Improvements in Machinery for Producing Motive Power and for Compressing Gases.
Year: 1892

page_text: Date of Application, 1st June, 1892-Accepted, 9th July, 1892
COMPLETE
SPECIFICATION.
Improvements in Machinery for Producing Motive Power and for
Compressing Gases.
I WILLIAM HENRY NORTHCOTT of Hatcham Ironworks Pomeroy Street New
Cross London S.E. Engineer do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
My improvements relate to arrangements of cylinders, pistons and valves whereby
steam and other gaseous fluids may be expanded or compressed by one or more
stages. The drawings show the arrangements suitable for expanding steam in
the production of motive power, but the general construction of the apparatus is
the same for compressing gases, a different setting of the valve only being
necessary.
My single stage engine is shown at Fig. 1 where a is the cylinder having an
annular piston b and a central valve c. Steam is admitted at d to a central valve
chest projecting downwards from the top cylinder-cover, and having a steam port
close under the top cover, and an open mouth close above the lower cover of the
cylinder.
The annular piston 6 has two piston rods e, e, which after passing through
glands are coupled to the crank pin in the usual way. The valve spindle passes
through a gland either above or below the valve piston and may be actuated in
any convenient manner.
In working when the valve-piston comes below the steam port, steam from d
passes to the top side of the piston 6 which is forced down to the bottom of the
cylinder. Meanwhile the valve-piston having cut off steam by covering the steam
port, passes above the port and thus opens the port to the underside of the
piston b. The steam now escapes into the space under the piston and thence off to
the atmosphere or condenser at the exhaust pipe f.
Instead of the valve chest being made as in Fig. 1, it may be formed as part
of the piston as shown at Fig. 2. Either Fig. 1 or Fig. 2 may be compounded
by placing two or more such cylinders of suitable sizes alongside one another, or
opposite each other, or radially, and passing the same steam from one cylinder to
the other as in stage expansion engines of common construction. But I prefer to
compound the engine by combining two or more cylinders as shown in Fig. 3.
Here the steam after passing through a cylinder such as shown in Fig. 1, is
admitted by a valve piston C to the top of a piston B in a second larger cylinder A,
and thence off by the exhaust orifice f. Fig. 3 shows a two stage engine but a
three stage or four stage engine may be formed by combining three or four
cylinders respectively after the manner of Fig. 3.
Sometimes with the compound engine, I place the valve outside as shown at
Fig. 4 which is a triple compound engine of this construction. A two or four
stage engine may be formed in the same way but a single stage engine of this style
is not claimed.
Either of the arrangements may be made double acting by duplication after the
manner shown at Fig. 5, but instead of this being a common exhaust pipe as shown
there may be a common steam pipe.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. For the purposes named the several combinations of cylinder, piston and
valve herein described.
2. The improved machinery for producing motive power and compressing gases
substantially as described.
Dated this 31st day of May 1892.
WILLIAM HENRY NORTHCOTT.