JP6340262B2 - Pump damping device - Google Patents

Description

  The present invention relates to a vibration control device for a pump that drains water stored in a suction water tank.

  In the building where the pump is installed, a suction water tank is formed in the lower part of the installation floor, and a pump chamber is formed in the upper part of the installation floor. The vertical pump includes a casing that extends vertically from the pump chamber through the arrangement hole of the installation floor. In the casing, a suction port is formed on the lower end side located in the suction water tank. The casing is provided with a main shaft to which an impeller is fixed, and a driving means (motor) is connected to the main shaft.

  The pump structure including the installation floor (building) and the pump is individually balanced in consideration of the state of the installation floor on the site where the installation is to be performed so that vibration does not occur during operation. However, the vibration caused by the variation in the rigidity of the actual installation floor of the building cannot be denied. In view of this, the vertical shaft pump disclosed in Patent Document 1 is provided with a base member in an arrangement hole of the installation floor, and a casing is fixed to the base member with two-point support, thereby preventing a resonance phenomenon, and vibration and installation of the vertical shaft pump. Suppressing floor damage.

  However, the vertical shaft pump of Patent Document 1 does not take any measures against vibration caused by an unexpected earthquake. In particular, long-period (low-frequency) ground motions that oscillate with a long period are difficult to attenuate, and the amplitude is increased by resonating (or resonating) the building, causing a problem of damaging the pump structure.

JP 2003-161285 A

  It is an object of the present invention to provide a vibration control device for a pump that can suppress vibration due to operation and earthquake and prevent damage to the pump structure.

The pump vibration control device according to the first aspect of the present invention is a pump vibration control device including a casing extending vertically in the suction water tank through an arrangement hole in the installation floor, wherein the casing is located in the suction water tank. together provided et the the outer periphery of the two or more connection portions formed, a liquid flow path for fluidly containing a liquid therein, disposed in the liquid flow path, the flow of liquid in the liquid flow path The liquid flow resistance part to suppress, and the gas flow path where the lower end was connected to each connection part of the liquid flow path, and the upper end side was mutually connected .

The pump vibration control device according to the second aspect of the present invention is a pump vibration control device including a casing extending vertically in the suction water tank through an arrangement hole in the installation floor, wherein the casing is located in the suction water tank. A liquid flow path that is provided in an outer peripheral portion of the liquid flow path and accommodates a liquid in a flowable manner therein, and a liquid flow resistance section that is provided in the liquid flow path and suppresses the flow of the liquid in the liquid flow path, The liquid flow path includes first and second liquid flow paths that are partitioned out of communication with each other.
  In the second aspect, at least one of the first and second liquid flow paths has two or more connecting portions, a gas flow in which the lower ends are connected to the connecting portions and the upper ends communicate with each other. A road may be further provided.

Since the damping device of these aspects is provided with the liquid flow path which accommodated the liquid in the outer peripheral part of the casing, it can give a natural frequency to a liquid so that a long-period seismic motion may be suppressed. Due to the dynamic vibration absorber effect of the liquid channel, vibration applied to the pump structure including the pump and the installation floor can be reduced. Further, the liquid flow resistance portion is provided in the liquid flow path, and the flow resistance of the liquid in the liquid flow resistance portion serves to attenuate (absorb) the vibration, so that the vibration applied to the pump structure can be further reduced. Moreover, since the pump weight is increased by the liquid contained in the liquid flow path, it is possible to counter the excitation force caused by the earthquake. Moreover, since the lower part of the liquid flow path is immersed by the liquid stored in the suction water tank, the vibration can be further reduced by generating the viscous force and additional mass of the liquid. Therefore, damage to the pump structure can be prevented. Moreover, in the 1st aspect, the vibration added to a pump structure can be reliably reduced with the fluid which included gas in the liquid. In the second mode, since the natural frequency of the first liquid channel and the natural frequency of the second liquid channel can be set to be different, a wide range of long-period ground motion can be suppressed.

In the first aspect and the second aspect, it is preferable that an airflow resistance portion that suppresses a gas flow is provided in the gas flow path. In this way, the vibration energy can be absorbed by the flow resistance of the gas at the airflow resistance portion, so that the vibration can be further reduced.

The liquid flow path has two or more vertical pipes extending along the axis of the casing, and a horizontal pipe communicating the lower end side of each vertical pipe. The U-shaped liquid flow path can reliably suppress the vibration of the casing by the swing of the liquid column extending from one vertical pipe to the other vertical pipe through the horizontal pipe. Moreover, by setting the position of the vertical pipe, it is possible to prevent the occurrence of an air suction vortex extending from the water surface of the liquid in the suction water tank to the suction port of the casing. In the case of the first aspect, the connection portion of the liquid channel is the upper end of the vertical pipe. In this case, since a closed circuit in which the liquid and the gas can flow is formed by the gas flow path, the set liquid amount in the liquid flow path can be maintained and vibration can be reliably reduced.

Or the said liquid flow path has two or more vertical piping extended along the axis line of the said casing, and the lower end of each said vertical piping is open | released in the said suction water tank. Thus, vibration applied to the pump structure can be reliably reduced even with a plurality of straight tubular liquid channels communicating with each other via the suction water tank. Further, since the structure of the vibration control device can be simplified, the assembly workability can be improved. Moreover, by setting the position of the vertical pipe, it is possible to prevent the occurrence of an air suction vortex extending from the water surface of the liquid in the suction water tank to the suction port of the casing.

