Vacuum measuring device for vacuum pump

Abstract

The vacuum measuring device for the vacuum pump comprises a vacuum gauge and an air inlet mechanism, the air inlet mechanism is communicated with the vacuum pump, and the vacuum gauge is used for measuring the vacuum degree in the air inlet mechanism; the air inlet mechanism is provided with at least one air inlet connector, the at least one air inlet connector is close to the connecting position of the vacuum gauge and the air inlet mechanism, the air inlet connector can be communicated with the external environment, and the air inlet connector is used for guiding air into the air inlet mechanism. According to the vacuum measuring device for the vacuum pump, the vacuum gauge and the air inlet mechanism are arranged, the air inlet mechanism is communicated with the air exhaust channel of the vacuum pump, and the vacuum gauge can be communicated with the vacuum pump through the air inlet mechanism, so that the pressure in the compressor tank is measured; the air inlet connector can convey external air into the air inlet mechanism, and when the vacuum pump exhausts air, macromolecules in the external air can take away light fractions near the vacuum gauge, so that the measurement influence of the light fractions on the vacuum gauge is reduced, the measurement error is reduced, and the measurement accuracy is improved.

Description

Technical Field

[0001] This application relates to the field of vacuum pump technology, and specifically to a vacuum measuring device for a vacuum pump. Background Technology

[0002] In the current refrigerator and air conditioner manufacturing process, the refrigerant compressor tank needs to be evacuated to a certain pressure using a vacuum pump before refrigerant can be injected to achieve the cooling effect.

[0003] However, due to the presence of a small amount of compressor oil remaining in the refrigerant compressor tank and its connecting copper pipes, this oil vaporizes into gas during the evacuation process. This gas is then drawn into the vacuum system piping and the vacuum pump itself. Because the gaseous compressor oil contains trace amounts of very small molecular weight components, and these small gaseous molecules are difficult for the vacuum pump to remove, the rebound effect of vacuum pressure causes these light distillate molecules to directly increase the molecular weight measured by the vacuum gauge. This results in an inflated vacuum gauge reading and thus an error in the vacuum gauge reading, affecting the acceptance criteria of the compressor tank.

[0004] Therefore, there is room for further improvement in the existing technology for measuring the vacuum level of vacuum pumps. Utility Model Content

[0005] In view of this, and in response to the technical problem in the prior art that the measurement of vacuum degree in a vacuum pump is affected by light distillate molecules generated by the compressor oil, this application provides a vacuum measuring device for a vacuum pump, which is equipped with an air inlet mechanism that can continuously leak a certain amount of ambient air into the pumping pipe. This allows the large atmospheric molecules entering the pipe to carry away the light distillate molecules in the pumped container during the process of being pumped away by the vacuum pump, thereby reducing the influence of light distillate molecules on the vacuum gauge measurement and improving the measurement accuracy.

[0006] This application provides a vacuum measuring device for a vacuum pump, characterized in that it includes a vacuum gauge and an air intake mechanism, wherein the air intake mechanism is connected to the vacuum pump, and the vacuum gauge is used to measure the vacuum level inside the air intake mechanism;

[0007] The air intake mechanism is provided with at least one air intake connector, which is located near the connection between the vacuum gauge and the air intake mechanism. The air intake connector is able to communicate with the external environment and is used to guide air into the air intake mechanism.

[0008] Compared with the prior art, the vacuum measuring device for vacuum pumps provided in this application is equipped with a vacuum gauge and an air intake mechanism. The air intake mechanism is connected to the air pumping channel of the vacuum pump, and the vacuum gauge can be connected to the vacuum pump through the air intake mechanism to measure the pressure inside the compressor tank.

[0009] In this application, the air intake mechanism is equipped with an air intake connector, which can deliver external air to the air intake mechanism. When the vacuum pump is pumping air, the large molecules in the external air can carry away the light distillate molecules near the vacuum gauge, reducing the influence of light distillate molecules on the measurement of the vacuum gauge, reducing measurement error, and improving measurement accuracy.

