Fluid apparatus and clearance adjustment method of fluid apparatus

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

[Technical field]

[0001] The present invention relates to a fluid device in which the gap between an impeller and a liner ring is adjustable, and a method for adjusting the gap. [Background technology]

[0002] In modern society, where measures against environmental problems 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, it has been devised to repair and reuse old pumps. To reuse old pumps, it is necessary to restore them to the same standard in both appearance and performance as new ones. However, the impeller, which is particularly important for performance, wears out 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 initial manufacturing stage 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 together with the bearing part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-210869 A Summary of the Invention [Problem to be solved by the invention]

[0004] 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. In this method, the impeller is moved together with the bearing part, so for example, the ball bearing is adjusted by being pressed between the main shaft and the casing cover, which places extra load on the mechanism parts other than the gap part, which may result in a shortened product life. In consideration of the environmental impact, it is preferable to make each part long and reusable.

[0005] 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. [Means for solving the problem]

[0006] 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 with the direction of the rotation axis.

[0007] 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, thereby adjusting 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 a necessary number of spacers are placed between the mounting portion and the liner ring, thereby adjusting 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. Also, 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 wear amount of the surface of the blade portion 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.

[0008] According to 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 as to move closer to the impeller and then be fixed according to the measured amount of wear. This adjustment is performed by interposing a spacer of a predetermined 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. Effect of the Invention

[0009] According to the present invention, the amount of wear between the impeller and the liner ring can be easily measured during disassembly and maintenance of the fluid equipment, and the spacer can be provided to appropriately adjust the gap between the liner ring and the impeller. Furthermore, since the 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 the shaft seal) other than the minimum gap part and other components. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view showing the appearance of a centrifugal pump 1 according to an embodiment of the present invention. [Diagram 2] FIG. 1 is an exploded perspective view of a conventional centrifugal pump 101. [Diagram 3] 1 is a vertical cross-sectional view passing through a rotation axis Ax of a conventional centrifugal pump 101. [Figure 4] 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. [Diagram 5] 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. [Figure 6] 5A is an enlarged view of the mouth portion C in FIG. 5, and FIG. [Figure 7] 5A to 5C are diagrams illustrating a procedure for adjusting the clearance of the centrifugal pump 1 according to the present embodiment. [Figure 8] 1A to 1C are diagrams illustrating an example of a method for measuring the gap of the mouth part C of the centrifugal pump 1 according to the present embodiment. [Figure 9] 1A is an enlarged view of a mouse part C according to a first embodiment, and FIG. 1B is an enlarged view of a mouse part C according to a second embodiment. [Figure 10] 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. [Figure 11] 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. [Figure 12] 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, 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 using 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 illustrated examples, and can be combined as appropriate. In addition, in each figure, common or similar components are given the same reference numerals, and duplicated explanations thereof will be omitted. EXAMPLES

[0012] FIG. 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 and increasing the flow rate of a liquid sucked by an impeller (described later) and discharging it. The volute casing 2 is provided with a suction port 5 that sucks in a 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 of this embodiment is mainly assumed to be clean water, but other liquids may also be used.

[0013] The rear side of the volute casing 2 is closed by a casing cover 40. At the outer edge of the rear opening of the volute casing 2, screw bosses 3 for screw holes are formed in multiple locations. In addition, around the outer periphery of the casing cover 40, multiple screw bosses 41 for through holes for passing through screws or bolts (not shown) are formed. At the rear side of the casing cover 40, a through hole (not visible in FIG. 1) for passing through the main shaft 7 is formed, 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 lower side of the volute 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 through screws or bolts (not shown) are formed.

[0014] The centrifugal space accommodates a main shaft 7 arranged to penetrate the spiral casing 2 and an impeller 20 (see FIG. 5 described later) fixed to the main shaft 7 so as to be integrally rotatable. The main shaft 7 extends rearward from inside the spiral casing 2, penetrating the bearing portion 8. A drive source (not shown) is connected to the main shaft 7 extending rearward beyond the bearing portion 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 an engine, a water wheel, a windmill, etc. can be used as long as they are devices capable of supplying rotational force to the main shaft 7.

