JP3874980B2

JP3874980B2 - Air conditioner

Info

Publication number: JP3874980B2
Application number: JP2000014588A
Authority: JP
Inventors: 慎一若本; 寿守務吉村; 智彦河西
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2000-01-24
Filing date: 2000-01-24
Publication date: 2007-01-31
Anticipated expiration: 2020-01-24
Also published as: JP2001201191A

Description

【０００１】
【発明の属する技術分野】
本発明は、空気調和装置に関する。さらに詳しくは住宅やビル空調に用いられる空調機または冷凍冷蔵される食品生産加工に用いられる冷凍装置などに適用される空気調和装置に関する。
【０００２】
【従来の技術】
図１１には、第１の従来の空気調和装置９１（従来例１）が示されている。図１１に示される従来の空気調和装置９１は、圧縮機２、凝縮器３、減圧装置４、蒸発器５を主要構成機器として備え、圧縮機２から凝縮器３に至る冷媒配管６に圧縮機２から吐出された冷媒蒸気中の冷凍機油を分離する油分離器１０と、一方を油分離器１０に接続し他方を蒸発器５から圧縮機２に至る冷媒配管６に接続した返油回路１１と、その返油回路１１に異物を捕捉するためのフィルター１２と、返油回路１１を流れる冷凍機油の流量を制御する油流量制御手段、たとえば毛細管１３を備えている。
【０００３】
つぎに図１１の空気調和装置９１の動作について説明する。圧縮機２から吐出される高温高圧の冷媒蒸気と冷凍機油は油分離器１０に流入し、冷凍機油が分離され、冷媒蒸気のみが凝縮器３に流入し、空気などと熱交換して凝縮し、高温高圧の冷媒液になる。さらに、減圧装置４で低温低圧の気液二相状態まで減圧され、蒸発器５に流入する。低圧の気液二相冷媒は蒸発器５で空気などと熱交換して蒸発し、圧縮機２に戻される。
【０００４】
一方、油分離器１０で分離された冷凍機油は返油回路１１を通りフィルター１２で異物が除去され、そののち、冷媒蒸気とともに圧縮機２に戻される。
【０００５】
以上のように第１の従来の空気調和装置においては、圧縮機２や冷媒配管６に残留する水分、空気、構成機器を加工する際に混入する加工油や洗浄剤によって冷凍機油や冷凍機油に混ぜている添加剤が劣化し、これらの劣化物が空気調和装置９１の主要構成機器や冷媒配管に付着する。しかし、最近まで作動媒体として用いていたハイドロクロロフルオロカーボン系の冷媒は塩素原子をもつため前記劣化物の大部分を溶解し、主要構成機器を構成する配管や冷媒配管の詰まりを生じることは少なかった。
【０００６】
しかし、環境保全の観点から塩素原子を含まないハイドロフルオロカーボン系の冷媒への転換が急速に進み、主要構成機器や冷媒配管内を劣化物が溶けることなく循環するため、冷媒配管などに劣化物が付着し詰まりを生じるおそれがある。そのため、従来の空気調和装置では返油回路に設置したフィルターを用いて、冷媒液とともに冷媒配管を流れる前記冷凍機油や添加剤の劣化物を捕捉し、配管詰まりを防止している。
【０００７】
また、図１２には第２の従来の空気調和装置９２（従来例２）が示されている。図１２において、４１はフィルター１２の上流に設け冷媒液と冷凍機油を混合する混合器、４２は一方を油分離器１０と凝縮器３に至る冷媒配管６に接続し他方を混合器４１に接続した冷媒液配管、４３は油分離器１０から供給される冷媒蒸気を凝縮させる熱交換器、４４は冷媒液配管４２を流れる冷媒液の流量を制御する第３の毛細管である。その他の構成については従来例１と同様につき説明を省略する。
【０００８】
つぎに図１２の空気調和装置９２の動作について説明する。油分離器１０から凝縮器３に供給される冷媒蒸気の一部は熱交換器４３で凝縮し、第３の毛細管４４を通り混合器４１に送られる。一方、油分離器１０で分離された冷凍機油は毛細管１３を通り混合器４１に送られ冷媒液と混合して、冷凍機油中に溶けている冷凍機油の劣化物や添加剤の劣化物が析出する。析出した劣化物と酸化スケールなどの異物はフィルター１２で捕捉され、冷凍機油と冷媒のみが冷媒配管６を通り圧縮機２に戻される。その他の動作については従来例１と同様につき説明を省略する。
【０００９】
以上のような第２の従来の空気調和装置９２においては、返油回路１１を流れる冷凍機油に冷媒液配管から供給される冷媒を注入することによって冷凍機油中に溶けている冷凍機油の劣化物や添加剤の劣化物を析出させ、酸化スケールや冷凍機油に溶けない劣化物とともに冷凍機油に溶ける劣化物をフィルター１２で捕捉して、酸化スケールや劣化物による配管詰まりを防止している。
【００１０】
【発明が解決しようとする課題】
冷凍機油や添加物は、空気調和装置の運転前には冷媒または冷凍機油に溶解しているが、空気調和装置の運転とともに次第に劣化し、
▲１▼空気調和装置の主要構成機器や冷媒配管におけるすべての箇所で冷媒や冷凍機油にとけるもの、
▲２▼冷凍機油には溶けるが冷媒液には溶けないもの、または冷媒の温度低下などにより溶解度が低下して析出するもの、
▲３▼冷媒配管や主要構成機器内のすべてにおいて、冷凍機油や冷媒液にまったく溶けないもの
に変化する。これらの劣化物のうち、▲２▼や▲３▼まで劣化が進んだ劣化物は冷媒が冷媒配管や主要構成機器内を流れる際の圧力損失の増加や配管詰まりなどを引き起こす。劣化物の粒径について、本発明者らは壁面に付着している異物を電子顕微鏡で観察し、数μｍ〜数百μｍの範囲に分布していることを確認している。
【００１１】
以上から、図１１に示される従来例１の空気調和装置９１では、
１）粒径が数μｍから数百μｍの広い範囲に分布している劣化物を捕捉するために、フィルターの透過粒径を小さくすると目詰まりを生じる。
２）フィルターの目詰まりを生じた場合に冷凍機油が圧縮機に供給されなくなり、圧縮機の軸の焼きつきを生じる。
３）冷凍機油に溶けている劣化物▲２▼を捕獲できないため、ハイドロフルオロカーボン系の冷媒を利用する空気調和装置では、凝縮器、蒸発器、減圧装置や冷媒配管などに劣化物▲２▼が付着して冷媒が循環する際の圧力損失が増加し必要な能力を得られなくなったり、冷媒が循環しなくなる
などの問題がある。
【００１２】
また、図１２に示される従来例２の空気調和装置９２では、
１）粒径が数μｍから数百μｍの広い範囲に分布している劣化物を捕捉するために、フィルターの透過粒径を小さくすると目詰まりを生じる。
２）フィルターの目詰まりを生じた場合に冷凍機油が圧縮機に供給されなくなる。
３）さらに、後段の本発明の実施の形態２で述べるが、冷媒液と油との混合比によっては冷媒液を冷凍機油に注入しても劣化物▲２▼が析出しないため、フィルターで捕捉できない。したがって、ハイドロフルオロカーボン系の冷媒を利用する空気調和装置では、凝縮器、蒸発器、減圧装置や冷媒配管などに劣化物▲２▼が付着して冷媒が循環する際の圧力損失が増加したり、冷媒が循環しなくなる
などの問題がある。
【００１３】
本発明はかかる問題を解消するためになされたものであり、異物捕捉手段に目詰まりが生じた場合でも冷凍機油を圧縮器に供給することができる空気調和装置を供給することを目的とする。
【００１４】
【課題を解決するための手段】
請求項１および２記載の発明にかかわる空気調和装置は、いずれも圧縮機、凝縮器、減圧装置、および蒸発器が順次冷媒配管で接続され、
さらに前記圧縮機から凝縮器に至る冷媒配管に当該圧縮機から吐出された冷媒蒸気中の冷凍機油を分離する油分離器、一方を前記油分離器に接続し他方を前記蒸発器から圧縮機に至る冷媒配管に接続した返油回路、および該返油回路に冷凍機油の流量を制御する第１の油流量制御手段を備えた空気調和装置であって、
前記返油回路には、異物を捕捉できる異物捕捉手段および該異物捕捉手段をバイパスさせるバイパス手段が設けられており、
前記バイパス手段には、前記異物捕捉手段の出入口の圧力差に応じて前記バイパス手段を流れる冷凍機油の流量を制御する第２の油流量制御手段が設けられており、
請求項１にかかわる発明では前記第２の油流量制御手段は毛細管であり、請求項２にかかわる発明では前記第２の油流量制御手段は電子式膨張弁である。
【００１５】
請求項３記載の発明にかかわる空気調和装置は、前記異物捕捉手段が、フィルタからなるものである。
【００１６】
請求項４記載の発明にかかわる空気調和装置は、前記フィルタが、焼結金属、セルロース、多孔性陶磁器、ろ紙、多孔質高分子材料、金属網および繊維織布のうちの少なくとも１種の材料から作製されてなるものである。
【００１７】
請求項５記載の発明にかかわる空気調和装置は、前記冷媒配管を流れる冷媒の一部を前記返油回路へ供給する冷媒供給手段が設けられ、当該冷媒供給手段から供給される冷媒と前記返油回路を流れる冷凍機油とを混合する混合手段が、前記異物捕捉手段の上流の前記返油回路に設けられてなるものである。
【００１９】
請求項６記載の発明にかかわる空気調和装置は、前記異物捕捉手段が、液体または気体中の異物を捕捉するフィルターエレメントと、該フィルターエレメントに液体または気体が衝突する際の流速を大きくする衝突速度増大手段とからなり、
前記フィルターエレメントは、焼結金属、セルロース、多孔性陶磁器、ろ紙、多孔質高分子材料、金属網および繊維織布のうちの少なくとも１種の材料で製造されており、
前記衝突速度増大手段は、オリフィス、ノズルおよび細管のうちの少なくとも１つからなるものである。
【００２１】
【発明の実施の形態】
実施の形態１
図１は、本発明の実施の形態１による空気調和装置を説明するための図である。１は圧縮機２、凝縮器３、減圧装置４、蒸発器５を主要構成機器として備えた空気調和装置である。１０は、圧縮機２から凝縮器３に至る冷媒配管６に圧縮機２から吐出された冷媒蒸気中の冷凍機油を分離する油分離器、１１は一方を油分離器１０に接続し他方を蒸発器５から圧縮機２に至る冷媒配管６に接続した返油回路、１３は返油回路１１を流れる冷凍機油の流量を制御する毛細管、３０は冷凍機油中の異物を捕捉する焼結金属フィルター、３１は一方を毛細管から焼結金属フィルター３０に至る返油回路１１に接続し他方を焼結金属フィルター３０から冷媒配管６に至る返油回路１１に接続したバイパス配管、３２はバイパス配管３１に設けた第２の毛細管である。
【００２２】
つぎに図１の空気調和装置の動作について説明する。圧縮機２から吐出された高温高圧の冷媒蒸気と冷凍機油は油分離器１０に流入し、冷凍機油が分離され、冷媒蒸気のみが凝縮器３に流入し空気などと熱交換して凝縮し、高温高圧の冷媒液になる。さらに、減圧装置４で低温低圧の気液二相状態まで減圧され、蒸発器５に流入する。低圧の気液二相冷媒は蒸発器５で空気などと熱交換して蒸発し、圧縮機２に戻る。一方、油分離器１０で分離された冷凍機油は返油回路１１を通り焼結金属フィルター３０で酸化スケールなどの異物が除去され後、冷媒蒸気とともに圧縮機２に戻される。焼結金属フィルター３０で捕捉された異物の量が増加するほど、焼結金属フィルター３０の出入口の圧力差が大きくなり、焼結金属フィルター３０を流れる冷凍機油の流量は次第に減少する。同時に第２の毛細管３２の前後差圧が大きくなり、バイパス配管３１を流れる冷凍機油の流量は増加する。
【００２３】
また、前記実施の形態１ではバイパス配管３１に第２の毛細管３２を用いた空気調和装置について説明したが、焼結金属フィルター３０の出入口の圧力差を測定できる差圧計を設けて、その差圧に応じて流量を制御できる電子式膨張弁を用いてもよい。
【００２４】
また、前記実施の形態１では返油回路１１を流れる異物を除去するために焼結金属フィルター３０を設けた空気調和装置について説明したが、繊維、セルロース、多孔性陶磁器、ろ紙、多孔質高分子材料、金属網または繊維織布などで製造されたフィルターでもよい。
【００２５】
なお、異物捕捉器を構成するフィルターエレメント材として、たとえば以下の表１（化学工学便覧、化学工学協会編、丸善（1988）711頁）に示すものが利用される。
【００２６】
【表１】