[0010] Preferably, the air intake mechanism includes a converter cylinder and an air outlet pipe, and the converter cylinder is connected to the air extraction pipe of the vacuum pump through the air outlet pipe;

[0011] The vacuum gauge is connected to the end of the converter cylinder away from the outlet pipe.

[0012] Preferably, the air inlet connector includes a connecting pipe and an air inlet pipe, the connecting pipe is connected to the converter cylinder, and the air inlet pipe is sleeved on the end of the connecting pipe away from the converter cylinder;

[0013] The air intake pipe is provided with an air intake hole, which penetrates the air intake pipe along the axial direction of the air intake pipe.

[0014] Preferably, the intake pipe includes a first hole, a second hole, and a third hole connected in sequence, wherein the diameter of the first hole is R1, the diameter of the second hole is R2, and the diameter of the third hole is R3, wherein R1 <R2<R3。

[0015] Preferably, the air inlet is located between the first hole and the second hole, and the diameter of the air inlet is R. <R1;

[0016] Wherein, along the axial direction of the air inlet connector, the end of the first hole near the air inlet is provided with a first conical guide surface;

[0017] The second hole portion has a second conical guide surface at the end near the air inlet;

[0018] The end of the third hole near the air inlet is provided with a third conical guide surface.

[0019] Preferably, the connecting pipe has a connecting part and a mounting part, the mounting part is connected to the connecting part, the mounting part is disposed in the third hole, and the connecting part is connected to the converter cylinder;

[0020] The outer diameter of the connecting part is R4, and the outer diameter of the mounting part is R5, where R5>R4 and R5>R3;

[0021] The end of the mounting part has a tapered structure.

[0022] Preferably, the air intake mechanism is provided with two air intake connectors, namely a first air intake connector and a second air intake connector;

[0023] The first air inlet connector is located at the end of the converter cylinder away from the air outlet pipe, and the first air inlet connector is connected to the converter cylinder;

[0024] The second air inlet connector is located at the side end of the air outlet pipe, and the second air inlet connector is connected to the air outlet pipe.

[0025] Preferably, it also includes a plug for sealing the air intake connector from the external environment.

[0026] Preferably, the converter cylinder includes a first cylinder and a second cylinder, wherein the first cylinder and the second cylinder are coaxially connected;

[0027] The first cylinder body is provided with a first connecting plate, and the first connecting plate is provided with a first connecting hole;

[0028] The second cylinder is provided with a second connecting plate, and the second connecting plate is provided with a second connecting hole;

[0029] The first connecting hole and the second connecting hole are coaxially arranged to allow the same connector to be inserted, so as to realize the connection between the first cylinder and the second cylinder.

[0030] Preferably, the exhaust pipe and the converter cylinder are made of metal.

[0031] The axis of the exhaust pipe and the converter cylinder are on the same straight line, and the diameter of the exhaust pipe is smaller than the diameter of the converter cylinder.

[0032] The vacuum measuring device for a vacuum pump disclosed in this application has at least the following technical advantages:

[0033] 1. By setting up an air intake mechanism and installing an air intake connector on the air intake mechanism, which is connected to the external environment, the air intake mechanism can introduce external air. This allows the vacuum pump to carry away the light distillation molecules near the vacuum gauge when the vacuum pump is pumping air, thereby reducing the influence of light distillation molecules on the measurement of the vacuum gauge, reducing measurement error, and improving measurement accuracy.

[0034] 2. By setting up an exchange cylinder and an outlet pipe, with the outlet pipe and vacuum gauge respectively located at both ends of the exchange cylinder, when the vacuum pump is pumping air, light distillate molecules near the vacuum gauge can be drawn into the vacuum pump relatively quickly.

