Electric heating device and heating and ventilation system

Abstract

The invention discloses an electric heating device and a heating and ventilation system with the electric heating device, the electric heating device comprises a shell, a heating element and a temperature control part, a heating cavity and a containing cavity which are isolated from each other are formed in the shell, the heating element is arranged in the heating cavity, the temperature control part comprises a temperature controller and a temperature sensing pipe, the temperature controller is located in the containing cavity, and the temperature sensing pipe is arranged in the containing cavity. At least part of the temperature sensing pipe is located in the heating cavity, and at least the other part of the temperature sensing pipe is located in the containing cavity and connected with the temperature controller. The temperature control part and the shell of the electric heating equipment are connected into a whole, so that the temperature control part is small in structural arrangement difficulty and low in assembly difficulty; meanwhile, the temperature controller is located in the containing cavity formed by the shell and isolated from the outside, explosion caused by contact between leaked refrigerants and electric sparks generated by the temperature controller is avoided, and the use safety of the electric heating device and the heating and ventilation system is improved.

Description

Technical Field

[0001] The present application relates to the field of HVAC technology, and in particular to an electric heating device and a HVAC system equipped with the electric heating device. Background Art

[0002] Electric heating is widely used in heating, ventilation, air conditioning and other HVAC fields to supplement the heat of fluids and improve the heating effect. Electric heating can be used alone to heat gas, liquid and other fluids, and can also be used as auxiliary electric heating in the HVAC systems of air conditioners, multi-split units, heat pumps, water heaters, swimming pool machines and other equipment. In order to ensure the safety of water use and prevent the electric heating from continuously heating the water in its heating chamber when the temperature control fails, thereby causing problems such as excessive heating of the electric heating or bursting of its shell due to excessive pressure, electric heating is generally equipped with a temperature control unit.

[0003] In the related technologies, there are problems with the structural layout and assembly difficulties between electric heating and temperature control units. When a refrigerant leak occurs in a HVAC system using flammable refrigerants, the temperature control unit also has the risk of explosion, posing a major safety hazard. Summary of the invention

[0004] The main purpose of the present application is to provide an electric heating device and a HVAC system equipped with the electric heating device, aiming to solve the technical problems that the existing temperature control unit installation structure is difficult to arrange and there is a risk of explosion.

[0005] To achieve the above-mentioned purpose, the present application proposes an electric heating device, including a shell, a heating element and a temperature control unit, wherein a heating chamber and a receiving chamber are formed in isolation inside the shell, and the shell is provided with a water inlet and a water outlet connected to the heating chamber; the heating element is arranged in the heating chamber; the temperature control unit includes a thermostat and a temperature sensing tube, the thermostat is located in the receiving chamber, at least part of the temperature sensing tube is located in the heating chamber, and at least another part of the temperature sensing tube is located in the receiving chamber and connected to the thermostat. By connecting the temperature control unit with the shell of the electric heating device as a whole, the temperature control unit has low structural arrangement difficulty and low assembly difficulty; at the same time, the temperature controller is located in the receiving chamber formed by the shell and isolated from the outside world, so as to avoid the leakage of refrigerant and the electric spark generated by the temperature control unit to contact and cause explosion.

[0006] Preferably, the housing comprises a heating shell and a protective box connected to each other, the heating shell forms the heating cavity, the protective box forms the accommodating cavity, and the protective box is a sealed structure, so that the protective box can be easily disassembled and assembled while ensuring the sealing of the accommodating cavity.

[0007] Preferably, the protection box covers the heating shell and encloses the outer surface of the heating shell to form the accommodating cavity, so that a sealed accommodating cavity can be formed.

[0008] Preferably, the protection box is provided with a wire hole, and the thermostat is electrically connected to the external electric control box by passing a wire through the wire hole, so as to ensure the sealing of the wire when passing through the protection box, and prevent the refrigerant from entering the accommodating cavity.

[0009] Preferably, the heating shell is provided with a wiring terminal, at least part of which extends into the accommodating cavity, and the wiring terminal is electrically connected to the thermostat and the heating element. In this way, the connection point between the wiring terminal and the wire is designed to be located in the accommodating cavity to prevent electric sparks from being generated at the connection between the wiring terminal and the wire to ignite the refrigerant when the refrigerant leaks.

[0010] Preferably, a heat-conducting sleeve is provided in the heating chamber, and the heat-conducting sleeve has an open end connected to the heating shell and communicating with the accommodating chamber, and part of the temperature-sensing tube extends from the open end into the heat-conducting sleeve. In this way, the temperature-sensing tube can be kept substantially vertical only by the limitation of the heat-conducting sleeve, and the temperature-sensing tube has good stability, while ensuring the sealing of the heating shell.

