JP4278402B2 - Refrigerant cycle equipment - Google Patents

Refrigerant cycle equipment Download PDF

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Publication number
JP4278402B2
JP4278402B2 JP2003041197A JP2003041197A JP4278402B2 JP 4278402 B2 JP4278402 B2 JP 4278402B2 JP 2003041197 A JP2003041197 A JP 2003041197A JP 2003041197 A JP2003041197 A JP 2003041197A JP 4278402 B2 JP4278402 B2 JP 4278402B2
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refrigerant
compressor
pressure
circuit
compression element
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JP2004251513A (en
Inventor
兼三 松本
茂弥 石垣
晴久 山崎
正司 山中
一昭 藤原
恒久 湯本
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Sanyo Electric Co Ltd
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Sanyo Electric Co Ltd
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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

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、冷媒が空冷方式により放熱する。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した後、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、第１の圧縮要素から吐出され、第２の圧縮要素に吸い込まれる冷媒を放熱させるための中間冷却回路と、この中間冷却回路と低圧側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、中間冷却回路は、ガスクーラを通過するよう設けられると共に、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、第１の圧縮要素で圧縮され中間冷却回路に流入した中間圧の冷媒をバイパス回路から低圧側に逃がすことが可能となる。
【００１５】
中間圧の冷媒ガスが低圧側に流入することで、中間圧が低下し、これに伴い、高圧側の圧力も低下するので、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圧力が異常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、中間圧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、低圧側に流入するので、低圧側の圧力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】
特に、中間冷却回路はガスクーラを通過するよう設けられているので、第１の圧縮要素で圧縮された中間圧の冷媒はガスクーラにて冷却した後、低圧側の冷媒と合流するので、コンプレッサの内部温度の上昇を防ぐことができるようになる。
【００１７】
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。
【００１８】
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。
【００１９】
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。
【００２１】
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。
【００２２】
【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の回転圧縮要素（第１の圧縮要素）３２及び第２の回転圧縮要素（第２の圧縮要素）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。
【００２３】
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。
【００２４】
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。
【００２５】
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。
【００２６】
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。
【００２７】
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。
【００２８】
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。
【００２９】
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。
【００３０】
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。
【００３１】
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。
【００３２】
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を出た冷媒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。
【００３３】
内部熱交換器１６０を通過した冷媒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を出た冷媒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。
【００３４】
また、冷媒回路には本発明における中間圧領域と低圧側とを連通するバイパス回路１７０が設けられている。即ち、中間圧領域である中間冷却回路１５０のガスクーラ１５４からコンプレッサ１０に至る冷媒導入管９２の途中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、バイパス回路１７０は冷媒回路における低圧側である冷媒導入管９４に接続されている。このバイパス回路１７０には、中間圧領域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、中間圧の冷媒ガスが通過する経路と低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。
【００３５】
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。
【００３６】
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。
【００３７】
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に流入した冷媒ガスがガスクーラ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。
【００３８】
ガスクーラ１５４にて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る。
【００３９】
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、本発明では中間冷却回路１５０においてガスクーラ１５４で冷却された冷媒ガスの一部はガスクーラ１５４からコンプレッサ１０に至る冷媒導入管９２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、冷媒導入管９４に逃げる。そして、蒸発器１５７を経て内部熱交換器１６０からの低圧側の冷媒ガスと合流して第１の回転圧縮要素３２の下シリンダ４０の低圧室側に吸入されることになる。これにより、中間圧領域の冷媒ガスの一部を冷媒導入管９４に逃がすことができるので、中間圧領域の冷媒圧力が低下する。
【００４０】
即ち、第２の回転圧縮要素３４に吸い込まれる冷媒ガスの圧力が低下することで、第２の回転圧縮要素３４で圧縮される冷媒ガスの圧力上昇も抑えることができる。このように、本発明では中間圧の冷媒ガスの一部を冷媒導入管９４に逃がすので、図３に示すように中間圧領域の冷媒圧力が低下し、その結果、高圧側の冷媒の圧力上昇が抑えられる。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。
【００４１】
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、冷媒導入管９４に供給されるので、低圧が必要以上に上昇し、中間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。更に、第１の回転圧縮要素３２で圧縮された冷媒ガスはガスクーラ１５４を通過する過程で放熱し、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、低圧の冷媒ガスと合流する。このように、ガスクーラ１５４にて中間圧領域の冷媒ガスを冷却した後に、低圧側の冷媒と合流させることで、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。
【００４２】
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１の回転圧縮要素３２で圧縮され、冷媒導入管９２に入り、スリーブ１４４を出て中間冷却回路１５０に流入し、ガスクーラ１５４にて放熱した冷媒ガスは全て、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ることになる。
【００４３】
他方、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た冷媒ガスは、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。
【００４４】
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。
【００４５】
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。
【００４６】
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。
【００４７】
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。
【００４８】
このように、冷媒回路の中間圧領域と低圧側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、中間圧領域の冷媒ガスを低圧側に逃がすことができるようになる。これにより、中間圧領域の冷媒圧力が低下し、第２の回転圧縮要素３４で圧縮される冷媒ガスの圧力上昇も抑えることができるようになる。このため、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冷媒配管が劣化したり、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。
【００４９】
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。
【００５０】
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、低圧側に流入するので、当該冷媒が低圧側に流入することで、低圧が上昇して、中間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。
【００５１】
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、例えば、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の起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。また、上記冷媒回路内の冷媒温度によりバイパス回路への冷媒流通を制御する場合、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。
【００５２】
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。
【００５３】
【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、第１の圧縮要素から吐出され、第２の圧縮要素に吸い込まれる冷媒を放熱させるための中間冷却回路と、この中間冷却回路と低圧側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、中間冷却回路は、ガスクーラを通過するよう設けられると共に、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、第１の圧縮要素で圧縮され中間冷却回路に流入した中間圧の冷媒をバイパス回路から低圧側に逃がすことが可能となる。
【００５４】
中間圧の冷媒ガスが低圧側に流入することで、中間圧が低下し、これに伴い、高圧側の圧力も低下するので、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圧力が異常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、中間圧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、低圧側に流入するので、低圧側の圧力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。
【００５５】
また、中間圧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、低圧側に流入するので、低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。
【００５６】
特に、中間冷却回路はガスクーラを通過するよう設けられているので、第１の圧縮要素で圧縮された中間圧の冷媒はガスクーラにて冷却した後、低圧側の冷媒と合流するので、コンプレッサの内部温度の上昇を防ぐことができるようになる。
【００５７】
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。
【００５８】
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]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigerant cycle apparatus in which a refrigerant circuit is configured by sequentially connecting a compressor, a gas cooler, a throttle means, and an evaporator.
[0002]
[Prior art]
In this type of conventional refrigerant cycle apparatus, a rotary compressor (compressor), a gas cooler, a throttle means (expansion valve, etc.), an evaporator, and the like are sequentially connected in an annular manner to form a refrigerant cycle (refrigerant circuit). Then, the 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 roller and the vane to become a high temperature and high pressure refrigerant gas. It is discharged to the gas cooler through the silencer chamber. The refrigerant gas radiates heat in the gas cooler, and is then squeezed by the squeezing means and supplied to the evaporator. Therefore, the refrigerant evaporates, and at that time, the cooling effect is exhibited by absorbing heat from the surroundings.
[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 chlorofluorocarbon, and the high pressure side is used as a supercritical pressure. Devices using transcritical refrigerant cycles to operate have been developed.
[0004]
In such a refrigerant cycle device, an accumulator is disposed on the low pressure side between the outlet side of the evaporator and the suction side of the compressor in order to prevent the liquid refrigerant from returning into the compressor and compressing the liquid. The liquid refrigerant was stored in the tank and only the gas was sucked into the compressor. And the throttle means was adjusted so that the liquid refrigerant in an accumulator may not return to a compressor (for example, refer to patent documents 1).
[0005]
[Patent Document 1]
Japanese Examined Patent Publication No. 7-18602 [0006]
However, providing an accumulator on the low-pressure side of the refrigerant cycle requires a larger amount of refrigerant filling. Further, in order to prevent liquid back, the opening of the throttle means must be reduced or the capacity of the accumulator must be increased, leading to a reduction 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 tried to develop the refrigerant cycle apparatus shown in FIG.
[0007]
In FIG. 4, reference numeral 10 denotes an internal intermediate pressure type multi-stage (two-stage) compression rotary compressor, and the first rotary compression element driven by the electric element 14 in the hermetic container 12 and the rotating shaft 16 of the electric element 14. 32 and a 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 sealed container 12. Thereafter, the refrigerant leaves 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 the refrigerant dissipates heat by an air cooling method. Here, the intermediate pressure refrigerant is deprived of heat by the gas cooler.
[0009]
Thereafter, the second rotary compression element 34 is sucked into the second stage of compression and becomes 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 is compressed to an appropriate supercritical pressure.
[0010]
The refrigerant gas discharged from the refrigerant discharge pipe 96 flows into the gas cooler 154, where it dissipates heat by an air cooling method, and then passes through the internal heat exchanger 160. The refrigerant is further cooled by taking heat away from the low-pressure side refrigerant that has left the evaporator 157. Thereafter, the refrigerant is depressurized by the expansion valve 156, and in this process, a gas / liquid mixed state is obtained. The refrigerant coming out of the evaporator 157 passes through the internal heat exchanger 160, where it is heated by taking heat from the high-pressure side refrigerant.
[0011]
The refrigerant heated by the internal heat exchanger 160 repeats a cycle of being sucked into the first rotary compression element 32 of the rotary compressor 10 from the refrigerant introduction pipe 94. In this way, the refrigerant that has come out of the evaporator 157 is heated by the internal heat exchanger 160 with the high-pressure side refrigerant, so that the degree of superheat can be obtained, and the compressor can be provided without providing an accumulator or the like on the low-pressure side. The liquid back into which the liquid refrigerant is sucked into 10 can be prevented, and the disadvantage that the compressor 10 is damaged by the liquid compression can be avoided.
[0012]
[Problems to be solved by the invention]
On the other hand, in the refrigerant cycle apparatus using such carbon dioxide, the pressure on the high pressure side rises to 12 MPa or more even in normal cases. 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 (when pulling down), and exceeds the design pressure (DP) of the device as shown in FIG. May cause damage. Therefore, it is necessary to start the compressor while controlling the rotation speed (capacity control) of the compressor by the inverter or by adjusting the opening of the expansion valve in addition to suppressing the pressure increase on the high pressure side.
[0013]
The present invention has been made to solve the conventional technical problem, and it is possible to avoid 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 that can be used.
[0014]
[Means for Solving the Problems]
That is, in the refrigerant cycle device of the present invention, an intermediate cooling circuit for dissipating the refrigerant discharged from the first compression element and sucked into the second compression element, and a bypass communicating the intermediate cooling circuit and the low pressure side comprising a circuit, a decompression means and a valve device provided in the bypass circuit, intermediate cooling circuit, with provided so as to pass through the gas cooler, at the start of the compressor, so opening the flow path of the bypass circuit by the valve device The intermediate pressure refrigerant compressed by the first compression element and flowing into the intermediate cooling circuit can be released from the bypass circuit to the low pressure side.
[0015]
Since the intermediate pressure of the refrigerant gas flows into the low pressure side, the intermediate pressure decreases, and the pressure on the high pressure side also decreases.Therefore, even when the compressor is operated at a constant speed, It is possible to avoid the inconvenience that the pressure increases abnormally, and to improve the durability and ensure smooth operation. Further, since the intermediate pressure refrigerant is decompressed by the decompression means provided in the bypass circuit and then flows into the low pressure side, it is possible to avoid the disadvantage that the pressure on the low pressure side is excessively increased.
[0016]
In particular, since the intermediate cooling circuit is provided so as to pass through the gas cooler, the intermediate-pressure refrigerant compressed by the first compression element is cooled by the gas cooler and then merged with the low-pressure side refrigerant. It becomes possible to prevent the temperature from rising.
[0017]
The invention of claim 2 is characterized in that, in addition to the above invention, the flow path of the bypass circuit is opened for a predetermined time from the start of the compressor by a valve device.
[0018]
The invention of claim 3 is characterized in that, in addition to the invention of claim 1, the valve device opens the flow path of the bypass circuit from the start of the compressor until the pressure of the refrigerant in the refrigerant circuit reaches a predetermined value. .
[0019]
The invention of claim 4 is characterized in that, in addition to the invention of claim 1, the valve device opens the flow path of the bypass circuit from the start of the compressor until the drive current of the compressor reaches a predetermined value.
[0020]
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 from the start of the compressor until the temperature of the refrigerant in the refrigerant circuit reaches a predetermined value. .
[0021]
In the invention of claim 6, in addition to the above-mentioned inventions, carbon dioxide is used as a refrigerant, so that it can contribute to environmental problems.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 includes a first rotary compression element (first compression element) 32 and a second rotary compression element (second compression element) 34 as an example of a compressor used in the refrigerant cycle apparatus of the present invention. FIG. 2 is a longitudinal sectional view of an internal intermediate pressure type multi-stage (two-stage) compression rotary compressor 10, and FIG. 2 is a refrigerant circuit diagram of the refrigerant cycle apparatus of the present invention.
[0023]
In each figure, reference numeral 10 denotes an internal intermediate pressure type multistage compression rotary compressor that uses carbon dioxide (CO 2 ) as a refrigerant. The compressor 10 includes a cylindrical sealed container 12 made of a steel plate, and an internal space of the sealed container 12. The electric element 14 as a driving element arranged and housed on the upper side, the first rotary compression element 32 (first stage) arranged on the lower side of the electric element 14 and driven by the rotating shaft 16 of the electric element 14 and the first The rotary compression mechanism section 18 is composed of two rotary compression elements 34 (second stage).
[0024]
The sealed 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 generally bowl-shaped end cap (lid body) 12B that closes the 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 is omitted) 20 for supplying power to the electric element 14 is mounted in the mounting hole 12D. It has been.
[0025]
The electric element 14 is a so-called magnetic pole concentrated winding type DC motor, and is inserted into the stator 22 in an annular shape along the inner peripheral surface of the upper space of the hermetic container 12, and is inserted inside the stator 22 with a slight gap therebetween. The rotor 24 is installed. The rotor 24 is fixed to a rotating shaft 16 that passes through the center and extends in the vertical direction. The stator 22 has a laminated body 26 in which donut-shaped electromagnetic steel plates are laminated, and a stator coil 28 wound around the teeth of the laminated body 26 by a direct winding (concentrated winding) method. Similarly to the stator 22, the rotor 24 is formed of a laminated body 30 of electromagnetic steel plates, and is formed by inserting a permanent magnet MG into the laminated body 30.
[0026]
An intermediate partition plate 36 is sandwiched 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 and a lower cylinder 40 disposed above and below the intermediate partition plate 36, and the upper and lower cylinders 38, The upper and lower rollers 46 and 48 are rotated eccentrically by upper and lower eccentric portions 42 and 44 provided on the rotary shaft 16 with a phase difference of 180 degrees, and the upper and lower cylinders are in contact with the upper and lower rollers 46 and 48. 38 and 40 are divided 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 to support the bearing of the rotary shaft 16. The upper support member 54 and the lower support member 56 are also used as the supporting members.
[0027]
On the other hand, the upper support member 54 and the lower support member 56 are respectively provided with a suction passage 60 (the upper suction passage is not shown) that communicates with the inside of the upper and lower cylinders 38 and 40 through a suction port (not shown), and a part thereof is recessed. Discharge silencing chambers 62 and 64 formed by closing the recessed portion with an upper cover 66 and a lower cover 68 are provided.
[0028]
The discharge silencer chamber 64 and the inside of the sealed container 12 are communicated with each other through a communication passage that penetrates 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 sealed container 12.
[0029]
And, as the refrigerant, the above-mentioned carbon dioxide (CO 2 ), which is a natural refrigerant in consideration of flammability and toxicity, is used as the refrigerant, and the oil as the lubricating oil is, for example, mineral oil (mineral oil), Existing oils such as alkylbenzene oil, ether oil, ester oil, and PAG (polyalkyl glycol) are used.
[0030]
On the side surface of the container main body 12A of the sealed container 12, the suction passage 60 (upper side is not shown) of the upper support member 54 and the lower support member 56, the discharge silencer chamber 62, the upper side of the upper cover 66 (on the lower end of the electric element 14). Sleeves 141, 142, 143, and 144 are 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 and connected 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. The refrigerant introduction pipe 92 reaches a sleeve 144 through 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 to communicate with the sealed container 12.
[0031]
In addition, one end of a refrigerant introduction pipe 94 for introducing refrigerant gas into the lower cylinder 40 is inserted and connected in the sleeve 142, and one end of the refrigerant introduction pipe 94 communicates with the suction passage 60 of the lower cylinder 40. In addition, 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 silencer chamber 62.
[0032]
Next, in FIG. 2, the compressor 10 mentioned above comprises a part of 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 refrigerant 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 coming out of the gas cooler 154 and the low-pressure refrigerant coming out of the evaporator 157.
[0033]
The refrigerant 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 refrigerant pipe exiting the evaporator 157 is connected to the refrigerant introduction pipe 94 via the internal heat exchanger 160.
[0034]
The refrigerant circuit is provided with a bypass circuit 170 that communicates the intermediate pressure region and the low pressure side in the present invention. That is, the bypass circuit 170 branches off from the middle part of the refrigerant introduction pipe 92 from the gas cooler 154 of the intermediate cooling circuit 150 which is an intermediate pressure region to the compressor 10 (not shown in FIG. 1). The bypass circuit 170 is connected to a refrigerant introduction pipe 94 on the low pressure side of the refrigerant circuit. The bypass circuit 170 is provided with a capillary tube 172 serving as a decompressing means for decompressing the refrigerant from the intermediate pressure region, and a bypass valve 174 serving as a valve device for opening and closing the flow path of the bypass circuit 170. . The bypass valve 174 is controlled to be opened and closed by a control device (not shown). The intermediate pressure region corresponds to the entire path until the refrigerant compressed by the first rotary compression element 32 is sucked into the second rotary compression element 34, and the bypass circuit 170 is an embodiment of the present invention. The connection location is not particularly limited as long as the path through which the intermediate-pressure refrigerant gas passes and the path through which the low-pressure refrigerant gas pass are communicated.
[0035]
Next, the operation of the refrigerant cycle apparatus of the present invention will be described with the above configuration. It is assumed that the bypass valve 174 of the bypass circuit 170 is closed by a control device (not shown) before the compressor 10 is started. The control device operates the electric element 14 of the compressor 10 at a constant speed, and does not use capacity control means such as an inverter. That is, when the control device energizes the stator coil 28 of the electric element 14 of the compressor 10 via the terminal 20 and a wiring (not shown), the electric element 14 is activated and the rotor 24 starts to rotate. In synchronization with the activation of the electric element 14, the control device opens the bypass valve 174 of the bypass circuit 170.
[0036]
As the rotor 24 rotates, the upper and lower rollers 46 and 48 fitted to the upper and lower eccentric portions 42 and 44 provided integrally with the rotary shaft 16 eccentrically rotate in the upper and lower cylinders 38 and 40. Thereby, the low pressure (LP: about 4 MPa in the normal operation state) sucked from the suction port (not shown) to the low pressure chamber side of the cylinder 40 via the suction passage 60 formed in the refrigerant introduction pipe 94 and the lower support member 56. The refrigerant gas is compressed by the operation of the roller 48 and the vane 52 to become an intermediate pressure (MP: about 8 MPa in a normal operation state) from the high pressure chamber side of the lower cylinder 40 through a communication path (not shown) from the intermediate discharge pipe 121 to the sealed container 12. It is discharged inside. Thereby, the inside of the sealed container 12 becomes an intermediate pressure (MP).
[0037]
The intermediate-pressure refrigerant gas in the sealed container 12 enters the refrigerant introduction pipe 92, exits the sleeve 144, and flows into the intermediate cooling circuit 150. The refrigerant gas that has flowed into the intermediate cooling circuit 150 dissipates heat by an air cooling method in the process of passing through the gas cooler 154. In this way, the refrigerant gas having the intermediate pressure compressed by the first rotary compression element 32 can be effectively cooled by the gas cooler 154 by passing through the intermediate cooling circuit 150. The temperature rise can be suppressed, and the compression efficiency in the second rotary compression element 34 can be improved.
[0038]
The intermediate-pressure refrigerant gas cooled by the gas cooler 154 passes through a suction passage (not shown) formed in the upper support member 54 and is connected to a low pressure chamber side of the upper cylinder 38 of the second rotary compression element 34 from a suction port (not shown). Inhaled.
