Concrete force-feeding method

Abstract

To provide a concrete force-feeding technology capable of preventing blockage of a concrete transport pipe without using advance mortar in a concrete pouring work.SOLUTION: A concrete force-feeding method for force-feeding fresh concrete in a hopper through a concrete transport pipe using a pump during a concrete pouring work includes the steps of: attaching a concrete receiver to a tip of the concrete transport pipe to prevent scattering of discharged fresh concrete; pouring fresh concrete into the hopper without using advance mortar and force-feeding the same using the pump, and injecting compressed air into the concrete transport pipe through an air injection portion provided near a base end of the concrete transport pipe connected to the hopper; and after the fresh concrete is discharged from the tip of the concrete transport pipe, stopping injection of the compressed air while continuing force-feeding using the pump.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a technique for pumping fresh concrete in a hopper through a concrete delivery pipe using a pump during concrete placement work.

Background Art

[0002] When performing concrete placement work, fresh concrete is transported to the construction site by a mixer truck, transferred from the drum of the mixer truck into the hopper of a vehicle equipped with a pump, and pumped from the hopper to a desired placement location via a concrete delivery pipe by the pump. In such concrete pumping by a concrete pump during concrete placement work, various problems such as blockage in the concrete delivery pipe and separation of concrete components can occur.

[0003] Therefore, in concrete placement work, it is a common practice to prevent blockage of the pipe by flowing a cement paste or mortar that does not contain aggregates through the pipe before pumping the fresh concrete to coat the inner wall surface of the pipe with the cement paste. The cement paste or mortar thus used is called a lead mortar.

[0004] Patent Document 1 below discloses an apparatus for monitoring blockage of a pipe through which fresh concrete is pumped. This apparatus is attached to the outer wall side of the pipe through which fresh concrete is pumped, and includes a sound sensor that detects the frictional sound between the fresh concrete being pumped and the inner wall of the pipe, means for determining whether the material of the fresh concrete is separated from the frictional sound detected by the sound sensor, and monitoring result output means for outputting the determination result of this means.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In conventional mortar, mortar with a mixing ratio called 1:3 mortar or 1:2 mortar (3 kg or 2 kg of sand per 1 kg of cement) is generally used. For this reason, the strength required for fresh concrete for placement (specified by JIS) cannot be ensured by the conventional mortar, and it is not allowed to place it together with the fresh concrete. Therefore, the conventional mortar is discarded as industrial waste, but the disposal of the conventional mortar not only wastes resources but also incurs unnecessary costs.

[0007] The present invention has been made in view of such circumstances, and provides a concrete pumping technique capable of preventing blockage of a concrete transport pipe without using conventional mortar in a concrete placement work.

Means for Solving the Problems

[0008] One aspect of the present invention is a concrete pumping method for pumping fresh concrete in a hopper through a concrete transport pipe using a pump during a concrete placement work, including a step of attaching a concrete receiver for suppressing scattering of the discharged fresh concrete to the tip of the concrete transport pipe, a step of charging fresh concrete into the hopper without using conventional mortar and pumping it by the pump, and a step of injecting compressed air into the concrete transport pipe from an air injection portion provided near the base end portion of the concrete transport pipe connected to the hopper, and a step of stopping the injection of the compressed air while continuing the pumping by the pump after the fresh concrete is discharged from the tip of the concrete transport pipe.

[0009] Another aspect of the present invention is a concrete receiver used in the above-described concrete pumping method, which includes a detachable mounting portion at the tip of a concrete transport pipe, and a protective wall disposed at a position a predetermined distance away from the concrete discharge port of the tip of the concrete transport pipe while facing the concrete discharge port of the tip of the concrete transport pipe in a state of being mounted on the tip of the concrete transport pipe by the mounting portion, and a connecting portion that connects the protective wall and the mounting portion and has a gap through which the fresh concrete discharged from the concrete discharge port can pass.

[0010] Another aspect of the present invention is an air injection device provided in the vicinity of the base end portion connected to the hopper in the concrete transport pipe and used in the above-described concrete pumping method. The air injection device includes a body portion having a relay passage connected to the tip-side partial pipe and the hopper-side partial pipe that constitute the concrete transport pipe and capable of communicating the hollows of both partial pipes, and a valve body that enables switching between a state where the hollow of an air transport pipe that transports compressed air supplied from an air compressor communicates with the relay passage and a state where the hollow of the air transport pipe is blocked from the relay passage.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a concrete pumping technique for preventing blockage of a concrete transport pipe without using prior mortar in concrete placement work.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are examples, and the present invention is not limited to the configurations of the following embodiments.

