RU2773700C1 - In-line intelligent pig for gas pipelines - Google Patents

Abstract

FIELD: gas industry.

SUBSTANCE: invention can be used for in-line diagnostic of gas pipelines. The essence of the invention lies in the fact that the in-line intelligent pig for gas pipelines contains a housing with insulation joints and centering wheels, measuring instruments and a speed control system including a braking system, while it is made in the form of three separate sections: battery, measuring instruments and speed control connected by hinges, while in the speed control section there is a bypass channel, the profile of which in the longitudinal section has a streamlined shape, in the narrow part of the bypass channel there is a flap made in the form of a rotary shutter to regulate the cross-sectional area of the bypass channel, and the braking system consists of at least two pairs of wedges located on the periphery at diametrically opposite points of the pig, each pair consists of an inner and an outer wedge, in this case, the inner wedge is rigidly fixed to the pig in the axial direction and installed with the possibility of moving in the transverse direction, the outer wedge has a hinge attachment and is installed with the possibility of moving both in the longitudinal direction and perpendicular to the axis of the pig.

EFFECT: providing the possibility of developing an in-line intelligent pig for low-pressure gas pipelines (up to 10 atm), driven by gas pumped through the pipeline, having a control system to maintain a constant speed of movement during the passage of pipeline sections containing stoppers.

1 cl, 3 dwg

Description

The invention relates to the oil industry, in particular to instruments and apparatus for in-line diagnostics of low-pressure gas pipelines intended for pumping associated petroleum gas, and is aimed at developing the design of an inspection tool that provides continuous removal of diagnostic data when it moves inside the pipeline.

At present, diagnostics of gas pipelines is carried out by in-line pigs driven by the pumped gas. A necessary condition for high-quality diagnostics is the constancy of the speed of the projectiles. If the pipeline does not contain inhomogeneities (stoppers), then the movement of such a projectile occurs at a constant speed. However, in the presence of inhomogeneities, the movement becomes uneven: the lower the pressure in the pipeline, the more uneven the movement of the projectile. It is known from experience that in order to ensure the movement of the projectile at a constant speed, it is necessary that the pressure in the pipeline be at least 30 atm. In pipelines for associated petroleum gas, the pressure usually does not exceed 10 atm. Diagnostics of such pipelines by existing models of in-line diagnostic tools is difficult, and sometimes not possible. Firstly, this is due to the fact that with an uneven movement of the projectile, not all defects in the pipeline can be detected. Secondly, when the projectile accelerates, the forces of its interaction with the pipeline walls increase, which can lead to the destruction of both the projectile and the pipeline.

Known "In-line inspection apparatus and a method of moving it in the main gas pipeline at a given uniform speed" (RF patent No. 2451867, publ. which can operate in three modes: as a motor, brake or passive device.

The disadvantage of this device is the constant mechanical contact of the active (connected to the drive) wheels of the diagnostic projectile with the pipeline body, accompanied by wear of the contact surfaces and the need to equip the projectile with a powerful battery that ensures its movement inside the pipeline.

Known are “In-tube inspection projectile with controlled movement speed” (RF patent No. 2318158, published on February 27, 2008) and “In-tube inspection projectile with adjustable movement speed” (RF patent No. 2369783, published on 10/10/2009), which propose use four peripheral cylindrical bypass channels, closed by valves that are opened by an electric drive, by extending them in the direction of the axis of the channels (the rotational movement of the valve stem is converted into their translational movement). Valves after their opening remain on the axis of the channel.

This solution is not sufficient, since the speed control requires instantaneous operation of the valves when the projectile breaks off the stopper, which cannot ensure the rotational movement of the valve stem. In addition, an unsteady flow is established behind the cylindrical channels and valves, so the forces acting on the projectile will not be stationary. This will make it difficult to stabilize its speed.

