A gas water heater and a water flow sensor therefor

Abstract

The utility model provides a kind of gas water heater and water flow sensor for it.The water flow sensor includes shell, rotor and lower rotor base being arranged in the shell, the lower rotor base is fixedly connected with the shell, the first end of the rotor is pivotally connected with the lower rotor base, the first end of the rotor is provided with first limiting structure, the second limiting structure is provided on the lower rotor base;The rotor can move along the axial direction of the shell, when the second limiting structure and the first limiting structure stop, the rotor stops rotating.The utility model sets first limiting structure on the first end of the rotor, sets second limiting structure on the lower rotor base, so that the rotor stops rotating quickly, improves the response speed of water flow sensor, shortens delay time, avoids the temperature rise caused by water flow sensor response slow due to water stop, improves the thermal efficiency of gas water heater.

Description

Technical Field

[0001] This utility model relates to the field of gas water heater technology, and in particular to a gas water heater and a water flow sensor used therein. Background Technology

[0002] A gas water heater's water flow sensor detects water flow by rotating a rotor. Different rotor speeds reflect varying water flow rates in the pipes, allowing the heater to adjust combustion intensity accordingly to produce hot water that meets the user's needs. When the gas water heater stops working, water flow ceases, and the water flow sensor's rotor gradually stops rotating. Once the rotor is stationary, the Hall effect sensor no longer receives the rotation signal, at which point gas supply stops, and combustion ceases.

[0003] During a shutdown, when the water supply is momentarily interrupted, the water flow sensor rotor continues to rotate due to inertia. The Hall effect sensor outside the flow sensor still receives this rotational information, and the combustion chamber continues to heat the stagnant water in the pipes, resulting in a stream of very hot water within the combustion chamber. When the user tries to use the water again, a sudden flow of very hot water will occur, causing significant temperature fluctuations and negatively impacting the user experience.

[0004] The most effective way to address the temperature rise during water outages is to extend a bypass pipe from the main heat exchanger's inlet pipe, directly connecting it to the outlet pipe. With the bypass pipe at the inlet end, when the user's water supply is interrupted, the low-temperature water from the inlet pipe enters the outlet pipe and mixes with the high-temperature water inside the heat exchanger tubes, thus reducing the temperature rise in the outlet pipe. By designing the bypass pipe's diameter and structure, the flow rate of low-temperature water entering the outlet pipe can be controlled, thereby reducing temperature fluctuations during re-starting the water supply.

[0005] However, while controlling the amount of low-temperature water entering the outlet pipe by designing the bypass pipe diameter can mitigate the temperature rise during water outages, the combustion intensity is adjusted based on the inlet water flow. Therefore, when the bypass pipe diverts a portion of the inlet water flow, the actual water flow in the heat exchange tubes that can absorb heat decreases, leading to a reduction in the thermal efficiency of the gas water heater. Since thermal efficiency is a crucial performance indicator for gas water heaters, accelerating the response of the water flow sensor to water inflow cessation is an effective way to address this problem.

[0006] In existing related technologies, a brake ring is set up, and the friction between the brake ring and the rotor is used to overcome the rotor's inertia and stop its rotation. However, overcoming the rotor's inertia with friction still has a certain delay, resulting in less than ideal results.

[0007] In view of the above, this utility model is hereby proposed. Utility Model Content

[0008] The technical problem to be solved by this utility model is to overcome at least some of the shortcomings of the prior art and provide a water flow sensor. By setting a first limiting structure at the first end of the rotor and a second limiting structure on the lower rotor seat, the rotor can move along the axial direction of the outer shell. The second limiting structure abuts against the first limiting structure, so that the rotor stops rotating quickly, thereby improving the response speed of the water flow sensor, shortening the delay time, avoiding water outage and temperature rise caused by slow response of the water flow sensor, and improving the thermal efficiency of the gas water heater.

[0009] To solve the above-mentioned technical problems, the first aspect of this utility model is to provide a water flow sensor, including a housing, a rotor disposed in the housing and a lower rotor seat, wherein the lower rotor seat is fixedly connected to the housing, and the first end of the rotor is pivotally connected to the lower rotor seat;

[0010] The first end of the rotor is provided with a first limiting structure, and the lower rotor seat and / or the inner wall of the outer shell are provided with a second limiting structure;

[0011] The rotor can move axially along the outer casing, and when the second limiting structure abuts against the first limiting structure, the rotor stops rotating.

