JP4318369B2 - Screw type refrigerator - Google Patents

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Publication number
JP4318369B2
JP4318369B2 JP2000047448A JP2000047448A JP4318369B2 JP 4318369 B2 JP4318369 B2 JP 4318369B2 JP 2000047448 A JP2000047448 A JP 2000047448A JP 2000047448 A JP2000047448 A JP 2000047448A JP 4318369 B2 JP4318369 B2 JP 4318369B2
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temperature
compressor
screw
winding
continuous operation
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JP2001241787A (en
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和幸 塚本
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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【０００１】
【発明の属する技術分野】
この発明は半密閉構造および密閉構造のスクリュー式圧縮機を搭載した冷凍機に関する。
【０００２】
【従来の技術】
図４は従来のスクリュー冷凍機の冷媒回路図である。図において、１は電動部１ａと圧縮動作をするスクリューロータ部１ｂとから成るスクリュー式圧縮機、２は冷却水管２ａと熱交換し凝縮作用をする水式熱交換器、３は膨張弁、４はブライン配管５と熱交換し蒸発作用をするブライン熱交換器で、前記スクリュー式圧縮機１、水式熱交換器２および膨張弁３等と共に冷媒配管６により連結されて冷媒回路を構成している。７は制御装置で、前記ブライン配管５の入口管５ａ温度を検出するブライン入口温度検出装置７ａ、および前記スクリュー式圧縮機１の電動部１ａに設置され、巻線温度を検出する巻線保護用サーモスタット７ｂを備えている。
【０００３】
次に、動作について説明する。図に示すように、スクリュー式圧縮機１、水式熱交換器２、膨張弁３、ブライン熱交換器４および冷媒配管６により接続して冷媒回路を構成した冷凍機において、この冷凍機は、ブライン入口温度検出装置７ａにより検出されるブライン入口温度が制御装置７に伝えられ、制御装置７によって、冷凍機の冷媒容量調節を行う。
【０００４】
この容量調節はブライン入口温度信号を受けた制御装置７により制御する。冷凍機は、ブライン入口温度に応じ容量制御を行うが、負荷が減少しブライン入口温度が制御目標温度以下となり、サーモ停止設定温度まで達すると、サーモ停止となり自動的に圧縮機は停止となる。この後、負荷が上昇し、ブライン入口温度がサーモ復帰温度まで上昇すると、再度圧縮機の運転を開始する。
【０００５】
また、図５は、特開平８−２９１９４６号公報に示された従来のスクリュー式冷凍機の冷媒回路図である。図において、１はスクリュー圧縮機、２は外気と熱交換させ冷媒を凝縮させる空気熱交換器、４は冷水管５の冷水と熱交換し冷媒を蒸発させる水熱交換器、７は制御装置で、前記冷水管５出口管５ｂ温度を検知する冷水温度検知装置７ａと、前記空気熱交換器入口管２ａの温度を検知する凝縮温度検知装置２ｂ、前記スクリュー圧縮機１の冷媒吐出管６ａの凝縮圧力を検知する第１凝縮圧力検知装置２ｃおよび、前記空気熱交換器２の冷媒出口管６ｂの凝縮圧力を検知する第２凝縮圧力検知装置２ｄを備えている。８は四方弁、９は前記空気熱交換器２に外気を送りこむファン、１０はファン回転数を制御するインバータ、１１は電磁弁である。
【０００６】
次に、このように構成された第２の従来例のスクリュー式冷凍機の動作を説明する。２つの電磁弁１１を有するスクリュー圧縮機１、ファン９を有する空気熱交換器２、水式熱交換器４、及びそれらを冷媒配管５で接続して回路を形成するスクリュー冷凍機において、制御装置７は、スクリュー圧縮機１の冷媒吐出管６ａの凝縮圧力を検出する第１凝縮圧力検知装置２ｃおよび空気熱交換器２の冷媒出口管６ｂの凝縮圧力を検知する第２凝縮圧力検知装置２ｄによりそれぞれ凝縮圧力を検出して凝縮圧力が所定値（これを第一の設定値とする）になるように、空気熱交換器用のファン８を制御する。
【０００７】
