IMPROVEMENTS IN AND CONNECTED WITH VALVES FOR STEAM AND OTHER ENGINES
Year: 1877

page_text: LETTERS PATENT to William Bow, of the Firm of Bow, M°Lachlan, and
Company, of Paisley, in the County of Renfrew, North Britain, Engineers, for
the Invention of "IMPROVEMENTS IN AND CONNECTED WITH VALVES FOR STEAM
AND OTHER ENGINES."
Sealed the 12th March 1878, and dated the 15th September 1877.
PROVISIONAL SPECIFICATION left by the said William Bow at the Office
of the Commissioners of Patents on the 15th September 1877.
WILLIAM BOW, of the Firm of Bow, M°Lachlan, and Company, of Paisley, in the
County of Renfrew, North Britain, Engineers. "IMPROVEMENTS IN AND CONNECTED
WITH VALVES FOR STEAM AND OTHER ENGINES."
This Invention has for its object to simplify the construction and working of the
valves of steam and other engines, and of the parts immediately connected with
such valves.
One improvement consists in using a slide valve, resembling what is known as a
double-ported valve, in combination with a plate, interposed between the valve and
the cylinder port face; such plate having ports directly through it, and being
adjustable by means of a rod passing through a stuffing box to the outside of the
valve casing, or in any other convenient way.
The motion of the engine is reversed by adjusting the interposed plate, which
may be termed the port plate, so that the valve may be worked by a single
eccentric for both directions of motion, instead of the double eccentrics and link
motion or other reversing gear commonly used.
The cylinder port face is made with double ports, and at one side the port plate
is made with a single port, to which the steam has access only through one of the
inner ports of the valve, and not also from the outside of the valve as hitherto usual
with double-ported valves. If the port plate is adjusted with its port at one side
over the outer one of the two cylinder passage ports steam gets into the passage
when the valve moves towards that side, and vice versa. At the other side the port
face requires to be made with two ports, in order to get the corresponding action;
or there may be two separate port plates like each other, but adjustable both
[Price 6d1

page_text: outwards or both inwards for reversing; or again, the ports may be inclined, and
the port plate or plates be adjusted transversely.
By a further improvement a second plate, which may be termed a cut-off plate, is
combined with the other parts, being interposed between the valve and the port
plate. This cut-off plate has ports formed directly through it corresponding with
the ports of the cylinder passages, and it is made with projections to be moved by
the valve at each end of its stroke; or it may be moved by a rod passing out
through a stuffing box to external gear.
The period of cutting off the steam and other phases of the valve's action are
determinable by suitably proportioning this cut-off plate.
It may also be applied with advantage between a single-ported or common slide
valve and a reversing plate, with direct and indirect passages, such as are described
in the Specification of Letters Patent granted to William Fair and the present
applicant, and dated 24 September 1872 (No. 2817).
The present improvements are applicable to engines worked by steam or other
fluid under pressure, whether the engine details are separate and distinct, or are
combined with other machinery.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Bow in the Great Seal Patent Office on the 14th March
1878.
WILLIAM BOW, of the Firm of Bow, McLachlan, and Company, of Paisley, in the
County of Renfrew, North Britain, Engineers. "IMPROVEMENTS IN AND CONNECTED
WITH VALVES FOR STEAM AND OTHER ENGINES."
My said Invention has for its object to simplify the construction and working of
the valves of steam and other engines, and of the parts immediately connected with
such valves.
One improvement consists in using a slide valve, resembling what is known as a
double-ported valve, in combination with a plate interposed between the valve and
the cylinder port face; such plate having ports directly through it, and being
adjustable by means of a rod passing through a stuffing box to the outside of the
valve casing, or in any other convenient way.
The motion of the engine is reversed by adjusting the interposed plate, which
may be termed the reversing port plate, so that the valve may be worked by.a
single eccentric for both directions of motion, instead of the double eccentrics and
link motion or other reversing gear commonly used.
By a further improvement a second plate, which may be termed a cut-off plate, is
combined with the other parts, being interposed between the valve and the
reversing port plate. This cut-off plate has ports formed directly through it
corresponding with the ports of the cylinder passages, and it is made with pro-
jections to be moved by the valve at each end of its stroke; or it may be moved by
a rod passing out through a stuffing box to external gear.
The period of cutting off the steam and other phases of the valve's action are
determinable by suitably proportioning this cut-off plate.
It may also be applied with advantage between a single-ported or common slide

