ST-67 sensor has been designed to control the level of solid biofuels (pellet, oats, corn, etc.) both in the tanks of heating boilers and in any type of grain silos where the maximum spacing of measurement sensors does not exceed3.5m For the level control to be reliable, the fuel stored in the container needs to be dry. The principle of operation of the device is based on determination of the solid biofuel level by means of properly spaced volume sensors. Diameter of holes for sensors Ø 30mm.
At the time when the level of biofuel in the tank decreases below the lower sensor, the device starts sending a voltage signal (230V) to the motor of the external feeder, until the bunker is filled up to the level of the upper sensor. Such operation results in continuous cyclic refilling of the fuel in the tank with no additional human interference.

Functions performed by the controller:
- Maintaining stable Pellet level through cyclic refilling
- Measuring the Pellet level with the use of properly spaced sensors

Equipment of controller:
- Network cable with a plug, factory-installed, length 2.5m
- Power supply cable for the external feeder's motor, length 2m
- Two sensors (capacity-type), factory-installed, each with the length of 2m
- Controlling device