JP7484691B2 - Seal insertion tool for slurry pumps - Google Patents

Description

The present invention relates to a seal insertion jig for a slurry pump, and in particular to a seal insertion jig used when replacing an oil seal used in the shaft seal of a centrifugal slurry pump.

In wet non-ferrous metal smelting plants, pulp and paper plants, waste treatment plants, and the like, a fluid called a slurry, which contains powdery solids suspended in a liquid, is generally used as the processing liquid, and a centrifugal slurry pump called a Warman Pump (registered trademark), as disclosed in Patent Document 1, is often used to transport this slurry. A centrifugal slurry pump is a rotary machine that rotates an impeller (also called an impeller or centrifugal blade) inside a casing equipped with a slurry intake and discharge port, and uses the centrifugal force generated by this to pressurize the slurry and transport it.

The above-mentioned slurry pump is susceptible to wear at the liquid-contacting parts due to the solids contained in the pumped slurry, so a replaceable liner made of metal casting or rubber molding is attached to the inside of the casing made of cast iron or the like that houses the impeller. This liner can be divided into at least two parts, the front side and the back side when viewed from the suction side of the casing, so that it can be easily replaced when wear-induced thinning progresses, and the suction side of the casing can also be removed when replacing the liner.

In centrifugal slurry pumps like the one above, the drive shaft that rotates the impeller passes through the casing and is connected to a driving means such as a motor, and in order to improve the sealing of this passing part, an impeller with a smaller diameter than the impeller, called an expeller, may be attached coaxially to the drive shaft on the back side of the impeller. The centrifugal force of this expeller prevents the slurry from entering the shaft seal from the casing.

In addition, while a typical centrifugal pump often uses a gland packing or mechanical seal as an annular sealing member in the shaft seal, the above-mentioned slurry pump often uses an oil seal consisting of a lip portion that slides against the drive shaft, a metallic annular portion that holds the lip portion, and a spring portion that presses the lip portion against the drive shaft.

JP 2019-007404 A

By providing an expeller behind the impeller as described above, it becomes difficult for slurry to penetrate the shaft seal of the drive shaft that passes through the casing in which the impeller is housed, making it possible to pump the slurry stably for a long period of time. However, when a slurry pump is operated continuously for a long period of time, leakage may occur in the oil seal, which is a consumable item. In this case, it is necessary to stop the operation of the slurry pump and replace the oil seal with a new one.

This replacement work requires that a new oil seal be correctly attached to the shaft seal, and so traditionally this required skilled techniques. That is, in types without an expeller, the oil seal must be inserted accurately and without tilting into the designated position of the packing box (also called a stuffing box) into which the oil seal is fitted, while in types with an expeller, the oil seal must be inserted accurately and without tilting into the designated position of the expeller ring into which the oil seal is fitted.

If the above work is not done properly, the oil seal may continue to leak even after it has been replaced with a new one, or the seal surface may be damaged. The present invention was made in consideration of the above problems, and aims to provide a seal insertion tool that allows even non-experts to easily and correctly replace the seal member of the shaft seal of a slurry pump.

In order to achieve the above object, the seal insertion jig for a slurry pump according to the present invention is a metal seal insertion jig used when replacing the seal member of the shaft seal of a slurry pump, and is made of a rod-shaped member having a first flange and a second flange with different outer diameters at both ends, and the first flange and the second flange are each provided with a first step portion in the shape of an expanded rod-shaped member on the surface opposite to the surfaces facing each other, and a second step portion that is concentric with the second flange and protrudes in a flat annular shape with a flat top, and the outer diameters of the first step portion and the second step portion are different from each other and are also different from the outer diameters of the first flange and the second flange.

According to the present invention, even an unskilled technician can easily and correctly replace the seal member of the shaft seal of a slurry pump, such as a Warman pump.

