Muddy water pump and packing for muddy water pump

Abstract

To propose a muddy water pump and packing for the muddy water pump that can shorten a work period by reducing replacement work for the packing.SOLUTION: A muddy water pump 1 comprises a casing 2 housing an impeller 6, a main body part 5 for applying a turning force to the impeller 6 via a shaft 51, and a front cover 3 covering a front side of the casing 2, and water stop packing 7 is used in the muddy water pump 1. The water stop packing 7 is interposed between the casing 2 and the front cover 3. The water stop packing 7 is made of ultrahigh molecular weight polyethylene, fluororesin, polyacetal, or polycarbonate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a mud pump and a gasket for a mud pump. [Background technology]

[0002] In the slurry shield tunneling method, slurry is circulated between the aboveground part and the tunnel face to stabilize the tunnel face and to drain excavated soil. A slurry pump is used to circulate the slurry. In addition to shield tunnels, slurry pumps are also used to transport fluids, such as for treating spring water in mountain tunnels and for draining slurry during dredging work. Packings are provided at the joints between the components that make up a muddy water pump in order to prevent leakage of muddy water and the like. For example, Patent Document 1 discloses a pump packing that is provided between a motor casing and an outer casing. Asbestos packing or flange rubber packing (GF packing) is often used for such packing. Also, for example, Patent Document 2 discloses a packing that is disposed adjacent to a pump chamber that discharges liquid by the reciprocating movement of a plunger and slides on the plunger.

[0003] In mud pumps, sudden large pressure changes can occur due to water hammer or blockage of the pump's rotating parts. When a sudden pressure change occurs in a mud pump, the packing breaks, preventing damage to the main body (pump shaft, etc.). On the other hand, if the packing breaks, the pump must be stopped to replace it, and construction must be suspended. In particular, when a large pump is used, the packing replacement work takes time, which may have a significant impact on the construction period. Furthermore, in the case of mud pumps used in mud shield construction methods, etc., the packing replacement work must be done in a narrow space, making it a time-consuming task. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-43286 A [Patent Document 2] Japanese Utility Model Application Publication No. 59-9184 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to propose a muddy water pump and a gasket for a muddy water pump that make it possible to shorten construction time by reducing the amount of gasket replacement work required. [Means for solving the problem]

[0006] In order to solve these problems, the muddy water pump of the present invention is a muddy water pump comprising a casing that houses an impeller, a main body that imparts a rotational force to the impeller via a shaft, and a front cover that covers the front side of the casing. A watertight gasket (muddy water pump gasket) is interposed between the casing and the front cover. Furthermore, when the casing is connected to the main body via a back cover, it is desirable to have a configuration in which a watertight gasket is interposed between the casing and the back cover. The watertight gasket used in such mud water pumps is made of either ultra-high molecular weight polyethylene, fluororesin, polyacetal or polycarbonate, and more preferably is made of ultra-high molecular weight polyethylene having a molecular weight of 1 million or more (1 million to 7 million). Effect of the Invention

[0007] According to the muddy water pump and muddy water pump gasket of the present invention, it is possible to shorten the construction period by eliminating the need for gasket replacement work. [Brief description of the drawings]

[0008] [Figure 1] 1A and 1B are diagrams showing an overview of a muddy water pump of this embodiment, in which (a) is a side view and (b) is a front view. [Diagram 2]FIG. 2 is a cross-sectional view showing an overview of a mud water pump. [Diagram 3] 1A and 1B are diagrams showing a watertight gasket, in which (a) is a plan view and (b) is a side view. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In this embodiment, a mud pump used in a mud shield tunneling method for transporting mud from an aboveground plant to a tunnel face (mud transport) and for transporting mud from the tunnel face to the aboveground (mud discharge) will be described. A mud pump 1 is shown in Fig. 1(a). As shown in Fig. 1(a), the mud pump 1 has a casing 2, a front cover 3, a back cover 4, and a main body 5. Two transport pipes 11, 11 are connected to the mud pump 1, and when the mud pump 1 is driven, it sucks in mud from one transport pipe 11 and pumps it to the other transport pipe 11. For example, when supplying mud to the face, mud is sucked into the casing 2 via the transport pipe 11 extended from the mud plant side, and is pumped to the face side via the transport pipe 11 extending from the casing 2 to the face side.

[0010] A cross-sectional view of the mud water pump 1 is shown in Figure 2. As shown in Figure 2, the casing 2 is a hollow cylindrical member and houses the impeller 6 in its internal space. An inlet and outlet 21 are formed in the casing 2. In this embodiment, the inlet and outlet 21 are formed in the upper part of the casing 2 and open upward. A first flange 22 for connecting the transport pipe 11 is formed in the inlet and outlet 21. A plurality of bolt holes 23, 23, ... are formed at predetermined intervals in the front and rear surfaces of the casing 2.

