IMPROVEMENTS IN SLIDE VALVES
Year: 1870

page_text: LETTERS PATENT to George Weir, of Glasgow, in the County of
Lanark, and James Weir, of Liverpool, in the County of Lancaster,
for the Invention of "IMPROVEMENTS IN SLIDE VALVES."
PROVISIONAL SPECIFICATION left by the said George Weir and
James Weir at the Office of the Commissioners of Patents, with
their Petition, on the 14th June 1870.
We, GEORGE WEIR, of Glasgow, in the County of Lanark, and
JAMES WEIR, of Liverpool, in the County of Lancaster, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN, SLIDE
VALVES," to be as follows, that is to say :-
This Invention relates to further improvements and modifications
devised whilst practically working out the Invention described in the
Specification of Letters Patent granted to the present applicants, and
dated 17th December 1869, (No. 3650), and has for its object the
reduction and regulation of the pressure experienced on the back of
ordinary slide valves of various kinds by means or appliances which

page_text: whilst simple, convenient, and satisfactory, can be relied upon under
all the varying conditions as to pressure of steam or other fluid acting
upon the valves.
In dealing with the valves of compound engines the valve of the high-
pressure cylinder may have the pressure on it regulated in the manner
described in the earlier Specification, but in the case of the valve for the
low-pressure cylinder the steam on the back of the valve may be that
which passes into the cylinder, whilst the pressure on the valve is
counterbalanced by steam admitted to spaces under the valve but separate
from the exhaust and cylinder ports. To effect the object this steam
must be of a higher pressure than that on the back of the valve, and is
conveniently obtained in the case of compound engines by taking it
from the boiler or from the high-pressure valve casing, a small regulating
reducing valve being arranged to adapt the supply to the fluctuating
requirements. This contrivance admits of the employment of a smaller
valve and of simpler passages than when the steam entering the cylinder
passes from the interior and not the back of the valve, as in the earlier
arrangement.
The same advantages may be secured in connection with the high-
pressure valves of compound engines, or with the valves of common
(or non-compound) engines by providing steam or other fluid of higher
pressure than the steam or fluid entering the cylinder to act on the under
side of the valve. Steam of the desired higher pressure may be obtained
by means of a small additional boiler, or steam or other fluid may have the
requisite pressure imparted to it by a pump worked by the engine. And
in any of the applications the fluid made to act on the under side of the
valve may be a different fluid from that working the engine. Thus water,
oil, or other liquid may be used in a steam engine, such liquid having
the additional advantage of lubricating the working surfaces of the valve
and port face, and as the lubricating matter thus pumped into cavities
under the valve will find its way in part into the cylinder, other means
of lubricating the cylinder may be dispensed with.
The bigh-pressure valve of a compound engine is also by this Invention
to be balanced by a disposition of the three pressures similar to what is
herein-before described relative to the low-pressure valve, this being
done in the case of a common slide valve (and in an equivalent manner
in other cases) by causing the high-pressure steam to enter from
what is ordinarily the exhaust port to the valve, and thence to the

page_text: cylinder, the intermediate steam from the cylinder exhausting into the
casing and bearing on the back of the valve. The sides of the valve are
made broader than ordinarily and cavities under the sides are put in
communication with the condenser through a regulating valve, so that
the excess of the intermediate pressure on the valve over these cavities
will balance or partly balance the excess of the high pressure in the
opposite direction.
The main features then of the present Invention are, firstly, the
counterbalancing and regulating of the pressure acting on any kind
of slide valve by causing a fluid of a higher pressure than that entering
the cylinder and acting on the back to act on the under side of the valve
by being admitted or forced into spaces in the port face or valve face;
secondly, the using of a lubricating liquid as such high-pressed fluid
for relieving the pressure on the valve; and thirdly, the balancing
of the valves of compound engines by a suitable disposition of three
pressures on each valve.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Weir and James Weir in the Great Seal
Patent Office on the 13th December 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, GEORGE
WEIR, of Glasgow, in the County of Lanark, and JAMES WEIR, of
Liverpool, in the County of Lancaster, send grecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of June, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-third
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto us, the said George Weir and James Weir, Her special
licence that we, the said George Weir and James Weir, our executors,
administrators, and assigns, or such others as we, the said George
Weir and James Weir, our executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and
at all times thercafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for "IMPROVEMENTS IN SLIDE VALVES," upon the

