Spiral lap joint device and mixing plant

Abstract

The utility model provides a spiral lap joint device and a mixing plant, and belongs to the field of engineering machinery. The screw lap joint device comprises a main screw conveyor and a lap joint screw conveyor and is used for conveying materials in a powder bin, a feeding port of the main screw conveyor receives the materials and outputs the materials from a first discharging port of the main screw conveyor, the lap joint screw conveyor is connected with the main screw conveyor, a feeding port of the lap joint screw conveyor receives the materials, and the lap joint screw conveyor outputs the materials from a second discharging port of the main screw conveyor. And the spiral conveying amount of the lap joint screw conveyor is smaller than or equal to that of the main screw conveyor. By arranging the main screw conveyor and the lap joint screw conveyor, the conveying capacity of the lap joint screw conveyor is smaller than that of the main screw conveyor, and the functions of balancing conveying force, reducing pipe blockage and improving productivity are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of engineering machinery, in particular to a spiral overlapping device and a mixing station. Background Art

[0002] In the process of large-scale construction, mixing stations are mostly arranged with double rows of multiple powder silos. Between the double rows of multiple powder silos, screw conveyors are mainly used to transport the required materials.

[0003] However, the screw conveyor has an unbalanced conveying force during the material conveying process, which is prone to pipe blockage accidents. Utility Model Content

[0004] The utility model provides a spiral overlapping device and a mixing station, which are used to solve the defect of pipe blocking caused by unbalanced spiral conveying force in the prior art and reduce the occurrence of pipe blocking.

[0005] The utility model provides a spiral overlap device, which is used for overlapping more than two rows of powder bins in a mixing station, and comprises an overlap screw machine and a main screw machine, wherein the feed port of the overlap screw machine is used to connect the discharge port of the rear row powder bin, the first feed port of the main screw machine is used to connect the discharge port of the front row powder bin, the discharge port of the overlap screw machine is connected to the second feed port of the main screw machine, and the first discharge port of the main screw machine is used to connect the mixer;

[0006] A first motor is provided near the feed inlet of the overlapping screw machine, and the first motor is connected to the overlapping screw machine through a first reducer. A second motor is provided near the second feed inlet of the main screw machine, and the second motor is connected to the main screw machine through a second reducer.

[0007] The screw conveying capacity of the overlapping screw machine is less than or equal to the screw conveying capacity of the main screw machine.

[0008] Optionally, the speed ratio of the first reducer is less than or equal to the speed ratio of the second reducer, and the diameter of the spiral outer tube of the overlapping screw machine is smaller than the diameter of the spiral outer tube of the main screw machine.

[0009] Optionally, the overlapping screw machine is a 219 screw machine, the speed ratio of the first reducer is 1:7 or 1:10, the main screw machine is a 273 screw machine, and the speed ratio of the second reducer is 1:7.

[0010] Optionally, the speed ratio of the first reducer is smaller than the speed ratio of the second reducer, and the diameter of the spiral outer tube of the overlapping screw machine is the same as the diameter of the spiral outer tube of the main screw machine.

[0011] Optionally, both the main screw machine and the overlapping screw machine are 273 screw machines, the speed ratio of the second reducer is 1:7, and the speed ratio of the first reducer is 1:10.

[0012] The utility model provides a mixing station, comprising a spiral overlapping device, a powder bin and a mixer, wherein the powder bin comprises more than two rows of powder bins, two adjacent rows of powder bins are overlapped by the spiral overlapping device, and the spiral overlapping device transfers the materials in the powder bin to the powder material measuring hopper of the mixing station.

