Printing nozzle suitable for 3D printing of ammonium magnesium phosphate cement

Abstract

The invention provides a printing spray head suitable for 3D printing of ammonium magnesium phosphate cement. The printing spray head comprises a spray head outer cylinder, a spray head inner cylinder, a nozzle, a feeding pipe, a bidirectional rotating motor, a rotating rod and a plurality of inclined mixing blades. A nozzle is arranged below the nozzle outer cylinder, the nozzle inner cylinder is arranged in the nozzle outer cylinder, a gap is reserved between the side wall of the nozzle inner cylinder and the side wall of the nozzle outer cylinder and communicated with the nozzle, an opening is formed in the top of the nozzle inner cylinder and communicated with the nozzle outer cylinder, and a movable baffle is arranged at the bottom of the nozzle inner cylinder. The bidirectional rotating motor is arranged above the nozzle inner cylinder, one end of the rotating rod is fixedly connected with a rotating output shaft of the bidirectional rotating motor, the other end of the rotating rod is rotationally connected with the movable baffle, and the inclined mixing blades are arranged on the rotating rod at equal intervals from the upper end to the lower end of the nozzle inner cylinder.

Description

Technical Field

[0001] The present invention relates to a 3D printing technology, in particular to a printing nozzle suitable for 3D printing of magnesium ammonium phosphate cement. Background Art

[0002] 3D printing technology, also known as additive manufacturing, is a new manufacturing technology. Compared with traditional manufacturing technologies, its most prominent feature is its close combination with digital models. Through the printer nozzle, according to the printing path generated based on the digital model, materials (such as cement) are extruded and stacked layer by layer to form a three-dimensional entity.

[0003] Magnesium ammonium phosphate cement is more suitable for the application of 3D printing technology based on its characteristics of rapid hardening and early strength, and can achieve the purpose of rapid prototyping of three-dimensional entities. However, compared with conventional portland cement, the characteristics of rapid hardening and early strength of magnesium ammonium phosphate cement will also cause its cement slurry to not be able to stay in the mixing container for a long time, and it is extremely easy to solidify in the mixing container or the conveying pipe, resulting in the obstruction of the construction progress, and at the same time causing greater economic losses. Moreover, during the curing process of the magnesium ammonium phosphate cement slurry, a certain amount of toxic ammonia gas will be released. Summary of the Invention

[0004] The purpose of the present invention is to provide a printing nozzle suitable for 3D printing of magnesium ammonium phosphate cement, including a nozzle outer cylinder, a nozzle inner cylinder, a nozzle, a feed pipe, a bidirectional rotation motor, a rotating rod, and a number of inclined mixing blades; wherein a nozzle is provided below the nozzle outer cylinder, the nozzle inner cylinder is arranged inside the nozzle outer cylinder, there is a gap between the side wall of the nozzle inner cylinder and the side wall of the nozzle outer cylinder, and the gap is communicated with the nozzle. An opening is provided at the top of the nozzle inner cylinder to communicate with the nozzle outer cylinder, and a movable baffle is provided at the bottom of the nozzle inner cylinder. The outlet of the feed pipe is arranged at the bottom of the nozzle inner cylinder. The bidirectional rotation motor is arranged above the nozzle inner cylinder. One end of the rotating rod is fixedly connected to the rotating output shaft of the bidirectional rotation motor and the other end is rotatably connected to the movable baffle. The inclined mixing blades are arranged on the rotating rod at equal distances from the upper end to the lower end of the nozzle inner cylinder. When the bidirectional rotation motor rotates forward, the inclined mixing blades will bring the mixed magnesium ammonium phosphate cement from the bottom of the nozzle inner cylinder to the top and fall into the gap between the nozzle inner cylinder and the side wall of the nozzle outer cylinder.

[0005] Further, the lower part of the nozzle outer cylinder is in a hollow frustum shape, and the nozzle is provided on the lower bottom surface of the frustum shape.

