JP2010127156A - Dry vacuum pump unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dry vacuum pump unit having a cooling fan for cooling air which can attenuate noise leaking to the outside through an air discharge port and air introduction port with an effective and compact structure. <P>SOLUTION: The unit consists of a vacuum pump module (a main pump 15 and a booster pump 16) which is accommodated in an outer case 29, an air introduction port 29a which introduces air for cooling from the outside of the outer case 29, and a cooling fan 40 which discharges air introduced and cooled inner equipment to the outside of the case 29 through the air discharge port 29b. A soundproofing hood 85 for changing a flow direction of discharged air discharged through the air discharge port 29b is mounted in an outside position of the air discharge port 29b facing thereto. A sound absorbing material 89 is provided to a face on a side facing the air discharge port 29b of the soundproofing hood 85. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a dry vacuum pump unit having a vacuum ultimate pressure of about 1 Pa.

  A vacuum pump having an exhaust capability with a vacuum ultimate pressure of about 1 Pa is used for applications such as sputtering devices, helium leak detectors, and analysis devices such as SEM. Also, vacuum pumps with the above exhaust capability are used as vacuum pumps for roughing high vacuum pumps such as turbo molecular pumps, and for the purpose of sucking gases such as water vapor, such as vacuum drying and vacuum bonding devices It has been.

  Among these types of vacuum pumps, as a vacuum pump with a relatively high pumping speed (1000 L / min or more) used in semiconductor manufacturing applications, etc., a conventional two-shaft volume transfer type dry vacuum such as a multi-stage roots type or a screw type has been used. A pump is in use. In addition, in order to obtain a vacuum exhaust performance with an ultimate vacuum pressure of 1 Pa or less and a higher exhaust speed, two pumps, a main pump and a booster pump, are connected in series to form one vacuum pump unit. Some are. The biaxial positive displacement dry vacuum pump does not use oil in the gas passage unlike the oil rotary pump, so there is no oil contamination, and non-contact operation is possible without using the tip seal like the scroll type dry vacuum pump. Since it is possible, there is no generation of particles due to wear of the chip seal, and it is suitable for use in semiconductor manufacturing.

  Patent Document 1 discloses a biaxial volume transfer type dry vacuum pump of this type. This biaxial capacity transfer type dry vacuum pump includes a main pump disposed on the external air pressure side and a booster pump disposed on the vacuum side. The booster pump and the main pump are connected in series, while a cooling fan is connected. By being attached, air cooling air is forcibly introduced from the outside into the exterior case, and heat generated from each of the pumps and the like is discharged to the outside.

However, the cooling mechanism of the dry vacuum pump shown in Patent Document 1 introduces air into an air cooling air inlet provided in the outer case and forcibly introduces the introduced air by a cooling fan. Therefore, there is a problem that the noise inside the dry vacuum pump leaks to the outside as it is together with the air discharged from the air discharge port, and a large noise is generated. Similarly, there is a problem that noise inside the dry vacuum pump leaks to the outside from the air introduction port and a large noise is generated.
JP 2007-231935 A

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a dry vacuum pump unit having a cooling fan for air cooling. An object of the present invention is to provide a dry vacuum pump unit that can be damped.

  The invention according to claim 1 of the present application includes a vacuum pump module housed in an exterior case, an air introduction port for introducing air for cooling from the outside of the exterior case, and an interior introduced through the air introduction port. A cooling fan that discharges air that has cooled the device from the air discharge port to the outside of the exterior case, and is discharged from the air discharge port at a position outside the air discharge port that faces the air discharge port. The dry vacuum pump unit is equipped with a soundproof hood that changes the direction of flow.

  The invention according to claim 2 of the present application is the dry vacuum pump unit according to claim 1, wherein the sound absorbing hood silences noise leaking from the air outlet to the surface of the soundproof hood facing the air outlet. It is in the dry vacuum pump unit characterized by attaching the material.

  The invention according to claim 3 of the present application includes a vacuum pump module housed in an outer case, an air inlet for introducing air for air cooling from the outside of the outer case, and an air inlet introduced from the air inlet. A cooling fan that discharges air that has cooled the device from the air outlet to the outside of the outer case, and is introduced to the outside of the air inlet facing the air inlet before being introduced into the air inlet. The dry vacuum pump unit is equipped with a soundproof hood that changes the direction of air flow.

