JP3438356B2 - Multi-stage centrifugal compressor - Google Patents
Multi-stage centrifugal compressorInfo
- Publication number
- JP3438356B2 JP3438356B2 JP30109994A JP30109994A JP3438356B2 JP 3438356 B2 JP3438356 B2 JP 3438356B2 JP 30109994 A JP30109994 A JP 30109994A JP 30109994 A JP30109994 A JP 30109994A JP 3438356 B2 JP3438356 B2 JP 3438356B2
- Authority
- JP
- Japan
- Prior art keywords
- centrifugal compressor
- stage
- diffuser
- stage centrifugal
- vanes
- 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
- 238000011144 upstream manufacturing Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
Landscapes
- Structures Of Non-Positive Displacement Pumps (AREA)
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、多段式遠心圧縮機に関
する。
【０００２】
【従来の技術】図１に、第１段遠心圧縮機１と第２段遠
心圧縮機２とを直列に接続した二段式遠心圧縮機３の概
要を示す。図示するように、第１段遠心圧縮機１のイン
ペラ４と第２段遠心圧縮機２のインペラ５とが、回転軸
６を介して背中合わせに接続されている。回転軸６には
小径歯車７が設けられている。小径歯車７はアイドル歯
車８に噛合されている。アイドル歯車８はモータ９の駆
動軸１０に設けられた大径歯車１１に噛合されている。
この構成によれば、モータ９が駆動すると、各インペラ
４，５が同期して高速回転することになる。
【０００３】各インペラ４，５は、それぞれハウジング
１２ａ，１２ｂ内に収容されている。ハウジング１２
は、吸気管１３とインペラケース１４とディフューザ１
５と渦巻室１６とから構成されている。第１段遠心圧縮
機１の渦巻室１６ａは、連絡管１７を介して第２段遠心
圧縮機２の吸気管１３ｂに接続されている。連絡管１７
には、インタークーラ１８が介設されている。第２段遠
心圧縮機２の渦巻室１６ｂには、吐出管１９が接続され
ている。吐出管１９には、アフタークーラ２０が介設さ
れている。この構成によれば、空気は、第１段遠心圧縮
機１の吸気管１３ａに吸い込まれ、インペラ４により径
方向外方に加速され、ディフューザ１５ａにより減速さ
れ速度が圧力に変換されて渦巻室１６ａに導かれる。渦
巻室１６ａ内の空気は、インタークーラ１８により冷却
された後、第２段遠心圧縮機２の吸気管１３ｂに吸い込
まれ、同様にインペラ５→ディフューザ１５ｂ→渦巻室
１６ｂ→アフタークーラ２０へと流れ、吐出管１９から
吐出される。
【０００４】上記ディフューザ１５ａ，１５ｂは、図３
に示すように、インペラ４，５の回転方向に沿って斜め
に放射状に配置された複数のベーン２１を備えている。
ベーン２１は、ある設計点回りの流量に合わせて、その
枚数や取付角度等が設定されている。ベーン２１の数を
増やすと、設計点回りの流量での効率が高くなるもの
の、設計点を外れた流量では著しく効率が低くなり、使
用可能な流量範囲が狭くなってしまう。かかるディフュ
ーザ１５のベーン２１は、従来、第１段遠心圧縮機１と
第２段遠心圧縮機２とで同じソリディティのものが用い
られていた。なお、ソリディティとは、図４に示すよう
に、ベーンのコードをベーンのピッチで割った値をい
う。
【０００５】
【発明が解決しようとする課題】ところで、上述の如き
二段式遠心圧縮機３においては、吸気管１３ａから吸い
込まれた空気は、第１段遠心圧縮機１によって圧縮され
その容積が小さくなった後、第２段遠心圧縮機２に吸い
込まれる。従って、ディフューザ１５のベーン２１を第
１段遠心圧縮機１と第２段遠心圧縮機２とで相似のもの
（同じソリディティのもの）を用いると、図３に示すよ
うに、第２段遠心圧縮機２の使用可能な流量範囲が狭く
なってしまうという問題が生じる。
【０００６】例えば、第１段遠心圧縮機１のチョーク点
２２は、第２段遠心圧縮機２のチョーク点２３に符合