  In the case of the second aspect, the first and second liquid channels may be combined with a U-shaped liquid channel having a different distance from the casing axis to the vertical pipe, or a U-shaped liquid flow may be combined. A path and a straight liquid channel may be combined.

The lower end of the straight pipe communicating with the suction aquarium vertical pipe is set to be lower than the minimum level of the liquid reserved in the suction water tank. If it does in this way, it can suppress reliably that a casing vibrates by rocking | fluctuation of a liquid column, maintaining the accommodation state of the liquid in vertical piping.

The upper end of the vertical pipe is set higher than the maximum level of the liquid reserved in the suction water tank. In particular, in the U-shaped liquid flow path, when the liquid in the suction water tank enters from the upper end of the vertical pipe, the amount of liquid in the liquid flow path increases, so the set natural frequency changes. Therefore, the dynamic vibration absorber effect of the liquid flow path for reducing the vibration of the pump structure may be reduced. However, such a problem can be reliably prevented by setting the upper end of the liquid flow path higher than the water surface of the suction water tank.

  The vibration control device for a pump according to the present invention can have a natural frequency that suppresses long-period seismic vibrations by a liquid flow path containing liquid, and the pump and the installation floor are separated by the dynamic vibration absorber effect of the liquid flow path. The vibration applied to the pump structure including it can be reduced. In addition, since the liquid flow resistance portion is provided in the liquid flow path, the liquid flow resistance acts to attenuate (absorb) vibration, and vibration applied to the pump structure can be further reduced. Therefore, damage to the pump structure can be prevented.

Sectional drawing which shows the damping device of the pump of 1st Embodiment of this invention. Sectional drawing which expanded a part of FIG. The AA line expanded sectional view of FIG. The BB line expanded sectional view of the liquid channel of FIG. Schematic of the vibration damping device of the first embodiment. Schematic of the damping device of the modification of 1st Embodiment. Sectional drawing which shows the damping device of the pump of 2nd Embodiment. Schematic of the damping device of 2nd Embodiment. Schematic of the damping device of the modification of 2nd Embodiment. Sectional drawing which shows the damping device of the pump of 3rd Embodiment. Schematic of the damping device of 3rd Embodiment. Schematic of the damping device of the modification of 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows a vertical shaft pump 10 provided with a vibration control device 26 according to a first embodiment of the present invention. The vertical shaft pump 10 includes a casing 11 that is inserted into the installation floor 2 of the building from above and is fixed so as to extend vertically in the lower suction water tank 5. The vibration control device 26 of the present invention is disposed on the outer peripheral portion of the casing 11 that is generally located in the suction water tank 5, suppresses vibrations and long-period ground motions during normal operation, and includes the installation floor 2 and the vertical pump 10. Prevents damage to the object 1.

  The casing 11 of the vertical shaft pump 10 is provided with a straight tubular pumping pipe 12 arranged through the arrangement hole 3 from the upper pump chamber 4 of the installation floor 2 to the lower suction water tank 5. An impeller case 13 is disposed on the lower end side of the pumping pipe 12, and a suction bell mouth 14 that gradually increases in diameter downward is disposed on the lower end of the impeller case 13. The suction port 15 at the lower end of the suction bell mouth 14 is disposed to face the bottom wall 6 of the suction water tank 5 with a predetermined distance. A discharge bend 16 curved at 90 degrees is disposed at the upper end of the pumping pipe 12 so as to change the flow of water from the vertical direction to the horizontal direction. The discharge bend 16 is disposed in the pump chamber 4. A fixing flange portion 17 for fixing around the arrangement hole 3 on the upper surface of the installation floor 2 is provided below the discharge bend 16. A discharge pipe 18 connected to a downstream discharge water tank (not shown) is connected to the outlet of the discharge bend 16.

  A main shaft 19 that extends in the vertical direction along the axis of the pumped water pipe 12 is disposed inside the casing 11. The main shaft 19 is rotatably supported in the pumped water pipe 12 by bearings 20A to 20D. The lower end of the main shaft 19 passes through the impeller case 13 and is rotatably supported by a bearing 20C located in the suction bell mouth 14. An impeller 21 is fixed to the lower end side of the main shaft 19 located in the impeller case 13 and is rotatably supported by the bearing 20D. A driving machine 22 is connected to the upper end of the main shaft 19 protruding from the discharge bend 16 to the outside of the casing 11. As the drive machine 22, an electric motor or an internal combustion engine can be used. In the case of using an electric motor, a water-resistant (underwater) motor in which a rotor and a stator are watertightly arranged in a motor casing is preferable.

  In the suction bell mouth 14 of the present embodiment, an axial bell mouth 23 integrally formed with an underwater vortex prevention rib 25 is disposed. The axial center bell mouth 23 is made of a resin such as FRP (fiber reinforced plastic) and has a conical cylindrical shape extending along the axis of the suction bell mouth 14. The lower end opening 24 of the axial center bell mouth 23 is located on the bottom wall 6 side from the suction port 15 of the suction bell mouth 14 so as to be located above the bottom wall 6 of the suction water tank 5 with a predetermined interval. The underwater vortex prevention rib 25 is a rectifying plate that can effectively eliminate the underwater vortex, and is provided so as to protrude radially outward with respect to the axial center bell mouth 23. The upper edge of the underwater vortex prevention rib 25 is formed in a shape along the inner surface of the suction bell mouth 14 and is connected to the suction bell mouth 14 by a bolt or the like.

