Electric pressure cooker and display control method thereof

Abstract

The present application relates to the technical field of electric pressure cookers, and discloses an electric pressure cooker and a display control method thereof, which are used to solve the problem that the animation rhythm of the existing electric pressure cooker panel is out of sync with the real pressure change process in the pot, and the animation start and stop is out of position with the seating time of the float valve. The electric pressure cooker comprises a pot body, a pot cover, an inner container, a heat dissipation fan, a float valve, a pressure sensor, a float valve position detection piece, a display screen and a controller. The controller collects the pressure value of the pressure sensor at a preset sampling period and calculates the pressure change rate; in the cooking pressure rising stage, the display screen is driven to display a first dynamic pattern representing the steam rising state; in the air cooling pressure reducing stage, the heat dissipation fan is started, and the display screen is driven to display a second dynamic pattern representing the fan rotating state; after receiving the float valve seating signal, the second dynamic pattern is switched to an openable cover identifier, and the heat dissipation fan is controlled to stop running with a delay. The present application maps the pressure change rate in real time to the dynamic pattern step frequency, so that the panel animation rhythm is mapped to the pressure change in the pot; and the float valve seating signal is used as a unified trigger source to realize the time sequence hard synchronization of the display final state, mechanical unlocking and air cooling stop.

Description

Technical Field

[0001] This application relates to the field of electric pressure cooker technology, and in particular to an electric pressure cooker with synchronous dynamic display of pressure increase and decrease, and a display control method thereof. Background Technology

[0002] Electric pressure cookers increase the boiling point of the contents by sealing and pressurizing. After cooking, residual pressure remains in the pot. A float valve on the lid keeps the lid raised and mechanically locked until the pressure drops to a safe level. To shorten the waiting time before opening the lid, existing technologies use a cooling fan inside the pot to blow air onto the outer wall of the inner pot for air cooling and pressure reduction. Chinese patent CN108143261A discloses an electric pressure cooker with a cooling fan and a pressure-reducing valve; this solution uses the cooling fan to accelerate cooling and achieve rapid pressure reduction. Meanwhile, existing products generally display "Pressure increasing" or "Pressure decreasing" on the panel or a looping animation to indicate the current cooking stage.

[0003] However, in the above panel prompt scheme, the rhythm of the dynamic pattern is preset to a fixed value by the program and is not related to the actual pressure change process inside the pot. The air-cooled pressure reduction follows a physical law of being fast at first and then slowing down, while the panel animation always cycles at a fixed rhythm. Users cannot judge the current pressure reduction rate and the remaining waiting time through the animation. In addition, the start and end times of the animation are determined by the software state machine, and there is no synchronization relationship between it and the float valve setting, which is the mechanical action that truly determines whether the pot lid can be opened. This results in timing misalignment problems such as "the animation is still jumping while the pot lid can be opened" or "the animation has stopped while the pot lid still cannot be turned". Summary of the Invention

[0004] The purpose of this invention is to provide an electric pressure cooker and its display control method to solve the technical problems existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides an electric pressure cooker, including a pot body, a lid, an inner pot, a cooling fan, and a float valve; it also includes: a pressure sensor, connected to the inner cavity of the pot body, for collecting the pressure value inside the pot; a float valve position detection device, disposed at the float valve and signal-connected to the controller, for outputting a settling signal to the controller when the float valve is seated; a display screen, electrically connected to the controller; and a controller, electrically connected to the pressure sensor and the cooling fan. The controller is configured to periodically collect the pressure value from the pressure sensor according to a preset sampling period; during the cooking pressurization phase, the controller drives the display screen to display a first dynamic pattern, which represents the steam rising state so that the user can observe that the cooking pressure in the inner pot is in the pressurization phase; during the air-cooling depressurization phase, the cooling fan is activated, and the controller drives the display screen to display a second dynamic pattern, which represents the fan rotation state so that the user can observe that the cooking pressure in the inner pot is in the air-cooling depressurization phase; after receiving the settling signal, the controller switches the second dynamic pattern to an openable lid indicator and controls the cooling fan to stop operating after a delay period. By differentially calculating the periodic sampling values ​​of the pressure sensor, the real-time pressure change rate is obtained, and the absolute value of the pressure change rate is mapped to the flow step frequency of the first dynamic pattern, so that the visual rhythm of the panel animation becomes the real-time encoding carrier of the speed of pressure change in the pot; at the same time, the landing signal of the float valve position detection component is used as the unified trigger source for the display final state switching and the fan stop, realizing the hard synchronization of the display final state, mechanical unlocking and air cooling stop in time sequence.