FIG. 1 is an enlarged longitudinal cross-sectional view of a main portion of a typical slurry pump equipped with an expeller, which is the subject of the seal insertion jig of the present invention, taken along a plane including the center line of the shaft. 1 is an enlarged longitudinal cross-sectional view of a main portion of a typical expeller-less slurry pump, which is the subject of the seal insertion jig of the present invention, taken along a plane including the central axis of the shaft. 1 is a longitudinal sectional view of a seal insertion jig according to an embodiment of the present invention, taken along a plane including a central axis thereof. FIG. 4 is a perspective view of the seal insertion jig of FIG. 3 as viewed from the second flange side. 4 is a perspective view of the seal insertion jig of FIG. 3 when turned upside down and viewed from the first flange side. FIG. FIG. 4 is a cross-sectional view showing a process of fitting a new oil seal into an expeller ring of a slurry pump using the seal insertion jig of FIG.

First, a Warman pump will be described as a specific example of a slurry pump for which the seal insertion tool of the present invention is intended. Warman pumps are available with and without an expeller, and FIG. 1 shows an enlarged longitudinal cross-sectional view of a Warman pump with an expeller along with its shaft seal. That is, the Warman pump 10 shown in FIG. 1 is a centrifugal pump that pressurizes the slurry introduced from the suction port by centrifugal force generated by the rotation of the impeller and discharges it from the discharge port, as indicated by the white arrow, and the impeller is rotated by a driving means such as an electric motor (motor) not shown.

Specifically, the Warman pump 10 shown in FIG. 1 has a casing 13 made up of a frame plate 11 fixed on a pump stand (not shown) and a cover plate 12 fastened to the frame plate 11 with bolts and nuts, and an impeller 15 attached to the tip of a drive shaft (main shaft) 14 that rotates by the rotational driving force of the drive means is housed in the casing 13. The slurry pumped by the rotation of the impeller 15 is an abrasive fluid containing fine powder particles, so the impeller 15 is made of a material with excellent abrasion resistance. Furthermore, to prevent the casing 13 from being worn down by the slurry, a frame plate liner 16 and a cover plate liner (also called a volute liner) 17 are detachably attached to the frame plate 11 and cover plate 12, respectively, as linings.

The drive shaft 14 to which the impeller 15 is attached has an expeller 18 attached to the inner space separated by the frame plate liner 16. The expeller 18 rotates simultaneously with the impeller 15 by the drive shaft 14, generating centrifugal force on the slurry that has entered the space in which the expeller 18 is housed. This presses the slurry radially outward in the space in which the expeller 18 is housed, preventing the slurry from entering the shaft seal portion described below. Note that while the pump is stopped, the sealing function of the expeller 18 stops, so a shaft seal portion described below is provided to complement this.

A shaft sleeve 19 is fitted onto the outer periphery of the drive shaft 14, which allows the outer periphery to slide against a sealing member such as an oil seal, which will be described later. In other words, the drive shaft 14, which is rotatably supported by bearings such as two sets of tapered roller bearings (not shown), will wear out due to sliding contact with the sealing member if left as is. Therefore, to prevent damage due to wear of the sealing member, a roughly cylindrical shaft sleeve (also called a packing sleeve) 19 that rotates integrally with the drive shaft 14 is fitted onto the outside.

The shaft seal section 20 located at the rear of the expeller 18 partially constitutes the wall that defines the space in which the expeller 18 is housed, and is composed of an expeller ring 21 that acts as a housing into which an oil seal, described later, is fitted, an oil seal 22 that prevents the slurry from leaking from the casing 13, and a lantern ring 23 that distributes the high-pressure water injected into the expeller ring 21 to improve sealing performance.

To explain each of the components constituting the shaft seal section 20 in detail, the expeller ring 21 is composed of a generally cylindrical tubular section with one end bent inward, and a generally funnel-shaped flange section that is concentrically arranged on the outer circumferential surface of the one end side of the tubular section and partially constitutes a wall section that defines the space in which the expeller 18 is housed, and multiple oil seals 22 are concentrically fitted inside the tubular section. A through hole is provided in the tubular section of the expeller ring 21, and a lantern ring 23 with multiple seal water distribution ports is fitted in a position that blocks the through hole. When inserting multiple oil seals 22 inside the tubular section of the expeller ring 21, a seal insertion tool for a slurry pump according to an embodiment of the present invention described later is used.

