JP3581230B2

JP3581230B2 - Refrigerated open showcase

Info

Publication number: JP3581230B2
Application number: JP07613497A
Authority: JP
Inventors: 徹多和田
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 1997-03-27
Filing date: 1997-03-27
Publication date: 2004-10-27
Anticipated expiration: 2017-03-27
Also published as: JPH10267491A

Description

【０００１】
【発明の属する技術分野】
本発明は収納庫内温度の制御装置を備える冷凍冷蔵オープンショーケースに関するものである。
【０００２】
【従来の技術】
冷凍冷蔵オープンショーケースは周知のように、開口部を有するショーケース本体内をダクト板により前記開口部に連なる商品収納庫と、送風機と冷却器とを備える熱交換機を配設する冷気循環ダクトとに区画し、該冷気循環ダクト端を冷気エアカーテンの吹出口と吸込口として前記開口部の上下に臨ませ、吸込口から取り込んだエアを冷気循環ダクト内に配設の冷却器としての熱交換機で熱交換して冷気とし上端の吹出口から吹き出し、商品収納庫の開口部をこの冷気エアカーテンで閉塞するとともに庫内を所定温度に冷却している。
【０００３】
庫内温度は内部に陳列の要冷凍冷蔵商品の品質を維持するために、一定に保持する必要があるが、そのために、庫内温度を測定する温度測定器を設置し、ここで測定された庫内温度の値に基づいて、熱交換機に冷媒を送る冷媒管の途中に設けた電磁弁などよる温度調節機器のオンオフや冷却器に付着した霜を除去するためのヒータのオンオフを制御装置で制御する。
【０００４】
図３はこの温度制御のためのブロック図で、従来は、冷気の吹出口またはその近傍に設置の庫内温度を測定する温度測定器１と、制御目標温度およびそのディファレンシャル、低温警報温度、低温警報時間、除霜時限、除霜時刻を設定する設定器２がマイクロコンピュータなどを利用する制御装置３の入力側に接続され、制御装置３の出力側には冷媒の供給をオンオフするための電磁弁等による温度調節機器４と冷却器に付着した霜を除去するための除霜用のヒータ５と低温発生時にこれを音や光で報知する警報器６が接続される。
【０００５】
そして、温度測定器１で測定された庫内温度の温度信号と、設定器２で設定された制御目標温度の設定値などが制御装置３に入力され、制御装置３では温度測定器１で測定された庫内温度と設定器２で設定された制御目標温度とを比較して、庫内温度が設定温度である制御目標温度の温度範囲に入るように温度調節機器４に制御信号を出力し温度制御する。なお、送風機は制御装置３に接続されず、常時動作している。
【０００６】
温度測定器１で測定された庫内温度が設定器２で設定された低温警報温度に達すると、制御装置３から警報器６に警報信号が出力され、警報器６が作動するが、その動作を次に図４のフローチャートについて説明する。
【０００７】
設定器２で設定された制御目標温度およびそのディファレンシャル、低温警報温値、低温警報時間、除霜時限、除霜時刻などの設定値を制御装置３で読み込み〔ステップ（ア）〕、これらの値を基に設定温度の上限値と下限値とを算出し〔ステップ（イ）〕、さらに低温警報温度を算出する〔ステップ（ウ）〕。
【０００８】
次に、温度測定器１で測定された庫内温度の測定値を制御装置３で読み込み〔ステップ（エ）〕、この測定値と前記〔ステップ（イ）〕の段階で算出した設定温度の上限値とを比較する〔ステップ（オ）〕。
【０００９】
比較の結果、測定値が上限値よりも大きい場合、すなわち測定された庫内温度が設定温度の上限値よりも高い場合は、温度調節機器４をオンする信号を制御装置３から温度調節機器４に出力し〔ステップ（カ）〕、温度調節機器４をオンし、冷却器への冷媒供給量を増加し冷却能力を高め、庫内温度を下げて、制御目標温度の範囲に入るように制御する。
【００１０】
前記〔ステップ（オ）〕で比較の結果、測定値が上限値よりも小さい場合は、次に測定値を前記〔ステップ（イ）〕の段階で算出した設定温度の下限値と比較する〔ステップ（キ）〕。
