JPH0434989Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a mesh filter body for filtering molten metal.

(Prior art) A mesh filter that is sewn with fire-resistant fibers such as glass fiber or carbon fiber to give it shape retention properties can remove slag, slag, etc. mixed in non-ferrous metals such as aluminum, and molten metals such as cast iron and cast steel. It has been attracting attention in the casting industry in recent years because of its excellent separation effect on nonmetallic inclusions.

This type of mesh filter is hardened with phenol resin etc. to give it shape retention properties, and is then used by placing it in the middle of the molten metal flow path such as the sprue or runner of the sand molding mold. General.

For example, FIG. 3 shows a state in which the mesh filter 25 is disposed on the mold dividing surface 24 that crosses the sprue 23 formed by transitioning from the upper mold 21 to the lower mold 22. The peripheral edge portion serving as a presser foot is held between the upper die 21 and the lower die 22. In the same figure, 26 is a plate-shaped filter installation core that supports the outer peripheral edge of the mesh filter 25 from below, 27 is the sprue bottom, 28 is a runner, and 29
3 is a product casting space, and 30 is a feeder casting space.

(Problem to be Solved by the Invention) However, the peripheral edge of the mesh filter 25 for use as a presser, that is, the portion held between the upper die 21 and the lower die 22, is at least 15 mm on one side with respect to the diameter of the sprue.
A certain degree is necessary, and the area is considerable relative to the cross-sectional area of the molten metal flow path.

For example, the specific dimensional relationship between the diameter of the hot water and the size of the mesh filter used is φ30 - angle 60,
φ40 - angle 70, φ50 - angle 80 (unit: mm), and the presser foot area/gate cross-sectional area was 2.3 to 4.1. Therefore,
It is desired to reduce the area of the presser foot to improve the substantial usable area (area of the filtration part) relative to the cost of the mesh filter.

On the other hand, the mesh filter installed in the mold as described above is easily damaged, requires careful handling, and is lightweight, and because it is simply placed on the dividing surface, it can be easily damaged with little external force. Misalignment is likely to occur, and there is also a risk of misalignment due to the impact when the upper and lower molds are clamped together, and may also be pushed downward by the impact of the molten metal during pouring, causing misalignment. , there is a dislike of not being able to hold a predetermined position.

The present invention solves these problems, eliminates the conventional method of holding the mesh filter between the upper and lower molds, allows the mesh filter to be held with a small amount of press, is easy to handle, and can be stably held in a predetermined position in the mold. It is an object of the present invention to provide a mesh filter body for filtering molten metal, which can be installed and which can be held at a predetermined position without shifting even when subjected to the impact of molten metal during pouring.

(Means for Solving the Problems) The mesh filter body for filtrating molten metal of the present invention, which has been made to achieve the above object, has an inner cylinder 2 at one end which has an opening that communicates with the molten metal flow path of the mold. A mesh filter 4 made of refractory fiber is applied across the opening, and a peripheral edge 5 of the mesh filter 4 extending outward from the inner cylinder 2 is used as a presser.
It is bent and held between the inner cylinder 2 and an outer cylinder 3 fitted to the outer periphery of the inner cylinder 2.

(Function) As described above, the mesh filter body of the present invention has the following features:
In the mesh filter 4, the peripheral edge 5 serving as a presser is bent and held between the inner tube 2 and the outer tube 3, so that a filtration surface under tension can be immovably formed on the upper surface of the opening of the inner tube 2. It will be done. Moreover, the peripheral portion 5 serving as a presser foot
Since it can be held between the inner and outer cylinders 2 and 3 with a slight bending, the amount of press required is small.

In addition, the inner and outer cylinders 2 and 3 protect the presser periphery 5 of the mesh filter 4 from contact with the outside, so that it is not damaged and is easy to handle. However,
The mesh filter body of the present invention has a moderate weight compared to a mesh filter alone, so it is stable when installed in a mold, and there is no displacement. Its installation is
The opening of the inner cylinder 2 is installed so as to communicate with the molten metal flow path of the mold. Preferably, a placement recess is provided on the placement surface of the mold, and the mold is placed so as to fit therein. The mesh filter 4 already has the inner and outer cylinders 2,
3, so it is stable against the impact when the upper and lower molds are closed and the impact from the pouring pressure during filtration of the molten metal, and is held in a predetermined position for stable filtration. carry out an action.

