Needle Valves

Frequently Asked Questions (FAQs)

Q: What is a PTFE needle valve used for?
A: For precise regulation of corrosive gases and liquids in lab and industrial systems, including high purity service. VT valves may also be used as shut off in pressure or non critical vacuum applications. Bubble tight shutoff is specified for PTFE metering valves, not VT.

Q: What are the operating limits and flow ranges?
A: ted to 75 psig and 150 °F. Flow spans from 2,400 mL/min air and 130 mL/min water on VCL to 55,000 mL/min air and 2,800 mL/min water on VCH, and up to 300 LPM air and 9 LPM water on VT6. Flows are based on 10 psig inlet and atmospheric exhaust.

Q: Are the wetted materials suitable for corrosive or high purity media?
A: Yes. Fluids contact only PTFE and PCTFE. A rigid metal shell supports the PTFE body, a single PTFE o ring provides sealing, and compression can be adjusted by tightening the bushing for reliability and easy service.

Q: How do I choose between VCL, VCH, and VT6?
A: Choose VCL for low flow with Cv 0.011, VCH for higher flow with Cv 0.250, and VT6 for very high flow with Cv 0.765. Connections include 1/8 in FNPT, 1/4 in compression, 0.390 in glass nipples, and 3/8 in FNPT on VT6. Cole Parmer can help you match Cv and connections to your process.