【００１１】
比較の結果、測定値が下限値よりも小さい場合、すなわち測定された庫内温度が設定温度の下限値よりも低い場合は、電磁弁などによる温度調節機器４をオフする信号を制御装置３から温度調節機器４に出力し〔ステップ（ク）〕、温度調節機器４をオフし、冷却器への冷媒供給量を減少させ冷却能力を低下させ、庫内温度を上げて制御目標温度の範囲に入るように制御する。
【００１２】
前記〔ステップ（キ）〕で比較の結果、測定値が下限値よりも大きい場合および、測定値が下限値よりも小さくて前記〔ステップ（ク）〕の段階で温度調節機器４をオフした場合は、さらに次にこの測定値を前記〔ステップ（ウ）〕の段階で算出した低温警報温度と比較し〔ステップ（ケ）〕、比較の結果、測定値が低温警報温度よりも大きい場合は、異常低温は発生していないものと判断して低温警報時間のカウントをリセットし〔ステップ（ス）〕、低温警報を解除して〔ステップ（セ）〕、温度測定値の読み込みを再開する〔ステップ（エ）〕。
【００１３】
これに対して、前記〔ステップ（ケ）〕で比較の結果、測定値が低温警報温度よりも小さい場合は、低温警報時間のカウントを開始し〔ステップ（コ）〕、低温警報温度の状態が予め設定されている設定時間に達すれば、異常低温が発生しているものと判断して〔ステップ（サ）〕、制御装置３から警報器６に低温警報信号を出力し〔ステップ（シ）〕、警報器６で低温警報する。
【００１４】
その後、〔ステップ（エ）〕の段階に戻り、庫内温度の測定値の読み込みを再開し、この測定値を設定温度の上限値、下限値と比較し、測定温度が制御目標温度の範囲になければ温度調節機器４をオンオフ制御して、測定温度を制御目標温度の範囲に入るよう制御し、さらに低温警報温度値と比較してこれよりも低ければ警報し、これを繰り返す。
【００１５】
【発明が解決しようとする課題】
このように庫内温度の制御は電磁弁のオンオフなどによる温度調節機器の制御により行うものであり、低温異常発生時でも冷却器への冷媒の供給量を調整して冷媒循環を制御するために電磁弁を閉じるだけであり、この間も、送風機の運転は停止せず運転が続行されている。
【００１６】
このため、商品収納庫の開口を閉塞するエアカーテンはここに形成されたままの状態にあり、庫内と外気とが依然として遮断されたままで、このエアカーテンが庫内よりも高い温度の外気を遮断して庫内の低温異常状態が長引く事態が発生していた。
【００１７】
本発明の目的は前記従来例の不都合を解消し、低温異常の発生時に温度調節機器だけでなく、送風機やヒータも制御する装置を備えることにより、低温異常状態を早期に解消し、庫内温度の異常低下を防げる冷凍冷蔵オープンショーケースを提供することにある。
【００１８】
【課題を解決するための手段】
本発明は前記目的を達成するため、開口部を有するショーケース本体内をダクト板により前記開口部に連なる商品収納庫と、送風機と冷却器と除霜ヒータとを備える熱交換機を配設する冷気循環ダクトとに区画し、該冷気循環ダクトの両端を冷気エアカーテンの吹出口と吸込口として前記開口部の上下に臨ませる冷凍冷蔵オープンショーケースにおいて、
収納庫内温度を測定する温度測定器と、目標温度、低温警報温度を設定する設定器と、前記冷却器への冷媒の供給を調節する温度調節機器と、前記温度測定器と前記設定器からの入力に基づいて収納庫内温度が前記目標温度に入るように前記温度調節機器の動作を制御するとともに、前記温度測定器が前記低温警報温度を検出した際に、前記温度調節機器による冷媒の供給と前記送風機の動作を停止させ、前記送風機の停止時間が所定時間を経過しても、前記低温警報温度が検出される場合は、前記送風機と前記除霜ヒータを運転させる。
【００１９】
これにより、ショーケースの開口部を閉塞するエアカーテンを一旦解除して、高温の外気を商品収納庫内に取り込み庫内の温度が上昇するようにしても、測定温度が低温警報温度以下のまま、所定時間を経過した場合は、送風機の作動を開始するとともに、冷却器の除霜用のヒータに通電しこれを加熱する。よって、送風機が作動状態になってもヒータによる暖気が循環するので、庫内温度が上昇し、制御目標温度に短時間で到達できるとともに短時間で異常低温状態を解消できるものである。
【００２０】
【発明の実施の形態】
