Water scale detection method of heating body, steam device and storage medium

Abstract

The invention discloses a scale detection method of a heating body, a steam device and a storage medium, and relates to the technical field of scale detection. The method comprises the following steps: specifically setting the heating power P of a heating body, the rated temperature T of water body heating, the water inlet flow Q of the heating body, an energy efficiency threshold value eta m, the collection heating time t, and the inlet temperature T1 and the outlet temperature T2 of the heating body, and obtaining the temperature difference delta T of the inlet temperature T1 and the outlet temperature T2; carrying out scale detection on the heating body at a constant heating power P, and determining the mutual relation among the energy efficiency ratio eta, the flow velocity V, the heating power P, the cross section S, the energy efficiency threshold eta m and the flow velocity threshold Vm; therefore, the condition that the incrustation hinders the temperature rise of the water body can be accurately deduced, the heating body does not need to be kept in a continuous working state, the whole judgment process is more convenient, the service life of the heating body is prolonged, and the condition that the heating body is easily damaged after being detected under the high-temperature condition for a long time is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of scale detection, and in particular to a scale detection method for a heating body, a steam device and a storage medium. Background Art

[0002] Heating elements are devices or apparatus designed to heat water. Their functions are not limited to heating water, but also include maintaining water temperature, providing domestic hot water, industrial water, hydrotherapy and medical water, etc. Heating elements increase the temperature of water by generating heat and transferring heat to water.

[0003] During the heating process of the heating body, due to the deposition of minerals in the water, such as calcium and magnesium, calcium bicarbonate and magnesium bicarbonate in the water will decompose to form water-insoluble calcium carbonate and magnesium hydroxide. These substances will be deposited on the surface of the heating body, forming the so-called scale. For the evaporator, the evaporation of water will also increase the concentration of minerals in the water, further promoting the formation of scale. The presence of scale will reduce heating efficiency, increase energy consumption, and may even damage the heating equipment in severe cases. Regular descaling is an important part of maintaining the performance of the heating body. Therefore, when the heating body is in use, it is necessary to descale the heating body regularly.

[0004] At present, with the iteration of technology, people have found that there is a difference in temperature when the heating body is in use and when there is scale and no scale. The temperature of the heating body is periodically detected, and the temperature value in each cycle is subtracted to obtain the temperature difference in different cycles. In this way, the scale situation in the heating body can be judged without disassembling the heating body, which serves as an important basis for subsequent maintenance.

[0005] However, after full consideration by the inventors, it was found that there are still some shortcomings in the above. Since the temperature difference of different periods is used to obtain the scale condition of the heating body, the heating body needs to be in a state of continuous working to detect the specific situation of the scale, so as to make a more accurate judgment. The existence of scale on the heating body will cause the heating body to continue to heat up when the heating body continues to work, wasting more heat, and also causing the heating body to be damaged by the high temperature generated by the continuous work.

[0006] Therefore, the present application is to more accurately determine the scale situation when the heater is not working continuously, while also preventing the heater from being easily damaged by the high temperature generated by continuous operation. Summary of the invention

[0007] The main purpose of the present invention is to provide a method for more accurately determining the scale situation when the heater is not working continuously, while also preventing the heater from being easily damaged due to the high temperature generated by continuous operation.

[0008] In order to achieve the above object, the present invention provides a scale detection method for a heating body, the detection method comprising:

[0009] Set the heating power P of the heating body, the rated temperature T of the water body, the water flow rate Q of the heating body, and the energy efficiency threshold η m , collect the heating time t, the inlet temperature T1 and the outlet temperature T2 of the heating body, and obtain the temperature difference ΔT between the inlet temperature T1 and the outlet temperature T2; wherein η is the energy efficiency ratio of the heating body, C is the specific heat capacity of the fluid; ρ is the density of the fluid; S is the cross-section of the water flowing through the heating body, V is the flow rate of the water flowing through the cross-section of the heating body, U is the voltage of the heating body, and R is the resistance of the heating body;

[0010] The scale detection of the heating body is carried out at a constant heating power P. The scale detection formula is:

[0011]

[0012] When the outlet temperature T2 reaches and remains constant at the rated temperature T, the flow rate V is constant and the energy efficiency ratio η is at the energy efficiency threshold η m Below, it indicates that the heating body needs to be treated with scale warning; if the energy efficiency ratio is within the energy efficiency threshold η m The above indicates that the heating body works normally, or the energy efficiency ratio η is constant, the voltage U of the heating body is obtained, and the corresponding flow rate threshold V is set m , if the flow rate V is greater than the flow rate threshold V m When the flow rate V is constant at the flow rate threshold V m If the value is within 0.1, it indicates that the heater is working normally.

[0013] Furthermore, PID is used to adjust the flow rate V, including:

[0014] Δu[t]=u[t]-u[t-1]

[0015] =K p [e[t]-e[t-1]]+K i e(t)+K d [e[t]-2e[t-1]+e[t-2]];

[0016] Among them, K p , K i , K d are the proportional, integral and differential gains respectively, e[t] is the error between the current temperature and the rated temperature T, and u[t] is the compensation amount of the flow rate V of the heating body.

[0017] Further, when the heating body completes heating, the heating power P is set to zero, the outlet temperature T2 of the heating body is the rated temperature T, and water is supplied to the heating body to reduce the outlet temperature T2 from the rated temperature T to the intermediate temperature T. h , the intermediate temperature T h At least greater than the boiling point of water, set and obtain the heating body from the rated temperature T to the intermediate temperature T h The threshold time t m and the time required t s , when t s Equal to t m or beyond t m When the scale warning treatment is required, it indicates that the heating element needs to be treated.

[0018] Furthermore, the heat required to heat the water to a rated temperature T is recorded as q, and the rated temperature T is greater than the boiling point of the water. q is expressed as:

[0019] q=q1+q2+q3;

[0020] Among them, q1 represents the heat required to heat the water to the boiling point; q2 represents the heat required to heat the steam from the boiling point to the rated temperature T; q3 represents the latent heat of evaporation of the water into steam at the boiling point.

[0021] Furthermore, the heat relationship required for q1 is:

[0022] q1=ρ1·V1·c1·ΔT1;

[0023] The heat relationship required for q2 is:

[0024] q2=ρ2·V2·c2·ΔT2;

[0025] Among them, ρ1 is the density of water, V1 is the volume of water, c1 is the specific heat of water, ΔT1 is the temperature difference from water to boiling point; ρ2 is the density of steam, V2 is the volume of steam, c2 is the specific heat of steam; ΔT2 is the temperature difference of steam from boiling point to the rated temperature T.

[0026] Furthermore, the scale warning process includes at least one of a sound alarm, an information prompt and a scale treatment action. When the heating body is cleaned and then turned on again, if the heating body is turned on without being cleaned, the scale warning process is performed again or the heating body is turned off.

[0027] The present application also discloses a steam device, comprising a processor and a memory, wherein the memory can store a computer program on the processor; when the processor runs the computer program, the processor executes the steps of the above method.

[0028] The present application also discloses a storage medium, in which a computer program is stored. When the computer program is executed by a processor, the steps of the above method are executed.

[0029] The above technical solution has the following advantages:

[0030] The present invention uses a constant heating power and a limited flow rate to calculate the heating power and the actual power consumption, calculates the energy efficiency ratio of the heating body within the set different time periods, and calculates the energy efficiency ratio according to the energy efficiency ratio and the normal energy efficiency threshold η. m By comparison, the energy efficiency ratio can also be limited. The flow rate and flow rate threshold are used for comparison to obtain the scale situation in the heating body, making the scale situation in the heating body more intuitive and accurate. At the same time, it can be obtained without disassembly. In addition, the heating body only needs to detect the energy efficiency ratio within the time to obtain the scale situation inside it. There is no need to keep the heating body in a continuous working state, which makes the entire judgment process more convenient, which is beneficial to improving the service life of the heating body and avoiding damage caused by long-term exposure to high temperature.

