JP3306453B2 - Underground drainage facility - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an inflow channel (especially a small one) provided underground (especially underground with a large depth of about 15 to 60 m), such as rainwater, flowing into a waterway including a small river. Large underground drainage channel)
This is related to underground drainage facilities where the collected inflow water is guided to a drainage pumping station and discharged to rivers, etc. where it is discharged.In particular, the power of drainage pumps in large underground drainage facilities is reduced, the volume of pump wells is reduced, and drainage is reduced. The present invention relates to an underground drainage facility suitable for countermeasures against a delay in following upflow of upstream inflow water when a pump is started or upsurge when a pump is stopped.

[0002]

2. Description of the Related Art In recent years, a large-scale underground drainage facility has been planned, and an inflow water channel having a large sectional area is buried in a deep place underground for a long distance. In particular, deep underground utilization is being put to practical use. Here, the deep underground refers to a solid ground in a deep part where there is no influence on an upper structure, and a space approximately 50 m or less below the ground surface.

Conventionally, compared with such a large-scale underground drainage facility, the inflow water channel is not so deep and the distance is short, so that the open channel operation (flow down at a water level where there is a space above the sewer). ) Drainage systems were the mainstream. There is also a concept of closed channel operation (flow down the sewer in a full state) and open / close coexistence, but both had storage tanks to provide a storage effect.

[0004]

When a drainage pump is installed in the above-mentioned conventional open channel operation, a large-capacity, high-head pump is required, and the capacity of the prime mover is also increased. Also, the discharge side valve needs to have a large diameter and high pressure, and the driving device for opening and closing the valve also becomes large.

As described above, when a large-scale underground drainage facility is constructed on an extension of a conventional relatively small-scale underground drainage facility, not only the construction cost but also the running cost increases, which is uneconomical.

In addition, in the case of coexistence of opening and closing and operation of a closed channel, since the storage effect is reduced, it is necessary to provide a storage tank or increase the volume of the pump well, which also increases the construction cost.

Further, since the inflow water channel becomes very long, the water on the upstream side cannot follow immediately even if the drainage pump is operated.
In the method of operating the drainage pump, there is a problem that the downstream river or the like overflows and the downstream following is delayed.

On the other hand, in the underground drainage facilities, the drainage of the planned water amount is performed in response to the rapid increase of the inflow amount due to rainfall. Therefore, before the inflow water reaches the pump well, that is, when the water level in the pump well is low. A so-called standby operation for starting operation of the drainage pump is required. In such a standby operation, or in accordance with a change in the inflow amount, it is desired to easily and economically adjust the discharge amount of the drainage pump. As a means for satisfying such demands, there has been known a vertical shaft movable blade pump in which the blade angle of a pump impeller is variable (Japanese Patent Application Laid-Open No. 57-186092).

[0009] However, the conventional vertical movable blade pump is used for a circulating pump having a relatively low head (for example, about 30 m or less), but has a high head with a total head of 50 to 60 m and a large capacity. It is not used for drainage pumps for the following reasons.

(1) When the total head becomes higher, the fluid force applied to the movable blades increases accordingly, so that the load applied to the blade angle operating mechanism for adjusting the blade angle of the impeller increases, and the blade angle operating mechanism becomes It becomes large. On the other hand, since the blade angle operating mechanism has a size limitation that it must be housed in a limited space in the impeller hub, the allowable load of the blade angle operating mechanism is also limited. Therefore, the movable blade pump cannot be directly applied to a drain pump having a large total head and a large capacity.

(2) If the total head becomes high, the specific speed Ns expressed by the following equation (1) must be set to a lower value than in the prior art, so that there is a problem that efficiency and suction performance are reduced. That is, in Equation 1, the pump rotation speed N is determined by the suction pressure and the cavitation condition, and the discharge amount Q and the head H are given from the drainage plan.
Becomes higher, the specific speed Ns must necessarily be set to a lower value.

[0012]

(Equation 1)

However, the movable impeller is generally rotatably supported by a hub supported by a drive shaft, and is rotated around the axis to adjust the blade angle. And the hub surface on the drive shaft side must be formed as concentric spherical surfaces in accordance with the inner surface of the casing and the outer surface of the hub, respectively. Due to such restrictions on the shape, there is a problem that the efficiency and the suction performance are reduced when the specific speed is reduced.

