Self-sustaining device for high-level biosafety laboratories

Abstract

Self-keeping device for high-level biosafety laboratory belongs to the field of automatic control technology of biosafety laboratory. In order to solve the problem that the existing automatic control system cannot continue to send and exhaust air in the laboratory when the controller is short-circuited and other emergency situations occur, all signals are interrupted, and the fan stops running, resulting in loss of pressure in the laboratory. After the main self-keeping frequency converter receives the frequency control signal sent by the main controller, the speed of the corresponding main fan is controlled. When the main controller interrupts the output frequency control signal, the self-keeping signal is sent to the corresponding main fan to maintain the current speed of the corresponding main fan. When the electric valve is in the open state and the received on-off control signal is lost, the self-keeping circuit of the No. 1 electric actuator controls the electric valve to remain in the open state. When the current signal received by the analog electric actuator is lost, the corresponding electric valve is controlled to maintain the current opening degree. It is used for keeping the laboratory in a negative pressure environment.

Description

Technical Field

[0001] This invention relates to a self-holding device and belongs to the field of automatic control technology for biosafety laboratories. Background Technology

[0002] Pathogens handled in high-level biosafety laboratories are highly infectious and pathogenic, spreading via aerosols or with unknown transmission routes, and for which there are currently no effective vaccines or treatments. Therefore, maintaining a negative pressure environment and negative pressure gradient within the laboratory is the most important measure to prevent the spread of pathogenic microorganisms and is a key factor in ensuring the safe operation of the laboratory. Currently, the negative pressure environment in high-level biosafety laboratories is achieved through the laboratory's automatic control system (hereinafter referred to as the "automatic control system"). However, in emergency situations such as short circuits in the controller, all signals are interrupted, the fans stop operating, and the laboratory can no longer receive ventilation, leading to serious consequences such as depressurization.

[0003] Furthermore, GB50346-2011, the "Technical Specification for Biosafety Laboratory Buildings," requires high-level biosafety laboratories to be equipped with backup supply and exhaust fans. It also mandates the installation of UPS power supplies to ensure continuous power supply. However, redundancy measures for the automatic control system, such as controller redundancy, sensor redundancy, internal short circuits in control circuits, and on-site control methods to handle emergencies, are not considered. In actual operation, a failure in any link could lead to a serious biosafety accident. Currently, biosafety laboratories have many redundant control strategies for fan failures, such as setting up backup fans to immediately activate them after the main fan fails. However, laboratories may encounter multiple complex situations during operation, and current automatic control systems used in high-level biosafety laboratories cannot cope with emergencies such as controller failures, critical sensor failures, and power outages of controllers and modules due to internal short circuits in control loops.

[0004] Therefore, existing automatic control systems used in high-level biosafety laboratories have a number of problems. However, the main problem to be solved in this application is how to ensure that the fan continues to operate and continue to supply and exhaust air to the laboratory in case of emergency such as short circuit of the controller, so as to maintain the negative pressure of the laboratory. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that in existing automatic control systems, all signals are interrupted and the fan stops operating in emergency situations such as short circuits in the controller, thus preventing the continued supply and exhaust of air to the laboratory and causing depressurization. The invention proposes a self-maintaining device for high-level biosafety laboratories.

[0006] A self-holding device for high-level biosafety laboratories, the device comprising a main controller, an analog electric actuator, a main pressure sensor, a main air supply actuator, and a main exhaust actuator;

[0007] Both the main air supply actuator and the main exhaust actuator include a self-holding circuit for the No. 1 electric actuator, a main switching electric actuator, a main self-holding frequency converter, and a main fan;

[0008] The main pressure sensors installed on the air supply duct and the air exhaust duct are used to collect pressure data of the air supply duct and the air exhaust duct respectively, and send them to the main controller.

[0009] The main controller is used to receive pressure data from the air supply duct and simultaneously send control signals to the main air supply actuator installed in the air supply duct and send current signals to the analog electric actuator installed in the air supply duct; it is also used to receive pressure data from the exhaust duct and simultaneously send control signals to the main exhaust actuator installed in the exhaust duct and send current signals to the analog electric actuator installed in the exhaust duct. The control signals include simultaneously sending a frequency control signal to the main self-holding frequency converter and a switching control signal to the self-holding circuit of the first electric actuator.

[0010] Each main self-holding frequency converter is used to control the speed of the corresponding main fan after receiving the frequency control signal. When the main controller interrupts the output of the frequency control signal, it sends a self-holding signal to the corresponding main fan to maintain the current speed of the corresponding main fan.

[0011] Each No. 1 electric actuator self-holding circuit is used to control the electric valve on the corresponding main switch electric actuator to be open or closed after receiving the switch control signal. When the electric valve is in the open state and the main controller stops outputting the switch control signal, the electric valve is kept in the open state.

[0012] Each analog electric actuator is used to control the opening degree of the electric valve on the analog electric actuator after receiving a current signal. When the current signal is lost, it controls the corresponding electric valve to maintain the current opening degree.

[0013] Preferably, the device further includes a backup air supply actuator and a backup air exhaust actuator;

[0014] Both the standby air supply actuator and the standby air exhaust actuator include a self-holding circuit for the No. 2 electric actuator, a standby switch quantity electric actuator, a standby self-holding frequency converter, and a standby fan;

[0015] The main fan and standby fan in the air supply duct and exhaust duct are installed in parallel.

[0016] The main switch electric actuator is installed on the main fan side, and the standby switch electric actuator is installed on the standby fan side;

[0017] The main controller is also used to switch the control of the main self-holding frequency converter to the control of the standby self-holding frequency converter when the main self-holding frequency converter detects a fault in the corresponding main fan. The standby self-holding frequency converter controls the speed of the corresponding standby fan, and the standby switch quantity electric actuator is controlled to open or close through the self-holding circuit of the second electric actuator.

[0018] Preferably, the device further includes a backup pressure sensor;

[0019] The main controller is also used to take the average pressure of the main pressure sensor and the backup pressure sensor on the air supply duct as the pressure data of the air supply duct; and to take the average pressure of the main pressure sensor and the backup pressure sensor on the exhaust duct as the pressure data of the exhaust duct.

