JP6873031B2 - Centrifugal casing and centrifugal pump - Google Patents

Description

The present invention relates to a casing for a centrifugal pump and a centrifugal pump including the casing.

Generally, in a sewage pump, clogging of the pump by foreign matter contained in sewage, which is a handling liquid, becomes a problem.

An example of the structure of a conventional sewage pump is shown in FIG. As an example, FIG. 8 shows a sewage submersible pump provided with a so-called open impeller, which does not have a side plate on the front surface of the impeller. The submersible pump of FIG. 8 includes a motor unit 2 that drives the spindle 1 and a pump unit 3 that pumps water by rotating the spindle 1. Then, the main shaft 1 is sealed between the pump unit 3 and the motor unit 2 with mechanical seals 4-1 and 4-2 so that the pressure water of the pump unit 3 does not leak to the motor unit 2 side.

In the motor unit 2, a rotor 5 that rotates integrally with the spindle 1 and a stator 7 having a stator winding are housed in the motor chamber 8. The motor chamber 8 is watertightly sealed by a substantially cylindrical motor frame 10 opened upward and a motor cover 11 connected to the upper end of the motor frame 10, and an underwater cable 12 is connected to the upper portion. ing.

The spindle 1 is rotatably supported via an upper bearing 13 attached to the motor cover 11 and a lower bearing 15 attached to the inner peripheral surface of the load-side bracket 14 connected to the lower end of the motor frame 10. Further, a handle 16 for suspending or moving the pump to a spring water site or the like is provided on the upper surface of the motor cover 11.

On the other hand, the pump unit 3 includes an open impeller 41 having a plurality of blades 40 and connected to the tip of the main shaft 1 so as to rotate integrally with the blades 40.

The pump unit 3 forms a pump chamber for accommodating the impeller 41, and includes a pump casing 30 having a discharge port 42a and a suction port 42b. The pump casing 30 includes a suction cover (in other words, a suction side casing) 31 and a discharge side casing 32. The suction cover 31 has an enlarged diameter upward, and the trailing edge portion (in other words, the radial tip portion or the tip portion) of each blade 40 is arranged close to the inner peripheral surface of the suction cover 31. .. The impeller 41 sucks in spring water, sewage, etc. from the suction port 42b of the suction cover 31 and discharges it from the discharge port 42a on the side surface of the discharge side casing 32. A discharge curved pipe 24 is connected to the discharge port 42a.

FIG. 9 is a plan view of the pump casing 30 (specifically, the discharge side casing 32) shown in FIG. The impeller 41 and the like housed in the pump casing 30 are not shown.

As an example, the sewage submersible pump of FIG. 8 has the form of a centrifugal pump. Therefore, as shown in FIG. 9, the pump casing 30 (in the illustrated example, the discharge side casing 32) has a volute portion 33 forming a volute chamber (in other words, a swirl chamber) 33A around the impeller. A discharge pipe 34 forming a discharge path 34A connecting the volute chamber 33A and the discharge port 42a can be provided. In such a pump casing 30 for a centrifugal pump, in order to separate the flow of the spiral sewage in the volute chamber 33A from the flow in the discharge path 34A, the tongue is placed at the start point (that is, the start of winding) of the volute portion 33. The portion 36 is formed. The tongue portion 36 extends so as to substantially project in the circumferential direction of the impeller. The sewage flowing in from the suction port 42b (see FIG. 8) flows into the volute portion 33 from the inner peripheral side of the volute chamber 33A through an impeller (not shown), flows through the discharge pipe 34, and then discharges from the discharge port 42a. Will be done. As shown in FIG. 8, the volute portion 33 has an outer periphery arranged between the upper surface portion 33a defining the upper surface of the volute chamber 33A, the bottom surface portion 33b defining the bottom surface, and the upper surface portion 33a and the bottom surface portion 33b. It has a face portion 33c and. The outer peripheral surface portion 33c projects laterally from the upper surface portion 33a and the bottom surface portion 33b so as to define the outer peripheral side of the volute chamber 33A.

10 to 11A are views showing a conventional configuration of a tongue portion 36 provided in a pump casing 30 for a centrifugal pump. 10A is a cross-sectional arrow view taken along the line A1-A1 of FIG. 9, and FIG. 10A is an upward perspective view of the pump casing 30 of FIG. 11 and 11A are views corresponding to FIGS. 10 and 10A showing another conventional example of the tongue portion 36. As shown in FIGS. 10 and 10A, the tongue portion 36 provided in the conventional centrifugal pump casing 30 has a front edge portion 37 with respect to the central axis C of the impeller (see FIGS. 8 and 9). It is formed so as to be parallel to each other, or as shown in FIGS. 11 and 11A, so that the front edge portion 37 thereof has an R shape along the inner peripheral surface of the discharge pipe 34.

