Front casing for slurry pump

Abstract

To provide a front casing for a slurry pump capable of improving maintenance workability of a liquid contact part of the casing.SOLUTION: A front casing 11 is used for a slurry pump 100 in which a rubber casing liner 9 is installed in a casing 1. The front casing 11 is made of an aluminum alloy, is disposed to face the back casing 12 constituting the rear portion of the casing 1 in the front in the axial direction, and is coupled to the back casing 12 by a plurality of bolt fastening portions 18.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a slurry pump having a casing fitted with a rubber liner and used for pumping slurry, and more particularly to a front casing for a slurry pump used in this type of slurry pump. [Background technology]

[0002] This type of slurry pump is sometimes used to pump highly corrosive slurries, so the rubber liner is a consumable part, and maintenance of the liquid-contacting parts is therefore required periodically or depending on the wear state of the rubber liner (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2007-511698 Summary of the Invention [Problem to be solved by the invention]

[0004] When performing maintenance on the liquid-contacting parts, it is necessary to remove the front casing that forms the front of the casing and open the liquid-contacting parts. However, for medium-sized or larger slurry pumps (for example, those with a cast iron front casing weighing 23 kg or more), the front casing of a conventional cast iron (FC200) casing weighs 20 kg or more. This makes maintenance difficult for a single worker, requiring multiple workers or a crane or other lifting equipment. Therefore, there is a strong demand for improved maintenance work on the liquid-contacting parts, especially in factories that handle a large number of pumps.

[0005] The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a front casing for a slurry pump that can improve the ease of maintenance of the liquid-contacting parts of the casing. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the present invention provides a front casing for a slurry pump, which is used in a slurry pump in which a rubber casing liner is installed inside the casing, and which is arranged axially forward opposite a back casing that forms the rear part of the casing and is connected to the back casing by a plurality of bolt fastening parts, and which is manufactured from an aluminum alloy, and the axial front faces of the bolt fastening parts are formed by the same surface that is continuous with an annular rib arranged on the outer edge of the casing. [Effects of the Invention]

[0007] According to the present invention, since the front casing is made of an aluminum alloy, the maintenance workability of the liquid-contacting parts of the casing is improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an illustration of an embodiment of a slurry pump according to an aspect of the present invention, showing a cross section along the axis of the shaft. [Figure 2] 2A and 2B are explanatory views of the front casing of FIG. 1, in which FIG. 2A is a front view, FIG. 2B is a cross-sectional view taken along the line A, B, C, and D in FIG. 2A, FIG. 2C is a rear view, and FIG. 2D is a plan view showing the flange portion in FIG. [Figure 3] 2 is a perspective view illustrating the disassembly and assembly process of the front casing portion of FIG. 1. FIG. [Figure 4] FIG. 1 is an explanatory diagram of an example of a slurry pump equipped with a conventional front casing, showing a cross section along the axis of the shaft. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the drawings are schematic. Therefore, it should be noted that the relationship between thickness and planar dimensions, ratios, etc. differ from the actual ones, and the drawings also include portions where the relationship and ratio of dimensions differ from each other. Furthermore, the embodiments described below are intended to exemplify devices and methods for embodying the technical ideas of the present invention, and the technical ideas of the present invention do not limit the materials, shapes, structures, arrangements, etc. of the components to the embodiments described below.

[0010] As shown in FIG. 1, the slurry pump 100 of this embodiment includes a frame 8, a casing 1 provided in front of the frame 8, an impeller 2 supported on the tip of a shaft 3 protruding into the casing 1, and a gland packing 10 wrapped around the shaft 3 behind the impeller 2.

[0011] The casing 1 has a discharge port 1b formed at the top and a suction port 1a formed at the axial center, which protrudes forward along the axial direction. The casing 1 of this embodiment comprises a front casing 11 and a back casing 12, which are divided into front and rear halves near the axial center of the impeller 2. The back portion of the back casing 12 is fixed to the front surface of the frame 8 with bolts and nuts 13.

[0012] Furthermore, the front casing 11 and the back casing 12 are fixed to each other in the axial direction by casing bolts 14 and casing nuts 15 so as to sandwich the rubber casing liner 9, and an accommodation space for the impeller 2 is defined inside the casing liner 9. The casing liner 9 has a front liner 9a and a back liner 9b. The front liner 9a has a core and a rubber part covering the core, and a part of the core is a part where a fastener 16 to the front casing 11 is attached.

