JP5602816B2 - Pump equipment - Google Patents

Description

  The present invention relates to a pump facility that operates by forming a siphon in a siphon pipe connected to the discharge side of the pump.

  Pump equipment that operates by forming a siphon in the siphon pipe connected to the discharge side of the pump as a simplified pump equipment without the need to install valves such as a discharge valve in the pump main pipe ( Siphon type pump equipment) is known.

  FIG. 1 shows a conventional general pump installation of this kind. As shown in FIG. 1, the pump facility includes a pump 18 that pumps up water 16 in the suction water tank 14 by the rotation of the impeller 12 that is driven by the driving machine 10. One end of a siphon pipe 20 is connected to the discharge port of the pump 18, and the open end 22 of the siphon pipe 20 is located inside the discharge water tank 24 and is immersed in the water 26 stored in the discharge water tank 24. It is supposed to be.

  The siphon pipe 20 includes a rising pipe 28 that rises vertically, a top pipe 30 that extends horizontally at the top, a hanging pipe 32 that droops vertically, an upstream elbow pipe 34 that connects the rising pipe 28 and the top pipe 30, and a top pipe 30. It has a downstream elbow pipe 36 that connects the drooping pipe 32, and the air is introduced into the siphon pipe 20 at the top of the top pipe 30 when the operation is stopped to destroy the siphon, so that the suction water tank 14 side is reached. A siphon breaker 38 is provided to prevent backflow of the water. The siphon breaker 38 includes a siphon break pipe 40 that communicates with the top pipe 30 and an open / close valve 42 that includes an electric valve that opens and closes the pipe 40.

  As the top pipe 30, as shown in FIG. 2A, a circular pipe having a general-purpose cross section is generally used, but in particular, the pipe diameter (= pump diameter) is relatively large with 1000 mm or more. In the pump facility, the pipe top level PTL is lowered as much as possible to reduce the space and cost of the civil engineering structure, as shown in Fig. 2 (b). It is also widely used to have a flat rectangular tube.

In this example, in order to simplify the equipment, the siphon is formed in the siphon pipe 20 by the self-siphon operation of the pump 18 (the operation in which the actual lift is approximately the top of the siphon pipe). A method of operating the siphon pipe 20 with water by using a vacuum pump is also performed. In addition, a divergent pipe 44 that gradually expands downward is connected to the bottom of the drooping pipe 32, thereby reducing the discharge loss (v ² / 2g) and reducing the head loss. A straight pipe may be used instead of the pipe.

  In this pump facility, when the suction water tank 14 reaches a predetermined water level, the impeller 12 of the pump 18 is rotated by driving the driving machine 10, and the water 16 in the suction water tank 14 is siphoned. Through 20, water is pumped into the discharge water tank 24. The actual lifting height Ha when the siphon is formed in the siphon pipe 20 is the difference between the discharge water level and the suction water level. In addition, when the siphon is not formed in the siphon pipe 20 (during the formation process), the water pushed up by the pump 18 overflows to the upper part of the siphon pipe 20, and the actual lifting height Hb at that time is over the top of the siphon pipe 20. It is the difference between the water surface and the suction water level.

  In the initial stage of pump starting of the pump equipment that operates by forming a conventional siphon (= when the siphon is not formed), the pump is operating at a high head, that is, in a small water amount operation state, the flow velocity in the pipe is slow, and the air in the siphon pipe 20 Is in a state that is difficult to take. Then, after the pump is started, the in-pipe water level of the top pipe 30 rises, and as shown in FIG. 3, the in-pipe water level WL increases and reaches near the top level PTL (see FIG. 1). In such a state, the surface of the water flow in the pipe is a gentle flow, and the water flow is difficult to entrain the air remaining in the top pipe 30. For this reason, it takes a long time of about 5 to 10 minutes until all the air in the tube is finally discharged to form a siphon. Thus, if it takes a long time to form a siphon, in a drainage pump station with a rapid inflow, the siphon is formed and drained by the small water amount operation time (starting time) until the pump performs the rated (regulated) drainage operation. However, there is a risk of inundation damage and there is a strong demand for siphon formation (= operation at the rated drainage amount) as soon as possible.

Here, the water surface state of the flow of the open channel (having a surface in contact with the atmosphere) can be determined by the following Froude number Fr.
Fr = V / (gh) ^1/2
Where V: average flow velocity, g: gravitational acceleration, h: water depth (hydraulic water depth)

  As the Froude number Fr becomes closer to 0, the surface flow becomes gentler. For this reason, as shown in FIG. 3, when the water depth h in the top pipe 30 before the complete siphon formation is large, the value of the fluid number Fr becomes small and the water flow surface becomes a gentle flow state. For this reason, it becomes difficult for the water flow to entrain the air remaining in the top pipe 30.

