JP2025025256A - Fluid device and method for adjusting gap in fluid device - Google Patents

Abstract

To adjust a minimum clearance interval between an impeller and a liner ring which are worn by a long-time use, in a fluid apparatus.SOLUTION: A fluid apparatus comprises: an impeller 20 for imparting pressure to fluid by rotation; a casing 2 having a flow passage which guides fluid boosted by the impeller 20 in a discharge direction; and a liner ring 31 inserted into an attachment part 56 of the casing, and opposing the impeller 20 with a clearance d. Inclination faces 31b, 22 are formed in opposing portions of the liner ring 31 and the impeller 20, respectively. Also, a spacer 32 is arranged between the liner ring 31 and the attachment part 56, and a size of the clearance d between the inclination faces 31b, 22 can be adjusted by a thickness of the spacer 32.SELECTED DRAWING: Figure 6

Description

The present invention relates to a fluid device that allows the gap between an impeller and a liner ring to be adjusted, and a method for adjusting the gap.

In today's society, where measures to combat environmental issues such as global warming are urgently needed, manufacturing that takes into consideration not only simple product quality but also environmental aspects is required. In the pump industry, it was common to discard old pumps and replace them with new ones, but considering the impact on the environment, a method has been devised to repair and reuse old pumps. To reuse old pumps, the appearance and performance must be brought to the same standard as new ones. However, the impeller, which is particularly important for performance, wears down the opposing parts of the liner ring and the impeller after many years of use, widening the gap, and it is often the case that the performance at the time of manufacture cannot be guaranteed. Regarding the gap between the liner ring and the impeller, Patent Document 1 discloses a technology that adjusts the gap by moving the impeller along with the bearing part.

JP 2019-210869 A

In the technology of Patent Document 1, the gap is adjusted by moving the impeller of the fluid equipment in the direction of the rotation axis so that it approaches the liner ring. With this method, the impeller is moved along with the bearing part, so for example the ball bearing is adjusted by being compressed by being sandwiched between the main shaft and the casing cover, which places extra load on the mechanism parts other than the gap area, which may result in a shortened product life. In consideration of the environmental impact, it is preferable for each part to be able to be used repeatedly for a long time.

The present invention has been made in consideration of the above-mentioned background, and its object is to provide a fluid equipment that can adjust the gap between a liner ring and an impeller without placing extra load on mechanical parts other than the parts that form the gap, and a method for adjusting the gap.
Another object of the present invention is to provide a fluid equipment and a gap adjustment method thereof in which the gap can be easily adjusted even if the liner ring and its opposing part are worn, by improving the shape of the liner ring and the shape of the impeller facing the liner ring.

Representative features of the invention disclosed in this application are as follows.
According to one feature of the present invention, the fluid device includes a main shaft rotated by a drive source, an impeller that applies pressure to a fluid from near the axis toward the outside in the radial direction by rotating while being fixed to the main shaft, a casing that houses the impeller and has a fluid inlet and outlet and a flow path that guides the fluid pressurized by the impeller toward the outlet, and a cylindrical liner ring in a mouth section of the casing that faces the impeller with a gap, the liner ring having a first inclined surface that inclines in a direction intersecting with the rotation axis of the impeller on the casing side of the mouth section that faces the impeller with a minimum gap. The liner ring is inserted into the casing on the inner wall side of the casing toward the rotation axis and is arranged to face the impeller with a gap. In addition, a spacer is interposed between the mounting section of the liner ring in the casing and the liner ring to adjust the size of the gap between the first inclined surface and the impeller. A second inclined surface is formed parallel to the first inclined surface at a portion of the impeller facing the liner ring. The first inclined surface and the second inclined surface are inclined in a direction intersecting the direction of the rotation axis.

According to another feature of the present invention, a plurality of annular spacers having different lengths in the direction of the rotation axis are prepared, and one of them is placed between the mounting portion and the liner ring to adjust the distance in the direction of the rotation axis between the mounting portion and the liner ring. Also, a plurality of annular spacers of the same size are prepared, and the necessary number of spacers are placed between the mounting portion and the liner ring to adjust the distance between the first inclined surface and the second inclined surface. It is preferable that the angle formed by the first inclined surface with respect to the axis of rotation is greater than 0 degrees and less than 45 degrees. In addition, by forming a non-through hole recessed in a direction perpendicular to the second inclined surface in a part of the circumferential direction of the second inclined surface of the impeller, the amount of wear on the surface of the impeller can be measured by measuring the depth of the non-through hole after many years of use of the fluid device. Furthermore, the second inclined surface of the impeller may be formed in a stepped shape with multiple inclined surfaces each parallel to the first inclined surface. Each of the multiple inclined surfaces and the first inclined surface are parallel to each other, but the distance between the first inclined surface and the first inclined surface is different.

According to yet another feature of the present invention, when the casing is disassembled during disassembly and maintenance of the fluid equipment, the amount of wear on the second inclined surface of the impeller is measured, and the mounting position of the liner ring is adjusted so that it is moved closer to the impeller and then fixed according to the measured amount of wear. This adjustment is performed by interposing a spacer of a specified thickness between the liner ring and the mounting part of the casing. The amount of wear can be calculated by measuring the diameter of the innermost position of the second inclined surface of the impeller and comparing it with the value at the manufacturing stage or the design value. In addition, if the second inclined surface is formed as a multi-stage inclined surface, the amount of wear on the impeller during the gap adjustment can be determined by comparing the number of remaining steps on the inclined surface of the impeller with the number of steps at the initial manufacturing stage, and by the size of each step and the number of steps that have disappeared due to wear.

