JP5342101B2 - Pneumatic transport system for slurry-like soil - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a pneumatic transportation system for slurry-like earth and sand, in which slurry-like earth and sand containing water is pumped by air pressure through a transportation pipe.

  In the present invention, the slurry-like earth and sand refers to various slurry-like earth and sand that contain water and have viscosity and can flow in the transport pipe. For example, dredged sand and mud (for example, sludge) generated at the bottom of the water bottom. Of course, various treatment agents (for example, solidifying agents) are added to them and mixed to form a slurry.

  Conventionally, a sediment supply device capable of forcibly supplying slurry-like earth and sand into a transport pipe, and an upstream end of the transport pipe with compressed air for pressure-feeding the slurry-like earth and sand supplied into the transport pipe by the earth and sand supply device Alternatively, a pneumatic transportation system for slurry-like sediment using a sediment transporter equipped with a compressed air mixing device capable of being mixed in the slurry-like sediment in the vicinity thereof is already known.

  In this system, when compressed air is continuously mixed into the slurry-like soil inside the transport pipe, the slurry-like sand that flows in the slag shape at the bottom of the transport pipe (hereinafter referred to simply as slag flow or slag-like liquid phase part). ) Undulates and repeats pressure fluctuations, part of the slag flow reaches the ceiling surface of the transport pipe and forms a plug, and the plug-like liquid phase and the gas phase composed of compressed air are transported. It is known to produce a so-called plug flow that flows alternately in the longitudinal direction of the tube. By generating this plug flow, the apparent frictional force between the slurry-like soil and the inner surface of the transport pipe can be reduced, and the slurry-like soil can be efficiently mass transported with relatively small energy.

  By the way, when carrying out long-distance transportation of earth and sand using the pneumatic transportation system, when the transportation pipe itself is extended for a long time without providing a relay facility, for example, as illustrated in FIG. 8, a plug generated in the transportation pipe As the flow approaches the downstream end of the transport pipe by repeatedly collapsing the plug-like liquid phase due to pressure fluctuations in the gas phase and re-forming the plug-like liquid phase due to coalescence after the collapse, As the liquid phase part gradually grows and enlarges, the pressure in each gas phase part increases to pump this, and the back pressure applied to the earth and sand transport machine increases. For this reason, it is necessary to increase the original pressure of the earth and sand transporter (that is, the pipe internal pressure at the upstream end of the transport pipe) in response to the increase in the back pressure. There is a problem that durability of each part of the earth and sand transport machine and the transport pipe is lowered.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a new and useful pneumatic pneumatic transportation system for slurry-like earth and sand that can solve the above-described conventional problems at once with a simple structure. And

In order to achieve the above object, the invention according to claim 1 is a pneumatic transport system for slurry-like earth and sand that is viscous and contains water-containing slurry-like earth and sand via a transport pipe, wherein the slurry-like earth and sand is Sediment supply device that can be forcibly supplied into the transport pipe, and compressed air for pumping the slurry-like sediment supplied to the transport pipe by the sediment supply equipment to the downstream side of the transport pipe or the vicinity thereof In the transport pipe, the plug-like liquid phase part made of slurry-like sand and the gas phase part made of compressed air are transported along the length of the transport pipe. A plug flow that flows alternately in the hand direction and flows in the downstream direction is generated. In the middle of the transport pipe, a check valve for preventing a back flow and an expansion that the downstream side of the check valve directly faces the check valve A room In both cases, the upper end of the plate-like valve body is pivotally connected to the upper wall of the expansion chamber so that the plate-like valve body can be opened and closed between the open position and the closed position. An auxiliary compressed air input portion having an injection port for discharging auxiliary compressed air toward the downstream side of the transport pipe is provided so that the injection port is located immediately below the opening / closing operation region of the plate-shaped valve body , The bottom surface is lowered by one step from the bottom surface of the transport pipe connected immediately upstream thereof, and the auxiliary compressed air input portion is provided at the step portion so that the injection port is directed downstream of the transport pipe. It shall be the feature.

Furthermore, in addition to the above-described configuration of the invention of claim 1, the invention of claim 2 includes a plurality of the injection holes, wherein the auxiliary compressed air input portions include the nozzle holes arranged at intervals in the flow direction of the slurry-like earth and sand. It has a nozzle hole.

