Hydraulic power pack for a Zone 1 hazardous area
Extronics received an enquiry to provide a solution for a Zone 1 hydraulic power pack for a lift. This application had previously been provided by Extronics using flameproof enclosures and intrinsically safe devices, however in this instance the size of the flameproof motors required prevented the solution being feasible.
Extronics worked with Helipebs Controls Ltd to design an enclosure which would be suitable to withstand a very high flow of air. The high flow of air was required to purge the large enclosure 1750 x1750 x1060. The finished enclosure was fabricated by the Helipebs Controls Ltd.
Helipebs also required a HMI display to control the operation of the hydraulic power pack, it was decided that an intrinsically safe device would be best suited to this application. Because intrinsically safe devices do not pass the impact tests required for purged enclosures, the HMI was installed inside a separate enclosure within the main enclosure, giving the impression the HMI was installed into the main enclosure.
The enclosure also housed a number of user controls in the form of push buttons and lamps. This solution utilised the iPURGE200 purge controller, which was housed internally. Due to the large volume of the enclosure an additional outlet kit was used to increase the flow of air out of the enclosure, this helps reduce the internal pressure.
Extronics provided the certification for this solution, travelling to site with the notified body and performing the necessary tests. The completed solution required only 20 minutes purge time.
