JP4750580B2 - Method and apparatus for measuring ozone concentration - Google Patents

Description

  This invention is located in a place where ozone gas leak monitoring is required in advanced treatment in water purification plants that utilize ozone at high concentrations, cleaning in semiconductor factories, film formation processes, etc. The invention relates to a simple and inexpensive ozone concentration measuring apparatus that emits an alarm when the ozone concentration in the place reaches a specified value or more. The present invention also relates to a simple and inexpensive ozone concentration measuring device used for monitoring the ozone concentration for controlling the indoor environment such as fumigation for the purpose of sterilizing and deodorizing air and equipment in food factories.

Ozone has an absorption spectrum (Hartley band) having a peak near 254 nm in the ultraviolet region, and the low-pressure mercury lamp has a strong spectrum at 253.7 nm. Therefore, a sample that does not contain ozone (zero gas) first flows into the measurement cell, and the amount of ultraviolet light transmission Lo at this time is measured. Then, the sample gas flows into the measurement cell, and similarly the amount of ultraviolet light transmission Lx is measured. The ozone concentration C was obtained from the following equation.
[Formula 1] C = Klog Lo / Lx K: proportionality constant

In such an ultraviolet absorption type ozone concentration measuring device, zero gas from the zero gas generator and sample gas containing ozone are alternately sent into the measurement cell, and each ultraviolet ray transmission amount is sent to a calculator to obtain the ozone concentration. Therefore, precise ozone gas concentration detection is possible, but a switching valve device for alternately feeding the sample gas and the reference cell into the measurement cell, a pump device for forcibly discharging the gas after measurement, etc. I needed it. The following non-patent literature is presented as an example of such an ozone concentration measuring apparatus.
High-precision ozone monitor EG-2001 series catalog made by Ebara Jitsugyo Co., Ltd. (distributed January 2005)

  Such a conventional ozone concentration measuring apparatus includes a pump, a switching valve, and the like, so that the cell can be replaced quickly because the cell diameter is small. However, the entire apparatus is complicated and expensive. Since ozone concentration measurement needs to be sampled at as many locations as possible, it is desirable to arrange as many ozone concentration measuring devices as possible in response to this demand. Therefore, there is a demand for a simple and inexpensive ozone concentration measuring device for monitoring the concentration of the atmosphere by installing a large number in the room, instead of the conventional ozone concentration measuring device having a pump and a switching valve. It is growing.

  When using a pump, sampling is possible with a tube even in a thin pipe, and even when measuring a large number of locations, it is possible to measure the tube with a switching device such as a solenoid valve on the measuring device side, but the structure becomes more complicated . Moreover, when the piping tube becomes long, the volume of gas in the piping becomes large, and it takes time to replace the gas, and causes errors due to the influence of decomposition or the like occurring in the piping. Also, when measuring the ozone concentration of the sample gas by comparing the UV absorption amount of the sample gas with the UV absorption amount of the reference gas through the piping tube, the residual ozone in the measuring instrument is not measured in the long piping tube. There were problems such as mixing with the reference gas, and there was a problem that accurate ozone gas measurement was not possible.

Accordingly, the ozone gas concentration measuring method of the present invention is to introduce the sample gas into the measurement flow path from the electrically inlet one end side of a single ozone concentration measurement channel, by measuring the absorption of ultraviolet radiation, then the by introducing reference gas from the other end side of the guide inlet of the measurement flow path in the measurement flow path to measure the absorption of ultraviolet radiation, and compares the UV absorption of the ultraviolet absorption and the reference gas obtained sample gas Thus, in measuring the ozone concentration of the sample gas, the same gas as the sample gas is passed through the inlet on the other end side where the catalyst for ozone decomposition is disposed, thereby generating a reference gas, In measuring the respective ultraviolet absorption amounts of the reference gas, the sample gas and the reference gas are caused to flow in opposite directions in the measurement channel.
According to this, it is possible to prevent the residual ozone in the measuring instrument from mixing with the reference gas as much as possible by causing the gas to flow backward in a single measurement channel, and to measure the ozone concentration of the sample gas. , by directly installed in each location to be measured, it is possible to eliminate, as mentioned earlier, the adverse effects of sampling.

As an apparatus for carrying out this method, the apparatus has a single ozone gas measurement channel having a sample gas inlet on one end and a reference gas inlet on the other end. A reference gas for providing a reference gas from the same gas as the sample gas at the reference gas inlet is provided with a sample gas introduction fan that provides a flow in the opposite direction of the sample gas and the reference gas in the measurement channel. A generator is provided, and an ozone concentration measuring device in which an ozone decomposition catalyst is arranged in the reference gas generator is used.
Here, the reference gas can be introduced into the ozone gas measurement channel by rotating the sample gas introduction fan in the reverse direction. As another example, the sample gas introduction fan and the reference gas introduction fan may be provided separately.