以下、図面について本発明の実施の形態を詳細に説明する。図１は本発明の冷凍冷蔵オープンショーケースの温度制御装置の実施の形態を示す制御ブロック図で、図３について既に説明した従来例と同一の構成要素には同一の参照符号を付してある。
【００２１】
本発明の制御ブロックも、基本的には従来と同様、前記したように冷気の吹出口またはその近傍に設置の庫内温度を測定する温度測定器１と、制御目標温度およびそのディファレンシャル、低温警報温度、低温警報時間、除霜時限、除霜時刻を設定する設定器２がマイクロコンピュータなどを利用する制御装置３の入力側に接続され、制御装置３の出力側には冷媒の供給をオンオフするための電磁弁などによる温度調節機器４と低温発生時にこれを音や光で報知する警報器６と除霜用のヒータ５が接続される。
【００２２】
本発明ではかかる構成に加えて、制御装置３の出力側に送風機・ヒータ制御回路８を接続し、この送風機・ヒータ制御回路８を介して送風機７とヒータ５とを制御装置３に接続した。
【００２３】
次に動作を説明すると、温度測定器１で測定された庫内温度の測定値が、設定器２で設定された制御目標温度などの値に基に設定される上限値、下限値の範囲内に入るように制御する動作、および低温警報温度以下の場合に警報する動作は従来と同様である。
【００２４】
かかる動作を図２のフローチャートについてまず説明すると、既に説明したものと同様であるが、設定器２で設定された制御目標温度およびそのディファレンシャル、低温警報温値、低温警報時間、除霜時限、除霜時刻などの設定値を制御装置３で読み込み〔ステップ（ア）〕、これらの値を基に設定温度の上限値と下限値とを算出し〔ステップ（イ）〕、さらに低温警報温度を算出する〔ステップ（ウ）〕。
【００２５】
次に、温度測定器１で測定された庫内温度の測定値を制御装置３で読み込み〔ステップ（エ）〕、この測定値と前記〔ステップ（イ）〕の段階で算出した設定温度の上限値とを比較する〔ステップ（オ）〕。
【００２６】
比較の結果、測定値が上限値よりも大きい場合、すなわち測定された庫内温度が設定温度の上限値よりも高い場合は、温度調節機器４をオンする信号を制御装置３から温度調節機器４に出力し〔ステップ（カ）〕、温度調節機器４をオンし、冷却器への冷媒供給量を増加し冷却能力を高め、庫内温度を下げて、制御目標温度の範囲に入るように制御する。
【００２７】
前記〔ステップ（オ）〕で比較の結果、測定値が上限値よりも小さい場合は、次に測定値を前記〔ステップ（イ）〕の段階で算出した設定温度の下限値と比較する〔ステップ（キ）〕。
【００２８】
比較の結果、測定値が下限値よりも小さい場合、すなわち測定された庫内温度が設定温度の下限値よりも低い場合は、温度調節機器４をオフする信号を制御装置３から温度調節機器４に出力し〔ステップ（ク）〕、温度調節機器４をオフし、冷却器への冷媒供給量を減少させ冷却能力を低下させ、庫内温度を上げて制御目標温度の範囲に入るように制御する。
【００２９】
前記〔ステップ（キ）〕で比較の結果、測定値が下限値よりも大きい場合および、測定値が下限値よりも小さくて前記〔ステップ（ク）〕の段階で温度調節機器４をオフした場合は、さらに次にこの測定値を前記〔ステップ（ウ）〕の段階で算出した低温警報温度と比較し〔ステップ（ケ）〕、比較の結果、測定値が低温警報温度よりも大きい場合は、異常低温は発生していないものと判断して低温警報時間のカウントをリセットし〔ステップ（ス）〕、低温警報を解除して〔ステップ（セ）〕、送風機７の作動が停止していればこれを作動させて〔ステップ（ソ）〕、温度測定値の読み込みを再開する〔ステップ（エ）〕。
【００３０】
これに対して、前記〔ステップ（ケ）〕で比較の結果、測定値が低温警報温度よりも小さい場合は、低温警報時間のカウントを開始し〔ステップ（コ）〕、低温警報温度の状態が予め設定されている設定時間に達すれば、異常低温が発生しているものと判断して〔ステップ（サ）〕、制御装置３から警報器６に低温警報信号を出力し〔ステップ（シ）〕、警報器６で低温警報する。
【００３１】
同時に制御装置３から送風機・ヒータ制御回路８に出力して、ここから送風機７の運転を停止する信号を出力し、送風機７を停止する〔ステップ（タ）〕。これにより、ショーケースの開口部に形成されていたエアカーテンがなくなり、温度の高い外気が庫内に侵入して庫内温度を上昇させる。
【００３２】
