Primary valves are designed to be welded on top of the vacuum truck tank, at the point where the vacuum/pressure line begins. They feature an integrated overflow system with a stainless steel float ball. When the tank reaches the maximum fill level, the valve prevents liquid from entering the vacuum line and reaching the pump.

Additionally, they are equipped with the following accessories: removable cover, threaded coupling for pressure relief/vacuum adjustment valve, pressure gauges, ventilation system, and cyclone valve discharge.