<3.Construction and Function>
3-8
IM 11R02A01-02E
5th Edition : Dec. 28, 2016-00
3.4.1
Burner Unit
The sample gas burns inside the burner unit and a thermocouple detects the burning temperature increase.
The air is introduced from the air inlet and divided to the primary, secondary and tertiary air. The primary and
secondary ones are for burning the sample gas and the tertiary is for diluting and stirring the exhaust gas. The
sample gas is mixed with the primary air (In case of the low calorie gas, the primary air is throttled), and burnt
completely by the secondary air. Then, the combustion temperature generates, and burnt gas is promptly
diluted and stirred by the tertiary air. Finally the gas is exhausted out from the top of the calorie detector. The
increased temperature is measured with the difference of the electromotive force between the cold junction
point (located at the air inlet) and the hot junction point (inside the mixed diluted exhaust gas). The heating
wire wound the burner tip is used for both ignition and preheating (when lower calorie gas is being used.)
Burner
tip
Heater wire
Lead wire
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Figure 3.9 Burner Tip Assembly
No. Name
1
Hot junction detect point
2
Cold junction detect point
3
Air divider
4
Secondary air throttle screw
5
Primary air throttle screw
6
Air inlet
7
Gas inlet
8
Connector
9
Burner tip assembly
10
Combustion pipe
11
Stream contact pipe
12
Measuring pipe
13
Reverse flow pipe
14
External pipe
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1
2
14
13
12
11
10
9
7
8
5
6
4
3
Figure 3.10 Burner Unit
