A thickness detection device for a butterfly gasket on a nuclear fuel assembly

Abstract

The present invention belongs to the technology of nuclear fuel assembly manufacturing, and particularly relates to a thickness detection device for a butterfly gasket on a nuclear fuel assembly. A thickness detection device for a butterfly gasket on a nuclear fuel assembly includes a micrometer. The micrometer is disposed above a fixed base. A positioning ring and a probe fixing base are installed in a positioning base. A vertical probe is provided on the probe fixing base. The positioning ring is fixedly connected to the lower end of the micrometer. With the disc washer fixing base as the main body, a lower-end relief cylinder and a positioning hexagonal washer are provided. The upper end is connected to a detection meter by a fixing member. The detection probe is connected to the probe fixing base and then connected to the detection meter. Elastic two-probe two-point detection is used to achieve the thickness detection of the gasket. When designing the disc gasket detector, considering the accuracy, a two-point needle detection with a smaller contact surface and more accurate detection is adopted. The designs of the positioning base and the probe fixing base take into account the deformation and scratching of the detected product caused by their weight and appearance.

Description

Technical Field

[0001] The invention belongs to the technology of nuclear fuel assembly manufacturing, and particularly relates to a thickness detection device for a butterfly gasket on a nuclear fuel assembly. Background Art

[0002] Under the compression nut of the water rod on the fuel assembly is a butterfly gasket, and at the periphery of the nut is the upper end plug of the fuel rod. After assembly, it is necessary to detect the thickness of the butterfly gasket to ensure that the thickness of the butterfly gasket after locking is within the range required by the technical conditions.

[0003] For conventional gaskets, inspectors usually use tools such as vernier calipers and micrometers for manual measurement. However, due to the special structure of the nuclear fuel assembly, specifically as Figure 1 Since the detection tolerance is 0.02 mm, the detection accuracy of the inspection tools used should be better than 0.005 mm. Conventional measuring instruments cannot perform accurate measurement, and the measurement error is often large. It is necessary to design a special device for measurement. Summary of the Invention

[0004] The purpose of the invention is to provide a thickness detection device for a butterfly gasket on a nuclear fuel assembly, which can accurately measure the thickness of the butterfly gasket on the nuclear fuel assembly.

[0005] The technical solution of the invention is as follows:

[0006] A thickness detection device for a butterfly gasket on a nuclear fuel assembly includes a dial indicator. The dial indicator is arranged above a fixed base. A positioning ring and a probe fixing seat are arranged inside the positioning base. A vertical probe is arranged on the probe fixing seat, and the positioning ring is fixedly connected to the lower end of the dial indicator.

[0007] The positioning base is in the shape of a wine glass, with the large end at the top and the small end at the bottom, and a smooth conical surface is used for transition between the large end and the small end.

[0008] A through hole is machined at the center of the positioning base. The upper end of the through hole is a counterbore with a larger diameter, the middle section is a smooth cylindrical hole, and the lower end is a hexagonal hole.

[0009] The positioning ring is installed in the counterbore at the upper end of the through hole.

[0010] The probe fixing seat is installed in the smooth cylindrical hole in the middle section, and vertical probes are uniformly distributed along the axial direction on the probe fixing seat.

[0011] The lower end of the probe extends out of the probe fixing seat and penetrates into the hexagonal hole at the small end of the positioning base.

[0012] Openings corresponding in position are machined on the small end of the positioning base, and the opening positions correspond to the positions of the lower ends of the probes.

[0013] The ratio of the height of the large end to the height of the small end of the positioning base is 1.5 to 1, the ratio of the height of the tapered section to the height of the small end is 1:3 to 1:1, and the angle of the tapered surface transition is 30 to 50°.

[0014] The depth of the upper counterbore of the through hole at the center of the positioning base accounts for 1:3 to 1:2 of the height of the entire large end part, and the height of the lower hexagonal hole accounts for 1:3 to 2:3 of the height of the entire small end part.

[0015] The positioning ring locks and fixes the dial indicator with a locking screw, and the positioning base fixes the positioning ring with a locking screw.

[0016] The remarkable effects of the present invention are as follows: The thickness detector for the disc gasket takes the disc washer fixing seat as the main body, with an avoidance cylinder at the lower end, a positioning hexagonal washer, a detection table connected by a fixing member at the upper end, a detection needle connected to the detection needle fixing seat and then connected to the detection table. Elastic two-needle two-point detection is used to realize the detection of the gasket thickness. When designing the disc gasket detector, considering the accuracy, a two-point needle detection with a smaller contact surface and more accurate detection is adopted. The designs of the positioning base and the detection needle fixing seat take into account their weight and appearance to avoid deformation and scratching of the detected products. The positioning base adopts a tapered surface transition design for the large end and the small end, and the lower end is not designed as a cylindrical shape in the original state, taking into account the positioning hexagonal washer, which can not only fix the detection instrument but also reliably install the probe. It meets the installation environment of the depth detection instrument with a retractable structure, and the detection accuracy can be guaranteed, meeting the technical requirements for the detection of disc gaskets. Description of the Drawings

[0017] Figure 1 It is a device for detecting the thickness of the butterfly gasket on the nuclear fuel assembly;

[0018] Figure 2 It is a schematic diagram of the positioning base;

[0019] Figure 3 It is a schematic diagram of the detection needle fixing seat;

[0020] In the figure: 1. Dial indicator; 2. Positioning base; 3. Positioning ring; 4. Detection needle fixing seat; 5. Detection needle; 6. Locking screw; 7. Dial indicator locking screw. Detailed Embodiments

[0021] The present invention will be further described below with reference to the drawings and specific embodiments.

