CN111912125B - Fluid heater and control method thereof - Google Patents
Fluid heater and control method thereof Download PDFInfo
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- CN111912125B CN111912125B CN202010957005.9A CN202010957005A CN111912125B CN 111912125 B CN111912125 B CN 111912125B CN 202010957005 A CN202010957005 A CN 202010957005A CN 111912125 B CN111912125 B CN 111912125B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H9/00—Details
- F24H9/20—Arrangement or mounting of control or safety devices
- F24H9/2007—Arrangement or mounting of control or safety devices for water heaters
- F24H9/2014—Arrangement or mounting of control or safety devices for water heaters using electrical energy supply
- F24H9/2028—Continuous-flow heaters
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
- F24H1/10—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium
- F24H1/101—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium using electric energy supply
- F24H1/102—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium using electric energy supply with resistance
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H9/00—Details
- F24H9/18—Arrangement or mounting of grates or heating means
- F24H9/1809—Arrangement or mounting of grates or heating means for water heaters
- F24H9/1818—Arrangement or mounting of electric heating means
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
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Abstract
The invention discloses a fluid heater and a control method thereof, comprising the following steps: the resistance heating body comprises a resistance wire; the resistance wire is provided with a heating resistance wire and a temperature control resistance wire, and the heating resistance wire comprises a thin resistance wire and a thick resistance wire; a fluid heating vessel comprising a body and a lid; a containing cavity is formed inside the main body and the cover body, a fluid inlet is formed in the cover body, and a fluid outlet is formed in the position, close to the cover body, of the main body; an electric control system including a heat-generating body temperature detection circuit; the resistance heating body is arranged in the accommodating cavity in the fluid heating container. The fluid heater and the control method thereof are convenient to use, the temperature of the heating element is sensed in real time by directly monitoring the change of the internal resistance of the resistance heating element, and the fluid temperature in close contact with the heating element is calculated; the structure of the fluid heater is simplified, and the stability of the outlet fluid temperature and the safety of the system are improved.
Description
Technical Field
The invention relates to the technical field of heating, in particular to a fluid heater and a control method thereof.
Background
The fluid heating technology is divided into several technologies, one is a heating method, one is a combustion method, but other methods can heat the fluid, but regarding environmental protection, although the two technologies can heat the fluid, the combustion method mainly utilizes flame to burn, and the flame can generate chemical substances such as methane and has harmful substances such as carbon monoxide and the like, so the environment is still damaged; the other heating method is relatively environment-friendly, toxic objects harmful to the environment cannot be generated, and when fluid passes through the heating device, harmful substances contained in the fluid can be catalyzed at high temperature to be decomposed into harmless substances, so that the advantage of environmental protection is achieved.
In the fluid heater at present, there are also the following problems:
1. a plurality of temperature sensors and flowmeters are required to be applied, the structure is complex, and the working efficiency is reduced;
2. the heating power is more lagged than the temperature change of the fluid, the fluid is difficult to be heated in time, and the temperature stability is not good.
Based on the above situation, the present invention provides a fluid heater and a control method thereof, which can effectively solve the above problems.
Disclosure of Invention
The invention aims to provide a fluid heater and a control method thereof. The fluid heater and the control method thereof are convenient to use, and the temperature of the heating element is sensed in real time by directly monitoring the change of the internal resistance of the resistance heating element, and the temperature of the fluid which is in close contact with the heating element is calculated. Because the system can monitor the internal temperature of the heating body once every few milliseconds, the fluid temperature at the next moment can be predicted before the fluid temperature changes, and the power output of the control system can be adjusted in advance. Even if no liquid exists in the heater, the heater can accurately and quickly judge under the condition of idle burning; the structure of the fluid heater is simplified, and the stability of the outlet fluid temperature and the safety of the system are improved.
The invention is realized by the following technical scheme:
a fluid heater comprising:
the resistance heating body comprises a resistance wire; the resistance wires comprise at least two groups of heating resistance wires with different powers and a group of temperature control resistance wires;
a fluid heating vessel comprising a body and a lid; a containing cavity is formed inside the main body and the cover body, a fluid inlet is formed in the cover body, and a fluid outlet is formed in the position, close to the cover body, of the main body;
an electric control system including a heat-generating body temperature detection circuit;
the resistance heating body is arranged in an accommodating cavity inside the fluid heating container, and the electric control system is electrically connected with the resistance heating body and the fluid heating container respectively.
