Fluid device and centrifugal pump system using the same

Abstract

To provide a fluid device in which while an external pipe on an inflow side and a flange of a casing are connected, a casing body part can be separated from the external pipe.SOLUTION: A fluid device 101 comprises a casing 102 comprising a suction port 115 for sucking fluid in an axial direction, and a discharge port 106 for discharging it in a radial direction, and guides liquid to the discharge port 106 by rotating an impeller 30 fixed to a rotating shaft 7. A suction part 110 including the suction port 115 of the casing 102 and a mouth part can be separated from a main body part. The suction part 110 is fixed to a casing body part 120 by tightening bolts. The size of an opening 121 of the casing body part 120 is made larger than the diameter of the impeller 30.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to fluid equipment such as a centrifugal pump, and in particular to a casing in which a portion (suction portion) forming a suction port and a mouth portion is detachable from the main body of the casing. [Background technology]

[0002] In today's society, where measures to combat environmental issues such as global warming are urgently needed, not only is product quality essential, but environmentally conscious manufacturing is also required. Traditionally, in the pump industry, which handles fluid equipment, it was common for old pumps to be discarded and replaced with new ones. In recent years, companies have devised a remanufacturing method in which they collect, repair, and reuse old pumps, considering their impact on the environment. When the applicant checked the actual installation status of fluid equipment, he found that one user had wrapped heaters and insulation around the piping and pump flange to prevent freezing, making it difficult to remove the fluid equipment from its installed state. Another user's piping and pump flange were welded together, making removal and recovery of the fluid equipment difficult, hindering repair and reuse of the fluid equipment.

[0003] Patent Document 1 discloses an example of a conventional fluid equipment (centrifugal pump) in which a rear portion can be separated from the integrally constructed casing main body, and the rear wall surface of the casing that supports the bearing can be separated. This separable structure makes it possible to attach an impeller inside the casing. Patent Document 2 discloses a pump flange provided near the suction port that can be separated from the main casing body.

[0004] The structure of a conventional fluid equipment such as that shown in Patent Document 1 will now be briefly described with reference to FIGS. 12 to 15. FIG. 12 is a perspective view of a centrifugal pump 1, which is one example of fluid equipment. The centrifugal pump 1 uses the rotational force of a drive source such as a motor to drive a rotary shaft 7, causing an impeller (described later in FIG. 13 ) fixed to the rotary shaft 7 to rotate at high speed, thereby drawing in a fluid in the axial direction through a suction port 5 and discharging the fluid at high speed through a discharge port 6. The centrifugal pump 1 has a casing 2 having an internal space formed in a spiral shape. The casing 2 is manufactured by integral molding of metal, and the suction port 5 is located forward in the direction of the rotation axis Ax, and the discharge port 6 is located radially upward in a direction perpendicular to the direction of the rotation axis Ax. A mounting flange 16 is provided around the suction port 5, and eight through-holes 17 formed in the flange 16 are used to connect external piping (not shown) by bolting. Similarly, a mounting flange 18 is formed around the discharge port 6, and four through holes 19 formed in the flange 18 are used to connect external piping (not shown) by bolting. The centrifugal pump 1 is expected to handle water primarily, but it may also be used to transport liquids other than water. Legs 4 are provided on the underside of the casing 2. The legs 4 are members for bolting the centrifugal pump 1 to a floor, a pedestal, or the like, and have through holes 4a and 4b formed therein for passing screws or bolts (not shown). A bearing 60 is attached to the rear side of the casing 2.

[0005] FIG. 13 is an exploded perspective view of a conventional centrifugal pump 1. A flow path for fluid flow is provided inside the casing 2, and a circular opening 25 for inserting the impeller 30 is formed at the rear side. The opening 25 is closed by the rear cover 40. The rotating shaft 7 is a one-piece metal molded product that is long in the front-to-rear direction. The impeller 30 is fixed to the front end of the rotating shaft 7, which extends into the inside of the casing 2 through a through-hole 45 in the rear cover 40. To rotatably support the rotating shaft 7 while it is inserted through the rear cover 40, a bearing unit 60 for fixing a plurality of bearings 63 and 65 (described later) is provided at the rear side of the rear cover 40. The bearing unit 60 is fixed to the rear cover 40 with bolts (not shown) and has a flange 62, which has four through-holes 62a formed in the flange 62.

[0006] FIG. 14 is a vertical cross-sectional view of a conventional centrifugal pump 1, taken along the rotation axis Ax. The flow path from the suction port 5 to the impeller 30 in the direction of the rotation axis Ax has a constant inner diameter, while the spiral-shaped space (23-24) extending upward to the discharge port 6 is formed so that the cross-sectional area of ​​the flow path gradually increases, and the casing 2 is sometimes referred to as a "volute casing." Fluid supplied to the suction port 5 from an inlet pipe (not shown) flows into the volute casing 2 in the direction of arrow 13 (rearward in FIG. 1) toward the front of the rotation axis Ax and is drawn into the internal space of the impeller 30 through a cylindrical suction port 32 at the front of the rotating impeller 30. The fluid drawn into the impeller 30 flows radially outward while being compressed and accelerated by the blades 33 and is discharged from the discharge port 35 into the centrifugal spaces 21 and 22 inside the volute casing 2.

[0007] The centrifugal spaces 21 and 22 are spaces formed continuously in the circumferential direction, and for convenience, the upper space is designated as the centrifugal space 21 and the lower space is designated as the centrifugal space 22, with two reference numerals given to them. In this specification, the portions of the internal space of the volute casing 2 that contact the discharge port 35 of the impeller 30 are defined as the centrifugal spaces 21 and 22, and the spiral flow passages that guide the liquid from the centrifugal spaces 21 and 22 to the discharge port 6 are designated as 23 and 24. The centrifugal spaces 21 and 22 and the flow passages 23 and 24 form the "flow path" for the liquid discharged from the impeller 30. The fluid accelerated to high pressure by the high-speed rotation of the impeller 30 is guided circumferentially along the inner wall surface of the volute casing 2 in the centrifugal spaces 21 and 22, guided to the discharge port 6 via the flow passages 23 to 24, and discharged in the direction of arrow 14. In this way, the space formed by the flow passages 23 and 24 is part of a spiral flow path, and is formed to guide the fluid toward the discharge port 6. A circular opening 25 on the rear side of the casing 2 is closed by a rear cover 40. The rear cover 40 is detachably fixed with a plurality of bolts 46, and the impeller 30 can be inserted into the casing 2 with the rear cover 40 removed.

[0008] The impeller 30 is a rotating body on which a plurality of blades 33 are formed at equal intervals in the circumferential direction. The front edges of the blades 33 are connected to the front wall 31, and the rear edges are connected to the rear wall 34. The blades 33 are integrally manufactured, for example, by die-casting metal. The action of the blades 33 rotating at high speed compresses and accelerates the fluid present between the front wall 31 and the rear wall 34 of the impeller 30. The fluid is guided near the outer periphery of the impeller 30 at high speed and discharged through the outlet 35 into the centrifugal spaces 21 and 22. A flange 43 extending radially outward is formed on the rear side of the mounting surface 41a of the rear cover 40. A seal material 26 is interposed between the flange 43 and the rear cover 40 to prevent water leakage from the internal space of the casing 2 to the outside. The impeller 30 is fixed to the front end (front end) of the rotating shaft 7 with bolts 9. The rotating shaft 7 is rotatably supported by a bearing portion 60 via bearings 63 and 65.

