3D printing nozzle and printing method for printing contaminated site barrier

Abstract

The present invention belongs to the field of 3D printing nozzles, and discloses a 3D printing nozzle and printing method for printing a barrier for a contaminated site, which can achieve simultaneous rapid carbonization and printing construction of printing materials, form a composite barrier with a high sealing effect, and significantly improve the efficiency of emergency disposal of sudden soil and groundwater pollution incidents at the site. The 3D printing nozzle includes a shell, a hollow first stirring shaft, a hollow second stirring shaft, a power source, and an air source; the shell is provided with a material inlet, a material outlet, and an air injection hole; the outer wall of the second stirring shaft is provided with a second stirring blade, the second stirring shaft is fitted on the outside of the first stirring shaft, the lower outer wall of the first stirring shaft is provided with a first stirring blade, and the lower wall of the first stirring shaft is provided with a gas dispersion hole; the power source drives the first stirring shaft and the second stirring shaft to rotate; and the air source is connected to the hollow cavity and the air injection hole of the first stirring shaft respectively.

Description

Technical Field

[0001] The present invention relates to a 3D printing nozzle and a printing method, and in particular to a 3D printing nozzle and a printing method for printing a barrier to a contaminated site. Background Art

[0002] After an emergency soil and groundwater contamination incident at a site, rapid isolation of the site surface is an effective way to prevent the spread of contamination. The rapid construction of contaminated site barriers through information-based and mechanized 3D printing technology can effectively improve the efficiency of emergency response and reduce the harm to rescue personnel in traditional emergency response technologies. Currently, printing materials represented by cement-activated steel slag have the disadvantages of long molding time, and the cement component in the material has high energy consumption and high carbon emissions. Rapid carbonization technology can not only effectively improve the reactivity of cement-activated steel slag printing materials and enhance the service performance of printed barriers, but also achieve effective carbon fixation, with significant environmental benefits. However, the printability of the printing material after rapid carbonization is rapidly weakened, which will affect the high-quality printing construction of the subsequent barrier. Therefore, how to achieve the simultaneous rapid carbonization and printing construction of weakly reactive silicate printing materials represented by cement-activated steel slag has always been a technical challenge facing this field. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: in response to the shortcomings of the existing technology, a 3D printing nozzle and printing method for printing contaminated site barriers are provided, which can realize the simultaneous rapid carbonization and printing construction of the printing material, forming a composite barrier with a high sealing effect, and significantly improving the emergency response efficiency of sudden soil and groundwater pollution incidents at the site.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] In the first aspect, the present invention provides a 3D printing nozzle for printing a barrier to contaminated sites, comprising a shell, a hollow first stirring shaft, a hollow second stirring shaft, a power source and an air source; wherein, the shell is provided with an inlet, an outlet and an air injection hole; the second stirring shaft and the shell are connected by a bearing, the outer wall of the second stirring shaft is provided with a second stirring blade, and the second stirring blade is located in the inner cavity of the shell; the second stirring shaft is sleeved on the outside of the first stirring shaft, the first stirring shaft and the second stirring shaft are connected by a bearing, and there is a gap between the first stirring shaft and the second stirring shaft; the upper part of the first stirring shaft passes through the top end of the second stirring shaft, the lower part of the first stirring shaft passes through the bottom end of the second stirring shaft, the lower outer wall of the first stirring shaft is provided with a first stirring blade, the first stirring blade is located in the inner cavity of the shell, and the lower wall of the first stirring shaft is provided with a gas dispersion hole; the top of the first stirring shaft and the top of the second stirring shaft are respectively connected to the power source, and the power source drives the first stirring shaft and the second stirring shaft to rotate; the air source is respectively connected to the hollow cavity and the air injection hole of the first stirring shaft.

[0006] As a preferred example, the feed port is located on the upper side of the shell, and the discharge port is located at the bottom of the shell; the air injection holes are through holes, which are arranged obliquely upward from the outside to the inside of the shell; the air injection holes are arranged in multiple layers along the axis of the shell; and at least 3 air injection holes are provided in the first air injection hole of each layer.

[0007] As a preferred example, the 3D printing nozzle for printing a barrier to contaminated sites further includes a first pressure regulating valve, a connecting valve, a first connecting pipe, and a second connecting pipe, wherein one connecting valve is provided in each gas injection hole; in the gas injection holes located in the same layer, the connecting valves are connected through the first connecting pipe; the first connecting pipes of different layers are connected through the second connecting pipe; the gas source is connected to the first connecting pipe or the second connecting pipe through a fourth connecting pipe, and the first pressure regulating valve is provided in the fourth connecting pipe.

[0008] As a preferred example, an injection core assembly is provided in the injection hole, and the injection core assembly includes a fixing part, an outer shell, and a spring, a sealing plate and a core body located in the outer shell. The outer shell is fixed in the inner cavity of the first injection hole by a fixing part, one end of the spring is fixedly connected to one end of the outer shell, and the other end of the spring is fixedly connected to the sealing plate; the core body is provided with a hollow through hole, and the air inlet and air outlet ends of the core body are both open; the sealing plate and the air outlet end of the core body are opposite to each other, and the sealing plate can seal the air outlet end of the core body; the air inlet end of the core body is connected to the connecting valve.

[0009] As a preferred example, the power source includes a motor with a power output shaft, a first gear and a second gear, the first gear is fixedly connected to the upper outer wall of the first stirring shaft, and the second gear is fixedly connected to the upper outer wall of the second stirring shaft; the power output shaft is respectively adapted to the first gear and the second gear, driving the first gear and the second gear to rotate in opposite directions; it also includes a third connecting pipe and a second pressure regulating valve, the air source is connected to the hollow cavity of the first stirring shaft through the third connecting pipe, and the second pressure regulating valve is arranged in the third connecting pipe; it also includes a first sealing ring and a second sealing ring, the first sealing ring is embedded between the first stirring shaft and the second stirring shaft, and is located at the bottom of the inner cavity of the second stirring shaft; the second sealing ring is embedded between the second stirring shaft and the shell.

[0010] In a second aspect, the present invention further provides a method for printing a barrier, wherein the barrier comprises, from bottom to top, a first carrier layer, a stain-blocking layer, and a second carrier layer; the method comprising:

[0011] Step 1: Use a 3D printing nozzle to build the first bearing layer;

[0012] Step 2: Using a 3D printing nozzle to build a pollution-resistant layer above the first supporting layer;

[0013] Step 3: Use a 3D printing nozzle to build a second supporting layer above the anti-fouling layer.

