JP3847493B2

JP3847493B2 - Two-stage compression refrigeration system

Info

Publication number: JP3847493B2
Application number: JP24751599A
Authority: JP
Inventors: 浩業明石; 多佳雄吉村; 康祐坪井
Original assignee: 松下冷機株式会社
Priority date: 1999-09-01
Filing date: 1999-09-01
Publication date: 2006-11-22
Anticipated expiration: 2019-09-01
Also published as: JP2001074325A

Description

【０００１】
【発明の属する技術分野】
本発明は、２つの圧縮要素を持つ二段圧縮機を備えた二段圧縮冷凍冷蔵装置に関するものである。
【０００２】
【従来の技術】
冷凍機器分野において、低温熱源および高温熱源確保の一環として、高圧縮比運転に適した多段圧縮機を用いた二段圧縮冷凍装置が提案されている。従来の二段圧縮冷凍装置として、例えば特開平５−１３３３６８号公報に示されているものがある。
【０００３】
以下、図面を参照しながら上記従来の二段圧縮冷凍装置の一例について説明する。
【０００４】
図１１は従来の二段圧縮機を使用した二段圧縮冷凍サイクルの配管系統図である。
【０００５】
図１１において、１は二段圧縮機で、２は凝縮器、３は第１膨張弁、４は気液分離機、５は第２膨張弁、６は蒸発器、７はアキュムレータであり、これらが順次配管により接続されている。８は密閉容器であり、密閉容器８内の上部空間にはモーター９、その下部には二段圧縮機構１０が配置され、その外周部および底部が油溜１１として構成されている。二段圧縮機構１０は、上部の高段圧縮要素１２と下部の低段圧縮要素１３と両圧縮要素（１２，１３）の間に配置された平板形状の中板１４とからなる。１５は第１偏心部１５ａと第２偏心部１５ｂを持つクランクシャフトであり、モーター９のローター９ａに固定されている。１６、１７はクランクシャフト１５の第１偏心部１５ａと第２偏心部１５ｂに装着された第１ピストンおよび第２ピストンである。高段圧縮要素１２の気筒容積は、低段圧縮要素１３の気筒容積の約４５〜６５％に設定されている。低段圧縮要素１３の吐出側と高段圧縮要素１２の吸入側とは連通路１８を介して連通している。１９は冷媒インジェクション通路であり、連通路１８と気液分離機４の下流側とを連通している。
【０００６】
以上のように構成された二段圧縮冷凍装置について、以下その動作を説明する。
【０００７】
モーター３によってクランクシャフト１５が回転すると、低段圧縮要素１３はアキュームレータ７から冷媒ガスを吸入して圧縮し、連通路１８に吐出する。低段圧縮要素１３から連通路１８に吐出された冷媒ガスは、冷媒インジェクション通路１９からの冷媒ガスと混合して、高段圧縮要素１２の吸入側から吸入され、再び圧縮される。高段圧縮要素１２で圧縮された冷媒ガスは、密閉容器８内に一旦吐出された後に、配管を介して凝縮器２に送られる。凝縮器２で冷媒ガスは放熱して凝縮されて液冷媒になった後、第１膨張弁３により減圧される。そして、気液分離器４に流入し、一部はそこで蒸発する。これにより、気液分離器４内底部には液冷媒が貯溜され、気液分離器４内上部には一段膨張した飽和ガス冷媒が溜まる。そして、気液分離器４内からは液冷媒のみが第２膨張弁５方向に流出し、そこで減圧されて蒸発器６に流入して蒸発する。このときに周囲から熱を奪うことによって蒸発器６は冷却作用を発揮する。そして、蒸発器６を出た低温ガス冷媒はアキュームレータ７を経て二段圧縮機１に帰還し、再び低段圧縮要素１３に吸入される。
【０００８】
一方、気液分離器４内上部の飽和ガス冷媒は、冷媒インジェクション通路１９を経て連通路１８に流入する。そこで、低段圧縮要素１３から吐出された冷媒ガスの温度を下げるため、高段圧縮要素１２が吸入する冷媒ガスの温度を下げることができ、効率を向上することができる。また、高段圧縮要素１２の吐出ガスの温度も低くなるため、圧縮機の過熱を防止でき、潤滑油の粘度低下による潤滑不良や潤滑油の劣化を防止できる。
【０００９】
このように二段圧縮冷凍サイクルを使用した方が、一段圧縮冷凍サイクルを使用する場合よりも冷凍サイクルの効率が向上し、圧縮機の信頼性が向上する。
【００１０】
【発明が解決しようとする課題】
しかしながら上記従来の構成では、二段圧縮冷凍サイクルを、例えば冷凍冷蔵庫等の冷凍と冷蔵等の２つ以上の温度帯を必要とする装置に適用する場合には、最も温度の低い冷凍室の庫内温度が−１８℃〜−２２℃程度に設定されるため、蒸発器６の蒸発温度はそれより低い約−３０℃前後にする必要があった。一方、蒸発温度が高いほど圧縮機の効率は高くなるため、できるだけ蒸発温度を高く設計する必要があるが、前記した冷凍室の庫内温度の制限から蒸発温度はある値以下に制限される。このため、庫内温度が３℃〜７℃程度である冷蔵室の冷却にも、−３０℃前後の蒸発器６で冷却した低温の冷気を使用しなければならず、蒸発温度が低いため冷却システムの効率が悪くなることに加えて、冷蔵室庫内の温度制御の精度が悪くなると共に庫内各部の温度が不均一になるという欠点があった。
【００１１】
本発明は従来の課題を解決するもので、冷凍冷蔵装置の冷凍室と冷蔵室の各庫内温度に適した蒸発温度を持つ２つの蒸発器と二段圧縮機を備えることにより、各庫内の温度制御の精度を高めると共に庫内各部の温度の均一化が図れ、更に高効率で消費電力が少なく、また信頼性の高い二段圧縮冷凍冷蔵装置を提供することを目的とする。
【００１２】
また、上記従来の構成は、蒸発器６のみで冷却作用を得る必要があるために、気液分離器４から分流する冷媒循環量は冷媒インジェクション通路１９側よりも第２膨張弁５側の方が多くなる。そのため、二段圧縮機１の高段圧縮要素１２の気筒容積は低段圧縮要素１３の気筒容積の約４５〜６５％に設定されている。この二段圧縮機１を、冷凍冷蔵装置の冷凍室と冷蔵室の各庫内温度に適した２つの蒸発器を持つ冷凍サイクルに適用する場合には、高段圧縮要素１２の気筒容積が低段圧縮要素１３の気筒容積よりかなり小さいために、冷蔵室用の蒸発器の冷凍能力が小さくなり、冷凍室と冷蔵室を適正に冷却することができない可能性があるという欠点があった。
【００１３】
本発明の他の目的は、冷凍冷蔵装置の冷凍室と冷蔵室の各庫内温度に適した蒸発温度を持つ２つの蒸発器と二段圧縮機を備え、かつ高段圧縮要素の気筒容積と低段圧縮要素の気筒容積の比率を適正にすることにより、冷凍冷蔵装置の冷凍室と冷蔵室などの異なる温度帯の庫内のどちらか一方が冷凍能力不足になったり、冷凍能力過剰になること無く、各庫内を適正に冷却でき、かつ高効率で消費電力の少ない二段圧縮冷凍冷蔵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】
この目的を達成するために本発明は、密閉容器内にモーターと、ピストンがシリンダー内を往復運動する低段圧縮要素及び高段圧縮要素を備えた往復動式の二段圧縮機と、前記高段圧縮要素の吐出側と配管接続した凝縮器と、前記凝縮器の出口側と配管接続した中間圧用膨張装置と、前記低段圧縮要素の吐出側ならびに前記高段圧縮要素の吸入側と共に連通する中間圧用吸入パイプと、前記中間圧用膨張装置と前記中間圧用吸入パイプとの間に配管接続された中間圧用蒸発器と、前記凝縮器の出口側あるいは前記中間圧用膨張装置の出口側と配管接続した低圧用膨張装置と、前記低圧用膨張装置と前記二段圧縮機の低段圧縮要素の吸入側との間に配管接続された低圧用蒸発器とからなり、前記低段圧縮要素の吐出側と前記高段圧縮要素の吸入側とが前記密閉容器内に連通した構成としたのである。
【００１５】
これにより、冷凍冷蔵装置の２つの蒸発器はそれぞれ、冷凍室と冷蔵室等の各庫内温度に適した蒸発温度にすることができ、各庫内の温度制御の精度が高くなると共に庫内各部の温度の均一化が図れる。また、特に中間圧用蒸発器の蒸発温度を高く設定できるため圧縮機の効率が向上すると共に、各庫内を必要以上に温度の低い冷気で冷却することが無いため冷凍サイクル全体の効率が向上する。更に、密閉容器内が中間圧力になっているため、低段圧縮要素ならびに高段圧縮要素のそれぞれの圧縮室内と密閉容器内との圧力差が小さく、各圧縮要素と密閉容器内の間での冷媒ガスの漏れ量を少なくすることができ、二段圧縮機の冷凍能力、ならびに効率を向上することができる。
【００１６】
また、本発明は、密閉容器内にモーターと、ピストンがシリンダー内を往復運動する低段圧縮要素及び高段圧縮要素を備えた往復動式の二段圧縮機と、前記高段圧縮要素の吐出側と配管接続した凝縮器と、前記凝縮器の出口側と配管接続した中間圧用膨張装置と、前記低段圧縮要素の吐出側ならびに前記高段圧縮要素の吸入側と共に連通する中間圧用吸入パイプと、前記中間圧用膨張装置と前記中間圧用吸入パイプとの間に配管接続された中間圧用蒸発器と、前記凝縮器の出口側あるいは前記中間圧用膨張装置の出口側と配管接続した低圧用膨張装置と、前記低圧用膨張装置と前記二段圧縮機の低段圧縮要素の吸入側との間に配管接続された低圧用蒸発器とからなり、前記低段圧縮要素の吸入側が前記密閉容器内に連通した構成としたのである。
【００１７】
これにより、冷凍冷蔵装置の２つの蒸発器はそれぞれ、冷凍室と冷蔵室等の各庫内温度に適した蒸発温度にすることができ、各庫内の温度制御の精度が高くなると共に庫内各部の温度の均一化が図れる。また、特に中間圧用蒸発器の蒸発温度を高く設定できるため圧縮機の効率が向上すると共に、各庫内を必要以上に温度の低い冷気で冷却することが無いため冷凍サイクル全体の効率が向上する。更に、密閉容器内が低圧になっており、低圧用蒸発器から戻ってくる温度の低い冷媒ガスで密閉容器内の各圧縮要素やモータを冷却できるので、各圧縮要素の過熱を防止でき信頼性が向上すると共に、モータの温度低下によりモータ効率を向上することができる。
【００２０】
また、本発明は、低段圧縮要素の気筒容積ＶＬと高段圧縮要素の気筒容積ＶＨの比ＶＨ／ＶＬが０．５〜１．３の範囲に設定された構成としたのである。
【００２１】