[0022] As Figure 1 shown, the dial indicator 1 is installed above the positioning base 2, and the positioning ring 3 and the detection needle fixing seat 4 are installed inside the positioning base 2. The vertical detection needle 5 is installed on the detection needle fixing seat 4. The lower end of the above-mentioned dial indicator 1 is locked and fixed by the dial indicator locking screw 7 installed inside the positioning ring 3. At the same time, the above-mentioned positioning ring 3 is fixed by the locking screw 6.

[0023] As shown Figure 2 in the figure, the outer shape of the positioning base 2 is wine glass-shaped, with the large end at the top and the small end at the bottom. A smooth conical surface is used for the transition between the large end and the small end. The ratio of the height of the large end to the height of the small end is 1.5 to 1. The ratio of the height of the conical section to the height of the small end is 1:3 to 1:1.

[0024] A through hole is machined at the center of the positioning base 2. The upper end of the through hole is a counterbore with a larger diameter, the middle section is a smooth cylindrical hole, and the lower end is a hexagonal hole.

[0025] The angle of the conical surface transition is 30 to 50°, preferably 45°.

[0026] The depth of the counterbore at the upper end of the through hole accounts for 1:3 to 1:2 of the height of the entire large end part.

[0027] The height of the hexagonal hole at the lower end accounts for 1:3 to 2:3 of the height of the entire small end part.

[0028] During installation, the above-mentioned positioning ring 3 is installed in the counterbore at the upper end of the through hole, and the positioning ring 3 and the lower part of the dial indicator 1 are fixed by a locking screw.

[0029] The above-mentioned probe fixing seat 4 is installed in the smooth cylindrical hole in the middle section. Vertical probes 5 are evenly distributed along the axial direction on the probe fixing seat 4. At the same time, openings corresponding to the positions are machined on the small end of the positioning base 2 for observing the probes 5 to facilitate observing the state during detection.

[0030] The function of the hexagonal hole is to enable the positioning base 2 to fit tightly with the corresponding installed locking nut for reliable positioning.

[0031] The positioning base 2 adopts the conical surface transition design of the large end and the small end, and the lower end is not designed as a cylindrical shape in the original state. Considering the positioning hexagonal washer, it can not only fix the detection instrument but also reliably install the probe. It meets the installation environment of the retractable structure depth detection instrument, and the detection accuracy can be guaranteed, meeting the technical requirements for the detection of disc gaskets.

[0032] As shown Figure 3 in the schematic diagram of the probe fixing seat 4, an installation column with an external thread is machined at its upper end, and the installation column is threadedly connected to the lower end of the dial indicator 1. Vertical installation holes are machined in the circumferential direction of the probe fixing seat 4 for installing the probes 5.

[0033] The entire probe fixing seat 4 is installed in the smooth cylindrical hole in the middle section of the through hole of the positioning base 2. The lower end of the probe 5 extends out of the fixing seat 4 and penetrates into the hexagonal hole at the small end of the positioning base 2, and the probe 5 is observed through the observation port at the small end of the positioning base 2.

Claims

1. A thickness detection device for a butterfly gasket on a nuclear fuel assembly, comprising a micrometer (1), characterized in that: The dial indicator (1) is arranged above the positioning base (2). A positioning ring (3) and a probe fixing seat (4) are installed in the positioning base (2). A vertical probe (5) is provided on the probe fixing seat (4). The positioning ring (3) is fixedly connected to the lower end of the dial indicator (1). The positioning base (2) is in the shape of a wine glass, with the larger end at the top and the smaller end at the bottom, and a smooth conical surface is used for transition between the larger end and the smaller end. A through hole is machined at the center of the positioning base (2). The upper end of the through hole is a counterbore with a larger diameter, the middle section is a smooth cylindrical hole, and the lower end is a hexagonal hole. The probe fixing seat (4) is installed in the smooth cylindrical hole in the middle section, and vertical probes (5) are installed vertically and evenly distributed along the axial direction on the probe fixing seat (4). The lower end of the probe (5) extends out of the probe fixing seat (4) and penetrates into the hexagonal hole at the smaller end of the positioning base (2). Openings corresponding in position are machined at the smaller end of the positioning base (2), and the opening positions correspond to the positions of the lower ends of the probes (5).

2. The thickness detection device for the butterfly gasket on a nuclear fuel assembly according to claim 1, wherein: The positioning ring (3) is installed in the counterbore at the upper end of the through hole.

3. A thickness detection device for a butterfly gasket on a nuclear fuel assembly according to claim 1, characterized in that: The ratio of the height of the larger end to the height of the smaller end of the positioning base (2) is 1.5 - 1. The ratio of the height of the conical section to the height of the smaller end is 1:3 - 1:1, and the angle of the conical surface transition is 30 - 50°.

4. The thickness detection device for the butterfly gasket on a nuclear fuel assembly according to claim 1, characterized in that: The depth of the counterbore at the upper end of the through hole at the center of the positioning base (2) accounts for 1:3 - 1:2 of the height of the entire larger end part, and the height of the lower hexagonal hole accounts for 1:3 - 2:3 of the height of the entire smaller end part.

5. The thickness detection device for the butterfly gasket on a nuclear fuel assembly according to claim 1, characterized in that: The positioning ring (3) locks and fixes the dial indicator (1) through a locking screw (7), and the positioning base (2) fixes the positioning ring (3) through a locking screw (6).

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