JP2001124388A - Air-conditioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air-conditioning device capable of improving durability of a sensor and accurately detecting an oil amount. SOLUTION: Oil separators 12a and 12b and compressors 11a and 11b are intercoupled through constant oil return pipes 21a and 21b. Sensors Sa and Sb to detect an oil level M in an oil separator to return oil through the constant oil return pipes are situated in the oil separators 12a and 12b. When it is detected by the sensors that an oil amount in the oil separators 12a and 12b is an oil amount lower than the oil level M, it is estimated that an oil amount in an outdoor unit is insufficient and oil from ether outdoor unit is recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner in which a plurality of outdoor units are connected in parallel to an interunit pipe extending from an indoor unit.

[0002]

2. Description of the Related Art Generally, there are provided a plurality of outdoor units having an outdoor heat exchanger, a compressor and an oil separator, and returning oil separated by the oil separator to the compressor via a return pipe. The outdoor unit is connected in parallel to the piping between the units extending from the indoor unit, and the oil amount in each outdoor unit is measured.If the oil amount in any one of the outdoor units is insufficient, the oil is collected from the other outdoor unit and collected. 2. Description of the Related Art An air conditioner provided with a means for balancing an oil amount between outdoor units is known (Japanese Patent Laid-Open No. 5-240520).

[0003] In this type, conventionally, an oil level sensor is attached to a compressor, and when the oil level detected by the oil level sensor falls below a predetermined oil level, the amount of oil in the outdoor unit is reduced. It is configured to operate means for balancing the amount of oil between the outdoor units as a shortage.

[0004]

However, in the conventional configuration, since the oil level sensor is attached to the compressor, when the vibration of the compressor is large, for example, in the case of an engine driven compressor, the vibration is reduced. This greatly affects the durability of the oil level sensor, and causes a problem that the oil amount cannot be accurately detected.

Accordingly, an object of the present invention is to solve the above-described problems of the prior art, improve the durability of the sensor, and provide an air-equipped air sensor having a sensor capable of accurately detecting the amount of oil. It is to provide a harmony device.

[0006]

According to the first aspect of the present invention,
An outdoor heat exchanger, a compressor, and an oil separator; a plurality of outdoor units that return the oil separated by the oil separator to the compressor via a return pipe; and extend these outdoor units from the indoor unit. In addition to connecting the units in parallel, measure the amount of oil in each outdoor unit.If the amount of oil in one of the outdoor units is insufficient, collect the oil from the other outdoor unit and reduce the amount of oil between the outdoor units. In the air conditioner provided with a balancing means, a sensor for measuring an oil amount in the outdoor unit is provided on the oil separator.

According to a second aspect of the present invention, there is provided an outdoor heat exchanger, a compressor, and an oil separator, and a plurality of outdoor units for returning the oil separated by the oil separator to the compressor via a return pipe. These outdoor units are connected in parallel to the piping between the units extending from the indoor units, and the oil amount in each outdoor unit is measured.If the oil amount in one of the outdoor units becomes insufficient, the oil from the other outdoor unit is supplied. In an air conditioner provided with a means for collecting and balancing the amount of oil between the outdoor units, the oil separator and the compressor are always connected with an oil return pipe, and the oil is always returned by the oil return pipe. A sensor for detecting the oil level in the possible first-level oil separator is provided on the oil separator, and the sensor is used to detect the oil level. If the amount of oil in the separator is detected to be less than the oil level of the first level, it is assumed that the amount of oil in the outdoor unit is insufficient, and oil is collected from another outdoor unit. It is characterized by.

According to a third aspect of the present invention, there is provided an outdoor unit having an outdoor heat exchanger, a compressor, and an oil separator, wherein a plurality of outdoor units return the oil separated by the oil separator to the compressor via a return pipe. These outdoor units are connected in parallel to the piping between the units extending from the indoor units, and the oil amount in each outdoor unit is measured.If the oil amount in one of the outdoor units becomes insufficient, the oil from the other outdoor unit is supplied. In the air conditioner provided with a means for collecting and balancing the oil amount between the outdoor units, the oil separator and the compressor are connected by a forced oil return pipe and a constant oil return pipe. A sensor for detecting the oil level in the first-level oil separator capable of returning oil in the pipe is provided in the oil separator, When the sensor detects that the oil amount in the oil separator is equal to or less than the oil level of the first level, it is presumed that the oil amount in the outdoor unit is insufficient, and the oil is removed from another outdoor unit. While collecting, at the time of starting the compressor, when the rotation speed of the compressor is unstable, or when the oil amount in the oil separator is equal to or less than the second level oil level lower than the first level oil level, It is characterized in that the oil in its own oil separator is returned to the compressor through a forced oil return pipe.

