A secondary vapor recovery system for gas stations with ORVR compatibility

Abstract

This invention discloses an ORVR-compatible secondary vapor recovery system for gas stations, comprising an underground oil tank, a PV valve on the discharge pipe, an ORVR vapor recovery refueling nozzle, a China VI B emission standard vehicle, an ORVR fuel tank, an oil pump, a flow measurement transducer, a vapor recovery vacuum pump, a control mainboard, a vapor recovery control mainboard, an indicator device, a gas path switch valve, a gas path bypass, a pressure sensor, a nozzle holder ring at the fuel tank opening, a vapor collection hood, and a nozzle head. The oil pump and flow measurement transducer are respectively connected to the underground oil tank and the ORVR vapor recovery refueling nozzle via pipelines, and the vapor recovery vacuum pump is connected to the ORVR vapor recovery refueling nozzle and the underground oil tank via pipelines. This invention relates to an ORVR-compatible secondary vapor recovery system for gas stations, featuring compatibility with both ORVR and non-ORVR vehicles, no backflushing of vapors when the pump is started, automatic mode switching, low-speed continuous operation of the vacuum pump to prevent wear, accurate and compliant gas-liquid ratio, efficient sealed recovery, and stable operation of the dual-plate system.

Description

Technical Field

[0001] This invention belongs to the technical field of secondary oil and gas recovery systems, specifically an ORVR-compatible secondary oil and gas recovery system for gas stations. Background Technology

[0002] The secondary oil and gas recovery system at gas stations is an environmentally friendly and safe device used in conjunction with gas stations. It mainly collects, transports, and treats the volatile oil and gas during the refueling process, effectively reducing the spread of oil and gas, lowering safety risks and environmental pollution, while improving energy utilization efficiency and meeting the safety and environmental management requirements of gas station operations.

[0003] Existing secondary vapor recovery systems at gas stations suffer from numerous technical defects: Traditional systems' vapor recovery vacuum pumps only activate upon receiving refueling pulse signals, resulting in start-up delays and a risk of vapors from underground tanks being backflushed into the vehicle's fuel tank or the atmosphere, causing pollution; ORVR vehicles meeting the China VI B emission standard have slightly negative pressure fuel tanks, making traditional systems prone to vacuum pump blockage and jamming, leading to severe equipment wear and short lifespan; existing systems cannot automatically distinguish between ORVR and non-ORVR vehicles, and the gas-liquid ratio cannot simultaneously meet the regulatory requirements for both types of vehicles, necessitating manual mode switching, which is cumbersome; some retrofit plans require modifications to existing gas pipelines, affecting the vapor recovery effect of traditional vehicles and failing to simultaneously comply with China VI regulations and local environmental standards; poor sealing between the refueling nozzle and the fuel tank opening allows vapors to escape easily, resulting in low recovery efficiency and poor environmental performance. Therefore, an ORVR-compatible secondary vapor recovery system for gas stations needs to be designed. Summary of the Invention The purpose of this invention is to solve the above-mentioned problems and provide a secondary oil and gas recovery system for gas stations based on gun lifting pre-rotation, speed determination, and low-speed non-stop pump control logic, which can automatically identify ORVR / non-ORVR vehicles and accurately meet the dual-mode gas-liquid ratio requirements without modifying the original gas pipeline.

[0004] An ORVR-compatible secondary vapor recovery system for gas stations includes an underground oil tank, a PV valve on the discharge pipe, an ORVR vapor recovery refueling nozzle, a China VI B emission standard vehicle, an ORVR fuel tank, an oil pump, a flow measurement transducer, a vapor recovery vacuum pump, a metering and control main board, a vapor recovery control main board, an indicator device, a gas path switch valve, a gas path bypass, a pressure sensor, a nozzle retaining ring at the fuel tank opening, a vapor collection hood, and a nozzle head. The oil pump and flow measurement transducer are connected to the underground oil tank and the ORVR vapor recovery refueling nozzle via pipelines. The vapor recovery vacuum pump is connected to the ORVR vapor recovery refueling nozzle and the underground oil tank via pipelines. The PV valve on the discharge pipe is installed on the top of the underground oil tank. The metering and control main board, the vapor recovery control main board, and the indicator device are installed inside the refueling machine. The metering and control main board is electrically connected to the oil pump, the flow measurement transducer, and the indicator device.

