Pneumatic solenoid valves can be categorized into two basic types, Direct Acting and Pilot Operated, each with characteristics and advantages, depending on your requirements.
Direct Acting Pneumatic
Solenoid Valve advantages:
Capable of operation under a full pressure range, including low pressure and vacuum.
Simple, reliable construction with few parts. Low cost.
More tolerant in poor or unstable media conditions.
Versatile, and valves can be tailored to specific applications.
Pilot Operated Solenoid Valves use
a Direct Acting Solenoid Valve as a pilot operator. The pilot operator
functions to shift a larger directional control valve of piston poppet or
spool design. Pilot Operated Pneumatic Solenoid Valves advantages:
Achieves high flow capacity relative to physical size.
Consumes less current (amperage) relative to flow capacity.
Many configurations to select from, particularly in four way functions.
Designed primarily for efficient control of air cylinders & air actuators.