Mike's Workshop Notebook

Worthington Water Pump

The Worthington Water Pump, is a duplex, dual acting water pump. THis pump will grace the running board of a Shay locomotive in the near future. The chance of ever building this pump again are extremely small. The small parts are to tiny for my big fumbling fingers, not to mention the difficulty of securing the inside cylinder covers and adjusting the packing glands. The fabrication was enjoyable, the assembly, not much. Another issue is the fact that the steam and water cyliners are separate assemblies, held in alignment by bolts through the base. It can be difficult to align and secure them. If I ever make another of these pumps, I would cast the cylinders and base as a single unit, thereby eliminating this hassle.

Photos

Worthington Pump
Modeled in CAD (Fusion 360) and 3D printed each part of the pump. This validates the drawings, gives insight into how best to machine and workhold the parts.
Worthington Pump
The 3D printed parts assembled, gives a first look at the scale and look of the pump.
Worthington Pump
Machining the water piston. A custom HSS lathe tool was ground for cutting the piston grooves to size and shape.
Worthington Pump
The water and steam pistons assembled on the piston rod poised on top of steam and water cylinder housings. Two piston-rod-piston assemblies are required.
Worthington Pump
The water piston fits nicely in it's cylinder bore.
Worthington Pump
These 3 components form the water valve assembly. Eight stainless steel ball bearings form the working portion of the inlet and outlet valve pairs.
Worthington Pump
The components ready for assembly.
Worthington Pump
The pump roughly assembled on the base. The significant flaw of this design, IMHO, is that the water and steam assemblies are seperate assemblies. But note that the water and steam pistons are at opposite ends of the same piston rod! This makes alignment of the assemblies critical.
Worthington Pump
The author's proposed solution to the cylinder alignment problem is to machine a rod, that would align and set the separation of the cylinder assemblies.
Worthington Pump
The alignment rod is inserted water (small) end first, through the steam cylinder then into the water cylinder. The whole thing is then screwed down to the base. I did not like the sole use of screws and will try the addition of a layer of Loctite to hold things in place.