また、冷水管５出口管５ｂ温度を検出して冷水温度が所定値になるように、圧縮機１を容量制御し、かつ第１凝縮圧力検知装置２ｃおよび第２凝縮圧力検知装置２ｅの凝縮圧力に前記第一の設定値より上に第二の設定値を設け、この第二の設定値によって、圧縮機１の容量制御を、冷水管５出口管５ｂ温度による制御に優先して圧縮機１のロード電磁弁１０又はアンロード電磁弁１０を制御するものである。
【０００８】
【発明が解決しようとする課題】
これら、従来のスクリュー式冷凍機は、以上のように構成されているので、負荷が減少し、サーモ停止した場合、ブライン入口温度がサーモ復帰設定温度まで上昇せねば運転を再開せず、負荷の急激な上昇に対応できないという問題があった。
【０００９】
この発明は上記の問題を解決するためになされたもので、電動機へ複数の巻線サーモスタットを備えた圧縮機を使用し、負荷の減少に伴い圧縮機の吸込み冷媒ガス量が減少したことを、電動機巻線温度の上昇により検知し、サーモ停止を回避制御することによって、冷凍機の連続運転を行い、負荷の急増にも遅滞なく対応でき、かつブライン出口温度の安定した安価なスクリュー冷凍機を提供することを目的とする。
【００１０】
【課題を解決するための手段】
この発明のスクリュー式冷凍機は、電動機部と圧縮動作をするスクリューロータ部とから成るスクリュー式圧縮機、水式熱交換器、ブライン配管を有するブライン熱交換器および膨張弁を冷媒配管により連結接続した冷媒回路と、前記スクリュー式圧縮機の電動機巻線温度の異常上昇を検知して圧縮機を保護する巻線保護用サーモスタット等の巻線保護手段とを備えたスクリュー式冷凍機において、前記巻線保護手段とは検知温度を異にして電動機巻線温度の巻線保護設定温度より低く設定した圧縮機連続運転温度を検知し圧縮機連続運転を継続させる圧縮機連続運転手段と、前記圧縮機連続運転手段の信号により冷凍機の連続運転を制御する制御手段と、を備え、前記圧縮機連続運転手段が前記圧縮機連続運転温度を検知し、前記巻線保護手段が前記巻線保護設定温度を検知していない状態となった場合には、前記制御手段は、前記スクリュー式圧縮機の運転容量を増大させるものである。
【００１１】
また、この発明のスクリュー式冷凍機は、電動機部と圧縮動作をするスクリューロータ部とから成るスクリュー式圧縮機、水式熱交換器、ブライン配管を有するブライン熱交換器および膨張弁を冷媒配管により連結接続した冷媒回路と、前記スクリュー式圧縮機の電動機巻線温度の異常上昇を検知して圧縮機を保護する巻線保護用サーモスタット等の巻線保護手段とを備えたスクリュー式冷凍機において、ブライン配管の出口管温度を検知するブライン出口温度検出手段と、前記巻線保護手段とは検知温度を異にして電動機巻線温度の巻線保護設定温度より低く設定した温度を検知し圧縮機連続運転を継続させる圧縮機連続運転手段を設けた制御手段を備え、前記ブライン配管の出口管温度が所定の設定温度以下となって、前記スクリュー式圧縮機の運転容量を減少させた際、前記圧縮機連続運転手段が前記圧縮機連続運転温度を検知し、前記巻線保護手段が前記巻線保護設定温度を検知していない状態となった場合には、前記制御手段は、前記スクリュー式圧縮機の運転容量を増大させるものである。
【００１２】
【発明の実施の形態】
実施の形態１．
以下、図１はこの発明の実施の形態１によるスクリュー式冷凍機を示す冷媒回路図である。図において、１は電動部１ａと圧縮動作をするスクリューロータ部１ｂとから成るスクリュー式圧縮機、２は冷却水管２ａと熱交換する水式熱交換器、３は膨張弁、４はブライン配管５と熱交換するブライン熱交換器で、前記スクリュー式圧縮機１、水式熱交換器２および膨張弁３等と共に冷媒配管６により連結されて冷媒回路を構成している。
【００１３】
７は制御装置で、前記ブライン配管の出口管５ｂ温度を検出し、圧縮機運転容量を連続的に低下させるブライン出口温度検出装置７ｃ、および前記スクリュー式圧縮機１の電動部１ａに設置され、巻線温度を検出し保護する巻線保護手段である、例えば１０５℃で巻線保護動作するよう設定された巻線保護用サーモスタット７ｂおよびこの巻線保護手段の設定温度よりは低く、かつスクリュー式圧縮機を連続運転させる設定温度、例えば７０℃から９０℃の範囲内の温度で連続運転を継続させる圧縮機連続運転手段である圧縮機連続運転用サーモスタット７ｄを備えている。
【００１４】
次に、動作について説明する。冷凍機負荷側の要求能力が低下するにしたがって、ブラインの出入口温度差が減少する。ブライン出口温度検出装置７ｃによりブライン出口温度を検知し、この検出信号により制御装置７が、圧縮機運転容量を絞りこみ圧縮機１の運転容量を連続的に低下させる。この制御により冷凍機の冷媒循環量が低下する。この圧縮機を駆動する電動機は冷凍機を循環する冷媒ガスにより冷却されている。そのため、冷媒循環量が低下すると、必然的に電動機の冷却効果が低下し電動機の温度を上昇させることとなる。