[0009] A narrow labyrinth gap is formed between the inner rear end (near arrow 20) of the cylindrical portion 10 on the suction side of the volute casing 2 and the outer circumferential surface of the front end of the impeller 30 (the portion indicated by arrow 36). The portion forming this narrow gap is referred to as the "mouth portion" in this specification. The mouth portion is formed to seal against backflow of liquid present in the high-pressure centrifugal spaces 21 and 22, particularly liquid present in front of the front wall 31 of the impeller 30, through the gap in the mouth portion toward the low-pressure space near the suction port 32.

[0010] FIG. 15 is an overall view of a conventional centrifugal pump 1 and drive unit 90. The centrifugal pump 1 is fixed to a base 95 by legs 4 and an L-shaped bracket 68. Legs 93 of the drive unit 90 are also fixed to the base 95. Couplings 8 and 92 are attached to the rotating shaft 7, which protrudes rearward from the bearing unit 60 of the centrifugal pump 1. The couplings 8 and 92 are connected to an output shaft 91 of a drive unit 90, such as a motor. The coupling 8 on the pump side and the coupling 92 on the drive unit 90 side may be fixed together using bolts and nuts (not shown) inserted through through-holes (not shown) formed parallel to the rotation axis Ax. However, any connection method may be used, and any known method may be used. Fluid, such as water, flowing in through the suction port 5 is pressurized by the impeller 30, which rotates at high speed inside the casing 2, and then supplied from the discharge port 6 to a location where the fluid is needed via piping (not shown). [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 2024-877 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-20498 Summary of the Invention [Problem to be solved by the invention]

[0012] In Patent Document 1, a large portion of the rear wall surface of the casing on the drive unit side (the side opposite the suction unit as viewed in the direction of the rotation axis Ax), which defines the rotation space of the impeller, is configured to be separable. The separable casing cover is bolted to the casing, and the casing opening is circular and larger than the impeller, allowing the casing cover to be removed rearward along with the impeller. With this structure, if both the suction flange and the discharge flange are firmly fixed to external piping, it becomes difficult to remove and recover the centrifugal pump's main body (particularly the casing 2). Furthermore, in cases where measuring instruments, insulation equipment, etc. are installed at the location where the centrifugal pump is fixed to the external piping, it is difficult to reuse the centrifugal pump's main body. Therefore, the inventors considered it desirable to facilitate the reuse of centrifugal pumps by making the main part of the casing easily removable, regardless of the state of piping fixation or whether any equipment is attached to the piping connection.

[0013] In Patent Document 2, the pump flange has a suction side and a discharge side, and the portion near the suction side is designed to be disassembled in the direction of the rotation axis Ax. In Patent Document 2, the disassembled suction casing is fastened with screws via bolt holes 415b additionally formed in flange 411 around the suction port. Therefore, it was found that the centrifugal pump of Patent Document 2 has a problem in that the suction casing portion cannot be removed from the pump casing main body while the suction side piping and flange 411 remain connected.

[0014] An object of the present invention is to provide a fluid device in which the casing main body can be separated from the external piping while the external piping on the inlet side remains connected to the flange on the fluid device side. Another object of the present invention is to improve the dividing structure of the casing near the suction port of the fluid equipment, thereby facilitating the checking of the internal condition of the casing and replacement of the impeller, as well as facilitating the recovery, repair, or reuse of the main body of the fluid equipment. [Means for solving the problem]

[0015] Representative features of the invention disclosed in this application are as follows. According to a feature of the present invention, the present invention is applied to a fluid equipment including an impeller fixed to a rotating shaft rotated by a drive unit and adapted to suck in and discharge a fluid, and a casing that houses the impeller and has an inlet port that sucks in the fluid in the axial direction and an outlet port that discharges the fluid pressurized by the impeller. The casing of the fluid equipment has a flow path that guides the liquid pressurized by the impeller and discharged to the outlet port while rotating it in the circumferential direction, and a mouth portion is formed between the impeller and the casing, facing each other with a minimal gap. The suction portion, which extends from the inlet port to the mouth portion of the casing, is configured to be detachable from the casing main body. A circular opening is formed in the front side of the casing main body, the size of which is larger than the diameter of the impeller.

[0016] According to another feature of the present invention, the suction section comprises a first flange for connecting the suction port to an external pipe, a wall surface for closing the opening of the casing main body, a second flange provided on the outer periphery of the wall surface and having a through hole for fixing to the casing main body, and a duct connecting the first flange to the wall surface. The casing main body is formed with a mounting surface that contacts the second flange, and the second flange is fixed to the casing main body by a plurality of screw means. The mouth section comprises an inner diameter surface formed on the inside of the wall surface and an outer diameter surface formed outside the suction port of the impeller and facing the inner diameter surface without contacting it.

[0017] According to yet another feature of the present invention, the second flange has a through hole, and a mounting surface with a threaded hole is formed radially outward of the mounting surface of the casing body. The suction section is screwed into the threaded hole by a plurality of bolts oriented parallel to the axial direction of the rotating shaft through the through hole. In another embodiment, the second flange has a cylindrical surface and a plurality of protrusions partially protruding radially outward from the cylindrical surface, and through holes are formed in the protrusions. The outer peripheral surface of the casing body may have a body-side flange protruding radially outward and formed with a second through hole, and the suction section may be fixed to the casing body by a stud bolt that passes through the protrusions and the body-side flange and has a central axis oriented parallel to the rotating shaft, and a nut.

[0018] According to still another feature of the present invention, the fluid equipment described above is used, and a connecting pipe for connecting to an external pipe is provided between the discharge port of the fluid equipment and a flange of a pipe to a liquid supply destination. The system is configured to operate the fluid equipment using a drive device that rotates the rotating shaft of the fluid equipment, and a companion flange is provided between the discharge port of the fluid equipment and the connecting pipe, and the rotating shaft of the fluid equipment and the output shaft of the drive device are connected by a coupling via a removable spacer. [Effects of the Invention]

[0019] According to the present invention, the suction section is formed with a second flange section separate from the inlet-side first flange section, allowing the suction section to be separated from the opening of the casing main body. This allows the casing main body to be separated from the inlet-side piping and the suction section while the inlet-side piping and the first flange section remain attached. In particular, by separating the section that fastens the first flange section to the inlet-side piping from the section that fastens the second flange section to the casing main body, the bolts for each section can be attached and detached independently. According to the present invention, the suction section can be separated from the casing main body regardless of whether the inlet-side piping and the first flange section are joined or separated, significantly improving the maintainability of fluid equipment. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view of a centrifugal pump 101 according to a first embodiment of the present invention. [Figure 2] FIG. 1 is an exploded perspective view of a centrifugal pump 101 according to a first embodiment. [Figure 3A] 1 is a vertical cross-sectional view of a centrifugal pump 101 according to a first embodiment. [Figure 3B] 3B is a partially enlarged view of the fitting portion between the suction portion 110 and the casing main body portion 120 in FIG. 3A. FIG. [Figure 4] 1 is an overall view of a centrifugal pump 101 and a driving device 90 according to a first embodiment. [Figure 5] 1A to 1C are perspective views showing a procedure for removing the centrifugal pump 101 of the first embodiment (part 1). [Figure 6] 10 is a perspective view (part 2) showing the procedure for removing the centrifugal pump 101 of the first embodiment. FIG. [Figure 7] FIG. 2 is a perspective view of a centrifugal pump 201 according to a second embodiment of the present invention. [Figure 8] FIG. 10 is a vertical cross-sectional view of a centrifugal pump 201 according to a second embodiment. [Figure 9] FIG. 10 is a vertical cross-sectional view of a centrifugal pump 201A according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a vertical cross-sectional view of a centrifugal pump 301 according to a fourth embodiment of the present invention. [Figure 11] FIG. 10 is a perspective view of a casing main body 120 and a connecting pipe 80A of a centrifugal pump 101 according to a fifth embodiment of the present invention. [Figure 12] FIG. 1 is a perspective view of a conventional centrifugal pump 1. [Figure 13] FIG. 1 is an exploded perspective view of a conventional centrifugal pump 1. [Figure 14] FIG. 1 is a vertical cross-sectional view of a conventional centrifugal pump 1 taken along a line passing through a rotation axis Ax. [Figure 15] FIG. 1 is an overall view of a conventional centrifugal pump 1 and a drive unit 90. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following drawings, the same parts are given the same reference numerals, and repeated explanations will be omitted. In addition, in this specification, the front, back, left, right, and up and down directions will be described as directions shown in the drawings. [Example]

