centrifugal pump

Abstract

To provide a centrifugal pump which can reduce a dimension in a predefined direction of a case.SOLUTION: A centrifugal pump 1 includes: a cylindrical case 10 extending in an axial direction L; and an impeller 70 stored in the case 10. The case 10 is provided with an intake opening 34 that opens in an orthogonal direction X, and an intake joint 80 is connected to the intake opening 34. The intake joint 80 includes a cylindrical body 81 and a cylindrical flat part 83 that is flat in a predefined direction in which the intake joint is inserted into the intake opening 34.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a centrifugal pump. [Background technology]

[0002] Conventionally, there has been provided a centrifugal pump including a cylindrical case, an impeller housed in the case, and a suction joint and a discharge joint communicating with the case (see, for example, Patent Document 1). In the centrifugal pump described in Patent Document 1, the suction-side joint member (suction joint) is formed in a cylindrical shape with a constant diameter extending in a direction perpendicular to the axial direction of the case, and is connected to the case in the direction perpendicular to the case. Fluid introduced into the case through the suction-side joint member is sent to the discharge-side joint member (discharge joint) by the rotational force of the impeller, and is discharged out of the case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5686827 Summary of the Invention [Problem to be solved by the invention]

[0004] In the centrifugal pump described above, it is sometimes desirable to reduce the dimensions of the case in a predetermined direction due to installation space constraints. However, in the case of the centrifugal pump described above, it is necessary to secure a space at the mounting portion of the suction side coupling member that is equal to or larger than the diameter of the suction side coupling member as a space for mounting the suction side coupling member, which makes it difficult to reduce the dimensions of the case in the predetermined direction.

[0005] An object of the present invention is to provide a centrifugal pump in which the dimensions of the case in a predetermined direction can be reduced. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the object, the centrifugal pump of the present invention is a centrifugal pump comprising a cylindrical case extending in an axial direction and an impeller housed in the case, wherein the case is provided with a suction opening that opens in a direction perpendicular to the axial direction, and a suction joint that communicates with the inside and outside of the case is connected to the suction opening, and the suction joint comprises a cylindrical main body portion and a cylindrical flat portion that is flat in a predetermined direction and is inserted into the suction opening. The axial direction is the height direction, the main body portion and the flat portion have the same central axis, one side and the other side of a cross section cut in the height direction have a shape that is plane-symmetrical with respect to the central axis, the upper end of the main body portion is located at the same position as or below the upper end of the case in the height direction, and the upper end of the flat portion is located between the upper end of the main body portion and the central axis. It is characterized by:

[0007] According to the present invention, by providing a flat portion in the suction fitting, the dimension in a predetermined direction of the connection portion between the suction fitting and the case can be reduced compared to when a cylindrical suction fitting with a fixed diameter is used. Specifically, for example, a flat portion formed by crushing one end of the main body of the suction fitting in a predetermined direction reduces the dimension of the suction fitting side in the predetermined direction, and accordingly reduces the dimension in the predetermined direction of the periphery of the connected suction opening, i.e., the case side. Furthermore, by reducing the dimension in the predetermined direction of the connection portion between the suction fitting and the case, the dimension in the predetermined direction of the case can be reduced accordingly. Therefore, a centrifugal pump can be provided in which the dimension in the predetermined direction of the case can be reduced.

[0008] In a centrifugal pump, the axial direction is the height direction, and this height direction may correspond to the direction of the impeller's rotation axis, which affects the dimensions of the case, resulting in a large case height. For this reason, it is preferable that the flat portion of the suction joint has a flat, cylindrical shape whose height is smaller than its width. In this case, the height of the connection between the suction joint and the case can be reduced, thereby reducing the case height. However, the impeller's rotation axis may be positioned in a specific direction, not just the height direction, such as horizontally or at an angle. In such cases, forming the flat portion in a flat, cylindrical shape in the specific direction can reduce the case size in that direction.

[0009] In addition, For centrifugal pumps, it is sometimes desirable to reduce the height of the case due to installation space limitations. the above According to this configuration, for example, the flat portion can be easily formed by deforming one end of the main body, which has a constant diameter, by uniformly crushing it in a height direction, as an example of a predetermined direction. Furthermore, since the upper end of the flat portion is located between the upper end of the main body and the central axis, a space in the height direction is created between the upper end of the flat portion and the upper end of the main body. This space can be used, for example, when connecting the case and the flat portion by welding, brazing, or the like. Therefore, there is no need to provide a connection allowance for welding, brazing, or the like above the upper end of the main body (i.e., the upper end of the intake joint) on the case side, and the upper end of the case can be set at a lower position accordingly. Furthermore, according to the above configuration, the upper end of the case can be lowered to a position at most equal to the upper end of the main body. This allows the height dimension of the case to be reduced.

