JP7450405B2 - Vacuum pump - Google Patents

Description

The present invention relates to a vacuum pump.

Reaction devices used in semiconductor manufacturing and the like use vacuum pumps to exhaust powdered reaction products, gaseous reaction products, reaction raw materials, and the like. Reaction products and the like exhausted from the reactor pass through a flow path within the vacuum pump. At that time, reaction products and the like adhere to or precipitate on the wall surface within the channel depending on the temperature and pressure conditions. If the amount of deposits increases, the operation of the vacuum pump will be hindered, so maintenance is required to remove such deposits.

In some vacuum pumps, a capacitive film thickness sensor measures the thickness of such deposits, and based on the sensor output value, maintenance can be performed before the vacuum pump becomes operational. (For example, see Patent Documents 1 and 2).

In another vacuum pump, it is detected that the thickness of the deposit deposited between the electrode pair has reached a predetermined thickness by decreasing the rate of increase in the capacitance of the electrode pair (for example, Patent Document 3 reference).

In yet another vacuum pump, a communication path is provided in the flow path, and deposits are detected based on the range of pressure fluctuation detected by a pressure sensing section provided in the communication path (see, for example, Patent Document 4).

Japanese Unexamined Patent Publication No. 6-101655 Japanese Patent Application Publication No. 6-109409 Japanese Patent Application Publication No. 2018-159632 JP2011-247823A

In the flow path within the vacuum pump, the lower the temperature and the higher the pressure, the more deposits are likely to separate out. Generally, the pressure is higher downstream in the flow path. Regarding temperature, in order to suppress the generation of deposits, a part of the flow path may be heated to a high temperature using a heater.

On the other hand, in order to increase the operating rate of the vacuum pump, it is preferable that the frequency of maintenance be small. Therefore, it is preferable to detect the maintenance time as late as possible without causing a problem in the operation of the vacuum pump.

However, it is important to note that the thickness of deposits (i.e., , appropriate maintenance timing) is difficult to detect.

In other words, in order to detect the deposit thickness in the direction perpendicular to the wall of the channel, for example, in the case of the capacitance method, it is necessary to install electrodes at two opposing positions on the wall of the channel. However, it is difficult to install electrodes if one wall is rotating. Furthermore, as described above, it is difficult to accurately detect the deposit thickness (for example, the deposit thickness just before blockage) based on the pressure in the flow path. In addition, when installing a capacitive thickness gauge inside a flow path, it is necessary to widen the gap between a pair of electrode plates in order to measure relatively large thicknesses with good sensitivity, which corresponds to appropriate maintenance periods. There is. However, when the spacing between the electrode plates is widened, increasing the area of the electrode plates for good sensitivity increases the size of the sensor, making it difficult to arrange the sensor within the flow path.

The present invention has been made in view of the above problems, and provides a vacuum pump that detects the thickness of deposits at the flow path position where the cause of trouble in operation of the vacuum pump occurs, just before the cause of the trouble occurs. The purpose is to obtain.

The vacuum pump according to the present invention has a flow path from a gas intake port to an exhaust port, and is arranged upstream or downstream of a predetermined flow path position where a cause of operational trouble of the vacuum pump occurs in the flow path. and a deposit sensor. The sediment sensor detects the presence or absence of sediment at the position where the sediment sensor is placed, without detecting the thickness of the sediment at the position where the sediment sensor is placed. When the detection state of the sensor changes from no deposit to presence of deposit, the thickness of the deposit at the predetermined flow path position described above becomes a predetermined thickness corresponding to the maintenance period for suppressing the cause. It's the location.

According to the present invention, it is possible to obtain a vacuum pump that detects the thickness of deposits at a flow path position where a cause of trouble in operation of the vacuum pump occurs, just before the cause occurs.

These and other objects, features and advantages of the present invention will become more apparent from the following detailed description in conjunction with the accompanying drawings.

