Range hood and cleaning reminding method thereof

Abstract

The invention relates to a range hood and a control method of the range hood, the range hood comprises a centrifugal fan, the centrifugal fan comprises a volute and a current collector, the volute comprises a front side plate, an air inlet is formed in the front side plate, and the current collector is connected to the air inlet of the front side plate; the current collector comprises an annular flow guide part and a connecting ring extending outwards from the flow guide part in the radial direction, and further comprises a locking rotary knob rotationally arranged on the connecting ring and used for locking the connecting ring and a front side plate of the volute, and a magnet capable of rotating along with the locking rotary knob is further arranged on the portion, located on the front side of the connecting ring, of the locking rotary knob. The volute is further provided with a Hall sensor, the Hall sensor is electrically connected with a control system of the range hood, the control system judges the amount of oil dirt attached to the centrifugal fan according to the variable quantity of a magnetic field signal transmitted by the Hall sensor, and then cleaning reminding is given out through an alarm device. The method has the advantages that oil contamination amount detection is more accurate, and the misjudgment condition of cleaning reminding can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of range hoods, and particularly relates to a range hood and a cleaning reminder method for the range hood. Background Art

[0002] A range hood is a kitchen appliance for purifying the kitchen environment. A range hood generally includes a fan system, a control system, an oil filtering device, a housing, a suspension device, etc. The fan system of the range hood mainly includes parts such as a volute, an impeller, and a motor. Since cooking fumes need to be discharged through the fan system, this will inevitably cause a certain amount of oil stains to remain on the impeller and the volute. If not cleaned for a long time, the cooking fumes will accumulate to form dirt, which will not only block the air inlet channels between the blades, resulting in performance degradation and affecting smoke exhaust and cooking, but also the accumulated oil stains over a long time may affect the air environment in the kitchen, posing a potential hazard to the physical and mental health of users. At present, most types of range hoods on the market do not have an oil stain detection function and cannot effectively and accurately determine the time for deep cleaning of the range hood. A small number of range hoods use an oil stain detection technology that records the working duration of the range hood and then reminds the user to clean based on the working duration. However, there are differences in cooking methods in different regions, and the amount of cooking fumes generated by different cooking methods at the same time is often different, which will result in different amounts of oil stains remaining on the impeller and the volute. Using the method of time accumulation often has a very large deviation.

[0003] For this reason, the Chinese invention patent application with the application number CN202310904681.3 discloses a method for detecting the state of an impeller of a range hood, including the following steps: Start the range hood, control the impeller speed in the range hood to reach the target speed from the starting speed of 0, and record the first time t1 from startup to when the impeller speed reaches the target speed; Turn off the range hood and record the second time t2 from shutdown to when the impeller speed reaches the starting speed of 0; Based on the time difference between t1 and the first time threshold corresponding to a brand-new impeller, and the time difference between t2 and the second time threshold corresponding to a brand-new impeller, further judge the oil contamination condition of the impeller and the balance state of the impeller. This state detection method is based on the fact that under different oil contamination states on the impeller, the time required for it to start up to the set speed, or after stopping from the set speed, is different. Therefore, by counting the startup and shutdown times of the impeller, the oil contamination state and the balance state of the impeller are determined, which is conducive to determining a more accurate impeller state, so as to adopt corresponding measures to restore the normal use state of the impeller. The above oil contamination detection method is greatly affected by external interference factors. For example, during the operation of the impeller, the load of the connected equipment may change. If the impeller is used in a ventilation system, the resistance in the ventilation duct may change due to factors such as dust accumulation and valve opening changes. When the load increases, the time required for the impeller to start up to the set speed will become longer, and the time required to stop will also be affected. This change may mask the influence of the oil contamination state on the startup and shutdown times, resulting in misjudgment. In addition, to accurately judge the oil contamination state through the startup and shutdown times of the impeller, a very high precision requirement is imposed on time measurement. Moreover, it is very difficult to establish an accurate quantitative standard just by judging the oil contamination state through the startup and shutdown times. For impellers of different types, sizes, and speeds, the variation range of the startup and shutdown times corresponding to their oil contamination states may be different. In this way, under the same degree of oil contamination, the variation of the startup and shutdown times may vary greatly, and it is very difficult to measure the oil contamination state with a unified time standard.

[0004] There is also a way to achieve the cleaning reminder of the range hood by detecting different values of the wind pressure detection. For example, the Chinese invention patent application with the application number CN202210450445.4 proposes a range hood cleaning reminder system, method and variable-frequency range hood, including an oil net, a fan and an exhaust component connected in sequence. By obtaining the first fan operation parameters corresponding to the exhaust gear represented by the exhaust gear command, the fan operation parameters include the fan power and the fan speed, which are detected by a pressure sensor, and calculating the difference between the preset second fan operation parameters and the first fan operation parameters. When the difference meets the preset reminder threshold, a reminder command is sent to the user interaction module. After receiving the reminder command, the user interaction module sends a cleaning reminder corresponding to the oil net or the exhaust component to the user. However, this method of judging whether the fan needs to be cleaned by detecting the pressure of the air valve at the connection between the smoke pipe and the common flue through a pressure sensor also has certain problems. Since the pressure pulsation at the pressure detection point is small and the change is insensitive, the monitoring sensitivity is lacking, so it cannot be timely and accurately reminded.

[0005] Therefore, the existing range hoods and their cleaning reminder methods still need to be further improved. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide a range hood with more accurate detection of the amount of oil stain and capable of effectively reducing the misjudgment of the cleaning reminder in view of the current situation of the prior art.

[0007] The second technical problem to be solved by the present invention is to provide a cleaning reminder method for a range hood with more accurate detection of the amount of oil stain and capable of effectively reducing the misjudgment of the cleaning reminder in view of the current situation of the prior art.

[0008] The technical solution adopted by the present invention to solve the first technical problem is as follows:

[0009] A range hood includes a centrifugal fan. The centrifugal fan includes a volute and an air collector detachably installed on the volute. The volute includes a front side plate, a rear side plate and an annular wall connecting between the front side plate and the rear side plate. An air inlet is opened on the front side plate. The air collector is connected to the air inlet of the front side plate. The air collector includes an annular guide portion and a connecting ring extending radially outward from the guide portion. It further includes a locking knob rotatably arranged on the connecting ring for locking the connecting ring and the front side plate of the volute. A magnet capable of rotating together with the locking knob is further provided on the part of the locking knob located on the front side of the connecting ring. A Hall sensor is also provided on the volute. The Hall sensor is electrically connected to the control system of the range hood. The control system judges the amount of oil stain attached to the centrifugal fan according to the change amount of the magnetic field signal transmitted by the Hall sensor, and then sends a cleaning reminder through an alarm device.

[0010] The above-mentioned "change amount of the magnetic field signal transmitted by the Hall sensor" may refer to the magnetic field signal difference obtained by comparing the magnetic field signal U currently transmitted by the Hall sensor with the magnetic field signal Us after the last cleaning is completed, or the magnetic field signal change value associated with the difference.

[0011] As an improvement, the alarm device is an alarm capable of emitting sound and / or light, or a display screen capable of displaying a cleaning reminder message.

[0012] Generally speaking, the Hall sensor can be arranged inside the volute. However, considering that the amount of oil fume inside the volute is relatively large, there may be a situation where the magnetic field signal is interrupted due to the oil fume accumulated in a short time. Therefore, the Hall sensor should be placed in an environment with too much oil fume. An installation frame is provided on the outer side of the annular wall of the volute, and an installation cavity for placing the Hall sensor is defined on the installation frame.