[0006] Further, it also includes a rotating head and a number of flat mixing blades; wherein The rotating head is frustum-shaped and arranged in the frustum-shaped cavity of the nozzle outer cylinder, The rotating rod passes through the movable baffle and is fixedly connected to the rotating table, The flat mixing blades are arranged on the side wall of the rotating head.

[0007] Furthermore, the movable baffle is detachably connected to the inner cylinder of the nozzle.

[0008] Furthermore, it further includes a rotary handle, a driving rod, and a limiting rod. The driving rod is fixed to the side wall of the movable baffle, and the limiting rod is fixed to the side wall of the movable baffle and is located on one side of the driving rod. The driving rod and the limiting rod pass through the side wall of the outer cylinder of the nozzle and are fixedly connected to the rotary handle. When the rotary handle abuts against the limiting rod, the movable baffle is connected to the inner cylinder of the nozzle.

[0009] Furthermore, it further includes an air suction port, an exhaust duct, an eccentric wheel, a swing rod, and a follower bracket. The eccentric wheel is arranged on the output shaft of the bidirectional rotary motor. A strip-shaped reserved groove is arranged at the upper end of the swing rod, and the strip-shaped reserved groove is slidably connected to the eccentric shaft of the eccentric wheel. The upper end of the follower bracket is arranged on the swing rod, the air suction port is arranged on the cross plate at the lower end of the follower bracket, and one end of the exhaust duct is communicated with the air suction port and the other end is connected to the input end of the air pump.

[0010] By providing the outer cylinder of the nozzle, the inner cylinder of the nozzle, and the slurry mixing mechanism, the invention can instantaneously mix the magnesium ammonium phosphate cement slurry inside the inner cylinder of the nozzle when in use, achieving the purpose of mixing immediately upon use, avoiding the problem of slurry curing and damaging the mixing container caused by pre-mixing of the magnesium ammonium phosphate slurry, improving the construction speed, avoiding delays in the construction progress, and achieving efficient mixing through upward stirring. Moreover, through the exhaust gas absorption mechanism, it can adsorb the toxic ammonia gas generated during the curing process of the magnesium ammonium phosphate cement slurry to a certain extent, achieving the purpose of reducing the harm caused by the magnesium ammonium phosphate cement slurry to construction workers and users.

[0011] The present invention will be further described below in conjunction with the accompanying drawings of the specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a front view schematic diagram of the three-dimensional structure of the present invention.

[0013] Figure 2 It is a side view schematic diagram of the three-dimensional structure of the present invention.

[0014] Figure 3 It is a cross-sectional view schematic diagram of the three-dimensional structure of the present invention.

[0015] Figure 4 It is a partial schematic diagram of the three-dimensional structure of the present invention.

[0016] Figure 5 For the present invention Figure 3 The enlarged schematic diagram of the structure at position A.

[0017] Figure 6 For the present invention Figure 3 The enlarged schematic diagram of the structure at position B.

[0018] Figure 7 This is a schematic diagram of the open state of the slag removal mechanism of the present invention.

[0019] Figure 8 For the present invention Figure 4 An enlarged schematic diagram of the structure at position C in it.

[0020] Figure 9 For the present invention Figure 4 An enlarged schematic diagram of the structure at position D in it.

[0021] In the figure: 1, outer nozzle cylinder; 2, inner nozzle cylinder; 3, square nozzle; 4, feed pipe; 5, support frame; 6, bidirectional rotation motor; 7, rotating rod; 8, inclined mixing blade; 9, rotating head; 10, flat mixing blade; 11, eccentric runner; 12, follower bracket; 13, swing rod; 14, air suction port; 15, exhaust duct; 16, movable baffle; 17, drive rod; 18, rotating handle; 19, limiting rod; 20, limiting groove. Specific embodiments

[0022] Combined with Figure 1 , Figure 2 , a printing nozzle applicable to the 3D printing of magnesium ammonium phosphate cement, comprising an outer nozzle cylinder 1, an inner nozzle cylinder 2, a nozzle 3, a feed pipe 4, a bidirectional rotation motor 6, a rotating rod 7, and an inclined mixing blade 8. The outer nozzle cylinder 1 is supported and fixed by a support frame 5; the inner nozzle cylinder 2 is arranged inside the outer nozzle cylinder 1, the upper part of the inner nozzle cylinder 2 is open and the bottom is closed, and the gap formed between the inner nozzle cylinder 2 and the outer nozzle cylinder 1 is a channel for the flow of magnesium ammonium phosphate cement; the nozzle 3 is arranged at the lower end of the outer nozzle cylinder 1 and is communicated with the channel for the flow of magnesium ammonium phosphate cement; the discharge port of the feed pipe 4 is arranged at the bottom of the inner nozzle cylinder 2, and the feed port 4 of the feed port is connected to the base material distribution end required for the mixing of the magnesium ammonium phosphate cement slurry; the bidirectional rotation motor 6 is arranged above the inner nozzle cylinder 2, and its rotating output shaft is fixedly connected to the upper end of the rotating rod 7; a plurality of inclined mixing blades 8 are arranged axially on the rotating rod 7, and the inclined mixing blades 8 are arranged from the top of the inner nozzle cylinder 2 along the rotating rod 7 to the bottom of the inner nozzle cylinder 2. The inclined mixing blades 8 mix the base material required for the mixing of the magnesium ammonium phosphate cement slurry and transport it from the bottom of the inner nozzle cylinder 2 to the top and then fall into the channel between the inner nozzle cylinder 2 and the outer nozzle cylinder 1, and are ejected from the nozzle 3 by gravity.

[0023] The base materials required for mixing the specific ammonium magnesium phosphate cement slurry are ammonium magnesium phosphate cement clinker, mixing water, and a retarder used for mixing ammonium magnesium phosphate cement. The commonly used retarder components are borax, boric acid, and sodium tripolyphosphate, which can effectively delay the setting speed of ammonium magnesium phosphate cement and improve its workability. The specific ingredient ratios of ammonium magnesium phosphate cement clinker, mixing water, and the retarder used for mixing ammonium magnesium phosphate cement can be formulated according to the actual construction situation. The basic requirement is that the slurry discharged through the square nozzle 3 will basically not collapse by itself and is in a quasi-solid state. Based on this, the feed pipe 4 includes 3 branches, which are respectively used to transport ammonium magnesium phosphate cement clinker, water, and retarder.

[0024] The upper part of the outer cylinder 1 of the nozzle is cylindrical, and the lower part is trapezoidal, with a hollow inside the trapezoid. The upper edge height of the inner cylinder 2 of the nozzle is slightly lower than the upper edge height of the outer cylinder 1 of the nozzle. Combined Figure 3 , a hook is provided at the upper end of the support frame 5 for convenient suspension of the printing nozzle. The lower bottom plate of the support frame 5 covers the upper opening of the outer cylinder 5 of the nozzle and is sealed with sealant. A bidirectional rotation motor 6 is provided on the lower bottom plate of the support frame 5. The rotation output shaft of the bidirectional rotation motor 6 passes through the lower bottom plate and is fixedly connected to the rotating rod 7, and the rotation output shaft is sealed with the lower bottom plate. The feed inlet of the feed pipe 4 is arranged above the outer cylinder 1 of the nozzle and passes through the outer cylinder 1 of the nozzle into the channel between the outer cylinder 1 of the nozzle and the inner cylinder 1 of the nozzle and extends downward to the bottom of the inner cylinder 2 of the nozzle and then passes through the side wall of the inner cylinder 2 of the nozzle into the inner cylinder 2 of the nozzle. The feed pipe 4 is sealed with the outer cylinder 1 of the nozzle and the inner cylinder 2 of the nozzle.

[0025] Combined Figure 3 , Figure 4 , obliquely arranged mixing blades 8 are fixedly connected to the outer surface of the rotating rod 7 at equal distances. When the bidirectional rotation motor 6 rotates forward, the obliquely arranged mixing blades 8 drive the cement mixture at the bottom of the inner cylinder 2 of the nozzle upward; when the bidirectional rotation motor 6 rotates reversely, the obliquely arranged mixing blades 8 stir the mixture in the inner cylinder 2 of the nozzle to fully blend.