[0031] After the heating element is heated, the required time t s and threshold time t m Compare, when t s Equal to t m or beyond t m It indicates that the heating body needs to be scale-warned, and there is no need to reheat the heating body for detection, which reduces energy consumption. It can also avoid the danger of scale detection when the heating body needs to be heated to the rated power T before working, so as to avoid the situation where the user repeatedly turns it on and repeats the heating detection. In addition, when the water passes through the front half of the heating body, this part is in a heating state and has a high scale content, while the back half of the heating body is water vapor with a low scale content. After the heating body is completed, the water vapor will gradually drive the scale particles from the heating body to be directly discharged as wastewater, reducing the scale content in the front half of the heating body and improving the heat transfer efficiency of the heating body. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention is described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0033] Figure 1 It is a structural schematic diagram of the present invention;

[0034] Figure 2 A circuit connection diagram of the present invention;

[0035] Figure 3 It is a curve diagram of the scale on the heating body of the present invention;

[0036] Figure 4 It is a curve diagram of the heating body of the present invention without scale;

[0037] Figure 5 The heating element of the present invention is cooled from the rated temperature T to the intermediate temperature T h Schematic diagram of

[0038] Figure 6 It is a flow chart of the heating body of the present invention.

[0039] In the figure: 1. Water inlet pipe; 2. Water outlet pipe; 3. Temperature sensor. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and do not constitute a limitation to the present invention.

[0041] Heating bodies can be used in different fields, such as electric water heaters, steam cabinets, steam bun machines, electric kettles, water dispensers, instant heating modules, etc. in household appliances; heating furnaces, boilers, etc. in the industrial field; heat exchangers in medicine and medical treatment; with long-term use, the scale inside them will gradually accumulate. The accumulation of scale will not only affect the heating efficiency of the steam cabinet, but also may damage the equipment and even affect the safety and quality of food. For users, regular manual observation and regular maintenance are common means. If the observation is not careful or the maintenance is improper, the observation also requires regular disassembly of the heating body, and the internal scale is observed and judged to determine whether the heating body needs to be descaled. However, the disassembly of this method is too cumbersome, which will also increase the burden of observation by personnel, resulting in low efficiency in observation and maintenance of the heating body. Professionals are also required to make judgments. It is difficult for users to be sure of the specific situation. Users rely on their own feelings to make judgments and there is no specific basis for determination. Therefore, they often make misjudgments. Professionals will also rely on the knowledge blind spots of users to make misleading operations, thereby increasing costs and greatly reducing user experience.

[0042] Based on this, in various embodiments of the present invention, by judging the heating power and water inlet flow at different times, the efficiency of water heating is obtained by using the energy efficiency ratio method, which can directly reflect the scale situation in the heating body, thereby making accurate judgments.

[0043] like Figure 6 As shown, an embodiment of the present invention provides a scale detection method for a heating body, the detection method comprising:

[0044] Set the heating power P of the heating body, the rated temperature T of the water body, the water flow rate Q of the heating body, and the energy efficiency threshold η m, collect the heating time t, the inlet temperature T1 and the outlet temperature T2 of the heating body, and obtain the temperature difference ΔT between the inlet temperature T1 and the outlet temperature T2; wherein η is the energy efficiency ratio of the heating body, C is the specific heat capacity of the fluid; ρ is the density of the fluid; S is the cross-section of the water flowing through the heating body, V is the flow rate of the water flowing through the cross-section of the heating body, U is the voltage of the heating body, and R is the resistance of the heating body;

[0045] The scale detection of the heating body is carried out at a constant heating power P. The scale detection formula is:

[0046]

[0047] When the outlet temperature T2 reaches and remains constant at the rated temperature T, the flow rate V is constant and the energy efficiency ratio η is at the energy efficiency threshold η m Below, it indicates that the heating body needs to be treated with scale warning; if the energy efficiency ratio is within the energy efficiency threshold η m The above indicates that the heating body works normally, or the energy efficiency ratio η is constant, the voltage U of the heating body is obtained, and the corresponding flow rate threshold V is set m , if the flow rate V is greater than the flow rate threshold V m When the flow rate V is constant at the flow rate threshold V m If the value is within 0.1, it indicates that the heater is working normally.

