Processing and mounting method of high-temperature acceleration sensor base

Abstract

The application discloses a processing and mounting method of a high-temperature acceleration sensor base, which comprises the following steps: selecting a material same as the material of a rotating machine shell, performing wire cutting on the material, and processing the material into an L*L*T metal base, wherein L>T; performing surface grinding on the metal base; symmetrically processing the lower end of the metal base into two concave spherical surfaces, the lower edges of the two concave spherical surfaces being tangent to each other, and the upper edges of the two concave spherical surfaces being tangent to two edges corresponding to the upper surface of the metal base respectively; milling a cylindrical recess on the upper surface of the metal base; fixing a cylindrical heat-insulating ceramic sintered at high temperature in the cylindrical recess through vacuum brazing, and pre-preparing heat dissipation holes on the side surface of the heat-insulating ceramic; and fixing the processed metal base on the shell through welding. The application enables normal-temperature sensors to be applied to high-temperature components, reduces the use cost of high-temperature special-purpose sensors, and enables vibration signals to be directly transmitted to the acceleration sensor through the welding process filling.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sensor base manufacturing, and particularly relates to a processing and mounting method of a high-temperature acceleration sensor base. BACKGROUND

[0002] At present, in the petrochemical industry, in the aspect of large-scale rotating machinery, vibration parameters are often monitored to avoid unnecessary shutdown, causing production loss and equipment failure.

[0003] When monitoring large-scale rotating machinery, the installation of an acceleration sensor needs to be fixed on the surface of the equipment. The current sensor fixing method usually has hot melt glue fixing and bolt punching. However, the hot melt glue fixing method is not suitable for high-temperature occasions, and the bolt punching method will damage the strength of the structure. SUMMARY

[0004] The application aims to provide a processing and mounting method of a high-temperature acceleration sensor base, which solves the problem that the acceleration sensor cannot be conveniently installed in the high-temperature rotating machinery vibration monitoring process, is reasonable in design, solves the shortcomings of the prior art, and has good effects.

[0005] In order to achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0006] A processing and mounting method of a high-temperature acceleration sensor base, the high-temperature acceleration sensor base is mounted on a rotating machinery shell, and includes the following steps:

[0007] S1, selecting a material same as the material of the rotating machinery shell, linear cutting the material to process an LxLxT metal base, wherein L>T, surface grinding the metal base to control the surface roughness to be less than 0.2 μm;

[0008] S2, symmetrically processing two inner concave spherical surfaces at the lower end of the metal base, the lower edges of the two inner concave spherical surfaces being tangent, and the upper edges of the two inner concave spherical surfaces being tangent to the two edges corresponding to the upper surface of the metal base respectively;

[0009] S3, milling a cylindrical recess on the upper surface of the metal base;

[0010] S4, fixing a cylindrical heat-insulating ceramic sintered at high temperature in the cylindrical recess through vacuum brazing, and pre-preparing heat dissipation holes on the side surface of the heat-insulating ceramic;

[0011] S5, fixing the processed metal base on the shell through welding.

[0012] Further, in S2, first, the lower surface of the metal base is clamped at an angle θ with the vertical direction, and two tangent inner concave spherical surfaces are symmetrically processed through linear cutting with a radius R.

[0013] Further, the calculation formula of θ is as follows:

[0014]

[0015] Wherein, L is the length and width of the upper surface of the metal matrix, and T is the thickness of the metal matrix.

[0016] Further, the calculation formula of R is as follows:

[0017]

[0018] l=T*cosθ.

[0019] Further, in S3, the diameter of the cylindrical groove is greater than the diameter of the heat insulation ceramic.