[0013] In order to realize the flexible disassembly and locking between the collector and the volute, the locking knob has a laterally protruding limit buckle on the part located at the rear side of the connecting ring. A through hole is opened on the front side plate in the front-rear direction. The limit buckle of the locking knob can pass through the limit hole and can be rotated and switched between a first position opposite to the limit hole and a second position misaligned with the limit hole. When the locking knob is in the above-mentioned first position, in the rotation direction of the locking knob, the magnet on the locking knob is far away from the Hall sensor; when the locking knob is in the above-mentioned second position, in the rotation direction of the knob, the magnet on the locking knob is close to the Hall sensor.

[0014] In order to facilitate the installation and rotation of the locking knob on the connecting ring, a shaft hole is provided on the connecting ring. The locking knob includes a knob body, a locking rod and a locking part. The knob body and the locking part are respectively located on the front and rear sides of the connecting ring and are connected by a locking rod passing through the shaft hole. The locking part includes a connecting column and a limit buckle extending laterally from the connecting column. The locking rod and the knob body are detachably connected, and the first end of the locking rod and the knob body can be limited in the axial and circumferential directions of the locking rod. The magnet is arranged on the knob body.

[0015] To simplify the detachable assembly structure among the lock rod, the lock fastener, and the knob body, an axially opened movable channel is provided on the connecting column. The second end of the lock rod is slidably disposed in the movable channel, and the second end of the lock rod and the inner wall of the movable channel are circumferentially limited by a keyway fit. The first end of the lock rod has a limiting pin shaft protruding radially outward. The interior of the knob body defines a locking chamber, and a first mounting opening is provided on the side facing the lock fastener for the first end of the lock rod and its limiting pin shaft to extend into the locking chamber. An elastic member is further provided in the movable channel, which acts on the lock rod and makes the lock rod always have a tendency to move axially away from the knob body. A limiting card slot is provided on the inner wall of the locking chamber adjacent to the first mounting opening. After the limiting pin shaft of the lock rod passes through the first mounting opening and enters the locking chamber and rotates a certain angle, it can be snapped into the limiting card slot under the action of the elastic member.

[0016] To avoid the connecting ring of the current collector from affecting the induction sensitivity between the magnet and the Hall sensor on the locking knob, the knob body includes a limiting disc located on the front side of the connecting ring and a knob operation portion protruding from the front side of the limiting disc. When the locking knob is in the second position state, a part of the limiting disc is exposed outside the outer peripheral edge of the connecting ring, and the magnet is provided on the inner side of the part of the limiting disc exposed outside the outer peripheral edge of the connecting ring.

[0017] To adapt to the rotation action of the locking knob and further improve the induction sensitivity between the magnet and the Hall sensor on the locking knob, a connecting channel is further provided on the side of the knob body facing the lock fastener. A first mounting opening communicating with the locking chamber is provided on the bottom wall of the connecting channel. A fixed sleeve is further provided at the shaft hole position on the side of the connecting ring facing the knob body. The lock rod passes through the fixed sleeve and is connected to the knob body. The fixed sleeve extends into the connecting channel, and the outer peripheral wall of the fixed sleeve and the inner peripheral wall of the connecting channel are threadedly connected, so that the knob body can move axially closer to or away from the connecting ring when rotating forward and backward. When the locking knob is in the first position, the locking knob is axially away from the connecting ring. When the locking knob is in the second position, the locking knob is axially close to the connecting ring.

[0018] To avoid the adverse effect of the presence of the front panel on the induction sensitivity between the magnet and the Hall sensor, it further includes a casing. The centrifugal fan is arranged inside the casing. The casing includes a front panel. The front panel has a third mounting opening opposite to the air inlet of the volute. The connecting ring of the air collector abuts against the front side of the peripheral edge of the third mounting opening. A first through hole opposite to the limiting hole and through which the rear end of the locking knob and the limiting buckle provided on its rear end can pass is formed on the peripheral edge of the third mounting opening. A second through hole is further formed on the peripheral edge of the third mounting opening. The second through hole is opposite to the magnet on the locking knob in the second position state front and back.

[0019] To minimize the entry of flue gas through the second through hole into the position where the electromagnetic lock is located and avoid the electromagnetic lock being contaminated by oil and grease, it further includes a baffle plate rotatably arranged inside the front panel. The baffle plate and the locking knob are linked through a transmission component, so as to drive the baffle plate to rotate during the rotation of the locking knob. When the locking knob is in the first position, the baffle plate closes the second through hole. When the locking knob is in the second position, the baffle plate opens the second through hole.

[0020] To further achieve a reliable lock between the air collector and the volute, a self-locking device is further provided on the volute. The self-locking device includes an electromagnetic lock. The electromagnetic lock includes a locking tongue. One side of the locking knob facing the electromagnetic lock has a locking position. The electromagnetic lock is electrically connected to the control system of the range hood. The Hall sensor identifies the rotation position of the locking knob through the induction cooperation with the magnet. Thus, when the locking knob is in the second position, the control system controls the locking tongue of the electromagnetic lock to move towards the locking position of the locking knob to form a limiting fit.

[0021] The technical solution adopted by the present invention to solve the second technical problem is: a cleaning reminder method for a range hood, including the following steps: starting the cleaning detection program of the range hood, the control system compares the current magnetic field signal U transmitted by the Hall sensor with the magnetic field signal Us after the last cleaning is completed to obtain the magnetic field signal change value ΔU, and then compares ΔU with the set magnetic field change threshold to judge the degree of oil and grease pollution of the centrifugal fan, and then issues a corresponding reminder through the alarm device.

[0022] As an improvement, the cleaning reminder method of the range hood also includes determining whether the user has performed the disassembly and cleaning steps of the impeller during the current startup cycle. If so, after the disassembly and cleaning are completed and installed in place, the magnetic field signal newly transmitted by the Hall sensor is recorded as the magnetic field signal Us for comparison next time. If not, the method returns to the initial step and waits for the next cleaning detection program of the range hood to be started, or a corresponding reminder is still issued through the alarm device after the range hood is started next time.

[0023] As an improvement, the range hood cleaning reminder method further includes the following steps: the magnetic field signal change value ΔU is:

[0024]

[0025] If △U≤U1, it is judged as light pollution, and a cleaning reminder is given by flashing the indicator light, while the functions of the range hood are normal and available. Then it is judged whether the user has disassembled and cleaned the impeller. If the impeller has been disassembled and cleaned, after the disassembly and cleaning are completed and installed in place, the magnetic field signal transmitted by the new Hall sensor is recorded. If the impeller has not been disassembled and cleaned, the initial step is returned to wait for the next cleaning detection program of the range hood to start;

[0026] If U1 < △U < U2, it is judged as moderate pollution, and a cleaning reminder is given by flashing indicator lights and emitting sounds. The functions of the range hood are normally available during this startup cycle. Then it is judged whether the user has disassembled and cleaned the impeller. If it has been disassembled and cleaned, after the disassembly and cleaning are completed and installed in place, the magnetic field signal transmitted by the new Hall sensor is recorded. If it has not been disassembled and cleaned, it returns to the initial step and waits for the next cleaning and detection program of the range hood to start;

[0027] If △U≥U2, it is judged as heavy pollution, and a cleaning reminder is given by flashing indicator lights and making sounds. The range hood functions normally during this startup cycle. It is then judged whether the user has disassembled and cleaned the impeller. If it has been disassembled and cleaned, the magnetic field signal transmitted by the new Hall sensor is recorded after the disassembly and cleaning is completed and installed in place. If it has not been disassembled and cleaned, the range hood function will be unavailable after the next startup, and the user is required to force the disassembly and cleaning process or remove the restriction on the unavailability of the range hood function through other operations.

