JP2007093017A - Refrigerating apparatus - Google Patents

Refrigerating apparatus Download PDF

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JP2007093017A
JP2007093017A JP2005254657A JP2005254657A JP2007093017A JP 2007093017 A JP2007093017 A JP 2007093017A JP 2005254657 A JP2005254657 A JP 2005254657A JP 2005254657 A JP2005254657 A JP 2005254657A JP 2007093017 A JP2007093017 A JP 2007093017A
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refrigeration
oil
stage compressor
compressor
low
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JP3861913B1 (en
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Satoru Sakae
覚 阪江
Takemune Mesaki
丈統 目▲崎▼
Masaaki Takegami
雅章 竹上
Kazuhide Nomura
和秀 野村
Azuma Kondo
東 近藤
Yoshinari Oda
吉成 小田
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Daikin Ind Ltd
ダイキン工業株式会社
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<P>PROBLEM TO BE SOLVED: To prevent failure by lubricating each of compressors 11, 12, 55 with minimum refrigerator oil, in a refrigerating apparatus comprising a refrigerant circuit 6 where a low-stage compressor 55 and a high-speed compressors 11, 12 are connected in series to perform two-stage refrigerating cycle. <P>SOLUTION: A pressure regulating valve 71 for reducing a pressure on a suction side of the high-stage compressors 11, 12 less than a pressure in the dome of the low-stage compressor 55 is connected to a delivery side of the low-stage compressor 55, one end of an oil return passage 72 is connected to the dome of the low-stage compressor 55, and the other end is connected to the suction side of the high-stage compressors 11, 12 by bypassing the pressure regulating valve 71. Thus, the refrigerator oil stored in the dome of the low-stage compressor 55 can be returned to the high-stage compressors 11, 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、低段圧縮機と高段圧縮機とが直列に接続されて二段圧縮冷凍サイクルを行う冷媒回路を備えた冷凍装置に関し、特にその冷凍機油を圧縮機に戻す機構に関するものである。   The present invention relates to a refrigeration apparatus having a refrigerant circuit in which a low-stage compressor and a high-stage compressor are connected in series to perform a two-stage compression refrigeration cycle, and more particularly to a mechanism for returning the refrigeration oil to the compressor. .
従来より、冷凍装置としては冷媒回路で冷媒を循環させて蒸気圧縮式冷凍サイクルを行うものが一般的である。また、従来より、この種の冷凍装置として、冷媒の圧縮を二段に分けて行う二段圧縮冷凍サイクルを行うものが知られている。   Conventionally, a refrigeration apparatus generally performs a vapor compression refrigeration cycle by circulating a refrigerant in a refrigerant circuit. Conventionally, as this type of refrigeration apparatus, one that performs a two-stage compression refrigeration cycle in which refrigerant is compressed in two stages is known.
上記二段圧縮式の冷凍装置には、低段側の圧縮機と高段側の圧縮機とが設けられている。蒸発器からの低圧のガス冷媒は、低段圧縮機に吸入されて中間圧まで圧縮される。低段圧縮機の吐出冷媒は、高段圧縮機へ送られて更に圧縮される。そして、高段圧縮機の吐出冷媒を凝縮器へ送って冷凍サイクルを行う。   The two-stage compression refrigeration apparatus is provided with a low-stage compressor and a high-stage compressor. The low-pressure gas refrigerant from the evaporator is sucked into the low-stage compressor and compressed to an intermediate pressure. The refrigerant discharged from the low stage compressor is sent to the high stage compressor and further compressed. Then, the refrigerant discharged from the high stage compressor is sent to the condenser to perform a refrigeration cycle.
そのような冷凍装置に用いられる冷媒は、圧縮機を潤滑するための冷凍機油を熔解し易いので、凝縮器における凝縮液には、圧縮機の吐出ガス中に含まれている冷凍機油が熔解している。この冷媒液が蒸発器に流れ、冷媒が蒸発すると油が分離されるが、この油が圧縮機に戻り易いような配管上の工夫を加えないと、冷媒回路の低圧部に貯まったままになり、圧縮機内が十分に潤滑されず、焼損することになる。   Since the refrigerant used in such a refrigeration apparatus is easy to melt the refrigeration oil for lubricating the compressor, the condensate in the condenser dissolves the refrigeration oil contained in the compressor discharge gas. ing. When this refrigerant liquid flows into the evaporator and the refrigerant evaporates, the oil is separated. However, unless the piping is devised so that this oil easily returns to the compressor, it will remain in the low-pressure part of the refrigerant circuit. The inside of the compressor is not sufficiently lubricated and burns out.
そこで、例えば、特許文献1では、高段圧縮機から吐出された冷媒中の冷凍機油を分離する油分離器を設け、この油分離器から高段圧縮機及び低段圧縮機にそれぞれ冷凍機油を返す返油通路を設けるものが開示されている。   Therefore, for example, in Patent Document 1, an oil separator that separates refrigeration oil in the refrigerant discharged from the high-stage compressor is provided, and refrigeration oil is supplied from the oil separator to the high-stage compressor and the low-stage compressor, respectively. An apparatus for providing a return oil return passage is disclosed.
一方、例えば、特許文献2では、低段圧縮機から吐出された冷媒中の冷凍機油を分離する気液分離器を設け、この気液分離器から低段圧縮機に冷凍機油を戻す返油通路を設けるものが示されている。
特開平7−260263号公報 国際公開第02/46663号パンフレット
On the other hand, for example, in Patent Document 2, a gas-liquid separator that separates refrigeration oil in refrigerant discharged from a low-stage compressor is provided, and an oil return passage that returns the refrigeration oil from the gas-liquid separator to the low-stage compressor. What is provided is shown.
JP-A-7-260263 International Publication No. 02/46663 Pamphlet
しかしながら、特許文献1及び2の冷凍装置では、いずれも低段圧縮機内に貯まった冷凍機油を高段圧縮機に戻すことができないので、高段圧縮機内の冷凍機油の欠乏による高段圧縮機の焼損を防ぐために、新たに冷凍機油を充填する必要がある。したがって、冷凍機油を充填する手間がかかるとともに、コスト面でも不利である。   However, in both of the refrigeration apparatuses of Patent Documents 1 and 2, since the refrigeration oil stored in the low stage compressor cannot be returned to the high stage compressor, the high stage compressor due to the lack of the refrigeration oil in the high stage compressor. In order to prevent burning, it is necessary to refill the refrigerating machine oil. Therefore, it takes time and effort to fill the refrigerating machine oil and is disadvantageous in terms of cost.
本発明は、かかる点に鑑みてなされたものであり、その目的とするところは、簡単な構成で、冷凍機油が低段圧縮機及び高段圧縮機側に適切に行き渡るようにすることにより、最少の冷凍機油で各圧縮機を潤滑して故障が発生しないようにすることにある。   The present invention has been made in view of the above points, and the object of the present invention is to make the refrigeration oil properly spread to the low-stage compressor and the high-stage compressor with a simple configuration. The aim is to lubricate each compressor with the least amount of refrigeration oil so that no failure occurs.
上記の目的を達成するために、この発明では、冷凍機油を低段圧縮機(55)から高段圧縮機(11,12)側に戻すようにした。   In order to achieve the above object, in the present invention, the refrigeration oil is returned from the low stage compressor (55) to the high stage compressor (11, 12) side.
具体的には、第1の発明では、低段圧縮機(55)と高段圧縮機(11,12)とが直列に接続されて二段圧縮冷凍サイクルを行う冷媒回路(6)を備えた冷凍装置(1)を対象とする。   Specifically, in the first invention, a low-stage compressor (55) and a high-stage compressor (11, 12) are connected in series to provide a refrigerant circuit (6) that performs a two-stage compression refrigeration cycle. For refrigeration equipment (1).
そして、冷凍機油を上記低段圧縮機(55)から上記高段圧縮機(11,12)に戻す返油手段(70)を備える構成とする。   And it is set as the structure provided with the oil return means (70) which returns refrigeration oil to the said high stage compressor (11,12) from the said low stage compressor (55).
すなわち、二段圧縮冷凍サイクルを行う冷媒回路(6)を備えた冷凍装置(1)では、圧縮機(11,22,55)内を潤滑する冷凍機油は、圧力の低い低段圧縮機(55)側に貯まる傾向にあるが、上記の構成によると低段圧縮機(55)に貯まる冷凍機油が返油手段(70)により低段圧縮機(55)から高段圧縮機(11,12)に戻される。   That is, in the refrigeration apparatus (1) having the refrigerant circuit (6) that performs the two-stage compression refrigeration cycle, the refrigeration oil that lubricates the compressor (11, 22, 55) is a low-pressure compressor (55 However, according to the above configuration, the refrigerating machine oil stored in the low-stage compressor (55) is returned from the low-stage compressor (55) to the high-stage compressor (11, 12) by the oil return means (70). Returned to
第2の発明では、上記第1の発明において、上記低段圧縮機(55)は、その高圧部に冷凍機油が貯まるように構成される一方、上記返油手段(70)は、低段圧縮機(55)の高圧部に貯まった冷凍機油を上記高段圧縮機(11,12)に戻す構成とする。   According to a second aspect, in the first aspect, the low-stage compressor (55) is configured such that refrigeration oil is stored in a high-pressure portion thereof, while the oil return means (70) is a low-stage compressor. The refrigeration oil stored in the high pressure section of the machine (55) is returned to the high stage compressor (11, 12).