[0010] Furthermore, it is preferable that the height dimension L1 of the inner diameter of the flat portion is smaller than the inner diameter D1 of the main body portion, and the width dimension L2 of the inner diameter of the flat portion, which is the dimension of the inner diameter of the flat portion in a direction intersecting the height direction, is larger than the inner diameter D1. In a centrifugal pump, it is possible to reduce the overall diameter of the suction fitting, which has a constant diameter, and simultaneously reduce the dimension of the connected case in a predetermined direction. However, in this case, the flow rate of the fluid introduced into the case may be significantly reduced, degrading the performance of the centrifugal pump. However, according to the configuration of the present invention, by making the height dimension L1 of the inner diameter of the flat portion smaller than the inner diameter D1 of the main body portion and making the width dimension L2 of the inner diameter of the flat portion larger than the inner diameter D1, it is possible to maintain the volume of the flat portion at a predetermined size and prevent a significant reduction in the flow rate of the fluid introduced into the case.

[0011] Furthermore, the case is provided with a top wall portion extending in the orthogonal direction, a bulging portion bulging outward in the height direction from the top wall portion and having a predetermined width, and a blade case at least a portion of which faces the bulging portion in the height direction within the case, and an inlet which serves as a flow path for the fluid flowing in from the suction opening is formed between the bulging portion and the blade case, and a width dimension W of the inlet is preferably the same as or larger than the width dimension L2 of the inner diameter of the flat portion. With this configuration, the fluid introduced into the case through the flat portion flows through a wide inlet having a width dimension W that is the same as or larger than the width dimension L2 of the inner diameter of the flat portion, making it easier to ensure the flow rate of the fluid introduced into the case.

[0012] Furthermore, the impeller case preferably divides the interior of the case into the inlet and an accommodation space that accommodates the impeller, and the impeller case is provided with a communication hole that connects the inlet and the accommodation space, and the inner diameter D2 of the communication hole is preferably the same as or larger than the width dimension L2 of the inner diameter of the flat portion. According to this configuration, fluid introduced into the case from the suction opening flows through the inlet, which is the same as or wider than the width dimension L2 of the inner diameter of the flat portion, and then flows through the communication hole into the accommodation space. At this time, because the inner diameter D2 of the communication hole is set to be the same as or larger than the width dimension L2 of the inner diameter of the flat portion, the fluid can flow from the inlet to the accommodation space while ensuring a sufficient flow rate.

[0013] Furthermore, the suction fitting is preferably provided with a connecting portion connecting the main body portion and the flat portion, and the inner wall of the connecting portion has a tapered shape such that the one side portion and the other side portion in the predetermined direction gradually approach each other as they extend from the main body portion to the flat portion. With this configuration, the provision of a connecting portion in which the one side portion and the other side portion in the predetermined direction of the inner wall are tapered allows the flow rate of fluid flowing from the main body portion to the flat portion to be gradually changed. This reduces pressure loss due to a sudden change in the flow rate of fluid flowing through the suction fitting, and stabilizes the operation of the centrifugal pump. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a centrifugal pump in which the size of the case in a predetermined direction can be reduced. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view of a centrifugal pump according to an embodiment of the present invention; [Figure 2] Cross-sectional view taken along line AA in Figure 1. [Figure 3] Side view of a centrifugal pump. [Figure 4] Top view of a centrifugal pump. [Figure 5] BB line cross-sectional view of FIG. 1. [Figure 6] 3 is a cross-sectional view taken along line CC in FIG. 2. [Figure 7] 1A is a perspective view of the intake joint, and FIG. 1B is a front view of the flat portion of the intake joint as viewed from an orthogonal direction. [Figure 8] 8(A) is a diagram showing an example of a flat portion, and FIG. 8(B) is a diagram showing an example of a flat portion different from the example shown in FIG. 8(A). DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 8. In the following description, the direction along the axis L of the case 10 (described later) is referred to as the height direction, and is referred to as the "height direction Z." One side of the height direction Z is referred to as the "upper side Z1," and the other side is referred to as the "lower side Z2." The direction perpendicular to the height direction Z is referred to as the "orthogonal direction X." The orthogonal direction X is also the radial direction of the case 10. The direction intersecting the longitudinal direction of the suction joint 80 and the second introduction flow path 52 (inlet), described later, is referred to as the "width direction Y." These definitions are provided solely for the sake of convenience and do not necessarily correspond to the directions in the actual use state of the centrifugal pump 1, nor do they limit the directions of the centrifugal pump 1. As shown in FIG. 1, the centrifugal pump 1 includes a case 10, a suction joint 80 and a discharge joint 90 connected to the case 10, and an impeller 70 housed in the case 10. The centrifugal pump 1 is used, for example, in devices that circulate fluids such as refrigerants, and sends the fluid introduced into the case 10 from the suction joint 80 to the discharge joint 90 using the impeller 70, and discharges it outside the case 10.