し、第１段遠心圧縮機１のストール点２４は、第２段遠
心圧縮機２のストール点２５に符合する。このため、第
２段遠心圧縮機２の使用可能な流量範囲が狭くなり、二
段式遠心圧縮機３全体としての使用可能な流量範囲（こ
の範囲は専ら第２段遠心圧縮機２に依存する）が狭くな
っていた。
【０００７】また、ディフューザ１５のベーン２１を第
１段側と第２段側とで相似のものを用いると、全体とし
てそこそこの性能（効率および使用範囲）が得られるよ
うにベーン２１のソリディティの設計がなされるため、
第１段側のディフューザ１５ａの効率が不十分で、第２
段側のディフューザ１５ｂの使用範囲が狭くなってい
た。
【０００８】以上の事情を考慮して創案された本発明の
目的は、全体としての効率を向上させ、且つ広い使用範
囲を得ることができる多段式遠心圧縮機を提供すること
にある。
【０００９】
【課題を解決するための手段】上記目的を達成すべく本
発明は、遠心圧縮機を複数直列に接続し、隣接する前後
段の遠心圧縮機のうち、後段側の遠心圧縮機のディフュ
ーザのベーンのソリディティを、前段側の遠心圧縮機の
ディフューザのベーンのソリディティより小さくし、各
段のソリディティを前段側から後段側にかけて徐々に小
さくしたものである。
【００１０】
【作用】上記構成によれば、前段側の遠心圧縮機のディ
フューザのベーンのソリディティが大きいので所定の設
計点回りで高効率を得、後段側の遠心圧縮機のディフュ
ーザのベーンのソリディティが小さいので広い使用範囲
を得る。すなわち、効率の向上は前段側のディフューザ
により達成され、その結果ピークが高まり使用範囲が狭
まってもそれは後段側のディフューザにより解消され
る。よって、全体として効率が向上すると共に使用範囲
が広くなる。
【００１１】
【実施例】本発明の一実施例を添付図面に基づいて説明
する。
【００１２】図２は、前述した図１に示す二段式遠心圧
縮機３の各段のディフューザ１５ａ，１５ｂを示す図で
ある。図示するように、第１段遠心圧縮機１のディフュ
ーザ１５ａのベーン２１のソリディティが、第２段遠心
圧縮機２のディフューザ１５ｂのベーン２１のソリディ
ティより大きくなっている。具体的には、第１段側のデ
ィフューザ１５ａのベーン２１の数は１３枚であり、第
２段側のディフューザ１５ｂのベーン２１の数は８枚で
ある。第１段側のディフューザ１５ａのベーン２１の数
（１３枚）は図３に示す従来のもの（１０枚）より多
く、第２段側のディフューザ１５ｂのベーン２１の数
（８枚）は図３に示す従来のもの（１０枚）より少な
い。
【００１３】このため、第１段側のディフューザ１５ａ
の効率はピークが高く使用範囲が狭くなり、第２段側の
ディフューザ１５ｂの効率はピークが低く使用範囲が広
くなる。詳しくは、図２に示すように第１段側のチョー
ク点２６が第２段側のチョーク点２７に符合し、第１段
側のストール点２８が第２段側のストール点２９に符合
するように、各段のディフューザ１５ａ，１５ｂのソリ
ディティ（ベーン２１のピッチおよびコード即ち枚数お
よび翼弦長）が設定される。よって、空気が第１段遠心
圧縮機１により圧縮されて第２段遠心圧縮機２に導入さ
れても、図中破線で示す従来のものように第２段側の使
用範囲が狭まることはない。すなわち、効率の向上は専
ら前段側のディフューザ１５ａにより達成され、その結
果ピークが高まり使用範囲が狭まってもそれは後段側の
ディフューザ１５ｂにより解消される。よって、全体と
して効率が向上すると共に使用範囲が広くなる。
【００１４】第１段側のディフューザ１５ａのベーン２
１のソリディティをどの程度増やし、第２段側のディフ
ューザ１５ｂのベーン２１のソリディティをどの程度減
すかについては、個々の機械によってまた効率を優先す
るか使用範囲を優先するかによって異なる。
【００１５】なお、本実施例のように二段式遠心圧縮機
のみならず、三段式四段式の遠心圧縮機に本発明を適用
してもよいことは勿論である。この場合、第１段側から
第２段側第３段側へ向けてディフューザのベーンの枚数
が徐々に少なくなっていく。また、ベーン２１の数を変
更するのではなく、ベーン２１のコードを変更してソリ
ディティを変えてもよい。この場合、前段側ディフュー
ザ１５ａのベーン２１のコードを、後段側ディフューザ
１５ｂのベーン２１のコードより長くする。また、ピッ
チとコードの双方を変更してもよい。
【００１６】
【発明の効果】以上説明したように本発明に係る多段式
遠心圧縮機によれば、全体としての効率を向上させ、且
