RU2363554C2 - Method for cleaning of pipeline and device for its realisation - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention is related to pipeline transport and may be used for pipeline cleaning. In method that includes displacement of pipe-cleaning mechanism along pipeline with collars, on periphery of which liquid jets are generated, which remove deposits from pipe wall by pressure of collar elastic petals, generation of jets along the whole surface of collar and removal of deposits by pulsating liquid flow, in liquid flow zone is created for generation of cavitation nuclei, besides, jets are generated with different speeds, and they are formed by pipeline wall and upper elastic petals, from cleaned section of pipeline deposit particles are removed, which are introduced into generated jets by liquid flow, and during device motion along pipeline petals contact with wall of cleaned pipeline by bent ends and create segment slots with it. Device for method realisation comprises resilient and elastic petals installed in staggered order on hubs connected to each other, in which petal ends are bent relative to longitudinal axis of device and create segment slots during contact with cleaned pipeline wall. Petal ends fixed in hubs are arranged in the form of trapezoid, moreover, semi-openings are arranged on lower petals on trapezoid sides, and openings are provided on upper petals.

EFFECT: provides for cleaning of deposits, hardness of which exceeds 2 units according to Mohs scale.

2 cl, 8 dwg

Description

The invention relates to pipeline transport and can be used to clean the inner surface of pipelines from deposits. A known method of cleaning pipelines from deposits, which consists in the fact that a pipe-cleaning device is moved through a pipe by a fluid pressure, while the liquid is passed through a cleaning device in the form of jets that remove deposits from the pipe’s inner surface, for example, international application WO 86/02293, B08B 9 / 04, С23F 11/00 from 04.24.1986

The disadvantage of this method is that it inefficiently cleans ash disposal pipelines. The closest prototype is a cleaning method in which a pipe-cleaning mechanism with cuffs is moved by a fluid stream along the periphery of which liquid jets are formed to remove deposits from the pipe wall, RF patent RU 2184902 7 F16L 58/04 dated 08/31/2000.

Known devices for implementing this method, for example A.S. USSR V8 9/04 995910, 1983, A.S. USSR V8 9/04 No. 1744844.1988, A.S. USSR В08В 9/04 No. 1688503, 1989.

The disadvantage of these devices is that they do not very effectively clean pipelines of very hard deposits, such as ash removal pipelines.

The closest analogue of the claimed method is a method of cleaning the pipeline, comprising moving through the pipeline a pipe cleaning mechanism with cuffs, on the periphery of which liquid jets are formed, removing deposits from the pipe wall, in which deposits are removed from the pipe wall by pressure of the elastic cuff petals on the deposits, while the jets form the entire surface of the cuff and deposits are removed by a pulsating fluid flow, and in the fluid flow the formation zone of cavitation nuclei is formed (see AS USSR No. 1639800, (tog the same applicant) 1991). In addition, in the known method, as in the claimed one, the liquid jets have different flow rates, because, as follows from the description of the claimed invention (see p. 10), "making elastic petals in the form of plates ... allows you to form jets with different speeds" .

A known cleaning method, according to which compressed gas (air) is supplied in pulses to a liquid stream, is known from RF patent No. 2206415, 2003.

The formation of cavitation nuclei between elastic petals by introducing jets of a stream of liquid, gas (air) and solid particles is also known from RF patent No. 2206415.

The closest prototype is the device according to patent RU No. 2184902, 7 F16L 58/04 from 08/31/2000, an analogue to it is a device for cleaning the pipeline according to the above.with. USSR No. 1639800, containing, as claimed, a shaft with a hub on which elastic and resilient petals are staggered, made with the possibility of contacting with the inner surface of the pipeline.

The disadvantages of the method and device is that they do not allow pipelines to be cleaned of deposits whose hardness exceeds 2 units on the Mohs scale.

The reason for this is that these method and device form a small number of "aggressive bubbles" of cavitation, approximately one bubble of 300,000 cavitation bubbles.

