Sanitary pumps are specified in hygienic manufacturing industries where product specifications and regulations are at their tightest, and the slightest contamination is considered unacceptable. In order to maintain this level of sanitation, not only must the proper pump be specified, it must also be maintained and cleaned correctly throughout its service lifetime. Small sanitary pumps in the food & beverage, as well as pharmaceutical industries, will have specific manufacturer guidelines for cleaning in addition to general best practices for maintaining the requisite level of hygiene within the process. Although these guidelines vary by manufacturer, model, and process, this article provides a brief overview of the importance of performing regular and thorough cleaning, common practices and cleaning methods, and key hygienic features to look out for when selecting a sanitary pump for your process.
The Importance of Regular Cleaning
A stoppage in production due to below-standard sanitation and cleanliness is costly both in terms of wasted product and downtime spent addressing the issue, as well as the cost of servicing an improperly maintained pump. Cleaning and sanitation protocols are generally designed to prevent residual product buildup; if product is allowed to build up, microbial growth will occur, leading to contamination and spoilage of the bulk product. Ultimately this will result in the batch not meeting the sanitary requirements of set for that product and industry, wasting both product and the resources used to make it.
Regular cleaning can also help prevent the overloading of the motor especially in duties that handle viscous or high-density liquids, or duties where duties where laminating precipitates are a concern. In cases where cleaning is not properly performed, the motor will operate inefficiently, drawing more current and overheating, leading to increased wear of mechanical components relative to a clean pump.
Best Practices for Cleaning Sanitary Pumps
Small sanitary pumps in the food & beverage, pharmaceutical, and other hygienic industries are often cleaned using CIP (Cleaning-in-Place) or SIP (Sterilize-in-Place) methods. CIP is performed by circulating cleaning solutions (formulated using water, detergent, sanitizers, acids) through the pump and associated piping without disassembly. The goal of CIP is to remove organic and inorganic deposits on internal product-wetted surfaces including the pump casing, impeller, and seals.
The following is a broad overview of how CIP is performed for sanitary pumps; when handling cleaning agents (including acids and lye) always handle with great care, using rubber gloves and protective goggles, and referring to the instructions in the safety data sheet for the agent in question. Note that one should never directly touch the pump or the pipelines while sterilizing. The process generally follows these steps:
- Pre-rinse with warm (return) water.
- Alkaline wash (using caustic agent).
- Intermediate rinse using clean, fresh water.
- Optional Acid wash (ex. Low conc. nitric acid) — typically with warm solution.
- Final rinse with clean, fresh water.
The following is a brief guide to the formulation of cleaning agents at 70°C:
- 1% w/v NaOH (Caustic Soda) → 1 kg NaOH + 100 L water (or) 2.2 L 33% NaOH Solution + 100 L water
- 0.5% w/v HNO3 (Nitric Acid) → 0.7L 53% HNO3 + 100 L water
It is recommendable to avoid excessive concentration of the cleaning agent by dosing chemicals gradually. The flow of the cleaning agent must be adjusted to suit the process; for example, the sterilization of milk products or viscous liquids requires a higher flow of cleaning agent. SIP takes the cleaning process one step further by using steam or other chemical agents to sterilize the pump (remove microorganisms). After CIP is completed to remove macroscopic residue, the following SIP steps are performed:
- Circulation of steam or chemical sterilant.
- Hold at target temperature and pressure for a time period validated to ensure full microbial kill.
- Final rinse with clean, fresh water. The system is typically allowed to cool down to a temperature suitable for the product.
For sanitary pumps sterilized using steam, standard 3A protocols require the system design to automatically shut down if the product pressure reduces before atmospheric levels; the system cannot be restarted until sterilization is redone.
Key Sanitary and Cleanliness Features
In order to maintain cleanliness, it is ideal to choose a pump that both prevents the build up of product residue in the first place, as well as has features that make it easy to clean. Advanced hygienic design features in modern sanitary pumps for hygienic industries includes optimized internal geometry and profiled O-rings to prevent product buildup. The smoother the product-wetted surfaces are, the less product buildup will occur; the standard surface finish for sanitary pumps is <0.8 µm (32 µin) Ra (Roughness Average), achieved by mechanical polishing then electropolishing to remove micro-peaks in the surfaces. The use of computer-design for impellers and their retaining screws allows them to be manufactured to smooth, low-profile specifications, further preventing product buildup. The features mentioned above also make CIP/SIP more effective by improving contact with contaminated areas and reducing dead zones (hard-to-reach areas).
Contamination to pumps is also introduced when performing general maintenance — features such as front-loading mechanical seals in positive displacement pumps allow for inspection and isolated cleaning without dismantling the pump.
The first step in selecting the sanitary pump for your process is selecting the right supplier with the expertise and product base to provide the optimal solution. Partnership with Valutech ensures access to a strong supply chain and a product lineup to suit the needs of virtually any application. This article is a brief introduction to sanitary pump cleaning — for more information on available pump models, their features, and recommended cleaning practices, please contact Valutech here, or see the full sanitary pump lineup here.
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