[0006] Furthermore, the flow step frequency of the first dynamic pattern has a linear proportional relationship with the absolute value of the pressure change rate. This linear proportional mapping is simple to implement, and the step frequency responds proportionally to the increase or decrease of the pressure change rate, facilitating real-time calculation and driving by the controller.

[0007] Preferably, the controller is further configured to limit the flow step frequency of the first dynamic pattern, restricting the flow step frequency between a preset minimum step frequency and a preset maximum step frequency. The limiting process ensures that the animation does not completely stop when the pressure change rate approaches zero, and that the animation does not lose readability due to excessive refresh when the pressure change rate is too large, thus maintaining visual continuity of the animation across the entire pressure change rate range.

[0008] Specifically, the display screen is a dot matrix display screen, and the first dynamic pattern and the second dynamic pattern are driven by the dot matrix display screen through line-by-line refresh. The dot matrix display screen drives the pattern units to light up and turn off step by step through line-by-line refresh, which can intuitively present directional flowing dynamic effects, and the step frequency adjustment only requires changing the refresh time interval parameter, making the control logic simple.

[0009] Furthermore, the first dynamic pattern is a steam-rising pattern, comprising several pattern units that light up progressively from bottom to top. The steam-rising pattern visually corresponds to the physical phenomenon of steam accumulating upwards inside the boiler during the pressurization process, helping users intuitively understand that they are currently in the pressurization stage.

[0010] Furthermore, the second dynamic pattern is a cooling fan rotating pattern, comprising several pattern units that light up sequentially in a clockwise direction. The cooling fan rotating pattern visually corresponds to the actual physical state of the cooling fan rotating during the air-cooled voltage reduction phase, helping users intuitively understand that they are currently in the air-cooled voltage reduction phase.

[0011] In some embodiments, the float valve position detection element is a microswitch. The trigger of the microswitch cooperates with the lower end of the float valve core. When the float valve is seated, the valve core presses down on the trigger, the microswitch closes, and outputs the seating signal to the controller. The microswitch has a simple structure and rapid response. The contact detection method of the valve core pressing down on the trigger has high reliability, and the timing delay between the seating signal and the mechanical action of the float valve is minimal.

[0012] In some embodiments, the float valve position detection element is an inductive displacement sensor. A magnetic conductor is provided at the upper end of the float valve core. When the float valve is seated, the magnetic conductor moves out of the sensing area of ​​the inductive displacement sensor, and the inductive displacement sensor outputs a level transition signal as the seating signal. The inductive displacement sensor is a non-contact detection method, eliminating mechanical contact wear issues and making it suitable for product designs with high requirements for contact lifespan and sealing performance.

[0013] Preferably, the openable lid indicator includes at least one of text indicating that the lid can be opened and a static graphic indicating the open state of the lid. The openable lid indicator clearly informs the user that the lid can be safely opened with static text or graphics, forming a clear visual distinction from the dynamic pattern during the depressurization phase, thus avoiding misjudgment by the user regarding when to open the lid.

[0014] As a preferred embodiment, the controller is further configured to: during the air-cooling depressurization phase, when the absolute value of the pressure change rate is lower than a preset threshold, reduce the flow frequency of the first dynamic pattern to a preset minimum frequency and maintain it, while simultaneously driving the display screen to overlay a prompt message indicating that the lid is about to be opened. This transition prompt is triggered based on the real-time pressure change rate, and its accuracy is not affected by factors such as the amount of food, the amount of soup, or the ambient temperature, providing users with a gradual two-stage lid-opening guidance.

