BACKGROUND OF THE INVENTION It is known that glass-fibre-reinforced plastics are expensive materials and at designing machinery and pipelines of them even small improvement of construction or technology can essentially reduce the ultimate cost of goods. Therefore, it is necessary to approach the improvement of glass fibre goods very carefully. The basic advantages of machinery of glass-fibre-reinforced plastics are high reliability and long service life in conditions of constant effect of chemical aggressive environment, frequently in combination with high loading. Therefore, diminution of machinery cost of glass-fibre-reinforced plastics at the expense of applying new materials or accelerated paces of treatment should not result into decrease of quality of goods, decrease of durability, as, in the end, a consumer will not only receive expected savings, but will also remain at a loss [GLASS REINFORCED PLASTICS, edited by Phillip Morgan, London, Iliffi and Sons Ltd., New York, Philosophical Library, 1957 ; Mallinson J. H. Chemical plant design with reinforced plastics.-MCGRAW-HILL BOOK COMPANY, New York, St. LOUIS FRANCISCO LONDON SYDNEY TORONTO MEXICO PANAMA ; Kalinichev V. A., Makarov M. I. Winded glass- reinforced plastics.-M. : Chemistry, 1986.-272 c.] It is known, that for supplying the necessary mechanical strength and corrosion resistance, a pipe of glass fibre plastics should be multi-layered. The pattern structure of a pipe includes internal chemically resistant layer, the second layer, which together

with the first constructional layer provides impermeability and chemical resistance of a pipe. Further, it is possible to have an external protective layer [Mallinson J. H.

Chemical plant design with reinforced plastics.-MCGRAW-HILL BOOK COMPANY, New York, St. LOUIS FRANCISCO LONDON SYDNEY TORONTO MEXICO PANAMA]. The thickness of the constructional layer depends on the diameter of a pipe and actual loads. Dominating materials, which essentially influence the hardness of a pipe, are glass fibre of twist yarns, roving fabrics, glass fabrics.

Between two layers of tissue a layer of roving fabrics should be packed. On the last layer of tissue or glass roving a layer of glass fabric is also packed. The constructional layer can contain glass threads packed by the method of continuous spooling. Such tubes are chemically more resistant and have higher hardness. The maximal hardness of the constructional layer, with other things being equal, can be provided with longitudinally-transversally spooling (Its) of reinforced layers.

Such pipes are produced by contact moulding on mandrels of final length with the use of reinforcing material from twist yarns. The process of moulding includes operations, concerned with manual labour, it does not yield to automation, that has an effect on the output of moulding method, and as a consequence, has negative effect on the cost of final product.

It is also known that there are glass-fibre-reinforced pipes, which consist of the impregnated thermosetting binder layer of glass fabric, cross spooling layers of glass roving belts and, at least, of one layer longitudinally disposed glass roving fabrics (braids), uniformly distributed on the surface of a tube [the specification to the copyright certificate USSR No. 979776, 1. cl. F 16 L 9/12, from-1. 08. 80], at that time the longitudinally disposed glass roving fabrics (braids) interlace with belts of the

cross wound layer, but cross wound layer consists of two belts disposed under and above the layer of longitudinally disposed in identical direction of glass roving fabrics (braids) and the upper belt is offset relatively the lower one on half a step.

Such engineering solution ensures additional mechanical fixing of longitudinal and transversal glass roving fabrics (braids) among themselves at the expense of their interlacing that increases hardness of a pipe.

The described above construction of a tube is also carried out by the method of contact moulding, supplying a pipe fabrication of final length on a mandrel. The applying of such a method, as well as in the previous case, is conditioned by the construction of a pipe and essentially has an effect on the cost of final goods. In this case, actually, the entire pipe wall represents the constructional layer dispossessed of internal and exterior defensive layers, which has lower hardness in comparison with the constructional layer having longitudinal-transversal pattern of reinforcing material.

The nearest to the declared decision for setting, engineering substance and achievable result at use is the constructional layer of a pipe of composite, which is made of reinforcing glass fibre material as alternate mono-layers with the transversal and longitudinal reinforcing glass fibre material structure, which is impregnated, for example, by thermosetting binder, at the same time in longitudinal direction reinforcing glass fibre material is packed by zigzag, the tops of each zigzag loops are fixed by the pressing glass fibre, forming the oblique-layered longitudinal-transversal structure (olts), in which longitudinal and transversal packing reinforcing glass fibre material forms laminated structure, in which each following mono-layer is displaced relatively to the previous one in the longitudinal direction and along the circumference [Andreev G. Y., Sherjukov G. E., Shevchenko V. Y., Dardik Y. I.-

Fabrication of glass fibre pipes.-Kharkov : Publishing House KSU, I964-96 p.].