つ広い使用範囲を得ることができる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multistage centrifugal compressor. FIG. 1 shows an outline of a two-stage centrifugal compressor 3 in which a first-stage centrifugal compressor 1 and a second-stage centrifugal compressor 2 are connected in series. As shown, the impeller 4 of the first-stage centrifugal compressor 1 and the impeller 5 of the second-stage centrifugal compressor 2 are connected back to back via a rotating shaft 6. The rotary shaft 6 is provided with a small-diameter gear 7. The small diameter gear 7 is meshed with the idle gear 8. The idle gear 8 is meshed with a large-diameter gear 11 provided on a drive shaft 10 of a motor 9.
According to this configuration, when the motor 9 is driven, the impellers 4 and 5 rotate at high speed in synchronization. The impellers 4 and 5 are housed in housings 12a and 12b, respectively. Housing 12
Are the intake pipe 13, impeller case 14 and diffuser 1
5 and a spiral chamber 16. The spiral chamber 16a of the first-stage centrifugal compressor 1 is connected to an intake pipe 13b of the second-stage centrifugal compressor 2 via a communication pipe 17. Connecting pipe 17
, An intercooler 18 is interposed. A discharge pipe 19 is connected to the spiral chamber 16 b of the second-stage centrifugal compressor 2. The discharge pipe 19 is provided with an aftercooler 20. According to this configuration, air is sucked into the intake pipe 13a of the first-stage centrifugal compressor 1, is accelerated radially outward by the impeller 4, is decelerated by the diffuser 15a, is converted into speed, and is converted into pressure. It is led to. The air in the spiral chamber 16a is cooled by the intercooler 18 and then sucked into the intake pipe 13b of the second-stage centrifugal compressor 2, and similarly flows to the impeller 5 → the diffuser 15b → the spiral chamber 16b → the aftercooler 20. Are discharged from the discharge pipe 19. [0004] The diffusers 15a and 15b are shown in FIG.
As shown in FIG. 2, the air conditioner includes a plurality of vanes 21 arranged obliquely radially along the rotation direction of the impellers 4 and 5.
