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Happy owners of the country real estate, both comfortable cottages, and small country houses, cannot do without water supply system. Arrangement of the autonomous system allowing to pump water to the house and to use it for watering of the site becomes optimal variant for them. Contamination of the well which can be considered basic element of construction becomes frequent the serious problem requiring the urgent solution. That not to face it, it is necessary to install surely the filter on the well. And to service it and it is even possible to make independently.
Borehole filter: device and assignment
The filter is one of sites of the work area on upsetting column. Its task – to prevent hit of large particles of pollution in construction and at the same time freely to pass clear water in pipe. Additional function of design is protection of walls of the well against possible collapse. The part can be separated into three significant elements: actually the filter, over the filter site and settler where large parts of pollution collect.
Practice shows that purity of the water received from the well directly depends on the competent choice of the necessary type of the filter. The design is selected proceeding from characteristics of layer of water-bearing zone and depth of trunk. Besides such factors are surely considered:
- Resistance to corrosion in hostile environment.
- The mechanical strength expected serious axial stretching and lateral loads.
- The porosity expressing the relation of total area of all openings of the filter to the area of work area of part.
- The sizes of slots and cells which interfere with carrying out of the contaminating particles from water-bearing layer.
Proceeding from characteristics of layer, specialists recommend to choose filters as follows:
- For sand of small and average fineness – rod and tubular constructions from grid of galunny weaving.
- For gravel sands with grains to 10 mm – frame filters with slot-hole or perforated perforation and wire winding.
- For pebble, unstable and semi-rocky breeds with particles to 100 mm – perforated and slot-hole parts.
Besides, regardless of composition of water, it is the best of all to make the accompanying elements and framework of the filter of stainless steel. If there is no such opportunity, to use pipes of prospecting and oil ranges or pumping and compressor. They have bigger weight, but also will serve much longer.
Filters of this kind are considered as the simplest. They are pipes with the round openings drilled in them. Can be made of the asbotsement, cast iron, plastic, steel and even tree. Have rather good utilization properties. Can be used for installation in different water-bearing layers, but most often mount them in wells with unstable water-bearing layer and low pressure. The low cost and extreme simplicity in production are considered as the main advantages of perforated filters.
Independent production of construction requires pipe of diameter, suitable for the well. Material can be any, however, if it is plastic, it has to be safe for human body as it will adjoin to potable water. Depending on granulometric characteristics of breed of water-bearing stratum the necessary diameter of drill which will be used for perforation is selected.
We get to work:
- We carry out marking. We stack pipe on the suitable horizontal plane and we plan over the filter site and settler between which there will be filtering zone. It has to occupy not less than 25% of pipe length and after immersion to be located in the working site of the well intended for intake of water.
- We put perforation. For performance of the first opening at least 100 cm recede from edge of pipe usually. The interval between elements makes about 1-2 cm, it is the best of all to have them in chessboard order. It is the most correct to drill openings at an angle at 30-60 °, directing drill from below up. All keen edges it is necessary to smooth out, raise pipe and carefully to tap it that all shaving has been removed from openings.
- We close the lower part of pipe wooden stopper. For protection against contamination the part can be enveloped special grid.
Slot-hole elements are similar in the building to perforated. However instead of openings narrow slots through which water comes to column are applied on them. Such design is more preferable as it has high flow capacity due to lack of “deaf” zones and a hundred times the big area of slot in comparison with opening. The main lack of elements is considered smaller, than at other parts, flexural strength. At independent production of the slot-hole filter special “stiffening rings” — pipe sections without perforation are surely provided.
Independent production of such filter requires the pipe suitable on the diameter the well, cutting blowpipe or the Bulgarian depending on way which supposes to make openings. All works are performed on algorithm, similar to production of the perforated filter. The only distinction consists in form and size of openings. For slot-hole designs their width varies from 3 and up to 5 mm, and length – from 25 to 75 mm. At the same time cuts, both in chess, and in zone order are located. Over framework the grid, most often metal can be imposed.
It is very important to pick up grid correctly. The industry releases material of galunny or square weaving. All galunny grids have the special marking executed in the form of fraction. On it in numerator the quantity of delays in basis, and in denominator – the same size for duck in recalculation is specified square of 25х25 mm. Experience shows that the highest utilization properties at brass grid with galunny interlacing. One more nuance: for the work of the filter in the well performed in gravel breeds only the grid of square weaving is used.
To choose the size of openings it is the best of all to take several samples of different material and to sift through them dry sand from the site where the well will work. On average choose that sample which detains half of particles. However, if fine sand, stop on the material which has missed about 70%, and here for large fractions the option through which there pass about 25% will become acceptable. Thus, for exact selection of grid it is necessary to determine at first the sand size on the site. It is rather easy to make it, having poured out it on scaled paper. Having compared leaf cells to grains of sand, it is possible to draw conclusions. Small parts from 0.1 to 0.25 mm in size, – from 0.25 to 0.5 mm, respectively, large – from 0.5 to 1 mm are considered as average.