[0028] As an improvement, the cleaning reminder method of the range hood determines whether the user has disassembled the impeller for cleaning by: whether the Hall sensor has reacquired the magnetic field signal within a set time after losing the magnetic field signal. During the impeller disassembly and cleaning process, the collector will be rotated to unlock and remove, and after cleaning, the collector will be installed and locked. During this process, the magnetic induction signal of the Hall sensor is detected to have obvious changes. When the user is cleaning, the collector will be disassembled, and the Hall sensor will lose the magnetic field signal first, and then receive the magnetic field signal after installation.

[0029] As an improvement, the operating steps for removing the restriction on the unavailability of the range hood function in the cleaning reminder method of the range hood are: long pressing the corresponding operation button on the range hood.

[0030] As an improvement, the cleaning reminder method for the range hood also includes the following steps: after the range hood is turned on, the range hood automatically enters the cleaning detection program of the range hood.

[0031] As an improvement, in order to avoid the range hood from performing a cleaning and detection procedure every time it is turned on, the cleaning reminder method of the range hood also includes the following steps: after the range hood is turned on, the effective working time of the range hood from the last disassembly and cleaning operation is determined, and after the effective working time reaches the set time, the cleaning and detection procedure of the range hood is entered; if the effective working time reaches the set time, the cleaning and detection procedure of the range hood is not entered.

[0032] Compared with the prior art, the advantages of the present invention are as follows: the magnet provided on the locking knob for locking the connecting ring and the front side plate of the volute can form an inductive match with the Hall sensor provided on the volute, and oil stains will adhere to the components between the magnet and the Hall sensor after the range hood is used, and the magnetic field signal received by the Hall sensor will change due to the different amounts of oil stains adhered, thereby, the control system determines the amount of oil stains adhered to the centrifugal fan according to the amount of change in the magnetic field signal transmitted by the Hall sensor, and then issues a cleaning reminder through the alarm device. This range hood and cleaning reminder method quantifies the thickness of the oil stains through the change in the magnetic field received by the Hall sensor, and can achieve accurate measurement of the amount of oil stains. Compared with traditional cleaning reminders based on time or fixed cycles, this method is relatively less affected by external factors, can more accurately reflect the actual situation of the oil stains, and reduces false alarms caused by different degrees of oil stains. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic diagram of the three-dimensional structure of a range hood according to an embodiment of the present invention;

[0034] Figure 2 is a cross-sectional view of a range hood according to an embodiment of the present invention;

[0035] Figure 3 Cross-sectional view of the current collector according to an embodiment of the present invention;

[0036] Figure 4 Exploded view of the locking knob of the current collector according to an embodiment of the present invention;

[0037] Figure 5 Cross-sectional view of the components of the locking knob of the current collector according to an embodiment of the present invention in a disassembled state;

[0038] Figure 6 Schematic perspective view of the inner side of the centrifugal fan according to an embodiment of the present invention;

[0039] Figure 7 Schematic perspective view of the front panel of the casing according to an embodiment of the present invention;

[0040] Figure 8 Partial sectional perspective view of the range hood according to an embodiment of the present invention;

[0041] Figure 9 Schematic perspective view of the back of the front panel according to an embodiment of the present invention (the locking knob is in the unlocked state);

[0042] Figure 10 Schematic perspective view of the back of the front panel according to an embodiment of the present invention (the locking knob is in the locked state);

[0043] Figure 11 Control flowchart of the cleaning reminder method for the range hood according to an embodiment of the present invention. Detailed implementation manners

[0044] The present invention will be further described in detail below in conjunction with the embodiments with reference to the accompanying drawings.

[0045] In the description and claims of the present invention, terms indicating directions such as "front", "rear", "upper", "lower", "left", "right", "side", "top", "bottom", etc. are used to describe various exemplary structural parts and elements of the present invention. However, these terms are used here only for the convenience of description and are determined based on the exemplary orientations shown in the drawings. Since the embodiments disclosed by the present invention can be arranged in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations. For example, "upper" and "lower" are not necessarily limited to the directions opposite to or consistent with the direction of gravity.

[0046] Figures 1-11Shows a preferred embodiment of the range hood of the present invention and the cleaning reminder method of the range hood. The range hood includes a housing 5 and a centrifugal fan disposed within the housing 5. An air inlet 110 is formed on the front side wall (i.e., the front panel 51) of the housing 5, and external flue gas can enter the housing 5 through the air inlet 110. When the centrifugal fan operates, a negative pressure is generated, and external cooking fumes can be sucked into the housing 5 through the air inlet 110. An oil cup 54 extending left and right is further provided at the bottom of the housing 5 for receiving the oil flowing down from the housing 5. A smoke baffle 53 that can deflect forward and backward relative to the housing 5 is further provided at the front of the housing 5. The smoke baffle 53 is connected to the main body of the housing 5 through a hinge movement mechanism, and specifically can deflect forward to open the above-mentioned air inlet and deflect backward to block and close the above-mentioned air inlet. The hinge movement mechanism for driving the deflection of the smoke baffle can adopt a conventional hinge movement mechanism in the prior art, which will not be elaborated here.

[0047] See Figure 2 , the centrifugal fan includes a volute 1, an impeller 21 rotatably disposed within the volute 1, and a motor 22 for driving the impeller 21 to rotate. The volute 1 includes a front side plate 11, a rear side plate 12, and an annular wall 13 connecting the front side plate 11 and the rear side plate 12. A corresponding air inlet 110 is formed on the front side plate 11 of the volute 1. A collector is provided at the air inlet 110 of the front side plate 11 of the volute 1. The collector includes an annular flow guiding portion 31 and a connecting ring 32 extending radially outward from the flow guiding portion 31. Among them, the flow guiding portion 31 of the collector generally includes a radially extending flow guiding portion 31 with an arc-shaped cross-section and an axially extending flow guiding portion 31 extending circumferentially from the inner side of the radially extending flow guiding portion 31. A filter screen 30 is further provided at the central opening of the flow guiding portion 31 of the collector. The connecting ring 32 of the collector is a flat annular plate structure and can be attached to the outer peripheral edge of the air inlet 110 of the front side plate of the volute 1. A filter screen 30 is further attached to the inner opening of the flow guiding portion 31 of the collector for filtering cooking fumes and balancing the air flow.

