JP4068778B2

JP4068778B2 - Refrigeration system

Info

Publication number: JP4068778B2
Application number: JP2000024967A
Authority: JP
Inventors: 正博西原; 達二宮
Original assignee: TOYO. SS. CO., LTD.
Current assignee: TOYO. SS. CO., LTD.
Priority date: 2000-02-02
Filing date: 2000-02-02
Publication date: 2008-03-26
Anticipated expiration: 2020-02-02
Also published as: JP2001215065A

Description

【０００１】
【発明の属する技術分野】
本発明は環境試験装置等における空気調和用に好適な乾式冷却方式の冷凍システムに関する。
【０００２】
【従来の技術とその問題点】
環境試験室内の温度を変化させて各種のテストを行う環境試験装置の冷凍システムには乾式冷却方式のものがあり、この冷凍システムとヒータとで試験室内を所要の温度に冷却あるいは加温する構成となっている。
【０００３】
このような環境試験装置においては、試験室内の室温を低温から高温へ変化させる際、冷凍システムにおける圧縮機の吸入側に設けられた蒸発圧力調整弁を閉じて蒸発器内の蒸発圧力を上昇させることにより、蒸発器にて冷却を休止させるようになっている。
この際、蒸発圧力調整弁が閉ざされていることから冷媒管内には冷媒が流れず、したがって蒸発器の出口側における冷媒の温度は低温のままで圧力が上昇する。
【０００４】
ところで、冷凍システムの蒸発器入口側における膨張弁には、一般的に蒸発器出口側の冷媒の温度および圧力を検知する感温部を有する温度式膨張弁が使用される。
【０００５】
膨張弁は蒸発器出口側の冷媒温度が低温で圧力が高いことを検知し、冷却し過ぎと判断して閉じてしまう。さらに、室温を上昇させている間は膨張弁の閉止により冷媒が流れないので、蒸発器の出口側における冷媒の温度は上昇せず、膨張弁は冷却し過ぎと判断したまま開かれず、室温の上昇が完了しても冷却できない状態、すなわち試験室の温度を降下させることができなくなる。
【０００６】
上述の問題に対し、従来では室温を上昇させる際に室温が設定温度に達すると前記蒸発圧力調整弁を強制的に開き、蒸発圧力を降下させることによって膨張弁を開き、冷媒管内に冷媒を流通させることにより感温部の温度を変化させてから再度蒸発圧力調整弁を制御している。
【０００７】
しかし、蒸発圧力調整弁が強制的に開かれることにより蒸発器内における冷媒の蒸発圧力が一時的に制御できない状態となり、したがって試験室内の温度制御が乱れる。
【０００８】
【目的】
本発明の目的とするところは、冷却運転を休止した後に安定的かつ円滑に冷却運転の再開を行うことができる冷凍システムを提供することにある。
【０００９】
【本発明の構成】
上記目的を達成するために、本発明の請求項１に係る冷凍システムは、圧縮機の吐出口から被空調室内の乾式蒸発器の入口に到る冷媒往管に凝縮器、温度式膨張弁が設けられ、前記乾式蒸発器の出口から前記圧縮機の吸入口に到る冷媒復管に蒸発圧力調整弁を有する冷凍システムにおいて、前記冷媒往管の凝縮器と膨張弁との間に一端を接続したバイパス管の他端を冷媒往管の膨張弁と蒸発器との間に接続し、同バイパス管の途中に、被空調室内の温度をヒータを用いて上昇させる際に被空調室内が設定温度に達すると所定時間開かれるバイパス開閉弁を設けてなる構成のものとしてある。
【００１０】
また、本発明の請求項２に係る冷凍システムは、圧縮機の吐出口から被空調室内の乾式蒸発器の入口に到る冷媒往管に凝縮器、温度式膨張弁が設けられ、前記乾式蒸発器の出口から前記圧縮機の吸入口に到る冷媒復管に蒸発圧力調整弁を有する冷凍システムにおいて、前記冷媒往管の凝縮器と膨張弁との間に一端を接続したバイパス管の他端を冷媒往管の膨張弁と蒸発器との間に接続し、同バイパス管の途中に、制御回路からの信号に基づいて開閉制御されるバイパス開閉弁を設け、前記制御回路は温度比較回路とタイマ回路とを備え、温度比較回路は前記被空調室内に設けた温度センサにより検知される室温と予め設定された設定温度とを比較し、被空調室内の温度をヒータを用いて上昇させる際に室温が設定温度に達すると温度比較回路が前記タイマ回路をＯＮならしめて前記バイパス開閉弁を開き、所定時間後にタイマ回路がＯＦＦになるとバイパス開閉弁が閉ざされる構成のものとしてある。
【００１１】
【実施例】
以下、本発明に係る冷凍システムの実施例を添付図面に示す具体例に基づいて詳細に説明する。
圧縮機１の吐出口に一端が接続された冷媒往管２の他端は、油分離器３、凝縮器４、膨張弁５を経て被空調室たる試験室６内に設けた空調器７内の乾式蒸発器８に接続されている。
【００１２】
同乾式蒸発器８に一端が接続された冷媒復管９の他端は蒸発圧力調整弁１０を介して前記圧縮機１の吸入口に接続されている。
【００１３】
前記膨張弁５は温度式膨張弁としてあって、その感温部５ａは蒸発器出口付近の前記冷媒復管９に設けられ、同冷媒復管９内の冷媒圧力を検知する均圧管５ｂの端部も前記冷媒復管の感温部近傍に接続されている。
なお、図中の符号１１は空調器のヒータ、１２は送風機を示している。
【００１４】
しかして、前記冷媒往管２の途中には、一端が前記凝縮器４と膨張弁５の間に接続され、他端が膨張弁５と蒸発器８の間に接続されて膨張弁５を跨ぐバイパス管１３を設けてあり、同バイパス管１３の途中にはバイパス開閉弁１４を設けてある。
【００１５】
このバイパス開閉弁１４は室温を上昇させる際に試験室６内の温度（室温）が予め設定された温度（設定温度）に達したときにだけ制御回路１５からの指令によって所定時間開かれ、その他の冷却運転時や冷却運転休止時には閉ざされている。
【００１６】
