Automatic centering flexible grinding device for inner wall of liquid rocket engine conduit

Abstract

The invention belongs to the technical field of pipeline inner wall treatment, and particularly relates to a liquid rocket engine conduit inner wall automatic centering flexible grinding device which comprises a grinding head, a flexible shaft, a centering ring, a heat shrink tube and a transmission rod. The two ends of the flexible shaft are connected with the grinding head and the transmission rod respectively in a welded mode, and the transmission rod is connected with a common electric tool and provides power for the whole device. The concentricity of the flexible shaft and the grinding head can be guaranteed through the centering ring and the specially-designed grinding head shape, and the grinding precision can be guaranteed through the specially-designed grinding head size. The outer surfaces of the flexible shaft and the grinding head are coated with a layer of heat shrink tube to ensure that the inner wall of the conduit is scratched when the grinding head enters a grinding area through the pipe diameter. By means of the device, the liquid rocket engine guide pipe inner wall weld joint corrosion part and the inner welding leakage are polished, the quality and the drift diameter of the liquid rocket engine guide pipe inner wall meet the use requirements, the production bottleneck is solved, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipeline inner wall treatment, and particularly relates to an automatic centering and grinding device for the rusted parts of the inner wall welds and internal welding leaks of the ducts of liquid rocket engines. Background Technique

[0002] Due to the flow requirements of the ducts of liquid rocket engines and the high-temperature and high-pressure characteristics of the internal fluid, the duct materials include special steels such as 1Cr18Ni9Ti, S-03, S-06, and GH202. Therefore, during production, it is necessary to strictly ensure the inner diameter range of the inner wall and the cleanliness of the inside of the duct, and it is necessary to grind the inner wall of the duct. However, these ducts are often non-linear, have a small inner diameter and a long length, and existing grinding tools such as angle grinders and rotary files cannot solve this problem. Therefore, some ducts with excessive internal welding leaks or rusted inner wall welds will face scrapping. In this case, only manual grinding with sandpaper or files can be used, which is time-consuming and laborious and increases the labor cost.

[0003] At present, there has appeared a device that uses a flexible shaft to transmit the output power of a driving motor and drives a grinding head to rotate for grinding work. However, the grinding heads used are all wire brushes or non-woven fabrics, and are mainly used to remove surface oxide scales and oxidation colors. For the rusted parts of the inner wall welds and internal welding leaks of metal ducts, the existing grinding heads have low efficiency and short service life. Moreover, the flexible shaft lacks restraint, and the concentricity and centering are not good, and it cannot meet the requirements of the ducts of liquid rocket engines for the inner diameter and cleanliness. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: aiming at the problem that the existing grinding equipment is not suitable for grinding the inner wall of small-diameter ducts of liquid rocket engines, an automatic centering and flexible grinding device for the rusted parts of the inner wall welds and internal welding leaks of the ducts of liquid rocket engines is provided.

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

[0006] An automatic centering and flexible grinding device for the inner wall of a duct of a liquid rocket engine, comprising a grinding head, a flexible shaft, a centering ring, a heat shrinkable tube, and a transmission rod. One end of the flexible shaft is welded to the grinding head, and the other end is welded to the transmission rod. The transmission rod can be connected to an electric tool;

[0007] The centering ring is sleeved on the outer wall of the flexible shaft to ensure the concentricity and centering of the flexible shaft and the grinding head;

[0008] Before the grinding head enters the grinding area through the diameter of the engine duct, the heat shrinkable tube is coated on the outer surface of the flexible grinding device to prevent the inner wall of the duct from being scratched during the process of the grinding head entering the engine duct; after reaching the position, the heat shrinkable tube is removed and grinding starts; after grinding is completed, the heat shrinkable tube is coated on the outer surface of the flexible grinding device to prevent the inner wall of the duct from being scratched during the process of the grinding head withdrawing from the engine duct.

[0009] Preferably, the grinding head is in the shape of a frustum of a cone.

[0010] Preferably, the small end diameter of the grinding head is d1, the large end diameter is d2, and the inner diameter of the engine conduit is D. d2 should satisfy 0.6D ≤ d2 ≤ 0.9D, and d1 should satisfy 0.5d2 ≤ d1 ≤ 0.85d2.

