Electric heating tube explosion-proof early warning device

Abstract

The invention discloses an electric heating tube explosion-proof early warning device which comprises a three-way circuit breaker QS, a three-way fuse FU, a three-way alternating current contactor KM, three-way alternating current mutual inductors LH1, LH2 and LH3, a self-reset temperature controller, a manual reset temperature controller, a current detection controller, a resistance sensor RH, a power switch SA1, a heating signal control switch SA2, a motor M and a capacitor C, wherein one ends of the three circuit breakers QS are respectively connected with three-phase input ends L1, L2 and L3 of a 380V live wire. During factory inspection, the voltage of equipment to which the electric heating tube belongs is adjusted to rated voltage through the voltage regulator, after the equipment operates for a period of time and is stable, the resistance value and the current value of the equipment to which the electric heating tube belongs are detected, and the detected resistance value and the detected current value are set as standard values. And when the air inlet of the fan equipment connected with the electric heating tube is blocked or the motor is stuck, and the self-reset temperature rises to a set value, the self-reset temperature controller is disconnected, so that the alternating current contactor is disconnected, and the fan equipment used for cooling the electric heating tube is delayed for a second time, and then the power supply is cut off.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric heating pipes, and in particular relates to an explosion-proof early warning device for electric heating pipes. Background Art

[0002] Heating elements (electric heating tubes) are components that convert electrical energy into heat and are widely used in industrial, domestic, and commercial applications. During use, a crack or rupture (rupture or explosion) of an electric heating element can not only damage the equipment but can also lead to serious safety incidents.

[0003] Common hazards of electric heating tube bursts are as follows: (1) Equipment damage and functional failure. After the electric heating tube bursts, it cannot work normally, causing the entire heating system to be paralyzed (such as a water heater that does not heat up, or an industrial reactor that loses temperature control). The internal resistance wire is exposed, which may short-circuit and burn the thermostat, fuse, or other circuit components. (2) Medium leakage. If the electric heating tube is used for liquid heating (such as a boiler or water tank), a burst tube may cause water, oil, or chemical medium to leak, polluting the environment or damaging other equipment. In industrial scenarios, the leakage of corrosive liquids (acids, alkalis) may cause secondary accidents. (3) Electrical safety hazards. Leakage risk - after the tube bursts, the metal casing or resistance wire contacts the medium (such as water), which may cause an electric shock accident. Short circuit fire - a short circuit in the internal circuit may generate an arc, igniting surrounding combustible materials (such as plastics and oil stains).

[0004] The above hazards of electric heating tube bursts show that it is necessary to promptly detect and prevent the risk of electric heating tube bursts. Summary of the Invention

[0005] In view of the above problems, the present invention provides an electric heating pipe explosion-proof warning device, which is used to issue a warning before the electric heating pipe explodes, thereby improving the safety of the electric heating pipe.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] An explosion-proof warning device for electric heating pipes includes a three-way circuit breaker QS, a three-way fuse FU, a three-way AC contactor KM, three-way AC mutual inductors LH1, LH2 and LH3, a self-reset thermostat, a manual reset thermostat, a current detection controller, a resistance sensor RH, a power switch SA1, a heating signal control switch SA2, a motor M and a capacitor C, wherein one end of the three-way circuit breaker QS is connected to the three-phase input terminals L1, L2 and L3 of the 380V live wire respectively, and the three-way circuit breaker The other end of the three-way fuse QS is connected to one end of the three-way fuse FU, the other end of the three-way fuse FU is connected to one end of the three-way AC contactor KM, the other end of the three-way AC contactor KM passes through the three-way current transformers LH1, LH2 and LH3 and is connected to one end of the Y-type three-phase electric heating tube R1, R2 and R3 respectively. One terminal of the three-way current transformers LH1, LH2 and LH3 is connected to the three input terminals of the current detection controller respectively, and the 380V neutral line N input terminal is connected to Connect one end of the self-reset thermostat, one end of the power indicator light and an input end of the current detection controller, the other end of the self-reset thermostat is connected to one end of the manual reset thermostat, the other end of the manual reset thermostat is connected to a contact of the KM coil, the other contact of the KM coil is connected to the P1 input end of the current detection controller, the other end of the fuse where the live wire L3 is located is connected to one end of the power switch, the other end of the power switch is connected to the other end of the power indicator light, the live wire input end of the current detection controller and an input end of the heating signal control switch SA2, the other end of the heating signal control switch SA2 is connected to the P2 input end of the current detection controller, the three output ends of the current detection controller are respectively connected to the L1 alarm indicator light, the L2 alarm indicator light and the L3 alarm indicator light, and the heating signal control switch SA2 is connected to the signal port of the digital display thermostat or the thermostat; 4 leads are set on the motor M, 2 of which are connected to the capacitor, and 2 wires are connected to the fan signal port inside the integrated electric control cabinet.

