JPH0354374Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a hermetic centrifugal refrigerator, and particularly to a cooling device for a main motor thereof.

(Prior Art) Conventionally, as a cooling device for the main motor of a hermetic centrifugal chiller, the one shown in Fig. 3 is known (see pages 74-75 of "Centrifugal chillers and their handling" published by the Japan Refrigeration Association). ). A cooling passage 6 is provided from the lowest part of the condenser 3 to the main motor 2 via the evaporator 4, and a cooling pump 6a is provided in the cooling passage 6 between the condenser 3 and the evaporator 4. It is. Under normal conditions, the condensate is supplied to the main motor 2 using the differential pressure between the condensation pressure and the evaporation pressure to cool the coil and the like.
In addition, under conditions such as winter when the cooling water temperature is low and the condensing pressure is low, a sufficient differential pressure with the evaporation pressure cannot be obtained and the amount of condensate supplied is insufficient, so the cooling pump 6a is operated to condense. It makes up for the lack of fluid. In the figure, numeral 1 is a compressor, and 5 is a main circuit.

There are also systems that change the condensing pressure itself without using a cooling pump to ensure the required amount of differential pressure with the evaporation pressure. That is, in this case, the amount of cooling water in the condenser is controlled so that the necessary condensation pressure can be ensured even when the temperature of the cooling water is low.

(Problems to be solved by the invention) As mentioned above, in the case where the cooling pump 6a is used to compensate for the lack of condensing pressure, the structure is complicated because the cooling pump 6a and accompanying piping members are required. easy to change. Furthermore, failure of the cooling pump 6a may cause serious accidents such as burning out of the coil of the main motor 2 or seizure of its bearings, resulting in a lack of reliability.

On the other hand, controlling the amount of cooling water to compensate for the lack of condensing pressure wastes power and is disadvantageous in terms of energy conservation.

(Purpose of the invention) This invention was made in view of the above points, and the purpose is to ensure that the necessary amount of condensate for cooling the traction motor can be obtained with a simpler structure. .

(Means for solving the problem) By the way, in order to feed the condensate from the condenser 3 to the main motor 2, the head difference between the two
The size of Ph and the differential pressure Pa between the condenser 3 and the evaporator 4 determines whether or not feeding is possible and whether the amount is excessive or insufficient. In other words, if the head difference Ph and the differential pressure Pa do not satisfy the relational expression Ph < Pa, a sufficient amount of condensate cannot be delivered, and conventionally, by increasing this differential pressure Pa, the above relational expression is satisfied. I was letting it happen.

The present invention focuses on the head difference Ph, and by making it possible to reduce this, even when the differential pressure Pa decreases due to a drop in temperature, etc., the amount of condensed liquid required to cool the main motor 2 is This is to ensure that a sufficient amount of

Specifically, as shown in FIG. 1, a cooling liquid storage chamber 8 is partitioned by disposing a partition wall 7 that collects the condensed liquid at the highest possible position of the refrigerant chamber 3a of the condenser 3, and this liquid The cooling passage 6 is led out from the storage chamber 8 so that the head difference Ph with respect to the main motor 2 can be made small.

(Function) As a result, in the present invention, since the cooling passage 6 is led out from a high position in the condenser 3, the lead-out height is higher than in the conventional case where the cooling passage 6 is led out from the lowest part of the condenser 3. The head difference Ph can be reduced by an amount corresponding to the difference in position. Therefore, even in winter when the differential pressure Pa between the condensing pressure and the evaporation pressure is small, a sufficient amount of cooling condensate can be supplied to the main motor 2.

(Embodiment) FIG. 1 shows a first embodiment of this invention.
In FIG. 1, the hermetic centrifugal refrigerator is constructed by integrating a turbo-type compressor 1 and a main motor 2 that rotationally drives the compressor, and refrigerant gas compressed under pressure by the compressor 1 is condensed and liquefied in a condenser 3. The refrigerant that has been vaporized and gasified in the evaporator 4 is sent to the compressor 1 again.
circulate to. 5 is the main circuit for that purpose.

