KR950009353B1 - Vertical type pump - Google Patents

Abstract

No content.

Description

Vertical shaft pump

1 is a cross-sectional view of a pump bowl part showing an embodiment of the present invention.

2 and 3 are diagrams illustrating the vibration mode of the vertical shaft pump due to the water level fluctuation, respectively.

4 is a sectional view of a pump bowl showing a modification of the present invention.

5 is a V-V perspective view of FIG.

6 to 9 show another embodiment of the present invention, 6 to 8 are cross-sectional views of the pump bowl, respectively. 9 is an overall front view of the vertical shaft pump.

* Explanation of symbols for main parts of the drawings

1: impeller 2: casing liner

3: suction bell mouse 4: pump casing

5 intake hole 6 intake pipe

7: damping body 8: rectifying plate

9: fixed plate 10: strainer

11: plate 12: support

The present invention relates to a vertical shaft pump installed in the absorption tank, and in particular, to enable the pumping operation even when the water level in the absorption tank is lowered, for example, to carry out the preliminary standby operation is installed to drain the water discharge during rain, The present invention relates to a vertical shaft pump that can also be used for the management operation of the pump.

In recent years, as the urbanization progressed, the inflow into the rainwater drainage pumping station rapidly increased due to the increase of the rainwater impermeable area. For this reason, in the case of rainfall, the advance standby operation type | mold vertical pump which operates a pump in the state in which the pump well level is lower than the prescribed level by predicting the inflow amount and arrival time to a pump station in advance is becoming practical.

This type of conventional vertical shaft pump is equivalent to the lowest water level (LWL) that sucks in air when the water level is lower when the pump is submerged, as described in Japanese Patent Laid-Open No. 63-90697. When the impeller is installed at a position slightly higher than the pump specific water level, and the water level is lower than the water level corresponding to the lowest water level, the pump is idle due to vacuum breakdown, so that the water can not be drained and drained. There is one thing.

As another conventional vertical shaft pump, as described in Japanese Patent Application Laid-Open No. 63-150097, the impeller is positioned at a lower level than the absorption tank level, and a through hole communicating with the outside is provided near the inlet of the impeller. It is known that the through-hole is connected to the pipe, and the other end of the pipe is provided with an opening near the level where the impeller in the absorption tank is submerged.

Moreover, as another conventional example, there exist some described in Unexamined-Japanese-Patent No. 2-4993. This is because when the pump is operating in the air, the bearing part becomes unwatered and the vertical shaft pump may vibrate. Therefore, in order to prevent the vibration, a large disk-shaped vibration damper is installed on the pump spindles above and below the bearing to prevent vibration of the shaft. In some cases, the shaft is pressed against the bearing by the centrifugal force of the vibration isolator to suppress vibration.

In general, the preliminary standby operation based on rainfall information or the like increases the storage effect of the absorption tank and the conduit, so that drainage operation at the lowest water level is preferably possible, and it is appropriate to the level of the absorption tank. It is effective to prevent the vortex or reduce the surge in the absorption tank, so that the pump can be operated stably.

However, in the prior art, Japanese Patent Application Laid-Open Nos. 63-90697 and 2-2293 have no consideration for drainage operation at a water level lower than the lowest water level, for example, its diameter is 1.4 from the suction port of the suction bell mouse. The drainage operation is not performed at a water level lower than the known minimum water level, which is from 1.7 times to 1.7 times.

According to the above-described prior art small 63-150097, when the water level of the absorption tank is lower than the level of the opening, air is sucked in from the opening and the pumping action of the pump is gradually lowered. It is characterized in that the pumping operation becomes possible and the transition to the idle state does not occur abruptly. For example, it is considered that it is suitable for the pump which performs what is called a preliminary standby operation which idles and waits for a pump before a sudden inflow into an absorption tank arises.

In this type of vertical pump, as the water level in the absorption tank is lowered, the amount of intake from the through-hole provided in the suction bell mouse is increased to lower the amount of drainage. However, it is difficult to perform the drainage operation with stable intake, and Due to the volume unbalance between air and water, the unbalance force is larger than that of a conventional pump. In addition, at the time of drainage operation with intake air, the water level is considerably lower than at the normal drainage operation of the pump. Therefore, the part where the pump casing is submerged in water is reduced, so that vibration damping property is lowered. Accordingly, it has been found that in the intake operation, if stable intake is not performed, there is a problem that vibration occurs due to the volume unbalance of air and water in the impeller and the damping of the pump. In particular, when the natural frequency of the pump is close to the rotational speed of the pump, there is a problem that a very large vibration occurs due to resonance.

