JP5155433B2 - Sanding method - Google Patents

Description

  The present invention relates to a sand pumping method in which sand (sediment sand) precipitated on a bottom surface of a sand basin of a sewage treatment facility is collected in a sand collecting pit by jet water, and the sand is sucked and transferred by a sand lifting device.

  Conventionally, a storm water settling basin of a storm water pumping station in a sewage treatment facility has been provided with a sand raising device comprising a jet pump for transferring sand deposited on the bottom surface of the storm water settling basin to a predetermined location. The suction port of the jet pump in this sand pumping device is provided so as to be located above the sand collecting pit provided at the lowest position on the bottom surface of the rainwater settling basin. Therefore, when the jet pump is driven, the sand in the sand collection pit is sucked from the suction port and transferred to a predetermined place via the pipe.

  Further, since the sand pumping apparatus using the jet pump uses high-pressure water as a driving source, the power cost is high, and there is a sand pumping apparatus using a spiral blade type sand pump that is inexpensive in power cost.

In the sand pumping apparatus using this sand pump, the suction port of the sand pump is located near the bottom surface of the sand collecting pit. Therefore, when the sand pump is driven, the sand in the sand collecting pit is sucked from the suction port and transferred to a predetermined place through the pipe.

  When the sand in the sand collection pit is sucked by the above sand lifting device and transferred to a predetermined location, the sand settling at the bottom of the sand settling basin is injected from the sand collecting nozzle when using either a jet pump or a sand lifting pump. It is necessary to flow down with water and collect sand in a sand collecting pit (there is no prior art document).

If the water level in the settling basin at the start of sand collection using the water jetted from the sand collecting nozzle is at a high level equal to the top of the continuous section provided between the settling pond and the pump well, not only uneconomical because the amount of transfer is increased, so to move the grit overcoming the water pressure must be condensed sand, is ejected at high pressure water from Atsumarisuna nozzle, converging by the high-pressure sand ( Hereinafter, this is referred to as “high pressure sand collection”) . High 圧集 sand, not to produce the high pressure only takes running cost, becomes larger construction equipment. Further, when the high 圧集 sand, suspended soaring part of the sand in water, also thereafter for depositing settled again collecting sand efficiency has the drawback to decrease. Furthermore, the generation of sewage mist due to high-pressure water is also a big problem from a hygienic point of view.

  Moreover, in the conventional sand raising device, even though sand is present in the sand collecting pit, even if the jet pump or the sand raising pump starts driving, the sand cannot be sufficiently sucked, Therefore, there is a disadvantage that the sand cannot be sufficiently moved.

  This is because when the jet pump or the sand pump starts driving, the suction port is blocked by the sand that has accumulated in the sand collection pit, and neither water nor sand can be sucked.

Accordingly, the present invention has been made to solve the above-described drawbacks, and sand collection is performed by jetting pressure water from a sand collection nozzle at a low pressure , that is, a low-pressure sand collection. It aims to provide a method.

In order to achieve the above-mentioned object , the present invention collects sand deposited on the bottom surface of a sand basin of a sewage treatment facility into a sand collecting pit with jet water, and sucks and transfers the sand by a sand lifting device. In the method, when the water level of the sand basin reaches the bottom level of the central trough, pressure water injection from a sand collecting nozzle for flowing down the sand settled on the bottom surface of the sand basin is started, and the bottom surface of the sand basin Are divided into a plurality of regions in the longitudinal direction of the central trough, and the sand collecting nozzles of each region are grouped into a sand collecting nozzle group, and the pressure water jet from the sand collecting nozzle is jetted to the central trough And then spraying from the sand collecting nozzle of the central trough and spraying from the sand collecting nozzle group of each region alternately for each region. to (claim 2).

  Further, the present invention is characterized in that, in the sanding method, the injection from the sand collecting nozzle group in each region is performed in order from the region close to the sand collecting pit (claim 2).

  Furthermore, the present invention is characterized in that, in the above sand pumping method, after the injection from the sand collecting nozzle group in all regions, the injection from the sand collecting nozzle of the horizontal trough connected to the sand collecting pit is performed ( Claim 3).

According to lifting the sand method of the present invention, and Atsumarisuna the collecting sand pit sand of sand basin by pressure water injection from Atsumarisuna nozzle, in Agesuna method of transferring by suction the sand by Agesuna apparatus, low pressure Sand collection can be realized more efficiently than before .

According to invention of Claim 3 , 4 , sand collection efficiency further improves.

BRIEF DESCRIPTION OF THE DRAWINGS The sand basin to which the sand lifting method of this invention is applied is shown, Comprising: (a) is the longitudinal cross-sectional view, (b) is a partial top view of (a). FIG. 2 is a cross-sectional view taken along the line II in FIG. It is a flowchart which shows control operation. It is a schematic sectional drawing of a sand basin and a pump well. It is a top view of the left side part of FIG.

As shown in FIG. 4, in the sand basin 1, as shown in FIG. 4, rainwater flows from one side (left side in FIG. 4) of the sand basin 1, and the rainwater settled and separated from the sand is the other side of the sand basin 1. It is formed so as to flow out to the pump well 30 connected to the sand basin 1 from the side . To further illustrate with reference to FIG 1 (b), when the paper upper side shown in FIG. 1 (b) and rainwater inflow, rainwater settling sand is to flow out from the plane lower side shown in FIG. 1 (b) It becomes.

The form of the bottom face 1a of the sand basin 1 is to collect sand (not shown) on the bottom face 1a in a sand collecting pit 2 having a flat bottom that is lower than the bottom face 1a provided at a substantially central position of the bottom face 1a. It is formed so that it can be. That is, as shown in FIG. 1 (a), the bottom surface 1a is inclined so that the center line in the rainwater inflow direction is lowest, and as shown in FIG. It is inclined so that the part of the is the lowest. Therefore, as the sand on the bottom surface 1a, when to discharge the water from the collection sand nozzle described below on the bottom surface 1a (40, 41, 42 in FIG. 5), indicated by the arrows in FIG. 1 (b), They are gathered together in the sand collecting pit 2 via a central trough 1b and a lateral trough 2b described later .

The sand collecting pit 2 is provided with a sand pump 10 constituting a sand pump. The sand pump 10 is a known submersible pump having spiral blades, and a pump that has been used as a submersible sludge pump in a sewage treatment facility can be used. The Agesuna pump 10, the downward suction port 11, i.e., toward the suction port 11 to the bottom surface 2a of Atsumarisuna pit 2, are provided in the settling basin 1 through the discharge pipe 12 and the support 13.

Between the suction port 11 of the sand pump 10 and the bottom surface 2a of the sand collection pit 2, the disturbance nozzles 20a and 20b flow into the sand collection pit 2 from the center trough 1b described later on the opposite sides of the suction port 11. (See FIG. 1B). Further, the disturbance nozzles 20 a and 20 b are arranged so that the injection directions thereof are substantially opposed with the suction port 11 of the sand pump 10 as the center. Accordingly, since the jetting directions give vectors opposite to each other at positions opposite to each other on the circle centered on the center of the suction port 11, sand precipitated near the suction port by jetting from the disturbance nozzles 20a and 20b is good. It is disturbed and efficiently sucked into the suction port.

As shown in FIG. 4, the pump well 30 connected to the sand basin 1 is provided with a drain pump 31 and a stagnant water pump 32 separately. The sewage such as rainwater pumped up by the staying water pump 32 ejects pressure water so that the sand accumulated on the bottom surface 1a of the sand basin 1 flows out toward the sand collecting pit 2 via a switching valve (not shown). It is supplied to the sand collecting nozzles 40, 41, 42 to be caused.
Although not shown, they are provided in the sand pump 10, the pump (not shown) for supplying pressure water to the disturbance nozzles 20a and 20b, and the supply pipes 21a and 21b for supplying pressure water to the disturbance nozzles 20a and 20b, respectively. The valves and the like are configured to be driven and controlled by a controller (not shown) formed around a programmable controller that controls the sand basin 1 in an integrated manner.

  Based on FIG. 3, the procedure of sand collection and sand lifting will be described in detail.

[Stoppage of sewage inflow and drainage of stagnant water]
First, the gate 50 in FIG. 4 is closed to stop the inflow of sewage into the sand basin 1 (step 1. Hereinafter, step is referred to as “S”). Next, the staying water pump 32 drains the wastewater to a sewage settling basin, an inflow trough, etc. (not shown) through the switching valve (S2).

Since the settling basin 1 is connected to the pump well 30 via the continuous portion 60, if it is described with reference to FIG. 4, it is drained by the staying water pump 32 to the level La which is the top level of the continuous portion 60. However, the accumulated water below the level La of the sand basin 1 is not drained. In other words, in the present invention, it is to be drained accumulated water in the pump well 30 and the settling basin 1 to a level La by stagnant water pump 32 (S2 to S4).

[Disturbance and sanding]
As described above, when the inflow of rainwater into the sand basin 1 is stopped (S1) and the process of draining the accumulated water in the sand basin 1 to the level La (S2 to S4) is completed , the supply pipes 21a and 21b are provided. The valves (not shown) are respectively opened to start the injection of pressure water from the disturbance nozzles 20a and 20b, and the counting of the first timer T1 (not shown) is started (S5). After the time-up of the first timer T1, that is, after the disturbance is performed for a certain time , the driving of the sand pump 10 is started and the count of the second timer T2 is started (S6, S7).

Disturbance nozzles 20a, the pressurized water from 20b is ejected, because the injection direction which gives a vector in the opposite directions to each other in mutually opposite positions of a circle centered on the center of the suction port 11, near the suction port 11 of its The sand accumulated in the sand is disturbed, and the disturbance gradually spreads throughout the sand collecting pit 2. Therefore, the sand is efficiently sucked from the suction port 11 by being accompanied by water and transferred to a predetermined place via the discharge pipe 12.

After the second timer T2 expires, for example, one minute after the second timer T2 starts, the valves of the disturbance nozzles 20a and 20b are closed (S9) . That is, the injection pressure water Ru is stopped. Even if the disturbance nozzles 20a and 20b are closed and the water ejected from the disturbance nozzles 20a and 20b disappears, the sand is turned into the water to be sucked because the vicinity of the suction port 11 is fluidized by driving the sand pump 10. Accompanied with effective discharge.

Thus, the injection of the pressure water from the disturbance nozzles 20a and 20b only needs to destroy and disturb the accumulated sand in the vicinity of the suction port 11 of the sand pump 10, so that the disturbance time is the operation of the sand pump 10. A short time from before the start of is enough. Therefore, it is not necessary to always continue the injection of the pressure water from the disturbance nozzles 20a and 20b during the operation of the sand pump 10, so that the operation cost can be reduced.

When a water level gauge ( not shown) provided in the sand collection pit 2 detects a predetermined water level by discharging sand and water from the sand collection pit 2 by the sand collection pump 10 (Y in S10) , The driving is stopped (S11).

[Sand collection]
Next, the valves of the sand collecting nozzles 40, 41 and 42 are sequentially opened to collect sand (S12) . More specifically, a pressure fluid is jetted from the sand collecting nozzle 40 provided at the upper end of the central trough 1b in the extending direction of the central trough 1b to guide the sand sediment deposited on the central trough 1b into the sand collecting pit 2, The trough 1b is washed. The central trough 1b is the final and main trough connected to the sand collecting pit 2, and is therefore intended to prevent burial due to sedimentation when rainwater is received.

And, thereafter, alternately collecting sand nozzle 41 ..., the Atsumarisuna nozzles 40, 40 of the central trough 1b which is provided in the precipitation sand pond bottom disposed between a plurality of small troughs 1c perpendicular to the central trough 1b To erupt. The sand collecting nozzles 41, 41... Eject the pressure fluid in a direction orthogonal to the extending direction of the central trough 1b. Sand collection to the sand collection pit 2 is performed through the small trough 1c and the central trough 1b by alternately ejecting the sand collection nozzles 41, 41.

  When the area of the bottom surface 1a of the sand basin is large, the bottom surface 1a is appropriately divided into a plurality of regions, and the plurality of sand collecting nozzles 41, 41. The ejection of pressure water from each sand collecting nozzle group is performed in order from the side closer to the sand collecting pit 2.

[Repeated sand collection and pumping]
Finally, the sand accumulated in the pond width direction of the sand basin near the sand collection pit 2 is collected in the sand collection pit 2 by the sand collection nozzles 42 and 42 provided in the horizontal trough 2 b connected to the sand collection pit 2. When the water level meter in the sand collecting pit 2 detects a predetermined upper limit water level by sequentially opening the valves of the sand collecting nozzles 40, 41, 42, the driving of the sand pump 10 is resumed, and as the driving resumes, When the water level gauge detects a predetermined lower limit water level, the sand pump 10 is stopped. After completion ejection from collecting sand nozzles 42 and 42, when the water level indicator detects a predetermined lower limit level, Agesuna pump 10 is stopped driving, the state continues. Thereby, the sanding by the sand pump 10 is completed.
That is, Agesuna pump 10, while at the time Agesuna completion or from Atsumarisuna start, depending on the fluctuations in the water level in the Atsumarisuna pit 2 resumes driving upper limit water level detection of the water level gauge, lower limit level It is controlled to stop the drive upon detection.

  In the above-described example, a known submersible pump having a spiral blade is shown as the sand pump 10, but it is needless to say that it may be a jet pump. Moreover, although the number of nozzles in the sand collecting pit 2 is two, it may be three or more.

  In the above example, the disturbance nozzles 20a and 20b are provided with two timers T1 and T2 and driven before and after the sand pump 10 is driven. However, the timer is one and the sand pump 10 is driven. You may make it drive for the predetermined time before a start. However, as described above, when the disturbance nozzles 20a and 20b are driven before and after the sand pump 10 is driven, due to the synergistic effect of fluidization by the sand pump 10 and fluidization by the disturbance nozzles 20a and 20b. , Can further enhance the disturbing effect.

In the state where the accumulated water below the level La of the sedimentation basin 1 is not drained by the drainage by the accumulated water pump 32, the amount of pumped water by the sandpump increases, which is not economical, and the sand pressure is overcome by overcoming the water pressure. It is necessary to carry out sand collection by moving the sand and pressure water from the sand collection nozzles 40, 41, 42 is ejected at a high pressure, and high pressure sand collection is required. Not only does it cost to run, but the number of components increases, and when sand collection is performed at high pressure, part of the sand rises and floats in the water, and then sinks and accumulates again, reducing sand collection efficiency. As described above, there is a drawback, and the generation of sewage mist due to high-pressure water is also a serious problem in terms of hygiene.
Therefore, in order to solve these problems, in the present invention, sand collection and pumping in a dry (drainage) state, and sand collection in which pressure water from a sand collection nozzle is ejected at a low pressure are performed.

As described above, after the pressure water is jetted from the disturbance nozzles 20a and 20b to the sand settled near the suction port 11 of the sand pump 10 of the present invention and disturbed for a certain time, the sand pump 10 is driven to level. Drain the stagnant water below La. At this time, it is preferable to use water pumped up by the staying water pump 32 for the disturbance nozzles 20a and 20b. And if the water of a sedimentation basin is drained to the predetermined water level in the sand collection pit 2 by the sand pump 10, the drive of the sand pump 10 will be stopped. Here, the predetermined water level is a water level that realizes a dry (drainage) state in the sand basin 1, and is set within a range where high load or high pressure sand collection of the sand pump 10 is not required. In the invention, the bottom level of the central trough 1b (between the upper end and the lower end of the bottom) is set to a predetermined water level.
As described above, when the drainage state is reached, sand collection, that is, pressure water ejection from the sand collection nozzle is performed, and the suspension of the sand pump 10 due to the water level of the settling basin having reached a predetermined water level and collection. When the water level of the sedimentation basin rises to the upper limit water level due to sand, the driving of the sand pump is resumed, and when the water level falls to the lower limit water level due to the resumption of driving, the driving of the sand pump 10 is stopped.

1 rainwater settling basin (sedimentation basin)
DESCRIPTION OF SYMBOLS 1a Bottom face of rainwater settling basin 1b Central trough 1c Small trough 1d Horizontal trough 2 Sand collection pit 2a Bottom of sand collection pit 10 Sand pump 11 Suction port 12 Discharge pipe 20a, 20b Disturbing nozzle 21a, 21b Supply pipe 40, 41, 42 Sand collecting nozzle

Claims (3)

In the sand-carrying method, sand collected on the bottom surface of the sand basin of the sewage treatment facility is collected in a sand collecting pit by jet water, and the sand is sucked and transferred by a sand-carrying device.
When the water level of the sand basin has become the bottom level of the central trough, and starting pressure water jet from collecting sand nozzle for flow down the sand precipitated to the bottom surface of the sand basin,
While dividing the bottom surface of the sand basin into a plurality of regions in the longitudinal direction of the central trough, the sand collecting nozzles of each region are set as a unit of sand collecting nozzles,
After the pressure water jet from the sand collecting nozzle is jetted to the central trough, the jet is sprayed to the bottom surface of the sand basin, the central trough jet from the sand collecting nozzle, The spraying from the sand collecting nozzle group is performed alternately for each region.
A sanding method characterized by that. 2. The sanding method according to claim 1 , wherein the injection from the sand collecting nozzle group in each region is sequentially performed from a region close to the sand collecting pit. 3. The sand pumping method according to claim 1, wherein after the injection from the sand collecting nozzle group in all areas, the injection from the sand collecting nozzle of the lateral trough connected to the sand collecting pit is performed. How to sand up.

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