Purchasing skills of the hottest bellows sealing v

Purchasing skills of bellows sealing valve

when the medium is toxic, volatile, radioactive or extremely expensive, it is not allowed to be leaked by the reciprocating valve rod, the bellows sealing valve cover is often used. This special bonnet structure can protect the valve stem and valve packing from contacting with the process fluid. At the same time, the use of standard or environmental protection stuffing box structure on the bellows sealing element can avoid the disastrous consequences in case of bellows rupture and failure. Therefore, pay attention to observe whether the valve stem packing is leaking at ordinary times. If the packing leaks, the bellows valve may have problems

first, the structural form of bellows

there are usually two kinds of bellows used 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; The bellows formed by machining has higher overall height, higher reliability and longer service life

II. There should be two kinds of equipment. No matter which model should be paid attention to in use.

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 the excellent performance of the fluororubber material to the automotive transmission parts, correct use and maintenance, so as to achieve the longest cycle action life

III. typical bellows products

adopt a straight stroke valve body structure with a bellows seal on the bonnet and consider the corresponding factors to become a bellows seal valve

pneumatic small-diameter corrugated seal single seat valve

(1) bellows seal small-diameter single seat adjustment each express has a waybill valve

the valve body component adopts hv3000 series small-diameter single seat adjustment valve when the rate is ≥ 0.05%fs/s. It is a high-performance upper guide structure regulating valve, and the CV value range is 0.01 ~ 1.4. Except for the slight increase in the overall height and weight, the data of other valve bodies are basically the same

(2) bellows sealed single seat regulating valve

the valve body part adopts hv3000 series single seat regulating valve, which is an upper guiding 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 part adopts hv3000 series cage type double seat regulating valve, which is a pressure balanced 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

IV. economic alternatives

for occasions where the requirements for wet chlorine gas (to solve the problem of corrosion resistance) are not particularly high, the method of "rotating valve + multi-stage packing" can be adopted. For example, the full-function ultra light regulating valve with multi-stage flexible graphite packing