JPH0726625B2 - 2-stage screw vacuum pump - Google Patents
2-stage screw vacuum pumpInfo
- Publication number
- JPH0726625B2 JPH0726625B2 JP2401676A JP40167690A JPH0726625B2 JP H0726625 B2 JPH0726625 B2 JP H0726625B2 JP 2401676 A JP2401676 A JP 2401676A JP 40167690 A JP40167690 A JP 40167690A JP H0726625 B2 JPH0726625 B2 JP H0726625B2
- Authority
- JP
- Japan
- Prior art keywords
- pump
- stage
- stage pump
- screw vacuum
- vacuum pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
- F04C23/001—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids of similar working principle
Description
【０００１】[0001]
【産業上の利用分野】本発明は、平行な２軸の回りを互
いに噛み合って回転する一対の雄ロータ及び雌ロータ
と、これら両ロータを収め吸込口及び吐出口を備えたケ
ーシングとからなる前段ポンプと後段ポンプとを設け、
前段ポンプの吐出口と後段ポンプの吸込口とを中間通路
で連通した２段スクリュー真空ポンプに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front stage comprising a pair of male and female rotors that rotate by meshing with each other around two parallel axes, and a casing containing both rotors and having a suction port and a discharge port. A pump and a rear pump are provided,
The present invention relates to a two-stage screw vacuum pump in which a discharge port of a front stage pump and a suction port of a rear stage pump communicate with each other through an intermediate passage.
【０００２】[0002]
【従来の技術】先ず、図３を参照してスクリュー真空ポ
ンプを説明する。2. Description of the Related Art First, a screw vacuum pump will be described with reference to FIG.
【０００３】図において、主ケージング１と吐出ケーシ
ング２とで形成された空腔内には、雄スクリューロータ
７（雌スクリューロータは図示していない）が軸受５
ａ、５ｂにより回転自在に支持されており、軸シール６
ａ、６ｂにより軸受５ａ、５ｂの潤滑油からシールされ
ている。In the figure, a male screw rotor 7 (a female screw rotor is not shown) is provided in a bearing 5 in a cavity formed by a main casing 1 and a discharge casing 2.
The shaft seal 6 is rotatably supported by a and 5b.
The bearings 5a and 5b are sealed from the lubricating oil by a and 6b.
【０００４】その雄スクリューロータ７の一端には、両
ロータに微小隙間を設けて同時回転させるタイミングギ
ヤ１０が設けられ、このロータ７は図示しない増速装置
を介して図示しない電動機で高速回転されるようになっ
ている。A timing gear 10 is provided at one end of the male screw rotor 7 so that both rotors are rotated at the same time with a minute gap. The rotor 7 is rotated at a high speed by an electric motor (not shown) via a speed increasing device (not shown). It has become so.
【０００５】そして、吸込口８ａより吸込まれた気体
は、吸込ポート８ｂを通り両ロータで形成される歯溝空
間に吸込まれ、圧縮過程を経て吐出ポート９ｂを介し、
吐出口９ａから吐出されるようになっている。Then, the gas sucked from the suction port 8a passes through the suction port 8b and is sucked into the tooth space formed by the two rotors, passes through the compression process, and then passes through the discharge port 9b.
The liquid is discharged from the discharge port 9a.
【０００６】図４において、真空容器２１は前段ポンプ
２２の前段吸込口２７に接続され、その前段ポンプ２２
の前段吐出口２８は、中間通路２３により後段ポンプ２
４の後段吸込口２９に接続されている。In FIG. 4, the vacuum container 21 is connected to the pre-stage suction port 27 of the pre-stage pump 22, and the pre-stage pump 22 is connected to the pre-stage pump 22.
The front-stage discharge port 28 of the rear-stage pump 2 is provided by the intermediate passage 23.
4 is connected to the rear suction port 29.
【０００７】他方、駆動機２５の出力軸には、増速ギヤ
２６が設けられ、その増速ギヤ２６は、両ポンプＡ１、
Ａ２の雄ロータ７Ａ、７Ｂに連係されている。On the other hand, the output shaft of the drive unit 25 is provided with a speed increasing gear 26, and the speed increasing gear 26 includes both pumps A1,
It is linked to the A2 male rotors 7A and 7B.
