Ring pipe straight-flow type natural gas boiler

Abstract

The utility model relates to the technical field of boiler equipment, and discloses an annular pipe straight-flow type natural gas boiler which comprises a machine shell, an inner container assembly, a natural gas burner, a water supply assembly, a water inlet assembly and an energy saver, the inner container assembly, the natural gas burner, the water supply assembly, the water inlet assembly and the energy saver are arranged in the machine shell side by side in a horizontal mode, and the natural gas burner is arranged on the inner container assembly. The water supply assembly is communicated with the inner container assembly and the energy saver, and the water inlet assembly is used for injecting softened water into the energy saver. Softened water in the energy saver is heated through smoke generated by combustion of the natural gas combustion machine, the heated softened water enters the inner container assembly and is further heated and vaporized through the natural gas combustion machine to form water vapor, and the whole process is energy-saving and environment-friendly. And the inner container assembly, the energy saver and the natural gas burner are all installed in the shell, the size and the occupied area of the whole machine are reduced, and transportation is more convenient.

Description

Technical Field

[0001] This utility model relates to the field of boiler equipment technology, specifically to a ring-tube direct-flow natural gas boiler. Background Technology

[0002] Existing boilers generally use fuel combustion, which has low thermal efficiency and produces a large amount of flue gas, failing to meet environmental protection requirements. In addition, they are large in size, occupy a large area, and are time-consuming and labor-intensive to transport and install. They also cannot automatically control the start and stop of heating, making it impossible to freely adjust the boiler load and posing significant safety hazards. Utility Model Content

[0003] In order to solve the problems existing in the prior art, the purpose of this utility model is to provide a ring-tube direct-flow natural gas boiler.

[0004] The present invention discloses a ring-tube direct-flow natural gas boiler, comprising a casing and an inner tank assembly, a natural gas burner, a water supply assembly, a water inlet assembly, and an economizer disposed within the casing. The inner tank assembly and the economizer are arranged horizontally side-by-side within the casing. The natural gas burner is mounted on the inner tank assembly. The water supply assembly connects the inner tank assembly and the economizer. The water inlet assembly is used to inject softened water into the economizer. The flue gas generated by the natural gas burner burning natural gas enters the economizer from the inner tank assembly to heat the softened water.

[0005] Preferably, the inner liner assembly includes:

[0006] The main body ring tube has a water inlet and a steam outlet arranged sequentially along the water flow direction.

[0007] A mosquito coil-shaped coil is disposed inside the main body ring tube, and its feed end is connected to the water inlet.

[0008] A double-layer spiral coil is provided inside the main body ring tube. The discharge end of the mosquito coil is connected to the inlet end of the double-layer spiral coil, and the discharge end of the double-layer spiral coil is connected to the steam outlet.

[0009] The main body smoke box is located at one end of the main body annular tube near the water inlet. One end of the main body smoke box is connected to the main body annular tube, and the other end is provided with a smoke outlet.

[0010] A natural gas burner interface is provided at the end of the main body ring tube away from the main body smoke box, and the natural gas burner interface is connected to the natural gas burner.

[0011] Preferably, the mosquito coil includes at least three layers of mosquito coil tubes, a connecting strip for fixing the mosquito coil tubes, a pressure plate disposed on the outer ring of the mosquito coil tubes, and a support ring disposed between the mosquito coil and the main body smoke box. The pressure plate connects adjacent mosquito coil tubes, and adjacent mosquito coil tubes are connected in series.

[0012] Preferably, the main body annular tube includes an annular tube shell, a water inlet / sewage pipe disposed at the water inlet, a steam outlet pipe disposed at the steam outlet, an inner liner support disposed at the bottom of the annular tube shell, and a furnace thermocouple disposed on the annular tube shell, wherein the furnace thermocouple is used to detect the temperature inside the annular tube shell.

[0013] Preferably, the water inlet / sewage discharge pipe includes a water inlet / sewage discharge pipe connected to the water inlet, a docking flange and a sewage discharge flange respectively disposed at both ends of the water inlet / sewage discharge pipe, and a water inlet pipe disposed on the water inlet / sewage discharge pipe. The docking flange is connected to the water inlet, the sewage discharge flange is connected to an external sewage discharge pipe, and the water inlet pipe is connected to the water supply assembly.

