JPH0733823B2 - How to operate an oil-free positive displacement compressor - Google Patents
How to operate an oil-free positive displacement compressorInfo
- Publication number
- JPH0733823B2 JPH0733823B2 JP61304957A JP30495786A JPH0733823B2 JP H0733823 B2 JPH0733823 B2 JP H0733823B2 JP 61304957 A JP61304957 A JP 61304957A JP 30495786 A JP30495786 A JP 30495786A JP H0733823 B2 JPH0733823 B2 JP H0733823B2
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- JP
- Japan
- Prior art keywords
- temperature
- gas
- pressure
- discharge
- air
- 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.)
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- Applications Or Details Of Rotary Compressors (AREA)
- Compressor (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、例えば無給油式スクリュ圧縮機等の無給油式
容積型圧縮機の運転方法に関するものである。TECHNICAL FIELD The present invention relates to a method for operating an oil-free positive displacement compressor such as an oil-free screw compressor.
（従来の技術） 従来、例えば単段無給油式スクリュ圧縮機は圧縮時の温
度上昇のため吐出圧力はせいぜい２〜4kg/cm2G程度であ
ったが、今日ではロータ歯形の改良、加工精度の改善に
よって吐出圧力が7.0kg/cm2G程度のものまで商品化され
ている。そして、吐出圧力を7.0kg/cm2Gにした場合に
は、吐出ガスの温度は330〜340℃まで上昇する。(Prior Art) Conventionally, for example, in a single-stage oil-free screw compressor, the discharge pressure was at most about 2 to 4 kg / cm 2 G due to the temperature rise at the time of compression. Due to the improvement of, the discharge pressure has been commercialized up to about 7.0 kg / cm 2 G. Then, when the discharge pressure is 7.0 kg / cm 2 G, the temperature of the discharge gas rises to 330 to 340 ° C.
ところが、市場では、さらに高い10kg/cm2Gに近い吐出
圧力が要求される傾向にあるが、例えば吐出圧力を8.5
〜8.8kg/cm2Gまで上げるために、内部圧力比だけを大き
くしたのでは吐出ガス温度が380〜400℃まで上昇するこ
とになり、ロータ歯形の改良等だけで熱膨張によるロー
タ接触を防ぐことは非常に難しくなる。However, the market tends to require even higher discharge pressures near 10 kg / cm 2 G.
If only the internal pressure ratio is increased to raise to ~ 8.8 kg / cm 2 G, the discharge gas temperature will rise to 380 to 400 ° C, and rotor contact due to thermal expansion can be prevented only by improving the rotor tooth profile. Things get very difficult.
また、空冷圧縮機では吐出圧力が7kg/cm2Gでも吐出ガス
温度が上昇し過ぎるのが実情である。Moreover, in the air-cooled compressor, the discharge gas temperature rises too much even when the discharge pressure is 7 kg / cm 2 G.
いずれにしても、吐出圧力を上昇させようとすると、吐
出ガス温度の上昇は避けられず、運転時のロータ歯形の
隙間管理が極めて困難になるという問題がある。In any case, when trying to raise the discharge pressure, the rise of the discharge gas temperature is unavoidable, and there is a problem that it becomes extremely difficult to manage the clearance of the rotor tooth profile during operation.
（問題点を解決するための手段） 上記問題点を解決するために、本発明は、圧縮過程中の
空間、あるいは吐出ポート近傍の吐出空間に、 但し、Ta:供給ガスの温度（゜Ｋ） T1:供給前の圧縮ガスの温度（゜Ｋ） κ：ポリトロープ指数 なる関係を満たす温度Taで、上記空間より高い圧力のガ
スを供給するようにした。(Means for Solving Problems) In order to solve the above problems, the present invention provides a space during a compression process or a discharge space near a discharge port, However, Ta: temperature of supply gas (° K) T 1 : temperature of compressed gas before supply (° K) κ: temperature Ta that satisfies the relationship of polytropic index, so that gas with a pressure higher than the above space is supplied. did.
