JP7805728B2 - Recycled material metering device and metering method - Google Patents

Description

The present invention relates to a weighing device and method for recycled materials that have been thermally recycled in a recycling dryer.

At asphalt plants, in order to reuse asphalt pavement waste (hereinafter referred to as "waste") dug up during road construction and other work, the waste blocks are crushed to a specified particle size, and then recycled by heating to a specified temperature in a recycling dryer. This recycled material is then mixed in a mixer with new aggregate that has been separately heated in a new material dryer to the desired ratio, producing the desired asphalt mixture.

During plant operation, the heated recycled material is stored in a recycled material storage bin, and when producing asphalt mixture, a pair of double-wing gates, consisting of a left and right gate attached to the discharge outlet at the bottom of the recycled material storage bin, are controlled to open and close, and an appropriate amount of recycled material is dispensed into a recycled material measuring tank below, thereby measuring the appropriate amount according to the blend (Patent Document 1).

However, since it is difficult to store recycled materials stored in the recycled material storage bin for long periods of time due to quality issues such as temperature drop, when the plant finishes operating, both left and right gates of the double-door gate are fully opened and all recycled materials in the recycled material storage bin are removed in preparation for the next operation.

JP 2017-198041 A

However, the double-swing gate of the above-mentioned conventional device is designed to control the left and right gates in conjunction with each other to maintain the same opening angle using a link mechanism, and is not designed to be controlled to open and close independently.

In particular, when controlling the opening and closing of the gates when measuring recycled materials, in order to prevent the target measurement value from being exceeded, the left and right gates are not opened fully, but are both kept half-open to narrow the opening area of the discharge outlet. This reduces the discharge speed when dispensing recycled materials from the recycled material storage bin to the recycled material measuring tank, ensuring measurement accuracy.

As a result, when the plant is operating, recycled material discharged from the recycled material storage bin tends to be concentrated near the center of the discharge outlet, and near the periphery of the discharge outlet, discharge is blocked by the half-open gate, which tends to cause recycled material to remain stagnant for long periods of time, creating what is known as dead space.

As a result, recycled materials tend to adhere to the inner walls at the bottom of the recycled material storage bin, and some kind of improvement is desirable.

If the accumulation of recycled material is due to the gate being half-open, it is expected that sufficient weighing accuracy can be ensured even if both the left and right gates are fully open during weighing by, for example, making the discharge outlet smaller in diameter. However, in this case, it would take a long time to remove the recycled material at the end of operation, making it less convenient to use, so it is considered difficult to adopt this method.

In view of the above, the present invention aims to provide a recycled material weighing device and weighing method that can suppress the adhesion of recycled material while ensuring weighing accuracy.

In order to solve the above problem, the recycled material weighing device described in claim 1 of the present invention is a recycled material weighing device comprising a recycled material storage bin with a double-door gate, a recycled material weighing tank below the recycled material storage bin for weighing recycled material, and a weighing controller that controls the opening and closing of the double-door gate so as to achieve a set weighing value. The weighing controller further comprises an individual opening/closing control unit that allows the double-door gates to be opened and closed individually, and when metering recycled material, one of the double-door gates is fully closed and only the other gate is fully opened to dispense the recycled material into the recycled material weighing tank.

Furthermore, the recycled material weighing method described in claim 2 is a method for controlling the opening and closing of double-door gates of a recycled material storage bin to dispense recycled material into a lower-level measuring tank, characterized in that when measuring recycled material, one of the double-door gates is fully closed and the other gate is fully opened, and recycled material is dispensed so that the weight of the measuring tank reaches a set measurement value.

According to the recycled material metering device of claim 1 of the present invention, the metering controller is equipped with an individual opening/closing control unit that allows the double-door gates to be opened and closed individually. When metering recycled material, one of the double-door gates is fully closed and the other gate is fully opened to dispense the recycled material into the recycled material metering tank. This allows the opening area of the discharge outlet to be narrowed, while the recycled material near the lower inner wall of the recycled material storage bin can be discharged sequentially without being retained for long periods of time. As a result, adhesion of recycled material can be suppressed while maintaining metering accuracy.

Furthermore, according to the recycled material weighing method described in claim 2, when weighing recycled material, one of the double-door gates is fully closed and the other gate is fully opened, and recycled material is dispensed so that the weight of the weighing tank reaches the set weighing value.This means that even while narrowing the opening area of the discharge outlet, recycled material can be discharged sequentially without being retained near the lower inner wall of the recycled material storage bin for long periods of time, thereby ensuring weighing accuracy while suppressing adhesion of recycled material.

1 is a schematic explanatory diagram of a recycled material metering device according to the present invention. 1A and 1B are a front view and a bottom view of the lower part of the device when the left gate is fully closed and the right gate is fully open. 1A and 1B are a front view and a bottom view of the lower part of the device when the right gate is fully closed and the left gate is fully open. 1 is a flowchart of a method for measuring recycled materials according to the present invention.