The number of vanes 21 and the mounting angle are set in accordance with the flow rate around a certain design point. Increasing the number of vanes 21 increases the efficiency at a flow rate around the design point, but significantly reduces the efficiency at a flow rate outside the design point, narrowing the usable flow rate range. Conventionally, the vanes 21 of the diffuser 15 have the same solidity for the first stage centrifugal compressor 1 and the second stage centrifugal compressor 2. The solidity refers to a value obtained by dividing a vane code by a vane pitch, as shown in FIG. In the two-stage centrifugal compressor 3 as described above, the air sucked from the intake pipe 13a is compressed by the first-stage centrifugal compressor 1 and its volume is reduced. After being reduced, it is sucked into the second stage centrifugal compressor 2. Therefore, when the vanes 21 of the diffuser 15 are similar (the same solidity) between the first-stage centrifugal compressor 1 and the second-stage centrifugal compressor 2, as shown in FIG. There is a problem that the usable flow rate range of the machine 2 becomes narrow. For example, the choke point 22 of the first-stage centrifugal compressor 1 corresponds to the choke point 23 of the second-stage centrifugal compressor 2, and the stall point 24 of the first-stage centrifugal compressor 1 corresponds to the second-stage centrifugal compressor. It corresponds to the stall point 25 of the compressor 2. For this reason, the usable flow rate range of the second-stage centrifugal compressor 2 is narrowed, and the usable flow rate range of the two-stage centrifugal compressor 3 as a whole (this range exclusively depends on the second-stage centrifugal compressor 2) ) Was narrowing. [0007] When the vanes 21 of the diffuser 15 are similar in the first stage and the second stage, the solidity of the vanes 21 is adjusted so that a reasonable performance (efficiency and range of use) can be obtained as a whole. Because the design is made,
The efficiency of the first stage diffuser 15a is insufficient,
The use range of the step-side diffuser 15b was narrow. An object of the present invention, which has been made in view of the above circumstances, is to provide a multi-stage centrifugal compressor capable of improving overall efficiency and obtaining a wide range of use. [0009] To achieve the above object, according to the present invention, there is provided a centrifugal compressor connected to a plurality series, adjacent longitudinal
Among the centrifugal compressors of the stages, the solidity of the vanes of the diffuser of the downstream centrifugal compressor is smaller than the solidity of the vanes of the diffuser of the upstream centrifugal compressor , and
Gradually lower the solidity from the front to the rear.
It is a crunch . According to the above construction, the solidity of the vanes of the diffuser of the front-stage centrifugal compressor is large, so that high efficiency is obtained around a predetermined design point, and the solidity of the vanes of the diffuser of the rear-stage centrifugal compressor is increased. Is small, so a wide range of use is obtained. That is, the efficiency improvement is achieved by the front diffuser, and as a result, even if the peak is increased and the use range is narrowed, it is eliminated by the rear diffuser. Therefore, the efficiency is improved as a whole and the use range is widened. An embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 2 is a view showing the diffusers 15a and 15b at each stage of the two-stage centrifugal compressor 3 shown in FIG. As shown in the drawing, the solidity of the vanes 21 of the diffuser 15a of the first-stage centrifugal compressor 1 is larger than the solidity of the vanes 21 of the diffuser 15b of the second-stage centrifugal compressor 2. Specifically, the number of the vanes 21 of the first stage diffuser 15a is thirteen, and the number of the vanes 21 of the second stage diffuser 15b is eight. The number (13) of vanes 21 of the first-stage diffuser 15a is larger than that of the conventional one (10) shown in FIG. 3, and the number (8) of vanes 21 of the second-stage diffuser 15b is FIG. (10 sheets). For this reason, the first stage diffuser 15a
The efficiency of the diffuser 15b on the second stage side has a low peak and a wide use range, while the peak efficiency is high and the use range is narrow. Specifically, as shown in FIG. 2, the choke point 26 on the first stage matches the choke point 27 on the second stage, and the stall point 28 on the first stage matches the stall point 29 on the second stage. In this manner, the solidity (the pitch and the code of the vanes 21, that is, the number and the chord length) of the diffusers 15 a and 15 b in each stage is set. Therefore, even if the air is compressed by the first-stage centrifugal compressor 1 and introduced into the second-stage centrifugal compressor 2, the use range of the second stage is not narrowed unlike the conventional one shown by the broken line in the figure. . That is, the improvement of the efficiency is mainly achieved by the front diffuser 15a. As a result, even if the peak is increased and the use range is narrowed, it is eliminated by the rear diffuser 15b. Therefore, the efficiency is improved as a whole and the use range is widened. Vane 2 of first stage diffuser 15a
The extent to which the solidity of the first stage is increased and the extent to which the vane 21 of the diffuser 15b on the second stage side is decreased depends on the individual machine and whether the priority is given to the efficiency or the use range. It is needless to say that the present invention may be applied not only to a two-stage centrifugal compressor as in this embodiment but also to a three-stage four-stage centrifugal compressor. In this case, the number of vanes of the diffuser gradually decreases from the first stage to the second stage and the third stage. Instead of changing the number of vanes 21, the code of the vanes 21 may be changed to change the solidity. In this case, the code of the vane 21 of the front diffuser 15a is made longer than the code of the vane 21 of the rear diffuser 15b. Further, both the pitch and the chord may be changed. As described above, according to the multistage centrifugal compressor according to the present invention, overall efficiency can be improved and a wide range of use can be obtained.
