FR2537697A1 - Method for insulating and protecting buried hot-water and steam pipes. - Google Patents

Abstract

It is a specific method for buried pipes which resolves, at the same time, surface protection and thermal insulation. The pipes 1, 2 are embedded in dry pozzuolana 3 and without air. An external envelope 4 made from plastic ensures leaktightness.

Description

 The high price of petroleum thermal energy favors the development of the supply of hot water and steam from nuclear power plants and coal-fired power plants. This results in the creation of many heat transport circuits and to avoid significant losses and ensure good preservation of the pipes 9 their coating and insulation must be particularly effective. Currently, there are no really valid solutions; paints and bitumens do not hold well, due to the high temperature of the tubes. As for insulation by glass wool and metal protection, it is an expensive process and difficult to apply to buried pipes.

 te process, subject of this patent, is a specific process of buried pipe, it resolves at the same time the protection and insulation of pipes, and its price is relatively low.

Description
According to the attached sheet, the top figure, on the left, is a section of the pipes once installed. (I) is the supply pipe for hot water (2) the return pipe, (3) for the dry airless pousolane, (4) a waterproof plastic envelope and (5) the earth for filling the trench .

 The pouzolane, which completely envelops the pipes, provides very good thermal insulation. your distance between the tubes and the quantity of pouzolane per meter are calculated so as to ensure optimum loss, taking into account the price of the pouzolane and the plastic envelope, very effective materials for their specific desired function, and the purchase price the lowest, compared to materials with similar functions.

 Regarding surface protection, the nature of the pouzolane surrounding the pipes - practically inert, dry and airless material - makes corrosion practically impossible and these pipes always remain in the state they were in at the time of their installation .

Implementation
According to the attached sheet, the top figure, on the right, is a section of the pipes being installed. At the time of the execution of the trench, a layer of earthenware without stones is left at the bottom. The plastic envelope (7) is placed while keeping its edges pressed against the walls of the trench, by means of points inserted very close to the outer edge of the envelope.
The nature and thickness of the plastic are chosen according to the loads to be supported.

 A first layer of pouzolanA8) is placed at the bottom of the trench.

 This material, in the divided state, with a maximum particle size of about 50, is dried on site, close to its use.

 The pipes are then prepared, welded above the trench, then lowered onto the layer (8). Place the cuckold (9) and proceed to close the envelope; by gluing, welding or zipper.

The elimination of air is done, before backfilling, in the following way:
According to the annexed plate, the figure below is a top view of the trench, after closing the envelope.

 We start to backfill in (9), over-about 2 bare and about all the IO M. Cn connects in (IO) a vacuum pump, so as to eliminate the air in the envelope, between 2 backfills.

 We can then proceed to complete and final backfilling of the trench.

Claims (4)

 REV3NDICAEICNE  hot water or steam, buried. I) New process for insulating and protecting pipes 2) Method according to Claim I, characterized by the use  dry, airless pouzolane surrounding the lines and  at the same time ensuring thermal insulation and protection  of surface. 3) Method according to Claim 2 using to isolate the  pouzolane, a hermetically sealed plastic envelope. 4) Process according to Claim 2, characterized by the creation  vacuum in the plastic envelope, using  partial backfilling, between which a pump is operated  empty.