[0017] The case 10 is made of a metal material such as stainless steel (SUS) and has a generally cylindrical shape extending in the direction of the axis L. As shown in FIG. 2, the case 10 includes a rotor case 20 constituting a lower Z2 portion, a main body case 30 constituting an upper Z1 portion, and a blade case 40 disposed between the rotor case 20 and the main body case 30. The rotor case 20 includes a cylindrical first housing portion 21 extending in the height direction Z. A magnet rotor 74 (described later) is housed in the first housing portion 21. A cylindrical second housing portion 22 protruding toward the lower Z2 is formed at the center of the lower end of the first housing portion 21. The second housing portion 22 has a smaller diameter than the first housing portion 21 and houses a bushing 71 (described later) inside. A flange portion 23 protruding radially outward is formed at the upper end of the first housing portion 21 around the entire circumference. A bracket 24 protruding radially outward from the side wall portion of the first housing portion 21 is provided below the flange portion 23 (Z2). The bracket 24 connects the case 10 to the coil unit 100 by engaging with a fixing protrusion 3a of the coil unit 100, which will be described later.

[0018] The main body case 30 includes a top wall portion 31 that is circular in top view and extends in the orthogonal direction X to form the upper end surface of the case 10, and a cylindrical side wall portion 32 that extends from the outer peripheral edge of the top wall portion 31 to the lower side Z2. The top wall portion 31 is formed with a bulge portion 33 that bulges outward in the height direction Z. As shown in FIGS. 3 and 4 , the bulge portion 33 has a predetermined width in the width direction Y and extends from the center of the top wall portion 31 toward one side in the orthogonal direction X to the outer peripheral edge of the top wall portion 31. An upper end surface 33a of the bulge portion 33 is located at the uppermost end of the case 10 and forms the upper end surface of the case 10. The bulge portion 33 forms a second introduction flow path 52 (inlet) between the upper surface of an upper wall portion 41 of a blade case 40 (described later) and the inner surface of the bulge portion 33. An intake opening 34 and an exhaust opening 35, which open in the orthogonal direction X, are formed through the side wall portion 32. As shown in Fig. 1, in this embodiment, the intake opening 34 and the exhaust opening 35 are formed at positions offset by 90° in the circumferential direction around the axis L when viewed from the direction of the axis L, but this angle can be changed as appropriate. An intake fitting 80 is inserted and fixed into the intake opening 34. A discharge fitting 90 is inserted and fixed into the discharge opening 35.

[0019] The blade case 40 includes an upper wall portion 41 extending in the orthogonal direction X along the top wall portion 31 of the main body case 30, and a cylindrical peripheral wall portion 42 extending downward Z2 from the outer peripheral edge of the upper wall portion 41 and facing the side wall portion 32 of the main body case 30. The upper surface of the upper wall portion 41 faces the inner surface of the top wall portion 31 or the bulging portion 33 in the height direction Z. The lower end portion of the peripheral wall portion 42 is sandwiched between the lower end portion of the side wall portion 32 of the main body case 30 and the outer peripheral end portion of the flange portion 23 of the rotor case 20, and is fixed to these in a sealed state by welding, brazing, or fusion bonding, etc. With this configuration, as shown in FIG. 2, the space inside the case 10 is divided into an introduction flow path 50 between the main body case 30 and the blade case 40, and an accommodation space 60 between the blade case 40 and the rotor case 20. The introduction flow path 50 is a flow path for the fluid introduced (flowed into) the case 10 from the suction opening 34, and includes a first introduction flow path 51 and a second introduction flow path 52, as shown in FIG.

[0020] The first inlet flow path 51 is formed by the space between the side wall portion 32 of the main body case 30 and the peripheral wall portion 42 of the blade case 40, surrounds the accommodation space 60 in the circumferential direction, and forms a reservoir where fluid introduced into the case 10 from the suction opening 34 accumulates. The second inlet flow path 52 is formed by the space between the bulge portion 33 of the main body case 30 and the upper wall portion 41 of the blade case 40. The second inlet flow path 52 is an inlet in the present invention, and as shown in FIG. 5 , its dimension in the height direction Z is determined by the distance between the upper surface of the upper wall portion 41 of the blade case 40 and the inner surface of the bulge portion 33, and is defined as a height dimension H. The dimension in the width direction Y of the second inlet flow path 52 is determined by the width dimension of the inner surface of the bulge portion 33, and is defined as a width dimension W. The second inlet flow path 52 is connected to the accommodation space 60 via a communication hole 43 formed in the center of the upper wall portion 41 of the blade case 40 and penetrating in the height direction Z. In this embodiment, the size of the inner diameter of this communication hole 43 is defined as inner diameter D2 (shown only in Fig. 2). As shown in Fig. 1, a control wall 44 that temporarily blocks the fluid sent by the impeller 70 is formed in the vicinity of the discharge opening 35 of the peripheral wall portion 42 of the blade case 40, perpendicular to the flow direction of the fluid. This makes it possible to increase the pressure in the vicinity of the discharge opening 35 by the fluid blocked by the control wall 44, thereby making it possible to increase the discharge pressure and further ensure a sufficient flow rate.