In order to increase the number of “aggressive bubbles”, the following condition must be fulfilled:

- at the time of collapse of the bubbles, they should be in the pores or cracks of the deposits.

This device is also more effective and device No. 1639800, because it can clean pipelines, the hardness of the deposits of which exceeds more than 3 units on the Mohs scale.

Despite the fact that all of the prototypes and analogues used are known, they cannot clean the pipeline from deposits whose hardness exceeds 2 units on the Mohs scale.

In all known devices implementing this method, including in the device by A. with. No. 1639800, the petals are curved in radius.

This is done so that the wedge-shaped petals enter a hole that is free of deposits.

For this reason, the gap between the petals and sediments is always minimal. This achieves the highest rate of water flow through the treatment device. Therefore, deposits are mainly removed due to the hydrodynamic effect of water jets on the deposits, as well as due to the mechanical pressure of the petals on the deposits.

With a hardness of deposits not exceeding 2 units on the Mohs scale, these devices perfectly clean the pipelines from deposits.

With a greater hardness of the deposits, they can no longer be destroyed by the acting forces on the deposits.

Since the device is pressed into deposits, and water stops flowing through the slots formed by the petals.

In this case, deposits are spread by petals and pressed against the pipe wall.

In this case, the petals are deprived of the possibility of their oscillation relative to deposits and hubs.

The second significant drawback of the known devices, including devices for AS No. 1639800, is that the free end of the petal is made narrowing or radial.

This is done in order to reduce the free section of the gap, and therefore, increase the speed of the jet of water flowing from the gap.

Increased jet velocity increases destructive jet deposition.

But the small cross-section of the slots does not allow you to adjust the flow rate of water flowing through the device in a wide range, which reduces the magnitude of the force of the pulses of water and gas acting on the deposits.

The technical result of the invention is the cleaning of pipelines whose hardness exceeds 2 units on the Mohs scale.

This result is achieved by the fact that in the method of cleaning the pipeline, including moving through the pipeline of the chimney mechanism with cuffs, on the periphery of which liquid jets are formed, removing deposits from the pipe wall, in which deposits are removed from the pipe wall by pressure of the elastic cuff petals on the deposits, and the jets form over the entire surface of the cuff with different speeds and jets form the wall of the pipeline and the upper elastic lobes, deposits are removed by a pulsating fluid flow, and in which liquid form nucleation cavitation zone, and a duct portion is removed purified sediment particles introduced into the liquid flow stream generated during movement of the device along the pitch line contact with the wall of the pipeline being cleaned bent ends and form with it segmental gap.

This result is achieved by the fact that in the device for cleaning the pipeline made of hubs interconnected and stitched on them in a checkerboard pattern of elastic and elastic petals, the ends of the petals are bent from the longitudinal axis of the device and form segment gaps upon contact with the wall of the pipe being cleaned and fixed on the hubs with ends made in the form of a trapezoid, moreover, half-holes are made on the lower petals on the sides of the trapezoid, and holes are made on the upper petals.

The movement through the pipeline of a chimney mechanism with cuffs, on the periphery of which liquid jets are formed, removing deposits from the pipe wall, in which deposits are removed from the pipe wall by the pressure of the elastic cuff petals and deposits, while the jets are formed over the entire surface of the cuff and deposits are removed by a pulsating fluid flow, moreover, a formation zone of cavitation nuclei is formed in the fluid flow, while the jets are formed at different speeds and the jets are formed by the pipe wall and the upper elastic petals, etc. This purified with duct portion is removed Fat particles which fluid flow is introduced into the jet formed, while during the movement device of the pitch line contact with the wall of the pipeline cleansed bent portions of petals improves the cleaning rate of the pipeline.

