RU2395750C2 - In-tube fault detection device with controlled movement speed - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: in-tube fault detection device with controlled movement speed, which includes cylindrical housing, consists of two modules with possibility of axial back-and-force movement of one relative to the other, cups, wheel supports, through holes for product along housing, reversible hydraulic drive, control system enclosed in tight controller, odometres, also includes additional tight container, device for changing the pressure drops between front and rear modules. At that, hydraulic drive is equipped with four hydraulic motors equipped with displacement sensors, additional electric drive is introduced; at that, movable rear module of the device is made in the form of front and rear steel walls with holes attached to each other with peripheral hollow cylinder with thickenings in which there inserted are rods, on front side, which have poppet valves, and on rear side - their attachment points to rear wall; on external surface of cylindrical housing of rear module there fixed is polyurethane hollow cylinder with front and rear cups for providing the possibility of back-and-forth movement of rear module relative to cylindrical support inner surface in rear part of front module; at that, additional tight container is connected coaxially to inner cylindrical part of housing, inside it there installed is electric engine of hydraulic pump, electric drive of distributor, tank with fluid and computer control system of hydraulic motors; on four external edges of container there installed are four hydraulic motors the stocks of which are connected to elastic attachment points to rear cover of rear module of the device; at that, on stocks there installed are displacement sensors the outputs of which are connected to the appropriate inputs of control system.

EFFECT: improving control accuracy of speed at simplifying the design of in-tube fault detection device.

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Description

The invention relates to in-pipe shells for inspection of trunk pipelines with increased stability of speed.

Known flaw detector for in-line inspection of pipelines (patent RU No. 2102738, IPC G01N 27/82, G01N 27/87). The projectile is equipped with a bypass pipe for bypassing the product transported through the pipeline being examined and an automatic speed control system containing a speed sensor, a control unit with a speed controller and a regulating body in the form of a brake device interacting with the pipe wall.

The disadvantage of this projectile is that the introduction of an electromagnet for the braking device requires a large expenditure of energy, and the battery power is limited. In addition, speed control only due to friction forces leads to increased wear of the contact surface of the brake device and the walls of the pipeline.

Known scraper for cleaning the inner surface of the pipeline with a variable speed (US patent No. 5208936 from 05/11/1993, MKI B08B 9/04), which consists of a cylindrical body with a first and second open end, an annular seal between the pipeline and the housing, a locking element located inside the housing to block the flow of fluid passing through the housing, but passing through numerous second holes, the first holes include devices that come into contact with the second holes, and which are repusknye channels defining the fluid flow passing values, velocity sensors of the scraper, the drive control means and the closing means. The first and second holes are located around the circumference around the first and second plates, and the bypass channels include numerous tubes passing between the corresponding tubes of the first and second holes and form a central cavity. This device does not allow to stabilize the velocity of the in-tube projectile at the maximum gas bypass due to the plates blocking the gas flow.

A known method of in-line flaw detection and a flaw detector for its implementation (RF patent No. 2109206, F17D 5100, B08B 9/04 of 04/20/1998, authors Efremova GA, Usoshina VA, etc.), which consists in measuring the parameters of the material of the pipe walls and the magnitude of the electrical signals recorded by the flaw detectors in the presence of defects, during the movement of the flaw detector-projectile through the pipeline in the flow of the transported product, determine the coordinates of the detected defects, register them, make a rest from the control system new device and return it to the coordinates of the detected deviation, perform flaw detection at a given speed, process and record the measurement results, flaw detectors are mounted between the poles of the permanent magnets and placed in groups in cassettes that cover the entire cross section of the pipeline, the flaw detector is a two-link mechanism with a hydraulic axial drive reciprocating movement of one link relative to the other, each link has supporting organs.

This technical device is taken as a prototype. The disadvantage of the prototype is the complexity of the design and structural lack of sensors and their connections that impede the implementation of the control system for the speed of the flaw detector-projectile.

The objective of the invention is to improve the accuracy of speed control and simplify the design of the projectile flaw detector.