An object of the present invention is to solve the above-mentioned problems of the prior art, and a first object is to provide an underground drainage facility capable of reducing running costs and construction costs by reducing the power of a drainage pump. It is to provide a drainage pump operation method.

A second object of the present invention is to provide a highly reliable underground drainage facility in which rivers and the like on the upstream side do not overflow even if a delay in following the inflow water on the upstream side or an upsurge at the time of stoppage of the drainage pump occurs. Is to do.

[0016]

[0017]

In order to achieve the first object, the underground drainage facility according to the present invention is provided with a deep underground slope.
A small, large-capacity inflow channel is provided, and
Drainage from various distribution channels near the surface and the surface via shafts
And distribute the water collected in the inflow channel to one of the inflow channels.
To drain water from rivers and the sea from the pumping station
In the constructed deep underground drainage system, the pump
The pump is located deeper from the ground than the pump design point
A pump is installed, whereby the inflow channel is closed
In this state, the planned water volume can be drained, and the pump
When the intake channel is in the open channel condition,
The specifications are set so that it can be drained with a small capacity
It is characterized by the following .

Further, the drain pump may be a movable blade pump or a rotation speed control pump to enable standby for drain.

As another means, the drainage pump is divided into a small-capacity high-head pump and a large-capacity low-head pump, and they are arranged at positions where the planned water flows out in the open channel and the closed channel, respectively. It is characterized by standby operation.

In order to achieve the second object, the underground drainage facility of the present invention determines the height of the overflow weir on the inflow side river, culvert, discharge channel, etc. from the maximum water level, and determines the underground inflow waterway. It is characterized by the introduction of water.

Further, as another means, the inflow shaft on the upstream side with respect to the pump is made relatively large with respect to the inflow amount.

[0022]

[0023]

According to the present invention, the object can be achieved by the following operation.

First, since the pump specifications of the drainage pump are determined so that the planned amount of water can be drained in the closed channel instead of the open channel, the total head of the pump can be small and the power for draining the same amount of water can be reduced. Becomes smaller. In this case, the operation in the closed channel system has a smaller buffer effect than that in the open channel, so that if the pump well water level rises quickly and the time until the pump starts is long, water may overflow.

On the other hand, by using a movable blade as the pump, the pump well is started with the blade angle fully closed (minimum blade angle) before the water in the pump well rises or when the water starts rising, and the pump well is started. This can be dealt with by opening the blade angle in accordance with the rise in water level and operating the pump well to keep the water level constant. In addition, by using a movable blade pump, the initial discharge water amount can be reduced, and if a weir is provided on the discharge side, the discharge valve can be eliminated.

Further, the start timing of the movable blade pump is monitored not only by the water level of the pump well but also by monitoring the water level of the inflow shaft on the upstream side, thereby preventing flooding on the upstream side. It is possible to reduce upsurge at the time of stoppage.

This is also possible when the pump is a rotation speed control pump. It is sufficient to start the pump at a low speed and raise the rotation speed by raising the pump well water level.

Instead of using a movable blade pump, it is also possible to separately install a small capacity high head pump and a large capacity low head pump. That is, it is possible to perform the operation from the standby operation with the blade angle fully closed to the small amount of drainage by performing the drainage operation after the pump well water level rises with the large-capacity low-lift pump using the small-capacity high-head pump. Of course, this can be achieved by increasing the capacity and head of the pump in three or four stages depending on the plan of the underground drainage facility. Next, set up overflows in the rivers, sewers, and drains on the inflow side, and set the height of this crest to the amount of water corresponding to the upsurge when the pump is stopped, and the maximum water level of each river, sewer, and drain. If it is set low, even if an upsurge occurs when the pump is stopped, it is possible to keep each pump within the maximum water level.

It is also conceivable that, after the operation of the pump, it takes tens of minutes for a long distance before the water in the inflow channel immediately below each overflow crest starts to move. On the other hand, the water in the inflow channel can start moving within the maximum water level by lowering the crest height from the maximum water level by the amount of water corresponding to the inflow amount during this period.

Further, this can be achieved by making the inflow shaft relatively large with respect to the inflow amount so as to have a buffer effect on the upstream side, since the follow-up of water becomes worse on the upstream side.

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

An embodiment of the present invention will be described below with reference to FIG.

