Automatic pressure-stabilizing molecular pump and control method thereof

Abstract

The present invention relates to the technical field of vacuum pumps, and discloses an automatic pressure-stabilizing molecular pump and a control method thereof. The automatic pressure-stabilizing molecular pump comprises: a motor, a first electromagnetic valve group, a vacuum gauge, a control system, a multi-stage forward turbine, and a multi-stage reverse turbine, wherein the multi-stage forward turbine and the multi-stage reverse turbine are directly connected to the motor of the automatic pressure-stabilizing molecular pump; the first electromagnetic valve group is connected to the gas path leading out of each stage of the flow port; the vacuum gauge is connected to the control system; the control system is also connected to the first electromagnetic valve group, and the control system controls the switch state of the first electromagnetic valve group according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge, and short-circuits different turbine stages, thereby adjusting the compression ratio. The present invention designs a molecular pump reverse turbine, uses the reverse turbine to actively reduce the compression ratio, opens a flow port on the sealed housing of each stage of the turbine, and uses an electromagnetic valve to connect different turbine vacuum stages to achieve different compression ratios, thereby adjusting the vacuum pressure to the required pressure.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum pumps, and in particular to an automatic pressure-stabilizing molecular pump and a control method thereof. Background Art

[0002] The application of vacuum relies on vacuum pumps to obtain vacuum. There are two types of vacuum pumps: capture vacuum pumps and compression vacuum pumps. Compression vacuum pumps include molecular pumps. A molecular pump is a vacuum pump that uses a high-speed rotating rotor to transfer momentum to gas molecules, so that they can obtain a directional speed, and then be compressed and driven to the exhaust port to be pumped away by the front stage. The molecular pump itself is directly driven by a high-speed electric motor. Its pumping performance or compression ratio can be adjusted by adjusting the motor speed, but the speed adjustment response of the high-speed motor is relatively slow, and it takes a long time to increase or decrease the speed. In many vacuum applications, especially when adding various process reagents or process gases to the vacuum system, a faster response speed is often required to quickly adjust the compression ratio to achieve a stable air pressure. However, it is too late to adjust the compression ratio by adjusting the speed of the molecular pump. Summary of the invention

[0003] In view of this, the present invention provides an automatic pressure-stabilizing molecular pump and a control method thereof to solve the problem of slow time efficiency in adjusting the compression ratio by adjusting the motor speed.

[0004] In a first aspect, the present invention provides an automatic pressure-stabilizing molecular pump, wherein a flow port is opened on the sealed housing of each stage of the turbine of the automatic pressure-stabilizing molecular pump, and the automatic pressure-stabilizing molecular pump comprises: a motor, a first solenoid valve group, a vacuum gauge, a control system, a multi-stage forward turbine, and a multi-stage reverse turbine, wherein:

[0005] The multi-stage forward turbine and the multi-stage reverse turbine are directly connected to the motor of the automatic pressure-stabilizing molecular pump, the forward turbine is used for forward air extraction, and the reverse turbine is used for reverse air extraction;

[0006] The first solenoid valve group is connected to the gas path leading out of each level of flow outlet;

[0007] The vacuum gauge is connected to the control system, and is used to detect the pressure value at the pump port of the automatic pressure-stabilizing molecular pump and send the pressure value to the control system;

[0008] The control system is also connected to the first solenoid valve group. The control system controls the switch state of the first solenoid valve group according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge, short-circuit different turbine stages, and thus adjust the compression ratio.

[0009] In an optional embodiment, the automatic pressure-stabilizing molecular pump further includes: a second solenoid valve group, wherein the second solenoid valve group is connected to the gas path leading out of each stage of the flow outlet through a micropore.

[0010] In an optional embodiment, the first solenoid valve group includes a plurality of first solenoid valves, the first solenoid valves are arranged in one-to-one correspondence with the turbines, and each of the first solenoid valves is connected to the flow port of its corresponding turbine and the air path leading out of the flow port of an adjacent turbine.

[0011] In an optional embodiment, the second solenoid valve group includes a plurality of second solenoid valves, and the second solenoid valves are arranged in a one-to-one correspondence with the turbines, and each of the second solenoid valves is connected to the flow port of its corresponding turbine and the air path leading out of the flow port of the adjacent turbine through a micropore.