The invention aims to provide a fluid heater and a control method thereof. The fluid heater and the control method thereof are convenient to use, and the temperature of the heating element is sensed in real time by directly monitoring the change of the internal resistance of the resistance heating element, and the temperature of the fluid which is in close contact with the heating element is calculated. Because the system can monitor the internal temperature of the heating body once every few milliseconds, the fluid temperature at the next moment can be predicted before the fluid temperature changes, and the power output of the control system can be adjusted in advance. Even if no liquid exists in the heater, the heater can accurately and quickly judge under the condition of idle burning; the structure of the fluid heater is simplified, and the stability of the outlet fluid temperature and the safety of the system are improved.
Preferably, a temperature sensor is arranged on the fluid outlet and is electrically connected with the electrical control system.
Preferably, the main body and the cover body are detachably connected.
Preferably, the resistance heating body is a ceramic heating sheet or a ceramic heating tube.
Preferably, the ceramic heating tube is of a tubular structure and comprises a ceramic tube base body, a resistance wire and a ceramic insulating layer which are sequentially connected from inside to outside and are manufactured into a whole, and the ceramic insulating layer is fixedly connected with an annular flange.
Preferably, the ceramic heating sheet comprises a first ceramic sheet, a resistance wire and a second ceramic sheet which are sequentially connected and manufactured into a whole.
Preferably, the distance between the temperature control resistance wire and the heating resistance wire is larger than 3 mm.
Preferably, the heating element temperature detection circuit comprises a reference resistor Rref, one end of the reference resistor Rref is connected with power voltage, the other end of the reference resistor Rref is electrically connected with one end of the temperature control resistance wire, and the other end of the temperature control resistance wire is grounded.
Preferably, the heating resistance wire comprises a thin resistance wire and a thick resistance wire, the thin resistance wire and the thick resistance wire are arranged in parallel, and the sectional area of the thick resistance wire is 1.5-3 times that of the thin resistance wire.
According to another aspect of the present invention, there is provided a control method of a fluid heater according to any one of claims 1 to 5, comprising: the method comprises the following steps:
step S1: presetting a target set temperature Td of the fluid in the electrical control system 3;
step S2: the actual temperature T of the resistance heating body is obtained by measuring the resistance value on the temperature control resistance wire, and the specific formula is as follows:
U＝Vref*(R/(R+Rref))；
T＝T0+((U*Rref)/(Vref-U)-R0)/(R0*TCR)；
wherein T0 is a reference temperature point, R0 is a resistance value measured at the reference temperature, Vref is a reference voltage added to the measurement circuit, Rref is a reference resistance, TCR is a temperature resistance coefficient;
step S3: calculating the fluid temperature T1 according to the actual temperature T of the resistance heating element, or directly measuring the fluid temperature T1 through a temperature sensor;
step S31: if the method for calculating the fluid temperature T1 according to the actual temperature T of the resistance heating element comprises the following specific steps:
step S311: by experimental means, e.g. a water heater with a total power of 1600W, the initial temperature of the flowing water is Th
Step S312: if the fixed output heating power is 100W, respectively controlling the flow rates to be 50ml, 100ml and 150ml until the fluid temperature Tl reaches 1000ml and the actual temperature T of the heating element;
step S313: if the fixed output heating power is 200W, respectively controlling the flow rates to be 50ml, 100ml and 150ml until the fluid temperature Tl reaches 1000ml and the actual temperature T of the heating element;
step S314: repeatedly measuring the fluid temperature Tl and the actual temperature T of the heating element at different flow rates when the fixed output heating power is increased by 100W;
step S315: the measured data are collated, and a mathematical method is used for solving a relational formula of Tl and T and a relational formula of flow F and T, wherein the specific formula is as follows;
Tl＝f1(T,Th,P)；
F＝f2(T,Th,P)；
wherein Th is the initial temperature of flowing water when not heating, P is the heating power, and f1 and f2 are two different analytical functions;
step S4: controlling the heating time on the resistance heating element according to the temperature T of the resistance heating element measured on the temperature control resistance wire or the measured temperature T1 of the temperature sensor, controlling the power output, making the temperature of the resistance heating element and the fluid not exceed the limit value, controlling the temperature of the fluid at a constant target temperature, and calculating the output power of the heater according to the following formula:
P＝Kp*(Tl-Td)+Ki*∫(Tl-Td)+Kd*d(Tl-Td)/dt
wherein, P is the current output power, Kp is a proportionality coefficient, Ki is an integral coefficient, Kd is a differential coefficient, Tl is the current fluid temperature, and Td is the target set temperature of the fluid;
step S41: if the heating power is less than or equal to 1/3 of the total power, only the thin resistance wire is controlled, and the electrifying duty ratio of the thin resistance wire is controlled according to the power requirement;
step S42: if the total power of 1/3 is not more than the total power of 2/3, the thin resistance wires and the thick resistance wires are conducted alternately in a time-sharing manner;
step S43: when the heating power is larger than or equal to 2/3 of the total power, the thin resistance wire is always electrified to generate heat, and the electrifying duty ratio of the thick heating wire is adjusted according to the actual requirement.
