JPS61296201A - Apparatus for automatically measuring film thickness of coated steel pipe - Google Patents

Abstract

PURPOSE:To make it possible to measure the thickness of a film with good accuracy, by allowing a detector to follow the surface of a shaking coated steel pipe by using a coil spring and an air cylinder. CONSTITUTION:A movable truck 2 is arranged on a rail crossing a feed direction at right angles and a traversing pedestal 36 freely traversing in parallel to a pipe axial direction is provided on said truck 2. A base 10 for an arm is provided on said pedestal 36 through a lift apparatus and a sensor arm 17 is provided to said base 10 through movable fulcrums 18, 19 while the fulcrum 18 is fixed to the base 10 through an air cylinder 14. A base 32 for a touch roll is provided to the upper surface of the leading end part 17' of the arm 17 through a movable fulcrum 21 and coil springs 22, 23 are further arranged to said base 32. A measuring roll 24 is provided on the base 32 through a coil spring 37 and a support shaft 35 and touch rolls 25, 26 are provided on said base 32 through support shafts 33, 34. A contact roll equipped with a pair of film thickness measuring detectors and a pair of differential transformers is mounted on the support shaft 35 and the rolls 24-26 pressed to the surface of a coated steel pipe follow the movements in directions shown by arrows 50, 51, 58, 59 to hold contact with respect to shaking during feed.

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 a steel pipe to be traversed during transportation.

(Prior art) When coating the outer surface of a large-diameter steel pipe with a diameter of 400 to 1,500φ with a non-conductive substance, such as polyethylene resin, to a thickness of 1.5 to 100 g, the steel pipe and polyethylene should each be heated to around 300°C. The process involves heating and winding semi-molten sheet polyethylene around a rotating steel pipe in a helical pattern.

After the coated steel pipe is water-cooled, the thickness of the polyethylene resin film is measured in the finishing process using a portable electromagnetic thickness gauge, and the two people work together to record the thickness of the polyethylene resin film. Spot measurements were carried out at a total of 12 points, 4 points in the circumferential direction at the top and middle bottom portions of the steel pipe in the longitudinal direction, but there were the following drawbacks.

(2) The number of measurement points was small and the average value was not necessarily the representative film thickness. (2) During the measurement, the steel pipe was stopped and rotated/s4 in the longitudinal direction of the pipe, which was inefficient.

(Problems to be solved by the invention) In order to solve the above-mentioned problems, the present invention uses coated steel pipes. The present invention provides an automatic film thickness measuring device having a tracking device capable of responding to the movement of a steel pipe during online transportation during the transportation process after water cooling.

(Means for Solving Problems) The apparatus of the present invention to achieve the above-mentioned object includes a traversing frame that can freely traverse in a direction perpendicular to the traveling direction of the bogie, which is mounted on a bogie that moves in a direction perpendicular to the direction of conveyance of the steel pipe to be traversed; An arm base is provided on the mount 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 rod of the cylinder is attached to the other end of the base. The tip and the end of the sensor arm are connected via a pin, and the sensor arm is cantilever-supported so as to be rotatable in the vertical direction using the connecting rod and the pin as rotational fulcrums. A touch roll base is installed on the top via a connecting rod,
In order to hold the base horizontally and tiltably, 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 steel pipe conveying direction, and the connecting rod is mounted on the base. A measuring roll that can freely rotate horizontally on a vertical axis is provided via a measuring roll support shaft that can freely move vertically, and a pair of measuring rolls are installed at a skewed position at the same distance from the measuring roll in a direction perpendicular to the steel pipe conveying direction. A touch roll is provided horizontally rotatably via a touch roll support shaft, and a pair of detectors for measuring coating thickness are provided at symmetrical positions spaced the same distance from the measuring roll support shaft in the steel pipe conveying direction. A contact roll equipped with a differential transformer for detecting the film lap portion is installed at a height position that maintains a non-contact state with the horizontal steel pipe, and further upstream in the steel pipe transport direction at approximately the same height as the measuring roll. The film thickness measuring point is kept at a constant position by moving the traversing frame, and each roll can follow the surface of the steel pipe to be traversed even when the steel pipe to be traversed swings in any direction during conveyance. This is an automatic film thickness measurement device for horizontal steel pipes.