[0012] In some embodiments, the rotor includes a shaft and a plurality of blades disposed on the shaft, wherein a first pivot protrudes from a first end of the shaft;

[0013] The lower rotor seat includes a lower seat body, which is fixedly connected to the outer shell and pivotally connected to the first end of the rotating shaft;

[0014] The first limiting structure and the second limiting structure are respectively disposed on the opposite end faces of the rotating shaft and the lower seat.

[0015] In some embodiments, the first limiting structure is at least one first limiting protrusion provided on the end face of the rotating shaft and extending radially, and the second limiting structure is at least one second limiting protrusion provided on the end face of the lower seat and extending radially.

[0016] The sidewalls of the first limiting protrusion and the sidewalls of the second limiting protrusion stop the rotor from rotating.

[0017] In some embodiments, a swirl vane is provided on the lower body, and the swirl vane rotates in a first direction along the circumference.

[0018] Wherein, the surface of the first limiting protrusion smoothly transitions downward from the top of its sidewall to its root in a direction opposite to the first direction, and the surface of the second limiting protrusion smoothly transitions downward from the top of its sidewall to its root in the first direction.

[0019] In some embodiments, the lower seat, the swirl vane, and the outer shell are integrally formed.

[0020] In some embodiments, the rotor includes a shaft and a plurality of blades disposed on the shaft;

[0021] The lower rotor seat includes a lower seat body, which is fixedly connected to the outer shell;

[0022] One of the lower seat body and the first end of the rotating shaft is provided with a pivot shaft, and the other of the lower seat body and the first end of the rotating shaft is provided with a pivot hole, and the pivot shaft is pivotally connected to the pivot hole;

[0023] The first limiting structure and the second limiting structure are respectively disposed on the opposite end faces of the pivot shaft and the pivot hole.

[0024] In some embodiments, the first limiting structure and the second limiting structure are respectively a stop rib and a stop block disposed on the end faces opposite to the pivot shaft and the pivot hole.

[0025] In some embodiments, the rotor includes a shaft and a plurality of blades disposed on the shaft;

[0026] The lower rotor seat includes a lower seat body, which is fixedly connected to the outer shell and pivotally connected to the first end of the rotating shaft;

[0027] Any one of the plurality of blades constitutes the first limiting structure, and the second limiting structure is a stop portion disposed on the inner wall of the outer casing.

[0028] In some embodiments, the lower seat body is provided with a weight-reducing hole.

[0029] In some embodiments, the water flow sensor further includes an upper rotor seat fixedly connected to the housing, the upper rotor seat being pivotally connected to a second end of the shaft.

[0030] In some embodiments, the upper rotor seat includes an upper seat body and an annular seat, and at least two ribs are provided between the upper seat body and the annular seat;

[0031] The upper seat is pivotally connected to the second end of the rotating shaft, and the ring seat is fastened to the outer shell.

[0032] In some embodiments, the upper seat is provided with upper seat weight reduction holes.

[0033] A second aspect of this utility model also provides a gas water heater, including the water flow sensor described above.

[0034] By adopting the above technical solution, this utility model has the following beneficial effects compared with the prior art.

[0035] The water flow sensor for gas water heaters provided by this utility model has a first limiting structure at the first end of the rotor and a second limiting structure on the lower rotor seat. The rotor can move along the axial direction of the outer shell. When the second limiting structure abuts against the first limiting structure, the rotor stops rotating quickly, which improves the response speed of the water flow sensor, shortens the delay time, avoids water outage and temperature rise caused by slow response of the water flow sensor, and improves the thermal efficiency of the gas water heater. Attached Figure Description

[0036] The accompanying drawings, as part of this utility model, are used to provide a further understanding of the present utility model. The illustrative embodiments and descriptions of the present utility model are used to explain the present utility model, but do not constitute an undue limitation of the present utility model. Obviously, the drawings described below are merely some embodiments; those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0037] Figure 1 This is a schematic diagram of the structure of a water flow sensor for a gas water heater according to the present invention;

[0038] Figure 2 This is a structural schematic diagram from another perspective of a water flow sensor for a gas water heater provided by this utility model;

[0039] Figure 3 According to the first method provided by this utility model Figure 1 The main view of the structure;

[0040] Figure 4 yes Figure 3 Sectional view along line AA in the middle;

[0041] Figure 5A and Figure 5B These are structural schematic diagrams of the rotor from different perspectives according to Method 1 provided by this utility model;

