JPH0652970U - Airflow classifier - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an airflow classifier that allows easy adjustment of classification points. [Structure] A pressure measuring hole 40 that opens in a flow passage 9 between the louvers 8 adjacent to one of a large number of louvers 8 provided in the outer circumferential direction of the classification chamber 3 is formed. The pressure measuring device 42 is attached to the conduit 41 connected to the pressure measuring hole 40. The flow passage 9 corresponding to the opening degree of the louver 8 is measured by the pressure measuring device 42.
The internal pressure is measured, the flow rate of the secondary air that correlates with the classification point of the powder is obtained from the differential pressure between the measured pressure and the atmospheric pressure at the inlet side of the flow passage, and the relationship between the pressure and the opening of the louver 9 is calculated. Leave as data. When adjusting the classification point after the formation of the classification plant, the pressure in the flow passage 9 is measured by the pressure measuring device 42, and the opening of the louver 8 is adjusted so that the measured pressure matches the data pressure.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an airflow classifier that centrifuges various powders such as toner into coarse powder and fine powder.

[0002]

[Prior art]

 The applicant of the present application has already proposed an air flow classifier that supplies powder into a classifying chamber and swirls the powder to separate it into coarse powder and fine powder. The airflow classifier will be described with reference to FIGS. 1 and 3. In this airflow classifier, powder is supplied from the upper portion into the casing 1 toward the outer periphery of the dispersion chamber 2, and the powder inside the dispersion chamber 2 is supplied. The powder that swirls and descends is made to flow from the annular slit 5 into the classification chamber 3.

Further, the casing 1 is divided into upper and lower parts at the position of the classification chamber 3, and a large number of louvers 8 are provided at equal intervals between the facing parts of the upper casing 6 and the lower casing 7, and the flow between the adjacent louvers 8 is made. The secondary air flowing into the classifying chamber 3 from the passage 9 disperses the powder swirling in the classifying chamber 3 and accelerates the swirling speed.

Then, the coarse powder that is centrifugally separated in the classifying chamber 3 and swirls in the outer peripheral portion of the classifying chamber 3 is introduced into the lower casing 7 from the annular coarse powder discharge groove 10 formed on the lower outer periphery of the classifying chamber 3. It is made to flow in and taken out from the discharge port 11 at the lower end. Further, the fine powder that moves to the center of the classification chamber 3 is taken out from the fine powder discharge tube 12 connected to the center of the bottom of the classification chamber 3.

When the powder is classified using the above-mentioned air stream classifier, the classification point is adjusted by a method of adjusting the opening degree of the damper 14 in the exhaust pipe 13 connected to the upper portion of the dispersion chamber 2, and the classification chamber 3 There is a method of rotating the louver 8 provided on the outer periphery of the louver 8 about the pin 15 to adjust the opening degree.

By the way, the adjustment of the classification point for adjusting the opening degree of the damper 14 is such that when the damper 14 is opened beyond a certain opening, the powder particles scatter, and the particle size adjustment range is small. Therefore, the adjustment of the classification point is performed. A method of adjusting the opening of the louver 8 while changing the opening of the damper 14 to a predetermined opening and changing the inflow amount of secondary air is adopted.

The adjustment of the classification point is usually performed at a test stage before forming a classification plant shown in FIG. 4 and a stage immediately before forming a classification plant and continuously classifying powder. The adjustment at the test stage is performed according to the kind of powder, and the test result is recorded as data.

Here, in the classification plant shown in FIG. 4, a cyclone 30 is connected to the fine powder discharge cylinder 12 of the airflow classifier X to collect the fine powder after classification. Further, the exhaust pipe 31 of the cyclone 30 and the exhaust pipe 13 of the airflow classifier X are connected to a bag filter 32, the suction force of the blower 33 is applied to the bag filter 32, and the exhaust gas of the airflow classifier X and the cyclone 30 is supplied. The powder is removed from the exhaust gas by suctioning into the bag filter 32.

By the way, when adjusting the classification point at the time of powder classification after forming the classification plant, conventionally, the classification plant is batch-operated, and when the operation is stopped, the fine powder collected in the cyclone 30 is taken out to measure the particle size. However, since the opening of the louver 8 is adjusted based on the measurement result, it takes a lot of time and effort to adjust the classification point.

In general, the inflow amount of the secondary air that determines the classification point is correlated with the flow velocity, so that the inflow amount can be known by measuring the flow velocity. Therefore, in order to solve the above-mentioned inconvenience, the applicant of the present invention measures the flow velocity of the secondary air flowing through the flow passage 9 with the Pitot tube, and the measured value is the flow velocity of the data showing the relationship between the flow velocity and the classification point. An airflow classifier in which the opening of the louver 8 is adjusted so that the louver 8 is adjusted to adjust the classification point has already been proposed (Japanese Utility Model Laid-Open No. 4-91776).

The airflow classifier has a feature that the classification point can be finely adjusted and accurately adjusted in the operating state of the classifier.

[0012]

[Problems to be solved by the device]

 By the way, in the above air flow classifier, since the total pressure measurement hole of the pitot tube is installed so as to face the secondary air flow direction, dust is likely to adhere to the total pressure measurement hole, and the adhesion increases the flow velocity. Since it is not possible to measure accurately, maintenance and inspection work must be performed frequently.

The present invention aims to improve the above-mentioned air flow classifier so that it requires almost no maintenance or inspection work, and that the pressure correlated with the flow velocity of the secondary air can always be measured satisfactorily. I am trying.