[0026] Combined Figure 3 , Figure 4 , Figure 5 , flat mixing blades 10 are fixedly connected to the outer surface of the rotating head 9 in a circumferential array. The rotating rod 7 passes through the bottom of the inner cylinder 2 of the nozzle and is fixedly connected to the rotating head 9, and the rotating rod 7 is sealed with the inner cylinder 2 of the nozzle. The rotating head 9 is trapezoidal, matching the lower trapezoid of the outer cylinder 1 of the nozzle and having a gap therebetween.

[0027] When the bidirectional rotating motor 6 rotates, the rotating head 9 is driven to rotate by the rotating rod 7, and at the same time, the inclined mixing blades 8 and the flat mixing blades 10 are driven to rotate respectively below the inner cylinder 2 of the nozzle and the outer cylinder 1 of the nozzle. First, after the base material enters the lower part of the inner cylinder 2 of the nozzle through the feed pipe 4, it is first mixed for the first time by the inclined mixing blades 8. Since the outlet of the inner cylinder 2 of the nozzle is above, the ammonium magnesium phosphate cement slurry after convergence will gradually move upward when the rotating rod 7 rotates counterclockwise. Restricted by the gravity of the slurry, it tends to move downward below the inner cylinder 2 of the nozzle, but driven forcefully by the inclined mixing blades 8, it will gradually move upward and enter the gap between the outer cylinder 1 of the nozzle and the inner cylinder 2 of the nozzle through the upper outlet of the inner cylinder 2 of the nozzle. This process makes the mixing time of the slurry longer and more uniform. After the slurry enters the lower part of the outer cylinder 1 of the nozzle, it is subjected to parallel separation and remixing by the flat mixing blades 10, further improving the mixing efficiency of the slurry, and then is discharged onto the target path through the square nozzle 3.

[0028] Combined with Figure 6 、 Figure 7 The inner cylinder 2 of the nozzle includes a cylindrical barrel body and a movable baffle 16 below. The movable baffle 16 is detachably connected to the barrel body. Specifically, the movable baffle 16 is connected to the barrel body 2 by a keyway and is sealed. Driving rods 17 and limiting rods 19 are arranged on the side wall of the movable baffle 16. The driving rods 17 and the limiting rods 19 pass through the side wall of the outer cylinder 1 of the nozzle. A rotating handle 18 is arranged at the end of the driving rod 17 outside the outer cylinder 1 of the nozzle; a limiting groove 20 is arranged on the outer wall of the outer cylinder 1 of the nozzle, and the limiting groove 20 limits the rotating handle 18; when the rotating handle 18 is disengaged from the limit of the limiting groove 20, the rotating handle 18 is pulled, so that the movable baffle 16 is separated from the barrel body of the inner cylinder 2 of the nozzle; when the rotating handle 18 is pushed and abuts against the limiting rod 19, the movable baffle 16 just connects with the barrel body of the inner cylinder 2 of the nozzle to realize the sealing of the bottom of the inner cylinder 2 of the nozzle.

[0029] After the device is used up and flushed, when flushing the device, only the feed pipe 4 is used to supply water to the inside of the device. However, limited by the outlet position of the inner cylinder 2 of the nozzle, slurry residues with a specific gravity greater than that of water will gradually accumulate inside the inner cylinder 2 of the nozzle. At this time, the rotating handle 18 is slightly rotated. After the limiting groove 20 releases the limit on the rotating handle 18, the rotating handle 18 is pulled to separate the movable baffle 16 from the inner cylinder 2 of the nozzle, realizing the lower opening of the inner cylinder 2 of the nozzle, and continuous water is passed through the feed pipe 4 for flushing. The slurry residues will directly enter the gap between the outer cylinder 1 of the nozzle and the inner cylinder 2 of the nozzle through the reserved groove below the inner cylinder 2 of the nozzle and be discharged through the square nozzle 3.

