Dual fuel gas burner and method of controlling the same

Abstract

The application discloses a gas dual-purpose stove, which comprises a combustion heat exchange device (1), a burner (13), a heat exchanger (2), a heat exchange pipeline (3), a heating water inlet pipe (4a) and a heating water outlet pipe (4b), a domestic water inlet pipe (5a) and a domestic water outlet pipe (5b), and a delivery pump (6), characterized in that the combustion heat exchange device (1) further comprises a smoke temperature sensor (14), and the gas dual-purpose stove is provided with a controller which can receive signals collected by the smoke temperature sensor (14) and adjust a proportional valve (1111) and control the opening and closing of valves on a second heat exchange section (32) and the heating water outlet pipe (4b). The application further discloses a control method of the gas dual-purpose stove. Compared with the prior art, the gas dual-purpose stove is convenient to adjust the smoke temperature to a reasonable range.

Description

Technical Field

[0001] This invention relates to the field of heating equipment technology, specifically to a gas-fired dual-purpose furnace and its control method. Background Technology

[0002] Currently, some residential buildings are equipped with underfloor heating or other hydrothermal heating systems. In these buildings, in addition to domestic water supply, an extra water supply is needed to power the corresponding hydrothermal heating equipment. Therefore, ordinary gas water heaters cannot simultaneously supply hot water for domestic use and heating water for the hydrothermal equipment. A dual-purpose boiler is required to supply both hot water for domestic use and heating water for the equipment.

[0003] In existing dual-purpose boilers, a three-way valve is used to switch between internal and external circulation: In heating mode, the boiler switches to external circulation, and the heat exchange pipes are connected to the heating pipes. Under the action of the circulation pump, the water in the heat exchange pipes is heated by the combustion heat exchange device and then discharged into the heating pipes. Hot water flows through each room through the external circulation, thus achieving heating. In domestic hot water mode, the boiler switches to internal circulation, and the heat exchange pipes themselves form a circulation loop. Under the action of the circulation pump, hot water exchanges heat with the domestic water pipes as it flows through the heat exchanger, thus achieving the supply of domestic hot water. At this time, the heat exchange pipes are not connected to the heating pipes, the external circulation is interrupted, the water in the heating pipes is stagnant, and heating automatically stops until the use of domestic hot water ends. For the specific structure, please refer to the applicant's earlier patent application number CN201710624991.4 (publication number CN108061375A), Chinese invention patent "A Dual-Purpose Boiler Working System".

[0004] The combustion heat exchange device mainly includes a heat exchanger, a burner for supplying heat to the heat exchanger, and a fan for supplying air to the burner and exhausting flue gas.

[0005] However, currently available dual-purpose furnaces can only indirectly monitor flue gas discharge status through wind pressure sensors, and cannot accurately detect flue gas temperature. Some failure modes cannot be accurately identified, and protection is only activated when abnormal conditions are severe or damage occurs. Thus, on the one hand, there is no monitoring function for excessively high or low flue gas temperatures, and some failure modes cannot be prevented in advance; on the other hand, there are no active control and protection measures, and the only option is to shut down for protection, affecting usability. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide a gas-fired dual-purpose furnace that allows for easy adjustment of flue gas temperature to a reasonable range, in light of the current state of the prior art.

[0007] The second technical problem to be solved by the present invention is to provide a control method for the above-mentioned gas-fired dual-purpose furnace.

[0008] The technical solution adopted by the present invention to solve the first technical problem mentioned above is: a gas-fired dual-purpose furnace, comprising:

[0009] A combustion heat exchange device includes an inner shell and a heat exchanger and a burner disposed within the inner shell. The heat exchanger has a heat exchange channel inside, and the burner is used to supply heat to the heat exchanger.

[0010] The heat exchanger has internal hot water channels and cold water channels that exchange heat with each other;

[0011] The heat exchange pipe includes a first heat exchange section and a second heat exchange section connected in sequence. At least part of the first heat exchange section passes through the heat exchange channel of the heat exchanger, and at least part of the second heat exchange section passes through the hot water channel of the heat exchanger.

[0012] The heating inlet pipe and the heating outlet pipe are respectively connected to the two ends of the first heat exchange section, and are respectively used to connect to the two ends of the external heating pipeline.

