WO2018162714A1

WO2018162714A1 - Grinding and cleaning tool for grinding and cleaning the inside of tubing and pipes

Info

Publication number: WO2018162714A1
Application number: PCT/EP2018/055911
Authority: WO
Inventors: Maria OVSIANNIKOW; Peter OVSIANNIKOW
Original assignee: Dakki Ab
Priority date: 2017-03-10
Filing date: 2018-03-09
Publication date: 2018-09-13
Also published as: SE1750276A1; EP3592478A1; EP3592478B1; SE541684C2

Abstract

The invention relates to a tool (100) for grinding and cleaning the inside of pipes by utilising the centrifugal force due to the rotation of the tool. The tool has several grinding elements (105), made of a hard material, e.g. cemented carbide, that are pushed towards the inside of the pipe by centrifugal force when the tool is being rotated. The tool is attached to a rotating flexible shaft (102), providing rotational movement to the tool. The tool consists of a distal part (101), onto which a flexible shaft (102) is attached; there is a proximal part (103) adapted to guide the flexible shaft through its' center; at least two elongated and flexible linking members (104) connecting the distal part (101) with the proximal part (103); grinding elements (105) attached to or being an integrated part of said flexible linking members; and a resilient spacer member (106) that keeps the distal and proximal parts apart.

Description

GRINDING AND CLEANING TOOL FOR GRINDING AND CLEANING THE INSIDE OF TUBING AND PIPES

TECHNICAL FIELD

The invention relates generally to the field of maintenance and/or treatment of pipes, such as tubing and pipes in family houses, apartment blocks and office buildings or in industrial or off-shore applications such as process industry, ships and the oil/gas industry. The invention in particular relates to a tool for grinding and cleaning the inside of pipes by utilising the centrifugal force due to the rotation of the tool.

BACKGROUND OF THE INVENTION Tools for the internal reaming and grinding of pipes in smaller dimensions, e.g. 30 - 150 mm, were developed about twenty-five years ago. The challenges arose from the need to change pipes in buildings which was both costly and time consuming. The idea to renovate the piping would enable considerable cost savings, shorter times of operation and positive environmental effects. There was no need to remove functional surface layers and large quantities of scrap or garbage could be avoided. This technology developed and was subsequently divided in two distinct techniques, relining and coating. Common to both techniques is the need for cleaning or reaming the pipes to level of cleanness that a sealing product could be applied to the pipe walls.

At present known tools are commonly adapted to a certain pipe dimension and must be replaced when pipe dimension changes. Furthermore, the known tools suffer from the effect that forceful strikes can occur which can cause cracks and/or even holes in pipes with weak walls, e.g. where the wall has corroded.

Pipes and tubing systems in various types of constructions such as industrial buildings, dwelling houses, single-family houses as well as apartment blocks, and tubing systems in ships and in various industrial applications will need to be maintained by treating the inner side of the tubing, e.g.

performing cleaning or repairing of the tubing. A thorough cleaning could be performed once in a while, e.g. every 5 years, in order to maintain the tubing in a good condition. In many cases there is a need for a tubing to be reconditioned after 30-40 years and sometimes even earlier when it is suspected that damage has occurred in the tubing system. The cause may for example be deposits or accumulation of various types of substances forming insoluble lumps on the tube walls, corrosion, or damp-related damages.

A tool according to prior art is disclosed in International patent publication WO 94/08728 (Eklund).

Problems with prior tools for performing grinding and cleaning of the inside of pipes are the following. Under certain modes of operation they may become unstable and cause damage to the pipe; they may need to be fine adjusted to fit the specific pipe where they are used which may be time consuming thus reducing the efficiency in the work task to perform such grinding or cleaning; they may need a considerable amount of manual labour when produced, which is inefficient leading to high production costs and difficulty in scaling up production efficiently. In US 2016/0121377 Al (Virtanen) there is disclosed a cleaning device for the internal cleaning of drainpipes, which cleaning device includes one or more chains having several links. On one or more sides of one or more links one or more hard metal blades are fastened. This device suffers from the problem mentioned above of instability and need for adjustment. SUMMARY OF THE INVENTION

In order to remedy the problems associated with the prior art devices, the present inventors have devised a new tool that will reduce the risks discussed above considerably. This new tool is defined in claim 1.

