Tractor for propelling device inside cylindrical body

Abstract

The present disclosure relates to a retractor (10) for advancing a device (104) inside a cylindrical body (60). The retractor (10) includes a fluid motor (14). The retractor (10) further comprises a fluid guide conduit (15) adapted to guide fluid to the fluid motor (14). The retractor (10) further comprises a set of drive portions (20) comprising at least one drive portion (22), where each drive portion (22) of the set of drive portions (20) comprises:-a drive shaft (26) connected to the fluid motor (14), whereby the drive shaft (26) is adapted to rotate about an axis of rotation (30) of the drive shaft (26); -a set of propulsion members (34) comprising at least one propulsion member (12), preferably two or more propulsion members, each propulsion member (12) of the set of propulsion members (34) being non-rotatably fixed to the drive shaft (26); -a fluid-actuated control assembly (38) adapted to control a maximum distance (54) from the drive shaft (26) to each propulsion member (12) of the set of propulsion members (34) in a direction perpendicular to the axis of rotation (30) of the drive shaft (26); and-a fluid pressure gate assembly (72) adapted to allow the fluid directed via the fluid directing conduit (15) to be supplied towards the fluid-actuated control assembly (38) only if the pressure of the fluid exiting the fluid pressure gate assembly (72) is within a predetermined pressure range.

Description

Technical Field

[0001] The present disclosure relates to a tractor for advancing a device inside a cylindrical body. Further, the present disclosure relates to a device including the tractor. Background Art

[0002] Modern technology employs a variety of different mechanisms to operate inside cylindrical bodies such as oil wells and gas wells, water injection pipes, and production pipes. One such mechanism is a pipe tractor. Pipe tractors employ different mechanisms to advance or move the tractor inside a cylindrical or elongated body.

[0003] In one example, pipe tractors can be used in oil wells and gas wells for inspection and maintenance of pipes or hoses. These tractors are designed and manufactured specifically for offshore use and for transporting instruments through wells. The tractors may not always be suitable for other applications such as water pipe repair. Additionally, tractors for oil wells and gas wells on the market are designed to operate in the horizontal sections of wellbores.

[0004] WO 2022 / 129328 A1 discloses a device for advancing and operating inside a cylindrical body such as a pipe, the device including a central shaft, at least one motor and a motor control unit, a certain number of wheels arranged to rotate around the shaft at an inclined angle, and a sensor module including sensors. However, there is still a need to improve tractors for advancing devices inside cylindrical bodies. Summary of the Invention

[0005] In view of the above, an object of the present disclosure is to provide a tractor for advancing a device inside a cylindrical body, which can be controlled in a suitable manner.

[0006] The above object is achieved by a first aspect of the present disclosure according to claim 1.

[0007] Thus, a first aspect of the present disclosure relates to a tractor for advancing a device inside a cylindrical body. The tractor includes a fluid motor. The tractor further includes a fluid guiding pipe adapted to guide fluid to the fluid motor. The tractor further includes a group of driving parts, the group of driving parts including at least one driving part, wherein each driving part in the group of driving parts includes:

[0008] - a driving shaft connected to the fluid motor, whereby the driving shaft is adapted to rotate around the rotation axis of the driving shaft;

[0009] - a group of propulsion members including at least one propulsion member, preferably two or more propulsion members, each propulsion member in the group of propulsion members being non-rotatably fixed to the driving shaft;

[0010] - A fluid-actuated control assembly adapted to control the maximum distance from the drive shaft to each of the propulsion members in a direction perpendicular to the axis of rotation of the drive shaft; and

[0011] - A fluid pressure gate assembly adapted to allow fluid guided via a fluid guiding conduit to be supplied towards the fluid-actuated control assembly only if the pressure of the fluid leaving the fluid pressure gate assembly is within a predetermined pressure range.

[0012] A tractor according to the above means proper control of the supply of fluid towards the fluid-actuated control assembly. In particular, the above feature that the fluid leaving the fluid pressure gate assembly is within a predetermined pressure range means that the propulsion members can be controlled by selecting an appropriately high pressure, for example to start, so that the control can be turned on by controlling the fluid pressure. In addition, the predetermined pressure range also means that the risk of obtaining too high a torque from the propulsion members can be appropriately low, since the fluid pressure gate assembly will not allow a pressure higher than the upper limit of the pressure range to pass through the fluid pressure gate assembly.

[0013] Optionally, the predetermined pressure range is between a lower pressure limit and an upper pressure limit. The lower pressure limit is greater than 0 bar of relative pressure, preferably greater than 100 bar of relative pressure. The fact that the lower pressure limit is greater than any of the above thresholds means that there may be a lower pressure range of the fluid, for example, in the fluid guiding conduit, resulting in the fluid not being supplied towards the fluid-actuated control assembly. This in turn means an appropriate possibility of controlling when the fluid-actuated control assembly should control the above maximum distance and when it should not.

[0014] Optionally, the upper pressure limit is equal to or less than 10 times the lower pressure limit, preferably equal to or less than 5 times the lower pressure limit, more preferably equal to or less than 2 times the lower pressure limit. The upper pressure limit according to any of the above examples means that the risk of obtaining too high a torque from the propulsion members is appropriately low. This is because a high pressure supplied towards the fluid-actuated control assembly may result in a relatively large value of the maximum distance from the drive shaft to each of the propulsion members in a direction perpendicular to the axis of rotation of the drive shaft, which in turn may mean a relatively large contact force between the propulsion members and the inner surface of the cylindrical body. The above risk of having too high a contact force can be reduced by the upper pressure limit according to any of the above examples.

[0015] Optionally, the fluid motor includes a fluid motor fluid inlet and a fluid motor fluid outlet. The fluid pressure gate assembly is in fluid communication with the fluid motor fluid outlet such that at least a portion of the fluid pressure gate assembly is adapted to receive fluid from the fluid motor fluid outlet. The above means effective control of the fluid-actuated control assembly because the fluid pressure gate assembly and the fluid-actuated control assembly can use the fluid from the fluid motor fluid outlet instead of wasting the fluid discharged from the fluid motor.

[0016] Optionally, the fluid pressure gate assembly includes a first pressure reducing valve adapted to: allow fluid to pass through the first pressure reducing valve when the fluid pressure acting on the first pressure reducing valve is equal to or exceeds the first pressure reducing valve pressure threshold, thereby preventing fluid from being supplied towards the fluid-actuated control assembly. Preferably, the first pressure reducing valve is adapted to: allow fluid to flow from the first pressure reducing valve towards the surroundings of the tractor when the fluid pressure acting on the first pressure reducing valve is equal to or exceeds the first pressure reducing valve pressure threshold. The above features mean that excessive fluid pressure can be prevented from passing through the fluid pressure gate assembly.

[0017] Optionally, the fluid pressure gate assembly includes a second pressure reducing valve adapted to: allow fluid to flow from the second pressure reducing valve towards the fluid-actuated control assembly when the fluid pressure acting on the second pressure reducing valve is equal to or exceeds the second pressure reducing valve pressure threshold. The above features mean that, in the case where the fluid pressure is high enough, fluid can be allowed to pass through the fluid pressure gate assembly in a direct manner.

[0018] Optionally, at least one drive part in the drive part group, preferably each drive part, includes a booster, which, when viewed in the flow direction from the fluid pressure gate assembly to the fluid-actuated control assembly, is located between the fluid pressure gate assembly and the fluid-actuated control assembly. The booster includes a booster inlet and a booster outlet, where the booster is such that: in use, the fluid leaving the booster outlet has a higher pressure than the fluid entering the booster inlet. Preferably, the booster is adapted to be powered by the fluid entering the booster inlet. The boosting pressure can be used to increase the pressure of the fluid supplied to the fluid-actuated control assembly, which can simplify the control of the fluid-actuated control assembly. In addition, the booster means that the fluid guided through the fluid guiding pipe does not need to have a high pressure to control the fluid-actuated control assembly in an appropriate manner. Instead, the fluid guided through the fluid guiding pipe only needs to have a pressure high enough to allow it to pass through the fluid pressure gate assembly, and the pressure of the fluid actually reaching the fluid-actuated control assembly can be higher than the pressure in the fluid guiding pipe. This in turn means that the predetermined pressure range can be selected such that appropriate control of the fluid motor can be obtained, but the fluid-actuated control assembly can be controlled when needed without increasing the pressure of the fluid guided in the fluid guiding pipe to an excessive degree.

