Underground air duct wall temperature control system

Abstract

The present invention discloses a temperature control system for the wall surface of an underground air duct, which includes a static pressure box. The static pressure box is annularly arranged on the wall surface near the air duct opening. On the side of the static pressure box facing the air duct opening, there are two slit-type jet nozzles. A fan is arranged at the position below the static pressure box, and the fan is connected to a heat-insulating air duct. The fan can directly introduce external air into the static pressure box and form two air films from the two slit-type jet nozzles. The inner air film is arranged in contact with the wall surface, and the inner air film controls the temperature of the wall surface to make the wall surface temperature consistent with the external ambient air temperature. The outer air film is arranged at an interval from the inner air film and on the side far from the wall surface. The outer air film can block the heat transfer of the exhaust air in the air duct to the inner air film to ensure that the temperature of the air duct wall surface is not affected by the exhaust air temperature. The temperature control system for the wall surface of the underground air duct of the present invention effectively reduces the temperature difference between the wall surface temperature of the underground air duct opening and the outdoor environment, achieving the purpose of concealing the exhaust air of the underground air duct.

Description

Technical Field

[0001] The present invention relates to the field of exhaust air from underground air ducts, and particularly to a temperature control system for the wall surface of an underground air duct. Background Art

[0002] China has a vast territory, rich and complex geological types. Therefore, underground engineering occupies an important position in the field of engineering construction in China and is widely used in fields such as railways, water conservancy, mining, military, highways, subways, undersea tunnels, and residences. At present, underground engineering generally has a need for exhaust air and ventilation. However, due to seasonal differences or temperature differences between morning and evening, the temperature difference between the wall surface of the underground air duct opening and the external environment is relatively large, resulting in obvious infrared signs on the wall surface of the air duct opening, and the purpose of concealed emission cannot be achieved for special projects.

[0003] In summary, underground special projects require concealed exhaust air, and the temperature difference between the wall surface of the air duct opening and the environment needs to be controlled within a specified range. Summary of the Invention

[0004] The present invention provides a temperature control system for the wall surface of an underground air duct, which has the effect of reducing the temperature difference between the wall surface of the underground air duct opening and the outdoor environment and achieving concealed exhaust air from the underground air duct. The specific technical solutions are as follows:

[0005] A temperature control system for the wall surface of an underground air duct, which includes a static pressure box. The static pressure box is annularly arranged on the wall surface near the air duct opening. On the side of the static pressure box facing the air duct opening, there are two slit-type jet nozzles. A fan is arranged in the static pressure box. One end of the fan is connected to one end of a heat-insulating air duct, and the other end of the heat-insulating air duct is arranged outside the air duct. The fan can directly introduce external air into the static pressure box and form two air films from the two slit-type jet nozzles. The inner air film is arranged in contact with the wall surface, and the inner air film controls the temperature of the wall surface to make the wall surface temperature consistent with the external ambient air temperature. The outer air film is arranged at an interval from the inner air film and on the side far from the wall surface. The outer air film can block the heat transfer of the exhaust air in the air duct to the inner air film to ensure that the temperature of the air duct wall surface is not affected by the exhaust air temperature.

[0006] Further, the fan is arranged at the bottom of the static pressure box, and the heat-insulating air duct is buried in the middle position at the bottom of the air duct. The heat-insulating air duct is connected to the air inlet of the fan.

[0007] Further, there are two fans, which are respectively arranged on both sides of the heat-insulating air duct at the bottom of the static pressure box.

[0008] Further, there are multiple static pressure boxes, and the multiple static pressure boxes are connected end to end and arranged annularly in contact with the air duct wall surface.

[0009] Further, the cross-section of each static pressure box is a gradually decreasing tapered cross-section from bottom to top to ensure the static pressure balance in each static pressure box and similar jet velocities.

[0010] Furthermore, a wall temperature sensor is buried at a position close to the inner wall surface of the air duct to detect the temperature of the wall surface; an ambient temperature sensor is arranged outside the air duct opening to detect the ambient temperature; thereby, the temperature difference threshold between the wall surface and the external environment is calculated.

[0011] Furthermore, there are three wall temperature sensors, which are respectively arranged on the bottom of the air duct, on the side wall of the air duct, and on the top wall of the air duct to ensure the accuracy of the detected wall surface temperature.

[0012] Furthermore, the temperature difference threshold is that the temperature difference between the wall temperature of the air duct and the temperature of the external space does not exceed 4°C.

[0013] Furthermore, a control cabinet is arranged inside the air duct. The control cabinet is connected to the wall temperature sensor, the ambient temperature sensor, and the fan. The control cabinet can change the air volume of the fan according to the temperature difference threshold between the wall surface and the external environment, so as to ensure that the temperature difference threshold does not exceed 4°C.

[0014] Furthermore, the width of the air duct is L, and the distance from the side of the static pressure box provided with the slit-type jet nozzle to the air duct opening is also L.