[0021] The impeller 70 is accommodated in the accommodation space 60 within the case 10. The impeller 70 includes a bushing 71 accommodated in the second accommodation portion 22 of the rotor case 20. The bushing 71 is a bearing and is formed in a cylindrical shape extending in the height direction Z. A shaft 72 serving as a rotation axis is inserted into the center of the bushing 71 and is supported rotatably about an axis L. A plurality of blade members 73 are attached to the outer circumferential surface of the shaft 72, protruding radially outward in the radial direction of the shaft 72. A lower portion of the blade members 73 is inserted into the center of a cylindrical magnet rotor 74 and fixed to the magnet rotor 74, thereby enabling the blade members 73 and the shaft 72 to rotate about the axis L in accordance with the rotation of the magnet rotor 74.

[0022] The case 10, formed as described above and housing the impeller 70 therein, is connected to the coil unit 100. As shown in FIG. 2, the coil unit 100 includes a bottom cover 2 and a coil case 3, which combine to form a single box. A fixing protrusion 3a protruding radially inward is formed at the upper end of the coil case 3. The fixing protrusion 3a engages with the bracket 24 of the case 10, thereby connecting the case 10 and the coil unit 100. The bottom cover 2 and the coil case 3 house a control board 4 that controls the rotation of the magnet rotor 74 and a stator coil 5 disposed above the control board 4. The stator coil 5 includes a cylindrical bobbin 5a extending in the orthogonal direction X, a stator core 5b disposed at the center of the bobbin 5a, and a winding 5c ​​wound around the outer periphery of the bobbin 5a. An upper cover 6 is disposed above the stator coil 5. A through-hole 7 for fitting the first housing portion 21 and the second housing portion 22 of the case 10 therein is formed in the center of the coil unit 100 configured in the height direction Z.

[0023] Next, the suction joint 80 will be described. The suction joint 80 is a piping component made of a metal material such as C1220T (phosphorus-deoxidized copper). As shown in FIG. 7(A), the suction joint 80 includes a cylindrical main body 81 extending in the orthogonal direction X, a connecting portion 82 connected to the main body 81, and a flat portion 83 connected to the connecting portion 82. The main body 81 has a constant diameter, and the end opposite the connecting portion 82 is connected to other piping or the like provided in a device other than the centrifugal pump 1. The connecting portion 82 connects the main body 81 and the flat portion 83. The connecting portion 82 gradually decreases in height direction Z and increases in width direction Y toward the flat portion 83. As shown in FIG. 2, an upper side Z1 portion (one side in a predetermined direction) and a lower side Z2 portion (the other side) of the inner wall of the connecting portion 82 have a tapered shape that gradually approaches each other from the main body 81 toward the flat portion 83.

[0024] The flat portion 83 is a portion connected to the suction opening 34, and is formed into a cylindrical shape flat in the height direction Z (a predetermined direction), for example, by deforming the main body portion 81 so as to be crushed in the height direction Z (a predetermined direction). The flat portion 83 is inserted into the suction opening 34 and fixed to the case 10 in a sealed state by welding, brazing, or fusion bonding, and its internal space communicates with the introduction flow path 50 of the case 10. As a result, the suction joint 80 communicates with the inside and outside of the case 10. In this embodiment, the main body portion 81, connecting portion 82, and flat portion 83 formed in this manner have a coaxial central axis C as shown in FIG. 2. In the main body portion 81, connecting portion 82, and flat portion 83, an upper side Z1 (one side in the height direction Z) and a lower side Z2 (the other side) of a cross section cut in the height direction Z have shapes that are plane-symmetrical with respect to the central axis C.

[0025] As shown in FIG. 7(B), the opening shape of the end of the flat portion 83 opposite the main body portion 81 side is an ellipse that is long in the width direction Y. In this embodiment, the "flat" of the flat portion 83 includes any shape whose dimension in the width direction Y is greater than its dimension in the height direction Z. Therefore, the opening shape of the flat portion 83 is not limited to an ellipse that is long in the width direction Y, and can be selected as appropriate. For example, as shown in FIG. 8(A), the opening shape of the flat portion 83 may be an ellipse that is long in the width direction Y, or as shown in FIG. 8(B), it may be a rounded rectangle that is long in the width direction Y. In addition to these, various shapes such as a diamond shape can be selected for the opening shape of the flat portion 83. Furthermore, in this embodiment, the main body 81, the connecting portion 82, and the flat portion 83 are formed so that the upper side Z1 (one side in the height direction Z) and the lower side Z2 (the other side) of a cross section cut in the height direction Z have shapes that are plane-symmetrical about the central axis C. However, this is not limited to this, and the opening shape of the flat portion 83 can also be, for example, a triangular shape that does not have such plane-symmetrical shape. In this way, the shape of the opening of the flat portion 83 can be selected from a variety of shapes as appropriate, and the flat portion 83 can be formed in a shape suitable for the purpose, such as flow rate, strength, or durability.

