The Merck, Sharp & Dohme plant in Hoddesdon manufactures liquid medicines for use by the company throughout UK and Europe.

These range from anti-depressives to anti-hypertensives. Liquid analogues exist for several of the tablet/capsule formulations which are manufactured at their Cramlington plant.

An important constituent of the liquid medicines is Sorbitol in solution. It is vital that there is no crystallisation of the Sorbitol and heating is therefore required to ensure a complete solution and also to maintain viscosity at an acceptable level.

Previously, heat was supplied by an electric convection oven. Eastern Electricity completed a detailed project appraisal, including on-site trials, which considered various alternatives including electric or steam ovens and individual heaters. The report resulted in the installation of Thermosafe induction heaters, highlighting the following advantages:

During on-site testing it was found that heating times were reduced from 48 hours to 15 hours!

This, combined with the lower electrical rating of the induction heaters represents an 86% reduction in energy consumption.

  • Low maintenance
  • Easy identification of barrels being heated
  • Heating of individual barrels
  • Automatic operation, no control required
  • Minimal surface heat losses, hence comfortable working conditions
  • Space saving
  • Flexible location

Conventional ovens transfer heat by convective hot air warming the barrel walls, with heat transferred by conduction to the contents. This is a slow, energy intensive operation, and inefficient due to the lack of effective exhaust heat recovery.

Induction heating delivers a uniform heating pattern direct to the drum walls with no hot spots. Heat up times are thus much faster than with ovens and energy consumption is considerably lower.

The Thermosafe Induction heater solution was also a much lower capital investment than alternatives, and is much more adaptable to changing future requirements.

The heaters are large induction coils wholly encapsulated in a chemically resistant cylinder, and offer IP66 enclosure protection. They can thus withstand high pressure hoses. This is of particular importance in areas where cleanliness is essential. The heaters in this application are sited immediately adjacent to a deionising water plant production water of high biological purity.