Industrial belt conveyor alarm start interlock control circuit

Abstract

The utility model discloses an industrial belt conveyor alarm starting interlock control circuit, including with single -phase ac power electric connection's audible -visual alarm and audible -visual alarm starting circuit, with audible -visual alarm starting circuit cooperation is equipped with frequency converter starting circuit, still include the audible -visual alarm stop circuit of starting signal control audible -visual alarm stoppage of utilization three -phase motor, and frequency converter still is connected with frequency converter stop circuit, through audible -visual alarm starting circuit starting audible -visual alarm, after a certain time delay, frequency converter starting circuit can make three -phase motor starting operation formally, after three -phase motor enters the operating state, can automatically start audible -visual alarm stop circuit and stop alarm, realize the alarm and starting interlock control of belt conveyor, make the alarm with starting need according to the order and implement under certain safety time interval, to prevent the misoperation of belt conveyor caused by improper operation, thereby guaranteeing the safe starting of belt conveyor.

Description

Technical Field

[0001] This utility model relates to the field of industrial conveyor start-up control technology, and in particular to an alarm start-up interlock control circuit for an industrial belt conveyor. Background Technology

[0002] In the production of steel, coal, and cement enterprises, belt conveyors are widely used due to their advantages such as simple structure, low cost, long transport distance, and high transport efficiency. However, due to their long installation distances and sometimes significant height differences depending on the usage scenario, the safe start-up of belt conveyors becomes particularly important and challenging. For example, during on-site start-up, due to length and height differences, it is impossible to observe whether personnel are lingering within the dangerous starting range of the belt conveyor for maintenance, inspection, or other reasons. Therefore, audible and visual alarms are usually installed at intervals along both sides of the belt conveyor. When starting the belt conveyor, the audible and visual alarms are manually activated first to provide a warning, and after a period of time, the motor is manually started. In this operating method, the duration of the audible and visual alarm warning is entirely controlled manually, which can lead to incomplete or insufficient evacuation of personnel due to a short warning time. Furthermore, the close proximity of the control terminals for the two functions also poses a risk of misoperation. Therefore, it is difficult to completely eliminate safety accidents caused by belt conveyor start-up. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide an alarm start interlock control circuit for industrial belt conveyors that can provide early warning first, then start after a delay, and the two can be automatically coordinated. The warning time is adjustable and the operation is safe and reliable.

[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is: an alarm start interlock control circuit for an industrial belt conveyor, used in conjunction with a frequency converter (VFD). The VFD is electrically connected to a three-phase motor M for driving the belt conveyor. It includes an audible and visual alarm S electrically connected to a single-phase AC power supply, and an audible and visual alarm start circuit for controlling the alarm S to activate. The audible and visual alarm start circuit is electrically connected to both the alarm S and the single-phase AC power supply. A frequency converter start circuit is provided in conjunction with the audible and visual alarm start circuit. The frequency converter start circuit is connected to the VFD. The frequency converter start circuit uses the start signal from the alarm S to control the three-phase motor M to start running with a delay. It also includes an audible and visual alarm stop circuit that uses the start signal from the three-phase motor M to control the alarm S to stop activating. The VFD is also connected to a frequency converter stop circuit, which controls the three-phase motor M to stop running.

[0005] As a preferred technical solution, the audible and visual alarm activation circuit includes a normally closed circuit switch SB1 connected to the single-phase AC power supply, a normally open contact KA1-1 of an intermediate relay KA1 and the audible and visual alarm S connected in series with the normally closed circuit switch SB1, a normally closed circuit switch SB2 connected in parallel with the audible and visual alarm S, a normally closed circuit switch SB2 connected in series with the normally closed circuit switch SB2, a normally closed contact KA2-1 of an intermediate relay KA2 and an intermediate relay KA1, a time delay relay KT1 connected in parallel with the intermediate relay KA1, and a normally open contact KA1-2 of an intermediate relay KA1 connected in parallel with the normally closed circuit switch SB2.

