JPH05322334A - Multi-stage compression freezing cycle and its actuating method - Google Patents
Multi-stage compression freezing cycle and its actuating methodInfo
- Publication number
- JPH05322334A JPH05322334A JP12710292A JP12710292A JPH05322334A JP H05322334 A JPH05322334 A JP H05322334A JP 12710292 A JP12710292 A JP 12710292A JP 12710292 A JP12710292 A JP 12710292A JP H05322334 A JPH05322334 A JP H05322334A
- Authority
- JP
- Japan
- Prior art keywords
- compressor
- stage
- semi
- hermetic
- stage compression
- 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.)
- Pending
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/13—Economisers
Landscapes
- Applications Or Details Of Rotary Compressors (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、冷凍機，空調機の多段
圧縮冷凍サイクルと、これの圧縮機の起動方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multistage compression refrigeration cycle for refrigerators and air conditioners, and a method for starting the compressor of the same.
【０００２】[0002]
【従来の技術】図３はこの種冷凍サイクルの従来技術を
示す系統図である。2. Description of the Related Art FIG. 3 is a system diagram showing a prior art of this type of refrigeration cycle.
【０００３】この図３に示す従来技術では、圧縮機２１
と、油分離器２２と、凝縮器２６と、過冷却器２７と、
過冷却器用膨張弁２８と、主膨張弁２９と、蒸発器３０
と、前記油分離器２２に接続された油タンク２３と、油
冷却器２４と、油濾過器２５とを備えている。そして、
前記圧縮機２１には二段圧縮機が使用されている。In the prior art shown in FIG. 3, the compressor 21
An oil separator 22, a condenser 26, a subcooler 27,
Subcooler expansion valve 28, main expansion valve 29, evaporator 30
And an oil tank 23 connected to the oil separator 22, an oil cooler 24, and an oil filter 25. And
A two-stage compressor is used as the compressor 21.
【０００４】また、二段圧縮冷凍機の従来技術として、
文献「冷凍」１９８８年 ＶＯＬ.６３．Ｎo.７３１の
ｐ．５０の図１０に示す冷凍装置がある。この文献に記
載の技術では、圧縮機の軸受への給油は吐出圧力と中間
圧力との差圧により行う差圧給油方式である。Further, as the prior art of the two-stage compression refrigerator,
Reference “Frozen” 1988 VOL.63. No. 731, p. There are 50 refrigeration systems shown in FIG. In the technique described in this document, oil is supplied to the bearings of the compressor by a differential pressure oil supply method in which the pressure difference between the discharge pressure and the intermediate pressure is used.
【０００５】[0005]
【発明が解決しようとする課題】ところで、図３に示す
従来技術では圧縮機２１に二段圧縮機を使用している。
この二段圧縮機を使用した場合の冷媒の蒸発温度は、約
−６５℃が限度であり、この温度以下に温度を下げるこ
とは冷凍機としての効率（消費電力当たりの冷却能力）
が著しく低下し、ランニングコストの観点からは窒素ガ
ス冷却等の他の方式による冷却の方が優位である。な
お、冷凍装置としては三段圧縮方式を用いることによ
り、蒸発温度が−８０〜−６５℃の超低温領域において
使用することが可能であるが、従来技術は単段圧縮機を
３台組み合わせる方式、またはブースタ側に開放型圧縮
機を使用する方式であり、装置全体が大型化する問題が
あり、メンテナンス作業が容易でないという問題があ
る。By the way, in the prior art shown in FIG. 3, a two-stage compressor is used as the compressor 21.
The evaporation temperature of the refrigerant when this two-stage compressor is used is limited to about -65 ° C, and lowering the temperature below this temperature is the efficiency of the refrigerator (cooling capacity per power consumption).
Is significantly reduced, and from the viewpoint of running cost, cooling by another method such as nitrogen gas cooling is more advantageous. By using a three-stage compression system as a refrigerating device, it is possible to use it in an ultra-low temperature region where the evaporation temperature is −80 to −65 ° C. However, the conventional technique is a system in which three single-stage compressors are combined, Alternatively, an open-type compressor is used on the booster side, which causes a problem that the entire device becomes large and maintenance work is not easy.
【０００６】一方、前掲「冷凍」に記載の従来技術で
は、圧縮機を起動する際に、高段側圧縮機構と低段側圧
縮機構とを同時に起動するようにしている。このため、
起動直後より安定運転に至るまでの過渡状態において一
時的に中間圧力が上昇する。これにより、吐出圧力と中
間圧力との圧力差が低下し、圧縮機の軸受への給油量不
足が生じ、潤滑性能の低下および軸受寿命の低下をもた
らすという問題がある。On the other hand, in the prior art described in "Refrigeration", the high-stage compression mechanism and the low-stage compression mechanism are simultaneously activated when the compressor is activated. For this reason,
The intermediate pressure temporarily rises in the transitional state from immediately after startup until stable operation. As a result, there is a problem in that the pressure difference between the discharge pressure and the intermediate pressure is reduced, the amount of oil supplied to the bearing of the compressor is insufficient, and the lubrication performance and bearing life are reduced.
【０００７】本発明の目的は、装置全体を小型化でき、
かつメンテナンス作業の簡素化を図り得る多段圧縮冷凍
サイクルを提供することにある。The object of the present invention is to reduce the size of the entire apparatus,
Another object of the present invention is to provide a multistage compression refrigeration cycle capable of simplifying maintenance work.
