What is the function and operation of the monitor?
A quick recap of the previous post ①
If asynchronous operation (one side does not close) occurs, the primary side air will flow into the exhaust port and " air leakage " will occur.
A quick recap of the previous post ②
If you continue to operate without noticing the failure,
Failure of both discs may lead to non -stop of the press .
This was the caution when the double valve failed .
Solve the anxiety of valves without monitoring devices!
That is the double valve with monitor (monitoring device).
Since ROSS launched the first double valve with a monitor (monitoring device) in 1954 ,
We have developed various monitor valves.
This time, we will introduce the operation and structure of the "EP monitor" (Electro-Pneumatic), which is most widely used in Japan.
The EP monitor has an EP spool built into the monitor unit.
When the power is turned off, the spool maintains its neutral position with the force of the left and right springs.
The body has independent left and right EP channels, and when the valve body opens, the EP channels are pressurized with supplied air.
Normally, the pressure on the left and right is balanced, so the EP spool maintains its neutral position.
In the figure below, asynchronous operation occurs and only the A side is open. Then, air is pressurized the EP flow path on the A side, moving the EP spool to the left. Movement of the spool breaks the contact of the microswitch.
The microswitch cuts the energization to the solenoid coil = the monitor detects asynchronous operation. At this time, the valve enters the restart prevention state and outputs a failure signal at the same time. Even if power is supplied in this state, the valve will not operate. (The valve does not operate even if the two-hand push button of the press is operated.)
Compare features here!
Single valve vs non-monitor double valve vs monitor double valve
From a legal point of view, the merits of monitoring are effective as risk reduction measures!
ROSS's double valve is easy to replace with a monitor!
