JPH0370163B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic film thickness measuring device that accurately measures the film thickness of coated steel pipes during transportation.

(Conventional technology) A non-conductive material is placed on the outer surface of a large diameter steel pipe of 400 to 1500φ.
For example, when coating polyethylene resin to a thickness of 1.5 to 7 mm, coat the steel pipe and polyethylene with a thickness of 300 mm each.
The process involves heating a semi-molten sheet of polyethylene to around 30°F and winding it around a rotating steel tube in a helical shape.

After the coated steel pipes are water-cooled, the thickness of the polyethylene resin film is spotted during the finishing process using a portable electromagnetic thickness meter, a collaborative effort in which one person measures and the other records. Measurements were taken at a total of 12 points (4 points in the circumferential direction at the top and middle bottom in the longitudinal direction of the steel pipe), but the following drawbacks occurred.

It was inefficient because the number of measurement points was small and the average value was not necessarily the representative film thickness, and the measurement worker had to stop the steel pipe, rotate it in increments, and move in the longitudinal direction of the steel pipe.

In order to solve the above-mentioned problems, the present invention aims to solve the above-mentioned problems, such as the fact that the measured values include individual errors, and the labor required by two people. The purpose of the present invention is to provide an automatic film thickness measuring device that has a tracking device that can respond to the movement of a steel pipe being transported online during the transport process.

(Means for Solving Problems) The device of the present invention for achieving the above object includes a traversing frame that is movable in a direction perpendicular to the traveling direction of the coated steel pipe, and a traversing frame that is movable in a direction perpendicular to the traveling direction of the coated steel pipe. An arm base is provided on the top via a vertical movement device that moves the arm base up and down, a sensor arm is attached to one end of the upper surface of the base via a connecting rod, a cylinder is attached to the other end of the base, and the tip of the rod of the cylinder is attached. and the end of the sensor arm are connected via a pin, and the sensor arm is cantilever-supported so as to be freely rotatable in the vertical direction using the connecting rod and the pin as rotational fulcrums. A base for the Tatsuchi Roll is provided via a connecting rod, and a coil spring is attached to the tip of the sensor arm at a symmetrical position at the same distance from the connecting rod in a direction perpendicular to the steel pipe conveying direction so that the base can be held horizontally and tiltably. A measuring roll that is horizontally rotatable on the vertical axis of the connecting rod is provided on the base via a measuring roll support shaft that is vertically movable, and a measuring roll is provided on the base via a measuring roll supporting shaft that can freely move up and down. A pair of Tatsuchi rolls are installed at skewed positions, the same distance apart in the direction perpendicular to the measuring rolls, and are installed via a Tatsuchi roll support shaft so as to be rotatable in the horizontal direction, and at symmetrical positions the same distance away from the measuring roll support shaft in the steel pipe conveying direction. A pair of detectors that measure coating thickness are placed at a height that maintains non-contact with the coated steel pipe.
Furthermore, a contact roll equipped with a differential transformer for detecting the film lap portion is installed on the upstream side in the steel pipe transport direction at approximately the same height as the measuring roll, and the film thickness measurement point is maintained at a constant position by moving the transverse frame. , against the swinging of the coated steel pipe in any direction during transportation,
There is provided an automatic film thickness measuring device for a coated steel pipe, characterized in that each of the rolls is capable of following the surface of the coated steel pipe.

The need for the accurate tracking device of the present invention is as follows.

To reduce the measurement accuracy of the resin thickness of coated steel pipes to be transported to within ±0.1 mm, the resolution of the measuring device must be reduced to 1/5 of that of
However, coated steel pipes shake violently during transportation, and the film thickness measurement detector (eddy current displacement meter) must always be at a constant distance from the resin film surface of the coated steel pipe. This is because accuracy cannot be measured. Therefore, after disassembling the steel pipe swing and examining it in detail, we found that the causes of the swing were the unique swing due to the shape of the steel pipe, small movements such as the swing that occurs when the welded part (seam part) passes over the tanning roll, and the conveyance. It turns out that it can be classified into large horizontal movements and vertical movements. The present invention uses a single coil spring for small movements, and uses the coil spring and an air spring using an air cylinder for large movements, so that the detector can accurately follow the oscillation of the combined steel pipe. This is what I discovered.

