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NORMAN XV. VHEELERy OF NEW' YORK, N. Y.

ARRANGEMENT OF PASSAGES AND VALVES FOR CUSHIONING THE PISTON OF STEAM- ENGINES.

Specification of Letters Patent No. 19,220, dated January 26, 1858-.

To all whom t may concern Be itknown that I, NORMAN IV. IVHEELER, of the city and State of New York, have invented a new and useful Arrangement of Passages and Valves for Oushioning the Pistons, and Partially Balancing the Valves of Steam-Engines; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings and to the letters of reference marked thereon.

The nature of my invention consists in arranging check-valves in passages, which open into the steam cylinder within the piston stroke, so that live steam from behind the piston. near the end of a stroke passes into the clearance before the piston, and into the side pipe and spaces connected therewith, thus arresting the motion of the piston, partiallv balancing the main valves, and filling the dead-space of the engine with steam which would otherwise escape from the engine and be lost.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

In the accompanying drawings, Figure 1 is a sectional view of an ordinary slidevalve engine, with the cushioning apparatus attached, and 2 and 3 are sectional and end views of an engine known as lVheelers pumping engine with the cushioning apparatus attached.

In Fig. l A, is the steam cylinder, B the working piston, C the piston rod, E the slide valve, and D D the steam channels or side pipes; F and G are check-valves placed in the ports which connect the steam cylinder with the channels D D, in such manner that after the slide-valve has closed the exhaust port and just before the piston has completed its stroke it will pass over and beyond F or G and allow steam to pass from behind it,-raising F or G, as the case may be,-into D and thence into the clearance, thus making the pressure upon one side of the piston equal to that 0n the other', when the check-valve F or G closes, and there is an upward balancing presure under the slide valve,-measured by the area of D D. Now if the piston continues its forward motion the spacebefore it will be diminished and the pressure increased therein, and when the stroke is completed, and the steam which caused it exhausted, that which passed through F or G into D, will be retained, and usefully assist in performing the following or return stroke, and so on. In constructing such engines I prefer to give less steam and exhaust lead to the main valve than is usual in ordinary practice.

In Fig. Q it will be seen that the construction and operation of the cushioning apparatus is similar, and that the piston B is represented as having just passed K, which should be shown as opened,) in which case it is obvious that steam would pass up vthrough K into D and D, and into the clearance before the piston, B, thus performing its specific function of cushioning B and partially balancing E-(which should be shown as closed and E open)- besides an incidental function of closing F and opening F, thus allowing the steam contained in A to escape through I, F and H while by the closing of K the steam in the dead-space will be retained and assist in the return stroke.

I claim- Arranging check-valves in the steam passages for cushioning the piston and balancing the steam valves with steam taken from behind the piston substantially as set forth.

NORMAN IV. IVHEELER.

lVitnesses:

JAMES HALL, GEO W. BREGER,