Central heating control system

Abstract

The utility model relates to the technical field of heating control, and discloses a central heating control system, which comprises a PLC (Programmable Logic Controller) control circuit which comprises a basic unit and an expansion unit, the basic unit comprises a main controller, a digital quantity processing module, an intermediate relay module and an electromagnetic valve control module; the input end of the main controller is connected with the digital quantity processing module, and the output end of the main controller is connected to the fan, the water pump and the electromagnetic valve control module through the intermediate relay module. The expansion unit comprises an input expansion module connected with the main controller, and a water temperature sensor, a gas sensor, a wind pressure sensor and a water pressure sensor which are respectively connected with the input expansion module. According to the utility model, the overload protection and automatic start-stop functions of the motor, the automatic on-off function of each electromagnetic valve, and the real-time monitoring function of outlet water temperature, gas concentration, wind pressure and water pressure can be realized, so that the automation degree, reliability and safety of the system are improved, and the safe and stable operation of the system is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of heating control, in particular to a centralized heating control system. Background Art

[0002] A central heating burner is a device that mixes fuel (such as gas, oil, etc.) with air in a certain proportion and then burns it. The main function of this device is to generate heat energy by burning fuel, thereby providing the required heat for the heating system.

[0003] The existing central heating burner control system mainly includes a microprocessor, the signal acquisition end of the microprocessor is connected to a temperature sensor, a pressure sensor and a flow sensor, and the signal control end of the microprocessor is connected to a circulating water pump and a fan. The control system can realize intelligent control of the central heating burner through the coordinated work of all sensors, microprocessors, circulating air pumps and fans. However, the control system, whose microprocessor is directly connected to the circulating water pump and the fan, cannot cut off the power in time when the circulating water pump and the fan are overloaded, and the overloaded current will impact the microprocessor, affecting the normal operation of the microprocessor and even paralyzing the entire control system. In addition, the control system cannot monitor the gas concentration in real time, and cannot promptly alarm when a gas leak occurs, which greatly affects the safety and reliability of the central heating equipment. Utility Model Content

[0004] The main purpose of the utility model is to provide a central heating control system, aiming to solve the technical problem that the existing central heating burner control system has unstable or unsafe operation.

[0005] To achieve the above object, the utility model provides a centralized heating control system, comprising: a PLC control circuit, wherein the PLC control circuit comprises a basic unit and an expansion unit;

[0006] The basic unit includes a main controller, a digital quantity processing module, an intermediate relay module and a solenoid valve control module; the input end of the main controller is connected to the digital quantity processing module, and the output end of the main controller is connected to the fan, the water pump and the solenoid valve control module respectively through the intermediate relay module; the solenoid valve control module includes an ignition gun solenoid valve, a high-pressure package solenoid valve, a low-fire solenoid valve, a high-fire solenoid valve, a water inlet solenoid valve and a water outlet solenoid valve, and each solenoid valve is respectively connected to an intermediate relay in the intermediate relay module;

[0007] The expansion unit comprises an input expansion module connected to the main controller, and a water temperature sensor, a gas sensor, a wind pressure sensor and a water pressure sensor respectively connected to the input expansion module.

[0008] Preferably, the digital quantity processing module includes a reset button, an emergency stop button, a flame detector, a water inlet valve control switch and a water outlet valve control switch, and the reset button, the emergency stop button, the flame detector, the water inlet valve control switch and the water outlet valve control switch are respectively connected to an input end of the main controller.

[0009] Preferably, the solenoid valve control module further includes a backup solenoid valve, and the backup solenoid valve is connected to an intermediate relay in the intermediate relay module.

[0010] Preferably, the PLC control circuit further includes an alarm unit; the alarm unit includes a buzzer, and the buzzer is connected to the main controller through the intermediate relay module.

[0011] Preferably, the central heating control system also includes a main circuit, which includes a power interface, a first thermal relay, a second thermal relay, an AC contactor, a frequency converter, a water pump, a fan, a switching power converter and a display; the second thermal relay, the AC contactor, the frequency converter and the display are all connected to the main controller; the input end of the first thermal relay is connected to the three-phase terminal of the power interface, the output end of the first thermal relay is respectively connected to the input end of the second thermal relay and the input end of the frequency converter, the output end of the second thermal relay is connected to the water pump through the AC contactor, the output end of the frequency converter is connected to the fan, the input end of the switching power converter is connected to the AC terminal of the power interface, and the output end of the switching power converter outputs a 24V DC power supply to power the display and the main controller.