【００１５】
この時、電動機１ａの巻線温度上昇限界の巻線保護温度を、例えば１０５℃に設定しておき、また、この巻線温度上昇温度より余裕を持たせた圧縮機連続運転設定温度である、例えば７０℃から９０℃の範囲の設定温度で作動するスクリュー式圧縮機連続運転用サーモスタット７ｄが作動し、この信号をうけて圧縮機１を連続運転させて圧縮機１の運転容量を上昇させる。
【００１６】
次に、図２に示すスクリュー式冷凍機の制御フローチャートを説明する。図において、始めに、ステップ１０１において、冷凍機の運転を開始する。運転開始後ステップ１０２に進む。ステップ１０２では、ブライン配管のブライン出口検出温度ＴAがブライン出口設定温度ＴBと同じか小さい場合は、ステップ１０３に進み、圧縮機の運転容量を減少させる。又、ステップ１０２で、ブライン配管のブライン出口検出温度ＴAがブライン出口設定温度ＴBより大きい場合は、ステップ１０５に進み、圧縮機の運転容量を増大させる。ステップ１０３で運転容量を減少させ冷凍機の冷媒循環量を低下させると、必然的に電動機巻線の冷却効果が低下し電動機巻線温度は上昇する。
【００１７】
ステップ１０４で、圧縮機用電動機の巻線温度Ｔが低温度側巻線サーモスタット設定温度ＴLと等しいか、又は圧縮機用電動機の巻線温度Ｔが低温度側巻線サーモスタット設定温度ＴLより大な場合は、ステップ１０５に進み、圧縮機の運転容量を増大させる。、ステップ１０５で圧縮機の運転容量を増大させ冷媒循環量を上昇させた後、ステップ１０６で圧縮機用電動機の巻線温度Ｔが低温度側巻線サーモスタット設定温度ＴLより小なる場合は、ステップ１０１に戻って当初の冷凍機容量での運転を始める。又、ステップ１０６で圧縮機用電動機の巻線温度Ｔが低温度側巻線サーモスタット設定温度ＴLより小でない場合は、ステップ１０７で圧縮機用電動機の巻線温度Ｔが高温度側巻線サーモスタット設定温度ＴHと等しいか、又は圧縮機用電動機の巻線温度Ｔが高温度側巻線サーモスタット設定温度ＴHより大なる場合は、ステップ１０８に進み冷凍機の運転を停止する。又、ステップ１０７で圧縮機用電動機の巻線温度Ｔが高温度側巻線サーモスタット設定温度ＴHより小なる場合は、ステップ１０５に戻り圧縮機の運転容量を増大させる運転をする。
【００１８】
次に、図３に示す圧縮機容量制御特性図により圧縮機の運転容量と冷媒循環量との関係を説明する。この場合の運転条件は、凝縮温度／蒸発温度は一定とする。図において、圧縮機運転容量を低下させた場合、冷媒循環量の低下率は電気入力の低下率より大きい。逆に、圧縮機運転容量を増大させた場合、冷媒循環量の増大率は、電気入力の増大率より大きい。そのため、容量制御運転時に電動機温度が上昇した場合、圧縮機の運転容量を増大させることで、電動機の冷却効果を増大させることができる。即ち、冷媒循環量と電気入力との交点Ｐ以上では電動機の冷却が良好に促進されるが、交点Ｐ以下では冷却不足となり冷却効果は期待できない。
【００１９】
【発明の効果】
以上に述べたように、この発明のスクリュー式冷凍機は、電動機部と圧縮動作をするスクリューロータ部とから成るスクリュー式圧縮機、水式熱交換器、ブライン配管を有するブライン熱交換器および膨張弁を冷媒配管により連結接続した冷媒回路と、前記スクリュー式圧縮機の電動機巻線温度の異常上昇を検知して圧縮機を保護する巻線保護用サーモスタット等の巻線保護手段とを備えたスクリュー式冷凍機において、前記巻線保護手段とは検知温度を異にして電動機巻線温度の巻線保護設定温度より低く設定した圧縮機連続運転温度を検知し圧縮機連続運転を継続させる圧縮機連続運転手段と、前記圧縮機連続運転手段の信号により冷凍機の連続運転を制御する制御手段と、を備え、前記圧縮機連続運転手段が前記圧縮機連続運転温度を検知し、前記巻線保護手段が前記巻線保護設定温度を検知していない状態となった場合には、前記制御手段は、前記スクリュー式圧縮機の運転容量を増大させる構成としたから、圧縮器の連続運転を可能にし、負荷の急変にも迅速に追従する運転制御ができ、かつ冷凍機の容量制御を安価に実現できる効果を有する。
【００２０】
また、この発明のスクリュー式冷凍機は、電動機部と圧縮動作をするスクリューロータ部とから成るスクリュー式圧縮機、水式熱交換器、ブライン配管を有するブライン熱交換器および膨張弁を冷媒配管により連結接続した冷媒回路と、前記スクリュー式圧縮機の電動機巻線温度の異常上昇を検知して圧縮機を保護する巻線保護用サーモスタット等の巻線保護手段とを備えたスクリュー式冷凍機において、ブライン配管の出口管温度を検知するブライン出口温度検出手段と、前記巻線保護手段とは検知温度を異にして電動機巻線温度の巻線保護設定温度より低く設定した温度を検知し圧縮機連続運転を継続させる圧縮機連続運転手段を設けた制御手段を備え、前記ブライン配管の出口管温度が所定の設定温度以下となって、前記スクリュー式圧縮機の運転容量を減少させた際、前記圧縮機連続運転手段が前記圧縮機連続運転温度を検知し、前記巻線保護手段が前記巻線保護設定温度を検知していない状態となった場合には、前記制御手段は、前記スクリュー式圧縮機の運転容量を増大させる構成としたから、ブライン出口温度の安定した制御を可能とた安価な冷凍機を提供できる効果を有する。
