JP3638976B2

JP3638976B2 - Refrigeration equipment

Info

Publication number: JP3638976B2
Application number: JP30496594A
Authority: JP
Inventors: 浩中田; 誠夫木村
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 1994-12-08
Filing date: 1994-12-08
Publication date: 2005-04-13
Anticipated expiration: 2020-04-13
Also published as: JPH08159578A

Description

【０００１】
【産業上の利用分野】
この発明は、例えばスーパーマーケットの低温商品ケース，冷蔵庫，冷凍庫等で使用される冷凍装置の信頼性向上、及び市場でのサービス性向上に関するものである。
【０００２】
【従来の技術】
図７は従来の冷凍装置、例えば三菱電機冷熱ハンドブック（１９９３年版）に記載された冷媒配管系統を示す図である。図において、１は冷媒圧縮機、２は凝縮器、３は上記凝縮器２で凝縮された液冷媒を収容する液溜、４は上記液溜３の液冷媒を送出する液配管、５は減圧装置、６は蒸発器、７は気液分離器、８は上記気液分離器７と上記冷媒圧縮機１とを接続し上記気液分離器７内に設けられたＵ字管を有する吸入配管、９は上記吸入配管８の接続口８ａから上記気液分離器７の接続口７ａへ連通する均液管である。上記均液管９と気液分離器７との接続口７ａは冷媒圧縮機１の吸入口１ａよりも下方位置に設けられている。
続いて、１０は冷媒回路中に設けた油分離器１１から上記吸入配管８へ連通する返油管である。１２，１３は開閉弁であり、市場（例えば、装置出荷先）で冷媒圧縮機１を交換する際などに回路内の冷媒を全量放出しなくても済むように冷媒回路を遮断する目的で設けられている。開閉弁１２は冷媒回路中、返油管１０と連通する吸入配管８の接続口８ｂよりも冷媒流通方向の上流側に設けられ、開閉弁１３は油分離器１１と凝縮器２との間に設けられている。
【０００３】
従来の冷凍装置は上記のように構成され、例えば冷媒圧縮機１で圧縮された高温高圧の冷媒は、油分離器１１で高温高圧のガス冷媒と油とに分離される。油分離器１１より送出された高温高圧のガス冷媒は凝縮器２で凝縮されて液化し、この液冷媒は液溜３に収容される。液溜３から液配管４を介して送出された液冷媒の減圧装置５で減圧されて気液二相の状態となり、蒸発器６で外気と熱交換してガス化し、気液分離器７、吸入配管８を経て再び冷媒圧縮機１へ戻り、上記のような冷媒サイクルを繰り返す。
【０００４】
また、油分離器１１で分離された油は、返油管１０を通り吸入配管８を介して再び冷媒圧縮機１へ戻り、このような油サイクルを繰り返す。なお、油は冷媒圧縮機１が故障することなく適正な運転をおこなえるように、常に安定して戻るようになっている。
そして、運転条件等の変化によって蒸発器６で蒸発しきれなかった液冷媒は気液分離器７に収容され、ここで気液分離されたガス冷媒を吸入配管８を介して冷媒圧縮機１へ戻り、上記のような冷媒サイクルを繰り返す。
次に、冷凍装置を長時間停止した場合、冷媒は冷媒圧縮機１内で液冷媒として油とともに寝込む。そして、かかる液冷媒が冷媒圧縮機１の上部まで寝込むのを防止するため、この装置では多量に寝込んだ液冷媒が吸入配管８から均液管９を経て気液分離器７へ戻るようになっている。
【０００５】
油分離器１１で分離された油は返油管１０を通り吸入配管８を介して冷媒圧縮機１へ戻るようになっている。従って通常時、冷媒圧縮機１内の油が不足することなく運転を続けることができる。
また、市場で冷媒圧縮機１を交換する場合は、開閉弁１２，１３を閉じることにより、冷媒回路を遮断して行われる。この際、回路内の冷媒を若干放出しなければならないが、液溜３などに冷媒の大部分が収容されているので、多量の冷媒を放出することなく交換サービスを行うことができる。そして、冷媒圧縮機１を交換して回路を復旧させた後、冷媒圧縮機１側の開閉弁１２〜１３間の回路内を真空引きし、再び開閉弁１２，１３を開けて冷凍装置の運転を再開させるようになっている。
【０００６】
【発明が解決しようとする課題】
従来の冷凍装置は以上のように構成されているので、運転条件等の変化によって冷媒圧縮機１吸入側へ液冷媒が戻るような場合に、気液分離器７内に多量の液冷媒が保持されるが、均液管９を経て液冷媒がそのまま冷媒圧縮機１へ吸入されることがあり、冷媒圧縮機１が液冷媒の液圧縮により損傷するおそれがあった。また、液冷媒を気液分離器７に確実に戻すためには気液分離器７の高さを低く製作することが考えられるが、容量を確保する為設置面積が広くなり他の機器の設置空間を占有することになるため、装置全体の設置面積が大きくなりコスト高となるといった問題があった。
更に、市場でのサービス時に、冷媒圧縮機１の吐出管より真空引きを行うと、油分離器１１の返油管１０を通じて気液分離器７内の冷媒も引いてしまうことになるため、冷媒圧縮機１のみを真空引きすることができず、真空引き作業に長時間かかるという問題があった。
【０００７】