[0008] In one possible implementation, during factory inspection, the voltage of the equipment to which the electric heating tube belongs is adjusted to the rated voltage through a voltage regulator. When powered on, after running stably for a period of time, the resistance value and current of the equipment are detected, and the detected resistance value and current value are set as standard values.

[0009] In one possible implementation, when the air inlet of the fan device connected to the electric heating tube is blocked or the motor is stuck, the self-reset temperature rises to the set value, the self-reset thermostat is disconnected, and the AC contactor is disconnected. The fan device used to dissipate heat for the electric heating tube is delayed for a second time and then the power supply is cut off.

[0010] In one possible implementation, when the self-reset thermostat fails, the air inlet of the fan device connected to the electric heating tube is blocked or the motor is stuck, the temperature continues to rise, and after the manual reset temperature rises to the set value of the manual reset thermostat, the manual reset thermostat is disconnected, thereby disconnecting the AC contactor KM and cutting off the power supply.

[0011] In one possible implementation, after the power is turned on for the first time, the standard value of the circuit current is detected by three transformers. When any transformer detects that the current I in the circuit is ≥ the standard value * K1, the corresponding alarm indicator light flashes every 3 seconds, and the value of K1 is 1.2-2, and an alarm buzzer sounds. When the abnormality is eliminated, the power is turned off and reset after restarting.

[0012] In one possible implementation, after the power is turned on for the first time, the standard value of the circuit current is detected by three transformers. When any transformer detects that the current in the circuit is I≤standard value*K2, the corresponding alarm indicator light flashes every 3 seconds, and the value of K2 is 0.3-0.8, and an alarm beep sounds. When the abnormality is eliminated, the power is turned off and reset after restart.

[0013] In a possible implementation, the method further includes: the resistance sensor RH acquiring the resistance value of the electric heating tube in real time;

[0014] The on / off state of the fan and / or the on / off state of the contacts of the AC contactor are controlled according to the magnitude relationship between the resistance value and the resistance threshold.

[0015] In a possible implementation, controlling the switching state of the cooling mechanism and / or the on / off of the contacts of the AC contactor according to the relationship between the resistance value and the resistance threshold value includes:

[0016] If the resistance value is greater than the resistance threshold, the contacts of the AC contactor are controlled to be disconnected, and the fan is controlled to continue running for a preset time and then the power supply is cut off.

[0017] The present invention has the following beneficial effects: it can effectively realize explosion-proof prediction and explosion-proof early warning of electric heating pipes, and greatly improve the safety and effectiveness of the use of electric heating pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The figure is a circuit diagram of an electric heating tube explosion-proof warning device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] See also Figure 1 , shown is a circuit schematic diagram of an electric heating pipe explosion-proof warning device according to an embodiment of the invention, including a three-way circuit breaker QS, a three-way fuse FU, a three-way AC contactor KM, three-way AC transformers LH1, LH2 and LH3, a self-reset thermostat, a manual reset thermostat, a current detection controller, a resistance sensor RH, a power switch SA1, a heating signal control switch SA2, a motor M and a capacitor C, wherein one end of the three-way circuit breaker QS is connected to the three-phase input terminal of the 380V live wire respectively. L1, L2 and L3, the other end of the three-way circuit breaker QS is connected to one end of the three-way fuse FU, the other end of the three-way fuse FU is connected to one end of the three-way AC contactor KM, the other end of the three-way AC contactor KM passes through the three-way current transformers LH1, LH2 and LH3 and is respectively connected to one end of the Y-type three-phase electric heating tube R1, R2 and R3, one terminal of the three-way current transformers LH1, LH2 and LH3 is respectively connected to the three input terminals of the current detection controller, 380V The neutral line N input end is respectively connected to one end of the self-reset thermostat, one end of the power indicator light and an input end of the current detection controller; the other end of the self-reset thermostat is connected to one end of the manual reset thermostat; the other end of the manual reset thermostat is connected to a contact of the KM coil; the other contact of the KM coil is connected to the P1 input end of the current detection controller; the other end of the fuse where the live wire L3 is located is connected to one end of the power switch; the other end of the power switch is connected to the other end of the power indicator light, the live wire input end of the current detection controller and an input end of the heating signal control switch SA2; the other end of the heating signal control switch SA2 is connected to the P2 input end of the current detection controller; the three output ends of the current detection controller are respectively connected to the L1 alarm indicator light, the L2 alarm indicator light and the L3 alarm indicator light; the heating signal control switch SA2 is connected to the signal port of the digital display thermostat or the thermostat; four leads are set on the motor M, two of which are connected to the capacitor, and two wires are connected to the fan signal port inside the integrated electric control cabinet.

