JP7249795B2 - double casing pump - Google Patents

Description

The present invention relates to double casing pumps.

2. Description of the Related Art As one type of pump, there is known a device called a slurry pump for pressure-feeding a fluid in which a solid and a liquid are mixed, such as slurry. This type of pump often has a double casing in order to prevent the inner surface of the casing from being worn when the slurry flows (see, for example, Patent Document 1 below). The inner casing is made of a material with excellent abrasion resistance, and the outer casing is made of a material with high strength to ensure pressure resistance. The inner casing is generally fixed to the outer casing by, for example, bolts and nuts. That is, the inner casing is rigidly connected to the outer casing.

JP 2011-169328 A

However, when the inner casing is rigidly connected to the outer casing by bolts as described above, stress concentrates on the bolted joints. As a result, the inner casing may be cracked or damaged starting from the point where the stress is concentrated, which may hinder the stable operation of the pump.

SUMMARY OF THE INVENTION An object of the present invention is to provide a double casing pump that can be operated more stably.

A double casing pump according to an aspect of the present invention includes an impeller rotatable around an axis, an inner casing covering the impeller from the outside and forming a flow path for fluid flow, and the above- described An outer casing that covers the inner casing from the outside via a pressure space into which fluid flows , and a support device that supports the inner casing in a relatively movable state with respect to the outer casing.

According to the above configuration, the inner casing is supported by the supporting device so as to be relatively movable with respect to the outer casing. Therefore, even if stress is generated between the inner casing and the outer casing, the stress generated between the inner casing and the outer casing can be relieved by a slight relative movement of the inner casing.

In the double casing pump, the support device includes a high ductility member provided on at least a part of the inner casing and having higher ductility than the inner casing, and a high ductility member having one end fixed to the outer casing and the other end to the a rod-shaped member abutting against the highly ductile member, the outer casing is formed with a through-hole through which the rod-shaped member is inserted, and a female screw is formed in at least a part of the through-hole in the extending direction. , The rod-shaped member may have a piece formed with a male thread that meshes with the female thread, and a shaft extending from the piece to the highly ductile member.

According to the above configuration, the piece portion of the rod-shaped member is fixed to the through hole of the outer casing by a screw, and the other end of the shaft portion is in contact with the highly ductile member provided in the inner casing. Therefore, when stress is generated between the shaft portion and the highly ductile member, the stress can be released by preferentially deforming the highly ductile member by being pressed by the shaft portion.

In the above double casing pump, the support device has a rod-shaped member whose one end is fixed to the outer casing and whose other end abuts against the inner casing. A hole is formed, and a female screw is formed in at least a part of the through hole in the extending direction. A shaft portion positioned on the casing side and an elastic member provided between the piece portion and the shaft portion may be provided.
A double casing pump according to one aspect of the present invention includes an impeller rotatable about an axis, an inner casing covering the impeller from the outside and forming a flow path for a fluid, and a space between the inner casing. and a support device for supporting the inner casing in a state in which the inner casing is relatively movable with respect to the outer casing, wherein one end of the support device is attached to the outer casing. A rod-shaped member is fixed and the other end abuts against the inner casing. The outer casing is formed with a through-hole through which the rod-shaped member is inserted. A screw is formed, and the rod-shaped member is composed of a piece formed with a male screw that meshes with the female screw, a shaft positioned on the inner casing side of the piece, and the piece and the shaft. and a resilient member provided therebetween.

According to the above configuration, the piece portion of the rod-shaped member is fixed to the through hole of the outer casing by the screw, and the elastic member is interposed between the shaft portion and the piece portion. Therefore, when stress is generated between the inner casing and the shaft portion, the elastic member is pressed by the shaft portion and the piece portion and is preferentially deformed, thereby releasing the stress.

In the above double casing pump, the inner casing has an annular shape centered on the axis and includes an inner casing main body in which a mounting hole centered on the axis is formed; and a disc-shaped back piece attached from Extending outward, the rod member may extend in the axial direction to press the back piece against the inner casing body.

