According to the „Test laws for chamber filter presses“, a filter press must not only be secured on the operating side (by means of safety light barriers), but also on the rear side or made inaccessible (security technology for filter presses). Exceptions, for example, are non-automated filter presses in simple design, which do not have a plate shifter for an automatic filter plate shift. These filter presses are equipped with a 2-hand switch, which prevents intervention while the hydraulics are working. In addition, MSE filter presses are equipped with an intervention protection at danger points (above and below the stands). There are 3 different basic versions for rear protection:
SECURITY TECHNOLOGY FOR FILTER PRESSES
1) SAFETY LIGHT CURTAIN, INCL. REAR STEP PROTECTION
Depending on the specific equipment of the filter press, safety light curtains are installed on the sides of the machine. These are non-contact protective devices. A permanently installed rear protection tube including a tarpaulin on the operating side ensures the protection of the plant operators. This extends from the floor to hip height and prevents the operator from stepping backwards. The light curtain is mounted above the tarpaulin and switches off the plant immediately if it is interrupted. By interrupting the light curtain, all hydraulic functions are switched off immediately, whereby the filter press stops. The acknowledgement of the light curtain with the respective rope pull switch takes place via an emergency cord. The functions and thus the filter press do not restart until the emergency cord of the pull-wire switch has been triggered. The light curtain on the operating side is also included in the scope of delivery of the plate shifting system. The shifting of the filter plates is also switched off during reaching in according to the already described example, which optimally guarantees the safety of the operator.
2) MONITORED SLIDING DOOR
The protective guard consists of two-parts;, movable modules on the rear side of the press, which are equipped with an electrical, non-contact safety switch as access protection. By opening one of the two guards during running operation, the contact is interrupted, which immediately switches off the hydraulic functions and causes the press to come to an immediate standstill. Only after restoring the contact by closing the protective guards, does the filter press continue its respective functions by confirming on the control cabinet or by acknowledging the push button mounted on the frame.
3) MONITORED SAFETY DOOR
The safety door is located on the front side of the filter press. It is equipped with an electrical, non-contact safety switch as access protection. The safety switches are installed on the movable guards, such as sliding or hinged doors. These prevent the filter press from starting when the protective guards are open. When the door is opened during running operation, all hydraulic components switch off their functions, resulting in an immediate standstill of the filter press. Only after the contact has been re-established by closing the door can the functions – analogous to the protective guard – be continued by confirming on the control cabinet or by acknowledging the push button mounted on the door.