Such an ozone concentration measuring flow path, a sample gas and a reference gas, by introducing a fan, is backflow alternately from different inlet to a single measurement flow path, and an ultraviolet absorption of the sample gas , by comparing the UV absorption of the reference gas, obtained in measuring the ozone concentration of the sample gas, conventionally, a reference gas, granular or activated carbon, forced to configuration sandwiches the manganese dioxide with a nonwoven fabric or the like There was no pressure loss.
For this reason , it has been necessary to always replace the gas in the measurement flow path with a predetermined one by operating a high-pressure pump or switching valve. In recent years, however, a high-performance ozone decomposition catalyst with a small pressure loss constructed as a honeycomb structure has been put to practical use. Ri Na as reduction, since the rectifying effect by placing the honeycomb ozone cracking catalyst in the reference gas generator is obtained, in this case, addition can be omitted rectification grid, the high-pressure pump and the switching valve operation always the gas in the measurement channel in the there is no need to replace a given thing, as described above, it is possible to correct ozone concentration measured in a simple introduction method using the fan.

  As described above, the present invention does not require a pump device, a switching valve, or the like, and is configured by a combination of a simple and inexpensive measurement flow path, an inlet, and a fan, so that quick and accurate ozone concentration measurement can be performed. it can. Since such a simple measuring device can be manufactured at a low cost, it can be placed in a suitable place in the room where equipment with an ozone generating function is installed. It is possible to prevent adverse effects on the above.

The ozone concentration measuring method and apparatus of the present invention will be described based on an embodiment conceptually shown in FIG.
As shown in FIG. 1, on one end side of the ozone gas measurement channel 1 connects the sample gas inlet 4 arranged to sample gas inlet fan 2 and flow control grid 3, also the other side of the measurement flow path 1 the reference gas generation inlet fan 5, the reference gas generator 6 and the reference gas inlet 7 respectively disposed flow control grid 3 is connected.
Here, one end of the measurement channel 1, while arranging the ultraviolet lamps (low-pressure mercury lamp) 8, the other end of the measuring channel 1 that the ultraviolet sensor 9, and an ultraviolet light-emitting circuit 10 and the measurement circuit 11 are connected to a display and calculator 12. The display / calculator 12 includes a control mechanism 13 that controls the operation of the sample gas introduction fan 2 and the reference gas generation introduction fan 5.

In measuring the ozone concentration using this apparatus, first, ozone is uniformly dispersed through the rectifying grid 3 by the sample gas introduction fan 2 from the sample gas introduction port 4 of the measurement channel 1. a manner, by introducing a sample gas into the measurement flow path 1, an ultraviolet absorbing amount emitted from the ultraviolet lamp 8, as measured by the UV sensor 9.
Next, the reference gas is introduced into the measurement channel 1 from the reference gas introduction port 7 through the reference gas generation introduction fan 5 , the reference gas generator 6, and the rectifying grid , and irradiated from the ultraviolet lamp 8. The UV absorption amount is measured by the UV sensor 9.
The first measured ultraviolet absorption amount and the next measured ultraviolet absorption amount are displayed and compared with the computer 12, and the measurement result is numerically displayed. In addition, when the occurrence of ozone concentration exceeding the reference value is detected, an alarm is issued. The required display, such as emitting.

The reference gas generator 6 is provided with an ozone decomposition catalyst.
As this catalyst, a high-purity activated carbon material or a non-noble metal catalyst molded into a honeycomb shape is used. The number of cells in a honeycomb shape is a 23? 78 cells / square centimeter, the ozone concentration in the case of 5ppm or less high purity activated carbon material, also, high-purity activated carbon material and the non-noble metal in the case of the range of 5~1000ppm A catalyst is mixed, and when it exceeds 1000 ppm, a non-noble metal catalyst is exclusively used.

  The ozone concentration measuring apparatus according to the present invention does not require a pump, a valve device, etc., and can consolidate not only the measuring unit but also the control unit, the power source, etc. in a compact box, and can be carried and arranged at a place to be measured. Therefore, it is possible to easily measure the ozone concentration at a location where ozone generation, sterilization, etc. is performed such as a manufacturing facility, a chemical plant, a hospital, or a business office.

It is a conceptual diagram of the ozone concentration measuring apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measurement flow path 2 Sample gas introduction fan 3 Rectification grid 4 Sample gas introduction port 5 Reference gas generation introduction fan 6 Reference gas generator 7 Reference gas introduction port 8 Ultraviolet lamp 9 Ultraviolet sensor 10 Light emission circuit 11 Measurement circuit 12 Display and calculation 13 Control circuit

Claims (2)

Is introduced from the guide inlet one end side of a single ozone concentration measuring channel the sample gas in the measurement flow path, to measure the absorption of ultraviolet radiation, then the conductive inlet of the other end side of the measurement channel Measure the ozone concentration of the sample gas by introducing the reference gas into the measurement channel and measuring the amount of UV absorption, and comparing the UV absorption amount of the obtained sample gas with the UV absorption amount of the reference gas. Hitting
A reference gas is generated by passing the same gas as the sample gas through the inlet on the other end side where the catalyst for ozone decomposition is disposed,
An ozone gas concentration measurement method in which sample gas and reference gas flow in opposite directions in the measurement channel when measuring the ultraviolet absorption amount of each of sample gas and reference gas . An ozone concentration measuring device comprising a single ozone gas measurement channel having a sample gas introduction port on one end side and a reference gas introduction port on the other end side,
The sample gas introduction port is provided with a sample gas introduction fan that causes the flow of the sample gas and the reference gas in the reverse direction in the measurement channel, and the reference gas introduction port is provided with a reference from the same gas as the sample gas. An ozone concentration measuring apparatus comprising a reference gas generator for generating gas, and an ozone decomposition catalyst disposed in the reference gas generator .

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