JPH01267381A - Scroll compressor provided with bypass pipe on ejection side - Google Patents

Abstract

PURPOSE:To lessen the influence by pressure reduction in a main pipe, and to reduce the discharging temperature of a compressor by providing a bypass pipe for communicating to a pressure lower than the operating pressure or the atmospheric pressure in addition the main pipe on the discharging port of the compressor, and interposing a continuous switch gear on the thereof. CONSTITUTION:A spiral member 1a provided on the upper surface of a turning scroll 1 is installed eccentrically to a spiral member 2a provided on the inside surface on the upper side of a fixed scroll 2 additional serving as an upper side casing. Fluid sucked from a suction port 3 is discharged from a discharging port 4 located in a central area by turning eccentrically the turning scroll 1. In such a compressor, a bypass pipe 21 whose one end is opened to a pressure Pa lower than the operating pressure, is connected to a main pipe 6 connected to the discharging port 4, and a continuous rotating valve 22 is interposed on the way thereof. The continuous rotating valve 22 is rotated so that a part of discharged fluid is discharged to a low pressure Pa part, when its operation is carried out by the operation pressure higher than the prescribed pressure generated from the proper incorporated internal compression ratio of the compressor.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a scroll device (volute compressor) used for compressing and suctioning gas such as air, gas, water vapor, etc. It relates to scroll compressors operating at higher pressures than those produced by their inherent built-in internal compression ratios.

[Conventional technology]

As shown in FIG. 2, a conventional scroll device has an orbiting scroll (1a) having one spiral member 1a wound spirally.
A fixed scroll 2, which also serves as an upper casing and has a spiral member 2a of the same shape formed to overlap the spiral member 1a, is provided so as to face each other eccentrically (the amount of eccentricity e). The fixed scroll 2 is provided with a suction port 3 on its outer periphery for sucking fluid when used as a compressor, and a discharge port 4 in its center. The discharge port 4 is connected to an air tank 7 via a main pipe 6 having a check valve 5 in the middle, and the air is discharged from the air tank 7 at an operating pressure Pd.

On the other hand, the orbiting scroll 1 is supported by a bearing 8, and is driven via a shaft 9 corresponding to a rotor whose upper part is eccentric by an eccentric amount (swivel radius) e and is rotated in the direction of the arrow. A balance weight (not shown) is provided on the shaft 9. In the figure, IO is a thrust bearing and rotation prevention mechanism, and 11 is a lower casing.

FIG. 3 is a PV diagram of compression in a compressor that performs internal compression, including the orbiting scroll device. Vl: inlet volume, V2: outlet volume (volume determined by volume ratio including Ml), Pd: operating pressure (operating discharge pressure).

The built-in internal compression ratio (P2/P,) is defined by the following theoretical formula.

(Pg/PI) = (V+/Vz)' where n: Polytropic index (Vl/V2) 7 Built-in volume ratio However, the operating pressure Pd sent out from the air tank 7
is the pressure P caused by the built-in internal compression ratio unique to the compressor.
If it is higher than 2, it is operated at the point ■→■→■.

[Problem to be solved by the invention]

As mentioned above, in a conventional scroll compressor, the pressure P generated by the built-in internal compression ratio (Pg/Pt) unique to the compressor is
When operating at a pressure Pd higher than t, for example, the discharge temperature Td is approximately 140'C.

As mentioned above, when the compressor is operated at a pressure lower than the operating pressure Pd on the discharge side or without a bypass pipe leading to atmospheric pressure, the compressor discharge temperature Td becomes high due to the heat of gas compression, and the temperature of the orbiting scroll 1 increases. There was a problem in that heat affected the back part (lower part in the figure), the bearing 8, and the rotor (shaft) part 9, causing strength problems and shortening the mechanical life.

SUMMARY OF THE INVENTION An object of the present invention is to provide a scroll compressor in which the influence of pressure drop in the main pipe is reduced and the discharge temperature of the compressor is lowered to extend the mechanical life.

[Means for Solving the Problem] In order to achieve the above object, the present invention provides a scroll compressor that operates at a pressure higher than the pressure generated by the built-in internal compression ratio unique to the compressor (in the case of an internal compression ratio of 1.0). Also included.