[0015] Fig. 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 Fig. 1 are the shape of the liner ring 131, the shape of a 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 Fig. 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 Figs. 2 to 4 have the same shape as seen from the outside.

[0016] A flow path for flowing a fluid is provided inside the spiral casing 2, and a circular opening 2a for inserting the impeller 120 is formed on the rear side. 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 a portion adjacent to and facing 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.

[0017] The main shaft 7 is an integrally molded metal member long in the front-rear direction, and is provided in multiple stages so as to have portions with different outer diameters depending on the object to be fixed. At the frontmost part of the main shaft 7, a thin-diameter part 7a for fixing the impeller 120 is formed, and a female screw part 7b is formed from the front side of the thin-diameter part 7a. The impeller 120 is fixed to the thin-diameter part 7a of the main shaft 7 by a bolt 19 (not shown) (see FIG. 3 described later). A bearing part 8 is provided on the rear side of the casing cover 40 to rotatably support the main shaft 7 in a state in which the main shaft 7 is inserted. The bearing part 8 is fixed to the casing cover 40 by a bolt (not shown). The bearing part 8 is a member for fixing the bearing 9b or a plurality of bearings (not shown), and is arranged so that the main shaft 7 passes through the inside of the bearing part 8, and one or a plurality of known bearings such as a ball bearing are arranged between the main shaft 7 and the bearing part 8 when viewed in the radial direction. A spacer 10 is provided between the rear side of the bearing 9b and the stepped part 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.

[0018] FIG. 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. A fluid such as water fed from an inflow pipe or the like flows from the suction port 5 at the front in the direction of the rotation axis Ax into a suction space 52 inside the volute casing 2 in the direction of the arrow 53, and is sucked into the impeller 120 from an opening on the inside of the cylindrical part 121 at 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 in the centrifugal space 62 along the shape of the volute casing 2, 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 actually continuous spaces, and in this specification, the space on the inner side of the spiral of the spiral casing 2 is given the symbol 62 as the centrifugal space, and the space on the outer side is given the symbol 63 as the output space.

[0019] The impeller 120 is a rotor on which a plurality of blades 125 are formed, and the front edge of the blade 125 is connected to a front wall 127, and the rear edge is connected to a rear wall 128. The blade 125 is integrally manufactured, for example, by die casting of metal. A plurality of blades 125 are arranged at equal intervals in the circumferential direction. The fluid present between the front wall 127 and the rear wall 128 of the impeller 120 is compressed and accelerated by the action of the blades 125 rotating at high speed, and is guided at high speed to the vicinity of the outer periphery of the impeller 120, 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.

[0020] 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 each other so that they do not spin freely, with a key 7c formed on the main shaft 7 side and a corresponding key groove (not shown in the figure) formed on the impeller 120 side. The method of fixing the impeller 120 and the main shaft 7 and the fixing structure for preventing the impeller 120 from spinning freely may be other known structures. The main shaft 7 is rotatably supported by a bearing portion 8 (see FIG. 2) via a plurality of bearings such as a bearing 9b (see FIG. 2). The method of supporting the main shaft 7 in the centrifugal pump 1 is arbitrary, and other known supporting means may be used.

[0021] A cylindrical liner ring 131 is provided in a portion surrounded by a dotted line C (in this specification, the portion forming a labyrinth gap by the liner ring 131 and the cylindrical portion 121 forming the suction port is referred to as a "mouth portion") near the boundary region between the cylindrical portion 54 forming the suction space 52 of the volute casing 2 and the front wall surface 55 forming the centrifugal space 62. This mouth portion C is a connection point between the rear end of the cylindrical portion 54 extending in the cylindrical direction and the inner end of the front wall surface 55 extending radially outward. An attachment portion 56 (reference numerals are shown in FIG. 4 described later) for attaching the liner ring 131 is formed in this corner portion. The liner ring 131 is cylindrical and is fixed to the attachment portion by press-fitting from the rear side toward the front direction in the direction of the rotation axis Ax. The cylindrical portion 121, which is a portion facing the inner wall surface of the liner ring 131 and forms the suction port of the impeller 120, is formed in a substantially cylindrical shape with an opening at the front end. The inclined surface 22 is formed so that the outer peripheral wall surface of the cylindrical portion 121 forms a gap parallel to the inner peripheral surface of the liner ring 131 in a cross-sectional view 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 backward from the high-pressure centrifugal space 62 side to the low-pressure suction space 52 side.