[0042] Figure 6 This is a structural schematic diagram of the upper rotor seat provided by this utility model;

[0043] Figure 7This is a structural schematic diagram of the outer shell and lower rotor seat according to Embodiment 1 provided by this utility model;

[0044] Figure 8 yes Figure 7 Another view of the structure;

[0045] Figure 9 yes Figure 8 BB-direction sectional view in the middle;

[0046] Figure 10 According to the second embodiment provided by this utility model Figure 1 Right view of the middle structure;

[0047] Figure 11 yes Figure 10 CC-direction section view;

[0048] Figure 12 yes Figure 11 A magnified view of point I in the image;

[0049] Figure 13 This is a schematic diagram of the rotor structure according to Embodiment 2 provided by this utility model;

[0050] Figure 14 It is according to the third method provided by this utility model Figure 1 Left view of the middle structure;

[0051] Figure 15 yes Figure 14 DD section view in the middle;

[0052] Figure 16 yes Figure 15 A magnified view of section II in the image.

[0053] In the diagram: 100, water flow sensor;

[0054] 110. Outer casing; 111. Inlet; 112. Outlet; 113. Annular boss; 114. Mounting groove; 115. Stop part;

[0055] 120. Rotor; 121. Shaft; 122. Blade; 123. First pivot shaft; 124. Second pivot shaft; 125. First limiting protrusion; 126. Stop rib 126;

[0056] 130. Upper rotor seat; 131. Upper seat body; 132. Ring seat; 133. Rib plate; 134. Water passage hole; 135. Mounting protrusion; 136. Weight reduction hole of upper seat body; 137. Second shaft hole;

[0057] 140. Lower rotor seat; 141. Lower seat body; 142. Swirl vane; 143. First shaft hole; 144. Lower seat body weight reduction hole; 145. Second limiting protrusion; 146. Stop block 146.

[0058] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the present invention in any way, but rather to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0060] In the description of this utility model, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and 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 limitations on this utility model.

[0061] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0062] As described in the background section, existing technologies that utilize the friction between the brake ring and the rotor to overcome the rotor's inertia have a certain time delay, resulting in an unsatisfactory effect on accelerating the water flow sensor's response to the cessation of water inflow. Therefore, this invention provides a water flow sensor for gas water heaters. By setting a first limiting structure at the first end of the rotor and a second limiting structure on the lower rotor seat and / or the inner wall of the outer casing, the rotor can move axially along the outer casing. The second limiting structure abuts against the first limiting structure, causing the rotor to stop rotating quickly. This improves the response speed of the water flow sensor, shortens the delay time, avoids temperature rise due to water outage caused by slow response of the water flow sensor, and improves the thermal efficiency of the gas water heater.

[0063] The preferred technical solutions of the gas water heater and the water flow sensor used therein provided by this utility model are described below with reference to the accompanying drawings.

[0064] like Figures 1 to 16 As shown, a water flow sensor 100 for a gas water heater includes a housing 110, a rotor 120, an upper rotor seat 130, and a lower rotor seat 140. The housing 110 is a hollow cylindrical structure with a through inlet 111 and an outlet 112. The upper rotor seat 130 is located at the outlet 112, and the lower rotor seat 140 is located at the inlet 111. Both the upper rotor seat 130 and the lower rotor seat 140 are fixedly connected to the housing 110. The first and second ends of the rotor 120 are pivotally connected to the lower rotor seat 140 and the upper rotor seat 130, respectively. The rotor 120 is axially movable along the housing 110. The first end of the rotor 120 is provided with a first limiting structure, and the lower rotor seat 140 and / or the inner wall of the housing 110 are provided with a second limiting structure.

[0065] It is understood that the rotor 120 of this invention is a magnetic rotor, and the water flow sensor 100 also includes a Hall effect sensor disposed outside the housing 110. After the water flows into the housing 110 through the inlet 111, it pushes the rotor 120 to move upward along the axial direction of the housing 110. The first limiting structure disengages from the limiting effect of the second limiting structure. When the magnetic rotor rotates under the action of the water flow, it generates a rotating magnetic field with different magnetic poles, cutting magnetic induction lines. After being sensed by the Hall effect sensor, it outputs high and low pulse level signals. The frequency of these pulse signals is proportional to the rotational speed of the magnetic rotor, and the rotational speed of the magnetic rotor is proportional to the water flow rate. Therefore, the water flow rate can be calculated by measuring the pulse signals.