However, the conventional tongue portion 36 as described above is likely to be covered with a thin film-like foreign substance such as a vinyl sheet contained in sewage, and is likely to stay on the tongue portion 36. The foreign matter accumulated in this way causes clogging of the pump.

Patent Document 1 describes a thread groove in a sewage pump in a direction of sending fibers, solids, etc. that have entered the gap into a portion facing the gap with the pump casing, such as the outer peripheral surface of the rear shroud of the impeller, to the outside of the gap. It is stated that As a result, foreign matter such as a piece of cloth is caught in the screw groove, receives thrust from the rotating screw groove, and is discharged along the screw groove to the outlet of the gap.

Japanese Patent Application Laid-Open No. 56-35000

According to one embodiment of the present invention, it is possible to provide a pump casing for a centrifugal pump that can prevent foreign matter from staying on the tongue. Further, according to one embodiment of the present invention, it is possible to provide a centrifugal pump provided with a pump casing for a centrifugal pump, which can prevent foreign matter from staying in the tongue portion.

According to one embodiment of the present invention, which is a pump casing for a centrifugal pump, a volute portion forming a volute chamber around an impeller housed in the pump casing, and a discharge connecting the volute chamber and a discharge port. It comprises a discharge pipe forming a path, and the inner surface of the volute portion has a spiral-shaped portion in the form of at least one discontinuous spirally extending groove or protrusion on the inner peripheral side of the volute chamber. A pump casing is provided.

It is a top view of the pump casing for a centrifugal pump according to 1st Embodiment of this invention. It is a partially enlarged view of FIG. It is sectional drawing along the line A2-A2 of FIG. It is an upper perspective view of the pump casing of FIG. It is a figure which shows the pump casing for the centrifugal pump by 2nd Embodiment of this invention, and is the figure corresponding to FIG. It is a figure which shows the pump casing for the centrifugal pump by the 3rd Embodiment of this invention, and is the figure corresponding to FIG. It is a figure which shows the pump casing for the centrifugal pump by 4th Embodiment of this invention, and is the figure corresponding to FIG. It is a figure which shows an example of the cross-sectional shape of the groove which constitutes a spiral shape part. It is a figure which shows an example of the cross-sectional shape of the groove which constitutes a spiral shape part. It is a figure which shows an example of the cross-sectional shape of the groove which constitutes a spiral shape part. It is a figure which shows an example of the cross-sectional shape of the groove which constitutes a spiral shape part. It is a figure which shows an example of the cross-sectional shape of the protrusion which constitutes a spiral shape part. It is a figure which shows an example of the cross-sectional shape of the protrusion which constitutes a spiral shape part. It is a figure which shows an example of the cross-sectional shape of the protrusion which constitutes a spiral shape part. It is a figure which shows an example of the cross-sectional shape of the protrusion which constitutes a spiral shape part. It is a side sectional view which shows an example of the conventional centrifugal pump. It is a top view of the pump casing for the centrifugal pump of FIG. It is a figure which shows the conventional example of the tongue part of a pump casing. It is a figure which shows the conventional example of the tongue part of a pump casing. It is a figure corresponding to FIG. 10 which shows another conventional example of the tongue part of a pump casing. It is a figure corresponding to FIG. 10A which shows the other conventional example of the tongue part of a pump casing.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings. The following description is merely an example, and does not mean that the technical scope of the present invention is limited to the following embodiments. Further, in the drawings, the same or corresponding components are designated by the same reference numerals, and duplicate description will be omitted. In the following description, the terms indicating the directions such as "up" and "down" mean the directions in the installed state of the centrifugal pump shown in FIG. Further, the embodiment of the present invention is characterized by the pump casing of the centrifugal pump. Therefore, in the following description, the components of the pump casing will be mainly described. The other components of the pump unit and the configuration of the motor unit may be any conventionally known configuration other than those described with reference to FIG.

