![]() This particular flex coupler is called the Guardian 20 and I used PUR80 urethane poured onto the 2 zinc halves in a mold. Once all together see if the shaft turns freely with nothing binding, there's a slight metal rubbing noise, but thats from the vanes sliding on the housing walls. Plate 1 can be lined up with the corner bolts when re assembling the cartridge, give the unit a little shake when centering the shaft so that all corner bolts wiggle into a centered position other wise there's a chance of pulling the cartridge over to one side when tightening the bolts down. I solved the issue by flipping plate 5 over and using that as the new sealing surface, naturally after more lapping on the wet & dry paper.įor aligning plates 2,3,4,5 you'll need a 3mm rod to slide into the gas bypass hole until it seats into a dimple in plate 4.Ī 7.7mm bolt worked for one corner mounting hole, hold the assembly shaft up and tighten the 2 align lock bolts. It turns out that the end plate (No 5) had a warped surface with a high center and my lapping was only rounding it over more. This gave me a limit as to how far down I could lap the damaged surfaces on wet and dry paper.Īfter lapping and re assembly I found that the shaft spun freely but wouldn't when the plate bolts were tightened. I pulled the plates apart and measured all the tolerances, it seemed that the 0.2mm gap between the round disks(vane impeller) meant that there was a running clearance of 0.1mm. This is officially Part # D10087 DV-85 and is obsolete, meaning you can no longer replace it and rebuild is the only option. My smallest rod was 1mm drill bit which didnt fit anywhere around the shaft and seal hole.įinally, I removed all the fittings, cleaned the filter of hair and debris and blew out all the passages using a compressor. I hang the body upside down so that the shaft is facing up and then lightly tap the cartridge around with a small hammer to get the shaft centered while eyeballing the shaft from above. Its important to center the impeller shaft with the housing body when you remount the valve cartridge, before you tighten the cartridge bolts. I've labelled the bolts in the 2nd photo of step 2. If you're just changing seals and orings then leave the 2 center bolts in and just remove the 4 corner bolts, that way you don't disturb the alignment. Next all the bolts of the square valve cartridge can be removed if you're going to rebuild the unit. Then remove the coupler from the pump shaft, you can leave the one on the motor shaft on. Judging from the blued SS valve in step 2, the unit reached a temp of approx 300☌ in a device that runs normally at 70☌.įirst drain the oil, then remove the front cover housing with the oil sight glass. To compound the neglect, the oil level was at the bottom of the sight glass, no longer cooling or sealing the valve cartridge. The reason for the seize was due to it being run on an ammonia system, there's a warning on the manufacturers website regarding ammonia and sodium bromide(salt), not only do they rinse the oil off the impeller walls, they also contaminate the oil causing it to go green and lumpy. I cover the process to make a new flexible coupler, called a Guardian 20, in step 3. The previous owner had seized the pump and it had destroyed the flexible coupling and caused considerable damage between the vane impeller and front cartridge cover plate. I'm doing a complete tear down of the pump body, including the valve cartridge and I'll show you how to re align the 5 steel plates that make up the unit in step 2. This deep vacuum pump was made in 1988 and most of the parts are obsolete.
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