JPS649567B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for measuring the dust content in a gaseous fluid. This measuring device is particularly advantageous for monitoring fumes generated during operations in the production of construction materials (bricks, concrete blocks), cast iron, steel, non-ferrous metals and pulverulent materials such as cement.

Most metallurgical operations produce smoke. The total content of dust, solid or gaseous, contained in this smoke is related to the progress of the metallurgical operation. When these are measured, the smoke therefore provides the operator with information regarding the progress of the metallurgical operation. This allows the operator to better control the metallurgical operation.

The currently widely used method for measuring the dust content of smoke (gas fluid) flowing through a given duct is the isokinetic method. A portion of the smoke is collected in a vacuum chamber, and the collected smoke sample is passed through to collect dust, which is then dried and finally weighed in a laboratory.

This method has the disadvantage that it can only be measured 5 to 6 times a day and it takes time to obtain data, and the measurement operation is expensive to carry out industrially in the field. . In addition, this method is completely discontinuous and results are only available after at least 24 hours.
This does not allow effective on-the-spot adjustments to metallurgical operations.

There are currently two main industrial methods for continuously evaluating the amount of dust:

One method is to measure the amount of dust collected on a filter by absorbing radiation. This method still has the problem that there are many discontinuities, and the absorption of radiation varies depending on the properties (chemical composition, particle size, etc.) of the dust collected by the filter.

The other method is an optical method in which a light beam (visible spectrum or infrared spectrum) is directed from a light emitter to the passing smoke and the attenuation is measured by a light receiver. This method has the significant drawback of being only qualitative (attenuation is related to the cross-sectional area of the particles and not to the mass of the dust).

Thus, currently, to the best of the inventor's knowledge, the dust content (weight) in industrially generated smoke is
There is no industrial measurement method that satisfactorily measures .

Therefore, the present invention solves the above-mentioned drawbacks and reduces the dust content (by weight) in a gaseous fluid which is substantially continuous.
An object of the present invention is to provide a measuring device for carrying out a measuring method.

The measuring device of the invention takes a portion of the gaseous fluid to be measured, preferably uniformly; this sampling is carried out continuously; the sample taken is passed through a filter for a predetermined time; This is repeated, preferably at regular intervals; the filter is weighed while the sample is bypassed; this weighing is carried out using a force sensor of suitable sensitivity and measuring range (e.g. spring balance, mechanical balance). During this weighing period, the collected smoke bypasses the filter and is discharged;
The above cycle is repeated, for example, until the filter is completely saturated; as this cycle is repeated, the weight value of the filter increases, and by calculating the difference between each cycle, the smoke The purpose of this method is to understand the fluctuations in the dust content of the air.

Once the flow rate of the sampled gas is measured and converted to the standard state (0°C, 760mmHg), the total dust content in the smoke during the sampling period can be calculated in g/ ^Nm3 by integrating this measured value. It can be calculated. It is also possible to measure the humidity of the gas and to correct the dust content in g/Nm ³ when dry.

The method of the present invention preferably allows moisture to be removed from the dust layer adhering to the filter between the time of stopping sampling (i.e., discontinuing the supply of smoke to the filter) and the time of starting the weighing operation of the filter. 100 min under pressure with a dust-free, dry, neutral or inert gas (e.g. _N2 ) for a short period of time to remove
Pass through the filter at a temperature above 150°C (preferably between 150°C and 200°C). This allows the dust to be dried and the dry material to be weighed with virtually no loss of time. To improve this operation, the filter itself can also be exposed to similar temperatures for short periods of time (preferably for the same amount of time and at the same temperature).

As mentioned above, the present invention makes it possible to measure the dust content of smoke substantially continuously, e.g.
Dust content is measured repeatedly throughout the day or week, with each measurement interval being 15 minutes. Note that the filter is very fine (does not allow dust of 1 μm or larger to pass through) and has a large capacity (for example, it can be used for about a week without difficulty without being replaced or cleaned).

The measuring device of the present invention is characterized in that when the dust filter is in the sampling position, the dust filter is airtightly surrounded, and facing the inlet side of the dust filter, the intake conduit and the outlet side of the dust filter are connected to each other. a chamber having a discharge conduit facing towards it; when the dust filter is removed from the sampling position and in the weighing position, the dust filter does not make any contact with said chamber and the weight of the dust filter is completely transferred to the weighing device. The apparatus is equipped with a device for weighing the dust filter in the manner described above.