【００２７】
実施の形態２
図２は、本発明の実施の形態２による空気調和装置を説明するための図である。図において、４０は逆止弁、４１は焼結金属フィルター３０の上流に設けられた、冷媒液と冷凍機油を混合する混合器、４２は一方を油分離器１０と凝縮器３に至る冷媒配管６に接続し他方を混合器４１に接続した冷媒液配管、４３は油分離器１０から供給される冷媒蒸気を凝縮させる熱交換器、４４は冷媒液配管４２を流れる冷媒液の流量を制御する第３の毛細管である。その他の構成については実施形態１と同様につき説明を省略する。
【００２８】
つぎに図２の空気調和装置の動作について説明する。油分離器１０から凝縮器３に供給される冷媒蒸気の一部は熱交換器４３で凝縮し、第３の毛細管４４を通り混合器４１に送られる。一方、油分離器１０で分離された冷凍機油は毛細管１３、逆止弁４０を通り混合器４１に送られ冷媒液と混合して、冷凍機油中に溶けている冷凍機油の劣化物や添加剤の劣化物が析出する。析出した劣化物と酸化スケールなどの異物は焼結金属フィルター３０で捕捉され、冷凍機油と冷媒のみが冷媒配管６を通り圧縮機２に戻される。焼結金属フィルター３０で捕捉される異物の量が増加するほど、焼結金属フィルター３０の出入口圧力差が大きくなり、焼結金属フィルター３０を流れる冷凍機油の流量は減少し、バイパス配管３１を流れる冷凍機油の流量は増加する。焼結金属フィルター３０で目詰まりを生じたときは油分離器１０で分離された冷凍機油は焼結金属フィルター３０をバイパスして第２の毛細管３２を通り、圧縮機２に戻される。一方、冷媒液は逆止弁４０と目詰まりした焼結金属フィルター３０によって混合器４１に供給されずに凝縮器３、減圧装置４、蒸発器５、圧縮機２の順で循環する。その他の動作については実施形態１と同様につき、説明を省略する。
【００２９】
また、前記実施の形態２ではバイパス配管３１に第２の毛細管３２を設けた空気調和装置について説明したが、焼結金属フィルター３０の出入口の圧力差を測定できる差圧計を設けて、その差圧に応じて流量を制御できる電子式膨張弁を用いてもよい。
【００３０】
また、前記実施の形態２では冷媒液配管に第３の毛細管４４を設けた空気調和装置について説明したが、油分離器１０で分離された冷凍機油の流量を測定または計算できる流量検出手段、たとえば圧縮機の周波数、圧縮機吐出温度、圧縮機吐出圧力、圧縮機吸入温度や圧縮機吸入温度などから冷凍機油の流量を計算できる流量検出手段を設けて、異物捕捉手段による異物の捕捉量が大きくなるように冷媒液の流量の割合を制御できる流量制御手段、たとえば電子式膨張弁などを用いてもよい。
【００３１】
冷媒液と冷凍機油との混合割合の違いによる異物捕捉量の違いについて、本発明者らが行なった実験結果について説明する。図３に実験装置の系統図を示す。１５は冷媒液１６を蓄える冷媒タンク、１７は冷媒液１６を供給する冷媒ポンプ、１８は冷凍機油１９および該冷凍機油の劣化物２０を蓄える油タンク、２１は冷凍機油１９を供給する油ポンプ、２２は冷媒液１６の流量を測定する冷媒流量計、２３は冷凍機油１９の流量を測定する油流量計、２４は冷媒液１６および冷凍機油１９を混合するための水平に設置された配管、２５は公称ろ過精度５μｍの焼結金属フィルター、２６は冷媒液を蒸発させる蒸発器、２７は冷媒蒸気と冷凍機油１９を分離する気液分離器、２８は冷媒蒸気を凝縮させる凝縮器である。
【００３２】
冷媒タンク１５内の冷媒液１６と油タンク１８内の冷凍機油１９は冷媒ポンプ１７および油ポンプ２１によってそれぞれ配管２４に送られ、冷凍機油１９は冷媒液１６に溶ける。同時に、冷凍機油１９に溶けている冷凍機油の劣化物２０は析出して微粒子になり下流の焼結金属フィルター２５で捕捉される。冷媒液１６と冷凍機油１９との混合液体は、蒸発器２６で冷媒液１６のみが蒸発し冷媒蒸気と冷凍機油１９との混合流体となり、気液分離器２７に流入する。流入した冷媒蒸気と冷凍機油１９は気液分離器２７で分離され、冷凍機油１９は油タンク１８に戻り、冷媒蒸気は凝縮器２８で凝縮して冷媒タンク１５に戻る。
【００３３】
図４に冷媒液の流量と冷凍機油の流量の割合を変えたときの実験結果を示す。ただし、冷凍機油の流量と冷凍機油に混ぜた劣化物の量は一定である。横軸は冷媒液と冷凍機油との合計の質量流量に対する冷媒液の質量流量の割合γ（以下混合比という）、縦軸は単位時間あたりの焼結金属フィルターで捕捉された劣化物の量を示す。図４から、混合比γが約０．６３以上のとき焼結金属フィルターで捕捉される劣化物の量が急激に増加していることが判る。したがって、異物捕捉手段の上流に設けられた混合手段で冷媒液と冷凍機油を混合比γ＝０．６３以上で混ぜることによって冷凍機油に溶けている劣化物を異物捕捉手段で捕捉できる。なお、混合比γ＝０．６３は、冷凍機油の質量流量に対する冷媒液の質量流量の割合に換算すると１．７であり、実験誤差を考慮すると１．５である。
【００３４】
また、前記実施の形態２では返油回路を流れる異物を除去するために焼結金属フィルターを用いた空気調和装置について説明したが、繊維、セルロース、多孔性陶磁器、ろ紙、多孔質高分子材料、金属網または繊維織布などで製造されたフィルターでもよい。
【００３５】
また、前記実施の形態２では一方を油分離器１０および凝縮器３に至る冷媒配管６に接続し他方を混合器４１に接続した冷媒液配管４２と、油分離器１０から供給される冷媒蒸気を凝縮させる熱交換器４３と、冷媒液配管４２を流れる冷媒液の流量を制御する第３の毛細管４４を設けた空気調和装置について説明したが、図５に示すように、一方を凝縮器３から減圧装置４に至る冷媒配管６に接続し他方を混合器４１に接続した冷媒液配管４５と、該冷媒液配管４５を流れる冷媒液の流量を制御する第３の毛細管４４を設けてもよい。
【００３６】
実施の形態３
図６は、本発明の実施の形態３による空気調和装置を説明するための図である。図６において、５０は一方を油分離器１０に接続し他方を焼結金属フィルター３０から冷媒配管６に至る返油回路１１に接続したバイパス配管である。その他の構成については実施形態２と同様につき説明を省略する。
【００３７】
つぎに図６の空気調和装置の動作について説明する。油分離器１０で分離された冷凍機油の一部はバイパス配管５０を通り圧縮機２に供給される。焼結金属フィルター３０で捕捉される異物の量が増加するほど、焼結金属フィルター３０の出入口圧力差が大きくなり、焼結金属フィルター３０を流れる冷凍機油の流量は減少する。返油回路１１に冷凍機油は流入しない。また、冷媒液も目詰まりした焼結金属フィルター３０によって混合器４１に供給されない。その他の動作については実施の形態２と同様につき、説明を省略する。
【００３８】
また、前記実施の形態３ではバイパス配管５０に第２の毛細管３２を設けた空気調和装置について説明したが、焼結金属フィルター３０の出入口の圧力差を測定できる差圧計を設けて、その差圧に応じて流量を制御できる電子式膨張弁を用いてもよい。
【００３９】
また、前記実施の形態３では冷媒液配管４２に第３の毛細管４４を設けた空気調和装置について説明したが、油分離器１０で分離された冷凍機油の流量を測定または計算できる流量検出手段、たとえば圧縮機の周波数、圧縮機吐出温度、圧縮機吐出圧力、圧縮機吸入温度や圧縮機吸入温度などから冷凍機油の流量を計算できる流量検出手段を設けて、冷凍機油の流量に対する冷媒液の流量の割合が１．５以上になるように冷媒液の流量を制御できる流量制御手段、たとえば電子式膨張弁などを用いてもよい。
【００４０】
また、前記実施の形態３では返油回路１１を流れる異物を除去するために焼結金属フィルター３０を用いたが、繊維、セルロース、多孔性陶磁器、ろ紙、多孔質高分子材料、金属網または繊維織布などで製造されたフィルターでもよい。
【００４１】
また、図７に示すように返油回路１１が油分離器１０に接続されている高さよりも上方に、バイパス配管５０を接続してもよい。
【００４２】
また、前記実施の形態３では一方を油分離器１０および凝縮器３に至る冷媒配管６に接続し他方を混合器４１に接続した冷媒供給配管４２と、油分離器１０から供給される冷媒蒸気を凝縮させる熱交換器４３と、冷媒液配管４２を流れる冷媒液の流量を制御する冷媒液流量制御手段である第３の毛細管４４とを設けた空気調和装置について説明したが、一方を凝縮器３から減圧装置４に至る冷媒配管６に接続し他方を混合器４１に接続した冷媒供給配管４５と、冷媒供給配管４５を流れる冷媒液の流量を制御する冷媒液流量制御手段とを設けてもよい。
【００４３】
実施の形態４
図８は、本発明の実施の形態４による異物捕捉手段を説明するための図である。図において、７１は異物を捕捉するフィルターエレメント、たとえば焼結金属、繊維、セルロース、多孔性陶磁器、ろ紙、多孔質高分子材料、金属網または繊維織布などのうちの少なくとも１種の材料で製造されたフィルターエレメント、７２はフィルターエレメントに流体が衝突する際の流速を増大させるオリフィス７３が形成された板、７４はフィルターエレメント７１および板７２を収納するケーシングである。
【００４４】
つぎに図８の異物捕捉手段の動作について説明する。異物捕捉手段に供給された流体はオリフィス７３で増速され、フィルターエレメント７１に衝突して、流体中の異物がフィルターエレメント７１で捕捉され、流体中の異物が譲許され異物捕捉手段から流出する。
【００４５】
微細な異物が壁面に沈着する速度は一般的に摩擦速度が大きいほど、流体の粘性が小さいほど、粒子の密度が大きいほど大きくなる。たとえば、単一円孔ノズルを有する衝突板の理論捕集効率は以下の式（１）で示されるストークス数Ｓｋの平方根√Ｓｋが０．３〜０．５の場合に高くなる（粉体工学会編粉体工学便覧第２版、日刊工業新聞社発行、ｐ25）。ここで、ρpは異物の密度、Ccはカニンガムの補正係数、Dpは異物径、u0はノズル内の平均流速、ηは流体の粘度、Wはノズル径である。
【００４６】
Ｓｋ＝ρp×Cc×Dp×2×u0／｛18×η×(W/2)｝（１）
ただし、粒子の反発や再飛散などを生じることがあるため衝突板の種類や性質や状態によって実際の捕捉率は異なる。そこで、発明者らはフィルターエレメントに異物が分散している流体を衝突させる実験を行ない、衝突速度が増大した場合の効果を検証した。実験では１００ｍｇのＪＩＳ試験用粉体Ｉ（２種）を２７ｋｇの冷凍機油に添加し、充分に撹拌しながら公称ろ過精度５μｍ、直径９０ｍｍ、厚さ２ｍｍの円盤状の焼結金属フィルターエレメントでろ過し、フィルターエレメント前後の粒子径ごとの粒子数の時間変化を測定した。衝突速度増大手段として孔径1.5ｍｍのオリフィスを設けた場合、粉体を添加した時点から約２０分で粒径２〜５μｍの粒子の捕捉率が９０％以上に達した。このときのノズル内の流速は９〜１０ｍ／ｓである。オリフィスを設けなかった場合は、粒径２〜５μｍの粒子の捕捉率が９０％以上に達するのに約４０分間要した。このときのフィルターエレメントの前面における平均流速は0.0015〜0.004m/sである。以上の結果から、流体がフィルターエレメントに衝突する際の流速を大きくすることによって粒子を短時間にフィルターエレメントに沈着させて捕捉できる。
【００４７】
また、前記実施の形態４では１個のオリフィス７３を有する異物捕捉手段について説明したが、直径の小さいオリフィスを複数個設けてもよい。
【００４８】
さらに、前記実施の形態４では板状のフィルターエレメント７１を備えた異物捕捉手段について説明したが、図９に示すように、コップ形のフィルターエレメント８０と、フィルターエレメント８０の内径よりも小さい直径を有し側壁に多数のオリフィス８１を有する配管８２と、これらを収納するケーシング８３とで構成された異物捕捉手段でもよい。
【００４９】
また、図１０に示すように筒状のフィルターエレメント９０と、フィルターエレメント９０の内径よりも小さい直径を有し側壁に多数のオリフィス８１を有する配管８２と、フィルターエレメント９０と配管８２を固定する板８４と、これらを収納するケーシング８３とで構成された異物捕捉手段でもよい。
【００５０】
【発明の効果】
本発明は、以上説明したように構成されているので、以下のような効果がある。
【００５１】
請求項１および２記載の発明によれば、異物捕捉手段で異物を捕捉して返油回路を流れる冷凍機油が減少した場合や異物捕捉手段で異物により目詰まりを生じた場合にも、異物捕捉手段で捕捉された異物の量が増加するほど、異物捕捉手段の出入口の圧力差が大きくなり、異物捕捉手段を流れる冷凍機油の流量は減少し、同時に第２の流量制御手段の前後差圧が大きくなり、バイパス手段を流れる冷凍機油の流量が増加するので、冷凍機油を圧縮機に戻すことができる。
【００５２】
請求項３記載の発明によれば、異物捕捉手段で異物を捕捉して返油回路を流れる冷凍機油が減少した場合や異物捕捉手段で異物により目詰まりを生じた場合にも冷凍機油を圧縮機に戻すことができる。また、フィルタからなる異物捕捉手段を利用することによって、安価で、しかも長期にわたり高い信頼性を維持できる。
【００５３】
請求項４記載の発明によれば、異物捕捉手段で異物を捕捉して返油回路を流れる冷凍機油が減少した場合や異物捕捉手段で異物により目詰まりを生じた場合にも冷凍機油を圧縮機に戻すことができる。また、焼結金属などで作製されたフィルタからなる異物捕捉手段を利用することによって、より安価で、しかも長期にわたりより高い信頼性を維持できる。
【００５４】
請求項５記載の発明によれば、請求項１の効果に加えて酸化スケールなどの冷凍機油に溶けない異物、冷凍機油に溶けている冷凍機油の劣化物と添加剤の劣化物を異物捕捉手段で捕捉できる。
【００５６】
請求項６記載の発明によれば、オリフィス、ノズル、毛細管からなる衝突速度増大手段を利用することによって、簡単な構造でフィルターの公称ろ過精度以下の粒子を短時間に多く捕捉できるという効果を実現でき、安価で、しかも長期にわたり高い信頼性を維持できる。
【図面の簡単な説明】
【図１】本発明の実施の形態１による空気調和装置を示す構成図である。
【図２】本発明の実施の形態２による空気調和装置を示す構成図である。
【図３】本発明者らが実施した実験の装置系統図である。
【図４】本発明者らが実施した実験結果である。
【図５】本発明の実施の形態２による空気調和装置を示す構成図である。
【図６】本発明の実施の形態３による冷凍装置を示す構成図である。
【図７】本発明の実施の形態３による冷凍装置を示す構成図である。
【図８】本発明の実施の形態４による異物捕捉手段を示す構成図である。
【図９】本発明の実施の形態４による異物捕捉手段を示す構成図である。
【図１０】本発明の実施の形態４による異物捕捉手段を示す構成図である。
【図１１】従来の冷凍装置を示す構成図である。
【図１２】従来の空気調和装置を示す構成図である。
【符号の説明】
１空気調和装置、２圧縮機、３凝縮器、４減圧装置、５蒸発器、
６冷媒配管、１０油分離器、１１返油回路、１２フィルター、
１３毛細管、１５冷媒タンク、１６冷媒液、１７冷媒ポンプ、
