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 in a 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 outside 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 desired to reduce the size of the case in a predetermined direction due to the installation space. However, in the case of the centrifugal pump described above, a space equal to or larger than the diameter of the suction side coupling member must be secured at the mounting portion of the suction side coupling member as a space for mounting the suction side coupling member, which makes it difficult to reduce the size of the case in the predetermined direction.

[0005] An object of the present invention is to provide a centrifugal pump capable of reducing the size of the case in a predetermined direction. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the above objects, 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 an intake opening that opens in a direction perpendicular to the axial direction, and an intake fitting that communicates with the inside and outside of the case is connected to the intake opening, and the intake fitting comprises a cylindrical main body portion and a cylindrical flat portion that is flat in a predetermined direction and is inserted into the intake opening.

[0007] According to the present invention, by providing a flat portion in the suction joint, the dimension in a predetermined direction of the connection portion between the suction joint and the case can be reduced compared to the case of using a cylindrical suction joint with a fixed diameter. Specifically, for example, a flat portion formed by crushing one end of the main body of the suction joint in a predetermined direction can reduce the dimension of the suction joint side in the predetermined direction, and accordingly the dimension in the predetermined direction of the periphery of the suction opening to which the suction joint is connected, i.e., the case side can be reduced. By reducing the dimension in the predetermined direction of the connection portion between the suction joint and the case, the dimension in the predetermined direction of the case can be reduced accordingly. Thus, 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 the height direction may be the direction of the rotation axis of the impeller, which affects the dimensions of the case, and the height dimension of the case may be large. For this reason, it is preferable that the flat part of the suction joint has a flat cylindrical shape whose height dimension is smaller than its width dimension in its outer shape. In this case, the height dimension of the connection part between the suction joint and the case can be reduced, and the height dimension of the case can be reduced accordingly. However, the rotation axis of the impeller is not limited to the height direction, and may be arranged in a predetermined direction that is horizontal or inclined. In this case, by making the flat part flat and cylindrical in the predetermined direction, the dimension of the case in that direction can be shortened.

[0009] Moreover, the axial direction is the height direction, the main body and the flat part have a coaxial central axis, one side and the other side of the cross section cut in the height direction have a shape symmetrical with respect to the central axis, the upper end of the main body 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 part is preferably located between the upper end of the main body and the central axis. In a centrifugal pump, it is sometimes desired to reduce the height dimension of the case due to the installation space, and with such a configuration, for example, the flat part can be easily formed by deforming one end of the main body, which has a constant diameter, so as to be crushed evenly in the height direction, as an example of a predetermined direction. And, since the upper end of the flat part is located between the upper end of the main body and the central axis, a space in the height direction is generated between the upper end of the flat part and the upper end of the main body, and this space can be used as a space when connecting the case and the flat part by welding, brazing, etc. Therefore, there is no need to provide a connection allowance for the above-mentioned welding or brazing above the upper end of the main body (i.e., the upper end of the suction joint) on the case side, and the upper end of the case can be set at a lower position accordingly. According to the above configuration, the upper end of the case can be lowered to the same position as the upper end of the main body at the maximum. This makes it possible to reduce the height dimension of the case.

[0010] In addition, 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, which is the dimension of the inner diameter of the flat portion in the direction intersecting the height direction, is larger than the inner diameter D1. In a centrifugal pump, it is possible to reduce the overall diameter dimension of the suction joint with a constant diameter dimension and reduce the dimension of the case to which it is connected in a predetermined direction accordingly, but in this case, the flow rate of the fluid introduced into the case may be significantly reduced, and the performance of the centrifugal pump may be deteriorated. However, according to the configuration of the present invention, the height dimension L1 of the inner diameter of the flat portion is smaller than the inner diameter D1 of the main body portion, while the width dimension L2 of the inner diameter of the flat portion is larger than the inner diameter D1, thereby ensuring the volume of the flat portion at a predetermined size and suppressing a significant reduction in the flow rate of the fluid introduced into the case.