[0014] As a preferred example, the step 1 specifically includes:

[0015] Step 101: Regulate the first pressure regulating valve to increase the air pressure, so that the gas injection core assembly is in an open state, and carbon dioxide gas passes through the gas injection core assembly and the gas injection hole and enters the inner cavity of the shell; open the second pressure regulating valve to allow carbon dioxide gas to pass through the gas dispersion hole located on the first stirring shaft and enter the inner cavity of the shell;

[0016] Step 102: Start the motor to rotate the first stirring shaft and the second stirring shaft in opposite directions;

[0017] Step 103: The printing material flows into the housing from the feed port of the 3D printing nozzle. Under the cutting and stirring of the first and second stirring shafts, the printing material undergoes a carbonization reaction with the carbon dioxide gas entering the housing from the gas injection holes and the gas dispersion holes. After the carbonization reaction is completed, carbon dioxide gas is continuously introduced into the printing material to form a first carrier layer printing material.

[0018] Step 104: Move the 3D printing nozzle to discharge the first supporting layer printing material prepared in step 103 from the discharge port of the 3D printing nozzle and lay it flat to form the first supporting layer.

[0019] As a preferred example, the step 2 specifically includes:

[0020] Step 201: regulating the first pressure regulating valve to keep the gas injection core assembly in a closed state;

[0021] Step 202: The printing material flows into the housing from the feed port of the 3D printing nozzle. Under the cutting and stirring of the first stirring shaft and the second stirring shaft, the printing material and the carbon dioxide entering the housing from the gas dispersion hole undergo a carbonization reaction to form a pollution-resistant layer printing material.

[0022] Step 203: Move the 3D printing nozzle above the first supporting layer, discharge the anti-fouling layer printing material prepared in step 202 from the outlet of the 3D printing nozzle, and spread it flat on the first supporting layer to form an anti-fouling layer.

[0023] As a preferred example, the step 3 specifically includes:

[0024] Step 301: Regulate the first pressure regulating valve to increase the air pressure, so that the gas injection core assembly is in an open state, and carbon dioxide gas passes through the gas injection core assembly and the gas injection hole and enters the inner cavity of the shell;

[0025] Step 302: The printing material flows into the housing from the feed port of the 3D printing nozzle. Under the cutting and stirring of the first and second stirring shafts, the printing material undergoes a carbonization reaction with the carbon dioxide gas entering the housing from the gas injection holes and the gas dispersion holes. After the carbonization reaction is completed, carbon dioxide gas is continuously introduced into the printing material to form a second carrier layer printing material.

[0026] Step 303: Move the 3D printing nozzle above the anti-fouling layer, discharge the second supporting layer printing material prepared in step 302 from the outlet of the 3D printing nozzle, and spread it on the anti-fouling layer to form the second supporting layer.

[0027] As a preferred example, in step 101, step 201, and step 301, the pressure p of the carbon dioxide gas entering the inner cavity of the shell after adjustment by the first pressure regulating valve is equal to the pressure p of the carbon dioxide gas entering the inner cavity of the shell after adjustment by the second pressure regulating valve; the carbon dioxide gas pressure p is calculated according to formula (1):

[0028] p=p0-a×(f-f0)-b×(R-R0) Formula (1) Wherein, p is the carbon dioxide gas pressure after adjustment by the first pressure regulating valve, in kPa; p0 is the reference pressure, which is 1000, in kPa; a is the adjustment coefficient related to the physical state of the printing material, in kPa / mm; f is the fluidity of the printing material, in mm; f0 is the reference fluidity of the printing material, which is 100, in mm; b is the adjustment coefficient related to the motion state of the first stirring shaft, in kPa / rpm; R is the rotation speed of the first stirring shaft, in rpm; the rotation speed of the first stirring shaft is the same as the rotation speed of the second stirring shaft, and R0 is the reference rotation speed of the first stirring shaft, which is 15, in rpm;

[0029] The total flow rate of carbon dioxide gas flowing through the first pressure regulating valve is equal to the total flow rate of carbon dioxide gas flowing through the second pressure regulating valve. The total flow rate of carbon dioxide gas flowing through the first pressure regulating valve is calculated according to formula (2):

[0030] Q g =10 3 ×c×Q s +10 3 ×d×A×Q s Formula (2)

[0031] Where Q g is the total flow rate of carbon dioxide gas flowing through the first pressure regulating valve, in l / min; c is the adjustment coefficient related to the physical characteristics of the printing material, which is a dimensionless variable; Q s The feeding speed of the printing material, in m 3 / min; d is the adjustment coefficient related to the chemical characteristics of the printing material, which is a dimensionless variable; A is the alkalinity of the printing material, which is the mass ratio of alkaline oxides to acidic oxides in the printing material.

[0032] Compared with the prior art, the 3D printing nozzle and printing method for printing a barrier to contaminated sites of the present invention have significant advantages: (1) It can realize the simultaneous rapid carbonization and printing construction of printing materials, forming a composite barrier with a high sealing effect, and significantly improving the emergency disposal efficiency of sudden soil and groundwater pollution incidents. (2) The 3D printing nozzle includes a shell, a hollow first stirring shaft, a hollow second stirring shaft, a power source and an air source; the shell is provided with an inlet, an outlet and an air injection hole; the second stirring shaft and the shell are connected by a bearing, the second stirring shaft is mounted on the outside of the first stirring shaft, the outer wall of the second stirring shaft is provided with a second stirring blade, the lower outer wall of the first stirring shaft is provided with a first stirring blade, and the lower wall of the first stirring shaft is provided with a gas dispersion hole; the power source drives the first stirring shaft and the second stirring shaft to rotate; the air source is respectively connected to the hollow cavity and the air injection hole of the first stirring shaft. The 3D printing nozzle of this structure provides a tool that can realize the simultaneous rapid carbonization and printing of weakly reactive silicate printing materials represented by cement activated steel slag. (3) The amount of carbon dioxide gas entering the shell cavity is controlled through the gas injection holes and gas dispersion holes, achieving efficient and rapid carbonization and printing construction of the printing material, forming a barrier layer with different performance requirements, and improving the emergency response efficiency of soil and groundwater pollution incidents at sudden sites. (4) In equations (1) and (2), considering the influence of the physical and chemical indicators such as the fluidity and alkalinity of the printing material on the mechanical and barrier properties of the hardened barrier, the input pressure and carbon dioxide injection amount of the printing process are designed, which can achieve a directional design of the service performance parameters of the barrier. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A cross-sectional view of a 3D printing nozzle according to an embodiment of the present invention;

[0034] Figure 2 for Figure 1 A-A' cross section;

[0035] Figure 3 Schematic diagram of the structure of the gas injection hole and the gas injection core in an embodiment of the present invention.