[0014] FIG. 1 is a diagram showing an example of a concrete pump truck 1 using the concrete pumping method according to the present embodiment (hereinafter, may also be referred to as this pumping method). The concrete pump truck 1 illustrated in FIG. 1 includes a self - propelled vehicle 2, and a hopper 3, a concrete transport pipe 5, a concrete pump (not shown), a boom 4, etc. are provided on the vehicle 2.

[0015] The hopper 3 is provided at the rear of the vehicle 2, has an opening upward, and stores the fresh concrete introduced from a concrete mixer truck through the opening. The concrete pump pumps the fresh concrete in the hopper 3 into the concrete transport pipe 5. For example, a hydraulic piston pump is used for the concrete pump. However, the concrete pump only needs to be able to pump fresh concrete, and its specific configuration is not limited. For example, a hydraulic piston pump or a squeeze - type pump may be used for the concrete pump.

[0016] The concrete transport pipe 5 is a pipe that transports the fresh concrete sent out from the hopper 3 to a desired placing location. The concrete transport pipe 5 is connected to the hopper 3 at the base end such that the hollow part communicates with the inside of the hopper 3, and extends along the boom 4. In the example of FIG. 1, the concrete transport pipe 5 is configured by connecting a plurality of pipes of various shapes, such as a straight pipe and a curved pipe, with a connecting member. For example, the tip of the concrete transport pipe 5 is formed of rubber, synthetic resin, or the like called a material hose 6. However, in this embodiment, the shape and material of the concrete transport pipe 5 are not limited.

[0017] The boom 4 supports the concrete transport pipe 5 at a plurality of locations by a plurality of pipe support portions 4a, and enables the tip of the concrete transport pipe 5 to be arranged at a desired placement location. In the example of FIG. 1, the boom 4 is composed of a plurality of partial booms in a multi-stage manner, and each partial boom can be extended by rotating at a connecting portion. However, in this embodiment, the shape and specific structure of the boom 4 are not limited at all.

[0018] An air injection portion 10 is provided in the concrete transport pipe 5 used in this pumping method. The air injection portion 10 is a means for sending compressed air into the concrete transport pipe 5 in order to further pneumatically transport the fresh concrete pumped through the concrete transport pipe 5 by pump pressure. The air injection portion 10 is preferably provided near the base end portion connected to the hopper 3 in the concrete transport pipe 5. Specifically, the air injection portion 10 is preferably provided between the connecting portion with the hopper 3 at the base end portion of the concrete transport pipe 5 and the pipe support portion 4a at the position closest to the hopper 3 in the boom 4. By arranging the air injection portion 10 in such a manner, it becomes easier to install the air transport pipe 18 and the air compressor 19 described later. That is, the installation position of the air injection portion 10 in the concrete transport pipe 5 is a position as close as possible to the base end portion in the concrete transport pipe 5, and is preferably a linear position where it is easy to install the air transport pipe 18 and the air compressor 19. For example, as the vicinity of the base end portion of the concrete transport pipe 5 where the air injection portion 10 is installed, it is a position closer to the base end portion than one-fourth of the total length of the concrete transport pipe 5 (the length between the base end portion and the tip).

[0019] Figure 2 is a schematic diagram of the air injection unit 10. In the example of FIG. 1, the air injection unit 10 is interposed between the connection portion with the hopper 3 in the concrete transport pipe 5 and the support portion (pipe support portion 4a) at the boom 4. The air injection unit 10 preferably communicates the air transport pipe 18 that transports the compressed air supplied from the air compressor 19 with the concrete transport pipe 5, and is configured such that the compressed air injected from the air transport pipe 18 into the concrete transport pipe 5 advances in a spiral shape toward the tip of the concrete transport pipe 5. According to such a configuration, it is possible to efficiently apply the pushing force of the compressed air to the fresh concrete in the concrete transport pipe 5. As a result, by further pushing the fresh concrete pumped under pump pressure in the concrete transport pipe 5 with compressed air, the flow rate of the fresh concrete can be increased and the film of the fresh concrete can be adhered to the inner surface of the concrete transport pipe 5, and it becomes possible to prevent pipe blockage without using the preceding mortar.