  In addition, as described above, if the discharge valve is omitted for simplification, when the pump is stopped after the siphon operation by the pump, if the siphon break is not reliably performed by injecting air into the siphon piping, As a result, there is a risk of water flowing back into the water absorption tank and causing inundation damage, and there is a strong demand for ensuring reliability through a reliable siphon break.

  Usually, the siphon break pipe 40 of the siphon breaker 38 is provided in communication with the top pipe 30, and the siphon break pipe 40 is controlled to be opened and closed by an open / close valve 42 such as an electric valve, so Although the siphon breaks to prevent backflow when the pump stops, there is generally a single siphon break pipe, and there is a problem in reliability because there is a risk of dust adhering to the siphon break pipe. It was. Measures such as installing a plurality of siphon breakers 38 can be taken. However, if a plurality of siphon breakers 38 are installed in this way, there is a problem that the installation cost increases and the number of maintenance management devices increases.

  In order to solve the problem of the pump equipment that performs such siphon operation, a partition plate that is located near the top of the discharge pipe (siphon pipe) and divides the flow path in the discharge pipe into two paths is provided. Has been proposed to shorten the siphon formation time by providing a jet facility located upstream of the water flow, and guiding the water flow by the jet flow of the jet facility to one flow path partitioned by a partition plate to increase the flow velocity. (See Patent Document 1). However, in this case, a jetting facility is required separately, and a partition plate needs to be installed in the discharge pipe, so that not only the equipment cost (jet equipment + discharge pipe cost) is high, but also to the partition plate. Concerns about the entanglement of trash can be considered. If dust entangles with the partition plate, it may affect the water supply function of the pump, such as blocking of the discharge pipe.

  In addition, it has been proposed to shorten the siphon formation time by providing stepped shapes and protrusions with flow resistance function on the inner wall (lower surface) of the pipe located at the top and descending part of the siphon pipe. (See Patent Document 2). However, in this case, there is a problem that the siphon tube is not only expensive due to a special specification, but also dust is accumulated or entangled on a stepped shape or projection having a flow resistance function.

JP 05-288200 A JP 2001-208000 A

  The present invention has been made in view of the above circumstances, and provides pump equipment with improved maintainability, economy, and reliability in a pump equipment in which a siphon pipe forming a siphon is connected to the pump discharge side. For the purpose.

According to the first aspect of the present invention, in a pump facility in which a siphon pipe that forms a siphon is connected to a pump discharge side, a cross-sectional area of a top pipe that is horizontally disposed on the top of the siphon pipe is set in a fluid flow direction. The pump equipment is characterized by an increase along the line.
Thus, by increasing the cross-sectional area of the top pipe along the flow direction of the fluid, it is possible to generate a vortex portion in the fluid flowing along the top pipe and disturb the surface flow. In this case, obstacles (overhanging portions) can be completely eliminated in the top pipe, and the start-up time can be shortened without impairing the reliability of the pump equipment even when there is a lot of dust.

The invention according to claim 2 is the pump equipment according to claim 1, wherein the top pipe is a round rectangular tube having a circular inlet and a rectangular outlet .

  ADVANTAGE OF THE INVENTION According to this invention, in the pump installation which connected the siphon piping which forms a siphon inside to the pump discharge side, the pump installation which improved maintenance management property, economical efficiency, and reliability can be provided.

It is a schematic diagram which shows the conventional pump equipment. (A) is the sectional view on the AA line of FIG. 1, (b) is (a) equivalent drawing of another example. It is a figure which shows the principal part of FIG. 1 in the state which the pipe water level increased. It is a schematic diagram which shows another pump installation. It is the BB sectional view taken on the line of FIG. It is a schematic diagram which shows another pump installation. It is CC sectional view taken on the line of FIG. Furthermore, it is sectional drawing of the top piping in another pump installation. Furthermore, it is sectional drawing from which top piping in another pump installation each differs. It is a schematic diagram which shows another pump installation. It is the A section enlarged view of FIG. It is a schematic diagram showing pump equipment of an embodiment of the present invention. (A) is a left side surface of the top pipe of the pump facility shown in FIG. 12, (b) is a plan view, and (c) is a right side view. (A) is a left side surface of another top pipe, (b) is a plan view, and (c) is a right side view.

    The pump equipment of the present invention will be described below with reference to the drawings. 1 to 14, the same or corresponding members are denoted by the same reference numerals, and redundant description is omitted.

