Pneumatic Control Options for Hydraulic Systems
Air-Controlled Pressure Controls Explained
When to Use
|Many hydraulic equipment applications are in fire-prone, hazardous areas involving combustible or explosive materials, and require that any electrical device used meets "Intrinsically Safe" or "Explosion Proof" standards. Examples of these hazardous areas include:
- Electro-hydraulic devices that must operate in environments with very strong electromagnetic fields can suffer from stray induced currents. Strong electromagnetic fields are often present in manufacturing environments with a concentration of large projection and spot welding operations. These processes can create very strong magnetic fields, and can often induce large currents or "noise" into low level electrical control wires. This "noise" can send false signals to sensitive electro-hydraulic devices such as proportional pressure controls. Using air-controlled proportional hydraulic pressure controls with pneumatic control lines in place of electrical control wires completely eliminates this interference problem.
- Devices requiring variable hydraulic pressure and complete electrical isolation from another part of a machine, for safety reasons, may find proportional pneumatic control a practical solution. The pneumatic control lines can be rubber or elastomeric tubes and are thus an electrical insulator. With voltage potentials below where ionization of air occurs, there is no direct "electrical" connection present.
- Pneumatic proportional controllers and air-controlled hydraulic pressure controls can provide a lower cost solution in facilities where the pneumatic supply is readily available. Air-controlled hydraulic pressure controls can be used without the need to install proportional hydraulic amplifiers, associated electrical wiring, and power supplies necessary for electro-hydraulic systems. The only caution is that pneumatically controlled hydraulic pressure control systems typically have a much slower dynamic response time than their electro-hydraulic counterparts.