[0012] Preferably, the main circuit further includes a third thermal relay, and the third thermal relay is connected between the A-phase terminal of the power interface and the switching power converter.

[0013] Preferably, the main circuit further comprises an indicator light, which is connected in parallel to the A-phase terminal and the neutral line terminal of the power interface.

[0014] Preferably, the main controller adopts an SR20 programmable controller.

[0015] Preferably, the input expansion module adopts an AE04 analog expansion module.

[0016] The above central heating control system has the following beneficial effects:

[0017] 1) The centralized heating control system of the utility model can realize the overload protection and automatic start and stop functions of the motor (water pump and fan) and the automatic switch function of each solenoid valve through the coordinated action of the main controller, digital quantity processing module, intermediate relay module and solenoid valve control module, thereby improving the automation, reliability and safety of the system and providing a strong guarantee for the safe and stable operation of the system;

[0018] 2) The centralized heating control system of the utility model can realize the real-time monitoring function of the outlet water temperature, gas concentration, wind pressure and water pressure through the cooperation of the main controller, input expansion module and various sensors, which further provides a strong guarantee for the safe, stable and efficient operation of the system;

[0019] 3) The centralized heating control system of the utility model can realize the energy-gathering secondary combustion of the burner through the coordinated action of the ignition gun solenoid valve, the high-pressure package solenoid valve, the low-fire solenoid valve, the high-fire solenoid valve, the water inlet solenoid valve and the water outlet solenoid valve. The energy-gathering secondary combustion can improve the completeness of combustion, improve heating efficiency, reduce energy consumption and reduce pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural block diagram of an embodiment of the central heating control system of the utility model;

[0021] Figure 2 This is a structural block diagram of another embodiment of the central heating control system of the utility model;

[0022] Figure 3 for Figure 1 Circuit diagram of the basic unit of the central heating control system;

[0023] Figure 4 for Figure 1 Circuit diagram of the extension unit of the central heating control system;

[0024] Figure 5 for Figure 1 Circuit diagram of the main circuit of the central heating control system. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] In one embodiment, the utility model provides a centralized heating control system, which can be used for energy-gathering secondary burners or centralized heating equipment. Among them, the energy-gathering secondary burner includes: an energy-gathering compression disc, a guide turbine disc, a guide diverter disc, a gas quantitative balancing disc and a cooling water jacket; the energy-gathering compression disc is fixedly mounted on the guide turbine disc, the guide turbine disc is mounted on the gas quantitative balancing disc, and the gas quantitative balancing disc is mounted in the cooling water jacket; the energy-gathering compression disc includes a compression disc body and an energy-gathering pressure ring mounted on the compression disc body; the guide turbine disc includes a turbine disc cavity and a water cooling ring arranged in the turbine disc cavity; the gas quantitative balancing disc includes a quantitative balancing disc base, a quantitative balancing disc cavity mounted on the quantitative balancing disc base, and a quantitative balancing disc cover mounted on the quantitative balancing disc cavity, and a gas balancing pipe is installed in the gas quantitative balancing disc; the energy-gathering compression disc, the guide turbine disc and the quantitative balancing disc cover form a combustion chamber, and a guide diverter disc is installed in the middle of the combustion chamber. The central heating equipment is the central heating equipment disclosed in patent document CN118687184A, including: a gas electric control system, a cooling system and a burner; the gas electric control system includes a gas pipeline and an ignition gun; the cooling system includes a circulating water pipeline, a flue pipe, a primary heat exchanger, a secondary heat exchanger and an air supply pipeline; the circulating water pipeline includes an inlet pipeline and an outlet pipeline, and the cold water in the inlet pipeline enters the burner through the secondary heat exchanger, cools the burner and then circulates to the primary heat exchanger, and hot water flows out through the outlet pipeline; the flue pipe is connected to the top of the primary heat exchanger through the secondary heat exchanger, and the bottom of the primary heat exchanger is connected to the secondary burner; the ignition gun is arranged on one side of the bottom of the primary heat exchanger, and is respectively connected to the gas pipeline and the air supply pipeline.

