Closed loop coating system

Arcall's Closed Loop application system can be used to evenly apply an accurate quantity of an ingredient.

The base product is continuously weighed on entry to the tumble drum; this weight is converted by a PLC into control signals to operate a control valve. If weighing equipment is not available, then the required application rate may be input by the operator. The amount of liquid ingredient actually being applied is monitored, several times each second, by a mass flowmeter and the flow constantly adjusted to match the demand.

The employment of a mass flowmeter, in preference to the more common volume flowmeter, means that changes in fluid density have no bearing on the application rate.

The PLC is capable of holding numerous recipes, so keeping operator involvement to a minimum. Output signals are available to record the liquid usage, so allowing data acquisition to support the declaration, eg, 'low fat'.

The FQB spray gun used in this system has been designed for the food industry. Arcall has manufactured the FQB spray gun to meet the needs of precise application with little mist, or waste. Spray is created by the use of a minute quantity of air, atomising the liquid at the exit of the gun. This allows a low pressure fluid flow in the pipe work and reduces wear and inconsistency. With both positive opening and closing, each gun can be individually operated by PLC for accuracy control to less than 1%.