JPS60128990A - Double stage rotary compressor - Google Patents

Abstract

PURPOSE:To reduce torque variation of compressor by making the displacement of high pressure side compression element of double stage rotary compressor lower than that at the low pressure side while shifting the phase of compression strokes of both compression elements by 180 deg.. CONSTITUTION:The compressor 3 is containing a motor 14 in the upper section of an enclosed container 3a while a rotary compression element where high and low pressure compression elements 5, 4 are laminated integrally through an intermediate partition is contained in the lower section of motor 14. The displacement of high pressure compression element 5 is made 0.45-0.65 times that of low pressure compression element while the phase of compression stroke of high pressure compression element 5 is shifted by 180 deg. from that of low pressure compression element.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to rotary two-stage compressors, and more particularly to rotary two-stage compressors.

The present invention relates to a rotary two-stage compressor used in a two-stage compression refrigeration cycle, which is suitable for a refrigeration cycle with a large temperature drop such as a heat pump water heater, and a refrigeration cycle of a heat pump room near conditioner.

[Background of the invention]

Conventionally, a single-stage compression refrigeration cycle is generally used in a refrigeration cycle in which there is a large temperature difference between evaporation temperature and condensation temperature, such as in a heat pump water heater. A single-stage compression refrigeration cycle is also used in heat pump type room near conditioners.

However, in heat pump water heaters and heat pump room air conditioners, LFC using a two-stage compression refrigeration cycle improves the efficiency of the refrigeration cycle compared to using a single-stage compression refrigeration cycle. In the case of a heat pump water heater with a large temperature, the compressor discharge temperature can be lowered, so overheating of the compressor can be prevented.

However, in the past, there was almost no experience of using a rotary two-stage compressor in a two-stage compression refrigeration cycle, so the coefficient of performance of the two-stage compression refrigeration cycle was set to -large, and the load torque of the rotary two-stage compressor was The structure of a two-stage rotary compressor that can reduce fluctuations in power (that is, reduce vibration and noise) is unknown, and this is the key to the practical application of a two-stage compression refrigeration cycle that uses a two-stage rotary compressor. was inhibiting.

[Purpose of the invention]

The present invention solves the above-mentioned 17 problems of the prior art and achieves
The object of the present invention is to provide a rotary two-stage compressor that can maximize the coefficient of performance of a two-stage compression refrigeration cycle and has small fluctuations in its own load torque.

[W essential of invention]

The structure of the rotary two-stage compressor according to the present invention is such that the electric motor is housed in the upper part of the V-closed container, and the high-pressure compression element and the low-pressure compression element are stacked and integrated in a stacked manner with an intermediate partition plate interposed therebetween. In a rotary two-stage compressor in which a rotary compression element is connected and housed in the lower part of the electric motor, the displacement amount of the high-pressure pressure a element is 045 to 0 of the displacement amount of the low-pressure compression element. ．．
60 times, and the phase difference between the phase of the compression stroke of the high pressure compression element and the phase of the compression stroke of the low pressure compression element is 1.
The angle is 80 degrees.

[Embodiments of the invention]

An example of the rotary two-stage compressor of the present invention will be described below using an example in which it is applied to a heat pump water heater.

FIG. 1 is a longitudinal sectional view of a rotary two-stage compressor according to an embodiment of the present invention, and FIG. 2 is a cycle configuration diagram of a heat pump water heater using the rotary two-stage compressor according to FIG. It is.

First, a rotary two-stage compressor will be explained using FIG. This rotary two-stage compressor 3 has an electric motor 14 housed in the upper part of the closed container 3a.

A rotary compression element made by laminating and integrating a high-pressure compression element 5 and a low-pressure compression element 4 via an intermediate partition plate 15 is connected to the lower part of the electric motor 14 and housed therein. Displacement amount V of 5, displacement of compression element 4 for low pressure *
+00.45 to 0.60 times (Details will be described later using Fig. 3.4) % 1 The phase of the compression stroke of the compression element 5 for high pressure and the phase of the compression stroke of the compression element 4 for low pressure Phase difference total 18
0 degree (details will be described later using FIG. 5).

To explain in more detail, 18 is an eccentric portion 18α.

