Pressure stabilizer manhole cover plate centering device and method

Abstract

The invention provides a pressure stabilizer manhole cover plate centering device which is characterized in that the pressure stabilizer manhole cover plate centering device comprises an eccentric rod, the eccentric rod is provided with a lower cylinder and an upper cylinder, the lower cylinder is sleeved with a screw sleeve, the upper cylinder is sleeved with a screw hole sleeve, and an executing mechanism is arranged below the eccentric rod and used for achieving the rotating action. The invention further provides a centering method for the manhole cover plate of the voltage stabilizer. The centering method comprises hole opening operation and hole closing operation. The device is convenient for personnel to operate, does not need additional tools, is made of an easy-to-decontaminate material, and avoids radioactive surface contamination.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear power unit voltage regulators, and in particular to a voltage regulator manhole cover centering device and method. Background Art

[0002] In the Hualong One nuclear power unit, the pressurizer is a key device in the primary circuit. During operation, it controls the pressure and protects against overpressure in the primary circuit, and is the pressure boundary of the primary circuit. Opening and closing the manhole during overhaul is a key operation for the state transition of the nuclear power unit.

[0003] The manhole of the voltage regulator is connected by bolt flange, and the center line of the cover plate is 45 degrees to the position of the voltage regulator body. Since the cover plate is heavy, about 350Kg, it is easy to misalign the cover plate and the manhole pipe seat of the voltage regulator during installation. If misaligned, it may: 1. The bolts cannot be screwed in / out; 2. The bolt / screw thread is damaged; which in turn affects the sealing function of the voltage regulator and causes leakage of radioactive media.

[0004] The original design tool was a simple three-claw sling. During the centering process, a crowbar was used to center the cover. This method has low centering accuracy, slow speed, and is easy to damage the thread of the bottom hole of the stabilizer bolt. After an improved design, a clamp-type centering tool and steps were added, but there are still the following shortcomings: First, the tool is heavy and requires 2-3 people to install. Second, after placing the cover in the device, the position needs to be adjusted several times to align the center axis of the manhole cover with the device. Third, the circumferential direction cannot be accurately centered and still needs to be centered in the circumferential direction by using a crowbar or sling.

[0005] The manhole of the Hualong One nuclear power unit has a smaller space and a higher radiation dose, which is not suitable for workers to stay for a long time. It is necessary to design a simple and easy-to-operate manhole cover centering device to reduce the difficulty of centering adjustment of the manhole cover, improve maintenance efficiency, reduce the radiation dose of personnel, and ensure the normal operation of the equipment. Summary of the invention

[0006] The purpose of the present invention is to provide a centering device and method for a manhole cover of a voltage stabilizer, which solves the problems of too many operators involved in the existing centering, multiple adjustments required, and the inability to accurately achieve centering in the circumferential direction.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A centering device for a manhole cover of a voltage stabilizer is characterized in that it includes an eccentric rod, the eccentric rod has a lower cylinder and an upper cylinder, the lower cylinder is sleeved with a screw sleeve, the upper cylinder is sleeved with a screw hole sleeve, and an actuator is provided below the eccentric rod to realize a rotational action.

[0009] As an practicable manner, the screw sleeve and the screw hole sleeve are fixed by a fixing nut installed on the top of the upper cylinder.

[0010] As an implementable manner, a threaded hole is provided on the top of the upper cylinder, and the fixing nut is fixed in cooperation with the threaded hole by a fixing screw.

[0011] As an implementable manner, the screw sleeve and the lower cylinder are clearance-fitted.

[0012] As an implementable manner, the screw hole sleeve and the upper cylinder are clearance-fitted.

[0013] As an implementable manner, the eccentric rod has an operating mechanism, and the operating mechanism includes a hexagonal column with an operating hole and a hexagonal column without a hole.

[0014] As an implementable manner, the outer diameter of the upper cylinder is 30.8 mm, the outer diameter of the lower cylinder is 39 mm, and the eccentric distance between the upper cylinder and the lower cylinder is 2.7 mm.

[0015] As an implementable manner, the thickness of the screw sleeve and the screw hole sleeve are both 5.5 mm, the outer diameter of the screw hole sleeve is 42.4 mm, and the outer diameter of the screw sleeve is 50 mm.

[0016] As an practicable manner, the material of the screw sleeve and the screw hole sleeve is polytetrafluoroethylene, and the material of the eccentric rod is stainless steel.

