JP2816968B2 - Passage detection method for spherical pigs - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing solidification or deterioration of quality of a fluid by discharging a fluid in a pipe, or a method for discharging a fluid and then supplying a different kind of fluid after the fluid is discharged. The present invention relates to a method of detecting the movement and passage of a spherical pig having a built-in magnet from the surface of a pipe.

[0002]

2. Description of the Related Art Conventionally, for example, when paying out residual oil in a pipeline and collecting it in a tank, or when sending two or more types of fluids in a single pipeline and collecting them in separate tanks, The pig is put in a pipeline, compressed air or the like is supplied from the rear thereof and moved forward to discharge the fluid.

At that time, if the current position and passage of the pig can be sensed and a signal can be taken out by any method, the valve can be opened and closed, the direction of the pig can be changed, and the pig can be reciprocated. Signals enable automation and unmanned operation, thereby lowering transportation costs and improving transportation efficiency. Therefore, it is very important in operation how to reliably catch the passage of the pig, and if the detection of this passage is hindered, the device itself becomes unusable.

In order to detect the passage of the pig,
Jitsuhei 6-23, which the applicant of the present invention has previously proposed and gained popularity.
No. 829 publication. This is a contact type in which a detection claw is protruded into a pipe, and a pig running in the pipe pushes up the detection claw and senses passage by interlocking a microswitch operated by the pushing force.

[0005] In the case of this contact type sensing, if the pig speed is high, an operation error that the detection claw cannot be pushed up may occur, and if the fluid is easily solidified, the detection claw may be attached to the mounting portion of the detection claw. In some cases, the fluid could enter and solidify, rendering it inoperable. In addition, this contact method has a structure in which the detection claw returns to its original position by the spring force of the spring as soon as the pig passes, but if the rotating shaft on which the detection claw is attached has a small diameter, the force of the spring is reduced. Was unable to return because of the loss.

[0006] For these reasons, recently, FIG.
As shown in FIG. 3B, a permanent magnet 21 is built in a bullet-shaped or gourd-shaped pig 20, and a sensor 22 for detecting a line of magnetic force emitted from the permanent magnet 21 is provided on an outer surface of a pipe line 23 to perform non-contact sensing. The method has been done. In the non-contact sensing method, since the sensor 22 does not directly contact the fluid or the pig 20, the above-described trouble does not occur at all, and the sensor 22 has a semi-permanent life and can be used for a long time. Further, since the pig did not push the protruding claw, the movement of the pig itself was smooth, and the pig could travel in the pipe.

[0007] When the above-described pig 20 having a long or cannonball shape or a gourd-shaped pig 20 is used, the direction in which the lines of magnetic force are emitted does not change even if the pig 20 is rotated in the circumferential direction of the pipe line 23 when traveling. Even if the demagnetizing portion of the magnetic field lines passes when moving below the sensor 22, there is no problem because the magnetic field lines before and after the magnetic field lines can be sensed.

[0008] As another shape of the pig, there is a shape in which a permanent magnet 31 is incorporated in a spherical pig 30 shown in FIG. 10 and sensing is performed in the same manner as in FIG. 9. Since the area of the permanent magnet 31 is small and the distance to the outer peripheral surface is too large if only the magnets are incorporated, it is difficult to generate magnetic lines of magnetic force enough to cover the spherical surface, and the sensor 33 provided on the outer surface of the pipe passage 32 is not provided. It was hard to reach and could not be detected. Therefore, two permanent magnets 41, 41 are provided opposite to each other near the inner peripheral surface as shown in FIG.
By providing an interval at which the magnetic field lines can reach the poles, a magnetic field line flows between the two poles, and a sensing method using a pig 40 that can largely cover the spherical surface has been considered.

[0009]

However, as shown in FIG. 7, the permanent magnets 41, 41 built in the pig 40 do not have the lines of magnetic force uniformly emitted from all positions, and the center of the magnetic poles Lines of magnetic force concentrate on the portion, and the portion has a strong magnetic force, but the middle portion has a demagnetizing portion D with a weak magnetic force.
And since this pig 40 is spherical, the piping 42
When the vehicle travels forward, rotation in the forward direction is applied to change the direction of the line of magnetic force, and depending on the rotation, as shown in FIG.
There is a problem that if the demagnetizing portion D happens to pass immediately below the magnetic sensor 43 attached to the outer surface of No. 2, it cannot be detected.

SUMMARY OF THE INVENTION The present invention has been developed to solve the above problems, and can reliably capture magnetism from a spherical pig moving in a pipe and reliably detect the position and passage of the pig. It is an object of the present invention to provide a method for detecting the passage of a spherical pig, which can automate and unmanned the reciprocating movement, firing and collection of the spherical pig.

