Coal blocking protection method for coal falling barrel of coal conveying belt based on current detection

Abstract

The invention relates to the technical field of coal conveying belts, in particular to a coal conveying belt coal falling barrel coal blockage protection method based on current detection, which comprises the following steps: dividing a coal conveying system belt into a coal unloading line and a coal loading line by taking a coal storage yard in a power plant as a boundary; electronic belt scales are arranged on source belts of a coal unloading line and a coal feeding line and used for monitoring the instantaneous coal amount of the belts in real time and conveying the coal amount weight to a coal conveying control system. The method can effectively solve the problems of material scattering and the like caused by blockage of materials below the belt and at the hopper of the machine head of the belt conveyor, so that the belt is prevented from slipping, being abraded and even being torn, and coal blockage and coal overflow of a coal conveying system are effectively prevented.

Description

Technical Field

[0001] The invention relates to the technical field of coal conveyor belts, in particular to a method for protecting a coal conveyor belt from coal blockage in a coal drop shaft based on current detection. Background Art

[0002] The coal conveyor belt of a coal-fired power plant is a key equipment for coal transportation, and its safe and stable operation is crucial to the normal power generation of the power plant. Coal blockage in the belt coal dropper is one of the common faults in the coal transportation system. When the coal quality changes greatly, there are many lumps of coal, or the moisture content of the coal is high, a large amount of coal overflow often occurs due to the blockage of the coal dropper, which brings great difficulties to the safe operation of the unit and the restoration of the belt coal loading. At the same time, a large amount of coal cleaning work not only increases the manpower expenditure, but also increases a large amount of coal cleaning costs.

[0003] The significance of the coal conveyor belt blocking protection system is to prevent a series of problems caused by coal blocking in the coal drop barrel during the transportation process, including abnormal shutdown of the belt conveyor, coal overflow, belt wear and even breakage, and possible safety accidents. After the coal drop barrel is blocked, a large amount of coal will overflow from the barrel, causing great pressure on on-site environmental protection. At the same time, production is forced to be interrupted, and a large amount of manpower and material resources need to be organized for dredging and cleaning. The labor intensity of personnel is high, the risk is high, and a large amount of downtime is consumed, which seriously restricts the improvement of production efficiency and the improvement of on-site environmental sanitation. Through effective coal blocking protection measures, equipment failures can be reduced, equipment service life can be extended, and the continuity of coal transportation can be ensured, thereby ensuring the stable operation of the power plant and improving power generation efficiency.

[0004] The traditional coal conveyor belt uses a rotating coal blocking protection switch. The rotating coal blocking switch of the coal conveyor belt leakage drum is a safety protection device used to monitor the coal flow state in the coal conveyor belt leakage drum or coal drop pipe. Its core working principle is to use the motor to drive the blade to rotate. When the coal powder is blocked, the blade is blocked by the coal powder and stops rotating. After the blade stops rotating, the resistance torque drives the internal mechanism of the motor to move, sends out an action signal, and cuts off the power supply of the motor to stop the motor. When the coal powder leaves the blade, the blade returns to its original position and continues to rotate under the action of the spring.

[0005] Although the traditional coal conveyor belt rotation-blocking protection system can monitor and protect against coal blockage to a certain extent, it has the possibility of refusal to operate and false operation and the following disadvantages:

[0006] In actual operation, the rotary-type coal-blocking switch may often malfunction or fail to operate when there is a real coal blockage, which will affect the safe and reliable operation of the coal transportation system.

[0007] Easily affected by material characteristics: Materials with high viscosity, high humidity or irregular particle shapes may cause the anti-rotation blades to get stuck or malfunction.

[0008] For example, when processing coal slime with a high water content, the material may adhere to the blades, affecting their normal rotation and mistakenly sending a coal blockage signal.

[0009] High requirements for the installation location: It needs to be installed in a specific location to accurately detect coal blockage. If it is not installed properly, it may lead to inaccurate detection or failure to detect coal blockage.

