JPH06288380A - Noise reducing structure of westco pump - Google Patents

Abstract

PURPOSE:To successively moderate the impact sound by the water flow from the groove of an impeller which reaches a discharge passage by an inclined surface by forming the inclined surface inclined by a prescribed angle in the flowing direction of the fluid in a fluid passage on a front surface facing the fluid passage of a partition on the discharge passage side. CONSTITUTION:In an impeller 3, a number of grooves 1 are formed on the outer periphery to constitute vanes 2. On the other hand, a casing 8 has a fluid passage 6 formed so as to cover the grooves 1 by the most part in the circumference of the impeller 3, a sucking passage 4 and a discharge passage 5 formed in a part of the fluid passage 6, and a partition 7 for isolating them formed thereon. In this case, in the front surface facing the fluid passage 6 of the partition 7 on the discharge passage 5 side, the edge part on the side close to the periphery of the impeller 3 is protruded to the outer circumferential direction of the impeller 3 by a prescribed distance in the direction reversed to the rotating direction of the impeller 3. An inclined surface 10 inclined by a prescribed angle to the flowing direction of the fluid is formed in the fluid passage 6. Thus, the impact sound by the water flow is successively moderated by the inclined surface, and the water smoothly flows.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for reducing the noise of a Wesco pump, which is widely used as a water supply pump for small boilers, a water supply pump for household shallow wells, and the like, especially at high frequencies.

[0002]

2. Description of the Related Art As a water supply pump for a small boiler, a water supply pump for a domestic shallow well, etc., a pump having a high head and a small flow rate is preferable. Is used.

As shown in FIGS. 4 to 7, the above-mentioned Westco pump has an impeller (3) in which blades (2) are formed by a large number of grooves (1) on the outer peripheral edge, and an impeller (3) of this impeller (3). groove
(1) An annular fluid passage (6) having a predetermined cross-sectional shape (substantially rectangular in the illustrated example) is formed so as to cover the portion, and a part of this fluid passage (6) is formed into a partition wall (7). It is constituted by a casing (8) which is cut off by and is formed with a suction flow path (4) and a discharge flow path (5) at both ends thereof.

The operation principle will be briefly described. The water flowing out of the groove (1) with the rotation of the impeller (3) gains angular momentum, and the water inside the casing (8) flows from the outer circumference of the impeller (3). After flowing out into the passage (6) and exchanging momentum with the liquid in the fluid passage (6), it again flows into the root of the groove (1). Such an action is repeated in each groove (1), and the fluid is discharged through the spiral path to generate a high pressure despite its small size. The partition between the suction flow path (4) and the discharge flow path (5)
(7) prevents the high-pressure fluid on the discharge channel (5) side from flowing back to the suction channel (4).

Such a wasteco pump has the following problems. That is, the impeller (3) in the casing (8) is surrounded by the fluid passage (6) at the periphery of the impeller (3).
Water flowing out of the groove (1) of (3) flows out in the circumferential direction at high speed, and counters the pressure gradient in the circumferential direction. And the fluid passage
The water flowing out at the end of (6) is blocked by the partition wall and is discharged into the discharge channel.
Go to (5). This water continuously flows out to the impeller (3), but when viewed from the stationary partition wall (7),
The impeller (3) vane (2) and the water flow channel (1) alternate, so they are periodically impacted by the water (the number of vanes). The noise corresponding to x (the number of rotations of the impeller) and the nth harmonic of the frequency that is an integral multiple of this frequency are generated. Actually this noise is
It is a metallic high-pitched sound and a very offensive noise.

When such a pump is used for a well, it is very annoying to the neighborhood especially when the pump is operated at midnight. On the other hand, when used as a water supply pump for boilers, a multi-can installation system for small boilers that have been especially prized in recent years (using multiple small boilers instead of one large boiler, In a system that activates a small boiler, which can shorten the steaming waiting time and improve the operating efficiency.), Since many pumps are used, the noise is doubled and becomes significant.
Therefore, expensive multi-stage turbine pumps are currently used.

