JP2005240763A - Fluid pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the passing performance in a pump casing without worsening the pump efficiency extremely in a liquid pump for carrying liquid. <P>SOLUTION: This liquid pump includes: an impeller 11 for discharging liquid to the outer peripheral side; and a pump casing 12 provided with a volute-like discharge passage 50 formed surrounding the outer periphery of the impeller 11 to feed out a discharged liquid in the circumferential direction. The pump casing 12 is formed so that the sectional area of the passage 50 is decreased from the upstream side to the downstream side in a predetermined range from the end part 52 of the volute. Preferably the point of starting to decrease in the sectional area of the passage 50 is set within range of 30° to 120° in the circumferential direction from the end part 52 of the volute toward the cut water part 51 side. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid pump, and particularly belongs to the technical field of a high-passage pump that improves the passage of foreign matter and the like.

  Conventionally, various pumps for discharging liquid are known. For example, as shown in Patent Document 1, there are those provided with an impeller in which a spiral flow path is formed, and those provided with a screw type impeller. In the case of such a pump, generally, a volute-shaped pump casing is provided so as to surround the impeller, and the liquid discharged from the impeller is discharged by a discharge passage formed in the pump casing. Efficiently discharges outside the pump.

  More specifically, the pump casing is formed in a spiral shape in which the discharge flow path in the casing gradually increases in cross-sectional area toward the outlet side, and protrudes into the casing near the end of the volute. A protruding portion is provided, and the protruding end portion and the starting portion of the volute are partitioned by the protruding portion so that the liquid discharged from the impeller does not recirculate in the casing.

  However, in a pump having such a pump casing, when discharging sewage mixed with foreign matters such as foreign matters, the foreign matters are clogged in the impeller and the pump casing, particularly in a low flow rate range, and the flow path is blocked. There was a problem. In the pump casing in particular, when a liquid pressure difference occurs between the protruding end side of the volute and the starting start side of the volute in the projecting portion, foreign matter tends to move to the starting start side of the volute due to this pressure difference. Foreign matters are likely to be clogged in the protruding portion in the middle.

In order to eliminate such clogging of foreign matter in the pump casing, it is effective to reduce the liquid recirculation flow rate to the starting side by suppressing the increase in the pressure of the liquid on the end side of the volute. For this reason, it is conceivable to make the cross-sectional area of the discharge flow path substantially constant from the beginning of the volute (see, for example, Patent Documents 2 and 3).
Japanese Patent Publication No. 28-5840 Japanese Patent Publication No.31-1292 Japanese Patent Publication No. 7-26634

  However, as described above, if the cross-sectional area of the discharge flow path in the pump casing is made constant from the beginning, the passage of foreign matter is improved, but the energy given to the liquid by the impeller is effectively used by the pump casing. There is a problem in that the pump pressure cannot be converted to the discharge pressure and the pump efficiency is extremely deteriorated.

  The present invention has been made in view of the above points, and the object of the present invention is to devise the structure of the discharge flow path formed in the pump casing of the liquid pump to extremely deteriorate the pump efficiency. It is intended to make it difficult for a foreign object to be blocked.

  In order to achieve the above object, according to the first solution of the present invention, the cross-sectional area of the discharge flow path formed between the pump casing and the outer periphery of the impeller is limited to a predetermined range from the end of the volute. In order to decrease from upstream to downstream.

  Specifically, in the invention of claim 1, an impeller that discharges the liquid to the outer peripheral side, and a volute-shaped discharge passage that surrounds the outer periphery of the impeller and sends the discharged fluid in the circumferential direction are formed. And a liquid pump provided with a pump casing. And the said discharge flow path shall be formed so that it may have a site | part from which the cross-sectional area of a flow path becomes small toward a downstream from the upstream end part of a volute.

  With this configuration, since the cross-sectional area of the discharge flow path formed between the impeller and the pump casing is smaller than the upstream side in a predetermined range from the end of the volute, the liquid at the end of the volute This speed is higher than in the case of a conventional general pump casing, and the pressure rise of the liquid is suppressed. As a result, the pressure difference between the liquid at the side of the whispering end and the side of the whirling start partitioned by the projecting portion of the pump casing can be reduced, and the clogging of foreign matter at the projecting portion can be reduced.

