Festo CPX-CMAX - Filter Regulator; Air Pressure Reservoir (Optional); Proportional Directional Control Valve VPWP and Drive

3 Mounting and pneumatic installation
34 Festo – P.BE-CPX-CMAX-SYS-EN – en 2017-09b – English
3.6.2 Filter regulator
 Use a filter regulator consisting of a compressed air filter and regulating valve (e.g. LFR-...-D-... with
5 ìm filter cartridge):
– without lubricator
– with a 5 μm filter
– with sufficiently large standard nominal flow rate corresponding to the air volume requirements
of the connected drive during positioning (reference value: 2 times the standard nominal flow
rate of the proportional directional control valve VPWP), e.g.:
Valve (fitting)
Filter regulator
VPWP-4-... (1/8) LFR-1/8-D-5M-MINI or MS4-LFR-1/4-D7-CRM-AS
VPWP-6-... (1/8) LFR-1/4-D-5M-MINI or MS4-LFR-1/4-D7-CRM-AS
VPWP-8-... (1/4) LFR-3/8-D-5M-MIDI or MS6-LFR-1/4-D7-CRM-AS
VPWP-10-... (3/8) LFR-3/4-D-5M-MAXI or MS6-LFR-3/8-D7-CRM-AS
Tab. 3.7 Selection of filter regulator
 Use a fine or micro filter if you cannot avoid a slight oil mist from the compressed air supply.
 Combine the filter regulator with a soft-start valve (e.g. HEL).
3.6.3 Air pressure reservoir (optional)
If the positioning behaviour does not conform to your requirements and fluctuations in pressure of over
1 bar are present at the pressure measuring point:
 Install an air pressure reservoir (e.g. CRVZS) between the filter regulator and the proportional direc
tional control valve.
This avoids pressure fluctuations during positioning operation. You can compensate for slight excesses
in the permitted pressure by using supply tubing with a larger diameter.
Volumes of the air pressure reservoir
The volume of the air pressure reservoir should be at least four times as large as the volume of the
drive used.
V
S
= 4 * V
Z
V
S
= Volume of the air pressure reservoir
V
Z
= Cylinder volume (linear drives: V
Z
= r
2
* ð* L
Z
)
L
Z
= Cylinder stroke length
r = 1/2 * cylinder diameter
ð L 3.14159
3.6.4 Proportional directional control valve VPWP and drive
Arrange the tubing between the valve (VPWP) and the drive symmetrically.
Recommendation for linear drives:
Always select tubing between cylinder and VPWP valve to be as short as possible. A tube
length of 60 % of the cylinder stroke length is optimal (max. tube length = cylinder stroke
length).