[0027] refer to Figure 1 , Figure 3 and Figure 4 The central heating control system provided by the utility model includes: a PLC control circuit, the PLC control circuit includes a basic unit and an expansion unit; wherein the basic unit includes a main controller U1, a digital quantity processing module T1, an intermediate relay module T2 and a solenoid valve control module T3; the input end of the main controller U1 is connected to the digital quantity processing module T1, and the output end of the main controller U1 is respectively connected to the external fan M2, the water pump M1 and the solenoid valve control module T3 through the intermediate relay module T2; the solenoid valve control module T3 includes an ignition gun solenoid valve YA1, a high-pressure package solenoid valve YA2, a small fire solenoid valve YA3, a large fire solenoid valve YA4, a water inlet solenoid valve YA5 and a water outlet solenoid valve YA6, and each solenoid valve is respectively connected to an intermediate relay in the intermediate relay module T2; the expansion unit includes an input expansion module U2 connected to the main controller U1, and a water temperature sensor R1, a gas sensor R2, a wind pressure sensor R3 and a water pressure sensor R4 respectively connected to the input expansion module U2.

[0028] In this embodiment, the digital quantity processing module T1 may include multiple button switches, multiple soft switches, switch quantity type flame detectors and thermal relays, etc. The digital quantity processing module T1 is used to output switch quantity signals and send them to the main controller U1.

[0029] The intermediate relay module T2 includes several intermediate relays, each of which is mainly composed of a coil and a contact. The intermediate relay module T2 is used to isolate strong electricity to prevent strong electricity from directly entering the main controller U1, thereby protecting the safe use of the main controller U1, and the intermediate relay amplifies and converts the control signal output by the main controller U1 to drive the load (such as a motor, solenoid valve, etc.) connected to the main controller U1. It can be understood that the fan M2, the water pump M1 and each solenoid valve in the solenoid valve control module T3 in the central heating control system are respectively connected to a certain intermediate relay in the intermediate relay module T2.

[0030] The solenoid valve control module T3 includes but is not limited to the ignition gun solenoid valve YA1, the high-pressure package solenoid valve YA2, the low-fire solenoid valve YA3, the high-fire solenoid valve YA4, the water inlet solenoid valve YA5 and the water outlet solenoid valve YA6, etc., wherein the ignition gun solenoid valve YA1 is used to control the ignition gun in the central heating equipment to perform electric spark ignition, the high-pressure package solenoid valve YA2 is used to control the high-pressure package in the central heating equipment to perform pulse ignition, the low-fire solenoid valve YA3 is used to control the gas branch connected to the ignition gun in the central heating equipment to open or close, the high-fire solenoid valve YA4 is used to control the gas branch connected to the burner in the central heating equipment to open or close, the water inlet solenoid valve YA5 is used to control the water inlet pipeline in the central heating equipment to open or close, and the water outlet solenoid valve YA6 is used to control the water outlet pipeline in the central heating equipment to open or close. Preferably, each solenoid valve in the solenoid valve control module T3 is mainly composed of a solenoid valve coil, an iron core, a valve body and a valve cover.

[0031] The expansion unit includes an input expansion module U2, and a water temperature sensor R1, a gas sensor R2, a wind pressure sensor R3 and a water pressure sensor R4 which are respectively connected to the input expansion module U2, wherein the water temperature sensor R1 is used to measure the water temperature in the water outlet pipe, the gas sensor R2 is used to measure the gas concentration at the connection between the gas pipe and the central heating equipment, the wind pressure sensor R3 is used to measure the wind pressure output by the fan M2, and the water pressure sensor R4 is used to measure the water pressure output by the water pump M1. The input expansion module U2 is used to convert the measured sensor data such as water temperature, gas concentration, wind pressure and water pressure into digital signals, and send them to the main controller U1.

