A method and structure for preventing muddy water from entering the precise matching parts inside the shield knife-changing gate valve

Abstract

The present invention relates to a method for preventing muddy water from entering the precise fitting parts inside a shield knife-changing gate valve, the method is to inject sealing grease into the cavity formed by the outer cylinder of the roller cutter and the valve body on the muddy and water side, the valve body on the tool-changing side and the left and right gate plates, so that the sealing grease is filled and reaches the precise fitting parts, and the sealing grease is used to prevent the external muddy water from contacting the precise fitting parts during the roller cutter replacement process, thereby protecting the precise fitting parts inside the shield knife-changing gate valve; it also relates to a shield knife-changing gate valve structure that prevents muddy water from entering the precise fitting parts inside, an oil filling hole and an inspection hole are arranged on the valve body on the tool-changing side, and the oil filling hole and the inspection hole are respectively connected to the split gate valve. The method, matching grease and structure of the present invention can effectively prevent muddy water outside the shield machine from entering the precise fitting parts inside the gate valve, avoid the gate valve from getting stuck or the seal is damaged, and avoid major safety accidents such as flooding of the shield machine due to gate valve leakage.

Description

Technical Field

[0001] The invention relates to a shield machine, and in particular to a method for preventing muddy water from entering the precise matching parts inside a shield tool changing gate valve during a normal pressure tool changing process of the shield machine, and matching sealing grease and structure. Background Art

[0002] In national key shield construction projects with ultra-long distances and ultra-deep depths, the normal pressure knife-changing process is an indispensable key process and method. At the same time, in construction cases using the normal pressure knife-changing process at home and abroad, it is not uncommon for the knife-changing gate valve to fail in sealing or even get stuck due to muddy water entering the precision matching parts inside the normal pressure knife-changing gate valve. So far, there is no simple and effective method to truly prevent muddy water from entering the precision matching parts inside the knife-changing gate valve.

[0003] like Figure 1 and Figure 2 As shown, in the prior art, there are precise matching parts between the split gate valve of the normal pressure knife-changing gate valve and the valve body on the knife-changing side and the valve body on the mud-water side, such as: the narrow gap between the gate plate and the valve body; the sealing matching surface of the large end face of the gate plate; the sealing matching surface of the small end face of the gate plate; the U-shaped sealing matching surface that matches the gate plate, etc. The precise matching parts mainly realize the sealing and guiding of the relative moving parts, ensure the relative positions of the moving parts and prevent the mud and water from flowing into the shield machine. During the normal operation of the roller cutter, the external mud and water enter the interior of the knife-changing gate valve through the gap between the roller cutter barrel and the valve body on the mud-water side (such as Figure 1 In addition, when the gate is opened during the tool change process, muddy water inevitably enters the tool change gate valve, causing damage to the precision fitting parts due to the entry of muddy water. Figure 2 This causes the knife-changing gate valve structure to fail and a large amount of external mud and water to flow into the shield machine, flooding it. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method, matching sealing grease and a knife-changing gate valve structure that can prevent muddy water from entering the internal precision parts of the knife-changing valve. The method and structure of the present invention can effectively play a sealing role when replacing the roller cutter of the normal pressure knife-changing gate valve, realize the isolation of the internal precision parts from muddy water, thereby achieving the function of reducing damage and improving the efficiency of knife-changing.

[0005] In order to achieve the above invention purpose, the technical solution provided by the present invention is as follows:

[0006] A method for preventing mud and water from entering a precision fitting part inside a shield tool changing gate valve. The shield tool changing gate valve structure includes a tool changing side valve body, a mud and water side valve body and a split gate valve. The split gate valve is sandwiched between the tool changing side valve body and the mud and water side valve body. The split gate valve includes two side gate plates that can be opened to both sides at the same time. A precision fitting part is provided between the split gate valve and the tool changing side valve body and the mud and water side valve body. A roller cutter on a shield machine is retracted from the shield tool changing gate valve through a roller cutter cylinder to achieve tool changing. The method is to inject sealing grease into a cavity formed by an outer cylinder of the roller cutter and the mud and water side valve body, the tool changing side valve body and the edges of the two side gate plates, so that the sealing grease fills the cavity and reaches the precision fitting part. During the roller cutter replacement process, the sealing grease is used to prevent external mud and water from contacting the precision fitting part, thereby achieving protection of the precision fitting part inside the shield tool changing gate valve.

