STEAM GENERATION CONTROL METHOD

Provided is a steam generation method for a steam generation system The method includes: S1, controlling the liquid pump (3) to operate, driving liquid from the liquid inlet (1) through the inlet valve (4) to the steam heater (5) in a heating state; S2, during the operation of the liquid pump (3), controlling the inlet valve (4) to alternately open and close at a preset frequency, causing the liquid to intermittently pass through the inlet valve (4). The liquid, after passing through the inlet valve (4), is delivered in a pulsed flow to the steam heater (5), where each pulsed flow continuously moves and is at least partially evaporated to produce steam before exiting the steam heater (5).

TECHNICAL FIELD

This application relates to the technical field of steam generation, and more particularly, to a steam generation control method.

BACKGROUND OF THE INVENTION

Steam has the characteristics of high temperature and the ability to produce a large amount of steam from a small amount of liquid water, making it widely applicable in fields such as cleaning, disinfection, and sterilization. Prior arts include products that use steam for cleaning and disinfection, such as steam car washers, steam mops, steam sterilizers, steam irons, and steam garment steamers.

However, in the prior art, steam generation typically relies on a boiler-based method where water is stored and heated until it evaporates. The boiler, a vessel used for heating, stores water that is heated either electrically or by fuel until it boils to produce steam. The generated steam is then output through a delivery pipeline. This method is slow because it requires heating all the water in the boiler to a boiling point. Some prior art has attempted to speed up steam production by reducing the boiler volume and replenishing water after evaporation. However, this results in discontinuous steam production. Additionally, controlling the dryness-and-humidity or wetness of the steam produced by these methods is challenging; the steam often has high humidity and is unsuitable for applications requiring dry steam. Furthermore, the steam, being a gas-liquid mixture with high humidity, often fails to reach the high temperatures needed for certain applications. Overall, the steam produced by the prior art lacks precise quality control, limiting the functionality and user experience of steam-based household products on the market.

In view of this, it is necessary to propose a new technical solution to address the aforementioned issues.

SUMMARY OF THE INVENTION

The present application provides a method for controlling steam generation that produces continuous, stable, and controllable quality steam.

The method is implemented through the following technical solution: A steam generation control method, applied to a steam generation system. The steam generation system includes a liquid inlet, a steam outlet, and a liquid pump, an inlet valve, and a steam heater connected between the liquid inlet and the steam outlet. The inlet valve is connected between the liquid inlet and the steam heater, and the liquid pump is connected between the inlet valve and the steam heater. The control method includes:S1, controlling the operation of the liquid pump to drive liquid from the liquid inlet through the inlet valve to the steam heater, which is in a heating state;S2, during the operation of the liquid pump, controlling the inlet valve to alternately open and close at a preset frequency, causing the liquid to intermittently pass through the inlet valve. The liquid passing through the inlet valve is delivered to the steam heater as a pulsed water flow.

Each pulsed water flow continues to move within the steam heater and is at least partially evaporated and vaporized to generate steam before exiting the steam heater.

As a further improvement, the pipeline between the inlet valve and the liquid pump, at least in the portion near the liquid pump, is filled with liquid, forming a filled section.

As a further improvement, the control method further includes: S3, controlling the heating of the steam heater and monitoring actual temperature of the steam heater; when the actual temperature of the steam heater reaches a preset temperature, executing the aforementioned steps S1 and S2.

As a further improvement, the steam outlet has open and closed states. When the steam outlet is in the closed state, the control method includes: controlling the steam heater to be in a heating state and intermittently operating the liquid pump and the inlet valve to intermittently supply water to the steam heater.

As a further improvement, when the steam outlet is in the closed state, the control method includes: controlling the steam heater to be in a heating state and monitoring the actual temperature of the steam heater. When the actual temperature of the steam heater reaches a first preset temperature, controlling the liquid pump to supply water to the steam heater; and when the actual temperature of the steam heater is below the first preset temperature, controlling the liquid pump to stop supplying water to the steam heater.

As a further improvement, when the steam outlet is in the closed state, the duration for which the actual temperature of the steam heater is below the first preset temperature is greater than the duration for which the actual temperature of the steam heater is at the first preset temperature.