これにより、冷凍冷蔵装置の２つの蒸発器はそれぞれ、冷凍室と冷蔵室等の各庫内温度に適した蒸発温度にすることができ、各庫内の温度制御の精度が高くなると共に庫内各部の温度の均一化が図れる。また、特に中間圧用蒸発器の蒸発温度を高く設定できるため圧縮機の効率が向上すると共に、各庫内を必要以上に温度の低い冷気で冷却することが無いため冷凍サイクル全体の効率が向上する。更に、高段圧縮要素の気筒容積と低段圧縮要素の気筒容積の比率を適正にすることにより、冷凍冷蔵装置の冷凍室と冷蔵室などの異なる温度帯の庫内のどちらか一方が冷凍能力不足になったり、冷凍能力過剰になること無く、各庫内を適正に冷却でき、かつ高効率で消費電力を少なくすることができる。また、高圧、低圧、中間圧の各圧力に応じた気筒容積の比率にすることにより、モータの最大トルクとトルク変動を小さくすることができ、モータ効率の向上と振動低減ができる。
【００２４】
【発明の実施の形態】
本発明の請求項１に記載の発明は、密閉容器内にモーターと、ピストンがシリンダー内を往復運動する低段圧縮要素及び高段圧縮要素を備えた往復動式の二段圧縮機と、前記高段圧縮要素の吐出側と配管接続した凝縮器と、前記凝縮器の出口側と配管接続した中間圧用膨張装置と、前記低段圧縮要素の吐出側ならびに前記高段圧縮要素の吸入側と共に連通する中間圧用吸入パイプと、前記中間圧用膨張装置と前記中間圧用吸入パイプとの間に配管接続された中間圧用蒸発器と、前記凝縮器の出口側あるいは前記中間圧用膨張装置の出口側と配管接続した低圧用膨張装置と、前記低圧用膨張装置と前記二段圧縮機の低段圧縮要素の吸入側との間に配管接続された低圧用蒸発器とからなり、前記低段圧縮要素の吐出側と前記高段圧縮要素の吸入側とが前記密閉容器内に連通した構成としたものであり、冷凍冷蔵装置の２つの蒸発器は、蒸発圧力がそれぞれ低圧と中間圧になるため、冷凍室と冷蔵室等の各庫内温度に適した蒸発器温度にそれぞれすることができ、各庫内の温度制御の精度が高くなると共に庫内各部の温度の均一化が図れる。また、特に中間圧用蒸発器の蒸発温度を高く設定できることから、圧縮機の効率が向上すると共に、各庫内を必要以上に温度の低い冷気で冷却することが無いため冷凍サイクル全体の効率が向上する。更に、低段圧縮要素の吐出側と高段圧縮要素の吸入側とが密閉容器内に連通しているため、密閉容器内が中間圧力になり、低段圧縮要素ならびに高段圧縮要素のそれぞれの圧縮室内と密閉容器内との圧力差が小さく、各圧縮要素と密閉容器内の間での冷媒ガスの漏れ量を少なくすることができ、二段圧縮機の冷凍能力、ならびに効率を向上することができるという作用を有する。
【００２５】
請求項２に記載の発明は、密閉容器内にモーターと、ピストンがシリンダー内を往復運動する低段圧縮要素及び高段圧縮要素を備えた往復動式の二段圧縮機と、前記高段圧縮要素の吐出側と配管接続した凝縮器と、前記凝縮器の出口側と配管接続した中間圧用膨張装置と、前記低段圧縮要素の吐出側ならびに前記高段圧縮要素の吸入側と共に連通する中間圧用吸入パイプと、前記中間圧用膨張装置と前記中間圧用吸入パイプとの間に配管接続された中間圧用蒸発器と、前記凝縮器の出口側あるいは前記中間圧用膨張装置の出口側と配管接続した低圧用膨張装置と、前記低圧用膨張装置と前記二段圧縮機の低段圧縮要素の吸入側との間に配管接続された低圧用蒸発器とからなり、前記低段圧縮要素の吸入側が前記密閉容器内に連通した構成としたものであり、冷凍冷蔵装置の２つの蒸発器は、蒸発圧力がそれぞれ低圧と中間圧になるため、冷凍室と冷蔵室等の各庫内温度に適した蒸発器温度にそれぞれすることができ、各庫内の温度制御の精度が高くなると共に庫内各部の温度の均一化が図れる。また、特に中間圧用蒸発器の蒸発温度を高く設定できることから、圧縮機の効率が向上すると共に、各庫内を必要以上に温度の低い冷気で冷却することが無いため冷凍サイクル全体の効率が向上する。更に、低段圧縮要素の吸入側が密閉容器内に連通しているため、密閉容器内が低圧になり、低圧用蒸発器から戻ってくる温度の低い冷媒ガスで密閉容器内の各圧縮要素やモータを冷却できるので、各圧縮要素の過熱を防止でき信頼性が向上すると共に、モータの温度低下によりモータ効率を向上することができるという作用を有する。
【００２７】
請求項３に記載の発明は、請求項１または請求項２に記載の発明に、さらに、低段圧縮要素の気筒容積ＶＬと高段圧縮要素の気筒容積ＶＨの比ＶＨ／ＶＬが０．５〜１．３の範囲に設定するように構成されたものであり、請求項1あるいは請求項２あるいは請求項３に記載の発明の作用に加えて、高段圧縮要素の気筒容積と低段圧縮要素の気筒容積の比率を適正にすることにより、冷凍冷蔵装置の冷凍室と冷蔵室などの異なる温度帯の庫内のどちらか一方が冷凍能力不足になったり、冷凍能力過剰になること無く、各庫内を適正に冷却でき、かつ高効率で消費電力を少なくするという作用を有する。また、高圧、低圧、中間圧の各圧力に応じた気筒容積の比率にすることにより、モータの最大トルクとトルク変動を小さくすることができ、モータ効率の向上と振動低減ができる。
【００２９】
【実施例】
以下、本発明による二段圧縮冷凍冷蔵装置の実施例について、図面を参照しながら説明する。尚、従来と同一構成については、同一符号を付して詳細な説明を省略する。
【００３０】
（実施例１）
図１は本発明の実施例１による二段圧縮冷凍冷蔵装置の冷媒回路図を示す。図２は同実施例の二段圧縮冷凍冷蔵装置に使用する二段圧縮機の平面断面図を示す。図３は同実施例の二段圧縮冷凍冷蔵装置に使用する二段圧縮機の縦断面図を示す。図4は同実施例の二段圧縮冷凍冷蔵装置における冷凍サイクルの圧力−エンタルピ線図である。
【００３１】
図１、図２、図3、図4において、２０は、密閉容器２１内にモーター２２と低段圧縮要素２３と高段圧縮要素２４とを備えた二段圧縮機である。２５は高段圧縮要素２４の吐出側と配管接続した凝縮器であり、２６は凝縮器２５の出口側と配管接続した中間圧用膨張装置である。２７は低段圧縮要素２３の吐出側ならびに高段圧縮要素２４の吸入側と共に連通する中間圧用吸入パイプであり、２８は中間圧用膨張装置２６と中間圧用吸入パイプ２７との間に配管接続された中間圧用蒸発器である。２９は凝縮器２５の出口側と配管接続した低圧用膨張装置であり、３０は低圧用膨張装置２９と二段圧縮機２０の低段圧縮要素２３の吸入側との間に配管接続された低圧用蒸発器である。低段圧縮要素２３の吐出側と高段圧縮要素２４の吸入側は密閉容器２１内に連通している。
【００３２】
低段圧縮要素２３は、シリンダー３１、ピストン３２、コンロッド３３、吸入マフラー３４、吐出マフラー３５等からなり、高段圧縮要素２４も同様にシリンダー３６、ピストン３７、コンロッド３８、吸入マフラー３９、吐出マフラー４０等からなる。モーター２２は、クランクシャフト４１に固定されたローター４２、ステーター４３により構成されている。クランクシャフト４１は偏心部４１ａを有し、偏心部４１ａとピストン３２、３７はそれぞれコンロッド３３、３８により連結されている。４２は密閉容器２１に固定され、吸入マフラー３４と低圧用蒸発器３０を連通する低圧用吸入パイプである。４３は密閉容器２１に固定された吐出パイプであり、一端が吐出管４４を介して吐出マフラー４０に連通し、他端が配管を介して凝縮器２５に連通している。４５は潤滑油で、密閉容器２１の下部に貯溜している。
【００３３】
以上のように構成された密閉型圧縮機について、以下その動作を説明する。
【００３４】
モーター２２によってクランクシャフト４１が回転すると、コンロッド３３、３８によりピストン３２、３７はそれぞれシリンダー３１、３６内を往復運動する。そして、低段圧縮要素２３は、低圧用蒸発器３０から低圧用吸入パイプ４２、吸入マフラー３４を介してシリンダー３１内に冷媒ガスを吸入した後、中間圧まで圧縮して吐出マフラー３５を介して密閉容器２１内に吐出する。吐出マフラー３５から吐出された冷媒ガスは、中間圧用吸入パイプ２７から密閉容器２１内に流入する冷媒ガスと混合して、高段圧縮要素２４の吸入マフラー３９からシリンダー３６内に吸入され、再び圧縮される。高段圧縮要素２４で圧縮された冷媒ガスは、吐出マフラー４０、吐出管４４、吐出パイプ４３を通って凝縮器２５に送られる。凝縮器２５で冷媒ガスは放熱して凝縮されて液冷媒になった後、２つの流路に分かれる。一方は、中間圧用膨張装置２６に流れて減圧され、中間圧用蒸発器２８に流入して蒸発する。このときに周囲から熱を奪うことによって中間圧用蒸発器２８は冷却作用を発揮する。そして、中間圧用蒸発器２８を出た冷媒ガスは中間圧用吸入パイプ２７を経て二段圧縮機１に帰還する。
【００３５】
凝縮器２５からの他方の液冷媒は、低圧用膨張装置２９に流れて減圧され、低圧用蒸発器３０に流入して蒸発する。このときに周囲から熱を奪うことによって低圧用蒸発器２８は冷却作用を発揮する。そして、低圧用蒸発器３０を出た冷媒ガスは低圧用吸入パイプ４２を経て二段圧縮機１に帰還し、再び低段圧縮要素２３に吸入される。
【００３６】
また、潤滑油４５はクランクシャフト４１の下端部から遠心力によって吸い上げられ、クランクシャフト４１の各摺動部を潤滑した後、偏心部４１ａの上端部から遠心力によって飛散して、ピストン３２、３７とシリンダー３１、３６の摺動部やコンロッド３３、３８の摺動部を潤滑する。
【００３７】
本実施例の冷凍サイクルは図４に示されるように、中間圧用蒸発器２８内の冷媒は中間圧に、低圧用蒸発器３０内の冷媒は低圧になる。この冷凍サイクルを冷凍冷蔵装置に適用する場合、中間圧用蒸発器２８を冷蔵用に使用し、低圧用蒸発器３０を冷凍用に使用する。そのため、冷凍室と冷蔵室等の各庫内温度に適した蒸発器温度にそれぞれすることができる。例えば、冷蔵室の温度を３℃〜７℃、冷凍室の温度を−１８℃〜−２２℃に設定する場合には、中間圧用蒸発器２８の蒸発温度を０℃〜−１０℃程度に、低圧用蒸発器３０の蒸発温度を−２５℃〜−３５℃程度に設定することができ、各庫内の温度と蒸発温度の差が小さいため、各庫内の温度制御の精度が高くなると共に庫内各部の温度の均一化が図れる。また、特に中間圧用蒸発器２８の蒸発温度を高く設定できることから、二段圧縮機２０の効率が向上すると共に、各庫内を必要以上に温度の低い冷気で冷却することが無いため冷凍サイクル全体の効率が向上する。
【００３８】
更に、低段圧縮要素２３の吐出側と高段圧縮要素２４の吸入側とが密閉容器２０内に連通しているため、密閉容器２０内が中間圧力になり、低段圧縮要素２３ならびに高段圧縮要素２４のそれぞれのシリンダー３１、３６内と密閉容器２１内との圧力差が小さく、各圧縮要素と密閉容器２１内の間での冷媒ガスの漏れ量を少なくすることができ、二段圧縮機２０の冷凍能力、ならびに効率を向上することができる。
【００３９】
