IMPROVEMENTS IN APPARATUS FOR AUTOMATIC VENTILATION, AND THE INDICATION OF MINUTE VARIATIONS OF TEMPERATURE
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Thomas Brown Jordan and Thomas
Rowland Jordan at the Office of the Commissioners of Patents on the 3rd
December 1879.
THOMAS BROWN JORDAN, and THOMAS ROWLAND JORDAN, of Adelaide Chambers,
Gracechurch Street, in the City of London, Engineers. "IMPROVEMENTS IN
APPARATUS FOR AUTOMATIC VENTILATION, AND THE INDICATION OF MINUTE
VARIATIONS OF TEMPERATURE."
Our Invention relates to the construction and adaptation of an improved auto-
matic indicator of variable temperatures, which may be applied to the automatic
opening or closing of ventilating apertures, or to the regulation of the supply of
gas where used for heating purposes, or to act as a simple indicator of temperature,
and as an alarm in case of excessive overheating by fire or other accident.
This apparatus consists of a perfectly air tight vessel formed of very thin sheet
metal, and of such shape that no alteration of capacity can occur in ordinary
usage. This vessel is encircled by a tube also formed, by preference, of thin metal,
which is bent into a circle, but its ends do not quite meet. One end is in air tight
connection with the hollow vessel previously described, and the other is open to
the atmosphere. The whole is accurately balanced between centres, so that the
circular tube can revolve in a vertical plane. A portion of mercury, more or less,
according to the size of the ventilator is poured into the open end of the circular
tube, which is uppermost, so that the mercury now collects in the lower portion
of the circle on account of its gravity and fluid condition.
If now the atmosphere surrounding the hollow chamber before referred to (which
may be filled with air, alcohol, or other sensitive gaseous or liquid body), be raised
in temperature, the contents of the hollow chamber will expand, and thus press
upon one surface of the mercury in the encircling tube. This mercury is thus
forced nearer to the open end of the tube, and as the whole was before accurately
balanced, and is now free to revolve, it will turn about its centre in obedience to
new position of the centre of gravity of the mercury.
The above instrument may be made of any size, weight, or power, and may be
supplied with means of adjustment, so that it can be regulated to close or open the
ventilator at any given temperature, and thus regulate the temperature of any
chamber with great accuracy by checking or admitting the heating or cooling
currents of air.

page_text: As a safe guard against fire, gas explosions, or the rupture of vessels containing
inflammable materials, the apparatus may be so fitted as to strike off an alarm
detent under any sudden accession of temperature, or by any other mechanical
means give audible notice of the accident. Steam from any steam boiler on the
premises may by admitted by this detent or other mechanical appliances to
extinguish the fire, or any fire extinguishing fluid may be released from a reservoir.
Any such extreme accession of temperature will also serve to completely close
the ventilator and stop the draught, and thereby check any combustion in the
chamber.
An incompressible liquid, such as alcohol, should be used in the closed sensitive
vessel to accurately indicate minute variations of temperature, as the action of a
gas would be affected by barometrical changes.
The tube containing the mercury, may, if required, be lined with any suitable
material to prevent amalgamation.