AN IMPROVEMENT IN THE CONSTRUCTION OF A SLIDING DRAWER, APPLICABLE TO ALL STEAM ENGINES EITHER FIXED OR LOCOMOTIVE, FOR THE DISTRIBUTION OF STEAM AËRIFORM OR LIQUIDS, USED EITHER AS A MOTIVE POWER, OR FOR ANY INDUSTRIAL OF ARTISTIC PURPOSE
Year: 1857

page_text: to enry Trappes, of Manchester, in the County of
Lancaster, Gentleman, for the Invention of "AN IMPROVEMENT IN THE
CONSTRUCTION OF A SLIDING DRAWER, APPLICABLE TO ALL STEAM ENGINES EITHER
FIXED OR LOCOMOTIVE, FOR THE DISTRIBUTION OF STEAM AËRIFORM OR LIQUIDS,
USED EITHER AS A MOTIVE POWER, OR FOR ANY INDUSTRIAL OF ARTISTIC PURPOSE."
-A communication.
CONSTRUCTION OF A SLIDING DRAWER, APPLICABLE TO ALL STEAM ENGINES EITHER
FIXED OR LOCOMOTIVE, FOR THE DISTRIBUTION OF STEAM AËRIFORM OR LIQUIDS,
USED EITHER AS A MOTIVE POWER, OR FOR ANY INDUSTRIAL OF ARTISTIC PURPOSE."
-A communication.
ealed the 27th October 1857, and dated the 16th May 1857.
PROVISIONAL SPECIFICATION left by the said Henry Trappes at the
Office of the Commissioners of Patents, with his Petition, on the
16th May 1857.
I, HENRY TRAPPES, of Manchester, in the County of Lancaster, Gentleman,
do hereby declare the nature of the said Invention for "AN IMPROVEMENT IN
THE CONSTRUCTION OF A SLIDING DRAWER, APPLICABLE TO ALL STEAM ENGINES EITHER
FIXED OR LOCOMOTIVE, FOR THE DISTRIBUTION OF STEAM AËRIFORM OR LIQUIDS, USED
EITHER AS A MOTIVE POWER, OR FOR ANY INDUSTRIAL OR ARTISTIC PURPOSE,"
municated to me by a foreigner residing abroad, to be as follows:-
In all steam engines the agent, which is the steam, is introduced into the
body of the pump, and is evacuated from it by the means of a special organ,
to which the name of drawer has been given, by reason of its resemblance to
an ordinary drawer put in motion. This drawer is fitted to a smooth plate, to
which it is in contact, by its lips or edges, its hollow part being turned against
the plate. Its purpose or office is to cover and uncover alternately the aper-
tures called lights made in the plate to give passage to the steam to the body
of the pump and in its escape therefrom.

page_text: To perform these functions, the drawer is subjected to a forward and retro-
grade movement, which is communicated to it by a rod put into motion by an
excentric or otherwise. Before the steam from the boiler reaches the aper-
tures or lights made in the plate, it enters in the first instance into the capacity
or closed space which covers the drawer. This closed space is the steam
chamber of the drawer. In order to prevent any part of the steam to pass
immediately from the boiler to the escape without having first performed its
functions, it is necessary that the lips or edges of the drawer should be very
smooth and closely fitted against the plate during the whole of the movement
of the drawer. This fitting or application is effected by means of the constant
pressure of the steam which takes place on every part of the steam chamber
of the drawer, and consequently on the drawer itself, which constantly covers
the opening of the escape where its hollow space communicates with the
atmosphere or condenser. The drawer is thus placed between two opposite
pressures, the difference between which increases in proportion to the height
of the pressure at which the engine is worked. This difference of pressure is
of course in proportion to the size of the surface of the drawer which receives
it and the pressure of the steam upon it; hence it follows that the action
to be overcome in order to put the drawer in motion is generally considered
to be equal to one sixth part of the power of the engine itself. It can be
readily understood that so great a friction must cause a considerable wear and
tear of the surfaces upon which it acts, requiring frequent repairs thereof,
necessarily resulting in frequent stoppages of the working of the engine. It'
is proposed by the Invention herein-after described to effect a saving as far as
may be of the loss of power, the cost of repairs, and the loss of time above
referred to.
The drawer heretofore known and used in steam engines for the distribution
of steam divides the steam chamber thereof into two compartments; one of
which, usually the largest, is above the drawer, and receives the steam coming
from the boiler; it is the introductory chamber of the steam. The smaller
compartment is the hollow part of the steam chamber which conducts the
steam to the escape; this is the escape compartment.
The lips or edges of the drawer, heretofore known and used in steam engines
bear upon a plane surface, and are parallel to the motion of the drawer. In
the sliding drawer, the subject of the present Invention, the lips or edges
thereof surround it, and are perpendicular to the direction of its, motion, and
the parallel lips or edges. heretofore used are suppressed or done away with;
and the steam chamber of such last-mentioned drawer is divided into three
compartments (instead of two compartments, as in the drawer heretofore

