US1335589A - Steam-engine of the double-cylinder type - Google Patents

Description

J. G. McKEAN.

STEAM ENGINE OF THE DOUBLE CYLTNDER TYPE.

APPLICATION FILED JUNEZ, I917- Patented Mar. 30, 1920.

1702.11, G HGKGCUU.

JOHN G. McKEAN, or WHITLEY BAY, ENGLAND.

STEAM-ENGINE OF THE DOUBLE-CYLINDER TYPE.

Specification of Letters Patent.

Patented Mar. 30, 1920.

Application filed June 2, 1917. serial No. 172,533.

To all whom z'tmay concern:

Be it known that I, JOHN-GRAVES Mo- KEAN, a subject of the King of Great Britain and Ireland and the Isle of Man, and a resident of WhitleyBay, Northumberland, England, have invented new and useful Improvements in Steam-Engines of the Double-Cylinder Type, of which the following is a specification.

This invention has reference to improvements in steam engines of the double cylinder type and consists in the provision of means comprising a contracted or ejector throat which is formed at the junction of two branch pipes, one connected to the exhaust port of each cylinder, with a common exhaust pipe so that the energy contained in the steam at the terminal pressure in one cylinder is utilized to create for the latter part of the stroke a less absolute back pressure on the piston of the other cylinder than that existing in the region to which the cylinders finally exhaust, provided that this region does not contain a perfect vacuum.

According to this invention branch exhaust pipes from the cylinders of a double cylinder engine, preferably having cranks at right angles or approximately so, or an engine in which the movements of the pistons would give the same results, such as pumping engines of the WVorthington type, are connected to a common exhaust pipe; a

contracted or ejector throat being formed at the junction of said pipes, the cross sectional areas of the throat being less than the cross sectional area of the said branch pipes. The steam contained in the cylinder, the piston of which has completed its stroke and which is at a higher pressure than that existing in the common exhaust pipe which is open to the space in front of the piston of the other cylinder passes through this throat so that for the latter part of the stroke the back pressure in front of the piston of said other cylinder is reduced.

In order that others skilled in the art to which my invention relates may properly understand the same I havehereunto ap- V two cylinders of a steam engine in which the one piston is at the end of its stroke-while the other piston is at the middle of its stroke.

Fig. 2 illustrates, also in diagram form,

the exhaust from each cylinder connected to Y decidedly advantageous.

a common exhaust pipe fitted or constructed according to the improvements of this in vention.

Referringv to these drawings In carrying this invention into effect or practice the ejector consists of a branch pipe, (1. and 22 connected from the exhaust port of each cylinder a and b to a common exhaust pipe 0, having at the junction of said two branch pipes, a and 6 a contracted or ejector throat, d, the cross sectional areas of said branch pipes also being contracted toward the said junction.

In slow running engines, valves e, preferably of the ball type, and with lugs or the like, f, to limit the lift, may be placed between the exhaust ports and the throat of the ejector, d, in order to prevent the return of the higher pressure in the exhaust pipe, due to the weakening action of the ejector when the exhaust operating it falls in pressure.

The ejector action when the steam is excylinder first uncovers the port. At this point, the steam pressure will be that due to the terminal pressure in the cylinder, and this pressure energy will be converted into kinetic energy at the throat of the ejector 03, thereby causing a high velocity at that point with consequently increased ejecting power. As the exhaust remains open, the pressure will drop, as will also the velocity past the throat of the ejector, and consequently the ejecting power will be decreased. Were it not for the ejector action, the back pressure in the other cylinder would be equivalent to the pressure existing in the common exhaust pipe. It therefore follows that when the ejector action weakens, the steam in the powerful when the exhaust valve of that common exhaust pipe will tend to flow back The placing of valves before the throat prevents this back-flow taking place. In high speeds, the inertia of the exhaust steam combined with the divergent common exhaust tends to prevent this back-flow taking place, but at low speeds, the provision of the valves, as herein illustrated and described, is

The method of operation is as follows One piston a being at-the end'of its stroke, the valve opens to exhaust and steam V initially at the terminal cylinder pressurefiows up exhaust pipe, a and passing the throat (Z, induces a flow of steam through the exhaust pipe 79 of the other cylinder 6. This latter exhaust pipe if, being connec ed to the cylinder, 6, the piston 6 of which is. say, at half strokeand its valve being still open to exhaust the back pressure on this piston, 12 is reduced. This action takes place alternately between the two cylinders aand b,from each end.

' hat I'claim and desire to secure by Letters Patent is 1. In a steam engine, branch exhaust pipes joined to a common exhaust pipe, the cross sectional area at the junction of said pipes being less than the cross sectional area of said branch pipes and non-return Valves located in Said branch pipes. v a

2. In a steam engine, branch exhaust p pes joined to a common exhaust pipe and having their cross sectional areas contracted toward the junction of said pipes, in combination with non-return valves in said branch pipes.

In testimony whereof, I have signed myname to this specification, in the presence of two subscribing witnesses. i

' JOHN G. McKE-AN. Witnesses A. Oocnnmm MALCOLM Mo, 'ILLAN.

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