The low-pressure compression element 4 is connected to a cylinder 17, a roller 20 which is eccentrically rotated inside the cylinder 17 by an eccentric portion 18A of the crankshaft 18, and a roller 220 that contacts the cylinder 17. a vane (not shown) that partitions the interior into a high pressure chamber and a low pressure chamber; a lower end face plate 22 that closes the opening below the cylinder 17 and has a bearing portion 22a' of the crankshaft 18; A cover 23 closes the lower end surface of the discharge chamber 22A to form a sealed discharge chamber 22A. On the other hand, the high-pressure compression element 5 includes a cylinder 16, a roller 19 eccentrically rotated by an eccentric portion 18cL of the entire crankshaft 18 in the cylinder 16, and a cylinder 19 in contact with the roller 19.
A vane (not shown) that divides the inside of 6 into a high pressure chamber and a low pressure chamber
, the opening above the cylinder 16 is closed, and the crankshaft 1 is closed.
It consists of an upper end face plate 21 having a bearing portion 21α of B, and a discharge cover 24 attached to the upper face of this upper end face plate 21. Further, 1 and 4α are suction pipes, 4b are discharge pipes of the low-pressure compression element 4, 5α are suction pipes of the high-pressure compression elements 5, and 3
b is a discharge pipe.

Next, a heat pump hot water supply system in which this two-stage rotary compressor 3 is housed in the hot water supply unit 2 will be described using FIG. 2.

1 is a hot water storage tank for storing hot water for hot water supply, and 11 is a water supply valve for replenishing water into the hot water storage tank 1.

12 is a pump that exchanges heat with the hot water supply heat exchanger 6 in the hot water supply unit 2 to be described later, and then circulates the water in the hot water storage tank 1 again into the hot water storage tank 1; 13 is a hot water tap.

To explain the details of the hot water supply unit 2, 6 is a hot water supply heat exchanger, 7a, 7, which radiates heat and liquefies the high-pressure refrigerant gas from the discharge pipe 3b of the rotary two-stage compressor 3, and has a function as a condenser. ．． b is a condenser-side pressure reducer that reduces the pressure and temperature of the liquid refrigerant, and an evaporator-side pressure reducer 7a;
The gas-liquid separator 8 is connected for 7 hours. 8aFi is an intercooler disposed in the gas-liquid separator 8 and cools the superheated refrigerant gas discharged from the low-pressure compression element 4; Bb is the gas refrigerant separated and evaporated in the gas-liquid separator 8; This gas extraction pipe 8b is a gas extraction pipe drawn out from the top, and a reverse valve 8C is disposed in the middle of the gas extraction pipe 8b, and the tip thereof is connected to the outlet side of the intercooler 8G.

The check valve 8C prevents the refrigerant from flowing in the opposite direction, that is, into the gas-liquid separator 8. 9 is an outdoor heat exchanger that absorbs heat and gasifies the depressurized two-phase refrigerant and functions as an evaporator; 9a is a blower that blows air to the outdoor heat exchanger 9; 10 is a rotary two-stage This is an accumulator that prevents liquid refrigerant from being sucked into the compressor 3.

Here, the above-mentioned high pressure compression element 5 is pushed away:! t'
* k Low pressure pressure #1 element 4 displacement force V, 0045~0
．． 60 and the reason why the phase difference between the compression stroke of the high-pressure compression element 5 and the compression stroke of the low-pressure compression element 4 is set to 180 degrees are shown in FIG. 3.4, respectively.

This will be explained using FIG.

Figure 3 shows the relationship between the displacement ratio of the rotary two-stage compressor and the average coefficient of performance when the heat pump water heater according to Figure 2 heats the water supply from a temperature of 15°C to a boiling temperature of 80°C. Figure 4 shows the displacement ratio of the rotary two-stage compressor in a heat pump room air conditioner system incorporating the rotary two-stage compressor shown in Figure 1. 't/' indicates the relationship between and the coefficient of performance.
It is an I-□ diagram.

