Patent ID: 7128090
Filing Date: 2006-10-31
Classification: F16K,F16L,Y10T

Abstract:
1. A water-hammer preventing unit for a check valve comprising: a valve body holder having a flow path; a hollow and short pipe having openings at two edges thereof with the opening at one edge thereof communicating to the flow path in the said valve holder; a valve body provided in the said valve body holder so that the flow path can be opened or closed; an energizing member for energizing the said valve body in the valve-closing direction; a retainer pipe having openings at two edges thereof provided in the said short pipe to form a circular space with the short pipe with an opening formed on the peripheral wall thereof; and an elastic tube provided on an external peripheral surface of the said retainer pipe and covering the opening, wherein a communication path is formed between the short pipe and the valve body holder, and the communication path communicates the circular space to the flow path in the upstream side of the valve body and, when a fluid flows in the reverse direction, a portion of the fluid is accommodated from the opening into the circular space by expanding the elastic tube toward the circular space, and also flows a portion of the fluid in the said circular space to the flow path in the upstream side from the valve body.