Pneumatic suspension device with nozzle convenient to replace

Abstract

The invention relates to the technical field of material smelting, in particular to a pneumatic suspension device with a nozzle convenient to replace. Comprising a sealed cavity, a supporting table arranged in the cavity, a suspension nozzle, a heating laser source and an observation window. A through gas channel is formed in the supporting table, and an inlet of the gas channel is communicated with a gas source outside the cavity; the lower end of the suspension nozzle is connected with the upper end of the supporting table through a detachable mechanical connecting structure, and an internal channel of the suspension nozzle is communicated with a gas channel of the supporting table; the incidence direction of a laser beam of the heating laser source faces an area above the suspension nozzle; and the observation window is arranged on the wall surface of the cavity. The suspension nozzle and the supporting table are arranged to be of a detachable connection structure, rapid replacement of the nozzle is achieved, a matched nozzle can be selected conveniently according to the type and size of sample materials, the maintenance cost is reduced, and the maintenance time is shortened; the vertical continuity and suspension stability of airflow are ensured by ensuring that the nozzle coincides with the central axis of the gas channel of the supporting table.

Description

Technical Field

[0001] This invention relates to the field of materials smelting technology, and more specifically to a pneumatic suspension device that facilitates nozzle replacement. Background Technology

[0002] Thermophysical properties of liquids are important parameters describing the behavior of materials during cooling from a melt. For metallic alloys, thermophysical properties play a crucial role in casting applications. Density, surface tension, and viscosity are not only key parameters for understanding the casting process of a particular material from a technical perspective, but also fundamental to numerical modeling. Today, industry requires numerical modeling of many processes, including welding and additive manufacturing; therefore, understanding the thermophysical properties of these materials is essential for improving numerical models.

[0003] Non-contact methods for suspending samples have shown good performance in characterizing liquid metals. Pneumatic levitation technology suspends samples using a gas jet from a conical nozzle, achieving a containerless state. This method is applicable to both metallic and non-metallic materials and can measure density and viscosity at temperatures above 2000 K. However, in existing pneumatic levitation devices, the levitation nozzle is usually fixed to a base. When the nozzle is damaged due to prolonged use or accidental contact with a high-temperature molten sample, the entire base structure needs to be replaced, resulting in high maintenance costs and long downtime. Furthermore, different sample materials require nozzles made of different materials to avoid reactions, and fixed nozzle structures cannot meet the need for rapid replacement. In addition, most existing devices use a single-beam laser to heat the sample from the top, resulting in a large temperature gradient inside the sample, affecting the accuracy of property measurements. The integration of the chamber atmosphere control system is low, making it difficult to accurately control the experimental environment. Sample handling and chamber cleaning are cumbersome, impacting experimental efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a pneumatic suspension device with easy nozzle replacement, so as to solve the technical problems in the prior art such as inconvenient replacement of suspension nozzles, high maintenance costs, uneven heating, and inaccurate atmosphere control.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A pneumatic levitation device with easily replaceable nozzles includes a sealed cavity providing a closed environment for sample levitation and heating, preventing sample oxidation or contamination; a support platform disposed inside the cavity, the support platform having a through gas channel whose inlet is connected to a gas source outside the cavity for introducing suspended gas into the cavity; a levitation nozzle, the lower end of which is connected to the upper end of the support platform via a detachable mechanical connection structure, the internal channel of the levitation nozzle communicating with the gas channel of the support platform, the upper opening of the levitation nozzle facing the interior of the cavity for levitizing the sample above the nozzle by ejected gas flow; at least one heating laser source, the laser beam of the heating laser source incident on the area above the levitation nozzle for heating and melting the suspended sample; and at least one observation window disposed on the wall of the cavity for optical monitoring of the sample state.

[0007] Furthermore, the detachable mechanical connection structure is a threaded connection structure, including an internal thread on the upper end of the support platform and an external thread on the lower end of the suspension nozzle, which enables quick assembly and disassembly of the nozzle through threaded engagement; the central axis of the gas channel of the support platform coincides with the central axis of the internal channel of the suspension nozzle to ensure that the airflow is vertically upward and to ensure stable suspension of the sample.

[0008] Furthermore, the material of the suspended nozzle is boron nitride, zirconium oxide ceramic, or copper-based material. The appropriate nozzle material is selected according to the characteristics of the sample material to avoid reaction when the sample comes into contact with the nozzle or damage to the nozzle due to high temperature.

