Bellow Seal Valve
Bellow Seal Valve
(OP)
What are Bellow seal Valves. Under what circumstances this requirement is called for. Is this related to the sealing requirement near the Gland packing area or it an alternative to that. Are there any International standards which specifies design method for this bellow seal valves?





RE: Bellow Seal Valve
Bellows seal valves are essentially valves which are less likely to have fugitive emissions problems by containing the valve stem mechanism in a bellows. Thus a valve stem packing leak will not leak to atmosphere. Due to the required flexibility of the bellows, the stems of these valves are LONG. They can be designed in for new construction, though that can be painful. Retrofitting into existing installations can be virtually impossible due to interferences.
Take a look at page 7 (in the .pdf, page 6 of the catalog)in http://www.velan.com/products/pdfs/vel-bs-2001-web.pdf for a good cutaway drawing of a bellows seal valve. A picture is worth a thousand words...
jt
RE: Bellow Seal Valve
RE: Bellow Seal Valve
Such an equivalence is defined, in quantitative terms, by the German Engineers’ guideline VDI 2440 (November 2000) about emission control in oil refineries.
Hope this helps, 'NGL
RE: Bellow Seal Valve
Thanks, 'NGL