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

Measurement accuracy of resin thickness of coated steel pipes being transported is ±0,1
In order to achieve a measurement of 1u or less, the resolution of the measuring device must be 115, which is about 0.02g or less, but the steel pipe to be traversed shakes violently during transportation, and the film thickness measurement detector (eddy current displacement meter) is difficult to use. This is because highly accurate measurements cannot be made unless it is always at a constant distance from the resin film surface of the steel pipe to be traversed. 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 turning roll, and small movements during transportation. It turns out that it can be classified into large horizontal movements and vertical movements. The present invention utilizes a single coil spring for small movements,
We have also discovered that for large movements, by using the coil spring and an air spring using an air cylinder, it is possible to accurately follow the swinging motion of the steel pipe that combines the detector.

(Structure of the invention) The basic functions of the device of the present invention are shown in Fig. 1 (a), (b), and (c).
The explanation will be based on. The steel pipe P to be traversed is sent in the pipe 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 perpendicular to the conveyance line. A traversing frame 36 is provided on the trolley 2 and is capable of traversing freely in a direction 54 (parallel to the tube axis direction) perpendicular to the direction of travel of the trolley 53,
An arm base 1o is provided above the transverse frame 36 via a lifting device that moves the arm base 10 up and down 52, and the arm pace 10 has a movable fulcrum 19 with a height of J''' when viewed from the front. A ``''-shaped sensor arm 17 is provided in a cantilevered manner. The movable fulcrum 1B is the air cylinder 14
The cylinder part 14 is fixed by a cylinder arm 13 attached to the end of the arm base 10. The sensor arm 17 is moved to a movable fulcrum 19 by the movement of the air cylinder 14 (arrow 58).
It is freely rotatable in the vertical direction (arrow 59) around . A touch roll 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 springs 22 are installed at symmetrical positions on the arm tip 17' at the same distance from the movable fulcrum 21 in the direction perpendicular to the path line.
．． When the touch rolls 25 and 26 are not in contact with the steel pipe to be traversed, the touch roll base 32 is kept horizontal, and when the touch rolls 25 and 26 are in contact with the steel pipe and the steel pipe swings, the base 32 is moved to the movable fulcrum 21. It is possible to tilt (arrow 51) around the center and hold it. A measuring roll 24 is mounted on the base 32.
is horizontally rotatable and vertically moved by the coil spring 37 (
Arrow 50) A pair of membranes is attached to the tip of the freely adjustable measuring roll support shaft 35, 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 steel pipe to be traversed. Thickness measurement detector s1, s2
and a contact roll 39 provided with a differential transformer 38 on the upstream side in the tube axis direction 55 are integrally attached to the measuring roll support shaft 35. Also, touch roll base 3
On top of the measuring roll 24, a pair of touch rolls 25 and 26 are placed at a skewed position, the same distance away from the measuring roll 24 in a direction perpendicular to the tube axis direction 55, and are horizontally rotatable at a higher position than the measuring roll 24. Touch roll support shaft 3
3.34.

The movement of this device having such a configuration is such that movement in the direction of arrow 53 releases the entire film thickness measuring device from the conveyance line in a direction perpendicular to the conveyance line, performs calibration, maintenance, etc., and returns it to a predetermined position on the conveyance line for measurement. The movement indicated by the arrow 54 is a movement to move the transverse mount in the tube axis direction 55 based on the measurement results of the differential transformer 3 days ago, so that the contact roll 39 is always at the lap part of the coating. automatically follows.

The movement of the arrow 52 is to set the initial height of the device in accordance with the bottom position 5 of the steel pipe P to be traversed, which changes depending on the size of the steel pipe P to be traversed, and to move the loading device on the arm base 10 up and down. It is a movement to do. The movement of the arrow 5 is the movement of the air cylinder 14 that presses the measuring roll 24, touch rolls 25, 26, and contact rolls 39 against the steel pipe P to be traversed, and also releases the pressure and prevents the swinging of the steel pipe during conveyance. In accordance with the following movement, the sensor arm 17 rotates in the vertical direction 59 about the movable fulcrum 19 due to the movement indicated by the arrow 58 . The movement 51 is the rotation of the touch roll base 32 from side to side around the movable fulcrum 21, and the movement shown by the arrow 50 is the vertical movement of the measuring roll 24, which follows the unevenness of the surface of the steel pipe. be. These arrows 5o,
51, 54, and 58 to follow the swinging of the steel pipe to be traversed during transportation.

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

First, manually move the trolley 2 that has been evacuated offline to the handle 9.
Press to move on the rail 1 in the direction of the conveyance line. The truck 2 stops when it comes into contact with the stopper 4, and the front and rear ends of the truck are fixed on the rail by the stoppers 4 and 5. 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 s1 and s2
, the contact roll 39 is automatically positioned to coincide with the center 55 of the conveying line. The top portion of the steel pipe P to be traversed, which is sent in the pipe axis direction while rotating on the conveyance line, is stopped on the apparatus when detected by a steel pipe detector (not shown).