制御回路１５は温度比較回路とタイマとを備えていて、温度比較回路は試験室６内に設けた温度センサ１６により検知される室温と設定温度とを比較し、室温を上昇させる際に室温と設定温度が等しくなると温度比較回路からの信号によりタイマがＯＮとなって制御回路１５がバイパス開閉弁１４を開き、所定時間後にタイマがＯＦＦになると制御回路１５がバイパス開閉弁１４を閉じる。
なお、タイマがＯＮとなっている時間、すなわちバイパス開閉弁１４を開いておく時間は蒸発器８の容量、試験室６内の室温等の各種要素によって異なる。
【００１７】
次ぎに上述のように構成した本発明に係る冷凍システムの作用を説明する。
冷却運転時には、前記バイパス開閉弁１４が閉ざされていて、圧縮機１からの冷媒が冷媒往管２により油分離器３、凝縮器４および膨張弁５を経て蒸発器８内に流入し、送風機１２により空調器７内を流過する室内空気と熱交換する。そして蒸発器８からの冷媒は、冷媒往管９によって蒸発圧力調整弁１０を経て圧縮機へ戻される。
【００１８】
室内温度を上昇させる際には、ヒータ１１により空調器７を流過する室内空気を加温するとともに、冷凍システムにおいては蒸発圧力調整弁１０を閉じて蒸発器８内における冷媒の蒸発圧力を上昇させ、蒸発器における冷却を休止せしめる。
この際、膨張弁５は感温部５ａおよび均圧管５ｂにより、蒸発器８出口側における冷媒温度が低温、高圧であることを検知して閉ざされている。
【００１９】
その後、温度センサ１６により検知される試験室６内の温度が図２に示されるように予め設定された設定温度Ｔ_H に達すると、制御回路１５の温度比較回路がタイマをＯＮとして制御回路がバイパス開閉弁１４を開き、所定時間ｔが経過した後にタイマがＯＦＦになると制御回路がバイパス開閉弁１４を閉じる。
【００２０】
この際、冷媒往管２内の冷媒はバイパス管１３を流過して蒸発器８内に流れ込み、蒸発器内および同出口側における冷媒復管９内の冷媒温度が上昇し、膨張弁５が開かれ、冷却運転を再開することができる状態になる。
なお、この状態は室温を高温に保持し続ける場合であってもそのまま維持され、外部から冷却運転の指令を受けると直ちに冷却運転が行われる。
【００２１】
【発明の効果】
本発明に係る冷凍システムは、冷媒往管の途中に膨張弁を跨ぐバイパス管を備えているので、冷却運転を休止して温度式膨張弁が閉ざされても、被空調室内の温度が設定温度になると冷媒がバイパス管を経て蒸発器に流されるので、蒸発器出口における冷媒温度が上昇して温度式膨張弁が開かれ、必要に応じて直ちに冷却運転を再開することができ、しかも従来の冷凍システムのように冷媒復管における蒸発圧力調整弁を強制的に開くことにより生じる冷却運転の乱れも生じるおそれがなく、安定した冷却運転を行うことができる。
【図面の簡単な説明】
【図１】本発明に係る冷凍システムの実施例を示す構成図。
【図２】室温変化とバイパス開閉弁の開閉制御の関係を示すグラフ。
【符号の説明】
１圧縮機２冷媒往管
３油分離器４凝縮器
５温度式膨張弁６試験室
７空調器８乾式蒸発器
９冷媒復管１０蒸発圧力調整弁
１１ヒータ１２送風機
１３バイパス管１４バイパス開閉弁
１５制御回路１６温度センサ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dry cooling type refrigeration system suitable for air conditioning in an environmental test apparatus or the like.
[0002]
[Prior art and its problems]
The refrigeration system of the environmental test equipment that performs various tests by changing the temperature in the environmental test chamber has a dry cooling system, and the refrigeration system and the heater cool or heat the test chamber to the required temperature. It has become.
[0003]
In such an environmental test apparatus, when the room temperature in the test chamber is changed from a low temperature to a high temperature, the evaporation pressure adjustment valve provided on the suction side of the compressor in the refrigeration system is closed to increase the evaporation pressure in the evaporator. Thus, the cooling is stopped by the evaporator.
At this time, since the evaporation pressure adjusting valve is closed, the refrigerant does not flow into the refrigerant pipe, and therefore the pressure rises while the temperature of the refrigerant at the outlet side of the evaporator remains low.
[0004]
