JP2004251492A - Refrigerant cycle device - Google Patents

Refrigerant cycle device Download PDF

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Publication number
JP2004251492A
JP2004251492A JP2003040170A JP2003040170A JP2004251492A JP 2004251492 A JP2004251492 A JP 2004251492A JP 2003040170 A JP2003040170 A JP 2003040170A JP 2003040170 A JP2003040170 A JP 2003040170A JP 2004251492 A JP2004251492 A JP 2004251492A
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Japan
Prior art keywords
refrigerant
compressor
pressure
circuit
bypass circuit
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Pending
Application number
JP2003040170A
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Japanese (ja)
Inventor
Kenzo Matsumoto
兼三 松本
Shigeya Ishigaki
茂弥 石垣
Haruhisa Yamazaki
晴久 山崎
Masaji Yamanaka
正司 山中
Kazuaki Fujiwara
一昭 藤原
Tsunehisa Yumoto
恒久 湯本
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Sanyo Electric Co Ltd
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Sanyo Electric Co Ltd
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Priority to JP2003040170A priority Critical patent/JP2004251492A/en
Publication of JP2004251492A publication Critical patent/JP2004251492A/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/30—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
    • F04C18/34—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members
    • F04C18/356—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the outer member
    • F04C18/3562—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the outer member the inner and outer member being in contact along one line or continuous surfaces substantially parallel to the axis of rotation
    • F04C18/3564—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the outer member the inner and outer member being in contact along one line or continuous surfaces substantially parallel to the axis of rotation the surfaces of the inner and outer member, forming the working space, being surfaces of revolution
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
    • F04C23/001—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids of similar working principle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
    • F04C23/008—Hermetic pumps
    • 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
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/10—Compression machines, plants or systems with non-reversible cycle with multi-stage compression
    • 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
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/06—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide
    • F25B2309/061—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide with cycle highest pressure above the supercritical pressure
    • 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
    • F25B2400/04—Refrigeration circuit bypassing means
    • 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
    • F25B2500/00—Problems to be solved
    • F25B2500/26—Problems to be solved characterised by the startup of the refrigeration cycle
    • 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
    • F25B40/00—Subcoolers, desuperheaters or superheaters
    • 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
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
    • F25B9/008—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant being carbon dioxide

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerant cycle device for avoiding the occurrence of inconveniences due to abnormally high pressure. <P>SOLUTION: The refrigerant cycle device comprises a bypass circuit 170 communicating a refrigerant discharge pipe 96 on the high pressure side of a refrigerant circuit with an intermediate cooling circuit 150 as an intermediate pressure region and a capillary tube 172 and a bypass valve 174 as pressure reducing means provided in the bypass circuit 170. In starting a compressor 10, a flow path in the bypass circuit 170 is opened by the bypass valve 174 connected to a control device, not illustrated. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、コンプレッサ、ガスクーラ、絞り手段及び蒸発器を順次接続して冷媒回路が構成される冷媒サイクル装置に関するものである。