[0011] 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, and an inlet is formed between the bulging portion and the blade case as a flow path for the fluid flowing in from the suction opening, and the width dimension W of the inlet is preferably the same as or larger than the width dimension L2 at the inner diameter of the flat portion. According to 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 at the inner diameter of the flat portion, making it easier to ensure the flow rate of the fluid introduced into the case.

[0012] Moreover, the blade case divides the inside of the case into the inlet and an accommodation space that accommodates the impeller, and the blade case is provided with a communication hole that communicates 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, the 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 into the accommodation space through the communication hole. At that time, since 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 the flow rate of the fluid.

[0013] Moreover, it is preferable that the suction joint is provided with a connection part that connects the main body part and the flat part, and that the one side part and the other side part of the inner wall of the connection part have a tapered shape that gradually approaches each other from the main body part to the flat part. With this configuration, by providing a connection part in which the one side part and the other side part of the inner wall in the predetermined direction are tapered, the flow rate of the fluid flowing from the main body part to the flat part can be gradually changed. This makes it possible to reduce pressure loss due to a sudden change in the flow rate of the fluid flowing through the suction joint, and stabilize the operation of the centrifugal pump. Effect of the Invention

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

[0015] [Figure 1] 1 is a cross-sectional view of a centrifugal pump according to an embodiment of the present invention. [Diagram 2] Cross-sectional view taken along line AA in FIG. [Diagram 3] Side view of a centrifugal pump. [Figure 4] Top view of a centrifugal pump. [Diagram 5] FIG. 2 is a cross-sectional view taken along line BB in 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 suction joint, and FIG. 1B is a front view of the flat portion of the suction 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 the flat portion different from the example shown in FIG. 8(A). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 the height direction, which is indicated as the "height direction Z". One side of the height direction Z is indicated as the "upper side Z1", and the other side is indicated as the "lower side Z2". A direction perpendicular to the height direction Z is indicated as the perpendicular direction, which is indicated as the "perpendicular direction X". The perpendicular direction X is also the radial direction of the case 10. A direction intersecting the longitudinal direction of the suction joint 80 and the second introduction flow passage 52 (inlet) described later is indicated as the "width direction Y". These definitions are merely for convenience of description, and do not necessarily coincide with the directions in the actual use state of the centrifugal pump 1, and do not 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 a case 10 from a suction joint 80 to a discharge joint 90 by an impeller 70, and discharges the fluid outside the case 10.

[0017] The case 10 is made of a metal material such as SUS (stainless steel) and is formed in 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 to the lower side Z2 is formed in the center of the lower end of the first housing portion 21. The second housing portion 22 is formed to have a smaller diameter than the first housing portion 21 and houses a bush 71 described later inside. A flange portion 23 protruding radially outward is formed in the upper end of the first housing portion 21 around the entire circumference. A bracket 24 protruding radially outward from a side wall portion of the first housing portion 21 is installed on the lower side Z2 of the flange portion 23. 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 bulging portion 33 that bulges outwardly in the upper side Z1 (outwardly in the height direction Z). As shown in Figs. 3 and 4, the bulging portion 33 has a predetermined width in the width direction Y and extends from the center of the top wall portion 31 to one side in the orthogonal direction X to the outer peripheral edge of the top wall portion 31. The upper end surface 33a of the bulging portion 33 is located at the top end of the case 10 and forms the upper end surface of the case 10. The formation of the bulging portion 33 forms a second introduction flow path 52 (inlet) between the upper surface of the upper wall portion 41 of the blade case 40 (described later) and the inner surface of the bulging portion 33. An intake opening 34 and an exhaust opening 35, which open in the perpendicular direction X, are formed penetrating 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 shifted by 90° in the circumferential direction around the axis L when viewed from the axis L direction, but this angle can be changed as appropriate. An intake joint 80 is inserted and fixed in the intake opening 34. A discharge joint 90 is inserted and fixed in the exhaust 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 from the outer peripheral edge of the upper wall portion 41 to the lower side Z2 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, welding, 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 (flowing 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 introduction flow passage 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, and surrounds the accommodation space 60 in the circumferential direction, forming a reservoir portion in which the fluid introduced into the case 10 from the suction opening 34 accumulates. The second introduction flow passage 52 is formed by the space between the bulging portion 33 of the main body case 30 and the upper wall portion 41 of the blade case 40. The second introduction flow passage 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 bulging portion 33, and is defined as the height dimension H. The dimension in the width direction Y of the second introduction flow passage 52 is determined by the width dimension of the inner surface of the bulging portion 33, and is defined as the width dimension W. The second introduction flow passage 52 communicates with the accommodation space 60 through 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 the 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 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 sent by the impeller 70. 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 the flow rate.

