Assembly instructions FV ENERGEO

For connecting of individual pipes, mainly electro pipe fittings are used, rarely mechanical clamp links. When using the electro pipe fittings, a completely homogeneous link arises, therefore in the system FV ENERGEO we use high-quality electro pipe fittings Georg Fisher.

The work must be carried out by workers with welding license for plastic welding. It is not possible to weld polyethylene with polypropylene, but at the same time we warn about mutual welding of pipes and pipe fittings from branched (LDPE, rPE) and linear polyethylene. Welding of these relatively hardly distinguishable materials (LDPE has thicker walls for the same pressure) cannot be by any meanscarried out in practice. If it is necessary to connect these two materials, in case of any doubt about the origin of particular pipes, you are better advised to use mechanical clamp links.

BACKBONE PIPEAGE

Connection of a distributor / collector with thermal pumps is carried out by means of backbone pipeage. Backbone pipeage is made by a polyethylene pipingof a higher diameter FV ENERGEO HDPE or FV ENERGEO HDPE-RC. The diameter o f the piping is determined according to its length and a flow rate of the antifreeze liquid. It is necessary to lay the backbone pipeage of the HDPE pipes in the sand bed.

INSULATION OF A PRIMARY CIRCUIT

All kinds of pipes, be it backbone pipeage or piping leading directly to the wells in the case of the surface collector, need to be insulated, beginning at 2 m away
from the object. All pipes inside the object also need to be insulated, so as to avoid potential water condensation at the distributions. It is only possible to insulate the primary circuit with a suitable rubber insulation, not with an insulation of the PE material and the like. It is necessary to protect the piping insulated by a rubber insulation outside the object by a cable duct and provide it with a gasket preventing the water intrusion into the gasket. Principles of correct instalation of ground surface collectors:

REDUCTION IN THE NUMBER OF BRANCHES (Y-PIECE)

Y-piece is a special pipe fitting for associating of two circuit geothermal ground probes in one circuit (32-32-40, or 40-40-50). By their use the number of connecting pipings leading from the well to the system of the distributor / collector and also the number of the outputs of the distributor / collector itself is reduced. Y-piece CANNOT be replaced by a classical T-piece because of the prevention of a strong pressure loss in the whole system! When using the reduction it isnecessary to abide by an even division of the flow of the liquid into both loops of the g eothermal well.

Principles of correct implementation of geothermal wells:

LAYING OF A SAND BED

Laying in an open excavation, where sand is used for underlaying and surrounding of the piping, is one of the oldest ways of layings for PE piping. If we did not lay the older types of PE pipings (PE63, PE80 and PE100) which do not possess improved resistance to mechanical stress in sand, their expected lifespan would reduced more than five times. Thanks to the sand underlaying and surrounding, which protects the piping, this method of laying is one of the laying methods with a low risk of damage.

LAYING

In the case of the piping from HDPE-RC, its laying and backfill can be carried out without the sand bed, using the directly excavated soil including the aggregate up to 200mm. In the case of HDPE pipings it is necessary to respect the character of the bedrock. If the piping route occurs in areas with soils of the minability class
I.to IV. (according to CSN736133:2010), we can also use the directly excavated soil for the laying. An exact determination of the minability class can only be determined by a geological research, that is usually a part of each project preparation. Earthwork during the piping laying must not influence its ovality. Material
for surrounding and backfill need to be compactable enough. Piping is laid onto the even and paved bottom of a groove. The surrounding is carried out layer by layer and is compacted. If the route of the piping is located in areas with soils of the minability classes of V. to VII. or where the occurrance of these soils cannot be disproved, it is necessary to duly lay the piping in a sand bed.

CONNECTING

For connecting of individual pipings, mainly electro pipe fittings, and rarely mechanical clamp links are used. When electro pipe fittings are used, a completely
homogenious link arises, therefore in the FV ENERGEO system we use high-quality electro pipe fittings Georg Fisher.  

WELDING

For connecting the FV ENERGEO HDPE and HDPE-RC pipes with pipe fittings or butt welding can be used, polyfusion or with the use of electro pipe fittings
which we recommend for the FV ENERGEO system. Apart from a problem-free connecting right in the field, electro pipe fittings also enable assembling of the
whole piping thanks to integrated clamps. Welding work must be carried out by workers with welding licence for plastic
welding. It is unacceptable to weld polyethylene with polypropylene and to weld pipings and pipe fittings of branched (LDPE, rPE) and linear (HDPE, HDPE-RC) polyethylene. If it is necessary to connect these two materials, mechanical clamp links must be used. The most important operations for achieving a high-quality weld are:

Be careful about welding at low temperatures – allowed minimum temperatures at which welding is still possible, are determined by the properties of welding machines or electro pipe fittings. In the strong wind, in the case of butt welding or polyfusion welding, it is necessary to check not only the right temperature settings of the welding agents, but also the actual agent temperature. Welding temperature for PE butt welding is 200–220°C, for polyfusion welding 250–270°C. It is important to comply with the time course of particular operations including the time for weld cooling, during which the weld cannot be burdened mechanically. In this context we refer to the instructions of the manufacturers of particular welding devices and primarily to the compulsory trainings.

MECHANICAL CONNECTING

Mechanical clamp links enable connecting of combinations of different materials
and also enable the use of slightly oval pipings which can be formed by pipe
fittings. Links can be metal or plastic. When carried out properly, the link has
the same or higher breaking strain than the connected piping itself. Connecting
using flanges (edge bearers).

MANIPULATION WITH THE PIPING, MECHANICAL STRAIN AND CHANGE IN THE DIRECTION OF THE PIPING (BENDING)

It is not allowed to carry out heat shaping of the pipes at the construction site. However, PE elasticity allows for a change of direction or copying the terrain by producing arcs with a diameter R, which should be, according to the temperature (independently of the piping pressure line):

• 20°C.....20 x D
• 10°C .....35 x D
• 0°C.......50 x D

where D is the outer piping diameter. A properly carried out excavation can therefore mean savings of the material and time. For more significant changes in the direction, particular pipe fittings need to be used.Spools with pipings must be protected against mechanical damage. In a case of visible damage of the outer layer (its cutting or rubbing) it is necessary to cut  out the particular piping and connect the ends with a suitable pipe fitting. Pipes can only be unwinded the opposite way than they have been winded during their production. Spiral unwinding, when the wall of the piping is strained torsionally and when there is a danger of „breaking“ the piping, is strictly forbidden. Fittings and cast iron pipe fittings need to be built in in such a way that their own mass or forces needed for their operation would not produce forces that were not taken into account when designing. We recommend fixing the fittings by a „firm point“, e.g. using a concrete block and so on.