【０００２】
【従来の技術】
従来のこの種冷媒サイクル装置は、ロータリコンプレッサ（コンプレッサ）、ガスクーラ、絞り手段（膨張弁等）及び蒸発器等を順次環状に配管接続して冷媒サイクル（冷媒回路）が構成されている。そして、ロータリコンプレッサの回転圧縮要素の吸込ポートから冷媒ガスがシリンダの低圧室側に吸入され、ローラとベーンの動作により圧縮が行われて高温高圧の冷媒ガスとなり、高圧室側より吐出ポート、吐出消音室を経てガスクーラに吐出される。このガスクーラにて冷媒ガスは放熱した後、絞り手段で絞られて蒸発器に供給される。そこで冷媒が蒸発し、そのときに周囲から吸熱することにより冷却作用を発揮するものであった。
【０００３】
ここで、近年では地球環境問題に対処するため、この種の冷媒サイクルにおいても、従来のフロンを用いずに自然冷媒である二酸化炭素（ＣＯ２）を冷媒として用い、高圧側を超臨界圧力として運転する遷臨界冷媒サイクルを用いた装置が開発されて来ている。
【０００４】
このような冷媒サイクル装置では、コンプレッサ内に液冷媒が戻って、液圧縮することを防ぐために、蒸発器の出口側とコンプレッサの吸込側との間の低圧側にアキュムレータを配設し、このアキュムレータに液冷媒を溜め、ガスのみをコンプレッサに吸い込ませる構成とされていた。そして、アキュムレータ内の液冷媒がコンプレッサに戻らないように絞り手段を調整していた（例えば、特許文献１参照）。
【０００５】
【特許文献１】
特公平７−１８６０２号公報
【０００６】
しかしながら、冷媒サイクルの低圧側にアキュムレータを設けることは、その分多くの冷媒充填量を必要とする。また、液バックを防止するためには絞り手段の開度を小さくし、或いは、アキュムレータの容量を拡大しなければならず、冷却能力の低下や設置スペースの拡大を招く。そこで、係るアキュムレータを設けること無く、コンプレッサにおける液圧縮を解消するために、出願人は従来図４に示す冷媒サイクル装置の開発を試みた。
【０００７】
図４において、１０は内部中間圧型多段（２段）圧縮式ロータリコンプレッサを示しており、密閉容器１２内の駆動要素としての電動要素１４とこの電動要素１４の回転軸１６で駆動される第１の回転圧縮要素３２及び第２の回転圧縮要素３４を備えて構成されている。
【０００８】
この場合の冷媒サイクル装置の動作を説明する。コンプレッサ１０の冷媒導入管９４から吸い込まれた低圧（ＬＰ）の冷媒は、第１の回転圧縮要素３２で圧縮されて中間圧（ＭＰ）となり、密閉容器１２内に吐出される。その後、冷媒導入管９２から出て中間冷却回路１５０Ａに流入する。中間冷却回路１５０Ａはガスクーラ１５４を通過するように設けられており、そこで、空冷方式により放熱される。ここで中間圧の冷媒はガスクーラにて熱が奪われる。
【０００９】
その後、第２の回転圧縮要素３４に吸い込まれて２段目の圧縮が行われて高温高圧（ＨＰ）の冷媒ガスとなり、冷媒吐出管９６より外部に吐出される。このとき、冷媒は適切な超臨界圧力まで圧縮されている。
【００１０】
冷媒吐出管９６から吐出された冷媒ガスはガスクーラ１５４に流入し、そこで空冷方式により放熱された後、内部熱交換器１６０を通過する。冷媒はそこで蒸発器１５７を出た低圧側の冷媒に熱を奪われて更に冷却される。その後、冷媒は膨張弁１５６にて減圧され、その過程でガス／液混合状態となり、次に蒸発器１５７に流入して蒸発する。蒸発器１５７から出た冷媒は内部熱交換器１６０を通過し、そこで前記高圧側の冷媒から熱を奪って加熱される。
【００１１】
そして、内部熱交換器１６０で加熱された冷媒は冷媒導入管９４からロータリコンプレッサ１０の第１の回転圧縮要素３２内に吸い込まれるサイクルを繰り返す。このように、蒸発器１５７から出た冷媒を内部熱交換器１６０により高圧側の冷媒にて加熱することで過熱度を取ることができるようになり、低圧側にアキュムレータなどを設けること無く、コンプレッサ１０に液冷媒が吸い込まれる液バックを確実に防止し、コンプレッサ１０が液圧縮にて損傷を受ける不都合を回避することができるようになる。
【００１２】
【発明が解決しようとする課題】
一方、係る二酸化炭素を使用した冷媒サイクル装置では、高圧側の圧力が通常でも１２ＭＰａ以上まで上昇する。特に、コンプレッサを定速で運転した場合には、コンプレッサの起動時（プルダウン時）に高圧側の圧力は更に上昇し、図５に示す如く機器の設計圧（ＤＰ）を超えてしまい、機器の損傷を引き起こす恐れがある。そのため、インバータによりコンプレッサの回転数制御（容量制御）を実行するか、更にそれに加えて膨張弁の開度調整を行い、高圧側の圧力上昇を抑えて起動する必要があった。
【００１３】
本発明は、係る従来の技術的課題を解決するために成されたものであり、コンプレッサが定速で運転される場合にも高圧側圧力の異常上昇による不都合の発生を未然に回避することができる冷媒サイクル装置を提供することを目的とする。
【００１４】
【課題を解決するための手段】
即ち、本発明の冷媒サイクル装置では、冷媒回路の高圧側と中間圧領域とを連通するバイパス回路と、このバイパス回路に設けられた減圧手段及び弁装置とを備え、コンプレッサの起動時に、弁装置によりバイパス回路の流路を開放するので、高圧側の冷媒をバイパス回路から中間圧領域に逃がすことが可能となる。
【００１５】
これにより、コンプレッサが定速で運転される場合にも、起動時において高圧側圧力が異常に上昇してしまう不都合を未然に回避し、耐久性の向上と円滑な運転を確保することができるようになる。また、高圧側の冷媒はバイパス回路に設けられた減圧手段にて減圧された後、中間圧領域に流入するので、中間圧が上がり過ぎる不都合を回避することができるようになる。
【００１６】
請求項２の発明では上記発明に加えて、弁装置により、コンプレッサの起動から所定時間バイパス回路の流路を開放することを特徴とする。
【００１７】
請求項３の発明では請求項１の発明に加えて、弁装置により、コンプレッサの起動から冷媒回路内の冷媒の圧力が所定値に到達するまでバイパス回路の流路を開放することを特徴とする。
【００１８】
請求項４の発明では請求項１の発明に加えて、弁装置により、コンプレッサの起動から当該コンプレッサの駆動電流が所定値に到達するバイパス回路の流路を開放することを特徴とする。
【００１９】
請求項５の発明では請求項１の発明に加えて、弁装置により、コンプレッサの起動から冷媒回路内の冷媒の温度が所定値に到達するまでバイパス回路の流路を開放することを特徴とする。
【００２０】
請求項６の発明では上記各発明に加えて、冷媒として二酸化炭素を使用するので環境問題にも寄与することができるようになる。
【００２１】
【発明の実施の形態】
次に、図面に基づき本発明の実施形態を詳述する。図１は本発明の冷媒サイクル装置に使用するコンプレッサの実施例として、第１及び第２の回転圧縮要素３２、３４を備えた内部中間圧型多段（２段）圧縮式のロータリコンプレッサ１０の縦断面図、図２は本発明の冷媒サイクル装置の冷媒回路図である。
【００２２】
各図において、１０は二酸化炭素（ＣＯ２）を冷媒として使用する内部中間圧型多段圧縮式ロータリコンプレッサで、このコンプレッサ１０は鋼板からなる円筒状の密閉容器１２と、この密閉容器１２の内部空間の上側に配置収納された駆動要素としての電動要素１４及びこの電動要素１４の下側に配置され、電動要素１４の回転軸１６により駆動される第１の回転圧縮要素３２（１段目）及び第２の回転圧縮要素３４（２段目）から成る回転圧縮機構部１８にて構成されている。
【００２３】
密閉容器１２は底部をオイル溜めとし、電動要素１４と回転圧縮機構部１８を収納する容器本体１２Ａと、この容器本体１２Ａの上部開口を閉塞する略椀状のエンドキャップ（蓋体）１２Ｂとで構成され、且つ、このエンドキャップ１２Ｂの上面中心には円形の取付孔１２Ｄが形成されており、この取付孔１２Ｄには電動要素１４に電力を供給するためのターミナル（配線を省略）２０が取り付けられている。
【００２４】
電動要素１４は所謂磁極集中巻き式のＤＣモータであり、密閉容器１２の上部空間の内周面に沿って環状に取り付けられたステータ２２と、このステータ２２の内側に若干の間隔を設けて挿入設置されたロータ２４とからなる。このロータ２４は中心を通り鉛直方向に延びる回転軸１６に固定されている。ステータ２２は、ドーナッツ状の電磁鋼板を積層した積層体２６と、この積層体２６の歯部に直巻き（集中巻き）方式により巻装されたステータコイル２８を有している。また、ロータ２４はステータ２２と同様に電磁鋼板の積層体３０で形成され、この積層体３０内に永久磁石ＭＧを挿入して形成されている。
