JP2016169728A - Vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a vacuum pump that can restrain a foreign body from entering a gap between rotors, etc., and that can achieve a low ultimate pressure.SOLUTION: The vacuum pump comprises two rotating shafts formed so as to extend in a first axis direction, a rotor casing, rotors, and a shielding part. In the rotor casing, a rotor chamber provided along the two rotating shafts, a suction port communicating with the rotor chamber, and a discharge port communicating with the rotor chamber are formed. The rotors are attached to the two rotating shafts, and arranged in the rotor chamber. The shielding part is configured to prevent gas sucked from the suction port to the rotor chamber from directly going toward a gap between the rotors, and provided between the suction port and the inside of the rotor chamber.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vacuum pump.

  In the manufacturing process of a semiconductor device and a liquid crystal device, a dry vacuum pump is connected to a vacuum chamber, and a process gas introduced into the vacuum chamber is exhausted by the vacuum pump. In the process gas exhausted by the vacuum pump, a substance solidified by a reaction or the like in the vacuum chamber or a substance that easily solidifies may be mixed as a foreign substance.

  In the dry vacuum pump, a gap (clearance) between the rotor and the rotor or between the rotor and the casing is designed to be small. Therefore, when the solidified material enters the inside of the pump, it accumulates or bites into these gaps inside the pump, and the rotation of the rotor may be hindered. For this reason, the suction port of the dry vacuum pump may be provided with a trap or a filter that prevents the solidified material from entering the pump.

JP-A-5-332285

  If the suction of the process gas is inhibited at the suction port of the dry vacuum pump, the ultimate pressure of the vacuum chamber to which the dry vacuum pump is connected becomes high. For this reason, the traps and the like provided at the suction port of the dry vacuum pump are devised such as providing a large trap or providing a plurality of traps, which causes an increase in the size and cost of the manufacturing process apparatus. In addition, if solidified material accumulates on the trap or the like to cause clogging, the suction of the process gas of the dry vacuum pump is hindered, so that maintenance such as cleaning or replacement of the trap or the like may be frequently required.

  Further, as a dry vacuum pump, a screw type, a roots type, a claw type, and the like are known. Generally, a screw type vacuum pump is less affected by foreign matter than a roots type and a claw type vacuum pump. However, particularly when a light gas such as hydrogen is used as the process gas, the Roots type and Claw type vacuum pumps can obtain a lower ultimate pressure than the screw type vacuum pump.

  The present invention has been made in view of the above problems, and an object of the present invention is to propose a vacuum pump that can suppress the entry of foreign matter into a gap such as between rotors and obtain a low ultimate pressure.

The vacuum pump of the present invention includes two rotating shafts formed to extend in the first axial direction, a rotor casing, a rotor, and a shielding portion. The rotor casing is formed with a rotor chamber provided along two rotation shafts, a suction port communicating with the rotor chamber, and a discharge port communicating with the rotor chamber. The rotor is attached to two rotating shafts and is disposed in the rotor chamber. The shielding portion is configured to prevent the gas sucked into the rotor chamber from the intake port from being directly directed to the gap between the rotors, and is provided between the intake port and the rotor chamber interior.
According to this vacuum pump, the shielding portion is provided between the air inlet and the rotor chamber, and the shielding portion prevents the gas sucked from the air inlet into the rotor chamber from being directed directly to the gap between the rotors. . Thereby, accumulation or biting of foreign matter in the gap between the rotors can be suppressed.

The rotor may be a roots type or a claw type rotor.
In this way, a low ultimate pressure by the vacuum pump can be realized particularly when a light gas such as hydrogen is used as the process gas.

Further, the shielding part may be provided in front of the gap between the rotors when viewed from the air inlet toward the rotor chamber.
If it carries out like this, it can suppress that a foreign material goes directly to the clearance gap between rotors.

Further, the shielding portion may be provided between the two rotating shafts when viewed from the suction port toward the rotor chamber inside the rotor.
If it carries out like this, it can suppress that a foreign material goes directly to the clearance gap between rotors.

