Fluid equipment and method for adjusting the gap of fluid equipment

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 allowing adjustment of a gap between an impeller and a liner ring, and a method of adjusting the gap. [Background Art]

[0002] In modern society where countermeasures against environmental issues such as global warming are an urgent task, manufacturing that considers environmental aspects in addition to simple product quality is required. In the pump business, it has been common to discard old pumps and replace them with new ones. However, in consideration of environmental impact, repairing and reusing old pumps has been conceived. To reuse an old pump, both its appearance and performance need to be restored to the same level as a new product. In particular, the impeller, which is the core of performance, will cause wear on the opposing portions of the liner ring and the impeller after years of use, resulting in an enlarged gap, which often makes it impossible to maintain the initial performance achieved when the product was manufactured. Regarding the gap between the liner ring and the impeller, Patent Document 1 discloses a technique of adjusting the gap by moving the impeller together with the bearing portion. [Prior Art Document] [Patent Document]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2019-210869 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In the technique of Patent Document 1, the gap is adjusted by moving the impeller of the fluid device in the rotation axis direction toward the liner ring to narrow the gap. In this method, since the impeller is moved together with the bearing portion, for example, a ball bearing is adjusted by being compressed while being sandwiched between the main shaft and the casing cover, which applies an excessive load to the mechanism portions other than the gap portion but and may consequently shorten the service life of the product. In view of environmental impact, it is preferable that a single component can be used repeatedly for a long service life.

[0005] The present invention has been made in view of the above background, and its purpose is to provide a fluid device that can adjust the gap between a liner ring and an impeller without placing an extra load on mechanical components other than the component that forms the gap, and a method for adjusting the gap. Another object of the present invention is to provide a fluid device and a method for adjusting the gap therefor, which allows for easy adjustment of the gap even when 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] The following are some of the representative features of the invention disclosed in this application. According to one feature of the present invention, a fluid device comprising a main shaft rotated by a drive source, an impeller fixed to the main shaft and rotating to apply pressure to a fluid radially outward from near the axis, a casing housing the impeller and having a fluid intake port and discharge port, and a flow path for guiding the fluid pressurized by the impeller toward the discharge port, and a cylindrical liner ring in the mouth portion of the casing facing the impeller with a gap between them, wherein the liner ring has a first inclined surface formed on the casing side of the mouth portion facing the impeller with the smallest possible gap, inclined in a direction intersecting the rotation axis direction of the impeller. The liner ring is inserted into the casing toward the rotation axis direction toward the inner wall side of the casing and is positioned to face the impeller with a gap between them. Furthermore, a spacer is interposed between the mounting portion 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 was formed parallel to the first inclined surface in the portion of the impeller facing the liner ring. The first and second inclined surfaces are inclined in a direction that intersects with the rotation axis.

[0007] According to another feature of the present invention, the distance between the mounting portion and the liner ring in the direction of rotational axis is adjusted by preparing multiple annular spacers of different lengths in the direction of rotational axis and placing one of them between the mounting portion and the liner ring. Alternatively, the distance between the first inclined surface and the second inclined surface is adjusted by preparing multiple annular spacers of the same size and placing the required number of spacers between the mounting portion and the liner ring. Preferably, the angle that the first inclined surface makes with respect to the rotational axis is greater than 0 degrees and less than 45 degrees. Furthermore, by forming a non-through hole in a part of the circumferential direction of the second inclined surface of the impeller, which is recessed in a direction perpendicular to the second inclined surface, the amount of wear on the surface of the blades can be measured by measuring the depth of the non-through hole after many years of use of the fluid equipment. In addition, the second inclined surface of the impeller may be formed in a stepped manner with multiple inclined surfaces 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 them and the first inclined surface is different.

[0008] According to yet another feature of the present invention, when the casing is disassembled during disassembly and maintenance of 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 to a position closer to the impeller and then 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 portion 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. Furthermore, if the second inclined surface is formed with multiple inclined surfaces, the amount of wear on the impeller during 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 time of manufacturing, and determining the size of each step and the number of steps that have disappeared due to wear. [Effects of the Invention]

