JPH11303796A - Casing for fluid machine such as centrifugal pump or centrifugal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increase of head with a large flow amount and axial power of a motor while facilitating reception of fluid in a scroll chamber irrespective of spacing from a fluid discharge port in a casing in which the control chamber and an impeller are concentrically and cylindrically formed with even diameters by preventing the occurrence of the recirculation flow, and downsize the device by reducing an area of the casing perpendicular to a main shaft. SOLUTION: A tongue 8 projected radially inward is formed on an immediately downstream position of a discharge port 7 in a rotational direction R of an open impeller 2 in a scroll chamber 6. A bottom 6A is gradually decended downward from the tongue 8 to the position P on a downstream side thereof by 135 degrees in the rotational direction R of the open impeller 2, in order to gradually increase axial length of the scroll chamber 6. A sectional area of the scroll chamber 6 is thus gradually increased from the tongue 8 to the P position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casing of a fluid machine such as a centrifugal pump or a centrifugal blower for discharging a fluid by utilizing the centrifugal force of the fluid generated by rotation of an impeller.

[0002]

2. Description of the Related Art Among centrifugal pumps that discharge a fluid by utilizing the centrifugal force of a fluid generated by rotation of an impeller, there is a vortex pump that functions as a low-head / large-flow pump. In the vortex pump, as shown in FIGS. 5 and 6, an open impeller 2 fixed to the tip of a main shaft 1 is rotatably housed inside a casing 3, and the open impeller 2 is driven by a motor (not shown). It rotates with the main shaft 1. The casing 3 has a suction port 4 which faces the center of the open impeller 2 and is opened with an axial gap L therebetween.
Is provided. Therefore, the water is open impeller 2
, The air is sucked into the center of the open impeller 2 from the suction port 4, rotates with the open impeller 2, and is discharged from the entire circumference of the open impeller 2 by centrifugal force. Water discharged from the entire circumference of the open impeller 2 is received by the swirling chamber 6 and guided to the discharge port 7.

In the vortex pump, it is required that water discharged from the entire periphery of the open impeller 2 is received by the swirling chamber 6 and then rapidly guided to the discharge port 7 at a uniform flow rate in the circumferential direction. However, although the amount of water received in the swirl chamber 6 gradually increases as approaching the discharge port 7, the swirl chamber 6 is formed in a cylindrical shape concentric with the open impeller 2 and having a uniform inner diameter. Since the cross-sectional area is uniform from a portion far from the discharge port 7 to the discharge port 7, the reception in the swirl chamber 6 becomes difficult as the discharge port 7 is approached, and the open impeller 2 becomes closer as the discharge port 7 is approached. Is discharged into the gap L without being received by the swirling chamber 6,
This is a factor for generating the recirculating flow S that turns at high speed in the gap L. Due to the generation of the recirculation flow S, a problem arises in that the head at a large flow rate and the shaft power of the prime mover are increased. Further, there is a disadvantage that the area of the casing 3 orthogonal to the main shaft 1 is increased.

On the other hand, among centrifugal pumps that discharge fluid using the centrifugal force of fluid generated by rotation of an impeller, there is a centrifugal pump that functions as a relatively low-head / large-flow pump. In the centrifugal pump, as shown in FIGS. 7 and 8, a closed impeller 2 fixed to a tip end portion of a main shaft 1 is rotatably housed in a casing 3, and the closed impeller 2 is driven by a motor (not shown). Spindle 1
Rotates with. The casing 3 is provided with a suction port 4 that opens to face the center of the closed impeller 2. Therefore, the water is sucked into the central portion of the closed impeller 2 from the suction port 4 by the rotation of the closed impeller 2, rotates together with the closed impeller 2, and is discharged from the entire circumference of the closed impeller 2 by centrifugal force. Water discharged from the entire circumference of the closed impeller 2 is received by the swirl chamber 6 and guided to the discharge port 7.

