It’s remarkable how such a simple key interlock system can provide such high levels of safety integrity.
In this image you can see 2 x Key Switch Interlocks in Stainless Steel enclosures, with hinged lids. This specification is ideal for applications where CIP (Cleaning in Place) is part of the daily clean-down routine.
This key switch interlock is wired to the machine isolation circuit as the primary isolator. When power is energised the key is trapped in the interlock. Turning the key, switches off power. Only then can the key be released to unlock and open the access control interlock, also shown in the image.
The Access Control Interlock is fitted to a door or gate on the machine guard. With the key absent, the device is locked and the door cannot be opened. It prevents access to potentially hazardous machinery while it is running. To open the gate or door, you must turn off the machine to get the key. Simple.