The oil seal 22 fitted inside the cylindrical portion of the expeller ring 21 is available in various shapes and materials, and is selected appropriately depending on the properties and conditions of the slurry to be pumped. A typical shape is a flexible member with a roughly C-shaped cross section, and the side of the flexible member that slides against the shaft sleeve 19 is called the lip portion. To press this lip portion against the shaft sleeve 19, an annular spring may be attached near the tip of the lip portion as necessary. Also, a metal ring with a roughly L-shaped cross section may be provided on the flexible member on the cylindrical portion side of the expeller ring 21.

When replacing the oil seal 22 of the Warman pump 10 equipped with the expeller 18 of the above structure with a new one, it is necessary to stop the operation of the pump, disconnect the suction side piping (not shown) from the casing 13, and then disassemble the Warman pump 10. When disassembling the Warman pump 10, the cover plate 12, cover plate liner 17, impeller 15, frame plate liner 16, expeller 18, and shaft seal 20 are generally removed in this order from the right side of the paper in FIG. 1. Note that, depending on the model, it may be necessary to remove the frame plate 11 before removing the shaft seal 20. The shaft seal 20 removed as described above is replaced with a new oil seal 22 using a seal insertion tool for a slurry pump according to an embodiment of the present invention, as described later. After the replacement, the Warman pump 10 can be restored by reassembling in the reverse order to the above.

Next, as another specific example of a slurry pump targeted by the slurry pump seal insertion tool of the present invention, a Warman pump 110 without an expeller as shown in FIG. 2 will be described. Like the Warman pump shown in FIG. 1, the Warman pump 110 shown in FIG. 2 also has a casing 113 composed of a frame plate 111 fixed to a pump stand (not shown) and a cover plate 112 fastened to the frame plate 111 by bolts and nuts, and an impeller 115 attached to the tip of a drive shaft 114 is housed in the casing 113. In addition, a frame plate liner 116 and a cover plate liner (also called a volute liner) 117 are detachably attached as linings of the frame plate 111 and the cover plate 112, respectively.

The Warman pump 110 shown in FIG. 2 differs from the Warman pump 10 in FIG. 1 in that it does not have an expeller at the rear of the frame plate liner 116, but has a shaft seal 120 directly thereon. Therefore, unlike the shaft seal 20 in FIG. 1, the shaft seal 120 in FIG. 2 uses a packing box 121 instead of an expeller ring in the housing that contains the oil seal and lantern ring.

Specifically, the packing box 121 shown in FIG. 2 is composed of a generally cylindrical tubular portion into which multiple oil seals 122 are concentrically fitted, and an annular flange portion provided at one end of the tubular portion, with the peripheral edge of the flange portion engaging with a stepped portion of the frame plate 111. The tubular portion of the packing box 121 has a through hole, similar to the expeller ring 21 described above, and a lantern ring 123 is fitted in a position that blocks this through hole. When inserting multiple oil seals 122 into the inside of the tubular portion of the packing box 121, a seal insertion jig according to an embodiment of the present invention described below is also used.

When replacing the oil seal 122 of the Warman pump 110 without an expeller having the above-mentioned structure with a new one, the procedure is basically the same as that of the Warman pump 10 with the expeller 18 in FIG. 1, except for the expeller 18. After stopping the pump and disconnecting the suction side piping from the casing 113, the cover plate 112, cover plate liner 117, impeller 115, frame plate liner 116, and shaft seal 120 are removed in this order from the right side of the paper in FIG. 2. The shaft seal 120 thus removed is replaced with a new oil seal 122 using a seal insertion tool for a slurry pump according to an embodiment of the present invention, as described below. After replacement, the Warman pump 110 can be restored by reassembling in the reverse order to that described above.

