Incubator Structure An overview of the mechanics of incubators

supplied by Research Instruments in the UK & Ireland

With thanks to Astec Japan

Co- author Rob Watkins Research Instruments

Incubation Area

Water Jacket

Heater

Styrene foam

Glass Wool

Water Jacket

Heater

Temperature Sensor A

Sensor A maintains the water of a water jacket at fixed temperature.

Temperature Sensor B

Sensor B is a temperature sensor for displaying the temperature of the incubation area.

R1 R2

Dry air

Air

THERMISTOR

It is the structure measured by the difference of the thermal conductivity of damp air and dry air. Current is passed so that the self-exothermic temperature of each THREMISTOR might become about 200 degrees. The method of converting the difference of the resistance ingredient by temperature change of the THERMISTOR itself into humidity by the heat conduction by steam is measured. It turns out that it is influenced by other gases, and only the error ingredient of the output to CO2 gas is detected. The output of this absolute humidity converts into CO2 gas concentration, and is measured and used as the reference.

Hole

0.5 1.0 1.5 2.0 2.5

5

0.5

10

0

-5

-10

hum

idit

y ab

solu

tely

(g/

m )3

Concentration (%)

CCl2F2CO2

CH4H2

Influence of mixing of gas

The principle of THERMISTOR formula CO2 sensor

Requires fixed temperature

Requires fixed humidity

☞

☞

IR light source IR Detector

CO2IR light If the infrared rays from a light source go into a sample cell, specific wavelength will be absorbed by CO2 gas in a cell. The amount of absorption increases, so that the concentration of CO2 is high, and the amount of penetrations on the Detector decreases. The result is a method which measures the

It will be absorbed if there is much CO2.

IR SENSOR Graphical Representation

IR SENSOR Graphical Representation

Thermistors Infrared (IR) formula

Readily available easy to

producre

Influenced by humidity

Influenced by temperature

Cheap to end user

Readily available but costly to

produce

Not influenced by humidity

Not influenced by temperature

More Expensive

Incubation area

Water jacket (for temperature control)

(for a temperature display)THERMISTOR A

THERMISTOR B

Two temperature sensors are used.By keeping the water temperature of a water jacket constant with THERMISTOR B, it uses that the temperature and turns into fixed temperature within the culture space. THERMISTOR A is used in order to display the temperature in area but this is maintained by probe B.

A THERMISTOR is a heat semiconductor from which resistance changes in temperature are monitored. Is was not built for that initial purpose. It is the structure that allows us to detect temperature by passing and investigating the resultant resistance.

The THERMISTOR is adopted as a temperature sensor.

The characteristic of temperature-resistance of a THERMISTOR

When temperature changes, it has the characteristic that internal resistance changes.