[0012] In an optional embodiment, the control system is also connected to the motor, and the control system also controls the rotation speed of the motor according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge.

[0013] In a second aspect, the present invention provides a control method for an automatic pressure-stabilizing molecular pump. Based on the automatic pressure-stabilizing molecular pump described in the first aspect, the control method comprises:

[0014] Obtaining target vacuum pressure;

[0015] Setting the speed of the automatic pressure-stabilizing molecular pump according to the target vacuum pressure;

[0016] Read the pressure value detected by the vacuum gauge;

[0017] The switch state of the first solenoid valve group is controlled according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge.

[0018] In an optional embodiment, setting the rotation speed of the automatic pressure-stabilizing molecular pump according to the target vacuum pressure includes:

[0019] Determining a vacuum level of the target vacuum pressure, the vacuum level includes a first vacuum segment and a second vacuum segment, the first vacuum segment has a lower level than the second vacuum segment, and the sum of the first vacuum segment and the second vacuum segment is equal to the vacuum pressure range;

[0020] When the target vacuum pressure belongs to the first vacuum section, the rotation speed of the automatic pressure-stabilizing molecular pump is set to a first rotation speed;

[0021] When the target vacuum pressure belongs to the second vacuum segment, the rotation speed of the automatic pressure-stabilizing molecular pump is set to the second rotation speed.

[0022] In an optional implementation, controlling the switch state of the first solenoid valve group according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge includes:

[0023] When the pressure value is less than the target vacuum pressure, closing the preset solenoid valve in the first solenoid valve group;

[0024] When the pressure value is greater than the target vacuum pressure, the preset solenoid valve in the first solenoid valve group is opened.

[0025] In an optional implementation, when the pressure value is greater than the target vacuum pressure, opening the preset solenoid valve in the first solenoid valve group includes:

[0026] Opening a preset solenoid valve in the second solenoid valve group;

[0027] It is determined whether the pressure value is better than the target vacuum pressure, and when the pressure value is better than the target vacuum pressure, a preset solenoid valve in the first solenoid valve group is opened.

[0028] In an optional implementation, it is determined whether the pressure value is better than the target vacuum pressure. When the pressure value is better than the target vacuum pressure, the rotation speed of the automatic pressure-stabilizing molecular pump and the switching states of the first solenoid valve group and the second solenoid valve group are adjusted.

[0029] The present invention provides an automatic pressure-stabilizing molecular pump, wherein a flow port is opened on the sealed housing of each stage of the turbine of the automatic pressure-stabilizing molecular pump, and the automatic pressure-stabilizing molecular pump comprises: a motor, a first electromagnetic valve group, a vacuum gauge, a control system, a multi-stage forward turbine, and a multi-stage reverse turbine, wherein the multi-stage forward turbine and the multi-stage reverse turbine are directly connected to the motor of the automatic pressure-stabilizing molecular pump, the forward turbine is used for forward exhaust, and the reverse turbine is used for reverse exhaust; the first electromagnetic valve group is connected to the air path led out of each stage of the flow port; the vacuum gauge is connected to the control system, and the vacuum gauge is used to detect the pressure value of the pump port of the automatic pressure-stabilizing molecular pump and send the pressure value to the control system; the control system is also connected to the first electromagnetic valve group, and the control system controls the switch state of the first electromagnetic valve group according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge, and short-circuits different turbine stages, thereby adjusting the compression ratio. The present invention designs a molecular pump reverse turbine, uses the reverse turbine to actively reduce the compression ratio, and opens a flow port on the sealed housing of each stage of the turbine, adopts an electromagnetic valve to connect different turbine vacuum stages, and connects different flow ports by switching the electromagnetic valve to achieve different compression ratios, thereby adjusting the vacuum pressure to the required pressure.