The device is made of hubs interconnected, while elastic and elastic petals are staggered on the hubs. In this case, elastic petals form segment and rectangular slots on the periphery, segment slots are formed by the pipe wall and upper elastic petals, and rectangular slots are formed by the pipe wall and upper and lower elastic petals, and the ends of the petals with which they are fixed on the hubs are made narrower (in in the form of a trapezoid), and on the lower petals are made on the sides of the narrowing of the half-hole, and holes are made on the upper petals to increase the number of “aggressive bubbles” of the cavi tatsii, due to which the speed of cleaning the pipeline increases.

The execution of the free ends of the petals bent to the longitudinal axis of the device allows to increase the magnitude of the pulses of movement of water and gas through the pipeline, which allows to increase the speed of cleaning the pipeline.

The drawings show:

figure 1 - device for cleaning;

figure 2 - the formation of cracks with elastic petals;

figure 3 is a cleaning scheme;

figure 4 - elastic petal with a bent end;

figure 5 - device for cleaning with a ball and a gas supply system;

figure 6 - implementation of the end of the upper plate;

Fig.7 - the implementation of the end of the lower plate;

Fig.8 is a multilayer plate.

The device shown in figures 1, 2, is made of a shaft 1 with hubs, 2, 3, on which elastic petals 4, 5 and elastic petals 6 are staggered.

The elastic petals 4, 5 are made in the form of plates, which contact the wall 7 of the pipeline with ribs 8 and form segment slots 9 with it.

The upper petals 4 form with the lower petals 5 and the wall 7 of the pipeline slots 10. The cross section of the slots 9 is less than the slots 10.

The cleaning circuit depicted in figure 3.

In the pipeline 11 with deposits 12, a treatment device 13 is installed.

Figure 4 shows the elastic petal 4, 5 with bent ends 14.

The device shown in Fig. 5 is made of a pipe-cleaning mechanism 15 and a ball (16 balls) installed in a pipe 17 in communication with a gas supply system 18 and a pump 19.

Figure 6 shows the elastic upper petal 4. The end of this petal 4 is made triangular or trapezoidal. A hole (s) 20 are made on its longitudinal axis.

On the elastic lower lobe 5 (Fig.7) on the sides of the triangle or trapezoid is made half-hole 21 (hole).

The petals 4, 5 can be multilayer (Fig. 8), for example, of the same plates 22, 1 mm thick.

The device shown in figures 1, 2, 3, 4, 6, 7, 8, works as follows.

The device is installed in the pipeline and serves water. By the pressure of the water, the device begins to move through the pipeline. Part of the water in the form of jets passes through slots 9, 10 and erodes deposits with hydrodynamic pressure. The hydrodynamic pressure rinses off the softer part of the deposits, the hardness of which does not exceed 2 units on the Mohs scale.

System 18 in the pipeline 11 or 17 serves portions of compressed gas (air).

Water and air begin to accelerate, dispersing the balls 16, which periodically hit the treatment device 13 and the wall of the pipe 11.

Water moves between the pipe 11 and the ends 14 of the petals 4, 5.

The flow rate of water and gas is accelerated. Since the pressure in the flow of water and gas is constantly changing, the petals 4, 5 oscillate.

The unbroken stream, passing along the bent end 14, hits deposits 12. The pressure of water and gas in the gap formed by deposits 12 and petals 4, 5 increases.

Due to the increase in pressure, the petals 4, 5 bend in the direction opposite to the cleaning course.

The flow pressure on both sides of the petals 4, 5 periodically changes. Due to this, the petals 4, 5 oscillate.

Periodic oscillation of the petals 4, 5 forms the following physical effect.

The fact is that the elastic petals are in contact with the pipe wall only with ribs. Therefore, the specific pressure of the petals on the deposits increases tenfold. A gap forms in the form of a segment between the upper lobe and the wall of the pipeline. Since the elastic petals fluctuate due to pulsations of the fluid flow, these vibrations are transmitted to deposits and the wall of the pipeline. Since the coefficients of linear expansion of the deposits and the walls of the pipeline are not the same, the oscillation frequency of the deposits and the walls of the pipeline are also not the same, and they have different oscillation amplitudes. There are cases that deposits and the wall of the pipe oscillate in antiphase.

