Pneumatic Control for Hydraulic Sequential Power Systems

Abstract

More than 80 per cent of all industrial hydraulic systems and about 40 per cent of industrial pneumatic power systems are electrically controlled. Why do we find this high percentage of ‘foreign’ control in fluid power, when fluid power itself is quite capable of controlling its own power circuits? The main reason for this phenomenon is the lack of education in the fluid power field itself. For many years electrical control was considered to be ‘the only solution’ for fluid power sequential and combinational control. Electricians and electronic technicians were taught the rules and methods of logic industrial control. This promptly resulted in the use of electrical and electronic switching hardware for fluid power control. Electrical logic is still a compulsory subject in most technical education programs for machine design engineers, draughtsmen and technicians, whereas fluid power logic and methodical fluid power control is only an elective subject or, indeed, not taught at all. It is the aim of this chapter to remove this stigma and to promote the reputation of fluid power as an ideal means of controlling sequential and combinational hydraulic power systems.