Control circuit for steam oven and steam oven

Abstract

The utility model relates to the technical field of kitchen equipment, and particularly discloses a control circuit of a steam oven and the steam oven, and the control circuit comprises a control mainboard, a temperature control switch, a humidity sensor, a relay, power supply equipment and a cooling fan. The temperature control switch is connected in series with the power supply equipment and the cooling fan to form a temperature control circuit; the control mainboard integrates a power transmission module and a signal transmission module, and a humidity threshold value is preset. When a detection value of the humidity sensor reaches a threshold value or the temperature control switch is triggered, the control mainboard conducts the relay coil, so that the power transmission module is connected, and the cooling fan is started. In addition, the circuit is applied to the steam oven. Compared with the prior art, the control circuit monitors the humidity change of the air duct in real time and intelligently triggers the cooling fan to start through a temperature and humidity dual detection mechanism, only operates when the temperature and the humidity exceed the standard, avoids electric energy waste, accurately controls the fan to start and stop to prevent water vapor condensation, and effectively solves the problem of steam condensation during cooking of the oven.

Description

Technical Field

[0001] This utility model relates to the field of kitchen equipment technology, specifically to a control circuit for a steam oven and a steam oven. Background Technology

[0002] Currently, steam ovens, regular ovens, or steam ovens produce a large amount of steam during cooking, which is usually discharged directly from the oven through the exhaust duct. However, steam easily condenses within the exhaust system, leading to rust, short circuits in electrical components, shortened product lifespan, and safety concerns. Simultaneously, the discharged steam condenses on the panel near the vent, damaging the appearance and reducing user experience. To address this, many manufacturers have installed cooling devices within the exhaust duct to condense the steam before discharge. However, during cooking, high-temperature steam rises through the exhaust pipe and accumulates in the cooling duct, requiring the airflow from the cooling fan to remove it from the oven. This necessitates the cooling fan running continuously from the start of cooking; otherwise, energy is wasted. To balance this, manufacturers have added a temperature-sensing mechanical control switch to the cooling motor, controlling the fan's activation based on temperature changes. However, the problem is that steam has already accumulated in the duct before the temperature control switch is activated, and may condense into water droplets on the oven panel through the vent.

[0003] In summary, starting the cooling fan is an effective way to eliminate water vapor condensation, but currently commonly used temperature detection and control methods all have obvious shortcomings. Utility Model Content

[0004] The purpose of this invention is to solve the problem of existing ovens using temperature detection control to control the cooling fan, and to provide a control circuit for a steam oven.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] The control circuit for a steam oven includes a control motherboard, a temperature switch, a humidity sensor, a relay, a power supply, and a cooling fan. The power supply and cooling fan are connected via the temperature switch to form a temperature control circuit. The control motherboard has a power transmission module and a signal transmission module, and a preset humidity threshold. The relay switch is located on the power transmission module. The input terminal of the power transmission module is connected to the power supply, and the output terminal is connected in parallel with the output terminal of the temperature control circuit. The input terminal of the signal transmission module is connected to the humidity sensor, and the output terminal is connected to the relay coil. When the detected humidity reaches the preset humidity threshold, the control motherboard drives the relay coil to conduct, thus connecting the input and output terminals of the power transmission module.

[0007] The control circuit of this utility model uses a temperature control switch and a humidity sensor for dual detection to ensure that the cooling fan can start in time when necessary, effectively preventing water vapor condensation. The humidity sensor monitors the humidity changes in the air duct in real time, realizing precise control of the cooling fan's start and stop. The cooling fan will only start when the temperature or humidity reaches the preset conditions, avoiding energy waste and water vapor condensation in the air duct. This achieves precise and timely control of the cooling fan and effectively solves the problem of water vapor condensation in the oven during cooking.

[0008] Another objective of this invention is to provide a steam oven with an electrical control unit located above the baking unit. The baking unit has a heating cavity, and the electrical control unit has an electrical control cavity. The control circuit is located in the electrical control cavity, and a cooling air duct is provided on the lower side of the electrical control cavity. One end of the cooling air duct is connected to the fan outlet, and the other end horizontally passes through the electrical control unit and connects to the outside. A heat insulation layer is provided above the heating cavity, and an exhaust pipe connecting the heating cavity and the cooling air duct is provided on the baking unit. This steam oven combines temperature and humidity detection methods to achieve precise control of the cooling fan, effectively preventing water vapor condensation. The baking unit and electrical control unit are designed separately. The baking unit is responsible for heating the food, while the electrical control unit is responsible for controlling the operation of the circuit and the cooling fan, reducing the impact of high temperatures on the control circuit and improving the stability and lifespan of the circuit. One end of the cooling air duct is connected to the cold air outlet of the cooling fan, and the other end passes through the electrical control unit and connects to the outside. This design ensures that the cold air generated by the cooling fan can effectively carry the steam out of the oven, preventing steam from accumulating in the air duct. An insulation layer is installed on the outside of the baking section to reduce heat transfer between the heating cavity and the electrical control cavity, ensuring a relatively stable temperature within the electrical control section. The application of the insulation layer lowers the operating temperature of the electrical control section, improves the reliability and stability of the control circuit, and reduces the risk of failure due to high temperatures.