[0036] The figure shows: shell 1, feed port 101, discharge port 102, gas injection hole 103, first pressure regulating valve 1031, connecting valve 1032, first connecting pipe 1033, second connecting pipe 1034, spring 201, sealing piece 202, core 203, fixing part 204, outer shell 205, first stirring shaft 3, gas dispersion hole 301, first stirring blade 4, second stirring shaft 5, second stirring blade 6, first sealing ring 7, second sealing ring 8, gas source 9, third connecting pipe 901, second pressure regulating valve 902, motor 111, power output shaft 1111, first gear 112, second gear 113, protective net 12. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is described in detail below. The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0038] like Figure 1 and Figure 2 As shown, a 3D printing nozzle for printing a barrier to contaminated sites according to an embodiment of the present invention includes a housing 1, a hollow first stirring shaft 3, a hollow second stirring shaft 5, a power source, and a gas source 9. The second stirring shaft 5 is hollow to accommodate the first stirring shaft 3. The first stirring shaft 3 is hollow to transport carbon dioxide gas. The housing 1 is provided with an inlet 101, an outlet 102, and a gas injection hole 103. The second stirring shaft 5 is connected to the housing 1 via a bearing. The outer wall of the second stirring shaft 5 is provided with a second stirring blade 6, which is located within the inner cavity of the housing 1. The second stirring shaft 5 is mounted on the outer side of the first stirring shaft 3. The first and second stirring shafts 3, 5 are connected via a bearing, with a gap between them. The upper portion of the first stirring shaft 3 extends through the top end of the second stirring shaft 5, and the lower portion of the first stirring shaft 3 extends through the bottom end of the second stirring shaft 5. The lower outer wall of the first stirring shaft 3 is provided with a first stirring blade 4, which is located within the inner cavity of the housing 1. The lower wall of the first stirring shaft 3 is provided with a gas dispersion hole 301. The top of the first stirring shaft 3 and the top of the second stirring shaft 5 are respectively connected to a power source, which drives the first stirring shaft 3 and the second stirring shaft 5 to rotate. The air source 9 is respectively connected to the hollow cavity of the first stirring shaft 3 and the air injection hole 103.

[0039] In the 3D printing nozzle of the above embodiment, the printing material enters the inner cavity of the housing 1 through the inlet 101 and then flows out of the housing 1 through the outlet 102. The power source is activated, which drives the first stirring shaft 3 and the second stirring shaft 5 to rotate. This causes the first stirring blade 4 and the second stirring blade 6 to rotate accordingly. The gas source 9 and the gas dispersion hole 301, or the gas dispersion hole 301 and the gas injection hole 103, are activated to inject carbon dioxide gas into the inner cavity of the housing 1. When the printing material is within the inner cavity of the housing 1, the rotation of the first stirring blade 4 and the second stirring blade 6 allows the carbon dioxide gas and the printing material to fully mix and react. By controlling the intake of carbon dioxide gas, the carbon dioxide and the weakly reactive silicates in the printing material are activated and stimulated, thereby enhancing the reactivity of the printing material. Furthermore, carbon dioxide that has not undergone a carbonization reaction can be encapsulated in the printing material, forming tiny bubbles within the printing material, giving the printing material a closed-cell, multi-bubble structure. This reduces the material's mass while maintaining the excellent barrier properties of the barrier, minimizing degradation and damage to the barrier during maintenance and service. By adjusting the gas distribution holes 301 and the gas injection holes 103, the amount of carbon dioxide gas introduced into the inner cavity of the housing 1 can be controlled. Preferably, the gas distribution holes 301 are arranged obliquely downward from the inner cavity of the first stirring shaft 3. This prevents printing material in the housing 1 from entering the gas distribution holes 301 and clogging them.

[0040] Preferably, the feed port 101 is located on the upper side of the housing 1, and the discharge port 102 is located at the bottom of the housing 1; the gas injection hole 103 is a through hole, arranged obliquely upward from the outside to the inside of the housing 1. The feed port 101 is located on the upper side of the housing 1, so that the printing material entering the housing 1 automatically flows downward under the action of gravity. The discharge port 102 is located at the bottom of the housing 1, facilitating the discharge of the printing material from the housing 1. The gas injection hole 103 is a through hole, arranged on the side of the housing 1, so that the carbon dioxide gas entering the inner cavity of the housing 1 through the gas injection hole 103 can flow more evenly to the printing material. The air injection holes 103 are arranged upwardly and obliquely from the outside to the inside of the housing 1, forming an upwardly directed airflow within the inner cavity of the housing 1. Under the cutting action of the first and second stirring blades and the airflow, the printing material undergoes three-dimensional mixing within the inner cavity of the housing 1, providing a larger contact area for the rapid carbonization reaction of silicates and alkaline oxides in the printing material. This can increase the activity of the printing material and effectively reduce the phenomenon of false coagulation caused by localized carbonization. The air injection holes 103 are arranged in multiple layers along the axis of the housing 1; each layer of the first air injection holes has at least three air injection holes 103. The provision of multiple air injection holes 103 can accelerate the injection rate of carbon dioxide into the inner cavity of the housing 1, accelerating the carbonization reaction.