[0009] 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 gap between the liner ring and the impeller can be appropriately adjusted by providing a spacer. Furthermore, since this adjustment does not involve movement of the impeller in the direction of its rotation axis Ax, the gap between the liner ring and the impeller can be appropriately adjusted without putting stress on other parts (especially bearings and shaft seals) or other components other than the smallest gap area. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing the external appearance of a centrifugal pump 1 according to an embodiment of the present invention. [Figure 2] This is an exploded perspective view of a conventional centrifugal pump 101. [Figure 3] This is a vertical cross-sectional view of a conventional centrifugal pump 101 passing through its rotation axis Ax. [Figure 4] This is a partial cross-sectional view showing the condition of the impeller 120' and liner ring 131' after long-term use of a conventional centrifugal pump 101. [Figure 5] This is a vertical cross-sectional view of a centrifugal pump 1 according to an embodiment of the present invention, passing through the rotation axis Ax. [Figure 6] (A) is an enlarged view of the mouse part C in Figure 5, and (B) is a perspective view of the liner ring part 30. [Figure 7] This figure shows the procedure for adjusting the gap of the centrifugal pump 1 according to this embodiment. [Figure 8] This figure shows an example of a method for measuring the gap in the mouse portion C of the centrifugal pump 1 according to this embodiment. [Figure 9] (A) is an enlarged view of the mouse part C of the first embodiment, and (B) is an enlarged view of the mouse part C according to the second embodiment. [Figure 10] This is an enlarged view of the mouse portion C of the centrifugal pump 1A according to a third embodiment of the present invention. [Figure 11] This is an enlarged view of the mouse portion C of the centrifugal pump 1B according to the fourth embodiment of the present invention. [Figure 12] This is an enlarged view of the mouse portion C of the centrifugal pump 1C according to the fifth embodiment of the present invention. [Modes for carrying out the invention]

[0011] The embodiments of the present invention will be described below with reference to the drawings. In this embodiment, as an example of fluid equipment, a centrifugal pump called a single-suction single-stage volute pump will be used for explanation. However, the present invention is not limited to centrifugal pumps but can be applied to fluid equipment in general that uses an impeller. The following figures are schematic in order to allow for a sufficient understanding of the present invention. Therefore, the present invention is not limited to the illustrated examples and can be combined as appropriate. In addition, common or similar components in each figure are denoted by the same reference numerals, and their redundant explanations are omitted. [Examples]

[0012] Figure 1 is a perspective view of a fluid device (centrifugal pump 1) according to one embodiment of the present invention. In this embodiment, the explanation will assume that the fluid device is 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 velocity of the liquid drawn in by the impeller, which will be described later, and then discharging it. The volute casing 2 is provided with a suction port 5 for drawing in fluid from the front to the rear in the direction of the rotation axis Ax, and a discharge port 6 for discharging fluid in a direction perpendicular to the rotation axis Ax, in this case 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.

[0013] A rear side of the spiral casing 2 is closed by a casing cover 40. Screw bosses 3 for screw holes at a plurality of positions are formed on an outer edge of a rear opening of the spiral casing 2. In addition, a plurality of screw bosses 41 for through holes for passing unshown screws or bolts are formed around an outer circumferential side of the casing cover 40. A through hole (not visible in Figure 1) for passing the main shaft 7 is formed on a rear side of the casing cover 40, and a bearing portion 8 that rotatably supports the main shaft 7 is provided coaxially with the through hole. A leg portion 4 is connected to a lower side of the spiral casing 2. The leg portion 4 is a fixing fixture for bolting the centrifugal pump 1 to a floor, a pedestal or the like, and is formed with a plurality of through holes 4a for passing unshown screws or bolts therethrough.

[0014] Inside the centrifugal space, a main shaft 7 arranged to pass through the spiral casing 2, and an impeller 20 (refer to Figure 5 described later) fixed to the main shaft 7 so as to be integrally rotatable are housed. The main shaft 7 extends from the inside of the spiral casing 2, passes through the bearing portion 8, and extends to the rear side. A drive source (not shown) is connected to the main shaft 7 extending further to the rear side than the bearing portion 8, and rotates the impeller 20 (refer to Figure 5 described later). The drive source is, for example, a motor, but the drive source of the fluid device of the present embodiment is not limited to a motor. Various known power sources such as engines, water turbines, and windmills can be used as long as the device can supply rotational force to the main shaft 7.

[0015] Figure 2 is an exploded perspective view of a conventional centrifugal pump 101. The differences between the conventional centrifugal pump 101 and the centrifugal pump 1 of the present embodiment shown in Figure 1 are only the shape of the liner ring 131, the partial shape of the impeller 120, and the shape near the mounting portion of the liner ring 131 in the spiral casing 2. Other than that, the centrifugal pump 1 of the present embodiment shown in Figure 1 can be manufactured using the same components as the conventional centrifugal pump 101. Therefore, the externally visible shape of the centrifugal pump 1 of the present embodiment and the conventional centrifugal pump 101 shown in Figures 2 to 4 is the same.