[0009] Furthermore, the cooling fan is located in the middle and rear part of the electrical control cavity, with its cold air outlet at the front end. The cooling duct extends forward along the bottom wall of the electrical control cavity to the front end, and the exhaust pipe is connected to the bottom of the cooling duct. In this design, the cooling duct extends along the bottom wall to the front end of the electrical control cavity, allowing it to directly cover the area above the exhaust pipe. When high-temperature steam enters the cooling duct from the heating cavity through the exhaust pipe, cold air forms a "horizontal air curtain" from the bottom. This forces the steam to mix with the cold air in the early stages of its ascent, utilizing the low-temperature characteristics of the cold air to initiate a phase change and condensation of the steam in advance, reducing steam escape and preventing condensation from forming on the outer wall of the oven after the steam diffuses around.

[0010] Furthermore, the electronic control cavity is equipped with an air intake structure, which includes an air intake slot and a baffle plate. The air intake slot has a concave design, and the baffle plate covers the opening of the air intake slot, forming an airflow inlet between the baffle plate and the front end of the air intake slot. The exhaust pipe is connected to the bottom wall of the air intake slot, thus forming a guide channel with a "┐" shaped cross-section. This solution guides the air in the inner liner to the front of the cooling air duct through the design of the guide channel. The ingenious combination of the air intake slot and the baffle plate prevents cold air from the cooling air duct from entering the exhaust pipe. On the other hand, due to the unique shape design of the guide channel, when the airflow enters the cooling air duct, it will tend to move forward, avoiding steam backflow. Therefore, this design not only optimizes the airflow path but also effectively improves exhaust efficiency.

[0011] Furthermore, the top view of the air inlet slot is an expanding shape from back to front, and the exhaust pipe is located at the rear of the air inlet slot. The top view expansion of the air inlet slot and the rear placement of the exhaust pipe make the air inlet slot form a gradually expanding flow channel, with the output end cross-sectional area being larger than the input end. This reduces the airflow velocity, and the kinetic energy is insufficient for backflow. Combined with the baffle plate, this further blocks the return path.

[0012] Furthermore, the electrical control cavity includes an air guide housing, which is disposed at the cold air outlet of the cooling fan and forms the cooling air duct between the cooling fan and the bottom wall of the electrical control cavity.

[0013] Furthermore, the air guide housing includes a top air guide plate and a side air guide plate. The side air guide plate is connected between the top air guide plate and the top wall of the electrical control cavity, so that the cooling air duct is formed between the inner side of the air guide housing and the bottom wall of the electrical control cavity.

[0014] Furthermore, the front side of the top guide plate is provided with a sensing hole, through which the sensing heads of the temperature switch and humidity sensor extend into the cooling air duct.

[0015] Furthermore, the baking section includes a door assembly, an inner shell, and an outer shell. The heating cavity is located in the inner shell and extends through the front end of the inner shell. The outer shell covers the outside of the inner shell. The front ends of the inner shell and the outer shell are tightly fitted together. The door assembly is located at the front end of the baking section. The electrical control section includes an upper shell and a control panel. The front and lower ends of the upper shell are open and are located at the upper end of the outer shell, forming the electrical control cavity between the inner side of the upper shell and the upper side of the outer shell. The control panel is located at the front end of the upper shell and has a preset distance from the outer shell. The outlet of the cooling air duct is located between the control panel and the outer shell.

[0016] Furthermore, the height of the cooling duct gradually decreases from the inlet to the outlet, forming a slope of 15-30°, while the width gradually increases, creating an angle of 5-10 degrees between the middle and sides. In this design, the reduced height leads to a smaller cross-sectional area, enhancing the impact cooling effect on the steam. Simultaneously, the increased width leads to a larger cross-sectional area, converting kinetic energy into static pressure energy and reducing fan energy consumption. The coordinated changes in height and width create a spiral velocity distribution, enhancing airflow adhesion to the wall through the secondary flow effect, increasing the airflow rate in the middle and front of the cooling duct, and enhancing the impact cooling effect on the steam and control board.