Next, a seal insertion jig for a slurry pump according to an embodiment of the present invention, which is used when replacing the oil seals 22, 122 of the shaft seals 20, 120 of the Warman pump 10 equipped with the expeller 18 or the Warman pump 110 without an expeller with new ones, and a seal insertion method using this seal insertion jig will be described. The seal insertion jig for a slurry pump according to an embodiment of the present invention is an integral part that can be suitably manufactured by casting or cutting out a metal such as steel, and as shown in the cross-sectional view of FIG. 3, a first flange 2 and a second flange 3, each of which is brim-shaped and has a thickness of about 12 to 18 mm, are provided concentrically with the rod-shaped member 1 at both ends of the rod-shaped member 1. In the seal insertion jig according to an embodiment of the present invention, the outer diameter D ₀ of the rod-shaped member 1 is preferably about 20 to 40 mm, and the total length L ₁ is preferably about 150 to 250 mm, so that the worker can easily hold it with one hand when replacing a seal member such as an oil seal.

Furthermore, the first flange 2 and the second flange 3 are provided with a first step 4 in a shape in which the rod-shaped member 1 is expanded in diameter, and a second step 5 which is concentric with the second flange 3 and protrudes in a flat annular shape with a flat top, in an area other than the peripheral edge on the surface opposite to the surfaces facing each other. The outer diameter _D1 of the first flange 2 and the outer diameter _D2 of the second flange 3 are different from each other. The outer diameter _D3 of the first step 4 and the outer diameter D4 of the second step ₅ are different from each other, and the outer diameter _D3 of the first step 4 and the outer diameter D4 of the second step ₅ are also different from the outer diameter _D1 of the first flange 2 and the outer diameter _D2 of the second flange 3.

By using the jig with the above structure, an oil seal can be inserted using the peripheral portion of the first flange 2 or the peripheral portion of the second flange 3, or the top of the first step portion 4 or the top of the second step portion 5. In other words, the seal insertion jig for a slurry pump according to the embodiment of the present invention can handle four different sizes of oil seals by appropriately using the peripheral portions and step portions on the opposite sides of the first flange 2 and the second flange 3 from the opposing sides.

For example, by setting the outer diameter _D0 of the cylindrical rod member 1 to 30 mm, the outer diameter D1 of the first flange portion ₂ to 75 mm, the outer diameter D2 of the second flange portion ₃ to 88 mm, the outer diameter D3 of the first step portion ₄ to 42 mm, the outer diameter D4 _of the second step portion ₅ to 68 mm, and the inner diameter _D5 to 50 mm, it becomes possible to accurately press the corresponding oil seal into a predetermined position inside the expeller ring or packing box of a Warman pump having an inner diameter slightly larger than these outer diameters D1 to _D4 , without requiring any particular skill, so as not to tilt its central axis, regardless of the presence or absence of an expeller.

That is, by using the peripheral portion 2a of the surface opposite to the surface facing the second flange 3 in the first flange 2, an oil seal can be inserted into an expeller ring or packing box for a pump size of "4-3SC". Also, by using the top portion 4a of the first step portion 4 of the first flange 2, an oil seal can be inserted into an expeller ring or packing box for a pump size of "1-3/4SC". Also, by using the peripheral portion 3a of the surface opposite to the surface facing the first flange 2 in the second flange 3, an oil seal can be inserted into an expeller ring or packing box for a pump size of "6-4SC". Also, by using the top portion 5a of the second step portion 5 of the second flange 3, an oil seal can be inserted into an expeller ring or packing box for a pump size of "3-2SC".

When inserting an oil seal using the peripheral portion 2a of the first flange 2 or the top portion 4a of the first step portion 4, the oil seal can be inserted efficiently by lightly striking the second end face 1b on the side of the rod-shaped member 1 opposite the side where the first flange 2 is located with a rubber hammer or the like multiple times. Similarly, when inserting an oil seal using the peripheral portion 3a of the second flange 3 or the top portion 5a of the second step portion 5, the oil seal can be inserted efficiently by lightly striking the first end face 1a on the side of the rod-shaped member 1 opposite the side where the second flange 3 is located with a rubber hammer or the like multiple times.