A cooling passage 6 is provided between the condenser 3 and the main motor 2 in order to cool mainly the coils of the main motor 2 using the condensed liquid. In addition, at the highest possible position of the refrigerant chamber 3a in the condenser 3,
A horizontal partition wall 7 is provided protruding from the inner wall to define a cooling liquid storage chamber 8, and the cooling passage 6 is led out from the inner bottom of the liquid storage chamber 8. Although not shown, the partition wall 7 is attached to a structure within the refrigerant chamber 3a, such as a partition plate of a water box or a space between adjacent cooling pipes. In order to obtain the feed pressure, a part of the cooling passage 6 is passed through the evaporator 4,
A low pressure section 9 is formed here.

The cooling condensate supplied to the main motor 2 through the cooling passage 6 is sprayed into the case from the end bell of the main motor 2, cools the rotor and stator coils, etc., and then is led out from the inner bottom of the case. It is returned to the evaporator 4 via the reflux passage 10.

By configuring the cooling passage 6 as described above, the head difference Ph between the cooling liquid storage chamber 8 and the main motor 2 can be reduced, so the differential pressure between the condensing pressure and the evaporation pressure can be reduced.
Even when Pa is small, a sufficient amount of cooling condensate can be reliably delivered.

(Another Embodiment) FIG. 2 shows another embodiment. In this case,
This embodiment differs from the above embodiment in that the supply amount of cooling condensate can be adjusted. That is, a bypass passage 12 is branched from the cooling passage 6 between the cooling liquid storage chamber 8 and the evaporator 4, and this is connected to the liquid passage 5a connecting the condenser 3 and the evaporator 4, and this bypass Electromagnetic valves 13 and 14 are interposed at two locations, one in the middle of the passage 12 and the other between the bypass passage 12 branch of the cooling passage 6 and the evaporator 4, respectively. Both electromagnetic valves 13 and 14 are controlled to open and close according to detection signals from a temperature sensor (not shown) attached to the main motor 2 that detects the coil temperature. When the amount is large, excessive cooling condensate is prevented from being fed to the main motor 2, thereby eliminating power consumption loss.

In the embodiment described in FIG. 2, the two solenoid valves 13 and 14 are used to adjust or limit the flow rate, but this is not necessarily necessary; for example, the flow rate may be controlled using one throttle valve. You can also do it like this.

(Effect of the invention) As explained above, in this invention, the condenser 3
The outlet portion of the cooling passage 6 is set to the cooling liquid storage chamber 8 provided at a high position, and the head difference Ph necessary for supplying the cooling condensate to the main motor 2 is set.
is made small, so even if the cooling water temperature in the condenser 3 is low and a high condensation pressure cannot be obtained, the necessary and sufficient amount of condensate to cool the traction motor 2 can be reliably supplied to the traction motor 2. can do. In addition, since the condensate can be fed using only the differential pressure between the condensing pressure and the evaporation pressure without using a dedicated cooling pump, the cooling structure can be simplified. Moreover, since there is no functional component such as a cooling pump, there is no need to worry about its failure, and it is advantageous in that high reliability can be obtained. Furthermore, compared to a system in which the amount of cooling water in the condenser 3 is controlled to obtain the condensing pressure necessary to feed the cooling condensate, there is no waste in power consumption and it is advantageous in terms of energy conservation. .

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a centrifugal refrigerator showing a first embodiment of the present invention. FIG. 2 is a conceptual diagram equivalent to FIG. 1 showing a second embodiment of the present invention. FIG. 3 is a conceptual diagram of a conventional turbo chiller. 1... Compressor, 2... Main electric motor, 3... Condenser, 4... Evaporator, 6... Cooling passage, 8... Cooling liquid storage chamber, Ph... Head difference.

Claims (1)

[Scope of utility model registration request] The cooling passage 6 is led out from the condenser 3, passes through the evaporator 4, and reaches the main motor 2, and the condensed liquid for cooling is passed through the cooling passage 6 by the differential pressure Pa between the condensing pressure and the evaporation pressure. In a hermetic turbo chiller, the refrigerant is supplied to the main motor 2 via the refrigerant chamber 3 of the condenser 3.
A cooling liquid reservoir chamber 8 for receiving the condensed liquid is defined at the highest possible position of a, and the cooling passage 6 is connected from this liquid reservoir chamber 8 to the cooling passage 6.
A hermetic centrifugal chiller characterized by being derived from.