[0026] Next, the discharge joint 90 will be described. The discharge joint 90 includes a main body 91, a connecting portion 92, and a flat portion 93, which are formed in the same manner as the suction joint 80. The flat portion 93 of the discharge joint 90 is inserted into the discharge opening 35 of the case 10 and fixed to the case 10 in a sealed state by welding, brazing, or fusion bonding, and its internal space communicates with the accommodation space 60 of the case 10. As a result, the discharge joint 90 communicates with the inside and outside of the case 10. In this state, as shown in FIG. 1 , a part of the opening edge of the flat portion 93 abuts against the control wall 44 of the impeller case 40 described above.

[0027] The operation of the centrifugal pump 1 configured as described above will now be described. First, by passing a current through the stator coil 5, the stator coil 5 is excited, causing the magnet rotor 74 to rotate around the axis L together with the shaft 72 and the blade members 73. This causes the fluid in the accommodation space 60 to flow toward the discharge opening 35 and be discharged to the outside of the case 10 through the discharge joint 90. At this time, due to the pressure difference between the accommodation space 60 and the second inlet flow path 52, the fluid flows from the second inlet flow path 52 through the communication hole 43 to the accommodation space 60. Then, the fluid flows from the first inlet flow path 51 to the second inlet flow path 52. The fluid is also drawn into the first inlet flow path 51 from the suction joint 80 (suction opening 34). In this way, a fluid flow path is formed from the suction joint 80 to the inlet flow path 50 (first inlet flow path 51, second inlet flow path 52), the communication hole 43, the accommodation space 60, and the discharge joint 90.

[0028] In the suction joint 80 formed as described above, as shown in FIG. 2, the upper end 81a of the main body portion 81 is located below the upper end surface 33a of the bulge portion 33 (the other upper surface of the case 10) in the height direction Z, at a position Z2. Furthermore, the distance P1 from the central axis C of the suction joint 80 to the upper end 83a of the flat portion 83 is smaller than the distance P2 from the central axis C to the upper end 81a of the main body portion 81. As a result, the upper end 83a of the flat portion 83 is located between the upper end 81a of the main body portion 81 and the central axis C. This creates a space in the height direction Z between the upper end 83a of the flat portion 83 and the upper end 81a of the main body portion 81. This space can be used, for example, when connecting the case 10 and the flat portion 83 by welding, brazing, or the like. Therefore, there is no need to provide a connection allowance for the above-mentioned welding, brazing, etc. on the case 10 side above the upper end 81a of the main body 81 (i.e., the upper end of the suction joint 80) Z1, and therefore the upper end of the case 10 can be set at a lower position.

[0029] In this embodiment, the upper end 81a of the main body 81 is located below the upper end surface 33a of the bulging portion 33 (the upper end surface of the case 10) on the side Z2. However, this is not limited thereto, and the upper end 81a of the main body 81 and the upper end surface 33a of the bulging portion 33 may be located at the same position in the height direction Z. With this configuration, the upper end surface 33a of the bulging portion 33 can be lowered to the same position as the upper end 81a of the main body 81 at most. This reduces the height dimension of the case 10. Specifically, the distance P1 from the central axis C to the upper end 83a of the flat portion 83 is preferably set to approximately half or less (approximately 50% or less) the distance P2 from the central axis C to the upper end 81a of the main body 81, and more preferably set to approximately one-quarter or more (approximately 25% or more) of the distance P2. This more preferred embodiment allows the dimension of the case 10 in the height direction Z to be reduced to the extent that the pressure loss does not become too large while ensuring a sufficient connection allowance for the suction joint 80.

[0030] 2, the central axis C of the suction joint 80 is preferably disposed at a position facing the peripheral wall portion 42 of the impeller case 40 in the orthogonal direction X. In this configuration, the suction opening 34 is formed in a portion of the upper part of the case 10 facing the peripheral wall portion 42 of the impeller case 40, and the flat portion 83 is connected to the suction opening 34. This allows the fluid flowing into the case 10 from the suction opening 34 to collide with the peripheral wall portion 42 of the impeller case 40, thereby increasing the pressure of the fluid at the collision point. This increases the momentum of the fluid near the suction opening 34, improving the suction pressure and making it easier to ensure the flow rate of the centrifugal pump 1. Furthermore, as described above, the configuration in which the central axis C of the suction joint 80 is disposed at a position facing the peripheral wall portion 42 of the impeller case 40 in the orthogonal direction X allows a large space to be secured below the case 10 for arranging the coil unit 100. In this case, it is preferable that the upper end 83a of the flat portion 83 is disposed at the same position as the upper surface of the upper wall portion 41 of the impeller case 40 in the height direction Z, or at a position Z2 below the upper surface of the upper wall portion 41. By doing so, the introduction flow path 50 is ensured, and the bulging portion 33 can be brought closer to the impeller case 40 in the height direction Z without being affected by the flat portion 83, and the height dimension of the centrifugal pump 1 can be further reduced.

