【 Weak current College 】 heating pipes for underground laying of the way in several comparative material pipe fittings

With the new household metering applications, to family beautiful fashion, home heating pipe buried into fashion. The layout of the ground laying in the underlying layer, gradually become mainstream in layout mode.
Layout in ground underlying layer in the pipeline, whether used for next level with double pipe, pipe-line single-span or radiation double tube (or Octopus-like) way of piping, requires pipeline have longer life, lower layer thickness and relatively simple installation method, and avoid cushion inside connection tube, it would not be appropriate for the use of steel pipe, you can only use plastic pipes.

Another on the ground laying pipes within the cushions is radiant floor heating. Low-temperature radiant floor heating way more reasonable indoor temperature distribution and equivalent heat effect, not only traditional radiator convection heating way better comfort, but also can save energy by about 10%. Compared to cast iron radiators or other heat sink with cover old heating facilities, radiant floor heating can adapt to living persons for architectural decoration. In addition, also due to the need in the floor base lay insulation, can be part of reducing household heat metering at the household and the amount of heat transfer between households, and improves the sound insulation of floors and the lower impact sound. And low-temperature radiant floor heating heating pipe, plastic pipes should be used.

Currently suitable for conveying plastic pipes for hot medium, relatively reliable has the following four:

(1) xpap. Inner and outer as > 0.94g/cm3 density polythene or ethylene copolymer, middle-tier to reinforced aluminum tubes and layer with melts the cellophane closely bonded as one of the pipes. Used for the transportation of hot water, and external layer should be cross-linked polyethylene, called xpap, usually to XPAP tags.

(2) polybutylene pipes. By polybutene-1 resin adding just the right amount of additives, the extrusion thermoplastic pipes, called polybutylene pipes, usually to PB tags.

(3) cross-linked polyethylene pipe. To > 0.94g/cm3 density polythene or ethylene copolymer, adding just the right amount of additives, through chemical or physical methods, so that its pattern of macromolecular three-dimensional cross-linked into mesh of macromolecular structure, this kind of material tube, called a cross-linked polyethylene pipe, usually to PE-X tags.

(4) irregualr gathers tube. To alkene and just the right amount of ethylene copolymer, adding just the right amount of additives, the extrusion thermoplastic pipes, called copolymer tube, usually to PP-R tags.

Available from the following several aspects the comparison of the various types of pipe.

(1) the permissible stress of the sort. In the same conditions of use of Poles and effective service life conditions, various types of pipe of permissible stress, generally in the following order: xpap, polybutylene pipes, PVC pipes, copolymer tube.

(2) according to the market price of the order, the order is large. Not necessarily choose the permissible stress of the tubing, such as: actual service life of 50 years is not required or use temperature is low, or low working pressure, it is possible to select the allowable design stress smaller pipe.

(3) key or various types of pipe of effective quality control. According to the plastics industry professional analysis, polybutylene pipes and copolymer tube quality, mainly through the raw materials of composition and quality control. And cross-linked polyethylene pipe and xpap, in addition to the raw material composition and quality, the cross-linking process is essential for quality control, it is crosslinked process this important link, the quality of many such pipes.

(4) polybutylene pipes and copolymer tube, is a renewable raw material, more favourable to the environment. The two tubes can also be received by hot-melt, the connection process, saving costly connection accessories.

(5) the oxygen permeable material, should be considered, and other heating systems share the same centralized heat source water systems and other heating system using steel radiator etc corrosive components, polybutylene pipes, cross-linked polyethylene pipe and copolymer tube, oxygen layer should be deterrent to effectively prevent the penetration of oxygen and accelerate the oxidation and corrosion of the system. While xpap middle-tier to reinforced aluminum tube, effectively blocking oxygen permeability.

(6) vertical line expansion pipe, for heat pipe should be noted. Linear thermal expansion coefficient of steel tubes as 0.012mm/m? K, plastic pipes linear expansion coefficient of approximate value, from small to large arranged as follows:
Xpap 0.025 polybutylene pipes 0.130 copolymer tube 0.180 cross-linked polyethylene pipe 0.200
Due to the large vertical expansion, after the pipe heat deformation, and therefore not suitable for serious tomorrow. But buried in concrete cushion inside the pipe vertical expansion restricted, will translate into internal stress, it takes the strength calculation of safety coefficients with just the right amount.

(7) the low temperature performance issues, copolymer tube-environmental conditions that occur at low temperature embrittlement, easily damaged during transport, while the other pipe of brittleness temperature, can be as low as-70 ℃.

You can see from the comparison of no tubing is perfect. Therefore, should be based on the works of durable life requirements, using the condition rating, htm temperature and pressure, water quality requirements, materials supply conditions, construction and technical conditions and investment costs and other factors, the comprehensive comparative reasonable choice of pipe material.