Product category:
Level Sensors and Leak Detectors
News Release from: Rechner UK | Subject: ATEX certified capacitive sensors
Edited by the Engineeringtalk Editorial
Team on 25 February 2004
Capacitive sensors safe for dusty
environments
Rechner Sensors has a range of new capacitive sensors that are compliant with the new ATEX regulations category 1D and 2D for installation in Zones 20, 21 and 22.
Industry is generally aware that the new ATEX regulations came into force in July last year However, the application of these regulations in the area classified as "dust ignition", ie Zones 20, 21 and 22, has caused some confusion in industry as combustible dust is classified as anything from sawdust through flour to coffee powder
This article was originally published on Engineeringtalk on 31 Jan 2003 at 8.00am (UK)
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Level probes avoid common capacitive problems
Rechner level probes are unique in the way that they work and are now available with evaluation units integral in the head of the level probe.
Proximity sensors come with ATEX certification
Rechner's range of capacitive proximity sensors already includes devices certified StEx "for use in explosion danger areas with combustible dust", and these are now available with ATEX certification.
An additional challenge for engineers has been that many products, particularly in the sensing field, do not meet these new regulations.
Rechner Sensors has now launched a range of new capacitive sensors that are compliant with the new ATEX regulations category 1D and 2D for installation in Zones 20, 21 and 22.
If a suitable Rechner ATEX certified Namur sensor is specified the whole sensor can be placed within an area classified as Zone 20 assuming an intrinsically safe amplifier is used.
Further reading
Capacitive sensors have measure of accuracy
Sensing distance indication (Si) is a new option available with the capacitive high performance sensors from Rechner.
Capacitive sensors claim top performance
Rechner reckons its High Performance sensors are very different from any other capacitive sensor on the market.
However, the most common application is where a sensor mounted through the wall of a vessel to monitor level.
In this case the inside of the vessel is defined as Zone 20 but the exterior falls within Zone 21.
Standard PNP or NPN sensors can be used in this type of Zone 20 application - providing only the active surface (sensing head) is within the vessel and the body of the sensor is exterior to the vessel within Zones 21 or 22.
This configuration fulfils the requirements for category 1D installation.
These three- or four-wire proximity sensors have a supply voltage range of 10 to 30V DC with PNP or NPN output, and are ideally suited communicate with all common PLCs.
Sensors for category 1D and 2D are available in M30, M32 and 1in housings.
Namur capacitive versions category 2G (for use in gas Zone 1) are also available from M8 upward.
The above versions are available with different housing materials and combinations.
The selection of the correct housing material is dependent on the media to be detected.
The versions with stainless-steel housing and with PTFE sensing head have become established as standard within the field of bulk materials.
In addition to capacitive sensors meeting Category 1D, 2D and 2G Rechner also has a range of Namur inductive sensors, with housings down to 4mm diameter for category 2G and from M12 and above these are actually dual certified 2G and 1D.
Rechner has produced a poster that explains fully the ATEX Directive.
A new capacitive catalogue is also available that along with many new products across the board, contains the information relating to all the ATEX certified capacitive sensors.
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