The recycled material metering device of the present invention comprises a recycled material storage bin equipped with a double-door gate, a recycled material metering tank for metering recycled material located below the recycled material storage bin, and a metering controller that controls the opening and closing of the double-door gate so that a set metered value is achieved. The metering controller further comprises an individual opening/closing control unit that allows the left and right gates of the double-door gate to be opened and closed independently.

The weighing controller further includes a setting unit that stores modes, such as "weighing mode" and "extraction mode."

When the recycled material is being weighed during plant operation, the "weighing mode" is selected, and the individual opening/closing control unit fully closes one of the double-door gates while fully opening the other gate, and dispenses and weighs the recycled material so that the weight of the weighing tank reaches the set weighing value.

At this time, by fully closing one of the gates, the opening area of the discharge outlet is narrowed to about half of the entire discharge outlet, which allows the discharge speed of the recycled material to be moderately suppressed and ensures weighing accuracy.On the other hand, at the discharge outlet on the side where the gate is fully open, the recycled material can be discharged while flowing down along the inner wall surface, which is expected to reduce adhesion.

Preferably, the gate that is fully opened when measuring recycled material should be alternately switched from left to right at the desired timing, for example, for each batch. By alternately switching the gate from left to right to fully open, recycled material near the lower inner wall of the recycled material storage bin can be discharged evenly on both sides, which is expected to further improve the adhesion prevention effect.

On the other hand, when the plant finishes operating, "extraction mode" is selected, and the individual opening/closing control unit fully opens both gates to quickly extract the recycled material from the recycled material storage bin in preparation for the next operation.

In this way, with the recycled material weighing device and weighing method of the present invention, during weighing, rather than controlling both gates in conjunction to half-open simultaneously as in conventional devices, the left and right gates are controlled individually to alternately fully open and fully close one side at a time.

This minimizes the dead space around the edge of the discharge outlet, which can cause recycled materials to remain for long periods of time, while narrowing the opening area to the same level as conventional devices, which is expected to ensure both metering accuracy and the effect of suppressing adhesion of recycled materials.

An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 is a schematic diagram showing one embodiment of a recycled material metering device 1 according to the present invention, which mainly comprises a recycled material storage bin 2 for storing recycled material, a recycled material metering tank 3 located below the recycled material storage bin 2, and a metering controller 4.

The recycled material storage bin 2 has a discharge outlet 5 at the bottom end of its inverted cone-shaped body, which is equipped with a double-door gate 6. The double-door gate 6 is made up of a pair of roughly fan-shaped left and right gates 6a, 6b, each of which is further equipped with air cylinders 7a, 7b as drive means so that the left and right gates 6a, 6b can be opened and closed individually.

The recycled material weighing tank 3 further includes a load cell 8 that suspends and weighs the recycled material weighing tank 3, and a discharge gate 9 that discharges the recycled material from the recycled material weighing tank 3, for example, to a downstream mixer (not shown).

The left and right gates 6a, 6b of the double-swing gate 6 are pivotally supported by pivots 10a, 10b above the discharge port 5 and are connected to the air cylinders 7a, 7b with link members or the like. Meanwhile, on-off valves (not shown) are provided in the air pressure circuits (not shown) that supply operating air to the air cylinders 7a, 7b, allowing the air cylinders 7a, 7b to be driven individually, thereby enabling the left and right gates 6a, 6b to be opened and closed individually.

The weighing controller 4 comprises a main control unit 11 that controls the various units described below; an individual opening/closing control unit 12 that controls the opening and closing of the left and right gates 6a, 6b individually by controlling the drive of the air cylinders 7a, 7b; a calculation unit 13 that receives weight signals from the load cell 8 and performs weighing calculations; and a setting unit 14, which stores the "weighing mode" and "extraction mode" modes.

The "weighing mode" is the mode selected when weighing recycled materials, in which either one of the left or right gates 6a, 6b remains fully closed, while only the other gate is selected for opening and closing control.

In other words, when weighing recycled materials, "weighing mode" is selected, and the individual opening/closing control unit 12 fully closes any one of the double-swing gates 6, for example, gate 6b (or gate 6a), while fully opening only gate 6a (or gate 6b), which is selected as the other gate to be controlled, to perform weighing.

As shown in Figures 2 and 3, when gate 6b is fully closed and only gate 6a, which is subject to opening and closing control, is fully opened (Figure 2), and when gate 6a is fully closed and only gate 6b, which is subject to opening and closing control, is fully opened (Figure 3), the opening position of discharge outlet 5 is switched between left and right.

In this way, by alternating the left and right halves of the entire opening of the discharge outlet 5, it is possible to achieve discharge capacity comparable to that of conventional devices, which originally reduced the opening area to about half during metering, while eliminating the so-called dead space that occurs around the periphery of the discharge outlet 5, which is expected to have an effect of suppressing adhesion of recycled material to the inner wall surface around the periphery of the discharge outlet 5.

