A family of other devices compliment the pressure regulator and valve offering, which include:
Check valves: A device which protects against reverse flow of a fluid.
Vacuum generators: A venturi device which creates vacuum via flow of N2. A variety of vacuum generators are available ranging from a simple venturi to modules which combine the venturi with a N2 inlet valve and check valve.
Flow switches: A safety device which senses excess flow in a gas line.