Industrial Vacuum Inlet Valves up to 6″Ø MNPT = Male National Pipe Thread 1 1/2″ and 2″ inlet valves are aluminum with a spring loaded self closing cover. 2 1/2″ to 6″ vacuum inlet valves features a Sch. 40 body, machined inside, with 11 Ga. spring loaded steel plate, painted.  Inlet Valves have a large palm plate to assist opening under high vacuum.
Part No.	Hose Size	MNPT
VC-150	1 1/2	2
VC-180	1.8 (Spencer)	2
VC-200	2	2
VC-250	2 1/2	2 1/2
VC-300	3	3
VC-400	4	4

Self closing vacuum inlet valves are typically installed at the end of a piping run. Self closing inlet valves permit an operator to connect his vacuum hose to the vacuum system by opening the self closing flap on the inlet valve. The operator can then insert a vacuum hose equipped with a tapered inlet adapter into the inlet valve. The inlet valve is designed so that the tapered adapter friction fits perfectly into the valve. All the vacuum air passes through the vacuum inlet valve at this point, allowing the operator of the vacuum hose to clean up spills or whatever cleanup duty he is performing. The vacuum inlet valve can be disconnected by simply removing the tapered adapter from the inlet valve. The self closing flap on the valve has a gasket on it that will seal the vacuum off once the flap automatically closes. The valves are also available with an electric switch. Once the valve is opened, a switch will automatically close. This can send an electrically signal to an electrical starter, which in turn, can turn on the vacuum. When the hose is disconnected the contact is no longer closed and the vacuum can shut off automatically. If you add an E at the end of the part number, it denotes that the self closing vacuum inlet valves is an electrical type valve.