[0035] 3. By setting a plug, the air inlet can be blocked when air leakage is not required, to meet matching usage needs. Attached Figure Description

[0036] Figure 1 This is a three-dimensional structural schematic diagram of a vacuum measuring device for a vacuum pump provided in an embodiment of this application;

[0037] Figure 2 This is a partial cross-sectional structural schematic diagram of a vacuum measuring device for a vacuum pump provided in an embodiment of this application;

[0038] Figure 3 yes Figure 1 A magnified view of part A;

[0039] Figure 4 yes Figure 2 A magnified view of part B;

[0040] Figure 5 This is a partial structural schematic diagram of the air intake pipe provided in one embodiment of this application.

[0041] Reference numerals: 1. Intake mechanism; 2. Vacuum gauge; 3. Vacuum pump;

[0042] 11. Air inlet connector; 12. Converter cylinder; 13. Air outlet pipe; 14. First air inlet connector; 15. Second air inlet connector;

[0043] 111. Connecting pipe; 112. Intake pipe;

[0044] 1111. Mounting part; 1112. Connecting part;

[0045] 1121. Air inlet; 1122. First hole section; 1123. Second hole section; 1124. Third hole section; 1125. First conical guide surface; 1126. Second conical guide surface; 1127. Third conical guide surface;

[0046] 121. First cylinder; 122. Second cylinder; 123. First connecting plate; 124. Second connecting plate. Detailed Implementation

[0047] To enable those skilled in the art to better understand the technical solutions of this disclosure, the following detailed, clear, and complete description of this disclosure is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this disclosure and are not intended to limit it.

[0048] In the description of this application, the use of "first" and "second" is for the purpose of distinguishing technical features only, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0049] Those skilled in the art should understand that in the disclosure of this application, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on this application.

[0050] The present application will now be described in further detail with reference to the accompanying drawings, see below. Figures 1 to 5 illustrate.

[0051] This application provides a vacuum measuring device for a vacuum pump (hereinafter referred to as the measuring device). The measuring device is connected to the pumping pipe of the vacuum pump 3. When the vacuum pump 3 evacuates the compressor or other equipment, the measuring device can measure the vacuum level inside the compressor or other equipment, so that the staff can promptly observe whether the vacuum level of the compressor or other equipment has met the target.

[0052] Specifically, such as Figure 1 As shown, the measuring device includes a vacuum gauge 2 and an air intake mechanism 1. The bottom of the air intake mechanism 1 is connected to a vacuum pump 3, and the top is connected to the vacuum gauge 2. The vacuum gauge 2 can measure the vacuum level inside the air intake mechanism 1 through the air intake mechanism 1; wherein, as... Figure 3 As shown, the air intake mechanism 1 is provided with at least one air intake connector 11. The air intake connector 11 can communicate with the external environment. The air intake connector 11 is used to guide air into the air intake mechanism 1. Thus, when the vacuum pump 3 is pumping air, the large molecules in the external air can carry away the light distillation molecules near the vacuum gauge 2, reduce the influence of light distillation molecules on the measurement of the vacuum gauge 2, reduce the measurement error, and improve the measurement accuracy.

[0053] At least one air inlet connector 11 is located near the connection between the vacuum gauge 2 and the air inlet mechanism 1, that is, at least one air inlet connector 11 is located on the top of the air inlet mechanism 1, close to the vacuum gauge 2. This increases the probability of light distillate molecules near the vacuum gauge 2 coming into contact with the outside air. Consequently, when the vacuum pump 3 pumps air, the probability of light distillate molecules near the vacuum gauge 2 being carried away by large molecules in the outside air increases, thereby improving the measurement accuracy of the vacuum gauge 2.