（実施例） 次に、本発明の一実施例を図面にしたがって説明する。(Embodiment) Next, an embodiment of the present invention will be described with reference to the drawings.
第１図は、本発明に係る方法を適用した無給油式スクリ
ュ圧縮機を示し、吸込流路１から圧縮機本体2,吐出流路
３へと続くガス流路を形成するとともに、吐出流路３に
はアフタークーラ４および逆止弁５が設けてある。さら
に、吐出流路３のアフタークーラ４と逆止弁５との中間
部分から圧縮機本体２内の図示しないロータ室の所定位
置に至る戻しガス流路６を設けて、圧縮過程中のロータ
室内の空間にアフタークーラ４で冷却されたガスの一部
を戻すように形成してある。すなわち、上記ロータ室の
所定位置は 但し、Ta:供給ガス、すなわち本実施例では戻しガス流
路６から戻してロータ室内へ供給するガスの温度（゜
Ｋ） T1:供給前の圧縮ガスの温度（゜Ｋ） κ：ポリトロープ指数 なる関係を満たす所に限定され、通常は吸込口近傍にな
ることはなく、図示しない吐出ポート近傍が断熱効率を
高めるうえで好ましい。FIG. 1 shows an oil-free screw compressor to which the method according to the present invention is applied, in which a gas flow passage from the suction flow passage 1 to the compressor body 2 and the discharge flow passage 3 is formed, and the discharge flow passage is formed. 3, an aftercooler 4 and a check valve 5 are provided. Further, a return gas passage 6 is provided from an intermediate portion of the discharge passage 3 between the aftercooler 4 and the check valve 5 to a predetermined position of a rotor chamber (not shown) in the compressor body 2, so that the rotor chamber during the compression process is provided. It is formed so that a part of the gas cooled by the aftercooler 4 is returned to the space. That is, the predetermined position of the rotor chamber is Here, Ta is the supply gas, that is, the temperature (° K) of the gas which is returned from the return gas flow path 6 and is supplied into the rotor chamber in the present embodiment T 1 : The temperature of the compressed gas before the supply (° K) κ: Polytropic index It is limited to a place satisfying the following relationship, and normally it is not near the suction port, and the vicinity of the discharge port (not shown) is preferable in order to improve the adiabatic efficiency.
そして、後述する熱力学式により示すように、吐出ガス
温度の上昇を伴わずに吐出圧力を上昇させるように形成
してある。Then, as indicated by a thermodynamic equation described later, the discharge pressure is increased without increasing the discharge gas temperature.
このように、上記装置の構成から明らかなように、本発
明に係る運転方法の実施例は、無給油式スクリュ圧縮機
に適用して、アフタークーラ４で冷却された吐出ガスの
一部を圧縮過程中のロータ室内の空間に供給するように
し、かつ上記（１）式を満たすようにしたものである。Thus, as is apparent from the configuration of the above apparatus, the embodiment of the operating method according to the present invention is applied to an oil-free screw compressor to compress a part of the discharge gas cooled by the aftercooler 4. It is designed such that it is supplied to the space in the rotor chamber during the process and satisfies the above formula (1).
そこで、この（１）式の導出過程について説明する。Therefore, the process of deriving the equation (1) will be described.
ガス体を断熱圧縮したときの、圧縮ガスの圧力P1と温度
T1との間には 但し、Ts:圧縮前の温度、すなわち本実施例では吸込ガ
ス温度（゜Ｋ） Ps:圧縮前の圧力、すなわち本実施例では吸込ガス圧力 の関係が成り立つ。Pressure P 1 and temperature of compressed gas when a gas body is adiabatically compressed
Between T 1 However, the relationship of Ts: temperature before compression, that is, suction gas temperature (° K) in this embodiment, Ps: pressure before compression, that is, suction gas pressure in this embodiment, holds.