According to the present invention, the amount of wear on the impeller and liner ring can be easily measured during disassembly and maintenance of fluid equipment, and the provision of a spacer makes it possible to appropriately adjust the gap between the liner ring and the impeller. Furthermore, since this adjustment does not involve movement of the impeller in the direction of the rotation axis Ax, the gap between the liner ring and the impeller can be appropriately adjusted without placing a burden on other parts (particularly the bearings and shaft seals) other than the minimum gap part or on other components.

1 is a perspective view showing the appearance of a centrifugal pump 1 according to an embodiment of the present invention. FIG. 1 is an exploded perspective view of a conventional centrifugal pump 101. 1 is a vertical cross-sectional view passing through a rotation axis Ax of a conventional centrifugal pump 101. FIG. 1 is a partial cross-sectional view showing the state of an impeller 120' and a liner ring 131' of a conventional centrifugal pump 101 after long-term use. 1 is a vertical sectional view passing through a rotation axis Ax of a centrifugal pump 1 according to an embodiment of the present invention. 5A is an enlarged view of the mouth portion C in FIG. 5, and FIG. 5A to 5C are diagrams illustrating a procedure for adjusting the clearance of the centrifugal pump 1 according to the present embodiment. 1A to 1C are diagrams illustrating an example of a method for measuring the gap of the mouth portion C of the centrifugal pump 1 according to the present embodiment. 1A is an enlarged view of a mouse portion C according to a first embodiment, and FIG. 1B is an enlarged view of a mouse portion C according to a second embodiment. 11 is an enlarged view of a mouth portion C of a fluid device 1A according to a third embodiment of the present invention. FIG. 13 is an enlarged view of a mouth portion C of a fluid device 1B according to a fourth embodiment of the present invention. FIG. 13 is an enlarged view of a mouth portion C of a fluid device 1C according to a fifth embodiment of the present invention. FIG.

Below, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a centrifugal pump called a single-suction single-stage volute pump will be described as an example of fluid equipment. However, the present invention is not limited to centrifugal pumps, and can be applied to all fluid equipment that uses impellers. Each of the following figures shows the present invention in a schematic manner to allow a sufficient understanding of the present invention. Therefore, the present invention is not limited to only the examples shown in the figures, and can be combined as appropriate. In addition, in each figure, common or similar components are given the same reference numerals, and duplicate explanations of them will be omitted.

1 is a perspective view of a fluid device (centrifugal pump 1) according to an embodiment of the present invention. In this embodiment, the fluid device is assumed to be a centrifugal pump 1. The centrifugal pump 1 is configured as a single-suction single-stage volute pump, and a centrifugal space is formed by a volute casing 2 and a casing cover 40. The centrifugal space is a space for pressurizing the liquid sucked in by an impeller (described later) to increase the flow rate and discharge it. The volute casing 2 is provided with a suction port 5 that sucks in the fluid from the front to the rear in the direction of the rotation axis Ax, and a discharge port 6 that discharges the fluid in a direction perpendicular to the direction of the rotation axis Ax, here upward. A mounting flange 51 is provided around the suction port 5, and external piping (not shown) is connected by bolting using four bolt holes formed in the flange 51. Similarly, a mounting flange 61 is provided around the discharge port 6, and external piping (not shown) is connected by bolting using four bolt holes formed in the flange 61. The liquid handled by the centrifugal pump 1 in this embodiment is primarily assumed to be clean water, but other liquids may also be used.

The rear side of the spiral casing 2 is closed by a casing cover 40. On the outer edge of the rear opening of the spiral casing 2, multiple screw bosses 3 for screw holes are formed. In addition, multiple screw bosses 41 for through holes for passing screws or bolts (not shown) are formed around the outer periphery of the casing cover 40. A through hole (not visible in FIG. 1) for passing the main shaft 7 is formed on the rear side of the casing cover 40, and a bearing part 8 for rotatably supporting the main shaft 7 is provided coaxially with the through hole. A leg part 4 is connected to the underside of the spiral casing 2. The leg part 4 is a fixing device for bolting the centrifugal pump 1 to a floor, a pedestal, etc., and multiple through holes 4a for passing screws or bolts (not shown) are formed.

The centrifugal space contains a main shaft 7 arranged to pass through the spiral casing 2, and an impeller 20 (see FIG. 5 described later) fixed to the main shaft 7 so as to be rotatable integrally. The main shaft 7 extends rearward from inside the spiral casing 2, passing through the bearing 8. A drive source (not shown) is connected to the main shaft 7, which extends rearward beyond the bearing 8, and rotates the impeller 20 (see FIG. 5 described later). This drive source is, for example, a motor, but the drive source of the fluid device of this embodiment is not limited to a motor, and various known power sources such as engines, water wheels, and windmills can be used as long as they are devices that can supply rotational force to the main shaft 7.

Figure 2 is an exploded perspective view of a conventional centrifugal pump 101. The only differences between the conventional centrifugal pump 101 and the centrifugal pump 1 of this embodiment shown in Figure 1 are the shape of the liner ring 131, the shape of part of the impeller 120, and the shape of the vicinity of the attachment portion of the liner ring 131 in the volute casing 2. Other than that, the centrifugal pump 1 of this embodiment shown in Figure 1 can be manufactured using the same parts as the conventional centrifugal pump 101. Therefore, the centrifugal pump 1 of this embodiment and the conventional centrifugal pump 101 shown in Figures 2 to 4 have the same shape as seen from the outside.