[0007] The above method for preventing muddy water from entering the precision matching parts inside the shield knife-changing gate specifically includes the following implementation steps:

[0008] The first step is to set an oil filling hole and an inspection hole on the tool-changing side valve body of the shield tool-changing gate valve, and the oil filling hole and the inspection hole are respectively connected to the split gate valve;

[0009] Step 2: Before the shield machine leaves the factory, the cutter drum is inserted into the shield knife-changing gate valve. At this time, the split gate valve is in the open position until the cutter drum is installed in place and the cutter is extended from the knife-changing gate valve. At this time, a cavity is formed in the shield knife-changing gate valve, which is composed of the outer cylinder of the cutter drum and the valve body on the mud and water side, the valve body on the knife-changing side and the edge of the split gate valve;

[0010] Step 3: Use a grease gun to inject sealing grease into the cavity through the oil filling hole until the sealing grease fills the entire cavity. The filling criterion is that the sealing grease overflows from the inspection hole;

[0011] Step 4: When the roller cutter is worn and needs to be replaced with a new one, the roller cutter drum is retracted from the shield knife-changing gate valve, and when it is returned to the rear of the split gate valve, the split gate valve is closed to block the mud and water outside. The presence of sealing grease prevents the mud and water from entering the split gate valve and the precise matching parts between the valve body on the knife-changing side and the valve body on the mud and water side. The roller cutter drum continues to retract to leave the shield knife-changing gate valve, disassemble and replace the roller cutter, and at the same time clean up the mud and water and part of the sealing grease that enter the knife-changing gate with the roller cutter drum;

[0012] Step 5: The cutter cylinder of the replaced cutter is inserted into the shield cutter changing gate valve. At this time, the gate valve is in a closed state. A small amount of sealing grease is injected through the oil filling hole using a grease gun to compensate for the loss of sealing grease.

[0013] Step 6. Open the split gate valve and extend the cutter cylinder forward to install the cutter in place. At this time, the split gate is in the open position, and a cavity is re-formed between the outer circle of the cutter cylinder and the valve body on the mud and water side, the valve body on the tool changing side and the edge of the split gate valve. Use the grease gun again to inject a specific volume of sealing grease into the cavity through the oil filling hole until the sealing grease fills the cavity. The volume of injected grease = gate height * gate width * gate stroke * 1.1.

[0014] The present invention also designs a shield tool-changing gate valve structure that prevents mud and water from entering the internal precision fitting parts. The shield tool-changing gate valve structure includes a tool-changing side valve body, a mud and water side valve body and a split gate valve. The split gate valve is clamped between the tool-changing side valve body and the mud and water side valve body. The split gate valve includes two side gate plates that open simultaneously. The split gate valve has a precision fitting part with the tool-changing side valve body and the mud and water side valve body. The roller cutter on the shield machine is retracted from the shield tool-changing gate valve through the roller cutter cylinder to achieve tool changing. An oil filling hole and an inspection hole are arranged on the tool-changing side valve body. The oil filling hole and the inspection hole are respectively connected to the split gate valve.

[0015] In a shield tool-changing gate structure for preventing mud and water from entering the internal precision fitting parts of the present invention, as a first implementation method, four triangular areas are enclosed by the circular outer wall of the roller cutter cylinder and the edges of the tool-changing side valve body, the mud and water side valve body and the gate plates on both sides. An oil filling hole and an inspection hole are respectively arranged on the tool-changing side valve body corresponding to each triangular area. The oil filling hole is located at the bottom of the triangular area, and the inspection hole is located at the top of the triangular area.