Moreover, the shielding part may have a tapered shape with a narrow upstream side and a wide downstream side, or may have a curved shape that is convex toward the upstream side.
In this way, it is possible to effectively prevent foreign matters from being directed directly into the gap between the rotors.

Further, the rotor chamber may include a multi-stage rotor chamber connected to each other by a gas flow path, and the rotor may include a multi-stage rotor disposed in each of the multi-stage rotor chambers. The shielding portion may be provided between the intake port and the first-stage rotor chamber in the multi-stage rotor chamber.
If it carries out like this, it can suppress that a foreign material heads directly into the clearance gap between rotors in the rotor interior part of the first stage.

Moreover, you may further provide the foreign material capture | acquisition part which has at least one of the trap or filter arrange | positioned in the gas flow path which connects between the stages in a multistage rotor chamber.
If it carries out like this, the foreign material contained in gas can be capture | acquired by the foreign material capture | acquisition part of a gas flow path. In addition, since the foreign matter catching part for catching foreign matter is provided between the stages in the multi-stage rotor chamber, the suction from the chamber to the first stage rotor chamber is not hindered by the foreign matter catching part, and a low ultimate pressure is obtained. Can do. Further, since the foreign matter catching portion is provided downstream of the first stage rotor chamber where the pressure is higher than that of the intake port, a foreign matter catching portion having a simple configuration can be used. Further, even when foreign matter is accumulated in the foreign matter catching portion, the influence on the intake air of the first-stage rotor chamber is small, so the frequency of maintenance of the foreign matter catching portion can be reduced.

  In addition, the foreign matter capturing unit may be disposed in a gas flow path that connects the first-stage rotor chamber and the next-stage rotor chamber among the multi-stage rotor chambers.

Moreover, the clearance gap between a rotor casing and a multistage rotor, or the clearance gap between the multistage rotors in each of a multistage rotor chamber may be formed smaller downstream than the upstream of a foreign material capture part.
By so doing, it is possible to suppress the accumulation or biting of foreign matter upstream of the foreign matter catching section, and to achieve a low ultimate pressure by a vacuum pump.

The vacuum pump may be further provided with a pressure sensor that is provided in the gas flow channel upstream of the foreign substance capturing unit and detects the pressure.
In this way, it is possible to measure the maintenance timing of the foreign substance capturing unit based on the detection of the pressure sensor.

Further, the foreign matter trapping part may have a net-like or porous filter.
By so doing, it is possible to suitably capture foreign matter flowing in the gas flow path.

  Further, the air inlet may be connected to a chamber in which a gas containing non-sublimable foreign matter is generated.

It is a schematic block diagram which shows the vacuum pump apparatus of this embodiment. It is a schematic block diagram which shows the vacuum pump apparatus of this embodiment from another cross section. It is sectional drawing which shows schematic structure in the 1st stage | paragraph rotor chamber of this embodiment. It is sectional drawing which shows schematic structure in the 2nd stage | paragraph rotor chamber of this embodiment. It is the schematic which shows an example of a foreign material capture part. It is the schematic which shows another example of a foreign material capture part. It is a schematic block diagram which shows the vacuum pump apparatus of a 1st modification. It is a block diagram which shows schematic structure of the vacuum pump apparatus of a 2nd modification.

  FIG. 1 is a schematic configuration diagram showing a vacuum pump device of the present embodiment. FIG. 2 is a schematic configuration diagram showing the vacuum pump device of the present embodiment from another cross section. The vacuum pump device of this embodiment is connected to, for example, a vacuum chamber (not shown) in which a CVD process is performed, and discharges gas from the vacuum chamber. The vacuum pump device according to the present embodiment can be suitably used for a vacuum chamber in which solid foreign matter is contained in the gas in the vacuum chamber, and particularly preferably when the solid foreign matter is non-sublimable. However, it is not limited to this. Moreover, although the vacuum pump apparatus of this embodiment can be utilized suitably with respect to the vacuum chamber in which light gas, such as hydrogen, produces, it is not limited to this.