A flow path for fluid flow is provided inside the spiral casing 2, and a circular opening 2a is formed on the rear side for inserting the impeller 120. The opening 2a is closed by a casing cover 40. A cylindrical liner ring 131 is provided on the inner wall of the spiral casing 2, which is adjacent to and faces the cylindrical portion 121 of the impeller 120. The liner ring 131 is inserted into the spiral casing 2 from the rear side toward the front side in the direction of the rotation axis Ax.

The main shaft 7 is a one-piece molded metal member that is long in the front-rear direction, and is provided in multiple stages so that it has parts with different outer diameters depending on the object to be fixed. At the very front of the main shaft 7, a thin-diameter portion 7a for fixing the impeller 120 and a female screw portion 7b are formed from the front side of the thin-diameter portion 7a. The impeller 120 is fixed to the thin-diameter portion 7a of the main shaft 7 by a bolt 19 (not shown) (see FIG. 3 described later). A bearing portion 8 is provided on the rear side of the casing cover 40 to rotatably support the main shaft 7 while it is penetrated. The bearing portion 8 is fixed to the casing cover 40 by a bolt (not shown). The bearing portion 8 is a member for fixing the bearing 9b or multiple bearings (not shown), and is arranged so that the main shaft 7 penetrates the inside of the bearing portion 8, and one or multiple known bearings such as ball bearings are arranged between the main shaft 7 and the bearing portion 8 when viewed in the radial direction. A spacer 10 is provided between the rear side of the bearing 9b and the step portion of the main shaft 7. A shaft seal 9a is provided on the front side of the casing cover 40 and on the rear side of the impeller 20. The shaft seal 9a serves to prevent the fluid pressurized by the impeller 120 from leaking to the outside.

3 is a vertical cross-sectional view of a conventional centrifugal pump 101 passing through the rotation axis Ax. A suction port 5 is formed on the front side of the volute casing 2, and a discharge port 6 is formed on the upper side. Fluid such as water fed from an inflow pipe or the like flows from the suction port 5 forward in the direction of the rotation axis Ax into the suction space 52 inside the volute casing 2 in the direction of the arrow 53, and is sucked into the impeller 120 from the inner opening of the cylindrical part 121 on the front side of the rotating impeller 120. The sucked fluid flows radially outward while being compressed and accelerated by the blades 125, and is discharged from the discharge port 126 into the inside of the volute casing 2. The fluid accelerated at high pressure is guided to the outlet space 63 along the shape of the volute casing 2 in the centrifugal space 62, and is discharged from the discharge port 6 in the direction of the arrow 64. Here, when viewed in a vertical cross section passing through the rotation axis Ax, the centrifugal space 62 and the outlet space 63 appear to be separated, but they are continuous spaces, and in this specification, the space on the inner side of the spiral of the spiral casing 2 is designated as the centrifugal space 62, and the space on the outer side is designated as the output space 63.

The impeller 120 is a rotating body on which multiple blades 125 are formed, and the front edge of the blade 125 is connected to the front wall 127, and the rear edge is connected to the rear wall 128. The blades 125 are manufactured as a single unit, for example, by die casting of metal. Multiple blades 125 are arranged at equal intervals in the circumferential direction. The action of the blades 125 rotating at high speed compresses and accelerates the fluid present between the front wall 127 and the rear wall 128 of the impeller 120, and guides it to the vicinity of the outer periphery of the impeller 120 at high speed, and is discharged from the discharge port 126 into the centrifugal space 62. The casing cover 40 and the shaft seal portion 9a prevent the fluid pressurized by the impeller 120 from leaking to the outside.

The impeller 120 is fixed to the tip (front end) of the main shaft 7 by a bolt 19. The impeller 120 and the main shaft 7 are fixed to prevent freewheeling by forming a key 7c on the main shaft 7 side and a corresponding key groove (not shown in the figure) on the impeller 120 side. The method of fixing the impeller 120 and the main shaft 7 and the fixing structure for preventing freewheeling may be other known structures. The main shaft 7 is rotatably supported by the bearing portion 8 (see FIG. 2) via multiple bearings such as bearing 9b (see FIG. 2). The method of supporting the main shaft 7 in the centrifugal pump 1 is arbitrary, and other known support means may be used.

A cylindrical liner ring 131 is provided in the area surrounded by the dotted line C (in this specification, the area forming the labyrinth gap by the liner ring 131 and the cylindrical part 121 forming the suction port is referred to as the "mouth part") near the boundary area between the cylindrical part 54 forming the suction space 52 of the spiral casing 2 and the front wall surface 55 forming the centrifugal space 62. This mouth part C is the connection point between the rear end of the cylindrical part 54 extending in the cylindrical direction and the inner end of the front wall surface 55 extending radially outward. A mounting part 56 (see FIG. 4 for the reference numerals described later) for mounting the liner ring 131 is formed at this corner. The liner ring 131 is cylindrical and is fixed to the mounting part by press-fitting from the rear side toward the front direction of the rotation axis Ax. The cylindrical part 121, which is the part facing the inner wall surface of the liner ring 131 and forms the suction port of the impeller 120, is formed in an approximately cylindrical shape with an opening at the front end. The outer peripheral wall surface of the cylindrical portion 121 is formed with an inclined surface 22 so that the gap is parallel to the inner peripheral surface of the liner ring 131 in cross section, with a small distance between them. This is to seal the gap so that the liquid present on the high-pressure centrifugal space 62 side does not flow back from the high-pressure centrifugal space 62 side to the low-pressure suction space 52 side.

