Anti-freezing pipeline system for hot water coil of fresh air handling unit

Abstract

The utility model discloses an anti-freezing pipeline system for a hot water coil of a fresh air handling unit, the hot water coil is arranged in an air duct of the fresh air handling unit, and the anti-freezing pipeline system comprises a water inlet pipeline, a water return pipeline and a temperature sensor; a control valve is connected in series with the water inlet pipeline; the water return pipeline is connected in series with an electric valve; the circulating pipeline is connected with a circulating pump in series; according to the utility model, the temperature sensor, the control valve and the electric valve are matched to realize the automatic regulation and control of the flow of the heating medium, and the circulating pump and the check valve are matched to realize the reutilization of the heating medium, even if the heating medium injected from the outside is not uniformly distributed, due to the matching of the circulating pump and the check valve, the flow of the heating medium can be automatically regulated and controlled. The hot water in the hot water coil pipe flows fast, the temperature of the hot water coil pipe rises fast, and the hot water coil pipe does not lose temperature due to external low temperature, so that the air outlet temperature requirement is met as far as possible, the amount of hot water is enough during circulation, and the phenomenon of frost crack of the hot water coil pipe can be avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of air conditioning, in particular to an antifreeze pipeline system for a hot water coil of a fresh air air conditioning box. Background Art

[0002] The working principle of the fresh air conditioning box is to send the outdoor fresh air to the room after filtering, preheating, cooling and dehumidifying or humidifying, reheating and other functional sections of heat and humidity treatment, so as to meet the fresh air volume and maintain positive pressure requirements of personnel. When the outdoor temperature is low, the hot water coil of the fresh air conditioning box is prone to freezing and cracking, resulting in failure to operate normally, which in turn affects the production or living area it is responsible for, especially for precision production factories (such as constant temperature and humidity workshops), which will cause product defects and losses.

[0003] To address this problem, the current antifreeze technology for the hot water coil of the fresh air air conditioning box generally adopts preheating measures to prevent freezing, and the heat source is generally hot water, steam, etc. By monitoring the temperature behind the hot water coil, when the temperature is lower than the set value, the control cabinet adjusts the opening of the electric valve to increase the heat source supply, and vice versa, to prevent the water in the hot water coil from freezing and bursting the hot water coil. This antifreeze measure can generally meet the requirements, but there are still some problems in actual work, as follows:

[0004] When extreme working conditions occur outdoors, such as sudden heavy rain and snow, the outdoor temperature will drop sharply. Therefore, the air conditioning system needs to handle a large amount of fresh air, and the short-term demand for heat medium is large, that is, there is a phenomenon of supply exceeding demand. At this time, the system pipeline is prone to uneven hydraulic distribution (heat source water), or the heating system reacts slowly and the heat medium temperature rises slowly, which can easily cause some areas of the hot water coil in the fresh air air conditioning box to freeze and crack (because the current hot water coil uses heat source water directly, when there is a large degree of hot water demand in order for the hot water coil to reach the set temperature, because this demand is temporary, the amount of heat source water cannot quickly meet the demand, and the heat utilization of the direct heat source water is also low, resulting in a slow rise in the temperature of the hot water system. At the same time, the outside temperature drops relatively quickly, so some areas of the hot water coil, such as the hot water coil outlet where the temperature rises slowly, are prone to freezing and cracking under the influence of a large temperature difference), making the fresh air unit unable to operate normally.

[0005] Therefore, how to solve the above-mentioned deficiencies in the prior art has become a topic to be studied and solved in the present invention. Summary of the invention

[0006] The purpose of the utility model is to provide a fresh air air conditioning box hot water coil antifreeze piping system, aiming to solve the problem raised in the above background technology that since the current hot water coil uses the heat source water directly through and out, when there is a large degree of hot water demand, it is easy to cause uneven hydraulic distribution and cause the hot water coil to freeze and crack.