[0032] The main controller U1 can be a programmable logic controller, which mainly includes an input terminal, an output terminal and an expansion terminal, etc. The input terminal of the main controller U1 is connected to the output terminal of the digital quantity processing module T1, the output terminal of the main controller U1 is connected to the solenoid valve control module T3 through the intermediate relay module T2, and the expansion terminal of the main controller U1 is connected to the input expansion module U2. The main controller U1 is used to control the start and stop of the water pump M1 and the fan M2; obtain the switch signal sent by the digital quantity processing module T1, perform corresponding control operations (such as reset, emergency stop operation, etc.) according to the switch signal, or generate a signal corresponding to the water outlet / water inlet solenoid valve according to the switch signal. The control module U1 generates a corresponding control signal; obtains the sensor data (the sensor data includes the outlet water temperature, gas concentration, wind pressure and water pressure) sent by the input expansion module U2, and generates a control signal corresponding to the ignition gun / high-pressure package / small fire / high fire solenoid valve according to the sensor data and the preset control logic; transmits the control signal to the corresponding solenoid valve in the solenoid valve control module T3 through the intermediate relay module T2 to realize the control of the switching action of each solenoid valve; and when the gas concentration is abnormal, that is, the gas concentration exceeds the preset gas alarm threshold, generates a gas leakage alarm information and sends it to the display LCD1 connected to the main controller U1.

[0033] Preferably, the control logic in the main controller U1 is pre-set as follows: when the wind pressure and the water pressure are normal, that is, the wind pressure reaches the preset wind pressure threshold, and the water pressure reaches the preset water pressure threshold, a control signal corresponding to the ignition gun solenoid valve YA1 is generated to start the ignition gun, and at the same time, a control signal corresponding to the small fire solenoid valve YA3 is generated to open the small fire solenoid valve YA3 for a combustion; the flame detection signal fed back by the flame detector is detected in real time. If a flame detection signal is detected, the internal timer is started to start timing. When the timing time of the timer reaches the preset time threshold, it is determined that one combustion is completed, and a control signal corresponding to the high-pressure package solenoid valve YA2 is generated to start the high-pressure package, and at the same time, a control signal corresponding to the high-fire solenoid valve YA4 is generated to open the high-fire solenoid valve YA4 for a secondary combustion; when it is detected that the water temperature does not reach the preset temperature threshold, a control signal corresponding to the high-fire solenoid valve YA4 is generated to increase the opening degree of the high-fire solenoid valve YA4, thereby increasing the gas flow entering the burner.

[0034] In summary, the centralized heating control system of this embodiment has the following beneficial effects:

[0035] 1) The centralized heating control system of this embodiment can realize the overload protection and automatic start and stop functions of the motor (water pump and fan) and the automatic switch function of each solenoid valve through the coordinated action of the main controller U1, the digital quantity processing module T1, the intermediate relay module T2 and the solenoid valve control module T3, thereby improving the automation, reliability and safety of the system and providing a strong guarantee for the safe and stable operation of the system;

[0036] 2) The centralized heating control system of this embodiment can realize the real-time monitoring function of outlet water temperature, gas concentration, wind pressure and water pressure through the cooperation of the main controller U1, the input expansion module U2 and various sensors, further providing a strong guarantee for the safe, stable and efficient operation of the system;

[0037] 3) The centralized heating control system of this embodiment can realize the energy-gathering secondary combustion of the burner through the coordinated action of the ignition gun solenoid valve YA1, the high-pressure package solenoid valve YA2, the low-fire solenoid valve YA3, the high-fire solenoid valve YA4, the water inlet solenoid valve YA5 and the water outlet solenoid valve YA6. The energy-gathering secondary combustion can improve the completeness of combustion, improve heating efficiency, reduce energy consumption and reduce pollution.

[0038] In a preferred embodiment, reference Figure 3 The intermediate relay module T2 includes a first intermediate relay KA1, a second intermediate relay KA2, a third intermediate relay KA3, a fourth intermediate relay KA4, a fifth intermediate relay KA5, a sixth intermediate relay KA6, a seventh intermediate relay KA7, an eighth intermediate relay KA8 and a ninth intermediate relay KA9.