By the way, as the expansion valve on the evaporator inlet side of the refrigeration system, a temperature type expansion valve having a temperature sensing part for detecting the temperature and pressure of the refrigerant on the evaporator outlet side is generally used.
[0005]
The expansion valve detects that the refrigerant temperature on the outlet side of the evaporator is low and the pressure is high, and determines that the refrigerant is overcooled and closes. Furthermore, since the refrigerant does not flow when the expansion valve is closed while the room temperature is raised, the temperature of the refrigerant at the outlet side of the evaporator does not rise, and the expansion valve is not opened while it is determined that it is overcooled. Even if the rise is completed, it cannot be cooled, that is, the temperature of the test chamber cannot be lowered.
[0006]
Conventionally, when raising the room temperature, when the room temperature reaches the set temperature, the evaporation pressure adjusting valve is forcibly opened, the expansion valve is opened by lowering the evaporation pressure, and the refrigerant is circulated in the refrigerant pipe. By changing the temperature of the temperature sensing part, the evaporation pressure adjusting valve is controlled again.
[0007]
However, the evaporation pressure regulating valve is forcibly opened, so that the evaporation pressure of the refrigerant in the evaporator cannot be temporarily controlled, so that the temperature control in the test chamber is disturbed.
[0008]
【the purpose】
An object of the present invention is to provide a refrigeration system that can stably and smoothly restart the cooling operation after the cooling operation is stopped.
[0009]
[Configuration of the present invention]
In order to achieve the above object, in the refrigeration system according to claim 1 of the present invention, a condenser and a temperature type expansion valve are provided in the refrigerant outlet pipe from the discharge port of the compressor to the inlet of the dry evaporator in the air-conditioned room. In a refrigeration system provided with an evaporation pressure adjusting valve in a refrigerant return pipe extending from the outlet of the dry evaporator to the suction port of the compressor, one end is connected between the condenser and the expansion valve of the refrigerant outlet pipe The other end of the bypass pipe is connected between the expansion valve of the refrigerant outlet pipe and the evaporator, and when the temperature of the air-conditioned room is raised using a heater in the middle of the bypass pipe, When it reaches, the bypass on-off valve that is opened for a predetermined time is provided.