  4 and 5 show another pump facility. 4 and FIG. 5 is different from the example shown in FIGS. 1 to 3 as a top pipe 30 that is horizontally disposed on the top of the siphon pipe 20 and constitutes a part of the siphon pipe 20. As shown in FIG. 5, an elliptic tube 50 having an elliptical cross section with no corners is used with the major axis of the ellipse being horizontal. In other words, the elliptic tube 50 constituting the top pipe 30 eliminates the corners by connecting the upper surface and both side surfaces, and the lower surface and both side surfaces with curved surfaces each having a curvature radius r. Further, as the upstream elbow pipe 34 connecting the rising pipe 28 and the elliptic pipe (top pipe) 50, the rising pipe 28 made of a circular pipe and the top pipe 30 made of the elliptic pipe 50 are smoothly formed without having a corner portion. The connecting elbow pipe 52 is used. Other configurations are the same as the example shown in FIGS.

  According to this example, by using an elliptical pipe 50 having an elliptical cross section with the major axis horizontal as the top pipe 30, the value of the Froude number Fr is compared with the case where a circular pipe is used as the top pipe 30. In addition, when the impeller (impeller) 12 of the pump 18 is rotated to pump water, the discharge water containing the swirl component from the pump 18 is an elliptic tube (top pipe) 50 with the swirl component included. It can be made to flow inside. As a result, even when the water level reaches the vicinity of the top of the pipe, the air remaining in the elliptical pipe (top pipe) 50 is swept into the water flow by the swirl component and efficiently swept to the discharge side to form a complete siphon. The time required can be shortened.

6 and 7 show still another pump facility. 6 and 7 is different from the example shown in FIGS. 1 to 3 as a top pipe 30 that is horizontally disposed on the top of the siphon pipe 20 and constitutes a part of the siphon pipe 20. As shown in FIG. 7, a rectangular pipe 54 having a rectangular cross section is used with its long side being horizontal, and further, the downstream elbow pipe 36 is formed from an approximately half area downstream of the rectangular pipe 54 constituting the top pipe 30. The flat plate-like dividing plate 56 that divides the pipe cross-section up and down is installed horizontally and above the center of the cross-section of the pipe. Other configurations are the same as the example shown in FIGS.

According to this example, when the in-pipe water level immediately before the formation of the complete siphon is in a high state, an open water channel and a split channel 56 with the dividing plate 56 as the bottom surface are divided inside a rectangular pipe (top pipe) 54 having a rectangular cross section. A closed water channel with the plate 56 as the upper surface can be formed. As a result, in the upper part of the pipe where the residual air remains, an open channel having a shallow depth with the dividing plate 56 as a lower surface is formed, and the value of the Froude number Fr is set as compared with a normal pipe (a pipe without a dividing plate). It is possible to disturb the surface water flow, and even if the water level reaches the vicinity of the top of the pipe, the air remaining in the rectangular pipe (top pipe) 54 is entrained in the water flow and efficiently swept to the discharge side. The time required to form the siphon can be shortened. Further, by installing the dividing plate 56 above the center of the cross section of the rectangular pipe (top pipe) 54, it becomes difficult to get entangled with dust having the property of flowing on the lower surface where the flow velocity is slow, and it is possible to further increase the reliability. Become.

  Further, according to this example, after the siphon is formed in the siphon pipe 20, the dividing plate 56 functions as a rectifying plate. For this reason, the flow after siphon formation can be stabilized and it can be set as the pump installation with few piping losses (loss head).

As shown in FIG. 8, as the top pipe 30, an elliptical pipe 50 having an elliptical cross section without corners is used with the major axis of the ellipse being horizontal, and the inside of the elliptical pipe (top pipe) 50 is used. The flat plate-like dividing plate 56 that divides the pipe cross section vertically may be installed horizontally.

  FIG. 9A to FIG. 9C show cross sections of different top pipes, each using a deformed pipe whose cross section has the maximum cross section width above the pipe center as the top pipe 30. That is, FIG. 9A shows a trapezoidal shaped pipe 58 having a trapezoidal cross section whose upper side is longer than the lower side as the top pipe 30, and FIG. In FIG. 9C, the triangular shaped deformed tube 60 is used as the top pipe 30, and a deformed tube 62 having a wide portion 62 a wider at the upper portion than the lower portion is used.

  In this way, by using a deformed pipe whose cross-sectional width is maximum above the center of the pipe as the top pipe 30, the value of the Froude number Fr in the top pipe 30 is increased and the surface water flow is disturbed. Even when the water level reaches the vicinity of the top of the pipe, the air remaining in the top pipe can be entrained and efficiently swept to the discharge side, so the time required to form a complete siphon can be reduced.