[0039] In this embodiment, the coil control ends of the first intermediate relay KA1, the second intermediate relay KA2, the third intermediate relay KA3, the fourth intermediate relay KA4, the fifth intermediate relay KA5, the sixth intermediate relay KA6, the seventh intermediate relay KA7, the eighth intermediate relay KA8 and the ninth intermediate relay KA9 are respectively connected to an output end of the main controller U1, the contact output end of the first intermediate relay KA1 is connected to the ignition gun solenoid valve YA1, the contact output end of the second intermediate relay KA2 is connected to the high-voltage package solenoid valve YA2, the contact output end of the third intermediate relay KA3 is connected to the low-fire solenoid valve YA3, and the contact output end of the fourth intermediate relay KA4 is connected to the low-fire solenoid valve YA4. The output end is connected to the high fire solenoid valve YA4, the contact output end of the fifth intermediate relay KA5 is connected to the water inlet solenoid valve YA5, the contact output end of the sixth intermediate relay KA6 is connected to the water outlet solenoid valve YA6, the contact output end of the seventh intermediate relay KA7 is connected to the AC contactor KM1 for controlling the water pump M1, the contact output end of the eighth intermediate relay KA8 is connected to the frequency converter V1 for controlling the fan M2, the contact output end of the ninth intermediate relay KA9 is connected to the buzzer H1 in the alarm unit, and the common ends of the coils of the intermediate relays KA1-KA9 are all connected to the negative terminal N24 of the DC power supply, and the contact input ends are all connected to the positive terminal 220L of the AC power supply.

[0040] Further, refer to Figure 3 The intermediate relay module T2 also includes a spare intermediate relay KAZ.

[0041] It can be understood that the standby intermediate relay KAZ is set according to demand, the coil control end of the standby intermediate relay KAZ is connected to an output end of the main controller U1, the contact output end is connected to the standby solenoid valve YAZ, the coil common end is connected to the negative end N24 of the DC power supply, and the contact input end is connected to the positive end 220L of the AC power supply.

[0042] In a preferred embodiment, reference Figure 3 The digital quantity processing module T1 includes a reset button SB1, an emergency stop button SB2, a flame detector S1, a water inlet valve control switch S2 and a water outlet valve control switch S3, and the reset button SB1, the emergency stop button SB2, the flame detector S1, the water inlet valve control switch S2 and the water outlet valve control switch S3 are respectively connected to an input end of the main controller U1.

[0043] In this embodiment, the digital quantity processing module T1 includes but is not limited to a reset button SB1, an emergency stop button SB2, a flame detector S1, a water inlet valve control switch S2, a water outlet valve control switch S3, and a thermal relay QF2. Among them, the water inlet valve control switch S2 and the water outlet valve control switch S3 are both soft switches set in the display LCD1, the water inlet valve control switch S2 may include a water inlet valve opening switch S2a and a water inlet valve closing switch S2b, the water outlet valve control switch S3 may include a water outlet valve opening switch S2a and a water outlet valve closing switch S2b, and the water inlet / water outlet valve opening switch is in a low level state by default, and the water inlet / water outlet valve closing switch is in a high level state by default. It should be noted that in other embodiments, the water inlet / water outlet valve control switch may be a switch, in which case the water inlet / water outlet valve control switch is in a closed state by default, and when the water inlet / water outlet valve control switch is triggered, it is converted from the default closed state to the open state.

[0044] Each switch in the digital quantity processing module T1 sends a reset signal to the main controller U1 when the reset button SB is pressed, so that the main controller U1 performs a reset operation; sends an emergency stop signal to the main controller U1 when the emergency stop button SB2 is pressed, so that the main controller U1 performs an emergency stop operation; sends a flame detection signal to the main controller U1 when the flame detector S1 detects a flame, so that the main controller U1 starts the built-in timer to start timing; sends a high-level signal to the main controller U1 when the water inlet / outlet valve opening switch is triggered, so that the main controller U1 sends a valve opening control signal to the water inlet / outlet solenoid valve; when the water inlet / outlet valve closing switch is in the default high-level state, the main controller U1 sends a valve closing control signal to the water inlet / outlet solenoid valve; and sends an overload protection signal to the main controller U1 when the thermal relay QF2 is triggered due to overload, so that the main controller U1 performs corresponding protection measures, such as stopping the motor operation or issuing a warning signal.

[0045] It can be understood that the central heating control system of this embodiment, whose digital quantity processing module T1 includes a reset button SB1, an emergency stop button SB2, a flame detector S1, a water inlet valve control switch S2, a water outlet valve control switch S3 and a thermal relay QF2, can realize the automatic reset function, emergency stop function, flame detection function, automatic valve switching function and overload protection function of the main controller U1.