【０００８】本発明の他の目的は、前記多段圧縮冷凍サ
イクルの圧縮機の起動直後より安定運転に至るまでの過
渡状態における中間圧力の上昇を抑制し、給油性能の低
下および圧縮機の軸受の寿命の低下を防止し得る起動方
法を提供することにある。Another object of the present invention is to suppress an increase in intermediate pressure in a transient state from immediately after starting the compressor of the multi-stage compression refrigeration cycle to a stable operation, thereby lowering refueling performance and reducing a bearing of the compressor. An object of the present invention is to provide a starting method capable of preventing a decrease in life.
【０００９】[0009]
【課題を解決するための手段】前記目的は、圧縮機とし
て、第一段の圧縮機構と第二段の圧縮機構とを一体化し
たコンパウンド型の半密閉二段圧縮機と、第三段目の圧
縮機構を有する半密閉単段圧縮機とを組み合わせた三段
圧縮方式を採り入れ、各々の圧縮機に電動機を内蔵する
とともに、各電動機の冷却に冷媒冷却方式を採り入れ、
各圧縮機の軸受への給油に、圧縮機の吐出圧力と中間圧
力との差圧を利用して冷凍機油を供給する差圧供給方式
を採り入れたことにより、達成される。Means for Solving the Problems The above-mentioned object is, as a compressor, a compound type semi-hermetic two-stage compressor in which a first stage compression mechanism and a second stage compression mechanism are integrated, and a third stage Adopting a three-stage compression method that combines with a semi-hermetic single-stage compressor having a compression mechanism of, each compressor has a built-in electric motor, and adopts a refrigerant cooling method to cool each electric motor,
This is achieved by adopting a differential pressure supply system for supplying refrigerating machine oil by utilizing the differential pressure between the discharge pressure of the compressor and the intermediate pressure for oil supply to the bearing of each compressor.
【００１０】また、前記目的はブースタ側に前記半密閉
二段圧縮機を複数台設置し、高段側に前記半密閉単段圧
縮機を１台設置したことにより、さらにブースタ側に前
記半密閉二段圧縮機を１台設置し、高段側に前記半密閉
単段圧縮機を複数台設置したことにより、達成される。Further, the purpose is to install a plurality of the semi-hermetic two-stage compressors on the booster side and one semi-hermetic single-stage compressor on the high stage side, so that the semi-hermetically-sealed ones are further provided on the booster side. This is achieved by installing one two-stage compressor and installing a plurality of the semi-hermetic single-stage compressors on the high-stage side.
【００１１】さらに、前記他の目的は圧縮機の吐出圧力
と中間圧力との差圧を利用して冷凍機油を供給する差圧
給油方式を採り入れた多段圧縮冷凍サイクルの圧縮機の
起動方法において、多段の圧縮機のうちの圧縮段数の高
い圧縮機の起動を優先するとともに、圧縮段数の高い圧
縮機が全負荷運転状態に移行後、直近でかつ上流側の圧
縮機から順次起動して行くことにより、達成される。Still another object of the present invention is to provide a compressor start-up method for a multi-stage compression refrigeration cycle, which adopts a differential pressure oil supply system for supplying refrigerating machine oil by utilizing the differential pressure between the discharge pressure and the intermediate pressure of the compressor. Prioritize the startup of the compressor with the highest number of compression stages in the multi-stage compressor, and start the compressor closest to the upstream side in sequence after the compressor with the highest number of compression stages shifts to the full-load operation state. Is achieved by
【００１２】そして、前記他の目的は前記多段の圧縮機
における低段側の圧縮機に容量制御機構を有する場合に
は、この低段側の圧縮機における容量制御運転から全負
荷運転に移動する時間を、常に高段側の圧縮機の全負荷
運転状態の時間帯とすることによって、達成される。[0012] Further, in the case where the compressor on the lower stage side of the multi-stage compressor has a capacity control mechanism, the other purpose is to shift from the capacity control operation of the compressor on the low stage side to the full load operation. This is achieved by always setting the time to the time zone of the full-load operation state of the high-stage compressor.
【００１３】[0013]
【作用】本発明多段圧縮冷凍サイクルでは、圧縮機とし
て、第一段の圧縮機構と第二段の圧縮機構とを一体化し
たコンパウンド型の半密閉二段圧縮機と、第三段目の圧
縮機構を有する半密閉単段圧縮機とを組み合わせた三段
圧縮方式を採り入れているので、蒸発温度が−８０〜−
６５℃の超低温領域において使用可能で、しかも消費電
力当たりの冷却能力の低下をきたさない冷凍サイクルと
して、圧縮機部分の小型化を図ることができるし、さら
には各々の圧縮機に電動機を内蔵し、各電動機の冷却に
冷媒冷却方式を採り入れているので、電動機を冷却する
ための冷却水循環装置や通風装置が不要となり、また電
動機内蔵のため、軸封装置も不要となり、さらに各圧縮
機の軸受への給油に、圧縮機の吐出圧力との中間圧力と
の差圧を利用して冷凍機油を供給する差圧給油方式を採
り入れているので、油ポンプ等の強制潤滑装置も不要と
なり、したがって冷凍サイクルの大幅な小型化およびメ
ンテナンス作業の簡素化を図ることができる。In the multi-stage compression refrigeration cycle of the present invention, as the compressor, a compound type semi-hermetic two-stage compressor in which the first-stage compression mechanism and the second-stage compression mechanism are integrated, and the third-stage compression Since a three-stage compression system that combines a semi-hermetic single-stage compressor with a mechanism is adopted, the evaporation temperature is -80 to-
As a refrigeration cycle that can be used in the ultra-low temperature range of 65 ° C and that does not reduce the cooling capacity per power consumption, it is possible to reduce the size of the compressor part, and further, an electric motor is built into each compressor. Since a refrigerant cooling system is adopted to cool each electric motor, a cooling water circulation device and a ventilation device for cooling the electric motor are not required.Because the electric motor is built-in, a shaft sealing device is also unnecessary. Since the differential pressure oil supply system that supplies the refrigeration oil by utilizing the differential pressure between the discharge pressure and the intermediate pressure of the compressor is adopted for the oil supply to the It is possible to greatly reduce the size of the cycle and simplify the maintenance work.