[0066] When the water stops flowing, the rotor 120 moves downward along the axial direction of the outer casing 110 under the action of gravity. The second limiting structure abuts against the first limiting structure, causing the rotor 120 to stop rotating quickly. After the rotor 120 stops rotating, the Hall sensor no longer receives a rotation signal and immediately sends a signal to stop heating in the combustion chamber, thereby reducing the temperature rise of the water in the heat exchange tube and alleviating the problem of temperature rise during water outages in gas water heaters without affecting the thermal efficiency of the gas water heater. Moreover, the above solution only requires adjusting the structure of the water flow sensor, without changing the structure of other components of the existing gas water heater, making it easy to update existing models.

[0067] In some implementations, refer to Figure 4 , Figure 7 and Figure 9As shown, the lower rotor base 140 includes a lower base body 141 and a plurality of swirl vanes 142 disposed on the lower base body 141, with gaps formed between the plurality of swirl vanes 142 for water flow. The outer edges of the plurality of swirl vanes 142 are fixedly connected to the outer shell 110, and the inner edges of the plurality of swirl vanes 142 are fixedly connected to the lower base body 141. The lower base body 141 is provided with a first shaft hole 143.

[0068] Reference Figure 4 and Figure 6 As shown, the upper rotor seat 130 includes an upper seat body 131 and an annular seat 132. At least two ribs 133 are provided between the upper seat body 131 and the annular seat 132, dividing the space between the upper seat body 131 and the annular seat 132 into multiple water passage holes 134 to allow water to flow out from the outlet 112. The annular seat 132 is fastened to the outer shell 110, and the upper seat body 131 is provided with a second shaft hole 137.

[0069] In some embodiments, an annular protrusion 113 is provided on the inner wall of the outer casing 110, a mounting groove 114 is provided at the end of the outlet 112 of the outer casing 110, and a mounting protrusion 135 is provided on the outer wall of the ring seat 132. When assembling the seat 131 and the outer casing 110, the mounting protrusion 135 on the ring seat 132 is aligned with the mounting groove 114 on the outer casing 110, and then the ring seat 132 is pushed into the outer casing 110 until the ring seat 132 abuts against the annular protrusion 113 on the inner wall of the outer casing 110. (Refer to...) Figure 1 As shown.

[0070] Optionally, the upper body 131 is provided with an upper body weight reduction hole 136, and the lower body 141 is provided with a lower body weight reduction hole 144, which helps to reduce the overall weight of the water flow sensor 100 and achieve lightweighting.

[0071] Reference Figure 5A and Figure 5B As shown, the rotor 120 includes a shaft 121 and a plurality of blades 122 disposed on the shaft 121. A first pivot shaft 123 and a second pivot shaft 124 protrude from the first end and the second end of the shaft 121, respectively. The first pivot shaft 123 and the second pivot shaft 124 are respectively inserted into a first shaft hole 143 and a second shaft hole 137. The diameter of the shaft 121 is larger than the diameter of the first pivot shaft 123 and the second pivot shaft 124, such that both ends of the shaft 121 have end faces that can face the lower seat body 141 and the upper seat body 131.

[0072] It should be explained here that the structure in which the first and second ends of the rotor 120 are pivotally connected to the upper rotor seat 130 and the lower rotor seat 140, respectively, can also be provided with shaft holes at the first and second ends of the rotor 120, and the upper rotor seat 130 and the lower rotor seat 140 are correspondingly provided with pivot shafts. This utility model will not elaborate further on this aspect.

[0073] This utility model provides three implementation methods for the first limiting structure and the second limiting structure, which can be combined arbitrarily or used individually. The specific solutions of the three implementation methods are described below.

[0074] Mode 1

[0075] Reference Figures 1 to 9 In this embodiment, the first limiting structure and the second limiting structure are respectively set on the opposite end faces of the rotating shaft 121 and the lower seat 141, that is, as close to the center as possible, which helps to improve the stability of the rotor 120 when it stops rotating.

[0076] In some embodiments, the first limiting structure is at least one first limiting protrusion 125 extending radially on the end face of the rotating shaft 121, and the second limiting structure is at least one second limiting protrusion 145 extending radially on the end face of the lower seat 141. When the water flow stops, the rotor 120 will continue to rotate due to inertia, but without the support of the water flow, the rotor 120 will fall to the height of contact with the lower seat 141 under the action of gravity. When the rotor 120 continues to rotate, the sidewalls of the first limiting protrusion 125 and the sidewalls of the second limiting protrusion 145 abut against each other, causing the rotor 120 to stop rotating.

