JP3656096B2 - Pre-swirling tank for submersible pumps - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a pre-swirl tank provided with a submersible pump and installed close to each other, and more particularly to a pre-swivel tank suitable for a submersible pump installed in a sewage manhole. It is.
[0002]
[Prior art]
A liquid containing suspended matter, sediment, etc., for example, sewage, is once stored in a manhole. When a predetermined amount is accumulated, it is sent to a sewage treatment plant by a submersible pump installed in a manhole. Such an apparatus for discharging a liquid using a submersible pump has been proposed by the present applicant in Japanese Patent Laid-Open No. 3-84136. This discharge device comprises a pre-swirl tank installed in the liquid. The pre-swirl tank has an overflow dam of a predetermined height, and an inflow groove that is inclined downward from the overflow dam toward the bottom of the pre-swirl tank is formed. Therefore, when the submersible pump installed in the pre-swirl tank is activated, the liquid is sucked from the suction pipe of the submersible pump. At this time, while the amount of liquid is large, pressure is applied by the head of water, so the liquid flows into the pre-swirl tank from the opening above the pre-swirl tank, and the liquid does not swirl in the pre-swirl tank. As the discharge progresses and the liquid level drops to the overflow weir, the liquid enters the pre-swirl tank as a swirling flow from the inlet passage and is sucked in while swirling. As a result, suspended matters, precipitates and the like are sucked and discharged simultaneously with the liquid.
[0003]
In the above-described discharge device proposed by the present applicant, the amount of liquid entering the pre-swirl tank from the inflow groove of the overflow weir is sufficiently secured. Therefore, there will be no hindrance to the discharge of suspended matter, sediment, etc. However, if the amount of liquid entering the pre-swirl tank from the inflow groove is small, a sufficient swirling flow cannot be obtained, and suspended matter, sediment, etc. may not be discharged. Therefore, a sewage pump system has been proposed in which the flow rate entering from the inflow groove is increased as much as possible. In this pump system, as shown in FIG. 3, the manhole 50 is provided with an overflow weir 51 at a position eccentric from the center in the radial direction. Swirl tanks 53 and 53 ′ are provided. As shown in FIG. 3B, inflow grooves 54 and 54 ′ extending from the overflow weir 51 to the bottom peripheral walls of the pre-swirl tanks 53 and 53 ′ are provided. And these pre-rotation tanks 53 and 53 'are provided with submersible pumps 60 and 60', respectively. In addition, the other reference numerals 65 and 65 in FIG. 3 indicate guide rods of the submersible pump 60, and 66 indicates a detachable fitting of the submersible pump 60, respectively.
[0004]
Therefore, when one of the submersible pumps 60 is activated, when the level of the sewage is at the upper position A, the sewage enters the pre-swirl tank 53 mainly from the opening of the pre-swirl tank 53 and is sucked into the suction pipe 61 and discharged. The liquid is discharged from the discharge pipe 63 to a predetermined position via the pipe 62. When the discharge proceeds and the liquid level reaches the B position at the top of the overflow weir 51, the sewage in the reservoir 52 flows from the inflow groove 54 into the pre-swirl tank 53. Since the inflow groove 54 extends to the bottom peripheral wall of the pre-swirl tank 53, that is, provided in the tangential direction of the pre-swirl tank 53, the sewage is sucked into the suction pipe 61 while turning in the pre-swirl tank 53. . As sewage swirls, suspended matter and sediments are sucked in at the same time as sewage.
[0005]
[Problems to be solved by the invention]
According to said pump system, since the storage part 52 is taken comparatively large, it can raise | generate a swirling flow. In addition, since the submersible pumps 60 and 60 ′ are provided in the pair of pre-swirl tanks 53 and 53 ′, respectively, by operating these submersible pumps 60 and 60 ′ alternately, the life of the pump is extended. The advantage that the submersible pump 60 or 60 'can be reserved is recognized.
However, there are problems to be improved. For example, since two pre-swirl tanks 53, 53 ′ must be provided in a manhole 50 of a predetermined size, there is a limit to enlarge the storage part 52, and a swirling flow is not necessarily generated. It is not possible to secure an amount sufficient to suck in sediments. In particular, when two submersible pumps having a diameter of 150 mm are installed in a No. 4 manhole having a diameter of 1800 mm, it is difficult to secure the storage unit 52 having a required size. Further, in order to enlarge the storage portion 52, the pre-swirl tanks 53, 53 ′ must be provided eccentric from the center of the manhole 50, so there is a problem in the installation layout of the pre-swirl tanks 53, 53 ′. Further, when one of the submersible pumps 60 is activated, suspended matter, sediment, and the like can be discharged from the pre-swirl tank 53 in which the submersible pump 60 is installed. Since suspended matter, precipitates, etc. remain in this, they may rot and emit a foul odor, which may contaminate the environment.
The present invention is intended to provide a pre-swirling tank for a submersible pump that solves the above-described problems. Specifically, even if the installation space is small, the pair of pre-swirling tanks is specially limited to the layout. A submersible pump that can be installed without any problems, and has sufficient amount of swirling flow necessary to discharge suspended matter, sediment, etc., and has few problems of spoilage of suspended matter, sediment, etc. The purpose of this is to provide a pre-swivel tank.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a pre-swirl tank provided with submersible pumps and installed close to each other, the pre-swirl tank having a peripheral wall And the bottom wall are formed so as to form a container shape, a communication hole is opened in a tangential direction in the peripheral wall in the vicinity of the bottom wall, and from the vicinity of the upper edge portion of the peripheral wall in the vicinity of the bottom wall . An inflow groove inclined toward the peripheral wall is provided, and when the pre-swirl tanks are installed close to each other, the pre-swirl tanks are separated from each other by a weir portion, and are communicated with each other by the communication hole and the inflow groove. It is configured.
The invention according to claim 2 is the pre-swirling tank according to claim 1, wherein the vicinity of the upper edge portion of the peripheral wall is a weir portion having a predetermined height higher than other portions, and the invention according to claim 3 The pre-swivel basin according to claim 1 or 2, wherein the pre-swirl basin is molded from fiber reinforced plastic so that they are placed symmetrically back to back, and the invention according to claim 4 The pre-swirl tank according to any one of Items 1 to 3, wherein the pre-swirl tank is installed in a manhole for sewage.
[0007]
[Action]
A pair of pre-swivel tanks are installed close to the bottom of a No. 4 manhole having a diameter of 1800 mm, for example. If it does so, while a pair of pre-swirl tank will be partitioned off by a weir part , it will mutually communicate by a communicating hole and an inflow groove . For example, a submersible pump having a diameter of 150 mm is installed in each of these pre-swirl tanks.
When a predetermined amount of liquid, that is, sewage accumulates in the manhole, for example, a level switch of the control device is activated and one of the submersible pumps is activated. Sewage is drawn from the suction pipe of the submersible pump and drained from the discharge pipe. When drainage proceeds and the water level drops to a predetermined position, the sewage in the other pre-swirl tank flows from the inflow groove and also flows as a swirl flow from the communication hole. As a result, a strong swirling flow is generated in the pre-swirling tank, and suspended matter, sediment, and the like are simultaneously sucked and discharged together with the sewage in the other pre-swirling tank. When a swirling flow is generated and the timer counts for a predetermined time, for example, or when the water level drops to an off level, the submersible pump is stopped by a signal from the control device.
When a predetermined amount of sewage accumulates again in the manhole, the other submersible pump is activated, and sewage, suspended matter, sediment, etc. are simultaneously sucked and discharged. Thereafter, the above operation is repeated and drained. According to the third aspect of the present invention, the operation is performed by the pre-swirl tanks installed symmetrically back to back, and in the fourth aspect of the invention, the operation is performed in the manhole for sewage.
[0008]
【Example】
Hereinafter, the example which applied the Example of this invention to the manhole for sewage is demonstrated. As shown in FIG. 1, the manhole 1 is constituted by a manhole inner wall portion 2 and a bottom wall portion 3 in a cylindrical shape. Level switches Us and Ls are provided at appropriate positions above and below the manhole inner wall 2. Further, as shown in FIG. 2A, a common discharge pipe 37 connected to the inflow pipe 36 and the discharge pipe 35 of the submersible pumps 30 and 30 ′ passes through the inner wall 2 of the manhole. Is provided. Further, well-known ladders 4, 4,... Are provided on the manhole inner wall 2.
[0009]
Since the pair of pre-swirl tanks 10 and 10 'installed on the bottom wall 3 of the manhole 1 are symmetrical, one pre-swirl tank 10 will be described below, and the other pre-swirl tank 10' will be described below. Do not duplicate the same reference number with a dash “'”.
As shown in the perspective view of FIG. 2B, the pre-swirl tank 10 is composed of a tank part 11 and a weir part 16. Although the tank part 11 is formed so that the whole may show a container shape from the surrounding wall 12 and the bottom wall 13, the diameter of an upper opening part is larger than the diameter of the bottom wall 13, and is expanded in taper shape. . Therefore, as will be described later, the sewage flowing into the pre-swirl tank 10 from the inflow groove of the dam portion 16 gathers at the center while turning, and is effectively sucked from the suction pipe of the submersible pump. Further, a protrusion 14 protruding upward is provided at the center of the bottom wall 13.
[0010]
The peripheral wall 12 near the bottom wall 13 of the pre-swirl tank 10 has a communication hole 15 that passes through the peripheral wall 12 and opens to the outside, as well shown in FIG. Opened in the tangential direction. That is, the direction of the communication hole 15 is the angle θ formed by the tangent S at the point where the communication hole 15 of the peripheral wall 12 is opened and the axis J of the communication hole 15 when the blade of the submersible pump described later rotates clockwise. Is selected to be smaller than 90 °. Therefore, when the submersible pump is driven and the sewage is sucked from the communication hole 15, the liquid flows into the pre-swirl tank 10 as a clockwise rotating flow or a swirling flow.
[0011]
The weir part 16 is higher than the horizontal hook part 17 at the upper end of the tank part 11 by a predetermined amount H. An inflow groove 20 having a downward slope from the weir portion 16 toward the bottom wall 13 is provided. The inflow groove 20 is formed by inner and outer walls 18 and 19 constituting a part of the peripheral wall 12 of the tank portion 11, and its bottom portion is substantially the same height as the flange portion 17 in the dam portion 16. And it surrounds the tank part 11 so that it may make about 1/2 round, and has reached the bottom wall 13. In addition, the inflow groove 20 in the dam portion 16 is opened toward the back side of the paper surface in the drawing. Therefore, when the pair of pre-swirl tanks 10 and 10 'are installed back to back as will be described later, the inflow grooves 20 and 20' communicate with each other.
[0012]
The pre-swivel tank 10 configured as described above is molded from fiber-reinforced plastic in a factory in this embodiment. Further, in this embodiment, the outer surface of the pre-swirl tank 10 is formed with concrete C or the like so that the bottom surface is horizontal, as shown in FIG. Therefore, the pair of pre-swirl tanks 10 and 10 'can be carried into the manhole 1 and easily installed so as to be back to back as shown in FIG. 1 and FIG. When installed, the communication holes 15 and 15 'of the pair of pre-swirl tanks 10 and 10' communicate with each other. The inflow grooves 20 and 20 ′ are also connected to each other at the highest weir portion 16. After the installation, the gap between the manhole inner wall 2 and the pre-swirl tank 10, 10 'is closed with concrete C' or the like. Further, as shown in FIG. 2A, the manhole 1 is divided into approximately equal parts by partition members 16 ″ and 16 ″ in which the weir portion 16 extends in the diameter direction.
[0013]
As is well known in the art, the submersible pumps 30, 30 ′ are carried into the manhole 1 by the respective guide rods 33, 33, 33 ′, 33 ′. Then, the discharge ports of the submersible pumps 30 and 30 ′ are connected to the respective discharge pipes 35 and 35 ′ by the detachable fittings 34 and 34 ′. Thereby, as shown in FIG. 1 and FIG. 2A, submersible pumps 30 and 30 ′ are installed in each of the pair of pre-swirl tanks 10 and 10 ′. At this time, the lower ends of the openings of the suction pipes 31 and 31 ′ are located directly above the protrusions 14 and 14 of the pre-swirl tanks 10 and 10 ′.
[0014]
Next, the drainage action of the above embodiment will be described. When sewage flows from the inflow pipe 36 and the upper level switch Us detects this, one submersible pump 30 is activated by a signal from the control device. In this state, since the head of the sewage is large, the sewage is supplied directly into the tank part 11 from the open part above the pre-swirl tank 10, and the sewage is sucked up from the suction pipe 31 without turning, and the discharge pipe 35 To a sewage treatment plant through a common discharge pipe 37.
[0015]
The drainage proceeds, the liquid level drops below the weir 16, and the sewage in the other pre-swirl tank 10 ′ flows into the pre-swivel tank 10 from the inflow grooves 20 ′, 20 until reaching the horizontal trough 17 . In addition, since the water level of the pre-swirl tank 10 is lowered and the head is small, the water flows from the communication holes 15 'and 15. The inflow groove 20 is formed by inner and outer walls 18 and 19 constituting a part of the peripheral wall 12 of the tank portion 11, and the communication hole 15 is opened in the tangential direction of the peripheral wall 12, so that the sewage is pre-swirl tank 10 is sucked up from the suction pipe 31 while being swirled and swirled as a strong swirl flow. Therefore, suspended matter, sediment, etc. are simultaneously sucked and discharged. When the off-level is reached, the submersible pump 30 stops with time up.
As time elapses, the amount of sewage flowing into the manhole 1 from the inflow pipe 36 increases, and when the upper level switch Us detects this, the other submersible pump 30 'operates in the same manner. Hereinafter, the pair of submersible pumps 30 and 30 ′ are alternately operated and drained.
[0016]
The present invention is not limited to the above embodiments, and can be implemented in various forms. For example, in the above embodiment, since the weir portion 16 that is higher by the predetermined amount H than the horizontal ridge portion 17 is provided, a large amount of sewage for swirling is ensured, but the volume of the pre-swirling tanks 10, 10 ′ is sufficiently large. Therefore, the swirl flow can be sufficiently generated without providing the exceptionally high weir portion 16. Therefore, the present invention can be implemented without the dam portion 16. In addition, the inflow grooves 20 and 20 ′ can be provided from the position of the lower horizontal hook 17 even without the weir 16 higher than the horizontal hook 17 by a predetermined amount H. Further, depending on the installation layout, the pair of pre-swirl tanks 10 and 10 'can be installed apart from each other. At this time, pipes are interposed in the communication holes 15 ′ and 15 and the inflow grooves 20 and 20 ′ are also connected through appropriate groove-shaped members. Furthermore, the pre-swirl tank 10 can be divided and molded, and can be integrated by connecting, for example, at a factory or an installation site.
In addition, although the said Example demonstrated the example in which a pair of pre-swirl tanks 10 and 10 'are applied to the manhole 1, this invention is applied also to drainage facilities, such as a sewage treatment plant, a chemical factory, a paper mill, and a pig farm. Obviously, the same applies.