[0030] The present invention provides a control method for an automatic pressure-stabilizing molecular pump, the control method comprising: obtaining a target vacuum pressure; setting a rotation speed of the automatic pressure-stabilizing molecular pump according to the target vacuum pressure; reading a pressure value detected by a vacuum gauge; and controlling a switch state of a first electromagnetic valve group according to a difference between the target vacuum pressure and the pressure value detected by the vacuum gauge. By controlling the switch state of the first electromagnetic valve group to change the compression ratio of the molecular pump, the response speed is fast, and the target air pressure to be controlled can be automatically adjusted. By applying the technology of the present invention, the complexity of the vacuum system for users to achieve the same goal is greatly reduced, and the waste of reagents and gases caused by adjusting the air pressure can also be reduced, thereby comprehensively reducing the cost of vacuum application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 is a principle block diagram of an automatic pressure-stabilizing molecular pump according to an embodiment of the present invention;

[0033] Figure 2 is a structural schematic diagram of an automatic pressure-stabilizing molecular pump according to an embodiment of the present invention;

[0034] Figure 3 4 is a flow chart of a control method of an automatic pressure-stabilizing molecular pump according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0036] 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 a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] The present invention provides an automatic pressure-stabilizing molecular pump, wherein a flow port is opened on the sealed housing of each stage of the turbine of the automatic pressure-stabilizing molecular pump, such as Figure 1 As shown, the automatic pressure-stabilizing molecular pump includes: a motor, a first solenoid valve group, a vacuum gauge, a control system, a multi-stage forward turbine, and a multi-stage reverse turbine. Among them, the multi-stage forward turbine and the multi-stage reverse turbine are directly connected to the motor of the automatic pressure-stabilizing molecular pump, the forward turbine is used for forward pumping, and the reverse turbine is used for reverse pumping. The first solenoid valve group is connected to the air path leading out of each stage of the flow port. The vacuum gauge is connected to the control system, and the vacuum gauge is used to detect the pressure value of the pump port of the automatic pressure-stabilizing molecular pump and send the pressure value to the control system. The control system is also connected to the first solenoid valve group. The control system controls the switch state of the first solenoid valve group according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge, short-circuits different turbine stages, and thus adjusts the compression ratio.

[0039] In a specific embodiment, the speed of the motor of the automatic voltage-stabilizing molecular pump is unidirectional, but the turbine is designed as a forward and reverse turbine, and the number of stages of the forward turbine and the reverse turbine is designed according to the project requirements. And both the forward and reverse turbines are equipped with corresponding molecular pump stators. Both the forward turbine and the reverse turbine are directly connected to the molecular pump motor. The pumping direction of the forward turbine is from the air inlet to the air outlet, achieving forward pumping performance and thus achieving vacuum. The pumping direction of the reverse turbine is from the air outlet to the air inlet, and reverse pumping offsets the forward turbine. Each stage of the automatic voltage-stabilizing molecular pump is connected to the first solenoid valve group. By opening different solenoid valves in the first solenoid valve group and short-circuiting different turbine stages, the selected turbine stage can be activated or inactivated, thereby achieving the effect of adjusting the compression ratio. The vacuum gauge tests the pressure value of the pump port and sends the pressure value to the control system. The control system controls the speed of the pump and the opening and closing of the solenoid valve to achieve accurate and effective control so that the pump port pressure is close to the target vacuum pressure. Figure 2 The figure shows a typical design of an automatic pressure-stabilizing molecular pump.

[0040] In the embodiment of the present invention, the forward and reverse turbines are installed on the same main shaft and directly connected to the molecular pump motor, and the structure is simple and reliable. In other embodiments, in addition to designing the forward and reverse turbines, the automatic pressure-stabilizing molecular pump can also design a multi-stage forward turbine, and different pumping performances can be achieved by designing different forward turbine stages.

[0041] The present invention provides an automatic pressure-stabilizing molecular pump, wherein a flow port is opened on the sealed housing of each stage of the turbine of the automatic pressure-stabilizing molecular pump, and the automatic pressure-stabilizing molecular pump comprises: a motor, a first electromagnetic valve group, a vacuum gauge, a control system, a multi-stage forward turbine, and a multi-stage reverse turbine, wherein the multi-stage forward turbine and the multi-stage reverse turbine are directly connected to the motor of the automatic pressure-stabilizing molecular pump, the forward turbine is used for forward exhaust, and the reverse turbine is used for reverse exhaust; the first electromagnetic valve group is connected to the air path led out of each stage of the flow port; the vacuum gauge is connected to the control system, and the vacuum gauge is used to detect the pressure value of the pump port of the automatic pressure-stabilizing molecular pump and send the pressure value to the control system; the control system is also connected to the first electromagnetic valve group, and the control system controls the switch state of the first electromagnetic valve group according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge, and short-circuits different turbine stages, thereby adjusting the compression ratio. The present invention designs a molecular pump reverse turbine, uses the reverse turbine to actively reduce the compression ratio, and opens a flow port on the sealed housing of each stage of the turbine, adopts an electromagnetic valve to connect different turbine vacuum stages, and connects different flow ports by switching the electromagnetic valve to achieve different compression ratios, thereby adjusting the vacuum pressure to the required pressure.

