A dual valve timing isolation control system and method of controlling the same

Abstract

The application belongs to the technical field of mass spectrum electric control, and particularly relates to a double-valve time sequence isolation control system and a control method thereof. The system comprises a first electromagnetic valve connected between a gas supply source and a buffer cavity, a second electromagnetic valve connected between the buffer cavity and a target cavity, and a control module electrically connected with the two electromagnetic valves. In operation, the control module opens the first electromagnetic valve in response to a trigger signal to enable the gas supply source to fill the buffer cavity with gas, and then closes the first electromagnetic valve to isolate the buffer cavity from the gas supply source when a preset filling condition is reached. Subsequently, a second driving signal is generated to drive the second electromagnetic valve to perform high-frequency on-off action at a preset frequency and a preset duty cycle, so as to release the gas in the buffer cavity to the target cavity in batches and in small amounts. The application realizes the batched and small-amount introduction of the gas through the cooperation of the double valves and the PWM high-frequency on-off control, effectively avoids the disturbance to the environment of the target cavity caused by the instantaneous large amount of gas, and has a simple circuit structure and reliable operation.

Description

Technical Field

[0001] This invention belongs to the field of mass spectrometry electronic control technology, specifically relating to a dual-valve time-sequential isolation control system and its control method. Background Technology

[0002] In mass spectrometry analysis, to calibrate data deviations and improve quantitative analysis accuracy, saturated vapor of an internal standard is typically introduced into the mass spectrometer chamber. Current conventional solutions often use a single-channel solenoid valve to directly control the introduction of internal standard vapor into the mass spectrometer chamber. This method has significant drawbacks: first, direct on / off control with a single-channel valve cannot precisely regulate the introduction rate and volume of internal standard vapor, easily leading to a sudden surge of large amounts; second, direct on / off operation causes drastic fluctuations in the vacuum environment of the mass spectrometer chamber, severely disrupting the high-vacuum operating environment of the mass spectrometer, thus affecting the stability and accuracy of the detection data, and even causing damage to the equipment hardware.

[0003] While some current solutions employ a dual-solenoid valve step-by-step control approach, none have precisely adapted the solenoid valve drive control method and on / off timing. In existing dual-valve solutions, the two solenoid valves are typically only controlled by simple series connection, failing to achieve fine-tuning of the vapor release rate within the buffer chamber. The internal standard vapor still enters the mass spectrometer chamber in a relatively concentrated manner, resulting in unsatisfactory vacuum environment protection. Furthermore, existing control circuits generally lack specific protection designs for the inductive load of the solenoid valves. The reverse induced electromotive force generated during frequent on / off cycles of the solenoid valves can easily cause cumulative damage to the front-end control devices, affecting the long-term operational reliability of the system. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-valve time-sequential isolation control system and its control method to solve the technical problems of difficulty in controlling the amount of steam introduced and easy disturbance of the vacuum environment of the mass spectrometer cavity during the process of introducing internal standard steam in existing mass spectrometers due to the direct on / off of a single valve.

[0005] The present invention achieves the above objectives through the following technical solutions: In a first aspect, the present invention proposes a dual-valve timing isolation control system for introducing gas from a gas supply source into a target cavity via a buffer chamber, comprising: A first solenoid valve is connected between the air supply source and the buffer chamber; A second solenoid valve is connected between the buffer chamber and the target chamber; The control module is electrically connected to the first solenoid valve and the second solenoid valve respectively; The control module responds to an externally input trigger signal and outputs a first drive signal to open the first solenoid valve, allowing the gas supply source to fill the buffer chamber with gas. When a preset filling condition is met, the control module controls the first solenoid valve to close, isolating the buffer chamber from the gas supply source. After confirming that the first solenoid valve is in the closed state, the control module generates a second drive signal, which drives the second solenoid valve to perform high-frequency on / off operations at a preset frequency and preset duty cycle, so as to release the gas in the buffer chamber into the target chamber in batches.

[0006] As a further preferred embodiment, the control module includes a timing control unit and a PWM generation unit; the first drive signal is generated and output by the timing control unit; the second drive signal is generated and output by the PWM generation unit according to a preset frequency and a preset duty cycle.

[0007] As a further preferred embodiment, the control module is electrically connected to the first solenoid valve through a first isolation drive circuit. The first isolation drive circuit includes a first optocoupler, a first switching transistor, and a first relay. The first drive signal is transmitted to the control terminal of the first switching transistor after being isolated by the first optocoupler. The first switching transistor controls the on / off state of the coil of the first relay. The contacts of the first relay are connected to the power supply circuit of the first solenoid valve.

[0008] As a further preferred embodiment, the control module is electrically connected to the second solenoid valve through a second isolation drive circuit, the second isolation drive circuit including a second optocoupler and a second switching transistor; the second drive signal is transmitted to the control terminal of the second switching transistor after being isolated by the second optocoupler, and the second switching transistor is connected in series in the power supply circuit of the second solenoid valve.

[0009] As a further preferred embodiment, both the first and second solenoid valves have freewheeling diodes connected in reverse parallel across their coils to form a discharge circuit for the reverse induced electromotive force at the moment the coils are de-energized.

[0010] As a further preferred embodiment, the system also includes a communication module and an isolated power supply module; the communication module is electrically connected to the control module and is used to receive the trigger signal sent by an external host computer and transmit the trigger signal to the control module; the input terminal of the isolated power supply module is connected to an external power supply, and its output terminal is connected to the power supply ports of the control module and the communication module respectively, so as to achieve power supply isolation.

