JP5524691B2 - Combined silencer and dry vacuum pump device - Google Patents

Description

  The present invention relates to a silencer for reducing noise generated when gas (gas) is exhausted from a dry vacuum pump, and more particularly, a compact silencer capable of silencing in a wide frequency band, and the silencer. The present invention relates to a dry vacuum pump device.

  In recent years, dry vacuum pump devices that can operate from atmospheric pressure and can easily obtain a clean vacuum environment have been used in a wide range of fields such as semiconductor manufacturing facilities. In particular, the manufacture of semiconductor devices consists of more than 300 processes, and the number of vacuum pumps used therein is very large. Therefore, the footprint saving of the vacuum pump device is very important for effective use of the site area in the factory. In particular, since a plurality of vacuum pump devices are often installed side by side according to the width of the vacuum pump device, it is important to reduce the width. Also, in a semiconductor device manufacturing apparatus, a pump may be installed inside the apparatus in order to reduce piping resistance between the apparatus and the vacuum pump, and downsizing of the vacuum pump is important.

  Further, in the dry vacuum pump device, noise is generated when gas is exhausted from the vacuum pump. In order to reduce this noise, it is necessary to provide a silencer on the exhaust side of the vacuum pump. There are two types of silencers, an expansion type and a resonance type. Inflatable silencers can mute (reduce) noise in a wide frequency range, but the frequency that can be silenced is inversely proportional to the length of the silencer, so a longer silencer is needed to mute noise in the lower frequency range. This becomes an obstacle to miniaturization of the dry vacuum pump device. In addition, the resonance type silencer is characterized in that it can be miniaturized and does not hinder the flow of the exhausted gas, but there is a problem that the frequency range in which the sound can be silenced is narrower than that of the expansion type silencer.

  As a technique related to a silencer of a conventional vacuum pump, there is one described in Patent Document 1. The silencer disclosed in Patent Document 1 is a system in which the gas discharged from the exhaust port of the vacuum pump passes through two or more large rooms and the first throttle port and the last large room between the large rooms. It is a silencer having a structure in which a second throttle port communicating with the inside is sequentially passed to reduce the noise of the gas and discharged into the outside air, and the opening amount of the first throttle port is set to the first throttle port. The width is adjusted in accordance with the pressure of the gas passing through or the amount of gas passing through.

JP 2001-289167 A

  The silencer disclosed in Patent Document 1 is adapted to the pressure of gas discharged from the exhaust port of a vacuum pump or a large-sized to small-sized vacuum pump operated under various operating conditions, and the amount of gas discharged, The opening amount of the first throttle port is adjusted to be large or small, and the noise of the gas exhausted from the exhaust port of the vacuum pump is efficiently reduced while suppressing the power loss of the vacuum pump. Therefore, the silencer disclosed in Patent Document 1 can effectively reduce noise in a wide frequency band from a low frequency region to a high frequency region that is generated when gas is exhausted from a vacuum pump, and can be downsized. It was not a silencer with a suitable structure.

  The present invention has been made in view of the above points, and includes a composite silencer that can be reduced in size and can effectively reduce noise in a wide frequency band from a low frequency region to a high frequency region, and the silencer. Another object of the present invention is to provide a dry vacuum pump device.

In order to solve the above problems, the present invention is a resonance-type silencer on the upstream side of the gas passage through which gas exhausted from the dry vacuum pump, the expansion silencer disposed downstream, co-sounding silencer A combined silencer for a vacuum pump, in which an expansion type silencer is integrated , the resonance type silencer has a resonance chamber, the resonance chamber communicates with the gas flow path through the resonance port, and the expansion type silencer is the first expansion. And a second expansion chamber, the first expansion chamber communicates with the gas flow path through the first throttle port, the second expansion chamber communicates with the first expansion chamber through the second throttle port, The first expansion chamber and the second expansion chamber communicate with each other through the third throttle port, and have different longitudinal dimensions.