(Example) In FIGS. 1 and 2, reference numeral 1 indicates a mesh filter body for filtering molten metal according to one embodiment of the present invention. The mesh filter body 1 is a mesh filter made of refractory fibers, with an inner tube 2 and an outer tube 3 made of iron arranged concentrically, and a peripheral edge 5 for use as a presser foot being bent and held between the inner tube 2 and the outer tube 3. Consisting of 4,
It has a moderate weight. More specifically, the mesh filter 4 has a presser-replacement peripheral edge 5 at one end of the inner cylinder 2, which extends outward from the inner cylinder 2 and crosses the opening thereof. The mesh filter 1 is constructed by bending and sandwiching the mesh filter 1 with the fitted outer cylinder 3, thereby providing a filtration surface of the mesh filter 4 in a tensioned state on the upper surface of the opening of the inner cylinder 2, and the periphery thereof. The portion 5 is protected from contact with the outside by the inner and outer cylinders 2 and 3, so that it is not damaged and the mesh filter body 1 can be easily handled. The illustrated example of the mesh filter 4 is a mesh woven fabric sewn from fire-resistant fibers.

The inner diameter of the inner cylinder 2 is approximately the same diameter as the cross section of the molten metal flow path of the mold in which the mesh filter is installed, and therefore, the opening of the inner cylinder 2 has a molten metal flow having approximately the same diameter as the molten metal flow path of the mold. It communicates with the molten metal passage and acts as a molten metal passage. The inner circumferential surface of the inner cylinder 2 may be coated with a coating agent used in the casting industry.

A gap A between the inner tube 2 and the outer tube 3 is set to be about 0.1 to 0.3 mm larger than the thickness of the mesh filter 4. Further, the width of the presser foot peripheral edge 5 of the mesh filter 4, that is, the clamping width B (Fig. 1) is 2 to 5 mm.
It is sufficient to set a certain degree.

The inner cylinder 2 and the outer cylinder 3 can be easily obtained by cutting a thin-walled steel pipe such as a gas pipe into a ring shape to an appropriate length. Incidentally, it is preferable to provide a chamfered portion on the outer circumferential edge of the upper end of the inner cylinder 2 and the inner circumferential edge of the lower end of the outer cylinder, as shown in the figure. Thereby, the outer cylinder 3 can be easily fitted into the inner cylinder 2 via the peripheral edge 5 of the mesh filter 4 which serves as a presser. The mesh filter 4 is made of refractory fibers such as glass fibers and carbon fibers.

When using a high-melting metal molten metal such as cast iron or cast steel as the casting metal, it is preferable that the glass fiber has an SiO ₂ content of 75% by weight or more and has been pre-fired and shrunk. All kinds of cast iron molten metals with _SiO2 content above 75% (casting temperature 1200-1450℃)
It can be applied to
This is because it is possible to effectively prevent damage caused by shrinkage of the filter during passage of the molten metal.

Further, the mesh filter 4 may be used by applying a phenol resin or the like to give it shape retention, but as described above, the mesh filter 4 may be used in a bent state between the inner and outer cylinders 2 and 3. Then presser foot substitute peripheral part 5
Since it can be used as it is without applying such a shape-retaining agent, in this case, it is possible to reduce the cost of the refractory fiber.

Generally, the opening size of the mesh filter 4 is usually 0.4 to 4 ^mm2 , although it depends on the size of nonmetallic inclusions such as slag and slag to be removed.

Note that the flat shape of the net-like woven fabric 4 before it is attached to the inner cylinder 2 is usually such that the filter surface section that crosses the upper surface of the opening of the inner cylinder 2 has the above-mentioned shape from the viewpoint of ease of cutting. Generally, a rectangular type with a continuous presser foot margin 5 serving as a clamping margin B is used.

Incidentally, the inner and outer cylinders 2 and 3 constituting the mesh filter body 1 for sprue diameters of φ30, φ40, and φ50 mm are shown below.
An example of the specific dimensions (unit: mm) of the mesh filter that is folded and clamped is shown below. Note that the inner tube 2 and the outer tube 3 were fabricated using thin-walled steel pipes with a thickness of 1 mm.