[0015] The structural design of the underground air duct wall temperature control system of the present invention is ingenious. The external air is introduced into the annular static pressure box by the fan and forms two layers of air films from the two slit-type jet nozzles, so as to control the temperature of the wall surface of the mouth part air duct, reduce the temperature difference between the wall surface temperature of the underground air duct opening and the outdoor environment, and achieve the purpose of concealed exhaust of the underground air duct. In addition, the air volume of the fan is intelligently controlled by the PLC, which reduces the energy consumption of the fan while ensuring the temperature threshold, and effectively meets the requirements of concealment and energy conservation for special projects.

[0016] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the present invention more obvious and understandable, the following specifically illustrates the specific embodiments of the present invention. Brief Description of the Drawings

[0017] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0018] Figure 1 is the top view of the underground air duct wall temperature control system of the present invention;

[0019] Figure 2 is the transverse sectional view at the middle position of the underground air duct wall temperature control system of the present invention;

[0020] Figure 3 It is a longitudinal sectional view at the front position of the plenum chamber of the underground air duct wall temperature control system of the present invention;

[0021] Figure 4 It is a longitudinal sectional view at the front position of the wall temperature sensor of the underground air duct wall temperature control system of the present invention;

[0022] Figure 5 It is a transverse sectional view at the position where the plenum chamber of the underground air duct wall temperature control system of the present invention is close to the side wall surface. Detailed implementation manners

[0023] In order to better understand the purpose, function and specific design of the present invention, the underground air duct wall temperature control system of the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] As Figures 1-5 shown, the underground air duct wall temperature control system of the present invention includes a plenum chamber 3, the plenum chamber 3 is annularly arranged on the wall surface near the outlet of the air duct 1, two slit-type jet nozzles 4 are arranged on the side of the plenum chamber 3 facing the outlet of the air duct 1, a fan 2 is arranged in the plenum chamber 3, one end of the heat-insulating air duct 5 is connected to the fan 2, the other end of the heat-insulating air duct 5 is arranged outside the air duct 1, the fan 2 can directly introduce the external air into the plenum chamber 3 and form two air films from the two slit-type jet nozzles 4; the inner air film is arranged in contact with the wall surface, and the inner air film controls the temperature of the wall surface to make the wall surface temperature consistent with the external ambient temperature; the outer air film is arranged at an interval from the inner air film and on the side far from the wall surface, and the outer air film can block the heat transfer of the internal exhaust air of the air duct 1 to the inner air film to ensure that the wall surface temperature of the air duct 1 is not affected by the exhaust air temperature.

[0025] Specifically, as Figure 2 shown, the fan 2 is arranged at the bottom of the plenum chamber 3, the heat-insulating air duct 5 is buried in the middle position at the bottom of the air duct 1, and the heat-insulating air duct 5 is connected to the air inlet of the fan 2. It can be understood that one fan 2 can be buried together with the heat-insulating air duct 5 at the bottom of the air duct 1. Preferably, there are two fans 2 in this embodiment, which are respectively arranged on both sides of the heat-insulating air duct 5 at the bottom of the plenum chamber 3. Blowing air from the bottom on both sides of the plenum chamber 3 by using two fans 2 can ensure sufficient pressure in the plenum chamber 3 so as to ensure the jet pressure of the slit-type jet nozzles 4 and ensure the reliability of the inner air film and the outer air film during operation.

[0026] As shown in Figure 3, there are multiple static pressure chambers 3. The multiple static pressure chambers 3 are connected end to end and arranged annularly in close fit with the wall surface of the air duct 1. The segmented setting of the static pressure chamber 3 facilitates the installation of the static pressure chamber 3 inside the air duct 1 and improves the installation efficiency of the static pressure chamber 3. In addition, when a certain static pressure chamber 3 fails, it is also convenient to inspect and repair the static pressure chamber 3.

[0027] It should be noted that, as Figure 4 shown, the cross-section of each static pressure chamber 3 is a gradually decreasing tapered cross-section from bottom to top to ensure the static pressure balance inside each static pressure chamber 3 and similar jet velocities.

[0028] Specifically, the basic condition for achieving uniform air supply is: first, it is necessary to ensure that the static pressure at each position in the height direction of the static pressure chamber 3 remains equal or approximate. The wind speed is high at the position close to the fan 2, and as the distance increases, the wind speed blown by the fan 2 gradually decreases. Therefore, the cross-section of each static pressure chamber 3 is a gradually decreasing tapered cross-section from bottom to top, so that the volume below the static pressure chamber 3 is large and the volume above is small, thereby reducing the cross-section along the direction of air flow and converting the surplus static pressure into dynamic pressure to balance the pressure at different positions inside the static pressure chamber 3.

[0029] As Figure 5 shown, a wall temperature sensor 7 is buried at the position of the inner outlet wall surface of the air duct 1 close to it to detect the temperature of the wall surface; an ambient temperature sensor 8 is arranged outside the opening of the air duct 1 to detect the ambient temperature; thereby calculating the temperature difference threshold between the wall surface and the external environment.

