Show sullivan automatic slide valve V alve hoisting engines V ritten for the mining review steam economy in hoisting engines for mines of shallow to medium depths has been hitherto either a negative quantity or if secured the first cost of the plant has appeared to the average mining company to be out of proportion to the benefits gained there are very many shafts whose depth and production do not warrant the expense of a first motion corliss hoist with automatic steam control for these the only reasonable alternative has been a geared or second motion plant with plain slide valve engines some corliss geared plants have been installed when strict economy of fuel has been necessary but the speed limits practical for corliss valve gear require the stroke when starting the load to set the valves at the proper point of cutoff cut off when the load is under full motion and to lengthen the cutoff cut off again at the end of the trip this is obviously impossible nor would it be possible for the engineer to set the cutoff at its most economical point each time owing to variations in steam pressure and load in these new sullivan hoists this work is done automatically securing economy equivalent to that obtainable in corliss engines but in such a way as in no wise to limit the engine speed it is thus possible to adapt the size and speed of these engines exactly to the work 2 through the valve mechanism marked no 3 the movement of the piston is transmitted through a shaft to the vertical rack no 4 which operates the pinion no 5 located at the outer end of the valve stem for the cutoff cut off valve when the steam enters cylinder no 2 by the movement of the throttle lever the action of the rack and pinion automatically places the steam valves in the position of shortest cutoff cut off at the end of the trip the reversal of the lever to close the main throttles admits steam to the opposite side of the piston in cylinder no 2 and the cutoff is restored to its first position to start the load from the bottom sullivan automatic slide valve hoist details of engines and valve gear use of engines slower larger and therefore more expensive than slide valve engines of the same capacity the sullivan automatic slide valve geared hoisting engines have solved this problem by combining high steam economy with moderate cost As implied an automatic cutoff cut off mechanism has been adapted to the slide valve gear of these hoists this is an engineering achievement never before attained upon a practical working basis it should here be noted that in hoisting engines hand adjustment of the point of cutoff cut off is out of the question it would require an engineers constant attention to give his engines steam for the entire to be performed at the most economical cost ratio A double valve is used as in the case of engines in which the steam distribution is controlled by hand adjustment when starting the load steam is admitted to the cylinders for the entire stroke when the acceleration period is completed the dutoff cutoff dut cut off is automatically set at its shortest position in the following manner when the throttle valve hand lever no 1 is thrown the main throttles are opened by the first two or three inches of the movement admitting steam for the entire stroke to start the load As the lever is pulled back it permits steam to enter cylinder no it will be noted that the automatic cutoff is restored to its first position to start the load from from the bottom I 1 will be noted that the automatic cutoff cut off engine shown in the photographs is in a horizontal position this enables the cutoff of the two hoisting cylinders to be operated by one auxiliary steam cylinder provided for the purpose of giving the motion to the automatic cutoff cut off it will be seen from the above description that the apparatus employed is very simple and its action positive reliable and not subject to derangement it is anti entirely rely automatic requiring no effort of action or attention on the pa part rt of the engineer after the eccentrics have been set to secure the most economical operation possible wit with lithe the service factors of 0 load and steam pressure which are prevalent the slide valves are operated by separate eccentrics with the usual link motion the third eccentric shown being for the cutoff cut off the range of the cutoff cut off is from three quarters to one of cast steel with cut teeth of the short type thus rendering the action of the hoist smooth and quiet two throttles are furnished one on each cylinder when the balanced throttle valves are bolted to the cylinder much more rigid support is provided than if one throttle be placed in the tee with a main coming from 7 7 W 7 ina F Suli sullivan ivan automatic slide valve hoist rear view showing handling motion quarter at the latest setting and from four ten tenths to one tenth at the earliest the photographs here reproduced show the general appearance of these hoisting engines which embody the most modern practice in all particulars the drum is keyed to the shaft the engines being re the boiler and a branch running off to each cylinder the distorting effect on the valve seats in the throttles due to expansion and contraction of the steam pipes is thereby avoided the engines are mounted on heavy duty frames the pillow block section and guide 4 sullivan automatic slide valve hoist side view ver sible A heavy steam operated band brake is furnished this same brake can be operated with a hand operated mechanism consisting of a hand wheel and screw for setting the brake at any point for inspection spec tion packing valves or repairs when the plant is not under steam the gear is made of semi steel and the pinion is made section being cast in one piece the bottoms of these frames form enclosed boxes to prevent oil from touching and being absorbed by the foundations sullivan automatic slide valve hoists are made in several stock sizes and ana all parts part sare are interchangeable this enables them to be built and sold at smaller cost than is possible when each plant is a special propositions hoists for pounds pressure are not kept in stock and the purchase of engines with cylinders suitable for pounds pressure is recommended it frequently happens that these hoists are transferred from one mine to another at which different steam pressures are encountered and the cylinders designed for low pressure would not be suitable for high pressure work the equipment included in the price of these machines includes two throttle valves steam exhaust flanges a steam operated band brake a steam operated link reverse hoist indicators oil cups wrenches foundation bolts and washers further information and prices for individual requirements will be furnished upon application to the company |