Stainless steel bellows sealed valves cut costs

Edited by the Engineeringtalk editorial team Sep 13, 2004

Two new PN40 flanged bellows sealed valves from Spirax Sarco offer low maintenance costs for hygienic applications that demand noncorrosive equipment.

Two new PN40 flanged bellows sealed valves from Spirax Sarco offer low maintenance costs for hygienic applications that demand noncorrosive equipment.

Such applications are typically in the food and beverage, pharmaceutical and chemical industries.

The BSA6T and BSA64T valves are among the first stainless steel bellows sealed PN40 valves on the market.

The fully stainless steel BSA6T valve is protected against internal corrosion from the process fluid as well as external attack from the atmosphere.

The lower cost BSA64T, which has a stainless steel body and carbon steel bonnet, is suitable for applications where only the process fluid is likely to cause corrosion.

Both are available in sizes DN15 to DN100.

Bellows sealed valves prevent fugitive emissions and offer lower maintenance costs than conventional gland packed valves.

In a gland packed valve, wear of the packing occurs each time the valve is operated, which can degrade the seal with the valve stem.

Extra load then needs to be applied by adjusting the gland to maintain a seal.

The packing continues to wear, making it less effective at preventing fugitive emissions and more difficult to operate the valve.

Eventually the packing must be replaced.

Bellows sealing overcomes these problems.

The bellows element absorbs movement to maintain perfect stem sealing.

Bellows sealing also withstands prolonged exposure to corrosive media that can cause gland packing to deteriorate.

All Spirax Sarco bellows sealed valves meet the most stringent emissions legislation worldwide, which is widely recognised as being the US Clean Air Act 1990.

This specifies that VOC (volatile organic compounds) emission levels should be less than 500ppm.

Every valve is pressure tested with helium during production to ensure zero emissions.

Spirax Sarco guarantees, for the life of the valve, every bellows unit against failure caused by manufacturing defects.