[0020] The air injection unit 10 mainly has a relay pipe body 11, an injection pipe portion 13, and an air injection valve 14. The relay pipe body 11 is connected to the tip-side partial pipe and the hopper 3-side partial pipe that constitute the concrete transport pipe 5, and has a relay passage inside that can communicate the hollows of both partial pipes. This relay passage serves as the flow path for the fresh concrete. That is, the relay pipe body 11 forms a part of the concrete transport pipe 5. The connection between the relay pipe body 11 and each partial pipe constituting the concrete transport pipe 5 may be performed using a general connecting member.

[0021] The injection pipe portion 13 protrudes from the relay pipe body 11 and is connected to the air injection valve 14 at its end. The injection pipe portion 13 has an air passage inside that communicates with the relay passage of the relay pipe body 11, and the compressed air supplied from the air compressor 19 is injected into the relay passage of the relay pipe body 11 through this air passage. That is, the compressed air supplied from the air compressor 19 is injected into the concrete transport pipe 5 using the hollows in the air transport pipe 18, the air passages in the air injection valve 14, and the air passage in the injection pipe portion 13 as flow paths. As described above, the relay pipe body 11 and the injection pipe portion 13 have an inlet port 12a, an outlet port 12b, and an injection port 12c. Fresh concrete enters the relay passage in the relay pipe body 11 from the inlet port 12a, compressed air is injected into the relay passage in the valve body 11 from the injection port 12c through the air passage of the injection pipe portion 13, and fresh concrete is pushed out from the outlet port 12b.

[0022] In order for the compressed air injected into the concrete transport pipe 5 to advance in a spiral shape, it is preferable that the internal air passage of the injection pipe portion 13 is formed at an angle as shown in FIGS. 2(b) and 2(c). FIGS. 2(b) and 2(c) show a side view of the air injection portion 10 viewed from the side and a plan view of the air injection portion 10 viewed from above as directions orthogonal to the flow path direction of the concrete flow path formed by the concrete transport pipe 5 and the relay pipe body 11. As shown in FIG. 2(c), the air passage of the injection pipe portion 13 preferably communicates with the relay passage of the relay pipe body 11 at an angle of about 30 degrees in plan view, and as shown in FIG. 2(b), preferably communicates with the relay passage of the relay pipe body 11 at an angle of about 15 degrees in side view. In FIGS. 2(b) and 2(c), for easy understanding of the explanation, the extending direction of the injection pipe portion 13 itself with respect to the relay pipe body 11 is shown, but the positional relationship between the relay passage of the relay pipe body 11 and the air passage of the injection pipe portion 13 may be as described above. Also, the angle is allowed to be in the range of plus or minus 5 degrees to 10 degrees from the value shown in FIG. 2. Further, in FIG. 2, the angles in plan view and side view are shown, but as long as the respective line-of-sight directions are orthogonal to each other and orthogonal to the flow path direction of the concrete flow path, the angles in plan view and side view are not necessary.

[0023] The air injection valve 14 is a two-way valve connected to the injection pipe portion 13 and the air transport pipe 18, and can adjust or stop the injection amount of compressed air. Specifically, the air injection valve 14 has a valve body 15, a valve handle 16, a valve body (not shown), etc. The valve body 15 has an air passage inside that can connect the air passage of the injection pipe portion 13 and the hollow inside the air transport pipe 18, and this air passage serves as the flow path for the compressed air. Note that the connection between the valve body 15, the injection pipe portion 13, and the air transport pipe 18 may be made using a general connecting member. Also, the valve body 15 and the injection pipe portion 13 may be integrally molded.

[0024] The valve element is provided inside the valve body 15, moves to adjust the injection of the compressed air supplied from the air compressor 19, and realizes the closing function of the compressed air injection by closely contacting the valve seat in the valve closed state. Specifically, the valve element enables switching between a state where the hollow of the air transport pipe 18 communicates with the relay passage in the relay pipe body 11 via the air passage of the valve body 15 and the air passage of the injection pipe portion 13 (hereinafter referred to as the open state) and a state where the hollow of the air transport pipe 18 is blocked from the relay passage via the air passage of the valve body 15 and the air passage of the injection pipe portion 13 (hereinafter referred to as the closed state). Hereinafter, for the convenience of explanation, the open state and the closed state switched by the valve element of the air injection valve 14 may also be referred to as the open state and the closed state of the air injection portion 10. That is, when the air injection portion 10 is in the open state, the compressed air is injected into the concrete transport pipe 5, and when the air injection portion 10 is in the closed state, the compressed air is not injected into the concrete transport pipe 5.

