Liquid separator

The invention relates to a liquid separator generally for the separation of the components of a liquid mixture having two components of different density, especially for filtering oil-type contamination from water, e.g.: precipitation water, exceeding many times its own quantity, especially for trapping oil on the surface of trace-line engineering structures such as railway tracks or road pavements mixed with precipitation water, and by this preventing watercourses or public channels receiving precipitation water being contaminated with oil. The liquid separator is built in the way of the precipitation moving towards the receiving watercourse or public channel, generally in a drain hole. The liquid separator has a reception side suitable for letting in the contaminated mixture, an internal unit with a replaceable filter, favourably oleophilic and hydrophobic, suitable for separation, and an outlet side suitable for letting out clean water. The liquid separator also has a carrying handle suitable for its installation and removal as a whole unit and a handling grip suitable for the temporary removal of the contamination trap. On the reception side of the liquid separator there is a water-collecting tray for catching the contaminated mixture and guiding it inside the separator.

Water gets contaminated with grease, oil and generally with hydrocarbons at numerous places. Due to the environment damaging effect of such water the soil must be protected from the contamination they cause. Contamination derives from two main sources: from industrial activity and from the "natural environment". The latter source involves liquid mixtures formed by oil getting on the surface of railway tracks and roads and by precipitation water.

Generally in these cases the quantity of the precipitation water is many times more than the quantity of the oil, but they need to be separated from each other by all means to prevent the contaminated mixture from entering the public channel or - which is even worse - directly a living watercourse. During the last century numerous ideas have occurred relating to the removal of oil from industrial wastewater.

The majority of known separators were created in the United States of America. Such so- called oil separators are described in the earliest patent descriptions no. US 745.519, US 925.834, US 995.521 and 1,032.458. Development has been uninterrupted ever since then, all the way until the solutions described in patent descriptions no. US 3,933.654, US 4,132.645, US 4,422.931, US 4,938.878, US 4,980.070 and US 5,348.648 in recent decades. Having different structural constructions these solutions all utilise the different density of the two liquids.

Besides industrial oil separators, the type of environmental damage caused by the mixture of hydrocarbon derivatives getting on the surface of trace-line engineering structures and precipitation water was realised at a much later point. One of the first engineering structures suitable for the highly efficient separation of such oil contamination based on a simple and creative principle is described in patent description no. HU 209.763.

Its advantage is that is able to operate for an unlimited period in time, without any machine equipment, wearing parts or human control, which is realised with the appropriate geometrical positioning of overfall crests. Its only disadvantage is that the engineering structures to be constructed, in which the contaminated mixture is separated, are specially constructed basins, and a large number of such basins is needed along trace-line engineering structures.

The so-called oil battery described in patent description no. US 5,236.585 has become known recently. It is also suitable for being constructed as a drain hole next to a trace-line engineering structure or paired with a drain hole. It utilises the difference in density combined with a filter made of foam. Its disadvantage is that the gradual separation of the mixture in several phases takes place in an apparatus consisting of several chambers, having a complicated structure and requiring frequent human interventions.

The solution known in the special field as "catch basin filter" described in patent description no. HU 2904 U is also suitable for use with drain holes, it reduces the oil content of precipitation water getting on the road. Inside the drain holes situated along the road a filter with oleophilic and hydrophobic features is inserted between two perforated cylinders. After passing the filter the precipitation water with reduced oil content flows on driven by gravitation into the ditch running along the edges of the trace-line engineering structure.

In principle the idea is right and simple. However, its disadvantage is that in disaster situations (e.g.: when a tanker lorry turns over), when a large amount of oil gets onto the road surface, it cannot perform its task any longer. It cannot perform its task in the case of an extraordinary amount of precipitation either, because the larger proportion of the contaminated mixture avoids the filter placed in the drain holes and overflows above the filter.

A common deficiency of the separators of the known structural construction is that, on the one part, due to their structural construction itself and, on the other part, due to the nature of the filters used the water to be cleaned is unable to enter the filter, instead it remains on its surface. Therefore, it gets impregnated quickly, and it is unable to trap the contamination arriving after this point. For this reason, the filtering efficiency cannot be improved by increasing the extent of the filter (e.g.: its thickness).

