This method of substrate pretreatment is the most popular due to the efficient way it processes parts continuously. As the name implies, this process employs the use of a pump and piping that transfers chemical solution from a reservoir tank to a set of risers. Attached to the risers are nozzles which impart a "jet" or "swirl" of solution onto the parts that physically, as well as chemically, removes soils or produces the conversion coating on the part substrate.

• High efficiency levels of cleaning and conversion possible
• Recirculating action keeps solutions that contact the part fresh
• Process times can be shortened
• Temperature may be reduced resulting in possible energy savings
• Chemical concentration can be minimized
• Best option for high volume production

This method of pretreatment employs the use of an electric motor to power a pump providing pressurized solution through a heating coil to a hose and hand held wand assembly. The heat is provided by an oil or gas fired burner to a heating coil that is part of this stand alone system. Cleaning, phosphatizing, and rinsing chemicals are introduced, individually, into the water supply by way of a chemical injection system upstream of the heating coil.

Typically, these hand held systems are best suited for finishers that fall into one of these categories

• Large, heavy, or bulky fabrications
• Large products post assembled
• Custom coaters

Advantages of Spray Wand Systems

• Low capital cost
• Handles hard to clean work pieces
• Suited for low volume batch processing
• Will work on bulky, odd shaped parts

Mesh belt (belt surface conveyor) washers are ideal for cleaning parts that cannot be suspended from an overhead monorail conveyor system.
In contrast to the continuous overhead monorail conveyor types, the belt surface conveyor is a conveyor where the product rides on the top surface of the belt. A belt surface conveyor can handle a wide variety of parts. Belt conveyors can handle parts ranging from less than a pound to hundreds of pounds. A surface belt conveyor simply consists of a plastic or wire mesh belt of suitable width running over a drive and idler pulley. The belt is driven between two side frames. A belt surface conveyor provides for continuous product processing with no product stopping or accumulation.

Often referred to as "tank cleaning", this method employs one or more tanks that hold solution in which parts are batch dipped or process dipped continuously via overhead conveyor. Batch dipping can be accomplished with an overhead hoist on rails that can lower an individual part or baskets of parts into the tanks. Conveyor systems can continuously dip parts into the tanks via elevation changes in the conveyor rail or with free rail hoists with power and free conveyors.

Advantages of this method include:

• Simple to maintain
• Low capital cost needed
• Prolonged chemical contact
• Odd shaped parts get complete contact with chemical solution