[0006] As a preferred technical solution, the inverter start circuit includes a normally open contact KT1-1 of a time delay relay KT1 connected to the inverter VFD, and an inverter start button SB3 is connected in series with the normally open contact KT1-1 of the time delay relay KT1. When the control unit of the inverter VFD receives a signal that the audible and visual alarm S has been activated, it controls the inverter start circuit to enter the preparation start state.

[0007] As a preferred technical solution, the audible and visual alarm stop circuit includes an intermediate relay KA2 connected to the frequency converter VFD. When the control unit of the frequency converter receives a signal that the three-phase motor M has started, it controls the intermediate relay KA2 to be energized.

[0008] As a preferred technical solution, a motor running indicator light HG is connected in parallel with the intermediate relay KA2.

[0009] As an improvement to the above technical solution, the inverter stop circuit includes a motor normally closed stop switch SB4 electrically connected to the inverter VFD.

[0010] Due to the adoption of the above technical solution, this utility model has the following beneficial effects: the audible and visual alarm is activated by the audible and visual alarm start circuit. After a certain delay, the frequency converter start circuit can officially start the three-phase motor. After the three-phase motor enters the running state, the audible and visual alarm stop circuit can be automatically activated to stop the alarm, realizing the alarm and start interlock control of the belt conveyor. The alarm and start must be implemented in sequence and at a certain safe time interval to prevent the belt conveyor from being started by mistake due to improper operation, thereby ensuring the safe start of the belt conveyor. Attached Figure Description

[0011] The following figures are intended only to illustrate and explain the present invention and do not limit the scope of the present invention. Wherein: Figure 1 This is a simplified wiring diagram of the frequency converter according to an embodiment of this utility model; Figure 2This is a schematic diagram of the sound and light alarm activation circuit according to an embodiment of this utility model; Figure 3 This is a schematic diagram of the inverter starting circuit according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the sound and light alarm stop circuit according to an embodiment of this utility model; Figure 5 This is a schematic diagram of the inverter stop circuit according to an embodiment of this utility model. Detailed Implementation

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the following detailed description, only certain exemplary embodiments of the present invention are described by way of illustration. Undoubtedly, those skilled in the art will recognize that various modifications can be made to the described embodiments without departing from the spirit and scope of the present invention. Therefore, the drawings and description are illustrative in nature and not intended to limit the scope of the claims.

[0013] like Figures 1 to 5 As shown, the industrial belt conveyor alarm start interlock control circuit is used in conjunction with a frequency converter (VFD). The VFD is a high-voltage frequency converter equipped with a control unit, digital input interface, analog input interface, communication interface, etc. The VFD is electrically connected to a three-phase motor M for driving the belt conveyor, realizing the start and stop control of the three-phase motor M, thereby realizing the operation control of the belt conveyor.

[0014] This embodiment includes an audible and visual alarm S electrically connected to a 220V single-phase AC power supply, an audible and visual alarm activation circuit for controlling the audible and visual alarm S to activate the alarm, and the audible and visual alarm activation circuit is electrically connected to both the audible and visual alarm S and the single-phase AC power supply. A frequency converter activation circuit is provided in conjunction with the audible and visual alarm activation circuit, and the frequency converter activation circuit is connected to the frequency converter VFD. The frequency converter activation circuit uses the activation signal from the audible and visual alarm S to control the three-phase motor M to start running after a delay. It also includes an audible and visual alarm stop circuit that uses the activation signal from the three-phase motor M to control the audible and visual alarm S to stop activating the alarm. The frequency converter VFD is also connected to a frequency converter stop circuit, and the frequency converter stop circuit controls the three-phase motor M to stop running.

[0015] When the three-phase motor M needs to be started, the audible and visual alarm S is first activated through the audible and visual alarm start circuit. After the audible and visual alarm S emits an audible and visual alarm signal and continues for a period of time, the frequency converter start circuit can then officially start the three-phase motor M. Once the three-phase motor M enters the running state, the audible and visual alarm stop circuit will be automatically activated to stop the audible and visual alarm S from activating, thus completing the alarm and start interlock control of the belt conveyor. This prevents the belt conveyor from being accidentally started due to improper operation, thereby ensuring the safe start of the belt conveyor.

