CN201075001Y - Device for detecting pipe wall thickness - Google Patents

Abstract

The utility model relates to a device for measuring the thickness of a pipeline wall. The detection device includes a signal collection device and an ultrasonic detection system and is characterized in that the signal collection device includes a measuring rod and a ladder-shaped ultrasonic probe; one end of the measuring rod is fixedly arranged with a probe positioning block which is cut with a probe hole; the large diameter end of the probe is arranged in the probe hole and affixed with the end surface of the measuring rod; a probe pressure block which is cut with a central ladder hole is arranged on the probe positioning block; the interior of the probe pressure block is provided with a spring; one end of the spring is arranged in the central ladder hole, while the other end is arranged on a ladder platform of the probe; the large diameter end of the probe is pressed and affixed on the contact end surface of the measuring rod; the small diameter end of the probe penetrates the spring and extends out of the probe pressure block; the other end of the measuring rod is arranged on a pipeline to be detected. The detection device has few parts and no special materials are needed; when in detection, the pipeline does not need to be cut with a hole; the structure is simple, the cost is low, and the popularization and application are easy.

Description

A detection device for pipe wall thickness

technical field

The utility model relates to an ultrasonic detection technology, in particular to a detection device for measuring the wall thickness of a pipeline using ultrasonic technology, especially a detection device for a high temperature and high pressure pipeline. The main classification number of the international patent is intended to be Int.

Background technique

The wall thickness of the pipe is related to the safety of its application, so the detection of the pipe wall thickness is of great significance no matter in the production process or in the use process. Relatively speaking, the detection of pipe wall thickness during use is more important and technically more difficult.

At present, there are two types of on-line wall thickness detection devices commonly used in high-temperature and high-pressure pipelines, one is a resistance corrosion probe, and the other is an ultrasonic thickness gauge. The first type of device needs to open holes in the high-pressure pipeline to install resistance corrosion probes, but the parts that need thickness measurement are mostly special parts such as elbows and tees, and opening holes in these parts will have a greater negative impact on the strength of the components . Ultrasonic thickness gauge is currently the most ideal thickness measuring device, but for the detection of high-temperature pipelines, it is necessary to install an insulation box at the measurement point of the pipeline wall thickness. It is troublesome to open the insulation box during measurement. Measurement also requires expensive high-temperature probes and high-temperature couplants.

Chinese patent CN2235603Y proposes a device for online monitoring of the wall thickness of the blast furnace lining by using a measuring rod and an ultrasonic probe. The metal measuring rod of this device is inserted into the high-temperature furnace lining and corroded together with the furnace lining. The ultrasonic probe is used to measure the length change of the measuring rod, and then the change of the furnace lining thickness is obtained. However, this device cannot be directly applied to the wall thickness detection of high-temperature and high-pressure pipelines. The main reason is It is still the problem of the opening of the high-pressure pipeline.

A number of US patents (US4783997, US7080556, US5951163) have proposed a device for measuring high-temperature objects using an ultrasonic buffer rod (Buffer Rod). These devices are mainly used to detect high-temperature fluid in pipelines or equipment. The buffer rod is mainly used as an ultrasonic waveguide, and it is proposed that the coating can effectively reduce the ultrasonic trailing echoes (trailing echoes), improve the signal-to-noise ratio, and propose a tapered The buffer rod has better wave guiding performance. However, some of the buffer rods in these devices need to penetrate into the container to monitor the high-temperature fluid in the equipment, which also involves the problem of opening holes; some need to add a special coupling device between the buffer rod and the high-temperature object to achieve measurement. The structure is complex and the cost is high.

Utility model content

Aiming at the deficiencies of the prior art, the technical problem to be solved by the utility model is to provide a detection device for the wall thickness of the pipeline. The detection device has a simple structure and low cost. It does not need to drill holes in the pipeline during detection and application, which does not affect the strength of the pipeline, and can use general ultrasonic probes and couplants to detect the wall thickness of the pipeline. It is especially suitable for the wall thickness of high-temperature and high-pressure pipelines. detection.