[0048] See Figure 3, at the outer peripheral edge of the connecting ring 32 of the current collector of this embodiment, there is a convex ear portion 321 extending outward. A locking knob 4 is rotatably provided at the convex ear portion 321. The locking knob 4 includes a knob body 40, a locking member 43, and a locking rod 46. The knob body 40 includes a limiting disc 42 and a knob operation portion 41 protruding from the front side of the limiting disc 42. Among them, the knob operation portion 41 is a cross-shaped knob. An axial hole 3210 for the locking rod 46 to pass through is formed on the convex ear portion 321 of the connecting ring 32. The locking member 43 includes a connecting column 44 and a limiting buckle 45 extending from the connecting column 44 to the side. The knob body 40 and the connecting column 44 of the locking member 43 are respectively located on the front and rear sides of the connecting ring 32 and are connected by a locking rod 46 passing through the axial hole 3210. The connection between the locking rod 46 and the knob body 40 is detachable, and the first end of the locking rod 46 and the knob body 40 can be limited in the axial and circumferential directions of the locking rod 46. The second end of the locking rod 46 and the connecting column 44 of the locking member 43 are detachably connected, and the second end of the locking rod 46 and the locking member 43 can be limited in the axial and circumferential directions of the locking rod 46.

[0049] See Figures 3-5, in order to simplify the detachable assembly structure among the lock rod 46, the lock fastener 43 and the knob body 40, an axially opened movable channel 440 is provided on the connecting column 44. The second end of the lock rod 46 is slidably disposed in the movable channel 440, and the second end of the lock rod 46 and the inner wall of the movable channel 440 are circumferentially limited by means of keyway fit. Specifically, on the outer peripheral wall of the second end of the lock rod 46, there are two outwardly protruding convex keys 463 which are symmetrically arranged. On the inner peripheral wall of the movable channel 440, there are two corresponding sliding grooves 441 opened along its length direction. The two convex keys 463 are respectively slidably limited in the two sliding grooves 441 of the movable channel 440. Through the cooperation of the convex keys 463 and the sliding grooves 441, on the one hand, the circumferential limitation between the lock rod 46 and the lock fastener 43 can be realized, so that when the lock rod 46 rotates, it can drive the lock fastener 43 to rotate; on the other hand, the stability of the relative movement between the lock rod 46 and the lock fastener 43 in the axial direction can be ensured. On the outer peripheral wall of the second end of the lock rod 46, there is also an outwardly protruding limit stop portion 462, and the outer edge of the limit stop portion 462 is circular. The above-mentioned convex keys 463 are correspondingly arranged at the outer edge of the limit stop portion 462. At one end of the connecting column 44 of the lock fastener 43 away from the knob body 40, there is a second mounting opening 442 communicating with the movable channel 440. At one end of the connecting column 44 facing the knob body 40, there is a through hole 443 communicating with the movable channel 440. The lock rod 46 can be inserted into the movable channel 440 through the second mounting opening 442, and the first end of the lock rod 46 extends out through the through hole 443. Among them, the diameter of the through hole 443 is adapted to the outer diameter of the main body of the lock rod 46, but is smaller than the outer diameter of the limit stop portion 462 on the lock rod 46. Thus, the periphery of the through hole 443 can be used to limit the axial movement of the lock rod 46. An elastic member 47 is also provided in the movable channel 440 of the lock fastener 43. The elastic member 47 is a spring and is sleeved outside the lock rod 46. The first end of the spring abuts against the limit stop portion 462 of the lock rod 46, and the second end abuts against the peripheral edge of the through hole 443 of the movable channel 440. Under the elastic force of the elastic member 47, the lock rod 46 always has a tendency to move axially away from the knob body 40.

[0050] The first end of the lock rod 46 has a limit pin shaft 461 protruding radially outward. The limit pin shaft 461 can be integrally provided on the first end of the lock rod 46 or can be installed on the first end of the lock rod 46 in the form of a separate part.

[0051] The interior of the limit disk 42 of the knob body 40 defines a locking chamber 420, and on the side facing the locking member 43, a first mounting opening 422 is provided through which the first end of the locking rod 46 and its limit pin 461 can extend into the locking chamber 420. The first mounting opening 422 is a strip-shaped opening. On the inner wall of the locking chamber 420, a limit card slot 421 is provided adjacent to the first mounting opening 422. The limit card slot 421 is a strip-shaped card slot and is circumferentially misaligned with the above-mentioned first mounting opening 422. After the limit pin 461 of the locking rod 46 passes through the first mounting opening 422 and enters the locking chamber 420 and rotates a certain angle, it can be snapped into the limit card slot 421 under the action of the elastic member 47, thereby realizing the axial tension between the knob body and the locking member 43.

[0052] On the side of the knob body 40 facing the locking member 43, a connecting channel 423 is further provided, and the above-mentioned first mounting opening 422 is provided on the bottom wall of the connecting channel 423. On the side of the connecting ring 32 facing the knob body 40, a fixing sleeve 48 is further provided at the position of the shaft hole 3210. The fixing sleeve 48 can be embedded in the shaft hole 3210 of the connecting ring 32 or can be fixed on the side of the connecting ring 32 facing the knob body 40 by means of bonding. The locking rod 46 passes through the fixing sleeve 48 and is connected to the knob body 40. Specifically, the size and shape of the connecting channel 423 of the knob body 40 are adapted to the outer contour of the fixing sleeve 48. The fixing sleeve 48 can extend into the connecting channel 423, and the outer peripheral wall of the fixing sleeve 48 is threadedly connected to the inner peripheral wall of the connecting channel 423. Thus, when the knob body 40 rotates forward and backward, it can approach or move away from the connecting ring 32 under the adjustment of the thread.

[0053] The limit buckle 45 of the locking member 43 protrudes radially outward from the peripheral wall of the connecting column 44, and there is a certain gap between the front end of the limit buckle 45 and the limit disk 42 of the knob body 40. In a preferred embodiment, the limit buckle 45 is a rib plate structure extending along the axial direction of the connecting column 44, and the dimension of the limit buckle 45 protruding outward relative to the connecting column 44 gradually increases from back to front, that is, the outer edge of the limit buckle 45 forms a guiding slope, so that the limit buckle 45 can conveniently pass through the limit hole 111 of the front side plate of the volute 1 backward during installation.

[0054] A limiting hole 111 penetrating through the front and back is formed in the front side plate of the volute 1. The limiting buckle 45 of the locking knob 4 can pass through the above-mentioned limiting hole 111 backward, and after rotating a certain angle, it is limited at the rear side of the outer peripheral edge of the limiting hole 111 on the front side plate. Specifically, as the relative rotational position of the locking knob 4 with respect to the connecting ring 32 changes, the locking knob 4 at least has a locked state in which the limiting buckle 45 is limited at the rear side of the outer peripheral edge of the limiting hole 111 to prevent the limiting buckle 45 from being disengaged from the limiting hole 111 forward, and an unlocked state in which the limiting buckle 45 is moved to a position opposite to the limiting hole 111 to allow the limiting buckle 45 to be disengaged from the limiting hole 111 forward. As can be seen from the foregoing, during the rotation of the knob body 40 from the unlocked position to the locked position, the knob body 40 approaches the connecting ring 32 under screw adjustment; during the rotation of the knob body 40 from the locked position to the unlocked position, the knob body 40 moves away from the connecting ring 32 under screw adjustment.

[0055] See Figure 6 , in order to effectively indicate the locked position state during the rotation of the locking knob 4 and further improve the installation efficiency of the collector, two positioning protrusions are also provided on the side wall surface of the front side plate of the volute facing the inside of the volute 1 at intervals along the circumferential direction of the locking knob 4. When the locking knob 4 is in the locked state, the limiting buckle 45 is limited between the two positioning protrusions 112. Among them, the distance between the two positioning protrusions 112 is adapted to the thickness of the limiting buckle 45 of the locking knob 4. Thus, the left-right swing of the limiting buckle 45 can be effectively restricted, so that the locking knob 4 can be stably maintained in the locked state. The top of the above-mentioned positioning protrusion 112 can adopt a smooth convex outer surface design, so that the front end of the limiting buckle 45 can smoothly cross the opposite positioning protrusion during the rotation of the locking knob 4 and be limited between the two positioning protrusions. The design of the limiting protrusion 112 can also indicate the feel of the locking knob 4 when it rotates in place, improving the user experience.