As shown in the figure, drainage flowing into small rivers, sewers, drainage channels, etc. on the ground surface is supplied to inflow waterways (underground large waterways, underground waterways) connected via inflow shafts 1, 2, and 3. Flow into 4. The drainage flowing into the inflow channel 4 flows down to the pump well 6 of the pump station, is pumped by the pump 7, and is discharged from the discharge pipe 10.
After that, it is drained to the major river where it is discharged. The inflow channel 4 is provided with an air hole 5 as appropriate.

The characteristic specification of the pump 7 is determined so that a predetermined planned water volume can be drained on condition that the inflow water flows down the inflow water channel 4 in a full state, that is, a so-called closed water channel operation.

When water flows in from the inflow shafts 1, 2, 3 and the inflow channel 4 becomes full and becomes a closed channel, the water level of the pump well 6 rises and the actual head of the pump 7 decreases, so the state of the open channel is reduced. It becomes smaller than when draining the planned amount of water.

[0041] FIGS. 2 (a) and 2 (b) is a diagram for comparing the operation state of the pump of both, the pump P ₁ is to be able to plan water discharged in open water channel, actual head is H ₁
Is necessary and the power becomes large. In contrast, since the pump P ₂ is with the capability planning water in閉水path, actual head dwelt in H _2, the power is also reduced.

Due to the tendency of the characteristic curve QH of the pump, the installation position of the pump 7 is determined so that the shut-off operation is not performed even at the maximum actual head as shown in FIG. Is good. If the pump installation position is determined so that the planned water volume flows through the closed channel, the power can be significantly reduced.

Next, if the pump 7 in FIG. 1 is replaced by a movable blade pump, a further great advantage can be obtained. The movable blade pump requires a small amount of power when the blade angle is set near the minimum, so that continuous operation is possible even in the shutoff operation. Therefore, standby operation becomes possible.

[0044] Now, FIG. 3 (a), the blade angle When the inflow water channel 4 starts the pump at the minimum blade angle in a state level L ₁ of the open channel, the water level rises to the level L ₂ reached in FIG. 3 (b) Open. The operating point shifts from 1 → 2 → 3 → 4 → 5 in FIG. If the inflow further increases, the water level rises and the actual head decreases, so the operating point shifts from 5 to 6 and the planned water discharge is reached. Normally, the blade operation of the movable blade pump is fully closed in about 1 to 3 minutes →
Since the fully open operation is possible, if the pump is operated in a standby state in the state of the open channel, the size of the pump well can be determined so that the HWL does not become HWL until the blade angle becomes fully open. Can be small. Also, since the blade angle is small at the time of initial drainage, the discharge amount is small, so there is no need to attach a discharge valve as in the past, and a system can be created simply by providing a crest in front of the discharge side on the discharge side. it can. This is advantageous for a large-scale one, and a large-diameter, high-pressure discharge valve can be omitted.

As a method of starting the movable blade pump, it is possible to monitor not only the water level of the pump well but also the water level of the upstream inflow water channel and the inflow shaft, and start the pump by raising the water level. In a large-scale underground drainage facility, the distance between the pump 7 and the inflow shaft is large, and even when the pump is started, it may take tens of minutes for the water near the inflow shaft to move. As a countermeasure, as described above, when the water level of the inflow shaft starts to rise, the pump is started to start small-amount drainage, whereby flooding due to delay in following can be prevented.

In addition, when the pump is stopped, an upsurge may occur in the inflow water channel system when the pump is stopped. It is also conceivable that flood channels and the like overflow. This is a movable wing pump,
By stopping after performing standby operation near full closure while gradually closing the blade angle, it is possible to significantly reduce the upsurge of the inflow water channel system. The above effects can also be achieved by using the pump 7 as a rotation speed controlled pump. That is, low speed start up with the level L ₁ of the inflow water channel 4 open channel, it is sufficient to increase the rotational speed reaches the level L _2.

Further, even at the time of stoppage, by stopping after performing standby operation at low speed, it is possible to reduce the upsurge of the inflow water channel system.