Further, the present invention provides the above-described composite silencer, which includes a plate-shaped lid and a thick-plate-shaped silencer casing, a gas flow path recess having an upper opening serving as a gas flow path on one side of the silencer casing, and a resonance chamber. A resonance chamber recess that opens at the top, a first expansion chamber recess that opens at the top serving as the first expansion chamber, a second expansion chamber recess that opens at the top serving as the second expansion chamber, and an upper portion serving as the resonance port Forming a first aperture, a second aperture, a third aperture, and a first aperture, a second aperture, and a third aperture. The lid and the silencer casing are overlapped, and the openings of the resonance chamber recess, the resonance port recess, the first expansion chamber recess, the second expansion chamber recess, the first throttle port recess, the second throttle port recess, and the third throttle port recess are covered. It is characterized by obstruction by the body.

Further, the present invention includes one or a plurality of roots type dry vacuum pumps connected in series, an exhaust unit is provided on the exhaust side, and the composite type is provided in an exhaust gas flow path on the exhaust gas side of the exhaust unit. One of the silencers is in a dry vacuum pump device characterized in that the gas flow path is arranged to communicate with the exhaust gas flow path .

The present invention is also characterized in that, in the dry vacuum pump device, a check valve is provided in the exhaust gas flow path of the exhaust unit.

In the present invention, the resonance type silencer includes a resonance chamber, the resonance chamber communicates with the gas flow path through the resonance port, the expansion type silencer includes a first expansion chamber and a second expansion chamber, The second expansion chamber communicates with the first expansion chamber through the second constriction port, the second expansion chamber communicates with the first expansion chamber through the third constriction port, and communicates with the first expansion chamber. Since the longitudinal dimensions of the second expansion chamber are different from each other, it is possible to effectively mute (reduce) the noise in a wide frequency band generated by the dry vacuum pump .

Further, the present invention provides a gas flow path recess having an upper portion serving as a gas flow path on one side of the silencer casing, a resonance chamber recess opening an upper portion serving as a resonance chamber, and a first opening serving as a first expansion chamber. 1 expansion chamber recess, 2nd expansion chamber recess with an upper opening serving as a second expansion chamber, resonance opening recess with an upper opening serving as a resonance opening, first throttle opening, second throttle opening, and third throttle opening Forming a first throttle opening recess, a second throttle opening recess, and a third throttle opening recess that are open at the top, and overlapping the lid and the silencer casing to form a resonance chamber recess, a resonance port recess, and a first expansion chamber recess. Since the openings of the second expansion chamber recess, the first throttle port recess, the second throttle port recess, and the third throttle port recess are closed by the lid, the noise in the wide frequency band generated by the dry vacuum pump is effective. It can be muted a, silencer for small vacuum pump It can provide support. Further, the wall of the resonance chamber and the wall of the first expansion chamber are shared by one wall, and the walls of the first and second expansion chambers are shared by one wall, so that the silencer can be reduced in size. It was.

According to another aspect of the present invention, there is provided a roots-type dry vacuum pump, an exhaust unit is provided on the exhaust side thereof, and the composite silencer according to claim 1 or 2 is provided in the exhaust gas flow path on the exhaust gas side of the exhaust unit. because the flow path is arranged so as to communicate with the exhaust gas passage, and mute a wide have frequency band noise by the exhaust, maintains the installation environment of the apparatus serene, and since the silencer can be downsized can provide a dry vacuum pump apparatus can be made compact overall device.