[0010] For example, if the installation position is too close to the feed port, the impact force of the material may interfere with the normal rotation of the blades, causing malfunction. Or if the coal bridges the coal drop tube and forms coal overflow, but there is no coal blocking the blade where the coal blocking switch detects the blade, it will cause refusal to operate and fail to play the role of coal blocking protection.

[0011] When the detection blade falls off or the internal structure of the coal-blocking switch is damaged or coal is blocked, jitter may occur. Summary of the invention

[0012] In view of the problems existing in the prior art, the present invention is proposed.

[0013] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for protecting the coal conveyor belt from coal blockage in the coal drop tube based on current detection, comprising: dividing the coal conveyor system belt into a coal unloading line and a coal loading line with the coal storage yard in the power plant as the boundary; an electronic belt scale is arranged at the source belts of the coal unloading line and the coal loading line to monitor the instantaneous coal quantity on the belt in real time, and transmit the weight of the coal to the coal conveying control system.

[0014] As an optimal solution of the coal blocking protection method of the coal conveyor belt coal hopper based on current detection described in the present invention, it includes: real-time monitoring of the operating current of each coal conveyor belt driving motor, and obtaining the operating current data by installing a current sensor in the motor control cabinet circuit, and collecting it to the coal conveying control system.

[0015] As an optimal solution of the coal blockage protection method for the coal hopper of a coal conveyor belt based on current detection described in the present invention, the normal operating current range of each belt is set, and the upper and lower limit thresholds of the current corresponding to different coal transport volumes during normal operation are determined according to the design parameters, load characteristics and historical operating data of each belt system.

[0016] As an optimal solution of the coal blocking protection method of the coal conveyor belt coal hopper based on current detection described in the present invention, a belt coal blocking judgment model is established, the weight of the conveyed coal and the corresponding current value of the belt are measured by the source belt scale, and the corresponding matrix relationship between the different coal conveying amounts and currents of each belt is established.

[0017] As a preferred scheme of the coal blockage protection method for the coal conveyor belt coal hopper based on current detection described in the present invention, the coal blockage protection criteria are: abnormal increase in the current of the coal blocking belt, no synchronous increase or even decrease in the downstream belt current, and an increase in the difference between the upstream belt current and the downstream belt current, exceeding the set threshold value.

[0018] As a preferred solution of the method for protecting the coal conveyor belt from coal blockage based on current detection described in the present invention, it also includes a coal blockage protection alarm output, which includes setting a coal blockage protection program in the coal conveying control system, and setting an alarm interface on the operator monitoring screen, and an external sound alarm.

[0019] As a preferred solution of the method for protecting the coal conveyor belt from coal blockage based on current detection described in the present invention, the belt coal blockage protection is divided into three levels. If the three criteria are met at the same time, all the belt equipment protection upstream of the coal blockage point will be directly stopped and the highest level red alarm will be issued.

[0020] As a preferred solution of the method for protecting the coal conveyor belt from coal blockage based on current detection described in the present invention, when two criteria are met at the same time, an orange alarm is issued with a delay of 3 seconds, and all the belt protection equipment upstream of the coal blockage point is tripped and stopped.

[0021] As a preferred solution of the method for protecting the coal conveyor belt from coal blockage based on current detection described in the present invention, when one criterion is met, a yellow alarm is issued with a delay of 5 seconds, and all the protection devices of the belt upstream of the coal blockage point are tripped and stopped.

[0022] Beneficial effects of the invention: The purpose of the invention is to provide a method and device for preventing coal blockage in the coal hopper of a belt conveyor based on current detection. The method can effectively solve the problem of material spillage caused by material blockage under the belt and in the funnel of the belt conveyor head, so as to prevent the belt from slipping, wearing or even tearing, and effectively prevent the occurrence of coal blockage and coal overflow in the coal conveying system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0024] Figure 1 It is a schematic diagram of the working process of the coal unloading coal line in the present invention.