page_text: condition (amongst others) that we, the said George Weir and James
Weir, our executors or administrators, by an instrument in writing
under our, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said George Weir and James Weir,
do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and
ascertained in and by the following statement in writing, reference
being had to the accompanying Drawings, that is to say:-
Our said Invention relates to further improvements and modifications
devised whilst practically working out the Invention described in
the Specification of certain Letters Patent granted to us, and dated
17 December 1869 (No. 3650), and has for its objects the reduction and
regulation of the pressure experienced on the back of slide valves of
various kinds, and also the effective lubrication of the valve face and
port face.
It comprises means or appliances which, whilst simple,
convenient, and satisfactory, can be relied upon under the varying
conditions as to pressure of steam or other fluid acting upon the valves.
And in order that our present Invention and the manner of performing
the same may be properly understood we hereunto append a Sheet of
explanatory Drawings to be herein-after referred to, and representing the
application of our improvements. The same reference numerals are
used to mark the same or like parts in all the Figures in which they are
repeated.
Figures 1 and 2 are sections as at right angles to each other showing
the application of modifications of our improved arrangements to the
valves of a pair of compound or combined high and low-pressure engines.
In dealing with the valves of such engines, the valve of the high-pressure
cylinder 1 may have the pressure on it regulated or more
or less
counterbalanced in the manner described in our earlier Specification
herein-before referred to, or in any of the modes hercin-after described,
whilst in the case of the valve 3 of the low-pressure cylinder 2 the
steam on the back of the valve may be that which passes into the
cylinder, whilst its pressure is more or less counterbalanced by steam
admitted to spaces 4, 4, under the valve, but separate from the exhaust 5

page_text: and cylinder ports 6, 6. Figure 3 is a face view of the port face of the
low-pressure cylinder 2, and the valve shown is of the kind known as
double ported. To effect this object the steam acting in the spaces 1
under the valve must obviously be of a higher pressure than that on the
back of the valve, and is conveniently obtained in the case of compound
engines by taking it from the boiler, or from the high-pressure valve
casing or inlet, or, as shown in the Drawing from the steam jacket space 7.
To carry out this part of our Invention completely the steam for
counterbalancing should pass through a small regulating reducing valve,
as to which reference is herein-after to be made; but in practice it will
probably be preferred on account of simplicity to dispense with such regu-
lating appliance, and to proportion the parts so that whilst the valvo
may not be as completely counterbalanced as possible there will be
no risk of the counterbalancing pressure being too great under any.
circumstances. The counterbalancing to any extent of pressure such
as acts injuriously on ordinary valves is undoubtedly of proportionate
practical advantage, and an improvement only differing in degree from
what may be considered the most complete counterbalancing possible.
The arrangements just described for counterbalancing the low-pressure
valve 3 admit of the employment of a smaller valve and of simpler
passages than when the steam entering the cylinder passes from the
interior of the valve, as in our earlier arrangement.
The same advantages may be secured in connection with the high-
pressure valves of compound engines or with the valves of common
(or non-compound) engines, by providing steam or other fluid of higher
pressure than the steam or fluid entering the cylinder to act on the
under side of the valve. Steam of the desired higher pressure may be
obtained (in the case of large engines, for example,) by means of a small
additional boiler, or steam or other fluid may have the requisite pressure
imparted to it by a pump worked by the engine. And in any of such
applications the fluid made to act on the under side of the valve may be
a different fluid from that working the engine. Thus water, oil, or other
liquid may be used in a steam engine, such liquid having the additional
advantage of lubricating the working surfaces of the valve and port face;
and if lubricating matter is thus pumped into cavities under the valve it
will find its way in part into the cylinder, so that other means of lubri-
cating the cylinder may be dispensed with.
Figures 5 to 8 show the application of one modification of our

page_text: counterbalancing arrangements to a single-cylinder plain horizontal
engine with the valve casing at the side, Figure 5 being a horizontal
section; Figures 6 and 7, vertical sections; and Figure 8 an enlarged
section of the pump for obtaining the increased pressure. Any suitable
known arrangement of pump may of course be used, but the one
shown requires very little power, as after the full pressure is once
attained it only works so far as to make up for any leakage, whilst it is
also so contrived as to be an automatic regulator, or, in other words, so
as to make the counterbalancing pressure greater or less accordingly as
the main steam pressure is more or less. The pump is formed in the
side of the valve casing 8 and contains a differential plunger, the larger
part 9 of which works in a bore or barrel having its inner end open to
the steam in the casing, whilst the smaller part 10 works out through a
stuffing box and is connected to a bell-crank lever 11, which is acted
upon but in one direction only, namely, to push in the plunger by a pin
or projection on the piston rod, cross head, or slide block 12. The
outward movement of the plunger is produced by the pressure of the
steam in the valve casing, but as that pressure is resisted by only the
atmosphere on the portion of the plunger's area corresponding to its
smaller part 10 it produces the required higher pressure on the oil or
other liquid which it forces into the counterbalancing recesses 4, 4, in
the port face, such oil being drawn from an oil cup 13 by each inward
movement of the plunger. With this arrangement it is obvious that
an increase or diminution in the pressure acting in the valve casing
will occasion a corresponding alteration in the counterbalancing pressure
produced by the pump. If preferred, however, this automatic variability
may be dispensed with, and the forcing stroke of a common pump be
effected by means of a weight or spring, the sucking stroke being effected
by any conveniently moving part of the engine; or an adjustable weight
may be used upon the lever 11, as well as the steam pressure on the
plunger end 9.