FIG. 1 is a diagram showing the internal configuration of a vacuum pump according to Embodiment 1 of the present invention. FIG. 2 is a phase diagram illustrating precipitation of sediment components. FIG. 3 is a diagram illustrating the distribution of deposit thickness along the channel position. FIG. 4 is a diagram showing an example of the arrangement position of the deposit sensor in the first embodiment. FIG. 5 is a diagram illustrating the level of sediment accumulation in the sediment sensor. FIG. 6 is a block diagram showing the electrical configuration of the vacuum pump according to the first embodiment. FIG. 7 is a diagram showing an example of the arrangement position of the deposit sensor in the second embodiment. FIG. 8 is a diagram showing an example of a deposit sensor according to the third embodiment. FIG. 9 is a diagram showing an example of a deposit sensor according to the fourth embodiment. FIG. 10 is a diagram showing an example of a deposit sensor according to the fifth embodiment.

Embodiments of the present invention will be described below based on the drawings.

Embodiment 1.

FIG. 1 is a diagram showing the internal configuration of a vacuum pump according to Embodiment 1 of the present invention. The vacuum pump shown in FIG. 1 is a turbo-molecular pump, and includes a vacuum pump main body 10 including a casing 1, stator blades 2, rotor blades 3, rotor shaft 4, bearing part 5, motor part 6, suction port 7, and screw grooves. 8, and an exhaust port 9. The rotor blades 3 are fixed to a rotor shaft 4, and the rotor blades 3 and the rotor shaft 4 constitute a rotor 11.

The casing 1 has a substantially cylindrical shape, and accommodates a rotor 11, a bearing section 5, a motor section 6, etc. in its internal space, and has multiple stages of stator blades 2 fixed to its inner peripheral surface. The stator blades 2 are arranged at a predetermined elevation angle. A stator is composed of a casing 1 and stator blades 2.

Inside the casing 1, multiple stages of rotor blades 3a and multiple stages of stator blades 2 are arranged alternately in the height direction of the rotor axis (rotor axial height). The rotor blade 3 includes multiple stages of rotor blade portions 3a and a rotor inner cylinder portion 3b. Each rotor wing portion 3a extends from the rotor inner cylinder portion 3b and has a predetermined elevation angle. The rotor inner cylinder portion 3b extends in the radial direction to the end of the rotor blade portion 3a (first-stage rotor blade portion 3a) that is closer to the center of the rotor 11. In other words, the rotor inner cylinder portion 3b is a portion of the rotor blade 3 other than the rotor blade portion 3a. Further, a rotor center portion 12 is constituted by the rotor shaft 4 and the rotor cylindrical portion 3b. Therefore, the rotor center portion 12 is the range from the center of the rotor 11 to the end of the rotor blade portion 3a (first-stage rotor blade portion 3a) closer to the center of the rotor 11 in the radial direction. The rotor shaft 4 and the rotor blades 3 are connected by screws or the like.

The bearing section 5 is a bearing for the rotor shaft 4, and in this embodiment is a magnetically levitated bearing, and includes a sensor for detecting the deviation of the rotor shaft 4 in the axial and radial directions, and a sensor for detecting the deviation of the rotor shaft 4 in the axial and radial directions. The rotor shaft 4 is equipped with an electromagnet that suppresses the displacement of the rotor shaft 4. Note that the bearing method of the bearing portion 5 is not limited to the magnetic levitation type. The motor section 6 rotates the rotor shaft 4 using electromagnetic force.

The intake port 7 is an opening at the upper end of the casing 1, has a flange shape, and is connected to a chamber (not shown) or the like. Gas molecules fly into the intake port 7 from the chamber due to thermal movement or the like. The exhaust port 9 has a flange shape and discharges gas molecules sent from the rotor blade portion 3a and the stator blade 2.

The vacuum pump shown in FIG. 1 is of a composite blade type, which includes a threaded groove pump part with threaded grooves 8 at the rear stage of the turbomolecular pump part with the stator blades 2 and rotor blades 3a, but it may also be of a full-blade type. .

In the vacuum pump shown in FIG. 1, the gas flow path to be exhausted is from the intake port 7 to the exhaust port 9, and is the space between the intake port 7, the rotor 11, and the stator (stator blades 2 and casing 1). , a space between the thread groove 8 of the thread groove pump section and the rotor 11, and an exhaust port 9.

Furthermore, the vacuum pump shown in FIG. 1 is equipped with a deposit sensor disposed in the flow path upstream or downstream of a predetermined flow path position where the above-mentioned cause of operational trouble of the vacuum pump occurs. .

