The closed primary shutoffs are designed to be welded to the machine, where the vacuum line starts. The closed primary shutoffs are equipped with an "overflow" system with a stainless steel floating ball. This system prevents the suctioned material (liquids or similar) from entering the vacuum line when the maximum level inside the tank is reached. The closed primary shutoffs are equipped with a series of side couplings that enable the connection of various types of accessories, such as vacuum breaker and safety valves, pressure gauges and vent systems and cyclone drains..