[0020] It is also used to determine that the main pressure sensor or the backup pressure sensor has malfunctioned when the difference between the pressure data of the main pressure sensor or the backup pressure sensor and the set value is greater than the preset difference. In this case, control signals are sent to the main supply / exhaust actuator or the backup supply / exhaust actuator only based on the pressure data collected by the non-malfunctioning backup pressure sensor or the main pressure sensor.

[0021] Preferably, both the No. 1 electric actuator self-holding circuit and the No. 2 electric actuator self-holding circuit include a manual / automatic switch button ZT1, a No. 1 normally open button SB1, a No. 4 normally closed button SB2, a No. 2 normally open button SB3, a No. 3 normally closed button SB4, a No. 1 intermediate relay, a No. 2 intermediate relay, a No. 3 intermediate relay, a No. 4 intermediate relay, a No. 5 intermediate relay, a No. 6 intermediate relay, a No. 7 intermediate relay, a No. 1 AC contactor, and a No. 2 AC contactor.

[0022] The positive terminal of the power supply is simultaneously connected to one end of the manual / automatic selector switch ZT1, one end of the normally closed contact KA1-1 of intermediate relay No. 1, one end of the normally open contact KA1-2 of intermediate relay No. 1, one end of the normally closed contact KA1-3 of intermediate relay No. 1, one end of the normally open contact KA1-4 of intermediate relay No. 1, one end of the normally open contact KM01-3 of AC contactor No. 1, and one end of the normally open contact KM02-3 of AC contactor No. 2. The other end of the manual / automatic selector switch ZT1 is connected to one end of the coil KA1 of intermediate relay No. 1. The other end of the normally closed contact KA1-1 of intermediate relay No. 1 is simultaneously connected to one end of the normally open button SB1 of intermediate relay No. 1 and one end of the normally open contact KM01-1 of AC contactor No. 1. The other end of the normally open button SB1 of intermediate relay No. 1 is simultaneously connected to... One end of the No. 4 normally closed pushbutton SB2 is connected to the other end of the normally open contact KM01-1 of the No. 1 AC contactor. The other end of the No. 4 normally closed pushbutton SB2 is also connected to one end of the coil KA4 of the No. 4 intermediate relay and one end of the normally closed contact KA3-1 of the No. 3 intermediate relay. The other end of the normally closed contact KA3-1 of the No. 3 intermediate relay is also connected to one end of the normally open contact KA2-1 of the No. 2 intermediate relay and one end of the normally open contact KM01-2 of the No. 1 AC contactor. The other end of the normally open contact KA2-1 of the No. 2 intermediate relay and the other end of the normally open contact KM01-2 of the No. 1 AC contactor are both connected to the other end of the normally open contact KA1-2 of the No. 1 intermediate relay. The other end of the coil KA4 of the No. 4 intermediate relay is connected to one end of the coil KM01 of the No. 1 AC contactor.

[0023] The other end of the normally closed contact KA1-3 of intermediate relay No. 1 is simultaneously connected to one end of normally open pushbutton SB3 (No. 2) and one end of normally open contact KM02-1 of AC contactor No. 2. The other end of normally open pushbutton SB3 (No. 2) is simultaneously connected to one end of normally closed pushbutton SB4 (No. 3) and one end of normally open contact KM02-1 of AC contactor No. 2. The other end of normally closed pushbutton SB4 (No. 3) is simultaneously connected to one end of coil KA7 of intermediate relay No. 7 and one end of normally closed contact KA6-1 of intermediate relay No. 6. The other end of the normally closed contact KA6-1 of the No. 5 intermediate relay is connected to one end of the normally open contact KA5-1 of the No. 5 intermediate relay and one end of the normally open contact KM02-2 of the No. 2 AC contactor. The other end of the normally open contact KA5-1 of the No. 5 intermediate relay and the other end of the normally open contact KM02-2 of the No. 2 AC contactor are both connected to the other end of the normally open contact KA1-4 of the No. 1 intermediate relay. The other end of the coil KA7 of the No. 7 intermediate relay is connected to one end of the coil KM02 of the No. 2 AC contactor.

[0024] The other end of the normally open contact KM01-3 of AC contactor No. 1 is connected to one input terminal of an electric valve. The other end of the normally open contact KM02-3 of AC contactor No. 2 is connected to the other input terminal of an electric valve. The output terminal of an electric valve, the other end of the coil KA1 of intermediate relay No. 1, the other end of the coil KM01 of AC contactor No. 1, and the other end of the coil KM02 of AC contactor No. 2 are all connected to the power supply ground.

[0025] The main controller's start control signal is connected to one end of the coil KA2 of intermediate relay number two.

[0026] The start / stop signal of the main controller is connected to one end of the coil KA3 of intermediate relay No. 3.

[0027] The main controller's shutdown control signal is connected to one end of the coil KA5 of intermediate relay No. 5.

[0028] The main controller's shutdown signal is connected to one end of the coil KA6 of intermediate relay number six.

[0029] The other end of coil KA2 of intermediate relay No. 2, the other end of coil KA3 of intermediate relay No. 3, the other end of coil KA5 of intermediate relay No. 5, the other end of coil KA6 of intermediate relay No. 6, and the negative terminal of the main controller power supply are all connected to the negative terminal of the power supply; the positive terminal of the main controller power supply is connected to the positive terminal of the power supply.

[0030] Preferably, the device further includes a backup controller;

[0031] The backup controller is used to take over the right to send control signals from the main controller after detecting a failure or malfunction of the main controller, so as to control the main fan or backup fan, main digital electric actuator or backup digital electric actuator, and analog electric actuator to continue to operate.

[0032] Preferably, there are four specific methods for detecting a fault or failure in the main controller:

[0033] The first type:

[0034] A heartbeat signal channel is established between the main controller and the backup controller. The main controller periodically sends a heartbeat signal to the backup controller. The backup controller detects the arrival time of the heartbeat signal. If the arrival time of the heartbeat signal exceeds the set time, it determines that the main controller has failed or malfunctioned.