[0017] A method for centering a manhole cover plate of a voltage stabilizer comprises the following steps:

[0018] Step 1: Fix the position of the manhole cover plate with a sling or adjust the position to ensure that at least one of the 16 main bolts of the voltage stabilizer is screwed out smoothly, insert the centering device of the manhole cover plate of the voltage stabilizer into the bolt hole, and make the threaded part contact with the screw hole sleeve, and the screw sleeve contact with the manhole cover plate;

[0019] Step 2: Use an S30 wrench to rotate or a φ12 lever to rotate the actuator, forming a support point with the upper part of the eccentric rod and the screw hole sleeve. During the rotation, the manhole cover of the voltage stabilizer is forced to move. Observe whether the light hole of the manhole cover is concentric with the flange screw hole until the holes are concentric. At this time, the adjacent bolts can be screwed out smoothly;

[0020] Step 4: After unscrewing some of the bolts, if some of the bolts cannot be unscrewed, use another stabilizer manhole cover centering device to insert it into another hole, so that the stabilizer manhole cover is circumferentially centered, so that all the main bolts can be unscrewed smoothly;

[0021] Step 5: After removing the remaining main bolts, remove the centering device of the manhole cover of the voltage stabilizer.

[0022] Compared with the prior art, the centering device and method for the manhole cover of a pressurizer provided by the present invention have the following advantages:

[0023] Beneficial effects:

[0024] The operating torque of the centering operation of the present invention is no more than 150 N.m, which is convenient for personnel to operate.

[0025] Furthermore, the device of the present invention weighs 3.5 kg, which is convenient for one person to transport, carry and install with one hand.

[0026] Furthermore, the operating tool of the device is consistent with the operating tool of the main bolt / main nut of the voltage stabilizer, and no additional tools are required.

[0027] Furthermore, the device is made of easily decontaminated materials to avoid radioactive surface contamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for the technical description.

[0029] Figure 1 An exploded view of the centering device for the manhole cover of a pressurizer provided by the present invention;

[0030] Figure 2 for Figure 1 A cross-sectional view of

[0031] Figure 3 An assembly diagram of the centering device for the manhole cover of a voltage stabilizer provided by the present invention;

[0032] Figure 4 for Figure 3 A cross-sectional view of

[0033] Figure 5 This is a schematic diagram of the operation of the centering tool provided by the present invention.

[0034] Description of reference numerals:

[0035] 1. Eccentric rod; 2. Screw sleeve; 3. Screw hole sleeve; 4. Fixing nut; 5. Fixing screw; 6. Actuator. DETAILED DESCRIPTION

[0036] The following is further explained in detail through specific implementation methods.

[0037] like Figures 1 to 4As shown, the present invention provides a centering device for a manhole cover of a voltage stabilizer, comprising an eccentric rod 1, a screw sleeve 2, a screw hole sleeve 3, a fixing nut 4, and a fixing screw 5. The eccentric rod 1 has an actuator 6, and the actuator 6 has an operating hole and an external hexagonal head. The function of the actuator 6 is: since the centers of the screw sleeve 2 and the screw hole sleeve 3 are not in a straight line, after the device is installed, it needs to be rotated. During the rotation, since the screw sleeve 2 and the screw hole sleeve 3 are not concentric, the manhole cover can be operated to adjust the position and realize centering; through the operation of the actuator 6, the rotation action can be realized.

[0038] The cylindrical part of the eccentric rod 1 is assembled with the screw sleeve 2 and the screw hole sleeve 3 respectively, and fixed by the fixing nut 4 and the fixing screw 5. The actuator 6 and the eccentric rod 1 are processed as a whole or connected by welding. The centering device can fine-tune the position of the manhole cover plate, and quickly and accurately adjust the bolt hole on the manhole cover plate to the center position of the bolt hole on the manhole seat. The screw hole sleeve 3 (the upper part of the eccentric rod), the screw sleeve 2 (the lower part of the eccentric rod), the fixing nut 4, the fixing screw 5, and the actuator 6 are all connected to the eccentric rod 1. Except for the fixing screw 5, all are clearance fits.

[0039] Specifically, the eccentric rod 1 is composed of two cylinders and an operating mechanism (actuator 6). The two cylinders are composed of a larger cylinder at the bottom and a smaller cylinder at the top.