[0010]
In the refrigeration system according to claim 2 of the present invention, a condenser and a temperature type expansion valve are provided in a refrigerant outlet pipe extending from the discharge port of the compressor to the inlet of the dry evaporator in the air-conditioned room, and the dry evaporation In the refrigeration system having an evaporating pressure adjusting valve in the refrigerant return pipe from the outlet of the condenser to the suction port of the compressor, the other end of the bypass pipe having one end connected between the condenser and the expansion valve of the refrigerant outgoing pipe Is connected between the expansion valve of the refrigerant forward pipe and the evaporator, and a bypass on-off valve that is controlled to open and close based on a signal from the control circuit is provided in the middle of the bypass pipe. A temperature circuit for comparing a room temperature detected by a temperature sensor provided in the air-conditioned room with a preset temperature and raising the temperature of the air-conditioned room using a heater. When the room temperature reaches the set temperature, the temperature comparison circuit The timer circuit tighten become ON to open the bypass closing valve is as timer circuit after a predetermined time is configured to bypass shutoff valve is closed when turned OFF.
[0011]
【Example】
Embodiments of the refrigeration system according to the present invention will be described below in detail with reference to specific examples shown in the accompanying drawings.
The other end of the refrigerant forward pipe 2, one end of which is connected to the discharge port of the compressor 1, passes through an oil separator 3, a condenser 4, and an expansion valve 5 in an air conditioner 7 provided in a test chamber 6 that is an air-conditioned room. The dry evaporator 8 is connected.
[0012]
The other end of the refrigerant return pipe 9 having one end connected to the dry evaporator 8 is connected to the suction port of the compressor 1 through an evaporation pressure adjusting valve 10.
[0013]
The expansion valve 5 is a temperature type expansion valve, and its temperature sensing part 5a is provided in the refrigerant return pipe 9 in the vicinity of the evaporator outlet, and is an end of a pressure equalizing pipe 5b for detecting the refrigerant pressure in the refrigerant return pipe 9. The part is also connected in the vicinity of the temperature sensing part of the refrigerant return pipe.
In addition, the code | symbol 11 in a figure has shown the heater of the air conditioner, and 12 has shown the air blower.
[0014]
Thus, in the middle of the refrigerant outgoing pipe 2, one end is connected between the condenser 4 and the expansion valve 5, and the other end is connected between the expansion valve 5 and the evaporator 8 and straddles the expansion valve 5. A bypass pipe 13 is provided, and a bypass opening / closing valve 14 is provided in the middle of the bypass pipe 13.
[0015]
The bypass opening / closing valve 14 is opened for a predetermined time by a command from the control circuit 15 only when the temperature in the test chamber 6 (room temperature) reaches a preset temperature (set temperature) when raising the room temperature. It is closed during the cooling operation or when the cooling operation is stopped.
[0016]
The control circuit 15 includes a temperature comparison circuit and a timer. The temperature comparison circuit compares the room temperature detected by the temperature sensor 16 provided in the test chamber 6 with the set temperature, and when the room temperature is raised , When the set temperatures are equal, the timer is turned on by a signal from the temperature comparison circuit, the control circuit 15 opens the bypass opening / closing valve 14, and when the timer is turned off after a predetermined time, the control circuit 15 closes the bypass opening / closing valve 14.
Note that the time during which the timer is ON, that is, the time during which the bypass opening / closing valve 14 is opened varies depending on various factors such as the capacity of the evaporator 8 and the room temperature in the test chamber 6.
[0017]
Next, the operation of the refrigeration system according to the present invention configured as described above will be described.
During the cooling operation, the bypass on-off valve 14 is closed, and the refrigerant from the compressor 1 flows into the evaporator 8 through the oil separator 3, the condenser 4 and the expansion valve 5 through the refrigerant forward pipe 2, and the blower 12 is used to exchange heat with room air flowing through the air conditioner 7. Then, the refrigerant from the evaporator 8 is returned to the compressor through the evaporation pressure adjusting valve 10 by the refrigerant forward pipe 9.