[0039]
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 suddenly rises at the time of activation. In the worst case, the design pressure (pressure limit) of the refrigerant circuit may be exceeded. However, in the present invention, a part of the refrigerant gas cooled by the gas cooler 154 in the intermediate cooling circuit 150 flows into the bypass circuit 170 branched from the middle portion of the refrigerant introduction pipe 92 extending from the gas cooler 154 to the compressor 10. After being depressurized by the capillary tube 172, it escapes to the refrigerant introduction tube 94. Then, it passes through the evaporator 157 and merges with the low-pressure side refrigerant gas from the internal heat exchanger 160 and is sucked into the low-pressure chamber side of the lower cylinder 40 of the first rotary compression element 32. As a result, a part of the refrigerant gas in the intermediate pressure region can escape to the refrigerant introduction pipe 94, so that the refrigerant pressure in the intermediate pressure region decreases.
[0040]
That is, since the pressure of the refrigerant gas sucked into the second rotary compression element 34 is reduced, an increase in the pressure of the refrigerant gas compressed by the second rotary compression element 34 can also be suppressed. In this way, in the present invention, a part of the refrigerant gas at the intermediate pressure is released to the refrigerant introduction pipe 94, so that the refrigerant pressure in the intermediate pressure region is lowered as shown in FIG. 3, and as a result, the pressure of the refrigerant on the high pressure side is increased. Is suppressed. As a result, the pressure of the refrigerant gas compressed by the second rotary compression element 34 is abnormally increased when the compressor 10 is started (at the time of pull-down), and the refrigerant piping in the refrigerant circuit is deteriorated or worst-cased or damaged. This makes it possible to avoid such inconveniences.
[0041]
Further, since the refrigerant gas is depressurized by the capillary tube 172 provided in the bypass circuit 170 and then supplied to the refrigerant introduction pipe 94, the disadvantage that the low pressure rises more than necessary and the intermediate pressure further rises is avoided. Will be able to. Further, the refrigerant gas compressed by the first rotary compression element 32 dissipates heat in the process of passing through the gas cooler 154, and is decompressed by the capillary tube 172 provided in the bypass circuit 170, and then merges with the low-pressure refrigerant gas. In this way, after the refrigerant gas in the intermediate pressure region is cooled by the gas cooler 154, the refrigerant is combined with the refrigerant on the low pressure side, thereby preventing an increase in the internal temperature of the compressor 10.
[0042]
The control device closes the bypass valve 174 when a predetermined time (1 to 10 minutes) elapses after the compressor 10 is started. Thereafter, the refrigerant is compressed by the first rotary compression element 32, enters the refrigerant introduction pipe 92, exits the sleeve 144, flows into the intermediate cooling circuit 150, and all the refrigerant gas radiated by the gas cooler 154 is formed in the upper support member 54. The air is sucked into the low pressure chamber side of the upper cylinder 38 of the second rotary compression element 34 from the suction port (not shown) via the suction passage (not shown).
[0043]
On the other hand, the refrigerant gas sucked into the low-pressure chamber side of the upper cylinder 38 of the second rotary compression element 34 is compressed in the second stage by the operation of the roller 46 and the vane 50, so that the high-temperature and high-pressure (HP: normal operation state) And is discharged from the refrigerant discharge pipe 96 to the outside through the discharge silencer chamber 62 formed in the upper support member 54 through the discharge port (not shown) from the high pressure chamber side. At this time, the refrigerant is compressed to an appropriate supercritical pressure, and the refrigerant gas discharged from the refrigerant discharge pipe 96 flows into the gas cooler 154.
[0044]
The refrigerant gas flowing into the gas cooler 154 dissipates heat by the air cooling method and then passes through the internal heat exchanger 160. The refrigerant is further cooled by taking heat away from the low-pressure side refrigerant. Thereby, the cooling capacity of the refrigerant in the evaporator 157 is improved by the effect that the degree of supercooling of the refrigerant is increased.
[0045]
The high-pressure side refrigerant gas cooled by the internal heat exchanger 160 reaches the expansion valve 156. Note that the refrigerant gas is still in a gaseous state at the inlet of the expansion valve 156. The refrigerant is made into a gas / liquid two-phase mixture due to the pressure drop in the expansion valve 156 and flows into the evaporator 157 in this state. Therefore, the refrigerant evaporates and exhibits a cooling action by absorbing heat from the air.
