NEEDLE / THROTTLING VALVES
NEEDLE / THROTTLING VALVES
NEEDLE VALVES / THROTTLING VALVES
| Straight needle valves are manual valves intended for
continuous throttling to achieve flow regulation. Valves are fitted in circuits
to allow the flow to be adjusted to suit variable operating conditions. Straight
needle valves are also used in instrument impulse lines to attenuate pressure
pulsations to limit gauge reading fluctuations. These “ meter ” valves are of a
more robust construction. Some valves have accurate calibration, micrometer
style scales, to permit repeatability. Some needle valves are not recommended
for isolation purposes, so product specifications must be checked carefully.
Like globe valves there is a preferred direction of flow: fluid enters the
bottom of the seat, travels up the taper and exits from the top.
The stem of a needle valve is machined to an accurate taper and small valves can have a very sharp point on the end. The seat, a much longer seat than in other valves, is machined to the same taper.
On opening, the valve creates a long narrow parallel flow passage. As the stem is withdrawn the flow passage enlarges and reduces the flow losses. Straight needle valves impose high losses in a circuit and have low C, values compared to other valve types. The nature of the flow passage excludes solids handling, and clean fluids are essential for acceptable component lives.
Needle value, optional with 30º poppet, V-notch, or rectangular slot. The form of the throttle opening influences the fineness of the flow setting , which is dependent on the pressure and viscosity. The needle is made of stainless steel and corresponds to a ring gap in the valve body. The body can be steel or brass as well as for pipe line or for panel mounting.
MANIFOLDS (2 way / 3 Way / 5 Way)
2-valve manifold finds its applications in pressure instruments such as pressure gauges, pressure transmitters and pressure switches and others.
3 valve and 5 valve Manifold are ideal for applications in differential pressure instruments such as differential pressure transmitters, differential pressure switches, differential pressure gauges, etc. 3-Valve Manifold, the most commonly used manifolds, could be provided with test ports on the process side and drain ports on the instrument side for draining of the process and instrument lines respectively.
5-Valve Manifold is suitable for applications with differential pressure instruments where drain valves are required on the instrument side. Further, they are used for flushing of the system and for prevention of loss of expensive fluid in the impulses.
"VIRGIN" makes Manifold Valves which are installed to measure, control, isolate, equalize, calibrate, drain, vent or differentiate the pressure of liquids & gases. We offer 2,3,5 valve manifold configuring remote mounting (pipe to pipe), direct mounting (pipe to flange T type & flange to flange H type) or panel mounting on to gauges, pressure switches or DP transmitters having 54 mm centre .
Two Valve Manifolds
Two Valve Manifold combines isolating, calibrating and
venting functions in a single neat unit and is ideal for use on Pressure Gauges,
Pressure Switches, Pressure Transmitters, Pressure Controllers and other
Pressure Sensitive instruments.
Used in conjunction with D/P transmitters, valve manifold is
a compact design instrument isolation valves high & low valves and
valves in one block.
Direct mounting 'H' type manifolds is ideal for stacked assembly between the instrument and the flange process connection. Co-planar manifolds are designed for direct mounting on to the instrument which help eliminates the adapter plate.
‘T’ type manifolds are designed for direct mounting on the instrument and are connected with screwed process connections.
Remote Mounted from the transmitter
SAFETY / PRESSURE RELIEF VALVES THERMAL RELIEF VALVE ATMOSPHERIC RELIEF VALVE PRESSURE REDUCING VALVES / STATION PRESSURE CUM VACUUM RELIEF VALVES BREATHER VALVES EXCESS FLOW CHECK VALVES EXCESS FLOW SHUT OFF VALVES UNDERGROUND SAFETY VALVES FOR WATER TANK / WATER FLOW CANAL AS PER BS – 4558 : 1983 NON – RETURN VALVES BALL VALVES DIAPHRAGM VALVES FLUSH BOTTOM VALVES