JP7624895B2 - Method for manufacturing a filter housing and a filter housing - Google Patents

Description

The present invention relates to a method for manufacturing a filter housing and a filter housing.

A filter housing for liquid filtration is known that has a disk-shaped partition member that divides the interior of the cylindrical housing into upper and lower spaces and supports multiple elongated cylindrical filter cartridges housed in the upper space (see, for example, Patent Document 1). Such filter housings are generally made of metal such as stainless steel, and the partition member is welded to the open end of the cylindrical or hemispherical housing member that constitutes the filter housing. TIG welding has traditionally been widely used as the welding method for this purpose.

JP 2014-087718 A

However, TIG welding has a low energy density, and it is difficult to penetrate to the back side of the welded surface (the inner circumference of the filter housing) in one weld, so liquid may seep into the gap that is formed and cause crevice corrosion. On the other hand, if welding is attempted from the back side to ensure sufficient penetration, the heat input becomes large, causing sensitization that reduces corrosion resistance and leads to stress corrosion cracking. On the other hand, it is possible to use other welding methods with a higher energy density than TIG welding, but simply using another welding method instead of TIG welding does not necessarily result in good penetration, and some manufacturing or design ingenuity is required.

The object of the present invention is to provide a filter housing and a manufacturing method thereof that improves the reliability of the welded joints.

In order to achieve the above-mentioned object, a method for manufacturing a filter housing of the present invention is a method for manufacturing a metal filter housing having a cylindrical or hemispherical first housing member and a disk-shaped second housing member that closes an opening of the first housing member, and in one aspect, the method includes the steps of forming an annular rib on the peripheral portion of the surface of the second housing member, the annular rib protruding in the axial direction beyond at least an area adjacent to the inner peripheral side, and butting an end portion that forms the opening of the first housing member with a tip portion of the rib and joining the butted portion by laser welding, and the step of forming the rib includes the steps of: and forming a rib along the peripheral portion by forming an annular groove in a region of the surface of the second housing member that is inner than the peripheral portion, and in another aspect, the method includes the steps of preparing a second housing member having the same diameter as that of the first housing member, forming an annular rib on the peripheral portion of the surface of the second housing member, the rib protruding in the axial direction at least further than the region adjacent to the inner side and having the same thickness as the first housing member, and butting an end portion that forms an opening of the first housing member against a tip portion of the rib and joining the butted portion by laser welding .

The filter housing of the present invention is a metal filter housing having a cylindrical or hemispherical first housing member and a disk-shaped second housing member that closes an opening of the first housing member, and in one embodiment, the second housing member has an annular rib formed on the peripheral portion of the surface of the second housing member and protruding in the axial direction beyond at least a region adjacent to the inner peripheral side, the rib being defined by an annular rib formed on a region of the surface of the second housing member that is on the inner peripheral side beyond the peripheral portion, and the first housing member and the second housing member are disposed in a first housing member. In one aspect, the first housing member and the second housing member have the same diameter, the second housing member has an annular rib formed on the peripheral portion of the surface of the second housing member, protruding axially at least beyond the area adjacent to the inner circumference and having the same thickness as the first housing member, and the first housing member and the second housing member are joined by laser welding, with the end portion forming the opening of the first housing member and the tip portion of the rib butted together .

According to this filter housing manufacturing method and filter housing, by forming an annular rib on the second housing member, it becomes possible to use laser butt welding to weld it to the first housing member. As a result, a sufficient amount of penetration can be ensured even with a smaller amount of heat input, and a good weld can be formed with reduced sensitization.

As described above, the present invention can improve the reliability of welded parts.

1 is a schematic cross-sectional view of a filter housing according to a first embodiment of the present invention. 3A to 3C are cross-sectional views showing each step of a method for manufacturing a batten according to the first embodiment of the present invention. FIG. 5 is a schematic enlarged cross-sectional view of a filter housing according to a second embodiment of the present invention.

The following describes an embodiment of the present invention with reference to the drawings.

(First embodiment)
First, the configuration of a filter housing according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view of the filter housing of this embodiment.