[First Embodiment]
FIG. 1 is a plan view showing an example of a pump casing 130 for a centrifugal pump according to the first embodiment of the present invention. The pump casing 130 of FIG. 1 is applicable to, for example, the centrifugal pump shown in FIG. The pump casing 130 forms a volute portion 133 that forms a volute chamber (in other words, a spiral chamber) 133A around an impeller (not shown), and a discharge path 134A that connects the volute chamber 133A and the discharge port 142a. The discharge pipe 134 is provided. Further, in order to separate the spiral sewage flow in the volute chamber 133A from the flow in the discharge path 134A, a tongue portion 136 is formed at the start point (in other words, the start of winding) of the volute portion 133. For example, as shown in FIG. 1A, which is a partially enlarged view of FIG. 1, the tongue portion 136 extends so as to substantially project in the circumferential direction of the impeller. For ease of understanding, in FIG. 1A, the spiral shaped portions 200 and 300 shown in FIG. 1 and described later are not shown. The sewage flowing in from the suction port (for example, 42b shown in FIG. 8) flows into the volute portion 133 from the inner peripheral side of the volute chamber 133A through an impeller (not shown), flows through the discharge pipe 134, and then discharge port 142a. Is discharged from. The impeller housed in the pump casing 130 is usually arranged so as to rotate in the clockwise direction in FIG. In FIG. 1A, the direction of rotation of the impeller is indicated by an arrow R. Further, as shown in FIG. 2 described later, the volute portion 133 is located between the upper surface portion 133a that defines the upper surface of the volute chamber 133A, the bottom surface portion 133b that defines the bottom surface, and the upper surface portion 133a and the bottom surface portion 133b. It can have an outer peripheral surface portion 133c to be arranged. The outer peripheral surface portion 133c projects laterally from the upper surface portion 133a and the bottom surface portion 133b so as to define the outer peripheral side of the volute chamber 133A.

FIG. 2 is a cross-sectional view taken along the line A2-A2 of FIG. FIG. 2A is an upward perspective view of the pump casing 130 of FIG.

In the first embodiment, the inner surface (shown by a broken line in FIG. 1) of the volute portion 133 of the pump casing 130 has a spiral-shaped portion 200 extending in a spiral shape. In the illustrated example, the spiral shaped portion 200 has a groove shape. However, as will be described later, the spiral-shaped portion 200 may have the form of protrusions. For example, as shown in the example of FIG. 8, the inner peripheral side of the volute chamber (33A in FIG. 8) of the pump casing for centrifugal pump is open toward the outlet of the impeller (41 in FIG. 8). Therefore, in the first embodiment, the spiral-shaped portion 200 provided on the inner surface of the volute portion 133 is discontinuous on the inner peripheral side of the volute chamber 133A. In other words, the spiral portion 200 is composed of a plurality of curved portions 201 having the form of a plurality of grooves or protrusions that are divided on the inner peripheral side of the volute chamber 133A and separated from each other in the extending direction. Each of the plurality of curved portions 201 forms a part of a single spiral that is common to each other.

In the first embodiment, the entire shape including the plurality of curved portions 201 and the discontinuous portion of the curved portions 201 on the inner peripheral side of the volute chamber 133A is referred to as a spiral. In the illustrated example, the spiral shaped portion 200 is formed right-handed. In other words, each of the plurality of curved portions 201 constituting the spiral-shaped portion 200 is arranged so as to form an upward-sloping curve toward the discharge port 142a. However, as will be described later, the spiral-shaped portion 200 may be formed in a left-handed manner (in other words, each curved portion 201 is arranged so as to form a downward-sloping curve toward the discharge port 142a. May be good).

The spiral shaped portion 200, which has the form of a spiral groove or protrusion as a whole, can cause a twist in the water flow passing through the impeller, and the twisted water flow can be applied to the tongue portion 136. .. Therefore, even if the foreign matter is caught on the tongue portion 136, the foreign matter can be swept away by a strong flow, so that the foreign matter can be prevented from staying on the tongue portion 136. The range in which the spiral-shaped portion 200 is formed in the volute portion 133 is not particularly limited as long as the twisted water flow can be applied to the tongue portion 136 with sufficient strength to push out the foreign matter. The spiral-shaped portion 200 is provided within a predetermined angle range A (see FIG. 1A) around the central axis C of the impeller from the end (described later) of the front edge portion 137 of the tongue portion 136 toward the upstream side of the water flow. be able to.