  As shown in FIGS. 1 and 4, the vibration control device 26 is provided for the purpose of attenuating long-period ground motion that sways at a long period and preventing vibration of the casing 11 during operation. The vibration control device 26 includes a liquid flow path 27 disposed in the lower outer peripheral portion of the casing 11 located in the suction water tank 5 and a gas flow path 37 disposed in the upper outer peripheral portion of the casing 11. In the present embodiment, the liquid channel 27 and the gas channel 37 form an endless closed circuit through which liquid and gas can flow.

  The liquid flow path 27 contains liquid (water) in a flowable manner, and suppresses long-period ground motion applied to the casing 11. Further, by changing the weight of the lower portion of the casing 11, it also serves as a weight variable unit that adjusts the natural frequency of the vertical shaft pump 10 so as to deviate from the excitation frequency. The liquid flow path 27 includes liquid vertical pipes 28A to 28D extending in parallel along the axis of the casing 11, and a liquid horizontal pipe 32 connected to the lower ends of the liquid vertical pipes 28A to 28D. These liquid pipes 28A to 28D, 32 are made of resin pipes such as FRP. Among them, the liquid vertical pipe 28 </ b> A is provided with a liquid flow resistance portion 36 at a portion immersed in the stored water.

  As shown in FIG. 2 and FIG. 3A, the liquid vertical pipes 28 </ b> A to 28 </ b> D are arranged in the circumferential direction with an interval of 90 degrees on the outer peripheral portion of the casing 11. These liquid vertical pipes 28 </ b> A to 28 </ b> D are attached to the outer side in the radial direction with a predetermined interval between the casing 11 and the attachment member 29. The attachment position by the attachment member 29 is preferably a portion where the pumping pipe 12 is likely to vibrate, and is fixed to the connection flange portion 30 of the pumping pipe 12 in this embodiment. The upper ends of the vertical liquid pipes 28 </ b> A to 28 </ b> D are set higher than the highest water level of the wastewater stored in the suction water tank 5. As clearly shown in FIG. 1, connection portions 31 </ b> A to 31 </ b> D are provided at the upper ends of the liquid vertical pipes 28 </ b> A to 28 </ b> D to connect gas vertical pipes 38 </ b> A to 38 </ b> D described later in a liquid-tight and air-tight manner. The lower ends of the liquid vertical pipes 28 </ b> A to 28 </ b> D are set so as to be positioned on the outer peripheral portion of the suction bell mouth 14.

  The liquid vertical pipes 28 </ b> A and 28 </ b> B are arranged upstream of the main shaft 19 (suction bell mouth 14) with respect to the inflow direction of water into the suction water tank 5. The liquid vertical pipes 28 </ b> C and 28 </ b> D are positioned downstream of the main shaft 19 with respect to the inflow direction into the suction water tank 5. In addition, the inflow direction downstream side in the suction water tank 5 is blocked by a vertical wall (not shown). When the drainage collides with the vertical wall, a vortex is easily generated so as to be wound inward from both sides. When this vortex grows, a vortex (air suction vortex) that sucks air from the water surface to the suction port 15 is generated. Downstream liquid vertical pipes 28C and 28D are arranged in a region where the air suction vortex is likely to occur. Moreover, when newly constructing the pump structure 1 including the suction water tank 5, it is preferable to perform piping so that the liquid vertical pipes 28 </ b> A to 28 </ b> D are located in the east, west, south, and north.

  The liquid horizontal pipe 32 is an annular pipe disposed so as to be positioned on the lower end side of the casing 11. As clearly shown in FIG. 3B, the liquid horizontal pipe 32 of this embodiment is formed in an annular shape by connecting a pair of semi-annular pipes 33A and 33B. The lower ends of the liquid vertical pipes 28A to 28D are liquid-tightly joined to the liquid horizontal pipe 32, and the liquid vertical pipes 28A to 28D communicate with each other. The liquid horizontal pipe 32 is arranged so as to surround the outside of the reduced diameter portion of the suction bell mouth 14 with a space by a support portion 34 provided on the outer peripheral portion of the suction bell mouth 14. The support portions 34 are provided at four positions with an interval of 90 degrees, and also serve as a rectifying plate that prevents a swirling flow generated at the outer peripheral portion of the suction bell mouth 14.

  Between the liquid horizontal pipe 32 and the suction bell mouth 14, a sub-flow channel 35 is formed that extends radially outward from the upper side to the lower side. As shown in FIG. 2, the water flow (air suction vortex) from the water surface toward the suction port 15 is divided into a main flow X flowing outside the liquid horizontal pipe 32 and a sub flow Y flowing through the sub flow channel 35. Among them, the main flow X flows radially inward from the water surface toward the suction port 15 of the suction bell mouth 14, and the side flow Y flows radially outward along the outer peripheral surface of the suction bell mouth 14. Since the main flow X and the side flow Y disappear by colliding with the outer peripheral portion of the lower end of the suction bell mouth 14, the generation of the air suction vortex can be prevented.

