JPH07174097A - Centrifugal compressor - Google Patents

Abstract

PURPOSE:To effectively discharge the solid/gas mixture interposed in the space between the casing of a centrifugal compressor and the cover of an impeller. CONSTITUTION:A space 7 formed between the casing 2 of a centrifugal compressor 1 and the cover 3c of an impeller 3 and an inflow pipe 4 for the inflow of the solid/gas mixture into a centrifugal compressor 1 are allowed to communicate with each other by a suction pipe 8, the inside of the suction pipe 8 is made negative by the flow speed of the solid/gas mixture which flows in the inflow pipe 4, and the solid/gas mixture which intrudes into the space 7, passing between the casing 2 and the impeller 3 is discharged into the inflow pipe 4 through the suction pipe 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a centrifugal compressor used for compressing a solid-air mixture, and more specifically, a powder in a solid-air mixture obtained by mixing powder with gas. The present invention relates to a centrifugal compressor that effectively prevents a body from adhering to the impeller cover.

[0002]

2. Description of the Related Art In a chemical process, a solid-air mixture obtained by mixing powder with gas may be compressed by a centrifugal compressor. A typical example of such a centrifugal compressor will be described with reference to FIG. 3 which is a cross-sectional view of a main part thereof and FIG. 4 which is an enlarged view of part A of FIG. A casing 52 having a suction port 52a to which an inflow pipe 54 for inflowing an air-fuel mixture is connected and having a spiral flow path 52b, a cover 53c on the suction port 52a side, and a hub 5 on the non-suction port 52a side.
An impeller 53 including 3b and a plurality of curved and twisted blades 53a between them is internally provided.
The impeller 53 is configured to be rotated by a drive shaft 56 that penetrates a casing cover 55 that closes an opening 52c provided on the side opposite to the suction port 52a of the casing 52.

A space 57 is formed between the inside of the casing 52 and the cover 53c of the impeller 53, and the casing 52 is provided with a passage 52d communicating from the space 57 to the outside. A buffer gas supply pipe 58 for supplying a high-pressure buffer gas communicates with the passage 52d. The reason why the buffer gas supply pipe 58 is made to communicate with the passage 52d is to eliminate the problems described later relating to the centrifugal compressor.

That is, a part of the solid-gas mixture that is compressed by the rotation of the impeller 53 and flows into the spiral flow path 52b is a space 57.
The powder, which is an inclusion in the solid-air mixture that has entered the inside, adheres to the side surface of the cover 53c of the impeller 53. Then, the center of gravity of the impeller 53 is unbalanced and the impeller 53 vibrates, which makes it impossible to continue the operation of the centrifugal compressor 51 and may possibly damage the centrifugal compressor 51. Therefore, from the buffer gas supply pipe 58 to the space 5
This is because a high-pressure buffer gas is supplied into the space 7 to prevent the solid-air mixture from entering the space 57.

[0005]

As described above, if high-pressure buffer gas is supplied from the buffer gas supply pipe into the space, it is effective to prevent the powder from adhering to the impeller cover. However, since the buffer gas enters the spiral flow passage from between the impeller and the labyrinth packing, if the amount of the buffer gas entering increases, the properties of the solid-gas mixture handled will change and adversely affect the process. , Unable to supply buffer gas indefinitely. However, once the solid-air mixture enters the space, the powder cannot be reliably removed from the space, so a large amount of buffer gas must be supplied, which has a negative effect on the process. There is a problem to be solved that the operating cost of the centrifugal compressor related to the supply cost of the buffer gas increases.

Therefore, it is an object of the present invention to provide a centrifugal compressor capable of reliably discharging powder from a space without supplying a buffer gas into the space.

[0007]

According to the present invention, if a means for discharging inclusions existing in a space to the outside of the casing is taken, it is not necessary to supply a buffer gas that adversely affects the process. Therefore, the characteristic of the main means adopted by the centrifugal compressor according to the present invention is that the impeller 3 having the blade 3a between the hub 3b and the cover 3c is internally provided in the casing 2. In a centrifugal compressor for sucking and compressing a solid-air mixture from a suction port 2a provided in the casing 2, the casing 2 and the cover 3c of the impeller 3 are attached to the casing 2.
It is where one end side of a suction pipe 8 for sucking inclusions intervening in the space 7 formed between and is connected.

[0008]

According to the centrifugal compressor of the present invention, the casing 2 of the centrifugal compressor has a suction pipe for sucking inclusions existing in the space 7 formed between the casing 2 and the cover 3c of the impeller 3. Since one end side of 8 is connected, the inclusions existing in the space 7 can be discharged by the suction pipe 8.

[0009]

EXAMPLE A centrifugal compressor according to an example of the present invention will be described below.
It will be described with reference to FIG. 1 which is a sectional view of the main part. However, the main configuration of the centrifugal compressor according to the present embodiment is the same as the conventional one, and the different point is the difference in the powder discharging means. Therefore, only the difference will be described.