[0016] like Figure 2 As shown, the audible and visual alarm activation circuit includes a normally closed circuit switch SB1 connected to the single-phase AC power supply. A normally open contact KA1-1 of an intermediate relay KA1 and the audible and visual alarm S are connected in series with the normally closed circuit switch SB1. A normally open circuit switch SB2 is connected in parallel with the audible and visual alarm S. A normally closed contact KA2-1 of an intermediate relay KA2 and an intermediate relay KA1 are connected in series with the normally open circuit switch SB2. A time delay relay KT1 is connected in parallel with the intermediate relay KA1. A normally open contact KA1-2 of the intermediate relay KA1 is connected in parallel with the normally open circuit switch SB2, forming a self-locking circuit for the intermediate relay KA1 and the normally open circuit switch SB2.

[0017] When the main circuit switch SB2 is pressed, the intermediate relay KA1 and the time-delay relay KT1 are energized. The normally closed contact KA2-1 of the intermediate relay KA2 closes, and the audible and visual alarm S is activated, emitting an alarm signal. The time-delay relay KT1 begins its delayed start control; the specific delay time of the time-delay relay KT1 can be set according to the specific application scenario. Simultaneously, the normally open contact KA1-2 of the intermediate relay KA1 also closes, exercising its self-locking function to ensure stable circuit operation.

[0018] like Figure 3 As shown, when the control unit of the VFD receives a signal that the audible and visual alarm S has been activated, it controls the VFD start-up circuit to enter a ready-to-start state. This signal can be generated by the VFD's built-in PLC controller or external PLC controller in conjunction with various relays, and is equivalent to a trigger signal to activate the VFD start-up circuit. The VFD start-up circuit includes the normally open contact KT1-1 of the time-delay relay KT1 connected to the VFD, and a VFD start button SB3 is connected in series with the normally open contact KT1-1 of the time-delay relay KT1. The VFD start button SB3 can be pressed sequentially with the circuit's normally open main switch SB2, with no specific order required.

[0019] When the inverter start button SB3 is pressed, if the audible and visual alarm S does not sound, it indicates that its circuit is not open. Therefore, the time-delay relay KT1 will not be triggered, and its normally open contact KT1-1 will remain open. Consequently, the inverter start circuit cannot close, and the inverter VFD cannot start the three-phase motor M. Only when the main circuit switch SB2 is pressed, energizing the intermediate relay KA1 and the time-delay relay KT1, will the audible and visual alarm S sound. After a delay, the normally open contact KT1-1 of the time-delay relay KT1 will automatically close, closing the inverter start circuit, allowing the inverter VFD to successfully start the three-phase motor M. The audible and visual alarm start circuit works in conjunction with the inverter start circuit to ensure that the audible and visual alarm S sounds first before the three-phase motor M starts, thus preventing accidental starting of the three-phase motor M.

[0020] like Figure 4 As shown, the audible and visual alarm stop circuit includes an intermediate relay KA2 connected to the frequency converter VFD. When the control unit of the frequency converter VFD receives a signal that the three-phase motor M has started, it controls the intermediate relay KA2 to be energized. The method by which the control unit of the frequency converter VFD receives the signal that the three-phase motor M has started is similar to that described above and will not be described in detail here. After the three-phase motor M is energized and starts running, the intermediate relay KA2 is energized under its energization signal trigger. The normally closed contact KA2-1 of the intermediate relay KA2 opens, thereby de-energizing the intermediate relay KA1 and the time delay relay KT1. The normally open contact KA1-1 of the intermediate relay KA1 enters the normally open state, and the audible and visual alarm S is de-energized and stops alarming. The normally open contact KT1-1 of the time delay relay KT1 only participates in the start control of the frequency converter VFD. The maintenance of the frequency converter VFD after startup is maintained by other conventional circuits. A motor running indicator light HG is connected in parallel with the intermediate relay KA2 to indicate the energization status of the three-phase motor M.