[0046] Further, refer to Figure 4 The solenoid valve control module T3 also includes a spare solenoid valve YAZ, which is connected to an intermediate relay in the intermediate relay module T2.

[0047] In this embodiment, the standby solenoid valve YAZ is set according to demand to avoid affecting the automatic switch valve function due to damage to the water inlet / outlet solenoid valve.

[0048] In a preferred embodiment, reference Figure 4 The PLC control circuit also includes an alarm unit; the alarm unit includes a buzzer H1, and the buzzer is connected to the main controller U1 through the intermediate relay module T2.

[0049] In this embodiment, the PLC control circuit includes but is not limited to a basic unit, an expansion unit and an alarm unit, etc. The alarm unit includes a buzzer H1, one end of the buzzer H1 is connected to a certain intermediate relay contact in the intermediate relay module T2, and the other end is connected to the negative terminal N24 of the DC power supply. At this time, the main controller U1 is also used to generate a control signal corresponding to the buzzer H1 when the switch signal output by the digital quantity processing module T1 is not detected, or when the sensor data is detected to be abnormal, so as to start the buzzer H1 to alarm. For example, when the main controller U1 detects that the gas concentration is abnormal, that is, the gas concentration exceeds the gas alarm threshold, the main controller U1 sends a first type of control signal and transmits it to the alarm unit through the intermediate relay module T2. The alarm unit makes the buzzer H1 emit a "woohoo" sound to alarm the gas leak according to the first type of control signal; for another example, when the main controller U1 fails to detect the flame detection signal after timeout, the main controller U1 sends a second type of control signal and transmits it to the alarm unit through the intermediate relay module T2. The alarm unit makes the buzzer H1 emit a "didi" sound to alarm the flame detector failure according to the second type of control signal.

[0050] It can be understood that the centralized heating control system of this embodiment can realize functions such as gas leakage alarm, sensor data abnormality alarm, sensor fault alarm and flame detector fault alarm by setting up the main controller U1, digital quantity processing module T1, input expansion module U2 and various sensors.

[0051] For further reference, Figure 2 , Figure 3 and Figure 5 Another embodiment of the utility model provides a centralized heating control system based on the above Figure 1 In the embodiment shown, the central heating control system also includes a main circuit, which includes a power supply interface J1, a first thermal relay QF1, a second thermal relay QF2, an AC contactor KM1, a frequency converter V1, a water pump M1, a fan M2, a switching power converter V2 and a display LCD1; the second thermal relay QF2, the AC contactor KM1, the frequency converter V1 and the display LCD1 are all connected to the main controller U1; the input end of the first thermal relay QF1 is connected to the three-phase terminal of the power supply interface J1, and the second thermal relay QF2 is connected to the three-phase terminal of the power supply interface J1. The output end of a thermal relay QF1 is respectively connected to the input end of the second thermal relay QF2 and the input end of the frequency converter V1, the output end of the second thermal relay QF2 is connected to the water pump M1 through the AC contactor KM1, the output end of the frequency converter V1 is connected to the fan M2, the input end of the switching power converter V2 is respectively connected to the AC connection terminal of the power interface J1, and the output end of the switching power converter V2 outputs a 24V DC power supply to power the display LCD1 and the main controller U1.

[0052] In this embodiment, the central heating control system includes a PLC control circuit and a main circuit, and the PLC control circuit can be used to control the main circuit, which includes but is not limited to a power interface J1, a first thermal relay QF1, a second thermal relay QF2, an AC contactor KM1, a frequency converter V1, a water pump M1, a fan M2, a switching power converter V2, and a display LCD1, etc. Among them, the power interface J1 includes an A-phase terminal, a B-phase terminal, a C-phase terminal, and a neutral terminal, which are used to connect a three-phase four-wire AC power supply, and the A-phase terminal, the B-phase terminal, and the C-phase terminal constitute a three-phase terminal, and the A-phase terminal and the neutral terminal constitute a 220V AC terminal.

