|This article does not cite any references or sources. (June 2012)|
Clean-in-place (CIP) is a method of cleaning the interior surfaces of pipes, vessels, process equipment, filters and associated fittings, without disassembly.
Up to the 1950s, closed systems were disassembled and cleaned manually. 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.
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 to people. 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.
Depending on soil load and process geometry, the CIP design principle is one of the following:
- deliver highly turbulent, high flow-rate solution to effect good cleaning (applies to pipe circuits and some filled equipment).
- deliver solution as a low-energy spray to fully wet the surface (applies to lightly soiled vessels where a static sprayball 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).
Elevated temperature and chemical detergents are often employed to enhance cleaning effectiveness.
CIP and groundwater sources
Originally developed for cleaning closed systems as described above, CIP has more recently been applied to groundwater source boreholes used for high end-uses such as natural mineral / spring waters, food production and carbonated soft drinks (CSD).
Boreholes that are open to the atmosphere are prone to a number of chemical and microbiological problems, so sources for high end-use are often sealed at the surface (headworks). An air filter is built into the headworks to permit the borehole to inhale and exhale when the water level rises and falls quickly (usually due to the pump being turned on and off) without drawing in airborne particles or contaminants (spores, molds, fungi, bacteria, etc.).
In addition, CIP systems can be built into the borehole headworks to permit the injection of cleaning solutions (such as sodium hypochlorite or other sanitizers) and the subsequent recirculation of the mix of these chemicals and the groundwater. This process cleans the borehole interior and equipment without any invasive maintenance being required.