[0031] Furthermore, in the flattened portion 83 formed as described above, the dimension of the inner diameter in the height direction Z is set smaller than the inner diameter of the main body portion 81. Furthermore, the dimension of the inner diameter in the width direction Y of the flattened portion 83 is set larger than the inner diameter of the main body portion 81. Specifically, assuming that the main body portion 81 is a 1- to 3-distribution pipe, its inner diameter D1 (see FIGS. 1 and 2) is approximately 2 mm to 10 mm, while the height dimension L1 (see FIG. 2) of the inner diameter of the flattened portion 83 is small, such as approximately 1 mm to 3 mm. Furthermore, while the inner diameter D1 is approximately 2 mm to 10 mm, the width dimension L2 (see FIG. 1) of the inner diameter of the flattened portion 83 is large, such as approximately 3 mm to 15 mm.

[0032] Here, from the viewpoint of reducing the dimension of the centrifugal pump 1 in the height direction Z, it is preferable that the height dimension L1 be small. If the height dimension L1 is small, the height dimension of the outer diameter of the flat portion 83 can also be easily reduced accordingly, which allows the height dimension of the suction opening 34 to which the flat portion 83 is connected to be reduced. Furthermore, the space in the case 10 required for the above-mentioned welding, brazing, and the like can also be reduced. However, if the height dimension L1 is reduced, the volume of the flat portion 83 decreases, which reduces the flow rate of the fluid flowing through the centrifugal pump 1. Therefore, from the viewpoint of reducing the height dimension L1 while maintaining the flow rate, it is preferable that the height dimension L1 be set to a value between approximately 1 / 10 and approximately 1 / 2 times the inner diameter D1 (approximately 10% to approximately 50%), and the width dimension L2 be set to a value between approximately 6 / 5 and approximately 15 / 2 times the inner diameter D1 (approximately 120% to approximately 750%). Furthermore, it is more preferable to set the height dimension L1 to be between 1 / 4 and 1 / 2 times (25% to 50%) the inner diameter D1, and to set the width dimension L2 to be between 3 / 2 and 3 times (150% to 300%) the inner diameter D1. This more preferable embodiment can further reduce pressure loss near the flattened portion 83, thereby further preventing a decrease in the fluid flow rate.

[0033] On the other hand, in terms of reducing the dimension of the centrifugal pump 1 in the height direction Z, it is also possible to reduce the size of the bulging portion 33 of the main body case 30 in the height direction Z, for example. However, just like the flat portion 83, simply reducing the size of the bulging portion 33 in the height direction Z reduces the volume of the second inlet flow path 52, thereby reducing the flow rate of the fluid flowing through the centrifugal pump 1. Therefore, it is preferable to set the width dimension W of the second inlet flow path 52 larger than the height dimension H of the second inlet flow path 52. Specifically, it is preferable to set the height dimension H of the second inlet flow path 52 to about 0.1 mm to 15 mm, and the width dimension W of the second inlet flow path 52 to about 10 mm to 30 mm. It is more preferable to set the width dimension W to about 10 times to about 150 times the height dimension H (about 1000% to about 15000%), and even more preferably to set it to about 15 times to 50 times the height dimension H (1500% to 5000%). This more preferred embodiment makes it possible to further reduce the pressure loss in the vicinity of the second introduction flow path 52, and to further prevent a decrease in the flow rate of the fluid, while reducing the height dimension of the case 10.

[0034] Furthermore, in terms of ensuring the flow rate, the relationship between the width dimension L2 of the inner diameter of the flattened portion 83 and the width dimension W of the second inlet flow path 52 is also important. If the width dimension W is insufficient relative to the width dimension L2, the flow rate of the fluid in the second inlet flow path 52 will be unintentionally throttled. Here, the width dimension W is preferably set to be equal to or larger than the width dimension L2. Specifically, the width dimension W is preferably set to be approximately 1 to 10 / 3 times the width dimension L2 (approximately 100% to 333%), and more preferably set to be 3 / 2 to 3 times the width dimension L2 (approximately 150% to 300%). This more preferable embodiment further reduces pressure loss near the second inlet flow path 52, thereby further preventing a decrease in the flow rate of the fluid.

[0035] Furthermore, in terms of ensuring the flow rate, the relationship between the width dimension L2 of the inner diameter of the flat portion 83 and the inner diameter D2 of the communication hole 43 of the impeller case 40 is also important. If the inner diameter D2 is insufficient relative to the width dimension L2, the flow rate of the fluid through the communication hole 43 will be unintentionally throttled. Here, the inner diameter D2 of the communication hole is preferably the same as or larger than the width dimension L2 of the inner diameter of the flat portion. Specifically, the inner diameter D2 is preferably set to approximately 8 mm to 15 mm. The inner diameter D2 is preferably set to approximately 1 to 5 times the width dimension L2 (approximately 100% to 500% of the width dimension L2), and more preferably to 1.05 to 3 times the width dimension L2 (approximately 105% to 300% of the width dimension L2). This more preferable embodiment further reduces pressure loss near the communication hole 43, thereby preventing a reduction in the flow rate of the fluid and further miniaturizing the centrifugal pump 1.

