Backflow structure for grain moistening water feeder

Abstract

The utility model discloses a backflow structure for a grain moistening water feeder, which comprises a grain moistening vehicle, a water pump mounted on the grain moistening vehicle, a main pipe connected to the input end of the water pump, a water heating tank connected to the other side of the main pipe, a one-way valve mounted on the main pipe, an output main pipe connected to the output end of the water pump, and a flow meter connected to the output main pipe. The output end of the output main pipe is connected with a water outlet hose, the output end of the water outlet hose is connected with a grain moistening water feeding spray gun, and a backflow mechanism is installed between the grain moistening water feeding spray gun and the main pipe. After the grain moistening and water feeding spray gun is closed, water in the grain moistening and water feeding spray gun flows back into the water heating tank through the backflow mechanism, and flows out through the main pipe after being heated by the water heating tank, so that water in the main pipe, the output main pipe, the water outlet hose, the grain moistening and water feeding spray gun and the backflow mechanism can circularly flow after the grain moistening and water feeding spray gun is closed; and the water temperature in the pipeline is always kept above the required temperature, so that the action of discharging cold water is avoided, and the process requirements of the existing use are met.

Description

Technical Field

[0001] The utility model belongs to the technical field of wine making technology, and specifically relates to a reflux structure for a grain moistening water feeding device. Background Art

[0002] As liquor has a complex aroma with esters as the main body, it uses koji and yeast as saccharification and fermentation agents, and uses starch (sugar) raw materials. After cooking, saccharification, fermentation, distillation, aging and blending, liquor is divided into the following flavor types: sauce-flavored, light-flavored, strong-flavored, Laobaigan-flavored, rice-flavored, phoenix-flavored, mixed-flavored, Dong-flavored and other flavor types. Among them, the sauce-flavored liquor has a prominent sauce aroma, elegant and delicate, mellow body, long aftertaste, clear and transparent, and slightly yellowish color, which is widely praised by people. In the traditional In the grain moistening process of the winemaking process, hot water is used to soak the grain so that the grain can fully absorb water. However, there will be an interval between the addition of water to each pile of grain. During the interval of adding water, the water temperature in the pipeline of the grain moistening water doser will gradually drop below the required temperature. When adding water to moisten the grain again, the water in the pipeline that does not meet the temperature requirements must be discharged first. Only after the water temperature reaches the standard can water be added to the grain again to moisten the grain. The operation is relatively cumbersome and time-consuming, and cannot meet the process requirements. Therefore, a reflux structure for a grain moistening water doser is urgently needed to solve the above problems. Utility Model Content

[0003] In view of the problems raised by the above background technology, the purpose of the utility model is to provide a reflux structure for a grain moistening water dispenser.

[0004] In order to achieve the above technical purpose, the technical solution adopted by the utility model is as follows:

[0005] A reflux structure for a grain moistening water doser comprises a grain moistening vehicle, a water pump is installed in the grain moistening vehicle, the input end of the water pump is connected to a main pipe, the other side of the main pipe is connected to a water heating tank, a one-way valve is also installed on the main pipe, the output end of the water pump is connected to an output main pipe, the output main pipe is connected to a flow meter, the output end of the output main pipe is connected to a water outlet hose, the output end of the water outlet hose is connected to a grain moistening water doser, and a reflux mechanism is installed between the grain moistening water doser and the main pipe.

[0006] It is further defined that the reflux mechanism includes a first electric ball valve, which is installed on the outside of the grain moistening vehicle, the first electric ball valve is connected to a first transfer pipe, one side of the first transfer pipe is connected to a first reflux pipe, the other side of the first reflux pipe is connected to an output main pipe, the other side of the first transfer pipe is connected to a second reflux pipe, and the other side of the second reflux pipe is connected to a water heating tank. Such a structural design can achieve the effect of hot water circulation and prevent the water temperature from dropping.