[0011] Secondly, the present invention proposes a dual-valve time-sequential isolation control method, applied to the dual-valve time-sequential isolation control system as described above, comprising the following steps: After the control module is powered on, it controls both the first solenoid valve and the second solenoid valve to remain in the closed state, thereby isolating the air supply source, the buffer chamber and the target chamber from each other. The control module responds to an externally input trigger signal and outputs a first drive signal to open the first solenoid valve, so that the gas supply source fills the buffer chamber with gas until the preset filling condition is reached. When the preset filling condition is met, the control module controls the first solenoid valve to shut off, thereby isolating the buffer chamber from the air supply source and keeping the buffer chamber isolated from the target chamber. After confirming that the first solenoid valve is in the off state, the control module generates a second drive signal. The second drive signal drives the second solenoid valve to perform high-frequency on / off action at a preset frequency and preset duty cycle, so as to release the gas in the buffer cavity into the target cavity in batches. After the gas in the buffer chamber is completely released, the control module controls the second solenoid valve to close, so that both the first solenoid valve and the second solenoid valve remain closed, and the gas supply source, the buffer chamber and the target chamber are isolated from each other.

[0012] As a further preferred embodiment, the second driving signal is a PWM pulse width modulation signal. By adjusting the size of the preset duty cycle, the on-time of the second solenoid valve in each on-off cycle is controlled to adjust the rate at which the gas in the buffer chamber is released into the target chamber.

[0013] As a further preferred embodiment, the preset charging condition is a preset duration, and the control module starts timing from the moment the first solenoid valve is opened, and controls the first solenoid valve to close when the timing reaches the preset duration.

[0014] Thirdly, the present invention proposes a mass spectrometry internal standard introduction device, including a gas supply source, a buffer chamber, a target chamber, and a dual-valve timing isolation control system as described above; the gas supply source is an internal standard liquid storage container for providing internal standard saturated vapor, the target chamber is a mass spectrometry analysis chamber, and the buffer chamber is an isolation buffer chamber disposed between the internal standard liquid storage container and the mass spectrometry analysis chamber.

[0015] The beneficial effects of this invention are as follows: 1. This invention effectively solves the problem of disturbance to the target cavity environment during gas introduction by employing a timing control strategy of pre-charging, isolation, and pulse release. After the first solenoid valve opens, the gas supply source charges the buffer cavity with gas. Once the preset charging conditions are met, the first solenoid valve immediately closes, completely isolating the buffer cavity from the gas supply source. The pressure from the gas supply source no longer acts on the buffer cavity, and the amount of gas stored in the buffer cavity remains constant. Subsequently, the second solenoid valve operates using a PWM high-frequency on / off mode. Within each on / off cycle, only a tiny time window is opened, releasing the gas stored in the buffer cavity in hundreds to thousands of minute batches. Because the amount of gas released in each batch is extremely small, and sufficient time is allowed for the cavity environment to recover between batches, the pressure or vacuum level of the target cavity will not experience sudden increases or decreases. Taking the mass spectrometer cavity as an example, after adopting the control method of the present invention, the fluctuation range of the cavity vacuum degree during the introduction of internal standard vapor is significantly reduced, and the vacuum recovery time is greatly shortened, which effectively ensures the stability of the high vacuum working environment of the mass spectrometer and avoids the risk of severe fluctuations in the vacuum environment and damage to equipment hardware caused by the instantaneous large influx of gas under the traditional single valve direct-flow method.

[0016] 2. This invention constructs a dual protection architecture combining isolated drive and freewheeling absorption at the hardware circuit level, significantly improving the anti-interference capability and long-term operational reliability of the control circuit when driving inductive loads. The first solenoid valve adopts a three-stage drive structure composed of optocouplers, transistors, and relays, while the second solenoid valve adopts a direct optocoupler drive structure. The two drive methods are designed differently according to the working characteristics of their respective valve bodies, ensuring reliable drive while avoiding the lifespan bottleneck of mechanical relays under high-frequency conditions. Optocoupler isolation completely isolates the digital circuit of the front-end control module from the power circuit of the back-end solenoid valve, preventing surges and electromagnetic interference generated on the power side from being conducted to the control chip. The Schottky freewheeling diodes connected in reverse parallel across the coils of the solenoid valve and relay form a discharge circuit at the moment of power failure of the inductive load, eliminating the risk of high-voltage pulses damaging the switching transistors and the internal transistors of the optocoupler. The isolated power supply module further achieves electrical isolation between the control side and the power side in the power supply path. Combined with the signal isolation of the optocoupler, it forms an architecture with complete isolation in both power supply and signal dimensions, enabling the control module to maintain stable operation in strong electromagnetic interference environments, which is especially suitable for mass spectrometry analysis equipment with high electromagnetic compatibility requirements. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall module structure of the dual-valve timing isolation control system of the present invention; Figure 2 This is a circuit diagram of the first isolation drive circuit and the first solenoid valve of the present invention. Figure 3 This is a circuit diagram of the second isolation drive circuit and the second solenoid valve of the present invention. Figure 4 This is a flowchart of the steps of the dual-valve timing isolation control method of the present invention.

[0018] Figure 1 In the middle: 1. Air supply source; 2. Buffer chamber; 3. Target chamber; 10. First solenoid valve; 20. Second solenoid valve; 30. Control module; 31. Timing control unit; 32. PWM generation unit; 40. First isolation drive circuit; 50. Second isolation drive circuit; 60. Communication module; 70. Isolation power supply module. Detailed Implementation

[0019] The following description provides specific application scenarios and requirements for this specification, intended to enable those skilled in the art to make and use the contents of this specification. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0020] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not restrictive. For example, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” used herein may also include the plural forms. When used in this specification, the terms “comprising,” “including,” and / or “containing” mean that the associated integers, steps, operations, elements, and / or components are present, but do not exclude the presence of one or more other features, integers, steps, operations, elements, components, and / or groups, or that other features, integers, steps, operations, elements, components, and / or groups may be added to the system / method.