In the first embodiment, the shape of the front edge portion 137 of the tongue portion 136 is different from the conventional example shown in FIGS. 9 to 11A. As shown in FIG. 2, the front edge portion 137 of the tongue portion 136 of the first embodiment is formed so as to be inclined with respect to the central axis C (see FIG. 1) of the impeller. Here, the "front edge portion 137 of the tongue portion 136" means the tip portion of the tongue portion 136 in the extension direction substantially along the outer circumference of the impeller. Further, "the front edge portion 137 of the tongue portion 136 is inclined" means that when the vertical end portions 137a and 137b of the front edge portion 137 are connected by a straight line, the straight line is with respect to the central axis C of the impeller. Means to incline.

On the other hand, in the tongue portion 36 of the conventional example shown in FIGS. 11 and 11A, for example, when the vertical end portions 37a and 37b of the front edge portion 37 are connected by a straight line, the straight line is the central axis C of the impeller. On the other hand, it is substantially parallel. At least in this respect, the tongue portion 136 of the first embodiment has a shape different from that of the tongue portion 36 of the conventional example.

The front edge portion 137 of the tongue portion 136 inclined in this way has an end portion (in other words, an end) 137b located closer to the discharge port 142a and an end portion (in other words, a terminal portion) located on the side farther from the discharge port 142a. For example, it will have a starting end) 137a. In the example of FIG. 2, the front edge portion 13 of the tongue portion 136
The start end 137a of 7 is arranged on the lower side of FIG. 2, and the end end 137b is inclined so as to be arranged on the upper side of FIG. In other words, the front edge portion 137 of the tongue portion 136 is inclined in the upward direction from the start end 137a to the end end 137b. With this configuration, the foreign matter caught on the tongue portion 136 can be smoothly moved toward the discharge port 142a along the inclination of the front edge portion 137 of the tongue portion 136. According to another embodiment, the front edge portion 137 of the tongue portion 136 may be inclined in the downward direction from the start end 137a to the end end 137b.

Further, the tongue portion 136 having the inclined front edge portion 137 can suppress a sudden pressure change (in other words, pulsation) when the tip of the blade of the impeller passes through the tongue portion 136. Therefore, the vibration of the pump can be suppressed.

As described above, the spiral-shaped portion 200 is composed of a plurality of curved portions 201 having the form of a plurality of grooves or protrusions that are divided on the inner peripheral side of the volute chamber 133A and separated from each other in the extending direction. Each curved portion 201 has an upstream end portion 201a located on the upstream side of the water flow F (see FIG. 2) and a downstream end portion 201b located on the downstream side of the water flow F. In the first embodiment, in particular, among the plurality of curved portions 201, the downstream end portion 201b of the curved portion 201 arranged on the most downstream side of the water flow F is referred to as "the end 201b'of the spiral-shaped portion 200". .. In the first embodiment, the end 201b'of the spiral-shaped portion 200 is arranged so as to reach the end 137b of the front edge portion 137 of the inclined tongue portion 136. By arranging the end 201b'of the spiral shape portion 200 so as to reach the end 137b of the front edge portion 137 of the tongue portion 136, a strong flow is applied to the foreign matter that has moved to the end 137b of the front edge portion 137 of the tongue portion 136. Since it can be directly applied, foreign matter can be easily discharged. However, the end 201b'of the spiral-shaped portion 200 does not necessarily have to reach the end 137b of the front edge portion 137 of the tongue portion 136. It should be noted that "the end 201b'of the spiral-shaped portion 200 reaches the end 137b of the front edge portion 137 of the tongue portion 136" means that the edge portion defining the groove or protrusion of the terminal 201b'of the spiral-shaped portion 200 is the tongue. It means a state of being connected to the end 137b of the front edge portion 137 of the portion 136.

Further, according to another embodiment, the front edge portion 137 of the tongue portion 136 does not have to be inclined with respect to the central axis C of the impeller. The spiral shaped portion 200, which forms a spiral groove or protrusion as a whole as described above, can cause a twist in the water flow passing through the impeller, and the twisted water flow can be applied to the tongue portion 136. Therefore, the foreign matter caught on the tongue 136 can be swept away with a strong flow. Therefore, even when the front edge portion 37 of the tongue portion 36 is not inclined with respect to the central axis C of the impeller as in the conventional example, foreign matter stays in the tongue portion 36 and the pump is blocked. Can be prevented. However, when the front edge portion 137 of the tongue portion 136 is inclined with respect to the central axis C of the impeller as in the first embodiment, the foreign matter caught on the tongue portion 136 is discharged along the inclination. Since it can be smoothly moved to the side, it is possible to make it easier to discharge the foreign matter to the discharge port 142a side.