上記の構成によると、冷凍機油は、返油手段(70)により、冷凍機油が貯まる低段圧縮機(55)の高圧部から高段圧縮機(11,12)に戻される。   According to the above configuration, the refrigerating machine oil is returned to the high stage compressor (11, 12) from the high pressure portion of the low stage compressor (55) where the refrigerating machine oil is stored by the oil return means (70).
第3の発明では、上記第2の発明において、上記返油手段(70)は、上記低段圧縮機(55)の吐出側に設けられ、高段圧縮機(11,12)の吸入側を低段圧縮機(55)の高圧部よりも低圧にするための減圧手段(71)と、一端が低段圧縮機(55)の高圧部に接続されると共に、他端が減圧手段(71)をバイパスして高段圧縮機(11,12)の吸入側に接続される返油通路(72)とを備える構成とする。   According to a third aspect, in the second aspect, the oil return means (70) is provided on the discharge side of the low stage compressor (55), and the suction side of the high stage compressor (11, 12) is Pressure reducing means (71) for lowering the pressure than the high pressure part of the low stage compressor (55), one end connected to the high pressure part of the low stage compressor (55), and the other end of the pressure reducing means (71) And an oil return passage (72) connected to the suction side of the high stage compressor (11, 12).
上記の構成によると、減圧手段(71)により、高段圧縮機(11,12)の吸入側は低段圧縮機(55)の高圧部よりも低圧になるので、低段圧縮機(55)の高圧部に貯まった冷凍機油は、減圧手段(71)をバイパスして返油通路(72)を通って高段圧縮機(11,12)の吸入側に押し出される。   According to the above configuration, the suction side of the high stage compressor (11, 12) is lower in pressure than the high pressure part of the low stage compressor (55) by the decompression means (71), so the low stage compressor (55) The refrigerating machine oil stored in the high-pressure part of the engine bypasses the decompression means (71), passes through the oil return passage (72), and is pushed out to the suction side of the high-stage compressor (11, 12).
第4の発明では、上記第1の発明において、上記低段圧縮機(55)は、高圧空間となるドーム内に冷凍機油が貯まるように構成される一方、上記返油手段(70)は、低段圧縮機(55)のドーム内に貯まった冷凍機油を上記高段圧縮機(11,12)に戻す構成とする。   According to a fourth aspect, in the first aspect, the low-stage compressor (55) is configured such that refrigeration oil is stored in a dome serving as a high-pressure space, while the oil return means (70) The refrigeration oil stored in the dome of the low stage compressor (55) is returned to the high stage compressor (11, 12).
上記の構成によると、冷凍機油は、返油手段(70)により、冷凍機油が貯まる低段圧縮機(55)のドーム内から高段圧縮機(11,12)に戻される。   According to the above configuration, the refrigerating machine oil is returned to the high stage compressor (11, 12) from the dome of the low stage compressor (55) in which the refrigerating machine oil is stored by the oil return means (70).
第5の発明では、上記第4の発明において、上記返油手段(70)は、上記低段圧縮機(55)の吐出側に設けられ、高段圧縮機(11,12)の吸入側を低段圧縮機(55)のドーム内よりも低圧にするための減圧手段(71)と、一端が低段圧縮機(55)のドームに接続されると共に、他端が減圧手段(71)をバイパスして高段圧縮機(11,12)の吸入側に接続される返油通路(72)とを備える構成とする。   According to a fifth aspect, in the fourth aspect, the oil return means (70) is provided on the discharge side of the low stage compressor (55), and the suction side of the high stage compressor (11, 12) is The decompression means (71) for lowering the pressure in the dome of the low stage compressor (55), and one end of the decompression means (71) are connected to the dome of the low stage compressor (55). An oil return passage (72) connected to the suction side of the high-stage compressor (11, 12) by bypass is provided.
上記の構成によると、減圧手段(71)により、高段圧縮機(11,12)の吸入側は低段圧縮機(55)のドーム内よりも低圧になるので、低段圧縮機(55)のドーム内に貯まった冷凍機油は、減圧手段(71)をバイパスして返油通路(72)を通って高段圧縮機(11,12)の吸入側に押し出される。   According to the above configuration, the decompression means (71) causes the suction side of the high stage compressor (11, 12) to be at a lower pressure than in the dome of the low stage compressor (55), so the low stage compressor (55) The refrigerating machine oil stored in the dome is pushed out to the suction side of the high stage compressor (11, 12) through the oil return passage (72), bypassing the decompression means (71).
第6の発明では、上記第2,第3,第4又は第5の発明において、上記低段圧縮機(55a,55b,55c)が複数設けられ、該複数の低段圧縮機(55a,55b,55c)が互いに並列に接続されており、上記返油手段(70)は、上記複数の低段圧縮機(55a,55b,55c)のうちの1台である返油対象の低段圧縮機(55a)から上記高段圧縮機(11,12)へ冷凍機油を戻すように構成される一方、上記返油対象の低段圧縮機(55a)以外の低段圧縮機(55b,55c)から該返油対象の低段圧縮機(55a)へ冷凍機油を送るための送油通路(67a,67b)を備える構成とする。   According to a sixth invention, in the second, third, fourth or fifth invention, a plurality of the low stage compressors (55a, 55b, 55c) are provided, and the plurality of low stage compressors (55a, 55b) are provided. , 55c) are connected in parallel to each other, and the oil return means (70) is one of the plurality of low stage compressors (55a, 55b, 55c) and is a low stage compressor to be returned. (55a) from the low-stage compressor (55b, 55c) other than the low-stage compressor (55a) to be returned, while being configured to return the refrigeration oil to the high-stage compressor (11, 12). An oil feed passage (67a, 67b) for sending refrigeration oil to the low-stage compressor (55a) to be returned is provided.
上記の構成によると、返油対象の低段圧縮機(55a)以外の低段圧縮機(55b,55c)に溜まった冷凍機油は、送油通路(67a,67b)を通って返油対象の低段圧縮機(55a)へ送られる。そして、高段圧縮機(11,12)へは、返油対象の低段圧縮機(55a)だけから冷凍機油が送り返される。つまり、この第6の発明では、返油対象の低段圧縮機(55a)に冷凍機油が集められ、返油対象の低段圧縮機(55a)に集められた冷凍機油が高段圧縮機(11,12)へ送られる。   According to the above configuration, the refrigeration oil accumulated in the low-stage compressors (55b, 55c) other than the low-stage compressor (55a) subject to oil return passes through the oil feed passage (67a, 67b). It is sent to the low stage compressor (55a). Then, the refrigeration oil is sent back to the high stage compressor (11, 12) only from the low stage compressor (55a) to be returned. In other words, in the sixth aspect of the invention, the refrigeration oil is collected in the low stage compressor (55a) to be returned, and the refrigeration oil collected in the low stage compressor (55a) to be returned is the high stage compressor (55a). 11,12).
第7の発明では、上記第1の発明において、上記低段圧縮機(55)の吐出側には、低段圧縮機(55)から吐出された冷凍機油を捕集する油分離器(64)が設けられる一方、上記高段圧縮機(11,12)の吸入側を上記油分離器(64)内よりも低圧にするために油分離器(64)よりも高段圧縮機(11,12)側に設けられる減圧手段(71)と、一端が油分離器(64)に接続されると共に、他端が減圧手段(71)をバイパスして高段圧縮機(11,12)の吸入側に接続される返油通路(72)とを備える構成とする。   According to a seventh aspect, in the first aspect, an oil separator (64) that collects refrigeration oil discharged from the low-stage compressor (55) is provided on a discharge side of the low-stage compressor (55). On the other hand, in order to make the suction side of the high-stage compressor (11, 12) at a lower pressure than in the oil separator (64), the high-stage compressor (11, 12) than the oil separator (64) ) Side pressure reducing means (71) and one end connected to the oil separator (64) and the other end bypassing the pressure reducing means (71) and the suction side of the high-stage compressor (11, 12) And an oil return passage (72) connected to.
上記の構成によると、減圧手段(71)により、高段圧縮機(11,12)の吸入側は油分離器(64)内よりも低圧になるので、油分離器(64)が捕集した冷凍機油は、減圧手段(71)をバイパスして返油通路(72)を通って高段圧縮機(11,12)の吸入側に押し出される。これにより、冷凍機油が低段圧縮機(55)から高段圧縮機(11,12)へ戻される。   According to the above configuration, since the suction side of the high-stage compressor (11, 12) has a lower pressure than the inside of the oil separator (64) by the pressure reducing means (71), the oil separator (64) is collected. The refrigerating machine oil is pushed out to the suction side of the high stage compressor (11, 12) through the oil return passage (72), bypassing the decompression means (71). As a result, the refrigeration oil is returned from the low stage compressor (55) to the high stage compressor (11, 12).
以上説明したように、本発明によれば、二段圧縮冷凍サイクルを行う冷媒回路(6)を備えた冷凍装置(1)において、返油手段(70)により、圧力の低い低段圧縮機(55)側に貯まる傾向にある冷凍機油を低段圧縮機(55)から高段圧縮機(11,12)に戻すようにしている。このため、高段圧縮機(11,12)内の冷凍機油が欠乏することはないので、新たに冷凍機油を充填する必要がない。よって、冷凍機油を充填する手間がかからない。また、低段圧縮機(55)に冷凍機油が貯まっていくことを防止することができるので、低段圧縮機(55)内で冷凍機油による回転抵抗が減り、運転効率が良くなる。   As described above, according to the present invention, in the refrigeration apparatus (1) including the refrigerant circuit (6) for performing the two-stage compression refrigeration cycle, the low pressure compressor (70) having a low pressure is provided by the oil return means (70). Refrigerating machine oil that tends to accumulate on the 55) side is returned from the low-stage compressor (55) to the high-stage compressor (11, 12). For this reason, since the refrigerating machine oil in the high stage compressors (11, 12) is not deficient, it is not necessary to newly fill the refrigerating machine oil. Therefore, it does not take time to fill the refrigerating machine oil. In addition, since the refrigerating machine oil can be prevented from being stored in the low stage compressor (55), the rotational resistance due to the refrigerating machine oil is reduced in the low stage compressor (55), and the operation efficiency is improved.
