There is significant demand for the InterApp butterfly valves range from engineering consumables and components supplier BMG, with more than 100 units sold a month.

Valves from the range have recently been supplied for chemical applications at mining operations and processing plants in Namibia and South Africa, BMG Fluid Technology Low Pressure business unit manager Willie Lamprecht tells Engineering News.

BMG’s strategy to enhance its fluid technology services to meet the growing market demand in Africa encompasses the introduction of products comprising the latest developments in design technologies, materials and coatings.

In line with this strategy, the InterApp butterfly valves range, acquired from engineering and manufacturing company OMSA in 2013, is constantly upgraded and modernised, says Lamprecht.

“Unlike a ball valve, the discs of butterfly valves are always present in the passageway within the flow. This means a pressure drop is induced in the flow, regardless of the position of the valve. Ball valves should be used only for isolation, whereas butterfly valves can be safely used for isolation and flow control.”

The InterApp Bianca and Desponia series of butterfly valves, offering good flow characteristics and low maintenance requirements, are compact, extremely versatile and ensure dependable operation, even in the toughest environments, adds Lamprecht.

The InterApp Bianca centric butterfly valves, with durable polytetrafluoroethylene (PTFE) liners, are built for a long-service life, and are suitable for aggressive and corrosive fluids and for applications where absolute purity is essential.

These high-performance valves are available in sizes between DN 32 and DN 900, manufactured with a ductile iron, carbon steel or stainless steel body. They can be individually configured by BMG to ensure dependable operation and the best safety in specific applications.

For example, the US Food and Drug Administration- (FDA-) compliant Bianca valves (DN 50 to DN 200) with mirror-polished stainless steel discs and high-purity PTFE liners, ensure safety during the production of active pharmaceutical ingredients. Bianca valves with perfluoroalkoxy- (PFA-) coated discs and PTFE liners are recommended for use in highly corrosive, chemical applications.

Valves in this range with specially selected conductive disc and liner materials conform with the explosion protection directive ATEX 94/9EG, ensuring safe operation in explosive environments.

Notable features of the Bianca series include a high liner collar, a PFA disc over-moulding on the shaft, as well as a lifetime preloaded safety shaft sealing, ensuring reliable primary and long-lasting secondary shaft sealing, even for demanding operating cycles and at high temperatures.

The chambered liner prevents cold flow at the flange sealing surface for increased service life, while the PTFE liner, in combination with the PFA overmoulded disc, ensures low friction and, thus, longer life of the system.

Other features include an external shaft-sealing mechanism to protect the valve neck hole and a robust self-lubricating and maintenance-free bushing. A stainless steel valve label allows for full traceability.

BMG stocks a range of semifinished components to offer short delivery times, even on large sizes of the Bianca series.

Typical applications for Bianca butterfly valves are in mining and slurries for the extraction of acids and solvents, the processing of additives in the oil and gas sector and highly corrosive processes in the steel industry. This series is also suitable for use in water treatment where the smallest impurities need to be avoided.

Further, BMG’s multipurpose InterApp Desponia and Desponia Plus centric butterfly valves, with a tough body and robust elastomer liners, are designed for safe and reliable regulation of liquids and gases in diverse sectors.

Desponia valves, available in sizes from DN 25 to DN 1 600 and in pressures of up to 16 bar, are suitable for various industrial applications. This range can be supplied with a cast iron and ductile iron body.

The Desponia Plus range, available in sizes of between DN 25 and DN 600, with high-pressure applications up to 20 bar and is suitable for high-temperature or vacuum applications, as well as process automation. This range is available with a body made of ductile iron, cast iron or stainless steel.

The liners and discs of this series play a crucial role in elastomer-lined butterfly valves, as they are the only two parts that are in contact with the fluid. Flucast liners are suitable for abrasive applications and also meet FDA and European Union regulations.

An external shaft sealing mechanism protects the valve neck hole, while a long neck design allows pipe insulation. A retaining washer, which offers blow-out protection, and O-rings built in the shaft passage form part of the reliable shaft sealing system.

Sealing lips on the flange face offer perfect tightness and the optimised liner shape ensures a precise grip to the body. The square driven disc offers effective and durable torque transmission and polished disc edges reduce friction.

The Desponia range ensures safe operation in water treatment processes, as well as in power generation and demanding chemical processing applications. These valves can also withstand operation in the steel industry, where shut-off valves used to gas molten steel are exposed to harsh conditions.