その後、送風機７の停止時間のカウントを開始し〔ステップ（チ）〕、停止時間が設定時間に達すれば〔ステップ（ツ）〕、停止時間のカウントをリセットして〔ステップ（テ）〕、送風機・ヒータ制御回路８からの出力により送風機７の運転を開始するとともにヒータ５の作動を開始する〔ステップ（ト）〕。
【００３３】
これにより送風機７の作動が開始してもヒータ５にも同時に通電されるから、冷却器は除霜状態となり、低温の冷気が吹き出されることはなく、庫内温度が低下することはない。こうして異常低温の状態が解消される。
【００３４】
そして、送風機７とヒータ５の作動時間をカウントし〔ステップ（ナ）〕、設定時間が経過すれば〔ステップ（ニ）〕、送風機７とヒータ５の作動を停止し〔ステップ（ヌ）〕、作動時間のカウントをリセットして〔ステップ（ネ）〕、測定値の読み込みを再度行う〔ステップ（オ）〕。
【００３５】
一方、送風機７とヒータ５を同時に作動している最中で、まだ設定時間に達していないとき〔ステップ（ニ）〕、温度測定器１で測定された庫内温度の測定値を読み込んで〔ステップ（ノ）〕、この測定値が低温警報温度よりも高くなっていれば〔ステップ（ハ）〕、制御装置３で異常低温状態が解消されたものと判断して低温警報時間のカウントをリセットし〔ステップ（ヒ）〕、低温警報を解除して〔ステップ（フ）〕、送風機・ヒータ制御回路８に出力してヒータ５の作動を停止する〔ステップ（へ）〕。
【００３６】
なお、前記実施形態では異常低温発生時に送風機７を一定時間停止した後に、送風機７とヒータ５を作動させたが、送風機７の一定時間停止だけで異常低温状態を解消するようにしてもよい。
【００３７】
また、測定値が設定下限値に達した段階で、送風機７を間欠運転、または所定時間停止、または、設定下限値以上に測定値が達するまで送風機７を停止、または、設定下限値にプラスαの温度に達するまで送風機７を停止するなど、種々の方法が考えられる。
【００３８】
【発明の効果】
以上述べたように本発明の冷凍冷蔵オープンショーケースの温度制御装置は、開口部を有するショーケース本体内をダクト板により前記開口部に連なる商品収納庫と、送風機と冷却器と除霜ヒータとを備える熱交換機を配設する冷気循環ダクトとに区画し、該冷気循環ダクトの両端を冷気エアカーテンの吹出口と吸込口として前記開口部の上下に臨ませる冷凍冷蔵オープンショーケースにおいて、収納庫内温度を測定する温度測定器と、目標温度、低温警報温度を設定する設定器と、前記冷却器への冷媒の供給を調節する温度調節機器と、前記温度測定器と前記設定器からの入力に基づいて収納庫内温度が前記目標温度に入るように前記温度調節機器の動作を制御するとともに、前記温度測定器が前記低温警報温度を検出した際に、前記温度調節機器による冷媒の供給と前記送風機の動作を停止させ、前記送風機の停止時間が所定時間を経過しても、前記低温警報温度が検出される場合は、前記送風機と前記除霜ヒータを運転させる。
【００３９】
これにより、ショーケースの開口部を閉塞するエアカーテンを一旦解除して、高温の外気を商品収納庫内に取り込み庫内の温度が上昇するようにしても、測定温度が低温警報温度以下のまま、所定時間を経過した場合は、送風機の作動を開始するとともに、冷却器の除霜用のヒータに通電しこれを加熱する。よって、送風機が作動状態になってもヒータによる暖気が循環するので、庫内温度が上昇し、制御目標温度に短時間で到達できるとともに短時間で異常低温状態を解消できるものである。
【図面の簡単な説明】
【図１】本発明の冷凍冷蔵オープンショーケースの温度制御装置の実施の形態を示す制御ブロック図である。
【図２】本発明の冷凍冷蔵オープンショーケースの温度制御装置の温度制御の動作を示すフローチャートである。
【図３】従来の冷凍冷蔵オープンショーケースの温度制御装置の制御ブロック図である。
【図４】従来の冷凍冷蔵オープンショーケースの温度制御装置の温度制御の動作を示すフローチャートである。
【符号の説明】
１…温度測定器
２…設定器
３…制御装置
４…温度調節機器
５…ヒータ
６…警報器
７…送風機
８…送風機・ヒータ制御回路[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a freezer-refrigerated open showcase provided with a control device for a temperature in a storage.
