JPH0382919A - Weighing apparatus for powder, grain and the like - Google Patents

Abstract

PURPOSE:To make it possible to improve measuring accuracy by controlling an apparatus by driving a conveying device at a high speed at the initial feeding stage, gradually decreasing the speed before a preset constant measuring value and driving the conveying device, and then driving the conveying device at a very low speed. CONSTITUTION:When the start switch of an operating part 12 is turned ON, a microcomputer 11 outputs a first control signal. Thus the discharge quantity of the variable flow-rate pump of a hydraulic controller 20 is set at the maximum value. A hydraulic motor 4 is rotated at the maximum speed. A conveying device 3 is driven at the maximum speed. A large amount of powder and grains in a container 1 is supplied into a measuring container through a discharge port 2. The amount of supply is measured with a load cell 6 and inputted into a control device 10. When the measured value reaches a first value before determination, the device 10 outputs a second control signal, and the supplying amount of the powder and grains is decreased. When the measured value reaches the second value before determination, a third control signal is outputted, and the device 3 is driven at a speed of 1/n the maximum speed. When the measured value becomes the value obtained by subtracting the fall value from the preset value, a stop signal is subtracting the fall value from the preset value, a stop signal is outputted, and the device 3 is stopped. The supplying amount of the powder and grains becomes the value set by the fall amount.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a method for supplying powder or granules stored in a container to a measuring container while measuring a preset amount from the container using a conveying device. It relates to a measuring device for granules, etc.

(Prior Art) Conventionally, as shown in Fig. 5, a measuring device for powder or granular materials, etc., bypasses the discharge side of a constant displacement pump p to a tank C via a throttle valve a and an electromagnetic switching valve. By controlling the opening and closing of the electromagnetic switching valve s with the control device d based on the detection signal of the load cell g, the amount of oil supplied from the constant displacement pump p to the hydraulic motor e is controlled, thereby driving the hydraulic motor e. The drive of the conveyor f was controlled to supply a fixed amount of powder, etc. contained in the container to the measuring container i.

(Problem to be Solved by the Invention) However, in the conventional device described above, the rotation speed of the hydraulic motor e is changed by bypassing the discharge amount of the constant displacement pump p to the pump C, so a large amount of oil is pumped into the tank C. When bypass is used, the oil temperature rises due to oil passage resistance, which adversely affects the hydraulic system. Therefore, the hydraulic motor e
Because it was not possible to sufficiently control the amount of oil supplied to the container and drive the hydraulic motor e at low speed, it was difficult to supply a small amount of powder or granules to the measuring container l using the conveyor f, and the amount of oil supplied to the measuring container i It was difficult to accurately supply a fixed amount of powder or granules, and the measurement accuracy was poor.

(Means for Solving the Problems) A measuring device for powder and granular materials, etc. of the present invention includes a container for storing powder and granular materials, and a container for measuring powder and granular materials in the container. A conveying device that supplies oil from the outlet to the outside, a variable flow pump that supplies oil to a hydraulic motor that drives this conveying device, a measuring container provided below the outlet of the container, and a measuring container that is connected to the measuring container. and a control device that controls the discharge amount of the variable flow rate pump based on the detection signal of the weight detection device to supply a fixed amount of powder or granular material to the measuring container by the conveyance device, the control device The conveyor device is configured to be driven at high speed in the initial stage of supply, gradually decelerated before reaching a preset quantitative value, and then driven at a slow and constant speed.

(Function) By controlling the discharge amount of the variable flow rate pump and controlling the rotation of the hydraulic motor using a control signal output from the control device, a fixed amount of powder is supplied by the conveying device driven by the hydraulic motor. When supplying a fixed amount of powder or granular material, the control device drives the conveying device at high speed in the initial stage of supply, gradually decelerates it before reaching a preset value, and then drives it at a slow and constant speed. We aim to improve weighing accuracy by controlling the

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of a powder/grain material measuring device according to the present invention.

