Temperature measuring point sleeve device for high-temperature and high-pressure steam pipeline of thermal power plant

Abstract

The invention discloses a temperature measuring point sleeve device for a high-temperature and high-pressure steam pipeline of a thermal power plant, which is characterized in that a columnar hole and a circular boss with an inclined surface which are communicated with each other are arranged on the side wall of an alloy steel pipeline from outside to inside, and a columnar hole internal thread is arranged on an inner wall of the columnar hole; an alloy steel temperature measuring point sleeve comprises an upper large-diameter cylindrical body, a middle small-diameter cylindrical body and a lower conical body which are connected in sequence; the upper large-diameter columnar body is located on the upper portion of the columnar hole and welded through the same steel fillet weld, the middle small-diameter columnar body is located in the columnar hole, the lower conical body is located in the circular boss with the inclined face, the bottom of the lower conical body extends into the alloy steel pipeline, and external threads are formed in the periphery of the middle small-diameter columnar body; and the top of the alloy steel temperature measuring point sleeve is provided with a temperature measuring element connecting hole. The device is large in rigidity and not prone to vibration, the influence of a weak interface of a dissimilar steel weld joint and the axial pressure of a middle thread of an alloy steel temperature measuring point on an alloy steel pipeline and an alloy steel temperature measuring point sleeve fillet weld is eliminated, and safety and reliability of the sleeve are high.

Description

technical field [0001] The invention relates to the technical field of temperature monitoring of high-temperature and high-pressure steam pipelines in thermal power plants, in particular to a temperature measuring point sleeve device for high-temperature and high-pressure steam pipelines in thermal power plants. [0002] technical background [0003] During the operation of thermal power plant units, in order to accurately reflect the temperature parameters of the working medium (water, steam, etc.), ensure that the temperature of the working medium meets the design requirements, and ensure the safe and stable operation of the unit, it is necessary to design and install several temperature measuring devices on the alloy steel pipes of the thermal power plant. Point device to monitor the working fluid temperature in real time to ensure the safe operation of the unit. [0004] figure 1 Shown is a schematic structural diagram of a traditional temperature measuring point bushing...

AI Technical Summary

Problems solved by technology

The disadvantages and deficiencies of the temperature measuring point bushing are: the austenitic stainless steel temperature measuring point bushing 2 and the alloy steel pipe 1 are austenitic matrix and ferrite matrix respectively, and are connected by dissimilar steels. There is a large difference in chemical composition and thermal expansion coefficient, and the fusion interface between the dissimilar steel weld 3 and the alloy steel pipe 1 is easy to crack; in addition, during the operation of the unit, the austenitic stainless steel temperature measuring point casing 2 is under the action of steam The vibration will form stress concentration at the root of the dissimilar steel weld 3, causing the fusion interface between the dissimilar steel weld 3 and the alloy steel pipe 1 to crack and fall off under the action of alternating stress

The disadvantages and deficiencies of this temperature measuring point casing are: the connection between the stainless steel temperature measuring point casing 3 and the socket 2 also belongs to the welded structure of dissimilar steel, and the chemical composition and thermal expansion coefficient between the two are quite different. The fusion interface between the weld seam 5 and the connecting socket 2 is easy to crack; during the on-site installation process, the stainless steel temperature measuring point sleeve 3 cannot guarantee firm contact with the connecting socket 2, and the stainless steel temperature measuring point sleeve 3 forms a cantilever structure, and the unit is running During the process, vibration will occur under the action of steam, which will cause the upper part of the stainless steel temperature measuring point casing 3 to break, or cause the dissimilar steel weld 5 to crack and leak along the fusion interface with the socket 2, or even fall off, seriously affecting the safety of the unit Stable operation

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