JP2544777B2 - Scroll compressor with a bypass pipe on the discharge side - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a scroll device (spiral compressor) used for compressing and sucking gas such as air, gas and water vapor, and more particularly, to a scroll device of the scroll device. The present invention relates to scroll compressors that operate at pressures higher than those produced by the inherent built-in internal compression ratio.

[Conventional technology]

As shown in FIG. 2, the conventional scroll device has an orbiting scroll (spiral) 1 having one spiral member 1a wound in a spiral shape and the same scroll member 1a having the same shape formed so as to overlap with the spiral member 1a. A fixed scroll 2 that also functions as an upper casing having a spiral member 2a is provided so as to be eccentric (eccentric amount e) so as to face each other. When used as a compressor, the fixed scroll 2 has an outer peripheral portion. A suction port 3 for sucking the fluid is also provided, and a discharge port 4 is similarly provided at the center. The discharge port 4 is connected to an air tank 7 via a main pipe 6 provided with a check valve 5 on the way, and is sent out from the air tank 7 at an operating pressure Pd.

On the other hand, the orbiting scroll 1 is supported by bearings 8 and is driven via a shaft 9 corresponding to a rotor which is eccentric by an eccentric amount (orbiting radius) e and is rotated in the arrow direction. The shaft 9 is provided with a balance weight (not shown). In the figure, 10 is a thrust bearing and a rotation preventing 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, in which P _{1 is an} inlet pressure, P _{2 is a} discharge output (a built-in internal compression unique to the compressor. the pressure caused by the ratio), V _1: inlet volume, V _2: outlet volume (volume determined by the built-in volume ratio), Pd: an operating pressure (operating discharge pressure).

And the built-in internal compression ratio (P ₂ / P ₁ ) is defined by the following theoretical formula.

(P ₂ / P ₁ ) = (V ₁ / V ₂ ) ⁿ where n: polytropic index (V ₁ / V ₂ ): built-in volume ratio However, the operating pressure Pd delivered from the air tank 7
Is the pressure P ₂ caused by the built-in internal compression ratio peculiar to the compressor.
If it is higher, it will be operated at →→ points.

[Problems to be Solved by the Invention]

As described above, when the conventional scroll compressor is operated at a pressure Pd higher than the pressure P ₂ generated by the built-in internal compression ratio (P ₂ / P ₁ ) specific to the compressor, for example, The discharge temperature Td is about 140 ° C.

As described above, when the compressor is operated in a state where the discharge side has no pressure lower than the operating pressure Pd or a bypass pipe leading to the atmospheric pressure, the compressor discharge temperature Td becomes high due to the heat of gas compression, and the orbiting scroll 1 There has been a problem that heat is exerted on the back portion (lower portion in the figure), the bearing 8 and the rotor (shaft) portion 9 to cause a strength problem and shorten the mechanical life.

It is an object of the present invention to provide a scroll compressor that reduces the influence of pressure drop in the main pipe and lowers the discharge temperature of the compressor to prolong the mechanical life.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a discharge port of a compressor in a scroll compressor (including an internal compression ratio of 1.0) which operates at a pressure higher than a pressure generated by a built-in internal compression ratio inherent to the compressor. By connecting a bypass pipe communicating with a pressure lower than the operating pressure or atmospheric pressure to the outside of the main pipe, a continuous opening / closing device by rotating or reciprocating motion is provided in the bypass pipe to minimize the influence of the pressure drop in the main pipe. It is characterized in that the discharge temperature is reduced as well as the discharge temperature.

By changing the area of the opening of the continuous opening / closing device provided in the bypass pipe, the discharge temperature of the compressor can be adjusted, and the opening / closing speed of the continuous opening / closing device can be changed. The discharge temperature can be adjusted.

[Work]

Since the present invention is configured as described above, during operation,
Compressible fluid such as air, gas, water vapor, etc. sucked from the suction port causes the spiral member of the orbiting scroll to move around the contact point (position) with respect to the spiral member of the fixed scroll due to the revolving (orbiting) motion of the orbiting scroll. As it turns while moving to the center more sequentially, it is pressed and transferred to the center, and is discharged to the outside from the discharge port in the center, which is the same as the conventional one.

However, in the present invention, during operation, the fluid flows through the bypass pipe when the switchgear in the bypass pipe is opened, and when closed, the flow to the bypass pipe is stopped and the fluid flows to the main pipe. Therefore, the discharge pressure of the compressor alternates between the operating pressure, that is, the pressure (operating pressure) higher than the pressure generated by the built-in internal compression ratio peculiar to the compressor and the pressure lower than the operating pressure or the atmospheric pressure. The discharge temperature in the open state is low,
Further, the discharge temperature in the closed state becomes high and the average discharge temperature becomes low.

