JP2001173598A - Liquid refrigerant pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the motor of a closed liquid refrigerant pump for an ice thermal storage type air conditioning system. SOLUTION: The pump part 11 of the closed liquid refrigerant pump 1 and the motor part 12 thereof are separated from each other by pressure, and also a returning piping 6 returned from an interior heat exchanger 8 to an ice thermal storage tank 2 is connected to the motor part 12 so that the whole evaporated refrigerant gas is passed through the motor 12, thus the exothermic action of the motor is absorbed and the efficiency and reliability thereof can be secured. A sufficient amount of refrigerant gas is supplied so that abnormal heating can be prevented, and liquid refrigerant may not be brought into contact with a motor winding so that there is no fear of a current leakage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump for supplying pressurized refrigerant cooled and liquefied by heat exchange with stored ice in an ice storage type air conditioning system. The present invention relates to a structure of a liquid refrigerant pump incorporating a motor suitable for realizing the above.

[0002]

2. Description of the Related Art For the purpose of leveling power consumption and conserving energy in the summer, ice is stored inside an ice heat storage tank by using nighttime electric power, and ice is stored in the daytime. The ice storage type air conditioning system is becoming practical. As disclosed in Japanese Patent Laid-Open Publication No. Hei 6-241582, in an ice storage type air-conditioning system, a refrigerant in a liquefied state is used as a means for sending a refrigerant rather than circulating a gaseous refrigerant in a compressor. It is more efficient to pump the refrigerant with a liquid pump. In addition, in the refrigerant cycle, all members through which the refrigerant passes, such as pipes, valves, heat exchangers, and pumps, should be sealed so that there is no ingress or egress of the outside air, in order to avoid dissipation of the refrigerant and ingress of moisture in the atmosphere. This is a preferable structure, and increases the reliability of the machine.

However, in the conventional liquid refrigerant pump, up to the motor is integrated with the pump, and the hermetically sealed type housed in the chamber is not common, and a pump having a rotary shaft seal driven by an external motor or a canned motor is used. Most were driven. These driving methods have disadvantages such as an increase in the size of the structure, leakage of the refrigerant from a shaft seal, etc., and a decrease in the motor efficiency, and the problem remains as a liquid refrigerant pump.

[0004]

In the above-mentioned prior art, the structure of the liquid refrigerant pump is not described, and it is not known how to realize the liquid refrigerant pump as a highly reliable sealed type.

A fluid compressor having a structure similar to that of a closed liquid refrigerant pump is a closed compressor, which is widely used in the field of refrigeration and air conditioning. However, in the compressor, the refrigerant is in a gas phase during the entire process from suction to discharge, whereas in the liquid refrigerant pump, the refrigerant is in a liquid phase. This difference is a major structural difference in cooling the motor. The motor generates heat due to its own energy loss,
If the cooling is insufficient, the temperature becomes high, and failures such as winding insulation breakdown occur. Since the hermetic compressor has a structure in which the motor is disposed in the flow of the refrigerant gas because the refrigerant is in a gaseous phase, the motor can be cooled by the refrigerant.

However, when the refrigerant is in a liquid state, this method cannot be used for the following reasons. First, in an ice storage type refrigerant cycle, the degree of supercooling of the liquid refrigerant is small, and the refrigerant is easily vaporized by heat exchange with the motor.
The vaporization of the refrigerant inside the pump greatly expands the volume, so that a positive displacement pump that sends a constant volume per unit time reduces the supply mass, which is not preferable. Secondly, slight impurities such as water contained in the liquid refrigerant cause the refrigerant to have lower electrical insulation than in a gaseous state, and may cause a short circuit or short circuit in a motor winding or power supply wiring. Third, when a rotating part such as the rotor of the motor rotates in the liquid, the viscosity of the liquid is much higher than that of the gas, so that the stirring loss increases and the efficiency decreases. For the above reasons, there is a problem that the same method as that of the conventional hermetic compressor cannot be used for cooling the motor in the hermetic liquid refrigerant pump integrated with the motor.

The present invention has been made in view of the above-mentioned disadvantages of the related art, and has as its object to realize a sealed and highly reliable liquid refrigerant pump by reliably performing cooling of a motor unit. Another object of the present invention is to provide an efficient ice storage air conditioning system using the pump.

[0008]

To achieve the above object, the following first means is used.