In the figure, reference numeral 1 denotes a container such as a tank or a silo for storing powder and granular material, and a discharge port 2 is formed at one longitudinal end of the bottom surface of the container 1. A conveying device 3 is disposed at the bottom of the container 1 in the longitudinal direction. As the conveyance device 3,
A screw conveyor or a belt conveyor as shown in the figure is used, and this conveying device 3 is driven by a hydraulic motor 4, and by this drive, the powder and granules in the container 1 are discharged from the discharge port 2. is being done. The rotation of the hydraulic motor 4 is controlled by a hydraulic control word 220, which will be described later.

Further, below the discharge port 2 of the container 1, a measuring container 5 for storing the powder discharged from the discharge port 2 is provided. The weighing container 5 is provided with a load cell 6 (weight detection means) for measuring the weight of the powder or granular material supplied to the weighing container 5.

10 is a control device, and this control device 10 is a load cell 6.
The measured weight signal is input manually, and each control signal is output to the hydraulic control device 20.

As shown in FIG. 2, the hydraulic control device 20 includes a variable flow rate pump 21 with pressure compensation and an electromagnetic variable throttle valve 22 connected to the variable flow rate pump 21. The electromagnetic variable throttle valve 22 controls the discharge amount of the variable flow rate pump 21 based on a control signal from the control device O, thereby controlling the rotation of the hydraulic motor 4. 23 is a switching valve.

The control device 10 includes a microcomputer 11 and an operation section 1.
2, weighing amplifier 13, digital/analog converter 14,
It is equipped with an amplifier 15 for an electromagnetic variable throttle valve. The microcomputer 11 receives a weight signal measured by the load cell 6 via a weighing amplifier 13, and also receives an operation signal input from the operating section 12. The operation signals include a setting signal for setting the amount of rice granules to be supplied to the measuring container 5, a start switch signal, and the like. Then, the microcomputer 11 transmits each control signal based on these weight signals and operation signals to the hydraulic control device 2 via a digital/analog converter 14 and an amplifier 15 for an electromagnetic variable throttle valve.
0 to the electromagnetic variable throttle valve 22. As a result, the electromagnetic variable throttle valve 22 operates according to each of these control signals to control the discharge amount of the variable flow rate pump 21. Specifically, the following four control signals are mainly output from the control device. ■ A primary control signal that maximizes the discharge amount of the variable flow rate pump 21 and increases the driving speed of the conveying device 3; ■ Gradually decreases the discharge amount of the variable flow pump 21 and gradually increases the driving speed of the conveying device 3. Secondary control signal for deceleration, ■Variable flow pump 21
A tertiary control signal that further reduces the discharge amount of the transport bag W3 and drives it at a constant speed of 1/n of the maximum speed (n: integer); Stop signal to zero.

Here, when the granular material is supplied by the transport device 3, even if the transport device 3 is stopped, some of the granular material falls from the storage container 1 into the measuring container 5 due to inertia, which is a so-called head difference. .

Therefore, this amount of head difference is input in advance to the microcomputer 11 of the control device 10 via the operation unit 12 as a head value. This head value is determined by the driving speed of the transport bag W3 before it stops. Since the driving speed of the conveying device 3 before it stops is determined in advance by the tertiary control signal, the head value is also determined at the same time. The operation of the weighing device will be explained with reference to the flowchart of FIG.

First, set the measured quantitative value of the powder and granular material to be supplied from the storage container 1 to the measuring container 5, enter this set value manually into the operating section 12, and turn on the start switch of the operating section 12.
A setting signal and a start signal are output from the operating section 12 to the microcomputer 11.

The microcomputer 11 outputs a primary control signal to the electromagnetic variable throttle valve 22 based on the start signal.