Here, an embodiment of a movable blade pump suitable for the pump 7 of FIG. 1 will be described with reference to FIGS. FIG.
Is an enlarged elevational view around the pumping station, and FIG. 6 is a sectional view of the movable vane pump. As shown in those figures, the pump 7
A vertical multi-stage movable blade pump in which two vertical mixed-flow movable blade pumps 7a and 7b are connected in two stages is used. The suction port of the lower movable blade pump 7a is connected to the pump well 6 through an elbow-shaped suction pipe 21, and the discharge port is directly connected to the upper movable blade pump 7b. The discharge port of the movable vane pump 7b is connected to the discharge pipe 10 via a discharge elbow pipe 22, and is opened to a large river to be discharged. The drive shaft of the pump 7 is drawn upward from the discharge elbow pipe 22 and connected to the drive unit 23 via a coupling. The drive shaft is formed in a hollow shape as described later, and a blade angle operation shaft is inserted through the hollow portion. A blade angle control device 24 is connected to an upper end of the operation shaft. Here, the embodiment of the mixed flow movable blade is shown, but an axial flow type blade may be used.

Next, the structure of each movable blade pump 7a, 7b will be described with reference to FIG. Movable wing pump 7 as shown
The main parts a and 7b have the same configuration. Therefore, components having the same functions and configurations are denoted by the same reference numerals and description thereof will be omitted, and only the differences between the movable blade pump 7b will be described. The outer shell of the movable vane pump 7a includes an outer casing 31 and a casing liner 32 connected to a suction side of the outer casing 31.
Thus, a rotationally symmetric shape is formed. Inside the outer casing 31, a rotationally symmetric inner casing 33 is fixed by guide vanes 34 with the rotationally symmetric axis coincident. A hollow drive shaft 35 is disposed inside the inner casing 33, and is supported by the inner casing 33 via a bearing 36. An impeller hub 37 is attached to the lower end of the drive shaft 35 by flange connection. The outer peripheral edge of the impeller hub 37 is slidably attached to the outer periphery of the lower end of the inner casing 33 via a water seal member. The impeller hub 37 has a plurality of impellers 38 extending toward the inner surface of the casing liner 32.
Is attached. Each impeller 38 is attached to the impeller hub 37 via a stem 41 supported by two bearings 39 and 40 so that the blade angle can be changed.
An impeller hub cover 42 extending from the inner casing 33 is attached to the suction side of the impeller hub 37. The operation shaft 43 is inserted into a through hole provided in a hollow portion of the drive shaft 35 and a center portion of the impeller hub 37.
A spider 44 is attached to a lower end of the operation shaft 43. The spider 44 is connected to an arm 45 attached to the stem shaft 41 by a turnbuckle 46 via a ball joint. The arm 45, the turnbuckle 46, and the ball joint constitute a link mechanism that converts the vertical linear motion of the operation shaft 43 into the blade angle rotation motion of the impeller 38. This link mechanism is of a well-known type (for example, see JP-A-1-18739).
9 is applicable, the illustration of the detailed configuration is omitted.

A movable vane pump 7b having casings 31 and 32 having the same configuration is connected to the upper portion of the movable vane pump 7a thus formed. The upper end of the drive shaft 35 of the movable blade pump 7a is connected to the impeller hub 37 of the movable blade pump 7b by a flange or the like. In addition, the movable blade pump 7
The upper end of the operating shaft 43 of FIG.
The lower end of 3 'is connected by a screw coupling 47. That is, male threads cut at the ends of the operation shafts 43 and 43 'are screwed and connected to the coupling 47 having female threads. Drive shaft 3 of upper movable blade pump 7b
5 'and the upper end of the operation shaft 43' are drawn straight up from the discharge elbow pipe 22 as shown in FIG. 5, and are connected to the driving machine 23 and the blade angle control device 24, respectively. The blade angle control device 24 includes an actuator for moving the operation shafts 43 'and 43 in the axial direction. As this actuator, a hydraulic or pneumatic cylinder, an electric motor or the like is used.

The operation of the vertical-shaft multistage movable blade pump having the above configuration will be described. First, the basic operation will be described. When the operation of the driving device 23 is started, the upper driving shaft 35 ′ and the impeller hub 37 are driven.
, The upper impeller 38 rotates. At the same time, the lower impeller 38 rotates via the lower drive shaft 35 connected to the upper impeller hub 37 and the impeller hub 37. Thereby, the inflow water in the pump well 6 is sucked from the suction elbow pipe 21, and the sucked pumped water is discharged to the large river via the discharge pipe 10. At this time, each movable blade pump 7a,
Since 7b is connected in series, the total head of the pump 7 is the sum of the total heads of the pumps 7a and 7b. In other words, the total head of each pump 7a, 7b may be smaller than the required head determined from the drainage plan,
For example, about 1/2 is sufficient. Therefore, the load applied to the impeller 38 is reduced accordingly, and the load applied to the blade angle operating mechanism can be reduced. As a result, since the constituent members of the blade angle operating mechanism have the same size as the conventional one, they can be incorporated in the impeller hub 37, and since the total head per stage is small, the specific speed can be maintained large. Compared with a movable vane pump with a stage, a movable vane pump that avoids cavitation, is highly efficient, and is suitable for high head and large capacity applications can be realized.

Next, the operation of the blade angle will be described. When the operating shafts 43 and 43 'are displaced in the axial direction by the blade angle control device 24, the blade angles of the impeller 38 are simultaneously adjusted in the opening and closing directions through the spider 44, the turnbuckle 46, and the arm 45 in the upper and lower stages. . Thereby, the discharge amount of the pump 7 can be varied over a wide range, and the pump performance can be largely adjusted. Therefore, it is suitable to be applied to a standby operation or an underground drainage facility having a large fluctuation in the amount of inflow water.

In the vertical multi-stage movable blade pump shown in FIG. 6, the blade angle of the impeller 38 of the lower movable blade pump 7a is slightly (for example, smaller than the blade angle of the impeller 38 of the upper movable blade pump 7b). , About 1-2 degrees)
It is preferable to set the axial positional relationship between the operation shafts 43 and 43 'or the spider 44. This has the following advantages.

(1) Even when the blade opening of the upper pump 7b is in the minimum closed state, the blade opening of the lower pump 7a is slightly open, so that the suction pressure of the upper pump 7b can be maintained at a certain level or more. Therefore, cavitation of the upper pump 7b due to a decrease in suction pressure can be reliably prevented.

(2) Generally, the larger the blade angle is, the better the cavitation performance at a large flow rate is. Therefore, it is suitable when the pump 7 is used at a larger flow rate side than a design point. Although the cavitation performance of the upper pump 7b deteriorates on the large flow rate side, cavitation does not pose a problem in this embodiment because the suction pressure of the upper stage is increased by the lower stage.

(3) When the blade angle is changed, the flow rate at which a specific fluid stall or backflow occurs at a small flow rate changes. However, by providing a difference between the upper and lower blade angles, the upper and lower pumps 7a,
Since both stalls and backflow can be prevented from occurring simultaneously in both cases, stable operation can be performed even with a small flow rate.

Further, according to the vertical multi-stage movable blade pump shown in FIG. 6, the casing, the drive shaft, the operation shaft and the like are divided for each stage and they are connected by a joint such as a flange. Easy to assemble and disassemble. That is, when assembling the pump, first, the upper movable blade pump 7 b is assembled while leaving the casing liner 32. Next, the lower operation shaft 43 is connected to the upper operation shaft 43 ′.
After that, the lower drive shaft 35 is joined to the upper impeller hub 37. Next, after attaching the upper casing liner 32, the movable blade mixed flow ball portion of the lower movable blade pump 7a is assembled. When disassembling the pump, the movable blade mixed flow ball portion, the drive shaft 35, and the operation shaft 43 of the lower movable blade pump 7a are reversed in the reverse order.
After removal, the upper movable blade diagonal flow section is disassembled.

FIG. 7 shows another embodiment of the vertical axis multistage movable blade pump. In the present embodiment, the movable blade pump at the lower stage of the embodiment of FIG. 6 is replaced with a fixed blade vertical shaft pump 7c. The upper movable blade pump 7b has the same configuration as that of the embodiment of FIG. 6, and the lower fixed blade pump 7c fixes the blade angle of the impeller 50 to an impeller hub 49 that is rotatably provided with respect to the inner casing 33. Attached.

Also in this embodiment, since the movable blade pump 7b is connected in series to the fixed blade pump 7c, the total head of the pump 7 is the sum of the total heads of the respective pumps 7b and 7c. Therefore, the present invention can be applied to a pump having a higher total head than a single-stage movable blade pump. Further, according to this embodiment, the structure of the pump is simpler than that of the embodiment of FIG. 6, and the operating force of each blade can be reduced. On the other hand, changes in pump performance due to blade angle adjustment are small. Note that the upper stage and the lower stage in the embodiment of FIG. 7 can be exchanged, and the upper stage can be a fixed wing. In this case, there is a problem of cavitation in the upper stage when the movable wing in the lower stage is operated near the closed position.