According to the above configuration, the outer peripheral surface of the back piece and the inner peripheral surface of the mounting hole extend from the radially inner side to the outer side in the axial direction from one side to the other side. Furthermore, the rod-shaped member of the support device extends in the axial direction. As a result, the bar member presses the back piece against the inner casing main body from the other side in the axial direction. As a result, the pressure resistance of the inner casing can be enhanced. The rear piece is provided for inserting and removing the impeller inside the inner casing main body. That is, according to the above configuration, it is possible to ensure ease of maintenance while improving the pressure resistance of the inner casing.

In the above double casing pump, the inner diameter dimension of the through hole in the region corresponding to the shaft portion may be larger than the outer diameter dimension of the shaft portion.
A double casing pump according to one aspect of the present invention includes an impeller rotatable about an axis, an inner casing covering the impeller from the outside and forming a flow path for a fluid, and a space between the inner casing. and a support device for supporting the inner casing in a state in which the inner casing is relatively movable with respect to the outer casing, wherein the support device includes at least one of the inner casings. and a rod-shaped member having one end fixed to the outer casing and the other end abutting against the high ductility member; is formed with a through-hole through which the rod-shaped member is inserted, a female thread is formed at least partially in the direction in which the through-hole extends, and the rod-shaped member is formed with a male thread that meshes with the female thread. It has a piece and a shaft extending from the piece to the high ductility member, and the inner diameter of the through hole in the region corresponding to the shaft is larger than the outer diameter of the shaft.

According to the above configuration, the inner diameter dimension of the through hole in the region corresponding to the shaft portion is larger than the outer diameter dimension of the shaft portion. As a result, even if stress is applied to the shaft, the stress can be released by causing bending deformation in the shaft.

In the above double casing pump, at least one support device may be provided on both sides of the inner casing in the axial direction.

According to the above configuration, at least one support device is provided on both sides in the axial direction across the inner casing. As a result, the inner casing can be evenly supported from both sides in the axial direction. As a result, the pressure resistance of the inner casing can be further enhanced.

ADVANTAGE OF THE INVENTION According to this invention, the double casing pump which can operate more stably can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal cross-sectional view which shows the structure of the double casing pump which concerns on 1st embodiment of this invention. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1; It is an expanded sectional view showing composition of a support device concerning a first embodiment of the present invention. FIG. 5 is an enlarged cross-sectional view showing the configuration of a support device according to a second embodiment of the present invention; It is an expanded sectional view which shows the modification of the support apparatus which concerns on 2nd embodiment of this invention.

[First embodiment]
A first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. The double casing pump 100 according to the present embodiment is used for pumping fluid in which solid and liquid are mixed, such as slurry. As shown in FIG. 1, this double casing pump 100 includes a rotating shaft 1, an impeller 2, an inner casing 3, an outer casing 4, and a support device 5.

The rotating shaft 1 has a cylindrical shape extending along the axis Ac. An impeller 2 is fitted on the outer peripheral surface of the rotating shaft 1 . The impeller 2 has a disk-shaped disk 21 centered on the axis Ac, a plurality of blades 22 provided on one side of the disk 21 , and a cover 23 covering the blades 22 . The plurality of blades 22 are arranged radially around the axis Ac. Each blade 22 is curved from the radially inner side to the outer side as it goes from one side to the other side in the direction of the axis Ac. The cover 23 has a funnel shape covering the blades 22 from one side in the direction of the axis Ac. A pair of adjacent blades 22, cover 23, and disk 21 define an impeller flow path Pi.

A pointed spinner 24 is attached to one end of the rotating shaft 1 in the direction of the axis Ac. The spinner 24 gradually expands in diameter from one side in the direction of the axis Ac toward the other side. The other end of the spinner 24 in the direction of the axis Ac is smoothly connected to the disk 21 of the impeller 2 .