[0018]
When raising the room temperature, the heater 11 heats the room air flowing through the air conditioner 7, and in the refrigeration system, the evaporation pressure adjusting valve 10 is closed to raise the evaporation pressure of the refrigerant in the evaporator 8. To stop the cooling in the evaporator.
At this time, the expansion valve 5 is closed by detecting that the refrigerant temperature at the outlet side of the evaporator 8 is low and high by the temperature sensing part 5a and the pressure equalizing pipe 5b.
[0019]
Thereafter, the temperature in the test chamber 6 detected by the temperature sensor 16 reaches the set temperature T _H which is preset as shown in FIG. 2, the control circuit as ON temperature comparator is a timer control circuit 15 When the bypass opening / closing valve 14 is opened and the timer is turned off after a predetermined time t has elapsed, the control circuit closes the bypass opening / closing valve 14.
[0020]
At this time, the refrigerant in the refrigerant forward pipe 2 flows through the bypass pipe 13 and flows into the evaporator 8, the refrigerant temperature in the refrigerant return pipe 9 in the evaporator and on the outlet side rises, and the expansion valve 5 Opened and ready to resume cooling operation.
This state is maintained as it is even when the room temperature is kept at a high temperature, and the cooling operation is performed immediately upon receiving a cooling operation command from the outside.
[0021]
【The invention's effect】
Since the refrigeration system according to the present invention includes a bypass pipe that straddles the expansion valve in the middle of the refrigerant outgoing pipe, the temperature in the air-conditioned room remains at the set temperature even if the cooling operation is stopped and the temperature expansion valve is closed. Since the refrigerant flows through the bypass pipe to the evaporator, the temperature of the refrigerant at the outlet of the evaporator rises, the temperature expansion valve is opened, and the cooling operation can be resumed immediately if necessary. There is no risk of disturbance of the cooling operation caused by forcibly opening the evaporation pressure adjusting valve in the refrigerant return pipe as in the refrigeration system, and a stable cooling operation can be performed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of a refrigeration system according to the present invention.
FIG. 2 is a graph showing a relationship between a change in room temperature and opening / closing control of a bypass opening / closing valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Compressor 2 Refrigerant outbound pipe 3 Oil separator 4 Condenser 5 Temperature expansion valve 6 Test chamber 7 Air conditioner 8 Dry evaporator 9 Refrigerant return pipe 10 Evaporation pressure adjustment valve 11 Heater 12 Blower 13 Bypass pipe 14 Bypass opening / closing valve 15 Control circuit 16 Temperature sensor

Claims

A refrigerant and a temperature type expansion valve are provided in the refrigerant forward pipe from the discharge port of the compressor to the inlet of the dry evaporator in the air-conditioned room, and the refrigerant reaches from the outlet of the dry evaporator to the inlet of the compressor In the refrigeration system having an evaporation pressure adjusting valve in the return pipe, the other end of the bypass pipe having one end connected between the condenser and the expansion valve of the refrigerant forward pipe is connected between the expansion valve and the evaporator of the refrigerant forward pipe. A refrigeration system comprising a bypass opening / closing valve that is connected and is opened for a predetermined time when the temperature of the air-conditioned room reaches a set temperature when the temperature of the air-conditioned room is increased using a heater in the middle of the bypass pipe.

A refrigerant and a temperature type expansion valve are provided in the refrigerant forward pipe from the discharge port of the compressor to the inlet of the dry evaporator in the air-conditioned room, and the refrigerant reaches from the outlet of the dry evaporator to the inlet of the compressor In the refrigeration system having an evaporation pressure adjusting valve in the return pipe, the other end of the bypass pipe having one end connected between the condenser and the expansion valve of the refrigerant forward pipe is connected between the expansion valve and the evaporator of the refrigerant forward pipe. A bypass on-off valve connected and controlled to open and close based on a signal from the control circuit is provided in the middle of the bypass pipe, the control circuit includes a temperature comparison circuit and a timer circuit, and the temperature comparison circuit is in the air-conditioned room When the room temperature reaches the set temperature when the temperature inside the air-conditioned room is raised using a heater, the temperature comparison circuit detects the temperature of the timer circuit. If you turn ON the bypass Open closed refrigeration system comprising a configuration in which the timer circuit is turned OFF after a predetermined time the bypass opening and closing valve is closed.