[0013] Optionally, the powder bin is a double-row powder bin, which includes a first rear-row powder bin and a first front-row powder bin, a first discharge cylinder is provided at the discharge port of the first rear-row powder bin, a first manual butterfly valve is installed on the first discharge cylinder, and a second discharge cylinder is provided at the discharge port of the first front-row powder bin, a second manual butterfly valve is installed on the second discharge cylinder;

[0014] A first feed hopper is provided at the feed inlet of the overlapping screw machine, a second feed hopper is provided at the first feed inlet of the main screw machine, a first discharge cylinder is connected to the first feed hopper, and a second discharge cylinder is connected to the second feed hopper;

[0015] The discharge port of the overlapping screw machine is provided with an overlapping discharge barrel, and the second feed port of the main screw machine is provided with an overlapping feed barrel, and the material can be transported from the overlapping discharge barrel to the overlapping feed barrel;

[0016] The mixer is provided with a powder measuring hopper for rough and fine weighing of materials. A discharge barrel is provided at the first discharge port of the main screw machine. The discharge barrel is connected to the feed port of the powder measuring hopper, and the material can enter the powder measuring hopper through the discharge barrel.

[0017] Optionally, the diameter of the spiral outer tube of the overlapping screw machine is the same as the diameter of the spiral outer tube of the main screw machine, the speed ratio of the first reducer is smaller than the speed ratio of the second reducer, and the unloading area of ​​the first manual butterfly valve is smaller than the unloading area of ​​the second manual butterfly valve.

[0018] Optionally, a sub-screw machine is arranged below the front end of the main screw machine for precise metering of materials, and the second discharge port of the main screw machine is connected to the feed port of the sub-screw machine, and the discharge port of the sub-screw machine is connected to the feed port of the powder metering hopper of the mixing station.

[0019] Optionally, a discharge box is provided at the second discharge port of the main screw machine, and a feed box is provided at the feed port of the sub-screw machine. The discharge box is connected to the feed box, and part of the material in the main screw machine can enter the sub-screw machine through the discharge box. The discharge port of the sub-screw machine is connected to the discharge barrel.

[0020] The spiral lap device provided by the utility model includes a main screw machine and a lap screw machine, which are used to convey materials in a powder bin. The feed port of the main screw machine receives the materials and outputs the materials from the first discharge port of the main screw machine. The main screw machine is connected to the lap screw machine. The feed port of the lap screw machine receives the materials and conveys the materials to the main screw machine. The spiral conveying amount of the lap screw machine is less than or equal to the spiral conveying amount of the main screw machine. By configuring the main screw machine and the lap screw machine, the conveying amount of the lap screw machine is less than or equal to the conveying amount of the main screw machine, so as to achieve the function of balancing the conveying force, reducing pipe blockage, and improving productivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 It is a structural schematic diagram of the spiral lap joint device provided by the utility model;

[0023] Figure 2 It is a structural schematic diagram of a mixing station provided by the utility model.

[0024] Reference numerals:

[0025] 1: Overlap screw machine; 101: first reducer; 102: first feed hopper 103: Overlap discharge barrel;

[0026] 2: Main screw conveyor; 201: Second reducer; 202: Second feed hopper; 203: Overlap feed barrel;

[0027] 3: First rear powder bin; 301: First discharge barrel; 302: First butterfly valve;

[0028] 4: first front powder bin; 401: second discharge barrel; 402: second butterfly valve;

[0029] 5: Powder measuring hopper;

[0030] 6: Sub-screw machine. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described clearly and completely in conjunction with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0032] Combine the following Figure 1-Figure 2 The invention describes a spiral overlapping device and a mixing station.

[0033] like Figure 1 As shown, the spiral overlapping device provided by the utility model is used for overlapping more than two rows of powder bins in a mixing station, and includes an overlapping screw machine 1 and a main screw machine 2. The feed port of the overlapping screw machine 1 is used to connect the discharge port of the rear row of powder bin, the first feed port of the main screw machine 2 is used to connect the discharge port of the front row of powder bin, the discharge port of the overlapping screw machine 1 is connected to the second feed port of the main screw machine 2, the second feed port of the main screw machine 2 is used to connect the discharge port of the front row of powder bin, and the first discharge port of the main screw machine 2 is used to connect to the powder metering hopper of the mixing station.

[0034] A first motor is provided near the feed port of the overlapping screw machine 1, and the first motor is connected to the overlapping screw machine 1 through a first reducer 101. A second motor is provided near the second feed port of the main screw machine 2, and the second motor is connected to the main screw machine 2 through a second reducer 201. The screw conveying capacity of the overlapping screw machine 1 is less than or equal to the screw conveying capacity of the main screw machine 2.