[0036] As described above, according to the embodiment, by providing suction fitting 80 with flat portion 83, the height dimension in a predetermined direction of the connection portion between suction fitting 80 and case 10 can be reduced compared to when a cylindrical suction fitting with a fixed diameter is used. Specifically, for example, flat portion 83 is formed by, for example, crushing one end of main body 81 of suction fitting 80 in a predetermined direction, thereby reducing the height dimension of suction fitting 80 in the predetermined direction, and accordingly, the dimension in the predetermined direction of the area around suction opening 34, i.e., the case 10, can be reduced. Furthermore, by reducing the dimension in the predetermined direction of the connection portion between suction fitting 80 and case 10, the dimension in the predetermined direction of case 10 can be reduced accordingly. Therefore, a centrifugal pump 1 can be provided in which the dimension in the predetermined direction of case 10 can be reduced.

[0037] In the centrifugal pump 1, as in this embodiment, the direction of the axis L corresponds to the height direction Z. This height direction Z may correspond to the extension direction of the shaft 72 of the impeller 70, which affects the dimensions of the case 10, resulting in an increase in the height of the case 10. For this reason, it is preferable that the flat portion 83 of the suction joint 80 has a flat cylindrical shape whose height is smaller than its width. In this case, the height of the connection portion between the suction joint 80 and the case 10 can be reduced, thereby reducing the height of the case 10. However, the shaft 72, which is the rotation axis of the impeller 70, may be oriented not only in the height direction Z but also in a predetermined horizontal or inclined direction. In this case, forming the flat portion 83 in a flat cylindrical shape in the predetermined direction can reduce the dimension of the case 10 in that direction.

[0038] Furthermore, in this embodiment, the direction of axis L is the height direction Z, and the main body 81 and the flat portion 83 of the suction fitting 80 have a coaxial central axis C. The upper side Z1 and the lower side Z2 of a cross section cut in the height direction Z have a plane-symmetrical shape about the central axis C. In the centrifugal pump 1, it is sometimes desirable to reduce the height dimension of the case 10 due to installation space constraints. According to this configuration, the flat portion 83 can be easily formed, for example, by deforming one end of the main body 81, which has a constant diameter, so that it is uniformly crushed in the height direction Z, as an example of a predetermined direction. Furthermore, the upper end 83a of the flat portion 83 is located between the upper end 81a of the main body 81 and the central axis C, thereby creating a space in the height direction Z between the upper end 83a of the flat portion 83 and the upper end 81a of the main body 81. This space can be used, for example, when connecting the case 10 and the flat portion 83 by welding, brazing, or the like. Therefore, there is no need to provide a connection allowance for welding, brazing, or the like on the case 10 side above the upper end 81a of the main body 81 (i.e., the upper end of the suction joint) Z1, and the upper end of the case 10 can be set at a lower position accordingly. According to the above configuration, the upper end of the case 10 can be lowered to a position at most as low as the upper end 81a of the main body 81. This allows the height dimension of the case 10 to be reduced.

[0039] In this embodiment, the height dimension L1 at the inner diameter of the flat portion 83 is set to be smaller than the inner diameter D1 of the main body portion 81, and the width dimension L2 at the inner diameter of the flat portion 83 is set to be larger than the inner diameter D1. Accordingly, by making the height dimension L1 at the inner diameter of the flat portion 83 smaller than the inner diameter D1 of the main body portion 81 and making the width dimension L2 at the inner diameter of the flat portion 83 larger than the inner diameter D1, it is possible to ensure that the volume of the flat portion 83 is a predetermined size and to prevent a significant decrease in the flow rate of the fluid introduced into the case 10.

[0040] Furthermore, according to this embodiment, by setting the height dimension L1 of the inner diameter of flat portion 83 to be approximately 1 / 10 to approximately 1 / 2 times the inner diameter D1 of the cylindrically formed main body portion, the height dimension of flat portion 83 at the outer diameter can be easily reduced accordingly. This allows the dimension in height direction Z of suction opening 34 to which flat portion 83 is connected to be reduced, and further allows the space in case 10 required for the above-mentioned brazing and the like to be reduced. Therefore, compared to when suction fitting 80 is formed only from main body portion 81, the height dimension of the connection portion between suction fitting 80 and case 10 can be approximately 10% to approximately 50% of that of main body portion 81. Furthermore, by reducing the height dimension of the connection portion, the height dimension of case 10 can be reduced accordingly. In this case, by setting the width dimension L2 of the inner diameter of the flat portion 83 to be approximately 6 / 5 times or more and approximately 15 / 2 times or less the inner diameter D1, the volume of the flat portion 83 is maintained at a predetermined size, and a significant reduction in the flow rate of the fluid introduced into the case 10 can be prevented.