[0040] Preferably, the outer diameter of the cylinder at the upper part of the eccentric rod 1 is 30.8 mm, the outer diameter of the cylinder at the lower part is 39 mm, and the eccentric distance between the two cylinders is 2.7 mm. An M10 screw hole is provided on one side, and the screw hole sleeve 3 (the upper part of the eccentric rod) and the screw sleeve 2 (the lower part of the eccentric rod) are fixed on the eccentric rod 1 by means of a fixing screw 5 and a fixing thread.

[0041] Preferably, the eccentric rod 1 is made of stainless steel.

[0042] Preferably, the operating mechanism (actuator 6) of the eccentric rod 1 includes two parts: a hexagonal column with an operating hole (φ13) (distance between opposite sides 45 mm) and a hexagonal column without a hole (distance between opposite sides 30 mm). The dimensions are consistent with the operating tools of the main bolt / main nut of the voltage stabilizer, reducing the number of tools in the maintenance process and facilitating operation in narrow spaces and high-dose conditions.

[0043] The screw sleeve 2 is sleeved on the cylinder at the bottom of the eccentric rod 1 with a clearance fit; the screw hole sleeve 3 is sleeved on the cylinder at the top of the eccentric rod 1 with a clearance fit, and the fixing nut 4 is installed on the upper cylinder and is tightened by the fixing screw 5 to fix the screw sleeve 2 and the screw hole sleeve 3.

[0044] Preferably, the thickness of the screw hole sleeve 3 (the upper part of the eccentric rod) and the screw sleeve 2 (the lower part of the eccentric rod) are both 5.5 mm, the outer diameter of the screw hole sleeve 3 is 42.4 mm, and the outer diameter of the screw sleeve 2 is 50 mm.

[0045] Preferably, the material of the screw sleeve 2 and the screw hole sleeve 3 is polytetrafluoroethylene, which is easy to obtain and process.

[0046] When the manhole of the voltage stabilizer is opened, the centering device can be installed to ensure that the manhole cover of the voltage stabilizer does not slide down due to the lack of a force point, thereby avoiding the main bolt from getting stuck and the main bolt cannot be screwed out. The steps for using the centering device are as follows:

[0047] Step 1: Use the lifting device to roughly fix the position of the manhole cover or adjust the position to ensure that at least one of the 16 main bolts of the voltage stabilizer can be screwed out smoothly; then insert the centering device into the bolt hole; the threaded part contacts the screw hole sleeve, and the screw sleeve contacts the manhole cover;

[0048] Step 2: Use an S30 wrench to rotate, or use a φ12 lever to rotate the actuator; form the upper part of the eccentric rod and the screw sleeve as the support point. Due to the eccentric effect of the lower part of the eccentric rod and the screw sleeve, the manhole cover of the voltage stabilizer is forced to move during the rotation process. Closely observe whether the light hole of the manhole cover is concentric with the flange screw hole until the hole is concentric. At this time, the adjacent bolts can be screwed out smoothly;

[0049] Step 4: After unscrewing some of the bolts, if some of the bolts cannot be unscrewed, that is, other holes are still not concentric (i.e. circumferential misalignment), you can use another special tool to insert it into another hole to align the manhole cover of the voltage stabilizer circumferentially. In this way, all the main bolts can be unscrewed smoothly;

[0050] Step 5: After installing / removing the remaining main bolts, remove the tool.

[0051] The above is the hole opening operation, and the following will introduce the hole closing operation steps. It should be noted that when opening a hole, it is easy for the cover plate to sag after the nut of the bolt is loosened, causing the bolt to be stuck and unable to be screwed out. Using this tool, all bolts can be quickly and smoothly screwed out without considering whether the cover plate will sag. When closing a hole, due to hoisting and other tools, it is impossible to quickly adjust the parallelism and coaxiality of the cover plate and the manhole seat. Using this device, you can quickly achieve centering and screw in the bolts.

[0052] When closing the manhole of the voltage stabilizer, first use the lifting tool to center one hole in the manhole cover (rough centering is sufficient), and then use the tool to adjust the through hole of the manhole cover and the bolt hole of the manhole seat so that all main bolts can be screwed in smoothly. The specific steps are as follows:

[0053] Step 1: Use the lifting tool to ensure that at least one bolt in the 16 screw holes of the voltage stabilizer is aligned (visual observation is required at this time, and rough alignment is sufficient). Then insert the alignment tool into the bolt hole; the threaded part contacts the screw hole sleeve, and the screw sleeve contacts the manhole cover plate.