[0021] The above-mentioned electric heating pipe explosion-proof warning device is designed for factory inspection. The voltage of the equipment to which the electric heating pipe belongs is adjusted to the rated voltage through the voltage regulator. After the power is turned on and the device runs for a period of time to stabilize, the resistance value and current of the equipment are detected and set as the standard value. The period of time here can be, for example, 30 minutes.

[0022] After setting the standard resistance and current values, temperature control protection can be implemented. If the air inlet of the fan device connected to the electric heating pipe is blocked or the motor is stuck, the self-reset temperature rises to the set value, the self-reset thermostat disconnects, and the AC contactor disconnects. The fan device used to dissipate heat from the electric heating pipe delays for a second time and then cuts off the power supply. This is the automatic reset thermostat protection. The second time here can be, for example, 10 minutes.

[0023] When the self-reset thermostat fails, the air inlet of the fan device connected to the electric heating tube is blocked or the motor is stuck, the temperature continues to rise. After the manual reset temperature rises to the set value of the manual reset thermostat, the manual reset thermostat is disconnected, and the AC contactor KM is disconnected, cutting off the power supply. The above is the manual reset thermostat protection.

[0024] Another embodiment of the present invention is an electric heating pipe explosion-proof warning device. After the first startup, the standard value of the circuit current is detected by three mutual inductors. When any mutual inductor detects that the current I in the circuit is greater than or equal to the standard value * K1, the corresponding alarm indicator light flashes for 3 seconds / time, and the value of K1 is 1.2-2, and an alarm buzzer sounds. When the abnormality is eliminated, the power is cut off and reset after restart.

[0025] At the same time, after the first power-on, the standard value of the circuit current is detected through three transformers. When any transformer detects that the current in the circuit is I≤standard value*K2, the corresponding alarm indicator light flashes every 3 seconds. The value of K2 is 0.3-0.8, and an alarm buzzer sounds. When the abnormality is eliminated, the power is turned off and reset after restart.

[0026] Furthermore, in an embodiment of the present invention, an explosion-proof warning device for an electric heating tube is set up. Since the power of the electric heating tube will decay as the working time increases, the resistance will increase above the default value set before leaving the factory. When the resistance increases to the set value, the resistance sensor RH obtains the resistance value of the electric heating tube in real time during operation; and controls the switching state of the fan and / or the on-off of the contacts of the AC contactor according to the relationship between the resistance value and the resistance threshold.

[0027] Specifically, controlling the switching state of the cooling mechanism and / or the on / off of the contacts of the AC contactor according to the relationship between the resistance value and the resistance threshold may include: if the resistance value is greater than the resistance threshold, controlling the contacts of the AC contactor to be disconnected, and controlling the fan to continue running for a preset period of time before cutting off the power supply.

[0028] The heat pipe explosion-proof warning device set up above enables the electric heating pipe to have automatic reset thermostat protection function and manual reset thermostat protection function during use. It also has electric heating pipe explosion-proof prediction and warning function, which greatly improves the safety and effectiveness of the use of electric heating pipes.