An object of the present invention is to obtain a vertical shaft pump capable of suppressing vibration generated during intake operation in which drainage operation is performed while intake is intake.

Another object of the present invention is to obtain a vertical pump that can adjust the natural frequency of the pump so that the natural frequency of the pump does not resonate with the rotational speed of the pump in order to suppress the vibration generated during the intake operation to perform the drain operation while intake .

In order to achieve the above object, the vertical shaft pump of the present invention includes an impeller of a pump installed at a lower side than a position corresponding to the lowest water level to suck air from the suction bell mouse of the pump casing below the water level during the pump operation; An intake hole provided in the pump casing at a lower side than the impeller, an intake pipe connected at one end thereof to the intake hole, and open at the other end to the air at a level higher than the highest level of the pump absorption tank, and the pump casing. And a vibration damping body which is provided below the intake hole and acts as a resistance to water in the absorption tank.

Another feature of the present invention is that the impeller of the vertical shaft pump is located below the position corresponding to the lowest water level at which the water level during the pump operation is lower than the lowest water level to suck air from the suction bell mouse of the pump casing. An intake hole is provided in the pump casing on the lower side, an intake pipe whose one end is connected to the intake hole and the other end is open to the air, and the inside thickness of the intake bell mouse is It is located on the vertical shaft pump thicker than the inner thickness.

Another feature of the present invention is that the impeller of the pump is located on the lower side than the position corresponding to the lowest water level to suck the air from the suction bell mouse below the water level during the pump operation, the lower side than the impeller An intake hole is provided in the pump casing, one end of the intake pipe is connected to the intake hole, and the other end thereof is opened to the atmosphere at a level higher than the highest level of the pump absorption tank, and the thickness of the suction bell mouse is There is a vertical pump to adjust the natural frequency of the suction bell mouse by greater than the thickness of the casing.

Another feature of the present invention is that the impeller of the pump is located on the lower side than the position corresponding to the lowest water level to suck the air from the suction bell mouse below the water level during the pump operation, the lower side than the impeller An intake hole is provided in the pump casing, one end of the intake pipe is connected to the intake hole, and the other end thereof is opened to the atmosphere at a level higher than the highest level of the pump absorption tank, and a plurality of plates are placed on the suction bell mouse. In the vertical pump to adjust the natural frequency of the suction bell mouse.

Another feature of the present invention is that the impeller of the pump is located on the lower side than the position corresponding to the lowest water level to suck the air from the suction bell mouse below the water level during the pump operation, the lower side than the impeller An intake hole is provided in the pump casing, one end of the intake pipe is connected to the intake hole, and the other end thereof is opened to the atmosphere at a level higher than the highest water level of the pump absorption tank, and is installed in the suction bell mouse. In the vertical pump to adjust the natural frequency of the suction bell mouse by modifying the number and thickness of the.

According to this invention, it operates as follows by the said structure.

Since the vibration damping body is installed below the intake hole, the vibration damping body is always immersed in water even during the intake operation which tends to generate vibration. Therefore, when the pump body vibrates, the vibration damping body also vibrates at the same time and receives a large resistance of water, thereby causing a vibration damping action. Therefore, the effect which suppresses the pump vibration which arises at the time of intake operation by a damping body is acquired.

Moreover, since the said damping body is provided with the rectifying plate which rectifies the water which flows into an impeller, the flow which flows in into an impeller inlet is stabilized and it prevents the generation of an unbalanced force, It is possible to reduce the generation, and to achieve a lower vibration vertical shaft pump.

Again, the vibration damping body is provided with a strainer of water flowing into the impeller to suppress vibration and at the same time remove waste.

In addition, the vibration damping body is constituted by a plurality of dividable members, so that the natural frequency of the lower part of the pump casing can be adjusted, and even if the natural frequency of the pump body decreases due to the water level drop in the water storage tank, it is possible to prevent resonance from occurring. There is a number.

In addition, resonance can be avoided by changing the natural frequency of the suction bell mouse by means of increasing the thickness of the suction bell mouse to increase its weight or by changing the number of intake pipes provided in the pump casing.

An embodiment of a vertical shaft pump of the present invention will be described below with reference to the drawings.

1 is a cross-sectional view showing an embodiment of the present invention, the structure of the bowl (Bowl) of the preceding standby vertical shaft pump. The suction bell mouse 3 of the pump casing is connected to the lower side direction of the casing liner 2 of the pump casing 4 in which the impeller 1 is accommodated.