  FIG. 1 shows a cross section including an axis AR1 of one pump rotor 310 of the pair of pump rotors 310, 410 included in the vacuum pump device 100. FIG. 2 shows a cross section including the rotation center axes AR1 and AR2 of both the pair of pump rotors 310 and 410 included in the vacuum pump device 100. However, in FIG. 1, the pump rotor 310 is not illustrated in consideration of the visibility of the drawing. Further, FIG. 1 also shows a block diagram of the pressure sensor 620 and the control unit 700 constituting the vacuum pump device 100.

  As shown in FIGS. 1 and 2, the vacuum pump device 100 includes a pair of main shafts (two rotating shafts) 300 and 400, a pair of pump rotors 310 and 410, a motor 200, a casing 500, and a foreign matter capturing unit. 600, a pressure sensor 620, and a control unit 700.

  The main shafts 300 and 400 are formed extending in the directions of the axes AR1 and AR2. The main shafts 300 and 400 are pivotally supported on the casing 500 by bearings 302 and 402. A pair of timing gears 380 and 480 are attached to the main shafts 300 and 400, and the main shafts 300 and 400 rotate in synchronization with the power from the motor 200. Pump rotors 310 and 410 are attached to the main shafts 300 and 400 so as to rotate integrally with the rotation of the main shafts 300 and 400, respectively.

  The pair of pump rotors 310 and 410 constitutes a multistage compression stage. The pump rotor 310 includes a first stage rotor (first stage rotor) 312, a second stage rotor (next stage rotor) 314, and a third stage rotor 316 (final stage rotor) that are attached to the main shaft 300 at intervals. ). The pump rotor 410 includes a first stage rotor (first stage rotor) 412, a second stage rotor 414 (next stage rotor), and a third stage rotor (final stage rotor) attached to the main shaft 400 at intervals. Rotor) 416.

  In the casing 500, a multi-stage rotor chamber 520, an intake port 510, an exhaust port 540, and gas flow paths 530 and 532 are formed. Further, the casing 500 is provided with a shielding portion 580 between the intake port 510 and the inside of the first stage rotor chamber 522, that is, upstream of the first stage rotors 312 and 412.

  The multi-stage rotor chamber 520 includes a first-stage rotor chamber (first-stage rotor chamber) 522, a second-stage rotor chamber (next-stage rotor chamber) 524, a third-stage rotor chamber (final-stage rotor chamber) 526, Is provided. In the first stage rotor chamber 522, the second stage rotor chamber 524, and the third stage rotor chamber, the first stage rotors 312 and 412 of the pump rotors 310 and 410, the second stage rotors 314 and 414, and the third stage respectively. Stage rotors 316 and 416 are accommodated correspondingly. The first stage rotor chamber 522 communicates with an intake port 510 connected to a vacuum chamber (not shown), and the third stage rotor chamber 526 communicates with an exhaust port 540. The first stage rotor chamber 522 and the second stage rotor chamber 524 are connected via a gas flow path 530 provided on the outer peripheral side of the rotor chamber 520. Similarly, the second stage rotor chamber 524 and the third stage rotor chamber 526 are connected via a gas flow path 532 provided on the outer peripheral side of the rotor chamber 520. With this configuration, when process gas is drawn into the first stage rotor chamber 522 from the intake port 510, the process gas is in the order of the gas flow path 530, the second stage rotor chamber 524, the gas flow path 532, and the third stage rotor chamber 526. Is finally discharged from the exhaust port 540 to the outside.

  FIG. 3 is a cross-sectional view showing a schematic configuration in the first stage rotor chamber of the present embodiment. In FIG. 3, a cross section perpendicular to the axes AR1 and AR2 in the first stage rotor chamber 522 is shown. In the first stage rotor chamber 522, the first stage rotors 312 and 412 are arranged to face each other. Minute gaps CF 1 and CF 2 are formed between the first stage rotors 312 and 412 and between the first stage rotors 312 and 412 and the inner surface of the casing 500. The first stage rotors 312 and 412 rotate in opposite directions as the main shafts 300 and 400 rotate, and pump the gas flowing in from the intake port 510. At this time, the gas is pumped so as to pass between the first stage rotors 312 and 412 and the inner surface of the casing 500 without passing between the first stage rotors 312 and 412 (indicated by a thick arrow in FIG. 3). reference).