[0016] The inside of the spiral casing 2 is provided with a fluid passage, and a circular opening 2a is formed on the rear side for inserting the impeller 120. The opening 2a is closed by the casing cover 40. A cylindrical liner ring 131 is provided on the inner wall portion of the spiral casing 2, 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 a long, one-piece molded metal member, and is provided in multiple stages with different outer diameters depending on the object to be fixed. At the foremost end of the main shaft 7 is a narrow-diameter section 7a for fixing the impeller 120, and a female threaded section 7b is formed from the front side of the narrow-diameter section 7a. The impeller 120 is fixed to the narrow-diameter section 7a of the main shaft 7 by bolts 19 (not shown, see Figure 3 below). A bearing section 8 is provided on the rear side of the casing cover 40 to allow rotational support of the main shaft 7 with it passing through. The bearing section 8 is fixed to the casing cover 40 by bolts (not shown). The bearing section 8 is a member for fixing a bearing 9b or multiple bearings (not shown), and is arranged so that the main shaft 7 passes through the inside of the bearing section 8, with one or more known bearings such as ball bearings arranged between the main shaft 7 and the bearing section 8 in the radial direction. A spacer 10 is provided between the rear side of the bearing 9b and the stepped section of the main shaft 7. A shaft seal portion 9a is provided on the front side of the casing cover 40 and on the rear side of the impeller 120. The shaft seal portion 9a serves to prevent the fluid pressurized by the impeller 120 from leaking to the outside. Tsu.

[0018] Figure 3 is a vertical cross-sectional view of a conventional centrifugal pump 101 passing through the rotation axis Ax. An inlet 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 supplied from an inlet pipe, etc., flows from the inlet 5 at the front in the direction of the rotation axis Ax into the suction space 52 inside the volute casing 2 in the direction of arrow 53, and is sucked into the impeller 120 through an opening on the inside of the cylindrical part 121 at the front of the rotating impeller 120. The sucked-in fluid is compressed and accelerated by the blades 125 and flows radially outward, and is discharged into the volute casing 2 from the discharge port 126. The fluid accelerated at high pressure is guided in the centrifugal space 62 along the shape of the volute casing 2 to the outlet space 63, and is discharged from the discharge port 6 in the direction of 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 these are continuous spaces. In this specification, the space on the inner circumference side of the spiral casing 2 is denoted as the centrifugal space 62, and the space on the outer circumference side is denoted as the output space 63.

[0019] The impeller 120 is a rotating body formed of multiple blades 125, the front edges of which are connected to the front wall 127 and the rear edges of which are connected to the rear wall 128. The blades 125 are manufactured integrally, for example, by die-casting of metal. Multiple 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 rapidly rotating blades 125, and is guided at high speed to the vicinity of the outer circumference of the impeller 120, where it is discharged into the centrifugal space 62 through the outlet 126. The casing cover 40 and the shaft seal 9a prevent leakage of the fluid pressurized by the impeller 120 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 together by a key 7c formed on the main shaft 7 side and a corresponding keyway (not visible in the figure) formed on the impeller 120 side to prevent free rotation. Note that other known structures may be used for the fixing method of the impeller 120 and the main shaft 7, and for the fixing structure to prevent free rotation. The main shaft 7 is rotatably supported by a bearing section 8 (see Figure 2) via a plurality of bearings such as bearing 9b (see Figure 2). Note that the method of supporting the main shaft 7 in the centrifugal pump 1 is arbitrary and may be implemented by other known support means.

[0021] A cylindrical liner ring 131 is provided in the area near the boundary region between the cylindrical portion 54 that forms the suction space 52 of the vortex casing 2 and the front wall surface 55 that forms the centrifugal space 62, in the portion enclosed by the dotted line C (in this specification, the portion that forms a labyrinth gap by the liner ring 131 and the cylindrical portion 121 that forms the intake port will be referred to as the "mouth portion"). This mouth portion C is the connection point between the rear end of the cylindrical portion 54 that extends in the cylindrical direction and the inner end of the front wall surface 55 that extends radially outward. A mounting portion 56 (see Figure 4 below for reference numerals) for attaching the liner ring 131 is formed at this corner. The liner ring 131 is cylindrical and is fixed to the mounting portion by press-fitting from the rear side toward the front in the direction of the rotation axis Ax. The cylindrical portion 121 that faces the inner wall surface of the liner ring 131 and forms the intake port of the impeller 120 is formed in a substantially cylindrical shape with an opening at the front end. The outer circumferential wall surface of the cylindrical portion 121 is formed with an inclined surface 22 such that, in cross-sectional view, there is a small gap between it and the inner circumferential surface of the liner ring 131. This is to seal the gap and prevent the liquid present in the high-pressure centrifugal space 62 from flowing back through to the low-pressure suction space 52.

[0022] Figure 4 is an enlarged view of the mouse section C of Figure 3. In the mouse section C of a conventional centrifugal pump 101, a cylindrical section 121 is formed on the inlet side of the impeller 120, and a cylindrical liner ring 131 is arranged opposite the outer circumferential surface 121a of the cylindrical section 121. The liner ring 131 is made of metal and is arranged coaxially with the cylindrical section 121 of the impeller 120 at a predetermined distance d. To attach the liner ring 131, a mounting section 56 is formed at the inner corner of the spiral casing 2. The mounting section 56 has a cylindrical surface 56a on its outer circumference that serves as the surface into which the liner ring 131 is press-fitted, and a disc-shaped abutment surface 56b perpendicular to the rotation axis Ax is formed on its front side.

