JP2017047445A - Metallic porous body, metallic filter and manufacturing method of metallic porous body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic porous body which returns to an original shape after deformation due to an external force in the metallic porous body manufactured by winding a metal wire spirally and in a multilayer shape, and to spread usage and application of the metallic porous body.SOLUTION: A hollow cylindrical body made by winding stainless metal wiring spirally and in a multi-layer shape such that inclination angles of respective metallic wires 20A, 20B which constitute wire layers L1, L2 adjacent to each other are differentiated from each other is manufactured and heat treatment for four hours in the range of 600 to 700°C is executed for the manufactured hollow cylindrical body. An obtained metallic porous body can be extended and contracted in the axial direction and can be curved and deformed by receiving an external force and is returned to the original shape by removing the external force.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a porous metal body produced by winding a metal wire in a spiral shape and a multilayer shape, and in particular, it can be freely deformed from an initial shape by applying an external force, and the external force can be removed. The present invention relates to a porous metal body having a self-restoring property that returns to its original form.

Conventionally, a cylindrical metal porous body produced by winding a metal wire in a spiral shape and a multilayer shape is known.
Patent Document 1 describes an inflator filter used for an automobile airbag. In this filter, one metal wire is wound around a mandrel, formed into a cylindrical shape, and then subjected to a sintering process to join adjacent metal wires. For this reason, this filter has high rigidity, and has a characteristic that the overall shape and opening can be maintained even by the impact of high-temperature gas generated by explosive combustion of the gas generating agent.
Patent Document 2 describes a metal porous body that does not kink even when deformed by human hands. “Kink” refers to a phenomenon in which when an external force is applied to the metal porous body, the metal porous body is crushed and does not recover to its original shape even if the external force is removed. This metal porous body can also be obtained by winding a single metal wire around a mandrel and forming it into a cylindrical shape, followed by a sintering treatment.

JP 2001-171472 A JP 2014-140892 A

The metal porous bodies described in Patent Documents 1 and 2 are subjected to sintering treatment, and adjacent metal wires are joined to each other. In particular, in Patent Document 1, since a sintering process is performed in order to obtain a high-rigidity filter, it is not planned to be used after being deformed.
Moreover, in the metal porous body described in Patent Document 2, it is possible to bend and deform freely by human hands, but since the metal wires are joined together, after the external force is removed, the metal porous body is also deformed. It is assumed that it is used in a state in which the shape is maintained. Therefore, after the external force is removed, it does not return to its original shape by itself.
A metal porous body formed by winding a metal wire in a spiral and multi-layer shape has not been proposed so far and can be restored to its original shape after deformation, and such a metal porous body has been developed. If so, there is a possibility that the usage and application of the metal porous body will be expanded.
The present invention has been made in view of the above circumstances, and in a metal porous body produced by winding a metal wire in a spiral shape and a multilayer shape, it is a novel material that returns (restores) to its original shape by itself after deformation. An object of the present invention is to provide a porous metal body.

In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that the metal wire is wound in a spiral shape and a multilayer shape so that the inclination angles of the metal wire materials constituting the adjacent wire material layers are different. A hollow cylindrical metal porous body, wherein the metal porous body is deformed when an external force is applied and returns to the original shape when the external force is removed.
The invention according to claim 2 is characterized in that the metal porous body is deformed in the axial direction by applying the external force in the axial direction, and returns to the original shape by removing the external force. .
The invention according to claim 3 is characterized in that the metallic porous body is bent and deformed by applying the external force, and is restored to the original shape by removing the external force.

The invention according to claim 4 is characterized in that the metallic porous body has an original shape in a cylindrical shape in which an axis extends linearly.
According to a fifth aspect of the present invention, at least a part of a hollow cylindrical body in which the metal wire is wound spirally and in a multilayer shape so that the inclination angles of the metal wires constituting the adjacent wire layers are different. A stress-relieving annealing treatment is applied to the above.
The invention according to claim 6 is characterized by a metal filter including the metal porous body according to any one of claims 1 to 5.