As a further improvement, when the steam outlet is in the open state, the control method includes: controlling the steam heater to be in a heating state and continuously operating the liquid pump to supply water to the steam heater. The relationship between the heating of the steam heater and the water supply by the liquid pump is configured such that the amount of heat generated by the steam heater per unit time is not less than the amount of heat consumed by the water supplied by the liquid pump per unit time.

As a further improvement, when the steam outlet is in the open state, the control method includes: controlling the steam heater to be in a heating state, continuously operating the liquid pump to supply water to the steam heater, and monitoring the actual temperature of the steam heater. When the actual temperature of the steam heater reaches a second preset temperature, controlling the steam heater to maintain the second preset temperature.

As a further improvement, the first preset temperature is not less than the second preset temperature, with the second preset temperature being a temperature range.

As a further improvement, the steam generation system includes a steam gun head, with the steam outlet located within the steam gun head. The steam gun head has a trigger for switching the steam outlet between open and closed states.

As a further improvement, the steam gun head is provided with a mechanical switch and an electrical switch. The mechanical switch is positioned at the steam outlet to control the opening and closing of the steam outlet. The electrical switch is electrically connected to the liquid pump to control operation of the liquid pump. The trigger simultaneously activates both the mechanical switch and the electrical switch.

As a further improvement, the intermittent operation frequency of the liquid pump and the inlet valve is lower than the preset frequency for open-close alternating operation of the inlet valve.

As a further improvement, the control method includes: when the steam pressure within the steam generation system reaches a preset value, releasing steam through a relief valve to relieve the pressure.

As a further improvement, the liquid pump is an electromagnetic pump, and the inlet valve is an electromagnetic valve. The electromagnetic pump and the electromagnetic valve are controlled in synchronization.

As a further improvement, the control method includes: detecting the quality parameter information of the generated steam, as well as the operating parameter information of the steam heater and/or the inlet valve. If the detected steam quality parameter information does not meet the preset requirements, adjusting the operating parameter information of the steam heater and/or the inlet valve until the detected steam quality parameter information meets the preset requirements.

As a further improvement, the steam quality parameter information includes the steam dryness fraction; the operating parameter information of the steam heater includes the temperature value of the steam heater. When the detected steam dryness fraction exceeds the preset requirement, increasing the temperature value of the steam heater; when the detected steam dryness fraction is below the preset requirement, decreasing the temperature value of the steam heater.

As a further improvement, the operating parameter information of the inlet valve includes at least one of the following: the open-close frequency of the inlet valve, the duration of the open-close state, and the water intake volume.

As a further improvement, the control method further includes: detecting the temperature of the liquid before it enters the steam generation system, and setting the preset target temperature of the steam heater based on the temperature of the liquid. When the actual temperature of the steam heater reaches the preset target temperature, controlling the inlet valve to alternately open and close to supply water to the steam heater.

As a further improvement, the control method includes:

Controlling the inlet valve to alternately open and close at a first preset frequency, causing the liquid to intermittently pass through the inlet valve, forming a pulsed water flow that is delivered to the steam heater in a heating state; each pulsed water flow is at least partially evaporated into steam before exiting the steam heater, producing steam with a first steam dryness fraction;controlling the inlet valve to alternately open and close at a second preset frequency, causing the liquid to intermittently pass through the inlet valve, forming a pulsed water flow that is delivered to the steam heater in a heating state; each pulsed water flow is at least partially evaporated into steam before exiting the steam heater, producing steam with a second steam dryness fraction.

The first preset frequency is different from the second preset frequency, and/or the first preset temperature is different from the second preset temperature.

As a further improvement, the control method includes:receiving a trigger command to generate steam with a first steam dryness fraction;controlling the liquid pump to operate, and during the operation of the liquid pump, controlling the inlet valve to alternately open and close with a first opening duration and a first closing duration, forming a first pulsed water flow; the first pulsed water flow is delivered to the steam heater in a heating state for evaporation to produce the steam with a first steam dryness fraction;receiving a trigger command to generate steam with a second steam dryness fraction;controlling the liquid pump to operate, and during the operation of the liquid pump, controlling the inlet valve to alternately open and close with a second opening duration and a second closing duration, forming a second pulsed water flow; the second pulsed water flow is delivered to the steam heater in a heating state, where it is evaporated to produce steam with a second steam dryness fraction.

