JP3556798B2

JP3556798B2 - Temperature control device for refrigerated open showcase

Info

Publication number: JP3556798B2
Application number: JP7613097A
Authority: JP
Inventors: 保之小宮
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 1997-03-27
Filing date: 1997-03-27
Publication date: 2004-08-25
Anticipated expiration: 2017-03-27
Also published as: JPH10267490A

Description

【０００１】
【発明の属する技術分野】
本発明は冷凍冷蔵オープンショーケースの庫内温度の温度制御装置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の開閉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４と低温発生時にこれを音や光で報知する警報器５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に制御信号を出力し温度制御する。
【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５に警報信号が出力され、警報器５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、電磁弁４をオンする信号を制御装置３から電磁弁４に出力し〔ステップ（カ）〕、電磁弁４を開き、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４をオフする信号を制御装置３から電磁弁４に出力し〔ステップ（ク）〕、電磁弁４を閉じ、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）〕の段階で電磁弁４を閉じた場合は、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５に低温警報信号を出力し〔ステップ（シ）〕、警報器５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電磁弁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により行うものであるが、これは制御装置からの制御信号の出力で電磁弁をオンオフできるという前提にたつものである。しかし、制御装置からオフ信号を出力しているにもかかわらず、何らかの理由によって電磁弁そのものが開の状態になったままで異常低温が発生した場合は、これをオフさせて閉じる手段がないため、異常低温を解消することができなかった。
【００１６】
本発明の目的は前記従来例の不都合を解消し、制御装置からオフ信号を出力しているにもかかわらず、何らかの理由によって電磁弁そのものが開の状態になったままで異常低温が発生した場合に、電磁弁を別途制御する手段を付加することにより、かかる事態でも電磁弁のオンオフ制御を可能として異常低温の発生を防止できる冷凍冷蔵オープンショーケースの温度制御装置を提供することにある。
【００１７】
【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、第１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る冷凍冷蔵オープンショーケースに配設する温度制御装置であって、庫内温度を測定する温度測定器と、制御目標温度、低温警報温度および低温警報時間を設定する設定器と、前記温度測定器と設定器とが入力側に接続されてこれら温度測定器と設定器からの入力に基づいて庫内温度が設定温度範囲に入るように、熱交換装置に冷媒を送る冷媒管の途中に設けた電磁弁の開閉動作を制御する制御装置と、前記温度測定器で測定された温度と設定器に設定された温度とを比較して測定温度が低温警報温度以下で、低温警報時間を経過したとき警報器に警報信号を出力する制御装置とを備える冷凍冷蔵オープンショーケースの温度制御装置において、庫内温度が低温警報温度にあるため、前記制御装置によって電磁弁を閉じて冷媒の循環を停止するよう制御した後にも、低温警報が継続される場合に、前記制御装置の出力側に接続され、前記電磁弁を一定時間毎に繰り返し開閉動作させる電磁弁制御回路を備えたことにより、例えば電磁弁を閉じる際に、電磁弁に異物が挟まって弁が完全に閉じない状態であるために異常低温が発生した場合でも、電磁弁の開閉を制御する電磁弁制御回路からの出力によって電磁弁を挟まった異物を振り落とすように一定時間に繰り返して開閉動作を与えることで、異物の除去ができるため、電磁弁を完全に閉じることができるとともに、異常低温状態の継続を防止できる。
【００１８】
第２に、電磁弁制御回路への制御装置からの出力は、該制御装置から警報器への出力と同時に行うことにより、異常低温発生時には電磁弁の開閉制御を確実に行うことができ、また、電磁弁制御回路からの出力による電磁弁の開閉制御は異常低温発生時のみすることで、設定温度の下限値以下になった場合は制御装置からの出力で直接制御することもできる。
【００１９】
【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。
【００２０】
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４と低温発生時にこれを音や光で報知する警報器５が接続される。