[0007] It is further defined that the reflux mechanism also includes a second electric ball valve, which is installed in the grain moistening vehicle, and the second electric ball valve is connected to a second transfer pipe, one side of the second transfer pipe is connected to a third return pipe, and the other side of the third return pipe is connected to the output main pipe, and the other side of the second transfer pipe is connected to a fourth return pipe, and the other side of the fourth return pipe is connected to the main pipe, and the main pipe is installed with a first transfer return pipe on one side of the output end of the one-way valve, and a first transfer return control valve is installed on the first transfer return pipe, and the other side of the first transfer return pipe is arranged between the one-way valve and the water heating tank, and is connected to the main pipe. Such a structural design can achieve the effect of hot water circulation and prevent the water temperature from dropping.

[0008] It is further defined that the reflux mechanism also includes a third electric ball valve, which is installed in the grain moistening vehicle, and is connected to a third transfer pipe, one side of the third transfer pipe is connected to a fifth return pipe, and the other side of the fifth return pipe is connected to a three-way valve, one side of the three-way valve is connected to a grain moistening water spray gun, and the other side of the three-way valve is connected to a water outlet hose, and the other side of the third transfer pipe is connected to a sixth return pipe, and the other side of the sixth return pipe is connected to a second transfer return pipe, and a second transfer return control valve is installed on the second transfer return pipe, and the other side of the second transfer return pipe is arranged between the one-way valve and the water heating tank, and is connected to the main pipe. Such a structural design can achieve the effect of hot water circulation and prevent the water temperature from dropping.

[0009] Further defined, the reflux mechanism also includes a fourth electric ball valve, the fourth electric ball valve is installed in the grain moistening vehicle, the fourth electric ball valve is connected to a fourth transfer pipe, one side of the fourth transfer pipe is connected to a seventh return pipe, the other side of the seventh return pipe is connected to a first sealing plug-in, the first sealing plug-in is installed on the output main pipe, the first sealing plug-in is connected to a first flexible inner pipe, the first flexible inner pipe is arranged inside the output main pipe and the water outlet hose, the other side of the fourth transfer pipe is connected to an eighth return pipe, the other side of the eighth return pipe is connected to a second sealing plug-in, the second sealing plug-in is installed on the main pipe, the second sealing plug-in is connected to a second flexible inner pipe, the second flexible inner pipe is arranged in the main pipe, the other side of the second flexible inner pipe is connected to a third transfer return pipe, the third transfer return pipe is arranged on the outside of the main pipe, the third transfer return control valve is installed on the third transfer return pipe, the other side of the third transfer return pipe is connected to a third flexible inner pipe, the third flexible inner pipe is arranged in the main pipe, and is connected to the water heating tank. Such a structural design can achieve the effect of hot water circulation and prevent the water temperature from dropping.

[0010] The beneficial effects of the utility model are as follows: the utility model provides a reflux mechanism, and after the grain-moistening water spray gun is closed, the water in the grain-moistening water spray gun is refluxed into the water heating tank through the reflux mechanism, and after being heated by the water heating tank, the water flows out through the main pipe, so that after the grain-moistening water spray gun is closed, the water in the main pipe, the output main pipe, the water outlet hose, the grain-moistening water spray gun and the reflux mechanism can circulate, so that the water temperature in the pipeline is always maintained above the required temperature, thereby eliminating the action of discharging cold water, and the operation steps are simple, production will not be delayed, and the existing process requirements are met. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention can be further described by the non-limiting embodiments given in the accompanying drawings;

[0012] Figure 1 This is a structural schematic diagram of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0013] Figure 2 This is a schematic diagram of the first type of reflux mechanism structure of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0014] Figure 3 This is an enlarged structural diagram of point A of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0015] Figure 4 This is a schematic diagram of the second reflux mechanism structure of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0016] Figure 5 This is an enlarged structural diagram of point B of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0017] Figure 6 This is an enlarged structural diagram of the C position of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0018] Figure 7 This is a schematic diagram of the third type of reflux mechanism structure of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0019] Figure 8 This is an enlarged structural diagram of the D position of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0020] Fig. 9 This is an enlarged structural schematic diagram of position E of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0021] Fig.10 This is an enlarged structural diagram of the F position of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0022] Fig.11 This is a schematic diagram of a fourth type of reflux mechanism structure of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0023] Fig.12 This is an enlarged structural diagram of the G position of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0024] Fig.13 This is an enlarged structural schematic diagram of the H position of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0025] Fig.14 This is a schematic diagram of a flexible inner pipe connection structure of a reflux structure for a grain moistening water dispenser according to an embodiment of the utility model;

