Keeping Pipes Clean in Hygienic and Sanitary Processing
Extremely high standards of hygiene are vital for companies that produce or process food or drink intended for human consumption. In most countries, the standards of hygiene demanded for pet food manufacture are also extremely high. A wide range of other industrial processes also require hygienic (often referred to as ‘sanitary’) conditions.
Maintaining a hygienic environment includes keeping the machinery that processes product, and in the case of liquids, the pipework or tubing that transfers it, in a safely clean condition. In food and drink processing, this ranges from the raw ingredients stages to the finished and packed products.
Here’s a look at pipeline and tubing cleaning in hygienic and sanitary processing environments, including design considerations, clean in place and the role of pigging systems.
Pipe System Design
Systems designed with hygiene and sanitary conditions in mind reduce the risks of contamination; whether it’s biological, chemical or physical. They are also easier to clean, disinfect and sterilise.
Most countries have strict guidelines on hygienic machinery design. For example, in the UK and the European Union, hygiene requirements for all food machines are currently covered by the standard BS EN 1672-2:2005.
In pipe systems, good design includes the use of appropriate materials. Hygienic pipes and tubes are usually food-grade stainless steel, but note that not all types of stainless steel are suitable for food or drink processes.
The pipeline system layout design must ensure that there are no areas of the pipework that could be difficult to clean or likely to harbour bacteria, waste products, physical contaminants, or even contamination by sources such as insects or rodents.
All pipes or tubes should be close-coupled and use appropriate joining methods, while welds must be to a high standard and use correct welding materials. They should also be sited to enable easy access for regular inspection and, if required, for repair. For ease of operation, pipeline bends are usually a minimum of 1.5D, although the optimum bend radius is generally dependent on the viscosity of the product.
Industrial Process Pipeline and Tubing Cleaning
To obtain hygienic or sanitary conditions, the pipelines or tubing needs to be flushed out, disinfected and sterilised. This is usually performed as a ‘Clean In Place’ or ‘CIP’ process (it’s called ‘clean in place’ because none of the machinery or pipework needs to be removed or dismantled for cleaning, i.e. it stays in place).
The CIP process usually consists of an initial rinse stage, often using water, followed by one or two specific chemical washes using detergents, strong alkalis or acids. After each chemical application, there’s usually an interim rinse to remove the remnants of the previous chemical or cleaning agent.
The precise nature of the CIP process varies between processes, applications and product being transferred. This is because different products and processes require different levels of cleaning, including length of rinses or washouts, cleaning temperatures, the types, strengths and amounts of chemicals used, and the order they’re used in. For example, while many processes use water for rinsing, water is unsuitable for use with certain chocolate products.
Pigging Before CIP
Pigging systems are primarily used to recover product from within pipelines, instead of flushing it to waste. However, pigging also makes the CIP process quicker, easier and more efficient.
To ‘pig’ a system, a solid projectile with a diameter slightly larger than the pipeline transporting the liquid is propelled through the pipe by pressurizing the pipework behind it. Instead of being flushed to drain, the liquid residue in the pipe is recovered: pushed by the projectile (pig) and forced to the destination filler or tank, or returned to source. It can then continue being processed along with the rest of the product.
The pigging process itself is extremely quick, and, because it removes nearly all residual product in the pipe, pigging a pipeline before the CIP process can significantly reduce the time CIP takes. It also reduces the amount of water and chemicals required. This is in addition to increasing product yields (or using less resource to achieve the same output) also achieved through pigging.
Using less water is a key benefit of pigging before CIP because it saves money as well as benefiting the environment. Similarly, reducing the use of CIP chemicals is important because many of the substances used are noxious and harmful to the environment (some extremely so). They are also potentially harmful to people which poses a safety risk. In addition, the chemicals and cleaning agents used can incur high disposal costs.
Pigging reduces changeover times which increases overall system efficiency. During changeovers the system is non-productive, so speeding this up results in less downtime, subsequent productivity increases and reduced labour requirement.
In hygienic applications, pigging is unlikely to replace CIP altogether. However, hygienic pigging and CIP processes can work together extremely well.
Pig systems are usually closed-loop, and during normal operation pigs are kept in specially designed chambers or housings. These also launch or receive the pig.
HPS pig launcher and pig receiver designs enable full CIP of the pig as well as the launch and receive chambers. The chambers are slightly larger than the pig, so enable liquid to flow around the pig to clean and sterilise it.
HPS hygienic pigs can withstand temperatures up to 250 degrees Centigrade or roughly 482 Fahrenheit. HPS pigs can also withstand certain CIP chemicals (however if you already have an HPS system, please contact us before changing any chemicals or cleaning fluids you use).
While some or all of the CIP process can be automated, so can the pigging process. Pigging automation increases overall process speed, productivity and efficiency. It also enhances safety and reduces the chances of operator error. There are different levels of automation available, and pigging system automation can be standalone or integrated with the rest of the CIP process.
Find Out More
To find out more about hygienic or sanitary pipeline cleaning technology, product recovery and pigging, then please get in touch.