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Chilworth Technology Acquires John Chubb instrumentation (JCI)
Chilworth Technology Ltd, (CTL) is a leading provider of expert services in the field of process safety and electrostatics, currently with bases in 8 countries (including the USA and India), and its own worldwide reputation for excellence. In addition to process safety testing and consultancy, CTL already manufactures a range of specialist instrumentation, and is renowned for its expertise in the area of electrostatics. The JCI business therefore fits very well alongside that of Chilworth Technology, where it is expected that Chilworth’s direct presence, and experience in marketing around the world will lead to rapid growth. For the full press release see here. For information on electrostatics consultancy and the JCI product range see the above menu options. Further information on the full range of process safety testing and consultancy services from Chilworth can be found at www.chilworth.co.uk. Other process safety laboratory instruments can be found on our Chilworth Systems website at www.chilworth-systems.co.uk. "Tribocharging studies on inhabited cleanroom garments" This paper is published in J. Electrostatics 66 2008 p531-537 and is available online via: http://www.sciencedirect.com The test method used in the above studies is available on this Website. JCI 504 Lightning Warning System A full description of the system and its operation is presented in the user manual. "An Introduction to Electrostatic Measurements" "A Standard proposed for assessing the electrostatic suitability of materials" A document proposing methods for the formal calibration of electrostatic measuring instruments has been offered to British Standards. Charge calibration Control of temperature in JCI 191C Controlled Humidity Test Chamber Combined measurement of atmospheric and power line electric fields: A special version of the JCI 131 Adverse Conditions Electrostatic Fieldmeter has recently been supplied to 'Human Radiation Effects Group' at the University of Bristol. The frequency reponse of the fieldmeter was enhanced to -3dB at 70Hz with adjustments to the operational health system to avoid cross interaction between field and health observations. The new version Base Unit, the JCI 234, uses a low pass filter (-3dB at 7Hz) for direct measurement and display of quasi-contiunuous atmospheric electric fields and a bandpass filter followed by a precision rectifier for measurement and display of power line frequency fields. Company incorporation: As from 1 May 2006 John Chubb Instrumentation has become a Limited Liability Company (Company registration number 5978844). Business activities, location and contact addresses remain just the same as for JCI. Studies on Solvent Extraction (SX) plants: In January and in March this year further studies were carried out at copper mines in Laos and in Chile on electrostatic safety aspects of operating solvent extraction plants. It is hoped to report general conclusions on requirements for safe operation at the Institute of Physics 'Electrostatics 2007' Conference in Oxford, March 2007. Distributor for Taiwan:
"Electrostatic safety during solvent extraction"
"Large scale Faraday Pail JCI 247"
"Non-contact measurement of shielding and the resistivity of layer materials"
Update of JCI-Graph
"Measurement of charge transfer in electrostatic discharges" Electrostatic ignition risks and tank washing operations
Method for testing the electrostatic suitability of materials Tribo and corona charging comparison: T he studies have drawn attention to the point that that surface charge separated at tribocharging only comes to exert local electrostatic influence around 100ms or so after the end of the charging action - at separation of the surfaces. Thus in corona charge decay studies to assess the suitability of materials to avoid problems it is actually the voltage at this time that should be used for calculating capacitance loaidng values and to form the initial voltage for charge decaytime measurements. The decay of surface voltages before this time is hence only of technical interest - not of practical relevance.
Comments on methods for measuring 'Charge Decay':
Studies of electrostatic safety during solvent extraction of copper: This work was described in a paper at the 'Electrostatics 2003' Conference at Heriot Watt University, Edinburgh 23-27 March, 2003 "Electrostatic safety during the solvent extraction of copper". (This paper is to be published in J. Electrostatics). The studies showed that with the solvent and extractant liquids used there are no risks of electrostatic ignition in normal plant operation. This is despite the extensive use of HDPE pipework. Safety depends upon rapid relaxation of electrostatic charge within the process liquids. Charge decay times were measured to be in the range 0. 025 to 0.030 seconds for both the loaded and unloaded liquids.
