An oil and gas recovery metering device for a gas station

Abstract

The present invention provides an oil and gas recovery metering device for a gas station, and relates to the technical field of oil and gas separation. The oil and gas recovery metering device for a gas station comprises: a tube body, having a first port and a second port, and a low-pressure chamber, a mixing chamber and a centrifugal chamber are sequentially arranged in the tube body from the first port toward the second port; a tank body, connected to the second port; and a first air return mechanism, which is used to connect the tank body with the low-pressure chamber, so that the oil and gas in the tank are sucked into the low-pressure chamber from the tank body, and form a mixed oil and gas in the mixing chamber with the external oil and gas entering from the first port, and the mixed oil and gas enter the centrifugal chamber for centrifugal separation. The present invention can connect the tank body with the low-pressure chamber through the first air return mechanism, so that the oil and gas in the tank can be re-sucked into the low-pressure chamber, and the oil and gas in the tank and the external oil and gas form a mixed oil and gas in the mixing chamber and enter the centrifugal chamber for separation again, finally realizing multiple separations of the oil and gas in the tank, thereby increasing the oil yield per unit volume of oil and gas.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas separation, and in particular to an oil and gas recovery and metering device for a gas station. Background Art

[0002] At present, the smell of gasoline can often be smelled near gas stations. The reason for the smell of gasoline is that gasoline easily evaporates into the air. At this time, the air contains volatile organic matter collectively referred to as oil and gas. The highest concentration of oil and gas is in the oil storage tank and the fuel tank. Therefore, the process of oil spillage from tank trucks and refueling by cars at gas stations is the main source of oil and gas leakage. The leakage and uncontrolled emission of oil and gas bring the risk of fire and explosion to gas stations, and there are great safety hazards.

[0003] Since the amount of oil and gas emitted during the oil tanker oil discharge operation and the car refueling operation at a gas station is limited, the oil droplets and gas in the oil and gas can be separated by using a centrifugal separation method. However, most existing oil and gas centrifugal separation devices have poor efficiency in oil and gas separation, resulting in an unsatisfactory amount of oil per unit volume of oil and gas. Summary of the invention

[0004] In order to solve the above problems, the present invention provides an oil and gas recovery metering device for a gas station.

[0005] The present invention provides an oil and gas recovery and metering device for a gas station, comprising: a tube body, having a first port and a second port, wherein a low-pressure chamber, a mixing chamber and a centrifugal chamber are sequentially arranged in the tube body from the first port toward the second port; a tank body, connected with the second port; and a first air return mechanism, which is used to connect the tank body with the low-pressure chamber, so that the oil and gas in the tank are sucked into the low-pressure chamber from the tank body, and mixed oil and gas are formed in the mixing chamber with the external oil and gas entering from the first port, and the mixed oil and gas enter the centrifugal chamber for centrifugal separation.

[0006] Optionally, the oil and gas recovery and metering device for a gas station also includes a negative pressure mixing centrifugal mechanism, which includes a conical block, a stirring blade and a centrifugal blade. The conical block is arranged in the low-pressure chamber, and a gap is formed between the outer peripheral surface of the conical block and the inner wall of the tube body. The stirring blade is rotatably arranged in the mixing chamber, and the centrifugal blade is rotatably arranged in the centrifugal chamber.

[0007] Optionally, the first air return mechanism includes an air inlet pipe, an air inlet channel is provided on the tube body, one end of the air inlet pipe is connected to the top of the inner cavity of the tank body, the other end of the air inlet pipe is connected to one end of the air inlet channel, and the other end of the air inlet channel is connected to the gap.

[0008] Optionally, the first air return mechanism also includes an oil float ring and a bellows, the oil float ring is arranged in the tank body, and the outer peripheral surface of the oil float ring is in sliding contact with the inner wall of the tank body, one end of the bellows is connected to the oil float ring, and the other end of the bellows is connected to the bottom end of the air inlet pipe, and the outer wall of the bellows is provided with a plurality of air holes from top to bottom, and the plurality of air holes are respectively arranged at the troughs at different positions on the outer wall of the bellows.

[0009] Optionally, the inner top surface of the tank body is provided with a cylindrical groove, and at least a portion of the upper pipe section of the corrugated pipe is accommodated in the cylindrical groove.