On the other hand, the "extraction mode" is a mode selected when extracting recycled materials. By fully opening both gates 6a and 6b of the double-opening gate 6 at the same time, recycled materials can be discharged from the entire discharge outlet 5 without being obstructed by the gates 6a and 6b.

In other words, when the plant finishes operating, "extraction mode" is selected, and the individual opening/closing control unit 12 fully opens both the left and right gates 6a and 6b to quickly extract recycled material and prepare for the next operation.

Next, a method for measuring recycled materials using the recycled material measuring device 1 according to the present invention will be described with reference to the flowchart shown in Figure 4. Note that S1 to S13 in Figure 4 represent each step.

When the asphalt plant is operating, prior to dispensing recycled material from the recycled material storage bin 2, the main control unit 11 of the metering controller 4 determines whether the setting unit 14 is in "metering mode" (S1). If it is in "metering mode," the main control unit 11 reads this and selects gate 6a (or gate 6b) as the gate to be initially controlled to open and close (S2), while fixing the other gate 6b (or gate 6a) in a fully closed state (S3). The following example describes the case where gate 6a is selected as the gate to be initially controlled to open and close.

Next, the measured weight of the recycled material is set according to the mix required to produce the asphalt mixture (S4), and the individual opening/closing control unit 12 fully opens only the gate 6a that is the target of opening/closing control (S5), and the recycled material is dispensed from the recycled material storage bin 2 into the recycled material measuring tank 3 to be weighed.

Then, the system waits for the set weighing value to be reached (S6), and when the calculation unit 13 determines that the weight of the weighing tank has reached the specified weighing value, it closes both the left and right gates 6a and 6b (S7), completing the weighing, and then checks whether plant operation has ended (S8).

If operation is not terminated in S8 (operation is to continue), the gate to be controlled for opening and closing is switched from gate 6a to gate 6b (S9), and the operations of S3 to S9 are then repeated until plant operation is terminated.

On the other hand, if plant operation is to be terminated in S8, the system switches to "extraction mode" (S10), the main control unit 11 fully opens both the left and right gates 6a and 6b (S11), and continues to dispense recycled material into the recycled material metering tank 3 until the recycled material storage bin 2 is empty.

The system then waits for extraction to be completed (S12), and once extraction is complete, both left and right gates 6a, 6b are closed (S13), and plant operation is terminated. The calculation unit 13 determines when extraction is complete, for example, when the recycled material storage bin 2 is empty, such as when there is no longer any weight fluctuation in the recycled material weighing tank 3. The extracted recycled material is then sequentially discharged from the discharge gate 9 of the recycled material weighing tank 3.

The timing of switching the gate to be controlled to open or close can be every batch or every few batches, or it can be switched multiple times within one batch weighing cycle.

It goes without saying that the above embodiment can be modified in various ways without departing from the spirit and scope of the present invention. For example, various actuators that operate on fluid pressure, such as hydraulic pressure, may be used in place of the air cylinders 7a and 7b.

Furthermore, the present invention can be relatively easily adapted to existing plant equipment with minimal changes to the control mechanism, etc., which has the advantage of keeping costs down and making it easy to adopt.

This invention can be widely applied to a wide range of equipment associated with asphalt plants, including recycled material storage bins for storing recycled material heated in a recycling dryer, as well as mixture silos for temporarily storing asphalt mixtures produced by mixing recycled material with new aggregate, and satellite silos, which are intermediate storage facilities.

DESCRIPTION OF SYMBOLS 1...Recycled material metering device 2...Recycled material storage bin 3...Recycled material metering tank 4...Measuring controller 5...Discharge outlet 6...Double-opening gate 6a, 6b...Gate 7a, 7b...Air cylinder 8...Load cell 9...Discharge gate 10a, 10b...Pivot 11...Main control unit 12...Individual opening/closing control unit 13...Calculation unit 14...Setting unit

Claims (2)

A recycled material weighing device comprising a recycled material storage bin with a pair of left and right double-swing gates, a recycled material weighing tank below the recycled material storage bin for weighing recycled material, and a weighing controller that controls the opening and closing of the double-swing gates so as to achieve a set weighing value, wherein the weighing controller further comprises an individual opening/closing control unit that allows the double-swing gates to be opened and closed individually, and when metering recycled material, one of the double-swing gates is fixed in a fully closed state , and only the other gate that is not fixed in a fully closed state and is subject to opening and closing control is fully opened so that the recycled material is dispensed into the recycled material metering tank, and the gate that is subject to opening and closing control is switched every batch or every few batches . A recycled material weighing method in which a pair of double-opening gates on the left and right of a recycled material storage bin are controlled to open and close to dispense recycled material into a lower-level measuring tank, characterized in that when measuring recycled material, one of the double-opening gates is fixed in a fully closed state and only the other gate that is not fixed in a fully closed state and is subject to opening and closing control is fully opened, recycled material is dispensed so that the weight of the measuring tank reaches a set measuring value , and after the set measuring value is reached, the gate that is subject to opening and closing control is switched .