[0048] like Figure 1 As shown, during the data acquisition process, the water inlet flow rate Q is set at the water inlet end of the heating body, that is, at the water inlet pipe 1 of the heating body, so as to obtain the water flow flowing into the heating body. Specifically, a flow meter can be installed on the water inlet pipe 1 of the heating body to detect the specific water inlet flow rate Q; the heating power P is the electric energy consumed by the heating body, which is preferably achieved by electric heating. In addition, natural gas heating can also be used. Specifically, the volume of natural gas can be calculated, and the energy that can be released by the natural gas in this volume is used to calculate the heating power P, so as to achieve energy conversion; the inlet temperature T1 is a constant value, that is, the real-time temperature of normal temperature water, and the outlet temperature T2 is the real-time temperature of the water outlet or gas outlet of the heating body. Specifically, a temperature sensor 3 is installed at the water outlet pipe 2 of the heating body, and the temperature sensor 3 is used to detect the temperature value on the water outlet pipe 2, which is compared with the preset rated temperature T, so as to know whether the water body is heated to the required temperature.

[0049] like Figure 1 , Figure 2 and Figure 4 As shown, Figure 2This is the schematic diagram of the circuit connection of temperature sensor 3. NTC1 is used to detect the outlet temperature T2, and NTC2 is used to detect the cavity temperature of the heating body. Temperature sensor 3 can adopt thermocouple sensor, JUMO steam temperature sensor, etc. If a thermocouple sensor is adopted, it can be used in steam. If a JUMO steam temperature sensor is adopted, it can be used in a pressurized environment containing water vapor. It is suitable for sterilizers, pharmaceuticals, food industries and other fields. You can select it according to your needs.

[0050] The heating body continues to work with a constant heating power P until the water is heated to the rated temperature T. If the outlet temperature T2 is greater than the rated temperature T, the heating power P is reset to zero. If the outlet temperature T2 is less than the rated temperature T, the heating power P is activated to ensure that the water temperature reaches the rated temperature T. It should be noted that the constant heating power P is a relative concept. Due to different voltages in different regions, the heating power P varies according to different voltages.

[0051] As an implementation method of the present application, when the first scale detection is performed, the energy efficiency threshold η is initially set m , the heating power P is constant. When the water body passes through the heating body and the outlet temperature T2 reaches and remains constant at the rated temperature T, it indicates that the water body has been heated to the rated temperature T. According to the scale detection formula, when the flow rate V is constant, the energy efficiency ratio η of the heating body is calculated by the formula. The energy efficiency ratio η and the energy efficiency threshold η are used to calculate the energy efficiency ratio η. m By comparison, when the energy efficiency ratio η is higher than the energy efficiency threshold η m When , it indicates that the scale in the heating body is in a healthy state, and there is no need to treat the scale in the heating body. If the energy efficiency ratio η is lower than the energy efficiency threshold η m This indicates that the heater needs to be scale-warning treated at this time; the reason is that as scale accumulates in the heater, the cross-section S decreases, while the flow rate V remains constant, thereby reducing the water inlet flow rate Q of the heater.

[0052] In addition, a detection circuit can also be used to obtain the voltage U of the heating body. When the voltage U of the heating body is detected, in order to ensure a constant energy efficiency ratio η, the flow rate V and the voltage U are in a linear relationship. The voltage U is in a stable state with the mains. Therefore, the constant voltage U corresponds to a constant flow rate threshold V. m , the flow velocity V is affected by the cross section S and will gradually deviate from the flow velocity threshold V m , so the flow rate V is greater than the flow rate threshold V m When the heating element needs to be scaled, the flow rate V is constant at the flow rate threshold V m If the voltage U and flow rate threshold V under constant energy efficiency ratio η are obtained before leaving the factory, the heating element is working normally. m If the flow rate V exceeds the flow rate threshold V in the value table,m Constant range, indicating that there is scale on the heating element, and scale warning treatment is required. If the flow rate V is at the constant flow rate threshold V in the numerical table m If the scale is within the specified range, it indicates that the heater is working normally, so as to monitor the scale status of the heater to avoid the risk of overheating and explosion of the heater.