The filter housing 10 is a cylindrical metallic container that houses multiple elongated cylindrical filter cartridges (not shown) therein, and has an upper housing 1 and a lower housing 2. The upper housing 1 is formed in a cylindrical shape with an open lower end, and has a ferrule portion 11 on the periphery of the opening. The ferrule portion 11 is joined by welding to an upper body 12 of the upper housing 1, which will be described later. The lower housing 2 is formed in a cylindrical shape with an open upper end, and has a ferrule portion 21 on the periphery of the opening. The ferrule portion 21 is joined by welding to a lower body 22 of the lower housing 2, which will be described later. The upper housing 1 and the lower housing 2 are detachably fixed to each other by tightening the ferrule portions 11 and 21, which sandwich an O-ring (not shown), with a clamp band 3. The metal material constituting the filter housing 10 is not particularly limited, but stainless steel is preferably used from the viewpoint of pressure resistance and mechanical strength.

The upper housing 1 is composed of a cylindrical upper body 12 with both ends open, and a hemispherical upper mirror plate 13. The upper mirror plate 13 is welded to the upper body 12 so as to close the opening at the top end of the upper body 12. In addition, handles 14 are attached to both sides of the upper housing 1 for grasping and moving the upper housing 1 when it is released from its fixation to the lower housing 2.

The lower housing 2 is composed of a cylindrical lower body 22 with both ends open, a hemispherical lower end plate 23, and a disk-shaped mesh plate 24. The mesh plate 24 is welded between the lower body 22 and the lower end plate 23 so as to close the opening at the lower end of the lower body 22 and the opening of the lower end plate 23, in other words, so that its peripheral portion forms part of the side wall of the lower housing 2. As a result, the inside of the filter housing 10 is divided into an upper space 4 that contains a filter cartridge and into which the liquid to be treated flows, and a lower space 5 into which the treated liquid filtered by the filter cartridge flows. In addition, an inlet pipe 25 that communicates with the upper space 4 and supplies the liquid to be treated to the upper space 4 is attached to the side of the lower housing 2, and an outlet pipe 26 that communicates with the lower space 5 and discharges the treated liquid to the outside is attached to the lower part of the lower housing 2.

In this embodiment, laser welding is used to weld the mesh plate 24 to the lower body 22, and also to weld the mesh plate 24 to the lower end plate 23. Below, this welding method, which is part of the manufacturing method for the filter housing of this embodiment, is described with reference to FIG. 2. FIGS. 2(a) to 2(d) are cross-sectional views showing the steps of the welding method for the mesh plate of this embodiment, and are enlarged views corresponding to the area surrounded by circle A in FIG. 1.

First, as shown in FIG. 2(a), a disk member 30 that will become the mesh plate 24 is prepared. Specifically, a disk member 30 having the same diameter as the lower body 22 and the lower end plate 23 is prepared. The thickness of the disk member 30 is not particularly limited, so long as it has a thickness that can withstand the pressure difference between the primary side and the secondary side (the pressure difference between the upper space 4 and the lower space 5) acting on the filter cartridge when it becomes the mesh plate 24 and is installed in the filter housing 10, and a thickness that is the sum of the heights of the ribs 33 and 34 described below.

Next, a plurality of through holes (not shown) for supporting the filter cartridge are formed in the disk member 30. Then, as shown in FIG. 2B, annular ribs 33 and 34 protruding in the axial direction are formed on the peripheral portions of both faces 31 and 32 of the disk member 30. Specifically, a circular recess 35 is formed in the area of the upper surface 31 of the disk member 30, excluding the peripheral portion having the same width as the thickness of the lower body 22. As a result, an upper surface rib 33 having the same thickness as the thickness of the lower body 22 is formed along the peripheral portion of the upper surface 31 of the disk member 30. In addition, a circular recess 36 is also formed in the area of the lower surface 32 of the disk member 30, excluding the peripheral portion having the same width as the thickness of the lower mirror plate 23. As a result, a lower surface rib 34 having the same thickness as the thickness of the lower mirror plate 23 is formed along the peripheral portion of the lower surface 32 of the disk member 30. In this way, the mesh plate 24 is completed.