[0056] In this embodiment, the outer peripheral edge of the connecting ring 32 has an outwardly extending insertion pin 322, and a first positioning socket 113 for inserting the insertion pin 322 is formed on the front side plate. The position where the insertion pin 322 is connected to the connecting ring 32 is inclined backward to form a limiting step. After the insertion pin 322 of the collector is installed in place, the setting of the above-mentioned limiting step allows the collector to deflect backward around the position of the insertion pin 322, so that the connecting ring 32 of the collector can better abut against the outer side plate of the volute 1. In order to prevent air leakage and uneven force at other positions after the collector is installed, there are two insertion pins 322 for the collector in this embodiment, and the positions where the two insertion pins 322 are located and the position where the locking knob 4 is located are respectively on opposite sides of the connecting ring 32, thereby ensuring the reliability of the installation of the collector.

[0057] See Figure 6 and Figure 7, the housing 5 of the range hood includes a front panel 51. Among them, the front panel 51 has a third installation opening 511 opposite to the air inlet 110 of the volute 1, and the third installation opening 511 is also a circular or quasi-circular structure that fits. In order to conveniently guide the flue gas, the outer peripheral edge of the front panel 51 to the position where the third installation opening 511 is located is an arc surface structure that gradually slopes backward, and the peripheral edge part of the third installation opening 511 is a flat surface structure. The connecting ring 32 of the collector abuts against the front side of the peripheral edge of the third installation opening 511 of the front panel 51, that is, the peripheral edge of the third installation opening 511 is embedded between the connecting ring 32 of the collector and the front side plate of the volute 1. A first through hole 512 for the locking fastener 43 and the locking rod 46 to pass through is provided on the peripheral edge of the third installation opening 511, and the first through hole 512 is opposite to the limiting hole 111. Among them, the shape and size of the first through hole 512 are basically the same as those of the limiting hole 111. With this structural design, it is possible to install and disassemble the collector without disassembling the front panel 51 of the housing 5, thus facilitating the cleaning operation of the inside of the impeller 21 and the volute 1.

[0058] A second positioning socket 513 is also provided at the peripheral edge of the third installation opening 511 of the front panel 51 of the housing 5. The second positioning socket 513 is opposite to the first positioning socket 113 on the front side plate of the volute 1 in the front-rear direction. When installing the collector, the pin 322 on the connecting ring 32 of the collector can pass through the second positioning socket 513 and be inserted into the first positioning socket 113 of the volute 1.

[0059] Continue to refer to Figure 2 , a sealing ring 52 is also provided between the peripheral edge of the third installation opening 511 of the front panel 51 and the front side plate of the volute 1. The peripheral edge of the air inlet 110 of the front side plate of the volute 1 has a second flanging 114 that folds forward. The inner edge of the sealing ring 52 has a protruding part 521 that protrudes laterally, so that the cross-section of the sealing ring 52 is stepped. Among them, the protruding part 521 of the sealing ring 52 is clamped between the second flanging 114 and the peripheral edge of the third installation opening 511 of the panel, and the other parts of the sealing ring 52 except the protruding part 521 are clamped between the peripheral edge of the third installation opening 511 of the front panel 51 and the front side plate of the volute 1. The above installation structural design of the sealing ring 52 can effectively ensure the sealing between the front panel 51 and the volute 1 and make the two abut against each other to reduce vibration and noise problems.

[0060] The side of the sealing ring 52 facing the volute 1 has at least two positioning posts 522 arranged in sequence along the circumferential direction. At least two positioning holes 115 for each positioning post 522 to be correspondingly inserted into are provided on the front side plate of the volute 1. After the sealing ring 52 is embedded in the positioning holes 115 of the front side plate of the volute 1 through the positioning posts 522, the reliability of the installation of the sealing ring 52 and the accuracy of the installation position can be ensured, and the installation efficiency is improved.

[0061] The outer peripheral edge of the connecting ring 32 of the current collector also has a first flanging 323 that bends backward. The height of the first flanging 323 can be about 2-3 mm. When the current collector is in the installed position, the first flanging 323 can abut against the peripheral edge of the third mounting opening 511 of the front panel 51 to increase the strength of the non-loaded position of the current collector, ensure the overall flatness, and thus be able to better contact the volute 1. To further reduce the air leakage problem, the side surface of the connecting ring 32 facing the volute 1 is in close contact with the convex portion 521 of the sealing ring 52.

[0062] In this embodiment, the current collector is connected to the front side plate of the volute 1 by using the locking knob 4. When the current collector needs to be installed on the front side plate of the volute 1, only the limit buckle 45 of the locking knob 4 needs to pass through the limit hole 111 on the front side plate of the volute 1 and then rotate a certain angle. The limit buckle 45 can be limited to the rear side of the outer peripheral edge of the limit hole 111 and will not protrude forward out of the limit hole 111 and is in the locked state. When the current collector needs to be disassembled, the locking knob 4 is rotated to a position where the limit buckle 45 is opposite to the limit hole 111. In this way, the limit buckle 45 can protrude forward from the limit hole 111 to achieve unlocking. The locking and unlocking method through the locking knob 4 is more convenient for the operator to operate, the disassembly process is more labor-saving, and it is not easy to loosen or become loose due to the movement and vibration of the fan, ensuring the reliability of the connection between the current collector and the front side plate of the volute 1.

[0063] See 8- Figure 10, a part of the limit disk 42 of the locking knob 4 protrudes from the outer peripheral edge of the connecting ring 32. A magnet 424 is provided on the side of the part of the limit disk 42 protruding from the outer peripheral edge of the connecting ring 32 facing the position where the volute 1 is located. In order to realize the installation in-place detection and safety locking of the collector, an electromagnetic lock 6 and a Hall sensor 64 are also provided outside the ring wall 13 of the volute 1 adjacent to the locking knob 4. Since the magnet 424 is provided on the locking knob 4, the rotation of the locking knob 4 will drive the magnet 424 to move. When the locking knob 4 is rotated to the right to reach the limit position, the magnet 424 will transmit a signal to the rear Hall sensor 64 (or reed switch). After the Hall senses the magnetic field of the magnet 424, it will send a signal, and then the system will energize the electromagnetic lock 6. The locking tongue 61 of the electromagnetic lock 6 will move upward (a third through hole 515 for the locking tongue 61 to pass through is provided on the front panel 51), and perform locking cooperation with the locking position 425 on the knob body 40 of the locking knob 4 to realize the locking of the locking knob 4. At this time, the range hood can work normally. If the locking knob 4 is not rotated in place, it means that the collector is not installed reliably, and the Hall sensor 64 will not be triggered. At this time, the range hood system is powered off and the impeller 21 will not rotate, which can avoid the risk of the user touching the rotating impeller 21 during the disassembly process due to the unreliable installation of the collector. Specifically, there is a mounting bracket 62 on the side of the volute 1. There is a protective cover inside the mounting bracket 62, and the electromagnetic lock 6 and the Hall sensor 64 are installed inside. The internal space of the protective cover is the placement cavity for placing the Hall sensor 64. The setting of the protective cover can effectively reduce the pollution of the components by the oil fume and is fastened by screws inside. The electromagnetic lock 6 has also been treated against oil pollution. Specifically, a retractable rubber oil-proof sleeve 63 structure is used. The oil-proof sleeve 63 is conical as a whole. Its small head is stuck in the card slot of the locking tongue 61 of the electromagnetic lock 6, and the other large head side is stuck in the card slot of the plastic shell of the electromagnetic lock 6, so that the inside of the electromagnetic lock 6 can be oil-proof.