[0021] The impeller 70 is accommodated in the accommodation space 60 in the case 10. The impeller 70 includes a bush 71 accommodated in the second accommodation portion 22 of the rotor case 20. The bush 71 is a bearing and is formed in a cylindrical shape extending in the height direction Z. A shaft 72 as a rotating shaft is inserted in the center of the bush 71 and is supported rotatably around the axis line 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 member 73 is inserted into the center of a cylindrical magnet rotor 74 and fixed to the magnet rotor 74, whereby the blade member 73 and the shaft 72 are rotatable around the axis line L in accordance with the rotation of the magnet rotor 74.

[0022] The case 10 formed as described above and accommodating the impeller 70 therein is connected to the coil unit 100. As shown in FIG. 2, the coil unit 100 includes a lower cover 2 and a coil case 3 that are combined to form a single box. A fixing protrusion 3a that protrudes radially inward is formed at the upper end of the coil case 3. The fixing protrusion 3a connects the case 10 and the coil unit 100 by engaging with the bracket 24 of the case 10 described above. A control board 4 that controls the rotation of the magnet rotor 74 and a stator coil 5 that is disposed on the upper part of the control board 4 are accommodated inside the lower cover 2 and the coil case 3. The stator coil 5 includes a cylindrical bobbin 5a extending in the orthogonal direction X, a stator core 5b that is disposed at the center of the bobbin 5a, and a winding 5c ​​that is wound around the outer periphery of the bobbin 5a. An upper cover 6 is disposed on the upper part of 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 penetrating in the height direction Z at the center of the coil unit 100 configured in this manner.

[0023] Next, the suction joint 80 will be described. The suction joint 80 is a piping member made of a metal material such as C1220T (phosphorus deoxidized copper), and includes a cylindrical main body 81 extending in the perpendicular direction X, a connecting portion 82 continuing to the main body 81, and a flat portion 83 continuing to the connecting portion 82, as shown in FIG. 7(A). The main body 81 is formed with a constant diameter, and the end opposite to 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, and the dimension in the height direction Z gradually decreases toward the flat portion 83 side, and the dimension in the width direction Y increases. As shown in FIG. 2, the upper side Z1 portion (one side portion in a predetermined direction) and the lower side Z2 portion (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 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 by, for example, deforming the main body 81 so as to be crushed in the height direction Z (a predetermined direction). The flat portion 83 is fixed to the case 10 in a sealed state by welding, brazing, or fusion while inserted into the suction opening 34, and its internal space is connected to the introduction flow passage 50 of the case 10. As a result, the suction joint 80 is connected to the inside and outside of the case 10. In this embodiment, the main body 81, the connection portion 82, and the flat portion 83 thus formed have a coaxial central axis C as shown in FIG. 2. The main body 81, the connection portion 82, and the flat portion 83 have a shape that is plane-symmetrical about the central axis C at 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.

