Mechanical Seals and Magnetic Couplings in Conformity with Atex 95
Burgmann Dichtungswerke GmbH & Co. KG, Wolfratshausen / Germany, offers a temperature monitoring unit for the operation of mechanical seals and magnetic couplings in conformity with Atex 95 (Directive 94/9/EG).
Both the seals and the monitoring units are certified as complying with Atex.
Temperatures have to be monitored as soon as the users of pumps and/or agitators are unable to guarantee that the respective mechanical seals or magnetic couplings are sufficiently lubricated at all times or that their seal faces or sliding bearings are being supplied with enough fluid, e.g. for cooling. The system presented by Burgmann consists of a sensor and a temperature monitor.
In mechanical seal applications the sensor is embedded a short distance from the sliding face in the stationary ring (seal face or seat). Reliable and exact measurement of the sliding face temperature is thus possible. The sensor signal is sent to the temperature monitor. If the temperature rises above a pre-selected threshold, the output voltage of the temperature monitor will change. Connecting this change of voltage to the safety relay of the pump will make sure that the pump is switched off in time to prevent the seal from overheating.
In pump applications with magnetic couplings, insufficient circulation of the medium can result in overheating of the sliding bearings and prevents dissipation of the eddy current heat which arises in the can. In this case the temperature at the can has to be monitored by a suitable electronic temperature sensor.
Each Burgmann mechanical seal or magnetic coupling can be issued with a declaration of Atex 95 conformity, provided the technical design and arrangement comply with the required operating conditions and the following working conditions are known exactly:
• Area of use (zone, device group)
• Medium (medium class)
• Maximum pressure at the mechanical seal or magnetic coupling
• Maximum temperature of the medium at the mechanical seal or magnetic coupling
• Type of seal, combination of face materials and size or MAK type and materials
• Required temperature class