The technical solution of the utility model to solve the technical problem of the detection device is: to design a detection device for the wall thickness of the pipeline, which includes a signal acquisition device and an ultrasonic detection system, and is characterized in that the signal acquisition device includes a measuring rod and a stepped The ultrasonic probe is fixed with a probe positioning block with screws at one end of the measuring rod, and the probe positioning block has a probe hole; the large-diameter end of the ultrasonic probe is installed in the probe hole and fits with the end face of the measuring rod; the probe The pressing block is installed on the probe positioning block in a threaded manner. The probe pressing block has a central stepped hole, and a spring is installed in it. One end of the spring is installed in the central stepped hole, and the other end is installed in the step of the ultrasonic probe. on the platform, and press the large-diameter end of the probe on the contact end surface of the measuring rod; the small-diameter end of the ultrasonic probe passes through the spring and protrudes out of the probe pressing block; the other end of the measuring rod For installation on the pipeline to be inspected.

Compared with the prior art, the detection device of the pipe wall thickness of the utility model uses fewer parts, the measuring rod does not need special materials, and the detection application does not need to open holes in the detection part of the pipe, so the structure is simple, the cost is low, and it is easy to realize. It will not affect the strength of the pipeline, and there is no need to set up an insulation box, a high-temperature probe and a high-temperature couplant, so it is especially suitable for the detection of the wall thickness of high-temperature and high-pressure pipelines. It is convenient for promotion and application.

Description of drawings

Fig. 1 is the overall shape structure schematic diagram of a kind of embodiment of the detection device of the utility model (high temperature and high pressure) pipeline wall thickness;

Fig. 2 is a schematic diagram of the shape and structure of the probe pressing block of an embodiment of the utility model (high temperature and high pressure) pipeline wall thickness detection device.

Detailed ways

Below in conjunction with embodiment and accompanying drawing thereof, the utility model is further described:

The pipe wall thickness detection device (abbreviation detection device, referring to Fig. 1, 2) of the utility model design, it comprises signal collection device and ultrasonic detection system, is characterized in that described signal collection device comprises measuring rod 5 and stepped ultrasonic probe (be called for short probe) 10, be equipped with probe positioning block 7 with countersunk head screw 8 at one end of measuring rod 5, probe positioning block 7 has probe hole 14; The large-diameter end of ultrasonic probe 10 is installed in described probe hole 14 , and fit with one end face of the measuring rod 5 (the upper end face shown in Figure 1); the probe pressing block 9 is installed on the probe positioning block 7 in a threaded manner, and the probe pressing block 9 has a central stepped hole 15, A spring 11 is installed in it, and one end of the spring 11 is installed on the stepped platform in the central stepped hole 15, and the other end is installed on the stepped platform of the probe 10, and the large diameter end of the probe 10 is pressed and fitted On the contact end face with the measuring rod 5; the small diameter end (i.e. the lead wire end) of the probe 10 passes through the spring 11 and stretches out of the probe pressing block 9; the other end of the measuring rod 5 is used for installation on the pipeline being tested. The embodiment of the measuring rod 5 adopts a cylindrical design.

The further feature of the detection device of the present utility model is that the middle part of the measuring rod 5 is covered with a cooling assembly, including a sleeve 4 and an end cap 2 and a gland 1 matched with both ends thereof, between the gland 1 and the end cap 2 The sealing ring 3 is placed between them, the end cover 2 is welded with the sleeve 4, and the sealing and axial positioning of the cooling assembly can be realized by tightening the gland 1; the water inlet pipe interface 6 and the water outlet pipe interface 6 of the cooling water are arranged on the wall of the sleeve 4 '; The cooling assembly and the external cooling water pipeline circulation system (not shown in the figure) form the cooling device for the measuring rod 5. The cooling water is recycled, and the measuring rod 5 when measuring the high-temperature and high-pressure pipeline is cooled by using the circulating cooling water. The external cooling water pipeline circulation system is the prior art. This testing device with a cooling device is especially suitable for testing the wall thickness of high-temperature and high-pressure pipelines.

