JP7310619B2 - How to operate the dust remover - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of operating a dust remover equipped with a rotary screen frame for collecting dust from fluids such as seawater and river water.

2. Description of the Related Art At a plant facility such as a power plant where industrial water is used, a dust remover is installed in a channel for taking in cooling water or industrial water. This dust remover functions to remove foreign objects such as jellyfish and debris that flow into water intakes such as seas, rivers, and ponds. A simple dust remover is installed with a screen or wire mesh perpendicular to the direction of water flow or inclined at a predetermined angle. In addition, in power plants with a large amount of water intake, a structure is adopted in which dust can be removed without clogging by continuously catching dust by rotating the screen of the rotary mesh frame.

FIG. 5 is a perspective view of the dust remover. As shown in the figure, the dust remover 1 includes a pair of left and right (also referred to as width direction) carrying chains 2 provided to cross the water channel, and upper and lower sprocket wheels 3B for rotating the carrying chains 2 (the upper sprocket wheel is not shown). ) and a mesh frame 4 having a screen which is perpendicular to the water flow direction or inclined at a predetermined angle for each link of the carrying chain 2 .

In such a dust remover, when debris such as jellyfish suddenly attacks, the rotation speed of the mesh frame is increased to quickly rake up the debris, thereby reducing the debris on the upstream side and reducing the flow resistance on the upstream and downstream sides as much as possible. less. At this time, the determination to change the operating speed is made by measuring the water level on the upstream side and the downstream side, and changing the operating speed when the difference (water level difference) exceeds a predetermined value (disclosed in Patent Documents 1 to 4). The dust remover of 1 performs rotation control based on the water level measurement values on the upstream and downstream sides.). As an example, operation is started when the water level difference reaches 200 mm, and switching to high speed operation occurs when the water level difference reaches 350 mm or more (two-step operation management).

When a large amount of jellyfish flow into the water intake channel, the jellyfish reach the dust removal device together with the running water of the water channel. When a large amount of jellyfish adheres to the screen of the dust remover, it immediately spreads on the surface of the net due to water pressure, widening the shielding area and almost completely blocking the running water, causing a sudden difference in water level between the upstream side and the downstream side of the dust remover.

As an example, cooling water from a power plant or the like that flows into a waterway normally flows through the waterway at a speed of about 0.3 m/s. The upstream and downstream water level gauges of the dust remover are installed several meters upstream and downstream of the dust remover (for example, approximately 2 meters in front of and behind the dust remover) to measure the respective water levels. Depending on the size of the difference, the amount of debris such as jellyfish is determined, and the operating speed of the dust remover is changed. In such a method of determining and changing the operating speed from the measurement result of the water level difference, collection of a large amount of debris such as jellyfish is delayed, and in the worst case, it is necessary to consider reducing the cooling water.

Here, the size of the water channel in which the power plant cooling water dust remover is installed varies depending on the installation location of each power plant. As an example, if the dimensions of the channel are about 5 meters wide and 15 meters deep, and the water depth is about 9 meters at high tide and about 7 meters at low tide, the cooling water for the water channel about 5 meters wide and about 9 meters deep at high tide is 0. It is flowing in at a velocity of .3 m/s. Since the cooling water of the power plant is pumped by the seawater pump installed downstream of the dust remover, if dust adheres to the mesh on the upstream side of the dust remover and the water flow resistance increases, the water level on the downstream side of the dust remover first decreases. At this point, dust exists on the upstream side of the dust remover. Furthermore, even if the water level difference gauge on the upstream side of the dust remover measures the high water level and issues a high-speed operation command for the dust remover, the distance of 2 meters from the measurement position to the dust remover is about 6 seconds. Flowing water and dust collect on the upstream side of the dust remover and clog the screen in a short time. Even under such circumstances, high-speed operation is not started until the difference between the downstream side water level drop value and the upstream side water level rise value exceeds a preset value. The operating speed of the dust remover is changed when it exceeds the set reference value, and detection and countermeasures are not taken in the process of increasing the water level difference. If the amount of debris is small, there is no problem, but if a large amount of jellyfish flow into the air as a clump, measures to eliminate the difference in water level will be an afterthought. It has been demanded. It is also possible to operate the dust remover at high speed all the time, but it is not preferable because the amount of dust is small in normal times, and the frequency of maintenance increases due to power saving and equipment wear. In addition, the flow speed of the waterway is faster near the center than on the sides, and dust collects in places where the flow speed is fast. In other words, the dust tends to gather near the center of the dust remover, and the distribution of the amount of dust is uneven. For this reason, when switching operation modes based on the difference in water level, which was conventionally measured near the side of the channel, even if the difference in water level has decreased, dust may remain near the center of the channel, resulting in poor switching accuracy. was not stable.