page_text: valve and a reversing plate, with direct and indirect passages, such as are described
in the Specification of Letters Patent granted to William Fair and me, the said
William Bow, and dated 24 September 1872 (No. 2817).
My present improvements are applicable to engines worked by steam or other
fluid under pressure, whether the engine details are separate and distinct, or are
combined with other machinery.
And in order that my said Invention and the manner of performing the same may
be properly understood, I hereunto append a Sheet of explanatory Drawings, to be
herein-after referred to, and representing the application of my improved valve
details to a steam engine cylinder.
In these Drawings the same reference numerals are used to mark the same or
like parts wherever they are repeated.
Figure 1 is a longitudinal section of the cylinder as taken through the port face
and valve casing; and Figures 2, 3, 4, 5, are respectively face views of the cut-off
plate 2, reversing port plate 3, valve 4, and cylinder port face 5.
The valve 4 resembles what is known as a double-ported valve, and the cylinder
port face 5 is made with double ports 6, 7, 8, 9, but the valve 5 admits steam only
from its inner ports 10, 11, and not also at its ends, as is done by an ordinary
double-ported valve.
The reversing port plate 3, which is in contact with the cylinder port face 5, and
has an exhaust port 12 through its middle, has at one end a single port 13 formed
directly through, which communicates with one or other of the cylinder ports 6, 7,
at the same end, according to the position of the reversing port plate. At the other
end the reversing port plate 3 has two ports 14, 15, formed directly through it, and
one or other of these communicates with one or other of the cylinder ports 8, 9, at
the same end, according to the position of the reversing port plate 3; the relative
arrangement of the ports in this plate 3 being such that both outer cylinder
ports 6, 9, are open in one position of the plate 3, both inner ports 7, 8, being then
closed, and vice versa.
I prefer to interpose a plate 2 between the reversing port plate 3 and the valve 4,
even when I do not use such plate to obtain an earlier cut-off of the steam than
would otherwise occur, such plate 2 being stationary, and having ports 16, 17,
18, 19, exactly facing the cylinder ports 6, 7, 8, 9, and also a central port 20 facing
the exhaust port 21 of the cylinder port face.
It will be seen that with a suitable travel of the valve 4 (say 11 inches in the
example delineated, the stroke of the piston being 10 inches), the admissions and
exhausts of steam from the cylinder will take place just as with an ordinary valve
of similar proportions, but that when the reversing port plate 3 is in the position in
which it is shown in Figure 1, the admission takes place at the end towards which
the valve 4 is moved, this being the reverse of what occurs with the ordinary slide
valve. If, however, the reversing port plate is set so as to close the outer cylinder
ports 6, 9, and open the inner ones 7, 8, then the valve 4 will cause the admissions
and exhausts of steam to take place in a reversed manner, or in other words, like an
ordinary slide valve.
When the plate 2 is used as a cut-off plate, it is made as shown, with pro-
jections 22, 23, at its ends; and as the valve 4 approaches each end of its stroke, it,
by acting on one or other of these projections 22, 23, moves the plate 2 in such a
way that the port by which steam is being admitted is closed sooner than it would
otherwise be when the valve 4 returns.
The main valve 4 is worked by a rod 24 passing out through a stuffing box, and
by external gear in the ordinary way, excepting that a single eccentric serves for
both directions of motion. The reversing port plate 3 is moved by means of a
rod 25 passing out through a stuffing box, the rod being connected externally either
to a simple hand lever or other direct hand gear, or to gearing of the kind in use in
steering engines, or in starting engines.
The cut-off plate 2 may be worked by a rod 26 passing through a stuffing box,
instead of by the valve 4; even when it is moved by the valve 4, I prefer to

page_text: have the rod 26 attached to it to steady its movement, and so that the externally
visible rod may show its action.
Instead of the reversing port plate 3 with a single port 13 on one side and two
ports 14, 15, on the other, there may be two such plates, one on each side, with a
single port in it, and the two plates being adjusted both outwards, or both inwards
for reversing; or the cylinder and other parts may be inclined, the traversing port
plate being, in that case, made adjustable transversely.
Having thus particularly described my said Invention, and the manner of
performing the same, I have to state that I do not restrict myself to the precise
details herein described and delineated, but that what I believe to be novel and
original, and claim as the Invention secured to me by the herein-before in part
recited Letters Patent is,-
1. The combination of double cylinder ports with a valve having two admission
ports and three exhaust openings, and with a reversing port plate or its equivalent
arranged to open the two outer cylinder ports together, whilst closing the two
inner cylinder ports, or to open the two inner ports, whilst closing the outer ones,
substantially as and for the purposes herein-before described.
2. The combination of the cut-off plate with the valve, and with a direct-ported
or indirect-ported reversing port plate, substantially in the manner herein-before
described.
In witness whereof, I, the said William Bow, have hereunto set my hand and
seal, this Twelfth day of March, in the year of our Lord One thousand
eight hundred and seventy-eight.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
WILLIAM BOW. (LS)