SYSTEM FOR TRACTION INSIDE PIPES, WITH FLEXIBLE RESERVOIR AND WITH MOTORIZED PUMP FOR HYDRAULIC POWER

Abstract

The present invention provides a pulling system essentially consisting of two sets of feet (11) and a hydraulic cylinder (15). Each set is positioned on one of the sides of the hydraulic cylinder (15). The two sets of feet (11) have a self-locking mechanism. The self-locking mechanism allows each set of feet to act preferentially on one side and exert powerful forces. The invention further provides a flexible reservoir (21) capable of equalizing the pressures inside and outside the medium, allowing the operation of a hydraulic system in an environment that is subjected to any pressure value, provided that it is within the operating range of the components. In addition, the maintenance of a closed circuit ensures that no fluid contamination occurs.

Claims

1- System for traction inside pipelines, wherein it comprises at least one front traction module (02), at least one motor pump assembly (05), at least one manifold (06), at least two leg sets (11), at least one auxiliary cylinder (12), at least one main hydraulic cylinder (15), at least one umbilical, at least one electric motor (22), at least one hydraulic pump (23), and at least one support structure (26).

2- System for traction inside pipelines, according to claim 1, wherein it has a flexible reservoir (21) to keep the hydraulic oil separate from the medium and to balance the pressure in the reservoir with the pressure in the medium.

3- System for traction inside pipelines, according to claim 1, wherein it has an auxiliary tool (04) for carrying out other operations.

4- System for traction inside pipelines, according to claim 1, wherein the motor pump set (05) drives the main hydraulic cylinder (15) and the auxiliary cylinders (12).

5- System for traction inside pipelines, according to claim 1, wherein the motor pump set (05) receives electrical energy through the umbilical cable and transforming it into hydraulic power.

6- System for traction inside pipelines, according to claim 1, wherein it has at least one manifold (06) that directs the hydraulic fluid to one side of the main cylinder (15) or to the auxiliary cylinders (12).

7- System for traction inside pipelines, according to claim 1, wherein it has a front traction module (02) and a rear traction module (07).

8- System for traction inside pipelines, according to claim 7, wherein the traction modules have leg sets (11) that make contact with the internal part of the pipe.

9- System for traction inside pipelines, according to claim 8, wherein the leg sets (11) have self-locking.

10- System for traction inside pipelines, according to claim 8, wherein the leg sets (11) maintain a constant angle relative to the internal surface of the pipe within a range of pipeline diameters.

11- System for traction inside pipelines, according to claim 8, wherein the leg sets (11) are opened by the auxiliary cylinders (12).

12- System for traction inside pipelines, according to claim 1, wherein the flexible couplings (13) connecting the leg sets to each other, to the tool, to the cylinder, or to other parts of the robot.

13- System for traction inside pipelines, according to claim 1, wherein the connectors (14) promote the displacement of the hydraulic fluid of the manifolds (06) to the main hydraulic cylinder (15) and to the auxiliary cylinders (12).

14- System for traction inside pipelines, according to claim 1, wherein the main hydraulic cylinder (15) is responsible for moving the front traction module (02) or rear traction module (07).

15- System for traction inside pipelines, according to claim 1, wherein the main hydraulic cylinder (15) is maintained in its course by guides (16).

16- System for traction inside pipelines, according to claim 1, wherein the hydraulic hoses is preserved with cable protectors (17).

17- System for traction inside pipelines, according to claim 2, wherein the flexible reservoir (21) is made of elastomeric material.

18- System for traction inside pipelines, according to any of claim 2 or 17, wherein the flexible reservoir (21) has connections (d) at the ends for inlet and outlet of the working fluid.

19- System for traction inside pipelines, according to any of claim 2 or 17, wherein the flexible reservoir (21) has one or more manifolds (6), responsible for actuating the hydraulic cylinders in its inside.

20- System for traction inside pipelines, according to any of claim 2 or 17, wherein the motor pump set is installed inside the flexible reservoir (21), compensating the ambient pressure.

21- System for traction inside pipelines, according to claim 1, wherein the electric motor (22) moves the hydraulic pump (23).

22- System for traction inside pipelines, according to claim 1, wherein the tensioner (24) keeps the flexible reservoir (21) tensioned.

23- System for traction inside pipelines, according to claim 22, wherein the tensioner (24) has the shape of a helical spring, plate spring or bundle of springs.

24- System for traction inside pipelines, according to claim 1, wherein the check valve (25) allows the hydraulic pumps (23) to operate independently.

25- System for traction inside pipelines, according to claim 1, wherein the structure (26) supports the pumps (23), the check valve (25) and the control valves set (27).

26- System for traction inside pipelines, according to claim 1, wherein the manifold (06) with the control valves (27) directs the hydraulic fluid to one side of the main piston, or to the auxiliary pistons of the cylinders.

