Device and method for scaling reduction in a dead water zone of a fluid conduit

Abstract

A scale-dampening or scale-inhibiting device is at a radial restriction in a pipeline. A helical flow guide is arranged in a pipeline portion upstream of the restriction. The flow guide projects radially inwards from a pipe wall and has a longitudinal direction slanted relative to the center axis of the pipeline. A method is for dampening or inhibiting scaling in a dead zone of a fluid flow downstream of a restriction in a pipeline.

Claims

1. A scale-dampening or scale-inhibiting device at a radial restriction in a pipeline wherein at least one continuous helical flow guide is arranged in a pipeline portion upstream of the radial restriction, the at least one continuous helical flow guide projecting radially inwards from a pipe wall and having a longitudinal direction slanted relative to a center axis of the pipeline, and wherein the at least one continuous helical flow guide forms a wall that provides two separate flow paths in the pipeline portion.

2. The scale-dampening or scale-inhibiting device according to claim 1, wherein a pitch of the at least one continuous helical flow guide decreases in the direction of the radial restriction.

3. A method of dampening or inhibiting scaling in a dead zone of a fluid flow downstream of a radial restriction in a pipeline, the fluid flow exhibiting an axial flow velocity wherein the method comprises: via at least one continuous helical flow guide projecting radially inwards from a pipe wall, providing a peripheral flow velocity at least on a lee side of the radial restriction.

4. The scale-dampening or scale-inhibiting device according to claim 1, wherein the at least one continuous helical flow guide is fixed along a length thereof to the pipe wall.

5. The scale-dampening or scale-inhibiting device according to claim 1, wherein the at least one continuous helical flow guide is configured to provide a first axial flow-velocity component together with a second peripheral flow-velocity component for fluid flowing in the pipeline.

6. The scale-dampening or scale-inhibiting device according to claim 1, wherein the at least one continuous helical flow guide is formed of a series of uninterrupted winding section, and includes an inlet end for directing fluid along the two separate flow paths to an outlet end which is spaced by the pipeline portion from and delivers the fluid at a peripheral flow-velocity on a lee side of the radial restriction via a free exit path therefrom.

7. A scale-dampening or scale-inhibiting device at a radial restriction in a pipeline wherein at least one continuous helical flow guide is arranged in a pipeline portion upstream of the radial restriction, the at least one continuous helical flow guide projecting radially inwards from a pipe wall and having a longitudinal direction slanted relative to a center axis of the pipeline, and wherein a smallest diameter of the at least one continuous helical flow guide is, maximally, equal to a diameter of the radial restriction.

8. The scale dampening or scale-inhibiting device according to claim 7, such that the at least one continuous helical flow guide and multiple radial elevations are fixed to and project radially inwards from the pipe wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In what follows, an example of a preferred embodiment is described, which is visualized in the accompanying drawings, in which:

(2) FIG. 1 shows a graphical representation of the simulated, resulting flow rate of a fluid flow at a restriction in a pipeline, the lower part a) showing the resulting flow rate without any scale-dampening or scale-inhibiting measures, and the upper part b) showing the effect of providing scale-dampening or scale-inhibiting means according to the invention upstream of the restriction;

(3) FIG. 2 shows, in a perspective and partially cutaway view, a portion of a pipeline provided with a first embodiment of the invention, a diametrical, helical wall extending in the axial direction in a portion of the pipeline; and

(4) FIG. 3 shows, in a perspective and partially cutaway view, a portion of a pipeline provided with a second embodiment of the invention, several radial elevations, projecting inwards from a pipe wall, extending in the axial direction in a portion of the pipeline.

DETAILED DESCRIPTION OF THE DRAWINGS

(5) In the drawings, the reference numeral 1 indicates a pipeline including a restriction 12 in a flow path 13 for a fluid flow 3. On a lee side 121 of the restriction 12, that is to say downstream of the restriction 12, a dead zone 31 is brought about in the fluid flow, that is to say a zone in which a flow rate V.sub.T is approximately zero according to the prior art (see FIG. 1a).

(6) In a first embodiment of the invention (see FIG. 2), a scale-dampening or scale-inhibiting means is provided in the form of a helical flow guide 2 which forms a diametrical wall that winds in the axial direction in a pipeline portion 1a upstream of the restriction 12. The flow-guiding wall 2 and pipe wall 11 define two separate flow paths 13, 13, which, because of the helical shape of the flow guide 2, provide a flow velocity component V.sub.P in the peripheral direction of the pipeline 1. Downstream of the flow guide 2, the peripheral flow velocity V.sub.P gradually decreases, and the flow guide 2 is therefore arranged in the immediate vicinity of the restriction 12. In any location in the pipeline 1, the vector sum of the peripheral velocity V.sub.P and an axial flow velocity V.sub.A constitutes a resulting flow rate V.sub.T.

(7) In a second embodiment of the invention (see FIG. 3), several scale-dampening or scale-inhibiting means are provided in the form of helical flow guides 2, 2 that project inwards from the pipe wall 11 and are substantially evenly distributed in the periphery of a flow path 13. The flow guides 2, 2 exhibit a height, that is to say an internal diameter D.sub.MIN, which, maximally, is equal to the internal diameter D.sub.FR of the restriction. In FIG. 3, the flow guides 2, 2 project further into the flow path 13 than the restriction 12.

(8) When a fluid flow 3 is provided in the pipeline 1, the flow guide(s) 2, 2 bring(s) about a peripheral velocity component V.sub.P in the flow 3. This leads to a far higher resulting flow rate V.sub.T being provided on the lee side 121 of the restriction 12 than on the lee side 121 of a restriction 12 where the pipeline 1 is not provided with one or more flow guides 2, 2, see FIG. 1a in comparison with FIG. 1b.

(9) The peripheral flow velocity V.sub.P on the lee side 121 of the restriction 12 is affected by, among other things, the flow rate of the fluid 3 at the entrance to the pipeline portion 1a, which is provided with one or more flow guides 2, 2, the distance between the flow guide(s) 2, 2 and the lee side 121 of the restriction 12, the difference between the internal diameters of the restriction 12 and the flow guide(s) 2, 2, the pitch P of the flow guide(s) 2, 2, especially the pitch P at the downstream end of the flow guide(s) 2, 2, and the viscosity of the fluid 3.

(10) The flow rates indicated in the figures are examples of how the flow guide(s) 2, 2 give(s) a positive effect on the flow rate downstream of the restriction 12. The flow rate that is necessary to prevent scaling is obtained from trials and experience with well fluids of different chemical compositions, and the design of the flow guide(s) 2, 2, for example the pitch P, is selected on the basis of what radial flow velocity component R.sub.R is desirably to be achieved at a specific fluid flow.