SU673800A1 - Double-wall pipe - Google Patents

Description

(54) DOUBLE WALL PIPE

one

The invention relates to the production of spiral-seam multilayer pipes and can be used when pumping liquids under Pressure, hydro-pulps, etc., when a pipe, in addition to internal pressure, is subjected to internal abrasive wear and mechanical loads.

Pipes with double walls, separated by ribs located along a helical line of constant pitch along the entire length of pipe 1 are known.

In order to increase service life, cost of production and reduce hydraulic resistance along the length of the pipe, in the described pipe, the ribs are made with an external weld of the inner wall of the pipe, and in the lower part of the internal pipe there are uniformly spaced holes along its length, the total length of which should be equal

SF6 - gt-С 8 00. “. -1-Yu.5 C.) - FO S, p (ct-l)

where ZF6 is the total area of the side holes;

VK - slurry speed at the end

pipeline;

Vo is the slurry speed at the beginning of the pipeline;

Sqi is the resistance coefficient of a unit for the length of the pipeline; Fg is the cross-sectional area of the internal pipeline.

FIG. 1 shows a pipe, a general view; in fig. 2 shows section A-A in FIG. one.

The pipe consists of an outer 1 and an inner 2 wall, which are interconnected by a weld 3, and the adhesion force is adjusted during the welding of the outer pipe 1 by tensioning the rotating roller mandrel of the spiral-seam-welded mill.

The outer wall of the pipe is made of mild steel, and the inside is made of wear-resistant stainless steel of class X13-X17 (for example, 1X13, 4X13, 45X17US).

Claims (2)

The seam 3 of the inner wall is made with electrodes (for example, brand NZL / 17 type EF-X13 according to GOST 10052-62) or welding wire (CB-12X14, CB-12X13 according to GOST 10052-62), providing them with high physicomechanical properties After the war (4 67kg / mm2, yo 55kg / mm2, and 520 / o; $ 18%; and to 9.6). The height of the seam 3 is 1-5 t of the inner wall, where t is the sheet thickness. The lower part of the inner wall of the pipe is made perforated, and perforation is performed preliminarily on the stripe by means of a casting during the movement of the strip in the mill flow. The outer wall, resting on the weld 3, forms an endless screw cavity 4 with the inner wall of the pipe. The internal cavity serves to pump the slurry, and through the screw cavity 4 water is supplied under greater pressure than the slurry stream. Water through the perforation 5 enters the internal cavity of the pipe and reduces the consistency of the slurry in the lower part of the internal cavity. This increases the service life of the pipe, since the solid phase of the slurry is usually mixed to the bottom of the pipeline. In addition, punched holes are used to reduce post-weld stresses and deformations in the welding area. In the case of a uniform inflow and the presence of transit flow, the drag coefficient L is expressed by the dependence), ()), (g where A is the average drag coefficient per unit length of the pipeline; a is ..Vje.,. Vo "and YO is respectively the slurry speed at the end and the beginning of the pipeline; the total area of the lateral holes; Ro is the cross-sectional area of the internal pipeline. At certain values and a, the resistance coefficient L may be zero or negative. In these cases, the energy loss can be considered small. reading that, L 0 and, solving the above equation with respect to TF6, we obtain the total area of the side holes, at which the energy costs of overcoming the resistance of friction of the slurry on the walls of the pipeline will be minimal: Vr .; (OS-0. The use of the proposed technical solution increases the service life and wear resistance of pipes by making the inner wall of the pipe made of wear-resistant stainless steel and reducing the hydraulic resistance coefficient; provides the possibility of making pipe walls from different materials; reduces energy consumption for transporting slurry by reducing the hydraulic resistance coefficient. Claim 1. Double-walled pipe, separated by ribs located along the helix of a constant schag along the entire length of the pipe, characterized in that, in order to increase the service life of production efficiency and reduce the hydraulic resistance along the length of the pipe, the ribs are made by an external weld seam inner pipe wall. 2. A pipe according to claim 1, characterized in that in the lower part of the inner pipe there are holes evenly spaced along its length, the total area of which must be equal to EF6 (Sct.-no, 5M.) - Fo S4. ((T- ") Where EF6-sum.marna area of the side holes;" UK1.; ® -T UK - speed of the hydraulic mixture at the end of the pipeline; Vo - slurry speed at the beginning of the pipeline; Sep - coefficient of resistance of the unit of length of the pipeline; FO transverse area section of the internal pipeline. Sources of information taken into account during the examination 1. USSR Patent No. 313378, 1SA. F 16 L 9/18, 1967. / - / /