[0013] The base end side of the shaft (rotating shaft) 3 passes through the rear of the casing 1 and extends into the frame 8. A journal support 7 having two bearings 7a, 7b spaced apart in the axial direction is provided within the frame 8. The base end side of the shaft 3 is rotatably supported by this journal support 7. An output shaft of a motor is connected to the base end of the shaft 3 so as to transmit driving force.

[0014] The slurry pump 100 of this embodiment has a gland packing 10 that seals the tip end of the shaft 3, located at the center of the back surface of the back casing 12. The gland packing 10 is provided at the position of the shaft sleeve 4 between the back surface of the casing 1 and the above-mentioned bearing portion 7 of the shaft 3.

[0015] The gland packing 10 of this embodiment is disposed inside the stuffing box 50.

[0016] In the casing 1 of this embodiment, the back casing 12 is made of cast iron (FC200). In contrast, the front casing 11 is made of an aluminum alloy, and has a mass (e.g., 11 kg) that is approximately half the mass (e.g., 23 kg) of a front casing made of cast iron (FC200).

[0017] 2, in the front casing 11 of this embodiment, the three bolt mounting grooves 22 in the discharge side flange 21 extend in the same direction in consideration of ease of demolding. In this embodiment, the two left and right bolt mounting grooves 22 in the discharge side flange 21 are formed so that the groove extension direction, together with the central bolt mounting groove 22, opens forward along the axis of the shaft 3. In other words, the groove extension direction of the three bolt mounting grooves 22 in all three locations is the same as the axial direction of the casing 1.

[0018] In this case, if the outer shape of the discharge side flange 21 is a simple circular shape, pointed edges will stand around the outer end of the groove, making it impossible to secure a sufficient seating surface for the fastening bolts of the discharge side flange 21, and the pointed edges at the ends of the two bolt mounting grooves 22 on the left and right can also cause molding defects. Therefore, in the front casing 11 of this embodiment, the discharge side flange 21 has padding portions 23 around the outer ends of the two left and right bolt mounting grooves 22, each having an outer surface parallel to the groove extension direction.

[0019] Furthermore, in the front casing 11 of this embodiment, if it is simply made of an aluminum alloy, the pressure resistance will decrease. Therefore, in order to improve the pressure resistance performance, as shown in FIG. 2, an auxiliary bolt fastening portion 24 is provided as a fifth bolt fastening portion for an auxiliary bolt in the neck portion 25 of the discharge-side flange 21, separate from the four bolt fastening portions 18. In the slurry pump 100 of this embodiment, in other parts where the back casing 12 and the front casing 11 are made of different materials, an insulating sleeve is interposed along the axial direction at the four bolt fastening portions 18 of each casing bolt 14, and an insulating washer is interposed on the contact surface of each bolt fastening portion 18.

[0020] As shown in FIG. 4, in a conventional slurry pump 100 having a front casing 211 made of cast iron (FC200), a reinforcing rib 226 is provided around a neck portion 225 of a discharge side flange 221. In contrast, in slurry pump 100 of this embodiment, the neck portion 25 of discharge-side flange 21 can be shortened by employing the above-mentioned auxiliary bolts and thick-walled outer peripheral structure 27, thereby ensuring the strength of discharge-side flange 21 itself. Therefore, in this embodiment, as shown in Fig. 2, the reinforcing rib on neck portion 25 of discharge-side flange 21 is eliminated, improving the workability of installing bolts into bolt mounting grooves 22.

[0021] In addition, in the slurry pump 100 of this embodiment, the axial front faces of the four bolt fastening portions 18 are formed as the same surface that is continuous with the annular rib 40 arranged on the outer edge of the front casing 11 (the outer edge of the clamping surface 30 described later). The annular rib 40 is formed in a generally annular shape in the region indicated by annular hatching in Fig. 2(a) . Therefore, the annular rib 40 is formed in a region on the outer edge of the front casing 11 that is more inward than the four bolt fastening portions 18. Furthermore, in the slurry pump 100 of this embodiment, when an aluminum alloy front casing 11 is used, in order to make the front casing 11 as light as possible, a plurality of lightening portions 26 (26a to 26d) are formed around almost the entire circumference in the circumferential direction, as shown in FIG. 2, within the range where pressure resistance performance can be maintained. However, in consideration of pressure resistance, the axial thickness is a predetermined thickness to avoid molding defects, and in order to allow the multiple lightening portions 26 (26a to 26d) to function as gripping portions during attachment and detachment operations, the front surfaces of the four bolt fastening portions 18 are made flush with each other to form a thick structure.