The task is achieved due to the fact that in an in-tube projectile-flaw detector containing a cylindrical body, consisting of two modules with the possibility of axial reciprocating movement of one relative another, cuffs, wheel bearings, passage holes for the product along the body, reversible hydraulic drive, control system enclosed in a sealed container, odometers, introduced an additional sealed container, a device for changing pressure drops between the front and rear modules, and water provided with four hydraulic motors provided with displacement sensors. An additional electric drive was also introduced, while the movable rear module of the projectile is made in the form of front and rear steel walls with holes interconnected by a peripheral hollow cylinder with bulges, into which rods are inserted, having cone valves on the front side and their attachment points on the back side to the back wall. A polyurethane hollow cylinder with front and rear cuffs is mounted on the outer surface of the cylindrical housing of the rear module to allow axial reciprocating movement of the rear module relative to the cylindrical supporting inner surface at the rear of the front module. In this case, an additional sealed container is connected coaxially with the inner cylindrical part of the housing, inside it there is a hydraulic pump electric motor, a distributor electric drive, a fluid reservoir and a computer control system for hydraulic motors, four hydraulic motors are installed on the four outer faces of the container, the rods of which are connected by elastic connection nodes to the rear rear cover module projectile, while on the rods installed displacement sensors, the outputs of which are connected to the corresponding inputs of the management topics.

The proposed device of the in-tube projectile-flaw detector measures the distribution of the magnetic field induced in the pipeline walls by magnets placed on the projectile using ferromagnetic sensors or Hall sensors, the inner surface of the pipe when the projectile moves through the pipeline in the flow of the transported product. The electrical signals of the sensors are recorded and stored. Using projectile coordinate meters, such as odometers, determine the coordinates of defects and the velocity of the projectile. At the same time, the projectile speed is maintained within predetermined limits by means of a speed control device, increasing or decreasing the cross sections of the through holes.

Figure 1 and figure 2 shows a structural diagram of a bypass in-tube projectile - flaw detector (projectile), figure 3 shows a cross section of the projectile along aa, figure 4 shows a view of the projectile in arrow B. Figure 5 shows the connection diagram hydraulic drive with control system. Figure 6 shows a diagram for calculating valve movements. Figure 7 shows the assembly of the rod to the rear wall.

The projectile includes a cylindrical body 1 with cylindrical passages 2 constituting the front module of the projectile. The rear part of the projectile 3 that is movable relative to the housing 1 and constitutes the rear movable module, consists of a steel frame containing the front 4 and rear 5 walls with openings for passing gases. The front 4 and rear 5 walls are connected by a shell 6 with four longitudinal cylindrical openings with bulges 7, inside of which are inserted rods 8, ending on the front with cone-shaped valves 9, and with the back - fastening devices 10 'to the rear wall 5 in the form, for example, of nuts with stoppers (not shown). To ensure an elastic movable connection of the rear movable module 3 with the housing 1, a support, for example, polyurethane cylinder 11 with a front 12 'and rear cuffs 12 ”is installed on the outer surface of the shell 6. As a guide for the movable rear module 3 of the projectile acts the inner cylindrical surface 13, made in the shell body 1, bounded in front by a shoulder. It is a limiter for the front wall 2 of the module 3 of the projectile. The supporting additional container 14 is connected, for example, by bolts (not shown) to the inner end of the rear side of the cylindrical body 1. On its four faces are hydraulic actuators 15, rods 16, which are connected at their ends by a fastening unit (Fig. 5) to the back cover 5 so in such a way as to ensure the possibility of transmission of force from the hydraulic actuators in both positive and negative directions along the longitudinal axis of the projectile. Inlet and outlet pipelines to the hydraulic motors and their switching device, a hydraulic pump and a hydraulic pump drive electric motor, an additional distribution electric drive are installed in the inner sealed part 17 of the additional container 14. In the internal part 17 of the additional container 14, the electronics and power supply units are also installed.

The inner cavity of the cylindrical body 1 is sealed with a lid 18, forming a sealed (main) container. It contains orientation and navigation devices 19, an electronics unit 20 for collecting and storing information, a power supply 21 in the form of, for example, lithium batteries. On the peripheral part of the cylindrical body 1 are either sensors for detecting corrosion and other defects of the pipe 22, or sensors for determining the profile of the pipe 22, etc. The projectile is also equipped with cuffs 23 with wheels, wheel odometers 24.