[0015] This invention also provides a display control method for an electric pressure cooker, comprising the following steps: periodically collecting pressure values ​​inside the cooker according to a preset sampling period, and calculating the pressure change rate within adjacent sampling periods; during the pressure-increasing phase, driving the display screen to display a first dynamic pattern, wherein the flow direction of the first dynamic pattern is from bottom to top, and the flow step frequency of the first dynamic pattern is positively correlated with the absolute value of the pressure change rate; during the air-cooling pressure-reducing phase, starting the cooling fan and driving the display screen to display a second dynamic pattern, wherein the second dynamic pattern is associated with the rotation state of the cooling fan; detecting whether the float valve is seated; when the seated float valve is detected, switching the second dynamic pattern to an openable lid indicator, and controlling the cooling fan to stop running after a delay period. The above method, by performing real-time differential calculation on the pressure sensor sampling values ​​and mapping the results to the display step frequency of the first dynamic pattern, ensures that the animation rhythm during the pressure-increasing phase corresponds in real time to the actual pressure-increasing process inside the cooker, and uses the float valve seated signal as the trigger condition for the final state of the method, guaranteeing the timing consistency between the method execution result and the mechanical unlocking action.

[0016] Furthermore, the pressure change rate is calculated by dividing the difference between the nth sampled pressure value and the (n-1th)th sampled pressure value by the preset sampling period. This first-order differential calculation method has low computational complexity and can complete real-time calculation within each sampling period of the controller, meeting the timeliness requirements of real-time step frequency mapping.

[0017] Preferably, after determining the flow step frequency of the first dynamic pattern during the pressurization stage based on the pressure change rate, the flow step frequency is limited to between a preset minimum step frequency and a preset maximum step frequency. This step frequency limiting process ensures that the first dynamic pattern maintains a normal visual presentation even under boundary conditions where the pressure change rate is extremely small or extremely large.

[0018] Furthermore, during the air-cooling depressurization stage, when the absolute value of the pressure change rate is lower than a preset threshold, the flow frequency of the first dynamic pattern is reduced to a preset minimum frequency and maintained, while the display screen is driven to overlay a prompt message indicating that the lid is about to be opened. This step provides the user with advance notice before the float valve is seated, reducing the user's uncertainty while waiting, and together with the subsequent step of confirming the lid opening status by triggering the float valve seat, constitutes a complete lid opening guidance process.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. The controller collects the pressure value of the pressure sensor in real time according to the preset sampling period and calculates the pressure change rate within adjacent sampling periods. The absolute value of the pressure change rate is mapped into the flow step frequency of the dynamic pattern in real time, so that the visual rhythm of the panel animation becomes the real-time encoding carrier of the speed of pressure change in the pot. This overcomes the defects of the existing technology where the animation step frequency is a fixed value preset by the program and is completely disconnected from the actual pressure change process in the pot. Users can intuitively perceive the current rate of pressure increase or decrease simply by the change in the speed of the animation rhythm, without having to repeatedly try to tighten the pot lid or rely on inaccurate remaining time estimation.

[0020] 2. By displaying a first dynamic pattern with the flow direction from bottom to top during the boost phase and a second dynamic pattern related to the rotation state of the cooling fan during the air-cooling depressurization phase, the physical process of air-cooling depressurization is presented intuitively in the form of patterns. This allows users to distinguish the current cooking stage by the direction and shape of the patterns without reading any text prompts. The intuitive correspondence between the pattern shape and the fan operation status reduces the cognitive load on users.