[0009] Further specifying, the cavity wall is provided with multiple windows, including: a top window located at the top for transmitting a heating laser beam; at least one high-speed camera window located on the side for mounting a high-speed camera to record the sample vibration process; at least one backlight window located on the side for mounting a light source to provide backlight illumination required for sample imaging; and at least one temperature measuring window located at the top for mounting an infrared thermometer to monitor the sample temperature in real time.

[0010] Furthermore, the support platform is a hollow structure with a light-transmitting window at its bottom, which transmits another laser beam from below, enabling the sample to be heated symmetrically from top to bottom and reducing the temperature gradient inside the sample.

[0011] Further specifying, it also includes an acoustic excitation system comprising at least one loudspeaker mounted on a pipe communicating with the cavity, for generating sound waves to excite the sample to vibrate, transmitting the sound waves to the sample via a suspended gas, inducing surface oscillations in the sample, so as to measure the surface tension and viscosity of the sample by an oscillating drop method.

[0012] Furthermore, there are two loudspeakers, which are arranged opposite each other on the side wall of the pipe, and the line connecting the centers of the two loudspeakers is perpendicular to the gas flow direction, so as to ensure that the sound waves act uniformly on the sample and excite the required second-order surface oscillation.

[0013] Further specifying, it also includes an atmosphere conditioning system, which includes: a vacuum pump unit connected to the large outlet of the cavity for evacuating the cavity; a mechanical pump and a pressure relief valve connected to the small outlet of the cavity for precisely regulating the pressure inside the cavity; and an inert gas source connected to the upper inlet of the cavity for filling the cavity with inert gas to protect the sample.

[0014] Furthermore, the upper air inlet and the large air outlet are connected by a pipe to form a gas washing circuit, which is used to repeatedly fill and discharge inert gas into the cavity before the experiment, so as to effectively remove the active gas in the cavity and ensure that the sample is tested in a pure atmosphere.

[0015] Further, it also includes a gas flow controller, the inlet of which is connected to the gas source, and the outlet of which is connected to the lower air inlet of the gas channel of the support platform, for precisely controlling the flow rate of the suspended gas so that the sample can be stably suspended above the nozzle.

[0016] Furthermore, the cavity wall is provided with a quick-opening door, one side of which is connected to the cavity via a hinge, and the other side of which is provided with a locking handle. An auxiliary observation window is provided on the quick-opening door. The quick-opening door structure facilitates operators to quickly take or put in samples or clean the inside of the cavity, thereby improving experimental efficiency.

[0017] Furthermore, the bottom of the cavity is provided with multiple support feet to place the device stably on the operating table, ensuring the stability of the device during the experiment.

[0018] Furthermore, the support feet are four in number, evenly distributed at the four corners of the bottom of the cavity, providing stable support.

[0019] Furthermore, the heating laser source is multiple, and the incident direction of the laser beams of the multiple heating laser sources is respectively pointed to the area above the suspending nozzle. The sample is uniformly heated by multi-angle heating, the temperature gradient is reduced, and the requirements of high-precision physical property measurement are met.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) This invention achieves rapid nozzle replacement by setting the suspension nozzle and support platform as a detachable connection structure, especially by using a threaded connection. This facilitates the selection of a suitable nozzle according to the type and size of the sample material. At the same time, when the nozzle is damaged due to high-temperature contact, there is no need to replace the entire support structure, reducing maintenance costs and time. By ensuring that the central axis of the gas channel of the nozzle and the support platform is coincident, the vertical continuity of the airflow and the suspension stability are guaranteed, so that the sample can remain stably suspended during heating and cooling, thus improving the success rate of the experiment. (2) By setting up an acoustic excitation system, forced vibration of the droplets can be induced, thereby measuring the surface tension and viscosity of the sample by the oscillating drop method, realizing non-contact measurement of the physical properties of high-temperature melts. By setting up an atmosphere conditioning system and a gas washing circuit, the atmosphere environment inside the chamber can be precisely controlled to prevent sample oxidation and ensure the accuracy and reliability of experimental data. (3) By setting up a multi-channel laser heating system, symmetrical heating of the sample from top to bottom is achieved, effectively reducing the temperature gradient inside the sample and improving the accuracy of physical property measurement. By providing support feet at the bottom of the chamber, the device can be placed stably on various operating surfaces; by incorporating a quick-opening door structure, it is convenient for operators to quickly pick up or put down samples or clean the inside of the chamber, thus improving the convenience and efficiency of experimental operations. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the installation of this pneumatic suspension device.

[0023] Figure 2 This is a schematic diagram of the structure of this pneumatic suspension device.

[0024] Figure 3 This is a cross-sectional view of the cavity of this pneumatic levitation device.