Compared with the prior art, the invention has the following advantages and beneficial effects:
the invention aims to provide a fluid heater and a control method thereof. The fluid heater and the control method thereof are convenient to use, and the temperature of the heating element is sensed in real time by directly monitoring the change of the internal resistance of the resistance heating element, and the temperature of the fluid which is in close contact with the heating element is calculated. Because the system can monitor the internal temperature of the heating body once every few milliseconds, the fluid temperature at the next moment can be predicted before the fluid temperature changes, and the power output of the control system can be adjusted in advance. Even if no liquid exists in the heater, the heater can accurately and quickly judge under the condition of idle burning; the structure of the fluid heater is simplified, and the stability of the outlet fluid temperature and the safety of the system are improved.
1. The invention simplifies the traditional measuring system consisting of one inlet temperature sensor, two outlet temperature sensors and one flowmeter into one outlet temperature sensor. In the occasion with low temperature precision requirement, even an external outlet temperature sensor is not needed, and the temperature control requirement and the safety requirement of use can be met only by the temperature feedback of the heating element;
2. the temperature control resistance wire is added on the resistance heating element, so that the temperature change of the heating element can be monitored more quickly and directly, the change of the fluid temperature and the actual flow can be calculated, the heating power can be adjusted before the temperature change of the fluid, the stability of the fluid temperature is improved, and the reaction time of temperature safety control is also prolonged.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic diagram of the structure of the present invention (from another perspective);
FIG. 3 is a schematic view of the structure of the present invention (when unassembled);
FIG. 4 is a schematic circuit diagram of a circuit for detecting a temperature of a heating element according to the present invention;
FIG. 5 is a schematic structural view of a ceramic heating tube according to the present invention;
FIG. 6 is a schematic cross-sectional view of a ceramic heating tube according to the present invention;
FIG. 7 is a schematic cross-sectional view of the ceramic heating sheet according to the present invention;
FIG. 8 is a schematic structural view of the resistance wire of the present invention.
Detailed Description
In order that those skilled in the art will better understand the technical solutions of the present invention, the following description of the preferred embodiments of the present invention is provided in conjunction with specific examples, but it should be understood that the drawings are for illustrative purposes only and should not be construed as limiting the patent; for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the present patent.
Example 1:
as shown in fig. 1 to 3, the present invention provides a fluid heater including:
the resistance heating body 1 comprises a resistance wire 11; the resistance wires 11 comprise at least two groups of heating resistance wires 111 with different powers and a group of temperature control resistance wires 112; the temperature control resistance wire 112 is added, so that the temperature change of the resistance heating body 1 can be monitored more quickly and directly, the change of the fluid temperature and the actual flow can be calculated, and the heating power can be adjusted before the fluid temperature changes.
A fluid heating container 2 including a body 21 and a lid 22; a containing cavity is formed inside the main body 21 and the cover 22, a fluid inlet 221 is arranged on the cover 22, and a fluid outlet 211 is arranged at the position of the main body 21 close to the cover 22; fluid enters the fluid heating container 2 from the fluid inlet 221 to be heated, and then flows out from the fluid outlet 211 after being heated.
The electric control system 3 and the electric appliance control system 3 can be a single chip microcomputer or a PLC controller and the like. The electric control system 3 includes a heating element temperature detection circuit 31; the heating element temperature detection circuit 31 is used for detecting the resistance value of the temperature control resistance wire 112, so as to calculate the actual temperature T of the resistance heating element 1.