１８油タンク、１９冷凍機油、２０冷凍機油の劣化物、２１油ポンプ、２２冷媒流量計、２３油流量計、２４配管、２５焼結金属フィルター、２６蒸発器、２７気液分離器、２８凝縮器、３０焼結金属フィルター、３１バイパス配管、３２第２の毛細管、４０逆止弁、４１混合器、
４２冷媒液配管、４３熱交換器、４４第３の毛細管、４５冷媒液配管、５０バイパス配管、７１フィルターエレメント、
７２オリフィスを有する板、７３オリフィス、７４ケーシング、
８０フィルターエレメント、８１オリフィス、８２配管、
８３ケーシング、９０フィルターエレメント。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner. More specifically, the present invention relates to an air conditioner applied to an air conditioner used for air conditioning of a house or a building, or a freezing apparatus used for food production processing that is frozen and refrigerated.
[0002]
[Prior art]
FIG. 11 shows a first conventional air conditioner 91 (conventional example 1). A conventional air conditioner 91 shown in FIG. 11 includes a compressor 2, a condenser 3, a decompression device 4, and an evaporator 5 as main components, and a compressor is connected to a refrigerant pipe 6 extending from the compressor 2 to the condenser 3. An oil separator 10 that separates refrigeration oil in the refrigerant vapor discharged from 2, and an oil return circuit 11 that connects one to the oil separator 10 and the other to a refrigerant pipe 6 that leads from the evaporator 5 to the compressor 2. And an oil flow rate control means for controlling the flow rate of the refrigerating machine oil flowing through the oil return circuit 11, for example, a capillary tube 13.
[0003]
Next, the operation of the air conditioner 91 of FIG. 11 will be described. The high-temperature and high-pressure refrigerant vapor discharged from the compressor 2 and the refrigerating machine oil flow into the oil separator 10, the refrigerating machine oil is separated, and only the refrigerant vapor flows into the condenser 3, and is condensed by exchanging heat with air and the like. It becomes a high-temperature and high-pressure refrigerant liquid. Further, the pressure is reduced to a low-temperature low-pressure gas-liquid two-phase state by the pressure reducing device 4 and flows into the evaporator 5. The low-pressure gas-liquid two-phase refrigerant evaporates by exchanging heat with air or the like in the evaporator 5 and is returned to the compressor 2.
[0004]
On the other hand, the refrigerating machine oil separated by the oil separator 10 passes through the oil return circuit 11, and foreign matters are removed by the filter 12, and then returned to the compressor 2 together with the refrigerant vapor.
[0005]
As described above, in the first conventional air conditioner, the moisture, air remaining in the compressor 2 and the refrigerant pipe 6, and the processing oil and the cleaning agent mixed when processing the component equipment are used for the refrigerating machine oil and the refrigerating machine oil. Additives that are mixed deteriorate, and these deteriorated substances adhere to the main components and refrigerant piping of the air conditioner 91. However, hydrochlorofluorocarbon-based refrigerants used as working media until recently have chlorine atoms, so most of the above-mentioned deteriorated materials are dissolved, and there is little occurrence of clogging of pipes and refrigerant pipes constituting main components. .
[0006]
However, from the viewpoint of environmental conservation, the transition to hydrofluorocarbon-based refrigerants that do not contain chlorine atoms has progressed rapidly and circulates in major components and refrigerant pipes without melting them. There is a risk of sticking and clogging. Therefore, the conventional air conditioner uses a filter installed in the oil return circuit to capture the refrigerating machine oil flowing through the refrigerant pipe together with the refrigerant liquid and the deteriorated additive to prevent clogging of the pipe.
[0007]
FIG. 12 shows a second conventional air conditioner 92 (conventional example 2). In FIG. 12, 41 is a mixer provided upstream of the filter 12 for mixing refrigerant liquid and refrigerating machine oil, 42 is connected to the refrigerant pipe 6 leading to the oil separator 10 and the condenser 3, and the other is connected to the mixer 41. The refrigerant liquid pipe 43, a heat exchanger 43 condenses the refrigerant vapor supplied from the oil separator 10, and a third capillary tube 44 for controlling the flow rate of the refrigerant liquid flowing through the refrigerant liquid pipe 42. Other configurations are the same as those in the first conventional example, and the description thereof is omitted.
[0008]
Next, the operation of the air conditioner 92 of FIG. 12 will be described. A part of the refrigerant vapor supplied from the oil separator 10 to the condenser 3 is condensed in the heat exchanger 43 and sent to the mixer 41 through the third capillary 44. On the other hand, the refrigerating machine oil separated by the oil separator 10 passes through the capillary tube 13 and is sent to the mixer 41 where it is mixed with the refrigerant liquid, so that the refrigerating machine oil degradation products and additive degradation products that are dissolved in the refrigerating machine oil are deposited. To do. The deposited deteriorated substances and foreign matters such as oxide scale are captured by the filter 12, and only the refrigerating machine oil and the refrigerant are returned to the compressor 2 through the refrigerant pipe 6. Other operations are the same as those in the first conventional example, and the description thereof is omitted.
[0009]
In the second conventional air conditioner 92 as described above, the deteriorated product of the refrigerating machine oil dissolved in the refrigerating machine oil by injecting the refrigerant supplied from the refrigerant liquid pipe into the refrigerating machine oil flowing through the oil return circuit 11. In addition, the deterioration of the additive and the additive is deposited, and the deterioration that is not soluble in the oxide scale and the refrigerating machine oil and the deterioration that is dissolved in the refrigerating machine oil are captured by the filter 12 to prevent the clogging of the piping due to the oxide scale and the deterioration.
[0010]
[Problems to be solved by the invention]
Refrigerating machine oil and additives are dissolved in refrigerant or refrigerating machine oil before the operation of the air conditioner, but gradually deteriorate with the operation of the air conditioner,
(1) What can be dissolved in refrigerant and refrigerating machine oil at all points in the main components and refrigerant piping of the air conditioner,