[0020] Further, in S4, the following steps are included:

[0021] S41, polishing the bottom surface of the cylindrical groove and the lower surface of the heat insulation ceramic to ensure that the roughness R a ≤0.1, flatness ≤0.1;

[0022] S42, pickling and alkaline washing the bottom surface of the cylindrical groove and the lower surface of the heat insulation ceramic to remove oil stains and impurities;

[0023] S43, cutting the nickel-based filler metal BNi-2 strip and placing it between the bottom surface of the cylindrical groove and the lower surface of the heat insulation ceramic;

[0024] S44, placing the metal matrix, filler metal and heat insulation ceramic in a vacuum brazing furnace for brazing, the vacuum degree is pre-adjusted to 0.05 Pa or filled with 99.99% nitrogen, rapidly heated to make the brazing temperature reach 1050℃, and after a period of time, the filler metal is fully melted and capillary adsorbed on the bottom surface of the cylindrical groove and the lower surface of the heat insulation ceramic;

[0025] S45, finally adopt the way of cooling with the furnace.

[0026] Further, in S4, the side surface of the heat insulation ceramic is provided with four groups of heat dissipation hole groups, the first group and the third group of heat dissipation hole groups are opposite, each including 3 heat dissipation holes, and the 3 heat dissipation holes are arranged in a row; the second group and the fourth group of heat dissipation hole groups are opposite, each including 6 heat dissipation holes, 3 in a row, and arranged in two rows.

[0027] Further, S5 includes the following steps:

[0028] S51, selecting the middle points on the two opposite straight edges of the lower surface of the metal matrix for spot welding and fixing, and then welding the metal filling;

[0029] S52, with the tangent point between the two inner concave spherical surfaces as a demarcation point, the lower edges of the two inner concave spherical surfaces are divided into four weld seam paths, the weld seam paths are welded first, then metal filling is carried out, the welding and metal filling are both started from the tangent point, and the welding direction is from inside to outside and the welding sequence is symmetrical welding.

[0030] Further, a large current is used when welding the first weld seam path, and the welding current is 180A-200A, and the welding current is reduced when welding the other three weld seam paths.

[0031] Further, the welding method of the weld seam path adopts manual arc welding.

[0032] The beneficial technical effects brought by the present application are:

[0033] The present application increases the ceramic part by brazing, so that the normal temperature sensor can be applied to high temperature parts, and the use cost of the high temperature special sensor is reduced; through the welding process filling, on the basis of avoiding thermal deformation, the vibration signal can be directly transmitted to the acceleration sensor. BRIEF DESCRIPTION OF DRAWINGS

[0034] The present application will be further described below in conjunction with the drawings:

[0035] Figure 1 It is a front view of the metal base in one embodiment of the present application;

[0036] Figure 2 It is a left view of the metal base in one embodiment of the present application;

[0037] Figure 3 It is a top view of the metal base in one embodiment of the present application;

[0038] Figure 4 It is a schematic view of the metal base in one embodiment of the present application;

[0039] Figure 5 It is a front view of the heat insulation ceramic in one embodiment of the present application;

[0040] Figure 6 It is a left view of the heat insulation ceramic in one embodiment of the present application;

[0041] Figure 7 It is a top view of the heat insulation ceramic in one embodiment of the present application;

[0042] Figure 8 It is a schematic view of the heat insulation ceramic in one embodiment of the present application;

[0043] Figure 9 It is a schematic view of the high temperature acceleration sensor base structure in one embodiment of the present application;

[0044] Wherein, 1-metal base; 2-inner concave spherical surface; 3-cylindrical groove; 4-cylindrical groove bottom surface; 5-metal base upper surface; 6-metal base lower surface; 7-first spot welding fixing point; 8-second spot welding fixing point; 9-first welding seam path; 10-fourth welding seam path; 11-second welding seam path; 12-third welding seam path; 13-heat insulation ceramic; 14-heat insulation ceramic upper surface; 15-heat insulation ceramic lower surface; 16-radiating hole; DETAILED DESCRIPTION

[0045] The application proposes a processing and mounting method of a high-temperature acceleration sensor base.