[0016] In a shield knife-changing gate structure for preventing muddy water from entering the internal precision fitting parts of the present invention, for the first arrangement of the oil filling hole and the inspection hole, the oil filling hole adopts a grease nozzle structure to inject sealing grease into the cavity through a grease gun. The inspection hole adopts a threaded plus wire plug structure.

[0017] In a shield tool changing gate structure for preventing mud and water from entering the internal precision fitting parts of the present invention, as another implementation method, four triangular areas are enclosed by the cylindrical outer wall of the cutter drum and the edges of the tool changing side valve body, the mud and water side valve body and the gate plates on both sides, and oil filling holes are respectively arranged on the tool changing side valve bodies corresponding to the two lower triangular areas, and inspection holes are respectively arranged on the tool changing side valve bodies corresponding to the two upper triangular areas, the oil filling holes are located at the lowermost side of the triangular area, and the inspection holes are located at the uppermost side of the triangular area.

[0018] In a shield knife-changing gate structure for preventing muddy water from entering the internal precision fitting parts of the present invention, as another implementation method, the circular outer wall of the roller cutter drum and the knife-changing side valve body, the muddy water side valve body and the gate plates on both sides enclose four triangular areas, and an oil filling hole is arranged on the knife-changing side valve body corresponding to any one of the lower triangular areas, and an inspection hole is arranged in a triangular area above the diagonal. The oil filling hole is located at the bottom of the triangular area, and the inspection hole is located at the top of the triangular area.

[0019] In a shield knife-changing gate valve structure for preventing muddy water from entering the internal precision fitting parts of the present invention, the sealing grease is XBYZ513, the soap base component of which is a lithium calcium compound. According to the ASTM D 4049 standard, a washout test is performed using artificial seawater at 38°C, and the mass loss rate is less than or equal to 7%. According to GB / T269-91, its cone penetration is between 130-280.

[0020] Based on the above technical solution, the present invention provides a shield knife-changing gate valve method and structure for preventing mud and water from entering the internal precision matching parts, which has achieved the following technical effects compared with the prior art:

[0021] 1. In order to solve the problem that muddy water enters into the internal precision fitting parts and causes damage when the normal pressure knife-changing gate valve is used, the patent of this invention sets an oil filling hole and an inspection hole on the valve body on the knife-changing side. When the roller cutter is installed in the knife-changing gate valve, specially formulated XBYZ513 is injected from the oil filling hole until the grease overflows from the inspection hole to ensure that the cavity between the outer cylinder of the roller cutter and the valve body on the muddy and water side, the valve body on the knife-changing side and the left and right gate plates is filled with sealing grease XBYZ513, and the sealing grease is used to prevent muddy water from entering the internal precision fitting parts of the normal pressure knife-changing gate valve.

[0022] 2. The method, matching grease and structure of the present invention can effectively prevent mud and water on the outside of the shield machine from entering the precise fitting parts inside the gate valve, avoid jamming or sealing damage of the gate valve, and also avoid major safety accidents such as flooding of the shield machine due to gate valve leakage. It has high operability and practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It refers to the schematic diagram of muddy water entering the normal pressure knife-changing gate valve when the hob is working normally.

[0024] Figure 2 It refers to the schematic diagram of muddy water entering the interior of the normal pressure knife-changing gate valve when the double gate valve of the normal pressure knife-changing gate valve is opened during the process of replacing the hob.

[0025] Figure 3 It is a schematic diagram of Example 1 of a shield knife-changing gate structure of the present invention for preventing mud and water from entering an internal precision fitting part.

[0026] Figure 4 It is a schematic diagram of Example 2 of a shield knife-changing gate structure of the present invention for preventing mud and water from entering an internal precision fitting part.

[0027] Figure 5 It is a schematic diagram of Example 3 of a shield knife-changing gate structure of the present invention for preventing mud and water from entering an internal precision fitting part.

