A laboratory ventilation system employing a locally controlled variable air volume valve

Abstract

This utility model relates to the field of ventilation and air conditioning, disclosing a laboratory ventilation system employing a locally controlled variable air volume (VAV) valve. The system includes components such as a supply fan, a supply VAV valve, an exhaust VAV valve, a room differential pressure sensor, a door magnetic sensor, a gateway, and a PLC. The locally controlled VAV valve adjusts the supply and exhaust air volumes, achieving precise control of room differential pressure and airflow. An airflow calculation module and an automatic adjustment module monitor the airflow in real time and adjust the valve opening. Based on feedback data, the system adjusts the frequency of the supply and exhaust fans, optimizing energy efficiency and reducing energy consumption. The system can select either local airflow control or local differential pressure control mode to ensure a safe and stable laboratory environment. A door magnetic signal allows the system to pause differential pressure adjustment when the door is opened, ensuring stable operation. This utility model effectively solves the problems of slow airflow adjustment, low control accuracy, and high energy consumption in existing technologies, achieving the technical effects of precise control of laboratory airflow and differential pressure, improved system energy efficiency, and reduced operating costs.

Description

Technical Field

[0001] This utility model relates to the field of ventilation and air conditioning, specifically to a laboratory ventilation system using a locally controlled variable air volume valve. Background Technology

[0002] In pharmaceutical laboratories, ventilation systems play a crucial role, primarily functioning to rapidly remove toxic and harmful pollutants generated during experiments and to replenish the laboratory with sufficient fresh air. To ensure laboratory safety, it is essential to maintain a stable pressure differential within the laboratory room to prevent outside air infiltration from affecting experiments. However, some existing laboratory ventilation systems cannot precisely control the room's pressure differential, especially in laboratories using natural air supply. These systems rely on the pressure difference created by the room's exhaust air, making it difficult to effectively control the pressure difference and ensure a stable indoor environment. Furthermore, traditional electric regulating valves cannot automatically, quickly, and accurately adjust the exhaust volume, impacting the stability and safety of the laboratory environment.

[0003] While some existing solutions utilize advanced ventilator valves to regulate exhaust volume, this technology is costly and its effectiveness is relatively limited. Therefore, there is an urgent need for a ventilation system that can automatically, quickly, and accurately regulate laboratory pressure differential and airflow at a lower cost. Utility Model Content

[0004] This invention provides a laboratory ventilation system employing a locally controlled variable air volume valve. By effectively controlling the laboratory's supply air and fume hood exhaust, it achieves precise control of the laboratory room pressure difference and automatic, rapid, and accurate adjustment of the exhaust volume, ensuring a safe and stable experimental environment while reducing the cost and energy consumption of the laboratory ventilation system. The specific technical solution is as follows: A laboratory ventilation system employing locally controlled variable air volume (VAV) valves includes: a supply fan, supply air duct, supply VAV valve, gateway, PLC, exhaust VAV valve, room differential pressure sensor, door magnetic sensor, exhaust fan, and exhaust duct. Both the supply and exhaust VAV valves are locally controlled VAV valves. The ventilation system primarily controls the room's differential pressure and the exhaust volume of the fume hoods. The temperature and humidity within the laboratory are controlled by the room's air conditioner.

[0005] Furthermore, the supply fan, exhaust fan, and locally controlled variable air volume (VAV) valve communicate with the PLC via a gateway. The PLC monitors the operating parameters and status of the ventilation system in real time: controls the start / stop and operating frequency adjustment of the supply and exhaust fans; sets the operating mode of the VAV valve (local air volume control or local differential pressure control); sets or modifies the target value of the room differential pressure; and sets or modifies the target value of the air volume, which can be set to two levels, such as working mode and duty mode, and can be switched with one click on the PLC control interface.

[0006] Furthermore, the locally controlled variable air volume valve includes a communication module, an air volume calculation module, and an automatic air volume / differential pressure adjustment module, and can be set to operate in either local air volume control or local differential pressure control mode. The air volume calculation module can calculate the passing air volume in real time. The communication module can transmit data such as real-time air volume, valve opening degree, and room differential pressure (in local differential pressure control mode) to the PLC.

[0007] Furthermore, when the damper operates in local airflow control mode, the automatic adjustment module adjusts the damper opening based on the deviation between the real-time airflow and the target airflow value, using a built-in PID algorithm and control program to stabilize the airflow near the target value.