[0035] The second type:

[0036] A two-way communication link is established between the main controller and the backup controller. The backup controller periodically sends a detection signal to the main controller. If the backup controller does not receive a response from the main controller, it determines that the main controller has failed or is faulty.

[0037] The third type:

[0038] A power detection channel is established between the main controller and the backup controller. The backup controller detects the power status of the main controller. If the main controller's power failure is detected, the main controller is determined to be faulty or malfunctioning.

[0039] The fourth type:

[0040] An I / O module status detection channel is established between the main controller and the backup controller. The backup controller detects the I / O module status of the main controller. If the backup controller detects that the I / O module of the main controller has failed, it determines that the main controller has failed or is faulty.

[0041] Preferably, the device further includes an intermediate signal relay.

[0042] The backup controller is used to trigger an intermediate signal relay to switch contacts when the main controller fails or malfunctions. This switches the contacts that connect the main self-holding inverter or the backup self-holding inverter to the main controller to the contacts that connect the main self-holding inverter or the backup self-holding inverter to the backup controller.

[0043] Preferably, the device further includes a central control room display terminal and an alarm device;

[0044] If the main controller or backup controller detects a fault in any of the main pressure sensor, backup pressure sensor, main fan, or backup fan, it sends an alarm signal to the central control room display terminal, triggering the alarm device.

[0045] Preferably, there are two main switching electric actuators and two standby switching electric actuators.

[0046] Each main fan is equipped with a main switch electric actuator on each side;

[0047] Each standby fan is equipped with a standby switch electric actuator on each side;

[0048] The device also includes a switching electric actuator for a high-efficiency air filter unit, with one switching electric actuator for each high-efficiency air filter unit installed on both sides of each high-efficiency air filter unit in the air supply duct and exhaust duct.

[0049] Preferably, the analog electric actuator is current-type, with a current signal of 4mA-20mA.

[0050] The beneficial effects of this invention are:

[0051] 1. This application includes frequency converters with signal-off self-holding function installed in both the supply and exhaust ducts. When the main controller is short-circuited or fails, the self-holding signal generator inside the frequency converter with self-holding function will immediately issue a self-holding signal. This signal will maintain the last frequency of the output frequency converter, so that the fan continues to supply and exhaust air, and the laboratory always maintains a negative pressure environment.

[0052] 2. A dual-contact self-holding circuit (electric actuator self-holding circuit) is set up for the electric actuator. In the event of controller failure or loss of control signal, the main switch electric actuator can maintain its original open state, continuously ensure the unobstructed flow of laboratory air supply and exhaust ducts, maintain the negative pressure environment of the laboratory, and always maintain the safe operation of the laboratory.

[0053] 3. Compared with the control system provided in existing high-level biosafety laboratories, this application adds redundant pressure sensors (backup pressure sensors) to the supply and exhaust ducts. When the main pressure sensor fails, the backup pressure sensor still sends pressure data to the main controller, so that the main controller still has a control target to ensure that the self-holding frequency converter continues to output signals, so that the fan continues to run, thereby maintaining the negative pressure in the laboratory.

[0054] 4. This application also includes a backup self-holding frequency converter and a backup fan. When the fan fails, the backup self-holding frequency converter is used to control the operation of the backup fan to maintain air supply and exhaust, and to continue to provide negative pressure to the laboratory.

[0055] 5. This application also includes a backup controller. The backup controller monitors the signal of the main controller in real time. Once the main controller fails or malfunctions, it seamlessly switches to the backup control unit. The backup controller takes over from the main controller to continue controlling the operation of the main fan or backup fan, the main switch electric actuator or backup switch electric actuator, and the analog electric actuator, so that all equipment operates without interruption and the negative pressure environment of the laboratory is always maintained. Attached Figure Description

[0056] Figure 1 A topology diagram of a self-holding device used in high-level biosafety laboratories;

[0057] Figure 2 Signal switching diagram between the main control unit and the backup control unit;

[0058] Figure 3 This is a schematic diagram of the redundant fan, redundant electric actuator, and redundant self-holding frequency converter in a redundant control system.

[0059] Figure 4 Electrical schematic diagram of a self-holding circuit for a two-contact electric actuator;

[0060] Figure 5 Main circuit diagram. Detailed Implementation

[0061] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0062] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0063] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0064] Example 1:

[0065] Reference Figure 1 The self-holding device for a high-level biosafety laboratory in this embodiment includes a main controller, an analog electric actuator, a main pressure sensor, a main air supply actuator, and a main exhaust actuator.

[0066] Both the main air supply actuator and the main exhaust actuator include a self-holding circuit for the No. 1 electric actuator, a main switching electric actuator, a main self-holding frequency converter, and a main fan;

[0067] The main pressure sensors installed on the air supply duct and the air exhaust duct are used to collect pressure data of the air supply duct and the air exhaust duct respectively, and send them to the main controller.

[0068] The main controller is used to receive pressure data from the air supply duct and simultaneously send control signals to the main air supply actuator installed in the air supply duct and send current signals to the analog electric actuator installed in the air supply duct; it is also used to receive pressure data from the exhaust duct and simultaneously send control signals to the main exhaust actuator installed in the exhaust duct and send current signals to the analog electric actuator installed in the exhaust duct. The control signals include simultaneously sending a frequency control signal to the main self-holding frequency converter and a switching control signal to the self-holding circuit of the first electric actuator.

[0069] Each main self-holding frequency converter is used to control the speed of the corresponding main fan after receiving the frequency control signal. When the main controller interrupts the output of the frequency control signal, it sends a self-holding signal to the corresponding main fan to maintain the current speed of the corresponding main fan.

[0070] Each No. 1 electric actuator self-holding circuit is used to control the electric valve on the corresponding main switch electric actuator to be open or closed after receiving the switch control signal. When the electric valve is in the open state and the main controller stops outputting the switch control signal, the electric valve is kept in the open state.

[0071] Each analog electric actuator is used to control the opening degree of the electric valve on the analog electric actuator after receiving a current signal. When the current signal is lost, it controls the corresponding electric valve to maintain the current opening degree.

