JPH0436431Y2 - - Google Patents

Description

[Detailed description of the invention] <Field of industrial application> The present invention relates to a sampling device for measuring the concentration of gas, such as sampling and measuring harmful gases (NOx, etc., hereinafter simply referred to as gases) including dust, etc. It is.

<Prior Art> Conventionally, as a means for detecting gas concentration in exhaust gas discharged from an electric furnace or the like which is generally used, a method is adopted in which a sampling gas is taken out directly from a flue through a cyclone dust remover.

That is, the gas sampled from the flue is contaminated with dust and the like, and as it is inconvenient for measurement, the gas must be introduced into a cyclone dust remover to remove the dust. However, the cyclone had a poor collection effect, and there was no other good method.

<Problems to be solved by the invention> In view of the above-mentioned circumstances, the present invention uses a vertical bag filter that eliminates the need to replace the filter each time to filter gas containing dust, and a pressure/flow adjustment process to obtain dust particles suitable for use as a sample. Collect only the gas that is not contaminated with
The object of the present invention is to provide a sampling device for measuring the concentration of harmful gases, which enables efficient measurement.

<Means for solving the problem> The present invention consists of a bag filter with coarse mesh and a food filter with fine mesh at the upper end of the hopper, which has an inflow duct on one side that leads from a gas generation source such as an electric furnace. A double bag-shaped sampling filter device is installed vertically, and a sampling gas outlet pipe connected to a part of the outer hood filter of the sampling filter device is led to a pressure flow regulator, and the sampling gas outlet pipe is located at the center of the pressure flow regulator. The outlet of the sample gas outlet pipe connected to the measuring instrument faces the retention chamber formed at the outlet of the filter chamber.

<Function> Due to the above configuration, gas introduced from the flue is guided to a sampling filter device equipped with an inner and outer double-structured filter each having a different resistance value.
The dust contained in the gas is primarily filtered using a double filter, and only the necessary gas is guided from the outer filter section to the pressure regulator, and then filtered again using the pressure flow regulator for secondary filtration. This filter-passing gas is caused to stagnate at the outlet of the filter chamber due to the difference in flow velocity of the non-filter-passing gas that directly circulates around the outer periphery, and this dust-free stagnant gas (sample gas)
Since only the gas is allowed to flow into the measuring instrument side, gas suitable for measurement can be obtained.

<Example> Hereinafter, the present invention will be explained based on the drawings of the example.

Reference numeral 1 indicates an inner bag filter 2 with relatively coarse mesh, and a fine outer food filter 3 with high resistance, which is made of a Tetoron bag or the like arranged on the outer periphery at a predetermined interval.
This is a sampling filter device having a double filter configuration formed by the above-mentioned method.A hopper 4 having an inflow duct 5 provided on one side is attached to the lower end of the sampling filter device 1. In this case, the gas A flowing into the hopper 4 from the inflow duct 5 communicating with the gas generation facility rises through the bag filter 2 which opens at the center of the blocking wall 4a arranged around the upper part. There is.

In addition, the structure of this bag filter 2 has a plurality of filter tubes, each part of which is supported by a retainer 2a, giving the overall shape of a filter tube type bag, and the uppermost filter tube end is closed with a top plate 2b, so that it can be used for hanging chains, etc. It is adapted to be suspended by a fixture 16. Further, the outer hood filter 3 has a cylindrical bag shape that encloses the inner bag filter 2, and its upper end is narrowed into a purse-like shape, but communicates with the atmosphere through a gap a. Reference numeral 6 denotes a ring-shaped sampling gas sampling section installed approximately in the middle of the outer hood filter 3, and the tip of the outlet pipe 7 connected to the sampling port 6a of the gas sampling section 6 is connected to a pressure flow rate having a double housing structure. It faces directly below the filter chamber 9 disposed at the center of the regulator 8, and allows a portion of the introduced gas A to flow into the filter chamber 9, and a portion of the gas A to flow through the communication port 10 formed in the leg portion 9a. It is made to branch into the outer peripheral chamber 11 surrounding the filter chamber 9. In this case, the filter chamber 9 is fitted with a meandering paper filter 12 in the middle, and the upper end of the filter 9 is formed with a converging wall 9b that is curved inward to narrow the outer peripheral chamber 11. The sample gas outlet 14 is formed in such a way that a ventilating effect is obtained when the non-filter-passing gas A passes through the gap 1 between the filter chamber 9 and the retention chamber 13 in the convergence wall 9b at the upper end of the filter chamber 9.
A meter 17 for measuring the concentration of gas such as Nox is attached to the tip of an outlet pipe 15 connected to the outlet 14.