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Trappes in the Great Seal Patent Office on the
3rd November 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
TRAPPES, of Manchester, in the County of Lancaster, Gentleman, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of May, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Henry Trappes, Her special licence that I, the said Henry Trappes,
my executors, administrators, and assigns, or such others as I, the said Henry
Trappes, my 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 "AN IMPROVEMENT IN THE CON-
STRUCTION OF A SLIDING DRAWER, APPLICABLE TO ALL STEAM ENGINES EITHER FIXED
OR LOCOMOTIVE, FOR THE DISTRIBUTION OF STEAM AERIFORM OR LIQUIDS, USED EITHER
AS A MOTIVE POWER, OR FOR ANY INDUSTRIAL OR ARTISTIC PURPOSE," (communi-
cated to me by a foreigner residing abroad,) upon the condition (amongst
others) that I, the said Henry Trappes, my executors or administrators, by an
instrument in writing under my, 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 I, the said Henry Trappes, do hereby declare
the nature of my 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 all steam engines the agent, which is the steam, is introduced into
the body of the pump or cylinder, and is evacuated or exhausted from it
by the means of a special organ, to which the name of drawer or slide

page_text: valve has been given; this drawer or slide valve is fitted to a smooth plate,
to which it is in contact, by its lips or edges, its hollow part being turned
against the plate. Its purpose or office is to open and shut alternately
the lights or steam ports made in the plate to admit the steam into the
body of the pump or cylinder and to exhaust it therefrom. To perform
these functions, the drawer or slide valve is subjected to a forward and retro-
grade movement, which is communicated to it by a rod, put into motion by
an eccentric or otherwise. Before the steam from the boiler reaches the
lights or steam ports it enters in the first instance into the capacity or closed
space which covers the drawer or slide valve. This closed space is the steam
chamber or steam chest. In order to prevent any part of the steam to pass
immediately from the boiler to the escape or exhaust without having first per-
formed its functions, it is necessary that the lips or edges of the drawer or
slide valve should be very smooth and closely fitted steam-tight against the
plate during the whole of movement or stroke of the drawer or slide valve.
This fitting or application is effected by means of the constant pressure of the
steam which takes place on every part of the steam chamber or chest, and
consequently on the drawer or slide valve itself, which constantly covers the
opening of the escape or 'exhaust where its hollow space communicates with
the atmosphere or condenser. The drawer or slide valve is thus placed between
two opposite pressures, the difference between which increases in proportion to
the pressure at which the engine is worked. This difference of pressure is
of course in proportion to the size of the surface of the drawer or slide valve
which receives it and the pressure of the steam upon it The action or resist-
ance to be overcome in order to put the drawer or slide valve in motion is
generally considered to be equal to one sixth part of the power of the engine
itself. It can be readily understood that so great a friction or resistance
must cause a considerable wear and tear of the surfaces upon which it acts,
requiring frequent repairs thereof, necessarily resulting in frequent stoppages
of the working of the engine. It is proposed by the Invention herein-after
described to effect a saving so far as may be of the loss of power, of the costs,
repairs, and of the loss of time above referred to.
The drawer or slide valve heretofore known and used in steam engines
divides the steam chamber or steam chest thereof into two.compartments;
one of which, usually the largest, is above the drawer or slide valve, and
receives the steam coming from the boiler; it is the introductory chamber
of the steam into the cylinder. The smaller compartment is the hollow
part of the steam chamber or steam chest which conducts the steam to the
escape or exhaust; this is the exhaust compartment.