According to the research conducted by the present inventors, the heat pump water heater shown in Figure 2 has an average coefficient of performance of ) (average value of coefficient of performance cap when heating from 15°C to 80°C) and high pressure compression element 5
and the displacement amount V of the low-pressure compression element 4, that is, the displacement ratio of the rotary two-stage compressor V, /V
.

Figure 3 shows the relationship between the average performance coefficient cap
It has been found that the displacement ratio 't/'+ at which the maximum is approximately 053.

On the other hand, a heat pump type room air conditioner digital camera incorporating the rotary two-stage compressor 3 according to Fig. 1 (not shown)
The relationship between the coefficient of performance Cop of During heating operation at a temperature of 45 to 60°C, the displacement ratio V*/' is 0.4
5 to 0.55, the coefficient of performance is maximum, and the temperature of the air blown out of the condenser (outdoor heat exchanger) is approximately 37 degrees Celsius! ! When turning, the displacement ratio Vt/V is approximately 06
It was found that the coefficient of performance was maximum at 0.

FIG. 5 shows the phase difference between the compression stroke of the high-pressure compression element and the compression stroke of the low-pressure compression element of the rotary two-stage compressor according to FIG. 1, and the relationship between the torque fluctuation rate. It is a torque fluctuation rate diagram.

The present inventors changed the phase difference between the phase of the compression stroke of the high-pressure compression element 5 and the phase of the compression stroke of the low-pressure compression element 4 to
When set to 0%.

When examining the torque fluctuation range/average torque).

As shown in Fig. 5, it was found that the torque fluctuation rate was the smallest when one phase difference was 180 degrees.

Based on the research results described above, the rotary two-stage compressor used in the two-stage compression refrigeration cycle for heat-bonf water heaters and heat-pump room air conditioners has been designed to maximize the overall coefficient of performance of the cold-water cycle. Therefore, the displacement ratio should be set to 045 to 060, and the phase difference of the compression stroke should be set to 18 to minimize the variation in load torque.
All you have to do is set it to 0 degrees.

As mentioned above, the rotary two-stage compressor 6 for the heat pump hot water supply lid has a displacement ratio V, /V of approximately 0.
When the average coefficient of performance is 55, the average coefficient of performance is at its maximum, but if you use a coefficient of 7/'1 = 045 to 0.60, taking into account changes in outside air conditions, your father-in-law will always be able to operate the heat pump water heater near the maximum value. Can drive.

A rotary two-stage compressor 5 made of K11lt like this
The operation of the heat pump hot water supply system will be explained using FIG. 2 again.

Water is supplied from the water supply valve 11 into the hot water storage tank 1, and the hot water storage tank 1 is filled with water. Here, when the heat pump water heater fON is turned on, the pump 12° rotary two-stage compressor 3. The blower 9α is diverted.

First, to explain the flow of the refrigerant, the refrigerant is sucked into the rotary two-stage compressor from the suction pipe 4a, and the low-pressure compression element 4
The superheated gas refrigerant compressed by It is sucked into the compression element 5, further compressed by the high-pressure compression element 5, and discharged into the closed container 3α. The refrigerant discharged from the closed container 3α through the discharge pipe 31 is
Heat exchanger for hot water supply6. The liquid refrigerant enters the gas-liquid separator 8 from the condenser-side pressure reducer 7α, and the liquid refrigerant separated here passes through the evaporator-side pressure reducer 7b and the outdoor heat exchanger 9, and is sucked into the low-pressure compression element 4 and circulated. It is a two-stage compression refrigeration cycle.

The above cycle will be explained using the entire Mollier diagram.

FIG. 6 is a Mollier diagram of the two-stage compression refrigeration cycle of the heat pump water heater according to FIG. 2. In FIG. 6, A-+B is the first compression process by the low-pressure compression element 4, C-+D is the second-stage compression process by the high-pressure compression element 5, and D-+E is the hot water supply heat exchanger. 6, the condensation m process, E-+F is the expansion process due to the condenser side pressure reducer 7α, G→
H is the expansion process by the evaporator side pressure reducer 7b, and H→A is the evaporation process by the outdoor heat exchanger 9. The gas refrigerant generated from the high-pressure liquid refrigerant during the expansion process of E-pF is separated by the gas-liquid separator 8, extracted at intermediate pressure, and sucked into the high-pressure compression element 5. In addition, the intercooler 8aK in the gas-liquid separator 8 and the low-pressure compression element 4'! ! - The gas refrigerant that comes out is cooled to lower its temperature, and the enthalpy of the second-stage suction gas is lowered (E − + C).