Hereinafter, the present invention will be specifically described with reference to the accompanying drawings. 1 and 2 are diagrams showing a first embodiment of the present invention. In the figure, 1 is a duct through which smoke flows, 2 is a direction in which smoke flows, and 3 is a pipe for collecting part of the smoke. Smoke samples are taken isokinetically. 4 is a valve that is closed during the sample collection period, 5 and 6 are valves that are open during the sample collection period, 7 is a connecting pipe that leads the sample, 8 is an intake pipe device, 10 is a filter, and 9 is a valve that is open during the sample collection period. an internal space of the filter 10; 11 is a chamber surrounding the filter 10;
12 is a discharge conduit from the chamber 11, and 13 is an exhaust pipe. The smoke from pipe 3, with valve 4 closed and valves 5 and 6 open, passes through connecting pipe 7 to intake conduit arrangement 8 and through filter 10, where it is filtered for dust before being discharged. is discharged through conduit 12. When valve 4 is opened and valves 5 and 6 are closed, smoke from pipe 3 bypasses filter 10 and goes to exhaust pipe 13 where it is exhausted. Thus, smoke flows continuously from the duct 1 to the pipe 3, but the smoke is sometimes passed through the filter 10 (during sample collection) and sometimes bypassed (during weighing). 14 is a stand, 15 and 16 are vibration dampers, 1
7 is a precision electronic balance; 18 is a specially shaped support member for supporting the filter to be weighed; 19 is a member that closes the lower end of the internal space 9 of the filter 10; 20
29 is a core rod connected to the member 19 and placed tightly on the support member 18; 29 is a core rod 20;
28 is an annular member that accommodates the circular flange 29 with play, 27 is a control disk to which the annular member 28 is attached, and 26 is three pieces that hold this control disk 27. bar, 25 is bar 2
The upper end of frame 6 is connected to frame 23, and numeral 23 is a jack that moves frame 25 in the direction of arrow 24. The filter 10 is moved up and down by this jack 23. When the filter 10 is brought into the upper position (the position shown) by the jack 23, the upper end of the interior space 9 of the filter 10 is sealed against the intake conduit device 8 by the O-ring 21 and the chamber 11 is sealed by an O-ring 22. The chamber 11 is formed by a box 31 whose bottom plate 30 has an opening 34 through which a member 19 closing the lower end of the interior space 9 of the filter 10 passes. Note that the bottom plate 30 is fixed to a chassis 32.
The bottom plate 30 also has holes through which the three rods 26 pass. When the filter 10 is brought to the lower position by the jack 23, the O-rings 21, 22
are separated from the opposing members, respectively, and the filter 1
0 is placed on the electronic balance 17. Then, when the annular member 28 is lifted off the circular collar 29, the filter 10 is attached to the support member 18 of the electronic balance 17 and the core rod 20.
With this, a state is achieved in which the balance is held on the electronic balance 17 and is not touching anything else.

The measuring device of the present invention is constructed as described above, in which the filter 10 is lifted up by the jack 23, the O-rings 21 and 22 are brought into contact with each member to maintain the chamber 11 in an airtight state, and the chamber 11 is maintained in an airtight state. 4
By closing the valves 5 and 6 and opening the valves 5 and 6, smoke from the pipe 3 enters the interior space 9 of the filter 10 from the connecting pipe 7 through the intake conduit arrangement 8 and crosses the filter 10 into the chamber. 11 and from there is discharged through a discharge conduit 12 to an exhaust pipe 13. In this way, a portion of the smoke is collected from the duct 1 and the dust is collected in the filter 10.

After the filter has passed through the filter, valves 5 and 6 are closed.
Close and open valve 4. Thus, the smoke from the pipe 3 bypasses the filter 10 and is discharged directly into the exhaust pipe 13. During this time, the filter 10 is placed on the electronic balance 17 by operating the jack 23 in the direction of the arrow 24, and the weight of the dust collected on the filter 10 is measured.

When the weighing process is completed, the jack 23 is operated in the direction opposite to the arrow 24 to lift the filter 10 and bring the O-rings 21 and 22 into contact with their respective members. Then, close valve 4, open valves 5 and 6,
The filter filling process is performed again, and this cycle is repeated thereafter.

In addition, in the above explanation, the intake conduit device 8
The valve 35 of the conduit 33 leading to remains closed. By the way, the function of this conduit 33 is to completely dry the dust collected by the filter and measure the dry weight of the dust. For this purpose, dry neutral gas at an appropriate temperature is supplied to conduit 3.
3 into the filter 10. In this case, when the filter filling process is completed, valve 4 is opened, valve 5 is closed, valve 6 is kept open, and valve 35 is closed.
This is done by opening. Thus, dry, neutral, dust-free gas at a suitable temperature (e.g. 150-200℃)
compressed nitrogen) is briefly blown into the filter 10, thereby drying the dust.

Preferably, the filter is a cylinder made of a suitable porous paper and is held within a coarse metal mesh to prevent the paper from tearing.

FIG. 3 is a diagram showing another embodiment of the present invention. In this embodiment, the manner in which the filter 10 is moved up and down is different from that in the first embodiment. In the figure, 7, 9-12, 14-22, and 31 are exactly the same as those of the first embodiment. 56 is an intake conduit integrally connected to the connecting pipe 7; 54 is a plate provided at the upper end of the filter 10; 55 is a central hole formed in 54 through which the conduit 56 passes with play; 53 is a perforated hole; This is the side wall. This perforated side wall 53 is for preventing the filter 10 from deforming. box 31
has a hole 67 through which conduit 56 passes. Conduit 56 is movable up and down relative to hole 67. This moving part is O
- sealed by ring 68; 65
is a plate attached to conduit 56. This board 6
A bellows 66 is attached between 5 and the box 31. 64 is an airtight chamber formed by bellows 66;
Reference numeral 2 denotes a hole formed in the box 31 for introducing compressed gas into the airtight chamber 64 as shown by an arrow 63. When compressed gas is introduced into the airtight chamber 64, the bellows 6
6 is extended and the plate 65 is lowered. 71 is a bottom plate of the box 31, and 72 is an opening formed in the bottom plate 71. The core rod 20 extends with play through the opening 72 to the outside of the box 31. This core rod 20 consists of two members, which are flexibly connected by a spring 74.