[0046] Taking the vibration monitoring of flue gas rotating rotor blades in the catalytic cracking process of a refining enterprise as an example, the temperature of the flue gas machine casing is about 300 DEG C, and an acceleration sensor is installed at the transition ring position of the flue gas machine, and the structure of the acceleration sensor base is as shown in Figures 1 to 9 The processing and mounting method of the base is as follows:

[0047] S1, selecting the same material (high-temperature alloy GH864) as the rotating machine shell to avoid galvanic corrosion or large residual stress caused by dissimilar steel welding, and performing linear cutting to process an LxLxT metal base 1, L is the length and width of the metal base upper surface 5, L is 50 mm, T is the thickness of the metal base 1, T is 20 mm, and the surface of the metal base 1 is ground to control the surface roughness to be less than 0.2 μm;

[0048] S2, the lower end of the metal base 1 is symmetrically processed into two inner concave spherical surfaces 2, the lower edges of the two inner concave spherical surfaces 2 are tangent, and the upper edges of the two inner concave spherical surfaces 2 are respectively tangent to the two edges corresponding to the metal base upper surface 5.

[0049] Specifically, first, the metal base lower surface 6 is clamped at an angle θ with the vertical direction, and linear cutting is performed with a radius R to symmetrically process two tangent inner concave spherical surfaces 2.

[0050] The calculation formula of θ is as follows:

[0051]

[0052] The calculation formula of R is as follows:

[0053]

[0054] l=T*cosθ=15.6;

[0055] S3, milling a cylindrical groove 3 on the upper surface 5 of the metal base, the depth t of the cylindrical groove 3 is 5mm, the diameter D of the cylindrical groove 3 is 32mm, the diameter d of the heat insulation ceramic 13 is 30mm, leaving a gap to avoid thermal stress between the heat insulation ceramic 13 and the metal base 1 due to the uneven thermal expansion coefficient, and facilitating heat dissipation of the heat insulation ceramic 13;

[0056] S4, the cylindrical heat insulation ceramic 13 fired at high temperature is fixed in the cylindrical groove 3 by vacuum brazing to play a heat insulation role; S4 specifically includes the following steps:

[0057] S41, grinding the bottom surface 4 of the cylindrical groove and the lower surface 15 of the heat insulation ceramic to ensure that the roughness Ra is less than or equal to 0.1, and the flatness ≤0.1;

[0058] S42, pickling and alkali washing the bottom surface 4 of the cylindrical groove and the lower surface 15 of the heat insulation ceramic to remove oil stains and impurities;

[0059] S43, cutting the nickel-based filler material BNi-2 strip with a thickness of 120μm and placing it between the bottom surface 4 of the cylindrical groove and the lower surface 15 of the heat insulation ceramic;

[0060] S44, placing the metal base 1, the filler material and the heat insulation ceramic 13 in the vacuum brazing furnace for brazing, pre-achieving a vacuum degree of 0.05Pa or filling 99.99% nitrogen, rapidly heating to make the brazing temperature reach 1050℃, maintaining for a period of time (about 30 minutes) to make the filler material fully melt and capillary adsorb the bottom surface 4 of the cylindrical groove and the lower surface 15 of the heat insulation ceramic;

[0061] S45, finally adopting the way of furnace cooling to avoid too fast cooling causing cracking between the heat insulation ceramic 13 and the metal base 1.

[0062] The side surface of the heat insulation ceramic 13 is provided with four groups of heat dissipation hole groups, the first group and the third group of heat dissipation hole groups are opposite and each includes three heat dissipation holes 16 arranged in a row; the second group and the fourth group of heat dissipation hole groups are opposite and each includes six heat dissipation holes 15 arranged in two rows with three in a row. The radius r of the heat dissipation hole 16 is 1.5mm, the horizontal interval a between the heat dissipation holes 16 is 7.5mm, the interval between the centers of the adjacent two rows of heat dissipation holes 16 along the vertical direction is 3r, i.e. 4.5mm, and the upper row of heat dissipation holes 16 and the lower row of heat dissipation holes 16 in the second group and the fourth group of heat dissipation holes 16 are respectively 1.5mm away from the upper surface 14 and the lower surface of the heat insulation ceramic 1.5mm;