JP 2017-20293 A JP 2015-168917 A Japanese Patent No. 2655029 JP-A-2001-64946

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to provide a method of operating a dust remover that can accurately switch the rotation speed of the screen according to the amount of dust in view of the above-described problems of the prior art.

The present invention, as a first means for solving the above problems, joins a net frame equipped with a dust collecting screen to an endless carrying chain, and drives the carrying chain through upper and lower sprocket wheels. In the operation method of the dust remover,
When the water level difference between the upstream side and the downstream side of the dust collecting screen that moves around at a first speed to capture dust exceeds a set value, or when the water level difference does not exceed the set value and the dust is collected a step of switching the rotation speed of the dust collecting screen to a second speed higher than the first speed when the flow speed on the upstream side of the screen drops below a set value;
When the water level difference between the upstream side and the downstream side of the dust collecting screen rotating at the second speed falls below a set value, and when the flow velocity on the upstream side of the dust collecting screen exceeds a set value and switching the rotational speed of the dust collecting screen to the first speed when the amount of dust captured by the dust collecting screen falls below a set value;
To provide a method for operating a dust remover characterized by:
According to the first means, it is possible to switch and control the rotation speed stepwise with high accuracy according to the amount of dust.

The present invention is a second means for solving the above problems, in the first means, characterized in that the water level difference and flow velocity are measured by a plurality of radar sensors arranged along the width direction of the waterway. The object of the present invention is to provide a method for operating a dust remover that
According to the second means, the water level difference and the flow velocity can be measured with high accuracy even under different water flow conditions in the width direction of the waterway, for example, when the flow velocity near the center of the waterway is higher than that on the side of the waterway.

As a third means for solving the above problems, the present invention provides a dust remover characterized in that, in the first or second means, the amount of dust is continuously measured by weight of dust per unit time. To provide a driving method.
According to the third means, it is possible to accurately measure the amount of dust according to the time-dependent change of the dust.

According to the present invention, it is possible to switch and control the rotation speed stepwise with high accuracy according to the amount of dust.

1 is a plan view of a dust remover of the present invention; FIG. It is explanatory drawing of a dust amount measuring part. It is a flow chart of the operation method of the dust remover of the present invention. It is a figure which shows the relationship between an operation mode, the amount of garbage collection|recovery, a water level difference, and a flow velocity signal. It is explanatory drawing of a dust removal apparatus.

An embodiment of a method for operating a dust remover of the present invention will be described in detail below with reference to the drawings.

[Dust remover 1]
(Water level difference and flow velocity measuring unit 10)
FIG. 1 is an explanatory diagram of the dust remover of the present invention. As shown in the figure, water level difference and flow velocity measuring units 10 are provided in the water channels on the upstream and downstream sides of the dust remover 1 .
The water level difference and flow velocity measuring unit 10 is a sensor capable of measuring the water level difference in the water channel (the difference between the water levels on the upstream side and the downstream side of the dust remover 1) and the flow velocity. A measurement sensor is applied. A non-contact radar type measurement sensor irradiates a radar signal from above the waterway toward the water surface and detects the reflected signal to measure the water level and flow velocity. The water level difference and flow velocity measuring unit 10 of this embodiment is arranged along the width direction of the waterway at a plurality of locations above the waterway (three locations near the center and both sides of the waterway), and at least one location where the waterway has a high flow velocity. (for example, near the center of the waterway). Generally, the flow velocity in the width direction of the channel is the fastest in the center of the channel and slower at both sides than at the center. For this reason, debris such as jellyfish also gathers in the center where the flow speed is fast and moves in the waterway. When the dust remover is reached, the dust is concentrated in the center in the width direction of the device, and the dust that has not been raked up moves from the center to both sides together with the dust newly added from the upstream side.

When obtaining the water level difference in the waterway in this embodiment, the measured value of any one sensor on the upstream side or the average value of all (three in this embodiment) sensors, and the one sensor on the downstream side or the difference between the average values of all sensors (three in this embodiment). Also, when obtaining the flow velocity of the waterway, the slowest measured value among the sensors on the upstream side (for example, when there is no dust, the measured value of both sides in the width direction of the waterway, and when it is clogged with dust, the dust ) are used.
Such a water level difference and flow velocity measuring unit 10 can be provided, for example, at a gate or bridge of a predetermined height arranged so as to straddle a waterway.

(Dust amount measurement unit 20)
FIG. 2 is an explanatory diagram of the dust amount measuring unit. A dust collection chute 21 of the dust remover 1 is provided with a dust amount measuring section 20 . The dust collection chute 21 is provided between the dust remover 1 and the dust collection section below, and adopts a structure in which the dust slides down the slope. The dust amount measuring unit 20 of the present embodiment is a weighing instrument provided between the chutes on which the dust slides down. are measuring.

