【発明の詳細な説明】〔発明の利用分野〕本発明はスクリュ一式真空ポンプに係り、特に大気圧か
ら１０−’Ｔｏｒｒレベルの低・中真空領域に好適なオ
イルフリー真空ポンプに関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an integrated screw vacuum pump, and more particularly to an oil-free vacuum pump suitable for low to medium vacuum ranges from atmospheric pressure to 10-' Torr level.
従来より低・中真空領域では油回転ポンプ、ルーツ式の
メカニカルブースターポンプ、エゼクタポンプ、拡散ポ
ンプなど１種々の形式の真空ポンプが用いられていた。Conventionally, various types of vacuum pumps such as oil rotary pumps, Roots-type mechanical booster pumps, ejector pumps, and diffusion pumps have been used in low and medium vacuum regions.
従来の真空ポンプや真空系の問題点は。What are the problems with conventional vacuum pumps and vacuum systems?
（１）真空ポンプの作動圧力範囲が狭く、大気圧から１
０−’Ｔｏｒｒレベルまで一台の真空ポンプで排気する
ことができない。特に背圧が大気圧のもとて作動可能な
真空ポンプとしては油回転ポンプがほとんど唯一のもの
であり、その他のポンプは背圧がＩＱＴｏｒｒ以下でな
いと使用できない、このため（、ＶＤ炉などの半導体製
造装置で１０−’ 〜１０−’ Ｔｏｒｒの到達圧力を
達成しようとすると２段の油回転ポンプを用いるか、あ
るいは第１図に一例を示す如く油回転ポンプ２を粗引き
ポンプとして使い、これにメカニカルブースター３など
他のポンプを組合せて使わざるをえない、この場合、真
空槽１の圧力が高いときにはバルブ５を開はバルブ６．
７を閉じて油回転ポンプで排気を行ない、ついで槽内の
圧力がメカニカルブースター３の作動可能な１０Ｔｏｒ
ｒ以下に低下したところでバルブ５を閉じ、バルブ６．
７を開けてメカニカルブースターと油回転ポンプを直列
に作動させて排気を続ける。このように従来の真空ポン
プを使った真空系は複雑で高価であり、またバルブの開
閉な、とその操作がきわめて煩雑であった。(1) The operating pressure range of the vacuum pump is narrow, from atmospheric pressure to 1
It is not possible to evacuate to the 0-'Torr level with a single vacuum pump. In particular, oil rotary pumps are almost the only vacuum pumps that can operate with back pressure at atmospheric pressure, and other pumps cannot be used unless the back pressure is below IQTorr. In order to achieve an ultimate pressure of 10-' to 10-' Torr in semiconductor manufacturing equipment, a two-stage oil rotary pump is used, or an oil rotary pump 2 is used as a roughing pump, as shown in an example in FIG. This must be used in combination with another pump such as a mechanical booster 3. In this case, when the pressure in the vacuum chamber 1 is high, valve 5 will open and valve 6.
7 is closed and evacuated using an oil rotary pump, and then the pressure inside the tank is increased to 10 Tor, which is enough for mechanical booster 3 to operate.
When the temperature drops to below r, valve 5 is closed, and valve 6.
Open 7 and operate the mechanical booster and oil rotary pump in series to continue evacuation. As described above, conventional vacuum systems using vacuum pumps are complicated and expensive, and the operations such as opening and closing of valves are extremely complicated.
（２）油回転ポンプは作動室内が油で満たされているた
め、この油分子が逆流して真空度が低下したり真空系を
汚染する恐れがある。このため油回転ポンプと真空槽の
間にトラップ４を設は油分子が真空槽側へ入り込まない
ようにする必要があり、真空系がますます複雑になって
いた。(2) Since the working chamber of an oil rotary pump is filled with oil, there is a risk that the oil molecules may flow back, lowering the degree of vacuum or contaminating the vacuum system. For this reason, it is necessary to install a trap 4 between the oil rotary pump and the vacuum chamber to prevent oil molecules from entering the vacuum chamber, making the vacuum system increasingly complex.
声たＣＶＤ装置では水素化物などの反応性ガスを用いる
ためガス中の活性成分により真空ポンプの油が分解変質
するので、頻繁に油を交換する必要が生じ、メンテナン
スに多大の労力と費用を要している。Since CVD equipment uses reactive gases such as hydrides, the oil in the vacuum pump decomposes and deteriorates due to the active components in the gas, making it necessary to change the oil frequently and requiring a great deal of effort and expense for maintenance. are doing.
（発明の目的）本発明の目的は、１０− ’ Ｔｏｒｒ程度のレベルの
中真空を１段のポンプで達成できる真空ポンプを提供す
ることにある。(Object of the Invention) An object of the present invention is to provide a vacuum pump that can achieve a medium vacuum of about 10-' Torr with a single stage pump.
真空ポンプは、低圧側の気体を高圧側へ排出する点にお
いて、基本的に圧縮機と同一の作用をなす。オイルフリ
ー圧縮機として、第２図に示すスクリュー圧縮機がよく
知られている。A vacuum pump basically functions in the same way as a compressor in that it discharges gas from a low pressure side to a high pressure side. A screw compressor shown in FIG. 2 is well known as an oil-free compressor.
雄ロータ８と雌ロータ９は互いに噛み合いながら、主ケ
ーシング１０と吸入ケーシング１１内に設けられた円筒
ころ軸受１２，１３，１４，１５によって回転自在に支
持される。組合せアンギュラ玉軸受１６．１７は雄・雌
ロータの軸方向の位置決めとともに、ロータに作用する
スラスト荷重を支える。雄ロータ８、雌ロータ９は主ケ
ーシング１０との間に作動室２６を形成し、ロータの回
転とともにこの作動室の容積を減少させて気体を圧縮す
る。シャフトシール１Ｂ、１９，２０゜２１は軸受の潤
滑油が作動室内へ侵入するのを防ぐ、ロータの吐出側軸
端に取り付けられたタイミングギヤ２２，２３は、雄・
雌面ロータが互いに接触しないよう両ロータ間の隙間を
調整している。The male rotor 8 and the female rotor 9 are rotatably supported by cylindrical roller bearings 12, 13, 14, and 15 provided in the main casing 10 and the suction casing 11 while meshing with each other. The combination angular contact ball bearings 16 and 17 support the axial positioning of the male and female rotors as well as the thrust loads acting on the rotors. The male rotor 8 and the female rotor 9 form a working chamber 26 between them and the main casing 10, and as the rotors rotate, the volume of this working chamber is reduced to compress the gas. The shaft seals 1B, 19, 20° 21 prevent lubricating oil from the bearings from entering the working chamber, and the timing gears 22, 23 attached to the shaft end on the discharge side of the rotor are
The gap between both rotors is adjusted so that the female rotors do not come into contact with each other.
