Comparison of application efficiency of multi-disk grinding heads when forming the sealing surface of the pipeline fitting gate valve

Abstract

The purpose of the paper is the experimental comparison of the application efficiency of multi-disk grinding heads forming and restoring the sealing surfaces of pipeline valves on example of the part simulating the “saddle” of DN 65 low pressure valve. Experiments on contact surface sealing in the gate valve are conducted with the use of grinding heads with three and five working disks. Increase in the number of working disks in multi-disk grinding heads from three to five has improved the quality of the processed surface by reducing the deviation from the plane for EFCO abrasive tool from 6.57 to 5.14 μm; for L251SM40 grinding cloth - from 8.14 to 7.14 μm, as well has decreased the average value of the roughness parameter Ra from (0.226 - 0.277 μm) to (0.087 - 0.148 μm) depending on the type of the abrasive cloth. An increase in the gradient of the friction coefficient at multidisc treatment improves the processing quality of sealing surfaces. Since the deviation from the nominal plane is decisive after processing, grinding of sealing surfaces is recommended to perform with the use of a 5-disk grinding head with EFCO abrasive cloth. This is confirmed by the formation of a closed zone of contact spots on the sealing surfaces of witness parts providing the tightness of the gate valve assembly of pipeline fittings. For sealing surface lapping, it is recommended to use a 5-disc grinding head with the use of EFCO abrasive cloth, which ensures the tightness of the gate valve assembly of the pipeline fittings.