An intake hole 5 is provided near the lower side of the impeller 1, an intake pipe 6 is provided in connection with the intake hole 5, and an intake air amount adjustment valve (not shown) at the other end of the intake pipe 6. ) Is installed to form the flow control device.

In addition, a plurality of vibration damping bodies 7 are provided in the bell mouth 3 so as to be located from the vicinity of the intake hole 5 to the lower portion, and act as a resistance to water in the absorption tank to suppress vibration.

When the water level of the absorption tank is lowered and the water level when the pump is submerged is lower than or equal to the lowest water level (LWL) at which air is sucked in, the intake hole 5 becomes negative pressure and is adjusted to the intake operation state. . That is, when the water level is lower than the lowest water level LWL, air is sucked in from the intake hole 5 and the inside of the impeller 1 is in an intake operation state in which water and air are mixed flows. For this reason, the unbalance force becomes large. In the conventional pump, the portion submerged in water during this intake operation decreases, and the resistance to water decreases, so that the vibration easily occurs. On the other hand, in the present invention, even when the vibration damping body 7 is submerged in the water at the lowest water level (LWL), the resistance against water is large and water acts as a buffer material, so that the vibration damping effect is generated, so that the unbalanced force is somewhat different. Even if it becomes large, vibration can be suppressed.

This is because, as shown in Figs. 2 and 3, when the underground part of the vertical shaft pump (below the pump installation position) vibrates in the primary mode, when the water level is lowered and the length (l) of the water submerged part of the pump decreases, The damping effect due to the resistance of the water to the vibration of the damper effect is reduced. For this reason, vibrations tend to occur and amplitude increases. In order to prevent this, in the present embodiment, the vibration is reduced by providing a resistor (vibration damping member) against vibration in the water in the submerged portion of the pump casing lower side.

This damping body is not about the size of a simple rib necessary for the strength of the bell mouse, and as shown in FIG. 1, a dimension of 1.5 to 2 times or more of the diameter of the intake hole 5 portion of the bell mouse is required.

4 and 5 show a modification of the embodiment of FIG. 1 of the present invention, wherein the vibration damping body 7 is installed on the lower side of the suction bell mouse 3, and the vibration damping body 7 is provided with an impeller. The embodiment provided with the rectifying plate 8 for rectifying the incoming water is shown. As shown in Fig. 5, the rectifying plate 8 is arranged in a cross shape, supported by four posts 7a, and provided on the bell mouse 3 by a plurality of mounting plates 9.

When the water level is lowered and intake is started, the flow of the impeller inlet is not necessarily constant, and it is disturbed depending on the suction conditions, and the vibration is increased due to instability of air intake and unbalance of capacity of water and air in the impeller.

In this embodiment, since the vibration damping body which has the rectifying plate 8 is provided in the lower part of the bell mouth 3, the flow of the vicinity of an impeller inlet is rectified and the intake amount is stabilized and vibration can be reduced.

This vibration effect is confirmed by model tests.

In the vibration damping body having the rectifying plate 8 as in the above embodiment, when the pump vibrates, it becomes a resistance to water, thereby also reducing the vibration.

In addition, compared to the conventional pump, the air pump of the vertical standby operation type has a wider operating range and a wider range of maximum and minimum water levels. The frequency will change. For this reason, the rotational speed and the natural frequency tend to coincide with those of the conventional pump, and when there is an overlap between the unbalanced force at the time of air suction, there is a possibility that the vibration is increased. In the present invention, since the vibration damping body 7 is made of a plurality of members, for example, the weight is changed by changing the number of the fixed plates 9 or by changing the number and thickness of the posts 7a, thereby increasing the natural frequency. Adjust to avoid resonance. In addition, in the present embodiment, the rectifying plate 8a is also provided inside the bell mouth 3 so that the rectifying and vibration suppressing effects of the impeller inlet can also be obtained, thereby further improving the vibration reducing effect.

6 is an embodiment in which the damper 7 has a strainer 10 of water flowing into the impeller. The strainer 10 is provided below the bell mouth 3. In this embodiment, at the pumping station with many wastes, the wastes are removed and at the same time, the vibration resistance is reduced by the resistance of the water in the strainer 10 portion to reduce vibration.

In the embodiment shown in Figs. 7 and 8, both of the weights on the suction side are changed to avoid resonance.

7 adjusts the natural frequency by increasing the weight of the bell mouth 3 to increase its weight.

8 is to adjust the natural frequency by placing a plurality of plates 11 on the bell mouse 3 to adjust the weight.