駆動側の雄ロータの吸入側軸端にはピニオン２４が取付
けられ、図示されていない増速ギヤで駆動−される、ま
た主ケーシング１０には冷却ジャケット２５を設け、ジ
ャケット内に冷却水を４１Ｉ！ｉｉＩさせる。−前述の如く、圧縮機と真空ポンプはその作用は基本的に
同じであるが、第２図のオイルフリース、クリユー圧縮
機を真空ポンプとして用いたときの、特性の一例を第３
図に示す、第３図で実線と破線は、それぞれの背圧を大
気圧（７６０Ｔｏｒｒ ）およびＩＴｏｒｒにしたとき
の排気速度曲線である。A pinion 24 is attached to the suction side shaft end of the male rotor on the drive side, and is driven by a speed increasing gear (not shown).The main casing 10 is provided with a cooling jacket 25, and cooling water is supplied into the jacket by 41I. ! iii. - As mentioned above, the functions of compressors and vacuum pumps are basically the same, but Figure 3 shows an example of the characteristics when the oil fleece compressor shown in Figure 2 is used as a vacuum pump.
The solid line and broken line in FIG. 3 are exhaust velocity curves when the back pressures are set to atmospheric pressure (760 Torr) and ITorr, respectively.
、このようにオイルフリースクリユー圧縮機は真空ポン
プとして利用することが可能であるが、従来のオイルフ
リー圧縮機をそのまま用いたのでは。In this way, it is possible to use an oil-free screw compressor as a vacuum pump, but it is not possible to use a conventional oil-free compressor as is.
第３図に示す如く一段では大気圧からたかだか１Ｔｏｒ
ｒレベルの到達圧力しか得られない。したがって従来技
術を用いて１０−４．Ｔｏｒｒレベルの到、達圧力を得
るためには、第３図の実線と破線のような排気速度特性
をもつポンプを組合せて２段にする必要があり、必然的
瞬真空ポンプの構造が複雑で高価にならざるをえない。As shown in Figure 3, in one stage, the pressure is at most 1 Torr from atmospheric pressure.
Only the ultimate pressure of r level can be obtained. Therefore, using the prior art, 10-4. In order to obtain a pressure that reaches the Torr level, it is necessary to combine two stages of pumps with pumping speed characteristics as shown by the solid line and broken line in Figure 3, and the structure of the instantaneous vacuum pump is inevitably complicated. It has to be expensive.
第４図（ａ）はスクリュー流体機械で雄ロータ２７と雌
ロータ２８が噛み合っている状態を、ロータの周方向に
展開して示したモデルである。なお第４図は雄ロータと
雌ロータの歯数がそれぞれ４枚と６枚の場合について示
してものであるが、本発明はこれ以外の歯数組合せにつ
いても有効であることは以下の説明から明らかである。FIG. 4(a) is a model showing a screw fluid machine in which the male rotor 27 and the female rotor 28 are engaged with each other, developed in the circumferential direction of the rotor. Although FIG. 4 shows the case where the number of teeth of the male rotor and the female rotor are 4 and 6, respectively, it will be understood from the following explanation that the present invention is also effective for other tooth number combinations. it is obvious.
また第４図（ｂ）は、雄ロータ２７と雌ロータ２８の噛
み合い状態の斜視図であり、雄ロータ２７は４枚、雌ロ
ータ２８は５枚の歯数組合せである。Further, FIG. 4(b) is a perspective view of the meshing state of the male rotor 27 and the female rotor 28, and the male rotor 27 has a combination of four teeth and the female rotor 28 has five teeth.
ロータを覆うケーシング２９はその軸方向の一端が気体
の吸入ポート３５として大きく開口しており１反対側に
は吐出ポー１−３６が設けられている。この両ポート以
外ではケーシング２９は微少、な隙間をもってロータ２
７，２８を覆い、ロータ゛とケーシングによりＶ字形の
作動室を形成する。A casing 29 covering the rotor has a large opening at one axial end as a gas suction port 35, and a discharge port 1-36 on the opposite side. Other than these two ports, the casing 29 has a small gap between the rotor 2
7 and 28, and the rotor and casing form a V-shaped working chamber.
ロータが回転すると両ロータの噛み合い部は吸入ポート
３５から吐出ポート３６へ向って移動するが、この際作
動室３０′はその容積を減少させ作動室内の気体を圧縮
する。一方作動室３１は容積一定であるので気体の圧縮
作用はなく、移送作用をなす。When the rotors rotate, the meshing portions of both rotors move from the suction port 35 to the discharge port 36, and at this time the working chamber 30' reduces its volume and compresses the gas within the working chamber. On the other hand, since the volume of the working chamber 31 is constant, there is no compressing action of the gas, but a transporting action.
なお図中吸入ポート３６と連通している各作動室は、ロ
ータの回転にとともにその容積を増大させ気体の吸入作
用をなす。In addition, each working chamber communicating with the suction port 36 in the figure increases its volume as the rotor rotates, and performs a gas suction action.
スクリュー流体機械を圧縮機として利用する場合には、
この移送部分は必要なく吸入部分と圧縮部分だけを利用
すればよいので、例えば第２図のオイルフリースクリユ
ー圧縮機では雄ロータの巻き角？。＝２５０°、雄ロー
タ径ＤＭに対する長さＬの割合をＬ／ＤＨ＝１．２５
にしている。幾何学的な考察から明らかなように、吸入
部分と圧縮部分を利用するにはロータの巻き角は３６０
’以下でよいので、一般にスクリュー圧縮機では９ｓ
”２００””３００’ 、Ｌ／ＤＨ＝１．０〜１．７
の範囲に選んでいる。When using a screw fluid machine as a compressor,
This transfer part is not necessary and only the suction part and compression part need to be used, so for example, in the oil-free screw compressor shown in Figure 2, the winding angle of the male rotor? . = 250°, the ratio of length L to male rotor diameter DM is L/DH = 1.25
I have to. As is clear from geometrical considerations, the wrap angle of the rotor must be 360 to utilize the suction and compression sections.
In general, screw compressors require less than 9 seconds.
"200""300', L/DH=1.0~1.7
is selected within the range of
第４図（ａ）、第４図（ｂ）で作動室３２は吐出ポート
３６を通して気体を吐出中であり、ここの圧力は吐出圧
力に等しく各作動室の中で最も圧力が高くなっている。In FIGS. 4(a) and 4(b), the working chamber 32 is discharging gas through the discharge port 36, and the pressure here is equal to the discharge pressure and is the highest among the working chambers. .
