HDPE casing for threaded wells. Features and properties
Water supply in private homes or cottages is often organized through wells or boreholes. Casing pipes are used for proper operation of such sources, through which water will enter the home pipeline. Casing structures are required for this, so that the soil in the well does not crumble and does not get into the system. HDPE casing for threaded wells is the best option for these purposes.
The use of threaded pipes greatly simplifies the work of casing wells and guarantees a reliable connection.
How to choose a pipe for casing? Advantages of HDPE casing
In addition to plastic materials, metal and asbestos cement are used in the production of casing. These types of products have significant disadvantages, therefore low pressure polyethylene (PND) now used almost everywhere. HDPE casing pipes for threaded wells have many advantages:
- light weight, cheapness and ease of transportation;
- threaded connection allows installation without special tools;
- plastic does not emit harmful substances and does not change the composition of the fluid passing through the system;
- dense structure of the material, which is not subject to corrosion, provides strength to products.
Also, HDPE casing pipes have the ability to adjust the length of the system by building additional modules. Threaded connections ensure complete tightness, at the same time, that the load on the joints will be minimal. If the pipeline section is damaged, the segment can be easily replaced, quickly and without much expense.
Steel pipes are the best option for cladding, but if the well is not deep, then they will be successfully replaced by polyethylene products
HDPE pipes can perform their functions in the temperature range from -70 to +80 degrees. That is especially important, that the plastic structure is not affected by low temperatures, which predominate in soil sources.
The main disadvantages of plastic casing
The disadvantage of HDPE pipes is, that such structures are not flexible enough and strong in bending. This fact should be taken into account during installation: the product must be placed in an evenly drilled well, without soil protrusions and thresholds.
Wrinkle! Sometimes steel products are used to insert the pipe into the well, followed by replacement with HDPE casing. This will eliminate damage to the plastic structure.
Polyethylene pipes are suitable for casing wells, the depth of which does not exceed 100 m. For deeper wells it is better to use metal structures, as HDPE may not withstand such pressure.
If you have to drill a well in rocky soil, it is also desirable to use steel pipes. Systems in limestone soils function better when lined with asbestos-cement pipes. HDPE pipes for threaded wells are excellent mainly for clay and sandy soil types.
The use of plastic pipes when lining wells
The diameter and wall thickness of HDPE casing for threaded wells will depend on the depth, on which the aquifer will be located.
The deeper the well, the greater the diameter and thickness of the walls of the casing
Water can be located close to the soil surface (riding layer), in the soil layer and at high depths 40-250 meters (artesian water). Water in the top layer, usually, going from precipitation, dropped out. It is not suitable for drinking and is used only for economic purposes. Groundwater undergoes a significant degree of purification through the passage of layers of sand and clay. Such wells are most often drilled in adjacent and country plots due to the availability of works and high quality of the received water..
Polyethylene pipes are successfully used in all cases. HDPE casing for threaded wells for groundwater supply systems will have a diameter of 125 mm. Products with this diameter are able to optimize the system without increasing the cost of drilling a wide well.
Wrinkle! At great depths, the device may be telescopic, when the diameter of each lower segment will be different from the upper on 50 mm.
To immerse the column below, than on 10 m, it is better not to use casings with a wall thickness less 8 mm. For well devices with a depth of 50 m required thick-walled HDPE pipes with a wall thickness of 10 mm.
Materials for insulation of HDPE pipes
The question of well insulation should be asked before its arrangement. For better functioning of the system in the cold season, it is necessary to insulate the well surface, and HDPE casing for threaded wells or without, and water supply to the house.
Mineral wool is one of the simplest and most affordable materials, which can insulate the well
The choice of insulation for polyethylene pipes should be based on climatic conditions. If the depth of soil freezing exceeds 1,5 meters, which is typical of the northern regions, apply comprehensive measures to isolate the system. Insulation of HDPE pipes underground is carried out with mineral wool or roofing material. Pipes, located on top of the ground, insulated with the same materials, but with the use of construction foil as protection against precipitation. More expensive, but an effective method of insulating underground structures is a heating cable.
To supply water from the well, you can buy a ready-made insulated HDPE pipe. It fits into the ground on a sand cushion. In general, installation of pipes with warming does not differ from laying of usual HDPE products. If you want to connect an ordinary HDPE pipe with an insulated one, adapters are used.
The order of work on well insulation
The wellhead can be equipped with a plastic caisson or an insulated box, if the climate in the region is mild enough. For insulation, a trench is dug to a depth 1-1,5 m (depending on the depth of soil freezing). You can place the necessary equipment in the box: pumping station or expansion tank. The depth of the pit for the caisson will be at least 2 m.
Caisson will help protect the well not only from frost, but also from the ingress of groundwater into the pipe
Wrinkle! There is a high probability of water freezing in the systems, which are used irregularly. Even if winter temperatures in the region do not fall below -15 degrees, but the well works only in summer, it is better to equip high-quality insulation. This will reduce the risk of system failure.
After laying the trench, the wellhead is cut to floor level of the box. The floor of the box is arranged with a lid, which is made according to the diameter of the applied pipe. You can use ready-made insulation covers for wells or make it with your own hands from wood (metal) and apply the material.
HDPE casing for threaded wells is recommended to be wrapped in plastic or metal material. To better retain heat, leave a distance between the pipe and the insulating layer 5 cm. The air gap will be an additional protection against freezing. The air layer can also be filled with sawdust.
At very low winter temperatures in the immediate vicinity of the well install electronic heaters. Casing and water pipes rotate with wires, heated from the mains. Heating wires should be stretched in plastic corrugated pipes, to prevent network short circuits. Box, in which the heater will be located, should be well ventilated.
With the right choice of casing type and method of insulation, the plumbing system will last a long time and quality. Drilling at great depths should be carried out by specialized organizations, as at the admitted technological error can reduce to zero all results of works. And re-drilling in the same place is impossible.