The resistance heating element 1 is arranged in an accommodating cavity inside the fluid heating container 2, and the electric control system 3 is respectively electrically connected with the resistance heating element 1 and the fluid heating container 2. The electric control system controls the working conditions of the resistance heating body 1 and the fluid heating container 2.
According to another aspect of the present invention, there is provided a control method of a fluid heater according to any one of claims 1 to 5, comprising: the method comprises the following steps:
step S1: presetting a target set temperature Td of the fluid in the electrical control system 3;
step S2: the actual temperature T of the resistance heating element 1 is obtained by measuring the resistance value of the temperature control resistance wire 112, and the specific formula is as follows:
U＝Vref*(R/(R+Rref))；
T＝T0+((U*Rref)/(Vref-U)-R0)/(R0*TCR)；
wherein T0 is a reference temperature point, R0 is a resistance value measured at the reference temperature, Vref is a reference voltage added to the measurement circuit, Rref is a reference resistance, TCR is a temperature resistance coefficient;
step S3: calculating a fluid temperature T1 from the actual temperature T of the resistance heating element 1, or directly measuring a fluid temperature T1 by a temperature sensor;
step S31: the method for calculating the fluid temperature T1 from the actual temperature T of the resistance heating element 1 comprises the following steps:
step S311: using experimental methods, such as a 1600W total heater, the initial temperature of the flowing water is Th;
step S312: if the fixed output heating power is 100W, respectively controlling the flow rates to be 50ml, 100ml and 150ml until the fluid temperature Tl reaches 1000ml and the actual temperature T of the resistance heating element 1;
step S313: if the fixed output heating power is 200W, respectively controlling the flow rates to be 50ml, 100ml and 150ml until the fluid temperature Tl reaches 1000ml and the actual temperature T of the resistance heating element 1;
step S314: repeatedly measuring the fluid temperature Tl and the actual temperature T of the resistance heating element 1 at different flow rates when the fixed output heating power is increased by 100W;
step S315: the measured data are collated, and a mathematical method is used for solving a relational formula of Tl and T and a relational formula of flow F and T, wherein the specific formula is as follows;
Tl＝f1(T,Th,P)；
F＝f2(T,Th,P)；
wherein Th is the initial temperature of flowing water when not heating, P is the heating power, and f1 and f2 are two different analytical functions;
step S4: according to the temperature T of the resistance heating element 1 measured on the temperature control resistance wire 111 or the measured temperature T1 of the temperature sensor, the length of the heating time on the resistance heating element 1 is controlled, the power output is controlled, the temperature of the resistance heating element 1 and the temperature of the fluid do not exceed a limit value, the temperature of the fluid is controlled at a constant target temperature, and the calculation formula of the output power of the heater is as follows:
P＝Kp*(Tl-Td)+Ki*∫(Tl-Td)+Kd*d(Tl-Td)/dt
wherein, P is the current output power, Kp is a proportionality coefficient, Ki is an integral coefficient, Kd is a differential coefficient, Tl is the current fluid temperature, and Td is the target set temperature of the fluid;
in order to enable relevant EMC indexes to meet the requirements of regulatory standards such as CCC, CE and the like under the condition of high-power temperature-control power-regulation heating, when the total power of the resistance heating element 1 is between 1200W and 2200W, the resistance heating element 1 is divided into 1 according to the power: 2, two parts with the same common end; when the total power of the resistance heating element 1 is between 2000W and 4000W, the resistance heating element 1 is divided into 1: 2: 4, three parts with the same common end can be divided into 1: 1: 2 or 1: 2: 2, three parts; when the total power of the resistance heating body 1 is between 3500W-8000W, the resistance heating body 1 is divided into 1: 2: 4: 8, four parts with the same common end.
Step S41: if the heating power is less than or equal to 1/3 of the total power, only controlling the thin resistance wire 1111, and controlling the electrifying duty ratio of the thin resistance wire according to the power requirement;
step S42: if the total power 1/3 is less than or equal to the total power 2/3, the thin resistance wire 1111 and the thick resistance wire 1112 are alternately conducted in a time-sharing manner;
step S43: when the heating power is larger than or equal to 2/3 of the total power, the thin resistance wire 1111 is always electrified to generate heat, and the electrifying duty ratio of the thick heating wire 1112 is adjusted according to actual needs.