First, the initial setting height of the device is adjusted in accordance with the steel pipe bottom position 57, which varies depending on the diameter of the steel pipe to be traversed. For adjustment, the arm base 10 is raised (or lowered) by turning the handle 6 provided on the transverse frame 36, rotating the shaft 7, bevel gear 8.8', and vertical screw 9. This is done by sliding the guide bar 11, which is attached to the lower surface of the four guide sleeves 12 arranged on the transverse frame 36 and the arm base 10, and is fitted into the guide sleeves 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 screw through the shaft 40, bevel gearbox 28 and coupling 41. In rotating the shaft 29,
As a result, the transverse frame 36 attached via the two slide shafts 30 and 31 is moved parallel to the tube axis direction 55. The movement of the traversal pedestal 36 allows all the devices loaded on the pedestal to traverse, and the contact roll 39 is placed on the lap of the coating. When the contact roll 39 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 this measuring roll is continuously measured in a spiral manner. be.

Next, when the piston 15 of the air cylinder 14 receives a downward force from the compressed air, the sensor arm 17, which is f-shaped when viewed from the front, moves between the connecting pin 18, which is a movable fulcrum, and the connecting rod 1.
9, the measuring roll 24, touch rolls 25, 26, and contact roll 39 loaded on the tip 17' of the sensor arm 17 are pressed against the lower surface of the steel pipe to be traversed, and pressed with a constant pressure. Then, by turning the handle 6 and raising the arm base 10, the inclined sensor arm 17 is raised until it becomes horizontal and the position is adjusted, thereby completing the preparation for measurement.

From now on, when preparing for measurement in the case of the same diameter, at the same time as the measurement of the first steel pipe P is completed, the sensor arm 1 is
7 to wait, and when the tip of the material is directly above the device, rotate the sensor arm 17 upwards to remove the steel pipe P.
Just press it. In the case of steel pipes with different diameters, the same operations are performed starting from the initial setting height adjustment as described above.

The front shape of the sensor arm 17 is as shown in Figure 2 (a)! Although it has a shape, it may be flat.

However, a flat shape has the disadvantage that the device becomes too large.Therefore, in order to make the device of the present invention as compact as possible, the sensor arm 17 is shaped into an f-shape in order to keep the height low.

Further, a balance weight 16 for balancing the arm is provided at the end of the sensor arm 17 on the cantilever side.

The connecting rod 19, which is a movable fulcrum, is connected to a supporting base 20 provided on both sides of the sensor arm 17 at one end of the upper surface of the arm base 10.
．． 20' via bearings 42, 42'.

The film thickness measurement detectors S8 and S2 attached to the measuring roll support shaft 35 are arranged at symmetrical positions on the center of the conveyance line at the same distance from the measuring roll 24, and maintain a non-contact state with the film. Therefore, it is placed at a low position a certain distance away from the top surface of the measuring roll 24. In the case of a UO steel pipe where the weld is straight in the direction of the tube axis, the above arrangement is sufficient, but in the case of a spiral steel pipe, the weld is in a helical shape, so the detector should 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 steel pipe P to be weaved that is ready for measurement is transported while being rotated in the pipe axis 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 steel pipe P in the axial direction, Due to shape changes and irregularities on the pipe surface, the steel pipe P is tilted vertically, horizontally, and in the direction of travel during transport, and due to a combination of these movements, the steel pipe P repeatedly moves and swings relative to the pass line and is transported. In response to these movements, the measuring roll 24 of this film thickness measuring device is pressed against the surface of the steel pipe to be traversed.
, touch roll 25.26, contact roll 39 in the direction of the arrow 50, 51.59.5 by the movable fulcrum 18.19.21.
The movement of 8 follows the surface of the steel pipe to be traversed and maintains contact. The film thickness measurement detectors S3 and S2 are always oriented towards the tube axis and are capable of measuring the film thickness in the axial and horizontal directions.

Furthermore, although the contact roll 39 is displaced from the lap portion during the conveyance of the steel pipe P to be traversed, the differential transformer 38 provided in the roll 39 electrically captures the change in film thickness at the lap portion.
The traversing frame 36 is moved in the pass line direction and controlled so that the contact roll 39 is always on the lap portion.

