Hydraulic Valves

Valves are used in Hydraulic systems as very high pressure hydraulic fluid to perform various functions.
Huge amounts of energy can be transferred over short distances much more efficiently with hydraulic systems than with electrical systems, especially when the desired motion is linear instead of rotational.
A basic hydraulic system will have a pump, a pressure control valve, one or more control valves, one or more pistons or hydraulic motors that transfer the hydraulic power into motion and a return system that collects the low-pressure hydraulic fluid and feeds it back to the pump for re-use.
This article focuses on the hydraulic control valve illustrated in below diagram.

Ball valves are quarter-turn, straight through flow valves that have a round closure element with matching rounded seats that permit uniform sealing stress.
Ball valves are used in situations where tight shut-off is required.
The type of seat can vary with the valve pressure rating and materials of construction.
Ball valves seats are composed of single molded forms, while other seats with higher-pressure ratings often incorporate a trunnion design where each face of the ball is separately sealed.
Ball valves are wide duty valves, able to transfer gases, liquids and liquids with suspended solids (slurries).
Ball valves offer many advantages when contrasted with other valve types.
Ball Valves can provide superior ease of operation and can maintain and regulate high volume, high pressure and high temperature flow.
Ball valves offer rugged construction providing for a long service life, and a comparably low cost.

Needle valves have a slender, tapered point at the end of the valve stem that is lowered through the seat to restrict or block flow.
Fluid flowing through the Needle valve turns 90 degrees and passes through an orifice that is the seat for a rod with a cone shaped tip.
Needle valves are widely used to accurately regulate the flow of liquids and gases at low flow rates.
The fine threading of the stem and the large seat area allow for precise resistance to flow.
Needle valves are used to control flow into delicate gauges,which might be damaged by sudden surges of fluid under pressure.

Throttle valve consists essentailly of a valve body, a special control spindle & the control know.
Throttle valve do not have in build check valve so direction of Flow of oil can be taken in both the way in the piping systems the control knob has coloured scale and each scale rings permits accurate repetition of the settings.
The size of the coloured triangle on the rings indicates the size of the flow area.
An increase in the size of the coloured triangle corresponds to an increase in flow area.
A set screw locks the settings.
Throttle valves allow the flow is controlled in both the directions.

Quick Links