【００１４】また、本発明多段圧縮冷凍サイクルではブ
ースタ側に前記半密閉二段圧縮機を複数台設置し、高段
側に前記半密閉単段圧縮機を１台設置しており、または
ブースタ側に前記半密閉二段圧縮機を１台設置し、高段
側に前記半密閉単段圧縮機を複数台設置しているので、
より一層冷凍能力を向上させることができる。In the multistage compression refrigeration cycle of the present invention, a plurality of the semi-hermetic two-stage compressors are installed on the booster side, and one semi-hermetic single-stage compressor is installed on the high stage side, or the booster side. Since one of the semi-hermetic two-stage compressors is installed in, and a plurality of the semi-hermetic single-stage compressors are installed on the high stage side,
The refrigerating capacity can be further improved.
【００１５】そして、本発明多段圧縮冷凍サイクルの起
動方法では、前記多段の圧縮機のうちの圧縮段数の高い
圧縮機の起動を優先的に行い、圧縮段数の高い圧縮機が
全負荷運転状態、つまり高段側圧縮機が１００％ロード
運転移行後、直近でかつ上流側の圧縮機から順次起動し
て行くようにしているので、圧縮機の起動直後から安定
状態に至るまでの過渡状態における中間圧力の異常上昇
を抑制することが可能となり、給油性能の低下および圧
縮機の軸受の寿命低下を防止することができる。In the multistage compression refrigeration cycle starting method of the present invention, the compressor having the higher compression stage number among the multistage compressors is preferentially started so that the compressor having the higher compression stage number is in the full load operation state. In other words, after the 100% load operation of the high-stage compressor, it is arranged to start sequentially from the most recent and upstream compressor, so that the intermediate state in the transient state from immediately after the start of the compressor to the stable state is reached. It is possible to suppress an abnormal rise in pressure, and it is possible to prevent a decrease in oil supply performance and a reduction in the life of the compressor bearing.
【００１６】また、本発明多段圧縮冷凍サイクルの起動
方法では、低段側の圧縮機に容量制御機構を有する場合
には、この低段側の圧縮機における容量制御運転から全
負荷運転に移行する時間を、常に高段側の圧縮機の全負
荷運転状態の時間帯としているので、この起動方法によ
っても、圧縮機の起動直後から安定状態に至るまでの過
渡状態における中間圧力の異常上昇を抑制し、給油性能
の低下および圧縮機の軸受の寿命低下を防止することが
できる。Further, in the starting method of the multistage compression refrigeration cycle of the present invention, when the compressor on the lower stage side has a capacity control mechanism, the capacity control operation of the compressor on the lower stage side is shifted to the full load operation. Since the time is always set to the time zone of the full-load operation state of the high-stage compressor, this startup method also suppresses the abnormal rise of the intermediate pressure in the transient state from immediately after the startup of the compressor to the stable state. However, it is possible to prevent deterioration of oil supply performance and reduction of life of the bearing of the compressor.
【００１７】[0017]
【実施例】以下、本発明の一実施例について、図１，図
２により説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.
【００１８】図１は三段圧縮冷凍サイクルの系統図であ
り、この図１中で実線の矢印は冷媒および冷凍機油の流
れ方向を示す。図２は多段圧縮冷凍サイクルの各圧縮機
の起動時から安定状態に移行するまでの圧力特性図であ
る。FIG. 1 is a system diagram of a three-stage compression refrigeration cycle. In FIG. 1, solid arrows indicate the flow directions of refrigerant and refrigerating machine oil. FIG. 2 is a pressure characteristic diagram from the start of each compressor of the multi-stage compression refrigeration cycle to the transition to a stable state.
【００１９】その図１に示す三段圧縮冷凍サイクルは、
半密閉二段圧縮機１と、半密閉単段圧縮機２と、油分離
器３と、凝縮器７と、第一過冷却器用膨張弁９を有する
第一過冷却器８と、第二過冷却器用膨張弁１１を有する
第二過冷却器１０と、主膨張弁１２と、蒸発器１３と、
前記分離器３に接続された油タンク４と、油冷却器５
と、油濾過器６と、前記圧縮機の制御回路（図示せず）
とを備えて構成されている。The three-stage compression refrigeration cycle shown in FIG.
Semi-hermetic two-stage compressor 1, semi-hermetic single-stage compressor 2, oil separator 3, condenser 7, first subcooler 8 having first subcooler expansion valve 9, and second supercooler A second subcooler 10 having a cooler expansion valve 11, a main expansion valve 12, and an evaporator 13,
An oil tank 4 connected to the separator 3 and an oil cooler 5
An oil filter 6 and a control circuit for the compressor (not shown)
And is configured.