これに対して、一定容積にあるガス体（温度、T1,圧力P
1とする。）に、この圧力に供給できる充分高い圧力の
ガス体（温度Taとする。）を混合させて、しかも混合後
のガス体の容積を上記の一定容積のままとした場合にお
ける混合後のガスの温度度Ｔと圧力Ｐとの間には、 の関係が成り立つ。On the other hand, a gas body (temperature, T 1 , pressure P
Set to 1 . ) Is mixed with a gas body (having a temperature Ta) of a sufficiently high pressure that can be supplied to this pressure, and the volume of the gas body after mixing is kept at the above-mentioned constant volume, Between the temperature degree T and the pressure P, The relationship is established.
したがって、 となり、 は必ず正になるので、（４）式の右辺第１項および第３
項は正となり、T1≧κTaの場合は、（４）式の右辺は≧
０となる。Therefore, Next to Is always positive, so the first term and the third term on the right side of equation (4)
The term is positive, and when T 1 ≧ κTa, the right side of equation (4) is ≧
It becomes 0.
このことは、T1≧κTaの場合はガスの圧力如何に拘わず
T1≧Ｔとなり、供給ガスにより圧力は上昇しても温度が
上昇することはないことを意味している。This means that when T 1 ≧ κTa, it is irrespective of the gas pressure.
T 1 ≧ T, which means that the temperature does not rise even if the pressure rises due to the supply gas.
次に、ガスが空気（κ＝1.4）である場合の具体例とし
て、T1＝κTaで、かつTaが吸込ガスの温度に等しい、す
なわちTa＝Tsのときを考えると、（２）式が、 となり、κ＝1.4であるから、P1/Ps＝3.25となる。Next, as a specific example in the case where the gas is air (κ = 1.4), consider the case where T 1 = κTa and Ta is equal to the temperature of the suction gas, that is, Ta = Ts. , And κ = 1.4, so P 1 / Ps = 3.25.
したがって、第２図（横軸：圧力比P/Ps,縦軸：温度比T
/Ts）に示すように、吸込ガスのみ断熱圧縮した場合の
圧力と温度は（２）式と同じ関係にあり、曲線Ｉのよう
に変化するのに対して、この曲線Ｉの途中の状態の空気
に、その状態での圧力で、温度Ta、ここでは温度Tsの空
気を混合させたときの混合後の空気の状態は破線で示す
曲線群IIで示される。ここで、曲線群IIの曲線Ｉ上の始
点における温度Ｔ、圧力Ｐが、（３）式における温度
T1,圧力P1に相当し、混合させる空気が多くなるにした
がって、混合後の状態は第２図中破線で示す曲線上のよ
り右方の点で定まる状態となる。すなわち、上記スクリ
ュ圧縮機において、供給空気により圧力上昇が起るこ
と、および圧力比P1/Ps＝3.25となるロータ室内の圧縮
空間の部分を境として、これより高圧側すなわち吐出口
に近づく程、供給ガスによる冷却効果は大きく、逆に低
圧側すなわち吸込口に近づく程、供給ガスによる温度上
昇が著しくなることが示されている。Therefore, Fig. 2 (horizontal axis: pressure ratio P / Ps, vertical axis: temperature ratio T
/ Ts), the pressure and temperature when only the suction gas is adiabatically compressed have the same relationship as in equation (2) and change as shown by curve I. The state of the air after mixing when the air at the temperature Ta, here the temperature Ts, is mixed with the air at the pressure in that state is shown by a curve group II indicated by a broken line. Here, the temperature T and the pressure P at the starting point on the curve I of the curve group II are the temperatures in the equation (3).
Corresponding to T 1 and pressure P 1 , as the amount of air to be mixed increases, the state after mixing becomes a state determined at the point on the right side of the curve indicated by the broken line in FIG. That is, in the above-mentioned screw compressor, the pressure rises due to the supply air, and the compression space portion in the rotor chamber where the pressure ratio P 1 /Ps=3.25 becomes the boundary, the closer to the high pressure side, that is, the discharge port. It has been shown that the cooling effect by the supply gas is large, and conversely, the temperature rise due to the supply gas becomes more remarkable as the pressure becomes closer to the low pressure side, that is, the suction port.