In particular a device is presented that is intended as a tool for grinding and cleaning the inside of pipes, comprising a distal part to which a flexible shaft, such as a wire, is attachable, for example with a screw thread and clamping coupling, and a proximal part adapted to guide the shaft through the center of the proximal part, at least two elongated and flexible linking members connecting the distal part with the proximal part, grinding elements attached to or being an integrated part of said flexible linking members. The tool is provided with a resilient spacer member keeping the distal and proximal parts apart.

The elongated and flexible linking members are preferably constrained to move in any considerable amount in the azimuthal direction and could comprise chains of links, suitably of metal, preferably of steel.

In a preferred embodiment the resilient spacer member is a spiral spring, but could for example also be rubber or any other elastic material meeting the desired requirements.

Said distal part and proximal part respectively, would preferably have shapes for facilitating easy translation through the pipe.

The characteristics of the tool stem from azimuthal stability and force balance between centrifugal and longitudinal forces. The tool is stable during many modes of operation and thus does not endanger the pipe structure; it is self-adjusting in a way that removes the requirement to fine adjust the tool manually; and it can be manufactured in a highly automated process with a minimal input of manual labour.

The grinding elements comprise hard material, suitably in the form of irregularly shaped bodies with protruding pieces of hard, abrasive material, although other shapes and materials are possible and within the inventive concept.

In particular the resilient spacer member, suitably in the form of a spiral spring, will counterbalance the centrifugal force and will also balance the movement of the grinding links against the pipe wall. The spring will enable a smooth start-up that prevents strikes against the pipe wall. This is very advantageous during start-up and during the grinding operation and will significantly reduce the risk for damage. Furthermore the spring enables a smooth control of the geometry of the grinding links during operation, i.e. the desired grinding diameter for the grinding operation. This grinding diameter can easily be controlled by adjusting the speed of rotation of the flexible shaft. Increasing the rotation will bring about a larger grinding diameter and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

The following description should be read with reference to the appended drawing figures. These schematic figures are only intended for illustration of a number of embodiments of the invention and are not in any way intended to limit the scope of the invention. Fig. 1 is a cross-sectional view of a tool;

Fig. 2 is a view from above of one embodiment of the tool;

Fig. 3 is a schematic illustration of the tool in a relaxed, non-rotating state;

Fig. 4 is a schematic illustration of the tool while rotating;

Fig. 5a is an illustration showing grinding elements on a chain; Fig. 5b illustrates another embodiment of a grinding element;

Fig. 6 illustrates distal and proximal parts of the tool; and

Fig. 7 illustrates a clamping member for a flexible shaft.

DETAILED DESCRIPTION

The tool disclosed herein is usable for internal cleaning, reaming, and grinding pipe systems made of cast iron, concrete or plastic materials. Primarily the tool is adapted for pipe systems consisting of small (typically about 30 mm to 150 mm in diameter) and composite dimensions having diversions and and/or connecting pipes. Examples of such system can be found in e.g. buildings, ships, industrial and off-shore operations. The purpose can i.a. be to clean the pipe from e.g. deposits or slag products or to prepare the pipe for maintenance such as relining or coating, which will prolong the technical lifetime of the pipe system and improve its function.

Figure 1 is a view of a tool 100 in cross-section.