【００２５】
前記第１の回転圧縮要素３２と第２の回転圧縮要素３４との間には中間仕切板３６が挟持されている。即ち、第１の回転圧縮要素３２と第２の回転圧縮要素３４は、中間仕切板３６と、この中間仕切板３６の上下に配置された上シリンダ３８、下シリンダ４０と、この上下シリンダ３８、４０内を、１８０度の位相差を有して回転軸１６に設けられた上下偏心部４２、４４により偏心回転される上下ローラ４６、４８と、この上下ローラ４６、４８に当接して上下シリンダ３８、４０内をそれぞれ低圧室側と高圧室側に区画するベーン５０、５２と、上シリンダ３８の上側の開口面及び下シリンダ４０の下側の開口面を閉塞して回転軸１６の軸受けを兼用する支持部材としての上部支持部材５４及び下部支持部材５６にて構成されている。
【００２６】
一方、上部支持部材５４及び下部支持部材５６には、図示しない吸込ポートにて上下シリンダ３８、４０の内部とそれぞれ連通する吸込通路６０（上側の吸込通路は図示せず）と、一部を凹陥させ、この凹陥部を上部カバー６６、下部カバー６８にて閉塞することにより形成される吐出消音室６２、６４とが設けられている。
【００２７】
尚、吐出消音室６４と密閉容器１２内とは、上下シリンダ３８、４０や中間仕切板３６を貫通する連通路にて連通されており、連通路の上端には中間吐出管１２１が立設され、この中間吐出管１２１から第１の回転圧縮要素３２で圧縮された中間圧（ＭＰ）の冷媒ガスが密閉容器１２内に吐出される。
【００２８】
そして、冷媒としては地球環境にやさしく、可燃性及び毒性等を考慮して自然冷媒である前述した二酸化炭素（ＣＯ２）が使用され、潤滑油としてのオイルは、例えば鉱物油（ミネラルオイル）、アルキルベンゼン油、エーテル油、エステル油、ＰＡＧ（ポリアルキルグリコール）など既存のオイルが使用される。
【００２９】
密閉容器１２の容器本体１２Ａの側面には、上部支持部材５４と下部支持部材５６の吸込通路６０（上側は図示せず）、吐出消音室６２、上部カバー６６の上側（電動要素１４の下端に略対応する位置）に対応する位置に、スリーブ１４１、１４２、１４３及び１４４がそれぞれ溶接固定されている。そして、スリーブ１４１内には上シリンダ３８に冷媒ガスを導入するための冷媒導入管９２の一端が挿入接続され、この冷媒導入管９２の一端は上シリンダ３８の図示しない吸込通路と連通する。この冷媒導入管９２は後述する中間冷却回路１５０に設けられたガスクーラ１５４を経てスリーブ１４４に至り、他端はスリーブ１４４内に挿入接続されて密閉容器１２内に連通する。
【００３０】
また、スリーブ１４２内には下シリンダ４０に冷媒ガスを導入するための冷媒導入管９４の一端が挿入接続され、この冷媒導入管９４の一端は下シリンダ４０の吸込通路６０と連通する。また、スリーブ１４３内には冷媒吐出管９６が挿入接続され、この冷媒吐出管９６の一端は吐出消音室６２と連通する。
【００３１】
次に図２において、上述したコンプレッサ１０は図２に示す冷媒回路の一部を構成する。即ち、コンプレッサ１０の冷媒吐出管９６はガスクーラ１５４の入口に接続される。そして、このガスクーラ１５４を出た配管は内部熱交換器１６０を通過する。この内部熱交換器１６０はガスクーラ１５４から出た高圧側の冷媒と蒸発器１５７から出た低圧側の冷媒とを熱交換させるためのものである。
【００３２】
内部熱交換器１６０を通過した配管は絞り手段としての膨張弁１５６に至る。そして、膨張弁１５６の出口は蒸発器１５７の入口に接続され、蒸発器１５７を出た配管は内部熱交換器１６０を経て冷媒導入管９４に接続される。
【００３３】
また、冷媒回路には本発明における高圧側と中間圧領域とを連通するバイパス回路１７０が設けられている。即ち、コンプレッサ１０からガスクーラ１５４に至る冷媒吐出管９６の中途部からはバイパス回路１７０が分岐している（図１では示さず）。そして、このバイパス回路１７０は冷媒回路における中間圧領域である中間冷却回路１５０（実施例ではガスクーラ１５４の手前側）に接続されている。このバイパス回路１７０には、高圧側からの冷媒を減圧するための減圧手段としてのキャピラリチューブ１７２と、バイパス回路１７０の流路を開閉するための弁装置としてのバイパス弁１７４が設けられている。このバイパス弁１７４は図示しない制御装置にて開閉が制御される。尚、前記中間圧領域は第１の回転圧縮要素３２で圧縮された冷媒が、第２の回転圧縮要素３４に吸い込まれるまでの経路の全てが相当するものであり、バイパス回路１７０は、実施例の位置に限らず、高圧側の冷媒ガスが通過する経路と中間圧の冷媒ガスが通過する経路とを連通するものであれば、接続箇所は特に限定されない。
【００３４】
以上の構成で次に本発明の冷媒サイクル装置の動作を説明する。尚、コンプレッサ１０の起動前には前記バイパス回路１７０のバイパス弁１７４は図示しない制御装置により閉じられているものとする。また、当該制御装置はコンプレッサ１０の電動要素１４を定速で運転するものであり、インバータなどの容量制御手段は用いない。即ち、制御装置によりターミナル２０及び図示されない配線を介してコンプレッサ１０の電動要素１４のステータコイル２８に通電されると、電動要素１４が起動してロータ２４が回転し始める。この電動要素１４の起動に同期して上記制御装置はバイパス回路１７０のバイパス弁１７４を開放する。
【００３５】
前記ロータ２４の回転により回転軸１６と一体に設けた上下偏心部４２、４４に嵌合された上下ローラ４６、４８が上下シリンダ３８、４０内を偏心回転する。これにより、冷媒導入管９４及び下部支持部材５６に形成された吸込通路６０を経由して図示しない吸込ポートからシリンダ４０の低圧室側に吸入された低圧（ＬＰ：通常運転状態で４ＭＰａ程）の冷媒ガスは、ローラ４８とベーン５２の動作により圧縮されて中間圧（ＭＰ：通常運転状態で８ＭＰａ程）となり下シリンダ４０の高圧室側より図示しない連通路を経て中間吐出管１２１から密閉容器１２内に吐出される。これによって、密閉容器１２内は中間圧（ＭＰ）となる。
【００３６】
そして、密閉容器１２内の中間圧の冷媒ガスは冷媒導入管９２に入り、スリーブ１４４から出て中間冷却回路１５０に流入する。そして、この中間冷却回路１５０がガスクーラ１５４を通過する過程で空冷方式により放熱する。このように、第１の回転圧縮要素３２で圧縮された中間圧の冷媒ガスを中間冷却回路１５０を通過させることで、ガスクーラ１５４にて効果的に冷却することができるので、密閉容器１２内の温度上昇を抑え、第２の回転圧縮要素３４における圧縮効率も向上させることができるようになる。
【００３７】
冷却された中間圧の冷媒ガスは上部支持部材５４に形成された図示しない吸込通路を経由して、図示しない吸込ポートから第２の回転圧縮要素３４の上シリンダ３８の低圧室側に吸入され、ローラ４６とベーン５０の動作により２段目の圧縮が行われて高温高圧（ＨＰ：通常運転状態で１２ＭＰａ程）の冷媒ガスとなり、高圧室側から図示しない吐出ポートを通り上部支持部材５４に形成された吐出消音室６２を経て冷媒吐出管９６より外部に吐出される。このとき、冷媒は適切な超臨界圧力まで圧縮されており、この冷媒吐出管９６から吐出された冷媒ガスはガスクーラ１５４に流入する。
【００３８】
ここで、コンプレッサ１０の電動要素１４はインバータなどを用いずに定速で運転されるため、その起動時には第２の回転圧縮要素３４の吐出側、即ち、高圧側の圧力は急激に上昇し、最悪の場合には冷媒回路の設計圧（耐圧限界）を超えてしまう場合もある。しかしながら、本発明では冷媒吐出管９６に吐出された冷媒ガスの一部は冷媒吐出管９６の途中部から分岐している前記バイパス回路１７０に流入し、そこでキャピラリチューブ１７２にて減圧された後、中間冷却回路１５０に逃げる。そして、密閉容器１２内からの中間圧の冷媒ガスと合流してガスクーラ１５４に流入し、前述した如くそこで放熱した後、第２の回転圧縮要素３４の上シリンダ３８の低圧室側に吸入されることになる。
【００３９】
このように、本発明では急激に上昇しようとする高圧側の冷媒ガスの一部を中間冷却回路１５０に逃がすので、図３に示すように高圧側の冷媒圧力が低下する。これにより、コンプレッサ１０の起動時（プルダウン時）に第２の回転圧縮要素３４で圧縮された冷媒ガスの圧力が異常に上昇して、冷媒回路内の冷媒配管等が劣化したり、最悪、破損すると云った不都合を回避することができるようになる。
【００４０】
また、冷媒ガスはバイパス回路１７０に設けられたキャピラリチューブ１７２にて減圧された後、中間冷却回路１５０に供給されるので、中間圧が必要以上に上昇し、第２の回転圧縮要素３４内の圧力と密閉容器１２内の圧力が逆転してしまう不都合も回避することができるようになる。更に、第２の回転圧縮要素３４で圧縮された冷媒ガスはバイパス回路１７０に設けられたキャピラリチューブ１７２にて減圧した後、中間圧の冷媒ガスと合流して、ガスクーラ１５４を通過するので、ガスクーラ１５４にて冷媒ガスを冷却することができる。このため、コンプレッサ１０の内部温度の上昇を防ぐことができるようになる。
