Needle Valves

A needle valve is a fine-throttling valve in which a slender, tapered stem (the needle) advances into or withdraws from a small seat orifice. The long, gradual taper changes the flow area very gradually with each turn of the stem, giving precise control of small flows and pressures. Needle valves are not general isolation valves: their small port limits capacity, but for accurate low-flow regulation they are the standard choice.

The main applications are on instrument, gauge, sampling and calibration lines and as metering and bleed valves on hydraulic and pneumatic systems. They isolate and regulate the flow to pressure gauges and transmitters, take samples from a process line and set small bleed and purge flows. Angle-pattern and multi-port bodies, and manifold-mounted versions, support instrument hook-ups directly at the tapping point.

Bodies are typically forged in stainless steel, carbon steel, brass or exotic alloys for high-pressure and corrosive service, with compression, threaded or weld ends and packed or, where leakage is critical, packless bonnets. Pressure ratings are high relative to the small bore, and the tapered metal stem and seat give repeatable, erosion-resistant control. When specifying, provide the bore and connection, the working pressure and temperature, the medium and the body material, and we can propose a suitable valve for the duty.