JPS60118037A - Cooler of motor in refrigerator - Google Patents

Abstract

PURPOSE:To reduce the frictional loss when cooling a motor with coolant by not filling the coolant in a space for containing a rotor of the motor and maintaining the space at a low pressure. CONSTITUTION:Coolant is evaporated by heat generated from a stator 7 in a sealed space 10A to become coolant vapor. The stator 7 and the periphery are cooled by the evaporating latent heat when the coolant is evaporated. The coolant vapor in the space 10A is fed from an outlet 12 through an exhaust passage 14 to an evaporator 5 or the suction side of a compressor 2. Thus, since the coolant is introduced only into the periphery of the stator but not introduced to a housing 6 which contains a rotor 9, the pressure in the housing 6 is maintained lower than the space 10A, and the frictional loss when the rotor 9 is rotated can be reduced in the amount corresponding to the lower pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a motor cooling device for a refrigerator such as a centrifugal refrigerator or a screw refrigerator.

[Background of the invention]

As disclosed in Japanese Patent Application Laid-Open No. 9-11911, a conventional method for cooling a motor is to sprinkle a refrigerant liquid on the rotor and stator of the motor without separating them, and cool them using the latent heat of vaporization. As a result, the rotor rotates at high speed under high pressure and gas-liquid coexistence, resulting in large friction losses.Also, because the refrigerant used for cooling was taken from the condenser and returned to the evaporator, the electric motor was moved during the refrigeration cycle. There is a problem in that the work required for cooling is included, and the efficiency of the refrigerator as a whole is reduced.

[Purpose of the invention]

An object of the present invention is to reduce friction loss when cooling an electric motor in a refrigerator with a refrigerant liquid.

[Summary of the invention]

The main cause of friction loss is that the rotor rotates at high speed under high pressure and in the coexistence of gas and liquid, while the stationary stator section accounts for most of the heat generated to be cooled. Therefore,
In order to cool only the stator with a refrigerant liquid, the present invention provides a partition wall surrounding the stator, and introduces a cooling refrigerant liquid into the sealed space formed by the partition wall.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1, 2, 3 and 4 show an embodiment of the present invention. FIGS. 1 and 2 show a first embodiment of the present invention. A turbo refrigerator is driven by an electric motor 1 and includes a turbo or screw compressor 2 that boosts the pressure of refrigerant vapor. The refrigerant vapor pressurized by the turbo compressor 2 flows into the condenser 3, where it is cooled and liquefied by cooling water passing through the pipe 3A. The liquefied refrigerant liquid is depressurized via the decompression mechanism 4, and then flows into the evaporator 5. In this evaporator 5, the refrigerant liquid takes heat from the water flowing in the pipe 5A and evaporates, becoming refrigerant vapor, which is sucked into the compressor 2, compressed again, and repeats this process.

When the refrigerant liquid evaporates in the evaporator 5, heat is removed from the water in the tube 5A, cooling the water in the tube 5A and producing cold water. Although the above-mentioned refrigerator has been explained using the most basic refrigeration cycle as an example, it can be applied to a refrigeration cycle that has been modified, such as one equipped with an economizer.

Next, the cooling structure of the electric motor will be explained with reference to FIG. Partition wall 1 attached to housing 6 so as to surround stator 7
0, an inlet 11 formed in the housing 6. Outlet 12
It consists of The refrigerant liquid region of the condenser 3 and the inlet IJ are connected through an introduction passage 13 for cooling refrigerant liquid, and the outlet 12 and the evaporator 5 are connected through an exhaust passage 14 for refrigerant vapor after cooling. ing.

Further, in the middle of the introduction passage 13, there is a valve 13A for adjusting the amount of refrigerant liquid passing therethrough and reducing the pressure. As this valve 13A, a valve of a type that adjusts the flow rate of the cooling refrigerant liquid depending on the temperature of the stator 7 of the electric motor 1 can be used.

Next, the operation will be explained.

The refrigerant liquid passes through the introduction passage 13 and flows from the inlet 11 into the closed space 10A formed by the partition wall 10. The refrigerant liquid is vaporized in this closed space 10A by the heat generated from the stator 7, and becomes refrigerant vapor. The stator 7 and its surroundings are cooled by latent heat of vaporization when the refrigerant liquid vaporizes.