この発明は、かかる問題点を解決するためになされたものであり、冷凍装置の信頼性をより向上させるため、吸入配管内の液冷媒を確実に気液分離器に戻すとともに、液冷媒のままで冷媒圧縮機へ吸入されることによる故障を防いで適正な運転の実現、および市場での真空引き等のサービスを短時間で確実に実施できる冷凍装置の提供を目的としている。
【０００８】
【課題を解決するための手段】
この発明に係る冷凍装置は、複数基並列配置された冷媒圧縮機，凝縮器，減圧装置，蒸発器，気液分離器，及び、気液分離器と冷媒圧縮機との間にそれぞれ介設され、気液分離器内に設けられたＵ字管を有する複数の吸入配管を順次接続して冷媒回路を構成するとともに、吸入配管と気液分離器とにそれぞれ接続され各吸入配管の液冷媒を気液分離器に戻すための複数の均液管を有し、均液管のそれぞれの気液分離器側近傍を合流させて合流均液管を形成し、合流均液管に第２の逆止弁を当該冷媒流通許容方向を気液分離器に向けて配設したものである。
【０００９】
また、上述の構成において、冷媒圧縮機と凝縮器との間に介設された油分離器と、冷媒圧縮機の吸入側と油分離器の冷媒出側とにそれぞれ設けられ冷媒回路を遮断可能の開閉弁と、油分離器と吸入配管とを接続する返油管とを備え、返油管に第３の逆止弁を当該冷媒流通許容方向を吸入配管に向けて配設したものである。
【００１０】
【作用】
この発明によれば、複数基の冷媒圧縮機を並列配備した冷媒回路の場合に、通常運転時における各吸入配管の液冷媒は、各均液管，合流均液管，第２の逆止弁を経て気液分離器に戻る一方、気液分離器内の液冷媒量が多くなった場合には、第２の逆止弁の存在により、気液分離器の液冷媒が各均液管へ短絡して流通することが阻止される。そのうえ、第２の逆止弁は少なくとも一つだけで済み、冷媒圧縮機全数分の逆止弁を必要としないので、装置を安価に製造できる。
【００１１】
また、冷媒圧縮機の吸入側の開閉弁と油分離器の冷媒出側の開閉弁とが閉じられることにより、冷媒回路が各開閉弁の位置で遮断される。このとき、凝縮器，減圧装置，蒸発器，気液分離器，および吸入配管までの比較的容量の大きな回路内空間は、各開閉弁と第３の逆止弁とで密封される。従って、冷媒圧縮機および油分離器まわりの冷媒回路が分解された場合に、外部に流出する冷媒量は少量ですむ。そして、冷媒圧縮機が交換され冷媒回路の組立復旧後には、冷媒圧縮機および油分離器といった各開閉弁間の比較的小さな機器内空間を真空引きするだけですむ。
【００１２】
【実施例】
実施例１．
図１はこの発明による実施例１を示す冷凍装置の冷媒配管系統図であり、１〜１３は従来装置と全く同一のものであるので、それらの詳細説明は省略する。また、図において、１４は均液管９の途中に設けられている第１の逆止弁であり、この場合気液分離器７内に設けられたＵ字管を有する吸入配管８から気液分離器７へ向かう方向にしか、冷媒が流通しないように配設されている（図中の矢印が冷媒流通許容方向を示す）。
【００１３】
この実施例のように構成された冷凍装置においては、例えば冷媒圧縮機１で圧縮された高温高圧の冷媒等は、油分離器１１で高温高圧のガス冷媒と油とに分離される。油分離器１１より送出された高温高圧のガス冷媒は凝縮器２で凝縮されて液化し、液冷媒は液溜３に収容される。液溜３から液配管４を介して送出された液冷媒は減圧装置５で減圧されて気液二相の状態となり、蒸発器６で外気と熱交換してガス化し、気液分離器７、吸入配管８を通り再び冷媒圧縮機１へ戻り上記のような冷媒サイクルを繰り返す。
また、油分離器１１で分離された油は返油管１０を通り吸入配管８を介して再び冷媒圧縮機１へ戻り、上記のような油サイクルを繰り返す。なお、油は冷媒圧縮機１が故障することなく適正な運転ができるように常に安定して戻るようになっている。
【００１４】
また、運転条件等の変化によって蒸発器６で蒸発しきれなかった液冷媒は気液分離器７に収容され、ここで気液分離されたガス冷媒が吸入配管８を介して冷媒圧縮機１へ戻り、上記のような冷媒サイクルを繰り返す。
また、運転条件等の変化によって液冷媒が冷媒圧縮機１に戻るような時には、気液分離器７内の液冷媒は均液管９を経て冷媒圧縮機１へ流入しようとするが、均液管９には第１の逆止弁１４が取り付けられているため、気液分離器７の液冷媒がそのまま冷媒圧縮機１へ向かって流れることは阻止される。よって、冷媒圧縮機１の液冷媒吸入による故障（液圧縮による損傷）を防ぐことができる。また、長期停止中に液冷媒が冷媒圧縮機１に寝込んだ場合に冷媒圧縮機１の上部まで寝込まぬように、吸入配管８の液冷媒は均液管９を通じて気液分離器７へ戻ることができる。
【００１５】
実施例２．
図２はこの発明による実施例２を示す冷凍装置の冷媒配管系統図であり、冷媒圧縮機が２基並列配備された構成を示した図である。図において、１５は気液分離器７内に設けられたＵ字管を有する第１吸入配管、１６は気液分離器７内に設けられたＵ字管を有する第２吸入配管、１７は第１冷媒圧縮機、１８は第２冷媒圧縮機であり、蒸発器６から油分離器１１までの構成機器は上記実施例１と同一である（一部図示省略）。
この実施例では、第１吸入配管１５、第２吸入配管１６の液冷媒をそれぞれ気液分離器７に戻すための２つの均液管９を有し、これら均液管９のそれぞれの気液分離器７側近傍を合流部９ａで合流させて、合流均液管９ｂが形成されている。第２の逆止弁１４ａは合流均液管９ｂに設けられており、第１吸入配管１５、第２吸入配管１６から気液分離器７の方向にしか冷媒が流れないように配設されている（図中の矢印が冷媒流通許容方向を示す）。
【００１６】