By the control method, the current harmonic and voltage flicker values in the EMC indexes can be suppressed to be minimum, and the requirements of relevant regulations are met. By analogy, under the condition that the heating element is divided into three or four sections, current harmonic waves and voltage flicker components can be restrained by using similar algorithms.
Example 2:
as shown in fig. 1 to 3, the present invention provides a fluid heater including:
the resistance heating body 1 comprises a resistance wire 11; the resistance wires 11 comprise at least two groups of heating resistance wires 111 with different powers and a group of temperature control resistance wires 112; the temperature control resistance wire 112 is added, so that the temperature change of the resistance heating body 1 can be monitored more quickly and directly, the change of the fluid temperature and the actual flow can be calculated, and the heating power can be adjusted before the fluid temperature changes.
A fluid heating container 2 including a body 21 and a lid 22; a containing cavity is formed inside the main body 21 and the cover 22, a fluid inlet 221 is arranged on the cover 22, and a fluid outlet 211 is arranged at the position of the main body 21 close to the cover 22; fluid enters the fluid heating container 2 from the fluid inlet 221 to be heated, and then flows out from the fluid outlet 211 after being heated.
The electric control system 3 and the electric appliance control system 3 can be a single chip microcomputer or a PLC controller and the like. The electric control system 3 includes a heating element temperature detection circuit 31; the heating element temperature detection circuit 31 is used for detecting the resistance value of the temperature control resistance wire 112, so as to calculate the actual temperature T of the resistance heating element 1.
The resistance heating element 1 is arranged in an accommodating cavity inside the fluid heating container 2, and the electric control system 3 is respectively electrically connected with the resistance heating element 1 and the fluid heating container 2. The electric control system controls the working conditions of the resistance heating body 1 and the fluid heating container 2.
Further, in another embodiment, a temperature sensor is disposed on the fluid outlet 211, and the temperature sensor is electrically connected to the electrical control system 3.
The temperature sensor is arranged to measure the temperature of the fluid, so that the output power of the heater can be calculated conveniently.
Further, in another embodiment, the main body 21 and the cover 22 are detachably connected.
Because the connection can be dismantled, if resistance heat-generating body 1 breaks down, can in time change, the later maintenance of being convenient for.
Further, in another embodiment, the resistance heating body 1 is a ceramic heating sheet 5 or a ceramic heating tube 4.
Further, in another embodiment, the ceramic heating tube 4 is a tubular structure, and includes a ceramic tube base 41, a resistance wire 11 and a ceramic insulating layer 43 which are connected in sequence from inside to outside and made into an integral body, and an annular flange 44 is fixedly connected to the ceramic insulating layer 43. The resistance wire 11 is printed on the ceramic tube base body 41 or the ceramic insulation layer 43.
The ceramic heating tube 4 is of a hollow structure, so that the contact area between the ceramic heating tube and fluid is increased, the inside and the outside can be in contact with the fluid, and the heating efficiency of the heater is enhanced.
Further, in another embodiment, the ceramic heating sheet 5 includes a first ceramic sheet 51, a resistance wire 11 and a second ceramic sheet 53 which are connected in sequence and made into a whole. The resistance wire 11 is printed between the first ceramic plate 51 and the second ceramic plate 53.
The ceramic heating sheet 5 is provided with a resistance wire between two ceramic sheets, and has a larger contact area with fluid and good heating efficiency.
Further, in another embodiment, the distance between the temperature-controlled resistance wire 112 and the heating resistance wire 111 is greater than 3 mm.
The temperature-controlled resistance wire 112 and the heating resistance wire 111 need to keep an effective electrical insulation distance to ensure that the two work normally.
Further, in another embodiment, the heating element temperature detection circuit 31 includes a reference resistor Rref312, one end of the reference resistor Rref312 is connected to the power voltage, the other end is electrically connected to one end of the temperature-controlled resistance wire 112, and the other end of the temperature-controlled resistance wire 112 is grounded.
Further, in another embodiment, the heating resistance wire 111 comprises a thin resistance wire 1111 and a thick resistance wire 1112, the thin resistance wire 1111 and the thick resistance wire 1112 are arranged in parallel, and the sectional area of the thick resistance wire 1112 is 1.5-3 times that of the thin resistance wire 1111.