The first and second pulsed water flows both exhibit alternating strong and weak water flow stages, with strong water flow stages occurring when the inlet valve is open, and weak water flow stages occurring when the inlet valve is closed.

The second opening duration is shorter than the first opening duration, and the second closing duration is longer than the first closing duration, resulting in the steam generated with the second steam dryness fraction having lower moisture content than the steam generated with the first steam dryness fraction.

As a further improvement, the control method includes: pre-storing an information table that correlates steam dryness fractions with the preset temperatures of the steam heater and/or the preset frequencies of the inlet valve. When a command to generate steam with a certain dryness-and-dryness-and-humidity value is triggered, the corresponding data from the information table is retrieved, and the preset temperature of the steam heater and/or the preset frequency of the inlet valve is set accordingly.

The steam generation control method provided in this application controls liquid to be delivered as a pulsed water flow to the steam heater operating in a heating state. Each pulsed water flow continuously flows within the steam heater and is at least partially evaporated before exiting the steam heater. The control method uses pulsed water flow for water intake, ensuring that each pulsed water flow, while continuously flowing within the steam heater, is heated and evaporated. This approach allows for rapid steam generation, with the produced steam being continuous and of stable, controllable quality.

REFERENCE NUMERALS

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description pertains to exemplary embodiments, illustrated in the accompanying drawings. Unless otherwise indicated, the same or similar elements in different figures are denoted by the same reference numerals. The implementation methods described in the following exemplary embodiments do not represent all possible implementations consistent with this application; they are merely examples of devices and methods consistent with some aspects of this application.

In conjunction with the accompanying drawings, the steam generation control method provided by this application is described in detail. The features of the following embodiments can be combined with each other where they do not conflict.

Referring toFIGS.1to5, this application provides a steam generation control method applicable to a steam generation system. As illustrated inFIGS.1and2, which provide an embodiment of the steam generation system for the steam generation control method described in this application, the system includes a liquid inlet1, a steam outlet2, and a connection between the liquid inlet1and the steam outlet2comprising a liquid pump3, an inlet valve4, and a steam heater5. The inlet valve4is connected between the liquid inlet1and the steam heater5. The liquid inlet1, inlet valve4, liquid pump3, steam heater5, and steam outlet2are interconnected by pipelines. Liquid enters through the liquid inlet1, passes through the inlet valve4and liquid pump3, and then enters the steam heater5. In the steam heater5, the liquid is heated and evaporated into steam before being discharged through the steam outlet2. The liquid pump3, also referred to as a water pump, controls the intake or stoppage of water. In one embodiment, the liquid pump3is an electromagnetic pump. The inlet valve4controls the volume and manner of water intake. In one embodiment, the inlet valve4is an electromagnetic valve. The liquid pump3is positioned between the inlet valve4and the steam heater5. During operation, the liquid pump3generates pressure to drive the liquid into the steam heater5. Since the outlet of the liquid pump3is directly connected to the steam heater5, the pressure generated by the liquid pump3must be sufficient to overcome the pressure within the pipeline at the connection between the steam heater5and the liquid pump3to prevent backflow. Additionally, the presence of the liquid pump3between the inlet valve4and the steam heater5protects the inlet valve4from steam pressure from the steam heater5, ensuring the longevity and stability of the inlet valve4. The liquid pump3and the inlet valve4are controlled by correlated signals to ensure synchronized and coordinated operation.

Referring toFIG.3, the control method includes: S1, controlling the operation of the liquid pump3to drive liquid from the liquid inlet1through the inlet valve4and liquid pump3to the steam heater5, which is in a heating stateheating state; S2, during the operation of the liquid pump3, controlling the inlet valve4to alternately open and close at a preset frequency, causing the liquid to intermittently pass through the inlet valve4. The liquid passing through the inlet valve4forms a pulsed water flow, which is delivered to the steam heater5. Each pulsed water flow continues to move within the steam heater5and is at least partially evaporated to form steam before exiting the steam heater5.