[0028] Figure 6 The present invention is a schematic diagram of the assembly and grease injection process of the roller cutter and the normal pressure knife-changing gate valve before leaving the factory in a method for preventing muddy water from entering the precise matching parts inside the shield knife-changing gate of the present invention.

[0029] Figure 7 It is a schematic diagram of the process of retracting the roller cutter and changing the cutter in a method for preventing mud and water from entering the precise fitting parts inside the cutter changing gate of a shield machine according to the present invention.

[0030] Figure 8 It is a schematic diagram of the process of replacing a new roller cutter and injecting grease in a method for preventing mud and water from entering a precise matching part inside a shield cutter changing gate of the present invention.

[0031] Among them, 1-valve body on the tool change side 2-open gate valve 3-oil filling hole 4-inspection hole 5-valve body on the mud and water side 6-roller cylinder 7-roller 8-mud and water DETAILED DESCRIPTION

[0032] Below we will further elaborate on the method of preventing mud and water from entering the precise fitting parts inside the shield machine normal pressure knife-changing gate valve and the matching sealing grease and structure in combination with the accompanying drawings and specific embodiments, so as to more clearly understand its structural composition and working mode, but this cannot be used to limit the scope of protection of the present invention.

[0033] like Figure 1 and Figure 2 As shown, in the shield equipment, the shield normal pressure knife-changing gate structure includes a knife-changing side valve body 1, a mud-water side valve body 5 and a split gate valve 2, wherein the split gate 2 is sandwiched between the knife-changing side valve body 1 and the mud-water side valve body 5, and the split gate valve 2 includes two gate plates that can be opened to both sides at the same time, and there is a precise matching part between the split gate valve 2 and the knife-changing side valve body 1 and the mud-water side valve body 5, and the roller cutter 7 on the shield machine is retracted from the shield knife-changing gate valve through the roller cutter cylinder 8 to achieve knife change. During normal operation, the split gate plate is opened, and the roller cutter passes through the normal pressure knife-changing gate valve to cut the rock and soil. At this time, the mud and water from the outside will enter the precise matching part inside the knife-changing gate valve through the gap between the roller cutter and the mud-water side valve body. In addition, when replacing the roller cutter, the mud and water from the outside will inevitably enter the precise matching part inside the knife-changing gate valve as the roller cutter retreats. Muddy water that enters the precision fitting parts inside the knife-changing gate valve will jam the movement of the gate and destroy the seal inside the knife-changing gate valve.

[0034] The present invention first provides a method for preventing muddy water from entering the precise fitting parts inside the shield knife-changing gate valve. The idea is to prevent external muddy water from entering the precise fitting parts inside the knife-changing gate valve structure by injecting dense sealing grease. The method specifically injects sealing grease into the cavity formed by the outer cylinder of the hob and the valve body on the muddy and water side, the valve body on the knife-changing side and the edge of the split gate valve, so that the sealing grease fills and reaches the precise fitting parts. During the hob replacement process, the sealing grease is used to prevent external muddy water from contacting the precise fitting parts, thereby protecting the precise fitting parts inside the shield knife-changing gate valve. The hob cylinder is cylindrical in shape as a whole, so the hob cylinder also serves as the outer cylinder of the hob.

[0035] The above method for preventing muddy water from entering the precision fitting parts inside the shield knife-changing gate valve specifically includes the following implementation steps:

[0036] Before the shield leaves the factory:

[0037] The first step is to set an oil filling hole 3 and an inspection hole 4 on the tool-changing side valve body 1 of the shield tool-changing gate valve, and the oil filling hole 3 and the inspection hole 4 are respectively connected inward to the split gate valve 2;

[0038] The second step is to extend the cutter drum 6 into the cutter-changing gate valve structure, open the split gate valve 2, and install the cutter in place. At this time, a cavity is formed between the cutter outer cylinder of the cutter drum 6 and the mud-water side valve body 5, the cutter-changing side valve body 1 and the edge of the split gate valve 2. At this time, the assembled cutter can be installed on the cutterhead of the shield machine together with the normal pressure cutter-changing gate valve.

