JP3606943B2

JP3606943B2 - refrigerator

Info

Publication number: JP3606943B2
Application number: JP09332295A
Authority: JP
Inventors: 明兵藤
Original assignee: 松下冷機株式会社
Priority date: 1995-04-19
Filing date: 1995-04-19
Publication date: 2005-01-05
Anticipated expiration: 2020-01-05
Also published as: JPH08285414A

Description

【０００１】
【産業上の利用分野】
本発明は、冷蔵庫に関し、特に除霜後の圧縮機起動の過渡運転時に生じる低圧運転防止に関する。
【０００２】
【従来の技術】
従来の冷蔵庫は、実開平３−８３７９１号公報にて知られるような構成を持っている。以下、図７を参考に従来の冷蔵庫の構成について説明を行う。
【０００３】
１は高圧容器型の圧縮機、２は凝縮器、３は減圧装置である毛細管、４は蒸発器であり、圧縮機１、凝縮器２、毛細管３、蒸発器４は順次環状に接続し、冷凍サイクルを形成している。５は冷蔵庫の本体で内部を区画し、それぞれ冷凍室６と冷蔵室７の２室を形成している。８は除霜用ヒータで、蒸発器４の近傍に設けてある。
【０００４】
９は除霜検知手段であらかじめ設定した時間間隔や、蒸発器４の温度、着霜状態を検知し、また除霜運転時には、除霜の終了を検知する。除霜検知手段９の検知出力により図示しない除霜制御手段で、圧縮機１の運転、停止、除霜用ヒータ８の運転停止を制御する。
【０００５】
１０は除霜水を蒸発皿１１に導く水パイプであり、蒸発皿１１は機械室１２内にあって凝縮器２の一部を蒸発皿１１に配設してある。凝縮器２の一部は蒸発の効率向上のため圧縮機１の吐出に近い部分が通常使われる。
【０００６】
次に上記従来の構成の動作について説明する。
圧縮機１の運転により、圧縮機１より吐出された高温高圧の冷媒は、凝縮器２により凝縮液化し、さらに、毛細管３にて減圧され、蒸発器４で蒸発気化し図示しない熱搬送手段により冷凍室６、冷蔵室７を冷却する。蒸発器４で気化した冷媒は、再び、圧縮機１に吸入される。
【０００７】
この様な冷却運転を行うことにより、冷凍室６、冷蔵室７内の空気に含まれる水分が、蒸発器４で熱交換される際に霜として、蒸発器４の表面に付着する。この着霜が進むと、蒸発器４の熱交換効率が減少し、充分な冷却運転が不可能となってくる。
【０００８】
この状態を除霜検知手段９が検知し、除霜制御手段に除霜開始信号を出力する。この信号を受け除霜検知手段は、除霜を開始する。
【０００９】
除霜制御手段は、圧縮機１を停止し除霜用ヒータ８を運転し、除霜を開始する。除霜用ヒータ８の運転により、蒸発器４の表面の霜を発熱により融解する。
【００１０】
蒸発器４の表面の霜が融解すると、除霜検知手段９は除霜が完了したことを通常蒸発器４の温度が所定温度（一般的には１０から２０℃）以上になることで検知し、除霜制御手段へ除霜終了信号を出力する。除霜制御手段はこの信号を受けて、除霜運転を終了するため、除霜用ヒータ８を停止し、その後、圧縮機１を起動する。この操作により冷凍サイクルは再び冷却運転を開始する。
【００１１】
除霜により発生する除霜水は水パイプ１０を通じて蒸発皿１１へと送られる。蒸発皿に一旦貯留された除霜水は圧縮機１が運転を始めると高温の凝縮器２の一部分と熱交換することで徐々に蒸発していく。
【００１２】
【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、低周囲温度時において、除霜開始直前に蒸発器４内に保持される冷媒に加え、圧縮機１停止と同時に、凝縮器２及び圧縮機１の周囲温度と蒸発器４の周囲温度の差から生じる冷媒の飽和圧力差により、圧縮機１、凝縮器２から蒸発器４へ冷媒が移動を始める。
【００１３】