  As described above, according to the present invention, a check valve for preventing backflow and an expansion chamber directly facing the valve body downstream side of the check valve are provided in the middle of the transport pipe, and the upper end of the plate-like valve body is provided. The upper part of the expansion chamber is pivotally connected to the upper wall of the expansion chamber so that the plate-like valve body can swing between the open position and the closed position, and the lower part of the peripheral wall of the expansion chamber faces the downstream side of the transport pipe Since the auxiliary compressed air input portion having the nozzle hole for jetting the auxiliary compressed air is provided so that the nozzle hole is located immediately below the opening / closing operation region of the plate-like valve body, it tends to enlarge as it approaches the downstream end in the transport pipe. The collapse of the plug-like liquid phase part is promoted, and a smaller plug-like liquid phase part can be efficiently regenerated. As a result, even if the transport pipe is extended for a long distance transport, the individual plug-like liquid phase part in the plug flow in the transport pipe can be made as small as possible near the downstream end of the transport pipe. Since the applied back pressure is reduced and the original pressure of the earth and sand transport machine can be reduced, the equipment cost and the operating cost can be reduced, and the durability of each part of the apparatus and the transport pipe can be improved. Moreover, expensive relay equipment is not required, and long-distance transport of earth and sand can be efficiently performed with minimum energy. Furthermore, aerobic microorganisms in the slurry-like soil can be activated by the aeration effect by introducing auxiliary compressed air in the middle of the transport pipe, which can contribute to soil purification.

  In addition, the plate-shaped valve body of the check valve faces the expansion chamber, and the upper end of the plate-shaped valve body is pivotally connected to the upper wall of the expansion chamber so that it can be opened and closed. A check valve can be easily installed.

Further the bottom surface of the bulging脹室is lowered one step than the bottom surface of the transport tube connecting to the immediately upstream, to the stepped portion, is provided with the auxiliary compressed air input unit of the nozzle hole is directed to the transport tube downstream expansion Slurry earth and sand (slag flow) flowing over the bottom of the chamber can be sufficiently stirred with auxiliary compressed air, and the slurry and earth can be effectively prevented from settling and staying at the bottom of the expansion chamber.

According to the invention of claim 2 in particular, the auxiliary compressed air input portion has a plurality of injection holes including the injection holes arranged at intervals in the flow direction of the slurry-like earth and sand. Auxiliary compressed air can be introduced from two different locations in the transport pipe directly under the check valve so that the compressed air input part can be mixed efficiently with the slurry-like soil, thereby promoting the collapse of the plug-like liquid phase part. Thus, it can be efficiently regenerated into a smaller plug-like liquid phase part.

  Embodiments of the present invention will be specifically described below based on the embodiments of the present invention illustrated in the accompanying drawings.

  1 to 7 show an embodiment of the present invention, FIG. 1 is an overall longitudinal sectional view of a pneumatic transportation system, and FIG. 2 is a partially broken view showing a sediment transporter. FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. 2, and FIG. 4 is a longitudinal sectional view of plug flow regeneration promoting means (four parts in FIG. 1). 5 is a cross-sectional view taken along line 5-5 of FIG. 4, and FIG. 6 is a vertical cross-sectional view schematically showing the flow state of the plug flow in the plug flow regeneration promoting means (before and after the check valve). It is a figure, (A) shows the fluid state of a liquid phase part, and (B) shows the fluid state of a gas phase part. FIG. 7 is a longitudinal sectional view schematically showing the flow state of the plug flow over the entire transport pipe in the embodiment.

  First, in FIG. 1 to FIG. 3, the pneumatic transportation system for dredged sand is a barge that can store dredged sand 20 as slurry-like sand containing water generated in other dredging work sites and transport it over the water. A ship B, a mud working ship A to which the barge B can be placed, and a transport pipe P extending from the mud work ship A to a landfill U as a sediment disposal site, are connected via the transport pipe P. Then, the dredged sand 20 is transported in large quantities from the mud working boat A to the landfill U using air pressure. The transport pipe P is supported in a floating state by the float f in the water portion.