以上のような構成にすることによって、冷媒圧縮機を、３基，４基，・・・と複数基並列配置した場合でも、合流均液管９ａに第２の逆止弁１４ａを一つ設けるだけで、実施例１と同様の効果を奏し、かつ図３に示すように第１の逆止弁１４を各均液管９の全てに配設したりする必要がないので、装置を安価に製造することができる。
【００１７】
実施例３．
図４はこの発明による実施例３および実施例４を示す冷凍装置の冷媒配管系統図であり、均液管９の途中に逆止弁の代わりに電磁弁１９を設けた場合の実施例を示した図である。図において、２０は冷媒圧縮機１の表面上に取り付けられた温度検知器、１９ａはＣＰＵやメモリ等により実現される制御装置、１９は気液分離器７内に設けられたＵ字管を有する吸入配管８から気液分離器７の方向に流れるような構造を採用しており、かつ、温度検知器２０で検知された温度に基づいて制御装置１９ａにより開閉制御される電磁弁である。その他の構成機器は上記実施例１と同一である。
【００１８】
次に、動作について説明する。冷凍装置の運転中、温度検知器２０が検知した冷媒圧縮機１表面上の温度がある所定温度（例えば、０℃とする）に達した際、０℃未満で電磁弁１９を閉じるようにし、０℃以上では開くようにする。すなわち、冷媒圧縮機１表面上の温度が０℃未満の場合は、液冷媒が均液管９を通って冷媒圧縮機１に吸い込まれているものと判断して、電磁弁１９を閉じ液冷媒が冷媒圧縮機１に吸入されないように制御する。また、冷媒圧縮機１表面上の温度が０℃以上の場合は、液冷媒は冷媒圧縮機１に戻っていないものと判断し、電磁弁１９を開き吸入配管８内の液冷媒を均液管９を通して気液分離器７へ戻すように制御する。以上のような構成でも上記実施例１と同様の効果を奏する。
【００１９】
実施例４．
上記実施例３では、「冷凍装置の運転中」に関する電磁弁１９の制御について説明したが、例えばメインスイッチ（図示省略）の開閉（オン・オフ）状態を検知するスイッチ検知センサ１９ｂを設け、スイッチ検知センサ１９ｂにより検知されたメインスイッチの開閉状態に係る出力から、制御装置１９ａは当該冷凍装置の運転・停止状態を検知し、この運転・停止状態に基づいて電磁弁１９を開閉制御するようにしてもよい。言いかえれば「冷凍装置の停止中」には、電磁弁１９が開くように構成したので、吸入配管８の液冷媒は均液管９を通して気液分離器７へ戻る。従って、長期停止中に液冷媒が冷媒圧縮機１の吸入口１ａより上部まで寝込むことが防止される。以上のような制御においても、上記実施例１と同様の効果を奏する。
すなわち、スイッチ検知センサ１９ｂ、制御装置１９ａ、電磁弁１９を備えてなる構成が、本発明にいう運転状態検知手段の一例である。
【００２０】
実施例５．
図５はこの発明による実施例５を示す冷凍装置の冷媒配管系統図であり、返油管１０の途中に第３の逆止弁１４ｂを設けた例を示した図である。図において、２１，２２はフランジ、２３はフランジ２１とフランジ２２とを固定接続するための連結ボルト、２４は冷媒圧縮機１より送出された高温高圧のガスを油分離器１１へと導く吐出管である。フランジ２１は冷媒圧縮機１に一体的に溶接されており、フランジ２２は吐出管２４に溶接されている。その他の構成機器は実施例１と同一である。
フランジ２１とフランジ２２は連結ボルト２３で締めて固定接続されており、回路内の冷媒が漏れないようになっている。また、開閉弁１２は冷媒圧縮機１と連結ボルト２３で締結されており、回路内の冷媒が漏れることはない（図６参照）。このように連結ボルト２３を用いて接続するのは、市場で冷媒圧縮機１を交換する際の作業性を向上させるためである。
なお、第３の逆止弁１４ｂは油分離器１１から吸入配管８に向かう方向のみへ油が流れるように返油管１０に配設されている（図中の矢印が冷媒流通許容方向を示す）。
油分離器１１で分離された油は、返油管１０、気液分離器７内に設けられたＵ字管を有する吸入配管８を介して冷媒圧縮機１へ戻る。従って、冷媒圧縮機１内の油は通常、所定量確保されている。
【００２１】
そこで、市場において冷媒圧縮機１を交換する場合、まず開閉弁１２，１３を閉め冷媒回路を遮断する。その後、開閉弁１２と冷媒圧縮機１とを接続している連結ボルト２３を外す。さらに吐出側のフランジ２１，２２を接続している連結ボルト２３を外す。この際、開閉弁１２〜開閉弁１３間の回路内の冷媒が放出される。
このとき、吸入配管８と返油管１０との接続口８ｂが開閉弁１２よりも、冷媒流通方向の上流側にあるため、従来の冷媒回路では蒸発器６、気液分離器７内の冷媒が吸入配管８、返油管１０、油分離器１１を経て吐出側から放出されてしまい、冷媒圧縮機１の変換後の真空引きにも時間がかかってしまって、更には大量の冷媒を再度充填しなければならなかった。しかし、返油管１０に第３の逆止弁１４ｂを設けたことにより、吸入配管８から返油管１０、油分離器１１へ流れようとする冷媒を第３の逆止弁１４ｂで遮断することができるので、上記のような問題は解消される。
そして、冷媒圧縮機１を交換し、再び連結ボルト２３で接続し、開閉弁１２と開閉弁１３間を真空引きする。
【００２２】
もし、返油管１０に第３の逆止弁１４ｂが配設されていない構成の場合は、冷媒圧縮機の交換後に真空引きすべき機器内容積が大きくなるため、真空ポンプの容量にもよるが真空引き作業に時間（例えば、２時間程度）がかかり、冷凍装置の運転に支障をきたす場合もあった。また、冷媒圧縮機交換時の冷媒の大量放出にもつながる。