[0042] In an optional embodiment, if Figure 2 As shown, the first solenoid valve group includes a plurality of first solenoid valves, and the first solenoid valves are arranged in one-to-one correspondence with the turbines, and each first solenoid valve is connected to the flow port of its corresponding turbine and the air path leading out of the flow port of the adjacent turbine.

[0043] In a specific embodiment, each stage of the flow port is connected to a solenoid valve, and by opening different solenoid valves and short-circuiting different turbine stages, the selected turbine stage is disabled, thereby achieving the effect of adjusting the compression ratio. For example, when the first solenoid valve corresponding to the -1 group of negative turbines is opened, the 1 group of negative turbines is short-circuited, reducing the offsetting effect of the negative turbines, thereby increasing the compression ratio. When the first solenoid valve corresponding to the -1 group of negative turbines is disconnected, the 1 group of negative turbines is added, increasing the offsetting effect of the negative turbines, thereby actively reducing the compression ratio by using the reverse turbine. When the first solenoid valve corresponding to the +2 group of positive turbines is opened, the 1 group of positive turbines is short-circuited, reducing the number of turbine stages of the automatic pressure-stabilizing molecular pump, thereby reducing the compression ratio. When the first solenoid valve corresponding to the +2 group of positive turbines is disconnected, the 1 group of positive turbines is added, increasing the number of turbine stages of the automatic pressure-stabilizing molecular pump, thereby increasing the compression ratio.

[0044] The present invention adopts multiple first solenoid valves to achieve rapid gas circuit switching. By connecting different gas circuits, different air pumping levels can be controlled to make different air pumping levels effective or ineffective. The control speed of the solenoid valve is relatively fast, so a faster control response speed can be achieved.

[0045] In an optional embodiment, if Figure 2 As shown, the automatic pressure-stabilizing molecular pump further includes: a second electromagnetic valve group, which is connected to the gas path leading out of each level of flow outlet through micropores.

[0046] In a specific embodiment, the second solenoid valve group includes a plurality of second solenoid valves, which are arranged one by one with the turbines, and each second solenoid valve is connected to the flow port of its corresponding turbine and the air path leading out of the flow port of the adjacent turbine through a micropore.

[0047] Specifically, the gas circuit connected to the second solenoid valve can be designed with micropores, and different micropores can achieve different vacuum conductances, so that the response speed can be adjusted to meet different needs. For example, when the first solenoid valve corresponding to the -1 group of negative turbines is opened, the offsetting effect of the negative turbines is reduced due to the short-circuiting of the group of negative turbines, but when the offsetting effect of the partial negative turbines is needed, the second solenoid valve corresponding to the group of negative turbines is closed, so that part of the gas passes through the group of negative turbines, thereby playing a partial offsetting role of the negative turbines. The gas circuit connected to the second solenoid valve in the present invention can be designed with micropores, and different micropores can achieve different vacuum conductances, so that the response speed can be adjusted to meet different needs.

[0048] In an optional implementation, the control system is also connected to the motor, and the control system also controls the rotation speed of the motor according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge.

[0049] In a specific embodiment, the automatic pressure-stabilizing molecular pump combines motor speed regulation with solenoid valve gas path switching to achieve a larger vacuum pressure adjustment range.

[0050] The present invention provides a control method for an automatic pressure-stabilizing molecular pump. Figure 2 The automatic pressure-stabilizing molecular pump shown in Figure 3 As shown, the control method includes the following steps:

[0051] Step S11, obtaining the target vacuum pressure.

