DK167097B1 - Filter unit for separating out heavy particles, preferably amalgam-containing sludge from the waste water from dental clinics, and which consists of a container having an inlet and an outlet, into which container a filter element, which contains spheres, is incorporated - Google Patents

Description

-1- DK 167097 B1 DESCRIPTION.

The present invention relates to a filter unit of the kind referred to in the preamble of claim 1.

Such filter units are known from the descriptions of US Patent No. 4,385,891, EP Patent No. 284,641, DE Patent No.

3 030 614, DE Publication No. 3 813 264 and EP patent application 333 673.

It is a disadvantage of these known filter units that they either require connection to an additional suction device or that they comprise an electrolysis or centrifugal device driven by a fast-running motor. These filter units are thus complicated in their construction and therefore expensive to manufacture and expensive to operate.

Further, from the specification of Danish Patent Application No. 2504/83, such a filter unit is known comprising one or more filter elements containing a mixture of large and small balls of alumina which have either greater or lesser density than water and are enclosed between two wire meshes, and below the filter elements a settling zone. During the flow, the water first passes the sedimentation zone and then the filter. During the flow in the sedimentation zone, the flow is turbulent. Heavy particles in the water such as amalgam will therefore tear with the flow of water and pass to the 25 filter.

Each filter element flows through the entire volume of water. During flow, the heavy spheres are lifted from the lower filamentous tissue and lie on the underside of or mixed with the light spheres retained at the top of the upper filament web. When the flow of water is interrupted, the heavy balls sink and settle on the lower wire mesh. During these movements, the amalgam that has deposited on the spheres will be shaken off and either settle on the bottom wire mesh or pass this down into the sedimentation zone where there is a risk that it will be tipped off by the water flow and returned to the filter. . Amalgam-containing sludge, which has settled on the lower -2 DK 167097 B1 wire unit, will be swirled up during the next flow. Since each filter element must be passed by the entire volume of water and since the heavy balls must be lifted by the water flow, it is expected that there is a large flow resistance in the filter. The filter unit must therefore be positioned so that the pressure height becomes large, which is not always possible, or it must be designed such that the filter elements have a large flow area, whereby the filter unit becomes correspondingly large.

It is an object of the present invention to provide a filter unit which is simple in its construction, which does not require the attachment of additional equipment such as suction or centrifugal devices, and which provides little resistance to the flow of water and therefore has high capacity at the same time. with little space required and low pressure height.

This is achieved by designing the filter unit as set forth in the characterizing part of claim 1.

This ensures that the flow in the outer chamber becomes 20 turbulence free, whereby in this chamber a sedimentation takes place, so that heavy particles such as amalgam sink to the bottom and partly a filtration. The following chamber is centrifuged so that any heavy particles carried by the water flow are collected at the outside of the wall of the chamber 25 and sink to the bottom. In the next chamber, a further spin is performed. Since the cross-sectional area of this chamber is smaller than that of the previous chamber, the water velocity is greater and the centrifugation correspondingly more powerful so that any small amalgam particles carried with the water stream are separated here.

Claim 2 relates to a preferred size of the balls of a filter unit according to the invention.

The invention will be explained in more detail below with reference to the drawing, in which FIG. 1 shows a vertical section through a filter unit according to the invention, and DK 167097 B1 -3- FIG. 2 shows a horizontal section along line I-I in FIG. First

As shown in the drawing, a filter unit according to the invention consists of a cylindrical container 1 having an inlet 2 for 5 purified wastewater and a drain 3 for purified wastewater.

The filter unit is formed with three chambers 5, 6 and 7 of circular cross section. These chambers are separated by tubular partitions 8 and 9, respectively, which are arranged concentrically in an outer tube 10. In the center of the filter unit a 10 drain pipe 11 is arranged. the following chamber 6, which again has greater cross-sectional area than the next chamber 7. The water velocity is therefore greater in chamber 7 than in chamber 6, where it is again greater than in chamber 5.

The inlet 2 is connected externally to the outer tube 10 on the upper third of the tube. The drain is connected to the top of the drain pipe 11. In the dividing walls 8 and 9 and in the drain pipe 11, passage openings 12, 13 and 14, respectively, are placed above the inlet 2 and in the increasing distance therefrom. Seen in a horizontal plane, the openings 12, 13 and 14 are offset approximately a whole circumference, e.g. 340 °, relative to each other. Between the inlet 2 and the opening 12 in the outer chamber 5, between the openings 12 and 13 in the following chamber 6, and between the openings 13 and 14 in 25 chamber 7, dividers are mounted 15. This forces the water flow to move as shown by arrows. in FIG. 2. The chamber 5 is about 1/3 filled with hollow plastic balls which can have an outside diameter of 10® mm.

The pipes 8, 9 and 10 are mounted at the ends in end pieces 17 30 and 18 and the parts are held together by a screw 19 with a nut 20. Thus, the filter unit can be separated, cleaned and reassembled.

When the filter unit is in operation, the outer chamber 5 will be filled with water and PVC balls and the PVC balls 16 will accumulate 35 in the upper third of the chamber. The balls closest to the inlet 2 will cause the flow to be turbulence free. Since the water will move along the path where the current resistance is least, it will move obliquely through the PVC balls 16 located closest to the inlet 2 around the chamber 5 and obliquely up through the PVC balls 5 located closest to the passage opening 12, the balls thus acting as a filter.

Thus, on the first part of the flow through the outer chamber 5, a sedimentation occurs, where heavy particles such as amalgam settle to the bottom and settle on the bottom of the chamber, and on the last part of the flow a filtration takes place.

In the two following chambers 6 and 7, centrifugation takes place so that material not separated in the outer chamber is separated in these chambers. Thus, in the filter unit, both sedimentation, filtration and centrifugation occur. The filter unit therefore has a great cleaning effect. On a filter unit, mounted on the saliva basin of a dental clinic, it has been shown by measurements that only 0.4% of the amount of amalgam supplied is discharged. The rest is retained in the filter. Due to the low water resistance, the filter unit can be manufactured with a diameter of only 11 cm and a height of 30 cm.

Such a filter has a capacity of up to 4.0 liters / min.

25

Claims (2)

A filter unit for separating heavy particles, preferably amalgam-containing sludge from the wastewater from dental clinics, consisting of a container (1) with an inlet (2) and a drain (3) into which a filter element is incorporated, containing balls, characterized in that the filter unit consists of three chambers (5,6,7) of circular cross-section and with decreasing cross-sectional area from chambers (5) to 10 chambers (7), which chambers are separated by tubular partitions, respectively (8 ) and (9) located concentrically in an outer tube (10) and of an inner drain tube (11) located concentrically within the tube (9) that the inlet (2) is connected externally to the tube (10) ) on the top 15 third of this through an inlet opening (2 ') and the drain (3) connected to the top of the pipe (11), that in the partitions (8) and (9) and in the pipe (11) there are passage openings , (12), (13) and (14), respectively, located above the inlet opening (2 ') and at increasing distances and from which, in a horizontal direction, are displaced approximately one whole circumference, e.g. 340 °, relative to each other and relative to the inlet (2), that in the chambers (5), (6) and (7) between the openings (21) and (12), (12) and (13) respectively (13) and (14) are integral partitions (15) and the chamber (5) is partially filled with air-filled PVC balls (16). Filter unit according to claim 1, characterized in that the balls (16) have a diameter of 8® mm.