Home ยป How Needle Valve Works ?
Control Valves

How Needle Valve Works ?

Needle valves are designed to allow precise flow control. Its name is derived from the sharp pointed disc and matching seat. They are extensively used for continuous blow-off or chemical feed control services.

The stem threads are finer than usual so that considerable movement of the hand wheel is required to increase or decrease the opening through the seat. Usually, these valves have a reduced seat diameter in relation to the pipe size.

Needle valves Images

Needle Valve Works

A variation on the stem-guided globe valve design is the needle valve, where the plug is extremely small in diameter and usually fits well into the seat hole rather than merely sitting on top of it.

Needle Valve Schematic

Needle valves are very common as manually-actuated valves used to control low flow rates of air or oil.

A set of three photographs shows a needle valve in the fully-closed, mid-open, and fully-open positions (left-to-right):

Needle Valve Pictures

Uses of Needle Valve

Needle valves are usually used in flow-metering applications, especially when a constant, calibrated, low flow rate must be maintained.

Since flow rates are low and many turns of the valve stem are required to completely open or close, needle valves are not used for simple shutoff applications.

Since the orifice is small and the force advantage of the fine-threaded stem is high, needle valves are usually easy to shut off completely, with merely “finger-tight” pressure. The spindle and/or seat of a needle valve, especially one made from brass, are easily damaged by excessive turning force when shutting off the flow.

Articles You May Like :

Valve Seat Leakage Test

What is Lift Check Valve ?

What is Port-guided Globe Valve ?

Control Valve Working Animation

Control Valve Performance

Related Articles

Pneumatic Valves Questions & Answers

S Bharadwaj Reddy

What is a 4-way Solenoid Valve ?

S Bharadwaj Reddy

Self Actuated Pressure Control Valve Functional Testing

S Bharadwaj Reddy

Effect of Differential Pressure on Control Valve Lift

S Bharadwaj Reddy

What is Swing Check Valve ?

S Bharadwaj Reddy

Valves Pressure Loss – Questions and Answers

S Bharadwaj Reddy

Leave a Comment

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More

How Needle Valve Works ?

WordPress Image Lightbox

Send this to a friend