JP2572535B2 - Canned motor cooling device for refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cooling of a canned motor used in a refrigerating compressor, and more particularly to an apparatus for using an open type refrigerating machine as a closed motor type refrigerating machine.

[0002]

2. Description of the Related Art Conventionally, in a canned motor for a refrigerator, a seal of the refrigerator has been abolished and a part of lubricating oil of a lubrication system of the refrigerator has been directly used for cooling the motor.

[0003]

The lubrication system of the refrigerator receives a change in the pressure on the evaporator side, and the amount of the lubricating oil decreases due to the oil forming by the refrigerant gas contained in the lubricating oil due to the rapid decrease in the pressure. In addition, there is a risk of insufficient cooling of the canned motor and poor lubrication of the refrigerator bearing. Therefore, it is necessary to provide a lubrication system that is not affected by the refrigerator on the canned motor, to eliminate fluctuations in the amount of lubricating oil, and to stabilize cooling of the canned motor.

[0004] The mechanical seal installed on the drive device side of the open type refrigerator is ensured for airtightness by supplying pressurized lubricating oil to the seal sliding surface. Since the supplied lubricating oil leaks into the lubrication circuit of the canned motor, the internal pressure of the lubrication circuit increases, and the lubricating oil on the motor side flows back from the mechanical seal to the refrigerator while the refrigerator is stopped, and is sealed in the motor. There is a risk of running out of lubricating oil. For this reason, it is necessary to return the lubricating oil from the motor side to the refrigerator side so that the pressure and the filling amount inside the motor are constant.

[0005] Cooling of lubricating oil requires cooling using cooling water or liquid refrigerant. However, in a system in which lubricating oil flows inside the piping, the power of the circulating pump increases due to friction loss of the lubricating oil. In order to reduce such reactive power, a cooling system that does not affect the friction loss of the lubricating oil is required.

The present invention relates to an improvement of a cooling device for a canned motor used in a refrigerating compressor, which comprises an independent lubrication system (circuit) dedicated to cooling a canned motor, and a reduction in cooling efficiency due to a pressure change on the refrigerator side. The purpose is to prevent the problem.

[0007]

To achieve the above object, a canned motor cooling device for a refrigerator according to the present invention comprises a transmission joint chamber between a canned motor with a built-in circulation pump used for the refrigerator and the refrigerator; A canned motor, a transmission coupling chamber, a lubricating circuit composed of external piping is provided, and refrigerating machine oil used in the refrigerator is sealed, and the lubricating oil is circulated by a circulation pump coupled to a rotor shaft of the canned motor, The lubricating oil is cooled by a cooling coil installed in the transmission joint chamber for supplying cooling water or liquid refrigerant, thereby cooling the canned motor.

A pressure equalizing pipe having a check valve for releasing oil or the like leaking from a mechanical seal of the refrigerator separating the lubrication circuit and the refrigerator from the refrigerator is installed between the refrigerator and the lubrication circuit. By doing so, the airtightness of the mechanical seal is stabilized.

Further, the above-mentioned external piping is connected to the suction side of a circulating pump built in the canned motor from the transmission joint chamber and is connected to the outside pipe for cooling from the outside through an external pipe for supplying cooling water or liquid refrigerant outside. A double-tube lubricating oil cooling unit is provided.

[0010]

According to the present invention, the oil sealed in the lubrication circuit composed of the canned motor, the transmission joint chamber and the external piping is directly connected to the motor rotor simultaneously with the operation of the refrigerator by the canned motor. The oil sent out by the circulation pump flows to the transmission joint chamber while lubricating the bearing and cooling between the rotor and the can. In the transmission joint chamber, the lubricating oil is cooled by the cooling coil, supplied to the circulation pump again by the external piping, and circulated as shown by the arrow in FIG.

The oil leaking from the mechanical seal of the open type refrigerator not only raises the pressure of the lubrication circuit of the canned motor but also acts on the mechanical seal to lower the sealing performance. A pressure equalizing pipe equipped with a check valve that flows from the motor to the refrigerator only from the motor side is provided.Oil leaking into the transmission joint chamber is cooled by the cooling coil and when the internal pressure increases, the reverse Since the lubricating oil is returned to the refrigerator oil chamber through the stop valve, the lubricating oil is not subjected to oil forming due to a change in pressure of the refrigerator.

