Flapper valve strip steel

Keywords: Valves, Compression, Steel

Specially, formulated for the flapper valves of automotive and stationary air conditioning compressors, the new Sandvik Hiflex strip steel is said to make possible smaller, more efficient compressor designs. It is of particular interest to producers of CO₂ compressors using high discharge pressures (Plate 1).

A flapper valve is one of the most important components in an air conditioning system. It is basically a spring made from pre-hardened steel whose function is to regulate the flow of refrigerant gas to and from the compressor through suction and exhaust valves. As such it is subjected to high cyclical loads and impact stresses.

 Plate 1Flapper valves made from Sandvik Steel’s new Sandvik Hiflex™ strip steel

The new Sandvik Hiflex stainless strip steel claims increased tensile strength and improved toughness. It is reported to have more than 10 per cent greater bending fatigue strength and 25 per cent improvement in impact fatigue resistance when compared with conventional and commonly used flapper valve stainless steels. It enables compressor designers to miniaturise compressors,use thinner valve flaps, increase reliability, or boost compressor efficiency with greater valve lift.

According to Sandvik the increase in bending fatigue strength has been made possible through the increased tensile strength of the material. The impact stress resistance has been improved both by the increased tensile strength and by a substantially higher internal damping capacity.

Sandvik Hiflex is reported to have a bending fatigue strength of ±120 ps and a maximum allowable impact velocity of 12.5 m/s (41 ft/s). It is said to enable designers to reduce the size of valves and compressors by using shorter valve tongues to achieve the same valve lift. In addition, the new steel is stated to allow increased valve lift in order to reduce pressure drop across the valve and boost compressor efficiency. Thinner valve flaps can reduce mechanical losses. The new steel can equally be used to improve the reliability of existing valves prone to fatigue failures.

Details available from: Sandvik Steel, Tel: +44 (0)121 504 5100; Fax: +44(0)121 504 5151; E-mail: sales.steeluk@sandvik.com;Web site: www.steel.sandvik.com