The tool 100 comprises a distal part 101, in the form of a first essentially dome shaped member (front member), to which a flexible shaft 102 is attached. There is a proximal part, in the form of a second essentially dome shaped member 103, referred to as a sliding member (rear member), and adapted to guide the flexible shaft 102 through its center, i.e. the shaft 102 slides in the sliding member 103. The flexible shaft 102 is suitably anchored in the front cone 101, preferably by clamping. To this end, suitably there is provided a clamping sleeve 102'. Thus the shaft 102 is rigidly mounted to the flexible shaft 102 by clamping, i.e. it is inserted into the sleeve 102' and the sleeve is deformed mechanically to clamp the shaft inside. The sleeve 102' has an external thread on a longitudinally protruding portion 102" mating with a corresponding inner thread (not visible in the figure) in the front member 101.

Between the front and rear members 101, 103, respectively a resilient elongated member 106, suitably a spiral spring, is provided.

At least two elongated and flexible linking members 104, also referred to as grinding links, connecting the distal part 101 with the proximal part 103. These linking members have been left out from Fig. 1 for clarity, but can be seen in Fig. 2. Grinding elements 105 are attached to or are an integrated part of said flexible linking members. The grinding elements can preferably be crushed hard metal soldered onto the links. Alternative embodiments are possible, one being discussed below. A resilient spacer member 106 keeps the distal and proximal parts apart. The spacer member is suitably a spiral spring, although other types are possible, such as rubber or any other elastic material that meets the requirements.

Auxiliary parts for the tool are e.g. a guiding tip 107. This guiding tip 107 comprises an essentially spherical or conical element attached to a flexible shaft, which is provided at its respective distal and proximal ends with quick fittings, suitably threaded, for attaching the spherical element at the distal end, and for attaching the guiding tip to the front cone 101, respectively.

Another auxiliary item is a stabilizer brush, attachable to the front cone 101, and the function of which is to support the spring 106 and to stabilize the rotation of the tool when coarse irregularities on the inner wall of a tube are encountered. A supplemental brush can be located behind the rear member 103 and will be idle.

Still another auxiliary item is a milling piece. This milling piece is connected to the front cone 101 and is used to remove obstacles blocking the path inside a tube.

Figure 2 illustrates the tool generally designated with reference numeral 100.

Also, one specific, non-exclusive example of the grinding elements 105 is shown in Fig. 2. These grinding elements comprise pieces of hard material (suitably crushed hard metal) soldered onto the linking members.

The flexible linking members 104 can for example comprise chains of metal links or sections of flexible wire. Said elongated and flexible linking members 104 are constrained to move in any considerable amount in the azimuthal direction, causing the tool during rotation to become azimuthally stable against the potentially destabilising effect of friction forces on the grinding elements 105 against the inside of the pipe as well as other dynamic forces. The linking members 104 should be symmetrically distributed circumferentially, i.e. when two linking members are provided they should be arranged 180° apart, three members should be spaced 120° apart, and four members 90° apart. Figure 3 schematically illustrates the tool 100 in a relaxed state, i.e. when it is not rotating.

In a relaxed state as shown in Figure 3, i.e. when the tool is not rotating, the resilient spacer member 106 stretches the tool to its maximum length and it obtains its minimum cross section. This enables the tool to be easily translated longitudinally through a pipe by pushing or pulling it via the flexible shaft 102. Translation of the tool longitudinally through the pipe can be done either manually or with the help of a pusher/pulling motor attached to the other end of the flexible shaft.

Figure 4 schematically illustrates the tool when it is rotated. When the tool is being rotated, the linking members 104 are pushed radially outwards due to centrifugal forces, causing the grinding elements 105 to grind against the inside of the pipe; and the resilient space member 106 to be actuated, for example if it 106 is a spiral spring, it is further compressed. Thereby the proximal part 103 will move along the flexible shaft 102 in the longitudinal direction towards the distal part 101. Centrifugal forces acting on the linking members 104 and the actuation force acting on the actuated resilient space member 106 thus counter each other resulting in a dynamic force balance for each rotational speed.

