JPS62220270A - Manufacture of metal made filter element - Google Patents

Abstract

PURPOSE:To obtain the filter element having the service life as scheduled without any clogging due to the immersion of a brazing filler metal by using the joining material mixing a brazing filler metal and the metal powder body of higher melting point than that and by joining a metal made filter body and end plate by melting only the brazing filler metal. CONSTITUTION:The joining material 2 mixing a brazing filler metal and nickel powder is sprayed on the end plate 1 of the filter element in a doughnut shape and one end face of a metal made cylindrical filter body 3 is overlapped thereon. A weight 4 is then placed on the other end face of the filter body 3 and inputted into a vacuum furnace and after heating taken out of the furnace and cooled at the room temp. The joining material 2 maintains a comparatively high viscosity without melting the nickel powder with the brazing filler metal only being melted in the furnace. The filter body 3 and end plate 1 are therefore joined without the immersion of the joining material 2 to the filter body. The joining materials 2 is then sprayed on the other end plate 5, the filter body 3 is overlapped upside down, heated inside the vacuum furnace similarly as before with pressing by the weight 4 and cooled at a room temp. after heating.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a metal filtration element for reliably fixing an end plate without clogging a metal porous filter. This relates to a manufacturing method.

(Prior art) As a filter element for filtering high-temperature fluids and corrosive fluids, there is a filter element in which an end plate is bonded to a metal porous filter body made of a sintered alloy or a pleated cylindrical wire mesh. It is used.

The joint portion between the filter body and the end plate of the filter element needs to withstand high temperatures and corrosion like the filter body.

Conventionally, bonding using a resin adhesive, arc welding, or sintering is known as a means for bonding a filter body and an end plate. However, those using adhesives are not heat resistant, those using arc welding require considerable welding allowance, which reduces the effective area of the filter medium, and those using sintering require wire mesh with uneven heights at the joints. All of them have drawbacks, such as the inability to seal against filter media.

(Problems to be solved by the invention) In the conventional conventional joining of the filter body and end plate by ordinary brazing,
The molten brazing filler metal is sucked up into the filter by capillary action, becomes clogged, and solidifies as it is, so the filtration area becomes smaller than the planned value and the element life cannot be maintained as planned.

In addition, the amount of brazing filler metal may decrease at the joint, resulting in insufficient bonding force or poor sealing.

(Means for Solving the Problems) This invention solves the above-mentioned problems of brazing.
This is a method for manufacturing a metal filtration element without reducing the filtration area and without insufficient bonding strength or poor sealing.

That is, when brazing a cylindrical metal porous filter body and a dish-shaped end plate, a bonding material containing a powder brazing material and a metal powder having a higher melting point than the brazing material is interposed between the two. In this method, the filter element is manufactured by heating and brazing the brazing material to a temperature at which only the brazing material melts.

(Action of the invention) In this invention, the lζ
The chemical properties of the bonding material are maintained because the brazing material and powder must be physically mixed. This causes the wax to melt, but not the powder. Therefore, the powder mixed into the molten brazing filler metal works to increase the viscosity of the molten brazing filler metal, and the brazing filler metal maintains a relatively high 1 degree Celsius, so that penetration into the filter medium is not a practical problem. Being held down.

Embodiments of the present invention will be described below with reference to the drawings.

(Example 1) On the end plate 1 of a donut-shaped filter element, a bonding material 2 made of a mixture of 40% (by weight) brazing filler metal (BNi-5) and 60% (f7@) powdered nickel powder was placed on the end plate 1 of a donut-shaped filter element. was sprinkled, and one end surface of the cylindrical metal filter body 3 was placed on top of this.Then, a weight 4 was placed on the other end surface of the metal filter body 3, and it was placed in a vacuum furnace and pressurized at 1120° C. for 25 minutes. After heating, it was taken out from the furnace and cooled to room temperature.

Since the melting point of the soldering material is 1050°C and the melting point of the nickel powder is 1459°C, only the brazing material melts in the furnace, the nickel powder does not melt, and the bonding material 2 as a whole has a relatively high temperature. Maintained viscosity. Therefore, the bonding material 2 hardly penetrated into the filter body, and the filter body 3 and the end plate 1 were bonded.

Next, after spraying the bonding material 2 on the other end plate 5, the filter body 3 was stacked upside down on top of the bonding material 2, and while being pressurized with the weight 4, it was heated in a vacuum furnace in the same manner as described above.