  In addition, since only the cross-sectional area of the discharge channel within a predetermined range from the end of the volute is smaller than the upstream side, the discharge cross-section is constant compared to the case where the cross-sectional area of the discharge channel is constant from the start of the volute. The pressure can be increased and the pump efficiency is not significantly reduced.

  That is, according to the liquid pump of the present invention, it is possible to improve the passage of foreign matter in the pump casing without extremely deteriorating the pump efficiency.

  In the above-described configuration, the point where the cross-sectional area of the discharge flow path starts to decrease is preferably set within a range of 30 to 120 degrees in the circumferential direction from the end of the volute to the start of the start ( Invention of Claim 2).

  Here, since the clogging in the pump may occur not only in the pump casing but also in the impeller, in the pump casing structure as described above, the impeller has a suction port formed at one end side in the rotation axis direction. In addition, a discharge port is formed on the side of the other end side, and the inside is a substantially cylindrical one in which a spiral flow path communicating the suction port and the discharge port is formed, On the outer peripheral surface of the impeller, there is provided a flange portion that protrudes outward over the entire circumference between the suction port and the discharge port, and one of the outer peripheral surfaces closer to the discharge port than the flange portion. It is more preferable that a radial flow type blade portion is formed so as to be recessed and communicate with the discharge port and extend in the circumferential direction (invention of claim 3).

  In this way, the impeller is a so-called closed impeller in which the suction port side and the discharge port side are partitioned by the flange portion, and the suction port and the discharge port are communicated with each other through a spiral channel. Foreign substances and the like can flow smoothly along the spiral flow path, and can be made difficult to block in the impeller. Moreover, since the sewage sucked from the suction port is transported by the spiral flow path and the radial flow blades formed on the outer peripheral surface of the impeller, the discharge pressure is increased and the pump efficiency is improved. can do.

  That is, a pump casing in which the cross-sectional area of the discharge flow path is reduced within a predetermined range from the end of the volute firing and an impeller as described above that can improve pump efficiency and hardly cause clogging inside. Therefore, it is possible to realize a liquid pump that has better passability and high pump efficiency.

  In the second solution of the present invention, the cross-sectional area of the discharge flow path formed between the pump casing and the outer periphery of the impeller is substantially constant only within a predetermined angle range from the end of the volute. .

  Specifically, in the invention of claim 4, in the liquid pump having the same premise configuration as that of the invention of claim 1, the discharge flow path extends from the end of the volute to the start side of the volute up to a predetermined angle in the circumferential direction. The cross-sectional area is substantially constant, and the predetermined angle is set within a range of 30 degrees to 210 degrees. Thereby, the same effect as that of claim 1 can be obtained.

  Here, that the cross-sectional area of the discharge channel is substantially constant means that the change in the channel cross-sectional area every 30 degrees is within 0.5%. That is, when the flow path cross-sectional area at a certain position is compared with the flow path cross-sectional area at a position advanced by 30 degrees toward the end of the winding within the predetermined angle range, the change in cross-sectional area Is within 0.5%, the channel cross-sectional area becomes substantially constant.

  According to the liquid pump according to the first and second aspects of the present invention, the portion where the cross-sectional area of the discharge channel decreases from the upstream side toward the downstream side is provided within a predetermined range from the volute end portion of the pump casing. In addition, foreign matter is less likely to be clogged in the pump casing, and the pump efficiency is not extremely deteriorated compared to the case where the cross-sectional area of the discharge flow path is constant from the beginning of the volute firing.

  According to the invention of claim 3, since the impeller is also difficult to close inside and has a structure with good pump efficiency, a liquid pump that is more efficient and difficult to close can be realized.