JCI 134 Base Unit for JCI 131 Adverse Conditions fieldmeter.
JCI 155 at NASA:
Enhanced performance of JCI 140 Static Monitor instruments:
JCI 155v6 Charge Decay Test Unit: The new instrument is basically similar in operation to earlier JCI 155 instruments but has the special feature of an integral microprocessor. This enables all basic analysis, display and storage of charge decay curves to be carried out by software within the instrument. Observations are stored to a PCMCIA memory card (or CompactFlash memory in a card adaptor) that can be slot ted into the instrument and can be read, processed and displayed off-line in a microcomputer running proprietary Windows software JCI-Graph . A version of JCI-Graph is now available that also provides for direct on-line operation of JCI 155v6 i nstruments with quasi real time display of charge decay observations. The integral software provides full versatility in setting instrument operation and the measurement arrangements (see JCI 155v6 User Manual). Instrument operating parameters have default values and these can be modified using the push buttons to select and edit parameter values ? for example, the corona voltage and duration, the conditions for ending a run by maximum time or by reaching a set voltage level and whether the plate is retracted quickly (20ms), for fast decay time measurements, or slowly, for measurements on light powders with minimum sample disturbance. The corona charge transferred to samples in operation of JCI 155v6 instruments can be directly measured using a JCI 176 Charge Measuring Sample Support. Measurements on powders and liquids can also be made using a JCI 173 Powder Sample Support Plate between the mounting plates of a JCI 176. A recent update to the instrument has been to move the mains power supply unit outside the instru ment and to provide light ventilation through the instrument when operated from the external power unit. This has been done to reduce the slight heating within the instrument so that internal temperature and humidity are a good match the the surrounding ambient conditions. The latest version of JCI-Graph enables JCI 155v6 instruments to be operated with direct serial data linkage to a PC. This provides basic control of instrument operation and enables charge decay graphs and associated test data to be displayed directly in near-real time. This is very useful when measurements are being made in situations where it may not be easy to read the instrument display or control instrument operation. Charge decay graphs and details of test results and conditions can be displayed, manipulated and transferred into other Windows applications - such as Word documents. (The User Manual for JCI-Graph is available on this Website.
Recent publications: A number of articles have been written on work to measure the surface voltages that can arise on inhabited cleanroom garments when rubbed, and how well this electrostatic performance of garments may be predicted from charge decay and capacitance loading measurements on sample areas of garments or garment fabric. A paper was presented at the EOS/ESD 25th ANNUAL SYMPOSIUM in Las Vegas 21-25 September, 2003: "Test procedures for predicting surface voltages on inhabited garments" by Paul Holdstock (BTTG), John Chubb (JCI), Michael J D Dyer (Barnet). A paper "Predicting the maximum surface voltages expected on inhabited cleanroom garments in practical use" with Paul Holdstock (BTTG) and Mick Dyer (William Barnet and Son Inc) was presented at the ESTECH 20 03, Contamination Control Division meeting in Phoenix, Arizona.18-21 May, 2003. A paper "Predicting the maximum voltages expected on inhabited cleanroom garments in practical use" with Paul. Holdstoc k (BTTG) and Mick Dyer (William Barnet and Son Inc) was presented at the Institute of Physics 'Electrostatics 2003' at Heriot Watt University, Edinburgh, 23-27 March, 2003. "Assessing the influence of electrostatic charge retained on materials" 'Compliance Engineering' 2002 Reference Guide p124 'Can cleanroom garments create electrostatic risks?' was published in 'Cleanroom Technology' March, 2002 and is available in the on-line ESD Journal. A second article "Can one predict the surface voltages that will arise on cleanroom garment by tribocharging?" shows that prediction is indeed feasible. This article is available on this Website and in the on-line ESD Journal. A Test Method we have developed for measuring the surface voltages that arise by tribocharging on inhabited cleanroom garments is available. The procedure we have developed for predicting the maximum surface voltages to be expected on inhabited garments isavailable as a PowerPoint presentation and as a document . This work was presented at the ESTECH Conference in Phoenix, Arizona in May.