(Structure of the Invention) The basic functions of the device of the present invention will be explained based on FIG. 1 A, B, and C. The coated steel pipe P is sent in the tube axis direction (arrow 55) while being rotated (arrow 56) on turning rolls (not shown) of the conveyance line by the rotation of the turning roll. The automatic film thickness measuring device is disposed so as to be movable on a rail 1 disposed in a direction 53 orthogonal to the conveyance line. A transverse pedestal 36 is provided on the cart 2 and is movable in a direction 54 perpendicular to the direction 53 of the cart (parallel to the tube axis direction). A movable fulcrum 1 is provided on the arm base 10 via a lifting device that moves the arm 52.
A sensor arm 17, which is cross-shaped when viewed from the front, is provided in a cantilevered manner via 8 and 19. The movable fulcrum 18 is connected by a piston rod 15 of an air cylinder 14, and the cylinder portion 14 is fixed by a cylinder arm 13 attached to the end of the arm base 10. The sensor arm 17 is rotatable vertically (arrow 59) about a movable fulcrum 19 due to the movement of the air cylinder 14 (arrow 58). A Tatsuchiroll base 32 is placed on the upper surface of the tip 17' of the sensor arm 17 via a movable fulcrum 21. A pair of coil springs 22 and 23 are arranged at symmetrical positions on the arm tip 17' at the same distance from the movable fulcrum 21 in the direction perpendicular to the pass line, and when the tatsuchi rolls 25 and 26 are not in contact with the coated steel pipe, Keep the roll base 32 horizontal,
Also, when the steel pipe swings in contact with the steel pipe, the base 3
2 can be tilted (arrow 51) and held around a movable fulcrum 21. On the base 32, a measuring roll 24 is mounted on a coil spring 3 so as to be rotatable in the horizontal direction.
7 is attached to the tip of the measuring roll support shaft 5 that can freely move up and down (arrow 50), and is placed at a symmetrical position the same distance away from the measuring roll support shaft 35 in the tube axis direction 55 so as to be in a non-contact state with the coated steel pipe. One film thickness measuring detector S ₁ , S ₂ is further integrally attached to a contact roll 39 equipped with a differential transformer 38 on the upstream side in the tube axis direction 55 and to the measuring roll support shaft 35 . Further, on the base 32 for the tatsuchi roll, a pair of tatsuchi rolls 25 and 26 are rotated horizontally to a position higher than the measuring roll 24 at the same distance from the measuring roll 24 in a direction perpendicular to the tube axis direction 55 and at a skewed position. It is movably provided on the Tatsuchi roll support shafts 33 and 34.

The movement of this device with such a configuration is indicated by arrow 5.
The movement in the three directions is the movement in which the entire film thickness measuring device is removed from the conveyance line in the right angle direction, calibration, maintenance, etc. are performed, and it is again set at a predetermined position on the conveyance line for measurement. , based on the measurement results of the differential transformer 38, the contact roll 3 is moved by moving the transverse frame in the tube axis direction 55.
9 is automatically tracked so that it always comes to the lap part of the film. The movement of the arrow 52 is to set the initial height of the device in accordance with the bottom position 57 of the coated steel pipe P, which changes depending on the size of the coated steel pipe P, and is the movement of moving the loading device on the arm base 10 up and down. be. The movement of the arrow 58 is the movement of the air cylinder 14, which moves the measuring roll 24 and the tatsuchi roll 2.
5, 26, this is a movement that presses the contact roll 39 against the coated steel pipe P, releases the pressure, or follows the swinging of the steel pipe during conveyance, and the movement of the above arrow 58 causes the sensor arm 17 to move to the movable fulcrum 19. Rotate 59 in the vertical direction around . The movement 51 is a movement in which the Tatsuchi roll base 32 rotates left and right about the movable fulcrum 21, and the movement shown by an arrow 50 is the vertical movement of the measuring roll 24, which follows the unevenness of the surface of the steel pipe. . these arrows 5
The motions of 0, 51, 54, and 58 follow the swinging of the coated steel pipe during transportation.