(2) Those that are soluble in the refrigerating machine oil but not in the refrigerant liquid, or that are precipitated due to a decrease in solubility due to a decrease in the temperature of the refrigerant,
(3) All of the refrigerant piping and main components do not dissolve in refrigeration oil or refrigerant liquid.
To change. Among these deteriorated products, deteriorated products that have progressed to (2) and (3) cause an increase in pressure loss and clogging of the piping when the refrigerant flows through the refrigerant piping and main components. Regarding the particle size of the deteriorated product, the present inventors have observed foreign matter adhering to the wall surface with an electron microscope, and have confirmed that it is distributed in the range of several μm to several hundred μm.
[0011]
From the above, in the air conditioner 91 of Conventional Example 1 shown in FIG.
1) Clogging occurs when the transmission particle size of the filter is reduced in order to capture a deteriorated product having a particle size distributed over a wide range of several μm to several hundred μm.
2) When the filter is clogged, the refrigerating machine oil is not supplied to the compressor, and the compressor shaft is seized.
3) Degraded product (2) dissolved in refrigerating machine oil cannot be captured, so in an air conditioner using a hydrofluorocarbon refrigerant, degraded product (2) is present in the condenser, evaporator, decompressor, refrigerant piping, etc. Pressure loss when the refrigerant circulates due to adhesion increases and the required capacity cannot be obtained, or the refrigerant does not circulate
There are problems such as.
[0012]
Moreover, in the air conditioning apparatus 92 of the prior art example 2 shown in FIG.
1) Clogging occurs when the transmission particle size of the filter is reduced in order to capture a deteriorated product having a particle size distributed over a wide range of several μm to several hundred μm.
2) When the filter is clogged, the refrigerating machine oil is not supplied to the compressor.
3) Furthermore, as will be described in the second embodiment of the present invention, the deterioration product (2) does not precipitate even if the refrigerant liquid is injected into the refrigerating machine oil depending on the mixing ratio of the refrigerant liquid and the oil. Can not. Therefore, in an air conditioner using a hydrofluorocarbon-based refrigerant, the pressure loss when the deteriorated material (2) adheres to the condenser, the evaporator, the decompression device, the refrigerant pipe, etc. and the refrigerant circulates increases, Refrigerant stops circulating
There are problems such as.
[0013]
The present invention has been made to solve such a problem, and an object of the present invention is to provide an air conditioner capable of supplying refrigerating machine oil to a compressor even when the foreign matter catching means is clogged.
[0014]
[Means for Solving the Problems]
  Claim 1And 2An air conditioner related to the described invention is:BothA compressor, a condenser, a decompression device, and an evaporator are sequentially connected by refrigerant piping,
Further, an oil separator that separates refrigeration oil in the refrigerant vapor discharged from the compressor is connected to a refrigerant pipe extending from the compressor to the condenser, and one is connected to the oil separator and the other is connected from the evaporator to the compressor. An air conditioner including a return oil circuit connected to a refrigerant pipe to reach, and a first oil flow rate control means for controlling a flow rate of refrigerating machine oil in the return oil circuit,
The oil return circuit is provided with a foreign matter catching means capable of catching foreign matter and a bypass means for bypassing the foreign matter catching means,
The bypass means is provided with second oil flow rate control means for controlling the flow rate of the refrigerating machine oil flowing through the bypass means in accordance with the pressure difference between the entrance and exit of the foreign matter capturing means.And
In the invention according to claim 1, the second oil flow rate control means is a capillary tube, and in the invention according to claim 2, the second oil flow rate control means is an electronic expansion valve..
[0015]
  Claim3In the air conditioner according to the described invention, the foreign matter capturing means is formed of a filter.
[0016]
  Claim4In the air conditioner according to the described invention, the filter is made of at least one material selected from the group consisting of sintered metal, cellulose, porous ceramics, filter paper, porous polymer material, metal net, and fiber woven fabric. It will be.
[0017]
  Claim5The air conditioner according to the invention described above is provided with a refrigerant supply means for supplying a part of the refrigerant flowing through the refrigerant pipe to the oil return circuit, and flows through the refrigerant supplied from the refrigerant supply means and the oil return circuit. Mixing means for mixing the refrigerating machine oil is provided in the oil return circuit upstream of the foreign matter capturing means.
[0019]
  The air conditioning apparatus according to the invention of claim 6 is characterized in that the foreign matter catching means has a filter element for catching foreign matter in the liquid or gas, and a collision speed for increasing a flow rate when the liquid or gas collides with the filter element. From increasing meansBecome
The filter element is made of at least one material selected from the group consisting of sintered metal, cellulose, porous ceramics, filter paper, porous polymer material, metal mesh, and fiber woven fabric.
The collision speed increasing means includes at least one of an orifice, a nozzle, and a thin tube.Is.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1
FIG. 1 is a diagram for explaining an air-conditioning apparatus according to Embodiment 1 of the present invention. Reference numeral 1 denotes an air conditioner including a compressor 2, a condenser 3, a pressure reducing device 4, and an evaporator 5 as main components. 10 is an oil separator that separates refrigeration oil in the refrigerant vapor discharged from the compressor 2 into a refrigerant pipe 6 extending from the compressor 2 to the