【００４１】
尚、前記制御装置は、コンプレッサ１０を起動してから所定時間（１分乃至１０分）経過すると、バイパス弁１７４を閉じる。以後は第２の回転圧縮要素３４で圧縮され、冷媒吐出管９６に吐出された高圧の冷媒ガスは全て、ガスクーラ１５４に流入することになる。
【００４２】
他方、ガスクーラ１５４に流入した冷媒ガスは空冷方式により放熱した後、内部熱交換器１６０を通過する。冷媒はそこで低圧側の冷媒に熱を奪われて更に冷却される。これにより、冷媒の過冷却度が大きくなるという効果によって、蒸発器１５７における冷媒の冷却能力が向上する。
【００４３】
内部熱交換器１６０で冷却された高圧側の冷媒ガスは膨張弁１５６に至る。尚、膨張弁１５６の入口では冷媒ガスはまだ気体の状態である。冷媒は膨張弁１５６における圧力低下により、ガス／液体の二相混合体とされ、その状態で蒸発器１５７内に流入する。そこで冷媒は蒸発し、空気から吸熱することにより冷却作用を発揮する。
【００４４】
その後、冷媒は蒸発器１５７から流出して、内部熱交換器１６０を通過する。そこで前記高圧側の冷媒から熱を奪い、加熱作用を受ける。このように、蒸発器１５７で蒸発して低温となり、蒸発器１５７を出た冷媒は完全に気体の状態ではなく液体が混在した状態である。そこで、内部熱交換器１６０を通過させて高圧側の冷媒と熱交換させることで、冷媒は過熱度が取れて完全に気体となる。これにより、低圧側にアキュムレータを設けること無く、コンプレッサ１０に液冷媒が吸い込まれる液バックを確実に防止し、コンプレッサ１０が液圧縮にて損傷を受ける不都合を回避することができるようになる。
【００４５】
尚、内部熱交換器１６０で加熱された冷媒は、冷媒導入管９４からコンプレッサ１０の第１の回転圧縮要素３２内に吸い込まれるサイクルを繰り返す。このとき、起動時（プルダウン時）以外の通常運転状態（安定時）では、冷媒の圧力は図３に示すように冷媒回路内の冷媒配管などの前記設計圧（ＤＰ）を超えること無く、安定した圧力で運転される。
【００４６】
このように、冷媒回路の高圧側と中間冷却回路１５０とを連通するバイパス回路１７０と、当該バイパス回路１７０にキャピラリチューブ１７２及びバイパス弁１７４とを設けて、コンプレッサ１０の起動時等に、バイパス弁１７４によりバイパス回路１７０の流路を開放することで、高圧側の冷媒ガスを中間圧領域に逃がすことができるようになるので、起動時に高圧側の冷媒の圧力が異常上昇して、当該冷媒ガスにより配管を劣化させたり、最悪、破損すると云った不都合を回避することができるようになる。
【００４７】
これにより、冷媒サイクル装置の耐久性を確保することができ、信頼性の向上を図ることができるようになる。
【００４８】
更に、バイパス回路１７０に流入した冷媒ガスは当該バイパス回路１７０に設けられたキャピラリチューブ１７２にて減圧された後、中間冷却回路１５０に供給されるので、当該冷媒が中間冷却回路１５０に供給されることで、中間圧が上昇して第２の回転圧縮要素３４における高圧と中間圧の圧力逆転を起こすといった問題や高圧が更に上昇するといった不都合も回避することができるようになる。
【００４９】
尚、本実施例では図示しない制御装置によりバイパス弁１７４をコンプレッサ１０の起動時から開放し、その後所定時間経過した時点で閉じることとしたが、本発明はこれに限定されるものでなく、冷媒回路内の冷媒温度や冷媒圧力若しくはコンプレッサ１０の駆動電流が所定値に到達するまでバイパス回路１７０の流路を開放するものであっても良い。ここで、冷媒回路内の冷媒温度が所定値に到達するまでバイパス回路１７０の流路を開放するものとする場合、冷媒温度としては、例えば、蒸発器１５７における冷媒の蒸発温度を図示しない制御装置に接続された冷媒温度センサなどにより検出し、起動時からバイパス弁１７４を開いて、当該冷媒温度センサにて検出される蒸発器１５７における冷媒の蒸発温度が所定値に低下した時点で閉じる制御を行っても良い。
【００５０】
また、実施例ではコンプレッサ１０は内部中間圧型の多段（２段）圧縮式ロータリコンプレッサを用いて説明したが、本発明に使用可能なコンプレッサはこれに限定されるものではなく、３段以上の圧縮要素を備えた多段圧縮式のコンプレッサであっても本発明は有効である。尚、本実施例ではコンプレッサ１０を定速で運転するものとしたが、インバータによりコンプレッサの回転数制御するものに本発明を適応しても良い。この場合には、起動時の回転数制御をより容易に行うことができるようになるので、制御機能の簡素化を図ることができるようになる。
【００５１】
【発明の効果】
以上詳述する如く本発明の冷媒サイクル装置によれば、冷媒回路の高圧側と中間圧領域とを連通するバイパス回路と、このバイパス回路に設けられた減圧手段及び弁装置とを備え、コンプレッサの起動時に、請求項２乃至請求項５の如く弁装置によりバイパス回路の流路を開放するようにしたので、高圧側の冷媒をバイパス回路から中間圧領域に逃がすことが可能となる。
【００５２】
これにより、例えばコンプレッサが定速で運転される場合にも、起動時における高圧側が異常に上昇して、機器に損傷を引き起こすと云った不都合を未然に回避することができるようになる。
【００５３】
また、高圧側の冷媒はバイパス回路に設けられた減圧手段にて減圧した後、中間圧領域に流入するので、中間圧が上がり過ぎる不都合を回避することができるようになる。
【００５４】
総じて、耐久性の向上と円滑な運転を確保することができるようになり、冷媒サイクル装置の信頼性の向上を図ることができるようになる。
【００５５】
特に、請求項６の如き高圧側の圧力が極めて高くなる二酸化炭素を冷媒として用いる装置に好適であると共に、係る二酸化炭素を冷媒として使用すれば環境問題にも寄与することができるようになる。
【図面の簡単な説明】
【図１】本発明の冷媒サイクル装置に使用する実施例のロータリコンプレッサの縦断面図である。
【図２】本発明の冷媒サイクル装置の冷媒回路図である。
【図３】本発明の冷媒サイクル装置における冷媒圧力の推移を示す図である。
【図４】従来の冷媒サイクル装置の冷媒回路図である。
【図５】従来の冷媒サイクル装置における冷媒圧力の推移を示す図である。
【符号の説明】
１０ 多段圧縮式ロータリコンプレッサ
１２ 密閉容器
１４ 電動要素
３２ 第１の回転圧縮要素
３４ 第２の回転圧縮要素
９２、９４ 冷媒導入管
９６ 冷媒吐出管
１５０ 中間冷却回路
１５４ ガスクーラ
１５６ 膨張弁（絞り手段）
１５７ 蒸発器
１６０ 内部熱交換器
１７０ バイパス回路
１７２ キャピラリチューブ
１７４ バイパス弁[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a refrigerant cycle device in which a compressor, a gas cooler, a throttle device, and an evaporator are sequentially connected to form a refrigerant circuit.
[0002]
[Prior art]
In this type of conventional refrigerant cycle device, a rotary compressor (compressor), a gas cooler, a restrictor (expansion valve or the like), an evaporator, and the like are sequentially connected in a ring shape to form a refrigerant cycle (refrigerant circuit). Refrigerant gas is sucked into the low pressure chamber side of the cylinder from the suction port of the rotary compression element of the rotary compressor, and is compressed by the operation of the rollers and vanes to become high temperature and high pressure refrigerant gas. It is discharged to the gas cooler through the silencer. After the refrigerant gas radiates heat in this gas cooler, it is throttled by throttle means and supplied to the evaporator. Then, the refrigerant evaporates, and at that time, absorbs heat from the surroundings to exert a cooling effect.