Further, the structure and operation of the apparatus of the present invention will be explained in detail with reference to FIG.

First, the trolley 2 that has been evacuated offline is moved by manually pushing the handle 3 on the rail 1 in the direction of the conveyance line. The cart 2 stops when it comes into contact with the stopper 4, and the front and rear ends of the cart are moved between the stoppers 4 and 5.
to fix it on the rail. The trolley does not necessarily need to run on rails, but may run on tires on the floor. Due to this fixation, the measuring roll 24, the film thickness detectors S ₁ and S ₂ , and the contact roll 39 are placed at positions that automatically coincide with the center 55 of the conveyance line. The top portion of the coated steel pipe P, which has been rotated on the conveyance line and sent in the pipe axial direction, is stopped on this apparatus by detection by a steel pipe detector (not shown).

First, the initial setting height of this device is adjusted in accordance with the steel pipe bottom position 57, which differs from the diameter of the coated steel pipe. For adjustment, the arm base 10 is raised (or lowered) by turning the handle 6 provided on the transverse frame 36 and rotating the shaft 7, bevel gears 8, 8', and vertical screw 9. Four guide sleeves 12 arranged on the transverse frame 36
This is done by sliding the guide bar 11 attached to the lower surface of the arm base 10 and fitted into the guide sleeve 12. As the arm base 10 rises or falls, all the loaded items on the base move up and down. The device, set at the initial height, then drives the motor 27 mounted on the trolley 2 in order to align the contact roll 39 with the coating lap, and drives the shaft 40, bevel gearbox 28 and coupling 4.
By rotating the screw shaft 29 through 1,
The transverse pedestal 36 attached via the two slide shafts 30 and 31 is moved parallel to the tube axis direction 55. Due to the movement of the transverse pedestal 36, all the devices loaded on the pedestal are the traversing pedestal, and the contact roll 39
is placed on the lap of the coating. Contact roll 3
When the measuring roll 9 is placed on the lap portion, the measuring roll 24 is positioned approximately at the center between the laps, and the film thickness at the position of the measuring roll is continuously measured in a spiral manner.

Next, when the piston 15 of the air cylinder 14 receives a downward force from the compressed air, the sensor arm 17, which is curved when viewed from the front, rotates upward via the connecting pin 18 and connecting rod 19, which are movable fulcrums, and Measuring roll 24 and Tatsuchi roll 2 loaded on the tip 17' of arm 17
5, 26, the contact roll 39 is pressed against the lower surface of the coated steel pipe with a constant pressure. Then, by turning the handle 6, the arm base 10 is raised, and the tilted sensor arm 17 is raised until it becomes horizontal, the position is adjusted, and the measurement preparation is completed.

From now on, when preparing for measurement when the diameter is the same, use the first steel pipe P.
At the same time as the direction of travel ends, the air cylinder 14
Then, all that is required is to rotate the sensor arm 17 downward and wait, and when the tip of the material comes directly above the device, rotate the sensor arm 17 upward and press it against the steel pipe P. In the case of steel pipes with different diameters, the same operations are performed starting from the initial setting height adjustment as described above.

Although the front shape of the sensor arm 17 is curved as shown in FIG. 2A, it may also be flat. However, a flat shape has the disadvantage that the device becomes too large, so in order to make the device of the present invention as compact as possible, the sensor arm 17 is shaped like a square in order to keep the height low.

Additionally, a balance weight 16 is provided at the cantilever side end of the sensor arm 17 to balance the arm.
is provided. The connecting rod 19, which is a movable fulcrum, is connected to the sensor arm 1 at one end of the upper surface of the arm base 10.
Bearings 42, 20, 20' provided on both sides of the
42'.