[0014] Preferably, the steam outlet pipeline includes a steam outlet pipe connected to the steam outlet, and a pressure gauge interface, a pressure controller interface, a pressure transmitter, a steam thermocouple interface, and a safety valve interface are sequentially arranged on the steam outlet pipe along the steam outflow direction. The pressure gauge interface, the pressure controller interface, the pressure transmitter, the steam thermocouple interface, and the safety valve interface are respectively used to connect the pressure gauge, the pressure controller, the pressure transmitter, the steam thermocouple, and the safety valve.

[0015] Preferably, the water supply assembly includes a water pump disposed inside the housing, a water supply pipe for connecting the inner tank assembly and the energy saver, and two check valves disposed on the water supply pipe near one end of the inner tank assembly.

[0016] Preferably, the water inlet assembly includes a water inlet pump disposed inside the housing, the water inlet end of the water inlet pump is externally connected to a soft water tank, and the water outlet end of the water inlet pump is connected to the energy saver through a water inlet pipe.

[0017] Preferably, the energy-saving device includes an energy-saving device housing, a flue gas inlet and a chimney disposed at both ends of the energy-saving device housing, an energy-saving device support and a condensate drain outlet disposed at the bottom of the energy-saving device housing, a finned tube assembly disposed inside the energy-saving device housing, an energy-saving device water inlet pipe and an energy-saving device water outlet pipe disposed outside the energy-saving device housing, a flue gas inlet temperature control thermocouple disposed on the flue gas inlet, and a chimney temperature control thermocouple disposed on the chimney. The flue gas inlet and the flue gas outlet are connected. The water inlet end of the finned tube assembly is connected to the energy-saving device water inlet pipe. The energy-saving device water inlet pipe is provided with an energy-saving device water inlet that is connected to the water inlet assembly. The water outlet end of the finned tube assembly is connected to the energy-saving device water outlet pipe. The energy-saving device water outlet pipe is provided with an energy-saving device water outlet that is connected to the water supply assembly.

[0018] Preferably, the finned tube assembly includes multiple finned tubes arranged side by side, with the two ends of the multiple finned tubes in the middle connected by elbows.

[0019] The advantages of the ring-tube direct-flow natural gas boiler described in this utility model are that the flue gas generated by the combustion of natural gas burner heats the softened water in the economizer. The heated softened water enters the inner tank assembly and is further heated and vaporized by the natural gas burner to form water vapor. The whole process is energy-saving and environmentally friendly. Moreover, the inner tank assembly, economizer and natural gas burner are all installed in the shell, which reduces the overall size and floor space, and makes transportation more convenient. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the ring-tube direct-flow natural gas boiler described in this utility model;

[0021] Figure 2 This is a side view of the annular tube direct-flow natural gas boiler described in this utility model;

[0022] Figure 3 This is a schematic diagram of the structure of the inner liner assembly described in this utility model;

[0023] Figure 4 This is the utility model described Figure 3 Sectional view of plane AA;

[0024] Figure 5 This is a schematic diagram of the winding process of the mosquito coil tubes SP1-SP2 described in this utility model;

[0025] Figure 6 This is a schematic diagram of the winding process of the mosquito coil tube SP3-SP5 described in this utility model;

[0026] Figure 7 This is an assembly diagram of the mosquito coil tubes SP1-SP2 described in this utility model;

[0027] Figure 8 This is an assembly diagram of the mosquito coil tube SP3-SP5 described in this utility model;

[0028] Figure 9 This is an assembly and forming diagram of the mosquito coil-shaped tube described in this utility model;

[0029] Figure 10 This is a schematic diagram of the structure of the water inlet / sewage outlet pipe described in this utility model;

[0030] Figure 11 This is a schematic diagram of the energy-saving device described in this utility model.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Housing; 101. Heat dissipation window; 102. Control panel; 103. Emergency stop switch;

[0033] 2 Inner liner assembly, 201 Water inlet, 202 Steam outlet, 203 Smoke outlet, 21 Body ring tube, 211 Ring tube shell, 212 Water inlet / sewage pipe, 2121 Water inlet / sewage pipe, 2122 Connecting flange, 2123 Sewage flange, 2124 Water inlet pipe, 213 Steam outlet pipe, 2131 Steam outlet pipe, 2132 Pressure gauge interface, 2133 Pressure controller interface, 2134 Pressure transmitter, 2135 Steam thermocouple interface, 2136 Safety valve interface, 214 Inner liner support, 215 Furnace thermocouple, 22 Mosquito coil, 221 Three-layer mosquito coil tube, 222 Connecting strip, 223 Pressure plate, 224 Support ring, 23 Double-layer spiral coil, 24 Body smoke box, 25 Natural gas burner interface;

