HpE Process In-Line Mixing Skids

Continuous in-line mixing of food products that by their nature have such a wide range of physical properties such as viscosity, Specific Gravity and temperature in an industry where process requirements not only vary from product to product, but also from recipe to recipe is an engineering design problem for anyone.

Making such systems hygienic and suitable for CIP is even more difficult.

Typical problems:

• Piston dosing pumps are not suitable for CIP and are only suitable for low viscosity products
• Pulsating flow from rotary lobe or piston pumps requires longer mixing elements to compensate
• In-consistent product mixes − Many products shear thin under stress and can ‘slip’ inside rotary lobe or twin-screw pumps meaning that flow and pump speed are not proportional & flow is difficult to predict. In some cases (such as chocolate) slip causes damage / separation of the product before mixing is done and adversely affects the final mix
• Selection on in-line mixers is a fine balance between introducing enough shear to ensure complete homogenisation and over stressing the product
• In-line mixers can be shorter and will cause less shear if the flow streams are mixed without pulsation
• For CIP mixing elements must be fully welded & polished to be fully cleanable
• Current systems need expensive flow meters and PLC control to overcome these issues

HpE bring together 2 world class giants in their respective markets when we design skids. Our easy to use mixing skids allow users to simply select the ration ingredient pump speeds to match the ratio of ingredients that the recipe requires’ then press start.

Customers get a consistent and repeatable mix of products that is flexible enough to cope with the ever changing & fickle consumer demands,
They don’t need mass flow meters, or plc’s to control, but both are available for more complex systems.

How do you achieve this?

1/ The pumps: Our new Wangen MX pump is a fully hygienic progressing cavity pump that, uniquely has a stator that is a constant thickness through its length. This solves key problems with traditional PC pump design:

• Rubber expands 15 x more than stainless as temperature rises − in traditional designs, the thickest part of the stator expands more leading top increased wear & deterioration
• Rubber flexes under differential pressure − in traditional PC Pump design, the thickest and most flexible part of the stator is also the sealing part. The limits maximum pressure per stage to about 6 bar, where the MX pump achieves 10 bar per stage
• A constant thickness stator means that we can fit a heating jacket that provides a constant transfer of heat to the product chamber
• The MX is suitable for CIP and so our mixing skids can be used for different products
• Using servo motors to drive the MX pump gives dosing/metering accuracies close to those available on piston pumps that lobe and twin-screw designs can’t touch
• The MX can work with products ranging from 1- 150,000 cps

2/ Primex are experts in the field of in-line mixing of food / pharma products and also heat transfer.

In-line mixers can introduce or remove heat from a product stream without the need for plate heat exchangers [which can’t work on high viscosity products and are difficult to clean] or excessively long shell & tube units.

• The mixing elements are fully welded and electro-polished making them the cleanest available
• Primex design units are a task − they are tailor-made and never a compromise
• Supplied with or without heating/cooling jackets
• Can have up to 4 Injectors in a single housing
• Intelligent design and pulse free flow allow us to make shorter mixers, minimising waste