According to a fourth aspect of the present invention, there is provided an oil level sensor according to the second or third aspect, wherein the sensor is capable of detecting an oil level in an oil separator in which oil can always be returned by an oil return pipe. It is characterized by the following.

[0010]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 1a and 1b denote outdoor units, and 3a and 3b denote indoor units. The outdoor unit 1a includes an accumulator 10a, a compressor 11a driven by a gas engine, and an oil separator 12a.
a, a four-way valve 13a, an outdoor heat exchanger 14a, and an outdoor electric expansion valve 15a. In addition, 17a is a fan of the outdoor heat exchanger 14a. Outdoor unit 1b
Is the same as that of the outdoor unit 1a, including the following configuration, and the description thereof is omitted.

The indoor unit 3a includes an indoor heat exchanger 34a and an indoor electric expansion valve 35a (hereinafter, referred to as an "indoor mechanical valve 35a"). Note that the indoor unit 3b is the same as the indoor unit 3a, including the following configuration, and a description thereof will be omitted. From this indoor unit 3a, 3b, an inter-unit pipe composed of a gas pipe 5 and a liquid pipe 7 extends, and outdoor units 1a, 1b are connected in parallel to this inter-unit pipe.

The oil separator 12a includes a compressor 11a
To separate the lubricating oil in the refrigerant discharged from the
The lubricating oil separated here is always returned to the compressor 11a through the oil return pipe 21a and the forced oil return pipe 22a. A capillary tube 24a is always provided in the oil return pipe 21a, and a flow path resistance is applied to oil returned to the compressor 11a by the capillary tube 24a. This constant oil return pipe 21a is connected in the middle of the oil separator 12a, and as long as the oil level of the oil in the oil separator 12a is higher than the position where the oil return pipe 21a is connected, the oil is constantly supplied to the compressor 11a through the constant oil return pipe 21a. It is returned to the suction pipe. On-off valves 23a and 25a are provided in the forced oil return pipe 22a.
The forced oil return pipe 22a is connected to the oil separator 12
The oil in the oil separator 12a is forcibly returned to the suction pipe of the compressor 11a by opening the on-off valves 23a and 25a.

The forced oil return pipes 22a and 22b of the outdoor units 1a and 1b are connected by a balance pipe 51. The balance pipe 51 is connected between the four-way valve 13a and the check valve 18a through a third auxiliary pipe 53a, and the third auxiliary pipe 53a is provided with a third on-off valve 55a.

The third on-off valve 55a opens, and the four-way valve 13a
Is switched to the illustrated position, the balance pipe 51 communicates with the outdoor heat exchanger 14a.

In this air conditioner, each outdoor unit 1
The oil amount in each of the outdoor units 1a and 1b is measured, and when the oil amount in one of the outdoor units 1a and 1b is insufficient, the oil is collected from the other outdoor units 1a and 1b and the oil amount between the outdoor units 1a and 1b is measured. Control for balancing is performed.

In the conventional configuration, an oil level sensor for measuring the amount of oil is attached to the compressor. Therefore, when the compressor has large vibration, for example, in a compressor driven by a gas engine, this vibration greatly affects the compressor. As a result, the durability of the oil level sensor decreases, and the oil amount cannot be accurately detected.

In this embodiment, as shown in FIG. 2, the oil separators 12a and 12b, which are not affected by vibrations, are provided with oil level sensors Sa and Sb composed of float switches.
Are respectively attached.

According to this, each compressor 1 is not affected by the vibration of the gas engine 11b and the like as follows.
The oil amounts of 1a and 11b can be estimated, and the durability of the oil level sensors Sa and Sb is improved. The oil level sensor S
Since a and Sb have the same configuration, only one oil level sensor Sa will be described below, and the description of the other oil level sensor Sb will be omitted.

In FIG. 2, the compressor 11a is driven by a gas engine 11b. 11c and 11d are pulleys, and 11e is a V-belt.

The above-mentioned constant oil return pipe 21a is connected to the L level (second level) at a distance A from the bottom of the oil separator 12a, and the actual oil level LL in the oil separator 12a becomes higher than this L level. In some cases, the oil in the oil separator 12a is theoretically always returned to the compressor 11a via the capillary tube 24a.

The oil level sensor Sa is connected to the oil introduction pipe 10
1 and the degassing pipe 102, the oil level L in the oil separator 12a is connected to the oil separator 12a.
· The same oil level L as L can be detected.

The degassing pipe 102 has a screen 103
Or, it is connected below the cup 104. If the connection is made above the screen 103 or beside the cup 104, an internal pressure difference occurs between the oil introduction pipe 101 and the gas release pipe 102, and the oil level sensor malfunctions.