  Further, according to the liquid pump of the fourth aspect, since the cross-sectional area of the discharge flow path is substantially constant in the range of a predetermined angle from the volute end portion of the pump casing, the same effect as in the first aspect is obtained. be able to.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

(Overall configuration of sewage treatment pump)
As shown in FIG. 1, the sewage treatment pump 10 (liquid pump) according to the embodiment is a turbo-type submersible pump. The pump 10 includes an impeller 11 and a pump casing 12 that covers the impeller 11. And a hermetically sealed submersible motor 13 for rotating the impeller 11.

  The underwater motor 13 includes a motor 16 including a stator 14 and a rotor 15, and a motor casing 17 that covers the motor 16. A drive shaft 18 extending in the vertical direction is disposed at the approximate center of the rotor 15, and the drive shaft 18 is rotatably supported by bearings 19 and 20. The lower end of the drive shaft 18 is connected to the impeller 11, whereby the rotation of the submersible motor 13 is transmitted to the impeller 11.

  As will be described in detail later, the pump casing 12 covers the impeller 11 and forms a flow path 50 (discharge flow path) for discharging sewage (liquid) discharged from the impeller 11 to the outside of the pump. In the interior of the pump chamber 26 is formed a pump chamber 26 surrounded on the outer peripheral side by a side wall 12a curved in a semicircular shape in cross-sectional view, and a discharge portion 28 of the impeller 11 to be described later is formed in the pump chamber 26. (See FIG. 2) is housed. As shown in FIGS. 1, 12, and 13, a part of the pump chamber 26 constitutes the flow path 50 in a state where the impeller 11 is disposed in the pump casing 12.

  Further, as shown in FIG. 1, a suction part 21 protruding downward is formed in the lower part of the pump casing 12, and a suction port 22 opening downward is formed in the suction part 21. ing. The suction port 22 communicates with a suction port 29 of the impeller 11 described later. On the other hand, the side of the pump casing 12 is formed with a discharge portion 23 projecting sideways, and the discharge portion 23 is formed with a discharge port 24 that opens to the side. The discharge port 24 is an outlet of the flow path 50, and the sewage discharged from the impeller 11 is discharged from the discharge port 24 to the outside of the pump.

(Impeller)
As shown in FIG. 2, the impeller 11 is provided with a suction portion 27 and a discharge portion 28 in order from the lower side to the upper side in the axial direction. The suction part 27 and the discharge part 28 are both formed in a substantially cylindrical shape, and the discharge part 28 is configured to have a larger diameter than the suction part 27. A flange portion 40 is formed over the entire circumference between the discharge portion 28 and the suction portion 27, and as shown in FIG. 1, the discharge portion 28 and the suction portion 27 of the impeller 11 Is designed to be divided up and down. That is, the impeller 11 is a closed type impeller in which the suction portion 27 and the discharge portion 28 are partitioned by the flange portion 40.

  As shown in FIGS. 2 and 3, a suction port 29 that opens downward is provided at the lower end of the suction portion 27, while an upper end wall 30 is formed above the discharge portion 28. ing. An insertion hole 32 for inserting the tip of the drive shaft 18 is formed at the center of the upper end wall 30, and an attachment portion for attaching the drive shaft 18 around the insertion hole 32. 31 is formed.

  A part of the upper surface of the upper end wall 30 (here, the half of the upper end wall 30 and the side on which the weight of the impeller 11 is heavy) is formed with a recess 33 that is recessed downward as shown in FIG. Thereby, the weight balance of the whole impeller 11 is made uniform, and the stability of rotation is improved. However, the size and shape of the recess 33 of the upper end wall 30 are not limited at all. Further, the recess 33 is not necessarily required, and the shape of the upper end wall 30 is not particularly limited. For example, the upper surface of the upper end wall 30 may be flush.

  On the other hand, as shown in FIGS. 6, 9, and 11, the discharge portion 28 of the impeller 11 is formed with a discharge port 34 that opens toward the side, and inside the impeller 11, As shown in FIGS. 8 to 11, a spiral primary flow path 35 (spiral flow path) extending from the suction port 29 of the suction portion 27 to the discharge port 34 is defined. That is, as shown in FIG. 11, the discharge port 34 is formed so as to open toward the extending direction of the spiral primary flow path 35. In the present specification, a partition wall that partitions the primary flow path 35 is referred to as a primary blade 36.

