MENTS IN STEERING ENGINES AND REVERSING ENGINES, AND IN VALVES FOR THE SAME AND FOR OTHER ENGINES
Year: 1879

page_text: PROVISIONAI, SPECIFICATION left by Robert Bruce Smith at the Office of
the Commissioners of Patents on the 1st April 1879.
ROBERT BRUCE SMITH, of the Firm of Drewsen & Smith, of 101, Saint Vincent
"IMPROVE-
Street, Glasgow, in the County of Lanark, Engineers, North Britain.
MENTS IN STEERING ENGINES AND REVERSING ENGINES, AND IN VALVES FOR
THE SAME AND FOR OTHER ENGINES."
The combined main valve and cut off valve constructed according to this Inven-
tion are especially applicable to steering engines for the rudders of ships, and to
reversing engines for large marine engines, for the purpose of stopping and reversing
said steering and reversing engines in the manner hereinafter set forth, and as a
main distribution and expansion valve in other engines, and are as follows:-
The valve chest or shell containing the main valve and cut off valve is of a
circular cross section, and of a parallel or conical, or partly conical and partly
parallel, longitudinal section, and is cast with or otherwise united to the steam
cylinder. It has steam inlet and steam outlet or exhaust passages, and also ports
and passages leading to each end of the cylinder. I may also put one valve on each
end of the cylinder; thus for the same engine using two valves instead of one
while working steam tight in this shell there is a liner of a form corresponding
with the shell, and passing out through a stuffing box (or not, as I choose); this
liner has suitable ports, and is the cut off valve, and receives a reciprocating motion
from the engine by means of suitable levers attached to it. Within this liner, and
of a form corresponding with it and the shell, and passing out through a stuffing
box, is the main valve, which receives a reciprocating motion from the engine crank
shaft by suitable gear attached to a lever fixed on its outer stem.
At the parallel part of the valve immediately within the stuffing box I admit the
steam through ports to the inside of the main valve, which beyond this is formed
into pockets or narrow passages ending in oblong ports at its working face, which
is in contact with the liner or with the shell itself. If I choose to do without the
liner as a cut off valve, these ports are the same length and shape as the ports in
the liner or in the shell, and they have a sufficient width of bearing surface all
round to keep the valve steam tight when shut, and for the proper cover at the
steam side and exhaust lap of the valve at mid position. These faces I may cast
solid with the valve, whether the description of valve be conical or cylindrical; or
I may make them separate, and attach them to the valve by expansion hollow

page_text: plates of copper, or by springs and packing, as I choose. This main valve is kept
in equilibrium by closing the stem end of the stuffing box, and by making the area
of the closed end equal to the area of the end formed into pockets or passages, or
by making the area of the closed end the greatest I can put a pressure on the valve
to keep it in its seat. The large intervening spaces between the narrow pockets
are for the escape of the exhaust steam at the cylindrical or larger conical end of
the valve to the open air, or to the condenser, or to the low pressure cylinder
(according to the description of engine to which the valve is applied).
Instead of making the liner a cut off valve I make the cut off valve in the form
of a movable ring or sleeve upon the parallel part of the main valve where the
steam is admitted thereinto, and has ports for admitting the steam to the interior
of the main valve when opposite the ports of the latter, and is worked from the
engine crank shaft or otherwise by suitable connections for the cutting off of the
steam from the piston at the required part of the stroke.
The liner cut off valve I employ preferably as a reversing valve in engines for
reversing the valve gear of large engines, and in steering engines for ships where a
defined distance has to be traversed, such as shifting the link in large engines for cut-
ting off or reversing, or as with a rudder moving it from mid position to any required
part, to starboard or to port, and then stopping or going further in the same direc-
tion, or in the reverse. In such cases the liner cut off valve is moved by the
reversing engine or the steering engine, as the case may be, while the main valve
is moved by hand to that position of opening of valve which corresponds to the
distance to which the reversing valve engine has to link up the valve, or reverse
the motion of large engines, or the steering engine has to put the rudder over; and
as the engine thus works to link up the valve, or to put the rudder over, it is also
"closing the steam opening with the cut off valve which was opened by the main or
hand valve until it is closed and the engine is stopped, while the links of the large
engines (or rudder) are in their required positions, and by opening the main valve
by hand a little the links or rudder will be moved a corresponding distance further
over, and if the rudder by any unusual strain or blow from a wave should be sud-
denly shifted to starboard or to port the engine will be moved correspondingly, and
the cut off valve will also be opened and admit steam to bring it back to its original
position. The stout ring or sleeve cut off valve or the parallel steam admission
part of main valve I use as an expansion valve, and both it and the main valve I
use for the proper distribution of the steam in large engines, and are both con-
nected by suitable means to the crank shaft, from which they receive a reciprocal
circular motion or I
i may use the main circular valve (conical or cylindrical) alone
and without the cut off valve, and I may give it its motion from the crank, shaft or
from the engine piston cross head, as I choose.
The steering or reversing engines fitted with the aforesaid valves have the steam
cylinders arranged on bedplate and framing in the usual way; the valve for distri-
buting the steam to the piston is operated by eccentric on crank shaft, or by a
scurved spindle attached to engine crosshead. In the valve for reversing the main
or central valve is worked by hand as required, and the cut off valve by a worm
working in a worm wheel, the worm being fitted on a revolving shaft of the steering
or the reversing engines, and the worm wheel fitted on to the spindle of the cut off
valve.