[0022] Furthermore, in the slurry pump 100 of this embodiment, although the casing 1 is provided with a plurality of lightening portions 26 (26a to 26d) along the circumferential direction thereof, the four liner fastening portions 28 experience locally high stress due to fastening by the fasteners 16. Therefore, while an aluminum alloy front casing 11 is used, in order to secure the section modulus at key points, as shown in FIG. 2, a thick-walled liner fastening portion structure 29 is provided at the liner fastening portion 28 and its vicinity, in which the axial front side is formed into a trapezoidal convex shape and is thicker than other portions including the lightening portions 26 (26a to 26d).

[0023] Furthermore, in a casing structure that clamps a rubber casing liner 9 as in this embodiment, the slurry pump 100 of this embodiment has a clamping surface 30 that clamps the liner ear portion 9c of the front liner 9a that constitutes the casing liner 9 from the front and rear in the axial direction, and has multiple protrusions 31 (31a to 31d) that protrude axially toward the back side, as shown in the exploded oblique view of Figure 3.

[0024] As a result, in the slurry pump 100 of this embodiment, deformation of the liner ear portion 9c in the direction of expanding the diameter is more reliably suppressed, making it possible to ensure pressure resistance at key points even while using a front casing 11 made of aluminum alloy. Since the entire rubber casing liner 9 can distribute the surface pressure over the entire inner surface of the casing 1, as shown in Figure 2, the thickness of the conical surface 32 of the front casing 11 is made as thin as possible within the range where pressure resistance performance can be maintained. Furthermore, in the casing 1 of this embodiment, the front casing 11 is made of aluminum alloy, which makes it lighter than when the front casing is made of cast iron (compared to conventional casings). This makes it easier to increase the diameter and area of ​​the clamping surface 30, making it possible to suppress liquid leakage and improve pressure resistance.

[0025] Furthermore, in this type of slurry pump, as shown in Figure 3, during the assembly work of clamping the casing liner 9 from the front and rear in the axial direction, in order to maintain the housing position of the casing liner 9, it is necessary to tighten the casing bolts 14 and casing nuts 15 while pulling up the liner ear portions 9c. In contrast, in the slurry pump 100 of this embodiment, as shown in Fig. 2, a plurality of openings for lifting and holding the lifted portions 9d, 9e, and 9f (see Fig. 3) of the liner ear 9c are formed on the upper left and right sides in the direction of gravity between the plurality of protruding portions 31 (31a to 31d) on the clamping surface 30. As a result, the protruding portions 31b, 31c, and 31d form walls that are separated by the four bolt fastening portions 18 and that support the lifted portions 9d, 9e, and 9f of the liner ear 9c at three locations spaced apart in the circumferential direction.

[0026] As a result, according to the slurry pump 100 of this embodiment, the stored orientation of the casing liner 9 can be stably maintained on the lower side in the direction of gravity during assembly. Furthermore, when the pump is operating with the front casing 11 in the usage orientation, the protrusions 31b, 31c, and 31d that support the raised portions 9d, 9e, and 9f of the three liner ear portions 9c function as liner pressers and act as ribs that suppress deformation of the casing liner 9 in the radial direction, improving the support rigidity.

[0027] Next, the function and effect of the front casing 11 provided in the slurry pump 100 of this embodiment will be described. As described above, in the casing 1 of this embodiment, the front casing 11 is made of aluminum alloy, so the mass can be reduced to approximately half (e.g., 11 kg) compared to the mass (e.g., 23 kg) when made of cast iron. Therefore, when performing maintenance on the liquid-contacting parts, a single worker can remove the front casing 11 made of a relatively lightweight aluminum alloy to expose the liquid-contacting parts. Therefore, by employing the front casing 11 of this embodiment, the ease of maintenance of the liquid-contacting parts is improved.

[0028] However, in a structure in which different materials with different ionization tendencies are combined, such as the casing 1 of this embodiment, there is a problem that electrolytic corrosion may occur. In view of this point, this embodiment basically adopts a slurry pump from among various pumps. As a result, a rubber casing liner 9 is interposed at the joining surface of the cast iron (FC200) back casing 12 and the aluminum alloy front casing 11, so even though the structure is made of a combination of different materials, electrolytic corrosion at the joining surface itself is basically prevented or suppressed.