[0005] The oil and gas recovery control main board is electrically connected to the oil and gas recovery vacuum pump, the gas circuit switch valve, and the pressure sensing device, respectively. The ORVR oil and gas recovery refueling nozzle is equipped with a nozzle head, and a gas collection hood is fitted on the outside of the nozzle head. The end of the gas collection hood is equipped with a fuel tank opening nozzle retainer. The refueling nozzle integrates a pressure sensing device, a gas circuit switch valve, and a gas circuit bypass. The China VI B vehicle is equipped with an ORVR fuel tank. When refueling, the ORVR oil and gas recovery refueling nozzle is inserted into the fuel tank opening. The fuel tank opening nozzle retainer fits and seals with the fuel tank opening to form a closed recovery chamber.

[0006] The oil and gas recovery control mainboard automatically switches between ORVR compatible mode and traditional non-ORVR mode based on the nozzle lifting signal, the status of the oil circuit solenoid valve, the refueling pulse signal, the pressure sensing device detection signal, and the vacuum pump speed feedback, so as to achieve precise adaptation of oil and gas recovery for different vehicles.

[0007] The ORVR oil and gas recovery refueling nozzle is fitted with a gas collection cover on the outside of the nozzle head, and a nozzle retainer ring is fixed to the end of the oil tank opening. During refueling, it fits tightly with the ORVR oil tank opening to prevent oil and gas from escaping and improve recovery efficiency.

[0008] The ORVR vapor recovery refueling nozzle is equipped with a pressure sensor that is electrically connected to the vapor recovery control main board. It monitors the fuel tank pressure in real time, providing a signal basis for vehicle type identification and mode switching.

[0009] The ORVR vapor recovery refueling nozzle is equipped with an internal gas circuit switch valve and a gas circuit bypass. The gas circuit switch valve can control the switching of the gas circuit between the main channel and the bypass channel, and the gas circuit bypass is used to adjust the return gas volume so that the gas-liquid ratio is stabilized in the range of 0.00–0.50 in ORVR mode.

[0010] The startup logic of the oil and gas recovery vacuum pump has been optimized: after the oil circuit solenoid valve is opened by lifting the nozzle, it immediately enters the low-speed pre-rotation mode instead of waiting for the refueling pulse signal to start, thus eliminating the startup delay and completely solving the problem of oil and gas backflush caused by excessive tank pressure.

[0011] ORVR mode control logic: If the oil and gas recovery control motherboard detects that the vacuum pump cannot reach the preset speed within 5 seconds, it is determined that the air path is blocked (ORVR vehicle). The system forces the system to enter the ORVR compatible mode, controls the vacuum pump to run continuously at low speed without stopping, and avoids equipment wear caused by stalling, jamming, and crawling.

[0012] Non-ORVR mode control logic: When the pressure sensor detects positive pressure in the fuel tank and the vacuum pump speed is normal and can reach the preset value, the system determines that it is a conventional vehicle, the main air passage is fully open, and the oil and gas recovery control motherboard adjusts the vacuum pump speed according to the refueling pulse signal using a PID algorithm to keep the gas-liquid ratio stable in the range of 1.00–1.20.

[0013] The control motherboard and the oil and gas recovery control motherboard are linked by signals to synchronously control the start, stop and operation status of the oil pump and the oil and gas recovery vacuum pump, ensuring that the oil circuit and the gas circuit operate in unison and improving system stability.

[0014] The PV valve on the discharge pipe is installed on the top of the underground oil tank to regulate the pressure inside the tank, prevent oil and gas from being directly discharged into the atmosphere, balance the system pressure, and improve environmental protection and safety performance.