[0041] Preferably, the 3D printing nozzle also includes a first pressure regulating valve 1031, a connecting valve 1032, a first connecting pipe 1033, and a second connecting pipe 1034. Each gas injection hole 103 is provided with a connecting valve 1032. The connecting valves 1032 in the gas injection holes 103 on the same layer are connected via the first connecting pipe 1033, and the first connecting pipes 1033 on different layers are connected via the second connecting pipe 1034. The gas source 9 is connected to the first connecting pipe 1033 or the second connecting pipe 1034 via a fourth connecting pipe, and the first pressure regulating valve 1031 is provided in the fourth connecting pipe. Carbon dioxide gas flowing out of the gas source 9, after pressure adjustment by the first pressure regulating valve 1031, flows into the first connecting pipe 1033 and the second connecting pipe 1034, then flows through the connecting valve 1032 into the gas injection hole 103, and finally flows out of the gas injection hole 103, into the inner cavity of the housing 1, and mixes with the printing material. This structure ensures that the pressure of the carbon dioxide gas flowing out of all gas injection holes 103 is the same. By setting equal pressure, the printing material can be effectively guaranteed to move perpendicularly to the axis of the first stirring shaft 3 and the second stirring shaft 5 in the inner cavity of the housing 1. This prevents the printing material from being quickly discharged from the discharge port 102 due to the pressure difference between the side wall and the center of the inner cavity of the housing 1, thereby reducing the degree of carbonization and homogeneity of the printing material.

[0042] Preferably, Figure 3As shown, a gas injection core assembly is provided in the gas injection hole 103. The gas injection core assembly comprises a fixing member 204, a housing 205, and a spring 201, a sealing plate 202, and a core 203 located within the housing 205. The housing 205 is secured within the inner cavity of the first gas injection hole 1031 via the fixing member 204. One end of the spring 201 is fixedly connected to one end of the housing 205, while the other end of the spring 201 is fixedly connected to the sealing plate 202. The spring 201 exerts a constant compressive force on the sealing plate 202. The core 203 has a hollow through-hole, with both the inlet and outlet ends of the core 203 being open. The sealing plate 202 faces the outlet end of the core 203 and can block the outlet end of the core 203. The inlet end of the core 203 is connected to the connecting valve 1032. The gas injection core assembly is provided to allow carbon dioxide gas to enter the inner cavity of the housing 1 while preventing printing material from flowing into the connecting valve 1032 and causing blockage. When it is necessary to introduce carbon dioxide gas into the inner cavity of the shell 1, carbon dioxide gas flows out from the connecting valve 1032, passes through the inner cavity of the core 203, and uses gas pressure to push the sealing piece 202 away from the gas outlet end of the core 203. The spring 201 is compressed, and a gap is formed between the sealing piece 202 and the gas outlet end of the core 203, allowing the carbon dioxide gas to flow out from the gas outlet end of the core 203, and then out of the outer shell 205 and into the inner cavity of the shell 1. When it is not necessary to introduce carbon dioxide gas into the inner cavity of the shell 1, carbon dioxide gas is not introduced into the connecting valve 1032. Under the action of the spring 201, the sealing piece 202 and the gas outlet end of the core 203 are adapted to each other, which plays the role of sealing the inner cavity of the core 203, thereby preventing the printing material in the shell 1 from flowing into the inner cavity of the core 203 and backflowing into the connecting valve 1032, blocking the carbon dioxide gas flow path.

[0043] Preferably, the power source includes a motor 111 with a power output shaft 1111, a first gear 112, and a second gear 113. The first gear 112 is fixedly connected to the upper outer wall of the first stirring shaft 3, and the second gear 113 is fixedly connected to the upper outer wall of the second stirring shaft 5; the power output shaft 1111 is adapted to the first gear 112 and the second gear 113, respectively, driving the first gear 112 and the second gear 113 to rotate in opposite directions. During operation, the motor 111 is started and the power output shaft 1111 rotates. The first gear 112 and the second gear 113 are adapted to the power output shaft 1111, respectively, and the power output shaft 1111 drives the first gear 112 and the second gear 113 to rotate. Preferably, the first gear 112 is located above the power output shaft 1111, and the second gear 113 is located below the power output shaft 1111, and the first gear 112 and the second gear 113 rotate in opposite directions. In this way, the first stirring blade 4 and the second stirring blade 6 also rotate in opposite directions. By rotating the first stirring blade 4 and the second stirring blade 6 in opposite directions, horizontal cutting and stirring of the printed material can be achieved. At the same time, the oblique cutting effect of the carbon dioxide gas flow in the gas dispersion hole 301 of the shell 1 and the gas injection hole 103 forms a three-dimensional spatial movement, which accelerates the carbonization speed of the printed material and improves the stirring effect.

[0044] Preferably, the 3D printing nozzle also includes a third connecting pipe 901 and a second pressure regulating valve 902. The gas source 9 is connected to the hollow cavity of the first stirring shaft 3 via the third connecting pipe 901, and the second pressure regulating valve 902 is disposed in the third connecting pipe 901. When the gas source 9 is activated, carbon dioxide gas flows into the hollow cavity of the first stirring shaft 3 through the third connecting pipe 901 and then into the inner cavity of the housing 1 through the gas dispersion holes 301. The second pressure regulating valve 902 regulates the air pressure in the third connecting pipe 901, thereby regulating the pressure of the carbon dioxide flowing out of the gas dispersion holes 301.

[0045] Preferably, the 3D printing nozzle also includes a first sealing ring 7 and a second sealing ring 8. The first sealing ring 7 is embedded between the first stirring shaft 3 and the second stirring shaft 5 and is located at the bottom of the inner cavity of the second stirring shaft 5; the second sealing ring 8 is embedded between the second stirring shaft 5 and the housing 1. The first sealing ring 7 prevents printing material in the inner cavity of the housing 1 from entering the gap between the first stirring shaft 3 and the second stirring shaft 5. The second sealing ring 8 prevents printing material in the inner cavity of the housing 1 from flowing out of the housing 1 through the gap between the second stirring shaft 5 and the housing 1.

[0046] Preferably, a protective net 12 is further provided in the gas injection hole 103. The protective net 12 can effectively prevent the printing material in the inner cavity of the housing 1 from entering the gas injection hole 103. At the same time, the protective net 12 is in a mesh shape, which can allow carbon dioxide gas to flow out of the gas injection hole 103 and enter the inner cavity of the housing 1.

[0047] The present invention also provides a method for printing a barrier using the 3D printing nozzle of the above embodiment or preferred example. The barrier comprises, from bottom to top, a first supporting layer, a pollution-blocking layer, and a second supporting layer. The method includes:

[0048] Step 1: Use a 3D printing nozzle to build the first bearing layer;

[0049] Step 2: Using a 3D printing nozzle to build a pollution-resistant layer above the first supporting layer;

[0050] Step 3: Use a 3D printing nozzle to build a second supporting layer above the anti-fouling layer.