), a bypass pipe communicating with a pressure lower than the operating pressure or atmospheric pressure is provided outside the main pipe at the discharge port of the compressor, and a continuous opening/closing device using rotation or reciprocating motion is provided in the bypass pipe, and the main pipe It is characterized by minimizing the influence of internal pressure drop and lowering the discharge temperature.

By changing the area of the opening of the continuous switching device provided in the bypass pipe, the discharge temperature of the compressor can be adjusted, and the opening/closing speed of the continuous switching device can be changed. This makes it possible to adjust the discharge temperature of the compressor.

[For production]

Since the present invention is configured as described above, during operation, compressible fluids such as air, gas, and steam sucked in from the suction port are transferred to the spiral members of the orbiting scroll by the orbiting (revolution) movement of the orbiting scroll. As the liquid rotates while sequentially moving its contact point (position) from the periphery to the center with respect to the spiral member of the fixed scroll, it is transferred under pressure to the center and is discharged to the outside from the discharge port in the center. is no different from the conventional one.

However, in the present invention, during operation, when the switching device in the bypass pipe is opened, fluid flows through the bypass pipe, and when it is closed, the flow to the bypass pipe is stopped and fluid flows to the main pipe. Therefore, the discharge pressure of the compressor is higher than the operating pressure, i.e. the pressure produced by the compressor's own built-in internal compression ratio (
Since the operating pressure (operating pressure) alternates with a pressure lower than the operating pressure or atmospheric pressure, the discharge temperature when the switchgear is open is low, and when the switchgear is closed, the discharge temperature is high, and the average discharge temperature is low.

In addition, since the bypass pipe is continuously and alternately opened and closed over a certain number of cycles, the effect of pressure drop in the main pipe is reduced, and as mentioned above, the discharge temperature of the compressor can be lowered. , the mechanical life can be extended.

Furthermore, the discharge temperature of the compressor can be adjusted (controlled) by changing the opening area, the opening/closing speed, or both of the opening/closing device provided in the bypass pipe.

When the continuous opening/closing device provided in the bypass pipe is opened to release air to the atmosphere, the operation is performed at points ■→■→■ in FIG.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of essential parts of a scroll compressor showing an embodiment of the present invention, and in the figure, the same reference numerals as those shown in FIG. 2 indicate the same or similar parts.

In the figure, the spiral member 1a on the upper surface of the orbiting scroll 1 is eccentrically installed by a revolution radius e from the spiral member 2a on the upper inner surface of the fixed scroll 2, which also serves as an upper casing, and the orbiting scroll 1 is rotated by the rotation of the shaft 4. As the coil rotates eccentrically, the contact points between the spiral members 1a and 2a move from the periphery to the center, and fluid is sucked in from the suction port 3 and discharged from the discharge port 4 in the center. The discharge port 4 is connected to an air tank 7 via a main pipe 6 equipped with a check valve 5, and the operating pressure Pd is connected to the air tank 7 from the air tank 7.
The point that it is sent out as , is different from the conventional one (
There is no difference from Figure 2).

In the figure, 8 is a bearing, 9 is a shaft corresponding to a rotor, 10 is a thrust bearing and rotation prevention mechanism, and 11 is a lower casing.

In this embodiment (the present invention), a bypass pipe 21 whose one end is open to a pressure Pa lower than the operating pressure is connected to the main pipe 6 connected to the discharge port 4 in the center. is provided with a continuous rotary valve 22 having a diametrical passage 22a to rapidly and continuously open and close the valve.

With the above configuration, as the orbiting scroll l rotates eccentrically as the main shaft (not shown) rotates,
The contact point between the spiral members 1a and 2a moves from the periphery to the center, and as a result, fluid is sucked in from the suction port 3, and internal compression is performed while the fluid moves toward the discharge port 4 at the center of the fixed scroll. Pressure increases. When the operating pressure Pd is higher than the pressure P2 generated by the unique built-in internal compression ratio, when the rotary valve 22 of the bypass pipe 21 continuously rotates, a part of the fluid discharged from the discharge port 4 is When the continuous rotary valve 22 of the bypass pipe is in the open state, it is discharged to the low pressure Pa section. At this time, the operation is performed at points ■→■→■ in FIG.

