pigging pipelines HPS

Avoiding the Common Mistakes and Getting Pigging Right

With over two decades of experience and a wealth of expertise in designing liquid product recovery (otherwise known as “pigging”) systems throughout the world, HPS have encountered a wide range of issues over the years.

In this blog article, we explore some of the most common mistakes that can occur in process pigging and, most importantly, how you can avoid them on your next project.

Please note, this blog is in relation to pigging systems for hygienic, sanitary and process applications such as food, beverages, confectionery, household liquids, pet food, paint, personal care products and so on.

Download our Free Guide to Hygienic Product Recovery (“Pigging”) for the Process Industries >>>

1. Contamination and Safety Issues Due to Solid Magnets

hps pig in hand
     The HPS pig contains a flexible magnetic silicone core

Contamination and safety issues usually occur when using pigs with solid magnets.

The problem with solid magnets is that they are susceptible to breaking free from the pig and shattering, jeopardizing the safety of people and equipment. To add to that, broken magnets also have the additional risk of product contamination. If this occurs, then the entire batch is considered unusable and most likely needs to be thrown away.

Some pigs for pipeline liquid product recovery also feature a solid magnetic strip along the spine of the pig. These can also be problematic as they can snap, and in some cases, the whole pig will break into pieces. Again, resulting in an unusable batch and safety issues.

The best solution is to avoid pigs that contain solid magnets or strips. Instead choose pipeline pigs that contain a flexible magnetic silicone core that will not shatter, fragment, or break free from the rest of the pig. Therefore ensuring safety and avoiding the risks of contamination issues.

2. Product Bypass

Over the years, we’ve encountered product bypass issues associated with using pigs that feature fins, caps or assembled pieces. A common problem with using these types of pigs is that effective cleaning between the fins or assembled pieces is extremely difficult.

That’s because each fin will let a small amount of product past. Over time, the product will gradually build up in the gap between the first and second fin. The product build up will then occur between the second and third fin, and so on. Product bypass then becomes a major issue and can seriously limit product recovery rates. Even if the pigging process is stopped before this can happen, the shape of finned pigs makes them more difficult and time-consuming to clean and maintain hygiene standards.

A further problem with finned pigs is that they are more susceptible to ripping or small pieces breaking off. This results in contamination issues. Even more so if they contain solid magnets. In addition, pigs that contain fins or assembled pieces are typically constructed with a spine usually of a small diameter, making the pig not as robust as other types of pigs. As a result, they will need to be replaced more frequently.

All these issues can be prevented by avoiding pigs with fins, assembled parts or caps. And instead using a pig that has a robust, one-piece, and full contact design such as the HPS pig. Here’s an article on choosing the right type of pipeline pig for your liquid processing operation or application.

3. Insufficient Preventive Maintenance

pigging system close up

Although many pigging systems (such as a HPS one) are robust and constructed for durability and reliability, they still require routine maintenance. Normal wear and tear will cause certain pigging system components to eventually need replacing.

A common issue that we’ve come across is that some companies do not have a maintenance schedule in place. Instead, they replace parts as and when they need them. In some cases, they don’t even get replaced at all. For instance, some don’t check the condition of their pigs often enough so end up using a worn or damaged pig. This seriously hinders the performance and efficiency of the pigging system, all for the sake of a quick check.

In the worst case, insufficient maintenance may lead to equipment failing, resulting in unplanned downtime that could have been prevented. Unplanned downtime can seriously harm a business in regard to productivity, revenue losses, business reputation and so on.

However, regularly scheduled maintenance, known as preventative maintenance, will maximise efficiency, reliability, and the longevity of your pigging system. It will reduce the chances of unplanned downtime as well as the expensive costs from unanticipated equipment failure.

Preventative pigging system maintenance can be as simple as having critical spares in stock and regularly inspecting key components such as the pig, valves and so on (here’s a video on how to check the condition of your hygienic (sanitary) pipeline pig). It may also involve having a maintenance programme or recurring service agreement in place.

4. Pigs Getting Stuck

Pigs getting stuck in the pipeline is extremely rare (especially for HPS pigs). However, this is not to say that it cannot happen.

Generally, if a pig fails to reach its destination, there’s a plausible explanation for it. It may be due to lack of propellant pressure and faults with the pipeline. There may be leakage from a pipe connection, or even an obstruction such as a closed valve in front of the pig. It may also be due to using a worn or damaged pig.