[0007] To achieve the above purpose, the technical solution adopted by the utility model is: a fresh air air conditioning box hot water coil antifreeze pipeline system, the air duct of the fresh air air conditioning box is provided with a hot water coil to adjust the air outlet temperature to a set temperature, and the antifreeze pipeline system includes a water inlet pipeline, a water return pipeline and a temperature sensor;

[0008] The water inlet pipeline has an inlet and an outlet, the inlet of the water inlet pipeline serves as an injection port for the heating medium, the outlet of the water inlet pipeline is connected to the inlet of the hot water coil, and a control valve is connected in series to the water inlet pipeline;

[0009] The return water pipeline has an inlet and an outlet, the inlet of the return water pipeline is connected to the outlet of the hot water coil, the outlet of the return water pipeline serves as a return port for the heating medium, and an electric valve is connected in series to the return water pipeline;

[0010] The temperature sensor is arranged in the fresh air air conditioning box and located at the air outlet side of the hot water coil, and is used to detect the temperature of the air after passing through the hot water coil;

[0011] The antifreeze pipeline system further includes a control circuit, which is electrically connected to the temperature sensor, the control valve and the electric valve;

[0012] It also includes a circulation pipeline, the two ends of which are respectively connected to the water inlet side and the water outlet side of the control valve, and a circulation pump is connected in series to the circulation pipeline;

[0013] A further technical solution also includes a check valve, the water inlet end of the check valve is connected to the outlet of the hot water coil, and the water outlet end of the check valve is connected to the water inlet side of the circulation pump; when the purpose of heating the hot water coil cannot be met by adjusting the heating medium to enter and discharge the hot water coil, through the above design, with the cooperation of the circulation pump and the check valve, the purpose of reusing the heating medium after the hot water coil is heated can be achieved, thereby utilizing the heating medium to a greater extent.

[0014] The control circuit is electrically connected to the circulation pump. Through the above design, on the basis of the coordinated cooperation of the temperature sensor, the control valve and the electric valve, the circulation pump and the check valve are further coordinated, so that the five components are all under the control of the same control circuit. It has a high degree of automation and a fast response speed, and can be suitable for extreme weather and normal seasonal weather.

[0015] The relevant contents of the above plan are explained as follows:

[0016] 1. The heating medium can be hot water, water vapor, or a gas-liquid mixture that can flow along a pipeline. When the heating medium flows to the hot water coil, the hot water coil can be heated. The inlet and the outlet represent the heating medium inlet and the heating medium outlet, respectively. The heating medium enters from the inlet and is discharged from the outlet to achieve the purpose of heating. The hot water coil can be made of a metal material with good heat absorption effect; the control circuit mainly plays a control role, so that the temperature sensor, the control valve and the electric valve can cooperate with each other, so that the heating medium can be used to a greater extent in the process of flowing in the hot water coil.

[0017] 2. Through the above design, the present application can realize the automatic regulation of the flow rate of the heating medium through the coordinated cooperation of the temperature sensor, the control valve and the electric valve, so that the flow rate of the heating medium can be controlled, which is convenient for the reasonable distribution of the heating medium, and there will be no phenomenon that the heating medium introduced is insufficient to meet the heating of the hot water coil due to the excessive discharge speed.

[0018] According to a further technical solution, a filter is connected in series on the water inlet side of the control valve on the water inlet pipeline to filter the heating medium passed in. Through the above design, the heating medium can be filtered to prevent one or more of the control valve, the circulation pump, the hot water coil, the electric valve and the check valve from being blocked.

[0019] A further technical solution is that the two ends of the filter are respectively connected in series with a first manual valve and a second manual valve. Since the heating medium is continuously passed into the hot water coil, after the filter has worked for a long time, there will be a phenomenon of filter residue accumulation. At this time, the heating medium can be prevented from flowing by closing the first manual valve and the second manual valve at the same time, so as to facilitate the cleaning or replacement of the filter.

[0020] A further technical solution is that a third manual valve and a fourth manual valve are respectively connected in series at both ends of the electric valve. Since the electric valve is used to control the discharge flow, it may have valve core damage and need to be repaired or replaced. Therefore, with this design, the heating medium at both ends of the electric valve can be sealed by closing the third manual valve and the fourth manual valve. At this time, the electric valve can be directly replaced or repaired.