The resilient spacer member 106, for example a spiral spring, is used to keep the distal and proximal parts apart. The resilient spacer member 106 is placed in between the distal and proximal parts, with the flexible shaft 102 coaxially passing through it. When the tool is at rest, i.e. not being rotated, the resilient spacer member 106 is actuated slightly so that it pushes the distal 101 and proximal 103 parts away from each other, with the distal end of 106 leaning against the a surface 10 of the distal part 101, and the proximal end of 106 leaning against a flat surface 103' of the distal part 103. For example, if a spiral spring is used for the resilient spacer member 106 it is slightly compressed when put into place between the distal 101 and proximal 103 parts, with the flexible shaft 102 passing through it 106, with its 106 distal end leaning against the flat surface of the distal part 101, and its 106 proximal end leaning against the flat surface 103' of the proximal part 103, and thus the spring force press said parts away from each other until the flexible linking members 104 are stretched, in which state the whole assembly is in static force equilibrium.

The other end of the flexible shaft 102 is connected to a motor. When the motor rotates the tool by means of the flexible shaft 102, the centrifugal force forces the grinding links towards the pipe wall. The spring design will stabilize this centrifugal force such that the force with which the grinding links approach the wall is controlled by the rotational speed and the spring constant.

Suitably, a selection of different springs, e.g three, is provided which enable adaption to the nedds and the state of the pipes so as to achieve a smooth abutment against the pipe wall.

Depending on the rpm (revolutions per minute) the geometric shape of the links will vary from an ellipse at low rpm to a spherical shape at full speed (1200 rpm). During increased rotational speed the spring will become compressed and when the rpm is lowered the links will again be extended and become fully extended at zero rotation.

Figure 5a illustrates one embodiment of usable grinding elements 105. They comprise pieces 106 of hard metal soldered onto the individual links 104' on the linking members 104. The pieces can also be made from e.g. cemented carbide or another hard metal, diamond, cubic boron nitride, or the equivalent that is suitable for grinding.

Figure 5b illustrates another embodiment of the grinding elements 105'. The top surfaces 501 of the grinding elements 105' have the purpose of providing a grinding action against the inside wall of the pipe when the tool is being rotated. The top surfaces 501 are provided with several protrusions 502 at sharp angles in a repetitive pattern in order to provide such grinding.

The grinding elements 105' have features on them 503 that are intended for assembly of the grinding elements 105 to the flexible linking members 104. The grinding elements 105' can either be attached to the flexible linking members 104 or be an integrated part of said flexible linking members. Said features 503 can be for example drilled, pressed or casted holes that are suitable for connecting each of the grinding elements 105 to the flexible linking members 104. Either the whole of the grinding elements 105' or the top fraction thereof containing the top surface 501 which is intended for grinding, are made of a hard material, e.g. cemented carbide or another hard metal, diamond, cubic boron nitride, or the equivalent that is suitable for grinding.

The top surface 501 of each of the grinding elements 105, 105' is raised in relation to the flexible linking members 104, in a way such that there is a margin distance between the outermost surface of the flexible devices 104 and the grinding surfaces 501. Especially, it would be an advantage if this margin is at least 1.2, more preferred 1.5, measured as the ratio of the distance from the center longitudinal axis of the tool to the grinding surface, when the tool is at rest, and the distance from the center longitudinal axis of the tool to the outermost surface of the flexible devices. When the tool is being rotated and the grinding elements 105, 105' are pushed against the inside wall of the pipe due to centrifugal forces, the margin between the outermost surface of the flexible devices 104 and the grinding surfaces 501 secures that the wear on the flexible devices 104 is minimal and most of the wear is on the top surfaces 501 of the grinding elements 105, 105'.

Fig. 6a shows the proximal member (rear part) 103 in cross-section. It is essentially dome shaped having a central through hole 601 for accommodating a shaft 102. The proximal part 103 also comprises a recess 602 for receiving the resilient spacer member to keep it in place within the rear part 103, and a spring locating member in the form of a cylindrical sleeve 603 inside said recess 602 around which the spacer member 102 is positioned.

Fig. 6b shows the distal member (front part) 101. It is also essentially dome shaped and has a recess 604 for accommodating the distal end of the resilient member. It also comprises a threaded through hole 605 for receiving a clamping means for the flexible shaft, to secure said clamping means in a threaded engagement.

