A method for casting and wrapping a multi-channel copper coil with aluminum liquid and a special casting device thereof

Abstract

The invention discloses a method for casting and wrapping a multi-channel copper coil with aluminum liquid and a special casting device thereof; the method belongs to the technical field of copper tube evaporators; the method comprises the following steps: (1) placing a prefabricated copper coil into a casting mold, connecting one end joint of the copper coil outside the casting mold to a high-pressure water source, the water pressure in the output pipe of the high-pressure water source being not less than 1.3 MPa, and the method is reserved; (2) melting aluminum material into aluminum liquid, and the method is reserved; (3) starting the high-pressure water source and maintaining the output of the high-pressure water, when high-pressure water flows out from the other end of the copper coil, pouring the melted aluminum liquid into the casting mold, the high-pressure water in the copper coil is instantly vaporized and sprayed out, and when the water output from the copper coil changes from high-pressure steam to high-pressure liquid water, the casting is completed; the invention aims to provide a method for casting and wrapping a multi-channel copper coil with aluminum liquid and a special casting device thereof with scientific process, simple operation and high efficiency; the method is used for casting copper coils with aluminum liquid.

Description

Technical Field

[0001] The present invention relates to a casting process, and more specifically, to a method for casting and wrapping a multi-channel copper coil with molten aluminum. The present invention also relates to a special casting device based on the method. Background Art

[0002] The existing copper-aluminum composite processes mainly include brazing; patch and screw locking; copper plugging and copper embedding; forging process (cold forging); and Crimped Fin technology. There is no hot casting technology because when the aluminum liquid at 660℃-720℃ is used to cast the copper tube, when the inside and surface of the copper tube are ≥370℃, hydrogen disease will occur, causing the copper tube to rupture and the casting cannot be successful.

[0003] When copper is heated in a reducing atmosphere containing hydrogen or carbon monoxide (≥370°C), hydrogen H 2 Or carbon monoxide CO easily reacts with cuprous oxide (Cu 2 O) to produce high-pressure water vapor or carbon dioxide gas, which can cause copper to crack. This phenomenon is often called "hydrogen disease" of copper. Summary of the invention

[0004] The first object of the present invention is to provide a method for casting and wrapping multi-channel copper coils with aluminum liquid with scientific process, simple operation and high efficiency in view of the deficiencies of the above-mentioned prior art.

[0005] The latter object of the present invention is to provide a special casting device based on the above method.

[0006] The previous technical solution of the present invention is achieved as follows: a method for casting and wrapping a multi-channel copper coil with molten aluminum, the method comprising the following steps:

[0007] (1) Place the prefabricated copper coil into a casting mold, connect one end of the copper coil outside the casting mold to a high-pressure water source, and ensure that the water pressure in the output pipe of the high-pressure water source is not less than 1.3 MPa, and keep it ready for use;

[0008] (2) melting the aluminum material into aluminum liquid for later use;

[0009] (3) Start the high-pressure water source and maintain the output of high-pressure water. When high-pressure water flows out from the other end of the copper coil, pour the molten aluminum liquid into the casting mold. The high-pressure water in the copper coil is instantly vaporized and sprayed out. When the water output from the copper coil changes from high-pressure steam to high-pressure liquid water, the casting is completed.

[0010] In the above-mentioned method of casting and wrapping a multi-channel copper coil with aluminum liquid, in step (1), the prefabrication of the copper coil is specifically as follows: bending copper coils of various shapes according to the required diameter and number of round tubes or special-shaped tubes, with the gap between adjacent copper coils being no less than 5 mm, brazing stainless steel or copper joints at both ends of the copper coil, and then immersing the entire copper coil in a deoxidizing brightening liquid for 1-3 minutes, taking it out and washing it with water, and then heating, dehumidifying and air-drying it to obtain the copper coil.

[0011] In the above-mentioned method for casting and wrapping a multi-channel copper coil with aluminum liquid, in step (1), when the inner diameter of the copper coil is 1-3 mm, the water pressure in the high-pressure water source output pipe is 2-5 MPa, and the water flow rate in the copper coil is 200-850 ml / min. The smaller the water pressure, the larger the water flow rate; when the inner diameter of the copper coil is 3-6 mm, the water pressure in the high-pressure water source output pipe is 1.5-2 MPa, and the water flow rate in the copper coil is 850-3650 ml / min. The smaller the water pressure, the larger the water flow rate; when the inner diameter of the copper coil is 6-20 mm, the water pressure in the high-pressure water source output pipe is 1.3-1.5 MPa, and the water flow rate in the copper coil is 3650-8250 ml / min. The smaller the water pressure, the larger the water flow rate.