Although the embodiments shown in FIGS. 6 and 7 all use the vertical mixed-flow pump, the vertical axial-flow pump may be used. Further, the number of stages of the movable vane pumps connected in series is not limited to two, and may be appropriately selected according to the planned head.

FIG. 8 shows an embodiment in which the pump 7 of the embodiment of FIG. 1 is configured by combining a small-capacity high-head pump 8 and a large-capacity low-head pump 9 in place of the movable blade pump. Similar effects can be obtained by operating the movable blade pump near the fully closed blade angle of the embodiment with a small-capacity high-lift pump and operating near the fully opened blade angle with a large-capacity low-head pump. FIG. 9 shows the operating characteristics of the pump. Although two types of pumps are shown here, it goes without saying that several types of pumps may be installed in any number of stages.

Next, the effect on the upsurge when the pump is stopped and the time delay from when the pump is operated to when the water in the inflow channel starts to move will be described.

The drainage from the river flows over the weir and flows into the inflow shaft 1. At this time, the crest height is the highest level of the river even if the amount of water due to the upsurge when the pump is stopped or the inflow corresponding to the time until the water in the inflow channel immediately below the overflow after the pump operation starts flowing into the river is reached. The height is determined so as not to reach the water level. By doing so, there is no need to worry about flooding or the like even with an upsurge caused by stopping the pump or a delay in following the water due to a long inflow channel. Also, the buffer for the entire underground drainage facility can be small.

FIG. 10 shows another embodiment for preventing flooding due to a delay in following the water in the inflow channel. Since the following of the water becomes worse toward the upstream side with respect to the pump 7, the relative amount to the inflow amount such as the upstream side is reduced. The inflow shaft is enlarged to provide a buffer effect.

As described above, according to each embodiment of the underground drainage facility of the present invention, (1) since the pump is installed at a position where the planned amount of water can be drained in the closed channel, the power can be reduced.

(2) Since the pump is on standby for drainage,
Buffers for underground drainage facilities such as pump wells can be small.

(3) When the pump is started, a small amount of water can be drained, so that a discharge valve is not required.

(4) The delay in following the inflow channel when the pump is started and the upsurge when the pump is stopped can be reduced, so that problems such as flooding are eliminated.

(5) Since the inflow into the shaft is performed by overflowing, the river, the culvert, and the spillway can be used as buffers, and the buffer for the flood problem solving and underground drainage facilities can be reduced.

(6) Since the buffer effect is relatively large on the upstream side with respect to the pump, problems such as flooding are eliminated.

FIG. 11 shows the actuator of the blade angle control device of the vertical multi-stage movable blade pump shown in FIG.
FIG. 3 is a cross-sectional view of an embodiment housed in an inner casing 33 of FIG. As shown, the upper movable blade pump 7b
A hydraulic cylinder 55 is provided above the impeller hub 37 in connection with the drive shaft 35 ', and operation shafts 57, 58 are mounted on a piston 56 of the hydraulic cylinder 55.
The spider 44 is fixed to 58. The lower end of the operating shaft 58 is rotatably supported by the spring hub cover 60. The wheel hub cover 60 is supported by the suction pipe 21 by a support piece 61. The operation shafts 57 and 58 are provided with an oil passage communicating with the hydraulic chamber of the cylinder 55. The oil passage is communicated with a hydraulic source via a hose 62 drawn out of a spring hub cover 60 to the outside. I have. Further, boss oil is supplied to the bearing of the operation shaft 58 of the impeller hub cover 60 via the hose 63. With this configuration, the pressure oil is supplied to and discharged from the hydraulic chamber of the hydraulic cylinder 55 via the hose 62, and the operating shaft is driven to move in the axial direction to control the blade angle. According to this embodiment, the blade angle control mechanism can be made compact. The blade angle control mechanism according to the present embodiment is a mechanism known from Japanese Patent Application Laid-Open No. 58-35294.

[0072]

According to the underground drainage facility of the present invention, the power of the drainage pump can be reduced, the pumping station can be reduced, and the construction and running costs can be reduced.

In addition, a highly reliable underground drainage facility that does not overflow with rivers on the upstream side can be obtained even with a delay in following the inflow water on the upstream side and an upsurge caused by pump stoppage.

[0074]

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of an underground drainage facility showing one embodiment of the present invention.

