10th May 1937. Yes We ‘Can’.
Today in 1937 saw Britain’s first canned, frozen food, in the shops, asparagus, from Smedley’s of Wisbech, Cambridgeshire.
The principle of refrigeration simply put : Liquid evaporates and absorbs heat just as alcohol (after-shave) on the skin feels cold and evaporates at room temperature, as it absorbs heat from the skin.
Code for diagram of a fridge on the right:
A. Liquid Ammonia boils and vaporizes.
C. Ammonia becomes liquid at high temperature.
In days past pure Ammonia which boils at -27F was used which when compressed heats up and then in the coils, the gas dissipates its heat and the gas then condenses into a liquid at high pressure.
This then flows through the expansion valve a small hole. On the other side a low pressure compressor sucks gas out.
The liquid ammonia boils and vaporizes and the temperature drops to -27F making the fridge cold. The cold air is sucked up by the compressor and the cycle begins again.
Since antiquity mankind has been freezing food against corruption, with Ice-Houses, a feature of the big houses from the 17th century, where winter ice was stored in external underground chambers.
The first known artificial refrigeration was demonstrated by William Cullen in Glasgow 1748, by letting Ether boil into partial vacuum, but no practical use was resulted.
By the 19thc Michael Faraday was heating Hydrate of Chlorine in a sealed bent tube and placed the end of the tube containing the chemical in a hot bath of 100 degrees and the empty end in ice water of 32 degrees both on the Fahrenheit scale.(1)
A faint yellow atmosphere developed and filled the tube and after some time a yellow liquid formed in the cool end of the tube. This was liquid chlorine and when Faraday broke the tube, shards of glass flew all over and the yellow liquid vanished.
Faraday concluded that energy had been transformed in heat form to change the state of matter of chlorine. The absorption of heat had cooled the surroundings, which is the basis of refrigeration, a concept which is important in Thermodynamics.
The problem with pure Ammonia is it highly toxic for domestic purposes and CFC.s were used. However these affected the Ozone Layer so these have been superseded by HFC.s.
Smedley’s was founded by Evesham born, Samuel Wallace Smedley in the 1920.s who having left school at 11 worked as a street hawker selling oranges, but later developed canning of food.
The Company was sold to Imperial Tobacco in the 1960.s which had diversified into food and acquired Ross. By the 1980.s with mounting losses, as fresh food came into favour, Smedleys was acquired by Hillsdown Holdings, to morph into Premier Foods.
In 2011 Princes of Liverpool had acquired the business. Yet another example of small enterprises being swallowed by big capital, the way of the world!