[0012] In the above-mentioned method of casting and wrapping a multi-channel copper coil with aluminum liquid, in step (2), the aluminum material is smelted into aluminum liquid by: heating the furnace, adding the aluminum material into the furnace, and continuously heating the furnace to melt the aluminum material into aluminum liquid; when the furnace temperature rises to 660-680°C, pouring aluminum liquid deslagging and degassing powder into the furnace and stirring evenly, continuing to heat, and when the temperature rises to 690-720°C, removing the aluminum slag to obtain aluminum liquid.

[0013] In the above-mentioned method of casting and wrapping a multi-channel copper coil with molten aluminum, in step (3), the time for pouring the smelted aluminum liquid into the casting mold is 6-10 seconds.

[0014] In the above-mentioned method of casting and wrapping a multi-channel copper coil with molten aluminum, in step (2), the amount of slag and degassing powder for molten aluminum is 0.1-0.4% of the volume of the molten aluminum.

[0015] The latter technical solution of the present invention is achieved as follows: a special casting device based on the above-mentioned method of casting and wrapping a multi-channel copper coil with aluminum liquid, including a casting mold, the casting mold is provided with through holes matching the connecting heads at both ends of the copper coil, the outer diameter of the connecting heads at both ends of the copper coil is adapted to the inner diameter of the through holes, and the connecting heads located on the outside of the through holes are threadedly connected with fastening nuts, and the connecting heads are fixed in the corresponding through holes by the fastening nuts; the connecting heads at both ends of the copper coil are respectively connected to an adjustable pressure circulating cooling system through quick connectors.

[0016] In the above-mentioned special casting device, the casting mold includes a base plate fixed on an external support, a limiting boss adapted to the outer contour of the product to be formed is arranged on the base plate, and a plurality of side panels arranged vertically and detachably connected are attached to the outer wall of the limiting boss, and the through hole is formed on one of the side panels.

[0017] In the above-mentioned special casting device, the adjustable pressure circulating cooling system includes a condensation recovery tower, and the water storage chamber at the bottom of the condensation recovery tower is connected to an adjustable high-pressure water pump through a connecting pipe; the air inlet end of the condensation recovery tower is connected to the quick connector at one end of the copper coil through an air outlet pipe, and the water outlet end of the adjustable high-pressure water pump is connected to the quick connector at the other end of the copper coil through an inlet pipe.

[0018] In the above-mentioned special casting device, a water thermometer is arranged on the connecting pipe, a steam thermometer is arranged on the air outlet pipe, and a glass rotor flow regulator and a pressure gauge are arranged in sequence on the water inlet pipe along the water flow direction.

[0019] After adopting the above-mentioned process and special device, the present invention uses water cooling to solve the problem of "hydrogen disease" causing rupture when aluminum liquid is cast into copper tubes. The finished product is widely used in the most efficient and rapid heat absorption, heat release and heat exchange equipment required by industry, electronics industry and civil use, metallurgy and metal technology because of its fast cooling cycle, simplicity, low cost, environmental protection and energy saving, and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described in detail below in conjunction with the embodiments in the accompanying drawings, but this does not constitute any limitation to the present invention.

[0021] Figure 1 It is a structural schematic diagram of the device of the present invention;

[0022] Figure 2 1 is a schematic diagram of the side structure of the casting mold;

[0023] Figure 3 It is a schematic diagram of the top view structure of the casting mold.

[0024] In the figure: 1. casting mold; 1a. bottom plate; 1b. limiting boss; 1c. side plate; 2. through hole; 3. fastening nut; 4. quick connector; 5. adjustable pressure circulation cooling system; 5a. condensation recovery tower; 5b. connecting pipe; 5c. adjustable high-pressure water pump; 5d. outlet pipe; 5e. water inlet pipe; 6. water thermometer; 7. steam thermometer; 8. glass rotor flow regulator; 9. pressure gauge. DETAILED DESCRIPTION

[0025] A method for casting and wrapping a multi-channel copper coil with molten aluminum of the present invention comprises the following steps:

[0026] (1) Copper coils of various shapes are bent according to the required diameter and number of round or special-shaped tubes. The gap between adjacent copper coils is not less than 5mm, and stainless steel or copper joints are brazed at both ends of the copper coils. The brazed joint diameter requires that the outlet diameter must be greater than or equal to the inlet diameter, otherwise the internal pressure will be too high, resulting in instantaneous water shortage and temperature rise, hydrogen disease, and copper tube rupture.