[0025] As shown in FIG. 7B, the flattened portion 83 has an opening shape at the end opposite to the main body portion 81, which is an ellipse elongated in the width direction Y. In the present embodiment, the "flat" of the flattened portion 83 includes any portion whose dimension in the width direction Y is greater than its dimension in the height direction Z. Therefore, the opening shape of the flattened portion 83 is not limited to an ellipse elongated in the width direction Y, and can be appropriately selected. For example, as shown in FIG. 8A, the opening shape of the flattened portion 83 may be an ellipse elongated in the width direction Y, or as shown in FIG. 8B, the opening shape of the flattened portion 83 may be a rounded rectangle elongated in the width direction Y. In addition to the above, the opening shape of the flattened portion 83 may be various shapes such as a diamond shape. In addition, in this embodiment, the main body 81, the connection 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 a shape that is plane-symmetrical about the central axis C, but this is not limited thereto, and the opening shape of the flat portion 83 can also be, for example, a triangular shape that does not have a plane-symmetrical shape. In this way, the shape of the opening of the flat portion 83 can be appropriately selected from various shapes, so that 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 connection part 92, and a flat part 93, which are formed in the same manner as the suction joint 80. The flat part 93 of the discharge joint 90 is fixed to the case 10 in a sealed state by welding, brazing, or fusion while being inserted into the discharge opening 35 of the case 10, 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 part 93 abuts against the control wall 44 of the impeller case 40 described above.

[0027] The operation of the centrifugal pump 1 configured as above will be described. First, by passing a current through the stator coil 5, the stator coil 5 is excited, and the magnet rotor 74 rotates around the axis L together with the shaft 72 and the blade member 73. As a result, the fluid in the accommodation space 60 flows toward the discharge opening 35 and is 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 introduction flow path 52, the fluid flows from the second introduction flow path 52 to the accommodation space 60 through the communication hole 43. Then, the fluid flows from the first introduction flow path 51 to the second introduction flow path 52. Also, the fluid is sucked into the first introduction flow path 51 from the suction joint 80 (suction opening 34). In this way, a flow path of the fluid from the suction joint 80 to the introduction flow path 50 (first introduction flow path 51, second introduction flow path 52), the communication hole 43, the accommodation space 60, and the discharge joint 90 is formed.

[0028] In the suction joint 80 formed as described above, as shown in FIG. 2, the upper end 81a of the main body 81 is located on the lower side Z2 in the height direction Z than the upper end surface 33a of the bulging portion 33 (the other upper surface of the case 10). In addition, 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 81. As a result, 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. As a result, a space in the height direction Z is generated between the upper end 83a of the flat portion 83 and the upper end 81a of the main body 81, and this space can be used as a space when connecting the case 10 and the flat portion 83 by welding, brazing, or the like. For this reason, 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 fitting 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 on the lower side Z2 than the upper end surface 33a of the bulging portion 33 (the upper end surface of the case 10). However, 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. According to 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 allows the height dimension of the case 10 to be reduced. Specifically, the distance P1 from the central axis C to the upper end 83a of the flat portion 83 is preferably set to about 1 / 2 or less (about 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 about 1 / 4 or more (about 25% or more) the distance P2. This further preferred embodiment makes it possible to reduce the dimension of the case 10 in the height direction Z to the extent that the pressure loss does not become too large while still ensuring a sufficient connection allowance for the suction joint 80.

[0030] As shown in FIG. 2, the central axis C of the suction joint 80 may be disposed at a position facing the peripheral wall portion 42 of the blade case 40 in the orthogonal direction X. In this configuration, the suction opening 34 is formed in a portion facing the peripheral wall portion 42 of the blade case 40 in the upper portion of the case 10, 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 blade case 40, and the pressure of the fluid can be increased at the collision portion. This increases the momentum of the fluid near the suction opening 34, improves the suction pressure, and makes it easier to ensure the flow rate of the centrifugal pump 1. In addition, as described above, according to 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 blade case 40 in the orthogonal direction X, a wide space can be secured in the lower portion of the case 10 to place the coil unit 100. In this case, the upper end 83a of the flat portion 83 may be disposed so as to be at the same position as the upper surface of the upper wall portion 41 of the blade 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 bulge portion 33 can be brought closer to the blade case 40 in the height direction Z without being affected by the flat portion 83 while securing the introduction flow path 50, and the height dimension of the centrifugal pump 1 can be further reduced.