以上のように本実施例の二段圧縮冷凍冷蔵装置は、密閉容器２１内にモーター２２と低段圧縮要素２３と高段圧縮要素２４とを備えた二段圧縮機２０と、高段圧縮要素２４の吐出側と配管接続した凝縮器２５と、凝縮器２５の出口側と配管接続した中間圧用膨張装置２６と、低段圧縮要素２３の吐出側ならびに高段圧縮要素２４の吸入側と共に連通する中間圧用吸入パイプ２７と、中間圧用膨張装置２６と中間圧用吸入パイプ２７との間に配管接続された中間圧用蒸発器２８と、凝縮器２５の出口側あるいは中間圧用膨張装置２６の出口側と配管接続した低圧用膨張装置２９と、低圧用膨張装置２９と二段圧縮機２０の低段圧縮要素２３の吸入側との間に配管接続された低圧用蒸発器３０とからなり、低段圧縮要素２３の吐出側と高段圧縮要素２４の吸入側とが密閉容器２１内に連通した構成となっているので、各庫内の温度制御の精度を高めると共に庫内各部の温度の均一化が図れ、更に高効率で消費電力が少ない二段圧縮冷凍冷蔵装置とすることができる。
【００４０】
（実施例２）
図５は本発明の実施例２による二段圧縮冷凍冷蔵装置の冷媒回路図を示す。図６は同実施例の二段圧縮冷凍冷蔵装置に使用する二段圧縮機の平面断面図を示す。
【００４１】
以下、図面を参照しながら説明するが、実施例１と同一構成については、同一符号を付して詳細な説明を省略する。図５、図６において、４６は、低段圧縮要素４７と高段圧縮要素４８とを備えた二段圧縮機である。４９は低段圧縮要素４７の吐出側ならびに高段圧縮要素４８の吸入側と共に連通する中間圧用吸入パイプである。５０は密閉容器２１に固定された低圧用吸入パイプであり、低圧用蒸発器３０と密閉容器２１内を連通している。また、低段圧縮要素４７の吸入側は吸入マフラー５１から密閉容器２１内に連通している。５２は高段圧縮要素４８の吸入マフラーであり、中間圧用吸入パイプ４９と連通している。５３は吐出マフラー５４と吸入マフラー５２を連通する連通管である。
【００４２】
以上のように構成された二段圧縮冷凍冷蔵装置について、以下その動作を説明する。
【００４３】
二段圧縮機４６の内部構成以外は実施例１と同じなので、本冷凍サイクルによる効果は実施例１とほぼ同様に得られる。すなわち、各庫内の温度制御の精度を高めると共に庫内各部の温度の均一化が図れ、更に高効率で消費電力を少なくすることができる。
【００４４】
本実施例では、低段圧縮要素４７の吸入側が密閉容器２１内に連通しているため、密閉容器２１内が低圧になり、低圧用蒸発器３０から戻ってくる温度の低い冷媒ガスで密閉容器２１内の低段圧縮要素４７、高段圧縮要素４８やモータ２２を冷却できるので、各圧縮要素４７、４８の過熱を防止でき信頼性が向上すると共に、モータ２２の温度低下によりモータ効率を向上することができる。
【００４５】
以上のように本実施例の二段圧縮冷凍冷蔵装置は、密閉容器２１内にモーター２２と低段圧縮要素４７と高段圧縮要素４８とを備えた二段圧縮機４６と、高段圧縮要素４８の吐出側と配管接続した凝縮器２８と、凝縮器２８の出口側と配管接続した中間圧用膨張装置２６と、低段圧縮要素４７の吐出側ならびに高段圧縮要素４８の吸入側と共に連通する中間圧用吸入パイプ４９と、中間圧用膨張装置２６と中間圧用吸入パイプ４９との間に配管接続された中間圧用蒸発器２８と、凝縮器２５の出口側あるいは中間圧用膨張装置２６の出口側と配管接続した低圧用膨張装置２９と、低圧用膨張装置２９と二段圧縮機４６の低段圧縮要素４７の吸入側との間に配管接続された低圧用蒸発器３０とからなり、低段圧縮要素４７の吸入側が密閉容器２１内に連通した構成となっているので、各庫内の温度制御の精度を高めると共に庫内各部の温度の均一化が図れ、更に高効率で消費電力を少なくすることができ、更に二段圧縮機４６の信頼性を向上させ、モータ効率を向上することができる。
【００４６】
（実施例３）
図７は本発明の実施例３による二段圧縮冷凍冷蔵装置の冷媒回路図を示す。図８は同実施例の二段圧縮冷凍冷蔵装置に使用する二段圧縮機の平面断面図を示す。
【００４７】
以下、図面を参照しながら説明するが、実施例１と同一構成については、同一符号を付して詳細な説明を省略する。図８、図９において、５５は、低段圧縮要素５６と高段圧縮要素５７とを備えた二段圧縮機である。５８は低段圧縮要素５６の吐出側ならびに高段圧縮要素５７の吸入側と共に連通する中間圧用吸入パイプである。５９は高段圧縮要素５７の吸入マフラーであり、中間圧用吸入パイプ５８と連通している。６０は吐出マフラー６１と吸入マフラー５９を連通する連通管である。６２は密閉容器２１に固定された吐出パイプであり、一端が密閉容器２１内に連通し、他端が配管を介して凝縮器２５に連通している。また、高段圧縮要素５７の吐出側は吐出マフラー６３から密閉容器２１内に連通している。
【００４８】
以上のように構成された二段圧縮冷凍冷蔵装置について、以下その動作を説明する。
【００４９】
二段圧縮機５５の内部構成以外は実施例１と同じなので、本冷凍サイクルによる効果は実施例１とほぼ同様に得られる。すなわち、各庫内の温度制御の精度を高めると共に庫内各部の温度の均一化が図れ、更に高効率で消費電力を少なくすることができる。
【００５０】
本実施例では、高段圧縮要素５７の吐出側が密閉容器２１内に連通しているため、密閉容器２１内が高圧になり、密閉容器２１内の圧力がシリンダー３１、３６内の圧力よりも高くなる。そのため、クランクシャフト４１の偏心部４１ａからシリンダー３１、３６部に飛散した潤滑油４５は、圧力差によりシリンダー３１、３６とピストン３２、３７のそれぞれの隙間に流入して、ピストン３２、３７とシリンダー３１、３６等の摺動部の潤滑性が向上して信頼性を向上することができる。
【００５１】
以上のように本実施例の二段圧縮冷凍冷蔵装置は、密閉容器２１内にモーター２２と低段圧縮要素５６と高段圧縮要素５７とを備えた二段圧縮機５５と、高段圧縮要素５７の吐出側と配管接続した凝縮器２５と、凝縮器２５の出口側と配管接続した中間圧用膨張装置２６と、低段圧縮要素５６の吐出側ならびに高段圧縮要素５７の吸入側と共に連通する中間圧用吸入パイプ５８と、中間圧用膨張装置２６と中間圧用吸入パイプ５８との間に配管接続された中間圧用蒸発器２８と、凝縮器２５の出口側あるいは中間圧用膨張装置２６の出口側と配管接続した低圧用膨張装置２９と、低圧用膨張装置２９と二段圧縮機５５の低段圧縮要素５６の吸入側との間に配管接続された低圧用蒸発器３０とからなり、高段圧縮要素５７の吐出側が密閉容器２１内に連通した構成となっているので、各庫内の温度制御の精度を高めると共に庫内各部の温度の均一化が図れ、更に高効率で消費電力を少なくすることができ、更に圧力差により密閉容器２１内から低段圧縮要素５６ならびに高段圧縮要素５７それぞれのシリンダー３１、３６内への潤滑油４５の供給が十分にでき、ピストン３２、３７とシリンダー３１、３６等の摺動部の潤滑性が向上して信頼性を向上することができる。
【００５２】
（実施例４）
図９は本発明の実施例４による二段圧縮冷凍冷蔵装置に使用する二段圧縮機の縦断面図を示す。
【００５３】
以下、図面を参照しながら説明するが、実施例１あるいは実施例２あるいは実施例３と同一構成については、同一符号を付して詳細な説明を省略する。図９において、６４は、低段圧縮要素６５と高段圧縮要素６６とを備えた二段圧縮機である。低段圧縮要素６５は、シリンダー６６、ピストン６７、コンロッド６８、吸入マフラー３４、吐出マフラー３５等からなり、高段圧縮要素６６も同様にシリンダー６９、ピストン７０、コンロッド７１、吸入マフラー３９、吐出マフラー４０等からなる。低段圧縮要素６５の気筒容積ＶＬと高段圧縮要素６６の気筒容積ＶＨの比ＶＨ／ＶＬは０．５〜１．３の範囲に設定されている。
【００５４】
以上のように構成された二段圧縮冷凍冷蔵装置について、以下その動作を説明する。
【００５５】
二段圧縮機６４の気筒容積の比ＶＨ／ＶＬ以外は実施例１あるいは実施例２あるいは実施例３と同じなので、本冷凍サイクルによる効果は実施例１あるいは実施例２あるいは実施例３とほぼ同様に得られる。すなわち、各庫内の温度制御の精度を高めると共に庫内各部の温度の均一化が図れ、更に高効率で消費電力が少なく、また信頼性を高くすることができる。
【００５６】
本実施例では、低段圧縮要素６５の気筒容積ＶＬと高段圧縮要素６９の気筒容積ＶＨの比ＶＨ／ＶＬは０．５〜１．３の範囲に設定しており、その効果を以下に説明する。
【００５７】
一般に冷凍冷蔵庫は、冷凍室の庫内容積に対する冷蔵室の庫内容積の比率は、１．５〜４．０程度になり冷蔵室の方が大きいが、冷凍室の方をより低温にすることから必要な冷凍能力はこの比率より小さくなる。そのため、冷凍室の必要冷凍能力に対する冷蔵室の必要冷凍能力の比は、０．５〜１．１程度になる。
【００５８】
例えば、パーシャル室等を含めた冷蔵室の温度を−５℃〜７℃、冷凍室の温度を−２２℃〜−１８℃に設定する場合には、中間圧用蒸発器２８の蒸発温度を−２０℃〜０℃程度に、低圧用蒸発器３０の蒸発温度を−３５℃〜−２５℃程度に設定する。これらの蒸発温度のときに、冷凍室と冷蔵室との冷凍能力の比率を前記した０．５〜１．１にする場合には、発明者の検討によれば、低段圧縮要素６５の気筒容積ＶＬと高段圧縮要素６９の気筒容積ＶＨの比ＶＨ／ＶＬは０．５〜１．３にすれば良いことが計算と実験から分かっている。
【００５９】
ＶＨ／ＶＬの値が小さ過ぎると、高段圧縮側の冷媒循環量が減少し、中間圧用蒸発器２８の冷凍能力が小さくなって、冷蔵室の庫内温度が上昇する等の悪影響が現れる。一方、ＶＨ／ＶＬの値が大き過ぎると、低段圧縮側の冷媒循環量が減少し、低圧用蒸発器３０の冷凍能力が小さくなって、冷凍室の庫内温度が上昇する等の悪影響が現れる。
【００６０】
従って、高段圧縮要素６６の気筒容積と低段圧縮要素６４の気筒容積の比率を適正にすることにより、冷凍冷蔵装置の冷凍室と冷蔵室などの異なる温度帯の庫内のどちらか一方が冷凍能力不足になったり、冷凍能力過剰になること無く、各庫内を適正に冷却でき、かつ高効率で消費電力を少なくすることができる。
【００６１】
更に、圧縮機運転中において、高圧と中間圧の差圧が中間圧と低圧の差圧より大きい場合は、高段圧縮要素６６の気筒容積を低段圧縮要素６４の気筒容積より小さくすることにより、高段圧縮要素６６の圧縮に必要なトルクと低段圧縮要素６４の圧縮に必要なトルクの差が小さくなり、モータ２２の最大トルクとトルク変動を小さくすることができ、モータ効率の向上と振動低減ができる。この場合、各気筒容積の調整はピストン６７、７０の外径の変更により行う。また、逆に高圧と中間圧の差圧が中間圧と低圧の差圧より小さい場合は、高段圧縮要素６６の気筒容積を低段圧縮要素６４の気筒容積より大きくすることにより、同様の効果が得られる。
【００６２】