page_text: The lips or edges of the drawer. or slide valve heretofore known and used in
steam engines usually bear upon a surface, and are parallel to the motion of
the drawer or slide valve.
In the sliding drawer or slide valve, the subject of
the present Invention, the lips or edges thereof surround it, and are perpen-
dicular to the direction of its motion, and the parallel lips or edges heretofore
known and usually used are suppressed or done away with; and the steam
chambers or steam chest of such last-mentioned drawer is divided into three
compartments instead of two compartments, as in the drawer or slide valve
heretofore known, the centre compartment of which communicates with the
steam escape or exhaust, and the two extreme compartments of which then
become the steain introducers.
The following is the explanation of the accompanying Drawing, that is
to say:-
Figure 1 represents the longitudinal section of the sliding drawer or slide
valve, the subject of the said Patent. A is a cylinder, either hollow or solid;
"A', A", are the working parts which form the slide valve;" T is the slide valve
rod of the drawer or slide valve. Figure 2 represents the end of the drawer
or slide valve on the side of the slide valve rod. Here the working part is
square. Figure 3 represents the lower part of the steam chamber or steam
chest; Figure 4 represents the section thereof; and Figure 5 represents the
upper half of such steam chamber or steam chest, and shewn in Figure 6 the
section thereof. The two halves of the said steam chamber or steam chest are
tightly fitted by smooth surfaces to each other, so as to be steam-tight, and the
sliding drawer or slide valve must be made to fit exactly into the interior space
thereof, as shewn in Figures 7, and 8. C, C, in Figures 3 and 7, represent
the lights or steam ports leading into the cylinder, and B represents the steam
escape or exhaust. In order to facilitate the passage of the steam, a small
space must be allowed in the steam chamber at each light or steam port all
round the drawer or slide valve. Suppose the steam enters through the pipe
marked V in Figure 7, it will be seen that in order to fill the whole steam
chamber or steam chest the steam must pass through the hollow slide valve
A to arrive at the compartment near the rod thereof, where it finds the tight
or steam port C to pass upon the piston; but during this operation the steam
from the piston passes out through the light or steam port C, fills the inter-
vening compartment which surrounds the cylinder A, and reaches the escape
or exhaust pipe E. It is apparent that in this passage of the steam the drawer
or slide valve is subjected at each extremity thereof to equal and opposite
pressures. The same pressure takes place in the whole surface of the cylinder
A, as well on the exterior as the interior thereof. When the drawer or slide

page_text: valve is moved to and fro by means of its rod, so that the parts A¹ and A³
open and shut the lights or steam ports, it is apparent that the steam will take
an opposite direction to that it had before taken, but the effect of the "pres-
sure on the drawer or slide valve will be the same, which will still keep its
equilibrium in the steam. To diminish the friction, grease cocks g, g, are
add, as shewn in Figure 7.
The peculiar of this method of distributing steam is, that the distributive
organ or agent is subjected to an equal pressure of steam upon all its opposite
parts, and therefore finds itself in equilibrium in the midst of the steam. The
result of this disposition is, therefore, the complete liberty of the action of the
distributor or slide valve, requiring no other power to move it than the power
required to move the rod passing through the stuffing box T'.
This method of distributing steam is applicable to all steam engines, either
locomotive, stationary, or marine. It is also applicable to any engines for the
distribution of aeriforms or gases used as a power.
In witness whereof, I, the said Henry Trappes, have hereunto set my
hand and seal, this Fifth day of October, in the year of our Lord
One thousand eight hundred and fifty-seven.
HENRY TRAPPES. (L.S.)