Next, as shown in FIG. 2(c), the lower end 22a (the end forming the lower opening) of the lower body 22 is butted against the tip 33a of the upper surface rib 33 of the batten 24, and the butted parts 22a, 33a are joined by laser welding. Specifically, a laser beam is irradiated from the outer periphery of the butted parts 22a, 33a to melt and integrate the parts. In this way, as shown in FIG. 2(d), a welded part 27 is formed between the lower body 22 and the upper surface rib 33 of the batten 24, where the two are joined by laser welding.

Similarly, as shown in FIG. 2(c), the upper end portion (the end portion forming the opening) 23a of the lower end plate 23 is butted against the tip portion 34a of the lower surface rib 34 of the batten 24, and the butted portions 23a, 34a are joined by laser welding. Specifically, a laser beam is irradiated from the outer periphery of the butted portions 23a, 34a, melting and integrating the portions. Thus, as shown in FIG. 2(d), a welded portion 28 is formed between the lower end plate 23 and the lower surface rib 34 of the batten 24, where the two are joined by laser welding.

In this way, in this embodiment, by forming an annular upper surface rib 33 on the mesh plate 24, it becomes possible to use butt welding by laser welding for welding to the lower body 22. Similarly, by forming an annular lower surface rib 34 on the mesh plate 24, it becomes possible to use butt welding by laser welding for welding to the lower end plate 23. Laser welding is a welding method that has a higher energy density than, for example, TIG welding, and can perform welding while penetrating the laser beam from the front side to the back side of the base material. Therefore, in this embodiment, it is possible to perform back-strip welding in which weld beads 27a, 28a are formed on the inner periphery of the welded parts 27, 28 in one welding, which could not be achieved with conventional TIG welding, and therefore welding work from the back side (inner periphery side) is not necessary. As a result, a sufficient amount of penetration can be ensured even with a smaller amount of heat input, and good welded parts 27, 28 with suppressed sensitization can be formed.

There is no particular restriction on the type of laser used for the above-mentioned laser welding, but it is preferable to use a fiber laser, since it has a high degree of freedom in the irradiation position and irradiation angle, and the laser beam can be irradiated at an appropriate position and angle. In addition to laser welding, electron beam welding can also be considered as a welding method with high energy density (i.e., high-energy beam welding method). However, it is preferable to use laser welding, since it is cost-effective because welding can be performed in the atmosphere, and it is also suitable for welding relatively large components such as the filter housing of this embodiment.

In this embodiment, in addition to welding the mesh plate 24 to the bodies 22 and 23, it is preferable to use laser welding also for welding the ferrule portion 11 to the upper body 12, welding the ferrule portion 21 to the lower body 22, and welding the upper body 12 to the upper head plate 13. This allows the same welding equipment to be used for these welds, which results in more efficient manufacturing processes and reduced costs.

Second Embodiment
The configuration of a filter housing according to a second embodiment of the present invention will be described with reference to Fig. 3. Fig. 3 is a schematic enlarged cross-sectional view of the filter housing of this embodiment, and corresponds to Fig. 2.

To realize butt welding by laser welding with the lower body 22 and the lower end plate 23, it is sufficient that the peripheral portion of the mesh plate 24 protrudes in the axial direction (up and down direction) at least more than the area adjacent to the inner circumference side. Therefore, in the first embodiment, the circular recesses 35, 36 are formed by cutting all areas of both sides 31, 32 of the disc member 30 except for the peripheral portion to form the annular ribs 33, 34 on the mesh plate 24, but the method of forming the ribs 33, 34 is not limited to this. For example, as in this embodiment, the annular ribs 33, 34 may be formed on the mesh plate 24 by forming grooves 37, 38 that are cut in an annular shape only in the area on the inner circumference side from the peripheral portion. As a result, in this embodiment, not only is the amount of cutting less than in the first embodiment in which all areas of both sides 31, 32 of the disc member 30 except for the peripheral portion are cut, but the thickness of the disc member 30 itself can be made thinner, thereby reducing manufacturing costs. The width of the grooves 37 and 38 may be any width as long as the laser beam does not affect the area of the plate 24 that is more inward than the grooves 37 and 38. The other configurations and manufacturing method (welding method) of this embodiment are the same as those of the first embodiment, and the effects obtained thereby are also the same as those of the first embodiment.

