WO2001014073A1

WO2001014073A1 - Flush device for inside flushing of pipes

Info

Publication number: WO2001014073A1
Application number: PCT/NO2000/000275
Authority: WO
Inventors: Inge JØSANG
Original assignee: Jøsang Tv Rørinspeksjon As
Priority date: 1999-08-24
Filing date: 2000-08-22
Publication date: 2001-03-01
Also published as: NO994067L; NO994067D0; AU7042700A; NO310280B1

Abstract

A device for the internal washing of pipes (10), comprising a carriage section (12), a driving section (20) for driving wheels (44) of the carriage (12), an intermediate transmission section (28, 28a, 32, 56, 66, 70, 64) and a washing section (14), comprising at least one high-pressure washing nozzle (18). The washing section (14) with its nozzle(s) (18) is arranged to rotate about the longitudinal axis (72) of the device, while the driving section (20) is making the carriage section (12) move in the direction of said longitudinal axis (72). To ensure that the spraying from the nozzle(s) (18) of the inner wall surface (10a) of the pipe (10) is complete and thus covers the entire inner wall surface (10a) in 360° over the whole length of pipe passed by the device, the washing section (14) is fixed against rotation on a central, coaxial, rotatable shaft portion (28a) incorporated in the transmission section (28, 28a, 32, 56, 66, 70, 64) for the driving wheels (44) of the carriage section (12) driven by a central, coaxial rotatable worm screw (32) which is fixed against rotation on said rotatable shaft portion (28a), whereby an increase in the rotational speed of the driving wheels (44), causing an increase in the propulsion speed of the device, automatically brings the nozzle(s) (18) to rotate faster about the longitudinal axis of the device.

Description

Flush device for inside flushing of pipes.

This invention relates to a device for the internal washing of pipes, comprising a carriage section, a drive section for the driving wheels of the carriage, an intermediate transmission section and a washing section, which comprises at least one high-pressure washing nozzle, said washing section being arranged to rotate about the longitudinal axis of the device while the drive section makes the carriage section move forward.

Devices of this kind have the form of so-called pipe, tractors equipped with washing nozzles, with washing liquid supply means and propulsion means, the devices being well suited for internal cleaning of all kinds of pipes, for example oil pipes .

On such washing devices it has been known earlier to use rotating nozzles, spraying out washing liquid while the device is moving forward inside the pipe. In known washing devices of this kind, the pressure of the washing water supplied also serves to drive the traction mechanism of the pipe tractor, so that the washing power of the nozzles is reduced.

Known washing devices of this kind are also highly inaccurate, and when a washing operation over a certain length of pipe is finished, one cannot know for certain which internal areas of the pipe have been washed properly clean over said length. Often, essentially only a fairly wide helical strip-like portion inside the pipe has been washed thoroughly clean, whereas the intervening portions have been washed only partially clean. This is due to the fact that it is difficult to adjust suitably, one according to the other, the forward traction rate of the washing unit, for example a tractor, and the ejection rate of washing water from the nozzle(s) .

In accordance with the present invention, the aim has therefore been to ensure cleaning of the entire internal wall surface of the pipe, through which the tractor is moving, practically independently of the traction rate of the pipe tractor, which results in a reduction in the washing time per length unit of pipe to the absolutely necessary operation time, while at the same time the jets of the washing nozzles hit the internal pipe wall surface in mutually overlapping, circular "washing windings" to ensure cleaning of the entire internal pipe wall surface area, through which the washing device .of the pipe tractor is moving during the washing operation.

This and closely related objects are realized, according to the invention, by configuring a device according to the introductory part of Claim 1 so that it also exhibits the features specified in the characterizing part of Claim 1.

The pipe tractor comprised by the device according to the invention carries and moves forward a washing device, comprising at least one nozzle rotatable about the longitudinal axis of the device, the axis coinciding in use with the longitudinal axis of the pipe, and preferably comprises two sets of wheels, spaced apart axially, of which at least one set is driven, the circumferential surfaces of said wheels bearing rotatably on the internal pipe wall surface in a friction-creating manner. At least the wheels of one set of wheels are rotatably drivable.

Through a suitable transmission mechanism, the wheels of the pipe tractor's driven set of wheels are driven by a central rotatable element, for example a worm screw, which is driven in its turn by a motor, for example an air motor, through a transmission device consisting of gears and countershaft.

By the nozzle(s) being secured to said countershaft, which is tubular and carries washing water to the nozzle(s), and following the rotational movements thereof, which correspond with said worm screw driving the wheels of said driven set of wheels, a controlled washing effect is achieved, wherein cleaning of the entire internal pipe wall surface passed by the device during its concurrent longitudinal and rotational motion is ensured, because the washing jets form the nozzle(s) overlap all the time - independently of the traction rate of the device - in the direction of traction and in the circumferential direction. The driving motor in the form of said air motor, possibly an electric motor, is not critical for the device to function satisfactorily. Instead a hydraulic motor can be used, which is driven in a known manner by the water pressure, for example that of washing water supplied. Because of the efficiency of the washing device, this can be realized without major drawbacks.