  The invention according to claim 4 of the present application is the dry vacuum pump unit according to claim 3, wherein the sound absorbing hood silences noise leaking from the air inlet to the surface of the soundproof hood facing the air inlet. It is in the dry vacuum pump unit characterized by attaching the material.

  The invention according to claim 5 of the present application is the dry vacuum pump unit according to claim 3 or 4, wherein the soundproof hood is an operation panel for operating the dry vacuum pump unit. It is in.

  The invention according to claim 6 of the present application is the dry vacuum pump unit according to claim 3, 4 or 5, wherein the dry vacuum pump unit has a substantially horizontal upper surface and a side surface substantially drooping from the upper surface. A booster pump arranged on the vacuum side is installed on the upper surface of the pump installation table, and a main pump arranged on the external pressure side and connected in series with the booster pump is installed on the side of the pump installation table. The electrical equipment for driving the dry vacuum pump unit is located on the opposite side of the upper surface of the pump installation table where the booster pump is installed and on the opposite side of the side of the pump installation table where the main pump is installed. In addition, the pump mounting base and electrical equipment are placed on the heat sink and air for cooling the heat sink is passed below the heat sink. One opening is provided as a second air introduction port for introducing external air and the other opening is provided as a lead-out port for supplying the introduced air into the exterior case, and the second air introduction port is provided with the circulation portion. The dry vacuum pump unit is arranged at the lower portion of the front outer case where the electrical equipment is installed.

  According to the first aspect of the present invention, since the soundproof hood that changes the direction of the flow of the discharged air is attached to the outside position of the air discharge port, noise leaking outside from the air discharge port is generated between the soundproof hood and the outer case. After being reflected one or more times in between, it is emitted to the outside. For this reason, noise can be attenuated effectively. In addition, since the soundproof hood is simply installed so as to face the air discharge port, the structure is simple and it is not bulky, and the structure can be made compact.

  According to the second aspect of the present invention, since the sound absorbing material is attached to the reflection surface of the soundproof hood that reflects the noise, the noise can be attenuated more effectively.

  According to the third aspect of the present invention, since the soundproof hood that changes the direction of the flow of the introduced air is attached to the outside position of the air inlet, noise leaking outside from the air inlet is between the soundproof hood and the outer case. And is emitted to the outside after being reflected one or more times. For this reason, noise can be attenuated effectively. In addition, since the soundproof hood is simply installed so as to face the air inlet, the structure is simple and can be configured in a compact structure without being bulky.

  According to the fourth aspect of the invention, since the sound absorbing material is attached to the reflection surface of the soundproof hood where the noise is reflected, the noise can be attenuated more effectively.

  According to the invention described in claim 5, since the soundproof hood is also used as the operation panel, the dry vacuum pump unit can be configured more compactly.

  According to the sixth aspect of the present invention, since the second air introduction port is disposed at a position farthest from the main pump and the booster pump, noise generated from the main pump and the booster pump reaches the second air introduction port. It is difficult to prevent noise leakage from the second air inlet.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a schematic side view of a dry vacuum pump unit 1 according to an embodiment of the present invention, FIG. 2 is a front view of the dry vacuum pump unit 1 shown in FIG. 1 viewed from the left side, and FIG. It is a schematic diagram. As shown in FIG. 1, the dry vacuum pump unit 1 has a main pump 15 and a booster pump 16 attached to a pump installation base 60, and the electrical equipment 17 that drives the dry vacuum pump unit 1 and the pump installation base 60 are connected to a heat sink. The outer case 29 is mounted and fixed so as to cover and fix the above-mentioned members. In the following description, the surface shown in FIG. 2 (the surface on which the soundproof hood 80 described below is attached) is referred to as the front surface, and the opposite surface (the surface on which the soundproof hood 85 described below is attached) is referred to as the rear surface. To do.