[0023] During the manufacturing of the centrifugal pump 1, the outer circumferential surface of the cylindrical portion 121, shown by the dotted line, and the inner circumferential surface of the liner ring 131, also shown by the dotted line, are formed to have a gap of distance d. This arrangement substantially obstructs the fluid flow between the suction space 52 and the centrifugal space 62 at the opposing portions, preventing the pressurized fluid from flowing back to the lower-pressure suction port 5 side and improving the efficiency of fluid guidance by the vortex casing 2 towards the discharge port 6. Due to the long-term operation of the centrifugal pump 1, the surface of the mouth portion C near the suction port of the impeller 120 wears down, changing from the initial position shown by the dotted line to the position shown by the solid line. Note that not only the outer surface of the impeller 120 but also other parts (e.g., the inside) wear down, but Figure 4 does not correctly illustrate the wear of other parts. Similarly, the liner ring 131 also wears down 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 this wear, the gap between the liner ring 131' and the cylindrical part 121' becomes large, as shown by d1. An increase in the gap d1 leads to a deterioration in the pressure isolation performance between the high-pressure and low-pressure liquids, making a decrease in the performance of the centrifugal pump 1 unavoidable.

[0024] The centrifugal pump 1 according to this embodiment is configured so that the gap d1 shown in Figure 4 can be returned to its original gap d through disassembly and maintenance. Figure 5 is a vertical cross-sectional view of the centrifugal pump 1 according to an embodiment of the present invention, passing through the rotation axis Ax. The differences from the conventional centrifugal pump 101 shown in Figure 3 are the shape of the mouth portion C of the volute casing 2, the shape of the area around the cylindrical portion 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 portion C is the same as that of the conventional centrifugal pump 101, and the same parts are given the same reference numerals. In addition, although the volute casing 2 may have a slightly different internal structure (the shape of the mounting portion 56 detailed in Figure 6(A)) compared to the conventional volute casing 2, it is substantially the same, so there is no external difference between the centrifugal pumps 1 and 101.

[0025] A cylindrical portion 21, which serves as a liquid intake, is formed at the front end of the impeller 20 in the direction of its rotation axis Ax. The outer surface of the cylindrical portion 21 is a conical inclined surface 22 such that the outer diameter increases linearly from the front to the rear. The inner circumference 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 the liquid flowing inside.

[0026] The liner ring portion 30 is formed by a combination of a liner ring 31 and a spacer 32 provided on its front side. The liner ring 31 is roughly cylindrical, but not perfectly cylindrical; it is a conical inclined surface such that the 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 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.

[0027] Figure 6 shows a liner ring portion 30 according to an embodiment of the present invention, where (A) is an enlarged view of the mouse portion C in Figure 5, and (B) is a perspective view of the liner ring portion 30. The liner ring portion 30 of this embodiment is provided in place of the conventional liner ring 131 (see Figures 3 and 4), and is composed of a spacer 32 and a liner ring 31. Figure 6(B) shows the liner ring portion 30 assembly (as shipped from the factory), and 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 an annular plate material. The liner ring 31 is also an integral cylindrical part of metal formed with the same cross-sectional shape continuously in the circumferential direction. The inner circumferential surface of the liner ring 31 has a slightly cylindrical surface 31a at the front, but the rear side is formed as an inclined surface 31b.

[0028] As can be seen in Figure 6(A), the liner ring 31 is provided on the mounting portion 56, and a spacer 32 is inserted between the abutment surface 56b and the front end surface of the liner ring 31. By providing the spacer 32, the front-rear position of the liner ring 31 can be adjusted. An inclined surface 22 corresponding to the inclined surface 31b of the liner ring 31 is formed on the outer circumference 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 be parallel to each other and spaced at a constant distance d. However, it is not necessary for the two inclined surfaces 22 and the inclined surface 31b to be perfectly parallel; it is sufficient if the smallest 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] mouse The inclined surfaces 31b and 22 of section C are non-contacting parallel surfaces and are formed to be inclined at the same angle θ in a direction intersecting the rotation axis Ax. angleThe magnitude of θ should be such that it intersects the rotation axis Ax at an angle greater than 0° and less than 90°, but preferably it should be an angle greater than 0° and less than 45°, and particularly preferably around 10 to 30°. Furthermore, the centrifugal pump 1 may be shipped from the factory with only the liner ring 31 installed without the spacer 32, and the spacer 32 of appropriate thickness (length in the rotation axis Ax direction) may be installed during disassembly and maintenance after use. Alternatively, the cylindrical surface 31a may not be provided at the front end of the inner circumferential surface of the liner ring 31, and the entire surface from the front to the rear end may be formed by an inclined surface 31b.

[0030] Figure 7 illustrates a method for adjusting the gap of the mouth section C, indicated 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 from the volute casing 2 towards the rear by removing several screws located on the outer circumference of the casing cover 40, and the liner ring section 30 can then be removed. After this removal, the wear condition of the liner ring 31 can be visually inspected, and the degree of wear can be measured using a measuring instrument.

