Proto control manufactures various types of level switches, indicators, controllers for monitoring level of liquids like water, oil, chemicals and solids like powder, granules, flour, sand, etc. It is an electronic switch specially designed for sensing the level of approaching stockpile on stacker-reclaimer or material in hopper, in a silo and to provide an output signal, which can be used to initiate control actions. The sensor probe of the unit is suspended vertically at suitable height to fulfil the machine requirement and has an omni-directional sensing pattern to give a switching action to whichever direction it tilts. The switch is provided with an on and off delay to avoid nuisance tripping. This switch requires hardly any maintenance. Capacitance measurement is the most universal system suitable for almost all products, liquids, or solids. The change in capacitance caused by different levels between electrode and measured media or container wall is detected. The change in capacitance is converted into switching commands or standardized current signal [4-20 m amp] proportional to level for further processing. The electrode forms one plate of the capacitor and conducting vessel forms another plate of capacitor. In case of non-con-ducting vessel [e.G., plastic tank] where second plate is missing, as the wall is a real insulator, the second plate is formed by an additional auxiliary electrode, which is connected to earth. Advantages: this method is ideal as it is unaffected by pressure, temperature. It is rugged having low maintenance and comparatively cheap compared to ultrasonic or nucleonic level measurement methods.