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

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

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

[0034] In terms of ensuring the flow rate, the relationship between the width dimension L2 at the inner diameter of the flattened portion 83 and the width dimension W of the second introduction flow path 52 is also important. If the width dimension W is insufficient with respect to the width dimension L2, the flow rate of the fluid in the second introduction flow path 52 will be unintentionally throttled. Here, it is preferable to set the width dimension W to be equal to or larger than the width dimension L2. Specifically, it is preferable to set the width dimension W to be approximately 1 to approximately 10 / 3 times the width dimension L2 (approximately 100% to approximately 333%), and more preferably to be 3 / 2 to 3 times the width dimension L2 (150% to 300%). This more preferable embodiment can further reduce the pressure loss near the second introduction flow path 52, and therefore can further prevent the reduction in the flow rate of the fluid.

[0035] In terms of ensuring the flow rate, the relationship between the width dimension L2 at the inner diameter of the flat portion 83 and the inner diameter D2 of the communication hole 43 of the blade case 40 is also important. If the inner diameter D2 is insufficient with respect to the width dimension L2, the flow rate of the fluid is unintentionally throttled at the communication hole 43. Here, it is preferable that the inner diameter D2 of the communication hole is the same as the width dimension L2 at the inner diameter of the flat portion or is larger than the width dimension L2. Specifically, it is preferable that the inner diameter D2 is set to about 8 mm to 15 mm. It is preferable that the inner diameter D2 is set to a size of about 1 to about 5 times the width dimension L2 (about 100% to about 500%), and it is more preferable that the inner diameter D2 is set to a size of 1.05 to about 3 times the width dimension L2 (105% to 300%). This more preferable embodiment can further reduce the pressure loss near the communication hole 43, and further prevent a reduction in the flow rate of the fluid while making the centrifugal pump 1 more compact.

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

[0037] In the centrifugal pump 1, as in this embodiment, the direction of the axis L is the height direction Z, and the height direction Z may be the direction in which the shaft 72 of the impeller 70, which affects the dimensions of the case 10, extends, and the height dimension of the case 10 may become large. For this reason, it is preferable that the flat portion 83 of the suction joint 80 has a flat cylindrical shape whose height dimension is smaller than its width dimension in its outer shape. In that case, the height dimension of the connection part between the suction joint 80 and the case 10 can be reduced, and the height dimension of the case 10 can be reduced accordingly. However, the shaft 72, which is the rotation axis of the impeller 70, may be arranged not only in the height direction Z but also in a predetermined direction that is horizontal or inclined. In that case, by making the flat portion 83 flat and cylindrical in a predetermined direction, the dimension of the case 10 in that direction can be shortened.

[0038] According to the present embodiment, the axis L direction is the height direction Z, and the main body 81 and the flat portion 83 of the suction joint 80 have a coaxial central axis C, and the upper side Z1 and the lower side Z2 of the cross section cut in the height direction Z have a shape that is symmetrical about the central axis C. In the centrifugal pump 1, it is sometimes desired to reduce the height dimension of the case 10 due to the installation space. According to the present configuration, for example, the flat portion 83 can be easily formed by deforming one end of the main body 81, which has a constant diameter dimension, so as to be uniformly crushed in the height direction Z, which is an example of a predetermined direction. 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, so that a space in the height direction Z is generated between the upper end 83a of the flat portion 83 and the upper end 81a of the main body 81, and this space can be used as a space 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, or the like on the upper side Z1 of the upper end 81a of the main body 81 (i.e., the upper end of the suction joint) on the case 10 side, 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 equal to 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. 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 while making the width dimension L2 at the inner diameter of the flat portion 83 larger than the inner diameter D1, the volume of the flat portion 83 can be secured at a predetermined size, and a significant decrease in the flow rate of the fluid introduced into the case 10 can be suppressed.