[0011] Preferably, the portion of the temperature sensing tube located in the heat-conducting sleeve is formed with a temperature sensing probe, and the temperature sensing probe is arranged closer to the water outlet than the water inlet. This makes it easier for the temperature sensing probe to sense the water temperature at the higher temperature water outlet, thereby avoiding hysteresis in the operation of the temperature control unit.

[0012] Preferably, the electric heating device satisfies one or more of the following conditions: the heating element is one of a PTC heating plate, a metal heating tube and a PI heating film; the temperature sensing tube is one of a stainless steel tube, a copper tube and a titanium tube; the heating shell is a stainless steel heating shell; the protective box is one of an aluminum alloy protective box, a stainless steel protective box and an engineering plastic protective box.

[0013] Preferably, the temperature control unit is provided with two, including a first temperature control unit and a second temperature control unit, the first temperature control unit and the second temperature control unit are arranged in series; the first temperature control unit includes a first thermostat and a first temperature sensing tube, the first temperature control unit is configured as follows: when the temperature in the heating chamber is greater than a first preset temperature, the medium in the first temperature sensing tube drives the first thermostat to disconnect the power connection; when the temperature in the heating chamber is less than the first preset temperature, the medium in the first temperature sensing tube drives the first thermostat to restore the power connection; the second temperature control unit includes a second thermostat and a second temperature sensing tube, the second temperature control unit is configured as follows: when the temperature in the heating chamber is greater than a second preset temperature, the medium in the second temperature sensing tube drives the second thermostat to disconnect the power connection; the first preset temperature is less than the second preset temperature. Under normal circumstances, the safety of water use can be ensured only by the first temperature control unit, and the second thermostat is used to provide further protection when the first thermostat fails.

[0014] The present application also provides a HVAC system, comprising the electric heating device as described above.

[0015] Based on the electric heating device and HVAC system of the embodiment of the present application, a accommodating chamber isolated from the heating chamber is provided in the shell, and the temperature controller is arranged in the accommodating chamber, so that the temperature control unit is connected to the shell as an integral whole, and the temperature control unit has low structural arrangement difficulty and low assembly difficulty; at the same time, the temperature controller is located in the accommodating chamber formed by the shell and is isolated from the outside world, thereby avoiding explosion caused by electric sparks generated by the refrigerant and the temperature control unit when a refrigerant leak occurs in the HVAC system, thereby further improving the safety of the electric heating device and the HVAC system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0017] Figure 1 It is a partial schematic diagram of the existing HVAC system;

[0018] Figure 2 This is a schematic diagram of the three-dimensional structure of an electric heating device according to an embodiment of the present application;

[0019] Figure 3 This is a schematic diagram of the disassembled structure of an electric heating device according to an embodiment of the present application;

[0020] Figure 4 for Figure 3 A schematic diagram of the structure of the electric heating device in another direction.

[0021] Description of Figure Numbers:

[0022] 100-electric heating device; 10-shell; 11-heating shell; 111-heating chamber; 112-water inlet; 113-water outlet; 114-exhaust port; 115-heat-conducting sleeve; 1151-open end; 12-protection box; 121-accommodating chamber; 122-wire hole; 20-heating element; 21-wiring terminal; 30-temperature control unit; 31-temperature controller; 32-temperature sensing tube; 321-capillary part; 322-temperature sensing probe; 30A-first temperature control unit; 31A-first temperature controller; 32A-first temperature sensing tube; 30B-second temperature control unit; 31B-second temperature controller; 32B-second temperature sensing tube; 210-electric control box; 220-refrigerant tube; 230-heat exchanger; 240-water pump; 250-energy storage water tank. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0024] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0025] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0026] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0027] In addition, the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0028] The present application proposes an electric heating device 100 and a HVAC system.

[0029] It should be noted that HVAC system equipment includes but is not limited to air conditioners, multi-split units, heat pumps, water heaters, swimming pool machines, etc. Taking HVAC equipment with refrigerant as the heating medium and water as the heating object as the example, the HVAC system of the HVAC equipment may include an indoor unit installed indoors for heating water and an outdoor unit that may be installed outdoors and perform heat exchange with the external environment. Figure 1 This is a partial schematic diagram of the HVAC system of this HVAC equipment. Please refer to Figure 1 The indoor unit may include a water circulation flow path and a refrigerant pipe 220. Refrigerant flows in the refrigerant pipe 220. The refrigerant is preferably a new type of flammable refrigerant such as R32 and R290, which has the advantages of high thermal conductivity, large latent heat of evaporation, good fluidity, low delivery pressure, etc. The indoor unit heats the water by exchanging heat between the refrigerant in the refrigerant pipe 220 and the water in the water circulation flow path, thereby outputting water at a set temperature.