[0025] The valve handle 16 is rotatably supported with respect to the valve body 15, and the valve element can be moved along with its rotation. That is, the valve handle 16 enables the switching operation of the open / closed state of the air injection portion 10. However, in the example of FIG. 2, the air injection valve 14 may be an electromagnetic valve that includes the valve handle 16 and enables the switching of the open / closed state by electronic control.

[0026] In the air injection part 10 illustrated in FIG. 2 as described above, an air injection valve 14 is connected to an injection pipe part 13 protruding from a relay pipe body 11. In this way, by providing the air injection valve 14 in an air flow path at a position separated from the relay passage that serves as a concrete flow path, it is possible to prevent the valve body and the like from being worn or damaged by the flow of fresh concrete. Further, a hose or a pipe may be provided between the air injection valve 14 and the injection pipe part 13.

[0027] In this pumping method, furthermore, a concrete receiver 20 is used. The concrete receiver 20 is detachably attached to the tip of the concrete transport pipe 5 (the tip of the material hose 6) in order to suppress the scattering of the discharged fresh concrete. FIG. 3 is a diagram schematically showing the concrete receiver 20 attached to the concrete transport pipe 5, and FIG. 4 is an exploded view of the concrete receiver 20 when attached to the concrete transport pipe 5. As shown in FIGS. 3 and 4, the concrete receiver 20 is composed of a mounting part 21, a protective wall 22, a connecting part 23, an inner packing 25, and the like. However, the structure of the concrete receiver 20 shown in FIGS. 3 and 4 is only an example, and the structure of the concrete receiver 20 used in this pumping method is not limited to the examples in FIGS. 3 and 4.

[0028] The mounting part 21 is configured to be wound around the outer periphery of the tip of the concrete transport pipe 5 like a lock via an inner packing 25, and with this configuration, the concrete receiver 20 can be detachably attached to the concrete transport pipe 5. In the examples of FIGS. 3 and 4, the mounting part 21 includes a fixed curved part 21a and a movable curved part 21b. The fixed curved part 21a and the movable curved part 21b are each curved in a substantially semicircular shape, and one end is rotatably connected by a hinge structure. Further, a locking shaft 21d and a locking operation part 21e are rotatably provided at the other end of the fixed curved part 21a, and a locking recess 21c is provided at the other end of the movable curved part 21b. As a result, by joining the ends of the fixed bending part 21a and the movable bending part 21b and inserting the locking shaft 21d of the fixed bending part 21a into the locking recess 21c of the movable bending part 21b, the fixed bending part 21a and the movable bending part 21b can be annularly connected. Further, as shown in FIG. 3, by rotating the locking operation part 21e in a state where the locking shaft 21d is inserted into the locking recess 21c to shorten the exposed length of the locking shaft 21d, the joining degree between the ends of the fixed bending part 21a and the movable bending part 21b can be increased. Thereby, the tightening of the mounting part 21 on the outer periphery of the tip of the concrete conveying pipe 5 via the inner packing 25 can be strengthened, and the mounting strength of the concrete receiver 20 on the concrete conveying pipe 5 can be increased.

[0029] The protective wall 22 is arranged at a position separated by a predetermined distance from the concrete discharge port while facing the concrete discharge port at the tip of the concrete conveying pipe 5 in a state where the concrete receiver 20 is mounted on the tip of the concrete conveying pipe 5 by the mounting part 21. By arranging the protective wall 22 so as to face the concrete discharge port in this way, the scattering of the fresh concrete discharged from the concrete discharge port forward can be prevented. Also, although the momentum of the discharge of the fresh concrete pumped by pump pressure and air pressure is formidable, by arranging the protective wall 22 at a position separated by a predetermined distance, the momentum of the lateral scattering of the fresh concrete coming into contact with the protective wall 22 can also be suppressed. Also, in the examples of FIGS. 3 and 4, the protective wall 22 is formed of a curved plate material protruding in a direction away from the tip of the concrete conveying pipe 5. Even with such a shape, the momentum of the lateral scattering of the fresh concrete coming into contact with the protective wall 22 can be suppressed.

[0030] The connecting part 23 connects the protective wall 22 and the mounting part 21 so that the protective wall 22 is fixed at a position separated by a predetermined distance from the concrete discharge port, and has a gap through which the fresh concrete discharged from the concrete discharge port of the concrete conveying pipe 5 can pass. In the examples of FIGS. 3 and 4, the connecting portion 23 is composed of vertical grids arranged along the outer periphery of the protective wall 22 and the mounting portion 21. As a result, gaps are formed between the vertical grids, and the fresh concrete is discharged therefrom.