[0022] FIG. 1 is a perspective view of a centrifugal pump 101 according to a first embodiment of the present invention. The centrifugal pump 101 shown in FIG. 1 differs from a conventional centrifugal pump 1 in the divided structure of the casing 102. The casing 102 is divided into a front side (suction section 110) as viewed from a front wall surface 111 in the direction of the rotation axis Ax. In other words, the suction section 110, in which a fluid suction port 115 is formed, is detachably formed in a main body portion (casing main body 120) of the casing 102. The configuration of the rear portion (rear cover 40, bearing section 60) of the casing main body 120 and the shape of the vicinity of the upper discharge port 106 (see FIG. 2 for the reference numerals) are the same as those of the conventional centrifugal pump 1 shown in FIGS. 12 to 15.

[0023] The centrifugal pump 101 of this embodiment is configured as a single-suction, single-stage volute pump and has a volute-shaped casing 102 that defines a space (centrifugal space) in which the impeller 30, which will be described later with reference to FIG. 2, rotates. The casing 102 is provided with a suction port 115 for drawing in fluid from the front to the rear along the rotation axis Ax, and a discharge port 106 (see FIG. 2 for the reference numeral) for discharging fluid in one direction away from the rotation axis Ax, in this case, upward. A first flange 116 for connecting to external piping is formed around the suction port 115. Eight through-holes 117 are formed in the flange 116 at equal intervals around the periphery. Similarly, a flange 107 with through-holes is formed around the discharge port 106 (see FIG. 2 for the reference numeral).

[0024] In the perspective view of FIG. 1, a connecting pipe 80 having a short length in the flow path direction is provided between the discharge-side flange 107 and an external pipe (for example, pipe 55 shown in FIG. 5). The connecting pipe 80 is an accessory or a separately sold part of the centrifugal pump 101 and is not included in the terms "centrifugal pump" and "fluid equipment" used in this specification. FIG. 1 shows the connecting pipe 80 in contact with the discharge-side flange 107 of the centrifugal pump 101, but does not show the bolts and nuts that secure the four through holes 84 (see FIG. 3A, described later, for the state in which the flange 107 and flange 83 are connected). In this embodiment, the liquid handled by the centrifugal pump 101 is primarily assumed to be clean water, but it is not limited to clean water and may be other liquids.

[0025] A through-hole (not visible in FIG. 1 ) is formed in the rear side of the casing 102, through which the rotating shaft 7 passes, and the rotating shaft 7 is disposed so as to extend from the front to the rear through the through-hole. A bearing 60 is provided coaxially with the rotating shaft 7 to rotatably support the rotating shaft 7. Legs 4 are provided on the underside of the casing 102, and the casing 102 is fixed to an installation surface such as a base so that the rotating shaft 7 faces horizontally. Therefore, the rotation axis Ax of the casing 102 is horizontal. The legs 4 are fixing devices for bolting the centrifugal pump 101 to a floor, pedestal, or the like. They extend from the lower right and left sides of the casing, respectively, and have installation surfaces parallel to the installation surface. Through-holes 4a and 4b are formed in the installation surfaces of the left and right legs 4, respectively, for passing screws or bolts (not shown) therethrough.

[0026] FIG. 2 is an exploded perspective view of the centrifugal pump 101 of FIG. 1. The casing 102 of the centrifugal pump 101 is mainly composed of a casing main body 120 that surrounds the impeller 30, a removable suction section 110 that draws fluid into the casing main body 120, and a discharge section with a discharge port 106 for discharging the fluid from the casing main body 120. The casing 102 can be manufactured by casting a metal such as cast iron, but may also be manufactured from other materials. The rear wall surface (rear wall surface 41) of the casing 102 on the rear side (drive unit side) is formed so as to be separable by a rear cover 40. The impeller 30 is rotatably supported within a centrifugal space defined by the casing 102. The impeller 30 is fixed to the tip of a rotating shaft 7 that penetrates the rear cover 40. The rotating shaft 7 extends rearward from the internal space of the casing 102 and protrudes rearward through a bearing 60.

[0027] An opening 121 is provided on the front side surface of the casing main body 120 relative to the rotation axis Ax, and an opening 125 is provided on the rear side surface. The front opening 121 is closed by attaching the suction part 110. That is, in the centrifugal pump 101 of this embodiment, the following components are separable from the main body portion of the casing 102 (the casing main body 120): the pipe line part 114 that forms a flow path from the suction port 115 to the impeller 30 on the front side (opposite the drive part side) of the casing 102; the first flange 116 formed on the front side of the pipe line part 114; most of the front wall surface 111; and the second flange formed on the outer side of the front wall surface 111.

[0028] The first flange 116 of the suction section 110 extends radially outward from the outer edge of the suction port 115, and has the same shape as the flange 116 of the conventional centrifugal pump 1 shown in FIG. 12. The portion forming the front wall surface 111 is annular with a through hole formed in the center, and the front wall surface 111 and the first flange 116 are connected by a short pipe line 114. A cylindrical wall 112 is formed on the outer edge of the front wall surface 111, and a second flange 113 is provided extending radially outward from the front end of the cylindrical wall 112. The rearward portion of the suction section 110 beyond the pipe line 114 is formed with the front wall surface 111 closing the portion inside the opening 121 of the casing 2, the opposing cylindrical wall 112 formed on the outer periphery of the front wall surface 111, and the flange 113 extending radially outward from the front end of the cylindrical wall 112. Flange 113 is formed so that eight circumferential locations further extend partially in the radial direction, and through holes 113a are formed in the extending portions. Through holes 113a are used to attach bolts 129 (see Figures 3A and 3B described below). Sealing material 109 is interposed between the surfaces where main body portion 120 and suction portion 110 are joined.

[0029] An opening 125 is formed at the rear side of the centrifugal pump 101, and the impeller 30 is inserted into the inside of the casing main body 120 from behind through the opening 125. The opening 125 is closed by a rear cover 40. The rear cover 40 is a common part with the conventional centrifugal pump 101 shown in Figures 12 to 14. An abutment surface 126 is formed at the outer edge of the rear opening 125 of the casing main body 120, and screw holes are formed in the protrusions at multiple locations around the periphery.

