JPH0125307Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an apparatus for observing sedimentation of suspended particles.

Dynamic microscopy is a device that observes the sedimentation of suspended particles in gas and measures the particle size distribution of the particles. In this dynamic microscopy device, a gas to be measured is introduced into a sedimentation cell, and the sedimentation of suspended particles within the cell is observed using a microscope through an observation window provided on the top surface of the cell. With conventional devices, when the temperature of the gas to be measured is higher than the temperature of the outside world, for example when measuring gas discharged from an internal combustion engine or combustion furnace, condensation occurs due to the large temperature difference with the surrounding air. This may cause the observation window to fog up, and gas convection may occur within the cell during the cooling process of the high-temperature gas, making it impossible to observe sedimentation in the stationary fluid. Since the temperature of the container changes when the temperature of the container changes, there is a drawback that sedimentation of particles cannot be observed accurately.

Furthermore, there has been an apparatus having a structure in which the gas to be measured is introduced into a container surrounding the sedimentation cell in order to maintain the measurement temperature of the sedimentation cell. However, as mentioned above, when the temperature of the gas to be measured is higher than the ambient temperature, condensation occurs and the inside of the container corrodes.
Furthermore, the exhaust gas from internal combustion engines, combustion furnaces, etc. is not always at a constant temperature, but has temperature fluctuations, making it impossible to maintain a stable heat retention state.

The purpose of this invention is to eliminate the above-mentioned conventional drawbacks,
An object of the present invention is to provide a floating particle sedimentation observation device that can accurately observe the sedimentation of suspended particles in a stationary fluid without being affected by the ambient atmosphere or temperature fluctuations of a gas to be measured.

In order to achieve the above object, this device includes a container that supports the sedimentation cell by a conduit for introducing a gas to be measured into the sedimentation cell, thereby forming a space around the sedimentation cell that is isolated from the outside world; a circulation passage for introducing a heat transfer medium for heat retention into the space; a control valve provided at the entrance of the conduit; a first temperature sensor for measuring the temperature of the gas to be measured; and a first temperature sensor for measuring the temperature of the heat transfer medium. and means for controlling the temperature of the heat transfer medium so that the temperature measured by the second temperature sensor approaches the temperature measured by the first temperature sensor by an allowable temperature difference. It is characterized by having the following.

The heat transfer medium is preferably a clean gas or liquid free of airborne particles. Further, the above-mentioned allowable temperature difference refers to a value within a range in which the gas to be measured does not cause convection within the sedimentation cell and does not condense on the surface of the sedimentation cell.

Hereinafter, embodiments of this invention will be described based on the drawings.

FIG. 1 is a configuration diagram showing the above embodiment. Second
The figure is a sectional view taken along the line AA in FIG. The sedimentation cell 3 is a cylindrical container whose upper surface has an observation window 5 and whose lower surface is made of a transparent material, and communicates with the conduit 4 at the side surface in a direction perpendicular to the cylindrical axis. The distance between the upper and lower surfaces is approximately equal to the diameter of the conduit 4. The heat insulating container 2 supports the conduit 4 by fixing it on the side wall, and the sedimentation cell 3
It is a cylindrical container that seals off the outside world. The sedimentation cell 3 has its upper and lower surfaces held horizontally in the hollow portion 8 of the heat-insulating container 2. The upper part of the heat-retaining container 2 is opened to introduce the microscope tube 13, and the space formed between this upper part and the microscope tube 13 is surrounded by a heat-retaining bellows 14. Also,
The head of the bellows 14 is fixed to the microscope tube 13 in order to prevent outside air from entering the heat insulating container 2 due to the vertical movement of the microscope tube 13. Thermal container 2
The side portions of the tubes communicate with passages 11 and 12 provided in a direction perpendicular to the held conduit 4 for inflow and outflow of a heat transfer medium such as air, oil, or water. Furthermore, the passages 11, 12 communicate with a circulation passage 23 in which the heat transfer medium is circulated. The lower part of the heat insulating container 2 is formed of a heat insulator 15. Electromagnetic valves 1a and 1b are provided at the inlet 9 and outlet 10 of the gas to be measured in the conduit 4, respectively. Thermal container 2 including bellows 14, conduit 4 and valves 1a, 1b
is surrounded by a heat insulating member 7 and isolated from the outside air. Note that near the bottom surface of the heat-insulating container 2, a portion of the heat insulating member 7 is removed for connection to other measurement system devices. A purge valve 20 is provided in a gas passage 27 to be measured leading to the inlet 9 of the conduit 4, and a temperature sensor 1 measures the gas temperature in the passage 27.
6 is provided.

Note that the outside of the passage 27 is covered with a heat insulating material 6. Further, a temperature sensor 17 is provided within the heat insulating container 2 to measure the temperature of the heat transfer medium. The circulation passage 23 is provided with an inlet electromagnetic valve 24a and an outlet electromagnetic valve 24b through which the heat transfer medium flows in and out, and a heating device 21 consisting of a heater and a fan, and communicates with the heat insulation container 2 via passages 11 and 12. The entire structure is kept warm by a heat insulating material 22.

