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In our latest case study, we’re looking at a recent project where we were asked to supply a high capacity solid transfer pump to a client who operated a facility which rendered animal products. They wanted a rugged, reliable unit which would pump a 50/50 mixture of water and dry solids made up of dry meat, bone and tissue solids at around 350L/min at 2 bar.
What is rendering and why do animal products need it?
All industries create by-products that need to be reused, reprocessed or disposed of. Animal production and slaughter is no different, and this kind of by-product presents particular challenges.
If not managed properly, animal carcasses would present a serious health and environmental risk to livestock and humans. Rendering businesses handle by-products from slaughterhouses and fallen stock – animals that died on farm.
Rendering pumps help make the material safe and suitable for reuse in a wide range of applications. In addition, renderers deal with catering waste and unsold animal products that could also become a health hazard.
In fact, up to half of every animal produced for food is not suitable for human consumption. Moreover, rendering is actually recycling. It reuses materials that would otherwise be discarded, and repurposes them for various applications such as fuel and livestock feed.
It's a highly sustainable solution to food waste - recycling meat processing leftovers for other essential uses and saving landfill space.
Recycling is fairly new, but this is a tradition that goes back centuries. Rendering animal by-products became a widespread and efficient practice in the 20th century meat industry. But it actually dates back hundreds of years to when animal skins provided shelter and clothing, and tallow from animal fat was made into soap and candles.
What do rendering plants do?
High capacity solid transfer pumps help convert animal by-products from the meat and livestock industry into usable materials.
What’s more, this is a large and growing sector. The European Fat Processors and Renderers’ Association, or EFPRA, represents the animal by-products processing sector in Europe. They are a leading authority on the regulation, manufacture, bio-security and nutrient value of processed animal protein and fat.
EFPRA members process 18 million tonnes of by-products each year to make it safe, stable and suitable for reuse. They employ over 15,000 employees and process raw material on approximately 400 lines across the whole membership.
Rendering is a cooking or drying process that simultaneously destroys pathogens, dries the waste animal tissue and converts it into stable, usable materials.
The process separates the fat from the bone and protein, and produces three main products: water, protein and fat. The water is treated and returned to the environment. The protein and fat are used in a range of products including animal and fish feed, biodiesel, biogas fuel and fertilisers.
What was the project brief?
Our client was looking to pump a 50/50 mixture of water and dry solids consisting of dry meat, bone and tissue solids at around 350L/min at 2 bar.
The mixture had a viscosity of around 50,000cPs which is similar to ketchup or mustard. In addition, the formulation of the liquid and its consistency meant that it flows slowly so a pump with a built-in hopper was required.
Having a hopper built into the high capacity solid transfer pump ensures that the mixture doesn’t clog and the hopper pump is not damaged through either dry running, or having oversized solids clogging the inlet.
Rendering pump hoppers can be customised for a variety of liquids and applications. They act as a first stage in the process, feeding the pump with more manageable pieces and making sure that mixtures thatdon’t flow are fed into the pumping mechanism evenly.
Hoppers are available in a variety of designs:
Bridge breaker
These are used to slice large solids found into more manageable pieces which can be accommodated by the pump without processing. Fluids which rat hole, prevent free flow or obstruct pipework often need breaking up and kept moving via the use of paddles.
Rat holing is a common flow problem where material becomes stuck in the rendering pump hopper. Rat-holing causes a funnel flow effect, where the material flows freely above the outlet, but the material that isn’t directly above it doesn’t move and sticks to the hopper sides. If this material can’t be shifted it leads to product being wasted and more downtime as the hopper pump has to be cleaned more often.
Auger feed
An auger is a flat spiral-shaped screw that runs from one end of the hopper to the other, controlling the flow and mechanically forcing the material into the pump inlet. It’s specifically designed for dry solids and sludge which don’t flow freely and need feeding into the pump. It’s an essential part for this particular rendering plant application.
Motorised wheel
When materials such as liquid mortar, resins, mud, blocks of fat or butter are pumped they can plasticise meaning they change shape rather than break up. This means that clogs form and block the rendering pump inlet. These need to be removed manually, again, resulting in more downtime. Manufactured from metal, a motorised wheel rotates 360°within the hopper to stop solids building up and clumping together.
Fitted with a seal quench
We fitted the high capacity solid transfer pump with a seal quench which is a device that applies unpressurised oil to a mechanical seal's outboard faces to keep them clean and free from contamination. This helps to maintain seal integrity. This was important as the hopper pump would be handling large solids up to 41mm wide at high concentrations.
Rendering pump speed is another vitally important factor during the pumping of solids. So we designed the pump to have a reduced pumping speed of 130rpm using the gearbox. This meant that the unit would suffer less wear and tear, and give many years of problem-free pumping to the client.
If you’re looking to pump a liquid that doesn’t flow, contains large amounts of solids and easily solidifies, a hopper-fed progressing cavity pump could be the best solution for you. To find out more, speak to North Ridge Pumps to see how we can help.
For more information on Robust New Pump For Animal Rendering Plant Cuts Downtime Case Study talk to North Ridge Pumps Ltd