The clamping means 701 is shown in Fig. 7a. It comprises a sleeve portion 702 into which the distal end of the flexible shaft is inserted. When the shaft end is in place a tool is used to deform the sleeve 702 so as to clamp the shaft end in the sleeve. This can be seen in Fig. 1 indicated as an indentation IND. The clamping means is also provided with a threaded portion 703 extending distally in the longitudinal direction.

There is also provided a guiding means 704 (Fig. 7b) for the resilient member 106 such as a spring. This guiding means 704 has a similar sleeve 705 to the sleeve in the proximal part adapted for being enclosed by a distal part of the resilient member. The guiding means 704 also has a threaded hole 706 in which the threaded protruding part 703 of the clamping sleeve is insertable so as to be secured together with the guiding means. This is indicated by an arrow INS in Fig 7.

This combination of clamping means and guiding means can be placed in the recess for

accommodating the resilient member, and the protruding threaded portion 703 of the clamping means 701 can be screwed into the hole 605 in the distal part 101. Due its length the protruding part 703 will extend out from the end of the dome shaped distal part 101 to provide a location for auxiliary equipment as discussed above. In Fig. 1 it can clearly be seen how a guiding tip 707 has been screwed onto the protruding part. Fig. 7c shows such a guiding tip 707 that can be attached in the manner shown in Fig. 1. In Fig. 7c the dome shaped front member 101 has been left out but would be positioned in the space indicated between the vertical broken lines.

Claims

CLAIMS:

1. A grinding and cleaning tool for grinding and cleaning the inside of pipes, comprising a distal part (101) to which a flexible shaft (102) is attachable and a proximal part (103) adapted to guide the flexible shaft through the center of the proximal part (103), at least two elongated and flexible linking members (104) connecting the distal part (101) with the proximal part (103), grinding elements (105) attached to or being an integrated part of said flexible linking members, characterized by

a resilient spacer member (106) placed between the distal (101) and proximal parts (103), whereby the flexible shaft (102) can pass coaxially through it, thereby keeping the distal and proximal parts apart.

2. Tool according to claim 1, wherein the elongated and flexible linking members (104) comprise chains of links or sections of flexible wire (104).

3. Tool according to any preceding claim, wherein the resilient spacer member (106) is a spiral spring.

4. Tool according to any preceding claim, wherein said grinding elements (105) have grinding surfaces (501) that are raised in relation to the flexible linking members (104), such that there is a margin distance between the outermost surface of the flexible devices (104) and the grinding surfaces (501).

5. Tool according to any preceding claim, wherein the distance between the center longitudinal axis of the tool and the grinding surface, when the tool is at rest, is equal to or more than 1.2 times, preferably 1.5 times the distance between the center longitudinal axis of the tool to the outermost surface of the flexible devices.

6. Tool according to any preceding claim, wherein the distal part (101) comprises a screw thread coupling for attaching a flexible shaft (102).

7. Tool according to any preceding claim, wherein the distal part (101) comprises a clamping sleeve (701) threadingly engaged with the distal part (101) through its center.

8. Tool according to any preceding claim, wherein the proximal part comprises a recess (602) for receiving the resilient spacer member (106), and a spacer locating member in the form of a cylindrical sleeve (603) inside said recess around which the spacer member is positioned.

9. Tool according to claim 7, wherein the clamping sleeve (701) has an elongated threaded portion (703) which is provided for said engagement with the distal part (101) and which protrudes out from the distal part in the longitudinal direction, such that auxiliary equipment (707) can be positioned thereon, and preferably said auxiliary equipment is selected from a reaming element, a guiding element, a brush, a milling piece.

10. Tool according to any preceding claim, wherein the grinding elements (105), made of a hard material, preferably cemented carbide.

11. Tool according to any preceding claim 1-10, wherein grinding elements (105) have top surfaces (501) provided with a plurality of protrusions (502) at sharp angles in a repetitive pattern.