[0039] The third step is to use a grease gun to inject sealing grease into the cavity of the shield knife-changing gate valve through the oil filling hole 3 until the sealing grease fills the entire cavity. The judgment standard is that the sealing grease overflows from the inspection hole 4, indicating that the cavity is full.

[0040] During the shield operation, when it is necessary to remove the worn roller cutter and replace it with a new one:

[0041] The first step is that when the cutter 7 is worn out after long-term use and needs to be replaced with a new one, the cutter cylinder 6 retracts from the cutter changing gate valve. After returning to the rear of the opened split gate valve 2, the split gate valve 2 needs to be closed to block the muddy water 8 outside the split gate valve 2. At this time, the presence of sealing grease prevents the muddy water 8 from entering the precise fitting parts between the gate plates on both sides of the split gate valve 2 and the valve body 1 on the cutter changing side and the valve body 5 on the muddy water side.

[0042] In the second step, the cutter drum 6 is further retracted to leave the knife-changing gate valve, and the cutter drum 7 is disassembled and replaced, and at the same time, the muddy water and part of the sealing grease that enter the knife-changing gate valve along with the cutter drum 6 are cleaned.

[0043] During the shield operation, new roller cutters are installed.

[0044] The first step is to insert the cutter cylinder 6 of the replaced cutter 7 into the cutter changing gate valve, at which time the gate valve 2 is in a closed state. Use a grease gun to inject sealing grease into the cavity through the oil filling hole 3 to make up for the loss of some sealing grease caused by cleaning muddy water. The injection standard is that the sealing grease overflows from the inspection hole 4 to indicate that it is full.

[0045] The second step is to open the split gate valve 2 and install the roller cutter drum in place. At this time, the split gate 2 is in the open position, and a cavity is formed between the outer wall of the roller cutter drum and the valve body on the mud and water side, the valve body on the tool change side, and the end face of the split gate valve. Use the grease gun again to inject sealing grease into the cavity through the oil injection hole 3 until the sealing grease fills the entire cavity. At this time, the injection standard of the sealing grease is: inject a specific volume of grease, gate height * gate width * gate stroke) * 1.1 = the volume of injected grease.

[0046] The present invention also designs a shield knife-changing gate structure that prevents mud and water from entering the internal precision matching parts. The shield knife-changing gate structure includes a knife-changing side valve body 1, a mud and water side valve body 5 and a split gate valve 2. The split gate valve 2 is sandwiched between the knife-changing side valve body 1 and the mud and water side valve body 5. The split gate valve 2 includes two side gates that are opened at the same time, which can be moved to both sides at the same time to open the gate, and can also be moved to the middle at the same time to close the gate. There are precision matching parts between the split gate valve 2 and the knife-changing side valve body 1 and the mud and water side valve body 5, such as: a narrow gap between the gate and the valve body; a sealing matching surface of the large end face of the gate; a sealing matching surface of the small end face of the gate; a U-shaped sealing matching surface that matches the gate, etc. The precision matching parts mainly realize the sealing of the power components and prevent mud and water from flowing into the interior of the shield machine. The cutter roller 7 on the shield machine is retracted from the shield cutter changing gate through the cutter drum 6 to achieve cutter changing. The core innovative point of the present invention is that an oil filling hole 3 and an inspection hole 4 are arranged on the cutter changing side gate body 1, and the oil filling hole 3 and the inspection hole 4 are respectively connected to the split gate valve 2, so that the purpose of injecting sealing grease into the shield cutter changing gate structure through the oil filling hole 3 can be achieved. The sealing grease can prevent mud and water from entering the precise fitting parts inside the gate valve when the cutter drum passes through the cutter changing gate valve structure.