The sediment sensor detects the presence or absence of sediment at the placement position of the sediment sensor, and the placement position of the sediment sensor is determined when the detection state of the sediment sensor changes from no deposit to presence of deposit. , the thickness of the deposit at the above-mentioned predetermined channel position is set to a predetermined thickness (hereinafter referred to as maintenance period thickness) corresponding to the maintenance period for suppressing the above-mentioned causes.

Further, the deposit sensor is arranged on the wall surface of the flow path in the stator facing the rotor 11. For example, the deposit sensor is arranged on the bottom surface of the thread groove 8 of the thread groove pump section, on the stator wall surface facing the rotor blade section 3a, or the like.

Further, the above-mentioned predetermined flow path position is, for example, the outlet portion of the thread groove pump section. Note that, for example, when a heater for suppressing deposits is disposed, the above-mentioned predetermined flow path position may be a portion other than the portion heated by the heater.

FIG. 2 is a phase diagram illustrating the precipitation of deposit components (components contained in the gas to be exhausted and precipitated as deposits). FIG. 2(A) is a phase diagram showing the state of deposit components at each channel position immediately after the start of operation, and FIG. 2(B) is a phase diagram showing the state of deposit components at each channel position after a predetermined operating time has elapsed. It is a phase diagram showing the states of components.

Regarding a certain deposit component, as shown in FIG. 2(A), when the vacuum pump starts operating, the state of the deposit component at the outlet of the thread groove pump section is near the sublimation curve, and the deposit is in the vicinity of the sublimation curve. Although precipitation is easy to occur, the partial pressure is sufficiently low at the inlet of the thread groove pump section (the outlet of the turbomolecular pump) and the inlet of the turbomolecular pump, and the state of the deposit components is a gas region that deviates from the sublimation curve. , making it difficult for deposits to precipitate. At this point, the state of the deposit components at the location where the deposit sensor is placed is in the gas region, making it difficult for deposits to precipitate.

Thereafter, as the operating time of the vacuum pump passes, deposits begin to precipitate at the outlet of the threaded pump section, and as the flow path gradually narrows due to the deposits, as shown in Figure 2(B), The partial pressure on the upstream side (the inlet part of the thread groove pump section (outlet part of the turbomolecular pump), the inlet part of the turbomolecular pump, and the placement position of the deposit sensor) gradually increases, and the placement position of the deposit sensor increases. The state of the sediment components at is near the sublimation curve. Therefore, at this point, deposits are deposited at the position where the deposit sensor is placed, and the detection state of the deposit sensor changes to "deposit present". In other words, the deposit sensor is disposed at a position where the state of the deposit components is approximately on the sublimation curve when the deposit thickness at the outlet portion of the thread groove pump reaches a thickness corresponding to the maintenance time.

FIG. 3 is a diagram illustrating the distribution of deposit thickness along the channel position. As the pressure increases, the deposit thickness increases, so as shown in Figure 3, the deposit thickness at the assumed location of the cause (the above-mentioned predetermined flow path location) is equal to the maintenance period thickness (that is, the maintenance time thickness) The sediment sensor is placed at a position where the sediment sensor detects the lower detection limit of the sediment thickness (a predetermined sediment thickness lower than the maintenance period thickness) when the sediment sensor reaches the thickness obtained by subtracting the margin from the generated thickness. will be installed.

FIG. 4 is a diagram showing an example of the arrangement position of the deposit sensor in the first embodiment. FIG. 4(A) is a sectional view of the threaded groove pump portion in Embodiment 1, and FIG. 4(B) is a sectional view taken along line AA of the threaded groove pump portion in FIG. 4(A).

In this first embodiment, a plurality of deposit sensors 21-1 to 21-N (N>1) are arranged in the flow path. For example, as illustrated in FIG. Sensors 21-5 to 21-8 are arranged. Further, as shown in FIG. 4(B), each deposit sensor 21-i is arranged, for example, at the center of the bottom surface of the thread groove 8.

One of the plurality of deposit sensors 21-1 to 21-N is configured to detect deposits located upstream or downstream of a predetermined flow path position where the cause of trouble in operation of the vacuum pump as described above occurs. Used as an object sensor. Each of the plurality of deposit sensors 21-1 to 21-N detects the presence or absence of deposits at the position where the deposit sensor is placed.

