There are many different designs of hydraulic control valves, including check, cartridge, directional, relief, safety, shut off and solenoid valves. Hydraulic control valves come in a variety of sizes and pressure ratings.
In an open position, hydraulic valves permit the flow of fluid; when in a closed position, they prevent flow. Hydraulic control valves are used to prevent improper levels of pressure and fluid in hydraulic systems. The basic mechanics of all hydraulic control valves essentially remains the same; each is usually cylindrical and occasionally contained in a small square-shaped house, placed at the mouth of a pipe or on the head of a pump and contains a seat in the opening that cradles the plunger that may be a variety of shapes and sizes.
These various styles are mass produced in general cavity sizes, as well as being specially designed for certain out of the ordinary applications. The size of a hydraulic valve may vary from a fraction of a millimeter to three or four meters long. Whatever size, they are able to control the flow of liquid, whether it is thick like oil or thin like water. Some valves simply shut off flow when flow rates get too high, while others transmit signals to other valves in order to provide a systematic balance of flow.
A wide range of styles crowds the hydraulic valve market, giving buyers plenty of specialized options. The hydraulic solenoid valve has a coil that is electrically activated when the flow of liquid changes in intensity, which then sends a signal to the plunger to cut off or release the flow. Proportional valves do a similar thing, by having an electric current alert the plunges when to stop or release, but is additionally able to control the output flow even while taking in more input flow.
For this reason, the hydraulic proportional valves, which are a major subcategory of control valves, are becoming more popular then solenoid valves on the market today. Another popular one in complex liquid systems is the directional control valve, which will direct the fluid to specific areas. Machines and devices that run on hydraulic power use hydraulic control valves. These valves are used in conjunction with hydraulic cylinders, pumps and motors. They are commonly found in those vehicles manufactured by the automotive, aviation, and construction industries.