[0030] Specifically, the indoor unit may further include components such as a heat exchanger 230, a water pump 240, an electric heating device 100, and an energy storage water tank 250. The heat exchanger 230, the electric heating device 100, the energy storage water tank 250, and the water pump 240 are connected by water pipes to form a water circulation flow path. The heat exchanger 230 has two inlets and two outlets, one set of interconnected inlets and outlets is for the refrigerant pipe 220 to pass through, and the other set of interconnected inlets and outlets is for the water medium to pass through. When the water medium flows through the heat exchanger 230, the refrigerant pipe 220 in the heat exchanger 230 contacts the water, and the refrigerant in the refrigerant pipe 220 dissipates heat to heat the water in the heat exchanger 230. The water pump 240 provides power for the water circulation flow. The electric heating device 100 can be arranged between the heat exchanger 230 and the energy storage water tank 250, that is, the water heated by the heat exchanger 230 is reheated in the electric heating device 100 and enters the energy storage water tank 250 through the water pipe. The electric heating device 100 plays an auxiliary role in the heat supply of the heat exchanger 230 in a low temperature environment, so that the water temperature of the energy storage water tank 250 is increased under the action of the electric heating device 100, achieving a better heating effect and improving the energy efficiency of the unit. The energy storage water tank 250 is used to store or transport water of a set temperature into an external device, which can be a floor heating pipe or a user's domestic water pipe, etc., to meet the user's heating needs.

[0031] The outdoor unit may include components such as an evaporator, a compressor, and an expansion valve. The evaporator, the compressor, the heat exchanger 230, and the expansion valve are connected in a loop in sequence through the refrigerant pipe 220. When the HVAC equipment is working, the refrigerant in the evaporator absorbs heat from the air, and the refrigerant changes from a low-temperature and low-pressure gas to a high-temperature and low-pressure gas; then the high-temperature gas is compressed by the compressor, so that the refrigerant forms a high-temperature and high-pressure liquid; the high-temperature and high-pressure liquid exchanges heat with the water in the water circulation flow path through the heat exchanger 230, so that the water temperature in the water circulation flow path increases, and the refrigerant becomes a low-temperature and high-pressure liquid; the low-temperature and high-pressure liquid is converted into a low-temperature and low-pressure gas through the expansion valve, and then circulates to the evaporator again, thus completing the refrigerant circulation process.

[0032] In addition, the indoor unit also includes a body and an electric control box 210. Components such as a heat exchanger 230, an electric heating device 100, an energy storage water tank 250, and water pipes can be arranged in the body, and the body is placed indoors, so that the water circulation flow path has a certain cold-proof function, ensuring that the water in the water pipe has a good circulation effect. The electric control box 210 is also arranged in the body of the indoor unit. The electric control box 210 is integrated with a power supply system and a control system for supplying power and controlling the operation of various electrical components of the indoor unit, and is convenient for centralized setting and maintenance of the circuits, circuit boards and control components in the electric control box 210. A control panel electrically connected to the electric control box 210 can also be provided on the body, so that the user can set parameters and control the working mode of the indoor unit by operating the control panel indoors.

[0033] During the invention and creation process of the present application, the inventor discovered that when electric heating is applied to a HVAC system, the temperature control unit is often connected to the electric control box of the HVAC system. Taking a mechanical temperature control unit as an example, the mechanical temperature control unit includes a thermostat and a temperature sensing tube. The thermostat is generally arranged in the electric control box of the HVAC system to facilitate the integrated connection and control of the entire circuit. One end of the temperature sensing tube is inserted into the heating cavity of the electric auxiliary heating, and the other end is inserted into the electric control box and connected to the thermostat. Because there is a certain distance between the electric control box and the electric heating, and the temperature sensing tube is a hard metal tube, the electric control box needs to reserve a sufficiently large opening for the temperature sensing tube to be inserted at different angles to reduce the difficulty of assembly, and the sealing difficulty of the electric control box is extremely high. In this way, the structural arrangement difficulty of inserting one end of the temperature sensing tube into the shell of the electric heating and the other end into the electric control box is large, the assembly difficulty is high, and the temperature control unit has a certain explosion risk when the refrigerant leaks. The electric heating device 100 and the HVAC system equipped with the electric heating device 100 provided in the present application are intended to solve the technical problems that the existing temperature control unit installation structure is difficult to arrange and has the risk of explosion.

[0034] See also Figures 2 to 4 An electric heating device 100 according to an embodiment of the present application includes a housing 10 , a heating element 20 and a temperature control unit 30 .

