IMPROVEMENTS IN INCUBATORS OR APPARATUS FOR HATCHING EGGS BY ARTIFICIAL MEANS, PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER PURPOSES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Walter Muir at the Office of the
Cominissioners of Patents on the 11th January 1883.
WALTER MUIR, of Thornliebank, in the County of Renfrew, North-Britain,
"IMPROVEMENTS IN INCUBATORS OR APPARATUS FOR HATCHING EGGS BY
ARTIFICIAL MEANS, PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER
PURPOSES,"
This Invention which relates to improvements in the construction of incubators
or apparatus for hatching eggs by artificial means, has special reference to improved
arrangements of automatic heat regulating and ventilating appliances fitted in
connection therewith, whereby a regular or uniform temperaturo may be maintained
within the incubator, and whereby the degree of heat may be varied to suit the
kind of eggs to be hatched. The Invention also comprises improvements in the
fitting of the egg drawers, and in minor details of the apparatus; and the improve-
ments in the heat regulating and ventilating devices are also applicable to other
purposes, as for stoves and green-houses, and in general whero it is desirable that
a uniform or approximately uniform temperature should be maintained.
As ordinarily constructed, artificial incubators consist of a large wooden box or
frame, protected by a jacket filled with wool, hair, saw-dust, or other non-conductor,
within which box is enclosed a tank or cistern containing hot water, and a drawer
or drawers fitted below to contain the eggs which are kept warm by the heat
radiated from the hot water tank or cistern above. The necessary heat is
maintained either by periodically withdrawing portion of the water from the tank
as it cools, and re-filling it with hot water, or by the heat from a lamp or burner.
The temperature of the water in the tank or cistern varies considerably, and the
eggs are therefore subject to variations of temperature which is injurious to the
development of the germ in the egg.
In Incubators constructed according to the present improvements, the water in
the tank or vessel is heated, and the heat is maintained by a lamp or burner fitted
below a small circulating boiler or heating vessel connected to the main tank or
cistern by water circulating pipes fitted at the top and bottom of the tank. A
funnel or outlet flue for the products of combustion is carried from the combustion
TDA71

page_text: chamber of the heating vessel up through that vessel and horizontally or in an
inclined direction through the main water tank and out at the opposite side where
it is bent upwards. The water in the tank is thus also heated by the products of
combustion passing through the flue. Over the outlet end of the flue or funnel is
suspended a flat plate which serves as a damper. This damper is hung from a
-beam lever or balance carried over the box or frame and provided with a movable
weight; and at the other end of the lever or balanco is hung a similar damper or
valve plate which fits over a ventilating air tube extending from the drawers or
egg chamber to the top of the box. A slight extent of play is left between the
valves or dampers, and the respective tubes they cover, and when the temperature
of the water within the tank remains uniform, a steady flow of air is allowed to
pass by the ventilating air tube from the egg chamber, while the products of
combustion of the lamp or burner also pass freely by the funnel or outlet flue. As
a means of automatically regulating the temperature of the water within the tank,
and of allowing more or less ventilation of the egg chamber, the balance is caused
to tilt when a change of temperature occurs, and partially or entirely open or close
the smoko outlet while closing or opening the air outlet. For this purpose, a small
bottle or vessel containing mercury is suspended from the outer end of the beam
lever or balance carrying the valves or dampers, and into this mercury is caused to
dip, a bent tube or syphon pipe also containing mercury. This bent tubo is
connected to a tube in communication with a series of close metal tubes passing
into the egg chamber or chambers below the water tank, and which tubes are filled
with water, spirit, glycerine, or a mixture of spirit and glycerine, or with other
liquid or fluid. The heat of the water within the tank or cistern is communicated
to the liquid or fluid within these tubes by radiation, and the expansion or
contraction of such liquid or fluid due to variations of temperature of the ogg
chamber causes the mercury to be forced out or drawn into the syphon or bent
tube which dips into the vessel of mercury, and correspondingly increases or lessens
the quantity of mercury in this vessel. The variation in weight of the vessel thus
brought about, causes the balance or beam lever to oscillate on its centro, and open
or close the outlet flue according as the temperature is too low or too high, the air
outlet being closed or opened to a corresponding extent.
When the outlet flue is partially closed, the products of combustion being kept
back, not only cause less beat to be radiated froin the flue to the tank through which
it passes, but also reduces the amount of heat communicated to the boiler or heating
vessel by the lamp or burner.
In the improved incubators, the drawers containing the eggs to be hatched are
provided with shallow moisture pans over which the usual perforated or woven
wire egg trays are fitted. The moisture pans are however so fitted that they can
be raised or lowered individually by means of a screw or screws from the outside,
and the eggs in one tray may thus be brought closer to or withdrawn from the
source of heat above, so that small eggs may be hatched in one drawer, while
larger eggs are being hatched in the adjacent drawer. For this purpose the
moisture pans are connected at an angle by parallel links, to a sliding bottom or
sliding bars fitted in the bottom of cach drawer, and provided with nuts into which
the screws fit; and small rollers or castors are fitted in front of the pans to bear on
the inside of the drawer. When the screw or screws outside are turned to bring
the sliding bars forward, the pan above being prevented from moving forward also,
is raised upwards by the angled connecting links which act as in a parallel ruler.
This arrangement is also advantageous when only a single drawer is fitted in the
incubator box. The front of the drawer is fitted with a transparent pane as usual
to admit of inspection of the eggs and of a thermometer which is placed inside.
The bottom of the box or casing of the incubator is perforated or pierced with a
large number of small holes for the admission of air to ventilate the egg chamber,
and short tubes are passed through the moisture pans, so that the air may pass
through these pans and absorb moisture.
By a further improvement an oval holo is cut in the combustion chamber of the

page_text: lamp or burner, and a guard or holder is fitted outside into which the egg may be
placed opposite the hole to be examined by the light of the lamp or burner.
The improved appliances are also applicable for ventilating and regulating. the.
temperature of hot houses or conservatories, drying chambers, and other buildings
or apartments in which it is desirable to maintain an approximately uniform
temperature.
When applied in such cases, one end of the tilting or oscillating lever is connected
as before described to a valve or damper to open or close the outlet flue for the
products of combustion from the source of heat, which may be a furnace, and the
opposite end of the lever is connected through cords or levers to doors or windows
which are opened or closed by the motion of the lever to admit cold air, or permit
of the escape of heated air, or both.