JPH0645810Y2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a refrigeration system of a type in which a single compressor supplies refrigerant to a plurality of evaporators.

[Conventional technology]

In air conditioners for automobiles, offices, or room coolers for homes, which have a relatively large passenger compartment volume, the gas-phase refrigerant compressed by one compressor is cooled and liquefied by a condenser, and the flow paths of electromagnetic valves are switched. A refrigerating apparatus of the type used by appropriately distributing and supplying the plurality of evaporators via the means is used.

The refrigerant that has lost the latent heat of vaporization from the air to be conditioned in the evaporator and returned to the gas phase is connected to the respective refrigerant outlets when there are two evaporators as shown in FIG. After following the return pipe b1 or b2, which has reached the T-shaped merging point A and merging, it flows into the refrigerant suction pipe c and is sucked into the compressor connected to the end thereof.

[Problems to be solved by the invention]

In the refrigerating apparatus of the type in which the refrigerant is supplied to a plurality of evaporators by one compressor as described above, it has been experienced that the rotation of the compressor is often disordered during operation.

The inventor of the present application conducted a series of experiments for investigating the cause of the occurrence of such a disorder, and found the following facts.

That is, a part of the lubricating oil for the compressor stored in the compressor casing is mixed in the refrigerant that continues to flow in the circulation pipe connecting the respective components of the refrigeration cycle and is circulated together with the refrigerant. The mixed state is compatible in the liquid-phase refrigerant, and is uniformly mixed in the high-pressure gas-phase refrigerant from the compressor to the pressure reducing device on the upstream side of the evaporator in a mist state to form a refrigerant vapor. With it, it flows at almost the same speed. On the other hand, in the low-pressure gas-phase refrigerant on the downstream side of the decompression device, it is separated from the refrigerant and is adhered to the inner wall surface of the pipe due to its inherent viscosity, and is pushed by the flow of the gas-phase refrigerant and is slower than this flow. Is sent to the downstream side.

Then, as shown in FIG. 8, in the conventional refrigerating apparatus having the T-shaped confluence point A, when the refrigerant is supplied to both of the two evaporators, the two refrigerating units are pushed toward the T-shaped confluence point A from the opposite direction. Lubricating oil (c), which is transferred along the inner wall surface of the pipe while being pushed by the incoming two-system refrigerant gas flows (a) and (b), is smoothly flowed down into c of the suction pipe.

However, when the refrigerant supply to one evaporator is stopped, as shown in FIG. 9, the refrigerant gas flow (a) flowing from one return pipe b1 toward the confluence A. Is blown into the other return pipe b2 where there is no gas flow due to inertia, and at this time, the lubricating oil (c) is also entrained and part of it is pushed into the pipe b2. Once piping b2
The lubricating oil that has entered the inside adheres to its inner wall surface due to its viscosity and gradually accumulates (d), but since there is no pushing back force to the merging point A, the lubricating oil mixed in the refrigerant and flowing in the circulation pipe Of these, the rate of returning to the compressor will decrease over time.

According to the actual measurement of the refrigeration cycle for cooling mounted on the wagon, when the refrigerant is supplied to only one of the two evaporators, the circulation rate of the lubricating oil is lower than that when the refrigerant is supplied to the two evaporators at the same time. It was confirmed to be reduced by about 20%.

On the other hand, when investigating a tilting piston pump type compressor that failed in rotation during operation, the contact part between the swash plate and the shoe was worn, and in extreme cases, the piston was broken and the compressor was obviously damaged. It was inferred that the circulation supply of lubricating oil to the machine was hindered.

In order to prevent such poor circulation of lubricating oil,
No. 754 proposes a refrigeration system in which an oil return device is installed upstream of the confluence, but it has drawbacks such as an increase in the number of parts, an increase in assembly man-hours, and an installation space.

The purpose of this invention is to prevent the lubricating oil from accumulating in the refrigerant return pipe on the idle side with a simple structure when one of the evaporators is shut down, and to prevent rotational malfunction of the compressor during operation. It is to provide a refrigerant device capable of removing the main cause.

[Means for solving problems]

In order to achieve the above object, the refrigerating apparatus according to the present invention supplies a refrigerant to a plurality of evaporators by one compressor, and joins a return pipe of the refrigerant connected to each outlet of the plurality of evaporators to one place. After that, the shape of the confluent manifold is devised in the refrigerating apparatus which is connected to the suction port of the compressor via the refrigerant suction pipe and which can suspend the supply of the refrigerant to the specific evaporator.