The film thickness measurement testers S ₁ and S ₂ attached to the measuring roll support shaft 35 are arranged at symmetrical positions on the center of the conveying lie, the same distance away from the measuring roll 24, and maintain a non-contact state with the film. For,
It is arranged at a low position a certain distance away from the top surface of the measuring roll 24. In the case of UO steel pipes where the weld is straight in the direction of the tube axis, the above arrangement is sufficient, but in the case of spiral steel pipes, the weld is in a helical shape, so the detector must be placed parallel to the helix of the weld. It is used by tilting it with respect to the tube axis direction so that the

The coated steel pipe P that is ready for measurement is transported while being rotated in the pipe axial direction 55 by turning rolls (not shown), but there are some problems such as contact of the welded part with the turning roll, bending of the coated steel pipe P in the axial direction, and the pipe surface. Due to shape changes and irregularities, the steel pipe P tilts vertically, horizontally, and in the direction of travel during transportation, and due to these combined movements, the steel pipe P repeatedly moves and oscillates with respect to the pass line.
transported. In response to these movements, the measuring roll 24, tatsuchi rolls 25, 26, and contact roll 3 of this film thickness measuring device are pressed against the surface of the coated steel pipe.
9 is moved in the direction of the arrow 5 by movable fulcrums 18, 19, and 21.
0, 51, 59, 58 movements to follow the coated steel pipe surface and maintain contact. Instrument for measuring film thickness
S ₁ and S ₂ always face the tube axis, and the film thickness in the axial direction can be measured.

Furthermore, although the contact roll 39 is displaced from the lap part while the coated steel pipe P is being conveyed, the differential transformer 38 provided in the roll 39 electrically detects the change in film thickness at the lap part and moves the traversing frame 36. It moves in the direction of the pass line and is controlled so that the contact roll 39 is always on the lap portion.

Now, if the coated steel pipe P moves to the left as shown in Fig. 1 and reaches the position P', the Tatsuchi Roll 25 will receive a downward force, and the Tatsuchi Roll 26 will move from the movable fulcrum 2.
1, the spring 23, and the arm portion 17 pushed up by the air cylinder 14, the Tatsuchi Roll base 32 is slightly inclined. Measuring roll 24 and detector even if tilted
Since S ₁ and S ₂ detect the intermediate position between the tatsuchi rolls 25 and 26 and follow them toward the axis of the coated steel pipe P', accurate film thickness measurement is possible.

Next, the method for measuring film thickness will be explained with reference to FIGS. 3A and 3B. The detectors (eddy current displacement meters) S ₁ and S ₂ attached to the measuring roll support shaft 35 are separated by a distance l ₀ in the tube axis direction, and the distance between the top surface of the detector and the top surface of the measuring roll 24 is h ₁ The support shaft 35 is provided at a position apart from the support shaft 35, and is adapted to move in conjunction with the vertical movement of the support shaft 35. The detector is a coating M which is a non-conductive material.
It does not react to (polyethylene), and the signal output of the detector is determined by the distance from the surface of the steel pipe P directly below the detector.
The value corresponds to g ₁ . The coating thickness t can be measured using the following formula: t=g ₁ −h ₁ (1). If the steel pipe P is horizontal, the detector
The measured values g ₁ of S ₁ and S ₂ will be the same, and one detector may be used, but in reality, as mentioned above, due to the rocking during transportation, a relative tilt between the detector and the tube surface will occur. do. Therefore, the distance _g1 between the left and right detectors changes, causing an error in the film thickness measurement value t. Therefore, as shown in measurement method b of the present invention, the distances between the detectors S ₁ and S ₂ and the steel pipe surface are g _1a and g _1b , and the apparent coating thicknesses are t _a and t _b
Therefore, the film thickness t is determined by the following formula.

t = t _a + t _b /2 = g _1a + g _1b /2 - h ₁ ...(2) That is, by using the average value of the signal outputs of the two detectors S ₁ and S ₂ , the detector and tube surface can be Even if there is an inclination relative to the measuring roll 24, it can be automatically corrected and the film thickness t at the contact point A of the measuring roll 24 can be accurately measured.

(Example) The device of the present invention was applied to various polyethylene coated steel pipes (UO
(Steel pipes, spiral steel pipes, ERW steel pipes), the measurement conditions were steel pipe outer diameter φ400 to 500, bend 1.5/
1000, film thickness measurement range 1.5~7m/m, steel pipe circumferential speed 4~
Spiral feed at 25m/min, shaft speed 1.5m/min,
Tatsuchi roll, measuring roll, contact roll Pressing force on steel pipe 4.5Kg/cm ² Eddy current detector S ₁ , S ₂
When measured at an interval of 10 cm, repeatability γ = ±13 μ, linearity ε = ±20 μ, drift α = ±10 μ, and overall accuracy a = 3γ + ε + α = 69 μ, confirming high-precision tracking performance.