  The pumping work boat A includes a backhoe 1 that scrapes dredged sand 20 stored in the barge B, a hopper 2 into which dredged sand 20 scraped by the backhoe 1 is placed, and a lower portion of the hopper 2. A suction unit that is provided in series and is provided with an earth and sand supply device SS that can push and supply the dredged soil 20 in the hopper 2 into the transport pipe P by a fixed amount, and is provided at the upper part of the casing H of the device SS and opens upward. The mouth Hi communicates directly with the bottom of the hopper 2. A discharge port Ho is opened downward at the bottom of the casing H, and the upstream end Pu of the transport pipe P is connected to the discharge port Ho via a sediment discharge pipe 4 whose middle part is bent sideways. .

  The earth and sand supply device SS can be appropriately selected regardless of the structure type as long as the earth and sand 20 in the hopper 2 can be pushed and fed into the transport pipe P by a fixed amount. A rotary earth and sand supply device in which a cylindrical rotor R that is rotationally driven by a motor M is housed in a cylindrical rotor case portion formed integrally with H is used. A plurality of transfer chambers Ra are recessed at equal intervals in the circumferential direction on the outer peripheral portion of the rotor R, and each transfer chamber Ra is periodically connected to the suction port Hi of the casing H as the rotor R rotates. The dredged sand 20 is received from the bottom of the hopper 2 to the bottom of the hopper 2 by a certain amount and is forcibly transferred to the lower discharge port side to perform the sand supply operation.

  In the earth and sand discharge pipe 4, compressed air can be continuously mixed into the earth and sand with compressed air for pumping the earth and sand 20 supplied into the transport pipe P by the earth and sand supply device SS to the downstream side. The device SA is connected. This compressed air mixing device SA passes through a compressor C installed at an appropriate location near the transport pipe P (on the mud working vessel A in the illustrated example), and an air pipe 6 with an on-off valve 6v on the discharge side of the compressor C. The nozzle pipe 7 communicates with the earth and sand discharge pipe 4 through the pipe wall in a liquid-tight manner and opens into the pipe, and the nozzles N and N ′ are directed in the transport pipe P. doing.

  In the illustrated example, two nozzle holes N and N ′ are provided at the front and rear of the nozzle pipe 7, and one (lower) nozzle hole N ′ extends downstream and faces the upstream end of the transport pipe P. . Compressed air can be supplied from two different locations in the sediment discharge pipe 4 from the nozzle holes N and N ′ of the nozzle pipe 7.

  Thus, the earth and sand supply device SS and the compressed air mixing device SA constitute the earth and sand transporter S that supplies the dredged sand 20 and the compressed air to the upstream end of the transport pipe P. In such a pneumatic transportation system using the earth and sand transporter S, when the motor M and the compressor C are operated in a state in which dredged earth and sand are sufficiently put into the hopper 2, the earth and sand supply device SS is provided at the upstream end of the transportation pipe P. At the same time, a fixed amount of dredged soil is supplied from the nozzle pipe 7 and compressed air is ejected vigorously from the nozzle pipe 7 and mixed into the dredged sand. At this time, the transport pipe P is composed of dredged sand as shown in FIG. The plug-like liquid phase part 8 and the gas phase part 9 made of compressed air are alternately arranged in the longitudinal direction of the transport pipe and flow in the downstream direction (this flow is the gas phase part 9 before and after sandwiching the plug-like liquid phase part 8, 9 a plug flow PL is generated in which the mutual differential pressure overcomes the flow resistance including the frictional resistance acting on the plug-like liquid phase portion 8 from the transport pipe P, which is generated between the dredged sand and the inner surface of the transport pipe P. Reduce the apparent frictional force between Since, the efficient mass transport permit dredged material with a relatively small energy. In the gas phase portion 9 as well, a slag-like liquid phase portion flows slightly to the bottom of the transport pipe P.