  Further, as shown in FIGS. 3 and 5 to 11, a secondary flow path 37 that is recessed inward so as to extend along the outer peripheral surface is formed on a part of the outer peripheral surface of the discharge portion 28. The secondary flow path 37 is continuous with the downstream side of the primary flow path 35 formed in the impeller 11 at the discharge port 34. The secondary flow path 37 circulates around the discharge section 28 over a length of at least half the circumference of the impeller 11, and the downstream end of the secondary flow path 37 reaches the vicinity of the discharge port 34 as shown in FIG. 11. It is formed to extend. The length of the secondary flow path 37 is preferably not less than one half and less than one turn, but is not particularly limited.

  That is, the secondary flow path 37 is a non-spiral flow path, and the flow path center is located on an orthogonal plane orthogonal to the axis of the impeller. When the partition wall that partitions the secondary flow path 37 is referred to as a secondary blade 38 (blade portion), the secondary blade 38 is a so-called radial flow blade. It will be discharged to the side (radially outer side).

  Further, as shown in FIG. 11, the blade outlet angle θ <b> 2 of the secondary blade 38 is set smaller than the blade outlet angle θ <b> 1 of the primary blade 36. Here, the blade outlet angle is defined as the angle formed by the tip on the outlet side of the blade and the circumferential tangent. In the impeller 11, the outlet end (downstream end) 36A of the primary blade 36 is continuous with the upstream end of the secondary blade 38, and the outlet end of the primary blade and the inlet end of the secondary blade 38 The boundary portion is continuously formed with a curve, that is, the primary blade and the secondary blade are smoothly connected.

  Usually, when designing a blade, a predetermined function that represents the curve of the blade is often used. In the present embodiment, the primary blade 36 and the secondary blade 38 are designed with different functions.

  With the configuration of the pump 10 as described above, sewage is sucked from the suction port 29 of the impeller 11 and discharged outside the pump as follows. First, the impeller 11 is rotated by the submersible pump 13, and the primary blade 36 of the impeller 11 sucks sewage upward from the lower suction port 29 by this rotation. The sucked sewage passes through the spiral primary flow path 35 in the impeller 11 and is discharged to the outer peripheral side by the discharge port 34 and the secondary blade 38. At that time, since the impeller 11 rotates at a predetermined rotation speed, sewage is discharged from the entire circumference of the impeller 11. The discharged sewage is received by the pump casing 12 disposed so as to cover the impeller 11, flows to the discharge port 24 through the flow path 50 in the pump casing 12, and is discharged from the discharge port 24. It is discharged out of the pump.

  Thus, by conveying the sewage sucked from the suction port 29 of the impeller 11 by both the primary blade 36 and the secondary blade 38, the discharge pressure can be increased and the pump efficiency can be improved. Further, since the primary flow path 35 extending from the suction port 29 to the discharge port 34 is formed in a smooth spiral shape, there is little stagnation area in the flow path, and sewage flows smoothly in the primary flow path 35. Therefore, foreign matters such as foreign matters contained in the sewage are not easily clogged inside the impeller 11. Therefore, it is possible to maintain good passability of foreign matter, and to achieve both improved passability and improved efficiency.

(Pump casing)
Next, the structure of the pump casing 12, which is a characteristic part of the present invention, will be described in detail below. 12 is a cross-sectional view of the pump casing 12 showing that the cross-sectional area of the flow path 50 in the pump casing 12 starts to decrease within a predetermined range from the volute end portion 52 (XII-XII line in FIG. 1). FIG.