[0054] Furthermore, such as Figures 1 to 3As shown, the air intake mechanism 1 includes an air exchanger cylinder 12 and an air outlet pipe 13. The air exchanger cylinder 12 is a cylindrical structure, and the air exchanger cylinder 12 and the air outlet pipe 13 are coaxially arranged. The air outlet pipe 13 is a tubular structure, and its inner diameter is smaller than that of the air exchanger cylinder 12. The air outlet pipe 13 is connected to the bottom of the air exchanger cylinder 12, and the vacuum gauge 2 is connected to the top of the air exchanger cylinder 12. The air exchanger cylinder 12 is connected to the suction pipe of the vacuum pump 3 through the air outlet pipe 13. The air exchanger cylinder 12 is mainly used to accommodate the gas entering from the outside and to allow the external gas to come into contact with the light distillate molecules near the vacuum gauge 2, thereby reducing the influence of the light distillate molecules on the measurement of the vacuum gauge 2 and reducing the error of the acceptance index of the compressor tank.

[0055] Among them, such as Figure 4 As shown, the converter tube 12 is provided with an interface for the insertion of the vacuum gauge 2.

[0056] It should be noted that in this application, the converter 12 can be configured as an integral structure or as a split structure; wherein, for example Figures 1 to 3 As shown, the converter cylinder 12 has a split structure, consisting of two parts: a first cylinder 121 and a second cylinder 122. The first cylinder 121 and the second cylinder 122 are coaxially connected, and the inner diameter of the first cylinder 121 is the same as that of the second cylinder 122. The lower end of the first cylinder 121 is connected to the upper end of the second cylinder 122. The vacuum gauge 2 is connected to the upper end of the first cylinder 121, and the exhaust cylinder is connected to the lower end of the second cylinder 122. By setting the converter cylinder 12 as a split structure, the manufacturing difficulty of the converter cylinder 12 can be simplified and the manufacturing cost can be reduced.

[0057] Furthermore, such as Figure 2 , Figure 3 As shown, a first connecting plate 123 is provided on the outer side of the first cylinder 121 near the end of the second cylinder 122. The end face of the first connecting plate 123 is flush with the end face of the first cylinder 121. The first connecting plate 123 has an annular structure and the first connecting plate 123 and the first cylinder 121 can be integrally formed. The first connecting plate 123 is provided with a first connecting hole, which penetrates the first connecting plate 123 axially. There are multiple first connecting holes, which are circumferentially equidistantly distributed.

[0058] Similarly, a second connecting plate 124 is provided on the outer end of the second cylinder 122 near the end of the first cylinder 121. The end face of the second connecting plate 124 is flush with the end face of the second cylinder 122. The second connecting plate 124 has an annular structure and the second connecting plate 124 and the second cylinder 122 can be integrally formed. The second connecting plate 124 is provided with a second connecting hole, which penetrates the second connecting plate 124 axially. There are multiple second connecting holes, which are circumferentially equidistantly distributed.

[0059] The first connecting hole and the second connecting hole are coaxially arranged to allow the same connector to be inserted. In this embodiment, the connector is preferably a screw or bolt, which, together with a nut, locks the first connecting plate 123 and the second connecting plate 124 to achieve the connection between the first cylinder 121 and the second cylinder 122.

[0060] In addition, a sealing ring is provided between the ends of the first connecting plate 123 and the second connecting plate 124 near the center of the axis to achieve a sealed connection between the first cylinder 121 and the second cylinder 122.

[0061] like Figure 1 , Figures 2 to 3 As shown in this application, the axes of the outlet pipe 13 and the converter cylinder 12 are on the same straight line. The inner diameter of the converter cylinder 12 is larger than the inner diameter of the outlet pipe 13. With this structural arrangement, when the gas in the converter cylinder 12 enters the outlet pipe 13, the flow rate increases, so that the large molecules in the external air in the converter cylinder 12 can carry the light distillation molecules to the outlet pipe 13 more quickly.

[0062] It should be noted that in this application, the gas outlet pipe 13 and the converter cylinder 12 are both made of metal materials; preferably aluminum, which has good corrosion resistance and can prevent light distillate molecules from affecting the measuring device.

