IMPROVED INCUBATOR
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by the said Thomas Christy at the
Office of the Commissioners of Patents on the 10th October 1882.
THOMAS CHRISTY of 155 Fenchurch Street in the City of London Merchant
"IMPROVED INCUBATOR"
My improved incubator consists of an iron water tank acted upon and kept hot
by a small boiler, connected with it by two copper pipes.
By the lower of these pipes water passes from the tank into the Boiler. Whence
after being subjected to the heat from a lamp below it passes back again by the
upper pipe into the main tank and radiates its heat downwards upon the eggs,
kept in a drawer below it.
To ensure the necessary regularity of temperature in this Egg drawer, the
bottom of the water tank converges upwards towards the centre and is there pierced
by an air shaft, carried up through the tank and the packing, and wooden casing
enclosing the. Tank-In the air chamber, between the tank and the egg-drawer, is
fitted a thermostatic band which is acted upon by the heat, and controls (through a
lever arrangement connected with it by a rod passed down a small pipe inserted
through the water tank), a valve fitted upon the top of the air shaft-The effect of
this is twofold, It first insures a regular temperature above the eggs, and its
second effect is to produce a perfect system of ventilation over the eggs-In the
casing of the incubator are bored air-holes, and when the valve is open, the air
enters at the bottom of the Incubator (and in a much less degree at the sides or
back and front) and is evenly distributed throughout the egg drawer.
The Lamp used for heating the circulating boiler is fitted under a metal chimney
which encircles closely the boiler.-At the bottom of the chimney is fitted a broad
convex collar or flange, pierced so as just to allow space for the flame but fashioned
so as to prevent as much air as possible from passing up―This collar or flange
also extends beyond the chimney forming a flange outside it.

page_text: Both the lamp at side or back and the valve and lever on top of the Incubator
are protected by screens or covers-A Thermometer is made to slide in and out of
the egg drawer and another thermometer serves as an Index to the heat of the
water in the main tank.
The necessary moisture for the eggs is provided by a narrow water vessel which 5
fits round and underneath the egg. drawer-The space between the sides of this
water vessel is covered by coarse canvas, the ends dipping into the water all
round.
By capillary attraction the canvas is thus képt damp and the incoming air as
it passes through the wet canvas absorbs the necessary degree of moisture for the 1
requirements of the eggs.
A scale at the aperture shows the distance the valve is open and enables the
operator to set the regulating valve.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Christy in the Great Seal Patent Office on the 9th April
1883.
THOMAS CHRISTY of 185 Fenchurch Street in the City of London Merchant
"IMPROVED INCUBATOR"
My improved Incubator consists of an iron water tank inclosed in non-conducting
materials, the water in such tank being kept hot by a small boiler connected
with it and heated by a lamp-The connection between the boiler and the tank
is formed by means of two copper pipes By the lower of these pipes water passes
from the tank into the boiler whence, after being subjected to the heat from the
lamp below, it passes back again by the upper pipe into the tank and radiates its
heat downwards upon the eggs kept in a drawer below it-To ensure the necessary
regularity of temperature in this egg drawer the bottom of the water tank
converges upwards towards the centre and is there pierced by an air shaft carried
up through the tank; and the packing and wooden casing enclosing the tank. In
the air-chamber, between the tank and the egg drawer, is fitted a thermostatic band
which is acted upon by the heat, and controls (through a lever arrangement con-
nected with it by a rod passed down a small pipe inserted through the water tank)
a valve fitted upon the top of the air-shaft. The effect of this is two-fold. It first
ensures a regular temperature above the eggs, for, as the heat rises the higher
temperature causes the metal band to draw down the rod connected with the lever
and this raises the valve allowing more air to escape and thereby reducing the
temperature should the heat on the contrary get below the desired. point, the
opposite result is brought about, the metal band gradually lowers the valve and
closes the air shaft. When closed the temperature again immediately begins to
rise.
