WO2010119301A1

WO2010119301A1 - Fluid filter

Info

Publication number: WO2010119301A1
Application number: PCT/HU2010/000042
Authority: WO
Inventors: Lajos Simon
Original assignee: Lajos Simon
Priority date: 2009-04-14
Filing date: 2010-04-12
Publication date: 2010-10-21
Also published as: HU3614U; HU0900073V0

Abstract

The fluid filter according to the invention contains a filter holder made of a ribbed pipe and a filter element arranged on said ribbed pipe, wherein said filter element is a filter spiral (3) and the ribs (2) of the ribbed pipe (1) are provided with V-shaped notches (4) arranged in transverse direction with respect to the ribs (2), wherein the distance (x) between the lower edge (5) of the notches (4) and the outer cylindrical surface of the ribbed pipe (1) is at least 0,5 mm; and the cross section of the filter spiral (3) arranged in the notches (4) forms essentially a triangle, wherein the two corners of the triangle, not supported in the notches (4) are provided with cutoffs (7) defining a gap (6) between the windings of the filter spiral (3) coiled on the ribbed pipe (1), said gap (6) having walls parallel with each other.

Description

FLUID FILTER

The object of the present invention is a fluid filter, mainly for use in water wells. Fluid filters used in water wells or for filtering of fluids contaminated with micro or macro particles generally contain a filter holder and a filter element arranged on the holder.

Filter holders are generally metal structures made of longitudinal and transverse rods, wires or rings fixed on the rods. The filter element may be sieve, geo-textile or some coiling.

DE 2512781 discloses a filter patron containing a filter holder made of longitudinal rods and a wire spiral coiled around the rods. The windings of the wire carry the filter element, which is a sieve.

A vacuum filter apparatus is described in the US 3.919.088, containing a filter drum. The filter drum is a cylindrical member comprised of a series of parallel longitudinal bearing strips and holding rings having the cross section of a triangle, for bearing the filter element, which is a sieve.

Another filter construction contains a filter element, which is made of rings having triangular cross sections (HU 209 861). The production of filter holders made of longitudinal metal rods and/or metal spiral is rather difficult, awkward and expensive, the longitudinal rods easily deform during use and the smaller ones are liable to buckling.

A further problem arising in connection with such filter holders is that the longitudinal rods should be connected to end pieces of rather complicated con- struction and, therefore, filters of this type are rather expensive.

The object of the Hungarian Utility Model No. 2667 is therefore a fluid filter, wherein the filter holder is a simple and cheap ribbed pipe, which can easily be prepared and used for many purposes. This pipe can held different types of filter elements, such as filter spiral. The pipe, if used as filter holder, is provided with holes or slots between the ribs.

Such a ribbed pipe can be used as filter holder like the prior metal rod or ring structures, and can simply be prepared by extrusion. In this way, it is cheap and can be used without difficulty in any types of filters of any parameters. The ribs may be higher ribs having triangular or trapezoidal cross section and lower ribs with arcuate, preferably semicircular cross section. However, the ribs may have many other embodiment, they may have rectangular cross section as well. A serious drawback of the above known construction is that the location of the spiral filter element on this type of filter holder does not always provide the required accuracy.

Therefore, the object of the present invention is to provide a fluid filter, which can simply be prepared, is cheap and can be used without difficulty for any types of filters of any parameters and, further to that, enables filtering with very high precision.

Accordingly, the fluid filter of this invention contains a filter holder made of a ribbed pipe/pipe and a filter element arranged on said ribbed pipe, wherein said filter element is a filter spiral and the ribs of the ribbed pipe are provided with V-shaped notches arranged in transverse direction with respect to the ribs, wherein the distance between the lower edge of the notches and the outer cylindrical surface of the ribbed pipe is at least 0,5 mm, preferably 0,5 to 2,0 mm, and the cross section of the filter spiral arranged in the notches is essentially a triangle. The two corners of the triangle, not resting in the notches are provided with cutoffs defining a gap between the windings of the filter spiral coiled on the ribbed pipe, said gap having walls parallel with each other. Preferably, the height of said gap is equal to or lower than the width of the gap.

Preferably, there is a steel wire embedded in the filter spiral, said steel wire being co-extruded with the filter spiral. The invention is based on the recognition, that the drawbacks of the prior art rod and rings or slotted pipe filters can be eliminated if the filter spiral is coiled on a high strength ribbed pipe, and the accuracy of the filter gap is achieved by exact positioning of the filter spiral and by mechanical working of the walls of the gap. Further details and advantages of the invention will be explained by examples and with reference to the attached drawing, wherein

Fig. 1 is a perspective view of a preferred embodiment of a known ribbed pipe used in the fluid filter according to the invention; Fig. 2 is a side view of a section of the ribbed pipe provided with a filter spiral;

Fig. 3 is a longitudinal section of a part of the filter of Fig. 2; Fig. 4 is a longitudinal section of a part of another embodiment of the filter and

Fig. 5 is the cross section of a preferred embodiment of the filter spiral.