[0002]
[Prior art]
As is well known, a freezer and refrigerated open showcase has a showcase main body having an opening, a product storage connected to the opening by a duct plate, and a cool air circulation duct in which a heat exchanger including a blower and a cooler is arranged. A heat exchanger as a cooler disposed in the cool air circulation duct, with the ends of the cool air circulation duct facing the upper and lower sides of the opening as an outlet and a suction port for a cool air air curtain. Then, heat is exchanged into cold air and blown out from the upper outlet, and the opening of the product storage is closed with the cool air curtain and the inside of the storage is cooled to a predetermined temperature.
[0003]
The temperature inside the refrigerator must be kept constant in order to maintain the quality of frozen and refrigerated products on display inside, but for that purpose, a temperature measuring device that measures the temperature inside the refrigerator was installed and measured here. Based on the value of the temperature in the refrigerator, the control device turns on / off a temperature control device such as an electromagnetic valve provided in the middle of a refrigerant pipe that sends a refrigerant to a heat exchanger and turns on / off a heater for removing frost attached to a cooler. Control.
[0004]
FIG. 3 is a block diagram for this temperature control. Conventionally, a temperature measuring device 1 for measuring the temperature inside a refrigerator installed at or near a cold air outlet, a control target temperature and its differential, a low temperature alarm temperature, a low temperature A setting device 2 for setting an alarm time, a defrost time limit, and a defrost time is connected to an input side of a control device 3 using a microcomputer or the like, and an output side of the control device 3 is an electromagnetic device for turning on and off the supply of refrigerant. A temperature control device 4 such as a valve, a defrosting heater 5 for removing frost adhering to the cooler, and an alarm device 6 for notifying the occurrence of low temperature by sound or light are connected.
[0005]
Then, the temperature signal of the internal temperature measured by the temperature measuring device 1 and the set value of the control target temperature set by the setting device 2 are input to the control device 3, and the control device 3 measures the temperature by the temperature measuring device 1. The control unit 4 compares the set internal temperature with the control target temperature set by the setting unit 2 and outputs a control signal to the temperature control device 4 so that the internal temperature falls within the temperature range of the control target temperature which is the set temperature. Control the temperature. Note that the blower is not connected to the control device 3 and is constantly operating.
[0006]
When the internal temperature measured by the temperature measuring device 1 reaches the low-temperature alarm temperature set by the setting device 2, an alarm signal is output from the control device 3 to the alarm device 6, and the alarm device 6 is activated. Next, the flowchart of FIG. 4 will be described.
[0007]
The control device 3 reads set values such as the control target temperature set by the setting device 2 and its differential, a low-temperature alarm temperature value, a low-temperature alarm time, a defrost time limit, and a defrost time [Step (A)]. Based on the above, the upper limit value and the lower limit value of the set temperature are calculated [step (a)], and the low temperature alarm temperature is further calculated [step (c)].
[0008]
Next, the measured value of the internal temperature measured by the temperature measuring device 1 is read by the control device 3 (step (d)), and the measured value and the upper limit of the set temperature calculated in the step (a) are described. Compare with the value [step (e)].
[0009]
As a result of the comparison, when the measured value is larger than the upper limit value, that is, when the measured inside temperature is higher than the set temperature upper limit value, a signal to turn on the temperature control device 4 is sent from the control device 3 to the temperature control device 4. [Step (f)], the temperature control device 4 is turned on, the amount of refrigerant supplied to the cooler is increased, the cooling capacity is increased, the temperature in the refrigerator is reduced, and control is performed so as to fall within the control target temperature range. I do.
[0010]
If the measured value is smaller than the upper limit value as a result of the comparison in [Step (e)], the measured value is then compared with the lower limit value of the set temperature calculated in the step [A]. (G)].
[0011]
As a result of the comparison, when the measured value is smaller than the lower limit value, that is, when the measured inside temperature is lower than the lower limit value of the set temperature, the control device 3 sends a signal for turning off the temperature control device 4 such as an electromagnetic valve. The temperature is output to the temperature control device 4 (step (h)), the temperature control device 4 is turned off, the amount of refrigerant supplied to the cooler is reduced, the cooling capacity is reduced, and the internal temperature is raised to the range of the control target temperature. Control to enter.
[0012]
As a result of the comparison in [Step (G)], when the measured value is larger than the lower limit value, and when the measured value is smaller than the lower limit value and the temperature control device 4 is turned off in the stage of [Step (C)]. Then, next, this measured value is compared with the low-temperature alarm temperature calculated in the step (C) [Step (G)]. As a result of the comparison, if the measured value is higher than the low-temperature alarm temperature, Judging that abnormal low temperature has not occurred, reset the low temperature alarm time count [Step (S)], release the low temperature alarm [Step (S)], and restart reading the temperature measurement value [Step (S)]. (D)].