[0021] Considering the following description, these and other features of this specification, as well as the operation and function of the related components of the structure, and the economy of assembly and manufacture of the parts, can be significantly improved. All of these form part of this specification with reference to the accompanying drawings. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not drawn to scale.

[0022] The flowcharts used in this specification illustrate operations implemented according to some embodiments of this specification. It should be clearly understood that the operations in the flowcharts may not be implemented in a sequential order. Instead, the operations may be implemented in reverse order or simultaneously. Furthermore, one or more additional operations may be added to the flowcharts. One or more operations may be removed from the flowcharts.

[0023] First Embodiment The following combination Figures 1-3The dual-valve timing isolation control system provided in this embodiment will be described in detail.

[0024] like Figure 1 As shown, this embodiment provides a dual-valve timing isolation control system for introducing gas from a gas supply source 1 into a target chamber 3 via a buffer chamber 2. The system includes a first solenoid valve 10, a second solenoid valve 20, and a control module 30. The gas supply source 1 provides the gas to be introduced, the buffer chamber 2 is an intermediate buffer container located between the gas supply source 1 and the target chamber 3, and the target chamber 3 is the working chamber into which the gas is finally introduced. This system is particularly suitable for the precise introduction control of internal standard saturated vapor in mass spectrometry analysis equipment.

[0025] The first solenoid valve 10 is connected between the gas supply source 1 and the buffer chamber 2, and is used to control the on / off flow of gas from the gas supply source 1 into the buffer chamber 2. The second solenoid valve 20 is connected between the buffer chamber 2 and the target chamber 3, and is used to control the on / off flow of gas from the buffer chamber 2 into the target chamber 3. Both the first solenoid valve 10 and the second solenoid valve 20 can be two-position, two-way, direct-acting miniature solenoid valves. The valve body material is selected according to the chemical properties of the gas being introduced. For example, a PTFE seal is installed inside the stainless steel valve body to meet the requirements of corrosion resistance and sealing. The response time is preferably in the millisecond range to meet the needs of high-frequency on / off control.

[0026] The control module 30 is electrically connected to the first solenoid valve 10 and the second solenoid valve 20 respectively, and is used to output corresponding drive signals to control the first solenoid valve 10 and the second solenoid valve 20 to perform on / off actions according to a set timing sequence. The control module 30 can be a digital control circuit based on an ARM Cortex-M series microcontroller, such as GD32F303CBT6 or STM32F103C8T6.

[0027] In some preferred embodiments, the control module 30 includes a timing control unit 31 and a PWM generation unit 32. Specifically, a first drive signal is generated and output by the timing control unit 31 to control the opening and closing of the first solenoid valve 10; a second drive signal is generated and output by the PWM generation unit 32 according to a preset frequency and a preset duty cycle to control the high-frequency on / off operation of the second solenoid valve 20. It is understood that the timing control unit 31 and the PWM generation unit 32 can be two independent functional modules within the same microcontroller chip, or two independent microcontroller chips, or implemented using other programmable logic devices such as FPGAs.

[0028] The working process of this embodiment is as follows: In response to an externally input trigger signal, the control module 30 first outputs a first drive signal to open the first solenoid valve 10, allowing the gas supply source 1 to fill the buffer chamber 2 with gas. When the preset filling condition is met, the control module 30 controls the first solenoid valve 10 to close, isolating the buffer chamber 2 from the gas supply source 1. Subsequently, after confirming that the first solenoid valve 10 is in the closed state, the control module 30 generates a second drive signal. The second drive signal drives the second solenoid valve 20 to perform high-frequency on / off operations at a preset frequency and preset duty cycle, releasing the gas in the buffer chamber 2 into the target chamber 3 in batches.

[0029] Through the aforementioned timing control, this embodiment first pre-charges the buffer chamber 2 with gas from the gas supply source 1. Once charging is complete, the buffer chamber 2 is immediately isolated from the gas supply source 1. Then, the gas already charged in the buffer chamber 2 is released in batches in small quantities through the high-frequency switching of the second solenoid valve 20. Due to the presence of the buffer chamber 2, the gas supply source 1 and the target chamber 3 are never directly connected during the gas release process. The target chamber 3 only receives a limited amount of gas from the buffer chamber 2, avoiding a concentrated influx of gas caused by continuous gas supply pressure. Consequently, the environmental stability of the target chamber 3 is significantly improved.

[0030] Regarding the preset charging conditions, in this embodiment, the preset charging condition is a preset duration. Specifically, the control module 30 starts timing from the moment the first solenoid valve 10 opens. When the timing reaches the preset duration, it determines that the preset charging condition is met, and then controls the first solenoid valve 10 to close. The preset duration can be calibrated and set according to the volume of the buffer chamber 2, the gas pressure of the gas supply source 1, and the target charging amount. For example, it can be set to any value between 500ms and 3000ms.

[0031] Understandably, as an alternative, the preset filling condition can also be that the gas pressure in the buffer chamber 2 reaches a preset pressure threshold. In this case, a pressure sensor needs to be installed in the buffer chamber 2, and the control module 30 determines whether the preset pressure threshold has been reached based on the detection signal of the pressure sensor.

[0032] Regarding the PWM control parameters of the second drive signal, the specific values ​​of the preset frequency and preset duty cycle are set according to the gas introduction rate requirements of the target cavity 3. For example, the preset frequency can be set to any value between 10Hz and 1000Hz, and the preset duty cycle can be set to any value between 1% and 50%. High-frequency switching causes the second solenoid valve 20 to open only a tiny time window in each switching cycle, releasing the gas in the buffer cavity 2 sequentially in the form of micro-pulses. Compared to continuous opening, this high-frequency pulsed release method can prevent a large influx of gas into the target cavity in a short period, thereby effectively suppressing the fluctuation amplitude of the target cavity environment.

[0033] Understandably, the preset frequency and preset duty cycle can be adjusted according to the actual application scenario, and different application scenarios can correspond to different parameter configuration combinations.