[0035] Specifically, a heating chamber 111 and a receiving chamber 121 are formed inside the housing 10, and the heating chamber 111 is used to contain water, and the receiving chamber 121 is used to provide protection for the temperature control unit 30. The heating element 20 is arranged in the heating chamber 111, and is used to heat the water in the heating chamber 111 for use. The housing 10 is provided with a water inlet 112 and a water outlet 113 connected to the heating chamber 111, and the water inlet 112 and the water outlet 113 respectively provide channels for water to enter and exit the heating chamber 111. Water enters the heating chamber 111 through the water inlet 112 and is heated by the heating element 20 during the process of flowing in the heating chamber 111, and finally flows out through the water outlet 113.

[0036] The temperature control unit 30 includes a temperature controller 31 and a temperature sensing tube 32. The temperature controller 31 is located in the accommodating chamber 121, at least part of the temperature sensing tube 32 is located in the heating chamber 111, and at least another part of the temperature sensing tube 32 is located in the accommodating chamber 121 and connected to the temperature controller 31. The temperature control unit 30 is preferably a mechanical temperature control unit, which is used to provide a physical power-off means, and has higher stability and reliability than electric control or sensor control means. Among them, the thermostat 31 is used to cut off the power circuit of the heating element 20, and the temperature sensing tube 32 partially extends into the heating chamber 111 to sense the water temperature in the heating chamber 111. The temperature sensing tube 32 is filled with a temperature sensing medium. As the water temperature in the heating chamber 111 rises, the medium pressure in the temperature sensing tube 32 changes. When it exceeds a certain value, the mechanical structure inside the thermostat 31 is triggered to disconnect, thereby cutting off the power circuit of the electric heating device 100, avoiding the problem of the shell 10 bursting due to excessive pressure or the heating element 20 continuously heating and causing energy waste due to the evaporation of a large amount of water due to excessive water temperature, thereby improving the safety of the use of the electric heating device 100. The thermostat 31 is located in the accommodating chamber 121, which can isolate the thermostat 31 from the outside world, so that the electric spark that may be generated at the connection point between the thermostat 31 and the wire is generated in the accommodating chamber 121. When the refrigerant leaks in the HVAC system, the refrigerant has no contact with the electric spark, thereby avoiding the electric spark from igniting the flammable refrigerant, further improving the safety of the use of the electric heating device 100.

[0037] In the technical solution of the present application, the electric heating device 100 can be used alone to heat the fluid, and the temperature control unit 30 greatly improves the safety of the electric heating device 100. By forming a heating chamber 111 and a receiving chamber 121 separated from each other inside the shell 10, the temperature controller 31 is arranged in the receiving chamber 121, so that the temperature control unit 30 is connected to the shell 10 as a whole, and the temperature control unit 30 has low structural arrangement difficulty and low assembly difficulty. The electric heating device 100 can also be used in a HVAC system for auxiliary heating. Compared with the structure in which the temperature controller 31 is arranged in the external electric control box 210 in the related art, one end of the temperature sensing tube 32 is inserted into the heating chamber 111 and the other end is inserted into the electric control box 210, it can be deduced that the electric control box 210 does not need to be provided with an opening for inserting the temperature sensing tube 32, so that the electric control box 210 can be set as a sealed structure. When the components of the HVAC system are powered on, the sparks generated by the terminals of the components in the electric control box 210 are isolated by the electric control box 210. When the electric heating device 100 is powered on, the sparks generated by the terminals of the thermostat 31 are isolated by the shell 10. As a result, when a refrigerant leaks in the HVAC system, the refrigerant and the sparks have no contact, thereby preventing the sparks from igniting the flammable refrigerant, thereby improving the safety of the electric heating device 100 and the HVAC system having the electric heating device 100.

[0038] In some embodiments, the housing 10 may include a heating shell 11 and a protection box 12 connected to each other. The heating shell 11 forms the above-mentioned heating chamber 111, and the protection box 12 forms the above-mentioned accommodating chamber 121. The protection box 12 is a sealed structure, which has the effect of isolating the refrigerant. The protection box 12 and the heating shell 11 can be connected by bolt connection, welding, clamping, etc., preferably by bolt connection, which is convenient for disassembling the protection box 12 to inspect or replace the thermostat 31 in the accommodating chamber 121. By fixing the protection box 12 on the heating shell 11, the thermostat 31 located in the accommodating chamber 121 is adjacent to the installation position of the heating shell 11, and most of the temperature sensing tube 32 connected to the thermostat 31 can extend to the heating chamber 111, which can more accurately reflect the water temperature in the heating chamber 111, and then control the on and off of the thermostat 31 according to the water temperature.

[0039] Preferably, the material of the heating shell 11 is iron or iron alloy, and more preferably a stainless steel heating shell 11, which has low cost, high strength, and is not easy to rust.