[0053] The above two detection methods can be used after the outlet temperature T2 rises to the rated temperature T and stabilizes for a period of time, and one or both of them can be used to detect the scaling condition of the heating body. If two of them are used, there is no requirement for the order of the two detection methods. If one of them detects scaling, a scaling warning can be directly issued to make the detection more accurate.

[0054] As an implementation mode of the present application, the flow rate of the heating body is adjusted by PID; the flow rate V is adjusted by PID, specifically:

[0055] Δu[t]=u[t]-u[t-1]

[0056] =K p [e[t]-e[t-1]]+K i e(t)+K d [e[t]-2e[t-1]+e[t-2]];

[0057] Among them, K p , K i , K d are proportional, integral and differential gains respectively, e[t] is the error between the current temperature and the rated temperature T, u[t] is the compensation amount of the heating body flow velocity, and Δu[t] is the difference in compensation amount of the heating body flow velocity at different times. When the energy efficiency ratio η is constant, there is scale in the heating body, which reduces the cross-section S. The flow velocity V of the pump body is adjusted by PID so that the water inlet flow Q can meet the requirements and ensure the constant energy efficiency ratio η.

[0058] As an embodiment of the present application, after the heating body completes heating, a second scale detection is performed. Specifically, the heating power P is set to zero, the outlet temperature T2 of the heating body is the rated temperature T, water is supplied to the heating body, and the flow rate of the heating body can be selected at any value, depending on the flow rate V. The present application preferably adopts a flow rate lower than the flow rate threshold V. m , so that the outlet temperature T2 is reduced from the rated temperature T to the intermediate temperature T h , the intermediate temperature T h At least greater than the boiling point of water, set and obtain the heating body from the rated temperature T to the intermediate temperature T h The threshold time t m and the time required t s , when t s Equal to t mor beyond t m When the scale warning treatment is required, it indicates that the heating element needs to be treated.

[0059] Specifically, the efficiency of the heating body transferring heat to the water body is constant, but is easily affected by the amount of scale in the heating body. The more scale there is, the lower the heat transfer efficiency of the heating body. Therefore, water is supplied to the heating body, and the heating body transfers heat to the water body and gradually reduces its temperature until the temperature drops to the intermediate temperature T h , record the time required t s The value of the required time t s With threshold time t m Comparison, threshold time t m In order for the scale content of the heating element to reach the minimum requirement for use, if the required time t s Greater than the threshold time t m , indicating that the heat transfer efficiency of the heating body is low, the heating body needs scale warning treatment; if the required time t s Less than the threshold time t m , indicating that the heating body can work normally, and the scale detection is ended or the heating body is ready to be turned on.

[0060] As an embodiment of the present application, in order to further improve the accuracy of the energy efficiency ratio η, the heat required to heat the water body to the rated temperature T is recorded as q, and q is expressed as:

[0061] q=q1+q2+q3;

[0062] Among them, q1 represents the heat required to heat the water to the boiling point; q2 represents the heat required to raise the temperature of steam from the boiling point to the rated temperature T; q3 represents the latent heat of evaporation of water into steam at the boiling point. In this application, the boiling point of water is calculated as 100°C under standard atmospheric pressure. The unit of t time is seconds. The density and specific heat capacity of water and steam are different. When calculating, it is necessary to pay attention to using different density values, that is, ρ1 is the density of water, c1 is the specific heat capacity of water, ρ2 is the density of steam, and c2 is the specific heat capacity of steam. They are fixed values ​​under standard atmospheric pressure and the calculation is not described in detail here.

[0063] The heat relationship required for q1 is:

[0064] q1=ρ1·V1·c1·ΔT1:

[0065] The heat relationship required for q2 is:

[0066] q2=ρ2·V2·c2·ΔT2:

[0067] According to the latent heat of 1g water evaporating into 100℃ steam at 100℃ is 2257J / g, we can get:

[0068] q3=2257·ρ1·V1;

[0069] Among them, ρ1 is the density of water, V1 is the volume of water, c1 is the specific heat of water, ΔT1 is the temperature difference from water to boiling point; ρ2 is the density of steam, V2 is the volume of steam, c2 is the specific heat of steam; ΔT2 is the temperature difference of steam from boiling point to the rated temperature T.

