Clean-in-place

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Clean-in-place (CIP) is an automated method of cleaning the interior surfaces of pipes, vessels, equipment, filters and associated fittings, without major disassembly. CIP is commonly used for equipment such as piping, tanks, and fillers. CIP employs turbulent flow through piping, and/or spray balls for tanks or vessels. In some cases, CIP can also be accomplished with fill, soak and agitate.^[1]

Up to the 1950s, closed systems were disassembled and cleaned manually.^[2]: 487 The advent of CIP was a boon to industries that needed frequent internal cleaning of their processes. Industries that rely heavily on CIP are those requiring high levels of hygiene, and include: dairy, beverage, brewing, processed foods, pharmaceutical, and cosmetics.^[2] A well designed CIP system is needed to accomplish required results from CIP.

The benefit to industries that use CIP is that the cleaning is faster, less labor-intensive and more repeatable, and poses less of a chemical exposure risk. CIP started as a manual practice involving a balance tank, centrifugal pump, and connection to the system being cleaned. Since the 1950s, CIP has evolved to include fully automated systems with programmable logic controllers, multiple balance tanks, sensors, valves, heat exchangers, data acquisition and specially designed spray nozzle systems. Simple, manually operated CIP systems can still be found in use today. However, fully automated CIP systems are in demand to avoid human errors, consistent results at reduced resources.

Depending on soil load and process geometry, the CIP design principles are as follows:

• deliver highly turbulent, high flow-rate solution to effect good cleaning (applies to pipe circuits and some filled equipment). The required flow rate can be calculated by considering fluid velocity minimum 1.5 m/s. The right flow rate can be calculated by using calculator.
• deliver solution as a low-energy spray to fully wet the surface (applies to lightly soiled vessels where a static spray ball may be used).
• deliver a high energy impinging spray (applies to highly soiled or large diameter vessels where a dynamic spray device may be used).^[2]

Elevated temperature, turbulence, circulation time and chemical detergents with additive are often employed to enhance cleaning effectiveness.