[0034] Regarding the isolation drive structure between the control module and the first solenoid valve, such as Figure 2 As shown, it illustrates the circuit diagram of the first isolation drive circuit and the first solenoid valve in this embodiment.

[0035] In this circuit, the PB7 pin of the control module 30 serves as the output terminal of the first drive signal, and is connected to the anode of the LED on the primary side of the first optocoupler U1 via resistor R2. The cathode of the LED is grounded. The first optocoupler U1 is preferably a PC817C type optocoupler. When the PB7 pin outputs a high-level first drive signal, resistor R2 limits the drive current, and the LED on the primary side of the optocoupler conducts and emits light; when the PB7 pin outputs a low level, the LED is turned off.

[0036] The secondary side of the first optocoupler U1 is powered by +3.3V, and its output is connected to the base of the first switching transistor Q1 via resistor R20. The emitter of the first switching transistor Q1 is grounded. The first switching transistor Q1 is preferably an S8050 NPN transistor. When the first optocoupler U1 is turned on, its output is pulled high, providing a drive voltage to the base of the first switching transistor Q1 via resistor R20, thus turning on Q1. When the first optocoupler U1 is turned off, there is no drive voltage to the base of the first switching transistor Q1, thus turning it off. Furthermore, resistor R19 is connected between the base of the first switching transistor Q1 and ground to reliably pull the base down to a low level when the optocoupler is turned off, preventing the first switching transistor Q1 from being mistakenly turned on.

[0037] The collector of the first switching transistor Q1 is connected to one end of the coil of the first relay K1, and the other end of the coil of the first relay K1 is connected to a +3.3V power supply. The first relay K1 is preferably an HRS4H-S-DC3V-C type relay. The normally open contact of the first relay K1 is connected in series in the power supply circuit of the first solenoid valve 10, which is powered by a +24V power supply through a current-limiting resistor R1. One end of the first solenoid valve 10 is connected to +24V via resistor R1, and the other end is connected to the normally open contact of the first relay K1.

[0038] The working process is as follows: When the control module 30 needs to open the first solenoid valve 10, the PB7 pin outputs a high level, the first optocoupler U1 is turned on, driving the first switching transistor Q1 to turn on, the coil of the first relay K1 is energized, its normally open contact is closed, the power supply circuit of the first solenoid valve 10 is connected, and the first solenoid valve 10 starts working. When the control module 30 needs to close the first solenoid valve 10, the PB7 pin outputs a low level, the first optocoupler U1 is turned off, the first switching transistor Q1 is turned off, the coil of the first relay K1 is de-energized, its normally open contact is opened, the power supply circuit of the first solenoid valve 10 is disconnected, and the first solenoid valve 10 stops working.

[0039] Regarding circuit protection, this circuit incorporates dual freewheeling protection at critical nodes. Specifically, a first freewheeling diode D3 is connected in reverse parallel across the coil of the first relay K1. Its cathode is connected to a +3.3V power supply, and its anode is connected to the collector of the first switching transistor Q1. The first freewheeling diode D3 is preferably an SS34 Schottky diode. When the first switching transistor Q1 switches from on to off, the coil of the first relay K1 generates a reverse induced electromotive force. The first freewheeling diode D3 provides a discharge path, circulating the energy of this reverse induced electromotive force between the diode and the coil. The voltage across the coil is clamped within the forward voltage drop range of the first freewheeling diode D3, thereby protecting the first switching transistor Q1 from high-voltage breakdown.

[0040] Furthermore, a second freewheeling diode D4 is connected in reverse parallel across the coil of the first solenoid valve 10, with its cathode connected to +24V and its anode connected to the normally open contact of the first relay K1. The second freewheeling diode D4 is preferably an SS34 type Schottky diode. When the contact of the first relay K1 switches from closed to open, the coil of the first solenoid valve 10 will also generate a reverse induced electromotive force. The second freewheeling diode D4 provides a nearby discharge circuit for the coil of the first solenoid valve 10, absorbing this reverse induced electromotive force and preventing high-voltage pulses from causing electrolytic corrosion or breakdown damage to the contacts and front-end circuit of the first relay K1.

[0041] The first optocoupler U1 provides electrical isolation between the digital control circuit (+3.3V logic side) of the front-end control module 30 and the back-end power circuit (+24V solenoid valve drive side). During the on / off process of the solenoid valve, the surge current and electromagnetic interference generated by the back-end power circuit cannot be conducted to the PB7 pin of the control module 30 through the electrical path, thus ensuring the stable operation of the control module 30. Through the above circuit design, the first solenoid valve drive circuit integrates a triple protection mechanism of optocoupler isolation, relay drive, and freewheeling current absorption.

[0042] Regarding the isolation drive structure between the control module and the second solenoid valve, such as Figure 3 As shown, it illustrates the circuit diagram of the second isolation drive circuit and the second solenoid valve in this embodiment.

[0043] Unlike the first solenoid valve 10, which uses a three-stage drive structure of optocoupler + transistor + relay, the drive circuit of the second solenoid valve 20 uses a direct optocoupler drive structure. Specifically, the PB6 pin of the control module 30 serves as the output terminal of the second drive signal (PWM pulse width modulation signal), which is connected to the anode of the LED on the primary side of the second optocoupler J2 via resistor R17, and the cathode of the LED is grounded. The second optocoupler J2 preferably uses a TLP127 type optocoupler, which integrates a photodiode and a Darlington output transistor, and can output a current of over 150mA, enabling it to directly drive small solenoid valves.