Refrigerant vapor in the closed space 10A flows from the outlet 12 through the discharge passage 14 to the evaporator 5 or the suction side of the compressor 2. As mentioned above, since the cooling refrigerant liquid is introduced only around the stator and the cooling refrigerant is not introduced into the housing 6 housing the rotor 9, the pressure inside the housing 6 is lower than that in the closed space 10A. The friction loss when the rotor 9 rotates is reduced by the lower pressure.

Furthermore, since the stator 9 is the main component that generates heat in the electric motor, and this portion is cooled, sufficient cooling can be achieved. FIG. 3 shows a second embodiment of the present invention, in which a pump 15 for reducing pressure is provided in the middle of the introduction passage 13, and the outlet of the discharge passage 14 is connected to the condenser 3.

In this embodiment, a cooling refrigerant liquid is pumped into the closed space 10A by a pump 15, and the refrigerant vapor is returned to the condenser 3 after cooling the stator 7.

According to this embodiment, the amount of heat released from the electric motor can be released to the outside of the refrigerator via the refrigerant and the cooling water of the condenser 3, so that the amount of heat released from the electric motor is equivalent to the amount of heat required to cool the electric motor compared to the first example. The cooling capacity increases accordingly.

FIG. 4 shows a third embodiment of the present invention, in which a cooling coil 16 is provided in the middle of the discharge passage 14, and this cooling coil 16 is placed below the pipe of the condenser 3 or in the refrigerant liquid. It is something. In this way, the surrounding refrigerant liquid or the refrigerant liquid condensed in the upper tube falls and sprinkles on the cooling coil 16, thereby cooling the cooling coil 16. Therefore, the refrigerant vapor passing through the cooling coil 16 is liquefied in the cooling coil 16, and at the same time, the pressure is also lowered.

Due to the difference between the pressure at the cooling coil 16 and the pressure inside the condenser 3, the refrigerant liquid flows through the introduction passage 16 into the closed space 10A, and the cooling refrigerant flows from the condenser 3 to the introduction passage 13 to
Inflow hole 11 → closed space 10A → outflow hole 12 → discharge passage 1
3→cooling coil 16→discharge passage 13→evaporator 5.

According to this embodiment, as in the second embodiment, the heat taken from the electric motor can be released to the outside of the refrigerator, and
The cooling refrigerant liquid can be circulated without using a pump, and a pump for pressure-feeding the refrigerant liquid and a power source for the pump become unnecessary.

Note that the cooling coil 16 may be disposed within the cooling water header of the condenser 3, or may be disposed within an independent shell, and the cooling water may be circulated within the shell.

〔Effect of the invention〕

As described above, according to the present invention, the space in which the rotor of the electric motor is housed is not filled with refrigerant liquid, the space is maintained at a low pressure, and the refrigerant liquid does not collide with the rotating rotor. Friction loss can be significantly reduced. This has the effect of improving the efficiency of the refrigerator.

[Brief explanation of drawings]

1 to 4 are detailed explanatory diagrams of the present invention, in which FIG. 1 is a system diagram of the first embodiment, FIG. 2 is an explanatory diagram of main parts of the first embodiment, and FIG. The system diagram of the second embodiment, FIG.
It is a system diagram of an example of. 1... Electric motor, 2... Compressor, 3... Condenser, 4
... Pressure reduction mechanism, 5 ... Evaporator, 6 ... Housing, 7 ... Stator, 8 ... Shaft, 9 ... Rotor, 1
0... Partition wall, IOA... Sealed space, 11... Inflow port, 12... Outlet port, 13... Introduction passage, 14...
- Discharge passage, 15...pump, 16...cooling coil. No.

Claims (1)

[Claims] 1. An evaporator that produces cold water by evaporating refrigerant liquid, a compressor that boosts the pressure of the refrigerant vapor evaporated by this evaporator, an electric motor that drives this compressor, and an electric motor that boosts the pressure of the refrigerant vapor that has been boosted by the compressor. In a turbo chiller equipped with a condenser that cools and liquefies the liquid and a decompression mechanism that reduces the pressure of the condensed refrigerant before it reaches the evaporator, it has a partition that surrounds the stator of the electric motor, and is formed by this partition. 1. A cooling device for an electric motor in a centrifugal chiller, comprising a passage for introducing refrigerant liquid of the centrifugal chiller and a passage for discharging refrigerant vapor in a sealed space. 2. In claim 1, the path for discharging the refrigerant vapor in the closed space is connected to a cooling pipe arranged in the condenser, and when the refrigerant vapor in the closed space passes through this cooling pipe, A cooling system for an electric motor in a refrigerator, which is liquefied into liquid and then flows into an evaporator.