作動室３２からの気体の洩れはロータ外周およびロータ
端面とケーシングの間の隙間を通って隣りの作動室３０
へ洩れるものと、両ロータの噛み合い部Ｋを通って第４
図の表側から裏側へ、すなわち雄ロータ側の作動室３３
と雌ロータ側の作動室３４へ洩れるものがある。Gas leaks from the working chamber 32 through the outer periphery of the rotor and the gap between the rotor end face and the casing to the adjacent working chamber 30.
What leaks to the fourth rotor through the meshing part K of both rotors.
From the front side of the figure to the back side, that is, the working chamber 33 on the male rotor side
There is some leakage into the working chamber 34 on the female rotor side.
前述のようにスクリュー圧縮機ではロータの巻き角は３
６０”以下であるので、作動室３３と３４は直接吸入ポ
ートに連通しており、ロータ噛み合い部のシール効果の
良し悪しが圧縮機の性能を大きく左右する。ロータ外周
部については、吐出ポートと吸入ポートの間には幾つか
の（第４図（ａ）では雄ロータで４ケ、雌ロータで６ケ
、第４図（ｂ）では雄ロータ４ケ、雌ロータで５ケ）の
密閉部ができるので、ここからの気体の洩れは比較的小
さい。As mentioned above, in a screw compressor, the winding angle of the rotor is 3.
60" or less, the working chambers 33 and 34 are in direct communication with the suction port, and the quality of the sealing effect at the rotor meshing area greatly influences the performance of the compressor. Regarding the outer periphery of the rotor, the discharge port and There are several sealing parts between the suction ports (4 on the male rotor and 6 on the female rotor in Figure 4(a), 4 on the male rotor and 5 on the female rotor in Figure 4(b)). , so gas leakage from here is relatively small.
さて圧縮機と真空ポンプの作用は基本的には同じという
ことを前に述べたが、大きな違いが１つある。それは真
空域では気体の圧力レベルにより気体の性質が全く異な
ってくることである。Now, I mentioned earlier that the functions of compressors and vacuum pumps are basically the same, but there is one major difference. The reason is that in a vacuum region, the properties of the gas differ completely depending on the pressure level of the gas.
第５図は空気の主成分である窒素分子の平均自由行程と
圧力の関係を示したものである。圧力が低くなると分子
の平均自由行程は長くなり、ＩＴｏｒｒの圧力で約０．
０５閣となる。スクリュー真空ポンプの各部の隙間は圧
縮機の場合と同じく大略０．１〜０．０５ｍ程度である
ので、大気圧からＩＴｏｒｒレベルの圧力では気体分子
の平均自由行程は各部の隙間より小さく、これらの隙間
を洩れ°る気体の流れは圧縮機の場合と同じ粘性流とし
て取り扱うことができる。一方ＩＴｏｒｒ以下の圧力レ
ベルになると気体分子の平均自由行程が各部の隙間より
長くなり、気体の流れは中間流あるいは分子流になる。FIG. 5 shows the relationship between the mean free path of nitrogen molecules, which is the main component of air, and pressure. As the pressure decreases, the mean free path of molecules becomes longer, and at a pressure of ITorr, it becomes about 0.
It becomes the 05th cabinet. The gaps between each part of a screw vacuum pump are approximately 0.1 to 0.05 m, as in the case of a compressor, so at pressures from atmospheric pressure to ITorr level, the mean free path of gas molecules is smaller than the gaps between each part, and these The flow of gas leaking through the gap can be treated as a viscous flow similar to that in a compressor. On the other hand, when the pressure level is lower than ITorr, the mean free path of gas molecules becomes longer than the gaps between the parts, and the gas flow becomes an intermediate flow or a molecular flow.
このような領域では気体分子は各部の隙間から洩れにく
くなり、空間を飛び回っている気体分すを捕捉し移送す
るだけで十分なポンプ作用をなすことが可能である。そ
して第４図のＡ部の移送部分だけのロータを、両端の開
いたケーシング内で回転させ、吸入側から吐出側へ排気
すると、吐出側の背圧がＬＴｏｒｒのときほぼ第３図の
破線で示した排気曲線に近い特性をうろことができる。In such a region, gas molecules are less likely to leak through the gaps between the parts, and it is possible to achieve a sufficient pumping effect simply by capturing and transporting the gas molecules flying around in the space. Then, the rotor of only the transfer part in part A of Fig. 4 is rotated in a casing with both ends open, and exhaust is exhausted from the suction side to the discharge side. When the back pressure on the discharge side is L Torr, the rotor is approximately the same as the broken line in Fig. 3. It is possible to explore characteristics close to the exhaust curve shown.
そこで第４図でロータの巻き角を大きくシ？。So, in Figure 4, do you want to increase the winding angle of the rotor? .
＝６５０°とすると１作動室は吸入ポートと吐出ポート
の間に２ケ所のロータ噛み合い部をもつことになり、作
動室３２の圧力が大気圧のとき作動室３３と３４の圧力
をＩＴｏｒｒレベルに、さらに吸入ポート３８の圧力を
１０−’Ｔｏｒｒレベルにすることができ、単段の真空
ポンプで大気圧から１０− ’ Ｔｏｒｒレベルまでの
到達圧力を得ることが可能になる。= 650°, one working chamber will have two rotor meshing parts between the suction port and the discharge port, and when the pressure in the working chamber 32 is atmospheric pressure, the pressure in the working chambers 33 and 34 will be at the ITorr level. Further, the pressure at the suction port 38 can be set to the 10-' Torr level, making it possible to obtain an ultimate pressure from atmospheric pressure to the 10-' Torr level with a single-stage vacuum pump.
ロータの巻き角？Ｈが６．５０ｍ、より小さいとき、例
えば第４図に示した如＜９’ｘ＝５００”のときには、
雄ロータの作動室は直接吸入ポートと連通してしまうが
、このときは３８の部分を吸入ケーシングで覆う、こと
によりこの作動室が吸入ポートに直接連通すやのを防ぐ
ことができる。Rotor wrap angle? When H is smaller than 6.50 m, for example, when <9'x=500'' as shown in Fig. 4,
The working chamber of the male rotor would directly communicate with the suction port, but by covering the portion 38 with the suction casing, it is possible to prevent this working chamber from directly communicating with the suction port.
作動室３０の圧力は作動室３２より低いが作動室３３や
３４よりかなり高いので、こ、こから作動室３５へ洩れ
た気体が直接吸入ポートへ洩れないようにするには、第
４図の破線で示したところまでロータを長くするとよい
。The pressure in the working chamber 30 is lower than that of the working chamber 32, but considerably higher than that of the working chambers 33 and 34, so in order to prevent the gas leaking from this to the working chamber 35 from directly leaking to the suction port, the pressure shown in FIG. It is best to lengthen the rotor to the point indicated by the broken line.