That is, the confluence manifold of the present invention has at least its end portion,
A plurality of branch pipe portions having a drain portion that tilts downward and a confluent pipe portion that is connected immediately after the lower ends of the drain portions and extends further downward than the drain portion are provided.

Here, "immediately after the lower end" of the drain part, which is the connecting position of the merging pipe part in the present invention, means the state of being directly connected to the lower end or being connected to a position near the lower end.

Further, in the present invention, the return pipes of the plurality of evaporators are respectively connected to the upper ends of the plurality of branch pipe portions, and the confluent pipe portion is connected to the refrigerant suction pipe.

[Effect of action and device]

In the refrigerating apparatus of the present invention having the above-described configuration, the lubricating oil returns well even when the refrigerant is supplied to only one of the plurality of evaporators, for example, one of the two evaporators. Done. That is, as described above, in the vicinity of the confluence point of the refrigerant return pipes of the two evaporators, a part of the lubricating oil for compressor mixed in the refrigerant flowing in the return pipe of one evaporator is accompanied by the flow of the refrigerant gas. Attempting to penetrate into the return pipe of the other evaporator, both return pipes are connected to the upper ends of the branch pipe parts of the confluence manifold, and the plural branch pipe parts are connected to the ends of the branch pipe parts. Since the drain pipes are inclined downward and the merging pipes are connected downward immediately after the lower ends of these drain parts, the lubricating oil receives gravity more than pressing force by the refrigerant gas flow, Without falling into the return pipe of the evaporator, it falls in the direction connected to the suction port of the compressor and is sucked into the compressor.

Therefore, the circulating oil for the compressor, which mixes with the refrigerant in the refrigerant circulation pipe of the refrigeration cycle and circulates together, is prevented from staying in the middle of the pipe line as described above, which is the main cause of the rotational malfunction of the compressor. Are removed.

Moreover, since the merging pipe portion of the merging manifold is configured to be directly connected to the lower end of the plurality of drain portions inclined downward, that is, directly connected to the lower end or a position in the vicinity of the lower end, a plurality of, for example, 2 Even when the refrigerant is supplied to only one of the basic evaporators, the lubricating oil that tries to enter the drain part of the branch pipe part connected to the evaporator that does not supply the refrigerant immediately gravitationally moves to the end part of the merging pipe part. And is sucked into the compressor through the confluent pipe section.

Further, in the present invention, if a plurality of branch pipes connected to the return pipes of the plurality of evaporators are provided with a downwardly inclined drain portion, any one of the plurality of evaporators is in a refrigerant supply stopped state. Even if it does, without retaining the oil on the evaporator side that is in the stopped state,
The oil can be returned to the compressor.

Further, in the present invention, since the confluence points of a plurality of return pipes are configured by the original confluence manifold of the present invention described above, an oil return device is not required, and the number of parts, the number of assembling steps and the mounting space are increased. It is possible to reliably prevent stagnation of lubricating oil with a simple structure without causing expansion.

〔Example〕

The configuration of the present invention will be specifically described below based on the embodiments shown in the accompanying drawings.

FIG. 1 to FIG. 4 are diagrams showing an embodiment of a refrigeration unit of an automobile air conditioner mounted on a wagon vehicle.

In the suction port 1b of the only compressor 1 mounted,
The vaporized refrigerant that has been sucked in after completing the refrigeration work is compressed into a high temperature and high pressure state, and then sent out from the discharge port 1a into the high pressure side refrigerant delivery pipe a. Then, the first and second condensers 3 and 4 which are connected in series are liquefied by being sequentially passed, and branched into two via a receiver 5 as a temporary storage tank for the liquid-phase refrigerant. The high-pressure side refrigerant pipes a1 and a2 are separately supplied. The refrigerant that has traced each of the two pipes is supplied to the first evaporator 2A and the second evaporator 2B that are dispersedly arranged in the front portion and the rear portion of the vehicle interior.

The high pressure side refrigerant pipes a1 and a2 from the receiver 5 to the first and second evaporators are respectively provided with a solenoid valve 6 or 7 for supplying and disconnecting the refrigerant and a pressure reducing device 8 or 9 for decompressing and atomizing the liquid phase refrigerant. There is.

Return pipes b1 or b2 as low-pressure side refrigerant pipes are connected to the refrigerant outlets of the first evaporator 2A for cooling the front passenger compartment and the second evaporator 2B for cooling the rear passenger compartment, respectively. The terminal slanted portions d1 and d2 of the pipe form a branch pipe portion having a slanted portion that is linearly slanted downward. The inclined portion constitutes a drain portion for discharging liquid such as lubricating oil, and a merging pipe portion to which the upstream end of the refrigerant suction pipe C is connected is formed immediately after the lower end of the inclined portion. As is clear from FIG. 3, “immediately after the lower end of the inclined portion forming the drain portion” refers to a position near the lower end in this example.

