An Improvement in Thermometers.
Year: 1892

page_text: Date of Application, 17th May, 1892
Complete Specification Left, 17th Mar., 1893-Accepted, 22nd Apr., 1893
PROVISIONAL SPECIFICATION.
An Improvement in Thermometers.
I, FRANCIS SAMUEL TOMEY of 132, Park Road, Aston, Birmingham, Glass
Tube Manufacturer, do hereby declare the nature of this invention to be as
follows:
The divisions and figures which constitute the scale of a clinical or chemical
thermometer are at present marked externally on the front of the stem or tube
which is provided with a strip or backing of white enamel to facilitate reading the
scale. As the scale is exposed, its divisions and figures are very apt to be defaced
and obliterated by the cleaning or disinfecting which the instrument undergoes
after use and by the action of the acids into which it is dipped.
The object of my invention is to obviate this objection and to this end, it consists
in a thermometer whose stem or tube is provided with a coating which serves both
as a backing to enable the scale to be read and as a protector for the scale from
the injury above referred to.
In carrying out my invention, I prepare the thermometer in the ordinary manner
omitting however the incorporation with the stem of the enamel strip which is at
present drawn out therewith and, after producing the scale on the surface of the
stem by pointing in the usual way, I apply to that part of the stem or tube which
is so marked a fusible enamel flux, enamel paint, or equivalent material, and fuse
the same by heat or otherwise, taking care to prevent the flux or paint spreading
beyond the part to be covered and to avoid the melting of the tube.
This flux or
paint when hard forms a perfectly smooth coating or glaze which is impervious to
acids and at same time constitutes a backing by means of which the reading of the
scale is facilitated. To prevent the bursting of the thermometer during this
operation, I provide the upper end of the stem with a temporary chamber into
which the indicating fluid is free to pass, so that should the fluid become heated in
the bulb it can escape into the chamber for the time being in the same way as in
the process of contracting the bore of a clinical thermometer to prevent the
mercury running back after the temperature has been registered.
Dated thin 17th M
1000
By A. M. & Wm. Clark,
F. S. TOMEY,
53, Chancery Lane, London, Chartered Patent Agents.
COMPLETE SPECIFICATION.
An Improvement in Thermometers.
I, FRANCIS SAMUEL TOMEY of 132, Park Road, Aston, Birmingham, Glass
Tube Manufacturer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
When the divisions and figures which constitute the scale of a clinical chemical
or other thermometer are marked externally on the front of the stem of the
instrument in the ordinary way, they are very apt to be defaced and obliterated by
the frequent cleaning and disinfecting which a clinical thermometer undergoes
after use and by the action of the acids into which a chemical thermometer is
frequently dipped in the course of its service.
My invention has for its object to obviate this objection by providing the scale
with a protective covering which answers the double purpose of a protector for the
[D7

page_text: scale from the injury above referred to and of a backing to render the scale easily
legible.
In carrying out my invention, I manufacture the thermometer in the ordinary
manner, except that the white enamel stripe which is at present usually drawn out
and incorporated with the stem of the instrument is omitted. The graduation of the
instrument is effected by "pointing." and the divisions and figures of the scale are
etched on the surface of the stem in the usual way, but instead of etching them on
the front of the stem they are etched on the back and the position of the figures
reversed so as to read the right way when viewed from the front through the stem.
The graduations and figures so etched are then filled with ordinary black glass
paint or enamel as now used for marking thermometer-stems, after which I apply
to the rear side of the stem which has been so graduated a fusible enamel or
fusible glass paint, and fuse the same by heat, say, in a carefully-regulated oven,
or by the heat of a blow-pipe flame, taking care to prevent it spreading beyond the
part to be covered and to avoid overheating. This coating fuses at a comparatively
Now temperature and is composed of ordinary powdered white enamel or glass paint
mixed with the usual vehicle and is painted on in the usual manner of applying
such enamel or paint and when fused it forms on cooling a hard smooth white stripe
which resists acids (except of course hydro-fluoric) and at the same time
constitutes a backing by means of which the reading of the scale is facilitated.
To prevent the bursting of the bulb of the thermometer during the operation of
fusing on this enamel stripe I form at the upper end of the stem a temporary
chamber in communication with the bore and into which the indicating fluid is free
to expand for the time being. Such a temporary expansion chamber is well-known
to makers of clinical thermometers as being employed during the operation of
contracting the bore of the thermometer to prevent the mercury running back into
the bulb.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is―
A chemical clinical or other thermometer having the rear side of its stem
graduated and covered or backed by a protective stripe of fusible white glass paint
or enamel fused on as herein described.
Dated this 17th 018 OI Viaren 1035.
Dated GIS 17L01 03 01 VIRICH 1835.
F. S. TOMEY,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.