[0031] Figure 7(A) is a partial cross-sectional view showing the state when the liner ring 31 and spacer 32 are removed from the spiral casing 2. The liner ring 31 and spacer 32 are fixed to the mounting portion 56 of the spiral casing 2 by press-fitting. When the first inclined surface 31b of the liner ring 31 wears down after many years of use, the inclined surface 31b recedes relative to the opposing second inclined surface 22, and the gap d widens to d1 (d1>d). To counteract this, the liner ring 31 is replaced with a new part. The liner ring 31 and spacer 32 are removed by moving them backward as shown by arrow 35a using a special tool (not shown).

[0032] Next, the length L1 of the newly installed liner ring 30 (= length of spacer 33 + length of liner ring 31) is calculated by measuring the amount of wear on the cylindrical portion 21 of the impeller 20. To obtain this calculated value, specific points on the inclined surface 22 of the impeller 20, such as the end point on the intake port 5 side and the end point on the discharge port 6 side, are predetermined, the diameter of that portion is measured, and the degree of wear of the impeller 20 is calculated by comparing the measured value with the measurement results from the initial manufacturing stage or the design value.

[0033] Figure 8 shows the process of measuring 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 diameter D of the innermost part of the inclined surface 22 is measured with the inner measuring blades 302 and 303. The measurement position is preferably the diameter of the innermost end of the inclined surface 22, but it may also be measured at another position in the axial direction of the inclined surface 22 using a reference point for measurement.

[0034] Returning to Figure 7, since the liner ring 31 is not reused once removed during the assembly process, measuring the wear on the removed liner ring 31 is not essential. The gap d will have expanded from the initial manufacturing stage by the amount of wear between the impeller 20 and the liner ring, so a new spacer 33 is provided with a plate thickness (= length in the direction of the rotation axis Ax) increased by the amount of wear. A new, unworn liner ring 31 is used adjacent to the spacer 33. The new fixed position of the inclined surface 31b of the liner ring 31 is determined by the plate thickness of the spacer 33 located between the liner ring 31 and the abutment surface 56b of the spiral casing 2. Therefore, by preparing multiple types of spacers 32, 33, etc. with different plate thicknesses as adjustment spacers, it becomes possible to appropriately adjust the relative position of the liner ring 31 with respect to the impeller 20 during disassembly maintenance.

[0035] The method for installing the liner ring 30 involves moving the spacer 33 and liner ring 31 in the forward direction (direction of arrow 35b), opposite to the removal direction 35a shown in Figure 7(A), and press-fitting them into the mounting part 56 toward the spiral casing 2 on the front side of the rotation axis Ax. Figure 9(A) shows the state after these have been press-fitted. In Figure 9(A), because the thickness of the newly installed spacer 33 (distance in the direction of the rotation axis Ax) is greater than that of 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 factory shipment. Therefore, even if the inclined surface 22 of the impeller 20 is worn and the inclined surface 22 is retracted backward in the direction of the rotation axis Ax, it is possible to appropriately adjust the gap d.

[0036] While it has been common practice to use the same material for the impeller 20 and the liner ring 31 in conventional designs, in this embodiment, it is desirable to manufacture the liner ring 31 from a metal that is slightly softer and more easily machinable than the impeller 20, for example, a material with lower hardness. For example, if the material of the impeller 20 is FC200 or SCS13, the material of the liner ring 31 should be CAC406 or CAC902. The shape of the spacers 32 and 33 is ring-shaped with the same outer diameter and minimum inner diameter as the liner ring 31. Furthermore, it is desirable to use a metal with strength equal to 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 deformation or wear of the spacer 32.

[0037] As described above, according to the first embodiment, as a result of the adjustment shown in Figure 7(B), the inclined surface 31b of the liner ring 31 approaches the inclined surface 22 of the opposing part of the impeller 20, making it possible to adjust the gap d to be appropriate. This makes it possible to restore the performance degradation of the centrifugal pump 1 due to long-term use, and thus it is possible to continue using the centrifugal pump 1 without replacing the entire unit after long-term use. The costs required for the continued use of the centrifugal pump 1 are the cost of the parts for the liner ring 31 and spacer 33, and the costs associated with disassembly, replacement work, and adjustment work, which can be kept sufficiently low compared to replacement with a new one, thus realizing an environmentally friendly and eco-conscious centrifugal pump 1. [Examples]

