JPH01180422A - Powder level measuring instrument - Google Patents

Abstract

PURPOSE:To simplify the device and to decrease the number of wires greatly by providing a signal generating device which is independent of a machine device for weight elevation and generates an electric signal line a pulse signal, etc., independently and a controller which puts a motor in reversible motion. CONSTITUTION:The machine device 92 for weight elevation consists of a two- phase reversible motor 1, a powder level detection switch 3, and an upper-limit switch 4 which operates when a weight reaches its upper elevation limit, and the signal generating device 72, a counter type display device 76, etc., are arranged independently of said device 92. The device 72 starts outputting a pulse signal a proper predetermined time later at the start of operation and the device 76 breaks its internal electric contact 9 when a counted value reaches a numeral corresponding to the preset lower-limit position of the weight. A current detector 80 makes electric contacts 81-83 while a current flows to the motor 1. Consequently, the output of the signal is started by the device 72 the proper predetermined time later to correct a measurement error generated at the actuation of the motor 1, and the device 46 counts the generated pulse signal to display the storage level of powder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a weight-type powder level measuring device for measuring the storage level of powdery and granular materials stored in tanks, silos, and the like.

[Conventional technology]

Conventionally, the above-mentioned powder level measuring device has been equipped with a mechanism that uses a motor to raise and lower a weight suspended from a rope, etc., as well as an upper limit switch, a powder surface detection switch, and a lower limit switch that control the lifting distance of the weight. A position transmitting device such as a variable resistor, a synchro electric machine, or a pulse transmitter is installed inside the provided mechanical device, and the position transmitting device is connected to a mechanical shaft connected to the rotating shaft of the motor to control the descending movement of the weight. A known structure is known in which a powder storage level signal is output when a powder level detection switch or a lower limit switch is activated and the descending movement of the weight is stopped.

Therefore, to explain the powder level measuring device according to the conventional example shown in FIG. The signal from the pulse signal generator 71 corresponding to the powder storage level is counted and displayed by a counter type display device 75, where 2 is a difference capacitor and 3 is a heavy duty capacitor. Powder surface detection switch that operates when the weight lands on the powder storage surface;
Reference numerals 4 and 5 denote an upper limit switch and a lower limit switch which operate at the limit of lifting and lowering the weight, respectively, and these constitute a mechanical device 91 for lifting and lowering the weight.

[Problem that the invention seeks to solve]

However, the weight type powder level measuring device as mentioned above is
Since the descending distance of the weight is detected by the rotation angle of the position transmitter connected to the mechanical shaft connected to the motor shaft, the mechanism of the mechanical device for raising and lowering the weight becomes complicated, increasing the manufacturing cost of the powder level measuring device. This also had the disadvantage of making maintenance difficult.

In addition, the powder level measuring device as described above is installed between the mechanical device for lifting and lowering the weight, which is installed on the top of the powder storage tank or Sakiiro, and the electrical room or central control room that controls the powder storage tank. A large amount of wiring is required for power, control, and signals, and when outputting measured values as DC signals, special wires such as shielded wires may be used, which requires a large amount of wiring costs. This was a factor that significantly increased the cost of equipment for measuring powder levels.

The present invention has been made in consideration of the above-mentioned circumstances, and by changing the method of generating the storage level signal and the control method of the motor for lifting and lowering the weight, it is possible to The object of the present invention is to provide a powder level measuring device that can simplify the mechanical device and drastically reduce the number of wiring between the mechanical device and the control room.

[Means for solving problems]

A powder level measuring device according to the present invention that achieves the above object uses a motor to lower a weight suspended from a rope, and measures the amount of powder by the distance the weight falls when it reaches the powder storage surface. This is a weight-type powder level measuring device that measures the storage level, and is equipped with a mechanism that uses a motor to raise and lower a weight suspended from a rope, etc., as well as an upper limit switch that limits the lifting distance of the weight, a powder level detection switch, etc. a mechanical device provided therein; a signal generating device that is independent of the mechanical device and can independently generate an electrical signal such as a pulse signal, a voltage signal, or a current signal;
and a control device that performs reversible operation of the motor, and determines whether power is being supplied to the motor by a signal from the control device or a signal from a current or voltage detector connected to the circuit of the motor. , the signal generating device is operated only while power is being supplied to the motor to obtain an electric signal corresponding to the descending distance of the weight (Example) Next, referring to the attached drawings, , an example embodying the present invention will be explained to provide an understanding of the present invention.

Here, FIG. 1 is a connection diagram showing an embodiment of the powder level measuring device of the present invention.

In Fig. 1, 1 is a motor for lifting and lowering a weight, in this case a two-phase reversible motor equipped with a capacitor 2 for difference, and 3
4 is a powder surface detection switch that is activated when the weight lands on the powder storage surface, 4 is an upper limit switch that is activated when the weight reaches its maximum rise, and 1 to 4 above are mechanical devices 92 for lifting and lowering the weight. It is an electrical component that makes up the 10 and 20 are relays for lowering and lifting the weight, and 1112.13 and 21.22.23 are electrical contacts of the relays 10 and 20, respectively. 30
is a timer, and 31 is an electrical contact of the timer 30, which is configured to become conductive in about one second after the timer 30 is energized. 40 and 50 are relays, and 41 and 51 are electrical contacts of the relays 40 and 50, respectively. Reference numeral 72 denotes a signal generator that generates a pulse signal at an appropriate period, and the signal generator W72 is configured to start outputting a signal after a predetermined appropriate time delay at the start of operation. 76 is a counter type display device in which the built-in electric contact 9 becomes non-conductive when the counted value reaches a value corresponding to the lower limit position of the weight set in advance;
is a current detector that makes electrical contacts 81, 82, and 83 conductive only during the period when current is flowing through motor l.