In the first embodiment, one spiral-shaped portion 200 is provided, but according to another embodiment, a plurality of spiral-shaped portions 200 may be provided. In this case, both a spiral groove and a spiral protrusion may be provided. Further, at least one end 201b'of the spiral-shaped portion 200 can be arranged so as to reach the end 137b of the front edge portion 137 of the inclined tongue portion 136.

Further, in the first embodiment, in addition to the spiral-shaped portion (hereinafter, also referred to as the first spiral-shaped portion) 200 of the volute portion 133, a single spiral extending continuously on the cylindrical inner surface of the discharge pipe 134. A shape portion (hereinafter, also referred to as a second spiral shape portion) 300 is provided. In the illustrated example, the second spiral shaped portion 300 has a groove shape. However, the second spiral-shaped portion 300 may have the form of a protrusion. Further, as the second spiral-shaped portion 300, it is also possible to provide a plurality of spiral-shaped portions 300. In this case, both a spiral groove and a spiral protrusion can be provided.

In the first embodiment, as shown in FIG. 2, the starting end (in other words, the end located on the side far from the discharge port 142a) 300a of the second spiral-shaped portion 300 is set on the first spiral-shaped portion 200. It can be arranged so as to connect to the end 201b'(in the illustrated example, it is also the end 137b of the front edge 137 of the tongue 136). As a result, the twisted water flow generated by the first spiral-shaped portion 200 can be guided to the discharge port 142a without impairing the strength of the flow. Therefore, the foreign matter can be more easily discharged from the tongue portion 136 to the discharge port 142a. However, the start end 300a of the second spiral shape portion 300 and the end end 201b'of the first spiral shape portion 200 do not necessarily have to be connected. In addition, "the start end 300a of the second spiral shape portion 300 is connected to the end 201b'of the first spiral shape portion 200" means an edge portion that defines a groove or a protrusion of the start end 300a of the second spiral shape portion 300. Means connected to the edge defining the groove or protrusion at the end 201b'of the first spiral portion 200.

In the illustrated example, the second spiral shaped portion 300 is right-handed toward the discharge port 142a. That is, a right-handed second spiral-shaped portion 300 is formed with respect to the right-handed first spiral-shaped portion 200. By winding the second spiral shape portion 300 in the same winding manner as the first spiral shape portion 200, the start end 300a of the second spiral shape portion 300 is connected to the end 201b'of the first spiral shape portion 200. Since it can be arranged, it is easy to maintain the strength of the twisted water flow. However, the second spiral-shaped portion 300 may be left-handed with respect to the right-handed first spiral-shaped portion 200. Further, when a plurality of second spiral-shaped portions 300 are provided, at least the starting end 300a of the first second spiral-shaped portion 300 is set to the first spiral-shaped portion 200 (the first spiral-shaped portion 200 is provided. When a plurality of rows are provided, they can be arranged so as to be connected to the end 201b'of at least one spiral shape portion 200).

However, according to other embodiments, the second spiral shaped portion 300 may not be provided.

[Second Embodiment]
FIG. 3 is a diagram corresponding to FIG. 2 showing a second embodiment. Unlike the first embodiment, in the second embodiment, the groove (specifically, the groove formed by the plurality of curved portions 401) forming the first spiral shape portion 400 is formed in a left-handed manner. In other words, each curved portion 401 is arranged so as to form a downward-sloping curve toward the discharge port 142a. Therefore, the end 401b'of the first spiral shaped portion 400 is located on the lower side of FIG. Further, in the second embodiment, the direction of inclination of the front edge portion 237 of the tongue portion 236 is different from that of the first embodiment, the start end 237a is arranged on the upper side of FIG. 3, and the end end 237b is on the lower side of FIG. Inclined to be placed in. In other words, the front edge portion 237 of the tongue portion 236 is inclined downward from the start end 237a to the end end 237b. In such a downwardly inclined front edge portion 237, the foreign matter moves along the inclination of the front edge portion 237 to the end 237b of the front edge portion 237. In the illustrated example, the end 401b'of the first spiral-shaped portion 400 (in other words, the downstream end 401b of the curved portion 401 arranged on the most downstream side of the water flow F among the plurality of curved portions 401) is It is arranged so as to reach the end 237b of the front edge portion 237. As a result, a strong flow through the end 401b'of the first spiral-shaped portion 400 can be directly applied to the foreign matter. However, the end 401b'of the first spiral shaped portion 400 does not necessarily have to reach the end 237b of the front edge portion 237. Further, the front edge portion 237 may have an ascending inclination as in the first embodiment with respect to the left-handed first spiral-shaped portion 400. Further, as in the first embodiment, the front edge portion 237 does not have to be inclined.