A liquid refrigerant pump according to the present invention includes a pump section in which a pump body in a common chamber serving as a pressure vessel is housed;
It consists of a motor section in which a motor for driving the pump body is housed. The pump section and the motor section are pressure-isolated to prevent inadvertent flow of fluid even if a pressure difference occurs. Therefore, the power shaft for transmitting the rotating power generated by the motor unit to the pump unit is provided with a means for transmitting power and isolating pressure, such as a shaft seal.

A main flow path of the liquid refrigerant to be pressurized and supplied by the pump section is formed inside the chamber of the liquid refrigerant pump. In order to communicate this with the outside, at least two communication paths penetrating through the chamber wall are provided. , Respectively, as an inlet and an outlet of the liquid refrigerant. Further, the motor unit also has at least two communication passages that penetrate the wall of the chamber and communicate the outside and the space in the chamber, and serve as an inlet and an outlet for the refrigerant gas.

When the liquid refrigerant pump according to the above means is used in an ice storage type air conditioning system, the performance of the liquid refrigerant pump is fully utilized and high reliability is ensured by configuring the piping system as follows. Can be. In the ice storage type air conditioning system, the refrigerant circulates and air-conditions in an annular refrigerant pipe passing through the ice heat storage tank and the indoor heat exchanger. The liquid refrigerant pump according to the above means is provided in the middle of a refrigerant pipe on the outward path from the ice heat storage tank to the indoor heat exchanger on the refrigerant cycle. A pipe from the heat storage tank is connected to a liquid refrigerant inlet of the liquid refrigerant pump, and a pipe to an indoor heat exchanger is connected to an outlet of the liquid refrigerant pump. Further, in the middle of the refrigerant pipe returning from the indoor heat exchanger to the ice heat storage tank and returning, the pipe from the indoor heat exchanger to the refrigerant gas inlet provided in the motor part of the same liquid refrigerant pump, and the ice heat storage to the refrigerant gas outlet. The piping to the tank is connected to form a piping system through which the refrigerant gas passes through the motor unit.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, using FIG. 1 and FIG.
A configuration and operation of a liquid refrigerant pump according to a first embodiment of the present invention and an ice storage type air conditioning system using the same will be described. FIG. 1 is a schematic diagram of a piping system of the ice storage air conditioning system according to the present embodiment. FIG. 2 is a schematic sectional view of the structure of the liquid refrigerant pump used in the air conditioning system of FIG.

The ice regenerative air conditioning system shown in FIG. 1 extracts only a refrigerant system operating during indoor cooling with stored ice. Therefore, the heat exchangers and compressors installed outdoors that operate during heat storage ice making or heating operation, and piping and valves related to them are omitted.

First, the piping system will be described according to the flow path of the refrigerant. In-tank heat exchanger 3 provided in ice thermal storage tank 2
Is connected to the liquid inlet 21 of the liquid refrigerant pump 1 and the liquid outlet 25 is connected to the indoor heat exchanger 8 with the outward pipe 5. An expansion valve 10 is provided on the outward pipe 5 immediately upstream of the indoor heat exchanger 8. The indoor heat exchanger 8 has a means for blowing indoor air by a fan 9. The return pipe 6 extends downstream of the indoor heat exchanger 8 and is connected to the gas inlet 28 of the liquid refrigerant pump.
Connect to Further, the return pipe 7 extends from the gas outlet 29 communicating with the gas inlet 28 in the motor section, returns to the in-tank heat exchanger 3, and forms a circulation flow path.

The position of the ice heat storage tank 2 is set higher than the liquid refrigerant pump 1 and is filled with a heat storage agent which is water or an aqueous solution. Except for the heat exchanger, the pipes are covered with heat insulating material to prevent heat exchange with the surrounding outside air.

The liquid refrigerant pump 1 shown in FIG. 2 is entirely covered with a chamber 13 which is a pressure-resistant container, and the inside thereof can be roughly divided into a pump section 11 and a motor section 12. The pump section 11 is composed of a pump main body 20 having a capability of supplying a liquid at a sufficient pressure and flow rate, and its peripheral members, regardless of the principle such as a gear pump, a trochoid pump, and a plunger pump. Power for operating the pump body 20 is supplied by rotating the drive shaft 16.

The pump body 20 is fixed to a partition 14 integrated with the chamber 13, and a suction space 22 is formed between the pump body 20 and the partition 14. The partition 14 is a suction space 22
Alternatively, the discharge space 24 and the upper space 26 are pressure-isolated. Similarly, a seal 23 is interposed between the surface that fixes the pump body 20 to the partition wall 14, and the suction space 22 and the discharge space 24 are pressure-isolated from each other. The drive shaft 16 is provided with a shaft seal 27 to prevent leakage of refrigerant from around the shaft.