The invention according to claim 7 is a method for producing a metal porous body, wherein the metal wire is wound in a spiral shape and in a multilayer shape so that the inclination angles of the metal wire members constituting the adjacent wire layer are different. And a step of producing a porous hollow cylindrical body, and a heat treatment step of performing stress-relieving annealing on at least a part of the hollow cylindrical body.
The invention according to claim 8 is a method for producing a metal porous body, wherein the metal wire is stainless steel, and a treatment temperature in the heat treatment step is 600 ° C to 700 ° C.

  ADVANTAGE OF THE INVENTION According to this invention, although it deform | transforms when external force is applied, it can provide the novel metal porous body which returns to an original form by removing external force, The usage and use of a metal porous body expand. .

It is a top view of the metal porous body concerning a first embodiment of the present invention. It is a partial expansion perspective view of the metal porous body concerning a first embodiment of the present invention. It is a perspective view which shows the state which curved the metal porous body. It is the flowchart which showed the manufacturing process of the metal porous body. It is a schematic diagram which shows an example of the manufacturing apparatus of a metal porous body. (A)-(c) is a top view of the metal porous body which concerns on 2nd embodiment of this invention. It is a figure which shows the material of a test body, a shape, heat processing conditions, and an expansion-contraction evaluation test result with a table | surface. (A), (b) is a figure shown with the enlarged photograph of the surface of a test body, (a) shows an initial state, (b) is a figure which shows the state at the time of expansion | extension. It is a figure which shows the principle of a bubble point test.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .

Hereinafter, embodiments of the present invention will be described in detail.
[First embodiment]
The metal porous body according to the first embodiment of the present invention will be described. FIG. 1 is a plan view of a metal porous body according to the first embodiment of the present invention. FIG. 2 is a partially enlarged perspective view of the metal porous body according to the first embodiment of the present invention. FIG. 3 is a perspective view showing a state in which the metal porous body is curved. FIG. 1 shows a state in which the metal porous body is in its original form (initial shape).
The metal porous body according to the present embodiment has stretchability and flexibility, deforms when external force is applied, and returns to the original shape (or original posture) when the external force is removed (restored to the original shape). It is characterized by having elasticity.

As shown in FIG. 2, the metal porous body 10 includes a single metal wire 20 in a spiral shape so that the inclination angles of the metal wire materials 20A and 20B constituting the adjacent wire material layers Ln and Ln-1 are different from each other. It is a hollow cylindrical shape formed by winding in multiple layers.
As shown in FIG. 1, when the metal porous body 10 is in the initial shape, the axis X extends linearly and is contracted in the axial direction.
The metallic porous body 10 can be expanded and contracted in the axial direction. When an external force in the direction along the axial direction is applied to the metallic porous body 10 in the initial shape, the metallic porous body 10 expands and contracts in the axial direction. . Further, by removing the external force, the metal porous body 10 has a property of self-restoring to the initial shape.
Further, the metal porous body 10 has flexibility (or flexibility), and when an external force that curves the axis X is applied to the metal porous body 10 in the initial shape shown in FIG. The body 10 is curved without kinking as shown in FIG. Further, by removing the external force, the metal porous body 10 has a property of self-restoring to the initial shape. Here, “kink” means that when an external force for bending the metal porous body 10 is applied to the metal porous body 10, the metal porous body 10 is crushed and the external force is removed from the metal porous body. A phenomenon that does not return to its original form.

Hereinafter, a detailed configuration of the metal porous body will be described.
<Shape of metal porous body>
As shown in FIG. 2, the hollow cylindrical metal porous body 10 according to the embodiment of the present invention has at least one metal wire 20 having a constant inclination angle with respect to the axial direction (vertical direction in the figure). It is formed by having a spiral shape and winding it in multiple layers. Here, the individual layers wound in the same direction are referred to as wire layers L1, L2, L3. The metal wire which comprises each wire layer L1, L2, L3 ... is extended in the same direction inclined with respect to the axial direction of the metal porous body 10 by front view, and comprises each adjacent wire layer The metal wires extend in directions intersecting each other (not parallel).

