Air-cooled Roots vacuum pump comprising pre-air-inlet flange

Abstract

The utility model relates to the technical field of Roots vacuum pumps, in particular to an air-cooled Roots vacuum pump comprising a pre-intake flange, which comprises an air-cooled Roots vacuum pump body. A cold air return pipeline; the at least one pre-air-inlet flange is arranged between the pump body and the cold air returning pipeline; the pre-air-inlet flange comprises a rectangular connecting flange which is of a rectangular frame structure, an open hole is formed in the middle of the rectangular connecting flange, and returned cold air flows into the pump body through the open hole; one end of the connecting pipe is connected with the outer edge of the opening of the rectangular connecting flange; the connecting pipe extends from inside to outside and is provided with a flow channel space, and the flow channel space is communicated with the open hole; the pipeline inner wall of the connecting pipe is of a streamline-shaped gradual change structure; the circular connecting flange is connected to the end, away from the rectangular connecting flange, of the connecting pipe, and a circular opening is formed in the circular connecting flange; and the circular opening, the runner space and the open pore are communicated. The airflow resistance is reduced, and the noise of the air-cooled Roots vacuum pump in the working process is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to roots vacuum pump technical field especially, relates to a kind of gas-cooled roots vacuum pump containing pre-intake flange. BACKGROUND

[0002] The limitation of ordinary roots vacuum pump is that it cannot be started under atmospheric pressure, cannot be operated under high pressure difference, and cannot be directly discharged to atmosphere. When ordinary roots vacuum pump works under large pressure difference and high pressure, a large amount of heat will be generated. If the excessive heat generated during the operation of the rotor cannot be dissipated, excessive expansion will occur, resulting in the disappearance of the gap between the rotor and the pump cavity, and further causing the rotor to be stuck. The increase of temperature in the pump cavity of the roots vacuum pump will affect the pumping speed and vacuum degree of the entire vacuum pump. The higher the temperature, the lower the pumping speed of the entire vacuum pump, and the lower the vacuum degree that can be achieved. Ordinary roots vacuum pump needs ordinary mechanical vacuum pump as a backing pump, so its use is limited, resulting in a narrow application range.

[0003] The gas-cooled roots vacuum pump, also known as pre-intake cold gas roots vacuum pump, sucks the gas to be pumped from the top and discharges it from the bottom. The exhaust port is connected to the gas-water heat exchanger installed below by a corrugated tube. The middle and lower parts of both sides of the pump are provided with cold gas return ports. Part of the gas discharged from the gas-cooled roots vacuum pump is cooled by the heat exchanger and then returned to the pump cavity through a pipeline to cool the rotor, and the other part of the gas is directly discharged to atmosphere after being cooled by the heat exchanger. The gas-cooled roots vacuum pump pre-intakes cold gas before discharging, which absorbs the heat generated during compression to ensure the thermal balance of the pump and keep the temperature of the rotor within a reasonable range, avoiding excessive expansion of the rotor.

[0004] The gas-cooled roots vacuum pump can be directly started under atmospheric pressure and work independently. It has a stable pumping speed curve at high pressure and can greatly shorten the pumping time in the roughing stage (low vacuum range). The gas-cooled roots vacuum pump can work normally under a high pressure difference of 8.7×104 Pa without overheating. When used alone and directly discharged to atmosphere, the gas-cooled roots vacuum pump can obtain an extreme pressure of about 1×104 Pa, and a lower extreme pressure can be obtained when used in series. The gas-cooled roots vacuum pump has the advantages of large pumping speed, large load capacity, short pumping time, and low power consumption, and is a mainstream product of large pumping speed direct discharge to atmosphere oil-free vacuum pump.

[0005] The gas-cooled roots vacuum pump usually uses three-lobed rotors. The rotor impeller and the pump body form pump cavity base volume one and pump cavity base volume two. When the rotor impeller operates, the pump cavity base volume is suddenly opened to both sides of the high-pressure cold gas. The high-pressure cold gas has a high speed and will mix with the low-pressure gas in the pump cavity base volume, causing a violent pressure pulsation and a large impact on the low-pressure gas, resulting in a large pneumatic noise. When the gas-cooled roots vacuum pump operates under a high pressure difference, the impact of the high-pressure cold gas on the low-pressure gas in the pump body base volume is greater, and the pneumatic noise generated is also greater.

