By action and use
A device used to control the direction, pressure, and flow of a fluid in a fluid system is a means for flowing or stopping the medium (liquid, gas, powder) in the piping and equipment and capable of controlling its flow.
The valve is the control part of the pipeline fluid conveying system, which is used to change the channel section and the flow direction of the medium, and has the functions of diversion, cut-off, throttling, stop, shunt or overflow relief. Valves for fluid control, from the simplest cut-off valve to the extremely complex automatic control system used in a variety of valves, its variety and specifications, the nominal diameter of the valve from a very small instrument valve to a diameter of 10m Industrial piping valves. Can be used to control water, steam, oil, gas, mud, all kinds of corrosive media, liquid metal and radioactive fluid and other types of fluid flow, the valve working pressure from 0.0013MPa to 1000MPa of ultra high pressure, the working temperature can C-270 ℃ ultra-low temperature to 1430 ℃ high temperature.
Valve control can be used in a variety of transmission methods, such as manual, electric, hydraulic, pneumatic, turbine, electromagnetic, electromagnetic hydraulic, electro-hydraulic, gas-liquid, spur gear, bevel gear drive; Or other forms of sensor signals, according to the intended requirements of action, or do not rely on the sensor signal for a simple open or closed, the valve by the drive or automatic mechanism to make the opening and closing parts for lifting, sliding, swing or turn Movement, thereby changing the size of its flow area to achieve its control function.
The parts of the valve must be processed before assembly:
1, according to processing requirements, some parts need to do polishing, the surface can not have processing burr;
2, all parts of the degreasing treatment;
3, degreasing after pickling passivation, cleaning agent does not contain phosphorus;
4, pickling with pure water after washing, can not have the residue, carbon steel parts to save this step;
5, one by one parts with non-woven fabrics to dry, can not be wired hair and other parts of the remaining parts, or clean with a dry nitrogen;
6, with non-woven or precision filter paper analysis of pure alcohol on each component to wipe, until no dirty color.
Clean parts must be sealed for installation.
The installation process requirements are as follows:
1, the installation workshop must ensure that clean, or set up a temporary clean area, such as the use of new color cloth or plastic film, etc., to prevent dust in the installation process to enter.
2, assembly workers must be dressed in clean cotton overalls, wearing a cotton cap, hair can not leak, wear clean shoes, wearing plastic gloves, skimmed.
3, assembly tools must be assembled before the degreasing cleaning, to ensure clean.
1, the assembly of the valve with nitrogen blowing at least 1 minute.
2, airtight test must be pure nitrogen.
3, airtight test qualified after the package, sealed with a clean polyethylene cap, polyethylene cap before the application of organic solvent soak, wipe clean.
4, then sealed with a vacuum bag.
5, the final packing.
6, the transport process to take measures to ensure that the package is not damaged.
Acceptance follow HG 20202-2000 "degreasing construction and acceptance of norms", before assembly, each parts are cleaned with a clean precision filter paper, select the parts dead, filter paper unchanged color is qualified.