[0053] The thermal relay includes a thermal element, a contact system (the contact system consists of normally open and normally closed contacts), an input terminal and an output terminal connected to the thermal element respectively, and a contact terminal connected to the contact system. The AC contactor KM1 includes a main contact, an auxiliary contact and an electromagnetic coil. The input terminal of the second thermal relay QF2 is connected to the output terminal of the first thermal relay QF1, and the output terminal of the second thermal relay QF2 is connected to the water pump M1 through the AC contactor KM1. The normally open contact terminal of the second thermal relay QF2 is connected to an input terminal of the main controller U1, and the electromagnetic coil of the AC contactor KM1 is connected to an output terminal of the main controller U1 through an intermediate relay (such as the seventh intermediate relay KA7) of the intermediate relay module T2. The second thermal relay QF2 is used to monitor the current during the operation of the water pump M1 through the thermal element. When the current exceeds the set current value, the control circuit of the water pump M1 is cut off by changing the state of the contact, thereby achieving overload protection.

[0054] The frequency converter V1 is a three-phase frequency converter, including an input terminal, an output terminal and a control circuit terminal. The input terminal of the frequency converter V1 is connected to the output terminal of the first thermal relay QF1, the output terminal of the frequency converter V1 is connected to the fan M2, and the control circuit terminal of the frequency converter V1 is connected to an output terminal of the main controller U1 through an intermediate relay (such as the eighth intermediate relay KA8) of the intermediate relay module T2. The frequency converter V1 is used to drive the start and stop of the fan M2 under the control of the main controller U1.

[0055] The input end of the switching power converter V2 is connected to the AC terminal, and the output end is connected to the components of the central heating control system that need to be powered, such as the display LCD1, the main controller U1 and the intermediate relay module T2, etc. The switching power converter V2 is used to convert the 220V AC power supply into a 24V DC power supply. It should be noted that the input end of the switching power converter V2 includes the AC power positive terminal 220L and the AC power negative terminal 220N, and the output end of the switching power converter V2 includes the DC power positive terminal P24 and the DC power negative terminal N24.

[0056] The display LCD1 is provided with a plurality of soft switches, such as the water inlet valve control switch S2 and the water outlet valve control switch S3. The display LCD1 is connected to the main controller U1 via serial port communication. The display LCD1 can display the sensor data, abnormal alarm information and equipment failure information transmitted by the main controller U1 in real time.

[0057] It can be understood that the centralized heating control system of this embodiment, by setting up a main circuit and a PLC control circuit for controlling the main circuit, can achieve overload protection and automatic start and stop control of the water pump M1 and the fan M2, thereby improving the operating stability of the entire system. In addition, through the switching power converter V2 in the main circuit, a stable DC power supply can be provided to the system to ensure the normal operation of the system.

[0058] In a preferred embodiment, reference Figure 2 and Figure 5 The main circuit also includes a third thermal relay QF3, and the third thermal relay QF3 is connected between the A-phase terminal of the power interface J1 and the switching power converter V2.

[0059] In this embodiment, the contacts of the third thermal relay QF3 are connected in series between the A-phase terminal of the power interface J1 and the AC power positive terminal 220L of the switching power converter. The third thermal relay QF3 can perform overload protection on the switching power converter V2 and other devices connected to the switching power converter V2, thereby ensuring the safe and stable operation of the entire system.

[0060] In a preferred embodiment, reference Figure 2 and Figure 5 The main circuit also includes an indicator light H2, which is connected in parallel to the A-phase terminal and the neutral line terminal of the power interface J1.

[0061] In this embodiment, the indicator light H2 is connected in parallel to the A-phase terminal and the neutral terminal of the power interface J1. The indicator light H2 is used to indicate whether the entire system is operating normally. If the indicator light H2 is on, it means that the system is operating normally, otherwise it means that the system is operating abnormally.

[0062] In a preferred embodiment, reference Figure 2 and Figure 3 The main controller U1 adopts SR20 programmable controller.