上記第3の発明によれば、低段圧縮機(55)の吐出側に減圧手段(71)を設け、高段圧縮機(11,12)の吸入側を低段圧縮機(55)の高圧部よりも低圧にするとともに、返油通路(72)の一端を低段圧縮機(55)の高圧部に接続し、他端を減圧手段(71)をバイパスして高段圧縮機(11,12)の吸入側に接続することにより、低段圧縮機(55)の高圧部に貯まった冷凍機油を高段圧縮機(11,12)に戻すようにしている。このため、簡単な構成により、冷凍機油を充填する手間がかからず、最少の冷凍機油で効率よく運転が行われる冷凍装置(1)が得られる。   According to the third aspect, the pressure reducing means (71) is provided on the discharge side of the low stage compressor (55), and the suction side of the high stage compressor (11, 12) is connected to the high pressure of the low stage compressor (55). The lower end of the oil return passage (72) is connected to the high pressure section of the low stage compressor (55), and the other end is bypassed the decompression means (71). By connecting to the suction side of 12), the refrigeration oil stored in the high pressure part of the low stage compressor (55) is returned to the high stage compressor (11, 12). Therefore, with a simple configuration, it is possible to obtain a refrigeration apparatus (1) that does not require the effort of filling the refrigerating machine oil and can be efficiently operated with the minimum refrigerating machine oil.
上記第5の発明によれば、低段圧縮機(55)の吐出側に減圧手段(71)を設け、高段圧縮機(11,12)の吸入側を低段圧縮機(55)のドーム内よりも低圧にするとともに、返油通路(72)の一端を低段圧縮機(55)のドームに接続し、他端を減圧手段(71)をバイパスして高段圧縮機(11,12)の吸入側に接続することにより、低段圧縮機(55)のドーム内に貯まった冷凍機油を高段圧縮機(11,12)に戻すようにしている。このため、簡単な構成により、冷凍機油を充填する手間がかからず、最少の冷凍機油で効率よく運転が行われる冷凍装置(1)が得られる。   According to the fifth aspect of the present invention, the pressure reducing means (71) is provided on the discharge side of the low stage compressor (55), and the suction side of the high stage compressor (11, 12) is connected to the dome of the low stage compressor (55). The oil return passage (72) has one end connected to the dome of the low-stage compressor (55) and the other end bypassed the decompression means (71). ), The refrigerating machine oil stored in the dome of the low-stage compressor (55) is returned to the high-stage compressor (11, 12). Therefore, with a simple configuration, it is possible to obtain a refrigeration apparatus (1) that does not require the effort of filling the refrigerating machine oil and can be efficiently operated with the minimum refrigerating machine oil.
上記第6の発明によれば、複数台の低段圧縮機(55a,55b,55c)が設けられている場合であっても、返油手段(70)は、そのうちの1台である返油対象の低段圧縮機(55a)だけから冷凍機油を高段圧縮機(11,12)へ戻せばよいことになる。従って、この発明によれば、それぞれの低段圧縮機(55a,55b,55c)から個別に冷凍機油を高段圧縮機(11,12)へ戻す必要が無くなり、返油手段(70)の構成を簡素化することができる。   According to the sixth aspect, even when a plurality of low-stage compressors (55a, 55b, 55c) are provided, the oil return means (70) is one of them. It is only necessary to return the refrigeration oil to the high-stage compressor (11, 12) only from the target low-stage compressor (55a). Therefore, according to the present invention, it is not necessary to individually return the refrigeration oil to the high-stage compressor (11, 12) from each low-stage compressor (55a, 55b, 55c), and the configuration of the oil return means (70) Can be simplified.
上記第7の発明によれば、低段圧縮機(55)の吐出側に設けられた油分離器(64)よりも高段圧縮機(11,12)側に減圧手段(71)を設け、高段圧縮機(11,12)の吸入側を油分離器(64)内よりも低圧にするとともに、返油通路(72)の一端を油分離器(64)に接続し、他端を減圧手段(71)をバイパスして高段圧縮機(11,12)の吸入側に接続することにより、油分離器(64)が捕集した冷凍機油を高段圧縮機(11,12)に戻すようにしている。このため、簡単な構成により、冷凍機油を充填する手間がかからず、最少の冷凍機油で効率よく運転が行われる冷凍装置(1)が得られる。   According to the seventh aspect of the present invention, the pressure reducing means (71) is provided on the high stage compressor (11, 12) side than the oil separator (64) provided on the discharge side of the low stage compressor (55), The suction side of the high stage compressor (11, 12) is set to a lower pressure than in the oil separator (64), one end of the oil return passage (72) is connected to the oil separator (64), and the other end is decompressed. By bypassing the means (71) and connecting to the suction side of the high stage compressor (11, 12), the refrigeration oil collected by the oil separator (64) is returned to the high stage compressor (11, 12). I am doing so. Therefore, with a simple configuration, it is possible to obtain a refrigeration apparatus (1) that does not require the effort of filling the refrigerating machine oil and can be efficiently operated with the minimum refrigerating machine oil.
以下、本発明の実施形態を図面に基づいて説明する。なお、以下の実施形態は、本質的に好ましい例示であって、本発明、その適用物や用途の範囲を制限することを意図するものではない。   Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the following embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or a use.
−冷凍装置の構成−
図1に示すように、実施形態にかかる冷凍装置(1)は、室内の空調と飲食物の冷蔵及び冷凍を行う冷凍装置であって、例えば、コンビニエンスストアに設置されている。冷凍装置(1)は、室外ユニット(2)と、室内ユニット(3)と、冷蔵ユニット(4)と、冷凍ユニット(5)とが接続されてなる冷媒回路(6)を備えている。
-Configuration of refrigeration equipment-
As shown in FIG. 1, the refrigeration apparatus (1) according to the embodiment is a refrigeration apparatus that performs indoor air conditioning and refrigeration and freezing of food and drink, and is installed, for example, in a convenience store. The refrigeration apparatus (1) includes a refrigerant circuit (6) in which an outdoor unit (2), an indoor unit (3), a refrigeration unit (4), and a refrigeration unit (5) are connected.
室外ユニット(2)には、互いに並列に接続された高段圧縮機としての第1及び第2圧縮機(11,12)と、室外熱交換器(13)と、レシーバ(14)とが設けられている。第1圧縮機(11)は容量可変型の圧縮機であり、インバータ圧縮機によって構成されている。第2圧縮機(12)は、容量固定型の圧縮機であり、非インバータ圧縮機によって構成されている。圧縮機(11,12)の吐出側には、四路切換弁(15)が設けられている。圧縮機(11,12)の吐出配管は、四路切換弁(15)の第1ポートに接続されている。圧縮機(11,12)と四路切換弁(15)との間には、油分離器(16)と温度センサ(81)と圧力センサ(82)とが設けられている。第1圧縮機(11)の吐出配管には、高圧圧力スイッチ(40)が設けられている。圧縮機(11,12)の吸入配管(17)には、圧力センサ(83)が設けられている。油戻し管(18)は油分離器(16)と吸入配管(17)とを接続している。油戻し管(18)には、電磁弁(19)が設けられている。圧縮機(11,12)の均油管(20)の一端は、第2圧縮機(12)の側部に接続され、均油管(20)の他端は第1圧縮機(11)の吸入配管(22)に接続されている。均油管(20)には、電磁弁(21)が設けられている。   The outdoor unit (2) is provided with first and second compressors (11, 12) as high-stage compressors connected in parallel to each other, an outdoor heat exchanger (13), and a receiver (14). It has been. The first compressor (11) is a variable capacity compressor, and is composed of an inverter compressor. The second compressor (12) is a fixed capacity type compressor, and is constituted by a non-inverter compressor. A four-way switching valve (15) is provided on the discharge side of the compressor (11, 12). The discharge pipe of the compressor (11, 12) is connected to the first port of the four-way selector valve (15). An oil separator (16), a temperature sensor (81), and a pressure sensor (82) are provided between the compressors (11, 12) and the four-way selector valve (15). The discharge pipe of the first compressor (11) is provided with a high pressure switch (40). A pressure sensor (83) is provided in the suction pipe (17) of the compressor (11, 12). The oil return pipe (18) connects the oil separator (16) and the suction pipe (17). The oil return pipe (18) is provided with a solenoid valve (19). One end of the oil equalizing pipe (20) of the compressor (11, 12) is connected to the side of the second compressor (12), and the other end of the oil equalizing pipe (20) is the suction pipe of the first compressor (11). Connected to (22). The oil equalizing pipe (20) is provided with a solenoid valve (21).
四路切換弁(15)の第2ポートは、冷媒配管(30)を介して室外熱交換器(13)の一端に接続されている。室外熱交換器(13)の他端は、冷媒配管(24)を介してレシーバ(14)に接続されている。レシーバ(14)の液側配管(25)と冷媒配管(24)とは、バイパス管(26)を介して接続されている。バイパス管(26)には、電子膨張弁(27)が設けられている。   The second port of the four-way selector valve (15) is connected to one end of the outdoor heat exchanger (13) via the refrigerant pipe (30). The other end of the outdoor heat exchanger (13) is connected to the receiver (14) via the refrigerant pipe (24). The liquid side pipe (25) and the refrigerant pipe (24) of the receiver (14) are connected via a bypass pipe (26). The bypass pipe (26) is provided with an electronic expansion valve (27).
