Anver Corp. (Hudson, Mass.) has introduced the Anver CheckVac line of leak-proof vacuum check valves designed to replace compressed-air pressure valves and improve vacuum pump efficiency. The valve design features a one-piece aluminum body and a plastic element with a softer spring than the check valves used in compressed-air systems. This one-way valve reportedly minimizes the loss of flow by not wasting the pump’s power opening the stiffer spring found in a compressed-air check valve. The valves are available in 0.25-inch to 2-inch (6.35-mm to 50.8-mm) NPT sizes and have stainless steel internal springs, plastic valve elements and O-ring seals.