  The liquid flow resistance portion 36 is provided on the lower end side of the liquid vertical pipe 28 </ b> A and suppresses the flow of water flowing in the liquid flow path 27. The liquid flow resistance portion 36 is composed of an orifice that has a smaller opening area in the middle portion than the opening area of the entrance and exit, and that can suppress the liquid volume that can be passed. In addition, the liquid flow resistance part 36 may use the valve which can adjust an aperture ratio by manual operation instead of an orifice. Further, an electromagnetic valve that is controlled to open and close by input of a signal may be used. Further, the liquid flow resistance portion 36 may be provided not only in the liquid vertical pipe 28A but also in the pair of liquid vertical pipes 28A and 28B, or may be provided in all the liquid vertical pipes 28A to 28D. Further, only one liquid horizontal pipe 32 may be provided.

  The gas flow path 37 accommodates gas (air) in a flowable manner therein, and, like the liquid flow path 27, suppresses long-period ground motion applied to the casing 11. The gas flow path 37 includes gas vertical pipes 38A to 38D extending in parallel along the axis of the casing 11, and gas horizontal pipes 39 connected to the upper ends of the gas vertical pipes 38A to 38D. These gas pipes 38A to 38D, 39 are made of resin pipes such as FRP. The gas horizontal pipe 39 is provided with an airflow resistance portion 40.

  As shown in FIGS. 1 and 4, the gas vertical pipes 38 </ b> A to 38 </ b> D are circumferentially spaced 90 degrees apart from the outer periphery of the casing 11 so as to be positioned along the axis of the liquid vertical pipes 28 </ b> A to 28 </ b> D. Is arranged. The lower ends of the gas vertical pipes 38A to 38D are connected to the connection portions 31A to 31D of the liquid vertical pipes 28A to 28D. The upper ends of the liquid vertical pipes 28 </ b> A to 28 </ b> D are disposed in the pump chamber 4 through the arrangement hole 3 of the installation floor 2.

  The gas horizontal pipe 39 is an annular pipe disposed so as to be positioned on the outer peripheral portion of the discharge bend 16 in the pump chamber 4. The liquid horizontal pipe 32 of the present embodiment is formed in an annular shape by connecting a pair of semicircular tubular pipes similarly to the liquid horizontal pipe 32. The upper ends of the gas vertical pipes 38A to 38D are airtightly joined to the gas horizontal pipe 39, and the gas vertical pipes 38A to 38D communicate with each other.

  The airflow resistance unit 40 is provided in the gas horizontal pipe 39 and suppresses the flow of air flowing in the gas flow path 37. The airflow resistance unit 40 is configured by a valve that can adjust an opening area of an intermediate portion with respect to an opening area of an entrance / exit by manual operation, and can suppress a gas volume that can pass therethrough. The airflow resistance unit 40 may use an electromagnetic valve or an orifice instead of a valve. The airflow resistance unit 40 may be provided in any one of the gas vertical pipes 38A to 38D, may be provided in the pair of gas vertical pipes 38A and 38B, or all the gas vertical pipes 38A. -38D may be provided.

  The vibration control device 26 of the present embodiment includes a water supply unit 41 for supplying a predetermined amount of liquid into the liquid channel 27, and an air supply unit 42 for adjusting the air pressure in the gas channel 37 to a predetermined pressure. Is provided. In addition, a discharge portion 43 is provided that enables drainage of the liquid in the liquid channel 27 and depressurization in the gas channel 37.

  The water supply unit 41 includes a pump disposed in the pump chamber 4, and this pump is connected to the gas horizontal pipe 39. The water supply unit 41 supplies water, which is a liquid having a specific gravity greater than that of air, from a water source (not shown) to the liquid channel 27 via the gas channel 37. The amount of water supply is set to an amount that allows the water in the liquid flow path 27 to have a natural frequency and suppress long-period ground motion. More specifically, water is supplied not only to the horizontal liquid pipe 32 but also to a height at which the liquid flow resistance portion 36 of the vertical liquid pipe 28A is submerged.

In the liquid flow path 27 of the present embodiment, liquid vertical pipes 28 </ b> A to 28 </ b> D communicate with each other via a liquid horizontal pipe 32. Among the liquid vertical pipes 28A to 28D, a pair of opposing liquid vertical pipes 28A, 28D or 28B, 28C form a liquid channel 27 having a U-shaped cross section that provides a dynamic vibration absorber effect. Then, the total length of the liquid column made of water from one of the liquid vertical pipes 28A and 28B to the other liquid vertical pipe 28D and 28C is set to a length capable of suppressing the rolling due to the assumed earthquake. A dynamic vibration absorber effect is obtained by the oscillation of the liquid column, and the vibration of the casing 11 is suppressed.

  The air supply unit 42 includes a compressor disposed in the pump chamber 4, and this compressor is connected to the gas horizontal pipe 39. The air supply unit 42 adjusts (increases) the air pressure in the liquid flow path 27 by supplying compressed air into the liquid horizontal pipe 32 and the liquid vertical pipes 28 </ b> A to 28 </ b> D. When the gas flow path 37 is made higher than the atmospheric pressure by the air supply unit 42, the flow of water in the liquid flow path 27 becomes faster and the natural frequency can be increased. When the gas flow path 37 is made lower than the atmospheric pressure by the air supply unit 42, the flow of water in the liquid flow path 27 becomes slow, and the natural frequency can be lowered. Therefore, by adjusting the pressure in the gas flow path 37 by the air supply unit 42, the natural frequency due to water in the liquid flow path 27 can be adjusted.