そして、除霜の進行により蒸発器４の温度が上昇し、圧縮機１、凝縮器２の周囲温度より蒸発器４及びその周囲温度が高くなると、除霜運転初期とは逆に、冷媒の飽和圧力が蒸発器４内の方が高くなり、冷媒は蒸発器４から圧縮機１、凝縮器２へと移動を行う。
【００１４】
除霜終了時においては蒸発器４内の冷媒はほとんどなくなり、冷凍サイクル中最も温度の低い凝縮器２内で遍在して滞留する。特に低温の除霜水により冷却される凝縮器の一部等に遍在する。
【００１５】
このため、除霜後の圧縮機１起動時には、通常の運転安定状態における凝縮器２内の冷媒分布状態、つまり圧縮機１から毛細管３方向へと気相から液相へといった状態でなく冷媒が滞留し、かつ蒸発器４内にほとんど冷媒がない。
【００１６】
このため、圧縮機１が起動すると蒸発器４内にほとんど冷媒が存在しないので吸込みガスの比体積は小さく、十分に加圧する事ができない。と同時に凝縮器２内で冷媒が遍在しているので、安定して毛細管３入口部に液冷媒が到達せず、毛細管３に多量のガスが噛み込み、冷媒の循環を阻害する。
【００１７】
この悪循環によって、除霜後の運転過渡期における冷凍サイクルのバランスが崩れた低圧運転状態が起こる。
【００１８】
起動過渡期に液戻り等により圧縮機１の摺動部の油膜が切れた状態でさらに冷媒も、冷媒とともに巡回している潤滑油も少ししか戻ってこない低圧運転が続く圧縮機１の摺動部は乾燥摩擦となり異常磨耗が発生し圧縮機１の信頼性の面から非常に大きな課題であった。
【００１９】
さらに、起動後冷凍サイクルが安定するまで時間がかかり、運転時間の増加から、消費電力の増加につながる。
【００２０】
本発明の冷蔵庫は従来の課題を解決するもので、除霜後の圧縮機起動時における低圧運転を防止できる冷蔵庫を提供することを目的とする。
【００２１】
【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の冷蔵庫は、圧縮機と、凝縮器と、毛細管と、蒸発器とを順次環状に接続してなる冷凍サイクルを設置し、前記蒸発器近傍に除霜用ヒータと、前記凝縮器と前記蒸発器入口部との間に絞りを有するバイパス回路と、前記凝縮器と前記バイパス回路との接続部に配設した冷媒の流れを制御する開閉弁と、前記開閉弁の開閉タイミング検知手段と、前記開閉弁の開閉を行う開閉弁制御手段とを備え、開閉タイミング検知手段が蒸発器近傍に設けた除霜検知手段であり、開閉弁制御手段がタイマーを有し、前記除霜検知手段が除霜終了を検知した時に、除霜終了後の圧縮機起動過渡期に冷媒とともに潤滑油の戻りを促進するために前記開閉弁を開放し、前記タイマーが所定の時間を経過した時に前記開閉弁を閉鎖する開閉弁制御手段とを備えるものである。
【００２５】
【作用】
上記構成により、本発明の冷蔵庫は、電磁弁開閉タイミング検知手段である除霜検知手段が除霜終了を検知すると、電磁弁制御手段によって信号が送られ、電磁弁が開放される。高圧容器型圧縮機が起動すると、前記凝縮器から前記蒸発器入口部へ直接冷媒が循環し、蒸発圧力が上昇するので吸入圧力も上昇し、さらには高圧圧力が上昇する。
【００２６】
高圧圧力の上昇によって冷媒の循環が促進され、冷凍サイクルのバランスの崩れた状態が修正される。
【００２７】
前記開閉弁制御手段が有するタイマーが所定時間を経過すると前記開閉弁が閉鎖されるので、低圧運転が起こらず安定状態への移行がスムーズに行える。
【００３３】
【実施例】
本発明による冷蔵庫の一実施例について図１〜図６を参考に説明する。但し、従来と同一構成については、同一の符号を付し、詳細な説明を省略する。
【００３４】
１は高圧容器型の圧縮機、２は凝縮器、３は毛細管、４は蒸発器であり、圧縮機１、凝縮器２、毛細管３、蒸発器４は順次環状に接続し、冷凍サイクルを形成している。
【００３５】
１３は絞り１４を有するバイパス回路であり、凝縮器２と、蒸発器４の入口部とを接続してなる。バイパス回路１３と凝縮器２の接続部に電磁弁１５を設けてある。１６はタイマー１７を有する電磁弁制御手段であり、１８は電磁弁の開閉タイミング検知手段である吸入圧力検知手段である。
【００３６】
５は冷蔵庫の本体で内部を区画し、それぞれ少なくとも１室の冷凍室６と少なくとも１室の冷蔵室７により少なくとも２室を形成している。８は除霜用ヒータで、蒸発器４の近傍に設けてある。