[0019] Optionally, at least one drive part in the drive part group, preferably each drive part, includes a fluid-actuated control component discharge port which, when viewed in the flow direction from the fluid pressure gate component to the fluid-actuated control component, is located downstream of the fluid-actuated control component. Preferably, the fluid-actuated control component discharge port is adapted to discharge fluid into the surroundings of the tractor.

[0020] Optionally, the fluid guiding pipe comprises at least one of or consists of at least one of the following: a coiled tubing or a group of threaded drill strings. When the tractor is advanced by means of a propulsion member, the propulsion member contacts the inner surface of the cylindrical body. Thus, when the drive shaft rotates about its axis of rotation, a torque is generated around the tractor. This torque may cause the tractor to rotate relative to the cylindrical body during propulsion, and such rotation may be undesirable as it may, for example, weaken the propulsion of the tractor. The coiled tubing or the group of threaded drill strings can provide a reaction torque which can reduce the risk of the tractor rotating relative to the cylindrical body during use.

[0021] Optionally, for at least one drive part in the drive part group, preferably each drive part, each propulsion member in the propulsion member group comprises a rim around the drive shaft, and preferably each propulsion member in the propulsion member group comprises a wheel, and the wheel in turn comprises a rim.

[0022] Optionally, the fluid-actuated control component is adapted to control the eccentricity of the rim relative to the drive shaft, thereby controlling the maximum distance from the drive shaft to each propulsion member in the propulsion member group in a direction perpendicular to the axis of rotation of the drive shaft.

[0023] Optionally, the rim extends in a rim plane. The rim plane forms a rim angle with the axis of rotation of the drive shaft. The rim angle is less than 90°, preferably less than 88°, more preferably less than 85°.

[0024] Optionally, for at least one drive part in the drive part group, preferably each drive part, each propulsion member in the propulsion member group comprises a propulsion member contact part adapted to contact the inner surface of the cylindrical body, and the maximum distance from the drive shaft to the propulsion member is the distance from the drive shaft to the propulsion member contact part in a direction perpendicular to the axis of rotation of the drive shaft.

[0025] Optionally, for at least one drive part in the drive part group, preferably each drive part, each propulsion member in the propulsion member group is adapted to: when the maximum distance is equal to or greater than a maximum distance threshold, transfer a force from the inner surface of the cylindrical body to the drive shaft. The above means that the propulsion member can contact the inner surface of the cylindrical body by increasing the maximum distance.

[0026] Optionally, for at least one drive part, preferably each drive part, in the drive part group, each propulsion member in the propulsion member group is such that: when the drive shaft rotates about the axis of rotation and the propulsion member transfers force from the inner surface of the cylindrical body to the drive shaft, a propulsion force is applied to the tractor.

[0027] Optionally, for at least one drive part, preferably each drive part, in the drive part group, each propulsion member in the propulsion member group is such that: when the drive shaft rotates about the axis of rotation and the propulsion member transfers force from the inner surface of the cylindrical body to the drive shaft, the contact point between the propulsion member and the inner surface of the cylindrical body will change as the drive shaft rotates about the axis of rotation, such that the locus of subsequent contact points will form a spiral shape on the inner surface of the cylindrical body.

[0028] Optionally, the cylindrical body has a longitudinal extension direction in the longitudinal direction of the cylindrical body. The tractor is adapted to propel the device in a direction parallel and / or coaxial with the longitudinal direction of the cylindrical body. The above means a compact tractor.

[0029] Optionally, for at least one drive part, preferably each drive part, in the drive part group, in use, the axis of rotation of the drive shaft and the longitudinal direction of the cylindrical body form an angle with an absolute value less than 10°, preferably, the axis of rotation of the drive shaft is parallel and / or coaxial with the longitudinal direction of the cylindrical body.

[0030] A second aspect of the present disclosure relates to a tractor assembly, which includes a tractor according to the first aspect of the present disclosure, wherein the fluid guiding pipe is non-rotatably fixed to a part of the tractor. The tractor assembly further includes a fluid guiding pipe rotation lock, and the fluid guiding pipe rotation lock is adapted to prevent a part of the fluid guiding pipe from rotating relative to a part of the cylindrical body. As described above, when the drive shaft rotates about its axis of rotation and the propulsion member contacts the inner surface of the cylindrical body, torque can be generated. This torque can cause the tractor to rotate relative to the cylindrical body during propulsion. The fluid guiding pipe rotation lock can provide a reaction torque, which can reduce the risk of the tractor rotating relative to the cylindrical body during use.

[0031] A third aspect of the present disclosure relates to a device including a sensor and / or a tool and a tractor according to the first aspect of the present disclosure or a tractor assembly according to the second aspect of the present disclosure.

[0032] Optionally, the tool is adapted to receive fluid from a fluid-actuated control component discharge port of at least one drive part in the drive part group.

[0033] The fourth aspect of the present disclosure relates to a cylindrical body assembly, which includes: a cylindrical body; and a tractor according to the first aspect of the present disclosure, a tractor assembly according to the second aspect of the present disclosure, or a device according to the third aspect of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] With reference to the accompanying drawings, the following is a more detailed description of embodiments of the present disclosure cited as examples.

[0035] In the drawings:

[0036] Figure 1 is a schematic perspective view of a tractor for advancing a device inside a cylindrical body;

[0037] Figure 2 is Figure 1 an exploded view of the tractor shown in ;

[0038] Figures 3a - 3d shows an embodiment of a fluid-actuated control assembly;

[0039] Figure 4a shows another embodiment of a fluid-actuated control assembly;

[0040] Figure 4b shows a spiral shape;

[0041] Figure 5 schematically shows a hydraulic system of a tractor for advancing a device inside a cylindrical body;

[0042] Figures 6a - 6b shows an embodiment of the tractor;

[0043] Figure 7a -6c shows the tractor in different states;

[0044] Figures 8 - 10 shows an attachment of a tractor for advancing a device inside a cylindrical body; and

[0045] Figure 11 shows different configurations of the tractor. DETAILED DESCRIPTION

[0046] Figure 1 shows a tractor 10 for advancing a device inside a cylindrical body ( Figure 1 not shown in ). In the Figure 1 example shown, the tractor 10 includes a propulsion member group 12, which is in Figure 1is implemented as a wheel in the example. When the propulsion member 12 rotates about the axis of rotation A and the propulsion member 12 contacts the inner surface of the cylindrical body, a propulsion force parallel to the direction of the axis of rotation can be obtained. As explained in WO 2022 / 129328 A1, the propulsion force is obtained due to the fact that each propulsion member 12 will undergo a helical motion relative to the cylindrical body.

[0047] In the following description, the term "cylindrical body" is used to describe any kind of body having an elongated opening, such as a pipe, a conduit, a channel, a tube, a drilled well with or without casing. Examples are flexible risers, umbilical cables, oil or gas wells during or after drilling, oil or gas production pipelines, water pipes, wastewater pipes, process plant pipelines, geothermal wells, etc.

[0048] Figure 2 An embodiment of a tractor 10 for propelling equipment inside a cylindrical body ( Figure 2 not shown) is illustrated. The tractor 12 includes a fluid motor 14. The tractor also includes a fluid guiding pipe 15 adapted to guide fluid to the fluid motor 14. The tractor also includes a drive section group 20, which drive section group includes at least one drive section. In Figure 2 the example, the drive section group 20 includes one drive section 22. However, it is conceivable that a plurality of other embodiments of the tractor 10 may include a drive section group 20 that includes two or more drive sections.

[0049] Furthermore, as Figure 2 shown, each drive section 22 in the drive section group 20 (illustrated by a single drive section 22 in Figure 2 ) includes a drive shaft 26, which drive shaft is connected to the fluid motor 14, whereby the drive shaft 26 is adapted to rotate about the axis of rotation 30 of the drive shaft 26.