[0017] Furthermore, the temperature switch is a snap-action normally open temperature controller. Attached Figure Description

[0018] Figure 1 It is the circuit schematic of the control circuit;

[0019] Figure 2 This is a cross-sectional view of a steam oven;

[0020] Figure 3 This is a cross-sectional view of a steam oven;

[0021] Figure 4 This is a schematic diagram of the air guide shell structure;

[0022] Figure 5 This is an exploded view of the structure of a steam oven;

[0023] Figure 6 This is a structural hierarchy diagram of the top cover plate;

[0024] Figure 7 This is a structural diagram of a steam oven;

[0025] Figure 8 This is a structural diagram of a steam oven.

[0026] Label Explanation:

[0027] 21. Control main board, 22. Temperature switch, 23. Humidity sensor, 24. Relay, 25. Power supply equipment, 26. Cooling fan, 1. Steam oven, 3. Baking section, 31. Heating cavity, 32. Door assembly, 33. Inner shell, 34. Outer shell, 341. Top cover, 44. Electrical control unit, 41. Upper shell, 42. Control panel, 43. Electrical control cavity, 44. Air inlet structure, 441. Air inlet slot, 442. Baffle plate, 45. Air guide shell, 451. Air guide top plate, 452. Air guide side plate, 453. Sensing hole, 46. Cooling air duct, 47. Main board mounting slot. Detailed Implementation

[0028] The technical solution of this utility model will be further described below with reference to the accompanying drawings:

[0029] In the description of this utility model, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "horizontal", "inner", and "outer" is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing this utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this utility model.

[0030] Example 1:

[0031] See Figure 1 As shown, this embodiment discloses a control circuit for a steam oven 1, including a control main board 21, a temperature switch 22, a humidity sensor 23, a relay 24, a power supply device 25, and a cooling fan 26. The power supply device 25 and the cooling fan 26 are connected through the temperature switch 22 to form a temperature control circuit. The control main board 21 is provided with a power transmission module and a signal transmission module, and has a preset humidity threshold. The switch of the relay 24 is located on the power transmission module. The input terminal of the power transmission module is connected to the power supply device 25, and the output terminal is connected in parallel with the output terminal of the temperature control circuit. The input terminal of the signal transmission module is connected to the humidity sensor 23, and the output terminal is connected to the coil of the relay 24. When the detected humidity reaches the preset humidity threshold, the control main board 21 drives the coil of the relay 24 to conduct, so that the input terminal and the output terminal of the power transmission module are connected.

[0032] The control circuit of this invention uses both a temperature switch 22 and a humidity sensor 23 for dual detection to ensure that the cooling fan 26 starts in a timely manner when necessary, preventing water vapor condensation. The humidity sensor 23 monitors the humidity changes in the air duct in real time and precisely controls the start and stop of the cooling fan 26: the fan is only started when the temperature or humidity reaches the preset conditions, avoiding energy waste and water vapor condensation in the air duct.

[0033] Example 2:

[0034] See Figure 2-8 As shown, this embodiment discloses a steam oven 1. The electrical control unit 4 is located above the baking unit 3. The baking unit 3 is provided with a heating cavity 31. The electrical control unit 4 is provided with an electrical control cavity 43. The control circuit is provided in the electrical control cavity 43. A cooling air duct 46 is provided on the lower side of the electrical control cavity 43. One end of the cooling air duct 46 is connected to the outlet of the cooling fan 26, and the other end horizontally passes through the electrical control unit 4 and communicates with the outside. A heat insulation layer is provided above the heating cavity 31. The baking unit 3 is provided with a smoke exhaust pipe that connects the heating cavity 31 and the cooling air duct 46.

[0035] The aforementioned cooling fan 26 is located in the rear part of the electrical control cavity 43, with its cold air outlet at the front end. The cooling air duct 46 extends forward along the bottom wall of the electrical control cavity 43 to the front end, and the exhaust pipe is connected to the bottom of the cooling air duct 46. When high-temperature steam enters the cooling air duct 46 from the heating cavity 31 through the exhaust pipe, the cold air forms a "horizontal air curtain" to force the steam to mix and condense in advance to reduce escape.