When the filter element was taken out after heating and cooled to room temperature, it was possible to obtain a filter element in which almost no penetration of the bonding material 2 into the filter body was observed.

In the above, during the process of joining the end plates 5, no flow of the bonding material for joining the end plates 1 was observed.

This is considered to be because the brazing material and the nickel powder were chemically bonded to each other at J5 under high temperature when the end plates 1 were heated for joining, thereby increasing the melting temperature of the brazing material.

Therefore, if the upper and lower end plates 1.5 are bonded in separate steps as in this embodiment, the bonding material 2 will not flow down, and the filter element will be created in which the penetration of the bonding material 2 into the filter body 3 is as small as possible. It will be possible to do 1q. Of course, if the mixing ratio of powder such as nickel powder is increased, the viscosity of the bonding material will increase accordingly, so if the viscosity of the bonding material is high enough, the upper and lower end plates may be heated and bonded at the same time. There is little risk that the bonding material will flow down.

The powder is used to increase the viscosity of the molten brazing filler metal, so it has a higher melting point than the brazing filler metal (in terms of work, the difference in melting point is 2.
00 degrees Celsius or higher), there are no restrictions on the material, and multiple types can be mixed, but nickel powder, SO3 powder, and other metal powders are generally used. The mixing ratio of the powder should be such that the degree of penetration of the bonding material into the filter medium can be reduced to a level that does not cause any practical problems, and is preferably in the range of 30% to 90% (by weight) for practical purposes. It is considered to be in the range of 40% to 70% (1 maximum).

(Example 2) In the example shown in FIG. 3, a gold-flexible fiber sintered body is interposed at the joint between the filter body and the end plate. That is, the bonding material 2, which is a mixture of brazing filler metal and nickel powder, is spread on the top surface of the end plate 1, the metal fiber sintered body 6 is laid on top of this, and the bonding material 2 is further spread on top of this. After placing the metal filter 3 on top and heating under pressure in a vacuum furnace (<1120°C, 25 minutes),
After cooling at room temperature, the end plate 1 and the metal filter body 3 were joined.

Next, the upper end plate 5 was also joined in the same manner to obtain the filter element shown in FIG. 3.

In this embodiment, the bonding material 2 is interposed on both the upper and lower surfaces of the metal fiber sintered body 6, but the bonding material may be interposed only on either the lower surface or the upper surface.

When the bonding material is interposed only on the lower surface, even if the viscosity of the four bonding materials is relatively low (at least the proportion of powder) is sufficient.

In this embodiment, the bonding material 2 is integrated with the metal fiber sintered body 6 by melting and resolidifying the bonding material 2.

Since the metal fiber sintered body 6 acts as a backing that fills the gap between the end face of the filter body and the end plate, even if the end face is a metal mesh filter material that tends to be uneven, it will be airtightly joined.

(Effects of the Invention) The present invention provides a filtration method that uses a bonding material that is a mixture of a brazing filler metal and a metal powder having a higher melting point than the brazing filler metal, and avoids melting only the brazing filler metal, thereby bonding a metal filter body and an end plate. Since this is an element manufacturing method, there is no clogging due to penetration of the brazing filler metal, and there is no reduction in the filtration area, so a filtration element with a planned lifespan can be obtained. Furthermore, since the brazing material is not reduced at the joint, this manufacturing method does not cause insufficient joints or poor sealing.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the joining process of one end plate in the first embodiment, Fig. 2 is a sectional view showing the joining process of the other end plate, and Fig. 3 is a sectional view showing the joining process of the other end plate. It is a sectional view of a filter element. 1.5... End plate 2... Bonding material 3... Filter body 6... Metal fiber sintered body Fig. 1 Fig. 2

Claims (1)

[Claims] 1. A bonding material made of a powdered brazing material and a metal powder having a higher melting point than the brazing material is interposed between the cylindrical metal porous filter body and the dish-shaped end plate. After that, the joining material is heated to a temperature at which only the brazing material melts, thereby melting the brazing material and thereby joining the filter body and the end plate. Method 3 for manufacturing a metal filtration element according to claim 1, wherein the bonding material and the metal fiber sintered body are interposed between the body and the end plate. A method for manufacturing a metal filtration element according to claim 2, in which the element is interposed on one surface.