Cepex PVC-U Manuel D'installation Et D'entretien page 9

ENGLISH
6. OPERATION OF THE ACTUATOR
6.1 SPRING RETURN NORMALLY CLOSED VALVE (Fig. 9)
The valve is closed without an air supply. When the actuator is supplied with
pressurized air, the valve opens. If the supply of the pressurized air is closed and
the air can escape, the valve will be closed because of the actuator's internal
springs.
A 3/2 solenoid valve or 5/2 solenoid valve is required to carry out the action. In
the case a normally closed monostable solenoid valve is installed, the electrical
signal should be maintained during the time that the valve needs to be kept open.
In the case of a spring return actuator, Cepex will normally serve the closed valve
as standard.
6.2 SPRING RETURN NORMALLY OPEN VALVE (Fig. 10)
The valve is opened without an air supply. When the actuator is supplied with
pressurized air, the valve closes. If the supply of the pressurized air is closed and the
air can escape, the valve will be opened because of the actuator's internal springs.
A 3/2 solenoid valve or 5/2 solenoid valve is required to carry out the action. In the
case a normally closed monostable solenoid valve is installed, the electrical signal
should be maintained during the time that the valve needs to be kept closed.
6.3 DOUBLE ACTING VALVE (Fig.11)
The valve has no defined fail safe position. The valve is opened and closed by
applying air pressure to the corresponding control connections.
A 5/2 solenoid valve is required to carry out the action. In the case a normally
closed monostable solenoid valve is installed, the electrical signal should be
maintained during the time that the valve needs to be kept open (according to
the drawing).
6.4 LIMIT SWITCH BOX
To electrically confirm the position of the valve, a limit switch box can be
mounted to the actuator according to NAMUR specification.
IP67 Protection. Temperature range: -20ºC to 80ºC.
Limit switch boxes are available made from plastic and aluminium.
Electromechanical SPDT switches are used as standard.
See the specific manual and the electrical diagram inside the box.
6.5 SOLENOID VALVE
Different types of solenoid valve can be installed defined by:
- 3/2 (3 ways, 2 positions) and 5/2 (5 ways, 2 positions).
- Power supply: 230 V AC, 110 V AC, 24 V AC, 24 V DC, 12 V DC.
- Monostable / bistable.
See the specific manual for more options.
Optionally, the solenoid valve can be sold included with the actuator; it can then be assembled in the factory attached to the
actuator (NAMUR VDE/VDI 3845 standard).
6.6 RELIEF REGULATORS
Cepex strongly recommend relief regulators be installed so as to control the actuator's operating speed and prevent water hammer.
The silencer can be included within the relief regulator.
EXTREME PNEUMATIC BALL VALVE
Fig. 9
CLOSED VALVE
Fig. 10
Fig. 11
CLOSED VALVE
OPEN VALVE
OPEN VALVE
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