[0031] This pumping method is performed, for example, using the above-described configuration in the concrete pump truck 1. In this example, this pumping method is from the concrete pump truck 1 having at least the hopper 3, a concrete pump for pumping the fresh concrete in the hopper 3 into the concrete delivery pipe 5, and a boom 4 for supporting the concrete delivery pipe 5, and pumps the fresh concrete via the concrete delivery pipe 5 during the concrete placing work. Thus, this pumping method is a method used in concrete placing work. Here, "concrete placing" means pouring and filling fresh concrete into a specific place such as a formwork.

[0032] This pumping method includes a step of attaching a concrete receiver 20 for suppressing the scattering of the discharged fresh concrete to the tip of the concrete delivery pipe 5, a step of charging fresh concrete into the hopper 3 without using the preceding mortar and pumping it by a concrete pump, and injecting compressed air into the concrete delivery pipe 5 from an air injection portion 10 provided between the connecting portion of the concrete delivery pipe 5 with the hopper 3 to the support portion (pipe support portion 4a) on the boom 4, and a step of stopping the injection of compressed air while continuing the pumping by the concrete pump after the fresh concrete is discharged from the tip of the concrete delivery pipe 5.

[0033] Thus, in this pumping method, by injecting compressed air into the concrete delivery pipe 5 through the air injection part 10 provided near the base end part connected to the hopper 3 in the concrete delivery pipe 5 (in the example of FIG. 1, between the connection part with the hopper 3 in the concrete delivery pipe 5 and the support part (pipe support part 4a) by the boom 4), the fresh concrete being pumped through the concrete delivery pipe 5 is further pumped by the compressed air. As a result, the flow velocity of the fresh concrete in the pipe can be increased to ensure that the fresh concrete flows, a concrete film can be formed on the inner surface of the pipe, and ultimately, blockage can be prevented without using the preceding mortar.

[0034] By the way, in the tunnel excavation site, a concrete spraying machine is used, and in that concrete spraying machine, fresh concrete is sprayed onto the wall surface or the like by compressed air. Thus, in the concrete spraying process in the tunnel excavation work, since fresh concrete must be sprayed onto the wall surface or the like, it is sprayed by compressed air. However, in the concrete placing work, if fresh concrete is sprayed, it will not be possible to place it properly due to the scattering of the concrete to the surroundings. In addition, the aggregate of the fresh concrete used in the concrete placing (for example, about 20 mm to 40 mm) is larger than the aggregate of the fresh concrete used in the spraying in the tunnel excavation work (for example, 15 mm or less). Therefore, the scattering of the fresh concrete in the concrete placing work may be dangerous. Against this background, while it is customary to prevent blockage by using the preceding mortar in the concrete placing work, in this pumping method, while aiming to increase the flow velocity of the fresh concrete by applying air pressure in addition to the pump pressure to ensure that it flows surely inside the pipe, the scattering of the fresh concrete is prevented by attaching the concrete receiver 20 to the tip of the concrete delivery pipe 5. Furthermore, in this pumping method, after the fresh concrete is discharged, while continuing the pumping by the concrete pump, the feeding of the compressed air is stopped to surely suppress the scattering of the fresh concrete.

[0035] Here, specific examples of this pumping method are given below. However, this pumping method is not limited to the following specific examples. (Step 1) Attach the concrete receiver 20 to the tip of the concrete transport pipe 5 (material hose 6). (Step 2) Operate the concrete pump. (Step 3) Operate the air compressor 19 to store compressed air in the air tank (not shown). At this time, the air injection part 10 is in a closed state. (Step 4) Flow the preceding water through the concrete transport pipe 5. If there is water accumulated in the hopper 3, that water can be flowed, or new water can be put into the hopper 3. (Step 5) Switch the air injection part 10 from the closed state to the open state. At this time, compressed air has not been injected into the concrete transport pipe 5 yet. (Step 6) Drain the water remaining in the hopper 3. (Step 7) Charge the fresh concrete into the hopper 3 and start the pump-pumping by the concrete pump. (Step 8) Open the air tank. Thereby, compressed air is injected into the concrete transport pipe 5. (Step 9) Confirm that the fresh concrete discharges from the tip of the concrete transport pipe 5 (material hose 6). (Step 10) When the discharge of the fresh concrete is confirmed, stop the compressed air. This may be achieved by switching the air injection part 10 to the closed state, or by closing the air tank. At this time, since the concrete pump is still operating, the pump-pumped fresh concrete continues to be discharged, and the concrete placing work can be carried out. When the discharge of the fresh concrete is confirmed, since the inner surface of the pipe of the concrete transport pipe 5 is already covered with a concrete film, blockage does not occur.

