A variable air volume device with purging function

Abstract

This utility model discloses a variable air volume (VAV) device with a purging function, including a valve body, a measuring module, an air volume regulating component, and a gas storage tank. The air volume regulating component includes a valve stem positioned above the valve body and a damper blade mounted on the valve stem, adjusting the air volume by rotating the valve stem. The measuring module's detection tube is fixed inside the valve body and located in front of the air volume regulating component. The measuring module is used to collect the regional pressure difference in a local area and is connected to a differential pressure sensor through a sampling channel to achieve regional pressure difference measurement. The gas storage tank stores high-pressure gas and is connected to a purging channel for purging the inside of the valve body. A purging control valve is provided in the purging channel to release the high-pressure gas in the gas storage tank for purging the internal cavity of the detection tube or the rectifier component. This design incorporates a related air pump for high-pressure gas generation, achieving an integrated design of purging gas generation and VAV regulation, thus improving the applicability of the VAV device.

Description

Technical Field

[0001] This utility model relates to industrial and civil air conditioning and ventilation duct systems, specifically to a variable air volume device with a purging function. Background Technology

[0002] Variable air volume (VAV) devices are widely used in industrial and civil air conditioning and ventilation duct systems for measuring and regulating airflow. VAV devices include VAV valves, VAV devices with heating and cooling coils, and more.

[0003] Variable air volume (VAV) devices typically use an average differential pressure measurement component to measure airflow. The differential pressure sensor transmits the differential pressure signal to the control device, which then performs calculations and adjusts the airflow of the corresponding airflow regulating component via a control valve actuator.

[0004] In air with high dust concentration, this type of variable air volume device may be affected by blockages in the detection tube and rectifier. Under many working conditions, there is no compressed air source or sufficient external compressed air flow rate to purge the internal parts of the variable air volume device. Summary of the Invention

[0005] This invention designs a purging function for variable air volume devices, further improving the applicability of these devices. Specifically, a gas storage tank is installed to store high-pressure gas and connected to a purging channel for internal purging of the valve body. A purging control valve is installed in the purging channel to release the high-pressure gas from the storage tank for internal purging.

[0006] The purging channel is connected to at least part of the detection tube in the measurement module for purging the internal cavity of the detection tube; one end of the purging channel may be located near the rectifier for purging the rectifier.

[0007] During the release process, the relative pressure value of the gas storage tank in the released termination state is less than half of the relative pressure value of the high-pressure gas.

[0008] The gas storage tank is connected to an external high-pressure gas pipeline to obtain the high-pressure gas.

[0009] The variable air volume device includes an air pump used to fill the gas storage tank to obtain the high-pressure gas. The air pump can be a diaphragm pump or a piston pump; a filter can be installed at the air inlet of the air pump. Attached Figure Description

[0010] Figure 1 Example diagram of a variable air volume device valve body with purging function.

[0011] Figure 2 Example diagram of a controllable measurement module with a purge channel in a manifold.

[0012] Figure 3 This is a purging principle diagram. Detailed Implementation

[0013] The example of this utility model is based on the variable air volume device with multiple measurement modules involved in application number PCT / CN2023 / 074862 and invention application number 2023100762358. The air volume measurement principle, control principle, and names and definitions of various components are the same as those in the published documents.

[0014] Figure 1 This is a cross-sectional view of an example valve body for a variable air volume (VAV) device with a purging function. The valve body 521 is made of galvanized steel sheet, but it can also be made of thin sheet of other materials and thicknesses. It uses a combination of a measuring valve body and an air valve body, with the two parts fixed together by bolts, or other fastening methods such as clamps. The example uses two measuring modules, each with 12 total pressure measuring holes. Each measuring module has its own corresponding airflow regulating component 9 and air valve actuator 8 for its corresponding measuring sub-area. An air tank 113 and a miniature air pump 114 are fixedly mounted on the valve body. The air inlet 11401 is connected to the air inlet 11301 of the air tank 113 via an air storage pipe 11502. The connection between the air tank and the measuring modules is shown in [details omitted]. Figure 3 .

