Proportional valves
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.
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Proportional directional control valves
These valves are also designated as dynamic control valves.
Symbol: MPYE-... Symbol: VPWP-...
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.
Proportional directional control valve type MPYE-...
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.
Advantages:
Clear installation and fast commissioning
Reduction of system downtimes thanks to the diagnostics options
With switching output for actuating a brake/clamping unit
Proportional directional control valve VPWP-...
Proportional-pressure regulators
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.
Symbol: VPPM-... Symbol:MPPE-.../VPPE-... Symbol: MPPES-...
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.
Proportional-pressure regulator VPPM-...
EMERGENCY OFF
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 |
Pressure range
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.