The distance H ₁ between the first end face 1a of the rod-shaped member 1 and the peripheral edge 2a of the first flange ₂ , and the distance H 2 between the second end face 1b and the peripheral edge 3a of the second flange 3, are each preferably about 20 to 40 mm. The distance H ₃ between the first end face 1a and the top 4a of the first step portion 4, and the distance H ₄ between the second end face 1b and the top 5a of the second step portion 5 are each preferably about 15 to 25 mm.

The seal insertion jig for a slurry pump according to the embodiment of the present invention is provided with a substantially cylindrical striking part 6 protruding about 3 to 8 mm in a direction perpendicular to the central axis O- ₁ at the center of the rod-shaped member 1 in the direction of the central axis O- ₁ . As a result, when an oil seal is inserted into an expeller ring or a packing box placed on a flat table with its open end facing directly upward as described later, the middle part of the rod-shaped member 1 between the first flange part 2 and the second flange part 3 and the side opposite to the side from which the striking part 6 protrudes is brought into contact with the oil seal placed on or partially inserted into the open end of the expeller ring or packing box from directly above, and the top part 6a of the striking part 6 is lightly struck with a rubber hammer or the like, so that the end of the oil seal and the open end of the expeller ring or packing box are in a so-called flush state. The outer diameter of the striking part 6 is preferably about the same as the outer diameter of the rod-shaped member 1.

In order to insert the oil seal more stably into the expeller ring or packing box when the top 6a of the striking portion 6 is struck with a rubber hammer or the like, the rod-shaped member 1 is preferably provided with a flat surface 7 perpendicular to the protruding direction of the striking portion 6 and extending in the direction of the central axis _O1 of the rod-shaped member 1, between the first flange 2 and the second flange 3 and on the side opposite to the striking portion 6. The distance _L2 over which the flat surface 7 extends in the direction of the central axis O1 of the rod-shaped member ₁ is preferably longer than the largest outer diameter of the four types of oil seals handled by the seal insertion jig, and is preferably about 90 to 150 mm, for example. The width W of the flat surface 7 is preferably about 10 to 20 mm.

Next, a method for replacing an oil seal in a shaft seal portion of a slurry pump using the seal insertion tool for a slurry pump according to the embodiment of the present invention will be described using an expeller-equipped Warman pump (type 4-3SC) as an example. Note that in a type 4-3SC Warman pump, the outer diameter of the oil seal 22 and the inner diameter of the expeller ring are both 76.5 mm, so the peripheral portion 2a of the first flange 2, which has an outer diameter _D1 of 75 mm as shown in Figure 3, is used to insert the oil seal 22. Below, the steps will be described with reference to Figure 6, which shows the order of steps.

First, remove the shaft seal 20 from a Warman pump as shown in Figure 1 following the disassembly procedure described above, and remove the multiple oil seals 22 and lantern ring 23 that are fitted inside the cylindrical part of the expeller ring 21 that constitutes the shaft seal 20. Then, as shown in Figure 6(a), place the expeller ring 21 from which the oil seals etc. have been removed on a flat table with its funnel-shaped flange facing downward. In this state, place the first new oil seal 22 on the upper open end of the cylindrical part of the expeller ring 21 and lightly press it in by hand. At this time, be careful not to make a mistake with the orientation of the oil seal 22.

Next, as shown in FIG. 6(b), the rod-shaped member 1 is held vertically with one hand so that the first end face 1a on the side of the first flange 2 of the slurry pump seal insertion jig faces straight down, and the peripheral edge portion 2a of the first flange 2 is brought into concentric contact with the oil seal 22. In this state, the second end face 1b opposite to the first end face 1a is lightly struck multiple times, preferably with a rubber hammer G. In this way, the entire peripheral edge portion 2a of the first flange 2 is pressed uniformly against the oil seal 22 in the circumferential direction, so that the oil seal 22 can be pushed into the inside of the cylindrical portion of the expeller ring 21 without tilting it.