The closest to the claimed invention in terms of essential features and the achieved effect is the "Defectoscope-projectile for internal inspection of pipelines" (RF patent No. 2102738, publ. 1998). The flaw detector-projectile is equipped with a bypass branch pipe for bypassing the product transported through the inspected pipeline and an automatic movement speed control system containing a movement speed sensor, a movement speed control unit and a regulator in the form of a brake device interacting with the pipeline wall - a multi-section ring electromagnet. This device is taken as a prototype.

The common features inherent in the prototype and the claimed technical solution are: a body with a system of cuffs and centering wheels, measuring instruments placed in the body and a speed control system containing a braking system.

The main disadvantage of the known device, taken as a prototype, is the high energy consumption of batteries during braking. Indeed, under typical conditions: the mass of the projectile is 600 kg, the acceleration during deceleration is 10 m/s ² , the deceleration time is 1 s, we find that the deceleration force is 6000 N, and the force of pressing the electromagnetic brake to the pipeline wall is N = 20000 N (friction coefficient 0, 3). The displacement of the magnet is about L = 5 cm. The energy consumed by the battery will be about N⋅L = 1000 J. The power is about 1 kW for one braking with one brake. The minimum number of brakes is two. It can be seen that electromagnetic braking requires the use of a high-capacity battery. This further increases the mass and cost of the projectile, and further complicates the speed control.

The objective of the present invention is to develop an in-line diagnostic projectile for low pressure gas pipelines (up to 10 atm.), Driven by gas pumped through the pipeline, having a control system to maintain a constant speed of movement when passing pipeline sections containing stoppers.

The problem was solved due to the fact that the well-known in-line diagnostic projectile for gas pipelines, containing a housing with cuffs and centering wheels, measuring instruments and a speed control system, including a braking system, according to the invention, is made in the form of three separate sections - battery, measuring instruments and movement speed control, interconnected by hinges, while in the movement speed control section there is a bypass channel, the profile of which in the longitudinal section has a streamlined shape, in the narrow part of the bypass channel there is a damper made in the form of a rotary shutter to control the cross-sectional area of the bypass channel, and the braking system consists of at least two pairs of wedges located along the periphery at diametrically opposite points of the projectile, each pair consists of an internal and external wedge, while the internal wedge is rigidly fixed to the projectile in the axial direction and at is mounted with the possibility of movement in the transverse direction, the outer wedge has a hinged fastening and is installed with the possibility of movement both in the longitudinal direction and perpendicular to the axis of the projectile.

Features of the proposed technical solution, different from the prototype: the projectile is made in the form of three separate sections - battery, measuring instruments and speed control, interconnected by hinges; a bypass channel is located in the speed control section; the profile of the bypass channel in the longitudinal section has a streamlined shape; in the narrow part of the bypass channel, a damper is installed, made in the form of a rotary valve to control the cross-sectional area of the bypass channel; the braking system consists of at least two pairs of wedges located along the periphery at diametrically opposite points of the projectile, each pair consists of an internal and external wedge, while the internal wedge is rigidly fixed to the projectile in the axial direction and is mounted with the ability to move in the transverse direction , an external wedge, has a hinged fastening and is installed with the possibility of movement, both in the longitudinal direction and perpendicular to the axis of the projectile.

The division of the diagnostic projectile into sections ensures its geometric cross-country ability. The projectile speed is controlled by opening and closing the central bypass channel, which is blocked by a shutter, which is made in the form of a rotary shutter. The bypass hole profile is made in the form of a streamlined body. Additional regulation of the speed of the projectile, when it accelerates when it breaks off the stopper, is carried out by a system of mechanical brakes.

The essence of the invention is illustrated by the drawings shown in Fig.1-3.

In FIG. 1 shows a general view of the diagnostic projectile, Fig. 2 - section of traffic control, in Fig. 3 - braking system.

The diagnostic projectile (Fig. 1) is made in the form of three separate sections - battery 1, measuring instruments 2 and motion control 3, interconnected by hinges 4. This type of fastening allows sections 1 -3 to rotate relative to each other. The battery section 1 and the instrumentation section 2 are centered in the pipe by passive wheels 5. The control section 3 is centered and sealed by cuffs 6.

