The general gear pump pressure relay includes three parts: pressure sensing, force transmission and electrical microswitch. The pressure sensing elements include rubber film, 16L / W real spring tube and bellows, and the force transmission parts include plunger movement, lever transmission and return spring limit.

The pressure relays are membrane type (such as dp-63 type made in China), plunger type (such as Rexroth hied4 type), spring tube type (such as Rexroth hed2 type) and bellows type (such as DP type made in China), etc.