以上、空気の例で示したようにT1≧κTaなる条件は、供
給空気の温度Taを例えばTa＝Tsのように限定した場合に
は、圧力条件によって表現することができ、上記の例で
は圧力比P1/Ps≧3.25を満たす位置ということになる
が、これを決める基本はあくまでT1≧κTaなる条件であ
る。As described above, the condition of T 1 ≧ κTa as shown in the example of air can be expressed by the pressure condition when the temperature Ta of the supply air is limited to Ta = Ts. In the above example, It is a position that satisfies the pressure ratio P 1 / Ps ≧ 3.25, but the basis for determining this is the condition that T 1 ≧ κTa.
現実には、消費動力の増加が大きくなってもより高圧の
ガスを得たいという要求が多いこと、ならびに消費動力
とガス圧力とは異質のものであることから、両者の数値
を単純に比較して圧縮機の良否を判断することはできな
いが、本発明に係る運転方法による場合、上記の空気を
用いた例では、本発明を採用しない場合に対する吐出空
気温度と消費動力の変化の計算結果は以下の通りにな
る。In reality, there are many demands for obtaining higher pressure gas even if the consumption power increases greatly, and since the consumption power and gas pressure are different, a simple comparison is made between the two values. Although it is not possible to judge the quality of the compressor by means of the operating method according to the present invention, in the example using the above air, the calculation results of the change in the discharge air temperature and the power consumption with respect to the case without the present invention It becomes as follows.
なお、この計算は上記空気の場合の条件を採用した他、
空気の供給位置を、供給後ロータによる圧縮がない吐出
直前のロータ室部分として行なったものである。また、
上記の表の吐出ガス温度比、消費動力比は、空気を供給
しない場合に対する空気を供給した場合の吐出ガス温
度、消費動力の各々の比を表わしている。 This calculation uses the conditions for the above air,
The position where the air is supplied is set as the rotor chamber portion immediately before the discharge after the supply without the compression by the rotor. Also,
The discharge gas temperature ratio and the consumption power ratio in the above table represent the ratios of the discharge gas temperature and the consumption power when air is supplied as compared to when air is not supplied.
この計算結果から、高圧低温空気を循環使用することに
より、温度上昇を大幅に制限し、かつ動力増加も小さい
ことが明らかになっている。From this calculation result, it is clarified that the temperature increase is significantly limited and the power increase is small by circulating the high pressure low temperature air.
このように、空気の供給位置はできる限り吐出口側、す
なわち吐出ポート近傍が望ましいが、圧縮機の構造によ
り若干の消費動力の増加を許容する場合には、Ta≦T1/
κなる条件を満たす限りにおいて適宜吸込口側に移動さ
せることもできる。As described above, it is desirable that the air supply position is on the discharge port side, that is, near the discharge port as much as possible, but if the structure of the compressor allows a slight increase in power consumption, Ta ≦ T 1 /
It can also be appropriately moved to the suction port side as long as the condition of κ is satisfied.
また、理論上温度Taはいくらでも低い温度にすることが
考えられるが、一般的には供給する空気としてアフター
クーラ後の自前の空気を使うことが考えられるので、温
度Taは吸込空気の温度Tsに略等しくなり、第２図の供給
圧力が3.25より上方が現実的な部分といえる。In theory, it is possible to set the temperature Ta as low as possible, but in general, it is possible to use the own air after the after-cooler as the air to be supplied, so the temperature Ta is set to the temperature Ts of the suction air. It becomes almost equal, and it can be said that the realistic part is when the supply pressure in Fig. 2 is above 3.25.
なお、上記実施例では無給油式スクリュ圧縮機について
説明したが、本発明はこれに限るものでなく、無給油式
容積型圧縮機全般への適用を含めたものである。Although the oilless screw compressor has been described in the above embodiment, the present invention is not limited to this, and includes application to all oilless positive displacement compressors.