  By the way, when the transport pipe P is elongated as in this embodiment, the plug-like liquid phase portion 8 of the plug flow PL generated in the transport pipe P as described above gradually grows as it approaches the downstream end of the transport pipe. , Enlarged (FIG. 8), the pressure of each gas phase portion 9 increases to pump this, and the back pressure applied to the earth and sand transport machine S (that is, the pressure inside the pipe at the upstream end of the transport pipe P) increases. This causes various problems as described above. Therefore, in this embodiment, the plug-like liquid phase portion 8 that is to be enlarged as it approaches the downstream end of the transport pipe P is collapsed, and the plug flow regeneration is performed to efficiently regenerate the smaller plug-like liquid phase portion 8. At least one set of means X is provided. Next, an example will be described with reference to FIGS.

  That is, the plug flow regeneration means X feeds auxiliary compressed air into a check valve V for preventing a reverse flow provided in the middle of the transport pipe P and the transport pipe P immediately downstream of each check valve V. An auxiliary compressed air nozzle tube 15 serving as an auxiliary compressed air charging unit is included. The nozzle pipe 15 is connected to the discharge side of the compressor C ′ installed at an appropriate position near the transport pipe P (on the mud working vessel A in the illustrated example) via an air pipe 6 ′ with an on-off valve 6 v ′. The check valve V is disposed at a considerable distance from the upstream end of the transport pipe P to the downstream side, and the enlargement of the plug-like liquid phase portion 8 greatly affects the back pressure to the sediment transporter S. When the transport pipe P is long, a plurality of check valves V are arranged at intervals in the flow direction of dredged sand. Also, the check valve V can be disposed at the front side of the upstream pipe portion of the transport pipe P where the influence of the back pressure on the earth and sand transporter S is large.

  An expansion chamber 10 having a flow passage cross-sectional area larger than that of the transport pipe P immediately downstream of the check valve V directly faces the transport pipe P on the downstream side of the valve body 13 of the check valve V. The expansion chamber 10 is formed by integrally installing an expansion chamber forming tube Pa in the middle of the transport tube P. The upstream half of the expansion chamber forming pipe Pa is formed in a rectangular cross section having a large flow path cross-sectional area, and the downstream half is gradually narrowed toward the downstream side and smoothly into the downstream transport pipe P. Connected to.

  The downstream end of the upstream portion of the transport pipe P from the expansion chamber 10 is cut by a diagonally upward plane, the cut surface becomes the valve seat surface 11 of the check valve V, and the cut portion opening becomes the valve hole 12. . The check valve V is composed of a leaf valve having a rectangular flat valve element 13 facing the expansion chamber 10. A reinforcing rib and a weight are provided on the outer surface of the valve element 13 opposite to the valve seat surface 11. Reinforcing piece 16 also serving as is fixed.

  The upper end of the valve body 13 is connected to the upper part of the expansion chamber forming pipe Pa via a pivot shaft 14, and the valve body 13 abuts against the valve seat surface 12 around the axis of the pivot shaft 14. It can be opened and closed between a closed position where the middle of the transport pipe P is blocked and an open position where the middle of the transport pipe P is separated from the valve seat surface 12.

  Due to the arrangement of the valve body 13 as described above, in particular, the position of the pivot shaft 14 and the upward inclination of the valve seat surface 11, the valve body 13 in the closed position is subjected to a gentle valve closing force by its own weight. The body 13 is normally held in a closed state. Further, when a differential pressure toward the downstream side is generated before and after the valve body 13, the valve body 13 swings smoothly in response to the differential pressure. On the other hand, when a differential pressure toward the upstream side of the valve body 13 is generated, the valve body 13 immediately swings in the closing direction and is held at the closed position.

  The pivot shaft 14 has an intermediate portion fixed to the upper end portion of the valve body 13, and both end portions penetrating and supported on both side walls of the expansion chamber forming pipe Pa in a liquid-tight and relatively rotatable manner. A weight W is integrally connected to the outer end of the pivot shaft 14, so that the valve body 13 can be lightened according to the differential pressure without being affected by its own weight at any opening degree. Can swing open and close.