condenser

3, and 11 is connected to the oil separator 10 and one is evaporated. An oil return circuit connected to the refrigerant pipe 6 extending from the compressor 5 to the

compressor

2, 13 is a capillary tube for controlling the flow rate of the refrigerating machine oil flowing through the oil return circuit 11, 30 is a sintered metal filter for capturing foreign matter in the refrigerating machine oil, A bypass pipe 31 is connected to the oil return circuit 11 extending from the capillary tube to the sintered metal filter 30 and the other is connected to the oil return circuit 11 extending from the sintered metal filter 30 to the refrigerant pipe 6. 32 is provided in the bypass pipe 31. A second capillary.
[0022]
Next, the operation of the air conditioner of FIG. 1 will be described. The high-temperature and high-pressure refrigerant vapor discharged from the compressor 2 and the refrigerating machine oil flow into the oil separator 10, the refrigerating machine oil is separated, and only the refrigerant vapor flows into the condenser 3 for heat exchange with air and condensing. It becomes a high-temperature and high-pressure refrigerant liquid. Further, the pressure is reduced to a low-temperature low-pressure gas-liquid two-phase state by the pressure reducing device 4 and flows into the evaporator 5. The low-pressure gas-liquid two-phase refrigerant evaporates by exchanging heat with air or the like in the evaporator 5 and returns to the compressor 2. On the other hand, the refrigerating machine oil separated by the oil separator 10 passes through the oil return circuit 11, and foreign substances such as oxide scale are removed by the sintered metal filter 30, and then returned to the compressor 2 together with the refrigerant vapor. As the amount of foreign matter trapped by the sintered metal filter 30 increases, the pressure difference between the inlet and outlet of the sintered metal filter 30 increases, and the flow rate of the refrigerating machine oil flowing through the sintered metal filter 30 gradually decreases. At the same time, the differential pressure across the second capillary 32 increases, and the flow rate of the refrigerating machine oil flowing through the bypass pipe 31 increases.
[0023]
In the first embodiment, the air conditioner using the second capillary 32 as the bypass pipe 31 has been described. However, a differential pressure gauge that can measure the pressure difference at the entrance and exit of the sintered metal filter 30 is provided, and the differential pressure is provided. You may use the electronic expansion valve which can control a flow volume according to.
[0024]
In the first embodiment, the air conditioner provided with the sintered metal filter 30 in order to remove foreign matters flowing through the oil return circuit 11 has been described. However, fibers, cellulose, porous ceramics, filter paper, porous polymers The filter may be made of a material, a metal net or a fiber woven fabric.
[0025]
In addition, as a filter element material which comprises a foreign material trap, for example, those shown in the following Table 1 (Chemical Engineering Handbook, edited by Chemical Engineering Association, Maruzen (1988) page 711) are used.
[0026]
[Table 1]

[0027]
Embodiment 2
FIG. 2 is a diagram for explaining an air-conditioning apparatus according to Embodiment 2 of the present invention. In the figure, 40 is a check valve, 41 is a mixer provided upstream of the sintered metal filter 30 for mixing refrigerant liquid and refrigerating machine oil, and 42 is a refrigerant pipe that leads one to the oil separator 10 and the condenser 3. 6 is connected to the mixer 41 and the other is connected to the

mixer

41, 43 is a heat exchanger for condensing the refrigerant vapor supplied from the

oil separator

10, and 44 controls the flow rate of the refrigerant liquid flowing through the refrigerant liquid pipe 42. A third capillary. Other configurations are the same as those in the first embodiment, and a description thereof is omitted.
[0028]
Next, the operation of the air conditioner of FIG. 2 will be described. A part of the refrigerant vapor supplied from the oil separator 10 to the condenser 3 is condensed in the heat exchanger 43 and sent to the mixer 41 through the third capillary 44. On the other hand, the refrigerating machine oil separated by the oil separator 10 is sent to the mixer 41 through the capillary tube 13 and the check valve 40 and mixed with the refrigerant liquid, and the refrigerating machine oil deterioration products and additives dissolved in the refrigerating machine oil. A deteriorated product is deposited. The deposited deteriorated substances and foreign matters such as oxide scale are captured by the sintered metal filter 30, and only the refrigerating machine oil and the refrigerant are returned to the compressor 2 through the refrigerant pipe 6. As the amount of foreign matter captured by the sintered metal filter 30 increases, the inlet / outlet pressure difference of the sintered metal filter 30 increases, the flow rate of the refrigerating machine oil flowing through the sintered metal filter 30 decreases, and flows through the bypass pipe 31. The flow rate of refrigeration oil increases. When clogging occurs in the sintered metal filter 30, the refrigerating machine oil separated by the oil separator 10 bypasses the sintered metal filter 30, passes through the second capillary 32, and is returned to the compressor 2. On the other hand, the refrigerant liquid circulates in the order of the condenser 3, the decompressor 4, the evaporator 5, and the compressor 2 without being supplied to the mixer 41 by the check valve 40 and the clogged sintered metal filter 30. Other operations are the same as those in the first embodiment, and a description thereof will be omitted.
[0029]
In the second embodiment, the air conditioner in which the second capillary 32 is provided in the bypass pipe 31 has been described. However, a differential pressure gauge that can measure the pressure difference at the entrance and exit of the sintered metal filter 30 is provided, and the differential pressure is provided. You may use the electronic expansion valve which can control a flow volume according to.
[0030]
In the second embodiment, the air conditioner in which the third capillary 44 is provided in the refrigerant liquid pipe has been described. However, the flow rate detecting means capable of measuring or calculating the flow rate of the refrigerating machine oil separated by the oil separator 10, for example, A flow rate detection means that can calculate the flow rate of refrigeration oil from the compressor frequency, compressor discharge temperature, compressor discharge pressure, compressor suction temperature, compressor suction temperature, etc. is provided, and the amount of foreign matter captured by the foreign matter catching means is large. A flow rate control means capable of controlling the ratio of the flow rate of the refrigerant liquid, such as an electronic expansion valve, may be used.
[0031]
The results of experiments conducted by the present inventors will be described regarding the difference in the amount of foreign matter captured due to the difference in the mixing ratio between the refrigerant liquid and the refrigerating machine oil. FIG. 3 shows a system diagram of the experimental apparatus. 15 is a refrigerant tank that stores the

refrigerant liquid

16, 17 is a refrigerant pump that supplies the

refrigerant liquid

16, 18 is an oil tank that stores the refrigerating machine oil 19 and a deteriorated product 20 of the refrigerating machine oil, and 21 is an oil pump that supplies the refrigerating machine oil 19. 22 is a refrigerant flow meter for measuring the flow rate of the

refrigerant liquid

16, 23 is an oil flow meter for measuring the flow rate of the refrigerating

machine oil

19, 24 is a horizontally installed pipe for mixing the refrigerant liquid 16 and the refrigerating

machine oil

19, 25 Is a sintered metal filter having a nominal filtration accuracy of 5 μm, 26 is an evaporator for evaporating the refrigerant liquid, 27 is a gas-liquid separator for separating the refrigerant vapor and the refrigerating