[0030] The impeller 30 is a rotating body on which a plurality of blades 33 are formed, and the plurality of blades 33 are provided at equal intervals in the circumferential direction between a front wall 31 and a rear wall 34. An intake port 32 is formed around the rotation axis 7 of the front wall 31. The blades 33 are integrally manufactured by, for example, metal die casting. The action of the blades 33 rotating at high speed compresses and accelerates the fluid present between the front wall 31 and the rear wall 34 of the impeller 30, and the fluid is guided near the outer periphery at high speed and discharged from an outlet 35 into the centrifugal spaces 21, 22 (see FIG. 3A described below).

[0031] The casing body 120 defines a space in which the impeller 30 rotates and forms a spiral-shaped flow path when viewed from the direction of the rotation axis Ax. An outlet port 106, which is the outlet of the spiral flow path, is formed in the upper portion of the casing body 120. A third flange 107 with a through-hole 108 is formed around the outlet port 106. The outlet port 106 and flange 107 are integrally molded with the casing body 120. A connecting pipe 80 is connected downstream of the flange 107 in the liquid flow direction. The connecting pipe 80 is a short, straight pipe (straight pipe 81) with flanges 83 and 86 attached to both ends. The connecting pipe 80 is an additional component provided to facilitate disassembly and removal of the centrifugal pump 101 after installation. In the example shown in FIG. 2, a sealant 170 is interposed between the flange 107 and flange 83. Sealing material 170 is provided to prevent fluid leakage from the joint between flanges 107 and 83, and a known gasket, for example, can be used. Pipe 55 (see FIG. 5 described below) leading to the fluid supply destination is connected to the downstream side of the fluid flow (upper side in FIG. 1) of opening 85 provided on the inside of flange 86. Flange 86 has the same shape as flange 107 or a compatible shape, and has four through holes 87 formed therein.

[0032] FIG. 3A is a vertical cross-sectional view of a centrifugal pump 101 of this embodiment. The impeller 30, rear cover 40, bearing unit 60, and rotating shaft 7 are composed of the same parts as those of the conventional centrifugal pump 1 shown in FIGS. 12 to 15. The impeller 30 is fixed to the tip (front end) of the rotating shaft 7 with a bolt 9. A key is formed on the rotating shaft 7 side, and a corresponding key groove is formed on the impeller 30 side, and they are connected to each other in a state where they do not rotate freely. The method of supporting the rotating shaft 7 on the bearing unit 60 is arbitrary, and not only bearings 63 and 65 such as ball bearings, but also other bearing means may be used.

[0033] The suction section 110 is fixed to the casing main body 120 with a plurality of bolts 129 in a state where it is attached so as to close the opening 121 of the casing 102. This separation structure makes it possible to separate the suction section 110 from the casing main body 120 by removing the bolts 129. The size of the opening 121 is made slightly larger than the diameter of the impeller 30. Due to the size of this opening 121, by removing the bolts 9 while the rear cover 40 remains attached, the impeller 30 can be attached to or detached from the rotary shaft 7 from the opening 121 side.

[0034] The fluid flows into the suction section 110 of the casing 102 in the same axial direction as the rotation axis Ax, and the direction of the fluid flow into the suction port 32 of the impeller 30 is also the same as the rotation axis Ax. Centrifugal spaces 21 and 22 are formed near the outer edge of the impeller 30 inside the casing 102 to guide the fluid discharged from the discharge port 35 in the radial and circumferential directions, and further, flow passages 23 and 24 are formed to allow the fluid to flow from the centrifugal spaces 21 and 22 toward the discharge port 106. The flow passages 23 and 24 are spiral spaces whose cross-sectional area gradually increases downstream. From the discharge port 106, the fluid flows to its destination through a straight pipe 81 with the same opening diameter.

[0035] Because the pressure inside the centrifugal spaces 21, 22 is higher than the pressure near the suction port 32, a mouth section is formed to prevent backflow of liquid from the centrifugal spaces 21, 22 toward the upstream side of the suction port 32. The mouth section is a portion of the impeller 30 and the suction section 110 where the distance between the adjacent portions is particularly narrow, and is composed of a pair of a mouth section (inner diameter surface 119) on the suction section side and a mouth section 36 on the impeller section side. The inner diameter surface 119 is formed by enlarging the inner diameter of a portion of the inner wall surface at the connection between the duct section 114 and the front wall surface 111, forming it into a cylindrical shape. The mouth section 36 on the impeller 30 side is formed outside the suction port 32 and is an outer diameter surface formed into a cylindrical shape that faces the inner diameter surface 119 without contacting it. Both when the impeller 30 is rotating and when it is stopped, the mouth section 36 and the inner diameter surface 119 are separated by a small distance, and a non-contact state is maintained. As used herein, the term "outer diameter of the mouth" refers to the diameter of the inner diameter surface 119.

[0036] Casing body 120 and suction section 110 can be separated at a mating portion defined by cylindrical opposing surfaces 112a, 122 of a fixed diameter, with opposing surface 122 facing the outer periphery of inner opposing surface 112a. FIG. 3B is a partially enlarged view of this mating portion separated. In FIG. 3B, a second flange 113 is formed radially outward from the front end of cylindrical wall 112, with through holes 113a formed therein for passing bolts 129. A plurality of screw holes 124 for threading with bolts 129 are formed in mounting surface 123 of casing body 120. Each screw hole 124 has a female thread. The opposing surfaces fastened by bolt 129, i.e., the rear surface (mounting surface 113b) of flange 113 and mounting surface 123 of casing body 120, may have a width W between the inner and outer diameters of the opposing surfaces of at least about 5 mm.

[0037] The flange 113 may be formed in an annular shape, or the inner circumferential portion of the annular flange may be formed with multiple locations extending radially outward, with through-holes 113a formed at the extending locations. Screw bosses 123a are also formed on the casing body 120 corresponding to the locations of the through-holes 113a. This widening of the radial and circumferential dimensions only around the through-holes 113a is preferable from the perspective of reducing material costs. The through-holes 113a and the screw holes 124 may be positioned in corresponding positions. However, arranging them at equal intervals on the same arc so as to be point-symmetric or rotationally symmetric about the rotation axis Ax can more reliably prevent water leakage. Furthermore, a groove 122a for installing a sealant 109 (see FIG. 2) is provided around the entire circumference of the opening 121 (see FIG. 2) at the intersection of the mating portions. In this embodiment, the groove 122a is provided at the corner of the opening 121 of the casing body 120, but it may be provided on the mounting surface 113b side facing the opening 121 depending on the shape of the fitting portion.

[0038] Returning to Figure 3A, connecting pipe 80 is a short pipe with flanges 83, 86 at both ends, each flange having a shape similar to that of flange 107 of conventional casing body 120. One flange 83 faces flange 107 of casing body 120 and has a plurality of through holes 84. The facing through holes 84, 108 are located in corresponding positions. Connecting pipe 80 can be connected without leaks by sandwiching sealant 170 between flange 107 of casing body 120 and flange 83 of connecting pipe 80, passing bolts 71 through the corresponding through holes 84, 108, and fastening them with nuts 72.

[0039] Casing body 120 and suction section 110 are connected without leaks by providing sealant 109, inserting the mating parts in the axial direction, and fastening them with bolts 129 that pass through flange 113, thereby forming a flow path space that includes the mouth section (36, 119) and front wall surface 111. If the mating part between casing body 120 and suction section 110 is configured with through holes and screw holes in this way, centrifugal pumps with different performance can be realized by preparing different types of suction parts with different shapes of front wall surface 111 and different types of impellers.