[0025] Figure 2 It is a schematic diagram of the working process of the upper coal line in the present invention. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0029] Example 1, reference Figure 1 to Figure 2 , is an embodiment of the present invention, which provides a method for protecting the coal conveyor belt from coal blockage based on current detection.

[0030] Specifically, the coal storage yard in the power plant is used as the boundary to divide the coal conveying system belt into a coal unloading line and a coal loading line;

[0031] Electronic belt scales are installed at the source belts of the coal unloading line and the coal loading line to monitor the instantaneous coal volume of the belts in real time and transmit the weight of the coal volume to the coal transportation control system. The operating current of each coal conveying belt drive motor is monitored in real time, and the operating current data is obtained by installing current sensors in the motor control cabinet circuit and collected to the coal transportation control system. The normal operating current range of each belt is set, and the upper and lower limit thresholds of the current corresponding to different coal transportation volumes during normal operation are determined according to the design parameters, load characteristics and historical operating data of each belt system. A belt coal blockage judgment model is built, and the weight of the conveyed coal and the corresponding current value of the belt are measured by the source belt scale, and the corresponding matrix relationship between the different coal transportation volumes and currents of each belt is established.

[0032] The coal blocking protection criteria are: abnormal increase in the current of the coal blocking belt, no synchronous increase or even decrease in the downstream belt current, and the difference between the upstream belt current and the downstream belt current increases and exceeds the set threshold value. It also includes coal blocking protection alarm output, which includes setting a coal blocking protection program in the coal transportation control system, setting an alarm interface on the operator monitoring screen, and external sound alarm.

[0033] The belt coal blockage protection is divided into three levels. If all three criteria are met at the same time, all belt protection equipment upstream of the coal blockage point will be directly tripped and stopped, and the highest level red alarm will be issued. If two criteria are met at the same time, an orange alarm will be issued with a delay of 3 seconds, and all belt protection equipment upstream of the coal blockage point will be tripped and stopped. If one criterion is met, a yellow alarm will be issued with a delay of 5 seconds, and all belt protection equipment upstream of the coal blockage point will be tripped and stopped.

[0034] In summary, the coal transportation system belt is divided into coal unloading line and coal loading line based on the coal storage yard in the power plant.

[0035] Coal unloading line: The coal transported by ships is unloaded to the source belt X1 through the dock unloader, and the coal is relayed to the coal yard stacker and reclaimer through the coal unloading line belts X1, X2---Xi in sequence for stacking. Therefore, the coal unloading line is responsible for receiving and unloading the purchased coal of the power plant and stacking it in the coal yard.

[0036] Coal loading line: Coal is stored in the circular coal storage yard, and the stacker-reclaimer takes the coal, and then delivers it to the raw coal bunker through the coal loading line belts S1, S2---Si in turn, for the fuel supply of the boiler. The coal loading line is responsible for transporting the coal stored in the power plant to the raw coal bunker of the boiler through the belts and the coal drop hoppers of each transfer station.

[0037] Electronic belt scales are installed at the source belts of the coal unloading line and the coal loading line to monitor the instantaneous amount of coal on the belt in real time, and transmit the coal weight to the coal handling control system (DCS or PLC).

[0038] Monitor the operating current of each coal conveyor belt drive motor in real time. Install current sensors in the motor control cabinet circuit to obtain operating current data and collect them into the coal conveyor control system (DCS or PLC).

[0039] Set the normal operating current range of each belt. According to the design parameters, load characteristics and historical operating data of each belt system, determine the upper and lower limit thresholds of the current corresponding to different coal transport volumes during normal operation.

[0040] Build a coal-blocking judgment model for the belt. When the belt is conveying coal normally, the weight of the coal conveyed by the belt and the corresponding current value can be measured through the source belt scale. Taking into account the speed of the belt, the corresponding amount of coal on the downstream belt and the time when the motor current changes can be calculated. Based on this, a corresponding matrix relationship between the different coal conveying amounts and currents of each belt is established, that is, a coal-blocking judgment model. When the coal conveyed by the upstream belt does not reach the downstream belt within the set time, that is, the downstream belt does not receive the coal transmitted by the upstream belt, the current of the downstream belt does not increase synchronously, and it can be judged that the upstream belt or the coal drop pipe has overflowed. At the same time, when the coal drop pipe of the belt is blocked, the overflowing coal will hinder the running belt, and the current will also increase.

