The needle valve block models

A valve with a needlelike part, a fine adjustment, or a small opening, especially a valve in which the opening is controlled by a needlelike or conical point that fits into a conical seat.  The needle valve block models a variable orifice created by a conical needle and a round sharp-edged orifice in thin material.
Needle valves within a block and bleed function help achieve positive isolation within maintenance operations of a live process plant. These work well in non-critical processes like with non-hazardous fluids or a low pressure system. The small port and needle-shaped, threaded plunger allows for precise flow regulation in low flow applications. Not only for maintenance, needle valves also work well in flow-metering operations, and are especially good at maintaining a calibrated and constant low flow rate.

Needle valves are usually used in flow-metering applications

Needle valves are usually used in flow-metering applications, especially when a constant, calibrated, low flow rate must be maintained for some time, such as the idle fuel flow in a carburetor.
Small, simple needle valves are often used as bleed valves in water-heating applications. Unlike a ball valve or valves with a rising stem, it is not easy to tell from examining the handle position whether the valve is open or closed.
Needle valves may also be used in vacuum systems, when a precise control of gas flow is required, at low pressure, such as when filling gas-filled vacuum tubes, gas lasers and similar devices.

the safety and reliability of a standard trunnion ball valve

An instrument needle valve uses a tapered pin to gradually open a space for 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.

The stainless steel ball valve and needle valves

The stainless steel ball valve and needle valves, for fractional tubes, are used with most of clean air engineering's instrumentation. The ball and needle valve are designed for high pressure applications in a corrosive environment. For custom sizes, please contact a sales representative today. We stock a variety of sizes of Ball and Needle Valve and usually ships same day.
Needle Valves with Stainless Steel shells and bushings are constructed of PTFE and external non-fluid contacting parts of anodized Aluminum for corrosive gas, liquid, and high purity regulation. Can also be used as bubble tight shut off valves.

FD-LOK have the most comprehensive range of instrumentation needle valves

FD-LOK  featuring the World’s most comprehensive range of instrumentation needle valves. The stainless steel needle valves range is designed and manufactured to the highest standards to meet the requirements of the severe applications anticipated for these valves. They have a split stem design, which ensures accurate seating, and a bubble tight seal. They are general-purpose valves for use on liquid or gas applications where the isolation of flow, equalisation and venting of pressure are the main criteria. The stainless steel needle valves is available ex stock with a variety of end connections from 1/4″ to 3/4″, giving any combination of ends from NPT, BSPP, BSPT, Single and Twin ferrule OD compression. They are available for application up to 10,000 psi and temperatures up to 400 degrees centigrade.

Needle valve to use

Needle valve easy maintenance, simple ball valve, seals are generally activities,Instrument manifolds removal of the replacement is more convenient. When fully open or fully closed, the sealing surface and the dielectric isolation ball and seat, through the media, will not cause erosion of the valve sealing surface. Wide range of applications, from small diameter to a few millimeters to a few meters from high vacuum to high pressure can be applied. Because there are wiping Needle valve opening and closing process, so the media can be used with suspended solid particles.Instrument needle valve Grease should Needle valve metal materials, rubber parts, plastic parts and the working media are compatible. Working medium for the gas, can be used for example, JP 221 grease. Coated on the surface of the seal mounting groove of a thin layer of grease, coated with a thin layer of grease on the rubber seals, valve stem sealing surface and the friction surface coated with a thin layer of grease.

Needle valve structure analysis

Needle valve is solid move after pressure does not occur. With a floating ball valve are firmly seat after by media pressure, move the seat occurs, the seal is pressed onto the ball, Needle valve in order to protect the seal. Weekdays with the ball, the lower shaft with bearings, manipulating small torque, useful in high-pressure valve with large diameter. Needle valve characteristic is horizontal, and the flow is upward mobility, so the valve is closed the water pressure on the valve play a significant role in the film is, the higher the pressure the better sealing performance. Needle valve when the valve is working as a plane rotation, need to overcome the friction coefficient between the valves,Instrument needle valve and the impact it's not as big hydraulic valve. But to overcome the friction in the water under the lamination pressure. Was friction between the laminations through practical experiment, several Corfu little force increases.