The metal covered horizontal steel pipe P moves to the left as shown in Figure 1, and P'
When the touch roll 25 is in the position shown in FIG.
3 and the arm portion 17 pushed up by the air cylinder 14 receives the upward force, and the touch roll base 32
is slightly inclined. Measuring roll 24 even when tilted
Since the detectors S, , and S detect the intermediate position of the touch rolls 25 and 26 and follow them toward the axis of the transverse steel pipe P', accurate film thickness measurement is possible.

Next, a method for measuring film thickness will be explained with reference to FIGS. 3(a) and 3(b). The detectors (eddy current displacement meters) st and ``'t attached to the measuring roll support shaft 35 are separated by a distance of 1° in the tube axis direction, and by a distance h1 between the top surface of the detector and the top surface of the measuring roll 24. It is provided at a separate position and is linked to the vertical movement of the support shaft 35.

The detector does not react to the coating M (polyethylene), which is a non-conductive material, and the signal output of the detector is from the steel pipe P directly below the detector.
The value corresponds to the distance g from the surface of Coating thickness t
can be measured using the following formula % formula % (1). If the steel pipe P is horizontal, the detector 511S
The measured value g of 2 will be the same, and one detector may be used, but in reality, as described above, a relative inclination between the detector and the tube surface occurs due to rocking during transportation. Therefore, the distance g1 between the left and right detectors changes, causing an error in the film thickness measurement value t. Therefore, in the measurement method of the present invention, as shown in (b), the distance between the detectors Sl, S2 and the steel pipe surface is gla,
glb, and the apparent film thicknesses are tl and tb, so the film thickness t is determined by the following formula.

That is, by using the average value of the signal outputs of the two detectors SI and S2, even if there is a relative inclination between the detector and the tube surface, it is automatically corrected and the measuring roll 24
The film thickness t at the contact point A can be accurately measured.

(Example) The device of the present invention was applied to various polyethylene lateral steel pipes (UO steel pipes, spiral steel pipes, and electric resistance welded steel pipes), and the measurement conditions were: steel pipe outer diameter φ400 to 500, bend 1.5/1000, film thickness measurement range 1.5-7%, steel pipe peripheral speed 4-25m1m1n,
Spiral feed with shaft speed 1.5 m/ffJ 1fl,
Touch roll, measuring roll, contact roll Pressure force 4.5Ky/al on steel pipe Eddy current detector S1, S2
When measured at an interval of 10 ctn, the reproducibility γ = ±13
μ, linearity ε=±20μ, drift α=±10μ, and overall accuracy a=3γ+ε+α=69μ, 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 steel pipe to be traversed that swings during conveyance, and it has become possible to accurately measure the film thickness. In addition, since the device is pressed from the bottom of the steel pipe to be traversed, the size of the pipe can also be adjusted from φ400 to φ1.
500, the device was 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 the drawing]

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,
Figure (A) is a side view showing a completely cutaway cross section of the device of the present invention, and Figure (B) is a plan view of the device of the present invention. FIG. 3 is an explanatory diagram of film thickness measurement. 1...Rail 2Practice 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 fly 24...Measuring roll 25
, 26...Touch roll 29...Screw shaft
30.31...Slide shaft 32...Roll base for cod f 33.34...Touch roll support
Holding shaft 35...Measuring row 36...Transverse mount support shaft 37...Coil spring 38...Differential transformer 39...Contact roll 40...Shaft
41...Coupling 42.42'...
Bearing 57...Bottom position 52, 54.55
．． 56. ss...Arrow 17'...Tip of sensor arm Figure 1 (B) (C) Figure 2 (U)

Claims (1)

[Claims] An arm base is provided on a trolley that moves in a direction perpendicular to the direction of conveyance of the coated steel pipe, through a traverse 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 further 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 connected via a pin to connect the sensor. The arm is cantilever-supported so as to be able to rotate vertically using the connecting rod and pin as rotational fulcrums, and a touch roll base 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 steel pipe conveying direction so that it 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 touch rolls are placed horizontally at a skewed position, the same distance away from the measuring roll in a direction perpendicular to the steel pipe transport direction. A pair of detectors for measuring the coating thickness are installed at symmetrical positions that are the same distance away from the measuring roll support shaft in the steel pipe conveying direction and are in a non-contact state with the coated steel pipe. In addition, 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 is removed by the movement of the transverse frame. An automatic film thickness measuring device for a coated steel pipe, characterized in that the thickness measurement point is maintained at a constant position, and each of the rolls can follow the surface of the coated steel pipe when the steel pipe to be traversed swings in any direction during transportation.