RU2509594C2 - Krapukhin's filter element - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to filtration. Proposed element comprises filter baffle composed of cylindrical coil, covers connected to it ends, union to fluid or gas feed and discharge and resilient element arranged between carcass and cover. Coils turns are composed by interconnected alternate arcs with different radii of curvature, the number of arcs in every turn is other than integer.

EFFECT: higher efficiency.

6 dwg

Description

The invention relates to devices for filtering liquids and gases, including radioactive and aggressive, in nuclear and thermal power plants, in the oil and chemical industry for filtering gasoline, kerosene and other organic and inorganic liquids and gases, in vehicles for cleaning fuels, oils and air, in the manufacture of paints, in the construction and food industries, in parasitology for the extraction of parasitic objects from water, in everyday life for water treatment, in oil production for the treatment of formation water, metallurgy and other fields of human activity.

Known filter element containing a filter partition and mounting and connecting elements; filter gaps in the element are formed between the turns of the wire spiral (UK patent No. 1388356, CL B01D 29/48, 1975).

The specified filter element has satisfactory filtering characteristics, but its regeneration is difficult due to irreversible clogging of the filter channels with particles of the solid phase, which leads to a complete cessation of the filtering process and unsuccessful attempts to regenerate by the reverse fluid flow.

In USSR author's certificate No. 1368003 (class B01D 29/44, 1986), the problem of regeneration of the filter element is solved by stretching the filter partition and increasing inter-turn gaps in the backwash of the washing liquid. An increase in the length of the filtering septum contributes to the destruction of the solid phase collected on the surface of the filtering element and facilitates the access of the washing liquid to the surface of the filtering septum; the quality of the regeneration of the filter element is improved.

The specified copyright certificate (No. 1368003) is the closest analogue to the proposed technical solution. The slot filter according to the indicated technical solution contains a filtering partition in the form of a spiral, the turns of which are made in the form of polygons, the vertices of which are displaced relative to each other.

The main disadvantage of this device according to the USSR author's certificate No. 1368003 is that the values of the obtained filter gaps depend on the number of faces of the polygons. In the manufacture of filter baffles with the number of faces 3, 4, 5, 6 and 7 from a wire with a diameter of 0.7 mm, filter gaps in the form of triangles can be obtained, the maximum vertex lengths of which will be 2450, 964, 319, 66 and 18 μm, respectively. Attempts to obtain gaps of intermediate value due to the displacement of the vertices of the polygons relative to each other, as indicated in the copyright certificate, lead to an increase in the contact areas of the turns and are difficult to technically accomplish.

The purpose of the invention: expanding the range of filter gaps and increasing the performance of the filter walls by reducing the contact area between the turns.

Figure 1 shows a vertical section of a filter element. The filter element contains a filter baffle 1, a frame 2 and an elastic element 3 made in the form of a compression spring. The upper end of the filtering partition is closed by a blank cover 4, and the lower end is equipped with a fitting 5 for supplying and discharging liquid or gas.

Figure 2 shows a top view, figure 3 is an enlarged end view of the first two turns of the filtering partition. 5 and 6 are examples of the formation of filter gaps between two adjacent turns of filter partitions.

The filtering partition is made in the form of a helical spiral. The turns of the spiral are in contact with each other; they are formed from alternating and conjugate arcs with small r and large R radii of curvature. Figure 3 turns are formed by 10 conjugate arcs with small radii of curvature r: r1, r3, ... r9 and large R: R2, ... R10. Figure 4 shows a vertical section of two adjacent turns of the filter partition in an enlarged scale and the size of the filter gap 8 between adjacent contacting turns. Figure 5 shows the enlarged end face of the first two turns of the filtering partition with the number of arcs - 14 (with radii r: from r11 to r23 and radii R: from R12 to R24). Figure 6 shows the end face of the first two turns of the filtering partition formed by 18 arcs also with different radii of curvature: with radii r from r25 to r41 and with radii R: from R26 to R42. The number of arcs in each turn is different from the whole.

Filter gaps 8 can be determined by the formula below and derived on the basis of geometric constructions:

$$\delta =\sqrt{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="00000003.png"\; state="\{\{state\}\}">d</figure-callout>}}^2+{\left[\frac{\left(D-d\right)}{2}\cdot \left(\mathrm{one}-\cos \frac{360}{N}\right)\right]}^2}-d$$

where: S is the linear size of the bore formed in the longitudinal radial section of the element between adjacent turns having an apex in the form of an arc with a radius of curvature r and an arc with a radius of curvature R (see figure 4);

D is the outer diameter of the filter partition, determined by the cylinder describing the outer diameters of the arches of the filter partition with a radius of curvature r;

d is the diameter of the wire;

N is the number of vertices in two turns of the filtering partition.

The number of arcs placed within 360 ° must be different from an integer, so that displacements of arcs with equal radii of curvature relative to each other are ensured, since it is this displacement that provides the formation of filter gaps. If arcs with equal radii of curvature will not have an angular displacement relative to each other, then the filter gaps will be equal to zero. To obtain gaps of various sizes within the same overall dimensions of the filtering partition, a number of techniques can be used: for example, increase or decrease the number of arcs and obtain a corresponding decrease or increase in the values of filter gaps; change the ratio of the radii of curvature of the arcs following each other; change the angular shift of the arcs relative to each other. However, in any case, the number of arcs with equal radii of curvature placed within the same turn should not be an integer.

The total filter gap of the entire filter element is determined by the size of the filter gaps, the number of gaps on the circumference of one turn and the number of turns of the spiral. A decrease in the number of contact spots of the contact of the turns of the spiral leads to an increase in the effective area of the filtering surface.

The frame of the element can be located both outside and inside the filter partition.

The filter element operates as follows.

During cleaning, the filtered stream is directed outside the filter membrane, passes through it into the filter element and leaves the filter element through the fitting. When filtering, the pressure inside the filter element is less than outside, since the fluid flow loses part of its energy in the direction of travel, overcoming the hydraulic resistance of the sediment collected outside the filter surface and the resistance of the filter partition. This differential pressure compresses the coils of the spiral until they touch and ensures the stability of the filter gap. However, during regeneration by the reverse flow of liquid or gas, the flow moves from the inside out and stretches the spiral, overcoming the resistance of the elastic element and the sediment; the solid phase is washed out of gaps by this reverse flow.

In this technical solution, due to the execution of spiral turns from arcs with specified different radii of curvature, the total contact area of adjacent turns can be reduced and the total effective area of filter gaps can be increased. This gives a more favorable ratio of the area of filter gaps to the area of the filter partition than the known filter elements; the performance of the filter element and, accordingly, the filtering equipment performed on its basis are increased.

Claims (1)

A filter element comprising a filter baffle made in the form of a cylindrical spiral and a cap and a fitting for supplying and discharging liquid or gas attached to its ends, respectively, a frame and an elastic element located between the frame and the cover, characterized in that the coils of the spiral are formed from alternating arcs with different radii of curvature and conjugate to each other, and their number in each of the turns is different from the whole.

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