Years ago, I used to work at a transmission shop, pulling, rebuilding, and reinstalling transmissions and transaxles. Along with the transmission work came other drivetrain related needs like rebuilding differentials.
I recently visited with our Thai distributor, and while in Thailand we investigated a blow off need for a customer at an axle factory. The specific need was to improve blow off of a banjo axle (A banjo axle is (typically) a rear axle used commonly in trucks or heavier-duty vehicles. The significance of a banjo axle is that the differential unit can be completely unbolted and serviced, apart from the actual axle housing. Other styles house the differential unit within the pumpkin in a little bit of a different manner. Banjo axles allow for easy service and quick replacement if needed (a big plus for trucks putting heavy strain on the differentials) after welding and intermediary finishing operations.
The blow off needs were two-fold in this application. First, the axle assembly is sent through a washing process to remove any fines present from deburring, after which the exterior needs to be blown dry. Next, the internal sections of the tube, especially the baffles for oil flow, need to be blown off for the same reasons.
The first step of the process is experiencing efficiency problems, most notably a drop in line pressure for the surrounding applications when the blow off turns on. We counted over 120 nozzles in use when the first stage of the blow off engages, placing a huge demand on the compressed air supply. (This machine was fed with a 2” line from a 6” header.)
Immediately, we wanted to know the demand of air using the existing nozzles, but we also noticed that they were dangerous in their design. If the existing nozzles were to come into contact with a person for any reason, they could be dead-ended, which poses a safety concern. Next, we thought about a way to limit the air demand after efficient and safe nozzles are installed.
We recommended a series of model 1101 EXAIR Super Air Nozzles, with a cascaded blow off from left to right, then right to left, and finally from the center outwards. The process would require installation of some additional air controls and logic, but the compressed air demand from the logic controls alone could reduce demand significantly. Couple this with the efficiency improvements of the EXAIR nozzles, and the the efficiency improvements are compounded.
The second step of the process fed a lance into the axle assembly, blowing debris toward the center. To improve this stage of the blow off, we advised to install a 1006SS Back Blow nozzle, “pulling” the fines away from the center area of the axle. The center area of the axle contains baffles used to divert and direct oil flow, and the fines were accumulating in the folds of these baffles. So, rather than blowing the debris into this problematic area, we opted for the Back Blow nozzle to remove the debris and keep it away from the critical folds of the baffles.
It was good to see the solutions an EXAIR product can offer for this application in person, even if it was halfway around the world. If you have something similar or would like to discuss your particular application, contact an EXAIR Application Engineer.