[0022] Fig. 4 is an enlarged view of the mouth part C in Fig. 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. A mounting part 56 is formed at an inner corner of the spiral casing 2 to mount the liner ring 131. The mounting part 56 has a cylindrical surface 56a on the outer circumferential side to serve as a surface for press-fitting the liner ring 131, and a disk-shaped abutment surface 56b perpendicular to the rotation axis Ax on the front side.

[0023] 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 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.

[0024] 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 the 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.

[0025] A cylindrical portion 21 that serves as a liquid suction port is formed at the front end of the impeller 20 in the direction of the rotation axis Ax, and the outer circumferential surface of the cylindrical portion 21 forms 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 portion 21 (the side closer to the rotation axis Ax) is almost cylindrical, but is formed with a certain degree of curvature to suit the flow of liquid flowing inside.

[0026] The liner ring section 30 is formed by combining a liner ring 31 and a spacer 32 provided on the front side thereof. The liner ring 31 is substantially cylindrical, but is not completely cylindrical, and has a conical inclined surface such that a first inclined surface 31b 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 volute 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.

[0027] FIG. 6 shows a liner ring part 30 according to an embodiment of the present invention, where (A) is an enlarged view of the mouth part C in FIG. 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 FIG. 3 and FIG. 4), and is composed of a set of a spacer 32 and a liner ring 31. FIG. 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 certain thickness formed by a circular ring-shaped plate material. The liner ring 31 is also an integral cylindrical metal part formed with the same cross section continuously in the circumferential direction. The inner peripheral surface of the liner ring 31 has a front part that is slightly cylindrical 31a, but the rear side is formed with an inclined surface 31b.

[0028] As can be seen in FIG. 6(A), the liner ring 31 is mounted on the mounting portion 56, and a spacer 32 is sandwiched between the abutting 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. The inclined surfaces 31b and 22 of the opposing portions of the liner ring 31 and the impeller 20 are preferably parallel to each other with a constant distance d between them. However, the two inclined surfaces 22 and the inclined surface 31b do not necessarily need to be completely parallel, 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.

[0029] The inclined surface 31b and the inclined surface 22 of the ribbon portion C are parallel non-contact 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 about 10 to 30°. Note that when the centrifugal pump 1 is shipped from the factory, the spacer 32 is not provided, and only the liner ring 31 is provided, 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 cylindrical surface 31a may not be provided at the front end of the inner peripheral surface of the liner ring 31, and the entire surface from the front end to the rear end may be formed with the inclined surface 31b.

[0030] Fig. 7 is a diagram for explaining a method for adjusting the gap at the mouth part C shown by the dotted line in Fig. 5 during disassembly and maintenance of the centrifugal pump 1. The impeller 20, main shaft 7, and casing cover 40 shown in Fig. 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 becomes possible to visually check the wear state of the liner ring 31 and measure the degree of wear using a measuring instrument.

[0031] FIG. 7(A) 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 part 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 wider, such as d1 (d1>d). To address this issue, 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).

[0032] 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 cylindrical part 21 of 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 for inclined surface 22 of impeller 20, the diameter of those parts is measured, and the measured value is compared with the measurement result at the beginning of manufacture and the design value to calculate the degree of wear on impeller 20.

[0033] 8 is a diagram showing how the degree of wear of the impeller 20 is measured. The left side shows a side view of the caliper 300, and the right side shows a cross-sectional view passing through the rotation axis Ax of the removed impeller 20. Using the caliper 300, the diameter D of the innermost portion of the inclined surface 22 is measured with the inside measuring blades 302 and 303. The position to be measured is preferably the diameter of the end portion on the innermost side of the inclined surface 22, but another position in the axial direction of the inclined surface 22 may be measured using a reference point for measurement.