[0021] 3. By setting a float valve position detection device at the float valve, the sitting signal output when the float valve sits down is used as a unified trigger source to switch the second dynamic pattern to the openable lid indicator and trigger the cooling fan to stop after a delay. This achieves hard synchronization of the display final state, mechanical unlocking and air cooling stop in terms of timing, fundamentally eliminating the problem of misalignment between the animation start and end determined by the software state machine and the timing of the float valve's mechanical action in the existing technology. This ensures that the time when the openable lid indicator appears strictly corresponds to the time when the pot lid can actually be safely opened. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of an electric pressure cooker provided in one embodiment of this application.

[0023] Figure 2 This is a block diagram of the architecture of an electric pressure cooker control system provided in one embodiment of this application.

[0024] Figure 3 This is a flowchart illustrating an embodiment of the electric pressure cooker display control method provided in this application. Detailed Implementation

[0025] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the following embodiments are used to illustrate the technical solutions of the present application, and are not intended to limit the scope of protection of the present application.

[0026] This application provides an electric pressure cooker and its display control method. The core improvement lies in the following: the controller periodically collects the pressure value of the pressure sensor inside the cooker according to a preset sampling period, performs differential calculation on adjacent sampling values ​​to obtain the real-time pressure change rate, and maps the absolute value of the pressure change rate to the flow step frequency of the dynamic pattern on the display screen; at the same time, a float valve position detection device is set at the float valve, and the sitting signal output when the float valve sits down is used as a unified trigger source to switch the dynamic pattern to the openable lid indicator and trigger the cooling fan to stop after a delay. This solves the technical problems in the prior art where the rhythm of the panel animation is out of sync with the actual pressure change process inside the cooker, and the start and end of the animation are misaligned with the timing of the mechanical action of the float valve.

[0027] Example 1 Reference Figure 1 In one embodiment, the electric pressure cooker 100 includes a pot body 10, a lid 20, an inner pot 30, a heating plate 40, a cooling fan 50, a pressure sensor 70, a float valve 60, a float valve position detection element 80, a display screen 90, and a controller 110. The inner pot 30 is housed inside the pot body 10. The heating plate 40 is located at the bottom of the inner pot 30 and abuts against the bottom wall of the inner pot 30 for heating the inner pot 30. The lid 20 is fastened to the top of the pot body 10 and forms a sealed cavity with the pot body 10 through a sealing ring 21. The float valve 60 is installed on the lid 20. When the pressure inside the pot exceeds a safety threshold, the pressure inside the pot pushes up the valve core of the float valve 60. When the valve core is in the pushed-up state, the lid 20 is mechanically locked, preventing the lid 20 from being opened.

[0028] A cooling fan 50 is located between the inner wall of the pot body 10 and the outer wall of the inner liner 30, with its outlet facing the outer wall of the inner liner 30. During the air-cooling and pressure-reducing phase, it is driven by the controller 110 to deliver air to the outer wall of the inner liner 30 to accelerate the cooling and pressure reduction inside the pot. A pressure sensor 70 is fixed inside a pressure-conducting pipe on the pot lid, which communicates with the inner cavity of the pot body 10. It is used to detect the pressure value inside the pot in real time and output the pressure signal to the controller 110. In another embodiment, the pressure sensor can be installed below the inner liner and fixed to the outer pot, similar to the pressure sensors commonly found in the prior art that are actuated by the displacement of the heating plate. A display screen 90 is located on the control panel on the outer wall of the pot body 10 and is electrically connected to the controller 110. It is used to display dynamic patterns or static indicators. The controller 110 is electrically connected to the pressure sensor 70, the cooling fan 50, the display screen 90, and the float valve position detection element 80, and is responsible for data acquisition, calculation, display driving, and actuator control.

[0029] Combination Figure 2The controller 110 includes a pressure sampling module 111, a pressure change rate calculation module 112, a step frequency mapping and limiting processing module 113, a display driving module 114, a fan control module 115, and a seating signal processing module 116. The controller 110 periodically collects the pressure values ​​output by the pressure sensor 70 according to a preset sampling period T. Let the pressure value obtained from the nth sampling be Pn, and the pressure value obtained from the (n-1)th sampling be Pn-1. Then, the pressure change rate calculation module 112 calculates the current pressure change rate ΔP / Δt by dividing the difference between Pn and Pn-1 by the preset sampling period T, i.e., ΔP / Δt = (Pn - Pn-1) / T. This first-order difference calculation method has a small computational load and can complete real-time calculation within each sampling period.