It is a figure which shows the longitudinal cross-section of the dry vacuum pump apparatus equipped with the silencer which concerns on this invention. It is a figure which shows the cross-sectional structure of the dry vacuum pump apparatus equipped with the silencer which concerns on this invention. It is a figure which shows the structure of the silencer which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described in detail. First, a dry vacuum pump apparatus equipped with a silencer according to the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view showing the overall configuration of a tool-type positive displacement dry vacuum pump, and FIG. 2 is a sectional view taken along line AA in FIG. In the dry vacuum pump, a pair of five-stage root-type rotors 12a, 12b, 12c, 12d, and 12e are fixed to two rotating shafts 11a and 11b, respectively. The rotary shafts 11a and 11b are rotatably supported by bearings 20 and 21, respectively. In the following description, the pair of rotors 12a, 12b, 12c, 12d, and 12e are collectively referred to as rotors 12 and 12 as appropriate.

  Minute gaps are formed between the rotors 12 and 12 and between the rotors 12 and 12 and the inner peripheral surface of the rotor casing 14, and the rotors 12 and 12 are not centered on the respective rotation shafts 11a and 11b. It is designed to rotate by contact. Rotor chambers 13a, 13b, 13c, 13d, and 13e that accommodate the rotors 12a, 12b, 12c, 12d, and 12e, respectively, and transfer gas, respectively, have one rotor casing 14 in series along the two rotation shafts 11a and 11b. Is placed inside. A cover member (not shown) is attached to the upper surface of the rotor casing 14. A suction port 17 is formed in the upper part of the rotor casing 14, and the suction port 17 communicates with the first-stage rotor chamber 13 a. A first side casing 26 is fixed to the discharge port side surface of the rotor casing 14, and a bearing casing 23 is fixed to the side surface of the side casing 26. In the side casing 26, a discharge port 18 communicating with the rotor chamber 13e at the final stage is formed. As will be described later in detail, the discharge port 18 opens to the atmosphere through a check valve, an overcompression prevention valve, and a silencer.

  As shown in FIG. 1, a motor (for example, a brushless DC motor) 22 is disposed on the left side of the bearing 20 in the drawing. That is, a motor rotor 22a (only one motor rotor is shown in FIG. 3) is fixed to one end of the rotating shafts 11a and 11b, and a motor stator 22b is disposed around the motor rotor 22a. The motor 22 is supplied with variable frequency power by a power supply device such as an inverter device (not shown), and controls the rotation speed of the vacuum pump including soft start. The motor 22 is disposed inside the motor casing 24. When a brushless DC motor is adopted as the motor 22, the rotors 12 and 12 are synchronously reversed by the brushless DC motor 22 via the rotating shafts 11a and 11b. The timing gear 29 and the discharge-side bearing 21 are accommodated in a bearing casing 23 at the other end of the rotary shafts 11a and 11b, respectively. The bearings 20 and 21 are respectively held by bearing cases 40 and 41, and these bearing cases 40 and 41 are accommodated in the motor casing 24 and the bearing casing 23, respectively.

  In each of the rotor chambers 13a to 13f, the gas confined between the rotors 12 and 12 fixed to the two rotating shafts 11a and 11b and the inner peripheral surface of the rotor casing 14 is transferred from the suction side to the discharge side. Is done. The rotor casing 14 is a double casing, and gas flow paths 15a, 15b, 15c, 15d, and 15e are provided between the inner and outer peripheral walls constituting the double casing. The discharge side of the rotor chamber 13a and the suction side of the rotor chamber 13b at the next stage communicate with each other by a gas flow path 15a, and the gas compressed by the rotor 12a in the rotor chamber 13a passes through the gas flow path 15a and the rotor chamber 13b. It is transferred to the suction side. In this way, the gas compressed by the rotors 12, 12 of each stage is sequentially transferred to the discharge side through the gas flow paths 15 a to 15 e and transferred to the discharge port 18.

  In the dry vacuum pump, the volume of the rotor chamber 13a at the suction side first stage is effective for a pump having a ratio of 9 or more with respect to the volume of the rotor chamber 13e at the discharge side last stage. That is, the ratio of the thickness Wa of the first stage rotor 12a to the thickness We of the last stage rotor 12e is 9 or more, and this ratio is the volume ratio between the first stage rotor chamber 13a and the last stage rotor 12e.