[0015] This system requires no modification to the existing gas pipeline. It can be compatible with existing fuel dispensers simply by upgrading the program and replacing the ORVR fuel nozzle. The modification is convenient and low-cost, and does not affect the original recovery effect or equipment warranty in non-ORVR mode.

[0016] The beneficial effects of this invention are as follows: This invention relates to an ORVR-compatible secondary vapor recovery system for gas stations, which features compatibility with both ORVR and non-ORVR vehicles, no backflushing of vapors when the pump is started, automatic mode switching, continuous low-speed operation of the vacuum pump to prevent wear, accurate and compliant gas-liquid ratio, efficient sealed recovery, and stable operation of the dual-plate system. In practical use, compared with traditional ORVR-compatible secondary vapor recovery systems for gas stations, this ORVR-compatible secondary vapor recovery system has the following beneficial effects: First, by adopting the control logic of starting the vacuum pump immediately upon lifting the nozzle and continuously pumping at low speed in ORVR mode, the problems of vacuum pump start-up delay, oil and gas backflush, stalling and wear are completely solved, greatly extending the service life of the vacuum pump. Moreover, it can be compatible with existing fuel dispenser equipment without modifying the original air circuit structure, making the modification convenient and cost-effective. Secondly, the pressure sensing device automatically identifies ORVR and non-ORVR vehicles, accurately matching the corresponding gas-liquid ratio range, while meeting the National VI emission standards and local environmental protection standards; the gas collection cover at the end of the fuel nozzle and the nozzle retaining ring at the fuel tank opening form a sealing structure, effectively preventing oil and gas escape, improving oil and gas recovery efficiency and emission compliance, and reducing the environmental operation risks of gas stations. Attached Figure Description For ease of explanation, the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 For the present invention Figure 1 A schematic diagram of the ORVR (Organic Refrigerant Regulator) fuel nozzle structure.

[0018] In the diagram: 1. Underground oil tank; 2. PV valve for discharge pipe; 3. ORVR fuel refueling nozzle; 4. China VI B vehicle; 5. ORVR fuel tank; 6. Oil pump; 7. Flow measurement converter; 8. Fuel recovery vacuum pump; 9. Control board; 10. Fuel recovery control board; 11. Indicating device; 12. Gas circuit switch valve; 13. Gas circuit bypass; 14. Pressure sensing device; 15. Fuel tank opening nozzle retainer ring; 16. Gas collection hood; 17. Nozzle head. Detailed Implementation like Figure 1-2 As shown, the specific implementation adopts the following technical solution: An ORVR-compatible secondary vapor recovery system for gas stations includes an underground oil tank 1, a discharge pipe PV valve 2, an ORVR vapor recovery refueling nozzle 3, a China VI B emission standard vehicle 4, an ORVR fuel tank 5, an oil pump 6, a flow measurement transducer 7, a vapor recovery vacuum pump 8, a metering and control mainboard 9, a vapor recovery control mainboard 10, an indicator device 11, a gas path switch valve 12, a gas path bypass 13, a pressure sensing device 14, a nozzle retaining ring at the fuel tank opening 15, a vapor collection hood 16, and a nozzle head 17. The oil pump 6 and the flow measurement transducer 7 are... The underground oil tank 1 is connected to the ORVR vapor recovery refueling nozzle 3 via a pipeline. The vapor recovery vacuum pump 8 is connected to the ORVR vapor recovery refueling nozzle 3 and the underground oil tank 1 via a pipeline. The discharge pipe PV valve 2 is installed on the top of the underground oil tank 1. The discharge pipe PV valve 2 is installed on the top of the underground oil tank 1. It can adjust the pressure inside the tank and prevent the oil and gas inside the tank from being directly discharged into the atmosphere. This structure can balance the pressure inside the underground oil tank 1 and avoid excessive unorganized emission of oil and gas, further improving the environmental performance and operational safety of the gas station.