【００２１】
本発明ではかかる構成に加えて、低温異常発生時に電磁弁４の開閉を格別に制御する手段として、電磁弁４を一定時間毎に開閉制御する電磁弁制御回路６を制御装置３と電磁弁４との間に設け、制御回路３からの出力を電磁弁制御回路６を介して電磁弁４に導入した。
【００２２】
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。
【００２３】
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）〕。
【００２４】
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）〕。
【００２５】
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、電磁弁４をオンする信号を制御装置３から電磁弁４に出力し〔ステップ（カ）〕、電磁弁４を開き、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。
【００２６】
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）〕。
【００２７】
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４をオフする信号を制御装置３から電磁弁４に出力し〔ステップ（ク）〕、電磁弁４を閉じ、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。
【００２８】
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）〕の段階で電磁弁４を閉じた場合は、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）〕。
【００２９】
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５に低温警報信号を出力し〔ステップ（シ）〕、警報器５で低温警報する。
【００３０】
同時に制御装置３から電磁弁制御回路６に出力して、ここから電磁弁４を閉にする信号を電磁弁４に出力し電磁弁４を閉じる〔ステップ（ソ）〕。その後、電磁弁４の閉時間のカウントを開始し〔ステップ（タ）〕、電磁弁４の閉時間が設定時間に達すれば〔ステップ（チ）〕、電磁弁４の閉時間のカウントをリセットして〔ステップ（ツ）〕、電磁弁４を開にする信号を電磁弁制御回路６から出力して〔ステップ（テ）〕電磁弁４を開き、今度は電磁弁４の開時間のカウントを開始し〔ステップ（ト）〕する。
【００３１】
そして、電磁弁４の開時間が設定時間に達すれば〔ステップ（ナ）〕、電磁弁４の開時間のカウントをリセットして〔ステップ（ニ）〕、電磁弁４を閉にする信号を電磁弁制御回路６から出力して〔ステップ（ヌ）〕電磁弁４を閉じる。
【００３２】
このように低温警報が発せられたときは、同時に電磁弁制御回路６からの出力で電磁弁４を一定時間毎に開閉制御し、庫内温度の測定値が低温警報温度以下に下がらないように制御する。
【００３３】
【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、第１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る冷凍冷蔵オープンショーケースに配設する温度制御装置であって、庫内温度を測定する温度測定器と、制御目標温度、低温警報温度および低温警報時間を設定する設定器と、前記温度測定器と設定器とが入力側に接続されてこれら温度測定器と設定器からの入力に基づいて庫内温度が設定温度範囲に入るように、熱交換装置に冷媒を送る冷媒管の途中に設けた電磁弁の開閉動作を制御する制御装置と、前記温度測定器で測定された温度と設定器に設定された温度とを比較して測定温度が低温警報温度以下で、低温警報時間を経過したとき警報器に警報信号を出力する制御装置とを備える冷凍冷蔵オープンショーケースの温度制御装置において、庫内温度が低温警報温度にあるため、前記制御装置によって電磁弁を閉じて冷媒の循環を停止するよう制御した後にも、低温警報が継続される場合に、前記制御装置の出力側に接続され、前記電磁弁を一定時間毎に繰り返し開閉動作させる電磁弁制御回路を備えたことにより、例えば電磁弁を閉じる際に、電磁弁に異物が挟まって弁が完全に閉じない状態であるために異常低温が発生した場合でも、電磁弁の開閉を制御する電磁弁制御回路からの出力によって電磁弁を挟まった異物を振り落とすように一定時間毎に繰り返して開閉動作を与えることで、異物の除去ができるため、電磁弁を完全に閉じることができるとともに、異常低温状態の継続を防止できる。
【００３４】
第２に、電磁弁制御回路への制御装置からの出力は、該制御装置から警報器への出力と同時に行うことにより、異常低温発生時には電磁弁の開閉制御を確実に行うことができ、また、電磁弁制御回路からの出力による電磁弁の開閉制御は異常低温発生時のみすることで、設定温度の下限値以下になった場合は制御装置からの出力で直接制御することもできるものである。
【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…電磁弁
５…警報器
６…電磁弁制御回路[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a temperature control device for controlling the temperature inside a refrigerator-freezer open showcase.