[0025] Figure 4 This is a schematic diagram illustrating the working principle of this pneumatic suspension system.

[0026] In the diagram: 1. Cavity; 2. Support foot; 3. Quick-opening door; 4. Locking handle; 5. Auxiliary observation window; 6. Hinge; 7. Top window; 8. High-speed camera window; 9. Backlight window; 10. Upper air inlet; 11. Lower air inlet; 12. Small air outlet; 13. Large air outlet; 14. Suspended nozzle; 15. Sample; 16. Support platform; 17. Gas channel; 18. Transparent window; 19. Temperature measurement window; 20. Infrared thermometer; 21. Heating laser source; 22. Optical path; 23. Pressure relief valve; 24. Mechanical pump; 25. Vacuum pump unit; 26. High-speed camera; 27. Light source; 28. Pipeline; 29. ​​Inert gas source; 30. Gas flow controller; 31. Speaker. Detailed Implementation

[0027] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0028] like Figures 1 to 4 As shown in the figure, an embodiment of the present invention provides a pneumatic levitation device that facilitates nozzle replacement, including a sealed cavity 1, a support platform 16, a levitation nozzle 14, a heated laser source 21, and an observation window.

[0029] The chamber 1 is made of stainless steel and is cubic in shape. It provides a sealed environment for sample suspension and heating, preventing the sample from oxidizing at high temperatures or being contaminated by external factors. The bottom of the chamber 1 is provided with multiple support feet 2, preferably four, which are evenly distributed at the four corners of the bottom of the chamber 1. Their function is to place the device stably on the operating table, ensuring the stability of the device during the experiment and preventing the suspension state of the sample from being affected by vibration or tilting.

[0030] A support platform 16 is disposed inside the cavity 1. A vertically penetrating gas channel 17 is provided inside the support platform 16. The inlet of the gas channel 17 is connected to a gas source outside the cavity 1, used to introduce suspended gas into the cavity 1. Specifically, in this embodiment, the gas source is a high-purity argon gas cylinder with an argon purity ≥99.999% and an oxygen content less than 1.5 ppm to prevent sample oxidation at high temperatures. The function of the support platform 16 is to fix the suspension nozzle 14 and guide the gas vertically upward, ensuring accurate gas flow direction.

[0031] The lower end of the suspension nozzle 14 is connected to the upper end of the support platform 16 via a detachable mechanical connection structure. The internal channel of the suspension nozzle 14 communicates with the gas channel 17 of the support platform 16. The upper opening of the suspension nozzle 14 faces the interior of the cavity 1, allowing the sample 15 to be suspended above the nozzle by the ejected airflow. The suspension nozzle 14 adopts a converging conical structure. This geometry can generate a stable airflow field, enabling the sample 15 to be stably suspended above the nozzle, exposing 3 / 4 of the sample volume and meeting the requirements of the observation field. The detachable connection structure facilitates the quick replacement of suitable nozzles according to the type and size of the sample material. When the nozzle is damaged due to high-temperature contact, only the nozzle needs to be replaced without replacing the entire support platform, greatly reducing maintenance costs and time.

[0032] like Figure 3As shown, in this embodiment, the detachable mechanical connection structure is a threaded connection structure, including an internal thread on the upper end of the support platform 16 and an external thread on the lower end of the suspension nozzle 14. The nozzle can be quickly installed and removed through the threaded engagement. When the nozzle is installed in place, the central axis of the gas channel 17 of the support platform 16 coincides with the central axis of the internal channel of the suspension nozzle 14. The function of this coaxial design is to ensure that the airflow acts vertically upward on the bottom of the sample 15, avoiding the sample drifting or falling due to the skewed airflow, and ensuring that the sample can be stably suspended.

[0033] The material of the suspension nozzle 14 can be selected according to the characteristics of the sample material. Specifically, in this embodiment, the suspension nozzle 14 is made of copper-based material, taking advantage of its high thermal conductivity and easy processing properties. For different sample materials, nozzles made of boron nitride or zirconium oxide ceramic can be used to avoid reactions when the sample comes into contact with the nozzle.

[0034] At least one heating laser source 21 is used, with its laser beam incident in the area above the suspension nozzle 14, for heating and melting the suspended sample 15. In this embodiment, the heating laser source 21 consists of two continuous fiber lasers, which are incident vertically onto the sample surface through the top window 7 and the bottom transparent window 18. The effect of symmetrical heating from top to bottom is to effectively reduce the temperature gradient inside the sample, thereby reducing the measurement error of physical properties caused by temperature inhomogeneity and improving the measurement accuracy of density, surface tension, and viscosity.