[0050] As a non-limiting example, the fluid motor 14 can be driven by a gas such as air. As another non-limiting example, the fluid motor 14 can be driven by a liquid such as oil or water. Thus, the fluid guiding pipe 15 can be adapted to guide gas and / or liquid to the fluid motor 14 according to any of the above examples.

[0051] Merely by way of example, the drive shaft 26 can be directly connected to the fluid motor 14. However, it is also conceivable that in an embodiment of the tractor 10, at least one drive shaft 26 can be indirectly connected to the fluid motor 14. Such an embodiment is shown in Figure 2 , which shows a non-limiting example in which the drive shaft 26 is connected to the fluid motor 14 via an interface module 19 and at least one flow module 21. In Figure 2In a non - limiting example, the flow module 21 includes a high - flow module 23 and a low - flow module 25. Regardless of the implementation of the connection between the fluid motor 14 and the drive shaft 26, the connection is preferably such that the rotation of a part of the fluid motor 14, such as the rotation of the stator or rotor (not shown) of the fluid motor 14, can be converted into the rotation of the shaft 26.

[0052] In addition, as Figure 2 shown, each drive part 22 in the drive part group 20 includes a propulsion member group 34, and the propulsion member group includes at least one propulsion member 12, preferably two or more propulsion members. Each propulsion member 12 in the propulsion member group 34 is non - rotatably fixed to the drive shaft 26. In Figure 2 an embodiment, the propulsion member group 34 includes four propulsion members 12, and each of which includes a rim, as will be described in detail below. The propulsion member group 34 including two or more propulsion members means that the possibility of keeping the drive shaft 26 radially in place relative to the cylindrical body 60 (see, for example, Figure 7b below) during the propulsion of the tractor 10 is increased.

[0053] In addition, each drive part 22 in the drive part group 20 includes a fluid - actuated control assembly 38, and the fluid - actuated control assembly is adapted to control the maximum distance 54 from the drive shaft 26 to each propulsion member 12 in the propulsion member group 34 in a direction perpendicular to the rotation axis 30 of the drive shaft 26 (see below Figure 3a ).

[0054] By way of example only, as Figure 2 shown, the modules 19, 23, 25 and the drive part 22 may include connecting means and may be configured to be releasably connected in series with each other. For this purpose, the connecting means may include bolted joints (not shown) adapted to connect adjacent components together. As another non - limiting example, the connecting means may include threaded members (not shown) such that adjacent components can be connected together by means of relative rotation between the components. In addition, the modules 19, 23, 25 and the drive part 22 may be such that fluid flow can be introduced from the fluid guiding pipe 15 into the fluid - actuated control assembly 38 via each of the modules 19, 23, 25 (for example, the interface module 19, the high - flow module 23 and the low - flow module 25 in the example of Figure 2 ). For this purpose, each of the modules 19, 23, 25 may include one or more pipes ( Figure 2 not shown in Figure 2(not shown in []) for guiding fluid from the fluid motor fluid discharge port 18 to the fluid-actuated control assembly 38.

[0055] In addition, although Figure 2 the example of the drive part group 20 of [] includes a single drive part 22, it is also conceivable that many other embodiments of the tractor 10 may include a plurality of drive parts ( Figure 2 (not shown in []). By way of example only, it is conceivable that an embodiment of the tractor 10 may include a drive part group 20 that includes two drive parts (not shown), which are, for example, a first drive part and a second drive part. Looking from the fluid flow direction from the fluid guiding pipe 15 to the second drive part, the first drive part is located between the fluid guiding pipe 15 and the fluid motor fluid inlet 16, and the second drive part is located downstream of the fluid motor fluid discharge port 18.

[0056] Regarding the fluid-actuated control assembly 38, reference is made to Figures 3a - 3d which shows a part of an embodiment of the fluid-actuated control assembly 38. A part of the fluid-actuated control assembly 38 using the first drive part 22 is used as an example to illustrate the Figures 3a - 3d embodiment in []. However, Figures 3a - 3d the embodiment in [] can be used for any fluid-actuated control assembly of the tractor 10.

[0057] As Figures 3a - 3d shown, the control assembly 38 may include a fluid-controlled actuator group 42 such that each propulsion member in the propulsion member group is connected to a corresponding fluid-controlled actuator in the fluid-controlled actuator group. Figures 3a - 3d shows a single fluid-controlled actuator 44, which is formed as part of the fluid-controlled actuator group 42 and is adapted to control a single propulsion member 12 in the propulsion member group 34 associated with the first drive part 22.

[0058] However, it is also conceivable that other embodiments of the fluid-actuated control assemblies 38, 40 may include a fluid-controlled actuator adapted to jointly control two or more propulsion members in the propulsion member group 34.

[0059] In Figures 3a - 3d the embodiment shown, the fluid-controlled actuator 44 includes a fluid cylinder 48 with a piston 50 and a piston chamber 52.

[0060] In Figures 3a - 3dOnce again, a single fluid-controlled actuator 44 is used as an example, and each fluid-controlled actuator 44 in the fluid-controlled actuator group 42 is adapted to increase the maximum distance 54 in a direction perpendicular to the axis of rotation 30 of the drive shaft 26 (see Figure 2 ) between the drive shaft 26 and the corresponding propulsion member 12 in the propulsion member group 34 when the fluid pressure supplied to the fluid-controlled actuator 44 is equal to or higher than a fluid control pressure threshold. For this purpose, by way of example only, the propulsion member 12 may include a hub 55 adapted to be connected to the drive shaft 26. Thus, the maximum distance 54 may correspond to the distance from the center of the hub 55 to a portion of the corresponding propulsion member 12.

[0061] For this purpose, reference is made to Figure 3a and Figure 3b . In Figure 3a , the fluid-controlled actuator 44 is in a retracted state, in which the maximum distance 54 is relatively small. However, in Figure 3b , the fluid-controlled actuator 44 is in an extended / unfolded state, in which the maximum distance 54 is greater than the maximum distance in Figure 3a . Figure 3b The state of the fluid-controlled actuator 44 shown in

[0062] is obtained by supplying fluid to the piston chamber 52, thereby causing the fluid-controlled actuator 44 to unfold / extend. Figure 3c By way of example only, as shown in Figure 3c , for at least one drive part, preferably each drive part, in the drive part group, each propulsion member 12 in the propulsion member group includes a propulsion member contact portion 56 adapted to contact the inner surface 58 of the traction device in the cylindrical body 60. The maximum distance 54 from the drive shaft 26 to the propulsion member 12 constitutes the distance from the drive shaft 26 to the propulsion member contact portion 56 in a direction perpendicular to the axis of rotation 30 of the drive shaft 26. This is shown using a single propulsion member 12 in

[0063] Thus, when the maximum distance 54 is relatively small, for example in the state of Figure 3a , there may be no contact between the propulsion member 12 and the inner surface 58 of the cylindrical body 60 (the cylindrical body 60 is shown in Figure 3c ). Therefore, even when the propulsion member 12 rotates about the axis of rotation 30, this rotation does not generate a propulsion force between the traction device 10 and the cylindrical body 60.

[0064] However, when the maximum distance 54 is relatively large, for example in Figure 3b and Figure 3cIn the state of , contact is established between the propulsion member 12 and the inner surface 58 of the cylindrical body 60. Thus, when the propulsion member 12 rotates about the rotation axis 30, this rotation generates a propulsion force between the tractor 10 and the cylindrical body 60.

[0065] In other words, Figures 3a - 3d the fluid-controlled actuator 44 in the embodiment can be used to control whether contact should be established between the propulsion member 12 and the inner surface 58 of the cylindrical body 60.

[0066] In addition, but by way of example only, Figures 3a - 3d it is shown that the control assembly may include a biasing device 62 adapted to bias each propulsion member 12 in the propulsion member group 34 towards a position having a minimum maximum distance 54 from the drive shaft 26 in a direction perpendicular to the rotation axis 30 of the drive shaft 26. In Figures 3a - 3d the embodiment, the biasing device 62 is illustrated by a single biasing member such as a spring, which is adapted to bias a single propulsion member 12 in the propulsion member group 34 towards a position having a minimum maximum distance 54 from the drive shaft 26 in a direction perpendicular to the rotation axis 30 of the drive shaft 26. However, in many other embodiments of the control assembly, the biasing device 62 may include one or more biasing members adapted to bias two or more propulsion members towards a position where each propulsion member has a minimum maximum distance 54.