machine oil

19, and 28 is a condenser for condensing the refrigerant vapor.
[0032]
The refrigerant liquid 16 in the refrigerant tank 15 and the refrigerating machine oil 19 in the oil tank 18 are respectively sent to the pipe 24 by the refrigerant pump 17 and the oil pump 21, and the refrigerating machine oil 19 is dissolved in the refrigerant liquid 16. At the same time, the deteriorated product 20 of the refrigerating machine oil dissolved in the refrigerating machine oil 19 is precipitated and becomes fine particles and is captured by the downstream sintered metal filter 25. In the mixed liquid of the refrigerant liquid 16 and the refrigerating machine oil 19, only the refrigerant liquid 16 evaporates in the evaporator 26, becomes a mixed fluid of the refrigerant vapor and the refrigerating machine oil 19, and flows into the gas-liquid separator 27. The flowing refrigerant vapor and the refrigerating machine oil 19 are separated by the gas-liquid separator 27, the refrigerating machine oil 19 is returned to the oil tank 18, and the refrigerant vapor is condensed by the condenser 28 and returned to the refrigerant tank 15.
[0033]
FIG. 4 shows the experimental results when the ratio between the flow rate of the refrigerant liquid and the flow rate of the refrigerating machine oil is changed. However, the flow rate of the refrigerating machine oil and the amount of the deteriorated material mixed with the refrigerating machine oil are constant. The horizontal axis represents the ratio γ of the mass flow rate of the refrigerant liquid to the total mass flow rate of the refrigerant liquid and the refrigerating machine oil (hereinafter referred to as the mixing ratio), and the vertical axis represents the amount of deteriorated material captured by the sintered metal filter per unit time. Show. From FIG. 4, it can be seen that when the mixing ratio γ is about 0.63 or more, the amount of the deteriorated product captured by the sintered metal filter increases rapidly. Therefore, the foreign matter catching means can catch the deteriorated material dissolved in the refrigerating machine oil by mixing the refrigerant liquid and the refrigerating machine oil at a mixing ratio γ = 0.63 or more by the mixing means provided upstream of the foreign matter catching means. The mixing ratio γ = 0.63 is 1.7 when converted to the ratio of the mass flow rate of the refrigerant liquid to the mass flow rate of the refrigerating machine oil, and 1.5 considering the experimental error.
[0034]
In the second embodiment, an air conditioner using a sintered metal filter to remove foreign substances flowing through the oil return circuit has been described. However, fibers, cellulose, porous ceramics, filter paper, porous polymer materials, It may be a filter made of metal mesh or fiber woven fabric.
[0035]
In the second embodiment, the refrigerant liquid pipe 42, one of which is connected to the refrigerant pipe 6 reaching the oil separator 10 and the condenser 3 and the other is connected to the mixer 41, and the refrigerant vapor supplied from the oil separator 10 The air conditioner provided with the heat exchanger 43 that condenses the refrigerant and the third capillary 44 that controls the flow rate of the refrigerant liquid flowing through the refrigerant liquid pipe 42 has been described. However, as shown in FIG. A refrigerant liquid pipe 45 that is connected to the refrigerant pipe 6 extending from to the decompression device 4 and the other is connected to the mixer 41, and a third capillary 44 that controls the flow rate of the refrigerant liquid flowing through the refrigerant liquid pipe 45 may be provided. .
[0036]
Embodiment 3
FIG. 6 is a diagram for explaining an air-conditioning apparatus according to Embodiment 3 of the present invention. In FIG. 6, reference numeral 50 denotes a bypass pipe having one connected to the oil separator 10 and the other connected to the oil return circuit 11 extending from the sintered metal filter 30 to the refrigerant pipe 6. Other configurations are the same as those in the second embodiment, and a description thereof will be omitted.
[0037]
Next, the operation of the air conditioner of FIG. 6 will be described. A part of the refrigerating machine oil separated by the oil separator 10 is supplied to the compressor 2 through the bypass pipe 50. As the amount of foreign matter captured by the sintered metal filter 30 increases, the inlet / outlet pressure difference of the sintered metal filter 30 increases and the flow rate of the refrigerating machine oil flowing through the sintered metal filter 30 decreases. The refrigerating machine oil does not flow into the oil return circuit 11. Further, the refrigerant liquid is not supplied to the mixer 41 by the clogged sintered metal filter 30. Other operations are the same as those in the second embodiment, and a description thereof will be omitted.
[0038]
In the third embodiment, the air conditioner having the second capillary 32 provided in the bypass pipe 50 has been described. However, a differential pressure gauge that can measure the pressure difference at the entrance and exit of the sintered metal filter 30 is provided, and the differential pressure is provided. You may use the electronic expansion valve which can control a flow volume according to.
[0039]
In the third embodiment, the air conditioner in which the third capillary tube 44 is provided in the refrigerant liquid pipe 42 has been described. However, the flow rate detecting means capable of measuring or calculating the flow rate of the refrigerating machine oil separated by the oil separator 10; For example, a flow rate detection means that can calculate the flow rate of refrigeration oil from the compressor frequency, compressor discharge temperature, compressor discharge pressure, compressor suction temperature, compressor suction temperature, etc. A flow rate control means capable of controlling the flow rate of the refrigerant liquid so that the ratio of the ratio is 1.5 or more, such as an electronic expansion valve, may be used.
[0040]
In the third embodiment, the sintered metal filter 30 is used to remove foreign substances flowing in the oil return circuit 11, but fibers, cellulose, porous ceramics, filter paper, porous polymer materials, metal nets or fibers A filter made of woven fabric or the like may be used.
[0041]
Further, as shown in FIG. 7, the bypass pipe 50 may be connected above the height at which the oil return circuit 11 is connected to the oil separator 10.
[0042]
In the third embodiment, the refrigerant supply pipe 42, one of which is connected to the refrigerant pipe 6 reaching the oil separator 10 and the condenser 3 and the other is connected to the mixer 41, and the refrigerant vapor supplied from the oil separator 10 The air conditioner provided with the heat exchanger 43 that condenses the refrigerant and the third capillary 44 that is the refrigerant liquid flow rate control means for controlling the flow rate of the refrigerant liquid flowing through the refrigerant liquid pipe 42 has been described. The refrigerant supply pipe 45 connected to the refrigerant pipe 6 extending from 3 to the decompression device 4 and the other connected to the mixer 41, and the refrigerant liquid flow rate control means for controlling the flow rate of the refrigerant liquid flowing through the refrigerant supply pipe 45 may be provided. Good.
[0043]
Embodiment 4
FIG. 8 is a diagram for explaining a foreign matter catching means according to Embodiment 4 of the present invention. In the figure, reference numeral 71 denotes a filter element that traps foreign matters, for example, at least one material selected from sintered metal, fiber, cellulose, porous ceramics, filter paper, porous polymer material, metal net, or fiber woven fabric. The filter element 72 is a plate on which an orifice 73 is formed to increase the flow velocity when a fluid collides with the filter element, and 74 is a casing for housing the filter element 71 and the plate 72.
[0044]
Next, the operation of the foreign matter capturing means of FIG. 8 will be described. The fluid supplied to the foreign matter catching means is accelerated at the orifice 73 and collides with the filter element 71. The foreign matter in the fluid is caught by the filter element 71, and the foreign matter in the fluid is consigned and flows out from the foreign matter catching means. .