  The main pump 15 and the booster pump 16 are pumps having the same structure, and both are connected in series. However, the main pump 15 and the booster pump 16 do not necessarily have the same structure. The two pumps 15 and 16 are volumetric transfer type biaxial screw pumps that do not have a compression process, and do not use a timing gear, but use a non-contact magnet coupling to synchronously invert the biaxial pump rotor. And a vacuum pump for transferring gas. The motors 15m and 16m for driving the vacuum pumps 15 and 16 are brushless DC motors in which permanent magnets are arranged on the motor rotor. The motors 15m and 16m are driven by variable speed motor drivers in the electrical equipment 17. Fins 15f and 16f are attached to the outer peripheral side surfaces of the main pump 15 and the booster pump 16 (including motors 15m and 16m), respectively. The main pump 15 and the booster pump 16 are collectively referred to as a vacuum pump module.

  The electrical equipment 17 is for electrically controlling the dry vacuum pump unit 1 to drive it. The motor driver includes a motor driver for the main pump 15 and a motor driver for the booster pump 16. The main pump 15 and the booster pump 16 are driven to rotate independently. Both motor drivers are supplied with, for example, 48V DC power from a common DC power supply (AC / DC converter), and each motor driver converts the DC power into a rectangular pulse waveform by PWM. Is supplied to the drive winding. For example, the rotational speed of the vacuum pump (main pump) 15 on the external air pressure side is set to about 13000 rpm, the rotational speed of the vacuum pump (booster pump) 16 on the vacuum side is set to 15000 to 21000 rpm, and the rotational speed of the booster pump 16 is set to the main pump. The rotation speed is higher than 15. Thus, by rotating the vacuum pumps 15 and 16 at a high speed, an ultimate vacuum pressure of 1 Pa or less can be obtained while being small. Here, “outside air pressure” means the pressure in the ambient atmosphere of the vacuum pump unit 1, and more specifically, the pressure in the exhaust side space communicating with the vacuum pump unit 1. Since the ultimate pressure power is about 240 to 300 W, the power consumption is low, and the electric power of the dry vacuum pump unit 1 can be sufficiently supplied by an ordinary single-phase AC power source. For this reason, this dry vacuum pump unit 1 can be used as a portable vacuum pump wherever a single-phase AC power source can be used.

  The main pump 15 and the booster pump 16 are pumps having the same structure, but by operating the booster pump 16 at a higher speed than the main pump 15, a vacuum that cannot be obtained at all by operating this type of vacuum pump. An ultimate vacuum of about 1 Pa or less (0.5 Pa in this embodiment) is obtained on the container side.

  The pump mounting base 60 is formed of a single member made of a material having good thermal conductivity (aluminum in this embodiment), and includes a substantially flat upper plate portion 60a and a top plate portion 60a. The column portion 60b attached to the lower surface is integrally formed. The upper surface of the upper plate portion 60a is substantially horizontal, and the booster pump 16 is attached thereto. The side surface of the support column 60b is a surface that substantially hangs down from the upper surface, and the main pump 15 is attached to one side surface (the surface facing the air discharge port 29b). Inside the pump mounting base 60, a communication passage 61 that communicates between the exhaust port 16 b of the booster pump 16 and the intake port 15 a of the main pump 15, an exhaust port 15 b of the main pump 15, and a check valve 32 described below (see FIG. 3) and a pressure release passage 62 for bypassing the main pump 15 and connecting the communication passage 61 and the exhaust pipe 39. The pressure release passage 62 is further connected to an exhaust pipe 39 communicating with outside air via a pressure release valve (check valve) 31 and a pipe 47. Therefore, when the pressure in the communication path 61 between the main pump 15 and the booster pump 16 is high, the pressure release valve (check valve) 31 opens and communicates with the outside air via the exhaust pipe 39. Here, the pressure release valve (check valve) 31 has a structure in which a valve body pressurized by a spring presses an elastic body such as an O-ring (rubber ring) to seal the flow path, and the communication path It opens only when the pressure in 61 becomes higher than the external pressure. The material of the pump mounting base 60 may be another material such as titanium or stainless steel.

