Tuesday, March 26, 2013

Swagelok Needle Valve Basics

Customers wanting the best in Needle Valves need look no further than Swagelok to meet all their needs. Swagelok Needle Valves are used in flow metering applications, where a constant, calibrated flow must be maintained. A Needle Valve has a long tapered point at the end of the valve stem that is lowered through the seat to restrict or block flow, as required, and a needle-shaped plunger on the end of the screw which exactly fits the point. Fluid flowing through the valve turns at 90 degrees, and passes through the orifice that is the seat for a rod with a cone shaped tip. The finely threaded stem, and large seat area allow for the precise calibration of resistance to flow. As the plunger is retracted, flow between is possible - until the plunger is completely retracted, fluid flow is impeded.

Needle Valves must be easy to shut off, and pressure sensitive to maintain the correct level of flow. The Valves must allow for precise adjustments of flow, and be adjustable to conform to the requirements of a particular system - Needle Valves require many turns of the valve stem to open or close, which means a range of flow, can be allowed for. They are used control flow into delicate gauges, where sudden surges of pressurized fluid can cause damaged, and in situations where flow must be gradually, and precisely brought to a halt. They are also used where a small rate of flow is required. They are not for use in simple shut off applications. The valves should be easy to shut off completely with no more than 'finger tight' pressure. Swagelok Valves guarantee a long service life, and compact design.

Needle Valves are designed in many different materials. The valve is generally metal - here stainless steel, or a steel alloy, brass, or bronze are most often used, The seat is usually made from an elastomeric material such as PVC, CPVC, PTFE or a suitable type of the wide range of plastics and thermoplastics on the market. Valves are available in different materials - here customer choice will be determine by the specific application the valve is to be used for, along with the conditions it will be subject to. You have to take into account whether the fluid is particularly high or low in temperature, likelihood of corrosion, and how much wear the valve will be subject to you. Swagelok will be able to consult with you, and advise you what type of valve is best for the application you require it for. Swagelok Tube Fittings are available in additional Valve Body Materials on request - these include carbon steel and 25Cr super duplex stainless steel.

Needle Valves are used whenever control or metering of steam, air, gas, oil, water or other non-viscous liquids is required. This means they are used in almost every industry over a massive range of applications. Swagelok Valves are all factory tested with nitrogen at 1000 psig (69) bar to ensure that seats have a maximum allowable leak rate of 0.1 stdcm3/minute, and shell testing is performed to a requirement of no detectable leakage with a liquid leak detector.

Every Swagelok Valve is cleaned and packaged in accordance with Swagelok Standard Cleaning and Packaging to ensure the customer's peace of mine. Swagelok Needle Valves can be ordered with multiple options, including, depending on the type of Valve required, High-Temperature Stem Packing and Bonnet Seal, Anti-tamper Handles and Keys, and Round Lockable Handles available in nylon, and stainless steel for marine service. Swagelok Valves offer you peace of mind with all your Needle Valve requirements, and a large variety to choose from, including General Utility Service Valves, Sever-Service Union-Bonnet Needles Valves, Screwed-Bonnet Needles Valves and many others. Consult the Swagelok sales team for advice on all your Swagelok Valves requirements.

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