IMPROVEMENTS IN INDICATORS FOR STEAM ENGINES
Year: 1880

page_text: LETTERS PATENT to Herbert John Haddan, of the Firm of Herbert and
Company, Solicitors of Patents, of 67, Strand, in the City of Westminster,
Civil Engineer, for an Invention of "IMPROVEMENTS IN INDICATORS FOR
STEAM ENGINES." A communication from abroad by George Hannibal Crosby,
"
PROVISIONAL SPECIFICATION left by the said Herbert John Haddan at the
Office of the Commissioners of Patents on the 21st May 1880.
HERBERT JOHN HADDAN, of the Firm of Herbert and Company, Solicitors
of Patents, of 67, Strand, in the City of Westminster, Civil Engineer.
IMPROVEMENTS IN INDICATORS FOR STEAM ENGINES." A communication from
abroad by George Hannibal Crosby, of the State of Massachusetts, United States
of America.
The Invention relates to the rod of the piston of the steam cylinder of indicators,
such as I secured Letters Patent for in 1879, No. 4045, and consists in making such
tubular, and to open at its lower end into or near such end to communicate with
the steam space of the cylinder, and provided at its upper end or between its ends
with a partition or stop to prevent the steam from passing entirely through the
rod or escaping from it at its upper end. The said stop I usually form by boring
the rod from each toward the opposite end of it, until the two bores nearly meet ;
such bores varying in length so as to bring the stop at or near the head of the
cylinder when the piston is at or near its lowest position in the said cylinder. In
this kind of indicator as the pressure of steam in the cylinder varies materially
during the upward stroke of the indicator piston, it becomes very necessary for the
obtaining of good registry that the piston should move rectilinearly and with as
little friction as possible; therefore it is a matter of importance that the piston rod
should be kept well lubricated, or that the lubricating material should not be become
stiff or hard so as to impede the movement of the piston rod in the head of the
cylinder. It also is very necessary to have as light a rod as possible consistent
with the strength or stiffness necessary to prevent it from springing or bending
laterally during its sudden upward movement. It has been found that by making

page_text: the rod tubular, as described, instead of solid throughout its length, it may be
larger in diameter, comparatively speaking, and yet be as strong if not stronger,
and by having its bore open into the steam space of the cylinder so as to enable
the steam to pass up within the rod and heat it, the lubricating material is rendered
softer and caused to operate to better advantage, as in the case of it becoming stiff
or hardening upon the rod, such material will be inelted or softened by the heat.
In order to prevent the rod when very thin from collapsing when the steam in the
cylinder may be condensed, the stop to prevent the emission of steam from tho
upper end of the rod should be placed as low down in the rod as may be possible
consistent with securing the necessary heating of the rod. One or more minute
holes lead from the foot of the upper bore of the piston rod outwardly through the
rod, they being for the purpose of enabling the said upper bore to contain a
lubricating material, such as tallow, for instance; which on being heated by the
steam let into the lower bore will become softened or limpid and flow out upon the
outer surface of the piston rod, thence down the same to and upon the piston head,
whereby both rod and head may be lubricated as occasion may require.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Herbert John Haddan in the Great Seal Patent Office on the 20th.
November 1880.
HERBERT JOHN HADDAN, of the Firm of Herbert and Company, Solicitors
of Patents, of 67, Strand, in the City of Westminster, Civil Engineer.
"IMPROVEMENTS IN INDICATORS FOR STEAM ENGINES." A communication from
abroad by George Hannibal Crosby, of the State of Massachusetts, United States
of America.
The Invention relates to the rod of the piston of the steam cylinder of indicators,.
such as I secured Letters Patent for in 1879, No. 4045, and consists in making such
tubular, and to open at its lower end into or near such end to communicate with
the steam space of the cylinder, and provided at its upper end or. between its ends
with a partition or stop to prevent the steam from passing entirely through the
rod or escaping from it at its upper end. The said stop I usually form by boring
the rod from each towards the opposite end of it, until the two bores nearely meet;
such bores varying in length so as to bring the stop at or near the head of the
cylinder when the piston is at or near its lowest position in the said cylinder. In
this kind of indicator as the pressure of steam in the cylinder varies materially
during the upward stroke of the indicator piston, it becomes very necessary for the
obtaining of good registry that the piston should move rectilinearly and with as
little friction as possible; therefore it is a matter of importance that the piston rod
should be kept well lubricated, or that the lubricating material should not become
stiff or hard so as to impede the movement of the piston rod in the head of the
cylinder. It also is very necessary to have as light a rod as possible consistent
with the strength or stiffness necessary to prevent it from springing or bending
laterally during its sudden upward movement. It has been found that by making
the rod tubular, as described, instead of solid throughout its length, it may be
larger in diameter, comparatively speaking, and yet be as strong, if not stronger,
and by having its bore open into the steam space of the cylinder so as to enable
the steam to pass up within the rod and heat it, the lubricating material is rendered
softer and caused to operate to better advantage, as in the case of it becoming stiff
or hardening upon the rod, such material will be melted or softened by the heat.
In order to prevent the rod when very thin from collapsing when the steam in the
cylinder may be condensed, the stop to prevent the emission of steam from the
upper end of the rod should be placed as low down in the rod as may be possible
consistent with securing the necessary heating of the rod.
In the Drawing
A denotes the cylinder, C the piston, and B its rod, such rod being bored in
opposite directions from its two ends, as shown at a, b, the bores not meeting, but
being insulated from one another by the stop c. The actuating spring of the piston
is shown at D, and the piston rod head at E, such head being secured upon the
rod; the screw e for receiving the said head having upon it a check nut f, as shown.
Another advantage of having the rod bored in opposite directions, as described, is
that such enables the rod and piston head when screwed together to be centered in
a lathe and turned concentrically therein, the centers of the lathe being inserted in
the bored ends of the rod. One or more minute holes lead from the foot of the
upper bore of the piston rod outwardly through the rod, as represented at t, they
being for the purpose of enabling the said upper bore to contain a lubricating
material, such as tallow, for instance, which on being heated by the steam let into
the lower bore will become softened or limpid and flow out upon the outer surface
of the piston rod, thence down the same to and upon the piston head, whereby both
rod and head may be lubricated as occasion may require.

page_text: 1. The indicator piston rod as tubular, and opening at its lower end into or there
communicating with the steam space of the cylinder, and provided at its upper end
or between its ends with the stop, as described, to prevent the steam from escaping
at the upper end of the rod, all being substantially as and for the purpose or
purposes set forth.
2. The piston rod as bored or tubular provided with the stop, substantially as
described.
3. The piston rod as provided with a lubricant reservoir and educt or educts
thereof, substantially as set forth.
4. The piston rod as provided with a lubricant reservoir and one or more educts
thereto as set forth, and also arranged with a steam receiving bore or space
arranged in it, the said rod, and below the said reservoir and to communicate with
the steam space of the cylinder, as described.
In witness whereof, I, the said Herbert John Haddan, have hereunto set my
hand and seal, this Twentieth day of November, A.D. 1880.
TT T
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