[0034] 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 of the removed liner ring 31. 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) corresponding to the amount of wear. The liner ring 31 provided adjacent to the spacer 33 is a new part that is not worn. 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 abutting 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.

[0035] 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 to the attachment part 56 toward the volute casing 2 on the forward side of the rotation axis Ax. 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, the gap d can be appropriately adjusted.

[0036] Conventionally, the impeller 20 and the liner ring 31 are generally made of the same material. In this embodiment, however, the liner ring 31 is preferably made of a metal that is slightly softer and easier to cut than the impeller 20, for example, a material with low hardness. For example, when 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 having the same outer diameter and inner diameter as the outer diameter and minimum inner diameter of the liner ring 31. In addition, the material of the spacers 32 and 33 is preferably a metal having the same strength as or greater than that of the liner ring 31. This reduces the displacement of the liner ring 31 in the direction of the rotation axis Ax due to the deformation or wear of the spacer 32.

[0037] As described above, according to the first embodiment, as a result of the adjustment as shown in Fig. 7(B), the inclined surface 31b of the liner ring 31 approaches the inclined surface 22 of the opposing portion of the impeller 20, and the gap d can be adjusted to be appropriate. This makes it possible to recover the performance deterioration of the centrifugal pump 1 caused by long-term use, and therefore makes it 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 replacement with a new one, thereby realizing an environmentally friendly and eco-friendly centrifugal pump 1. EXAMPLES

[0038] FIG. 9(B) is an enlarged view of the mouth part C of the centrifugal pump 1 showing the second embodiment. In FIG. 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 with 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 makes it possible to more efficiently adjust the gap d, which will be described later. 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, when 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 spacer 32 and the abutting surface 56b. According to the second embodiment, it is possible to flexibly respond to the need to fix the liner ring 31 at different positions by simply preparing a large number of spacers 34 of the same shape.

Example

[0039] FIG. 10 is an enlarged view of the housing portion C of the fluid equipment 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 of the first embodiment in that it 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 surfaces 22 (22a, 22b) of the impeller 20A are formed in a stepped shape so as to be away from the inclined surface 31b toward the discharge port 6 side and the interval from the lining 31 is widened. Thus, the inclined surface 22 has a first-stage inclined surface 22a and a second-stage inclined surface 22b with the end point on the side closer to the suction port 5 as a reference point. The interval between the first-stage inclined surface 22a closer to the suction port 5 and the lining 31 is d, and the interval between the end point closer to the discharge port 6 of the inclined surface 22 and the lining 31 is d3. Here, the relationship of d < d3 is set. However, it is also possible to reverse the relationship of these steps, set the interval between the second-stage stepped surface 22 and the lining 31 as d, and set the interval between the first-stage inclined surface 22a closer to the suction port 5 and the lining 31 as d3.

[0040] 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. This makes it possible to reduce the thickness of the spacer 32 required when adjusting the position of the liner ring 31 using the adjustment method described below, and makes it less likely that individual differences in the thickness of each spacer 32 or misalignment of the liner ring 31 due to deformation will occur.

[0041] In Fig. 10(B), a plurality of spacers 34 of the same thickness are used instead of the spacer 33 used in Fig. 10(A). The idea of ​​increasing or decreasing the number of spacers interposed according to the front-rear position (position in the direction of the rotation axis Ax) of the liner ring 31 to be fixed is the same as in the second embodiment shown in Fig. 9(B). Here, five thin spacers 34 are interposed between the abutting surface 56b. By using this modified example, it is possible to fix the liner ring 31 at different positions simply by preparing a large number of spacers 34 of the same shape.

[0042] <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 for 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 adjusted 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.