The cooling device described in the utility model is a detachable structural design, and the sleeve 4 of an appropriate length can be replaced according to the temperature of the measured pipeline 13, the temperature of the circulating cooling water, etc., so that the cooling device can obtain an appropriate heat transfer area . Of course, the measuring rod 5 should also be appropriately lengthened under the premise of satisfying the thickness measurement range. In addition, the installation position of the cooling device can be properly adjusted along the axial direction of the measuring rod 5 to meet the needs of the thickness of the pipeline insulation layer 12 .

The cooling device of the present utility model needs to be loaded from the end of the measuring rod 5, so the fitting of the end of the measuring rod 5 and the probe 10 cannot directly adopt the threaded gland to compress the probe (as described in the CN2235603Y document), so Probe positioning block 7 is added. The probe positioning block 7 is fixedly connected with the end of the measuring rod 5 by the countersunk head screw 8, and then the probe pressing block 9 and the spring 11 are used to compress the probe 10.

When the utility model detection device is applied, the material of the measuring rod 5 can be designed to be the same as the material of the measured pipeline 13, and one end of the measuring rod 5 (the bald end without parts such as the probe positioning block 7) is directly welded vertically on the measured pipe 13. On the pipe wall detection point of the pipe 13 to detect the pipe thickness. Ultrasonic testing of the thickness of pipes is known per se.

In order to improve the signal-to-noise ratio of the measuring rod 5, the utility model can spray coating materials on the surface of the measuring rod 5. The cladding material refers to spraying a layer of functional material on the surface of the measuring rod 5 by means of thermal spraying. The cladding material and the material of the measuring rod 5 should have similar acoustic resistance and different sound velocities, such as the carbon steel measuring rod 5 The surface can be sprayed with stainless steel coating.

The design principle of the utility model device is to make the measured object (especially the high temperature and high pressure pipe wall) that is not easy to directly contact produce protrusions, and make the protrusions become a part of the measured object; the thickness (length) of the protrusion is known, and at the same time This protruding part can be cooled again and becomes an easy-to-contact surface. For this reason, the material of the measuring rod 5 designed by the utility model detection device is the same as the measured pipeline material, and is directly welded on the pipe wall detection position of the high temperature and high pressure pipeline 13, and the measuring rod 5 is cooled simultaneously, so the utility model detection device It is possible to use general ultrasonic probes and couplants to better realize, especially, the measurement of the wall thickness of high-temperature and high-pressure pipelines (including on-line detection).

It should also be pointed out that the device and method of the present invention are also feasible when detecting pipelines at normal temperature. At this time, no cooling device is required. In addition, the utility model is also suitable for on-line detection of pipelines where the temperature is not high but the pressure is high and the pipelines are dangerous and difficult to be in close contact with.

When using the detection device of the utility model to detect, it is related to the material selected by the measuring rod 5 , because the propagation speed of the ultrasonic wave depends on the material selected by the measuring rod 5 . When detecting, the material of the measuring rod 5 made by the measuring instrument is calibrated, and after the speed of the ultrasonic wave is determined, the total length (i.e. the total thickness) of the measured object can be directly measured on the measuring instrument.

(High temperature and high pressure) the wall thickness H of pipeline 13 can be calculated by following formula (1):

H=L-h

Wherein, L is the total thickness (length) of the length of the measuring rod 5 and the wall thickness of the measured pipeline 13; h is the length of the measuring rod 5.

Obviously, after subtracting the known length h of the measuring rod 5 from the total length L, what is obtained is the required wall thickness of the measured pipeline 13 .

The unmentioned part of the utility model is applicable to the prior art.

Provide the specific embodiment of the present utility model below, but the utility model is not limited by embodiment.