[0038] Figure 9(B) is an enlarged view of the mouse section C of the centrifugal pump 1, showing a second embodiment. In Figure 9(A), multiple spacers of different thicknesses are shown in the direction of the rotation axis Ax. 34 The system was configured to prepare the necessary components and then select and install spacers of appropriate thickness. However, in the second embodiment, multiple spacers 34 of the same thickness were prepared, and the number of spacers interposed was increased or decreased according to the position of the liner ring 31 to be fixed. Spacer 3 4 This ring has the same outer and inner diameters as the liner ring 31. While one thin ring with a thickness of 0.1 mm is sufficient, it is also beneficial to have multiple rings with varying thicknesses, including some with a thickness of 1 mm. This allows for more efficient adjustment of the gap d, which will be discussed later. Spacer 3 4 The material of the spacer 3 shall be a metal with strength equivalent to or greater than that of the liner ring 31. For example, if the material of the liner ring 31 is CAC406 or CAC902, the spacer 3 4 It is desirable to use materials such as FC200 or SUS304 for this. This will result in spacer 3 4Displacement of the liner ring 31 in the direction of the rotation axis Ax due to deformation or wear is reduced. In the state of FIG. 9(B), five thin spacers 34 are interposed between the spacer and the abutment surface 56b. According to the second embodiment, simply preparing a large number of spacers 34 of the same shape enables flexible response to fixing the liner ring 31 at different positions. [Example]

[0039] FIG. 10 is related to a third embodiment of the present invention centrifugal pump enlarged view of the mouse part C in 1A. As shown in FIG. 10(A), compared with the centrifugal pump of Embodiment 1, the centrifugal pump according to the third embodiment differs in that it includes an impeller 20A having a step in the rotation axis Ax direction 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 such that they are separated from the inclined surface 31b toward the discharge port 6 side, and the gap between the impeller 20A and the liner ring 31 is widened. In this way, the inclined surface 22 has a first-step inclined surface 22a and a second-step inclined surface 22b with the end point on the side close to the suction port 5 as a reference point. The gap between the first-step inclined surface 22a on the side close to the suction port 5 and the liner ring 31 is d, and the gap between the end point of the inclined surface 22 on the side close to the discharge port 6 and the liner ring 31 is d3, where the relationship d<d3 is satisfied. However, by reversing the relationship of these steps, the second-step Slope It is also possible to set the gap between the surface 22 and the liner ring 31 as d, and set the gap between the first-step inclined surface 22a on the side close to the suction port 5 and the liner ring 31 as d3.

[0040] Only the surface of the inclined surface 22 of the opposing part of the impeller 20A from the reference point to the first step (in this case, the first inclined surface 22a) forms a narrow gap d with the inclined surface 31b of the opposing liner ring 31. This makes it less susceptible to wear caused by impurities entering the gap d3 on the second inclined surface 22b side, and wear caused by contact between the liner ring 31 and the inclined surface 22 of the impeller 20A due to vibration. There are no specifications regarding the size or number of steps on the inclined surface 22 of the impeller 20A, but functionally, the smaller the size of the steps and the more steps there are, the better. In addition, steps similar to those on 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 each step on the inclined surface of the liner ring 31 should be smaller than the size of each step on 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, which does not form a gap d, will be positioned closer to the opposing inclined surface 22b of the impeller 20A. This reduces the thickness of the spacer 32 required when adjusting the position of the liner ring 31 using the adjustment method described later, and makes it less likely for individual differences in the thickness of each spacer 32 or displacement of the liner ring 31 due to deformation to occur.

[0041] Figure 10(B) shows the same configuration as in Figure 10(A), but with multiple spacers 34 of the same thickness instead of the spacer 33 used in Figure 10(A). The idea is the same as in Embodiment 2 shown in Figure 9(B), in that the number of spacers interposed is increased or decreased according to the front-to-back 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 liner ring and the abutment surface 56b. Using this modified configuration, the liner ring 31 can be fixed to 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 using the same procedure as in Example 1, but the method for determining the amount of wear on the cylindrical portion 21A of the impeller 20A is different. In Example 3, the amount of wear on the impeller 20A is determined by comparing the number of steps on the inclined surface 22 of the impeller 20A with the number of steps at the time of initial manufacturing and the number of steps at the time of disassembly and maintenance, and is determined by the size of each step and the number of steps that have disappeared due to wear. Subsequently, the thickness of the spacer 32 is increased to adjust the wear amount of the inclined surface 22 of the impeller 20A and the angle (θ) of the inclined surface 31b of the liner ring 31 with respect to the rotation axis Ax direction. The position of the liner ring 31 is fixed at a position further back in the rotation axis Ax direction than before the disassembly and maintenance (closer to the impeller 20A), 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 reducing the gap d3 and adjusting the gap d to an appropriate distance.

