A freeze protection system is provided that includes a first valve configured to be coupled with an inlet of a water heater, such as a tankless water heater; a second valve configured to be coupled with an outlet of the water heater; and a valve actuator configured to automatically actuate the first valve and the second valve to permit water to drain from the water heater when (1) electric power is lost to the water heater, and (2) a temperature of a fluid in or around the water heater is less than or equal to a predetermined low temperature threshold.

Disclosed is a railway braking system including a control device having a valve with a body having a cavity and a slide having an internal chamber, supply notches and drainage notches each having an overall passage cross-section for a pressure medium having a shape exhibiting an apex, and being movably mounted in the cavity, between a supply position where the supply notch is opposite a supply groove of the body, and a drainage position where the drainage notch is opposite a drainage groove of the body; the device being configured to allow a substantially stable control configuration, wherein the pressure value of the medium is limited, and wherein the slide is positioned in the cavity such that a control notch of the slide is opposite a control groove of the body while the supply and drainage notches are respectively at a distance from the supply and drainage grooves.

A servo valve includes a fluid transfer valve assembly comprising a supply port and a control port; a valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a drive means configured to move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow. The drive means is arranged to rotate the spool relative to the fluid transfer assembly, the spool provided with openings arranged to selectively align with or block flow channels in the fluid transfer assembly according to the direction and degree of rotation of the spool.

A valve arrangement includes a housing arrangement (12), (18), a first spool valve (1a, 1b) having a first spool (3a, 3b) and a second spool valve (2a, 2b) having a second spool (4a, 4b), wherein the first spool valve (1a, 1b) and the second spool valve (2a, 2b) each includes a supply channel arrangement having a pump channel (5) and a tank channel (6), and a working port arrangement having two working ports (8, 9), wherein the spools (3a, 3b; 4a, 4b) control a flow path between the supply channel arrangement (5, 6) and the working port arrangements (7, 8). In such a valve arrangement, it should be possible to simply adapt the control behaviour to different purposes. To this end, the working port arrangement (7, 8) is arranged in a flange (16a, 16b) connected to the housing arrangement (13, 14; 19, 20).

A valve arrangement includes a housing arrangement (12), (18), a first spool valve (1a, 1b) having a first spool (3a, 3b) and a second spool valve (2a, 2b) having a second spool (4a, 4b), wherein the first spool valve (1a, 1b) and the second spool valve (2a, 2b) each includes a supply channel arrangement having a pump channel (5) and a tank channel (6), and a working port arrangement having two working ports (8, 9), wherein the spools (3a, 3b; 4a, 4b) control a flow path between the supply channel arrangement (5, 6) and the working port arrangements (7, 8). In such a valve arrangement, it should be possible to simply adapt the control behaviour to different purposes. To this end, the working port arrangement (7, 8) is arranged in a flange (16a, 16b) connected to the housing arrangement (13, 14; 19, 20).

A downhole tool control system for a drill string rotary steerable tool that includes a body having an inner chamber, a piston gallery extending between the inner chamber and a piston port, and an exhaust gallery extending between the inner chamber and an exhaust port. A spool in the inner chamber is movable into a plurality of positions to direct and control the timing and duration of the flow of drilling fluid to energize pistons of the rotary steerable tool, and to de-energize the pistons. The spool includes a first passage in fluid communication with a drilling fluid inlet port but not the exhaust port, and a second passage in fluid communication with the exhaust port but not the drilling fluid inlet port.

A three-way valve is disclosed. The valve achieved constant flow rate as the valve transitions from 100% flow through the first path to 100% flow through the second path. The valve is linearly actuated, which allows a plurality of valves to be efficiently disposed in a manifold. The valve comprises a spool having two passageways therethrough which converge at the input. The spool is disposed in a housing. By linear movement of the spool within the housing, the amount of the incoming flow that passes through each of the two passageways can be controlled. In certain embodiments, the spool is in communication with an actuator to control its position within the housing. The three-way valve may be used as part of a manifold.

A three-way valve is disclosed. The valve achieved constant flow rate as the valve transitions from 100% flow through the first path to 100% flow through the second path. The valve is linearly actuated, which allows a plurality of valves to be efficiently disposed in a manifold. The valve comprises a spool having two passageways therethrough which converge at the input. The spool is disposed in a housing. By linear movement of the spool within the housing, the amount of the incoming flow that passes through each of the two passageways can be controlled. In certain embodiments, the spool is in communication with an actuator to control its position within the housing. The three-way valve may be used as part of a manifold.

A guide frame for a four-way reversing valve is provided. The guide frame includes a frame body. Both ends of the frame body are provided with a connecting portion, respectively. The connecting portion includes a first bending member and a second bending member, and the directions of bending of the first bending member and of the second bending member are opposite. The connecting portion is provided with a reinforcing member. The reinforcing member includes a first reinforcing plate and a second reinforcing plate. The first reinforcing plate is connected to the outer side of the first bending member by welding, and the second reinforcing plate is connected to the outer side of the second bending member by welding. Optionally, the first reinforcing plate is connected to the inner side of the first bending member by welding and the second reinforcing plate is connected to the inner side of the second bending member by welding. The connection strength of the connecting portion is increased, such that the guide frame is less likely to deform or break.

A mounting aid device for mounting a valve slide in a housing bore of a valve housing of a slide valve includes a mounting slide arranged movably in a guide of a guide piece and protruding out of the guide of the guide piece on both sides. The guide piece includes a first stop, with which the guide piece is placeable coaxially to the housing bore when the guide piece contacts the valve housing at the first stop. The mounting slide configured to protrude into the housing bore until contact on the second end region of the valve slide and, by force-loading of the mounting slide under compression of the spring element, the valve slide is movable until the valve slide reaches the first end position.