[0013] The domestic water inlet pipe and the domestic water outlet pipe are respectively connected to both ends of the cold water passage of the heat exchanger; and

[0014] A delivery pump is installed on the first heat exchange section.

[0015] Valves are installed on both the second heat exchange section and the heating water outlet pipe to ensure that the dual-purpose boiler has at least two states:

[0016] In the first state, the second heat exchange section is connected, and the heating outlet pipe is disconnected.

[0017] In the second state, the second heat exchange section is disconnected, and the heating outlet pipe is connected.

[0018] The feature is that the combustion heat exchange device further includes a flue gas temperature sensor for monitoring the flue gas temperature inside the inner shell, and a gas pipeline for supplying gas to the burner is connected to the inner shell, and a proportional valve for adjusting the amount of gas is installed on the gas pipeline.

[0019] The gas-fired boiler has a controller. The flue gas temperature sensor, the proportional valve, and the valves on the second heat exchange section and the heating water outlet pipe are all electrically connected to the controller, so that the controller can receive the signal collected by the flue gas temperature sensor and adjust the proportional valve and control the opening and closing of the valves on the second heat exchange section and the heating water outlet pipe.

[0020] To facilitate complete combustion in the burner, the combustion heat exchange device further includes an outer shell located outside the inner shell. The inner wall of the outer shell and the outer wall of the inner shell have a sandwich layer. The inner shell has an air supply hole for connecting the inner cavity of the inner shell and the sandwich layer, and the inner shell is connected to an exhaust pipe for supplying flue gas. The outer shell is connected to an air supply pipe for supplying air. A fan for supplying air to the burner and exhausting flue gas is installed inside the inner shell.

[0021] In order to preheat the cold air and cool the high-temperature flue gas, the air supply pipe is at least partially fitted around the outer periphery of the exhaust pipe.

[0022] In order to indirectly monitor the exhaust status, the combustion heat exchange device also includes a wind pressure sensor for monitoring the wind pressure inside the exhaust duct.

[0023] To facilitate the installation of valves on the second heat exchange section and the heating outlet pipe, the second heat exchange section and the heating outlet pipe share the same three-way valve. The three-way valve has an inlet end, a first outlet end and a second outlet end. The inlet end of the three-way valve is connected to the first heat exchange section, the first outlet end of the three-way valve is connected to the second heat exchange section, and the second outlet end of the three-way valve is connected to the heating outlet pipe.

[0024] To facilitate pressure relief in the heating pipeline, a pressure relief valve is installed on the heat exchange pipeline or heating inlet pipe.

[0025] To facilitate the replenishment of water flow in the heating pipeline, a water replenishment pipe is connected between the domestic water inlet pipe and the heating water inlet pipe or the heating water outlet pipe. A water replenishment valve is installed on the water replenishment pipe to control the opening and closing of the water replenishment pipe.

[0026] To facilitate the containment and replenishment of the expansion and contraction of the circulating water, an expansion tank is connected to the heat exchange pipe or heating inlet pipe for containing and replenishing the expansion and contraction of the circulating water in the circulation loop.

[0027] The technical solution adopted by the present invention to solve the second technical problem mentioned above is: a control method for the above-mentioned gas-fired dual-purpose furnace, characterized by comprising the following steps:

[0028] (1) The smoke temperature sensor monitors the smoke temperature T inside the inner shell and transmits the collected signal to the controller;

[0029] (2) The controller determines whether the smoke temperature T is greater than the set value Tmax or less than the set value Tmin:

[0030] If the flue gas temperature T is greater than the set value Tmax, the controller adjusts the proportional valve to reduce the gas supply.

[0031] If the flue gas temperature T is less than the set value Tmin, and the gas-fired dual-purpose boiler is currently in the first state, the controller adjusts the proportional valve to increase the gas supply.

[0032] If the flue gas temperature T is less than the set value Tmin, and the gas-fired boiler is currently in the second state, the controller controls the valves on the second heat exchange section and the heating water outlet pipe to switch the gas-fired boiler to the first state or / and adjusts the proportional valve to increase the gas supply.