[0040] Preferably, the material of the protection box 12 can be fireproof and explosion-proof materials such as stainless steel and engineering plastics, and more preferably the protection box 12 is made of aluminum alloy, which has the advantages of high strength, low density, good hardness, good plasticity, and better explosion-proof performance.

[0041] Preferably, the heating element 20 can be a PTC heating sheet, a metal heating tube, a PI heating film or other types of heating elements 20, more preferably a heating sheet or heating tube made of PTC material, which has a large positive temperature coefficient and can improve the heating efficiency of the electric heating device 100, thereby improving the heating efficiency of the HVAC system. There is no restriction on the number and arrangement of the heating elements 20 in the heating chamber 111. When the heating sheet is selected, it can be attached to the inner wall of the heating shell 11; when the heating tube is selected, it can be distributed in the heating chamber 111 in the form of straight tubes or curved tubes.

[0042] In some embodiments, the heating shell 11 may be a closed cylindrical structure, and a hollow heating chamber 111 is formed in the heating shell 11. The cross-section of the cylindrical structure may be square, circular or irregular, etc., and the present application does not limit this. The water inlet 112 and the water outlet 113 may be arranged on the side or both ends of the heating shell 11, preferably distributed on the side of the heating shell 11 up and down, and the water inlet 112 is located below the water outlet 113, so as to facilitate judging the water level in the heating chamber 111 by the water outlet 113 located above. For example, when water flows out of the water outlet 113, it means that the amount of water in the heating chamber 111 meets the requirements for immersing the heating element 20. At this time, the heating element 20 can be powered on to heat the water, thereby avoiding local or overall dry burning damage to the heating element 20.

[0043] The protection box 12 can be connected to any position of the heating shell 11. For example, for the heating shell 11 with a cylindrical structure, the protection box 12 can be arranged on the side or both ends of the heating shell 11. In some embodiments, the protection box 12 can be a cover-type structure, for example, a rectangular box body with one side open. The protection box 12 covers the end of the heating shell 11 and encloses the outer surface of the heating shell 11 to form a receiving cavity 121. The thermostat 31 can be fixedly connected to the heating shell 11 or to the side wall of the protection box 12 by screwing, bonding, clamping, etc., so as to fix the thermostat 31 and prevent the shaking of the thermostat 31 from affecting the connection stability between it and the temperature sensing tube 32. Alternatively, one side of the protection box 12 that is open can be set to fit with the arc-shaped side of the heating shell 11. The protection box 12 covers a local position of the side of the heating shell 11 and encloses the outer surface of the heating shell 11 to form a receiving cavity 121.

[0044] Of course, in other embodiments, the protection box 12 can also be a fully enclosed box structure, the aforementioned accommodating cavity 121 is formed in the protection box 12, and an outer side surface of the protection box 12 is fixedly connected to the side surface or both ends of the heating shell 11. The thermostat 31 can be fixedly connected to the inner wall of the protection box 12 by screwing, bonding, clamping, etc., which can also achieve the effect of isolating the accommodating cavity 121 from the outside world.

[0045] See also Figure 3 and Figure 4 In the embodiment shown, the heating shell 11 is a cylindrical structure, and the heating element 20 is selected as a heating tube and is fixedly arranged on the inner wall of the bottom end of the heating shell 11, so that the heating tube can be extended in the heating chamber 111 along the length direction of the heating shell 11 to fully heat the water in the heating chamber 111, and at the same time, the water in the heating chamber 111 can completely immerse the heating tube, thereby reducing the probability of dry burning of the heating tube.

[0046] In the illustrated embodiment, the protection box 12 is a cylindrical box body with an open top. The protection box 12 is sealed and connected to the bottom of the heating shell 11 by bolts. This position setting facilitates the electrical connection between the thermostat 31 and the heating element 20.

[0047] In the illustrated embodiment, the thermostat 31 is connected to the protective box 12 by bolts, and the temperature sensing tube 32 passes through the bottom end of the heating shell 11 and partially extends into the heating chamber 111. In this way, the temperature sensing tube 32 is extended from bottom to top in the heating chamber 111, so that water enters the heating chamber 111 and accumulates at the bottom of the heating chamber 111 under the action of gravity and can immediately contact the temperature sensing tube 32, thereby avoiding the situation where the temperature sensing tube 32 cannot monitor the water temperature due to less water.

[0048] In the illustrated embodiment, the water inlet 112 and the water outlet 113 are both arranged on the side of the heating shell 11 and the water inlet 112 is located below the water outlet 113. Preferably, the water inlet 112 and the water outlet 113 are both provided with pipe joints, and the two pipe joints are respectively connected to the water inlet 112 and the water outlet 113 and fixed on the heating shell 11, so as to facilitate the connection of the electric heating device 100 with other components of the HVAC system through water pipes.