In the control method provided by this application, water is introduced in a pulsed flow manner. Each pulsed water flow continuously moves within the steam heater5, where it is heated and evaporated, leading to rapid steam production. The pulsed water flow, characterized by alternating strong and weak flows, enters the steam heater5. This allows the steam heater5to quickly heat up and return to a balance temperature that can produce stable steam quality after the “peak segment” of each pulsed water flow is evaporated and before the arrival of the next “peak segment.” This process ensures that the state of the steam heater5is consistent or nearly consistent each time a pulsed water flow enters, preventing a temperature drop due to the evaporation of preceding water flow, thereby producing steam with lower humidity and ensuring continuous, stable, and controllable steam quality.

In this embodiment, the liquid pump3is positioned between the inlet valve4and the steam heater5. The liquid pump3operates continuously during water intake control rather than intermittently, providing constant water pressure to prevent steam backflow into the steam heater5, which also reduces wear and tear on the liquid pump3. Since the inlet valve4only serves to control the flow of water without providing the driving force for the liquid flow, it does not require a large starting force. Therefore, the open-close frequency of the inlet valve4can be much higher than the operating frequency of the liquid pump3. In this embodiment, the pipeline between the inlet valve4and the liquid pump3is filled with liquid, or at least a section near the liquid pump3is filled with liquid. During the operation of the liquid pump3, the alternate opening and closing of the inlet valve4create two alternating states for the liquid between the inlet valve4and the liquid pump3: one where both the liquid pump3and inlet valve4are open, and the other where the liquid pump3is open but the inlet valve4is closed. When both the liquid pump3and the inlet valve4are open, the liquid between them flows freely. The driving force from the liquid pump3can push a certain amount of liquid through the liquid pump3toward the steam heater5while drawing in liquid from the liquid inlet1through the inlet valve4into the section between the liquid pump3and inlet valve4. In this state, the flow towards the steam heater5is greater, forming the strong segment of the pulsed flow. When the liquid pump3is open, but the inlet valve4is closed, the upstream liquid is cut off, creating a closed environment between the liquid pump3and the inlet valve4. The liquid pump3must overcome negative pressure to move the liquid toward the steam heater5, resulting in a smaller flow rate, forming the weak segment of the pulsed flow. When the inlet valve4alternately opens and closes at a certain frequency, the water flow from the liquid pump3forms a continuous pulsed flow with alternating strong and weak segments, delivered to the steam heater5. This approach ensures that the water entering the steam heater5is continuous, and even a small amount of water can generate a large amount of steam. Therefore, the steam produced does not exhibit noticeable interruptions or variations in quantity, resulting in continuous and stable steam production.

Referring toFIG.4, in a further improved embodiment of the control method described in this application, the method for generating steam includes: S3, controlling the heating of the steam heater5and monitoring the actual temperature of the steam heater5. When the actual temperature of the steam heater5reaches the preset temperature, the above-mentioned steps S1 and S2 are executed.

In this embodiment, by preheating the steam heater5and controlling water intake only when the preheating reaches the preset temperature, it ensures that the incoming water can immediately produce steam of the desired quality. Compared to some prior art where water intake triggers heater activation, this approach avoids issues with initial steam quality instability and reduces water wastage. In this embodiment, the steam quality includes the steam dryness fraction of the steam, and the preset temperature is set in relation to the amount of water intake controlled by the liquid pump3and the inlet valve4, as well as the desired steam dryness fraction of the steam. When the water intake amount controlled by the liquid pump3and the inlet valve4is constant, the preset temperature of the steam heater5is set higher to produce drier steam (i.e., steam with lower humidity). Conversely, to produce wetter steam (i.e., steam with higher humidity), the preset temperature of the steam heater5is set lower. Furthermore, in this embodiment, the controller automatically triggers the operation of the liquid pump3and the inlet valve4for water intake based on the detected actual temperature of the steam heater5, achieving precise timing for water intake control. This approach prevents steam quality instability due to premature water intake and avoids overheating of the steam heater5due to delayed water intake.

