Starting and Stopping Gear, Danbury Plant.
3249 Sprague Hill Road, Falconer, New York 14733
These are copies from an old magazine, 'Power,' that I'm sure has been long out of print. Their subscription rate of $1.00 per year does tell us something about inflation, doesn't it?
The engines shown are quite unique in that they are two cylinder 'Otto' engines, with the cylinders in a piggy-back configuration. As stated in the text, both connecting rods were connected to the same crank throw, with the crank shaft midway between the two cylinders. These engines were rated at 90 HP.
As the attached copy is from the 'Power' magazine dated August 1894, it's apparent that these engines were built prior to that date. Interestingly, these engines do not even appear in the 'Yellow Book.'
Instances have multiplied of gas engines in sizes which entitle them to consideration as prime movers in work of some magnitude which have run at an expense for fuel much less than that required by the best steam engines of the same capacity. Most of the reports of such tests have come from abroad, but some two years since the Danbury and Bethel (Connecticut) Gas and Electric Light Company, in considering how best to meet the demand for electric lighting, concluded to test the adaptability and efficiency of gas engines, using producer gas for this purpose. For two years, the experiment has been going quietly on, and at length we are able to describe for the readers of Power the apparatus used and the results obtained. A general idea of the plant will be gathered from the engraving and the plan on page. Three engines, each 14? inches in diameter of cylinder by 24 inches stroke, and running at 165 revolutions per minute, are used. They are of the Otto type, furnished by the Otto Gas Engine Works, Philadelphia, and rated at 90 horsepower each. Two horizontal cylinders are used on each engine, placed one above the other, the connecting rods from both taking on to a single crank pin. The center of the main shaft is on a line midway between the cylinder centers. The engines are normally run with producer gas, but the illuminating gas is also piped to the cylinders in such a way that the attendant can, by a simple movement of the cam shaft, set the valve cam to trip either the producer or illuminating gas supply while running and without losing a stroke. The charges are ignited in the cylinder by electric sparks. The six-foot driving wheels of the engine are connected by 16-inch Underwood cotton belts, faced with leather, to 25-inch pulleys upon a main line of shafting, from which the dynamos are driven.
The method of throwing an engine into or out of connection with the line is ingenious and effective, and will be apparent from the photographic reproduction and drawings. Each belt is supplied with a tightener, carried in bearings on a crosshead moved in a vertical frame by means of a leading screw operated by a crank through bevel gearing as shown. The same crank which raises and lowers the tightener turns two horizontal shafts with worms working into worm gears on both sides of the driven pulley. Extending between these gears on one side are four rollers, as shown, upon which the belt is supported when the worm gears are turned in such a position as to bring the rollers between the pulley and the belt. When the rollers are turned toward the engine side of the driven shaft the belt rests on the pulley and the tightener is run down to take up the slack. By means of a simple nut in the cross-head of the tightener the latter may be thrown into or out of motion when the crank is being turned, so that the belt supporting rollers may be adjusted independently of the tightening pulley. On starting an engine up in this way the pulley upon the shaft is temporarily the driving pulley, it being necessary to turn the gas engine over a few times before it will run of itself. The switching in is therefore done with the engine idle and the shaft in motion. For turning the shaft before the first gas engine is started a small Westinghouse steam engine is provided, as shown in the engraving. The shaft carries also a heavy flywheel, to preserve a uniformity of rotation despite the intermittent character of the moving force, and there is no noticeable fluctuation of speed even when only one engine is in use. When two or three engines are run the distribution of effort can of course be made more even. As the engines are set side by side, with their crank shafts in line, the latter are connected up by flexible couplings when running, with the cranks 180 or 120 degrees apart, according to whether two or three engines are in operation, the governors being connected so that the plant acts as one four or six cylinder engine. This distributes the strain of each impulse among the two or three units in operation.
The transmission machinery was put in by the Geo. V. Cresson Company of Philadelphia, the engineer of the work as a whole being A. W. Burchard, M. E., of Danbury. The cylinders are kept cool by circulating water from the gas holder through the jackets. A considerable body of water is used in the holder, and being circulated through the cylinder jackets and back to the holder does not become unduly heated during the continuance of the run. The steam boiler used in making the producer gas and for heating, supplies steam for the fifteen horsepower starting engine. No attempt is made to recover any heat from the exhaust, which passes through 'exhaust pots' which are simple enlargements of the exhaust pipes, to deaden the noise, and makes its final exit through a small brick stack.
The electrical equipment consists of one 1500 and one 1750 light Westinghouse alternating dynamo, with separate exciters, three 45-light Schuyler arc machines, and two 40-light Schuyler commercial machines. When it is desired to stop a dynamo its belt is shifted to a loose pulley carried on an extension of a journal box independent of the shaft, an arrangement of great simplicity.
The building was constructed with the intention of making it virtually fireproof. The walls are of brick, the floors of cement, the trusses of iron, planked and covered with slate. The dynamos rest on a brick and iron foundation, the wires being carried in a conduit underneath the floor to the switch boards, thus avoiding any exposed wires in the station.
So successful and satisfactory has been the operation of the plant that the company have given up the use of their former steam plant, depending altogether upon this station.