27- System for traction inside pipelines, according to claim 1, wherein it has a winding module (03), responsible for compensating the movement of the hoses connected to the moving part of the piston.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be described in more detail below, with reference to the attached figures which, in a schematic and not limiting of the inventive scope, represent examples of its realization. The drawings show:

[0030] FIG. 1 illustrates an overview of the traction system of this invention;

[0031] FIG. 2 illustrates the front traction module;

[0032] FIG. 3 illustrates the rear traction module;

[0033] FIG. 4a illustrates the leg curve, constructed by joining several points through a spline. FIG. 4b shows an example of a design procedure for a 4 leg in a 4 inch tube, where (a) represents the 4 contact angle with respect to the inner surface of the pipe.

[0034] FIG. 5 illustrates in detail a motor pump module;

[0035] FIG. 6 illustrates in detail the manifolds module;

[0036] FIG. 7 illustrates the reservoir with flexible body, developed in this invention;

[0037] FIGS. 8a and 8b illustrate the flexible body reservoir concept developed in this invention. FIG. 8a illustrates the forward cylinder and FIG. 8b the backward cylinder;

[0038] FIG. 9 shows a preferred configuration for the hydraulic circuit to control the forward main cylinder and the backward main cylinder.

[0039] FIG. 10 presents a preferred configuration for the hydraulic control circuit of the auxiliary cylinders of the forward and backward system.

DETAILED DESCRIPTION OF THE INVENTION

[0040] Below follows a detailed description of a preferred embodiment of the present invention, by way of example and in no way limiting. Nevertheless, it will be clear to a person skilled in the art, from the reading of this description, possible additional embodiments of the present invention further comprised by the essential and optional features below.

[0041] The present invention proposes the use of a tool connected to a locomotion device, such as an umbilical cable connected to a robot, for carrying out operations inside pipelines, such as removing obstructions, such as hydrates or paraffins, inspection, cutting lines, equipment installation, smoothing, etc.

[0042] For large distances, the contact of the outer part of the umbilical cable with the inner surface of the pipelines causes a frictional force with a significant amplitude, which makes it difficult for the robot to move.

[0043] One of the objectives of this invention is a traction system for this robot. This device system, along with a system developed to minimize frictional forces, allows the robot to move over long distances. The traction device essentially consists of two leg sets and a hydraulic cylinder. Each set is positioned on one side of the hydraulic cylinder. Both sets have a self-locking mechanism.

[0044] The self-locking mechanism allows each leg set to preferentially act to one side and exert forces of great magnitude. Initially, one of the leg sets is moved forward by the hydraulic cylinder. This leg set attaches to the pipe and the cylinder is retracted. This brings the other leg set forward, as well as the rest of the robot and the umbilical. The leg set is designed in such a way that self-locking occurs in a similar way for a range of pipeline diameters. For this, it uses a specific curvature that allows the robot to maintain approximately the same self-locking angle.

[0045] FIG. 1 presents an overview of the traction system of this invention. This device consists of a coupling with the tool itself (01), responsible for carrying out operations inside the pipelines. It also has a front traction module (02), responsible for moving the robot forward, dragging the umbilical cable. It is also provided with a winding module (03) to compensate the displacement of the hydraulic cylinder. It may contain an auxiliary tool (04) for carrying out other activities. To drive the hydraulic cylinder, there are one or more motor pump sets (05), responsible for receiving electrical energy and transforming it into hydraulic power. Additionally, one or more manifolds (06) direct the hydraulic fluid to one side of the main cylinder, or to the auxiliary cylinder. Also, in (07) the rear traction module is represented.

[0046] FIG. 2 represents the front traction module, and FIG. 3, the rear traction module.

[0047] The robot legs (11) make contact with the inside of the pipe and perform the traction. These legs are designed to allow self-locking. In addition, they were also designed to maintain a constant angle relative to the internal surface of the pipe, within a range of pipeline diameters. For this purpose, it has its own geometry on its contact surface, as shown in FIGS. 4a and 4b.

[0048] According to FIG. 4a, the leg curve was constructed by joining several points through a spline, in order to illustrate the method, as a non-limiting example, the design procedure for a 4 leg on a 4-inch pipe is represented. The points are obtained through straight lines, as shown in FIG. 4a. For each pipeline diameter (from 100.5 to 104 mm), the distance from the center of the fluke axis to the contact point is calculated at a constant angle of 4, which is fixed at 18.50 mm. The value of 18.50 mm represents the distance from the center of the robot to the center of the leg axis. Then, with these values, lines are constructed with an angle between them of 6 (determined through iterations and adjustments). The line ends (dots) are connected through a spline, as shown in FIG. 4a. Further, on every 6 that the leg rotates in relation to its axis, it advances 0.5 mm radially. Thus, as can be seen in FIG. 4b, the angle is kept constant at 4 for the range used (100.5 to 104 mm). Other dimensions and geometries are designed to meet other design requirements.

[0049] Alternatively, the curve can be obtained numerically, for example, through the numerical integration of the equation

[00001]$\frac{\mathrm{dy}}{\mathrm{dx}}=\frac{1+\frac{y}{x}.Math.\tan }{\frac{y}{x}-\tan },$

where x and y are the values on the cartesian axes and is the desired contact angle.