The hydraulic drive consists of hydraulic motors 25, 26, 27, 28, a fluid reservoir 29, a hydraulic pump 30 driven by an electric motor 31. Hydraulic motors 25 ... 28 are connected by pipelines 32 and 33 to the left and right outputs of the fluid distributor 34, which is connected to an additional electric drive 35 dispensers. The pipe 36 is connected to the actuator 35.

In turn, the liquid distributor 34 is connected through the electric actuator 35 of the distributor to the discharge outlet 37 of the hydraulic pump 30, its suction inlet 38 is connected by a pipe 39 to the tank 29. The inlet 40 of the safety valve 41 is connected to the pipeline 36, and its outlet is connected via a pipe 42 to cistern 29.

All hydraulic connections and elements are sealed, there are hermetic couplings of the inlet and outlet pipelines from the container 14. A displacement sensor 43 is installed on the rod 16 of the hydraulic motor 25, its electrical output is connected to the corresponding input 44 of the computer control system 45. The output of the odometer 24 is connected to it 46 The pipe 47 connects the pipe 32 to the discharge cavities of the hydraulic pumps 26, 27, 28.

The output 48 of the control system 45 is connected to the input of the electric actuator 35 of the distributor, and the output 49 of the control system 45 is connected to the input of the electric motor 31.

The fastening assembly of FIG. 5 consists of washers 50, a rubber or polyurethane sleeve 51, a nut 53 and a cotter pin 54. Thanks to this fastening, an elastic connection of the hydraulic actuator rods 16 to the rear cover 5 is ensured, which ensures uniform distribution of forces across the four hydraulic pumps. It should be noted that the cover 5 also has elasticity, which contributes to the coordination of the connections of all the rods of the four hydraulic actuators with the rear cover 5, caused by the inaccuracy of their manufacture. In the manufacture of the projectile, the rigidity of the attachment points of the back cover can be further reduced by cutting the jumpers between the mounts of the nodes 10 'on the back cover 5.

The shell works as follows. When it is stocked in the pipeline, the control system 44, in the absence of projectile movement (V = 0), installs, using the rods 16 of the hydraulic pumps 25, 26, 27, 28, the movable rear module 3 to the leftmost position, which is shown in Fig. 1 When applying gas pressure P (FIG. 1), the projectile begins to move, since the valves 8 completely overlap the four through holes 2. At a high velocity V of the projectile’s movement (for example, more than 4 m / s), the control system 44 from output 49 includes an electric motor 31 from the odometer and it through the coupling 55 actuates the hyd the pump 30. In addition, according to the signals of the control system from the output 48, the electric drive 35 installs the fluid flow distributor 34 so that the fluid received through the pipe 32 (or through the pipe 33) moves the rod 16 to a position in which the rear movable module 3 is displaced a fixed position in which gaps are formed between the valves 8 and the through holes 2. In this case, the pressure difference between the front and rear walls will decrease, and the velocity of the projectile will decrease. To ensure stability and quality of speed regulation V, a displacement sensor 43 of the rod 16 is introduced into the hydraulic motor 44. The back of the projectile is protected by a casing with holes 56, from the front by a casing 57 with a ring 58.

The process of overlapping or opening the area of bore cylindrical sections is carried out by moving the rear module of the projectile relative to the front, based on the established dependence of the velocity of the projectile, determined by the odometer, on the size of the area of opening of the bore holes

where the movement of the rear module relative to the front module causes the opening of the passage area in accordance with the formula

where R ₀ is the radius of each bore;

L ₀ is the length of the locking cone;

n is the number of through holes;

y - movement of the rear module relative to the front.

The control law of the hydraulic drive is set based on the ratio

where K _OS - gear ratio of the feedback circuit;

P _n - pressure at the outlet of the hydraulic pump;

S _n is the piston area of one hydraulic motor;

F is the force developed by four hydraulic motors.

The driving force of the projectile F _dv is determined by the approximate formula

where ΔF is the force of motion, determined by the difference ΔP of static gas pressures on the front and rear sides of the projectile, varying depending on the degree of overlap of the cylindrical passages 2;

ρ is the gas density;

W is the gas velocity relative to the projectile,

S ₁ and S ₂ - the cross-sectional area of the rear movable part 3 of the projectile and its stationary (relative to the housing 1) part;

ξ ₁ , ξ ₂ - resistance coefficients of these parts of the projectile;

m _c is the mass of the projectile;

g is the acceleration of gravity;

θ is the pitch angle of the projectile;

F _mp is the friction force.