[0019] The main control board 9, the oil and gas recovery control board 10, and the indicator device 11 are installed inside the fuel dispenser. The main control board 9 and the oil and gas recovery control board 10 are linked by signals to synchronously control the start-up, shutdown, and operating status of the oil pump 6 and the oil and gas recovery vacuum pump 8. The dual-board collaborative control can ensure the consistency of the oil and gas circuits, optimize the system response speed, improve the operational stability of the entire recovery system, and reduce the risk of malfunction. The main control board 9 is electrically connected to the oil pump 6, the flow measurement converter 7, and the indicator device 11, respectively. The oil and gas recovery control board 10 is electrically connected to the oil and gas recovery vacuum pump 8, the gas circuit switch valve 12, and the pressure sensing device 14, respectively. The oil and gas recovery vacuum pump 8 is triggered by the nozzle lifting signal, rather than waiting for the refueling pulse signal to start. This setting eliminates the start-up delay of the oil and gas recovery system and completely solves the problem of oil and gas backflush when the pressure of the underground oil tank 1 is higher than the oil tank pressure, ensuring that oil and gas recovery and refueling are carried out synchronously.

[0020] The ORVR vapor recovery refueling nozzle 3 is equipped with a nozzle head 17, and a gas collection hood 16 is fitted around the nozzle head 17. A fuel tank opening nozzle retainer 15 is fixed to the end of the gas collection hood 16. This structure allows it to fit tightly against the fuel tank opening of the ORVR fuel tank 5 during refueling, forming a closed vapor recovery chamber to prevent vapor from escaping from the fuel tank opening and improve vapor recovery efficiency. The refueling nozzle contains a pressure sensor 14, a gas circuit switch valve 12, and a gas circuit bypass 13. The pressure sensor 14 is electrically connected to the vapor recovery control main board 10. The pressure sensor 14 can detect the pressure status inside the ORVR fuel tank 5 in real time, providing a signal basis for the system to automatically identify the vehicle type and switch the recovery mode, ensuring the accuracy of mode switching.

[0021] The ORVR vapor recovery refueling nozzle 3 is equipped with an air circuit switch valve 12 and an air circuit bypass 13. The air circuit switch valve 12 can control the air circuit to switch between the main channel and the air circuit bypass 13. The air circuit bypass 13 can adjust the return air volume of vapor recovery, so that the gas-liquid ratio in ORVR mode is controlled within the range of 0.00-0.50, which accurately matches the vapor recovery regulations of the China VI B vehicle 4. The China VI B vehicle 4 is equipped with an ORVR fuel tank 5. When refueling, the ORVR vapor recovery refueling nozzle 3 is inserted into the fuel tank opening of the ORVR fuel tank 5. The nozzle retaining ring 15 at the fuel tank opening is sealed to the fuel tank opening. The vapor recovery control main board 10 automatically switches between ORVR compatible mode and traditional mode according to the nozzle lifting signal, refueling pulse signal and the detection signal of the pressure sensing device 14 to realize vapor recovery for different vehicles.