【００３７】
９は除霜検知手段であらかじめ設定した時間間隔や、蒸発器４の温度、着霜状態を検知し、また除霜運転時には、除霜の終了を検知する。除霜検知手段９の検知出力により図示しない除霜制御手段で、圧縮機１の運転、停止、除霜用ヒータ８の運転停止を制御する。
【００３８】
次に上記従来の構成の動作について説明する。
圧縮機１の運転による冷却運転が行われ、蒸発器４で着霜が進む。これにより、蒸発器４の熱交換効率が減少し、充分な冷却運転が不可能となってくる。
【００３９】
この状態を除霜検知手段９が検知し、除霜制御手段に除霜開始信号を出力する。この信号を受け除霜検知手段は、除霜を開始する。
【００４０】
除霜制御手段は、圧縮機１を停止し除霜用ヒータ８を運転し、除霜を開始する。除霜用ヒータ８の運転により、蒸発器４の表面の霜を発熱により融解する。
【００４１】
蒸発器４の表面の霜が融解すると、除霜検知手段９は除霜が完了したことを通常蒸発器４の温度が所定温度（一般的には１０から２０℃）以上になることで検知し、除霜制御手段へ除霜終了信号を出力する。除霜制御手段はこの信号を受けて、除霜運転を終了するため、除霜用ヒータ８を停止し、その後、圧縮機１を起動する。この操作により冷凍サイクルは再び冷却運転を開始する。
【００４２】
低周囲温度時において、除霜中に蒸発器４の温度が上昇し、圧縮機１、凝縮器２の周囲温度より蒸発器４及びその周囲温度が高くなると、冷媒の飽和圧力が蒸発器４内の方が高くなり、冷媒は蒸発器４から圧縮機１、凝縮器２へと移動を行う。
【００４３】
除霜終了時においては蒸発器４内の冷媒はほとんどなくなり、冷凍サイクル中最も温度の低い凝縮器２内で遍在して滞留する。
【００４４】
このため、除霜後の圧縮機１起動時には、通常の運転安定状態における凝縮器２内の冷媒分布状態、つまり圧縮機１から毛細管３方向へと気相から液相へといった状態でなく冷媒が滞留し、かつ蒸発器４内にほとんど冷媒が存在しないので吸込みガスの比体積は小さく、十分に加圧する事ができない。
【００４５】
同時に凝縮器２内で冷媒が遍在しているので、安定して毛細管３入口部に液冷媒が到達せず、毛細管３に多量のガスが噛み込み、冷媒の循環を阻害する。これにより圧縮機１の吸入圧力が低下する。
【００４６】
図２に示すように、ステップ１で吸入圧力検知手段１８により検知された圧力値が電磁弁制御手段１６に入力され、ステップ２で検知圧力値が所定の圧力以下であるならば、ステップ３へ進みタイマー１７をスタートさせ、高い場合はステップ１へと戻る。
【００４７】
ステップ３でタイマー１７をスタートさせた後、ステップ４で電磁弁１５を開放する。そしてステップ５でタイマー１７がカウントアップしているか調べ、カウントアップしていなければステップ４へ戻り、カウントアップしていればステップ６へ進み電磁弁１５を閉鎖する。
【００４８】
こうして圧縮機１の吸入圧力が低下すると、バイバス回路１３が開放されて、凝縮器２内に偏在して存在する冷媒が絞り１４を経て、蒸発器４の入口部へ吸入され、蒸発圧力が絞り１４の絞り量に応じて上昇し、吸入圧力も上昇するので高圧圧力も同時に上昇する。
【００４９】
電磁弁１５が閉鎖されバイパス回路１３が遮断されると、高圧圧力の上昇により、冷媒の循環が促進され、冷凍サイクルのバランスの崩れた状態が修正される。
【００５０】
起動過渡期に低圧運転がないので、冷媒とともに巡回している潤滑油が戻ってくるので圧縮機１の摺動部は乾燥摩擦とはならないので圧縮機１の摺動部異常磨耗が発生することなく圧縮機１の信頼性を確保することができる。
【００５１】
さらに、除霜後の起動後に、冷凍サイクルが速やかに安定するので、運転時間が短縮され、消費電力の低減となる。
【００５２】
また、図３、図４に示すように、電磁弁の開閉タイミング検知手段である吸入圧力検知手段１８の代わりに除霜検知手段９を用いて、ステップ１で除霜検知手段９から除霜終了の信号を取り込み、ステップ２で除霜が終了したならステップ３へ進み、未終了であるならステップ１へ戻る電磁弁制御手段１６であっても良い。