[0010] Optionally, the oil and gas recovery and metering device for a gas station also includes a second air return mechanism, which includes an air extraction main pipe and an air extraction branch pipe, and an air outlet channel is provided on the pipe body. One end of the air extraction branch pipe is arranged in the centrifugal chamber, and the other end of the air extraction branch pipe is connected to one end of the air outlet channel, and the other end of the air outlet channel is connected to one end of the air extraction main pipe, and the other end of the air extraction main pipe is connected to the air inlet pipe.

[0011] Optionally, the second air return mechanism further includes a pressure relief valve, and the pressure relief valve is arranged on the air exhaust main pipe.

[0012] Optionally, the tank body is provided with an observation window arranged vertically, and the observation window is provided with scale lines.

[0013] Optionally, the oil and gas recovery metering device for a gas station also includes a rotating mechanism, which includes a driving unit and a rotating shaft. The driving unit is drivingly connected to the rotating shaft to drive the rotating shaft to rotate, and the conical block, the stirring blade and the centrifugal blade are sequentially mounted on the rotating shaft.

[0014] Optionally, the stirring blade includes a blade and a blade plate, two of the blade plates are mounted on the rotating shaft, and a plurality of blades are connected between opposite surfaces of the two blade plates.

[0015] The beneficial effects of the oil and gas recovery metering device for a gas station of the present invention are as follows: external oil and gas enter the low-pressure chamber, the mixing chamber and the centrifugal chamber in sequence from the first port, and are centrifugally separated in the centrifugal chamber, so that oil droplets are thrown onto the inner wall of the centrifugal chamber, and then enter the tank body. With the inflow of oil, the oil level gradually rises, and at the same time, the dissolved gas and volatile gas in the oil are released into the space inside the tank. The tank body can be connected with the low-pressure chamber through the first air return mechanism, so that the oil and gas in the tank can be re-absorbed into the low-pressure chamber, and the oil and gas in the tank and the external oil and gas form mixed oil and gas in the mixing chamber, thereby Instead, the oil and gas concentration entering the centrifugal chamber can be increased. A higher oil and gas concentration can make it easier for the oil droplets in the centrifugal chamber to be thrown out, thereby improving the separation efficiency. At the same time, during the mixing process, the small oil droplets in the oil and gas in the tank can coalesce with the oil droplets in the external oil and gas to form larger oil droplets. The larger oil droplets are more easily thrown to the wall of the centrifugal chamber under the action of centrifugal force, thereby further improving the separation efficiency until the oil level in the tank rises to a preset height. In this process, multiple separations of the oil and gas in the tank are achieved, thereby increasing the oil yield per unit volume of oil and gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of an oil and gas recovery metering device used in a gas station according to an embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the internal structure of a low-pressure chamber, a mixing chamber and a centrifugal chamber in an oil and gas recovery and metering device for a gas station according to an embodiment of the present invention;

[0018] Figure 3 This is a schematic structural diagram of a conical block and a stirring blade in an oil and gas recovery and metering device for a gas station according to an embodiment of the present invention;

[0019] Figure 4 This is a diagram showing the position of the air holes in the bellows of the oil and gas recovery and metering device used in a gas station according to an embodiment of the present invention.

[0020] Figure 5 It is a three-dimensional diagram of an oil and gas recovery metering device used in a gas station according to an embodiment of the present invention;

[0021] Figure 6 The present invention is a schematic diagram of the structure of a driving unit in an oil and gas recovery and metering device for a gas station according to an embodiment of the present invention.

[0022] Explanation of the reference numerals: 1. Tube body; 11. Low-pressure chamber; 12. Mixing chamber; 13. Centrifugal chamber; 14. Air inlet channel; 15. Air outlet channel; 2. Negative-pressure mixing centrifugal mechanism; 21. Conical block; 22. Stirring blade; 221. Blade; 222. Blade plate; 23. Centrifugal blade; 3. Rotating mechanism; 31. Drive unit; 32. Rotating shaft; 4. Tank body; 41. Scale line; 42. Cylindrical groove; 5. First air return mechanism; 51. Oil float ring; 52. Bellows; 521. Air hole; 53. Air inlet pipe; 6. Second air return mechanism; 61. Air exhaust main pipe; 62. Pressure relief valve; 63. Air exhaust branch pipe. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the description of this specification, the description with reference to the terms "embodiment", "one embodiment", "some embodiments", "exemplarily" and "one embodiment" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or embodiment are included in at least one embodiment or embodiment of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or embodiment. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or embodiments in a suitable manner.

