JPH07103580A - Cooling device for canned motor for refrigerator - Google Patents

Abstract

PURPOSE:To prevent the lowering of cooling efficiency caused by changes in the condition (pressure) of a refrigerator by forming a separate lubricating apparatus for special use in cooling a canned motor for the purpose of cooling the canned motor used in a compressor for refrigerating application. CONSTITUTION:A lubricating circuit consisting of a canned motor 2, a transmitting joint chamber 4 and an exterior pipe 6 is filled with the refrigerating machine oil used in an open type refrigerator 1, the oil is circulated by a circulating pump 3 housed in the canned motor 2 connected to a rotor and the lube oil is cooled by a cooling coil 5 provided in the transmitting joint chamber 4 to cool the canned motor 2. An equalization pipe is provided with a check valve for escaping to the refrigerator 1 the oil, etc., leaking from the mechanical seal of the refrigerator 1 for separating the lubricating circuit and the refrigerator 1 and is disposed between a refrigerator oil chamber and the lubricating circuit, whereby the air sealing performance of the mechanical seal is stabilized.

Description

Detailed Description of the Invention

[0001]

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

[0002]

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

[0003]

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

The mechanical seal installed on the drive unit side of the open type refrigerator has its airtightness ensured by supplying pressurized lubricating oil to the seal sliding surface. The supplied lubricating oil leaks to the lubricating circuit of the canned motor, so the internal pressure of the lubricating circuit rises and the lubricating oil on the motor side flows back from the mechanical seal to the refrigerator side while the refrigerator is stopped and is sealed in the motor. There is a risk of running out of lubricating oil. Therefore, it is necessary to return the lubricating oil from the motor side to the refrigerator side so that the pressure inside the motor and the sealed amount are constant.

To cool the lubricating oil, it is necessary to use cooling water or liquid refrigerant for cooling, but in the system in which the lubricating oil flows inside the pipe, the circulation pump power becomes large due to the friction loss of the lubricating oil. In order to reduce such reactive power, a cooling method that does not affect the friction loss of lubricating oil is required.

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

[0007]

To achieve the above object, a canned motor cooling device for a refrigerator of the present invention comprises a transmission coupling chamber between a canned motor having a built-in circulation pump used in a refrigerator and the refrigerator. A canned motor, a transmission joint chamber, and a lubricating circuit configured by an external pipe are provided to enclose refrigerating machine oil used in a refrigerator, and the lubricating oil is circulated by a circulation pump coupled to the rotor shaft of the canned motor, Lubricating oil is cooled by a cooling coil installed in the transmission joint chamber for feeding cooling water or liquid refrigerant to cool the canned motor.

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

Further, the external pipe is connected to the suction side of a circulation pump built in the canned motor from the transmission joint chamber, and is cooled from the outer surface through an outer pipe for feeding cooling water or liquid refrigerant to the outside. Provide a heavy pipe type lubricating oil cooling unit.

[0010]

According to the present invention, the oil filled in the lubricating circuit constituted by the canned motor, the transmission joint chamber and the external pipe is directly connected to the motor rotor at the same time as the operation of the refrigerator by the canned motor. The oil sent out by the circulation pump flows into the transmission joint chamber while lubricating the bearing and cooling between the rotor and the can. In the transmission joint chamber, the cooling oil cools the lubricating oil, and the external piping supplies oil to the circulation pump again and circulates it as shown by the arrow in FIG.

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

Further, the pressure inside the motor and the amount of the lubricating oil filled are kept substantially constant, the airtightness of the mechanical seal of the refrigerator is not deteriorated, and the pressure change of the refrigerator causes a change 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 dual-pipe type lubricating oil cooling section for cooling from the outer surface by an external pipe is used together, friction loss of the lubricating system is not increased, so that it is effective in a motor having a large output.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the device of the present invention will be illustratively described in detail below 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 only to them, unless otherwise specified, and are merely described. Only.

FIG. 1 is a sectional view of a canned motor cooling device directly connected to an open type refrigerator, and FIG. 2 is a partially enlarged sectional view thereof. In FIGS. 1 and 2, 1 is a canned motor 2.
The open type refrigerator 3 driven by the is a circulation pump built into the canned motor, and the oil sent out by the blades 3a of the circulation pump 3 directly connected to the rotor of the motor lubricates the bearings and the can and the rotor. While flowing between the refrigerator 1 and the canned motor 2, it 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 joint chamber 4 through its chamber wall, and the lubricating oil is cooled by the cooling coil 5 in the transmission joint chamber 4, and the canned motor 2 is removed from the transmission joint chamber 4. Of the circulation pump 3 again by the external pipe 6 arranged so as to be sucked on the suction side of the circulation pump 3.
Is refueled. The external pipe 6 is provided with a double pipe type lubricating oil cooling section 7 which is an auxiliary for supplying cooling water or liquid refrigerant to the external pipe. Reference numeral 8 is a pressure equalizing pipe outlet with the refrigerator.

By simply forming the independent lubrication circuit on the motor side, as shown in FIG.
Since a small amount of oil leaks from the unit, the pressure of the independent lubrication circuit rises and the airtightness of the mechanical seal 11 deteriorates. As described above, a pressure equalizing pipe is used as a circuit for returning oil from the motor side to the refrigerator 1. 9 is provided, and a check valve 10 that flows only from the motor side to the refrigerator side is provided in the piping circuit. Reference numeral 12 is a gear type shaft coupling that connects the motor shaft of the canned motor and the drive shaft of the refrigerator 1.

FIG. 3 is a diagram showing a construction 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 joint chamber 4 is checked from the pressure equalizing pipe 9 by a check valve. Return to the refrigerator side chamber via 10. Further, the check valve 10 prevents backflow from the refrigerator side.

[0019]

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

[Brief description of drawings]

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

FIG. 2 is an enlarged cross-sectional view showing a relationship with a mechanical seal portion of a refrigerator.

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

[Explanation of symbols]

 1 Open Type Refrigerator 2 Canned Motor 3 Circulation Pump 3a Blades 4 Transmission Joint Chamber 5 Cooling Coil 6 External Piping 7 Double Pipe Lubricating Oil Cooling Section 8 Pressure Equalizing Pipe Outlet 9 Equalizing Pipe 10 Check Valve 11 Mechanical Seal 12 Gear Shaped shaft coupling

Claims (2)

[Claims] 1. A transmission joint chamber between a refrigerator and a canned motor, and a lubrication circuit composed of a canned motor, a transmission joint chamber, and external piping are provided to seal refrigerating machine oil used in the refrigerator, and this lubrication is performed. The oil is circulated by a built-in circulation pump that is connected to the rotor, the lubricating oil is cooled by a coil cooling pipe installed in the transmission joint chamber, and the oil leaked from the mechanical seal of the refrigerator that separates the lubricating circuit from the refrigerator. A canned motor cooling device for a refrigerator, in which a pressure equalizing pipe having a check valve for releasing the above to the refrigerator is installed between the refrigerator and the lubrication circuit. 2. The external pipe is a double pipe type lubricating oil cooling section which is connected to a circulation pump built in the canned motor from the transmission joint chamber and which is passed through an outer pipe for feeding cooling water or liquid refrigerant. A canned motor cooling device for a refrigerator as described.