Improvements in Steam Engines.
Year: 1890

page_text: Date of Application, 22nd July, 1890
Complete Specification Left, 22nd Apr., 189:-Accepted, 23rd May, 1891
PROVISIONAL SPECIFICATION.
Improvements in Steam Engines.
1, JOHN TURNBULL Junior of 255 Bath Street, in the City of Glasgow,
Consulting Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to the construction and arrangement of the valves and
valve gear of steam engines of the type in which induction and eduction of the
steam take place through a single port at each end of the cylinder in proximity to
which port the admission and exhaust valves are situated special features of the
invention consisting in arranging the valves within a single casing at each end
whereby time and labour are economised in boring out the casings and fitting the
valves, and the employment in conjunction with this arrangement of a scroll cam
operated from the engine governor to regulate the period of cutting off the steam,
the exhaust valve being operated by a separate cam or eccentric on the same spindle.
In close proximity to the steam inlet and exhaust port at each end of the cylinder
a cylindrical valve chamber is bored and is fitted with a hollow plug having two
planed faces preferably at right angles to each other serving as seats the one for
the steam admission valve and the other for the exhaust valve. The valve seats
have suitable apertures or orifices formed in them to correspond to the valves which
are preferably of the gridiron sliding type, and these orifices in the case of the
admission valve admit steam from a steam casing common to both valve casings to
and through the valve casing to the cylinder port and in the case of the exhaust
valve provide communication between said port and an exhaust passage leading to
a condenser or to the atmosphere or in the case of compound engines to a low
pressure cylinder. The seat for one valve, preferably the steam inlet valve, is
formed on the outside of the plug whilst the other is formed on the inside and
the valves are operated by levers on separate rocking shafts carried in bearings
formed for the one shaft in the plug and for the other in the steam casing or
other part of the cylinder. The rock shaft, operating the steam admission valve
has fitted on its outer end a bell crank lever one arm of which is connected to
a spring or dash pot whilst the other arm is connected by a link to a cam
piece bearing on and operated by a scroll or other cam on the governor spindle
or a spindle operated from the governor, the scroll cam operating in a well
known manner to regulate the cut off. The links from both admission valves
are connected through the cam pieces so as to be operated from the same cam,
whilst a single cam or eccentric on the same spindle operates both exhaust valves
through links connected to lever arms on the rock shafts provided for said valves.
Dated this Twenty-first day of July 1890.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.
COMPLETE SPECIFICATION.
Improvements in Steam Engines.
I, JOHN TURNBULL, Junior, of 255 Bath Street, in the City of Glasgow,
Consulting Engineer do hereby declare the nature of this invention and in what
nanner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
This invention relates to the construction and arrangement of the valves and
valve gear of steam engines of the type in which, induction and eduction of the

page_text: steam take place through a single port at each end of the cylinder in proximity
to which port the admission and exhaust valves are situated special features of
the invention consisting in arranging the valves within a single casing at each
end whereby time and labour are economised in boring out the casings and
fitting the valves, and the employment in conjunction with this arrangement of
a scroll cam operated from the engine governor, to regulate the period of cutting
off the steam, the exhaust valve being operated by a separate cam or eccentric
on the same spindle.
In the accompanying drawings
Figure 1 is an elevation and Figure 2 a part sectional plan of a steam engine,
constructed in accordance with my invention, and
Figure 3 is a transverse section through the valve casing at one end of the
cylinder.
Figures 4 and 5 are respectively an elevation and part plan of the engine as
fitted with a high speed governor and suitably modified arrangement of scroll
cam gearing.
In close proximity to the steam inlet and exhaust port a at each end of the
cylinder A, a cylindrical valve chamber B is bored and is fitted with a hollow
plug C, having two planed faces b¹ preferably at right angles to each other
serving as seats, the one b, for the steam admission valve D and the other b' for the
exhaust valve E. The valve seats have suitable apertures or orifices formed in
them, to correspond to the valves D E, which are preferably as shown of the
gridiron sliding type, and these orifices in the case of the admission valve admit
steam from a steam casing F, common to both valve casings B, to and through.
the valve casing to the cylinder port a; and in the case of the exhaust valve E
provide communication between said port and an exhaust passage G leading
to a condenser or to the atmosphere or in the case of compound engines to a
low pressure cylinder. The seat for one valve preferably the steam inlet
valve, is formed on the outside of the plug C, whilst the other is formed on
the inside and the valves are operated by levers H and 1 on separate rocking
shafts J and K carried in bearings formed for the shaft K, in the plug and for the
shaft J in the steam casing F or other part of the cylinder.
The rock shaft J
operating the steam admission valve D has fitted on its outer end a bell crank
lever L one arm of which is connected to a spring or dash pot M whilst the other
arm is connected by a link N, to a cam piece O bearing on and operated by a scroll
or other cam P, on the governor spindle Q, as indicated at Figures 1 and 2, or on a
spindle R operated from the main shaft, the cam being raised and lowered by a
lever arrangement V actuated by the governor, as indicated at Figures 4 and 5, the
scroll cam operating in a well known manner, to regulate the cut off. The links N
from both admission valves D are connected through the cam pieces O so as to be
operated from the same cam P, whilst a single cam or eccentric S on the same
spindle operates both exhaust valves E through links T connected to lever arms U
on the rock shafts K provided for said valves.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. Valve gear for steam engines constructed and operated substantially as herein-
before described.
2. In a steam engine of the type set forth the arrangement of a single valve
casing between the inlet and outlet ports of the cylinder and fitted with a hollow
plug having seats for the admission and exhaust valves substantially as described.
Dated the Twenty-first day of April 1891.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.