[0011] Preferably, the length of the grinding head is l, and l = 1.5d2.

[0012] Preferably, the outer diameter of the centering ring is d3, the inner diameter is d4, the outer diameter of the flexible shaft is d5, and the inner diameter of the engine conduit is D. d3 = D - 1 mm, and d4 should satisfy d4 = d5 + 1 mm.

[0013] Preferably, the frustum-shaped grinding head is made of high-speed steel.

[0014] Preferably, the flexible shaft is made of steel No. 60 or 65 or 70 or 75.

[0015] Preferably, the centering ring is made of polytetrafluoroethylene.

[0016] Preferably, the transmission rod is connected to the power tool through a hexagonal prism joint at the end.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The grinding device of the present invention has a specially designed grinding head (size and shape). The size of the small end of the grinding head ensures that the grinding head can penetrate into the position of the internal welding leakage in the elbow pipe, while ensuring the concentricity and alignment of the transmission. The size of the large end of the grinding head ensures the through-diameter requirement of the conduit after grinding. The grinding head is made of high-speed steel, which improves the efficiency of grinding the rusty parts and internal welding leakage on the inner wall of the metal conduit, and makes the through-diameter of the conduit meet the requirements of QJ919A-98.

[0019] 2. The grinding device of the present invention has a specially designed centering ring, which is installed on the outer wall of the flexible shaft, and can ensure the concentricity and alignment of the flexible shaft and the grinding head.

[0020] 3. The grinding head and the flexible shaft, and the flexible shaft and the transmission rod of this device are connected by welding, which avoids the relative position change and dragging during work, resulting in the flexible shaft falling off, and ensures the stability and reliability of the transmission.

[0021] 4. When the heat shrinkable tube of this device enters and exits the grinding part through the pipe diameter, it covers the outer surface of the grinding head, avoiding scratching the inner wall of the conduit. It can meet the requirements of the liquid rocket engine pipeline for through-diameter and cleanliness. Description of the Drawings

[0022] Figure 1 is a schematic structural diagram of the present invention;

[0023] Figure 2 It is a schematic diagram of the usage method of the present invention;

[0024] In the figure: 1 - grinding head, 2 - flexible shaft, 3 - centering ring, 4 - transmission rod, 5 - heat shrinkable tube. Specific implementation manner

[0025] As Figure 1 shown, a flexible grinding device for automatically centering the rusted parts and internal welding leaks on the inner wall of a liquid rocket engine duct includes a grinding head, a flexible shaft, a centering ring, a heat shrinkable tube and a transmission rod. The two ends of the flexible shaft are respectively connected to the grinding head and the transmission rod by welding, and the transmission rod can be connected to common electric tools.

[0026] The grinding head is in the shape of a frustum. The frustum-shaped grinding head is made of high-speed steel such as W18Cr4V and W6Mo5Cr4V. The centering ring 3 is sleeved on the outer wall of the flexible shaft, and the distance between the centering ring and the large end of the grinding head is less than 10 mm, which is used to ensure the concentricity and alignment of the flexible shaft and the grinding head.

[0027] The entire flexible shaft is made of steel No. 60 or 65 or 70 or 75. The centering ring is made of polytetrafluoroethylene. The transmission rod is connected to common electric tools through a hexagonal prism joint at the end.

[0028] The small end diameter of the grinding head is d1, the large end diameter is d2, and the inner diameter of the pipe is D. The selected d2 of the grinding head should satisfy 0.6D ≤ d2 ≤ 0.9D, and d1 should satisfy 0.5d2 ≤ d1 ≤ 0.85d2.

[0029] The large end diameter of the grinding head is d2, and the length is l, l = 1.5d2.

[0030] The outer diameter of the centering ring is d3, the inner diameter is d4, and the outer diameter of the flexible shaft is d5. The selected d3 of the centering ring should satisfy d3 = D - 1, and d4 should satisfy d4 = d5 + 1.

