SPRAY PRE-TREATMENT

For mass production, a spray type pretreatment plant can be designed. Here, components are hanged on a overhead conveyor; which passes through a MS/SS enclosure.
Specially designed spray nozzles are fitted on the pipes to form a ring around the component. Depending on conveyor speed and time required for chemical process; number of rings are placed one after another for each stage. Two stages are separated by a drip or drain zone; where sprayed chemical is allowed to drain off the component. The sprayed chemical is collected in the drain pan and further directed into the tank. This is again sprayed on to the component by chemical circulation pump.
The entire stage enclosure is fabricated out of MS or SS as per the requirement. The type of spray nozzle, it’s capacity, material of construction etc. changes from stage to stage. This is a totally automated process and man power is required only at the loading and unloading point. Further, since this is an automated process; it gives enhanced quality and uniform phosphate grain layer all around the component.

This is a conventional pre-treatment wherein the plant cost is less and is suitable for low volume production lines. The chemicals are stored in the MS/SS fabricated tanks. The components are placed in the baskets or cages and they are dipped in each process tank for pre-fixed period of time. The movement of the basket or cage can be either manual; with a monorail and hoist or automatic with a transporter system.
Since this is a manual or semi-automatic process; the quality of the phosphate grain layer is not uniform. Further, as chemical tanks are open; the heat losses from hot tanks are more. The chances of inter-mixing of chemicals from one stage to other can not be avoided, also because of dripping and splashing, losses of chemicals are also more. But, since the plant and running costs are low, it is suitable for low volume production. This is a conventional pre-treatment wherein the plant cost is less and is suitable for low volume production lines. The chemicals are stored in the MS/SS fabricated tanks. The components are placed in the baskets or cages and they are dipped in each process tank for pre-fixed period of time. The movement of the basket or cage can be either manual; with a monorail and hoist or automatic with a transporter system.