[0027] After brazing, the whole tube is immersed in deoxidation brightening liquid for 1-3 minutes to remove the residual oxides from the surface welding, so that the thermal conductivity (401W / MK) of the welding port and the surface of the copper tube reaches the best. After immersion, take it out and wash it with water, then heat and dehumidify it and air dry it to avoid the phenomenon of gap between the copper tube surface and the aluminum liquid caused by the steam generated during casting, and then get the copper coil.

[0028] Place the prefabricated copper coil into the casting mold, and connect one end of the copper coil outside the casting mold to the high-pressure water source. When the inner diameter of the copper coil is 1-3mm, the water pressure in the high-pressure water source output pipe is 2-5MPa, and the water flow rate in the copper coil is 200-850ml / min. The lower the water pressure, the greater the water flow rate. When the water pressure takes the lower limit, the water flow rate takes the upper limit; when the inner diameter of the copper coil is 3-6mm, the water pressure in the high-pressure water source output pipe is 1. 5-2MPa, the water flow rate in the copper coil is 850-3650ml / min, the smaller the water pressure, the larger the water flow rate. When the water pressure takes the lower limit, the water flow rate takes the upper limit. When the inner diameter of the copper coil is 6-20mm, the water pressure in the high-pressure water source output pipe is 1.3-1.5MPa, and the water flow rate in the copper coil is 3650-8250ml / min. The smaller the water pressure, the larger the water flow rate. When the water pressure takes the lower limit, the water flow rate takes the upper limit. Standby.

[0029] (2) Heat the furnace, add aluminum material into the furnace, continue to heat it up to melt the aluminum material into aluminum liquid, when the furnace temperature rises to 660-680℃, pour aluminum liquid deslagging and degassing powder into the furnace and stir evenly, continue to heat up, when the temperature rises to 690-720℃, remove the aluminum slag to obtain aluminum liquid. The amount of aluminum liquid deslagging and degassing powder is 0.1-0.4% of the aluminum liquid volume. Aluminum liquid deslagging and degassing powder is an existing technology, and the existing conventional aluminum liquid deslagging and degassing powder can be used, which will not be repeated here. The function of aluminum liquid deslagging and degassing powder is to separate the residue and part of the hydrogen H in the aluminum liquid. 2 , improve the purity of aluminum liquid, make the surface of cast aluminum product smooth, without pores, white spots and scales, and achieve the best specific heat capacity coefficient (0.88*103J / KG℃).

[0030] (3) Start the high-pressure water source and maintain the output of high-pressure water. When high-pressure water flows out from the other end of the copper coil, pour the molten aluminum liquid into the casting mold. The pouring time is 6-10 seconds. The high-pressure water in the copper coil is instantly vaporized and sprayed out. When the water output from the copper coil changes from high-pressure steam to high-pressure liquid water, the casting is completed.

[0031] See also Figures 1 to 3 As shown, a special casting device based on the above-mentioned aluminum liquid casting and wrapping multi-channel copper coil method of the present invention includes a casting mold 1, and the casting mold 1 is provided with through holes 2 that match the connecting heads at both ends of the copper coil. The outer diameters of the connecting heads at both ends of the copper coil are adapted to the inner diameters of the through holes 2. The connecting heads located on the outsides of the through holes 2 are threadedly connected with fastening nuts 3, and the connecting heads are fixed in the corresponding through holes 2 by the fastening nuts 3; the connecting heads at both ends of the copper coil are respectively connected to an adjustable pressure circulating cooling system 5 through quick connectors 4.

[0032] Preferably, the casting mold 1 includes a base plate 1a fixed on an external support, and a limiting boss 1b adapted to the outer contour of the product to be formed is arranged on the base plate 1a, and a plurality of side panels 1c arranged vertically and detachably connected are attached to the outer wall of the limiting boss 1b, and the through hole 2 is formed on one of the side panels 1c.