The impeller 2 is covered with an inner casing 3 from the outside. The inner casing 3 has a cylindrical inner casing main body 31 centered on the axis Ac, a disk-shaped back piece 32 attached to the inner casing main body 31 , and an annular liner ring 33 . The inner casing main body 31 is integrally formed with an inner casing outer peripheral portion 34 that faces the outlet (diametrically outer opening) of the impeller flow path Pi described above from the outside in the radial direction, and on one side of the inner casing outer peripheral portion 34 in the direction of the axis line Ac. and an attached inner casing front portion 35 . The inner casing outer peripheral portion 34 defines a radially expanding space between it and the outlet of the impeller flow path Pi. This space serves as a fluid channel Pf (channel) through which fluid flows. The inner casing front portion 35 covers the fluid flow path Pf and the cover 23 of the impeller 2 from one side in the direction of the axis Ac. The liner ring 33 covers the edge on the inner peripheral side of the inner casing front face portion 35 from one side in the direction of the axis Ac.

A circular opening (mounting hole H) centered on the axis Ac is formed on the other side of the inner casing main body 31 in the direction of the axis Ac. The opening diameter of this mounting hole H is set larger than the outer diameter dimension of the impeller 2 . A disk-shaped back piece 32 centered on the axis Ac is attached to the attachment hole H. As shown in FIG. That is, when replacing or repairing the impeller 2, the back piece 32 can be removed. An outer peripheral surface S1 of the back piece 32 and an inner peripheral surface S2 of the mounting hole H are tapered. More specifically, in a cross-sectional view including the axis Ac, the outer peripheral surface S1 of the back piece 32 and the inner peripheral surface S2 of the mounting hole H extend from the radially inner side to the outer side in the direction of the axis Ac from one side to the other side. extending towards. The outer peripheral surface S1 and the inner peripheral surface S2 are in contact with each other without a gap. A first insertion hole 32</b>H through which the rotating shaft 1 is inserted is formed in the central portion (position of the axis Ac) of the back piece 32 . A circular positioning recess 61 recessed toward one side in the direction of the axis Ac is formed on the surface of the back piece 32 on the other side in the direction of the axis Ac with the first insertion hole 32H as the center.

Further, the back piece 32 is provided with a plurality of first protrusions P1 along a circle centered on the axis Ac. Each first protrusion P1 protrudes from the back piece 32 toward the other side in the direction of the axis Ac. The inner casing front face portion 35 is provided with a plurality of second protrusions P2 along a circle centered on the axis Ac. Each of the second protrusions P2 protrudes from the inner casing front face portion 35 toward one side in the direction of the axis Ac. The first protrusion P1 and the second protrusion P2 are provided to support the inner casing 3 by the support device 5, which will be described later in detail.

The inner surface of the inner casing 3 configured as described above may be worn when a fluid containing solid components such as slurry flows. Therefore, in this embodiment, the inner casing 3 is made of a highly wear-resistant material. Specifically, high-Cr cast iron is suitably used as such a material.

The inner casing 3 is covered from the outside by an outer casing 4 . The outer casing 4 has an outer casing main body 41 and an outer casing cover 42 . The outer casing main body 41 abuts on the back piece 32 of the inner casing 3 from the other side in the direction of the axis Ac. The outer casing main body 41 has a disc shape centered on the axis Ac. A second insertion hole 41H through which the rotating shaft 1 is inserted is formed in the central portion (position of the axis Ac) of the outer casing main body 41 . A circular positioning projection 62 protruding toward one side in the direction of the axis Ac is provided on the surface of the outer casing main body 41 on the one side in the direction of the axis Ac, centering on the second insertion hole 41H. The positioning protrusion 62 fits into the positioning recess 61 formed in the back piece 32 described above.

A plurality of first recesses R1 arranged along a circle centered on the axis Ac are formed on the further outer peripheral side of the positioning projection 62 . The first protrusions P1 described above are fitted into the respective first recesses R1. A first through hole H1 communicating between the inside and the outside of the outer casing main body 41 is formed in the bottom surface of the first recess R1 (the surface on the other side in the direction of the axis Ac). A rod-shaped member 51 of the support device 5, which will be described later, is inserted through the first through hole H1.