【００５３】
これにより圧力検知手段分の低コスト化が図れる。
さらに、また、図５、図６に示すように、電磁弁の開閉タイミング検知手段である吸入圧力検知手段１８の代わりに毛細管３と蒸発器４との接続部に設けた温度検知手段１９を用いて、ステップ１で例えばサーミスタである温度検知手段１９から配管温度を取り込み、ステップ２で検知温度値が所定の温度以下であるならば、ステップ３へ進みタイマー１７をスタートさせ、高い場合はステップ１へと戻る電磁弁制御手段１６であっても良い。
【００５４】
なお、温度検知手段１９はバイメタルであっても同様の効果が得られる。
なお、電磁弁１５は通電により閉鎖、停電により開放としても良いし、逆でもよいが、望ましくは大部分の時間をしめる通常の冷蔵庫運転時には閉鎖状態であるため電力消費量が低減できるため、通電により開放がよい。また、通電により開放状態と閉鎖状態を切り替えるもので有ればなお良い。
【００５５】
【発明の効果】
以上の説明から明らかなように本発明の冷蔵庫は、圧縮機と、凝縮器と、毛細管と、蒸発器とを順次環状に接続してなる冷凍サイクルを設置し、前記蒸発器近傍に除霜用ヒータと、前記凝縮器と前記蒸発器入口部との間に絞りを有するバイパス回路と、前記凝縮器と前記バイパス回路との接続部に配設した冷媒の流れを制御する開閉弁と、前記開閉弁の開閉タイミング検知手段と、前記開閉弁の開閉を行う開閉弁制御手段とを備え、開閉タイミング検知手段が蒸発器近傍に設けた除霜検知手段であり、開閉弁制御手段がタイマーを有し、前記除霜検知手段が除霜終了を検知した時に、除霜終了後の圧縮機起動過渡期に冷媒とともに潤滑油の戻りを促進するために前記開閉弁を開放し、前記タイマーが所定の時間を経過した時に前記開閉弁を閉鎖する開閉弁制御手段とを備えたので、除霜後に前記バイパス回路が開放され、所定時間経過後前記バイパス回路が閉鎖されるので低圧運転が起こらない。
【００５９】
以上のように起動過渡期に低圧運転が起こらないので、冷媒とともに巡回している潤滑油がすぐに戻り、前記高圧容器型圧縮機の摺動部は乾燥摩擦とはならないので、前記高圧容器型圧縮機の摺動部異常磨耗が発生することなく前記高圧容器型圧縮機の信頼性を確保することができる。
【００６０】
さらに、起動後前記冷凍サイクルのバランスの崩れた状態が続かないので、前記高圧容器型圧縮機の運転時間が短縮され、消費電力の低減となる。
【図面の簡単な説明】
【図１】本発明による冷蔵庫の一実施例の断面図
【図２】本発明による冷蔵庫の一実施例の電磁弁の動作を示すフローチャート
【図３】本発明による冷蔵庫の一実施例の断面図
【図４】本発明による冷蔵庫の一実施例の電磁弁の動作を示すフローチャート
【図５】本発明による冷蔵庫の一実施例の断面図
【図６】本発明による冷蔵庫の一実施例の電磁弁の動作を示すフローチャート
【図７】従来の冷蔵庫の断面図
【符号の説明】
１圧縮機
２凝縮器
３毛細管
４蒸発器
８除霜用ヒータ
９除霜検知手段
１３バイパス回路
１５電磁弁
１６電磁弁制御手段
１７タイマー
１８吸入圧力検知手段
１９温度検知手段[0001]
[Industrial application fields]
The present invention relates to a refrigerator, and more particularly to prevention of low-pressure operation that occurs during transient operation of starting a compressor after defrosting.
[0002]
[Prior art]
The conventional refrigerator has a structure as known in Japanese Utility Model Laid-Open No. 3-83791. Hereinafter, the configuration of a conventional refrigerator will be described with reference to FIG.