[0049] In the illustrated embodiment, an exhaust port 114 is provided at the top of the heating shell 11, and the exhaust port 114 is used to connect an exhaust valve externally. Because the water in the heating chamber 111 will generate water vapor during the heating process, excessive water vapor will increase the air pressure in the heating shell 11, which will affect the normal inflow and outflow of water in the heating shell 11 on the one hand, and will cause the liquid level in the heating chamber 11 to drop on the other hand. By providing the exhaust port 114 and connecting an exhaust valve externally, when the water vapor gas in the heating shell 11 reaches a certain pressure, the exhaust valve opens, and the water vapor leaks out of the heating shell 11 at the exhaust valve, thereby reducing the space occupied by the water vapor in the heating shell 11, so that the water in the heating shell 11 can reach a liquid level that meets the requirements.

[0050] It should be noted that the present application only takes a preferred embodiment shown in the figure as an example. Under the guidance of the aforementioned embodiments, the heating element 20, the protection box 12, the air inlet and the exhaust port 114 can also be arranged at other positions of the heating shell 11 without interfering with each other. The heating shell 11, the protection box 12 and the heating element 20 can also be selected as other structural forms, all of which belong to the protection scope of the present application.

[0051] It can be understood that in the embodiment of the present application, the electric heating device 100 can be applied to the HVAC system, and the power supply and power size of the heating element 20 need to be controlled by the electric control box 210 of the HVAC system. At the same time, in order to realize the function of disconnecting or connecting the power supply line of the heating element 20 by the thermostat 31, the thermostat 31 and the heating element 20 are connected in series to the same circuit and both are electrically connected to the electric control box 210. Specifically, the heating element 20 can be electrically connected to the thermostat 31 through a wire (not shown in the figure), and the thermostat 31 can be electrically connected to the electric control box 210 through a wire (not shown in the figure).

[0052] In some embodiments, in order to maintain the sealing of the accommodating chamber 121, a wire hole 122 is provided on the protection box 12 in the electrical connection structure between the thermostat 31 and the electric control box 210, and the thermostat 31 is electrically connected to the electric control box 210 in the HVAC system by passing a wire through the wire hole 122. In this way, the sealing of the wire when passing through the protection box 12 can be ensured to prevent the refrigerant from entering the accommodating chamber 121.

[0053] In some embodiments, in order to prevent the electric spark generated at the connection between the heating element 20 and the wire from being exposed to the outside world, the heating shell 11 is provided with a wiring terminal 21 on the electrical connection structure between the heating element 20 and the thermostat 31, and at least part of the wiring terminal 21 extends into the accommodating cavity 121, and the wiring terminal 21 electrically connects the thermostat 31 and the heating element 20. Specifically, the wiring terminal 21 can be fixedly arranged on the side wall of the heating shell 11, one end of which is electrically connected to the heating element 20, such as plug-in or welding connection, and the other end passes through the heating shell 11 and extends into the accommodating cavity 121 to be electrically connected to the thermostat 31, such as through a wire connection, thereby achieving conduction between the heating element 20 and the thermostat 31. The wiring terminal 21 can be fixed to the heating shell 11 by means of inlaying, bonding, etc., which, on the one hand, fixes the heating element 20 in the heating shell 11, and on the other hand, provides a contact position for the electrical connection of the heating element 20. By designing the connection point between the terminal 21 and the wire to be located within the accommodating chamber 121, the terminal 21 and the thermostat 31 are located close to each other, which facilitates the layout and connection of the wires, and the accommodating chamber 121 is isolated from the outside world to prevent electric sparks from being generated at the connection between the terminal 21 and the wire to ignite the refrigerant when the refrigerant leaks.

[0054] In some embodiments, a heat-conducting sleeve 115 is provided in the heating chamber 111, and the heat-conducting sleeve 115 has an open end 1151 connected to the heating shell 11 and communicating with the accommodating chamber 121, and a portion of the temperature-sensing tube 32 extends from the open end 1151 into the heat-conducting sleeve 115. The diameter of the heat-conducting sleeve 115 can be set to be slightly larger than the diameter of the temperature-sensing tube 32, so that the temperature-sensing tube 32 can be smoothly inserted without being tilted too much. At this time, the temperature-sensing tube 32 can be kept generally vertical only by the limitation of the heat-conducting sleeve 115, without the need for other fixing structures.

