Cleaning in place, usually shortened to CIP, is a method of cleaning the interior surfaces of pipes, vessels, and process equipment without dismantling the system. Rather than taking a line apart after every production run, CIP circulates cleaning fluids through the installed pipework at controlled velocity, temperature, and concentration, removing residual product and biofilm automatically. The approach is standard practice across the food and beverage, dairy, brewing, personal care, and pharmaceutical industries wherever hygiene is non-negotiable and downtime is expensive.

CIP pumps make this possible. They supply, circulate, and return the cleaning solutions (water, caustic, acid) through the system at sufficient flow to create the turbulent conditions needed for effective cleaning. Without a correctly selected pump, the entire CIP cycle can fail silently: residues remain, microbial growth continues, and the next batch of product is at risk.

This guide explains the concept from first principles, walks through the cleaning cycle, and covers the pump selection decisions that determine whether your CIP system actually works. We draw on published pump engineering data to keep the technical detail grounded in what happens in real process plants.

What is cleaning in place?

The phrase "cleaning in place" captures the core idea precisely: the equipment stays assembled while the cleaning happens. Processing lines in dairy, brewing, beverage filling, and pharmaceutical manufacturing cannot realistically be disassembled after each batch — the effort would be prohibitive, and reassembly itself introduces contamination risk. CIP resolves both problems at once.

It is worth pausing on what "clean" actually means in this context, because it is not a single definition. Four levels are recognised in practice:

1. Physical cleanliness: removal of all visible dirt or contamination, verified by visual inspection.
2. Chemical cleanliness: removal of microscopic residues detectable by taste or smell but invisible to the eye.
3. Bacteriological cleanliness: achieved only with a disinfectant that kills pathogenic bacteria and the majority of other bacteria.
4. Sterility: destruction of all known micro-organisms; typically required in pharmaceutical and aseptic dairy applications via a sterilisation-in-place (SIP) step following CIP.

Standard CIP guidelines address the first three levels. SIP, using hot water, steam, or chemical sterilants, addresses the fourth, and is a separate (though related) process often performed immediately after the CIP cycle.

CIP is designed to remove residual product and biofilms from processing lines and equipment using turbulent cleaning fluid, without the need to dismantle the equipment.

One practical consideration that first-time specifiers often overlook: maximising product recovery before the CIP cycle begins is just as important as the CIP cycle itself. Mounting positive displacement pumps with ports in the vertical plane, for example, improves drainability and reduces the volume of residual product that enters the initial rinse — cutting both product loss and the concentration of soils the cleaning cycle has to deal with.

The five-stage CIP cycle

Internationally accepted protocol for CIP cleaning specifies a pipeline velocity of between 1.5 m/s and 3.0 m/s during all phases of the cycle. Velocities within this range have demonstrated effective cleaning across a wide range of hygienic pump types; as a rule, the higher the velocity, the greater the cleaning effect — though energy consumption rises accordingly.

The most effective cleaning processes incorporate five stages:

1. Pre-rinse with cold water. Potable or deionised water at ambient temperature, circulated for 10–15 minutes. The goal is to flush away the bulk of remaining product residue before chemistry is introduced. A well-executed pre-rinse makes the subsequent stages more predictable and repeatable — this is where a lot of specifiers get caught out, by underestimating how much work the pre-rinse can do.
2. Alkaline detergent wash (caustic wash). Typically a 2.5% solution of caustic soda (NaOH) at 70–95°C for 20–30 minutes. A surfactant (wetting agent) is commonly added to lower the surface tension of the detergent and improve its penetration into residue. This phase dissolves and removes organic matter — fats and proteins in particular.
3. Intermediate rinse with cold water. 5–10 minutes at ambient temperature. Removes residual detergent carried over from the caustic wash, preventing it from reacting with the acid stage.
4. Acid wash. Typically a 2.5% solution of nitric acid (HNO₃) at ambient temperature for 10–15 minutes. This stage targets proteins, mineral salts, lime, and other inorganic deposits that the alkaline wash cannot remove efficiently.
5. Final rinse with clean water. 10–15 minutes at ambient temperature, or until all traces of cleaning fluid are gone. In many systems the final rinse water is recovered and reused as the pre-rinse for the next cycle — the residual heat and trace chemistry from the final rinse makes the subsequent pre-rinse more effective.

