JPS60217982A - Detector for state of path of powdered and granular body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a detection device for detecting clogging of powder or granular material in a granular material path.

For example, in a device that takes out a desired amount of powder or granules from a storage hopper to a predetermined location by operating a valve or an inter-room supply device, a phototube type or mechanical type is installed inside the storage hopper. A level meter consisting of a switch is installed, and this level meter detects whether the inside of the storage hopper is empty.If the powder or granules are not supplied to the designated location even though it is not empty, a blockage occurs. I judged that.

However, in such conventional devices, when a level meter consisting of a phototube type switch is used, it may malfunction due to adhesion of dust, or if the powder or granule is transparent, accurate detection may be affected by its transparency. The problem was that I couldn't do it. Furthermore, when a level meter consisting of a mechanical switch is used, there is a problem in that it is prone to failure and lacks operational reliability.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to provide a powder path state detection device that can always accurately detect the state of a powder or granule material.

In order to achieve the above object, the state detection device for the route of powder or granular material according to the present invention includes a sensor section consisting of a pair of electrodes installed in the route of the powder or granule, and a signal corresponding to the capacitance between the pair of electrodes. The present invention is configured to include a detector that outputs , a differentiation circuit that differentiates the signal from the detector, and a determination that determines the state of the powder or granular material from the output signals of the detector and the differentiation circuit.

According to this configuration, conditions such as clogging of the powder or granular material are detected based on the capacitance between the pair of electrodes and its rate of change.
Accurate detection is always possible without being affected by the transparency of dust or powder. The state can be detected, for example, when powder or granular material is supplied from a storage potper, if the rate of change in capacitance is above a predetermined value, it is normal, and if the rate of change is zero or a value close to zero, the capacitance is If the capacitance corresponds to the dielectric constant of air, it can be determined that the storage hopper is empty, and if the capacitance corresponds to the dielectric constant of the powder, it can be determined that the storage hopper is clogged with powder.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Fig. 1 is a cross-sectional view of the main part of the powder/granular material path, where 1 is a storage hopper, 2 is a supply pipe connected to the storage hopper 1, and the powder/granular material in the storage hopper 1 is transported by a valve device (not shown). Alternatively, by driving a quantitative supply device, the liquid is supplied from the storage hopper 1 to a predetermined location through the supply pipe 2. At this time, the desired amount is supplied by the operation of a weighing device (not shown). On the inner circumferential surface of the supply pipe 2, a pair of electrodes 2a, 3b facing each other and a pair of electrodes 4a, 4b facing each other are installed at a predetermined interval in the axial direction. . If the supply pipe 2 is made of a conductive material, the supply pipe 2 and the electrodes 3a, 3b, 4a, 4b are insulated.

FIG. 2 is a circuit block diagram of a device for detecting the state of a powder path in an embodiment of the present invention, in which 5 is a detector using the electrodes 3a and 3b as a sensor section, and 6 is a sensor section using the electrodes 4a and 4b. The detector 5 outputs an electric signal according to the capacitance between the electrodes 3a and 3b, and the detector 6 outputs an electric signal according to the capacitance between the electrodes 4a and 3b.
Each outputs an electric signal according to the capacitance between the terminals 4b. Differentiating circuits 7 and 8 differentiate the output of the detector 5.6. Reference numeral 9 denotes a determination circuit that determines the state of the powder or granular material based on the outputs from the detectors 5, 6 and the differentiating circuits 7.8.

Next, the operation will be explained. When the valve device or drive device (not shown) is operated, the powder and granules in the storage hopper 1 are transferred to the supply pipe 2.
is supplied to a predetermined location.

That is, as the powder flows inside the supply pipe 2, the capacitances between the electrodes 3a and 3b and between 4a and 4b both change over time, and the outputs of the detectors 5 and 6 change accordingly. . Therefore, a constant voltage signal is output from the differentiating circuits 7 and 8, and the determination circuit 9 determines from this signal that the powder path is in a normal state.

On the other hand, when the storage hopper 1 is empty, the powder does not flow inside the supply pipe 2, and the powder and granules do not flow between the electrodes 3a and 3b and between the electrodes 4a.

Since air exists between 4b, the detectors 5 and 6 output a constant signal corresponding to the capacitance corresponding to the dielectric constant of the air, and the differentiator circuit 7.8 outputs a constant signal corresponding to the capacitance corresponding to the dielectric constant of the air. A signal with a voltage of zero or close to zero is output.

Furthermore, if the powder or granule path is clogged, the powder or granules will not flow through the supply pipe 2, so the output of the differentiator circuit 7.8 will be zero or a value close to it, as is the case when it is empty. Electrode 4
'a, 4b is clogged downstream, if electrodes 3a, 3
Since powder exists between b and between 4a and 4b, the detector 5.6 outputs a constant signal corresponding to the capacitance 1 corresponding to the dielectric constant of the powder. At this time, since the permittivity of the powder is much larger than that of air, the detector 5,
The output of 6 also increases accordingly. Also, the electrodes 3a, 3
If clogging with powder occurs between electrodes 4a and 4b, there is powder between electrodes 3a and 3b and air between electrodes 4a and 4b, so the output of detector 5.6 also It will be done accordingly.

Thus, in the case of an abnormal state, the output from the differentiating circuit 7.8 becomes zero or a voltage close to it, and the outputs of the detectors 5 and 6 are determined according to the abnormal state. A signal corresponding to the state is outputted to control, for example, the display device 10 or the quantitative supply device.

Note that in the above embodiment, the electrodes 3a face each other.

3b or 4a, 4b, but as shown in FIG.
.

A detector having a sensor portion such as 12b fixed thereto may also be used.

Further, in the above embodiment, the electrodes 3a and 3b are connected to the supply pipe 2.
Although this is installed inside the storage hopper 1, it may also be installed at the bottom of the storage hopper 1.

Further, in the above embodiment, two detectors 5°6 are used to determine whether clogging of powder or granular material occurs upstream or downstream of the electrodes 4a and 4b. ,
Only the detector 5 may be used, and even in this case, it is possible to discriminate between three states: normal, empty, and clogged. Additionally, three or more detectors can be installed to determine the location of the blockage in detail. In this case, the sky determination may be performed using only the first stage detector.

As explained above, according to the present invention, since the state of the powder path is detected based on the capacitance between the electrodes and its rate of change, accurate detection can be performed at all times without being affected by dust, etc. , it is possible to reduce the number of failures and extend the life of the detector.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main part of a powder/granular material route in which a powder/granular material route state detection device is installed in an embodiment of the present invention, and Fig. 2 is a circuit block diagram of the same powder/granule material route state detection device. , FIG. 3 is a side view of a sensor section in another embodiment of the present invention. 1- Storage Ml Hola t<-12-(It m tube, 3a
, 3b, 4a, 4b. 12a, 12b... Electrode, 5.6... Detector, 7
．． 8... Differential circuit, 9... Judgment circuit agent Yoshihiro Morimoto

Claims (1)

[Claims] 1. A detector in which a sensor section consisting of a pair of electrodes is installed in the path of the powder and granules and outputs a signal according to the capacitance between the pair of electrodes, and a differentiation circuit that differentiates the signal from this detector. and a determination circuit for determining the state of the powder or granule from the output signals of the detector and the differentiation circuit.