[0047] Example 1

[0048] like Figure 3As shown, in the shield tool-changing gate structure that prevents mud and water from entering the internal precision fitting parts in this embodiment, an oil filling hole 3 and an inspection hole 4 are arranged on the tool-changing side valve body 1, and the oil filling hole 3 and the inspection hole 4 are respectively connected to the split gate valve 2, so that the purpose of injecting sealing grease into the shield tool-changing gate valve structure through the oil filling hole 3 can be achieved, and the sealing grease is used to block the mud and water in the process of the roller cutter barrel passing through the tool-changing gate valve structure. The cylindrical outer wall of the roller cutter barrel 6, the four triangular areas surrounded by the tool-changing side valve body 1, the mud and water side valve body 5 and the split gate valve 2, and the tool-changing side valve body corresponding to each triangular area are respectively arranged with an oil filling hole 3 and an inspection hole 4, wherein the oil filling hole 3 is located at the bottom of the triangular area, and the inspection hole is located at the top of the triangular area.

[0049] For the first arrangement of the oil filling hole and the inspection hole, the oil filling hole 3 adopts a grease nozzle structure, so that the sealing grease is injected into the cavity through a grease gun as a grease gun. The inspection hole 4 adopts a threaded plus wire plug structure, which can be closed with a wire plug when the sealing grease is filled, so as to avoid leakage of the sealing grease during use.

[0050] Example 2

[0051] like Figure 4 As shown, in a shield knife-changing gate structure for preventing muddy water from entering the internal precision fitting parts of the present invention, as another implementation method, the cylindrical outer wall of the roller cutter barrel 6 and the side walls of the knife-changing side valve body 1, the muddy side valve body 5 and the gate plates on both sides of the split gate valve 2 form four triangular areas. As a composition form, the knife-changing side valve body 1 corresponding to the two lower triangular areas is respectively provided with oil filling holes 3, and the knife-changing side valve body corresponding to the two upper triangular areas is respectively provided with inspection holes 4.

[0052] The oil injection hole 3 is located at the bottom of the triangular area, and the oil injection hole 3 adopts a grease nozzle structure to inject sealing grease into the cavity through a grease gun. The inspection hole 4 adopts a threaded and plugged structure and is located at the top of the triangular area.

[0053] Example 3

[0054] like Figure 5As shown, in the shield tool-changing gate valve structure that prevents mud and water from entering the internal precision fitting parts in this embodiment, an oil filling hole 3 and an inspection hole 4 are arranged on the tool-changing side valve body 1, and the oil filling hole 3 and the inspection hole 4 are respectively connected to the split gate valve 2, so that the purpose of injecting sealing grease into the shield tool-changing gate structure through the oil filling hole 3 can be achieved, and the sealing grease can be used to block mud and water during the process of the roller cutter barrel passing through the tool-changing gate structure. The outside of the roller cutter barrel 6, the four triangular areas surrounded by the tool-changing side valve body 1, the mud and water side valve body 5 and the inner edges of the gate plates on both sides of the split gate valve 2, an oil filling hole is arranged on the tool-changing side valve body corresponding to the lower triangular area, and the oil filling hole 3 is located at the bottom of the triangular area. An inspection hole 4 is arranged on the tool-changing side valve body corresponding to the upper triangular area of ​​the diagonal of the lower triangular area, and the inspection hole 4 is located at the top of the triangular area.

[0055] In the present invention, the sealing grease is a key component, which seals the outer side of the roller cutter drum and the blade changing gate structure, thereby preventing muddy water from entering the blade changing gate structure. In practice, the sealing grease is XBYZ513, the soap base component is a lithium calcium compound, and the ASTM D 4049 standard is used to perform a washout test with artificial seawater at 38°C, and the mass loss rate is less than or equal to 7%. According to GB / T269-91, its cone penetration is between 130-280. Commonly used sealing greases can be selected from CONDAT's HBW; WR89; WR90; TOTAL's PX3340; ADERIA TM-T; ADERIA PA; MATSUMURA's #8000NP, and other products with equivalent performance can also be selected.