Next, this sampling device will be explained in detail using the system diagram of the factory facility shown in Fig. 3.
The exhaust gas mixed with the dust generated from 4 is first led to the combustion tower 18, and is then passed through the preheating device 19 and the auxiliary blower 2.
0, and is force-fed through a main blower 21 to a dust collector 22 equipped with a sampling filter device 1.

Here, the gas A flowing into the sampling filter device 1 equipped with the sampling gas sampling section 6
is introduced into the central inner bug filter 2,
When passing through the bag filter 2, the dust B mixed in the gas A is primarily filtered. On the other hand, the gas A that has passed through the bag filter 2 rises while being secured in the space between the outer hood filters 3, and is discharged to the atmosphere through the gap a opened at the upper end. Thus, the gas A flowing into the sampling filter device 1 is always in a flowing state. During continuous use, if the bag filter 2 and hood filter 3 become clogged with dust, etc., the dust can be removed by driving the backwashing blower 23 and introducing air, for example.
It is collected in a hopper 4 and discharged as appropriate.

Next, a part of the primary filtered gas A in the hood filter 3 is transferred to the sampling filter device 1.
The gas flows from a sampling port 6a of a sampling gas sampling section 6 provided near the center of the sampling gas through a lead-out pipe 7 into a pressure flow rate regulator 8. In this case, most of the gas A is secondarily filtered by the paper filter 12 in the filter chamber 9 located directly above the inlet, and is filtered through the opening 9c at the tip.
However, at this time, a part of the gas A flows into the outer chamber 11 through the lower communication port 10,
Due to the acceleration at the surface of the convergent wall 9b of the filter chamber 9 and the non-filter passing conditions, the flow velocity is accelerated compared to the gas passing through the filter 12, and therefore the opening 9c of the convergent wall 9b at the outlet of the filter chamber 9 is This accelerated flow rate creates a kind of sealing state, and the inside of the converging wall 9b is used as a retention chamber 13, so that a completely filtered sampling gas A' containing no dust B is obtained and is sent from the outlet pipe 15 to the measuring instrument 17. It becomes something that can be guided.

<Effects of the invention> As mentioned above, the present invention introduces gas mixed with dust introduced from the flue to a sampling filter device having a double structure of inner and outer filters with different resistance values, and performs primary filtration, and also performs filtration. Securing the gas while maintaining a flowing state in the space between the inner bag filter and the outer hood filter of the sampling filter device, and guiding it from the sampling gas sampling section to a pressure flow regulator for secondary filtration,
The gas that passes through the filter chamber and the gas that passes through the outer chamber are divided into two, and due to the difference in gas flow velocity, the gas that has passed through the filter chamber is retained and introduced into the measuring instrument, so that only dust-free gas can be produced. can be sampled, making it possible to accurately measure gas concentrations. In addition, since the configuration is much simpler than a sampling device using a conventional cyclone dust removal device, maintenance and inspection work is easy and continuous measurement is possible. It goes without saying that gas concentration measurement using the sampling filter device of the present invention is not limited to detecting only Nox, but can also be used for any gas containing dust.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is an explanatory diagram of the entire device, FIG. 2 is a sectional view of the pressure flow regulator, and FIG. 3 is a system diagram of the device in use. DESCRIPTION OF SYMBOLS 1... Sampling filter device, 2... Inner bag filter, 3... Outer hood filter, 4... Hopper, 6... Sampling gas sampling section, 8... Pressure flow regulator, 9... Filter chamber, 9b... ... Convergence wall, 11 ... Peripheral chamber, 12 ...
Filter, 13...retention chamber, 14...sample gas outlet.

Claims (1)

[Scope of utility model registration request] A double bag type sampling filter device formed by a vertically installed coarse inner filter and a fine outer hood filter equipped with a hopper having a gas inlet at the lower end, and a sampling gas outlet pipe connected to the outer periphery of the sampling filter device. and a pressure flow regulator communicating with the pressure flow regulator, and the outlet of the sample gas outlet pipe connected to the measuring instrument is made to face the retention chamber formed at the outlet of the filter chamber of the pressure flow regulator. Sampling device for measuring the concentration of harmful gases.