[0040] In this embodiment, the casing main body 120 and the suction section 110, and the casing main body 120 and the connecting pipe 80 may be respectively fixed using clamps or snap locks instead of bolts and nuts, but from the viewpoint of preventing water leakage, fixing by screw means using bolts and nuts is the most effective. In this embodiment, "screw means" is broadly defined as any means for fixing by threaded engagement of a screw thread and a screw groove, and fixing means using some kind of screw groove, such as a combination of a bolt and a female screw hole formed on the side of the casing main body 120, a combination of a bolt and a nut, a combination of a stud bolt and a nut, or a combination of a flat head screw and a female screw hole, is also included in the scope of "screw means".

[0041] The bearing unit 60 is provided to rotatably support the rotating shaft 7 and is fixed to the rear wall surface 41 of the casing 102. The bearing unit 60 houses two bearings 63 and 65 inside a bearing case 61 consisting of a large-diameter cylindrical portion at the front and a small-diameter cylindrical portion at the rear. The bearing case 61 is manufactured by integral metal molding, and has a mounting flange 62 formed at the front opening. The flange 62 is fixed to the rear cover 40 with bolts 67 through through holes provided at multiple locations around the circumference of the flange 62. The outer ring of the bearing 63 is fixed to the inner circumferential surface of the bearing case 61, and the bearing 65 is fixed to the rear opening of the bearing case 61 via a bearing holder 66. An auxiliary fixing bracket (here, an L-shaped bracket 68) is connected to the underside of the bearing case 61 to stably hold the bearing unit 60 when the centrifugal pump 101 is installed. The L-shaped bracket 68 is fixed to a mounting rib 64 formed on the underside of the bearing case 61 with bolts 69. The lower flat portion of the L-shaped metal fitting 68 is fixed to the base 95 shown in FIG.

[0042] The rear cover 40 is fixed to the casing main body 120 by a plurality of bolts 46. As can be seen from the cross-sectional view of Fig. 3A, the diameter of an opening 125 on the rear side of the casing main body 120, for attaching the rear cover 40, is formed to be sufficiently larger than the diameter of the impeller 30. This is so that when the rear cover 40 is removed, the impeller 30 can also be removed from the opening 125.

[0043] FIG. 4 is a side view showing the overall configuration of a centrifugal pump system comprising a centrifugal pump 101 and a drive unit 90 according to this embodiment. In this specification, the entire configuration, including the centrifugal pump 101 and the surrounding components such as the drive unit 90 and connecting pipe 80, is referred to as the "centrifugal pump system." The centrifugal pump 101 is installed on a base 95, such as a floor or a mounting stand, and is fixed with bolts (not shown) that pass through the through-holes 4a and 4b (see FIG. 1) in the legs 4. The rotating shaft 7 of the centrifugal pump 101 is connected to the drive unit 90 via a spacer 190 of a certain thickness interposed between the couplings 8 and 92. The drive unit 90 is, for example, an electric motor. However, it is not limited to electric motors; various known power sources other than engines can be used as long as they can transmit rotational force to the rotating shaft 7. The thickness (length T1) of the spacer 190 in the rotating shaft direction is preferably at least half the outer diameter D2 of the flanges 83 and 86 of the connecting pipe 80. If the length T1 is sufficiently secured, the centrifugal pump 101 can be easily removed during inspection and maintenance.

[0044] FIG. 5 is a perspective view showing the procedure for removing the centrifugal pump 101 from the inlet pipe 50 and the discharge connecting pipe 80 from the state shown in FIG. 4 . In FIG. 5 , the size of the spacer 190 is different from that shown in FIG. 4 . The length T2 of the spacer 190 is equal to or greater than the outer diameter D2 of the flanges 83 and 86, but the length T2 is determined depending on the installation location and the configuration of the base 95. The centrifugal pump 101 is removed when no fluid is flowing. The suction section 110 and the piping 50, and the casing main body 120 and the connecting pipe 80 are secured with bolts and nuts (not shown). In the conventional centrifugal pump 1 shown in FIGS. 12 to 14 , the only way to separate the piping 50 from the casing 2 was to remove the flange 51 of the piping 50 and the flange 16 on the casing 2 side. In addition to the same removal method as in the conventional embodiment, this embodiment also allows the casing main body 120 to be separated from the suction section 110 while the flanges 51 and 116 remain connected.

[0045] First, (1) remove the eight bolts 129 (see FIG. 3A) that secure the suction section 110 of the casing 102 to the casing main body 120, thereby releasing the connection between the suction section 110 and the casing main body 120. Next, (2) remove the bolts 71 and nuts 72 (see FIG. 3A) that are inserted through the through holes in the flanges 107 and 83, thereby releasing the connection between the flange 107 of the casing main body 120 and the flange 83 of the connecting pipe 80. Next, (3) remove the bolts (not shown) that are inserted through the through holes 4a and 4b in the leg 4, thereby releasing the connection between the leg 4 and the base 95. Finally, (4) remove the spacer 190 as shown by the arrow 191 to secure a space between the centrifugal pump 101 and the drive unit 90. The connection methods for the spacer 190 and the coupling 8, and the spacer 190 and the coupling 92, as well as how they are fixed and removed, are arbitrary. The steps (1) to (4) can be performed in any order, so you can change the order of the steps.

[0046] FIG. 6 is a perspective view showing the removal procedure following FIG. 5 . As shown in FIG. 6 , the casing body 120, from which the suction portion 110 has been removed, is moved by pulling it out toward the drive unit (rearward) along the rotation axis Ax, as indicated by arrow 192. Because the mounting surface of the flange 107 extends parallel to the rotation axis Ax, i.e., horizontally, the casing body 120 can be moved rearward. The direction of movement of the casing body 120 is not limited to the rearward direction; it may also be moved horizontally to the right or left. This movement separates the centrifugal pump 101, from which the suction portion 110 has been removed, from the piping 50 and the connecting pipe 80. One advantage of this embodiment is that the interior is exposed through the opening 121 by removing the suction portion 110 from the main body of the casing 102. As a result, the degree of wear on the impeller 30, particularly the wear on the mouth portion 36 (see FIG. 3A ) on the impeller 30 side, can be easily confirmed through the opening 121. Furthermore, because the mouth portion of suction portion 110 (inner diameter surface 119 shown in FIG. 3A) can also be directly checked, it is easy to check for wear or damage to the mouth portion (36, 119) and other parts over many years of use, greatly improving maintainability. Also, if the degree of wear on inner diameter surface 119 on the suction portion 110 side is significant or if it is damaged due to contact with foreign matter, etc., it is often sufficient to replace suction portion 110 or impeller 30, which increases the reusability of the centrifugal pump and is preferable from the perspective of resource conservation.