page_text: head, the pressure due to which, however slight, will so far reduce the
effect of pressure on the back, and in proportion as the head or pressure
of the oil or lubricant is increased, so will there be the greater pressure
relieving effect in addition to the lubricating action. For example,
Figure 9 represents the port face of a vertical cylinder with spaces 4,
for lubricating and counterbalancing, the oil being led into these spaces
by passages and pipes 14 from a double oil cup 13 which may be at any
convenient elevation, a pipe 15 being provided to lead steam to the top
of the lower closed compartment of the cup to replace the oil as it
descends. Or the oil cup 13 may be close down upon the top of the valve
casing, as shown in Figure 10, being arranged to drop the oil inside into
a gutter or internal reservoir 16, from which it descends by passages to
the spaces 4. In cases in which oil or other liquid is led into spaces 4,
for counterbalancing or lubricating the valve, passages or bores may be
formed from the bottoms of those spaces 4 to external cocks, as indicated
at 36, in Figure 9, for blowing out the liquid, and for ascertaining
thereby if the rubbing faces are becoming worn or not, the condition of
the liquid thus blown out being a good criterion of this.
Our Invention further consists in balancing or partially balancing the
high-pressure valve of a compound engine by a disposition of three
pressures similar to what is herein-before described relative to the
low-pressure valve (3, Figures 1, 2,) this being done in the manner
shown in Figures 1, 2, and 4, by causing the high-pressure steam to
enter by a passage 17, and from what is ordinarily the exhaust port 18
to the hollow of the valve 19, and thence to the cylinder 1, whilst the
intermediate steam from the cylinder exhausts into the casing or space 20,
and bears on the back of the valve. The sides of the valve 19 are
made broader than ordinarily, as is also the port face (Figure 4), and
cavities 21 in the latter are put in communication with the condenser by
a pipe 22 leading into the exhaust port 5 of the low-pressure cylinder 2,
or as we prefer it through a regulating valve. In this way the excess of
the intermediate pressure on the back of the valve over these cavities 21
will be balanced or partly balanced by the high pressure in the port 18.
Figure 11 is a section of a form of proportional regulating valve suitable
for the low-pressure arrangement herein-before described with reference
to Figures 1, 2, 3; whilst Figure 12 shows an arrangement suitable
for the high-pressure modification last hercin-before described. In the
•

page_text: former a passage 23 leads the high-pressure steam in between a piston
and valve connected together and of suitably proportioned areas. The
other side of the piston is in communication by the passage 24 with the
intermediate space 20, and if the pressure in that space increases the valve
opens and admits more steam into the passage 25, which leads to the
counterbalancing space 4; if the pressure in the counterbalancing spaces
is ever too great the main valve simply lifts slightly and allows a little
steam to escape. In the high-pressure arrangement, Figure 12, a passage
26 communicating with the counterbalancing spaces 21 (Figure 4) has
in it two valves, one 27 opening into the high-pressure passage 28 and the
other 29 opening from a passage 30 leading to the condenser. The valves
27, 29, are connected by a lever 31 jointed to the middle connecting
part 32 of two pistons or plungers 33, 34, one of which is acted on by
the intermediate pressure in the passage 35 whilst the other is acted on
by the high pressure. If the proportion of the high pressure to the
intermediate pressure should become diminished the pistons 33, 34, will
be lowered, the valve 27 opened and steam admitted to the passage 26,
but if the opposite change takes place the pistons will rise and cause the
valve 29 communicating with the condenser to be opened; the valve 27
or 29 being in either case immediately closed again by the action of the
altered pressure in the passage 20 and between the two pistons.
Having thus particularly described our said Invention and the manner
in which the same is to be performed we have to state that we do not
restrict ourselves to the precise details herein described or delineated,
but that what we believe to be novel and original, and claim as the
Invention secured to us by the herein before in part recited Letters
Patent is,-
1. The balancing or partial balancing of pressure acting on the back
of a slide valve by causing a fluid of a higher pressure to act on the
under side of the valve substantially in any of the modes herein-before
described.
2. The balancing or partially balancing of the slide valves of compound
steam engines by suitably disposing three pressures to act thereon
substantially as herein-before described.
3. The lubricating of slide valves by admitting or forcing oil, water,
or other lubricant into spaces beneath those sides of the valve face.

page_text: which are at right angles to the ports, substantially as herein-before
described.
In witness whereof, I, the said George Weir, on behalf of
myself and the said James Weir, have hereunto set my hand
and seal, this Twelfth day of December, in the year of our Lord
One thousand eight hundred and seventy.