The above-mentioned noise has become a serious problem in terms of improving the commercial characteristics of the Westco pump, and various measures for reducing such noise have been proposed so far.
For example, "The phase of the blades on the left and right of the center plane of the impeller is shifted by a half pitch, and the collision of the fluid on the partition walls is averaged to reduce noise. "," A part of the partition wall where the outer periphery of the impeller contacts the partition wall is cut into a wedge shape to create a cavity that absorbs the impact of the jet flow flowing out from the blade. , Etc., each of which has a slight effect, but it is still insufficient.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a noise reduction structure for a Wesco pump that reduces high-frequency impact noise due to pulsating flow in a fluid passage.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an impeller having blades formed by forming a large number of grooves on the outer peripheral edge and most of the circumference of the impeller. A fluid passage is formed so as to cover the groove portion in a portion, a suction passage and a discharge passage are formed in a part of the fluid passage, and a casing having a partition formed to separate the two passages from each other is used. In the pump, a front surface of the partition wall on the side of the discharge flow path facing the fluid passage has an edge portion on the side close to the peripheral edge of the impeller in a direction opposite to the rotation direction of the impeller with respect to the circumferential direction of the outer circumference of the impeller. A noise reduction structure for a wesco pump, characterized in that the noise reduction structure is formed at a projecting position by a predetermined distance to form an inclined surface inclined at a predetermined angle with respect to the flow direction of the fluid in the fluid passage. A.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the noise reduction structure according to the present invention is applied to the wesco pump shown in FIGS.
This will be described with reference to FIG. In FIGS. 1 and 2, the same components as those in FIGS. 4 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the embodiment shown in FIGS. 1 and 2, the suction channel
The partition wall (7) provided between (4) and the discharge flow path (5) is located on the front surface on the discharge flow path (5) side with respect to the flow direction of the fluid in the fluid passageway (6). An inclined surface (10) forming a predetermined angle is formed. More specifically, the inclination direction of the inclined surface (10) is
The edge of the inclined surface (10) close to the outer peripheral edge of the impeller (3) projects a predetermined distance in the direction opposite to the rotation direction of the impeller (3) with respect to the circumferential direction of the outer circumference of the impeller (3). Due to this inclined surface (10) in the position, the fluid flowing through the fluid passageway (6) smoothly flows into the discharge flow passage (5).

Further, in this embodiment, a part of the inner wall surface (5 ') of the discharge flow path (5) is formed so as to be smoothly continuous with the inclined surface (10). In the example,
The wall surface (5 ') is formed so as to be flush with the inclined surface (10). In addition, it is preferable that the wall surface on the downstream side of the inner wall surface (5 ') of the discharge flow passage is also formed so as to be smoothly continuous with the inner wall surface (5') for further improvement of the noise reduction effect described later. Is. By doing so, the fluid from the fluid passageway (6) is gradually diverted from the tangential direction of the impeller (3) by the inclined surface (10), and then it becomes smoother along this direction. Since it flows toward the discharge flow path (5), further noise reduction can be achieved. The reference numeral (20) in the figure indicates a connecting portion of the discharge flow path (5) at the terminal end to an external device.

The operation of the above structure will be described.
As described above, the water sucked into the fluid passageway (6) from the suction passageway (4) passes through the fluid passageway (6) along with the rotation of the impeller (3) in a spiral path while increasing the pressure. To be distributed. At the end of the fluid passage (6), the water flowing out from between the grooves (1) is blocked by the partition wall (7) and goes to the discharge flow path (5).

