FI77992C - Absorption material for filter arrangements - Google Patents

Description

77992

The present invention relates to an absorption material for a filter device. In rooms where troublesome gases are formed, suction devices are usually used, including a filter for collecting constituents which must not be allowed to enter the space outside those rooms. Filters that collect inconvenient components in the gases are also placed in front of the outlets of the substances that emit the inconvenient gases. Carbon particles have heretofore been used as such an absorbent material. In practice, it has been found that such filters containing carbon particles are not efficient enough to remove liquid particles from the flowing gaseous substance.

The object of the present invention is to take care of liquid particles in an efficiently flowing gaseous substance. This is accomplished by using one or more pieces that contain closed, torn spaces. The pieces may suitably consist of foam in which the enclosed spaces are routed.

The filter may be formed of one or more parallelepiped-shaped pieces or may consist of a housing containing a plurality of smaller, compressed pieces of different shapes.

The filter can also be made of a mat or strip-like body that is twisted into a suitable shape and placed in a housing.

The absorbent material in the filter is suitably elastic. In such a case, the material in the filter can be compressed, whereby the component absorbed from the gaseous substance flowing through the filter can be recovered.

The absorbent material in the filter suitably consists of polyethylene, polypropylene or a copolymer of polyethylene and methacrylic acid. Other features of the present invention will be apparent from the claims below.

2 77992

The absorbent material according to the invention is suitably made of polyethylene granulate mixed with small amounts of powdered additives to form bubbles. The mixture is fed to the first stage of a screw-type two-stage extruder and heated to about 200 ° C. The resulting melt is fed to a second press stage, where the temperature is lowered to 100 ° to 150 ° C, and the melt is pressed through an annular die. The resulting porous tube is air-cooled on the inside and outside and then cut lengthwise to obtain a strip of foam. Of course, parallelepiped-shaped pieces can be made instead of strips.

If parallelepiped-shaped pieces are made, it is most convenient to place them in the frame of the filter device. However, if a mat is used, it must be rolled up, shaped appropriately, and placed in a housing that is then placed in a filter device.

According to the invention, the carpet or parallelepiped-shaped pieces can also be broken up into small particles. The housing is then filled with these small particles and placed in a filter device.

The filter device of the type described above operates in the following manner. The gas containing the liquid droplets is passed through a filter device, whereby the absorption material collects the liquid droplets and, if the gas contains constituents which become liquid as the temperature decreases, the liquid thus formed is also absorbed. Once the filter device is saturated, the absorbent material is removed and replaced with new material. The absorbed material of the impregnated filter is then compressed so that the absorbed material can be recovered for reuse. After compression, the absorbent material is usable again. Thus, an absorbent material has been prepared which not only absorbs the liquid particles but also allows the recovery of these particles, whereby the material is again usable as a filter.

An endless strip can be made of the above-mentioned absorbent material mat. This strip is then allowed to pass over two rollers / one of which is Pull. The strip guided on the rollers is then placed in a filter device so that gas is allowed to flow through one strip section and then through the other strip section. The strip then absorbs liquid particles, which can be recovered if an additional roll is placed in connection with the second roll, which is pressed against the strip. Each part of the strip thus comes into contact with the gas containing the liquid particles at two different points, and the absorbed liquid is then squeezed out between the two cooperating cylinders.

Claims (5)

77992 A method for filtering a substantially gaseous substance, which gaseous substance may contain liquid particles or a gas which becomes liquid as the temperature decreases, characterized in that the gaseous substance is allowed to flow through a filter medium consisting of at least one elastic foam-plastic body with closed spaces the walls are routed, and that said gaseous substance is then separated from the liquid contained therein. A method according to claim 1, characterized in that the foam body can be compressed so that said closed, perforated spaces become completely or partially flattened or crunched. A method according to claim 1, characterized in that the foam body consists of polyethylene, polypropylene or a copolymer of polyethylene and methacrylic acid. Method according to one of the preceding claims, characterized in that the absorbent is compressed to remove the liquid absorbed therein. A method according to claim 4, characterized in that the absorbent material is compressed by passing the material between rollers.