[0064] The "locking position" of the locking knob 4 can be a groove or socket structure provided on the locking knob, which can be inserted into the end of the locking tongue 61 of the electromagnetic lock, so as to form a limit in the circumferential direction.

[0065] The Hall sensor 64 mainly relies on the magnetic field of the induction magnet 424 and then releases an electrical signal, but its induction is affected by the size of the magnet 424 and the distance from the magnet 424. Since the magnet 424 on the knob body 40 and the Hall sensor 64 are separated by an iron panel, that is, separated by the front panel 51, there must be a distance between the magnet 424 and the Hall sensor 64 and they cannot contact each other. The iron panel will shield the magnetic field, and only a hole (also the second through hole 514) can be opened in the iron plate to remove the shielding. However, for the sake of aesthetics and to prevent oil and dirt from entering the inside and making it difficult to clean, the hole should not be opened too large, but the magnetism of the magnet 424 should not be too strong. On the one hand, it will increase the volume and then increase the cost. In addition, when in the disassembled state, the suction is too strong and it will be sucked on the iron panel, affecting the disassembly experience. If the magnet 424 is too strong, the knob may not be in place yet, and the Hall sensor 64 will sense the signal, causing the whole machine to be powered on in advance. Therefore, the balance between the magnetism of the magnet 424 and the Hall is particularly important. In this embodiment, the knob body 40 is spirally matched with the intermediate fixing sleeve 48. When the locking knob 4 is in the collector disassembly state, the locking knob 4 will rotate counterclockwise. Driven by the thread of the intermediate fixing sleeve 48, the locking knob 4 will gradually rise during the counterclockwise rotation, increasing the distance between the magnet 424 and the iron panel, so that the collector will not be affected by the suction force of the magnet 424 when being disassembled. When locked by right rotation, the locking knob 4 will drive the magnet 424 to move downward while rotating to the right. When it is rotated to the right in place, the distance between the magnet 424 and the iron panel is also the shortest. At this time, the magnet 424 will transmit the magnetic field signal to the Hall sensor 64 through the opening of the iron panel to provide a reminder of the installation in place.

[0066] Since the iron panel has openings for normal magnetic field transmission, when the user disassembles the current collector to clean the oil stain on the overall appearance of the machine, the holes at the openings of the panel will be blocked by the grease wiped by the rag, resulting in the entry of oil stain into the openings of the panel. On the one hand, it may affect signal transmission, and on the other hand, it will reduce the user experience (the oil stain adheres to the holes). To solve this problem, in combination with the rotational movement of the locking knob 4, a linkage structure is made. A ring-shaped tooth portion 444 is correspondingly provided on the connecting column 44 of the locking member 43 of the locking knob 4, and a transmission gear 490 and a shielding plate 491 with a sector-shaped tooth 492 at the end are also provided on the rear side of the front panel 51. The transmission gear 490 and the shielding plate 491 are both rotatably arranged on the front panel 51 through corresponding pin shafts. When the locking knob 4 drives the ring-shaped tooth portion 444 to rotate, the power is transmitted to the shielding plate 491 through the transmission gear 490, and then the shielding plate 491 is driven to rotate. When the locking knob 4 is in the disassembling position (i.e., in the unlocking position), the shielding plate 491 just blocks at the second through hole 514 of the panel. At this time, when the user cleans the outer surface of the range hood, the oil stain will not be wiped into the second through hole 514. When the knob is rotated to the right to lock, the shielding plate 491 will follow the rotation of the knob and move away from the second through hole 514 of the panel, ensuring that the Hall sensor 64 can receive the magnetic induction of the magnet 424 and ensuring that the locking tongue 61 of the electromagnetic lock 6 can extend out to lock.

[0067] The air collector of this embodiment is connected to the front side plate 11 of the volute 1 by using a locking knob 4. When it is necessary to install the air collector on the front side plate 11 of the volute 1, only need to pass the limit buckle 45 of the locking knob 4 through the limit hole 111 on the front side plate 11 of the volute 1 and then rotate it by a certain angle. The limit buckle 45 can be limited at the rear side of the outer periphery of the limit hole 111 and will not protrude forward from the limit hole 111 and is in a locked state. When it is necessary to disassemble the air collector, rotate the locking knob 4 to the position where the limit rib is opposite to the limit hole 111. In this way, the limit buckle 45 can protrude forward from the limit hole 111 to achieve unlocking. The method of locking and unlocking through the locking knob 4 is more convenient for the operator to operate, the disassembly process is more labor-saving, and it is not easy to loosen or fall off due to the movement and vibration of the fan, ensuring the reliability of the connection between the air collector and the front side plate 11 of the volute 1. On this basis, a self-locking device is also provided on the volute 1. The self-locking device is inductively matched with the magnet 424 provided on the locking knob 4 through the Hall sensor 64 (that is, a non-contact locking-in-place detection device is adopted), so as to effectively identify the rotation position of the locking knob 4. When it is recognized that it rotates to the second position, the lock tongue 61 of the electromagnetic lock 6 of the self-locking device can move towards the locking position of the locking knob 4 and form a limit fit with the locking position, further ensuring the reliability of the installation of the air collector. Among them, the operator can also observe (it can be identified visually or judged by the sound of the telescopic movement of the lock tongue 61 of the electromagnetic lock 6) whether the lock tongue 61 of the electromagnetic lock 6 has cooperated with the locking position of the locking knob 4 to identify whether the knob has rotated in place, ensuring that the air collector is clearly installed in place, eliminating the anxiety and risks brought by the inability to identify whether the air collector is installed in place, and improving the user experience.

[0068] On the basis of locking through the above-mentioned locking knob 4 via the air collector and the volute, this embodiment also provides a cleaning reminder method for the range hood without increasing costs. Specifically, after the range hood is used for a period of time, oil stains will be generated on the position or components between the magnet 424 and the Hall sensor 64 (such as the inner side of the front panel 51). When the distance between the magnet 424 and the Hall sensor 64 remains unchanged, the magnetic field signal received by the Hall sensor 64 will change due to different amounts of oil stain adhesion. Therefore, the control system judges the amount of oil stain attached to the centrifugal fan according to the change amount of the magnetic field signal transmitted by the Hall sensor 64, and then issues a cleaning reminder through the alarm device. Specifically, the cleaning reminder method for the range hood includes the following steps:

[0069] When the range hood starts, the cleaning reminder program starts automatically (it can also be started by selecting through the buttons on the range hood). It judges the effective working duration of the range hood since the last cleaning. For example, if the set duration is one month, if it has not reached one month, the detection will end. If the effective working duration is reached, the control system compares the magnetic field signal U currently transmitted by the Hall sensor 64 with the magnetic field signal Us after the last cleaning to obtain the magnetic field signal change value U, and then compares U with the set magnetic field change threshold to judge the oil pollution degree of the centrifugal fan, and then issues a corresponding reminder through the alarm device. Specifically, the above magnetic field signal change value U is:

[0070]

[0071] If △U ≤ U1, it is judged as mild pollution, and a cleaning reminder is given by flashing the indicator light (the indicator light can be the ambient light of the cleaning button), and the functions of the range hood are normal and available. Then, after the centrifugal fan stops (if the centrifugal fan start operation has been performed), it is judged whether the user has carried out disassembly and cleaning. If the impeller 21 has been disassembled and cleaned, after the disassembly and cleaning are completed and installed in place, the magnetic field signal transmitted by the new Hall sensor 64 is recorded. If the disassembly and cleaning have not been carried out, the initial step is returned, and the next cleaning detection program of the range hood is awaited to start;

[0072] If U1 < △U < U2, it is judged as moderate pollution, and a cleaning reminder is given by flashing the indicator light (the indicator light can be the ambient light of the cleaning button) and making a sound. The functions of the range hood are normal and available during this startup cycle. Then, after the centrifugal fan stops (if the centrifugal fan start operation has been performed), it is judged whether the user has carried out impeller 21 disassembly and cleaning. If the disassembly and cleaning have been carried out, after the disassembly and cleaning are completed and installed in place, the magnetic field signal transmitted by the new Hall sensor 64 is recorded. If the disassembly and cleaning have not been carried out, the initial step is returned, and the next cleaning detection program of the range hood is awaited to start;

[0073] If △U≥U2, it is judged as heavy pollution, and a cleaning reminder is given by flashing the indicator light (the indicator light can be the atmosphere light of the cleaning button) and making a sound. The function of the range hood is normally available during this startup cycle, and then it is judged whether the user has disassembled and cleaned the impeller 21 after the centrifugal fan stops (if the centrifugal fan is started). If disassembled and cleaned, after the disassembly and cleaning are completed and installed in place, the magnetic field signal transmitted by the new Hall sensor 64 is recorded. If disassembled and cleaned, the function of the range hood will be unavailable after the next startup, and the user is required to force the disassembly and cleaning process or to remove the restriction on the unavailable function of the range hood through other operations. Among them, the operating steps for removing the restriction on the unavailable function of the range hood in the cleaning reminder method of the range hood are: long press the corresponding operation button on the range hood (the operation button can be a cleaning button), of course, it can also be an additional button or a touch selection button on the operation screen. If it is judged to be heavily polluted, that is, the oil between the magnet 424 and the Hall sensor 64 has affected the transmission of the magnetic field signal, the Hall sensor 64 may receive intermittent magnetic field signals. Among them, the setting that the centrifugal fan cannot be started during the next operation is to ensure that the safety protection function of the collector is normal. However, if the user forgets to clean it next time but urgently needs to cook, the centrifugal fan can be started again by long pressing the cleaning button. After the user disassembles and cleans the impeller 21, the control system will record the new magnetic field parameter data sensed by the Hall sensor 64 and store it in the system, recorded as the new Us. The above-mentioned U setting can use the preliminary laboratory data to confirm the value.

[0074] In the cleaning reminder method of the range hood, the steps for judging whether the user has disassembled and cleaned the impeller 21 are as follows: whether the Hall sensor 64 has reacquired the magnetic field signal within a set time after losing the magnetic field signal. During the process of disassembling and cleaning the impeller 21, the collector will be unlocked and rotated to be removed, and after cleaning, the collector will be installed and locked. During this process, the magnetic induction signal of the Hall sensor 64 is detected to have obvious changes. When the user is cleaning, the collector will be disassembled, and the Hall sensor 64 will lose the magnetic field signal first, and then receive the magnetic field signal after installation.

Claims

1. A range hood, comprising a centrifugal fan, the centrifugal fan comprising a volute (1) and a collector detachably mounted on the volute (1), the volute (1) comprising a front side plate (11), a rear side plate (12) and an annular wall (13) connected between the front side plate (11) and the rear side plate (12), the front side plate (11) being provided with an air inlet (110), the collector being connected to the air inlet (110) of the front side plate (11), the collector comprising an annular guide portion (31) and a connecting ring (32) extending radially outward from the guide portion (31), characterized in that: The invention also comprises a locking knob (4) which is rotatably arranged on the connecting ring (32) and is used to lock the connecting ring (32) with the front side plate (11) of the volute (1); a magnet (424) which can rotate with the locking knob (4) is also arranged on the front side of the connecting ring (32); a Hall sensor (64) is also arranged on the volute (1); the Hall sensor (64) is electrically connected to the control system of the range hood; the control system determines the amount of oil stains attached to the centrifugal fan according to the change in the magnetic field signal transmitted by the Hall sensor (64), and then issues a cleaning reminder through an alarm device.

2. The range hood according to claim 1, characterized in that: The alarm device is an alarm capable of emitting sound and / or light or a display screen capable of displaying cleaning reminder information.

3. The range hood according to claim 1, characterized in that: A mounting frame (62) is provided on the outer side of the annular wall (13) of the volute (1), and a placement cavity for placing the Hall sensor (64) is defined on the mounting frame (62).

4. The range hood according to claim 1, characterized in that: The locking knob (4) has a laterally protruding limiting convex buckle (45) on a portion located on the rear side of the connecting ring (32); a limiting hole (111) penetrating from front to back is opened on the front side plate (11); the limiting convex buckle (45) of the locking knob (4) can pass through the limiting hole (111) and can be rotated and switched between a first position relative to the limiting hole (111) and a second position offset from the limiting hole (111); when the locking knob (4) is located at the first position, in the rotation direction of the locking knob (4), the magnet (424) on the locking knob (4) is away from the Hall sensor (64); when the locking knob (4) is located at the second position, in the rotation direction of the knob, the magnet (424) on the locking knob (4) is close to the Hall sensor (64).

5. The range hood according to claim 4, characterized in that: The connecting ring (32) is provided with an axial hole (3210), and the locking knob (4) includes a knob body (40), a locking rod (46) and a locking member (43). The knob body (40) and the locking member (43) are respectively located at the front and rear sides of the connecting ring (32), and are connected by a locking rod (46) inserted through the axial hole (3210). The locking member (43) includes a connecting column (44) and a limiting protrusion (45) extending from the connecting column (44) to the side. The locking rod (46) and the knob body (40) are detachably connected, and the first end of the locking rod (46) and the knob body (40) can be limited in the axial and circumferential directions of the locking rod (46). The magnet (424) is arranged on the knob body.

6. The range hood according to claim 5, characterized in that: The connecting column (44) has an axially opened movable channel (440), the second end of the locking rod (46) is slidably arranged in the movable channel (440), and the second end of the locking rod (46) and the inner wall of the movable channel (440) are limited in the circumferential direction by keyway cooperation, the first end of the locking rod (46) has a limiting pin (461) protruding radially outward, the knob body (40) defines a locking chamber (420) inside, and a locking member (420) is provided on the side facing the locking member (43) so that the first end of the locking rod (46) and its limiting pin (461) can extend into the locking chamber (420). 0), an elastic member (47) is further provided in the movable channel (440), the elastic member (47) acts on the locking rod (46) and makes the locking rod (46) always have a tendency to move along its axial direction toward a side away from the knob body (40), the inner wall of the locking chamber (420) is provided with a limiting groove (421) on a side adjacent to the first mounting opening (422), the limiting pin (461) of the locking rod (46) passes through the first mounting opening (422) and enters the locking chamber (420), and after rotating a certain angle, it can be snapped into the limiting groove (421) under the action of the elastic member (47).