[0026] The terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0027] The Z axis in the accompanying drawings represents the vertical direction, that is, the up and down position, and the positive direction of the Z axis represents the up, and the negative direction of the Z axis represents the down; the X axis in the accompanying drawings represents the horizontal direction, and is designated as the left and right position, and the positive direction of the X axis represents the right side, and the negative direction of the X axis represents the left side; the Y axis in the accompanying drawings represents the front and back position, and the positive direction of the Y axis represents the front side, and the negative direction of the Y axis represents the back side. It should also be noted that the aforementioned Z axis, Y axis, and X axis are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0028] An embodiment of the present invention provides an oil and gas recovery and metering device for a gas station, comprising: a tube body 1, having a first port and a second port, wherein a low-pressure chamber 11, a mixing chamber 12 and a centrifugal chamber 13 are sequentially arranged in the tube body 1 from the first port toward the second port; a tank body 4, connected to the second port; and a first air return mechanism 5, used to connect the tank body 4 with the low-pressure chamber 11, so that the oil and gas in the tank are sucked into the low-pressure chamber 11 from the tank body 4, and mixed with the external oil and gas entering from the first port in the mixing chamber 12 to form a mixed oil and gas, and the mixed oil and gas enters the centrifugal chamber 13 for centrifugal separation.

[0029] Specifically, combined Figure 1 and Figure 2 As shown, the first port is one end of the tube body 1 along the positive direction of the Z axis, and the air intake pipe can be connected to the flange of the first port to facilitate the external oil and gas from the air intake pipe to be sent into the tube body 1 through the air pump. The second port is one end of the tube body 1 along the negative direction of the Z axis, and the direction from the first port to the second port is along the negative direction of the Z axis. The oil and gas in the tank refers to the oil and gas formed when the separated oil enters the tank body 4, and the external oil and gas refers to the oil and gas entering from the first port from the outside. The source of the external oil and gas can be the oil and gas escaped during the oil tanker oil discharge operation and the automobile refueling operation.

[0030] In this optional embodiment, external oil and gas enter the low-pressure chamber 11, the mixing chamber 12 and the centrifugal chamber 13 in sequence from the first port, and are centrifugally separated in the centrifugal chamber 13, so that the oil droplets are thrown onto the inner wall of the centrifugal chamber 13, and then enter the tank body 4. As the oil flows in, the oil level gradually rises, and at the same time, the dissolved gas and volatile gas in the oil are released into the space inside the tank. The tank body 4 can be connected with the low-pressure chamber 11 through the first air return mechanism 5, so that the oil and gas in the tank can be re-absorbed into the low-pressure chamber 11, and the oil and gas in the tank and the external oil and gas form mixed oil and gas in the mixing chamber 12, so that In order to increase the oil and gas concentration entering the centrifugal chamber 13, a higher oil and gas concentration can make it easier for the oil droplets in the centrifugal chamber 13 to be thrown out, thereby improving the separation efficiency. At the same time, during the mixing process, the small oil droplets in the oil and gas in the tank can be aggregated with the oil droplets in the external oil and gas to form larger oil droplets. The larger oil droplets are more easily thrown to the wall of the centrifugal chamber 13 under the action of centrifugal force, thereby further improving the separation efficiency until the oil level of the tank body 4 rises to a preset height. In this process, multiple separations of the oil and gas in the tank are achieved, thereby increasing the oil yield per unit volume of oil and gas.

[0031] Furthermore, the oil and gas recovery and metering device for gas stations also includes a negative pressure mixing centrifugal mechanism 2, which includes a conical block 21, a stirring blade 22 and a centrifugal blade 23. The conical block 21 is arranged in the low-pressure chamber 11, and a gap is formed between the outer peripheral surface of the conical block 21 and the inner wall of the tube body 1. The stirring blade 22 is rotatably arranged in the mixing chamber 12, and the centrifugal blade 23 is rotatably arranged in the centrifugal chamber 13.

[0032] In this optional embodiment, combined with Figure 2 As shown, the inner wall of the tube body 1 is integrally formed with a conical surface that matches the outer circumferential surface of the conical block 21, so that a gap is formed between the outer circumferential surface of the conical block 21 for oil and gas to pass through. As the flow rate of the oil and gas increases when passing through the gap, its pressure decreases accordingly, thereby forming a low-pressure cavity around the low-pressure chamber 11. The low pressure of the low-pressure cavity will cause the oil and gas in the tank to be sucked into the low-pressure chamber 11 from the first air return mechanism 5, thereby realizing the circulation and separation of the oil and gas in the tank.