Fig. 1 shows a known ribbed pipe 1, which is provided with longitudinal spiral supporting and spiral holding ribs 2 spaced in uniform parallel relationship to each other. The supporting ribs are essentially of semicircular, the spiral holding ribs of triangular cross section. Other and further embodiments and variations are also possible: supporting ribs of rectangular or rounded quadratic cross section, and spiral holding ribs of trapezoid or parabolic cross section as well. Many other cross sections may also be applied. In some cases all the ribs may have the same shape.

Perforation, i.e. holes and/or slots (which are not shown in the drawing) are arranged in the wall of the ribbed pipe, between the ribs.

The ribbed pipe shown in Fig. 1 can preferably be applied as filter holder of water filters, as it can easily be produced, it is cheap, the filter element can be fixed on the ribs quickly and safely, and it may be used in many different filters.

The ribbed pipe does not deform during use and offers easy maintenance and cleaning. Therefore, it is excellent for being used in fluid filters, instead of the prior metal rod constructions. Preferably it is made of hard PVC or polyethylene. Fig. 2 shows a side view of a section of the ribbed pipe 1 , wherein a filter spiral 3 is coiled around the pipe, as suggested according to the present invention. Fig. 3 shows a longitudinal section of a part of the filter of Fig. 2, wherein a spiral holding rib 2 can be seen with a filter spiral 3. Rib 2 is provided with V- shaped notches 4 adapted for precisely holding the filter spiral 3. The depth of the notches should be enough to offer room between the outer surface of pipe 1 and the filter spiral 3 for flowing the medium to be filtered. This can be achieved, if the distance x between the lower edge 5 of the notches 4 and the outer surface of the pipe 1 is at least 0,5 mm, preferably 0,5 to 2 mm. Fig. 4 shows a side view of a section of the ribbed pipe 1 , with another type of rib 2. This rib 2 is lower than the other and has a semicircular cross section, but is provided with similar notches 4. As the height of this rib is smaller, and the distance x between the lower edge 5 of the notches 4 and the outer sur- face of the pipe 1 should be kept at the same value, as in Fig. 3., the depth of the notches should be smaller, than that of the first embodiment. In this way, the diameters of the outer cylindrical surface of both filter spirals 3 are the same.

Fig. 5 shows the cross sectional view of a filter spiral 3, which is essentially triangular, wherein the two corners (shown with dotted lines) not sitting in a notch 4 are provided with cutoffs 7 defining a gap 6 between the windings of the filter spiral 3 coiled on the ribbed pipe 1(see Figs 3. and 4.). The gap 6 has walls in spaced parallel relationship with each other and is adapted for carrying out filtering in the structure shown in Fig 2. The length of the cutoffs 7 should be adjusted in a way that the height h (Fig. 5.) of the gap 6 should not be greater than the width s thereof (Figs. 3 and 4).

The spiral filter 3 is provided with an inner steel core wire 8, which is co- extruded with the spiral, for assuring sufficient elasticity, and keeping the elements of the filter together, if the spiral is damaged.

From the foregoing it will thus be apparent that the fluid filter according to the invention is much more stable construction, than the prior art rod and spiral type filters, and has, at the same time, much greater, about twice as great open filter surface, than the usual ribbed pipe filters.

A further advantage is that, to the contrary to the gap width of minimum 0,5 mm of the prior art ribbed pipe filters, it can be produced with a gap width s as small as 0,1 mm. Furthermore, the gap in the fluid filter according to the present invention is uniform and exact in size, as the filter spiral is precisely guided by the notches in the ribs. The more so, as the walls of the gap are not uneven extruded walls, but exactly turned surfaces.

Although particular embodiments of the invention have been illustrated in the accompanying drawing and described in the foregoing description, it will be understood that the invention is not limited only to the embodiments disclosed, but is intended to embraces any alternatives and modifications falling within the scope of the following claims.

Claims

1. Fluid filter, mainly for use in water wells, containing a filter holder made of a ribbed pipe and a filter element arranged on said ribbed pipe, characterized in that said filter element is a filter spiral (3) and the ribs (2) of the ribbed pipe (1) are provided with V-shaped notches (4) arranged in transverse direction with respect to the ribs (2), wherein the distance (x) between the lower edge (5) of the notches (4) and the outer cylindrical sur- face of the ribbed pipe (1) is at least 0,5 mm; and the cross section of the filter spiral (3) arranged in the notches (4) is/forms essentially a triangle, wherein the two corners of the triangle, not supported by a notch (4) are provided with cutoffs (7) defining a gap (6) between the windings of the filter spiral (3) coiled on the ribbed pipe (1), said gap (6) having walls pa- rallel with each other.

2. The fluid filter as claimed in claim 1 , characterized in that the distance (x) between the lower edge (5) of the notches (4) and the outer cylindrical surface of the ribbed pipe (1) is 0,5 to 2,0 mm.

3. The fluid filter as claimed in claim 1 or 2, characterized in that there is a steel wire (8) embedded in the filter spiral (3), said steel wire being co- extruded with the filter spiral (3).

4. The fluid filter as claimed in any of claims 1 to 3, characterized in that the height (h) of said gap (6) is equal to or lower than the width (s) of that gap (6).