Further, in the second embodiment, the second spiral-shaped portion 500 is formed left-handed like the first spiral-shaped portion 400. Further, in the example of FIG. 3, the start end 50 of the second spiral shape portion 500
0a is arranged so as to be connected to the end 401b'of the first spiral-shaped portion 400 (also the end 237b of the front edge portion 237 in the illustrated example).

As a result, the twisted water flow guided by the left-handed first spiral-shaped portion 400 is also guided by the left-handed second spiral-shaped portion 500 toward the discharge port 142a without impairing the strength of the flow. .. However, the start end 500a of the second spiral shape portion 500 and the end end 401b'of the first spiral shape portion 400 do not necessarily have to be connected. Further, the right-handed second spiral-shaped portion 500 may be arranged with respect to the left-handed first spiral-shaped portion 400.

[Third Embodiment]
FIG. 4 is a diagram corresponding to FIG. 2 showing a third embodiment. Unlike the configuration of FIG. 2, in the third embodiment, the width of the curved portion 201 located at least on the most downstream side of the water flow F among the plurality of curved portions 201 constituting the first spiral-shaped portion 200 is the curve. It is configured to become smaller from the upstream side end portion 201a of the portion 201 toward the downstream side end portion 201b. As a result, the strength of the water flow applied to the tongue portion 136 can be increased. However, according to another embodiment, the width of the first spiral shape portion 200 is from the start end 201a to the end end 201b'of the first spiral shape portion 200 (that is, the most of the water flow among the plurality of curved portions 201). (From the upstream end 201a of the curved portion 201 located on the upstream side to the downstream end 201b of the curved portion 201 located on the most downstream side of the water flow), the size may be gradually reduced. Note that FIG. 4 shows, as an example, a tongue portion 136 having right-handed first and second spiral shaped portions 200 and 300 and an ascending leading edge portion 137, which is the third embodiment. Does not limit.

[Fourth Embodiment]
As described above, the first spiral-shaped portions 200 and 400 and the second spiral-shaped portions 300 and 500 may have the form of protrusions. FIG. 5 shows a fourth embodiment, in which, as an example, both the first spiral-shaped portion 600 and the second spiral-shaped portion 700 have the form of protrusions. However, according to other embodiments, one of the first and second spiral shaped portions may have the form of a groove and the other may have the form of a protrusion. Further, when a plurality of first spiral-shaped portions are provided, both the spiral groove and the spiral protrusion may be formed as the first spiral-shaped portion. Similarly, when a plurality of second spiral-shaped portions are provided, both the spiral groove and the spiral protrusion may be formed as the second spiral-shaped portion. 6A to 6D show examples of cross-sectional shapes of the grooves forming the first and / or second spiral shape portions. 7A-7D show examples of cross-sectional shapes of the protrusions that make up the first and / or second spiral shape. However, as long as the water flow can be twisted, the cross-sectional shapes of the grooves and protrusions forming the first and / or second spiral shape portions are not limited to those shown in the drawings. Note that FIG. 5 shows, as an example, a tongue portion 136 having right-handed first and second spiral shaped portions 600, 700 and an ascending leading edge portion 137, which is the fourth embodiment. Does not limit.

The pump casing of each embodiment can be manufactured using a conventional casting method. The first and / or the second spiral-shaped portion can be formed by forming the corresponding spiral-shaped portion in the mold in advance. Alternatively, the first and / or second spiral shaped portion may be rolled into the pump casing after casting.

Although the embodiments of the present invention have been described above, the above-described embodiments of the invention are for facilitating the understanding of the present invention and do not limit the present invention. The present invention can be modified and improved without departing from the spirit thereof, and it goes without saying that the present invention includes an equivalent thereof. In addition, any combination or omission of the claims and the components described in the specification is possible within the range in which at least a part of the above-mentioned problems can be solved, or in the range in which at least a part of the effect is exhibited. Is.