[0063] In this application, the measuring device also includes a plug, which can seal the air inlet connector 11 to close the connection between the air inlet connector 11 and the external environment, so that the air intake mechanism 1 can meet the usage requirements of different situations. When the air intake mechanism 1 does not need to intake air, it can be closed to the external environment through the plug; when it is needed, the plug can be removed from the air inlet connector 11 to realize the connection between the air intake mechanism 1 and the external environment.

[0064] In this application, such as Figures 1 to 3 As shown, the air intake mechanism 1 is equipped with two air intake connectors 11, namely a first air intake connector 14 and a second air intake connector 15. The first air intake connector 14 is connected to the converter cylinder 12, and is located on the top of the converter cylinder 12 and at the side end of the vacuum gauge 2. The axis of the first air intake connector 14 is parallel to the converter cylinder 12. The second air intake connector 15 is located at the side end of the outlet pipe 13, and is connected to the outlet pipe 13. The axis of the second air intake connector 15 is perpendicular to the axis of the outlet pipe 13. In this application, the first air intake connector 14 and the second air intake connector 15 have the same structure, only their positions and directions are different, which can provide different air intake requirements for the measuring device. In actual use, any one or both can be opened according to the usage requirements.

[0065] Based on any of the above embodiments, the structure of the air intake connector 11 will be further described; such as Figure 4 , Figure 5 As shown in the figure, the intake joint 11 includes a connecting pipe 111 and an intake pipe 112. Both the intake pipe 112 and the connecting pipe 111 are tubular structures. The connecting pipe 111 is connected to the commutation cylinder 12. The connecting pipe 111 and the commutation cylinder 12 can be integrally formed or separately connected. Among them, the intake pipe 112 is sleeved on the end of the intake pipe 112 far from the commutation cylinder 12, and there is an interference fit between the intake pipe 112 and the connecting pipe 111, so as to ensure the tightness of the connection between the intake pipe 112 and the connecting pipe 111.

[0066] Among them, as Figure 4 、 Figure 5 shown in the figure, the intake pipe 112 is provided with intake holes 1121. The intake holes 1121 penetrate through the intake pipe 112 along the axial direction of the intake pipe 112. The intake holes 1121 are set to be relatively small, so as to ensure the extremely low air leakage performance of the intake joint 11 and avoid the influence on the pumping pressure of the vacuum pump 3 due to the excessive size of the intake holes 1121. [[ID=X]]

[0067] Specifically, the aperture of the intake holes 1121 is set between 0.01 mm and 0.02 mm. Of course, the size of the intake holes 1121 can be selected according to actual needs, but the overall aperture of the intake holes 1121 is relatively small to ensure the extremely low air leakage performance.

[0068] As Figure 5 shown in the figure, the intake pipe 112 includes a first hole part 1122, a second hole part 1123 and a third hole part 1124 arranged in sequence. The intake holes 1121 are arranged between the first hole part 1122 and the second hole part 1123. The first hole part 1122, the intake holes 1121, the second hole part 1123 and the third hole part 1124 are arranged in sequence along the axial direction of the intake pipe 112. The first hole part 1122 opens on the outer end face of the intake pipe 112, and the third hole part 1124 opens on the end face where the intake pipe 112 is connected to the connecting pipe 111. And the connecting pipe 111 is arranged in the third hole part 1124 to realize the connection between the connecting pipe 111 and the intake pipe 112.

[0069] Among them, the aperture of the first hole part 1 is R1, the aperture of the second hole part 1123 is R2, the aperture of the third hole part 1124 is R3, and the aperture of the intake holes 1121 is R. Among them, R < R1 < R2 < R3. Thus, when the external air flows from the first hole part 1122 to the intake holes 1121, due to the decrease in the flow diameter, the flow velocity increases, so that the gas entering the first hole part 1 can flow into the intake holes 1121 relatively quickly. When the gas in the intake holes 1121 flows to the second hole part 1123, the diameters of the second hole part 1123 and the third hole part 1124 gradually increase, and the gas will become stable, avoiding disorder and reducing the influence on the operation of the vacuum pump 3.