The pipe passing through the chamber 13 from the liquid inlet 21 passes below the motor section 12, passes through the partition 14, and reaches the suction space 22. This flow path does not communicate with the upper space 26. The suction port (not shown) of the pump body 20 faces the suction space 22, and the discharge port (not shown)
Facing 4 The liquid outlet 25 is connected to the chamber 1 from the discharge space 24.
3 so as to penetrate and communicate with the outside.

The drive shaft 16 of the pump body 20 has a cantilever structure and is supported by bearings inside the pump body 20, extends upward through the upper partition wall 14, and fixes the rotor 17 of the motor. The stator 18 of the motor is fixed to the inner wall of the chamber 13. Power is supplied to the motor winding 19 attached to the stator 18 from the outside through a pressure-resistant insulating terminal (not shown) that penetrates the chamber 13 and conducts electricity but cannot pass fluid.

Two communication paths, a gas inlet 28 and a gas outlet 29, which communicate the upper space 26 containing the motor section 12 with the outside, are provided through the wall of the chamber 13. The gas inlet 28 and the gas outlet 29 are axially separated with the rotor 17 and the stator 18 interposed therebetween, and the flow of the refrigerant gas from the inlet to the outlet is a motor gap (a narrow gap between the rotor and the stator). (Clearance).

Next, the operation of this embodiment will be described.

In the cooling operation using ice heat storage mainly performed in the daytime in summer, the refrigerant circulates in the direction of the arrow shown in FIG. 1 using the liquid refrigerant pump 1 as a pressure source.

The refrigerant gas is cooled and liquefied by the heat of melting of the ice stored in the main heat storage tank 2 while passing through the heat exchanger 3 in the tank. The entire amount of the refrigerant in the four-way vortex that has exited the in-tank heat exchanger 3 is in a liquid phase, but is almost saturated at first. This is pressurized due to the difference in height when the liquid refrigerant pump 1 descends to a supercooled state.

The supercooled liquid refrigerant is sucked into the liquid refrigerant pump 1 from the liquid inlet 21. Liquid pumps generally have the potential to cause cavitation and other problems due to local pressure drop in the suction flow path. In the present embodiment, the liquid refrigerant is supercooled by utilizing the height difference, so that cavitation can be suppressed and stable operation can be expected.

In the liquid refrigerant pump 1 shown in FIG. 2, electric power supplied from the outside is used as rotation power by the motor section 12, and the pump body 20 is driven to rotate by the drive shaft 16. The liquid refrigerant is sucked from the liquid inlet 21 by the function of the pump body 20 and enters the compressor body 20 via the suction chamber 22. The liquid refrigerant that has been pressurized by the compressor body 20 and discharged into the discharge chamber 24 has a liquid outlet 25.
Sent out from.

The liquid refrigerant flowing out of the liquid outlet 25 enters the room through the outgoing pipe 5 and passes through the expansion valve 10. Here, since the pressure is reduced, vaporization and adiabatic expansion of the refrigerant begin, and the temperature decreases due to heat of vaporization and heat of expansion. In this state, the room passes through the indoor heat exchanger 8 and exchanges heat with room air, thereby cooling the room and simultaneously evaporating the refrigerant. When the entire amount of the refrigerant evaporates, the temperature of the refrigerant itself rises next.

After cooling the room, the refrigerant gas is returned to the return pipe 6
Through the gas inlet 28 into the upper space 26 of the liquid refrigerant pump 1. The motor unit 12 generates heat due to motor loss, and the refrigerant gas exchanges heat by passing near the heated rotor 17 and the stator 18 to cool them. Thereafter, the refrigerant gas exits from the gas outlet 29 and returns to the in-tank heat exchanger 3 of the ice heat storage tank 2 via the return pipe 7 to complete a cycle.

On the path from the upper space 26 to the suction space 22 through the in-tank heat exchanger 3, there is no large pressure loss, and conversely, there is no means for increasing the pressure. The difference is relatively small. The shaft seal 27 that separates these spaces may cause fluid leakage from the seal portion at a high pressure difference.
Since the differential pressure is small as described above, the leakage occurring there is negligible. Alternatively, it can be said that a shaft seal that is used for high pressure resistance and involves a large friction loss is unnecessary.