  A shield 580 is provided at the gas inlet to the first stage rotors 312 and 412. When the shielding portion 580 is viewed from the intake port 510 toward the gas outlet of the first stage rotor chamber 522 (when viewed along the direction AD in FIG. 3), the shielding section 580 is formed between the first stage rotors 312 and 412. It arrange | positions so that the clearance gap CF1 (sealing site | part) may be covered. In other words, the shielding portion 580 is provided between the main shafts 300 and 400 when viewed from the intake port 510 toward the gas outlet of the first stage rotor chamber 522. The shield 580 is preferably formed so that the boundary between the first stage rotors 312 and 412 cannot be seen when viewed from the inlet 510 toward the gas outlet of the first stage rotor chamber 522. The shielding part 580 may be formed integrally with the casing 500, or may be prepared as a member different from the casing 500 and assembled to the casing 500.

The shielding unit 580 guides the gas sucked into the first stage rotor chamber 522 from the intake port 510 in a direction away from the gap CF1 between the first stage rotors 312 and 412. The material and shape of the shielding part 580 may be designed so that the gas is suitably guided. For example, the shielding portion 580 may be a tapered member that is narrow on the upstream side and wide on the downstream side, or may be a curved member that is convex toward the upstream side. By such a shielding portion 580, it is possible to suppress the gas sucked into the first stage rotor chamber 522 from the intake port 510 from going directly to the gap CF1 between the first stage rotors 312 and 412. When foreign matter is caught in the gap CF1 between the first stage rotors 312 and 412 that are not gas passages, the first stage rotors 312 and 412 are pushed away from each other, and the first stage rotors 312 and 412 and the casing 500 May come into contact. On the other hand, according to this embodiment, the shielding unit 580 causes the first
It is possible to prevent foreign matter from being caught in the gap CF1 between the stage rotors 312 and 412 and to improve the durability of the vacuum pump device 100.

  FIG. 4 is a cross-sectional view showing a schematic configuration in the second stage rotor chamber of the present embodiment. Note that FIG. 1 corresponds to a view taken along arrows II in FIGS. As shown in FIGS. 3 and 4, in the second stage rotor chamber 524, the second stage rotors 314 and 414 are arranged to face each other, as in the first stage rotor chamber 522. In addition, minute gaps CL1 and CL2 are formed between the second stage rotors 314 and 414 and between the second stage rotors 314 and 414 and the inner surface of the casing 500.

  Here, in the present embodiment, the gap CL1 between the second stage rotors 314 and 414 in the second stage rotor chamber 524 is smaller than the gap CF1 between the first stage rotors 312 and 412 in the first stage rotor chamber 522. . In other words, the gap CF1 between the first stage rotors 312 and 412 is formed larger than the gap CL1 between the second stage rotors 314 and 414. This is because, like the shielding portion 580, foreign matter is prevented from being caught in the gap CF1 between the first-stage rotors 312 and 412 that are not gas passages. Further, in the first rotor chamber 522 connected to the vacuum chamber, even if the gap CF1 is formed large, the influence on the performance of the vacuum pump device 100 is small. Therefore, with such a configuration, it is possible to ensure the performance of the vacuum pump device 100 and further suppress the accumulation or biting of foreign matter in the gap CF1 between the first stage rotors 312 and 414.

  Further, in the present embodiment, the clearance CL2 between the second stage rotors 314 and 414 in the second stage rotor chamber 524 and the inner surface of the casing 500 is equal to the first stage rotors 312 and 412 in the first stage rotor chamber 522 and the casing 500. It is smaller than the gap CF2. In other words, the gap CF2 between the first stage rotors 312 and 412 and the casing 500 is formed larger than the gap CL2 between the second stage rotors 314 and 414 and the casing 500. With such a configuration, the performance of the vacuum pump device 100 can be ensured, and the occurrence of foreign matter accumulation or biting in the first stage rotor chamber 522 can be more significantly suppressed. In the present embodiment, the gap in the third stage rotor chamber 526 that is downstream from the foreign matter catching section 600 is also the gap in the first stage rotor chamber 522 in the same manner as the gaps CL1 and CL2 in the second stage rotor chamber 524. It is formed smaller than CF1 and CF2.