[0021] A further technical solution also includes an emergency bypass, wherein both ends of the emergency bypass are respectively connected to the outlet of the third manual valve and the inlet of the fourth manual valve. A fifth manual valve is also connected in series on the emergency bypass. Since the heating medium needs to continuously flow into the hot water coil to maintain the temperature of the hot water coil, this means that in order to prevent the hot water coil from being damaged due to high pressure, the heating medium needs to be discharged. Therefore, this design allows the heating medium to be discharged through the emergency bypass when the electric valve is inspected and replaced.

[0022] The terms “first”, “second”, etc. used in this document do not specifically refer to an order or sequence, nor are they used to limit the present case. They are only used to distinguish components or operations described with the same technical terms.

[0023] As used herein, “connected” or “positioned” may refer to two or more components or devices being in direct physical contact with each other, or being in indirect physical contact with each other, or may refer to two or more components or devices operating or moving with each other.

[0024] The terms “include,” “including,” “have,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0025] The terms used in this document generally have the ordinary meaning of each term used in this field, in the context of the case and in the specific context, unless otherwise noted. Certain terms used to describe the present invention will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the present invention.

[0026] The terms "front", "back", "up", "down", "left", "right", etc. used in this article are all directional terms. In this case, they are only used to illustrate the positional relationship between the various structures, and are not used to limit the protection plan of this case and the specific direction during actual implementation.

[0027] The principles and advantages of this utility model are as follows:

[0028] 1. The utility model can realize the automatic flow control action of the heating medium through the coordinated cooperation of the temperature sensor, the control valve and the electric valve. Specifically, the temperature on the air outlet side of the hot water coil is first detected by the temperature sensor, and then fed back to the control circuit, and the control valve and the electric valve are controlled according to the size of the detected temperature and the set temperature. When the detected temperature is large, the opening of the control valve is reduced and the opening of the electric valve is increased. If the detected temperature is small, the opening of the control valve is increased and the opening of the electric valve is reduced. During the whole process, the control valve and the electric valve are changed in real time to maintain the temperature on the air outlet side of the hot water coil always greater than or equal to the set temperature.

[0029] 2-1. When the detected temperature is lower than the set temperature, the purpose of heating the hot water coil cannot be met by adjusting the amount of heating medium entering and discharging from the hot water coil. Therefore, the purpose of reusing the heating medium after the hot water coil is heated can be achieved through the cooperation of the circulation pump and the check valve, so as to utilize the heating medium to a greater extent and avoid the uneven hydraulic distribution due to the large short-term demand for heat medium. Specifically, when the detected temperature is lower than the set temperature, the circulation pump is controlled to open, the control valve is closed, and the opening of the electric valve is reduced at the same time, so that the water inlet pipe enters All water enters the hot water coil through the circulation pump (without passing through the control valve, that is, the inflow of the heating medium is no longer controlled). At the same time, the heating medium that has partially heated up the hot water coil passes through the check valve again and is injected into the hot water coil by the circulation pump. Even if the heating medium injected from the outside is unevenly distributed, due to the cooperation of the circulation pump and the check valve, the hot water in the hot water coil has a fast flow rate, and the hot water coil heats up quickly, and will not lose temperature quickly due to the low temperature outside, so as to meet the outlet air temperature requirements as much as possible. In addition, the amount of hot water is sufficient during circulation, which can avoid the phenomenon of freezing and cracking of the hot water coil.