[0051] Using the 3D printing nozzles of the above-described embodiments or preferred examples to print barrier barriers allows for rapid and efficient printing, making them suitable for emergency pollution control scenarios. During printing, by controlling the flow of carbon dioxide gas in the 3D printing nozzle, barrier layers with varying performance can be printed. In this embodiment, the barrier barrier comprises, from bottom to top, a first support layer, a pollution barrier layer, and a second support layer. The bottom surface of the first support layer directly contacts the surface of the contaminated site, responsible for bearing the weight of the barrier and subsequent emergency personnel and equipment, while also resisting deformation and damage to the barrier caused by foundation settlement. Therefore, the first support layer requires high strength. The pollution barrier layer, located above the first support layer, is used to prevent the evaporation of polluted gases and has high barrier properties. Therefore, the pollution barrier layer requires minimal open pores. The second support layer, located above the pollution barrier layer, is in direct contact with emergency personnel and equipment, providing considerable buffering capacity against external loads. Therefore, the second support layer requires high strength and the ability to absorb external energy.

[0052] Preferably, in the above printing method, step 1 specifically includes:

[0053] Step 101, regulate the first pressure regulating valve 1031, increase the air pressure, and put the gas injection core assembly into the open state. Use carbon dioxide gas to open the sealing piece 22, and the spring 201 is compressed, so that the gas injection core assembly is in the open state. Carbon dioxide gas passes through the gas injection core assembly and the gas injection hole 103 and enters the inner cavity of the shell 1. Open the second pressure regulating valve 902, so that carbon dioxide gas passes through the gas dispersion hole 301 located on the first stirring shaft 3 and enters the inner cavity of the shell 1. Both the gas injection hole 103 and the gas dispersion hole 301 flow carbon dioxide gas into the inner cavity of the shell 1.

[0054] Step 102 : Start the motor 111 to rotate the first stirring shaft 3 and the second stirring shaft 5 in opposite directions.

[0055] Step 103: The printing material flows into the housing 1 from the feed port 101 of the 3D printing nozzle. Under the cutting and stirring of the first stirring shaft 3 and the second stirring shaft 5, the printing material undergoes a carbonization reaction with the carbon dioxide gas entering the housing 1 from the gas injection hole 103 and the gas dispersion hole 301. The rapid carbonization reaction can form acidic pore water on the surface of the inert silicate particles in the steel slag, triggering the hydrolysis of silicate minerals. At the same time, the carbonization reaction is an exothermic process, and the heat released can promote the phase transformation of silicates in the steel slag. In addition, through the rapid carbonization reaction, the dicalcium silicate, tricalcium silicate and calcium oxide in the steel slag can effectively fix carbon dioxide, forming calcium carbonate crystals, increasing its strength and stability. After the steel slag is carbonized, the calcium carbonate particles fill the internal voids, making the internal arrangement of the system more compact and reducing the porosity. After the carbonization reaction is completed, carbon dioxide gas is continuously introduced into the printing material to form the first supporting layer printing material. After the carbonization reaction is completed, the remaining carbon dioxide gas forms a certain volume of discontinuous closed pores in the hardened printing material, which quickly increases the strength of the first bearing layer of the barrier and significantly reduces the weight of the first bearing layer, reducing the risk of cracking of the barrier in the later stage.

[0056] Step 104 : Move the 3D printing nozzle to discharge the first supporting layer printing material produced in step 103 from the discharge port 102 of the 3D printing nozzle, and spread it flat to form the first supporting layer.

[0057] In step 1, carbon dioxide gas is injected into the inner cavity of the shell 1 through the gas injection holes 103 and the gas dispersion holes 301 to obtain a first bearing layer with required performance.

[0058] After step 1 is completed, preferably, step 2 specifically includes:

[0059] Step 201: Regulate the first pressure regulating valve 1031 to close the gas injection core assembly. By changing the values of a and b in formula (1), the pressure of the carbon dioxide gas regulated by the first pressure regulating valve 1031 is changed. When the pressure of the carbon dioxide gas regulated by the first pressure regulating valve 1031 is less than or equal to the pressure exerted by the spring 201 on the sealing plate 202, the sealing plate 202 and the gas outlet end of the core body 203 touch each other, causing the gas injection core assembly to be closed. The gas injection hole 103 does not inject carbon dioxide gas into the inner cavity of the shell 1.

[0060] In step 202, the printing material flows from the 3D printing nozzle's inlet 101 into the housing 1. Under the action of the first and second stirring shafts 3 and 5, the printing material undergoes a carbonization reaction with the carbon dioxide entering the housing 1 through the gas dispersion holes 301, forming a pollution-blocking layer of printing material. The carbonization reaction increases the reactivity of the inert components in the printing material. After the carbonization reaction is complete, no carbon dioxide gas remains in the printing material, making it denser and effectively enhancing the barrier's ability to intercept pollution.

[0061] Step 203: Move the 3D printing nozzle above the first supporting layer, discharge the anti-fouling layer printing material prepared in step 202 from the discharge port 102 of the 3D printing nozzle, and spread it flat on the first supporting layer to form an anti-fouling layer.

[0062] To improve printing efficiency, the printing end point of the first carrier layer is the printing starting point of the anti-fouling layer.

[0063] After step 2 is completed, preferably, step 3 specifically includes:

[0064] Step 301: Regulate the first pressure regulating valve 1031 to increase the air pressure, opening the gas injection core assembly. Carbon dioxide gas passes through the gas injection core assembly and the gas injection hole 103 and enters the inner cavity of the housing 1. At this time, the second pressure regulating valve 902 is open, and carbon dioxide gas passes through the gas dispersion hole 301 located on the first stirring shaft 3 and enters the inner cavity of the housing 1.

[0065] In step 302, the printing material flows into the housing 1 from the inlet 101 of the 3D printing nozzle. Under the cutting and stirring of the first and second stirring shafts 3 and 5, the printing material undergoes a carbonization reaction with the carbon dioxide gas entering the housing 1 through the gas injection holes 103 and the gas dispersion holes 301. After the carbonization reaction is complete, carbon dioxide gas is continuously introduced into the printing material to form the second carrier layer printing material. Similar to step 102, the carbonization reaction significantly increases the formation of acidic pore water on the surface of the inert silicate particles in the steel slag, initiating the hydrolysis of silicate minerals. Furthermore, the carbonization reaction is an exothermic process, and the heat released can promote the phase transformation of the silicates in the steel slag. Furthermore, the rapid carbonization reaction effectively fixes carbon dioxide in the belcherite, tricalcium silicate, and calcium oxide in the steel slag to form calcium carbonate crystals, increasing its strength and stability. After the steel slag is carbonized, the calcium carbonate particles fill the internal voids, making the system more compact and reducing porosity. After the carbonization reaction is completed, the remaining carbon dioxide gas forms a certain volume of discontinuous closed pores in the hardened printing material, which quickly increases the strength of the second bearing layer of the barrier and significantly reduces the weight of the second bearing layer, reducing the risk of cracking of the barrier in the later stage.

