Weigh Feeders do a continuous weighing and controlling of bulk material feeding as per desired set point. Two single Point Load cells of required capacity are installed below Weighing Idler/rollers to get load applied on belt at particular area (i.e. silent zone) , which in turn connected to Load transmitter to convert it into 4-20mA output. In a second 30-40 weighments are done for bulk material, running for desired accuracy. Optical encoder is fitted on return/driven roller which generates 1000 PPR (pulses per revolution) of belt speed sensing roller. The optical encoder converts slow speed of the conveyor in to high speed pulses to get desired accuracy.
The microcontroller based weigh feeder controller receives the weight in terms of kg/m from Load transmitter and speed in terms of pulses/min from optical encoder.
It processes these two inputs received from the field and calculates the feed rate in the form of Tons per hour (i.e. TPH) also calculate the cumulative weight passed through the Weigh feeder.
Set point TPH and start command can be given from the 3 locations (i.e. Local Panel , WF Panel & Master PLC) based on the selection switch (i.e. mode of operation) provided on WF Panel, whereas stop command can be given from all the locations irrespective of mode of operation.The accuracy particularly depends on the calm tape operation and consistent material spread on carrying belt.There is a provision to adjust the Load cell height and to remove the material deposited on the conveyer (on line) to get better accuracy.