  Thereby, when the vacuum vessel to be exhausted to which the suction pipe 34 is connected is exhausted from the external pressure, the exhaust speed of the booster pump 16 is higher than the exhaust speed of the main pump 15, and therefore the connection pipe between the booster pump 16 and the main pump 15. The gas inside is overcompressed, but this overcompressed gas can be released into the outside air by the pressure release valve (check valve) 31. Accordingly, the pressure release valve (check valve) 31 prevents gas overcompression and is safe, and at the same time increases the power required for exhausting when the vacuum vessel is at the external pressure (when the intake side pressure is equal to the external pressure). Can be prevented. Further, the operation of the main pump 15 can be continued while maintaining the exhaust speed of the booster pump 16 as it is, and a decrease in the exhaust flow rate at the start-up can be prevented, and a desired degree of vacuum can be reached in a short time.

  That is, when there is no pressure release valve (check valve) 31, in order to avoid overcompression of gas, first, the main pump is evacuated and the booster pump is started after the vacuum state is reached to some extent. The main pump was started while operating at a low rotational speed. In this case, since the exhaust speed at startup is mainly determined by the main pump, there is a problem that the exhaust flow rate is low and a certain amount of time is required to reach a predetermined degree of vacuum. By providing the pressure release valve 31, it is possible to directly exhaust the gas at the external pressure with a booster pump having a high exhaust speed, and it is possible to reach the required vacuum degree in a short time.

  Here, as an operating condition of the pressure release valve 31, when a differential pressure is generated between the upstream side and the downstream side, the valve is immediately closed, and when the differential pressure disappears, the valve is immediately opened. For this reason, when the intake side changes from the external pressure to the vacuum pressure, the valve is quickly closed and there is no loss of exhaust time. Further, during steady operation, the pressure release valve 31 is always closed, so that the exhaust sound of the booster pump 16 does not leak outside.

  On the other hand, a pressure release valve 32 (see FIG. 3; not shown in FIG. 1 because it is located on the back side of the pressure release valve 31) attached to an exhaust passage 63 connected to the exhaust port 15b of the main pump 15 is also a spring. Has a structure in which the pressure-pressed valve body presses the O-ring (rubber ring). As a result, when the inside of the vacuum vessel is in a steady operation state where the vacuum is evacuated, the pressure release valve 32 is almost closed, and the exhaust sound of the main pump 15 can be blocked from leaking to the outside. Even when the operation of the main pump 15 is stopped due to some abnormality, the pressure release valve 32 is closed, so that the vacuum state can be prevented from being broken.

  The heat radiating plate 21 is formed in a substantially rectangular flat plate shape, and an air circulation portion 23 including a through hole through which air for cooling the heat radiating plate passes is formed on the lower surface side of the heat radiating plate 21. The front end of the air circulation portion 23 (the end on the front side of the electrical equipment 17) is exposed near the lower portion of the front surface of the exterior case 29 (the surface on which the soundproof hood 80 described below is installed), and the opening thereof is It is an air introduction port (hereinafter referred to as “second air introduction port”) 23 a for introducing air. The rear end of the air circulation portion 23 (the side where the soundproof hood 85 described below is installed) serves as an air outlet 23 b that opens at the lower portion of the main pump 15. A large number of fins 23c hang from the lower surface of the heat sink 21 into the air circulation portion 23 and extend from the front toward the rear. On the upper surface of the heat radiating plate 21, the lower surface of the column portion 60 b of the pump installation base 60 and the lower surface of the electrical equipment 17 are fixed. At this time, the electrical equipment 17 is on the side opposite to the upper surface where the booster pump 16 of the pump installation table 60 is installed (the lower surface side of the upper plate portion 60a) and opposite to the side where the main pump 15 of the pump installation table 60 is installed. It is installed so as to be located on the surface side (opposite surface side to which the main pump 15 of the support column 60b is attached).

  The outer case 29 is box-shaped, and an air inlet (hereinafter referred to as “first air inlet”) 29a is provided near the upper portion of the front surface (the surface on which the second air inlet 23a is located). In addition, an air discharge port 29 b is provided in the vicinity of the upper portion of the rear surface of the outer case 29. A cooling fan 40 is installed at a position facing the air outlet 29 b in the outer case 29. The cooling fan 40 forcibly discharges air introduced from the first and second air introduction ports 29a and 23a and cooling the internal devices to the outside from the air discharge port 29b. The discharge port of the cooling fan 40 may be used as it is as the air discharge port 29b.