(Effects of the Invention) As explained above, according to the apparatus of the present invention, it is possible to accurately follow the surface of the coated steel pipe that swings during transportation, and it has become possible to accurately measure the film thickness. In addition, since the device is pressed from the bottom surface of the coated steel pipe, the size of the pipe can be from φ400 to φ1500, and the device is simple and compact. The operation rate of the finishing process has also improved, and in the past, the film thickness was made thicker than the specified value to account for measurement errors, but by being able to control the thickness to the specified value, the yield of the coating material (polyethylene) can be improved, among other things. It has the effect of

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the basic functions of the device of the present invention.
A is an explanatory diagram seen from the direction of the tube axis, B is an explanatory diagram seen from the direction parallel to the tube axis, C is an explanatory diagram seen from the top direction, and FIG. 2A is a side view showing a completely cutaway section of the device of the present invention , b are plan views of the device of the present invention. FIG. 3 is an explanatory diagram of film thickness measurement. 1...Rail, 2...Dolly, 4...Stopper, 5...Stopper, 6...Handle, 7...
Axis, 9...Vertical screw, 10...Arm base,
11... Guide sleeve, 12... Guide bar, 13... Cylinder arm, 14... Core cylinder, 16... Balance weight, 17...
Sensor arm, 18, 19, 21... Movable fulcrum, 20, 20'... Support stand, 22... Coil spring, 23... Coil spring, 24... Measuring roll, 25, 26... Tatsuchi roll, 29...
Screw shaft, 30, 31...Slide shaft, 32...Tatsuchi roll base, 33, 34...Tatsuchi roll support shaft, 35...Measuring roll support shaft,
36...Transverse mount, 37...Coil spring, 38...
...Differential transformer, 39...Contact roll, 40...
Shaft, 41...coupling, 42, 42' bearing,
57...Bottom position, 52, 54, 55, 56,
58...Arrow, 17'...Tip of sensor arm.

Claims (1)

[Claims] 1. An arm base is mounted on a trolley that moves in a direction perpendicular to the conveying direction of the coated steel pipe, through a transverse mount that can freely traverse in a direction perpendicular to the direction of travel of the trolley, and a vertical movement device that moves the arm base up and down on the mount. A sensor arm is attached to one end of the upper surface of the base via a connecting rod, a cylinder is attached to the other end of the base, and the tip of the rod of the cylinder and the end of the sensor arm are coupled via a pin. The sensor arm is supported in a cantilever manner so as to be able to rotate vertically using the connecting rod and pin as rotational fulcrums, and a base for the Tatsuchi roll is provided on the tip of the sensor arm via the connecting rod, and the base is horizontally and vertically supported. A coil spring is provided on the tip of the sensor arm at a symmetrical position at the same distance from the connecting rod in a direction perpendicular to the direction of conveyance of the steel pipe so that the sensor arm can be held tiltably, and a coil spring is provided on the base horizontally on the vertical axis of the connecting rod. A measuring roll that can freely rotate in the direction is provided via a measuring roll support shaft that can freely move up and down, and a pair of tatsuchi rolls are installed horizontally at a skewed position at the same distance from the measuring roll in the direction perpendicular to the steel pipe conveying direction. A pair of detectors for measuring the coating thickness are installed at symmetrical positions at the same distance from the measuring roll support shaft in the steel pipe conveying direction, while maintaining a non-contact state with the coated steel pipe. Furthermore, a contact roll equipped with a differential transformer for detecting the film lap portion is installed on the upstream side in the steel pipe transport direction at approximately the same height as the measuring roll, and the film thickness can be measured by moving the transverse frame. 1. An automatic film thickness measuring device for a coated steel pipe, characterized in that the rolls are able to follow the surface of the coated steel pipe when the coated steel pipe swings in any direction during conveyance by keeping the point at a constant position.