  In general, the volume of the rotor chamber at the first stage is determined by the pumping speed of the designed vacuum pump. For this reason, when designing a vacuum pump with a high exhaust speed, it is necessary to increase the volume of the first-stage rotor chamber. On the other hand, the volume of the rotor chamber at the final stage suppresses heat generation (compression heat) due to the pressure difference before and after the rotor chamber at the final stage and the power consumption of the motor that rotates the rotor against the pressure difference. It is necessary to make it smaller. However, if the volume of the rotor chamber at the final stage is reduced, the exhaust cannot be performed smoothly. in this way. Since there is a trade-off relationship between the volume ratio and the heat generation, it is determined whether to increase or decrease the volume ratio (compression ratio) depending on which point is important to design the vacuum pump.

  When a brushless DC motor is adopted as the motor 22, by controlling the rotational speed of the motor 22, the exhaust speed can be increased while the volume of the rotor chamber 13e at the final stage is reduced, and the heat generation and the motor power consumption are reduced. Can be suppressed. That is, as compared with a conventional vacuum pump using a normal motor, the volume ratio (compression ratio) can be increased while achieving the same exhaust speed, and the heat generation amount can be suppressed. Further, by using the brushless DC motor 22 as described above as a drive source for rotationally driving the two rotary shafts 11a and 11b, not only the efficiency as a motor is good, but also a large load fluctuation can be dealt with. It is also possible to cope with an increase in compression power at the time of startup.

  A bearing 21 is disposed in the vicinity of the discharge port 18 of the dry vacuum pump, and rotatably supports the rotary shafts 11a and 11b together with the bearing 20 on the suction side. The bearing 21 is accommodated in a bearing casing 23, and a side casing 26 is disposed between the bearing casing 23 and the rotor casing 14. An O-ring seal (seal part) (not shown) is disposed between the bearing casing 23 and the side casing 26, thereby sealing a minute gap between the bearing casing 23 and the side casing 26. Further, an O-ring seal (seal part) (not shown) is also disposed between the side casing 26 and the rotor casing 14, thereby sealing a minute gap between the side casing 26 and the rotor casing 14. The bearing 20 is accommodated in a motor casing 24, and a second side casing 30 is disposed between the motor casing 24 and the rotor casing 14. An O-ring seal (seal part) (not shown) is disposed between the side casing 30 and the rotor casing 14. Further, an O-ring seal (seal part) (not shown) is disposed between the side casing 30 and the motor casing 24.

  In the dry vacuum pump having the above configuration, when the motor 22 is started and the rotating shafts 11a and 11b are rotated, the rotors 12a, 12b, 12c, 12d, and 12e rotate, and the gas sucked from the suction port 17 is the rotor chamber 13a. , 13b, 13c, 13d, and 13e, compressed by the rotors 12a, 12b, 12c, 12d, and 12e, sequentially transferred to the discharge side through the gas flow paths 15a to 15e, and discharged from the discharge port 18 to the atmospheric compression region Is done. An exhaust unit 50 is connected to the discharge port 18, and the gas discharged from the discharge port 18 is discharged through the exhaust unit 50. The exhaust unit 50 is provided with a final stage check valve 51, a second stage outlet check valve 52, and a silencer 53 having a configuration described in detail later. The second-stage outlet check valve 52 is a pressure relief hole provided to release the gas compressed in the dry vacuum pump above the atmospheric pressure into the outside air and to reduce the power loss of the dry vacuum pump. This is a check valve provided (not shown).

  The gas that has passed through the final-stage check valve 51 and the second-stage outlet check valve 52 of the exhaust unit 50 passes through the silencer 53, is reduced in noise, and is discharged to the outside. FIG. 3 is a diagram showing the configuration of the silencer 53. FIG. 3A is a view showing a side cross-sectional configuration of the silencer, and FIG. 3B is a cross-sectional view taken along the line AA. The silencer 53 is a combined silencer in which a resonance type silencer 53-1 and an expansion type silencer 53-2 are integrally formed. The resonance type silencer 53-1 and the expansion type silencer 53-2 are provided in communication with a gas flow path 61 that communicates with a gas flow path (not shown) of the exhaust unit 50, and the resonance type silencer 53-1 is located upstream. In addition, the expansion type silencer 53-2 is arranged on the downstream side.

