Diffusion pump

Abstract

The invention provides a diffusion pump which comprises a pump body, a backing pump connecting channel arranged on the wall of the pump body and an auxiliary piston cylinder. A piston capable of reciprocating along the axis direction of the auxiliary piston cylinder is arranged in the auxiliary piston cylinder; the auxiliary piston cylinder oil storage end comprises a space defined by the bottom of the auxiliary piston cylinder and the side wall, close to the bottom, of the auxiliary piston cylinder. A heating component is arranged adjacent to the oil storage end of the auxiliary piston cylinder; the oil injection channel is communicated with the oil storage end of the auxiliary piston cylinder and an oil injection pipe of the pump main body; and an overflow channel communicated with the pump main body and the auxiliary piston cylinder is arranged. The diffusion pump is short in starting and ending time and high in efficiency.

Description

Technical Field

[0001] The present invention relates to a vacuum pumping device, in particular to a vacuum diffusion pump. Background Art

[0002] The vacuum diffusion pump is one of the effective methods to obtain a vacuum. Its principle is to use low-pressure, high-speed and directed-flowing oil vapor to bring gas molecules into the low-pressure area, thereby achieving vacuum pumping. To enable the oil molecules to diffuse more effectively, it is necessary to heat the pump oil to reduce its viscosity and improve its fluidity. Subsequently, the oil molecules can be quickly and evenly distributed in the pump, improving the efficiency of vacuum pumping. The pump oil is heated by the bottom heating plate in the pump body of the diffusion pump, and the pump oil evaporates to form oil vapor.

[0003] It takes a certain amount of heating time for the pump oil to be heated from room temperature to the boiling temperature. There is a large temperature difference between the initially rising oil vapor and the pump core, causing a part of the pump oil to be adsorbed on the pump core and not reaching a stable working state. It takes a certain amount of time to continuously input oil vapor to raise the temperature in the space above the pump core to the temperature required for normal operation. It can be seen that the existing diffusion pump requires a long startup time to reach a stable working state and has low efficiency.

[0004] In addition, after the existing diffusion pump stops working, since the pump oil has been heated to the boiling temperature, it needs to be cooled down. After the temperature drops to a certain extent, other equipment connected to the diffusion pump can enter the next process. The cooling process of the existing diffusion pump mainly relies on the cooling device set locally in the diffusion pump. Due to the low local cooling efficiency, there is also the problem of a long cooling time for the diffusion pump. Summary of the Invention

[0005] In order to solve the problems of long startup time and long cooling time of the existing diffusion pump, resulting in low efficiency, the present invention provides a diffusion pump.

[0006] The technical solution of the present invention is as follows:

[0007] A diffusion pump includes a pump body, a fore-pump connection channel provided on the wall of the pump body, and an auxiliary piston cylinder is also provided; a piston that can reciprocate along the axial direction of the auxiliary piston cylinder is provided in the auxiliary piston cylinder; the oil storage end of the auxiliary piston cylinder includes the space surrounded by the bottom of the auxiliary piston cylinder and the side wall of the auxiliary piston cylinder adjacent to the bottom; an oil injection channel communicating the oil storage end of the auxiliary piston cylinder with the oil injection pipe of the pump body is provided; an overflow channel communicating the pump body with the auxiliary piston cylinder is provided.

[0008] Optionally, a cooling component and / or a heating component are provided adjacent to the oil storage end of the auxiliary piston cylinder of the diffusion pump.

[0009] Optionally, the auxiliary piston cylinder is partitioned by the piston into two cavities: a cavity including the oil storage end of the auxiliary piston cylinder and an air storage cavity; an air inlet and an air outlet are provided on the wall of the air storage cavity; the air outlet is communicated with the cooling component.

[0010] Optionally, an oil replenishing port is provided on the overflow passage.

[0011] Optionally, the diffusion pump is provided with an auxiliary oil tank communicated with the oil replenishing port; a driving mechanism is provided for driving one end of the auxiliary oil tank away from the oil replenishing port to lift.