【図面の簡単な説明】
【図１】二段式遠心圧縮機の説明図である。
【図２】本発明の一実施例を示すディフューザの説明図
である。
【図３】従来例を示すディフューザの説明図である。
【図４】ソリディティを説明するためのディフューザの
概略図である。
【符号の説明】
１ 第１段遠心圧縮機
２ 第２段遠心圧縮機
３ 二段式遠心圧縮機
１５ａ 第１段側ディフューザ
１５ｂ 第２段側ディフューザ
２１ ベーンBRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of a two-stage centrifugal compressor. FIG. 2 is an explanatory view of a diffuser showing one embodiment of the present invention. FIG. 3 is an explanatory diagram of a diffuser showing a conventional example. FIG. 4 is a schematic view of a diffuser for explaining solidity. [Description of Signs] 1 First-stage centrifugal compressor 2 Second-stage centrifugal compressor 3 Two-stage centrifugal compressor 15a First-stage diffuser 15b Second-stage diffuser 21 Vane
Claims (1)
る前後段の遠心圧縮機のうち、後段側の遠心圧縮機のデ
ィフューザのベーンのソリディティを、前段側の遠心圧
縮機のディフューザのベーンのソリディティより小さく
し、各段のソリディティを前段側から後段側にかけて徐
々に小さくしたことを特徴とする多段式遠心圧縮機。(57) Connect the Patent Claims 1. A centrifugal compressor multiple series, adjacent to
Among the centrifugal compressors in the front and rear stages, the solidity of the diffuser vane of the downstream centrifugal compressor is smaller than the solidity of the diffuser vane of the upstream centrifugal compressor , and the solidity of each stage is changed from the front side to the rear side. To Xu
A multi-stage centrifugal compressor characterized by its small size .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30109994A JP3438356B2 (en) | 1994-12-05 | 1994-12-05 | Multi-stage centrifugal compressor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30109994A JP3438356B2 (en) | 1994-12-05 | 1994-12-05 | Multi-stage centrifugal compressor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08159094A JPH08159094A (en) | 1996-06-18 |
| JP3438356B2 true JP3438356B2 (en) | 2003-08-18 |
Family
ID=17892847
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30109994A Expired - Fee Related JP3438356B2 (en) | 1994-12-05 | 1994-12-05 | Multi-stage centrifugal compressor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3438356B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8348593B2 (en) | 2008-09-02 | 2013-01-08 | Nidec Corporation | Serial axial fan |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ITMI20012169A1 (en) * | 2001-10-18 | 2003-04-18 | Nuovo Pignone Spa | STATIC RETURN CHANNEL PALETTING FOR TWO-DIMENSIONAL CENTRIFUGAL STAGES OF A MULTI-STAGE CENTRIFUGAL COMPRESSOR WITH BEST EFFICIENCY |
| GB2467968B (en) * | 2009-02-24 | 2015-04-22 | Dyson Technology Ltd | Centrifugal compressor with a diffuser |
| JP5863320B2 (en) | 2011-08-05 | 2016-02-16 | 三菱重工コンプレッサ株式会社 | Centrifugal compressor |
-
1994
- 1994-12-05 JP JP30109994A patent/JP3438356B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8348593B2 (en) | 2008-09-02 | 2013-01-08 | Nidec Corporation | Serial axial fan |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08159094A (en) | 1996-06-18 |
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