IMPROVEMENTS IN STEAM TRAPS
Year: 1872

page_text: LETTERS PATENT to John Brodie Robertson, of Manchester, in the
County of Lancaster, Engineer, for the Invention of "IMPROVEMENTS
IN STEAM TRAPS."
Sealed the 14th January 1873, and dated the 17th July 1872.
PROVISIONAL SPECIFICATION left by the said John Brodie Robertson
at the Office of the Commissioners of Patents, with his Petition,
on the 17th July 1872.
I, JOHN BRODIE ROBERTSON, of Manchester, in the County of Lan-
caster, Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN STEAM TRAPS," to be as follows:-
. My Invention relates to apparatus suitable to be employed to effect
the discharge of the water arising from the condensation of steam in
steam pipes, drying cylinders, and other bodies or parts of machinery
into which steam is admitted.
:
In apparatus constructed in accordance with my Invention the end
of the discharge pipe or the discharge orifice is fitted with a plug, in

page_text: which are formed ports which communicate with internal passages
formed in the said plug. A shell is fitted to and mounted on the said
plug, and in the said shell ports are formed which communicate with
two passages which lead into a chamber which is connected with and
.sustained by the said shell. A balance weight is formed on or attached
to the said shell or to a lever projecting from the said shell, and the
· arrangement is such as that as the said weight and the said chamber
alternately preponderate the said shell is caused to rock upon the said
plug. One of the ports in the said plug which I will call the first
port remains or may remain open and permits water or water and steam
to flow into the said chamber. The preponderance of the said balance
weight tends to close the other port, which I will call the second port,
the preponderance of the said chamber tending to open the said second
port. The last named port communicates with a passage through which
the water is discharged from the apparatus.
The water flowing through the first port and through one of the
passages enters the said chamber until the said chamber preponderates
over the said balance weight, and the shell is thereby caused to rock
upon the said plug and the second port is opened. The water is now
permitted to flow or is forced by the pressure of steam through a second
passage which communicates with the lower part of the said chamber
and through the said second port. The ports are preferably so pro-
portioned as that before the said chamber becomes sufficiently clear from
water to permit of the escape of steam from the second port the balance
weight will effect the closing of the said port,
The aforesaid shell may be formed with a gland or stuffing box or
with two glands, or stuffing boxes in order to prevent or to lessen the
discharge of water or steam otherwise than through the passages pro-
vided for the said discharge. I may line the said shell with lignum
vitm
1. .
L

page_text: +
•
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of July; in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the 'said John Brodie Robertson, Her special license
that I, the said John Brodie Robertson, my executors, administrators,
and assigns, or such others as I, the said John Brodie Robertson, 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 IMPROVEMENTS
IN STEAM TRAPS," upon the condition, amongst others, that I, the said
John Brodie Robertson, by an instrument in writing under my hand
and seal, 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 John Brodie Robertson, 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 and accompanying .Drawings, that is to
say:
My Invention relates to apparatus suitable to be employed to effect
the discharge of the water arising from the condensation of steam in
steam pipes, drying cylinders, and other bodies or parts of machinery
into which steam is admitted.
! 1
In apparatus constructed in accordance with my Invention the end
of the discharge pipe or the discharge orifice is fitted with a plug in
which are formed ports which communicate with internal passages
formed in the said plug. A shell is fitted to and mounted on the said
plug, and in the said shell ports are formed which communicate with two
passages which lead into a chamber which is connected with and
sustained by the said shell. A balance weight is formed on or attached
to the said shell, or to a lever projecting from the said shell, and the
arrangement is such as that as the said weight and the said chamber
alternately preponderate, the said shell is caused to rock upon the said