[0021] The inverter stop circuit includes a motor stop switch SB4 electrically connected to the inverter VFD. When it is necessary to stop the operation of the belt conveyor, pressing the motor stop switch SB4 will stop the operation of the three-phase motor M. The inverter VFD is also equipped with conventional indication or control circuits such as reset, emergency stop, operation, and fault indication, which will not be described in detail here.

[0022] This embodiment has been tested in large-scale belt conveyor projects such as Yongfeng Steel and Jiangsu Changqiang Steel, and can ensure the safe start-up of belt conveyors and avoid unnecessary losses caused by misoperation.

[0023] The description of this utility model is given for illustrative and descriptive purposes only, and is not intended to be exhaustive or to limit the utility model to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the utility model, and to enable those skilled in the art to understand the utility model and design various embodiments with various modifications suitable for a particular purpose.

Claims

1. An alarm start interlock control circuit for an industrial belt conveyor, used in conjunction with a frequency converter (VFD), wherein the VFD is electrically connected to a three-phase motor M for driving the belt conveyor, characterized in that: The system includes an audible and visual alarm S electrically connected to a single-phase AC power supply, an audible and visual alarm activation circuit for controlling the audible and visual alarm S to activate the alarm, and the audible and visual alarm activation circuit is electrically connected to both the audible and visual alarm S and the single-phase AC power supply. A frequency converter activation circuit is provided in conjunction with the audible and visual alarm activation circuit and is connected to the frequency converter VFD. The frequency converter activation circuit uses the activation signal from the audible and visual alarm S to control the three-phase motor M to start running after a delay. The system also includes an audible and visual alarm stop circuit that uses the activation signal from the three-phase motor M to control the audible and visual alarm S to stop activating the alarm. The frequency converter VFD is also connected to a frequency converter stop circuit, which controls the three-phase motor M to stop running.

2. The alarm start interlock control circuit for industrial belt conveyors as described in claim 1, characterized in that: The audible and visual alarm activation circuit includes a normally closed circuit switch SB1 connected to the single-phase AC power supply, a normally open contact KA1-1 of an intermediate relay KA1 and the audible and visual alarm S connected in series with the normally closed circuit switch SB1, a normally closed circuit switch SB2 connected in parallel with the audible and visual alarm S, a normally closed circuit switch SB2 connected in series with the normally closed circuit switch SB2, a normally closed contact KA2-1 of an intermediate relay KA2 and an intermediate relay KA1, a time delay relay KT1 connected in parallel with the intermediate relay KA1, and a normally open contact KA1-2 of an intermediate relay KA1 connected in parallel with the normally closed circuit switch SB2.

3. The alarm start interlock control circuit for industrial belt conveyors as described in claim 2, characterized in that: The inverter start circuit includes a normally open contact KT1-1 of a time delay relay KT1 connected to the inverter VFD, and an inverter start button SB3 is connected in series with the normally open contact KT1-1 of the time delay relay KT1. When the control unit of the inverter VFD receives a signal that the audible and visual alarm S has been activated, it controls the inverter start circuit to enter the preparation start state.

4. The alarm start interlock control circuit for industrial belt conveyors as described in claim 1, characterized in that: The audible and visual alarm stop circuit includes an intermediate relay KA2 connected to the frequency converter VFD. When the control unit of the frequency converter VFD receives a signal that the three-phase motor M has started, it controls the intermediate relay KA2 to be energized.

5. The alarm start interlock control circuit for industrial belt conveyors as described in claim 4, characterized in that: A motor running indicator light HG is connected in parallel with the intermediate relay KA2.

6. The alarm start interlock control circuit for industrial belt conveyors as described in claim 1, characterized in that: The inverter stop circuit includes a motor automatic stop switch SB4 that is electrically connected to the inverter VFD.

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