[0035] The material in the rear powder bin is transported to the main screw machine 2 through the overlapping screw machine 1, and the main screw machine 2 transports the material transported by the overlapping screw machine 1 and the material in the front powder bin to the powder metering hopper of the mixing station.

[0036] Preferably, the speed ratio of the first reducer 101 is less than or equal to the speed ratio of the second reducer 201 , and the diameter of the spiral outer tube of the overlapping screw machine 1 is smaller than the diameter of the spiral outer tube of the main screw machine 2 .

[0037] Specifically, the overlapping screw machine 1 is a 219 screw machine, the speed ratio of the first reducer 101 is 1:7 or 1:10, the main screw machine 2 is a 273 screw machine, and the speed ratio of the second reducer 201 is 1:7.

[0038] Preferably, the diameter of the spiral outer tube of the overlapping screw machine 1 is the same as the diameter of the spiral outer tube of the main screw machine 2 , and the speed ratio of the first reducer 101 is smaller than the speed ratio of the second reducer 201 .

[0039] Specifically, the main screw machine 2 and the overlapping screw machine 1 are both 273 screw machines, the speed ratio of the second reducer 201 is 1:7, and the speed ratio of the first reducer 101 is 1:10.

[0040] The utility model provides a mixing station, including: Figure 1 The spiral lap joint device, powder bin and mixer shown in the figure, the powder bin includes more than two rows of powder bins, and two adjacent rows of powder bins are connected by Figure 1 The spiral overlapping device is used for overlapping, and the spiral overlapping device transports the material in the powder bin to the mixer.

[0041] like Figure 2 As shown, specifically, the powder bin is a double-row powder bin, which includes a first rear-row powder bin 3 and a first front-row powder bin 4. A first discharge barrel 301 is provided at the discharge port of the first rear-row powder bin 3, and a first manual butterfly valve 302 is installed on the first discharge barrel 301. The first front-row powder bin 4 is provided with a second discharge barrel 401, and a second manual butterfly valve 402 is installed on the second discharge barrel 401.

[0042] like Figure 1 As shown, a first feed hopper 102 is provided at the feed port of the overlapping screw machine 1, a second feed hopper 202 is provided at the first feed port of the main screw machine 2, an overlapping discharge barrel 103 is provided at the discharge port of the overlapping screw machine 1, and an overlapping feed barrel 203 is provided at the second feed port of the main screw machine 2. The overlapping discharge barrel 103 is connected to the overlapping feed barrel 203, and the material can be transported from the overlapping discharge barrel 103 to the overlapping feed barrel 203.

[0043] The mixer is provided with a powder measuring hopper 5 for rough and fine weighing of materials. A discharge barrel 204 is provided at the first discharge port of the main screw machine 2, and the discharge barrel 204 is connected to the feed port of the powder measuring hopper 5, and the materials can enter the powder measuring hopper 5 through the discharge barrel 204.

[0044] Preferably, the diameter of the spiral outer tube of the overlapping screw machine 1 is the same as the diameter of the spiral outer tube of the main screw machine 2, the speed ratio of the first reducer 101 is smaller than the speed ratio of the second reducer 201, and the unloading area of ​​the first manual butterfly valve 302 is smaller than the unloading area of ​​the second manual butterfly valve 402.

[0045] Preferably, a sub-screw machine 6 is provided below the front end of the main screw machine 2 for precise metering of materials. The second discharge port of the main screw machine 2 is connected to the feed port of the sub-screw machine 6 , and the discharge port of the sub-screw machine 6 is connected to the feed port of the powder metering hopper 5 .

[0046] Specifically, a discharge box is provided at the second discharge port of the main screw machine 2, and a feed box is provided at the feed port on the sub-screw machine 6. The discharge box is connected to the feed box. Part of the material in the main screw machine 2 can enter the sub-screw machine 6 through the discharge box. The discharge port of the sub-screw machine 6 is connected to the discharge barrel 204.