Minimum clamping allowance Reticulated woven fabric dimensions Gate diameter φ30… 2 Corner 36 〃 φ40… 3 Corner 48 〃 φ50… 5 Corner 62 In the above example, clamping clearance area/gate area is 0.44~
0.54, which makes it possible to significantly improve the actual usable area of the mesh filter compared to the conventional example described above. The clamping area is expressed as (total area of mesh filter - area of sprue).

FIG. 2 shows the mesh filter body 1 explained above.
FIG. 3 is a sectional view showing a state in which the sand mold is installed in a sand molding mold.
In this mold, a sprue 13 is formed by transitioning from an upper mold 11 to a lower mold 12, and a mold dividing surface 1 of the lower mold 12 is formed.
4, an installation recess 15 is provided on the inner peripheral surface of the sprue 13. According to the present invention, the mesh filter body 1 is fitted into the recess 15 with the mesh filter 4 positioned above the sprue. In this state, the opening of the inner cylinder 2 communicates with the sprue 13 with approximately the same diameter. In the same figure, 1
Reference numeral 6 denotes a runner, and a product casting space and the like are formed at the end of this runner.

In this way, the mesh filter body 1 according to the present invention
As mentioned above, the filter has the advantage of being extremely easy to install at a predetermined location on the inner peripheral surface of the sprue of the mold, and the filter installation core 26 is installed in the mold as in the conventional method. After that, not only is the troublesome work of installing the mesh filter 25 on the upper surface thereof improved, but also the peripheral edge 5 of the mesh filter 4 is bent between the inner cylinder 2 and the outer cylinder 3. Since the upper mold 11 is clamped in this state, it is protected from damage and is easy to handle.
The filtration surface at the center of the filtration surface performs a stable and good filtration action without causing displacement due to the impact when the lower mold is closed or the molten metal from pouring.

(Effect of the invention) As described above, according to the invention, the reticular filter 4 made of refractory fiber is attached to one end of the inner cylinder 2 across the opening thereof, and extends outward from the inner cylinder 2. Since the peripheral edge 5 for use as a presser foot is bent and held between the inner cylinder 2 and the outer cylinder 3 fitted thereto to constitute the mesh filter body 1 for filtrating molten metal, the peripheral edge 5 of the mesh filter 4 The pressing allowance B is significantly smaller than that of the conventional mesh filter which is held between the upper mold and the lower mold, increasing the practical usable area. This has the effect of being able to be installed immovably with the filtration surface tensed on the upper surface, and at the same time, the presser peripheral edge 5 of the mesh filter 4 is protected from contact with the outside by the inner and outer tubes 2 and 3, thereby preventing damage. Furthermore, since the mesh filter body 1 has an appropriate weight, it can be stably installed on the installation surface of the mold, and by communicating the opening of the inner cylinder 2 with the molten metal flow path. , it is possible to form a stable filtering surface, and since the mesh filter 4 is already firmly bent and held by the inner and outer cylinders 2 and 3, there is no shock or molten metal pouring when the upper and lower molds are closed. It is stable against impact caused by hot water pressure during filtration, and has the advantage of being able to perform a stable filtration action without shifting position.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway cross-sectional view of an example of the mesh filter for filtrating molten metal according to the present invention, FIG. 2 is a cross-sectional view of the mesh filter body installed in a sand molding mold, and FIG. FIG. 3 is a sectional view of a sand molding mold in which a conventional mesh filter is installed. 1...Mesh filter body, 2...Inner cylinder, 3...
Outer cylinder, 4...mesh filter, 5...peripheral edge for presser foot.

Claims (1)

[Scope of utility model registration request] A reticular filter 4 made of refractory fiber is attached to one end of the inner cylinder 2 having an opening communicating with the molten metal flow path of the mold, crossing the opening.
A mesh filter for filtrating molten metal, in which a peripheral edge 5 of the mesh filter 4 extending further outward, which serves as a presser, is bent and held between the inner cylinder 2 and an outer cylinder 3 fitted to the outer periphery of the inner cylinder 2. body.