  A soundproof hood 80 is attached to a position facing the first air inlet 29a outside the outer case 29 so as to be parallel to the front surface of the outer case 29 with a predetermined gap from the first air inlet 29a. Yes. The soundproof hood 80 has an opening 81 on the lower side and is opened, and the other three sides have side walls bent toward the exterior case 29 so that air is mainly introduced from the opening 81. ing. A sound absorbing material 83 is attached to the surface (inner surface) of the soundproof hood 80 facing the first air introduction port 29a to mute noise leaking from the first air introduction port 29a to the outside. In this embodiment, the sound absorbing material 83 is formed by forming a sponge-like flexible material into a plate-like body having a predetermined thickness. However, other various materials and shapes may be used. The soundproof hood 80 is also an operation panel for operating the dry vacuum pump unit 1, and is provided with an operation button, a stop button, an alarm reset button, etc. on the outer surface, an LED lamp for displaying the power ON state, an integration An operation time display panel is provided. The soundproof hood 80 is electrically connected to the electrical equipment 17 by a lead wire or the like.

  A soundproof hood 85 is attached at a position facing the air discharge port 29b outside the outer case 29 so as to be parallel to the outer case 29 with a predetermined gap from the air discharge port 29b. Similarly to the soundproof hood 80, the soundproof hood 85 has an opening 87 on the lower side thereof and is opened, and all the other three sides have side walls bent toward the exterior case 29, so that the soundproof hood 85 is mainly formed from the opening 87. Air is configured to be discharged. A sound absorbing material 89 is attached to the surface (inner surface) of the soundproof hood 85 facing the air discharge port 29b to mute noise leaking from the air discharge port 29b to the outside. The sound absorbing material 89 is also configured by forming a sponge-like flexible material into a plate-like body having a predetermined thickness in this embodiment, but various other materials and shapes may be used.

  4 is a schematic longitudinal sectional view of the main pump 15, and FIG. 5 is a sectional view taken along the arrow VV of FIG. As shown in these drawings, the vacuum pump 15 is a vacuum pump that uses a pair of non-contact magnet couplings to synchronize and invert a pair of screw rotors and transfer gas without using a timing gear. This is a volume transfer type twin screw pump. In the present embodiment, since the main pump 15 and the booster pump 16 have the same configuration, only the main pump 15 will be described below.

  Two rotating shafts 51 a and 51 b are arranged in parallel inside the casing 50, and the rotating shafts 51 a and 51 b are supported by bearings 53. A right-handed screw rotor (pump rotor) 52a is fixed to the rotating shaft 51a, and a left-handed screw rotor (pump rotor) 52b is fixed to the rotating shaft 51b. A fluid passage 56 is formed between the screw rotors 52 a and 52 b and the inner surface of the casing 50, an intake port 15 a is provided at the upstream end of the fluid passage 56, and an exhaust port is provided at the downstream end of the fluid passage 56. 15b is provided. The screw rotors 52a and 52b are reversed in contact with each other while maintaining a slight clearance so that the gas sucked from the intake port 15a is transferred to the exhaust port 15b. In addition, as a screw rotor 52a, 52b, you may use a pair of screw rotor which has an axial cross-sectional shape which contacts only on a pitch line.

  A pair of magnet rotors 54, 54 having the same configuration are arranged at the shaft ends on the intake side of the rotation shafts 51a, 51b, respectively, and the rotation shafts 51a, 51b are driven in reverse as brushless DC motors. Synchronous reversal of the rotating shafts 51a and 51b is ensured. As shown in FIG. 5, each magnet rotor 54 has a ring-shaped magnet 54a around the outer periphery of a magnetic material yoke 54b. In the present embodiment, a magnet 54a magnetized in six poles is provided on the outer periphery of the magnet rotor 54, facing each other so that the different magnetic poles of the magnet rotors 54 and 54 attract each other, and maintaining a clearance C. Has been placed. The number of poles of the magnet rotor 54 is an even number such as 6, 8, 10, 12.