以上のように本実施例の二段圧縮冷凍冷蔵装置は、低段圧縮要素６５の気筒容積ＶＬと高段圧縮要素６６の気筒容積ＶＨの比ＶＨ／ＶＬが０．５〜１．３の範囲に設定された構成となっているので、実施例１あるいは実施例２あるいは実施例３の効果に加えて、冷凍冷蔵装置の冷凍室と冷蔵室などの異なる温度帯の庫内のどちらか一方が冷凍能力不足になったり、冷凍能力過剰になること無く、各庫内を適正に冷却でき、かつ高効率で消費電力を少なくすることができる。また、高圧、低圧、中間圧の各圧力に応じた気筒容積の比率にすることにより、モータ２２の最大トルクとトルク変動を小さくすることができ、モータ効率の向上と振動低減ができる。
【００６３】
（実施例５）
図１０は本発明の実施例５による二段圧縮冷凍冷蔵装置に使用する二段圧縮機の平面断面図を示す。
【００６４】
以下、図面を参照しながら説明するが、実施例１と同一構成については、同一符号を付して詳細な説明を省略する。図１０において、７２は、低段圧縮要素２３と高段圧縮要素７３とを備えた二段圧縮機である。７４は低段圧縮要素２３の吐出側ならびに高段圧縮要素７３の吸入側と共に連通する中間圧用吸入パイプである。７５は高段圧縮要素７３の吸入マフラーである。中間圧用吸入パイプ７４の密閉容器２１内への開口部が高段側圧縮要素７３の吸入マフラー７５にわずかな隙間を介して連通している。
【００６５】
以上のように構成された二段圧縮冷凍冷蔵装置について、以下その動作を説明する。
【００６６】
二段圧縮機４６の内部構成以外は実施例１と同じなので、本冷凍サイクルによる効果は実施例１とほぼ同様に得られる。すなわち、各庫内の温度制御の精度を高めると共に庫内各部の温度の均一化が図れ、更に高効率で消費電力を少なくすることができる。
【００６７】
本実施例では、中間圧用吸入パイプ７４の密閉容器２１内への開口部が高段側圧縮要素７３の吸入マフラー７５にわずかな隙間を介して連通しているため、中間圧用蒸発器２８から中間圧用吸入パイプ７４を通って密閉容器２１内に戻ってきた冷媒ガスは、わずかな隙間を介して高段圧縮要素７３の吸入側にある吸入マフラー７５に吸入される。そのため、冷媒ガスは、低段圧縮要素２３や高段圧縮要素７３やモータ２２からの受熱の影響が小さく、温度上昇が小さく抑えられる。従って、吸入される冷媒ガスの密度が大きくなり、冷媒循環量が多くなると共に効率を向上することができる。
【００６８】
更に、中間圧用吸入パイプ７４と高段圧縮要素７３の吸入側が直接接続される場合に比べて、わずかな隙間があるために高段圧縮要素７３からの圧力脈動は密閉容器２１内に拡散し、中間圧用吸入パイプ７４に伝わり難く、騒音の発生を防止できる。
【００６９】
以上のように本実施例の二段圧縮冷凍冷蔵装置は、中間圧用吸入パイプ７４の密閉容器２１内への開口部が高段側圧縮要素７３の吸入側にわずかな隙間を介して連通する構成となっているので、実施例１の効果に加えて、中間圧用蒸発器２８から中間圧用吸入パイプ７４を通って密閉容器２１内に戻ってきた冷媒ガスは、わずかな隙間を介して高段圧縮要素７３の吸入側に吸入されるため、各圧縮要素やモータ２２からの受熱の影響が小さく、温度上昇が小さく抑えられる。そのため、吸入される冷媒ガスの密度が大きくなり、冷媒循環量が多くなると共に効率を向上することができる。更に、高段圧縮要素からの圧力脈動は密閉容器内に拡散し、中間圧用吸入パイプに伝わり難く、騒音の発生を防止できる。
【００７０】
【発明の効果】
以上説明したように請求項１に記載の発明は、密閉容器内にモーターと、ピストンがシリンダー内を往復運動する低段圧縮要素及び高段圧縮要素を備えた往復動式の二段圧縮機と、前記高段圧縮要素の吐出側と配管接続した凝縮器と、前記凝縮器の出口側と配管接続した中間圧用膨張装置と、前記低段圧縮要素の吐出側ならびに前記高段圧縮要素の吸入側と共に連通する中間圧用吸入パイプと、前記中間圧用膨張装置と前記中間圧用吸入パイプとの間に配管接続された中間圧用蒸発器と、前記凝縮器の出口側あるいは中間圧用膨張装置の出口側と配管接続した低圧用膨張装置と、前記低圧用膨張装置と前記二段圧縮機の前記低段圧縮要素の吸入側との間に配管接続された低圧用蒸発器とからなり、前記低段圧縮要素の吐出側と前記高段圧縮要素の吸入側とが密閉容器内に連通した構成となっているので、冷凍冷蔵装置の２つの蒸発器はそれぞれ、冷凍室と冷蔵室等の各庫内温度に適した蒸発温度にすることができ、各庫内の温度制御の精度が高くなると共に庫内各部の温度の均一化が図れる。また、特に中間圧用蒸発器の蒸発温度を高く設定できるため圧縮機の効率が向上すると共に、各庫内を必要以上に温度の低い冷気で冷却することが無いため冷凍サイクル全体の効率が向上する。更に、密閉容器内が中間圧力になっているため、低段圧縮要素ならびに高段圧縮要素のそれぞれの圧縮室内と密閉容器内との圧力差が小さく、各圧縮要素と密閉容器内の間での冷媒ガスの漏れ量を少なくすることができ、二段圧縮機の冷凍能力、ならびに効率を向上することができる。
【００７１】
また、請求項２に記載の発明は、密閉容器内にモーターと、ピストンがシリンダー内を往復運動する低段圧縮要素及び高段圧縮要素を備えた往復動式の二段圧縮機と、前記高段圧縮要素の吐出側と配管接続した凝縮器と、前記凝縮器の出口側と配管接続した中間圧用膨張装置と、前記低段圧縮要素の吐出側ならびに前記高段圧縮要素の吸入側と共に連通する中間圧用吸入パイプと、前記中間圧用膨張装置と前記中間圧用吸入パイプとの間に配管接続された中間圧用蒸発器と、前記凝縮器の出口側あるいは前記中間圧用膨張装置の出口側と配管接続した低圧用膨張装置と、前記低圧用膨張装置と前記二段圧縮機の前記低段圧縮要素の吸入側との間に配管接続された低圧用蒸発器とからなり、前記低段圧縮要素の吸入側が前記密閉容器内に連通した構成となっているので、冷凍冷蔵装置の２つの蒸発器は、蒸発圧力がそれぞれ低圧と中間圧になるため、冷凍室と冷蔵室等の各庫内温度に適した蒸発器温度にそれぞれすることができ、各庫内の温度制御の精度が高くなると共に庫内各部の温度の均一化が図れる。また、特に中間圧用蒸発器の蒸発温度を高く設定できることから、圧縮機の効率が向上すると共に、各庫内を必要以上に温度の低い冷気で冷却することが無いため冷凍サイクル全体の効率が向上する。更に、低段圧縮要素の吸入側が密閉容器内に連通しているため、密閉容器内が低圧になり、低圧用蒸発器から戻ってくる温度の低い冷媒ガスで密閉容器内の各圧縮要素やモータを冷却できるので、各圧縮要素の過熱を防止でき信頼性が向上すると共に、モータの温度低下によりモータ効率を向上することができる。
【００７３】
また、請求項３に記載の発明は、請求項１または請求項２に記載の発明に加えて、低段圧縮要素の気筒容積ＶＬと高段圧縮要素の気筒容積ＶＨの比ＶＨ／ＶＬが０．５〜１．３の範囲に設定された構成となっているので、更に、冷凍冷蔵装置の冷凍室と冷蔵室などの異なる温度帯の庫内のどちらか一方が冷凍能力不足になったり、冷凍能力過剰になること無く、各庫内を適正に冷却でき、かつ高効率で消費電力を少なくすることができる。また、高圧、低圧、中間圧の各圧力に応じた気筒容積の比率にすることにより、モータの最大トルクとトルク変動を小さくすることができ、モータ効率の向上と振動低減ができる。
【図面の簡単な説明】
【図１】本発明による二段圧縮冷凍冷蔵装置の実施例１の冷媒回路図
【図２】同実施例の二段圧縮冷凍冷蔵装置に使用する二段圧縮機の平面断面図
【図３】同実施例の二段圧縮冷凍冷蔵装置に使用する二段圧縮機の縦断面図
【図４】同実施例の二段圧縮冷凍冷蔵装置における冷凍サイクルの圧力−エンタルピ線図
【図５】本発明による二段圧縮冷凍冷蔵装置の実施例２の冷媒回路図
【図６】同実施例の二段圧縮冷凍冷蔵装置に使用する二段圧縮機の平面断面図
【図７】本発明による二段圧縮冷凍冷蔵装置の実施例３の冷媒回路図
【図８】同実施例の二段圧縮冷凍冷蔵装置に使用する二段圧縮機の平面断面図
【図９】本発明による二段圧縮冷凍冷蔵装置の実施例４における二段圧縮機の縦断面図
【図１０】本発明による二段圧縮冷凍冷蔵装置の実施例５における二段圧縮機の平面断面図
【図１１】従来の二段圧縮機を使用した二段圧縮冷凍サイクルの配管系統図
【符号の説明】
２０二段圧縮機
２１密閉容器
２２モータ
２３低段圧縮要素
２４高段圧縮要素
２５凝縮器
２６中間圧用膨張装置
２７中間圧用吸入パイプ
２８中間圧用蒸発器
２９低圧用膨張装置
３０低圧用蒸発器
４６二段圧縮機
４７低段圧縮要素
４８高段圧縮要素
４９中間圧用吸入パイプ
５５二段圧縮機
５６低段圧縮要素
５７高段圧縮要素
５８中間圧用吸入パイプ
６４二段圧縮機
６５低段圧縮要素
６６高段圧縮要素
７２二段圧縮機
７３高段圧縮要素
７４中間圧用吸入パイプ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-stage compression refrigeration apparatus provided with a two-stage compressor having two compression elements.
[0002]
[Prior art]
In the field of refrigeration equipment, as a part of securing a low temperature heat source and a high temperature heat source, a two-stage compression refrigeration apparatus using a multistage compressor suitable for high compression ratio operation has been proposed. An example of a conventional two-stage compression refrigeration apparatus is disclosed in Japanese Patent Laid-Open No. 5-133368.
[0003]
Hereinafter, an example of the conventional two-stage compression refrigeration apparatus will be described with reference to the drawings.
[0004]
FIG. 11 is a piping system diagram of a two-stage compression refrigeration cycle using a conventional two-stage compressor.