The extending direction of the wire rod 20A (thickness is not shown) constituting the outermost wire rod layer Ln in FIG. 1 is the direction indicated by the solid line arrow, and the wire rod 20B constituting the wire rod layer Ln-1 immediately inside thereof extends. The direction is the direction indicated by the dashed arrow.
That is, the metal porous body 10 includes one wire layer (for example, a wire layer L1) formed by spirally winding the metal wire 20 at a certain inclination angle with respect to the axial direction, and one wire layer L1. The other wire rod layer (for example, the wire rod layer L2) formed by winding the metal wire spirally at an inclination angle different from that of the metal wire rod constituting the one wire rod layer L1. And having. The metal wires constituting each of the one wire layer L1 and the other wire layer L2 adjacent thereto are not parallel to the axial direction and are configured to intersect each other.
In addition, you may comprise so that the inclination | tilt angle with respect to the axial direction of the metal wire which comprises a wire layer may change in one wire rod layer.

When the metal porous body 10 is used as a filter, it removes unnecessary substances from various fluids such as liquid and gas, and at the same time, cools the fluid passing through the metal porous body. The size (axial dimension, diameter, thickness, etc.) of the metal porous body is appropriately determined according to the structure and size of the apparatus equipped with the metal porous body.
Examples of the metal used as the material of the metal porous body include iron, mild steel, stainless steel, nickel alloy, copper alloy, and austenitic stainless steel (SUS304, SUS316, SUS316L, etc.) is preferable. is there.
Moreover, the thickness and cross-sectional shape of the metal wire used for the metal porous body are appropriately determined according to the size of the metal porous body, the material removed by the metal porous body, the pressure loss, and the like.
As the metal porous body, for example, in addition to a metal wire having a perfectly circular cross section, a flat rolled wire obtained by rolling a metal wire, or the like that has been rolled to have a predetermined cross-sectional shape is used.

<Manufacturing process>
The manufacturing process of the metal porous body will be described. FIG. 4 is a flowchart showing a manufacturing process of a metal porous body.
The metal porous body 10 includes a wind process (step S1), a die cutting process (step S2), a heat treatment process (step S3), a metal fitting installation process (step S4), a cleaning process (step S5), and an inspection process (step S6). ).
In addition, step S1 and S2 are processes which form the hollow cylindrical body used as the origin of metal porous bodies.
Moreover, the die-cutting process of step S2 and the heat treatment process of step S3 can be performed interchangeably. In addition, after the die cutting process in step S2, the heat treatment process in step S3 may be performed after the metal fitting attaching process shown in step S4.

<< Wind process, die cutting process >>
FIG. 5 is a schematic diagram illustrating an example of a metal porous body manufacturing apparatus. This apparatus is for producing a hollow cylindrical body that is a base of a metal porous body from a metal strand. Moreover, the shape of the produced hollow cylindrical body becomes the initial shape of the metal porous body.
The manufacturing apparatus 100A is longer than a rolling apparatus 110 that rolls a metal strand 21 supplied from a bobbin (not shown) and a metal strand (hereinafter referred to as “metal wire 20”) whose cross-sectional shape is deformed by rolling. A tension unit 120 that applies a predetermined tension in the direction and a winding device 130 that winds the metal wire 20 around a mandrel 131 to form a hollow cylindrical body are roughly provided. A plurality of transport rollers 140 that transport the metal wire while guiding the metal wire are arranged on the transport path of the metal wire 20.
The rolling device 110 includes two cylindrical rolling rollers 111a and 111b that are arranged to face each other and rotate. A portion where the surfaces (opposing surfaces) of the rolling roller 111a and the rolling roller 111b are in contact with each other constitutes a pressing unit 112 that is deformed into a desired shape with the metal strand 21 interposed therebetween. The rolling device 110 obtains the metal wire 20 having a predetermined cross-sectional shape by plastically deforming the metal wire 21 with the pressurizing unit 112 under a predetermined temperature and pressure. The rolling may be cold rolling or hot rolling.