  The screw rotors 52a and 52b are synchronously rotated in opposite directions by the magnet coupling action of the magnet rotors 54 and 54. Thereby, the screw pump which can perform the stable biaxial synchronous inversion even if there is no gear is comprised. The absence of gear means that no lubricating oil is required, non-contact rotation including a two-shaft perfect synchronization mechanism is possible, and high speed operation of the screw pump is possible. That is, in the contact-type synchronization mechanism using the timing gear, the rotation speed is 6000 to 7000 rpm, but by using the magnet coupling, the synchronous inversion high-speed rotation of about 10000 to 30000 rpm can be stabilized as described above. As a result, even if the vacuum pump is made smaller, an improvement in exhaust performance such as a high degree of vacuum is achieved.

  A three-phase (U, V, W) motor stator 57 including an iron core 57a and a winding 57b is disposed in the vicinity of a part of the outer peripheral surface of each magnet rotor 54. The three-phase motor stator 57 is disposed on the side opposite to the side where the magnet rotors 54 are magnet-coupled with respect to the rotation axis. Thereby, the magnet coupling force that the magnet rotors 54 attract each other can be canceled by the attraction force acting on the magnet rotor 54 and the motor stator core 57a. By supplying a direct current having a required rectangular pulse waveform to the three-phase winding 57b, the two rotating shafts 51a and 51b can be synchronously inverted and driven at an arbitrary rotational speed.

  In the case of a positive displacement screw pump, the gas flows in the axial direction as the screw rotors 52a and 52b rotate. Therefore, as shown in FIG. 1, when the main pump 15 is installed vertically and the exhaust port 15 b is disposed below the intake port 15 a, the exhaust port 15 b is positioned at the lower end of the fluid passage 56. Therefore, the flow of water (condensed water or the like) into the casing 50 can be prevented by the action of gravity, and overload and corrosion of the main pump 15 can be prevented. Further, in this case, since the magnet rotor 54 and the motor stator 57 are located above the screw rotors 52a and 52b (above the fluid passage 56), even if water flows in from the exhaust port 15b, these parts are There is no contact with. As described above, the main pump 15 is arranged to have an angle with respect to the horizontal direction so that the exhaust port 15b is positioned below the intake port 15a. In the present embodiment, as an example, the screw rotor of the main pump 15 is provided. 52a and 52b are arranged substantially vertically.

  Next, an operation method of the vacuum pump unit 1 configured as described above will be described. First, when the operation button provided on the operation panel (soundproof hood) 80 is pressed to turn on the power, both the booster pump 16 and the main pump 15 are soft-started and exhausted. Eventually, the rotational speeds of the booster pump 16 and the main pump 15 reach the rotational speeds of the set steady operation, and the exhaust is continued. Since the exhaust speed of the booster pump 16 is higher than the exhaust speed of the main pump 15, the pressure in the communication path 61 increases and the load power of the booster pump 16 also increases. When the pressure in the communication path 61 becomes larger than the external air pressure around the vacuum pump unit 1, the pressure release valve 31 is opened, the pressure in the communication path 61 is released, and the load on the booster pump 16 is constant. Become.

  When the pressure in the vacuum vessel is lowered, the pressure in the communication passage 61 is also lowered, so that the pressure release valve 31 is closed. Further, the load on the booster pump 16 is also reduced. When the pressure in the vacuum vessel further decreases and the ultimate vacuum is reached, the pressure difference between the intake side and the exhaust side of the booster pump 16 is small (both the intake and exhaust sides are in a vacuum state), so the booster pump 16 is in a state close to no-load operation. become. On the other hand, in the main pump 15, since the pressure difference between the intake side and the exhaust side is large (the intake side is vacuum and the exhaust side is the external pressure), the load of the main pump 15 is close to the rated value. At this time, even when the main pump 15 is abnormally stopped, the pressure release valve 32 is momentarily closed, so that the vacuum in the vacuum vessel can be prevented from being broken. Thus, as a feature of the vacuum pump unit 1, it is possible to perform start-up and steady operation without a sensor without detecting pressure and flow rate.