そこで、返油管１０に第３の逆止弁１４ｂを設けたことにより、同規模容量の真空ポンプを用いた真空引き作業がおよそ１時間ですんだ。これにより、市場での冷媒圧縮機１の交換を短時間で確実に実施できるという効果を奏する。
【００２３】
【発明の効果】
以上説明したように、この発明によれば、冷媒回路に複数基の冷媒圧縮機を並列配備した構成であっても、合流均液管を形成しこの合流均液管に第２の逆止弁を配設したので、気液分離器内に設けられたＵ字管を有する各吸入配管からの液冷媒を気液分離器に確実に戻すことができ、気液分離器の液冷媒が各均液管へ短絡して流通し冷媒圧縮機へそのまま吸入されることによる故障を防ぐことができる。そのうえ、第２の逆止弁は少なくとも一つだけで済み、冷媒圧縮機全数分の逆止弁を必要としないので、装置を安価に製造できる。
【００２４】
また、冷媒圧縮機の吸入側の開閉弁と油分離器の冷媒出側の開閉弁とを閉じることにより冷媒回路を遮断した状態で、冷媒圧縮機の取外し・交換を行っても、回路内の冷媒は第３の逆止弁にて油分離器への流出が阻止されるので、返油管を通って油分離器から更に外部へ流出したりしない。そして、冷媒回路の組立復旧後に、冷媒圧縮機および油分離器といった各開閉弁の間の比較的小さな機器内空間を真空引きするだけですむので、市場での冷媒圧縮機の交換サービスを短時間で確実に実施できるという効果を奏する。
【図面の簡単な説明】
【図１】この発明による実施例１を示す冷凍装置の冷媒配管系統図である。
【図２】この発明による実施例２を示す冷凍装置の冷媒配管系統図である。
【図３】この発明による実施例２の比較例となる冷凍装置の冷媒配管系統図である。
【図４】この発明による実施例３および実施例４を示す冷凍装置の冷媒配管系統図である。
【図５】この発明による実施例５を示す冷凍装置の冷媒配管系統図である。
【図６】この発明による実施例５を示す冷凍装置の開閉弁と冷媒圧縮機との接続状態を表した部分外観図である。
【図７】従来の冷凍装置を示す冷媒配管系統図である。
【符号の説明】
１冷媒圧縮機、２凝縮器、５減圧装置、６蒸発器、７気液分離器、８吸入配管、９均液管、９ｂ合流均液管、１０返油管、１１油分離器、１２，１３開閉弁、１４第１の逆止弁、１４ａ第２の逆止弁、１４ｂ第３の逆止弁、１５第１吸入配管、１６第２吸入配管、１７第１冷媒圧縮機、１８第２冷媒圧縮機、１９電磁弁、１９ａ制御装置、１９ｂスイッチ検知センサ、２０温度検知器。[0001]
[Industrial application fields]
The present invention relates to an improvement in reliability of a refrigeration apparatus used in, for example, a low-temperature product case in a supermarket, a refrigerator, a freezer, etc., and an improvement in serviceability in the market.
[0002]
[Prior art]
FIG. 7 is a view showing a refrigerant piping system described in a conventional refrigeration apparatus, for example, the Mitsubishi Electric Cooling and Heating Handbook (1993 edition). In the figure, 1 is a refrigerant compressor, 2 is a condenser, 3 is a liquid reservoir for storing the liquid refrigerant condensed in the condenser 2, 4 is a liquid pipe for sending out the liquid refrigerant in the liquid reservoir 3, and 5 is a pressure reduction. Device, 6 is an evaporator, 7 is a gas-liquid separator, 8 is a suction pipe having a U-shaped pipe connected to the gas-liquid separator 7 and the refrigerant compressor 1 and provided in the gas-liquid separator 7. , 9 is a liquid equalizing pipe communicating from the connection port 8a of the suction pipe 8 to the connection port 7a of the gas-liquid separator 7. A connection port 7 a between the liquid equalizing pipe 9 and the gas-liquid separator 7 is provided at a position below the suction port 1 a of the refrigerant compressor 1.