[0006] Reducing noise improves the working environment, and has great significance to improve people's physical and mental health. How to reduce the noise of air-cooled roots vacuum pump, and improve the cooling effect of return cooling gas, is the problem that vacuum industry practitioners need to solve.

[0007] The return cooling gas injection connecting piece in the prior art is a circular flange pipeline connecting piece with equal diameters at both ends, which has a small contact area with the pump body, a small amount of cold gas input into the pump cavity, and a large aerodynamic noise to the pump cavity when inputting, and a poor cooling effect.

[0008] Therefore, the utility model hopes to put forward a brand-new air-cooled roots vacuum pump containing a pre-air flange to solve the defects in the prior art. Utility model content

[0009] Therefore, the utility model aims to solve the problems in the prior art, and proposes an air-cooled roots vacuum pump containing a pre-air flange, which comprises

[0010] The pump body of the air-cooled roots vacuum pump;

[0011] The return cooling gas pipeline; and

[0012] At least one pre-air flange is arranged between the pump body and the return cooling gas pipeline; the return cooling gas pipeline is used for injecting the return cooling gas into the pump body through the pre-air flange;

[0013] The pre-air flange comprises:

[0014] The rectangular connecting flange is a rectangular frame structure, and the middle part is provided with an opening; the return cooling gas flows into the pump body through the opening;

[0015] The connecting pipe is connected to the outer edge of the opening of the rectangular connecting flange at one end; the connecting pipe extends from inside to outside, and the connecting pipe has a flow channel space; the flow channel space is in communication with the opening; and the inner wall of the pipeline of the connecting pipe is a streamline gradually changing structure;

[0016] The circular connecting flange is connected to the end of the connecting pipe away from the rectangular connecting flange, and the circular connecting flange forms a circular opening; the circular opening, the flow channel space and the opening are in communication.

[0017] Further optimization of the technical scheme, the ratio of the opening flow area of the rectangular connecting flange to the circular opening flow area of the circular connecting flange at the other end is 2.

[0018] Further optimization of the technical scheme, the ratio of the opening flow area of the rectangular connecting flange to the circular opening flow area of the circular connecting flange is greater than or equal to 1.5.

[0019] Further optimize the technical scheme, the center of the rectangular connecting flange and the center of the circular connecting flange have a certain eccentric distance.

[0020] Further optimize the technical scheme, the eccentric distance is 30mm.

[0021] Further optimize the technical scheme, the connecting pipe is slightly conical in whole.

[0022] Further optimize the technical scheme, a rectangular interface is arranged on the lower part of each pump body, for configuring a pre-air flange; the rectangular connecting flange is connected with the rectangular interface through bolts.

[0023] Further optimize the technical scheme, the circular connecting flange of the pre-air flange is provided with a return cooling gas pipeline, and the circular connecting flange of the pre-air flange is connected with a circular flange interface of the return cooling gas pipeline through bolts.

[0024] Further optimize the technical scheme, a rectangular ring groove is arranged on the outer edge of the rectangular interface of the pump body, for configuring a rectangular ring, and the rectangular connecting flange forms a sealed structure with the pump body.

[0025] Further optimize the technical scheme, an O-shaped ring groove is arranged on the outer edge of the circular connecting flange connected with the return cooling gas pipeline, for configuring an O-shaped ring, and the circular connecting flange forms a sealed structure with the return cooling gas pipeline.

[0026] Compared with the prior art, the pre-air flange has the following advantages: through the special structural design of the pre-air flange, that is, the large space, streamline shape, eccentric arrangement and buffer principle, the return cooling gas storage capacity is large, the airflow is uniform, the return cooling gas enters the pump body after buffering through the pre-air flange, the pressure pulsation is reduced when the high-pressure return cooling gas is connected with the low-pressure gas in the pump body, thereby the noise of the air-cooled Roots vacuum pump in the working process is reduced, and the cooling effect is improved. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a front view of the pre-air flange of the utility model.

[0028] Figure 2 It is a rear view of the pre-air flange of the utility model.

[0029] Figure 3 It is a schematic view when the utility model is implemented.

[0030] Figure 4 It is a connection view of the pre-air flange of the utility model and the pump body.

[0031] Figure 5 It is a connection side view of the pre-air flange of the utility model and the pump body.

[0032] Figure 6A schematic diagram of the running state in use of the utility model.

