Abstract: A valve-venting method increases the durability of flow restrictors within gas venting valves used on large diameter water and sewer pipelines such that transient high pressure conditions that can cause rapid adiabatic heating of the discharging gases are prevented from causing flow erosion and debris wear induced by the high velocities and thermal softening of the valve components. The method utilizes wear resistant orifice inserts that are more conductive than the valve component to better distribute the heat, and dynamic surge control geometry to slow the heat flow and provide progressive water-hammering control during high pressure events.

Abstract: Captive fasteners are provided that may be used with guards that cover particular areas of a machine. The fasteners are attached to the guards so that they remain with the guard when the guard is removed from the machine. In order to make it easier to reinstall the guard onto a machine when the guard is misaligned, the fasteners can move along a slotted opening in the guard.