It looks like this.

Therefore, the two-stage compression refrigeration cycle of the heat pump water heater according to FIG. 2, shown by the solid line, reduces wasteful expansion and compression work compared to the single-stage compression refrigeration cycle shown by the broken line.

On the other hand, to explain the flow of water, water in the hot water storage tank 1 is sent to the hot water supply heat exchanger 6 by the pump 12.

Here, the water is heated by the heat radiation of the two-stage compression refrigeration cycle, and the water whose temperature has increased flows back into the hot water storage tank 1. When the water temperature in the hot water storage tank 1 reaches a predetermined boiling temperature (up to about 80°C for hot water supply applications), the heat pump water heater is turned off and the pump 12. Rotary two-stage compressor 3. The operation of the blower 9a is stopped.

The boiled hot water is drawn out from the top of the hot water storage tank 1 and used through the hot water tap 13 as needed.

According to the embodiment described above, it is possible to shift the phase of the compression stroke of each pressure element 4°5 by 180 degrees, and the electric motor 14
Reduces vibration and noise by minimizing torque fluctuations applied to
In addition, the ratio between the displacement 'JIFI of the low-pressure compression element 4 and the displacement R of the high-pressure compression element 5 't0.45 to 0. /lo
By doing so, it is possible to put into practical use a heat pump water heater with optimal performance (that is, a large average coefficient of performance) using a 3'ft rotary two-stage compressor.

In the above embodiment, the rotary two-stage compressor of the present invention is used in a heat pump water heater, but the rotary two-stage compressor with the above configuration is used in a heat pump room air conditioner. It is also possible to put into practical use a heat pump type room air conditioner with an excellent coefficient of performance.

〔Effect of the invention〕

As explained in detail above, the present invention provides a rotary two-stage compressor that can maximize the coefficient of performance of a two-stage compression refrigeration cycle and has small fluctuations in its own load and torque. I can do it.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a rotary two-stage compressor according to an embodiment of the present invention, and FIG. 2 is a cycle configuration diagram of a heat pump water heater using all of the rotary two-stage compressors according to FIG. 1. , FIG. 3 shows the displacement ratio and average coefficient of performance of the rotary two-stage compressor when the heat pump water heater according to FIG. V, /V, -〇 diagram showing the relationship between
The figure shows the relationship between the displacement ratio of the rotary two-stage compressor and the coefficient of performance of the heat pump room near conditioner incorporating the rotary two-stage compressor shown in FIG.
/V, -cap diagram, Fig. 5 shows the phase difference between the compression stroke of the high pressure compression element and the compression stroke of the low pressure m element of the rotary two-stage compressor shown in Fig. 1, and the torque. The phase difference-torque fluctuation rate diagram showing the relationship with the fluctuation rate, FIG.
FIG. 2 is a Mollier diagram of a two-stage compression refrigeration cycle of the heat pump water heater according to the figure. 3... Rotary two-stage compressor 3α... Closed container 4... Low pressure compression element 5...
Compression element for high pressure 14...Electric motor 15...Intermediate partition plate V,...Displacement amount V of compression element for low pressure,...Displacement amount ratio of compression element for high pressure 1 Figure 2 do93 mantle firework R engineering + dop m figure 'HM

Claims (1)

[Claims] 1. In a closed container, an electric motor is housed in the upper part, and a rotary compression element, which is an integrated structure in which a high-pressure compression element and a low-pressure compression element are laminated and integrated, is connected to the lower part of the electric motor via an intermediate partition plate. In a rotary two-stage compressor that is housed in
The displacement amount of the high-pressure compression element is set to 0.45 to 0.60 times the displacement amount of the low-pressure compression element, and the phase of the compression stroke of the high-pressure compression element and the compression stroke of the low-pressure compression element A rotary two-stage compressor characterized by having a phase difference of 180 degrees with respect to the phase of the rotary compressor.