[0033] Furthermore, the first air return mechanism 5 includes an air inlet pipe 53, an air inlet channel 14 is provided on the tube body 1, one end of the air inlet pipe 53 is connected to the top of the inner cavity of the tank body 4, the other end of the air inlet pipe 53 is connected to one end of the air inlet channel 14, and the other end of the air inlet channel 14 is connected to the gap.

[0034] In this optional embodiment, the low pressure formed in the low-pressure chamber 11 can suck the oil and gas at the top of the inner cavity of the tank body 4 into the low-pressure chamber 11 through the air intake pipe 53. By setting the bottom end of the air intake pipe 53 at the top of the inner cavity of the tank body 4, the air intake pipe 53 can always absorb the oil and gas in the tank even when the oil level rises.

[0035] Optionally, the first air return mechanism 5 also includes an oil float ring 51 and a bellows 52. The oil float ring 51 is arranged in the tank body 4, and the outer peripheral surface of the oil float ring 51 is in sliding contact with the inner wall of the tank body 4. One end of the bellows 52 is connected to the oil float ring 51, and the other end of the bellows 52 is connected to the bottom end of the air inlet pipe 53. The outer wall of the bellows 52 is provided with a plurality of air holes 521 from top to bottom, and the plurality of air holes 521 are respectively arranged at the troughs at different positions on the outer wall of the bellows 52.

[0036] In this optional embodiment, the density of the oil float ring 51 is smaller than that of the oil, so that it can rise and fall with the rise and fall of the oil level. The bellows 52 is set to a plastic material. When the oil level in the tank body 4 rises, the oil float ring 51 also moves up. Since the outer peripheral surface of the oil float ring 51 is in sliding contact with the inner wall of the tank body 4, it plays a guiding role in the upward movement of the oil float ring 51. In other words, the oil float ring 51 will not deviate radially (in the X-axis direction) during the upward movement, so the bellows 52 can also shrink and shorten in the vertical direction. In other words, the bellows 52 can be adaptively adjusted according to the height of the oil level, so that the multiple air holes 521 can always absorb the oil and gas in the tank above the oil surface, thereby improving the absorption rate of the oil and gas in the tank, thereby improving the efficiency of the oil and gas circulation separation in the tank.

[0037] It should be noted that the purpose of setting the oil float ring 51 in a ring shape is that, since the middle part of the oil float ring 51 is hollowed out, the lower oil port connecting the tank body 4 and the centrifugal chamber 13 can be set at the center of the top surface of the tank body 4. In this way, the oil can be dripped directly onto the liquid surface of the hollow part of the middle part of the oil float ring 51, avoiding the problem of oil dripping onto the oil float ring 51 and causing the oil to remain on the upper surface of the oil float ring 51.

[0038] Furthermore, a cylindrical groove 42 is provided on the inner top surface of the tank body 4 , and at least a portion of the upper pipe section of the bellows 52 is accommodated in the cylindrical groove 42 .

[0039] In this optional embodiment, when the bellows 52 is extended or retracted, the cylindrical groove 42 can guide the bellows 52 to avoid radial (X-axis direction) deviation of the bellows 52 when it is extended or retracted, thereby ensuring that the air hole 521 can open and close normally.

[0040] Furthermore, the oil and gas recovery and metering device for gas stations also includes a second air return mechanism 6, which includes an air extraction main pipe 61 and an air extraction branch pipe 63. An air outlet channel 15 is provided on the pipe body 1. One end of the air extraction branch pipe 63 is arranged in the centrifugal chamber 13, and the other end of the air extraction branch pipe 63 is connected to one end of the air outlet channel 15. The other end of the air outlet channel 15 is connected to one end of the air extraction main pipe 61, and the other end of the air extraction main pipe 61 is connected to the air intake pipe 53.