At this time, the water flowing out from each groove (1) of the impeller (3) collides intermittently with the stationary partition wall (7) as described above, and its direction is changed. Discharge channel
According to the noise reduction structure according to the present invention, the water flowing out from the groove (1) is discharged smoothly from the groove (1) without the flow direction of the water being suddenly changed by the inclined surface (10). Since it flows toward the connecting portion (20) at the end of the flow path (5), noise due to fluctuations in water pressure can be reduced. That is, each groove (1)
The energy of noise generated by the intermittent impingement of water flow from the partition wall (7) is 2 [pressure per unit area exerted by the water from each groove (1) on the inclined surface (10)]. Since it is proportional to the power and the area on which the pressure acts, an inclined surface (10) is provided as in the present invention, and the discharge flow path (5) is further provided with an inclined surface (10) of the partition wall portion (7). By being formed so as to be smoothly continuous along, the pressure per unit area can be significantly reduced, and the above-mentioned noise generation can be effectively prevented.

Further, FIG. 3 shows another embodiment of the present invention, in which the inclined surface (10) is extended to a part of the inner wall surface (5 ') of the discharge flow path (5). Instead, it is formed only on the front surface of the partition wall (7). Generally, in such a Wesco pump, the partition wall (7) is often assembled as a separate component from the casing (8) (see FIGS. 4 to 6).
reference). For example, the casing (8) is composed of the casing (8) main body and a liner (30) fixed to the inner surface of the casing (8), and the fluid passage (6) is provided around the outer periphery of the liner (30) when the pump is completed.
To form a thin wall portion, and a partition wall portion on a part of the outer periphery thereof.
An example is a structure in which an axial protruding portion (7) is formed. With such a structure, it is possible to obtain the above-described excellent noise reduction effect by changing only the partition wall portion (7) of the liner (30), and to suppress the cost increase against the effect at an extremely low cost. You can

[0016]

As described above, in the noise reduction structure for a wasteco pump according to the present invention, the front surface of the partition wall on the discharge flow passage side facing the fluid passage has the edge portion on the side close to the peripheral edge of the impeller. By forming the protrusion at a predetermined distance in the direction opposite to the rotation direction of the impeller with respect to the circumferential direction of the outer circumference of the impeller, the inclined surface is inclined at a predetermined angle with respect to the flow direction of the fluid in the fluid passage. Because I did
The impact sound due to the water flow from the groove of the impeller reaching the discharge flow path is gradually reduced by the inclined surface, and this water flow smoothly flows in the discharge flow path without suddenly changing its direction. In addition, it is possible to effectively prevent the generation of the noise as described above even in the discharge passage, and it is possible to effectively prevent the generation of the impact noise due to the high frequency as in the conventional case.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a wasteco pump to which the present invention is applied.

FIG. 2 is an enlarged view of a main part of the embodiment of the Westco pump shown in FIG.

FIG. 3 is a vertical sectional view of another embodiment of the Westco pump to which the present invention is applied.

FIG. 4 is a vertical sectional side view showing an example of a conventional Westco pump.

5 is a cross-sectional view taken along the line I′-I ′ of FIG.

FIG. 6 is a sectional view taken along line II′-II ′ of FIG.

FIG. 7 is a sectional view taken along line III′-III ′ of FIG.

[Explanation of symbols]

 (1) Groove (2) Blade (3) Impeller (4) Suction flow path (5) Discharge flow path (5 ') Discharge flow path wall surface (6) Fluid passage (7) Partition wall (8) Casing (10) Slope

Claims (1)

[Claims] 1. An impeller (3) having blades (2) formed by forming a large number of grooves (1) on an outer peripheral edge, and a groove (1) part in most of the circumference of the impeller (3). A fluid passageway (6) is formed so as to cover the suction passageway (4) and a discharge passageway (5) in a part of this fluid passageway (6). In a wasteco pump comprising a casing (8) having a partition wall (7) separating the partition (5), the front surface facing the fluid passage (6) of the partition wall (7) on the discharge flow channel (5) side is By forming an edge portion on the side close to the peripheral edge of the impeller (3) at a predetermined distance protruding position in a direction opposite to the rotation direction of the impeller (3) with respect to the circumferential direction of the outer circumference of the impeller (3), A noise reduction structure for a wesco pump, characterized in that it is formed on an inclined surface (10) inclined at a predetermined angle with respect to the flow direction of the fluid in the fluid passageway (6).