Next, as shown in FIG. 6(c), after the first oil seal 22 has been inserted, the second oil seal 22 is placed on the upper open end of the cylindrical portion of the expeller ring 21 in the same manner as the first oil seal 22 and lightly pressed in by hand. Then, as shown in FIG. 6(d), the peripheral portion 2a of the first flange 2 of the seal insertion jig is brought into concentric contact with the second oil seal 22, and the second end surface 1b is lightly struck multiple times, preferably with a rubber hammer G.

When inserting three or more oil seals into the cylindrical portion of the expeller ring 21, the above steps in Figs. 6(c) and (d) can be repeated. When inserting the lantern ring 23 after inserting the oil seal 22, the oil seal 22 is pushed deeper than the through hole in the cylindrical portion of the expeller ring 21 that communicates with the lantern ring 23 so that the through hole is not blocked by the oil seal 22. The lantern ring 23 may be the one removed when disassembling the shaft seal portion 20 and reused.

When inserting the oil seal 22, if it is necessary to align the end of the oil seal 22 with the upper open end of the cylindrical part of the expeller ring 21 to achieve the above-mentioned flush state, hold the rod-shaped member 1 of the seal insertion jig horizontally with one hand as shown in Figure 6 (e), and bring the flat surface 7 between the first flange 2 and the second flange 3 of the rod-shaped member 1 into contact with the oil seal 22, and in this state, lightly strike the top 6a of the striking part 6 opposite the flat surface 7 several times, preferably with a rubber hammer G.

After replacing the oil seal 22 of the shaft seal portion 20 with a new one as described above, the shaft seal portion 20 is fitted onto the tip side of the drive shaft 14 and installed on the specified outer peripheral surface of the shaft sleeve 19, and the expeller 18, frame plate liner 16, impeller 15, cover plate liner 17, and cover plate 12 are attached in this order as described above, thereby restoring the Warman pump. The seal members can also be replaced in the same manner as above for other Warman pumps other than the above type 4-3SC. The seal members in the packing box can also be replaced in the same manner as above for Warman pumps without expellers.

The above describes an embodiment of the seal insertion tool for a slurry pump and a seal replacement method using the same, but the present invention is not limited to the above embodiment and can include various modifications and alternative examples within the scope of the present invention. For example, in the above embodiment, the seal insertion tool is used to replace the oil seal of a Warman pump, but the present invention is not limited to this and can also be used to replace other types of seal members such as gland packings. It can also be used to replace seal members of slurry pumps other than Warman pumps.

LIST OF SYMBOLS 1 Rod-shaped member 1a First end surface 1b Second end surface 2 First flange 3 Second flange 2a, 3a Peripheral edge 4 First step 5 Second step 6 Impact portion 4a, 5a, 6a Top 7 Flat surface 0 ₁ Central axis 10, 110 Warman pump 11, 111 Frame plate 12, 112 Cover plate 13, 113 Casing 14, 114 Shaft 15, 115 Impeller 16, 116 Frame plate liner 17, 117 Cover plate liner 18 Expeller 19, 119 Shaft sleeve 20, 120 Shaft seal portion 21 Expeller ring 121 Packing box 22, 122 Oil seal 23, 123 Lantern ring

Claims (3)

A metal seal insertion jig used when replacing the seal member of the shaft seal of a slurry pump, the seal insertion jig for a slurry pump is characterized in that it is made of a rod-shaped member having a first flange and a second flange with different outer diameters at both ends, and the first flange and the second flange are each provided with a first step portion in the shape of an expanded rod-shaped member on the surface opposite to the surfaces facing each other, and a second step portion that is concentric with the second flange and protrudes in a flat annular shape with a flat top, and the outer diameter of the first step portion and the second step portion are different from each other and also different from the outer diameter of the first flange and the outer diameter of the second flange. The seal insertion jig for a slurry pump according to claim 1, characterized in that a striking part protruding in a direction perpendicular to the central axis is provided at the center of the central axis direction of the rod-shaped member. The seal insertion jig for a slurry pump according to claim 2, characterized in that a flat surface perpendicular to the protruding direction of the striking portion is provided in the rod-shaped member between the first flange and the second flange and on the opposite side to the portion where the striking portion is provided, so as to extend in the central axis direction of the rod-shaped member.

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