[0005]
In FIG. 11, 1 is a two-stage compressor, 2 is a condenser, 3 is a first expansion valve, 4 is a gas-liquid separator, 5 is a second expansion valve, 6 is an evaporator, and 7 is an accumulator. Are sequentially connected by piping. Reference numeral 8 denotes a sealed container. A motor 9 is disposed in the upper space of the sealed container 8, a two-stage compression mechanism 10 is disposed in the lower portion thereof, and an outer peripheral portion and a bottom portion are configured as an oil reservoir 11. The two-stage compression mechanism 10 includes an upper high-stage compression element 12, a lower low-stage compression element 13, and a flat plate-shaped intermediate plate 14 disposed between both compression elements (12, 13). Reference numeral 15 denotes a crankshaft having a first eccentric portion 15 a and a second eccentric portion 15 b, and is fixed to the rotor 9 a of the motor 9. Reference numerals 16 and 17 denote a first piston and a second piston mounted on the first eccentric portion 15a and the second eccentric portion 15b of the crankshaft 15, respectively. The cylinder volume of the high stage compression element 12 is set to about 45 to 65% of the cylinder volume of the low stage compression element 13. The discharge side of the low-stage compression element 13 and the suction side of the high-stage compression element 12 communicate with each other via a communication path 18. A refrigerant injection passage 19 communicates the communication passage 18 and the downstream side of the gas-liquid separator 4.
[0006]
The operation of the two-stage compression refrigeration apparatus configured as described above will be described below.
[0007]
When the crankshaft 15 is rotated by the motor 3, the low-stage compression element 13 sucks and compresses the refrigerant gas from the accumulator 7 and discharges it to the communication path 18. The refrigerant gas discharged from the low-stage compression element 13 to the communication path 18 is mixed with the refrigerant gas from the refrigerant injection path 19 and is sucked from the suction side of the high-stage compression element 12 and compressed again. The refrigerant gas compressed by the high-stage compression element 12 is once discharged into the sealed container 8 and then sent to the condenser 2 via the pipe. The refrigerant gas radiates heat in the condenser 2 and is condensed to form a liquid refrigerant, and then decompressed by the first expansion valve 3. And it flows into the gas-liquid separator 4 and a part evaporates there. As a result, the liquid refrigerant is stored at the inner bottom of the gas-liquid separator 4, and the saturated gas refrigerant expanded one stage is stored at the upper portion of the gas-liquid separator 4. Then, only the liquid refrigerant flows out from the gas-liquid separator 4 in the direction of the second expansion valve 5, where the pressure is reduced and the refrigerant flows into the evaporator 6 and evaporates. At this time, the evaporator 6 exerts a cooling action by removing heat from the surroundings. Then, the low-temperature gas refrigerant exiting the evaporator 6 returns to the two-stage compressor 1 through the accumulator 7 and is sucked into the low-stage compression element 13 again.
[0008]
On the other hand, the saturated gas refrigerant in the upper part of the gas-liquid separator 4 flows into the communication path 18 via the refrigerant injection path 19. Therefore, since the temperature of the refrigerant gas discharged from the low-stage compression element 13 is lowered, the temperature of the refrigerant gas sucked by the high-stage compression element 12 can be lowered, and the efficiency can be improved. Further, since the temperature of the gas discharged from the high-stage compression element 12 is also reduced, overheating of the compressor can be prevented, and poor lubrication and deterioration of the lubricating oil due to a decrease in the viscosity of the lubricating oil can be prevented.
[0009]
Thus, using the two-stage compression refrigeration cycle improves the efficiency of the refrigeration cycle and improves the reliability of the compressor as compared with the case of using the one-stage compression refrigeration cycle.
[0010]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, when the two-stage compression refrigeration cycle is applied to an apparatus that requires two or more temperature zones, such as freezing and refrigeration, for example, a refrigerator-freezer, the freezer compartment having the lowest temperature is stored. Since the internal temperature is set to about −18 ° C. to −22 ° C., the evaporation temperature of the evaporator 6 needs to be about −30 ° C., which is lower than that. On the other hand, the higher the evaporating temperature, the higher the efficiency of the compressor. Therefore, it is necessary to design the evaporating temperature as high as possible, but the evaporating temperature is limited to a certain value or less due to the limitation of the inside temperature of the freezer. For this reason, low temperature cold air cooled by the evaporator 6 at around −30 ° C. must also be used for cooling the refrigerator compartment where the internal temperature is about 3 ° C. to 7 ° C., and the cooling temperature is low. In addition to the inefficiency of the system, there is a drawback that the temperature control accuracy in the refrigerator compartment is deteriorated and the temperature of each part in the refrigerator becomes non-uniform.
[0011]
The present invention solves the conventional problems, and includes two evaporators and two-stage compressors each having an evaporation temperature suitable for the freezer temperature and the freezer temperature of the freezer. It is an object of the present invention to provide a highly reliable, two-stage compression refrigeration system that can improve the temperature control accuracy and make the temperature of each part in the cabinet uniform, and that is more efficient, consumes less power, and is highly reliable.
[0012]
In addition, since the above-described conventional configuration needs to obtain a cooling action only by the evaporator 6, the refrigerant circulation amount diverted from the gas-liquid separator 4 is closer to the second expansion valve 5 side than the refrigerant injection passage 19 side. Will increase. Therefore, the cylinder volume of the high-stage compression element 12 of the two-stage compressor 1 is set to about 45 to 65% of the cylinder volume of the low-stage compression element 13. When this two-stage compressor 1 is applied to a refrigeration cycle having two evaporators suitable for the temperatures in the freezer compartment and the refrigerator compartment of the refrigerator-freezer, the cylinder volume of the high-stage compressor element 12 is low. Since it is considerably smaller than the cylinder volume of the stage compression element 13, there is a drawback that the refrigerating capacity of the evaporator for the refrigerating room becomes small and the freezing room and the refrigerating room may not be cooled properly.
[0013]
Another object of the present invention is to provide two evaporators and two-stage compressors each having an evaporation temperature suitable for the internal temperature of the freezer and refrigerator compartment of the refrigerator-freezer, and the cylinder volume of the high-stage compression element, By optimizing the ratio of the cylinder volume of the low-stage compression element, either the freezer compartment of the freezer / refrigerator or the refrigerator in a different temperature zone, such as the refrigerator compartment, has insufficient freezing capacity or excessive freezing capacity. It is an object of the present invention to provide a two-stage compression refrigeration apparatus that can cool each interior properly and that is highly efficient and consumes less power.
[0014]
[Means for Solving the Problems]
In order to achieve this object, the present invention includes a motor in a sealed container. A low-stage compression element and a high-stage compression element in which the piston reciprocates in the cylinder. With Reciprocating A two-stage compressor, a condenser piped to the discharge side of the high-stage compression element, an intermediate pressure expansion device piped to the outlet side of the condenser, the discharge side of the low-stage compression element and the high stage An intermediate pressure suction pipe communicating with the suction side of the compression element; an intermediate pressure evaporator connected between the intermediate pressure expansion device and the intermediate pressure suction pipe; and an outlet side of the condenser or the intermediate pressure expansion A low-pressure expansion device connected by piping to the outlet side of the device, and a low-pressure evaporator connected by piping between the low-pressure expansion device and the suction side of the low-stage compression element of the two-stage compressor, The discharge side of the low-stage compression element and the suction side of the high-stage compression element communicate with each other in the sealed container.
[0015]
Thereby, each of the two evaporators of the freezing and refrigeration apparatus can be set to an evaporation temperature suitable for the internal temperature of each of the freezing room and the freezing room, etc. The temperature of each part can be made uniform. In addition, the efficiency of the compressor is improved because the evaporation temperature of the intermediate pressure evaporator can be set high, and the efficiency of the entire refrigeration cycle is improved because the interior of each cabinet is not cooled with cold air having a temperature lower than necessary. . Furthermore, since the inside of the sealed container is at an intermediate pressure, the pressure difference between the compression chamber of each of the low-stage compression element and the high-stage compression element and the inside of the sealed container is small. The leakage amount of the refrigerant gas can be reduced, and the refrigerating capacity and efficiency of the two-stage compressor can be improved.
[0016]
Also, the present invention provides a motor and a motor in a sealed container A low-stage compression element and a high-stage compression element in which the piston reciprocates in the cylinder. With Reciprocating A two-stage compressor, a condenser piped to the discharge side of the high-stage compression element, an intermediate pressure expansion device piped to the outlet side of the condenser, the discharge side of the low-stage compression element and the high stage An intermediate pressure suction pipe communicating with the suction side of the compression element; an intermediate pressure evaporator connected between the intermediate pressure expansion device and the intermediate pressure suction pipe; and an outlet side of the condenser or the intermediate pressure expansion A low-pressure expansion device connected by piping to the outlet side of the device, and a low-pressure evaporator connected by piping between the low-pressure expansion device and the suction side of the low-stage compression element of the two-stage compressor, The suction side of the low-stage compression element is configured to communicate with the closed container.
[0017]
Thereby, each of the two evaporators of the freezing and refrigeration apparatus can be set to an evaporation temperature suitable for the internal temperature of each of the freezing room and the freezing room, etc. The temperature of each part can be made uniform. In addition, the efficiency of the compressor is improved because the evaporation temperature of the intermediate pressure evaporator can be set high, and the efficiency of the entire refrigeration cycle is improved because the interior of each cabinet is not cooled with cold air having a temperature lower than necessary. . In addition, since the inside of the sealed container is at a low pressure, each compression element and motor in the sealed container can be cooled with a low-temperature refrigerant gas returned from the low-pressure evaporator, so that the overheating of each compression element can be prevented and reliability is improved. As a result, the motor efficiency can be improved by reducing the temperature of the motor.
[0020]
In the present invention, the ratio VH / VL of the cylinder volume VL of the low-stage compression element and the cylinder volume VH of the high-stage compression element is set in the range of 0.5 to 1.3.
