The "needle" in a needle valve is a thin valve stem that lowers or raises through a seat, thus regulating flow of gases or liquids. Sometimes the flow through a needle valve includes a 90-degree turn. The important feature of needle valves is fine threading, which facilitates precise, steady flow. Alternatively, some needle valves, like pneumatic needle valves, implement actuators for precise control.

Needle valves are ideal for use with gauges that may otherwise break due to flow surges that occur with other types of valves. They are also useful for applications that require slow shutoff, low flow or flow adjustments at high tolerances. Additionally, needle valves achieve a tight shutoff.

Industrial needle valves consist of two main components: the needle and the seat. The needle is usually made of brass or stainless steel, and the seat of an elastomer like PVC or PTFE. However, in order to comply with a wider range of applications, like those involving corrosive gases or fluids, needle valve manufacturers produce needle valves in multiple material combinations:

1. Metal needle with plastic seat needle valves

2. Metal needle with metal seat needle valves

3. Plastic needle with plastic seat needle valves

Action Steps
The best contacts and resources to help you get it done

Buy from a quality needle valve manufacturer or from needle valve distributors

Needle valve sources are not as plentiful as sources of more common valves, but there are still many to choose from. So if you don't find what you like at one source, move on to the next. Also, once you've found what you want, do a little price checking, especially if you are buying in volume.

I recommend: Grainger carries an extensive line of basic needle valves, mostly brass straight-through-flow types. Another option is Swagelok, which carries power needle valves as well as ones that rate up to 10,000 psig.

Find specialty needle valves and needle valve information

Needle valves service high tolerance and specialty applications more often than, for instance, ball valves do. Some websites offer information that will help you choose the suitable needle valve for your exact application.

I recommend: Ideal Valve Incorporated is a needle valve supplier with a nice page to help with flow calculations for both liquids and gases. They also offer high-precision specialty needle valves for sale. If you are looking for the right seat type for the type of gas or fluid you're working with, NOSHOK is a place to start.

Install, maintain or repair your industrial needle valves

When installing, operating and maintaining your needle valves, pay close attention to manufacturer's information. Product care and installation varies from one application to the next, depending on the material composition of the needle valve, the method of opening or closing the valve and the gas or liquid that will pass through it. Many applications may require periodic cleaning.

I recommend: Some manufactures have industrial needle valve use information right on their websites, and also provide repair services. There are repair-focused companies, like Instrument Service Contractors, Inc. and Team Industrial Services, which perform precision repairs and refurbishments.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Precision needle valves are a bad choice for viscous fluids because they will clog.