Vibrating fork limit switches

The LFV and the LBV vibrating fork limit switches utilise piezoelectric measurement technology and exploit the damping properties of liquids and powdered bulk materials. The electronics of the LFV evaluate frequency changes while, in the case of the LBV, the rise or fall in amplitude determines whether a switching signal is transmitted.

The modular design of the sensors permits differing sizes and designs to be selected for the particular process. Threads of different sizes are available for both the LBV and the LFV sensors; the latter series can also be combined with tri-clamp tube attachments or flanges. If necessary, optional tube extensions or carrier wires allow removal of the vibrating fork from the housing in order to achieve a desired response height. Plastic, aluminium or stainless steel can be selected for the housings and cable screw connections. The switching electronics may be in the form of a contact-free switch, or a relay or transistor output.

In addition to the standard versions without approvals, the LFV and LBV series also offer devices that are ATEX certified for installation in potentially explosive zones. Versions approved by the WHG for preventing overfilling are also available.

The LBV sensors have been specially designed for containers with bulk materials or powdered media such as flour, wood pellets, plastic granulate or rubber. The piezoelectric measurement and symmetrical structure of the vibration probes ensure high immunity to contamination, depositing and external vibration effects. Pressure differences and eddies, as well as foam, gas or bubble formation, have no effect on sensor function or switching accuracy.