JXL/GGR Selection Guide Equipment for Hazardous Areas Selection Notes for JXL Couplings & Cast Iron Bellhousings This is intended as a guide for the selection of bellhousings and couplings for the use in hazardous areas. Consider motor power and speed against coupling nominal torque. If the resilient bushes fail, metal-to-metal contact could occur, in order to minimise the risk of this situation, we recommend that the end user carry out periodic inspection of the coupling assembly with particular attention being applied to the resilient bushes. This can be further enhanced by the application of a large service factor to the coupling at the selection stage. By the nature of the design of JXL couplings, a large service factor is easy to achieve, as a general rule, a full compliment of resilient bushes with each coupling selection will naturally give a high service factor. Consider the site of the housing and coupling assembly. If the assembly is to be positioned in an inaccessible area where periodic inspection will be difficult to achieve or may be ‘overlooked’ a high service factor will be very desirable, in many cases the provision of a dia 50mm inspection hole in the bellhousing will save time when inspecting the coupling. Consider coupling clearance. When selecting JXL couplings for use inside bellhousings, consideration must be given to clearances between rotating and non-rotating parts, based on BSI 9-2000 EN50019: 2000-173, we recommend that this clearance be a minimum of 5.0 mm in all cases, however the standard this information is derived from advises that clearance shall be 1/100 of the maximum diameter (rotating component), but in no case shall the clearance be less than 1.0mm, reference to this could be used in special circumstances, however it is envisaged that 5.0mm should be possible in all cases. Consider vertical mounting. JXL coupling hubs are machined with an additional grub screw at 90 degrees to the grub screw over the key slot, this is to provide additional security against the hubs creeping down one or other shaft when mounted vertically, we strongly recommend the use of this additional grub screw in vertical installations, however, if the additional grub screw is not to be used, it must be removed from the coupling hub and an alternate method sought, eg pinning of shaft keys, spacers or clamp design hubs. Consider mining applications. In mining applications, it is not permitted to allow dust to enter equipment supplied, therefore any inspection holes in bellhousings must be fitted with solid covers. Consider pump removal. GGR bellhousings will be fitted with a centring to enable the pump to be removed without removal of the coupling hub from the pump shaft as standard, where the centring will not interfere with the pump fixing holes. In instances where the diameter of the centring would interfere with the pump fixing holes, provision of a removable pump face on the bellhousing may be required in order to assist with pump removal. This should be requested at time of quotation. 3 #DriveLineHarmony www.jbj.co.uk/couplings.html
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