The outer casing cover 42 accommodates the inner casing 3 and the impeller 2 between itself and the outer casing main body 41 . The outer casing cover 42 includes a cylindrical outer casing cover outer peripheral portion 42A centered on the axis Ac, an outer casing cover front face portion 42B integrally provided on one side of the outer casing cover outer peripheral portion 42A in the direction of the axis Ac, and an intake cylinder portion 42C. A radially expanding space (pressure space Vp) is defined between the inner peripheral surface of the outer casing cover outer peripheral portion 42A and the inner casing 3 . In addition, a part of the outer casing cover outer peripheral portion 42A in the circumferential direction is provided with a discharge tube portion 4E that communicates the inside and the outside of the outer casing 4 with each other.

The outer casing cover front portion 42B has a disc shape centered on the axis Ac, and covers the pressure space Vp and the inner casing 3 from one side in the direction of the axis Ac. A cylindrical air intake portion 42C centered on the axis Ac is provided integrally with the surface of the outer casing cover front portion 42B on one side in the direction of the axis Ac. The intake cylinder portion 42C is provided to guide fluid from the outside, and communicates with the inlet of the impeller flow path Pi described above. A tubular intake passage piece 7 made of a highly wear-resistant material (eg, high-Cr cast iron) is attached to the inner peripheral surface of the intake cylinder portion 42C.

A plurality of second recesses R2 arranged along a circle centered on the axis Ac are formed on the further outer peripheral side of the intake cylinder portion 42C. The second protrusions P2 described above are fitted into the respective second recesses R2. A second through hole H2 that communicates the inside and the outside of the outer casing main body 41 is formed in the bottom surface of the second recess R2 (the surface on one side in the direction of the axis Ac). A rod-shaped member 51 of the support device 5, which will be described later, is inserted through the second through hole H2.

The outer casing 4 configured as described above is made of a material having higher pressure resistance than the material of which the inner casing 3 is made. More specifically, the outer casing 4 is made of a metal material having higher fracture toughness than the material forming the inner casing 3 .

Next, referring to FIG. 2, the relationship between the discharge tube portion 4E and the inner casing 3 will be described. As shown in the figure, an inner discharge tubular portion 3E that communicates the inside and outside of the inner casing 3 is further provided at a part of the inner casing 3 in the circumferential direction. The inner discharge tube portion 3E is provided at a position corresponding to the discharge tube portion 4E provided on the outer casing 4 in the circumferential direction. The inner discharge tubular portion 3E extends in the tangential direction of the inner casing 3 when viewed from the direction of the axis Ac. A gap g is formed between the inner discharge cylinder portion 3E and the discharge cylinder portion 4E.

The configuration of the support device 5 will be described with reference to FIG. The support device 5 supports the inner casing 3 so as to be slightly movable relative to the outer casing 4 . As shown in the figure, the support device 5 includes a highly ductile member M attached to a portion of the inner casing 3, and a first through hole H1 formed in the outer casing main body 41 (or formed in the outer casing cover 42). and a rod-shaped member 51 that is inserted through the second through hole H2). In this embodiment, as shown in FIG. 1, support devices 5 are provided on both sides of the inner casing 3 in the direction of the axis Ac. Since these support devices 5 have the same configuration, the support device 5 provided on one side of the inner casing 3 in the direction of the axis Ac will be described as a representative.