[0040] According to the present embodiment, the height dimension L1 of the inner diameter of the flat portion 83 is set to be about 1 / 10 to about 1 / 2 times the inner diameter D1 of the cylindrical main body, so that the height dimension of the outer diameter of the flat portion 83 can be easily reduced accordingly, and the dimension in the height direction Z of the suction opening 34 to which the flat portion 83 is connected can be reduced, and the space required for the above-mentioned brazing and the like in the case 10 can also be reduced. Therefore, compared to the case where the suction joint 80 is formed only from the main body 81, the height dimension of the connection portion between the suction joint 80 and the case 10 can be about 10% to about 50% of the main body 81. By reducing the height dimension of the connection portion, the height dimension of the case 10 can be reduced accordingly. In this case, by making the width dimension L2 at the inner diameter of the flat portion 83 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] In this embodiment, the width dimension W of the second introduction flow passage 52 (inlet) is set to be equal to 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 approximately 333%). Therefore, the fluid introduced into the case 10 through the flat portion 83 flows through the wide second introduction flow passage 52 (inlet) having 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 dimension W of the second inlet flow passage 52 is set to be about 10 times or more and about 150 times or less (about 1000% to about 15000%) the height dimension H of the inlet flow passage 52. This makes it easier to ensure the flow rate of the fluid, reduces the amount of expansion of the expansion portion, and reduces the height dimension of the centrifugal pump 1.

[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 (approximately 100% to approximately 500%) the width dimension L2. According to this, the fluid introduced into the case 10 from the suction opening 34 flows through the second introduction flow passage 52, which is equal to or wider than the inner diameter of the flat portion 83, and then flows into the accommodation space 60 through the communication hole 43. At that time, the fluid flows through the communication hole 43 having an inner diameter D2 larger in the range of approximately 1 to approximately 5 times the width dimension L2 of the inner diameter of the flat portion 83, so that the fluid can be made to flow from the second introduction flow passage 52 to the accommodation space 60 while ensuring the flow rate of the fluid.

[0044] In the present embodiment, the suction joint 80 is provided with a connection 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 connection 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 connection portion 82 in which the upper side Z1 portion and the lower side Z2 portion of the inner wall have a tapered shape, 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 joint 80, and to stabilize the operation of the centrifugal pump 1.

[0045] The above describes in detail the embodiments and modified examples of the present invention with reference to the drawings. However, the specific configuration is 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, A suction joint communicating with the inside and outside of the case is connected to the suction opening, A centrifugal pump, characterized in that the suction joint comprises a cylindrical main body portion and a tubular flat portion that is flat in a predetermined direction and is inserted into the suction opening.

2. 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 about 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; 2. The centrifugal pump according to claim 1, wherein an upper end of the flat portion is located between an upper end of the main body and the central axis.

3. A height dimension L1 at an inner diameter of the flat portion is smaller than an inner diameter D1 of the main body portion, 3. The centrifugal pump according to claim 2, wherein a width dimension L2, which is a dimension of an inner diameter of the flat portion in a direction intersecting the height direction, is larger than the inner diameter D1.

4. 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 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, 4. The centrifugal pump according to claim 3, wherein a width dimension W of the inlet is equal to or larger than the width dimension L2 at the inner diameter of the flat portion.

5. The impeller case divides the inside 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 between the inlet and the accommodation space, 5. The centrifugal pump according to claim 4, wherein an inner diameter D2 of the communication hole is equal to or larger than the width dimension L2 of the inner diameter of the flat portion.

6. 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 5, 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 it moves from the main body portion to the flat portion.

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