Here, each deposit sensor 21-i is a photoelectric sensor such as an infrared sensor, and when the end of the deposit sensor 21-i protruding into the flow path is covered with deposits, the deposit sensor 21-i -The level of the sensor output signal of i changes.

Note that this photoelectric sensor includes a light emitting section and a light receiving section, and light emitted from the light emitting section toward the object is reflected or transmitted by the object and enters the light receiving section. Generally, in the case of a photoelectric sensor, once the deposit reaches a certain thickness and completely blocks the incident light to the photoelectric sensor, it is no longer possible to detect any further thickness, so the photoelectric sensor is used as a thickness gauge. It is difficult to use.

FIG. 5 is a diagram illustrating the level of deposits in the deposit sensor 21-i. As shown in FIG. 5, the thickness of the deposit increases from the deposition level A to the deposition level D toward the rotor wall surface 3c as the process time increases. Each deposit sensor 21-i does not detect the thickness of the deposit, but only detects the presence or absence of deposit on the deposit sensor 21-i. In other words, the level of the sensor output signal of the deposit sensor 21-i changes sharply at a point in time when the thickness of the deposit is low (for example, at the deposition level A).

FIG. 6 is a block diagram showing the electrical configuration of the vacuum pump according to the first embodiment. The vacuum pump according to the first embodiment further includes a control device 40 that electrically controls the vacuum pump main body 10. The control device 40 may be built into the vacuum pump, or the vacuum pump main body 10 and the control device 40 may be separate bodies that are detachable from each other.

As shown in FIG. 6, the control device 40 includes a controller 41, a communication device 42, and a display device 43. The controller 41 includes a processor, etc., and controls the motor section 6 of the vacuum pump main body 10, acquires the sensor output signal of the deposit sensor 21-i of the vacuum pump main body 10, and monitors the detection state of the deposit sensor 21-i. (In other words, the maintenance time is detected based on the sensor output signal). The communication device 42 is a peripheral interface, etc., and the display device 43 is various indicators, etc. When the controller 41 detects the maintenance time using the communication device 42 and the display device 43, it notifies the user that the maintenance time has been detected.

Note that the controller 41 makes a binary determination of "deposit present" or "deposit absent" based on the sensor output signal of the deposit sensor 21-i. Note that the controller 41 may perform binary judgment on the sensor output signal of the deposit sensor 21-i using a threshold value, or the deposit sensor 21-i may output a binary signal as the sensor output signal. .

Further, when a plurality of deposit sensors 21-1 to 21-N are arranged as in the first embodiment, the plurality of deposit sensors 21-1 to 21-N are electrically connected to the controller 41. (a) The controller 41 selects one specific sensor from among the plurality of deposit sensors 21-1 to 21-N (when the detection state changes from no deposits to presence of deposits, the controller 41 selects the above-mentioned predetermined flow rate) (b) select a deposit sensor located at a position where the thickness of the deposit at the road position becomes a predetermined thickness corresponding to the maintenance time; and (b) determine the maintenance time based on the detection state of the selected specific sensor. To detect. That is, when the specific sensor detects that "deposit is present", the controller 41 detects the maintenance time.

Since the gas passing through the flow path changes depending on the process in which the vacuum pump is used, the deposit thickness distribution as shown in FIG. 3 may also change depending on the process. Therefore, from the plurality of sediment sensors 21-1 to 21-N, when the sediment thickness at the position where the cause is assumed to occur reaches the maintenance period thickness, the sediment at the position where the sediment thickness will be the lower detection limit of the sediment sensor. Object sensor 21-i is selected and used for detecting maintenance time.

Such a deposit sensor 21-i to be selected is specified by, for example, an experiment, and set in the controller 41. Alternatively, for example, during maintenance, the correlation between the deposit thickness at the position where the cause is assumed to occur and the deposit thickness at each of the deposit sensors 21-1 to 21-N is identified, and based on that correlation, the Such a deposit sensor 21-i to be selected may be specified and set in the controller 41.

Further, when the controller 41 detects the sediment sensor 21-i whose detection state has changed from no sediment to presence of sediment among the plurality of sediment sensors 21-1 to 21-N, the controller 41 detects the detected sediment sensor 21-i. The maintenance time may be notified at the notification level corresponding to -i. For example, for the three sediment sensors 21-1 to 21-3, the controller 41 detects the change from no sediment to presence of sediment in the order of proximity to the above-mentioned predetermined flow path position. 3, the maintenance time is notified in the order of notification level "Caution", notification level "Warning", and notification level "Warning".