レシーバ(14)の液側配管(25)は冷媒配管(35)に接続され、この冷媒配管(35)は室外ユニット(2)の外部に延びている。冷媒配管(35)と冷媒配管(24)のレシーバ(14)寄りの部分とは、冷媒配管(41)を介して接続されている。冷媒配管(41)には、レシーバ(14)からの冷媒の流れを阻止する逆止弁(CV)が設けられている。なお、冷媒配管(24)にも、レシーバ(14)からの冷媒の流れを阻止する逆止弁(CV)が設けられている。   The liquid side pipe (25) of the receiver (14) is connected to the refrigerant pipe (35), and the refrigerant pipe (35) extends to the outside of the outdoor unit (2). The refrigerant pipe (35) and the portion of the refrigerant pipe (24) near the receiver (14) are connected via the refrigerant pipe (41). The refrigerant pipe (41) is provided with a check valve (CV) that blocks the flow of refrigerant from the receiver (14). The refrigerant pipe (24) is also provided with a check valve (CV) that blocks the flow of refrigerant from the receiver (14).
圧縮機(11,12)の吸入配管(17)は、四路切換弁(15)の第3ポートに接続している。吸入配管(17)には、温度センサ(37)が設けられている。吸入配管(17)における四路切換弁(15)と温度センサ(37)との間には、室外ユニット(2)の外部に延びる冷媒配管(38)が接続されている。   The suction pipe (17) of the compressor (11, 12) is connected to the third port of the four-way switching valve (15). The suction pipe (17) is provided with a temperature sensor (37). A refrigerant pipe (38) extending outside the outdoor unit (2) is connected between the four-way switching valve (15) and the temperature sensor (37) in the suction pipe (17).
四路切換弁(15)の第4ポートは、室外ユニット(2)の外部に延びる冷媒配管(39)に接続されている。なお、四路切換弁(15)は、下記の第1状態または第2状態に切り替え自在に設定されるものであり、第1状態は、第1ポートと第2ポートとを連通すると共に第3ポートと第4ポートとを連通する状態であり、第2状態は、第1ポートと第4ポートとを連通すると共に第2ポートと第3ポートとを連通する状態である。   The fourth port of the four-way selector valve (15) is connected to a refrigerant pipe (39) extending to the outside of the outdoor unit (2). The four-way switching valve (15) is set so as to be switchable to the following first state or second state. In the first state, the first port communicates with the second port and the third state The second state is a state in which the first port and the fourth port are communicated with each other, and the second port and the third port are in communication with each other.
上記室外ユニット(2)には、室外熱交換器(13)に空気を供給する室外ファン(23)と、室外空気温度を検出する温度センサ(50)とが設けられている。   The outdoor unit (2) is provided with an outdoor fan (23) for supplying air to the outdoor heat exchanger (13) and a temperature sensor (50) for detecting the outdoor air temperature.
室内ユニット(3)は、室内の空気調和を実行するものであり、室内熱交換器(42)と室内電子膨張弁(43)と室内ファン(44)とを備えている。室内熱交換器(42)の一端は、冷媒配管(39)に接続されている。室内熱交換器(42)の他端は、冷媒配管(35)に接続されている。室内電子膨張弁(43)は、冷媒配管(35)に設けられている。室内熱交換器(42)には温度センサ(45)が設けられ、冷媒配管(39)には温度センサ(46)が設けられている。なお、(51)は室内空気温度を検出する温度センサである。   The indoor unit (3) performs indoor air conditioning, and includes an indoor heat exchanger (42), an indoor electronic expansion valve (43), and an indoor fan (44). One end of the indoor heat exchanger (42) is connected to the refrigerant pipe (39). The other end of the indoor heat exchanger (42) is connected to the refrigerant pipe (35). The indoor electronic expansion valve (43) is provided in the refrigerant pipe (35). The indoor heat exchanger (42) is provided with a temperature sensor (45), and the refrigerant pipe (39) is provided with a temperature sensor (46). In addition, (51) is a temperature sensor which detects indoor air temperature.
冷蔵ユニット(4)は、飲食物を冷蔵するものであり、冷蔵用冷却器(47)と冷蔵用電子膨張弁(48)と冷蔵用ファン(49)とを備えている。冷蔵用冷却器(47)の一端は、冷媒配管(36)に接続されている。冷媒配管(36)は、上記冷媒配管(35)に合流している。冷蔵用冷却器(47)の他端は、冷媒配管(38)に接続されている。冷蔵用電子膨張弁(48)は、冷媒配管(36)に設けられている。冷蔵用冷却器(47)には温度センサ(53)が設けられ、冷媒配管(38)には温度センサ(54)が設けられている。また、冷蔵ユニット(4)には、庫内温度を検出する温度センサ(52)が設けられている。   The refrigeration unit (4) refrigerates food and drinks, and includes a refrigeration cooler (47), a refrigeration electronic expansion valve (48), and a refrigeration fan (49). One end of the refrigeration cooler (47) is connected to the refrigerant pipe (36). The refrigerant pipe (36) joins the refrigerant pipe (35). The other end of the refrigeration cooler (47) is connected to the refrigerant pipe (38). The refrigeration electronic expansion valve (48) is provided in the refrigerant pipe (36). The refrigeration cooler (47) is provided with a temperature sensor (53), and the refrigerant pipe (38) is provided with a temperature sensor (54). The refrigeration unit (4) is provided with a temperature sensor (52) that detects the internal temperature.
冷凍ユニット(5)は、飲食物を冷凍するものであり、低段圧縮機としての冷凍用圧縮機(55)と、冷凍用冷却器(56)と、冷凍用電子膨張弁(57)と、冷凍用ファン(58)とを備えている。冷凍ユニット(5)は、冷媒配管(36)から分岐している冷媒配管(59)と、冷媒配管(38)から分岐している冷媒配管(60)とに接続されている。冷凍用電子膨張弁(57)、冷凍用冷却器(56)及び冷凍用圧縮機(55)はこの順に接続されており、冷凍用電子膨張弁(57)は冷媒配管(59)に接続され、冷凍用圧縮機(55)の吐出側は冷媒配管(60)に接続されている。冷凍用冷却器(56)には温度センサ(61)が設けられ、冷凍用冷却器(56)の出口側配管(つまり、冷凍用冷却器(56)と冷凍用圧縮機(55)との間の配管)には、温度センサ(62)が設けられている。また、冷凍ユニット(5)には、庫内温度を検出する温度センサ(63)が設けられている。   The refrigeration unit (5) is for freezing food and drink, a refrigeration compressor (55) as a low-stage compressor, a refrigeration cooler (56), a freezing electronic expansion valve (57), And a refrigeration fan (58). The refrigeration unit (5) is connected to the refrigerant pipe (59) branched from the refrigerant pipe (36) and the refrigerant pipe (60) branched from the refrigerant pipe (38). The refrigeration electronic expansion valve (57), the refrigeration cooler (56), and the refrigeration compressor (55) are connected in this order, and the refrigeration electronic expansion valve (57) is connected to the refrigerant pipe (59), The discharge side of the refrigeration compressor (55) is connected to the refrigerant pipe (60). The refrigeration cooler (56) is provided with a temperature sensor (61), and the outlet side piping of the refrigeration cooler (56) (that is, between the refrigeration cooler (56) and the refrigeration compressor (55)). ) Is provided with a temperature sensor (62). The refrigeration unit (5) is provided with a temperature sensor (63) that detects the internal temperature.
冷凍用圧縮機(55)は、容量可変型の高圧ドーム型圧縮機であり、インバータ圧縮機により構成されている。冷凍用圧縮機(55)の吐出配管には、油分離器(64)が設けられている。油分離器(64)の油戻し管(65)は、冷凍用圧縮機(55)の吸入配管(68)に接続されている。油戻し管(65)には、減圧機構としてキャピラリーチューブ(69)が設けられている。吸入配管(68)から冷凍用圧縮機(55)のドーム内に吸入された冷媒は、そのドーム内の圧縮機構(図示は省略)で圧縮されてドーム内の空間に吐出される。冷凍用圧縮機(55)のドーム内は、高圧の冷媒が吐出される高圧部になる。この冷凍用圧縮機(55)は、高圧部であるドーム内の底部に冷凍機油が貯まるように構成されている。   The refrigeration compressor (55) is a variable-capacity high-pressure dome compressor, and is composed of an inverter compressor. An oil separator (64) is provided in the discharge pipe of the refrigeration compressor (55). The oil return pipe (65) of the oil separator (64) is connected to the suction pipe (68) of the refrigeration compressor (55). The oil return pipe (65) is provided with a capillary tube (69) as a pressure reducing mechanism. The refrigerant sucked into the dome of the refrigeration compressor (55) from the suction pipe (68) is compressed by a compression mechanism (not shown) in the dome and discharged into the space in the dome. The dome of the compressor for refrigeration (55) is a high-pressure part from which high-pressure refrigerant is discharged. The refrigeration compressor (55) is configured such that refrigeration oil is stored at the bottom of the dome, which is a high-pressure part.
