Improvements in Maximum Thermometers.
Year: 1898

page_text: Date of Application, 31st Jan., 1898
Complete Specification Left, 31st Oct., 1898-Accepted, 3rd Dec.,
1898
PROVISIONAL SPECIFICATION.
Improvements in Maximum Thermometers.
GEORGE WILLIAM SIMPSON, 19, Whiskin Street, Clerkenwell, London, E.C.,
do hereby declare the nature of this invention. to be as follows:-
Clinical and other kinds of maximum thermometers having very small bores
the person using these thermometers experiences great difficulty in adjusting
the mercury or other indicating fluid having to use a considerable amount of
violence in shaking the indicating fluid to below the scale marks or divisions.
My invention has for its object to provide such thermometers with an index
or indicating column of mercury or other fluid formed by slightly expanding the
bore above the usual constriction as is already done in many kinds of maximum
thermometers.
I propose to place in this enlargement of the bore a sufficient quantity of air
to separate the mercury or other fluid contained therein the usual constriction
may be retained or not as required the air is so placed in the enlargement or
chamber that no matter what the maximum temperature may be the air will
not enter the small indicating bore the lower part of the mercury forming the
index being always in the chamber but separated from the remainder of the
indicating fluid by the portion of air between by this method of making the
thermometers the air in the enlarged bore being elastic forms a spring which
when the index portion is shaken down presses the mercury through the con-
stricton below the chamber by this means the adjustment of the thermometer
is greatley facilitated and much time and danger of breaking is avoided an advan-
tage I claim is that by having an elongated index as described instead of the
short index usually used which must always be kept in the small indicating:
bore. By my method the mercury being when adjusted entirely clear of the small
indicating bore. After using, the readjustment of the thermometer is made
by the person using it by shaking the index down upon the air in the enlargment
in the tube it will he apparent that the indicating bore being so small a very
slight movement of the fluid in the enlarged part of the tube will have the
desired effect of clearing the indicating bore.
1000

page_text: same is to be performed to be particularly described and ascertained in and by
the following statement:-
In clinical and other maximum thermometers having very small bores, it is
well known that great difficulty is experienced in adjusting the mercury or
other indicating fluid, the thermometer having to be shaken with considerable
violence in order to cause the indicating column to descend below the scale marks
or divisions.
Now my invention refers to means for facilitating the adjustment of the
indicating column and thereby saving loss of time and lessening the chances of
breakage.
In order that my invention may be readily understood, I will describe same
with reference to the accompanying drawings whereon Fig. 1 shews a diagram-
matic elevation of a thermometer constructed according to my said invention and
Fig. 2 is a similar view shewing a slightly modified construction.
Referring to the drawing, A is the body of the thermometer, B the bulb and C
the bore which is of small size as is usual in this type of thermometer; D is the
constriction. According to my invention, I expand the bore either immediately
above the constriction D, as will be seen by reference to Fig. 1, or I expand the
bore at a short distance above the constriction 1) as shewn at Fig. 2, such expan-
sion of the bore forming a chamber E. In this chamber E I place a sufficient
quantity of air to separate the mercury or other indicating fluid, which latter is
illustrated in black in the drawing, and the separating air by the white space
marked F.
The air chamber E is of such a proportional size and the air space is so placed
that no matter what the maximum temperature may be, the air will not enter
the small indicating bore, the lower part of the mercury G forming the index,
being always in the chamber E but separated from the remainder of the indicat-
ing fluid H by the portion of air F. By this arrangement and construction of
thermometer, the air F in the enlargement or chamber E of the bore being
elastic, forms as it were a spring, which when the index portion of the column G
is shaken down, presses the mercury through the constriction 1) below the cham-
ber E and by this means the adjustment of the thermometer is greatly facilitated
and much time is saved and danger of breaking avoided. By having an elon-
gated index instead of the short index usually used, which latter must always
be kept in the small indicating bore, in my arrangement the mercury is when
adjusted entirely clear of the small indicating bore.
After using, the readjustment of the thermometer is made by the person using
it shaking the index down upon the air in the enlargement in the tube and it
will be apparent that the indicating bore being so small a very slight movement
of the fluid in the enlarged part of the tube will have the desired effect of clearing
the indicating bore.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is:
an
The arrangement or construction of clinical or other maximum thermometer,
having a chamber above the constriction, such chamber being formed as
enlargement of the bore, and caused to contain a stratum of air, substantially as
and for the purposes described with reference to the accompanying drawings.
Dated this 31st day of
1000
BREWER & SON,
London and Leeds, Agents for the Applicant.
BREWER & SON,
London and Leeds, Agents for the Applicant.