DD208495A3 - HEAT PROTECTION FOR THE GAMMA RAY DETECTOR OF A TUBE THICKNESS MEASURING DEVICE - Google Patents

Abstract

The invention relates to the protection of a gamma ray detector against heat radiation. The aim of the invention is to protect the gamma ray detector in gamma radiation working wall thickness gauges for heat pipes against damage and destruction, to prevent falsification of the measurement results and to minimize the distance between the object to be measured and the radiation detector. The object is achieved in that the holder of the measuring device receives the gamma ray detector, executed hollow and pierced by water defined pressure, a silicate filter protects the gamma ray detector heat radiation and a double-walled, water-defined pressure flows through Rollgangszwischenstueck at the measuring point encloses the object to be measured.

Description

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Title of the invention

Thermal protection for the gamma ray detector of a tube wall thickness gauge

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Field of application of the invention

The invention relates to the protection of a gamma ray detector in measuring devices against 7 / poor radiation emanating from the object to be measured and is applicable to a device based on the gamma ray absorption device for measuring the wall thickness of warm pipes,

Characteristic of the known technical solutions

Known are working with gamma ray source and gamma ray detectors measuring instruments, in which a cooling of the detector is effected by means of the detector placed around the cooling jacket. In other cases, screw-on cooling plates with meandering cooling water channels are used or cooling coils are placed around the detector. It is also known to compensate for the influence of temperature within certain limits with the aid of electronic circuits,

All these known technical solutions have the rlachteil that the described Ließgeräte at temperatures

to-

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of the material to be measured greater than or equal to 1123 K, as it is a good example in the process of hot rolling of pipes, no longer without the risk of damaging the Gamma3trahlendetek-. and / or falsification of the measurement results can be used * In particular, when in gamma-ray devices for the purpose of reducing the intensity, the gamma ray source small distances "between the warm object to be measured and the gamma ray detector" are necessary, 10

Aim of the invention; .

The object of the invention is to ensure effective protection of the gamma-ray detector against damage and destruction due to thermal radiation in gamma-ray-measuring devices for measuring the wall thickness of pipes heated to 1123 K and higher temperatures, for example during the warm-water process, and to falsification of the gamma ray detector Measurement result by the influence of heat radiation, turn off and to minimize the distance between DUT and gamma ray detector *

presentation; of ^ esQHB the invention;

The technical ^ ^ ^ the ^ by ^

The technical object is to provide for the gamma ray detector,. Preferably Ssintillationssonden or Ionisationslcammem, a Wanddickenmeßgerätes a highly effective heat radiation protection, so that the. V / 'anddickenmeßgerät even when · Temperatures of the measured material greater than or equal to i1 23 K without damage and can be applied without distortion of the measurement result.

Characteristics of invention

Pur the measuring device for determining the thickness of the wall of hot tubes by Cemma ray absorption using a gamma ray source · with a defined intensity, placed on any side of the sample, and a gamma ray detector on the exact opposite side to receive the gamma radiation attenuated by the sample, According to the invention, the protection against thermal loading of the gamma ray detector, in particular a scavenging probe or ionization chamber, on the one hand solved by the supporting and against mechanical damage of the measuring device protective holder receives the gamma ray detector, executed hollow and flows through water defined pressure as a coolant and thereby the gamma ray detector is directly cooled. In addition, according to the invention, the binary flow of the thermal radiation striking the gamma ray detector through the opening in the gamma ray path of the holder is determined by the heat radiation reduced by introducing a silicate filter between heat-radiating tube and gamma ray detector and minimizes the distance between the object to be measured and "gamma ray detector achieved, whereby the intensity of the radioactive source can be kept low *

Furthermore, according to the invention an effective protection of the gamma ray detector against thermal radiation is achieved in that at the measuring location in the technological process of hot rolling of tubes a doppelwandige.s, defined by water pressure roller conveyor intermediate piece is installed, which only at the location of the radiation inlet and outlet a small opening > in order to avoid a causal weakening of the radioactive radiation through the roller table spacer *

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embodiment

Tm. In the following, the invention will be explained in more detail on the basis of a schematic illustration *

The illustration shows a tube 6 lying in a roller conveyor or "moving in the longitudinal direction, which is surrounded at the measuring point by the double-walled, water-carrying roller table piece 5. The roller conveyor piece 5 is formed with an upper and a lower opening.

That the gamma rays emanating from a gamma ray source 7 in the GamnBstrahlengang 4 can pass unattenuated * The gamma radiation passing through the lower opening of the roller table intermediate piece 5 and the thermal radiation emanating from the tube β strike the silicate filter 3 arranged in the gamma ray path 4

The gamma ray detector 2 is inserted into the hollow, water-and-water-run, water-carrying holder 1 and is surrounded by water ·.

Claims (1)

24 123 5 O Invention sanaroruch Thermal protection for the gamma ray detector of a tube wall thickness measuring device, preferably with scintillation probe or ionization chamber as Gannstrahlrahlendetektor, for determining the wall thickness of warm, in quiescent or longitudinal movement befindlicher tubes, wherein the tube temperature can be greater than 1123 K and the distance between the hot tube and radiation detector is minimized characterized characterized in that - the load-bearing support 1, which protects against mechanical damage to the measuring device, receives the gamma ray detector 2, is hollow, and flows through water at a pressure of ΊΟ * to 2 × 10 -4 Ba, a siliceous, heat radiation absorbing and reflecting, for gamma radiation permeable filter 3 is in the gamma ray path 4 before the gamma radiation enters the gamma ray detector 2 and a double-walled, of water at a pressure of 10 ^ to 2 times 10 Pa flows through, with a gamma ray inlet and -a opening provided Rollgangszwischenstück 5 encloses the pipe 6 at the measuring point. For this 1 page drawings