Especially in the chemical industry you will often find dangerous machines such as dryers and centrifuges. These machines are equipped with rotating parts that in many cases do not come to an immediate stop when switching off the power.
For protection, doors and hatches safeguard these machines. It should never be possible that one of the doors or hatches is open while the machine is still in motion.
Unauthorized access of personnel could lead to major injury or even death.
To ensure safe operation bolt locks can be installed on all main switches and door locks to be installed on all access points (doors, hatches etc.).
In combination with a time delay box it will not be possible to access the doors and hatches unless the power has been switched off and the full retention time of the machine is covered.
The quantity of switches and access points may vary and is always depending on the client requirements.
Bolt locks (SBL, DBL)
Door locks (SDL, DDL)
Time delay box (TDB E or M)
Key exchange box (KEB N-N)
During normal operation the main switch will be switched ON while all access points (doors, hatches etc.) will be locked closed.
Switch OFF the main switch and lock it by taking out key A. Insert key A into the time delay box. This will start the time delay unit and an orange indication will illuminate. Until the full retention time is covered key B will be trapped in the time delay box. Once the retention time is covered a green indication will illuminate and key B can be released. Once key B is released key A will be trapped in the time delay box.
To unlock the access points insert key B into the key exchange box KEB 1-3.
Take out as many keys C as required and unlock the access points.
This can be done in random order. Insert the keys C into the access points and open the doors or hatches. The key C is trapped as long as an access point is open.
To go back to the normal operation mode the same sequence has to be mirrored except for the retention time.