【００２０】前記半密閉二段圧縮機１には、第一段の圧
縮機構と第二段の圧縮機構とを一体化したコンパウンド
型の例えばスクリュー圧縮機が用いられており、この半
密閉二段圧縮機１はブースタ側に設置されている。ま
た、この半密閉二段圧縮機１の低段側の圧縮機構である
第一段の圧縮機構側に、吸入ガスをバイパスして容量制
御を行う容量制御機構を有している。The semi-hermetic two-stage compressor 1 uses a compound type screw compressor, for example, which is a combination of a first-stage compression mechanism and a second-stage compression mechanism. The compressor 1 is installed on the booster side. Further, on the side of the first-stage compression mechanism, which is the compression mechanism on the low-stage side of the semi-hermetic two-stage compressor 1, there is provided a capacity control mechanism for bypassing the suction gas and controlling the capacity.
【００２１】前記半密閉単段圧縮機２には、三段目の圧
縮機構を有する例えばスクリュー圧縮機が用いられてお
り、この半密閉単段圧縮機２は高段側に設置されてい
る。As the semi-hermetic single-stage compressor 2, for example, a screw compressor having a third-stage compression mechanism is used, and the semi-hermetic single-stage compressor 2 is installed on the high stage side.
【００２２】前記半密閉二段圧縮機１および半密閉単段
圧縮機２には、それぞれ電動機（図示せず）が内蔵され
ている。各電動機は、冷媒冷却方式により冷却されるよ
うになっている。各圧縮機の軸受等へは、圧縮機の吐出
圧力と中間圧力との差圧を利用して冷凍器油を供給する
差圧給油方式により給油するようになっている。なお、
第一段目の圧縮後の圧力を第一中間圧力と称し、第二段
目の圧縮後の圧力を第二中間圧力と称する。An electric motor (not shown) is built in each of the semi-hermetic two-stage compressor 1 and the semi-hermetic single-stage compressor 2. Each electric motor is cooled by a refrigerant cooling system. The bearing and the like of each compressor are lubricated by a differential pressure lubrication system that supplies refrigerating machine oil by utilizing the differential pressure between the discharge pressure of the compressor and the intermediate pressure. In addition,
The pressure after compression in the first stage is referred to as the first intermediate pressure, and the pressure after compression in the second stage is referred to as the second intermediate pressure.
【００２３】前記圧縮機の制御回路は、限時継電器を有
し、常に高段側の圧縮機が全負荷運転状態となった信号
を検知したのちに、直近でかつ上流側の圧縮機から運転
を開始して行くように構成され、また低段側の圧縮機に
容量制御機構を有する場合には、その低段側の圧縮機に
おける容量制御運転から全負荷運転に移動する時間を、
常に高段側の圧縮機が全負荷運転状態となった信号を検
知後の時間帯に設定している。The control circuit of the compressor has a time delay relay, and after detecting a signal that the high-stage side compressor is in a full-load operation state at all times, the compressor is operated immediately from the upstream side. If it is configured to start and the compressor on the low stage side has a capacity control mechanism, the time to move from the capacity control operation to the full load operation on the compressor on the low stage side,
The high-stage compressor is always set to the time zone after detection of the signal indicating that the compressor is operating at full load.
【００２４】なお、前記圧縮機は低段側であるブースタ
側に半密閉二段圧縮機１を複数台設置し、高段側に半密
閉単段圧縮機２を１台設置してもよく、またはブースタ
側に半密閉二段圧縮機１を１台設置し、高段側に半密閉
単段圧縮機２を複数台設置してもよい。In the compressor, a plurality of semi-hermetic two-stage compressors 1 may be installed on the booster side, which is the low stage side, and one semi-hermetic single-stage compressor 2 may be installed on the high stage side. Alternatively, one semi-hermetic two-stage compressor 1 may be installed on the booster side, and a plurality of semi-hermetic single-stage compressors 2 may be installed on the high stage side.
【００２５】次に、前記実施例の三段圧縮冷凍サイクル
の動作と、圧縮機の起動方法について説明する。Next, the operation of the three-stage compression refrigeration cycle of the above embodiment and the method of starting the compressor will be described.
【００２６】まず、冷媒は半密閉二段圧縮機１の第一段
および第二段の圧縮機構により二回圧縮されたのち、半
密閉単段圧縮機２の第三段の圧縮機構により三回目の圧
縮が行われ、高温高圧の冷媒ガスとなって吐出される。
なお、この冷媒ガスには冷凍機油が含まれている。First, the refrigerant is compressed twice by the first-stage and second-stage compression mechanisms of the semi-hermetic two-stage compressor 1, and then the third time by the third stage compression mechanism of the semi-hermetic single-stage compressor 2. Is compressed and discharged as high-temperature high-pressure refrigerant gas.
This refrigerant gas contains refrigerating machine oil.
【００２７】前記半密閉単段圧縮機２から吐出された冷
媒ガスは、油分離器３に送られ、この油分離器３により
冷媒ガスと冷凍機油に分離され、分離された冷媒ガスは
凝縮器７に送られ、冷凍機油は油タンク４に送られる。The refrigerant gas discharged from the semi-hermetic single-stage compressor 2 is sent to the oil separator 3, and is separated into the refrigerant gas and the refrigerating machine oil by the oil separator 3, and the separated refrigerant gas is condensed. 7, the refrigerating machine oil is sent to the oil tank 4.
【００２８】前記凝縮器７に送り込まれた冷媒ガスは、
この凝縮器７により凝縮され、高圧の液冷媒となり、第
一過冷却器８に送られる。The refrigerant gas sent to the condenser 7 is
It is condensed by the condenser 7, becomes a high-pressure liquid refrigerant, and is sent to the first subcooler 8.