[0030] The controller determines the flow rate f of the current dynamic pattern based on the absolute value of the pressure change rate |ΔP / Δt|. The flow rate f is positively correlated with |ΔP / Δt|; that is, the faster the pressure changes inside the pot, the higher the flow rate of the dynamic pattern, and vice versa. Thus, the visual rhythm of the panel animation becomes a real-time encoding of the rate of pressure change inside the pot, allowing users to intuitively perceive the current rate of pressure increase or decrease simply by observing the changes in the animation's rhythm. In another implementation, the flow rate of the dynamic pattern can remain constant.

[0031] During the pressurization phase, the controller detects a continuous increase in pressure inside the boiler and drives the display screen to show the first dynamic pattern. The flow direction of the first dynamic pattern is from bottom to top, with pattern units lighting up sequentially from the bottom of the display screen upwards, simulating the physical phenomenon of steam accumulating upwards inside the boiler. The controller adjusts the flow frequency of the first dynamic pattern in real time according to the absolute value of the current pressure change rate; the faster the pressurization rate, the faster the pattern flows upwards, and vice versa. The bottom-to-top flow direction of the pattern is consistent with the physical direction of steam accumulation during the pressurization process, helping users intuitively distinguish that they are currently in the pressurization phase.

[0032] After cooking, the pot enters the air-cooling decompression stage. The controller activates the cooling fan, which blows air onto the outer wall of the inner pot to accelerate cooling. Simultaneously, the controller switches the display to a second dynamic pattern. This second dynamic pattern depicts a rotating cooling fan, with the pattern units lighting up sequentially in a clockwise direction, simulating the continuous rotation and airflow of the cooling fan, visually demonstrating its operation during the air-cooling decompression stage.

[0033] A float valve position detection element 80 is located at the float valve 60 and is signal-connected to the controller 110. When the pressure inside the pot drops to a safe value, the valve core of the float valve 60 settles under its own weight. The float valve position detection element 80 detects the settling state of the valve core and outputs a settling signal to the controller 110. Upon receiving the settling signal, the controller 110 immediately stops refreshing the second dynamic pattern, switches the display screen 90 to the openable lid indicator, and simultaneously starts a delay timer. After the delay ends, it controls the cooling fan 50 to stop running. Thus, the final state switching of the display, the mechanical unlocking of the float valve, and the stopping of the cooling fan are achieved in hard synchronization in terms of timing, completely eliminating the misalignment problem between the start and end of the animation and the timing of the mechanical action of the float valve in the prior art.

[0034] In some implementations, the step frequency f is linearly proportional to the absolute value of the pressure change rate |ΔP / Δt|, i.e., f = k × |ΔP / Δt|, where k is a preset proportionality coefficient stored in the controller. This linear proportional mapping is simple to implement, and the step frequency responds proportionally to the increase or decrease in the pressure change rate, facilitating real-time calculation and actuation by the controller in each sampling period.

[0035] In some implementations, the controller limits the flow step frequency f of the first dynamic pattern during the pressure boosting phase, restricting the step frequency to between a preset minimum step frequency fmin and a preset maximum step frequency fmax. When the calculated step frequency is lower than fmin, the controller forcibly sets the step frequency to fmin; when the calculated step frequency is higher than fmax, the controller forcibly sets the step frequency to fmax. This limiting process ensures that the first dynamic pattern does not become completely static due to an excessively low step frequency when the pressure change rate approaches zero, and that the first dynamic pattern does not lose visual readability due to excessively rapid refresh when the pressure change rate is too high, thus maintaining visual continuity of the first dynamic pattern across the entire pressure change rate range.

