For those in the food and beverage industry, clean-in-place (CIP) systems are an important component of daily cleaning schedules. CIP involves several activities that combine to properly clean all, or part, of a process system without having to take the system apart. The CIP systems pump cleaning, rinsing and sanitising solutions through the same piping path as the product, in order to eliminate product soil from internal surfaces.
In this instance, soil refers to anything that should not be present in a clean vessel.
CIP equipment helps control, monitor and document the cleaning methods essential to producing a variety of products hygienically.
What cleaning agents are utilised in CIP?
In most CIP applications, caustic soda, phosphoric, nitric acids, sodium hypochlorite and peracetic acid are used.
Caustic soda is an alkali typically applied at 0.5% - 2% volume and reacts to fats in the soil to soften them before removal.
Phosphoric and nitric acid are commonly used in detergent formulations for scale removal - however they can attack the valve and pump seals so should be used carefully.
Sodium hypochlorite is inexpensive and is primarily used for disinfection due to its poor ability to remove soil. As the active ingredient of this chemical is chlorine, when it is highly concentrated can corrode stainless steel and attacks the seals and personnel.
Peracetic acid is an equilibrium mixture of acetic acid and hydrogen peroxide and is a powerful oxidizing agent with an oxidation capacity higher than sodium hypochlorite and chlorine dioxide.
When it comes to the pumps required for CIP applications, it’s important to understand what the process involves. CIP uses a combination of chemistry, temperature, cleaning times and mechanical force to weaken the bonds between soil and system surfaces. This ensures that cross-contamination between batches does not occur - maintaining the integrity of products. These CIP pumps are responsible for keeping product, cleaning chemicals and water moving through the system during each phase of cleaning. CIP involves the following steps:
- Push-out (optional): This stage involves pumping out residual product in the process lines. A product-recovery system is commonly implemented which avoids product wastage and reduces the amount of time and resources needed to CIP.
- Pre-wash: potable water, water-for-injection, purified water or re-use is pumped to remove the previous cleaning sequence. This step wets the interior surface of the lines and tanks, removes remaining residue, dissolves sugars and partially melts fat. This step also provides a non-chemical pressure test and is considered one of the most important steps in the CIP process.
- Caustic wash: This is the main detergent wash and removes proteins and fats. Where there is very heavy soil, the caustic wash may be dosed in two stages - with the first wash sent to the drain, whilst the second can be recovered and reused. This stage is done between 60 oC and 85 oC
- Intermediate rinse: potable water, water-for-injection and purified water is rinsed through the system again to flush out dissolved soils and flushes residual traces of detergent from the caustic wash.
- Acid wash: Run between 55 oC and 65 oC, this acid wash dissolves mineral scale from hard water deposits, protein residues and neutralizes the system pH.
- Final rinse: This again, flushes out residual cleaning agents.
- Air blow (optional): Removes moisture remaining after the final rinse.
- Sanitising rinse (optional): this may be required to disinfect or sterilise the process lines. It kills any microorganisms before starting the next production run.
Changing the flow velocity (pulsed flow) within these steps enhances the effectiveness of mechanical fluid action and shortens the cleaning cycle times.
Understand CIP pumps and their importance
It is the force of the supply pumps and fluid action that removes the unwanted substances throughout the system. CIP pumps should be sized to provide enough flow and pressure to maintain the turbulence throughout the piping circuit.
Proper pump selection in CIP applications is crucial as the action, or turbulence of the cleaning fluid through the process lines is dependent on the velocity of the fluid and flow output of the pump.
Global Pumps recommend speaking with a specialist who can calculate the precise flow rate needed to create the turbulent flow in your system. They will ensure the pressure and flow created, as well as the pump’s chemical compatibility, is the most effective. Besides this, the pump must be capable of providing enough pressure to overcome any friction forces and back pressure.
The pump must also be chemically compatible. Purchasing a pump that cannot handle the chemicals used, will result in greater downtime, high maintenance and repair costs, and ultimately affect your production schedule.
Common CIP pumps
The most popular CIP pumps considered are centrifugal pumps. Each of these varieties offers users peace-of-mind when handling tough chemicals.
These pumps offer high flow rates, have mixing potential and are relatively simple in their constructions. These characteristics make centrifugal pumps suitable for CIP applications. It is important to note that these pumps should be constructed in 316 sanitary stainless steel, with cleanable seals to ensure optimal performance. It is also important the pump elastomers are compatible with the product soil and cleaning chemicals.
Rotary love pumps work on the principle of a counter rotation between two pumping elements (rotors and rotor case). These pumps are commonly found in food grade applications, where hygiene is crucial for the integrity of the product. Lobe pumps can handle larger particle size, as well as low viscosity liquids.
Magnetic drive pumps are sealless, meaning the pump liquid is hermetically sealed from the drive end and the driving power is transmitted via magnetic force, using powerful synchronous magnetics. Their heavy-duty function makes them ideal for contaminated liquids and corrosive chemicals.
Need more information?
Looking for more information? Or want to chat to a pump specialist about your application? Get in touch with Global Pumps today! Our team understand how important reliability and durability in any food or beverage production business. We work with clients to determine the most efficient solution to their tough challenge.