[0041] Compare the relationship between the amount of coal transported by this belt and the current table——

[0042]

[0043] According to the above principles, the coal blocking protection criteria are divided into three items:

[0044] 1. The current of the coal blocking belt increases abnormally;

[0045] 2. The downstream belt current does not increase synchronously or even decreases.

[0046] 3. The difference between the upstream belt current and the downstream belt current increases and exceeds the set threshold value.

[0047] Coal blocking protection alarm output: Set up a coal blocking protection program in the coal handling control system, set up an alarm interface on the operator monitoring screen, and set up an external sound alarm. Based on the above criteria, the belt coal blocking protection is divided into 3 levels. If all three criteria are met at the same time, all belt protection equipment upstream of the coal blocking point will be directly tripped and stopped, and the highest level red alarm will be issued. If two criteria are met at the same time, an orange alarm will be issued with a delay of 3 seconds, and all belt protection equipment upstream of the coal blocking point will be tripped and stopped. If one criterion is met, a yellow alarm will be issued with a delay of 5 seconds, and all belt protection equipment upstream of the coal blocking point will be tripped and stopped.

[0048] Total coal flow: The rated total amount of coal conveyor belt conveyor, which is measured by the electronic belt scale installed on the belt at the source of coal flow.

[0049] Coal transfer: The working process of the coal unloading line: the coal transported by the ship is unloaded to the source belt X1 through the dock unloader, and the coal is relayed to the coal yard stacker and reclaimer through the coal unloading line belts X1, X2---Xi for stacking. Therefore, the coal unloading line is responsible for the unloading and stacking of the coal purchased by the power plant in the coal yard. Similarly, the working process of the coal loading line: the stored coal in the circular coal yard is taken by the stacker and reclaimer, and is relayed to the raw coal bunker through the coal loading line belts S1, S2---Si for fuel supply to the boiler.

[0050] Working principle of coal blockage judgment module: The source belts of the coal loading line and the coal unloading line are equipped with electronic belt scales, which can monitor the amount of coal transported by the belts in real time. Establish the current value corresponding to the different coal transport amounts of each belt; at the same time, take into account the transport time of the coal flow through each belt. We can establish the corresponding current values ​​when different coal flows pass through each belt in turn. However, when coal piles occur, the current value of the downstream belt will be less than the set normal value because the upstream belt or coal drop tube has overflowed coal, and the coal flow has not reached the downstream belt at a fixed time. We can judge that the upstream belt or coal drop tube has overflowed coal. Taking into account other factors that may affect the current, such as the tightness of the belt, we set an allowable deviation range for the current value. Once this range value is exceeded, we will issue a coal blockage warning.

[0051] Working principle of coal blocking protection based on current detection: When the belt is conveying coal normally, the weight of the conveyed coal and the corresponding current value can be measured by the source belt scale. Considering the speed of the belt, the time when the current of the downstream belt changes can be calculated. Based on this, a corresponding matrix of different coal quantities and currents is established, namely the coal blocking judgment model.

[0052] When the coal conveyed by the belt fails to reach the downstream within the set time and reacts on the downstream belt current, it can be determined that coal overflow has occurred in the upstream belt or coal drop pipe.

[0053] During normal transportation, for a stable coal flow, the difference in current values ​​between the upstream belt and the downstream belt always exists within a certain range. When the upstream belt is blocked by coal, the current value of the upstream belt will increase abnormally due to the resistance caused by the overflowing coal. The current of the downstream belt will decrease due to the overflowing coal from the upstream. Based on this principle, the system will also send out a coal blockage protection signal.