[0047] The casing body 120 and the suction section 110 are generally made of the same metal material. Meanwhile, the suction section 110 and the connecting pipe 80 may not be repairable without removing the piping 50, 55, or may be impossible to remove, so they may be made of different materials instead of the same metal material. For example, they may be made of stainless steel or titanium alloy, which have high strength and rust resistance. In addition to the structure of this embodiment, a companion flange 150 shown in FIG. 6 may be interposed between the connecting pipe 80 and the flange 107. The companion flange 150 has a flow passage 151 with the same inner diameter as the flange 107 and is used as a spacer. Four through holes 152 are formed in the circumferential direction to allow bolts (not shown) to pass through. In the configuration of this modified example, when the casing body 120 is pulled out rearward, the companion flange 150 above the flange 107 is removed first, which creates a space above the centrifugal pump 101 that is equal to the thickness of the companion flange 150, making it easier to separate the casing body 120 from the suction part 110. To ensure waterproofing, it is preferable to interpose sealants 170 (see FIG. 2) between both sides of the companion flange 150 and the flanges 83 and 107. [Example]

[0048] Next, the configuration of a centrifugal pump 201 according to the second embodiment will be described with reference to FIGS. 7 and 8. FIG. 7 is a perspective view of the centrifugal pump 201 as an example of fluid equipment according to the second embodiment. The centrifugal pump 201 according to the second embodiment differs from the centrifugal pump 101 according to the first embodiment in the shapes of the suction section 210 and the casing main body 220 and the connection structure therebetween. The casing of the centrifugal pump 201 is formed by three components: the casing main body 220, the suction section 210, and the rear cover 40. The suction section 210 is fixed to the casing main body 220 by nuts 228 at four positions in the circumferential direction. The casing main body 220 has flanges 207 at four positions in the circumferential direction, through which bolts are passed. The flanges 207 have through holes formed therein, and are manufactured integrally with the casing main body 220 so as to protrude radially outward from the outer circumferential surface of the casing main body 220. The suction portion 210 and the casing main body portion 220 are fixed together by four stud bolts 227 and nuts 228 and 229 that are screwed onto the stud bolts.

[0049] The shape of the first flange 216 formed around the suction port 215 is similar to the flange 116 of the first embodiment in terms of outer diameter and thickness, but differs in that the screw holes 217 of the flange 216 are formed as blind female screw holes 217. However, the female screw holes 217 may be formed as through holes as in FIG. 3. In addition, the suction portion 210 is provided with four reinforcing ribs 218 extending parallel to the rotation axis Ax. The ribs 218 extend to the vicinity of the through holes for the stud bolts 227. The first flange 216, the front wall surface 211, and the ribs 218 are manufactured by integral metal molding. The shape of the conduit portion 214 and the fact that an inner diameter portion 219 is formed on one side of the ribbon portion are similar to those of the suction portion 110 shown in FIG. 3.

[0050] FIG. 8 shows a cross section (cut surface) of the centrifugal pump 201 taken along a vertical cross section passing through the rotation axis Ax, viewed from the left side. The casing of the centrifugal pump 201 is formed by a casing main body 220, an inlet 210, and a rear cover 40. A protrusion 222 is formed on one side of a mating portion of an opening 221 on the front side of the casing main body 220, and a recess 212 is provided on the inlet 210 side. The protrusion 222 is shaped to be convex-convexly coupled to the recess 212 and is formed around the entire circumference in the direction of rotation. The recess 212 is also formed around the entire circumference in the direction of rotation. The inner wall surface (inner diameter portion) of the protrusion 222 forms the opening 221 formed in the casing main body 220. A seal material 209 is interposed in the recess 212. A flange 213 is formed to extend radially outward from the same plane as the bottom surface (front surface) of the recess 212. The thickness of each of recess 212 and protrusion 222 may be formed to be approximately the same as the thickness of suction portion 210 and casing main body 220. Sealing material 209 may be any material as long as it can be inserted into the recessed portion of recess 212, but it is preferable that it be a circumferentially continuous sheet-like material with a thickness of about 3 mm that corresponds to the recess shape of recess 212. Furthermore, sealing material 209 may be formed from rubber such as chloroprene rubber that is generally used for water sealing, but other water sealing members or materials may also be used.

[0051] Through holes are formed in flange 213 to fasten suction portion 210 and casing main body 220 together with bolts. Flange 213 extends radially outward in four directions from uneven portion 204, which is circled in black. Meanwhile, flange 207, with through holes formed therein, is formed on the outer periphery of casing main body 220. Opposing surfaces 213b and 207b are formed on the rear side of flange 213 and flange 207, respectively. Opposing surface 207b of flange 207 and opposing surface 213b of suction portion 210 are not in contact with each other and are located on an extension of the outer periphery of uneven portion 204 in the radial direction. Opposing surface 207b is located on the outer periphery extending radially outward from the outermost edge of the circle of casing main body 220. Through holes are formed in flanges 213 and 207 to pass stud bolts 227 through.

[0052] Suction portion 210 and casing main body 220 are connected by passing stud bolts 227 through bolt holes in flanges 213 and 207, and tightening nuts 228 and 229 from both the suction portion 210 side and the casing main body 220 side. Tightening nuts 228 and 229 applies pressure to sealing material 209, such as rubber packing, inserted into uneven portion 204, and tightly seals suction portion 210, sealing material 209, and casing main body 220 together without any gaps, thereby reliably preventing water leakage from uneven portion 204.

[0053] One of the features of the method of fixing the suction unit 210 in the second embodiment is that when separating the casing main body 220 and the suction unit 210 as shown in FIGS. 5 and 6, it is sufficient to remove the nut 229 on the rear side of the casing main body 220. Because the nut 229 is on the side that is moved (the drive unit side in FIG. 6), it is easy to handle a work tool, improving the workability of removal. Note that, as a modification of the second embodiment, the thickness of the flange 213 of the suction unit 210 may be increased to form a female threaded hole that screws into a bolt, and the casing main body 220 and the suction unit 210 may be fixed from the rear side with a bolt instead of the stud bolt 227 and nut 229. With this configuration, the casing main body 220 and the suction unit 210 can be separated simply by loosening the bolt from the removal side (rear side). [Example]

[0054] Next, the configuration of a centrifugal pump 201A according to the third embodiment will be described with reference to FIG. 9. FIG. 9 is a vertical cross-sectional view of the centrifugal pump 201A taken along a line passing through the rotation axis Ax. The basic structure of the centrifugal pump 201A is the same as that of the centrifugal pump 201 according to the second embodiment. That is, a suction section 210 is attached to a main body portion of the casing (casing main body 120) from the front side (the side opposite the drive device 90), and a rear cover 40A is attached to the rear side (the side opposite the drive device 90). The suction section 210 is the same component as the suction section 210 shown in FIGS. 7 and 8. Meanwhile, the shape of the rear cover 40A is the same as that of the rear cover 40 shown in FIG. 3A, in which the cylindrical wall 42 that closes the inside of the opening 125 has a flange 43A that is an enlarged protruding portion extending radially outward from the rear end of the cylindrical wall 42. Flanges 213, 207, and 43A each have a through hole formed at the same position parallel to rotation axis Ax, through which stud bolt 227A passes. Nuts 228 and 229 are fastened near the front and rear ends of stud bolt 227A to fasten casing main body 120, suction section 210, and rear cover 40A together. That is, by passing stud bolt 227A through the corresponding through hole and fastening it with nuts from the suction section 210 side and the rear cover 40A side, suction section 210, casing main body 220, and rear cover 40A can be connected together. Example 3 enables a reduction in the number of work steps compared to when the connection work between suction section 210 and casing main body 120 and the connection work between casing main body 120 and rear cover 40A are performed separately. [Example]

[0055] Next, with reference to FIG. 10, the configuration of a centrifugal pump 301 according to the fourth embodiment will be described. FIG. 10 is a vertical cross-sectional view of the centrifugal pump 301, taken along the axis of rotation Ax. In the fourth embodiment, the shape of the casing body 320 in front of the impeller 30 and the shape of the upper portion near the discharge port 106 are the same as those of the centrifugal pump 101 shown in FIGS. 1 to 3A. The casing body 120 of the first embodiment differs from the casing body 320 of the fourth embodiment in that the casing body 320 does not have a rear opening 125 (see FIG. 3A). In other words, the casing body 320 of the fourth embodiment has a shape in which the casing body 120 and the rear cover 40 shown in FIG. 3A are integrally manufactured. The detachable suction section 110 used in the centrifugal pump 301 is the same part as that in the centrifugal pump 101 of the first embodiment. The shape of the internal space formed in the casing body 320, that is, the centrifugal spaces 21 and 22 and the flow passages 23 and 24 connecting the centrifugal spaces 21 to 22 to the discharge port 106, are the same as those of the centrifugal pump 101 of the first embodiment.