  On the other hand, when the power is turned on, the operation of the cooling fan 40 is started, air is introduced from the first and second air introduction ports 29a and 23a, and the dry vacuum pump unit 1 is shown by the arrows in FIGS. Flows across the interior space. That is, the cooling air sucked from the opening 81 at the lower end side of the soundproof hood 80 is sucked upward through the gap between the soundproof hood 80 and the outer case 29, and the air flow is substantially horizontal. The air is introduced into the exterior case 29 through the first air introduction port 29a. The introduced air mainly cools the booster pump 16 (including the motor 16m) and the motor 15m of the main pump 15, and then is discharged from the air outlet 29b of the outer case 29 through the cooling fan 40. On the other hand, the cooling air sucked from the second air introduction port 23a cools the heat sink 21 when passing through the air circulation part 23, and the electrical equipment 17 attached to the heat sink 21 and the main pump 15 and the pump mounting base 60 to which the booster pump 16 is attached are cooled. As a result, the electrical equipment 17 that generates heat, the main pump 15 and the booster pump 16 are cooled. Further, the air discharged from the air outlet 23 b moves obliquely upward, and at that time, mainly after cooling the main pump 15, the air is discharged from the air outlet 29 b of the outer case 29 through the cooling fan 40. As described above, when the inside of the vacuum vessel reaches the ultimate vacuum, the load of the main pump 15 reaches the rated value and generates heat more than the booster pump 16. Therefore, the cooling of the main pump 15 by the air from the air circulation unit 23 is It is valid. Then, the air discharged from the air discharge port 29b is discharged from the opening 87 on the lower end side of the soundproof hood 85 by changing the air flow substantially downward through the gap between the soundproof hood 85 and the outer case 29 from the horizontal direction. The

  As described above, the dry vacuum pump unit 1 cools the heat generated from the various internal components by air cooling. Therefore, the exterior case 29 has the first and second air inlets 29a and 23a and the air outlet 29b. I need it. For this reason, noise generated from the main pump 15, the booster pump 16, the cooling fan 40, etc. also leaks to the outside from the first and second air introduction ports 29a, 23a and the air discharge port 29b.

  Therefore, in this dry vacuum pump unit 1, the direction of the flow of the discharged air discharged from the air discharge port 29b is changed (from a substantially horizontal direction to a vertical direction) by the soundproof hood 85 installed outside the air discharge port 29b. The noise leaking outside from the air discharge port 29b is reflected one or more times between the soundproof hood 85 and the outer case 29 (part of the reflected noise returns into the outer case 29) and then released to the outside. Thus, the noise is effectively attenuated. Further, since the soundproof hood 85 is only installed so as to face the air discharge port 29b, the structure is simple and it is not bulky, and the structure can be made compact.

  Similarly, in the first air introduction port 29a, the flow direction of the introduced air before being introduced into the first air introduction port 29a is changed by the soundproof hood 80 installed outside the first air introduction port 29a (substantially). The noise leaking from the first air inlet 29a to the outside is reflected one or more times between the soundproof hood 80 and the outer case 29 (part of the reflected noise is reflected in the outer case 29). The sound is discharged to the outside after being returned), thereby effectively attenuating the noise. In addition, since the soundproof hood 85 is only installed so as to face the first air introduction port 29a, the structure is simple and can be configured in a compact structure without being bulky. In particular, since the soundproof hood 80 also serves as an operation panel, the dry vacuum pump unit 1 can be configured more compactly.

  Furthermore, since the sound absorbing materials 83 and 89 are attached to the reflection surfaces where the noise of the soundproof hoods 80 and 85 is reflected, the noise can be absorbed and attenuated more effectively.

  On the other hand, the electrical equipment 17 is on the opposite side of the upper surface of the upper plate portion 60a where the booster pump 16 of the pump installation table 60 is installed, and on the opposite side of the side surface of the column portion 60b where the main pump 15 of the pump installation table 60 is installed. The second air inlet 23 a is disposed at the lower part of the outer case 29 in front of the electrical equipment 17. That is, since the second air introduction port 23a is disposed at a position farthest from the main pump 15 and the booster pump 16, noise generated from the main pump 15 and the booster pump 16 reaches the second air introduction port 23a. This makes it difficult to prevent noise leakage from the second air inlet 23a.