[0022] The usage state of this invention is as follows: System workflow: Gun lifting trigger: Lifting the ORVR vapor recovery refueling gun 3 opens the fuel dispenser's oil circuit solenoid valve, the oil pump 6 prepares, and the vapor recovery control main board 10 immediately starts the vapor recovery vacuum pump 8 to enter low-speed pre-rotation. Nozzle sealing: Insert the fuel nozzle into the vehicle's fuel tank opening, and the fuel tank opening nozzle retaining ring 15 and the vent shroud 16 form a sealed fuel vapor recovery chamber. Pattern determination: ORVR vehicle (China VI B): The pressure sensor 14 detects a slight negative pressure and the vacuum pump cannot reach the preset speed within 5 seconds. The system determines that it is in ORVR mode, the gas circuit switch valve 12 switches to the gas circuit bypass 13, the vacuum pump maintains low speed and does not stop pumping, and the gas-liquid ratio is controlled at 0.00–0.50. For non-ORVR vehicles: Pressure sensor 14 detects positive pressure in the fuel tank, the vacuum pump speed is normal, the system is determined to be in traditional mode, the main air passage is fully open, the oil and gas recovery control main board 10 uses PID algorithm to adjust the speed according to the refueling pulse, and the gas-liquid ratio is stable at 1.00–1.20. Refueling metering: The main control board 9 controls the oil pump 6 to draw oil from the underground oil tank 1, the flow measurement converter 7 measures the flow in real time, and the indicator device 11 displays the refueling data and recovery status synchronously. Pressure balance: PV valve 2 on the top discharge pipe of underground oil tank 1 continuously regulates the pressure inside the tank to prevent unorganized emission of oil and gas; End of shutdown: Refueling completed, oil circuit solenoid valve closed, oil vapor recovery control main board 10 shuts down vacuum pump 8, completing one operation.

[0023] Operating principle in non-ORVR compatible mode: When the ORVR vapor recovery fuel nozzle 3 is inserted into the vehicle's fuel tank opening, the gas collection shroud 16 first seals the fuel tank opening. At this time, the gas pressure in the vehicle's fuel tank is the same as the pressure chamber of the pressure sensing module of the ORVR vapor recovery fuel nozzle 3.

[0024] For China VI B vehicles, because the car has a built-in oil vapor recovery system, the car's fuel tank is always in a slightly negative pressure state. When the pressure sensing diaphragm of the pressure sensing device 14 senses that the pressure of the ORVR fuel tank 5 is slightly negative, it will seal the main channel of oil vapor recovery under the action of atmospheric pressure. At this time, when the fuel gun is turned on to refuel, the vacuum pump can only recover a small amount of oil vapor from the bypass channel, and the gas-liquid ratio is ≤0.5. During a pilot test of onboard vapor recovery (ORVR) fuel dispenser, it was found that in ORVR compatible mode, after the fuel nozzle pressure sensing module detected the China VI B fuel tank, the fuel nozzle switched to ORVR compatible mode, and the return gas passage switched to a bypass passage. However, due to the high vacuum degree of the liquid seal in the ORVR fuel tank's guide pipe, the vacuum pump repeatedly started and stalled during operation, failing to reach the predetermined flow rate of the original control program. This resulted in a so-called overwork state with jamming or creeping, causing wear on the vacuum pump, sometimes requiring replacement every three months, severely impacting its lifespan and challenging the normal operation warranty period of the original non-ORVR mode pump. To improve this situation, one suggestion was to install a bypass overflow valve at the inlet and outlet of the variable frequency pump, but this solution requires modifying the original fuel dispenser's return gas passage, causing pressure loss and affecting the original non-ORVR mode's return gas volume, making it unacceptable. Another solution, to protect the vacuum pump from abnormal wear in ORVR mode, is to simply put the variable frequency vacuum pump into a stop state after the fuel nozzle pressure sensing valve detects the China VI B fuel tank. However, after stopping the pump, it was discovered that when the underground oil tank pressure was high, the oil vapor in the tank would flow through the underground gas pipeline, then through the oil gun gas line (the return gas valve is open during oil gun refueling), and backflow into the atmosphere through the oil gun nozzle hood. This could be observed using an oil vapor infrared imaging tester, so this solution also failed. Furthermore, it was found that during the initial gas-liquid ratio test, air would blow outwards from the oil gun nozzle hood. The cause was determined to be that the variable frequency vacuum pump only starts after receiving a refueling pulse or digital signal, not a gun lifting signal, resulting in a delay. When the tank pressure is higher than the oil tank opening pressure, oil vapor will also backflow from the oil gun nozzle hood.

[0025] To solve the above problems, the control program of the oil and gas recovery vacuum pump needs to be changed.

