VISATRON VN215/87plus, operates in the same way as the VN 116/87plus as far as the tripping of an alarm is concerned.
However, it is able to additionally indicate the suction point with the highest opacity and thus the compartment in which the overheating damage has occurred.
Unlike the other types, the VN 215 series has a single-suction-tube system, each compartment being connected by a separate tube to valve box designed for 10 suction lines. All procedures are similar to those of type VN 116 series.
Normally, the compound opacity of the oil mist from all compartments will continuously be measured. If the opacity exceeds the damage check starting threshold a damage check will be executed. lf the differential alarm level is exceeded, an alarm causing the automatic stop of the machine or a speed reduction will immediately be tripped.
In contrast to the type VN 116 series, a search run will be continued. By closing the valves of certain compartment groups according to an iteration procedure and by an opacity comparison, the single-suction line can finally be determined which is supplied with oil mist from the compartment in which the overheating damage has occurred. For damage indication on the detector, the position of the valve which is still left open is used for indicating the damaged compartment.
In order to meet the high mechanical and electrical demands and to take account of the mostly limited space at the engine, all VISATRON oil mist detectors are constructed as packaged units by using aluminium cast, with the wear-resistant air jet jump, the vibration-isolated base plate for the metal-clad measuring unit with plug and socket connection as well as the electrical and pneumatically connections being erected on a solid cast iron plate. The suction tubes on the left and right side are connected to the valve box by two molded rubber flanges having no threads. The use of the particularly advantageous siphon assembly likewise allows a connection of the tubes of the siphon blocks without any threads.
All subassemblies including the valve box are provided with plug and socket connections and can, if necessary, be exchanged without the tubes at the engine having to be dismounted.