[0013]
On the other hand, if the measured value is smaller than the low-temperature alarm temperature as a result of the comparison in [Step (g)], counting of the low-temperature alarm time is started [step (k)], and the state of the low-temperature alarm temperature is changed. If the preset time has been reached, it is determined that abnormal low temperature has occurred (step (c)), and a low-temperature warning signal is output from the control device 3 to the alarm device 6 (step (c)). , A low temperature alarm is issued by the alarm 6.
[0014]
Thereafter, returning to the step (d), the reading of the measured value of the internal temperature is restarted, and the measured value is compared with the upper limit value and the lower limit value of the set temperature, and the measured temperature is set within the range of the control target temperature. If not, the temperature control device 4 is turned on / off to control the measured temperature to fall within the range of the control target temperature. Further, the temperature is compared with the low-temperature alarm temperature value, and if it is lower than this, an alarm is issued and this is repeated.
[0015]
[Problems to be solved by the invention]
As described above, the control of the temperature in the refrigerator is performed by controlling the temperature control device by turning on / off the solenoid valve, etc., in order to control the refrigerant circulation by adjusting the supply amount of the refrigerant to the cooler even when a low temperature abnormality occurs. Only the solenoid valve is closed, and during this time, the operation of the blower is not stopped but is continued.
[0016]
For this reason, the air curtain which closes the opening of the product storage is in a state where it is formed here, and the inside of the storage and the outside air are still shut off, and the air curtain blocks the outside air having a higher temperature than the inside of the storage. There was a situation in which the low-temperature abnormal state in the refrigerator was prolonged due to the shutdown.
[0017]
An object of the present invention is to eliminate the disadvantages of the conventional example and to provide a device for controlling not only a temperature control device but also a blower and a heater when a low-temperature abnormality occurs, thereby eliminating a low-temperature abnormality state at an early stage, and reducing the internal temperature. It is an object of the present invention to provide a freezer-refrigerated open showcase that can prevent abnormal lowering of the refrigerator.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a cold air in which a showcase body having an opening is provided with a commodity storage connected to the opening by a duct plate and a heat exchanger including a blower, a cooler, and a defrost heater. In a refrigerating and refrigerated open showcase which is divided into a circulation duct and has both ends of the cool air circulation duct facing above and below the opening as an outlet and a suction port of a cool air curtain,
A temperature measuring device for measuring the temperature in the storage, a target temperature, a setting device for setting a low temperature alarm temperature, a temperature adjusting device for adjusting supply of a refrigerant to the cooler, and the temperature measuring device and the setting device. While controlling the operation of the temperature adjusting device so that the temperature in the storage is within the target temperature based on the input of, when the temperature measuring device detects the low temperature alarm temperature, the refrigerant of the refrigerant by the temperature adjusting device The supply and the operation of the blower are stopped, and if the low-temperature alarm temperature is detected even after the stop time of the blower exceeds a predetermined time, the blower and the defrost heater are operated.
[0019]
As a result, even if the air curtain that closes the opening of the showcase is once released and high-temperature outside air is taken into the product storage and the temperature inside the storage rises, the measured temperature remains below the low-temperature alarm temperature. When a predetermined time has elapsed, the operation of the blower is started, and the heater for defrosting the cooler is energized to heat it. Therefore, even when the blower is in the operating state, the warm air from the heater circulates, so that the temperature in the refrigerator rises, the control target temperature can be reached in a short time, and the abnormally low temperature state can be eliminated in a short time.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a control block diagram showing an embodiment of a temperature control device for a freezer and refrigerated open showcase of the present invention. The same reference numerals are given to the same components as those in the conventional example already described with reference to FIG. .
[0021]
As described above, the control block of the present invention also includes a temperature measuring device 1 for measuring the internal temperature of the refrigerator installed at or near the outlet of the cool air as described above, a control target temperature and its differential, and a low-temperature alarm. A setting device 2 for setting a temperature, a low-temperature warning time, a defrost time limit, and a defrost time is connected to an input side of a control device 3 using a microcomputer or the like, and turns on and off supply of a refrigerant to an output side of the control device 3. A temperature control device 4 such as an electromagnetic valve, a warning device 6 for notifying the occurrence of low temperature by sound or light, and a heater 5 for defrosting are connected.