In a centrifugal pump, a closed impeller 2
It is required that after the water discharged from the entire circumference is received by the vortex chamber 6, the water is rapidly guided to the discharge port 7 at a uniform flow rate in the circumferential direction. Therefore, by forming the spiral chamber 6 in a volute shape eccentric to the closed impeller 2, the spiral chamber 6 is formed.
Is gradually increased in the diametrical direction as it approaches the discharge port 7 from the winding start point O, and the amount of water received gradually increases as it approaches the discharge port 7. However, the conventional centrifugal pump has a disadvantage that the area of the casing 3 orthogonal to the main shaft 1 is increased.

[0006]

That is, in a casing of a conventional fluid machine such as a centrifugal pump or a centrifugal blower, in which the swirl chamber is formed concentrically with the impeller and has a cylindrical shape with a uniform inner diameter, As it approaches the discharge port, it becomes difficult to receive the fluid in the swirl chamber, and as it approaches the fluid discharge port, the fluid discharged from the impeller flows into the gap without being received in the swirl chamber and recirculates at high speed in this gap. This causes the flow to occur, and raises the problem of raising the head at large flow rates and increasing the shaft power of the prime mover.
There is a disadvantage that the area of the casing orthogonal to the main shaft becomes large. On the other hand, in a casing in which the spiral chamber is formed in a volute shape eccentric to the impeller, the sectional area of the spiral chamber gradually increases in the diameter direction as approaching the fluid discharge port from the winding start point, and approaches the fluid discharge port. As the amount of water received gradually increases,
There is a disadvantage that the area of the casing orthogonal to the main shaft becomes large. Therefore, the present invention relates to a casing in which a swirl chamber is formed in a cylindrical shape concentric with an impeller and having a uniform inner diameter.
Regardless of the distance to the fluid discharge port, it is easy to receive fluid in the swirl chamber to prevent recirculation flow, and to suppress the head at a large flow rate and the increase in shaft power of the prime mover It is a first object of the present invention to provide a casing of a fluid machine such as a centrifugal pump or a centrifugal blower, which can be made compact while reducing the area of the casing perpendicular to the main shaft and which can be easily manufactured. . On the other hand, for a casing in which the spiral chamber is formed in a volute shape eccentric to the impeller, the area of the casing orthogonal to the main shaft can be reduced to make the casing compact, and a centrifugal pump or a centrifugal blower that is easy to manufacture is provided. It is a second object of the present invention to provide a casing of a fluid machine such as the above.

[0007]

In order to achieve the first object, a casing of a fluid machine such as a centrifugal pump or a centrifugal blower according to the first aspect of the present invention rotatably accommodates an impeller. And a fluid suction port that opens to face the center of the impeller, and is rotated from the fluid suction port into the center by the rotation of the impeller, and then rotates with the impeller to rotate around the impeller by centrifugal force. Fluid, such as a centrifugal pump or a centrifugal blower, which has a swirl chamber for receiving fluid discharged from the fluid guide and guiding the fluid to a fluid discharge port, wherein the swirl chamber is concentric with the impeller and formed in a cylindrical shape having a uniform inner diameter. In the casing of the machine, the axial length of the swirl chamber is gradually increased from a position far from the fluid discharge port in the rotation direction of the impeller toward the fluid discharge port, so that a cross-sectional area of the swirl chamber is increased. For fluid outlet Gradually by increasing as from the stomach located closer to the fluid discharge port, it is characterized in that the flow rate of the whirling chamber is configured to be uniform in the circumferential direction.

In order to achieve the second object, a casing of a fluid machine such as a centrifugal pump or a centrifugal blower according to the second aspect of the present invention accommodates an impeller in a freely rotatable manner and a center of the impeller. A fluid suction port that opens to face the portion, and the fluid that is discharged from the entire circumference of the impeller by centrifugal force after being sucked into the central portion from the fluid suction port by rotation of the impeller and rotating together with the impeller. A casing of a fluid machine, such as a centrifugal pump or a centrifugal blower, which is provided with a spiral chamber for receiving and guiding the fluid to the fluid discharge port, wherein the spiral chamber is formed in a volute shape eccentric to the impeller; The length of the spiral direction is gradually increased from the winding start point of the spiral chamber to the fluid discharge port, and the sectional area of the spiral chamber gradually increases from the winding start point to the fluid discharge port. By, is characterized by being configured as a flow rate of vortex chamber is uniform in the circumferential direction.