The aim of the invention is to develop a liquid separator that can be installed in drain holes situated along trace-line engineering structures, where it is suitable for trapping hydrocarbons - generally oils and oil derivatives - mixed with precipitation water, with a simple construction and economically. Furthermore, the task of the invention is to remove oil from contaminated precipitation water permanently and with appropriate efficiency, therefore it should not contain parts liable to fail.

The idea behind the invention is based on the recognition that if the tool to be built in the drain hole - having an internal structure different than the known ones - is constructed with a filter area surrounded with a double wall, and the internal wall is constructed as a so-called submerging wall and the external wall is constructed as an overfall wall, then the task can be solved.

It also forms part of the recognition that the double wall surrounding the filter area is suitable for reducing the flow-rate of the water, as a result of which the water is forced to spend more time inside the tool, which increases the efficiency of cleaning. It is also favourable to construct an area below the filter area suitable for catching any solid matter.

In accordance with the set aim the liquid separator generally for the separation of the components of a liquid mixture having two components of different density, especially for filtering oil-type contamination from water, e.g.: precipitation water, exceeding many times

its own quantity, especially for trapping oil on the surface of trace-line engineering structures such as railway tracks or road pavements mixed with precipitation water, and by this preventing watercourses or public channels receiving precipitation water being contaminated with oil -, which liquid separator is built in the way of the precipitation moving towards the receiving watercourse or public channel, generally in a drain hole, the liquid separator has a reception side suitable for letting in the contaminated mixture, an internal unit with a replaceable filter, favourably oleophilic and hydrophobic, suitable for separation, and an outlet side suitable for letting out clean water, the liquid separator also has a carrying handle suitable for its installation and removal as a whole unit and a handling grip suitable for the temporary removal of the internal unit trapping contamination, on the reception side of the liquid separator there is a water-collecting tray for catching the contaminated mixture and guiding it inside the separator -, constructed in such a way that the liquid separator has a house, which is open at the top and delimited by a base plate at the bottom, the inside of the house is formed by a filter area also suitable for trapping sludge, the house has a double wall, the internal, so-called submerging wall of which surrounds the filter area, the submerging wall is surrounded by the external, so-called overfall wall leaving a drift space, at the deepest part of the house there is one or more transfer holes letting the water into the drift space after it has passed through the filter area, on the surface of the overfall wall there are overfall holes suitable for letting out the cleaned water flowing upwards from the direction of the one or more transfer holes, and there is a box for trapping any solid matter inserted between the filter area and the base plate.

A further feature of the liquid separator according to the invention may be that on the upper part of the submerging wall there are overflow holes allowing a part of the arriving water quantity to avoid the submerging wall and also the filter area at the same time, in the case of possible hydraulic overload. The filter, favourably having oleophilic and hydrophobic characteristics, suitable for increasing the efficiency of trapping oil is placed inside the filter area.

In the case of a favourable construction of the liquid separator the filter fits onto the side of the internal grid to be placed inside the filter area facing the submerging wall, and it is fixed to the internal grid with braces.

The internal grid is formed by longitudinal rods and cross members crossing them. In a possible case they form separate rings situated above each other, while in another case they form one single continuous spiral.

According to another favourable construction the handling grip is attached to the internal grid and to the guide flange covering it at the top. Similarly the carrying handle is connected to the water-collecting tray and is favourably fixed to it.

The water-collecting tray surrounds the submerging wall and overfall wall of the house like a collar and is fixed to them. There is sealing inserted between the submerging wall and the guide flange and the water-collecting tray. At the lower part of the house there is a collar surrounding the filter, which collar is sitting on the box for trapping any solid matter in such a way that sealing is inserted between them. The braces are fixed with brace-fixing pieces.

As compared to other known structures built in drain holes used for a similar purpose, the liquid separator according to the invention has numerous advantageous features. The advantages are due to the structural construction. The main advantage is that beside minimal maintenance it is able to "filter out" oil-type contaminations from precipitation water for a long time and at a greater efficiency than before, and to protect watercourses and public channels receiving precipitation water from substances damaging the environment.

Another advantage is that due to the method of installation used it is not sensitive to the effects of the weather, it is able to retain any solid matter, no supervision is needed for its operation, and due to its structural construction its installation is quick, simple and cheap.