【図面の簡単な説明】
【図１】 この発明の実施の形態によるスクリュー式冷凍機を示す冷媒回路図である。
【図２】 この発明の実施の形態によるスクリュー式冷凍機の制御フローチャート図である。
【図３】 この発明の実施の形態によるスクリュー式冷凍機の容量制御特性図である。
【図４】 従来のスクリュー式冷凍機を示す冷媒回路図である。
【図５】 第２の従来例のによるスクリュー式冷凍機を示す冷媒回路図である。
【符号の説明】
１ スクリュー圧縮機、１ａ 電動機、１ｂ スクリューロータ、２ 凝縮器、３ 膨張弁、４ 蒸発器、５ 冷媒配管、７ 制御装置、７ｂ 巻線保護手段、６ｃ 圧縮機連続運転手段。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigerator equipped with a screw-type compressor having a semi-hermetic structure and a hermetic structure.
[0002]
[Prior art]
FIG. 4 is a refrigerant circuit diagram of a conventional screw refrigerator. In the figure, 1 is a screw type compressor comprising an electric part 1a and a screw rotor part 1b that performs a compression operation, 2 is a water heat exchanger that exchanges heat with the cooling water pipe 2a and performs a condensing action, 3 is an expansion valve, 4 Is a brine heat exchanger that exchanges heat with the brine pipe 5 and evaporates, and is connected to the screw compressor 1, the water heat exchanger 2 and the expansion valve 3 by the refrigerant pipe 6 to form a refrigerant circuit. Yes. A control device 7 is installed in the brine inlet temperature detection device 7a for detecting the temperature of the inlet pipe 5a of the brine pipe 5 and the motor unit 1a of the screw compressor 1 for winding protection for detecting the winding temperature. A thermostat 7b is provided.
[0003]
Next, the operation will be described. As shown in the figure, in a refrigerator that is connected by a screw compressor 1, a water heat exchanger 2, an expansion valve 3, a brine heat exchanger 4 and a refrigerant pipe 6 to form a refrigerant circuit, the refrigerator is The brine inlet temperature detected by the brine inlet temperature detection device 7a is transmitted to the control device 7, and the control device 7 adjusts the refrigerant capacity of the refrigerator.
