Camozzi Pneumatics Manual

REST

FILLING

EXHAUST

Fig. 44

Thediagram illustrates the connectionof adoubleacting cylinderwithan intermediate stop.Bypressingoneof the

two 3/2-wayNC solenoid valves, C/A is supplied to the active chamber of the cylinder, simultaneously controlling

a blocking valve, which opens and allows the exhaust of C/A in the opposite chamber of the cylinder, the latter is

inmovement. In the rest position, the cylinder chambers are not suppliedwith C/A and cannot discharge because

the blocking valves are closed: the cylinder is blocked.

Bidirectional blocking valves

Aesthetically, unidirectional andbidirectional blocking valves haveno external differences, their operation is different

however. This version is usedwhen there is the need to close passages in all directions.

Figure 45

Pos. A

valve in rest position, no pilot signal.

The outlet 2 of the valve ismounteddirectly on the cylinder. The exhaust air from the chamber of the cylinder enters

the blocking valve, which in this condition is closed. This condition is generated by the effect of the spring and the

pressure from the compressed air inside the cylinder, which acts on the poppet pushing it upwards, favouring the

closure. The poppet has no possibility to descend so the C/A connected to inlet 1 cannot pass. The valve has the

function of a 2/2-way NC valve.

Pos. B

valve in actuated position, presence of pilot signal.

The C/A exiting the exhaust chamber of the cylinder enters the blocking valve through outlet 2, passes the

depressed plunger and exits from inlet 1, continuing on to themain valve where it can be exhausted. To achieve

the passage from outlet 2 to inlet 1 it is necessary to activate the control piston of the blocking valve through the

pilot signal 12. The pilot signal 12, acting on the control piston, moves and opens the poppet.

The diagram illustrates the connection of a double acting cylinder with an intermediate stop. The C/A coming

from the 5/2-way solenoid valve cannot enter the inside of the cylinder as the blocking valve is closed, likewise

the exhaust air cannot leave the cylinder due to the other blocking valve which is also closed. By activating the

3/2-way NC solenoid valve, pilot signal 12 is received by both blocking valves. The poppet of each blocking valve

is depressed and opens the passages from 1 to 2 and from 2 to 1, thus allowing themovement of the cylinder.

In theabsence of thepilot signal 12, the spring repositions thepoppet,which closes thepassages, and theblocking

valve is in the rest position.

112

CAMOZZI

VALVES