[0034] 3. Natural gas burner;

[0035] 4. Water supply components; 41. Water supply pump; 42. Water supply pipe; 43. Check valve;

[0036] 5. Water inlet assembly; 51. Water inlet pump; 52. Water inlet pipeline;

[0037] 6. Energy saver, 61. Energy saver housing, 62. Flue gas inlet, 63. Chimney, 64. Energy saver bracket, 65. Finned tube assembly, 66. Energy saver water inlet pipe, 67. Energy saver water outlet pipe, 68. Flue gas inlet temperature control thermocouple, 69. Chimney temperature control thermocouple. Detailed Implementation

[0038] like Figure 1 and Figure 2As shown, the ring-tube once-through natural gas boiler disclosed in this embodiment includes a casing 1 and an inner tank assembly 2, a natural gas burner 3, a water supply assembly 4, a water inlet assembly 5, and an economizer 6 disposed within the casing 1. The inner tank assembly 2 and the economizer 6 are arranged horizontally side by side within the casing 1. The natural gas burner 3 is disposed on the inner tank assembly 2. The water supply assembly 4 connects the inner tank assembly 2 and the economizer 6. The water inlet assembly 5 is used to inject softened water into the economizer 6. The flue gas generated by the natural gas burner 3 from burning natural gas enters the economizer 6 from the inner tank assembly 2 to heat the softened water.

[0039] During operation, softened water is injected into the economizer 6 through the water inlet assembly 5. Flue gas from the natural gas burner 3 enters the economizer 6, heating the softened water. The heated water then flows into the inner tank assembly 2 through the water supply assembly 4. The natural gas burner 3 further heats the softened water in the inner tank assembly 2, causing it to vaporize and form steam. Throughout this process, the flue gas produced by the natural gas burner 3 is more environmentally friendly than directly burning fuel. The flue gas provides initial heating to the softened water in the economizer 6, ensuring the water entering the inner tank assembly 2 reaches a certain temperature, thus achieving heat recycling. All components are housed within the casing 1, resulting in high integration, a compact structure, reduced overall size and footprint, and easier transportation.

[0040] In this embodiment, multiple heat dissipation windows 101 are provided on the outer side of the housing 1 to dissipate heat from the various structures inside the housing 1. The housing 1 is also equipped with a control panel 102 and an emergency stop switch 103. The control panel 102 can control and monitor the working status of each structure in real time, and the emergency stop switch 103 can stop the operation of the equipment in time in case of an emergency to ensure the safety of equipment operation.

[0041] Please refer to Figures 3-9 The inner liner assembly 2 includes a main body ring tube 21, a mosquito coil-shaped coil 22, a double-layer spiral coil 23, a main body smoke box 24, and a natural gas burner interface 25. The main body ring tube 21 is provided with an inlet 201 and a steam outlet 202 in sequence along the water flow direction. The mosquito coil 22 is located inside the main body ring tube 21, and its feed end is connected to the inlet 201. The double-layer spiral coil 23 is located inside the main body ring tube 21, and the discharge end of the mosquito coil 22 is connected to the feed end of the double-layer spiral coil 23. The discharge end of the double-layer spiral coil 23 is connected to the steam outlet 202. The main body smoke box 24 is located at one end of the main body ring tube 21 near the inlet 201. One end of the main body smoke box 24 is connected to the main body ring tube 21, and the other end is provided with a smoke outlet 203. The natural gas burner interface 25 is located at the end of the main body ring tube 21 away from the main body smoke box 24, and the natural gas burner interface 25 is connected to the natural gas burner 3.

[0042] In this embodiment, the natural gas burner interface 25 is connected to the natural gas burner 3. Natural gas is a clean energy source, and its combustion products have less environmental pollution, making it more environmentally friendly than fuel combustion. Moreover, natural gas has a higher thermal efficiency than fuel combustion. The coil and spiral configuration of the mosquito coil 22 and the double-layer spiral coil 23 can reduce the volume of the steam generator while ensuring heat exchange efficiency, thereby reducing the floor space required. The heat generated by the natural gas burner 3 from burning natural gas enters the main body ring tube 21 through the natural gas burner interface 25 and exchanges heat with the mosquito coil 22 and the double-layer spiral coil 23. The flue gas generated by the combustion of natural gas by the natural gas burner 3 finally flows out from the flue gas outlet 203.