Next, the operation of the vacuum pump according to the first embodiment will be explained.

A chamber or the like is connected to the suction port 7 of the vacuum pump, and a control device 40 is electrically connected to the vacuum pump main body 10 (motor section 6, etc.), and the control device 40 (controller 41) is connected to the motor section. By operating 6, the rotor shaft 4 rotates, and the rotor blade portion 3a also rotates. As a result, gas molecules that have flown in through the intake port 7 are discharged from the exhaust port 9 by the rotor blade portion 3 a and the stator blade 2 through the flow path.

Deposits are deposited in various parts of the flow path due to the gas to be exhausted, and the thickness of the deposits gradually increases with process time. At the above-mentioned predetermined channel position, the rate of increase in the deposit thickness is high, and at the position where the deposit sensor 21-i is arranged, the rate of increase in the deposit thickness is low.

When the deposit thickness at the above-mentioned predetermined channel position reaches the maintenance time thickness, the deposit thickness at the placement position of the deposit sensor 21-i reaches the deposit detection lower limit thickness. , the detection state of the deposit sensor 21-i changes from no deposit to presence of deposit. When the detection state of the deposit sensor 21-i changes from no deposits to presence of deposits, the controller 41 detects this change in the detection state and notifies maintenance time.

As described above, according to the first embodiment, the deposit sensor 21-i detects a predetermined point in the flow path from the gas intake port 7 to the gas exhaust port 9 where the cause of operational trouble of the vacuum pump occurs. It is arranged upstream or downstream of the flow path position. Then, the deposit sensor 21-i detects the presence or absence of deposits at the position where the deposit sensor 21-i is placed, and the position where the deposit sensor 21-i is placed is such that the detection state of the deposit sensor 21-i is no deposit. When changing from to with deposits, the thickness of the deposits at the above-mentioned predetermined channel position becomes a predetermined thickness corresponding to the maintenance timing for suppressing the cause.

As a result, the deposit sensor 21-i, which is placed at a position different from the flow path position where the cause of the trouble in the operation of the vacuum pump occurs, detects the thickness of the deposit at that position shortly before the cause of the trouble occurs. is detected.

Embodiment 2.

In the second embodiment, a capacitive sensor is used as the deposit sensor instead of the deposit sensor (photoelectric sensor) in the first embodiment.

FIG. 7 is a diagram showing an example of the arrangement position of the deposit sensor in the second embodiment. 7(A) is a sectional view of the threaded groove pump part in Embodiment 2, and FIG. 7(B) is a BB sectional view of the threaded groove pump part in FIG. 7(A). (C) is a perspective view showing a deposit sensor in Embodiment 2.

In the second embodiment, as shown in FIG. 7(A), a sensor groove 31 is further formed on the bottom surface of the threaded groove 8 along the threaded groove 8, and as shown in FIG. 7(B), a sensor groove 31 is further formed along the threaded groove 8. A pair of electrodes 32a and 32b are arranged as a capacitive deposit sensor 32 on opposite sides of the sensor groove 31. Furthermore, in this second embodiment, a plurality of deposit sensors 32-1 to 32-N (N>1) are arranged, for example, at equal intervals in the sensor groove 31 formed in one or more thread grooves 8. ing.

Note that other configurations and operations of the vacuum pump according to Embodiment 2 are the same as in Embodiment 1, so their explanations will be omitted.

Embodiment 3.

FIG. 8 is a diagram showing an example of a deposit sensor according to the third embodiment. FIG. 8(A) is a diagram showing the top surface of the deposit sensor disposed in the thread groove pump part in Embodiment 3, and FIG. -A sectional view showing a cross section of the deposit sensor in Embodiment 3; In the third embodiment, a deposit sensor 21-i as shown in FIG. 8 is used.