  The silencer 53 includes a thick plate-like silencer casing 60 and a lid 69. The silencer casing 60 has a groove-shaped gas passage 61 having an open upper portion communicating with a gas passage (not shown) of the exhaust unit 50 on one side, and an upper portion constituting the resonance type silencer 53-1. A concave resonance chamber 62, a concave first expansion chamber 63 having an upper opening that constitutes the expansion silencer 53-2, and a second expansion chamber 64 are formed. Further, a groove-shaped resonance port 65 having an upper opening communicating with the resonance chamber 62 and the gas flow path 61, a groove-shaped first throttle port 66 having an upper opening communicating with the first expansion chamber 63 and the gas flow path 61, A second throttle port 67 having an open upper portion communicating with the first expansion chamber 63 and the second expansion chamber 64 and a third throttle port 68 communicating with the second expansion chamber 64 and the outside are provided.

  The surface of the silencer casing 60 on which the gas flow path 61, the resonance chamber 62, the first expansion chamber 63, the second expansion chamber 64, and the like are formed is covered with a lid 69, so that the gas flow path 61 and the resonance chamber 62 are covered. The first expansion chamber 63 and the second expansion chamber 64 are spaces in which the upper opening is closed. The resonance chamber 62 and the first expansion chamber 63 whose upper opening is closed communicate with the gas flow path 61 through the resonance port 65, respectively, and the first expansion chamber 63 and the second expansion chamber 64 whose upper opening is closed are the second throttle. The second expansion chamber 64 communicates with the outside through the third throttle port 68.

  In the silencer 53, as described above, the resonance silencer 53-1 and the expansion silencer 53-2 are integrally formed in the thick plate-like silencer casing 60, and the opening is closed by the lid 69. Type silencer. Further, since the silencer 53 is constituted by the thick plate-like silencer casing 60 and the lid body 69, the silencer is flat and miniaturized. The noise of the gas flow flowing into the gas flow path 61 from the gas flow path of the exhaust unit 50 is silenced (reduced) by resonating with the natural frequency of the resonance type silencer 53-1 including the resonance port 65 and the resonance chamber 62. ) The gas flow that has passed through the resonance type silencer 53-1 flows into the first expansion chamber 63 through the first restrictor 66 and is expanded and silenced (reduced) in the first expansion chamber. By flowing into the second expansion chamber 64 through the second restricting port 67, the sound is expanded and silenced (reduced) in the second expansion chamber 64, and further flows out to the outside air through the third restricting port 68 to expand and silence ( Reduced).

  The resonance silencer 53-1 can be reduced in size and has a feature that the flow of gas flowing through the gas flow path 61 is not obstructed, but the frequency range of noise that can be silenced is narrower than that of the expansion type. In contrast, the expansion silencer 53-2 can mute noise in a wide frequency range, but the frequency that can be muffled is inversely proportional to the length of the silencer. Therefore, when silencing in the low frequency range, the silencer becomes longer. End up. Therefore, by reducing the noise in the low frequency region of the gas flow with the resonance type silencer 53-1, which can be reduced in size, the noise of the remaining high frequency region is silenced with the expansion type silencer 53-2 in which the length of the silencer is inversely proportional to the silencing frequency. Both the resonance type silencer 53-1 and the expansion type silencer 53-2 are reduced in size, and the entire silencer 53 can be reduced in size, and noise can be silenced (reduced) in a wide frequency band.