According to the first aspect of the present invention, the axial length of the swirl chamber concentric with the impeller is gradually increased from a portion far from the fluid discharge port toward the fluid discharge port. Since the cross-sectional area of the swirl chamber is gradually increased from the portion far from the fluid discharge port to the fluid discharge port, even if the amount of fluid received in the swirl chamber gradually increases as approaching the discharge port, it can be easily received. Can be. Further, the area orthogonal to the main shaft can be reduced as compared with a conventional casing having the same discharge amount.

According to the second aspect of the present invention, the axial length of the vortex chamber corresponding to the eccentricity of the impeller gradually increases as approaching the fluid discharge port from the winding start point of the vortex chamber. Then, since the cross-sectional area of the spiral chamber is gradually increased as approaching the fluid discharge port from the winding start point, compared to a conventional casing having the same discharge amount, the increase in the diameter direction is suppressed, The area orthogonal to the main axis can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a casing of a fluid machine such as a centrifugal pump or a centrifugal blower according to the present invention will be described below with reference to the drawings. 1 and 2, an open impeller 2 fixed to the tip of a main shaft 1 is rotatably housed in a casing 3, and the open impeller 2 is moved together with the main shaft 1 by a motor (not shown). Rotate. The casing 3 is provided with a suction port 4 that faces the center of the open impeller 2 and that opens through a gap L in the axial direction. Therefore, the water is sucked into the center of the open impeller 2 from the suction port 4 by the rotation of the open impeller 2, rotates together with the open impeller 2, and is discharged from the entire circumference of the open impeller 2 by centrifugal force. Water discharged from the entire circumference of the open impeller 2 is received by a swirl chamber 6 which is concentric with the open impeller 2 and has a uniform inner diameter and is guided to a discharge port 7.

At a position farthest from the discharge port 7 in the swirl chamber 6, that is, at a position immediately downstream of the discharge port 7 in the rotation direction R of the open impeller 2 in the swirl chamber 6, a tongue 8 projecting inward in the radial direction is provided. In order to gradually increase the axial length of the swirling chamber 6 from the tongue 8 to the position P about 135 ° downstream in the rotation direction R of the open impeller 2 from the tongue 8, the bottom surface 6A is lowered. By inclining at a gradient, the sectional area of the swirling chamber 6 is gradually increased from the tongue 8 to the P position.

With such a configuration, the water sucked into the central portion of the open impeller 2 from the suction port 4 by the rotation of the open impeller 2 rotates together with the open impeller 2 and is centrifugally driven. 2, the amount of water received in the swirl chamber 6 gradually increases as approaching the discharge port 7, and the swirl chamber 6 is concentric with the open impeller 2 and has a uniform inner diameter. Even if it is formed in a shape, the axial length of the swirling chamber 6 is gradually increased from the tongue 8 provided immediately downstream of the discharge port 7 to the P position, and the cross-sectional area of the swirling chamber 6 is increased. Since it is gradually increased from the tongue portion 8 to the P position, it can be easily received by the swirling chamber 6. For this reason, it is possible to prevent the water discharged from the entire circumference of the open impeller 2 from flowing into the gap L without being received by the swirling chamber 6 and generating the recirculating flow S (see FIG. 6) that rotates at high speed. It is possible to suppress the head at a large flow rate and the increase in the shaft power of the prime mover. Further, as compared with the conventional casing 3 having the same discharge amount, the area orthogonal to the main shaft 1 can be reduced, the size can be reduced, and the casing 3 which can be easily manufactured can be provided.