[0067] In addition, as Figures 3a - 3d shown, for at least one drive part, preferably each drive part in the drive part group, each propulsion member 12 in the propulsion member group includes a rim 64 around the drive shaft 26. Preferably, each propulsion member in the propulsion member group includes a wheel 65, and the wheel 65 in turn includes a rim 64. By way of example only, as Figure 3a and 3b shown, the rim 64 may be pivotally connected to the hub 55 via a pivot connection point 66, which may include, for example, a rotating bolt. In addition, for example, as Figure 3a shown, the propulsion member 12 may include a friction member 68 surrounding the rim 64 in a circumferential direction. By way of example only, the friction member 68 may be referred to as a tire. As a non-limiting example, a bearing 70 may be located between the rim 64 and the friction member 68.

[0068] Thus, but by way of example only, when the pressure in the piston chamber 52 increases, the piston 50 will be pushed along the piston chamber 52, whereby the rim 64 will rotate about the pivot connection point 66 such that the hub 55 and the rim 64 will become eccentric, as shown in Figure 3b and Figure 3c shown. As Figure 3cAs shown, the friction member 68 will press against the inner surface 58 of the cylindrical body 60 and create a frictional connection at the friction member contact portion 56. The bearing 70 allows the friction member 68 to rotate freely on the rim 64.

[0069] From the above, it can be understood that each of the propulsion members 12 in the propulsion member group includes a rim 64. The control assembly can be adapted to control the eccentricity of the rim 64 of each propulsion member relative to the drive shaft 26, thereby controlling the maximum distance 54 from the drive shaft 26 to each propulsion member 12 in the propulsion member group in a direction perpendicular to the axis of rotation 30 of the drive shaft 26.

[0070] As described above, Figure 3c The propulsion member 12 is shown with its rim 64 in an eccentric state such that the propulsion member contact portion 56 of the friction member 68 contacts the inner surface 58 of the cylindrical body 60. Thus, the rim 64 will exert a force on the portion of the friction member 68 that will contact the inner surface 58 of the cylindrical body 60.

[0071] When the drive shaft 26 rotates about its axis of rotation 30, the rim 64 will rotate with the drive shaft 26. Since a bearing 70 is provided between the rim 64 and the friction member 68, the rim 64 will then exert a force on another portion (adjacent to the previous portion) of the friction member 68, and said another portion will then contact the inner surface 58 of the cylindrical body 60. In this way, the rotation of the drive shaft 26 and thus the rotation of the rim 64 will cause the contact point between the friction member 68 and the inner surface 58 of the cylindrical body 60 to extend / propagate along the circumferential direction of the friction member 68. Due to the fact that the propulsion member 12 is inclined relative to the drive shaft, as will be described in detail below, the above-mentioned extension and propagation of the contact point will generate a frictional force that can be substantially parallel to the axis of rotation 30, thereby obtaining a propulsion force that is substantially parallel to the axis of rotation 30. In addition, the inclined propulsion member 12 and the propagated contact force as described above will cause the contact between the friction member 68 and the inner surface 58 of the cylindrical body 60 to form a helical path along the inner surface 58.

[0072] For this purpose, Figure 3d A side view of the propulsion member 12 is shown. As Figure 3d shown, the propulsion member 12 can be inclined relative to the drive shaft 26. Thus, as Figure 3d shown, the rim 64 can extend in the rim plane 71 (see Figure 3d ), and the rim plane 71 can form a rim angle β with the axis of rotation 30 of the drive shaft 26. From Figure 3dIt can be understood that the rim plane 71 can actually form two angles with the axis of rotation 30, namely, a first angle from the rim plane 71 towards the right side of the rim plane 71 to reach the axis of rotation 30 and a second angle from the rim plane 71 towards the left side of the rim plane 71 to reach the axis of rotation 30. As used herein, as Figure 3d shown, the rim angle β relates to the minimum angle from the rim plane 71 to the axis of rotation 30 of the drive shaft 26. As Figure 3d shown, the rim angle β is less than 90°, such that the propulsion member 12 can be regarded as being inclined relative to the drive shaft 26. By way of example only, the rim angle β can be less than 88°, preferably less than 85°.

[0073] As a number of other non-limiting examples, the rim angle β can be greater than 45°, preferably greater than 65°, more preferably greater than 75°.

[0074] As a non-limiting example, the tractor 10 can be configured such that the rim angle β of each propulsion member 12 is adjustable. As a non-limiting option, the tractor can include one or more adjustable members (not shown), such as bolts, etc., by means of which the rim angle β can be set. As another non-limiting alternative, the fluid-actuated control assembly 38 can also have the ability to adjust the rim angle β of each propulsion member 12.

[0075] The above characteristics of the rim plane 71 and the rim angle β can apply to each propulsion member 12.

[0076] It should be noted that the fluid-actuated control assembly 38 can be implemented in a variety of ways to replace or supplement the embodiments described above with reference to Figures 3a - 3d given. For this purpose, but by way of example only, reference is made to Figure 4a which shows a part of another embodiment of the fluid-actuated control assembly 38.

[0077] Figure 4a An example with a propulsion member group 34 is shown. For clarity, in this example, a single propulsion member 12 in the propulsion member group 34 associated with the first drive part 22 is shown. In Figure 4a the example, the propulsion member 12 is implemented as a roller / roller wheel, and the roller is adapted to rotate about the axis of rotation 30 of the drive shaft 26 of the first drive part 22. In addition, as Figure 4a shown, the fluid-controlled actuator 44 can control the maximum distance 54 from the drive shaft 26 to the corresponding propulsion member 12 in a direction perpendicular to the axis of rotation 30 of the drive shaft 26. In Figure 4a the fluid-controlled actuator 44 is implemented as a fluid cylinder. As shown by the double arrows in Figure 4a the maximum distance 54 can be changed by actuating the fluid-controlled actuator 44.

[0078] Additionally, but by way of example only, Figure 4a it is shown that the control assembly may include a biasing device 62 adapted to bias each of the propulsion members 12 in the propulsion member group 42 towards a position having a minimum maximum distance 54 from the drive shaft 26 in a direction perpendicular to the axis of rotation 30 of the drive shaft 26. In Figure 4a an embodiment, the biasing device 62 is illustrated by a single biasing member such as a spring, the single biasing member being adapted to bias a single propulsion member 12 in the propulsion member group 42 towards a position having a minimum maximum distance 54 from the drive shaft 26 in a direction perpendicular to the axis of rotation 30 of the drive shaft 26.

[0079] The maximum distance 54 from the drive shaft 26 to the propulsion member 12 is the distance from the drive shaft 26 to the propulsion member contact portion 56 in a direction perpendicular to the axis of rotation 30 of the drive shaft 26.

[0080] By way of example only, Figure 4a the propulsion member contact portion 56 in [[]] may include a roller adapted to rotate about a roller axis of rotation 73, wherein the roller axis of rotation 73 forms an angle in the range of 30° to 80° with the axis of rotation 30 of the drive shaft 26. Alternatively, Figure 4a the fluid-controlled actuator 44 in [[]] or any other connector connecting the drive shaft 26 to the propulsion member 12 may be tilted relative to the drive shaft 26 in a manner similar to that described above with reference to Figure 3d shown. Thus, rotation of the drive shaft 26 about the axis of rotation 30 will generate a propulsion force in a manner similar to that described above with reference to Figure 3c and Figure 3d described.

[0081] From Figures 3a - 3d and Figure 4a the embodiments, it can be appreciated that the fluid-actuated control assembly 38 formed as part of the drive portion 22 can be implemented in a variety of different ways.

[0082] However, regardless of the actual implementation of the fluid-actuated control assembly 38, the fluid-actuated control assembly 38 is adapted to control the maximum distance 54 from the drive shaft 26 to each of the propulsion members in the propulsion member group 34 in a direction perpendicular to the axis of rotation 30 of the drive shaft 26.