[0003]
1 is a high-pressure vessel type compressor, 2 is a condenser, 3 is a capillary tube as a decompression device, 4 is an evaporator, and the compressor 1, the condenser 2, the capillary tube 3, and the evaporator 4 are sequentially connected in an annular shape, A refrigeration cycle is formed. Reference numeral 5 denotes a main body of the refrigerator, which divides the inside and forms two rooms, a freezer compartment 6 and a refrigerator compartment 7, respectively. A defrosting heater 8 is provided in the vicinity of the evaporator 4.
[0004]
9 detects the time interval set in advance by the defrosting detecting means, the temperature of the evaporator 4 and the frosting state, and detects the end of defrosting during the defrosting operation. The defrost control means (not shown) controls the operation and stop of the compressor 1 and the operation stop of the defrost heater 8 by the detection output of the defrost detection means 9.
[0005]
Reference numeral 10 denotes a water pipe that guides the defrost water to the evaporating dish 11. The evaporating dish 11 is in the machine chamber 12, and a part of the condenser 2 is disposed in the evaporating dish 11. A part near the discharge of the compressor 1 is usually used as a part of the condenser 2 in order to improve the evaporation efficiency.
[0006]
Next, the operation of the conventional configuration will be described.
The high-temperature and high-pressure refrigerant discharged from the compressor 1 by the operation of the compressor 1 is condensed and liquefied by the condenser 2, further depressurized by the capillary 3, evaporated by the evaporator 4, and heated by heat transfer means (not shown). The freezer compartment 6 and the refrigerator compartment 7 are cooled. The refrigerant vaporized by the evaporator 4 is again sucked into the compressor 1.
[0007]
By performing such a cooling operation, moisture contained in the air in the freezer compartment 6 and the refrigerator compartment 7 adheres to the surface of the evaporator 4 as frost when heat is exchanged in the evaporator 4. As this frosting progresses, the heat exchange efficiency of the evaporator 4 decreases, and sufficient cooling operation becomes impossible.
[0008]
This state is detected by the defrost detection means 9 and outputs a defrost start signal to the defrost control means. Upon receiving this signal, the defrost detection means starts defrosting.
[0009]
The defrosting control means stops the compressor 1, operates the defrosting heater 8, and starts defrosting. By operating the defrosting heater 8, the frost on the surface of the evaporator 4 is melted by heat generation.
[0010]
When the frost on the surface of the evaporator 4 is melted, the defrosting detecting means 9 detects that the defrosting is completed when the temperature of the normal evaporator 4 is equal to or higher than a predetermined temperature (generally 10 to 20 ° C.). The defrosting end signal is output to the defrosting control means. In response to this signal, the defrosting control means stops the defrosting heater 8 in order to end the defrosting operation, and then starts the compressor 1. By this operation, the refrigeration cycle starts the cooling operation again.
[0011]
The defrost water generated by the defrosting is sent to the evaporating dish 11 through the water pipe 10. The defrost water once stored in the evaporating dish is gradually evaporated by exchanging heat with a part of the high-temperature condenser 2 when the compressor 1 starts operation.
[0012]
[Problems to be solved by the invention]
However, in the above conventional configuration, at the low ambient temperature, in addition to the refrigerant held in the evaporator 4 immediately before the start of defrosting, at the same time as the compressor 1 is stopped, the ambient temperature of the condenser 2 and the compressor 1 and the evaporator The refrigerant starts to move from the compressor 1 and the condenser 2 to the evaporator 4 due to the refrigerant saturation pressure difference resulting from the difference in the ambient temperature of 4.
[0013]
When the temperature of the evaporator 4 rises due to the progress of defrosting, and the evaporator 4 and its ambient temperature become higher than the ambient temperature of the compressor 1 and the condenser 2, the refrigerant is saturated, contrary to the initial stage of the defrosting operation. The pressure is higher in the evaporator 4, and the refrigerant moves from the evaporator 4 to the compressor 1 and the condenser 2.
[0014]
At the end of defrosting, the refrigerant in the evaporator 4 almost disappears and remains ubiquitously in the condenser 2 having the lowest temperature during the refrigeration cycle. In particular, it is ubiquitous in some condensers cooled by low-temperature defrost water.