REFERENCE SIGNS LIST 1 Upper housing 2 Lower housing 3 Clamp band 4 Upper space 5 Lower space 10 Filter housing 11, 21 Ferrule part 12 Upper body 13 Upper end plate 14 Handle 22 Lower body (first housing member)
22a Lower end portion 23 Lower end plate (first housing member)
23a Upper end portion 24 Mesh plate (second housing member)
25 Inlet pipe 26 Outlet pipe 27, 28 Welded portion 27a, 28a Weld bead 30 Disk member 31 Upper surface 32 Lower surface 33 Upper surface rib 34 Lower surface rib 33a, 34a Tip portion 35, 36 Recess 37, 38 Groove

Claims (8)

A method for manufacturing a metal filter housing having a cylindrical or semispherical first housing member and a disk-shaped second housing member that closes an opening of the first housing member, comprising the steps of:
forming an annular rib on a peripheral portion of a surface of the second housing member, the rib protruding in an axial direction beyond at least an area adjacent to the inner peripheral side;
a step of butting an end portion of the first housing member that forms the opening with a tip portion of the rib and joining the butted portion by laser welding ;
A method for manufacturing a filter housing, wherein the step of forming the rib includes forming an annular groove in an area of the surface of the second housing member that is more inward than the peripheral edge portion, thereby forming the rib along the peripheral edge portion . A method for manufacturing a metal filter housing having a cylindrical or semispherical first housing member and a disk-shaped second housing member that closes an opening of the first housing member, comprising the steps of:
providing the second housing member having a diameter the same as a diameter of the first housing member ;
forming an annular rib on a peripheral portion of a surface of the second housing member, the rib protruding in an axial direction beyond at least an area adjacent to the inner peripheral side and having the same thickness as the first housing member ;
a step of butting an end portion of the first housing member that forms the opening with a tip portion of the rib, and joining the butted portion by laser welding . 3. The method for manufacturing a filter housing according to claim 2, wherein the step of forming the rib includes forming an annular groove in an area of the surface of the second housing member that is more inward than the peripheral edge portion, thereby forming the rib along the peripheral edge portion. 3. The method of claim 2, wherein the step of forming the rib includes forming a circular recess in an area of the surface of the second housing member excluding the peripheral edge portion, thereby forming the rib along the peripheral edge portion. The method for manufacturing a filter housing according to any one of claims 1 to 4, wherein the step of joining the butted parts includes irradiating the butted parts with a laser beam from the outer periphery of the butted parts to form a weld bead on the inner periphery of the butted parts. The method for manufacturing a filter housing according to any one of claims 1 to 5, wherein the metal is stainless steel. A metal filter housing having a cylindrical or semispherical first housing member and a disk-shaped second housing member closing an opening of the first housing member,
the second housing member has an annular rib formed on a peripheral portion of a surface of the second housing member and protruding in an axial direction beyond at least an area adjacent to the inner peripheral side,
the rib is defined by an annular rib formed in a region of the surface of the second housing member that is radially inward relative to a peripheral edge portion,
A filter housing, wherein the first housing member and the second housing member are joined by laser welding such that an end portion of the first housing member that forms the opening and a tip portion of the rib are butted together. A metal filter housing having a cylindrical or semispherical first housing member and a disk-shaped second housing member closing an opening of the first housing member,
the first housing member and the second housing member have the same diameter;
the second housing member has an annular rib formed on a peripheral portion of a surface of the second housing member, protruding in an axial direction beyond at least an area adjacent to the inner peripheral side, and having the same thickness as the first housing member;
A filter housing, wherein the first housing member and the second housing member are joined by laser welding such that an end portion of the first housing member that forms the opening and a tip portion of the rib are butted together.

Images