【０００８】そして、真空容器２１内の気体は、前段ポ
ンプ２２、中間通路２３及び後段ポンプ２４を介し後段
吐出口３０から吐出され、真空容器２１内が高真空度に
維持されるようになっている。The gas in the vacuum container 21 is discharged from the rear-stage discharge port 30 through the front-stage pump 22, the intermediate passage 23 and the rear-stage pump 24 so that the inside of the vacuum container 21 is maintained at a high degree of vacuum. There is.
【０００９】このような２段スクリュー真空ポンプにお
いては、定常運転状態で前段ポンプ２２の吸込圧力は、
１０-2〜１０-3ｔｏｒｒに達し、中間通路２３内の圧力
（これは前段ポンプ２２の背圧であり、後段ポンプ２４
の吸込圧でもある）は、約１〜２０ｔｏｒｒであり、後
段ポンプ２４の吐出圧は、大気圧である。従って前段ポ
ンプ２２に吸込まれた気体の体積は、中間通路２３で
は、１／１００以下に圧縮されることになる。そのた
め、吸込圧の低い稀薄な気体を吸込む前段ポンプ２２
は、より多くの気体を取り込めるように、排気速度を大
きくし、他方、後段ポンプ２４は、小量の気体を排気す
ればよいことと、全体の小型化のために、前段ポンプ２
２の１５〜７０％の小さな排気速度にされている。In such a two-stage screw vacuum pump, the suction pressure of the pre-stage pump 22 in the steady operation state is
It reaches 10 -2 to 10 -3 torr and the pressure in the intermediate passage 23 (this is the back pressure of the front stage pump 22 and the rear stage pump 24
Is also about 1 to 20 torr, and the discharge pressure of the post-stage pump 24 is atmospheric pressure. Therefore, the volume of the gas sucked into the front stage pump 22 is compressed to 1/100 or less in the intermediate passage 23. Therefore, the pre-stage pump 22 that sucks a lean gas with a low suction pressure
Increases the exhaust speed so that more gas can be taken in. On the other hand, the post-stage pump 24 needs only to exhaust a small amount of gas, and in order to reduce the overall size, the front-stage pump 2
The pumping speed is as small as 15 to 70% of 2.
【００１０】したがって、１台の駆動機２５で、前後段
ポンプ２２、２４を大気圧から起動する場合には、前段
ポンプ２２から中間通路２３に排出される気体量より後
段ポンプ２４が排出する気体量が少ないので、中間通路
２３の圧力が大気圧以上に上昇し、前後段ポンプ２２、
２４とも駆動トルクが著しく増加する。また、そのとき
生じる圧縮熱により異常な温度上昇が起こり、各部材に
損傷が生じることがある。これは、前後段ポンプ２２、
２４をそれぞれ別個の駆動機で駆動する場合でも、同様
である。Therefore, when the front and rear stage pumps 22 and 24 are started from the atmospheric pressure by one driving machine 25, the gas discharged from the rear stage pump 24 is larger than the amount of gas discharged from the front stage pump 22 to the intermediate passage 23. Since the amount is small, the pressure in the intermediate passage 23 rises above atmospheric pressure, and the front and rear stage pumps 22,
24, the driving torque is remarkably increased. Further, the compression heat generated at that time causes an abnormal temperature rise, which may damage each member. This is the front and rear pump 22,
The same applies when 24 is driven by separate driving machines.
【００１１】[0011]
【発明が解決しようとする課題】これに対し、両ポンプ
２２、２４を別個の駆動機で駆動する場合には、先ず、
後段ポンプ２４を起動し、前段ポンプ２２の吸込圧と背
圧とが所定の圧力以後下になったのちに、前段ポンプ２
２を起動する方法が採られている。On the other hand, when driving both pumps 22 and 24 by separate driving machines, first,
The latter pump 24 is started, and after the suction pressure and back pressure of the former pump 22 become lower than a predetermined pressure, the former pump 2
The method of activating 2 is adopted.