  The lower part of the peripheral wall of the expansion chamber 10, that is, the bottom surface, is one step lower than the bottom surface of the transport pipe P connected immediately upstream thereof, and auxiliary compressed air is jetted to the downstream side facing the downstream side of the transport pipe P. The nozzle tube 15 to be obtained is liquid-tightly penetrated and supported. In the illustrated example, two nozzle holes n and n ′ are provided at the front and rear in the illustrated example, and one (upper) nozzle hole n is a valve body of the check valve V as shown in FIGS. 4 to 6. Since the other (lower) nozzle hole n 'is extended downstream, the auxiliary compressed air is supplied from two different locations of the expansion chamber 10 from the nozzle pipe 15, respectively. Can be thrown in. Further, the ceiling surface of the expansion chamber 10 is one step higher than the ceiling surface of the transport pipe P continuous immediately upstream thereof, and the pivot shaft 14 of the valve body 13 extends across the expansion chamber 10 along the step portion. .

  Next, the operation of the embodiment will be described. The dredged sand 20 including water collected at a dredging work site (not shown) is stored in the barge ship B and transported over the water to a water area near the landfill U which is the final disposal site. In the water area, a mud working boat A stands by, and a transport pipe P is installed in advance from the working boat A to the landfill U.

  Therefore, after laying the barge B on the pumping work ship A, the stored soil 20 in the barge B is scraped out and put into the hopper 2 by the backhoe 1, and when the input amount exceeds the specified amount, the motor M and the compressor Start operation of C. Thereby, the dredged sand 20 in the hopper 2 is supplied to the transport pipe P by the sediment supply device SS through the sediment discharge pipe 4 in a fixed amount, and at the same time, compressed air from the compressor C passes through the air pipe 6 and the sediment discharge pipe 4 to the transport pipe. It is mixed in dredged sand 20 near the upstream end of P. At this time, in the transport pipe P, as shown in FIG. 7, the plug-like liquid phase portion 8 made of dredged sand and the gas phase portion 9 made of compressed air flow alternately downstream in the longitudinal direction of the transport pipe. A plug flow PL is generated. On the other hand, the compressed air from the compressor C ′ is injected from the nozzle pipe 15 to the downstream side (expansion chamber 10) of each check valve V through the air pipe 6 ′.

  Then, when the transport pipe P is extended as shown in the illustrated example, if there is no plug flow regeneration means X, the plug flow PL generated in the transport pipe P as shown in FIG. By repeating the collapse of the portion 8 and the re-formation by coalescence after the collapse, the plug-like liquid phase portion 8 tends to gradually grow and enlarge as it approaches the downstream end of the transport pipe. However, in this embodiment, auxiliary compressed air is introduced into the plug flow regeneration means X, that is, the check valve V for preventing the reverse flow, and the transfer pipe P immediately downstream of the check valve V in the middle of the transport pipe P. Since the auxiliary compressed air charging portion (nozzle tube 15) is provided, the plug-like liquid phase portion 8 to be enlarged can be efficiently regenerated into a smaller plug-like liquid phase portion 8 as shown in FIG. is there.

  That is, when the plug-like liquid phase portion 8 that is being enlarged reaches the check valve V, the plug-like liquid phase portion 8 opens while opening the valve-like liquid phase portion 8, and immediately after the passage, flows into the expansion chamber 10 having a large flow path cross-sectional area. Collapse of the plug-like liquid phase portion 8 begins. When a part of the plug-like liquid phase portion 8 passes through the check valve V, the space between the plug-like liquid phase portion 8 and the check valve V immediately after passing is relatively small. The pressure in the pipe immediately downstream of the check valve V is suddenly increased by the auxiliary compressed air introduced into the expansion chamber 10 to temporarily close the check valve V, and the increased pressure in the pipe causes the slag flow to vigorously flow downstream. Extrude (see FIG. 6A). In addition, since the back pressure at this time is received by the check valve V, it does not spill over to the sediment transport machine S on the upstream side. Thereafter, when the pipe pressure immediately downstream of the check valve V decreases, the check valve V opens again, and a part of the remaining part of the plug-like liquid phase portion 8 passes through the check valve V. The same action as described above is performed.