Subsequently, 10 is an oil return pipe communicating from the oil separator 11 provided in the refrigerant circuit to the suction pipe 8. Reference numerals 12 and 13 denote on-off valves, which are provided for the purpose of shutting down the refrigerant circuit so that it is not necessary to discharge the entire amount of refrigerant in the circuit when the refrigerant compressor 1 is replaced in the market (for example, the shipping destination). It has been. The on-off valve 12 is provided in the refrigerant circuit upstream of the connection port 8 b of the suction pipe 8 communicating with the oil return pipe 10 in the refrigerant flow direction, and the on-off valve 13 is provided between the oil separator 11 and the condenser 2. It has been.
[0003]
A conventional refrigeration apparatus is configured as described above. For example, a high-temperature and high-pressure refrigerant compressed by the refrigerant compressor 1 is separated into a high-temperature and high-pressure gas refrigerant and oil by an oil separator 11. The high-temperature and high-pressure gas refrigerant sent from the oil separator 11 is condensed and liquefied by the condenser 2, and this liquid refrigerant is stored in the liquid reservoir 3. The pressure is reduced by the pressure reducing device 5 for the liquid refrigerant sent from the liquid reservoir 3 through the liquid pipe 4 to be in a gas-liquid two-phase state, and heat is exchanged with the outside air in the evaporator 6 for gasification, and the gas-liquid separator 7, It returns to the refrigerant | coolant compressor 1 again through the suction piping 8, and the above refrigerant cycles are repeated.
[0004]
The oil separated by the oil separator 11 passes through the oil return pipe 10 and returns to the refrigerant compressor 1 through the suction pipe 8 and repeats such an oil cycle. The oil always returns stably so that the refrigerant compressor 1 can operate properly without failure.
Then, the liquid refrigerant that could not be evaporated by the evaporator 6 due to changes in operating conditions and the like is stored in the gas-liquid separator 7, and the gas refrigerant separated here is supplied to the refrigerant compressor 1 via the suction pipe 8. Return and repeat the refrigerant cycle as described above.
Next, when the refrigeration apparatus is stopped for a long time, the refrigerant sleeps with oil as a liquid refrigerant in the refrigerant compressor 1. In order to prevent the liquid refrigerant from sleeping up to the upper part of the refrigerant compressor 1, a large amount of the liquid refrigerant returns to the gas-liquid separator 7 from the suction pipe 8 through the liquid equalizing pipe 9. ing.
[0005]
The oil separated by the oil separator 11 passes through the oil return pipe 10 and returns to the refrigerant compressor 1 through the suction pipe 8. Therefore, it is possible to continue the operation without running out of the oil in the refrigerant compressor 1 at the normal time.
Further, when the refrigerant compressor 1 is replaced in the market, the refrigerant circuit is shut off by closing the on-off valves 12 and 13. At this time, the refrigerant in the circuit has to be slightly released. However, since most of the refrigerant is accommodated in the liquid reservoir 3 or the like, an exchange service can be performed without releasing a large amount of refrigerant. After the refrigerant compressor 1 is replaced and the circuit is restored, the circuit between the on-off valves 12 to 13 on the refrigerant compressor 1 side is evacuated, and the on-off valves 12 and 13 are opened again to operate the refrigeration apparatus. To resume.
[0006]
[Problems to be solved by the invention]
Since the conventional refrigeration apparatus is configured as described above, a large amount of liquid refrigerant is retained in the gas-liquid separator 7 when liquid refrigerant returns to the refrigerant compressor 1 suction side due to changes in operating conditions and the like. However, the liquid refrigerant may be sucked into the refrigerant compressor 1 as it is through the liquid equalizing pipe 9, and the refrigerant compressor 1 may be damaged by the liquid compression of the liquid refrigerant. In order to reliably return the liquid refrigerant to the gas-liquid separator 7, it may be possible to manufacture the gas-liquid separator 7 with a low height. Since the space is occupied, there is a problem that the installation area of the entire apparatus is increased and the cost is increased.
Further, when evacuation is performed from the discharge pipe of the refrigerant compressor 1 at the time of service in the market, the refrigerant in the gas-liquid separator 7 is also drawn through the oil return pipe 10 of the oil separator 11. There was a problem that only the machine 1 could not be evacuated and the evacuation work took a long time.
[0007]
The present invention has been made to solve such a problem, and in order to further improve the reliability of the refrigeration apparatus, the liquid refrigerant in the suction pipe is surely returned to the gas-liquid separator and remains in the liquid refrigerant state. The purpose of this invention is to provide a refrigeration apparatus that can prevent malfunction caused by being sucked into the refrigerant compressor and realize proper operation, and can reliably perform services such as evacuation in the market in a short time.
[0008]
[Means for Solving the Problems]
Refrigeration apparatus according to the present invention, several groups arranged in parallel refrigerant compressor double, a condenser, a pressure reducing device, an evaporator, a gas-liquid separator, and each interposed between the gas-liquid separator and the refrigerant compressor A plurality of suction pipes having U-shaped tubes provided in the gas-liquid separator are sequentially connected to form a refrigerant circuit, and the liquid refrigerant in each suction pipe is connected to the suction pipe and the gas-liquid separator, respectively. A plurality of liquid equalizing pipes for returning the liquid to the gas-liquid separator, and the vicinity of each gas-liquid separator side of the liquid equalizing pipes is joined to form a joined liquid-equalizing pipe. The check valve is arranged with the refrigerant flow permissible direction facing the gas-liquid separator.