[0003]
Here, in recent years, in order to deal with global environmental problems, even in this type of refrigerant cycle, carbon dioxide (CO 2 ), which is a natural refrigerant, is used as a refrigerant without using conventional chlorofluorocarbons, and the high pressure side is set to a supercritical pressure. Devices using an operating transcritical refrigerant cycle have been developed.
[0004]
In such a refrigerant cycle device, an accumulator is provided on a low pressure side between an outlet side of the evaporator and a suction side of the compressor in order to prevent the liquid refrigerant from returning into the compressor and performing liquid compression. The liquid refrigerant is stored in the compressor, and only the gas is sucked into the compressor. The throttle means is adjusted so that the liquid refrigerant in the accumulator does not return to the compressor (for example, see Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent Publication No. Hei 7-18602
However, providing an accumulator on the low pressure side of the refrigerant cycle requires a correspondingly large amount of refrigerant charge. Further, in order to prevent the liquid back, the opening of the throttle means must be reduced or the capacity of the accumulator must be increased, which causes a decrease in cooling capacity and an increase in installation space. Therefore, in order to eliminate the liquid compression in the compressor without providing such an accumulator, the applicant has conventionally attempted to develop a refrigerant cycle device shown in FIG.
[0007]
In FIG. 4, reference numeral 10 denotes an internal intermediate pressure type multi-stage (two-stage) compression type rotary compressor, and an electric element 14 as a driving element in a closed container 12 and a first shaft driven by a rotating shaft 16 of the electric element 14. And the second rotary compression element 34.
[0008]
The operation of the refrigerant cycle device in this case will be described. The low-pressure (LP) refrigerant sucked from the refrigerant introduction pipe 94 of the compressor 10 is compressed by the first rotary compression element 32 to an intermediate pressure (MP), and is discharged into the closed container 12. After that, the refrigerant flows out of the refrigerant introduction pipe 92 and flows into the intermediate cooling circuit 150A. The intermediate cooling circuit 150A is provided so as to pass through the gas cooler 154, where heat is radiated by an air cooling system. Here, the intermediate-pressure refrigerant loses heat in the gas cooler.
[0009]
Thereafter, the refrigerant is sucked into the second rotary compression element 34 and subjected to the second-stage compression to become a high-temperature and high-pressure (HP) refrigerant gas, which is discharged from the refrigerant discharge pipe 96 to the outside. At this time, the refrigerant has been compressed to an appropriate supercritical pressure.
[0010]
The refrigerant gas discharged from the refrigerant discharge pipe 96 flows into the gas cooler 154, where the refrigerant gas is radiated by an air cooling method, and then passes through the internal heat exchanger 160. The refrigerant is further cooled by being deprived of heat by the refrigerant on the low pressure side that has exited the evaporator 157. Thereafter, the pressure of the refrigerant is reduced by the expansion valve 156, and in the process, the refrigerant enters a gas / liquid mixed state. The refrigerant flowing out of the evaporator 157 passes through the internal heat exchanger 160, where it is heated by removing heat from the refrigerant on the high pressure side.
[0011]
Then, a cycle in which the refrigerant heated by the internal heat exchanger 160 is drawn into the first rotary compression element 32 of the rotary compressor 10 from the refrigerant introduction pipe 94 is repeated. In this way, the refrigerant flowing out of the evaporator 157 is heated by the high-pressure side refrigerant by the internal heat exchanger 160, so that the degree of superheat can be obtained. Therefore, the compressor can be provided without providing an accumulator or the like on the low-pressure side. It is possible to reliably prevent the liquid bag from sucking the liquid refrigerant into the compressor 10 and avoid the disadvantage that the compressor 10 is damaged by the liquid compression.
[0012]
[Problems to be solved by the invention]
On the other hand, in such a refrigerant cycle device using carbon dioxide, the pressure on the high pressure side usually rises to 12 MPa or more. In particular, when the compressor is operated at a constant speed, the pressure on the high pressure side further increases when the compressor is started (during pulldown), and exceeds the design pressure (DP) of the device as shown in FIG. May cause damage. Therefore, it is necessary to control the rotation speed (capacity control) of the compressor by the inverter or to adjust the opening degree of the expansion valve in addition to the control to suppress the pressure increase on the high pressure side to start the compressor.
[0013]
The present invention has been made in order to solve such a conventional technical problem, and it is possible to prevent the occurrence of inconvenience due to an abnormal increase in the high-pressure side pressure even when the compressor is operated at a constant speed. It is an object of the present invention to provide a refrigerant cycle device capable of performing the above.
[0014]
[Means for Solving the Problems]
That is, the refrigerant cycle device of the present invention includes a bypass circuit communicating the high pressure side of the refrigerant circuit and the intermediate pressure region, and a pressure reducing device and a valve device provided in the bypass circuit. Thus, the flow path of the bypass circuit is opened, so that the refrigerant on the high pressure side can escape from the bypass circuit to the intermediate pressure region.
[0015]
Thus, even when the compressor is operated at a constant speed, it is possible to avoid the disadvantage that the high-pressure side pressure abnormally rises at the time of startup, and to improve durability and ensure smooth operation. become. In addition, the refrigerant on the high pressure side is decompressed by the decompression means provided in the bypass circuit, and then flows into the intermediate pressure region, so that it is possible to avoid the disadvantage that the intermediate pressure is excessively increased.
[0016]
The invention of claim 2 is characterized in that, in addition to the above invention, the valve device opens the flow path of the bypass circuit for a predetermined time from the start of the compressor.
[0017]
According to a third aspect of the present invention, in addition to the first aspect, the valve device opens the flow path of the bypass circuit until the pressure of the refrigerant in the refrigerant circuit reaches a predetermined value from the start of the compressor. .
[0018]
According to a fourth aspect of the present invention, in addition to the first aspect, the valve device opens the flow path of the bypass circuit in which the drive current of the compressor reaches a predetermined value from the start of the compressor.
[0019]
According to a fifth aspect of the present invention, in addition to the first aspect, the valve device opens the flow path of the bypass circuit until the temperature of the refrigerant in the refrigerant circuit reaches a predetermined value from the start of the compressor. .
[0020]
In the invention of claim 6, in addition to the above inventions, carbon dioxide is used as a refrigerant, so that it can contribute to environmental problems.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of an internal intermediate pressure type multi-stage (two-stage) compression type rotary compressor 10 having first and second rotary compression elements 32 and 34 as an embodiment of a compressor used in the refrigerant cycle device of the present invention. FIG. 2 is a refrigerant circuit diagram of the refrigerant cycle device of the present invention.
[0022]
In each of the drawings, reference numeral 10 denotes an internal intermediate pressure type multistage compression type rotary compressor using carbon dioxide (CO 2 ) as a refrigerant. The compressor 10 includes a cylindrical hermetic container 12 made of a steel plate and an inner space of the hermetic container 12. An electric element 14 as a driving element disposed and housed on the upper side, and a first rotary compression element 32 (first stage) and a first rotary compression element 32 disposed below the electric element 14 and driven by the rotating shaft 16 of the electric element 14. The rotary compression mechanism 18 includes two rotary compression elements 34 (second stage).
[0023]
The closed container 12 has an oil reservoir at the bottom, a container body 12A that houses the electric element 14 and the rotary compression mechanism 18, and a substantially bowl-shaped end cap (lid) 12B that closes an upper opening of the container body 12A. A circular mounting hole 12D is formed in the center of the upper surface of the end cap 12B, and a terminal (wiring omitted) 20 for supplying electric power to the electric element 14 is mounted in the mounting hole 12D. Have been.
