CS255935B1 - Method of pipe coupling,particularly for glass reinforced plastic pressure pipes - Google Patents

Abstract

A method of joining pipes, in particular fiberglass winding pressure piping it proceeds so that the pressure ends pipe is placed in gap against each other and k the connection point from the outside of the pipe attach a rigid sleeve whose inner diameter is larger than the outside diameter of the pipe. The end of the gap between the rigid sleeve and the outer side of the pipe is blinded and k the inner surface of the pipe at the point of contact the pipe will seal. Do like this the resulting connection space is introduced potting sealant. The way of connecting pipes is usable in different fields and areas economy where it needs to be linked fiberglass coiled pressure piping.

Description

BACKGROUND OF THE INVENTION The present invention relates to a method for connecting pipes, in particular fiberglass winding pressure pipes for diameters greater than 400 mm, for conveying liquid aggressive media to a maximum pressure of 0.4 MPa, which is composed of individual fiberglass winding pressure pipes connected by pressure joints.

The prior art fiberglass pressure pipes made up of fiberglass pressure pipes made by winding, spraying, extrusion, hand laminating or a combination of these technologies have pressurized joints in several ways. These are rigid or sliding pressure joints.

The most commonly used rigid pressure joint is a flange with a fixed or union flange. These joints are similar to metal pipes. In fiberglass winding pressure pipes, said joints are made of metallic or non-metallic materials. *

When conducting aggressive media, metal joints require metal materials that resist aggressive media.

In this case, however, there are high production costs for pipeline construction.

If non-metallic materials that are resistant to aggressive media such as plastics are used, the viscoelastic behavior of the plastics results in relaxation of the initial preload of the screws over time. For permanent tightness of the joints it is necessary to tighten the screws periodically.

Another type of rigid pressure joint is its overlaminating when mounted on site. This method is very laborious due to the manual lamination technology. The joint must be easily accessible and laminating work must be carried out in warm, dry weather.

The rigid joint, including the overlaminated joint, does not allow free thermal expansion of the individual pipes. This results in relatively high sheath stresses.

A typical example of a sliding pressure joint is a socket joint. The tubes are provided with a neck on one end and a cylindrical surface on the other. The pipe end is inserted into the neck of the second pipe. The neck joint is sealed with an o-ring or several o-rings. In some types of neck joints, various shapes of gaskets made of rubber or other resilient materials, such as a labyrinth rubber seal, are used.

This type of pressure joint allows thermal expansion of the pipes and assembly of the route is simple. The condition of good sealing effect is perfect roundness of the tubes and smoothness of the cylindrical contact surfaces of the tube parts. It is the inner cylindrical surface on the throat side and the outer cylindrical surface on the cylindrical end of the pipe.

In the case of fiberglass winding tubes, a smooth surface is produced on the inside of the tube, since winding is performed on a smooth mandrel, and on the outside of the tube a rough irregular surface. Accordingly, it is necessary to carry out a post-treatment of the outer surface at the joint to ensure the tightness of the pressure joint. However, this entails considerable production costs.

Furthermore, it is difficult to ensure circularity in the production of these fiberglass winding pressure pipes and to maintain it during storage, transport and assembly.

- 3 Therefore, it is very difficult to build a fiberglass winding pressure pipe with socket connections while ensuring perfect tightness against leakage, especially aggressive media.

These drawbacks are overcome by the method of connecting the pipes, in particular the fiberglass winding pressure pipes according to the invention. Its principle consists in placing the ends of the pressure pipe with a gap facing each other, with a rigid sleeve with an inner diameter greater than the outer diameter of the pipe from the outside of the pipe. a sealing is applied to the inner surface of the pipeline at the point of contact of the pipeline and a sealing curing compound is introduced into the connecting space thus formed.

The pipe connection method according to the invention ensures perfect tightness against leakage, especially aggressive media. The method also makes it possible to use pipes with an untreated surface of the pipe ends and permits considerable dilatations from the temperature without compromising the tightness of the pressure joint.

BRIEF DESCRIPTION OF THE DRAWINGS The invention and its effects are explained in more detail in the accompanying drawing, in which: Fig. 1 shows a cross-sectional side view and Fig. 2 shows a side sectional view of a pipe connection; invention.

The individual fiberglass winding tubes 2 are connected by a mounted concrete sleeve. The concrete sleeve is divided and consists of three pieces. A space 1 is formed between the concrete sleeve and the pipe ends, which is closed on both sides by sealing rings 4. On the inside, the gap between the tubes is closed with adhesive tape 6 and sealed with a rubber pressure bag. A rubber pressure bag presses the adhesive tape to completely close the space 1. In this ring-shaped enclosure, the sealing sealant is introduced through the pouring opening 6. In order to fill the space perfectly without leaving an air bubble there is a vent hole 7 in the air bubble. ·

The sealing sealant, polyurethane elastomer, has the following composition: component A 100 wt. parts B, 25 to 35 wt. parts, limestone micronized 25 wt. parts, diatomaceous earth size max.

0.2 mm 12 wt. parts and ocher ground 3 wt. parts. Within 30 to 40 minutes, depending on the temperature, this sealing sealant will undergo a chemical reaction - polycondensation - from a liquid phase to a solid sealant with a high elongation and good chemical resistance to aggressive media.

This encapsulating sealant is characterized for a longer time by increasing its volume in the transition phase of the phase change, which results in a closed overpressure space, and the encapsulating sealant fills the entire enclosure perfectly and penetrates all tiny gaps, joints and pores.

In the transition phase it is further characterized in that it has excellent adhesion to all conventional materials and thus also to the materials defining the closed space of the joint. Over time, adhesion decreases negligibly. High adhesion is maintained even when the sealing sealant is applied to a slightly damp surface or at high relative humidity.

The high adhesion and internal pressure of the sealing sealant in the transition phase makes it possible to use pipes with untreated pipe ends.

The high elongation and adhesion values of the resulting elastic sealant allow for considerable dilatations from the temperature without compromising the tightness of the pressure joint.

The pipe connection method according to the invention is applicable in various fields and areas of the national economy, where it is necessary to connect glass-lanced winding pressure pipes.

Claims (1)

Method for joining pipes, in particular fiberglass winding pressure pipes, characterized in that the ends of the pressure pipes are spaced apart, a rigid sleeve, the inner diameter of which is larger than the outer diameter of the pipes, the gaps formed between the rigid sleeve and the outside of the pipe are blinded and a sealing sealant is applied to the inner surface of the pipe at the point of contact of the pipe and a sealing curing compound is introduced into the connecting space.