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Department of Chemical Engineering and Biotechnology

By Professor Allan Hayhurst, with thanks to Jim Thompson

Ron was born in Belfast in May 1932 and brought up there. In fact, he graduated locally from Queen’s University in 1953 with a degree in Electrical/Electronic Engineering. His Ulster accent was an attractively soft one. His portrait above emphasises his seriousness and has omitted his friendly smile, which enabled him to work easily with others. He then moved to England and married Patricia Constance Spong in 1954, with whom he had three children, Pamela, Carol and David. Initially he worked as an electrical engineer in Bristol at the Bristol Aeroplane Company, before moving to Chelmsford to work for Marconi and then to Northampton, where he worked at Plessey.  

In 1963 the family moved to Cambridge, for him to become the Technical Officer in charge of the electronics workshop in Chemical Engineering. He worked with one technician and later with two of them. Their work varied from solving many minor electronics and wiring problems to designing and building very major pieces of equipment. One example was that in 1964 he started work on the first radio-frequency quadrupole mass spectrometer to be built in the U.K. It was a success. Nowadays, but not then, such a thing would not be novel , i.e. it can be readily bought. His work was not confined to electronic matters. For example, he contributed much to the design of a sampling system to enable a flame at over 2000 oC and atmospheric pressure to be sampled into a mass spectrometer at a pressure 109 times lower. That sampling system was later copied and used in the newly invented ICP – MS (inductively coupled plasma for mass spectrometry), an instrument much used nowadays by e.g. geologists for analysing rocks and minerals. These activities were considerably extended by the use of computers in experiments. Given that the Department’s first computer arrived at the same time as Ron, the local tradition of developing new ways of doing novel experiments is a very strong one. Thus, Professor Chase writes: “Ron’s ingenuity, enthusiasm and willingness were extremely important in the creation of the interfaces between computers, and my chromatography equipment that was so critical for my research at that stage”. Examination of Ron’s publications shows the range of fields, in which he helped to invent and develop new equipment. Thus the radio-pill opened up fluidisation, not to mention studies of mixing. He was always modest about these achievements, which included a number of patents.  

Ron took the degree of M.A. and was promoted at a time when that was much more difficult than now. He quickly turned out to be a key member of the Department, being one of its nicest, most competent, and reliable members. If you had a problem, whether it was an electronic one or not, you dropped in on Ron for a chat. Thus, one former member of the academic staff expressed his gratitude to Ron by saying that, but for Ron, some of his former students would not have received their doctorates. Ron worked his magic quietly in the Department until he retired in 1992 to look after his wife, who suffered with kidney disease and latterly needed frequent dialysis. She died in 2006.  Ron died in December 2021 at the age of 89. He had been in and out of hospital with various infections for some time and had also been diagnosed with Alzheimer’s. 

Some of Ron’s publications, which have been traced: 

1.  R.M. Ormiston, F.R.G. Mitchell, J.F. Davidson, The velocities of slugs in fluidised beds, Trans I. Chem. E., 1965, 43, T209-T215. 

2.  F.R.G. Mitchell, Low power telemetry for circulation studies, J. Phys. E: Sci. Instrum., 1969, 2, 812. 

3.  A.N. Hayhurst, F.R.G. Mitchell, N.R. Telford, A quadrupole mass filter designed for flame ionization studies, Int. J. Mass Spec. Ion Phys., 1971, 7, 177-187. 

4.  D.S. Scotting, C.W. Cowsley, F.R.G. Mitchell, C.N. Kenney, Computer-controlled experimentation  Trans I. Chem. E., 1974, 52, 349-353. 

5.  R. Elsdon, F.R.G. Mitchell, Electrification of polymers, J. Phys. D: Appl. Phys., 1976, 9, 1445-1460. 

6.  D.F. King, F.R.G. Mitchell, D. Harrison, Dense phase viscosities of fluidised beds at elevated pressures, Powder Technol., 1981, 28, 55-58. 

7.  B. Cooker, F.R.G. Mitchell, R.M. Nedderman, Mixing in a helical ribbon powder agitator, The Chem. Engineer, 1983, 392, 81. 

8.  P.R. Fields, F.R.G. Mitchell, N.K.H. Slater, Studies of mixing in a concentric tube air-lift reactor containing xantham gum by means of an improved flow follower, Chem. Eng. Comm., 1984, 25, 93-104. 

9.   F.R.G. Mitchell, J.M. Proctor, E. Turnbull, An optical method of measuring particle mass flow rates, J. Phys. E: Sci. Instrum., 1984, 17, 183-184. 

10. F.R.G. Mitchell, A small bore flow detector for liquids, J. Phys. E: Sci. Instrum., 1986, 19, 153-54. 

11. F.R.G. Mitchell, A.A.P. de Alwis, Electrical conductivity meter for food samples, J. Phys. E: 1989, 22, 554-556. 

Additional comments from other CEB members: 

John Dennis: I’m saddened to hear this – another great member of the Department. 

David Scott: Ron was an excellent colleague, ready to help cheerfully. 

Malcolm Mackley: Ron was a true gentleman and an invaluable Departmental Technical Officer in an age when people like him were an essential ingredient in order to do experimental University research. Most research equipment in his era was 'handmade' in the Department and so people such as Ron were invaluable in terms of constructing Chemical Engineering research test rigs. Electronics was playing an ever increasing role in data acquisition and Ron was able to work effectively with both the mechanical workshop and the computer section. His gentle manner with everyone was consistent and kind and the equipment  the electronics laboratory produced was inventive, clever and worked! 

Nigel Slater: Ron most memorably helped me by inventing a “radio-pill” passive transponder, which we used to measure mixing times in an air-lift fermenter. The remarkable thing about this was that much later I encountered passive transponders in two very diverse settings. About ten years later I worked with the Silsoe Research Institute and they were working on passive transponders to remotely monitor cattle on farms, using essentially the same principles, and to tag dangerous herbicides, etc. Then, about twenty years later, a friend was involved in a company, making door locks for hotel rooms; the locks recognised a passive transponder carried by the guest and unlocked automatically; I thought this unnecessarily complex, until he reeled off all the information, which such locks could provide on room occupancy and use – for example to save energy.  So Ron’s work was impressively ahead of his time. 

Allan Hayhurst: Ron’s contribution was at least two-fold. His work developing novel electronics, the computerisation of collecting data and the chasing of “gremlins” in mal-functioning apparatus was one thing. However, he and Margaret Sansom (the H.O.D.’s Secretary) kept an unofficial eye on things and so knew, much better than the academic staff, e.g. if a particular research student was having difficulties. These latter pastoral aspects contributed hugely to the success of the Department and its research. 

Bob Skelton: He was a great help to me in my early days in the department. 


Painting of Ron Mitchell by his son, David Mitchell

© David Mitchell