[0044] When the PWM signal output from pin PB6 is high, resistor R17 limits the drive current, the LED on the primary side of the second optocoupler J2 illuminates, and the Darlington output transistor on the secondary side conducts accordingly, connecting the power supply circuit of the second solenoid valve 20. When the PWM signal is low, the LED on the primary side of the second optocoupler J2 turns off, the output transistor on the secondary side turns off, and the power supply circuit of the second solenoid valve 20 is disconnected. Since the PWM signal output from pin PB6 is a high-frequency square wave signal (e.g., 10Hz to 1000Hz), the second solenoid valve 20 performs high-frequency switching actions at the same frequency, realizing the batch-by-batch, minute release of gas from buffer chamber 2 into target chamber 3.

[0045] The power supply circuit for the second solenoid valve 20 is powered by a +24V power supply through a current-limiting resistor R12. One end of the second solenoid valve 20 is connected to the +24V power supply via resistor R12, and the other end is connected to the collector of the secondary output transistor of the second optocoupler J2. The emitter of the secondary output transistor of the second optocoupler J2 is grounded. When the second optocoupler J2 is turned on, the power supply circuit for the second solenoid valve 20 forms a complete current path through the internal output transistor of the optocoupler, and the second solenoid valve 20 starts to work.

[0046] Regarding freewheeling protection, since the second solenoid valve 20 is also an inductive load, a reverse induced electromotive force (EMF) will be generated at the moment of its de-energization. The amplitude of this EMF may far exceed +24V, posing a breakdown threat to the output transistor inside the second optocoupler J2. Therefore, a freewheeling diode D2 is connected in reverse parallel across the coil of the second solenoid valve 20, with its cathode connected to +24V and its anode connected to the output terminal of the second optocoupler J2. The freewheeling diode D2 is preferably an SS34 Schottky diode. At the moment the second optocoupler J2 switches from on to off, the reverse induced EMF generated by the coil of the second solenoid valve 20 forms a discharge circuit in the freewheeling diode D2. The voltage across the coil is clamped within the forward voltage drop range of the freewheeling diode D2, thereby protecting the output transistor inside the second optocoupler J2 from high-voltage breakdown.

[0047] Regarding electrical isolation, the second optocoupler J2 provides electrical isolation between the digital control circuit of the front-end control module 30 and the power circuit of the back-end second solenoid valve 20. Since the second solenoid valve 20 operates in a high-frequency PWM mode, frequent current surges occur in its power supply circuit, generating corresponding electromagnetic interference. Through the isolation provided by the second optocoupler J2, surges and electromagnetic interference from the back-end power circuit cannot be conducted to the PB6 pin of the control module 30, avoiding the impact of high-frequency switching noise on the normal operation of the control module 30. Simultaneously, since the second solenoid valve 20 does not require a relay for driving, the problems of insufficient contact life and response delay of mechanical relays under high-frequency operating conditions are avoided, which is beneficial to improving the response accuracy and long-term reliability of PWM control. The direct driving method of the second optocoupler J2, combined with the reverse parallel protection of the freewheeling diode D2, achieves effective protection of the control module 30 and reliable driving of the solenoid valve while simplifying the structure.

[0048] This embodiment also includes a communication module 60 and an isolated power supply module 70. The communication module 60 is electrically connected to the control module 30 and is used to receive trigger signals sent by an external host computer and transmit the trigger signals to the control module 30.

[0049] In one specific implementation, the communication module 60 is an RS-485 communication module, including a TTL to 485 level conversion chip, which can convert the TTL level signal of the control module 30 into a 485 differential signal for transmission, and at the same time convert the received 485 differential signal into a TTL level signal for transmission to the control module 30.

[0050] The isolated power supply module 70 uses an isolated DC-DC power module U2 to convert the externally input +24V power supply into an isolated +3.3V power supply, providing operating voltage for both the control module 30 and the communication module 60. The isolated DC-DC power module U2 is preferably an IB2403S_2WR3 type power module.

[0051] Specifically, an external +24V DC power supply is connected to the input terminal of the isolated power supply module 70 via connector J5. After being filtered by the input-side filter capacitor E1, it is input to the VIN and GND pins of the IB2403S_2WR3 power supply module. This power supply module internally incorporates a high-frequency isolation transformer and feedback control circuit, which converts the +24V input voltage into a stable +3.3V output voltage and achieves electrical isolation between the input and output terminals. The converted +3.3V voltage is then filtered by the output-side filter capacitor E2 and output from the module's output terminal, connecting to the power supply ports of the control module 30 and the communication module 60, respectively. The capacitance and withstand voltage values ​​of E1 and E2 can be adjusted according to the actual power supply ripple characteristics; for example, electrolytic or ceramic capacitors with capacitance values ​​from 10μF to 100μF and withstand voltage values ​​from 16V to 25V can be selected.

[0052] The input-side filter capacitor E1 is used to filter out ripple and noise introduced by the external power supply, and to prevent high-frequency interference from entering the power module and affecting the conversion efficiency; the output-side filter capacitor E2 is used to smooth the switching ripple generated during the DC-DC conversion process, and to ensure that the +3.3V power supply output to the control module 30 and the communication module 60 is stable and clean.

[0053] The core function of the IB2403S_2WR3 power module lies in its isolation characteristics. Internally, the module uses an isolation transformer to physically isolate the input +24V power supply circuit from the output +3.3V power supply circuit, with an isolation withstand voltage typically exceeding 1500VDC. Fluctuations, surges, and common-mode interference from the external power supply cannot couple to the output side through the transformer, thus avoiding the impact of grid noise and ground loop interference on the normal operation of the control module 30.

[0054] By combining the signal isolation of the isolated power supply module 70 with that of the first optocoupler U1 and the second optocoupler J2, this embodiment achieves complete electrical isolation between the control module 30 and the back-end power circuit in both power supply and signal dimensions. In terms of power supply, the isolated power supply module 70 isolates the power supply of the control module 30 from the external +24V power supply. In terms of signal, the first optocoupler U1 and the second optocoupler J2 isolate the drive signal output terminal of the control module 30 from the back-end solenoid valve power circuit. This dual isolation mechanism works synergistically, preventing interference from either the power supply or signal transmission end from reaching the control module 30, effectively improving the electromagnetic compatibility and anti-interference capability of the control system.

