a regulator in which the pressure of a liquid fed from a constant supply acts on a regulating mechanism. Hydraulic regulators are usually designed to function according to the integral, proportional, or integral-proportional laws of regulation.
Membranes, bellows, and other devices that transform the value being measured into a proportional force (less frequently, into a proportional movement) serve as the receiving (sensing) elements of hydraulic regulators. Hydraulic actuating mechanisms based on double-action hydraulic cylinders are most often used in hydraulic regulators, but relatively simple hydraulic regulators may utilize single-action membrane actuating mechanisms. A hydraulic regulator’s advantages include dependability, simplicity of design and maintenance, and small size and weight. Its main shortcoming is the need for constant monitoring of leaks of the operating liquid.