A non-limiting example of a preferred embodiment will be explained in the following, with reference to the accompanying drawings, in which:

Fig. 1 is a side view, partially in axial section, of a device comprising a pipe tractor with a washing device and driving device arranged thereto, shown in the position of use inside a pipe, only one of the wheel mounting devices for respective propulsion wheels being visible in the sectional view;

Fig. 2 corresponds to Fig. 1, but does not show the driving device, but on the other hand the positions of three transversal planes (IV-IV, V-V, VI-VI), which form the basis of figures following (Figs. 4, 5 and 6);

Fig. 3 shows a perspective view of the carriage section (pipe tractor) of the device, in which one of the three wheel mounting devices, each serving to support and arrange a propulsion wheel, has been omitted for reasons of exposition;

Fig. 4 is a cross-sectional view along the line IV-IV in Fig. 2, seen in the direction of the arrows; Fig. 5 is a cross-sectional view along the line V-V in Fig. 2, seen in the direction of the arrows;

Fig. 6 is a cross-sectional view along the line VI-VI in Fig. 2, seen in the direction of the arrows.

Reference is made first to Figs. 1 and 2, in which a device for the internal washing of pipes 10 comprises a carriage section 12 in the form of a pipe tractor, which carries a washing section 14 of the device, in the form of a central housing 16 receiving washing liquid/water, and having a longitudinal channel opening into radial (transversal) channels with an outer, internally threaded portion, into which washing nozzles 18, which have a jet effect, can be screwed. The figures in the drawings show two nozzles 18 pointing in diametrically opposite directions, each pointing radially towards the inner wall surface 10a, which is to be washed clean, and the nozzle opening being at a certain relatively small distance from the inner wall surface 10a.

The driving device 20 of the device comprises a central housing 22 forming a socket for a swivel device 24 represented schematically, which receives a stationary pipeline or an incoming hose 26 for the supply of washing liquid to the nozzles 18 of the washing device 14, through a rotating tubular shaft/hose 28, whose (left-hand) end is screwed to the housing 16 and continues on the other side thereof as an extension shaft 28a, which can be rotated relative to a stationary sleeve 30 mounted externally, and a worm screw section 32 fixedly anchored to the shaft 28a.

The wheel sets of the pipe tractor 12 comprise a rear non- driven wheel set 34, comprising four radial arms 36 equally spaced in the transversal direction and carrying freely rotatable wheels 38 directed radially, see also Fig. 6.

The wheel sets of the pipe tractor 12 also comprise a front set 40 of driven wheels, comprising three radial arms 42 equally spaced in the transversal direction and in an angular distance of 120° relative to one another in a transversal plane perpendicular to the longitudinal axis 72 of the pipe tractor, Fig. 1.

At a certain distance within the outer free end of each arm 42, a propulsion wheel 44 is supported drivably rotational. The circumferential surface of each driven wheel 44 bears in a friction-creating manner on the inner wall surface 10a of the pipe 10 to move the pipe tractor 12 in the longitudinal direction of the pipe 10, when the wheels 44 of the driving wheel set 40 are rotated through driving power supplied.

In Fig. 5 each of these wheel-supporting arms 42 is shown in a double embodiment, i.e. consisting of two straight, plane, parallel, elongate plate-shaped elements which form a kind of wheel fork.

By a transversal trunnion 31 a pivotal point is established on the stationary sleeve 30 for a pivotal arm 46, which is formed, in its radially outer end portion, with an elongate hole 48, whose longitudinal direction coincides with the longitudinal direction of the pivotal arm 46, and in which hole 48 a guide pin 48' is displaceably engaged. This guide pin 48' is positioned at the outer end of the wheel- supporting arm 42, outside the pivot 57 of the wheel 44 on the arm 42. By this arrangement of elongate holes 48, and respectively engaging guide pins 48', it is provided for the wheels 44 to bear independently, elastically yielding on the inner pipe wall surface 10a of the pipe 10 with the possibility of springing back, so that the respective wheel 44 can yield in a direction radially inwards, to be "forced" resiliently back out then into the position of use after an obstruction has been passed. The above-mentioned pin 48' also limits the deflection of the respective wheel 44 in the radial direction prior to being pushed into a pipe. The arrangement with the elongate holes and the respectively engaging guide pins 48' is however the most important in connection with driving in pipe bends.

The driven set of wheels 40 has a transmission mechanism arranged thereto for the rotational energy supplied through the shaft 28,28a from the driving device 20, in which 50 identifies a driving motor, for example an air motor, whereas 52 identifies a rotation of the axle 28 driven by gear transmission. The reference numeral 54 identifies a stationary incoming hose for the supply of air for driving the air motor 50, whereas the stationary hose 26 carries washing liquid/water under high pressure, for example about 2,000 bar, to the nozzles 18 of the washing device 14.

The washing device 14 sits fixedly mounted on the hose/shaft 28,28a, and thus participates in the rotational movement of the latter together with the worm screw 32.