As a result, the discharge amount of the variable flow rate pump 21 is maximized, the hydraulic motor 4 is rotated at the highest speed, and the transfer device (conveyor)
3 at maximum speed. As a result, a large amount of the powder in the container 1 is supplied from the outlet 2 to the weighing container 5 (rough weighing). This amount of supply is measured as weight by the load cell 6, and this weight signal is manually input to the control device 10. When the measured value reaches a preset first pre-quantification value, the control device 10 outputs a secondary control signal to the electromagnetic variable throttle valve 22 to gradually reduce the discharge amount of the variable flow rate pump 21 and transport the fluid. The drive of the device 3 is gradually decelerated to gradually reduce the amount of powder and granular material supplied (first fine metering). Furthermore, the load cell 6 continues to measure the amount of powder and granular material supplied.
When this measured value reaches the second pre-quantification value, the control device 10 outputs a tertiary control signal to the electromagnetic variable throttle valve 22 to further reduce the discharge amount of the variable flow rate pump 21.
is driven at a constant speed of 1/n of the maximum speed (second fine metering). Next, when the measured value measured by the load cell 6 reaches a value obtained by subtracting the amount of head from the set value (set value head (i)), the control device 10 outputs a stop signal to the electromagnetic variable throttle valve 22, and the variable flow pump 21 is set to zero and the driving of the conveying device 3 is stopped.By stopping the conveying device 3 in this way, the supply of powder and granular material is completed, but the powder and granular material is still weighed as a head amount. A small amount of powder is supplied to the container 5, and as a result, the powder and granular material in the measuring container 5 reaches a preset supply amount (metering fixed value), which is the amount until the conveying device 3 is stopped and the amount of head difference.

FIG. 4 shows the relationship between time and amount supplied by the metering device of the present invention and the conventional metering device. In FIG. 4, the solid line shows the relationship between time and supply amount in the measuring device of the present invention, and the broken line shows the relationship in the conventional measuring device. As shown in Figure 4, the conventional weighing device is
3 cannot be sufficiently decelerated and the control is rough, so the first fine metering must be started at an earlier point in time than the metering device of the present invention. Furthermore, in the conventional weighing device, the amount of head difference after the completion of the second micrometering is large, and the supply time is long, resulting in a large error.

Note that the first quantitative value and the second quantitative value are, for example, 7 of the set value.
The weight ratio may be preset with respect to the set value such that 0% is the first quantitative value and 90% of the set value is the second quantitative value.

Further, the measuring device of the present invention can be used not only for powdery materials but also for, for example, sand, gravel, ready-mixed concrete, and the like.

Furthermore, although a single weighing container 5 was used in this embodiment, if a plurality of weighing containers are provided and one weighing container is immediately switched to another weighing container when it is full, the efficiency of weighing work can be improved. can be achieved.

(Effects of the Invention) As described above, according to the present invention, by controlling the discharge amount of the variable flow rate pump by the control device, the conveyance device is driven at high speed in the initial stage of supply, and the preset setting is controlled. By controlling the device to gradually decelerate before reaching the specified value and then drive at a very slow and constant speed, it is possible to improve measurement accuracy and to supply powder and granules to the weighing container accurately and quickly. I can do it.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a schematic configuration of a powder/granular material measuring device according to the present invention, Fig. 2 is a hydraulic circuit diagram showing a hydraulic control device, and Fig. 3 explains the operation of the powder/granular material measuring device. Flowchart diagram, FIG. 4 is a diagram showing the relationship between time and supply amount by the powder and granule measuring device of the present invention and the conventional powder and granule weighing device,
FIG. 5 is a block diagram showing the structure of a conventional rice granule measuring device. ■...Container 2...Discharge port 3...Transport device W 4...Hydraulic motor 5...Weighing container 6...Load cell (weight detection means) 10...Control device 21...・Variable flow pump

Claims (1)

[Scope of Claims] 1) A container for storing powder, granules, etc., a transport device for supplying the powder, granules, etc. in this container to the outside from a discharge port formed in the container, and this transport device. a variable flow pump that supplies oil to a hydraulic motor that drives the container, a measuring container provided below the outlet of the container, a weight detecting means connected to the measuring container, and a detection signal of the weight detecting means. and a control device that controls the discharge amount of the variable flow rate pump based on the flow rate to supply a fixed amount of powder or granules to the measuring container by the conveyance device, and the control device controls the conveyance device at high speed in the initial stage of supply. What is claimed is: 1. A measuring device for measuring powder or granular materials, characterized in that the device is configured to be driven, gradually decelerated before a preset quantitative measurement value, and further driven at a very slow and constant speed.