In this embodiment, the purpose can be achieved with a simple configuration having few valves and branches in the piping system. In the liquid refrigerant pump as well, the number of bearings is minimized and no power transmission parts such as shaft couplings are required, so that mechanical loss can be reduced, and simple and high efficiency can be expected. In addition, since there is little wear inside the liquid refrigerant pump, the generation of dust is also small. Further, there is no portion where the liquid refrigerant or the refrigerant gas stays inside the liquid refrigerant pump, and the stagnation of oil and dust contained in the refrigerant can be prevented.

In the present embodiment, a so-called vertical type in which the rotation axis is approximately vertical has been described as an example. However, the configuration, operation, and effects of a so-called horizontal type in which the direction of the rotation axis is approximately horizontal are also described. There is no difference. In addition, even if it is the same vertical type as the example, it is also possible to adopt a configuration in which the motor unit 12 is arranged below and the pump unit 11 is arranged above, contrary to the present embodiment. Can be expected. Since the direction of the inlet and outlet of the refrigerant is not related to the essence of the present invention, the refrigerant may be provided on either the outer periphery or the end surface of the substantially cylindrical chamber 13.

2. Hereinafter, the configuration and operation of a liquid refrigerant pump according to a second embodiment of the present invention and an ice storage type air conditioning system using the same will be described with reference to FIGS. FIG. 1 is a schematic diagram of a piping system of the ice storage air conditioning system according to the present embodiment. FIG. 4 is a schematic sectional view of a liquid refrigerant pump used in the air conditioning system of FIG. The description of the structure, operation, effects, and the like common to the first embodiment is omitted.

In FIG. 3, a short-circuit pipe connecting the middle of the return pipe 6 from the indoor heat exchanger 8 to the gas inlet 31 of the liquid refrigerant pump 1 and the middle of the return pipe 7 from the gas outlet 32 to the heat exchanger 3 in the tank. Then, a short-circuit valve 58 on the short-circuit pipe is provided. The short-circuit valve 58 may be of any type, such as a throttle with a fixed opening, a manually operated valve, or an electrically controlled valve.

The internal structure of the liquid refrigerant pump 1 used in the present embodiment will be described with reference to FIG. The rotating shaft 51 of the pump main body 20 and the rotating shaft 52 of the motor connected to the rotor 52 of the motor are separated from each other and are rotationally connected by a shaft coupling 53. The rotating shaft 52 of the motor is supported by an upper support beam 54 and a lower support beam 55 which are attached to the inner surface of the chamber 13, and the support portion constitutes a bearing. The upper support beam 54 and the lower support beam 55 are provided with openings 56 so as not to hinder the passage of the refrigerant gas.
In addition, the upper surfaces of the upper support beam 54 and the lower support beam 55 are formed in a concave shape, and are made lower toward the center. An outer peripheral flow path 57 is provided inside the wall material of the chamber 13 corresponding to the outside of the stator 18 of the motor.
Is open. The flow path from the liquid inlet 21 to the suction space 22 is formed by making a part of the partition wall 14 thick and forming a hole therein.

This embodiment operates in the same manner as the first embodiment, but differs only in the following points.

The entire amount of the refrigerant gas returning to the return pipe 6 is not used for cooling the motor section 12, and a part of the refrigerant gas passes directly to the downstream return pipe 7 through the short-circuit valve 58. The flow ratio of these two systems can also be adjusted by the opening degree of the short-circuit valve 58.

In the liquid refrigerant pump 1, the refrigerant gas entering from the gas inlet is divided into two parts. One is the opening 5
7 through a motor gap between the rotor 17 and the stator 18 to the clearance, the other going upward through the outer flow path. Both come together at the top of the upper space 26 and exit through the gas outlet.

In a normal refrigerant cycle, a small amount of oil is mixed in the refrigerant regardless of the gas phase or the liquid phase due to the mixing of compressor oil. Some of these adhere to the flow channel tube wall and the like, so that oil also adheres to the inside of the chamber 13. Since this oil has a higher specific gravity than the refrigerant gas, it tends to drip downward by gravity. Therefore, oil adhering above the upper support beam 54 and the lower support beam 55 gradually flows to the center of these beams. The central portion of these beams is a bearing that supports the rotating shaft 52, and is automatically lubricated by the flowing oil.