The present invention includes the following aspects.
1. 1. A pump casing for a centrifugal pump, provided with a volute portion that forms a volute chamber around an impeller housed in the pump casing, and a discharge pipe that forms a discharge path connecting the volute chamber and a discharge port. , The inner surface of the volute portion is a pump casing having a spiral-shaped portion having the form of a groove or a protrusion extending in a discontinuous spiral shape on the inner peripheral side of the volute chamber.
2. Above 1. In the pump casing according to the above, the pump casing is provided with a tongue portion protruding in the circumferential direction of the impeller at the starting point of the volute portion, and the spiral-shaped portion causes a twist in the water flow toward the discharge port and is twisted. A pump casing in which the water stream is placed so that it hits the tongue.
3. 3. Above 2. In the pump casing according to the above, with respect to the central axis of the impeller so that the front edge portion of the tongue portion has an end located closer to the discharge port and a start end located on the side farther from the discharge port. Inclined, pump casing.
4. Above 3. In the pump casing according to the above, at least one spiral-shaped portion is provided within a predetermined angle range around the central axis of the impeller from the end of the front edge portion of the tongue portion toward the upstream side of the water flow. The pump casing.
5. Above 2. ~ 4. The pump casing according to any one of the above, wherein at least one spiral-shaped portion has a start end located on the most upstream side with respect to the water flow and an end position located on the most downstream side with respect to the water flow. A pump casing in which the end of at least one spiral shape is located at the end of the front edge of the tongue.
6. 5. Above. The pump casing according to the above, wherein at least one spiral-shaped portion is arranged right-handed, and the front edge portion of the tongue portion is inclined upward from the start end to the end end.
7. 5. Above. The pump casing according to the above, wherein at least one spiral-shaped portion is arranged left-handed, and the front edge portion of the tongue portion is inclined downward from the start end to the end end.
8. Above 2. ~ 4. In the pump casing according to any one of the above, at least one spiral-shaped portion of the volute portion is the first spiral-shaped portion, and the first spiral-shaped portion is located on the most upstream side with respect to the water flow. The pump casing has at least one groove or protrusion that is provided on the inner surface of the discharge pipe and has a starting end and a terminal located most downstream with respect to the water flow. It has two spiral-shaped portions, and the second spiral-shaped portion has a start end located on the upstream side with respect to the water flow and an end located on the downstream side with respect to the water flow, and has a second spiral shape portion. The starting end of the spiral-shaped portion is a pump casing arranged at the end of the first spiral-shaped portion.
9. 5. Above. ~ 7. In the pump casing according to any one of the above, at least one spiral-shaped portion of the volute portion is a first spiral-shaped portion, and the pump casing is further provided on the inner surface of the discharge pipe and extends continuously. It has at least one second spiral shaped portion in the form of a groove or protrusion, the second spiral shaped portion located upstream of the water flow and downstream of the water flow. A pump casing that has an end to the end and the start of the second spiral is located at the end of the first spiral.
10. Above 2. ~ 4. In the pump casing according to any one of the above, at least one spiral-shaped portion has a start end located on the most upstream side with respect to the water flow and an end position located on the most downstream side with respect to the water flow. A pump casing in which the width of at least one spiral-shaped portion decreases from the beginning to the end.
11. 5. Above. ~ 9. The pump casing according to any one of the above, wherein the width of at least one spiral-shaped portion decreases from the start end to the end of at least one spiral-shaped portion.
12. Above 2. ~ 9. The pump casing according to any one of the above, wherein at least one spiral-shaped portion has a plurality of grooves or protrusions which are divided on the inner peripheral side of the volute chamber and are separated from each other in the extending direction. It is composed of curved portions, and each of the plurality of curved portions has an upstream end portion located on the upstream side with respect to the water flow and a downstream end portion located on the downstream side with respect to the water flow. A pump casing in which the width of the curved portion located closest to the tongue decreases from the upstream end to the downstream end.
13. Above 1. ~ 12. Centrifugal pump with the pump casing according to any one of.

The present invention is widely applicable to centrifugal pumps.

A Angle range C Central axis of impeller R Direction of rotation of impeller F Direction of water flow W1, W2 Width 1 Main shaft 2 Motor unit 3 Pump unit 4-1 and 4-2 Mechanical seal 5 Rotor 7 Stator 8 Motor chamber 10 Motor frame 11 Motor cover 12 Submersible cable 13 Upper bearing 14 Load side bracket 15 Lower bearing 16 Handle 24 Discharge curved pipe 30 Pump casing 31 Suction cover (suction side casing)
32 Discharge side casing 33 Volute 33a Top surface 33b Bottom 33c Outer surface 33A Volute chamber 42a Discharge port 42b Suction port 34 Discharge pipe 34a Discharge path 36 Tongue 37 Tongue front edge 37a Upper end 37b Lower end 130 of the front edge of the tongue Pump casing (discharge side casing)
133 Volite part 133a Top part 133b Bottom part 133c Outer surface part 133A Outer surface part 133A Volute chamber 142a Discharge port 134 Discharge pipe 134a Discharge path 136 Tongue part 137 Front edge part of tongue part 137a Start end of front edge part of tongue part 137b Front edge part of tongue part Ends 200, 400, 600 First spiral shaped portions 201, 401, 601 Curved portions 201a, 401a, 601a Upstream end portions 201b, 401b, 601b of curved portions Downstream end portions 201b', 401b', of curved portions 601b'Termination of the first spiral shape portion 300, 500, 700 Second spiral shape portion 300a, 500a, 700a Start end of the second spiral shape portion 300b, 500b, 700b Termination of the second spiral shape portion