このようにロータの巻き角を大きくし噛み合いの数を多
くすれば気体の洩れは少なくなり真空ポンプとしての特
性は良くなるが、ポンプは大きく高価なものとなり、ま
たロータの軸方向長さが長くなることシこより軸振動な
どの問題が生ずる。ロータの巻き角を少なくすると真空
ポンプは小形安価になるが、そのポンプ特性は劣ること
になる。In this way, increasing the winding angle of the rotor and increasing the number of engagements reduces gas leakage and improves the characteristics of a vacuum pump, but the pump becomes larger and more expensive, and the axial length of the rotor is longer. This causes problems such as shaft vibration. If the winding angle of the rotor is reduced, the vacuum pump will become smaller and cheaper, but the pump characteristics will be inferior.
このようにロータの巻き角？８、長さＬ／ＤＭやロータ
歯数は真空ポンプとしての特性、価格、寸法等を勘案し
て決められるが２本発明で第１に重要な点は、各作動室
は吸入ポートと吐出ボートとの間に２ケ所〜３ケ所の密
閉部を有することである。Is this the winding angle of the rotor? 8. The length L/DM and the number of rotor teeth are determined by taking into consideration the characteristics, price, dimensions, etc. of the vacuum pump, but 2. The first important point in the present invention is that each working chamber has a suction port and a discharge port. There are two to three sealed parts between the two.
具体的には、−１，吸入行程の作動室と、移送行程の作動室とを隔て
る第１の密閉部、移送行程の作動室と圧縮行程または、
吐出行程の作動室とを隔てる第２の密閉部を備え、第１
．２の密閉部はともに両ロータの噛合い部によって形成
される。Specifically, -1. A first sealed part that separates the working chamber of the suction stroke and the working chamber of the transfer stroke, the working chamber of the transfer stroke and the compression stroke, or
A second sealing part separating the working chamber from the discharge stroke;
．． Both of the two sealing parts are formed by the meshing parts of both rotors.
２、移送行程の作動室を形成する第１．第２の密閉部、
圧縮行程に入る直前の作動室を形成する第２、第３の密
閉部を備え、第１の密閉部は、ケーシングによって形成
され、第２，３の密閉部は、両ロータ同士の噛合い部に
よって形成されるようにしたことである。換言すれば、
ロータの任意の１つの溝に沿って、吸入、移送作用を行
なわせる移送用の作動室と圧縮、吐出作用を行なわせる
圧縮吐出用の作動室とを有し、この一対の作動室がロー
タの各溝に沿って形成される。そして、ロータの回転に
ともなって、一対の作動室は、軸方向に移動するので移
送室が途中において、圧縮、吐出用の作動室となり、こ
の作動室の吸入口寄りの位置に新たに移送用の作動室が
形成される。他の対の作動室も同様である。両ロータと
ケーシングによって形成される作動室が吸入口から遮断
されて、移送用の作動室を形成する時期は、圧縮、吐出
作用を行う作動室が、容積を縮少し始めるときから、吐
出口に連通ずる直前に達するまでの間に選定することが
望ましい。2. The first part forms the working chamber of the transfer stroke. a second seal,
It includes second and third sealed parts that form the working chamber just before entering the compression stroke, the first sealed part is formed by the casing, and the second and third sealed parts are formed by the meshing part between both rotors. This is done so that it is formed by In other words,
Along any one groove of the rotor, there is a transfer working chamber that performs suction and transfer actions, and a compression and discharge working chamber that performs compression and discharge actions. formed along each groove. As the rotor rotates, the pair of working chambers move in the axial direction, so the transfer chamber becomes a working chamber for compression and discharge in the middle, and a new chamber for transfer is placed near the suction port of this working chamber. A working chamber is formed. The same goes for the other pairs of working chambers. The working chamber formed by both rotors and the casing is cut off from the suction port to form the working chamber for transfer. The working chamber, which performs compression and discharge operations, begins to reduce its volume, and the working chamber is closed off from the suction port when it reaches the discharge port. It is desirable to select the time just before the connection is reached.
ロータの巻き角が３６０″以上のスクリュー形流体機械
として、第６図に示すねじポンプ（液体ポンプ）が知ら
れている。このねじポンプはロータの回転に伴って作動
室が吸入側から吐出側へ移送するが、流体に対しては移
送作用をなすのみで内部圧縮作用はない。本発明のスク
リュー真空ポンプは、その作動室が移送部と内部圧縮部
によって形成されているが、これが本発明で第２に重要
な点である。第７図は圧縮機あるいは真空ポンプにおい
て作動室の容積と圧力の関係を示したものである。圧力
Ｐ１の気体を圧力ＰＩ２に昇圧するとき、前記ねじポン
プの如き内部圧縮がなく移送作用のみの流体機械の圧縮
過程はＡ→Ｂ−ＤＣとなり、スクリュー圧縮機の如く内
部圧縮のある場合の過程はＡ−ＤＣとなる。熱力学でよ
く知られているように、圧力ＰＩ （容積Ｖｔ）の気体
を圧力Ｐ２に昇圧・排出するのに要する仕事量は面積Ｐ
、 ＡＢＰＩ２またはＰＩＡＣＰ１２によって表わされ
るので、内部圧縮をさせる方が必要な仕事量が少なくて
効率が良いことになる。A screw pump (liquid pump) shown in Fig. 6 is known as a screw type fluid machine with a rotor winding angle of 360'' or more.In this screw pump, the working chamber changes from the suction side to the discharge side as the rotor rotates. However, the screw vacuum pump of the present invention has a working chamber formed by a transfer section and an internal compression section; This is the second most important point. Figure 7 shows the relationship between the volume of the working chamber and the pressure in a compressor or vacuum pump. When increasing the pressure of gas at pressure P1 to pressure PI2, the screw pump The compression process in a fluid machine with no internal compression and only a transfer action, such as in a screw compressor, is A→B-DC, and the process in a case where there is internal compression, such as in a screw compressor, is A-DC.This is well known in thermodynamics. As shown, the amount of work required to raise and discharge gas at pressure PI (volume Vt) to pressure P2 is the area P.
, ABPI2 or PIACP12. Therefore, internal compression requires less work and is more efficient.
大気圧から１０−’Ｔｏｒｒまで引く真空ポンプの必要
仕事量を考えると、第８図に示す如く１０−’Ｔｏｒｒ
からＩ Ｔｏｒｒまで昇圧するのに要する仕事量は、Ｉ
Ｔｏｒｒがら７６０ Ｔｏｒｒまで昇圧するのに要する
仕事量と比較して熊視できるほど小さい。したがって１
０−’ＴｏｒｒがらＩＴｏｒｒの間は内部圧縮は必要な
いが、ＩＴｏｒｒがら７６０Ｔｏｒｒの昇圧部分では内
部圧縮を行なわないと必要仕事量が非常に大きくなり、
真空ポンプとして効率が悪くなってしまう。Considering the amount of work required for a vacuum pump to draw from atmospheric pressure to 10-'Torr, the pressure is 10-'Torr as shown in Fig.