A few important caveats. Cycle times, temperatures, and concentrations all influence cleaning effectiveness and must be tailored to the specific product being processed. Chemical compatibility between cleaning detergents and all product-wetted materials in the pump must be confirmed — not assumed. And rapid temperature cycling should be avoided: subjecting pump components to sudden thermal shock risks seizure or seal damage. Specialist cleaning chemical suppliers should make the final selection of detergents and disinfectants for each application.

The role of CIP pumps

Positive displacement pumps — rotary lobe types and circumferential piston types — are rarely used as the primary supply pump for CIP fluids. Centrifugal pumps generally handle the CIP supply role for each phase of the cleaning cycle, because they deliver the high flow rates needed to sustain turbulent velocity across the whole system at a competitive energy cost.

That said, the picture is not quite that simple. The introduction of twin screw pumps into hygienic processes has changed the calculus somewhat. A twin screw pump can handle both product transfer duties and CIP fluid supply and return within a single unit — a genuine two-in-one capability that reduces the number of installed pump positions and simplifies the piping arrangement.

The ability to operate across a wide speed range makes the twin screw pump capable of handling both product transfer duties and CIP, and it is widely used in the dairy, food, beverage, home, and personal care industries.

For product pumps that remain in the system during CIP, the standard recommendation is to develop a differential pressure of 2–3 bar across any pump not acting as the CIP supply unit, while rotating it at normal operating speed. A valve in the discharge line creates this differential pressure, with a bypass loop installed around the pump to divert excess CIP fluid that the pump cannot transfer at the required velocity.

During the CIP cycle, there must always be sufficient flow delivered by the CIP supply pump to ensure that the other pumps in the system are neither starved of liquid at the inlet — which would risk cavitation and seal damage — nor over-pressurised at the inlet because they are acting as a restriction.

One point the datasheet rarely tells the whole story on: seal face positioning matters for CIP effectiveness. On several Alfa Laval positive displacement pump designs, seal faces are positioned directly in the fluid flow path, ensuring they see full liquid velocity during the CIP cycle. This is not a trivial detail — a seal that sits in a low-velocity pocket may not be adequately cleaned even when the rest of the system is.

Pump types and CIP capability

All four main hygienic pump technologies — centrifugal, rotary lobe, circumferential piston, and twin screw — are rated for CIP and SIP capability when correctly specified. The choice between them for any given line depends on the product being processed, not the CIP requirement alone.

The self-priming centrifugal pump deserves particular attention in the context of cleaning in place. Tank emptying — getting the last of the product out before CIP begins — is exactly where a self-priming pump earns its place. The LKH Prime range is specifically designed for tank emptying and CIP return applications, and its verified CIP cleanability means it can also serve as a product pump when required. It achieves this through an airscrew and recirculation chamber design that allows the pump to evacuate air from the suction line without losing prime.

For CIP return duties specifically, the challenge is that the cleaning fluid returning from the system may carry air pockets, especially at the start and end of each cleaning phase. A self-priming centrifugal pump handles these mixed liquid-gas conditions far more reliably than a standard centrifugal pump, which would lose suction. Worth noting: the LKH Prime should not be oversized for the duty, because air evacuation capability diminishes below approximately 2,800 rpm — a constraint that matters when selecting motor and drive combinations. You can find the Alfa Laval LKH Prime in our centrifugal pump range.

With verified and effective CIP cleanability, the LKH Prime can be used as a product pump as well as for tank emptying and CIP return applications.

Pump selection for CIP applications: the key variables

Getting the pump selection right for a CIP application is more involved than it first appears. The right answer depends heavily on your system pressure and downstream configuration — there is no universal formula.

Several variables drive the selection:

Flow rate and pipeline velocity. The 1.5–3.0 m/s velocity target sets your minimum flow rate. Calculate the required flow from pipe cross-sections, then size the pump to deliver that flow at the system's total head. For a centrifugal pump, the duty point must sit within the pump curve at an efficient operating position — not at the extremes, where efficiency drops and cavitation risk rises.

Temperature range. CIP caustic wash temperatures of 70–95°C are common. The pump must be rated for the highest temperature it will encounter — and this includes the SIP step if sterilisation by hot water or steam is required (dairy applications, for example, typically sterilise at around 145°C). Check rotor clearance ratings for positive displacement pumps: many are specified at different temperature ratings (for example, 70°C, 130°C, and 200°C variants exist within the SRU rotary lobe family), and using a pump beyond its rated clearance temperature can cause contact between rotating and stationary parts.

