Machine Washers

Question:
What method of cleaning is best for disassembled equipment and bench-scale production equipment for clean-out-of-place (COP) procedures?

Answer:
Machine cleaning is performed on clean manufacturing tools, disassembled equipment and bench-scale production equipment in clean-out-of-place (COP) procedures. A machine that is designed to meet Good Manufacturing Practice (GMP) requirements can provide rapid, reliable, validated cleaning while using minimum amounts of water, resources and space. Historically, "lab style" washers have been modified to conform to GMP requirements. More recently, washers have become available that meet GMP requirements with design features including:

1. A chamber that allows for minimal water retention and provides good drainage from cycle to cycle with a minimum of solution carried over in any inlet or outlet piping. Corners that carry a minimum of a 1" radius and all surfaces are sloped to the drain. Internal chamber structures have rounded edges with no threads or fluid entrapment areas.
2. No mechanical attachment required for the accessory racks with regard to the mating of inventory systems to the hydraulic circuit.
3. Spray headers are positioned on the top and bottom of the racks to provide the most efficient cleaning.
4. A documentation package to complete the validation and qualify the cleaning system.

A well designed machine washer requires GMP compliant procedures for best use. In this regard, a complete inventory of size, weight, and specific cleaning requirements for each part and equipment to be cleaned needs to be taken. Additionally, which parts and equipment need to be cleaned together have to be noted. Cumulatively, with this information, appropriate loading and unloading patterns can be established. The goal of a good loading pattern is to allow good spray and cascading solution contact and good drainage of the parts and equipment. Any opportunity for pockets of solution to fail to drain from parts or equipment in between wash or rinse cycles need to be eliminated. By designing multi-level loading patterns, efficient use of water, detergent and utilities can be achieved. Since loads for GMP cleaning can range from glass to plastic to stainless parts, the design of a loading surface should allow for varying weights. If horizontal drop-down doors are used in the washer, they can serve as both the integrated loading platform when open and can allow for better seals than vertical doors when closed. Vertical doors typically require the use of separate loading carts. For these reasons, horizontal doors are often preferred.

Once good loading patterns have been established with proper racking, the pre-rinsing, washing, rinsing and drying cycles must be established. This involves selecting the correct cleaning agents, temperatures and time for each cycle. By knowing the substrates and residues that need to be cleaned, the correct cleaning agent can typically be determined. Typically a high alkaline cleaner followed by an acid rinse is used. Other important washer design features that should be taken into consideration at this point include that the delivery systems allows for precise application of additives and that a set-up of drying systems are in place that provide complete coverage of every part of a load. Once the appropriate parameters have been established, cleaning programs using the machine’s Programmable Logic Controller (PLC) are set.

The advantages of using machine washers are faster cleaning of parts and equipment using less human labor, less space, less water and less cleaning agent than comparable manual cleaning. A disadvantage of machine washers is that they often require very special racks and correct loading procedures to assure reliable cleaning results on parts or equipment with complex geometry.

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