[0022]
In the present invention, in addition to the above configuration, a blower / heater control circuit 8 is connected to the output side of the control device 3, and the blower 7 and the heater 5 are connected to the control device 3 via the blower / heater control circuit 8.
[0023]
Next, the operation will be described. The measured value of the internal temperature measured by the temperature measuring device 1 is within the range of the upper limit value and the lower limit value set based on the value such as the control target temperature set by the setting device 2. The operation of controlling the temperature to enter and the operation of alarming when the temperature is equal to or lower than the low temperature alarm temperature are the same as those in the related art.
[0024]
This operation will be described first with reference to the flowchart of FIG. 2, which is the same as that already described, except that the control target temperature set by the setting unit 2 and its differential, low temperature alarm temperature value, low temperature alarm time, defrost time limit, and defrost time limit are set. The set values such as the frost time are read by the control device 3 [Step (A)], and the upper limit value and the lower limit value of the set temperature are calculated based on these values [Step (A)], and the low temperature alarm temperature is further calculated. [Step (c)].
[0025]
Next, the measured value of the internal temperature measured by the temperature measuring device 1 is read by the control device 3 (step (d)), and the measured value and the upper limit of the set temperature calculated in the step (a) are described. Compare with the value [step (e)].
[0026]
As a result of the comparison, when the measured value is larger than the upper limit value, that is, when the measured inside temperature is higher than the set temperature upper limit value, a signal to turn on the temperature control device 4 is sent from the control device 3 to the temperature control device 4. [Step (f)], the temperature control device 4 is turned on, the amount of refrigerant supplied to the cooler is increased, the cooling capacity is increased, the temperature in the refrigerator is reduced, and control is performed so as to fall within the control target temperature range. I do.
[0027]
If the measured value is smaller than the upper limit value as a result of the comparison in [Step (e)], the measured value is then compared with the lower limit value of the set temperature calculated in the step [A]. (G)].
[0028]
As a result of the comparison, when the measured value is smaller than the lower limit value, that is, when the measured inside temperature is lower than the lower limit value of the set temperature, a signal to turn off the temperature control device 4 is sent from the control device 3 to the temperature control device 4. [Step (h)], the temperature control device 4 is turned off, the amount of refrigerant supplied to the cooler is reduced, the cooling capacity is reduced, and the temperature in the refrigerator is increased so as to be in the range of the control target temperature. I do.
[0029]
As a result of the comparison in [Step (G)], when the measured value is larger than the lower limit value, and when the measured value is smaller than the lower limit value and the temperature control device 4 is turned off in the stage of [Step (C)]. Then, next, this measured value is compared with the low-temperature alarm temperature calculated in the step (C) [Step (G)]. As a result of the comparison, if the measured value is higher than the low-temperature alarm temperature, If it is determined that abnormal low temperature has not occurred, the count of the low temperature alarm time is reset [Step (S)], the low temperature alarm is released [Step (S)], and if the operation of the blower 7 is stopped. By operating this [Step (G)], reading of the temperature measurement value is restarted [Step (D)].
[0030]
On the other hand, if the measured value is smaller than the low-temperature alarm temperature as a result of the comparison in [Step (g)], counting of the low-temperature alarm time is started [step (k)], and the state of the low-temperature alarm temperature is changed. If the preset time has been reached, it is determined that abnormal low temperature has occurred (step (c)), and a low-temperature warning signal is output from the control device 3 to the alarm device 6 (step (c)). , A low temperature alarm is issued by the alarm 6.
[0031]
At the same time, the controller 3 outputs a signal to the blower / heater control circuit 8, which outputs a signal for stopping the operation of the blower 7, and stops the blower 7 (step (T)). As a result, the air curtain formed at the opening of the showcase disappears, and the high-temperature outside air enters the inside of the refrigerator and raises the temperature inside the refrigerator.
[0032]
Thereafter, the counting of the stop time of the blower 7 is started [Step (H)]. When the stop time reaches the set time [Step (T)], the stop time count is reset [Step (T)]. The operation of the blower 7 is started by the output from the heater control circuit 8 and the operation of the heater 5 is started [step (g)].
[0033]
Thus, even when the operation of the blower 7 is started, the heater 5 is also energized at the same time, so that the cooler is in a defrosted state, no low-temperature cold air is blown out, and the inside temperature does not decrease. Thus, the abnormally low temperature state is eliminated.
[0034]
Then, the operation time of the blower 7 and the heater 5 is counted [Step (N)]. When the set time has elapsed [Step (D)], the operation of the blower 7 and the heater 5 is stopped [Step (N)], The count of the operation time is reset [Step (N)], and reading of the measured value is performed again [Step (E)].
