Fowler Associates Labs

Company Profile-- Spotlight on

John Chubb Instrumentations is located in Cheltenham in the UK. Cheltenham is on the British Isles between Birmingham and Bristol.

An Anglo-Saxon settlement, Cheltenham - possibly from Celtenhomme, 'the town under the hill' - was the site of a monastery as early as 803. Alfred the Great wrote admiringly of the peace of the settlement on the banks of the River Chelt, and by the 13th century Cheltenham was noted for its fairs and markets.
http://www.cheltweb.co.uk/

Why Cheltenham? John previously worked in Cheltenham and knew there were a number of good people in the area. Having family in Birmingham, Cheltenham and Bristol, he knew he couldn't go wrong with Cheltenham. John states that, "there are good technical and professional resources there, good communications by road and rail and a nice town with plenty of cultural activities of various sorts during the year."

The business of John Chubb Instrumentation is electrostatic measurements. This incudes the development, manufacture and marketing of instruments as well as test and consultancy work for customers.

John Chubb set up JCI in September 1983. John had worked in a variety of areas over the years - electrostatic aspects of dust collection, high power vacuum interrupters, cryopumping of hydrogen on helium cooled surfaces, Monte Carlo modeling of free molecular gas flow. With the aim to provide high quality, high performance instrumentation for electrostatic measurements as well as consultancy in electrostatics, JCI was formed.

John states:
"Electrostatic measurement was an area I had involvement with from time to time from my PhD (behaviour of airborne particles in corona discharge fields) though the tanker work at Culham Laboratory for the Uk Atomic Energy Authority and in the work in North Wales. I realised that although there was various instrumentation available for electrostatic measurements much was of poor quality with only a limited range of capability from any one supplier."

JCI first product was the JCI 101 electrostatic fieldmeter. This provided much higher useable sensitivity than was available elsewhere. Attachments were soon added to enable this basic electric field measurement capability to be used to measure charge, with the JCI 151 Faraday Pail, and to measure discrete voltages, with the JCI 148 electrostatic voltmeter. Starting in 1987, JCI developed the JCI 155 Charge Decay Test Unit. Work since then has been enhancing the performance, ease of use and facilities of instrumentation based on these early designs. All the product development work has been supported by a good deal of investigative work that has been reported at conferences and in published papers.

John states that, "Our products aim to provide the capability to people in industry and research to measure a wide range of electrostatic parameters with ease, confidence and good precision. Our products cover the need to measure electrostatic conditions (electric fields, charge, surface and volume voltage, surface and volume charge density) and to assess the suitability of materials (charge decay time and capacitance loading). Some instruments have been developed for use in adverse environmental conditions (JCI 131 fieldmeter, JCI 501 Lightning Warning System). We have not developed instruments that are already widely available, but on those that we feel provide approaches that are appropriate measurements. (For this reason we do not make any resistance or resistivity measuring instruments - there are plenty around and they do not provide the information needed to assess the suitability of materials!). Our instruments are used in a wide variety of industries all over the world by specialist and non-specialist staff and their performance is backed by a formal calibration service (see BS 7506: Part 2: 1996)."

John Chubb Instrumentation
Unit 30, Lansdown Industrial Estate
Gloucester Road, Cheltenham, GL51 8PL
Tel: +44 (0)1242 573347
Fax: +44 (0)1242 251388
email: jchubb@jci.co.uk

JCI Developments :

- Electrode configurations for magnetic movement and electrostatic containment of arc roots in high power vacuum interrupters.

- Studies of the variations of sticking coefficients and vapour pressure of hydrogen condensed on liquid helium cooled surfaces.

- Monte Carlo modelling of free molecular gas flow in complex vacuum systems

- Concept and demonstration of novel monitor for respirable size airborne fibres

- Development of electrostatic 'field mill' fieldmeters which do not require earthing of the rotating choppers

- Development of instrumentation for charge decay measurement

- Demonstration of comparable charge decay performance betwen corona and tribo charging

- Proposal of concept of 'capacitance loading' as an additional way to assess the electrostatic suitability of materials