[0031] The heat shrinkable tube is coated on the outer surface of the grinding head when the grinding head enters the welding leak part through the pipe diameter, so as to avoid scratching the inner wall of the duct. After the grinding is completed and the grinding head is withdrawn, the heat shrinkable tube is coated on the outer surface of the grinding head to avoid scratching the inner wall of the duct.

[0032] Figure 2 It is a schematic diagram of the usage method of the present invention. It can be applied to straight engine ducts or bent pipes.

[0033] The catheter materials include special steel materials such as 1Cr18Ni9Ti, S-03, S-06, and GH202. The transmission rod is connected to common power tools to provide power for the entire device. Finding the center ring and the specially designed grinding head shape can ensure the concentricity of the flexible shaft and the grinding head, and the specially designed grinding head size can ensure the grinding accuracy. A heat shrinkable tube is coated on the outer surfaces of the flexible shaft and the grinding head to ensure that the inner wall of the catheter is not scratched when the grinding head enters the grinding area through the pipe diameter. With this device, the rusted parts and internal welding leaks of the inner wall welds of the liquid rocket engine catheter are ground, so that the quality and diameter of the inner wall of the liquid rocket engine catheter meet the usage requirements, solving the production bottleneck and improving the production efficiency and service life.

[0034] The parts not described in detail in the present invention belong to the common general knowledge of those skilled in the art.

Claims

1. An automatic centering flexible grinding device for the inner wall of a liquid rocket engine duct, characterized in that: It includes a grinding head (1), a flexible shaft (2), a centering ring (3), a heat shrinkable tube (5) and a transmission rod (4). One end of the flexible shaft (2) is welded to the grinding head, and the other end is welded to the transmission rod (4). The transmission rod (4) can be connected to a power tool. The centering ring (3) is sleeved on the outer wall of the flexible shaft to ensure the concentricity and alignment of the flexible shaft and the grinding head. Before the grinding head enters the grinding area through the inner diameter of the engine conduit, the heat shrinkable tube (5) is wrapped around the outer surface of the flexible grinding device to prevent the inner wall of the conduit from being scratched when the grinding head enters the engine conduit. After entering in place, the heat shrinkable tube (5) is removed and grinding starts. After grinding is completed, the heat shrinkable tube (5) is wrapped around the outer surface of the flexible grinding device to prevent the inner wall of the conduit from being scratched when the grinding head is withdrawn from the engine conduit.

2. The automatic centering flexible grinding device for the inner wall of a liquid rocket engine duct according to claim 1, characterized in that: The grinding head is in the shape of a frustum of a cone.

3. The automatic centering flexible grinding device for the inner wall of a liquid rocket engine duct according to claim 2, characterized in that: The small end diameter of the grinding head is d1, the large end diameter is d2, and the inner diameter of the engine conduit is D. d2 should satisfy 0.6D ≤ d2 ≤ 0.9D, and d1 should satisfy 0.5d2 ≤ d1 ≤ 0.85d2.

4. The automatic centering flexible grinding device for the inner wall of a liquid rocket engine duct according to claim 3, wherein: The length of the grinding head is l, and l = 1.5d2.

5. The automatic centering flexible grinding device for the inner wall of a liquid rocket engine duct according to claim 4, wherein: The outer diameter of the centering ring is d3, the inner diameter is d4, the outer diameter of the flexible shaft is d5, and the inner diameter of the engine conduit is D. d3 = D - 1mm, and d4 should satisfy d4 = d5 + 1mm.

6. The automatic centering flexible grinding device for the inner wall of a liquid rocket engine duct according to claim 2, characterized in that: The frustum-shaped grinding head is made of high-speed steel.

7. The automatic centering flexible grinding device for the inner wall of a liquid rocket engine duct according to claim 1, characterized in that: The flexible shaft is made of steel No. 60 or 65 or 70 or 75.

8. The automatic centering flexible grinding device for the inner wall of a liquid rocket engine duct according to claim 1, wherein: The centering ring is made of polytetrafluoroethylene.

9. The automatic centering flexible grinding device for the inner wall of a liquid rocket engine duct according to claim 1, characterized in that: The transmission rod is connected to the power tool through a hexagonal prism joint at the end.

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