[0047] When the measured value of the powder measuring hopper 5 reaches the rough weighing value of the material, the main screw machine 2 is turned off, and then the sub-screw machine 6 is started to transport the material to the powder measuring hopper 5. When the measured value of the powder measuring hopper 5 reaches the precise weighing value of the material, the sub-screw machine 6 is turned off.

[0048] Conventional engineering mixing plants, especially high-speed rail engineering mixing plants, require long mixing time and other factors. Taking cement transportation as an example, the selection of main screw machine 2 is as follows:

[0049] For a mixing station with a productivity of 120 cubic meters per hour, a main screw conveyor with a specification of 273 is often used to transport cement; for a mixing station with a productivity of 180 cubic meters per hour, a main screw conveyor with a specification of 273 is often used to transport cement; for a mixing station with a productivity of 240 cubic meters per hour, a main screw conveyor with a specification of 325 is often used to transport cement.

[0050] There are many specifications of screw conveyors, and the size is usually indicated by the diameter of the spiral outer tube. Common specifications of screw conveyors in mixing stations are 219, 273, 325, etc. 219 screw means a screw conveyor with a spiral outer tube diameter of 219mm, and 273 screw means a screw conveyor with a spiral outer tube diameter of 273mm. The models of mixing stations are indicated and distinguished by the hourly productivity of the mixing station. 120, 180, and 240 respectively indicate that the productivity of the mixing station is 120 cubic meters per hour, 180 cubic meters per hour, and 240 cubic meters per hour.

[0051] The following takes the mixing station type 180, conveying cement as an example, and configures the main screw machine 2 and the overlapping screw machine 1 through verification calculation to achieve balanced production and avoid pipe blocking accidents. The angles of the main screw machine 2 and the overlapping screw machine 1 are set according to the distance from the 180 station powder bin to the mixer. The spiral inclination of the main screw machine 2 is 30 degrees, the distance from the overlapping feed barrel 203 to the discharge barrel 204 is 12 meters, and the distance from the first feed hopper 102 of the overlapping screw machine 1 to the overlapping discharge barrel 103 is less than 3 meters, and the spiral inclination is 11 degrees.

[0052] Example 1: In order to make the conveying capacity of the overlapping screw machine 1 less than or equal to the conveying capacity of the main screw machine 2, the preferred diameter downgrading is used, that is, the 273 screw machine is used as the main screw machine 2, and the 219 screw machine is used as the overlapping screw machine 1, and the conveying capacity of the main screw machine 2 and the speed ratio range of the first reducer 101 are calculated.

[0053] Screw conveyor conveying capacity calculation formula and parameter selection:

[0054] 1. Transport capacity Q = 47β*φ*ρ*D2*S*n, unit is t / h, i.e. tons / hour

[0055] In the formula, β represents the inclination coefficient, φ represents the material filling coefficient, and ρ represents the material density, the unit is t / m 3 , D2 represents the diameter of the spiral blade, the unit is m, S represents the pitch, the unit is m, and n represents the rotation speed, the unit is r / min.

[0056] The relationship between the tilt angle and the tilt coefficient:

[0057] Tilt angle: 0 degrees <5 degrees <10 degrees <15 degrees <20 degrees <30 degrees

[0058] Inclination coefficient β: 1.0 0.9 0.8 0.7 0.65 0.5

[0059] For powdery and granular materials with good fluidity and slight abrasiveness, such as grain, the material filling coefficient is φ=0.45; for materials with average fluidity and medium abrasiveness, such as coal, ash or cement, the material filling coefficient is φ=0.33; for materials with extremely high abrasiveness, such as furnace pond or river sand, the material filling coefficient is φ=0.15.

[0060] 2. Spiral diameter

[0061] The minimum spiral diameter is determined by the rotation speed and conveying volume, and the following conditions must be met: for conveying bulk materials, the spiral blade diameter D2 should be at least 10 times the maximum side length of the particles. If the material content of large particles is small, a smaller spiral blade diameter can also be selected, but it should be at least 4 times the maximum side length of the particles.

[0062] 3. Speed

[0063] The speed of the screw conveyor is not allowed to be too high, otherwise the conveyed material will be subjected to strong centrifugal effect, which will affect the conveying process. According to the JB / T7679-95 "Screw Conveyor" standard, each specification has 4 speeds to choose from.