The deposit sensor 21-i according to the third embodiment is a photoelectric sensor, and when the end of the deposit sensor 21-i exposed in the flow path is covered with deposits, the deposit sensor 21-i The level of the sensor output signal of i changes. For example, as shown in FIG. 8, the deposit sensor 21-i includes a light source 61 as a light emitting section, an optical sensor 62 as a light receiving section, and a window 63 forming an end of the deposit sensor 21-i. The light source 61 is, for example, an LED element, a laser resonator, etc., and the optical sensor 62 is, for example, a phototransistor, a photodiode, a photoconductive cell (such as a CdS cell), a photovoltaic cell, a CCD (Charge Coupled Device), or a CMOS (Complementary Metal Oxide). Semiconductor) sensors, infrared sensors, etc. Note that the light source 61 and the optical sensor 62 are arranged outside the pump, and instead of the light source 61 and the optical sensor 62, one end of two light guide members such as optical fibers is arranged, and the other end of the two light guide members is arranged. The end portions of the light guide member may be arranged to face the light source 61 and the optical sensor 62, respectively, and the light guiding member may guide light between the light source 61 and the optical sensor 62 and the thread groove 8.

When there is almost no deposit on the window 63, the light from the light source 61 travels through the window 63 to the rotor wall surface 3c, is reflected by the rotor wall surface 3c, and enters the optical sensor 62 through the window 63. On the other hand, when the deposits on the window 63 reach a certain thickness, the light from the light source 61 is blocked by the deposits and does not proceed to the rotor wall surface 3c, and the amount of light incident on the optical sensor 62 decreases. Therefore, when the end of the deposit sensor 21-i exposed in the flow path is covered with deposits, the level of the sensor output signal of the deposit sensor 21-i (optical sensor 62) changes. Thereby, each of the plurality of deposit sensors 21-1 to 21-N detects the presence or absence of deposits at the position where the deposit sensor is placed.

Note that other configurations and operations of the vacuum pump according to Embodiment 3 are the same as in Embodiment 1, so their explanations will be omitted.

Embodiment 4.

FIG. 9 is a diagram showing an example of a deposit sensor according to the fourth embodiment. FIG. 9(A) is a diagram showing a top surface of the deposit sensor in Embodiment 4, and FIG. 9(B) is a diagram showing a cross section of the deposit sensor in Embodiment 4. In the fourth embodiment, a deposit sensor 21-i as shown in FIG. 9 is used.

The deposit sensor 21-i according to the fourth embodiment is a photoelectric sensor similar to the deposit sensor 21-i in the first embodiment or the third embodiment, and is a photoelectric sensor that detects deposits exposed in the flow path. When the end of the sensor 21-i is covered with deposits, the level of the sensor output signal of the deposit sensor 21-i changes. For example, as shown in FIG. 9, the deposit sensor 21-i includes a light emitting section 71, a light receiving section 72, and a window 73 forming an end of the deposit sensor 21-i. As shown in FIG. 9, the light receiving section 72 is arranged around the light emitting section 71, and both are arranged concentrically.

Note that the other configurations and operations of the vacuum pump according to Embodiment 4 are the same as in Embodiment 1, so their explanations will be omitted.

Embodiment 5.

FIG. 10 is a diagram showing an example of a deposit sensor according to the fifth embodiment. The deposit sensor 21-i according to the fifth embodiment is a photoelectric sensor, and includes one or more light sources 81 common to the plurality of deposit sensors 21-1 to 21-N, and a light source 81 that is exposed in the flow path. A light sensor 82-i is provided. The light source 81 is disposed at the upper end and/or the lower end of the threaded pump section, and illuminates the rotor wall surface 3c and the threaded groove 8 through the gap 8a between the rotor wall surface 3c and the stator (threaded groove 8) in the threaded pump section. Irradiate light.

At least one of the plurality of optical sensors 82-1 to 82-N is arranged upstream or downstream of a predetermined flow path position where the above-mentioned cause of trouble in operation of the vacuum pump occurs. Ru. Each of the plurality of optical sensors 82-1 to 82-N generates a sensor output signal indicating the presence or absence of a deposit at the position where the deposit sensor is placed. If the end of the optical sensor 82-i is not covered with deposits, the light is reflected from the rotor surface and enters the optical sensor 82-i. On the other hand, when the end of the optical sensor 82-i is covered with deposits, the light no longer enters the optical sensor 82-i. Therefore, when the end of the optical sensor 82-i is covered with deposits, the level of the sensor output signal of the deposit sensor 21-i (optical sensor 82-i) changes.