[0066] Step 303: Move the 3D printing nozzle above the anti-fouling layer, discharge the second supporting layer printing material prepared in step 302 from the discharge port 102 of the 3D printing nozzle, and spread it on the anti-fouling layer to form the second supporting layer.

[0067] To improve printing efficiency, the end point of printing the anti-fouling layer is the starting point of printing the second carrier layer.

[0068] In steps 101, 201, and 301, the pressure p of the carbon dioxide gas entering the inner cavity of the housing 1 after adjustment by the first pressure regulating valve 1031 is equal to the pressure p of the carbon dioxide gas entering the inner cavity of the housing 1 after adjustment by the second pressure regulating valve 902. By setting equal pressures, it is possible to effectively ensure that the printing material moves perpendicularly to the axial direction of the first stirring shaft 3 within the inner cavity of the housing 1, avoiding the rapid discharge of the printing material from the discharge port 102 due to the pressure difference between the side wall and the center position of the inner cavity of the housing 1, thereby reducing the carbonization degree and homogeneity of the printing material. The carbon dioxide gas pressure p is calculated according to formula (1):

[0069] p=p0-a×(f-f0)-b×(R-R0) Formula (1) In the formula, p is the carbon dioxide gas pressure after adjustment by the first pressure regulating valve 1031, and the unit is kPa; p0 is the reference pressure, which is 1000 and the unit is kPa; a is the adjustment coefficient related to the physical state of the printing material, and the unit is kPa / mm; f is the fluidity of the printing material, and the unit is mm; f0 is the reference fluidity of the printing material, which is 100 and the unit is mm; b is the adjustment coefficient related to the motion state of the first stirring shaft, and the unit is kPa / rpm; R is the rotation speed of the first stirring shaft 3, and the unit is rpm; the rotation speed of the first stirring shaft 3 is the same as the rotation speed of the second stirring shaft 5, and R0 is the reference rotation speed of the first stirring shaft 3, which is 15 and the unit is rpm.

[0070] The total flow rate of carbon dioxide gas flowing through the first pressure regulating valve 1031 is equal to the total flow rate of carbon dioxide gas flowing through the second pressure regulating valve 902. By setting equal flow rates, it is possible to effectively ensure that the printing material undergoes a uniform carbonization reaction in the inner cavity of the housing 1, reduce the phenomenon of false coagulation of the printing material caused by local carbonization of the printing material, and thus improve the homogeneity of the barrier after hardening and forming. The total flow rate of carbon dioxide gas flowing through the first pressure regulating valve (1031) is calculated according to formula (2):

[0071] Q g =10 3 ×c×Q s +10 3 ×d×A×Q s Formula (2)

[0072] Where Q g is the total flow rate of carbon dioxide gas flowing through the first pressure regulating valve 1031, in l / min; c is the adjustment coefficient related to the physical characteristics of the printing material, which is a dimensionless variable; Q s The feeding speed of the printing material, in m 3 / min; d is the adjustment coefficient related to the chemical characteristics of the printing material, a dimensionless variable; A is the alkalinity of the printing material, which is the mass ratio of alkaline oxides to acidic oxides in the printing material. Alkaline oxides include CaO and MgO. Acidic oxides include SiO2, Al2O3, and Fe2O3.

[0073] By changing the values of a and b, the first pressure regulating valve 1031 is regulated to put the gas injection core assembly in an open state or a closed state. By changing the values of a and b, the pressure of the carbon dioxide gas adjusted by the first pressure regulating valve 1031 is changed. When the pressure of the carbon dioxide gas adjusted by the first pressure regulating valve 1031 is greater than the pressure of the spring 201 on the sealing piece 202, the sealing piece 202 is separated from the air outlet end of the core body 203, so that the gas injection core assembly is in an open state. When the pressure of the carbon dioxide gas adjusted by the first pressure regulating valve 1031 is less than or equal to the pressure of the spring 201 on the sealing piece 202, the sealing piece 202 and the air outlet end of the core body 203 touch each other, so that the gas injection core assembly is in a closed state. Preferably, when the first bearing layer is constructed using a 3D printing nozzle in step 1, the value range of a in formula (1) is: 3-6 kPa / mm; the value range of b is: 5-9 kPa / rpm; the value range of c in formula (2) is: 0.10-0.25; the value range of d is: 0.05-0.15. When the anti-fouling layer is constructed using a 3D printing nozzle in step 2, the value range of a in formula (1) is: 5-8 kPa / mm; the value range of b is: 7-11 kPa / rpm; the value of c in formula (2) is: 0; the value range of d is: 0.05-0.15. In step 3, when the second bearing layer is constructed using a 3D printing nozzle, the value range of a in formula (1) is: 4~7kPa / mm; the value range of b is: 6~10kPa / rpm; the value range of c in formula (2) is: 0.05~0.12; the value range of d is: 0.05~0.15.

[0074] The following is an example of how to calculate the pressure p of the carbon dioxide gas after being regulated by the first pressure regulating valve 1031 and the total flow rate Q of the carbon dioxide gas flowing through the first pressure regulating valve 1031 according to formula (1) and formula (2). g In this embodiment, the alkalinity A of the printing material is 2.60, and the feeding speed Q of the printing material is s Set to 0.03m 3 The reference pressure p0 is 1000 kPa, the reference fluidity f0 of the printing material is 100 mm, and the reference rotation speed R0 of the first stirring shaft is 15 rpm.