Figure 4 is an enlarged view of the mouth part C in Figure 3. In the mouth part C of the conventional centrifugal pump 101, a cylindrical part 121 is formed on the inlet side of the impeller 120, and a cylindrical liner ring 131 is arranged to face the outer circumferential surface 121a of the cylindrical part 121. The liner ring 131 is made of metal and is arranged coaxially with the cylindrical part 121 of the impeller 120 at a predetermined distance d. An attachment part 56 is formed at the inner corner of the spiral casing 2 to attach the liner ring 131. The attachment part 56 has a cylindrical surface 56a on the outer circumferential side that serves as the surface for pressing the liner ring 131 into place, and a disk-shaped abutment surface 56b perpendicular to the rotation axis Ax on the front side.

When the centrifugal pump 1 is manufactured, the outer peripheral surface of the cylindrical portion 121 shown by the dotted line and the inner peripheral surface of the liner ring 131 shown by the dotted line are formed so as to have a gap of distance d. This arrangement substantially blocks the flow of fluid between the suction space 52 and the centrifugal space 62 at the opposing portions, preventing the pressurized fluid from flowing back to the suction port 5 side with a lower pressure, and improving the efficiency of the induction of the fluid toward the discharge port 6 by the volute casing 2. With such a structure of the mouth portion C, the surface near the suction port of the impeller 120 wears due to the long-term operation of the centrifugal pump 1, and changes from the initial position shown by the dotted line to the position shown by the solid line. It should be noted that not only the outer surface of the impeller 120 but also other parts (for example, the inside) wear, but the wear of other parts is not properly illustrated in FIG. 4. Similarly, the liner ring 131 side also wears from the initial position shown by the dotted line to the state of the liner ring 131' shown by the solid line. As a result of these wears, the gap between the liner ring 131' and the cylindrical portion 121' becomes large as _d1 . The increase in the gap _d1 leads to a deterioration in the pressure isolation performance of the liquid on the high pressure side and the low pressure side, and therefore the performance degradation of the centrifugal pump 1 is unavoidable.

The centrifugal pump 1 according to the present embodiment is configured so that the gap _d1 shown in FIG. 4 can be returned to the original gap d by disassembly and maintenance. FIG. 5 is a vertical cross-sectional view of the centrifugal pump 1 according to the embodiment of the present invention, passing through the rotation axis Ax. The difference from the conventional centrifugal pump 101 shown in FIG. 3 is the shape of the mouth part C of the volute casing 2, the shape of the cylindrical part 21 of the impeller 20, the shape of the liner ring 31 used, and the use of a spacer 32. The structure other than the mouth part C is the same as that of the conventional centrifugal pump 101, and the same parts are given the same reference numerals. In addition, the volute casing 2 may have a slightly different inner structure (the shape of the mounting part 56 described in detail in FIG. 6(A)) from the conventional volute casing 2, but they are substantially the same, so there is no difference in appearance between the centrifugal pumps 1 and 101.

At the front end of the impeller 20 in the direction of the rotation axis Ax, a cylindrical section 21 is formed which serves as a liquid suction port, and the outer circumferential surface of the cylindrical section 21 is a conical inclined surface 22 whose outer diameter increases linearly from the front side to the rear side. The inner circumferential side of the cylindrical section 21 (the side closest to the rotation axis Ax) is almost cylindrical, but is formed with a certain degree of curvature to suit the flow of liquid inside.

The liner ring section 30 is formed by combining a liner ring 31 and a spacer 32 provided in front of it. The liner ring 31 is approximately cylindrical, but is not completely cylindrical; the first inclined surface 31b is a conical inclined surface that is inclined in the opposite direction to the second inclined surface 22. The spacer 32 is provided between the front wall of the liner ring 31 and the wall surface of the spiral casing 2, and functions as an adjustment member for adjusting the position of the liner ring 31 in the direction of the rotation axis Ax.

Figure 6 shows a liner ring part 30 according to an embodiment of the present invention, (A) is an enlarged view of the mouth part C in Figure 5, and (B) is a perspective view of the liner ring part 30. The liner ring part 30 of this embodiment is provided in place of the conventional liner ring 131 (see Figures 3 and 4), and is composed of a set of a spacer 32 and a liner ring 31. Figure 6 (B) shows a set of the liner ring part 30 (at the time of shipment from the factory). As shown in the figure, the spacer 32 is an integral part formed with the same cross section continuously in the circumferential direction, and has a constant thickness formed from a circular plate material. The liner ring 31 is also a cylindrical integral part made of metal, formed with the same cross section continuously in the circumferential direction. The inner circumferential surface of the liner ring 31 has a slightly cylindrical surface 31a at the front part, but the rear side is formed with an inclined surface 31b.

As can be seen in FIG. 6A, the liner ring 31 is mounted on the mounting portion 56, with a spacer 32 sandwiched between the abutment surface 56b and the front end surface of the liner ring 31. The spacer 32 allows the front-rear position of the liner ring 31 to be adjusted. An inclined surface 22 corresponding to the inclined surface 31b of the liner ring 31 is formed on the outer periphery of the cylindrical portion 21. It is preferable that the inclined surfaces 31b and 22 of the opposing portions of the liner ring 31 and the impeller 20 are parallel to each other with a constant distance d between them. However, it is not necessary that the two inclined surfaces 22 and the inclined surface 31b are completely parallel to each other, and it is sufficient that the minimum gap (the portion of the distance d) can be formed at any point between the inclined surface 31b of the liner ring 31 and the inclined surface 22 of the impeller 20.