FIGS. 2A and 2B are explanatory diagrams of a pump operating state according to an embodiment of the present invention, wherein FIG. 2A is a sectional view around a pump well and FIG.

3A and 3B are diagrams illustrating a pump installation position and a starting condition according to the embodiment of the present invention, wherein FIG. 3A is a diagram illustrating a pump operating state, and FIG.

FIG. 4 is a diagram illustrating an operation state of an embodiment of the present invention using a movable blade pump.

FIG. 5 is an enlarged view around a pump station to which the vertical multistage movable blade pump of the present invention is applied.

FIG. 6 is a cross-sectional view of an embodiment of the vertical multi-stage movable blade pump according to the present invention.

FIG. 7 is a sectional view of another embodiment of the vertical axis multistage movable blade pump of the present invention.

FIG. 8 is a longitudinal sectional view of an underground drainage facility showing another embodiment of the present invention.

FIG. 9 is a diagram illustrating an operation state of an embodiment of the present invention in which a small capacity high head pump and a large capacity low head pump are combined.

FIG. 10 is a longitudinal sectional view of an underground drainage facility showing another embodiment of the present invention.

11 is a sectional view of an embodiment in which the actuator of the blade angle control device for the vertical-axis multistage movable blade pump of FIG. 6 is housed in the inner casing of the upper stage movable blade pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inflow shaft 2 Inflow shaft 3 Inflow shaft 4 Inflow water channel 5 Air hole 6 Pump well 7 Drainage pump 7 a, 7 b Movable blade pump 7 c Fixed blade pump 8 Small capacity high head group 9 Large capacity low head pump 10 Discharge pipe 11 Overflow DESCRIPTION OF SYMBOLS 13 Discharge valve 14 Water level gauge 23 Drive 24 Blade angle control device 31 Casing 32 Casing liner 33 Inner casing 35, 35 'Drive shaft 37 Impeller hub 38 Impeller 43 Operating shaft 44 Spider 45 Arm 46 Turnbuckle

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) E03F 5/22 E03B 5/00 F04D 29/22 F04D 29/24

Claims (18)