[0033] In order to avoid further damage, in step (2), if the flue gas temperature T is always greater than the set value Tmax or less than the set value Tmin after adjusting the proportional valve for a period of time, it can be determined that the heat exchanger is blocked and fails. The controller immediately shuts off the gas proportional valve and prompts for fault maintenance.

[0034] Compared with the prior art, the advantages of the present invention are as follows: by setting a flue gas temperature sensor to monitor the flue gas temperature inside the inner shell, and electrically connecting the flue gas temperature sensor, the proportional valve, and the valves on the second heat exchange section and the heating water outlet pipe to the controller, the controller can monitor abnormal flue gas temperature through the flue gas temperature sensor, and quickly adjust the flue gas temperature to a reasonable range through the proportional valve on the gas pipeline and the valves on the second heat exchange section and the heating water outlet pipe, so as to avoid extreme abnormal situations in advance, thereby protecting the machine and extending its life. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of an embodiment of the gas-fired dual-purpose furnace of the present invention (arrows indicate the direction of airflow);

[0036] Figure 2 for Figure 1 A schematic diagram of the structure of a dual-fuel gas boiler in its first state (arrows indicate the direction of water flow);

[0037] Figure 3 for Figure 1 A schematic diagram of the structure of a dual-fuel gas boiler in its second state (arrows indicate the direction of water flow). Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0039] like Figures 1 to 3 The image shows a preferred embodiment of the gas-fired dual-purpose boiler of the present invention. The gas-fired dual-purpose boiler includes a combustion heat exchange device 1, a heat exchanger 2, a heat exchange pipe 3, a heating water inlet pipe 4a, a heating water outlet pipe 4b, a domestic water inlet pipe 5a, a domestic water outlet pipe 5b, a delivery pump 6, and a three-way valve 7.

[0040] The combustion heat exchange device 1 includes an inner shell 11, a heat exchanger 12, a burner 13, a flue gas temperature sensor 14, an outer shell 15, a fan 16, and a wind pressure sensor 17. The heat exchanger 12, the burner 13, and the fan 16 are located inside the inner shell 11, and the outer shell 15 is located outside the inner shell 11. There is a sandwich 151 between the inner wall of the outer shell 15 and the outer wall of the inner shell 11.

[0041] Specifically, the bottom of the inner shell 11 is connected to a gas pipe 111 for supplying gas to the burner 13, and a proportional valve 1111 for adjusting the amount of gas is installed on the gas pipe 111; the bottom wall of the inner shell 11 has a plurality of gas supply holes 112 for connecting the inner cavity of the inner shell 11 and the interlayer 151; the top of the inner shell 11 is connected to a flue pipe 113 for supplying flue gas.

[0042] The heat exchanger 12 is located in the middle of the inner shell 11, and has heat exchange channels inside.

[0043] The burner 13 is located in the lower part inside the inner shell 11 and is used to supply heat to the heat exchanger 12;

[0044] The smoke temperature sensor 14 is installed on the upper part of the inner shell 11 to monitor the smoke temperature inside the inner shell 11.

[0045] The top of the outer casing 15 is connected to an air supply pipe 152 for replenishing air. The air supply pipe 152 is sleeved on the outer periphery of the exhaust pipe 113 and there is a gap between the two. In this way, the cold air in the air supply pipe 152 can fully exchange heat with the high temperature flue gas in the exhaust pipe 113, thereby preheating the cold air while cooling the high temperature flue gas.

[0046] The fan 16 is located at the inlet of the flue gas duct 113 and is used to supply air to the burner 13 and exhaust the flue gas.

[0047] The wind pressure sensor 17 is installed at the inlet of the smoke exhaust duct 113 to monitor the wind pressure inside the smoke exhaust duct 113.

[0048] The heat exchanger 2 has a hot water channel and a cold water channel that exchange heat with each other.

[0049] The heat exchange pipe 3 is a circulating pipe, including a first heat exchange section 31 and a second heat exchange section 32 connected in sequence. Specifically, the first heat exchange section 31 passes through the heat exchange channel of the heat exchanger 12, and the second heat exchange section 32 passes through the hot water channel of the heat exchanger 2.