The tension unit 120 includes a fixed roller 121 that is fixedly arranged in a rotatable state at a predetermined position, and a movable roller 122 that moves toward or away from the fixed roller 121 and that is rotatable. By moving the movable roller 122 closer to or away from the fixed roller 121, a predetermined tension is applied to the metal wire 20 that is wound around the fixed roller 121 and the movable roller 122 and conveyed.
The winding device 130 includes a mandrel 131 that rotates in a predetermined direction at a predetermined speed, and a guide member that guides the metal wire 20 by reciprocating at a predetermined speed in the axial direction of the mandrel 131 (direction orthogonal to the paper surface in the drawing). 132. The mandrel 131 is generally columnar or cylindrical, and is generally formed from a metal such as stainless steel, a copper alloy, or an aluminum alloy.

In order to produce a hollow cylindrical body, one end of the metal wire 20 is locked at an appropriate position of the mandrel 131, and the mandrel 131 is fixed in a state where a predetermined tension is applied to the metal wire 20 by the tension unit 120. And the metal wire 20 is reciprocated in the axial direction of the mandrel 131 by the guide member 132. By this operation, the metal wire 20 is wound around the outer periphery of the mandrel 131 in a spiral shape and a multilayer shape. Moreover, the metal wire which comprises an adjacent wire layer cross | intersects each other, and forms a mesh | network.
For example, in the first metal wire layer wound directly around the outer periphery of the mandrel 131, if each wire is inclined clockwise by a predetermined angle θ with respect to the axial direction of the mandrel in FIG. The wire constituting the second metal wire layer wound around the outer periphery of the wire layer is inclined counterclockwise by a predetermined angle θ with respect to the axial direction of the mandrel.

After winding the metal wire 20 a predetermined number of times (a predetermined number of layers), the metal wire 20 is cut, and the cut end portion is joined to an appropriate position of the wire that has been wound by spot welding or the like and removed from the mandrel 131. Thus, a hollow cylindrical body is obtained (step S2: die cutting step).
The angle (winding angle) of the metal wire 20 with respect to the axial direction of the mandrel 131 and the interval (pitch) between the metal wires 20 adjacent in the axial direction are the ratio between the rotational speed of the mandrel 131 and the moving speed of the guide member 132. It can be changed by adjusting appropriately. By appropriately changing the thickness, winding angle, pitch, and number of windings of the metal wire, the pressure loss of the fluid passing through the metal porous body is controlled to an appropriate value when the metal porous body is used as a filter. can do.

<< Heat treatment process >>
In the heat treatment step, stress-relieving annealing (low-temperature annealing) is performed to reduce or remove the residual stress of the metal wire generated during rolling or winding. The metal porous body obtained through this heat treatment step has elasticity, and can be freely expanded and contracted or deformed by applying an external force. However, when the external force is removed, the metal porous body exhibits a self-restoring ability to return to the initial shape.
In the heat treatment step, the hollow cylindrical body is placed in a heating furnace and maintained at a predetermined temperature for a predetermined time, and then the hollow cylindrical body is cooled. The heat treatment is carried out for about several hours (for example, about 4 hours) in a furnace set at a treatment temperature of 600 ° C. to 700 ° C., preferably 600 ° C.
The heat treatment can be performed in air, but is preferably performed in a vacuum, a reducing gas that reduces oxides on the surface, or an inert gas that does not cause the metal wire to become brittle or cause a chemical reaction. . Examples of the reducing gas include hydrogen gas, a mixed gas of hydrogen and nitrogen, and an ammonia decomposition gas. Examples of the inert gas include nitrogen gas and argon.

<< Mounting, cleaning and inspection process >>
A metal fitting is attached to the metal porous body 10 in order to facilitate handling of the metal porous body obtained through the heat treatment step. In this example, the end fitting 13 is attached to the axial end by welding. The end fitting 13 can be a cylindrical member having a hole communicating with the inside of the hollow portion of the metal porous body 10. The end fitting 13 shown in FIG. 1 has a flange portion that projects stepwise from the surface of the metal porous body 10 in the outer diameter direction.
The metal porous body 10 manufactured as described above is cleaned and completed through a predetermined inspection.