[0012] Optionally, the distance between the outlet of the auxiliary piston cylinder and the bottom of the auxiliary piston cylinder at the oil storage end of the auxiliary piston cylinder in the overflow passage is a; the distance between the stroke stop point of the end face of the piston facing the oil storage end of the auxiliary piston cylinder away from the oil storage end of the auxiliary piston cylinder and the bottom of the auxiliary piston cylinder at the oil storage end of the auxiliary piston cylinder is b, and b is greater than or equal to a.

[0013] Optionally, the fore-pump connection passage communicates the pump body with the auxiliary piston cylinder; a piston rod is provided on the piston; a diversion and condensation component is provided on the piston rod; the diversion and condensation component and the inner wall of the auxiliary piston cylinder form a spiral rising passage.

[0014] Optionally, an oil injection port is provided at the top end of the pump core of the pump body facing the wall of the pump body; a pump core valve for switching the oil injection port is provided.

[0015] Optionally, the pump core valve includes a telescopic rod for driving the valve core; the telescopic rod is connected with a driving mechanism arranged outside the pump body.

[0016] Optionally, diversion teeth protruding between the vertical wall and the umbrella-shaped nozzle assembly are provided between the vertical wall of the pump core of the pump body and the umbrella-shaped nozzle assembly; the diversion teeth and the vertical wall and the umbrella-shaped nozzle assembly form an oil mist nozzle.

[0017] The technical effects of the present invention are as follows:

[0018] The diffusion pump of the present invention is provided with an auxiliary piston cylinder communicated with the pump body. During the start-up heating stage of the diffusion pump, the reciprocating movement of the piston can spray the gradually heated pump oil upward through the oil spray pipe of the pump body to the upper part of the pump core, so that the upper space of the pump core can also be heated by a large amount of pump oil synchronously, without waiting for the pump oil to generate oil vapor to heat the upper part of the pump core. At the same time, the pump oil in the pump body can flow back to the oil storage end of the auxiliary piston cylinder through the overflow passage during the heating stage, forming a circulating flow of the pump oil. The pump oil is also heated synchronously during the circulating flow process, thus improving the heating efficiency.

[0019] During the cooling stage of the diffusion pump, the reciprocating motion of the piston can transport the pump oil that is gradually cooled through the injection pipe of the pump body to the upper space of the pump core, enabling the upper space of the pump core to be cooled synchronously without waiting for the natural cooling of the upper space of the pump core, thus improving the cooling efficiency. Additionally, the pump oil transported to the upper space of the pump core is sprayed onto the inner wall of the pump body through the injection nozzle (or injection port) of the pump core, and the cooling medium flowing in the cooling surrounding pipe provided on the outer wall of the pump body can exchange heat with the pump oil sprayed onto the inner wall of the pump body, accelerating the cooling of the pump oil, thereby overall improving the efficiency of the cooling stage of the diffusion pump.

[0020] In summary, the technical solution of the present invention achieves the purpose of the present invention.

[0021] The further effects of the above optional methods will be described below in conjunction with specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a front view of the first embodiment of the present invention.

[0023] Figure 2 It is Figure 1 a perspective view of the illustrated embodiment.

[0024] Figure 3 It is Figure 1 a sectional view of the illustrated embodiment.

[0025] Figure 4 It is Figure 1 a sectional view of the bottom component of the illustrated embodiment.

[0026] Figure 5 It is Figure 1 a perspective view of the bottom component of the illustrated embodiment.

[0027] Figure 6 It is Figure 1 a perspective view of the bottom component of the illustrated embodiment.

[0028] Figure 7 It is Figure 6 a sectional view of the bottom component of the illustrated embodiment.

[0029] Figure 8 It is Figure 5 a view of the bottom component from another angle of the illustrated one.

[0030] Figure 9 It is a schematic diagram of the composition of the cooling component of the second embodiment of the present invention.

[0031] Figure 10 It is a sectional view of the third embodiment of the present invention.

[0032] Figure 11Cross-sectional view of the fourth embodiment of the present invention.

[0033] Figure 12 is Figure 11 a partially enlarged view of the illustrated embodiment.