[0055] The heat-conducting sleeve 115 is preferably made of a metal material with a high thermal conductivity. One end of the heat-conducting sleeve 115 connected to the heating shell 11 is an open end 1151, which can be connected and fixed to the heating shell 11 by welding. The other end of the heat-conducting sleeve 115 is a closed end, so that the water in the heating chamber 111 cannot enter the heat-conducting sleeve 115. Compared with the solution of drilling a hole in the heating shell 11 and directly inserting the temperature sensing tube 32, it prevents the water vapor in the heating chamber 111 from entering the accommodating chamber 121 through the gap between the temperature sensing tube 32 and the hole, thereby damaging the thermostat 31, while maintaining the sealing of the heating shell 11. When the water temperature in the heating chamber 111 rises, the heat-conducting sleeve 115 and the air inside it can be quickly heated to a temperature close to or even reaching the temperature of the water in the heating chamber 111, and the temperature sensing tube 32 can sense the water temperature more accurately, avoiding the hysteresis of the operation of the thermostat 31.

[0056] Furthermore, the portion of the temperature sensing tube 32 located in the heat-conducting sleeve 115 is formed with a temperature sensing probe 322, and the temperature sensing probe 322 is arranged closer to the water outlet 113 than the water inlet 112. The temperature sensing tube 32 includes a capillary portion 321 and a temperature sensing probe 322, and the two ends of the capillary portion 321 are respectively connected to the temperature sensing probe 322 and the thermostat 31. The temperature sensing probe 322 has a larger internal cavity and contains more fluid medium. When the external temperature changes, the thermal expansion and contraction of the fluid medium changes more obviously. The capillary portion 321 has a smaller cross-section, and when the fluid medium undergoes thermal expansion and contraction, it is more sensitive to the push of the ejector rod inside the thermostat 31, so that the temperature sensing tube 32 can accurately sense the water temperature. Water flows from the water inlet 112 to the water outlet 113 in the heating chamber 111 and gradually heats up. The water temperature near the water inlet 112 is lower, and the water temperature near the water outlet 113 is higher. By setting the temperature sensing probe 322 closer to the water outlet 113, it is convenient to sense the water temperature at the water outlet 113 with a higher temperature, so as to promptly judge the situation of excessive water temperature and trigger the thermostat 31 to disconnect, so as to avoid the hysteresis of the temperature control unit 30 and delay the power-off timing, causing greater economic losses.

[0057] Preferably, the temperature control unit 30 is a gas temperature-sensing temperature control unit 30, and the temperature sensing tube 32 is filled with temperature-sensing gas. As the temperature rises, the pressure change in the temperature sensing tube 32 can trigger the disconnection of the mechanical structure inside the temperature controller 31. The temperature sensing tube 32 can be made of a metal material with high thermal conductivity such as stainless steel, copper and titanium, preferably a copper tube, which has the characteristics of good thermal conductivity and strong corrosion resistance, and can increase the service life of the temperature sensing tube 32 and reduce the frequency and cost of its maintenance and replacement.

[0058] Please read further Figure 4 In some embodiments, the temperature control unit 30 may be provided with two, including a first temperature control unit 30A and a second temperature control unit 30B, the first temperature control unit 30A and the second temperature control unit 30B are arranged in series, the first temperature control unit 30A includes a first thermostat 31A and a first temperature sensing tube 32A, and the second temperature control unit 30B includes a second thermostat 31B and a second temperature sensing tube 32B. The first temperature control unit 30A is configured as follows: when the temperature in the heating chamber 111 is greater than the first preset temperature, the medium in the first temperature sensing tube 32A drives the first thermostat 31A to disconnect the power connection; when the temperature in the heating chamber 111 is less than the first preset temperature, the medium in the first temperature sensing tube 32A drives the first thermostat 31A to restore the power connection; the second temperature control unit 30B is configured as follows: when the temperature in the heating chamber 111 is greater than the second preset temperature, the medium in the second temperature sensing tube 32B drives the second thermostat 31B to disconnect the power connection; the first preset temperature is less than the second preset temperature.

[0059] The first temperature control unit 30A and the second temperature control unit 30B are connected in series, and both can disconnect the power circuit of the electric heating device 100. Under normal conditions, the safety of water use can be ensured only by the first temperature control unit 30A. When the temperature in the heating chamber 111 is greater than the first preset temperature, the first temperature controller 31A is disconnected, and when the temperature in the heating chamber 111 is less than the first preset temperature, the first temperature controller 31A is restored to close. When the first temperature controller 31A is adhered or damaged and cannot disconnect the circuit, the second temperature control unit 30B can provide further protection. When the water in the heating chamber 111 is continuously heated to exceed the first preset temperature and reach the second preset temperature, the second temperature controller 31B is disconnected. The second temperature controller 31B is not provided with an elastic element that can be restored to close, that is, when the water in the heating chamber 111 is less than the second preset temperature, the second temperature controller 31B is still in a disconnected state. At this time, the line connection of the second temperature controller 31B needs to be manually restored to prevent the heating element 20 from restarting and causing safety hazards. The preset temperature of the temperature control unit 30 can be designed according to the pushing distance of the top rod inside the temperature controller 31 by the fluid medium in the temperature sensing tube 32 at different temperatures. The temperature range of the second preset temperature higher than the first preset temperature is preferably 5-10°C, which prevents the electric heating device 100 from overheating and avoids misjudgment of the second temperature control unit 30B.