【００２９】前記第一過冷却器８に送り込まれた高圧の
液冷媒は、この第一過冷却器８により過冷却されて液温
が下げられ、第一過冷却器８を通過後に二方向に分岐さ
れる。分岐された一方の液冷媒は第二過冷却器１０に向
かう主流液となり、他方の液冷媒は第一過冷却器用膨張
弁９により湿りガスとなり、半密閉二段圧縮機１に吸入
される。The high-pressure liquid refrigerant sent to the first subcooler 8 is subcooled by the first subcooler 8 to lower the liquid temperature, and after passing through the first subcooler 8, it is bidirectionally moved. Branched. One of the branched liquid refrigerant becomes a mainstream liquid toward the second subcooler 10, and the other liquid refrigerant becomes a wet gas by the first subcooler expansion valve 9 and is sucked into the semi-hermetic two-stage compressor 1.
【００３０】前記半密閉二段圧縮機１に吸入された湿り
ガスは半密閉二段圧縮機１より吐出された高温高圧のガ
スと混合され、このガスを冷却してから半密閉単段圧縮
機２に吸入される。The moist gas sucked into the semi-hermetic two-stage compressor 1 is mixed with the high-temperature and high-pressure gas discharged from the semi-hermetic two-stage compressor 1, and the semi-hermetic single-stage compressor is cooled. Inhaled to 2.
【００３１】一方、前記第一過冷却器８から第二過冷却
器１０に流入した主流液は、この第二過冷却器１０によ
りさらに過冷却され、第二過冷却器１０を通過後、二方
向に分岐される。分岐された液冷媒の一方は主膨張弁１
２に向かう主流液となり、他方は第二過冷却器用膨張弁
１１により湿りガスとなり、半密閉二段圧縮機１の中間
ケーシング部に吸入される。On the other hand, the mainstream liquid flowing from the first subcooler 8 into the second subcooler 10 is further subcooled by the second subcooler 10 and, after passing through the second subcooler 10, is It is branched in the direction. One of the branched liquid refrigerant is the main expansion valve 1
It becomes the main stream liquid toward 2, and the other becomes the wet gas by the expansion valve 11 for the second subcooler, and is sucked into the intermediate casing part of the semi-hermetic two-stage compressor 1.
【００３２】前記半密閉二段圧縮機１の中間ケーシング
に吸入された湿りガスは、半密閉二段圧縮機１内で第一
段の圧縮機構により圧縮された吐出ガスと混合され、圧
縮機に内蔵の電動機を冷却したのち、第二段の圧縮機構
に吸入され、圧縮される。The moist gas sucked into the intermediate casing of the semi-hermetic two-stage compressor 1 is mixed with the discharge gas compressed by the first-stage compression mechanism in the semi-hermetic two-stage compressor 1 to be supplied to the compressor. After cooling the built-in electric motor, it is sucked into the second-stage compression mechanism and compressed.
【００３３】前記主膨張弁１２に流入した主流液は、こ
の主膨張弁１２により低圧の湿りガスとなり、蒸発器１
３に送られ、この蒸発器１３内で蒸発して冷却作用を行
ったのち、半密閉二段圧縮機１に吸入される。The main flow liquid flowing into the main expansion valve 12 becomes a low-pressure wet gas by the main expansion valve 12, and the evaporator 1
After being sent to the evaporator 3, the evaporator 13 evaporates and performs a cooling function, and then is sucked into the semi-hermetic two-stage compressor 1.
【００３４】そして、前記油分離器３により冷媒ガスと
分離された冷凍機油は、油タンク４にいったん貯えら
れ、ついで油冷却器５により冷却され、油濾過器６を経
て半密閉二段圧縮機１および半密閉単段圧縮機２内の軸
受等に差圧給油方式により給油される。The refrigerating machine oil separated from the refrigerant gas by the oil separator 3 is temporarily stored in the oil tank 4, then cooled by the oil cooler 5, and passed through the oil filter 6 to the semi-hermetic two-stage compressor. The bearings in 1 and the semi-hermetic single-stage compressor 2 are lubricated by a differential pressure lubrication system.
【００３５】ところで、前記圧縮機の起動順序として
は、まず第三段目の圧縮機構を有する半密閉単段圧縮機
２を起動する。この半密閉単段圧縮機２を起動後、１０
０％ロード状態となった信号を検知したのちに、圧縮機
の制御回路の限時継電器の動作により、限時継電器の設
定時間後に半密閉二段圧縮機１を起動する。この半密閉
二段圧縮機１はコンパウンド型の圧縮機で、第一段の圧
縮機構と第二段の圧縮機構とは同時起動となるが、低段
側の圧縮機構である第一段の圧縮機構の容量制御機構
は、半密閉単段圧縮機２の起動直後からの制御回路の限
時継電器の動作により、限時継電器の設定時間帯にの
み、つまり半密閉単段圧縮機２が１００％ロード状態と
なったときにのみ、第一段の圧縮機構が動作し、容量制
御運転を実施する。As for the order of starting the compressors, first, the semi-hermetic single-stage compressor 2 having the third-stage compression mechanism is started. After starting this semi-hermetic single-stage compressor 2, 10
After the 0% load signal is detected, the semi-hermetic two-stage compressor 1 is started after the set time of the time delay relay by the operation of the time delay relay in the control circuit of the compressor. The semi-hermetic two-stage compressor 1 is a compound type compressor, and the first-stage compression mechanism and the second-stage compression mechanism are simultaneously activated, but the first-stage compression mechanism which is the lower-stage compression mechanism. The capacity control mechanism of the mechanism is that the semi-hermetic single-stage compressor 2 is in a 100% loaded state only during the set time zone of the time-limiting relay by the operation of the time relay of the control circuit immediately after starting the semi-hermetic single-stage compressor 2. Only when this occurs, the first-stage compression mechanism operates and the capacity control operation is performed.