"COMPANY PROFILE" A profile of John Chubb Instrumentation has been presented in the on-line 'ESD Journal'. ELECTROSTATIC MEASUREMENTS The Institute of Physics, Static Electrification Group arranged a meeting on 'Electrostatic Measurements' on 13 November, 2001 at the Institute of Energy, Devonshire Street, London. The programme for this meeting was arranged by Dr Paul Holdstock, British Textile Technology Group (email: pholdstock@bttg.co.uk). A paper on "Measuring the electrostatic suitability of materials" was presented by John Chubb. An article "Cleanrooms and static" has been published in 'Cleanroom Technology' (Polygon Media Ltd), October 2001 p30IEEE-IAS 1999 meeting Phoenix, Arizona: The paper presented by John Chubb at this meeting, 3-5 October, 1999: "Measurement of tribo and corona charg ing features of materials for assessment of risks from static electricity" has now been formally published in IEEE Transactions on Industry Applications 36 No 6, Nov/Dec 2000 p1515-1522. The paper as presented at the meeting and the overhead slides are available on this Website. '2000 IEEE, Rome': A paper "Measuring the shielding performance of materials" was presented at the '2000 IEEE-IAS' meeting in Rome, 8-12 October. (Click here for overhead slides presented). An article based on this paper "How effectively do materials shield against transient electric fields?" is published in IEEE Ind Appl Magazine 8 (5) Sept/Oct 2002 p13. This paper is to be published formally in IEEE Trans Ind Appl later this year. 'ESA 2000', Niagara Falls: Two papers were presented at the Electrostatics Society of America 'ESA 2000' meeting, Niagara Falls, June 18-21 , 2000: "New approaches for electrostatic testing of materials" and "A system for the advance warning of lightning" The paper on testing materials was published in 'Journal of Electrostatics' 54 March 2002 p233. 'Packaging Technology' & 'Bulk Handling': An article "Resisting the charge" has been published in 'Packaging Technology' May/June 2000, p13 and an article "FIBC ignition risks from static electricity" in 'Bulk Handling International', May/June 2000, p25 Lectures in Helsinki: John Chubb gave two lectures in Helsinki 4 May, 2000 as part of the STAHA programme of VTT Automation. Notes prepared for these lectures 'Electrostatic measurements: Opportunities and problems' and 'Electrostatic measurements: Applications' can be found on the VTT Automation Website as well as the JCI Website (access via Sitemap). ESD Symposium: John Chubb attended the 1999 Symposium in Orlando, Florida at the end of September as co-author, with Paul Holdstock (BTTG), of the paper presented by Ray Gompf (NASA) "Electrostatic test methods compared".Charge decay studies: Studies with the JCI 155 have shown that the decay of corona charge correlates well with the decay of triboelectrically generated charge. This supports the JCI 155 approach for assessing the ability of materials to dissipate static electricity. Studies have also shown lack of damage by the use of corona - and lack of any relation of decay time to resistivity. The JCI 155 approach is now used quite widely in industry, especially in relation to fabrics (for instance by Marks and Spencer for assessing fabrics for low cling lingerie) and by a number of pharmaceutical companies. Some comments on the validity of corona charge decay measurements are included on this Website. Also included are some comments on methods of charge decay measurement in use. The corona charge decay method for assessing materials is described in a new draft IEC Technical Report: IEC 61340-5-1: 1998 "Electrostatics - Part 5-1: Protection of electronic devices from electrostatic phenomena - General requirements". (JCI versions of the ways to measure charge decay and capacitance loading of static charge retained on surfaces are included on this Website). 'Threshold': Letter to the Editor EOS/ESD Association Newsletter 'Threshold' July/August 2001 in response article by Niels Jonassen in May/June 2001 issue of 'Threshold' "Comment: Voltage on insulators IS meaningful!" . Another letter to 'Threshold' was published in the January/February 2000 issue (p6): "Chargeability and influence of surface charge";