[0064] 4. Speed ​​ratio of reducer

[0065] The speed ratios of conventional spiral reducers are 1:5, 1:7, and 1:10. The 273 main spiral machine is generally equipped with a reducer with a speed ratio of 1:7.

[0066] (1) Calculation of the conveying capacity of the main screw conveyor 2

[0067] Inclination coefficient β: Based on the spiral inclination of 30 degrees, the β value is 0.5;

[0068] Material filling coefficient φ: Taking cement as an example, the φ value is 0.33;

[0069] Cement density ρ: usually 1.25-1.6t / m 3 , generally takes a value of 1.3;

[0070] Spiral blade diameter D2 (273 spiral machine): 0.25m;

[0071] Pitch S: 0.25m;

[0072] Speed ​​n: The speed ratio of the second reducer 201 is 1:7, so the speed of the spiral body is 1460 / 7r / min. (The commonly used motor is 4-pole, and the speed is 1460r / min)

[0073] Main screw conveyor 2 conveying capacity Q = 47β*φ*ρ*D2*S*n

[0074] =47*0.5*0.33*1.3*0.25*0.25*1460 / 7

[0075] =131.4(t / h)

[0076] Then, the feeding amount per minute is 131.4 / 60=2.19t / min, so the feeding amount per second is 2190kg / 60=36.5kg / s. Taking C40 concrete as an example, the cement addition amount is 461kg / cubic meter, and the cement added by a 3-cubic meter machine is: 461x3=1.383t. Then, the required feeding time is:

[0077] 1383kg / 36.5kg / s=37.8 seconds, that is, cement can be mixed within 37.8 seconds, meeting the productivity of similar high-speed railway projects.

[0078] (2) Based on the fact that the delivery volume of the overlapping screw machine 1 is less than or equal to the delivery volume of the main screw machine 2, the speed ratio range of the first reducer 101 is calculated:

[0079] Inclination coefficient β: Based on the lap helix inclination of 11 degrees, the β value is 0.7;

[0080] Material filling coefficient φ: Taking cement as an example, the φ value is 0.33;

[0081] Cement density ρ: usually 1.25-1.6t / m 3 , generally takes the value of 1.3;

[0082] Spiral blade diameter D2 (219 spiral machine): 0.2m;

[0083] Pitch S: 0.2m;

[0084] Overlap screw conveyor 1 conveying capacity Q = 47β*φ*ρ*D2*S*n (t / h) ≤ 131.4t / h

[0085] =47*0.7*0.33*1.3*0.2*0.2*n(t / h)≤131.4t / h

[0086] n≤232.7

[0087] It is known that the speed of the reducer with a speed ratio of 1:5 is 1460 / 5=292r / min, the speed of the reducer with a speed ratio of 1:7 is 1460 / 7=208r / min, and the speed of the reducer with a speed ratio of 1:10 is 1460 / 10=146r / min, so the speed ratio of the first reducer 101 can be selected as 1:7 and 1:10.

[0088] Through the above theoretical calculations, we know that when a 219 screw machine is used as the overlapping screw machine 1, the speed ratio of the first reducer 101 is selected as 1:7 or 1:10, and the conveying capacity of the overlapping screw machine 1 is less than the conveying capacity of the main screw machine 2, this speed ratio configuration and screw diameter combination can fully meet the production needs without causing pipe blockage due to the mismatch of the productivity of the front and rear screw machines.

[0089] Example 2: Using a 273 screw machine as the main screw machine 2 and a 273 screw machine as the lap screw machine 1, the conveying capacity of the main screw machine 2 and the speed ratio range of the first reducer 101 are calculated.

