Reed valves, flapper valves, leaf valves and valve retainers are typically used in refrigeration compressors for the civil, industrial and automotive sectors. They are mechanically critical components that define the characteristics and the quality of a compressor, which are very demanding in terms of dimensional tolerances, roughness, impact and fatigue resistance. Their main characteristic is the ability to withstand stress created by repeated bending without breaking.
The dimensional and mechanical characteristics requested by the Customers are obtained thanks to the use of particular materials and of specially-developed production technologies. As for materials, the flapper valves and the reed valves are obtained from very thin ribbons of tempered steel, developped specifically for this application and supplied only by a limited number of qualified manufacturers worldwide; carbon steels or stainless steels are used, depending on Customers' requirements.
For this reason, we do not just blank metal, but we control all the factors that affect the life expectancy of the reed valve, that is several billions of cycles. These factors include geometry (for correct assembly and coupling during operation), flaws on the surface of the materials (scratches, roughness, impurities), applied and residual stress, temperature changes, bending, twisting and impacts. Last but not least, chemical aggression, including corrosion.
The need to improve the efficiency of the compressors requires minimizing the width of gaps between the moving and fixed parts of the reed valves: only refined blanking and finishing techniques allow containing the distances within a few tenths of a millimeters.