[0026] The main component symbols are described as follows:

[0027] Grain moistening vehicle 1, water pump 2, main pipe 3, water heating tank 4, one-way valve 5, output main pipe 6, flow meter 7, water outlet hose 8, grain moistening water spray gun 9, reflux mechanism 10, first electric ball valve 11, first transfer pipe 12, first reflux pipe 13, second reflux pipe 14, second electric ball valve 1101, second transfer pipe 15, third reflux pipe 16, fourth reflux pipe 17, first transfer reflux pipe 18, first transfer reflux control valve 19, third electric ball valve 110 2. The third transfer tube 20, the fifth return tube 21, the three-way valve 22, the sixth return tube 23, the second transfer return tube 24, the second transfer return control valve 25, the fourth electric ball valve 1103, the fourth transfer tube 26, the seventh return tube 27, the first sealing plug-in 28, the first flexible inner tube 29, the eighth return tube 30, the second sealing plug-in 31, the second flexible inner tube 32, the third transfer return tube 33, the third transfer return control valve 34, and the third flexible inner tube 35. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0029] Embodiment 1, as Figure 1 and Figure 3 As shown, a reflux structure for a grain moistening watering device is provided, a water pump 2 is installed in a grain moistening vehicle 1, the input end of the water pump 2 is connected to a main pipe 3, the other side of the main pipe 3 is connected to a water heating tank 4, a one-way valve 5 is also installed on the main pipe 3, the output end of the water pump 2 is connected to an output main pipe 6, the output main pipe 6 is connected to a flow meter 7, the output end of the output main pipe 6 is connected to a water outlet hose 8, the output end of the water outlet hose 8 is connected to a grain moistening watering spray gun 9, and a reflux mechanism 10 is installed between the grain moistening watering spray gun 9 and the main pipe 3.

[0030] In this embodiment, during normal use, the reflux mechanism 10 is in a closed state, the water pump 2 draws out the hot water in the water heating tank 4 and enters the main pipe 3 through the one-way valve 5, the main pipe 3 transports the hot water through the water pump 2 and enters the output main pipe 6, when the hot water flows in the output main pipe 6, the flow meter 7 performs metering to prevent the hot water from flowing out in excess, so as to achieve the effect of quantitative water injection, the hot water is output through the output main pipe 6 and enters the water outlet hose 8, and finally the water outlet hose 8 transports the hot water to the grain moistening water injection spray gun 9, and the grain is watered by the grain moistening water injection spray gun 9. After the water injection work is completed, the grain moistening water injection spray gun 9 is closed, at this time, in order to ensure the water temperature in the pipeline, the reflux mechanism 10 is controlled to start, so that the reflux mechanism 10 pumps the water in the pipeline back to the water heating tank 4, and after being heated by the water heating tank 4, it is pumped out by the water pump 2, so as to achieve a circulation effect and prevent the water temperature in the pipeline from dropping.

[0031] In normal use, the water pump 2 is used at normal power, and in heat preservation, the power of the water pump 2 is reduced to achieve hot water circulation.

[0032] Embodiment 2, as Figure 1 , Figure 2 and Figure 3 As shown, this embodiment adds the following structure on the basis of embodiment 1, the reflux mechanism 10 includes a first electric ball valve 11, the first electric ball valve 11 is installed on the outside of the grain moistening vehicle 1, the first electric ball valve 11 is connected to a first transfer pipe 12, one side of the first transfer pipe 12 is connected to a first return pipe 13, the other side of the first return pipe 13 is connected to the output main pipe 6, the other side of the first transfer pipe 12 is connected to a second return pipe 14, and the other side of the second return pipe 14 is connected to the water heating tank 4. Such a structural design can achieve the effect of hot water circulation and prevent the water temperature from dropping.