That’s why it’s important to choose a pigging system provider that has the expertise to properly design a pigging system. The issue of pigs getting stuck can also be avoided by regular maintenance and not using a pig that is worn, damaged or has exceeded the recommended usage.

5. Poorly Designed System

Pigging systems have many benefits such as increasing yields, cutting waste, speeding up changeovers, improving efficiency and so on. However, some companies that process liquids are failing to reap the many benefits of pigging due to a poorly designed system.

This can easily be avoided by choosing a pigging system provider that has the skills and knowledge to properly design a pigging system around your exact needs and requirements. Although the principles of pigging are straightforward, it takes a wealth of experience and the highest level of expertise to successfully design, implement and commission an effective pigging system that offers a wide range of benefits and delivers ongoing return on investment (ROI) and payback.

If you work with a specialist company such as HPS Product Recovery Solutions, you have the peace of mind that HPS are trusted throughout the world. Organisations large as well as small, including multinational organisations such as P&G, Unilever, Kraft Heinz, Coca-Cola, Nestle, Mondelez, Loreal and many others use our systems every day.

6. Inability to Navigate Sharp Bends or Travel Both Directionsbenefits of pigging systems

Over the years, we’ve encountered pigs that cannot navigate sharp bends while efficiently achieving maximum product recovery rates. In addition, we’ve also come across pigs that can only travel in one direction. This severely hinders pigging system design and process efficiency, particularly regarding automation. Using a pig that is one-directional usually involves complex return loops which are problematic or may even involve operators removing the pig manually and returning it to its launch housing, following the completion of the pigging process. This can be time-consuming, is not sanitary, it’s inefficient, tedious and poses a significant risk to operator safety.

If pigs cannot navigate bends this can also be extremely problematic. Especially considering that many pipelines in the process industries comprise straight pipes, bends and other complex areas that must allow the pig to travel through successfully as part of the pigging process. Some pigs may be able to navigate bends but not achieve good recovery rates due to the design of the pig, which then makes pigging less effective overall.

This problem can be addressed by using HPS pigging products and equipment. The HPS pig is fully bi-directional and typically doesn’t need to be removed from the system, except for maintenance and inspection. What’s more, HPS pigs are flexible and can easily travel around 1.5 D bends while achieving recovery rates of up to 99.5% (in some cases, even more).

7. Choosing a Pigging System that Isn’t Bespoke

Unfortunately, some pigging systems are designed using a one-size-fits-all approach. Therefore, they aren’t bespoke and designed around the precise requirements and needs of each customer. The problem being is that one-size-fits-all doesn’t work in the process industries. After all, every plant and process facility is different, so every pigging system needs to be.

The best solution is to choose a pigging system specialist that doesn’t offer an “off-the shelf” pigging system. Instead, they work closely with you to understand your aims, objectives, and infrastructure. They will then be able to design a fully customised pigging solution around your exact requirements.

The Solution to All of These Mistakes?

There is a simple solution to overcoming the above pigging mistakes.

That is to ensure you always work with a specialist hygienic (sanitary) pigging and product recovery company such as HPS. With over decades of experience in liquid processing, HPS provides proven pigging solutions which are the industry benchmark in liquid product recovery.

Our pigging systems deliver ongoing savings with remarkable ROI and payback. They also offer a wide range of benefits to companies that process liquids:

  • Remarkable product recovery rates and high product yields.
  • Significantly faster processing, increased uptime, less downtime, and improved product quality.
  • Decreased waste and waste processing, water, and cleaning chemical usage.
  • Quick operation and significantly reduced washout times
  • High-performance HPS pigs – no solid magnets, which improves safety and minimises contamination risks. Robust, long lasting, no fins, and can navigate 1.5 D bends.
  • Bi-directional pigs– which enables fully automated operation and eliminates the need to remove the pigs manually.
  • Bespoke pigging systems designed around the precise needs of each customer.
  • Ongoing customer care and support throughout the lifetime of your pigging equipment
  • Plus much more

Find Out More

If you have any questions about this article please email info@hps-pigging.com with questions.

Alternatively,  for further information about HPS pigging and liquid product recovery systems for process industries, then please contact HPS.

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