FIG. 9 is an overall view of a vertical shaft pump showing still another embodiment of the present invention, and is configured so that a plurality of intake pipes 6 can be fixed to the bell mouth 3 and the support 12. The intake pipe 6 is provided with a different thickness so that the natural frequency of the pump basement portion is changed by the intake pipe. Therefore, by changing the number or thickness of the intake pipes 6, it is possible to adjust the natural frequency by changing the stiffness and weight of the bell mouse, thereby reducing vibration by avoiding resonance. In addition, it is also possible to always apply a tensile force to the intake pipe 6 and to adjust the natural frequency in accordance with the magnitude of the tensile force by providing a plurality of intake pipes in the circumferential direction of the bell mouth.

As described above, according to the present embodiment, even in the lowest water level (LWL), the vibration damping body is present in the part submerged in water, and the unbalance at the time of intake can be reduced by using a structure that also serves as a rectifying plate. Therefore, vibration can be reduced in the entire operating range of the vertical standby pump.

In addition, since the natural frequency can be changed by means of adjusting the weight of the suction bell mouth or providing a plurality of intake pipes, resonance can be avoided, so that vibration generation factors can be reduced.

According to the present invention, since the vibration damping body is provided below the intake hole provided in the pump casing, the vibration damping body is immersed in water even during the intake operation in which drainage operation is performed while intake, so that the pump vibration generated at the intake operation is prevented. There is an effect that can be suppressed by the body.

In addition, by changing the weight and rigidity of the suction bell mouse so that the natural frequency thereof can be changed, the vibration generated during the intake operation can be prevented from increasing due to resonance.

Claims (9)

If the water level during the pump operation is less than that, the impeller installed on the lower side than the position corresponding to the lowest water level to suck air from the suction bell mouse of the pump casing, and the intake hole provided on the pump casing on the lower side than the impeller. And an intake pipe whose one end is connected to the intake hole and the other end thereof is opened to the atmosphere at a level higher than the highest water level of the pump absorption tank, and installed in the pump casing and located below the intake hole to provide water in the absorption tank. And a vibration damper acting as a resistance against the vertical shaft pump. The vertical shaft pump according to claim 1, wherein the vibration isolator is provided in a suction bell mouse of the pump casing. The vertical shaft pump according to claim 2, wherein the vibration damping body is provided on a lower side of the suction bell mouse and has a rectifying plate for rectifying water flowing into the impeller. 3. The vertical shaft pump according to claim 2, wherein the vibration damper includes a strainer of water flowing into the impeller, and the strainer is resistant to water when the pump vibrates to suppress vibration of the pump. The vertical shaft pump according to claim 1, wherein the vibration damping body is constituted by a plurality of dividable members to prevent the resonance by changing the weight of the vibration damping body. If the water level during the pump operation is less than that, place the impeller of the vertical shaft pump below the position corresponding to the lowest water level where air is sucked from the suction bell mouse of the pump casing, and intake into the pump casing below the impeller. A hole is provided, and an intake pipe having one end connected to the intake hole and the other end open to the atmosphere, and the thickness of the suction bell mouse is made thicker than the inner thickness of the pump casing other than the suction bell mouse. Vertical pump. If the water level during the pump operation is lower than that, the impeller of the pump is located on the lower side than the position corresponding to the lowest water level to suck air from the suction bell mouse, and the intake hole is provided in the pump casing on the lower side than the impeller. One end of the intake pipe is connected to the intake hole, and the other end thereof is opened to the atmosphere at a level higher than the highest level of the pump absorption tank, and the thickness of the suction bell mouse is larger than the thickness of the pump casing. Vertical shaft pump, characterized in that for adjusting the natural frequency of the suction bell mouse. If the water level during the pump operation is lower than that, the impeller of the pump is located on the lower side than the position corresponding to the lowest water level to suck air from the suction bell mouse, and the intake hole is provided in the pump casing on the lower side than the impeller. One end of the intake pipe is connected to the intake hole, and the other end thereof is opened to the atmosphere at a level higher than the highest level of the pump absorption tank, and the suction bell mouse is placed on the suction bell mouse so that a plurality of plates are placed. Vertical shaft pump, characterized in that to adjust the natural frequency of. If the water level during the pump operation is lower than that, the impeller of the pump is located on the lower side than the position corresponding to the lowest water level to suck air from the suction bell mouse, and the intake hole is provided in the pump casing on the lower side than the impeller. One end of the intake pipe is connected to the intake hole, and the other end thereof is opened to the atmosphere at a level higher than the highest level of the pump absorption tank, and the number and thickness of the intake pipes installed in the suction bell mouse are modified. Vertical shaft pump, characterized in that for adjusting the natural frequency of the suction bell mouse.