[0072] When a short circuit occurs inside the control cabinet, the fuse blows, and the main controller inside the cabinet is de-energized. This causes all pressure sensors, electric actuators (both digital and analog), and frequency converters (main and standby self-holding frequency converters) to lose control signals, resulting in a complete failure of the control circuit for the ventilation and air conditioning unit (main fan). In this situation, the self-holding circuit of the electric actuators will remain open even without a signal, and the self-holding frequency converter will immediately send a self-holding signal upon signal loss, causing the frequency converter to continue operating at its last output frequency, ensuring continuous air supply and exhaust. Simultaneously, an alarm signal is sent to the central control room display terminal, triggering the alarm device and prompting operation and maintenance personnel to promptly investigate the circuit fault and restore power to the control cabinet. Therefore, even if the control circuit fails during a short circuit in the control cabinet, the ventilation and air conditioning unit can still continuously guarantee the air supply and exhaust volume and the negative pressure environment within the laboratory.

[0073] The preferred redundant structure for maintaining air supply and exhaust in the event of a main fan failure is illustrated by the backup air supply actuator and backup exhaust actuator further included in this embodiment.

[0074] Both the standby air supply actuator and the standby air exhaust actuator include a self-holding circuit for the No. 2 electric actuator, a standby switch quantity electric actuator, a standby self-holding frequency converter, and a standby fan;

[0075] The main fan and standby fan in the air supply duct and exhaust duct are installed in parallel.

[0076] The main switch electric actuator is installed on the main fan side, and the standby switch electric actuator is installed on the standby fan side;

[0077] The main controller is also used to switch the control of the main self-holding frequency converter to the control of the standby self-holding frequency converter when the main self-holding frequency converter detects a fault in the corresponding main fan. The standby self-holding frequency converter controls the speed of the corresponding standby fan, and the standby switch quantity electric actuator is controlled to open or close through the self-holding circuit of the second electric actuator.

[0078] The preferred redundancy structure set up so that the main controller can still receive pressure data when the main pressure sensor fails is illustrated by the backup pressure sensor further included in this embodiment.

[0079] The main controller is also used to take the average pressure of the main pressure sensor and the backup pressure sensor on the air supply duct as the pressure data of the air supply duct; and to take the average pressure of the main pressure sensor and the backup pressure sensor on the exhaust duct as the pressure data of the exhaust duct.

[0080] It is also used to determine that the main pressure sensor or the backup pressure sensor has malfunctioned when the difference between the pressure data of the main pressure sensor or the backup pressure sensor and the set value is greater than the preset difference. In this case, control signals are sent to the main supply / exhaust actuator or the backup supply / exhaust actuator only based on the pressure data collected by the non-malfunctioning backup pressure sensor or the main pressure sensor.

[0081] Because this application is equipped with a backup pressure sensor, when the main pressure sensor on the supply and exhaust duct fails, the backup sensor will send the collected data to the main controller, so that the main controller still has a control target to ensure that the self-holding frequency converter continues to output a signal, so that the fan continues to run, and thus the negative pressure in the laboratory is maintained.

[0082] The preferred structures of the first electric actuator self-holding circuit and the second electric actuator self-holding circuit, which are further included in this embodiment, will be described using them as examples.

[0083] Both the No. 1 electric actuator self-holding circuit and the No. 2 electric actuator self-holding circuit include manual / automatic switch button ZT1, No. 1 normally open button SB1, No. 4 normally closed button SB2, No. 2 normally open button SB3, No. 3 normally closed button SB4, No. 1 intermediate relay, No. 2 intermediate relay, No. 3 intermediate relay, No. 4 intermediate relay, No. 5 intermediate relay, No. 6 intermediate relay, No. 7 intermediate relay, No. 1 AC contactor, and No. 2 AC contactor;

[0084] The positive terminal of the power supply is simultaneously connected to one end of the manual / automatic selector switch ZT1, one end of the normally closed contact KA1-1 of intermediate relay No. 1, one end of the normally open contact KA1-2 of intermediate relay No. 1, one end of the normally closed contact KA1-3 of intermediate relay No. 1, one end of the normally open contact KA1-4 of intermediate relay No. 1, one end of the normally open contact KM01-3 of AC contactor No. 1, and one end of the normally open contact KM02-3 of AC contactor No. 2. The other end of the manual / automatic selector switch ZT1 is connected to one end of the coil KA1 of intermediate relay No. 1. The other end of the normally closed contact KA1-1 of intermediate relay No. 1 is simultaneously connected to one end of the normally open button SB1 of intermediate relay No. 1 and one end of the normally open contact KM01-1 of AC contactor No. 1. The other end of the normally open button SB1 of intermediate relay No. 1 is simultaneously connected to... One end of the No. 4 normally closed pushbutton SB2 is connected to the other end of the normally open contact KM01-1 of the No. 1 AC contactor. The other end of the No. 4 normally closed pushbutton SB2 is also connected to one end of the coil KA4 of the No. 4 intermediate relay and one end of the normally closed contact KA3-1 of the No. 3 intermediate relay. The other end of the normally closed contact KA3-1 of the No. 3 intermediate relay is also connected to one end of the normally open contact KA2-1 of the No. 2 intermediate relay and one end of the normally open contact KM01-2 of the No. 1 AC contactor. The other end of the normally open contact KA2-1 of the No. 2 intermediate relay and the other end of the normally open contact KM01-2 of the No. 1 AC contactor are both connected to the other end of the normally open contact KA1-2 of the No. 1 intermediate relay. The other end of the coil KA4 of the No. 4 intermediate relay is connected to one end of the coil KM01 of the No. 1 AC contactor.

[0085] The other end of the normally closed contact KA1-3 of intermediate relay No. 1 is simultaneously connected to one end of normally open pushbutton SB3 (No. 2) and one end of normally open contact KM02-1 of AC contactor No. 2. The other end of normally open pushbutton SB3 (No. 2) is simultaneously connected to one end of normally closed pushbutton SB4 (No. 3) and one end of normally open contact KM02-1 of AC contactor No. 2. The other end of normally closed pushbutton SB4 (No. 3) is simultaneously connected to one end of coil KA7 of intermediate relay No. 7 and one end of normally closed contact KA6-1 of intermediate relay No. 6. The other end of the normally closed contact KA6-1 of the No. 5 intermediate relay is connected to one end of the normally open contact KA5-1 of the No. 5 intermediate relay and one end of the normally open contact KM02-2 of the No. 2 AC contactor. The other end of the normally open contact KA5-1 of the No. 5 intermediate relay and the other end of the normally open contact KM02-2 of the No. 2 AC contactor are both connected to the other end of the normally open contact KA1-4 of the No. 1 intermediate relay. The other end of the coil KA7 of the No. 7 intermediate relay is connected to one end of the coil KM02 of the No. 2 AC contactor.