According to another aspect of the present invention, there is provided a control method of a fluid heater according to any one of claims 1 to 5, comprising: the method comprises the following steps:
step S1: presetting a target set temperature Td of the fluid in the electrical control system 3;
step S2: the actual temperature T of the resistance heating element 1 is obtained by measuring the resistance value of the temperature control resistance wire 112, and the specific formula is as follows:
U＝Vref*(R/(R+Rref))；
T＝T0+((U*Rref)/(Vref-U)-R0)/(R0*TCR)；
wherein T0 is a reference temperature point, R0 is a resistance value measured at the reference temperature, Vref is a reference voltage added to the measurement circuit, Rref is a reference resistance, TCR is a temperature resistance coefficient;
step S3: calculating a fluid temperature T1 from the actual temperature T of the resistance heating element 1, or directly measuring a fluid temperature T1 by a temperature sensor;
step S31: the method for calculating the fluid temperature T1 from the actual temperature T of the resistance heating element 1 comprises the following steps:
step S311: using experimental methods, such as a 1600W total heater, the initial temperature of the flowing water is Th;
step S312: if the fixed output heating power is 100W, respectively controlling the flow rates to be 50ml, 100ml and 150ml until the fluid temperature Tl reaches 1000ml and the actual temperature T of the resistance heating element 1;
step S313: if the fixed output heating power is 200W, respectively controlling the flow rates to be 50ml, 100ml and 150ml until the fluid temperature Tl reaches 1000ml and the actual temperature T of the resistance heating element 1;
step S314: repeatedly measuring the fluid temperature Tl and the actual temperature T of the resistance heating element 1 at different flow rates when the fixed output heating power is increased by 100W;
step S315: the measured data are collated, and a mathematical method is used for solving a relational formula of Tl and T and a relational formula of flow F and T, wherein the specific formula is as follows;
Tl＝f1(T,Th,P)；
F＝f2(T,Th,P)；
wherein Th is the initial temperature of flowing water when not heating, P is the heating power, and f1 and f2 are two different analytical functions;
step S4: according to the temperature T of the resistance heating element 1 measured on the temperature control resistance wire 111 or the measured temperature T1 of the temperature sensor, the length of the heating time on the resistance heating element 1 is controlled, the power output is controlled, the temperature of the resistance heating element 1 and the temperature of the fluid do not exceed a limit value, the temperature of the fluid is controlled at a constant target temperature, and the calculation formula of the output power of the heater is as follows:
P＝Kp*(Tl-Td)+Ki*∫(Tl-Td)+Kd*d(Tl-Td)/dt
wherein, P is the current output power, Kp is a proportionality coefficient, Ki is an integral coefficient, Kd is a differential coefficient, Tl is the current fluid temperature, and Td is the target set temperature of the fluid;
in order to enable relevant EMC indexes to meet the requirements of regulatory standards such as CCC, CE and the like under the condition of high-power temperature-control power-regulation heating, when the total power of the resistance heating element 1 is between 1200W and 2200W, the resistance heating element 1 is divided into 1 according to the power: 2, a thin resistance wire 1111 and a thick resistance wire 1112 at the same common end are arranged; when the total power of the resistance heating element 1 is between 2000W and 4000W, the resistance heating element 1 is divided into 1: 2: 4, three groups of heating resistance wires with the same common end can be divided into 1 when the power is smaller: 1: 2 or 1: 2: 2 three groups of heating resistance wires; when the total power of the resistance heating body 1 is between 3500W-8000W, the resistance heating body 1 is divided into 1: 2: 4: and 8, four groups of heating resistance wires with the same common end are arranged.
Step S41: if the heating power is less than or equal to 1/3 of the total power, only controlling the thin resistance wire 1111, and controlling the electrifying duty ratio of the thin resistance wire according to the power requirement;
step S42: if the total power 1/3 is less than or equal to the total power 2/3, the thin resistance wire 1111 and the thick resistance wire 1112 are alternately conducted in a time-sharing manner;
step S43: when the heating power is larger than or equal to 2/3 of the total power, the thin resistance wire 1111 is always electrified to generate heat, and the electrifying duty ratio of the thick heating wire 1112 is adjusted according to actual needs.
By the control method, the current harmonic and voltage flicker values in the EMC indexes can be suppressed to be minimum, and the requirements of relevant regulations are met. By analogy, under the condition that the heating element is divided into three or four sections, current harmonic waves and voltage flicker components can be restrained by using similar algorithms.
The fluid heater and the control method thereof according to the present invention can be easily manufactured or used by those skilled in the art according to the description of the present invention and the accompanying drawings, and can produce the positive effects described in the present invention.