Referring toFIG.5, in a further improved embodiment based on the control method shown inFIG.3, the steam outlet2has an open state and a closed state. When the steam outlet2is in a closed state, the control method includes controlling the steam heater5to remain in a heating stateheating state and intermittently operating the liquid pump3and the inlet valve4to intermittently supply water to the steam heater5.

In a specific embodiment, the open and closed states of the steam outlet2are manually controlled by the user, allowing the user to control the shutdown and discharge of steam at any time. For example, in one embodiment, the liquid evaporated into steam in the steam heater5is delivered through a steam pipeline to a handheld steam gun head6used by the user. The steam outlet2is located within the steam gun head6, which is provided with a trigger61. The user can squeeze and release the trigger61to switch the steam outlet2between open and closed states. In one embodiment, the steam gun head6includes both a mechanical switch and an electrical switch. The mechanical switch is positioned at the steam outlet2to control opening and closing of the steam outlet2, while the electrical switch is electrically connected to the liquid pump3to control operation of the liquid pump3. The trigger simultaneously activates both the mechanical switch and the electrical switch.

In the embodiment shown inFIG.5, when the steam outlet2is in a closed state, the steam generated within the steam generation system cannot be discharged through the steam outlet2. If steam continues to be produced in large quantities under these conditions, it can lead to excessively high pressure within the steam generation system, posing safety risks to both the system and the user. In this embodiment, when the steam outlet2is closed, the method involves controlling the steam heater5to remain in a heating stateheating state and intermittently operating the liquid pump3and the inlet valve4to intermittently supply water to the steam heater5. This setup has the following benefits: Keeping the steam heater5in a heating stateheating state ensures that steam can be promptly produced when the user opens the steam outlet2. Users frequently need to start and stop the steam flow, and if the steam heater5stops heating while the steam outlet2is closed, the temperature of the steam heater5drops. If the steam outlet2remains closed for an extended period, the temperature of the steam heater5decreases significantly, resulting in steam that does not meet the desired quality when the steam outlet2is reopened. For instance, if a user closes the steam outlet2for a period while using drier steam for dry cleaning clothes, reopening it may result in steam with higher humidity, causing the clothes to become damp. On the other hand, if the steam heater5continues heating and water is continuously supplied, a large amount of steam would be produced, potentially raising the pressure within the steam generation system to unsafe levels. If no water is supplied, the steam heater5could overheat due to dry firing. Therefore, in this embodiment, while keeping the steam heater5heated, the method controls the liquid pump3and the inlet valve4to intermittently supply water to the steam heater5. This approach prevents excessive steam generation when the outlet is closed, thereby avoiding the risk of pressure buildup. It also prevents the steam heater5from overheating due to lack of water, maintaining system safety and steam quality.

Furthermore, the control of the steam heater5in a heating state and the intermittent operation of the liquid pump3and the inlet valve4to supply water intermittently to the steam heater5includes controlling the steam heater5to operate and monitoring operational state of the steam heater5. When the operational state of the steam heater5reaches a preset condition, the liquid pump3and the inlet valve4are controlled to supply water to the steam heater5. If the operational state of the steam heater5does not meet the preset condition, the liquid pump3and the inlet valve4are controlled to stop supplying water to the steam heater5. This intermittent water supply process is automatically triggered by a controller based on the detected operational state of the steam heater5, effectively controlling and maintaining the operational state of the steam heater5, preventing actual operational state of the steam heater5from deviating excessively from the state required to produce steam of the preset quality, ensuring the continuous production of quality-controlled steam. The preset condition of the operational state can be based on reaching a preset time, preset pressure, or preset temperature, or a combination of these factors. In one embodiment, the operational state of the steam heater5reaches the preset condition when the actual temperature of the steam heater5reaches a first preset temperature. Specifically, when the steam outlet2is closed, water intake is controlled based on the temperature of the steam heater5. When the temperature of the steam heater5reaches the first preset temperature, the liquid pump3and inlet valve4are controlled to supply water, during which the temperature of the steam heater5may drop below the first preset temperature, prompting the liquid pump3and inlet valve4to stop water intake. Once the temperature rises back to the first preset temperature, water intake resumes, achieving intermittent water supply. This setup ensures that when the steam outlet2is closed, there is no immediate need to discharge steam, and temperature-controlled water intake maintains the “stored” steam within the system near the desired quality. When the steam outlet is open and steam is urgently needed, the “stored” steam can be immediately used, while new steam is generated, ensuring no delay in steam production. During the intermittent water supply process, the primary control of water intake and stoppage is managed by the liquid pump3, with the inlet valve4primarily facilitating the pulsed water flow during the water intake phase. In other words, the frequency of intermittent operation of the liquid pump3and inlet valve4is lower than the preset frequency for the alternating open-close operation of the inlet valve4, meaning that during one cycle of intermittent water intake, the inlet valve4still undergoes multiple alternating open-close cycles.