[0043] In Example 3, due to wear of the impeller 20A caused by impurities, an arbitrary number of steps disappear from the reference point side. Therefore, the inclined surface (22b) of the part of the impeller 20A that is less affected by wear and is located at an arbitrary number of steps from the reference point, which was previously 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 the new liner ring 31 after the gap adjustment. Thus, a more precise gap d can be formed compared to Example 1. [Examples]

[0044] Figure 11 is an enlarged view of the mouse portion C of a fluid device according to the fourth embodiment of the present invention. The centrifugal pump 1B according to embodiment 4 differs from the centrifugal pump 1 of embodiment 1 in that a recess 28 is formed in the inclined surface 22 of the impeller 20B. The recess 28 is a small diameter hole (for example, a few millimeters, equivalent to the smallest drill size) drilled in the opposite direction to the normal direction to the inclined surface 22 of the impeller 20B, and is drilled perpendicular 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 circumference of the cylindrical portion 21B. If the recess 28 is a small hole, for example, with a diameter of about 1 mm, the cylindrical portion 21 B The effect of wear on the inclined surface 22 can be ignored. During maintenance of the centrifugal pump 1B, by measuring the depth from the bottom of the recess 28, which is less affected by wear, to the opening, it becomes possible to calculate the amount of wear on the worn inclined surface 22. For example, if the depth of the recess 28 was 10 mm at the time of factory shipment, and the depth of the recess 28 is measured to be 6 mm during disassembly maintenance after many years of use, the amount of wear on the 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 using the same procedure as in Embodiment 1, but the method for determining the degree of wear of the impeller 20B is different. In Embodiment 4, the depth of the recess 28 formed on the inclined surface 22 of the part facing the impeller 20B is measured and compared with the initial depth or design value to determine the degree of wear of the impeller 20B. A spacer 32 equal to the amount of wear is then placed between the abutment surface 56b and the liner ring 31 to adjust the gap between the inclined surface 31b of the liner ring 31 and the cylindrical part 21B.

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

[0047] Figure 12 is an enlarged view of the mouse portion C of a centrifugal pump 1C according to a fifth embodiment of the present invention. As shown in Figure 12, even if the impeller 20C does not have an inclined surface 22 as shown in Figure 6(A) on the outer circumferential surface of the portion (cylindrical portion 21C) facing the liner ring 31, and only has a surface 27 parallel to the rotation axis Ax direction, the inclined surface 31b of the liner ring 31 is positioned in the direction of the rotation axis Ax direction of the impeller 20 C The gap d can be appropriately adjusted by moving it closer to the surface 27 side. In this case, the inclined surface 31b of the liner ring 31 and the tip corner 27a of the cylindrical part 21C of the impeller 20C are positioned in a way that allows them to contact when the rotation axis Ax direction of the liner ring 31 is shifted. C This constitutes the position of the tip corner 27a from the rotation axis Ax (radius r) of the liner ring 31. 31b The radius of the tip corner 27a is larger than the inclined surface of the liner ring 31 31b The positional relationship is such that it is smaller than the radius of the rear end corner. With this configuration, it is possible to effectively adjust the gap d between the liner ring 31 and the tip corner 27a of the cylindrical portion 21C that faces it.

[0048] As described above using Examples 1 to 5, by partially changing the shape of the cylindrical portion 21 of the impeller 20 to form an inclined surface 22 on the outer circumference, changing the shape of the liner ring 31 to form an inclined surface 31b, and using spacers 32 to 34, etc., 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, the gap can be easily adjusted to the appropriate interval during disassembly and maintenance. It should be noted that the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the invention. [Explanation of Symbols]

[0049] 1. 1A~1C Centrifugal pump 2. Volute casing 3. Screw boss 4 Leg section 5 Suction port 6 Discharge port 7 Main shaft 7a Thin diameter section 7b Female thread section 7c Key 8 Bearing section 9a Shaft seal 9b Bearing 10 Spacer 13, 14 Sensor 19 volts 20, 20A~20C impeller 21 Cylindrical section 2 2. Inclined surface (second inclined surface) 22a First stage inclined surface 22b Second stage inclined surface 2 4 mounting holes 25 Blade 26 Outlet 27a Tip corner 28 Recess 30 Lining section 31 Lining 31a Cylindrical surface 31b Inclined surface (first inclined surface) 31c Outer cylindrical surface 32~34 Spacer 40 Casing cover 41 Screw bolt vinegar 5 1 Flange 52 Suction space 54 Cylindrical section 55 Front wall surface 56 Mounting portion 56a Cylindrical surface 56b Butt surface 61 Flange 62 Centrifugal space 63 Outlet space 101 Centrifugal pump 120 Impeller 121 Cylindrical section 121a Outer surface 125 Blade 127 Front wall 128 Rear wall 131 Liner ring 300 Caliper