[0030] There are three wall temperature sensors 7 in this embodiment. The three wall temperature sensors 7 are all 200 mm away from the air duct opening, and their heights are respectively set at the position 500 mm away from the bottom of the air duct 1, at the position of the side wall height H1 of the air duct 1 (the connection position of the vertical wall surface and the arc wall surface of the air duct), and at the middle position of the arc top wall of the air duct 1 to ensure the accuracy of the detected wall surface temperature.

[0031] It should be noted that the temperature difference threshold is that the temperature difference between the wall surface of the air duct 1 and the external space temperature does not exceed 4 °C to ensure the concealed exhaust of the underground air duct 1. Therefore, the fan 2 in this embodiment uses a DC variable speed EC fan 2. When the temperature difference threshold exceeds 4 °C, the DC variable speed EC fan 2 increases the air volume until the temperature difference between the wall surface and the environment meets the requirements. When the temperature difference threshold is less than 4 °C, the EC fan 2 operates at a low speed to achieve the best balance of maintaining the control of the wall temperature and energy-saving operation.

[0032] To achieve the above object, a control cabinet is provided inside the air duct 1 of this embodiment. The control cabinet 6 is electrically connected to the wall temperature sensor 7, the ambient temperature sensor, and the fan 2 through a data line 9. The control cabinet 6 can change the air volume of the fan 2 according to the temperature difference threshold between the wall and the external environment, so as to ensure that the temperature difference threshold does not exceed 4°C. The control cabinet 6 can be controlled by an existing PLC control cabinet.

[0033] In addition, through CFD simulation calculations and on-site test verifications of multiple projects, when the distance from the side of the static pressure box 3 with the slot-type jet nozzles 4 to the opening of the air duct 1 is also L when the width of the air duct 1 is L, the effect of wall temperature control can be well achieved.

[0034] The structural design of the wall temperature control system of the underground air duct of the present invention is ingenious. By introducing external air into the annular static pressure box through the fan and forming two layers of air films from the two slot-type jet nozzles, the wall temperature of the outlet part of the air duct is controlled, reducing the temperature difference between the wall of the outlet part of the underground air duct and the outdoor environment, achieving the purpose of concealed exhaust of the underground air duct. In addition, the air volume of the fan is controlled by PLC intelligence, reducing the energy consumption of the fan while ensuring the temperature threshold, effectively meeting the requirements of concealment and energy conservation for special projects.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An underground air duct wall temperature control system, characterized in that, it includes static pressure boxes. There are multiple static pressure boxes, and the multiple static pressure boxes are connected end to end. The static pressure boxes are annularly attached to the wall near the air duct outlet. On the side of the static pressure box facing the air duct outlet, there are two slit-type jet nozzles. The cross-section of each static pressure box is a gradually decreasing gradient cross-section from bottom to top to ensure the static pressure balance in each static pressure box and similar jet velocities; a fan is arranged at the position below the static pressure box. The fan is connected to one end of a heat-insulating air duct, and the other end of the heat-insulating air duct is arranged outside the air duct. The fan directly introduces external air into the static pressure box and forms two air films from the two slit-type jet nozzles; the inner air film is attached to the wall, and the inner air film controls the temperature of the wall. A wall temperature sensor is buried at the position near the wall of the inner outlet of the air duct to detect the temperature of the wall; an ambient temperature sensor is arranged outside the air duct outlet to detect the ambient temperature; thereby calculating the temperature difference threshold between the wall and the external environment; a control cabinet is arranged in the air duct, and the control cabinet is connected to the wall temperature sensor, the ambient temperature sensor, and the fan. The control cabinet changes the air volume of the fan according to the temperature difference threshold between the wall and the external environment to make the wall temperature consistent with the outside ambient temperature; the outer air film is arranged at an interval from the inner air film and on the side far from the wall. The outer air film blocks the heat transfer of the exhaust air in the air duct to the inner air film to ensure that the temperature of the air duct wall is not affected by the exhaust air temperature.

2. The underground air duct wall temperature control system according to claim 1, characterized in that, the fan is arranged at the bottom of the static pressure box, and the heat-insulating air duct is buried at the middle position of the bottom of the air duct. The heat-insulating air duct is connected to the air inlet of the fan.

3. The underground air duct wall temperature control system according to claim 2, characterized in that, there are two fans, which are respectively arranged on both sides of the heat-insulating air duct at the bottom of the static pressure box.

4. The underground air duct wall temperature control system according to claim 1, characterized in that, there are three wall temperature sensors, which are respectively arranged at the bottom of the air duct, on the side wall of the air duct, and on the top wall of the air duct to ensure the accuracy of the detected wall temperature.

5. The underground air duct wall temperature control system according to claim 1, characterized in that, the temperature difference threshold is that the temperature difference between the air duct wall temperature and the external space temperature does not exceed 4°C.

6. The underground air duct wall temperature control system according to claim 1, characterized in that, the width of the air duct is L, and the distance from the side of the static pressure box with the slit-type jet nozzle to the air duct opening is also L.

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