[0055] In summary, the dual-valve timing isolation control system provided in this embodiment, through the timing coordination of the first solenoid valve 10, the buffer chamber 2, and the second solenoid valve 20, as well as the PWM high-frequency on / off control of the second solenoid valve 20, achieves the batch, minute, and stable introduction of gas from the gas supply source 1 to the target chamber 3. Compared with the existing technology that uses a single valve for direct on / off, this embodiment avoids the drastic environmental fluctuations caused by a sudden large influx of gas into the target chamber 3. Compared with the existing solution that uses simple series connection of two valves, this embodiment, through the timing logic of pre-charging, then isolation, and finally pulse release, ensures that the pressure of the gas supply source 1 is effectively isolated by the buffer chamber 2 during the release phase. The release process relies solely on the natural diffusion of a fixed amount of gas within the buffer chamber 2, truly achieving independent controllability of the injection volume and injection rate. At the hardware circuit level, this embodiment effectively improves the anti-interference capability and long-term operational reliability of the control circuit through the combination of optocoupler isolation and freewheeling diode protection.

[0056] Second Embodiment The second embodiment of the present invention provides a dual-valve timing isolation control method, which is applied to the dual-valve timing isolation control system in the first embodiment described above.

[0057] Figure 4 A flowchart illustrating the steps of the dual-valve timing isolation control method provided in the second embodiment of the present invention is shown. As shown in the figure, the method includes steps S101-S105.

[0058] Step S101: After the control module 30 is powered on, it controls the first solenoid valve 10 and the second solenoid valve 20 to remain in the closed state, so that the air supply source 1, the buffer chamber 2 and the target chamber 3 are isolated from each other.

[0059] Specifically, the isolation state during the initialization phase means that the gas in the gas supply source 1 cannot enter the buffer chamber 2 through the first solenoid valve 10, and the gas in the buffer chamber 2 cannot enter the target chamber 3 through the second solenoid valve 20. At this time, the target chamber 3 maintains its original working state, for example, the mass spectrometer chamber maintains a high vacuum working environment and is not disturbed by any gas introduction operation.

[0060] Step S102: In response to the externally input trigger signal, the control module 30 outputs a first drive signal to open the first solenoid valve 10, so that the gas supply source 1 fills the buffer chamber 2 with gas until the preset filling condition is reached.

[0061] Specifically, the external host computer sends an internal standard introduction command to the control module 30 via the communication module 60 as a trigger signal. After receiving the trigger signal, the control module 30 first outputs a first drive signal through the timing control unit 31. The first drive signal drives the first solenoid valve 10 to open via the first isolation drive circuit 40. The gas stored in the gas supply source 1 (e.g., internal standard saturated vapor) enters the buffer chamber 2 through the first solenoid valve 10 under its own pressure difference, and the amount of gas in the buffer chamber 2 gradually increases. During this process, the control module 30 continuously monitors the filling status until the preset filling condition is reached. As mentioned above, the preset filling condition can be a preset duration. The control module 30 starts timing from the moment the first solenoid valve 10 opens, and determines that filling is complete when the preset duration is reached. Those skilled in the art will understand that the preset duration should be pre-calibrated based on parameters such as the buffer chamber volume and the gas supply source pressure to ensure that the amount of gas filled in the buffer chamber meets the subsequent release requirements without causing excessive pressure in the buffer chamber due to overfilling.

[0062] Step S103: When the preset filling conditions are met, the control module 30 controls the first solenoid valve 10 to shut off, so that the buffer chamber 2 is isolated from the air supply source 1, and the buffer chamber 2 and the target chamber 3 are kept isolated.

[0063] Specifically, after charging is complete, the timing control unit 31 removes the first drive signal, the first switch 42 in the first isolation drive circuit 40 is turned off, the contacts of the first relay 43 are opened, and the first solenoid valve 10 is de-energized and closed. At this time, one end of the buffer chamber 2 (the end connected to the gas supply source 1) is closed by the first solenoid valve 10, and the other end (the end connected to the target chamber 3) is still closed by the second solenoid valve 20, which is in the off state. The buffer chamber 2 forms a closed intermediate container, which stores a fixed amount of gas, but is isolated from both the gas supply source 1 and the target chamber 3. This isolation means that the pressure of the gas supply source 1 will not continuously act on the buffer chamber 2, and the amount of gas in the buffer chamber 2 is determined before the second solenoid valve 20 is opened, and will not be affected by the pressure fluctuation of the gas supply source, thus ensuring the controllability of the subsequent release process.

[0064] Step S104: After confirming that the first solenoid valve 10 is in the closed state, the control module 30 generates a second drive signal. The second drive signal drives the second solenoid valve 20 to perform high-frequency on / off action at a preset frequency and preset duty cycle, so as to release the gas in the buffer chamber 2 to the target chamber 3 in batches.

[0065] Specifically, after the first solenoid valve 10 is turned off, the control module 30 generates a PWM pulse width modulation signal with a preset frequency and preset duty cycle through the PWM generation unit 32, which is output as the second drive signal. The second drive signal drives the second solenoid valve 20 through the second isolation drive circuit 50. Since the second drive signal is a high-frequency PWM signal, the second solenoid valve 20 performs on-off action at the same frequency. When the PWM signal is high, the second solenoid valve 20 opens, and the gas in the buffer chamber 2 releases a small amount of gas into the target chamber 3 through the second solenoid valve 20; when the PWM signal is low, the second solenoid valve 20 closes, and the release is paused. This high-frequency alternation divides the gas in the buffer chamber 2 into multiple small batches, which are released into the target chamber 3 one by one. Since the amount of gas released in each batch depends on the single opening duration of the second solenoid valve 20 (determined by the PWM duty cycle), the release rate can be precisely controlled by adjusting the duty cycle; and the high-frequency characteristics make the release process approximately a continuous and stable micro-injection, avoiding the step-like fluctuations in the target chamber pressure that may be caused by pulsed release. Compared to a single concentrated release, this batch release method allows the target cavity 3 to receive only a small amount of gas at any given time, resulting in gradual changes in the internal environmental parameters (such as vacuum level and pressure) of the target cavity 3.

