Pipe pitch three measuring head measuring instrument and measuring method

Abstract

The application provides a pipe pitch three-probe measuring instrument and a measuring method, which comprises a first fixed probe, a second fixed probe, a movable probe and a displacement measuring tool; the first fixed probe and the second fixed probe are fixedly connected, and the movable probe is located on the perpendicular bisector of the line connecting the first fixed probe and the second fixed probe; the movable probe can move along the perpendicular bisector of the line connecting the first fixed probe and the second fixed probe; and the displacement measuring tool is used for measuring the moving distance of the movable probe. The three-probe measuring instrument does not need to swing on both sides of the measuring line, directly places the three probes in the pitch standard block, takes the standard pitch as the reference, then places the three probes in the corresponding thread grooves of the pipe to be measured, carries out corresponding compensation on the measuring result, and realizes the contact one-time measurement of the pipe pitch deviation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of oil pipe measurement, and relates to a portable pipe thread three-measuring-head measuring instrument and a measuring method, in particular to a measuring tool for oil pipe thread parameters. BACKGROUND

[0002] The oil pipe is subjected to external force combined load in the well, and the thread connection part is prone to failure, so it is necessary to detect the thread parameters. At present, the oil cone pipe thread pitch is measured by placing the front and rear measuring heads (fixed measuring head and movable measuring head) of the measuring tool in the standard pitch block, taking the standard pitch as the reference, then placing the fixed measuring head of the measuring tool in the corresponding thread groove of the pipe to be measured, and then swinging the front movable measuring head in the corresponding thread groove on both sides of the measuring line, and the minimum or maximum reading of the measuring instrument is the deviation of the pitch of the pipe to be measured from the standard pitch.

[0003] The existing oil cone pipe thread pitch two-measuring-head measurement has the following problems: with the digitization and automation of the current measuring instruments and equipment, the equipment needs to imitate the manual operation of the measuring head to swing on both sides of the measuring line, which not only affects the measurement efficiency, but also is difficult to obtain the pitch deviation by using the existing two-measuring-head pitch measuring instrument without manual operation. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art, and provides a pipe thread three-measuring-head measuring instrument and a measuring method, which does not need to swing on both sides of the measuring line, but directly places the three measuring heads in the standard pitch block, takes the standard pitch as the reference, then places the three measuring heads in the corresponding thread groove of the pipe to be measured, and compensates the measurement results accordingly to realize one-time contact measurement to obtain the pipe thread pitch deviation.

[0005] The present application is realized by the following technical solutions:

[0006] A pipe thread three-measuring-head measuring instrument, comprising: a first fixed measuring head, a second fixed measuring head, a movable measuring head, and a displacement measuring tool.

[0007] The first fixed measuring head and the second fixed measuring head are fixedly connected, and the movable measuring head is located on the perpendicular bisector of the line connecting the first fixed measuring head and the second fixed measuring head.

[0008] The movable measuring head can move along the perpendicular bisector of the line connecting the first fixed measuring head and the second fixed measuring head; and the displacement measuring tool is used to measure the moving distance of the movable measuring head.

[0009] Preferably, the displacement measuring tool is a micrometer.

[0010] Further, it further comprises a frame, and the first fixed measuring head and the second fixed measuring head are fixed on the frame.

[0011] Further, a guide rail is arranged on the frame, and the movable measuring head is slidably arranged on the guide rail of the frame.

[0012] Further, the displacement measuring tool is a micrometer, and the micrometer is fixedly installed on the frame; the measuring rod of the micrometer is parallel to the guide rail; and the movable measuring head is in contact with the measuring head of the micrometer.

[0013] The measuring method of the pipe thread pitch three-measuring head measuring instrument comprises the following steps: placing the first fixed measuring head, the second fixed measuring head and the movable measuring head on a pitch standard block, adjusting the distance between the midpoint of the line connecting the first fixed measuring head and the first fixed measuring head and the movable measuring head to a standard pitch, then placing the first fixed measuring head and the first fixed measuring head in a thread groove at a measuring starting end of a pipe to be measured, moving the movable measuring head along a thread axis of the pipe to be measured to a thread groove at a measuring terminal end, and measuring the moving distance of the movable measuring head by a displacement measuring tool, so as to obtain a deviation A of the thread pitch of the pipe to be measured from the standard pitch, and compensating the deviation A according to a thread helix angle to obtain an actual pitch deviation of the pipe to be measured after compensation.

[0014] Preferably, the pitch compensation amount AS for compensating the deviation A according to the thread helix angle is obtained according to the following formula:

[0015]

[0016] Wherein, T is the thread taper; D is the thread pitch diameter of the measuring starting end of the pipe to be measured; N is the number of thread teeth corresponding to the standard pitch B of the pipe to be measured; M is the distance between the first fixed measuring head and the second fixed measuring head, and B is the standard pitch.

[0017] Further, B is 25.4 mm.