[0034] The reference numerals in the figure are explained as follows:

[0035] 101, fore-pump connection passage; 102, auxiliary piston cylinder; 103, support pivot; 104, auxiliary oil tank; 105, driving cylinder; 106, pump body;

[0036] 201, oil injection pipe; 202, air pipe;

[0037] 301, fore-pump connection port; 302, piston rod; 303, diversion and condensation component; 304, piston; 305, cooling component; 306, heating component; 307, overflow passage; 308, oil injection passage; 309, oil injection pipe; 310, pump core;

[0038] 401, oil injection port; 402, coolant inlet;

[0039] 501, filter screen;

[0040] 801, cooling passage;

[0041] 901, gas storage cavity; 902, solenoid valve; 903, solenoid valve; 904, silencer;

[0042] 1001, oil injection nozzle; 1002, telescopic rod; 1003, cylinder;

[0043] 1101, umbrella-shaped nozzle assembly; 1102, vertical wall;

[0044] 1201, diversion teeth. Detailed implementation manners

[0045] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0046] Figures 1 to 8 shows the specific structure of the first embodiment of the present invention. As Figure 1 shown, the diffusion pump of the present invention includes a pump body 106 and a fore-pump connection passage 101 provided on the wall of the pump body 106. The interior of the pump body 106 includes the main structures of a conventional diffusion pump, such as a pump core 310 (refer to Figure 3) The bottom oil sump and the like. The fore-pump connection passage 101 is a passage for communicating with a fore-pump (not shown in the figure). The diffusion pump is further provided with an auxiliary piston cylinder 102. The fore-pump connection passage 101 communicates the pump body 106 with the auxiliary piston cylinder 102. In other embodiments, the fore-pump connection passage may communicate with the fore-pump in a conventional manner, and the auxiliary piston cylinder is independently provided and not communicated with the fore-pump connection passage.

[0047] As Figure 1 shown, an auxiliary oil tank 104 is provided around the pump body 106. The main body of the auxiliary oil tank 104 is a hollow ring-shaped body. One side of the auxiliary oil tank 104 ( Figure 1 the left side of the auxiliary oil tank 104 in the figure) is hinged to the auxiliary piston cylinder 102 through a support pivot 103; the other side of the auxiliary oil tank 104 ( Figure 1 the right side of the auxiliary oil tank 104 in the figure) is hinged to the telescopic push rod of the driving cylinder 105. As Figure 2 shown, on one side of the auxiliary oil tank 104 ( Figure 1 the left side of the auxiliary oil tank 104 in the figure) is provided with an oil injection pipe 201. Through the oil injection pipe 201, the auxiliary oil tank 104 can communicate with the internal space of the pump body 106. On the other side of the auxiliary oil tank 104 ( Figure 1 the right side of the auxiliary oil tank 104 in the figure) is provided with an air pipe 202. The air pipe 202 also communicates the auxiliary oil tank 104 with the internal space of the pump body 106 (the upper space of the pump oil liquid level inside the pump body 106). When the driving cylinder 105 drives to lift this side of the auxiliary oil tank 104, the pump oil stored inside the auxiliary oil tank 104 can be injected into the pump body 106 through the oil injection pipe 201. The air pipe 202 is used to balance the air pressure inside the pump body 106 and the auxiliary oil tank 104, so that the pump oil can be smoothly injected into the pump body 106.

[0048] Figure 3 The up and down direction in the figure is the direction of gravity. For the description of Figure 3 , unless otherwise specified, the terms "upper" and "lower" refer to the up and down in the direction of gravity. As Figure 3 shown, the axis of the internal space of the auxiliary piston cylinder 102 is parallel to the direction of gravity. The piston 304 provided inside the auxiliary piston cylinder 102 can reciprocate along the axis direction. The upper space of the auxiliary piston cylinder 102 communicates with the fore-pump through a fore-pump connection port 301. Above the piston 304 is provided with a piston rod 302, and a spiral-shaped flow guiding and condensing component 303 is provided on the piston rod 302. The flow guiding and condensing component 303 is a spiral sheet structure and forms a spiral rising channel with the inner wall of the auxiliary piston cylinder 102. When the gas from the fore-pump connection passage 101 passes through the rising channel, the oil mist in the gas can be condensed into liquid droplets. The liquid droplets flow downward along the rising channel under the action of gravity.

