Pigging Used in Hygienic (or Sanitary) Applications
If you drink lemonade, cola, other soft drinks, wines or spirits, or use shower gel, shampoo, conditioner or deodorant, eat ready meals, chocolate, pickle, sauces, feed your dog or cat pet food, or use paints or coatings, then you have almost certainty used something that’s been “pigged”!
Pigging (also referred to as product recovery) is a well-established technology. It is a technique of recovering liquid or wet product that remaining in the pipeline during changeovers. It delivers a wide array of benefits and gives a high return on investment (ROI) with rapid paybacks.
But, how does the technology work exactly?
Pigging System and Components Explained
To get an idea of how pigging works we’ve created a new video of an HPS pigging system in operation. The video gives a step-by-step sequence of pigging, features some of the parts and components of the system and what they do. This includes the pig detector, pipelines, control software, receive station, launch station, housing, various valves, supports and fittings and most importantly the pig.
In the video, the operator begins the sequence by transferring the blue liquid with medium viscosity through the pipelines. The blue liquid is just for illustrative purposes – this could be anything from very low to more viscous liquids such as honey.
Following the transfer of the product, the operator uses the pigging control software to start the pigging sequence. The system is controlled by PLC’s, with either HMI or SCADA systems. The pig is then introduced into the line, and as it travels through the line it recovers the liquid which is then forced to the destination tank. At the end of the cycle, air returns the pig from the receiver to its housing. This is confirmed by the illuminating red LEDS on the pig detector, which provide a visual indication of pig presence.
Example of a Single-Pig System
The system captured in the video is a single-pig loop system, which is housed at our HPS head office in Nottingham, UK.
The single-pig system is the most common type of hygienic (or sanitary) pigging system, Normally, the product is pushed from the source to the destination (either filling machine or another storage vessel). However, in the case of the loop system the product is pumped into the line, and then pigged back to the same storage tank.
While single-pig systems are the most common type of system, they aren’t necessary suitable for some types of applications such as beer and wine. Here’s a useful page which illustrates the the different types of pigging systems.
Pigging Automation Increases Operational Efficiency
While some basic, less complex pigging solutions rely on manual selection, most pigging systems are either fully automated or semi-automated.
In the video, the single-pig system operates independently with fully automated process control. This ensures exceptionally high levels of safety, reliability and overall efficiency.
Generally, pigging systems that are automated are easier to run, and they lower the chances of human error because they operate without manual intervention.
Flexibility of the HPS Process Pig
The layout of the system features numerous bends and curves along the pipeline. This was a key requirement in the design of the pigging system. This is so we can demonstrate the flexible nature of the HPS pigs, which enables them to navigate 1.5 D – 90° bends, while still maintaining full body contact and efficiently recovering product.
We’ve included transparent sections on our demonstration single-pig system to allow observers to clearly see the product being transferred, and the pig itself recovering the blue liquid from within the pipe.
It’s important to note that seeing the pig isn’t always easy (even with the transparent sections), as the speed at which the pig travels is usually very fast. In fact, 10 metres per second is not unheard of.
Why Choose Pigging
As well as delivering financial savings and a high ROI, there are many other benefits of incorporating pigging into new and existing plants and pipework.
Our pigging solutions recover up to 99.5% of the product from the line, which is unmatched by anyone in the process pigging industry. As you can see from the video, the pipework is clear of the blue residual liquid without any traces of the product remaining. Because pigging recovers this product from the pipelines (instead of wasting it), it’s one of the best ways to increase product yields in liquid processing.
As well as saving significant amounts of product and improving yields, pigging also reduces water consumption and the use of cleaning chemicals. At the same time, it reduces overall waste and associated disposal costs and as such the environmental benefits of pigging are substantial.
Find Out More
Thanks for watching our latest video. We hope you’ve found it very useful.
If you have any questions about the video, or alternatively if you require more information about pigs and pigging systems, please contact HPS, or your local agent or representative.