[0066] Step S105: After the gas in the buffer chamber 2 is completely released, the control module 30 controls the second solenoid valve 20 to close, so that both the first solenoid valve 10 and the second solenoid valve 20 remain closed, and the gas supply source 1, the buffer chamber 2 and the target chamber 3 are isolated from each other.

[0067] Specifically, the control module 30 determines that the gas in the buffer chamber 2 has been completely released based on preset release conditions (such as reaching a preset number of PWM on / off cycles or a preset release duration), and then stops outputting the PWM signal, and the second solenoid valve 20 is closed. At this time, the system returns to the same three-terminal isolation state as the initialization state, completing a complete gas introduction control process, and waits for the next trigger signal.

[0068] Through the five steps described above, this invention achieves a complete control cycle of pre-charging, isolation, pulse release, and reset. The pre-charging and isolation steps ensure that the total amount of gas introduced into the target cavity each time is controllable, while the pulse release step achieves a minute-by-minute release of this total amount. These three steps are interconnected and indispensable, collectively guaranteeing the stability and controllability of the gas introduction process.

[0069] Regarding the specific method of adjusting the release rate using the PWM signal in step S104, in some embodiments, the second driving signal is a PWM pulse width modulation signal. By adjusting the preset duty cycle, the on-time of the second solenoid valve 20 in each on-off cycle is controlled to adjust the rate at which gas is released from the buffer chamber 2 to the target chamber 3. Specifically, when the preset duty cycle increases, the opening time of the second solenoid valve 20 in each cycle is prolonged, the amount of gas released in a single pulse cycle increases, and the total release rate per unit time increases; conversely, when the preset duty cycle decreases, the release rate decreases. The setting of the preset frequency determines the action response characteristics of the second solenoid valve 20. The higher the frequency, the smaller the amount of gas released in a single pulse, and the more uniform and continuous the release process becomes. In practical applications, the preset frequency is preferentially selected based on the response speed of the second solenoid valve 20. For example, the highest frequency value that the second solenoid valve 20 can reliably respond to is selected to achieve optimal release uniformity while ensuring reliable valve operation.

[0070] Regarding the specific implementation of the preset charging condition in step S102, in some embodiments, the preset charging condition is a preset duration. Specifically, the control module 30 starts timing from the moment the first solenoid valve 10 opens, and controls the first solenoid valve 10 to close when the preset duration is reached. The specific value of this preset duration depends on the volume of the buffer chamber 2 and the gas pressure of the gas supply source 1. For example, under the conditions that the buffer chamber volume is 5mL and the gas supply pressure is 1.5 times atmospheric pressure, the preset duration can be set to 1000ms. Within this duration, the amount of gas charged into the buffer chamber 2 by the gas supply source 1 is sufficient to meet the requirements of a complete release, while the pressure in the buffer chamber 2 will not exceed the safety threshold. It is understood that the preset duration can be calibrated and adjusted according to actual working conditions.

[0071] Third Embodiment A third embodiment of the present invention provides a mass spectrometry internal standard introduction device. The device includes a gas supply source 1, a buffer chamber 2, a target chamber 3, and a dual-valve timing isolation control system as described in the first embodiment. The gas supply source 1 is an internal standard liquid storage container for providing saturated vapor, the target chamber 3 is a mass spectrometry analysis chamber, and the buffer chamber 2 is an isolation buffer chamber disposed between the internal standard liquid storage container and the mass spectrometry analysis chamber. By applying this device to a mass spectrometry analysis device, a stable and controllable introduction of saturated vapor can be achieved, ensuring the stability of the high vacuum environment of the mass spectrometry chamber while performing internal standard calibration, thus helping to improve the accuracy of quantitative mass spectrometry analysis.

[0072] In some embodiments, the freewheeling diodes D2 and D4 are Schottky diodes of type 1N5819, with a forward voltage drop of about 0.45V and a reverse recovery time of about 10ns, which can quickly respond to the reverse induced electromotive force at the moment the coil is de-energized.

[0073] Understandably, as an alternative, Schottky diodes such as SS34 and BAT54 can also be used, as long as their reverse withstand voltage and forward current capability are not lower than the induced energy generated by the solenoid valve coil at the moment of power failure. The above alternatives can also achieve the function of discharging the reverse induced electromotive force, and all fall within the protection scope of the claims of this invention.

[0074] In some embodiments, the first solenoid valve 10 and the second solenoid valve 20 are both two-position two-way direct-acting solenoid valves, which have the characteristics of simple structure, fast response speed and high reliability.

[0075] Understandably, as an alternative, the first solenoid valve 10 can also be a pilot-operated solenoid valve. Since the first solenoid valve 10 only performs a single opening and closing operation (non-high-frequency action), the pilot-operated solenoid valve can also meet the functional requirements.