[0015]
For this reason, at the time of starting the compressor 1 after defrosting, the refrigerant is not the refrigerant distribution state in the condenser 2 in the normal operation stable state, that is, the state from the gas phase to the liquid phase from the compressor 1 toward the capillary 3. It stays and there is almost no refrigerant in the evaporator 4.
[0016]
For this reason, when the compressor 1 is started, since there is almost no refrigerant in the evaporator 4, the specific volume of the suction gas is small and it cannot be pressurized sufficiently. At the same time, since the refrigerant is ubiquitous in the condenser 2, the liquid refrigerant does not reach the inlet of the capillary tube 3 stably, and a large amount of gas is caught in the capillary tube 3, thereby inhibiting the circulation of the refrigerant.
[0017]
Due to this vicious cycle, a low-pressure operation state occurs in which the balance of the refrigeration cycle is lost in the operation transition period after defrosting.
[0018]
The sliding of the compressor 1 continues in a low pressure operation in which the refrigerant and the lubricating oil circulating with the refrigerant return little while the oil film of the sliding portion of the compressor 1 is cut off due to liquid return or the like in the startup transition period. The part became dry friction and abnormal wear occurred, which was a very big problem from the viewpoint of the reliability of the compressor 1.
[0019]
Furthermore, it takes time until the refrigeration cycle is stabilized after startup, leading to an increase in power consumption due to an increase in operating time.
[0020]
The refrigerator of this invention solves the conventional subject, and it aims at providing the refrigerator which can prevent the low voltage | pressure operation at the time of the compressor starting after a defrost.
[0021]
[Means for Solving the Problems]
In order to achieve this object, the refrigerator of the present invention is provided with a refrigeration cycle in which a compressor, a condenser, a capillary tube, and an evaporator are sequentially connected in an annular manner, and a defrosting heater is provided in the vicinity of the evaporator. A bypass circuit having a throttle between the condenser and the evaporator inlet, an on-off valve for controlling a refrigerant flow disposed at a connection portion between the condenser and the bypass circuit, and the on- off valve Open / close timing detection means and an open / close valve control means for opening and closing the open / close valve, the open / close timing detection means is a defrost detection means provided in the vicinity of the evaporator, and the open / close valve control means has a timer, When the defrosting detecting means detects the end of defrosting, the on-off valve is opened in order to promote the return of the lubricating oil together with the refrigerant in the compressor startup transition period after the end of the defrosting, and the timer sets a predetermined time. Close the on-off valve when it has elapsed In which and a closing valve control means.
[0025]
[Action]
With the configuration described above, in the refrigerator of the present invention, when the defrosting detection means that is the electromagnetic valve opening / closing timing detection means detects the end of the defrosting, a signal is sent by the electromagnetic valve control means, and the electromagnetic valve is opened. When the high-pressure vessel compressor is activated, the refrigerant circulates directly from the condenser to the evaporator inlet, and the evaporation pressure rises, so that the suction pressure rises, and further, the high-pressure pressure rises.
[0026]
The circulation of the refrigerant is promoted by the increase of the high pressure, and the state where the balance of the refrigeration cycle is lost is corrected.
[0027]
Since the on- off valve is closed when the timer of the on- off valve control means passes a predetermined time, the low-pressure operation does not occur and the transition to the stable state can be performed smoothly.
[0033]
【Example】
An embodiment of a refrigerator according to the present invention will be described with reference to FIGS. However, the same reference numerals are given to the same components as those in the prior art, and detailed description thereof is omitted.
[0034]
1 is a high-pressure vessel type compressor, 2 is a condenser, 3 is a capillary tube, and 4 is an evaporator. The compressor 1, the condenser 2, the capillary tube 3 and the evaporator 4 are sequentially connected in an annular shape to form a refrigeration cycle. doing.
[0035]
Reference numeral 13 denotes a bypass circuit having a throttle 14, which is formed by connecting the condenser 2 and the inlet of the evaporator 4. A solenoid valve 15 is provided at the connection between the bypass circuit 13 and the condenser 2. Reference numeral 16 denotes electromagnetic valve control means having a timer 17, and reference numeral 18 denotes suction pressure detection means which is electromagnetic valve open / close timing detection means.
[0036]
Reference numeral 5 denotes a main body of the refrigerator, and the inside of the refrigerator is divided into at least two chambers each including at least one freezer compartment 6 and at least one refrigerator compartment 7. A defrosting heater 8 is provided in the vicinity of the evaporator 4.