[0060] On the other hand, the present application also proposes a HVAC system, including the electric heating device 100 of the above embodiment. Since the HVAC system adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here. By setting the electric heating device 100 as described in the above embodiment, the internal electric control box 210 of the HVAC system does not need to be provided with an opening for inserting the temperature sensing tube 32, so that the electric control box 210 can be set as a sealed structure to prevent the refrigerant from entering the electric control box 210 and exploding when leaking, thereby improving the safety of the HVAC system.

[0061] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. All equivalent structural changes made based on the concept of the present application and the contents of the present application description and drawings, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. An electric heating device, characterized in that: include: A shell (10) is formed with a heating chamber (111) and a receiving chamber (121) which are isolated from each other, and the shell (10) is provided with a water inlet (112) and a water outlet (113) which are in communication with the heating chamber (111); a heating element (20) disposed in the heating chamber (111); and A temperature control unit (30) comprises a temperature controller (31) and a temperature sensing tube (32), wherein the temperature controller (31) is located in the accommodating chamber (121), at least a portion of the temperature sensing tube (32) is located in the heating chamber (111), and at least another portion of the temperature sensing tube (32) is located in the accommodating chamber (121) and connected to the temperature controller (31).

2. The electric heating device according to claim 1, characterized in that: The housing (10) comprises a heating shell (11) and a protective box (12) which are connected to each other; the heating shell (11) forms the heating cavity (111); the protective box (12) forms the accommodating cavity (121); and the protective box (12) is a sealed structure.

3. The electric heating device according to claim 2, characterized in that: The protection box (12) covers the heating shell (11) and is enclosed with the outer surface of the heating shell (11) to form the accommodating cavity (121).

4. The electric heating device according to claim 2, characterized in that: The protection box (12) is provided with a wire hole (122), and the temperature controller (31) is electrically connected to an external electric control box by passing a wire through the wire hole (122).

5. The electric heating device according to claim 2, characterized in that: The heating shell (11) is provided with a wiring terminal (21), at least a portion of the wiring terminal (21) extends into the accommodating cavity (121), and the wiring terminal (21) is electrically connected to the temperature controller (31) and the heating element (20).

6. The electric heating device according to claim 2, characterized in that: A heat-conducting sleeve (115) is provided in the heating chamber (111), and the heat-conducting sleeve (115) has an open end (1151) connected to the heating shell (11) and communicating with the accommodating chamber (121), and a portion of the temperature sensing tube (32) extends from the open end (1151) into the heat-conducting sleeve (115).

7. The electric heating device according to claim 6, characterized in that: The portion of the temperature sensing tube (32) located inside the heat-conducting sleeve (115) is formed with a temperature sensing probe (322), and the temperature sensing probe (322) is arranged closer to the water outlet (113) than to the water inlet (112).

8. The electric heating device according to claim 2, characterized in that: Meet one or more of the following conditions: The heating element (20) is one of a PTC heating sheet, a metal heating tube and a PI heating film; The temperature sensing tube (32) is one of a stainless steel tube, a copper tube and a titanium tube; The heating shell (11) is a stainless steel heating shell; The protection box (12) is one of an aluminum alloy protection box, a stainless steel protection box and an engineering plastic protection box.

9. The electric heating device according to any one of claims 1 to 8, characterized in that: The temperature control unit (30) is provided with two, including a first temperature control unit (30A) and a second temperature control unit (30B), wherein the first temperature control unit (30A) and the second temperature control unit (30B) are arranged in series; The first temperature control unit (30A) comprises a first temperature controller (31A) and a first temperature sensing tube (32A), and the first temperature control unit (30A) is configured such that: when the temperature in the heating chamber (111) is greater than a first preset temperature, the medium in the first temperature sensing tube (32A) drives the first temperature controller (31A) to disconnect the power connection; when the temperature in the heating chamber (111) is less than the first preset temperature, the medium in the first temperature sensing tube (32A) drives the first temperature controller (31A) to restore the power connection; The second temperature control unit (30B) comprises a second temperature controller (31B) and a second temperature sensing tube (32B), and the second temperature control unit (30B) is configured such that: when the temperature in the heating chamber (111) is greater than a second preset temperature, the medium in the second temperature sensing tube (32B) drives the second temperature controller (31B) to disconnect the power supply; The first preset temperature is lower than the second preset temperature.

10. A HVAC system, characterized in that: It comprises the electric heating device as described in any one of claims 1 to 9.

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