[0030] 2-2. In the existing antifreeze technology solutions for the hot water coils of fresh air air conditioners, hot water preheating measures are generally used to prevent freezing. When the temperature drops sharply under extreme working conditions outdoors, the demand for the entire hot water system will fluctuate greatly (the hot water system includes a hot water supply pipe for providing hot water and a hot water return pipe for hot water return), especially when the hot water system is relatively large, especially in a system with many fresh air air conditioner equipment connected (the present application Figure 1The figure shows a hot water system connected to a fresh air air conditioning box device). When the demand for hot water changes suddenly, the water supply system will have varying degrees of delay in the response of the hot water supply and water supply temperature of the fresh air air conditioning box due to the long pipeline transmission distance and the time required to load the water pump and boiler. In addition, in response to the sudden drop in temperature, the control valves of the hot water coils of multiple fresh air air conditioning boxes will automatically increase their opening to obtain more hot water supply to protect their hot water coils from being frozen. In this case, it is inevitable to break the original hydraulic balance between the fresh air air conditioning box devices, and also aggravate the gap between the hot water flow and demand of some fresh air air conditioning box hot water coils. When the water supply and water supply temperature cannot meet the demand, the hot water coil will most likely be frozen and cracked (because the hot water flow rate is slower, and because the return pipe is connected last compared to the inlet pipe). The return water pipe is in contact with the heating medium, so the temperature of the inlet end of the return water pipe rises slowly. At the same time, the inlet end of the return water pipe is connected to the outlet end of the hot water coil. When the temperature difference fluctuates greatly, the inlet end of the return water pipe and the outlet end of the hot water coil are likely to be frozen and cracked due to the dual effects of slow temperature rise and slow flow rate. However, in most implementation schemes, the return water pipe is made of thicker seamless steel pipes and the hot water coil is made of thinner copper pipes. Therefore, when frozen and cracked, the outlet end of the hot water coil is often frozen and cracked first), which leads to the inability of the fresh air air conditioner to operate normally.

[0031] The antifreeze solution provided by this patent can start the circulation pump to perform a constant flow heat exchange cycle at the hot water coil when the outdoor temperature drops suddenly, thereby enhancing the heat exchange capacity of the hot water coil and effectively preventing the hot water coil from freezing and cracking due to low flow rate, slow flow velocity and rapid temperature drop. In addition, after starting the constant flow heat exchange cycle, the heat transfer between the hot water coil and the hot water supply main will be accelerated, which will help the hot water "respond" to the temperature rise rate after the sudden drop in ambient temperature, and speed up the time for the water supply temperature to reach a stable state, making the probability of the hot water coil being frozen and cracked smaller. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Attached Figure 1 The figure is a schematic diagram of the overall structure of the antifreeze piping system according to an embodiment of the utility model.

[0033] In the above attached figures: 1. Fresh air air conditioning box; 2. Hot water coil; 3. Temperature sensor; 4. Water inlet pipe; 5. Water return pipe; 6. Control valve; 7. Electric valve; 8. Circulation pipe; 9. Circulation pump; 10. Check valve; 11. Filter; 12. First manual valve; 13. Second manual valve; 14. Third manual valve; 15. Fourth manual valve; 16. Emergency bypass; 17. Fifth manual valve. DETAILED DESCRIPTION

[0034] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0035] Embodiment: The present invention will be clearly described below with diagrams and detailed descriptions. After understanding the embodiments of the present invention, any person skilled in the art can make changes and modifications based on the techniques taught by the present invention without departing from the spirit and scope of the present invention.

[0036] The terms used herein are only for describing specific embodiments and are not intended to be limiting of the present invention. Singular forms such as "a", "this", "here", "this" and "the" as used herein also include plural forms.

[0037] See attached Figure 1 As shown, a fresh air air conditioning box hot water coil antifreeze pipeline system, a fresh air air conditioning box 1 is provided with a hot water coil 2 in the air duct to adjust the outlet air temperature to a set temperature, and the antifreeze pipeline system includes a water inlet pipeline 4, a water return pipeline 5 and a temperature sensor 3;

[0038] The water inlet pipe 4 has an inlet and an outlet. The inlet of the water inlet pipe 4 serves as an injection port for the heating medium. The outlet of the water inlet pipe 4 is connected to the inlet of the hot water coil 2. A control valve 6 is connected in series to the water inlet pipe 4; (generally, the heating medium mainly refers to hot water or water vapor, and hot water is preferably used here).

[0039] The return water pipeline 5 has an inlet and an outlet. The inlet of the return water pipeline 5 is connected to the outlet of the hot water coil 2. The outlet of the return water pipeline 5 serves as a reflux port for the heating medium, that is, the outlet of the return water pipeline 5 is connected to an external reflux device for reflux of the heating medium after the heated hot water coil 2. An electric valve 7 is serially connected to the return water pipeline 5.