[0037]
9 detects the time interval set in advance by the defrosting detecting means, the temperature of the evaporator 4 and the frosting state, and detects the end of defrosting during the defrosting operation. The defrost control means (not shown) controls the operation and stop of the compressor 1 and the operation stop of the defrost heater 8 by the detection output of the defrost detection means 9.
[0038]
Next, the operation of the conventional configuration will be described.
The cooling operation by the operation of the compressor 1 is performed, and frosting proceeds in the evaporator 4. Thereby, the heat exchange efficiency of the evaporator 4 decreases, and sufficient cooling operation becomes impossible.
[0039]
This state is detected by the defrost detection means 9 and outputs a defrost start signal to the defrost control means. Upon receiving this signal, the defrost detection means starts defrosting.
[0040]
The defrosting control means stops the compressor 1, operates the defrosting heater 8, and starts defrosting. By operating the defrosting heater 8, the frost on the surface of the evaporator 4 is melted by heat generation.
[0041]
When the frost on the surface of the evaporator 4 is melted, the defrosting detecting means 9 detects that the defrosting is completed when the temperature of the normal evaporator 4 is equal to or higher than a predetermined temperature (generally 10 to 20 ° C.). The defrosting end signal is output to the defrosting control means. In response to this signal, the defrosting control means stops the defrosting heater 8 in order to end the defrosting operation, and then starts the compressor 1. By this operation, the refrigeration cycle starts the cooling operation again.
[0042]
When the temperature of the evaporator 4 rises during the defrosting at the low ambient temperature, and the evaporator 4 and its ambient temperature become higher than the ambient temperature of the compressor 1 and the condenser 2, the saturation pressure of the refrigerant is increased in the evaporator 4. Becomes higher, and the refrigerant moves from the evaporator 4 to the compressor 1 and the condenser 2.
[0043]
At the end of defrosting, the refrigerant in the evaporator 4 almost disappears and remains ubiquitously in the condenser 2 having the lowest temperature during the refrigeration cycle.
[0044]
For this reason, at the time of starting the compressor 1 after defrosting, the refrigerant is not the refrigerant distribution state in the condenser 2 in the normal operation stable state, that is, the state from the gas phase to the liquid phase from the compressor 1 toward the capillary 3. Since the refrigerant stays and there is almost no refrigerant in the evaporator 4, the specific volume of the suction gas is small and cannot be pressurized sufficiently.
[0045]
At the same time, since the refrigerant is ubiquitous in the condenser 2, the liquid refrigerant does not stably reach the inlet of the capillary tube 3, and a large amount of gas is caught in the capillary tube 3, thereby inhibiting the circulation of the refrigerant. As a result, the suction pressure of the compressor 1 decreases.
[0046]
As shown in FIG. 2, if the pressure value detected by the suction pressure detecting means 18 in step 1 is input to the electromagnetic valve control means 16, and if the detected pressure value is not more than a predetermined pressure in step 2, go to step 3. The advance timer 17 is started, and if it is higher, the process returns to step 1.
[0047]
After starting the timer 17 in step 3, the solenoid valve 15 is opened in step 4. Then, in step 5, it is checked whether the timer 17 is counting up. If not counting up, the process returns to step 4, and if counting up, the process proceeds to step 6 and the solenoid valve 15 is closed.
[0048]
When the suction pressure of the compressor 1 is reduced in this way, the bypass circuit 13 is opened, and refrigerant that is unevenly distributed in the condenser 2 is sucked into the inlet portion of the evaporator 4 through the throttle 14, and the evaporation pressure is reduced. 14 increases in accordance with the amount of throttling, and the suction pressure also increases, so the high pressure also increases simultaneously.
[0049]
When the solenoid valve 15 is closed and the bypass circuit 13 is shut off, the increase in the high-pressure pressure promotes the circulation of the refrigerant, and corrects the state in which the balance of the refrigeration cycle is lost.
[0050]
Since there is no low-pressure operation in the start-up transition period, the lubricating oil circulating with the refrigerant returns, so the sliding portion of the compressor 1 does not become dry friction, and abnormal sliding of the compressor 1 occurs. Therefore, the reliability of the compressor 1 can be ensured.
[0051]
Furthermore, since the refrigeration cycle is quickly stabilized after activation after defrosting, the operation time is shortened and power consumption is reduced.