[How to operate the dust remover]
FIG. 3 is a flow chart of the operating method of the dust remover of the present invention. FIG. 4 is a diagram showing the relationship between the operation mode, the amount of dust collected, and the water level difference/flow velocity signal.
(start operation)
At the start of operation of the dust remover 1, it is determined whether or not the water level difference is equal to or greater than a set value A (eg, 150 mm) (step 1). If YES, there is dust in the waterway, so the operation is switched to low speed (step 2). If NO in step 1 (if the water level difference is less than the set value A), it is determined whether or not the flow velocity on the upstream side of the dust remover is equal to or less than the set value a (eg, 0.3 m/s) (step 3 ). If the answer is NO, there is no dust to be collected in the waterway, so the process returns to step 1 to continue measuring the water level difference. If YES, there is dust in the waterway, so the operation is switched to low speed (step 2).

(Low speed operation)
During low-speed operation of the dust remover 1 in step 2, it is determined whether or not the water level difference is equal to or greater than a set value B (eg, 300 mm, A<B) (step 4). If YES, there is a large amount of dust in the water channel and the water level difference is increasing and decreasing, so the operation is switched to high speed operation (step 5). If NO in step 4 (when the water level difference is less than the set value B), it is determined whether or not the flow velocity is below a set value b (eg, 0.2 m/s, a>b) (step 6). Among the upstream water level difference and flow velocity measuring units 10, if the measured value in the central portion in the width direction of the waterway decreases, it can be determined that uncollected dust remains. Also, if the measured values of the central portion and both sides (at least one of them) are lowered, the dust raking capacity of the low speed operation is exceeded, so it is necessary to increase the operating speed. If the answer is YES, the water level difference is not yet generated, but since dust is becoming clogged, the operation is switched to high speed operation (step 5). If the answer is NO, the dust can be collected at the current operating speed, so the process returns to step 2 to continue the water level difference measurement while maintaining the low speed operation.

(high speed operation)
During high-speed operation in step 5, it is determined whether or not the water level difference is equal to or less than a set value A (eg, 150 mm, A<B) (step 7). In the case of NO, since there is still a large amount of dust, the process returns to step 5 to continue measuring the water level difference while maintaining high speed operation.
If YES, it is determined whether or not the flow velocity is equal to or greater than a set value b (eg, 0.2 m/s, a>b) (step 8). In the case of NO, since there is still a large amount of dust, the process returns to step 5 to continue measuring the water level difference while maintaining high speed operation.
If YES, it is determined whether or not the amount of dust is equal to or less than the set value (step 9). In the case of NO, since there is still a large amount of dust, the process returns to step 5 to continue measuring the water level difference while maintaining high speed operation.

(low speed operation/end)
If step 9 is YES, a large amount of debris has been collected in the waterway, so the operation is switched to low speed (step 10). After a predetermined time has passed, the dust remover is stopped and the process ends.
According to the operation method of the dust remover of the present invention, when switching from high-speed operation to low-speed operation, it is determined whether the amount of dust has fallen below the set value and switched to low speed. Even if the water level difference is eliminated, it is possible to solve the problem that the dust remains in uneven dust distribution and cannot be collected. In addition, even if the flow velocity varies in the width direction of the water channel and the amount of dust collected by the dust remover is uneven, the circulating speed can be switched and controlled in steps with high accuracy.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention.
Moreover, the present invention is not limited to the combinations shown in the embodiments, and can be implemented in various combinations.

1 Dust remover 2 Carrying chain 3B Lower sprocket wheel 4 Net frame 10 Water level difference and flow velocity measurement unit 20 Dust amount measurement unit 21 Dust collection chute

Claims (3)

In a method for operating a dust remover in which a mesh frame provided with a screen for collecting dust is joined to an endless carrying chain, and the carrying chain is driven through upper and lower sprocket wheels,
When the water level difference between the upstream side and the downstream side of the dust collecting screen that moves around at a first speed to capture dust exceeds a set value, or when the water level difference does not exceed a predetermined value and the dust is collected a step of switching the rotation speed of the dust collecting screen to a second speed higher than the first speed when the flow speed on the upstream side of the screen drops below a set value;
When the water level difference between the upstream side and the downstream side of the dust collecting screen rotating at the second speed falls below a set value, and when the flow velocity on the upstream side of the dust collecting screen exceeds a set value and switching the rotational speed of the dust collecting screen to the first speed when the amount of dust captured by the dust collecting screen falls below a set value;
A method of operating a dust remover, comprising: A method for operating a dust remover according to claim 1,
A method of operating a dust remover, wherein the water level difference and flow velocity are measured by a plurality of radar sensors arranged along the width direction of the waterway. A method for operating a dust remover according to claim 1 or claim 2,
A method of operating a dust remover, wherein the amount of dust is determined by continuously measuring the weight of the dust per unit time.

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