JPH0319484B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for measuring deposits on inner walls, and more specifically, the present invention relates to a method for measuring deposits on internal walls, and more specifically, for measuring the state of deposits such as scale attached to the inner walls of various fluid piping and towers and tanks. This invention relates to a method for measuring deposits on inner walls measured from the outside.

[Background technology and its problems] Scale, etc. that adheres to the inner walls of various fluid piping and towers and tanks can cause fluctuations in the flow rate and flow rate of the fluid.
It is necessary to remove this because it obstructs heat transfer and causes corrosion of piping. In order to ensure this removal, it is necessary to accurately detect and measure the state of deposits such as scale.

2. Description of the Related Art Conventionally, a method using radiation is known as a method for detecting the state of scale attached to an inner wall of a fluid pipe or the like. This method uses a radioactive isotope as a radiation source, irradiates the subject with radiation from this source, records the amount of radiation transmitted through the subject as an image on a film, and determines the presence of deposits from the film image. It detects the state.

However, with this method, as shown in Figure 1, the film image appears as a parallel black-and-white density difference, so estimating the state of deposits from such an image does not necessarily accurately grasp the actual situation. It wasn't something I could do. Further, depending on the form of scale adhesion, there were cases in which the difference in black and white density did not appear significantly and the state of the scale could not be determined at all.

[Object of the Invention] An object of the present invention is to accurately measure the thickness of deposits attached to the inner wall of a test object having a substantially circular cross section at each site in the radial direction of the test object, and to
It is an object of the present invention to provide a method for measuring deposits on an inner wall that can be displayed in the most easily visible state.

[Means and effects for solving the problem] Therefore, the present invention provides a method for measuring deposits on an inner wall, which uses radiation to measure the state of deposits attached to the inner wall of a test object having a substantially circular cross section. A source that emits radiation and a sensor that detects the radiation dose from this source as an electrical signal are scanned in the radial direction of the subject with the subject in between, and outputs from the sensor at a plurality of scanning positions are scanned. In addition to measuring the value as a measurement value, the output value from the sensor when no object exists between the radiation source and the sensor is measured as a blank value, and this blank value, the inner diameter of the object, and the object's Based on the coefficients determined mainly by the wall thickness and the material of the object, calculate the theoretical value of the amount of transmitted radiation at each scanning position of the object, assuming that the inside of the object is empty. , After determining the thickness of the deposit at each scanning position of the subject from the theoretical value at each scanning position, each of the above-mentioned measured values, and the specific gravity of the deposit, the thickness of the deposit at each scanning position is determined. This feature is characterized in that the length is divided into two equal parts and displayed on both sides of the corresponding scanning position of a reference circle assuming the inner wall of the subject.

First, the measurement principle of the present invention will be described. Generally, the amount of radiation I that passes through an object decreases depending on the absorption coefficient μ determined by the density of the object and the like, and the thickness x of the object. Now, as shown in FIG. 2, when there is no object between the radiation source 101 that emits radiation and the sensor 102 that detects the radiation from this radiation source 101, the amount of radiation detected by the sensor 102 is blanked. Assuming the value I _B , the amount of transmitted radiation i transmitted through the object 104 with thickness x and absorption coefficient μ is: i=I _B・e ^- 〓

Claims (1)

[Scope of Claims] 1. A method for measuring deposits on an inner wall using radiation, which measures the state of deposits deposited on the inner wall of an object having a substantially circular cross section, which comprises: a radiation source that emits radiation; and a radiation source from this radiation source. A sensor that detects the radiation dose as an electrical signal is scanned in the radial direction of the subject across the subject, and output values from the sensor at a plurality of scanning positions are measured as measurement values, and the line The output value from the sensor when there is no object between the source and the sensor is measured as a blank value, and this blank value is determined based on the inner diameter of the object, the wall thickness of the object, and mainly the material of the object. Based on the coefficients determined by After determining the thickness of the deposit at each scanning position of the subject from the measured value and the specific gravity of the deposit, the thickness of the deposit at each scanning position is divided into two equal lengths. A method for measuring deposits on an inner wall, characterized in that the reference circle is displayed on both sides of the corresponding scanning position on the inside of the reference circle, which is assumed to be the inner wall of a subject.