[0077] Optionally, a first limiting protrusion 125 is provided at 180° intervals along the circumferential direction on the end face of the rotating shaft 121, and correspondingly, a second limiting protrusion 145 is also provided at 180° intervals along the circumferential direction on the end face of the lower seat 141.

[0078] It should be noted that the protrusion height of the first limiting protrusion 125 and the second limiting protrusion 145 should match the axial displacement of the first pivot shaft 123 and the second pivot shaft 124 in the first shaft hole 143 and the second shaft hole 137, so as to prevent the rotor 120 from being unable to rotate under the action of water flow due to the stopping effect of the second limiting protrusion 145.

[0079] It is understandable that the swirl vanes 142 mounted on the lower body 141 promote water flow rotation, and the direction of water rotation varies depending on the tilt angle of the swirl vanes 142 relative to the axis. Based on this, referring to... Figure 4As shown, when the swirl vane 142 rotates in the first circumferential direction, the surface of the first limiting protrusion 125 smoothly transitions downward from the top of its sidewall to its root in a direction opposite to the first direction, as indicated by reference. Figure 5A As shown, the surface of the second limiting protrusion 145 smoothly transitions downward from the top of its sidewall to its root along the first direction, as indicated by reference. Figure 9 As shown. That is, when the water flow stops, under the action of inertia, the rotor 120 will rotate in the first direction while falling. At this time, when the sidewall of the first limiting protrusion 125 on the rotor 120 and the sidewall of the second limiting protrusion 145 on the lower seat 141 come into contact, the rotor 120 will quickly stop rotating. Moreover, since the transition directions of the surface of the first limiting protrusion 125 and the surface of the second limiting protrusion 145 are opposite, the surfaces of the first limiting protrusion 125 and the second limiting protrusion 145 can mesh together, which can further improve the stability of the rotor 120 when it stops rotating.

[0080] In some implementations, refer to Figure 2 and Figures 7 to 9 As shown, the lower base 141, the swirl vane 142, and the outer shell 110 are integrally formed. This greatly simplifies the production process of the water flow sensor 100, reduces the assembly steps of each component, and thus significantly improves production efficiency.

[0081] Furthermore, since the swirl vane 142 needs to withstand the impact of the water flow, molding the three components into a single piece can improve the impact resistance of the swirl vane 142, making the water flow sensor more stable and reliable when subjected to external forces or vibrations. For instruments that need to operate for extended periods or in harsh environments, this undoubtedly greatly improves their durability and service life.

[0082] Mode 2

[0083] Reference Figures 10 to 13 In this embodiment, the first limiting structure and the second limiting structure are respectively set on the opposite end faces of the first pivot shaft 123 and the first shaft hole 143, that is, as close to the center as possible, which helps to improve the stability of the rotor 120 when it stops rotating.

[0084] Specifically, the first limiting structure is a stop rib 126 provided on the end face of the first pivot shaft 123, and the stop rib 126 extends radially. The second limiting structure is a stop block 146 provided on the bottom surface of the first shaft hole 143, and the stop block 146 may be provided at the edge position.

[0085] It should be noted that the axial height of the stop rib 126 and the stop block 146 should match the axial displacement of the first pivot shaft 123 and the second pivot shaft 124 in the first shaft hole 143 and the second shaft hole 137, so as to prevent the rotor 120 from being unable to rotate under the action of water flow due to the stopping effect of the stop block 146.

[0086] When the water flow stops, the rotor 120 will continue to rotate due to inertia. However, without the support of the water flow, the rotor 120 will fall to the height of contact with the lower seat 141 under the action of gravity. When the rotor 120 continues to rotate, the side wall of the stop rib 126 and the side wall of the stop block 146 stop the rotor 120 from rotating.

[0087] Optionally, two or three stop ribs 126 can be provided radially on the end face of the first pivot shaft 123, which can speed up the process of stopping the rotor.

[0088] Mode 3

[0089] Reference Figures 14 to 16 In this embodiment, any one of the plurality of blades 122 constitutes the first limiting structure, and the second limiting structure is a stop portion 115 disposed on the inner wall of the outer casing 110.