[0017]
【The invention's effect】
As described above, according to the present invention, the pre-swirl tank is formed so as to form a container shape as a whole from the peripheral wall and the bottom wall, and the communication hole is opened in the tangential direction in the peripheral wall near the bottom wall. In addition, an inflow groove inclined toward the peripheral wall in the vicinity of the bottom wall is provided from the vicinity of the upper edge of the peripheral wall, and when the pre-revolving tank is installed close to each other, the pre-revolving tank is partitioned by a weir part. In addition, since it is configured to communicate with each other by the communication hole and the inflow groove, when one of the submersible pumps is driven to drain the water and the water level is lowered to a predetermined position, the liquid in the other pre-swirl tank flows in. It flows in as a swirling flow from the groove and eventually flows as a swirling flow from the communication hole. In this way, it flows in as a strong swirl flow. Since the volume of the pre-swirl tank is relatively large, the amount of inflow at this time is large. Therefore, according to the present invention, even if it is installed in a small place such as No. 4 manhole, the amount of the liquid swirling for a sufficient time required to discharge the suspended matter floating in the liquid, the settled sediment, etc. The effect peculiar to this invention that it is ensured is acquired. At this time, since the liquid in the other pre-swirl tank flows from the communication hole, the suspended matter, sediment, etc. in the other pre-swirl tank are also discharged at the same time, and there are few problems of decay of the suspended matter, sediment, etc. Furthermore, simply installing the pre-swirling tanks in the vicinity of each other ensures an amount of sustaining the swirling flow for a sufficient period of time, so that there is an effect of obtaining a degree of freedom in the installation layout of the pre-swirling tanks.
According to the invention described in claim 2, since the vicinity of the upper edge portion of the peripheral wall is the weir portion having a predetermined height, a large amount of liquid for swirling flow can be secured. Therefore, it is possible to obtain an effect that the suspended matter, precipitate, etc. can be discharged more completely. According to the third aspect of the present invention, since the pre-swirl tank is formed from fiber reinforced plastic, in addition to the above effects, an effect can be obtained in which installation work at the site can be performed by placing concrete or the like. Further, since they are installed symmetrically back to back, the number of molds for forming the pre-swirl tank can be reduced, and the pre-swirl tank can be obtained at a low cost.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of the present invention installed in a manhole.
2A and 2B are views showing an embodiment of the present invention, in which FIG. 1A is a top view of FIG. 1 and FIG. 2B is a perspective view of a pre-rotation tank.
FIG. 3 is a view showing a conventional example, in which (a) is a cross-sectional view thereof and (b) is a top view thereof.
[Explanation of symbols]
1 Manhole 10, 10 'Pre-rotation tank 15, 15' Communication hole 16, 16 'Weir part 20, 20' Inflow groove 30, 30 'Submersible pump

Claims (4)

A pre-swirling tank provided with submersible pumps and arranged in close proximity to each other,
The pre-swirl tank is formed so as to have a container shape as a whole from the peripheral wall (12) and the bottom wall (13), and a communication hole is opened in a tangential direction in the peripheral wall (12) in the vicinity of the bottom wall (13). And an inflow groove inclined from the vicinity of the upper edge of the peripheral wall (12) toward the peripheral wall in the vicinity of the bottom wall (13) is provided.
When the pre-swirling tanks are installed close to each other, the pre-swirling tanks are separated from each other by a weir portion (16, 16 ') and communicated with each other by the communication hole and the inflow groove. Pre-swirling tank. The pre-swirl tank for submersible pumps according to claim 1, wherein the vicinity of the upper edge of the peripheral wall (12) is a weir part having a predetermined height higher than other parts.   The pre-swirl tank for submersible pumps according to claim 1 or 2, wherein the pre-swivel tank is formed from fiber-reinforced plastic and installed symmetrically back to back.   The pre-swirl tank according to any one of claims 1 to 3, wherein the pre-swivel tank is installed in a manhole for sewage.

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