The inclined surface 31b and the inclined surface 22 of the ribbon part C are parallel non-contacting surfaces, and are formed so as to be inclined at the same angle θ in the direction intersecting with the direction of the rotation axis Ax. The size of the inclined surface θ may be an angle greater than 0° and less than 90° with respect to the direction of the rotation axis Ax, but it is preferable to form it at an angle greater than 0° and less than 45°, and particularly preferably at an angle of about 10 to 30°. Note that when the centrifugal pump 1 is shipped from the factory, only the liner ring 31 is provided without the spacer 32, and a spacer 32 of an appropriate thickness (length in the direction of the rotation axis Ax) is attached during disassembly and maintenance after use. Also, the front end of the inner surface of the liner ring 31 may not be provided with a cylindrical surface 31a, and the entire surface from the front end to the rear end may be formed with the inclined surface 31b.

Figure 7 is a diagram explaining a method for adjusting the gap in the mouth part C shown by the dotted line in Figure 5 during disassembly and maintenance of the centrifugal pump 1. The impeller 20, main shaft 7, and casing cover 40 shown in Figure 5 can be removed rearward from the volute casing 2 by removing a number of screws arranged on the outer periphery of the casing cover 40, and the liner ring part 30 can be removed. After this removal, it is possible to visually check the wear condition of the liner ring 31 and measure the degree of wear using a measuring instrument.

7A is a partial cross-sectional view showing the state when the liner ring 31 and the spacer 32 are removed from the volute casing 2. The liner ring 31 and the spacer 32 are fixed to the mounting portion 56 of the volute casing 2 by press-fitting. When the first inclined surface 31b of the liner ring 31 wears out due to long-term use, the inclined surface 31b retreats from the opposing second inclined surface 22, and the distance d becomes wide, such as _d1 ( _d1 >d). To deal with this, the liner ring 31 is replaced with a new part. The liner ring 31 and the spacer 32 are removed by moving them rearward as shown by the arrow 35a using a dedicated tool (not shown).

Next, the length L1 (= length of spacer 33 + length of liner ring 31) of the newly installed liner ring part 30 is calculated by measuring the amount of wear on the cylindrical part 21 of the impeller 20. To obtain this calculated value, specific points such as the end point on the suction port 5 side and the end point on the discharge port 6 side are determined in advance on the inclined surface 22 of the impeller 20, the diameter of these parts is measured, and the measured value is compared with the measurement results from the initial manufacturing period and design values to calculate the degree of wear on the impeller 20.

Figure 8 shows how to measure the degree of wear of the impeller 20. The left side shows a side view of the caliper 300, and the right side shows a cross-sectional view of the removed impeller 20 passing through the rotation axis Ax. Using the caliper 300, the inner measuring blades 302, 303 measure the diameter D of the innermost part of the inclined surface 22. The position to be measured is preferably the diameter of the end of the innermost side of the inclined surface 22, but it is also possible to measure another position in the axial direction of the inclined surface 22 using a reference point for measurement.

Returning to FIG. 7 again, the liner ring 31 is not reused once removed in the assembly process, so it is not necessary to measure the wear on the removed liner ring 31 side. Since the gap d is enlarged from the initial manufacturing stage by the amount of wear between the impeller 20 and the liner ring, a new spacer 33 is provided with an increased thickness (= length in the direction of the rotation axis Ax) equivalent to the amount of wear. The liner ring 31 provided adjacent to the spacer 33 is a new, unworn part. The new fixing position of the inclined surface 31b of the liner ring 31 is determined by the thickness of the spacer 33 located between the liner ring 31 and the abutment surface 56b of the volute casing 2. Therefore, if multiple types of spacers 32, 33, etc. with different thicknesses are prepared as adjustment spacers, it becomes possible to appropriately adjust the relative position of the liner ring 31 to the impeller 20 during disassembly maintenance.

The method of attaching the liner ring part 30 is to move the spacer 33 and the liner ring 31 in the forward direction (the direction of the arrow 35b) opposite to the removal direction 35a shown in FIG. 7(A) and press-fit the spacer 33 and the liner ring 31 forward of the rotation axis Ax toward the volute casing 2 relative to the attachment part 56. FIG. 9(A) shows the state after they are pressed-fit. In FIG. 9(A), since the thickness (distance in the direction of the rotation axis Ax) of the newly attached spacer 33 is larger than the removed spacer 32, the position of the inclined surface 31b of the new liner ring 31 can be fixed to a position closer to the impeller 20 in the direction of the rotation axis Ax, that is, a position shifted further rearward than the position of the inclined surface 31b at the time of shipment from the factory. Therefore, even if the inclined surface 22 of the impeller 20 is worn and the inclined surface 22 is retreated rearward in the direction of the rotation axis Ax, it is possible to appropriately adjust the gap d.

Conventionally, the impeller 20 and the liner ring 31 have generally been made of the same material, but in this embodiment, it is desirable to manufacture the liner ring 31 from a metal that is slightly softer and easier to cut than the impeller 20, for example, a material with low hardness. For example, if the material of the impeller 20 is FC200 or SCS13, the material of the liner ring 31 is preferably CAC406, CAC902, or the like. The shape of the spacers 32 and 33 is a ring shape with an outer diameter and an inner diameter that are the same as the outer diameter and the minimum inner diameter of the liner ring 31. In addition, it is desirable to use a metal material that is equal to or stronger than the liner ring 31. This reduces the displacement of the liner ring 31 in the direction of the rotation axis Ax due to deformation or wear of the spacer 32.