[0090] It should be noted that the height of the stop part 115 on the inner wall of the housing 110 should match the axial displacement of the first pivot shaft 123 and the second pivot shaft 124 in the first shaft hole 143 and the second shaft hole 137, so as to prevent the rotor 120 from being unable to rotate under the action of water flow due to the stopping effect of the stop part 115.

[0091] Optionally, the bottom position of the stop portion 115 may be approximately level with or slightly higher than the top position of the swirl vane 142. The stop portion 115 may be configured as a columnar or block-shaped structure as needed, and this utility model does not impose any limitations on this.

[0092] When the water flow stops, the rotor 120 will continue to rotate due to inertia. However, without the support of the water flow, the rotor 120 will fall to the height of contact with the lower seat 141 under the action of gravity. When the rotor 120 continues to rotate, the side wall of the stop part 115 and the side wall of one of the multiple blades 122 stop the rotor 120 from rotating.

[0093] This utility model also provides a gas water heater, including a gas heating element, an inlet pipe and an outlet pipe connected to a heat exchange tube of the gas heating element. The aforementioned water flow sensor 100 is installed on the inlet pipe to detect the total inlet water flow rate entering the heat exchange tube. The control unit of the gas water heater adjusts the combustion intensity of the gas heating element according to the total inlet water flow rate to meet the user's water demand.

[0094] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A water flow sensor, comprising a housing, a rotor disposed within the housing, and a lower rotor seat, wherein the lower rotor seat is fixedly connected to the housing, and a first end of the rotor is pivotally connected to the lower rotor seat; characterized in that, The first end of the rotor is provided with a first limiting structure, and the lower rotor seat and / or the inner wall of the outer shell are provided with a second limiting structure. The rotor can move axially along the outer casing, and when the second limiting structure abuts against the first limiting structure, the rotor stops rotating.

2. The water flow sensor according to claim 1, characterized in that, The rotor includes a rotating shaft and a plurality of blades disposed on the rotating shaft; The lower rotor seat includes a lower seat body, which is fixedly connected to the outer shell and pivotally connected to the first end of the rotating shaft; The first limiting structure and the second limiting structure are respectively disposed on the opposite end faces of the rotating shaft and the lower seat.

3. The water flow sensor according to claim 2, characterized in that, The first limiting structure is at least one first limiting protrusion that extends radially on the end face of the rotating shaft, and the second limiting structure is at least one second limiting protrusion that extends radially on the end face of the lower seat. The sidewalls of the first limiting protrusion and the sidewalls of the second limiting protrusion stop the rotor from rotating.

4. The water flow sensor according to claim 3, characterized in that, The lower body is provided with a swirl vane, and the swirl vane rotates in a first direction along the circumference. Wherein, the surface of the first limiting protrusion smoothly transitions downward from the top of its sidewall to its root in a direction opposite to the first direction, and the surface of the second limiting protrusion smoothly transitions downward from the top of its sidewall to its root in the first direction.

5. The water flow sensor according to claim 4, characterized in that, The lower seat, the swirl vane, and the outer shell are integrally formed.

6. The water flow sensor according to any one of claims 1 to 5, characterized in that, The rotor includes a rotating shaft and a plurality of blades disposed on the rotating shaft; The lower rotor seat includes a lower seat body, which is fixedly connected to the outer shell; One of the lower seat body and the first end of the rotating shaft is provided with a pivot shaft, and the other of the lower seat body and the first end of the rotating shaft is provided with a pivot hole, and the pivot shaft is pivotally connected to the pivot hole; The first limiting structure and the second limiting structure are respectively disposed on the opposite end faces of the pivot shaft and the pivot hole.

7. The water flow sensor according to claim 6, characterized in that, The first limiting structure and the second limiting structure are respectively a stop rib and a stop block disposed on the end faces opposite to the pivot shaft and the pivot hole.

8. The water flow sensor according to any one of claims 1 to 5, characterized in that, The rotor includes a rotating shaft and a plurality of blades disposed on the rotating shaft; The lower rotor seat includes a lower seat body, which is fixedly connected to the outer shell and pivotally connected to the first end of the rotating shaft; Any one of the plurality of blades constitutes the first limiting structure, and the second limiting structure is a stop portion disposed on the inner wall of the outer casing.

9. The water flow sensor according to any one of claims 2 to 5, characterized in that, It also includes an upper rotor seat fixedly connected to the housing, the upper rotor seat being pivotally connected to the second end of the rotating shaft.

10. A gas-fired water heater, characterized in that, Includes a water flow sensor according to any one of claims 1 to 9.

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