[0056] A bent portion 322 is provided on the rear side of the casing main body 320. The bent portion 322 is a portion whose cross-sectional shape is bent into a hairpin shape so that the wall surface protrudes rearward, and is formed in this manner in order to configure the same internal shape as the casing main body 120 shown in FIGS. 1 to 3A. A rear wall surface 325 is formed on the rear side of the casing main body 320, and a bearing portion 60 is connected to a rib 326 extending from the rear wall surface 325. The shape of the rotating shaft 7 journaled by the bearing portion 60 and the configuration of the bearings and the like are the same as those of the centrifugal pump 101 of the first embodiment.

[0057] In the fourth embodiment, a structure without an opening such as the opening 125 shown in FIG. 3A at the rear of the casing main body 320 is possible because the suction section 110 is configured to be detachable from the casing main body 320 and the size of the front opening 321 is configured to be slightly larger than the diameter of the impeller 30. During manufacturing and assembly, the impeller 30 can be placed inside the casing main body 320 from the front side through the opening 321 and bolted to the rotating shaft 7. During bolt tightening, the flange 116 is positioned on the inner periphery closer to the rotation axis Ax than the projection range 118 required for tightening the bolt 129. As a result, the flange 116 is prevented from interfering with tools when tightening or loosening the bolt 129, resulting in excellent workability during installation and removal. Furthermore, the impeller 30 can be replaced from the suction section 110 side of the casing main body 320. As a result, the number of parts in the centrifugal pump 301 is reduced, and the number of steps in product management and assembly work can be reduced. Furthermore, the portion of the casing main body 320 rearward of the opening 321 in the direction of the rotation axis Ax can be molded from a single metal material, thereby realizing a centrifugal pump 301 with high rigidity and excellent durability. Note that the configuration in which the opening 321 is provided only on the front side of the casing main body 320 shown in this embodiment 4 can also be applied to the centrifugal pump 201 of embodiment 2. [Example]

[0058] Next, referring to Fig. 11, a connection configuration between a connecting pipe 80A according to the fifth embodiment and a discharge portion of a casing main body 120 of a centrifugal pump 101 will be described. Fig. 11 is a perspective view of the connecting pipe 80A and flange 107 of the fifth embodiment, viewed obliquely from above. The suction portion 110 (see Fig. 2) is in a state where it has been removed from the casing main body 120. The fifth embodiment relates to improvements in the shape of the connecting pipe 80A and the method of connecting the connecting pipe 80A to the flange 107 of the casing main body 120, and other parts not mentioned are configured the same as the centrifugal pump 101 of the first embodiment.

[0059] The basic function of the connecting pipe 80A is the same as that of the connecting pipe 80 of the first and second embodiments, but differs in that the central axis of the pipe section 88c of the bent connecting pipe 80A is arranged to form an angle greater than 0° and less than 180° with respect to the central axis of the discharge port 106 (see FIG. 3) and the pipe section 88a. Furthermore, the connecting pipe 80 differs from the connecting pipe 80 in that the surface of the connecting pipe 80 facing the flange 107 (flange 83A) is formed with oval holes 89a-89d instead of circular through-holes. By forming the through-holes for bolts of the flange 83A as oval holes 89a-89d in this way, it is possible to finely adjust the bending direction within a predetermined range. The bent pipe 88 (88a-88c) is formed by connecting two pipe sections 88a and 88c with a connecting section 88b. The pipe sections 88a and 88c are connected to the connecting section 88b by welding. It should be noted that instead of manufacturing the bending pipe 88 in a bent shape, the bending pipes 88a to 88c may be formed as a single, gently bent pipe.

[0060] Instead of providing the oblong holes 89a-89d in the flange 86 of the connecting pipe 80A, the oblong holes 89a-89d may be formed in the shape of the through-hole 108 in the flange 107 on the casing main body 120 side. Also, the through-holes on both sides of the flange 86 and the flange 107 may be formed as oblong holes. Ideally, the shape of the bent pipe 88 of the bent connecting pipe 80A is manufactured each time to match the position and orientation of the piping 55 connected downstream. However, it is more convenient to prepare several types of connecting pipes 80A having bent pipes 88 with predetermined angles, such as 30°, 60°, and 90°, and then select and use the most suitable angle from among them. By using the connecting pipe 80A of Example 5, the surface of the flange 86 can be freely rotated in the circumferential direction within the range in which the oblong holes 89a-89d and the through-hole 108 correspond to each other. Furthermore, by fixing the connecting pipe 80A to the centrifugal pump 101 at any position, it is possible to change the discharge direction from the connecting pipe 80A to any direction that matches the attached piping 55 (see FIG. 5 for the reference numerals). Even if the central axis direction of the opening 85 of the connecting pipe 80A is changed, the flange 107 on the centrifugal pump 101 side and the flange 83A of the connecting pipe 80A remain in contact on a horizontal plane, so it is possible to perform the removal work of the centrifugal pump 101 shown in FIGS. 4 to 6 in the same way.

[0061] While the present invention has been described above based on the embodiments, it is not limited to the above-described embodiments and various modifications are possible within the spirit and scope of the present invention. For example, in Example 1, the size of the front opening 125 of the casing body 120 can be larger than the outer diameter of the mouth portion (the outer position of the inner diameter surface 119) and smaller than the diameter of the impeller 30. Even if the front opening 121 is small, the impeller 30 can be installed into the casing body 120 through the rear opening 125, so this does not pose a problem in manufacturing and assembly. Even in this modification, the portion corresponding to the second flange 107 of the suction portion 110 is located radially outward of the mouth portion, so the condition of the mouth portion (inner diameter surface 119) can be directly confirmed when the suction portion 110 is removed from the casing body 120. Note that when this modification is adopted, it is important to make the front wall surface 111 sufficiently thick to form a screw hole 124 (see FIG. 3B) in the casing body 120. [Explanation of symbols]

