CS244072B1 - Wound laminate sandwich pipe - Google Patents

Abstract

The pipe with a sandwich structure of the casing is made of outer layers of polyester glass laminate and a core made of honeycomb. The pipe is provided with segments of polyurethane foam with a bulk density of 40 to 100 kg.m"*. placed in places of increased stress on the casing, or in places of holes and joints. The individual segments are connected by plastic knurled pins inserted into dowels.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wound laminate sandwich pipe with interposed ribs, the sandwich structure of the sheath consisting of outer layers of polyester glass laminate and a honeycomb core.

Wound laminate pipes of larger diameters, most often from 1 to 3 m, subject to higher loads, such as buried pipes, chimneys, television antenna jackets, cylindrical parts of large vessel shells and ground shafts are wasteful when performing single wall sheathing, especially for the excessive thickness of the laminate required to achieve the desired static reliability. The preferred solution in these cases is a sheathed pipe with sandwich structure, wherein the outer layers are laminate, honeycomb core, organic or inorganic rigid foam, or natural materials such as wood and cork. With the same laminate consumption, the rigidity of the casing can be increased by a factor of 10, better thermal insulation properties, more advantageous dynamic properties and greater reliability at accidental puncture can be achieved. The advantages of honeycombs are the low density of the core, low cost and simple production, the disadvantage is the lower strength and stiffness of the sandwich and the interconnected honeycomb cavities. Rigid foam, wood or cork cores give the sandwich greater strength and stiffness, but at the same time greater weight, are more expensive, and in the case of coiled pipes, production against honeycombs is more difficult.

According to the invention, the above-mentioned drawbacks are overcome by a wound laminate sandwich pipe with inserted ribs, the sandwich structure of the shell being formed by outer layers of polyester fiberglass and the core by a honeycomb. It is based on the fact that it is equipped with polyurethane foam segments with a density of 40 to 100 kg.m3, located in places of increased stress of the casing, or in the locations of openings and joints, the individual segments being

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- 2 connected by plastic knurled pins, inserted into the dowels.

The effect of the invention is to combine a lightweight honeycomb core in a wound laminate sandwich pipe with a core made of polyurethane foam segments to form stronger and rigid ribs in the pipe sheath where greater static or dynamic stresses or to form a sandwich structure in the sheath, in which it is easier to cut holes or make joints

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated in greater detail in the following examples, in which: Fig. 1 shows a longitudinal section through a pipe; Fig. 2 shows a cross section; and Fig. 2 shows a detail of a joint.

The sandwich pipe of 220 cm, length 500 cm, forms a cylindrical casing 2 of a container of volume 19, which is placed horizontally on two 15 cm wide seat supports. At the seats of the seats, i.e., a total length of 20 cm, the stress on the casing 2 is considerably greater than on the remaining length of 470 cm. If it is used in the cylindrical part along the entire length of the uniform core and a constant laminate thickness is maintained, the sheath 2, while maintaining the necessary static reliability at the abutment point, remains oversized at 94% of the surface, which is uneconomical. A more economical material consumption solution results in the reinforcement of the outer laminate at the abutments. However, this complicates the winding and the sheath 2 has an uneven surface, so in practice a sandwich with a constant laminate thickness is preferred. According to the invention, an economical solution provides a flat thickness of 2, with a honeycomb core and at the seat supports with inserted ribs of segments 1 of polyurethane foam with a density of 50 kg.m " By means of plastic serrated pins 2 inserted in the dowels 5 in the faces of the segments 1 and, moreover, by gluing the segments 1 with a thixotropic polyester sealant to the inner laminate sheath 2. The sealant simultaneously ensures greater cohesion of the polyurethane with the laminate.

According to another exemplary embodiment, a sandwich pipe of 2 m in diameter and 6 m in length forms a cylindrical portion of a standing container of 42 m5.

A sandwich structure is chosen to achieve the required thermal insulation

244 072 of the housing 2, the greatest stress of which is in a relatively narrow area at the bottom contact. At these locations, instead of a honeycomb core, segments of 50 kg.m < 5 > density with the same effect as in Example 1 were inserted with the inlet and outlet pipes of 20 cm diameter. Polyurethane foam segments 1 of 100 kg / m < -1 > 30 cm and a thickness of 5 cm, corresponding to the thickness of the honeycomb. If the honeycomb consists of tubes as in example 1, the segment is connected by means of dowels 5 and plastic knurled pins 2 * In a sandwich with a polyurethane core, a circular hole can be easily cut, thereby inserting a 20 cm diameter pipe and connected simply by laminating to both the outer and inner tire 2.

Claims (1)

SUBJECT OF THE INVENTION Wound laminated sandwich pipe with inserted ribs, the sandwich structure of the sheath consisting of outer layers of polyester mesh laminate and a honeycomb core, characterized in that it is provided with segments (1) of polyurethane foam having a density of 40 to 100 kg.m5 placed at the points of increased stress of the sheath (2) or at the points of openings and joints, the individual segments (1) being connected by plastic knurled pins (3) inserted in the dowels (4).