[0029] Furthermore, in the front casing 11, the axial front surfaces of the four bolt fastening portions 18 are formed as a single surface that is continuous with the annular rib 40. This makes it possible to suppress deformation over the entire circumference of the clamping surface 30, that is, the portion that clamps and presses the casing liner 9 [Invention 1]. In particular, in the front casing 11 of this embodiment, axially recessed lightening portions 26 (26a to 26d) are provided along the circumferential direction of the front casing 11, and the bolt fastening portion 18 and its vicinity are made thicker in the axial direction than other portions including the lightening portions 26 (26a to 26d). As a result, according to the front casing 11 of this embodiment, the hollowed-out portions 26 (26a to 26d) of the front casing 11 function as gripping portions during maintenance work on the liquid-contacting parts when the front casing 11 is attached or detached by a single worker, thereby further improving maintenance workability. Furthermore, at the four bolt fastening portions 18, stress becomes locally high due to bolt fastening. However, according to the front casing 11 of this embodiment, the bolt fastening portions 18 have a thicker structure than the lightening portions 26 (26a to 26d) (in particular, the surfaces of the bolt fastening portions 18 facing forward are flush), so even though an aluminum alloy front casing 11 is used, it has excellent formability and can secure a sufficient cross-sectional modulus at key points [Invention 2].

[0030] Furthermore, in the front casing 11 of this embodiment, the three bolt mounting grooves 22 in the discharge side flange 21 of the front casing 11 all extend in the same direction (the same direction as the axial direction of the casing 1), and the two bolt mounting grooves 22 on the left and right in the discharge side flange 21 extend in the same direction as the central bolt mounting groove 22, which makes it easier to demold the front casing 11 during production, further improving the productivity of the front casing 11 [Invention 3].

[0031] Furthermore, in the front casing 11 of this embodiment, a padding portion 23 having an outer surface parallel to the groove extension direction is provided around the outer ends of the two bolt mounting grooves 22 on the left and right sides of the discharge side flange 21. Therefore, when using a front casing 11 made of aluminum alloy, the bolt bearing surface is secured and formability is further improved [Invention 4].

[0032] Furthermore, in the slurry pump 100 of this embodiment, an auxiliary bolt fastening portion 24 is provided on the discharge side flange 21 of the front casing 11 for an auxiliary bolt, which is more suitable for maintaining or improving the pressure resistance performance while making the front casing 11 out of an aluminum alloy [Invention 5].

[0033] Conversely, in a conventional front casing made of cast iron (FC200), as shown in Figure 4, a reinforcing rib 226 was provided around the neck 225 of the discharge side flange 221. However, in the front casing 11 of this embodiment, as shown in Figure 1, the neck 25 of the discharge side flange 21 of the front casing 11 is provided with a thick outer surface structure 27, and in combination with the above-mentioned auxiliary bolt, it is possible to ensure the strength of the discharge side flange 21 itself. As a result, the neck 25 of the discharge side flange is configured without reinforcing ribs other than the auxiliary bolt fastening portion 24, so that reinforcing ribs can be eliminated and the workability of the bolt fastening operation is further improved [Invention 6].

[0034] Furthermore, in the front casing 11 of this embodiment, a protruding portion 31 that protrudes in the axial direction is provided on the back side of the clamping surface 30 that clamps the liner ear portion 9c of the rubber casing liner 9 from the front and rear in the axial direction. This more reliably suppresses deformation of the liner ear portion 9c in the direction in which the diameter expands, and ensures pressure resistance at key points even when using a front casing 11 made of aluminum alloy [Invention 7]. As for the entire casing liner 9, since the surface pressure can be distributed over the entire inner surface of the casing 1, the thickness of the front casing 11 can be made as thin as possible within the range where pressure resistance performance can be maintained.

[0035] Furthermore, in this type of slurry pump, during the assembly work of clamping the casing liner 9 from the front and rear in the axial direction, in order to maintain the storage position of the casing liner 9, it is necessary to tighten the casing bolt 14 and casing nut 15 of the bolt fastening portion 18 while pulling up the lifting portions 9d, 9e, and 9f of the liner ear portion 9c. In contrast, in the front casing 11 of this embodiment, as described above, openings for pulling up and holding the pulled-up portions 9d, 9e, and 9f of the liner ear 9c are formed on the left and right upper sides in the direction of gravity between the multiple protrusions 31 (31a to 31d). In addition, the protrusions 31b, 31c, and 31d form walls that are separated by the four bolt fastening portions 18 and that support the pulled-up portions 9d, 9e, and 9f of the liner ear 9c at three locations spaced apart in the circumferential direction.

