Kennicott Water Softener Co
of Wolverhampton
and of Imperial House, Kingsway, London WC2
1912 John Thompson exhibited at the International Engineering and Machinery Exhibition at Olympia. Items shown included a water softening plant on the Kennicott system at work on the stand[1].
By 1922 was a subsidiary of John Thompson Water Tube Boilers Ltd
Sometime in the late 1920s Kennicott Water Softener Co was treated as a separate subsidiary, alongside the other 4 limited companies subsidiaries of John Thompson
1929 Annual meeting of the associated companies of John Thompson Ltd also included Kennicott Water Softener Co Ltd[2].
1950s An advert referred to John Thompson's 16 subsidiary companies including:
John Thompson-Kennicott Ltd - “For over half a century” manufacturers of water treatment plant for all purposes. This seems to be mainly for water going into boilers but includes "clarification and filtration plants for potable purposes".
1970 Clarke, Chapman and Co took over the Thompson Group with the support of the Industrial Reorganisation Corporation [3].
1977 Clarke Chapman became part of the new company NEI
1994 Thompson Kennicott Ltd was a subsidiary of Rolls Royce Power Engineering[4]