[0030] Combined with Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 、 Figure 8 、 Figure 9, an exhaust gas absorption mechanism for adsorbing the exhaust gas generated during cement mixing is provided on the outer surface of the outer cylinder 1 of the nozzle. The exhaust gas absorption mechanism includes an air suction port 14, an exhaust duct 15, an eccentric wheel 11 fixedly connected to the upper output shaft of the bidirectional rotation motor 6, and a swing rod 12 rotatably connected to the side surfaces of the outer cylinder 1 of the nozzle and the support frame 5. At the same time, the eccentric part of the eccentric wheel 11 slides inside the strip-shaped reserved groove at the upper part of the swing rod 12, and the lower end of the swing rod 12 is detachably connected with a follower bracket 13.

[0031] The air suction port 14 is communicated with the exhaust duct 15, and the air suction port 14 is installed on the cross plate of the follower bracket 13. At the same time, the exhaust duct 15 is fixedly connected to the vertical rod of the follower bracket 13. The exhaust duct 15 needs to be communicated with an external exhaust gas treatment or discharge structure, specifically an external air pump. The exhaust duct 15 is connected to the input end of the air pump, and the output end of the air pump is connected to the exhaust gas treatment device or extended to an open area. When the bidirectional rotation motor 6 rotates, the eccentric wheel 11 above it will drive the swing rod 12 to swing reciprocally, thereby driving the follower bracket 13 and the air suction port 14 to swing reciprocally, improving the absorption efficiency of the exhaust gas.

[0032] Combined Figure 9 , the purpose of setting the swing rod 12 and the follower bracket 13 to be detachable is to facilitate the disassembly of the exhaust gas absorption mechanism when the nozzle moves to a relatively narrow position, avoiding the nozzle being unable to move in special positions. Based on the need for 3D printing technology to be stacked multiple times along a fixed path to achieve the purpose of 3D printing, that is, the exhaust gas absorption mechanism will pass above the discharged magnesium ammonium phosphate cement slurry multiple times. Based on the fact that the density of ammonia is less than that of air, ammonia will be in a gradually rising state. The exhaust gas absorption mechanism passing above it can adsorb the exhaust gas multiple times, thereby achieving the effects of exhaust gas absorption and centralized discharge.

[0033] Based on the hydration reaction of magnesium ammonium phosphate cement slurry, a large amount of heat will be released, that is, the entire nozzle needs to be cast with high-temperature resistant materials to avoid the situation of high-temperature deformation after long-term use of the nozzle.

[0034] The working principle of the present invention is as follows: Connect the feed pipe 4 with the conveying pipes of magnesium ammonium phosphate cement clinker, mixing water, and the retarder used for mixing magnesium ammonium phosphate cement. Then, convey the materials inside the inner nozzle barrel 2 in accordance with a pre-set ratio, and start the bidirectional rotation motor 6. When the bidirectional rotation motor 6 rotates, it will drive the rotating rod 7, the rotating head 9, the inclined mixing blades 8, and the flat mixing blades 10 to rotate counterclockwise. At this time, the slurry inside the inner nozzle barrel 2 gradually increases, and after being evenly stirred and mixed, it enters the gap between the outer nozzle barrel 1 and the inner nozzle barrel 2, and is laid on the predetermined path through the square nozzle 3, realizing the on-demand mixing without pre-mixing the magnesium ammonium phosphate cement slurry, avoiding the risk that the pre-mixed magnesium ammonium phosphate cement slurry solidifies in the mixing container due to special circumstances, improving the construction efficiency and reducing economic losses. When the bidirectional rotation motor 6 rotates, it will also drive the swing rod 12 to reciprocate through the eccentric wheel 11, and drive the detachable follower bracket 13 and the air suction port 14 to adsorb the toxic ammonia gas on the path, reducing the physical harm of the toxic gas to the construction workers and users. When it is necessary to rinse the nozzle, first inject water into the nozzle internally through the feed pipe 4 alone. After rinsing for a certain period of time, rotate and pull the rotating handle 18 to open the reserved hole on the inner nozzle barrel 2 blocked by the movable baffle 16. After the residual slag inside the inner nozzle barrel 2 is discharged, rotate and reset the rotating handle 18 to close the lower reserved opening of the inner nozzle barrel 2 by the movable baffle 16 again.