Next, an embodiment of a casing of a fluid machine such as a centrifugal pump or a centrifugal blower according to the present invention will be described with reference to the drawings. 3 and 4, in the centrifugal pump, a closed impeller 2 fixed to a tip end portion of a main shaft 1 is rotatably housed inside a casing 3, and the closed impeller 2 is moved together with the main shaft 1 by a motor (not shown). Rotate. The casing 3 is provided with a suction port 4 that opens to face the center of the closed impeller 2. Therefore, the water is sucked into the central portion of the closed impeller 2 from the suction port 4 by the rotation of the closed impeller 2, rotates together with the closed impeller 2, and is discharged from the entire circumference of the closed impeller 2 by centrifugal force. Water discharged from the entire circumference of the closed impeller 2 is received by the swirl chamber 6 and guided to the discharge port 7.

In the centrifugal pump, the closed impeller 2
It is required that after the water discharged from the entire circumference is received by the vortex chamber 6, the water is rapidly guided to the discharge port 7 at a uniform flow rate in the circumferential direction. Therefore, by forming the spiral chamber 6 in a volute shape eccentric to the closed impeller 2, the spiral chamber 6 is formed.
Is gradually increased in the diametrical direction as it approaches the discharge port 7 from the winding start point O, and the amount of water received gradually increases as it approaches the discharge port 7.

On the other hand, a tongue 8 projecting radially inward is provided at the winding start point O in the spiral winding chamber 6.
13 from the tongue 8 in the rotation direction R of the closed impeller 2.
In order to gradually increase the axial length of the swirling chamber 6 toward the P position on the downstream side of about 5 °, the bottom surface 6A is inclined with a downward gradient so that the cross-sectional area of the swirling chamber 6 is reduced by the tongue. 8 to the P position.

As described above, the axial length of the spiral chamber 6 is gradually increased from the tongue 8 at the winding start point O of the spiral chamber 6 to the position P, so that the cross-sectional area of the spiral chamber 6 is increased. Since it gradually increases from the tongue portion 8 of the winding start point O to the position P, the cross-sectional area of the spiral chamber 6 gradually increases in the diameter direction from the winding start point O toward the discharge port 7. As a result, the amount of water received is gradually increased as approaching the discharge port 7, and the water discharged from the entire periphery of the closed impeller 2 is received by the swirl chamber 6, and then quickly at a uniform flow rate in the circumferential direction. Satisfies the requirement for leading to the discharge port 7.
In addition, as compared with a conventional casing having the same discharge rate, an increase in the diameter of the spiral chamber 6 in the diametrical direction can be suppressed, the area orthogonal to the main shaft 1 can be reduced, and compactness can be achieved, and production is easy. A simple casing 3 can be provided.

In the embodiment according to the first and second aspects of the present invention, the P position about 135 ° downstream in the rotational direction R of the impeller 2 from the tongue 8 projecting inward in the radial direction. In order to gradually increase the axial length of the swirling chamber 6, the bottom surface 6A is inclined with a downward gradient,
Although the cross-sectional area of the swirling chamber 6 is gradually increased, the end point of the bottom surface 6A inclined at a downward slope is not limited to the P position, but in the rotation direction R of the impeller 2 more than the P position. It may be slightly upstream or near the entrance of the discharge port 7.

In the first aspect of the invention, a vortex pump for pumping water by centrifugal force is described. In the second aspect of the invention, a centrifugal pump for pumping water by centrifugal force is described. The invention described in claim 2 is not limited only to the above-described embodiment, but can be applied to, for example, a low-head / high-flow mixed-flow pump that pumps water by both actions of centrifugal force and lift. Also,
The present invention can be applied to a fluid machine such as a centrifugal blower such as a multi-blade blower, a radial blower, and a turbo blower.

Further, since this kind of casing 3 is simple in structure and production, it is particularly advantageous when constructing a large concrete casing used in a drainage pump station or the like or producing a relatively large can-made casing. Yes, construction and manufacturing costs can be significantly reduced.