The compressor 1 is intermittently driven by a torque of a vehicle engine transmitted through a magnet clutch 15 that is turned on and off based on control information sent from a control circuit 13 of an air conditioner, and a pulley 16 that is connected to the clutch. Driven to. The solenoid valves 6 and 7 are opened and closed by the movement of the exciting coil 6a or 7a whose energization is turned on and off by the control circuit 13. Reference numeral 14 is a vehicle-mounted battery power source, 11 and 12 are fans for blowing air to be conditioned on the first or second evaporator 2A or 2B, respectively, and 17 is a forced cooling fan for the first condenser 3. Two condens 3
And 14 are installed at a place D where the air outside the vehicle can be introduced.

As shown in FIG. 2 as a perspective view of the wagon vehicle, the first evaporator 2A is installed in an air conditioning duct (not shown) as a main body part of the air conditioner installed below the driver's seat instrument panel. Has been paid. The second evaporator
2B is housed in a casing 20 of a cooling unit mounted on the ceiling of the vehicle compartment so as to face the rear vehicle compartment. Reference numerals 21, 22, and 23 denote a blower, an air intake port, and a cold air blowout port of this cooling unit, respectively.

Next, the operation of the apparatus of the above embodiment will be described. When the power switch is turned on by the operation panel of the air conditioner, the control circuit 13
Is operated, and the two solenoid valves 6 and 7 are appropriately opened and closed so as to maintain an arbitrary preset air-conditioning temperature based on the information from the vehicle interior temperature sensor.
When the set temperature is reached, the magnet clutch 15 is turned off.

When both solenoid valves 6 and 7 are open, the refrigerant is supplied to the two evaporators 2A and 2B at the same time. The refrigerants that have performed the refrigeration work and are discharged to the respective return pipes b1 and b2 reach the merging point A and merge, then flow into the suction pipe C and are sucked into the compressor 1. In the merging pipe section 10A and the branch pipe sections 10B and 10C in the merging manifold 10 near the merging point A, regardless of whether or not the end sloping sections d1 and d2 of the return piping b1 and b2 are inclined, the refrigerant is present in this vicinity. It is impossible for the mixed lubricating oil of (1) to stay for the reasons described above.

When only one of the solenoid valves 6 and 7 is opened by the operation of the control circuit 13 or by a manual device, the confluence manifold 10 where the branch pipe portions 10B and 10C of the two refrigerant return pipes b1 and b2 join together. As seen in FIG. 4 as a side sectional view of the confluence point A, the branch pipe portion 10B of one of the return pipes (b1 in this case) was traced by the suction force of the compressor 1 and reached the confluence point A. Most of the refrigerant gas (a) flows into the suction pipe C, but a part thereof enters into the branch pipe portion 10C of the other return pipe b2 where there is no refrigerant gas flow due to inertia as described above, and On the occasion, carry lubricating oil (C).

However, since the end slanted portions d1 and d2 of the pipes b1 and b2 are both slanted downward toward the confluence point, the vector of the refrigerant gas flow is superior in the downward direction component to the horizontal direction component, and the refrigerant gas is The degree of invasion into the branch pipe portion 10C of the pipe b2 can be considerably reduced. Moreover, the lubricating oil (c) that once entered the branch pipe portion 10C of the other pipe b2 along with the gas flow also flows down toward the inlet end of the refrigerant suction pipe C along the inclination of the terminal inclined portion d2. As a result, the inclined portion d2 acts as a drain portion. Therefore, unlike the conventional device, the reduction in which the lubricating oil gradually accumulates in the branch pipe portion 10C of the other pipe b2 cannot occur.

Therefore, it is possible to avoid a serious inconvenience that the circulation amount of the lubricating oil to the compressor 1 gradually decreases when the one-side operation state in which the refrigerant is supplied to only one of the two evaporators 2A and 2B is continued.

FIG. 5 is a side cross-sectional view showing a second embodiment of the pipe in the confluence manifold 10 at the confluence point A of the refrigerant return pipe, showing the branch pipe portions 10B and 10C of the two return pipes b1 and b2 and the refrigerant. The merging pipe portion 10A of the suction pipe C is joined in a Y shape. 30 is a block-shaped pipe joint for collecting pipes. Therefore, in this example, "immediately after the lower end of the inclined portion forming the drain portion" means a state of being directly connected to the lower end.