[0024]
The electric element 14 is a so-called magnetic pole concentrated winding type DC motor, and is inserted into the stator 22 annularly attached along the inner peripheral surface of the upper space of the closed casing 12 with a slight interval provided inside the stator 22. And an installed rotor 24. The rotor 24 is fixed to the rotating shaft 16 that extends vertically through the center. The stator 22 has a laminated body 26 in which donut-shaped electromagnetic steel sheets are laminated, and a stator coil 28 wound around teeth of the laminated body 26 by a direct winding (concentrated winding) method. The rotor 24 is formed of a laminated body 30 of electromagnetic steel sheets similarly to the stator 22, and is formed by inserting a permanent magnet MG into the laminated body 30.
[0025]
An intermediate partition plate 36 is held between the first rotary compression element 32 and the second rotary compression element 34. That is, the first rotary compression element 32 and the second rotary compression element 34 include an intermediate partition plate 36, an upper cylinder 38, a lower cylinder 40 disposed above and below the intermediate partition plate 36, The upper and lower rollers 46 and 48 are eccentrically rotated by upper and lower eccentric portions 42 and 44 provided on the rotating shaft 16 with a phase difference of 180 degrees in the inside 40, and the upper and lower cylinders abut on the upper and lower rollers 46 and 48. The vanes 50 and 52 partitioning the inside of the cylinders 38 and 40 into a low pressure chamber side and a high pressure chamber side, respectively, and the upper opening surface of the upper cylinder 38 and the lower opening surface of the lower cylinder 40 are closed so that the bearing of the rotating shaft 16 is closed. An upper supporting member 54 and a lower supporting member 56 are also used as supporting members.
[0026]
On the other hand, the upper support member 54 and the lower support member 56 have a suction passage 60 (the upper suction passage is not shown) communicating with the insides of the upper and lower cylinders 38 and 40 through a suction port (not shown), and a part thereof is recessed. The discharge muffling chambers 62 and 64 formed by closing the recess with the upper cover 66 and the lower cover 68 are provided.
[0027]
The discharge muffling chamber 64 and the inside of the closed container 12 are communicated with each other by a communication passage penetrating the upper and lower cylinders 38 and 40 and the intermediate partition plate 36, and an intermediate discharge pipe 121 is provided upright at the upper end of the communication passage. The intermediate pressure (MP) refrigerant gas compressed by the first rotary compression element 32 is discharged from the intermediate discharge pipe 121 into the closed container 12.
[0028]
As the refrigerant, the above-mentioned carbon dioxide (CO 2 ), which is a natural refrigerant in consideration of flammability and toxicity, is used for the earth environment, is used. Existing oils such as alkylbenzene oil, ether oil, ester oil, and PAG (polyalkyl glycol) are used.
[0029]
On the side surface of the container body 12A of the closed container 12, suction passages 60 (the upper side is not shown) of the upper support member 54 and the lower support member 56, the discharge muffling chamber 62, and the upper side of the upper cover 66 (at the lower end of the electric element 14). The sleeves 141, 142, 143, and 144 are respectively welded and fixed at positions corresponding to (substantially corresponding positions). One end of a refrigerant introduction pipe 92 for introducing refrigerant gas into the upper cylinder 38 is inserted into the sleeve 141, and one end of the refrigerant introduction pipe 92 communicates with a suction passage (not shown) of the upper cylinder 38. This refrigerant introduction pipe 92 reaches a sleeve 144 via a gas cooler 154 provided in an intermediate cooling circuit 150 described later, and the other end is inserted and connected into the sleeve 144 and communicates with the inside of the sealed container 12.
[0030]
One end of a refrigerant introduction pipe 94 for introducing refrigerant gas into the lower cylinder 40 is inserted and connected into the sleeve 142, and one end of the refrigerant introduction pipe 94 communicates with the suction passage 60 of the lower cylinder 40. Further, a refrigerant discharge pipe 96 is inserted and connected into the sleeve 143, and one end of the refrigerant discharge pipe 96 communicates with the discharge muffling chamber 62.
[0031]
Next, in FIG. 2, the above-described compressor 10 forms a part of the refrigerant circuit shown in FIG. That is, the refrigerant discharge pipe 96 of the compressor 10 is connected to the inlet of the gas cooler 154. Then, the pipe exiting the gas cooler 154 passes through the internal heat exchanger 160. The internal heat exchanger 160 is for exchanging heat between the high-pressure refrigerant discharged from the gas cooler 154 and the low-pressure refrigerant discharged from the evaporator 157.
[0032]
The pipe that has passed through the internal heat exchanger 160 reaches an expansion valve 156 as a throttle means. The outlet of the expansion valve 156 is connected to the inlet of the evaporator 157, and the pipe exiting the evaporator 157 is connected to the refrigerant introduction pipe 94 via the internal heat exchanger 160.
[0033]
Further, the refrigerant circuit is provided with a bypass circuit 170 for communicating the high pressure side and the intermediate pressure region in the present invention. That is, a bypass circuit 170 branches from a middle part of the refrigerant discharge pipe 96 extending from the compressor 10 to the gas cooler 154 (not shown in FIG. 1). The bypass circuit 170 is connected to the intermediate cooling circuit 150 (in this embodiment, the front side of the gas cooler 154) which is an intermediate pressure region in the refrigerant circuit. The bypass circuit 170 is provided with a capillary tube 172 as a pressure reducing means for reducing the pressure of the refrigerant from the high pressure side, and a bypass valve 174 as a valve device for opening and closing the flow path of the bypass circuit 170. The opening and closing of the bypass valve 174 is controlled by a control device (not shown). The intermediate pressure region corresponds to the entire path of the refrigerant compressed by the first rotary compression element 32 until it is sucked into the second rotary compression element 34. The connection location is not particularly limited as long as it connects the path through which the high-pressure refrigerant gas passes and the path through which the intermediate-pressure refrigerant gas passes.
[0034]
Next, the operation of the refrigerant cycle device of the present invention having the above configuration will be described. It is assumed that before the compressor 10 is started, the bypass valve 174 of the bypass circuit 170 is closed by a control device (not shown). The control device operates the electric element 14 of the compressor 10 at a constant speed, and does not use a capacity control means such as an inverter. That is, when power is supplied to the stator coil 28 of the electric element 14 of the compressor 10 via the terminal 20 and the wiring (not shown) by the control device, the electric element 14 starts and the rotor 24 starts rotating. The control device opens the bypass valve 174 of the bypass circuit 170 in synchronization with the activation of the electric element 14.
[0035]
The rotation of the rotor 24 causes the upper and lower rollers 46 and 48 fitted to the upper and lower eccentric portions 42 and 44 provided integrally with the rotating shaft 16 to eccentrically rotate inside the upper and lower cylinders 38 and 40. Thus, the low pressure (LP: about 4 MPa in the normal operation state) sucked into the low pressure chamber side of the cylinder 40 from the suction port (not shown) through the refrigerant introduction pipe 94 and the suction passage 60 formed in the lower support member 56. The refrigerant gas is compressed by the operation of the rollers 48 and the vanes 52 and becomes an intermediate pressure (MP: about 8 MPa in a normal operation state), from the high pressure chamber side of the lower cylinder 40 to the closed container 12 through a communication passage (not shown) from the intermediate discharge pipe 121. It is discharged into. Thereby, the inside of the sealed container 12 has an intermediate pressure (MP).
[0036]
Then, the intermediate-pressure refrigerant gas in the sealed container 12 enters the refrigerant introduction pipe 92, exits from the sleeve 144, and flows into the intermediate cooling circuit 150. The intermediate cooling circuit 150 radiates heat by an air cooling method in the process of passing through the gas cooler 154. Since the intermediate-pressure refrigerant gas compressed by the first rotary compression element 32 passes through the intermediate cooling circuit 150 in this manner, the refrigerant gas can be effectively cooled by the gas cooler 154. The temperature rise can be suppressed, and the compression efficiency of the second rotary compression element 34 can be improved.