[0011]

As a means for solving the above-mentioned problems and achieving the object, the present invention provides a method in which fluid is introduced into a pipe having a start portion and a recovery portion which are inclined obliquely downward at both ends. Is a pig construction method that introduces a spherical pig that moves by pushing from behind, and discharges the fluid by the movement of the spherical pig, wherein the pig has two built-in permanent magnets at a predetermined interval, A magnetic sensor provided at a predetermined position on a pipe line is provided with a magnetic field line flowing from the N pole to the S pole of the permanent magnet during the movement of the spherical pig, and at least one magnetic field attached to the pipe line shifted from the magnetic sensor. A method for detecting the passage of a spherical pig, which is characterized by sensing with a sensor, was developed and adopted.

According to the present invention, in the method for detecting the passage of a spherical pig having the above-described configuration, a permanent magnet having a disk-shaped two-sided two poles is provided near an outer peripheral surface at a predetermined distance from the center of the spherical pig. We developed and adopted a method of detecting the passage of a spherical pig using a spherical pig built in vertically.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in accordance with an example of a one-line system in which different kinds of fluids are sent through one pipe line and collected in separate tanks as shown in the attached drawings 1 and 2. explain. Reference numeral 1 denotes a pipe line for transferring different kinds of fluids. Both ends thereof are a pig launching portion 1b and a pig collecting portion 1c, each of which has a pipe having a diameter larger than the diameter of the pig and is inclined obliquely downward, The pipes 1d and 1e are maintained.

A spherical pig 2 having an outer diameter slightly larger than the inner diameter of the pipe 1 and formed of an elastic body made of rubber or synthetic resin is introduced into the pipe 1, and is provided behind the spherical pig 2. The gas is pushed and moved along the inside of the pipe line 1 by the compressed gas introduced from the tank, and the fluid is discharged. This spherical pig 2
The permanent magnets 3 and 3 are vertically installed at positions close to the outer peripheral surface at a predetermined interval left and right from the center and in the vertical direction. Although the permanent magnets 3 and 3 may be bar magnets, the upper surface as shown in FIG.
It is more preferable to use a disc-shaped magnet composed of two poles, upper and lower, having a pole 3a and an S pole 3b on the lower surface, since the magnetic field lines are large and many come out to cover the spherical surface.

In the movement process of the spherical pig, magnetic lines of force coming out of the built-in permanent magnets 3 are detected by a magnetic sensor 4 provided on the outer surface of the pipe 1 at a predetermined position. The magnetic sensor 4 includes an outer peripheral surface of the pipe line 1 near the starting portion 1b,
A ring 5 fitted on the outer peripheral surface of the pipe line 1 near the collecting part 1c
Attached to a bracket 6 fixed to the bracket 6. That is, as shown in FIG. 3, the left and right magnetic sensors 4 a attached to the bracket 6 a of the central ring 5 a are fitted at the top position at intervals from the central ring 5 a in the longitudinal direction. Magnetic sensors 4b, 4 attached to brackets 6b, 6c fixed to rings 5b, 5c
c is in the inclination of 30 degrees to one side and around the magnetic sensor 4a of the central portion, and a magnetic sensor 4a of the central portion 90
Each of them is provided one by one by shifting the position in the front-back direction to the position rotated by degrees.

A specific example of the present invention will be described with reference to FIG. 2. Kerosene K and light oil G are collected in separate tanks 7 and 8, and are collected first and kerosene K is already collected in tank 7. Yes, and thereafter, a state in which light oil G is collected in the tank 8 is shown.

That is, after the light oil G supplied from the tanker 9 is stored in the pipeline 1, the valves 1 of the T pipelines 10 and 11
2 and 13 are closed, and the spherical pig 2 is introduced from one side of the pipe line 1. The spherical pig 2 is automatically rolled because the pipe body is inclined, and comes into close contact with a fixed position of the juice pipe 1d of the starting portion 1b. When it comes in close contact with the fixed position of the rejuvenation pipe 1d,
The start side valve 14 and the recovery side valve 15 are opened, the start side air supply pipe 16 valve 17 is opened, and the compressed gas is sent. At the same time, the discharge pipe 18 valve 19 is opened to advance the spherical pig 2. Then, the passage is confirmed by the magnetic sensor 4 on the starting side, and the light oil G in the pipe line 1 is collected in the tank 8 through the discharge pipe 18.

The principle that the spherical pig 2 travels in the pipe 1 is that the outer diameter of the spherical pig 2 is 3 to 5% of the inner diameter in the pipe 1.
The back pressure is maintained by the sealing property, and the light pressure G is discharged by moving inside the main pipe 1 by the differential pressure. Since the magnetic field lines are emitted from the built-in permanent magnets 3 and 3 in the spherical pig 2 during the transition process, the magnetic field lines are detected by the magnetic sensor 4 and the passage can be confirmed.