[0021]
Thereby, each of the two evaporators of the freezing and refrigeration apparatus can be set to an evaporation temperature suitable for the internal temperature of each of the freezing room and the freezing room, etc. The temperature of each part can be made uniform. In addition, the efficiency of the compressor is improved because the evaporation temperature of the intermediate pressure evaporator can be set high, and the efficiency of the entire refrigeration cycle is improved because the interior of each cabinet is not cooled with cold air having a temperature lower than necessary. . Furthermore, by optimizing the ratio of the cylinder volume of the high-stage compression element and the cylinder volume of the low-stage compression element, one of the refrigerators in different temperature zones such as the freezer compartment and the refrigerator compartment of the freezer / refrigerator can be refrigerating capacity. Each chamber can be appropriately cooled without being insufficient or having an excessive refrigeration capacity, and power consumption can be reduced with high efficiency. Further, by setting the ratio of the cylinder volume corresponding to each of the high pressure, low pressure, and intermediate pressure, the maximum torque and torque fluctuation of the motor can be reduced, and the motor efficiency can be improved and the vibration can be reduced.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
According to the first aspect of the present invention, a motor is provided in a sealed container. A low-stage compression element and a high-stage compression element in which the piston reciprocates in the cylinder. With Reciprocating A two-stage compressor, a condenser piped to the discharge side of the high-stage compression element, an intermediate pressure expansion device piped to the outlet side of the condenser, the discharge side of the low-stage compression element and the high stage An intermediate pressure suction pipe communicating with the suction side of the compression element; an intermediate pressure evaporator connected between the intermediate pressure expansion device and the intermediate pressure suction pipe; and an outlet side of the condenser or the intermediate pressure expansion A low-pressure expansion device connected by piping to the outlet side of the device, and a low-pressure evaporator connected by piping between the low-pressure expansion device and the suction side of the low-stage compression element of the two-stage compressor, The discharge side of the low-stage compression element and the suction side of the high-stage compression element are configured to communicate with each other in the sealed container, and the two evaporators of the refrigeration apparatus have low and intermediate pressures, respectively. Freezer and refrigerated rooms, etc. Can be respectively to the evaporator temperature suitable for each of the internal temperature, thereby is uniform temperature of the internal each part with the accuracy of temperature control in each compartment is increased. In addition, since the evaporation temperature of the intermediate pressure evaporator can be set high, the efficiency of the compressor is improved, and the efficiency of the entire refrigeration cycle is improved because each chamber is not cooled with cold air having a lower temperature than necessary. To do. Furthermore, since the discharge side of the low-stage compression element and the suction side of the high-stage compression element communicate with each other in the sealed container, the inside of the sealed container becomes an intermediate pressure, and each of the low-stage compression element and the high-stage compression element The pressure difference between the compression chamber and the airtight container is small, the amount of refrigerant gas leakage between each compression element and the airtight container can be reduced, and the refrigerating capacity and efficiency of the two-stage compressor are improved. Has the effect of being able to
[0025]
The invention according to claim 2 includes a motor and a motor in the sealed container. A low-stage compression element and a high-stage compression element in which the piston reciprocates in the cylinder. With Reciprocating A two-stage compressor, a condenser piped to the discharge side of the high-stage compression element, an intermediate pressure expansion device piped to the outlet side of the condenser, the discharge side of the low-stage compression element and the high stage An intermediate pressure suction pipe communicating with the suction side of the compression element; an intermediate pressure evaporator connected between the intermediate pressure expansion device and the intermediate pressure suction pipe; and an outlet side of the condenser or the intermediate pressure expansion A low-pressure expansion device connected by piping to the outlet side of the device, and a low-pressure evaporator connected by piping between the low-pressure expansion device and the suction side of the low-stage compression element of the two-stage compressor, The suction side of the low-stage compression element is configured so as to communicate with the inside of the closed container, and the two evaporators of the refrigeration unit have a low pressure and an intermediate pressure, respectively. Evaporator temperature suitable for each chamber temperature That can be respectively, thereby the uniformity of the temperature in the internal each part with the accuracy of temperature control in each compartment is increased. In addition, since the evaporation temperature of the intermediate pressure evaporator can be set high, the efficiency of the compressor is improved, and the efficiency of the entire refrigeration cycle is improved because each chamber is not cooled with cold air having a lower temperature than necessary. To do. Further, since the suction side of the low-stage compression element communicates with the sealed container, the pressure in the sealed container becomes low, and each compression element and motor in the sealed container is cooled with a low-temperature refrigerant gas returned from the low-pressure evaporator. Therefore, it is possible to prevent overheating of each compression element, improve reliability, and improve motor efficiency by lowering the motor temperature.
[0027]
Claim 3 The invention described in Claim 1 or claim 2 The ratio VH / VL of the cylinder volume VL of the low-stage compression element and the cylinder volume VH of the high-stage compression element is further set to the range of 0.5 to 1.3. In addition to the operation of the invention according to claim 1, claim 2, or claim 3, the refrigeration and refrigerating apparatus can be provided by adjusting the ratio of the cylinder volume of the high-stage compression element to the cylinder volume of the low-stage compression element. Either one of the refrigerators in different temperature zones such as the freezer compartment and the refrigerator compartment can be properly cooled without refrigeration capacity becoming insufficient or refrigeration capacity being excessive, and highly efficient power consumption. Has the effect of reducing. Further, by setting the ratio of the cylinder volume corresponding to each of the high pressure, low pressure, and intermediate pressure, the maximum torque and torque fluctuation of the motor can be reduced, and the motor efficiency can be improved and the vibration can be reduced.
[0029]
【Example】
Hereinafter, embodiments of the two-stage compression refrigeration apparatus according to the present invention will be described with reference to the drawings. In addition, about the same structure as the past, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.
[0030]
Example 1
1 is a refrigerant circuit diagram of a two-stage compression refrigeration refrigerator according to Embodiment 1 of the present invention. FIG. 2 shows a plan sectional view of a two-stage compressor used in the two-stage compression refrigeration apparatus of the same embodiment. FIG. 3 shows a longitudinal sectional view of a two-stage compressor used in the two-stage compression refrigeration apparatus of the same embodiment. FIG. 4 is a pressure-enthalpy diagram of the refrigeration cycle in the two-stage compression refrigeration refrigerator of the same example.
[0031]
1, 2, 3, and 4, reference numeral 20 denotes a two-stage compressor including a motor 22, a low-stage compression element 23, and a high-stage compression element 24 in a sealed container 21. 25 is a condenser connected to the discharge side of the high-stage compression element 24 by piping, and 26 is an intermediate pressure expansion device connected to the outlet side of the condenser 25 by piping. An intermediate pressure suction pipe 27 communicates with the discharge side of the low stage compression element 23 and the suction side of the high stage compression element 24, and 28 is connected between the intermediate pressure expansion device 26 and the intermediate pressure suction pipe 27. This is an intermediate pressure evaporator. 29 is a low pressure expansion device connected by piping to the outlet side of the condenser 25, and 30 is a low pressure connected by piping between the low pressure expansion device 29 and the suction side of the low stage compression element 23 of the two-stage compressor 20. Evaporator. The discharge side of the low-stage compression element 23 and the suction side of the high-stage compression element 24 are in communication with the closed container 21.
[0032]
The low-stage compression element 23 includes a cylinder 31, a piston 32, a connecting rod 33, a suction muffler 34, a discharge muffler 35, and the like, and the high-stage compression element 24 similarly includes a cylinder 36, a piston 37, a connecting rod 38, a suction muffler 39, and a discharge muffler. 40 mag. The motor 22 includes a rotor 42 and a stator 43 fixed to the crankshaft 41. The crankshaft 41 has an eccentric part 41a, and the eccentric part 41a and the pistons 32 and 37 are connected by connecting rods 33 and 38, respectively. Reference numeral 42 denotes a low-pressure suction pipe that is fixed to the sealed container 21 and communicates the suction muffler 34 and the low-pressure evaporator 30. Reference numeral 43 denotes a discharge pipe fixed to the sealed container 21, one end communicating with the discharge muffler 40 via the discharge pipe 44, and the other end communicating with the condenser 25 via the pipe. 45 is a lubricating oil which is stored in the lower part of the sealed container 21.
[0033]
The operation of the hermetic compressor configured as described above will be described below.
[0034]
When the crankshaft 41 is rotated by the motor 22, the pistons 32 and 37 are reciprocated in the cylinders 31 and 36 by the connecting rods 33 and 38, respectively. The low-stage compression element 23 sucks the refrigerant gas from the low-pressure evaporator 30 into the cylinder 31 through the low-pressure suction pipe 42 and the suction muffler 34, and then compresses the refrigerant gas to an intermediate pressure and passes through the discharge muffler 35. Discharge into the sealed container 21. The refrigerant gas discharged from the discharge muffler 35 is mixed with the refrigerant gas flowing into the sealed container 21 from the intermediate pressure suction pipe 27, sucked into the cylinder 36 from the suction muffler 39 of the high-stage compression element 24, and compressed again. Is done. The refrigerant gas compressed by the high-stage compression element 24 is sent to the condenser 25 through the discharge muffler 40, the discharge pipe 44, and the discharge pipe 43. In the condenser 25, the refrigerant gas dissipates heat and is condensed into a liquid refrigerant, and then is divided into two flow paths. One of them flows into the intermediate pressure expansion device 26 to be depressurized, and flows into the intermediate pressure evaporator 28 to evaporate. At this time, the intermediate pressure evaporator 28 exhibits a cooling action by removing heat from the surroundings. The refrigerant gas exiting the intermediate pressure evaporator 28 returns to the two-stage compressor 1 through the intermediate pressure suction pipe 27.
[0035]
The other liquid refrigerant from the condenser 25 flows into the low-pressure expansion device 29 and is depressurized, and flows into the low-pressure evaporator 30 and evaporates. At this time, by taking heat away from the surroundings, the low-pressure evaporator 28 exhibits a cooling action. The refrigerant gas exiting the low-pressure evaporator 30 returns to the two-stage compressor 1 through the low-pressure suction pipe 42 and is again sucked into the low-stage compression element 23.
[0036]
Further, the lubricating oil 45 is sucked up by the centrifugal force from the lower end portion of the crankshaft 41, and after lubricating each sliding portion of the crankshaft 41, the lubricating oil 45 is scattered by the centrifugal force from the upper end portion of the eccentric portion 41a, and the pistons 32, 37. And the sliding portions of the cylinders 31 and 36 and the sliding portions of the connecting rods 33 and 38 are lubricated.
[0037]
In the refrigeration cycle of the present embodiment, as shown in FIG. 4, the refrigerant in the intermediate pressure evaporator 28 has an intermediate pressure, and the refrigerant in the low pressure evaporator 30 has a low pressure. When this refrigeration cycle is applied to a refrigeration apparatus, the intermediate pressure evaporator 28 is used for refrigeration, and the low pressure evaporator 30 is used for refrigeration. Therefore, it is possible to make the evaporator temperatures suitable for the internal temperatures of the freezer compartment and the refrigerator compartment, respectively. For example, when the temperature of the refrigerator compartment is set to 3 ° C to 7 ° C and the temperature of the freezer compartment is set to -18 ° C to -22 ° C, the evaporation temperature of the intermediate pressure evaporator 28 is set to about 0 ° C to -10 ° C. The evaporation temperature of the low-pressure evaporator 30 can be set to about −25 ° C. to −35 ° C., and since the difference between the temperature in each chamber and the evaporation temperature is small, the accuracy of temperature control in each chamber increases. The temperature of each part in the refrigerator can be made uniform. In particular, since the evaporation temperature of the intermediate pressure evaporator 28 can be set high, the efficiency of the two-stage compressor 20 is improved, and each chamber is not cooled with cold air having a temperature lower than necessary. Increases efficiency.
[0038]
Furthermore, since the discharge side of the low-stage compression element 23 and the suction side of the high-stage compression element 24 communicate with the inside of the sealed container 20, the inside of the sealed container 20 becomes an intermediate pressure, and the low-stage compression element 23 and the high-stage compression element 23 The pressure difference between the respective cylinders 31 and 36 of the compression element 24 and the inside of the sealed container 21 is small, and the leakage amount of the refrigerant gas between each compression element and the inside of the sealed container 21 can be reduced. The refrigeration capacity and efficiency of the machine 20 can be improved.
[0039]
As described above, the two-stage compression refrigeration apparatus of the present embodiment includes the two-stage compressor 20 including the motor 22, the low-stage compression element 23, and the high-stage compression element 24 in the sealed container 21, and the high-stage compression element. The condenser 25 connected to the discharge side of 24, the intermediate pressure expansion device 26 connected to the outlet side of the condenser 25, and the discharge side of the low-stage compression element 23 and the suction side of the high-stage compression element 24 communicate with each other. Intermediate pressure suction pipe 27, intermediate pressure evaporator 28 connected between intermediate pressure expansion device 26 and intermediate pressure suction pipe 27, outlet side of condenser 25 or outlet side of intermediate pressure expansion device 26 and piping The low-pressure expansion device 29 is connected to the low-pressure evaporator 30 connected between the low-pressure expansion device 29 and the suction side of the low-stage compression element 23 of the two-stage compressor 20. 23 discharge side and high stage compression required 24 is connected to the closed container 21 so that the accuracy of temperature control in each warehouse can be improved, the temperature of each part in the warehouse can be made uniform, and more efficient and less power consumption. A two-stage compression refrigeration apparatus can be provided.