Its second effect is to produce a perfect system of ventilation over the eggs. In
the casing of the Incubator air holes are, bored in the bottom and also in the
wooden false bottom (but such holes are not in a direct line with each other) and
other holes are also made at the sides, or back and front, as close as may be under
the level or bottom of the water tank and when the valve is open the air enters at
the bottom of the Incubator (and in a much less degree at the sides or back and
front) and is evenly distributed throughout the egg drawer.
In working, a constant current of fresh air is always passing through the
Incubator except when the valve at the top is quite closed.
The bottom of the tank is dished, cambered or coned in order to assist in
equalizing the temperature and to conduct the heated air to the air shaft
The Lamp used for heating the circulating boiler is fitted under a metal chimney
which encircles the boiler-At the bottom of the chimney is fitted a broad convex
collar or flange pierced so as just to allow space for the flame, but fashioned so as
to prevent any surplus of air from passing up-This collar or flange also extends
beyond the chimney forming a frustum of a cone outside it.
Both the lamp at the side or back and the valve and lever on the top of the
incubator are protected by screens or covers A Thermometer is made to slide in
and out of the egg drawer or is otherwise fitted in any obvious way for showing the
temperature therein and another Thermometer serves as an Index to the heat of
the water in the main tank.
The necessary moisture for the eggs is provided by a narrow water vessel or
rectangular trough which fits round and underneath the egg drawer-The trough
is filled with water and is covered by coarse canvas the edges of which dip into the

page_text: water all round By capillary attraction the canvas is thus kept damp and the
incoming air as it passes through the wet canvas absorbs the necessary degree of
moisture for the requirements of the eggs. A scale is fitted which shews the
distance the valve is open and enables the operator to set the regulating valve.
And in order that my said invention may be clearly understood reference is
hereby made to the accompanying drawings, in which similar letters of reference
indicate corresponding parts in both figures.
Fig 1 is an external view, in perspective, of my said invention and Fig: 2 is a
sectional elevation thereof.
a is a valve capable of closing the tube b which tube forms the air shaft When b
is closed by a the internal temperature is raised and when bis open na shewn in
Fig: 2 the emission of air reduces the temperature-c is a rod passing downwards
through a small tube and connected with the thermostatic band g-This band is
constructed to act by the unequal expansion of two metals such as iron and zinc
held in contact A rise of temperature causes the band g to descend and draw the
rod c downwards, and the regulating nut d causes the valve a to rise-As the
temperature again falls the opposite effect takes place, and the valve a is gradually
lowered upon the air-shaft b. By means of the nut d the regulation of the tem-
perature can be ensured-wis the water tank connected with the boiler by the
circulating pipes The bottom of the tank is dished, cambered, or coned as
shewn The boiler h is made conical, and its diameter is nearly equal to that of the
chimney leaving just space enough for the products of combustion to pass. up
the chimney The lower end of the chimney is fitted with a collar a to direct the
air to the flame of the lamp and prevent any surplus air from passing is the
lamp which stands upon the wooden slide pand which is capable of adjustment;
i is a screen for the lamp and a is a wire screen for the valve and lever (shewn
raised in the figures). is a tube for filling the tank with water; 1, are the holes
for the entrance of air;t is the rectangular trough or evaporating pan, filled with
water and being covered with a piece of coarse canvas the edges of which dip
into the trough, the entering air being thereby kept moist- is the egg tester
which is a receptacle opposite to the light for examining the eggs-w is the packing
of nonconducting material to prevent loss of beat, m is the front of the drawer
which is capable of sliding in and out:-u is a diaphragm fitted to the tank u to
ensure the circulation of the water.
8
Having thus particularly described the nature of my said Invention and the
matter in which the same is to be performed I clain :-
1. The general construction combination and arrangement of parts respectively
together forming my improved Thermostatic Incubator substantially as herein-
before described and shewn on the drawings or any mere modification thereof
In witness whereof 1 the said Thomas Christy have hereurfto set my hand
and seal this ninth day of April in the year of our Lord one thousand
eight hundred and eighty three.
THO CHRISTY (JSP)