[0036] [Modification Example] The above-described embodiment is an example of a concrete pumping method and the configuration used therein. The concrete pumping method and the configuration used therein are not limited to only the above examples, and may be partially and appropriately modified.

[0037] For example, the concrete receiver 20 is not limited to the structure shown in FIGS. 3 and 4. In the illustrated example, the protective wall 22 has a curved shape protruding in a direction away from the tip of the concrete transport pipe 5, but it may have a flat plate shape. In the illustrated example, the connecting portion 23 is formed in a vertical grid pattern arranged along the outer peripheries of the protective wall 22 and the mounting portion 21, but it only needs to have a gap through which the fresh concrete discharged from the concrete discharge port can pass, and it may be formed in a vertical and horizontal grid pattern or in a side wall shape having a gap. Also, regarding the mounting portion 21, in the illustrated example, it has a structure that is mounted so as to wrap around the outer periphery of the tip of the concrete transport pipe 5, but it only needs to have a structure that can be detachably mounted to the tip of the concrete transport pipe 5.

[0038] FIG. 5 is a view showing a modified example of the concrete receiver 20. The concrete receiver 20 may further include a stretchable covering member 28 that covers the gap of the connecting portion 23. In this way, it is possible to prevent the scattering of fine concrete particles discharged from the tip of the concrete transport pipe 5. The material and production method of the covering member 28 are not limited at all. The covering member 28 may be made of chemical fibers such as nylon or polyurethane or natural fibers, or may be formed by weaving composite fibers.

[0039] Also, the configuration of the air injection portion 10 is not limited to the example shown in FIGS. 1 and 2. In the air injection portion 10 in the above-described embodiment, the relay pipe body 11 connected to the concrete transport pipe 5 and the air injection valve 14 were provided separately, but as shown in FIG. 6, the air injection portion 10 may be configured as a three-way valve.

[0040] FIG. 6 is a schematic view showing a modified example of the air injection section. The air injection section in the modified example is denoted by reference numeral 30. The air injection section 30 in the modified example is a three-way valve and has a valve body 31, an injection pipe section 33, a valve handle 34, a valve element (not shown), and the like. The valve body 31 is connected to the tip-side partial pipe constituting the concrete transport pipe 5 and the partial pipe on the hopper 3 side, and has an internal relay passage that can communicate the hollows of both partial pipes. This relay passage serves as the flow path for the fresh concrete. That is, the valve body 31 forms a part of the concrete transport pipe 5. The connection between the valve body 31 and each partial pipe constituting the concrete transport pipe 5 may be made using a general connecting member.

[0041] The injection pipe section 33 projects from the valve body 31 and is connected to the air transport pipe 18 at its end. The injection pipe section 33 has an air passage inside that communicates the hollow of the air transport pipe 18 and the relay passage of the valve body 31. Therefore, the hollow of the air transport pipe 18 and the air passage communicating therewith serve as the flow path for the compressed air supplied from the air compressor 19. As described above, the air injection section 30 has an inlet port 32a, an outlet port 32b, and an injection port 32c. Fresh concrete enters the relay passage in the valve body 31 from the inlet port 32a, compressed air enters the relay passage in the valve body 31 from the injection port 32c, and the fresh concrete is pushed out from the outlet port 32b. Similar to the injection pipe section 13 in the above-described embodiment, the injection pipe section 33 preferably has an internal air passage formed at an angle as shown in FIGS. 2(b) and 2(c) so that the compressed air injected into the concrete transport pipe 5 advances in a spiral shape.

[0042] The valve body is provided inside the valve body 31 and moves to adjust the injection of compressed air supplied from the air compressor 19 into the concrete transport pipe 5, and in the valve closed state, it is in close contact with the valve seat to realize the closing function of the air injection part 30. Specifically, the valve body can switch between a state where the hollow of the air transport pipe 18 communicates with the relay passage in the valve body 31 through the air passage of the injection pipe part 33 (hereinafter referred to as the open state) and a state where the hollow of the air transport pipe 18 is blocked from the relay passage through the air passage of the injection pipe part 33 (hereinafter referred to as the closed state).

