It all started with a customer enquiry: A pharmaceutical manufacturer needed a system for cooling blood plasma to -30 °C in a short, set period of time. L&R then developed a “plate freezer” that works on the principle of contact cooling and introduces the cold into the product very quickly. In the meantime, the second plate freezer has already been designed and built – a one-off production has become a (small) series product.

The task was: Bags that hold 6 to 8 litres of freshly collected blood plasma must be cooled to -30 °C for a set period of time in order to store it. The plasma is later used to produce substances that promote coagulation and vaccines, for example.

The L&R engineers quickly realised that this task could not be solved using the conventional method – cooling by circulating cryogenic air. Therefore, they decided on the principle of contact cooling and developed a system made entirely from stainless steel with two refrigeration cells, each with seven contact plates arranged one above the other.

The refrigerant flows through the plates. When the refrigeration cell is fully loaded, a cylinder extends so that the bags are placed against the contact plates with controlled pressure. In this way, the cold is transferred much more effectively and thus faster – so fast that it is called “shock freezing”.

In the meantime, this system has proven itself in practice, and shortly afterwards, L&R already received an enquiry from another manufacturer of pharmaceuticals for a similar task. The second plate freezer cools the products down to an even lower core temperature of – 65 °C. Here, the refrigeration and control technology is arranged in a decentralised manner, whereas in the first unit, all functions and assemblies are integrated in a compact housing.

This means that the new type of system has been added to the L&R range. Just like conventional refrigeration systems that work on the principle of air cooling, plate freezers are individually designed for the respective requirements.

As with the previously manufactured systems, the requirements of clean room systems (clean room class D) and the regulations for “Good Manufacturing Practice” (GMP) with the DQ, IQ and OQ documentation that is customary in the pharmaceutical industry can be taken into account. It also ensures easy, thorough and residue-free cleaning.

The plate freezers are operated via a touch panel that allows convenient parameterisation of control functions. The visualisation of the integrated measurement data recorder provides additional transparency. And because both the control cabinet construction and the PLC programming are carried out in-house, the plate freezers can also be optimally adapted to the individual process at the control technology level.

Chemical & pharmaceutical industries

System solution
Low temperature refrigeration system