[0009]
Further, blocking the configuration described above, an oil separator which is interposed between the condenser and the refrigerant compressor, a refrigerant circuit is provided respectively to the refrigerant outlet side of the suction side and the oil separator of the refrigerant compressor And an oil return pipe that connects the oil separator and the suction pipe. A third check valve is arranged on the oil return pipe with the refrigerant flow permissible direction facing the suction pipe.
[0010]
[Action]
According to the present invention, in the case of a refrigerant circuit in parallel deploying refrigerant compressor of the double number groups, the liquid refrigerant in the suction pipe during normal operation, KakuHitoshieki tube, merging Hitoshieki tube, the second check When the amount of liquid refrigerant in the gas-liquid separator increases while returning to the gas-liquid separator through the valve, the liquid refrigerant in the gas-liquid separator is caused to flow into each liquid equalizing pipe due to the presence of the second check valve. It is prevented from flowing in short circuit. In addition, since at least one second check valve is required and check valves for all the refrigerant compressors are not required, the apparatus can be manufactured at low cost.
[0011]
Further, the on-off valve on the suction side of the refrigerant compressor and the on-off valve on the refrigerant outlet side of the oil separator are closed, whereby the refrigerant circuit is shut off at the position of each on-off valve. At this time, the space in the circuit having a relatively large capacity up to the condenser, the pressure reducing device, the evaporator, the gas-liquid separator, and the suction pipe is sealed with each on-off valve and the third check valve. Therefore, when the refrigerant circuit around the refrigerant compressor and the oil separator is disassembled, a small amount of refrigerant flows out to the outside. After the refrigerant compressor is replaced and the refrigerant circuit is assembled and restored, it is only necessary to evacuate a relatively small internal space between the on-off valves such as the refrigerant compressor and the oil separator.
[0012]
【Example】
Example 1.
FIG. 1 is a refrigerant piping system diagram of a refrigeration apparatus showing Embodiment 1 according to the present invention. Since 1 to 13 are the same as those of a conventional apparatus, their detailed description is omitted. In the figure, reference numeral 14 denotes a first check valve provided in the middle of the liquid equalizing pipe 9. In this case, the gas-liquid is supplied from the suction pipe 8 having a U-shaped pipe provided in the gas-liquid separator 7. It is arranged so that the refrigerant flows only in the direction toward the separator 7 (the arrow in the figure indicates the refrigerant flow allowable direction).
[0013]
In the refrigeration apparatus configured as in this embodiment, for example, high-temperature and high-pressure refrigerant compressed by the refrigerant compressor 1 is separated into high-temperature and high-pressure gas refrigerant and oil by the oil separator 11. The high-temperature and high-pressure gas refrigerant sent from the oil separator 11 is condensed and liquefied by the condenser 2, and the liquid refrigerant is stored in the liquid reservoir 3. The liquid refrigerant sent from the liquid reservoir 3 through the liquid pipe 4 is decompressed by the decompression device 5 to be in a gas-liquid two-phase state, and is gasified by exchanging heat with the outside air in the evaporator 6. The refrigerant cycle is repeated by returning to the refrigerant compressor 1 through the suction pipe 8.
Further, the oil separated by the oil separator 11 passes through the oil return pipe 10 and returns to the refrigerant compressor 1 through the suction pipe 8 and repeats the oil cycle as described above. In addition, oil always returns stably so that proper operation can be performed without failure of the refrigerant compressor 1.
[0014]
Further, the liquid refrigerant that could not be evaporated by the evaporator 6 due to changes in operating conditions and the like is stored in the gas-liquid separator 7, and the gas refrigerant separated here is supplied to the refrigerant compressor 1 via the suction pipe 8. Return and repeat the refrigerant cycle as described above.
Further, when the liquid refrigerant returns to the refrigerant compressor 1 due to a change in operating conditions or the like, the liquid refrigerant in the gas-liquid separator 7 tends to flow into the refrigerant compressor 1 through the liquid equalizing pipe 9, but the liquid equalizing Since the first check valve 14 is attached to the pipe 9, the liquid refrigerant in the gas-liquid separator 7 is prevented from flowing toward the refrigerant compressor 1 as it is. Therefore, failure (damage due to liquid compression) due to liquid refrigerant suction of the refrigerant compressor 1 can be prevented. Further, the liquid refrigerant in the suction pipe 8 returns to the gas-liquid separator 7 through the liquid equalizing pipe 9 so that the liquid refrigerant does not fall into the upper part of the refrigerant compressor 1 when the liquid refrigerant falls into the refrigerant compressor 1 during the long-term stoppage. be able to.
[0015]
Example 2
FIG. 2 is a refrigerant piping system diagram of a refrigeration apparatus showing Embodiment 2 according to the present invention, and is a diagram showing a configuration in which two refrigerant compressors are arranged in parallel. In the figure, 15 is a first suction pipe having a U-shaped pipe provided in the gas-liquid separator 7 , 16 is a second suction pipe having a U-shaped pipe provided in the gas-liquid separator 7, and 17 is a first suction pipe. 1 refrigerant compressor, 18 is a 2nd refrigerant compressor, and the components from the evaporator 6 to the oil separator 11 are the same as that of the said Example 1 (some illustration is omitted).