A highly ductile member M is attached to the above-mentioned first protrusion P1 of the inner casing 3 . Specifically, the high ductility member M is embedded in the surface of the first protrusion P1 facing one side in the direction of the axis Ac. The highly ductile member M is a material exhibiting higher ductility and elasticity than the material forming the inner casing 3, and is made of, for example, a resin such as rubber or polypropylene, or a relatively soft metal such as lead or copper. It is

The rod-shaped member 51 extends in the direction of the axis Ac, and one end of the rod-shaped member 51 is fixed to the outer casing 4 by being inserted into the first through hole H1. Specifically, the rod-shaped member 51 has a piece portion 51A and a shaft portion 51B. The piece portion 51A has a rod shape extending along the axis Ac, and a male screw Sm is formed on the outer peripheral surface thereof. A female thread Sf that meshes with the male thread Sm is formed in a portion of the first through hole H1 that includes one end in the direction of the axis Ac. That is, the piece portion 51A can be fixed to the outer casing 4 by these screws. One end of the shaft portion 51B is connected to the other side of the piece portion 51A in the direction of the axis Ac. The shaft portion 51B has a rod shape with a smaller diameter than the piece portion 51A. The outer diameter dimension of the shaft portion 51B is set smaller than the inner diameter dimension of the first through hole H1. The other end of the shaft portion 51B is in contact with the high ductility member M described above. That is, the shaft portion 51B extends from the piece portion 51A to the high ductility member M.

Furthermore, in the present embodiment, in order to prevent the fluid from leaking out from the inside of the outer casing 4 (the pressure space Vp) through the first through hole H1, the end of the first through hole H1 on the other side in the direction of the axis Ac is provided with A seal portion 8 is provided. The seal portion 8 has an annular O-ring 81 that surrounds the shaft portion 51B from the outer peripheral side, and a holding portion 82 that holds the O-ring 81 inside the first through hole H1.

Next, the operation of the double casing pump 100 will be described. In operating the double casing pump 100, the rotary shaft 1 is rotated around the axis Ac by an external drive source (such as an electric motor). As the rotating shaft 1 rotates, the impeller 2 rotates. As the impeller 2 rotates, a fluid (slurry as an example) is introduced into the impeller passage Pi through the intake cylinder portion 42C. The fluid is given centrifugal force when passing through the impeller flow path Pi, and flows radially outward in a state where the pressure increases, and reaches the above-described fluid flow path Pf. The fluid that has passed through the fluid flow path Pf is pressure-fed to the outside through the inner discharge tube portion 3E and the discharge tube portion 4E. At this time, part of the fluid also flows into the space (pressure space Vp) in the outer casing 4 through the gap g between the inner discharge cylinder part 3E and the discharge cylinder part 4E.

Here, if the inner casing 3 is rigidly connected to the outer casing 4 by, for example, bolts instead of the supporting device 5, stress is concentrated on the joints by the bolts. As a result, the inner casing 3 may be cracked or damaged starting from the point where the stress is concentrated, which may hinder the stable operation of the pump. Therefore, in this embodiment, the support device 5 described above supports the inner casing 3 so as to be relatively movable with respect to the outer casing 4 .

According to the above configuration, the inner casing 3 is supported by the support device 5 so as to be relatively movable with respect to the outer casing 4 . Therefore, even if stress is generated between the inner casing 3 and the outer casing 4, the stress generated between the inner casing 3 and the outer casing 4 can be released by a slight relative movement of the inner casing 3. .

In particular, according to the above configuration, the piece portion 51A of the rod-shaped member 51 is fixed by screws to the first through hole H1 (or the second through hole H2) of the outer casing 4, and the other end of the shaft portion 51B is It abuts on a highly ductile member M provided on the inner casing 3 . Therefore, when stress occurs between the shaft portion 51B and the high ductility member M, the stress can be released by preferentially deforming the high ductility member M by being pressed by the shaft portion 51B.

Furthermore, according to the above configuration, the outer peripheral surface S1 of the back piece 32 and the inner peripheral surface S2 of the mounting hole H extend from the radially inner side to the outer side in the direction of the axis Ac from one side to the other side. . Furthermore, a rod-shaped member 51 of the support device 5 extends in the direction of the axis Ac. As a result, the bar member 51 presses the back piece 32 against the inner casing main body 31 from the other side in the direction of the axis Ac. As a result, the pressure resistance of the inner casing 3 can be enhanced. The back piece 32 is provided for taking the impeller 2 into and out of the inner casing main body 31 . That is, according to the above configuration, it is possible to improve the pressure resistance of the inner casing 3 and ensure ease of maintenance.