To explain the operation in this embodiment, when the measurement switch 6 is pressed, the weight lowering relay IO is energized, the electrical contact 11 becomes disconnected, and at the same time, 12 and 13 become conductive, and the motor l lowers the weight. Rotate in the direction. At the same time, current detector 80 is activated, electrical contacts 81, 82, and 83 are brought into conduction, relay 40 is energized, and electrical contact 41 is brought into conduction. When the weight lands on the powder storage surface or descends to the lower limit position, the powder surface detection switch 3 or the electrical contact 9 becomes non-conductive, the motor 1 stops, and the electrical contacts 81, 82, . 83 also becomes non-conductive and the relay IO is deenergized. When the relay lO is de-energized, the electrical contact 11 becomes conductive and the timer 30 is energized. About one second later, the electrical contact 31 becomes conductive and the relay 20 is energized, and the electric contact 22 causes the motor l to move in the direction of lifting the weight. Rotate.

At the same time, the electrical contacts 81, 82, 83 of the current detector 80 become conductive again, the relay 50 is energized, the electrical contact 51 becomes non-conductive, and the relay 40 is deenergized.

When the weight rises to the upper limit position, the upper limit switch 4 becomes non-conductive, the motor 1 stops, and the electrical contacts 81, 82, 83 of the current detector 80 also become non-conductive, and the relays 20 and 50 are deenergized. On the other hand, the signal generator 72 resets the counter type display device 76 at the moment the weight lowering relay 10 is energized and the electrical contact 13 becomes conductive, and also
A pulse signal is generated at an appropriate cycle only during the period when 3 is conductive. At this time, the signal generator 72 is activated in advance.
The output of the signal is started after a delay of a predetermined appropriate time to correct measurement errors that occur mainly when starting the motor l. Further, the pulse signal generated by the signal generator 72 is counted by the display device 76 and displayed as the storage level of the powder.

In this embodiment, when the power supply frequency is 50Hz, the weight is raised and lowered at a speed of 1QOt@/second, and the signal generator 12 uses a pulsating current obtained by full-wave rectification of the AC power source as a signal source at a cycle of 1/100 seconds. By configuring the pulse signal to be generated in such a way that it is possible to measure the powder level with an accuracy of 1 pulse per 1 pulse, the circuit configuration of the signal generator 72 is simplified and the manufacturing cost of the level tunnel device can be reduced. Furthermore, in this embodiment, the counter type display device 76 is configured to output a digital signal, and the output signal is
If configured to perform A conversion, it is possible to easily obtain a current or voltage signal, which can be used for powder storage tank control.

In the above embodiments, a case has been described in which a contact relay is used as the control device, but the present invention is also applicable to a case where a non-contact relay consisting of a logic circuit or an IC circuit developed from the non-contact relay is used.

〔Effect of the invention〕

Since the present invention is configured as described above, it simplifies the structure of the powder level measuring device, greatly reduces manufacturing costs, and facilitates maintenance, and also controls the mechanical device for lifting and lowering the weight and the storage tank for the powder. This has the effect of significantly reducing the number of wires between electrical rooms or central control rooms and reducing equipment costs. Further, since there is no need to provide a signal generating device inside the mechanical device chamber for lifting and lowering the weight, there is no need for wiring of signal lines, and there is an advantage that a powder level measuring device can be constructed that is completely unaffected by induced noise.

[Brief explanation of the drawing]

Fig. 1 is a connection diagram showing an embodiment of the present invention, and Fig. 2 is a connection diagram showing a conventional powder level measuring device.・・・－・・・
Gondo capacitor, 3-・・・・・・Powder surface detection switch, 4・・・・−・− Upper limit switch, 5−・・・・・・・
-Lower limit switch, 6-...Measurement switch, 7...
...-AC electrical wiring, 8 ...--DC electrical wiring, 10.20.40.50 ...-Relay, 11-1
3.21-23.31.41.51.8L82.83-
・-・Electrical contact, 71-・-・・・Pulse signal generator, 72-・・・・Signal generator, 75 ・・
...-Counter type display device, 76 ...--Counter type display device, 80---Current detector, 91.
92 ・・・−・Representative of a machine for lifting and lowering weights Patent attorney Chubu Fujio Diagram 1 Diagram 2 procedural amendment (voluntary)

Claims (4)

[Claims] (1) A weight type powder level measuring device that uses a motor to lower a weight suspended from a rope and measures the storage level of powder by the distance the weight descends when it reaches the powder storage surface. A mechanical device that is equipped with a mechanism for raising and lowering a weight suspended by a rope or the like using a motor, and also equipped with an upper limit switch that limits the lifting distance of the weight, a powder surface detection switch, etc., and a mechanical device that is independent of the mechanical device. A signal generating device capable of independently generating an electric signal such as a pulse signal, a voltage signal, or a current signal, and a control device that performs reversible operation of the motor, and determines whether power is being supplied to the motor. The signal generating device is operated only while power is being supplied to the motor by a signal from the control device or a signal from a current or voltage detector connected to the circuit of the motor, and an electric signal corresponding to the descending distance of the weight is generated. A powder level measuring device characterized in that it obtains the following: (2) A control device that performs reversible operation of the motor for lifting and lowering the weight,
2. The powder level measuring device according to claim 1, wherein the operation of an upper limit switch, a powder level detection switch, etc. connected to the motor is detected by a change in current in the motor circuit. (3) The powder level measuring device according to claim 1 or 2, wherein the signal generator generates a pulse signal at an appropriate period using an AC power source as a signal source. (4) The powder according to claim 1, 2, or 3, wherein the signal generator starts outputting the signal after a delay of an appropriate predetermined time. Level measuring device.