[0033] Preferably, the adjustable pressure circulating cooling system 5 includes a condensation recovery tower 5a, and the water storage chamber at the bottom of the condensation recovery tower 5a is connected to an adjustable high-pressure water pump 5c through a connecting pipe 5b; the air inlet end of the condensation recovery tower 5a is connected to the quick connector 4 at one end of the copper coil through an air outlet pipe 5d, and the water outlet end of the adjustable high-pressure water pump 5c is connected to the quick connector 4 at the other end of the copper coil through a water inlet pipe 5e.

[0034] Furthermore, in order to observe key parameters such as water pressure, water temperature, steam temperature, etc. during casting in real time and intuitively, a water thermometer 6 is provided on the connecting pipe 5b, a steam thermometer 7 is provided on the air outlet pipe 5d, and a glass rotor flow regulator 8 and a pressure gauge 9 are provided in sequence on the water inlet pipe 5e along the water flow direction.

[0035] The device of the present invention can be cast automatically or manually. In the case of automatic casting, the relevant detection components and execution components, such as an adjustable high-pressure water pump, a water thermometer, a steam thermometer, a glass rotor flow regulator and a pressure gauge, need to be replaced with related models conventional in the art and can be connected to a control terminal (a conventional control terminal in the art such as a PLC or a single-chip microcomputer) to output or receive signals, which is also easy for those skilled in the art to think of.

[0036] During operation, the copper coil is brazed with a connector and connected to the casting mold. The connector is connected to the adjustable pressure circulation cooling system, and the system is started. After the water pressure in the copper coil is stable, the smelted aluminum liquid is injected into the casting mold within 6-10 seconds. When the high-pressure water flows through the inside of the high-temperature copper tube, it quickly cools down to below 370°C, so that it will not react with hydrogen disease, and instantly absorbs heat, cools down and protects the copper tube, so that the copper tube will not deform, crack or deteriorate. The copper tube is heated so that the water inside the flow tube is instantly vaporized and enters the condensation recovery tower. The steam is condensed and recycled. When the water volume in the water storage chamber at the bottom of the condensation recovery tower is insufficient, tap water is added through an external pipeline. The entire process achieves zero sewage discharge. When the water at the outlet changes from vapor to liquid, the cooling work inside the copper tube is completed. At this point, the aluminum liquid casting copper tube casting is successful. After experimental dissection of aluminum-copper castings, the surface of the copper tube inside the aluminum part is bright as new, the copper-aluminum joint is seamless and fully bonded, and the surface of the aluminum part is smooth and regular.

[0037] Screening experiments

[0038] Four types of spring-shaped copper coils were prepared, with inner diameters of 1.0 mm and outer diameters of 2.0 mm; inner diameters of 3 mm and outer diameters of 4 mm; inner diameters of 6 mm and outer diameters of 8 mm; and inner diameters of 20 mm and outer diameters of 22 mm. The length of each copper coil was 1 m. Screening experiments were conducted at different water pump pressures, different water flow rates in the pipes, and different pouring times of aluminum liquid. The specific experimental results are shown in Tables 1 to 4:

[0039] Table 1 Statistical data of the experimental results of copper tubes with an outer diameter of 2.0MM and an inner diameter of 1.0MM

[0040]

[0041]

[0042] From the data in the above table, it can be seen that casting can be successful when the pressure is not less than 3.2MPa and the water flow rate in the copper tube is not less than 200ml / min.

[0043] Table 2 Statistical data of the experimental results of copper tubes with an outer diameter of 4MM and an inner diameter of 3MM

[0044]

[0045]

[0046] From the data in the above table, it can be seen that casting can be successful when the pressure is not less than 2.0MPa and the water flow rate in the copper tube is not less than 850ml / min.

[0047] Table 3 Statistical data of the experimental results of copper tubes with an outer diameter of 8MM and an inner diameter of 6MM

[0048]

[0049]

[0050] From the data in the above table, it can be seen that casting can be successful when the pressure is not less than 1.5MPa and the water flow rate in the copper tube is not less than 3650ml / min.

[0051] Table 4 Statistical data of the experimental results of copper tubes with an outer diameter of 22MM and an inner diameter of 20MM

[0052]

[0053] From the data in the above table, it can be seen that casting can be successful when the pressure is not less than 1.3MPa and the water flow rate in the copper tube is not less than 8250ml / min.