Unless otherwise specified, in the present invention, if there is an orientation or positional relationship indicated by terms of "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, rather than to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore, the terms describing orientation or positional relationship in the present invention are for illustrative purposes only, and should not be construed as limiting the present patent, specific meanings of the above terms can be understood by those of ordinary skill in the art in light of the specific circumstances in conjunction with the accompanying drawings.
Unless expressly stated or limited otherwise, the terms "disposed," "connected," and "connected" are used broadly and encompass, for example, being fixedly connected, detachably connected, or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.
Claims (9)
1. A fluid heater, comprising:
the resistance heating body (1) comprises a resistance wire (11); the resistance wires (11) comprise at least two groups of heating resistance wires (111) with different powers and a group of temperature control resistance wires (112);
a fluid heating container (2) comprising a main body (21) and a lid (22); a containing cavity is formed inside the main body (21) and the cover body (22), a fluid inlet (221) is formed in the cover body (22), and a fluid outlet (211) is formed in the position, close to the cover body (22), of the main body (21);
an electric control system (3), the electric control system (3) including a heating element temperature detection circuit (31);
the resistance heating body (1) is arranged in an accommodating cavity inside the fluid heating container (2), and the electric control system (3) is electrically connected with the resistance heating body (1) and the fluid heating container (2) respectively;
the control method of the fluid heater comprises the following steps:
step S1: presetting a target set temperature Td of the fluid in the electrical control system (3);
step S2: the actual temperature T of the resistance heating body (1) is obtained by measuring the resistance value on the temperature control resistance wire (112), and the specific formula is as follows:
U=Vref *(R/(R+Rref) )；
T= T0+((U* Rref)/ (Vref -U)-R0)/(R0*TCR)；
wherein, T0 is a reference temperature point, R0 is a resistance value measured at the reference temperature, Vref is a reference voltage added in the measuring circuit, Rref is a reference resistance, TCR is a temperature resistance coefficient, U is a real-time voltage measured at two ends of the temperature-controlled resistance wire, and R is a real-time resistance value of the temperature-controlled resistance wire;
step S3: calculating a fluid temperature T1 according to the actual temperature T of the resistance heating element (1), or directly measuring the fluid temperature T1 through a temperature sensor;
step S31: the method for calculating the fluid temperature T1 according to the actual temperature T of the resistance heating element (1) comprises the following specific steps:
step S311: using experimental methods, such as a 1600W total heater, the initial temperature of the flowing water is Th;
step S312: if the fixed output heating power =100W, respectively controlling the flow rates to be 50ml, 100ml and 150ml until the fluid temperature Tl reaches 1000ml and the actual temperature T of the resistance heating element (1);
step S313: if the fixed output heating power =200W, respectively controlling the flow rates to be 50ml, 100ml and 150ml until the fluid temperature Tl reaches 1000ml and the actual temperature T of the resistance heating element (1);
step S314: repeatedly measuring the fluid temperature Tl and the actual temperature T of the resistance heating element (1) under different flow rates when the fixed output heating power is increased by 100W;
step S315: the measured data are collated, and a mathematical method is used for solving a relational formula of Tl and T and a relational formula of flow F and T, wherein the specific formula is as follows;
Tl = f1(T, Th, P)；
F = f2(T, Th, P)；
wherein Th is the initial temperature of flowing water when not heating, P is the heating power, and f1 and f2 are two different analytical functions;
step S4: according to the temperature T of the resistance heating element (1) measured on the temperature control resistance wire (111) or the measured temperature T1 of the temperature sensor, the length of the heating time on the resistance heating element (1) is controlled, the power output is controlled, the temperature of the resistance heating element (1) and the temperature of the fluid do not exceed a limit value, the temperature of the fluid is controlled at a constant target temperature, and the calculation formula of the output power of the heater is as follows:
P = Kp*( Tl -Td)+Ki*∫(Tl -Td)+Kd*d(Tl -Td)/dt
wherein, P is the current output power, Kp is a proportionality coefficient, Ki is an integral coefficient, Kd is a differential coefficient, Tl is the current fluid temperature, and Td is the target set temperature of the fluid;
step S41: if the heating power is less than or equal to 1/3 of the total power, only the thin resistance wire (1111) is controlled, and the electrifying duty ratio of the thin resistance wire is controlled according to the power requirement;
step S42: if the total power 1/3 is less than or equal to the total power 2/3, the thin resistance wire (1111) and the thick resistance wire (1112) are alternately conducted in a time-sharing manner;
step S43: when the heating power is larger than or equal to 2/3 of the total power, the thin resistance wire (1111) is always electrified to generate heat, and the electrifying duty ratio of the thick heating wire (1112) is adjusted according to the actual requirement.