  Returning to FIG. The foreign matter capturing unit 600 captures foreign matter (for example, solidified material) contained in the process gas. As shown in FIG. 1, the foreign matter capturing unit 600 is provided in a gas flow path 530 that connects the first-stage rotor chamber 522 and the second-stage rotor chamber 524. That is, the gas discharged from the first stage rotor chamber 522 passes through the foreign matter trapping part 600 and flows into the second stage rotor chamber 524.

For example, as shown in FIG. 5, the foreign substance capturing unit 600 includes a cylindrical casing 640 and a filter 650 accommodated in the casing 640. The filter 650 can be formed of a porous or mesh body. The filter 650 may be designed so that foreign substances contained in the process gas are suitably captured and the resistance passing through the filter 650 is within an allowable range. For example, the filter 650 can be a porous body in which pores smaller than the foreign matter are formed based on the foreign matter contained in the process gas. In addition, the foreign matter trapping unit 600 may be provided with multiple filters with low resistance so that the resistance when the process gas passes becomes small. Further, as shown in FIG. 6, the foreign material capturing unit 600 may include a casing 640 and a plurality of filters 660 in which holes 662 are formed. In the example shown in FIG. 6, each filter 660 is housed in a cylindrical casing 640 such that each hole 662 is arranged at a different position with respect to the flow direction of the process gas. In the example shown in FIG. 6, each filter 660 has one hole 662, but two or more holes 662 may be formed. In this case, for example, in each adjacent filter 660, each filter 660 may be accommodated in the cylindrical casing 640 such that each hole 662 is disposed at a different position with respect to the flow direction of the process gas. .

  The pressure sensor 620 is provided upstream of the foreign material capturing unit 600 and detects the pressure of the gas flow path 530. In other words, the pressure sensor 620 is provided between the first stage rotor chamber 522 and the foreign matter catching unit 600. The pressure sensor 620 detects the exhaust pressure of the first stage rotor chamber 522 and the intake pressure of the foreign matter trapping part 600. The pressure sensor 620 transmits the detected pressure signal of the gas flow path 530 to the control unit 700.

  The control unit 700 controls the overall operation of the vacuum pump device 100, and also functions as a data storage unit 710, a data analysis unit 720, and a notification unit 730. In the present embodiment, the control unit 700 is configured as an information processing apparatus having a CPU and a memory, and the CPU executes a program stored in the memory to realize a required function. However, at least a part of the function of the control unit 700 may be realized by a dedicated hardware circuit. In addition, each function of the control unit 700 may be distributed in two or more devices.

  The data storage unit 710 receives the detection signal from the pressure sensor 620 and stores it for a certain period. The data storage unit 710 stores an initial value for pressure detection of the pressure sensor 620. The initial value is such that the vacuum pump device 100 is driven during the rated operation of the vacuum pump device 100 in a state where no foreign matter adheres to the inside of the foreign matter catching unit 600, that is, when the foreign matter catching unit 600 is replaced or maintained. The value actually detected by the pressure sensor 620 is used. The measurement and storage of the initial value may be performed before the vacuum pump device 100 is shipped, or may be performed after the vacuum pump device 100 is installed at the place of use (for example, during a test run). As the initial value, a value set in advance by design may be used.

  The data analysis unit 720 analyzes the foreign matter accumulation state of the foreign matter catching unit 600 based on the detection signal from the pressure sensor 620. In this embodiment, the data analysis unit 720 determines that the detected pressure value for a certain period (for example, 1 hour) stored in the data storage unit 710 is separated from the initial value stored in the data storage unit 92 by a predetermined amount. Judge whether or not. When at least one of the detected pressure values is away from the initial value by a predetermined amount, the data analysis unit 720 determines that maintenance or replacement of the foreign matter capturing unit 600 is necessary. However, the data analysis unit 720 may perform analysis using an average value instead of or in addition to the instantaneous value.