[0050] Heating inlet pipe 4a and heating outlet pipe 4b are respectively connected to the inlet and outlet ends of the first heat exchange section 31, and are used to connect to both ends of an external heating pipeline. Specifically, heating inlet pipe 4a is equipped with a pressure relief valve 41 and is connected to an expansion tank 42 for containing and replenishing the expansion and contraction of circulating water in the circulation loop.

[0051] The domestic water inlet pipe 5a and the domestic water outlet pipe 5b are respectively connected to the two ends of the cold water channel of the heat exchanger 2. Specifically, a water supply pipe 51 is connected between the domestic water inlet pipe 5a and the heating water inlet pipe 4a, and a water supply valve 511 is installed on the water supply pipe 51 to control the opening and closing of the water supply pipe 51.

[0052] The delivery pump 6 is installed on the first heat exchange section 31 and can deliver water from the inlet end of the first heat exchange section 31 to the outlet end of the first heat exchange section 31.

[0053] The three-way valve 7 has an inlet end, a first outlet end, and a second outlet end. The inlet end of the three-way valve 7 is connected to the outlet end of the first heat exchange section 31, the first outlet end of the three-way valve 7 is connected to the inlet end of the second heat exchange section 32, and the second outlet end of the three-way valve 7 is connected to the heating outlet pipe 4b. The on / off state of the second heat exchange section 32 and the heating outlet pipe 4b can be controlled by adjusting the three-way valve 7.

[0054] By adjusting the three-way valve 7, the dual-purpose furnace can have at least two states:

[0055] In the first state, such as Figure 2 As shown, the second heat exchange section 32 is connected, and the heating outlet pipe 4b is disconnected, so that the heat exchange pipe 3 forms a separate circulation loop, that is, the internal circulation mentioned in the background art.

[0056] In the second state, such as Figure 3 As shown, the second heat exchange section 32 is disconnected, and the heating outlet pipe 4b is connected, so that the heating inlet pipe 4a, the first heat exchange section 31, the heating outlet pipe 4b and the external heating pipeline together form a circulation loop, that is, the external circulation mentioned in the background art.

[0057] In addition, the gas-fired boiler has a controller, and the flue gas temperature sensor 14, the proportional valve 1111 and the three-way valve 7 are all electrically connected to the controller so that the controller can receive the signal collected by the flue gas temperature sensor 14 and adjust the proportional valve 1111 and the three-way valve 7.

[0058] The working principle of this embodiment is as follows:

[0059] (1) In domestic hot water mode, the gas-fired boiler is switched to hot water mode via the three-way valve 7. Figure 2In the first state shown, the second heat exchange section 32 is connected and the heating outlet pipe 4b is disconnected, so that the heat exchange pipe 3 forms a separate circulation loop. Under the action of the delivery pump 6, the water in the first heat exchange section 31 of the heat exchange pipe 3 is heated by the combustion heat exchange device 1 and then enters the second heat exchange section 32. When the hot water in the second heat exchange section 32 passes through the heat exchanger 2, it exchanges heat with the cold water introduced by the domestic water inlet pipe 5a. After the cold water is heated into hot water, it is supplied to the user through the domestic water outlet pipe 5b. The water in the second heat exchange section 32 finally returns to the first heat exchange section 31 to replenish the heat, thereby realizing the continuous supply of domestic hot water.

[0060] (2) In heating mode, the gas-fired boiler is switched to the following mode via the three-way valve 7: Figure 3 In the second state shown, the second heat exchange section 32 is disconnected, and the heating outlet pipe 4b is connected, so that the heating inlet pipe 4a, the first heat exchange section 31, the heating outlet pipe 4b and the external heating pipeline together form a circulation loop. Under the action of the delivery pump 6, the water in the first heat exchange section 31 of the heat exchange pipe 3 is heated by the combustion heat exchange device 1 and discharged to the heating outlet pipe 4b. The hot water flows through each room to dissipate heat through the external heating pipeline, and finally returns to the first heat exchange section 31 through the heating inlet pipe 4a to replenish the heat, thereby achieving continuous heating for each room.