[0063] S5, fixing the processed metal base 1 on the shell by welding;

[0064] Specifically, S5 includes the following steps:

[0065] S51. Select the midpoints on the two opposite sides of the lower surface of the metal substrate for spot welding and fixation, namely the first spot welding fixation point 7 and the second spot welding fixation point 8, and then fill the metal with welding.

[0066] S52. Taking the tangent point between the two concave spherical surfaces 2 as the dividing point, the lower edge of one of the concave spherical surfaces 2 is divided into the first weld path 9 and the second weld path 11, and the lower edge of the other concave spherical surface 2 is divided into the third weld path 12 and the fourth weld path 10. First, the weld path is welded for the root pass, and then it is filled with metal. Both the root pass and the metal filling are started from the tangent point. The welding method of manual arc welding, the welding direction from the inside to the outside and the symmetrical welding sequence are adopted to avoid excessive local deformation.

[0067] Specifically, the first weld path 9 and the third weld path 12 are located on the same side, and the second weld path 11 and the fourth weld path 10 are located on the same side. The first weld path 9, the fourth weld path 10, the second weld path 11, and the third weld path 12 are welded sequentially using a symmetrical welding sequence. The welding rod diameter is 4mm. A larger welding current (180-200A) is used when welding the first weld path 9 to avoid incomplete penetration, allowing the accelerometer to directly and accurately capture the weak characteristic signals of mechanical vibration. When welding the other three weld paths, the welding current is reduced to ensure weld quality.

[0068] The accelerometer is mounted on the base, and the temperature field distribution of the accelerometer is calculated:

[0069] Finite element calculation: (1) Finite element modeling: SolidWorks was used to model the accelerometer base at a 1:1 scale, and then the model was imported into ABAQUS for analysis; (2) Material property definition: The specific heat of the thermal insulation ceramic is 750 J / kg / ℃, the thermal conductivity is 0.5 W / m / ℃, and the density is 2.9 g / mm³. 3 The specific heat of the metallic matrix is ​​500 J / kg / ℃, the thermal conductivity is 20 W / m / ℃, and the density is 7.8 g / mm³. 3 (3) Boundary condition setting: Since the flue gas turbine is installed outdoors and in direct contact with the air, the forced convection coefficient is defined as 0.1 Mw / mm. 2 / ℃, the lower part of the metal substrate is in contact with the transition liner of the flue gas turbine, and the temperature is defined as 300℃; (4) Analysis step and mesh generation: Heat Transfer analysis step is adopted, steady state analysis; the mesh adopts DC3D4 element type; (5) Result output: the overall temperature field distribution of the accelerometer base is output in the result file, TEMP.

[0070] After the temperature field reaches stability, according to the temperature field distribution result of the acceleration sensor base output by the result file, it can be seen that the temperature gradually decreases along the bottom of the base, the temperature gradient is large at the contact part of the heat insulation ceramic and the metal base, rapidly decreases to 27.89 DEG C, close to the room temperature level, and meets the use requirements of the conventional sensor long-term installation and offline fixed-point test environment.

[0071] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the essential scope of the present application should also belong to the protection scope of the present application.