JCI instruments and facilities: JCI 140 Static Monitor: Experience with PC based digital data recording shows great advantages for viewing and storing electrostatic observations with JCI 140 Static Monitor instruments. Observations can be made to the full fast response capability of JCI 140F instruments and the data logging capability provides opportunity for detailed monitoring of long term observations. Picotechnology, for example, provide compact and low cost units with both digital storage oscilloscope and datalogging facilities via a PC. The software is Windows compatible. (With these ne w opportunities for direct display and recording od observations the C option for JCI 140 instruments has been discontinued). For long term continuous observations, JCI 140 and JCI 140F instruments may be powered from an isolated 12V regulated d.c. supply via a 2.1mm d.c. connector in the instrument back cover. (Suitable 12V 'wall cube' units are available from JCI as the JCI 142). The following attachments are available for JCI 140 instruments: JCI 145 Air Ionisation Test Unit : for measuring the ability of air ionisation to dissipate static JCI 147 Faraday Pail: for measuring charge on items, powders and liquids with resolution to 1pC JCI 148 Electrostatic Voltmeter: for measuring discrete voltages (for example on people) with negligible current drain up to 20kV. The input impedance is around 1015ohms to over 15kV and the self capacitance is about 7pF. A new JCI 504 Lightning Warning System has been developed from the original JCI 501 system. This provides the same capabilities as the original JCI 501 system but with th advantage of enhancements to the Sensor Unit and incorporation of the microcomputer into the Base Unit for analysis and display of observations.
Charge and discharge measurenents:
A hemispherically ended discharge probe, JCI 179, can be mounted d irectly on the BNC input connector of the JCI 178. This enables measurements to b e made with a shielded probe of the quantities of charge transferred in low energy electrostatic spark discharges. Sample Supports for JCI 155 Charge Decay instrume nts: Powder and liquid samples can be mounted in a JCI 173 Powder Sample Support Plate between the mounting plates of a JCI 176. This enables measurements to be made of the quantities of charge transferred and estimates of capacitance loading for these materials. A simple Support Plate, JCI 172, is now available to help measurements on light powders with the JCI 155 and the JCI 170 Powder Sample Support. The unit provides a simple stand-off of the powder surface from the JCI 155 test aperture to avoid risk of ingesting powder into the JCI 155 mechanics at movement of the air dam.
JCI 131 Adverse Conditions Fieldmeter: Sales:
Monroe Electronics instruments:
Consultancy: Meetings:
STATIC AND PACKAGING: A meeting of the Printing, Packaging and Papermaking Group of the Institute of Physics in London, in conjunction with the Electrostatics Group, discussed the relevance of static electricity to packaging. The programme and abstracts for this meeting are available on this Website. The overhead slides for the Introductory Comments and about the assessment of materials by John Chubb are also available. Electrostatics Conference: The 'ELECTROSTATICS 2003' This Institute of Physics International Conference was held March 23 to 27, 2003 at Heriot Watt University in Edinburgh as part of the 'Physics Congress'. The Conference was preceded on the Sunday (23 March) by a 1 day 'Introductory Workshop'. A general overview on static electricity and relevant methods for its measurement is available on this Website as: "An Introduction to Electrostatic Measurements". This is an enhancement of the Notes prepared for the: 'Introductory Workshop in Electrostatics' that preceded the 'Electrostatics 2003' Conference held at Heriot Watt University, Edinburgh. Useful Websites:
Published papers: Papers included on the JCI Website include the two papers presented at the ?Static and Textiles? meeting in Brighton on March 18,1998 "Studies of charge transfer, peak voltage and charge decay on a variety of materials" and "The control of body voltage getting out of a car". There is also the pa per as presented at the IEEE-IAS meeting in Phoe nix, Arizona October, 1999: "Measurement of tribo and corona charging features of materials for assessment of risks from static electricity". The overhead slides presented are also available on this Website. A paper has been published in the on-line ESD Journal Website "The control of risks from static electricity" |
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