[0043] In this embodiment, the mosquito coil 22 includes at least three layers of mosquito coil tubes 221, connecting strips 222 for fixing the mosquito coil tubes 221, pressure plates 223 disposed on the outer ring of the mosquito coil tubes 221, and support rings 224 disposed between the mosquito coil 22 and the main body smoke box 24. The pressure plates 223 connect adjacent mosquito coil tubes 221, and adjacent mosquito coil tubes 221 are connected in series. Preferably, the mosquito coil tubes 221 are provided with five layers. The diameter of the three layers of mosquito coil tubes 221 closest to the water inlet 201 is smaller than the diameter of the other two layers of mosquito coil tubes 221, and the diameter of the other two layers of mosquito coil tubes 221 is the same as the diameter of the double-layer spiral coil 23. Specifically, the five layers of mosquito coil tubes 221 are connected in series, numbered SP1-SP5. SP1 and SP2 have a diameter of 25cm, while SP3-SP5 have a diameter of 18cm. The double-layer spiral disc 23 is formed by winding two layers of 25cm diameter tubes counterclockwise (starting from the bottom in the top view) 15 times. When water flows from the smaller diameter mosquito coil tube 221 into the larger diameter mosquito coil tube 221, the flow rate decreases, thus increasing the heat exchange time and ensuring steam efficiency. The mosquito coil tubes 221 are filled with refractory clay for insulation, reducing heat loss.

[0044] Preferably, the main body annular tube 21 includes an annular tube shell 211, a water inlet / sewage outlet pipe 212 disposed at the water inlet 201, a steam outlet pipe 213 disposed at the steam outlet 202, an inner liner support 214 disposed at the bottom of the annular tube shell 211, and a furnace thermocouple 215 disposed on the annular tube shell 211. The furnace thermocouple 215 is used to detect the temperature inside the annular tube shell 211.

[0045] Specifically, the water inlet / sewage discharge pipe 212 includes a water inlet / sewage discharge pipe 2121 connected to the water inlet 201, a docking flange 2122 and a sewage discharge flange 2123 respectively installed at both ends of the water inlet / sewage discharge pipe 2121, and a water inlet pipe 2124 installed on the water inlet / sewage discharge pipe 2121. The docking flange 2122 is connected to the water inlet 201, the sewage discharge flange 2123 is connected to the external sewage discharge pipe, and the water inlet pipe 2124 is connected to the water supply assembly 4.

[0046] Preferably, the steam outlet pipe 213 includes a steam outlet pipe 2131 connected to the steam outlet 202, and a pressure gauge interface 2132, a pressure controller interface 2133, a pressure transmitter 2134, a steam thermocouple interface 2135, and a safety valve interface 2136 are sequentially arranged on the steam outlet pipe 2131 along the steam outflow direction. The pressure gauge interface 2132, the pressure controller interface 2133, the pressure transmitter 2134, the steam thermocouple interface 2135, and the safety valve interface 2136 are respectively used to connect the pressure gauge, the pressure controller, the pressure transmitter, the steam thermocouple, and the safety valve.

[0047] The pressure gauge monitors the steam pressure in real time, and the steam generator load is controlled using a safety valve, pressure controller, and pressure transmitter. The pressure controller and transmitter monitor the steam pressure intensity within the coils, enabling fully automatic load adjustment of the steam generator. When steam overpressure occurs due to external steam supply failure or other abnormal conditions, the pressure controller immediately cuts off power to stop the steam generator. Simultaneously, the safety valve opens to release steam and relieve pressure. The steam temperature is monitored in real time via a steam thermocouple. If the detected steam temperature is too high, the abnormal signal from the steam thermocouple immediately cuts off power to stop the boiler and simultaneously issues an audible and visual alarm. The furnace thermocouple 215 monitors the furnace temperature of the main ring tube 21 in real time. When the furnace temperature is too high, the abnormal signal output by the furnace thermocouple 215 will immediately cut off the power and shut down the furnace. The temperature control thermocouple 68 at the flue gas inlet can monitor the temperature of the flue gas inlet 62 in real time. When the temperature of the flue gas inlet 62 is detected to be too high, the power will immediately cut off the furnace and shut down the furnace. The temperature control thermocouple 69 at the chimney can monitor the temperature of the chimney 63 in real time and output and display the real-time flue gas temperature signal. When the temperature of the chimney 63 is too high, the power will immediately cut off the furnace and shut down the furnace. The furnace has a high level of automation and complete safety protection devices, making it easy to operate, safe and reliable in operation, and able to achieve fully automatic water supply and operation.