[0070] From the above, it can be seen that when the water body has reached the rated temperature T after time t, the energy efficiency ratio η can be obtained more accurately, specifically:

[0071]

[0072] Energy efficiency ratio η and energy efficiency threshold η m By comparison, when the energy efficiency ratio η is higher than the energy efficiency threshold η m When , it indicates that the scale in the heating body is in a healthy state, and there is no need to treat the scale in the heating body. If the energy efficiency ratio η is lower than the energy efficiency threshold η m When the heating element is , it indicates that the heating element needs to be treated with scale warning to ensure the service life of the heating element and avoid the risk of overheating and explosion of the heating element, such as the energy efficiency threshold η m Can be set to 70%.

[0073] like Figure 5 As shown, it should be noted that the two scale detection methods obtain the scale conditions at different times when the heating body is working, and the second scale detection does not require the heating body to be heated again for detection, which reduces energy consumption and can also avoid the need for the heating body to be heated to the rated power T before working, so as to avoid the situation where the user repeatedly turns it on and repeats the heating detection; in addition, when the water passes through the front half of the heating body, this part is in a heating state and has a large scale content, while the back half of the heating body is water vapor and has a low scale content. Therefore, after normal operation, the heating power P is set to zero, and the room temperature water flushes the entire heating body. The heating body is cooled from the rated temperature T to the intermediate temperature T through a quantitative water flow. h When the room temperature water flushes the front half of the heating body, the water body and water vapor will drive the unattached scale particles to be discharged directly from the heating body as waste water. Then the flow velocity V of the heating body increases, further reducing the scale content in the front half of the heating body and improving the heat transfer efficiency of the heating body. The flow velocity V can be adjusted by the duty cycle.

[0074] The scale warning process includes at least one of a sound alarm, an information prompt and a scale treatment action. When the heating body is cleaned and then turned on again, if the heating body is turned on without being cleaned, the scale warning process is re-entered or the heating body is turned off, wherein the scale treatment action includes the heating body heating the water body to a dissolution temperature, dissolving the descaling agent at the dissolution temperature, and flowing the warm water dissolved with the descaling agent to the heating body to dissolve the scale in the heating area in the flow channel of the heating body.

[0075] Specifically, the sound alarm can be issued in the form of a buzzer, and a message prompt that scale treatment action needs to be performed can be displayed on the LCD screen to remind the user that scale treatment action is needed. When the user presses the corresponding button on the LCD screen, the scale treatment action can be performed. Before the scale treatment action, the user can add descaling agent into the water tank, which helps the scale to self-clean. During cleaning, the heating body heats the water body to 60°~70°, thereby increasing the dissolution rate of the descaling agent, which helps to dissolve the descaling agent in the heating body.

[0076] When the scale treatment action is completed, the sound alarm and information prompt are turned off, and the heating body is restarted. If the energy efficiency ratio η is within the energy efficiency threshold η m After that, the scale warning process is started again or the heating element is turned off and normal use is stopped. Specifically, after the scale treatment action is completed, the controller turns off the sound alarm and information prompt, and then the heating element heats the water body and performs the first scale detection. Within a cycle time t, the energy efficiency ratio η is still within the energy efficiency threshold η m Below, and / or within a cycle time t, the flow rate V is greater than the flow rate threshold V m , then the sound alarm and information prompt are turned on, indicating that the scale treatment action needs to be performed again. This process may be caused by not adding descaling agent. If the energy efficiency ratio η is still within the energy efficiency threshold η after at least one scale treatment action is completed m Below, set the cleaning time, such as 48h. If the scale treatment action has not been taken on the heating element, turn off the heating element or perform the scale warning treatment again, stop using the heating element, prevent the heating element from continuous dry burning operation, so as to avoid damage to the heating element; it indicates that it needs to be cleaned before normal use.