Further, in the closed state, the flow to the bypass pipe 21 is stopped and the fluid flows to the main pipe 6. At this time, it is operated at points ■→■→■ in the same figure.

Comparison of the discharge temperature Td of the conventional scroll compressor without the bypass pipe described above and the discharge temperature Td of the scroll compressor according to the present invention in which a high-speed cycle opening/closing device (rotary valve 22) is installed in the bypass pipe on the discharge side. Then, for example, 1
When the opening and closing times are the same per cycle and the switching device is operated in the following state (2), the discharge temperature in the open or closed state will be as shown in Table 1 below: (Table 1), the average discharge temperature Td is 140'C and 40'C.
The average temperature is approximately 90°C.

Therefore, it can be seen that the discharge temperature Tdζ140'C is lower than that of the conventional scroll compressor (FIG. 2).

The opening area of the opening/closing device of the present invention, the passage cross-sectional area of the diametrical passage 22a of the rotary valve 22 in the above embodiment, or the opening/closing speed, the rotation speed of the rotary valve 22 in the above embodiment, or the above opening area and opening/closing speed. By changing both, the discharge temperature of the compressor can be adjusted.

In the above-described embodiment, the structure in which the continuous opening/closing device was constructed by the rotary valve 22 was explained, but the bypass pipe 2
A sliding valve body having a passage such as a groove parallel to the axial direction of
It is also possible to configure the valve body as a reciprocating type valve that reciprocates in a direction perpendicular to the bypass pipe, and it is also possible to configure the valve body to rotate and oscillate.

〔Effect of the invention〕

As explained above, according to the present invention, a bypass pipe communicating with a pressure lower than the operating pressure or atmospheric pressure is provided outside the main pipe at the discharge port of the compressor, and a continuous rotation or reciprocating By installing a high-speed cycle opening/closing device, the effect of pressure drop in the main pipe is reduced, the discharge temperature of the compressor is lowered, and the
It is possible to reduce the influence of heat on the shaft portion, etc., and extend the mechanical life.

Furthermore, the discharge temperature of the compressor can be adjusted by changing the opening area or the opening/closing speed of the continuous opening/closing bag π provided in the bypass pipe, or by changing both of them.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main part showing an embodiment of the present invention, Fig. 2 is a sectional view of the main part showing a conventional example, and Fig. 3 is a PV illustrating the operation.
It is a line diagram. 1... Orbiting scroll, 2... Fixed scroll, 3
... Suction port, 4... Discharge port, 5... Check valve, 6... Main pipe, 7... Air tank,
DESCRIPTION OF SYMBOLS 10... Bearing and rotation prevention mechanism, 21... Bypass pipe, 22... Continuous rotation valve, Pd... Operating pressure, Td... Discharge temperature.

Claims (3)

[Claims] 1. A scroll compressor is a compression device that compresses and sucks gases such as air, gas, and water vapor, and operates at a pressure higher than the pressure generated by the compressor's built-in internal compression ratio (including cases where the internal compression ratio is 1.0). In addition to the main pipe, a bypass pipe communicating with a pressure lower than the operating pressure or atmospheric pressure is provided at the discharge port of the compressor, and within the bypass pipe,
A scroll compressor equipped with a bypass pipe on the discharge side, characterized in that a continuous opening/closing device using rotation or reciprocating motion is provided to minimize the influence of pressure drop in the main pipe and lower the discharge temperature. 2. 2. The scroll having a bypass pipe on the discharge side according to claim 1, wherein the discharge temperature of the compressor can be adjusted by changing the area of the opening of the continuous opening/closing device provided in the bypass pipe. compressor. 3. 2. The scroll compressor with a bypass pipe on the discharge side according to claim 1, wherein the discharge temperature of the compressor can be adjusted by changing the opening/closing speed of a continuous opening/closing device provided in the bypass pipe. .