[0086] The other end of the normally open contact KM01-3 of AC contactor No. 1 is connected to one input terminal of an electric valve. The other end of the normally open contact KM02-3 of AC contactor No. 2 is connected to the other input terminal of an electric valve. The output terminal of an electric valve, the other end of the coil KA1 of intermediate relay No. 1, the other end of the coil KM01 of AC contactor No. 1, and the other end of the coil KM02 of AC contactor No. 2 are all connected to the power supply ground.

[0087] The main controller's start control signal is connected to one end of the coil KA2 of intermediate relay number two.

[0088] The start / stop signal of the main controller is connected to one end of the coil KA3 of intermediate relay No. 3.

[0089] The main controller's shutdown control signal is connected to one end of the coil KA5 of intermediate relay No. 5.

[0090] The main controller's shutdown signal is connected to one end of the coil KA6 of intermediate relay number six.

[0091] The other end of coil KA2 of intermediate relay No. 2, the other end of coil KA3 of intermediate relay No. 3, the other end of coil KA5 of intermediate relay No. 5, the other end of coil KA6 of intermediate relay No. 6, and the negative terminal of the main controller power supply are all connected to the negative terminal of the power supply; the positive terminal of the main controller power supply is connected to the positive terminal of the power supply.

[0092] Typically, the control signal lines of a switching electric actuator are divided into on and off signal lines. In engineering, a relay is usually used to switch an electric actuator on and off. If the electric actuator's control signal is lost and it is under power, the relay will change from a normally open to a normally closed contact, causing the electric actuator to change from the on to the off state. This can disrupt the smooth flow of ventilation, leading to serious consequences such as pressure loss in the laboratory. Therefore, a dual-relay, dual-contact self-holding circuit control is used to ensure that the electric actuator remains in its original state even when the signal is lost. Furthermore, it has on-site manual / automatic functions. In special circumstances, if the control circuit fails, it can switch to manual operation on-site, enabling rapid local opening and closing of the electric actuator.

[0093] Figure 5 The circuit outputs two types of power: one is a 24V power supply, used for... Figure 3 The electric valves, main controller, and backup controller on both sides of the blower are powered by one power source; the other is a 220V power source used to power the electric valves on both sides of the high-efficiency filter unit.

[0094] The redundant control method is illustrated by taking the backup controller further included in this embodiment.

[0095] The backup controller is used to take over the right to send control signals from the main controller after detecting a failure or malfunction of the main controller, so as to control the main fan or backup fan, main digital electric actuator or backup digital electric actuator, and analog electric actuator to continue to operate.

[0096] Since maintaining the negative pressure environment in the laboratory mainly relies on the control signals transmitted from the main controller to the frequency converter, the frequency converter converts the voltage control signal into frequency control to control the speed of the fan. Figure 3 In the diagram, 1-8 are electric actuators (on / off electric actuators) for the fan and damper; 9-12 are electric actuators (on / off electric actuators) for the bio-sealed valve of the HEPA filter unit; 13-14 are electric actuators (analog electric actuators) for the variable air volume valve that adjusts the negative pressure in the laboratory; 15-18 are pressure sensors (main pressure sensor and backup pressure sensor) for the main supply and exhaust ducts of the ventilation and air conditioning unit; 19-22 are the supply and exhaust fans (main fan and backup fan) of the ventilation and air conditioning unit; and 23-26 are frequency converters with signal interruption self-holding function (self-holding frequency converters). During normal operation, 2, 4, 6, 8, and 9-14 are all in the open state, while 20 and 22 are in automatic operation state. In the event of the following faults, the redundant control system can ensure that the laboratory remains in a negative pressure environment.

[0097] Fault 1: Supply (exhaust) fan failure. When 20 (22) is in operation and a failure suddenly occurs, 23 (26) will send a fault signal to the main controller. The main controller will automatically switch the supply / exhaust fan to 19 (21) to continue operation. At the same time, an alarm signal will be sent to the central control room display terminal, triggering the alarm device. Relevant personnel will repair or replace the fan to restore it to redundant status.

[0098] Fault 2: Faulty pressure sensor in the main supply (exhaust) air duct. During the operation of the ventilation and air conditioning unit, pressure data from sensors 15 and 16 (or 17 and 18) are transmitted to the main controller. The main controller calculates the average value of the two sensors as the target value for adjusting the supply / exhaust fan frequency. When the difference between the data collected by sensor 15 and the set value exceeds 100, the main control unit determines that a fault has occurred and continues to control the frequency converter's adjustment based on the value collected by sensor 16. Simultaneously, an alarm signal is sent to the central control room display terminal, triggering the alarm device. Relevant personnel then repair or replace the sensor to restore it to redundant status.

[0099] Fault 3: Short circuit inside the control cabinet, control unit malfunction. Figure 4This is the self-holding circuit of the electric actuator. ZT1 is the manual / automatic switch button. In automatic operation, ZTI closes, KA1 is energized, and the control circuit is in automatic mode. At this time, the normally open contact KA1-2 of KA1 closes. The main control circuit then sends an open signal through Q0.0, energizing KA2. At this time, the normally open contact KA2-1 of KA2 closes, KM01 is energized and forms a self-locking circuit, and the normally open contact KM01-3 of KM01 closes, opening the electric valve. Simultaneously, in special circumstances, the control circuit can be switched to manual mode as needed, enabling the electric actuator to switch on and off. Disconnecting ZTI switches to manual mode. At this time, KA1 is de-energized, and pressing SB1 energizes KM01, forming a self-locking circuit. The normally open contact KM01-3 of KM01 closes, opening the electric valve. The closing process of the electric actuator is the same as the opening process.