[0036] In some implementations, the display screen is a dot matrix display screen, and the first and second dynamic patterns are driven by the dot matrix display screen to refresh line by line. The dot matrix display screen is composed of several pixel dot matrices. The controller determines the time interval between two adjacent line refreshes according to the current step frequency f, and drives the dot matrix display screen to light up or turn off the pattern units line by line to achieve a directional flowing animation effect. Step frequency adjustment only requires changing the line refresh time interval parameter, the control logic is simple, and it is suitable for implementation on low-cost microcontrollers.

[0037] In some embodiments, the first dynamic pattern is a steam-rising pattern, comprising several pattern units that light up sequentially from bottom to top. Each pattern unit is activated sequentially from bottom to top on the dot matrix display screen, creating a visual effect of steam continuously rising upwards. The second dynamic pattern is a cooling fan-rotating pattern, comprising several pattern units that light up sequentially in a clockwise direction. Each pattern unit is activated sequentially in a clockwise direction on the dot matrix display screen, creating a visual effect of a cooling fan continuously rotating.

[0038] In some implementations, the openable lid indicator includes at least one of a textual indication of openability and a static graphic indicating the lid's open status. The openable lid indicator clearly informs the user, with static text or graphics, that the lid is safe to open, creating a distinct visual contrast with the continuously flowing second dynamic pattern during the depressurization phase, enabling the user to accurately determine when to open the lid.

[0039] Example 2 In one embodiment, the float valve position detection element is a microswitch. The microswitch is fixed to the float valve seat inside the pot lid, with the trigger of the microswitch facing the lower end of the float valve core. When the pressure inside the pot pushes the float valve core up, the lower end of the valve core disengages from the trigger, and the microswitch is in the open state. When the pressure inside the pot drops back to a safe value, the float valve core returns to its seat under its own weight, the lower end of the valve core presses down on the trigger, the microswitch closes, and outputs a seat signal to the controller.

[0040] Microswitches have a simple structure and rapid response, and the contact-type detection method of the valve core pressing trigger is highly reliable. Due to the extremely short travel of the microswitch, the timing delay between the seat signal and the mechanical action of the float valve core reaching the seat position is minimal, ensuring that the controller's response to the seat signal is highly consistent with the float valve's mechanical unlocking time.

[0041] Example 3 In another embodiment, the float valve position detection element is an inductive displacement sensor. A magnetic conductor is fixed to the upper end of the float valve core, and a hollow inductor coil is installed at a corresponding position inside the pot lid. The hollow inductor coil is electrically connected to the detection circuit, which is in turn electrically connected to the controller. When the pressure inside the pot pushes the float valve core up, the magnetic conductor inserts into the central region of the hollow inductor coil, increasing the inductance of the coil, and the detection circuit outputs a high-level signal. When the pressure inside the pot drops and the float valve core settles, the magnetic conductor moves out of the sensing region of the hollow inductor coil, decreasing the inductance, and the detection circuit outputs a level transition signal. This level transition signal is used as a settling signal input to the controller.

[0042] Inductive displacement sensors employ a non-contact detection method, eliminating mechanical contacts between the magnetic conductor and the hollow inductor coil, thus avoiding contact wear issues. This makes them suitable for product designs with high requirements for contact lifespan and sealing performance. Both the float valve position detection device implemented using the aforementioned inductive displacement sensor and the float valve position detection device implemented using a microswitch fall within the scope of protection of the "float valve position detection device" in the independent claim, and both can achieve the core function of outputting a seating signal to the controller when the float valve is seated.

[0043] Example 4 Combination Figure 3In one embodiment, the display control method for an electric pressure cooker includes the following steps.

[0044] Step S1: The controller periodically collects the pressure values ​​from the pressure sensor inside the pot according to a preset sampling period T, and calculates the pressure change rate within adjacent sampling periods. Specifically, the pressure change rate ΔP / Δt = (Pn - Pn-1) / T is obtained by dividing the difference between the nth sampling pressure value Pn and the (n-1)th sampling pressure value Pn-1 by the preset sampling period T.