Having picked up grid it is necessary to establish correctly it on in advance prepared framework. At first on spiral step of 15-25 mm reel up qualitative corrosion-proof steel wire with a diameter of 3 mm on pipe. For durability it is pointwise soldered through everyone half-meter. Thus the basis is prepared. The grid is imposed with an overlap on framework and tightened wire which stack on spiral with step 50-100 mm. All rounds after they are twirled, combination pliers bend under tie. It is one way of fastening. There is also another when the grid is soldered to the prepared basis. At first one edge is fixed, later on it the second with an overlap is fixed.
The slot-hole filter which has turned out as a result with grid is among the best for use in the well on sand. It is considered that systems with grid have set of advantages:
- Simplicity of production.
- Opportunity to receive water from the friable layers which are characterized by the different size of sandy grains.
- Can be used at any depth of wells.
- Possibility of simple extraction on surface for carrying out repair.
Common faults of slot-hole and perforated filters with wire mesh guard from metal:
- Decrease in operational output, respectively, falls well productivity a little.
- Destruction of grid which is provoked by corrosive medium.
- Jamming of openings under the influence of fine-grained reservoir sand.
Wire filtering systems
The design represents perforated basis with the filtering framework and slime settler. Such construction is more long-lasting, than slot-hole and perforated parts with wire mesh guard as durability of the wire forming drainage course much higher. Flow capacity of such design depends on the section, step and form of wire. For construction durability in each point of contact of wire with framework it has to be taken by welding. It should be noted that independent production of the wire filter is very labor-consuming therefore it is considered almost impracticable task.
However fans to overcome difficulties can independently try to make such design. For framework the normal slot-hole filter without grid with width of openings, equal to the average diameter of particles of breed is carried out. Over it 10-12 iron rods with a diameter not less than 5 mm longwise keep within. The corrosion-proof wire of diameter of 2 – 2.5 mm under tension is cast over the prepared basis. It is the best of all to carry out this operation with the help of turning lathe, however it is possible and manually, but then the special accuracy and patience will be required.
Such filters are installed as in complex with mesh and wire, and separately. They are used in the wells drilled in the fine and mudded sands. The system is capable to delete the smallest parts of pollution which are not late the wire mesh filter from water. For arrangement of design the well bigger is drilled, than it was planned diameter. Gravel for the filter is carefully selected and calibrated as only the one-dimensional fraction is required. The size of gravel has to be at 5-10 times more the average size of parts of breed. The fraction is filled up to the well from the mouth, sprinkling thickness – at least 50 mm.
The principle of operation of such filter of mechanical cleaning is extremely simple: fine grains of sand get stuck in gravel dumping and over time are washed away by water in settler. Gravel systems are especially appreciated for:
- possibility of production of design for mechanical cleaning practically for any mountain cuts;
- low requirements to the used material;
- simplicity of installation works.
Are among the most significant shortcomings of filters from gravel:
- rather small water fascinating surface of system;
- complexity of preservation of filter layer during sprinkling;
- need of expansion of diameter of trunk.
Service of borehole filters
Sooner or later any filter fails. Muddy water and falling of its productivity of the well become the first signs of problems. The owner of system needs to know about the possible reasons of silting of design:
- Long breaks in use of construction. The operating pump does not allow small particles and oozy deposits to be besieged at the bottom of trunk. As soon as it stops, silt begins to be laid at the bottom of the well, gradually reducing distance between the bottom and receiving part of the pump. The longer the break, the longer lasts silt adjournment process. It will proceed until the pump does not tighten in thickness of rainfall. In this situation at turning on of the equipment it can just fail.
- Natural and technogenic pollution. Carry silt and sand which are washed away from layer of water-bearing zone to natural, and their quantity depends on soil type. Technogenic pollution which get to the soil together with irrigation waters and industrial drains also affect composition of water in the well. The closer to earth surface the water-bearing layer is located, the this influence is more.
- Defects of the well. One of them – low-quality waterproofing of annular cavity that gives the chance to surface run-offs to get to the well.
- Mistakes in the caisson device. Sand and dust from surface get to the well, accumulate on trunk walls, its day and the pump strainer, putting it out of action.
- Low-quality vibropumps which in the course of the work destroy the trunk walls unprotected by pipe. As a result on bottom of the well settles large amount of soil.
Becomes clear that periodic cleaning of the filter is necessary. Most often this operation together with cleaning of the well is carried out by the specialists invited by the owner, but it is possible to cope and independently. The first way consists in “blowing off” of trunk water. For this purpose on bottom the string of piping connected to capacity, high water plunges. Under big pressure water is pumped in trunk and washes away all outgrowths, silt and sand which come to surface. Pump over the well before emergence of clear water. Shortcomings of such washing consider need to use big capacity with water, most often for these purposes use specialized cars with tanks. Besides dirty water, literally, the fountain whipping on surface, also gives inconvenience.
The second way is less labor-consuming, but will demand certain monetary expenditure. The inexpensive vibration pump of the class “Gnome” is bought and temporarily is installed to the place of submersible. In the course of cleaning the pump is lifted and lowered on rope to shake up water in the well. Muddy liquid is pumped out until clear water seems. This way less productive, but does not demand the bulky equipment and does not contaminate surface around the well.
The well – basis for autonomous water supply system. Its maintenance in operating state, independent service and production of the filter, one of the most important elements of system, guarantees uninterrupted intake of clear water to the house.