[0046]
Thereafter, the refrigerant flows out of the evaporator 157 and passes through the internal heat exchanger 160. Therefore, heat is taken from the high-pressure side refrigerant and is subjected to a heating action. Thus, it evaporates with the evaporator 157, becomes low temperature, and the refrigerant | coolant which exited the evaporator 157 is not the state of a gas completely, but the state where the liquid was mixed. Therefore, by passing through the internal heat exchanger 160 and exchanging heat with the high-pressure side refrigerant, the refrigerant is superheated and becomes completely gas. Thereby, without providing an accumulator on the low pressure side, it is possible to reliably prevent the liquid back into 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.
[0047]
The refrigerant heated by the internal heat exchanger 160 repeats a cycle of being sucked into the first rotary compression element 32 of the compressor 10 from the refrigerant introduction pipe 94. At this time, in the normal operation state (at the time of pull-down) other than the start-up time (at the time of pull-down), the refrigerant pressure is stable without exceeding the design pressure (DP) of the refrigerant piping in the refrigerant circuit as shown in FIG. It is operated with the pressure.
[0048]
In this way, the bypass circuit 170 that connects the intermediate pressure region of the refrigerant circuit and the low pressure side, and the capillary tube 172 and the bypass valve 174 are provided in the bypass circuit 170 so that the bypass valve 174 is activated when the compressor 10 is started. Thus, by opening the flow path of the bypass circuit 170, the refrigerant gas in the intermediate pressure region can be released to the low pressure side. As a result, the refrigerant pressure in the intermediate pressure region decreases, and an increase in the pressure of the refrigerant gas compressed by the second rotary compression element 34 can be suppressed. For this reason, it is possible to avoid the inconvenience that the pressure of the refrigerant on the high-pressure side abnormally rises at the time of startup and the refrigerant pipe is deteriorated or worst-cased by the refrigerant gas.
[0049]
Thereby, the durability of the refrigerant cycle device can be ensured, and the reliability can be improved.
[0050]
Furthermore, since the refrigerant gas flowing into the bypass circuit 170 is decompressed by the capillary tube 172 provided in the bypass circuit 170 and then flows into the low pressure side, the refrigerant flows into the low pressure side, thereby increasing the low pressure. Thus, the inconvenience that the intermediate pressure further increases can be avoided.
[0051]
In this 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 passed. However, the present invention is not limited to this, for example, Alternatively, the flow path of the bypass circuit 170 may be opened until the refrigerant temperature or refrigerant pressure in the refrigerant circuit or the starting current of the compressor reaches a predetermined value. In addition, when the refrigerant flow to the bypass circuit is controlled by the refrigerant temperature in the refrigerant circuit, the refrigerant temperature is, for example, a refrigerant temperature sensor connected to a control device (not shown) for the evaporation temperature of the refrigerant in the evaporator 157. Detection may be performed so that the bypass valve 174 is opened from the time of activation and closed when the refrigerant evaporation temperature in the evaporator 157 detected by the refrigerant temperature sensor is lowered to a predetermined value.
[0052]
In the embodiment, the compressor 10 is described using an internal intermediate pressure type multi-stage (two-stage) compression rotary compressor. However, the compressor usable in the present invention is not limited to this, and the multi-stage of three or more stages is used. The present invention is effective even for a compression type compressor. In the present embodiment, the compressor 10 is operated at a constant speed. However, the present invention may be applied to an apparatus in which the rotation speed of the compressor is controlled by an inverter. In this case, since the rotation speed control at the time of starting can be performed more easily, the control function can be simplified.
[0053]
【The invention's effect】
As described above in detail, according to the refrigerant cycle device of the present invention, the intermediate cooling circuit for radiating the refrigerant discharged from the first compression element and sucked into the second compression element, the intermediate cooling circuit and the low pressure side preparative includes a bypass circuit that communicates, and a pressure reducing means and a valve device provided in the bypass circuit, intermediate cooling circuit, with provided so as to pass through the gas cooler, the compressor starts, the flow of the bypass circuit by the valve device Since the passage is opened, the intermediate pressure refrigerant compressed by the first compression element and flowing into the intermediate cooling circuit can be released from the bypass circuit to the low pressure side.
