Frequently Asked Questions

Companies that process liquids use pigging systems because they significantly increase process efficiency, effectiveness, productivity, profitability and environmental sustainability. This is through increased product yield, reduced waste, less downtime, quicker changeovers, and less chemical and water consumption.

For example, pigging systems can transfer residual product into the final package, rather than disposing of it, so increasing yields and plant capacity, while reducing product waste and saving time, money and resources. Similarly cleaning a pigged line is quicker and uses less water and cleaning chemicals, so reducing waste further and improving operational efficiency.

Learn more about the benefits of pigging

In the process industries, the main purpose of pigging is to remove and, most importantly, recover residual liquid that remains in a pipe after transfer from one location to another. It is also used to reduce contaminations risks, speed up changeover times, increase plant capacity and improve safety.

In its simplest form, a pigging system consists of a flexible projectile with a diameter slightly larger than the pipeline that needs pigging. Water, other liquid, compressed air or gas, or even the product being processed is then used to propel the pig through the pipe and remove or recover the remaining product. For an overview of pigging, please see What Is Pigging.

A hygienic or sanitary pipeline pig is a specially-designed, flexible projectile, slightly larger than the diameter of the pipe it is cleaning, which pushes a product through a pipeline.

HPS pigs are made from materials that meet the requirements of FDA regulations (one of the reasons they’re ‘hygienic’ or ‘sanitary’). We also provide solvent resistant designs. They are ‘full contact’ which means they clean constantly, even when travelling around corners. These are tough yet flexible and extremely effective; product recovery is typically up to 99.5%.

Just about any liquid or wet product that can be pumped can be pigged. This includes very low and very high viscosity products. HPS has successfully designed, implemented and commissioned pigging systems for products including food, pet food, confectionery, soft drinks, water, wine, beer, spirits, shampoos, conditioners, body wash, bubble bath, toothpaste, deodorants, hairsprays, detergent cleaners, chemicals, paint, pharmaceuticals and many more

Yes. The flexible nature of HPS pigs enables them to travel through 1.5 D – 90° bends and still maintain full recovery rates.

HPS pigs will withstand temperatures of up to 250°C or 482°F without degradation. This means you can steam clean them if required.

Hygienic pigging systems and sanitary pigging systems are the same thing. Generally, people in the UK, Ireland and elsewhere that mostly speak British English, tend to refer to hygienic pigging systems. In the US, Canada, Australia, New Zealand and some other countries, people are more likely to refer to sanitary pigging systems. There’s no hard and fast rule though; the words hygienic and sanitary are sometimes used interchangeably.

HPS stands for Hygienic Pigging Systems. That’s the original name of our company. A lot of people refer to us as plain HPS because it’s easier to say. We’re happy with that. We’re also known as HPS Product Recovery Solutions because product recovery is the proper name for pigging.

Because there are many different variables involved in working out costings, it is not possible to provide standard pricing. However, here is an article on pigging system pricing and how to find out how much a pigging system costs. Pigging systems deliver a high return on investment and usually pay for themselves in less than a year.

HPS pigs are robust, reliable and specifically designed to provide as long a working life as possible. However, the actual lifespan of a pig varies based on factors such as the process, pipe material, and products being pigged. When you contact HPS about a pigging solution for your organisation, our experts will be able to advise you on the expected lifetime of your pigs. As a general guideline, HPS pigs are typically guaranteed for 30 kilometres or 18 miles of use.

All pigging systems need a method of introducing the pig (or pigs) safely in to the line and getting it out of the way when it’s reached its destination. This is the key function of pig launchers and pig receivers.

Because most HPS pigging systems are fully automatic, there’s no requirement for the operator to manually remove or load the pig. Usually the only time you’ll need to manually access a pig is for inspection and maintenance.

Pigs don’t propel themselves, they are pushed along pipes by liquids or gases. There is a range of different propellants used in industrial process pigging, including water, filtered air, nitrogen, carbon dioxide and other products.

The HPS research team measured the average speed of an HPS pig at 40.56 mph, or 18.14 m/s. However, the speed at which pigs travel through pipe lines depends on the product, pressure, process, pipe diameter, pipe length and a number of other factors. Many people are surprised by how fast pigs travel through pipes. Most pigging operations last just a few seconds, sometimes even fractions of a second. This makes the whole pigging process extremely quick, minimising interruptions to operations.

It depends on the process. Typically, an operator or automatic control system will send a pig through a pipe to recover product whenever required. This can be, for example, when a pump has emptied a holding tank, there’s a change of product, before CIP, or when a particular batch run is complete.

Yes. We fit pigging systems in existing pipeline processes, as well as new plants. Our engineers will design a custom solution that meets your precise needs and install it with minimal disruption to your business.

Usually the pipework in a hygienic pigging system is made of stainless steel with a highly polished internal finish. This ensures optimal levels of product recovery, sanitation and cleaning. While it’s feasible to pig systems utilizing other types of pipe materials, we’ll need to have a discussion to determine the best approach. Regardless of your system’s pipework, it’s essential that the infrastructure meets specific criteria. For detailed guidance on pipeline infrastructure for pigging, please refer to our article.

Yes. HPS Pigging Systems and Clean In Place (CIP) solutions are fully compatible. Because HPS pigs recover nearly all product within a pipe, CIP processes become significantly easier, less time consuming and require less water and CIP chemicals, while also reducing labour intensity.

What’s more, HPS designs pigging systems to be fully compatible with CIP systems. This means that HPS pigs and other pigging system components (including specially designed HPS sanitary ball valves) can themselves be cleaned in place.

