An instrument needle 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 valves 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.

A needle valve is a type of valve

A needle valve is a type of valve having a small port and a threaded, needle-shaped plunger. It allows precise regulation of flow, although it is generally only capable of relatively low flow rates.
The virtue of the High pressure needle valve is from the vernier effect of the ratio between the needle's length and its diameter, or the difference in diameter between needle and seat. A long travel axially (the control input) makes for a very small and precise change radially (affecting the resultant flow).
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.

Stainless steel needle valve Installation notes

Stainless steel needle valve Installation notes:
1, the installation position, altitude, direction and export must meet the design requirements, pay attention to the direction of media flow valve should be consistent with the direction of the arrow mark, the connection should be firmly tight.
2, must be visually checked before the Check valve is installed, the valve plate should be consistent with existing national standards.
3, for the working pressure greater than 32.0 MPa and the role played off valves on the main pipe, the installation should be carried out before the strength and rigorous performance tests, passing behind the prospective use.
4, the strength test, the test pressure for the nominal pressure of 1.5 times the duration of not less than 5min, the valve housing, packing should be no leakage in compliance.
5, when the tightness test, the test pressure of 1.1 times the nominal pressure; test duration in line with national standards.

Stainless steel needle valve selection principles

Stainless steel needle valve selection principles:
1, the pipeline system and cryogenic medium, should use low temperature plus bonnet SS needle valve.
2, the pipeline system FCCU refining apparatus, the choice of needle valve lift rod.
3, apparatus and piping systems of chemical systems and other corrosive acid medium, should use austenitic stainless steel, Teflon seat ring of stainless steel needle valve.
4, metallurgy systems, piping systems or devices on power systems, petrochemical plants, urban heating systems in high-temperature media, the choice of metal seal needle valve.
5, transporting oil products pipelines and storage facilities, the choice of the needle valve welded connection.
6, city gas and natural gas pipelines, the choice of the needle valve flange connection and female connection.
7, oxygen pipeline system, should be strictly degreased.

Selection principles stainless steel needle valve

Selection principles Stainless steel needle valve
1, the piping systems and devices require cryogenic medium, the best selection of plus bonnet cryogenic needle valve.
2, the pipeline system FCCU refining device, you can use the lift needle valve.
3, apparatus and piping systems of chemical systems and other corrosive acid medium, the best selection of austenitic stainless steel valve seat ring of stainless steel needle valve.
4, during the time flow regulation, to use traditional worm, pneumatic or electric with a V-shaped opening regulating needle valve.
5, city gas pipeline and natural gas, use thread connecting flange connections and needle valve.

Needle valve principle and characteristics

Material needle valve is generally used by the steel constructed, but there are seals made using a copper alloy valve head. and so. Before using the needle valve. It should open the inspection valve head and seat material. U-turn in order to prevent the use of the process or wear phenomena occur. In the fermentation process, the increased use of Stainless steel needle valve, to ensure strict degree play a role.
Features needle valve is:
(1) withstand high temperatures, high pressure and difficult to corrosion.
(2) Easy to trace the flow rate and flow control plus, dropping feeding.
(3) easy to operate, easy to replace, easy maintenance.

Disadvantage exists needle valve

Disadvantage exists needle valve
(1) easy to damage, especially easy to turn the valve head.
(2) because of the small structure, small channels, it is easy to be blocked.
With cut-off valve should pay attention to the mounting direction of the needle valve installation. And medium flow must coincide with the stainless steel needle valves is installed to maintain the packing at the needle valve closed when not affected by media pressure and leakage. In connection with the fermentation tank installation. We must pay attention to the fermentation tank being installed, to prevent the broth from the packing seal leakage and contamination.
Industrial production in the fermentation process, the needle valve is widely used in fuel control valve, red depending on the mirror steam valve, the steam control valve manifold material, the air blowing port on each valve, as well as sampling tubes on each control valve. These places need both easy maintenance and replacement, at the same time they need to withstand high temperatures and pressure. Controlling the flow rate, the valve flow. Needle valve just adapted to these requirements.

Stainless steel needle valve is an important part of ball valve

Stainless steel needle valves instrument measuring pipeline system is an important part of the main shut-off valve and ball valve, its function is to make open or cut off the pipeline pathway used.
Card sets of Instrument valves have easy installation and removal, connections are tight, there is conducive to fire, explosion and high voltage capability, good sealing performance, etc., are power plants, oil refineries, chemical plant and instrument measuring line in an advanced connection valve. This type valve in the pipe should generally be installed horizontally.
Stainless steel needle valve sealing good, long life, even if the sealing surface is damaged, only need to replace wearing parts, you can continue to use.
Base FD-LOK Stainless steel needle valves structure on self-designed, is currently the most common next-generation valve.
First, the body of anti-corrosion, mainly the correct selection of materials. Although the anti-corrosion materials is very rich, but whether the election was appropriate or not an easy thing, because corrosion problems are complex. Select body material difficulties, it lies not only consider the corrosion problem, but you must consider the pressure temperature capabilities, whether economically justified, is it easy to buy and other factors.