[0033] In this embodiment, when the reflux mechanism 10 is in use, the first electric ball valve 11 is opened to connect the first reflux pipe 13 with the output main pipe 6. The water in the output main pipe 6, the water outlet hose 8 and the grain moistening water spray gun 9 is pumped into the first transfer pipe 12 through the first reflux pipe 13, and outputted to the second reflux pipe 14 by the first transfer pipe 12. The second reflux pipe 14 then inputs the water into the water heating tank 4 for heating, and at the same time reduces the power of the water pump 2 so that the water pump 2 pumps the hot water out of the water heating tank 4 to achieve a circulation effect.

[0034] Embodiment 3, as Figure 4 , Figure 5 and Figure 6As shown, this embodiment adds the following structure on the basis of embodiment 1, the reflux mechanism 10 also includes a second electric ball valve 1101, the second electric ball valve 1101 is installed in the grain moistening vehicle 1, the second electric ball valve 1101 is connected to a second transfer pipe 15, one side of the second transfer pipe 15 is connected to a third reflux pipe 16, the other side of the third reflux pipe 16 is connected to the output main pipe 6, the other side of the second transfer pipe 15 is connected to a fourth reflux pipe 17, the other side of the fourth reflux pipe 17 is connected to the main pipe 3, the main pipe 3 is installed with a first transfer reflux pipe 18 on one side of the output end of the one-way valve 5, the first transfer reflux control valve 19 is installed on the first transfer reflux pipe 18, the other side of the first transfer reflux pipe 18 is arranged between the one-way valve 5 and the water heating tank 4, and is connected to the main pipe 3.

[0035] In this embodiment, when the reflux mechanism 10 is in use, by opening the second electric ball valve 1101 and the first transfer reflux control valve 19, the water in the output main pipe 6, the water outlet hose 8 and the grain moistening water spray gun 9 can flow back into the third reflux pipe 16, and is transported by the third reflux pipe 16 and passes through the second transfer pipe 15 and the fourth reflux pipe 17 in sequence and then enters the main pipe 3, and then is transported by the main pipe 3 to the first transfer reflux pipe 18, and enters the water heating tank 4 through the first transfer reflux control valve 19 for heating, and at the same time reduces the power of the water pump 2, so that the water pump 2 draws the hot water in the water heating tank 4 and inputs it into the main pipe 3 through the one-way valve 5, and is transported by the main pipe 3, thereby achieving the effect of hot water circulation.

[0036] Embodiment 4, as Figure 7 , Figure 8 , Fig. 9 and Fig.10 As shown, this embodiment adds the following structure on the basis of embodiment 1, the reflux mechanism 10 also includes a third electric ball valve 1102, the third electric ball valve 1102 is installed in the grain moistening vehicle 1, the third electric ball valve 1102 is connected to the third transfer tube 20, one side of the third transfer tube 20 is connected to the fifth return pipe 21, the other side of the fifth return pipe 21 is connected to the three-way valve 22, one side of the three-way valve 22 is connected to the grain moistening water spray gun 9, the other side of the three-way valve 22 is connected to the water outlet hose 8, the other side of the third transfer tube 20 is connected to the sixth return pipe 23, the other side of the sixth return pipe 23 is connected to the second transfer return pipe 24, the second transfer return pipe 24 is installed with a second transfer reflux control valve 25, the other side of the second transfer return pipe 24 is arranged between the one-way valve 5 and the water heating tank 4, and is connected to the main pipe 3.

[0037] In this embodiment, when the reflux mechanism 10 is in use, the third electric ball valve 1102 and the second transfer reflux control valve 25 are first opened, and the three-way valve 22 is closed at the same time, so that the grain moistening water spray gun 9 is connected with the fifth reflux pipe 21, and the water in the grain moistening water spray gun 9 flows into the fifth reflux pipe 21 through the three-way valve 22, and is transported by the fifth reflux pipe 21 to pass through the third transfer pipe 20, the sixth reflux pipe 23 and the second transfer reflux pipe 24 in sequence, and finally input into the water inlet heating tank 4 for heating, and then the three-way valve 22 is controlled again, so that the three-way valve 22 closes the grain moistening water spray gun 9, so that the water outlet hose 8 is connected with the fifth reflux pipe 21 through the three-way valve 22, and then the power of the water pump 2 is reduced, so that the water pump 2 draws the hot water in the water heating tank 4 and inputs it into the main pipe 3 through the one-way valve 5, and is transported by the main pipe 3, thereby achieving the effect of hot water circulation.

