Polymer Development for a Portable Environmental Gas Analyser
Polymer Compounders are based in the North East of England and have earned a reputation as a partner of choice for material development and product solutions within the moulding community. Our technical team ethos is to work in partnership with our customers to help guide them through new product development, thereby ensuring the material selection meets the requirements of their technical specification. It is our knowledge of polymers and our strategy to continually explore product and technical innovations that enable us to ensure our customers benefit from improved technical, aesthetic and productivity performance.
We were approached by Geotech, a Global Leader in gas technology analysis to develop a material for a new environmental gas monitoring device they were designing. The device needed an extremely rugged plastic casing as it would be used out in the field and in addition, the casing also needed low surface resistivity whilst still allowing GPS and Bluetooth signals to penetrate. With over 25 years of experience in compounding engineering thermoplastics, Polymer Compounders were called upon to custom engineer a product that met all the criteria.
What were the key objectives of the technology development programme?
To develop a material with the following properties:
>a low surface and volume resistivity of < 10^9 ohms to meet the latest ATEX certification requirements
>to not act as a Faraday Cage thus allowing radio signals for GPS and Bluetooth to enter and exit the case body
>be able to maintain an IP rating after conducting a drop test in accordance with the ATEX directive from 1m at -20 degrees Celsius.
>to adhere well to a soft touch over-moulding material
>be colour matched to an exact RAL standard.
How were these objectives achieved and what are the key innovations?
To combine all of these requirements into one material was quite unique and seemed an impossible challenge at first. The usual additives to improve the electrical conductivity of a polymer were out of the question as they had a severe detrimental effect to the impact performance, meaning the device would never pass the drop test. Furthermore, the highly conductive materials also produced a shielding effect which prevented the GPS and Bluetooth signals from passing through.
A solution was proposed by one of our raw material suppliers, in the form of a new additive technology utilising multiwall carbon nanotubes. This graphene based material, which is stronger than steel has remarkable electrostatic dissipation (ESD) properties and could be blended with our polymers to give the performance the customer required.
The starting point for the polymer selection was a high impact grade of ABS that had previously been used in industrial safety helmets, which are also tested for low temperature impact performance.
A number of polymer formulations were intensively developed at our test and design laboratory in Durham, and then injection moulding samples were manufactured on our laboratory extruder, each with a different level of the conductive additive. A specialised pigmentation package was also added so that the RAL colour could be achieved. The samples were supplied to the moulder so that Geotech could evaluate the performance of the final application and determine the optimum level of conductive additive to use.
External testing showed that the results far surpassed the level required, with surface resistivity measured at 7.58×10^7 Ohms and a volume resistivity of 5.0 x 10^7 Ohms/cm. The drop impact test and signal transmission tests were also successfully passed.
The product has now been fully commercialised with regular orders on our works schedule. Geotech, to the best of their knowledge, are one of the first to manufacture landfill and biogas portable equipment for use in potentially explosive atmospheres to the latest ATEX standards because of this innovative solution.
What is special about this technology development and what are its implications?
This development has proved that it is possible to achieve good levels of conductivity in conjunction with high impact values for rugged electronic hand held devices with radio signals delivered and received from the outside world in the ever-evolving age of information technology. This could benefit many other manufacturers of devices that require similar performance in the future.
Here is a snippet about the product itself courtesy of https://www.geotechuk.com
The GA5000 is an ATEX certified portable gas analyser for the landfill gas market. Easy to use and calibrate, the GA5000 benefits from our market leading reliability and helping you to standardise monitoring routines, whilst supporting environmental legislation compliance.
About@GeotechUK GA5000 portable landfill gas analyser
Designed and manufactured in the UK, more than 3,000 GA5000 portable gas analysers have been sold in 60 countries worldwide.
Built for the landfill gas market, the GA5000 is safe, reliable and ATEX, IECEx, MCERTS, CSA and UKAS calibration (ISO17025) certified. The GA5000 is used to measure critical gases such as % CH4, CO2 and O2, H2S (up to 10000ppm), NH3, H2 and CO (H2 compensated). It has been specifically designed to provide our customers with the peace of mind that at first stage analysis, they will have accurate readings of +/-0.5% after calibration for CH4 and CO2 (+/- 1% O2)………..
More information about this product can be found over at: https://www.geotechuk.com/products/ga5000/