JPH0791750A - Freezer device - Google Patents

Abstract

PURPOSE:To provide a freezer in which the overheat of coolant at a start of operation is prevented, while keeping a proper temperature constantly, by a method wherein the coolant undergoes forced cooling, rather than automatically controlled, for a given period of time in the beginning. CONSTITUTION:When a freezer operating signal is generated, a coil 15 of a time-limiting relay is electrically energized and a b-contact 14 of the time limit relay is kept closed for a specified period of time. As a result, a coil 18 of an auxiliary relay is also electrically energized only for a set time of the time limit relay, a b-contact 16 of the auxiliary relay is opened and the a-contact is closed. With such an arrangement as above, only a main solenoid valve 5 is opened, cooling is carried out during the set time of the time limit relay with the refrigerant liquid and an automatic control of the coolant temperature with the temperature switch is not carried out. In turn, upon elapsing of the set time, the b-contact 14 of the time limit relay is opened and the coil 18 of the auxiliary relay is not magnetized, resulting in that the temperature after this operation is automatically controlled under operation of the temperature switches 11 and 12, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle for air conditioners and refrigerators.

[0002]

2. Description of the Related Art A conventional device is a frozen VOL. 63, No.
As described on page 50 of the September 731 issue of 1988, a refrigerator equipped with a water-cooled oil cooler is the mainstream.

[0003]

In the prior art, the water-cooled oil cooler regularly checks the water quality and cleans the inner surface of the cooling pipe in order to prevent the heat exchange efficiency from being deteriorated due to the dirt on the water side. It has the drawback of requiring maintenance.

Further, the oil amount can be controlled by adjusting the cooling water amount or the cooling water inlet water temperature, but it cannot be followed when the oil temperature rises in a short time such as when the refrigerator is started, and in some cases, the oil temperature The protection device for preventing an excessive rise may operate and the refrigerator may become inoperable, and no consideration has been given to an increase in the oil temperature at the start of the refrigerator.

An object of the present invention is to prevent the occurrence of a high oil temperature refueling state at the time of starting in a refrigerator equipped with a refrigerant cooling type oil cooler capable of simplifying or eliminating water side maintenance, and To secure a good oil temperature.

[0006]

In order to achieve the above object, the present invention relates to an oil cooling main solenoid valve and an oil cooling main expansion valve connected in a pipe between a receiver and an oil cooler, and an oil. By connecting the auxiliary solenoid valve for cooling and the auxiliary expansion valve for oil cooling that are connected in parallel, the automatic temperature control of the oil temperature by the temperature controller is not performed for the period from the start of the compressor until the fixed time elapses. , Forcibly open the oil cooling main solenoid valve.

[0007]

In the case of the refrigerant cooling type oil cooler, the temperature of the refrigerating machine oil, which is the object to be cooled, can be adjusted by controlling the flow rate of the liquid refrigerant that is the cooling body after passing through the oil cooling expansion valve. Since the plurality of oil-cooling expansion valves have different cooling capacities, it is possible to change the flow rate of the liquid refrigerant and to control the oil temperature stepwise by combining them. For these controls, the oil cooling solenoid valve is automatically opened and closed by the operation signals of the two oil supply temperature switches that sense the oil temperature.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the refrigeration cycle system diagram of FIG. The refrigerant of the compressor 1 is compressed into high temperature and high pressure gas. This refrigerant gas becomes a condensed liquid in the condenser 2 and accumulates in the liquid receiver 3. Of this refrigerant liquid, the main flow liquid is supplied to the evaporator 4 via the main expansion valve 13 which is a pressure reducing mechanism, where the object to be cooled is cooled and then sucked into the compressor 1.

On the other hand, a part of the refrigerant liquid in the liquid receiver 3 is supplied to the refrigerant cooling type oil cooler 7 through the electromagnetic valves 5 and 9 and the expansion valves 6 and 10 which are pressure reducing mechanisms to cool the oil. After that, it is guided to the intermediate pressure section of the compressor 1. Further, the oil cooled by the refrigerant cooling type oil cooler 7 is supplied to the bearing portion of the compressor 1 after foreign matters are removed by the oil strainer 8.

A main solenoid valve 5 and a main expansion valve 6 and a sub solenoid valve 9 and a sub expansion valve 10 are connected in parallel between the liquid receiver 3 and the refrigerant cooling type oil cooler 7. Further, the temperature-sensing parts of the oil supply temperature switches 11 and 12 for automatically controlling the oil temperature detect the oil temperature between the refrigerant cooling type oil cooler 7 and the compressor 1 to perform control.

The capacity of the main expansion valve 6 is larger than that of the auxiliary expansion valve 10, and the oil cooling effect is also large.

FIG. 2 shows a control circuit diagram of the present invention.