[0049] As Figure 3As shown, the lower end portion of the auxiliary piston cylinder 102, including the space enclosed by the bottom of the auxiliary piston cylinder 102 and the side wall of the auxiliary piston cylinder 102 adjacent to the bottom, is the oil storage end of the auxiliary piston cylinder, where the pumped oil can reside. A heating component 306 is provided adjacent to the oil storage end of the auxiliary piston cylinder (the bottom of the auxiliary piston cylinder 102). A cooling component 305 is also provided adjacent to the oil storage end of the auxiliary piston cylinder (the side wall of the auxiliary piston cylinder 102). The diffusion pump is further provided with an oil injection passage 308 connecting the oil storage end of the auxiliary piston cylinder and the oil injection pipe 309 within the pump main body 106. An overflow passage 307 connecting the pump main body 106 (specifically, the oil sump of the pump main body 106) and the oil storage end of the auxiliary piston cylinder is also provided above the oil injection passage 308. Within the pump main body 106, the oil injection pipe 309 and the pump core 310 are arranged in the same manner as in the prior art, and the nozzle of the oil injection pipe 309 faces the upper space of the pump core 301. A heating device and a cooling device are provided below the oil sump of the pump main body 106.

[0050] Figure 4 It further shows the specific structures of the oil sump portion of the pump main body 106 and the oil storage end portion of the auxiliary piston cylinder. An oil filling port 401 is also provided at the overflow passage 307. The oil filling port 401 is connected to an oil filling pipe 201. The cooling component 305 includes a cavity for containing a coolant, and a coolant inlet 402 is provided in this cavity.

[0051] Figure 5 and Figure 6 shows in a perspective view the Figure 4 structure of the portion shown. As Figure 5 and Figure 6 shown, a filter screen 501 is provided at the passage opening of the overflow passage 307 of the oil sump of the pump main body 106. The filter screen 501 is used to filter impurities in the pumped oil. As Figure 6 can be seen, multiple overflow passages 307 are provided.

[0052] Figure 7 shows in a sectional view the Figure 5 and Figure 6 internal structure of the portion shown.

[0053] Figure 8 shows the Figure 5 and Figure 6 structure of the back of the bottom of the oil sump where the oil injection pipe 309 is located. The curved arrangement of the oil injection passage 308 enables the pumped oil from the auxiliary piston cylinder 102 to gradually reach the position where the oil injection pipe 309 is located. The curved arrangement of the cooling passage 801 can achieve the effect of comprehensively cooling the bottom of the oil sump.

[0054] The following is a description of Figures 1 to 8The working process of the first embodiment of the present invention shown is described to further illustrate the technical solution of the present invention.

[0055] In the startup stage of the diffusion pump, the heating device below the oil sump of the pump body 106 starts to heat the pump oil in the oil sump. At the same time, the heating component 306 also starts to heat the pump oil in the oil storage end of the auxiliary piston cylinder. The piston 304 starts to reciprocate. Driven by the piston 304, the pump oil is sprayed into the upper space of the pump core 310 through the spray oil pipe 309. That is, while the pump oil is being heated at startup, it also uses its own heat energy to heat the upper space of the pump core 310. Compared with the existing diffusion pump, which needs to wait until the pump oil reaches the evaporation state and then uses the evaporated oil mist to heat the upper space of the pump core, the diffusion pump of the present invention can heat the upper space of the pump core 310 more efficiently, enabling the diffusion pump to reach the working temperature as soon as possible. At the same time, the additional heating component 306 also increases the power of heating the pump oil, which can further improve the startup efficiency of the diffusion pump. When there is too much pump oil in the oil sump of the pump body 106, the pump oil can flow back into the oil storage end of the auxiliary piston cylinder through the overflow channel 307 to form a circulating flow. When it is necessary to replenish the pump oil, the pump oil can be replenished through the oil filling port 401. When the diffusion pump reaches the working temperature and state, the piston 304 can stop reciprocating.