As described above, according to the first embodiment, as a result of the adjustment shown in FIG. 7(B), the inclined surface 31b of the liner ring 31 approaches the inclined surface 22 of the opposing part of the impeller 20, and it is possible to adjust the gap d to an appropriate value. This makes it possible to recover the performance degradation of the centrifugal pump 1 caused by long-term use, and therefore it is possible to continue using the centrifugal pump 1 that has been used for a long time without replacing the entire set. The cost required for continued use of the centrifugal pump 1 is the cost of the parts of the liner ring 31 and the spacer 33, and the cost associated with the disassembly, replacement, and adjustment work, which can be kept sufficiently low compared to replacing it with a new one, and therefore an environmentally friendly and eco-friendly centrifugal pump 1 has been realized.

Figure 9 (B) is an enlarged view of the mouth part C of the centrifugal pump 1 showing the second embodiment. In Figure 9 (A), a plurality of spacers 32, 33, etc. with different thicknesses in the direction of the rotation axis Ax are prepared, and a spacer of an appropriate thickness is selected and attached. However, in the second embodiment, a plurality of spacers 34 with the same thickness are prepared, and the number of spacers to be interposed is increased or decreased according to the position of the liner ring 31 to be fixed. The spacer 32 is in a ring shape with an outer diameter and an inner diameter that are the same as the outer diameter and the minimum inner diameter of the liner ring 31. It is sufficient to have one type of spacer with a thickness as thin as possible, such as in 0.1 mm units, but it is also preferable to have multiple types of spacers with a certain thickness, such as in 1 mm units. This allows the adjustment of the gap d, which will be described later, to be performed more efficiently. The material of the spacer 32 is a metal with a strength equal to or greater than that of the liner ring 31. For example, if the material of the liner ring 31 is CAC406 or CAC902, it is preferable to use FC200 or SUS304 as the material of the spacer 32. This reduces the displacement of the liner ring 31 in the direction of the rotation axis Ax due to deformation or wear of the spacer 32. In the state shown in FIG. 9(B), five thin spacers 34 are interposed between the abutment surface 56b. According to the second embodiment, simply by preparing a large number of spacers 34 of the same shape, it is possible to flexibly respond to fixing the liner ring 31 in different positions.

10 is an enlarged view of the mouth part C of the fluid device 1A according to the third embodiment of the present invention. As shown in FIG. 10(A), the centrifugal pump according to the third embodiment is different from the centrifugal pump 1 according to the first embodiment in that the centrifugal pump 1 according to the third embodiment is provided with an impeller 20A having a step in the direction of the rotation axis Ax on the second inclined surface 22 of the opposing portion instead of the impeller 20. The second inclined surface 22 (22a, 22b) of the impeller 20A is formed in a step shape so that the distance between the liner ring 31 and the second inclined surface 31b is wider toward the discharge port 6 side. In this way, the inclined surface 22 has a first inclined surface 22a and a second inclined surface 22b with the end point on the side closer to the suction port 5 as the reference point. The distance between the first inclined surface 22a on the side closer to the suction port 5 and the liner ring 31 is d, and the distance between the end point on the side closer to the discharge port 6 of the inclined surface 22 and the liner ring 31 is d ₃ , where the relationship d<d ₃ is used. However, it is also possible to reverse the relationship of these steps, with the distance between the second step surface 22 and the liner ring 31 being d, and the distance between the first step inclined surface 22a closer to the suction port 5 and the liner ring 31 being _d3 .

Only the surface from the reference point to the first step of the inclined surface 22 of the opposing part of the impeller 20A (here, the first inclined surface 22a) forms a narrow gap d with the inclined surface 31b of the opposing liner ring 31, so that the inclined surface 22a is less susceptible to wear caused by impurities entering the gap _d3 on the second inclined surface 22b side, or wear caused by contact between the liner ring 31 and the inclined surface 22 of the impeller 20A due to vibration. The size and number of steps of the step of the inclined surface 22 of the impeller 20A are not specified, but the smaller the size of the step and the more the number of steps, the better from a functional standpoint. In addition, a step similar to the step of the inclined surface 22 of the impeller 20A may be formed on the inclined surface 31b side of the liner ring 31. In this case, the size of the step per step of the inclined surface of the liner ring 31 is smaller than the size of the step per step of the inclined surface of the impeller 20A. By providing a step on the liner ring 31 side as well, the step on the inclined surface 31b of the liner ring 31 that does not form gap d is positioned close to the opposing inclined surface 22b of the impeller 20A. Therefore, when adjusting the position of the liner ring 31 using the adjustment method described below, the thickness of the spacer 32 required can be reduced, and individual differences in the thickness of each spacer 32 and misalignment of the liner ring 31 due to deformation are less likely to occur.

In Figure 10(B), multiple spacers 34 of the same thickness are used instead of the spacer 33 used in Figure 10(A). The idea is the same as in Example 2 shown in Figure 9(B) in that the number of spacers interposed can be increased or decreased according to the front-to-rear position (position in the direction of the rotation axis Ax) of the liner ring 31 to be fixed. Here, five thin spacers 34 are interposed between the abutment surface 56b. By using this modified example, it is possible to fix the liner ring 31 in different positions simply by preparing a large number of spacers 34 of the same shape.