[0040]
(Example 2)
FIG. 5 shows a refrigerant circuit diagram of a two-stage compression refrigeration refrigerator according to Embodiment 2 of the present invention. FIG. 6 shows a plan sectional view of a two-stage compressor used in the two-stage compression refrigeration apparatus of the same embodiment.
[0041]
The following description will be made with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. 5 and 6, 46 is a two-stage compressor including a low-stage compression element 47 and a high-stage compression element 48. An intermediate pressure suction pipe 49 communicates with the discharge side of the low-stage compression element 47 and the suction side of the high-stage compression element 48. Reference numeral 50 denotes a low-pressure suction pipe fixed to the sealed container 21, which communicates the low-pressure evaporator 30 and the sealed container 21. Further, the suction side of the low-stage compression element 47 communicates from the suction muffler 51 into the sealed container 21. Reference numeral 52 denotes a suction muffler of the high-stage compression element 48, which communicates with the intermediate pressure suction pipe 49. A communication pipe 53 communicates the discharge muffler 54 and the suction muffler 52.
[0042]
The operation of the two-stage compression refrigeration apparatus configured as described above will be described below.
[0043]
Since the second embodiment is the same as the first embodiment except for the internal configuration of the two-stage compressor 46, the effect of the present refrigeration cycle can be obtained in substantially the same manner as the first embodiment. That is, it is possible to increase the accuracy of the temperature control in each cabinet and make the temperature of each part in the cabinet uniform, further reducing power consumption with high efficiency.
[0044]
In the present embodiment, since the suction side of the low-stage compression element 47 communicates with the sealed container 21, the sealed container 21 becomes a low pressure, and the sealed container is filled with the low-temperature refrigerant gas returned from the low-pressure evaporator 30. 21 can cool the low-stage compression element 47, the high-stage compression element 48, and the motor 22, so that the overheating of the compression elements 47 and 48 can be prevented and the reliability is improved, and the motor efficiency is improved by the temperature drop of the motor 22. can do.
[0045]
As described above, the two-stage compression refrigeration apparatus of the present embodiment includes the two-stage compressor 46 including the motor 22, the low-stage compression element 47, and the high-stage compression element 48 in the sealed container 21, and the high-stage compression element. The condenser 28 connected to the discharge side of 48, the intermediate pressure expansion device 26 connected to the outlet side of the condenser 28, and the discharge side of the low-stage compression element 47 and the suction side of the high-stage compression element 48 communicate with each other. Intermediate pressure suction pipe 49, intermediate pressure evaporator 28 connected between intermediate pressure expansion device 26 and intermediate pressure suction pipe 49, outlet side of condenser 25 or outlet side of intermediate pressure expansion device 26 and piping The low-pressure expansion device 29 is connected to the low-pressure evaporator 30 connected between the low-pressure expansion device 29 and the suction side of the low-stage compression element 47 of the two-stage compressor 46. 47 suction side is sealed container 2 Because it is configured to communicate with each other, it is possible to improve the temperature control accuracy in each chamber and to equalize the temperature of each section in the chamber, to further reduce power consumption with high efficiency and to further reduce the two-stage compression The reliability of the machine 46 can be improved and the motor efficiency can be improved.
[0046]
Example 3
FIG. 7 shows a refrigerant circuit diagram of a two-stage compression refrigeration refrigerator according to Embodiment 3 of the present invention. FIG. 8 shows a plan sectional view of a two-stage compressor used in the two-stage compression refrigeration apparatus of the same embodiment.
[0047]
The following description will be made with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. 8 and 9, 55 is a two-stage compressor including a low-stage compression element 56 and a high-stage compression element 57. An intermediate pressure suction pipe 58 communicates with the discharge side of the low-stage compression element 56 and the suction side of the high-stage compression element 57. Reference numeral 59 denotes a suction muffler of the high-stage compression element 57, which communicates with the intermediate pressure suction pipe 58. A communication pipe 60 communicates the discharge muffler 61 and the suction muffler 59. Reference numeral 62 denotes a discharge pipe fixed to the sealed container 21, one end communicating with the sealed container 21 and the other end communicating with the condenser 25 via a pipe. The discharge side of the high-stage compression element 57 communicates with the inside of the sealed container 21 from the discharge muffler 63.
[0048]
The operation of the two-stage compression refrigeration apparatus configured as described above will be described below.
[0049]
Since the second embodiment is the same as the first embodiment except for the internal configuration of the two-stage compressor 55, the effect of the present refrigeration cycle can be obtained in substantially the same manner as the first embodiment. That is, it is possible to increase the accuracy of the temperature control in each cabinet and make the temperature of each part in the cabinet uniform, further reducing power consumption with high efficiency.
[0050]
In this embodiment, since the discharge side of the high-stage compression element 57 communicates with the sealed container 21, the inside of the sealed container 21 becomes high pressure, and the pressure in the sealed container 21 is higher than the pressure in the cylinders 31 and 36. Become. Therefore, the lubricating oil 45 scattered from the eccentric portion 41a of the crankshaft 41 to the cylinders 31 and 36 flows into the gaps between the cylinders 31 and 36 and the pistons 32 and 37 due to the pressure difference, and the pistons 32 and 37 and the cylinders The lubricity of sliding parts such as 31 and 36 can be improved and the reliability can be improved.
[0051]
As described above, the two-stage compression refrigeration apparatus of the present embodiment includes the two-stage compressor 55 including the motor 22, the low-stage compression element 56, and the high-stage compression element 57 in the sealed container 21, and the high-stage compression element. The condenser 25 connected to the discharge side of 57, the intermediate pressure expansion device 26 connected to the outlet side of the condenser 25, and the discharge side of the low-stage compression element 56 and the suction side of the high-stage compression element 57 communicate with each other. Intermediate pressure suction pipe 58, intermediate pressure evaporator 28 connected between intermediate pressure expansion device 26 and intermediate pressure suction pipe 58, outlet side of condenser 25 or outlet side of intermediate pressure expansion device 26 and piping A low-pressure expansion device 29 connected to the low-pressure evaporator 30 connected between the low-pressure expansion device 29 and the suction side of the low-stage compression element 56 of the two-stage compressor 55. 57 discharge side is sealed container 2 Because it is configured to communicate with each other, it is possible to improve the temperature control accuracy in each warehouse and to equalize the temperature of each part in the warehouse, to further reduce the power consumption with high efficiency, and due to the pressure difference Lubricating oil 45 can be sufficiently supplied from the sealed container 21 into the cylinders 31 and 36 of the low-stage compression element 56 and the high-stage compression element 57, and the sliding parts such as the pistons 32 and 37 and the cylinders 31 and 36. Lubricity can be improved and reliability can be improved.
[0052]
Example 4
FIG. 9: shows the longitudinal cross-sectional view of the two-stage compressor used for the two-stage compression refrigerating / refrigeration apparatus by Example 4 of this invention.
[0053]
The following description will be made with reference to the drawings. The same components as those in the first embodiment, the second embodiment, or the third embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 9, 64 is a two-stage compressor including a low-stage compression element 65 and a high-stage compression element 66. The low-stage compression element 65 includes a cylinder 66, a piston 67, a connecting rod 68, a suction muffler 34, a discharge muffler 35, and the like, and the high-stage compression element 66 similarly includes a cylinder 69, a piston 70, a connecting rod 71, a suction muffler 39, and a discharge muffler. 40 mag. The ratio VH / VL between the cylinder volume VL of the low-stage compression element 65 and the cylinder volume VH of the high-stage compression element 66 is set in the range of 0.5 to 1.3.
[0054]
The operation of the two-stage compression refrigeration apparatus configured as described above will be described below.
[0055]
Except for the cylinder volume ratio VH / VL of the two-stage compressor 64, the effect of this refrigeration cycle is almost the same as in the first, second, or third embodiment because it is the same as that in the first, second, or third embodiment. Is obtained. That is, it is possible to increase the accuracy of temperature control in each cabinet and to equalize the temperature of each part in the cabinet, to further increase the efficiency and to reduce power consumption and to improve the reliability.
[0056]
In this embodiment, the ratio VH / VL of the cylinder volume VL of the low-stage compression element 65 and the cylinder volume VH of the high-stage compression element 69 is set in the range of 0.5 to 1.3, and the effect is as follows. explain.
[0057]
Generally, in the refrigerator-freezer, the ratio of the refrigerator compartment volume to the freezer compartment volume is about 1.5 to 4.0, and the refrigerator compartment is larger, but the refrigerator compartment should be cooler. Therefore, the required refrigeration capacity is smaller than this ratio. Therefore, the ratio of the required freezing capacity of the refrigerator compartment to the required freezing capacity of the freezer room is about 0.5 to 1.1.
[0058]
For example, when the temperature of the refrigerator compartment including the partial chamber is set to −5 ° C. to 7 ° C. and the temperature of the freezer compartment is set to −22 ° C. to −18 ° C., the evaporation temperature of the intermediate pressure evaporator 28 is set to −20. The evaporation temperature of the low-pressure evaporator 30 is set to about −35 ° C. to −25 ° C. to about 0 ° C. to 0 ° C. When the ratio of the refrigerating capacity between the freezer compartment and the refrigerator compartment is set to the above-described 0.5 to 1.1 at these evaporation temperatures, according to the inventors' investigation, the cylinder of the low-stage compression element 65 It is known from calculations and experiments that the ratio VH / VL between the volume VL and the cylinder volume VH of the high-stage compression element 69 may be 0.5 to 1.3.
[0059]
If the value of VH / VL is too small, the amount of refrigerant circulating on the high-stage compression side decreases, the refrigerating capacity of the intermediate pressure evaporator 28 decreases, and adverse effects such as an increase in the temperature in the refrigerator compartment appear. On the other hand, if the value of VH / VL is too large, the refrigerant circulation amount on the low-stage compression side decreases, the refrigeration capacity of the low-pressure evaporator 30 decreases, and adverse effects such as an increase in the internal temperature of the freezer compartment occur. appear.
[0060]
Accordingly, by making the ratio of the cylinder volume of the high-stage compression element 66 and the cylinder volume of the low-stage compression element 64 appropriate, either one of the insides of different temperature zones such as the freezer compartment and the refrigerating compartment of the refrigerating / refrigeration apparatus is provided. Each chamber can be properly cooled without causing the refrigeration capacity to become insufficient or the refrigeration capacity to be excessive, and the power consumption can be reduced with high efficiency.
[0061]
Further, during the operation of the compressor, when the differential pressure between the high pressure and the intermediate pressure is larger than the differential pressure between the intermediate pressure and the low pressure, the cylinder volume of the high stage compression element 66 is made smaller than the cylinder volume of the low stage compression element 64. The difference between the torque required for compression of the high-stage compression element 66 and the torque required for compression of the low-stage compression element 64 is reduced, the maximum torque and torque fluctuation of the motor 22 can be reduced, and the motor efficiency is improved. Vibration can be reduced. In this case, each cylinder volume is adjusted by changing the outer diameters of the pistons 67 and 70. Conversely, when the differential pressure between the high pressure and the intermediate pressure is smaller than the differential pressure between the intermediate pressure and the low pressure, the same effect can be obtained by making the cylinder volume of the high stage compression element 66 larger than the cylinder volume of the low stage compression element 64. Is obtained.
[0062]
As described above, in the two-stage compression refrigeration apparatus of the present embodiment, the ratio VH / VL of the cylinder volume VL of the low-stage compression element 65 and the cylinder volume VH of the high-stage compression element 66 is in the range of 0.5 to 1.3. Therefore, in addition to the effects of the first embodiment, the second embodiment, or the third embodiment, either one of the refrigerators in the different temperature zones such as the freezer compartment and the refrigerator compartment of the freezer / refrigerator is Each chamber can be properly cooled without causing the refrigeration capacity to become insufficient or the refrigeration capacity to be excessive, and the power consumption can be reduced with high efficiency. Further, by setting the ratio of the cylinder volume corresponding to each of the high pressure, low pressure, and intermediate pressure, the maximum torque and torque fluctuation of the motor 22 can be reduced, and the motor efficiency can be improved and the vibration can be reduced.