<Effect>
The metal porous body is a porous body having a plurality of fine pores. The metal porous body expands in the axial direction, and the pore diameter (opening) expands. When the metal porous body contracts, the pore diameter decreases, so use it as a metal filter whose filtration accuracy can be adjusted as necessary. (See FIGS. 8A and 8B).
In addition, the metal porous body can be used as a flexible metal filter because foreign substances can be removed in a state of being appropriately curved and deformed with a desired curvature as shown in FIG. When the metal porous body is used as a flexible metal filter, it can be used as a static filter that removes foreign matters while keeping the curved and deformed shape fixed. Further, by connecting two rotating members whose axial directions are not linear with a metallic porous body, the metallic porous body can be used as a dynamic filter for performing filtration while rotating.
Since the metal porous body is freely curved and deformed, it is used as a power transmission member that transmits the rotational force output from one of the two rotating members whose axial directions are not linear to the other rotating member at a constant speed. It is also possible.

Since the metal wires constituting the metal porous body are not joined to each other, when the metal porous body is deformed, the metal wires displace each other's positional relationship. Since the metal porous body has elasticity and self-restoring force, when the metal porous body is deformed, the positional relationship between the metal wires is displaced substantially evenly (see FIG. 8B). Therefore, when it is expanded and contracted in the axial direction, the openings are expanded and contracted substantially uniformly. Moreover, when it carries out curve deformation, according to the curvature of each part of a metal porous body, the position of metal wire materials displaces substantially equally. Accordingly, there is no occurrence of an extremely large difference in opening at a specific location due to deformation.
From the above, in a state where the metal porous body obtained by the present invention is deformed into a desired stretch amount and a desired curved shape, the sintering treatment is carried out while maintaining the shape, thereby allowing any arbitrary It is possible to produce a hollow cylindrical metal filter deformed into a shape.

The initial shape of the metal porous body is determined by the form of the hollow cylindrical body obtained in the winding process. In this example, a metal porous body is produced from a cylindrical hollow cylinder produced by winding a metal wire around a cylindrical or columnar mandrel whose axis extends linearly. Therefore, a metal porous body having a cylindrical initial shape having a linearly extending axis X can be produced by a relatively simple manufacturing method.
As described above, the present invention has been described based on the example of the cylindrical metal porous body having both ends in the axial direction opened. However, the metal porous body may have a cylindrical shape in which one end in the axial direction is closed. Further, depending on the shape of the mandrel around which the metal wire is wound, it is possible to produce a metal porous body having a rectangular tube shape, a conical shape, a pyramid shape, or other shapes.
Moreover, although the expansion and contraction and the curvature are exemplified as the deformed shape, the deformed shape includes various deformations such as bending and twisting.

[Second Embodiment]
A second embodiment of the present invention will be described. The second embodiment is characterized in that the metal porous body partially includes a non-restorable portion that does not have self-restoration.
FIGS. 6A to 6C are plan views of a metal porous body according to the second embodiment of the present invention.
The metal porous body 30 includes a recoverable portion 31 and a non-restorable portion 33.
The recoverable portion 31 is a portion having the property of the metal porous body shown in the first embodiment. The recoverable portion 31 can expand and contract in the axial direction and can bend the axis X freely. This is a part that can be restored.
The non-restorable portion 33 is a portion that can be expanded and contracted or curved, but cannot be restored by its own force after deformation, or cannot be deformed even when an external force is applied.

A metal porous body 30 </ b> A shown in FIG. 6A is an example having recoverable portions 31 and nonrecoverable portions 33 that are alternately arranged in the axial direction.
Moreover, the porous metal body 30B shown in FIG. 6B is an example in which the non-restorable portion 33 extending in the axial direction is arranged in a part of the circumferential direction, and the rest of the circumferential direction is the restorable portion 31.
FIG. 6C shows an example in which the non-restorable portion 33 is arranged in a spiral shape with respect to the metal porous body 30 </ b> C and the other portion is the restorable portion 31.