Note that other configurations and operations of the vacuum pump according to Embodiment 5 are the same as in Embodiment 1, so their explanations will be omitted.

Note that various changes and modifications to the embodiments described above will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing its intended advantages. It is intended that such changes and modifications be included within the scope of the claims.

For example, in the first and second embodiments, the deposit sensors 21-i and 32-i are arranged upstream of the above-mentioned predetermined flow path position (here, the outlet portion of the threaded pump section). However, it may also be on the downstream side. In addition, in the first and second embodiments, the state (partial pressure and temperature) of the sediment components is changed in the phase diagram of the sediment components by narrowing the flow path at the predetermined flow path position. Moving from the gas region to the solid region, when the deposit thickness at the above-mentioned predetermined flow path position reaches a thickness corresponding to the maintenance period, to another position approximately on the sublimation curve, Deposit sensors 21-i and 32-i may also be provided.

In addition, in the first and second embodiments described above, the deposit sensors 21-i, 32-i are mainly arranged in the gas flow path of the thread groove pump section, but the deposit sensors 21-i, 32-i are The arrangement position of -i is not limited to this, and if the same effect is achieved, the arrangement position of -i is not limited to this, and if the same effect is achieved, it can be placed in the member that constitutes the gas flow path in the vacuum pump (for example, the upper end of a threaded spacer, supporting the stator blade 2). It may be any location on the inner wall surface of the ring, casing 1, base, stator column, exhaust port 9, etc.).

Furthermore, although the vacuum pumps according to the first and second embodiments are equipped with a thread groove pump section as an exhaust mechanism, they may be equipped with another type of exhaust mechanism (Siegbahn type, Goede type, etc.) instead. Even in that case, the deposit sensors 21-i, 32-i may be installed at any location in the gas flow path of the vacuum pump (including the gas flow path in the exhaust mechanism of the other type) where the same effect can be obtained. is placed.

The present invention is applicable to, for example, a vacuum pump.

1 Casing (part of an example of a stator)
2 Stator blades (part of an example of a stator)
7 Intake port 8 Thread groove 9 Exhaust port 11 Rotor 21-1 to 21-N, 32, 32-1 to 32-N Deposit sensor 41 Controller

Claims (6)

In vacuum pumps,
A flow path from a gas intake port to an exhaust port,
a deposit sensor disposed in the flow path upstream or downstream of a predetermined flow path position where the cause of operational trouble of the vacuum pump occurs;
The deposit sensor detects the presence or absence of the deposit at the position where the deposit sensor is placed, without detecting the thickness of the deposit at the position where the sediment sensor is placed,
The placement position of the deposit sensor is such that when the detection state of the deposit sensor changes from no deposit to presence of deposit, the thickness of the deposit at the predetermined flow path position suppresses the cause. be at a position where the specified thickness corresponds to the maintenance period to be performed;
A vacuum pump featuring further comprising a rotor and a stator,
2. The vacuum pump according to claim 1, wherein the deposit sensor is disposed on a wall of the flow path in the stator facing the rotor. Further equipped with a thread groove pump section,
The predetermined flow path position is an outlet portion of the thread groove pump part,
the deposit sensor is disposed on the bottom surface of the thread groove of the thread groove pump section in the flow path;
The vacuum pump according to claim 1, characterized in that: Also equipped with a controller,
The controller detects the maintenance time based on the detection state of the deposit sensor;
The vacuum pump according to any one of claims 1 to 3, characterized in that: In the flow path, a plurality of deposit sensors are provided upstream or downstream of a predetermined flow path position where the cause of operational trouble of the vacuum pump occurs,
Each of the plurality of deposit sensors detects the presence or absence of deposit at the position where the deposit sensor is placed,
(a) When the detection state from the plurality of deposit sensors changes from no deposit to presence of deposit, the thickness of the deposit at the predetermined channel position corresponds to the maintenance time; (b) detecting the maintenance time based on the detection state of the selected deposit sensor;
The vacuum pump according to claim 4, characterized in that: When the controller detects a sediment sensor whose detection state has changed from no sediment to presence of sediment among the plurality of sediment sensors, the controller determines the maintenance time at a notification level corresponding to the detected sediment sensor. 6. The vacuum pump according to claim 5, wherein a notification is provided.

Images