The valve core of needle valve is a very sharp cone, which is inserted into the valve seat like a needle, so it is named.
Needle valves can withstand greater pressure and have good sealing performance than other types of valves, so they are generally used for the sealing of gas or liquid media with small flow and high pressure.
Instrument needle valve is an important part of instrument measurement pipeline system. It mainly includes stop valve and ball valve. Its function is to open or cut off pipeline passage.
Ferrule type instrument valve has the advantages of convenient installation and disassembly, tight connection, conducive to fire prevention, explosion-proof, high pressure resistance and good sealing performance. It is an advanced connection valve in power station, oil refining, chemical plant and instrument measurement pipeline.
The needle valve has good sealing performance and long service life. Even if the sealing surface is damaged, it only needs to replace vulnerable parts to continue to use.
Needle valve installation
During installation, pay attention to make the flow direction of medium consistent with the arrow on the valve body.
Manual stop valve and ball valve can be installed at any position of the pipeline.
Needle valve has threaded connection, ferrule connection and welding. This type of valve shall be installed horizontally in the pipeline.
Anti corrosion method of needle valve
First of all, the anti-corrosion of the valve body is mainly the correct selection of materials. Although the information on corrosion protection is very rich, it is not easy to choose it properly, because the problem of corrosion is very complex. The difficulty in selecting valve body materials lies in not only considering corrosion, but also considering pressure and temperature resistance, economic rationality, ease of purchase and other factors.
The second is to take lining measures, such as lead lining, aluminum lining, engineering plastics lining, natural rubber lining and various synthetic rubber lining. If the media conditions permit, this is an economical method.
Thirdly, when the pressure and temperature are not high, using non-metal as the main material of the valve can often effectively prevent corrosion.
In addition, the external surface of the needle valve is also subject to atmospheric corrosion. Generally, steel materials are protected by painting.
Working principle of needle valve
Needle valve is a valve that can be accurately adjusted. It has a wide range of uses, such as the cutting distance for flame cutting. The knob for adjusting flame temperature is needle valve. Instrument needle valve is an important part of instrument measurement pipeline system, mainly including stop valve and ball valve, which is used to open or cut off pipeline passage.
The function of any valve is to cut off the fluid. According to the different valve cores, it can be divided into stop valve, gate valve, plug valve, ball valve, butterfly valve, needle valve, etc. the valve core of needle valve is a very sharp cone, which is inserted into the valve seat like a needle, so it is named.
Needle valve shape is the most suitable for use with pressure gauge. General needle valve shapes are made into threaded connection. Nominal pressure: pn2.5 pn4 pn6.4 PN16 pn32mpa nominal diameter: dn5 ~ DN25 applicable media: oil, water, gas and other non corrosive or corrosive media applicable temperature: – 20 ℃ ~ + 440 ℃ – 70 ℃ ~ – 240 ℃ ≤ 540 ℃ ≤ 570 ℃ and other manufacturing materials: 20#, 1Cr18Ni9Ti, 304, 316, 316L, 12Cr1MoV, etc