[0004]
This capacity adjustment is controlled by the control device 7 that has received the brine inlet temperature signal. The refrigerator performs capacity control according to the brine inlet temperature. However, when the load decreases, the brine inlet temperature becomes equal to or lower than the control target temperature, and reaches the thermo-stop set temperature, the thermo-stop occurs and the compressor is automatically stopped. Thereafter, when the load increases and the brine inlet temperature rises to the thermo return temperature, the operation of the compressor is started again.
[0005]
FIG. 5 is a refrigerant circuit diagram of a conventional screw type refrigerator disclosed in Japanese Patent Laid-Open No. 8-291946. In the figure, 1 is a screw compressor, 2 is an air heat exchanger that exchanges heat with the outside air and condenses the refrigerant, 4 is a water heat exchanger that exchanges heat with cold water in the cold water pipe 5 and evaporates the refrigerant, and 7 is a control device. The cold water temperature detection device 7a for detecting the temperature of the cold water pipe 5 outlet tube 5b, the condensation temperature detection device 2b for detecting the temperature of the air heat exchanger inlet pipe 2a, and the condensation of the refrigerant discharge pipe 6a of the screw compressor 1 A first condensing pressure detecting device 2c for detecting pressure and a second condensing pressure detecting device 2d for detecting the condensing pressure of the refrigerant outlet pipe 6b of the air heat exchanger 2 are provided. 8 is a four-way valve, 9 is a fan for sending outside air to the air heat exchanger 2, 10 is an inverter for controlling the number of fan rotations, and 11 is a solenoid valve.
[0006]
Next, the operation of the screw refrigerator of the second conventional example configured as described above will be described. In a screw compressor 1 having two solenoid valves 11, an air heat exchanger 2 having a fan 9, a water heat exchanger 4, and a screw refrigerator that connects them with a refrigerant pipe 5 to form a circuit, a control device 7, the second condensing pressure detecting device for detecting a first condensing pressure sensing device 2c and the condensation pressure of the refrigerant outlet pipe 6 b of the air heat exchanger 2 for detecting the condensing pressure of the refrigerant discharge pipe 6a of the screw compressor 1 2 The condensing pressure is detected by d and the fan 8 for the air heat exchanger is controlled so that the condensing pressure becomes a predetermined value (this is the first set value).
[0007]
Further, the capacity of the compressor 1 is controlled so that the temperature of the chilled water pipe 5 outlet pipe 5b is detected and the chilled water temperature becomes a predetermined value, and the condensing pressure of the first condensing pressure detecting device 2c and the second condensing pressure detecting device 2e. The second set value is provided above the first set value, and the compressor 1 is given priority over the control of the capacity of the compressor 1 by the temperature of the cold water pipe 5 outlet pipe 5b by the second set value. The load solenoid valve 10 or the unload solenoid valve 10 is controlled.
[0008]
[Problems to be solved by the invention]
Since these conventional screw refrigerators are configured as described above, when the load is reduced and the thermo is stopped, the operation is not resumed unless the brine inlet temperature rises to the thermo return set temperature. There was a problem that it could not cope with the rapid rise.
[0009]
This invention was made in order to solve the above-mentioned problem, using a compressor equipped with a plurality of winding thermostats in an electric motor, and that the amount of refrigerant gas sucked in the compressor decreased with a decrease in load. By detecting the increase in the motor winding temperature and controlling to avoid stopping the thermostat, the refrigerator can be operated continuously, can respond to sudden increases in load without delay, and an inexpensive screw refrigerator with stable brine outlet temperature. The purpose is to provide.
[0010]
[Means for Solving the Problems]
The screw type refrigerator of the present invention includes a screw compressor comprising a motor part and a screw rotor part that performs a compression operation, a water heat exchanger, a brine heat exchanger having a brine pipe, and an expansion valve connected by refrigerant piping. In the screw type refrigerator comprising the above-described refrigerant circuit and winding protection means such as a winding protection thermostat for detecting an abnormal increase in the motor winding temperature of the screw compressor and protecting the compressor. Compressor continuous operation means for detecting a compressor continuous operation temperature which is lower than the winding protection set temperature of the motor winding temperature, different from the line protection means, and continuing the compressor continuous operation, and the compressor and a control means by a signal of continuous operation means for controlling the continuous operation of the refrigerator, and the compressor continuous operation means detects the compressor continuous operating temperature, protected the winding If the stage is a state does not detect the winding protection set temperature, said control means is to increase the operating capacity of the screw compressor.