[0063]
(Example 5)
FIG. 10 is a plan sectional view of a two-stage compressor used in a two-stage compression refrigeration refrigerator according to Embodiment 5 of the present invention.
[0064]
The following description will be made with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 10, 72 is a two-stage compressor including a low-stage compression element 23 and a high-stage compression element 73. Reference numeral 74 denotes an intermediate pressure suction pipe that communicates with the discharge side of the low-stage compression element 23 and the suction side of the high-stage compression element 73. Reference numeral 75 denotes a suction muffler for the high-stage compression element 73. An opening of the intermediate pressure suction pipe 74 into the sealed container 21 communicates with the suction muffler 75 of the high-stage compression element 73 through a slight gap.
[0065]
The operation of the two-stage compression refrigeration apparatus configured as described above will be described below.
[0066]
Since the second embodiment is the same as the first embodiment except for the internal configuration of the two-stage compressor 46, the effect of the present refrigeration cycle can be obtained in substantially the same manner as the first embodiment. That is, it is possible to increase the accuracy of the temperature control in each cabinet and make the temperature of each part in the cabinet uniform, further reducing power consumption with high efficiency.
[0067]
In the present embodiment, the opening portion of the intermediate pressure suction pipe 74 into the sealed container 21 communicates with the suction muffler 75 of the high-stage compression element 73 through a slight gap. The refrigerant gas that has returned to the sealed container 21 through the pressure suction pipe 74 is sucked into the suction muffler 75 on the suction side of the high-stage compression element 73 through a slight gap. Therefore, the refrigerant gas is less affected by heat received from the low-stage compression element 23, the high-stage compression element 73, and the motor 22, and the temperature rise is suppressed to a small level. Therefore, the density of the refrigerant gas to be sucked increases, the refrigerant circulation amount increases, and the efficiency can be improved.
[0068]
Furthermore, compared with the case where the suction pipe 74 for intermediate pressure and the suction side of the high-stage compression element 73 are directly connected, the pressure pulsation from the high-stage compression element 73 is diffused into the sealed container 21 because there is a slight gap. It is difficult to be transmitted to the intermediate pressure suction pipe 74 and noise can be prevented.
[0069]
As described above, in the two-stage compression refrigeration apparatus of the present embodiment, the opening of the intermediate pressure suction pipe 74 into the sealed container 21 communicates with the suction side of the high-stage compression element 73 via a slight gap. Therefore, in addition to the effects of the first embodiment, the refrigerant gas returned from the intermediate pressure evaporator 28 through the intermediate pressure suction pipe 74 and into the sealed container 21 is compressed in a high stage through a slight gap. Since the air is sucked into the suction side of the element 73, the influence of heat received from each compression element and the motor 22 is small, and the temperature rise is suppressed to a small level. Therefore, the density of the refrigerant gas to be sucked increases, the refrigerant circulation amount increases, and the efficiency can be improved. Furthermore, the pressure pulsation from the high-stage compression element diffuses into the sealed container and is difficult to be transmitted to the intermediate pressure suction pipe, thereby preventing the generation of noise.
[0070]
【The invention's effect】
As described above, the invention according to claim 1 includes a motor in the sealed container. A low-stage compression element and a high-stage compression element in which the piston reciprocates in the cylinder. With Reciprocating A two-stage compressor, a condenser piped to the discharge side of the high-stage compression element, an intermediate pressure expansion device piped to the outlet side of the condenser, the discharge side of the low-stage compression element and the high stage An intermediate pressure suction pipe communicating with the suction side of the compression element; an intermediate pressure evaporator connected between the intermediate pressure expansion device and the intermediate pressure suction pipe; and an outlet side of the condenser or an intermediate pressure expansion device A low-pressure expansion device connected by piping to the outlet side of the low-pressure evaporator, and a low-pressure evaporator connected by piping between the low-pressure expansion device and the suction side of the low-stage compression element of the two-stage compressor, Since the discharge side of the low-stage compression element and the suction side of the high-stage compression element are in communication with each other in the hermetic container, the two evaporators of the refrigeration apparatus are each a freezer compartment and a refrigerator compartment. Evaporation temperature suitable for the internal temperature Can, thereby the uniformity of the temperature in the internal each part with the accuracy of temperature control in each compartment is increased. In addition, the efficiency of the compressor is improved because the evaporation temperature of the intermediate pressure evaporator can be set high, and the efficiency of the entire refrigeration cycle is improved because the interior of each cabinet is not cooled with cold air having a temperature lower than necessary. . Furthermore, since the inside of the sealed container is at an intermediate pressure, the pressure difference between the compression chamber of each of the low-stage compression element and the high-stage compression element and the inside of the sealed container is small. The leakage amount of the refrigerant gas can be reduced, and the refrigerating capacity and efficiency of the two-stage compressor can be improved.
[0071]
Moreover, the invention according to claim 2 includes a motor and a motor in the sealed container. A low-stage compression element and a high-stage compression element in which the piston reciprocates in the cylinder. With Reciprocating A two-stage compressor, a condenser piped to the discharge side of the high-stage compression element, an intermediate pressure expansion device piped to the outlet side of the condenser, the discharge side of the low-stage compression element and the high stage An intermediate pressure suction pipe communicating with the suction side of the compression element; an intermediate pressure evaporator connected between the intermediate pressure expansion device and the intermediate pressure suction pipe; and an outlet side of the condenser or the intermediate pressure expansion A low-pressure expansion device connected by piping to the outlet side of the device, and a low-pressure evaporator connected by piping between the low-pressure expansion device and the suction side of the low-stage compression element of the two-stage compressor, Since the suction side of the low-stage compression element is configured to communicate with the sealed container, the two evaporators of the refrigeration unit have a low pressure and an intermediate pressure, respectively. Evaporation suitable for each chamber temperature Can be respectively to the temperature, thereby is uniform temperature of the internal each part with the accuracy of temperature control in each compartment is increased. In addition, since the evaporation temperature of the intermediate pressure evaporator can be set high, the efficiency of the compressor is improved, and the efficiency of the entire refrigeration cycle is improved because each chamber is not cooled with cold air having a lower temperature than necessary. To do. Further, since the suction side of the low-stage compression element communicates with the sealed container, the pressure in the sealed container becomes low, and each compression element and motor in the sealed container is cooled with a low-temperature refrigerant gas returned from the low-pressure evaporator. Therefore, it is possible to prevent overheating of each compression element, improve reliability, and improve motor efficiency by lowering the temperature of the motor.
[0073]
Claims 3 The invention described in Claim 1 or claim 2 The ratio VH / VL of the cylinder volume VL of the low stage compression element and the cylinder volume VH of the high stage compression element is set in the range of 0.5 to 1.3 in addition to the invention described in 1. In addition, one of the refrigerators in the different temperature zones such as the freezer compartment and the refrigerator compartment of the freezer / refrigerator can be properly cooled without causing the freezing capacity to be insufficient or the freezing capacity to be excessive, and High efficiency and low power consumption. Further, by setting the ratio of the cylinder volume corresponding to each of the high pressure, low pressure, and intermediate pressure, the maximum torque and torque fluctuation of the motor can be reduced, and the motor efficiency can be improved and the vibration can be reduced.
[Brief description of the drawings]
FIG. 1 is a refrigerant circuit diagram of a first embodiment of a two-stage compression refrigeration refrigerator according to the present invention.
FIG. 2 is a plan sectional view of a two-stage compressor used in the two-stage compression refrigeration apparatus of the same embodiment.
FIG. 3 is a longitudinal sectional view of a two-stage compressor used in the two-stage compression refrigeration apparatus of the same embodiment.
FIG. 4 is a pressure-enthalpy diagram of a refrigeration cycle in the two-stage compression refrigeration apparatus of the same example.
FIG. 5 is a refrigerant circuit diagram of a second embodiment of a two-stage compression refrigeration refrigerator according to the present invention.
FIG. 6 is a plan sectional view of a two-stage compressor used in the two-stage compression refrigeration apparatus of the same embodiment.
FIG. 7 is a refrigerant circuit diagram of Embodiment 3 of a two-stage compression refrigeration apparatus according to the present invention.
FIG. 8 is a plan sectional view of a two-stage compressor used in the two-stage compression refrigeration apparatus of the same embodiment.
FIG. 9 is a longitudinal sectional view of a two-stage compressor in Embodiment 4 of a two-stage compression refrigeration apparatus according to the present invention.
FIG. 10 is a plan sectional view of a two-stage compressor in Embodiment 5 of a two-stage compression refrigeration apparatus according to the present invention.
FIG. 11 is a piping system diagram of a two-stage compression refrigeration cycle using a conventional two-stage compressor.
[Explanation of symbols]
20 Two-stage compressor
21 Airtight container
22 Motor
23 Low-stage compression element
24 High compression elements
25 Condenser
26 Intermediate pressure expansion device
27 Suction pipe for intermediate pressure
28 Evaporator for intermediate pressure
29 Low pressure expansion device
30 Low pressure evaporator
46 Two-stage compressor
47 Low stage compression element
48 High compression element
49 Suction pipe for intermediate pressure
55 Two-stage compressor
56 Low stage compression element
57 High-stage compression element
58 Intermediate pressure suction pipe
64 Two-stage compressor
65 Low stage compression element
66 High-stage compression element
72 Two-stage compressor
73 High compression element
74 Suction pipe for intermediate pressure

Claims

A reciprocating two-stage compressor having a motor, a low-stage compression element and a high-stage compression element in which a piston reciprocates in the cylinder, and a condensing pipe connected to the discharge side of the high-stage compression element. An intermediate pressure expansion device connected by piping to the outlet side of the condenser, an intermediate pressure suction pipe communicating with the discharge side of the low-stage compression element and the suction side of the high-stage compression element, and the intermediate pressure expansion device And an intermediate pressure evaporator connected between the suction pipe for intermediate pressure, a low pressure expansion device connected by piping to the outlet side of the condenser or the outlet side of the intermediate pressure expansion device, and the low pressure expansion device And a low-pressure evaporator connected between the suction side of the low-stage compression element of the two-stage compressor, and the discharge side of the low-stage compression element and the suction side of the high-stage compression element are Two stages communicating in a sealed container Shrinkage refrigeration refrigeration equipment.

A reciprocating two-stage compressor having a motor, a low-stage compression element and a high-stage compression element in which a piston reciprocates in the cylinder, and a condensing pipe connected to the discharge side of the high-stage compression element. An intermediate pressure expansion device connected by piping to the outlet side of the condenser, an intermediate pressure suction pipe communicating with the discharge side of the low-stage compression element and the suction side of the high-stage compression element, and the intermediate pressure expansion device and the intermediate-pressure and intermediate-pressure evaporator connected by piping between the suction pipe, the condenser outlet side or the intermediate-pressure expansion outlet side of the apparatus and the low-pressure expansion device connected by piping, the low pressure expansion device And a low-pressure evaporator connected between the suction side of the low-stage compression element of the two-stage compressor and the suction side of the low-stage compression element communicated with the inside of the sealed container. apparatus.

The two-stage compression refrigeration according to claim 1 or 2 , wherein a ratio VH / VL of a cylinder volume VL of the low-stage compression element and a cylinder volume VH of the high-stage compression element is set in a range of 0.5 to 1.3. Refrigerator.