[0052]
Further, as shown in FIGS. 3 and 4, the defrosting detection means 9 is used instead of the suction pressure detection means 18 which is a solenoid valve opening / closing timing detection means, and the defrosting detection means 9 is completed in step 1. If the defrosting is completed in step 2, the process proceeds to step 3, and if not completed, the electromagnetic valve control means 16 may return to step 1.
[0053]
This can reduce the cost for the pressure detecting means.
Further, as shown in FIGS. 5 and 6, a temperature detection means 19 provided at the connection portion between the capillary tube 3 and the evaporator 4 is used instead of the suction pressure detection means 18 which is a solenoid valve opening / closing timing detection means. In step 1, for example, the pipe temperature is taken in from the temperature detecting means 19 which is a thermistor. If the detected temperature value is equal to or lower than the predetermined temperature in step 2, the process proceeds to step 3 and the timer 17 is started. The electromagnetic valve control means 16 that returns to the top may be used.
[0054]
The same effect can be obtained even if the temperature detecting means 19 is bimetal.
The solenoid valve 15 may be closed by energization, may be opened by a power failure, or vice versa, but it is preferably closed during normal refrigerator operation, which takes most of the time, so that power consumption can be reduced. The opening is good. Moreover, what is necessary is just to switch an open state and a closed state by electricity supply.
[0055]
【The invention's effect】
As is apparent from the above description, the refrigerator of the present invention is provided with a refrigeration cycle in which a compressor, a condenser, a capillary tube, and an evaporator are sequentially connected in an annular manner, and is used for defrosting in the vicinity of the evaporator. A heater, a bypass circuit having a throttle between the condenser and the evaporator inlet, an on-off valve for controlling the flow of refrigerant disposed at a connection between the condenser and the bypass circuit, and the opening / closing A valve opening / closing timing detection means and an opening / closing valve control means for opening / closing the opening / closing valve, wherein the opening / closing timing detection means is a defrost detection means provided in the vicinity of the evaporator, and the opening / closing valve control means has a timer. When the defrosting detecting means detects the end of defrosting, the on-off valve is opened to promote the return of the lubricating oil together with the refrigerant in the compressor startup transition period after the end of the defrosting, and the timer is set for a predetermined time. The on-off valve is closed when Since a closing valve control means for said after defrosting bypass circuit is opened, it does not occur a low-pressure operation because after a predetermined time the bypass circuit is closed.
[0059]
As described above, since the low-pressure operation does not occur during the start-up transition period, the lubricating oil circulating with the refrigerant immediately returns, and the sliding portion of the high-pressure vessel compressor does not become dry friction. The reliability of the high-pressure vessel compressor can be ensured without causing abnormal wear of the sliding portion of the compressor.
[0060]
Furthermore, since the balance of the refrigeration cycle is not lost after the start-up, the operation time of the high-pressure vessel compressor is shortened and the power consumption is reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an embodiment of a refrigerator according to the present invention. FIG. 2 is a flowchart showing the operation of a solenoid valve of the embodiment of the refrigerator according to the present invention. FIG. 4 is a flowchart showing the operation of an electromagnetic valve of an embodiment of a refrigerator according to the present invention. FIG. 5 is a cross-sectional view of an embodiment of the refrigerator of the present invention. FIG. 7 is a cross-sectional view of a conventional refrigerator.
DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 Capillary 4 Evaporator 8 Defrosting heater 9 Defrost detection means 13 Bypass circuit 15 Electromagnetic valve 16 Electromagnetic valve control means 17 Timer 18 Suction pressure detection means 19 Temperature detection means

Claims

A refrigeration cycle in which a compressor, a condenser, a capillary tube, and an evaporator are sequentially connected in an annular manner is installed, and a defrosting heater, the condenser, and the evaporator inlet portion are disposed in the vicinity of the evaporator. a bypass circuit having a stop between opening and closing valve for controlling the flow of the refrigerant is disposed in the connection part between said condenser the bypass circuit, and the open-close timing detecting means of said opening and closing valve, the opening and closing of the on-off valve An opening / closing valve control means for performing defrosting detection means provided in the vicinity of the evaporator, the opening / closing valve control means has a timer, and when the defrosting detection means detects the end of defrosting The on-off valve control means for opening the on-off valve to promote the return of the lubricating oil together with the refrigerant in the transition period of the compressor start after the defrosting is completed, and closing the on-off valve when the timer has passed a predetermined time And a refrigerator.