IMPROVEMENTS IN AND APPLICABLE TO APPLICA TO SLIDE VALVES, PISTONS, AND GLANDS
Year: 1866

page_text: LETTERS PATENT to Thomas Adams, Engineer, and George John Parson,
Gentleman, of Number Five, Duke Street, Adelphi, in the County of
Middlesex, for the Invention of "IMPROVEMENTS IN AND APPLICABLE TO
"
Sealed the 14th August 1866, and dated the 15th February 1866.
PROVISIONAL SPECIFICATION left by the said Thomas Adams and
George John Parson at the Office of the Commissioners of Patents,
with their Petition, on the 15th February 1866.
We, THOMAS ADAMS, Engineer, and GEORGE JOHN PARSON, Gentleman,
both of Number Five, Duke Street, Adelphi, in the County of Middlesex,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
AND APPLICABLE TO SLIDE VALVES, PISTONS, AND GLANDS," to be as follows:-
Our Invention with reference to slide valves consists in constructing the
valve so that the effect of the steam acting on the back of the valve shall be
equal to the effect of the steam acting on the face of the valve, but should
the surfaces acted on by the steam not be opposite each other then the areas
of such surfaces multiplied by the distances of their centres of action from
the centre of the valve (being the leverage with which the steam acts) should
be made equal. The exhaust in a high-pressure engine and the vacuum in a
low pressure engine acts in a similar manner on the surfaces, but in opposite
[directions. The said surfaces formed by spaces on the back and face of the

page_text: valve respectively are proportioned to each other as required by the insertion
of a ring in the back of the valve, the outer edge of which ring determines
the displacement of steam from the back of the valve. This ring is constructed
with a flange on its outer side, the top side of the flange forming a fillet to work
against the door of the valve box or division plate and being equal in area to
the bottom side of the flange. This ring is also constructed and fitted so as to
admit of an equal area of steam space above and below its inner part. The
steam from the boiler will be caused to act over equal areas on the top and
bottom of the flange of the ring, thereby balancing the pressure on the outer
part of the ring; and the recess or steam space at the top of the inner part of
the ring is equal in area to that at the bottom of the same, and the ring is
balanced by the pressure of the exhaust steam acting equally therein.
And our Invention with reference to pistons and glands consists in the use
of wedge-shaped rings for the metallic packing thereof, the expansion of such
rings being regulated by the area of lateral surface exposed to the action.of
steam admitted from the cylinder. By means of the adaptation of the area
of the spaces in the rings to the medium pressure of steam in the cylinder
any undue amount of friction will be avoided.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Adams and George John Parson in the Great Seal
Patent Office on the 14th August 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, THOMAS
ADAMS, Engineer, and GEORGE JOHN PARSON, Gentleman, both of No. 5,
Duke Street, Adelphi, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Ifer Letters
Patent, bearing date the Fifteenth day of February, in the year of our
Lord, One thousand eight hundred and sixty-six, in the twenty-ninth year of
Her reign, did, for Herself, Her heirs and successors, give and grant' unto
us, the said Thomas Adams and George John Parson, Her special licence
that we, the said Thomas Adams and George John Parson, our executors,
administrators, and assigns, or such others as we, the said Thomas Adams
and George John Parson, our executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times
thereafter 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 "Ix-

page_text: PROVEMENTS IN AND APPLICABLE TO SLIDE VALVES, PISTONS, AND GLANDS," upon
the condition (amongst others) that we, the said Thomas Adams and
George John Parson, our executors or administrators, by an instrument in
writing under our, or their, or one of their hands and seals, should par-
ticularly 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 Thomas Adams and George John
Parson, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement, reference being had to the Drawings
hereunto annexed, and to the letters and figures marked thereon (that is to
say):-
:-
Our Invention of "Improvements in and applicable to Slide Valves, Pistons,
and Glands," consists, with reference to slide valves, in constructing the valve
so that the effect of the steam acting on the back of the valve shall be equal
to the effect of the steam acting on the face of the valve, but should the
surfaces acted on by the steam not be opposite each other, then the areas of
such surfaces multiplied by the distances of their centres of action from the
centre of the valve (being the leverage with which the steam acts) should be
made equal. The exhaust in a high-pressure engine, and the vacuum in a
low-pressure engine, acts in a similar manner on the surfaces, but in opposite
directions. The said surfaces formed by spaces on the back and face of the
valve respectively are proportioned to each other as required by the insertion
of a ring in the back of the valve, the outer edge of which ring determines
the displacement of steam from the back of the valve. This ring is constructed
with a flange on its outer side, the top side of the flange forming a fillet to
work against the door of the valve box or division plate, and being equal in
area to the bottom side of the flange. This ring is also constructed and fitted
so as to admit of an equal area of steam space above and below its inner part.
The steam from the boiler will be caused to act over equal areas on the top
and bottom of the flange of the ring, thereby balancing the pressure on the
outer part of the ring; and the recess or steam space at the top of the inner
part of the ring is equal in area to that at the bottom of the same, and the
ring is balanced by the pressure of the exhaust steam acting equally therein.
And our Invention with reference to pistons and glands consists in the use
of wedge-shaped rings for the metallic packing thereof, the expansion of such
rings being regulated by the area of lateral surface exposed to the action of