[0061] The present invention also provides a control method for the above-mentioned gas-fired dual-purpose boiler, comprising the following steps:

[0062] (1) The smoke temperature sensor 14 monitors the smoke temperature T inside the inner shell 11 and transmits the collected signal to the controller;

[0063] (2) The controller determines whether the smoke temperature T is greater than the set value Tmax or less than the set value Tmin:

[0064] ① If the flue gas temperature T is greater than the set value Tmax, it means that the flue gas temperature is too high, which means that the heat exchanger 12 is not exchanging heat in time. If this state is maintained, too much heat will be discharged directly outdoors with the exhaust gas through the exhaust pipe 113, resulting in waste of gas during use and difficulty in ensuring indoor comfort. At the same time, the excessively high flue gas temperature will cause varying degrees of damage and aging to the downstream fan 16, wind pressure sensor 17 and interface sealing gaskets, seriously affecting the service life of the whole machine.

[0065] Therefore, when the flue gas temperature is detected to be too high, the controller can quickly adjust the gas proportional valve 1111 in the system to reduce the gas supply, and the corresponding heat supply can be reduced rapidly until the flue gas temperature drops to a reasonable range.

[0066] ② If the flue gas temperature T is less than the set value Tmin, it means that the flue gas temperature is too low (usually occurs in heating mode, and low return water temperature and low combustion load are more likely to occur during the heating process, which easily produces condensate). Water vapor in the flue gas is very easy to condense. This acidic condensate will accumulate and drip onto the heat exchanger 12, burner 13 and other components below. This will cause corrosion to the contact parts. When the corrosion reaches a certain level, it will lead to safety issues or machine damage.

[0067] Therefore, when the flue gas temperature is detected to be too low, and the gas-fired boiler is currently in its first state (i.e., the gas-fired boiler is in such a state as...), Figure 2 In the domestic hot water mode shown, the controller can quickly adjust the gas proportional valve 1111 to increase the gas supply, thereby increasing the system's heat output, further increasing the flue gas temperature, and finally bringing the flue gas temperature to a reasonable range to avoid condensation.

[0068] When the flue gas temperature is detected to be too low, and the current gas-fired boiler is in the second state (i.e., the gas-fired boiler is in such a state as...) Figure 3 (As shown in the heating mode), the controller can control the three-way valve 7 to switch the gas-fired boiler to the first state, thus opening the internal circulation (e.g., Figure 2 At this time, the high-temperature effluent will mix with the low-temperature return water, raising the temperature of the influent water entering the heat exchanger 12. The heated influent water only needs to absorb a small amount of temperature from the flue gas, thereby increasing the flue gas temperature. At the same time, the controller can quickly adjust the gas proportional valve 1111 to increase the gas supply, thereby increasing the system's heat supply and further increasing the flue gas temperature, ultimately bringing the flue gas temperature to a reasonable range and preventing condensate from forming.

[0069] If the flue gas temperature T remains greater than the set value Tmax or less than the set value Tmin after a period of time, it can be determined that the heat exchanger 12 is blocked and has failed. The controller can immediately shut off the gas proportional valve 1111 and prompt for fault maintenance to avoid further damage.