As described above, although intermittent water supply can prevent the generation of a large amount of steam, some steam will still be produced. Therefore, in one embodiment, when the steam outlet2is closed, the duration during which the actual temperature of the steam heater5remains below the first preset temperature is longer than the duration during which the actual temperature is at the first preset temperature. This means that during intermittent water supply, the period of water intake is shorter than the period of no water intake, thereby reducing the frequency of water intake and the amount of steam produced. Further, in this embodiment, the steam generation system also includes a pressure relief valve7. The control method additionally includes releasing steam through the pressure relief valve7to relieve pressure when the steam pressure within the steam generation system reaches a preset value.

When the steam outlet2is in an open state, the control method includes controlling the steam heater5to remain in a heating state and operating the liquid pump3and the inlet valve4to supply water. The relationship between the heating provided by the steam heater5and the water intake controlled by the liquid pump3and the inlet valve4is configured such that the amount of heat generated by the steam heater5per unit time is not less than the amount of heat consumed by the water intake controlled by the liquid pump3and the inlet valve4per unit time.

Specifically, when the steam outlet2is open, continuous water supply to the steam heater5is maintained to ensure continuous steam production. To prevent the temperature of the steam heater5from dropping during continuous water intake, the heat generated by the steam heater5per unit time must be at least equal to the heat consumed by the water intake controlled by the liquid pump3and the inlet valve4per unit time. This configuration ensures that during continuous water intake, the steam heater5can increase from a temperature below the preset temperature to the preset temperature and maintain it within the preset temperature range. The preset temperature may be defined as a temperature range, where “heating to the preset temperature” refers to heating to the lower limit of this range, and “maintaining the preset temperature” refers to keeping the temperature within the upper and lower limits of this range. Additionally, it should be noted that the term “continuous water supply” here is relative to the intermittent water supply when the steam outlet2is closed. This continuous water supply does not change the pulsed water flow method controlled by the inlet valve4.

When the steam outlet2is in an open state, the control method includes controlling the steam heater5to remain in a heating state, and continuously operating the liquid pump3to supply water to the steam heater5. The actual temperature of the steam heater5is monitored, and when it reaches a second preset temperature, the steam heater is controlled to maintain this second preset temperature. The first preset temperature is not less than the second preset temperature, with the second preset temperature being defined as a temperature range.

The steam generation control method provided in this application can be used to produce steam with one or more preset steam dryness fraction. The preset steam dryness fraction of the steam are achieved by matching the preset frequency of the open-close operation of the inlet valve4with the heating of the steam heater5. For example, when the inlet valve4is controlled to alternately open and close at a first preset frequency, the liquid passing through the inlet valve4is delivered in a pulsed flow to the steam heater5set at a first preset temperature, resulting in steam with a first steam dryness fraction. When the inlet valve4is controlled to alternately open and close at a second preset frequency, the liquid passing through the inlet valve4is delivered in a pulsed flow to the steam heater5set at a second preset temperature, resulting in steam with a second steam dryness fraction. The first preset frequency differs from the second preset frequency, and/or the first preset temperature differs from the second preset temperature, thus achieving different steam dryness fractions for the steam. Since the preset frequency of the inlet valve4affects both the pulsed water flow and the amount of water intake, different steam dryness fractions of steam can also be produced by changing the preset temperature of the steam heater5without altering the preset frequency of the inlet valve4. For instance, the first and second preset frequencies can be set to the same, with the first preset temperature higher than the second preset temperature, resulting in the steam with first steam dryness fraction having a lower humidity than the steam with second steam dryness fraction.