In addition, according to the above configuration, the inner diameter dimension of the through hole in the region corresponding to the shaft portion 51B is larger than the outer diameter dimension of the shaft portion 51B. As a result, even if stress is applied to the shaft portion 51B, the stress can be released by causing bending deformation in the shaft portion 51B.

According to the above configuration, at least one support device 5 is provided on both sides of the inner casing 3 in the direction of the axis Ac. As a result, the inner casing 3 can be evenly supported from both sides in the direction of the axis Ac. As a result, the pressure resistance of the inner casing 3 can be further enhanced.

The first embodiment of the present invention has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present invention. For example, in the above-described embodiment, the rod member 51 of the support device 5 is fixed by screws formed in the first through holes H1 (second through holes H2). However, the structure for fixing the rod-shaped member 51 is not limited to screws, and as other examples, it is also possible to use a fixing structure by snap fit or welding.

[Second embodiment]
Next, a second embodiment of the invention will be described with reference to FIG. In addition, the same code|symbol is attached|subjected about the structure similar to said 1st embodiment, and detailed description is abbreviate|omitted. As shown in FIG. 4, in this embodiment, the piece portion 251A and the shaft portion 251B of the rod-shaped member 251 are formed separately from each other rather than integrally. The shaft portion 251B has a rod-shaped shaft portion main body 252 extending along the axis Ac and a disk-shaped receiving portion 253 provided on one end side of the shaft portion main body 252 . A space is formed between the receiving portion 253 and the piece portion 251A, and the elastic member 9 is arranged in this space. A plurality of disc springs are used as the elastic member 9 in this embodiment. Each disk spring biases the shaft portion 251B in the direction of the axis Ac against the piece portion 251A.

According to the above configuration, the piece portion 251A of the rod-shaped member 251 is fixed by screws to the first through hole H1 (or the second through hole H2) of the outer casing 4, and the shaft portion 251B and the piece portion 251A are fixed by screws. An elastic member 9 is interposed therebetween. Therefore, when stress is generated between the inner casing 3 and the shaft portion 251B, the elastic member 9 is pressed by the shaft portion 251B and the bridge portion 251A and is preferentially deformed, thereby releasing the stress. can be done.

The second embodiment of the present invention has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present invention. For example, as shown in FIG. 5, in the above-described second embodiment, it is possible to employ a configuration in which the high ductility member M is not provided on the inner casing 3 side. With such a configuration as well, stress concentration occurring between the inner casing 3 and the outer casing 4 can be suppressed by the elastic member 9 described above.

DESCRIPTION OF SYMBOLS 1... Rotating shaft 2... Impeller 3... Inner casing 4... Outer casing 5... Support device 7... Air intake passage piece 8... Seal part 9... Elastic member 21... Disc 22... Blade 23... Cover 24... Spinner 31... Inner casing main body 32 Rear piece 33 Liner ring 34 Inner casing outer peripheral portion 35 Inner casing front face portion 41 Outer casing main body 42 Outer casing cover 51 Bar member 61 Positioning recess 62 Positioning projection 81 O-ring 82 Holding portion 100 Double casing pump 251 Rod-like member 252 Shaft main body 253 Receiving portion 251A Piece portion 251B Shaft portion 32H First insertion hole 3E Inner discharge cylindrical portion 41H Second insertion hole 42A Outer casing cover outer circumference Part 42B... Outer casing cover front part 42C... Intake cylinder part 4E... Exhaust cylinder part 51A... Piece part 51B... Shaft part Ac... Axis line g... Gap H... Mounting hole H1... First through hole H2... Second through hole M... High ductility member P1 First protrusion P2 Second protrusion Pf Fluid flow path Pi Impeller flow path R1 First recess R2 Second recess S1 Outer peripheral surface S2 Inner peripheral surface Sf Female screw Sm Male screw Vp…Pressure space