Further, the pressure inside the motor and the amount of lubricating oil charged therein can be kept substantially constant, so that the hermetic performance of the mechanical seal of the refrigerator does not decrease, and changes in the pressure of the refrigerator can occur in the lubricating oil circuit of the motor. The independence of the lubrication circuit that does not appear can be secured.

Further, even if a double-pipe lubricating oil cooling unit for cooling from the outer surface with an external pipe is used in combination, it is effective for a motor having a large output because friction loss of a lubricating system is not increased.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the present invention thereto, unless otherwise specified. Only.

FIG. 1 is a cross-sectional view of a canned motor cooling device directly connected to an open type refrigerator, and FIG. 2 is a partially enlarged cross-sectional view thereof. In FIGS.
The open-type refrigerator 3 is a circulating pump built in the canned motor, and the oil sent out by the blades 3a of the circulating pump 3 directly connected to the rotor of the motor lubricates the bearings and cancels the oil with the rotor. While cooling between the two, the air flows into the transmission joint chamber 4 installed between the refrigerator 1 and the canned motor 2.

A cooling coil 5 is installed inside the transmission coupling chamber 4 through the wall of the transmission coupling chamber 4. In the transmission coupling chamber 4, the lubricating oil is cooled by the cooling coil 5, and the canned motor 2 is transferred from the transmission coupling chamber 4 to the transmission coupling chamber 4. Of the circulation pump 3 by the external piping 6 arranged to be sucked to the suction side of the circulation pump 3
Refueled. The external pipe 6 is provided with a double-tube lubricating oil cooling unit 7 which is an auxiliary for supplying cooling water or liquid refrigerant to the external pipe. Reference numeral 8 denotes an outlet of a pressure equalizing pipe with the refrigerator.

By simply forming the independent lubrication circuit on the motor side, as shown in FIG.
From the motor, the pressure of the independent lubricating circuit increases, and the airtightness of the mechanical seal 11 decreases. As described above, the pressure equalizing pipe serves as a circuit for returning oil from the motor side to the refrigerator 1. In the piping circuit, a check valve 10 that flows only from the motor side to the refrigerator side is provided. Reference numeral 12 denotes a gear type shaft coupling for connecting the motor shaft of the canned motor and the drive shaft of the refrigerator 1.

FIG. 3 shows a configuration diagram in which the transmission joint chamber and the oil chamber of the refrigerator are connected by a pressure equalizing pipe 9. Oil leaking into the transmission coupling chamber 4 receives a check valve from the pressure equalizing pipe 9. After 10, return to the refrigerator side chamber. The check valve 10 prevents backflow from the refrigerator.

[0019]

According to the present invention employing the above structure, not only can the open type refrigerator be used as a closed type refrigerator, but also the above-mentioned problems can be solved, and the oil due to pressure fluctuation of the refrigerator can be solved. It has become possible to prevent the cooling efficiency of the canned motor or the like from being reduced due to the forming.

[Brief description of the drawings]

FIG. 1 is a sectional view of a canned motor cooling device for a refrigerator according to the present invention.

FIG. 2 is an enlarged sectional view showing a relation with a mechanical seal portion of the refrigerator.

FIG. 3 is a configuration diagram of a pressure equalizing pipe in the apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 open-type refrigerator 2 canned motor 3 circulation pump 3 a blade 4 transmission coupling chamber 5 cooling coil 6 external piping 7 double-pipe lubricating oil cooling section 8 equalizing pipe outlet 9 equalizing pipe 10 check valve 11 mechanical seal 12 gear Shaft coupling

Claims (2)

(57) [Claims] A lubricating circuit comprising a transmission coupling chamber, a canned motor, a transmission coupling chamber, and external piping is provided between a refrigerator and a canned motor, and refrigerating machine oil used in the refrigerator is sealed therein. Oil is circulated by a built-in circulating pump connected to the rotor, lubricating oil is cooled by a coil cooling pipe installed in the transmission joint chamber, and oil leaks from the mechanical seal of the refrigerator that separates the lubrication circuit and the refrigerator. A canned motor cooling device for a refrigerator, in which a pressure equalizing pipe having a check valve that allows the air to escape to the refrigerator is installed between the refrigerator and the lubrication circuit. 2. A double-pipe lubricating oil cooling section connected to a circulating pump built into the canned motor from the transmission joint chamber and passing through an outer pipe for supplying cooling water or liquid refrigerant. The canned motor cooling device for a refrigerator according to the above.