2. The fluid heater of claim 1, wherein: and a temperature sensor is arranged on the fluid outlet (211) and is electrically connected with the electric control system (3).
3. The fluid heater of claim 1, wherein: the main body (21) and the cover body (22) are detachably connected.
4. The fluid heater of claim 1, wherein: the resistance heating body (1) is a ceramic heating sheet (5) or a ceramic heating tube (4).
5. The fluid heater of claim 4, wherein: the ceramic heating tube (4) is of a tubular structure and comprises a ceramic tube base body (41), a resistance wire (11) and a ceramic insulating layer (43) which are sequentially connected from inside to outside and are manufactured into a whole, wherein an annular flange (44) is fixedly connected to the ceramic insulating layer (43).
6. The fluid heater of claim 4, wherein: the ceramic heating sheet (5) comprises a first ceramic sheet (51), a resistance wire (11) and a second ceramic sheet (53) which are sequentially connected and integrally manufactured.
7. The fluid heater of claim 1, wherein: the distance between the temperature control resistance wire (112) and the heating resistance wire (111) is larger than 3 mm.
8. The fluid heater of claim 1, wherein: the heating body temperature detection circuit (31) comprises a reference resistor Rref (312), one end of the reference resistor Rref (312) is connected with power voltage, the other end of the reference resistor Rref is electrically connected with one end of the temperature control resistance wire (112), and the other end of the temperature control resistance wire (112) is grounded.
9. The fluid heater of claim 1, wherein: the heating resistance wire (111) comprises a thin resistance wire (1111) and a thick resistance wire (1112), the thin resistance wire (1111) and the thick resistance wire (1112) are arranged in parallel, and the sectional area of the thick resistance wire (1112) is 1.5-3 times that of the thin resistance wire (1111).
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| CN202010957005.9A CN111912125B (en) | 2020-09-12 | 2020-09-12 | Fluid heater and control method thereof |
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| CN111912125B true CN111912125B (en) | 2022-04-08 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69024741D1 (en) * | 1989-10-17 | 1996-02-22 | Seiko Instr Inc | Method and device for thermal data recording on a data carrier |
| TWM283701U (en) * | 2005-05-20 | 2005-12-21 | Ping Liu | Improved circuit device for controlling temperature of soldering iron |
| CN104423401A (en) * | 2013-08-23 | 2015-03-18 | 美的集团股份有限公司 | Water dispenser and outgoing water temperature control method thereof |
| CN106455718A (en) * | 2014-06-14 | 2017-02-22 | 进化有限公司 | Electronic vaporizer having temperature sensing and limit |
| CN110268206A (en) * | 2017-02-06 | 2019-09-20 | 法雷奥热系统公司 | Electric heater unit, corresponding heating circuit and the method for managing temperature |
| CN213178816U (en) * | 2020-09-12 | 2021-05-11 | 畅和智能家居(嘉兴)有限公司 | Fluid heater |
-
2020
- 2020-09-12 CN CN202010957005.9A patent/CN111912125B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69024741D1 (en) * | 1989-10-17 | 1996-02-22 | Seiko Instr Inc | Method and device for thermal data recording on a data carrier |
| TWM283701U (en) * | 2005-05-20 | 2005-12-21 | Ping Liu | Improved circuit device for controlling temperature of soldering iron |
| CN104423401A (en) * | 2013-08-23 | 2015-03-18 | 美的集团股份有限公司 | Water dispenser and outgoing water temperature control method thereof |
| CN106455718A (en) * | 2014-06-14 | 2017-02-22 | 进化有限公司 | Electronic vaporizer having temperature sensing and limit |
| CN110268206A (en) * | 2017-02-06 | 2019-09-20 | 法雷奥热系统公司 | Electric heater unit, corresponding heating circuit and the method for managing temperature |
| CN213178816U (en) * | 2020-09-12 | 2021-05-11 | 畅和智能家居(嘉兴)有限公司 | Fluid heater |
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