US283749A

US283749A - Eobeet c

Info

Publication number: US283749A
Authority: US
Publication date: 1883-08-28
Anticipated expiration: 1900-08-28

Description

Patented Au w H a m u m it... H v l: fi ma s mwg I a i Q2 xx 1 m. Washmghm, D. c.

lhvrrnn Srarns Parent @rrrea ROBERT c. BLAOKALL, or ALBANY, NEW roan.

RELIEF-VALVE FOR LOCOMOTEVE-ENGENES.

SPECIFICATION forming part of Letters Patent No. 283,749, dated August 28, 1883,

Application filed July 5, 1882. (No model.)

To all whom it may concern:

Be it known that I, ROBERT C. Bniicnann, of the city and county of Albany, and State of New York, have invented certain new and.

.a locomotive boiler and cylinders, showing one side in section for thepurpose of exhibiting underlying parts that are affected by my invention; Fig. 2, a side elevation of the same, with parts in section for the purpose above described; and Fig. 3, a vertical section of one form of relief-valve I use for effectuating my invention.

The object of my invention is to remedy a defect now existing in locomotive-engines, and which is made manifest when, in attempting to avert an accident, the valve motion of the engine is suddenly reversed while the engine is moving ahead at a rapid rate of speed. XVhenever such a reversal is effected the cylinders of the engine operate as air-compressors to fill either the boiler or steam pipesaccording to the condition of the communicating parts that are open to the said cylinders-with a large volume of air under great pressure; and if such reversal occurs after the throttle-valve has been closed, it is always attendedby the blowing-off of the steam-chests, and thereby the engine is left in an unmanageable condition, and, for the time, is a useless wreck in the presence of a danger that the engineer has been striving to avoid. On the other hand, if the said reversal is effected while the throttle-valve remains open, the air forced into the boiler by the action of the pistons of the steam-cylinders soon produces an excessive accumulation of pressure in the boiler that will strain it to such a degree that it soon becomes absolutely dangerous.

To remedy this defect my invention consists in providing the engine with an automatic relief-valve placed at any point between the throttle-valve and slide-valves, preferably upon the steam-chest, where it will have a free and open communication with the steam-pipes of the engine only. Said' relief-valve, adjusted to open at a slightly higher pressure than the I maximum pressure carried on the boiler, but below the degree of pressure required toproduce a rupture of the parts, will permit the excess of air-pressure to escape from the steampipes, and thereby relieve the structure from the undue strain engendered by the compression of air by the pistons, and, by means of the said relief-valve, a uniform pressure of air, whose maximum point will be within the limit of safety, will be maintained in the steammotion, the steam shut off, and the valve'motion reversed) to serve as an opposing medium to resist the movement of the pistons of the engine, which resistance will quickly overcome the momentum of the moving train and stop its motion; and in this respect the volume of air maintained in a state of compres sion in the steam-pipes and steam-chests will, in conjunction with the pistons of the engine, perform the functions of an atmospheric brake in stopping the motion of thp train.

As illustrated in the drawings, A represents the forward end of the boiler of a locomotiveengine; B, the cylinders of the engine; 0, the steam-chests for containing the slide-valves of the engine; 0, the steam-chest covers; D, the throttle-valve, E, the main steam-pipe; E, the branch steam-pipes for connecting the pipe E with the cylinders 13, and F the steam-passages for conveying steam into the steamchests. All of the aforenamed parts, being the usual and well-known constituent parts of an ordinary locomotive-engine, do not of themselves constitute my invention. It will be seen, and must be clearly understood, that a free and uninterrupted communication is always open between the steamehests C, steam-pipes E and E, and steampassages F; and, it must also be understood, whenever the pistons are reciprocating in the cylinders 13, there is, by the operation of the slide-valves of the engine, an intermittent communication established between the interior of said cylinders and the steam-chests and steam-pipes G is a relief-valve, which I employ for effectuating my invention, and which may be of any suitable style of spring-actuating puppet valve. Said valve may be applied at any accessible part of the engine where a direct cominunication may be obtained for said valve pipes and steam-chests (while the engine is in.

either with the steam-chests or steam-pipes. As indicated by the arrow marked 1, the reliefvalve G is placed over the top of the boiler, and communicates with the main steam-pipe E where the said pipe extends into the smokearch of the boiler.- As indicated by arrow 2, said relief-valve communicates with the steampassage F, and, as indicated by arrow 3, it is inserted in the cover 0 of one of the steamchests.

Storage-tanks may be connected with the escape-pipes of the relief-Valves for receiving the compressed air discharged from said valves, which air may then be utilized when required for. operating air-brakes in the usual manner.

It will be readily understood by those versed in steam-engineering that while a locomotive with a train of .cars is running in either direction at any considerable rate of speed, if the valve motion of the engine is suddenly reversed it will not immediately effect the stoppage of the train, but, on the contrary, the momentum of the train will compel it to continue its course for a time and cause the slide-valves to move in a direction that'is contrary to that required by themovement of the pistons, and, as a result of this action, the pistons will continue to draw air into the cylinders through the exhaust-openings and expel it (the air) from the cylinders through the steam-ports into the steam-chests and steam-pipes, wherein-in the absence of any suitable means of escapeit will become so excessively compressed that the steam-chests will be blown off, and the'locomotive will become an un- 5 manageable wreck. By means of relief-valves G, as herein shown and'described, the accumulated pressure in the steam-chests and steampipes is, at its maximum, kept below the point where it can produce a rupturing strain, and- 40 as an incident due to my inventionthe compressed air confined in the steam chests and pipes will resist, the movements of the pistons and quickly stop the motion of the train.

I am aware that relief-valves have hereto-' fore been used in the cylinder-heads and at intermediate points between the slide-valves and pistons of steam-engines for the purpose of preventing the blowing off of the cylinderheads; but while such arrangements require twice the number of relief-valves, (one at each end of the cylinder,) they do not effect the purpose for which my invention is designed. Therefore I do not broadly claim the use of relief-valves on engine-cylinders; but

I claim as my invention- In a locomotive-engine, the combination, with the steam-chest of an engine-cylinder,

of an automatic relief-valve located intermediately between the slide-valve and throttlevalve, and arranged to operate as and for the purpose herein specified.

, ROBERT C. BLAGKALL. Witnesses:

Tnos. W. LARWOOD, WILLIAM H. Low.