We advise against using an HPS pig immediately after a hot washout or clean in place (CIP) operation. It’s best to allow the pig to cool before its next use. You can usually accelerate cooling by flushing the pig with water or suitable alternative cooling medium.

Yes. We provide fully customised pigging solutions to meet the precise needs of each of our customers, so nearly every system is different. There are various types of pigging system available, however most hygienic pigging systems we supply fall in to one of three basic categories: single-pig systems, tank-drop off systems, or double-pig systems.

While some simpler pigging solutions still use manual control, HPS pigging systems are either partly or fully automated. Automatic pigging solutions, controlled by PLCs with either HMI or SCADA systems, have a wide range of benefits. These include increasing process speed, productivity and overall efficiency.  In addition, automation also decreases the chances of human error, thereby enhancing safety.

The required pressure varies depending on the system. However, in most cases, the pressure needed to push the pig is typically lower than the product pumping pressure.

The terms ‘Pigs’ and ‘Pigging’ are commonly used throughout industry. The most common reason given for the origin of the term comes from the oil industry. This is where metal discs connected by a rod were propelled through oil pipelines to remove the build-up of paraffin wax on the internal wall of the pipe. The action of metal on metal were said to have made a squealing noise like a pig. However there are other reasons given for the name ‘pigging’.  One is that the letters are an acronym standing for “Pipeline Inspection Gauge”. Another is that pig simply refers to a solid object, in the same way as a ‘pig’ of iron or lead. Either way, the common term for the process of sending an object through a pipeline to recover product or clean the lines is called “Pigging”. Today, pigging products and services are the core business of HPS Product Recovery Solutions.

If a pig doesn’t reach its destination, there’s always a logical reason. Typical causes are lack of air pressure, pipeline faults, leakage from a pipe connection, or an obstruction such as a closed valve in front of the pig.

Contact our Customer Care Team and they’ll help you to find and resolve the fault.

HPS pigs have special properties that enable us to magnetise them. Our specially designed pig detectors, which fit to the outside of pipework, will detect the magnetised pig at either end of a line. These detectors are non-intrusive to the product line and can detect the pig’s magnetic field through stainless steel pipe. The detector signals are then used for tracking and control systems.

Many of our customers use specialist equipment, products and processes. If it’s a liquid, we can almost always design a system to pig it. We have a saying at HPS: “If you can pump it, we can pig it!”

Contact one of our experts to find out what is the best solution for your organisation.

There’s no clear-cut answer on how long a pigging system takes to install. That’s because every pigging system is unique and designed around the exact requirements and needs of each customer. However, as a rough estimate, a simple single-pig system with one launch and one receive return typically takes about 2-3 days for installation, covering electrical, pneumatic, and mechanical setup. For more complex solutions like tank drop-off systems, installation times may be slightly longer

Our streamlined integration process means, regardless of the system, plant downtime is kept to an absolute minimum. We’ll also work around your schedule and minimise disruption to operations.

No, installation time is determined by the amount of equipment being installed and the number of pipelines. The length of the pipeline has limited impact on the installation time.

Some pigging systems are not designed hygienically as in some cases it’s not required.

However, the majority of HPS pigging systems and components are designed hygienically which minimises cross-contamination risks and allows quick and efficient cleaning processes.

In addition to offering hygienic solutions tailored for the food and beverage industry, HPS extends its expertise to various other manufacturers. For instance, we cater to the paint and coatings industry, where hygienic pigging systems are implemented to mitigate the risks of microbial attacks and potential contamination, ultimately reducing the likelihood of costly product recalls.

The team at HPS have a wealth of experience and expertise in installing long pipe runs. For instance, we successfully implemented a pigging solution for an Australian bottling company, where the process pig travels over 3000 ft (just under 1 km). Additionally, we provided a product recovery solution for a bottled water company in Canada, where the bi-directional pig travels over 1 km.

Regardless of the pipeline length, HPS hygienic pigs will efficiently travel through pipelines and recover practically all of the product (up to 99.5%) from the pipe.

If properly designed by a pigging system expert and appropriately maintained, pigging systems will last an extremely long time. In fact, some of our very first systems are still in use after twenty years. That’s because HPS systems are highly effective, durable, reliable and long-lasting.

However, nothing lasts forever, so routine replacement of certain components such as pigs and seals will help extend the lifeline of your system. Pigging system maintenance is also essential to ensure your systems remains in prime condition and delivers optimum performance. At HPS, we recommend having a pigging system service plan which gives peace of mind and saves you money in the long run.

All pigging systems come with a warranty that lasts a year. In addition, the pig (or pigs) also come with a minimum usage guarantee of 30 kilometers or 18 miles of use (subject to terms and conditions). For many customers, we also offer pig usage software, which tells operators when the pig is nearing the end of its working life and needs replacing.

Automatic pigging systems are nearly always ‘closed loop’ systems that require no manual intervention. The pig resides in a special housing at a launch station (and sometimes a receive station), which allows the system to automatically introduce the pig to the line as and when needed.

As well as storing the pig (or pigs) when they’re not actually ‘pigging’, HPS launch housings are designed so that the pig can be cleaned and CIP’d without actually being removed. They are also designed so the pig can be introduced automatically into the process line as required by the pigging sequence.

Please note that even in automatic pigging systems, pigs need to be removed from time to time for maintenance and inspection.

Of course! As well as being extremely good at what they do, HPS staff are a friendly bunch and happy to discuss any aspect of pigging or product recovery with you. Just give us a call, fill in one of the contact forms or drop us an email. We would love to hear from you!