[0036] As a result, according to the front casing 11 of this embodiment, the casing liner 9 can be stably maintained in a stored position at the lower side in the direction of gravity during assembly of the casing 1. Furthermore, when the slurry pump 100 is operating with the front casing 11 in a usage position, the three protrusions 31b, 31c, and 31d function as liner holders and act as ribs that suppress deformation of the casing liner 9 in the radial direction, thereby exhibiting the excellent effect of improving the support rigidity [Invention 8].

[0037] If it is possible to prevent or suppress electrolytic corrosion at the joints of different materials, the surfaces of the casing bolts 14 constituting each bolt fastening portion 18 can be subjected to a surface treatment including an electrolytic corrosion prevention function, and insulating washers can be interposed on the contact surfaces of each bolt fastening portion 18. Also, the surface of the front casing 11 can be subjected to a surface treatment including an electrolytic corrosion prevention function [Invention 9].

[0038] As described above, according to front casing 11 provided in slurry pump 100 of this embodiment, since front casing 11 is made of aluminum alloy, the maintenance workability of the liquid-contacting parts of casing 1 is improved. The front casing for a slurry pump according to the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0039] 1 casing 1a Intake port 1b Outlet 2 impellers 3 Shaft (rotating axis) 4 shaft sleeve 7 axis branches 8 frames 9 Casing liner 10 Gland packing 11 Front casing 12 Back casing 13 Bolts and nuts 14 Casing bolt (bolt fastening part) 15 Casing nut (bolt fastening part) 16 Fasteners 18 Bolt fastening part 21 Discharge flange 22 Bolt mounting groove 23 Meat Section 24 Auxiliary bolt fastening section 25 Neck 26 Cutout 27 Thick wall structure on outer circumference 28 Liner fastening part 29 Thick-walled structure of liner fastening part 30 Clamping surface 31 Overhang 32 Conical Surface 40 Annular rib 50 stuffing box 100 Slurry Pump

Claims

1. A front casing is used in a slurry pump in which a rubber casing liner is installed inside a casing, the front casing being disposed axially forwardly opposite a back casing that constitutes a rear portion of the casing and being connected to the back casing by a plurality of bolt fastening portions, It is made from aluminum alloy, A front casing for a slurry pump, characterized in that the axial front surface of the bolt fastening portion is formed as a surface continuous with and flush with an annular rib arranged on the outer edge of the casing.

2. a recessed portion is formed in the axial front surface along the circumferential direction of the casing; 2. The front casing for a slurry pump according to claim 1, wherein the bolt fastening portions are thicker in the axial direction than the recessed portions.

3. The discharge side flange of the front casing has bolt mounting grooves in three locations: the center and two on either side.

2. The front casing for a slurry pump according to claim 1, wherein the three bolt mounting grooves all extend in the same direction as the axial direction of the casing.

4. 4. A slurry pump front casing according to claim 3, wherein said discharge side flange is provided with padding portions having outer surfaces parallel to the extending direction of the grooves around the outer ends of the two bolt mounting grooves on the left and right.

5. 2. A front casing for a slurry pump according to claim 1, wherein said front casing has a discharge side flange, and an auxiliary bolt fastening portion for an auxiliary bolt is provided at a neck portion of said discharge side flange.

6. 6. The front casing for a slurry pump according to claim 5, wherein the neck portion of the discharge side flange does not have a reinforcing rib in a portion other than the portion where the auxiliary bolt is fastened.

7. 2. A front casing for a slurry pump according to claim 1, further comprising a clamping surface for clamping the liner ear portion of the casing liner together with the back casing from the front and rear in the axial direction, and a protruding portion extending in the axial direction is formed on the back side of the clamping surface.

8. 8. A front casing for a slurry pump as described in claim 7, wherein, when the front casing is in an in-use position, openings are formed on the left and right upper sides of the protrusion in the direction of gravity for pulling up and holding the liner ear portions of the casing liner.

9. 2. The front casing for a slurry pump according to claim 1, wherein the surface of said front casing is subjected to a surface treatment including a function of preventing electrolytic corrosion.

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