Metal-seated ball valves with zero leakage from A+

The ball valve is of vital importance to plant engineers as an efficient shut-off valve. The metal-seated ball sealing is the most important aspect and needs a close focus. The manufacturing of metal-seated ball valves is a very challenging and complex task particularly because the technical tightness (zero leakage) should be proved and achieved for a wide temperature range (ambient temperature up to 650°C).
 
The modern process technology demands corrosion resistant alloy material for sealing and disc. However, the ball and seat ring must not slide on top of each other constantly. A special hard coating for the ball and seat ring must be used to protect these parts against ‘seizing’. Approved methods are boride coating (a diffusion process) and high-speed coating (HVOF) with tungsten carbide and chrome carbide. These coatings are available in different thicknesses and hardness grades.

 
The lapping process at A+R Armaturen has been updated constantly in the recent years. A + R employs state-of-the-art CNC-lapping machines to produce exact lapping work of balls and seat rings. Currently A+R can produce more than 60 balls in one clamping completely automated and highly effective. If the ball and seat ring are precisely harmonised against each other, A+R metal-seated ball valves will withstand more than one hundred thousand switching operations without any damage and process interference.
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