  The notification unit 730 notifies the analysis result by the data analysis unit 720. The notification can be performed by an arbitrary method. For example, the control unit 700 itself may give a warning by sound or screen display, or may send a warning signal to the central control room. The user of the vacuum pump device 100 can measure the replacement or maintenance timing of the foreign matter capturing unit 600 based on the notification by the notification unit 730.

  In the vacuum pump device 100, when the motor 200 is driven, the timing gear 380 and the pump rotor 310 are rotationally driven. As the timing gears 380 and 480 mesh with each other, the pump rotor 410 is also rotationally driven. The pair of pump rotors 310 and 410 has a slight gap between the inner surface of the rotor chamber 520 and between the first stage rotors 312 and 412, the second stage rotors 314 and 414, and the third stage rotors 316 and 416. , And rotate synchronously in the opposite direction without contact. As the pair of pump rotors 310 and 410 rotate, the process gas introduced from the intake port 510 is compressed and transferred by the first stage rotors 312 and 412, the second stage rotors 314 and 414, and the third stage rotors 316 and 416. And is discharged from the exhaust port 540.

  In the vacuum pump device 100 of the present embodiment described above, the net-like or porous foreign matter trapping part 600 that traps the foreign matter contained in the process gas is provided between the first stage rotor chamber 522 and the second stage rotor chamber 524. The gas channel 530 is disposed. Thereby, there is no hindrance by the foreign matter capturing part 600 against the intake air from the vacuum chamber to the first stage rotor chamber 522. Therefore, the ultimate pressure in the vacuum chamber by the vacuum pump device 100 can be lowered. In addition, since the foreign matter catching part 600 is provided downstream of the first stage rotor chamber 522 where the pressure is higher than that of the intake port 510, the foreign matter catching part 600 having a simple configuration can be used. Further, even when foreign matter is accumulated in the foreign matter catching part 600, the influence on the intake air of the first stage rotor chamber 522 is small, and the maintenance frequency of the foreign matter catching part 600 can be reduced.

  Moreover, in the vacuum pump apparatus 100 of this embodiment, the foreign material capture | acquisition part 600 is provided in the gas flow path 530 which connects the multistage rotor chamber 520 along two rotating shafts. For this reason, for example, in a system in which the main pump is connected to the subsequent stage of the booster pump, it is possible to reduce the number of elements constituting the system as compared with a system in which the foreign matter capturing unit 600 is provided between the booster pump and the main pump. Therefore, a simple configuration including the control system can be achieved, and an inexpensive and compact configuration can be achieved.

  Moreover, in the vacuum pump device 100 of the present embodiment, the pressure sensor 620 is provided between the foreign matter trapping part 600 and the first stage rotor chamber 522, so that the foreign matter trapping part 600 is based on the detection of the pressure sensor 620. The timing of maintenance can be measured.

  Further, the vacuum pump device 100 according to the present embodiment has a gap between the first stage rotors 312 and 412 when viewed from the inlet port 510 toward the gas outlet (exhaust port) of the first stage rotor chamber 522. The shielding part 580 which covers is provided. Thereby, it can suppress that a foreign material goes directly to clearance gap CF1 between 1st stage | paragraph rotors 312 and 412, and can improve the durability of the vacuum pump apparatus 100. FIG.

  In the vacuum pump device 100 of the above-described embodiment, a roots type vacuum pump device is used, but a claw type vacuum pump device may be used. The vacuum pump device 100 has three compression stages, but may be a multistage vacuum pump apparatus having two or four or more compression stages, or a single stage compression instead of a multistage type. It is good also as a vacuum pump apparatus which has a stage.