  As shown in FIG. 12, the pump casing 12 is formed so as to surround the impeller 11, and the interval between the side wall 12a of the pump casing 12 and the impeller 11 is from the side of the volute starting portion 51 side. Further, it is formed so as to be larger on the side of the rolling end portion 52. An annular space (a part of the pump chamber 26) formed between the side wall 12 a and the outer periphery of the impeller 11 discharges sewage discharged to the outer peripheral side of the impeller 11 from the pump casing 12. A flow path 50 for discharging from the outlet 24 to the outside of the pump is configured. That is, the flow path 50 is formed in a spiral shape called a volute centering on the impeller 11.

  With such a configuration of the pump casing 12, as described above, the sewage discharged from the impeller 11 is received by the side wall 12a of the pump casing 12, and the discharge port of the pump casing 12 is passed through the flow path 50. Will flow to 24.

  Further, a protruding portion 12b called a tongue portion is formed in the vicinity of the whirling end portion 52 of the pump casing 12 (on the discharge port 24 side of the pump casing 12). The projecting portion 12b is provided so as to distinguish between the whirling end portion 52 side and the whirling start portion 51 side of the volute so that the sewage discharged from the impeller 11 can be removed from the volute end portion 52 side. Thus, the amount flowing to the start portion 51 side (recirculation flow rate for recirculation around the impeller 11) can be reduced.

  Here, the end of whirling of the volute is a position where the direction of the flow path 50 in the pump casing 12 changes from the circumferential direction to the radial direction, and the start of whirling is the position of the end of whispering across the protrusion 12b. This is the opposite position. That is, the starting position of the volute is usually a portion where the distance between the pump casing 12 and the outer periphery of the impeller 11, that is, the width of the flow path 50 is minimized.

  The pump casing 12 is formed such that the width of the flow path 50 gradually decreases from the upstream side toward the downstream side within a predetermined range from the volute end portion 52 of the volute. That is, the cross-sectional area of the flow path 50 gradually decreases from the upstream side to the downstream side in the above-described range.

  In this way, the flow of the volute is compared with that of the conventional structure (the dotted line portion shown in the figure) in which the flow path 50 gradually increases from the volute start portion 51 side toward the finish end portion 52 side. The flow of sewage in the vicinity of the end portion 52 can be made faster, the sewage flowing in the flow path 50 can flow more smoothly to the discharge port 24 side, and the sewage in the vicinity of the sowing end portion 52 of the volute. It is possible to suppress the pressure increase and reduce the pressure difference from the starting portion 51.

  Therefore, it is possible to reduce the recirculation flow rate of the sewage from the whispering end portion 52 side to the whistling start portion 51 side, and foreign matters flowing in the pump are less likely to clog the protruding portion 12b. In particular, since the flow rate of sewage is small and the pressure difference between the whirling end portion 52 and the whirling start portion 51 is large, the permeability can be greatly improved in a low flow rate region where foreign substances are easily clogged.

  Moreover, by reducing only the cross-sectional area of the flow path 50 within a predetermined range from the volute end portion 52 of the volute of the pump casing 12 from the upstream side, the cross-sectional area of the flow path 50 from the volute start portion 51 of the volute is made constant. Compared with the case, the discharge pressure can be increased to some extent, and the pump efficiency is not extremely deteriorated.

  In particular, the point where the cross-sectional area of the flow path 50 starts to decrease is within the range of 30 to 120 degrees (range α shown in FIG. 12) in the circumferential direction from the whirling end portion 52 toward the whirling start portion 51 side. It is more effective when set to.

  Further, by combining with the impeller 11 having good passability and efficiency as described above, it is possible to achieve both the improvement of the passability of foreign matter and the improvement of efficiency in the impeller 11 without deteriorating the pump efficiency. .

(Other embodiments)
In addition, the structure of this invention is not limited to the said embodiment, The other various embodiment is included. That is, in the above-described embodiment, the cross-sectional area of the flow path 50 in the pump casing 12 is gradually decreased from the upstream side toward the downstream side within a predetermined range from the volute end portion 52. Not limited to this, as shown in FIG. 13, the cross-sectional area of the flow path 50 may be substantially constant from the end portion 52 of the volute to a predetermined angle. In this case, it is preferable that the predetermined angle is set within a range of 30 degrees to 210 degrees (range β shown in FIG. 13) in the circumferential direction from the winding end part 52 of the volute toward the starting part 51 side.