<Adjustment method>
The adjustment of the gap d between the impeller 20A and the liner ring 31 of the centrifugal pump is basically performed in the same procedure as in the first embodiment, but the method of determining the amount of wear of the cylindrical portion 21A of the impeller 20A is different. In the third embodiment, the amount of wear of the impeller 20A is determined by comparing the number of steps on the inclined surface 22 of the impeller 20A at the initial manufacturing stage with the number of steps at the time of disassembly and maintenance, and by the size of each step and the number of steps that have disappeared due to wear. Thereafter, the thickness of the spacer 32 is increased according to the amount of wear of the inclined surface 22 of the impeller 20A and the angle (θ) of the opposing inclined surface 31b of the liner ring 31 with respect to the direction of the rotation axis Ax, and the position of the liner ring 31 is fixed at a position further rearward in the direction of the rotation axis Ax (a position closer to the impeller 20A) than before the disassembly and maintenance, and the inclined surface 31b of the liner ring 31 is brought closer to the second-stage inclined surface 22b of the impeller 20A, thereby adjusting the gap _d3 to be smaller and adjusting the gap d to an appropriate distance.

In Example 3, an arbitrary number of steps disappear from the reference point side due to wear of the impeller 20A caused by impurities, etc., so that the inclined surface (22b) of the opposing part of the impeller 20A, which is located an arbitrary number of steps away from the reference point and is less affected by wear, is located away from the inclined surface 31b of the liner ring 31 before the gap d is adjusted and does not form a gap d with the inclined surface 31b of the liner ring 31. After the gap is adjusted, the inclined surface 31b of the new liner ring 31 forms a gap d with the inclined surface 31b. This makes it possible to form a gap d with greater precision than in Example 1.

Figure 11 is an enlarged view of the mouth part C of the fluid device according to the fourth embodiment of the present invention. The centrifugal pump 1B according to the fourth embodiment is different from the centrifugal pump 1 according to the first embodiment in that a recess 28 is formed on the inclined surface 22 of the impeller 20B. The recess 28 is a small-diameter hole (e.g., a few millimeters equivalent to the minimum size of a drill) drilled in the opposite direction to the normal direction to the inclined surface 22 of the impeller 20B, and its depth is arbitrary. It is important that the recess 28 does not penetrate to the inner periphery side of the cylindrical part 21B. If the recess 28 is a small hole, for example, with a diameter of about 1 mm, the effect of wear on the inclined surface 22 of the cylindrical part 21 due to the provision of the recess 28 can be ignored. During maintenance of the centrifugal pump 1B, it is possible to calculate the amount of wear of the worn inclined surface 22 by measuring the depth from the bottom surface to the opening surface of the recess 28, which is less susceptible to wear. For example, if the depth of the recess 28 is 10 mm when shipped from the factory, and the depth of the recess 28 is measured to be 6 mm during disassembly and maintenance after many years of use, the amount of wear on the inclined surface 22 can be easily calculated as 10-6=4 mm.

<Adjustment Method>
The adjustment of the gap between the impeller 20B and the liner ring 31 of the centrifugal pump 1B is basically performed in the same procedure as in the first embodiment, but the method of judging the degree of wear of the impeller 20B is different. In this embodiment, the depth of the recess 28 formed on the inclined surface 22 of the portion facing the impeller 20B is measured and compared with the initial depth or the design value to judge the degree of wear of the impeller 20B, and a spacer 32 corresponding to the amount of wear is installed between the abutting surface 56b and the liner ring 31, thereby adjusting the gap between the inclined surface 31b of the liner ring 31 and the cylindrical portion 21B.

The position of the liner ring 31 in the fore-aft direction can be adjusted using a spacer 32 as shown in FIG. 11(A), but it is also possible to use the required number of thin spacers 34 of the same thickness as shown in FIG. 11(B).

Figure 12 is an enlarged view of the mouth part C of the centrifugal pump 1C according to the fifth embodiment of the present invention. As shown in Figure 12, even if the impeller 20C does not have the inclined surface 22 as shown in Figure 6 (A) on the outer circumferential surface of the part (cylindrical part 21C) facing the liner ring 31, and has only a surface 27 parallel to the rotation axis Ax direction, the gap d can be appropriately adjusted by moving the inclined surface 31b of the liner ring 31 so as to approach the surface 27 side of the impeller 20 in the rotation axis Ax direction. In this case, the position of the impeller 20 is configured in advance so that the inclined surface 31b of the liner ring 31 and the tip corner 27a of the cylindrical part 21C of the impeller 20C can come into contact when the rotation axis Ax direction of the liner ring 31 is shifted. That is, the position (radius r) of the tip corner 27a from the axis of rotation Ax is greater than the radius of the tip corner 27a of the inclined surface 22 of the liner ring 31 and smaller than the radius of the rear end corner of the inclined surface 22 of the liner ring 31. By configuring it in this way, it is possible to effectively adjust the gap d between the tip corner 27a of the cylindrical portion 21C facing the liner ring 31.

As described above using Examples 1 to 5 of the present invention, by partially modifying the shape of the cylindrical portion 21 of the impeller 20 to form an inclined surface 22 on the outer periphery, modifying the shape of the liner ring 31 to form an inclined surface 31b, and using spacers 32 to 34, it is possible to appropriately adjust the gap between the inclined surface 31b of the liner ring 31 and the inclined surface 22 of the impeller 20 during disassembly and maintenance. As a result, even if the gap in the mouth portion C expands due to long-term use and the pump performance deteriorates, it is now possible to easily adjust the gap to an appropriate distance during disassembly and maintenance. Note that the present invention is not limited to the above-mentioned examples, and various modifications are possible within the scope of the spirit of the present invention.