(57) [Claims] A large-capacity inflow water channel having a small inclination is provided underground at a large depth, and drainage water flows down from the various water distribution channels on the surface of the ground or near the surface of the ground through a vertical shaft into the inflow water channel, and accumulates in the inflow water channel. In a deep underground drainage system configured to drain water from a pumping station provided in a part of the inflow channel to a river, the sea, or the like, the pumping station is located at a position deeper from the ground surface than at the design head of the pump. Install the pump,
This makes it possible to drain the planned amount of water when the inflow channel is a closed channel, and the pump is set to be capable of draining with a small capacity such that the shut-off operation is not performed when the inflow channel is in an open channel. An underground drainage facility characterized by: 2. An inflow channel provided underground for flowing down inflow water, an inflow shaft for guiding water from a river, a culvert, a discharge channel or the like to the inflow channel, and an air hole provided in the middle of the inflow channel. And a pump well arranged at the downstream end of the inflow water channel and a pump provided in the pump well, wherein the inflow water channel is capable of discharging a planned amount of water in a closed water channel, and an open water channel. Underground drainage facility characterized by the installation of a pump that does not operate in the deadline. 3. The pump according to claim 2, wherein the pump provided in the pump well is a movable blade pump, and a drainage standby operation is performed near the minimum blade angle to increase the water level of the pump well or the blade angle of the pump according to the water level rising speed. Underground drainage facility that adjusts and adjusts the amount of drainage. 4. The pump according to claim 2, wherein a plurality of vertical shaft pumps are connected in multiple stages on the same shaft, wherein at least one vertical shaft pump changes the blade angle with respect to the drive shaft. Vertical multi-stage movable blade pump, which is a movable blade pump having a movable blade impeller rotatably supported on a shaft and a blade angle operating mechanism for rotating the movable blade impeller around a support shaft to control a blade angle. An underground drainage facility characterized by: 5. The vertical shaft pump according to claim 4, wherein all of the vertical shaft pumps are movable blade pumps, a drive shaft of each of the movable blade pumps is formed hollow, and the blade angle operating mechanism is inserted through a hollow portion of the drive shaft. An operating shaft, and a link mechanism connected to the operating shaft and the movable blade impeller for converting axial movement of the operating shaft into blade angle rotation of the movable blade impeller. An underground drainage facility comprising a drive shaft and an operation shaft connected to each other. 6. The movable blade pump according to claim 4, wherein at least one of the upper stages of the vertical shaft pump is a movable blade pump, a drive shaft of the movable blade pump is formed in a hollow shape, and the blade angle operating mechanism includes a hollow drive shaft. An operating shaft inserted through the section, and a link mechanism connected to the operating shaft and the movable blade impeller for converting axial movement of the operating shaft into blade angle rotation of the movable blade impeller. An underground drainage facility wherein the drive shafts of the respective stages of the vertical shaft pump are connected and the operation shafts of the upper movable blade pumps are connected. 7. The blade angle operating mechanism according to claim 4, wherein the movable blade pump has two or more stages, wherein the blade angle operating mechanism is configured such that when the upper blade angle becomes the minimum blade angle, the lower blade angle becomes smaller. The underground drainage facility is set so that the angle is slightly larger than the minimum blade angle. 8. The pump according to claim 4, wherein a drainage standby operation is performed near the minimum blade angle of the movable blade pump, and the blade angle of the pump is adjusted according to the rise in the water level of the pump well or the speed of the rise in the water level. Underground drainage facilities characterized by adjusting the amount of drainage. 9. The method according to claim 2, wherein the pump provided in the pump well is a rotation speed control type, and a drainage standby operation is performed at a low rotation speed, and the rotation speed is adjusted according to a rise in the water level of the pump well or the rising speed of the water level. Underground drainage facility characterized by adjusting the amount of drainage. 10. An underground inflow channel provided underground for flowing inflowing water, an inflow shaft for conducting water from a river, a pipe, a drainage channel or the like to the underground inflow channel, and provided in the middle of the underground inflow channel. Air holes, a pump well disposed at the downstream end of the underground inflow water channel, and a pump provided in the pump well, an underground drainage facility including:
A small-capacity high-head pump capable of draining the planned water volume while the underground inflow channel is open and capable of draining the planned water volume in a drainage standby operation, and a large-capacity low-head pump capable of draining the planned water volume in a closed channel. Underground drainage facility characterized by. 11. An underground drainage facility according to any one of claims 1 to 10, wherein the drainage facility is operated by forming an overflow or a siphon without installing a valve on the pump discharge side. 12. The underground drainage facility according to any one of claims 1 to 11, wherein the underwater drainage operation of the pump is performed by detecting a rise in the water level of the upstream inflow channel and the inflow shaft. 13. The underground drainage facility according to claim 1, wherein a drainage standby operation is performed for a predetermined time before the pump is stopped. 14. The method according to claim 1, wherein the height of the overflow of the river, the culvert, and the spillway is determined by the amount of water corresponding to the upsurge when the pump is stopped, and the maximum of the river, sewage, and the spillway. Underground drainage facility characterized by lowering the water level. 15. The method according to claim 1, wherein the height of the overflow in the river, the pipe, and the discharge channel is determined by the time required for the water in the inflow channel immediately below each overflow to start moving after the operation of the pump. The rivers, sewers, spillways,
Underground drainage facilities characterized by lowering the maximum water level of each river, pipe, and spillway. 16. An underground drainage facility according to claim 14 or 15 , wherein the height of the overflow of a river, a sewer, or a spillway is determined to the lower one of claims 14 and 15 . 17. An underground inflow channel provided underground for flowing down inflowing water, an inflow shaft for guiding water from a river, a pipe, a drainage channel or the like to the underground inflow channel, and provided in the middle of the underground inflow channel. Air hole, a pump well disposed at the downstream end of the underground inflow channel, and a pump provided in the pump well, the underground drainage facility, the upstream inflow shaft is compared with the downstream inflow shaft. Underground drainage facilities characterized by being relatively large with respect to inflow. 18. A large-capacity inflow water channel with a small inclination is provided underground at a large depth, and drainage flows down from the various water distribution channels on the surface of the ground or near the surface of the ground through a shaft to the inflow water channel, and accumulates in the inflow water channel. In a drainage pump operating method of a deep underground drainage facility that drains water from a pump station provided in a part of the inflow channel to a river, the sea, or the like, the drainage pump of the pump station causes the inflow channel to be closed. A drain pump operating method, wherein the drain pump is sometimes drained with a planned amount of water, and when the inflow channel is in an open channel state, the drain pump is operated with a small capacity such that the drain pump does not enter the shut-off operation.