All this leads to the formation of microcracks in the deposits, between the deposits and the wall of the pipeline.

These gaps increase all the time and join into larger gaps. Subsequently, the gaps are filled with gas and liquid. When the flow pulsates, liquid and gas are compressed in the gaps. During a decrease in pressure in the flow, forces appear in the cracks that tear deposits off the pipe wall.

In this case, between the petals 4, 5 and deposits 12 there is always a gap that constantly changes its cross section. Through this gap, a stream constantly flows, carrying away the destroyed deposits from the destruction zone.

In the zone of destruction of sediments, the gap between the petals 4, 5 and sediments constantly changes the cross section.

Since the substance is supplied to the deposits in the liquid phase and cavitation bubbles are created in the substance in the zone of destruction of the deposits, while cavitation bubbles in the substance are created by creating a periodically changing pressure having constant and variable components, and these components are selected from the following ratios:

P ₁ = FROM 0.3 to 0.7 (P ₂ + P ₃ );

P ₂ + P ₃ -P1 = 1 to 10G;

where P ₁ is the constant component of pressure (MPa);

P ₂ - variable pressure component (MPa);

P ₃ - saturated vapor pressure of the processed substance at the temperature of its supply to the treatment zone (MPa);

G - tensile strength of the processed substance at a temperature of its supply to the treatment zone (MPa).

Subject to the indicated conditions of simultaneous action of alternating and static pressures on a substance in a liquid phase, cavitation bubbles form in a liquid at the moment when the sum of two values: the amplitudes of the alternating pressure and the pressure of saturated vapor of a substance at a given temperature exceeds the sum of two values: static pressure and liquid strength breaking at a given temperature. This moment in time coincides with the moment of action of the negative half-wave of variable pressure.

During the action of a positive alternating pressure half-wave on a liquid, cavitation bubbles are affected by the sum of two pressures of the amplitude of the alternating pressure and static pressure, which tends to compress the bubbles, i.e. slam them. At the moment of collapse of the bubbles, their walls under the influence of the pressure difference acting on the cavitation bubbles accelerate, acquire kinetic energy and collide in the center. The magnitude of the kinetic energy acquired is sufficient to break the bond between the molecules, as well as between the nucleons, to overcome the repulsive forces of the nuclei and to carry out the interaction between the elementary particles contained in the nuclei of the processed substance. As a result, in the local area of matter at the moment of the disappearance of the cavitation bubble (its collapse), a nuclear reaction occurs with the release of a large amount of energy, which is sent in the form of a shock wave to deposits and destroy them.

The effect of shock waves in a liquid on cavitation bubbles makes it possible to increase the energy release by an order of magnitude, therefore, the destructive force acting on deposits also increases.

If necessary, changes in energy release change the alternating pressure and / or static pressure by changing the power of the portion of the compressed gas, and that the flow pulses are created by increasing or decreasing the flow or discharge of the flowing product into and out of the pipeline.

The pulsating flow makes it possible to increase the rate of collapse of cavitation bubbles. This leads to the fact that even large bubbles have time to collapse in the desired half-life. In addition, it contributes to the formation of cavitation bubbles due to an increase in static pressure and its sharp decrease.

Oscillations of elastic petals increase the rate of formation of microcracks in sediments.

The formation of jets of fluid flow on the inner surface of the pipe flowing from slots with different speeds promotes the formation of vortex motion of the jets. Also for this reason, compressive and tensile forces appear in the deposits, contributing to the formation of cracks in the deposits.

The location of the jets having a greater and lower outflow velocity on the surface of the deposits increases the forces compressing and tearing the deposits.

The division of the fluid flow along the length of the pipeline into three or four zones, in which the pressure range of the flow is different, helps to create a pulsed change in the flow pressure, the creation of local water hammer. This also leads to oscillation of the pipe and sediments with different parameters, which contributes to a more effective destruction of sediments, while the fluid flow is saturated with a large number of smaller particles of sediments.