REFERENCE SIGNS LIST 1, 1A to 1C Centrifugal pump 2 Volute casing 3 Screw boss 4 Leg 5 Suction port 6 Discharge port 7 Main shaft 7a Thin diameter portion 7b Female thread portion 7c Key 8 Bearing portion 9a Shaft seal portion 9b Bearing 10 Spacer 13, 14 Sensor 19 Bolt 20, 20A to 20C Impeller 21 Cylindrical portion 21a Suction port 21b Inner peripheral wall 22 Inclined surface (second inclined surface) 22a First inclined surface 22b Second inclined surface 23 Inlet 24 Mounting hole 25 Blade 26 Discharge port 27a Tip corner portion 28 Depression 30 Liner ring portion 31 Liner ring 31a Cylindrical surface 31b Inclined surface (first inclined surface)
Description of the Related Art 31c outer cylindrical surface 32 to 34 spacer 40 casing cover 41 screw boss 42 through hole 51 flange 52 suction space 54 cylindrical portion 55 front wall surface 56 mounting portion 56a cylindrical surface 56b abutting surface 61 flange 62 centrifugal space 63 outlet space 101 centrifugal pump 120 impeller 121 cylindrical portion 121a outer circumferential surface 125 blade 127 front wall 128 rear wall 131 liner ring 300 caliper

Claims (11)

an impeller that is fixed to a main shaft that is rotated by a drive source and that applies pressure to the fluid from near the axis toward the outside in a radial direction by rotating;
a casing that houses the impeller, the casing having a fluid suction port and a fluid discharge port, and a flow path that guides the fluid pressurized by the impeller toward the discharge port;
A fluid device including a cylindrical liner ring in a mouth portion of the casing that faces the impeller with a gap therebetween,
a liner ring having a first inclined surface inclined in a direction intersecting with a rotation axis direction of the impeller is provided in a mouth portion of the casing facing the impeller with the minimum gap;
A fluid device characterized in that a spacer for adjusting a size of a gap between the first inclined surface and the impeller is provided between the liner ring and an attachment portion of the liner ring in the casing. A surface of the impeller facing the liner ring is formed by a second inclined surface inclined in a direction intersecting with the rotation axis direction,
2. The fluid device according to claim 1, wherein the first inclined surface and the second inclined surface are formed so as to be parallel to each other at the same angle when viewed in a cross section including the rotation axis. The fluid device according to claim 2, characterized in that the distance between the mounting part and the liner ring in the direction of the rotation axis is adjusted by preparing the annular spacers having different thicknesses and lengths in the direction of the rotation axis, and placing one of them between the mounting part and the liner ring. The fluid device according to claim 2, characterized in that the spacer, which is an annular shape having the same length in the direction of the rotation axis of the impeller, is arranged between the mounting part and the liner ring, so that the distance in the direction of the rotation axis between the mounting part and the liner ring is adjusted. The fluid device according to claim 3 or 4, characterized in that the angle of the first inclined surface with respect to the main axis is greater than 0 degrees and less than 45 degrees. The fluid device according to claim 4, characterized in that a non-through hole recessed in a direction perpendicular to the second inclined surface is formed in a portion of the circumferential direction of the second inclined surface of the impeller. The fluid device according to claim 5, characterized in that the second inclined surface is formed in a stepped shape with multiple inclined surfaces each parallel to the first inclined surface. an impeller that is fixed to a main shaft that is rotated by a drive source and that applies pressure to the fluid from near the axis toward the outside in a radial direction by rotating;
a casing for housing the impeller, the casing having a fluid suction port and a fluid discharge port, and a flow path for guiding the fluid pressurized by the impeller toward the discharge port;
A fluid device including a cylindrical liner ring in a mouth portion of the casing that faces the impeller with a gap therebetween,
a liner ring facing the impeller with the minimum gap is provided with a first inclined surface inclined in a direction intersecting with a rotation axis direction of the impeller;
a second inclined surface is formed on the liner ring so as to face the first inclined surface in parallel therewith;
A gap adjustment method for fluid equipment, characterized in that the amount of wear on the second inclined surface of the impeller is measured when the casing is disassembled, and a spacer of a predetermined thickness is interposed between the liner ring and the mounting portion of the casing so as to fix the mounting position of the liner ring at a position close to the impeller based on the amount of wear. The gap adjustment method for fluid equipment according to claim 8, characterized in that the amount of wear of the impeller during gap adjustment is determined by measuring the diameter of the innermost position of the second inclined surface of the impeller and comparing it with the value at the manufacturing stage or the design value. The second inclined surface is formed of a plurality of inclined surfaces,
A gap adjustment method for fluid equipment as described in claim 9, characterized in that the amount of wear of the impeller during the gap adjustment is determined by comparing the number of steps remaining on the inclined surface of the impeller with the number of steps at the time of initial manufacture, based on the size of each step and the number of steps that have disappeared due to wear. a non-through hole recessed in a direction perpendicular to the second inclined surface is formed in a part of the second inclined surface in a circumferential direction,
The gap adjusting method for fluid equipment according to claim 10, characterized in that the amount of wear of the impeller during the gap adjustment is determined by measuring the depth of the remaining depression and comparing it with the depth at the time of initial manufacture.

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