[0035] The observation windows are located on the wall of cavity 1 for optical monitoring of the sample state. Specifically, in this embodiment, multiple windows are provided on the wall of cavity 1, including: a top window 7 for transmitting the heating laser beam; at least one high-speed camera window 8 on the side for mounting a high-speed camera 26 to record the sample vibration process; at least one backlight window 9 on the side for mounting a light source 27 to provide backlight illumination for sample imaging; and at least one temperature measuring window 19 on the top for mounting an infrared thermometer 20 to monitor the sample temperature in real time. These windows enable multi-angle observation of the sample. The high-speed camera window 8, in conjunction with the backlight window 9, can obtain a clear image of the sample outline for subsequent image analysis; the temperature measuring window 19 is used for non-contact temperature measurement, providing real-time feedback of the sample temperature to control the heating process.

[0036] The support stage 16 has a hollow structure with a light-transmitting window 18 at its bottom for transmitting another laser beam from below. The light-transmitting window 18 is made of sapphire material, allowing the bottom laser beam to pass through the gas channel 17 of the support stage 16 and act on the bottom of the sample 15, achieving symmetrical heating from top to bottom. The purpose of this structure is to avoid interference between the optical path 22 and the gas path, while ensuring that the bottom laser can successfully heat the sample.

[0037] like Figure 4As shown, the apparatus of this embodiment also includes an acoustic excitation system for measuring the surface tension and viscosity of a sample using the oscillating drop method. The acoustic excitation system includes at least one loudspeaker 31, which is mounted on a pipe 28 communicating with the cavity 1. The loudspeaker 31 generates sound waves to excite the sample to vibrate. These sound waves are transmitted to the sample via a suspended gas, inducing surface oscillations. The acoustic excitation system enables non-contact forced vibration of the droplet. By analyzing the vibration frequency and damping, the surface tension and viscosity can be calculated, which is impossible with traditional contact methods.

[0038] like Figure 4 As shown, the apparatus in this embodiment also includes an atmosphere conditioning system for precisely controlling the atmosphere within the chamber 1. The atmosphere conditioning system includes: a vacuum pump unit 25 connected to the large outlet 13 of the chamber 1 for evacuating the chamber 1; a mechanical pump 24 and a pressure relief valve 23 connected to the small outlet 12 of the chamber 1 for precisely regulating the pressure within the chamber 1 to maintain it within the range required for sample suspension; and an inert gas source 29 connected to the upper inlet 10 of the chamber 1 for filling the chamber 1 with inert gas to protect the sample. The function of the atmosphere conditioning system is to create and maintain the specific atmosphere required for the sample (such as inert gas protection) to prevent sample oxidation or volatilization at high temperatures, while adjusting the pressure optimizes suspension stability.

[0039] The upper air inlet 10 and the large air outlet 13 are connected by a pipe to form a gas washing circuit, which is used to repeatedly fill and discharge inert gas into the chamber 1 before the experiment to effectively remove reactive gases from the chamber 1. The gas washing operation is performed for 2 to 4 cycles to ensure that the sample is tested in a pure atmosphere. The function of the gas washing circuit is to thoroughly remove residual oxygen and other reactive gases from the chamber.

[0040] The device in this embodiment also includes a gas flow controller 30. The inlet of the gas flow controller 30 is connected to a gas source, and the outlet of the gas flow controller 30 is connected to the lower air inlet 11 of the gas channel 17 of the support platform 16. It is used to precisely control the flow rate of the suspended gas to adapt to samples of different sizes and densities and ensure suspension stability.

[0041] A quick-opening door 3 is provided on the wall of cavity 1. One side of the quick-opening door 3 is connected to cavity 1 via a hinge 6, and the other side of the quick-opening door 3 is provided with a locking handle 4. By rotating the handle, the quick-opening door 3 can be pressed tightly onto cavity 1 to achieve a seal. An auxiliary observation window 5 is provided on the quick-opening door 3, allowing the operator to observe the internal state without opening cavity 1. A sealing ring is provided between the quick-opening door 3 and cavity 1 to ensure vacuum sealing performance when closed. The quick-opening door structure allows the operator to quickly put in or take out samples or clean the inside of the cavity.

[0042] When using the apparatus of this embodiment to perform sample melting and property measurement experiments, the operation procedure is as follows:

[0043] First, select a suitable suspension nozzle 14 based on the sample material and install it on the support platform 16 via a threaded connection. Place a spherical sample 15 with a diameter of 1.5-2.5 mm above the nozzle.