The amount of work required to increase the pressure from I Torr to I Torr is
Compared to the amount of work required to raise the pressure from Torr to 760 Torr, it is so small that it can be compared to the amount of work required to raise the pressure from Torr to 760 Torr. Therefore 1
Internal compression is not necessary between 0-'Torr and ITorr, but the amount of work required will be extremely large if internal compression is not performed in the boost section from ITorr to 760Torr.
It becomes less efficient as a vacuum pump.
以下本発明の一実施例を第９図、第１０図および第１１
図により説明する。An embodiment of the present invention will be described below with reference to FIGS. 9, 10, and 11.
This will be explained using figures.
雄ロータ３９と雌ロータ４ｏは主ケーシング４１と吸入
ケーシング４２内の軸受４５，４６゜４７．４Ｂにより
回転自在に支えられている。ロータの吸入側６５は１０
−’Ｔｏｒｒレベルの低圧であり吐出側６６は大気圧に
なるため、ロータに作用するラジアル荷重は吸入側の方
がはるかに小さい、そこで吸入側の軸受４５，４６には
深みぞ玉受軸を用いラジアル荷重とスラスト荷重を支え
、吐出側の軸受４７，４８には円筒ころ軸受を用いてラ
ジアル荷重のみを支持する。ロータの軸端にはタイミン
グギヤ４９，５０を取り付け、雄・雌ロータが互いに接
触しないよう両ロータ間の隙間を調整する。軸受４５．
４６の潤滑は飛まつ給油により行ない、吸入カバ４３内
に溜った潤滑油５６をタイミングギヤによって跳ねかけ
る。一方軸受４７．４８の潤滑のため雄ロータ軸には円
板５１を取り付け、吐出カバ４４内の潤滑油５７を円板
５１により跳ねかける。シャフトシール５２゜５３．５
４，５５は軸受やタイミングギヤの潤滑油が作動室内へ
侵入するのを防いでいる。ロータの吐出側作動室６６と
吐出カバ４４内はほぼ大気圧になるので吐出側のシャフ
トシール５４，５５に作用する差圧は比較的小さいが、
吸入側作動室６５は１０−’Ｔｏｒｒ レベルの圧力と
なるため吸入カバ４３内を大気に開放すると吸入側シャ
フトシール５２，５３に作用する差圧が大きくなりシー
ルが難かしくなる。そこで吸入カバ４３内を排圧管５９
，６０によって低圧の差動室６７と連通させ、吸入カバ
４３内の圧力を下げてシャフトシール５２，５３に作用
する差圧を小さくしてシール効果を高めている。吸入カ
バ４３内は油の飛沫が充満しているので、この油が排圧
管５９．６０を通って作動室へ入るのを防ぐため吸入カ
バには飛沫分離室５８が設けられ、また排圧管にはオイ
ルトラップ６１が取付けられている。また万一排圧管を
通って油が作動室へ入った場合でも、この油が吸入ポー
ト６３側へ逆流しないようにするため、主ケーシング４
１の排圧口６２はロータの作動室６７が吸入ポート６３
から完全に閉じられた後の位置に開口されている。雄ロ
ータ３９の作動室６７は、この作動室が吸入ポート６３
を通過後吐出ポート６４と連通するまでの間に雌ロータ
４０と２ケ所の噛み合い部６８．６９を有し、同様に雌
ロータの作動室７０は雄ロータと２ケ所の噛み合い部７
１．６９を有する。The male rotor 39 and the female rotor 4o are rotatably supported by bearings 45, 46 degrees 47.4B in the main casing 41 and suction casing 42. The suction side 65 of the rotor is 10
-' Torr level low pressure and atmospheric pressure on the discharge side 66, so the radial load acting on the rotor is much smaller on the suction side. Therefore, deep groove ball bearings are used for the bearings 45 and 46 on the suction side. The bearings 47 and 48 on the discharge side are cylindrical roller bearings to support only the radial load. Timing gears 49 and 50 are attached to the shaft ends of the rotors, and the gap between the male and female rotors is adjusted so that they do not come into contact with each other. Bearing 45.
46 is lubricated by splash oil supply, and the lubricating oil 56 accumulated in the suction cover 43 is splashed by a timing gear. On the other hand, a disk 51 is attached to the male rotor shaft to lubricate the bearings 47 and 48, and the disk 51 splashes the lubricating oil 57 inside the discharge cover 44. Shaft seal 52°53.5
4 and 55 prevent lubricating oil from the bearings and timing gear from entering the working chamber. Since the pressure inside the discharge side working chamber 66 of the rotor and the discharge cover 44 is almost atmospheric, the differential pressure acting on the discharge side shaft seals 54 and 55 is relatively small.
Since the pressure in the suction side working chamber 65 is at the 10-' Torr level, if the inside of the suction cover 43 is opened to the atmosphere, the differential pressure acting on the suction side shaft seals 52 and 53 increases, making sealing difficult. Therefore, the inside of the suction cover 43 is connected to the exhaust pressure pipe 59.
, 60 communicate with a low-pressure differential chamber 67 to lower the pressure inside the suction cover 43 and reduce the differential pressure acting on the shaft seals 52 and 53, thereby enhancing the sealing effect. Since the inside of the suction cover 43 is filled with oil droplets, a droplet separation chamber 58 is provided in the suction cover to prevent this oil from entering the working chamber through the exhaust pressure pipe 59 and 60. An oil trap 61 is attached. In addition, even if oil enters the working chamber through the exhaust pressure pipe, the main casing 4
The exhaust pressure port 62 of 1 is the working chamber 67 of the rotor and the suction port 63
It is opened to the position after it is completely closed. The working chamber 67 of the male rotor 39 is connected to the suction port 63.
The working chamber 70 of the female rotor has two meshing parts 68 and 69 with the male rotor before it communicates with the discharge port 64.
It has a value of 1.69.
ロータの回転に伴い気体は吸入ポート６３からロータ歯
溝とケーシングによって形成される作動室に吸い込まれ
、吐出ポート６４から吐出される。As the rotor rotates, gas is sucked into the working chamber formed by the rotor tooth space and the casing through the suction port 63, and is discharged through the discharge port 64.