  Moreover, in the said embodiment, although the cross-sectional area of the flow path 50 in the pump casing 12 is made to become small gradually toward the downstream from the upstream side, it is not restricted to this, and once the flow path 50 You may make it the cross-sectional area of this flow path 50 become constant in the middle after a cross-sectional area becomes small.

  Furthermore, in the said embodiment, although the impeller 11 which consists of the primary blade | wing 36 which divides and forms the spiral flow path 35, and the secondary blade | wing 38 formed on the outer peripheral surface is used, in this case, Any type of impeller may be used.

  Furthermore, in the said embodiment, although the impeller 11 was installed in the attitude | position which the suction inlet 29 opens vertically downward, the installation attitude | position of the impeller 11 is not limited at all. For example, it is of course possible to place the impeller 11 horizontally so that the suction port 29 faces in the lateral direction. The vertical direction in the above description is a direction for convenience of description, and does not limit the actual installation direction.

  As described above, the present invention is useful particularly in the case of transporting sewage containing impurities and the like in a liquid pump that transports liquid.

It is sectional drawing of the pump for wastewater treatment. It is the perspective view which looked at the impeller from the upper part. It is the perspective view which looked at the impeller from the downward direction. It is a top view of an impeller. It is a D1 direction arrow line view of FIG. It is a D2 direction arrow line view of FIG. It is a D3 direction arrow line view of FIG. It is the VIII-VIII sectional view taken on the line of FIG. It is the IX-IX sectional view taken on the line of FIG. It is the XX sectional view taken on the line of FIG. It is the XI-XI sectional view taken on the line of FIG. It is the XII-XII sectional view taken on the line of FIG. FIG. 13 is a view corresponding to FIG. 12 according to another embodiment.

Explanation of symbols

10 Sewage treatment pump (liquid pump)
DESCRIPTION OF SYMBOLS 11 Impeller 12 Pump casing 12a Side wall 12b Protrusion part 29 Suction port 34 Discharge port 35 Primary flow path (spiral flow path)
36 Primary blade 37 Secondary flow path 38 Secondary blade (blade part)
40 Flange part 50 Flow path (discharge flow path)
51 Beginning part 52 Ending part

Claims (4)

A liquid pump comprising: an impeller that discharges liquid to the outer peripheral side; and a pump casing that surrounds the outer periphery of the impeller and is formed with a volute-shaped discharge passage that sends out the discharged fluid in the circumferential direction. And
The liquid pump is characterized in that the discharge flow path is formed so as to have a portion where the cross-sectional area of the flow path decreases from the upstream side toward the downstream side within a predetermined range from the end of the volute. In claim 1,
The liquid pump is characterized in that the point where the cross-sectional area of the discharge channel begins to decrease is set within a range of 30 to 120 degrees in the circumferential direction from the end of the volute to the start side of the volute. In any one of Claim 1 or 2,
The impeller has a suction port formed on one end side in the rotation axis direction and a discharge port formed on the side on the other end side, and has a spiral shape communicating the suction port and the discharge port inside. It is substantially cylindrical with a flow path formed,
On the outer peripheral surface of the impeller, there is provided a flange portion that protrudes outward over the entire circumference between the suction port and the discharge port, and the outer peripheral surface on the discharge port side of the flange portion. A liquid pump characterized in that a radial flow type vane portion is formed so as to be recessed and communicate with the discharge port and extend in the circumferential direction. A liquid pump comprising: an impeller that discharges liquid to the outer peripheral side; and a pump casing that surrounds the outer periphery of the impeller and is formed with a volute-shaped discharge passage that sends out the discharged fluid in the circumferential direction. And
The discharge channel has a substantially constant cross-sectional area from the end of the volute to the start side of the volute until a predetermined angle in the circumferential direction, and the predetermined angle is set within a range of 30 degrees to 210 degrees. A liquid pump characterized by that.

Images