  By repeating the opening / closing operation of the check valve V and the slag flow pushing action by adding auxiliary compressed air, the slag-like liquid phase portion after passing through the check valve is sufficiently agitated, resulting in a turbulent state and pressure fluctuation. While moving repeatedly in the transport pipe P, the plug-like liquid phase portion 8 is regenerated again in the process. Moreover, since the regenerated plug-like liquid phase portion 8 is smaller than the plug-like liquid phase portion 8 immediately before passing through the check valve V, the differential pressure between the front and rear gas phase portions 9 and 9 is relatively small. Also flows to the downstream side without difficulty (FIG. 7). Even if the regenerated plug-like liquid phase portion 8 grows and enlarges again on the downstream side, the plug-like liquid phase portion can be obtained by the same action as described above by the plug flow regenerating means X disposed on the downstream side. 8 is played back.

  Further, as shown in FIG. 6B, when the gas phase portion 9 in the plug flow PL reaches the check valve V, the pressure change before and after the check valve is relatively small. The gas phase section 9 is moved, that is, the check valve is passed while the valve is kept open.

  Thus, in the middle of the transport pipe P, a check valve V for preventing backflow, and an auxiliary compressed air input section (nozzle pipe 15) for supplying auxiliary compressed air into the transport pipe P immediately downstream of the check valve V, As a result, the plug-like liquid phase portion 8 that is to be enlarged as it approaches the downstream end in the transport pipe P can be efficiently regenerated into a smaller plug-like liquid phase portion 8. Therefore, even when the transport pipe P is extended for a long distance without providing a relay facility, the individual plug-like liquid phase portions 8 in the plug flow in the transport pipe P are connected to the downstream of the transport pipe P. Since it can be made as small as possible near the end, the back pressure applied to the earth and sand transporter S (ie, the earth and sand supply device SS and the compressed air mixing device SA) is reduced, thereby reducing the original pressure of the earth and sand transporter S. Costs and operating costs can be reduced, and durability of the earth and sand transporter S and the transport pipe P can be improved. In addition, since the aerobic microorganisms in the slurry-like earth and sand are activated by the aeration effect by introducing auxiliary compressed air in the middle of the transport pipe P, the purification efficiency of the earth and sand is enhanced.

By the way, the present inventor conducted an earth and sand transport experiment using the actual machine model 1 to which the present invention was applied and the actual machine model 2 corresponding to the conventional example, and the pipe pressure P at the upstream end of the transport pipe P for each model. ₀ and to measure the pipe pressure P ₁ at a predetermined distance downstream point of the check valve V, as a result, variations in the pressure within the pipe was observed at each measurement point with the plug flow PL flow. In this case, the pipe pressure P ₀ at the upstream end of the transport pipe P corresponds to the original pressure of the earth and sand transporter S, and the amplitude of fluctuation of the pipe pressure P ₁ at a predetermined distance downstream of the check valve V ( It is considered that the pressure difference) corresponds to the sediment transport capacity. As a result of the experiment, even though the original pressure of the sediment transport machine S is almost the same, the actual machine model 1 has the above amplitude (pressure) than the actual machine model 2 It was confirmed that the difference was high and therefore the sediment transport capacity was high.

  Further, in the illustrated example, the bottom surface of the expansion chamber 10 provided immediately downstream of the check valve V is lowered by one step from the bottom surface of the transport pipe P connected immediately upstream thereof, and the step portion is opened to the downstream side of the transport pipe P. Since the auxiliary compressed air introduction part (nozzle tube 15) is provided so as to face the bottom of the expansion chamber 10, the dredged sand 20 (slag flow) can be sufficiently stirred by the auxiliary compressed air so that the dredged sand is expanded. It is possible to effectively prevent precipitation and stagnation at the bottom.

  As mentioned above, although the Example of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.

  For example, in the above-described embodiment, most of the transport pipe P is floated on the surface of the water and laid down to the landfill U as a sediment disposal site. In the present invention, a part or all of the transport pipe P is placed on the ground. You may make it lay.

  Moreover, in the said Example, although the transport pipe P is utilized for the transport of the slurry-like earth and sand (sediment sand) between the mud working ship A and the landfill U as a earth and sand disposal site, in this invention, The starting place and the arrival place of the slurry-like earth and sand are not limited to the embodiment, and can be selected as appropriate.

  Moreover, in the said Example, although what compressed the compressed air from compressed air mixing apparatus SA to the earth-and-sand discharge pipe 4 before the transport pipe P upstream side was shown, in this invention, the compressed air is conveyed to the transport pipe P. You may make it inject directly.