Elastomer compatibility. This is where details matter most. EPDM elastomers resist most CIP detergents and are resistant to oxidation, acids, bases, and tough CIP conditions. FPM (also known as Viton®) offers excellent resistance to a wide array of substances including acids and oxidising agents. The choice between them depends on both the cleaning chemistry and the product being processed — an elastomer that handles caustic soda perfectly well may be unsuitable for the product itself. Always confirm compatibility for the full operating envelope, not just the CIP phase.

Mechanical seal configuration. For products that can crystallise, coagulate, or solidify when they contact the atmosphere — sugar syrups, for example — a single flushed mechanical seal is recommended to prevent the product from hardening in the seal area during and after the CIP cycle. Silicon carbide seal faces are recommended for abrasive media. For hazardous, high-viscosity, or high-temperature duties, double flushed seals may be appropriate.

Self-draining capability. All five major pump technology types are rated as self-draining when correctly installed. For positive displacement pumps, mounting with ports in the vertical plane maximises drainability and reduces product loss before the CIP cycle begins.

For process lines that run both viscous products and CIP fluids — fruit juice concentrate is a classic example — the twin screw pump and the circumferential piston pump each handle the dual duty differently. The twin screw can run at higher speed during CIP (where viscosity is low and flow rate demands are high) and slower during product transfer (where gentle handling matters). The circumferential piston pump, with its very small internal clearances, maintains high volumetric efficiency at low viscosities with medium to high discharge pressures — a combination that suits many food and dairy CIP duties well. Our DuraCirc circumferential piston pump is a strong example of this capability, and the SolidC centrifugal pump is designed for basic CIP solution supply and utility duties in less demanding applications.

A broader overview of our centrifugal pump range and our circumferential piston pump range can help you understand which technology fits your specific process best.

SIP, cautionary notes, and practical installation details

After the CIP cycle is complete, an additional Sterilisation-In-Place (SIP) process may be required when highly sensitive products are involved — pharmaceutical filling lines and aseptic dairy operations are the clearest examples. SIP inactivates micro-organisms that may remain after chemical cleaning, using hot water, steam, or chemical sterilants. In the dairy industry, sterilisation temperature is typically around 145°C.

A few practical points worth keeping in mind during both CIP and SIP operation:

It is common practice for pumps to remain stationary when live steam is present during SIP. The reason is that the steam's gaseous state and its distribution through the system can cause uneven temperature rise in seal components — running the pump under these conditions risks distorting the seal faces. Once SIP is complete, the pump should be allowed to cool sufficiently before restart at low speed (under 100 rpm) to remove any trapped condensate. A small volume of seal leakage on initial restart after SIP is considered normal and temporary — the seal faces re-seat as the pump returns to operating conditions.

Temperature cycling is the other major risk. Pumps and other equipment installed in CIP systems contain components that expand and contract at different rates. Subjecting them to rapid temperature changes — for example, introducing hot caustic wash immediately after cold product — risks thermal shock and potential seizure. Gradual temperature transitions protect both the pump and the pipework around it.

Products containing particulate matter (seeds, fibres, fruit pieces) require individual evaluation. Their physical nature presents an increased cleaning challenge; longer cycle times, higher velocities, or elevated pressures during the cleaning phase may be needed to achieve the required level of cleanliness.

How we can help

At Euroflow, we specialise in pump and process equipment selection for the dairy, brewing, food, beverage, cosmetics, and pharmaceutical industries across southern Germany. As an Alfa Laval authorised distributor, we support tank builders, plant engineers, system suppliers, and end customers in selecting and sizing the right pump for both product handling and cleaning in place — including CIP return duties, tank emptying, and dual-duty process lines.

If you are designing or upgrading a CIP system and need guidance on pump type, seal configuration, elastomer selection, or total system head calculations, we are the right contact. Our technical team can work through the duty conditions with you — flow rates, temperatures, cleaning chemistry, and product characteristics — and recommend specific Alfa Laval pump models backed by detailed sizing data.

You can explore our pump ranges directly: our centrifugal pump overview covers the full range of standard and self-priming options, and our guide to pumps in the dairy industry provides additional application context for CIP-intensive processes. Get in touch with us to discuss your specific requirements.