[0033] In the figure: 1, pump body; 100, pre-intake flange; 11, return cold gas pipeline; 111, return cold gas; 12, rectangular interface; 2, rectangular ring; 21, rectangular ring groove; 22, O-ring; 23, O-ring groove; 3, rectangular connecting flange; 31, opening; 4, connecting pipe; 41, flow channel space; 5, circular connecting flange; 51, circular opening. DETAILED DESCRIPTION

[0034] The structure, effects and advantages of the utility model will be described in detail below with reference to the preferred embodiment of the utility model and the accompanying drawings.

[0035] As shown in Figures 1 to 6 , a gas-cooled roots vacuum pump with a pre-intake flange in the utility model is shown, as shown in Figure 6 , the pre-intake flange 100 is connected between the pump body 1 of the gas-cooled roots vacuum pump and the return cold gas pipeline 11. The return cold gas pipeline 11 is used to inject the return cold gas 111 into the pump body 1 through the pre-intake flange 100.

[0036] As shown in Figure 1 and Figure 2 , the pre-intake flange 100 includes a rectangular connecting flange 3,

[0037] The rectangular connecting flange 3 is a rectangular frame structure, and an opening 31 is formed in the middle part, so that the return cold gas 111 can flow into the pump body 1 through the opening 31.

[0038] It also includes a connecting pipe 4, one end of which is connected to the outer edge of the opening 31 of the rectangular connecting flange 3. The connecting pipe 4 extends from the inside to the outside, as shown in Figure 2 and Figure 5 , the connecting pipe 4 has a slightly conical structure as a whole. The connecting pipe 4 has a flow channel space 41, which is in communication with the opening 31. The inner wall of the connecting pipe 4 is curved, and the turning part is smoothly and naturally transitioned. This kind of streamline gradually changing structure reduces the air flow resistance, so that the return cold gas 111 injected into the pump body 1 flows more smoothly, the air flow impact is small, the aerodynamic noise is small, and the cooling effect is good.

[0039] A circular connecting flange 5 is connected to the other end of the connecting pipe 4, which forms a circular opening 51. The circular opening 51, the flow channel space 41 and the opening 31 are in communication, so the return cold gas 111 in the return cold gas pipeline 11 can flow through the connecting pipe 4 through the circular connecting flange 5 and enter the pump body 1 through the rectangular connecting flange 3.

[0040] Preferably, the total width of the pre-intake flange 100, that is, the distance from the bottom surface of the rectangular connecting flange 3 to the top surface of the circular connecting flange 5, is 140 mm, and the width of the connecting pipe 4 is 95 mm.

[0041] Preferably, a rectangular interface 12 is formed on the lower part of each side of the pump body 1, which is used to configure the pre-air flange 100. Please refer to Figure 4 The rectangular connecting flange 3 of the pre-air flange 100 is connected to the rectangular interface 12 of the pump body 1, which can maximize the flow area of the return cooling gas 111 and make the injection of the return cooling gas 111 uniform.

[0042] As shown in Figure 5 , the circular connecting flange 5 of the pre-air flange 100 is configured with a return cooling gas pipeline 11, and the circular connecting flange 5 of the pre-air flange 100 is connected to a circular flange interface (not shown in the figure) of the return cooling gas pipeline 11 through M10 bolts.

[0043] As shown in Figure 4 , a rectangular ring groove 21 corresponding to the rectangular interface 12 is formed on the outer edge of the rectangular interface 12 of the pump body 1, which is used to configure a rectangular ring 2, so that the rectangular connecting flange 3 and the pump body 1 form a sealed structure. The rectangular ring sealing has good sealing effect and is easy to install.

[0044] As shown in Figure 4 , the outer edge of the circular connecting flange 5 connecting the return cooling gas pipeline 11 forms an O-ring groove 23 corresponding to the circular flange interface, which is used to configure an O-ring 22, so that the circular connecting flange 5 and the return cooling gas pipeline 11 form a sealed structure. The O-ring sealing has good sealing effect and is easy to install.

[0045] The opening 31 of the rectangular connecting flange 3 has a flow area of 64125mm2, and the circular opening 51 of the circular connecting flange 5 at the other end has a flow area of 31400mm2, and the ratio of the flow areas of the two is 2, so that the flow rate of the return cooling gas 111 at the rectangular connecting flange 3 of the pre-air flange 100 is less than that at the circular connecting flange 5, which is beneficial to reduce the impact of high-pressure return cooling gas on the pump body 1 and improve the cooling effect. Preferably, the ratio of the flow area of the opening 31 of the rectangular connecting flange 3 to the flow area of the circular opening 51 of the circular connecting flange 5 is ≥1.5.