[0011] As shown in Figs. 1(a) and (b), the front cover 3 covers the opening on the front side of the casing 2. An annular second flange 31 that abuts against the front surface of the casing 2 is formed on the periphery of the front cover 3. As shown in Fig. 2, the front cover 3 is fixed to the front surface of the casing 2 by screwing bolts 8 inserted through the second flange 31 into bolt holes 23 of the casing 2. As shown in Fig. 1(b), an opening 32 is formed in the center of the front cover 3. Note that the central axis of the front cover 3 (opening 32) coincides with the central axis of the impeller 6 as shown in Fig. 2. In addition, the central axis of the opening 32 and the central axis of the inlet / outlet 21 intersect. A third flange 33 to which the transport pipe 11 can be connected is formed on the periphery of the opening 32.

[0012] A water stop gasket 7 is interposed between the casing 2 and the front cover 3. FIG. 3 shows the water stop gasket 7. The water stop gasket 7 interposed between the casing 2 and the front cover 3 is a gasket for a muddy water pump, and may be referred to as a first water stop gasket 71 below. As shown in FIGS. 3(a) and 3(b), the first water stop gasket 71 is an annular plate material with an opening in the center, and is interposed on the contact surface between the casing 2 and the second flange 31 of the front cover 3. The bolt holes 23 of the casing 2 are disposed on the outer periphery of the first water stop gasket 71. The first water stop gasket 71 is made of ultra-high molecular weight polyethylene having a molecular weight of 1 million or more. By adjusting the thickness of the water stop gasket 7, the size of the inner space (discharge flow rate) of the muddy water pump 1 can be adjusted.

[0013] As shown in FIG. 1, the back cover 4 is interposed between the casing 2 and the main body 5. The front side of the back cover 4 is connected to the casing 2, and the rear side is connected to the main body 5. A fourth flange 41 that abuts against the rear surface of the casing 2 is formed on the periphery of the back cover 4. As shown in FIG. 2, the back cover 4 is fixed to the rear surface of the casing 2 by screwing the bolts 8 inserted into the fourth flange 41 into the bolt holes 23 of the casing 2. An insertion hole 42 that rotatably supports the joint between the shaft 51 extending from the main body 5 and the impeller 6 is formed in the center of the back cover 4. That is, the shaft 51 is inserted into the insertion hole 42 and joined to the impeller 6. A shaft sleeve (not shown) is provided in the insertion hole 42 to prevent muddy water in the casing 2 from leaking to the outside. A plurality of bolt holes 43, 43, . . . are formed around the insertion hole 42 of the back cover 4, and the back cover 4 is connected to the main body 5 via bolts 8 screwed into the bolt holes 43.

[0014] A water stop gasket 7 is interposed between the casing 2 and the back cover 4. Hereinafter, the water stop gasket 7 interposed between the casing 2 and the back cover 4 may be referred to as a second water stop gasket 72. The second water stop gasket 72, like the first water stop gasket 71, is an annular plate material with an opening in the center, and is interposed on the contact surface between the fourth flange 41 and the casing 2. The second water stop gasket 72 interposed between the casing 2 and the back cover 4 has a planar shape equivalent to that of the fourth flange 41. Like the first water stop gasket 71, the second water stop gasket 72 is made of ultra-high molecular weight polyethylene having a molecular weight of 1 million or more.

[0015] As shown in FIG. 1(a), the main body 5 is connected to the casing 2 via the back cover 4. The main body 5 has a cylinder 52 that rotatably supports a shaft 51, a prime mover 53 disposed behind the cylinder 52, and a base 54 that supports the cylinder 52 and the prime mover 53. The prime mover 53 is a power source that applies a rotational force to the impeller 6 via the shaft 51. As shown in FIG. 2, the shaft 51 penetrates the cylinder 52. The tip end of the shaft 51 penetrates the insertion hole 42 of the back cover 4 and is connected to the impeller 6. The base end of the shaft 51 is connected to a drive shaft 55 of the prime mover 53 via a coupling means 56. The shaft 51 rotates with the prime mover 53 as a drive source. The central axis of the shaft 51 coincides with the central axis of the impeller 6 and the central axis of the opening 32.

[0016] As shown in Fig. 2, the impeller 6 is rotatably provided in the hollow portion of the casing 2. The impeller 6 has a plurality of blades, and forms a flow of muddy water by rotation. The rotation of the impeller 6 takes in muddy water into the casing 2, and the muddy water taken into the casing 2 is discharged. In this embodiment, when the impeller 6 rotates forward, a flow of muddy water is formed in the casing 2 from the opening 32 toward the inlet / outlet 21, and when the impeller 6 rotates reversely, a flow of muddy water is formed in the casing 2 from the inlet / outlet 21 toward the opening 32.