[0015] A flow rectifier can be installed at the front of the measurement module to reduce the turbulence of the measurement cross section. The flow rectifier includes multiple straight channels through which airflow passes to reduce the turbulence of the measurement cross section. The straight channel through which airflow passes is straight from the inside to the outlet. The hydraulic diameter of the straight channel is less than 0.2 times the hydraulic diameter of the measurement channel, and the length of the straight channel is greater than 0.2 times the hydraulic diameter of the straight channel.

[0016] A channel partition plate 2 is welded inside the measurement channel. A solenoid valve 10800 is installed on the sampling tube of the first high-pressure main pipe 107ha, and a solenoid valve 10800 is installed on the sampling tube of the second high-pressure main pipe 108ha. These two sampling tubes are connected to the second high-pressure concentrator pipe 10903. A solenoid valve 10800 is installed on the sampling tube of the first low-pressure main pipe 107la, and a solenoid valve 10800 is installed on the sampling tube of the second low-pressure main pipe 107la. These two sampling tubes are connected to the second low-pressure concentrator pipe 10904. The high-pressure concentrator pipe and the low-pressure concentrator pipe are connected to the differential pressure sensor transmitter 4. The four solenoid valves are sampling switching components, which can be controlled by the controller to cyclically sample the differential pressure of the measurement sub-regions. The controller 7 calculates the average differential pressure of the two measurement sub-regions (i.e., the regional differential pressure) and drives the airflow adjustment unit to adjust the airflow. For example, the controller can close one airflow adjustment component to shut down the corresponding measurement sub-region, thereby increasing the measurement flow rate. In practical engineering, the same airflow regulating component and damper actuator can be used for both measurement sub-areas. When the damper actuator is activated, both measurement sub-areas are adjusted simultaneously, thereby reducing manufacturing costs. The channel partition 2 can be omitted as it is not a necessary component. The aforementioned sampling switching component can be a manual valve for manual purging and measurement switching.

[0017] Each airflow regulating component 9 includes multiple air valve blades and air valve partition plates mounted on the valve stem. The air valve blades are located inside the valve body and the airflow is adjusted by rotating the valve stem. It also includes a transmission component.

[0018] The example includes a valve body, multiple measurement modules, and an airflow regulating component. The airflow regulating component includes a damper blade mounted on a valve stem, located inside the valve body, which regulates airflow by rotating the valve stem. The detection tube of the measurement module is fixedly connected to the valve body and located in front of the airflow regulating component. The measurement module collects the regional pressure difference in a local area and connects to a differential pressure sensor via a sampling channel to achieve regional pressure difference measurement. The differential pressure sensor transmits the differential pressure signal to a control device, which performs calculations and regulates the airflow of the corresponding airflow regulating component by controlling the damper actuator.

[0019] The improvement of this utility model is that a first purge tube 11101 is connected to the first high-pressure main pipe 107ha, a second purge tube 11102 is connected to the second high-pressure main pipe 108ha, a third purge tube 11103 is connected to the sampling tube corresponding to the first low-pressure main pipe 107la, and a fourth purge tube 11104 is connected to the sampling tube corresponding to the second low-pressure main pipe 108la.

[0020] The connection positions of each of the above-mentioned purge tubes can be adjusted, and they can be connected to the main pipe or sampling tube for convenience. The purge tubes can be made of various flexible materials such as PVC and polyurethane, or even metal. The above-mentioned purge tubes can be designed in various shapes and can be collectively referred to as purge channels.

[0021] As shown in the purging principle diagram Figure 3 As shown, a miniature air pump 114 is used. It can be a diaphragm pump, piston pump, or rotary vane pump, all driven by a miniature low-pressure motor. The no-load flow rate can be below 30 L / MIN, generating high-pressure gas below 10 bar. The storage tank can be designed with a storage pressure below 10 kg; the 10 bar is a relative pressure value, i.e., the pressure relative to the surrounding atmosphere. During the purging and release process, the relative pressure value of the storage tank at the end of the release can be less than half of the relative pressure value of the high-pressure gas, and under normal circumstances, it can be released to 0. Due to the small size of the compressed air generation device, it can be customized for a single variable air volume (VAV) device; VAV devices can be configured with a compressed air generation device independently, or several VAV devices can be combined to form a single compressed air generation device; the compressed air generation device can be fixed to the valve body, air duct, or ceiling.