[0100] If a short circuit occurs inside the control cabinet, causing the control unit to fail, KA2 will lose power. The normally open contact KA2-1 will return to the open state. However, because a self-locking circuit has been formed, KM01 will remain energized, and the electric actuator in the self-holding circuit will remain in its original state. At this time, Figure 3 1-12 in the diagram are all switching electric actuators. Through their own self-holding circuits, they can maintain their original state and ensure the smooth flow of air supply and exhaust channels.

[0101] like Figure 1 As shown, the main control unit includes a main controller and a main I / O module, while the backup control unit includes a standby controller and a slave I / O module. Both the main and standby controllers can independently control the ventilation and air conditioning unit (fan). These two control units are identical; the signal connecting to the terminal equipment is split in two via a signal splitter, connected to the main I / O module and the slave I / O module respectively. When the main controller or main I / O module fails or goes offline, the standby controller takes over control and continues to control the ventilation and air conditioning unit, ensuring its continuous operation. Simultaneously, it transmits alarm information to the central control room display terminal via Ethernet, and the alarm device issues an audible and visual alarm. When the operation and maintenance personnel restore the main controller or main I / O module to normal, the main controller regains control. The switching between the main and standby control units does not affect the continuous operation of the ventilation and air conditioning unit. Therefore, during normal operation, the main control unit is responsible for controlling the ventilation and air conditioning system, while the backup control unit is in standby mode. If the main control unit fails or goes offline, the backup control unit takes over the control of the system to ensure the ventilation and air conditioning system continues to operate normally and the negative pressure environment of the laboratory is maintained.

[0102] In dual-machine duplex mode, a bidirectional communication link is established between the main control unit and the backup control unit. The main control unit and the backup control unit communicate via Ethernet using the TCP / IP protocol. This method offers advantages such as high speed, stability, and reliability.

[0103] The preferred method for determining whether the main controller has failed or malfunctioned is illustrated by the method for detecting a fault or malfunction in the main controller further included in this embodiment:

[0104] The first type:

[0105] A heartbeat signal channel is established between the main controller and the backup controller. The main controller periodically sends a heartbeat signal to the backup controller. The backup controller detects the arrival time of the heartbeat signal. If the arrival time of the heartbeat signal exceeds the set time, it determines that the main controller has failed or malfunctioned.

[0106] The second type:

[0107] A two-way communication link is established between the main controller and the backup controller. The backup controller periodically sends a detection signal to the main controller. If the backup controller does not receive a response from the main controller, it determines that the main controller has failed or is faulty.

[0108] The third type:

[0109] A power detection channel is established between the main controller and the backup controller. The backup controller detects the power status of the main controller. If the main controller's power failure is detected, the main controller is determined to be faulty or malfunctioning.

[0110] The fourth type:

[0111] An I / O module status detection channel is established between the main controller and the backup controller. The backup controller detects the I / O module status of the main controller. If the backup controller detects that the I / O module of the main controller has failed, it determines that the main controller has failed or is faulty.

[0112] The preferred method for switching between the main controller and the backup controller will be described using the intermediate signal relay further included in this embodiment:

[0113] The backup controller is used to trigger an intermediate signal relay to switch contacts when the main controller fails or malfunctions. This switches the contacts that connect the main self-holding inverter or the backup self-holding inverter to the main controller to the contacts that connect the main self-holding inverter or the backup self-holding inverter to the backup controller.

[0114] Since all four methods for detecting a fault or failure in the main controller can achieve the switching effect, Figure 2Taking the heartbeat signal detection as an example, let's focus on its specific implementation: A heartbeat signal channel is established between the main controller and the backup controller. The main controller periodically sends a heartbeat signal, which is a 4-20mA current signal. The backup controller detects the arrival time of the heartbeat signal. If it does not receive a heartbeat signal after a certain period, it determines that the main controller has failed or malfunctioned. This method achieves switching through an intermediate signal relay. When the backup control unit does not receive a heartbeat signal for a certain period, the main / backup fault switching point closes, energizing contacts 13 and 14 of the intermediate signal relay. The two sets of contacts switch from 1 and 4 to 5 and 8, and the inverter input signal switches from the main controller to the backup controller. At this time, the backup controller continues to control the ventilation and air conditioning unit, and the switching is complete.

[0115] The preferred handling method for equipment failure will be described using the central control room display terminal and alarm device further included in this embodiment:

[0116] If the main controller or backup controller detects a fault in any of the main pressure sensor, backup pressure sensor, main fan, or backup fan, it sends an alarm signal to the central control room display terminal, triggering the alarm device.

[0117] The preferred positions and quantities are illustrated by the number of main switching electric actuators, backup switching electric actuators, and switching electric actuators in the high-efficiency air filtration unit, which are further defined in this embodiment:

[0118] The number of main switch electric actuators and the number of standby switch electric actuators are two each;

[0119] Each main fan is equipped with a main switch electric actuator on each side;

[0120] Each standby fan is equipped with a standby switch electric actuator on each side;

[0121] The device also includes a switching electric actuator for a high-efficiency air filter unit, with one switching electric actuator for each high-efficiency air filter unit installed on both sides of each high-efficiency air filter unit in the air supply duct and exhaust duct.

[0122] like Figure 3 As shown, electric actuators are installed inside the ventilation and air conditioning unit and in the supply and exhaust air branch ducts. These electric actuators are divided into digital (on / off) electric actuators and analog electric actuators. Digital electric actuators are partially installed at the front and rear ends of the fan, and partially at the front and rear ends of the high-efficiency filter units in the supply and exhaust air branch ducts of the air conditioning unit. Analog electric actuators are installed at the rear end of the high-efficiency filter units in the supply and exhaust air branch ducts of the air conditioning unit and are used to adjust the negative pressure gradient in the laboratory.