[0045] In step S2, when the controller determines that the cooking pressure-increasing stage is underway, it drives the display screen to show the first dynamic pattern. The flow direction of the first dynamic pattern is from bottom to top, and the flow step frequency is positively correlated with the absolute value of the pressure change rate. In each sampling cycle, the controller updates the flow step frequency of the first dynamic pattern in real time based on the latest calculated absolute value of the pressure change rate, so that the animation rhythm corresponds to the pressure increase rate in the pot in real time.

[0046] Step S3: After cooking is completed, the controller determines that the air-cooling decompression stage has been entered, starts the cooling fan, and drives the display screen to switch to the second dynamic pattern. The second dynamic pattern is associated with the rotation state of the cooling fan. The pattern units light up one by one in a clockwise direction, intuitively showing the operating status of the cooling fan.

[0047] Step S4: The controller continuously monitors the output signal of the float valve position detection element to determine whether the float valve is seated.

[0048] In step S5, when the controller detects a seat signal from the float valve position detection element, it determines that the float valve has seated and the lid can be safely opened. The controller immediately switches the second dynamic pattern to the openable lid indicator and starts a delay timer. After the delay, the cooling fan stops running. The appearance of the openable lid indicator strictly corresponds to the mechanical unlocking time of the float valve, ensuring the timing consistency between the final displayed state and the actual openable lid state.

[0049] In some implementations, in step S2, after the controller determines the flow step frequency of the first dynamic pattern based on the absolute value of the pressure change rate, it performs amplitude limiting processing on the step frequency, limiting the flow step frequency between a preset minimum step frequency fmin and a preset maximum step frequency fmax, so as to ensure that the first dynamic pattern can maintain a normal visual presentation effect throughout the entire pressure change rate range.

[0050] In some implementations, during step S3, when the controller detects that the absolute value of the pressure change rate is lower than a preset threshold, it reduces the flow frequency of the first dynamic pattern to a preset minimum flow frequency fmin and maintains it, while simultaneously driving the display screen to overlay a prompt message indicating that the lid is about to be opened. This transition prompt is triggered based on the real-time pressure change rate, and its accuracy is not affected by factors such as the amount of food, the amount of soup, or the ambient temperature. Together with the subsequent step of the float valve settling to trigger the lid-opening indicator confirmation, it constitutes a complete two-stage lid-opening guidance process.

[0051] Understandably, without changing the core control mechanism mentioned above, the display screen is not limited to a dot matrix display screen; it can also be an LCD display screen or a segment display screen, as long as it can drive directional dynamic patterns and support flow step frequency adjustment.

[0052] It is understandable that the calculation of the pressure change rate is not limited to the first-order difference between two adjacent samples. A multi-point moving average followed by difference can also be used to filter out sampling noise, as long as a real-time change rate value reflecting the speed of pressure change inside the pot can be obtained.

[0053] It is understood that the delay time of the cooling fan can be adjusted according to the product model and the heat capacity of the inner liner. In one specific embodiment, the delay period can be set to 10 seconds to 60 seconds, and the specific value can be determined by those skilled in the art based on the heat capacity of the inner liner and the heat dissipation performance of the product, and is not limited here.

[0054] Where there is no conflict, the technical features in the foregoing embodiments can be combined with each other.

Claims

1. An electric pressure cooker, comprising a pot body, a lid, an inner pot, a cooling fan, and a float valve; characterized in that, Also includes: Pressure sensor used to collect pressure values ​​inside the pot; A float valve position detection device is provided at the float valve and is used to output a seating signal when the float valve is seated. The display screen is electrically connected to the controller; as well as The controller is electrically connected to the pressure sensor, electrically connected to the cooling fan, and signal-connected to the float valve position detection element. The controller is configured to periodically collect the pressure value of the pressure sensor according to a preset sampling period. During the cooking pressurization stage, the controller drives the display screen to display a first dynamic pattern, which represents the steam rising state so that the user can observe that the inner pot is in the cooking pressurization stage. During the air-cooling depressurization stage, the cooling fan is activated, and the controller drives the display screen to display a second dynamic pattern, which represents the fan rotation state so that the user can observe that the inner pot is in the air-cooling depressurization stage. After receiving the seating signal, the controller switches the second dynamic pattern to an openable lid indicator and controls the cooling fan to stop running after a delay period.