Claims (8)

an impeller rotatable about its axis;
an inner casing that covers the impeller from the outside and forms a flow path through which fluid flows;
an outer casing that covers the inner casing from the outside via a pressure space between the inner casing and the fluid that flows ;
a support device that supports the inner casing in a relatively movable state with respect to the outer casing;
double casing pump. The support device is
a highly ductile member provided on at least a portion of the inner casing and having higher ductility than the inner casing;
A rod-shaped member having one end fixed to the outer casing and the other end abutting against the high ductility member;
has
The outer casing is formed with a through-hole through which the rod-shaped member is inserted,
A female screw is formed at least partially in the direction in which the through hole extends,
The rod-shaped member is
a piece portion having a male screw that meshes with the female screw;
a shaft portion extending from the piece portion to the high ductility member;
A dual casing pump according to claim 1, comprising: The support device has a rod-shaped member whose one end is fixed to the outer casing and whose other end abuts the inner casing,
The outer casing is formed with a through-hole through which the rod-shaped member is inserted,
A female screw is formed at least partially in the direction in which the through hole extends,
The rod-shaped member is
a piece portion having a male screw that meshes with the female screw;
a shaft portion positioned on the inner casing side of the piece portion;
an elastic member provided between the piece portion and the shaft portion;
A dual casing pump according to claim 1, comprising: an impeller rotatable about its axis;
an inner casing that covers the impeller from the outside and forms a flow path through which fluid flows;
an outer casing covering the inner casing from the outside with a space between the inner casing and the inner casing;
a support device that supports the inner casing in a relatively movable state with respect to the outer casing;
with
The support device has a rod-shaped member whose one end is fixed to the outer casing and whose other end abuts the inner casing,
The outer casing is formed with a through-hole through which the rod-shaped member is inserted,
A female screw is formed at least partially in the direction in which the through hole extends,
The rod-shaped member is
a piece portion having a male screw that meshes with the female screw;
a shaft portion positioned on the inner casing side of the piece portion;
an elastic member provided between the piece portion and the shaft portion;
double casing pump. The inner casing is
an inner casing body having an annular shape centered on the axis and having a mounting hole centered on the axis;
a disk-shaped back piece attached to the attachment hole from the axial direction;
has
the inner peripheral surface of the mounting hole and the outer peripheral surface of the back piece extend from the inner side to the outer side in the radial direction with respect to the axial line from one side to the other side in the axial direction;
5. The double casing pump according to any one of claims 2 to 4 , wherein the rod member extends in the axial direction to press the back piece against the inner casing main body. The double casing pump according to any one of claims 2 to 5 , wherein an inner diameter dimension of the through hole in a region corresponding to the shaft portion is larger than an outer diameter dimension of the shaft portion. an impeller rotatable about its axis;
an inner casing that covers the impeller from the outside and forms a flow path through which fluid flows;
an outer casing covering the inner casing from the outside with a space between the inner casing and the inner casing;
a support device that supports the inner casing in a relatively movable state with respect to the outer casing;
with
The support device is
a highly ductile member provided on at least a portion of the inner casing and having higher ductility than the inner casing;
A rod-shaped member having one end fixed to the outer casing and the other end abutting against the high ductility member;
has
The outer casing is formed with a through-hole through which the rod-shaped member is inserted,
A female screw is formed at least partially in the direction in which the through hole extends,
The rod-shaped member is
a piece portion having a male screw that meshes with the female screw;
a shaft portion extending from the piece portion to the high ductility member;
has
An inner diameter dimension of the through hole in a region corresponding to the shaft portion is larger than an outer diameter dimension of the shaft portion.
Double casing pump. 8. The double casing pump according to any one of claims 1 to 7 , wherein at least one support device is provided on each side in the axial direction across the inner casing.

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