In this embodiment, there are two liquid leveling pipes 9 for returning the liquid refrigerant in the first suction pipe 15 and the second suction pipe 16 to the gas-liquid separator 7, respectively. The vicinity of the separator 7 is merged at the merging portion 9a to form a merging and soaking tube 9b. The second check valve 14 a is provided in the merging and liquid equalizing pipe 9 b and is arranged so that the refrigerant flows only from the first suction pipe 15 and the second suction pipe 16 to the gas-liquid separator 7. (The arrow in the figure indicates the refrigerant flow allowable direction).
[0016]
With the configuration as described above, even when a plurality of refrigerant compressors are arranged in parallel with three, four,..., One second check valve 14a is provided in the merging / equalizing and equalizing pipe 9a. Thus, the same effect as that of the first embodiment is obtained, and it is not necessary to dispose the first check valves 14 in all the liquid equalizing pipes 9 as shown in FIG. Can be manufactured.
[0017]
Example 3 FIG.
FIG. 4 is a refrigerant piping system diagram of a refrigeration apparatus showing Embodiments 3 and 4 according to the present invention, showing an embodiment in which an electromagnetic valve 19 is provided in the middle of the liquid equalizing pipe 9 instead of a check valve. It is a figure. In the figure, 20 is a temperature detector mounted on the surface of the refrigerant compressor 1, 19a is a control device realized by a CPU, memory, etc., and 19 has a U-shaped tube provided in the gas-liquid separator 7. It is a solenoid valve that employs a structure that flows from the suction pipe 8 toward the gas-liquid separator 7 and that is controlled to open and close by the control device 19 a based on the temperature detected by the temperature detector 20. Other components are the same as those in the first embodiment.
[0018]
Next, the operation will be described. During operation of the refrigeration system, when the temperature on the surface of the refrigerant compressor 1 detected by the temperature detector 20 reaches a certain temperature (for example, 0 ° C.), the solenoid valve 19 is closed at less than 0 ° C., Open above 0 ° C. That is, when the temperature on the surface of the refrigerant compressor 1 is lower than 0 ° C., it is determined that the liquid refrigerant is sucked into the refrigerant compressor 1 through the liquid equalizing pipe 9, and the electromagnetic valve 19 is closed and the liquid refrigerant is closed. Is controlled so as not to be sucked into the refrigerant compressor 1. If the temperature on the surface of the refrigerant compressor 1 is 0 ° C. or higher, it is determined that the liquid refrigerant has not returned to the refrigerant compressor 1, and the electromagnetic valve 19 is opened and the liquid refrigerant in the suction pipe 8 is liquefied. 9 is controlled to return to the gas-liquid separator 7. Even with the configuration as described above, the same effects as those of the first embodiment can be obtained.
[0019]
Example 4
In the third embodiment, the control of the solenoid valve 19 related to “during operation of the refrigeration apparatus” has been described. From the output related to the open / close state of the main switch detected by the detection sensor 19b, the control device 19a detects the operation / stop state of the refrigeration apparatus and controls the opening / closing of the solenoid valve 19 based on the operation / stop state. May be. In other words, since the solenoid valve 19 is configured to open while “the refrigeration apparatus is stopped”, the liquid refrigerant in the suction pipe 8 returns to the gas-liquid separator 7 through the liquid equalizing pipe 9. Therefore, the liquid refrigerant is prevented from sleeping up to the upper part from the inlet 1a of the refrigerant compressor 1 during the long-term stop. Even in the control as described above, the same effects as those of the first embodiment are obtained.
That is, the configuration including the switch detection sensor 19b, the control device 19a, and the electromagnetic valve 19 is an example of the operation state detection means in the present invention.
[0020]
Embodiment 5 FIG.
FIG. 5 is a refrigerant piping system diagram of a refrigeration apparatus showing Embodiment 5 according to the present invention, and is a diagram showing an example in which a third check valve 14 b is provided in the middle of the oil return pipe 10. In the figure, 21 and 22 are flanges, 23 is a connecting bolt for fixedly connecting the flange 21 and the flange 22, and 24 is a discharge pipe for guiding the high-temperature and high-pressure gas sent from the refrigerant compressor 1 to the oil separator 11. It is. The flange 21 is integrally welded to the refrigerant compressor 1, and the flange 22 is welded to the discharge pipe 24. Other components are the same as those in the first embodiment.
The flange 21 and the flange 22 are fixedly connected by fastening with a connecting bolt 23 so that the refrigerant in the circuit does not leak. Moreover, the on-off valve 12 is fastened by the refrigerant compressor 1 and the connecting bolt 23, so that the refrigerant in the circuit does not leak (see FIG. 6). The connection using the connecting bolt 23 is to improve workability when replacing the refrigerant compressor 1 in the market.
The third check valve 14b is arranged in the oil return pipe 10 so that oil flows only in the direction from the oil separator 11 to the suction pipe 8 (the arrow in the figure indicates the refrigerant flow allowable direction). .
The oil separated by the oil separator 11 returns to the refrigerant compressor 1 through the oil return pipe 10 and the suction pipe 8 having a U-shaped pipe provided in the gas-liquid separator 7 . Therefore, a predetermined amount of oil in the refrigerant compressor 1 is usually secured.
[0021]
Therefore, when replacing the refrigerant compressor 1 in the market, the on-off valves 12 and 13 are first closed to shut off the refrigerant circuit. Thereafter, the connecting bolt 23 connecting the on-off valve 12 and the refrigerant compressor 1 is removed. Further, the connecting bolt 23 connecting the discharge side flanges 21 and 22 is removed. At this time, the refrigerant in the circuit between the on-off valve 12 and the on-off valve 13 is released.