Claims

1. A printing nozzle applicable to 3D printing of magnesium ammonium phosphate cement, characterized in that, It includes an outer nozzle cylinder (1), an inner nozzle cylinder (2), a nozzle (3), a feed pipe (4), a bidirectional rotating motor (6), a rotating rod (7), and several inclined mixing vanes (8); among them The nozzle (3) is arranged below the outer nozzle cylinder (1). The inner nozzle cylinder (2) is arranged inside the outer nozzle cylinder (1). There is a gap between the side wall of the inner nozzle cylinder (2) and the side wall of the outer nozzle cylinder (1), and the gap communicates with the nozzle (3). The top of the inner nozzle cylinder (2) is provided with an opening that communicates with the outer nozzle cylinder (1). An activity baffle (16) is arranged at the bottom of the inner nozzle cylinder (2). The discharge port of the feed pipe (4) is arranged at the bottom of the inner nozzle cylinder (2). The bidirectional rotating motor (6) is arranged above the inner nozzle cylinder (2). One end of the rotating rod (7) is fixedly connected to the rotating output shaft of the bidirectional rotating motor (6), and the other end is rotatably connected to the activity baffle (16). The inclined mixing vanes (8) are arranged on the rotating rod (7) at equal distances from the upper end to the lower end of the inner nozzle cylinder (2). When the bidirectional rotating motor (6) rotates forward, the inclined mixing vanes (8) bring the mixed magnesium ammonium phosphate cement from the bottom of the inner nozzle cylinder (2) to the top and fall into the gap between the inner nozzle cylinder (2) and the side wall of the outer nozzle cylinder (1).

2. The print head according to claim 1, wherein, The lower part of the outer nozzle cylinder (1) is in the shape of a hollow frustum, and the nozzle (3) is arranged on the lower bottom surface of the frustum.

3. The print head according to claim 2, characterized in that, It also includes a rotating head (9) and several flat mixing vanes (10); among them The rotating head (9) is frustum-shaped and is arranged in the frustum-shaped cavity of the outer nozzle cylinder (1). The rotating rod (7) passes through the activity baffle (16) and is fixedly connected to the rotating table (9). The flat mixing vanes (10) are arranged on the side wall of the rotating head (9).

4. The print head according to claim 1, characterized in that, The activity baffle (16) is detachably connected to the barrel of the inner nozzle cylinder (2).

5. The print head according to claim 4, characterized in that, It also includes a rotating handle (18), a driving rod (17), and a limiting rod (19), among which The driving rod (17) is fixed to the side wall of the activity baffle (16). The limiting rod (19) is fixed to the side wall of the activity baffle (16) and is located on one side of the driving rod (17). The driving rod (17) and the limiting rod (19) pass through the side wall of the outer nozzle cylinder (1) and are fixedly connected to the rotating handle (18). When the rotating handle (18) abuts against the limiting rod (19), the activity baffle (16) is connected to the barrel of the inner nozzle cylinder (2).

6. The print head according to claim 1, characterized in that, It also includes an air suction port (14), an exhaust duct (15), an eccentric wheel (11), a swing rod (12), and a follower bracket (13), among which The eccentric wheel (11) is arranged on the output shaft of the bidirectional rotating motor (6). A strip-shaped reserved groove is arranged at the upper end of the swing rod (12), and the strip-shaped reserved groove is slidably connected to the eccentric shaft of the eccentric wheel (11). The upper end of the follower bracket (13) is arranged on the swing rod (12). The air suction port (14) is arranged on the horizontal plate at the lower end of the follower bracket (13). One end of the exhaust duct (15) communicates with the air suction port (14), and the other end is connected to the input end of the air pump.

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