The lines of magnetic force exit from the north pole and flow to the south pole, but are not uniformly emitted from all positions.
There is a strong part where the lines of magnetic force are concentrated at the center of the magnetic pole, and a demagnetizing part where the magnetic force is weak between the magnetic pole and the magnetic pole.In addition, since the pig is spherical, the direction of the magnetic lines changes due to the forward rotation, Although one magnetic sensor attached to the outer surface of the pipeline 1 does not detect that the demagnetizing portion passes by chance, in the present invention, the magnetic sensor 4 is displaced in the length direction and the circumferential direction of the pipeline 1. As shown in FIG. 8, three magnetic sensors 4b, 4
Even if the demagnetizing part passes at the point c, the magnetic sensor 4 at the top
a can detect the line of magnetic force, and the top magnetic sensor 4a
The left and right magnetic sensors 4
The lines of magnetic force can be detected by b and 4c.

As soon as the spherical pig 2 advances in the pipe 1 and reaches the position of the magnetic sensor 4 on the collecting side and detects the passage, the valve 19 of the discharging pipe 18 is closed and the supply of the back pressure is stopped. . After that, the pressure in the pipe line 1 is released,
After confirming that the internal pressure is 0, the valve 15 on the collecting side is closed, the residual oil in the collecting section 1c is collected from the drain, and the spherical pig 2 is taken out. Instead of the above-mentioned means, it is also possible to automatically send the spherical pig 2 back to the starting portion 1b and stop it in the starting portion 1b.

According to the present invention, the passage of the spherical pig 2 is sensed by the above-described method. By adopting this sensing method, the cost of fluid transportation can be reduced, the efficiency of transportation can be improved, and the pipeline maintenance and safety can be achieved. Is what you can do.

Although the present invention has been described with respect to an example in which two kinds of fluids are sent through one pipeline and collected in separate tanks,
The present invention is not limited to these embodiments, and it goes without saying that various design changes can be made without departing from the gist of the invention.

[0023]

As described above, according to the method for detecting the passage of a spherical pig according to the present invention, when the spherical pig is inserted from one end, the pig automatically rolls into the rejuice pipe, and the pipe is introduced by introducing back pressure. Even when the demagnetizing part of the magnetic field line passes under the magnetic sensor when moving and moving on the road, the magnetic sensor installed with the position shifted in the length direction and the circumferential direction can reliably detect The movement can be confirmed. Therefore,
In the operation of discharging the fluid in the pipe, automation and unmanned operation can be performed, and the operation efficiency can be improved.

In addition, the spherical pig has two permanent magnets each having two disk-shaped two-sided poles, and is built in a longitudinally opposed manner close to the outer peripheral surface of the spherical pig. It becomes large and can reach the magnetic sensor provided on the outer surface of the pipe sufficiently and can reliably detect it, so that a detection error does not occur.

[Brief description of the drawings]

FIG. 1 is a side view of a pipe used in the present invention.

FIG. 2 is a simplified side view showing an embodiment of the present invention.

FIG. 3 is a perspective view showing a mounting portion of a magnetic sensor.

FIG. 4 is a simplified sectional view of a mounting position of a magnetic sensor.

FIG. 5 is a sectional view of a spherical pig.

FIG. 6 is a perspective view of a permanent magnet.

FIG. 7 is an explanatory diagram showing a flow of lines of magnetic force of a permanent magnet.

FIG. 8 is an explanatory diagram of a rotating state of a spherical pig.

9A and 9B are longitudinal sectional side views showing a conventional pig.

FIG. 10 is a vertical sectional side view showing a conventional spherical pig.

FIG. 11 is a longitudinal sectional front view showing a state where another spherical pig has come under a sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piping line 1b Starting part 1c Collection part 2 Spherical pig 3 Permanent magnet 4 Magnetic sensor

Claims (2)

(57) [Claims] 1. A pig having a starting portion and a collecting portion inclined obliquely downward at both ends thereof, a spherical pig which pushes and shifts a fluid from behind and introduces the fluid by shifting the spherical pig. In the construction method, two permanent magnets are built in the pig at a predetermined interval, and the lines of magnetic force flowing from the N pole to the S pole of the permanent magnet during the movement process of the spherical pig are formed in a pipe line. Magnetic sensor provided at a predetermined position
And detecting at least one magnetic sensor attached to the pipe line at a position shifted from the magnetic sensor. 2. A disk-shaped permanent magnet consisting of two poles on both sides,
Near the outer peripheral surface at a certain distance from the center of the spherical pig,
The method for detecting passage of a spherical pig according to claim 1, wherein the method is performed by using a spherical pig that is built in opposite to the vertical direction.