Also, since the opening and closing of the bypass pipe is repeated alternately in a cycle of a certain level or more, the influence of the pressure drop in the main pipe is reduced, and the discharge temperature of the compressor can be lowered as described above. The mechanical life can be extended.

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

When the continuous switchgear provided in the bypass pipe is opened and air is blown into the atmosphere, the operation is performed at points →→ in FIG.

〔Example〕

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

FIG. 1 is a sectional view of a main part of a scroll compressor according to an embodiment of the present invention, in which the same reference numerals as those shown in FIG. 2 denote the same or similar parts.

In the figure, a spiral member 1a on the upper surface of the orbiting scroll 1
Is installed eccentrically by the orbiting radius e on the spiral member 2a on the inner surface of the upper portion of the fixed scroll 2 which also serves as the upper casing. The contact point of 2a moves from the peripheral part to the central part, and accordingly, the fluid is sucked from the suction port 3,
Discharge is performed from a discharge port 4 at a central portion. The discharge port 4 is connected to an air tank 7 via a main pipe 6 provided with a check valve 5, and has an operating pressure Pd from the air tank 7. The point that is sent out by the conventional one (Fig. 2)
There is no change.

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

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

The orbiting scroll 1 is configured as described above.
Is eccentrically rotated as the main shaft (not shown) rotates, the contact points of the spiral members 1a and 2a move from the peripheral portion to the central portion, and accordingly, the fluid is sucked through the suction port 3 and discharged at the central portion of the fixed scroll. While moving toward the outlet 4, internal compression is performed and the pressure is increased. When the operating pressure Pd is operated at a high pressure equal to or higher than the pressure P ₂ generated by the 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 When the continuous rotary valve 22 of the bypass pipe is in the open state, the low pressure Pa is discharged. At this time, the operation is performed at the →→ point in Fig. 3.

Further, in the closed state, the flow to the bypass pipe 21 is stopped and the fluid flows to the main pipe 6. In this case, the operation is made at the →→ point in the figure.

The discharge temperature Td of the conventional scroll compressor not having the bypass pipe described above is compared with 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, the time of opening and closing is the same per cycle, and the state of the following (2),
That is, In the case of, when the switchgear is operated, the discharge temperature in the open or closed state is shown in Table 1 below. The average discharge temperature Td is about 90 ° C., which is the average value of 140 ° C. and 40 ° C.

Therefore, it is understood that the discharge temperature Td of the conventional scroll compressor (Fig. 2) becomes lower than 140 ° C.

The opening area of the opening / closing device of the present invention, the passage 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 opening area and the opening / closing speed The discharge temperature of the compressor can be adjusted by changing both of them.

In the embodiment described above, the structure in which the continuous opening / closing device is constituted by the rotary valve 22 has been described.
It is also possible to configure a sliding valve body having a passage such as a groove parallel to the axial direction of (1) as a reciprocating valve which is configured to reciprocate in a direction orthogonal to the bypass pipe. It is also possible to make a rotational oscillating motion.

〔The invention's effect〕

As described 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 the bypass pipe continuously rotates or reciprocates. By providing a high-speed cycle switchgear that reduces the influence of pressure drop in the main pipe, reduces the discharge temperature of the compressor, reduces the influence of heat on the orbiting scroll, bearings and rotor (shaft), The mechanical life can be extended.

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

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention, FIG. 2 is a sectional view of an essential part showing a conventional example, and FIG. 3 is a PV diagram for explaining the operation. 1 ... Orbiting scroll, 2 ... Fixed scroll, 3 ... Suction port, 4 ... Discharge port, 5 ... Check valve, 6 ... Main pipe, 7 ... Air tank, 10 ... Bearing and rotation prevention mechanism , 21 …… Bypass pipe, 22 …… Continuous rotary valve, Pd …… Operating pressure, Td …… Discharge temperature.

Claims (3)

(57) [Claims] 1. A scroll compressor which is a compressor for compressing and sucking gas such as air, gas and water vapor and which operates at a pressure higher than a pressure generated by a built-in internal compression ratio peculiar to the compressor. In addition, 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 by rotation or reciprocating motion is provided in the bypass pipe. hand,
A scroll compressor provided with a bypass pipe on the discharge side, which is characterized by minimizing the influence of the pressure drop in the main pipe and reducing the discharge temperature. 2. The bypass 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. Scroll compressor with pipe. 3. A bypass pipe on the discharge side according to claim 1, wherein the opening / closing speed of a continuous opening / closing device provided in the bypass pipe is changed so that the discharge temperature of the compressor can be adjusted. Equipped scroll compressor.