Below the invention is described in greater detail in connection with a construction example, on the basis of drawings. In the attached drawings

figure 1 is the lateral view of the liquid separator according to the invention, figure 2 is the top view of the liquid separator according to the invention, figure 3 is the vertical section taken along plane III-III shown in figure 1 , figure 4 is the axonometric view of the liquid separator, figure 5 shows the internal grid supporting the filter from inside, figure 6 is the vertical section taken along plane VI-VI shown in figure 5,

figure 7 is the axonometric view of the internal grid, figure 8 is the axonometric view of the filter fastened with braces.

Figure 1 shows the lateral view of the cylindrical house 1 of the liquid separator. At the bottom the house 1 is delimited by a base plate 11, it is open at the top, and a water-collecting tray 6 also open in the middle is attached to it. In figure 2 the inside of the house 1 can be seen from the top, at the bottom of the house 1 there is a box 8 for trapping any solid matter, while on the upper part of the house 1 there is a water-guide flange 22 positioned at a height shown in figure 3.

On the overfall wall 10 forming the external cylindrical surface of the house 1 there are overfall holes 12 around a circle, through which the water can leave the liquid separator after it has been cleaned in the filter area 14 inside the house 1. Figure 2 also shows the carrying handle 7, which is attached to the water-collecting tray 6, and with the help of which the whole of the liquid separator can be placed inside the drain hole not shown in the figures so far.

Figure 2 also shows the handling grip 4, which is used when the filter 2 shown in figure 3 with a "honeycomb structure" needs to be removed from and returned into the separator for regeneration. For this reason the handling grip 4 is fixed to the grid 17 supporting the filter 2 from inside.

In figure 3 it can be seen that the filter area 14 situated above the box 8 for trapping any solid matter at the bottom of the house 1 is surrounded coaxially by the submerging wall 9 situated closer to it and by the overfall wall 10 situated further away from it.

The pathway of the water-flow is also shown in figure 3. The contaminated precipitation water arrives in the separator from the top, from the direction shown by arrow 20a, it passes through the filter 2 situated inside the filter are 14, "leaves behind" the contamination along the material of the filter 2, makes its way towards the transfer hole 16 at the bottom of the house 1 in the direction shown by arrow 20b driven by gravitation, flows around the submerging wall 9 in the direction shown by arrow 20, and enters the drift space 15. Here it rises upwards all the way until it flows over the overfall wall 10 through the overfall holes 12 in the direction shown by arrows 2Od, and leaves the house 1.

The overflow holes 13 are shown both in figure 3 and 4, they prevent any excess water that the filter area 14 is unable to receive in the case of excessively large hydraulic loading from leaving the house 1 avoiding the filter area 14.

Figure 3 also shows the sealing 5 situated between the water-guide flange 22 and the submerging wall 9, and also the sealing 18 situated between the upper rim of the box 8 for trapping any solid material and the collar 19 at the bottom of the filter area 14 accommodating the filter 2.

In figures 5, 6 and 7 the internal grid 17 can be seen with the filter 2 removed, it is formed by longitudinal rods 17a and cross members 17b together. According to figure 5 and 6 the cross members 17b are separate rings, but they can only be constructed in the form of one single continuous spiral as shown in figure 7.

Figure 8 shows the replaceable internal unit of the liquid separator on a larger scale than before. Here the filter 2 can be seen too, which is supported by the internal grid 17 from inside, which cannot be seen as it is covered by the filter 2. External support is ensured by two braces 3 forming flexible bands on the filter 2. The ends of the braces 3 are joined together by clips 23, and the braces 3 and the clips 23 together are fixed to the surface of the filter 2 by a fastening member 21 for example with a T cross-section.

Figure 8 also shows the collar 19 surrounding the bottom of the filter 2, the sealing 18 below the collar 19, and the water-guide flange 22 attached to the internal grid 17. It is also shown here that the filter 2, its internal and external supports and the water-guide flange 22 together form one single fitting unit fixed together, which unit can be removed in one piece from the liquid separator using the handling grip 4, and it can also be returned into the liquid separator after the replacement or regeneration of the filter 2.

The tool according to the invention can be used favourably in "point-type" drain holes situated along trace-line engineering structures, mainly bridges and roads, where it is able to separate floating, setting material from precipitation water falling on a surface of hundreds of square metres, and to retain floated contamination.

Its significance is increased by the fact that its installation is quick, simple and cheap, its investment costs are low, and the favourably coalescent filtering medium forming the filter needs to be replaced less frequently than in the case of ordinary filters.