作動室６７．７０はロータの回転に伴い容積一定のまま
気体を移送するが、さらにロータが回転した位置にある
作動室７２，７３はロータの回転に伴いその容積を減少
させ気体を内部圧縮する。このため吐出側では気体の温
度が上昇するので、主ケーシング４１の吐出側には冷却
ジャケット７４ａ〜７４ｅを設け、このジャケット内に
冷却水を通しケーシングや圧縮気体を冷却する。The working chambers 67 and 70 transfer gas with a constant volume as the rotor rotates, but the working chambers 72 and 73 located at the position where the rotor rotates decrease their volume and internally compress the gas as the rotor rotates. . For this reason, the temperature of the gas increases on the discharge side, so cooling jackets 74a to 74e are provided on the discharge side of the main casing 41, and cooling water is passed through the jackets to cool the casing and the compressed gas.
第１１図は本発明の他の実施例であり、説明を簡単にす
るためロータ部分についてのみ示すが、ロータ以外の構
成は第９図、第１０図と同一である。真空ポンプの吸入
側では気体の比容積が大きく吐出側では小さいので、真
空ポンプの排気速度を大きくするには吸入・移送作用を
なす作動室の容積を大きく、圧縮作用をなす作動室の容
積は小さくした方がよい。第１１図で雄ロータ７５と雌
ロータ７６は、吸入・移送作用をなす部分７７゜７８と
、圧縮作用をなす部分７９．８０によって構成されてい
る。吸入・移送部７７．７８は圧縮部７９．８０と比べ
てロータのねじれ角？８゜Ｔｐが小さくＬ／Ｄが大きい
、したがって、第１１図のロータを用いた真空ポンプは
、第９図の真空ポンプと同じ大きさで、大きな排気速度
を得ることができる。FIG. 11 shows another embodiment of the present invention, and to simplify the explanation, only the rotor portion is shown, but the structure other than the rotor is the same as FIGS. 9 and 10. The specific volume of gas is large on the suction side of a vacuum pump and small on the discharge side, so in order to increase the pumping speed of a vacuum pump, the volume of the working chamber that performs suction and transfer actions is increased, and the volume of the working chamber that performs compression action is It's better to make it smaller. In FIG. 11, the male rotor 75 and the female rotor 76 are composed of portions 77 and 78 that perform suction and transfer functions, and portions 79 and 80 that perform compression functions. Is the torsion angle of the rotor in the suction/transfer section 77, 78 different from that in the compression section 79, 80? 8°Tp is small and L/D is large. Therefore, the vacuum pump using the rotor shown in FIG. 11 has the same size as the vacuum pump shown in FIG. 9, and can obtain a large pumping speed.
上記の各実施例では、密閉部が２〜３箇所のものにつき
述べたが、密閉部が３〜４箇所（両ロータの噛合部によ
る密閉部を常時２箇所）のもの、すなわちロータの任意
の１つの溝部に沿って、吐出口から吸入口に至る間に圧
縮、吐出用の作動室、この作動室と両ロータの噛合部に
よる密閉部を介して連なる移送用の作動室、さらにこの
移送用の作動室と両ロータの噛合部による密閉部を介し
て第２の移送用作動室を形成してもよい。In each of the above embodiments, the case where there are 2 to 3 sealed parts is described, but the case where there are 3 to 4 sealed parts (there are always 2 sealed parts by the meshing part of both rotors), that is, any part of the rotor Along one groove, from the discharge port to the suction port, there is a working chamber for compression and discharge, a working chamber for transfer that is connected to this working chamber via a sealed part formed by the meshing part of both rotors, and a working chamber for transfer. A second transfer working chamber may be formed through the working chamber and a sealed portion formed by the meshing portion of both rotors.
このように溝部１箇所について移送用の作動室が２室形
成する矢、ガス洩れが減少するのでさらに高い真空度を
得ることができる。In this way, since two working chambers for transfer are formed for one groove, gas leakage is reduced, and a higher degree of vacuum can be obtained.
以上のように、本発明の実施例によれば、オイルフリー
真空ポンプの排気特性が大幅に改善され、１台の真空ポ
ンプで効率良く大気圧から１０−４Ｔ Ｏｒｒレベルの
中真空領域までの広い作動範囲をカバーすることが可能
となる。As described above, according to the embodiments of the present invention, the exhaust characteristics of the oil-free vacuum pump are greatly improved, and one vacuum pump can efficiently operate in a wide range from atmospheric pressure to medium vacuum range of 10-4T Orr level. It becomes possible to cover the operating range.
また本発明に係る真空ポンプを使用することにより、従
来の油回転ポンプやメカニカルブースターなどを組合せ
て使った真空系と比べて構造が簡単で安価な真空系を構
成することができる。さらに真空系の構成が簡単になる
ことにより、バルブの切換えなど煩雑な操作が不要にな
り制御系を簡単で安価なものにすることができる。Furthermore, by using the vacuum pump according to the present invention, it is possible to construct a vacuum system that is simpler in structure and cheaper than a vacuum system that uses a combination of conventional oil rotary pumps, mechanical boosters, and the like. Furthermore, by simplifying the configuration of the vacuum system, complicated operations such as switching valves are no longer necessary, and the control system can be made simple and inexpensive.
以上詳細に述べたように本発明によれば、大気圧から１
０−’Ｔｏｒｒ程度レベルの中真空を１段のポンプで達
成できる真空ポンプを提供することができる。As described in detail above, according to the present invention, from atmospheric pressure to
It is possible to provide a vacuum pump that can achieve a medium vacuum of about 0-'Torr level with a single stage pump.