[0037]
The cooled intermediate-pressure refrigerant gas is sucked into a low-pressure chamber side of the upper cylinder 38 of the second rotary compression element 34 from a suction port (not shown) via a suction passage (not shown) formed in the upper support member 54, The second stage of compression is performed by the operation of the roller 46 and the vane 50 to become a high-temperature and high-pressure (HP: about 12 MPa in a normal operation state) refrigerant gas. The refrigerant is discharged from the refrigerant discharge pipe 96 to the outside through the discharge muffling chamber 62. At this time, the refrigerant has been compressed to an appropriate supercritical pressure, and the refrigerant gas discharged from the refrigerant discharge pipe 96 flows into the gas cooler 154.
[0038]
Here, since the electric element 14 of the compressor 10 is operated at a constant speed without using an inverter or the like, the pressure on the discharge side of the second rotary compression element 34, that is, the pressure on the high pressure side sharply rises at the time of startup. In the worst case, it may exceed the design pressure (withstand pressure limit) of the refrigerant circuit. However, in the present invention, a part of the refrigerant gas discharged to the refrigerant discharge pipe 96 flows into the bypass circuit 170 branched from a middle part of the refrigerant discharge pipe 96, and after being decompressed by the capillary tube 172 there, Escape to the intermediate cooling circuit 150. Then, the refrigerant gas merges with the intermediate-pressure refrigerant gas from the inside of the sealed container 12, flows into the gas cooler 154, radiates heat there as described above, and is then sucked into the low-pressure chamber side of the upper cylinder 38 of the second rotary compression element 34. Will be.
[0039]
As described above, in the present invention, a part of the refrigerant gas on the high pressure side which is about to rise rapidly is released to the intermediate cooling circuit 150, so that the pressure of the refrigerant on the high pressure side decreases as shown in FIG. As a result, when the compressor 10 is started (during pull-down), the pressure of the refrigerant gas compressed by the second rotary compression element 34 abnormally increases, and the refrigerant pipes and the like in the refrigerant circuit are deteriorated, or at worst, damaged. Then, such inconvenience can be avoided.
[0040]
Further, the refrigerant gas is decompressed in the capillary tube 172 provided in the bypass circuit 170 and then supplied to the intermediate cooling circuit 150. Therefore, the intermediate pressure rises more than necessary, and the refrigerant gas in the second rotary compression element 34 The inconvenience that the pressure and the pressure in the closed vessel 12 are reversed can be avoided. Further, the refrigerant gas compressed by the second rotary compression element 34 is decompressed by the capillary tube 172 provided in the bypass circuit 170, then merges with the intermediate-pressure refrigerant gas, and passes through the gas cooler 154. At 154, the refrigerant gas can be cooled. Therefore, an increase in the internal temperature of the compressor 10 can be prevented.
[0041]
The control device closes the bypass valve 174 when a predetermined time (1 minute to 10 minutes) has elapsed since the start of the compressor 10. Thereafter, all of the high-pressure refrigerant gas compressed by the second rotary compression element 34 and discharged to the refrigerant discharge pipe 96 flows into the gas cooler 154.
[0042]
On the other hand, the refrigerant gas flowing into the gas cooler 154 radiates heat by an air cooling method, and then passes through the internal heat exchanger 160. The refrigerant then loses its heat to the low-pressure side refrigerant and is further cooled. Thereby, the cooling capacity of the refrigerant in the evaporator 157 is improved by the effect of increasing the degree of supercooling of the refrigerant.
[0043]
The high-pressure side refrigerant gas cooled by the internal heat exchanger 160 reaches the expansion valve 156. At the inlet of the expansion valve 156, the refrigerant gas is still in a gaseous state. The refrigerant is converted into a gas / liquid two-phase mixture by the pressure drop at the expansion valve 156, and flows into the evaporator 157 in that state. Then, the refrigerant evaporates and absorbs heat from the air to exert a cooling function.
[0044]
Thereafter, the refrigerant flows out of the evaporator 157 and passes through the internal heat exchanger 160. Then, heat is removed from the high-pressure side refrigerant, and the refrigerant is heated. In this way, the refrigerant evaporates to a low temperature in the evaporator 157, and the refrigerant exiting the evaporator 157 is not in a completely gaseous state but in a state in which liquid is mixed. Therefore, the refrigerant is passed through the internal heat exchanger 160 to exchange heat with the refrigerant on the high pressure side, so that the refrigerant has a degree of superheat and is completely gaseous. As a result, without providing an accumulator on the low pressure side, it is possible to reliably prevent the liquid back in which the liquid refrigerant is sucked into the compressor 10, and to avoid the disadvantage that the compressor 10 is damaged by the liquid compression.
[0045]
The cycle in which the refrigerant heated by the internal heat exchanger 160 is sucked from the refrigerant introduction pipe 94 into the first rotary compression element 32 of the compressor 10 repeats. At this time, in the normal operation state (stable state) other than the start-up (pull-down), the pressure of the refrigerant does not exceed the design pressure (DP) of the refrigerant pipe in the refrigerant circuit as shown in FIG. It is operated at the specified pressure.
[0046]
As described above, the bypass circuit 170 communicating the high pressure side of the refrigerant circuit and the intermediate cooling circuit 150, and the capillary tube 172 and the bypass valve 174 are provided in the bypass circuit 170, so that the bypass valve 170 is activated when the compressor 10 is started. By opening the flow path of the bypass circuit 170 by 174, the high-pressure side refrigerant gas can be released to the intermediate pressure region. Thus, it is possible to avoid the inconvenience of deteriorating the piping or, at worst, breaking it.
[0047]
Thereby, the durability of the refrigerant cycle device can be ensured, and the reliability can be improved.
[0048]
Further, the refrigerant gas flowing into the bypass circuit 170 is depressurized by the capillary tube 172 provided in the bypass circuit 170 and then supplied to the intermediate cooling circuit 150, so that the refrigerant is supplied to the intermediate cooling circuit 150. Thus, it is possible to avoid the problem that the intermediate pressure rises to cause the pressure reversal between the high pressure and the intermediate pressure in the second rotary compression element 34 and the disadvantage that the high pressure further rises.
[0049]
In the present embodiment, the bypass valve 174 is opened from the start of the compressor 10 by a control device (not shown) and then closed when a predetermined time has elapsed. However, the present invention is not limited to this. The flow path of the bypass circuit 170 may be opened until the refrigerant temperature or the refrigerant pressure in the circuit or the drive current of the compressor 10 reaches a predetermined value. Here, in a case where the flow path of the bypass circuit 170 is opened until the refrigerant temperature in the refrigerant circuit reaches a predetermined value, the refrigerant temperature may be, for example, a control device (not shown) that indicates the evaporation temperature of the refrigerant in the evaporator 157. Control by opening the bypass valve 174 from the time of startup and closing the bypass valve 174 when the evaporation temperature of the refrigerant in the evaporator 157 detected by the refrigerant temperature sensor drops to a predetermined value. You may go.
[0050]
Further, in the embodiment, the compressor 10 has been described using a multi-stage (two-stage) compression type rotary compressor of an internal intermediate pressure type. However, the compressor usable in the present invention is not limited to this, and three or more stages of compression can be used. The present invention is effective even with a multi-stage compression type compressor having components. In the present embodiment, the compressor 10 is operated at a constant speed. However, the present invention may be applied to a compressor in which the rotation speed of the compressor is controlled by an inverter. In this case, since the control of the number of revolutions at the time of starting can be performed more easily, the control function can be simplified.