Example 1

The lower end of the measuring rod 5 is welded on a flat circular plate (simulated pipeline). Both the measuring rod 5 and the circular plate are made of 20 steel. The diameter of the measuring rod 5 is 19 mm, the length is 150 mm, and the surface is sprayed with 1Cr18Ni9Ti stainless steel coating. Coating thickness 0.5mm. After calibration, the selected ultrasonic velocity is 5800 m/s; the thickness of the selected circular plate measured by a precision caliper is 15.7 millimeters, and the measuring rod 5 is welded on the circular plate with the welding rod of the same material. After welding, the upper end surface of the measuring rod to The distance between the upper surface of the circular plate is 151.4mm (including the weld seam of 1.4mm). Fix the probe positioning block 7 with the countersunk head screw 8 at 4-6 mm from the end of the measuring rod 5, place the probe 10 in the central stepped hole 15 of the probe positioning block 7, and fit the upper end of the measuring rod 5. The probe pressing block 9 is fixed on the probe positioning block 7 by threads, and the spring 11 fixed on the probe pressing block 9 presses and fits the probe 10 on the upper end surface of the measuring rod 5 .

The total length L measured by an ultrasonic thickness gauge is 167.2 mm, and the length h of the measuring rod 5 is known to be 151.4 mm. According to the formula (1), it can be known that the thickness of the circular plate (pipe wall thickness) H is 15.8 mm. The error with the original measurement data is only 0.1mm.

Example 2

Based on Example 1, a cooling assembly is installed in the middle of the measuring rod 5; the sleeve 5 is a seamless steel pipe with an outer diameter of 57mm and a wall thickness of 3.5mm, equipped with an end cover 2 and a gland 1, and on the sleeve 5 The water inlet pipe interface 6 and the water outlet pipe interface 6' of the cooling water are set on the wall of the cylinder, and the cooling water circulation system is connected externally, and the cooling length is designed to be 50mm; The water flow rate is 25m ³ /h. At this time, the temperature of the end surface of the measuring rod 5 is measured to be 40°C; in order to calibrate the sound velocity of the system under this temperature environment, the sound velocity is adjusted so that the measured H value is 15.7mm (the rest is the same as in Implementation 1) . Then, another set of testing devices with the same size welded measuring rods but with a circular plate thickness of 19.5 mm is installed with the same water circulation cooling system and heating system. The implementation process and conditions are the same as above, and the measured circular plate thickness is 19.6 mm, which is the same as the original The measurement data also has an error of only 0.1mm.

Claims (3)

1. A detection device for pipeline wall thickness, which comprises a signal acquisition device and an ultrasonic detection system, is characterized in that said signal acquisition device comprises a measuring rod and a ladder-shaped ultrasonic probe, and a probe is fixedly equipped with a screw at one end of the measuring rod Positioning block, the probe positioning block has a probe hole; the large-diameter end of the ultrasonic probe is installed in the probe hole, and fits with the end face of the measuring rod; the probe pressing block is installed on the probe positioning block in a threaded manner, and the probe The pressing block has a central stepped hole, and a spring is installed in it. One end of the spring is installed in the central stepped hole, and the other end is installed on the stepped platform of the ultrasonic probe, and the large diameter end of the probe is pressed and fitted On the contact end face with the measuring rod; the small-diameter end of the ultrasonic probe passes through the spring and protrudes out of the probe pressing block; the other end of the measuring rod is used to be installed on the pipeline to be detected. 2. The detection device for pipe wall thickness according to claim 1, characterized in that the middle part of the measuring rod is covered with a cooling assembly, including a sleeve and matching end caps and glands at its two ends, between the gland and A sealing ring is placed between the end covers, the end cover is welded to the sleeve, and the sealing and axial positioning of the cooling assembly can be realized by tightening the gland; the cooling water inlet pipe interface and outlet pipe interface are set on the wall of the sleeve; the cooling assembly and The external cooling water pipeline circulation system constitutes the cooling device for the measuring rod. 3. The detection device for pipe wall thickness according to claim 1 or 2, characterized in that the measuring rod is a cylinder.

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