[0090] (1) Calculation of the conveying capacity of the main screw conveyor 2

[0091] Inclination coefficient β: Based on the spiral inclination angle of 30 degrees, the β value is 0.5;

[0092] Material filling coefficient φ: Taking cement as an example, the φ value is 0.33;

[0093] Cement density ρ: usually 1.25-1.6t / m 3 , generally takes a value of 1.3;

[0094] Spiral blade diameter D2 (273 spiral machine): 0.25m;

[0095] Pitch S: 0.25m;

[0096] Speed ​​n: The speed ratio of the second reducer is 1:7, so the speed of the spiral body is 208.6r / min. (The commonly used motor is 4-pole, and the speed is 1460r / min)

[0097] Main screw conveyor 2 conveying capacity Q = 47β*φ*ρ*D2*S*n

[0098] =47*0.5*0.33*1.3*0.25*0.25*1460 / 7

[0099] =131.4(t / h)

[0100] (2) Based on the fact that the delivery volume of the overlapping screw machine 1 is less than or equal to the delivery volume of the main screw machine 2, the speed ratio range of the first reducer 101 is calculated.

[0101] Inclination coefficient β: Based on the lap helix inclination of 11 degrees, the β value is 0.7;

[0102] Material filling coefficient φ: Taking cement as an example, the φ value is 0.33;

[0103] Cement density ρ: usually 1.25-1.6t / m 3 , generally takes a value of 1.3;

[0104] Spiral blade diameter D2 (273 spiral machine): 0.25m;

[0105] Pitch S: 0.25m;

[0106] The conveying capacity of the overlapping screw machine 1 is Q = 47β*φ*ρ*D2*S*n (t / h) ≤ 131.4t / h

[0107] =47*0.7*0.33*1.3*0.25*0.25*n(t / h)≤131.4t / h

[0108] n≤149

[0109] It is known that the speed of the reducer with a speed ratio of 1:5 is 1460 / 5=292r / min, the speed of the reducer with a speed ratio of 1:7 is 1460 / 7=208r / min, and the speed of the reducer with a speed ratio of 1:10 is 1460 / 10=146r / min, so the speed ratio of the first reducer 101 can be selected as 1:10.

[0110] Through the above theoretical calculations, we know that the overlapping screw machine 1 adopts a 273 screw machine, the speed ratio of the first reducer 101 is 1:10, and the conveying capacity of the overlapping screw machine 1 is less than the conveying capacity of the main screw machine 2. This speed ratio configuration and screw diameter combination can fully meet the production needs without causing pipe blockage due to the mismatch of the productivity of the front and rear screw machines.

[0111] In summary, in order to achieve balanced production, the conveying capacity of the overlapping screw machine 1 must be less than or equal to the conveying capacity of the main screw machine 2. From the main screw machine 2 to the overlapping screw machine 1, a combination of diameter downgrading and speed ratio downgrading is generally adopted. The core point is to ensure that the actual conveying capacity of the overlapping screw machine 1 is less than or equal to the conveying capacity of the main screw machine 2.

[0112] In addition, in actual production, due to the use of overlapping screw machine 1 with the same diameter and smaller speed ratio, the conveying capacity of overlapping screw machine 1 is relatively close to that of main screw machine 2. In actual use, in order to obtain high reliability and prevent pipe blocking accidents, the discharge area of ​​the manual butterfly valve of the rear powder bin can be made smaller than the discharge area of ​​the front powder bin, that is, the discharge area of ​​the first manual butterfly valve 302 is smaller than the discharge area of ​​the second manual butterfly valve 402, so that the conveying capacity of overlapping screw machine 1 is less than or equal to the conveying capacity of main screw machine 2, and the productivity requirements are met.

[0113] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spiral lap joint device, used for lap joint of more than two rows of powder silos in a mixing station, characterized in that: It comprises an overlapping screw machine (1) and a main screw machine (2), wherein the feed port of the overlapping screw machine (1) is used to connect to the discharge port of the rear powder bin, the first feed port of the main screw machine (2) is used to connect to the discharge port of the front powder bin, the discharge port of the overlapping screw machine (1) is connected to the second feed port of the main screw machine (2), and the first discharge port of the main screw machine (2) is used to connect to the powder metering hopper of the mixing station; A first motor is provided near the feed inlet of the overlapping screw machine (1), and the first motor is connected to the overlapping screw machine (1) via a first reducer (101); a second motor is provided near the second feed inlet of the main screw machine (2), and the second motor is connected to the main screw machine (2) via a second reducer (201); The screw conveying capacity of the overlapping screw machine (1) is less than or equal to the screw conveying capacity of the main screw machine (2).

