Chapter | one - Fundamental Principles

Abstract

Most industrial processes require objects or substances to be moved from one location to another, or a force to be applied to hold, shape or compress a product. Such activities are performed by prime movers, the workhorses of manufacturing industries. The main advantages and disadvantages of pneumatic or hydraulic systems both arise out of the different characteristics of low-density compressible gases and (relatively) high-density incompressible liquids. This chapter compares various advantages and disadvantages of electrical pneumatic and hydraulic systems. Hydraulic systems require a pressure regulator to spill excess fluid back to the tank, but pressure control in a hydraulic system is much simpler. Pneumatic and hydraulic systems generally rely on pressure in a fluid. Behavior of a fluid can generally be deduced from measurements of flow or pressure. Where more accurate pressure measurement is required, transducers based on the force balance principle are generally used.