Claims

1. A method for processing and installing a high-temperature accelerometer base, wherein the high-temperature accelerometer base is installed on a rotating machinery housing, characterized in that, Includes the following steps: S1. Select a material with the same material as the rotating machinery shell, and wire cut it to form a metal substrate of size L×L×T, where L is the length and width of the upper surface of the metal substrate, and T is the thickness of the metal substrate, where L>T. Grind the surface of the metal substrate to control the surface roughness to be less than 0.2μm. S2. Two concave spherical surfaces are symmetrically machined at the lower end of the metal substrate. The lower edges of the two concave spherical surfaces are tangent to each other, and the upper edges of the two concave spherical surfaces are tangent to the two corresponding sides of the upper surface of the metal substrate. S3. A cylindrical groove is milled on the upper surface of the metal substrate; the upper surface of the metal substrate refers to the surface with a side length of L×L, and the lower end of the metal substrate refers to the lower surface, which is the surface opposite to the upper surface; S4. The cylindrical heat-insulating ceramic, which is fired at high temperature, is fixed in the cylindrical groove by vacuum brazing, and heat dissipation holes are pre-made on the side surface of the heat-insulating ceramic. S5. Fix the processed metal substrate onto the shell by welding; S5 includes the following steps: S51. Select the midpoints on the two opposite straight edges of the lower surface of the metal substrate for spot welding and fixation, and then fill with welded metal. S52. Using the tangent point between the two concave spherical surfaces as the dividing point, the lower edges of the two concave spherical surfaces are divided into four weld paths. First, the weld paths are welded for the root pass, and then the metal is filled. Both the root pass and the metal filling are started from the tangent point, and the welding direction and welding sequence are from the inside to the outside and symmetrical welding.

2. The processing and installation method of a high-temperature accelerometer base according to claim 1, characterized in that, In step S2, the lower surface of the metal substrate is first clamped at an angle θ to the vertical direction, and then wire-cut with radius R to symmetrically process two tangent concave spherical surfaces.

3. The processing and installation method of a high-temperature accelerometer base according to claim 2, characterized in that, The formula for calculating θ is as follows: Where L is the length and width of the upper surface of the metal substrate, and T is the thickness of the metal substrate.

4. The processing and installation method of a high-temperature accelerometer base according to claim 3, characterized in that, The formula for calculating R is as follows: l = T·cosθ.

5. The processing and installation method of a high-temperature accelerometer base according to claim 1, characterized in that, In S3, the diameter of the cylindrical groove is larger than the diameter of the heat-insulating ceramic.

6. The processing and installation method of a high-temperature accelerometer base according to claim 1, characterized in that, The S4 process includes the following steps: S41. Grind the bottom surface of the cylindrical groove and the lower surface of the heat-insulating ceramic to ensure a surface roughness R. a ≤0.1, flatness ≤0.1; S42. Perform acid and alkali washing on the bottom surface of the cylindrical groove and the lower surface of the heat insulation ceramic to remove oil and impurities; S43. Cut the nickel-based brazing filler metal BNi-2 strip and place it between the bottom of the cylindrical groove and the lower surface of the heat-insulating ceramic. S44. Place the metal substrate, brazing filler metal and heat insulation ceramic in a vacuum brazing furnace for brazing. The vacuum degree is pre-set to 0.05 Pa or filled with 99.99% nitrogen. The temperature is rapidly increased to 1050℃. After holding for a period of time, the brazing filler metal is fully melted and capillary adsorption occurs on the bottom surface of the cylindrical groove and the lower surface of the heat insulation ceramic. S45. Finally, cooling is carried out by furnace cooling.

7. The processing and installation method of a high-temperature accelerometer base according to claim 1, characterized in that, The side surface of the heat-insulating ceramic is provided with four sets of heat dissipation holes. The first and third sets of heat dissipation holes are opposite each other and each includes 3 heat dissipation holes, which are arranged in a row. The second and fourth sets of heat dissipation holes are opposite each other and each includes 6 heat dissipation holes, which are arranged in two rows of 3.

8. The processing and installation method of a high-temperature accelerometer base according to claim 7, characterized in that, When welding the first weld path, the welding current is 180A-200A. When welding the other three weld paths, the welding current is reduced.

9. The processing and installation method of a high-temperature accelerometer base according to claim 8, characterized in that, The welding method for the weld seam path is manual arc welding.

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