[0008] Furthermore, when the damper operates in local differential pressure control mode, it receives data from the room differential pressure sensor in real time. Based on the deviation between the real-time differential pressure and the target value of the room differential pressure, it adjusts the opening of the damper through a built-in PID algorithm and control program to stabilize the room differential pressure near the target value. At the same time, in local differential pressure control mode, the damper can also be connected to a door magnetic signal. When the door is open, the automatic differential pressure adjustment program is paused and the valve opening remains unchanged; when the door is closed, the automatic differential pressure adjustment program is activated.

[0009] Furthermore, based on the feedback air volume (supply fan) or set air volume (exhaust fan) and feedback opening of the locally controlled variable air volume valve, the PLC adjusts the set frequency of the supply fan or exhaust fan to make at least one air valve close to the fully open state, thereby reducing the operating energy consumption of the fan. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the laboratory ventilation system of this utility model. Detailed Implementation

[0011] A laboratory ventilation system employing locally controlled variable air volume (VAV) valves includes a supply fan (1) and supply ductwork, a supply VAV valve (2), a gateway (3), a PLC (4), exhaust VAV valves (5), (6), (7), and (8), a room differential pressure sensor (9), a door magnetic sensor (10), an exhaust fan (11), and exhaust ductwork. Both the supply and exhaust VAV valves are locally controlled VAV valves. The ventilation system primarily controls the room differential pressure and the exhaust volume of the fume hoods; the temperature and humidity in the laboratory are controlled by the room's air conditioner.

[0012] The supply fan (1), exhaust fan (11), supply air variable air volume valve (2), and exhaust air variable air volume valves (5), (6), (7), and (8) communicate with the PLC (4) through the gateway (3). The PLC (4) monitors the operating parameters and status of the ventilation system in real time: controls the start / stop and operation frequency adjustment of the supply fan (1) and exhaust fan (11); sets the room pressure difference target value of the supply air variable air volume valve (2); sets the air volume target value of the exhaust air variable air volume valves (5), (6), (7), and (8). The air volume target value is set to two levels, which are divided into working mode and duty mode. The working mode is run during the daytime working hours, and the duty mode is run at other times. The switching is done through the PLC control interface.

[0013] The variable air volume valve (2) has an air volume calculation module, a communication module, an automatic adjustment module, etc., and is set to local differential pressure control as its working mode. The air volume calculation module can calculate the air volume passing through in real time. The automatic adjustment module receives data from the room differential pressure sensor (9) in real time, and adjusts the valve opening according to the deviation between the target room differential pressure value and the real-time differential pressure, so that the room differential pressure is stabilized near the target value through the built-in PID algorithm and control program. At the same time, the variable air volume valve (2) can receive the signal from the door magnet (10). When the door is open, the automatic differential pressure adjustment program can be paused and the valve opening remains unchanged; when the door is closed, the automatic differential pressure adjustment program is activated. The communication module transmits data such as real-time air volume, valve opening, and room differential pressure to the PLC (4).

[0014] The exhaust variable air volume valves (5), (6), (7), and (8) have an air volume calculation module, a communication module, and an automatic adjustment module, and are set to local air volume control as their working mode. The air volume calculation module can calculate the air volume passing through in real time. The communication module transmits the real-time air volume and valve opening data to the PLC (4). The automatic adjustment module communicates with the air volume calculation module and receives the real-time air volume value. Based on the deviation between the real-time air volume value and the target air volume value, it adjusts the valve opening through the built-in PID algorithm and control program to stabilize the air volume value near the target value.

[0015] Based on the air volume and opening degree fed back by the air supply variable air volume valve (2), the PLC (4) adjusts the set frequency of the air supply fan (1) so that the air supply variable air volume valve (2) is close to the fully open state, thereby reducing the operating energy consumption of the air supply fan (1). Based on the sum of the set air volumes of the exhaust variable air volume valves (5), (6), (7), and (8) and the opening degree of each valve, the PLC (4) adjusts the set frequency of the exhaust fan (11) so that at least one exhaust variable air volume valve is close to the fully open state, thereby reducing the operating energy consumption of the exhaust fan (11).