[0011]
The screw refrigerator of the present invention includes a screw compressor comprising a motor section and a screw rotor section that performs a compression operation, a water heat exchanger, a brine heat exchanger having a brine pipe, and an expansion valve by a refrigerant pipe. In a screw type refrigerator having a coupled refrigerant circuit and winding protection means such as a winding protection thermostat for detecting an abnormal increase in the motor winding temperature of the screw compressor and protecting the compressor, The brine outlet temperature detecting means for detecting the outlet pipe temperature of the brine piping, and the winding protection means detect the temperature set lower than the winding protection set temperature of the motor winding temperature, and detect the temperature continuously. a control unit having a compressor continuous operation means to continue the operation, the outlet pipe temperature of the brine pipe is equal to or less than the predetermined set temperature, the screw When the operation capacity of the compressor is reduced, the compressor continuous operation means detects the compressor continuous operation temperature, and the winding protection means has not detected the winding protection set temperature. The control means increases the operating capacity of the screw compressor .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a refrigerant circuit diagram showing a screw type refrigerator according to Embodiment 1 of the present invention. In the figure, 1 is a screw type compressor composed of an electric part 1a and a screw rotor part 1b that performs a compression operation, 2 is a water heat exchanger that exchanges heat with a cooling water pipe 2a, 3 is an expansion valve, 4 is a brine pipe 5 This is a brine heat exchanger that exchanges heat with the screw compressor 1, the water heat exchanger 2, the expansion valve 3, and the like, and is connected by a refrigerant pipe 6 to constitute a refrigerant circuit.
[0013]
7 is a control device, which is installed in the brine outlet temperature detection device 7c for detecting the temperature of the outlet pipe 5b of the brine pipe and continuously reducing the compressor operating capacity, and the electric part 1a of the screw compressor 1. Winding protection means for detecting and protecting the winding temperature, for example, a winding protection thermostat 7b set to perform a winding protection operation at 105 ° C., and a screw type lower than the set temperature of the winding protection means A compressor continuous operation thermostat 7d, which is a compressor continuous operation means for continuing the continuous operation at a set temperature for continuously operating the compressor, for example, a temperature within a range of 70 ° C. to 90 ° C., is provided.
[0014]
Next, the operation will be described. As the required capacity on the refrigerator load side decreases, the inlet / outlet temperature difference of the brine decreases. The brine outlet temperature detection device 7c detects the brine outlet temperature, and the control device 7 squeezes the compressor operating capacity by this detection signal to continuously reduce the operating capacity of the compressor 1. This control reduces the refrigerant circulation rate of the refrigerator. The electric motor that drives the compressor is cooled by the refrigerant gas circulating in the refrigerator. For this reason, when the refrigerant circulation amount is reduced, the cooling effect of the electric motor is inevitably reduced and the temperature of the electric motor is increased.
[0015]
At this time, the winding protection temperature at the winding temperature rise limit of the electric motor 1a is set to 105 ° C., for example, and is the compressor continuous operation set temperature with a margin from the winding temperature rise temperature. For example, a screw compressor continuous operation thermostat 7d that operates at a set temperature in the range of 70 ° C. to 90 ° C. operates, and receives this signal to continuously operate the compressor 1 to increase the operation capacity of the compressor 1.
[0016]
Next, a control flowchart of the screw refrigerator shown in FIG. 2 will be described. In the figure, first, in step 101, the operation of the refrigerator is started. Proceed to step 102 after the start of operation. In step 102, if the brine outlet detected temperature T A of the brine pipe is less than or equal brine outlet set temperature T B, the process proceeds to step 103, reducing the operating capacity of the compressor. Further, in step 102, if the brine outlet detected temperature T A of the brine pipe is greater than the brine outlet set temperature T B, the process proceeds to step 105, to increase the operating capacity of the compressor. If the operating capacity is reduced in step 103 and the refrigerant circulation amount of the refrigerator is reduced, the cooling effect of the motor winding is inevitably reduced and the motor winding temperature rises.
[0017]
In step 104, the winding temperature T of the compressor motor is equal to the low temperature side winding thermostat set temperature TL , or the compressor motor winding temperature T is lower than the low temperature side winding thermostat set temperature TL . If so, the process proceeds to step 105 and the operating capacity of the compressor is increased. In Step 105, after increasing the operating capacity of the compressor and increasing the refrigerant circulation amount, in Step 106, if the winding temperature T of the compressor motor is lower than the low temperature side winding thermostat set temperature TL , Returning to step 101, operation at the initial refrigerator capacity is started. If the winding temperature T of the compressor motor is not lower than the low temperature side thermostat set temperature TL in step 106, the winding temperature T of the compressor motor is set to the high temperature side winding thermostat in step 107. or equal to the set temperature T H, or if winding temperature T of the compressor motor larger made of a high temperature winding thermostat set temperature T H stops the operation of the refrigerator proceeds to step 108. Moreover, winding temperature T of the compressor electric motor in step 107, if the small made of a high temperature winding thermostat set temperature T H, the operation of increasing the operating capacity of the compressor returns to step 105.