[0062] 1 centrifugal pump 2 casing 4 legs 5 suction port 6 Outlet 7 Rotating shaft 8 Coupling 9 Bolt 10 cylindrical portion 11 front wall surface 16, 18 flange 17, 19: through holes; 21, 22: centrifugal spaces; 23, 24: flow passages 25 opening 26 sealing material 30 impeller 31 front wall 32 Inlet 33 Blade 34 Rear wall 35 Outlet 36: Mouth section 40, 40A: Rear cover 41: Rear wall 41a Mounting surface 42 Cylindrical wall 43, 43A Flange 45 Through hole 46 Bolt 50 (Suction side) piping 51 Flange portion 55 (Discharge side) piping 56 Flange portion 60 bearing portion 61 bearing case 71 bolt 72 Nut 80, 80A Connecting pipe 81 Straight pipe 82, 85 Opening 83, 86 Flange 84, 87 Through hole 88a, 88c Pipe section 88b Connection section 89a~89d Oblong holes 90 Drive unit 91 Output shaft 92 Coupling 95 Base 101 centrifugal pump 102 casing 106 discharge port 107 (third) flange 108 through hole 109 sealing material 110 suction portion 111 front wall surface 112 cylindrical wall 112a opposing surface 113 flange 113a through hole 113b mounting surface 114 pipe section 115 suction port 116 (first) flange 117 through hole 119 Inner diameter surface 120 Casing body 121 Opening 121a Cylindrical surface 122 Opposing surface 123 Mounting surface 124 Screw hole 125 opening 126 contact surface 126a screw hole 127 through hole 129 Bolt 150 Companion flange 151 Flow path 152 through hole 170 sealing material 190 spacer 201, 201A Centrifugal pump 204 Concave and convex part 207 Flange 207b opposing surface 209 sealing material 210 suction portion 211 front wall surface 212 recess 213 flange 213b opposing surface 214 pipe section 215 suction port 218 rib 220 casing body 221 opening 222 protrusion 227, 227A Stud bolts 228, 229 Nuts 301 centrifugal pump 320 casing body 321 opening 322 Bend 325 Rear wall 326 Rib Ax rotation axis

Claims

1. an impeller fixed to a rotating shaft rotated by a driving device and adapted to suck in and discharge a fluid; a casing that houses the impeller and has a suction port that draws in a fluid in the axial direction and a discharge port that discharges the fluid that has been pressurized by the impeller; the casing has a flow path that guides the liquid discharged from the impeller to the discharge port while rotating the liquid in a circumferential direction, and a mouth portion is formed between the impeller and the casing so as to face each other with the minimum gap therebetween, a suction section extending from the suction port to the mouth section of the casing is configured to be detachable from the main body section of the casing; A fluid device characterized in that the size of a circular opening formed in the main body and into which the suction part is attached is larger than the diameter of the impeller.

2. The suction portion is a first flange for connecting the suction port to an external pipe; a wall surface that closes the opening and is located on the suction side of the impeller; a second flange provided on the outer circumferential side of the wall surface and having a through hole formed therein for fixing to the main body; a conduit connecting the first flange and the wall surface; The main body portion has a mounting surface that contacts the second flange, 2. The fluid device according to claim 1, wherein the second flange is fixed to the mounting surface of the main body by a plurality of screw means.

3. The fluid device according to claim 2, characterized in that the mouth portion is composed of an inner diameter surface formed inside the wall surface and an outer diameter surface formed outside the suction port of the impeller and facing the inner diameter surface in a non-contact state.

4. a through hole is formed in the second flange, a mounting surface having a screw hole formed therein is formed on the radially outer side of the mounting surface of the main body; The fluid device according to claim 3, wherein the suction portion is threadedly engaged with the screw hole by a plurality of bolts that are oriented parallel to the axial direction of the rotary shaft and pass through the through hole.

5. the second flange has a cylindrical surface and a plurality of protrusions partially protruding radially outward from the cylindrical surface, and through holes are formed in the protrusions; The main body portion has a main body side flange formed thereon, the main body flange protruding radially outward from an outer circumferential surface thereof and having a second through hole formed therein; The fluid device described in claim 3, characterized in that the suction portion is fixed to the main body portion by a bolt and nut whose center axis is oriented parallel to the rotation axis, via the through hole of the protrusion portion and the second through hole of the main body side flange.

6. the casing includes a rear cover that enables a rear wall surface located on the drive device side to be separated from the main body portion, The rear cover is fixed to the main body by bolting. the rear cover is provided with a through-hole through which the rotary shaft passes from the drive device side, and a bearing portion that rotatably holds the rotary shaft, The fluid device according to claim 5, wherein the rear end of the rotary shaft, which penetrates the rear cover and extends to the outside, is connected to an output shaft of the drive unit via a coupling.

7. The rear cover is formed with a rear flange that protrudes radially outward and has a through hole formed therein, The fluid device described in claim 6, characterized in that the suction portion and the rear cover are fixed to the main body portion by a bolt and a nut that pass through the protrusion portion, the main body side flange, and the rear side flange and have a center axis oriented parallel to the rotation axis.

8. a joint portion of the suction portion and the main body portion is cylindrical and coaxial with the rotation shaft, and is formed with a fitting structure of a recess and a protrusion, the opening of the main body casing is formed by the protrusion formed on the main body side, The recess is formed in the suction portion, 4. The fluid device according to claim 3, wherein an annular seal is interposed between the cylindrical surface of the convex portion and the groove of the concave portion.

9. The fluid device according to any one of claims 2 to 8; a connecting pipe connected between the discharge port of the fluid device and a flange of a pipe to a liquid supply destination; A centrifugal pump system having a drive device that rotates the fluid device, A companion flange is provided between the discharge port and the connecting pipe, A centrifugal pump system characterized in that the rotating shaft of the fluid device and the output shaft of the drive unit are connected by a coupling via a removable spacer.

10. 10. The centrifugal pump system according to claim 9, wherein when the main body and the second flange are separated, the discharge port is disconnected from the connecting pipe, and the spacer is removed, the main body excluding the suction port can be moved parallel to the rotation axis direction toward the drive device.

11. an impeller fixed to a rotating shaft rotated by a driving device and adapted to suck in and discharge a fluid; a casing that houses the impeller and has a suction port that draws in a fluid in the axial direction and a discharge port that discharges the fluid that has been pressurized by the impeller; the casing has a flow path that guides the liquid discharged from the impeller to the discharge port while rotating the liquid in a circumferential direction, and a mouth portion is formed between the impeller and the casing so as to face each other with the minimum gap therebetween, a suction section extending from the suction port to the mouth section of the casing is configured to be detachable from the main body section of the casing; The rear wall surface on the drive device side is configured to be detachable from the main body by a rear cover, A fluid device characterized in that the size of a circular opening formed in the main body portion and into which the suction portion is attached is larger than the outer diameter of the mouth portion, and the size of a circular rear opening into which the rear cover is attached is larger than the outer diameter of the impeller.

12. The suction portion is a first flange for connecting the suction port to an external pipe; a wall surface that closes the opening; a second flange provided on the outer circumferential side of the wall surface and having a through hole formed therein for fixing to the main body; a conduit connecting the first flange and the wall surface; an attachment surface having a screw hole and in contact with the second flange is formed on the outside of the opening of the main body; The fluid device according to claim 11, wherein the second flange is fixed to the main body by a plurality of screw means.

13. The outer diameter of the impeller is larger than the diameter of the mouth portion, 13. The fluid device according to claim 12, wherein the size of the opening to which the suction portion is attached is larger than the outer diameter of the impeller.

14. the first flange is bolted and the second flange is bolted; A fluid device as described in claim 13, characterized in that by removing the bolts of the second flange while keeping the first flange fixed, the fluid device excluding the suction portion can be separated in the direction opposite to the suction portion in the direction of the rotation axis.

15. A fluid device as described in claim 14, characterized in that a third flange for connecting to an external piping is formed radially outside the discharge port, and the mounting surface of the third flange is formed so as to face in a direction parallel to the rotation axis.

Images