Needle valve manual: Instrument needle valve shut-off valve and the main valve, its purpose is to be turned on or off with piping pathway, is the instrument measuring an important part of the piping system. Card sets with easy installation and removal instrument valves, connections are tight, there is conducive to fire, explosion, and high voltage capability, good sealing performance, etc., are power plants, oil refineries, chemical equipment and instrument measuring the line of an advanced connection valve. Needle valve sealing good, long life, even if the sealing surface is damaged, only need to replace wearing parts, you can continue to use. Installation should pay attention to the flow of the medium with the same direction of the arrow on the valve body. Manual shut-off valve ball valve can be installed in any position in the pipeline. Needle valve with threaded connections, welded sleeve connection. Needle valve is usually made ??up of body, valve cover, valve （gate）, seat, stem, heat sink, fillers and the drive unit （hand wheel, gear box or pneumatic, electrical devices, etc.） components. Needle valve in the valve body and bonnet material for the shell material （also known as the main material）, gate （valve）, ball, seat, stem, sealing seat is often referred to as the inner parts, in addition to tight firmware seals.