Needle Valves have a small port and a threaded, needle-shaped plunger allowing precise regulation of flow, although it is generally only capable of relatively low flow rates. It uses a tapered pin to gradually open a space for a fine control of flow. The flow can be controlled and regulated with the use of a spindle.
- A needle valve has a relatively small orifice with a long, tapered seat, and a needle-shaped plunger on the end of a screw, which exactly fits the seat.
- As the screw is turned and the plunger retracted, flow between the seat and the plunger is possible.
- However, until the plunger is completely retracted, the fluid flow is significantly impeded.
Since it takes many turns of the fine-threaded screw to retract the plunger, precise regulation of the flow rate is possible with needle valves.
TRUPPLY brings to you a wide range of needle valves.
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Needle valve provides flow control wherever a small amount of fluid must be metered from a fluid system. The operation of needle valve requires many turns of the handle to open the valve all the way. This implies a high level of adjustment. Needle valves are often used in instrumentation panel to allow or restrict flow of fluid. It is also used before pressure gauge to check system pressure when needed. Small orifice of needle valve gives precise and slow flow control avoiding hammering effect to pressure gauges. Block and bleed needle valves have bleed port to purge trapped pressure.
Selection of needle valve require consideration of 4 main factors
- Pressure Rating
- Temperature Rating
- Valve Size
Needle valves are available in carbon steel, stainless steel and Brass. Pressure rating varies from 6,000 psi to 10,000 psi. Temperature rating varies with the material. Higher temperature may require use of PTFE or Peek as seal material. Needle valve is available in size 1/8" to 1" though more common sizes are 1/4" to 1".
Q&A with a Distributor
We recently sat down with a distributor which specializes in smaller size valves and pressure products (up to 4") mainly for O&G customers. Below is the transcript of the session;
Speaker 1: Ok, this a needle valve, I'm showing you here the stainless steel needle valve; however we do offer it in a carbon steel as well, same body style. We do offer the needle valve in a quarter-inch, male by male, male by female, female by female. We also offer the quarter-inch, half-inch, three quarter-inch and one-inch. There's different combinations of male by female, and we have female by female, male by male. So there's a variety of different ones on there. We do offer it in a 6,000 psi as well as a 10,000 psi. We do offer it - it does come with a T-bar handle. We do also offer some mini needle valves that go along with this line. The mini needle valves are 6,000 psi on all mini valves; we will offer a T-bar handle on the mini's as well as a round nob handle. We do also offer some angle valves as well, your a little bit more familiar with the angles valves do you remember the sizes on those?
Speaker 2: They're all half-inch.
Speaker 1: Half-inch on the angle valves?
Speaker 2: 10,000 pounds.
Speaker 1: Ok, so those are 360 stainless steel and carbon steel bodies