[0050] It is important to highlight that in order to design the leg several other aspects had to be analyzed. As it is a piece that works in association with others, it cannot be considered just its curvature. Correct operation depends on several factors. The example given herein was for the 4 leg, but it is important to note that for each angle (4, 7.5, 10 . . . ), there is a need for a different detailed analysis.

[0051] As shown in FIGS. 2 and 3, some small cylinders (12) perform the opening of the legs. Flexible couplings (13) connect the leg sets to each other, to the tool, to the cylinder, or to other parts of the robot. Connectors (14) allow hydraulic fluid to flow from the manifolds for the cylinders. The main hydraulic cylinder (15) is responsible for the front or rear displacement. Some guides (16) keep the cylinder in its course. Finally, cable protectors (17) preserve the hydraulic hoses.

[0052] FIG. 5 shows a motor pump module in detail and FIG. 6 shows the manifolds module in detail. The flexible body reservoir (21) is responsible for keeping the hydraulic oil separated from the medium and for balancing the reservoir pressure with the medium pressure. The electric motor (22) is responsible for moving the hydraulic pump (23). Additionally, a tensioner (24), possibly in the form of a helical spring, is responsible for keeping the reservoir (21) tensioned. A check valve (25) allows the valves to operate independently, and the structure (26) is responsible for supporting the set. Finally, the manifold with the valves (27) is responsible for directing the hydraulic fluid to one side of the main piston of the cylinder, or to the auxiliary pistons.

[0053] To allow the energy transfer over long distances, an energy electrical transfer is used, from the launch site (platform) to the robot itself. This energy is converted into hydraulic power through motor pump sets (05). The hydraulic fluid then passes through manifolds (06) and actuates the so-called displacement cylinders and the cylinders for opening the legs. The hydraulic circuit used to actuate the cylinder can be a regenerative circuit, which allows a higher forward speed for the cylinder.

[0054] There is the possibility for manifolds to be responsible for controlling the system, or for the engine and pump system be installed either inside or outside a reservoir, without impairing its function, provided that the system remains sealed, with the hydraulic fluid returning into the reservoir.

[0055] To enable the cylinder to operate, the reservoir was designed with a body of elastomeric material (synthetic rubber), as shown in FIG. 7, which has the necessary elasticity to deform as the fluid volume inside the reservoir varies. Also, due to its flexibility, the reservoir allows the equalization between the internal and external pressures. At its ends, hydraulic connections for input and output have been provided, so that it is possible to connect it to actuators through hoses. In FIG. 7 are represented: the reservoir with flexible body (21), the hydraulic pump (23), and the ends with connections for inlet and outlet of the working fluid (28).

[0056] The concept of a reservoir with a flexible body is represented in FIGS. 8a and 8b. Due to the fact that the reservoir has a flexible body, there is an equalization of the internal pressure Pi with the external pressure Pe, so that Pi=Pe. This causes the pressure that reaches the cylinder chamber to be Pe added to the pressure JP that the pump needs to make available for the piston to carry out the movement. FIG. 8a illustrates the forward cylinder and FIG. 8b the backward cylinder. It is represented: motor pump (05), closed/flexible reservoir (21), hydraulic pump (23), advance chamber (29), cylinder (30), recoil chamber (31), cylinder rod (32), variable reservoir volume (33).

[0057] As a consequence of the asymmetric cylinder chambers (with non-passing rod) having different volumes and the entire working fluid remaining in a tight system, the volume of the reservoir must vary so that overpressure does not occur in it. This happens because the recoil chamber has a rod passing through it, which does not occur in the advance chamber. Thus, when the piston recoils, part of the fluid that was previously in the advance chamber (which has a greater useful volume) passes into the volume of the cylinder advance chamber, while the other part (referring to the volume occupied by the rod) passes to the inside of the reservoir, so that there is a greater amount of fluid in its inside. In general, the cylinder piston recoil operation becomes possible due to the flexibility effect of the reservoir body proposed in the invention. The volume variation present in the reservoir is also represented in FIGS. 8a and 8b.

[0058] The reservoir presented in this invention can be used in low and high pressure environments, since there is equalization of the internal pressure with the external one, and in situations where there should be no direct contact between the fluid in the internal work environment and the external environment. By compensating the pressure difference, the developed system can be used in situations where the ambient pressure is high, relative to the working differential pressure. In this case, the motor pump system sums its nominal differential pressure in relation to the pressure of the external local atmosphere, ensuring the proper operation of the actuator in terms of speed and force available.

[0059] FIG. 9 presents a preferential configuration for the hydraulic control circuit of the forward and backward cylinders. This hydraulic circuit uses a regenerative circuit in order to increase the displacement efficiency. Additionally, it has an automatic depressurization system in case of failure and a set of two or more motor pumps for redundancy.

[0060] FIG. 10 shows a preferred configuration for the hydraulic control circuit of the auxiliary cylinders, both for the forward and backward system. The auxiliary cylinders have spring return, and the hydraulic system is automatically depressurized in the event of a power failure or failure. Thus, in the event of a power outage or failure, the legs are automatically retracted.