  In the above-described embodiment, the nozzles N and N ′ of the nozzle pipe 7 and the nozzles n and n ′ of the nozzle pipe 15 are arranged in plural (two in the illustrated example) at intervals in the front-rear direction. In the present invention (claims 1 to 4), at least one of the nozzle pipes 7 and 15 may have a single nozzle (for example, only the upstream nozzles N and n).

Overall longitudinal sectional view of pneumatic transportation system for dredged sand according to one embodiment of the present invention Partially broken enlarged vertical sectional view showing the earth and sand transporting machine (enlarged view of arrow 2 in FIG. 1) 3-3 enlarged sectional view of FIG. Longitudinal sectional view of plug flow regenerating means (Expanded longitudinal sectional view taken along arrow 4 in FIG. 1) Sectional view along line 5-5 in FIG. It is a longitudinal cross-sectional view which shows roughly the flow state of the plug flow in the plug flow regeneration means (before and after the check valve), (A) shows the flow state of the liquid phase part, and (B) shows the gas phase part. Indicates flow state The longitudinal cross-sectional view which shows roughly the flow state of the plug flow over the whole transport pipe in the said Example. FIG. 7 correspondence diagram schematically showing the flow state of the plug flow over the entire transport pipe in the conventional example.

P ... transport pipe PL ... plug flow SA ... compressed air mixing device SS ... earth and sand supply device V ... check valve n, n '... nozzle 8 ... plug shape Liquid phase portion 9 ··· Gas phase portion 10 · Expansion chamber 13 · Valve body 15 · Auxiliary compressed air charging nozzle tube 20 as auxiliary compressed air charging portion · · · Slurry earth and sand

Claims (2)

A pneumatic transportation system for slurry-like earth and sand, in which slurry-like earth and sand (20) containing water and having viscosity are pumped by air pressure through the inside of a transportation pipe (P),
The earth and sand supply device (SS) capable of forcibly supplying the slurry-like earth and sand (20) into the transport pipe (P), and the slurry-like earth and sand (SS) supplied into the transport pipe (P) by the earth and sand supply apparatus (SS) ( 20) a compressed air mixing device (SA) capable of mixing compressed air for pressure-feeding the downstream side of the transport pipe (P) into the slurry-like soil (20) at or near the upstream end of the transport pipe (P); With
In the transport pipe (P), along with the mixing of the compressed air, the plug-like liquid phase portion (8) made of the slurry-like earth and sand (20) and the gas phase portion (9) made of the compressed air are in the longitudinal direction of the transport pipe (P). In such a configuration that a plug flow (PL) that flows alternately in the direction and flows in the downstream direction is generated,
In the middle of the transport pipe (P), there is provided a check valve (V) for preventing backflow and an expansion chamber (10) directly facing the downstream side of the valve body (13) of the check valve (V),
In the middle of the transport pipe (P), a check valve (V) for preventing a backflow and an expansion chamber (10) directly facing the downstream side of the plate valve body (13) of the check valve (V) are provided. The upper end of the plate-like valve body (13) is pivotally connected to the upper wall of the expansion chamber (10) so that the plate-like valve body (13) can swing between the open position and the closed position,
An auxiliary compressed air input part (15) having a nozzle (n) for jetting auxiliary compressed air toward the downstream side of the transport pipe (P) is provided at the lower peripheral wall of the expansion chamber (10). Is provided so as to be located immediately below the opening / closing operation region of the plate-shaped valve body (13) ,
The bottom surface of the expansion chamber (10) is lowered by one step from the bottom surface of the transport pipe (P) immediately upstream thereof, and the auxiliary compressed air input portion (15) is provided at the step portion of the injection port (n). the characterized in that it is provided so as to be directed to the transporting pipe (P) downstream, of the slurry-like sediment pneumatic transport systems. The auxiliary compressed air input part (15) has a plurality of injection holes (n, n ′) including the injection holes (n) arranged at intervals in the flow direction of the slurry-like earth and sand (20). The pneumatic transportation system for slurry-like earth and sand according to claim 1, wherein

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