Improvements in and relating to Air-heaters.
Year: 1899

page_text: Date of Application, 23rd May, 1899-Accepted, 1st July, 1899
COMPLETE SPECIFICATION.
Improvements in and relating to Air-heaters.
We, EDWIN RUTHVEN WATERMAN, D.D.S., and ROBERT REID MORISON,
Electrician, both of No. 1833, Polk Street, in the City and County of San
Francisco, State of California, U.S.A., do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
This invention relates to an apparatus which is especially designed for heating
air. It consists essentially of a cylindrical casing, a nozzle removably connected
therewith, a tube and coil passing into said casing and connecting with the
nozzle, an electrical heater surrounding said tube, and a handle and means for
applying or cutting off an electrical current whereby the air passing through the
tube is heated to any desired degree.
In dental work it is necessary to apply a current of air to dry the teeth or
cavities therein, and when the teeth are extremely sensitive, a current of cold
air causes the patient great distress. It is the object of this device to provide a
convenient heater in conjunction with a nozzle through which a current of warm
air may be directed into the cavity or upon the part where it is desired to use
it, and to so temper the heat of this air current as to prevent its unduly dis-
tressing the patient. It is also used for making sensitive teeth absorb medicine,
thus obtunding sensitive dentine.
In carrying out the invention, and referring to the accompanying drawing,
we have shewn an exterior casing A open at the rear and having a removable
insulated handle portion B connected therewith by a screw or otherwise.
The front end of the casing A has a central opening of sufficient diameter to
receive the nozzle C. This nozzle has an expanded base, as shewn at C', the
base being of sufficient diameter to approximately fit the interior of the cylinder
chamber A, and when the nozzle is inserted through the opening, it is put into
place from the rear, the part C₁ fitting up against the inside of the closed end
as shewn.
D is a pipe which is preferably made of copper and is connected at one end with
a flexible hose or other source of air supply E.
Air may be forced through this by a hand compression bulb, or by any suit-
able means if power is available to furnish a desired current.
This tube D'extends through the centre of the chamber A, and is preferably
bent to form one or more turns as at D¹, within the chamber A.
Surrounding this tube and coil is an electrical heating device F of any suit-
able description. As here shown it consists of a coil of resistant wire through
which an electrical current may be passed and the wire heated by said current,
o that the heat passing through the wire will be imparted to the inner tube and
oil D¹.
G is an insulating lining to the chamber A which surrounds the heating coil
nd insulates it from metallic contact with the casing.
Upon the side of the handle extension B is fixed a spring-pressed contact
iece as shown at H. This contact piece is placed intermediate between the wires
f the heating coil and the electrical supply and is normally onen

page_text: It is closed by pressure of the hand so that the electrical current will pass
through the coil and the air conducting tube DD' will be sufficiently heated so
that the air passing there-through, will be delivered through said tube into the
nozzle C and thence directed to the point where it is to be used.
The degree to which the air is heated is easily controlled by means of the con-
tact device H, and the apparatus is always in readiness for use whenever needed.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1st. An air heater comprising an outer casing, a central air conducting pipe
and coil, an electrical heater surrounding said air pipe, a nozzle connecting with
the air pipe and case, and a connection through which air is delivered through
the heating pipe.
2nd. An air heater for dental and other purposes, consisting of an exterior
cylinder, an interior air-conducting heating pipe and coil, a nozzle connecting
with the discharge end of the pipe, an electrical heater surrounding the pipe and
an insulating therefor, wires connecting the said heater with the source of elec-
trical supply and a contact making and breaking device interposed in the elec-
trical circuit.
3rd.—An air heating device consisting of an exterior casing having an open
rear and a central opening formed at the front end, a nozzle slidably fitting
through said opening having an enlarged base flange fitting within the interior
of the casing, an air conducting tube and coil extending through the casing
and connecting with the nozzle, a surrounding insulated electrical heater whereby
the coil and passing air are heated, an insulating handle with which the casing
is connected, wires connecting the heater with a source of electrical supply, and
interposed contacts whereby a normally open circuit is maintained, said circuit
being closed by pressure upon the contact device to control the action of the
heater.
Daten this Zord day of May 1899.
For the Applicants,
GEDGE & FEENY,
Chartered Patent Agents, 60, Queen Victoria Street, London, E.C.