The comparator 18 inputs the outputs of the temperature sensors 16 and 17, stores in the memory 26 the temperature at which the gas to be measured is introduced into the sedimentation cell 3 at the time of measurement, and also compares the temperature of the gas to be measured and the temperature in the heat insulating container 2. The temperatures of the heat transfer media are compared and output to the temperature control device 19. Based on the output signal from the comparator 18, the temperature adjustment device 19 supplies power to the heating device 21 and controls electromagnetic control so that the temperature difference between the gas to be measured and the heat transfer medium in the heat insulation container 2 becomes an allowable value. Controls opening and closing of valves 24a and 24b. This allowable temperature difference is set in advance, and is a value ranging from zero temperature difference to a range in which no convection of the gas to be measured occurs within the sedimentation cell 3 and no dew condensation occurs on the surface of the sedimentation cell 3. The valve opening/closing control device 25 controls the electromagnetic valves 1a and 1b not to open based on the output signal from the comparator 18 until the temperature adjustment by the temperature adjustment device 19 is completed. In addition, by incorporating a mantle heater equipped with a temperature controller into the heat insulating member 7, the inside can be maintained in a completely constant temperature state.

Next, the operation and usage of the above embodiment will be explained.

First, before introducing the gas to be measured into the settling cell 3, the temperature difference between the gas to be measured and the heat transfer medium in the heat insulating container 2 is controlled to a predetermined value. In this case, the purge valve 20 is open, and the valves 1a, 1
b is closed. In this state, the gas to be measured is not introduced into the sedimentation cell 3 yet. The temperatures of the gas to be measured and the heat transfer medium measured by the temperature sensors 16 and 17 are introduced into a comparator 18 and compared. The temperature control device 19 operates according to the compared results. When the temperature of the gas to be measured is higher than the temperature of the heat transfer medium, power is supplied to the heater of the heating device 21, and the heat transfer medium is heated until it reaches a predetermined temperature difference from the temperature of the gas to be measured. If the heat transfer medium is higher in temperature, the valves 24a and 24b are opened, and the heat transfer medium at a lower temperature is newly mixed in to cool the heat transfer medium to the predetermined temperature difference. In this way,
When the temperature of the heat transfer medium in the heat insulating container 2 which has the predetermined temperature difference from the gas to be measured is obtained, the valves 24a and 24b are closed, and the circulation passage 23 is closed. Therefore, purge valve 2
0 is closed, and the valve opening/closing control device 2
5 opens the valves 1a and 1b, and the gas to be measured is introduced into the sedimentation cell 3. After a predetermined amount of the gas to be measured is introduced, the valves 1a and 1b are closed and the gas is confined within the sedimentation cell 3. The temperature of the gas to be measured when introduced into the sedimentation cell 3 is stored in the memory 26, and the temperature of the heat transfer medium remains within the predetermined temperature difference with respect to the stored temperature even during measurement. The heat transfer medium circulates in the circulation passage 23, controlled by the temperature control device 19 to maintain the temperature. The suspended particles contained in the gas to be measured start settling when the gas to be measured is confined in the sedimentation cell 3.
Immediately perform observation using a microscope. During this observation, the temperature around the sedimentation cell 3 is maintained at the temperature of the gas to be measured and the predetermined temperature difference.
No convection occurs within the sedimentation cell 3, and no dew condensation occurs on the observation window 5 of the sedimentation cell 3. Therefore,
The sedimentation of suspended particles in the gas to be measured can be observed in such an optimal state, and an accurate particle size distribution can be obtained.

As mentioned above, according to this invention, suspended particles settling in a stationary fluid can be observed,
It is possible to obtain a sedimentation observation device for suspended particles that can perform a wide range of sedimentation observation including high-temperature exhaust gas from combustion furnaces and internal combustion engines.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of this invention. FIG. 2 is a sectional view taken along the line AA in FIG. 1. 1a, 1b...electromagnetic valve, 2...thermal container,
3... Sedimentation cell, 4... Conduit, 5... Observation window, 1
1, 12... passage, 13... microscope tube, 14...
Bellows, 16, 17...Temperature sensor, 18...Comparator, 19...Temperature adjustment device, 23...Circulation passage, 25...Valve opening/closing control device.

Claims (1)

[Scope of utility model registration request] In an apparatus that uses a microscope to observe the sedimentation of suspended particles in a gas to be measured introduced into a sedimentation cell via a conduit, there is provided a space around the sedimentation cell that is isolated from the outside world by supporting the sedimentation cell with the conduit. a circulation passage for introducing a heat transfer medium for heat preservation into the space, a control valve provided at the entrance of the conduit, and a first chamber for measuring the temperature of the gas to be measured.
a second temperature sensor that measures the temperature of the heat transfer medium; and a permissible temperature difference between the temperature measured by the second temperature sensor and the temperature measured by the first temperature sensor. and means for controlling the temperature of the heat transfer medium so that the temperature of the heat transfer medium approaches the temperature of the suspended particles.