[0040] The temperature sensor 3 is arranged in the fresh air air conditioning box 1 and is located at the air outlet side of the hot water coil 2, and is used to detect the temperature of the air after passing through the hot water coil 2;

[0041] The antifreeze piping system also includes a control circuit, which is electrically connected to the temperature sensor 3, the control valve 6 and the electric valve 7, so as to control the outlet air temperature on the outlet side of the hot water coil 2 according to the real-time feedback from the temperature sensor 3, so that the control valve 6 and the electric valve 7 can work in coordination with each other, so that the flow rate of the heating medium in the hot water coil 2 meets the requirement of the outlet air temperature.

[0042] In some specific implementations, the specific structural design of the control circuit is not specifically limited here, as long as it plays the role of controlling the electric valve 7 and the control valve 6.

[0043] It should be noted that the reflux device connected to the return water pipe 5 can be a boiler, a heating water tank or a hot water return water pipe and the like. When a boiler or a heating water tank is selected, the inlet of the water inlet pipe 4 is also connected to the boiler or the heating water tank, so that the water is heated in the boiler or the heating water tank, and then the heated water enters the water inlet pipe 4 and then flows back to the boiler or the heating water tank from the return water pipe 5; if the return water pipe 5 is connected to a hot water return water pipe, the inlet of the water inlet pipe 4 is connected to the hot water supply pipe. In order to maximize the use of energy, multiple hot water coils 2 can be heated. Therefore, the hot water supply pipe and the hot water return pipe are preferably connected. In this way, the hot water supply pipe is connected to a heat source device, such as a boiler, and the hot water return pipe is also connected to the boiler. The hot water circulates in the hot water supply pipe and the hot water return pipe (the hot water supply pipe and the hot water return pipe circulate in Figure 1 (not shown in the figure, only the flow direction of the hot water is indicated by a closed hollow arrow). During the flow, multiple antifreeze pipeline systems will be introduced to heat the multiple hot water coils 2.

[0044] Generally, the set temperature is an interval value, which can be set to about 5 degrees here, and is preferably about 5 degrees, because the initial temperature requirement for the heating medium is not high at about 5 degrees, and the blown wind can also be made more comfortable.

[0045] The utility model can realize automatic control of the flow of the heating medium through the cooperation of the temperature sensor 3, the control valve 6 and the electric valve 7. Specifically, the temperature sensor 3 detects the temperature of the outlet side of the hot water coil 2 in real time and feeds it back to the control circuit, which controls the control valve 6 and the electric valve 7 according to the difference between the detected outlet temperature and the set temperature. Specifically, when the detected temperature is relatively high, the flow of the heating medium entering the hot water coil 2 is reduced and the discharge flow is increased by reducing the opening of the control valve 6 and increasing the opening of the electric valve 7, thereby gradually reducing the outlet temperature of the air heated by the hot water coil 2; if the detected temperature is relatively low, the flow of the heating medium entering the hot water coil 2 is increased and the discharge flow is reduced by increasing the opening of the control valve 6 and reducing the opening of the electric valve 7, thereby gradually increasing the outlet temperature of the air heated by the hot water coil 2. In the whole process, the control valve 6 and the electric valve 7 are controlled and adjusted in real time, and the temperature of the outlet side of the hot water coil 2 can be maintained in the set temperature range.

[0046] In some specific embodiments, a circulation pipeline 8 is further included, the two ends of which are respectively connected to the water inlet side and the water outlet side of the control valve 6, and a circulation pump 9 is connected in series to the circulation pipeline 8;

[0047] It also includes a check valve 10, the water inlet end of the check valve 10 is connected to the outlet of the hot water coil 2, and the water outlet end of the check valve 10 is connected to the water inlet side of the circulation pump 9; the control circuit is electrically connected to the circulation pump 9, and when the circulation pump 9 is turned on, the control valve 6 is closed.