【００３６】各圧縮機の起動時から安定状態に移行する
までの圧力特性は、図２に示すようになる。この図２に
おいて、実線で示す圧力特性は本発明起動方法による場
合の挙動であり、第一中間圧力は線図（ハ），第二中間
圧力は線図（イ）のごとき推移となり、圧縮機の吐出圧
力（高圧圧力）と第一中間圧力との差圧ΔＰ1 ，同吐出
圧力と第二中間圧力との差圧ΔＰ2 とも十分大きく確保
することができる。したがって、この差圧ΔＰ1，ΔＰ2
を利用して圧縮機の軸受等への給油を安定的に行うこと
ができ、圧縮機の起動直後より安定状態に至るまでの過
渡状態における中間圧力の異常上昇を抑制し、給油性能
の低下および軸受寿命の低下を防止することができる。The pressure characteristics from the start of each compressor to the transition to the stable state are as shown in FIG. In FIG. 2, the pressure characteristic indicated by the solid line is the behavior in the case of the starting method of the present invention. The first intermediate pressure changes as shown in the diagram (c) and the second intermediate pressure changes as shown in the diagram (a). differential pressure [Delta] P 1 of the discharge pressure (the high pressure) and the first intermediate pressure, also the pressure difference [Delta] P 2 of the same discharge pressure and the second intermediate pressure can be ensured sufficiently large. Therefore, this differential pressure ΔP 1 , ΔP 2
Can be used to stably supply oil to the bearings of the compressor, suppress an abnormal increase in intermediate pressure in the transient state from immediately after the compressor is started until it reaches a stable state, and reduce oil supply performance. It is possible to prevent the bearing life from being shortened.
【００３７】図２に破線で示す圧力特性は、従来の起動
方法による場合の挙動であり、第一中間圧力は線図
（ニ），第二中間圧力は線図（ロ）のごとくとなり、圧
縮機の吐出圧力と第一中間圧力との差圧ΔＰ1′ ，同吐
出圧力と第二中間圧力との差圧ΔＰ2′ とも、前記ΔＰ
1，ΔＰ2に比較して小さく、圧縮機の軸受等への給油状
態が不安定となることが分かる。The pressure characteristic shown by the broken line in FIG. 2 is the behavior in the case of the conventional starting method. The first intermediate pressure is as shown in the diagram (d) and the second intermediate pressure is as shown in the diagram (b). The pressure difference ΔP 1 ′ between the discharge pressure of the machine and the first intermediate pressure and the pressure difference ΔP 2 ′ between the discharge pressure and the second intermediate pressure are both
It is smaller than 1 and ΔP 2 , and it can be seen that the state of oil supply to the bearings of the compressor becomes unstable.
【００３８】[0038]
【発明の効果】以上説明した本発明の請求項１記載の発
明によれば、圧縮機として、第一段の圧縮機構と第二段
の圧縮機構とを一体化したコンパウンド型の半密閉二段
圧縮機と、第三段目の圧縮機構を有する半密閉単段圧縮
機とを組み合わせた三段圧縮方式を採り入れているの
で、蒸発温度が−８０〜−６５℃の超低温領域において
使用可能で、しかも消費電力当たりの冷却能力の低下を
きたさない冷凍サイクルとして、圧縮機部分の小型化を
図ることができるし、さらには各々の圧縮機に電動機を
内蔵し、各電動機の冷却に冷媒冷却方式を採り入れてい
るので、電動機を冷却するための冷却水循環装置や通風
装置が不要となり、また電動機内蔵のため、軸封装置も
不要となり、さらに各圧縮機の軸受への給油に、圧縮機
の吐出圧力と中間圧力との差圧を利用して冷凍機油を供
給する差圧給油方式を採り入れているので、油ポンプ等
の強制潤滑装置も不要となり、したがって冷凍サイクル
の大幅な小型化およびメンテナンス作業の簡素化を図り
得る効果がある。According to the invention described in claim 1 of the present invention described above, as a compressor, a compound type semi-hermetic two-stage in which a first-stage compression mechanism and a second-stage compression mechanism are integrated. Since a three-stage compression method that combines a compressor and a semi-hermetic single-stage compressor having a third-stage compression mechanism is adopted, it can be used in an ultra-low temperature range where the evaporation temperature is -80 to -65 ° C. Moreover, as a refrigeration cycle that does not reduce the cooling capacity per power consumption, it is possible to reduce the size of the compressor part.Furthermore, each compressor has a built-in electric motor, and a refrigerant cooling system is used to cool each electric motor. Since it is adopted, no cooling water circulation device or ventilation device for cooling the electric motor is required.Since the electric motor is built in, a shaft sealing device is also unnecessary. And intermediate pressure Since a differential pressure lubrication system that supplies refrigerating machine oil by utilizing the differential pressure between and is not required, a forced lubrication device such as an oil pump is not required, and therefore the refrigeration cycle is greatly downsized and maintenance work is simplified. There is an effect to obtain.