page_text: plug. One of the ports in the said plug which I will call the first port
remains or may remain open and permits water or water and steam to
flow into the said chamber. The preponderence of the said balance
weight tends to close the other port which I will call the second port,
the preponderence of the said chamber tending to open the said. second
port. The last-named port communicates with a passage through which
the water is discharged from the apparatus.
.
The water flowing through the first port and through one of the
passages enters the said chamber until the said chamber preponderates
over the said balance weight, and the shell is thereby caused to rock
upon the said plug and the second port is opened. The water is now
permitted to flow or is forced by the pressure of steam through a second
passage which communicates with the lower part of the said chamber
and through the said second port.
And in order that my said Invention may be fully understood I
have attached hereunto a Sheet of Drawings marked with letters of
reference, corresponding marks indicating the same parts in the various
Figures.
In the said 'Drawings Fig. 1 represents a side elevation of a steam
trap constructed in manner according with my said Invention, and
drawn about one quarter of the full size; Fig. 2 is a plan of the valve
portion of the said trap drawn about half the full size; Fig. 3 is a
vertical section on the line A; Fig. 4 a vertical section on the line B;
and Fig. 5 a vertical section on the line C.
In Fig. 1a is the inlet pipe, which conveys water or water and steam
to the trap, and which is in communication with the interior of the
steam chamber or cylinder or cylinders or other body from which water
is to be withdrawn, 6 being the outlet pipe through which the said water
is conveyed from the trap. The pipes a and b are attached to a casting
on which is formed a plug or cylindrical or conical valve seating c, and
on the said plug is mounted a shell d to which are attached the arms e
and which sustain the hollow chamber 9 and the balance weight h,
the said plug being suitably turned and the said shell being bored and
fitted to the said plug with suitable accuracy so as to prevent any
excessive leakage of steam or water from the joint between the said
shell and the said plug. The arm e, a cross section of which is repre-
sented at Fig. 6, is formed with two passages i and k, which communicate.

page_text: .
with corresponding passages and ¹ formed in the shell d. The
passage i communicates with the upper end of the chamber and the
passage with the lower part of the said chamber by means of the
internal pipe 7. The inlet pipe a communicates through a passage a¹
and a port m formed in the plug c with the passage i, as shewn in
Fig. 5. The outlet pipe b communicates through the passage 6¹ with
the port n and through the said port at intervals with the passage k..
The port m remains open at all times during the working of the apparatus,
and permits water or steam or water and steam to flow into the chamber g.
The port n is represented as closed in Fig. 4, but when the chamber g
preponderates over the weight h the shell d rocks on the plug c and
the passage ¹ is thereby brought into communication with the said
port so as to permit water to flow through the said port to the outlet
pipe.
The action of the apparatus may be described as follows:-Supposing
the parts to be in the position represented in the Drawings, and water
to be flowing through the passages a³, ¹, and i into the chamber g, the
accumulation of water in the said chamber will cause the said chamber
to preponderate over the weight h and the shell d will turn on the
plug d, and the port n will thereby be uncovered and water will be
forced by the pressure of the steam out of the said chamber and through
the pipe and the passage k and port n into the passage 6' leading to
the outlet pipe b. This action will continue so long as water continues
to flow into the said chamber, but on the said flow ceasing steam will
enter the said chamber, and water continuing to issue from the said
chamber the level of the water contained in the said chamber will be
reduced until the weight h will preponderate over the said chamber,
when the port n will be covered and the flow of water from the chamber
will cease.
I so proportion and arrange the various parts as that the said port n
will be covered before the water in the chamber has fallen to the level
of the lower end of the pipe l, whereby the discharge of steam through.
the said pipe is prevented.
A slight modification in the form of the shell d is shewn at Fig. 7.
In this example a shell extending around the plug dis not employed,
but the part in which the passages and k¹ are formed rests on the
upper part of the said plug, and is formed with a curved lower surface
to fit upon the said plug.

page_text: When constructed in this manner the moving part of the valve will
work with less friction and will not be so liable to stick or set fast on
the plug.
I do not confine myself to the precise details as herein described, nor
to the exact form of the apparatus as illustrated in the accompanying
Drawings, as variations therein may be made, as for example, the shell d
may be formed or provided with a gland or with glands working on the
plug c in order to prevent or lessen the escape of steam and water from
the joint between the said shell and the said plug, but I prefer to
dispense with such gland or glands as I believe that it or they would
interfere with the action of the apparatus.
Having now fully described and indicated the nature of my said
Invention, and my method of carrying the same into practical effect, I
would in conclusion have it to be distinctly understood that I claim the
apparatus substantially as and for the purpose herein-before set forth
and indicated, the important features of such apparatus being the
chamber connected with a part which is fitted to oscillate on a plug
or valve seating in which are the passages for the inlet and outlet of
water to and from the said chamber.
In witness whereof, I, the said John Brodie Robertson, have here-
unto set my hand and seal, this Sixteenth day of January, in
the year of our Lord One thousand eight hundred and seventy-
three.
Signed and sealed by the said John
Brodie Robertson in the presence
of
EDWARD K. DUTTON,
Agent for the Patentee,
Manchester.
J. B. ROBERTSON. (L.S.)