[0052] In a specific embodiment, in the initial state, the setting values ​​of each system of the automatic pressure-stabilizing molecular pump are initialized, and the target vacuum pressure to be controlled is input, and the pressure range is 1*10^-1Pa to 1*10^-6Pa.

[0053] Step S12, setting the rotation speed of the automatic pressure-stabilizing molecular pump according to the target vacuum pressure.

[0054] In a specific embodiment, the pump speed gear is calculated according to the target vacuum pressure, and the pump speed is set according to the gear, wherein each gear setting ranges from 40% speed to 100% speed.

[0055] In the embodiment of the present invention, step S12 includes the following steps:

[0056] Step S121, determining the vacuum level of the target vacuum pressure, the vacuum level includes a first vacuum segment and a second vacuum segment, the first vacuum segment level is lower than the second vacuum segment, and the sum of the first vacuum segment and the second vacuum segment is equal to the vacuum pressure range.

[0057] Step S122, when the target vacuum pressure belongs to the first vacuum segment, the rotation speed of the automatic pressure-stabilizing molecular pump is set to the first rotation speed.

[0058] Step S123, when the target vacuum pressure belongs to the second vacuum segment, the rotation speed of the automatic pressure-stabilizing molecular pump is set to the second rotation speed.

[0059] Specifically, when the target vacuum pressure is at the low vacuum end of the molecular pump pressure range, that is, when the target vacuum pressure belongs to the first vacuum segment, the speed is set to low speed, and the specific speed value is set according to the project. When the set pressure is at the high vacuum end of the molecular pump pressure range, that is, when the target vacuum pressure belongs to the second vacuum segment, the speed is set to high speed or full speed, and the specific speed value is set according to the project. The boundary value between the first vacuum segment and the second vacuum segment is set according to the project.

[0060] Step S13, reading the pressure value detected by the vacuum gauge.

[0061] In a specific embodiment, after the rotation speed of the pump is set, the pump starts to work and the pressure value detected by the vacuum gauge is read.

[0062] Step S14, controlling the switch state of the first solenoid valve group according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge.

[0063] In a specific embodiment, step S14 includes the following steps:

[0064] Step S141, when the pressure value is less than the target vacuum pressure, closing the preset solenoid valve in the first solenoid valve group.

[0065] In the embodiment of the present invention, the solenoid valve to be closed in the first solenoid valve group is determined according to the gear position of the difference between the pressure value and the target vacuum pressure. When the difference is small, a small number of first solenoid valves can be closed, and a small number of turbine stages can be invested. The specific number and location of investment are set according to the project. When the difference is large, the number of first solenoid valves closed is increased, and the number of turbine stages invested is increased. The specific number and location of investment are set according to the project.

[0066] Step S142: when the pressure value is greater than the target vacuum pressure, the preset solenoid valve in the first solenoid valve group is opened.

[0067] In the embodiment of the present invention, when the pressure value is better than the target vacuum pressure, the preset solenoid valve in the second solenoid valve group is first opened. After the second solenoid valve group is regulated, it is judged again whether the pressure value is better than the target vacuum pressure. When the pressure value is better than the target vacuum pressure, the preset solenoid valve in the first solenoid valve group is opened. After the first solenoid valve group is regulated, it is judged again whether the pressure value is better than the target vacuum pressure. When the pressure value is better than the target vacuum pressure, the speed of the automatic pressure-stabilizing molecular pump and the switch states of the first solenoid valve group and the second solenoid valve group are adjusted.

[0068] Specifically, when the pressure value is better than the target vacuum pressure, the second solenoid valve of the vacuum micropore is opened first. If the vacuum degree is still too good and the target vacuum pressure cannot be reached, the first solenoid valve of the direct gas path is opened. If all the solenoid valves are opened and still cannot reach the target vacuum pressure, the first solenoid valve group and the second solenoid valve group are closed and the speed gear of the molecular pump is adjusted. After the speed is adjusted, the switch state of the first solenoid valve group and the second solenoid valve group is controlled again until the target vacuum pressure is reached. Among them, the number and position of the first solenoid valve and the second solenoid valve are set according to the project.