[0021]

As described above, the casing of the fluid machine such as the centrifugal pump or the centrifugal blower according to the first aspect of the present invention has a structure in which the axial length of the swirl chamber concentric with the impeller is determined by the fluid discharge. Since the cross-sectional area of the swirl chamber is gradually increased from the portion far from the outlet to the fluid discharge port, and gradually increased from the portion far from the fluid discharge port to the fluid discharge port, the fluid in the swirl chamber is increased. Can be easily received even if the received amount gradually increases as approaching the discharge port. For this reason, it is possible to prevent the water discharged from the entire circumference of the impeller from flowing into the gap without being received by the swirling chamber, thereby preventing the occurrence of a recirculating flow that rotates at a high speed, thereby increasing the head at a large flow rate and the shaft power of the prime mover. The increase can be suppressed. Further, as compared with a conventional casing having the same discharge amount, an area orthogonal to the main shaft can be reduced, the size can be reduced, and a casing that can be easily manufactured can be provided.

The casing of a fluid machine such as a centrifugal pump or a centrifugal blower according to the second aspect of the present invention is configured such that the axial length of the spiral chamber corresponding to the impeller is eccentric to the impeller. A conventional casing having the same discharge amount because the cross-sectional area of the vortex chamber is gradually increased as approaching the fluid discharge port from the start point and gradually increasing as approaching the fluid discharge port from the winding start point. As compared with the case, it is possible to suppress an increase in the diameter direction, reduce the area orthogonal to the main shaft, achieve compactness, and provide a casing that is easy to manufacture.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of the invention described in claim 1;

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a plan view showing an embodiment of the invention described in claim 2;

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a plan view of a conventional example corresponding to the invention described in claim 1;

FIG. 6 is a sectional view taken along line CC of FIG. 5;

FIG. 7 is a plan view of a conventional example corresponding to the invention described in claim 2;

FIG. 8 is a sectional view taken along line DD of FIG. 7;

[Explanation of symbols]

 2 Open impeller or closed impeller (impeller) 3 Casing 4 Center part of casing 5 Water suction port (fluid suction port) 6 Swirling chamber or spiral winding chamber 7 Water discharge port (discharge port) 8D Drain pump drive Hydraulic motor O Winding start point of spiral chamber R Rotation direction of impeller

Claims (2)

[Claims] 1. An impeller is rotatably housed,
A fluid suction port that opens to face the center of the impeller, and is rotated from the fluid suction port into the center by the rotation of the impeller, then rotates with the impeller, and discharges from the entire circumference of the impeller by centrifugal force. Fluid chamber such as a centrifugal pump or a centrifugal blower, which is provided with a swirl chamber for receiving the fluid to be discharged and guiding the fluid to a fluid discharge port, and the swirl chamber is formed concentrically with the impeller and formed in a cylindrical shape having a uniform inner diameter. In the casing, the axial length of the swirl chamber is gradually increased from a position far from the fluid discharge port in the rotation direction of the impeller toward the fluid discharge port, so that a cross-sectional area of the swirl chamber is increased. A fluid machine, such as a centrifugal pump or a centrifugal blower, characterized in that the flow rate in the swirling chamber is made uniform in the circumferential direction by gradually increasing as the fluid outlet is approached from a position far from the outlet. Grayed. 2. An impeller is rotatably housed therein.
A fluid suction port that opens to face the center of the impeller, and is rotated from the fluid suction port into the center by the rotation of the impeller, then rotates with the impeller, and discharges from the entire circumference of the impeller by centrifugal force. A centrifugal pump, a centrifugal blower or the like for a casing of a fluid machine having a volute that receives the fluid to be discharged and guides the fluid to a fluid discharge port, and the volute is formed in a volute shape eccentric to the impeller. The axial length of the winding chamber is gradually increased from the winding start point of the spiral chamber toward the fluid discharge port, and the sectional area of the spiral chamber is gradually increased from the winding start point toward the fluid discharge port. A casing for a fluid machine such as a centrifugal pump or a centrifugal blower, wherein the casing is configured so that the flow rate in the spiral chamber becomes uniform in the circumferential direction by increasing the volume.