FIG. 6 shows a merging manifold 10 at a merging point A as a third embodiment.
FIG. 2 is a side sectional view showing the piping structure of the two return pipes.
The branch pipe portions 10B and 10C of b1 and b2 are connected in a U shape. Therefore, while the drain portion is formed as the linear inclined portions d1 and d2 in the embodiment shown in FIG. 3 described above, it is bent in a curved shape in the third embodiment shown in FIG.

Further, although the return pipes b1 and b2 are two in the first embodiment, the branch pipe portion which is the end of the third refrigerant return pipe is connected in the middle of the branch pipe portion 10C of the refrigerant return pipe b2. Therefore, three evaporators may be incorporated. And
The merging point of the third return pipe plays the same role as the merging point A of the return pipe described above. Furthermore, it is also possible to freely connect the fourth refrigerant return pipe to the branch pipe portion 10B of the pipe b1.

FIG. 7 is an inclined view of the merging manifold 10 at the merging point A of the fourth embodiment, showing the respective terminal inclined parts d1 and d2 of the three refrigerant return pipes.
The branch pipe portions 10B, 10C, and 10D of d3 and d3 are gathered in a V shape and are connected to the merging pipe portion 10A of the suction transfer pipe C. When two or more evaporators are incorporated, a part of them can be used for cooling and the rest can be used for refrigerator or freezer.

It should be noted that the three inclined end portions of the refrigerant return pipe do not necessarily have to be gathered at the same portion. Further, the suction pipe C does not necessarily need to be attached vertically downward, and may be connected by inclining downward from the confluence point of the return pipe depending on the installation space of the device.

In all of the refrigerant return pipes b1, b2 ... In the above-mentioned embodiment, all of the terminal inclined portions d1, d2 ... Are inclined downward, but the refrigerant is continuously flowed without providing a refrigerant supply suspension means. The refrigerant return pipe of the existing evaporator (an evaporator other than the specific evaporator) does not need to be inclined downward near the confluence point A.

[Brief description of drawings]

1 to 4 show the first embodiment, FIG. 1 is a refrigerating cycle diagram, and FIG. 2 is an arrangement of a refrigerating device of a wagon vehicle in which the refrigerating cycle of FIG. 1 is incorporated in an air conditioner. A perspective view showing the situation, and FIGS. 3 and 4 are a side view and a side cross-sectional view showing a confluent portion of the refrigerant return pipe. FIG. 5 to FIG. 7 are second to sixth examples, respectively, showing the piping structure of the confluent portion of the refrigerant return piping as a side sectional view. FIG. 8 and FIG. 9 are side cross-sectional views showing the flow of the lubricating oil mixed in the refrigerant at the confluence point of the refrigerant return pipe of the conventional refrigeration system. In the figure, 1 ... Compressor, 2A, 2B ... Evaporator,
3, 4 ... Capacitor, 6, 7 ... Solenoid valve, 8, 9 ...
Pressure reducing device, b1, b2 ... Refrigerant return piping, C ... Refrigerant suction piping, d1, d2 ... Refrigerant return piping end inclined portion, A ...
Confluence point, 10 ... Confluence manifold, 10A ... Confluence pipe section, 10B,
10C, 10D ... Branch section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeo Numazawa 1-1, Showa-cho, Kariya city, Aichi Prefecture Nihon Denso Co., Ltd. (72) Inventor Tetsuo Itasaka 1-1-chome, Showa town, Kariya city, Aichi prefecture Co., Ltd. (72) Inventor Hiroshi Koyama 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd. (72) Inventor, Akio Ogiso 1-1, Showa-cho, Kariya city, Aichi Nihondenso Co., Ltd. (56) Bibliographic Reference Showa 58-177754 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A refrigerant is supplied to a plurality of evaporators by one compressor, and a return pipe of the refrigerant connected to each outlet of the plurality of evaporators is joined at one location, and then, a refrigerant suction pipe is used. A refrigeration apparatus capable of stopping the supply of the refrigerant to the specific evaporator while being connected to the suction port of the compressor, and a plurality of branch pipe portions having a drain portion inclined downward at least at an end thereof and the drain portions. Is connected immediately after the lower end of
A converging manifold consisting of a converging pipe portion extending further below the drain portion is provided, and return pipes of the plurality of evaporators are connected to upper ends of the plurality of branch pipe portions, respectively, and the confluent pipe portion is used for the refrigerant suction. Refrigeration equipment connected to piping.