[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. The control device controls the opening and closing of an electromagnetic valve provided in the middle of the refrigerant pipe for sending the refrigerant to the heat exchanger based on the value of the temperature in the refrigerator.
[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 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 provided with a solenoid valve 4 for turning on and off the supply of a refrigerant, and a low temperature generation device. An alarm 5 for notifying by sound or light is 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 outputs a control signal to the temperature control device so that the inside temperature falls within a temperature range of the control target temperature, which is the set temperature, by comparing the set inside temperature with the control target temperature set by the setting device 2. Control.
[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 5, and the alarm device 5 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 unit 2 and its differential, low temperature alarm temperature value, low temperature alarm time, etc. [Step (A)], and based on these values, the upper limit value of the set temperature. And the lower limit are calculated [step (a)], and the low temperature alarm temperature is 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 internal temperature is higher than the set temperature upper limit value, a signal for turning on the solenoid valve 4 is output from the control device 3 to the solenoid valve 4. [Step (f)], the electromagnetic valve 4 is opened, 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.
[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, a signal for turning off the solenoid valve 4 is output from the control device 3 to the solenoid valve 4. [Step (h)], the solenoid valve 4 is closed, the amount of refrigerant supplied to the cooler is reduced, the cooling capacity is reduced, and the internal temperature is controlled to be in the range of the control target temperature.
[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 solenoid valve 4 is closed in the step (C), 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, an abnormality is detected. It is determined that the low temperature has not occurred, and the count of the low temperature alarm time is reset [Step (S)], the low temperature alarm is released [Step (S)], and reading of the temperature measurement value is restarted [Step (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 5 (step (c)). , A low temperature alarm is issued by the alarm 5.
[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 solenoid valve 4 is turned on / off to control the measured temperature to fall within the range of the control target temperature. Further, if the temperature is lower than the low-temperature warning temperature value, a warning is issued, and this is repeated.
[0015]
[Problems to be solved by the invention]
As described above, the control of the internal temperature is performed by turning on and off the solenoid valve, which is based on the premise that the solenoid valve can be turned on and off by the output of a control signal from the control device. However, in spite of outputting the OFF signal from the control device, if abnormal low temperature occurs while the solenoid valve itself remains open for some reason, there is no means to turn it off and close it. The abnormal low temperature could not be eliminated.
[0016]
An object of the present invention is to solve the above-described disadvantages of the conventional example, and when an abnormal low temperature occurs while the solenoid valve itself remains open for some reason despite the output of the OFF signal from the control device. Another object of the present invention is to provide a temperature control device for a freezer and refrigerated open showcase, which can add ON / OFF control of the solenoid valve even in such a situation by adding means for separately controlling the solenoid valve, thereby preventing occurrence of abnormally low temperature.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, the present invention firstly provides a product storage having a duct inside a showcase main body having an opening and a heat exchanger provided with a blower and a cooler, which is provided with a heat exchanger. A temperature control device disposed in a freezing and refrigeration open showcase in which a cold air circulation duct end faces above and below the opening as an outlet and a suction port of a cold air curtain. , A setting device for setting a control target temperature, a low-temperature alarm temperature and a low-temperature alarm time, and the temperature measuring device and the setting device are connected to the input side, and the temperature measuring device and the setting device are connected to each other. A control device for controlling the opening / closing operation of an electromagnetic valve provided in the middle of a refrigerant pipe for sending refrigerant to the heat exchange device so that the temperature in the refrigerator falls within the set temperature range based on the input, and the temperature was measured by the temperature measuring device. Temperature and setting Measured temperature is compared with the set in vessel temperature is below low alarm temperature, the temperature control device of the refrigerated open showcase and a control unit for outputting an alarm signal to the alarm device when the elapsed undertemperature alarm time Since the temperature in the refrigerator is at the low temperature alarm temperature, even after controlling the control device to close the solenoid valve to stop the circulation of the refrigerant, if the low temperature alarm is continued, the control device is connected to the output side of the control device. By providing an electromagnetic valve control circuit that repeatedly opens and closes the electromagnetic valve at regular intervals, for example, when the electromagnetic valve is closed, foreign matter is caught in the electromagnetic valve and the valve is not completely closed. Even when abnormal low temperature occurs, the opening and closing operation is repeatedly performed for a certain period of time so that the foreign matter caught in the solenoid valve is shaken off by the output from the solenoid valve control circuit that controls the opening and closing of the solenoid valve. In Rukoto, since it is the removal of foreign matter, it is possible to close the electromagnetic valve completely prevents the continuation of the abnormal low temperature.