[0045]
In general, the speed at which fine foreign substances are deposited on the wall surface increases as the friction speed increases, the fluid viscosity decreases, and the particle density increases. For example, the theoretical collection efficiency of a collision plate having a single circular nozzle is high when the square root √Sk of the Stokes number Sk represented by the following formula (1) is 0.3 to 0.5 (powder processing) The Society of Powder Engineering Handbook 2nd edition, published by Nikkan Kogyo Shimbun, p25). Here, ρp is the density of foreign matter, Cc is the Cunningham correction coefficient, Dp is the foreign matter diameter, u0 is the average flow velocity in the nozzle, η is the viscosity of the fluid, and W is the nozzle diameter.
[0046]
Sk = ρp × Cc × Dp × 2 × u0 / {18 × η × (W / 2)} (1)
However, since the particles may be repelled or re-scattered, the actual capture rate varies depending on the type, nature, and state of the collision plate. Therefore, the inventors conducted an experiment in which a fluid in which foreign matter was dispersed collided with the filter element, and verified the effect when the collision speed increased. In the experiment, 100 mg of JIS test powder I (2 types) was added to 27 kg of refrigerating machine oil, and filtered with a disc-shaped sintered metal filter element with a nominal filtration accuracy of 5 μm, a diameter of 90 mm, and a thickness of 2 mm with sufficient stirring. Then, the time change of the number of particles for each particle diameter before and after the filter element was measured. When an orifice with a hole diameter of 1.5 mm was provided as means for increasing the collision speed, the trapping rate of particles having a particle diameter of 2 to 5 μm reached 90% or more in about 20 minutes from the time when the powder was added. The flow velocity in the nozzle at this time is 9 to 10 m / s. When no orifice was provided, it took about 40 minutes for the trapping rate of particles having a particle diameter of 2 to 5 μm to reach 90% or more. At this time, the average flow velocity at the front surface of the filter element is 0.0015 to 0.004 m / s. From the above results, by increasing the flow velocity when the fluid collides with the filter element, the particles can be deposited and captured on the filter element in a short time.
[0047]
In the fourth embodiment, the foreign substance capturing means having one orifice 73 has been described. However, a plurality of orifices having a small diameter may be provided.
[0048]
Further, in the fourth embodiment, the foreign matter capturing means including the plate-like filter element 71 has been described. However, as shown in FIG. 9, a cup-shaped filter element 80 and a diameter smaller than the inner diameter of the filter element 80 are used. It may be a foreign substance capturing means constituted by a pipe 82 having a large number of orifices 81 on the side wall and a casing 83 for storing them.
[0049]
Further, as shown in FIG. 10, a cylindrical filter element 90, a pipe 82 having a diameter smaller than the inner diameter of the filter element 90 and having a large number of orifices 81 on the side wall, and a plate for fixing the filter element 90 and the pipe 82 A foreign matter catching means constituted by 84 and a casing 83 for storing them may be used.
[0050]
【The invention's effect】
Since the present invention is configured as described above, the following effects are obtained.
[0051]
  Claim 1And 2According to the described invention, even when the refrigeration oil flowing through the oil return circuit is reduced by capturing the foreign matter by the foreign matter capturing means or when the foreign matter catching means causes clogging by the foreign matter, the foreign matter catching means captures the foreign matter. As the amount of foreign matter increases, the pressure difference at the entrance and exit of the foreign matter catching means increases, the flow rate of the refrigerating machine oil flowing through the foreign matter catching means decreases, and at the same time, the differential pressure across the second flow rate control means increases and the bypass means. Since the flow rate of the refrigeration oil flowing through the refrigerant increases, the refrigeration oil can be returned to the compressor.
[0052]
  Claim3According to the described invention, the refrigerating machine oil is returned to the compressor even when the refrigerating machine oil flowing through the oil return circuit is reduced by the foreign object catching means or when the foreign matter catching means causes clogging. Can do. Further, by using a foreign matter capturing means comprising a filter, it is inexpensive and can maintain high reliability over a long period of time.
[0053]
  Claim4According to the described invention, the refrigerating machine oil is returned to the compressor even when the refrigerating machine oil flowing through the oil return circuit is reduced by the foreign object catching means or when the foreign matter catching means causes clogging. Can do. In addition, by using a foreign matter capturing means made of a filter made of sintered metal or the like, it is possible to maintain higher reliability at a lower cost and for a long time.
[0054]
  Claim5According to the described invention, in addition to the effect of the first aspect, the foreign matter insoluble in the refrigerating machine oil such as oxide scale, the deteriorated product of the refrigerating machine oil and the additive deteriorated in the refrigerating machine oil can be captured by the foreign material capturing means. .
[0056]
  According to the invention described in claim 6,By using a collision speed increasing means consisting of an orifice, nozzle, and capillary tube, the structure is simple.Capturing many particles below the nominal filtration accuracy of the filter in a short timeCan be realized, inexpensive, and can maintain high reliability over a long period of time.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an air conditioner according to Embodiment 1 of the present invention.
FIG. 2 is a block diagram showing an air conditioner according to Embodiment 2 of the present invention.
FIG. 3 is a system diagram of an experiment performed by the present inventors.
FIG. 4 is a result of an experiment conducted by the present inventors.
FIG. 5 is a block diagram showing an air conditioner according to Embodiment 2 of the present invention.
FIG. 6 is a configuration diagram showing a refrigeration apparatus according to Embodiment 3 of the present invention.
FIG. 7 is a configuration diagram showing a refrigeration apparatus according to Embodiment 3 of the present invention.
FIG. 8 is a configuration diagram showing a foreign matter capturing means according to a fourth embodiment of the present invention.
FIG. 9 is a configuration diagram showing a foreign matter capturing means according to a fourth embodiment of the present invention.
FIG. 10 is a configuration diagram showing a foreign matter capturing means according to a fourth embodiment of the present invention.
FIG. 11 is a configuration diagram showing a conventional refrigeration apparatus.
FIG. 12 is a configuration diagram showing a conventional air conditioner.
[Explanation of symbols]
1 air conditioner, 2 compressor, 3 condenser, 4 decompressor, 5 evaporator,
6 Refrigerant piping, 10 Oil separator, 11 Oil return circuit, 12 Filter,
13 Capillary tube, 15 Refrigerant tank, 16 Refrigerant liquid, 17 Refrigerant pump,
18 Oil tank, 19 Refrigerator oil, 20 Refrigerator oil degradation product, 21 Oil pump, 22 Refrigerant flow meter, 23 Oil flow meter, 24 Piping, 25 Sintered metal filter, 26 Evaporator, 27 Gas-liquid separator, 28 Condensation 30 sintered metal filter, 31 bypass pipe, 32 second capillary, 40 check valve, 41 mixer,
42 refrigerant liquid piping, 43 heat exchanger, 44 third capillary tube, 45 refrigerant liquid piping, 50 bypass piping, 71 filter element,
72 orifice plate, 73 orifice, 74 casing,
80 filter element, 81 orifice, 82 piping,
83 Casing, 90 Filter element.