[0026] 1. Lifting the ORVR vapor recovery refueling nozzle 3 triggers the refueling machine to start refueling and controls the opening of the fuel circuit solenoid valve and the fuel pump motor. After the vapor recovery control mainboard 10 detects the opening of the fuel circuit solenoid valve, the vapor recovery vacuum pump 8 enters a low-speed mode. Upon detecting a refueling pulse, the vapor recovery control mainboard 10 enters a mode to adjust the speed of the vapor recovery vacuum pump 8; and adjusts the speed of the vapor recovery vacuum pump 8 according to the detected refueling pulse speed to meet the gas-liquid ratio. This solves the problem of asynchronous start-up of the fuel and gas circuits, and the problem of vapor backflushing in ORVR mode. The secondary vapor recovery system for gas stations is compatible with both ORVR and non-ORVR modes. 2. If the vapor recovery control mainboard 10 fails to bring the vapor recovery vacuum pump 8 to the preset speed within 5 seconds, it determines that the current air path is blocked. At this point, it is assumed that refueling is being performed on the China VI B fuel tank, and the gas station's secondary vapor recovery system enters ORVR compatible mode. The vapor recovery control mainboard then enters low-speed mode. Upon detecting that the fuel circuit solenoid valve is closed, the vapor recovery control mainboard 10 shuts down the vapor recovery vacuum pump 8 and enters stop mode. This procedure solves the problem of abnormal wear caused by jamming or creeping of the vapor recovery vacuum pump in ORVR mode.

[0027] Through the implementation of the above scheme at pilot gas stations, the secondary vapor recovery system at gas stations has proven highly compatible with both on-board vapor recovery ORVR and non-ORVR modes, improving the recognition rate and accuracy of both modes, ensuring the normal service life of the vapor recovery vacuum pump, and achieving greater consistency between the fuel dispenser and the online monitoring of the gas-liquid ratio. As the number of China VI B vehicles increases and their market share reaches an inflection point, the pressure in gas station storage tanks will no longer rise abnormally, reducing vapor emissions and making the tertiary vapor recovery system unnecessary.

[0028] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the present invention as claimed, which is defined by the appended claims and their equivalents.

Claims

1. A secondary oil vapor recovery system for a gas station with ORVR compatibility, comprising an underground oil tank (1), a discharge pipe PV valve (2), an ORVR oil vapor recovery refueling nozzle (3), a China VI B vehicle (4), an ORVR fuel tank (5), an oil pump (6), a flow measurement converter (7), an oil vapor recovery vacuum pump (8), a metering and control main board (9), an oil vapor recovery control main board (10), an indicator device (11), a gas circuit switch valve (12), a gas circuit bypass (13), a pressure sensing device (14), a fuel tank opening nozzle retaining ring (15), a gas collection hood (16), and a nozzle head (17), characterized in that: The oil pump (6) and flow measurement converter (7) are respectively connected to the underground oil tank (1) and the ORVR oil and gas recovery refueling gun (3) through pipelines. The oil and gas recovery vacuum pump (8) is connected to the ORVR oil and gas recovery refueling gun (3) and the underground oil tank (1) through pipelines. The discharge pipe PV valve (2) is installed on the top of the underground oil tank (1). The metering and control main board (9), the oil and gas recovery control main board (10), and the indicator device (11) are respectively installed in the refueling machine. The metering and control main board (9) is electrically connected to the oil pump (6), the flow measurement converter (7), and the indicator device (11).

2. The ORVR-compatible secondary oil and gas recovery system for gas stations according to claim 1, characterized in that: The oil and gas recovery control main board (10) is electrically connected to the oil and gas recovery vacuum pump (8), the gas circuit switch valve (12), and the pressure sensing device (14). The ORVR oil and gas recovery refueling gun (3) is equipped with a nozzle (17), and a gas collection hood (16) is fitted on the outside of the nozzle (17). The end of the gas collection hood (16) is equipped with a tank opening gun retainer (15). The refueling gun is equipped with a pressure sensing device (14), a gas circuit switch valve (12), and a gas circuit bypass (13). The National VI B vehicle (4) is equipped with an ORVR fuel tank (5). When refueling, the ORVR oil and gas recovery refueling gun (3) is inserted into the tank opening of the ORVR fuel tank (5). The tank opening gun retainer (15) is fitted and sealed with the tank opening to form a closed recovery chamber.