The pipes with the described above constructional layer are produced by the method of continuous filament spooling, for example, of reinforced plastic, and contain an internal reinforced layer, the constructional layer of reinforcing material, impregnated by thermosetting binder, and also an external layer with transversal packing of reinforcing material, impregnated by the binder. The pipes of the indicated construction were produced with the diameter from 75 up to 300 mm, with wall thickness from 0, 5 up to 15 mm, with the contents of glass fibre on bulk 55-60%, on weight 72-75%. The fibre in the form of glass roving in 10-20 compositions with the diameter of a filament 5-7 or 9-12 microns was used as initial material. It is necessary to mark, that at use the oblique-layered longitudinal-transversal spooling (olts) the thickness of the constructional layer is more, in comparison with the thickness of the constructional layer obtained by longitudinal-transversal spooling (lts).

However, as the practice has shown, the magnification of the thickness of the constructional layer does not effect directly proportionally the hardness of a pipe as a whole, as in thick-walled patterns, for example, the defects of different kind are accumulated. Besides, the magnification of the thickness of the constructional layer leads to unjustified expenditure of both reinforcing material and the binder that increases the cost of final product.

DISCLOSURE OF INVENTION Therefore, the aim of the offered technical decision is the working out of the constructional layer structure permitting the diminution of expenditure of reinforcing material and the binder at simultaneous supply of the necessary hardness.

The basis of the invention is the improvement of the pipe constructional layer of

composite, in which, in consequence of implementation of constructional layers of each pipe dimension-type in compliance with the proposed formulas ; it is ensured the possibility of choice of permissible variation of the constructional layer hardness from the greatest possible, which is ensured with longitudinal-transversal structure of the constructional layer, and, accordingly, with the thickness of the constructional layer, and at the expense of that, it is possible to reduce the expenditure of reinforcing and the binder material and the cost of final product.

The raised problem is solved so that the known constructional layer of a pipe of composite, which is made of reinforcing glass fibre material by the way of alternate mono-layers with the transversal and longitudinal pattern of reinforcing glass fibre material, impregnated, for example, by thermosetting binder, at the same time in longitudinal direction reinforcing glass fibre material is packed by zigzag, the tops of each zigzag loops are fixed by transversal glass fibre threads, forming the oblique- layered longitudinal-transversal structure, at which longitudinally and transversally packed reinforcing glass fibre material forms laminated structure, in which each following mono-layer is displaced relatively to the previous one in the longitudinal direction and along the circumference, according to the invention, the connection of the structure parameters of the reinforcing glass fibre material of the constructional layer of each pipe dimension-type and expected (preset) index (Y, %) of deflection of the constructional layer hardness, containing the oblique-layered longitudinal- transversal structure of reinforcing glass fibre material, relatively to the hardness of the constructional layer, containing the longitudinal-transversal structure of reinforcing glass fibre material, is determined by the formulas

2D Y = G * C2 L * (Z1)' C-structural coefficient ; G-numerical coefficient, equal to 82, 15 for delivery pipes ; D-inside diameter of the constructional layer, cm ; L-base of a longitudinal glass fibre-packing, cm ; z-amount of zigzag loops on the length of the inside diameter circle of the constructional layer.

According to preferred embodiment of the invention, the structural coefficient has values within the limits 0 < C < 0, 6.

Implementation of constructional layers in compliance with the offered formulas provides the receiving of composite with smaller amount of defects, concerned with the failure of the constructional layer structure (malfunctions in packing of zigzag loops), and also defects, which are accumulated in a thick binder layer. The diminution of the influence of these factors also allows to ensure the necessary hardness of constructional layers at smaller thickness, and, therefore, at smaller expenditure of the reinforcing glass fibre material and the binder.

The magnitude of structural coefficient predetermines a choice of optimal proportion of parameters of structure for each dimension-type.

As it is seen from the specification of the engineering solution, which is declared, it differs from the prototype and, therefore, it is new.

The solution also has an inventive level. It is known that the constructional layer serves for supplying the demanded hardness and rigidity of a pipe [GLASS REINFORCED PLASTICS, edited by Phillip Morgan, London, Iliffi and Sons Ltd., New York, Philosophical Library, 1957]. The layer thickness can be varied depending

on the diameter of a pipe and external ladings. Twist yarn fabrics, roving fabrics, glass fabrics are reinforcing glass fibre materials. Such pipes have properties necessary for their use in aggressive environments and at increased pressure. However, the cost of these pipes considerably exceeds the cost of pipes manufactured with the constructional layer in compliance with the offered engineering solution. It is connected not only with the impossibility to utilize (for fabrication of pipes) more productive method of continuous filament wound production of infinite hollow bodies [specification to the patent of Ukraine No. 24485 A, IPC B 29 D 23/00, of 06. 05. 97], but also heightened expenditure of reinforcing material and the binder, in particular at forming the constructional layer.