[0077] like Figure 3 and Figure 4 As shown, from Figure 3 Take the vertical line as the standard, the top to the bottom are the heating element outlet temperature T2, the duty cycle of the heating power P, the cavity temperature and the duty cycle of the flow rate V. Figure 4Take the vertical straight line as the standard, from the top to the bottom are the voltage U of the heating body, the outlet temperature T2 of the heating body, the duty cycle of the heating power P, the cavity temperature and the duty cycle of the flow rate V, where the flow rate V is precisely adjusted by the duty cycle. According to the attached figure, in the initial stage, the outlet temperature T2 rises and fluctuates at the rated temperature T. According to the error e[t] between the outlet temperature T2 and the rated temperature T at different times, the flow rate V is adjusted by PID, the heating power P is always in a constant state, and the cavity temperature of the heating body shows a slow upward trend. After the outlet temperature T2 reaches the rated temperature T, this part stabilizes for a period of time to complete the first scale detection, such as in Figure 3 or Figure 4 300s after the outlet temperature T2 reaches the rated temperature T, a cycle is randomly selected, such as 120s, to calculate the energy efficiency ratio η, and / or the constant energy efficiency ratio η, PID increases the flow rate V, and compares the adjusted flow rate V with the flow rate threshold V m Comparison; When the heating is completed and the second scale detection is required, the duty cycle of the heating power P is set to zero, the cavity temperature of the heating body gradually decreases, and the outlet temperature T2 decreases from the rated temperature T to the intermediate temperature T h After the second scale detection is completed, the heater is in a standby state, the duty cycle of the flow rate V is 100%, water is discharged from the heater, lowering the cavity temperature of the heater and washing away some unattached scale particles. This part of water is directly discharged and cannot be drunk.

[0078] in, Figure 3 This is a curve diagram of the heating element with scale. Figure 4 This is a curve diagram of a scale-free heating element. Figure 3 and Figure 4 The voltage U of the heating element is 229V. Figure 3 The curve of medium voltage U is not marked. In the absence of scale, the duty cycle of flow rate V is 48%. If there is scale, when the voltage of the heating body is 229V, the cross section S is reduced due to the influence of scale. In order to ensure the constant energy efficiency ratio η, PID is used to adjust the flow rate V so that the duty cycle of flow rate V is greater than 48%. If the duty cycle of flow rate V is greater than the scale setting value, it is judged that scale exists and scale warning processing is required; if the scale setting value is not reached, it indicates that the heating body is working normally. The scale setting value can be calculated by proportion. If the scale setting value is set between 48% and 68%, it is obvious that Figure 3 has exceeded that limit. In addition, Figure 3 If the outlet temperature T2 is higher than the rated temperature T, or the flow velocity V shows obvious oscillations, it can also prove the presence of scale.

[0079] A steam device includes a processor and a memory, wherein the memory can store a computer program on the processor; when the processor runs the computer program, the steps of the above method are executed. The processor may be an integrated circuit chip with signal processing capability. In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor or instructions in software form. The above processor may be a general-purpose processor, a digital signal processor, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The memory may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, etc.; the magnetic surface memory may be a disk memory or a tape memory. The volatile memory may be a random access memory, which is used as an external cache, such as a static random access memory, a synchronous static random access memory, a dynamic random access memory, etc., which will not be described one by one here.

[0080] like Figure 1 and Figure 2 As shown, when the steam device is used, a steam cabinet or a steamed bun machine can be used. NTC1 is a temperature sensor 3, which is used to monitor the temperature of the liquid outlet end of the heating body. NTC2 is another sensor, which is used to detect the temperature in the steam chamber of the steam cabinet or the steamed bun machine, and give a preset range for the steam chamber in advance, such as 140±10°C. The value detected by NTC1 is the outlet temperature T2 of the present invention.

[0081] A storage medium, wherein a computer program is stored in the storage medium, and when the computer program is executed by a processor, the steps of the above method are performed. The computer readable storage medium may be FRSM, ROM, PROM, EPROM, EEPROM, FlSsh Memory, etc. The computer device includes a memory with the above program and a processor for processing the computer program, so as to implement the above steps.