The coil 15 of the time delay relay is energized by the refrigerator operation signal, and the b contact 14 of the time delay relay is kept closed for a certain time until the set time elapses. Therefore, the coil 18 of the auxiliary relay is also energized only for the set time of the time delay relay, the b contact 16 of the auxiliary relay is opened, and the a contact of the auxiliary relay is closed.

As a result, only the main solenoid valve 5 is opened, and only the main solenoid valve cools the oil for the set time of the time delay relay, and the automatic control of the oil temperature by the oil supply temperature switch is not executed.

After the elapse of the set time, the b contact 14 of the time delay relay
Is opened and the coil 18 of the auxiliary relay is demagnetized, so that the oil temperature control thereafter is switched to automatic control by the operation of the oil supply temperature switches 11 and 12. Lubrication temperature switch 11,
The operating values of 12 are 11, 12
And the relationship.

FIG. 3 shows the capacity state of the expansion valve with respect to the oil supply temperature.

The relation of the oil supply temperature is in the order of t ₁ <t ₂ <t ₃ <t _{4 and} the higher the oil supply temperature, the larger the heat exchange amount of the expansion valve is required.

After the set time of the time delay relay, the b contact 16 of the auxiliary relay in FIG. 2 is closed and the oil supply temperature switch 11 is off, so that the auxiliary expansion valve 10 is used until the oil supply temperature t ₂ is reached. Oil temperature control is performed.

When the oil supply temperature reaches t ₂ , the oil supply temperature switch 11 is turned on and the oil temperature control of only the main expansion valve 6 is switched. Further, when the oil supply temperature further rises and reaches t ₃ ,
The oil supply temperature switch 12 is turned on, and the oil temperature control using both the main expansion valve 6 and the auxiliary expansion valve 10 is performed.

The oil supply temperature t ₃ is the operating temperature of the protective device when the oil supply temperature rises abnormally, and the refrigerator is stopped.

As described above, in addition to the forced oil temperature control for a fixed time from the start of the refrigerator, the automatic oil temperature control for each expansion valve alone and the automatic oil temperature control for simultaneous use of these expansion valves are three-step control. However, it is possible with a minimum of parts.

The diagram (a) in FIG. 4 shows the oil temperature change characteristic when the main expansion valve 6 is not subjected to the forced oil temperature control immediately after the start of the refrigerator. On the other hand, the diagram (b) shows the oil temperature change characteristics when the oil supply temperature is suppressed by forcibly opening the main expansion valve 6, which has a large cooling effect only for a certain time after the refrigerator is started. Show.

[0023]

According to the present invention, after the refrigerator is started,
For a certain period of time until the sub-expansion valve for the oil cooler can supply a stable liquid refrigerant, the flow of the oil-cooling liquid refrigerant is compensated by the action of the main expansion valve to suppress a rapid temperature rise immediately after the start. Is possible.

Further, stable lubrication of the bearing of the compressor is
It is possible to prevent poor lubrication of the bearing and suppress the shortening of the service life.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle system diagram showing an embodiment of the present invention.

FIG. 2 is a control circuit diagram.

FIG. 3 is a capacity diagram of the expansion valve when the oil supply temperature rises, and an explanatory diagram showing the relationship between the oil supply temperature and the heat exchange amount of the expansion valve.

FIG. 4 is an oil temperature change characteristic diagram of elapsed time from starting of the refrigerator and oil supply temperature.

[Explanation of symbols]

1 ... Compressor, 2 ... Condenser, 3 ... Liquid receiver, 4 ... Evaporator, 5
... Main solenoid valve for oil cooler, 6 ... Main expansion valve for oil cooler, 7 ...
Refrigerant cooling type oil cooler, 8 ... Oil strainer, 9 ... Oil cooler auxiliary solenoid valve, 10 ... Oil cooler auxiliary expansion valve, 11, 12 ...
Lubrication temperature switch, 13 ... Main expansion valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Minor Kasezawa 390 Muramatsu, Shimizu City, Shizuoka Prefecture, Shimizu Plant, Hitachi, Ltd. (72) Yoshifumi Suzuki Yoshifumi Suzuki, 390 Muramatsu, Shimizu City, Hitachi Hitachi Shimizu Engineering Co., Ltd. Within

Claims (1)

[Claims] 1. A refrigeration cycle by connecting a compressor, a condenser, an evaporator, a liquid receiver, a plurality of oil cooling solenoid valves, a plurality of oil cooling expansion valves and a refrigerant cooling type oil cooler by piping. In a refrigerator that controls the oil temperature by controlling the opening and closing of the oil cooling solenoid valve with a temperature controller, the oil cooling is not automatically controlled for a certain period immediately after the start of the refrigerator, but the oil cooling is forced. Refrigeration cycle, which is characterized by being carried out.