[0046] The center of the rectangular connecting flange 3 and the center of the circular connecting flange 5 have an eccentricity of 30mm, and the connecting pipe 4 is connected in the middle, so that the storage amount of the return cooling gas 111 in the pre-air flange cavity is maximized, the storage amount of the return cooling gas 111 is large, and the buffer rotation space is large, so that the gas flow impact is small, the aerodynamic noise is small, and the cooling effect is good. At the same time, it is beneficial to the deposition and dust removal of the return cooling gas 111, and the return cooling gas 111 is clean.

[0047] In summary, the humanized and considerate design of the utility model is quite in line with the actual demand.

[0048] The above detailed description is a specific description of a feasible embodiment of the utility model, and the described embodiment is not used to limit the patent range of the utility model, and equivalent implementation or changes without departing from the spirit of the utility model art should be included in the patent range of the utility model.

Claims

1. A gas-cooled Roots vacuum pump comprising a pre-inlet flange, characterized in that: Comprising Air-cooled Roots vacuum pump body (1); Return cooling gas pipeline (11) and At least one pre-bleed flange (100) is provided between the pump body (1) and the return cooling gas pipeline (11); the return cooling gas pipeline (11) is used to inject return cooling gas (111) into the pump body (1) through the pre-bleed flange (100); The pre-bleed flange (100) comprises: A rectangular connection flange (3) is a rectangular frame structure, and a central opening (31) is provided in the middle, and the return cooling gas (111) flows into the pump body (1) through the opening (31); A connecting pipe (4) is connected to the outer edge of the opening (31) of the rectangular connection flange (3); the connecting pipe (4) extends from inside to outside, and has a flow channel space (41) which is in communication with the opening (31); the inner wall of the connecting pipe (4) is a streamline gradually changing structure; A circular connection flange (5) is connected to the end of the connecting pipe (4) away from the rectangular connection flange (3), and the circular connection flange (5) forms a circular opening (51); the circular opening (51), the flow channel space (41) and the opening (31) are in communication.

2. The air-cooled Roots vacuum pump comprising a pre-bleed flange according to claim 1, wherein the ratio of the flow area of the opening (31) of the rectangular connection flange (3) to the flow area of the circular opening (51) of the circular connection flange (5) at the other end is 2.

3. The air-cooled Roots vacuum pump comprising a pre-bleed flange according to claim 1, wherein the ratio of the flow area of the opening (31) of the rectangular connection flange (3) to the flow area of the circular opening (51) of the circular connection flange (5) is greater than or equal to 1.

5.

4. The air-cooled Roots vacuum pump comprising a pre-bleed flange according to claim 1, wherein the center of the rectangular connection flange (3) is eccentric to the center of the circular connection flange (5) by a certain distance.

5. The air-cooled Roots vacuum pump comprising a pre-bleed flange according to claim 4, wherein the eccentric distance is 30 mm.

6. The air-cooled Roots vacuum pump comprising a pre-bleed flange according to claim 1, wherein the connecting pipe (4) is slightly conical in structure as a whole.

7. The air-cooled Roots vacuum pump comprising a pre-bleed flange according to claim 1, wherein a rectangular interface (12) is provided at the lower part of each side of the pump body (1) for arranging the pre-bleed flange (100); the rectangular connection flange (3) is connected to the rectangular interface (12) by bolts.

8. The air-cooled Roots vacuum pump comprising a pre-bleed flange according to claim 1, wherein the circular connection flange (5) of the pre-bleed flange (100) is arranged with the return cooling gas pipeline (11), and the circular connection flange (5) of the pre-bleed flange (100) is connected to a circular flange interface of the return cooling gas pipeline (11) by bolts.

9. A gas-cooled Roots vacuum pump comprising a pre-inlet flange according to claim 7; a rectangular ring groove (21) is arranged on the outer edge of the rectangular interface (12) of the pump body (1) for arranging a rectangular ring (2), and the rectangular connecting flange (3) and the pump body (1) form a sealed structure.

10. A gas-cooled Roots vacuum pump comprising a pre-inlet flange according to claim 1; an O-ring groove (23) is arranged on the outer edge of the circular connecting flange (5) connected with the cold return gas pipeline (11) for arranging an O-ring (22), and the circular connecting flange (5) and the cold return gas pipeline (11) form a sealed structure.

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