そして、本発明の特徴として、図2に拡大して示すように、冷凍用圧縮機(55)の吐出配管における油分離器(64)の下流側には、減圧手段としての圧力調整弁(71)が設けられている。冷凍用圧縮機(55)から吐出された冷媒は、この圧力調整弁(71)を通過する際にその圧力が低下する。このため、第1及び第2圧縮機(11,12)の吸入側の圧力は、冷凍用圧縮機(55)のドーム内の圧力よりも低くなる。なお、減圧手段は、冷媒が流通する際に抵抗になるものであればよく、圧力調整弁(71)の他にキャピラリーチューブ、油分離器、フィルタ、マフラー、逆止弁、長い配管などを適用することができる。   As a feature of the present invention, as shown in an enlarged view in FIG. 2, a pressure regulating valve (71) as a decompression means is provided downstream of the oil separator (64) in the discharge pipe of the refrigeration compressor (55). ) Is provided. The refrigerant discharged from the refrigeration compressor (55) is reduced in pressure when passing through the pressure regulating valve (71). For this reason, the pressure on the suction side of the first and second compressors (11, 12) is lower than the pressure in the dome of the refrigeration compressor (55). The pressure reducing means only needs to be a resistance when the refrigerant flows. In addition to the pressure regulating valve (71), a capillary tube, an oil separator, a filter, a muffler, a check valve, a long pipe, etc. are applied. can do.
また、冷凍用圧縮機(55)のドームには、返油通路(72)の一端が接続されている。この接続位置は、ドーム内の冷凍機油が所定の高さHとなる位置に設定されている。返油通路(72)の他端は、圧力調整弁(71)をバイパスして冷媒配管(60)に接続されている。返油通路(72)には、電磁弁(73)が接続されている。なお、上記圧力調整弁(71)と返油通路(72)は、本発明に係る返油手段(70)を構成している。   One end of the oil return passageway (72) is connected to the dome of the refrigeration compressor (55). This connection position is set to a position where the refrigerator oil in the dome has a predetermined height H. The other end of the oil return passage (72) bypasses the pressure adjustment valve (71) and is connected to the refrigerant pipe (60). A solenoid valve (73) is connected to the oil return passage (72). The pressure regulating valve (71) and the oil return passage (72) constitute an oil return means (70) according to the present invention.
なお、図1の(CV)は逆止弁、(F)はフィルターである。   In FIG. 1, (CV) is a check valve, and (F) is a filter.
−冷凍装置の運転動作−
冷房運転のときには、四路切換弁(15)は第1ポートと第2ポートとが連通するとともに第3ポートと第4ポートとが連通する状態(第1状態)に設定される。室外ユニット(2)の電子膨張弁(27)は、全閉状態に設定される。そして、冷媒回路(6)の冷媒は、図1に矢印で示すように循環する。なお、暖房運転については、省略する。
-Operation of refrigeration equipment-
During the cooling operation, the four-way selector valve (15) is set to a state (first state) in which the first port and the second port communicate with each other and the third port and the fourth port communicate with each other. The electronic expansion valve (27) of the outdoor unit (2) is set to a fully closed state. And the refrigerant | coolant of a refrigerant circuit (6) circulates as shown by the arrow in FIG. The heating operation is omitted here.
具体的には、圧縮機(11,12)から吐出された冷媒は、室外熱交換器(13)において凝縮し、レシーバ(14)に流入する。レシーバ(14)内の冷媒は、室外ユニット(2)を流出した後、室内ユニット(3)と冷蔵ユニット(4)と冷凍ユニット(5)とに分流する。室内ユニット(3)に流入した冷媒は、室内電子膨張弁(43)によって減圧された後、室内熱交換器(42)において蒸発し、室内空気を冷却する。冷蔵ユニット(4)に流入した冷媒は、冷蔵用電子膨張弁(48)によって第1所定圧力PL1にまで減圧された後(図3参照)、冷蔵用冷却器(47)において蒸発し、庫内空気を冷却する。   Specifically, the refrigerant discharged from the compressors (11, 12) is condensed in the outdoor heat exchanger (13) and flows into the receiver (14). The refrigerant in the receiver (14) flows out of the outdoor unit (2), and then is divided into the indoor unit (3), the refrigeration unit (4), and the refrigeration unit (5). The refrigerant flowing into the indoor unit (3) is decompressed by the indoor electronic expansion valve (43), and then evaporated in the indoor heat exchanger (42) to cool the indoor air. The refrigerant flowing into the refrigeration unit (4) is depressurized to the first predetermined pressure PL1 by the refrigeration electronic expansion valve (48) (see FIG. 3), and then evaporated in the refrigeration cooler (47), Cool the air.
一方、冷凍ユニット(5)に流入した冷媒は、冷凍用電子膨張弁(57)によって、上記第1所定圧力PL1よりも低い第2所定圧力PL2にまで減圧される。減圧された冷媒は、冷凍用冷却器(56)において蒸発し、庫内空気を冷却する。冷凍用冷却器(56)を流出した冷媒は、冷凍用圧縮機(55)によって第1所定圧力PL1にまで昇圧され、冷蔵用冷却器(47)を流出した冷媒と合流し、室外ユニット(2)に流入する。室外ユニット(2)に流入した冷媒は、室内ユニット(3)から室外ユニット(2)に戻ってきた冷媒と合流し、圧縮機(11,12)に吸入される。   On the other hand, the refrigerant flowing into the refrigeration unit (5) is depressurized by the refrigeration electronic expansion valve (57) to a second predetermined pressure PL2 lower than the first predetermined pressure PL1. The decompressed refrigerant evaporates in the refrigeration cooler (56) to cool the internal air. The refrigerant that has flowed out of the refrigeration cooler (56) is boosted to the first predetermined pressure PL1 by the refrigeration compressor (55), and merges with the refrigerant that has flowed out of the refrigeration cooler (47). ). The refrigerant that has flowed into the outdoor unit (2) joins the refrigerant that has returned from the indoor unit (3) to the outdoor unit (2), and is sucked into the compressors (11, 12).
圧縮機(11,12)に吸入された冷媒は、当該圧縮機(11,12)によって圧縮され、再び上記の循環動作を繰り返す。以上の運転によって、冷媒回路(6)においては、図3に示すような2段圧縮式冷凍サイクルが形成される。   The refrigerant sucked into the compressor (11, 12) is compressed by the compressor (11, 12) and repeats the circulation operation again. With the above operation, a two-stage compression refrigeration cycle as shown in FIG. 3 is formed in the refrigerant circuit (6).
冷凍ユニット(5)において、油分離器(64)が捕集した冷凍機油は、油戻し管(65)を通じて吸入配管(68)に戻り、冷凍用圧縮機(55)に回収される。   In the refrigeration unit (5), the refrigeration oil collected by the oil separator (64) returns to the suction pipe (68) through the oil return pipe (65) and is collected by the refrigeration compressor (55).
そして、圧力調整弁(71)により、高段圧縮機(11,12)の吸入側は低段圧縮機(55)のドーム内よりも低圧になっている。このため、電磁弁(73)を開くと、ドーム内に所定高さHよりも高い位置まで貯まった冷凍機油は、圧力調整弁(71)をバイパスする返油通路(72)を通って第1及び第2圧縮機(11,12)の吸入側に押し出される。したがって、冷凍用圧縮機(55)のドーム内の冷凍機油の液面の高さが所定高さHよりも高くならないように維持されると共に、第1及び第2圧縮機(11,12)内の冷凍機油が欠乏することが防止される。   The suction side of the high stage compressor (11, 12) is at a lower pressure than the inside of the dome of the low stage compressor (55) by the pressure regulating valve (71). For this reason, when the solenoid valve (73) is opened, the refrigeration oil stored in the dome up to a position higher than the predetermined height H passes through the oil return passage (72) bypassing the pressure regulating valve (71) to the first. And pushed out to the suction side of the second compressor (11, 12). Accordingly, the liquid level of the refrigeration oil in the dome of the refrigeration compressor (55) is maintained so as not to be higher than the predetermined height H, and the first and second compressors (11, 12) are maintained. Deficiency of the refrigerator oil is prevented.
−実施形態の効果−
したがって、本実施形態によると、返油手段(70)により、冷凍用圧縮機(55)のドーム内に貯まった冷凍機油を第1及び第2圧縮機(11,12)に戻すようにしている。このため、第1及び第2圧縮機(11,12)内の冷凍機油が欠乏することはないので、新たに冷凍機油を充填する必要がない。よって、冷凍機油を充填する手間がかからない。また、冷凍用圧縮機(55)に冷凍機油が所定高さH以上に貯まってしまうことを防止できるので、冷凍用圧縮機(55)内で冷凍機油による回転抵抗が減り、運転効率が良くなる。
-Effect of the embodiment-
Therefore, according to this embodiment, the oil return means (70) returns the refrigeration oil stored in the dome of the refrigeration compressor (55) to the first and second compressors (11, 12). . For this reason, since the refrigerating machine oil in the first and second compressors (11, 12) is not deficient, there is no need to newly fill the refrigerating machine oil. Therefore, it does not take time to fill the refrigerating machine oil. Further, since the refrigerating machine oil (55) can be prevented from storing the refrigerating machine oil at a predetermined height H or more, the rotational resistance due to the refrigerating machine oil is reduced in the refrigerating compressor (55), and the operation efficiency is improved. .