[0048] Preferably, the water supply assembly 4 includes a water pump 41 disposed inside the housing 1, a water supply pipe 42 for connecting the inner tank assembly 2 and the energy saver 6, and two check valves 43 disposed on the water supply pipe 42 near one end of the inner tank assembly 2. These check valves prevent backflow and also prevent wastewater from entering the water supply assembly 4 through the inlet pipe 2124 during drainage. The water inlet assembly 5 includes a water pump 51 disposed inside the housing 1. The inlet end of the water pump 51 is connected to a soft water tank, and the outlet end of the water pump 51 is connected to the energy saver 6 through the inlet pipe 52. In operation, the water pump 51 pumps softened water from the soft water tank into the energy saver 6 through the inlet pipe 52, and the water pump 41 pumps softened water heated by the energy saver 6 into the inner tank assembly 2 through the water supply pipe 42.

[0049] Preferably, the energy saver 6 includes an energy saver housing 61, a flue gas inlet 62 and a chimney 63 disposed at both ends of the energy saver housing 61, an energy saver support 64 and a condensate drain outlet disposed at the bottom of the energy saver housing 61, a finned tube assembly 65 disposed inside the energy saver housing 61, an energy saver water inlet pipe 66 and an energy saver water outlet pipe 67 disposed outside the energy saver housing 61, a flue gas inlet temperature control thermocouple 68 disposed on the flue gas inlet 62, and a chimney temperature control thermocouple 69 disposed on the chimney 63. The flue gas inlet 62 is connected to the flue gas outlet 203. The water inlet end of the finned tube assembly 65 is connected to the energy saver water inlet pipe 66. The energy saver water inlet pipe 66 is provided with an energy saver water inlet that is connected to the water inlet assembly 5. The water outlet end of the finned tube assembly 65 is connected to the energy saver water outlet pipe 67. The energy saver water outlet pipe 67 is provided with an energy saver water outlet that is connected to the water supply assembly 4. The finned tube assembly 65 includes multiple finned tubes arranged side by side, with the two ends of the multiple finned tubes in the middle connected by elbows. Softened water enters the finned tube assembly 65 through the energy-saving device inlet pipe 66, then enters the energy-saving device outlet pipe 67, and is finally pumped into the inner tank assembly 2 by the water supply pump 41. Flue gas flows out from the chimney 63 after passing through the energy-saving device housing 61.

[0050] In summary, this embodiment heats the softened water in the economizer 6 with the flue gas generated by the combustion of the natural gas burner 3. The heated softened water enters the inner tank assembly 2 and is further heated and vaporized by the natural gas burner 3 to form water vapor. The whole process is energy-saving and environmentally friendly. Moreover, by installing the inner tank assembly 2, the economizer 6 and the natural gas burner 3 all inside the shell 1, the overall size and floor space of the machine are reduced, making transportation more convenient.

[0051] In the description of this utility model, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this utility model.

[0052] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this utility model.

Claims

1. A once-through natural gas-fired boiler of the drumless type, characterized in that, The application relates to a natural gas boiler, which comprises a casing (1), an inner container assembly (2), a natural gas burner (3), a water supply assembly (4), a water inlet assembly (5) and an economizer (6) arranged in the casing (1), the inner container assembly (2) and the economizer (6) are horizontally arranged side by side in the casing (1), the natural gas burner (3) is arranged on the inner container assembly (2), the water supply assembly (4) is connected with the inner container assembly (2) and the economizer (6), the water inlet assembly (5) is used for injecting softened water into the economizer (6), and the flue gas generated by burning natural gas in the natural gas burner (3) enters the economizer (6) from the inner container assembly (2) to heat the softened water.

2. The once-through natural gas-fired drum boiler of claim 1, wherein, The inner container assembly (2) comprises: a body annular tube (21), which is sequentially provided with a water inlet (201) and a steam outlet (202) along the water flow direction; a mosquito-repellent incense-shaped coil (22), which is arranged in the body annular tube (21) and is communicated with the water inlet (201); a double-layer spiral coil (23), which is arranged in the body annular tube (21) and is communicated with the outlet end of the mosquito-repellent incense-shaped coil (22) and the inlet end of the double-layer spiral coil (23), and the outlet end of the double-layer spiral coil (23) is communicated with the steam outlet (202); a body smoke box (24), which is arranged at one end of the body annular tube (21) close to the water inlet (201), one end of the body smoke box (24) is communicated with the body annular tube (21), and the other end is provided with a smoke outlet (203); a natural gas burner interface (25), which is arranged at one end of the body annular tube (21) away from the body smoke box (24) and is connected with the natural gas burner (3).