[0041] In this optional embodiment, combined with Figure 1 , Figure 2 and Figure 4 As shown, the end of the suction branch pipe 63 extends into the centrifugal chamber 13 but cannot interfere with the rotation path of the centrifugal blade 23. After the oil and gas are centrifuged, the separated gas can be sucked into the outlet channel 15 by multiple suction branch pipes 63, and then sucked into the intake pipe 53 through the suction main pipe 61, and finally enter the mixing chamber 12 to mix with the external oil and gas, and then separated again, thereby realizing the process of circulating and separating the separated gas in the centrifugal chamber 13, and improving the separation efficiency of the oil and gas. At the same time, since the air hole 521 is set at the trough of the outer wall of the bellows 52, when the oil level rises, the amount of oil and gas in the tank also decreases, and the bellows 52 contracts so that the trough is gradually sandwiched between two adjacent wave peaks, so that the air hole 521 is The orifice 21 gradually becomes smaller, thereby reducing the amount of oil and gas sucked into the tank by the bellows 52, and also reducing the amount of oil and gas sent into the low-pressure chamber by the air intake pipe 53. Since the flow rate of oil and gas entering the gap is constant, the amount of gas sucked into the low-pressure chamber is constant. At this time, the exhaust main pipe 61 needs to increase the amount of gas fed into the air intake pipe 53, thereby increasing the amount of gas sucked into the centrifugal chamber 13 by the exhaust branch pipe 63. In other words, when the oil level in the tank body 4 gradually increases and the amount of oil and gas in the tank decreases, the bellows 52 can adaptively reduce the amount of oil and gas sucked into the tank, and the exhaust branch pipe 63 can adaptively increase the amount of gas sucked into the centrifugal chamber 13. Through reasonable oil and gas circulation configuration, the oil and gas separation efficiency is comprehensively improved.

[0042] Optionally, the second air return mechanism 6 further includes a pressure relief valve 62 , and the pressure relief valve 62 is arranged on the air extraction main pipe 61 .

[0043] In this optional embodiment, combined with Figure 1 and Figure 2 As shown, since the first air return mechanism 5 and the second air return mechanism 6 both circulate the separated gas, the gas pressure in the centrifugal chamber 13 becomes larger and larger. When the gas pressure in the centrifugal chamber 13 exceeds the preset value, part of the gas will pass through the pressure relief valve 62 to the outside until the gas is discharged, and the other part continues to enter the intake pipe 53 through the exhaust main pipe 61. It should be noted that the oil content of the gas in the centrifugal chamber 13 after multiple centrifugation is extremely low, so it is a better choice to discharge the gas from the pressure relief valve 62 on the exhaust main pipe 61.

[0044] Optionally, the tank body 4 is provided with an observation window arranged vertically, and a scale line 41 is provided on the observation window.

[0045] In this optional embodiment, combined with Figure 5As shown, the observation window can be a vertical through groove opened in the tank body 4, and a strip of glass plate is encapsulated in the through groove to form an observation window. The scale line 41 on the observation window can display the oil level in the tank body 4, realizing the function of real-time measurement. In other optional embodiments, the tank body 4 can be made of a transparent material, so that the scale line 41 can be directly set from top to bottom on the outer surface of the tank body 4.

[0046] Furthermore, the oil and gas recovery metering device for a gas station also includes a rotating mechanism 3, which includes a driving unit 31 and a rotating shaft 32. The driving unit 31 is drivingly connected to the rotating shaft 32 to drive the rotating shaft 32 to rotate, and the conical block 21, the stirring blade 22 and the centrifugal blade 23 are sequentially mounted on the rotating shaft 32.

[0047] In this optional embodiment, combined with Figure 1 , Figure 2 , Figure 5 and Figure 6 As shown, both ends of the rotating shaft 32 can be rotatably mounted on the inner wall of the tube body 1 through bearings and mounting frames, and the rotating shaft 32 is coaxially arranged with the tube body 1. The rotating mechanism 3 can be composed of a motor and a gear set. The motor is fixedly mounted on the outer wall of the tube body 1, and the output shaft of the motor is connected to the rotating shaft 32 through the gear set. In other optional embodiments, the rotating mechanism 3 can also be composed of a motor and a pulley set. The motor is connected to the rotating shaft 32 through a pulley and a belt. The above two embodiments of the rotating mechanism 3 can realize the rotation of the rotating shaft 32, and the conical block 21, the stirring blade 22 and the centrifugal blade 23 can be fixedly mounted on the rotating shaft 32 by a key connection.

[0048] Furthermore, the stirring blade 22 includes a blade 221 and a blade plate 222 . The two blade plates 222 are mounted on the rotating shaft 32 , and the plurality of blades 221 are connected between opposite surfaces of the two blade plates 222 .

[0049] In this optional embodiment, combined with Figure 3 As shown, the two blades 222 can be fixedly mounted on the rotating shaft 32 by key connection, and a certain distance is reserved between the two blades 222, and the two blades 222 can be in a triangular structure, so that the blade 222 has three angular ends arranged at equal angles, and the corresponding blades 221 are also provided with three, and the two ends of the three blades 221 are respectively fixedly connected to the upper and lower staggered angular ends of the two blades 222, so that the three blades 222 are in a twisted posture. In this way, the three blades 222 in a twisted posture can increase the disturbance of the oil and gas in the tank and the external oil and gas when rotating, so that the oil and gas in the tank and the external oil and gas can be quickly mixed into mixed oil and gas.