また、圧力調整弁(71)を冷凍用圧縮機(55)の吐出側に設け、第1及び第2圧縮機(11,12)の吸入側を冷凍用圧縮機(55)のドーム内よりも低圧にするとともに、返油通路(72)の一端を冷凍用圧縮機(55)のドームに接続し、他端を圧力調整弁(71)をバイパスして第1及び第2圧縮機(11,12)の吸入側に接続することにより、冷凍用圧縮機(55)のドーム内に貯まった冷凍機油を第1及び第2圧縮機(11,12)に戻すようにしている。このため、簡単な構成により、冷凍機油を充填する手間がかからず、最少の冷凍機油で効率よく運転が行われる冷凍装置が得られる。   In addition, a pressure regulating valve (71) is provided on the discharge side of the refrigeration compressor (55), and the suction side of the first and second compressors (11, 12) is located more than in the dome of the refrigeration compressor (55). While the pressure is reduced, one end of the oil return passage (72) is connected to the dome of the refrigeration compressor (55), and the other end is bypassed the pressure regulating valve (71) and the first and second compressors (11, 11) By connecting to the suction side of 12), the refrigeration oil stored in the dome of the refrigeration compressor (55) is returned to the first and second compressors (11, 12). For this reason, with a simple configuration, it is possible to obtain a refrigeration apparatus that can be efficiently operated with the minimum amount of refrigerating machine oil without the need for filling the refrigerating machine oil.
−実施形態の変形例1−
実施形態の変形例1について説明する。この変形例1の冷凍装置(1)の冷媒回路図を図4に示す。この変形例1の冷凍装置(1)は、返油通路(72)の接続位置が上記実施形態とは異なっている。
-Modification 1 of embodiment-
A first modification of the embodiment will be described. FIG. 4 shows a refrigerant circuit diagram of the refrigeration apparatus (1) of the first modification. In the refrigeration apparatus (1) of the first modification, the connection position of the oil return passage (72) is different from that of the above embodiment.
具体的に、返油通路(72)は、一端が油分離器(64)に接続された油戻し管(65)に接続され、他端が圧力調整弁(71)をバイパスして冷媒配管(60)に接続されている。返油通路(72)には、上記実施形態と同様に、電磁弁(73)が設けられている。また、油戻し管(65)には、上記実施形態とは異なり、電磁弁(66)が設けられている。   Specifically, one end of the oil return passage (72) is connected to the oil return pipe (65) connected to the oil separator (64), and the other end bypasses the pressure adjustment valve (71) and is connected to the refrigerant pipe ( 60) connected. The oil return passage (72) is provided with a solenoid valve (73) as in the above embodiment. Further, unlike the above embodiment, the oil return pipe (65) is provided with a solenoid valve (66).
この変形例1では、油分離器(64)が捕集した冷凍機油を冷凍用圧縮機(55)か第1及び第2圧縮機(11,12)のどちらかに戻すように、油戻し管(65)の電磁弁(66)と返油通路(72)の電磁弁(73)とが制御される。具体的に、油分離器(64)の冷凍機油を冷凍用圧縮機(55)へ戻す際は、油戻し管(65)の電磁弁(66)を開口し、返油通路(72)の電磁弁(73)を閉鎖する。油分離器(64)の冷凍機油を第1及び第2圧縮機(11,12)へ戻す際は、油戻し管(65)の電磁弁(66)を閉鎖し、返油通路(72)の電磁弁(73)を開口する。   In this modified example 1, the oil return pipe is arranged so that the refrigeration oil collected by the oil separator (64) is returned to either the refrigeration compressor (55) or the first and second compressors (11, 12). The electromagnetic valve (66) of (65) and the electromagnetic valve (73) of the oil return passage (72) are controlled. Specifically, when returning the refrigeration oil of the oil separator (64) to the refrigeration compressor (55), the solenoid valve (66) of the oil return pipe (65) is opened, and the solenoid of the oil return passage (72) is opened. Close the valve (73). When returning the refrigeration oil of the oil separator (64) to the first and second compressors (11, 12), the solenoid valve (66) of the oil return pipe (65) is closed and the oil return passage (72) Open the solenoid valve (73).
−実施形態の変形例2−
実施形態の変形例2について説明する。この変形例2の冷凍装置(1)の冷媒回路図を図5に示す。この変形例2の冷凍装置(1)は、返油手段(70)が第1返油通路(72a)と第2返油通路(72b)とを備えている。第1返油通路(72a)の接続位置は上記実施形態と同じであり、第2返油通路(72b)の接続位置は上記変形例1と同じである。
-Modification 2 of embodiment-
A second modification of the embodiment will be described. FIG. 5 shows a refrigerant circuit diagram of the refrigeration apparatus (1) of the second modification. In the refrigeration apparatus (1) of Modification 2, the oil return means (70) includes a first oil return passage (72a) and a second oil return passage (72b). The connection position of the first oil return passage (72a) is the same as that in the above embodiment, and the connection position of the second oil return passage (72b) is the same as that in the first modification.
この変形例2では、返油手段(70)により冷凍機油を冷凍用圧縮機(55)から第1及び第2圧縮機(11,12)へ戻すにあたって、通常は第1返油通路(72a)を使用する。つまり、第1返油通路(72a)の電磁弁(73a)を開口して、第2返油通路(72b)の電磁弁(73b)は閉鎖する。第2返油通路(72b)は、第1返油通路(72a)の電磁弁(73a)が故障した場合などに使用する。   In this modified example 2, when returning the refrigeration oil from the refrigeration compressor (55) to the first and second compressors (11, 12) by the oil return means (70), the first oil return passage (72a) is usually used. Is used. That is, the electromagnetic valve (73a) of the first oil return passage (72a) is opened, and the electromagnetic valve (73b) of the second oil return passage (72b) is closed. The second oil return passage (72b) is used when the solenoid valve (73a) of the first oil return passage (72a) fails.
−実施形態の変形例3−
実施形態の変形例3について説明する。この変形例3の冷凍装置(1)の冷媒回路図を図6に示す。この変形例3の冷凍装置(1)は、上記実施形態とは異なり、冷凍ユニット(5)の低段圧縮機が複数台の冷凍用圧縮機(55a,55b,55c)で構成されている。なお、この変形例3では冷媒回路(6)に3台の冷凍用圧縮機(55a,55b,55c)を設けているが、この冷凍用圧縮機(55a,55b,55c)の台数は単なる例示であり、2台あるいは4台以上の冷凍用圧縮機(55a,55b,55c)を冷媒回路(6)に設けてもよい。
—Modification 3 of Embodiment—
A modification 3 of the embodiment will be described. FIG. 6 shows a refrigerant circuit diagram of the refrigeration apparatus (1) of the third modification. In the refrigeration apparatus (1) of Modification 3, unlike the above embodiment, the low-stage compressor of the refrigeration unit (5) is composed of a plurality of refrigeration compressors (55a, 55b, 55c). In this modification 3, the refrigerant circuit (6) is provided with three refrigeration compressors (55a, 55b, 55c), but the number of refrigeration compressors (55a, 55b, 55c) is merely an example. Two or four or more refrigeration compressors (55a, 55b, 55c) may be provided in the refrigerant circuit (6).
具体的に、冷凍ユニット(5)には、第1冷凍用圧縮機(55a)と第2冷凍用圧縮機(55b)と第3冷凍用圧縮機(55c)とが、冷凍用冷却器(56)と油分離器(64)との間に互いに並列に接続されている。各冷凍用圧縮機(55a,55b,55c)の吐出側の冷媒配管は、合流して油分離器(64)に接続されている。各冷凍用圧縮機(55a,55b,55c)の吸入側には、一端が冷凍用冷却器(56)に接続された吸入配管(68)から分岐した冷媒配管が接続されている。   Specifically, the refrigeration unit (5) includes a first refrigeration compressor (55a), a second refrigeration compressor (55b), and a third refrigeration compressor (55c). ) And the oil separator (64). The refrigerant pipes on the discharge side of the refrigeration compressors (55a, 55b, 55c) are joined and connected to the oil separator (64). A refrigerant pipe branching from a suction pipe (68) having one end connected to the refrigeration cooler (56) is connected to the suction side of each refrigeration compressor (55a, 55b, 55c).
図6における左側の第1冷凍用圧縮機(55a)の吸入側の冷媒配管と中央の第2冷凍用圧縮機(55b)のドームとは、第1均油管(67a)で接続され、第2冷凍用圧縮機(55b)の吸入側の冷媒配管と右側の第3冷凍用圧縮機(55c)のドームとは、第2均油管(67b)で接続されている。これら均油管(67a,67b)は、第2,第3冷凍用圧縮機(55b,55c)から第1冷凍用圧縮機(55a)へ冷凍機油を戻すための返油通路を構成している。第2冷凍用圧縮機(55b)及び第3冷凍用圧縮機(55c)のドームにおける均油管(67a,67b)の接続位置は、ドーム内の冷凍機油が所定の高さHとなる位置に設定されている。各均油管(67a,67b)には、電磁弁(74a,74b)がそれぞれ設けられている。   The refrigerant pipe on the suction side of the first refrigeration compressor (55a) on the left side in FIG. 6 and the dome of the second refrigeration compressor (55b) on the center are connected by a first oil equalizing pipe (67a), and the second The refrigerant pipe on the suction side of the refrigeration compressor (55b) and the dome of the third refrigeration compressor (55c) on the right side are connected by a second oil leveling pipe (67b). These oil equalizing pipes (67a, 67b) constitute an oil return passage for returning the refrigeration oil from the second and third refrigeration compressors (55b, 55c) to the first refrigeration compressor (55a). The connection position of the oil equalizing pipes (67a, 67b) in the dome of the second refrigeration compressor (55b) and the third refrigeration compressor (55c) is set to a position where the refrigeration oil in the dome has a predetermined height H. Has been. Each oil equalizing pipe (67a, 67b) is provided with a solenoid valve (74a, 74b).