3. The once-through natural gas-fired drum boiler of claim 2, wherein, The mosquito-repellent incense-shaped coil (22) comprises at least three mosquito-repellent incense pipes (221), connecting plate strips (222) for fixing the mosquito-repellent incense pipes (221), pressing plates (223) arranged at the outer circles of the mosquito-repellent incense pipes (221) and support rings (224) arranged between the mosquito-repellent incense-shaped coil (22) and the body smoke box (24), the pressing plates (223) are connected with adjacent mosquito-repellent incense pipes (221), and the adjacent mosquito-repellent incense pipes (221) are connected in series.

4. The once-through natural gas-fired drum boiler of claim 2, wherein, The body annular tube (21) comprises an annular tube shell (211), a water inlet / drainage pipeline (212) arranged at the water inlet (201), a steam outlet pipeline (213) arranged at the steam outlet (202), an inner container support (214) arranged at the bottom of the annular tube shell (211) and a hearth thermocouple (215) arranged on the annular tube shell (211), and the hearth thermocouple (215) is used for detecting the temperature in the annular tube shell (211).

5. The once-through natural gas-fired drum boiler of claim 4, wherein, The water inlet / bleed pipe (212) comprises a water inlet / bleed pipe (2121) communicated with the water inlet (201), a butt flange (2122) and a bleed flange (2123) respectively arranged at both ends of the water inlet / bleed pipe (2121), and a water inlet pipe (2124) arranged on the water inlet / bleed pipe (2121), the butt flange (2122) butts the water inlet (201), the bleed flange (2123) butts an external bleed pipe, and the water inlet pipe (2124) communicates the water supply assembly (4).

6. The once-through natural gas-fired drum boiler of claim 5, wherein, The steam outlet pipe (213) comprises a steam outlet pipe (2131) communicated with the steam outlet (202), a pressure gauge interface (2132), a pressure controller interface (2133), a pressure transmitter (2134), a steam thermocouple interface (2135), and a safety valve interface (2136) arranged on the steam outlet pipe (2131) in sequence along the steam outflow direction, and the pressure gauge interface (2132), the pressure controller interface (2133), the pressure transmitter (2134), the steam thermocouple interface (2135), and the safety valve interface (2136) are respectively used for connecting a pressure gauge, a pressure controller, a pressure transmitter, a steam thermocouple, and a safety valve.

7. The once-through natural gas-fired drum boiler of claim 2, wherein, The water supply assembly (4) comprises a water supply pump (41) arranged inside the machine shell (1), a water supply pipe (42) for communicating the inner container assembly (2) and the energy saver (6), and two check valves (43) arranged on the water supply pipe (42) near one end of the inner container assembly (2).

8. The once-through natural gas-fired drum boiler of claim 2, wherein, The water inlet assembly (5) comprises a water inlet pump (51) arranged inside the machine shell (1), the water inlet end of the water inlet pump (51) is connected with a soft water tank, and the water outlet end of the water inlet pump (51) is communicated with the energy saver (6) through a water inlet pipeline (52).

9. The once-through natural gas-fired drum boiler of claim 2, wherein, The energy saver (6) comprises an energy saver shell (61), an inlet flue (62) and a chimney (63) arranged at both ends of the energy saver shell (61), an energy saver support (64) and a condensate water bleed port arranged at the bottom of the energy saver shell (61), a finned tube group (65) arranged in the energy saver shell (61), an energy saver water inlet pipe (66) and an energy saver water outlet pipe (67) arranged on the outer side of the energy saver shell (61), an inlet flue temperature control thermocouple (68) arranged on the inlet flue (62), and a chimney temperature control thermocouple (69) arranged on the chimney (63), the inlet flue (62) is communicated with the smoke outlet (203), the water inlet end of the finned tube group (65) is communicated with the energy saver water inlet pipe (66), the energy saver water inlet pipe (66) is provided with an energy saver water inlet communicated with the water inlet assembly (5), the water outlet end of the finned tube group (65) is communicated with the energy saver water outlet pipe (67), and the energy saver water outlet pipe (67) is provided with an energy saver water outlet communicated with the water supply assembly (4).

10. The once-through natural gas-fired drum boiler of claim 9, wherein, The finned tube group (65) includes a plurality of finned tubes arranged side by side, and both ends of the middle finned tubes are communicated by elbows. The finned tube group (65) includes a plurality of finned tubes arranged side by side, and both ends of the middle finned tubes are communicated by elbows.

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