[0048] When the detected temperature is lower than the set temperature, and the purpose of heating the hot water coil 2 cannot be met by adjusting the control valve 6 and the electric valve 7 at this time, in order to prevent the hot water coil 2 from freezing and cracking, the purpose of reusing the heating medium after heating the hot water coil 2 can be achieved through the cooperation of the circulation pump 9 and the check valve 10, so as to utilize the heating medium to a greater extent. Specifically, when the detected outlet air temperature is lower than the set temperature, at this time, the circulation pump 9 is controlled to be turned on, the control valve 6 is closed, and the opening of the electric valve 7 is reduced, so that all the water entering the water inlet pipeline 4 enters the hot water coil 2 through the circulation pump 9 (no longer flows through the control valve 6, that is, the inflow of the heating medium is no longer controlled), and at the same time, part of the heating medium flowing through the hot water coil 2 passes through the check valve 10 again and is injected into the hot water coil 2 through the circulation pump 9. At this time, the hot water in the hot water coil 2 has a fast flow rate and a sufficient amount of hot water during circulation, which can ensure that the outlet air temperature meets the requirements as much as possible, or at least prevent the hot water coil 2 from freezing and cracking.

[0049] In some specific embodiments, a filter 11 is serially connected to the water inlet pipeline 4 at the water inlet side of the control valve 6 to filter the introduced heating medium.

[0050] When the filter 11 is not involved in the work, the heating medium (i.e., hot water) will directly enter the control valve 6 and other components along the water inlet pipe 4. With the continuous input of hot water, impurities in the hot water (such as sand and dirt in the hot water supply pipe) enter these components, which will cause these components to become blocked. After the filter 11 is installed, once the hot water enters the water inlet pipe 4 along the hot water supply pipe, it will be filtered by the filter 11, thereby preventing one or more of the control valve 6, the circulating pump 9, the hot water coil 2, the electric valve 7 and the check valve 10 from being blocked.

[0051] In some specific embodiments, a first manual valve 12 and a second manual valve 13 are respectively connected in series at both ends of the filter 11 .

[0052] Since the heating medium is continuously passed into the hot water coil 2, in order to prevent the presence of impurities in the heating medium, which may cause accumulation of filter residues in the filter 11 after long-term operation, the heating medium flow can be shut off by closing the first manual valve 12 and the second manual valve 13 at the same time, so as to facilitate the cleaning or replacement of the filter 11.

[0053] In some specific embodiments, a third manual valve 14 and a fourth manual valve 15 are respectively connected in series at both ends of the electric valve 7. Since the electric valve 7 is used to control the reflux flow of the heating medium, it may have valve core damage and needs to be repaired or replaced. Therefore, by closing the third manual valve 14 and the fourth manual valve 15, the heating medium at both ends of the electric valve can be sealed. At this time, the electric valve 7 can be repaired or directly replaced.

[0054] In some specific implementations, an emergency bypass 16 is further included. Two ends of the emergency bypass 16 are respectively connected to the outlet of the third manual valve 14 and the inlet of the fourth manual valve 15 . A fifth manual valve 17 is also connected in series to the emergency bypass 16 .

[0055] Since the heating medium needs to be continuously passed into the hot water coil 2 to maintain the temperature of the hot water coil 2, when inspecting and replacing the electric valve 7, in order to prevent the hot water coil 2 from being damaged by excessive pressure due to the continuous injection of hot water, the heating medium needs to be discharged. By setting the emergency bypass 16, the heating medium can be discharged by opening the fifth manual valve 17 and utilizing the emergency bypass 16, thereby realizing maintenance and replacement of the electric valve 7 without shutting down the system.

[0056] Working principle:

[0057] This application has two working states, which are described separately below:

[0058] The first type: when the temperature detected by the temperature sensor 3 is above the set temperature, at this time, the control circulation pump 9 is closed and the control valve 6 is opened. After entering the water inlet pipe 4, the hot water directly enters the hot water coil 2 through the control valve 6, and then enters the return pipe 5 from the hot water coil 2. Finally, it flows into the hot water return pipe through the electric valve 7. During the whole process, the temperature sensor 3 detects the temperature of the air outlet side of the hot water coil 2 in real time and feeds it back to the control circuit. When the detected temperature is relatively high, the control circuit reduces the opening of the control valve 6 and increases the opening of the electric valve 7, so that the flow rate of the heating medium entering the hot water coil 2 is reduced and the discharge flow rate is increased, thereby gradually reducing the outlet temperature of the air heated by the hot water coil 2; if the detected temperature is relatively low, the control circuit increases the opening of the control valve 6 and reduces the opening of the electric valve 7, so that the flow rate of the heating medium entering the hot water coil 2 is increased and the discharge flow rate is reduced, thereby gradually increasing the outlet temperature of the air heated by the hot water coil 2, so as to maintain the temperature of the air outlet side of the hot water coil 2 always maintained in the set temperature range.