[0044] Close the quick-opening door 3 and all valves, and start the vacuum pump unit 25 to evacuate chamber 1 to below 5e-4 Pa. After stopping the evacuation, fill chamber 1 with high-purity argon gas and perform gas cleaning cycles 2 to 4 times.

[0045] The suspension flow rate is adjusted to below 1 L / min by the gas flow controller 30, so that the sample 15 is stably suspended above the nozzle without falling.

[0046] Turn on the top heating laser source 21 to preheat the sample. After the sample 15 has completely melted, turn on the bottom heating laser source 21 to achieve symmetrical heating from top to bottom.

[0047] After the sample temperature stabilizes, the acoustic excitation system is activated, generating sinusoidal sound waves through a speaker for frequency scanning, thus exciting the sample to produce second-order surface oscillations. A high-speed camera 26 records the droplet vibration process at a high frame rate, and the image data is transmitted to a computer for post-processing to extract the oscillation period and deformation characteristics. An infrared thermometer 20 monitors the sample temperature in real time.

[0048] After the experiment, turn off the heating laser source 21 and allow the sample 15 to cool naturally to room temperature. Turn off the gas flow controller 30, open the quick-opening door 3, remove the sample 15, weigh it, and record the mass change before and after the experiment for subsequent data correction.

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A pneumatic suspension device with easily replaceable nozzles, characterized in that, include: A sealed cavity; a support platform disposed inside the cavity, the support platform having a through gas channel inside, the inlet of the gas channel being connected to a gas source outside the cavity; a suspended nozzle, the lower end of which is connected to the upper end of the support platform via a detachable mechanical connection structure, the internal channel of the suspended nozzle being connected to the gas channel of the support platform, and the upper opening of the suspended nozzle facing the interior of the cavity; At least one heating laser source, wherein the laser beam incident direction of the heating laser source is toward the region above the levitation nozzle; At least one observation window is provided on the wall of the cavity.

2. The pneumatic levitation device according to claim 1, characterized in that, The detachable mechanical connection structure is a threaded connection structure, including an internal thread provided on the upper end of the support platform and an external thread provided on the lower end of the suspension nozzle; the central axis of the gas channel of the support platform coincides with the central axis of the internal channel of the suspension nozzle.

3. The pneumatic levitation device according to claim 1, characterized in that, The suspended nozzle is made of boron nitride, zirconium oxide ceramic, or copper-based material.

4. The pneumatic levitation device according to claim 1, characterized in that, The cavity wall is provided with multiple windows, including: a top window at the top; at least one high-speed camera window on the side; at least one backlight window on the side; and at least one temperature measuring window at the top.

5. The pneumatic levitation device according to claim 4, characterized in that, The support platform has a hollow structure with a light-transmitting window at its bottom.

6. The pneumatic levitation device according to claim 1, characterized in that, It also includes an acoustic excitation system comprising at least one loudspeaker mounted on a pipe communicating with the cavity.

7. The pneumatic levitation device according to claim 6, characterized in that, The speaker consists of two speakers, which are positioned opposite each other on a pipe that communicates with the cavity, and the line connecting the centers of the two speakers is perpendicular to the direction of airflow in the pipe.

8. The pneumatic levitation device according to claim 1, characterized in that, It also includes an atmosphere conditioning system, which comprises: a vacuum pump unit connected to the large outlet of the cavity; a mechanical pump and a pressure relief valve connected to the small outlet of the cavity; and an inert gas source connected to the upper inlet of the cavity.

9. The pneumatic levitation device according to claim 8, characterized in that, The upper air inlet and the large air outlet are connected by a pipe to form a washing air circuit.

10. The pneumatic levitation device according to claim 1, characterized in that, It also includes a gas flow controller, the inlet of which is connected to the gas source, and the outlet of which is connected to the lower air inlet of the gas channel of the support platform.

11. The pneumatic levitation device according to claim 1, characterized in that, A quick-opening door is provided on the wall of the cavity. One side of the quick-opening door is connected to the cavity via a hinge, and the other side of the quick-opening door is provided with a locking handle. An auxiliary observation window is provided on the quick-opening door.

12. The pneumatic levitation device according to claim 1, characterized in that, The bottom of the cavity is provided with multiple support feet.

13. The pneumatic levitation device according to claim 12, characterized in that, The support has four feet.

14. The pneumatic levitation device according to claim 1, characterized in that, The heating laser source is multiple, and the incident direction of the laser beams of the multiple heating laser sources is respectively pointed to the area above the suspended nozzle.

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