[0036] The aforementioned electrical control cavity 43 is equipped with an air inlet structure 44, including a recessed air inlet groove 441 and a baffle plate 442 covering the groove opening. The baffle plate 442 and the front end of the air inlet groove 441 form an airflow inlet. The exhaust pipe is connected to the bottom wall of the air inlet groove 441 to form a "┐" shaped guide channel, which blocks the cold air recirculation and optimizes the airflow path.

[0037] The aforementioned air guide housing 45 is positioned at the front end of the cold air outlet and includes a top guide plate 451 at an angle of 15-30° to the bottom wall and a side guide plate 452 connecting the top plate, forming a cooling air duct 46 on its inner side. The top guide plate 451 is provided with a main board mounting groove 47 (the bottom wall is parallel to the bottom wall of the electrical control cavity 43) to ensure uniform heat dissipation of the main control board 21.

[0038] The aforementioned top guide plate 451 has a sensing hole 453 on its front side, through which the sensing heads of the temperature switch 22 and humidity sensor 23 extend into the cooling air duct 46.

[0039] The baking section 3 includes a door assembly 32, an inner shell 33, and an outer shell 34. The heating cavity 31 penetrates the front end of the inner shell 33, and the outer shell 34 covers the outside of the inner shell 33. The electrical control section 4 includes an upper shell 41 and a control panel 42. The front and lower ends of the upper shell 41 are open, forming an electrical control cavity 43 between it and the top cover plate 341 of the outer shell 34. The outlet of the cooling air duct 46 is located between the control panel 42 and the outer shell 34.

[0040] The aforementioned cooling duct 46 gradually decreases in height (15-30° slope) from the inlet to the outlet, and gradually increases in width (5-10° angle between the middle and the side). This change in cross-sectional area enhances the steam impact cooling effect and reduces the fan energy consumption.

[0041] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to this utility model should also fall within the protection scope of the claims of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.

Claims

1. A control circuit for a steam oven, characterized by: The control mainboard is provided with a power supply transmission module and a signal transmission module, and is provided with a preset humidity threshold value, the switch of the relay is arranged on the power supply transmission module, the input end of the power supply transmission module is connected with the power supply device, and the output end is connected with the output end of the temperature control circuit in parallel, the input end of the signal transmission module is connected with the humidity sensor, and the output end is connected with the coil of the relay, when the detected humidity reaches the preset humidity threshold value, the control mainboard drives the coil of the relay to be turned on, so that the input end and the output end of the power supply transmission module are turned on.

2. A steam oven, characterized by: The control circuit comprises a baking part, an electric control part and the control circuit in claim 1, the electric control part is located above the baking part, the baking part is provided with a heating cavity, the electric control part is provided with an electric control cavity, the control circuit is arranged in the electric control cavity, a cooling air duct is arranged at the lower side of the electric control cavity, one end of the cooling air duct is connected with the outlet of the fan, and the other end is horizontally connected with the outside through the electric control part, a temperature insulation layer is arranged above the heating cavity, and a smoke exhaust pipe is arranged on the baking part and is connected with the heating cavity and the cooling air duct.

3. The steam oven according to claim 2, characterized in that: The cooling fan is located at the middle and rear part of the electric control cavity, and the cold air outlet of the cooling fan is located at the front end.

4. The steam oven according to claim 2, characterized in that: The electric control cavity is provided with an air inlet structure, the air inlet structure comprises an air inlet groove and a baffle, the air inlet groove is designed to be concave, the baffle is arranged on the groove opening of the air inlet groove, and the baffle and the front end of the air inlet groove form an air inlet.

5. The steam oven according to claim 4, characterized in that: The top view of the air inlet groove is in the shape of expanding from the rear to the front, and the smoke exhaust pipe is located at the rear part of the air inlet groove.

6. The steam oven according to claim 3, characterized in that: The electric control cavity comprises a wind guide shell, which is arranged at the cold air outlet of the cooling fan and forms the cooling air duct between the bottom wall of the electric control cavity.

7. The steam oven according to claim 6, characterized in that: The wind guide shell comprises a flow guide top plate and a flow guide side plate, the flow guide side plate is connected between the flow guide top plate and the top wall of the electric control cavity, so that the cooling air duct is formed between the inner side of the wind guide shell and the bottom wall of the electric control cavity.

8. The steam oven according to claim 7, characterized in that: The front side of the flow guide top plate is provided with a sensing hole, and the sensing head of the temperature switch and the humidity sensor extends into the cooling air duct through the sensing hole.

9. The steam oven of claim 2, wherein: The temperature switch is a snap type normally open temperature controller.

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