JP2559450B2 - Operating method of scroll compressor equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for operating a scroll compressor facility configured by connecting a plurality of scroll compressors in parallel.

[Conventional technology]

Regarding this type of scroll compressor equipment,
No. -67978 and Japanese Utility Model Laid-Open No. 62-271984.

Next, a conventional example of a scroll compressor facility including two scroll compressors will be described with reference to FIGS. 3 to 5.

In the conventional scroll compressor equipment shown in FIG. 3, the first starting scroll compressor 1 and the second starting scroll compressor 2 are housed in a common high pressure container 3.
Independent suction ports 4 are provided at both ends of the, and a common discharge port 5 is provided at the center thereof.

FIG. 4 shows the structure of the scroll compression mechanism portion including the suction port 4. The suction gas pushes open the suction check valve 7 provided in the fixed scroll 6 and enters the outer periphery of the scroll vortex,
After being compressed between the fixed scroll 6 and the orbiting scroll 8, it is discharged into the high-pressure container 3 from the discharge port 9 at the center of the fixed scroll 8. Further, this compressor is provided with an overcompression prevention valve 10 in order to prevent overcompression when the compression starts from a state where the pressure on the low pressure side is high such as at startup.

FIG. 5 shows a cross section perpendicular to the axis of the compression mechanism section, in which the fixed scroll 6 and the orbiting scroll 8 are arranged downstream of the suction check valve 7 in order from the outer peripheral portion of the suction chamber 11,1 pair of low pressure chambers 12,1 pair. A pressure chamber 13 and a high pressure chamber 14 are formed. The figure shows the low-pressure chamber 12
Shows the state where the closing of the suction chamber is completed, but when the orbiting scroll 8 orbits counterclockwise from this state, the suction chamber is closed.
Each room except 11 advances to the center of the vortex while decreasing in volume, and compression progresses.

When the compressor is operating stably, the pressure in the suction chamber 11 is the compressor suction pressure, and the pressure rises in the order of the low pressure chamber 12 and the intermediate pressure chamber 13, and the pressure in the high pressure chamber 14 becomes that of the high pressure container 3. It becomes equal to the pressure (discharge pressure). On the other hand, while the compressor is stopped, the pressure in all the chambers downstream of the suction check valve 7 becomes equal to the pressure in the high-pressure container 3.

[Problems to be Solved by the Invention]

In the scroll compressor, when compression is performed, the low pressure chamber 12, the intermediate pressure chamber 13, the high pressure chamber 14, and the pressure difference between the pressure in each chamber and the pressure in the suction chamber 11 cause the scroll scroll 8 to rotate in a direction perpendicular to the eccentric direction. A radial load F (see FIG. 5) that pushes the scroll 8 is generated, and the product of this load and the orbiting radius of the orbiting scroll 8 is the theoretical torque of the compressor.

In a single compressor, the start-up operation is generally performed with the suction side pressure and the discharge side pressure of the compressor being in the same balance. However, in the twin scroll compressor shown in FIG. 3, when the compressor 2 is started while only one compressor 1 is operating, there is a large pressure difference between the suction pressure and the discharge pressure.

Considering the pressure state of each room at the time of starting the second (late start side) compressor with reference to FIG. 5, the suction chamber 11 and the low pressure chamber 1 before the start.
2, the pressures in the medium pressure chamber 13 and the high pressure chamber 14 are all equal to the discharge pressure of the first compressor. As the orbiting scroll 8 orbits from this state, the pressures in the low pressure chamber 12 and the intermediate pressure chamber 13 increase in accordance with the decrease in volume, but for the first rotation, this pressure increase value is determined only by the initial discharge pressure. , It does not change depending on the suction side pressure.

On the other hand, the suction chamber 11 has a low pressure chamber 12, a medium pressure chamber 13, and a high pressure chamber.
Since the volume increases by the volume decrease of 14, the pressure decreases. In the case of normal balance start-up, if the pressure in the suction chamber 11 drops even slightly, the suction check valve 7 opens and gas at the balance pressure enters, but when starting the second twin scroll compressor, the suction chamber 11 If the pressure does not drop to the suction pressure of the first compressor, the suction check valve 7 does not open, so the pressure in the suction chamber 11 continues to drop to the suction pressure.

As described above, the radial load F and the torque of the scroll compressor are generated by the pressure difference between each room and the suction chamber 11, so that the torque of the second compressor start-up is the suction chamber when the discharge pressure is constant. Since the pressures of the rooms other than 11 are constant, the lower the suction pressure, the larger the value.

For the above reason, the starting condition of the second compressor of the twin scroll compressor is more severe than that of the first compressor, and it may not be possible to start due to insufficient torque of the motor or overcurrent (in the case of starting the inverter, etc.).

Possible countermeasures include (i) increasing the torque of the motor, (ii) stopping the first motor before starting the second motor, and then starting the motors at the same time. With such a design change, with respect to (ii), the capacity must be set to 0 once when the second unit is activated in response to the capacity increase request.

It is an object of the present invention to reduce the starting torque when starting a later-start compressor of a twin scroll compressor that can be operated in parallel, and to make it possible to start the later-start compressor without the above-mentioned changes. To do.

[Means for solving the problem]

In order to achieve the above object, the operating method of the scroll compressor facility of the present invention is configured based on the following basic principle.

That is, in the case of the twin scroll compressor, the starting torque can be reduced by raising the pressure of the suction chamber 10 to a high pressure for a predetermined time when starting the second unit.