[0083] Additionally, but by way of example only, and as Figures 3a - 3d and Figure 4aAs shown in each of the embodiments, for at least one drive part 22 in the drive part group 20, preferably each drive part, each propulsion member 12 in the propulsion member group 34 is adapted to transfer a force from the inner surface 58 of the cylindrical body 60 to the drive shaft 26 when the maximum distance 54 is equal to or greater than the maximum distance threshold. As a non-limiting example, the contact between the propulsion member 12 and the inner surface 58 of the cylindrical body 60 may cause a resultant force to be applied to the propulsion member 12 and transferred to the drive shaft 26, which resultant force includes, for example, a contact force component and a friction force component.

[0084] As can be understood from the above, by way of example only, the maximum distance threshold may depend on the diameter of the cylindrical body 60.

[0085] Furthermore, by way of example only, and as also shown in Figures 3a - 3d and Figure 4a each embodiment, for at least one drive part 22 in the drive part group 20, preferably each drive part, each propulsion member 12 in the propulsion member group 34 is such that when the drive shaft 26 rotates about the axis of rotation 30 and the propulsion member 12 transfers a force from the inner surface 58 of the cylindrical body 60 to the drive shaft 26, a propulsion force is applied to the tractor 10.

[0086] Here, it should also be noted that, by way of example only, for at least one drive part 22 in the drive part group 20, preferably each drive part, each propulsion member 12 is such that: when the drive shaft 26 rotates about the axis of rotation 30 and the propulsion member 12 transfers a force from the inner surface 58 of the cylindrical body 60 to the drive shaft 26, the contact point between the propulsion member 12 and the inner surface 58 of the cylindrical body 60 will change as the drive shaft 26 rotates about the axis of rotation 30, such that the locus 79 of subsequent contact points will form a spiral shape on the inner surface 58 of the cylindrical body 60. Such a spiral shape is shown in Figure 4b . It should be noted that Figure 4b the spiral shape shown in Figures 3a - 3d and Figure 4a can be obtained by a variety of different embodiments of the propulsion member 12, for example by any of the embodiments given above with reference to

[0087] Furthermore, referring to Figure 5 , each drive part 22 in the drive part group 20 includes a fluid pressure gate assembly 72, which is adapted to allow fluid guided via the fluid guiding pipe 15 (see 离开 ) to be supplied to the fluid actuated control assembly 38 only when the pressure P Figure 2 of the fluid leaving the fluid pressure gate assembly 72 is within a predetermined pressure range.

[0088] AsFigure 5 As shown, the fluid motor 14 includes a fluid motor fluid inlet 16 and a fluid motor fluid discharge port 18. In addition, Figure 5 An embodiment is shown in which a fluid pressure gate assembly 72 is in fluid communication with the fluid motor fluid discharge port 18 such that at least a portion of the fluid pressure gate assembly 72 is adapted to receive fluid from the fluid motor fluid discharge port 18. As a non-limiting example, the fluid motor fluid discharge port 18 may be in fluid communication with at least a portion of the fluid pressure gate assembly 72 via a conduit assembly 74 that includes one or more conduits. By way of example only, the conduit assembly 74 may include a conduit portion that is formed as part of the interface module 19 as described above with reference to Figure 2 the interface module 19.

[0089] By way of example only, the predetermined pressure range may be within a range from a low pressure limit P 低 to a high pressure limit P 高 As a non-limiting example, the low pressure limit P 低 may be greater than 0 bar of relative pressure, preferably greater than 100 bar of relative pressure. In other words, the low pressure limit P 低 may be greater than 0 bar relative to the pressure environment of the tractor 10, preferably greater than 100 bar relative to the pressure environment of the tractor 10. As another non-limiting example, the low pressure limit P 低 may be greater than 1 bar of absolute pressure, preferably greater than 100 bar, more preferably greater than 200 bar.

[0090] In addition, again by way of example only, the high pressure limit P 高 may be equal to or less than 10 times the low pressure limit P 低 , preferably equal to or less than 5 times the low pressure limit P 低 , more preferably equal to or less than 2 times the low pressure limit P 低 .

[0091] Figure 5 An exemplary embodiment of the fluid pressure gate assembly 72 is also shown. As Figure 5 shown, the fluid pressure gate assembly 72 may include a first pressure reducing valve 76 that is adapted to: allow fluid to pass through the first pressure reducing valve 76 when the fluid pressure acting on the first pressure reducing valve 76 is equal to or exceeds a first pressure reducing valve pressure threshold, thereby preventing fluid from being supplied to the fluid actuated control assembly 38. Preferably, as Figure 5 shown in the embodiment of Figure 5 , the first pressure reducing valve 76 may be adapted to: allow fluid to flow via the first pressure reducing valve 76 to the ambient environment of the tractor 10 when the fluid pressure acting on the first pressure reducing valve 76 is equal to or exceeds the first pressure reducing valve pressure threshold, as indicated by the arrow 78 in

[0092] As a non-limiting example, as Figure 5 shown, the first pressure reducing valve 76 may include a first pressure reducing valve inlet 80, and the first pressure reducing valve 76 may be adapted to: when the fluid pressure acting on the first pressure reducing valve inlet 80 is equal to or exceeds the first pressure reducing valve pressure threshold, allow fluid to pass through the first pressure reducing valve 76, thereby preventing fluid from being supplied towards the fluid-actuated control assembly 38.

[0093] In addition, the first pressure reducing valve 76 may be adapted to: when the fluid pressure acting on the first pressure reducing valve 76, for example when the fluid pressure acting on the first pressure reducing valve inlet 80 as described above is lower than the first pressure reducing valve pressure threshold, prevent fluid from passing through the first pressure reducing valve 76.

[0094] Merely by way of example, and also as Figure 5 shown, the fluid pressure gate assembly 72 may include a second pressure reducing valve 82, and the second pressure reducing valve is adapted to: when the fluid pressure acting on the second pressure reducing valve 82 is equal to or exceeds the second pressure reducing valve pressure threshold, allow fluid to flow towards the fluid-actuated control assembly 38 through the second pressure reducing valve 82. As a non-limiting example, as Figure 5 shown, the second pressure reducing valve 82 may include a second pressure reducing valve inlet 84, and the second pressure reducing valve 82 may be adapted to: when the fluid pressure acting on the second pressure reducing valve inlet 84 is equal to or exceeds the second pressure reducing valve pressure threshold, allow fluid to flow towards the fluid-actuated control assembly 38 through the second pressure reducing valve 82.

[0095] In addition, merely by way of example, the fluid pressure gate assembly 72 may include a pilot pressure-operated control valve 77. Merely by way of example, the pilot pressure-operated control valve 77 may be adapted to: in the case of high fluid pressure, for example when the fluid pressure is equal to or higher than the first pressure reducing valve pressure threshold, prevent fluid from being supplied towards the second pressure reducing valve 82.

[0096] In addition, referring again to Figure 5 , but merely by way of example, at least one drive part 22 in the drive part group 20 (see Figure 2 ), preferably each drive part includes a booster 86, and looking from the flow direction from the fluid pressure gate assembly 72 to the fluid-actuated control assembly 38, the booster is located between the fluid pressure gate assembly 72 and the fluid-actuated control assembly 38.

[0097] As Figure 5 shown, the booster 86 includes a booster inlet 88 and a booster outlet 90. The booster 86 is such that: in use, the fluid leaving the booster outlet 90 has a higher pressure than the fluid entering the booster inlet 88. Preferably, the booster 86 is adapted to be powered by the fluid entering the booster inlet 88.

[0098] In addition, by way of example only, the supercharger 86 may also include a supercharger discharge port 92. By way of example only, the supercharger discharge port 92 may be adapted to discharge fluid into the surroundings of the tractor 10. Thus, but by way of example only, the supercharger 86 may be such that: when in use, the fluid leaving the supercharger outlet 90 has a lower mass flow rate than the fluid entering the supercharger inlet 88.

[0099] In addition, as Figure 5 shown by way of non-limiting example, the fluid pressure gate assembly 72 may include an internal throttling device 94 adapted to throttle the fluid flow from the first pressure reducing valve 76 to the second pressure reducing valve 82. Preferably, the internal throttling device 94 may be an adjustable internal throttling device.