Claims

1. A control method for a gas-fired dual-purpose boiler, wherein the gas-fired dual-purpose boiler includes... The combustion heat exchange device (1) includes an inner shell (11) and a heat exchanger (12) and a burner (13) disposed in the inner shell (11). The heat exchanger (12) has a heat exchange channel inside, and the burner (13) is used to supply heat to the heat exchanger (12). The heat exchanger (2) has a hot water channel and a cold water channel that exchange heat with each other. The heat exchange pipe (3) includes a first heat exchange section (31) and a second heat exchange section (32) connected in sequence. The first heat exchange section (31) passes through the heat exchange channel of the heat exchanger (12) in at least part, and the second heat exchange section (32) passes through the hot water channel of the heat exchanger (2) in at least part. The heating inlet pipe (4a) and heating outlet pipe (4b) are respectively connected to the two ends of the first heat exchange section (31) and are respectively used to connect to the two ends of an external heating pipeline; and The domestic water inlet pipe (5a) and the domestic water outlet pipe (5b) are respectively connected to the two ends of the cold water passage of the heat exchanger (2); Valves are provided on the second heat exchange section (32) and the heating outlet pipe (4b) to ensure that the dual-purpose boiler has at least two states: In the first state, the second heat exchange section (32) is connected, and the heating outlet pipe (4b) is disconnected; In the second state, the second heat exchange section (32) is disconnected, and the heating outlet pipe (4b) is connected. Its features are: The combustion heat exchange device (1) further includes a flue gas temperature sensor (14) for monitoring the flue gas temperature inside the inner shell (11). A gas pipeline (111) for supplying gas to the burner (13) is connected to the inner shell (11). A proportional valve (1111) for adjusting the amount of gas is installed on the gas pipeline (111). The gas-fired boiler has a controller, and the flue gas temperature sensor (14), the proportional valve (1111), and the valves on the second heat exchange section (32) and the heating water outlet pipe (4b) are all electrically connected to the controller. The control method includes the following steps: (1) The smoke temperature sensor (14) monitors the smoke temperature T inside the inner shell (11) and transmits the collected signal to the controller; (2) The controller determines whether the smoke temperature T is greater than the set value Tmax or less than the set value Tmin: If the flue gas temperature T is greater than the set value Tmax, the controller adjusts the proportional valve (1111) to reduce the gas supply. If the flue gas temperature T is less than the set value Tmin, and the gas-fired dual-purpose boiler is currently in the first state, the controller adjusts the proportional valve (1111) to increase the gas supply. If the flue gas temperature T is less than the set value Tmin, and the gas-fired boiler is currently in the second state, the controller controls the valves on the second heat exchange section (32) and the heating water outlet pipe (4b) to switch the gas-fired boiler to the first state and / or adjust the proportional valve (1111) to increase the gas supply. In step (2), if the flue gas temperature T is always greater than the set value Tmax or less than the set value Tmin after adjusting the proportional valve (1111) for a period of time, it can be determined that the heat exchanger (12) is blocked and fails. The controller immediately shuts off the gas proportional valve (1111) and prompts for fault maintenance.

2. The control method according to claim 1, characterized in that: The combustion heat exchange device (1) further includes an outer shell (15) disposed outside the inner shell (11). The inner wall of the outer shell (15) and the outer wall of the inner shell (11) have a sandwich (151). The inner shell (11) has an air supply hole (112) for connecting the inner cavity of the inner shell (11) and the sandwich (151). The inner shell (11) is connected to a flue gas exhaust pipe (113) for supplying flue gas. The outer shell (15) is connected to an air supply pipe (152) for supplying air. The inner shell (11) is equipped with a fan (16) for supplying air to the burner (13) and exhausting flue gas.

3. The control method according to claim 2, characterized in that: The gas supply pipe (152) is at least partially fitted around the outer periphery of the exhaust pipe (113).

4. The control method according to claim 2, characterized in that: The combustion heat exchange device (1) also includes a wind pressure sensor (17) for monitoring the wind pressure inside the flue gas duct (113).

5. The control method according to any one of claims 1 to 4, characterized in that: The second heat exchange section (32) and the heating outlet pipe (4b) share the same three-way valve (7). The three-way valve (7) has an inlet end, a first outlet end and a second outlet end. The inlet end of the three-way valve (7) is connected to the first heat exchange section (31), the first outlet end of the three-way valve (7) is connected to the second heat exchange section (32), and the second outlet end of the three-way valve (7) is connected to the heating outlet pipe (4b).

6. The control method according to any one of claims 1 to 4, characterized in that: The heat exchange pipe (3) or heating water inlet pipe (4a) is equipped with a pressure relief valve (41).

7. The control method according to any one of claims 1 to 4, characterized in that: A water supply pipe (51) is connected between the domestic water inlet pipe (5a) and the heating water inlet pipe (4a) or the heating water outlet pipe (4b), and a water supply valve (511) for controlling the opening and closing of the water supply pipe (51) is installed on the water supply pipe (51).

8. The control method according to any one of claims 1 to 4, characterized in that: An expansion tank (42) for containing and replenishing the expansion and contraction of circulating water in the circulation loop is connected to the heat exchange pipe (3) or heating water inlet pipe (4a).

9. The control method according to any one of claims 1 to 4, characterized in that: The gas-fired boiler also includes a transfer pump (6), which is installed on the first heat exchange section (31).

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