[0022] Diaphragm pumps typically use a low-pressure motor to drive a diaphragm outwards from the pump chamber, increasing the chamber volume and creating negative pressure to draw in air. During the discharge phase, the diaphragm is driven to move in the opposite direction, reducing the pump chamber volume and generating high-pressure gas for output. This continuous reciprocating motion of the diaphragm ensures continuous delivery of high-pressure gas. Miniature diaphragm pumps generally have multiple diaphragms and can generate 9 bar of high-pressure air even at low flow rates. Miniature piston pumps, on the other hand, typically use a low-pressure motor to drive a piston within a cylinder via a crankshaft or eccentric wheel, creating volume changes to draw in and produce high-pressure gas. The pressure can be significantly higher than that of a diaphragm pump.

[0023] The air inlet 11401 of the miniature air pump is connected to the air inlet 11301 of the air storage tank 113 via the air storage pipe 11502, allowing the air tank to be filled with air during the idle time of purging. A one-way valve can be installed at the outlet of the air storage pipe or the air storage tank. If the miniature air pump has a built-in one-way valve, a separate one-way valve is not required on the air storage pipe. The air inlet 11402 of the miniature air pump can be used for free air intake or can be equipped with an air filter for air intake.

[0024] The gas storage tank can also be designed with a pressure transmitter, allowing the control device to automatically start and stop the miniature air pump. The volume of the gas storage tank can be designed to be below 300ML, and it can be made of various metal materials. A safety valve can be installed on the gas storage tank.

[0025] The gas storage outlet 11302 of the gas storage tank is connected to the first purge pipe 11101, the second purge pipe 11102, the third purge pipe 11103, and the fourth purge pipe 11104 via a purge main pipe 11501 and corresponding tee fittings, elbow fittings, etc. A first purge control valve 11201, a second purge control valve 11202, a third purge control valve 11203, and a fourth purge control valve 11204 are respectively installed in the middle of the first purge pipe 11101, the second purge control valve 11202, the third purge control valve 11203, and the fourth purge control valve 11204. Each purge control valve is electrically connected to and controlled by a control device; alternatively, it can be connected to the control device via wired or wireless communication.

[0026] The purging system operates as follows: when the measuring module is idle, the control device activates the corresponding purging control valve to purge the high-pressure main pipe, the internal cavity of the high-pressure section's detection tube, the low-pressure main pipe, and the internal cavity of the low-pressure section's detection tube. Once the measuring module has finished purging, the corresponding purging control valve closes, and the gas storage tank is refilled with high-pressure gas by the air pump.

[0027] This device boasts low cost and reliable structure. As part of a variable air volume (VAV) system, it significantly improves applicability in industrial and civil applications where there is no compressed air source or insufficient external compressed air velocity. In some cases, the total flow rate of the compressed air system is low or the pipeline design velocity is insufficient; by utilizing the air tank design, a narrower inlet pipe can be designed, reducing project costs and improving system stability. In such situations, effective purging can be achieved using the factory's compressed air system without the need for a dedicated purging pump.

[0028] Due to the characteristics of variable air volume devices with multiple measurement modules, when they use differential pressure cyclic measurement, at least some measurement modules are in an idle state. At this time, they can be purged by a compressed air generator without affecting the measurement.

[0029] Figure 2 This diagram illustrates an example of a purge channel configuration for multiple measurement modules using a manifold-controlled measurement module setup. The example shown can accommodate up to nine measurement modules during measurement. Each measurement module is a first detection tube 1rl; 1rl employs a diamond-shaped averaging pitot tube design, featuring four full-pressure measurement ports and four low-pressure measurement ports. It connects to a high-pressure manifold 11, a low-pressure manifold 12, and two solenoid valves 10800, constituting one measurement module. The number of measurement modules in this differential pressure measuring device can be flexibly varied depending on the conduction combinations of the solenoid valves 10800, forming different combinations of measurement sub-regions.

[0030] In the example, a first high-pressure manifold 10901 and a fifth purge pipe 11005 are connected to the lower part of the third high-pressure manifold 100h, and a first low-pressure manifold 10902 and a sixth purge pipe 11006 are connected to the lower part of the third low-pressure manifold 100l. When using... Figure 3 With the same compressed air generation device design, the measurement module can also be cyclically purged.