[0082] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for detecting scale on a heating element, characterized in that: The test method includes: Set the heating power P of the heating body, the rated temperature T of the water body, the water flow rate Q of the heating body, and the energy efficiency threshold η m , collect the heating time t, the inlet temperature T1 and the outlet temperature T2 of the heating body, and obtain the temperature difference ΔT between the inlet temperature T1 and the outlet temperature T2; wherein η is the energy efficiency ratio of the heating body, C is the specific heat capacity of the fluid; ρ is the density of the fluid; S is the cross-section of the water flowing through the heating body, V is the flow rate of the water flowing through the cross-section of the heating body, U is the voltage of the heating body, and R is the resistance of the heating body; The scale detection of the heating body is carried out at a constant heating power P. The scale detection formula is: When the outlet temperature T2 reaches and remains constant at the rated temperature T, the flow rate V is constant and the energy efficiency ratio η is at the energy efficiency threshold η m Below, it indicates that the heating body needs to be treated with scale warning; if the energy efficiency ratio is within the energy efficiency threshold η m The above indicates that the heating body works normally, or the energy efficiency ratio η is constant, the voltage U of the heating body is obtained, and the corresponding flow rate threshold V is set m , if the flow rate V is greater than the flow rate threshold V m When the flow rate V is constant at the flow rate threshold V m If the value is within 0.1, it indicates that the heater is working normally.

2. The scale detection method for a heating element according to claim 1, characterized in that: The flow rate V is regulated by PID, including: Δu[t]=u[t]-u[t-1] =K p [e[t]-e[t-1]]+K i e(t)+K d [e[t]-2e[t-1]+e[t-2]]; Among them, K p , K i , K d are the proportional, integral and differential gains respectively, e[t] is the error between the current temperature and the rated temperature T, and u[t] is the compensation amount of the flow rate V of the heating body.

3. The scale detection method for a heating element according to claim 1, characterized in that: When the heating body completes heating, the heating power P is set to zero, the outlet temperature T2 of the heating body is the rated temperature T, and water is supplied to the heating body to reduce the outlet temperature T2 from the rated temperature T to the intermediate temperature T h , the intermediate temperature T h At least greater than the boiling point of water, set and obtain the heating body from the rated temperature T to the intermediate temperature T h The threshold time t m and the time required t s , when t s Equal to t m or beyond t m When the scale warning treatment is required, it indicates that the heating element needs to be treated.

4. The scale detection method for a heating element according to claim 1, characterized in that: The heat required to heat the water to the rated temperature T is recorded as q. The rated temperature T is greater than the boiling point of the water. q is expressed as: q=q1+q2+q3; Among them, q1 represents the heat required to heat the water to the boiling point; q2 represents the heat required to heat the steam from the boiling point to the rated temperature T; q3 represents the latent heat of evaporation of the water into steam at the boiling point.

5. The scale detection method for a heating element according to claim 4, characterized in that: The heat relationship required for q1 is: q1=ρ1·V1·c1·ΔT1; The heat relationship required for q2 is: q2=ρ2·V2·c2·ΔT2; Among them, ρ1 is the density of water, V1 is the volume of water, c1 is the specific heat of water, ΔT1 is the temperature difference from water to boiling point; ρ2 is the density of steam, V2 is the volume of steam, c2 is the specific heat of steam; ΔT2 is the temperature difference of steam from boiling point to the rated temperature T.

6. The scale detection method for a heating body according to claim 1 or 3, characterized in that: The scale warning process includes at least one of a sound alarm, an information prompt and a scale treatment action. When the heating body is cleaned and then turned on again, if the heating body is turned on without being cleaned, the scale warning process is performed again or the heating body is turned off.

7. A steam device, characterized in that: The method comprises a processor and a memory, wherein the memory can store a computer program on the processor; when the processor runs the computer program, the processor executes the steps of the method according to any one of claims 1 to 6.

8. A storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are performed.

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