[0063] Among them, the SR20 programmable controller can include an input terminal, an output terminal, a communication terminal, an AC power terminal, a DC power terminal and an expansion port, etc. Optionally, the input terminal of the SR20 programmable controller is respectively connected to the reset button SB1, the emergency stop button SB2, the flame detector S1, the water inlet valve opening switch S2a, the water inlet valve closing switch S2b, the water outlet valve opening switch S2a, the water outlet valve closing switch S2b and the contact of the second thermal relay QF2; the output terminal of the SR20 programmable controller is respectively connected to the solenoid valves YA6-YA6 in the solenoid valve control module T3 through the intermediate relays KA1-KA6 in the intermediate relay module T2, connected to the electromagnetic coil of the AC contactor KM1 through the intermediate relay KA7 in the intermediate relay module T2, connected to the control circuit terminal of the frequency converter V1 through the intermediate relay KA8 in the intermediate relay module T2, and connected to the buzzer H1 through the intermediate relay KA9 in the intermediate relay module T2. It can be understood that this embodiment is conducive to improving the automation, reliability and safety of the entire system through the SR20 programmable controller.

[0064] In a preferred embodiment, reference Figure 2 and Figure 3 The input expansion module U2 adopts AE04 analog expansion module.

[0065] It is understandable that the AE04 analog expansion module of this embodiment can be directly inserted into the expansion port of the SR20 programmable controller to send the collected sensor data such as outlet water temperature, gas concentration, wind pressure and water pressure to the main controller U1 to realize the real-time monitoring function of sensor data.

[0066] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a device, product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such device, product or system. In the absence of more restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the device, product or system including the element.

[0067] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A central heating control system, characterized in that: The central heating control system comprises: a PLC control circuit, wherein the PLC control circuit comprises a basic unit and an expansion unit; The basic unit includes a main controller, a digital quantity processing module, an intermediate relay module and a solenoid valve control module; the input end of the main controller is connected to the digital quantity processing module, and the output end of the main controller is connected to the fan, the water pump and the solenoid valve control module respectively through the intermediate relay module; the solenoid valve control module includes an ignition gun solenoid valve, a high-pressure package solenoid valve, a low-fire solenoid valve, a high-fire solenoid valve, a water inlet solenoid valve and a water outlet solenoid valve, and each solenoid valve is respectively connected to an intermediate relay in the intermediate relay module; The expansion unit comprises an input expansion module connected to the main controller, and a water temperature sensor, a gas sensor, a wind pressure sensor and a water pressure sensor respectively connected to the input expansion module.

2. The central heating control system according to claim 1, characterized in that: The digital quantity processing module includes a reset button, an emergency stop button, a flame detector, a water inlet valve control switch and a water outlet valve control switch, and the reset button, the emergency stop button, the flame detector, the water inlet valve control switch and the water outlet valve control switch are respectively connected to an input end of the main controller.

3. The central heating control system according to claim 1, characterized in that: The solenoid valve control module further comprises a spare solenoid valve, and the spare solenoid valve is connected to an intermediate relay in the intermediate relay module.

4. The central heating control system according to claim 1, characterized in that: The PLC control circuit also includes an alarm unit; the alarm unit includes a buzzer, and the buzzer is connected to the main controller through the intermediate relay module.

5. The central heating control system according to claim 1, characterized in that: The centralized heating control system also includes a main circuit, which includes a power interface, a first thermal relay, a second thermal relay, an AC contactor, a frequency converter, a water pump, a fan, a switching power converter and a display; the second thermal relay, the AC contactor, the frequency converter and the display are all connected to the main controller; the input end of the first thermal relay is connected to the three-phase terminal of the power interface, the output end of the first thermal relay is respectively connected to the input end of the second thermal relay and the input end of the frequency converter, the output end of the second thermal relay is connected to the water pump through the AC contactor, the output end of the frequency converter is connected to the fan, the input end of the switching power converter is connected to the AC terminal of the power interface, and the output end of the switching power converter outputs a 24V DC power supply to power the display and the main controller.

6. The central heating control system according to claim 5, characterized in that: The main circuit also includes a third thermal relay, which is connected between the A-phase terminal of the power interface and the switching power converter.

7. The central heating control system according to claim 6, characterized in that: The main circuit also includes an indicator light, which is connected in parallel to the A-phase terminal and the neutral line terminal of the power interface.

8. The central heating control system according to claim 1, characterized in that: The main controller adopts SR20 programmable controller.

9. The central heating control system according to claim 8, characterized in that: The input expansion module adopts AE04 analog expansion module.

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