第１図は従来の真空排気系の一例の系統図、第２図はオ
イルフリースクリユー圧縮機の断面図、第３図は第２図
のオイルフリースクリユー圧縮機を真空ポンプに転用し
たときの排気速度の一例を示す曲線図、第４図（ａ）、
第４図（ｂ）、第５図、第７図、第８図は本発明の詳細
な説明図、第６図はねじポンプの概要説明図、第９図、
第１０図は本発明の一実施例であり、第９図は第１０図
のＢ−Ｂ断面図、第１０図は第９図のＡ−Ａ断面図、第
１１図は本発明の他の実施例の説明図である。２７・・・雄ロータのモデル、２８・・・雌ロータのモ
デル、２９・・・ケーシングのモデル、３９・・・雄ロ
ータ、４０・・・雌ロータ、４１・・・主ケーシング、
４２・・・吸入ケーシング、４５．４６・・・深みぞ玉
軸受、４７゜４８・・・円筒ころ軸受、４９．５０・・
・タイミングギヤ、５２，５３，５４，５５・・・シャ
フトシール、６３・・・吸入ボート、６４・・・吐出ポ
ート。代理人 弁理士 高橋明夫′ｆＪ １ 図石 ２ 目冨 ３ 図吸猛１ （Ｔｏｒｒ）第 ４ 図 （（１−）第 ４ 図 Ｃｂ）３￥Ｊ ５ 図今４９平均自山ｒＴｊ限（ｍｍン１図■７ 図（作動１容イ囁〕′ｆＪ ｇ 図Ｔ→冨 １／ 図１．事件の表示昭和５９ 年特許顕部７０８３０ 号２発明の名称 スクリュー真空ポンプ３、補正をする者・１１件との関係 特許出願人名 称 （５１０１株式会＞、１ 日 立 製 作 所
４、代 理 人（１）本願明細書第６ページ第５行［第４図」を「第４
図（ａ）」に訂正する。（２）同上第６ページ第７行ｒ本発明は、これ以外の歯
数組合せについても有効で 」をｒ本発明は、これ以外
の歯数組合せたとえば雄ロータが４枚、雌ロータが５枚
や、雄ロータが５枚、雌ロータが６枚の組合せについて
も有効で」に訂正する。（３）同上第６ページ第１１行「雌ロータ２８は５枚の
歯数組合せである。」を「雌ロータ２８は、５枚の歯数
組合せが１枚差の場合である。」に訂正する。（４）同上第８ページ第４行「第４図」を「第４図（ａ
）、（第４図（ｂ）も同様）」に訂正する。（５）同上第１０ページ第２行および第２０行「第４図
」を「第４図（ａ）」に訂正する。（６）第４図（ｂ）を添付の通り訂正する。Figure 1 is a system diagram of an example of a conventional vacuum evacuation system, Figure 2 is a cross-sectional view of an oil-free screw compressor, and Figure 3 is when the oil-free screw compressor shown in Figure 2 is converted into a vacuum pump. A curve diagram showing an example of the pumping speed of FIG. 4(a),
Fig. 4(b), Fig. 5, Fig. 7, and Fig. 8 are detailed explanatory diagrams of the present invention, Fig. 6 is a schematic explanatory diagram of the screw pump, Fig. 9,
FIG. 10 shows one embodiment of the present invention, FIG. 9 is a sectional view taken along line BB in FIG. 10, FIG. 10 is a sectional view taken along line AA in FIG. 9, and FIG. It is an explanatory diagram of an example. 27... Male rotor model, 28... Female rotor model, 29... Casing model, 39... Male rotor, 40... Female rotor, 41... Main casing,
42...Suction casing, 45.46...Deep groove ball bearing, 47°48...Cylindrical roller bearing, 49.50...
・Timing gear, 52, 53, 54, 55...Shaft seal, 63...Suction boat, 64...Discharge port. Agent Patent Attorney Akio Takahashi'fJ 1 Zuishi 2 Mekutomi 3 Figure 4 ((1-) Figure 4 Cb) 3 ¥J 5 Figure 49 Average self-mountain rTj limit (mm) 1 Diagram ■ 7 Diagram (Operation 1 Volume I Whisper) 'fJ g Diagram T → Tomi 1/ Diagram 1. Display of the incident 1982 Patent Kenbu No. 70830 2 Title of the invention Screw vacuum pump 3, person making the correction 11 Relationship to the matter Name of patent applicant (5101 Co., Ltd.>, 1 Hitachi, Ltd. 4, Agent (1) Changed “Figure 4” from page 6, line 5 [Figure 4] of the specification of the present application to “Figure 4”)
Figure (a)” has been corrected. (2) Same as above, page 6, line 7. The present invention is also effective for other combinations of the number of teeth. For example, the male rotor has 4 teeth and the female rotor has 5 teeth. It is also valid for a combination of 5 male rotors and 6 female rotors.'' (3) Same as above, page 6, line 11, "The female rotor 28 has a combination of five teeth." is corrected to "The female rotor 28 has a combination of five teeth with a difference of one tooth." do. (4) Same as above, page 8, line 4, “Figure 4” is changed to “Figure 4 (a)
), (the same applies to Figure 4(b))”. (5) ``Figure 4'' in the 2nd and 20th lines of page 10 of the same page is corrected to ``Figure 4 (a).'' (6) Correct Figure 4(b) as attached.
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59070830AJPH079239B2 (en) | 1984-04-11 | 1984-04-11 | Screw vacuum pump |
| DE8585101569TDE3573152D1 (en) | 1984-04-11 | 1985-02-13 | Screw type vacuum pump |
| US06/701,199US4714418A (en) | 1984-04-11 | 1985-02-13 | Screw type vacuum pump |
| EP85101569AEP0166851B1 (en) | 1984-04-11 | 1985-02-13 | Screw type vacuum pump |
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59070830AJPH079239B2 (en) | 1984-04-11 | 1984-04-11 | Screw vacuum pump |
| Publication Number | Publication Date |
|---|---|
| JPS60216089Atrue JPS60216089A (en) | 1985-10-29 |
| JPH079239B2 JPH079239B2 (en) | 1995-02-01 |
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59070830AExpired - LifetimeJPH079239B2 (en) | 1984-04-11 | 1984-04-11 | Screw vacuum pump |
| Country | Link |
|---|---|
| JP (1) | JPH079239B2 (en) |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62243982A (en)* | 1986-04-14 | 1987-10-24 | Hitachi Ltd | 2-stage vacuum pump and operating method thereof |
| JPS62291479A (en)* | 1986-06-12 | 1987-12-18 | Hitachi Ltd | Vacuum exhaust device |
| JPS631794A (en)* | 1986-06-20 | 1988-01-06 | Hitachi Ltd | Spray lubricating device for oil free screw vacuum pump |
| JPS6336086A (en)* | 1986-07-30 | 1988-02-16 | Taiko Kikai Kogyo Kk | Multi-stage screw type vacuum pump |
| JPS6336085A (en)* | 1986-07-30 | 1988-02-16 | Taiko Kikai Kogyo Kk | Screw type vacuum pump |
| JPS63109292A (en)* | 1986-10-27 | 1988-05-13 | Hitachi Ltd | Screw vacuum pump |
| JPS648039U (en)* | 1987-06-29 | 1989-01-17 | ||
| JPH0180688U (en)* | 1987-11-19 | 1989-05-30 | ||
| US5314320A (en)* | 1991-07-10 | 1994-05-24 | Ebara Corporation | Screw vacuum pump with a reduced starting load |
| US5374170A (en)* | 1991-07-10 | 1994-12-20 | Ebara Corporation | Screw vacuum pump |
| EP0697523A2 (en) | 1994-08-19 | 1996-02-21 | Diavac Limited | Screw fluid machine and screw gear used in the same |
| US6302641B1 (en) | 2000-01-07 | 2001-10-16 | Kashiyama Kougyou Industry Co., Ltd. | Multiple type vacuum pump |