[0056] If the distance between the outlet of the auxiliary piston cylinder 102 of the overflow channel 307 and the bottom of the auxiliary piston cylinder 102 at the oil storage end of the auxiliary piston cylinder is a; the distance between the end face of the piston 304 facing the oil storage end of the auxiliary piston cylinder and the bottom of the auxiliary piston cylinder 102 at the oil storage end of the auxiliary piston cylinder when the piston 304 is away from the stroke stop point of the oil storage end of the auxiliary piston cylinder is b, and b is greater than or equal to a. That is, Figure 3 Taking the lower end face of the piston 304 as a mark, the upper limit of the stroke of the piston 304 is at or above the upper edge of the outlet of the auxiliary piston cylinder 102 of the overflow channel 307.

[0057] When the diffusion pump starts to stop working, cooling medium is injected into the cooling channel 801. Through the flow of the cooling medium, the oil sump of the pump body 106 is cooled. At the same time, the cooling component 305 starts to cool the auxiliary piston cylinder 102. The piston 304 starts to reciprocate, driving the cooled pump oil to be ejected through the injection pipe 309 to rapidly cool the upper space of the pump core 310. When there is too much pump oil in the oil sump of the pump body 106 of the pump oil, the pump oil can return to the oil storage end of the auxiliary piston cylinder through the overflow channel 307 to form a circulating flow. The additionally provided cooling component 305 can introduce more cooling medium, improving the cooling efficiency. In addition, the pump oil delivered to the upper space of the pump core 310 is ejected onto the inner wall of the pump body 106 through the injection nozzle (or injection port) of the pump core 310. The cooling medium flowing in the cooling surrounding pipe provided on the outer wall of the pump body 106 can exchange heat with the pump oil ejected onto the inner wall of the pump body 106, accelerating the cooling of the pump oil, thereby overall improving the efficiency of the cooling stage of the diffusion pump. That is, in the cooling stage, the cooling device on the outer wall of the pump body 106 can directly cool the pump oil, further improving the cooling efficiency. In summary, the diffusion pump of the present invention can achieve rapid cooling when it stops working.

[0058] Figure 9 The illustrated embodiment illustrates the working mechanism of the cooling component of the auxiliary piston cylinder of the present invention. Figure 9 In Figures 1 to 8 The structure of the illustrated embodiment is described.

[0059] The auxiliary piston cylinder 102 is divided into two cavities by the piston 304: the cavity including the oil storage end of the auxiliary piston cylinder and the gas storage cavity 901. Two air ports, A and B, are provided on the wall of the gas storage cavity 901. Both A and B are connected to the electromagnetic valve 902. The electromagnetic valve 902 includes 4 ports: A1, B1, T1, and P. The electromagnetic valve 903 includes 4 ports: A2, B2, T2, and T3. When the diffusion pump starts, the gas flow direction is: external air enters through P and flows through P - A1 - A - B - B1 - T1 - B2 - T2 (atmosphere). When the diffusion pump starts to stop working, the gas flow direction is: external air enters through P and flows through P - A1 - A - B - B1 - T1 - B2 - T3 - coolant inlet 402 - cooling component 305 - silencer 904. It can be seen that when the diffusion pump starts to stop working, the piston 304 drives air as the cooling medium to be cooled at the cooling component 305.

[0060] Figure 10 The third embodiment of the present invention shown and Figure 1The difference of the first embodiment shown is that an oil injection port 1001 is provided at the top of the pump core, and a pump core valve matching the oil injection port 1001. The oil injection port 1001 is arranged facing the wall of the pump body. The pump core valve includes a telescopic rod 1002. The telescopic rod 1002 performs a telescopic movement under the drive of the cylinder 1003, so as to open or close the oil injection port 1001. When the diffusion pump starts to stop working, the pump core valve opens, and the pump oil ejected from the oil injection pipe below in the pump body can be sprayed onto the wall of the pump body through the oil injection port 1001, and the wall of the pump body can be used to accelerate the cooling of the pump oil, thereby further improving the cooling efficiency when the diffusion pump starts to stop working.