[0029] It should be understood that the exemplary embodiments described herein are illustrative and not restrictive. Although one or more embodiments of the present invention have been described in conjunction with the accompanying drawings, it should be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. An explosion-proof warning device for electric heating pipes, characterized in that: It includes a three-way circuit breaker QS, a three-way fuse FU, a three-way AC contactor KM, a three-way AC mutual inductor LH1, LH2 and LH3, a self-reset thermostat, a manual reset thermostat, a current detection controller, a resistance sensor RH, a power switch SA1, a heating signal control switch SA2, a motor M and a capacitor C, wherein one end of the three-way circuit breaker QS is respectively connected to the 380V live wire three-phase input terminals L1, L2 and L3, the other end of the three-way circuit breaker QS is connected to one end of the three-way fuse FU, the other end of the three-way fuse FU is connected to one end of the three-way AC contactor KM, the other end of the three-way AC contactor KM passes through the three-way current mutual inductor LH1, LH2 and LH3 and is respectively connected to one end of the Y-type three-phase electric heating tube R1, R2 and R3, one terminal of the three-way current mutual inductor LH1, LH2 and LH3 is respectively connected to the three input terminals of the current detection controller, and the 380V neutral line N input terminal is respectively connected to the self-reset temperature controller. One end of the self-reset thermostat, one end of the power indicator light and an input end of the current detection controller, the other end of the self-reset thermostat is connected to one end of the manual reset thermostat, the other end of the manual reset thermostat is connected to a contact of the KM coil, the other contact of the KM coil is connected to the P1 input end of the current detection controller, the other end of the fuse where the live wire L3 is located is connected to one end of the power switch, the other end of the power switch is connected to the other end of the power indicator light, the live wire input end of the current detection controller and an input end of the heating signal control switch SA2, the other end of the heating signal control switch SA2 is connected to the P2 input end of the current detection controller, the three output ends of the current detection controller are respectively connected to the L1 alarm indicator light, the L2 alarm indicator light and the L3 alarm indicator light, the heating signal control switch SA2 is connected to the signal port of the digital display thermostat or the thermostat; 4 leads are set on the motor M, 2 of which are connected to the capacitor, and 2 wires are connected to the fan signal port inside the integrated electric control cabinet.

2. The electric heating pipe explosion-proof warning device according to claim 1, characterized in that: During factory inspection, adjust the voltage of the equipment to which the electric heating tube belongs to the rated voltage through the voltage regulator. When powered on, after running for a period of time to stabilize, detect the resistance value and current of the equipment, and set the detected resistance value and current value as the standard value.

3. The electric heating pipe explosion-proof warning device according to claim 2, characterized in that: When the air inlet of the fan device connected to the electric heating tube is blocked or the motor is stuck, the self-reset temperature rises to the set value, the self-reset thermostat is disconnected, and the AC contactor is disconnected. The fan device used to dissipate heat for the electric heating tube is delayed for a second time and then the power is cut off.

4. The electric heating pipe explosion-proof warning device according to claim 2, characterized in that: When the self-reset thermostat fails, the air inlet of the fan device connected to the electric heating tube is blocked or the motor is stuck, the temperature continues to rise. After the manual reset temperature rises to the set value of the manual reset thermostat, the manual reset thermostat is disconnected, and the AC contactor KM is disconnected, cutting off the power supply.

5. The electric heating pipe explosion-proof warning device according to claim 2, characterized in that: After the first power-on, the standard value of the circuit current is detected by three transformers. When any transformer detects that the current in the circuit is I≥standard value*K1, the corresponding alarm indicator light flashes every 3 seconds. The value of K1 is 1.2-2, and an alarm buzzer sounds. When the abnormality is eliminated, the power is turned off and reset after restart.

6. The electric heating pipe explosion-proof warning device according to claim 2, characterized in that: After the first power-on, the standard value of the circuit current is detected by three transformers. When any transformer detects that the current in the circuit is I≤standard value*K2, the corresponding alarm indicator light flashes every 3 seconds. The value of K2 is 0.3-0.8, and an alarm buzzer sounds. When the abnormality is eliminated, the power is turned off and reset after restart.

7. The electric heating pipe explosion-proof warning device according to any one of claims 1 to 6, characterized in that: Further including: The resistance sensor RH obtains the resistance value of the electric heating tube in real time; The on / off state of the fan and / or the on / off state of the contacts of the AC contactor are controlled according to the magnitude relationship between the resistance value and the resistance threshold.

8. The electric heating pipe early warning protection method according to claim 7, characterized in that: The controlling of the switching state of the cooling mechanism and / or the on / off of the contacts of the AC contactor according to the magnitude relationship between the resistance value and the resistance threshold value includes: If the resistance value is greater than the resistance threshold, the contacts of the AC contactor are controlled to be disconnected, and the fan is controlled to continue running for a preset time and then the power supply is cut off.

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