected to the pipe, and a plurality of pneumatic actuators connected to the bleed valves. The pneumatic valve controller includes a plurality of electrical control elements and a cooling shroud. The cooling shroud is attached to the pipe and at least partially surrounds the plurality of electrical control elements. The fan air duct connects the cooling shroud to the fan air plenum such that fan air flows through the cooling shroud to cool the plurality of electrical control elements.

A compressed air supply installation for operating a pneumatic installation, especially an air suspension installation of a vehicle, includes a compressed air supply unit, a compressed air port towards the pneumatic installation, a venting port towards the surroundings, a first pneumatic connection between the compressed air supply and the compressed air port, the first pneumatic connection having an air drier and a shut-off valve, and a second pneumatic connection between the compressed air port and the venting port. The shut-off valve is a pneumatically pilot-controlled check valve.

A minimum pressure shut-off valve closes off fuel flow responsive fuel pressure being below a predefined pressure. A sleeve includes at least a first flow window and a second flow window. The second window includes a notch providing a flow area based on an axial position of a spool moveable within the sleeve.

Hydraulic valves for dampening pressure spikes and associated methods are disclosed herein. In one embodiment, a hydraulic valve for dampening pressure spikes includes: a spool configured to move axially inside the hydraulic valve; and a sleeve configured to at least partially house the spool. A location of the spool with respect to the sleeve may determine a flow of a working fluid through the hydraulic valve. A viscous damper is at least partially housed inside an opening in the spool, and a viscous friction between the viscous damper and the opening in the spool slows a motion of the spool.

A manual override assembly for a hydraulic power source operates to override an actuator of a hydraulic power source. The assembly includes a lever arm and connecting rods. The lever arm pivotally moves relative to a valve body of the hydraulic power source. The lever arm is connected to valve spools via the connecting rods, respectively. Each spool has a bore with an off-set opening for inserting one end of the connecting rod.

A manual override assembly for a hydraulic power source operates to override an actuator of a hydraulic power source. The assembly includes a lever arm and connecting rods. The lever arm pivotally moves relative to a valve body of the hydraulic power source. The lever arm is connected to valve spools via the connecting rods, respectively. Each spool has a bore with an off-set opening for inserting one end of the connecting rod.