The non-restorable portion 33 can be produced by partially performing heat treatment under conditions that make it impossible to restore the initial shape after deformation by external force, or heat treatment under conditions that make it impossible to deform even by external force. It is. For example, the recoverable portion 31 and the non-restorable portion 33 are mixed by performing a partial heat treatment (including a sintering process) using a high frequency, a light beam, or an electron beam, or a partial welding process. The metal porous body 30 can be produced.
By mixing the recoverable portion 31 and the non-restorable portion 33, the metal porous body 30 is deformed while the positions of the metal wires constituting the metal porous body 30 are displaced substantially evenly, and the deformed shape is also obtained. Can be held.

〔Evaluation test〕
A plurality of metallic porous bodies having different temperature conditions during the heat treatment were produced and evaluated. FIG. 7 is a table showing the test specimen material, shape, heat treatment conditions, and expansion / contraction evaluation test results. 8 (a) and 8 (b) are diagrams showing enlarged photographs of the surface of the specimen, (a) showing an initial state, and (b) showing a state at the time of extension.

<Preparation of specimen>
The metal porous body which is a test body was produced as follows.
First, an austenitic stainless steel SUS316L and a round wire having a wire diameter of 0.13 mm were formed into a flat rolled wire having a thickness of 0.065 mm by cold rolling. Next, a flat rolled wire is wound around a cylindrical mandrel having an outer diameter of 3.7 mm in a spiral and multilayer manner so that adjacent wires intersect each other, and then the mandrel is pulled out to form a cylindrical hollow cylindrical body. Was made.
The dimensions of this hollow cylindrical body are an inner diameter of 3.7 mm, an outer diameter of 6.2 mm, and a total length of 100 mm. The interval between adjacent metal wires is approximately 630 μm, and the angle between intersecting metal wires is approximately 46 degrees (see FIG. 8A). Although this hollow cylindrical body can be expanded and contracted in the axial direction by applying an external force, it does not have self-restoration, and once deformed, it remains in its deformed shape.

This hollow cylindrical body was heat-treated by changing only the temperature condition in the range of 400 to 1250 degrees. Regarding the heat treatment conditions, common matters other than temperature are as follows. The heat treatment was performed in a non-oxidizing H2 atmosphere. The inside of the heat treatment furnace was heated from normal temperature (range of 15 to 25 degrees) to the target temperature at a rate of 13 ° C./min, and the target temperature was maintained for 4 hours. Thereafter, the specimen was taken out of the heat treatment furnace and rapidly cooled (taken out in a normal temperature atmosphere and naturally cooled).
For the test bodies 1 to 6, heat treatment at a temperature of 400 to 900 ° C. was performed at 100 ° C. intervals. Moreover, about the test body 7, heat processing was implemented at the temperature of 1250 degreeC.
After heat treatment, end metal fittings having flange portions larger in diameter than the test specimens were attached to both ends in the axial direction of the test specimens by welding and cleaned to complete the test specimens. The end fitting was attached so that the axial end edge of the metal porous body was exposed.

<Extension evaluation test>
A change when the test bodies 1 to 7 are extended will be described. The expansion / contraction evaluation test was conducted from the viewpoint of whether the specimen is stretched in the axial direction (stretched or not), how much stretched, or returned to the shape before stretching (presence of self-restoration). .
Specimen 1-2 was movable and expanded at a maximum of 24.5 mm and 37.0 mm, respectively, but remained stretched even when the tensile force was removed, and did not have self-restoration.
Specimen 3 extended a maximum of 23.8 mm. After stretching, when the tensile force was removed, it returned to the state before stretching.
The test body 4 extended | stretched 12.5 mm at maximum. After stretching, when the tensile force was removed, it returned to the state before stretching. However, compared with the test body 3, the extension amount was about half, and the movable range was narrow.
In the test body 5-7, the metal wires were sintered and did not have mobility.
From the above, it has been found that the heat treatment conditions are preferably 600 ° C. to 700 ° C., preferably 600 ° C.

<Bubble point test>
About the test body 3, the bubble point test based on ASTM-E-128-61 was implemented, and the filtration precision in the case of using a metal porous body as a filter was measured.
FIG. 9 is a diagram showing the principle of the bubble point test.
In the bubble point test, the test filter is submerged in isopropyl alcohol, and the internal pressure of the filter is gradually increased from zero. Then, bubbles are first generated from the largest hole (initial point). The maximum hole diameter can be obtained from the internal pressure at this time. The pore diameter D [μm] is obtained by the following equation (1).