【００１２】１台の駆動機２５で両ポンプ２２、２４を
駆動する場合には、両ポンプ２２、２４のタイミングを
ずらして起動するために、例えば前段ポンプ２２の動力
伝達手段として電磁クラッチなどを設け、タイミングを
計って電磁クラッチを接続している。したがって、構造
が複雑でコストが高く、大型になる。When driving both pumps 22 and 24 with one driving machine 25, an electromagnetic clutch or the like is used as the power transmission means of the preceding pump 22 in order to shift the timings of both pumps 22 and 24 and start them. It is provided and the electromagnetic clutch is connected by measuring the timing. Therefore, the structure is complicated, the cost is high, and the size is large.
【００１３】また、大気圧を吸入して中間通路２３の中
間圧が高くなったときに開く開閉弁を設け、中間通路２
３の大気を大気に開放するか、又は後段ポンプ２４の吐
出管に排出するようにしている技術が知られている（実
公平２−７２６８号公報、実公平２−２９２５９号公
報）。しかし、この公知技術では、排出先が大気圧なの
で、中間通路２３の圧力を大気圧以下にすることができ
ないので、駆動トルクの低減効果が充分ではない。Further, an open / close valve is provided which opens when the intermediate pressure in the intermediate passage 23 rises due to intake of atmospheric pressure.
There is known a technique in which the atmosphere of No. 3 is opened to the atmosphere or is discharged to the discharge pipe of the post-stage pump 24 (Japanese Utility Model Publication No. 2-7268, Japanese Utility Model Publication No. 2-29259). However, in this known technique, since the discharge destination is the atmospheric pressure, the pressure in the intermediate passage 23 cannot be made equal to or lower than the atmospheric pressure, so that the effect of reducing the drive torque is not sufficient.
【００１４】本発明は、上記した問題に鑑みてなされた
もので、中間圧の上昇を抑え、駆動トルクを低減する２
段スクリュー真空ポンプを提供することを目的としてい
る。The present invention has been made in view of the above problems, and suppresses an increase in intermediate pressure and reduces drive torque.
It is intended to provide a multi-stage screw vacuum pump.
【００１５】[0015]
【課題を解決するための手段】本発明の２段スクリュー
真空ポンプは、平行な２軸の回りを互いに噛み合って回
転する一対の雄ロータ及び雌ロータと、これら両ロータ
を収め吸込口及び吐出口を備えたケーシングとからなる
前段ポンプと後段ポンプとを設け、前段ポンプの吐出口
と後段ポンプの吸込口とを中間通路で連通した２段スク
リュー真空ポンプにおいて、後段ポンプの排気速度が前
段ポンプの排気速度よりも速くなるように構成されてい
る。SUMMARY OF THE INVENTION A two-stage screw vacuum pump according to the present invention comprises a pair of male and female rotors that rotate while meshing with each other around two parallel axes, and a suction port and a discharge port that house both rotors. In a two-stage screw vacuum pump in which a front-stage pump and a rear-stage pump each including a casing provided with are provided, and a discharge port of the front-stage pump and a suction port of the rear-stage pump communicate with each other through an intermediate passage, the exhaust speed of the rear-stage pump is It is configured to be faster than the exhaust speed.
【００１６】本発明の実施に際して、平行な２軸の回り
を互いに噛み合って回転する一対の雄ロータ及び雌ロー
タと、これら両ロータを収め吸込口及び吐出口を備えた
ケーシングとからなる前段ポンプと後段ポンプとを設
け、前段ポンプの吐出口と後段ポンプの吸込口とを中間
通路で連通した２段スクリュー真空ポンプにおいて、前
記後段ポンプのロータのサイズを前記前段ポンプのロー
タのサイズより大きく形成することが出来る。In carrying out the present invention, a pre-stage pump comprising a pair of male and female rotors that mesh with each other about two parallel axes to rotate, and a casing containing both rotors and having a suction port and a discharge port. In a two-stage screw vacuum pump in which a rear-stage pump is provided, and a discharge port of the front-stage pump and a suction port of the rear-stage pump communicate with each other through an intermediate passage, the size of the rotor of the rear-stage pump is made larger than the size of the rotor of the front-stage pump. You can
【００１７】また、平行な２軸の回りを互いに噛み合っ
て回転する一対の雄ロータ及び雌ロータと、これら両ロ
ータを収め吸込口及び吐出口を備えたケーシングとから
なる前段ポンプと後段ポンプとを設け、前段ポンプの吐
出口と後段ポンプの吸込口とを中間通路で連通した２段
スクリュー真空ポンプにおいて、前記後段ポンプのロー
タ回転ギヤの歯数を前記前段ポンプのロータ回転ギヤの
歯数より小さく形成することが出来る。Further, a pair of male and female rotors that mesh with each other about two parallel axes and rotate, and a front stage pump and a rear stage pump that are composed of a casing containing both rotors and having a suction port and a discharge port are provided. In a two-stage screw vacuum pump in which a discharge port of the front stage pump and a suction port of the rear stage pump communicate with each other through an intermediate passage, the number of teeth of the rotor rotary gear of the rear stage pump is smaller than the number of teeth of the rotor rotary gear of the front stage pump. Can be formed.