[0054] In the above experiments, the flow rate values ​​at the beginning of the experiments were all carried out with the glass rotor flow regulator fully open, that is, without flow restriction, in order to find the optimal value.

[0055] Through the above experimental analysis, it is found that the smaller the inner diameter of the copper tube, the greater the required pressure value. At the beginning of the experiment, the researchers believed that the smaller the inner diameter of the copper tube, the smaller the required water pressure, as long as the water flow in the copper tube was full.

[0056] In addition, during the experiment, the researchers believed that as long as the water pressure was high enough, the temperature of the steam output from the copper tube would be low, and copper tubes of all diameters could be used. In other words, the higher the water pressure, the better, safer, and the higher the success rate. However, through the analysis of the experimental data, it was found that when the pressure reached a certain value, the pressure continued to increase, and the temperature of the steam output from the copper tube remained basically unchanged, which had no substantial impact on the final effect of the experiment, and only increased energy consumption. This was also beyond the expectations of the researchers.

[0057] The above embodiments are preferred implementation modes of the present invention and are only used to facilitate the description of the present invention. They are not intended to limit the present invention in any form. Any person with ordinary knowledge in the relevant technical field, if they do not depart from the scope of the technical features of the present invention, can make equivalent embodiments by partial changes or modifications to the technical contents disclosed in the present invention, and they still fall within the scope of the technical features of the present invention without departing from the technical features of the present invention.

Claims

1. A method for casting and wrapping a multi-channel copper coil with molten aluminum, characterized in that: The method comprises the following steps: (1) Place the prefabricated copper coil into the casting mold, and connect one end of the copper coil outside the casting mold to the high-pressure water source; wherein the inner diameter of the copper coil is 1 mm, the water pressure in the high-pressure water source output pipe is not less than 3.2 MPa, and the water flow rate in the copper tube is not less than 200 ml / min; or the inner diameter of the copper coil is 3 mm, the water pressure in the high-pressure water source output pipe is not less than 2 MPa, and the water flow rate in the copper tube is not less than 850 ml / min; or the inner diameter of the copper coil is 6 mm, the water pressure in the high-pressure water source output pipe is not less than 1.5 MPa, and the water flow rate in the copper tube is not less than 3650 ml / min; or the inner diameter of the copper coil is 20 mm, the water pressure in the high-pressure water source output pipe is not less than 1.3 MPa, and the water flow rate in the copper tube is not less than 8250 ml / min; (2) Melting the aluminum material into molten aluminum for later use; (3) Start the high-pressure water source and maintain the output of high-pressure water. When high-pressure water flows out from the other end of the copper coil, pour the molten aluminum into the casting mold. The high-pressure water in the copper coil is instantly vaporized and sprayed out. When the water output from the copper coil changes from high-pressure steam to high-pressure liquid water, the casting is completed.

2. The method for casting and wrapping a multi-channel copper coil with molten aluminum according to claim 1, characterized in that: In step (1), the prefabrication of the copper coil is specifically as follows: the copper coil is bent into various shapes according to the required diameter and number of round tubes or special-shaped tubes, the gap between adjacent copper coils is not less than 5 mm, stainless steel or copper joints are brazed at both ends of the copper coil, and the whole is immersed in a deoxidizing brightening liquid for 1-3 minutes, taken out and washed with water, and then heated, dehumidified and air-dried to obtain the copper coil.

3. The method for casting and wrapping a multi-channel copper coil with molten aluminum according to claim 1, characterized in that: In step (2), the aluminum material is smelted into aluminum liquid by heating a melting furnace, adding the aluminum material into the melting furnace, and continuously raising the temperature to melt the aluminum material into aluminum liquid. When the temperature of the melting furnace rises to 660-680°C, pouring aluminum liquid deslagging and degassing powder into the melting furnace and stirring evenly, and continuing to raise the temperature. When the temperature rises to 690-720°C, the aluminum slag is removed to obtain aluminum liquid.

4. The method for casting and wrapping a multi-channel copper coil with molten aluminum according to claim 1, characterized in that: In step (3), the time for pouring the smelted aluminum liquid into the casting mold is 6-10 seconds.

5. The method for casting and wrapping a multi-channel copper coil with molten aluminum according to claim 3, characterized in that: In step (2), the amount of aluminum liquid deslagging and degassing powder used is 0.1-0.4% of the aluminum liquid volume.

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