The control section 3 (figure 2) consists of a housing 7 with a central bypass channel 8 and a braking system. In longitudinal section, the profile of the bypass channel 8 has a streamlined shape to minimize interaction with the gas flow. In the narrow part of the bypass channel 8, a rotary damper 9 is installed, made in the form of a rotary valve to control the cross-sectional area of the bypass channel 8.

The braking system (figure 3) consists of at least two pairs of wedges located along the periphery at diametrically opposite points of the projectile. Each pair consists of an inner wedge 10 and an outer wedge 11 (or anchor). The inner wedge 10 is rigidly fixed to the projectile in the axial direction and is mounted for movement in the transverse direction.

A rubber pad 13 is installed on the surface of the anchor 11 in contact with the inner wall of the pipe 12. The outer wedge 11 is fixed by a hinge 14 to the lever 15, which in turn is fixed to the body 7. The outer wedge 11 is mounted with the ability to move both in the longitudinal direction and perpendicularly projectile axis.

In FIG. 3 position 16 shows the electric drive, 17 - rod; 18 - the second electric drive; 19-spring.

Diagnostic projectile works as follows.

When pumping gas, a pressure drop is created on the projectile. Pressure forces move the projectile along the pipe. On straight sections of the pipeline, in the absence of irregularities or stoppers on its inner walls, the friction force is constant and is balanced by pressure forces. The projectile moves at a constant speed. In the presence of inhomogeneities, the friction force becomes variable, the pressure force is controlled by slightly opening the damper 9. The damper is opened using the electric drive 16.

If the projectile hits an obstacle and stops, and the gas pumping continues, then the pressure drop across the projectile increases. When the stopper is destroyed under the action of pressure forces, the projectile begins to accelerate, which can lead to the loss of diagnostic information. At this moment, the mechanical brake is activated: the rod 17, using the electric drive 18, presses the inner wedge 10 to the anchor 11, which, through the rubber gasket 13, comes into contact with the wall of the pipeline 12. At the same time, the spring 19 is stretched, which will return the anchor 11 to its previous position, after the removal of the wedge 10. When the anchor 11 comes into contact with the pipeline wall, its speed of movement along the pipeline decreases. The diagnostic projectile, continuing to move at the same speed, presses the inner wedge 10 to the anchor 11. The wedges slide along the contact surface, which increases the pressing of the outer wedge (anchor) to the surface of the pipeline, the projectile stops. Deceleration occurs due to the displacement of the wedges caused by the deceleration of the outer wedge (anchor) against the pipeline wall and the inertia of the projectile.

After stopping, the damper 9 opens in the central bypass channel 8. The pressure at the front and rear ends of the projectile begin to equalize.

The removal of the projectile from the mechanical brake occurs by radial movement of the rod 17 and the formation of a gap between the wedges 10 and 11. In this case, the outer wedge (anchor) 11 is moved away from the wall of the pipeline 12 due to the spring 19 and does not prevent further movement of the projectile.

Thus, the use of the proposed design allows you to control the speed of the projectile inside the oil and gas pipeline.

Claims (1)

In-line diagnostic projectile for gas pipelines, containing a body with cuffs and centering wheels, measuring instruments and a speed control system, including a braking system, characterized in that it is made in the form of three separate sections - battery, measuring instruments and speed control, interconnected hinges, while in the speed control section there is a bypass channel, the profile of which in the longitudinal section has a streamlined shape, in the narrow part of the bypass channel there is a damper made in the form of a rotary valve to control the cross-sectional area of the bypass channel, and the braking system consists of at least two pairs of wedges located along the periphery at diametrically opposite points of the projectile, each pair consists of an internal wedge and an external wedge, while the internal wedge is rigidly fixed to the projectile in the axial direction and is mounted with the ability to move in the transverse direction and, the outer wedge is hinged and mounted for movement both in the longitudinal direction and perpendicular to the axis of the projectile.

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