[0014]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, in the present invention, a pressure measurement hole that opens on a surface facing the flow passage between the louvers adjacent to one of the louvers is formed, and the flow passage is formed in the pressure measurement hole. We adopted a configuration that was equipped with a pressure measuring device that detects the pressure.

[0015]

[Action]

 In the airflow classifier with the above configuration, the pressure inside the flow passage that changes due to the adjustment of the louver opening is measured with a pressure measuring instrument, and the flow velocity of the secondary air flowing through the flow passage is calculated based on the measured value. Adjust the louver opening so that the flow velocity matches the data showing the relationship between the flow velocity and the classification point, and adjust the classification point.

[0016]

【Example】

 In FIG. 1, a large number of louvers 8 arranged in an annular shape are adjusted in opening degree by rotating about a pin 15 shown in FIG. To adjust the opening, each louver 8 may be manually rotated individually after disassembling the upper casing 6 shown in FIG. 1, or an opening adjusting mechanism may be provided and the opening adjusting mechanism may be operated. A large number of louvers 8 may be simultaneously rotated in the same direction.

2 and 3 show an example of the opening adjustment mechanism 20. The opening adjusting mechanism 20 rotatably incorporates an adjusting ring 21 between the upper casing 6 and the louver 8 arranged in an annular shape, and forms a guide hole 22 made of a long hole on the upper surface of each louver 8. On the other hand, the adjusting ring 21 is provided with a pin 23 to be inserted into each of the guide holes 22, and the louvers 8 are simultaneously rotated by the rotation of the adjusting ring 21.

In order to rotate the adjusting ring 21, a gear support frame 24 is attached to the lower outer periphery of the upper casing 6, and a bevel gear 26 that meshes the rotations of the knobs 25 supported by the gear support frame 24 with each other is provided. Is transmitted to the worm shaft 27, and the rotation of the worm 28 provided on the worm shaft 27 is transmitted to the adjustment ring 21 via the worm wheel 29.

The opening adjustment mechanism is not limited to the one shown in the drawing, and other mechanisms may be adopted.

As shown in FIG. 3, one of the louvers 8 is formed with a pressure measuring hole 40 that penetrates from the outer surface to the inner surface, and the opening on the inner surface side faces the flow passage 9.

A conduit 41 is connected to the pressure measuring hole 40, and a pressure measuring device 42 is provided in the conduit 41.

Here, the pressure measuring device 42 may be a Bourdon tube pressure gauge or a V-shaped manometer. In the embodiment, the pressure in the flow passage 9 is detected using the pressure sensor 43, the detection signal output from the pressure sensor 43 is amplified by the amplifier 44, and the pressure is displayed on the meter 45.

With the above configuration, the pressure in the flow passage 9 can be measured by the pressure measuring device 42, and the pressure difference between the measured pressure and the atmospheric pressure on the inlet side of the flow passage allows the flow passage 9 to be measured by Bernoulli's theorem. The flow velocity of the secondary air flowing through can be obtained.

The flow velocity of the secondary air flowing through the flow passage 9 correlates with the opening degree of the louver 8, and the opening degree of the louver 8 differs depending on the classification point of the powder to be classified. Therefore, when adjusting the classification point of the powder in the test stage, the pressure in the flow passage 9 corresponding to the opening of the louver 8 is measured, and the relationship between the opening of the louver 8 and the measured pressure is left as data. At the time of adjusting the classification point after the formation of the classification plant, the classification point can be adjusted by adjusting the opening of the louver 8 based on the data.

In the airflow classifier having the opening adjustment mechanism 20, the louver 8 is simultaneously rotated while measuring the pressure in the flow passage 9, and the measured pressure is made equal to the measured pressure of the above data.

In the case of the examples, the airflow classifier has been shown as a type in which the powder is simply centrifuged into coarse powder and fine powder. However, the powder is crushed and the powder is supplied to the classification chamber. The airflow classifier also includes a crusher having a classifying function of classifying into coarse powder and fine powder.

[0027]

[Effect of device]

 As described above, in the airflow classifier according to the present invention, since the pressure in the flow passage can be measured by the pressure measuring device, when adjusting the classification point by adjusting the opening of the louver, the louver at the test stage is adjusted. It can be easily reproduced to an appropriate opening, and the classification point adjustment work is extremely easy.

The pressure measuring hole formed in the louver is included in the secondary air because it is in a state of opening along the surface of the louver facing the flow passage and following the flow of the secondary air flowing through the flow passage. The dust in the flow passage is hardly adhered, and the pressure in the flow passage can be measured very accurately, and the pressure can be measured without disturbing the flow of the secondary air.

Furthermore, since dust is not attached, it is not necessary to perform maintenance and inspection frequently.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of an air classifier according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the louver support portion of FIG.

3 is a cross-sectional plan view of FIG.

[Fig. 4] Flow sheet of a classification plant using an airflow classifier

[Explanation of symbols]

 3 Classification room 8 Louver 9 Flow passage 40 Pressure measuring hole 42 Pressure measuring instrument

Claims (1)

[Scope of utility model registration request] 1. A flow passage between adjacent louvers provided with a large number of louvers rotatably supported in the outer circumferential direction of a classification chamber to which a constant suction force is applied, at equal intervals, and adjusting the opening of each louver. In the air flow classifier in which the flow rate of the secondary air sucked into the classification chamber is changed to adjust the classification point of the powder centrifuged in the classification chamber, one of the louvers faces the flow passage. The air flow classifier is characterized in that a pressure measuring hole is formed on the surface to be formed, and the pressure measuring hole is provided with a pressure measuring device for detecting the pressure of the flow passage that changes due to the flow velocity fluctuation of the secondary air.