  Further, since the resonance type silencer 53-1 is provided on the upstream side of the gas flow path 61, the resonance type silencer 53-1 has a feature that does not disturb the flow of the gas flowing into the gas flow path 61. Even if such a complex silencer is provided on the gas discharge side of the gas flow path of the exhaust unit 50, it is possible to suppress the reduction of the gas discharge function of the exhaust unit 50 as much as possible.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Can be modified. For example, in the above example, a dry vacuum pump apparatus including one roots type positive displacement dry vacuum pump has been described as an example. However, a dry vacuum pump apparatus having a configuration including a plurality of dry vacuum pumps may naturally be used. It is. Further, the dry type vacuum pump is not limited to the roots type positive displacement vacuum pump.

  In the present invention, since the resonance type silencer is arranged upstream of the gas flow in the gas flow path and the expansion type silencer is arranged downstream, and the resonance type silencer and the expansion type silencer are integrally configured, Noise can be silenced and used as a small siren. Further, by adopting the silencer according to the present invention as the silencer of the dry vacuum pump, it is possible to reduce the size of the exhaust unit equipped with the silencer and reduce the noise in a wide frequency band. Available as

11a Rotating shaft 11b Rotating shaft 12 Rotor 12a-12e Rotor 13a-13e Rotor chamber 14 Rotor casing 15a-15e Gas flow path 17 Suction port 18 Discharge port 20 Bearing 22 Motor 22a Motor rotor 22b Motor stator 23 Bearing casing 24 Motor casing 26 Side casing 29 Timing gear 30 Side casing 40 Bearing case 41 Bearing case 50 Exhaust unit 53 Silencer 53-1 Resonance type silencer 53-2 Expansion type silencer 60 Silencer casing 61 Gas flow path 62 Resonance chamber 63 First expansion chamber 64 Second expansion chamber 65 Resonance port 66 First aperture 67 Second aperture 68 Third aperture 69 Lid

Claims (4)

The resonance-type silencer on the upstream side of the gas passage through which gas exhausted from the dry vacuum pump, the expansion silencer disposed downstream, for a vacuum pump constituting said expansion silencer and the resonance silencer together A combined silencer ,
The resonance type silencer includes a resonance chamber, and the resonance chamber communicates with the gas flow path through a resonance port.
The expansion silencer includes a first expansion chamber and a second expansion chamber, the first expansion chamber communicates with the gas flow path through a first throttle port, and the second expansion chamber passes through a second throttle port. The first expansion chamber communicates with the outside through the third throttle port,
A composite silencer, wherein the first expansion chamber and the second expansion chamber have different longitudinal dimensions . The composite silencer according to claim 1, wherein
It has a plate-like lid and a thick plate-like silencer casing,
The silencer casing has a gas channel recess that opens at the upper part that becomes the gas channel, a resonance chamber recess that opens at the upper part that becomes the resonance chamber, and a first expansion that opens at the upper part that becomes the first expansion chamber. A chamber recess, a second expansion chamber recess in which the upper portion serving as the second expansion chamber opens, a resonance port recess in which the upper portion serving as the resonance port opens, the first throttle port, the second throttle port, the first Forming a first aperture recess, a second aperture recess, and a third aperture recess, each of which has three apertures open at the top;
The lid and the silencer casing are overlaid, the resonance chamber recess, the resonance port recess, the first expansion chamber recess, the second expansion chamber recess, the first throttle port recess, the second throttle port recess, A composite silencer , wherein the opening of the third throttle opening recess is closed with the lid . The composite type according to claim 1 or 2, comprising one or a plurality of roots type dry vacuum pumps connected in series, an exhaust unit provided on the exhaust side, and an exhaust gas flow path on the exhaust gas side of the exhaust unit. A dry vacuum pump device, wherein a silencer is disposed such that the gas flow path communicates with the exhaust gas flow path . In the dry vacuum pump device according to claim 3,
A dry vacuum pump device comprising a check valve in an exhaust gas flow path of the exhaust unit .

Images