Elwell and Parker’s Patent Engine

In our recent notice of the Royal Agricultural Society's Show at Shrewsbury we referred to an exhibit by the Coalbrookdale Company of a high-speed engine, of which it is the sole makers, invented by Messrs. Elwell and Parker of Wolverhampton, and named the Electric, and we are now enabled to lay further particulars and illustrations before our readers. The engine, although of the ordinary single-acting type, presents some features of novelty, and its performances are such as to justify us in saying that for simplicity of mechanism, good arrangement of details, substantial design and high class workmanship, it approaches very near to the ideal of a high-speed machine.

The particular engine which is the subject of our illustrations has a 10 inch cylinder, 9 inch stroke, and is arranged to run at 500 revolutions per minute. This is by no means the highest speed at which it will run, but the company, wisely, does not recommend excessive velocities, as the difference in the power given on the brake and that shown on the diagram becomes so great, owing to the rapid increase of friction, as to seriously detract from the efficiency and economy of the engine.

It will be seen on reference to the illustration that the engine differs from many of the same class by the fact of its having only one cylinder, an arrangement which, it is claimed, without sacrificing steady running, very greatly lessens the number of working parts, reducing the wear and tear to a minimum, and simplifying the whole machine. The cylinder is mounted on a base of box form, which encloses the working parts, and into which the exhaust steam passes. It is provided with circular facings on each side for the two side covers forming the main bearings, a square cover for access to the interior, and the exhaust outlet. The position of the latter plays an important part in the working of the engine, as upon this the efficient lubrication depends.

The exhaust steam condenses slightly as it passes through the base, and the water with the oil floating on the top of it accumulates and rises up to the level of the outlet. Before, however, it quite reaches this height, the connecting-rod end is arranged to dip into it at each stroke, which splashes the oil and water over the whole of the moving parts. The main bearings are of very ample length, and fitted with phosphor bronze bushes.

A passage is cast in the cover above the bush which catches the oil and water and conducts it to the outer end of the bearing, from whence it circulates back along the usual oil grooves into the base again. A small stuffing box and half-round gland serve to prevent any leakage to the outside. The crank shaft is of forged steel, and the balance weights are dovetailed on, and securely bolted.

The slide valve is of the piston type, of novel construction, It consists of three rings, united to each other and to a central boss by webs, the central ring forming a diaphragm to divide the steam and exhaust ports; the other two forming guides, which prevent the cutting of the edges of the ports. A valve of this character is found to work quite tight without any spring rings, and remain so after a large amount of use. The passages are designed to allow a maximum speed of 5,000ft, per minute for the steam, the exhaust being enlarged as much as possible, and an auxiliary port formed at the lower end of the cylinder, to be uncovered by the piston in its travel.

We have now before us diagrams taken from this engine at various speeds showing a very good distribution of steam, which should go far to overcome the objections often raised against this class of engine on the score of economy. The governor is placed horizontally across the cylinder cover, operating an equilibrium valve in the steam pipe, and is made extremely sensitive in its action by a very neat device adjustable to any required speed. The driving shaft is carried by a phosphor bronze bush, bolted to the cover, at the outer end of which is the driving pulley. The lubricator, which supplies oil to the whole of the engine, with the exception of the governor spindle, stands on the steam pipe. Speaking generally of the engine, we may say that the whole of the flanges and phosphor bronze bushes are bright, and fitted with bright nuts; the flywheel is turned and polished, and the cylinder lagged with sheet steel, forming a very handsome and compact piece of workmanship. The castings are of an exceptionally clean and perfect character.

These engines have up to the present been principally supplied to the inventors, Messrs. Elwell and Parker of Wolverhampton, for use in conjunction with their dynamos and accumulators, where they have been a great success. We may mention, in conclusion, that the Coalbrookdale Company is now engaged in re-arranging and adding to its engineering department, in which, when finished, it will be able to deal with work of the heaviest and highest class.