Information from body of valve:

SHERWOOD
UL
3208
L57
3250A

Information from Relief Port:

S375 PSI – 366 CFM
DO NOT ADJUST

There is no Dip Tube

The following is speculation based on above information and may not be accurate.

Online research indicates this is PVE3250C-375
Liquid Withdrawal Valve 45Kg Cylinder (No ullage)
Shut-off and fill valve for 100 pound cylinders.

I believe these are valves for Liquid Petroleum Gas cylinders used on fork lifts or for vehicles modified to operate using LPG.