The contact of elastic petals with deposits only by ribs increases the specific pressure on deposits by tens of times, which leads to effective destruction of deposits, while stripes with incompletely removed deposits form on the wall of the pipeline. In the future, this leads to grinding of these deposits and mixing with the flow of liquid. After the destruction of these strips of deposits, liquid passages are formed through which the fluid flow penetrates into the gaps between the pipe wall and the deposits.

The device depicted in figure 5, operates as follows.

The system 18 in the flow of water supplied by the pump 19 into the pipeline, periodically serves compressed air. The flow of water is saturated with air, its continuity is lost. Therefore, when the flow moves, cavitation develops faster. Air speeds up the speed of the stream and enhances its momentum. The movement of the balls 16 behind the pipe-cleaning mechanism 15 increases the strength of the water hammer and transfers their energy when they hit the pipe-cleaning mechanism 15. When the balls 16 are moved through the pipeline, they hit each other and the wall of the pipe 17, which begins to vibrate. Vibration of the tube contributes to the development of cavitation. When the balls 16 hit the chimney mechanism 15, a blow occurs. This shock serves to determine the location of the pipe cleaning mechanism 15 in the pipe 17.

Example.

We cleaned the F530 mm pipeline through which the ash of the CHPP was transported.

The thickness of the deposits was 80 mm. The hardness of the deposits was 3 units on the Mohs scale. The length of the pipeline is 13 km.

The method was carried out by the device depicted in figure 5.

A pipe-cleaning mechanism 15 with a diameter of 550 mm was installed in the pipeline. The elastic petals 4, 5 were made of steel 65G. Their thickness was 3 mm. Width is 45 mm, length is 250 mm. The diameter of the hub is 180 mm.

Three metal balls with a diameter of 490 mm were installed behind the chimney mechanism.

Water was pumped into pipeline 17 at a pressure of 0.9 MPa, and periodically every 5 minutes, compressed air was supplied at a pressure of 1.2 MPa in an amount of 0.75 m ³ .

The end of the pipeline was opened. After 280 minutes, the pipe-cleaning mechanism 15 and balls 16 came out of the pipeline.

By adjusting the portions of water and air in the pipeline by the gas supply system 18 and the pump 19, as well as the frequency of their supply, the specified values of static and dynamic pressures are obtained.

It also contributes to the collapse of bubbles on the surface of deposits or in their microcracks.

This leads to the fact that most cavitation bubbles become “aggressive”.

It also leads to volley collapse of the bubbles.

Such a technical solution made it possible to clean the pipelines of deposits whose hardness exceeds two units on the Mohs scale.

Check cuts in the pipeline showed that the pipeline is cleaned well.

Using the invention allows to clean pipelines with a hardness of sediments of up to 5 units on the Mohs scale, for example, sludge pipelines, ash removal pipelines.

Claims (2)

1. A method of cleaning a pipeline, including moving along a pipeline of a pipe-cleaning mechanism with cuffs, on the periphery of which liquid jets are formed, removing deposits from the pipe wall, in which deposits are removed from the pipe wall by pressure of the elastic cuff petals on the deposits, while jets are formed over the entire surface of the cuff and deposits are removed by a pulsating fluid flow, wherein a cavitation nucleation zone is formed in the fluid flow, while the jets are formed at different speeds and the jets form a pipe wall oprovoda and upper elastic petals, with a purified portion of the duct removed sediment particles, which fluid flow is introduced into shaped jet, characterized in that during the movement through the pipeline device pitch in contact with the wall being cleaned pipeline bent ends of the petals and form with it segmental gap. 2. A device for cleaning the pipeline, comprising made of hubs interconnected and stitched on them in a checkerboard pattern of elastic and elastic petals, in which the ends of the petals are bent from the longitudinal axis of the device and form segment slots and are attached to the wall of the pipeline being cleaned and fixed to the hubs with ends made in the form of a trapezoid, half-holes are made on the lower petals on the sides of the trapezoid, and holes are made on the upper petals.

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