This embodiment is configured as described above,
The compressed gas is introduced into the airtight chamber 64 through the hole 62 by the arrow 63.
When the plate 65 is introduced in the direction of , the plate 65 is lowered. The plate 65 contacts the plate 54 at the upper end of the filter 10 and lowers the filter 10. Since the filter 10 has a spring 74 in its core rod 20, the filter 10 is allowed to fall. Thus filter 10
The lower end member 19 is brought into contact with the bottom plate 71 of the box 31. As a result, the filter 10 has a plate 65 and a bottom plate 7.
1, the O-ring 21 hermetically closes the central hole 55 of the plate 54, and the O-ring 22 hermetically closes the opening 77 of the bottom plate 71 of the box 31. Thus, when smoke is introduced through the conduit 56, it enters the interior space 9 of the filter 10 and exits the chamber 11 only across the filter 10. This room 1
1, the smoke exits from the box 31 to the connected discharge conduit 12.
is discharged.

When the compressed gas is released or sucked from the airtight chamber 64, the bellows 66 contracts and the plate 65 moves upward. As a result, the filter 10 is released from being held between the plate 65 and the bottom plate 71, and the spring 74 of the core rod 20 mounted on the electronic balance 17 extends, so that the lower end member 19 of the filter 10
is lifted from the bottom plate 71 of the box 31. Therefore, the weight of the filter 10 can be measured.

The manner in which the dust content is measured using the apparatus of this embodiment is the same as that of the first embodiment. In this embodiment, O-ring 21 is located between plates 65 and 54, and O-ring 22 is also located between plates 19 and 71, so that the first
The O-rings 21, 22 have the advantage of being completely unaffected by twisting or shearing forces than shown in the figures. This ensures a long lifetime and allows an increased number of measurement repetitions. Also, in this embodiment, since the opening 72 is small, the balance is less susceptible to contamination due to the accumulation of dust and is hardly affected.

Incidentally, it is preferable to provide a device for measuring the instantaneous flow rate of the gas to be sampled at a suitable location on the pipe 3, and a device for calculating the volume of the gas sampled during each sampling period.

As can be seen from the above description, according to the present invention it is possible to quickly and repeatedly measure the dust content in a gas stream, and to determine the difference (i.e. the increment) in the weight of dust that accumulates on the filter. This makes it possible to know changes in the dust content contained in the gas flow.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention. FIG. 2 is a plan view of a portion of FIG. 1. FIG. 3 shows another embodiment of the present invention, and is a schematic diagram of its main parts. In the figure, 3 is a device that continuously collects samples, 5 is a device that prevents the sample from passing through, 7 is a device that guides the sample, 8 and 56 are intake conduit devices, and 1
0 is a filter, 11 is a chamber surrounding the filter, 1
2 is a discharge conduit, 17 is a weighing device, and 23 and 66 are devices for moving the filter.

Claims (1)

[Claims] 1. An apparatus for measuring the dust content of a gaseous fluid containing dust, which: (a) has a cylindrical shape, the axis of which is vertical;
a dust filter having a perforated cylindrical side wall, the lower end being closed and the upper end being open; (b) moving said dust filter along its vertical axis between a sampling position and a weighing position; (c) a device surrounding said dust filter, comprising an intake conduit facing the upper open end of the dust filter, an outlet conduit facing the perforated cylindrical side wall of the dust filter, and a lower part of the dust filter; (d) sealing said opening in the bottom of the chamber and said opening in the upper end of the dust filter when the dust filter is in the sampling position; (e) A device for weighing a dust filter in a weighing position, wherein the dust filter in the weighing position is not enclosed in any airtight manner in the chamber and the weight of the dust filter is completely absorbed by the weighing device. (f) a device for continuously taking samples of a gaseous fluid containing dust; (g) a device for weighing a dust filter in such a manner as to and (h) a device for preventing the sample from passing through the dust filter in the weighing position. A device that measures quantities. 2. Device for measuring dust content in a gaseous fluid as claimed in claim 1, wherein the intake conduit is oriented along the vertical axis of the dust filter. 3. A device for measuring dust content in a gaseous fluid according to claim 1, comprising a device for measuring the instantaneous flow rate of a continuously collected sample. 4. A device for measuring dust content in a gaseous fluid according to claim 1, comprising a device for passing dry inert gas through a dust filter at a temperature of 100° C. or higher. 5. A device for measuring dust content in a gaseous fluid according to claim 1, wherein the weighing device comprises a precision balance having a data storage device. 6. A device for measuring dust content in a gaseous fluid according to claim 3, wherein the precision balance has a vibration damper.