[0070] Furthermore, as Figure 5As shown, along the axial direction of the air inlet connector 11, the end of the first hole 1122 near the air inlet 1121 is provided with a first conical guide surface 1125. The first conical guide surface 1125 can slow down the flow of gas from the first hole 1122 to the air inlet 1121, thus moderating the change in gas flow velocity and reducing the adverse effects of abrupt changes in the orifice size, making the gas flow more stable. Similarly, the end of the second hole 1123 near the air inlet 1121 is provided with a second conical guide surface. 1126. The end of the third hole 1124 near the air inlet 1121 is provided with a third conical guide surface 1127. The functions of the second conical guide surface 1126 and the third conical guide surface 1127 are the same as those of the first conical guide surface 1125. They all serve as buffers and connectors, and can stabilize the gas flow entering the air inlet pipe 112, reduce the impact of gas on the air inlet pipe 112 and the converter cylinder 12, ensure the operational stability of the measuring device, and make the measurement environment of the vacuum gauge 2 more stable.

[0071] Furthermore, such as Figure 4 As shown, the connecting pipe 111 has a connecting part 1112 and a mounting part 1111. The mounting part 1111 is connected to the connecting part 1112 and is located inside the third hole 1124. The connecting part 1112 is connected to the converter cylinder 12. The outer diameter of the connecting part 1112 is R4, and the outer diameter of the mounting part 1111 is R5, where R5>R4 and R5>R3. That is, the outer diameter of the mounting part 1111 is larger than that of the connecting part 1112, ensuring the structural strength of the mounting part 1111. The mounting part 1111 is inserted into the third hole 1124 to connect the connecting pipe 111 to the air intake pipe 112. The outer diameter of the mounting part 1111 is larger than the diameter of the third hole 1124, thereby achieving an interference fit between the mounting part 1111 and the third hole 1124, ensuring the connection stability between the air intake pipe 112 and the connecting pipe 111.

[0072] Furthermore, such as Figure 4 As shown, both ends of the mounting part 1111 are designed with a tapered structure, meaning the side end face of the mounting part 1111 is inclined to the axis, reducing stress concentration on the end face of the mounting part 1111, improving the structural strength of the mounting part 1111, and extending the service life of the connecting pipe 111. Furthermore, as... Figure 4 As shown, the inner diameter of the mounting part 1111 is smaller than the inner diameter of the third hole part 1124, so that the gas in the intake pipe 112 can quickly enter the converter cylinder 12 through the connecting pipe 111.

[0073] Meanwhile, the conical structure facing the third hole 1124 of the mounting part 1111 can guide the fluid; with the air intake direction as the positive direction, the conical surfaces of the first conical guide surface 1125 and the conical structure of the mounting part 1111 located in the third hole 1124 are both facing the positive direction, while the conical surfaces of the second conical guide surface 1126 and the third conical guide surface 1127 are both facing the opposite direction.

[0074] It should be noted that the various embodiments of this application can be arbitrarily combined into new embodiments, provided that the solutions do not conflict and the technical solutions can coexist.

[0075] The present application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present application. The descriptions of the embodiments above are only for the purpose of helping to understand the present application and its core ideas. It should be noted that those skilled in the art can make several improvements and modifications to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A vacuum measuring device for a vacuum pump, characterized in that, It includes a vacuum gauge (2) and an air intake mechanism (1), the air intake mechanism (1) being connected to a vacuum pump (3), and the vacuum gauge (2) being used to measure the vacuum level inside the air intake mechanism (1); The air intake mechanism (1) is provided with at least one air intake connector (11), wherein at least one air intake connector (11) is close to the connection between the vacuum gauge (2) and the air intake mechanism (1), the air intake connector (11) can communicate with the external environment, and the air intake connector (11) is used to guide air into the air intake mechanism (1).