[0035]
On the other hand, when the blower 7 and the heater 5 are being operated at the same time and the set time has not yet been reached (step (d)), the measured value of the internal temperature measured by the temperature measuring device 1 is read and [ Step (No)], if this measured value is higher than the low-temperature alarm temperature [Step (C)], the controller 3 determines that the abnormal low-temperature state has been resolved and resets the low-temperature alarm time count. [Step (h)], the low-temperature alarm is released [Step (F)], and the output is sent to the blower / heater control circuit 8 to stop the operation of the heater 5 [Step (F)].
[0036]
In the above-described embodiment, the blower 7 and the heater 5 are operated after stopping the blower 7 for a certain time when an abnormal low temperature occurs, but the abnormal low temperature state may be eliminated only by stopping the blower 7 for a certain time.
[0037]
Further, when the measured value reaches the set lower limit, the blower 7 is operated intermittently or stopped for a predetermined time, or the blower 7 is stopped until the measured value reaches the set lower limit or more, or the set lower limit is increased by α. Various methods are conceivable, such as stopping the blower 7 until the temperature of the blower 7 is reached.
[0038]
【The invention's effect】
As described above, the temperature control device of the freezing and refrigeration open showcase of the present invention includes a showcase body having an opening, a product storage connected to the opening by a duct plate, a blower, a cooler, and a defrost heater. A cold air circulation duct in which a heat exchanger provided with a cold air circulation duct is provided, and both ends of the cold air circulation duct are exposed above and below the opening as an outlet and a suction port of a cold air curtain, respectively. A temperature measuring device for measuring an internal temperature, a target temperature, a setting device for setting a low temperature alarm temperature, a temperature adjusting device for adjusting supply of refrigerant to the cooler, and an input from the temperature measuring device and the setting device Controlling the operation of the temperature control device so that the temperature in the storage is within the target temperature based on the temperature, and when the temperature measuring device detects the low temperature alarm temperature, The supply of the refrigerant by the node device and the operation of the blower are stopped, and even if the stop time of the blower exceeds a predetermined time, if the low-temperature alarm temperature is detected, the blower and the defrost heater are operated. .
[0039]
As a result, even if the air curtain that closes the opening of the showcase is once released and high-temperature outside air is taken into the product storage and the temperature inside the storage rises, the measured temperature remains below the low-temperature alarm temperature. When a predetermined time has elapsed, the operation of the blower is started, and the heater for defrosting the cooler is energized to heat it. Therefore, even when the blower is in the operating state, the warm air from the heater circulates, so that the temperature in the refrigerator rises, the control target temperature can be reached in a short time, and the abnormally low temperature state can be eliminated in a short time.
[Brief description of the drawings]
FIG. 1 is a control block diagram showing an embodiment of a temperature control device for a freezing and refrigeration open showcase of the present invention.
FIG. 2 is a flowchart showing an operation of temperature control of the temperature control device of the freezing and refrigeration open showcase of the present invention.
FIG. 3 is a control block diagram of a conventional temperature control device for a freezing and refrigeration open showcase.
FIG. 4 is a flowchart showing a temperature control operation of a conventional temperature control device for a freezing and refrigeration open showcase.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Temperature measuring device 2 ... Setting device 3 ... Control device 4 ... Temperature adjusting device 5 ... Heater 6 ... Alarm 7 ... Blower 8 ... Blower / heater control circuit

Claims

The interior of the showcase body having an opening is partitioned into a product storage connected to the opening by a duct plate, and a cool air circulation duct provided with a heat exchanger including a blower, a cooler, and a defrost heater, and the cool air circulation is performed. In a refrigerated open showcase in which both ends of the duct are exposed above and below the opening as an outlet and a suction port of a cold air curtain,
A temperature measuring device for measuring the temperature in the storage, a target temperature, a setting device for setting a low temperature alarm temperature, a temperature adjusting device for adjusting supply of a refrigerant to the cooler, and the temperature measuring device and the setting device. While controlling the operation of the temperature adjusting device so that the temperature in the storage is within the target temperature based on the input of, when the temperature measuring device detects the low temperature alarm temperature, the refrigerant of the refrigerant by the temperature adjusting device A control device that stops the supply and the operation of the blower, and operates the blower and the defrost heater when the low-temperature alarm temperature is detected even when the stop time of the blower exceeds a predetermined time. A freezer and refrigerated open showcase.