From FestoWiki - english
When dealing with pneumatics, too, proportional technology has long been used with valves.
As the name already indicates, a proportional valve is a valve which can be used to change the output result proportionally to the value at the input.
For example: the higher the flow, the larger the flow rate.
We distinguish between two different proportional valves.
Proportional directional control valves
These valves are also designated as dynamic control valves.
The directly actuated proportional directional control valve MPYE-... has a position-controlled spool. This transforms an analogue input signal (voltage or current intensity) into a corresponding opening cross-section at the valve outputs. In combination with an external position controller and displacement encoder, a precise pneumatic positioning system can be created.
The 5/3-way proportional directional control valve VPWP, fully digitalised – with integrated pressure sensor with diagnostic functions.
Pre-assembled cables guarantee faultless and fast connection with the controllers CPX-CMPX and CPX-CMAX.
Clear installation and fast commissioning
Reduction of system downtimes thanks to the diagnostics options
With switching output for actuating a brake/clamping unit
Our pressure regulators all work proportionally - in spite of this, we only speak of some of them as proportional-pressure regulators, namely the solenoid actuated regulators.
Our range of products includes various proportional-pressure regulators with different modes of operation.
Proportional-pressure regulators work with a closed control circuit.
The input variable is continuously compared with the output pressure. If a system deviation occurs, the proportional-pressure regulator adjusts accordingly.
If, due to an EMERGENCY OFF, the electrical supply of the proportional-pressure regulator is interrupted, the valve displays different characteristics depending on the type.
|Valve type|| EMERGENCY OFF characteristics |
|VPPM-...|| on interruption of the electrical power supply, the output pressure is maintained but unregulated |
|VPPE-...|| on interruption of the electrical power supply, the output pressure is maintained but unregulated |
|MPPE-...|| on interruption of the electrical power supply, the output pressure is maintained but unregulated |
|MPPES-...||on interruption of the electrical power supply, the output pressure is not maintained|
Of course, a proportional-pressure regulator which has been designed for a maximum pressure of 10 bar can also be adjusted to a pressure range of 0.8 bar, but more accurate results are achieved using a proportional-pressure regulator designed for a maximum pressure of 1 bar.
Also important is the operating pressure - the pressure applied to the primary side of the proportional-pressure regulator should be at least 1 bar higher than the maximum value which is set with the proportional-pressure regulator.