Camozzi Pneumatics Manual

Fig. 16

Isolation valves

Theseare valves,which canbe, added to theair treatment units asmodules andhavea characteristicallyhigh flow

rate as they feed the air distribution system. Their main task is to feed and exhaust the compressed air system or

part of system towhich they are installed. They are 3/2-way valves and can exhibit various types of commands.

Figure 16

Pos. 1

: at rest position the spring

raises the spool

upwards, the outlet port 2 is connectedwith the exhaust port 3

and the inlet 1 is closed.

Pos.2

: energizing thesolenoidcreatesanair passagewhich, byactingon thepiston,moves thespool

downwards,

allowing the passage of the compressed air from inlet 1 towards outlet 2, while the exhaust port 3 closes. The

spring

is now compressed.When the command signal is interrupted, the pilot air acting on the piston exhausts

and the spool is repositioned in the resting statewith help from the spring

Below are the different command types:

Figure 16

Pos. 3

: electric

Pos. 4

: pneumatic

Pos. 5

: manual (Lockable)

In themanual version, the valve is the bi-stable type (push/pull knob). This is equipped with a hole, allowing the

insertion of a lock so the valve can be locked in a closed position (maintenance mode). With the valve in this

position the operators are able to carry out maintenance and other work on the systemwithout risk.

When the valve is in rest position, the compressed air system is normally exhausted and all cylinder chambers

are connected to the atmosphere. With the activation of this valve a rapid pressurization occurs on the system

which could lead to sudden and uncontrolled movements of the piston/piston rods of the cylinders which could

cause damage to themachine structure or even injure operators in close contactwith the systemTo prevent this, a

so-called soft start valve can be added to the isolation valve. We examine soft start valves in further detail in the

following paragraphs.

CAMOZZI

AIRPRODUCTIONANDPREPARATION