[0018]
Next, the relationship between the operating capacity of the compressor and the refrigerant circulation amount will be described with reference to the compressor capacity control characteristic diagram shown in FIG. The operating condition in this case is that the condensation temperature / evaporation temperature is constant. In the figure, when the compressor operating capacity is reduced, the rate of decrease in the refrigerant circulation rate is greater than the rate of decrease in electrical input. Conversely, when the compressor operating capacity is increased, the increase rate of the refrigerant circulation rate is greater than the increase rate of the electric input. Therefore, when the motor temperature rises during the capacity control operation, the cooling effect of the motor can be increased by increasing the operation capacity of the compressor. That is, the cooling of the motor is favorably promoted above the intersection P between the refrigerant circulation amount and the electric input, but the cooling effect is insufficient below the intersection P, and a cooling effect cannot be expected.
[0019]
【The invention's effect】
As described above, the screw-type refrigerator of the present invention includes a screw compressor including a motor portion and a screw rotor portion that performs a compression operation, a water heat exchanger, a brine heat exchanger having a brine pipe, and an expansion. Screw having a refrigerant circuit in which valves are connected and connected by refrigerant piping, and winding protection means such as a thermostat for winding protection that detects an abnormal rise in the motor winding temperature of the screw compressor and protects the compressor In the compressor type refrigerator, the compressor continuous operation for detecting the compressor continuous operation temperature which is lower than the winding protection set temperature of the motor winding temperature with the detection temperature being different from the winding protection means and continuing the compressor continuous operation. and operation means, and control means for controlling the continuous operation of the refrigerator by a signal of the compressor continuous operation means, said compressor continuous operation means the compressor continuous operating temperature And knowledge, when said winding protection means is in a state of not detecting the winding protection set temperature, the control means, from and configured to increase the operating capacity of the screw compressor, the compression This makes it possible to perform continuous operation of the refrigerator, to perform operation control that quickly follows sudden changes in load, and to achieve capacity control of the refrigerator at low cost.
[0020]
The screw refrigerator of the present invention includes a screw compressor comprising a motor section and a screw rotor section that performs a compression operation, a water heat exchanger, a brine heat exchanger having a brine pipe, and an expansion valve by a refrigerant pipe. In a screw type refrigerator having a coupled refrigerant circuit and winding protection means such as a winding protection thermostat for detecting an abnormal increase in the motor winding temperature of the screw compressor and protecting the compressor, The brine outlet temperature detecting means for detecting the outlet pipe temperature of the brine piping, and the winding protection means detect the temperature set lower than the winding protection set temperature of the motor winding temperature, and detect the temperature continuously. a control unit having a compressor continuous operation means to continue the operation, the outlet pipe temperature of the brine pipe is equal to or less than the predetermined set temperature, the screw When the operation capacity of the compressor is reduced, the compressor continuous operation means detects the compressor continuous operation temperature, and the winding protection means has not detected the winding protection set temperature. In addition, since the control means is configured to increase the operating capacity of the screw compressor , it has an effect of providing an inexpensive refrigerator capable of stably controlling the brine outlet temperature.
[Brief description of the drawings]
FIG. 1 is a refrigerant circuit diagram showing a screw refrigerator according to an embodiment of the present invention.
FIG. 2 is a control flowchart of the screw refrigerator according to the embodiment of the present invention.
FIG. 3 is a capacity control characteristic diagram of the screw refrigerator according to the embodiment of the present invention.
FIG. 4 is a refrigerant circuit diagram showing a conventional screw refrigerator.
FIG. 5 is a refrigerant circuit diagram showing a screw refrigerator according to a second conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Screw compressor, 1a Electric motor, 1b Screw rotor, 2 Condenser, 3 Expansion valve, 4 Evaporator, 5 Refrigerant piping, 7 Control apparatus, 7b Winding protection means, 6c Compressor continuous operation means.