【００１８】[0018]
【作用】上記のように構成された２段スクリュー真空ポ
ンプにおいては、後段ポンプの排気速度が前段ポンプの
排気速度よりも速くなるように構成されている。したが
って、後段ポンプの吸込流体体積は前段ポンプの吐出流
体体積よりも常に大きくなる。そのため、起動時や定常
運転時に大気を吸込んでも、中間通路の圧力は大気圧以
下に抑えられる。その結果、駆動トルクが低減され、ま
た、圧縮熱による異常な温度上昇が防止される。In the two-stage screw vacuum pump constructed as described above, the evacuation speed of the latter-stage pump is higher than that of the former-stage pump. Therefore, the suction fluid volume of the latter stage pump is always larger than the discharge fluid volume of the former stage pump. Therefore, the pressure in the intermediate passage can be suppressed to the atmospheric pressure or lower even if the atmosphere is sucked in at the time of startup or steady operation. As a result, the driving torque is reduced and an abnormal temperature rise due to the compression heat is prevented.
【００１９】[0019]
【実施例】以下図面を参照して本発明の実施例を説明す
る。Embodiments of the present invention will be described below with reference to the drawings.
【００２０】なお、これらの図面において図４に対応す
る部分については、同じ符号を付して重複説明を省略す
る。In these drawings, the parts corresponding to those in FIG. 4 are designated by the same reference numerals and their duplicate description will be omitted.
【００２１】図１において、後段ポンプ２４Ａの雄ロー
タ７ｂ（雌ロータは図示していない）は、前段ポンプ２
２の雄ロータ７Ａ（雌ロータは図示していない）より大
径に形成されている。In FIG. 1, the male rotor 7b (female rotor is not shown) of the rear stage pump 24A is the front stage pump 2
The diameter is larger than that of the second male rotor 7A (female rotor is not shown).
【００２２】したがって、後段ポンプ２４Ａの吸込流体
体積は、前段ポンプ２２の吸込流体体積より常に大き
い。そのため、起動時や定常運転時に大気を吸込んで
も、中間通路２３の圧力は、大気圧以下に抑えられる。
その結果、駆動機２５の駆動トルクが低減され、また、
圧縮熱による異常な温度上昇が防止される。Therefore, the suction fluid volume of the rear stage pump 24A is always larger than the suction fluid volume of the front stage pump 22. Therefore, the pressure in the intermediate passage 23 can be suppressed to the atmospheric pressure or lower even if the atmosphere is sucked in at the time of startup or steady operation.
As a result, the drive torque of the drive machine 25 is reduced, and
Abnormal temperature rise due to heat of compression is prevented.
【００２３】図２は本発明の別な態様を示しており、増
速ギヤ２６Ａの後段ポンプ２４の増速比は、前段ポンプ
２２の増速比より大きく形成されている。すなわち被動
ギヤｂの歯数は、被動ギヤａの歯数より少なく形成され
ている。したがって、後段ポンプ２４の回転速度は、前
段ポンプ２２の回転速度より大きく、前記と同様な作用
効果がある。FIG. 2 shows another embodiment of the present invention, in which the speed increasing ratio of the rear stage pump 24 of the speed increasing gear 26A is made larger than the speed increasing ratio of the front stage pump 22. That is, the number of teeth of the driven gear b is smaller than that of the driven gear a. Therefore, the rotation speed of the rear-stage pump 24 is higher than the rotation speed of the front-stage pump 22, and the same effect as the above is obtained.
