IMPROVEMENTS APPLICABLE TO SAFETY VALVES AND PRESSURE OR TEMPERATURE GUAGES
Year: 1863

page_text: LETTERS PATENT to James Mash, of Bowden, in the County of Chester,
Engineer, for the Invention of "IMPROVEMENTS APPLICABLE TO SAFETY
VALVES AND PRESSURE OR TEMPERATURE GUAGES."
Sealed the 3rd May 1864, and dated the 10th November 1863.
PROVISIONAL SPECIFICATION left by the said James Mash at the
Office of the Commissioners of Patents, with his Petition, on the 10th
November 1863.
I, JAMES MASH, of Bowden, in the County of Chester, Engineer, do hereby
declare the nature of the said Invention of "IMPROVEMENTS APPLICABLE TO
SAFETY VALVES AND PRESSURE OR TEMPERATURE GUAGES," to be as follows:-
My improvements relate to apparatus applicable to the construction and
working of safety valves and pressure or temperatue guages used and employed
in steam boilers, steam apparatus, and heated air apparatus.
As regards the application of my improvements to safety valves it consists
in constructing and employing, in combination with any known descriptions of
safety valves, cylindrical or other formed vessels containing mercury, having
one or more parts of each expansible upon the application of heat, and
connected with the valves in such manner that upon increase of heat beyond
any predetermined temperature, the valves are lifted from their seats and
steam liberated, the lifting of the valves being thus effected by the expansion
of the mercury contained in the cylinders or other vessels independently of the
loading of the valves by weights as usual. The connections between the

page_text: mercury-containing cylinders or vessels and the safety valves, or the mode of
working may be such that the valves can be opened only by the expansion
of the mercury, or may be such as to permit of opening or raising the valves
from their seats at any time by other means, as by the pressure of steam or
by hand, as is well known. The cylinders or vessels are by preference placed
in the boilers themselves, but may be placed in positions where the steam
would have as free access as practicable to them, in order that the temperature
of the mercury may be affected with facility by any variation of temperature
of the steam.
When I apply my improvements to pressure or temperature guages I
connect the mercury-containing cylinders or vessels with pointers or indexes
upon convenient dials or scales, by which the variations of the temperatures
and corresponding pressures of steam or air, as the case may be, may be
shown and indicated, either or both of them, as desirable.
My improvements as applicable to safety valves, and as applicable to
pressure or temperature guages, may be employed either in combination or
otherwise.
My improvements are applicable to ordinary or saturated steam, to super-
heated steam, and to heated air.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Mash in the Great Seal Patent Office on the 9th
May 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
MASH, of Bowden, in the County of Chester, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of November, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-seventh year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said James Mash, Her special license that I, the James Mash, my
executors, administrators, and assigns, or such others as I, the said James
Mash, 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 APPLICABLE TO
SAFETY VALVES AND PRESSURE OR TEMPERATURE GAUGES," upon the condition,

page_text: amongst others, that I, the said James Mash, by an instrument in writing
under ny 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 James Mash, do hereby declare the
nature of the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following state-
ment, reference being had to the Sheet of Drawings hereunto annexed, and
to the letters and figures marked thereon (that is to say):-
:-
My improvements relate to apparatus applicable to the construction and
working of safety valves and pressure guages or temperature guages used and
employed in steam boilers, steam apparatus, and heated air apparatus. As
regards the application of my improvement to safety valves, it consists in
constructing and employing, in combination with any known descriptions of
safety valves, cylindrical or other formed vessels containing mercury, having
one or more parts of each expansible upon the application of heat, and
connected with the valves in such manner that upon increase of heat beyond
any predetermined temperature the valves are lifted from their seats and
steam liberated, the lifting of the valves being thus effected by the expansion
of the mercury contained in the cylinders or other vessels independently of
the loadings of the valves by weights, as they are usually used. The con-
nections between the mercury-containing cylinders or vessels and the safety
valves, or the mode of working, may be such that the valves can be opened
only by the expansion of the mercury, or may be such as to permit the
opening or raising the valves from their seats at any times by other means, as
by the pressure of steam or by hand, as is well known. The cylinders or
vessels containing the mercury are by preference placed in the boilers
themselves, or immediately upon them, but may be placed in other positions
where steam would have as free access as practicable to them, in order that
the temperature of the mercury may be affected with facility by any variations
of the temperature of the steam.
When I employ my improvements to pressure guages or temperature
uages, I connect the mercury-containing cylinders or vessels with pointers
r indexes upon convenient dials or scales, by which the variations of the
emperatures and the corresponding pressures of steam or air (as the case may
e) may be shown and indicated, either or both of them, as desirable.
My improvements as applicable to safety valves and as applicable to