[0054] Step 2: Use an S30 wrench to rotate, or use a φ12 lever to rotate the actuator; the upper part of the eccentric rod and the screw sleeve are used as the supporting points. Due to the eccentric effect of the lower part of the eccentric rod and the screw sleeve, the manhole cover of the voltage stabilizer is forced to move during the rotation process. Closely observe whether the light hole of the manhole cover is concentric with the screw hole of the manhole seat until the holes are concentric;

[0055] Step 4: Observe whether the other holes are aligned, and screw in the bolts corresponding to the aligned holes; if there are any holes that are not aligned, use another tool to adjust them. Two tools can align all 16 holes;

[0056] Step 5: After installing some of the bolts, tighten them with at least 4 nuts, then remove the tool and continue to install the remaining bolts.

[0057] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A centering device for a manhole cover of a voltage stabilizer, characterized in that: The eccentric rod (1) comprises an eccentric rod (1) having a lower cylinder and an upper cylinder, a screw sleeve (2) being sleeved on the lower cylinder, a screw hole sleeve (3) being sleeved on the upper cylinder, and an actuator (6) being arranged below the eccentric rod (1) for realizing a rotational action.

2. The centering device for the manhole cover of a voltage stabilizer according to claim 1, characterized in that: The screw sleeve (2) and the screw hole sleeve (3) are fixed by a fixing nut (4) installed on the top of the upper cylinder.

3. The centering device for the manhole cover of a voltage stabilizer according to claim 2, characterized in that: A threaded hole is provided on the top of the upper cylindrical body, and the fixing nut (4) is fixed in cooperation with the threaded hole by a fixing screw (5).

4. The centering device for the manhole cover of a voltage stabilizer according to claim 1 or 2, characterized in that: The screw sleeve (2) and the lower cylinder are clearance-matched.

5. The centering device for the manhole cover of a voltage stabilizer according to claim 1 or 2, characterized in that: The screw hole sleeve (3) and the upper cylindrical body are clearance-matched.

6. The centering device for the manhole cover of a voltage stabilizer according to claim 1, characterized in that: The eccentric rod (1) has an operating mechanism, which comprises a hexagonal column with an operating hole and a hexagonal column without a hole.

7. The centering device for the manhole cover of a voltage stabilizer according to claim 1, characterized in that: The outer diameter of the upper cylinder is 30.8 mm, the outer diameter of the lower cylinder is 39 mm, and the eccentric distance between the upper cylinder and the lower cylinder is 2.7 mm.

8. The centering device for manhole cover of a voltage stabilizer according to claim 1, characterized in that: The thickness of the screw sleeve (2) and the screw hole sleeve (3) are both 5.5 mm, the outer diameter of the screw hole sleeve (3) is 42.4 mm, and the outer diameter of the screw sleeve (2) is 50 mm.

9. The centering device for the manhole cover of a voltage stabilizer according to claim 1, characterized in that: The material of the screw sleeve (2) and the screw hole sleeve (3) is polytetrafluoroethylene, and the material of the eccentric rod (1) is stainless steel.

10. A method for centering a manhole cover of a voltage stabilizer, characterized in that: The following steps are involved: Step 1: Fix the position of the manhole cover plate with a sling or adjust the position to ensure that at least one of the 16 main bolts of the voltage stabilizer is screwed out smoothly, insert the centering device of the manhole cover plate of the voltage stabilizer into the bolt hole, and make the threaded part contact with the screw hole sleeve, and the screw sleeve contact with the manhole cover plate; Step 2: Use an S30 wrench to rotate or a φ12 lever to rotate the actuator, forming a support point with the upper part of the eccentric rod and the screw hole sleeve. During the rotation, the manhole cover of the voltage stabilizer is forced to move. Observe whether the light hole of the manhole cover is concentric with the flange screw hole until the holes are concentric. At this time, the adjacent bolts can be screwed out smoothly; Step 4: After unscrewing some of the bolts, if some of the bolts cannot be unscrewed, use another stabilizer manhole cover centering device to insert it into another hole, so that the stabilizer manhole cover is circumferentially centered, so that all the main bolts can be unscrewed smoothly; Step 5: After removing the remaining main bolts, remove the centering device of the manhole cover of the voltage stabilizer.

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