[0038] Embodiment 5, as Fig.11 , Fig.12 , Fig.13 and Fig.14 As shown, this embodiment adds the following structure on the basis of embodiment 1, the reflux mechanism 10 also includes a fourth electric ball valve 1103, the fourth electric ball valve 1103 is installed in the grain moistening vehicle 1, the fourth electric ball valve 1103 is connected to a fourth transfer pipe 26, one side of the fourth transfer pipe 26 is connected to a seventh reflux pipe 27, the other side of the seventh reflux pipe 27 is connected to a first sealing plug-in 28, the first sealing plug-in 28 is installed on the output main pipe 6, the first sealing plug-in 28 is connected to a first flexible inner pipe 29, the first flexible inner pipe 29 is arranged inside the output main pipe 6 and the water outlet hose 8, the other side of the fourth transfer pipe 26 is connected to There is an eighth return pipe 30, the other side of the eighth return pipe 30 is connected to a second sealing plug-in 31, the second sealing plug-in 31 is installed on the main pipe 3, the second sealing plug-in 31 is connected to a second flexible inner pipe 32, the second flexible inner pipe 32 is arranged in the main pipe 3, the other side of the second flexible inner pipe 32 is connected to a third transfer return pipe 33, the third transfer return pipe 33 is arranged on the outside of the main pipe 3, a third transfer return control valve 34 is installed on the third transfer return pipe 33, the other side of the third transfer return pipe 33 is connected to a third flexible inner pipe 35, the third flexible inner pipe 35 is arranged in the main pipe 3, and is connected to the water heating tank 4.

[0039] In this embodiment, when the reflux mechanism 10 is in use, the fourth electric ball valve 1103 and the third transfer reflux control valve 34 are first opened to allow the water in the grain moistening water spray gun 9, the water outlet hose 8 and the output main pipe 6 to flow into the first flexible inner pipe 29, and then pass through the first sealing plug-in 28, the seventh reflux pipe 27, the fourth transfer pipe 26, the eighth reflux pipe 30, the second sealing plug-in 31, the second flexible inner pipe 32, the third transfer reflux pipe 33, the third transfer reflux control valve 34 and the third flexible inner pipe 35 in sequence, and finally enter the water heating tank 4 for heating, while reducing the power of the water pump 2, so that the water pump 2 draws the hot water in the water heating tank 4 out and inputs it into the main pipe 3 through the one-way valve 5, and is transported by the main pipe 3, thereby achieving the effect of hot water circulation.

[0040] Among them, through the first sealing plug-in 28 and the second sealing plug-in 31, the sealing connection effect with the output main pipe 6 and the main pipe 3 can be guaranteed to prevent the water in the output main pipe 6 and the main pipe 3 from leaking, so that the first flexible inner pipe 29 can lead the water in the grain moistening water spray gun 9, the water outlet hose 8 and the output main pipe 6, and then input it into the second flexible inner pipe 32 in the main pipe 3, and transported by the second flexible inner pipe 32, thereby improving the effect of reflux use.

[0041] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the relevant technical field without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A reflux structure for a grain moistening water dispenser, characterized in that: The invention comprises a grain moistening vehicle (1), wherein a water pump (2) is installed in the grain moistening vehicle (1), the input end of the water pump (2) is connected to a main pipe (3), the other side of the main pipe (3) is connected to a water heating tank (4), a one-way valve (5) is also installed on the main pipe (3), the output end of the water pump (2) is connected to an output main pipe (6), the output main pipe (6) is connected to a flow meter (7), the output end of the output main pipe (6) is connected to a water outlet hose (8), the output end of the water outlet hose (8) is connected to a grain moistening water spray gun (9), and a reflux mechanism (10) is installed between the grain moistening water spray gun (9) and the main pipe (3).