[0061] Figure 11 and Figure 12 shows the fourth embodiment of the present invention. As Figure 11 and Figure 12 shown, the main difference between this embodiment and the embodiment shown in Figure 1 is that a number of raised flow guiding teeth 1201 are provided between the vertical wall 1102 of the pump core in the pump body and the umbrella-shaped nozzle assembly 1101 buckled on the vertical wall 1102. In this embodiment, the flow guiding teeth 1201 are helical teeth. The raised flow guiding teeth 1201 form an oil mist nozzle between the vertical wall 1102 and the umbrella-shaped nozzle assembly 1101. The above setting plays a guiding role in the diffusion of the oil mist, promoting the more uniform distribution of the oil mist. In addition, the existing oil mist nozzle is formed by supporting the umbrella-shaped nozzle assembly with raised screws on the vertical wall, but the installation accuracy of the screws is not high, resulting in inconsistent sizes of the circumferentially distributed oil mist nozzles, and thus uneven oil mist distribution. The flow guiding teeth 1201 of this embodiment can obtain higher accuracy through machining, avoiding the problem of low accuracy of manual operation.

[0062] It should be noted that the above are only the preferred embodiments of the present invention, and do not limit the patent protection scope of the present invention accordingly. The present invention can also be replaced by equivalent technologies. Therefore, all equivalent changes made by using the description and illustrations of the present invention, or directly or indirectly applied to other related technical fields are included in the scope covered by the present invention.

Claims

1. A diffusion pump, comprising a pump body, a front pump connecting channel arranged on the wall of the pump body, characterized in that: An auxiliary piston cylinder is also provided; a piston which can reciprocate along the axial direction of the auxiliary piston cylinder is provided in the auxiliary piston cylinder; an oil storage end of the auxiliary piston cylinder includes a space enclosed by the bottom of the auxiliary piston cylinder and the side wall of the auxiliary piston cylinder adjacent to the bottom; an oil injection channel of an oil injection pipe connecting the oil storage end of the auxiliary piston cylinder and the pump body is provided; an overflow channel connecting the pump body and the auxiliary piston cylinder is provided.

2. A diffusion pump according to claim 1, characterized in that: A cooling component and / or a heating component is arranged adjacent to the oil storage end of the auxiliary piston cylinder.

3. A diffusion pump according to claim 2, characterized in that: The auxiliary piston cylinder is divided into two cavities by the piston: a cavity at the oil storage end of the auxiliary piston cylinder and an air storage cavity; an air inlet and an air outlet are arranged on the wall of the air storage cavity; and the air outlet is connected to the cooling component.

4. A diffusion pump according to claim 1, characterized in that: An oil replenishing port is arranged on the overflow channel.

5. A diffusion pump according to claim 4, characterized in that: An auxiliary oil tank is provided which is communicated with the oil replenishing port; and a driving mechanism is provided which drives the end of the auxiliary oil tank which is away from the oil replenishing port to rise and fall.

6. A diffusion pump according to claim 1, characterized in that: The distance between the outlet of the overflow channel and the bottom of the auxiliary piston cylinder at the oil storage end of the auxiliary piston cylinder is a; the distance between the end face of the piston facing the oil storage end of the auxiliary piston cylinder, which is away from the oil storage end of the auxiliary piston cylinder, and the bottom of the auxiliary piston cylinder at the oil storage end of the auxiliary piston cylinder is b, and b is greater than or equal to a.

7. A diffusion pump according to claim 1, characterized in that: The front pump connecting channel connects the pump body and the auxiliary piston cylinder; a piston rod is arranged on the piston; a flow guiding and condensing component is arranged on the piston rod; the flow guiding and condensing component and the inner wall of the auxiliary piston cylinder form a spiral ascending channel.

8. A diffusion pump according to claim 1, characterized in that: An oil injection port facing the wall of the pump body is arranged at the top end of the pump core of the pump body; and a pump core valve for opening and closing the oil injection port is arranged.

9. A diffusion pump according to claim 8, characterized in that: The pump core valve comprises a telescopic rod for driving the valve core; the telescopic rod is connected to a driving mechanism arranged outside the pump body.

10. A diffusion pump according to claim 1, characterized in that: A guide tooth protruding between the vertical wall of the pump core of the pump body and the umbrella-shaped nozzle assembly is arranged between the vertical wall and the umbrella-shaped nozzle assembly; the guide tooth, the vertical wall and the umbrella-shaped nozzle assembly form an oil mist nozzle.

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