We have to determine the speed W

Because gas velocity relative to the projectile is determined by the formula

where υ is the gas velocity relative to the pipe, the velocity of the projectile relative to the pipe F is

It is easy to see that increasing the opening of passages with the help of valves 9 reduces the velocity of the projectile. The calculations showed that if the through-holes in the shell of the projectile are fully open, then the drag force of the projectile is less than the force of friction of the projectile on the inner wall of the pipeline. In this case, the projectile does not move. When approaching the rear to the shell of the projectile, the openings in the housing partially overlap, the drag force increases, and the projectile begins to move along the pipeline.

The hydraulic resistance coefficients ξ ₁ and ξ ₂ included in formulas (1) - (5) are expressed in terms of the open cross-sectional area of the passage S ₃ , the entire cross-section of the passage S ₄ and the pipe section S _o according to the formulas [Reference for hydraulic resistance. // I.E. Idelchik: M .: Mechanical Engineering, 1975. - C.125]

where R is the radius of the cross section of the pipeline;

r ₁ and r ₂ are the radii of the lower and upper boundaries of the cylindrical passages;

C _x1 = 0.15, C _x2 = 0.2, τ = 0.2 - coefficients that take into account the shape of the head of the projectile.

The second term in formula (7) takes into account the mutual influence of the rear movable module 3 and the shell body 1 on each other.

If ΔP _{2 is} the difference in gas pressure between the front and rear ends of the shell, then ΔP ₂ is determined by the formula

where ξ is the averaged resistance coefficient.

As the calculations show, the ΔР value changes little with a change in the area of the open part of the cross-section of passages and the velocity of the projectile in the pipeline at constant working pressure and working speed of gas in the pipeline. Figure 6 shows the position of the valve 8, closing the cylindrical passage 2 of circular cross section R ₀ (dashed line), as well as its position, shifted to the right by y. 6, the radius R corresponds to the area of overlap of the passage through the valve, therefore, the open area for n passes is

An increase in S leads to a decrease in F _dv (formulas 1 and 2) and, consequently, the velocity V of the projectile relative to the pipeline.

If we approximate the experimentally measured dependence of the projectile

;Where

;

k is the coefficient of proportionality,

then it will be possible to analytically describe the pressure control law P _n supplied to the hydraulic motors from the hydraulic pump

where K _OS - the gear ratio of the sensor 43;

To _F is the gear ratio of the hydraulic drive.

Calculations show that the force with open passages 2 acting from the side of the moving gas on the tail of the projectile is 10-15% of the total gas-dynamic force acting on the entire projectile. When closing the aisles, the distribution of forces is proportional to the areas S ₀ and S.

The application of the present invention will significantly simplify the method of controlling the speed and design of the in-tube shell-flaw detector.

Claims (1)

 An in-line variable velocity flaw detector containing a cylindrical body, consisting of two modules with the possibility of axial reciprocating movement of one relative other, cuffs, wheel bearings, passage holes for the product along the body, reversible hydraulic drive, control system enclosed in a sealed container , odometers, characterized in that an additional pressurized container is additionally introduced into the composition of the flaw detector, a device for changing differences yes between the front and rear modules, while the hydraulic drive is equipped with four hydraulic motors equipped with displacement sensors, an additional electric drive is introduced, while the movable rear projectile module is made in the form of front and rear steel walls with holes interconnected by a peripheral hollow cylinder with thickenings into which rods are inserted that have cone valves on the front side and their attachment points to the rear wall on the back side; a liurethane hollow cylinder with front and rear cuffs to enable axial reciprocating movement of the rear module relative to the cylindrical supporting inner surface in the rear of the front module, while the additional sealed container is connected coaxially with the inner cylindrical part of the housing, a hydraulic pump motor, an electric drive of the distributor are installed inside it , a tank with liquid and a computer control system for hydraulic motors, on the four outer faces of the contour Four hydraulic motors were installed, the rods of which are connected by elastic knots to the rear cover of the rear projectile module, while the rods are equipped with displacement sensors, the outputs of which are connected to the corresponding inputs of the control system.

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