In one embodiment, the method for generating steam with different steam dryness fraction includes:receiving a trigger command to produce steam with a first steam dryness fraction;controlling the operation of the liquid pump3and, during operation of the liquid pump3, controlling the inlet valve4to alternately open for a first opening duration and close for a first closing duration, thereby creating a first pulsed water flow; the first pulsed flow is delivered to the steam heater5in a heating state; in the steam hater5, the first pulsed flow is evaporated to produce steam with the first steam dryness fraction;receiving a trigger command to produce steam with a second steam dryness fraction; andcontrolling the operation of the liquid pump3and, during operation of the liquid pump3, controlling the inlet valve4to alternately open for a second opening duration and close for a second closing duration, thereby creating a second pulsed water flow; the second pulsed water flow is delivered to the steam heater5in a heating state; in the steam heater5, the second pulsed water flow is evaporated to produce steam with the second steam dryness fraction.

Both the first pulsed water flow and the second pulsed water flow consist of continuous flows with alternating strong and weak segments. The strong segment occurs when the inlet valve4is open, forming a strong water flow, and the weak segment occurs when the inlet valve4is closed, forming a weak water flow.

The second opening duration is shorter than the first opening duration, and the second closing duration is longer than the first closing duration, resulting in the steam produced with the second steam dryness fraction having lower humidity than the steam produced with the first steam dryness fraction.

The control method of this application generates pulsed water flow with continuous variations in intensity. During one open-close cycle of the inlet valve4, the reduced water intake during the strong flow segment, caused by a shorter open duration, can be compensated by increasing the water intake during the weak flow segment by lengthening the closed duration of the inlet valve4. This adjustment helps prevent significant changes in the amount of steam produced when altering the dryness-and-humidity of the steam. Optionally, during one open-close cycle of the inlet valve4, the open duration can range from 0.01 to 0.2 seconds, and the closed duration can range from 1 to 3 seconds. By adjusting the open and closed durations of the inlet valve4, the quality of the steam produced can be modified, allowing for the production of steam with varying steam dryness fractions. For example, in the process of controlling the generation of steam with a certain steam dryness fraction, the inlet valve4may have an open duration of 0.1 seconds and a closed duration of 1.3 seconds, repeating alternately. In the process of controlling the generation of steam with another steam dryness fraction, the inlet valve may have an open duration of 0.05 seconds and a closed duration of 1.6 seconds, also repeating alternately.

In one embodiment, the heating power of the steam heater5remains the same when producing steam with both the first and second steam dryness fractions. That is, the heating power of the steam heater5is not differentially controlled based on the dryness-and-humidity of the steam. Instead, the adjustment is made solely through the control of the water intake state via the inlet valve4. By matching the water intake state and amount controlled by the inlet valve4with the rated heating power of the steam heater5, the temperature of the steam heater5can be maintained within a corresponding balance temperature range for different steam dryness fractions. For instance, when producing relatively wetter steam, the balance temperature range of the steam heater5is 180° C.-190° C., while for producing relatively drier steam, it is 240° C.-250° C. Furthermore, to prevent the temperature of the steam heater5from continually rising due to minimal water intake, which could destabilize it from staying within the balance temperature range, an overheat protection device is provided on the steam heater5. This device stops the heating of the steam heater5when temperature of the steam heater reaches an overheat protection threshold (e.g., 280° C.). In a specific embodiment, the overheat protection device includes a temperature sensor that is electrically connected to the controller of the steam heater5. The controller uses the temperature detected by the sensor to manage the heating of the steam heater5.

In this embodiment, the heating power of the steam heater5is not differentially controlled when producing steam with varying steam dryness fractions, making the control process simpler. More importantly, this approach enhances precision because steam heaters are often provided with good insulation measures, such as thermal insulation cotton, to achieve better thermal efficiency and reduce heat loss. The good insulation performance of the steam heater5results in a slower rate of temperature change (thermal inertia), making it difficult to quickly adjust the temperature by changing the heating power. By controlling the water intake amount and state, this embodiment allows the steam heater5to achieve a thermal balance with the incoming water, maintaining the steam heater5within a balance temperature range suitable for producing steam with a specific steam dryness fraction.