[0123] When using HEPA filter units outside the laboratory protected area, their robust structure must withstand pressures up to 2500 Pa. The overall airtightness of the HEPA filter unit should ensure that, with all passages closed and the temperature within the chamber maintained at the upper limit of the design range, the amount of air leaking per minute should not exceed 0.1% of the net volume of the chamber when the air pressure is maintained at 1000 Pa. Because the HEPA filter unit requires complete sealing, a biosafety shut-off valve must be installed. The opening and closing of the biosafety shut-off valve is achieved through a switching electric actuator.

[0124] If two layers of high-efficiency air filters are installed in the exhaust duct, then four on / off electric actuators should be installed. Figure 3 If one layer of high-efficiency air filter unit is installed in the air supply duct, two on / off electric actuators are required; if two layers of high-efficiency air filter unit are installed in the exhaust duct, four on / off electric actuators are required.

[0125] The reason for installing switch-type electric actuators on both sides of the fan is that when the main fan fails and the standby fan is running, the switch-type electric actuators on both sides of the main fan can be turned off, the fan door of the air conditioning unit can be opened, the faulty fan can be repaired, and the operation of the standby fan will not be affected.

[0126] This embodiment further defines the type of analog electric actuator:

[0127] The analog electric actuator is current-type, with a current signal of 4mA - 20mA.

[0128] For the 13-14 analog electric actuator, which uses a 4mA-20mA current signal and has a signal-off self-holding function, when the control unit fails and the signal is lost, the current signal received by 13-14 will be 0mA, which is automatically identified as a signal loss state, and its opening degree will remain unchanged. Therefore, 13-14 will maintain its current position.

[0129] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A self-holding device for use in high-level biosafety laboratories, characterized in that, Main controller, analog electric actuator, main pressure sensor, main air supply actuator and main exhaust actuator; Both the main air supply actuator and the main exhaust actuator include a self-holding circuit for the No. 1 electric actuator, a main switching electric actuator, a main self-holding frequency converter, and a main fan; The main pressure sensors installed on the air supply duct and the air exhaust duct are used to collect pressure data of the air supply duct and the air exhaust duct respectively, and send them to the main controller. The main controller is used to receive pressure data from the air supply duct and simultaneously send control signals to the main air supply actuator installed in the air supply duct and send current signals to the analog electric actuator installed in the air supply duct; it is also used to receive pressure data from the exhaust duct and simultaneously send control signals to the main exhaust actuator installed in the exhaust duct and send current signals to the analog electric actuator installed in the exhaust duct. The control signals include simultaneously sending a frequency control signal to the main self-holding frequency converter and a switching control signal to the self-holding circuit of the first electric actuator. Each main self-holding frequency converter is used to control the speed of the corresponding main fan after receiving the frequency control signal. When the main controller interrupts the output of the frequency control signal, it sends a self-holding signal to the corresponding main fan to maintain the current speed of the corresponding main fan. Each No. 1 electric actuator self-holding circuit is used to control the electric valve on the corresponding main switch electric actuator to be open or closed after receiving the switch control signal. When the electric valve is in the open state and the main controller stops outputting the switch control signal, the electric valve is kept in the open state. Each analog electric actuator is used to control the opening degree of the electric valve on the analog electric actuator after receiving a current signal. When the current signal is lost, it controls the corresponding electric valve to maintain the current opening degree. Both the No. 1 electric actuator self-holding circuit and the No. 2 electric actuator self-holding circuit include manual / automatic switch button ZT1, No. 1 normally open button SB1, No. 4 normally closed button SB2, No. 2 normally open button SB3, No. 3 normally closed button SB4, No. 1 intermediate relay, No. 2 intermediate relay, No. 3 intermediate relay, No. 4 intermediate relay, No. 5 intermediate relay, No. 6 intermediate relay, No. 7 intermediate relay, No. 1 AC contactor, and No. 2 AC contactor; The positive terminal of the power supply is simultaneously connected to one end of the manual / automatic selector switch ZT1, one end of the normally closed contact KA1-1 of intermediate relay No. 1, one end of the normally open contact KA1-2 of intermediate relay No. 1, one end of the normally closed contact KA1-3 of intermediate relay No. 1, one end of the normally open contact KA1-4 of intermediate relay No. 1, one end of the normally open contact KM01-3 of AC contactor No. 1, and one end of the normally open contact KM02-3 of AC contactor No.

2. The other end of the manual / automatic selector switch ZT1 is connected to one end of the coil KA1 of intermediate relay No.

1. The other end of the normally closed contact KA1-1 of intermediate relay No. 1 is simultaneously connected to one end of the normally open button SB1 of intermediate relay No. 1 and one end of the normally open contact KM01-1 of AC contactor No.

1. The other end of the normally open button SB1 of intermediate relay No. 1 is simultaneously connected to... One end of the No. 4 normally closed pushbutton SB2 is connected to the other end of the normally open contact KM01-1 of the No. 1 AC contactor. The other end of the No. 4 normally closed pushbutton SB2 is also connected to one end of the coil KA4 of the No. 4 intermediate relay and one end of the normally closed contact KA3-1 of the No. 3 intermediate relay. The other end of the normally closed contact KA3-1 of the No. 3 intermediate relay is also connected to one end of the normally open contact KA2-1 of the No. 2 intermediate relay and one end of the normally open contact KM01-2 of the No. 1 AC contactor. The other end of the normally open contact KA2-1 of the No. 2 intermediate relay and the other end of the normally open contact KM01-2 of the No. 1 AC contactor are both connected to the other end of the normally open contact KA1-2 of the No. 1 intermediate relay. The other end of the coil KA4 of the No. 4 intermediate relay is connected to one end of the coil KM01 of the No. 1 AC contactor. The other end of the normally closed contact KA1-3 of intermediate relay No. 1 is simultaneously connected to one end of normally open pushbutton SB3 (No. 2) and one end of normally open contact KM02-1 of AC contactor No.

2. The other end of normally open pushbutton SB3 (No. 2) is simultaneously connected to one end of normally closed pushbutton SB4 (No. 3) and one end of normally open contact KM02-1 of AC contactor No.

2. The other end of normally closed pushbutton SB4 (No. 3) is simultaneously connected to one end of coil KA7 of intermediate relay No. 7 and one end of normally closed contact KA6-1 of intermediate relay No.