[0100] In addition, by way of example and as also Figure 5 shown, the fluid pressure gate assembly 72 may include a fluid pressure gate assembly discharge port 96 located upstream of the second pressure reducing valve 82. In addition, the fluid pressure gate assembly 72 may include a discharge port throttling device 98 adapted to throttle the fluid flow towards the fluid pressure gate assembly discharge port 96. Preferably, the discharge port throttling device 98 may be an adjustable discharge port throttling device.

[0101] Thus, fluid that reaches the second pressure reducing valve 82 but does not have a pressure high enough to pass through the second pressure reducing valve 82 may be discharged via the fluid pressure gate assembly discharge port 96.

[0102] By way of example only, the first pressure reducing valve 76 and the second pressure reducing valve 82 may be arranged in different modules. Thus, with reference to Figure 5 and Figure 2 , the first pressure reducing valve 76 may be formed as part of the high flow rate module 23, and the second pressure reducing valve 82 may be formed as part of the low flow rate module 25. In addition, as Figure 2 shown, the high flow rate module 23 and the low flow rate module 25 may be separate components adapted to be releasably connected to each other.

[0103] It can be appreciated from the foregoing and Figure 5 that the mass flow rate of the fluid leaving the high flow rate module 23 may be higher than the mass flow rate of the fluid leaving the low flow rate module 25, hence the use of the terms "high flow rate module" and "low flow rate module" respectively. In addition, it can be appreciated from the foregoing that the pressure of the fluid leaving the high flow rate module 23 may be lower than the pressure of the fluid leaving the low flow rate module 25. Thus, the high flow rate module may alternatively be referred to as a low pressure module, and the low flow rate module 25 may alternatively be referred to as a high pressure module.

[0104] Furthermore, as a non-limiting example, at least one drive part 22 in the drive part group 20, preferably each drive part, includes a fluid-actuated control component discharge port 102 which, when viewed in the flow direction from the fluid pressure gate assembly 72 to the fluid-actuated control component 38, is located downstream of the fluid-actuated control component 38. Preferably, the fluid-actuated control component discharge port 102 is adapted to discharge fluid into the surroundings of the tractor 10.

[0105] By way of example only, the tractor 10 can be formed as part of an apparatus 104 that includes, for example, a tool 106 and the tractor 10, also see the description below with reference to Figure 7a By way of example only, as Figure 5 shown, the tool 106 can be adapted to receive fluid from the fluid-actuated control component discharge port 102 of at least one drive part 22 in the drive part group 20. In fact, in the example of Figure 5 the tool 106 is adapted to receive fluid from the fluid-actuated control component discharge port 102 of a single drive part 22 presented in the example of Figure 5 .

[0106] It should be noted that Figure 5 is only used as an example of the tractor 10 according to the present disclosure. To this end, Figure 6a another embodiment of the tractor 10 is shown. As can be seen from Figure 6a , the embodiment of the tractor 10 shown in the figure includes a fluid motor 14. The tractor also includes a fluid guiding pipe 15 adapted to guide fluid to the fluid motor 14. The tractor 14 also includes a drive part group that includes at least one drive part 22. For Figure 5 , Figure 6a the example includes a single drive part 22, but embodiments of the tractor can also be envisaged that include two or more drive parts. Regardless of the number of drive parts, each drive part 22 in the drive part group 20 includes the features given below.

[0107] Each drive part 22 in the drive part group 20 includes a drive shaft 26 which is connected to the fluid motor 14, whereby the drive shaft is adapted to rotate about the axis of rotation 30 of the drive shaft 26.

[0108] Each drive part 22 in the drive part group 20 includes a propulsion member group 34 which includes at least one propulsion member 12, preferably two or more propulsion members 12, and each propulsion member 12 in the propulsion member group 34 is non-rotatably fixed to the drive shaft 26.

[0109] Each drive section 22 in the drive section group 20 includes a fluid-actuated control assembly 38 adapted to control the maximum distance 54 from the drive shaft 26 to each propulsion member 12 in the propulsion member group 34 in a direction perpendicular to the axis of rotation 30 of the drive shaft 26.

[0110] In addition, each drive section 22 in the drive section group 20 includes a fluid pressure gate assembly 72 adapted to allow fluid directed via the fluid guiding conduit 15 to be supplied to the fluid-actuated control assembly 38 only if the pressure of the fluid exiting the fluid pressure gate assembly 72 is within a predetermined pressure range.

[0111] The fluid pressure gate assembly 72 can be implemented in a variety of different ways to ensure that it is adapted to allow fluid directed via the fluid guiding conduit 15 to be supplied to the fluid-actuated control assembly 38 only if the pressure of the fluid exiting the fluid pressure gate assembly 72 is within a predetermined pressure range. For example, the fluid pressure gate assembly 72 can include a single pressure reducing valve adapted to allow fluid to pass through the single pressure reducing valve only if the pressure of the fluid exiting the single pressure reducing valve is within a predetermined pressure range.

[0112] However, Figure 6b A preferred embodiment of the fluid pressure gate assembly 72 including a first pressure reducing valve 76 and a second pressure reducing valve 82 is shown. The arrangement and characteristics of the first pressure reducing valve 76 and the second pressure reducing valve 82 have been described above with respect to Figure 5 and will not be repeated here.

[0113] In addition, as Figure 6a shown, each drive section 22 in the drive section group 20 can include a booster 86 located between the fluid pressure gate assembly 72 and the fluid-actuated control assembly 38. In addition, Figure 6a An optional feature is schematically shown, namely that at least one drive section 22 in the drive section group 20, preferably each drive section, can include a fluid-actuated control assembly discharge port 102 located downstream of the fluid-actuated control assembly 38.

[0114] Regardless of the embodiment of the tractor 10, the fluid guiding conduit 15 (see, for example, above with respect to Figure 2 , Figure 5 or Figure 6aEach of the embodiments given in any of the above (each of the embodiments) may include at least one of the following or may be constituted by at least one of the following: coiled tubing or a threaded drill string assembly. As described above, when the tractor 10 is advanced by means of the propulsion member 12, the tractor 10 may be imparted with torque. The coiled tubing or the threaded drill string assembly may provide a reaction torque that may reduce the risk of the tractor rotating relative to the cylindrical body ( Figure 2 , Figure 5 or Figure 6a not shown therein) during use.

[0115] Turning to Figure 7a , the non-limiting embodiment shown therein shows that the cylindrical body 60 has a longitudinal extent / length in the longitudinal direction 108 of the cylindrical body. The tractor 10 is adapted to advance the device 104 in a direction parallel to and / or coaxial with the longitudinal direction 108 of the cylindrical body. In Figure 7a 's example, the device 104 includes a tractor 10 and a tool 106. However, in a number of other embodiments, as an alternative or supplement to the tool 106, the device 104 may include a sensor.

[0116] Furthermore, as Figure 7a shown, for at least one drive part 22 in the drive part group, preferably each drive part, when in use, the axis of rotation 30 of the drive shaft 26 and the longitudinal direction 108 of the cylindrical body form an angle with an absolute value less than 10°. Preferably, as Figure 7a shown, the axis of rotation 30 of the drive shaft 26 is parallel and / or coaxial with the longitudinal direction 108 of the cylindrical body.

[0117] Furthermore, Figure 7a and Figure 7b show an embodiment in which the propulsion member group 34 includes a propulsion member 12, each propulsion member having a rim 64 around the drive shaft 26 (see also, for example, Figure 3a ), such that the fluid-actuated control assembly 38 is adapted to control the eccentricity of the rim 64 relative to the drive shaft, thereby controlling the maximum distance 54 (see Figure 3a ) from the drive shaft 26 to each propulsion member 12 in the propulsion member group 34 in a direction perpendicular to the axis of rotation 30 of the drive shaft 26. For easier identification of the drive shaft 26 and the axis of rotation 30, Figure 7b the tool 106 is not shown.