3. The ORVR-compatible secondary oil and gas recovery system for gas stations according to claim 1, characterized in that: The oil and gas recovery control main board (10) automatically switches between ORVR compatible mode and traditional non-ORVR mode based on the gun lifting signal, the status of the oil circuit solenoid valve, the refueling pulse signal, the detection signal of the pressure sensing device (14) and the vacuum pump speed feedback, so as to achieve precise adaptation of oil and gas recovery for different vehicles.

4. The ORVR-compatible secondary oil and gas recovery system for gas stations according to claim 1, characterized in that: The ORVR oil and gas recovery refueling gun (3) has a gas collection cover (16) fitted on the outside of the nozzle (17) and a gun retainer (15) fixed at the end of the oil tank opening. When refueling, it fits tightly with the opening of the ORVR oil tank (5) to prevent oil and gas from escaping and improve the recovery efficiency.

5. A secondary oil and gas recovery system for gas stations in ORVR compatible mode according to claim 1, characterized in that: The ORVR vapor recovery refueling nozzle (3) is equipped with a pressure sensing device (14) which is electrically connected to the vapor recovery control main board (10) to detect the pressure status of the fuel tank in real time, providing a signal basis for vehicle type identification and mode switching.

6. A secondary oil and gas recovery system for gas stations in ORVR compatible mode according to claim 1, characterized in that: The ORVR oil and gas recovery refueling nozzle (3) is equipped with an air circuit switch valve (12) and an air circuit bypass valve (13). The air circuit switch valve (12) can control the air circuit to switch between the main channel and the bypass channel. The air circuit bypass valve (13) is used to adjust the return air volume so that the gas-liquid ratio is stable in the range of 0.00–0.50 in ORVR mode.

7. A secondary oil and gas recovery system for gas stations in ORVR compatible mode according to claim 1, characterized in that: Oil and gas recovery vacuum pump (8) start-up logic optimization: After the oil circuit solenoid valve is opened by lifting the gun, it immediately enters the low-speed pre-rotation mode instead of waiting for the refueling pulse signal to start, eliminating the start-up delay and completely solving the problem of oil and gas backflush caused by excessive tank pressure; ORVR mode control logic: The oil and gas recovery control motherboard (10) detects that the vacuum pump cannot reach the preset speed within 5 seconds, and determines that the gas path is blocked. The system forces the ORVR compatible mode to control the vacuum pump to run continuously at low speed without stopping, so as to avoid equipment wear caused by stalling, jamming, and crawling. Non-ORVR mode control logic: The pressure sensing device (14) detects positive pressure in the oil tank and the vacuum pump speed is normal and can reach the preset value. The system determines that it is a traditional vehicle, the main air passage is fully open, and the oil and gas recovery control motherboard (10) adjusts the vacuum pump speed according to the refueling pulse signal using PID algorithm to stabilize the gas-liquid ratio in the range of 1.00–1.

20.

8. A secondary oil and gas recovery system for gas stations in ORVR compatible mode according to claim 1, characterized in that: The control motherboard (9) is linked with the oil and gas recovery control motherboard (10) to synchronously control the start-up, shutdown and operation status of the oil pump (6) and the oil and gas recovery vacuum pump (8), ensuring that the oil circuit and the gas circuit operate in unison and improving system stability.

9. A secondary oil and gas recovery system for gas stations in ORVR compatible mode according to claim 1, characterized in that: The discharge pipe PV valve (2) is installed on the top of the underground oil tank (1) to regulate the pressure inside the tank, prevent oil and gas from being directly discharged into the atmosphere, balance the system pressure, and improve environmental protection and safety performance.

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