Garrett Displacement Lubricator

[andrew hawkswell]

The late built Burrell roller "Hero" also has one. Having had one apart, I know what they look like inside, and can provide a sketch if you need some clues, but as for exact dimensions you will have to measure one. The 1/2" in the spec above will probably refer to the BSP thread size (male parallel) which is where it connects to the steam chest. The top of the body, (which is a casting but machined on the outside), has a "three leaf" interrupted flange facing outward, corresponding interrupted flange on the cap facing towards the centre, so that a part turn engages the flanges and prevents the top coming off. The top of the body is closed off except for the centre filling hole (about 1" diameter) and this hole sits at the centre of a slight depression machined into the top surface of the body. An inverted mushroom shaped piece of gunmetal is connected to that threaded spindle you can see coming through the cap, so that as it is tightened, it pushes down onto the edge of the filling hole in the upper face, sealing it against steam pressure and loading the flanges. The rest of the lubricator is standard practice, a pipe inside coming up close to the top, and regulated at the base by the feed adjustment screw - just a needle valve with a typical stuffing box, and the drain is very similar on the other side - from memory the condensate just trickles out of a weep hole in the drain stuffing box body. The two wheels engage on small squares on their respective shafts and from memory the nuts on the end of the shafts are 3/8 whit, the squares being 3/8 A/F. I think the thread in the top cap is 1/2" whit.