According to the present embodiment, since the flow rate of the refrigerant gas passing through the motor 12 can be adjusted, the pressure loss of the entire refrigerant cycle is reduced even when the pressure loss passing through the motor section is relatively large. be able to. Further, a gas-liquid separation means may be provided at a branch point from the return pipe 6 on the upstream side of the short-circuit valve 58. In that case, only the gas phase is supplied to the liquid refrigerant pump 1, and the liquid phase is piped so as to pass through a short circuit path. By doing so, even if the amount of heat exchange by the indoor heat exchanger 8 is smaller than a predetermined amount and the liquid phase is mixed into the return pipe 6, it is possible to prevent the liquid phase from entering the liquid refrigerant pump 1. The intrusion of the liquid phase causes an electric leakage in the motor section 12, so that a function for preventing the electric leakage is provided, which is preferable.

Since the rotation shaft of the liquid refrigerant pump 1 is separated by the pump unit and the motor unit, the rotation is stabilized and the bearing load is reduced, so that damage mainly to the bearing unit can be prevented and the service life can be extended. . Therefore, the reliability of the liquid refrigerant pump 1 and the whole ice heat storage system can be improved. Further, since the supply of the lubricating oil to the motor section is automatically performed, a means for supplying the oil is unnecessary.

[0040]

According to the present invention, by closing the liquid refrigerant pump, all the containers and piping systems filled with the refrigerant including the liquid refrigerant pump 1 are completely shut off from the outside air, so that the refrigerant is dissipated and the outside air is discharged. Moisture ingress can be prevented. In addition, the cooling of the motor, which is difficult due to the hermetically sealed type, is ensured by using the refrigerant gas, so that the motor is prevented from overheating, and at the same time, the motor winding does not sink into the liquid refrigerant and does not cause any trouble such as leakage. Therefore, the efficiency and reliability of the liquid refrigerant pump and the ice storage type air conditioning system using the same can be improved.

Further, since the motor is efficiently cooled, high efficiency can be expected. In addition, since the motor and the pump main body are directly connected to each other, power transmission loss is very small, and the internal flow of the refrigerant in the middle of the refrigerant flow is reduced. Since the leakage and the pressure loss are small, the energy efficiency of the liquid refrigerant pump and the ice storage type air conditioning system as a whole is also excellent.

[Brief description of the drawings]

FIG. 1 is a system diagram of an ice storage type air conditioning system according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a structure of a closed type liquid refrigerant pump used in the system of FIG. 1 of the present invention.

FIG. 3 is a system diagram of an ice storage type air conditioning system according to a second embodiment of the present invention.

FIG. 4 is a schematic sectional view showing the structure of a closed type liquid refrigerant pump used in the system of FIG. 3 of the present invention.

[Explanation of symbols]

1 ... Liquid refrigerant pump, 2 ... Main heat storage tank, 3 ... Heat exchanger in tank,
4, 5 ... outgoing piping, 6, 7 ... returning piping, 8 ... indoor heat exchanger, 9 ... fan, 10 ... expansion valve, 11 ... pump part, 12
... Motor part, 13 ... Chamber, 14 ... Partition wall, 16 ... Drive shaft, 17 ... Rotor, 18 ... Stator, 19 ... Motor winding, 20 ... Pump body, 21 ... Liquid inlet, 22 ... Suction space, 23 ... Seal, 24: discharge space, 25: liquid outlet, 2
6 ... upper space, 27 ... shaft seal, 28 ... gas inlet, 29
... gas outlet, 51 ... pump shaft, 52 ... motor shaft, 53 ...
Shaft joints, 54, 55 ... support beams, 56 ... beam openings, 5
7: outer peripheral flow path, 58: short circuit valve.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Sadamori 502 Kandachicho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. (72) Takao Chiaki 390 Muramatsu, Shimizu-shi, Shizuoka Pref. Hitachi Air Conditioning System Co., Ltd. (72) Inventor Yasuho Nishimura 390 Muramatsu, Shimizu-shi, Shizuoka F-term in Hitachi Air Conditioning System Co., Ltd. (reference) 3H035 AA01 AA07

Claims (1)

[Claims] 1. A pump having a function of supplying a liquid under pressure, a motor for driving the pump, a drive shaft for transmitting rotational power generated by the motor to the pump, and these components. A liquid refrigerant pump provided with a chamber which is a pressure vessel accommodating the inside of the liquid refrigerant pump, the motor part and the pump part are pressure-isolated from each other, and the pump part penetrates the chamber wall surface and communicates with the outside. Two communication passages, each of which serves as an inlet and an outlet for the liquid refrigerant, and further, the motor unit has at least two communication passages penetrating through the chamber wall and communicating with the outside, each of which has a refrigerant gas flow. A liquid refrigerant pump that functions as an inlet and an outlet.