page_text: pressure or temperature guages, may be employed either in combination or
otherwise.
My improvements are applicable to ordinary or saturated steam, to super-
heated steam, and to heated air.
The first part of my improvements relative to safety valves is illustrated
under one arrangement in the accompanying Drawings and the following
description.
Figure 1 is a sectional elevation of an ordinary lever safety valve, to which
my improvement is connected; A, the valve, which is mounted on its seat with
its weighted lever B in the usual manner. In this example the valve and
seat are mounted upon the pillow or support C, which contains the mercury-
containing cylinder or vessel D, this vessel, or a part of it, as D¹, is corrugated
so as to be capable of elongation or expansion and contraction in the direction
of its length; this vessel is entirely and wholly filled with mercury, the bottom
or lower end of the cylinder D rests on and is supported by the bottom of the
pillar C, and to the upper end of D¹ is the joint E, connecting it with the
compound levers F, F, the end F" of the lever F¹ is immediately under
the pin G in the stem A¹ of the safety valve, the flange C¹ of the pillar C is
for the purpose of securing it to the steam boiler or steam pipe or elsewhere
where it is to be used; the steam enters the interior of the pillar and surrounds
the mercury-containing cylinder through the apertures C", C"; the pin G,
is screwed through the stem A¹ of the safety valve, so as to adjust accurately
the relative position of the end of the pin G with the end F" of the end of the
compound levers, so that they may be in contact at any predetermined pressure
and temperature. The operation of the apparatus is thus:-It being adjusted
to any desired pressure, as fifty pounds per square inch, for example, that is,
that at this pressure the temperature due to it has so expanded the mercury
in the cylinder as to bring the end F" of the compound levers just into
contact with the pin G in the stem of the safety valve; upon increase of
pressure above the fifty pounds per square inch taking place the mercury
will be expanded, the containing cylinder of course elongated, and through
the compound levers the valve will be raised and lifted from its seat, allowing
steam to escape; thus whatever amount of weight may be upon the lever
of the valve though very considerably loading the valve above fifty pounds per
square inch (in this instance), the valve will be raised and the steam allowed
to escape when that pressure has been exceeded. The capacity of the mercury
vessel D, D', is such that the movement produced by the expansion of the
mercury shall be sufficient to lift the safety valve from its seat to the desired
height for the escape of steam.

page_text: Although I have shown and described that the movement produced by
the expansion of the mercury is transmitted to the safety valve through
compound levers, and which I generally prefer in practice, yet such may be
modified, as the top of the mercury vessel may act direct on the stem of the
safety valve without any lever or levers.
My improvement applicable to pressure or temperature guages is illus-
trated by Figure 2, which shows a sectional elevation of a guage; the
pillar C and mercury vessel D, D', are similar to what I have before described
with reference to my improved safety valve; the top of the mercury vessel is
connected by the parts shown in dotted lines behind the dial face H of the
guage; thus upon the top of the mercury vessel is attached the rod I, having
at its upper end a toothed rack working into a pinion J fast on the toothed
segment K, which latter geers into and works the pinion L, to which the
index hand N is attached; the face of the guage is or may be graduated to
denote pressures per square inch, and corresponding degrees of temperature,
either or both of them, as desired. The action of the guage is thus:-The
variation of the temperature of the steam causing the expansion or contraction
of the mercury will elongate or contract the length of the mercury vessel, and
this, acting through the connections to the dial hand, will indicate correctly
and with certainty the temperatures and pressures upon the dial face. Although
generally in practice I prefer to obtain the movement from the expansion and
contraction of the mercury by the corraginted form of the mercury vessel,
shown and described, other forms for such vesse may be used, which will
admit of variation of capacity.
Having described my improvements, I claim as my Invention,-
First, the application of mercury to safety valves, so as to obtain by its
expansion the lifting or raising such valves from their seats.
Second, the application of mercury to pressure or temperature guages so as
to indicate by its expansion and contraction variations of temperature and
corresponding pressures.
In witness whereof, I, the said James Mash, have hereunto set my
hand and seal, this Sixth day of May, in the year of our Lord One
Thousand night Lundand and sister foun
JAMES MASH. (LS.)