【００３９】また、本発明の請求項２記載の発明によれ
ば、ブースタ側に前記半密閉二段圧縮機を複数台設置
し、高段側に前記半密閉単段圧縮機を１台設置してお
り、さらに、請求項３記載の発明によれば、ブースタ側
に前記半密閉二段圧縮機を１台設置し、高段側に前記半
密閉単段圧縮機を複数台設置しているので、より一層冷
凍能力を向上させ得る効果がある。According to the second aspect of the present invention, a plurality of the semi-hermetic two-stage compressors are installed on the booster side, and one semi-hermetic single-stage compressor is installed on the high stage side. Further, according to the invention of claim 3, one of the semi-hermetic two-stage compressors is installed on the booster side, and a plurality of the semi-hermetic single-stage compressors is installed on the high stage side. Therefore, there is an effect that the refrigerating capacity can be further improved.
【００４０】さらに、本発明の請求項４記載の発明によ
れば、前記多段の圧縮機のうちの圧縮段数の高い圧縮機
の起動を優先的に行い、圧縮段数の高い圧縮機が全負荷
運転状態に移動後、直近でかつ上流側の圧縮機から順次
起動して行くようにしているので、圧縮機の起動直後か
ら安定状態に至るまでの過渡状態における中間圧力の上
昇を抑制することが可能となり、給油性能の低下および
圧縮機の軸受の寿命低下を防止し得る効果がある。Further, according to the invention described in claim 4 of the present invention, of the multi-stage compressors, the compressor having a high compression stage is preferentially started, and the compressor having a high compression stage operates at full load. After moving to the state, the compressor is started sequentially from the most recent and upstream compressor, so it is possible to suppress the rise of intermediate pressure in the transient state from immediately after the compressor starts to the stable state. Therefore, there is an effect that it is possible to prevent the deterioration of the lubrication performance and the life of the bearing of the compressor.
【００４１】そして、本発明の請求項５記載の発明によ
れば、低段側の圧縮機に容量制御機構を有する場合に
は、この低段側の圧縮機における容量制御運転から全負
荷運転に移行する時間を、常に高段側の圧縮機の全負荷
運転状態の時間帯としているので、この起動方法によっ
ても、圧縮機の起動直後から安定状態に至るまでの過渡
状態における中間圧力の上昇を抑制し、給油性能の低下
および圧縮機の軸受の寿命低下を防止し得る効果があ
る。According to the fifth aspect of the present invention, when the compressor on the low stage side has a capacity control mechanism, the capacity control operation of the compressor on the low stage side is changed to full load operation. Since the transition time is always set to the time zone of the full-load operation state of the high-stage compressor, this startup method also increases the intermediate pressure in the transient state from immediately after the startup of the compressor to the stable state. There is an effect that it is possible to suppress and prevent deterioration of oil supply performance and reduction of life of the bearing of the compressor.
【図１】本発明の一実施例を示す三段圧縮冷凍サイクル
の系統図である。FIG. 1 is a system diagram of a three-stage compression refrigeration cycle showing an embodiment of the present invention.
【図２】多段圧縮冷凍サイクルの各圧縮機の起動時から
安定状態に移行するまでの圧力特性図である。FIG. 2 is a pressure characteristic diagram from the time of starting each compressor of the multi-stage compression refrigeration cycle to a stable state.
【図３】従来の多段圧縮冷凍サイクルの系統図である。FIG. 3 is a system diagram of a conventional multistage compression refrigeration cycle.
１…半密閉二段圧縮機、２…半密閉単段圧縮機、３…油
分離器、４…油タンク、５…油冷却器、６…油濾過器、
７…凝縮器、８…第一過冷却器、９…第一過冷却器用膨
張弁、１０…第二過冷却器、１１…第二過冷却器用膨張
弁、１２…主膨張弁、１３…蒸発器。1 ... Semi-hermetic two-stage compressor, 2 ... Semi-hermetic single-stage compressor, 3 ... Oil separator, 4 ... Oil tank, 5 ... Oil cooler, 6 ... Oil filter,
7 ... Condenser, 8 ... 1st subcooler, 9 ... 1st subcooler expansion valve, 10 ... 2nd subcooler, 11 ... 2nd subcooler expansion valve, 12 ... Main expansion valve, 13 ... Evaporation vessel.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 加瀬沢 実 静岡県清水市村松390番地 株式会社日立 製作所清水工場内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Kasezawa 390 Muramatsu, Shimizu City, Shizuoka Prefecture Hitachi Ltd. Shimizu Plant
Claims (5)
と、主膨張弁と、蒸発器とを接続してなる冷凍サイクル
において、前記圧縮機として、第一段の圧縮機構と第二
段の圧縮機構とを一体化したコンパウンド型の半密閉二
段圧縮機と、第三段目の圧縮機構を有する半密閉単段圧
縮機とを組み合わせた三段圧縮方式を採り入れ、各々の
圧縮機に電動機を内蔵するとともに、各電動機の冷却に
冷媒冷却方式を採り入れ、各圧縮機の軸受への給油に、
圧縮機の吐出圧力と中間圧力との差圧を利用して冷凍機
油を供給する差圧供給方式を採り入れたことを特徴とす
る多段圧縮冷凍サイクル。1. A refrigerating cycle in which at least a compressor, a condenser, a subcooler, a main expansion valve and an evaporator are connected to each other, and the first stage compression mechanism and the second compression mechanism are used as the compressor. Adopted a three-stage compression system that combines a compound type semi-hermetic two-stage compressor integrated with a three-stage compression mechanism and a semi-hermetic single-stage compressor having a third-stage compression mechanism, and each compressor In addition to incorporating an electric motor in the, adopting a refrigerant cooling system to cool each electric motor, to lubricate the bearings of each compressor,
A multi-stage compression refrigeration cycle, characterized by adopting a differential pressure supply system for supplying refrigerating machine oil by utilizing the differential pressure between the discharge pressure of the compressor and the intermediate pressure.