  The discharge part 43 includes a drain valve disposed in the pump chamber 4 and is connected to the gas horizontal pipe 39. The discharge part 43 can release (exhaust) the pressure in the gas flow path 37 by opening. Further, by operating the air supply unit 42 in the open state, the water in the liquid flow path 27 can be pushed up to the gas flow path 37 by air pressure and drained from the discharge unit 43. That is, the discharge unit 43, the water supply unit 41, and the air supply unit 42 serve as a water amount adjustment unit that adjusts the amount of water in the liquid channel 27. Further, the discharge unit 43 and the air supply unit 42 serve as a pressure adjustment unit that adjusts the air pressure in the gas flow path 37. In addition, in order to improve drainage, you may connect the discharge part 43 to the horizontal piping 32 for liquids.

  The vertical shaft pump 10 is designed in a balanced manner based on the rigidity of the installation floor 2 of the installation place. When the vertical shaft pump 10 is installed on the installation floor 2, the discharge unit 43 is opened, and water is supplied from the water supply unit 41 into the liquid channel 27 via the gas channel 37. As a result, the liquid horizontal pipe 32 is filled with water, and water is also supplied to the liquid vertical pipes 28A to 28D so that the total length of the liquid column becomes the set length. As a result, the liquid flow resistance portion 36 provided in the liquid flow path 27 is immersed.

  Next, the vertical shaft pump 10 is tested and vibrations applied to the installation floor 2 are detected by a known vibration sensor or the like. If the detected value does not fall within the set allowable range, it is determined that vibration exceeding the allowable value has occurred, and the vibration control device 26 is adjusted so as to suppress the vibration.

  Here, the principle of vibration suppression by the vibration control device 26 will be described.

  First, the conventional vertical shaft pump 10 without the vibration control device 26 is a single-degree-of-freedom vibration system structure having a single natural frequency component that resonates with the rotational speed of the drive unit 22. The vertical pump 10 of a vibration system with one degree of freedom vibrates greatly due to resonance when the excitation frequency Ω matches the natural frequency ω due to the balance between the rigidity of the installation floor 2 and the casing 11. Therefore, if the natural frequency ω of the vertical pump 10 is adjusted so as to deviate from the excitation frequency Ω, vibration due to resonance can be suppressed.

  In the vertical shaft pump 10 of the present embodiment provided with the vibration control device 26, since the liquid flow path 27 is connected to the casing 11 by the support portion 34, the structure of a two-degree-of-freedom vibration system having two different natural frequency components. Make up the body. That is, a first natural frequency ω1 on the casing 11 side (main system) and a second natural frequency ω2 on the liquid flow path 27 side (secondary system) are generated. An excitation frequency Ω is set between these two natural frequencies ω1 and ω2 (ω1 <Ω <ω2). As a result, the vibrations of the main system and the sub system are out of phase with the excitation force on the low order mode side, and the main system is in phase with the excitation force and the sub system is out of phase on the high order mode side. When each vibration mode is added, the vibration of the main system cancels out the low-order vibration mode and the high-order vibration mode.

  The above relationship relates to the mass ratio μ between the casing 11 and the liquid flow path 27. Therefore, by supplying water to the liquid channel 27 as a subordinate system and adjusting the mass (= weight), the waveform positions of the natural frequencies ω1 and ω2 with respect to the excitation frequency Ω can be moved (adjusted). . Specifically, the natural frequency can be lowered by increasing the amount of water supply and increasing the mass. Conversely, the natural frequency can be increased by reducing the amount of water supplied and reducing the mass. By matching the lower limit peak value between the two natural frequencies ω1 and ω2 with the excitation frequency Ω, the vibration of the vertical pump 10 can be suppressed or substantially prevented by the dynamic vibration absorber effect.

  In order to suppress the vibration of the vertical pump 10, the natural frequency of the vertical pump 10 is adjusted. The adjustment of the natural frequency includes a method of adjusting the amount of water in the liquid channel 27 by the water supply unit 41 and a method of adjusting the pressure in the gas channel 37 by the air supply unit 42. Specifically, when the natural frequency is increased, the amount of liquid in the liquid channel 27 is decreased or the air pressure in the gas channel 37 is increased. When lowering the natural frequency, the amount of liquid in the liquid channel 27 is increased or the air pressure in the gas channel 37 is decreased.

  However, in the present embodiment, the total length of the liquid column in the liquid flow path 27 is set so that rolls caused by an assumed earthquake can be suppressed. Therefore, the natural frequency is adjusted by adjusting the pressure in the gas flow path 37 by the air supply unit 42. That is, after water is supplied into the vertical pipes 28A to 28D for liquid by the water supply part 41 to a predetermined height where the liquid flow resistance part 36 is immersed, the pressure in the gas flow path 37 is changed by the air supply part 42 to adjust the natural frequency. To do.

  In this way, the drainage operation is executed according to a program preset by a control device (not shown) in a state where the vibration of the vertical shaft pump 10 is suppressed by the vibration control device 26.

  During the drainage operation, water is supplied to the liquid pipes 28A to 28D and 32, and the natural frequencies ω1 and ω2 of the casing 11 are adjusted to deviate from the excitation frequency Ω, so that vibration can be suppressed. Further, since the vertical shaft pump 10 is a two-degree-of-freedom vibration system structure, vibration can be suppressed or substantially prevented more easily and reliably than a one-degree-of-freedom vibration system structure. As a result, damage to the installation floor 2 on which the vertical shaft pump 10 is installed can be reliably prevented. Moreover, since the lower part of the liquid vertical pipes 28A to 28D and the liquid horizontal pipe 32 are in a submerged state, resistance (viscous force) and additional mass due to water in the suction water tank 5 are generated and vibration is further reduced. it can.

  Further, when the water in the suction water tank 5 is drained to the vicinity of the impeller 21, an air suction vortex tends to be generated in a region downstream of the suction bell mouth 14 in the inflow direction into the suction water tank 5. However, the vertical pump 10 according to the present embodiment includes the vertical pipes 28C and 28D for liquid that prevent the generation of the air suction vortex in the region, and therefore the generation of the air suction vortex on the water surface is effective. Can be suppressed. Moreover, since the water flow from the water surface toward the suction port 15 is divided into the main flow X and the subflow Y as shown in FIG. 2 and disappears by colliding with each other, the generation of the air suction vortex can be reliably prevented.

  Moreover, since the horizontal pipe 32 for liquid makes the annular | circular shape surrounding the casing 11, it can add weight to the lower part of the casing 11 uniformly by supply of water. Therefore, vibration can be reliably suppressed without losing balance. Further, since the liquid pipes 28A to 28D, 32 and the gas pipes 38A to 38D, 39 are made of resin pipes, the workability can be greatly improved.

Moreover, the vibration damping device 26 of the present embodiment can suppress long-period ground motion due to earthquakes as well as vibration suppression during normal operation. Specifically, when the vertical shaft pump 10 receives an earthquake load (inertial force generated when it is shaken by the earthquake) due to an earthquake, the liquid column having a U-shaped cross section extending over each of the liquid vertical pipes 28A to 28D swings , It acts as a liquid column type dynamic vibration absorber. And since the full length of the liquid column in the liquid flow path 27 is set to the length which can suppress the rolling by the assumed earthquake, the vibration added to the pump structure 1 by an earthquake can be reduced.

  In addition, since the liquid flow path 27 and the gas flow path 37 of the present embodiment are provided with the resistance portions 36 and 40 that can suppress the flow, the flow resistance and air flow resistance of water in the liquid flow resistance portion 36. The seismic vibration energy is absorbed by the flow resistance of the gas in the portion 40. That is, since the water flowing through the liquid flow path 27 is suppressed by the liquid flow resistance portion 36, the seismic vibration energy is absorbed, and the air flowing through the gas flow path 37 is suppressed by the air flow resistance portion 40 by this water flow. The seismic vibration energy is absorbed. Therefore, vibration with respect to the pump structure 1 can be further reduced. Further, in addition to the additional mass due to water, the liquid stored in the liquid flow path 27 can counteract the excitation force caused by the earthquake due to the increase in pump weight. Therefore, the effect of improving the earthquake resistance against the earthquake is obtained, and the pump reliability can be enhanced.

(Modification of the first embodiment)
In the first embodiment, the airflow resistance portion 40 is provided in the gas flow path 37, but the airflow resistance portion 40 may not be provided. Moreover, although the air supply part 42 and the discharge part 43 for adjusting the pressure of the gas flow path 37 are provided, the air supply part 42 and the discharge part 43 may be omitted. Further, the vibration control device 26 may be assembled in a state where a preset amount of water is accommodated in the liquid flow path 27 without providing the water supply unit 41.

  Moreover, as shown in FIG. 5, it is good also as a structure which does not provide gas flow path 37 itself. In this case, the upper ends of the liquid vertical pipes 28 </ b> A to 28 </ b> D set higher than the highest water level of the wastewater stored in the suction water tank 5 are preferably sealed in a liquid-tight manner, but may be opened. When the upper ends of the liquid vertical pipes 28 </ b> A to 28 </ b> D are opened, the amount of liquid (= weight) in the liquid flow path 27 increases when drainage enters, so the set natural frequency changes. However, in this embodiment, since the upper ends of the vertical liquid pipes 28A to 28D are set higher than the maximum water level, such a problem does not occur.

(Second Embodiment)
6 and 7 show the vibration control device 26 of the vertical shaft pump 10 of the second embodiment. The second embodiment is different from the first embodiment in that the liquid flow path 27 is formed by only the liquid vertical pipes 28A to 28D extending along the casing 11 without providing the liquid horizontal pipe 32.

  The straight pipe-shaped vertical liquid pipes 28 </ b> A to 28 </ b> D are arranged by the attachment member 29 at an interval of 90 degrees on the outer peripheral portion of the casing 11 as in the first embodiment. The upper ends of the vertical liquid pipes 28 </ b> A to 28 </ b> D are set higher than the highest water level of the wastewater stored in the suction water tank 5. The lower ends of the liquid vertical pipes 28 </ b> A to 28 </ b> D of the second embodiment are set at a position lower than the lowest water level of the liquid stored in the suction water tank 5 and are opened in the suction water tank 5. Specifically, the lower ends of the vertical liquid pipes 28 </ b> A to 28 </ b> D are set to extend toward the bottom wall 6 beyond the suction port 15 at the lower end of the suction bell mouth 14. Among them, the liquid vertical pipe 28A is provided with a liquid flow resistance portion 36 that suppresses the flow of flowing water.

  As shown in FIG. 7, the vibration damping device 26 of the second embodiment is connected to the connection portions 31 </ b> A to 31 </ b> D at the upper ends of the straight tubular liquid vertical pipes 28 </ b> A to 28 </ b> D constituting the liquid flow path 27. Similarly, a gas flow path 37 is connected. Further, the gas horizontal pipe 39 of the gas flow path 37 is provided with an airflow resistance unit 40, a water supply unit 41, and a discharge unit 43 in the first embodiment. However, the air supply unit 42 is not provided in the second embodiment.

  The vertical shaft pump 10 according to the second embodiment is installed on the installation floor 2 as in the first embodiment, and vibration is suppressed by the vibration control device 26. When adjusting the natural frequency of the vertical shaft pump 10 for vibration suppression, the gas flow path 37 is set by the water supply unit 41 with the lower ends of the vertical liquid pipes 28 </ b> A to 28 </ b> D immersed in the waste water in the suction water tank 5. Then, water is supplied to the liquid flow path 27. At this time, the discharge unit 43 is in a closed state in which communication with the outside is blocked. Thereby, water can be accommodated to the set height of each vertical pipe 28A-28D for liquids.

And if drainage operation is performed, while being able to reduce the vibration at the time of operation | movement similarly to 1st Embodiment, generation | occurrence | production of an air suction vortex can be prevented. Further, the liquid vertical pipes 28 </ b> A to 28 </ b> D communicate with each other through the waste water stored in the suction water tank 5. Therefore, the liquid column having a U-shaped cross section that extends to each of the liquid vertical pipes 28A to 28D through the suction water tank 5 is swung , thereby functioning as a liquid column tube type dynamic vibration absorber. Therefore, since long-period ground motion due to an earthquake can be suppressed, vibration applied to the pump structure 1 can be reliably reduced. Further, since the vibration damping device 26 does not have the liquid horizontal pipe 32 connected to the liquid vertical pipes 28A to 28D, the configuration can be simplified and the assembly workability can be improved.

(Modification of the second embodiment)
In the second embodiment, the airflow resistance portion 40 is provided in the gas flow path 37, but the airflow resistance portion 40 may not be provided. Moreover, although the water supply part 41 and the discharge part 43 for adjusting the water quantity in the liquid flow path 27 were provided, it is good also as a structure which does not provide these water supply parts 41 and the discharge part 43. Moreover, as shown in FIG. 8, it is good also as a structure which does not provide gas flow path 37 itself. In this case, the upper ends of the liquid vertical pipes 28A to 28D are preferably hermetically sealed, but may be opened.

(Third embodiment)
9 and 10 show the vibration control device 26 of the vertical shaft pump 10 of the third embodiment. The third embodiment is different from the first and second embodiments in that first and second vibration control units 26A and 26B that are partitioned in a non-communication state are provided. The first liquid flow path 27A of the first vibration control unit 26A has the same configuration as that of the first embodiment shown in FIG. 4, and the second liquid flow path 27B of the second vibration control unit 26B is shown in FIG. It is the same structure as the modification of 2nd Embodiment.

  In the first liquid flow path 27A, a gas flow path 37 is provided in the same manner as in the first embodiment, and an endless closed circuit through which liquid and gas can flow is formed. The gas flow path 37 is provided with an airflow resistance unit 40, a water supply unit 41, an air supply unit 42, and a discharge unit 43.

  The second liquid channel 27B is provided so as to be positioned on the outer peripheral portion of the first liquid channel 27A. The gas flow path 37 is not provided in the second liquid flow path 27B composed of the vertical liquid pipes 28A2 to 28D2. Moreover, as for the vertical piping 28A2-28D2, the lower end is set to a position lower than the lowest water level, and the upper end is set higher than the highest water level. The liquid vertical pipes 28 </ b> A <b> 2 to 28 </ b> D <b> 2 communicate with each other via the suction water tank 5.

  In the third embodiment thus configured, it is possible to obtain the same operations and effects as in the first and second embodiments. The first and second liquid flow paths 27A and 27B have different distances from the axial line of the casing 11 to the liquid vertical pipes 28A1 to 28D1 and 28A2 to 28D2. Since the first and second liquid channels 27A and 27B are independent and different channels, they can be set so that their natural frequencies are different from each other. Therefore, it is possible to suppress a wide range of long-period ground motion.

(Modification of the third embodiment)
In the third embodiment, the gas flow path 37 is not provided in the second liquid flow path 27B. However, the gas flow path 37 may be provided as in the second embodiment. Further, the gas flow path 37 may be provided in the second liquid flow path 27B without providing the gas flow path 37 in the first liquid flow path 27A. Moreover, it is good also as a structure which does not provide the gas flow path 37 in both the 1st and 2nd liquid flow paths 27A and 27B.