  Although the embodiments of the present invention have been described above, 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. Is possible. Note that any shape, structure, or material not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited. For example, in the above-described embodiment, an example in which a screw type vacuum pump is used has been described. Needless to say, the gist of the present invention can be similarly applied to other types of volume transfer type biaxial vacuum pumps such as a roots type. Moreover, in the said embodiment, a vacuum pump module is comprised by the two-stage vacuum pump of the main pump 15 arrange | positioned at the external pressure side, and the booster pump 16 arrange | positioned in the vacuum side and connected to the said main pump 15 in series. However, the vacuum pump module is not limited to this, and may be a vacuum pump module configured by a single stage or three or more stages of vacuum pumps.

1 is a schematic side view of a dry vacuum pump unit 1. FIG. It is the front view which looked at the dry vacuum pump unit 1 shown in FIG. 1 from the left side. 1 is a schematic diagram of a dry vacuum pump unit 1. FIG. 2 is a schematic longitudinal sectional view of a main pump 15. FIG. It is a VV arrow line view of FIG.

Explanation of symbols

1 Dry vacuum pump unit 15 Main pump (vacuum pump)
16 Booster pump (vacuum pump)
17 electrical equipment 21 heat sink 23 air circulation part 23a 2nd air inlet (air inlet)
23b Air outlet 29 Exterior case 29a First air inlet (air inlet)
29b Air outlet 40 Cooling fan 60 Pump installation base 60a Upper plate part 60b Strut part 80 Soundproof hood 81 Opening 83 Sound absorbing material 85 Soundproofing hood 87 Opening 89 Sound absorbing material

Claims (6)

A vacuum pump module housed in an exterior case, an air introduction port for introducing air for air cooling from the outside of the exterior case, and air introduced from the air introduction port to cool the internal equipment from the air discharge port A cooling fan that is discharged to the outside of the outer case,
A dry vacuum pump unit comprising a soundproof hood for changing the direction of the flow of discharged air discharged from the air discharge port at a position outside the air discharge port facing the air discharge port. In the dry vacuum pump unit according to claim 1,
A dry vacuum pump unit characterized in that a sound absorbing material that silences noise leaking from the air discharge port to the outside is attached to the surface of the soundproof hood facing the air discharge port. A vacuum pump module housed in an exterior case, an air introduction port for introducing air for air cooling from the outside of the exterior case, and air introduced from the air introduction port to cool internal devices from an air discharge port A cooling fan that is discharged to the outside of the outer case,
A dry vacuum pump unit characterized in that a soundproof hood for changing the direction of the flow of introduced air before being introduced into the air introduction port is attached to an outer position of the air introduction port facing the air introduction port. In the dry vacuum pump unit according to claim 3,
A dry vacuum pump unit characterized in that a sound absorbing material that silences noise leaking from the air inlet to the outside is attached to the surface of the soundproof hood facing the air inlet. In the dry vacuum pump unit according to claim 3 or 4,
The dry vacuum pump unit, wherein the soundproof hood is an operation panel for operating the dry vacuum pump unit. The dry vacuum pump unit according to claim 3, 4 or 5,
The dry vacuum pump unit includes a pump mounting base having a substantially horizontal upper surface and a side surface substantially depending from the upper surface,
A booster pump arranged on the vacuum side is installed on the upper surface of the pump installation table, and a main pump arranged on the external pressure side and connected in series with the booster pump is installed on the side surface of the pump installation table,
The electrical equipment for driving the dry vacuum pump unit is positioned on the opposite side of the upper surface of the pump installation table where the booster pump is installed, and on the opposite side of the side of the pump installation table where the main pump is installed. Installed in
Further, the pump installation base and the electrical equipment are mounted on the heat sink, and an air circulation part for passing air for cooling the heat sink is provided at the lower part of the heat sink to introduce external air into one opening. An air inlet, the other opening is an outlet for supplying the introduced air into the exterior case, and the second air inlet is disposed at the lower part of the front exterior case where the electrical equipment is installed. Dry vacuum pump unit.

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