また、供給ガスは空気に限らず、供給方法も吐出ガスの
一部を分岐させる外、他に高圧ガス源がある場合にはそ
れを使用してもよく、上記実施例には限定されるもので
はない。Further, the supply gas is not limited to air, and the supply method is not limited to the above-mentioned embodiment, in addition to branching a part of the discharge gas, if there is another high-pressure gas source, it may be used. is not.
さらに、供給位置も、ロータ室内の圧縮過程中の空間に
限らず、吐出ポート近傍の吐出空間においても上述した
ガスの状態変化の関係は成立し、本発明はこの部分をも
含むものである。Further, the supply position is not limited to the space during the compression process in the rotor chamber, and the relationship of the gas state change described above is established not only in the discharge space near the discharge port, but the present invention also includes this portion.
（発明の効果） 以上の説明より明らかなように、本発明によれば、圧縮
過程中の空間、あるいは吐出ポート近傍の吐出空間に、 但し、Ta:供給ガスの温度（゜Ｋ） T1:供給前の圧縮ガスの温度（゜Ｋ） κ：ポリトロープ指数 なる関係を満たす温度Taで、上記空間より高い圧力のガ
スを供給するようにしてある。(Effects of the Invention) As is apparent from the above description, according to the present invention, in the space during the compression process, or in the discharge space near the discharge port, However, Ta: temperature of supply gas (° K) T 1 : temperature of compressed gas before supply (° K) κ: temperature at which Ta satisfies the relationship of polytropic index, and gas with a pressure higher than the above space is supplied. There is.
このため、温度上昇を伴うことなく、かつ消費動力の僅
かな増大のみで、吐出ガスの圧力を上昇させることが可
能となり、熱膨張による制限を緩和して、より高圧の吐
出ガスを得ることができるという効果を奏する。Therefore, it is possible to increase the pressure of the discharge gas without increasing the temperature and only by slightly increasing the power consumption, and the restriction due to thermal expansion can be relaxed to obtain a higher pressure discharge gas. It has the effect of being able to.
第１図は本発明に係る運転方法を適用した無給油式スク
リュ圧縮機のブロック図、第２図は圧縮過程部分への空
気の供給前後の状態を示す図である。FIG. 1 is a block diagram of an oil-free screw compressor to which an operating method according to the present invention is applied, and FIG. 2 is a diagram showing states before and after supplying air to a compression process portion.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 実開 昭52−60909（ＪＰ，Ｕ) ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Bibliographic references Sho 52-60909 (JP, U)
Claims (1)
傍の吐出空間に、 但し、Ta:供給ガスの温度（゜Ｋ） T1:供給前の圧縮ガスの温度（゜Ｋ） κ：ポリトロープ指数 なる関係を満たす温度Taで、上記空間より高い圧力のガ
スを供給することを特徴とする無給油式容積型圧縮機の
運転方法。1. A space during a compression process or a discharge space near a discharge port, However, Ta: temperature of supply gas (° K) T 1 : temperature of compressed gas before supply (° K) κ: temperature Ta satisfying the relationship of polytropic index, and gas of higher pressure than the above space must be supplied. A method of operating a characteristic oilless positive displacement compressor.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61304957A JPH0733823B2 (en) | 1986-12-19 | 1986-12-19 | How to operate an oil-free positive displacement compressor |
| US07/079,397 US4812110A (en) | 1986-08-11 | 1987-07-30 | Oil-free screw compressor with bypass of cooled discharged gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61304957A JPH0733823B2 (en) | 1986-12-19 | 1986-12-19 | How to operate an oil-free positive displacement compressor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63159683A JPS63159683A (en) | 1988-07-02 |
| JPH0733823B2 true JPH0733823B2 (en) | 1995-04-12 |
Family
ID=17939349
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61304957A Expired - Fee Related JPH0733823B2 (en) | 1986-08-11 | 1986-12-19 | How to operate an oil-free positive displacement compressor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0733823B2 (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5436324Y2 (en) * | 1975-10-30 | 1979-11-02 |
-
1986
- 1986-12-19 JP JP61304957A patent/JPH0733823B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63159683A (en) | 1988-07-02 |
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|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |