JP2011058409A - Vortex type centrifugal pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vortex type centrifugal pump capable of effectively discharging a gaseous lump formed in a center region of a vortex chamber without provisional stop of a pump or special exhaust means. <P>SOLUTION: A vortex type centrifugal pump has an impeller rotating around an axis and a pump casing covering the impeller, and includes a vortex chamber forming vortex flow by rotation of the impeller in an inner space formed inside the pump casing, wherein a stirring member for agitating a vortex flow formed in the vortex chamber is arranged in an outer peripheral region of the vortex chamber. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vortex-type centrifugal pump having a wide space between a pump casing and an impeller and suitable for conveying sewage and filth, and more particularly, impeller even for sewage and filth mixed with gas. The present invention relates to a vortex-type centrifugal pump that can continuously discharge the sewage and filth without forming a gas reservoir around the center of the slab.

  The centrifugal pump discharges the liquid by applying a radial pressure to the liquid by a centrifugal force generated by the rotation of the impeller. As one of the centrifugal pumps, it is suitable for use in purification systems that purify sewage and filth such as human waste, so that even large foreign substances contained in sewage and filth can pass through, between the pump casing and the impeller. There is a vortex type centrifugal pump having a large space (see, for example, Patent Document 1).

  The vortex type centrifugal pump can perform its function when transporting sewage and filth containing large foreign matter. However, if gas is mixed in the sewage or filth, the sewage or filth mixed with the gas is The gas portion having a lighter specific gravity than the liquid portion stays in the central region of the spiral chamber. Such a gas retention phenomenon causes problems such as a decrease in pump discharge capacity and inability to pump water.

  For example, a sewage / dirt purification treatment system includes an aeration tank that sends air (oxygen) into the sewage / sewage to activate the activity of microorganisms. Therefore, a large amount of air is mixed in the sewage and filth passed through the aeration tank. When sewage / dirt mixed with air is conveyed by a vortex-type centrifugal pump in the aeration tank, the mixed air separates from the liquid part of the sewage / filth and collects and stays in the central area of the spiral chamber, resulting in a swirl. A gas mass is formed in the central region of the chamber. Therefore, in the vortex type centrifugal pump that conveys sewage and filth passed through the aeration tank, problems such as reduction in pump discharge capacity and inability to pump water occur.

  In order to avoid such problems in the vortex type centrifugal pump, it is possible to temporarily stop the pump or to install an exhaust means for forcibly exhausting the gas staying in the central region of the spiral chamber. Has been done.

JP 2003-239895 A

  Since the vortex type centrifugal pump is incorporated as one of the important equipment for operating the sewage and sewage purification system, the temporary suspension of the pump has a great influence on the entire sewage treatment system. End up.

  As exhaust means for forcibly exhausting a gas mass formed in the central region of the pump's spiral chamber, exhaust means such as a gas vent hole and a gas vent valve are installed. However, the installation of exhaust means such as a gas vent hole or a gas vent valve has problems such as water leakage from the gas vent hole, blockage of the gas vent hole or gas vent valve, and cost increase due to the exhaust means installation.

  Therefore, the technical problem to be solved by the present invention is to effectively exhaust the gas mass formed in the central region of the spiral chamber without temporarily stopping the pump or providing a special exhaust means. It is to provide a vortex type centrifugal pump that can be used.

  In order to solve the above technical problem, according to the present invention, the following vortex type centrifugal pump is provided.

That is, the vortex centrifugal pump according to claim 1 of the present invention is
A spiral chamber having an impeller that rotates about an axis and a pump casing that covers the impeller, and an internal space formed inside the pump casing forms a spiral flow by the rotation of the impeller In a vortex centrifugal pump comprising
A stirring member for stirring the spiral flow formed in the spiral chamber is disposed in an outer peripheral region of the spiral chamber.

  The vortex centrifugal pump according to claim 2 of the present invention is characterized in that the agitating member extends from a discharge port provided at a terminal portion of the spiral chamber substantially toward the axial center.

  In the vortex centrifugal pump according to claim 3 of the present invention, the stirring member has a substantially semi-cylindrical shape fitted to the internal shape of the discharge port, and the opening of the substantially semi-cylindrical stirring member has a spiral flow. It is arrange | positioned so that it may face.

  The vortex centrifugal pump according to claim 4 of the present invention is characterized in that one end of the stirring member has a flange, and the flange is attached to the flange portion of the discharge port.

  The vortex centrifugal pump according to claim 5 of the present invention is characterized in that the agitating member extends from the inner wall surface of the pump casing forming the spiral chamber substantially toward the axial center.

  In the vortex centrifugal pump according to claim 6 of the present invention, the stirring member extends to a central region of the spiral chamber.

  The present invention according to claim 1 is characterized in that the spiral flow formed in the spiral chamber is stirred by the stirring member disposed in the outer peripheral region of the spiral chamber. When gas is mixed into sewage / sewage, the swirl flow of sewage / soil with gas is separated into a gas part and a liquid part by centrifugal force. A gas portion having a specific gravity lower than that of the liquid portion collects and stays in the central region of the spiral chamber, thereby forming a gas mass and forming a swirl flow in which the liquid portion swirls in the outer peripheral region of the spiral chamber. The swirl flow is stirred by colliding with the stirring member disposed in the outer peripheral area of the swirl chamber.

  That is, a part of the collision flow (axial flow) generated by the swirling flow colliding with the stirring member is directed to the gas mass formed in the central region of the spiral chamber, and the gas mass is crushed into minute bubbles. . The liquid component containing minute bubbles again becomes a swirl flow swirling in the outer peripheral region of the spiral chamber. A part of the collision flow (anti-axial flow) generated when the swirling flow collides with the stirring member again is directed to the discharge port, and the anti-axial flow is discharged from the discharge port. By repeating such a series of operations continuously in the spiral chamber, the volume of the gas mass existing in the central region of the spiral chamber gradually decreases, and finally the gas mass is completely discharged. Therefore, the present invention according to claim 1 can effectively discharge the gas mass retained in the central region of the spiral chamber without temporarily stopping the operation of the pump or without providing a special exhaust means. There is an effect.

  The stirring member that is disposed in the outer peripheral region of the swirl chamber and stirs the swirl flow can be implemented in various modes, but extends substantially from the discharge port provided at the end of the swirl chamber toward the axial center. Implemented in an embodiment. Therefore, the present invention according to claim 2 has an effect that the installation of the stirring member is easy and the installation cost of the stirring member is low.

  The internal shape of the discharge port is often cylindrical from the viewpoint of workability. Therefore, the present invention according to claim 3 has an effect of suppressing the generation of rattling noise caused by poor attachment in which the stirring member is not closely fixed to the discharge port.

  There are various modes for installing the agitating member, but the agitating member is welded and fixed to the inner wall surface of the discharge port, or the agitating member is fitted and fixed in a slit-like opening hole provided around the discharge port. However, in these installation methods, the mounting property and the sealing property are not necessarily good. Therefore, the present invention according to claim 4 is advantageous in that the installation of the stirring member is easy and the installation cost of the stirring member is low.

  The stirring member that is disposed in the outer peripheral region of the swirl chamber and stirs the swirl flow can be implemented in various modes. The stirrer is generally directed from the inner wall surface of the pump casing that forms the swirl chamber toward the axial center. Implemented in an extended manner. Therefore, the present invention according to claim 5 is advantageous in that the installation of the stirring member is easy and the installation cost of the stirring member is low.

  The present invention according to claim 5 has an effect of making the stirring action by the stirring member provided close to the gas mass more effective.

It is a figure explaining an example of the purification processing system which uses the vortex type | mold centrifugal pump of this invention, and carries out the purification process of sewage and filth, such as human waste. 1 is an overall view of a vortex centrifugal pump according to an embodiment of the present invention. It is principal part sectional drawing of the vortex type centrifugal pump which concerns on 1st embodiment of this invention. It is the typical explanatory view which looked at the vortex type centrifugal pump shown in Drawing 3 from the direction of the bottom (suction port). It is the typical explanatory view which looked at the vortex type centrifugal pump shown in FIG. 3 from the left side. It is a schematic diagram explaining the flow in a spiral chamber corresponding to FIG. It is a schematic diagram explaining the flow in a spiral chamber corresponding to FIG. It is a schematic diagram explaining the flow in a spiral chamber corresponding to FIG. It is principal part sectional drawing of the vortex type centrifugal pump which concerns on 2nd embodiment of this invention. It is the typical explanatory view which looked at the vortex type centrifugal pump shown in Drawing 9 from the direction of the bottom (suction port). It is principal part sectional drawing of the vortex type centrifugal pump which concerns on 3rd embodiment of this invention. It is typical explanatory drawing which looked at the vortex type centrifugal pump shown in FIG. 11 from the bottom face (suction port).

  Hereinafter, a first embodiment of a vortex centrifugal pump 1 according to the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a diagram for explaining an example of a purification processing system for purifying sewage and filth such as human waste, in which the vortex centrifugal pump 1 of the present invention is used. The usage pattern of the vortex centrifugal pump 1 of the present invention is not limited to the purification treatment system shown in FIG.

  The sewage / dirt purification treatment system illustrated in FIG. 1 is mainly composed of a sewage / sewage acceptance / pretreatment process and a pre-treated sewage / sewage primary / secondary treatment process.

  In the sewage and waste receiving / pretreatment process including human waste and septic tank sludge, the following is performed. That is, sewage and filth such as human waste collected by a transport vehicle are stored in a receiving tank (sedimentation basin) of the processing center and then crushed into small pieces so as to be easily processed by the crusher C. It is sent to a drum screen that removes “sediment”, which is an impurity. Impurities removed from sewage and filth are drained through a dehydrating device that applies pressure called a screw press, and finally incinerated in a garbage incineration facility. Then, sewage such as human waste is stored in a storage tank and then sent to a sewage treatment plant by a pump P ′.

  In the primary and secondary treatment processes, organic components (BOD) and nitrogen components such as ammonia are decomposed and removed in a biological treatment tank as follows. That is, sewage such as human waste from the storage tank is denitrified by the action of denitrifying bacteria in the denitrification tank, and nitrate nitrogen is decomposed into nitrogen gas and water. Further, a large amount of air (oxygen) is blown into the nitrification tank (aeration tank) by the blower B to promote nitrification, change ammoniacal nitrogen to nitrate nitrogen, and oxidize organic matter to water and carbon dioxide. Further, in order to increase efficiency, a part is circulated to the denitrification tank, but the vortex centrifugal pump P of the present invention is used as a lifting means for lifting the sewage aerated in the nitrification tank to the denitrification tank.

  In the denitrification tank in the secondary treatment step, nitrogen is removed under anaerobic conditions (there is no fresh air). In the nitrification tank (aeration tank) in the secondary treatment process, the carbon dioxide gas and nitrogen gas generated by the decomposition are degassed to enhance the sedimentation and concentration of sludge. The vortex type centrifugal pump P of the present invention is used as a lifting means for lifting the sewage aerated in the secondary treatment step to the settling tank. In the sedimentation tank, it is separated into supernatant water and sedimented sludge, and the supernatant water is made into colorless and odorless clean water in the advanced treatment process (coagulation sedimentation and ozone treatment) and then discharged into the public sewer, while the sedimented sludge is dehydrated. Incinerated after treatment.

  Next, the vortex centrifugal pump 1 according to the first embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 2 shows an overall view of the vortex centrifugal pump 1 according to the present invention. The vortex centrifugal pump 1 includes a motor 2 as driving means, an impeller 10 that is rotationally driven by a rotary shaft 6, a pump casing 20 that covers the impeller 10, and a support 18 that supports the pump. . The motor shaft 4 of the motor 2 is connected to the rotating shaft 6. The impeller 10 attached to the tip of the rotating shaft 6 rotates about the axis O as the motor shaft 4 rotates. Further, the vortex type centrifugal pump 1 includes a shaft seal mechanism by a mechanical seal 8 so that the pumped liquid does not leak to the motor 2 side.

  The impeller 10 has a plurality of (for example, 3 to 6) blades 12 arranged at a predetermined interval. A semi-open type or full-open type impeller 10 can be suitably used.

  The pump casing 20 has a suction port 22 provided on the front side of the impeller 10 and a discharge port 24 provided on the outer peripheral side of the impeller 10. And between the pump casing 20 and the lower edge of the impeller 10, a spiral chamber 30 having a wide space (gap) through which even a large foreign object can pass is formed. The spiral chamber 30 has a central region 32 located on the front side of the impeller 10 (that is, immediately below the impeller 10), and an outer peripheral region (volute portion) 34 existing on the outer periphery of the central region 32.

  A suction passage 23 that is curved at an angle of approximately 90 degrees communicates with the suction port 22 that opens in the direction of the axis O. A suction side flange 28 is formed at the end of the suction passage 23. A discharge flange 26 is formed at the end of the discharge port 24. The connection member 50 connected to the discharge side flange 26 has a flange at each end.

  The first embodiment is characterized in that the stirring member 40 is disposed in the discharge port 24 provided at the terminal portion of the outer peripheral region 34 of the spiral chamber 30. The stirring member 40 is made of a material having rigidity and corrosion resistance (for example, a stainless material such as SUS304 or SUS316), and has a substantially semi-cylindrical shape like a rain gutter. The stirring member 40 is configured to fit the internal shape (for example, a substantially cylindrical shape) of the discharge port 24. The stirring member 40 has a thickness that resists the pressure of the swirling flow 60A, and is 2 to 3 mm if the thickness of the stirring member 40 is exemplified.

  The stirring member 40 is disposed so that the opening 42 faces the swirl flow 60 </ b> A of the spiral flow 60. One end of the stirring member 40 has a flange 44, and the flange 44 of the stirring member 40 is fastened together between the discharge side flange 26 of the pump casing 20 and the flange of the connection member 50. Since the stirring member 40 having the flange 44 can be easily installed in the discharge port 24, the installation cost of the stirring member 40 is reduced. As shown in FIGS. 3 and 4, the other end of the agitating member 40 extends substantially toward the axial center O (that is, generally extends in the radial direction), and is an outer peripheral region 34 that is slightly in front of the impeller 10. It is terminated. The stirring member 40 having the opening 42 may have a U-shaped, V-shaped, or L-shaped cross section instead of the substantially semi-cylindrical cross section as shown in FIG. It is preferable that each end portion of the stirring member 40 is configured to abut on the internal shape of the discharge port 24. Further, the stirring member 40 may be fixed to the inner wall surface of the discharge port 24 by welding instead of fixing with the flange 44.

  With reference to FIGS. 6 to 8, the stirring action of the spiral flow 60 by the arrangement of the stirring member 40 according to the present invention will be described.

  Generally, when a liquid mixed with gas is lifted by a centrifugal pump, the liquid mixed with gas is separated into a gas part and a liquid part by centrifugal force, and a gas part having a specific gravity lighter than the liquid part is a spiral chamber 30. The gas mass 64 centering on the axis O is formed. Such a gas retention phenomenon causes problems such as a decrease in pump discharge capacity and inability to pump water.

  On the other hand, when the stirring member 40 extending from the discharge port 24 to the outer peripheral region 34 is disposed as in the present invention, the spiral flow 60 is stirred by the stirring member 40. That is, a part of the collision flow 60 </ b> B (axial flow 60 </ b> C) generated by the swirling flow 60 </ b> A swirling in the outer peripheral region 34 of the spiral chamber 30 collides with the stirring member 40 exists in the central region 32 of the spiral chamber 30. The gas mass 64 is crushed into a large number of minute bubbles 62 toward the gas mass 64 formed around the axis O. The liquid component including a large number of minute bubbles 62 again becomes a swirl flow 60A that swirls around the outer peripheral region 34 of the spiral chamber 30, but the swirl flow 60A including a large number of minute bubbles 62 collides with the stirring member 40 again. A part of the collision flow 60 </ b> B (anti-axial flow 60 </ b> D) generated by the above is directed toward the discharge port 24 and discharged through the discharge port 24.

  By repeating such a series of operations continuously in the spiral chamber 30, the volume of the gas mass 64 existing in the central region 32 of the spiral chamber 30 gradually decreases, and finally the gas mass 64 is completely discharged. As a result, the gas mass 64 disappears. Therefore, the vortex-type centrifugal pump 1 according to the first embodiment is also capable of pumping sewage / filtrate mixed with air (oxygen) immediately after the aeration tank in the purification system shown in FIG. The gas mass 64 staying in the central region 32 of the spiral chamber 30 can be effectively discharged without temporarily stopping the operation or providing a special exhaust means.

  Next, the vortex centrifugal pump 1 according to the second embodiment of the present invention will be described in detail with reference to FIGS. 9 and 10. In addition, description about the point which is common in 1st embodiment of this invention mentioned above is abbreviate | omitted, and it demonstrates centering on the point which is different from 1st embodiment.

  In the second embodiment of the present invention, as shown in FIGS. 9 and 10, the stirring member 40 extending from the inner wall surface 21 of the outer peripheral region 34 toward the substantially axis O (that is, extending substantially in the radial direction) is provided. It is characterized by being arranged in the outer peripheral region 34 of the spiral chamber 30.

  The stirring member 40 is a plate-like body that fits the inner wall surface 21 of the outer peripheral region 34 of the spiral chamber 30 and obstructs the swirling flow 60 </ b> A flowing through the outer peripheral region 34. The stirring member 40 is made of a material having rigidity and corrosion resistance (for example, a stainless material such as SUS304 or SUS316). One end of the stirring member 40 is fixed to the inner wall surface 21 at a position facing the discharge port 24. The other end of the agitating member 40 extends substantially toward the axis O and terminates in an outer peripheral region 34 that is slightly in front of the impeller 10. The stirring member 40 is fixed to the inner wall surface 21 by welding.

  Therefore, as in the first embodiment, the swirling flow 60A collides with the stirring member 40, and a part of the swirl flow 60 (axial flow 60C) crushes the gas mass 64 into a large number of minute bubbles 62. As a result, the swirl flow 60A including a large number of minute bubbles 62 is discharged from the discharge port 24, so that the volume of the gas mass 64 gradually decreases, and finally the gas mass 64 is completely discharged and the gas mass 64 disappears. To do. The vortex-type centrifugal pump 1 according to the second embodiment does not temporarily stop the operation of the pump even when lifting sewage / dirt mixed with air (oxygen) immediately after aeration, or special exhaust. Without providing any means, the gas mass 64 retained in the central region 32 of the spiral chamber 30 can be effectively discharged.

  Next, the vortex centrifugal pump 1 according to the third embodiment of the present invention will be described in detail with reference to FIGS. 11 and 12. In addition, description about the point which is common in 2nd embodiment of this invention mentioned above is abbreviate | omitted, and it demonstrates centering on the point which is different from 2nd embodiment.

  As shown in FIGS. 11 and 12, the third embodiment of the present invention extends from the inner wall surface 21 of the outer peripheral region 34 toward the substantial axis O (that is, generally extends in the radial direction), and the impeller. The stirring member 40, which terminates in the central region 32 existing immediately below 10, is disposed in the outer peripheral region 34 of the spiral chamber 30.

  The stirring member 40 is a plate-like body that fits the inner wall surface 21 of the outer peripheral region 34 of the spiral chamber 30 and locally closes the outer peripheral region 34 and also partially closes the central region 32. The stirring member 40 is made of a material having rigidity and corrosion resistance (for example, a stainless material such as SUS304 or SUS316). One end of the agitating member 40 is fixed to the inner wall surface 21 at a position facing the discharge port 24, and the other end of the agitating member 40 extends substantially toward the axis O and is located in the center immediately below the impeller 10. Terminate at region 32. The end position of the stirring member 40 in the central region 32 is appropriately determined according to the required stirring force.

  Therefore, as in the second embodiment, the swirling flow 60A collides with the stirring member 40 and a part of the spiral flow 60 (axial flow 60C) crushes the gas mass 64 into a large number of minute bubbles 62. As a result, the swirl flow 60A including a large number of minute bubbles 62 is discharged from the discharge port 24, so that the volume of the gas mass 64 gradually decreases, and finally the gas mass 64 is completely discharged and the gas mass 64 disappears. To do. The vortex-type centrifugal pump 1 according to the third embodiment does not temporarily stop the operation of the pump even when lifting sewage / dirt mixed with air (oxygen) immediately after aeration, or with special exhaust. Without providing any means, the gas mass 64 retained in the central region 32 of the spiral chamber 30 can be effectively discharged. Furthermore, since the stirring member 40 is approaching the gas mass 64 staying in the central region 32, the stirring action by the stirring member 40 becomes more effective.

  In addition, although the stirring member 40 which concerns on 1st embodiment thru | or 3rd embodiment mentioned above has a difference in shape, all are plate-shaped bodies extended in a substantially radial direction. However, the stirring member 40 according to the present invention is not limited to a plate-like body. For example, a lump that extends in a generally radial direction or a rod-like body that extends in a generally axial O direction is generally in a radial direction. A plurality of them may be arranged. Furthermore, a configuration may be employed in which a plurality of stirring members 40 extending substantially in the radial direction are provided in the outer peripheral region 34 of the spiral chamber 30.

  Furthermore, from the viewpoint of effective stirring, it is preferable that the stirring member 40 extends substantially in the radial direction. However, the stirring member 40 stirs the swirl flow 60 and the central region 32 of the swirl chamber 30. Therefore, it is not necessary for the stirring member 40 to extend substantially in the radial direction. That is, as long as the stirring member 40 exhibits the stirring effect, the stirring member 40 may extend in a direction substantially deviating from the radial direction.

1: Vortex type centrifugal pump 2: Motor 4: Motor shaft 6: Rotating shaft 8: Mechanical seal 10: Impeller 12: Blade 18: Support 20: Pump casing 21: Inner wall surface 22: Suction port 23: Suction passage 24: Discharge port 26: Discharge side flange 28: Suction side flange 30: Swirl chamber 32: Central region 34: Outer peripheral region 40: Stirring member 42: Opening 44: Flange 50: Connection member 60: Swirl flow 60A: Swirl flow 60B: Collision Flow 60C: axial flow 60D: anti-axial flow 62: bubble 64: gas mass O: axial

Claims (6)

A spiral chamber having an impeller that rotates about an axis and a pump casing that covers the impeller, and an internal space formed inside the pump casing forms a spiral flow by the rotation of the impeller In a vortex centrifugal pump comprising
A vortex centrifugal pump characterized in that a stirring member for stirring a spiral flow formed in the spiral chamber is disposed in an outer peripheral region of the spiral chamber.   2. The vortex centrifugal pump according to claim 1, wherein the agitating member extends from a discharge port provided at a terminal portion of the spiral chamber substantially toward an axial center.   The stirring member has a substantially semi-cylindrical shape fitted to the internal shape of the discharge port, and the opening of the substantially semi-cylindrical stirring member is disposed so as to face the spiral flow. The vortex type centrifugal pump according to claim 1 or 2.   The vortex centrifugal pump according to any one of claims 1 to 3, wherein one end of the stirring member has a flange, and the flange is attached to a flange portion of the discharge port. .   The vortex centrifugal pump according to any one of claims 1 to 4, wherein the agitating member extends from an inner wall surface of a pump casing forming a spiral chamber substantially toward an axial center.   The vortex centrifugal pump according to claim 1, wherein the stirring member extends to a central region of the spiral chamber.

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