[0018]
Second, the output from the control device to the solenoid valve control circuit is performed simultaneously with the output from the control device to the alarm device, so that the opening and closing control of the solenoid valve can be reliably performed when abnormal low temperature occurs. By controlling the opening and closing of the solenoid valve by the output from the solenoid valve control circuit only when an abnormally low temperature occurs, when the temperature falls below the lower limit value of the set temperature, it can be directly controlled by the output from the control device.
[0019]
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. .
[0020]
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 and a low-temperature warning 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 provided with an electromagnetic valve 4 for turning on and off the supply of refrigerant and a low-temperature generation. At times, an alarm 5 for notifying this by sound or light is connected.
[0021]
In the present invention, in addition to the above configuration, as means for controlling the opening and closing of the solenoid valve 4 when a low temperature abnormality occurs, the solenoid valve control circuit 6 for controlling the opening and closing of the solenoid valve 4 at regular intervals is provided by the control device 3 and the solenoid valve 4. The output from the control circuit 3 was introduced to the solenoid valve 4 via the solenoid valve control circuit 6.
[0022]
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.
[0023]
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 set values such as the differential, the low-temperature alarm temperature value, and the low-temperature alarm time are controlled. The data is read by the 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 calculated [Step (C)].
[0024]
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)].
[0025]
As a result of the comparison, when the measured value is larger than the upper limit value, that is, when the measured internal temperature is higher than the set temperature upper limit value, a signal for turning on the solenoid valve 4 is output from the control device 3 to the solenoid valve 4. [Step (f)], the electromagnetic valve 4 is opened, 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.
[0026]
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)].
[0027]
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 for turning off the solenoid valve 4 is output from the control device 3 to the solenoid valve 4. [Step (h)], the solenoid valve 4 is closed, the amount of refrigerant supplied to the cooler is reduced, the cooling capacity is reduced, and the internal temperature is controlled to be in the range of the control target temperature.
[0028]
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 solenoid valve 4 is closed in the step (C), 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, an abnormality is detected. It is determined that the low temperature has not occurred, and the count of the low temperature alarm time is reset [Step (S)], the low temperature alarm is released [Step (S)], and reading of the temperature measurement value is restarted [Step (Step (S)]). D)).
[0029]
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 5 (step (c)). , A low temperature alarm is issued by the alarm 5.
[0030]
At the same time, a signal is output from the control device 3 to the solenoid valve control circuit 6, from which a signal for closing the solenoid valve 4 is output to the solenoid valve 4 and the solenoid valve 4 is closed [step (S)]. Thereafter, the counting of the closing time of the solenoid valve 4 is started [Step (T)]. When the closing time of the solenoid valve 4 reaches the set time [Step (H)], the counting of the closing time of the solenoid valve 4 is reset. [Step (T)], a signal to open the solenoid valve 4 is output from the solenoid valve control circuit 6 [Step (T)], the solenoid valve 4 is opened, and the counting of the opening time of the solenoid valve 4 is started. [Step (g)].
[0031]
When the opening time of the solenoid valve 4 reaches the set time [step (n)], the count of the opening time of the solenoid valve 4 is reset [step (d)], and a signal for closing the solenoid valve 4 is transmitted to the electromagnetic valve. The signal is output from the valve control circuit 6 [step (nu)] and the solenoid valve 4 is closed.
[0032]
When the low-temperature alarm is thus issued, the solenoid valve 4 is simultaneously opened and closed by the output from the solenoid valve control circuit 6 at regular intervals so that the measured value of the internal temperature does not fall below the low-temperature alarm temperature. Control.