[0069] The present invention provides a control method for an automatic pressure-stabilizing molecular pump, the control method comprising: obtaining a target vacuum pressure; setting a rotation speed of the automatic pressure-stabilizing molecular pump according to the target vacuum pressure; reading a pressure value detected by a vacuum gauge; and controlling a switch state of a first electromagnetic valve group according to a difference between the target vacuum pressure and the pressure value detected by the vacuum gauge. By controlling the switch state of the first electromagnetic valve group to change the compression ratio of the molecular pump, the response speed is fast, and the target air pressure to be controlled can be automatically adjusted. By applying the technology of the present invention, the complexity of the vacuum system for users to achieve the same goal is greatly reduced, and the waste of reagents and gases caused by adjusting the air pressure can also be reduced, thereby comprehensively reducing the cost of vacuum application.

[0070] In a specific implementation example, the controllable vacuum pressure range is 1*10^-1Pa~1*10^-4Pa. The user sets three sections according to the process requirements: first, vacuum the pressure to 2*10^-3Pa, then the working pressure needs to be switched to 5*10^-2Pa during the process, and then vacuum the pressure again to 2*10^-3Pa after the process is completed. The specific control process is as follows:

[0071] Step 1, according to the high vacuum of the first stage setting value, the pump speed gear is calculated as a high speed gear;

[0072] Step 2. After the pump starts working, the vacuum gauge also starts to measure the actual vacuum degree. If the vacuum degree is worse than the set vacuum, the solenoid valve is closed to achieve the maximum pumping speed. If the vacuum degree is better than the set vacuum, the solenoid valve is opened to reduce the vacuum. First, open the solenoid valve of the vacuum micropore. If the vacuum degree is still too good and cannot reach the set value, open the solenoid valve of the direct gas path. If all the solenoid valves are opened and still cannot reach the set value, close the solenoid valve and adjust the speed gear of the molecular pump. After the speed is adjusted, control each solenoid valve again until the set value of 2*10^-3Pa in this example is achieved, completing the first stage of setting the target vacuum value.

[0073] Step 3. When the user issues the command for the second-stage set value of 5*10^-2Pa, the process gas may also be flowing into the vacuum chamber at this time, and the air pressure is changing. The molecular pump compares the real-time vacuum degree measured by the vacuum gauge with the set value. If the vacuum degree is worse than the set vacuum, the solenoid valve is closed to achieve the maximum pumping speed. If the vacuum degree is better than the set vacuum, the solenoid valve is opened to reduce the vacuum. First, open the solenoid valve of the vacuum micropore. If the vacuum degree is still too good and cannot reach the set value, open the solenoid valve of the direct gas path. If all the solenoid valves are opened and still cannot reach the set value, close the solenoid valve and adjust the speed gear of the molecular pump. After the speed is adjusted, control each solenoid valve again until the set value of 5*10^-2Pa in this example is achieved, completing the second stage of setting the target vacuum value.

[0074] Step 4. When the user process is completed, the set value of the third section, 2*10^-3Pa, is issued. The vacuum gauge also measures the real-time vacuum. If the vacuum is worse than the set vacuum, the solenoid valve is closed to achieve the maximum pumping speed. If the vacuum is better than the set vacuum, the solenoid valve is opened to reduce the vacuum. First, open the solenoid valve of the vacuum micropore. If the vacuum is still too good and cannot reach the set value, open the solenoid valve of the direct air path. If all the solenoid valves are opened and still cannot reach the set value, close the solenoid valve and adjust the speed gear of the molecular pump. After the speed is adjusted, control each solenoid valve again until the set value of 2*10^-3Pa in this example is achieved, completing the third section of setting the target vacuum value.

[0075] In a specific implementation example, when the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge is less than a certain fixed value, it is considered that the set pressure has been reached. If the difference is too large, the gear of the difference will be calculated, a judgment will be made and the difference will be set as the pump speed, and the pump speed and the switching state of the first solenoid valve group and the second solenoid valve group will be re-controlled to reach the target vacuum pressure. If the target vacuum pressure is still not reached after multiple cycles of adjustment, the closest maximum gear or minimum gear will be calculated, adjusted to this closest gear and displayed as the set pressure cannot be reached.