Claims (12)

A pump casing for centrifugal pumps
It is provided with a volute portion that forms a volute chamber around an impeller housed in the pump casing, and a discharge pipe that forms a discharge path that connects the volute chamber and a discharge port.
It said inner surface of the volute portion, have a spiral-shaped part in the form of a discontinuous least 1 Article grooves or projections extending spiral in the inner of the volute chamber,
The pump casing includes a tongue portion that projects in the circumferential direction of the impeller at the start point of the volute portion.
The spiral-shaped portion is a pump casing in which the water flow toward the discharge port is twisted and the twisted water flow is arranged so as to hit the tongue portion. The pump casing according to claim 1.
The front edge of the tongue is inclined with respect to the central axis of the impeller so that it has an end located closer to the discharge port and a start end located farther from the discharge port. Pump casing. The pump casing according to claim 2.
At least one spiral-shaped portion is provided within a predetermined angular range around the central axis of the impeller from the end of the front edge portion of the tongue portion toward the upstream side of the water flow. casing. The pump casing according to any one of claims 1 to 3.
At least one of the spiral-shaped portions has a start end located on the most upstream side with respect to the water flow and an end position located on the most downstream side with respect to the water flow.
A pump casing in which the end of the at least one spiral shape portion is arranged at the end of the front edge portion of the tongue portion. The pump casing according to claim 4.
The at least one spiral-shaped portion is arranged right-handed.
A pump casing in which the front edge portion of the tongue portion is inclined upward from the start end toward the end. The pump casing according to claim 4.
The at least one spiral-shaped portion is arranged left-handed.
A pump casing in which the front edge portion of the tongue portion is inclined downward from the start end toward the end. The pump casing according to any one of claims 1 to 3.
At least one spiral-shaped portion of the volute portion is a first spiral-shaped portion, and the first spiral-shaped portion has a starting end located most upstream with respect to the water flow and the water flow. It has an end located on the most downstream side and has an end.
The pump casing further has at least one second spiral shaped portion provided on the inner surface of the discharge pipe and having the form of a continuously extending groove or protrusion.
The second spiral-shaped portion has a start end located on the upstream side with respect to the water flow and an end located on the downstream side with respect to the water flow.
A pump casing in which the starting end of the second spiral-shaped portion is arranged at the end of the first spiral-shaped portion. The pump casing according to any one of claims 4 to 6.
At least one spiral-shaped portion of the volute portion is a first spiral-shaped portion.
The pump casing further has at least one second spiral shaped portion provided on the inner surface of the discharge pipe and having the form of a continuously extending groove or protrusion.
The second spiral-shaped portion has a start end located on the upstream side with respect to the water flow and an end located on the downstream side with respect to the water flow.
A pump casing in which the starting end of the second spiral-shaped portion is arranged at the end of the first spiral-shaped portion. The pump casing according to any one of claims 1 to 3.
At least one of the spiral-shaped portions has a start end located on the most upstream side with respect to the water flow and an end position located on the most downstream side with respect to the water flow.
A pump casing in which the width of at least one spiral-shaped portion decreases from the start end to the end end. The pump casing according to any one of claims 4 to 8.
A pump casing in which the width of at least one spiral-shaped portion decreases from the start end to the end of the at least one spiral-shaped portion. The pump casing according to any one of claims 1 to 8.
The at least one spiral-shaped portion is composed of a plurality of curved portions having the form of a plurality of grooves or protrusions which are divided on the inner peripheral side of the volute chamber and are separated from each other in the extending direction.
Each of the plurality of curved portions has an upstream end portion located on the upstream side with respect to the water flow and a downstream end portion located on the downstream side with respect to the water flow.
A pump casing in which the width of the curved portion arranged at a position closest to the tongue portion decreases from the upstream end portion toward the downstream end portion. A centrifugal pump comprising the pump casing according to any one of claims 1 to 11.

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