[0051]
【The invention's effect】
As described in detail above, according to the refrigerant cycle device of the present invention, the refrigerant cycle device includes a bypass circuit communicating the high pressure side of the refrigerant circuit and the intermediate pressure region, and a pressure reducing device and a valve device provided in the bypass circuit. Since the flow path of the bypass circuit is opened by the valve device at the time of start-up, the refrigerant on the high pressure side can be released from the bypass circuit to the intermediate pressure region.
[0052]
Thus, for example, even when the compressor is operated at a constant speed, it is possible to obviate the problem that the high-pressure side at the time of startup abnormally rises and causes damage to equipment.
[0053]
Further, the refrigerant on the high pressure side is decompressed by the decompression means provided in the bypass circuit, and then flows into the intermediate pressure region, so that it is possible to avoid a disadvantage that the intermediate pressure is excessively increased.
[0054]
In general, it is possible to improve durability and ensure smooth operation, and to improve the reliability of the refrigerant cycle device.
[0055]
In particular, the present invention is suitable for an apparatus using carbon dioxide whose pressure on the high pressure side is extremely high as a refrigerant as described in claim 6, and using such carbon dioxide as a refrigerant can contribute to environmental problems.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a rotary compressor of an embodiment used for a refrigerant cycle device of the present invention.
FIG. 2 is a refrigerant circuit diagram of the refrigerant cycle device of the present invention.
FIG. 3 is a diagram showing a change in refrigerant pressure in the refrigerant cycle device of the present invention.
FIG. 4 is a refrigerant circuit diagram of a conventional refrigerant cycle device.
FIG. 5 is a diagram showing a change in refrigerant pressure in a conventional refrigerant cycle device.
[Explanation of symbols]
Reference Signs List 10 multi-stage compression rotary compressor 12 closed container 14 electric element 32 first rotary compression element 34 second rotary compression element 92, 94 refrigerant introduction pipe 96 refrigerant discharge pipe 150 intermediate cooling circuit 154 gas cooler 156 expansion valve (throttle means)
157 Evaporator 160 Internal heat exchanger 170 Bypass circuit 172 Capillary tube 174 Bypass valve

Claims (6)

コンプレッサ、ガスクーラ、絞り手段及び蒸発器を順次接続して冷媒回路が構成されると共に、前記コンプレッサは、駆動要素にて駆動される第１及び第２の圧縮要素を備え、前記冷媒回路の低圧側から前記第１の圧縮要素に冷媒を吸い込んで圧縮し、当該第１の圧縮要素から吐出された中間圧の冷媒を前記第２の圧縮要素に吸い込み、圧縮して前記冷媒回路の高圧側に吐出する冷媒サイクル装置において、
前記冷媒回路の高圧側と中間圧領域とを連通するバイパス回路と、
該バイパス回路に設けられた減圧手段及び弁装置とを備え、
前記コンプレッサの起動時に、前記弁装置により前記バイパス回路の流路を開放することを特徴とする冷媒サイクル装置。A compressor, a gas cooler, a throttle device, and an evaporator are sequentially connected to form a refrigerant circuit, and the compressor includes first and second compression elements driven by driving elements, and a low-pressure side of the refrigerant circuit. The refrigerant is sucked into the first compression element and compressed, and the intermediate-pressure refrigerant discharged from the first compression element is sucked into the second compression element, compressed and discharged to the high-pressure side of the refrigerant circuit. Refrigerant cycle device,
A bypass circuit communicating the high pressure side of the refrigerant circuit and the intermediate pressure region,
Comprising a pressure reducing means and a valve device provided in the bypass circuit,
A refrigerant cycle device wherein the flow path of the bypass circuit is opened by the valve device when the compressor is started. 前記弁装置により、前記コンプレッサの起動から所定時間前記バイパス回路の流路を開放することを特徴とする請求項１の冷媒サイクル装置。2. The refrigerant cycle device according to claim 1, wherein the valve device opens the flow path of the bypass circuit for a predetermined time from the start of the compressor. 前記弁装置により、前記コンプレッサの起動から前記冷媒回路内の冷媒の圧力が所定値に到達するまで前記バイパス回路の流路を開放することを特徴とする請求項１の冷媒サイクル装置。2. The refrigerant cycle device according to claim 1, wherein the valve device opens the flow path of the bypass circuit until the pressure of the refrigerant in the refrigerant circuit reaches a predetermined value from the activation of the compressor. 前記弁装置により、前記コンプレッサの起動から当該コンプレッサの駆動電流が所定値に到達する前記バイパス回路の流路を開放することを特徴とする請求項１の冷媒サイクル装置。2. The refrigerant cycle device according to claim 1, wherein the valve device opens a flow path of the bypass circuit at which a drive current of the compressor reaches a predetermined value from the start of the compressor. 3. 前記弁装置により、前記コンプレッサの起動から前記冷媒回路内の冷媒の温度が所定値に到達するまで前記バイパス回路の流路を開放することを特徴とする請求項１の冷媒サイクル装置。2. The refrigerant cycle device according to claim 1, wherein the valve device opens the flow path of the bypass circuit until the temperature of the refrigerant in the refrigerant circuit reaches a predetermined value from the start of the compressor. 前記冷媒として二酸化炭素を使用することを特徴とする請求項１、請求項２、請求項３、請求項４又は請求項５の冷媒サイクル装置。The refrigerant cycle device according to claim 1, wherein carbon dioxide is used as the refrigerant.
JP2003040170A 2003-02-18 2003-02-18 Refrigerant cycle device Pending JP2004251492A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007083560A1 (en) * 2006-01-19 2007-07-26 Daikin Industries, Ltd. Refrigeration system
JP2008215773A (en) * 2007-03-07 2008-09-18 Mitsubishi Electric Corp Air conditioner
JP2010210205A (en) * 2009-03-12 2010-09-24 Daikin Ind Ltd Refrigerating device and method for operating the same
JP2011007350A (en) * 2009-06-23 2011-01-13 Sanyo Electric Co Ltd Refrigerating device
CN103940051A (en) * 2014-05-13 2014-07-23 珠海格力电器股份有限公司 Control method and control system for mode conversion of air conditioner

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007083560A1 (en) * 2006-01-19 2007-07-26 Daikin Industries, Ltd. Refrigeration system
JP2007192470A (en) * 2006-01-19 2007-08-02 Daikin Ind Ltd Refrigerating device
AU2007206539B2 (en) * 2006-01-19 2010-06-03 Daikin Industries, Ltd. Refrigerating apparatus
KR101003228B1 (en) * 2006-01-19 2010-12-21 다이킨 고교 가부시키가이샤 Refrigeration system
CN101371083B (en) * 2006-01-19 2011-07-20 大金工业株式会社 Refrigeration apparatus
US8109111B2 (en) 2006-01-19 2012-02-07 Daikin Industries, Ltd. Refrigerating apparatus having an intermediate-pressure refrigerant gas-liquid separator for performing refrigeration cycle
JP2008215773A (en) * 2007-03-07 2008-09-18 Mitsubishi Electric Corp Air conditioner
JP2010210205A (en) * 2009-03-12 2010-09-24 Daikin Ind Ltd Refrigerating device and method for operating the same
JP2011007350A (en) * 2009-06-23 2011-01-13 Sanyo Electric Co Ltd Refrigerating device
CN103940051A (en) * 2014-05-13 2014-07-23 珠海格力电器股份有限公司 Control method and control system for mode conversion of air conditioner

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