[0043] 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 before adjustment of the gap d, the inclined surface (22b) of the opposing part of the impeller 20A, which is less affected by wear and is located an arbitrary number of steps away from the reference point and was located away from the inclined surface 31b of the liner ring 31 and did not form a gap d with the inclined surface 31b of the liner ring 31, forms a gap d with the inclined surface 31b of a new liner ring 31 after the gap adjustment, so that a more accurate gap d can be formed compared to Example 1. EXAMPLES

[0044] FIG. 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 portion 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 portion 21 due to the provision of the recess 28 can be ignored. During maintenance of the centrifugal pump 1B, the depth from the bottom surface to the opening surface of the recess 28, which is less susceptible to wear, can be measured to calculate the amount of wear on the worn inclined surface 22. For example, if the depth of recess 28 is 10 mm when shipped from the factory, and the depth of recess 28 is measured to be 6 mm during disassembly and maintenance after many years of use, the amount of wear of inclined surface 22 can be easily calculated as 10-6=4 mm.

[0045] <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.

[0046] The fore-aft position of the liner ring 31 can be adjusted using a spacer 32 as shown in Figure 11(A), but it is also possible to interpose the required number of thin spacers 34 of the same thickness as shown in Figure 11(B). EXAMPLES

[0047] 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 FIG. 12, even if the impeller 20C does not have the inclined surface 22 as shown in FIG. 6(A) on the outer circumferential surface of the part (cylindrical part 21C) facing the liner ring 31 and has only the 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 to a positional relationship in which the inclined surface 31b of the liner ring 31 and the tip corner part 27a of the cylindrical part 21C of the impeller 20C can come into contact with each other when the liner ring 31 is shifted in the rotation axis Ax direction. That is, the positional relationship is such that the position (radius r) of the tip corner 27a from the rotation axis Ax is larger 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 in this way, it is possible to effectively adjust the gap d between the liner ring 31 and the tip corner 27a of the cylindrical portion 21C facing it.

[0048] As described above using Examples 1 to 5 of the present invention, the shape of the cylindrical portion 21 of the impeller 20 is partially changed to form the inclined surface 22 on the outer periphery, the shape of the liner ring 31 is changed to form the inclined surface 31b, and spacers 32 to 34 are used, so that 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 is reduced, the gap can be easily adjusted to an appropriate interval 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 gist of the present invention. [Explanation of symbols]

[0049] 1, 1A~1C Centrifugal pump 2 Volute casing 3 Screw boss 4 Leg 5 Inlet 6 Outlet 7 Main shaft 7a Thin-diameter portion 7b Female thread portion 7c Key 8 Bearing portion 9a shaft seal 9b bearing 10 spacer 13, 14 sensor 19 Volts 20, 20A~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 28 recess 30 liner ring part 31 liner ring 31a cylindrical surface 31b inclined surface (first inclined surface) 31c Outer cylindrical surface 32~34 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 periphery 125 blade 127 front wall 128 Rear wall 131 Liner ring 300 Caliper

Claims

1. 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 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 the 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.

2. 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.

3. The fluid device described in claim 2, characterized in that the distance in the direction of the rotation axis between the mounting portion and the liner ring is adjusted by preparing annular spacers having different thicknesses and lengths in the direction of the rotation axis and placing one of them between the mounting portion and the liner ring.

4. The fluid device described in claim 2, characterized in that the distance between the mounting portion and the liner ring in the direction of the rotational axis is adjusted by placing multiple annular spacers between the mounting portion and the liner ring, the spacers having the same length in the direction of the rotational axis of the impeller.

5. 5. The fluid device according to claim 3, wherein the angle that the first inclined surface forms with respect to the principal axis is greater than 0 degrees and less than 45 degrees.

6. The fluid device according to claim 4, wherein a non-through hole is formed in a part of the circumferential direction of the second inclined surface of the impeller, the non-through hole being recessed in a direction perpendicular to the second inclined surface.

7. 6. The fluid device according to claim 5, wherein the second inclined surface is formed in a stepped shape with a plurality of inclined surfaces each parallel to the first inclined surface.

8. 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.

9. A gap adjustment method for fluid equipment as described in 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 a value at the manufacturing stage or a design value.

10. 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.

11. 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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