This embodiment provides a method for controlling steam generation that can produce steam with adjustable quality. The method specifically involves controlling the inlet valve4to alternately open and close at a certain frequency, thereby creating a pulsed water flow. As each pulsed water flow moves through the steam heater5, it is at least partially evaporated to form steam. During the steam generation process, the quality parameters of the steam are monitored, and the operating parameters of the inlet valve are dynamically adjusted to maintain stable steam quality.

Specifically, the control method includes detecting the quality parameter information of the generated steam and the operating parameter information of the steam heater5and/or the inlet valve4. If the detected steam quality parameters do not meet the preset requirements, the operating parameters of the steam heater5and/or the inlet valve are adjusted until the detected steam quality parameters meet the preset requirements.

Furthermore, the steam quality parameters include the humidity level of the steam, while the operating parameters of the steam heater5include temperature of the steam heater5. If the detected steam humidity level exceeds the preset required humidity level, the temperature of the steam heater5is increased. Conversely, if the detected steam humidity level is below the preset required level, the temperature of the steam heater5is decreased. The operating parameters of the inlet valve4include the open-close frequency, the duration of the open and close states, and the amount of water intake, at least one of which can be adjusted.

Additionally, to ensure that the initial quality of the steam generated closely matches the desired steam quality, allowing for only minor adjustments to achieve the final desired steam quality, the control method also includes a preheating step where the target temperature of the steam heater5is calculated in advance. Specifically, the control method includes: detecting the temperature of the liquid before it enters the steam generation system, and setting a target temperature for the steam heater5based on the detected liquid temperature. When the actual temperature of the steam heater5reaches this target temperature, the inlet valve4is controlled to alternately open and close to supply water to the steam heater5. Since the initial temperature of the liquid is the most significant factor affecting the heating process of the steam heater5, this embodiment uses this key factor to preliminarily calculate the approximate temperature value of the steam heater5corresponding to the desired steam quality, which is set as the target temperature. Once the steam heater5reaches this target temperature, water intake is controlled. While the steam produced at the target temperature of the steam heater5may not exactly match the desired steam quality, it is usually quite close, and further adjustments to the preset temperature of the steam heater5can quickly achieve the desired steam quality, enhancing the user experience.

In one embodiment, the method for producing steam with stable quality includes: controlling the operation of the liquid pump3, and during operation of the liquid pump3, controlling the inlet valve4to alternately open and close at a preset frequency, creating a pulsed water flow that is delivered to the steam heater5in a heating state, where it is evaporated to produce steam. In each open-close cycle of the inlet valve4, the valve remains open for a first duration and closed for a second duration.

The quality parameters of the produced steam are monitored; if the detected steam quality parameters do not meet the preset requirements, the duration of the open and closed states of the inlet valve4are adjusted until the steam quality parameters meet the preset requirements.

The steam quality parameters include the humidity level of the steam. Adjusting the duration of the open and closed states of the inlet valve4involves either increasing the first duration and decreasing the second duration, or decreasing the first duration and increasing the second duration. In one embodiment, a check valve8is installed between the liquid pump3and the steam heater5, allowing one-way flow from the liquid pump3to the steam heater5. The check valve8prevents backflow of steam, which supports the pulsed water flow method.

From the description of the specific embodiments above, it is evident that the steam generation control method provided by this application involves controlling the liquid to be delivered in pulsed water flows to the steam heater5, which is in a heating state. Each pulsed water flow continues to move within the steam heater5and is at least partially evaporated before exiting the steam heater5. This control method, which uses pulsed water flows, ensures that each flow is heated and evaporated within the steam heater5, resulting in rapid steam production, continuous output, and stable, controllable steam quality.

The above description is merely a preferred embodiment of this application and is not intended to limit the scope of the application in any way. Although this application has been disclosed with preferred embodiments, it is not limited to these embodiments. Any person skilled in the art may make slight modifications or equivalent changes to these embodiments based on the disclosed content without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes, and adjustments made to the above embodiments without departing from the technical essence of this application are still within the scope of the technical solutions claimed in this application.