Claims

A compressor, a condenser, a pressure reducing device, and an evaporator are sequentially connected by refrigerant piping,
Furthermore, an oil separator that separates refrigeration oil in the refrigerant vapor discharged from the compressor is connected to a refrigerant pipe from the compressor to the condenser, one is connected to the oil separator, and the other is connected from the evaporator to the compressor. An air conditioner including a return oil circuit connected to a refrigerant pipe to reach, and a first oil flow rate control means for controlling a flow rate of refrigerating machine oil in the return oil circuit,
The oil return circuit is provided with a foreign matter catching means capable of catching foreign matter and a bypass means for bypassing the foreign matter catching means,
The bypass means is provided with a second oil flow rate control means for controlling the flow rate of the refrigerating machine oil flowing through the bypass means according to the pressure difference between the inlet and outlet of the foreign matter capturing means ,
The air conditioner according to claim 2, wherein the second oil flow rate control means is a capillary tube .

A compressor, a condenser, a decompression device, and an evaporator are sequentially connected by refrigerant piping,
Further, an oil separator that separates refrigeration oil in the refrigerant vapor discharged from the compressor is connected to a refrigerant pipe extending from the compressor to the condenser, and one is connected to the oil separator and the other is connected from the evaporator to the compressor. An air conditioner including a return oil circuit connected to a refrigerant pipe to reach, and a first oil flow rate control means for controlling a flow rate of refrigerating machine oil in the return oil circuit,
The oil return circuit is provided with a foreign matter catching means capable of catching foreign matter, a bypass means for bypassing the foreign matter catching means, and a differential pressure gauge for measuring a pressure difference between the entrance and exit of the foreign matter catching means,
The bypass means is provided with second oil flow rate control means for controlling the flow rate of the refrigerating machine oil flowing through the bypass means according to the pressure difference measured by the differential pressure gauge,
The second oil flow rate control means is an electronic expansion valve
Air conditioner.

The air conditioner according to claim 1 or 2 , wherein the foreign matter capturing means comprises a filter.

The air conditioner according to claim 3 , wherein the filter is made of at least one material selected from sintered metal, cellulose, porous ceramics, filter paper, porous polymer material, metal net, and fiber woven fabric.

Refrigerant supply means for supplying a part of the refrigerant flowing through the refrigerant pipe to the oil return circuit is provided, and mixing means for mixing the refrigerant supplied from the refrigerant supply means and the refrigerating machine oil flowing through the oil return circuit, The air conditioner according to claim 1 or 2 , wherein the air conditioner is provided in the oil return circuit upstream of the foreign matter capturing means.

The foreign matter capturing means comprises a filter element that captures foreign matter in a liquid or gas, and a collision speed increasing means that increases a flow rate when the liquid or gas collides with the filter element,
The filter element is made of at least one material of sintered metal, fiber, cellulose, porous ceramic, filter paper, porous polymer material, metal net or fiber woven fabric,
The air conditioner according to claim 1 or 2 , wherein the collision speed increasing means includes at least one of an orifice, a nozzle, and a thin tube.