How to buy bellows seal valve
How to buy bellows seal valve?
When the medium is toxic, volatile, radioactive or extremely expensive, it is not allowed to be leaked by the reciprocating valve stem, the bellows is often used to seal the valve cover. This special bonnet structure can protect the valve stem and valve packing from contacting with the process fluid. At the same time, the standard or environmental protection stuffing box structure is adopted on the bellows sealing element, which can avoid the disastrous consequences in case of bellows rupture and failure. Therefore, pay attention to observe whether the valve stem packing leaks. If the packing leaks, the bellows valve may have problems.
There are usually two types of bellows for regulating valves, one is machined and the other is welded sheet bellows. The overall height of welded sheet bellows is relatively low, but its service life may be limited due to its manufacturing method and internal structural defects; Compared with the machined bellows, the overall height is higher, but the reliability is higher and the service life is longer.
Problems needing attention in application
The pressure rating of bellows seal decreases with the increase of temperature. The form of bellows seal should be carefully considered. After installation, special attention should be paid to correct use and maintenance to achieve the longest cycle action life.
Typical bellows products
Adopting the straight stroke valve body structure with bellows sealing the upper bonnet and considering the corresponding factors, it can become a bellows seal valve.
(1) Bellows sealed small diameter single seat regulating valve
The valve body adopts HV3000 series small diameter single seat regulating valve, which is a high-performance upper guide structure regulating valve. The CV value ranges from 0.01 to 1.4. Except for the slight increase of the overall height and weight, the data of other valve bodies are basically the same.
Pneumatic small diameter corrugated seal single seat valve
(2) Bellows sealed single seat regulating valve
The valve body adopts HV3000 series single seat regulating valve, which is an upper guide structure regulating valve, DN: 40 ~ 200. Except for the slight increase in overall height and weight, the data of other valve bodies are basically the same.
(3) Bellows sealed cage type double seat regulating valve
The valve body adopts HV3000 series cage type double seat regulating valve, which is a pressure balanced regulating valve with DN of 40 ~ 200. Except that the overall height and weight are slightly improved, the data of other valve bodies are basically the same.
For occasions where the requirements for wet chlorine gas (solving the problem of corrosion resistance) are not particularly high, the method of “rotary valve + multi-stage packing” can be adopted. For example, a fully functional ultra light regulating valve with multi-stage flexible graphite packing.
Source: Network Arrangement – China Bellows Seal Valve Manufacturer – Yaang Pipe Industry Co., Limited (www.ugsteelmill.com)
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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