[0017] According to the muddy water pump 1 of this embodiment, watertight gaskets 7 are interposed between the casing 2 and the front cover 3, and between the casing 2 and the back cover 4, thereby preventing leakage of muddy water. The watertight gasket 7 has excellent elasticity, so even if the pressure inside the muddy water pump 1 (casing 2) becomes negative due to the transport pipe 11 being clogged with sediment or the like, or if the pump rotating part is clogged with sediment and then the blockage is cleared and a large amount of muddy water pressure acts instantaneously, the watertight gasket 7 can deform to absorb the pressure. Therefore, the effect on the shaft sleeve (shaft seal part) is small, and leakage of muddy water into the main body part 5 is suppressed.

[0018] In addition, because the waterstop gasket 7 itself expands and contracts, it will not be damaged by large pressure fluctuations, and this will reduce the frequency of waterstop gasket replacement work, which was frequently required in conventional mud water pumps 1. As such, even in the event of a water hammer or blockage of the pump rotating section, the waterstop gasket 7 is unlikely to be damaged, allowing construction to continue continuously without stopping excavation. The water stop gasket 7 of this embodiment has high impact resistance and its function does not change from low to high temperatures, so it will not break even if it is subjected to a sudden pressure change. In addition, the water stop gasket 7 has excellent lubrication resistance and is unlikely to be worn or damaged due to sliding. In addition, the water stop gasket 7 has low water absorption and is unlikely to change in dimension due to humidity, etc. In other words, the water stop gasket 7 has excellent dimensional stability. In addition, the water stop gasket 7 has high chemical resistance and is unlikely to cause chemical reactions, so it is unlikely to deform even if it comes into contact with chemicals for some reason.

[0019] Although an embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and each component can be appropriately modified without departing from the spirit of the present invention. In the above embodiment, the water-stopping gasket 7 is made of ultra-high molecular weight polyethylene, but the water-stopping gasket 7 is not limited to being made of ultra-high molecular weight polyethylene, and may be made of, for example, fluororesin, polyacetal, or polycarbonate. Since the waterproof packing 7 can be formed to a predetermined thickness, the effort of stacking a plurality of waterproof packings to ensure the predetermined thickness can be eliminated. In the above embodiment, waterproof gaskets 7 made of the same material are interposed between the casing 2 and the front cover 3, and between the casing 2 and the back cover 4, but waterproof gaskets 7 made of different materials may also be interposed in each case. In the above embodiment, the back cover 4 is interposed between the casing 2 and the main body 5, but the back cover 4 may be provided as necessary. [Explanation of symbols]

[0020] 1 Mud pump 11 Transport pipe 2 Casing 21 Inlet / Outlet 22 First flange 23 Bolt holes 3 Front cover 31 Second flange 32 Opening 33 Third flange 4 Back cover 41 Fourth flange 42 Insertion hole 5 Main body 51 Shaft 52 cylinders 53 Prime Mover 54 Foundation 55 Drive shaft 56 Joint means 6 Impeller 7. Water-stop packing (mud pump packing) 71 First watertight packing 72 Second watertight packing 8 Volts

Claims

1. A casing that houses the impeller; A main body that applies a rotational force to the impeller via a shaft; A mud pump comprising: a front cover covering a front side of the casing; A waterproof packing is interposed between the casing and the front cover, A muddy water pump, characterized in that the water-stopping gasket is made of either ultra-high molecular weight polyethylene, fluororesin, polyacetal or polycarbonate.

2. The casing is connected to the main body via a back cover, A waterproof packing is interposed between the casing and the back cover, 2. The muddy water pump according to claim 1, wherein the water-stopping gasket is made of any one of ultra-high molecular weight polyethylene, fluororesin, polyacetal, and polycarbonate.

3. 3. A muddy water pump as claimed in claim 1 or claim 2, characterized in that the water-stopping gasket is made of ultra-high molecular weight polyethylene having a molecular weight of 1 million or more.

4. A mud pump packing for a mud pump including a casing that houses an impeller and a cover attached to the casing, the packing being interposed between the casing and the cover, A gasket for a muddy water pump, characterized in that it is made of either ultra-high molecular weight polyethylene, fluororesin, polyacetal or polycarbonate.

5. The gasket for a muddy water pump according to claim 4, characterized in that it is made of ultra-high molecular weight polyethylene having a molecular weight of 1 million or more.

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