返油通路(72)は、第1冷凍用圧縮機(55a)のドームに接続されている。この第1冷凍用圧縮機(55a)は、返油対象の低段側圧縮機を構成している。第1冷凍用圧縮機(55a)における返油通路(72)の接続位置は、上記実施形態と同様に、ドーム内の冷凍機油が所定の高さHとなる位置に設定されている。返油通路(72)の他端は、圧力調整弁(71)をバイパスして冷媒配管(60)に接続されている。   The oil return passage (72) is connected to the dome of the first refrigeration compressor (55a). This 1st freezing compressor (55a) comprises the low stage side compressor of the oil return object. The connection position of the oil return passageway (72) in the first refrigeration compressor (55a) is set to a position where the refrigeration oil in the dome has a predetermined height H as in the above embodiment. The other end of the oil return passage (72) bypasses the pressure adjustment valve (71) and is connected to the refrigerant pipe (60).
油戻し管(65)は、第3冷凍用圧縮機(55c)の吸入側の冷媒配管に接続されている。油分離器(64)で冷媒から分離された冷凍機油は、この油戻し管(65)を通って第3冷凍用圧縮機(55c)の吸入側の冷媒配管へ送り込まれ、冷媒と共に第3冷凍用圧縮機(55c)へ吸入される。   The oil return pipe (65) is connected to the refrigerant pipe on the suction side of the third refrigeration compressor (55c). The refrigeration oil separated from the refrigerant in the oil separator (64) is sent to the refrigerant pipe on the suction side of the third refrigeration compressor (55c) through the oil return pipe (65), and the third refrigeration together with the refrigerant. Into the compressor (55c).
この変形例3では、各冷凍用圧縮機(55a,55b,55c)内の冷凍機油の量を均一化する際に、電磁弁(74a,74b)が使用される。第2均油管(67b)の電磁弁(74b)が開くと、第3冷凍用圧縮機(55c)のドーム内において所定高さHよりも高い位置まで貯まった冷凍機油は、第2均油管(67b)を通って第2冷凍用圧縮機(55b)の吸入側の冷媒配管へ流入し、冷媒と共に第2冷凍用圧縮機(55b)へ吸入される。一方、第1均油管(67a)の電磁弁(74a)が開くと、第2冷凍用圧縮機(55b)のドーム内において所定高さHよりも高い位置まで貯まった冷凍機油は、第1均油管(67a)を通って第1冷凍用圧縮機(55a)の吸入側の冷媒配管へ流入し、冷媒と共に第1冷凍用圧縮機(55a)へ吸入される。   In the third modification, the solenoid valves (74a, 74b) are used when equalizing the amount of the refrigeration oil in the refrigeration compressors (55a, 55b, 55c). When the solenoid valve (74b) of the second oil leveling pipe (67b) is opened, the refrigerating machine oil stored up to a position higher than the predetermined height H in the dome of the third freezing compressor (55c) is transferred to the second oil leveling pipe ( 67b) and flows into the refrigerant piping on the suction side of the second refrigeration compressor (55b), and is sucked together with the refrigerant into the second refrigeration compressor (55b). On the other hand, when the solenoid valve (74a) of the first oil leveling pipe (67a) is opened, the refrigerating machine oil stored up to a position higher than the predetermined height H in the dome of the second refrigeration compressor (55b) The oil flows into the refrigerant pipe on the suction side of the first refrigeration compressor (55a) through the oil pipe (67a), and is sucked into the first refrigeration compressor (55a) together with the refrigerant.
また、この変形例3では、上記実施形態と同様に、第1冷凍用圧縮機(55a)から第1及び第2圧縮機(11,12)へ冷凍機油を戻す際に、返油通路(72)の電磁弁(73)を使用する。電磁弁(73)が開くと、第1冷凍用圧縮機(55a)のドーム内において所定高さHよりも高い位置まで貯まった冷凍機油は、圧力調整弁(71)をバイパスする返油通路(72)を通って第1及び第2圧縮機(11,12)の吸入側に送り出される。   In the third modification, as in the above embodiment, when returning the refrigeration oil from the first refrigeration compressor (55a) to the first and second compressors (11, 12), the oil return passageway (72 ) Solenoid valve (73). When the solenoid valve (73) is opened, the refrigeration oil stored up to a position higher than the predetermined height H in the dome of the first refrigeration compressor (55a) is returned to the oil return passage (bypassing the pressure regulating valve (71)) ( 72) through the suction side of the first and second compressors (11, 12).
このように、この変形例3では、第2冷凍用圧縮機(55b)や第3冷凍用圧縮機(55c)のドーム内に溜まった冷凍機油が第1冷凍用圧縮機(55a)へ一旦集められ、この第1冷凍用圧縮機(55a)に集まった冷凍機油が高段側の第1,第2圧縮機(11,12)へ送り返される。   Thus, in this modification 3, the refrigerating machine oil collected in the dome of the 2nd freezing compressor (55b) or the 3rd freezing compressor (55c) is once collected in the 1st freezing compressor (55a). The refrigeration oil collected in the first refrigeration compressor (55a) is sent back to the first and second compressors (11, 12) on the higher stage side.
なお、本変形例では、図7に示すように、油戻し管(65)を第2冷凍用圧縮機(55b)の吸入側の冷媒配管に接続してもよい。同図に示す冷媒回路(6)において、第2冷凍用圧縮機(55b)及び第3冷凍用圧縮機(55c)は、何れも容量が固定の定速圧縮機である。また、この冷媒回路(6)において、第2均油管(67b)の出口側の端部は、第1均油管(67a)における電磁弁(74a)の下流側に接続されている。この冷媒回路(6)では、第1均油管(67a)の電磁弁(74a)が開くと、第2冷凍用圧縮機(55b)のドーム内の冷凍機油が第1冷凍用圧縮機(55a)の吸入側へ送られる。また、第2均油管(67b)の電磁弁(74b)が開くと、第3冷凍用圧縮機(55c)のドーム内の冷凍機油が第1冷凍用圧縮機(55a)の吸入側へ送られる。また、油分離器(64)で冷媒から分離された冷凍機油は、油戻し管(65)を通って第2冷凍用圧縮機(55b)の吸入側の冷媒配管へ送り込まれ、冷媒と共に第2冷凍用圧縮機(55b)へ吸入される。   In this modification, as shown in FIG. 7, the oil return pipe (65) may be connected to the refrigerant pipe on the suction side of the second refrigeration compressor (55b). In the refrigerant circuit (6) shown in the figure, the second refrigeration compressor (55b) and the third refrigeration compressor (55c) are both constant speed compressors having a fixed capacity. In the refrigerant circuit (6), the end of the second oil equalizing pipe (67b) on the outlet side is connected to the downstream side of the electromagnetic valve (74a) in the first oil equalizing pipe (67a). In the refrigerant circuit (6), when the solenoid valve (74a) of the first oil equalizing pipe (67a) is opened, the refrigeration oil in the dome of the second refrigeration compressor (55b) is transferred to the first refrigeration compressor (55a). To the inhalation side. When the solenoid valve (74b) of the second oil equalizing pipe (67b) is opened, the refrigeration oil in the dome of the third refrigeration compressor (55c) is sent to the suction side of the first refrigeration compressor (55a). . The refrigerating machine oil separated from the refrigerant in the oil separator (64) is sent to the refrigerant pipe on the suction side of the second refrigerating compressor (55b) through the oil return pipe (65), and the second oil is supplied together with the refrigerant. It is sucked into the refrigeration compressor (55b).
−その他の実施形態−
本発明は、上記実施形態について、以下のような構成としてもよい。
-Other embodiments-
The present invention may be configured as follows with respect to the above embodiment.
すなわち、本実施形態では、冷凍装置(1)は、室外ユニット(2)と、室内ユニット(3)と、冷蔵ユニット(4)と、冷凍ユニット(5)とが接続されてなる冷媒回路(6)を備えるものとしたが、低段圧縮機(55)と高段圧縮機(11,12)とが直列に接続されて二段圧縮冷凍サイクルを行う冷媒回路(6)を備えた冷凍装置であれば本発明は適用できる。   That is, in this embodiment, the refrigeration apparatus (1) includes a refrigerant circuit (6) in which an outdoor unit (2), an indoor unit (3), a refrigeration unit (4), and a refrigeration unit (5) are connected. ) With a refrigerant circuit (6) in which a low-stage compressor (55) and a high-stage compressor (11, 12) are connected in series to perform a two-stage compression refrigeration cycle. The present invention can be applied if it exists.
以上説明したように、本発明は、コンビニエンスストアやスーパーマーケット等に配置され、二段圧縮冷凍サイクルを行う冷媒回路を備えた冷凍装置について有用である。   As described above, the present invention is useful for a refrigeration apparatus including a refrigerant circuit that is arranged in a convenience store, a supermarket, or the like and performs a two-stage compression refrigeration cycle.
本発明の実施形態にかかる冷凍装置の冷媒回路図である。It is a refrigerant circuit figure of the refrigerating device concerning the embodiment of the present invention. 返油手段の拡大図である。It is an enlarged view of an oil return means. 実施形態にかかる冷凍サイクルのモリエル線図である。It is a Mollier diagram of the refrigerating cycle concerning an embodiment. 本発明の実施形態の変形例1にかかる冷凍装置の冷媒回路図である。It is a refrigerant circuit figure of the freezing apparatus concerning the modification 1 of embodiment of this invention. 本発明の実施形態の変形例2にかかる冷凍装置の冷媒回路図である。It is a refrigerant circuit figure of the freezing apparatus concerning the modification 2 of embodiment of this invention. 本発明の実施形態の変形例3にかかる冷凍装置の冷媒回路図である。It is a refrigerant circuit figure of the freezing apparatus concerning the modification 3 of embodiment of this invention. 本発明の実施形態の変形例3にかかる冷凍装置の冷媒回路図である。It is a refrigerant circuit figure of the freezing apparatus concerning the modification 3 of embodiment of this invention.