[0054] The running current of the coal conveyor belt driving motor is collected to the coal conveying control system through the current sensor. At the same time, an electronic belt scale is added to the source belt of the coal conveying system (coal unloading line, coal loading line) to measure the instantaneous flow rate Q instantaneous of the conveyor belt in real time. The coal flow will be relayed to the coal yard through each belt in turn (coal unloading line, the coal coming from the factory is transported to the coal yard for stacking through the coal unloading belt. Coal loading line, the coal stored in the coal yard is transported to the raw coal bin through the coal loading line belt for boiler power generation.) For details of the coal conveyor belt flow chart, see Figure 1 .

[0055] It has the following advantages:

[0056] 1. Based on the high sensitivity of belt current detection, it avoids the risks of false operation and refusal to operate of the traditional rotary coal blocking protection switch.

[0057] 2. Relying on the coal conveying program control system, it can have self-learning function according to the operation of the belt, and the judgment criteria can be set flexibly.

[0058] 3. Introduce belt scale measurement, establish a coal blockage judgment model between the corresponding coal quantity and current of each belt, and the coal blockage judgment is highly accurate.

[0059] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), installation arrangement, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of performing the function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to several modifications still falling within the scope of the appended claims.

[0060] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0061] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0062] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for protecting the coal conveyor belt from coal blockage based on current detection, characterized in that: include, The coal storage yard in the power plant is used as the boundary to divide the coal conveying system belt into a coal unloading line and a coal loading line; Electronic belt scales are installed on the source belts of the coal unloading line and the coal loading line to monitor the instantaneous coal quantity on the belt in real time and transmit the coal quantity weight to the coal transportation control system.

2. The method for protecting the coal conveyor belt from coal blockage based on current detection according to claim 1, characterized in that: Monitor the operating current of each coal conveyor belt drive motor in real time, and obtain the operating current data by installing current sensors in the motor control cabinet circuit and collect them into the coal conveyor control system.

3. The method for protecting the coal conveyor belt from coal blockage based on current detection according to claim 1 or 2, characterized in that: The normal operating current range of each belt is set, and the upper and lower limit thresholds of the current corresponding to different coal transport volumes during normal operation are determined based on the design parameters, load characteristics and historical operating data of each belt system.

4. The method for protecting the coal conveyor belt from coal blockage based on current detection according to claim 3, characterized in that: A belt coal blockage judgment model is built, and the weight of the coal transported by the belt and the corresponding current value are measured by the source belt scale, and the corresponding matrix relationship between the different coal transport volume and current of each belt is established.

5. The method for protecting the coal conveyor belt from coal blockage based on current detection according to claim 4, characterized in that: The coal blocking protection criteria are: abnormal increase in coal blocking belt current, no synchronous increase or even decrease in downstream belt current, and increase in the difference between upstream belt current and downstream belt current, exceeding the set threshold value.

6. The method for protecting the coal conveyor belt from coal blockage based on current detection according to claim 5, characterized in that: It also includes a coal blockage protection alarm output, which includes setting a coal blockage protection program in the coal transportation control system, setting an alarm interface on the operator monitoring screen, and an external sound alarm.

7. The method for protecting the coal conveyor belt from coal blockage based on current detection according to claim 6, characterized in that: The protection against coal blockage on the belt is divided into three levels. If all three criteria are met at the same time, all the belt protection equipment upstream of the coal blockage point will be directly stopped and the highest level red alarm will be issued.

8. The method for protecting the coal conveyor belt from coal blockage based on current detection according to claim 6, characterized in that: If both criteria are met at the same time, an orange alarm will be issued with a delay of 3 seconds, and all protective equipment on the belt upstream of the coal blockage will be stopped.

9. The method for protecting the coal conveyor belt from coal blockage based on current detection according to claim 6, characterized in that: If one criterion is met, a yellow alarm will be issued with a delay of 5 seconds, and all protective equipment on the belt upstream of the coal blockage will be stopped.

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