[0118] Figure 7a shows the tractor 10 in a state in which the propulsion member 12 has a small maximum distance 54 (see Figure 3a ), i.e., a small eccentricity, such that the propulsion member 12 does not contact the inner surface 58 of the cylindrical body 60. However, in Figure 7bIn the state of Figure 3b , each propulsion member 12 has a relatively large maximum distance 54 (see Figure 7b ), that is, a relatively large eccentricity, such that the propulsion member 12 contacts the inner surface 58 of the cylindrical body 60. Thus, when the propulsion member 12 is in the state shown in

[0119] and the drive shaft 26 rotates about the rotation axis 30, the propulsion member 12 will impart a propulsion force to the tractor 10 that is at least substantially parallel to the longitudinal direction 108 of the cylindrical body and / or coaxial therewith. Figure 7c Although Figure 7c is a cross-sectional view of the tractor 10, Figure 7b shows the tractor 10 in the same state as in Figure 7c . Thus,

[0120] Figure 7a also shows a second aspect of the present disclosure, which relates to a tractor assembly 110 including the tractor 10, wherein the fluid guiding pipe 15 is non-rotatably fixed to a part of the tractor 10. In the embodiment of Figure 7a , the fluid guiding pipe 15 is non-rotatably fixed to a part of the fluid motor 14 of the tractor 10.

[0121] The tractor assembly 110 further includes a fluid guiding pipe rotation lock 112, which is adapted to prevent a part of the fluid guiding pipe 15 from rotating relative to a part of the cylindrical body 60. The fluid guiding pipe rotation lock 112 can be implemented in a variety of different ways, for example, by means of a cover (not shown) or the like, which is adapted to be fixed to the cylindrical body 60 so as to thereby close the end opening of the cylindrical body and prevent relative movement between the fluid guiding pipe 15 and the cover, and so as to thereby prevent a part of the fluid guiding pipe 15 from rotating relative to a part of the cylindrical body 60. Advantageously, the fluid guiding pipe rotation lock 112 can be used in such embodiments of the tractor 10 and / or the tractor assembly 110, that is, in which the fluid guiding pipe 15 includes at least one of the following or consists of at least one of the following: coiled tubing or a threaded drill string set. This is because the combination of the fluid guiding pipe rotation lock 112 and the coiled tubing and / or the threaded drill string set can provide a suitably high torque, which can counteract the torque acting on the tractor during the propulsion of the tractor 10.

[0122] In addition, as described above, a third aspect of the present disclosure relates to an apparatus 114 including a sensor 106 and / or a tool 106 and a tractor 10 according to the first aspect of the present disclosure or a tractor assembly 110 according to the second aspect of the present disclosure.

[0123] Figure 7aSensor 106 or tool 106 is schematically shown. As a non - limiting example, the tool can be a jet nozzle or a fluid - actuated tool. Additionally, again by way of non - limiting example only, sensor 106 can be, for example, a sensor for measuring at least one of the following: temperature, fluid flow, torque, pressure, and humidity. Sensor 106 and / or tool 106 can be fixedly or releasably connected to the tractor 10. By way of example only, sensor 106 and / or tool 106 can be connected to the tractor 10 by means of a bolted joint (not shown).

[0124] A fourth aspect of the present disclosure relates to a cylindrical body assembly 116 that includes a cylindrical body 60 and a tractor 10 according to the first aspect of the present disclosure, a tractor assembly 110 according to the second aspect of the present disclosure, or a device 114 according to the third aspect of the present disclosure.

[0125] In addition, a counter - gear / reversing gear as exemplified in Figure 8 can be employed on the tractor 10 to keep the torque of the entire assembly to a minimum and prevent any additional torque forces from acting on the device or to eliminate the rotation of the device. The teeth 118 and the shaft 120 of the counter - gear are shown in the figure.

[0126] In another aspect, as Figure 9 shown, one or more knuckle joints 122 can be added as an interface to the tractor 10 to increase the flexibility of the device in moving through curved and curvilinear sections. Cross - sections 124, 126 depict the front surface and the inner surface of the knuckle joint 122 that can interface with the connection interface of the tractor 10. To this end, Figure 10 an embodiment of the tractor 10 is shown in which two drive portions 22, 24 are connected to each other via a knuckle joint 122.

[0127] Figure 11 Shows how the modular construction of the tractor 10 and / or the device 104 according to the present invention enables different configurations. Configuration A is a tractor with two wheel modules with small wheels, which is suitable for narrow wells or pipelines. Configuration B is similar to Configuration A, but larger wheels are selected here. Configuration C has a greater number of wheels than Configurations A and B. Configuration D includes three wheel modules. Configurations E and F have a knuckle joint between two wheel modules, thus making these configurations suitable for traveling through bends, sharp turns, and restricted sections where the flexibility of the tractor is required.

[0128] As a non - limiting alternative, the present disclosure can be presented according to any one of the following scenarios. To this end, it should be noted that, by way of example only, the above - mentioned tractor 10 can alternatively be referred to as a modular fluid - operated device 10, for example.

[0129] Solution 1. A modular fluid-operated device 10 for propulsion and operation inside a cylindrical body such as a pipe, the modular fluid-operated device comprising:

[0130] - A fluid motor 14;

[0131] - An interface module 19 connected to the fluid motor;

[0132] - At least one flow module 21; and

[0133] - At least one drive module 34,

[0134] wherein these modules include connecting means and are configured to be releasably connected in series with each other.

[0135] Solution 2. The modular fluid-operated device according to Solution 1, wherein there are two flow modules 21, namely: a low-flow module 25 and a high-flow module 23.

[0136] Solution 2. The modular fluid-operated device according to Solution 2, wherein the low-flow module 23 is connected to the interface module, and the high-flow module 23 is connected between the low-flow module and the drive module.

[0137] Solution 4. The modular fluid-operated device according to Solution 1 or 2, wherein the drive module includes a certain number of / multiple wheels that provide propulsion force for the device.

[0138] Solution 5. The modular fluid-operated device according to any one of Solutions 2-4, wherein the low-flow module is configured to receive a small flow of fluid from the high-flow module and supply pressurized fluid to the drive module 34.

[0139] Solution 6. The modular fluid-operated device according to any one of the foregoing solutions, wherein at least one drive module 34 includes a first wheel module and a second wheel module, each drive module includes a certain number of / multiple wheels, wherein the wheels 12 in the first wheel module rotate in one direction, and the wheels in the second wheel module rotate in the opposite direction relative to the wheels in the first wheel module.

[0140] Solution 7. The modular fluid-operated device according to any one of the foregoing solutions, wherein the interface module includes a rotating device to allow the fluid motor to rotate relative to the modules of the device.

[0141] Solution 8. The modular fluid-operated device 10 according to any one of the foregoing solutions, further comprising a tool interface adapted to be connected to an optional tool, wherein the tool interface includes connecting means for the tool.

[0142] Aspect 9. The modular fluid-operated device 10 according to any one of the foregoing aspects includes a knuckle joint that interconnects two modules.

[0143] Aspect 10. The modular fluid-operated device 10 according to any one of Aspects 4 - 8 includes an eccentric drive that is configured to move a wheel in a radial direction relative to a central axis of one or more drive modules.

[0144] Aspect 11. The modular fluid-operated device 10 according to any one of Aspects 4 - 10 includes an emergency device that is configured to retract the wheel to a centered position around a central axis of one or more drive modules.

Claims

1. A tractor (10) for advancing a device (104) inside a cylindrical body (60), the tractor (10) comprising a fluid motor (14), the tractor (10) further comprising a fluid guiding pipe (15) adapted to guide fluid to the fluid motor (14), the tractor (10) further comprising a driving part group (20), the driving part group including at least one driving part (22), wherein each driving part (22) in the driving part group (20) comprises: - a driving shaft (26) connected to the fluid motor (14), whereby the driving shaft (26) is adapted to rotate about a rotation axis (30) of the driving shaft (26); - a propulsion member group (34) including at least one propulsion member (12), preferably two or more propulsion members, each propulsion member (12) in the propulsion member group (34) being non-rotatably fixed to the driving shaft (26); - a fluid-actuated control assembly (38) adapted to control a maximum distance (54) from the driving shaft (26) to each propulsion member (12) in the propulsion member group (34) in a direction perpendicular to the rotation axis (30) of the driving shaft (26); and - A fluid pressure gate assembly (72) adapted to: allow fluid directed via the fluid conducting conduit (15) to be supplied to the fluid actuated control assembly (38) only if the pressure (P 离开 ) of the fluid exiting the fluid pressure gate assembly (72) is within a predetermined pressure range.