In this embodiment, as described above, when the actual oil level LL in the oil separator 12a is higher than the L level (second level), the oil separator 12
The oil in a is theoretically always returned to the compressor 11a.

However, when the oil level falls below the L level, the constant return of the oil is immediately stopped. Therefore, in this embodiment, the oil separator 1
When the oil level LL in 2a is equal to or lower than the M level (first level) higher than the L level, it is estimated that the oil amount of the outdoor unit 1a is "insufficient".

When the M level exceeds the M level and the H level is reached, it is estimated that the oil amount of the outdoor unit 1a is "sufficient" to such an extent that the oil can be supplied to the other outdoor unit 1b. The reason why the "insufficient" estimated level is set to the M level is that the safety against running out of oil is considered in comparison with the L level as described above.

The oil level sensor Sa outputs an oil sufficiency signal when it is estimated that the outdoor unit 1a is "satisfied" with oil, and outputs an oil sufficiency signal when it is estimated that the oil is "sufficient". Is output.

In the system according to this embodiment, the oil in the oil separators 12a and 12b is constantly compensated to the level M or higher. That is, the oil level sensors Sa and Sb
If the level is lower than the level, an oil shortage signal is output. If the level is lower than the M level, oil recovery control from another outdoor unit is executed. In this case, oil is collected from the other outdoor unit to the compressor of the own outdoor unit, so that the oil accumulates in the own oil separator through the compressor, thereby compensating for the M level.

Therefore, the oil return pipes 21a, 21b are always
The oil is always returned to the compressor through the compressor, so that there is no shortage of oil.

When the compressor is started, when the rotation speed of the compressor is unstable, or when the amount of oil in the oil separator is equal to or less than L level (second level) lower than M level, forced oil is applied. The oil in the own oil separator is returned to the own compressor through the return pipes 22a and 22b.

By the combination control of the constant oil return control and the forced oil return control, the oil in the compressor is always secured.

Next, the oil recovery control will be described with reference to the flow chart of FIG. First, at the start (S1), when the cooling operation is being performed (S2), the compressor 11
It is determined whether there is a shortage in the amount of oil in a (a) (S
3). This determination is made based on a signal from the oil level sensor Sa.

If the determination in S3 is NO, there is no oil shortage, and the cooling control is continued without change. If YES, the outdoor unit 1b having a sufficient oil amount is Check if there is (S
4). S4 is confirmed based on a signal from the oil level sensor Sb.

Here, if there is an outdoor unit having a sufficient amount of oil, control for recovering oil from the outdoor unit is executed (S5). For example, when the oil amount of one outdoor unit 1a is insufficient and the oil is collected from the other outdoor unit 1b, the open / close valve 23a of the one outdoor unit 1a is closed, and the open / close valve (oil recovery valve) 2
Open 5a. Further, the open / close valve (balance valve) 23b of the other outdoor unit 1b is opened, the oil recovery valve 25b is closed, and the third open / close valve (flushing valve) 55b is opened. Then, both outdoor units 1a and 1b are operated. Then
Oil separator 12 in the other outdoor unit 1b
b, as indicated by the dotted arrow, the balance valve 2
3b, balance tube 51, and one outdoor unit 1
The oil is recovered in the suction pipe of the compressor 11a via the oil recovery valve 25a in a. Thereby, each outdoor unit 1a,
The oil amount between 1b is balanced.

If there is no outdoor unit having a sufficient amount of oil in S4, there is no longer any recoverable oil, so that the operating capacity of the outdoor unit with insufficient oil is reduced (S6). If the outdoor unit is provided with a rated compressor, the operation of the outdoor unit is stopped. If the outdoor unit is provided with a compressor equipped with an inverter, the frequency is reduced and the rotational speed of the compressor is reduced.

When the above-mentioned oil amount balance control (S5) is completed, a so-called high-pressure refrigerant flushing control of the bypass pipe is executed (S7). In this case, the flushing valve 55b in the other outdoor unit 1b is opened. When this is opened, the pressure of the high-pressure refrigerant causes the balance pipe 51 to open.
The oil inside is flushed vigorously toward one outdoor unit 1a. The control in S7 is executed for about 10 seconds, and when this time-out occurs (S8), the process proceeds to the cooling control in S2. In FIG. 3, the flow shows the flow at the time of cooling, but the process at the time of heating is the same.

