In large industries, manual mixing of chemicals into their exact quantities to get to a final product is always tedious and time-consuming. Mixing chemicals result in different mass, reactions and a completely different product with different chemical properties from the primary chemicals. PLC is also known as programmable logic controllers have been invented to aid with the process and have greatly enhanced chemical mixing processes in industries. PLCs are fed with control instructions, which once executed coordinates, the mixing process.
As simple as the process of chemical mixing may seem with the aid of a programmable logic controller, expertise is needed for efficiency. The process is, however, no rocket science as one can easily sail through by keenly following the process explained below.
A simple form of PLC consists of the input pipes, the mixing vessel, and the output. It is programmed in a way that it is able to conduct arithmetic, coordinate between switching on and off as well as timing. Below are the key components of a PLC and its operations.
The level switch. This normally indicates the chemical levels. There are two level switches namely the high level switch and the low level switch. Once the chemical gets to the high level switch, the motor is switched on and mixing occurs in the mixing vessel.
Proximity sensor. The sensor is used to detect other objects, which could get into the operating zone. It is fitted with an oscillator, which operates in response to the external object’s presence.
DC Motor. In the mixing vessel, the actual mixing occurs once the motor is put on by switching on the high level switch. Stirring occurs depending on the instructions fed into the PLC and stops once the set time elapses.
Control valve. Once the mixing is over, the PLC executes a command for input to occur into the control valves, which are linked to the liquid tank. The valve in the liquid tank opens once the chemicals fill up the upper tank to the level switch and the content spills into the third tank. The same happens with the third tank whose valve opens to fill up the subsequent tank as per the set time.