2. The tractor (10) according to claim 1, wherein, The predetermined pressure range is between a low pressure limit (P 低 ) and a high pressure limit (P 高 ), and the low pressure limit (P 低 ) is greater than 0 bar of relative pressure, preferably greater than 100 bar of relative pressure.

3. The tractor (10) according to claim 2, wherein, The high pressure limit (P 高 ) is equal to or less than 10 times, preferably equal to or less than 5 times, and more preferably equal to or less than 2 times the low pressure limit.

4. The tractor (10) according to any one of the preceding claims, wherein, the fluid motor (14) includes a fluid motor fluid inlet (16) and a fluid motor fluid outlet (18), and the fluid pressure gate assembly (72) is in fluid communication with the fluid motor fluid outlet (18) such that at least a part of the fluid pressure gate assembly (72) is adapted to receive fluid from the fluid motor fluid outlet (18).

5. The tractor (10) according to any one of the preceding claims, wherein, the fluid pressure gate assembly (72) includes a first pressure reducing valve (76) adapted to: allow fluid to pass through the first pressure reducing valve (76) when the fluid pressure acting on the first pressure reducing valve (76) is equal to or exceeds the pressure threshold of the first pressure reducing valve (76), thereby preventing the fluid from being supplied to the fluid-actuated control assembly (38), preferably, the first pressure reducing valve (76) is adapted to: allow fluid to flow to the surrounding environment of the tractor (10) via the first pressure reducing valve (76) when the fluid pressure acting on the first pressure reducing valve (76) is equal to or exceeds the pressure threshold of the first pressure reducing valve (76).

6. The tractor (10) according to claim 5, wherein, The fluid pressure gate assembly (72) includes a second pressure reducing valve (82) adapted to allow fluid to flow via the second pressure reducing valve (82) to the fluid-actuated control assembly (38) when the fluid pressure acting on the second pressure reducing valve (82) is equal to or exceeds the pressure threshold of the second pressure reducing valve (82).

7. The tractor (10) according to any one of the preceding claims, wherein, at least one drive part, preferably each drive part in the drive part group (20) includes a booster (86), and when viewed in the flow direction from the fluid pressure gate assembly (72) to the fluid-actuated control assembly (38), the booster is located between the fluid pressure gate assembly (72) and the fluid-actuated control assembly (38), the booster (86) includes a booster inlet (88) and a booster outlet (90), and wherein the booster (86) is such that: in use, the fluid leaving the booster outlet (86) has a higher pressure than the fluid entering the booster inlet (88), and preferably, the booster (86) is adapted to be powered by the fluid entering the booster inlet (88).

8. The tractor (10) according to any one of the preceding claims, wherein, at least one drive part, preferably each drive part in the drive part group (20) includes a fluid-actuated control assembly discharge port (102), and when viewed in the flow direction from the fluid pressure gate assembly (72) to the fluid-actuated control assembly (38), the fluid-actuated control assembly discharge port is downstream of the fluid-actuated control assembly (38), and preferably, the fluid-actuated control assembly discharge port (102) is adapted to discharge fluid into the surrounding environment of the tractor (10).

9. The tractor (10) according to any one of the preceding claims, wherein, the fluid guiding pipe (15) comprises at least one of or consists of at least one of: coiled tubing or a threaded drill string group.

10. The tractor (10) according to any one of the preceding claims, wherein, for at least one drive part (22), preferably each drive part in the drive part group (20), each propulsion member (12) in the propulsion member group (34) includes a rim (64) around the drive shaft (26), and preferably, each propulsion member (12) in the propulsion member group (34) includes a wheel (65), and the wheel in turn includes the rim (64).

11. The tractor (10) according to claim 10, wherein, the fluid-actuated control assembly (38) is adapted to control the eccentricity of the rim (64) relative to the drive shaft (26), so as to control the maximum distance (54) from the drive shaft (26) to each propulsion member (12) in the propulsion member group (34) in a direction perpendicular to the axis of rotation (30) of the drive shaft (26).

12. The tractor (10) according to claim 10 or 11, Wherein, the rim (64) extends in a rim plane (71) which forms a rim angle (β) with the rotational axis (30) of the drive shaft (26), the rim angle being less than 90°, preferably less than 88°, more preferably less than 85°.

13. The tractor (10) according to any one of the preceding claims, wherein, for at least one drive part, preferably each drive part, in the drive part group (20), each propulsion member (12) in the propulsion member group (34) includes a propulsion member contact portion (56) adapted to contact the inner surface (58) of the cylindrical body (60), and the maximum distance (54) from the drive shaft (26) to the propulsion member (12) is the distance from the drive shaft (26) to the propulsion member contact portion (56) in a direction perpendicular to the rotational axis (30) of the drive shaft (26).

14. The tractor (10) according to any one of the preceding claims, wherein, for at least one drive part (22), preferably each drive part, in the drive part group (20), each propulsion member (12) in the propulsion member group (34) is adapted to transfer a force from the inner surface (58) of the cylindrical body (60) to the drive shaft (26) when the maximum distance (54) is equal to or greater than a maximum distance threshold.

15. The tractor (10) according to claim 14, wherein, for at least one drive part (22), preferably each drive part, in the drive part group (20), each propulsion member (12) in the propulsion member group (34) is such that: when the drive shaft (26) rotates about the rotational axis (30) and the propulsion member (12) transfers a force from the inner surface (58) of the cylindrical body (60) to the drive shaft (26), a propulsion force is applied to the tractor (10).

16. The tractor (10) according to claim 14 or 15, wherein, for at least one drive part (22), preferably each drive part, in the drive part group (20), each propulsion member (12) in the propulsion member group (34) is such that: when the drive shaft (26) rotates about the rotational axis (30) and the propulsion member (12) transfers a force from the inner surface (58) of the cylindrical body (60) to the drive shaft (26), the contact point between the propulsion member (12) and the inner surface (58) of the cylindrical body (60) will change as the drive shaft (26) rotates about the rotational axis (30), such that the locus (79) of subsequent contact points will form a spiral shape on the inner surface (58) of the cylindrical body (60).

17. The tractor (10) according to any one of the preceding claims, wherein, The cylindrical body (60) has a longitudinal extent in the longitudinal direction (108) of the cylindrical body, and the tractor (10) is adapted to propel the device (104) in a direction parallel and / or coaxial with the longitudinal direction (108) of the cylindrical body.

18. The tractor (10) according to claim 17, wherein, for at least one drive part (22), preferably each drive part, in the drive part group (20), in use, the rotational axis (30) of the drive shaft (26) forms an angle with the longitudinal direction (108) of the cylindrical body having an absolute value less than 10°, preferably, the rotational axis (30) of the drive shaft (26) is parallel and / or coaxial with the longitudinal direction (108) of the cylindrical body.

19. A tractor assembly (110) comprising a tractor (10) according to any one of the preceding claims, wherein, the fluid guiding pipe (15) is non-rotatably fixed to a part of the tractor (10), and the tractor (10) assembly further comprises a fluid guiding pipe rotation lock (112), the fluid guiding pipe rotation lock being adapted to prevent a part of the fluid guiding pipe (15) from rotating relative to a part of the cylindrical body (60).

20. A device (114) comprising a sensor (106) and / or a tool (106), and a tractor (10) according to any one of claims 1-18 or a tractor assembly (110) according to claim 19.

21. The device (104) according to claim 20, which depends on claim 8, wherein, the tool (106) is adapted to receive fluid from the fluid-actuated control component discharge port (102) of at least one of the drive parts (22) in the drive part group (20).

22. A cylindrical body (60) assembly, which comprises: a cylindrical body (60), and a tractor (10) according to any one of claims 1-18, a tractor assembly (110) according to claim 19, or a device (104) according to any one of claims 20-21.

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