[0018] Further, the actual pitch deviation of the pipe to be measured is A-AS.

[0019] Further, for the pipe with API standard thread, the corresponding table of the nominal outer diameter of the pipe and the pitch compensation amount AS is shown in Table 1.

[0020] Table 1 Pitch compensation amount of API standard thread

[0021] Pipe nominal outside diameter (mm) Pitch compensation (mm) 114.30 0.0138 127.00 0.0113 139.70 0.0094 168.28 0.0066 177.80 0.0060 193.68 0.0052 244.48 0.0035 .

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] The portable pipe pitch three measuring head measuring instrument of the present application comprises three measuring heads, two fixed measuring heads and one movable measuring head, when in use, the three measuring heads are placed in the pitch standard block, taking the standard pitch as the reference, then the first fixed measuring head and the second fixed measuring head are placed in the thread groove at the measuring starting end of the pipe to be measured, the movable measuring head is fine-tuned and placed in the thread groove, the three-point measurement positioning is stable, swing measurement is not necessary, the pitch deviation of the measured thread is obtained by one operation, and the efficiency is significantly improved. The measuring instrument is a handheld portable measuring instrument, has low environmental requirements, can meet the on-site detection of oil fields and pipe plants, can be combined with automatic equipment to realize automatic measurement, and has wide applicability. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a schematic diagram of the measuring instrument of the present application;

[0025] Figure 2 is a measurement principle diagram provided by the embodiment of the present application;

[0026] Figure 3 is a mathematical principle diagram provided by the embodiment of the present application;

[0027] The meanings of the symbols in the figure are as follows:

[0028] 1-first fixed measuring head; 2-second fixed measuring head; 3-movable measuring head; 4-micrometer. DETAILED DESCRIPTION

[0029] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0030] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0031] The application will be described in further detail below with reference to the drawings:

[0032] As Figures 1-3 The portable pipe thread three-probe measuring instrument comprises a first fixed probe 1, a second fixed probe 2, a movable probe 3 and a displacement measuring tool.

[0033] The first fixed probe 1 and the second fixed probe 2 are fixedly connected, and the movable probe 3 is located on the perpendicular bisector of the line connecting the first fixed probe 1 and the second fixed probe 2.

[0034] The movable probe 3 can move along the perpendicular bisector of the line connecting the first fixed probe 1 and the second fixed probe 2; and the displacement measuring tool is used for measuring the moving distance of the movable probe 3.

[0035] In one specific embodiment of the application, the displacement measuring tool is a micrometer 4.

[0036] In one specific embodiment of the application, a frame is further included, the first fixed probe 1 and the second fixed probe 2 are directly fixed on the frame, and the micrometer 4 is fixedly installed on the frame; a guide rail is arranged on the frame, a measuring rod of the micrometer 4 is parallel to the guide rail; the movable probe 3 is slidingly arranged on the guide rail of the frame, the movable probe 3 is in contact with a measuring head of the micrometer 4, and the displacement amount of the movable probe 3 is directly reflected to the change of the numerical value of the micrometer 4, i.e. the positive or negative deviation from the standard pitch.

[0037] The working process of the application is as follows:

[0038] Before measurement, the first fixed probe 1, the second fixed probe 2 and the movable probe 3 are placed on a pitch standard block, the distance between the midpoint of the line connecting the first fixed probe 1 and the second fixed probe 2 and the movable probe 3 is adjusted to the standard pitch, then the measurement of the thread pitch of the pipe to be measured is started, the first fixed probe 1 and the second fixed probe 2 are placed in the thread groove at the measurement starting end of the pipe to be measured, the movable probe 3 moves along the thread axis of the pipe to be measured, and is adjusted according to the orientation of the thread pitch diameter line of the pipe to be measured, so as to be placed in the thread groove at the measurement terminal end, the relative distance of the movable probe 3 is directly read by the micrometer 4, the numerical value of the micrometer 4 is recorded, and the actual pitch deviation of the thread to be measured is obtained in combination with the pitch compensation amount ΔS.

[0039] The pitch compensation amount ΔS is calculated according to the following formula:

[0040]

[0041] Wherein, T is the thread taper; D is the thread pitch diameter of the measurement starting end of the pipe to be measured; N is the number of thread teeth corresponding to the standard pitch B of the pipe to be measured; M is the distance between the first fixed probe 1 and the second fixed probe 2; and B is the standard pitch, for example, 25.4 mm.

[0042] Let the value of the dial gauge 4 be A, then the pitch deviation of the thread to be measured is: A-△S.