[0031] Variable air volume (VAV) devices with multiple measurement modules can be purged using commonly used compressed air pipe connections, or various gases such as nitrogen. The purging gases mentioned above are collectively referred to as purging gases; they possess a certain pressure and can achieve purging from the inside of the detection chamber to the measurement port. VAV devices include VAV valves, VAV devices with heating and cooling coils, etc.

[0032] For variable air volume (VAV) devices employing a single average differential pressure measuring component (i.e., a single measuring module), in most cases, due to the low control speed requirements, the measuring module can pause measurement, allowing the compressed air generator to purge the system before resuming measurement. In terms of system design, only a sampling switching component needs to be added to the sampling pipe. During purging, the pressure sampling pipeline is shut off to prevent sensor damage. Therefore, this compressed air generator and purging design is also applicable to all VAV devices with an average differential pressure measuring component.

[0033] This purging design can be combined with existing technology to purge the detection tube at regular intervals; or it can be used to monitor the monitoring port with a camera for timely purging.

[0034] When the variable air volume (VAV) device is equipped with a rectifier, this purging design can incorporate a purging pipe and control logic to achieve purging of the rectifier. One end of the purging pipe can be positioned near the rectifier, and the pipe opening can be designed in various shapes to facilitate cleaning. Furthermore, an automatically controlled robotic arm can be designed inside the valve body, with a camera monitoring the surface cleanliness of the rectifier, and remotely operated to move and purge or perform vacuum suction.

[0035] The structure of the aforementioned variable air volume (VAV) device can be summarized as follows: it includes a valve body, a measurement module, an air volume regulating component, and an air tank. The air volume regulating component includes a valve stem positioned above the valve body and a damper blade mounted on the valve stem, adjusting the air volume by rotating the valve stem. The detection tube of the measurement module is fixed inside the valve body and located in front of the air volume regulating component. The measurement module is used to collect the regional pressure difference in a local area and is connected to a differential pressure sensor through a sampling channel to achieve regional pressure difference measurement. The air tank stores high-pressure gas and is connected to a purging channel for purging the inside of the valve body. A purging control valve is provided in the purging channel to release the high-pressure gas in the air tank for internal purging.

[0036] The terms “first,” “second,” and “third” used in this article are for descriptive purposes only and should not be interpreted as indicating or implying relative importance.

[0037] Finally, it should be noted that the embodiments described in this article have been described in detail. For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A variable air volume device having a purge function, characterized by, The system includes a valve body, a measurement module, an airflow regulating component, and an air tank. The airflow regulating component includes a valve stem positioned above the valve body and a damper blade mounted on the valve stem, allowing airflow to be adjusted by rotating the valve stem. The measurement module's detection tube is fixed inside the valve body and located in front of the airflow regulating component. The measurement module is used to collect regional pressure differences in a local area and is connected to a differential pressure sensor via a sampling channel to achieve regional pressure difference measurement. The air tank stores high-pressure gas and is connected to a purge channel for purging the inside of the valve body. A purge control valve is installed in the purge channel to release the high-pressure gas in the air tank for internal purging.

2. The variable air volume device of claim 1, wherein, The differential pressure sensor transmits a differential pressure signal to the control device, which performs calculations and adjusts the airflow of the corresponding airflow regulating component by controlling the air valve actuator.

3. The variable air volume device of claim 1, wherein, The purging channel is connected to at least a portion of the detection tube in the measurement module for purging the internal cavity of the detection tube.

4. The variable air volume device of claim 1, wherein, The variable air volume device includes a rectifier for reducing the turbulence of the measurement cross section, and one end of the purging channel is located near the rectifier for purging the rectifier.

5. The variable air volume device of claim 1, wherein, During the release process, the relative pressure value of the gas storage tank at the end of the release state is less than half of the relative pressure value of the high-pressure gas.

6. The variable air volume device of claim 1, wherein, The gas storage tank is connected to an external high-pressure gas pipeline to obtain the high-pressure gas.

7. The variable air volume device of claim 1, wherein, The variable air volume device includes an air pump, which is used to fill the air tank to obtain the high-pressure gas.

8. The variable air volume device of claim 7, wherein, The air pump is a diaphragm pump.

9. The variable air volume device of claim 7, wherein, The air pump is a piston pump.

10. The variable air volume device of claim 7, wherein, The air pump is equipped with a filter at its air inlet.

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