Claims

1. An impeller fixed to a main shaft rotated by a drive source, which applies pressure to the fluid radially outward from near the axis as it rotates, A casing that houses the impeller, having a fluid intake port and a discharge port, and having a flow path that guides the fluid pressurized by the impeller toward the discharge port, A fluid device comprising a cylindrical liner ring in the mouth portion of the casing, which faces the impeller with a gap between them, The impeller is arranged in a circumferential direction with multiple blades, each having a front edge connected to a front wall and a rear edge connected to a rear wall. Near the center of the front wall, a cylindrical portion is formed that extends toward the intake port side when viewed in the axial direction and has an opening at its front end. Near the center of the rear wall, a through hole is formed for the main shaft to pass through. The impeller is fixed to the main shaft by bolts attached to the end of the main shaft. The outer circumferential surface of the cylindrical portion of the impeller faces the mouth portion of the casing with the gap described above. A first inclined surface is formed on the liner ring, which is inclined in a direction intersecting the rotation axis direction of the impeller. A second inclined surface is formed on the outer surface of the cylindrical portion facing the liner ring, in a direction that intersects with the rotation axis direction. A spacer is provided between the mounting portion of the liner ring in the casing and the liner ring, which adjusts the size of the gap between the first inclined surface and the second inclined surface by adjusting the mounting position of the liner ring in the axial direction of the main shaft. The fluid device is characterized in that the second inclined surface has a first-stage inclined surface formed closer to the suction port, with the endpoint closer to the suction port as the reference point, and a second-stage inclined surface formed further from the suction port than the first-stage inclined surface, wherein the distance between the first-stage inclined surface and the liner ring is smaller than the distance between the second-stage inclined surface and the liner ring.

2. The fluid device according to claim 1, characterized in that the first inclined surface of the liner ring is formed by a first-stage and a second-stage inclined surface having a step, and the size of the step on the first inclined surface is smaller than the size of the step from the first-stage inclined surface to the second-stage inclined surface on the second inclined surface.

3. The fluid device according to claim 1, characterized in that the first inclined surface and the second inclined surface are formed to be parallel at the same angle when viewed in a cross-section including the axis of rotation.

4. The fluid device according to claim 1, characterized in that the outer circumferential surface of the liner ring has a constant diameter, and an inclined surface is formed on a part or all of the inner circumferential surface in the direction of the rotation axis, wherein the inner diameter increases as it moves away from the suction port side in the direction of the rotation axis.

5. The fluid apparatus according to claim 1, characterized in that a plurality of annular spacers with different thicknesses in the direction of the rotation axis are prepared, and the distance between the mounting portion and the liner ring in the direction of the rotation axis is adjusted by placing one of them between the mounting portion and the liner ring.

6. The fluid device according to claim 1, characterized in that the distance between the mounting portion and the liner ring in the direction of rotation is adjusted by arranging a plurality of annular spacers having the same thickness in the direction of rotation axis between the mounting portion and the liner ring.

7. The fluid apparatus according to claim 1, characterized in that the angle the first inclined surface makes with respect to the principal axis is greater than 0 degrees and less than 45 degrees.

8. The fluid apparatus according to claim 1, characterized in that a non-through hole is formed in a part of the circumferential direction of the second inclined surface of the impeller, in a direction perpendicular to the second inclined surface.

9. An impeller fixed to a main shaft rotated by a drive source, which applies pressure to the fluid radially outward from near the axis as it rotates, A casing that houses the impeller, having a fluid intake port and a discharge port, and having a flow path that guides the fluid pressurized by the impeller toward the discharge port, A method for adjusting the gap in a fluid device, comprising a cylindrical liner ring in the mouth portion of the casing that faces the impeller with a gap between them, The impeller is arranged in a circumferential direction with multiple blades, each having a front edge connected to a front wall and a rear edge connected to a rear wall. Near the center of the front wall, a cylindrical portion is formed that extends toward the intake port side when viewed in the axial direction and has an opening at its front end. Near the center of the rear wall, a through hole is formed for the main shaft to pass through. The impeller is fixed to the main shaft by bolts attached to the end of the main shaft. The outer circumferential surface of the cylindrical portion of the impeller faces the mouth portion of the casing with the gap described above. A first inclined surface is formed on the liner ring, which is inclined in a direction intersecting the rotation axis direction of the impeller. A second inclined surface is formed on the outer surface of the cylindrical portion facing the liner ring, in a direction that intersects with the rotation axis direction. On the second inclined surface, using the endpoint closest to the suction port as the reference point, a first-stage inclined surface is formed closer to the suction port, and a second-stage inclined surface is formed further from the suction port than the first-stage inclined surface. When the casing is disassembled, the amount of wear on the first inclined surface of the second inclined surface of the impeller is measured. A method for adjusting the gap in a fluid device, characterized by adjusting the size of the gap between the first inclined surface and the second inclined surface by providing a spacer between the mounting portion of the liner ring in the casing and the liner ring, in accordance with the amount of wear, for adjusting the mounting position of the liner ring in the axial direction of the main shaft.

10. The gap adjustment method for a fluid device according to claim 9, characterized in that the amount of wear of the impeller during gap adjustment is determined by measuring whether or not the step difference from the first inclined surface to the second inclined surface of the second inclined surface of the impeller has disappeared.

11. A non-through hole is formed in a part of the circumferential direction of the second inclined surface, in a direction perpendicular to the second inclined surface. The gap adjustment method for a fluid device according to claim 9, characterized in that the amount of wear of the impeller during gap adjustment is determined by measuring the depth of the remaining non-through hole and comparing it with the initial depth.

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