JPS6326765Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a chemiluminescence analyzer, and more specifically, in a chemiluminescence analyzer that uses a photomultiplier tube to detect reaction light from a chemical reaction between ozone and a sample substance. A gas cooling pipe having an air inlet, an air outlet, and a waste water drain is installed in a cooling block provided for cooling the multiplier tube, so that the ozone generation source air flows into the air inlet of the gas cooling pipe. A chemiluminescence analyzer configured to further connect the air outlet of the gas cooling pipe with an ozone generator so that the ozone generator generates ozone for chemiluminescence from the ozone source air dehumidified in the gas cooling pipe. Regarding equipment. Furthermore, a divider resistor and a preamplifier are provided adjacent to the socket of the photomultiplier tube in the detector of the emission spectrometer, and these are moisture-proofed with silicone resin, and the magnetic shield plate of the photomultiplier tube is extended and surrounded.
This invention relates to a chemiluminescence spectrometer with improved electrical stability.

Photomultiplier tubes capable of measuring long wavelengths are widely used as detectors in chemiluminescence analyzers that apply the specific chemiluminescence reactions of chemical substances, but electronic coolers are often used to minimize thermal noise. It is attached. The chemiluminescence analyzer is also equipped with an electronic cooler dedicated to dehumidification to remove moisture, which is an obstacle to ozone generation, from the ozone source air necessary for chemiluminescence. Therefore, a total of two electronic coolers were used, which had the disadvantage that the analyzer became large.

Additionally, when detecting small amounts of light, the photomultiplier tube has a high output impedance and is susceptible to noise, but in conventional detectors, the output line of the photomultiplier tube, which is susceptible to this noise, is directly led out to the outside, and the electricity is It was not stable. In particular, when a large current flows through the electronic cooler, the photomultiplier tube, which is built into the electronic cooler, is significantly affected and has the disadvantage of making analysis unstable.

This idea eliminates the above drawbacks,
The object of the present invention is to provide a chemiluminescence spectrometer that is small in size, resistant to electrical disturbances, and has stable performance.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A detailed explanation will be given below based on an embodiment of the present invention shown in the drawings.

Figure 1 shows the analysis section of a chemiluminescent nitrogen oxide analyzer, and the right side of the figure is the photodetector section 1,
The left part is the chemiluminescent reaction part.

The photomultiplier tube 2 has its light-receiving surface facing the reactor 25 and is surrounded by a magnetic shield plate 10, a cooling block 3, and an electronic cooler 4. Heat from the electronic cooler 4 is radiated by a heat radiation fan 13 and a heat radiation fin 14 .

A gas cooling pipe 5 is provided within the cooling block 3 to dehumidify the ozone source air flowing into the ozone generator 26. That is, as shown in FIG. 2, the ozone source air is piped to flow into the air inlet 5a of the gas cooling pipe 5, and the air outlet 5b is connected to the ozone generator 26, so that the ozone source air is Moisture condenses while passing through the gas cooling pipe 5 and is dehumidified. The condensed water is discharged from the waste water drain 5c of the gas cooling pipe (third
figure).

A divider resistor 7 and a high input impedance, low output impedance preamplifier 8 are provided adjacent to the socket 6 of the photomultiplier tube 2. The circuit thus constructed is like the example shown in FIG. It is the electronic cooler 4 that covers the pudding amplifier etc. with silicone resin 9.
This is to prevent moisture from condensing on the circuit components and causing insulation defects when the circuit components are cooled.

The magnetic shield plate 10 is a cylinder made of a magnetically resistant material such as permalloy, and has conventionally been provided around the photomultiplier tube 2, but in the present invention, this is extended to include a socket 6, a divider resistor 7, and a printer. It is configured to surround all the amplifiers 8.

Reference numerals 11 and 12 are an O-ring and a cap, respectively, for keeping the measuring circuit portion airtight.

A gas containing nitrogen oxide, which is a sample gas, is introduced into the reactor 25 from the sample inlet 15 of the chemical reaction section. At the same time, ozone is introduced from the ozone inlet 16, and the two react to produce chemiluminescence, which is then discharged from the outlet 17. The reaction light emitted at this time is the motor 2
The signal is picked up by the rotating sector 23, converted into an alternating current signal, and incident on the detector 1. The reactor 25 is housed in an aluminum case 24 equipped with a band heater 20, and is maintained at about 50° C. by a humidity sensor 21.

Now, as described above, the chemiluminescence analyzer of the present invention is equipped with a gas cooling pipe 5 in the cooling block 3 that cools the photomultiplier tube 2, and cools the ozone source air (to about 5°C). Since dehumidification can be performed, an electronic cooler for dehumidifying the ozone source air, which was necessary in the past, is no longer necessary. Therefore, the entire analyzer can be configured to be compact. Furthermore, since there may be cases where it is desired to dehumidify the sample gas, it is desirable to provide a gas cooling pipe (not shown) for the sample gas. In this case, there is an effect that an electronic cooler for dehumidifying the sample gas becomes unnecessary.

Next, the chemiluminescence analyzer of the present invention is equipped with a divider resistor 7 and a preamplifier 8 adjacent to the socket 6 of the photomultiplier tube 2.
The high impedance output line 27 of is extremely short. And the line drawn out is
Preamplifier 9 low output impedance line 2
8, so it is stable against external electrical influences. In addition, the socket 6, divider resistor 7, and preamplifier 8 are cooled to approximately 5°C and kept at a constant temperature, just like the photomultiplier tube 2, so thermal noise is reduced and fluctuations in circuit characteristics due to temperature changes can be suppressed. can. These are also sealed with silicone resin to prevent insulation failure due to moisture condensing during cooling. Furthermore, since the magnetic shield plate 10 completely covers everything from the photomultiplier tube 2 to the preamplifier 8, the influence of external magnetic fields, especially the magnetic field caused by the large current flowing through the electronic cooler 4, is easily cut off. In addition to lowering the impedance of the output line, it is also less susceptible to electrical disturbances, making stable measurements possible.

[Brief explanation of the drawing]

Figure 1 is an explanatory cross-sectional view of the analysis section of the chemiluminescence analyzer of the present invention, Figure 2 is an explanatory diagram of the flow path of ozone source air, Figure 3 is an enlarged view of the gas cooling tube, and Figure 4 is photoelectron multiplication. It is a diagram showing the electric circuit of the tube, divider resistor and preamplifier. 1... Photodetection section, 2... Photomultiplier tube, 3...
Cooling block, 4... Electronic cooler, 5...
Gas cooling pipe, 6... Socket, 7... Divider resistor, 8... Preamplifier, 9... Silicone resin, 1
0... Magnetic shield plate, 18... Window glass, 19
...O-ring.

Claims (1)

[Scope of utility model registration request] In a chemiluminescence analyzer that uses a photomultiplier tube to detect reaction light from a chemical reaction between ozone and a sample substance, an air inlet and an air outlet are installed in the cooling block installed to cool the photomultiplier tube. and a gas cooling pipe equipped with a wastewater drain, piping is provided so that the ozone generation source air flows into the air inlet of the gas cooling pipe, and the air outlet of the gas cooling pipe is connected to the ozone generator. The ozone generator is configured to generate ozone for chemiluminescence from the ozone source air that is dehumidified in the process, and a divider resistor is installed adjacent to the socket of the photomultiplier tube, and a preamplifier with high input impedance and low output impedance is installed. A chemiluminescence analyzer characterized in that the socket, the divider resistor, and the preamplifier are dehumidified with silicone resin, and are surrounded by an extension of the magnetic shield plate of the photomultiplier tube.