2. The electric pressure cooker according to claim 1, characterized in that, The first dynamic pattern is a steam rising from bottom to top, and the second dynamic pattern is a fan rotating in a clockwise direction.

3. The electric pressure cooker according to claim 2, characterized in that, The controller calculates the pressure change rate within adjacent sampling periods and controls the flow step frequency of the first dynamic pattern to be positively correlated with the absolute value of the pressure change rate.

4. The electric pressure cooker according to claim 3, characterized in that, The flow step frequency of the first dynamic pattern is linearly proportional to the absolute value of the pressure change rate.

5. The electric pressure cooker according to claim 3 or 4, characterized in that, The controller is also configured to limit the flow step frequency of the first dynamic pattern, limiting the flow step frequency between a preset minimum step frequency and a preset maximum step frequency.

6. The electric pressure cooker according to claim 1, characterized in that, The display screen is a dot matrix display screen, and the first dynamic pattern and the second dynamic pattern are implemented by the dot matrix display screen through line-by-line refresh.

7. The electric pressure cooker according to claim 6, characterized in that, The first dynamic pattern is a steam rising pattern, which includes several pattern units that are lit up from bottom to top.

8. The electric pressure cooker according to claim 6, characterized in that, The second dynamic pattern is a cooling fan rotating pattern, which includes several pattern units that light up sequentially in a clockwise direction.

9. The electric pressure cooker according to claim 1, characterized in that, The float valve position detection device is a micro switch. The trigger of the micro switch cooperates with the lower end of the valve core of the float valve. When the float valve is seated, the valve core presses down on the trigger, the micro switch closes and outputs the seating signal to the controller.

10. The electric pressure cooker according to claim 1, characterized in that, The float valve position detection device is an inductive displacement sensor. The upper end of the float valve core is provided with a magnetic conductor. When the float valve is seated, the magnetic conductor moves out of the sensing area of ​​the inductive displacement sensor. The inductive displacement sensor outputs a level transition signal as the seating signal.

11. The electric pressure cooker according to claim 1, characterized in that, The openable lid marking includes at least one of the following: a text marking indicating that the lid can be opened and a static graphic indicating that the lid is open.

12. A display control method for an electric pressure cooker, characterized in that, The method includes the following steps: Step S1: Periodically collect the pressure value inside the pot according to the preset sampling period, and calculate the pressure change rate within adjacent sampling periods; Step S2: During the cooking pressurization stage, the drive display screen shows a first dynamic pattern. The flow direction of the first dynamic pattern is from bottom to top, and the flow step frequency of the first dynamic pattern is positively correlated with the absolute value of the pressure change rate. Step S3: During the air-cooled depressurization stage, start the cooling fan and drive the display screen to show the second dynamic pattern, which is associated with the rotation state of the cooling fan; Step S4: Detect whether the float valve is seated. Step S5: When the float valve is detected to be seated, the second dynamic pattern is switched to an openable cover indicator, and the cooling fan is controlled to stop running after a delay period.

13. The display control method for an electric pressure cooker according to claim 12, characterized in that, The pressure change rate in step S1 is calculated by dividing the difference between the pressure value of the nth sampling and the pressure value of the (n-1)th sampling by the preset sampling period to obtain the pressure change rate.

14. The display control method for an electric pressure cooker according to claim 12, characterized in that, In step S2, after determining the flow step frequency based on the pressure change rate, the flow step frequency is limited to between a preset minimum step frequency and a preset maximum step frequency.

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