[0043] Mathematical principle of the present application:

[0044] When measuring with three probes, the actual measurement axis will be offset due to the helix angle, and the movable probe 3 will be offset to the position of 3', i.e. not in the axial direction of the oil cone pipe, as shown in the figure. Therefore, the actual measurement value needs to be compensated, and the mathematical principle is to convert the distance in the actual measurement direction to the distance in the thread generatrix direction, i.e. to obtain the length L2 from the known length L (the reading of the measurement tool + the standard pitch), as shown in the figure. Now map L to the axial direction of the pipe to be measured to obtain L1, and then map L1 to the generatrix direction of the pipe to be measured to obtain L2. The specific derivation process is not described here. This formula is a fuzzy processing for intuitively reflecting the influence of known variables on the offset. Figure 2 Figure 3

[0045] In particular, when measuring the API casing standard thread pitch using the method of the present application, a corresponding table of pipe nominal outer diameter and pitch compensation amount is given for convenience of inquiry, as shown in Table 1. Since D in the compensation formula is the thread pitch diameter of the starting end of the pipe to be measured, the pitch compensation amount in Table 1 is approximately processed, and the user can also directly substitute the pitch diameter of the starting end of the API standard thread into the formula for calculation. Since the outer diameter of the oil cone pipe is small, it has a greater impact on the offset, and the starting end pitch diameter value of the pipe to be measured should be used for calculation, and the nominal outer diameter is not suitable for direct inquiry.

[0046] Table 1 API standard thread pitch compensation amount

[0047] Pipe nominal outside diameter (mm) Three-point pitch compensation (mm) 114.30 0.0138 127.00 0.0113 139.70 0.0094 168.28 0.0066 177.80 0.0060 193.68 0.0052 244.48 0.0035

[0048] The above formula is not limited to various standard threads, and for special threads such as cone pipe threads, the pitch deviation can be compensated according to the formula of the present application.

[0049] The portable pipe thread three-probe measuring instrument of the present application measures the pitch deviation of the thread to be measured through the contact of the three probes with the surface of the thread to be measured, and the measurement is stable and does not need to be swung. One operation can measure the pitch deviation of the thread to be measured, and the efficiency is significantly improved. The measuring instrument is a handheld portable measuring instrument, has low environmental requirements, can meet the on-site detection of oil fields and pipe plants, and has wide applicability.

[0050] The above content only illustrates the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made on the basis of the technical solution according to the technical idea of the present application falls within the protection scope of the claims of the present application.​​

Claims

1. A method of measuring with a pipe thread pitch three-probe measuring instrument, characterized in that, The pipe pitch three probe measuring instrument is characterized in that it comprises a first fixed probe (1), a second fixed probe (2), a movable probe (3) and a displacement measuring tool; the first fixed probe (1) and the second fixed probe (2) are fixedly connected, and the movable probe (3) is located on the perpendicular bisector of the line connecting the first fixed probe (1) and the second fixed probe (2); the movable probe (3) can move along the perpendicular bisector of the line connecting the first fixed probe (1) and the second fixed probe (2); and the displacement measuring tool is used for measuring the moving distance of the movable probe (3); The first fixed probe (1), the second fixed probe (2) and the movable probe (3) are placed on the pitch standard block, the distance between the midpoint of the line connecting the first fixed probe (1) and the second fixed probe (2) and the movable probe (3) is adjusted to the standard pitch, then the first fixed probe (1) and the second fixed probe (2) are placed in the thread groove at the measurement starting end of the pipe to be measured, the movable probe (3) is moved to the thread groove at the measurement terminal end along the thread axis of the pipe to be measured, and the moving distance of the movable probe (3) measured by the displacement measuring tool is the deviation A of the thread pitch of the pipe to be measured from the standard pitch; the deviation A is compensated according to the thread helix angle, and the actual pitch deviation of the pipe to be measured is obtained after compensation; the actual pitch deviation of the pipe to be measured is A-△S; The pitch compensation amount △S for compensating the deviation A according to the thread helix angle is calculated according to the following formula: Wherein, T is the thread taper; D is the thread pitch diameter of the measurement starting end of the pipe to be measured; N is the number of thread teeth corresponding to the standard pitch B of the pipe to be measured; M is the distance between the first fixed probe (1) and the second fixed probe (2), and B is the standard pitch.

2. The method of measuring a pipe run with a pipe run three-measurement head measuring instrument according to claim 1, characterized in that, B is 25.4 mm.

3. The method of measuring a pipe run according to claim 1, wherein, For the pipe with API standard thread, the corresponding table of the nominal outer diameter of the pipe and the pitch compensation amount △S is shown in Table 1, Table 1 Pitch compensation amount of API standard thread 。 4. The method of measuring a pipe run according to claim 1, wherein, The frame is further provided, and the first fixed probe (1) and the second fixed probe (2) are fixed on the frame.

5. The method of measuring a pipe run according to claim 1, wherein, A guide rail is arranged on the frame, and the movable probe (3) is slidingly arranged on the guide rail of the frame.

6. The method of measuring a pipe run according to claim 1, wherein, The displacement measuring tool is a dial gauge (4), and the dial gauge (4) is fixedly installed on the frame; the measuring rod of the dial gauge (4) is parallel to the guide rail; and the movable probe (3) is in contact with the measuring head of the dial gauge (4).

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