Turbine meter generates pulses based on the Flow of product in the main pipeline header. These pulses are processed by the PLC for flow measurement of main product (SKO). Based On flow sensed in the main header, PLC will trigger a Start command for the Blue Dye pump (Motor) and also Open command for the solenoid (On – Off) Valves on the delivery header of Blue dye skid. Blue dye will then be injected into main product line as per a pre set ratio (say – 25 PPM) or by putting PD meter which will be connected to PLC.
For every pre determined quantity of SKO (say 500 Litres) flowing through the header, the PLC Shall permit the solenoid (On - Off) valve on the blue dye delivery line to be open for a given Length of time in order to dose required quantity of blue dye. The flow rate of blue dye is always a constant parameter based on the settings of the positive displacement blue dye pump. Based on this flow rate, PLC shall monitor the time duration for which the solenoid (On – Off) valve shall Be in open condition. Once blue dye is dosed as per pre set ratio, PLC shall generate Close Signal For the solenoid (On – Off) valve. Quantity of blue dye pumped by the blue dosed is determined By the fixed flow rate of the positive displacement Blue Dye Pump.
The dosing shall continue in cycles for every pre determined quantity (500 Litres) of the main product passing through the header. As the main product (SKO) flow rate increases, the blue dye dosing cycles will increase accordingly. Ratio and cycles can be changed manually through the PLC.
Pressure in blue dye line is maintained by back pressure valve and sensed by pressure switch.
Suitable HMI in the control unit shall be built to provide custom displays like Blue dye Motor Status, Solenoid (On – Off) Valve Status, Blue dye Agitator Status, Flow – rate of product in the main header, Quantity of blue dye dosed (based on no. Of times solenoid valve is energized) etc.
Blue Dye Dosing panel ensure correct amount of Blue Dye dispensed at pre defined quantity set in PLC. The HMI provide display of On/Off status of Pump / Agitator, On/Off Status of Solenoid Valve, Flow rate of Main Product, and Quantity of blue dye dosed based on no of time solenoid valve is energized.
The system operates under following two modes as per selection from Local HMI.
Auto mode operates for Ratio Control Mode as per Selection.
For Ration control, the flow of main product (SKO) through its Turbine flow meter (Pulse generator) is Fed as an input to the PLC system. Pulses are processed by the PLC for flow measurement of main product.
Blue Dye dosing panel ensure that a correct amount of Blue Dye is dispensed with respect to Main product at all times on line in a predefined ratio ( set in the PLC) throughout the load cycle.
When a pre defined quantity packet for main product passed then respective Blue dye SOV will be energized for a given length of time for a dosing of Blue Dye. On dosing of pre defined quantity for Blue Dye Product, SOV will be de energized by PLC.
The flow rate of Blue dye shall be always a constant parameter based on setting of the positive displacement blue dye pump. Based on this flow rate, time duration shall be decided and fed to PLC as set point for solenoid ON time.
The Cycle continues during receipt in frequently dosing of packets of qty.