2. A reflux structure for a grain moistening water dispenser according to claim 1, characterized in that: The reflux mechanism (10) comprises a first electric ball valve (11), the first electric ball valve (11) being installed on the outside of the grain moistening vehicle (1), the first electric ball valve (11) being connected to a first transfer tube (12), one side of the first transfer tube (12) being connected to a first reflux pipe (13), the other side of the first reflux pipe (13) being connected to an output main pipe (6), the other side of the first transfer tube (12) being connected to a second reflux pipe (14), the other side of the second reflux pipe (14) being connected to a water heating tank (4).

3. A reflux structure for a grain moistening water dispenser according to claim 2, characterized in that: The reflux mechanism (10) further comprises a second electric ball valve (1101), the second electric ball valve (1101) being installed in the grain moistening vehicle (1), the second electric ball valve (1101) being connected to a second transfer pipe (15), one side of the second transfer pipe (15) being connected to a third reflux pipe (16), the other side of the third reflux pipe (16) being connected to the output main pipe (6), the other side of the second transfer pipe (15) being connected to a fourth reflux pipe (17), the other side of the fourth reflux pipe (17) being connected to the main pipe (3), the main pipe (3) being installed with a first transfer reflux pipe (18) on one side of the output end of the one-way valve (5), the first transfer reflux pipe (18) being installed with a first transfer reflux control valve (19), the other side of the first transfer reflux pipe (18) being arranged between the one-way valve (5) and the water heating tank (4), and being communicated with the main pipe (3).

4. A reflux structure for a grain moistening water dispenser according to claim 3, characterized in that: The reflux mechanism (10) further comprises a third electric ball valve (1102), the third electric ball valve (1102) being installed in the grain moistening vehicle (1), the third electric ball valve (1102) being connected to a third transfer pipe (20), one side of the third transfer pipe (20) being connected to a fifth reflux pipe (21), the other side of the fifth reflux pipe (21) being connected to a three-way valve (22), one side of the three-way valve (22) being connected to a grain moistening water spray gun (9), The other side of the three-way valve (22) is connected to the water outlet hose (8), the other side of the third transfer pipe (20) is connected to the sixth return pipe (23), the other side of the sixth return pipe (23) is connected to the second transfer return pipe (24), the second transfer return pipe (24) is equipped with a second transfer return control valve (25), the other side of the second transfer return pipe (24) is arranged between the one-way valve (5) and the water heating tank (4), and is connected to the main pipe (3).

5. A reflux structure for a grain moistening water dispenser according to claim 4, characterized in that: The reflux mechanism (10) further comprises a fourth electric ball valve (1103), the fourth electric ball valve (1103) being installed in the grain moistening vehicle (1), the fourth electric ball valve (1103) being connected to a fourth transfer pipe (26), one side of the fourth transfer pipe (26) being connected to a seventh reflux pipe (27), the other side of the seventh reflux pipe (27) being connected to a first sealing plug-in (28), the first sealing plug-in (28) being installed on the output main pipe (6), the first sealing plug-in (28) being connected to a first flexible inner pipe (29), the first flexible inner pipe (29) being arranged inside the output main pipe (6) and the water outlet hose (8), the other side of the fourth transfer pipe (26) being connected to an eighth reflux pipe (30), the The other side of the eight return pipes (30) is connected to a second sealing plug-in (31), the second sealing plug-in (31) is installed on the main pipe (3), the second sealing plug-in (31) is connected to a second flexible inner pipe (32), the second flexible inner pipe (32) is arranged in the main pipe (3), the other side of the second flexible inner pipe (32) is connected to a third transfer return pipe (33), the third transfer return pipe (33) is arranged on the outside of the main pipe (3), a third transfer return control valve (34) is installed on the third transfer return pipe (33), the other side of the third transfer return pipe (33) is connected to a third flexible inner pipe (35), the third flexible inner pipe (35) is arranged in the main pipe (3) and is in communication with the water heating tank (4).

Images