2. The vacuum measuring device for a vacuum pump according to claim 1, characterized in that, The air intake mechanism (1) includes a converter cylinder (12) and an air outlet pipe (13). The converter cylinder (12) is connected to the air extraction pipe of the vacuum pump (3) through the air outlet pipe (13). The vacuum gauge (2) is connected to the end of the converter cylinder (12) away from the outlet pipe (13).

3. The vacuum measuring device for a vacuum pump according to claim 2, characterized in that, The air inlet connector (11) includes a connecting pipe (111) and an air inlet pipe (112). The connecting pipe (111) is connected to the converter cylinder (12), and the air inlet pipe (112) is sleeved on the end of the connecting pipe (111) away from the converter cylinder (12). The air intake pipe (112) is provided with an air intake hole (1121), which penetrates the air intake pipe (112) along the axial direction of the air intake pipe (112).

4. The vacuum measuring device for a vacuum pump according to claim 3, characterized in that, The intake pipe (112) includes a first hole (1122), a second hole (1123), and a third hole (1124) connected in sequence. The diameter of the first hole (1122) is R1, the diameter of the second hole (1123) is R2, and the diameter of the third hole (1124) is R3. <R2<R3。 5. The vacuum measuring device for a vacuum pump according to claim 4, characterized in that, The air inlet (1121) is disposed between the first hole (1122) and the second hole (1123), and the diameter of the air inlet (1121) is R. <R1; Wherein, along the axial direction of the air inlet connector (11), the end of the first hole (1122) near the air inlet (1121) is provided with a first conical guide surface (1125); The second hole (1123) is provided with a second conical guide surface (1126) at the end near the air inlet (1121); The third hole (1124) is provided with a third conical guide surface (1127) at the end near the air inlet (1121).

6. The vacuum measuring device for a vacuum pump according to claim 4, characterized in that, The connecting pipe (111) is provided with a connecting part (1112) and a mounting part (1111). The mounting part (1111) is connected to the connecting part (1112). The mounting part (1111) is disposed in the third hole (1124). The connecting part (1112) is connected to the converter cylinder (12). The outer diameter of the connecting part (1112) is R4, and the outer diameter of the mounting part (1111) is R5, where R5>R4 and R5>R3; The end of the mounting part (1111) is a tapered structure.

7. The vacuum measuring device for a vacuum pump according to claim 2, characterized in that, The air intake mechanism (1) is provided with two air intake connectors (11), namely the first air intake connector (14) and the second air intake connector (15); The first air inlet connector (14) is located at the end of the converter cylinder (12) away from the air outlet pipe (13), and the first air inlet connector (14) is connected to the converter cylinder (12); The second air inlet connector (15) is located at the side end of the air outlet pipe (13), and the second air inlet connector (15) is connected to the air outlet pipe (13).

8. The vacuum measuring device for a vacuum pump according to claim 1, characterized in that, It also includes a plug, which is used to seal the air intake connector (11) from the external environment.

9. The vacuum measuring device for a vacuum pump according to claim 2, characterized in that, The converter cylinder (12) includes a first cylinder (121) and a second cylinder (122), wherein the first cylinder (121) and the second cylinder (122) are coaxially connected. The first cylindrical body (121) is provided with a first connecting plate (123), and the first connecting plate (123) is provided with a first connecting hole; The second cylinder (122) is provided with a second connecting plate (124), and the second connecting plate (124) is provided with a second connecting hole; The first connecting hole and the second connecting hole are coaxially arranged to allow the same connector to be inserted, so as to realize the connection between the first cylinder (121) and the second cylinder (122).

10. The vacuum measuring device for a vacuum pump according to claim 2, characterized in that, The exhaust pipe (13) and the converter cylinder (12) are made of metal materials; The axis of the air outlet pipe (13) and the converter cylinder (12) are on the same straight line, and the diameter of the air outlet pipe (13) is smaller than the diameter of the converter cylinder (12).

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