D = 4S · cos θ / (P−γh) (1)
However,
D: Pore diameter S: Interfacial tension of isopropyl alcohol θ: Paint angle P: Internal pressure γ: Density of isopropyl alcohol h: Liquid depth.

However, in actuality, compared with the glass bead method, the pore diameter D [μm] is
D [μm] = 3700 / P [mmH ₂ O] (2)
Is required. The numerical value 3700 is a constant.

  When the internal pressure is further increased, the flow rate of air changes. However, when the relationship between the internal pressure and the flow rate is shown in the graph, the internal pressure when a state called a burst point that uniformly foams from the entire surface of the test filter is obtained. The average pore diameter of the filter can be obtained from this internal pressure.

The average pore diameter before and after the expansion and contraction of the test body 3 was determined by the bubble point test. In this test, an air supply tube is connected to the end fitting 13 shown in FIG. 1, and a portion of the metal porous body 10 located between the end fittings 13 and 13 (in FIG. In the portion shown), the extension amount and the average pore diameter were measured.
Here, FIG. 8A is an enlarged photograph of the surface of the specimen before stretching (initial state), and FIG. 8B is an enlarged photograph of the surface of the specimen when stretched.
The length between the end fittings of the test body before stretching (initial state) was 88 mm, and the average pore diameter at this time was 28 [μm]. Moreover, as shown to Fig.8 (a), the space | interval between adjacent metal wires is about 630 micrometers, and the angle between the intersecting metal wires is about 46 degrees.
When the specimen was stretched and fixed with a jig so that the length between the end fittings was 98 mm (elongation rate 111.4%), and a bubble point test was performed, the average hole diameter was 33. [Μm]. At this time, as shown in FIG. 8B, the interval between the adjacent metal wires was approximately 792 μm, and the angle between the intersecting metal wires was approximately 59 degrees.

As described above, the pore diameter is expanded by extending the metal porous body obtained by the present invention in the axial direction and changing the angle between the intersecting metal wires. It should be noted that the amount of expansion and the hole diameter are in a monotonically increasing relationship within the extendable range.
When the metal porous body according to the present invention is used as a filter, it can be used as a filter having a desired filtration accuracy (pore diameter) by appropriately stretching the metal porous body in the axial direction. Also, more effective backwashing can be performed by extending the metal porous body and performing backwashing rather than during filtration.
In addition, in the case of a rectangular cylindrical metal porous body, a metallic porous body closed at one end in the axial direction, and a conical metal porous body, the diameter of the pores can be increased or decreased by changing the angle between the metal wires. Can do.

[Summary of Embodiment, Action, and Effect of the Present Invention]
<First embodiment>
This embodiment is a hollow cylindrical metal porous structure in which the metal wire 20 is spirally wound in multiple layers so that the inclination angles of the metal wires 20A and 20B constituting the adjacent wire layers L1 and L2 are different. The body 10 is characterized in that the metal porous body is deformed when an external force is applied and returns to the original shape when the external force is removed.
The metal porous body according to this aspect is deformed by applying an external force, but returns to its original shape by removing the external force, so that the metal porous body can be used in a new usage and application different from the conventional one.
In addition, the deformation | transformation here includes various deformation | transformation, such as expansion / contraction, a curve, a bending | flexion, and a twist.

<Second embodiment>
The metallic porous body according to this aspect is characterized in that it is expanded and contracted in the axial direction when an external force is applied in the axial direction, and returns to its original shape when the external force is removed.
The metal porous body according to the present embodiment expands and contracts when an external force is applied in the axial direction, but returns to the original shape when the external force is removed. Can be used for various purposes.

<Third embodiment>
The metallic porous body according to this aspect is characterized in that it is deformed in a curved shape by applying an external force and returns to its original shape by removing the external force.
The metal porous body according to this aspect is bent and deformed by applying an external force that bends the axis X, but returns to its original shape by removing the external force. And can be used in applications.