page_text: provements above referred to.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a plan or horizontal view of a slide valve adapted for a locomotive
engine; Fig. 2 is a vertical section of the steam chest with the valve therein
shewn in its middle position.
A is the valve; B is the bridle; and C; the valve spindle; D is the door of
the steam chest; E is the cylinder face; F, F, are the steam ports in the
cylinder face; G is the exhaust through the door of the steam chest; H is a
ring inserted in the valve for the purpose of effecting the required displace-
ment of steam so as to cause a balance of steam pressure on those parts of
the surfaces of the valve which are not opposite to each other. These sur-
faces are of such relative areas as that the pressure of steam acting on
one side of the valve, on a smaller area, but at a greater distance from the
centre of the valve may be balanced by the pressure of steam acting on the
other side of the valve on a larger area of surface, but at a less distance from
the centre of the valve. This mode of adapting the ring to the valve in order
to effect the required displacement of steam is illustrated by the diagram,
Fig. 3, which shows an approximate mode of calculating the pressures on two
areas of surfaces on the upper and lower sides of the valve, but not opposite
to each other. For the sake of perspicuity only one-fourth portion of the
respective surfaces is taken as an illustration. The curved line in the Figure
is a portion of the circular line of displacement formed by the outer edge of
the ring H, and the triangular enclosure I represents a fourth portion of the
surface of the valve which receives boiler pressure from below only, while the
rectangular enclosure K represents a fourth portion of the surface which
receives boiler pressure only from above. It will be seen that these two
enclosures are formed as shewn in order to facilitate calculation by converting
It will
the segmental line of displacement into a straight line in each case.
also be seen that the area of the enclosure I is greater than that of K, but
that the pressure is exerted at a greater distance on K than on I, and the
calculation shews that the pressure from below on the greater area of surface
I is balanced by the pressure from above on the lesser area K, because the

page_text: leverage with which the pressure is exerted on is proportionany greater
than the leverage with which the pressure is exerted on I.
The formula is as follows:-For the triangular enclosure I,
2××3-20-6718.
2
And for the rectangular enclosure K it is as follows:-
21x1x5=20-6718.
The exhaust also acts equally on the surfaces, but in opposite directions to
the boiler pressure. The ring H is cast larger than the cavity intended to
receive it in the valve A, and a piece of about one-sixteenth of an inch to the
foot diameter is cut out of it; the ring is then drawn together at butt joint,
as shewn at L, Fig. 1, and in that position bored and turned to fit its place
in the valve A. A steady pin, as shewn in Fig. 2, is used to keep the butt
joint in the centre line of motion. Two small springs M, M, are inserted
beneath the ring in order to keep it up to the door of the steam chest while
steam is off. Fig. 4 is
The ring I is constructed with a fillet N, which works against the door D,
and the ring is recessed inside at O. This ring is balanced by the pressure of
steam on it. The steam in the chest acts under the fillet to press it towards
the door D, and although the fillet touches the door there is the same pressure
between its upper surface and the door as if there were a column of steam an
inch thick between them. The fillet is thus balanced; the top and bottom of
the inside of the ring being exposed equally to the action of the exhaust are
also balanced. The recesses a, a, in the face of the valve are for the purpose
of maintaining the film of steam on the bars during high grades of expansion;
they also serve the purpose of lubrication by steam. In inside cylinder loco-
motives a division plate is fitted in the centre between the cylinder faces,
against which plate the rings of the valves work. It is to be observed that
the valve instead of being balanced by steam alone, as above described, may
be unbalanced by steam, and the balance made up by mechanical force and
resistance, such as the application of springs. Fig. 4 is a section of expansion
valves, both occupying their middle position. The valve A' controls the
admission, exhaust, and compression, and the valve regulates the suppres-
sion. Fig. 5 is a plan of the valve A¹. Fig. 6 is a vertical section shewing a
piston and gland with wedge-shaped packing rings adapted and applied
thereto; S, S, are the two packing rings which are pressed outwards against
the inside of the cylinder by the pressure of steam in a vertical direction;
T, T, are rings with recesses or steam spaces U, U, formed in them, by which

page_text: the amount of force pressing on such rings may be regulated according to the
area of the recesses. The amount of force exerted on the rubbing surfaces,
may be regulated by varying the angle of the packing rings. .V, V, are small
holes for admitting steam to the recesses, but steam may also be applied to
the inner side of the rings S, S. Steam may also be applied direct on to the
rings S, S, without the intervention of the rings T, T, and it may be applied
to the whole or any part of the surface. The same description applies to the
gland W, except that in a high-pressure engine the holes V, V, are not
required, and in a condensing engine the atmospheric pressure acts through
them instead of the steam.
Having thus described the nature of the said Invention, and in what manner
the same is to be performed, we hereby declare that we do not claim as of our
Invention any of the parts of slide valves, pistons, and glands represented
and described otherwise than as berein-after stated; but what we do claim as
of our Invention is, with reference to slide valves, the construction of the
valve and ring in such a manner that the effect of the pressures on the different
parts of the surfaces acted upon is equal, as herein-before described; and with
reference to pistons and glands we claim the application thereto of wedge-
shaped packing rings constructed of any suitable angle for the purpose of
applying any required amount of force on the rubbing surfaces, as described.
In witness whereof, we, the said Thomas Adams and George John Parson,
have hereunto set our bands and seals, the First day of August,
in the year of our Lord One thousand eight hundred and sixty-six.
Witness,
WILLIAM SPENCE,
8, Quality Court,
THOMAS ADAMS.
(L.S.)
GEORGE JOHN PARSON. (L.S.)
Chancery Lane, W.C.