[0056] The present invention sets up an oil filling hole and an inspection hole on the valve body on the tool-changing side. When the roller cutter is installed in place, specially formulated XBYZ513 is injected from the oil filling hole until the grease overflows from the inspection hole. This ensures that the cavity between the outer cylinder of the roller cutter and the valve body on the muddy and water side, the valve body on the tool-changing side, and the left and right gate plates is filled with sealing grease XBYZ513. The use of the method and the matching grease and structure of the present invention can effectively prevent the muddy and water on the outside of the shield machine from entering the precise matching parts inside the gate valve, avoid the jamming or sealing damage of the gate valve, and avoid major safety accidents such as flooding of the shield machine due to gate valve leakage. It has high operability and practical value.

[0057] Undoubtedly, the above are only several specific implementation forms of the shield knife gate changing method and structure for preventing muddy water from entering the internal precision matching parts of the present invention. In addition, there may be other implementation methods and structures based on the same idea. In short, the protection scope of the present invention also includes other obvious changes and substitutions for those skilled in the art.

Claims

1. A method for preventing muddy water from entering the precision fitting part inside the shield knife-changing gate valve, the shield knife-changing gate valve structure includes a knife-changing side valve body, a muddy water side valve body and a split gate valve, the split gate valve is sandwiched between the knife-changing side valve body and the muddy water side valve body, the split gate valve includes two side gate plates that can be opened to both sides at the same time, and there is a precision fitting part between the split gate valve and the knife-changing side valve body and the muddy water side valve body. The roller cutter on the shield machine is retracted from the shield knife-changing gate valve through the roller cutter cylinder to achieve knife changing. The method is to inject sealing grease into the cavity formed by the outer cylinder of the roller cutter and the muddy water side valve body, the tool-changing side valve body and the edges of the two side gate plates, so that the sealing grease fills the cavity and reaches the precision fitting part, and the sealing grease is used to prevent external muddy water from contacting the precision fitting part during the roller cutter replacement process, so as to protect the precision fitting part inside the shield knife-changing gate valve. The method specifically includes the following implementation steps: The first step is to set an oil filling hole and an inspection hole on the tool-changing side valve body of the shield tool-changing gate valve, and the oil filling hole and the inspection hole are respectively connected to the split gate valve; Step 2: Before the shield machine leaves the factory, the cutter drum is inserted into the shield knife-changing gate valve. At this time, the split gate valve is in the open position until the cutter drum is installed in place and the cutter is extended from the knife-changing gate valve. At this time, a cavity is formed in the shield knife-changing gate valve, which is composed of the outer cylinder of the cutter drum and the valve body on the mud and water side, the valve body on the knife-changing side and the edge of the split gate valve; Step 3: Use a grease gun to inject sealing grease into the cavity through the oil filling hole until the sealing grease fills the entire cavity. The filling criterion is that the sealing grease overflows from the inspection hole; Step 4: When the roller cutter is worn and needs to be replaced with a new one, the roller cutter drum is retracted from the shield knife-changing gate valve, and when it is returned to the rear of the split gate valve, the split gate valve is closed to block the mud and water outside. The presence of sealing grease prevents the mud and water from entering the split gate valve and the precise matching parts between the valve body on the knife-changing side and the valve body on the mud and water side. The roller cutter drum continues to retract to leave the shield knife-changing gate valve, disassemble and replace the roller cutter, and at the same time clean up the mud and water and part of the sealing grease that enter the knife-changing gate with the roller cutter drum; Step 5: The cutter cylinder of the replaced cutter is inserted into the shield cutter changing gate valve. At this time, the gate valve is in a closed state. A small amount of sealing grease is injected through the oil filling hole using a grease gun to compensate for the loss of sealing grease. Step 6. Open the split gate valve and extend the cutter cylinder forward to install the cutter in place. At this time, the split gate is in the open position, and a cavity is re-formed between the outer circle of the cutter cylinder and the valve body on the mud and water side, the valve body on the tool changing side and the edge of the split gate valve. Use the grease gun again to inject a specific volume of sealing grease into the cavity through the oil filling hole until the sealing grease fills the cavity. The volume of injected sealing grease = gate height * gate width * gate stroke * 1.1.

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