According to this, through the balance tube 51,
After adjusting the oil amount by flowing the oil from the larger oil amount to the smaller oil amount, the high-pressure refrigerant is introduced into the balance pipe 51,
The oil remaining in the balance pipe 51 is sent out to the return pipe 21a of the compressor 11a by the high-pressure refrigerant, so that the oil does not remain in the balance pipe 51 after adjusting the oil amount. Therefore, the durability of the on-off valve (solenoid valve) is improved, and it does not malfunction or liquid sealing occurs. Further, since the flushing control of the bypass pipe 51 by the high-pressure refrigerant is performed, even if the distance between the outdoor units is long, that is, even if the length of the bypass pipe 51 is long, the lubricating oil does not remain, and The adverse effect can be surely eliminated.

[0038]

According to the present invention, since the sensor is attached to the oil separator, the sensor is not affected by vibration.
The oil amount can be detected. Therefore, the durability of the sensor is improved, and the oil amount can be accurately detected.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an example of an air conditioner according to the present invention.

FIG. 2 is a refrigerant circuit diagram near an oil separator.

FIG. 3 is a flowchart illustrating a process according to an embodiment.

[Explanation of symbols]

 1a, 1b Outdoor unit 3 Indoor unit 5 Gas pipe 7 Liquid pipe 10a, 10b Accumulator 11a, 11b Compressor 12a, 12b Oil separator 14a, 14b Outdoor heat exchanger 21a, 21b Return pipe 23a, 23b Open / close valve 25a, 25b Open / close valve Sa, Sb sensor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuo Kumehara, 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Akira Shindo 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Ryota Hirata 2-5-5 Keihanhondori 2-chome, Moriguchi-shi, Osaka Prefecture (72) Inventor Yoshihiro Nakamura 2 Keihanhondori, Moriguchi-shi, Osaka 5-5-5 Sanyo Electric Co., Ltd. (72) Inventor Takami Higashi 2-5-5 Sanyo Electric Co., Ltd., Sanyo Electric Co., Ltd. (72) Inventor Junji Matsue Keihan Moriguchi, Osaka 2-5-5 Hondori Sanyo Electric Co., Ltd. (72) Koji Nagae 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 3L060 AA01 CC08 CC19 DD01 EE 01 EE04

Claims (4)

[Claims] 1. An outdoor unit comprising: an outdoor heat exchanger, a compressor, and an oil separator; and a plurality of outdoor units for returning oil separated by the oil separator to the compressor via a return pipe. Are connected in parallel to the piping between the units extending from the indoor units, and the oil amount in each outdoor unit is measured. If the oil amount in any one of the outdoor units is insufficient, the oil is collected from the other outdoor units and each outdoor unit is collected. An air conditioner provided with a means for balancing an oil amount between the two, wherein a sensor for measuring an oil amount in the outdoor unit is provided in the oil separator. 2. An outdoor unit comprising: an outdoor heat exchanger, a compressor, and an oil separator; and a plurality of outdoor units for returning oil separated by the oil separator to the compressor via a return pipe. Are connected in parallel to the piping between the units extending from the indoor units, and the oil amount in each outdoor unit is measured. If the oil amount in any one of the outdoor units is insufficient, the oil is collected from the other outdoor units and each outdoor unit is collected. In the air conditioner provided with a means for balancing the amount of oil between the oil separator and the compressor, a constant level oil return pipe connects the oil separator and the compressor. A sensor for detecting the oil level in the oil separator is provided in the oil separator, and the sensor detects oil in the oil separator. If the oil level is detected to be less than the oil level of the first level, it is estimated that the oil amount in the outdoor unit is insufficient and oil is collected from another outdoor unit. Air conditioner. 3. An outdoor unit including an outdoor heat exchanger, a compressor, and an oil separator, and a plurality of outdoor units for returning oil separated by the oil separator to the compressor via a return pipe. Are connected in parallel to the piping between the units extending from the indoor units, and the oil amount in each outdoor unit is measured. If the oil amount in any one of the outdoor units is insufficient, the oil is collected from the other outdoor units and each outdoor unit is collected. In the air conditioner provided with means for balancing the oil amount between the oil separator and the compressor, the forced oil return pipe and the constant oil return pipe connect the oil separator and the compressor, and the constant oil return pipe enables oil return. A sensor for detecting the oil level in the first level oil separator is provided on the oil separator, and the sensor When the amount of oil in the separator is detected to be equal to or less than the oil level of the first level, it is estimated that the amount of oil in the outdoor unit is insufficient, and the oil is collected from another outdoor unit. When the compressor is started, when the rotation speed of the compressor is unstable, or when the amount of oil in the oil separator is equal to or less than the second level oil level lower than the first level oil level, forced oil return is performed. An air conditioner characterized by returning oil in its own oil separator to a compressor through a pipe. 4. The air conditioner according to claim 2, wherein the sensor is an oil level sensor that can detect an oil level in an oil separator that can always return oil with an oil return pipe.