The worm screw 32 drives toothed worm gears 56 whose pivot 58 is supported on a frame element 60, which is arranged rotational on the end of the axel 28a and is fixedly anchored to a ring element 62, which is stationary relative to the shaft 28a and is secured to the left-hand end of the sleeve 30, so that the frame element 60 etc. remains stationary and does not follow the rotational motion of the shaft 28a. Of course, the same applies to the support arms 42 fixed to the frame element 60, the arms 46 etc. and the propulsion wheels 44. On the pivot 57 of a respective propulsion wheel 44, extending through the respective support arm 42 of a propulsion wheel 44, a chain wheel 64 is tightly wedged.

On the pivot 58 of the worm gear 56, there is also tightly wedged a second chain wheel 66, whose pivot 58 is supported in the end portion of the respective support arm 42 of each propulsion wheel 44.

Around the chain wheels 64 and 66 are placed an endless chain 70 to transfer the rotation of the worm screw 32 to each propulsion wheel 44.

The shaft 28,28a, which rotates about the central longitudinal axis 72 of the device, and rotates, through the worm screw 32 and the transmission mechanism, each propulsion wheel 44 about the wheel axis, is fixed to the washing device 14, which follows, together with its nozzles 18, the rotational movements thereof. This is the arrangement that provides a controlled washing effect, in that for a rotation of the shaft 28, 28a it is known how far the carriage section 12 has moved. Consequently, the spraying of the nozzles and the forward movement per rotation can be adjusted.

If the rotational speed of the shaft 28,28a is increased to make the propulsion wheels 44 rotate faster, with the intention of increasing the general traction rate of the device, the same increased rotational speed is applied to the washing device/nozzles, and thereby maintains the desired degree of jet-overlapping of the nozzles 18. Thereby, cleaning of the entire 360° internal pipe wall surface area, successively run through by the nozzles 18 as the device pulls forward in the longitudinal direction of the pipe 10, is ensured.

The configuration of the central rotatably supported shaft/hose, its division into individual lengths, and the joining thereof, are only suggested in Figs. 1 and 2. The reference numeral 74 thus identifies couplings visualized schematically, which can be of any kind suitable for the purpose, and do not constitute an object of the present invention.

In order for the propulsion wheels 44 to have the desired friction against the pipe wall 10a, springs 76 are provided between the frame element 60 and the support arms 42, with the pivots 58 as points of support. At its front end the spring 76 is placed in a bore in the front plate 78 of the frame element 60, and at its rear end the spring 76 has been placed under an angled element 42', which forms part of the support frame 42.

Claims

C l a i m s

1. A device for the internal washing of pipes (10), comprising a carriage section (12), a drive section (20) for the driving wheels (44) of the carriage (12), an intermediate transmission section (28, 28a, 32 ,56, 66, 70,64) and a washing section (14) comprising at least one high-pressure washing nozzle (18), said washing section (14) being arranged to rotate about the longitudinal axis (72) of the device, while the driving section (20) makes the carriage section (12) move forward, c h ar a c t e r i z e d i n that a rotatable element (32) incorporated in the transmission section (28,28a, 32,56,66,70,64) shares the axis (72) of rotation with, and is fixed against rotation to, a coaxial element (28a) carrying the washing section (14), so that the rotation speed of the washing section (14) about the longitudinal axis (72) of the washing device automatically increases if increased driving power is applied to the wheels (44) of the carriage section in order to increase the speed of motion of the carriage section (12) in the longitudinal direction (72) o of the washing device.

2. A device according to claim 1, c har ac ter i z ed i n that said element (32) incorporated in the transmission section (28,28a, 32, 56, 66, 70, 64) is formed by a worm screw section engaged by a worm gear (56) rotating together with a 5 first pin (58), on which a chain wheel (66) is fixed, an endless power transmission chain (70) being placed over this chain wheel (66), and a chain wheel (64) arranged at a distance therefrom and rotating about a second pin (57) supported at one end of an arm (42), possibly between o individual elements of a double arm or fork-shaped arm (42), and forming the rotary shaft for one of the rotatable, drivable wheels (44) of the carriage section 12, the second end of said wheel-supporting arm (42) being supported by the first pin (58) on a frame (60), which is rotatably supported relative to the worm screw section (32).

3. A device according to claim 2, c h ar ac ter i z ed i n that said wheel-supporting arm (42), which is pivotal on a first pin (58) at its radial innermost end, is provided with a third pin (48') parallel with the first and a second pin (58, 57), in the form of a guide and stop pin, in displaceable and motion-restricting engagement with an elongate hole (48) in a second arm (46), pivotal about a transversal axis (31) at its radially inner end, and connected there to a sleeve (30), which is stationary relative to the rotating worm screw section.

4. A device according to any one of the preceding claims, c har ac t e r i z ed i n that the device has two sets (34, 40) of wheels spaced apart axially, one set on either side of the washing section (14), a first wheel set (40) with individually rotatable driving wheels (44), and a second wheel set (34) in which the wheels (38) are non-driven, freely rotatable, each wheel (38) being arranged with its pivot displaceable in an elongate hole (49) in the radially outer end of radial arms (36).