Type needle valve is a valve can be precisely adjusted, has a wide use, such as flame cutting with the cutting distance, the flame temperature adjustment knob is the needle valve. Instrument type needle valve is pipe fittings manufacturer an important part of the meter in the piping system, mainly cut-off valve and ball valve, its function is used as open or cut off the pipeline path. Needle valve valve core is a very sharp cone, like the needle inserted into the seat, hence the name. Needle valve compared with other types of valves, can tolerate more pressure, sealed performance is good, so commonly used in small flow, high pressure gas or liquid medium sealing, needle valve and pressure gauge is used the most suitable, general type needle valve type screw thread connection. The anti-corrosion methods
1, the body of the main material is stainless steel, carbon steel. Choose the difficulty of the body material, also is not only considered the corrosion problem, at the same time must consider pressure and heat-resistant ability, economically reasonable, buy whether factors such as easily.
2, the lining measures, such as lining, lining aluminum, lead lining engineering plastics, lining natural rubber and various synthetic rubber, etc. Such as medium conditions permit, it is a way to save.
3, in the case of pressure, temperature is tube fitting manufacturer not high, do the valve body with nonmetal material, often can effectively control the corrosion.
4, in addition, the needle valve body surface by atmospheric corrosion, general steel material is to brush paint protection.
Four, installation considerations
1, installation position and height, import and export direction must comply with the design requirements, pay attention to the medium flow direction should be consistent with the body the direction of the arrow, the connection should be firmly connected.
2, a visual inspection must be conducted before installation of valve, the valve nameplate should be consistent with existing national standards "universal signal valve" GB 12220.
3, for the working pressure is greater than 1.0 MPa and 14 tube fitting the valve with the function of cutting off on ZhuGanGuan, strength and strict performance test should be done before the installation, qualified rear must use. Strength test, the test pressure is 1.5 times the nominal pressure, duration of not less than 5 min, shell and packing shall be no leakage of valve shall be qualified. Leak test, the test pressure is 1.1 times the nominal pressure; The duration of the test meet the requirements of GB 50243.
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