[0050] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. An oil and gas recovery metering device for a gas station, characterized in that: include: A tube body (1) having a first port and a second port, wherein a low-pressure chamber (11), a mixing chamber (12) and a centrifugal chamber (13) are sequentially arranged in the tube body (1) in a direction from the first port toward the second port; a tank body (4) communicating with the second port; and A first air return mechanism (5) is used to connect the tank body (4) with the low-pressure chamber (11), so that the oil and gas in the tank are sucked from the tank body (4) into the low-pressure chamber (11), and mixed with the external oil and gas entering from the first port to form mixed oil and gas in the mixing chamber (12), and the mixed oil and gas enters the centrifugal chamber (13) for centrifugal separation; The oil and gas recovery metering device for a gas station further comprises a negative pressure mixing centrifugal mechanism (2), the negative pressure mixing centrifugal mechanism (2) comprising a conical block (21), a stirring blade (22) and a centrifugal blade (23), the conical block (21) being arranged in the low pressure chamber (11), and a gap being formed between the outer peripheral surface of the conical block (21) and the inner wall of the tube body (1), the stirring blade (22) being rotatably arranged in the mixing chamber (12), and the centrifugal blade (23) being rotatably arranged in the centrifugal chamber (13); The first air return mechanism (5) comprises an air intake pipe (53), an air intake channel (14) is provided on the pipe body (1), one end of the air intake pipe (53) is in communication with the top of the inner cavity of the tank body (4), the other end of the air intake pipe (53) is in communication with one end of the air intake channel (14), and the other end of the air intake channel (14) is in communication with the gap; The first air return mechanism (5) further comprises an oil float ring (51) and a bellows (52); the oil float ring (51) is arranged in the tank body (4), and the outer peripheral surface of the oil float ring (51) is in sliding contact with the inner wall of the tank body (4); one end of the bellows (52) is connected to the oil float ring (51), and the other end of the bellows (52) is connected to the bottom end of the air inlet pipe (53); the outer wall of the bellows (52) is provided with a plurality of air holes (521) from top to bottom, and the plurality of air holes (521) are respectively arranged at wave troughs at different positions on the outer wall of the bellows (52).

2. The oil and gas recovery metering device for a gas station as claimed in claim 1, characterized in that: The inner top surface of the tank body (4) is provided with a cylindrical groove (42), and at least a portion of the upper pipe section of the bellows (52) is accommodated in the cylindrical groove (42).

3. The oil and gas recovery metering device for a gas station as claimed in claim 1, characterized in that: The oil and gas recovery metering device for a gas station further comprises a second air return mechanism (6), the second air return mechanism (6) comprising an air extraction main pipe (61) and an air extraction branch pipe (63), an air outlet channel (15) being provided on the pipe body (1), one end of the air extraction branch pipe (63) being arranged in the centrifugal chamber (13), the other end of the air extraction branch pipe (63) being communicated with one end of the air outlet channel (15), the other end of the air outlet channel (15) being communicated with one end of the air extraction main pipe (61), and the other end of the air extraction main pipe (61) being communicated with the air inlet pipe (53).

4. The oil and gas recovery metering device for a gas station as claimed in claim 3, characterized in that: The second air return mechanism (6) further comprises a pressure relief valve (62), wherein the pressure relief valve (62) is arranged on the air extraction main pipe (61).

5. The oil and gas recovery metering device for a gas station as claimed in claim 1, characterized in that: The tank body (4) is provided with an observation window arranged vertically, and the observation window is provided with scale lines (41).

6. The oil and gas recovery metering device for a gas station as claimed in claim 1, characterized in that: The invention also comprises a rotating mechanism (3), wherein the rotating mechanism (3) comprises a driving unit (31) and a rotating shaft (32), wherein the driving unit (31) is drivingly connected to the rotating shaft (32) so as to drive the rotating shaft (32) to rotate, and the conical block (21), the stirring blade (22) and the centrifugal blade (23) are sequentially mounted on the rotating shaft (32).

7. The oil and gas recovery metering device for a gas station as claimed in claim 6, characterized in that: The stirring blade (22) comprises a blade (221) and a blade plate (222); two blade plates (222) are sleeved on the rotating shaft (32); and a plurality of blades (221) are connected between opposite surfaces of the two blade plates (222).

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