[0033]
【The invention's effect】
As described above, the temperature control device for a freezer and refrigerated open showcase of the present invention is, first, a product storage that is connected to the opening by a duct plate inside the showcase body having the opening, a blower and a cooler. And a cooling air circulation duct in which a heat exchanger is provided, and the temperature of the cooling air circulation duct is arranged in a freezing and refrigeration open showcase in which the ends of the cooling air circulation duct face upward and downward of the opening as an outlet and an inlet of a cool air curtain. A control device, a temperature measuring device for measuring the temperature in the refrigerator, a control target temperature, a setting device for setting a low temperature alarm temperature and a low temperature alarm time, and the temperature measuring device and the setting device are connected to an input side. A control device that controls the opening and closing operation of an electromagnetic valve provided in the middle of a refrigerant pipe that sends a refrigerant to a heat exchange device so that the internal temperature falls within a set temperature range based on inputs from the temperature measuring device and the setting device. A control device that compares the temperature measured by the temperature measuring device with the temperature set in the setting device and outputs a warning signal to the alarm device when the measured temperature is equal to or lower than the low-temperature alarm temperature and the low-temperature alarm time has elapsed. In the temperature control device of the freezing and refrigeration open showcase provided with, since the temperature in the refrigerator is at the low-temperature alarm temperature, the low-temperature alarm is continued even after controlling the electromagnetic valve to close to stop the circulation of the refrigerant by the control device. When the solenoid valve is connected to the output side of the control device and the solenoid valve control circuit repeatedly opens and closes the solenoid valve at regular time intervals, for example, when the solenoid valve is closed, foreign matter is caught in the solenoid valve. Even if abnormal low temperature occurs because the valve is not completely closed, the foreign matter that caught the solenoid valve is shaken off by the output from the solenoid valve control circuit that controls the opening and closing of the solenoid valve Uni By providing the opening and closing operation is repeated at regular intervals, since it is the removal of foreign matter, it is possible to close the electromagnetic valve completely prevents the continuation of the abnormal low temperature.
[0034]
Second, the output from the control device to the solenoid valve control circuit is performed at the same time as the output from the control device to the alarm, so that the opening and closing control of the solenoid valve can be reliably performed when abnormal low temperature occurs. By controlling the opening and closing of the solenoid valve based on the output from the solenoid valve control circuit only when an abnormally low temperature occurs, when the temperature falls below the lower limit of the set temperature, it can be directly controlled by the output from the control device. .
[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 ... Solenoid valve 5 ... Alarm device 6 ... Solenoid valve control circuit

Claims

The inside 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 in which a heat exchanger including a blower and a cooler is provided, and the end of the cool air circulation duct is cooled by a cool air. A temperature control device disposed in a freezer and refrigeration open showcase that faces above and below the opening as an air curtain outlet and a suction port, and includes a temperature measuring device for measuring a temperature in a refrigerator, a control target temperature, and a low temperature alarm. A setting device for setting a temperature and a low-temperature alarm time, and the temperature measuring device and the setting device are connected to an input side so that the temperature in the refrigerator falls within a set temperature range based on inputs from the temperature measuring device and the setting device. In addition, a control device that controls the opening and closing operation of an electromagnetic valve provided in the middle of a refrigerant pipe that sends refrigerant to the heat exchange device, and compares the temperature measured by the temperature measuring device with the temperature set in the setting device. Measurement temperature A temperature control device for an open showcase having a temperature lower than the low-temperature alarm temperature and which outputs an alarm signal to the alarm device when the low-temperature alarm time elapses. Even after controlling to stop the circulation of the refrigerant by closing the electromagnetic valve by the device, if the low temperature alarm is continued, it is connected to the output side of the control device, and repeatedly opens and closes the electromagnetic valve at regular intervals. A temperature control device for a freezer and refrigerated open showcase, comprising a solenoid valve control circuit.

2. The temperature control device according to claim 1, wherein the output from the control device to the solenoid valve control circuit is performed simultaneously with the output from the control device to the alarm device.