As a concrete measure for increasing the pressure in the suction chamber, the high-pressure gas of the pre-starting scroll compressor that has already started operating is sent to the suction side of the late-starting scroll compressor.

[Action]

In the case of the twin scroll compressor, when the suction side pressure of the subsequent startup scroll compressor is increased, the startup torque of the subsequent startup scroll compressor is reduced.

The same applies to a scroll compressor facility composed of three or more scroll compressors.

〔Example〕

FIG. 1 shows an embodiment of the present invention. This embodiment is an improvement of the scroll compressor equipment of the conventional example shown in FIG.

In the present embodiment, as in the conventional example, a common suction pipe 31 that communicates the suction ports 4, 4 of the two scroll compressors and a discharge pipe 23 that communicates with the discharge port 9 of each scroll compressor.
Are provided. Further, the suction chamber introduction port 15 provided in the late start scroll compressor 2 and the discharge pipe 23 are connected by a bypass pipe 32 with a bypass valve 16 interposed. According to the present embodiment, by opening the bypass valve 16 for a predetermined time when the late starting scroll compressor 2 is started, the pressure in the suction chamber 10 downstream of the suction check valve 7 can be made high and the starting torque can be reduced. I can.

When the bypass valve 16 is closed after starting, the suction chamber 11 (the fifth
Although the pressure in the figure decreases, when the stable operation state is entered, the low pressure chamber
11. Since the pressure in the medium pressure chamber 12 also decreases, the torque becomes lower than that at the start.

FIG. 2 shows another embodiment of the present invention, which is an example of a twin scroll compressor in which the suction and discharge pipes of two scroll compressors are connected to each other.

That is, also in this embodiment, the suction ports 4, 4 of the two scroll compressors are communicated with each other through the common suction pipe 31, and the discharge ports 9a, 9a are communicated with each other through the common discharge pipe 23. Further, in this embodiment, a suction pipe isolation valve 20 is provided separately from the above-described suction check valve 7 built in the compressor, and a bypass valve 21 is interposed between the suction pipe and the discharge pipe on the side of the downstream dynamic compressor 18. It is connected by a bypass pipe 32.

In the present embodiment, by closing the suction pipe separation valve 20 and opening the bypass valve 21 at the same time for a certain period of time when the start-up scroll compressor 18 is started up, a part of the discharge gas is sucked back into the start-up scroll compressor 18 to be reversed. Valve 7 (not shown in FIG. 2,
Open (see Fig. 4) and let it flow into the suction chamber 11 (Fig. 5),
The starting torque is reduced by increasing the pressure in the suction chamber 11.

Although not shown, as still another embodiment, in a scroll compressor in which a plurality of compressors are connected in the same container, a part of the discharge gas flows into the suction chamber to the second and subsequent starting compressors. Providing a biasing means increases the pressure in the suction chamber to reduce the starting torque.

Further, as still another embodiment, in a scroll compressor in which suction and discharge pipes of a plurality of scroll compressors are externally connected, the bypass device is provided in the second and subsequent starting compressors. Also in this case, the starting torque can be reduced.

〔The invention's effect〕

According to the present invention, in a scroll compressor facility having a structure in which a plurality of scroll compressors are connected in parallel, by increasing the suction side pressure of the subsequent startup scroll compressor at startup, the startup torque of the subsequent startup scroll compressor is reduced. can do.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the scroll compressor facility of the present invention with a piping system diagram added. FIG. 2 is an explanatory diagram of another embodiment of the present invention. FIG. 3 shows a conventional scroll compressor facility, and an explanatory view in which a piping diagram is added to a vertical sectional view thereof, FIGS. 4 and 5 show details of the scroll compressor, and FIG. FIG. 5 is a partially enlarged horizontal sectional view, and FIG. 1 ... Start-up scroll compressor, 2 ... Later start-up scroll compressor, 3 ... High pressure container, 4 ... Suction port, 5 ...
Discharge port, 6 ... Fixed scroll, 7 ... Suction check valve, 8
...... Swirl scroll, 9 …… Discharge port, 10 …… Overcompression prevention valve, 11 …… Suction chamber, 12 …… Low pressure chamber, 13 …… Medium pressure chamber,
14 …… High pressure chamber, 15 …… Suction chamber inlet, 16 …… Bypass valve, 17 …… Next start scroll compressor, 18 …… Later start scroll compressor, 19 …… Oil pipe, 20 …… Suction pipe Separation valve, 21 …… Bypass valve, 23 …… Discharge piping.

Claims (2)

(57) [Claims] 1. A plurality of scroll compressors (1,3; 17,18)
Common suction pipe (31) communicating with each suction port (4,4)
And a common discharge pipe (32) communicating with each discharge port (9, 9; 9a, 9a), it is a method of operating scroll compressor equipment that enables parallel operation of multiple scroll compressors. Then, when the scroll start compressor (3; 18) is started after the start start scroll compressor (1; 17) of the plurality of scroll compressors is started, the common discharge pipe and the start start are performed. A method for operating scroll compressor equipment, characterized in that an on-off valve (16; 21) provided in a pipe (32) communicating with a suction chamber (11) of the scroll compressor is opened for a predetermined time. 2. The method of operating a scroll compressor facility according to claim 1, wherein the scroll compressor facility has two scroll compressors arranged to face each other in a closed container.