  In the vacuum pump device 100 according to the above-described embodiment, the foreign matter capturing unit 600 is provided in the gas flow path 530 between the first stage rotor chamber 522 and the second stage rotor chamber 524. However, the foreign substance capturing unit 600 may be installed in a gas flow path that connects the stages of the multistage rotor chamber 520. For example, as shown in the vacuum pump device 100A of the modified example of FIG. 7, the foreign matter capturing unit 600A may be provided in the gas flow path 532 between the second stage rotor chamber 524 and the third stage rotor chamber 526. . Even if the gap between the casing 500 and the pump rotors 310 and 410 in the rotor chamber 520 and the gap between the pump rotors 310 and 410 are formed large in the upstream near the vacuum chamber, the performance of the pump device 100A is improved. Based on less impact. For this reason, the foreign matter catching part 600A is provided in the gas flow path between the stages of the multistage rotor chamber 520, and the upstream side of the foreign matter catching part 600A is designed to be less influenced by the foreign matter, and the downstream side can secure the performance of the pump device 100A. Just design.

In the vacuum pump device 100 according to the above-described embodiment, the multistage pump rotors 310 and 410 and the rotor chamber 520 along the two main shafts 300 and 400 have been described. However, the foreign matter capturing unit 600 may be provided in a vacuum pump system including a plurality of compression stages for evacuating the vacuum chamber. FIG. 8 is a block diagram showing a schematic configuration of a modified vacuum pump system. As shown in FIG. 8, the vacuum pump system 100 </ b> B includes a plurality of compression stages 20 that evacuate the vacuum chamber 10. A foreign matter trapping portion 600 is provided in the gas flow path 40 between the first compression stage 20A connected to the vacuum chamber 10 and the next compression stage 20B. Here, the first-stage compression stage 20A is a first pump apparatus (for example, a booster pump), and the second-stage and subsequent compression stages are second pump apparatuses (for example, a main pump) having multiple stages of compression. There may be. Also in this case, the same effect as the above-described embodiment can be obtained.

  In the vacuum pump device 100 according to the above-described embodiment, the foreign matter capturing unit 600 includes the net-like or porous filter 650. However, the foreign material capturing unit 600 is not limited to such an example, and may be any as long as it has at least one of a trap and a filter. Moreover, the foreign material capturing part 600 may be made of a material such as a nonwoven fabric in which holes are irregularly formed.

  In the vacuum pump device 100 according to the above-described embodiment, the control unit 700 notifies the maintenance timing of the foreign matter capturing unit 600 based on the detection signal from the pressure sensor 620, but only the detection value of the pressure sensor 620 is used. It may be stored or notified. In addition, the maintenance timing of the foreign substance capturing unit 600 may be analyzed based on the ultimate pressure of the vacuum chamber without providing the pressure sensor 620. In addition, maintenance of the foreign material capturing unit 600 may be performed every predetermined period.

  In the vacuum pump device 100 of the above-described embodiment, the shielding part 580 is provided upstream of the first stage rotors 312 and 314. However, such a shielding part 580 may not be provided. In addition, the shielding unit 580 can be applied to a single-stage vacuum pump apparatus. Further, the shielding portion 580 may be provided only between the air inlet 510 and the inside of the first stage rotor chamber 522, or may be provided upstream of the plurality of rotor chambers 520, for example, as shown in FIG. Good. Further, as shown in FIG. 7, the shielding portion 580 is provided in the rotor chamber 520 upstream of the foreign matter capturing portion 600 (see the shielding portions 580 and 580A), and may not be provided in the downstream rotor chamber 520. Good.

  In the vacuum pump device 100 of the above-described embodiment, the gap CL1 between the second stage rotors 314 and 414 is smaller than the gap CF1 between the first stage rotors 312 and 412. Further, in the radial direction of the pump rotors 310 and 410 (directions perpendicular to the axes AR1 and AR2 of the main shafts 300 and 400), the clearance CL2 between the second stage rotors 314 and 414 and the casing 500 is the first stage rotors 312 and 412. And the gap CF2 between the casing 500 and the casing 500. However, it is not limited to this example. For example, the clearance CL3 between the second stage rotors 314 and 414 and the casing 500 in the directions of the axes AR1 and AR2 of the main shafts 300 and 400 is formed smaller than the clearance CF3 between the first stage rotors 312 and 412 and the casing 500. (See FIG. 2). Further, at least one of the clearance CF1 between the first stage rotors 312 and 412 and the clearance CF2 and CF3 between the first stage rotors 312 and 412 and the casing 500 is the clearance CL1 between the second stage rotors 314 and 414, the second stage. It may be formed larger than the gaps CL2 and CL3 between the rotors 314 and 414. Even with such a configuration, the same effects as the vacuum pump device 100 of the embodiment can be obtained.