[0043] The valve handle 34 is rotatably supported with respect to the valve body 31, and the valve body can be moved along with its rotation. That is, the valve handle 34 enables the switching operation of the open / closed state of the air injection part 30. However, in the example of FIG. 6, the air injection part 30 may be an electromagnetic valve that is provided with the valve handle 34 and enables the switching of the open / closed state by electronic control.

[0044] FIG. 7 is a diagram showing another example of the concrete pump truck 1 that uses the concrete pumping method according to the present embodiment. In the above-described concrete pumping method, the concrete pump truck 1 illustrated in FIG. 1 is used, but in tunnel construction, a concrete pump truck 1 as illustrated in FIG. 7 may be used. The concrete pump truck 1 illustrated in FIG. 7 does not include the boom 4, but includes at least the hopper 3 and the pump.

[0045] The above-described concrete pumping method can also be used when placing concrete in tunnel construction using the concrete pump truck 1 shown in FIG. 7. For example, when placing concrete on the inner peripheral surface of a tunnel using a semi-cylindrical movable formwork called a centor, the concrete pumping method can be used. In this case, the fresh concrete in the hopper 3 is pumped to the centor through the concrete transport pipe 5 using the pump mounted on the concrete pump truck 1. Even in this case, the air injection part 10 may be provided near the base end part that connects to the hopper 3 in the concrete transport pipe 5. In the example of FIG. 7, the air injection part 10 is provided at a position near the base end part in the concrete transport pipe 5, where the concrete transport pipe 5 starts to become straight when viewed from the base end part.

[0046] The content of each of the above-described embodiments can also be specified as follows. (Appendix 1) A concrete pumping method for pumping fresh concrete in a hopper through a concrete transport pipe using a pump during concrete placement work, a step of attaching a concrete receiver for suppressing the scattering of the discharged fresh concrete to the tip of the concrete transport pipe; a step of injecting compressed air into the concrete transport pipe from an air injection part provided near the base end part connected to the hopper in the concrete transport pipe while charging fresh concrete into the hopper without using prior mortar and pumping it by the pump; a step of stopping the injection of the compressed air while continuing the pumping by the pump after the fresh concrete is discharged from the tip of the concrete transport pipe; A concrete pumping method including the above steps. (Appendix 2) The concrete receiver is a detachable mounting part at the tip of the concrete transport pipe, a protective wall arranged at a position facing the concrete discharge port at the tip of the concrete transport pipe and separated from the concrete discharge port by a predetermined distance while being mounted at the tip of the concrete transport pipe by the mounting part, a connecting part having a gap through which the fresh concrete discharged from the concrete discharge port can pass while connecting the protective wall and the mounting part so that the protective wall is fixed at the position; comprising The concrete pumping method according to Appendix 1. (Appendix 3) The concrete receiver further includes a stretchable covering member that covers the gap of the connecting portion. The concrete pumping method according to appended note 2. (Appended note 4) The air injection part is configured to communicate an air transport pipe that transports compressed air supplied from an air compressor with a concrete transport pipe, and to allow the compressed air injected into the concrete transport pipe to proceed in a spiral shape toward the tip of the concrete transport pipe. The concrete pumping method according to any one of appended notes 1 to 3. (Appended note 5) A concrete receiver used in the concrete pumping method according to any one of appended notes 1 to 4, a detachable mounting part at the tip of a concrete transport pipe, a protective wall disposed at a position a predetermined distance away from the concrete discharge port of the tip of the concrete transport pipe while facing the concrete discharge port of the tip of the concrete transport pipe in a state of being mounted on the tip of the concrete transport pipe by the mounting part, a connecting part that connects the protective wall and the mounting part so that the protective wall is fixed at the position and has a gap through which the fresh concrete discharged from the concrete discharge port can pass, A concrete receiver comprising: (Appended note 6) An air injection device used in the concrete pumping method according to any one of claims 1 to 4 and provided in the vicinity of the base end portion connected to the hopper in the concrete transport pipe, a body portion having a relay passage that is connected to the tip-side partial pipe and the hopper-side partial pipe constituting the concrete transport pipe and that can communicate the hollows of both partial pipes, a valve body that enables switching between a state in which the hollow of an air transport pipe that transports compressed air supplied from an air compressor communicates with the relay passage and a state in which the hollow of the air transport pipe is blocked from the relay passage, An air injection device comprising: (Appended note 7) an injection pipe portion that protrudes from the body portion and has an air passage inside that communicates with the relay passage of the body portion, an air injection valve connected to the injection pipe portion and the air transport pipe; further comprising the air injection valve enables adjustment and shut-off of the flow rate of the compressed air sent from the air transport pipe into the air passage of the injection pipe portion the air injection device according to Supplementary Note 6. (Supplementary Note 8) a concrete receiver according to Supplementary Note 5, further comprising a stretchable covering member that covers the gap of the connecting portion concrete receiver. (Supplementary Note 9) an air injection device according to Supplementary Note 6 or 7, an air transport pipe that transports compressed air supplied from an air compressor is communicated with a concrete transport pipe, and the compressed air injected into the concrete transport pipe is configured to travel in a spiral shape toward the tip of the concrete transport pipe air injection device.

