Valve slashes energy use
November 1st 2007 Alfa Laval Unique MixProof valves and ThinkTop valve control units have helped Unilever UK increase throughput by 30%, make waste savings of about 10% and slash energy consumption by more than a third at its Marmite/Bovril production plant
Local process engineering specialist, T. Musk Engineering, carried out part of the revamp at the plant, installing 16 new vessels, alongside eight existing tanks, to be used for storage of processed brewer's yeast. The flow of product and CIP fluids between these tanks and other key elements in the production process is controlled by the MixProofValve and ThinkTop combinations which, in combination with a central processor, have enabled the process of filling, emptying and cleaning tanks to be automated.
The new equipment has generated substantial time savings and cut energy costs, water use and improved hygiene.
The basic raw material used in the manufacture of Marmite is spent brewer's yeast. This enters the factory as a slurry from which the cell content is first separated and then concentrated in an evaporator before being transported to the storage vessels. The mixture is passed through further filtration and evaporation.
Of the 24 tanks involved in this process, one is being filled, another is being emptied and a third is being cleaned using a CIP system built around Alfa Laval Toftejorg Sani Magnum rotary spray heads installed in each tank.
Unilever's engineers opted for Unique Mixproof valves fitted with Think Top control units. The valves are designed to enable two incompatible media to flow through the system without intermixing and are suitable for the job of isolating the product and CIP streams in the Marmite production process.
Controlled remotely using compressed air, each valve is normally closed with two plug seals forming a leakage chamber between them. When the valve is opened, the leakage chamber is closed enabling product to flow from one line into the other. Any accidental leakage flows into the chamber. The SeatClean versions installed at the Marmite factory enable the plugs and valve seat to be cleaned by means of seat lift during normal CIP operations. The valve has a balanced lower plug that absorbs pressure shocks or constant high pressures to prevent leakage and product mixing.
Each valve has a Think Top valve control and indication unit. ThinkTop employs a no-touch system which makes mechanical sensor adjustments unnecessary and ensures accuracy and repeatability. LEDs give a constant display of valve position, solenoids activated, setup and instant fault indication. More articles from Alfa Laval Limited: | 