[0059] The second type: when the temperature detected by the temperature sensor 3 is lower than the set temperature, at this time, the circulation pump 9 is controlled to be turned on, and then the control valve 6 is closed, and the opening of the electric valve 7 is reduced at the same time, so that the heating medium entering the water inlet pipe 4 all passes through the circulation pump 9 into the hot water coil 2 (that is, it no longer flows through the control valve 6, that is, the inflow of the heating medium is no longer controlled, but the discharge of the heating medium will be controlled). At the same time, part of the heating medium flowing through the hot water coil 2 passes through the check valve 10 again and is injected into the hot water coil 2 through the circulation pump 9. At this time, the hot water in the hot water coil 2 has a fast flow rate and a sufficient amount of hot water during circulation, which can ensure that the outlet air temperature meets the requirements as much as possible, or at least prevent the hot water coil 2 from being frozen and cracked.

[0060] The circulation pump 9 can realize a constant flow heat exchange cycle, that is, the circulation pump 9 performs water pumping operation at the maximum frequency, and the water pumping amount does not change during the whole process, that is, the purpose of constant flow is achieved; secondly, once the circulation pump 9 is turned on, part of the heating medium flowing through the hot water coil 2 will be combined with the new heating medium entering the water inlet pipe 4 and then enter the hot water coil 2 again. In this process, part of the heating medium is always reused, that is, the purpose of heat exchange cycle is achieved.

[0061] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A fresh air air conditioning box hot water coil antifreeze pipeline system, wherein a hot water coil (2) is arranged in the air duct of the fresh air air conditioning box (1) to adjust the air outlet temperature to a set temperature, characterized in that: The antifreeze pipeline system comprises a water inlet pipeline (4), a water return pipeline (5) and a temperature sensor (3); The water inlet pipeline (4) has an inlet and an outlet, the inlet of the water inlet pipeline (4) serves as an injection port for the heating medium, the outlet of the water inlet pipeline (4) is connected to the inlet of the hot water coil (2), and a control valve (6) is connected in series to the water inlet pipeline (4); The return water pipeline (5) has an inlet and an outlet, the inlet of the return water pipeline (5) is connected to the outlet of the hot water coil (2), the outlet of the return water pipeline (5) serves as a return port for the heating medium, and an electric valve (7) is connected in series to the return water pipeline (5); The temperature sensor (3) is arranged in the fresh air air conditioning box (1) and located on the air outlet side of the hot water coil (2), and is used to detect the temperature of the air after passing through the hot water coil (2); It also includes a circulation pipeline (8), the two ends of which are respectively connected to the water inlet side and the water outlet side of the control valve (6), and a circulation pump (9) is connected in series to the circulation pipeline (8); It also includes a check valve (10), the water inlet end of the check valve (10) is connected to the outlet of the hot water coil (2), and the water outlet end of the check valve (10) is connected to the water inlet side of the circulation pump (9); The antifreeze pipeline system further comprises a control circuit, which is electrically connected to the temperature sensor (3), the control valve (6), the electric valve (7) and the circulation pump (9).

2. The antifreeze piping system for hot water coils of fresh air air conditioner boxes according to claim 1 is characterized in that: A filter (11) is connected in series on the water inlet pipeline (4) at the water inlet side of the control valve (6).

3. The antifreeze piping system for hot water coils of fresh air air conditioner boxes according to claim 2 is characterized in that: A first manual valve (12) and a second manual valve (13) are respectively connected in series at both ends of the filter (11).

4. The antifreeze piping system for hot water coils of fresh air air conditioner boxes according to claim 1 is characterized in that: A third manual valve (14) and a fourth manual valve (15) are respectively connected in series at both ends of the electric valve (7).

5. The antifreeze piping system for hot water coils of fresh air air conditioner boxes according to claim 4 is characterized in that: It also includes an emergency bypass (16), the two ends of which are respectively connected to the outlet of the third manual valve (14) and the inlet of the fourth manual valve (15), and the emergency bypass (16) is also connected in series with a fifth manual valve (17).

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