  In the third embodiment, the first liquid channel 27A similar to the first embodiment and the second liquid channel 27B of the second embodiment are combined, but as shown in FIG. The first liquid flow path 27A (the liquid vertical pipes 28A1 to 28D1 and the liquid horizontal pipe 32A) similar to the first embodiment and the first liquid flow path 27A are different from each other in the distance from the axis of the casing 11. You may comprise combining the 2nd liquid flow path 27B (liquid vertical piping 28A2-28D2 and liquid horizontal piping 32B) substantially the same as 1st Embodiment. Further, as shown in the drawing, the gas flow path 37A, 37B may be configured not to be provided with the airflow resistance portion 40. Moreover, it is good also as a structure which does not provide the water supply part 41, the air supply part 42, and the discharge part 43. FIG.

  In addition, the damping device 26 of the pump 10 of the present invention is not limited to the configuration of the above embodiment, and various modifications can be made.

  For example, although the vertical pipes 28A to 28D and 38A to 38D are communicated with the annular horizontal pipes 32 and 39, the horizontal pipes 32 and 39 are opposite to the liquid vertical pipes 28A and 28D and the gas vertical pipe 38A. , 38D may be connected so as to communicate with each other, and the other opposing liquid vertical pipes 28B, 28C and gas vertical pipes 38B, 38C may be connected. If it does in this way, two or more closed circuits which make a U shape can be formed easily. In the third embodiment, two sets of vibration control units are provided, but three or more sets of vibration control units may be provided.

  In the first embodiment, the liquid flow path 27 is composed of the liquid vertical pipes 28 </ b> A to 28 </ b> D and the liquid horizontal pipe 32. In the second embodiment, a plurality of liquid vertical pipes 28 </ b> A to 28 </ b> A to communicate with each other via the suction water tank 5. The liquid flow path 27 is composed of 28D, and the gas flow path 37 is connected to each of the liquid vertical pipes 28A to 28D. For example, a connecting portion is provided in the liquid horizontal pipe 32 of the first embodiment to provide a gas vertical pipe 38A. ~ 38D may be directly connected.

  And in the said embodiment, although the damping device 26 of this invention was applied to the vertical shaft pump 10, it is applicable also to the horizontal shaft pump which has arrange | positioned the main axis | shaft 19 with respect to the casing 11, and the same effect | action. And can get the effect. That is, any pump can be used as long as the casing 11 is arranged vertically downward from the arrangement hole 3 of the installation floor 2.

DESCRIPTION OF SYMBOLS 1 ... Pump structure 2 ... Installation floor 3 ... Arrangement hole 4 ... Pump chamber 5 ... Suction water tank 10 ... Vertical shaft pump 11 ... Casing 15 ... Suction port 19 ... Main shaft 21 ... Impeller 22 ... Drive machine (drive means)
23 ... Axial bell mouth 26 ... Vibration control device 27 ... Liquid channel 28A-28D ... Vertical pipe for liquid (vertical pipe)
31A-31D ... Connection part 32 ... Horizontal piping for liquid (horizontal piping)
36 ... Liquid flow resistance part 37 ... Gas flow path 38A-38D ... Vertical pipe for gas 39 ... Horizontal pipe for gas 40 ... Airflow resistance part

Claims (8)

A vibration control device for a pump comprising a casing extending vertically in the suction water tank through an arrangement hole in the installation floor,
Together are provided et the outer periphery of the casing positioned in the suction water tank, two or more connecting portions are formed, a liquid flow path for fluidly containing a liquid therein,
A liquid flow resistance portion that is provided in the liquid flow path and suppresses the flow of liquid in the liquid flow path ;
A pump vibration control device comprising: a gas flow path having a lower end connected to each connection portion of the liquid flow path and having an upper end side communicated with each other . A vibration control device for a pump comprising a casing extending vertically in the suction water tank through an arrangement hole in the installation floor,
  A liquid flow path that is provided in an outer peripheral portion of the casing located in the suction water tank and accommodates a liquid in a flowable manner therein;
  A liquid flow resistance portion that is provided in the liquid flow path and suppresses the flow of the liquid in the liquid flow path;
  With
  The vibration control device for a pump according to claim 1, wherein the liquid flow path includes first and second liquid flow paths partitioned in a non-communication state. At least one of the first and second liquid channels has two or more connecting portions,
With the lower end connected to the front Symbol respective connecting portions, vibration control device of the pump according to claim 2, characterized in that the upper end side further comprises a communicated with the gas passage with each other. The vibration control device for a pump according to claim 1 or 3 , wherein an airflow resistance portion for suppressing gas flow is provided in the gas flow path. The said liquid flow path has two or more vertical piping extended along the axis line of the said casing, and the horizontal piping which connects the lower end side of each said vertical piping, The any one of Claim 1 to 4 characterized by the above-mentioned. The vibration control device for a pump according to the item . The said liquid flow path has two or more vertical piping extended along the axis line of the said casing, The lower end of each said vertical piping is open | released in the said suction water tank, The Claim 1 to 4 characterized by the above-mentioned . A vibration control device for a pump according to any one of the preceding claims. The pump damping device according to claim 6 , wherein a lower end of the vertical pipe is set lower than a minimum water level of the liquid stored in the suction water tank. The upper end of the vertical pipe, vibration control device of the pump according to any one of claims 5 to 7, characterized in that it is set higher than the maximum level of the liquid reserved in the suction water tank .

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