The offered invention principally solves this problem. It allows, depending on the conditions of exploitation of a pipe, to select the optimal geometrical sizes of the constructional pipe layer of reinforcing plastic at packing reinforcing glass fibre material by the method of oblique-layered longitudinal-transversal spooling, ensuring minimally possible cost of final product. Besides, the offered solution enables to utilize rather strong constructional layer at the expense of use of more thin layers with smaller amounts of defects at implementation of conditions of necessary hardness of final product.

INDUSTRIAL APPLICABILITY The offered engineering solution can find broad applying in commercial production of pipes of composites, in particular of reinforced plastics.

BRIEF DESCRIPTION OF DRAWINGS The pattern of the constructional layer, which is treated during moulding of a pipe, is shown on the figure (evolvent).

MODE FOR CARRING OUT THE INVENTION The constructional layer of a pipe of reinforcing glass fibre plastics, impregnated thermosetting binder, by the way of alternating mono-layers with oblique-layered- transversal 1 and longitudinal 2 packing of a reinforcing material, thus longitudinal reinforcing material is packed with altitude of a zigzag (base) L. The tops of each zigzag loop are fixed by transversal glass thread 3. Longitudinally 2 and transversally 1 packed reinforcing material forms lamellar structure, in which each following mono- layer is displaced relatively to the previous one in the longitudinal direction and along the circumference on magnitudes t and kl2.

After a choice of value Y, using the formulas y h (olts) =h (lts) * r 00] and (3) P * D h (lts) = 0, 75 *----, where where<BR> L ou h (lts)-thickness of the constructional layer with longitudinal-transversal structure of reinforcing material, cm ; h (olts)-thickness of the constructional layer with oblique-layered longitudinal- transversal structure of reinforcing material, cm ; [c-]-allowable stress in a wall of a pipe, kg/cm2 ; P-exploitation stress in a pipe, kg/cm2, it is possible to calculate alternatives of structure of the constructional layer and to select an optimal one for realization.

The performances of possible constructional layers executed in compliance with the offered solution are shown in Tables 1 and 2.

As it is seen from Table 1, at fixed values of magnitude of base of a zigzag (L) and the amount of zigzags (z), packed on a circumference applicable to a definite inside diameter (D), the expected (preset) index (Y) of deflection of hardness of the constructional layer increases in accordance with magnification of an inside diameter of the constructional layer. For supplying the necessary hardness it is necessary to increase the thickness of the constructional layer with oblique-layered longitudinal- transversal structure (olts) of reinforcing material in comparison with the thickness of a layer with longitudinal-transversal structure (Its) at some values D more than 50 %.

As it is seen from Table 2, at fixed (preset) value of an index (Y), selecting the applicable values L and z, the thickness h (olts) for delivery pipes of miscellaneous dimension-types is determined.

Thus, from Table 2 it is seen, that, utilizing the proposed method of forming the constructional layer in compliance with the offered formulas, it is possible, at known requests to the hardness of final product, to reduce the expenditure of reinforcing material and the binder, and consequently the cost of final product, by diminution of the thickness of the constructional layer.

Table 1 NND, cm P. kg/em L, cm z Y, % h (olts), cm h (lts), cm 1 5 50 20 9 0,321 0,627 0, 625 2 10 35 1, 284 0, 886 0, 875 3 15 20 2, 888 0, 772 0, 750 4 20 15 5,135 0,789 0, 750 5 25 10 8,023 0,625 0, 625 6 30 10 11, 55 0, 838 0, 750 7 40 8 20, 54 0, 964 0, 800 8 50 6 32, 09 0, 991 0, 750 9 70 4 69, 90 1, 189 0, 700 Table 2 D, cm P, kg/cm2 L, cm Z Y, % holts, cm hlts, Cm 1 5 50 7 5 10 0, 6875 0, 625 2 10 35 10 7 0, 9625 0, 875 3 15 20 15 7 0, 8250 0, 750 4 20 15 15 9 0, 8250 0, 750 5 25 10 15 11 0,6875 0, 625 6 30 10 20 9 0,8250 0, 750 7 40 8 20 11 0,8800 0, 800 8 50 6 30 11 0,8250 0, 750 9 70 4 40 11 0, 7700 0, 700