Claims (2)

電動機部と圧縮動作をするスクリューロータ部とから成るスクリュー式圧縮機、水式熱交換器、ブライン配管を有するブライン熱交換器および膨張弁を冷媒配管により連結接続した冷媒回路と、前記スクリュー式圧縮機の電動機巻線温度の異常上昇を検知して圧縮機を保護する巻線保護用サーモスタット等の巻線保護手段とを備えたスクリュー式冷凍機において、
前記巻線保護手段とは検知温度を異にして電動機巻線温度の巻線保護設定温度より低く設定した圧縮機連続運転温度を検知し圧縮機連続運転を継続させる圧縮機連続運転手段と、
前記圧縮機連続運転手段の信号により冷凍機の連続運転を制御する制御手段と、
を備え、
前記圧縮機連続運転手段が前記圧縮機連続運転温度を検知し、前記巻線保護手段が前記巻線保護設定温度を検知していない状態となった場合には、
前記制御手段は、
前記スクリュー式圧縮機の運転容量を増大させることを特徴とするスクリュー式冷凍機。A screw compressor composed of an electric motor section and a screw rotor section that performs compression operation, a water heat exchanger, a brine heat exchanger having a brine pipe, and a refrigerant circuit in which an expansion valve is connected by a refrigerant pipe, and the screw compression In a screw type refrigerator equipped with winding protection means such as a winding protection thermostat for detecting an abnormal rise in the motor winding temperature of the machine and protecting the compressor,
Compressor continuous operation means for detecting the compressor continuous operation temperature that is set lower than the winding protection set temperature of the motor winding temperature by differently detecting the winding temperature and continuing the compressor continuous operation ,
Control means for controlling the continuous operation of the refrigerator by a signal of the compressor continuous operation means ;
With
When the compressor continuous operation means detects the compressor continuous operation temperature and the winding protection means has not detected the winding protection set temperature,
The control means includes
An operating capacity of the screw compressor is increased . 電動機部と圧縮動作をするスクリューロータ部とから成るスクリュー式圧縮機、水式熱交換器、ブライン配管を有するブライン熱交換器および膨張弁を冷媒配管により連結接続した冷媒回路と、前記スクリュー式圧縮機の電動機巻線温度の異常上昇を検知して圧縮機を保護する巻線保護用サーモスタット等の巻線保護手段とを備えたスクリュー式冷凍機において、
ブライン配管の出口管温度を検知するブライン出口温度検出手段と、前記巻線保護手段とは検知温度を異にして電動機巻線温度の巻線保護設定温度より低く設定した圧縮機連続運転温度を検知し圧縮機連続運転を継続させる圧縮機連続運転手段を設けた制御手段を備え、
前記ブライン配管の出口管温度が所定の設定温度以下となって、前記スクリュー式圧縮機の運転容量を減少させた際、
前記圧縮機連続運転手段が前記圧縮機連続運転温度を検知し、前記巻線保護手段が前記巻線保護設定温度を検知していない状態となった場合には、
前記制御手段は、前記スクリュー式圧縮機の運転容量を増大させることを特徴とするスクリュー式冷凍機。A screw compressor composed of an electric motor section and a screw rotor section that performs compression operation, a water heat exchanger, a brine heat exchanger having a brine pipe, and a refrigerant circuit in which an expansion valve is connected by a refrigerant pipe, and the screw compression In a screw type refrigerator equipped with winding protection means such as a winding protection thermostat for detecting an abnormal rise in the motor winding temperature of the machine and protecting the compressor,
The brine outlet temperature detection means for detecting the outlet pipe temperature of the brine piping and the winding protection means detect the compressor continuous operation temperature set lower than the winding protection set temperature of the motor winding temperature, with a different detection temperature. And a control means provided with a compressor continuous operation means for continuing the compressor continuous operation,
When the outlet pipe temperature of the brine pipe is equal to or lower than a predetermined set temperature and the operating capacity of the screw compressor is reduced,
When the compressor continuous operation means detects the compressor continuous operation temperature and the winding protection means has not detected the winding protection set temperature,
The screw type refrigerator is characterized in that the control means increases an operating capacity of the screw compressor .
JP2000047448A 2000-02-24 2000-02-24 Screw type refrigerator Expired - Lifetime JP4318369B2 (en)

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JP4682683B2 (en) * 2005-04-27 2011-05-11 株式会社豊田自動織機 Electric motor control device for electric compressor
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JPS6273058A (en) * 1985-09-26 1987-04-03 三洋電機株式会社 Refrigerator
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