[0054]
Since the intermediate pressure of the refrigerant gas flows into the low pressure side, the intermediate pressure decreases, and the pressure on the high pressure side also decreases.Therefore, even when the compressor is operated at a constant speed, It is possible to avoid the inconvenience that the pressure increases abnormally, and to improve the durability and ensure smooth operation. Further, since the intermediate pressure refrigerant is decompressed by the decompression means provided in the bypass circuit and then flows into the low pressure side, it is possible to avoid the disadvantage that the pressure on the low pressure side is excessively increased.
[0055]
Further, since the intermediate pressure refrigerant is decompressed by the decompression means provided in the bypass circuit and then flows into the low pressure side, it is possible to avoid the disadvantage that the low pressure is excessively increased.
[0056]
In particular, since the intermediate cooling circuit is provided so as to pass through the gas cooler, the intermediate-pressure refrigerant compressed by the first compression element is cooled by the gas cooler and then merged with the low-pressure side refrigerant. It becomes possible to prevent the temperature from rising.
[0057]
In general, the durability and smooth operation can be ensured, and the reliability of the refrigerant cycle device can be improved.
[0058]
In particular, the present invention is suitable for a device using carbon dioxide having a very high pressure on the high pressure side as a refrigerant, and can also contribute to environmental problems if such carbon dioxide is used as a refrigerant.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a rotary compressor of an embodiment used in 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 graph showing changes 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 graph showing changes in refrigerant pressure in a conventional refrigerant cycle device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Multistage compression rotary compressor 12 Airtight container 14 Electric element 32 1st rotation compression element 34 2nd rotation 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、圧縮して前記ガスクーラに吐出する冷媒サイクル装置において、
前記第１の圧縮要素から吐出され、前記第２の圧縮要素に吸い込まれる冷媒を放熱させるための中間冷却回路と、
該中間冷却回路と低圧側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、
前記中間冷却回路は、前記ガスクーラを通過するよう設けられると共に、
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 refrigerant circuit is configured by sequentially connecting a compressor, a gas cooler, a throttle means, and an evaporator, and the compressor includes first and second compression elements driven by a driving element, and the low-pressure side of the refrigerant circuit The refrigerant cycle device that sucks and compresses the refrigerant from the first compression element and compresses the intermediate pressure refrigerant discharged from the first compression element into the second compression element, compresses it, and discharges it to the gas cooler In
An intermediate cooling circuit for releasing heat from the refrigerant discharged from the first compression element and sucked into the second compression element;
A bypass circuit communicating the intermediate cooling circuit and the low pressure side;
A pressure reducing means and a valve device provided in the bypass circuit,
The intermediate cooling circuit is provided to pass through the gas cooler,
A refrigerant cycle device that opens a flow path of the bypass circuit 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。  The refrigerant cycle device according to claim 1, wherein the valve device opens the flow path of the bypass circuit for a predetermined time after 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 after 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当該コンプレッサの駆動電流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。  The refrigerant cycle device according to claim 1, wherein the valve device opens the flow path of the bypass circuit until the compressor drive current reaches a predetermined value after 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。  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 after the compressor is started. 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。  6. The refrigerant cycle device according to claim 1, 2, 3, 4, or 5, wherein carbon dioxide is used as the refrigerant.
JP2003041197A 2003-02-19 2003-02-19 Refrigerant cycle equipment Expired - Fee Related JP4278402B2 (en)

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Cited By (1)

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CN102808768A (en) * 2011-06-03 2012-12-05 富士通将军股份有限公司 Rotary compressor

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JP2011047567A (en) * 2009-08-26 2011-03-10 Daikin Industries Ltd Refrigerating device
JP2011133208A (en) * 2009-12-25 2011-07-07 Sanyo Electric Co Ltd Refrigerating apparatus
DK2339266T3 (en) 2009-12-25 2018-05-28 Sanyo Electric Co Cooling device
GB2585594B (en) * 2018-03-26 2021-11-24 Mitsubishi Electric Corp Refrigeration device
CN112654823B (en) * 2018-09-14 2022-12-27 三菱电机株式会社 Heat source device and refrigeration cycle device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102808768A (en) * 2011-06-03 2012-12-05 富士通将军股份有限公司 Rotary compressor
CN102808768B (en) * 2011-06-03 2015-05-13 富士通将军股份有限公司 Rotary compressor

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