[0076] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An automatic pressure-stabilizing molecular pump, characterized in that: The sealed housing of each stage of the turbine of the automatic pressure-stabilizing molecular pump is provided with a flow port, and the automatic pressure-stabilizing molecular pump comprises: a motor, a first solenoid valve group, a vacuum gauge, a control system, a multi-stage forward turbine, and a multi-stage reverse turbine, wherein: The multi-stage forward turbine and the multi-stage reverse turbine are directly connected to the motor of the automatic pressure-stabilizing molecular pump, the forward turbine is used for forward air extraction, and the reverse turbine is used for reverse air extraction; The first solenoid valve group is connected to the gas path leading out of each level of flow outlet; The vacuum gauge is connected to the control system, and is used to detect the pressure value at the pump port of the automatic pressure-stabilizing molecular pump and send the pressure value to the control system; The control system is also connected to the first solenoid valve group, and the control system controls the switch state of the first solenoid valve group according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge, and short-circuits different turbine stages, thereby adjusting the compression ratio; The first solenoid valve group includes a plurality of first solenoid valves, each of the first solenoid valves is arranged in one-to-one correspondence with the turbine, and each of the first solenoid valves is connected to the flow port of the corresponding turbine and the gas path leading out of the flow port of the adjacent turbine; The control system is also connected to the motor, and the control system also controls the rotation speed of the motor according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge.

2. The automatic pressure-stabilizing molecular pump according to claim 1, characterized in that: The automatic pressure-stabilizing molecular pump further comprises: a second electromagnetic valve group, wherein the second electromagnetic valve group is connected to the gas path leading out of each level of flow outlet through micropores.

3. The automatic pressure-stabilizing molecular pump according to claim 2, characterized in that: The second solenoid valve group includes a plurality of second solenoid valves, which are arranged one by one with the turbines, and each of the second solenoid valves is connected to the flow port of the corresponding turbine and the gas path leading out of the flow port of the adjacent turbine through a micropore.

4. A control method for an automatic pressure-stabilizing molecular pump, characterized in that: Based on the automatic pressure-stabilizing molecular pump according to claim 3, the control method comprises: Obtaining target vacuum pressure; Setting the speed of the automatic pressure-stabilizing molecular pump according to the target vacuum pressure; Read the pressure value detected by the vacuum gauge; Controlling the switch state of the first solenoid valve group according to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge; The step of setting the rotation speed of the automatic pressure-stabilizing molecular pump according to the target vacuum pressure comprises: Determine the vacuum level of the target vacuum pressure, the vacuum level includes a first vacuum segment and a second vacuum segment, the first vacuum segment is lower than the second vacuum segment, and the sum of the first vacuum segment and the second vacuum segment is equal to the vacuum pressure range; When the target vacuum pressure belongs to the first vacuum section, the rotation speed of the automatic pressure-stabilizing molecular pump is set to a first rotation speed; When the target vacuum pressure belongs to the second vacuum segment, the rotation speed of the automatic pressure-stabilizing molecular pump is set to the second rotation speed.

5. The control method of the automatic pressure-stabilizing molecular pump according to claim 4, characterized in that: According to the difference between the target vacuum pressure and the pressure value detected by the vacuum gauge, controlling the switch state of the first solenoid valve group includes: When the pressure value is less than the target vacuum pressure, closing the preset solenoid valve in the first solenoid valve group; When the pressure value is greater than the target vacuum pressure, the preset solenoid valve in the first solenoid valve group is opened.

6. The control method of the automatic pressure-stabilizing molecular pump according to claim 5, characterized in that: When the pressure value is greater than the target vacuum pressure, opening the preset solenoid valve in the first solenoid valve group comprises: Opening a preset solenoid valve in the second solenoid valve group; It is determined whether the pressure value is better than the target vacuum pressure, and when the pressure value is better than the target vacuum pressure, a preset solenoid valve in the first solenoid valve group is opened.

7. The control method of the automatic pressure-stabilizing molecular pump according to claim 6, characterized in that: It is determined whether the pressure value is better than the target vacuum pressure. When the pressure value is better than the target vacuum pressure, the rotation speed of the automatic pressure-stabilizing molecular pump and the switch states of the first solenoid valve group and the second solenoid valve group are adjusted.

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