Explanation of Signs

[0047] 1 concrete pump truck, 2 vehicle, 3 hopper, 4 boom, 4a pipe support portion, 5 concrete transport pipe, 6 material hose, 10 air injection portion, 11 relay pipe body, 12a inlet port, 12b outlet port, 12c injection port, 13 injection pipe portion, 14 valve handle, 18 air transport pipe, 19 air compressor, 20 concrete receiver, 21 mounting portion, 22 protective wall, 23 connecting portion, 25 inner packing, 28 covering member, 30 air injection portion, 31 valve body, 32a inlet port, 32b outlet port, 32c injection port, 33 injection pipe portion, 34 valve handle

Claims

1. A concrete pumping method for pumping ready mixed concrete in a hopper through a concrete transport pipe using a pump during concrete pouring work, A step of attaching a concrete receiver to the tip of the concrete transport pipe to suppress scattering of discharged fresh concrete; A process of pouring ready mixed concrete into the hopper without using a preliminary mortar and pumping it with the pump, and injecting compressed air into the concrete transport pipe from an air injection part provided in the vicinity of a base end of the concrete transport pipe that is connected to the hopper; After the ready-mixed concrete is discharged from the tip of the concrete transport pipe, the injection of the compressed air is stopped while continuing the pumping by the pump; A method for pumping concrete comprising the steps of:

2. The concrete receiver is A detachable attachment part at the tip of the concrete transport pipe; a protective wall that is disposed at a position facing a concrete discharge port at the end of the concrete transport pipe and at a predetermined distance from the concrete discharge port when the protective wall is attached to the end of the concrete transport pipe by the attachment portion; A connecting portion that connects the protective wall and the mounting portion so that the protective wall is fixed at the position and has a gap through which the fresh concrete discharged from the concrete discharge port can pass; Equipped with The method for pumping concrete according to claim 1.

3. The concrete receiver further includes a stretchable covering member that covers the gap of the connecting portion. The method for pumping concrete according to claim 2.

4. The air injection section is configured to communicate an air transport pipe for transporting compressed air supplied from an air compressor with a concrete transport pipe, and the compressed air injected into the concrete transport pipe advances in a spiral shape toward the tip of the concrete transport pipe. The method for pumping concrete according to any one of claims 1 to 3.

5. A concrete receiver used in the concrete pumping method according to any one of claims 1 to 3, A detachable attachment part at the tip of the concrete transport pipe; a protective wall that is disposed at a position facing a concrete discharge port at the end of the concrete transport pipe and at a predetermined distance from the concrete discharge port when the protective wall is attached to the end of the concrete transport pipe by the attachment portion; A connecting portion that connects the protective wall and the mounting portion so that the protective wall is fixed at the position and has a gap through which the fresh concrete discharged from the concrete discharge port can pass; A concrete receiving device comprising:

6. An air injection device used in the concrete pumping method according to any one of claims 1 to 3 and provided in the vicinity of a base end of a concrete transport pipe that is connected to the hopper, a body portion connected to the tip side partial pipe and the hopper side partial pipe constituting the concrete transport pipe and having a relay passage capable of communicating the hollows of both partial pipes; a valve body that enables switching between a state in which the hollow of an air transport pipe that transports compressed air supplied from an air compressor is in communication with the relay passage and a state in which the hollow of the air transport pipe is cut off from the relay passage; An air injection device comprising:

7. an injection pipe portion protruding from the body portion and having an air passage therein that communicates with the relay passage of the body portion; an air injection valve connected to the injection pipe portion and the air transport pipe; Further comprising: The air injection valve enables adjustment and blocking of the flow rate of the compressed air fed from the air transport pipe to the air passage of the injection pipe portion.

7. The air injection device of claim 6.

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