【００２４】[0024]
【発明の効果】本発明は、以上説明したように構成され
ているので、後段ポンプの排気速度を前段ポンプの排気
速度より速くして、後段ポンプの吸込流体体積を前段ポ
ンプの吐出流体体積よりも常に大きくすることにより、
中間通路の圧力を大気圧以下に抑え、駆動トルクを低減
し、それにより、圧縮熱による異常な温度上昇を防止す
ることができる。Since the present invention is configured as described above, the exhaust speed of the rear pump is made higher than the exhaust speed of the front pump so that the suction fluid volume of the rear pump is greater than the discharge fluid volume of the front pump. By always increasing
It is possible to suppress the pressure in the intermediate passage to be equal to or lower than the atmospheric pressure and reduce the driving torque, thereby preventing an abnormal temperature rise due to compression heat.
【図１】本発明の一態様を示す構成図。FIG. 1 is a configuration diagram illustrating one embodiment of the present invention.
【図２】本発明の別の態様を示す構成図。FIG. 2 is a configuration diagram showing another aspect of the present invention.
【図３】スクリュー真空ポンプを示す側断面図。FIG. 3 is a side sectional view showing a screw vacuum pump.
【図４】２段スクリュー真空ポンプを示す構成図。FIG. 4 is a configuration diagram showing a two-stage screw vacuum pump.
７Ａ、７Ｂ、７ｂ・・・雄ロータ ２１・・・真空容器 ２２・・・前段ポンプ ２３・・・中間通路 ２４、２４Ａ・・・後段ポンプ ２５・・・駆動機 ２６、２６Ａ・・・増速ギヤ ２７・・・前段吸込口 ２８・・・前段吐出口 ２９・・・後段吸込口 ３０・・・後段吐出口 7A, 7B, 7b ... Male rotor 21 ... Vacuum container 22 ... Pre-stage pump 23 ... Intermediate passage 24, 24A ... Post-stage pump 25 ... Drive machine 26, 26A ... Acceleration Gear 27 ... front stage suction port 28 ... front stage discharge port 29 ... rear stage suction port 30 ... rear stage discharge port
Claims (1)
転する一対の雄ロータ及び雌ロータと、これら両ロータ
を収め吸込口及び吐出口を備えたケーシングとからなる
前段ポンプと後段ポンプとを設け、前段ポンプの吐出口
と後段ポンプの吸込口とを中間通路で連通した２段スク
リュー真空ポンプにおいて、後段ポンプの排気速度が前
段ポンプの排気速度よりも速くなるように構成したこと
を特徴とする２段スクリュー真空ポンプ。1. A front-stage pump and a rear-stage pump each comprising a pair of male and female rotors that mesh with each other about two parallel axes and rotate, and a casing containing both rotors and having a suction port and a discharge port. In a two-stage screw vacuum pump in which the discharge port of the front-stage pump and the suction port of the rear-stage pump communicate with each other through an intermediate passage, the exhaust speed of the rear-stage pump is higher than the exhaust speed of the front-stage pump. A two-stage screw vacuum pump.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2401676A JPH0726625B2 (en) | 1990-12-12 | 1990-12-12 | 2-stage screw vacuum pump |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2401676A JPH0726625B2 (en) | 1990-12-12 | 1990-12-12 | 2-stage screw vacuum pump |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04314990A JPH04314990A (en) | 1992-11-06 |
| JPH0726625B2 true JPH0726625B2 (en) | 1995-03-29 |
Family
ID=18511513
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2401676A Expired - Fee Related JPH0726625B2 (en) | 1990-12-12 | 1990-12-12 | 2-stage screw vacuum pump |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0726625B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20040106695A (en) * | 2003-06-11 | 2004-12-18 | 이기춘 | Four-in pump |
| FR2869369B1 (en) * | 2004-04-21 | 2006-07-21 | Alcatel Sa | VACUUM PUMP MULTI-STAGE, AND PUMPING INSTALLATION COMPRISING SUCH A PUMP |
| DE102006050943B4 (en) * | 2006-10-28 | 2020-04-16 | Pfeiffer Vacuum Gmbh | Vacuum pump and method for operating the same |
| DE102014017075B4 (en) * | 2014-11-20 | 2017-11-02 | Itt Bornemann Gmbh | Device for conveying a medium |
-
1990
- 1990-12-12 JP JP2401676A patent/JPH0726625B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04314990A (en) | 1992-11-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |