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● Combustion Monitoring Apparatus for Gas and Oil Burner
● Fire Alarm Apparatus
● Arson Watch Monitors
● Photoelectronic Counter
● Detection of Ultraviolet Ray Leakage
● Detection of Discharge Phenomenon
Parameter |
R13192 |
R9454 |
R2868 |
R9533 |
R244 |
R14388 |
R12257 |
Unit |
||
---|---|---|---|---|---|---|---|---|---|---|
Electrode material |
Ni |
Mo |
— |
|||||||
Spectral response range |
185 to 260 |
185 to 300 |
nm |
|||||||
Maximum |
Supply voltage (DC) |
420 |
500 |
400 |
400 |
575 |
420 |
425 |
V |
|
Average discharge current ① |
3 |
1 |
3 |
10 |
mA |
|||||
Peak current ② |
50 |
30 |
50 |
200 |
mA |
|||||
Operation ambient temperature |
-40 / +125 |
-40 / +125 |
-40 / +125 |
°C |
||||||
Characteristics |
Discharge starting voltage (DC) |
Max. |
260 |
360 |
280 |
280 |
440 |
260 |
240 |
V |
Discharge sustaining voltage (DC) |
Typ. |
185 |
300 |
240 |
230 |
330 |
185 |
170 |
V |
|
Sensitivity ③ |
Typ. |
15000 |
4000 |
5000 |
10000 |
480 |
10000 |
1200 |
min-1 ⑦ |
|
Background ④ |
Max. |
5 |
10 |
5 |
10 |
min-1 ⑦ |
||||
Estimated life ⑤ |
25000 |
10000 |
h |
|||||||
Recommended |
Supply voltage (DC) |
325 ± 25 |
400 ± 25 |
325 ± 25 |
350 ± 25 |
500 ± 50 |
325 ± 25 |
310 ± 25 |
V |
|
Average discharge current |
0.3 |
2 |
mA |
|||||||
Quenching time ⑥ |
Min. |
2 |
2 |
2 |
1 |
3 |
2 |
1 |
ms |
|
Weight |
5.2 |
1.5 |
1.5 |
2.5 |
3 |
5.3 |
5 |
g |
||
Suitable socket (Sold separately) |
E678-9C |
— |
— |
E678-8F |
— |
E678-9C |
— |
① Even at these current values, the electrodes are not consumed immediately, but the service life is noticeably reduced. Use the tube within the recommended current values.
② This is the maximum momentary current that can be handled if its full width at half maximum is less than 10 s.
③ These are representative values for a wavelength of 200 nm and a light input of 10 pW/cm2. Think of these values as relative sensitivity values. In actual use, the sensitivity will vary with the wavelength of the ultraviolet radiation and the drive circuitry employed.
④ Measured under room illuminations (approximately 500 lux) and recommended operating conditions. Note that these values will increase somewhat in outdoor uses due to the effect of sunlight.
⑤ This is the service life under the recommend operating conditions. Since high ambient temperatures will reduce the service life, when using the tube in a high-temperature application, such as a burner monitor, consider using air-cooling. The UVtron is covered by a warranty for a period of one year after delivery.
⑥ When configuring the tube with an external quenching circuit, use circuit constants so that the quenching time becomes longer than these values listed. When using a pulse driven circuit using CR, if the applied voltage is in the recommended range, the quenching time tq can be calculated with the following formula. (Refer to the diagram of the recommended operating circuit.)
tq 0.5 X C1 • R1
⑦ The RMS voltage when pulsating current is supplied.
The UVTRON is a bipolar tube with a structure similar to that of a phototube. Just as with phototubes, the UVTRON utilizes the photoelectric emission effect, but the inside of the UVTRON tube is filled with special a gas rather than be- ing a vacuum, so it operates as a discharge tube. Figure 2 shows its structure and a schematic diagram of operation. A voltage is applied across the anode and photocathode (cathode) which is only sensitive to ultraviolet light. When UV light passing through the UV glass (UVTRON bulb) strikes the cathode, photoelectrons (electrons) are emitted from the cathode surface due to the photoelectric emission effect. These photoelectrons are then drawn to the anode by the elec- trical field created by the supply voltage. If the supply voltage is low, the operation is the same as for a phototube and the current, i, is extremely weak. When the voltage is increased to strengthen the electrical field, the photoelectrons are accelerated so they collide with the gas molecules within the tube and ionize them. The electrons produced by ionization continue to collide with other gas molecules while causing ionization until they finally reach the anode. Meanwhile, the positive ions are accelerated towards the cathode and the resulting collisions with the cathode generate a great number of secondary electrons. As this cycle is repeated, a large current suddenly flows between the anode and cathode, creating an electrical discharge. This phenomenon is called gas multiplication and the voltage at which this discharge starts is called the discharge starting voltage Vl of the UVTRON. Once the electrical discharge has begun, the tube is filled with electrons and ions and the voltage that maintains the discharge drops to a low value. This value is called the discharge sustaining voltage Vs. Figure 3 shows this state. The UVTRON primarily operates in the glow discharge region, but in this region, since the discharge sustaining voltage Vs is lower than the discharge starting voltage Vl, the discharge will continue unless some means is employed to control the supply voltage.