[0075] The method for printing a barrier using the 3D printing nozzle of the above embodiment or preferred example includes:

[0076] In step 1, the first supporting layer is constructed using a 3D printing nozzle, the fluidity f of the printing material is set to 180 mm, and the rotation speed R of the first stirring shaft 3 is set to 45 rpm. In formula (1), the value of a is 6 kPa / mm, the value of b is 9 kPa / rpm, the value of c is 0.25, and the value of d is 0.10. Then, the carbon dioxide gas pressure p after adjustment by the first pressure regulating valve 1031 is 1000-6×(180-100)-9×(45-15)=250 kPa, and the total flow rate Q of the carbon dioxide gas flowing through the first pressure regulating valve 1031 is g is 10 3 ×0.25×0.03+10 3 ×0.10×2.60×0.03=15.3l / min.

[0077] Step 2: Use a 3D printing nozzle to build a pollution-blocking layer. Because this layer does not produce gaps in the barrier structure, the fluidity of the printing material and the rotation speed of the first stirring shaft 3 are appropriately reduced. The fluidity f of the printing material is set to 160 mm, and the rotation speed R of the first stirring shaft 3 is set to 40 rpm. In formula (1), the value of a is 5 kPa / mm, the value of b is 7 kPa / rpm, the value of c in formula (2) is 0, and the value of d is 0.05. Then, the carbon dioxide gas pressure p after adjustment by the first pressure regulating valve 1031 is 1000-5×(160-100)-7×(40-15)=525 kPa, and the total flow rate of carbon dioxide gas flowing through the first pressure regulating valve 1031 is Q g is 10 3 ×0×0.03+10 3 ×0.05×2.60×0.03=3.9l / min.

[0078] Step 3: Use the 3D printing nozzle to build the second supporting layer. The fluidity f of the printing material is set to 180 mm, and the rotation speed R of the first stirring shaft 3 is set to 45 rpm. In formula (1), a is set to 4 kPa / mm; b is set to 10 kPa / rpm; c is set to 0.08; and d is set to 0.15. Then, the carbon dioxide gas pressure p after the first pressure regulating valve 1031 is adjusted to 1000-4×(180-100)-10×(45-15)=380 kPa; the total flow rate of carbon dioxide gas flowing through the first pressure regulating valve 1031 is 10 3 ×0.08×0.03+10 3 ×0.15×2.60×0.03=14.1l / min.

[0079] From this embodiment, it can be seen that the barrier printed by the 3D printing nozzle and method of the present invention has a carbon dioxide gas pressure p of 250kPa during the printing of the first carrier layer and a total carbon dioxide flow rate Qg The carbon dioxide gas pressure p during the anti-fouling layer printing process is 525kPa, and the total carbon dioxide flow rate Q g The carbon dioxide gas pressure p during the printing of the second carrier layer is 380kPa, and the total carbon dioxide flow rate Q g By regulating the operating mode of the 3D printing nozzle for printing a contaminated site barrier of the present invention and optimizing the carbon dioxide gas pressure and total carbon dioxide flow rate during the printing process, it is possible to ensure that the barrier has excellent service performance.

[0080] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the specific embodiments described above. The specific embodiments and descriptions in the specification are only intended to further illustrate the principles of the present invention. Various changes and improvements are possible without departing from the spirit and scope of the present invention, and such changes and improvements fall within the scope of the invention as claimed.

Claims

1. A 3D printing nozzle for printing a barrier to contaminated sites, characterized in that: It comprises a shell (1), a hollow first stirring shaft (3), a hollow second stirring shaft (5), a power source and an air source (9); wherein, The shell (1) is provided with an inlet (101), an outlet (102) and an air injection hole (103); The second stirring shaft (5) and the housing (1) are connected via a bearing, and a second stirring blade (6) is provided on the outer wall of the second stirring shaft (5), and the second stirring blade (6) is located in the inner cavity of the housing (1); The second stirring shaft (5) is sleeved on the outside of the first stirring shaft (3), the first stirring shaft (3) and the second stirring shaft (5) are connected via a bearing, and a gap is provided between the first stirring shaft (3) and the second stirring shaft (5); the upper portion of the first stirring shaft (3) passes through the top end of the second stirring shaft (5), and the lower portion of the first stirring shaft (3) passes through the bottom end of the second stirring shaft (5); a first stirring blade (4) is provided on the lower outer wall of the first stirring shaft (3), and the first stirring blade (4) is located in the inner cavity of the shell (1); and a gas dispersion hole (301) is provided on the lower wall of the first stirring shaft (3); The top of the first stirring shaft (3) and the top of the second stirring shaft (5) are respectively connected to a power source, and the power source drives the first stirring shaft (3) and the second stirring shaft (5) to rotate; the air source (9) is respectively connected to the hollow cavity of the first stirring shaft (3) and the air injection hole (103); The feed port (101) is located on the upper side of the shell (1), and the discharge port (102) is located at the bottom of the shell (1); the air injection holes (103) are through holes, arranged obliquely upward from the outside to the inside of the shell (1); the air injection holes (103) are arranged in multiple layers along the axis of the shell (1); at least three air injection holes (103) are provided in each layer of air injection holes; It also includes a first pressure regulating valve (1031), a connecting valve (1032), a first connecting pipe (1033), and a second connecting pipe (1034), wherein: One connecting valve (1032) is provided in each gas injection hole (103); the connecting valves (1032) in the gas injection holes (103) on the same layer are connected via a first connecting pipe (1033); and the first connecting pipes (1033) on different layers are connected via a second connecting pipe (1034); The gas source (9) is connected to the first connecting pipe (1033) or the second connecting pipe (1034) via a fourth connecting pipe, and the first pressure regulating valve (1031) is arranged in the fourth connecting pipe.

2. The 3D printing nozzle for printing a barrier to contaminated sites according to claim 1, characterized in that: An air injection core assembly is provided in the air injection hole (103), and the air injection core assembly comprises a fixing member (204), a shell (205), a spring (201), a sealing sheet (202), and a core body (203) located in the shell (205); the shell (205) is fixed in the inner cavity of the air injection hole (103) via the fixing member (204); one end of the spring (201) is fixedly connected to one end of the shell (205); and the other end of the spring (201) is fixedly connected to the sealing sheet (202); the core body (203) is provided with a hollow through hole, and both the air inlet and air outlet of the core body (203) are open; the sealing sheet (202) and the air outlet of the core body (203) are opposite, and the sealing sheet (202) can block the air outlet of the core body (203); and the air inlet of the core body (203) is connected to the connecting valve (1032).