台設置し、高段側に前記半密閉単段圧縮機を１台設置し
たことを特徴とする請求項１記載の多段圧縮冷凍サイク
ル。2. The multi-stage compression refrigeration system according to claim 1, wherein a plurality of said semi-hermetic two-stage compressors are installed on the booster side, and one said semi-hermetic single-stage compressor is installed on the high stage side. cycle.
設置し、高段側に前記半密閉単段圧縮機を複数台設置し
たことを特徴とする請求項１記載の多段圧縮冷凍サイク
ル。3. A multistage compression refrigeration system according to claim 1, wherein one semi-hermetic two-stage compressor is installed on the booster side and a plurality of semi-hermetic single-stage compressors are installed on the high stage side. cycle.
冷却器と、主膨張弁と、蒸発器とを接続し、かつ各段の
圧縮機の軸受への給油に、圧縮機の吐出圧力と中間圧力
との差圧を利用して冷凍機油を供給する差圧給油方式を
採り入れた多段冷凍サイクルの圧縮機の起動方法におい
て、前記多段の圧縮機のうちの圧縮段数の高い圧縮機の
起動を優先するとともに、圧縮段数の高い圧縮機が全負
荷運転状態に移動後、直近でかつ上流側の圧縮機から順
次起動して行くことを特徴とする多段圧縮冷凍サイクル
の起動方法。4. A compressor discharge for connecting at least a multi-stage compressor, a condenser, a subcooler, a main expansion valve, and an evaporator, and for supplying oil to the bearings of each stage compressor. In a method of starting a compressor of a multi-stage refrigeration cycle that adopts a differential pressure oil supply system that supplies a refrigerating machine oil using a differential pressure between a pressure and an intermediate pressure, in a compressor with a high compression stage number among the multi-stage compressors. A start-up method for a multi-stage compression refrigeration cycle, characterized in that start-up is prioritized, and a compressor with a high number of compression stages is moved to a full-load operation state and then sequentially started from the most recent upstream compressor.
に容量制御機構を有する場合には、この低段側の圧縮機
における容量制御運転から全負荷運転に移行する時間
を、常に高段側の圧縮機の全負荷運転状態の時間帯とす
ることを特徴とする請求項４記載の多段圧縮冷凍サイク
ルの起動方法。5. When the compressor on the low stage side of the multi-stage compressor has a capacity control mechanism, the time for shifting from the capacity control operation to the full load operation on the compressor on the low stage side is always high. The method for starting a multi-stage compression refrigeration cycle according to claim 4, wherein the time zone of full-load operation of the stage compressor is set.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12710292A JPH05322334A (en) | 1992-05-20 | 1992-05-20 | Multi-stage compression freezing cycle and its actuating method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12710292A JPH05322334A (en) | 1992-05-20 | 1992-05-20 | Multi-stage compression freezing cycle and its actuating method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05322334A true JPH05322334A (en) | 1993-12-07 |
Family
ID=14951650
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12710292A Pending JPH05322334A (en) | 1992-05-20 | 1992-05-20 | Multi-stage compression freezing cycle and its actuating method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05322334A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6460371B2 (en) | 2000-10-13 | 2002-10-08 | Mitsubishi Heavy Industries, Ltd. | Multistage compression refrigerating machine for supplying refrigerant from subcooler to cool rotating machine and lubricating oil |
| WO2005024313A1 (en) * | 2003-09-05 | 2005-03-17 | Daikin Industries, Ltd. | Freezer device |
| JP2010156536A (en) * | 2008-12-05 | 2010-07-15 | Daikin Ind Ltd | Refrigeration device |
| CN104792052A (en) * | 2015-04-29 | 2015-07-22 | 上海海洋大学 | Novel ultralow-temperature compression refrigerating system |
| CN108489130A (en) * | 2018-06-06 | 2018-09-04 | 深圳市派沃新能源科技股份有限公司 | A kind of screw single machine three stage compression heat pump heating system and control method |
-
1992
- 1992-05-20 JP JP12710292A patent/JPH05322334A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6460371B2 (en) | 2000-10-13 | 2002-10-08 | Mitsubishi Heavy Industries, Ltd. | Multistage compression refrigerating machine for supplying refrigerant from subcooler to cool rotating machine and lubricating oil |
| WO2005024313A1 (en) * | 2003-09-05 | 2005-03-17 | Daikin Industries, Ltd. | Freezer device |
| EP1669694A1 (en) * | 2003-09-05 | 2006-06-14 | Daikin Industries, Ltd. | Freezer device |
| EP1669694A4 (en) * | 2003-09-05 | 2009-04-08 | Daikin Ind Ltd | Freezer device |
| US7640762B2 (en) | 2003-09-05 | 2010-01-05 | Daikin Industries, Ltd. | Refrigeration apparatus |
| JP2010156536A (en) * | 2008-12-05 | 2010-07-15 | Daikin Ind Ltd | Refrigeration device |
| CN104792052A (en) * | 2015-04-29 | 2015-07-22 | 上海海洋大学 | Novel ultralow-temperature compression refrigerating system |
| CN108489130A (en) * | 2018-06-06 | 2018-09-04 | 深圳市派沃新能源科技股份有限公司 | A kind of screw single machine three stage compression heat pump heating system and control method |
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