  Although the embodiments of the present invention have been described above, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof. In addition, any combination of the embodiment and the modified example is possible within a range where at least a part of the above-described problems can be solved or a range where at least a part of the effect can be achieved, and is described in the claims and the specification. Any combination or omission of each component is possible.

10 Vacuum chamber 20 Multiple compression stages 20A First compression stage 20B Next compression stage 40 Gas flow path 100 Vacuum pump 300, 400 Main shaft 310, 410 Pump rotors 312, 412 First stage rotors 314, 414 Second stage rotor 316, 416 Third stage rotor 500 Casing 510 Inlet 520 Rotor chamber 522 First stage rotor chamber 524 Second stage rotor chamber 526 Third stage rotor chamber 530, 532 Gas flow path 540 Exhaust port 580 Shielding part 600 Foreign matter capturing part 620 Pressure sensor 640 Casing 650 Filter 660 Filter 662 Hole 700 Control unit

Claims (13)

Two rotating shafts formed extending in the first axial direction;
A rotor casing formed with a rotor chamber provided along the two rotation axes, an intake port communicating with the rotor chamber, and an exhaust port communicating with the rotor chamber;
A rotor attached to the two rotating shafts and disposed in the rotor chamber;
A shielding portion provided between the intake port and the rotor chamber interior, configured to prevent the gas sucked into the rotor chamber from the intake port from being directed directly to the gap between the rotors;
With vacuum pump. The vacuum pump according to claim 1,
The rotor is a Roots type or Claw type rotor,
Vacuum pump. The vacuum pump according to claim 1 or 2,
The shielding portion is provided in front of a gap between the rotors when viewed from the intake port toward the rotor chamber interior,
Vacuum pump. The vacuum pump according to any one of claims 1 to 3,
The shield is provided upstream of the rotor and between the two rotating shafts when viewed from the suction port toward the rotor chamber.
Vacuum pump. The vacuum pump according to any one of claims 1 to 4,
The shielding part has a tapered shape with a narrow upstream side and a wide downstream side,
Vacuum pump. The vacuum pump according to any one of claims 1 to 4,
The shielding part has a curved shape that is convex toward the upstream,
Vacuum pump. The vacuum pump according to any one of claims 1 to 6,
The rotor chamber has multi-stage rotor chambers connected to each other by gas flow paths,
The rotor has a multistage rotor disposed in each of the multistage rotor chambers,
The shielding part is provided between the intake port and a first-stage rotor chamber inside the multi-stage rotor chamber,
Vacuum pump. The vacuum pump according to claim 7,
It further comprises a foreign matter capturing part having at least one of a trap or a filter disposed in a gas flow path connecting the stages in the multistage rotor chamber,
Vacuum pump. A vacuum pump according to claim 8,
The foreign matter capturing part is disposed in a gas flow path that connects a first-stage rotor chamber and a next-stage rotor chamber among the multi-stage rotor chambers,
Vacuum pump. The vacuum pump according to claim 8 or 9, wherein
The gap between the rotor casing and the multi-stage rotor, or the gap between the multi-stage rotors in each of the multi-stage rotor chambers, is formed smaller downstream than the upstream of the foreign matter capturing part,
Vacuum pump. The vacuum pump according to any one of claims 8 to 10,
A pressure sensor that is provided in the gas flow path upstream of the foreign substance capturing unit and detects pressure;
Vacuum pump. The vacuum pump according to any one of claims 8 to 11,
The foreign matter capturing part has a net-like or porous filter,
Vacuum pump. The vacuum pump according to any one of claims 1 to 12,
The inlet is connected to a chamber in which a gas containing non-sublimable foreign matter is generated.
Vacuum pump.

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