[0076] In summary, the dual-valve time-sequential isolation control system and its control method provided by this invention, through the sequential coordination of the first solenoid valve, the buffer chamber, and the second solenoid valve, and the PWM high-frequency on / off control of the second solenoid valve, achieves the batch, minute, and stable introduction of gas from the gas supply source to the target cavity. Compared with the existing technology that uses a single valve for direct on / off, this invention avoids the drastic environmental fluctuations caused by a sudden surge of large amounts of gas into the target cavity. Compared with the existing scheme that uses simple series connection of two valves, this invention, through the timing logic of pre-charging, then isolation, and finally pulse release, effectively isolates the gas supply source pressure by the buffer chamber during the release phase. The release process relies solely on the natural diffusion of a quantitative amount of gas within the buffer chamber, truly achieving independent controllability of the injection volume and injection rate. Furthermore, it eliminates the need for additional pressure sensors or flow meters within the target cavity, reducing system complexity and cost. At the hardware circuit level, this invention, through the combination of optocoupler isolation and freewheeling diode protection, effectively improves the anti-interference capability and long-term operational reliability of the control circuit, making it particularly suitable for mass spectrometry analysis equipment with high requirements for electromagnetic compatibility and stability.

[0077] The above description is merely a preferred embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features disclosed in this disclosure that have similar functions.

[0078] Furthermore, while the operations are described in a specific order, this should not be construed as requiring these operations to be performed in the specific order shown or in a sequential order. In certain environments, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of this disclosure. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0079] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A dual-valve time-sequential isolation control system for introducing gas from a gas supply source into a target cavity via a buffer chamber, characterized in that, include: A first solenoid valve is connected between the air supply source and the buffer chamber; A second solenoid valve is connected between the buffer chamber and the target chamber; The control module is electrically connected to the first solenoid valve and the second solenoid valve respectively; The control module responds to an externally input trigger signal and outputs a first drive signal to open the first solenoid valve, so that the gas supply source fills the buffer chamber with gas; when the preset filling conditions are met, the control module controls the first solenoid valve to close, so that the buffer chamber is isolated from the gas supply source. After confirming that the first solenoid valve is in the closed state, the control module generates a second drive signal. The second drive signal is used to drive the second solenoid valve to perform high-frequency on / off action at a preset frequency and preset duty cycle, so as to release the gas in the buffer cavity into the target cavity in batches.

2. The dual-valve time-sequential isolation control system according to claim 1, characterized in that, The control module includes a timing control unit and a PWM generation unit; the first drive signal is generated and output by the timing control unit; the second drive signal is generated and output by the PWM generation unit according to a preset frequency and a preset duty cycle.

3. The dual-valve time-sequential isolation control system according to claim 1, characterized in that, The control module is electrically connected to the first solenoid valve through a first isolation drive circuit. The first isolation drive circuit includes a first optocoupler, a first switching transistor, and a first relay. The first drive signal is transmitted to the control terminal of the first switching transistor after being isolated by the first optocoupler. The first switching transistor controls the on / off state of the coil of the first relay. The contacts of the first relay are connected to the power supply circuit of the first solenoid valve.

4. The dual-valve time-sequential isolation control system according to claim 1, characterized in that, The control module is electrically connected to the second solenoid valve through a second isolation drive circuit, which includes a second optocoupler and a second switch. The second drive signal is transmitted to the control terminal of the second switch after being isolated by the second optocoupler. The second switch is connected in series in the power supply circuit of the second solenoid valve.

5. A dual-valve time-sequential isolation control system according to claim 3 or 4, characterized in that, Both the first and second solenoid valves have freewheeling diodes connected in reverse parallel across their coils to form a discharge circuit for the reverse induced electromotive force at the moment the coil is de-energized.

6. A dual-valve time-sequential isolation control system according to claim 1, characterized in that, It also includes a communication module and an isolated power supply module; the communication module is electrically connected to the control module and is used to receive the trigger signal sent by an external host computer and transmit the trigger signal to the control module; the input terminal of the isolated power supply module is connected to an external power supply, and its output terminal is connected to the power supply ports of the control module and the communication module respectively, so as to realize power supply isolation.

7. A dual-valve time-sequential isolation control method, applied to a dual-valve time-sequential isolation control system as described in any one of claims 1-6, characterized in that, Includes the following steps: After the control module is powered on, it controls both the first solenoid valve and the second solenoid valve to remain in the closed state, thereby isolating the air supply source, the buffer chamber and the target chamber from each other. The control module responds to an externally input trigger signal and outputs a first drive signal to open the first solenoid valve, so that the gas supply source fills the buffer chamber with gas until the preset filling condition is reached. When the preset filling condition is met, the control module controls the first solenoid valve to shut off, thereby isolating the buffer chamber from the air supply source and keeping the buffer chamber isolated from the target chamber. After confirming that the first solenoid valve is in the off state, the control module generates a second drive signal. The second drive signal drives the second solenoid valve to perform high-frequency on / off action at a preset frequency and preset duty cycle, so as to release the gas in the buffer cavity into the target cavity in batches. After the gas in the buffer chamber is completely released, the control module controls the second solenoid valve to close, so that both the first solenoid valve and the second solenoid valve remain closed, and the gas supply source, the buffer chamber and the target chamber are isolated from each other.

8. The dual-valve timing isolation control method according to claim 7, characterized in that, The second driving signal is a PWM pulse width modulation signal. By adjusting the size of the preset duty cycle, the on-time of the second solenoid valve in each on-off cycle is controlled to adjust the rate at which the gas in the buffer chamber is released into the target chamber.

9. The dual-valve timing isolation control method according to claim 7, characterized in that, The preset charging condition is a preset duration. The control module starts timing from the moment the first solenoid valve is opened, and controls the first solenoid valve to close when the preset duration is reached.

10. A mass spectrometry internal standard introduction device, characterized in that, It includes a gas supply source, a buffer chamber, a target chamber, and a dual-valve time-sequential isolation control system as described in any one of claims 1-6; the gas supply source is an internal standard liquid storage container for providing internal standard saturated vapor, the target chamber is a mass spectrometry analysis chamber, and the buffer chamber is an isolation buffer chamber disposed between the internal standard liquid storage container and the mass spectrometry analysis chamber.

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