[0016] The beneficial effects of this utility model are as follows: 1. By employing a locally controlled variable air volume (VAV) valve to control the supply / makeup air volume and exhaust air volume, automatic, rapid, and accurate control of room pressure differential and exhaust air volume is achieved, ensuring the safety and stability of the experimental environment. Simultaneously, measuring room pressure differential and air volume does not require increasing the number of PLC I / O channels, and controlling room pressure differential and exhaust air volume does not consume PLC computing resources, thus reducing the cost of the control system.

[0017] 2. The exhaust volume of the fume hood is controlled by a local control type variable air volume valve, which avoids the risk of not being able to adjust automatically and quickly compared with ordinary electric valves, and reduces the cost of use compared with Venturi valves while achieving the same effect.

[0018] 3. The local control type variable air volume valve used in this utility model can provide feedback on air volume and opening degree. The supply fan / exhaust fan can be frequency-adjusted according to the air volume and valve opening degree, thereby reducing the operating energy consumption of the fan.

Claims

1. A laboratory ventilation system employing a locally controlled variable air volume valve, characterized in that: Includes a blower (1) and a blower duct, a blower variable air volume valve (2), a gateway (3), a PLC (4), an exhaust variable air volume valve (5), (6), (7), (8), a room differential pressure sensor (9), a door magnet (10), an exhaust fan (11) and an exhaust duct. The blower variable air volume valve (2) and the exhaust variable air volume valve (5), (6), (7), (8) are all locally controlled variable air volume valves. The blower (1), exhaust fan (11), and local control variable air volume valve communicate with the PLC (4) through the gateway (3); The PLC (4) monitors the operating parameters and status of the ventilation system in real time, controls the start / stop and operation frequency adjustment of the supply fan (1) and exhaust fan (11), sets the room pressure difference target value of the supply air volume valve (2), and sets the air volume target value of the exhaust air volume valves (5), (6), (7), and (8). The local control type variable air volume valve has a communication module, an air volume calculation module and an automatic adjustment module, and can be set to work mode as local air volume control or local differential pressure control. The local air volume control or local differential pressure control adjusts the opening of the air valve through a built-in PID algorithm and control program.

2. A laboratory ventilation system employing a locally controlled variable air volume valve according to claim 1, characterized in that: The variable air volume valve (2) is set to local differential pressure control. The automatic adjustment module of the variable air volume valve (2) receives data from the room differential pressure sensor (9) in real time. Based on the deviation between the target value of the room differential pressure and the real-time differential pressure, the valve opening is adjusted by the built-in PID algorithm and control program to stabilize the room differential pressure near the target value.

3. A laboratory ventilation system employing a locally controlled variable air volume valve according to claim 1, characterized in that: The exhaust variable air volume valves (5), (6), (7), and (8) are set to local air volume control. The air volume calculation module of the exhaust variable air volume valves (5), (6), (7), and (8) calculates the air volume passing through in real time. The automatic adjustment module of the exhaust variable air volume valves (5), (6), (7), and (8) communicates with the air volume calculation module and receives the real-time air volume value. Based on the deviation between the real-time air volume value and the target air volume value, the valve opening is adjusted through the built-in PID algorithm and control program to stabilize the air volume value near the target value.

4. A laboratory ventilation system employing a locally controlled variable air volume valve according to claim 1, characterized in that: The target air volume values ​​of the exhaust variable air volume valves (5), (6), (7), and (8) are set to two levels, namely working mode and duty mode.

5. A laboratory ventilation system employing a locally controlled variable air volume valve according to claim 2, characterized in that: The variable air volume valve (2) can receive the signal from the door magnet (10). When the door is open, the automatic differential pressure adjustment program is paused and the valve opening remains unchanged; when the door is closed, the automatic differential pressure adjustment program is activated.

6. A laboratory ventilation system employing a locally controlled variable air volume valve according to claim 1, characterized in that: Based on the air volume and opening degree fed back by the variable air volume valve (2), the PLC (4) adjusts the set frequency of the blower (1) so that the variable air volume valve (2) is close to the fully open state.

7. A laboratory ventilation system employing a locally controlled variable air volume valve according to claim 1, characterized in that: Based on the sum of the set air volumes of the exhaust variable air volume valves (5), (6), (7), and (8) and the opening status of each valve, the PLC (4) adjusts the set frequency of the exhaust fan (11) so that at least one exhaust variable air volume valve is close to fully open.

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