3. The 3D printing nozzle for printing a barrier to contaminated sites according to claim 2, characterized in that: The power source comprises a motor (111) with a power output shaft (1111), a first gear (112) and a second gear (113), wherein the first gear (112) is fixedly connected to the upper outer wall of the first stirring shaft (3), and the second gear (113) is fixedly connected to the upper outer wall of the second stirring shaft (5); the power output shaft (1111) is respectively adapted to the first gear (112) and the second gear (113), driving the first gear (112) and the second gear (113) to rotate in opposite directions; It also includes a third connecting pipe (901) and a second pressure regulating valve (902), the gas source (9) is connected to the hollow cavity of the first stirring shaft (3) through the third connecting pipe (901), and the second pressure regulating valve (902) is arranged in the third connecting pipe (901); It also includes a first sealing ring (7) and a second sealing ring (8), wherein the first sealing ring (7) is embedded between the first stirring shaft (3) and the second stirring shaft (5) and is located at the bottom of the inner cavity of the second stirring shaft (5); and the second sealing ring (8) is embedded between the second stirring shaft (5) and the housing (1).

4. A method for printing a barrier using the 3D printing nozzle according to claim 3, characterized in that: The barrier comprises, from bottom to top, a first supporting layer, a pollution-blocking layer, and a second supporting layer; the method comprises: Step 1: Use a 3D printing nozzle to build the first bearing layer; Step 2: Using a 3D printing nozzle to build a pollution-resistant layer above the first supporting layer; Step 3: Use a 3D printing nozzle to build a second supporting layer above the anti-fouling layer.

5. The method for printing a barrier according to claim 4, characterized in that: The step 1 specifically includes: Step 101: regulating the first pressure regulating valve (1031) to increase the air pressure so that the gas injection core assembly is in an open state, and the carbon dioxide gas passes through the gas injection core assembly and the gas injection hole (103) and enters the inner cavity of the shell (1); Opening the second pressure regulating valve (902) allows the carbon dioxide gas to pass through the gas dispersion hole (301) located on the first stirring shaft (3) and enter the inner cavity of the shell (1); Step 102: Start the motor (111) to rotate the first stirring shaft (3) and the second stirring shaft (5) in opposite directions; Step 103: The printing material flows into the housing (1) from the feed port (101) of the 3D printing nozzle. Under the cutting and stirring of the first stirring shaft (3) and the second stirring shaft (5), the printing material undergoes a carbonization reaction with the carbon dioxide gas entering the housing (1) from the gas injection hole (103) and the gas dispersion hole (301). After the carbonization reaction is completed, the carbon dioxide gas is continuously introduced into the printing material to form a first carrier layer printing material. Step 104: Move the 3D printing nozzle to discharge the first supporting layer printing material produced in step 103 from the discharge port (102) of the 3D printing nozzle and spread it flat to form the first supporting layer.

6. The method for printing a barrier according to claim 5, characterized in that: The step 2 specifically includes: Step 201: regulating the first pressure regulating valve (1031) to keep the gas injection core assembly in a closed state; Step 202: The printing material flows into the housing (1) from the feed port (101) of the 3D printing nozzle. Under the cutting and stirring of the first stirring shaft (3) and the second stirring shaft (5), the printing material and the carbon dioxide entering the housing (1) from the gas dispersion hole (301) undergo a carbonization reaction to produce a pollution-proof layer printing material. Step 203: above the first supporting layer, move the 3D printing nozzle, discharge the anti-fouling layer printing material prepared in step 202 from the discharge port (102) of the 3D printing nozzle, and spread it flat on the first supporting layer to form an anti-fouling layer.

7. The method for printing a barrier according to claim 6, characterized in that: The step 3 specifically includes: Step 301: regulating the first pressure regulating valve (1031) to increase the air pressure, so that the gas injection core assembly is in an open state, and the carbon dioxide gas passes through the gas injection core assembly and the gas injection hole (103) and enters the inner cavity of the shell (1); Step 302: The printing material flows into the housing (1) from the feed port (101) of the 3D printing nozzle. Under the cutting and stirring of the first stirring shaft (3) and the second stirring shaft (5), the printing material undergoes a carbonization reaction with the carbon dioxide gas entering the housing (1) from the gas injection hole (103) and the gas dispersion hole (301). After the carbonization reaction is completed, the carbon dioxide gas is continuously introduced into the printing material to form a second carrier layer printing material. Step 303: above the anti-fouling layer, move the 3D printing nozzle, discharge the second supporting layer printing material prepared in step 302 from the discharge port (102) of the 3D printing nozzle, and spread it on the anti-fouling layer to form the second supporting layer.

8. The method for printing a barrier according to claim 7, wherein: In the steps 101, 201 and 301, the first pressure regulating valve (1031) regulates the pressure of the carbon dioxide gas entering the inner cavity of the housing (1). p , and the pressure of the carbon dioxide gas entering the inner cavity of the shell (1) after being regulated by the second pressure regulating valve (902) p Equal; Calculate the carbon dioxide gas pressure according to formula (1) p : Formula (1) Where, p is the pressure of carbon dioxide gas after being adjusted by the first pressure regulating valve (1031), in kPa; p 0 is the reference pressure, with a value of 1000, in kPa; a is the adjustment factor related to the physical state of the printing material, the unit is kPa / mm; f The fluidity of the printing material, in mm; f 0 is the base fluidity of the printing material, which is 100 and the unit is mm; b is the adjustment coefficient related to the motion state of the first stirring shaft, the unit is kPa / rpm; R is the rotation speed of the first stirring shaft (3), in rpm; the rotation speed of the first stirring shaft (3) is the same as the rotation speed of the second stirring shaft (5), R 0 is the reference rotation speed of the first stirring shaft (3), which is 15 and is expressed in rpm; The total flow rate of carbon dioxide gas flowing through the first pressure regulating valve (1031) is equal to the total flow rate of carbon dioxide gas flowing through the second pressure regulating valve (902). The total flow rate of carbon dioxide gas flowing through the first pressure regulating valve (1031) is calculated according to formula (2): Formula (2) Where, Q g is the total flow rate of carbon dioxide gas flowing through the first pressure regulating valve (1031), in l / min; c is the adjustment coefficient related to the physical characteristics of the printing material and is a dimensionless variable; Q s The feeding speed of the printing material, in units of ; d is the adjustment coefficient related to the chemical characteristics of the printing material and is a dimensionless variable; A is the alkalinity of the printing material, which is the mass ratio of alkaline oxides to acidic oxides in the printing material.

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