2. The spiral lap joint device according to claim 1, characterized in that: The speed ratio of the first reducer (101) is less than or equal to the speed ratio of the second reducer (201), and the diameter of the spiral outer tube of the overlapping screw machine (1) is smaller than the diameter of the spiral outer tube of the main screw machine (2).

3. The spiral lap joint device according to claim 2, characterized in that: The overlapping screw machine (1) is a 219 screw machine, the speed ratio of the first reducer (101) is 1:7 or 1:10, the main screw machine (2) is a 273 screw machine, and the speed ratio of the second reducer (201) is 1:

7.

4. The spiral lap joint device according to claim 1, characterized in that: The speed ratio of the first reducer (101) is smaller than the speed ratio of the second reducer (201), and the diameter of the spiral outer tube of the overlapping screw machine (1) is the same as the diameter of the spiral outer tube of the main screw machine (2).

5. The spiral lap joint device according to claim 4, characterized in that: The main screw machine (2) and the overlapping screw machine (1) are both 273 screw machines, the speed ratio of the second reducer (201) is 1:7, and the speed ratio of the first reducer (101) is 1:

10.

6. A mixing station, characterized in that: It comprises a spiral overlapping device, a powder silo and a mixer as described in any one of claims 1 to 5, wherein the powder silo comprises more than two rows of powder silos, two adjacent rows of powder silos are overlapped by the spiral overlapping device, and the spiral overlapping device transfers the material in the powder silo to the powder metering hopper of the mixing station.

7. The mixing station according to claim 6, characterized in that: The powder bin is a double-row powder bin, comprising a first rear-row powder bin (3) and a first front-row powder bin (4); a first discharge barrel (301) is provided at the discharge port of the first rear-row powder bin (3), and a first manual butterfly valve (302) is installed on the first discharge barrel (301); a second discharge barrel (401) is provided at the discharge port of the first front-row powder bin (4), and a second manual butterfly valve (402) is installed on the second discharge barrel (401); A first feed hopper (102) is provided at the feed inlet of the overlapping screw machine (1), a second feed hopper (202) is provided at the first feed inlet of the main screw machine (2), the first discharge barrel (301) is connected to the first feed hopper (102), and the second discharge barrel (401) is connected to the second feed hopper (202); The overlapping screw machine (1) is provided with an overlapping discharge barrel (103) at the discharge port, and the main screw machine (2) is provided with an overlapping feed barrel (203) at the second feed port, and the material can be transported from the overlapping discharge barrel (103) to the overlapping feed barrel (203); The mixer is provided with a powder measuring hopper (5) for roughly weighing and precisely measuring the material. A discharge barrel (204) is provided at the first discharge port of the main screw machine (2). The discharge barrel (204) is connected to the feed port of the powder measuring hopper (5). The material can enter the powder measuring hopper (5) through the discharge barrel (204).

8. The mixing station according to claim 7, characterized in that: The diameter of the spiral outer tube of the overlapping screw machine (1) is the same as the diameter of the spiral outer tube of the main screw machine (2), the speed ratio of the first reducer (101) is smaller than the speed ratio of the second reducer (201), and the discharge area of ​​the first manual butterfly valve (302) is smaller than the discharge area of ​​the second manual butterfly valve (402).

9. The mixing station according to claim 7, characterized in that: A sub-screw machine (6) is arranged below the front end of the main screw machine (2) for precise metering of materials. The second discharge port of the main screw machine (2) is connected to the feed port of the sub-screw machine (6), and the discharge port of the sub-screw machine (6) is connected to the feed port of the mixer.

10. The mixing station according to claim 9, characterized in that: A discharge box is provided at the second discharge port of the main screw machine (2), and a feed box is provided at the feed port of the sub-screw machine (6). The discharge box is connected to the feed box, and part of the material in the main screw machine (2) can enter the sub-screw machine (6) through the discharge box. The discharge port of the sub-screw machine (6) is connected to the discharge barrel (204).

Images