At this time, since the connection port 8b between the suction pipe 8 and the oil return pipe 10 is located upstream of the on-off valve 12 in the refrigerant flow direction, the refrigerant in the evaporator 6 and the gas-liquid separator 7 is not used in the conventional refrigerant circuit. It is discharged from the discharge side through the suction pipe 8, the oil return pipe 10, and the oil separator 11, and it takes time for evacuation after conversion of the refrigerant compressor 1. Further, a large amount of refrigerant is refilled again. I had to. However, by providing the third check valve 14b in the return oil pipe 10, the third check valve 14b can block the refrigerant that flows from the suction pipe 8 to the return oil pipe 10 and the oil separator 11. Since this is possible, the above problems are solved.
And the refrigerant compressor 1 is replaced | exchanged and it connects again with the connection bolt 23, and the vacuum between the on-off valve 12 and the on-off valve 13 is evacuated.
[0022]
If the oil return pipe 10 is not provided with the third check valve 14b, the internal volume of the equipment to be evacuated after replacement of the refrigerant compressor becomes large, depending on the capacity of the vacuum pump. The evacuation operation takes time (for example, about 2 hours), which sometimes hinders the operation of the refrigeration apparatus. In addition, a large amount of refrigerant is released when the refrigerant compressor is replaced.
Therefore, by providing the third check valve 14b in the oil return pipe 10, the vacuuming operation using a vacuum pump of the same scale capacity is about one hour. Thereby, there exists an effect that replacement | exchange of the refrigerant compressor 1 in a market can be implemented reliably in a short time.
[0023]
【The invention's effect】
As described above, according to the present invention, even in parallel deployed configuration the refrigerant compressor of the plurality groups refrigerant circuit, forms a confluent equalizing liquid pipe second check in the merged Hitoshieki tube Since the valve is provided , the liquid refrigerant from each suction pipe having a U-shaped tube provided in the gas-liquid separator can be reliably returned to the gas-liquid separator, and the liquid refrigerant in the gas-liquid separator It is possible to prevent a failure caused by short-circuiting to the liquid equalizing pipe and flowing into the refrigerant compressor as it is. In addition, since at least one second check valve is required and check valves for all the refrigerant compressors are not required, the apparatus can be manufactured at low cost.
[0024]
Even if the refrigerant compressor is removed or replaced while the refrigerant circuit is shut off by closing the on-off valve on the suction side of the refrigerant compressor and the on-off valve on the refrigerant outlet side of the oil separator, Since the refrigerant is prevented from flowing out to the oil separator by the third check valve, it does not flow further out from the oil separator through the oil return pipe. After assembly and restoration of the refrigerant circuit, it is only necessary to evacuate the relatively small equipment space between the on-off valves such as the refrigerant compressor and oil separator. The effect is that it can be carried out reliably.
[Brief description of the drawings]
FIG. 1 is a refrigerant piping system diagram of a refrigeration apparatus showing Embodiment 1 according to the present invention.
FIG. 2 is a refrigerant piping system diagram of a refrigeration apparatus showing Embodiment 2 according to the present invention.
FIG. 3 is a refrigerant piping system diagram of a refrigeration apparatus as a comparative example of Embodiment 2 according to the present invention.
FIG. 4 is a refrigerant piping system diagram of a refrigeration apparatus showing Embodiment 3 and Embodiment 4 according to the present invention.
FIG. 5 is a refrigerant piping system diagram of a refrigeration apparatus showing Embodiment 5 according to the present invention.
FIG. 6 is a partial external view showing a connection state between an on-off valve and a refrigerant compressor of a refrigeration apparatus showing Embodiment 5 according to the present invention.
FIG. 7 is a refrigerant piping system diagram showing a conventional refrigeration apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Refrigerant compressor, 2 Condenser, 5 Pressure reduction apparatus, 6 Evaporator, 7 Gas-liquid separator, 8 Intake pipe, 9 Liquid equalizing pipe, 9b Merged liquid equalizing pipe, 10 Oil return pipe, 11 Oil separator, 12, 13 On-off valve, 14 first check valve, 14a second check valve, 14b third check valve, 15 first suction pipe, 16 second suction pipe, 17 first refrigerant compressor, 18 second refrigerant Compressor, 19 solenoid valve, 19a control device, 19b switch detection sensor, 20 temperature detector.

Claims

A plurality of refrigerant compressors, condensers, pressure reducing devices, evaporators, gas-liquid separators, and gas-liquid separators interposed between the gas-liquid separator and the refrigerant compressor, respectively . A refrigerant circuit is configured by sequentially connecting a plurality of suction pipes having U-shaped tubes provided therein, and the liquid refrigerant in each suction pipe is connected to the suction pipe and the gas-liquid separator, respectively. A plurality of liquid equalization pipes for returning to the separator, and a gas-liquid separator side vicinity of each of the liquid equalization pipes is merged to form a merge liquid equalization pipe; A refrigeration apparatus, wherein a stop valve is arranged with the refrigerant flow permissible direction facing the gas-liquid separator.

An oil separator interposed between the refrigerant compressor and the condenser, and an on-off valve provided on each of the suction side of the refrigerant compressor and the refrigerant outlet side of the oil separator and capable of shutting off the refrigerant circuit; An oil return pipe that connects the oil separator and the suction pipe, and a third check valve is disposed in the oil return pipe with the refrigerant flow permissible direction facing the suction pipe. The refrigeration apparatus according to 1.