7. The range hood according to claim 5, characterized in that: The knob body (40) comprises a limiting plate (42) located on the front side of the connecting ring (32) and a knob operating portion (41) protruding on the front side of the limiting plate (42); when the locking knob (4) is in the second position, a portion of the limiting plate (42) is exposed outside the outer peripheral edge of the connecting ring (32), and the magnet (424) is provided on the inner side of the portion of the limiting plate (42) that exposes the outer peripheral edge of the connecting ring (32).

8. The range hood according to claim 6, characterized in that: The knob body (40) is provided with a connecting hole (423) on a side facing the locking member (43); a first mounting opening (422) penetrating into the locking chamber (420) is provided on a bottom wall of the connecting hole (423); a fixing sleeve (48) is provided on a side of the connecting ring (32) facing the knob body (40) at the position of the shaft hole (3210); the locking rod (46) passes through the fixing sleeve (48) and is connected to the knob body (40); the fixing sleeve (48) extends into the connecting hole (423), and the outer peripheral wall of the fixing sleeve (48) is connected to the inner peripheral wall of the connecting channel (423) by a threaded connection, so that the knob body (40) can be axially closer to or farther away from the connecting ring (32) when rotating forward and reversely. When the locking knob (4) is located in the above-mentioned first position, the locking knob (4) is axially away from the connecting ring (32), and when the locking knob (4) is located in the above-mentioned second position, the locking knob (4) is axially close to the connecting ring (32).

9. The range hood according to any one of claims 4 to 8, characterized in that: The invention also comprises a casing (5), wherein the centrifugal fan is arranged in the casing (5), and the casing (5) comprises a front panel (51), wherein the front panel (51) has a third mounting opening (511) opposite to the air inlet (110) of the volute (1), wherein the connecting ring (32) of the collector is abutted against the front side of the peripheral edge of the third mounting opening (511), and a first through hole (512) is provided on the peripheral edge of the third mounting opening (511), which is opposite to the limiting hole (111) and can allow the rear end of the locking knob (4) and the limiting convex buckle (45) provided on the rear end thereof to pass through, and a second through hole (514) is also provided on the peripheral edge of the third mounting opening (511), and the second through hole (514) is opposite to the magnet (424) on the locking knob (4) in the second position state.

10. The range hood according to claim 9, characterized in that: It also includes a baffle plate (491) that is rotatably arranged on the inner side of the front panel (51), and the baffle plate (491) and the locking knob (4) are linked via a transmission assembly, thereby driving the baffle plate (491) to rotate during the rotation of the locking knob (4); when the locking knob (4) is located at the first position, the baffle plate (491) closes the second through hole (514); when the locking knob (4) is located at the second position, the baffle plate (491) opens the second through hole (514).

11. The range hood according to any one of claims 4 to 8, characterized in that: The volute (1) is also provided with a self-locking device, which includes an electromagnetic lock (6), the electromagnetic lock (6) includes a locking tongue (61), and the locking knob (4) has a locking position on a side facing the electromagnetic lock (6). The electromagnetic lock (6) is electrically connected to a control system of the range hood, and the Hall sensor (64) identifies the rotational position of the locking knob (4) through inductive cooperation with the magnet (424), so that when the locking knob (4) is located in the second position, the control system controls the locking tongue (61) of the electromagnetic lock (6) to move toward the locking position of the locking knob (4) to form a limit fit.

12. A cleaning reminder method for a range hood, the range hood being the range hood according to any one of claims 1 to 11, characterized in that The following steps are involved: The cleaning detection program of the range hood is started, and the control system compares the magnetic field signal U currently transmitted by the Hall sensor (64) with the magnetic field signal Us after the last cleaning to obtain a magnetic field signal change value U, and then compares U with a set magnetic field change threshold to determine the degree of oil pollution of the centrifugal fan, and then issues a corresponding reminder through the alarm device.

13. The range hood cleaning reminder method according to claim 12, characterized in that The method comprises the following steps: it also comprises judging whether the user has carried out the step of disassembling and cleaning the impeller (21) during the current startup cycle; if so, after the disassembly and cleaning are completed and the impeller is installed in place, recording the magnetic field signal newly transmitted by the Hall sensor (64) as the magnetic field signal Us for comparison next time; if not, returning to the initial step to wait for the next cleaning and detection program of the range hood to be started, or a corresponding reminder is still issued through the alarm device after the range hood is started next time.

14. The range hood cleaning reminder method according to claim 12, characterized in that The following steps are involved: The change value U of the magnetic field signal is: If △U≤U1, it is judged as light pollution, and a cleaning reminder is given by flashing the indicator light, while the functions of the range hood are normally available. Then it is judged whether the user has disassembled and cleaned the impeller (21). If the impeller (21) is disassembled and cleaned, after the disassembly and cleaning are completed and installed in place, the magnetic field signal transmitted by the new Hall sensor (64) is recorded. If the impeller (21) is not disassembled and cleaned, the initial step is returned to wait for the next cleaning detection program of the range hood to be started; If U1 < △U < U2, it is judged as moderate pollution, and a cleaning reminder is given by flashing the indicator light and emitting a sound. The functions of the range hood are normally available during this startup cycle. Then it is judged whether the user has disassembled and cleaned the impeller (21). If it has been disassembled and cleaned, after the disassembly and cleaning are completed and installed in place, the magnetic field signal transmitted by the new Hall sensor (64) is recorded. If it has not been disassembled and cleaned, the initial step is returned to wait for the next cleaning detection program of the range hood to start; If △U≥U2, it is judged as heavy pollution, and a cleaning reminder is given by flashing the indicator light and emitting a sound. The functions of the range hood are normally available during this startup cycle. Then it is judged whether the user has disassembled and cleaned the impeller (21). If disassembly and cleaning are performed, after the disassembly and cleaning are completed and installed in place, the magnetic field signal transmitted by the new Hall sensor (64) is recorded. If disassembly and cleaning are not performed, the function of the range hood is unavailable after the next startup, and the user needs to force the disassembly and cleaning process or remove the restriction on the unavailability of the range hood function through other operations.

15. The range hood cleaning reminder method according to claim 14, characterized in that: The steps for judging whether the user has performed the disassembly and cleaning process of the impeller (21) are as follows: whether the Hall sensor (64) has acquired the magnetic field signal again within a set time after losing the magnetic field signal.

16. The range hood cleaning reminder method according to claim 14, characterized in that: The operation steps to remove the restriction on the unavailability of the range hood function are: long press the corresponding operation button on the range hood.

17. The cleaning reminder method for a range hood according to any one of claims 14 to 16, characterized in that The following steps are involved: After the range hood is turned on, it automatically enters the cleaning and detection program of the range hood.

18. The cleaning reminder method for a range hood according to any one of claims 14 to 16, characterized in that The method comprises the following steps: after the range hood is turned on, the effective working time of the range hood from the last disassembly and cleaning operation is determined, and after the effective working time reaches the set time, the cleaning detection program of the range hood is entered; if the effective working time reaches the set time, the cleaning detection program of the range hood is not entered.

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