| US6514035B2 (en) | 2000-01-07 | 2003-02-04 | Kashiyama Kougyou Industry Co., Ltd. | Multiple-type pump |
| JP2012533016A (en)* | 2009-07-10 | 2012-12-20 | ロブスキ・エッセ・ピ・ア | Dry screwdriver |
| US10738778B2 (en) | 2018-01-22 | 2020-08-11 | Kabushiki Kaisha Toyota Jidoshokki | Motor-driven roots pump |
| EP3597920A3 (en)* | 2014-04-25 | 2021-03-24 | Kaeser Kompressoren Se | Rotor pair for a compressor block of a screw machine |
| US10975867B2 (en) | 2015-10-30 | 2021-04-13 | Gardner Denver, Inc. | Complex screw rotors |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001207984A (en) | 1999-11-17 | 2001-08-03 | Teijin Seiki Co Ltd | Vacuum exhaust device |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55153881A (en)* | 1979-04-24 | 1980-12-01 | Anretsuto:Kk | Helical type double-axle rotary fluid pump |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55153881A (en)* | 1979-04-24 | 1980-12-01 | Anretsuto:Kk | Helical type double-axle rotary fluid pump |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62243982A (en)* | 1986-04-14 | 1987-10-24 | Hitachi Ltd | 2-stage vacuum pump and operating method thereof |
| JPS62291479A (en)* | 1986-06-12 | 1987-12-18 | Hitachi Ltd | Vacuum exhaust device |
| JPS631794A (en)* | 1986-06-20 | 1988-01-06 | Hitachi Ltd | Spray lubricating device for oil free screw vacuum pump |
| JPS6336086A (en)* | 1986-07-30 | 1988-02-16 | Taiko Kikai Kogyo Kk | Multi-stage screw type vacuum pump |
| JPS6336085A (en)* | 1986-07-30 | 1988-02-16 | Taiko Kikai Kogyo Kk | Screw type vacuum pump |
| JPS63109292A (en)* | 1986-10-27 | 1988-05-13 | Hitachi Ltd | Screw vacuum pump |
| JPS648039U (en)* | 1987-06-29 | 1989-01-17 | ||
| JPH0180688U (en)* | 1987-11-19 | 1989-05-30 | ||
| EP0523550B1 (en)* | 1991-07-10 | 1997-01-15 | Ebara Corporation | Screw vacuum pump |
| US5314320A (en)* | 1991-07-10 | 1994-05-24 | Ebara Corporation | Screw vacuum pump with a reduced starting load |
| US5374170A (en)* | 1991-07-10 | 1994-12-20 | Ebara Corporation | Screw vacuum pump |
| US5674063A (en)* | 1994-08-19 | 1997-10-07 | Diavac Limited | Screw fluid machine and screw gear used in the same |
| EP0697523A2 (en) | 1994-08-19 | 1996-02-21 | Diavac Limited | Screw fluid machine and screw gear used in the same |
| US5829957A (en)* | 1994-08-19 | 1998-11-03 | Diavac Limited | Screw fluid machine and screw gear used in the same |
| US5836754A (en)* | 1994-08-19 | 1998-11-17 | Diavac Limited | Screw fluid machine and screw gear used in the same |
| US6302641B1 (en) | 2000-01-07 | 2001-10-16 | Kashiyama Kougyou Industry Co., Ltd. | Multiple type vacuum pump |
| US6514035B2 (en) | 2000-01-07 | 2003-02-04 | Kashiyama Kougyou Industry Co., Ltd. | Multiple-type pump |
| JP2012533016A (en)* | 2009-07-10 | 2012-12-20 | ロブスキ・エッセ・ピ・ア | Dry screwdriver |
| US11248606B2 (en) | 2014-04-25 | 2022-02-15 | Kaeser Kompressoren Se | Rotor pair for a compression block of a screw machine |
| EP3597920A3 (en)* | 2014-04-25 | 2021-03-24 | Kaeser Kompressoren Se | Rotor pair for a compressor block of a screw machine |
| US12352266B2 (en) | 2014-04-25 | 2025-07-08 | Kaeser Kompressoren Se | Rotor pair for a compression block of a screw machine |
| US10975867B2 (en) | 2015-10-30 | 2021-04-13 | Gardner Denver, Inc. | Complex screw rotors |
| US11644034B2 (en) | 2015-10-30 | 2023-05-09 | Gardner Denver, Inc. | Complex screw rotors |
| US12110888B2 (en) | 2015-10-30 | 2024-10-08 | Industrial Technologies And Services, Llc | Complex screw rotors having multiple helical profiles joined by a centeral portion with a pocket |
| US10738778B2 (en) | 2018-01-22 | 2020-08-11 | Kabushiki Kaisha Toyota Jidoshokki | Motor-driven roots pump |
| Publication number | Publication date |
|---|---|
| JPH079239B2 (en) | 1995-02-01 |
| Publication | Publication Date | Title |
|---|---|---|
| JPS60216089A (en) | screw vacuum pump | |
| US4714418A (en) | Screw type vacuum pump | |
| US8702407B2 (en) | Multistage roots vacuum pump having different tip radius and meshing clearance from inlet stage to exhaust stage | |
| JP2001207984A (en) | Vacuum exhaust device | |
| JPS62243982A (en) | 2-stage vacuum pump and operating method thereof | |
| JPH066950B2 (en) | Multi-stage roots type vacuum pump | |
| US4934908A (en) | Vacuum pump systems | |
| CN114320917A (en) | A direct discharge type Roots pump | |
| US20030223897A1 (en) | Two-stage rotary screw fluid compressor | |
| US11713761B2 (en) | Screw compressor with a shunt-enhanced decompression and pulsation trap (SEDAPT) | |
| JPS61152990A (en) | Screw vacuum pump | |
| JPS6217389A (en) | Machine pump | |
| JP3661885B2 (en) | Screw vacuum pump and screw gear | |
| US8539936B2 (en) | Supercharger rotor shaft seal pressure equalization | |
| KR100221674B1 (en) | Screw vacuum pump | |
| CN114922818A (en) | Working condition control system applied to double-screw compressor | |
| JP2002174174A (en) | Vacuum exhaust device | |
| US20220074410A1 (en) | Screw compressor with a shunt-enhanced compression and pulsation trap (secapt) | |
| JPH08543Y2 (en) | Oil-cooled screw compressor | |
| JPS63285279A (en) | Vacuum pump shaft sealing device | |
| JP2007263122A (en) | Vacuum exhaust device | |
| JPH048891A (en) | Multistage roots type vacuum pump | |
| JP4294212B2 (en) | High pressure screw compressor | |
| JP2007298043A (en) | Vacuum exhaust device | |
| EP4230870A1 (en) | Screw compressor with a shunt-enhanced compression and pulsation trap (secapt) |