符号の説明Explanation of symbols
6 冷媒回路
11 第1圧縮機(高段圧縮機)
12 第2圧縮機(高段圧縮機)
55 冷凍用圧縮機(低段圧縮機)
55a 第1冷凍用圧縮機(低段圧縮機)
55b 第2冷凍用圧縮機(低段圧縮機)
55c 第3冷凍用圧縮機(低段圧縮機)
64 油分離器
67a 第1均油管(送油通路)
67b 第2均油管(送油通路)
70 返油手段
71 圧力調整弁(減圧手段)
72 返油通路
6 Refrigerant circuit
11 First compressor (high stage compressor)
12 Second compressor (high stage compressor)
55 Refrigeration compressor (low stage compressor)
55a First refrigeration compressor (low stage compressor)
55b Second refrigeration compressor (low stage compressor)
55c Third refrigeration compressor (low stage compressor)
64 oil separator
67a 1st oil leveling pipe (oil feed passage)
67b Second oil level pipe (oil feed passage)
70 Oil return means
71 Pressure regulating valve (pressure reducing means)
72 Oil return passage

Claims (7)

  1. 低段圧縮機(55)と高段圧縮機(11,12)とが直列に接続されて二段圧縮冷凍サイクルを行う冷媒回路(6)を備えた冷凍装置であって、
    冷凍機油を上記低段圧縮機(55)から上記高段圧縮機(11,12)に戻す返油手段(70)を備えている
    ことを特徴とする冷凍装置。
    A refrigeration apparatus comprising a refrigerant circuit (6) in which a low-stage compressor (55) and a high-stage compressor (11, 12) are connected in series to perform a two-stage compression refrigeration cycle,
    A refrigeration apparatus comprising oil return means (70) for returning refrigeration oil from the low stage compressor (55) to the high stage compressor (11, 12).
  2. 請求項1に記載の冷凍装置において、
    上記低段圧縮機(55)は、その高圧部に冷凍機油が貯まるように構成される一方、
    上記返油手段(70)は、低段圧縮機(55)の高圧部に貯まった冷凍機油を上記高段圧縮機(11,12)に戻す
    ことを特徴とする冷凍装置。
    The refrigeration apparatus according to claim 1,
    The low-stage compressor (55) is configured to store refrigeration oil in its high-pressure section,
    The refrigeration apparatus, wherein the oil return means (70) returns the refrigeration oil stored in the high pressure portion of the low stage compressor (55) to the high stage compressor (11, 12).
  3. 請求項2に記載の冷凍装置において、
    上記返油手段(70)は、上記低段圧縮機(55)の吐出側に設けられ、高段圧縮機(11,12)の吸入側を低段圧縮機(55)の高圧部よりも低圧にするための減圧手段(71)と、一端が低段圧縮機(55)の高圧部に接続されると共に、他端が減圧手段(71)をバイパスして高段圧縮機(11,12)の吸入側に接続される返油通路(72)とを備えている
    ことを特徴とする冷凍装置。
    The refrigeration apparatus according to claim 2,
    The oil return means (70) is provided on the discharge side of the low stage compressor (55), and the suction side of the high stage compressor (11, 12) is lower in pressure than the high pressure section of the low stage compressor (55). Pressure reducing means (71) and one end connected to the high pressure section of the low stage compressor (55), and the other end bypassing the pressure reducing means (71) and the high stage compressor (11, 12) And a return oil passage (72) connected to the suction side of the refrigeration apparatus.
  4. 請求項1に記載の冷凍装置において、
    上記低段圧縮機(55)は、高圧空間となるドーム内に冷凍機油が貯まるように構成される一方、
    上記返油手段(70)は、上記低段圧縮機(55)のドーム内に貯まった冷凍機油を上記高段圧縮機(11,12)に戻す
    ことを特徴とする冷凍装置。
    The refrigeration apparatus according to claim 1,
    The low-stage compressor (55) is configured such that refrigeration oil is stored in a dome serving as a high-pressure space,
    The refrigeration apparatus, wherein the oil return means (70) returns the refrigeration oil stored in the dome of the low stage compressor (55) to the high stage compressor (11, 12).
  5. 請求項4に記載の冷凍装置において、
    上記返油手段(70)は、上記低段圧縮機(55)の吐出側に設けられ、高段圧縮機(11,12)の吸入側を低段圧縮機(55)のドーム内よりも低圧にするための減圧手段(71)と、一端が低段圧縮機(55)のドームに接続されると共に、他端が減圧手段(71)をバイパスして高段圧縮機(11,12)の吸入側に接続される返油通路(72)とを備えている
    ことを特徴とする冷凍装置。
    The refrigeration apparatus according to claim 4,
    The oil return means (70) is provided on the discharge side of the low stage compressor (55), and the suction side of the high stage compressor (11, 12) has a lower pressure than the dome of the low stage compressor (55). And one end of the decompression means (71) is connected to the dome of the low stage compressor (55), and the other end of the high stage compressor (11, 12) bypasses the decompression means (71). A refrigeration apparatus comprising an oil return passage (72) connected to the suction side.
  6. 請求項2,3,4又は5に記載の冷凍装置において、
    上記低段圧縮機(55a,55b,55c)が複数設けられ、該複数の低段圧縮機(55a,55b,55c)が互いに並列に接続されており、
    上記返油手段(70)は、上記複数の低段圧縮機(55a,55b,55c)のうちの1台である返油対象の低段圧縮機(55a)から上記高段圧縮機(11,12)へ冷凍機油を戻すように構成される一方、
    上記返油対象の低段圧縮機(55a)以外の低段圧縮機(55b,55c)から該返油対象の低段圧縮機(55a)へ冷凍機油を送るための送油通路(67a,67b)を備えていることを特徴とする冷凍装置。
    The refrigeration apparatus according to claim 2, 3, 4 or 5,
    A plurality of the low stage compressors (55a, 55b, 55c) are provided, and the plurality of low stage compressors (55a, 55b, 55c) are connected in parallel to each other,
    The oil return means (70) includes a low-stage compressor (55a) that is one of the plurality of low-stage compressors (55a, 55b, 55c) and a high-stage compressor (11, 12) While configured to return refrigeration oil to
    Oil supply passage (67a, 67b) for sending refrigeration oil from the low stage compressor (55b, 55c) other than the low stage compressor (55a) to be returned to the low stage compressor (55a) to be returned A refrigeration apparatus comprising:
  7. 請求項1に記載の冷凍装置において、
    上記低段圧縮機(55)の吐出側には、低段圧縮機(55)から吐出された冷凍機油を捕集する油分離器(64)が設けられる一方、
    上記返油手段(70)は、上記高段圧縮機(11,12)の吸入側を上記油分離器(64)内よりも低圧にするために油分離器(64)よりも高段圧縮機(11,12)側に設けられる減圧手段(71)と、一端が油分離器(64)に接続されると共に、他端が減圧手段(71)をバイパスして高段圧縮機(11,12)の吸入側に接続される返油通路(72)とを備えている
    ことを特徴とする冷凍装置。
    The refrigeration apparatus according to claim 1,
    On the discharge side of the low-stage compressor (55), an oil separator (64) that collects refrigeration oil discharged from the low-stage compressor (55) is provided,
    The oil return means (70) has a higher stage compressor than the oil separator (64) in order to make the suction side of the higher stage compressor (11, 12) at a lower pressure than in the oil separator (64). The decompression means (71) provided on the (11, 12) side and one end of the decompression means (71) are connected to the oil separator (64), and the other end bypasses the decompression means (71). And an oil return passage (72) connected to the suction side.
JP2005254657A 2004-09-02 2005-09-02 Refrigeration equipment Expired - Fee Related JP3861913B1 (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009028193A1 (en) 2007-08-28 2009-03-05 Daikin Industries, Ltd. Refrigeration device
US8141376B2 (en) 2007-03-15 2012-03-27 Lg Electronics Inc. Air conditioning system having a pressure compensation device
CN103292520A (en) * 2013-06-18 2013-09-11 宁波奥克斯电气有限公司 Multi-split air conditioner system oil balancing device and control method
JP2016161190A (en) * 2015-02-27 2016-09-05 ダイキン工業株式会社 Refrigerating device and heat pump
WO2020132348A3 (en) * 2018-12-19 2020-10-15 Emerson Climate Technologies, Inc. Oil control for climate-control system

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JPH04371759A (en) * 1991-06-21 1992-12-24 Hitachi Ltd Freezing cycle of two-stage compression and two-stage expansion
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Publication number Priority date Publication date Assignee Title
US8141376B2 (en) 2007-03-15 2012-03-27 Lg Electronics Inc. Air conditioning system having a pressure compensation device
WO2009028193A1 (en) 2007-08-28 2009-03-05 Daikin Industries, Ltd. Refrigeration device
US8408018B2 (en) 2007-08-28 2013-04-02 Daikin Industries, Ltd. Refrigeration apparatus
CN103292520A (en) * 2013-06-18 2013-09-11 宁波奥克斯电气有限公司 Multi-split air conditioner system oil balancing device and control method
JP2016161190A (en) * 2015-02-27 2016-09-05 ダイキン工業株式会社 Refrigerating device and heat pump
WO2020132348A3 (en) * 2018-12-19 2020-10-15 Emerson Climate Technologies, Inc. Oil control for climate-control system

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