That is, as described above, the feed number Fr is
Fr = V / (gh) ^1/2
(V: average flow velocity, g: acceleration of gravity, h: water depth (hydraulic water depth))
It is represented by

  Here, as shown in FIGS. 9 (a) to 9 (c), the hydraulic water depth h is defined as the free water surface width in a flow cross-sectional area (a) in the flow paths having different widths in the height direction. The value divided by T (h = a / T). That is, even in the case of the same flowing water cross-sectional area, the larger the free water surface width T, the smaller the hydraulic water depth h. As a result, the Froude number Fr becomes larger, and a turbulent surface flow can be formed. Become.

  10 and 11 show still another pump facility. 1 and 3 of the pump facility shown in FIGS. 10 and 11 is different from the example shown in FIGS. 1 to 3 in that an air outflow portion 64 is provided at the lower end of the siphon breaker pipe 40 that communicates with the top pipe 30 and constitutes the siphon breaker 38. It exists in the point which was made to project inside the top piping 30. FIG.

  In this manner, by providing the air outflow portion 64 at the lower part of the siphon break pipe 40 so as to project inside the top pipe 30, a vortex (Kalman vortex) is provided downstream of the air outflow section projecting into the top pipe 30. The surface water flow is disturbed and air remaining in the top pipe 30 can be easily caught in the water flow.

  Further, in this example, the air outflow portion 64 is formed of a substantially flat plate material 66, the plate material 66 is disposed in parallel to the water flow, and a plurality of air outlets 66a are provided in the plate material 66.

  As described above, the air outflow portion 64 is formed of the substantially flat plate material 66 and the plate material 66 is arranged in parallel to the water flow, so that long dust such as a piece of cloth is applied to the plate body (overhang portion) 66. It is possible to prevent the air outflow portion 64 from being wrapped and to make a state where the siphon can be surely cut when the pump is stopped. Thereby, it can be set as the reliable pump installation which does not have a possibility of the backflow by siphon break failure.

  In addition, by providing a plurality of air outlets 66a on the plate member 66, even if one of the air outlets 66a is blocked by dust such as silt, a siphon break function can be secured, and the reliability is higher. Pump equipment can be used.

  12 and 13 show a pump facility according to an embodiment of the present invention. The pump equipment of the embodiment shown in FIGS. 12 and 13 is different from the example shown in FIGS. 1 to 3 in that a top pipe 30 that is horizontally disposed on the top of the siphon pipe 20 and constitutes a part of the siphon pipe 20. As shown in the figure, a rounded tube 70 having a circular inlet port 70a and a rectangular outlet port 70b with a gradually increasing flow channel area is used, and the cross-sectional area of the top pipe 30 composed of the rounded tube 70 is aligned along the fluid flow direction. It is in the point to change.

  As described above, the round pipe 70 whose cross-sectional area is changed (increased) along the flow direction of the fluid is used as the top pipe 30, so that the fluid flowing along the round pipe (top pipe) 70 is vortexed. Can be generated to disturb the surface flow. In this case, obstacles (overhanging portions) can be completely eliminated in the top pipe, and the start-up time can be shortened without impairing the reliability of the pump equipment even when there is a lot of dust.

  As shown in FIG. 14, a rounded square tube 72 having a rounded corner changing part 72c is used at a predetermined position between a circular inflow part 72a and a rectangular outflow part 72b having a larger sectional area than the inflow part 72a. And you may make it generate a vortex | eddy_current part in this round angle change part 72c.

  Although the embodiment of the present invention has been described so far, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention may be implemented in various different forms within the scope of the technical idea. For example, siphon piping can be achieved by effectively using the swirl flow component of the pump, turbulent surface water flow due to fluid number design, and turbulent surface water flow due to overhangs or cross-sectional changes. It becomes easy to entrain (sweeping) the residual air inside, and it is possible to synergistically shorten the starting time.

DESCRIPTION OF SYMBOLS 10 Driver 12 Impeller 14 Water absorption tank 18 Pump 20 Siphon pipe 22 Open end 24 Discharge water tank 28 Rise pipe 30 Top pipe 32 Droop pipe 34 Upstream elbow pipe 36 Downstream elbow pipe 38 Siphon breaker 40 Siphon break pipe 42 Open / close valve 44 Suehiro pipe 50 Oval pipe (top pipe)
52 irregular elbow pipe 54 rectangular pipe (top piping)
56 Dividing plates 58-62 Deformed pipe (top pipe)
64 Air Outflow Portion 66 Plate Material 66a Air Distribution Hole 70, 72 Round Square Tube

Claims (2)

In the pump equipment where the siphon piping that forms the siphon inside is connected to the pump discharge side,
A pump facility characterized in that a cross-sectional area of a top pipe arranged horizontally at the top of the siphon pipe is increased along a fluid flow direction. 2. The pump equipment according to claim 1, wherein the top pipe is a round rectangular tube having a circular inlet and a rectangular outlet .

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