6. The other end of the normally closed contact KA6-1 of the No. 5 intermediate relay is connected to one end of the normally open contact KA5-1 of the No. 5 intermediate relay and one end of the normally open contact KM02-2 of the No. 2 AC contactor. The other end of the normally open contact KA5-1 of the No. 5 intermediate relay and the other end of the normally open contact KM02-2 of the No. 2 AC contactor are both connected to the other end of the normally open contact KA1-4 of the No. 1 intermediate relay. The other end of the coil KA7 of the No. 7 intermediate relay is connected to one end of the coil KM02 of the No. 2 AC contactor. The other end of the normally open contact KM01-3 of AC contactor No. 1 is connected to one input terminal of an electric valve. The other end of the normally open contact KM02-3 of AC contactor No. 2 is connected to the other input terminal of an electric valve. The output terminal of an electric valve, the other end of the coil KA1 of intermediate relay No. 1, the other end of the coil KM01 of AC contactor No. 1, and the other end of the coil KM02 of AC contactor No. 2 are all connected to the power supply ground. The main controller's start control signal is connected to one end of the coil KA2 of intermediate relay number two. The start / stop signal of the main controller is connected to one end of the coil KA3 of intermediate relay No.

3. The main controller's shutdown control signal is connected to one end of the coil KA5 of intermediate relay No.

5. The main controller's shutdown signal is connected to one end of the coil KA6 of intermediate relay number six. The other end of coil KA2 of intermediate relay No. 2, the other end of coil KA3 of intermediate relay No. 3, the other end of coil KA5 of intermediate relay No. 5, the other end of coil KA6 of intermediate relay No. 6, and the negative terminal of the main controller power supply are all connected to the negative terminal of the power supply; the positive terminal of the main controller power supply is connected to the positive terminal of the power supply.

2. The self-holding device for a high-level biosafety laboratory according to claim 1, characterized in that, The device also includes a backup air supply actuator and a backup air exhaust actuator; Both the standby air supply actuator and the standby air exhaust actuator include a self-holding circuit for the No. 2 electric actuator, a standby switch quantity electric actuator, a standby self-holding frequency converter, and a standby fan; The main fan and standby fan in the air supply duct and exhaust duct are installed in parallel. The main switch electric actuator is installed on the main fan side, and the standby switch electric actuator is installed on the standby fan side; The main controller is also used to switch the control of the main self-holding frequency converter to the control of the standby self-holding frequency converter when the main self-holding frequency converter detects a fault in the corresponding main fan. The standby self-holding frequency converter controls the speed of the corresponding standby fan, and the standby switch quantity electric actuator is controlled to open or close through the self-holding circuit of the second electric actuator.

3. The self-holding device for a high-level biosafety laboratory according to claim 2, characterized in that, The device also includes a backup pressure sensor; The main controller is also used to take the average pressure of the main pressure sensor and the backup pressure sensor on the air supply duct as the pressure data of the air supply duct; and to take the average pressure of the main pressure sensor and the backup pressure sensor on the exhaust duct as the pressure data of the exhaust duct. It is also used to determine that the main pressure sensor or the backup pressure sensor has malfunctioned when the difference between the pressure data of the main pressure sensor or the backup pressure sensor and the set value is greater than the preset difference. In this case, control signals are sent to the main supply / exhaust actuator or the backup supply / exhaust actuator only based on the pressure data collected by the non-malfunctioning backup pressure sensor or the main pressure sensor.

4. The self-holding device for a high-level biosafety laboratory according to claim 1, characterized in that, The device also includes a backup controller; The backup controller is used to take over the right to send control signals from the main controller after detecting a failure or malfunction of the main controller, so as to control the main fan or backup fan, main digital electric actuator or backup digital electric actuator, and analog electric actuator to continue to operate.

5. The self-holding device for a high-level biosafety laboratory according to claim 4, characterized in that, There are four specific methods to detect a fault or failure in the main controller: The first type: A heartbeat signal channel is established between the main controller and the backup controller. The main controller periodically sends a heartbeat signal to the backup controller. The backup controller detects the arrival time of the heartbeat signal. If the arrival time of the heartbeat signal exceeds the set time, it determines that the main controller has failed or malfunctioned. The second type: A two-way communication link is established between the main controller and the backup controller. The backup controller periodically sends a detection signal to the main controller. If the backup controller does not receive a response from the main controller, it determines that the main controller has failed or is faulty. The third type: A power detection channel is established between the main controller and the backup controller. The backup controller detects the power status of the main controller. If the main controller's power failure is detected, the main controller is determined to be faulty or malfunctioning. The fourth type: An I / O module status detection channel is established between the main controller and the backup controller. The backup controller detects the I / O module status of the main controller. If the backup controller detects that the I / O module of the main controller has failed, it determines that the main controller has failed or is faulty.

6. The self-holding device for a high-level biosafety laboratory according to claim 5, characterized in that, The device also includes an intermediate signal relay. The backup controller is used to trigger an intermediate signal relay to switch contacts when the main controller fails or malfunctions. This switches the contacts that connect the main self-holding inverter or the backup self-holding inverter to the main controller to the contacts that connect the main self-holding inverter or the backup self-holding inverter to the backup controller.

7. The self-holding device for a high-level biosafety laboratory according to claim 6, characterized in that, The device also includes a central control room display terminal and an alarm device; If the main controller or backup controller detects a fault in any of the main pressure sensor, backup pressure sensor, main fan, or backup fan, it sends an alarm signal to the central control room display terminal, triggering the alarm device.

8. The self-holding device for a high-level biosafety laboratory according to claim 7, characterized in that, The number of main switch electric actuators and the number of standby switch electric actuators are two each; Each main fan is equipped with a main switch electric actuator on each side; Each standby fan is equipped with a standby switch electric actuator on each side; The device also includes a switching electric actuator for a high-efficiency air filter unit, with one switching electric actuator for each high-efficiency air filter unit installed on both sides of each high-efficiency air filter unit in the air supply duct and exhaust duct.

9. The self-holding device for a high-level biosafety laboratory according to claim 1, characterized in that, The analog electric actuator is current-type, with a current signal of 4mA-20mA.

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