<Fourth embodiment>
In this aspect, the metal porous body is characterized in that the original shape is a cylindrical shape in which the axis X extends linearly.
The original shape of the metal porous body is determined by the form of the hollow cylindrical body that is the basis of the metal porous body. In this embodiment, a metal porous body is produced from a cylindrical hollow tubular body produced by winding a metal wire around a cylindrical or columnar mandrel whose axis extends linearly. Therefore, the metal porous body according to this embodiment can be produced by a relatively simple method.

<Fifth embodiment>
The metal porous body according to this aspect is a hollow cylinder in which metal wire rods are wound spirally and in a multilayer shape so that the inclination angles of the metal wire rods 20A and 20B constituting the adjacent wire rod layers L1 and L2 are different. Stress-relieving annealing treatment is performed on at least a part of the shaped body.
According to this aspect, the metal porous body obtained by executing the stress removal annealing treatment has elasticity and can be freely expanded and contracted or deformed by applying an external force, but when the external force is removed Expresses the ability to return to its original form.

<Sixth embodiment>
This aspect is a metal filter including the metal porous body according to any one of the first to fifth aspects.
According to this aspect, the usage and application of the metal filter can be expanded by including the metal porous body having a novel property.

<Seventh embodiment>
In the method for manufacturing the metal porous body 10 according to this aspect, the metal wire is spirally wound and multilayered so that the inclination angles of the metal wires 20A and 20B constituting the adjacent wire layers L1 and L2 are different. Including a step of producing a porous hollow cylindrical body (steps S1 and S2) and a heat treatment step of performing stress relief annealing on at least a part of the hollow cylindrical body (step S3). Features.
According to this aspect, it is possible to manufacture a novel metal porous body that is deformed by applying an external force, but returns to its original shape when the external force is removed.

<Eighth embodiment>
In the method for manufacturing the metal porous body 10 according to this aspect, the metal wire is stainless steel, and the treatment temperature in the heat treatment step is 600 ° C to 700 ° C.
According to this aspect, it is possible to manufacture a novel metal porous body that is deformed by applying an external force, but returns to its original shape when the external force is removed.

  L1, L2 ... Wire layer, 10 ... Metal porous body, 13 ... End fitting, 20 ... Metal wire, 21 ... Metal element wire, 30 ... Metal porous body, 31 ... Recoverable part, 33 ... Unrecoverable part, DESCRIPTION OF SYMBOLS 100A ... Manufacturing apparatus, 110 ... Rolling apparatus, 111a ... Rolling roller, 111b ... Rolling roller, 112 ... Pressure part, 120 ... Tension unit, 121 ... Fixed roller, 122 ... Movable roller, 130 ... Winding apparatus, 131 ... Mandrel 132: Guide members, 140: Conveying rollers

Claims (8)

The metal wire is a hollow cylindrical metal porous body wound spirally and in a multilayer manner so that the inclination angle of each metal wire constituting the adjacent wire layer is different,
The metal porous body is deformed when an external force is applied, and returns to its original shape when the external force is removed.   2. The metal porous body according to claim 1, wherein the metal porous body expands and contracts in the axial direction when the external force is applied in the axial direction, and returns to the original shape when the external force is removed. body.   3. The metal porous body according to claim 1, wherein the metal porous body is curved and deformed when the external force is applied, and returns to the original shape when the external force is removed. 4.   The metal porous body according to any one of claims 1 to 3, wherein the metal porous body has a cylindrical shape whose axial line extends linearly.   Stress removal annealing treatment for at least a part of the hollow cylindrical body in which the metal wire is spirally wound in multiple layers so that the inclination angles of the metal wires constituting the adjacent wire layers are different. A metal porous body characterized by that.   A metal filter comprising the metal porous body according to any one of claims 1 to 5. A step of winding the metal wire in a spiral shape and a multilayer shape so that the inclination angle of each metal wire constituting the adjacent wire layer is different, and producing a porous hollow cylindrical body;
And a heat treatment step of performing stress-relieving annealing on at least a part of the hollow cylindrical body.   The said metal wire is stainless steel, The process temperature in the said heat processing process is 600 to 700 degreeC, The manufacturing method of the metal porous body of Claim 7 characterized by the above-mentioned.

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