The casing 2 of the centrifugal compressor 1 is provided with a through hole 2d which communicates with a space 7 formed between the inside of the casing 2 and the cover 3c of the impeller 3, and this through hole 2d. Is connected to one end of the suction tube 8. The other end of the suction pipe 8 is connected to the suction port 2a of the casing 2 and is connected to an inflow pipe 4 for supplying a solid-air mixture, and the space 7 and the inflow pipe 4 are connected to each other by the suction pipe 8 Are configured to communicate with each other. The other end of the suction pipe 8 may be connected to the upstream side of the suction port 2a, and the connecting position is not limited to the inflow pipe 4.

The mode of operation of the centrifugal compressor 1 having the above structure will be described below. When the impeller 3 is rotated by the drive shaft 6, the solid-gas mixture is sucked from the inflow pipe 4 and the sucked solid-gas mixture is sucked. The air is compressed by the rotating impeller 3 and flows into a spiral flow passage (not shown) of the casing 2. However, a part of the compressed solid-air mixture is a gap between the impeller 3 and the labyrinth packing S. And penetrates into the space 7 formed between the inside of the casing 2 and the cover 3c of the impeller 3. However, the inside of the suction pipe 8 has a negative pressure due to the flow velocity of the solid-gas mixture flowing through the inflow pipe 4.
Therefore, the solid-air mixture that is an inclusion that enters the space 7 is sucked by the suction pipe 8 and discharged into the inflow pipe 4.

As described above, since the solid-air mixture that continues to enter the space 7 is continuously sucked by the suction pipe 8 and continuously discharged into the inflow pipe 4, high-pressure buffer gas is supplied into the space 7 as in the conventional case. It is not necessary to supply the gas, the cause of adversely affecting the process is eliminated, and the cost for operating the centrifugal compressor 1 can be reduced. In addition, since the powder does not stay in the space 7 for a long time, the impeller 3 does not vibrate, and further, the progress of wear of the impeller seal on the suction port 2a side of the impeller 3 is delayed and the impeller seal is not As a result of the long life, the parts replacement interval becomes long, and the effect that the repair cost of the centrifugal compressor 1 can be reduced is also derived.

Next, a centrifugal compressor according to another embodiment of the present invention will be described with reference to FIG. 2 which is a sectional view of a main part thereof. A gas supply pipe in which an ejector 9a is interposed and a buffer gas is flown. 9 is connected to the inflow pipe 4, one end side is connected to the casing 2, the other end side is connected to the ejector 9a, and the suction pipe 8 connects the space 7 and the ejector 9a. It is what Therefore, when the buffer gas is supplied to the gas supply pipe 9, the solid-gas mixture flowing into the space 7 is sucked toward the ejector 9a side through the suction pipe 8 by the action of the ejector 9a, and the gas supply pipe 9 Since the solid-gas mixture flows into the inflow pipe 4 together with the flowing buffer gas, this embodiment has the same effect as the above embodiment.

In this embodiment, it is necessary to supply the buffer gas from the gas supply pipe 9 as in the conventional case, but the supply destination is not the high pressure side as in the conventional case, but the low pressure side inflow. Since it is the pipe 4, it is not necessary to make the buffer gas have a high pressure as in the conventional case, and the supply amount of the buffer gas can be much smaller than in the conventional case. Can be significantly reduced.

[0015]

As described above, according to the centrifugal compressor of the present invention, it is formed between the casing and the impeller cover without the need for supplying a high-pressure buffer gas as in the conventional case. Since the inclusions existing in the space can be discharged by the suction pipe, it has a great effect on eliminating the adverse effect on the process and reducing the operating cost of the centrifugal compressor.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a centrifugal compressor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a centrifugal compressor according to another embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a conventional typical centrifugal compressor.

FIG. 4 is an enlarged view of part A of FIG.

[Explanation of symbols]

1 ... Centrifugal compressor, 2 ... Casing, 2a ... Suction port, 2d
... through hole, 3 ... impeller, 3a ... blade, 3b ... hub, 3c ... cover, 4 ... inflow pipe, 5 ... casing cover, 6 ... drive shaft, 7 ... space, 8 ... suction pipe, 9 ... gas supply pipe, 9a ... Ejector, S ... Labyrinth packing.

Claims (1)

[Claims] 1. A centrifugal compression in which an impeller 3 having a blade 3a between a hub 3b and a cover 3c is provided in a casing 2, and a solid-air mixture is sucked and compressed from a suction port 2a provided in the casing 2. In the machine, the casing 2 is connected to one end side of a suction pipe 8 for sucking inclusions existing in a space 7 formed between the casing 2 and the cover 3c of the impeller 3. Machine.