[0041] Furthermore, in this embodiment, the width dimension W of the second introduction flow path 52 (inlet) is set to be the same as or larger than the width dimension L2 at the inner diameter of the flat portion 83. Specifically, the width dimension W is set to be approximately 1 to 10 / 3 times the width dimension L2 (approximately 100% to 333% of the width dimension L2). Therefore, the fluid introduced into the case 10 through the flat portion 83 flows through the wide second introduction flow path 52 (inlet), which has a width dimension W that is larger in the range of approximately 1 to 10 / 3 times the width dimension L2 at the inner diameter of the flat portion 83, making it easier to ensure the flow rate of the fluid introduced into the case 10.

[0042] In this embodiment, the width W of the second inlet flow path 52 is set to be approximately 10 times or more and approximately 150 times or less (approximately 1000% to approximately 15000%) the height H of the inlet flow path 52. This makes it easier to ensure the flow rate of the fluid, reduces the amount of expansion of the expansion portion, and enables the height of the centrifugal pump 1 to be reduced.

[0043] In the present embodiment, the inner diameter D2 of the communication hole 43 is set to be equal to or larger than the width dimension L2 of the inner diameter of the flat portion 83. Specifically, the inner diameter D2 is set to be approximately 1 to 5 times the width dimension L2 (approximately 100% to 500%). As a result, the fluid introduced into the case 10 from the suction opening 34 flows through the second introduction flow path 52, which has a width equal to or wider than the inner diameter of the flat portion 83, and then flows through the communication hole 43 into the accommodating space 60. At this time, the fluid flows through the communication hole 43, which has an inner diameter D2 that is larger than the width dimension L2 of the inner diameter of the flat portion 83 and is within a range of approximately 1 to 5 times the width dimension L2 of the inner diameter of the flat portion 83. Therefore, the fluid can flow from the second introduction flow path 52 to the accommodating space 60 while maintaining a sufficient flow rate.

[0044] In addition, in this embodiment, the suction fitting 80 is provided with a connecting portion 82 that connects the main body portion 81 and the flat portion 83, and the upper side Z1 portion (one side portion in a predetermined direction) and the lower side Z2 (the other side portion) of the inner wall of the connecting portion 82 have a tapered shape that gradually approaches each other from the main body portion 81 toward the flat portion 83. With this configuration, by providing the connecting portion 82 with the tapered upper side Z1 portion and the lower side Z2 portion of the inner wall, it is possible to gradually change the flow rate of the fluid flowing from the main body portion 81 to the flat portion 83. This makes it possible to reduce pressure loss due to a sudden change in the flow rate of the fluid flowing through the suction fitting 80, and to stabilize the operation of the centrifugal pump 1.

[0045] The embodiments and modifications of the present invention have been described in detail above with reference to the drawings, but the specific configurations are not limited to these embodiments, and the present invention also includes design changes and the like that do not deviate from the gist of the present invention. [Explanation of symbols]

[0046] L axis X orthogonal direction Z height direction 1. Centrifugal pump 10 cases 34 Intake opening 70 Impeller 80 Intake joint 81 Main body 83 Flat part

Claims

1. A centrifugal pump comprising a cylindrical case extending in an axial direction and an impeller housed in the case, The case is provided with an intake opening that opens in a direction perpendicular to the axial direction, an intake joint communicating with the inside and outside of the case is connected to the intake opening; The suction joint includes a cylindrical main body portion and a cylindrical flat portion that is flat in a predetermined direction and is inserted into the suction opening, The axial direction is a height direction, the main body portion and the flat portion have a coaxial central axis, and one side and the other side in the height direction of a cross section cut in the height direction have a shape that is plane-symmetrical with respect to the central axis, an upper end of the main body is located at the same position as or below an upper end of the case in the height direction; A centrifugal pump, characterized in that an upper end of the flat portion is located between an upper end of the main body portion and the central axis.

2. a height dimension L1 of the flat portion at an inner diameter thereof is smaller than an inner diameter D1 of the main body portion; 2. The centrifugal pump according to claim 1, wherein a width dimension L2 of the flat portion, which is a dimension of the inner diameter of the flat portion in a direction intersecting the height direction, is larger than the inner diameter D1.

3. the case is provided with a top wall portion extending in the perpendicular direction, a bulging portion bulging outward in the height direction from the top wall portion and having a predetermined width, and a blade case at least a part of which faces the bulging portion in the height direction within the case, an inlet port serving as a flow path for the fluid flowing in from the suction opening is formed between the bulging portion and the blade case, 3. The centrifugal pump according to claim 2, wherein a width dimension W of the inlet is equal to or greater than the width dimension L2 of the inner diameter of the flat portion.

4. The impeller case divides the interior of the case into the inlet and an accommodation space that accommodates the impeller, the blade case is provided with a communication hole that communicates the inlet with the accommodation space, 4. The centrifugal pump according to claim 3, wherein an inner diameter D2 of the communication hole is equal to or larger than the width L2 of the inner diameter of the flat portion.

5. The suction joint is provided with a connection portion that connects the main body portion and the flat portion, A centrifugal pump as described in any one of claims 1 to 4, characterized in that the one side portion and the other side portion of the inner wall of the connection portion in the specified direction have a tapered shape that gradually approaches each other as they move from the main body portion to the flat portion.

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