Metal - Air dispersion system User Manual
Jesse Hameete
November 13, 2020
Contents
1 Introduction 4
1.1 Target audience . . . 4 1.2 Safety . . . 4
2 Overview of set up 5
3 Calibration 7
3.1 Calibration setup . . . 7 3.2 Calibration procedure . . . 8
4 Operation of the dispersion system 10
4.1 Filling the system . . . 10 4.2 Controlling the airflow . . . 11 4.3 Controlling the powder flow . . . 13
List of Figures
2.1 Schematic image of the final setup . . . 5
2.2 Picture of the setup of the dispersion system. The lid of the airtight box has been removed for a clear overview. . . 6
3.1 Schematic overview of the calibration setup. . . 7
4.1 Schematic figure displaying the exploded view of the system . . . 11
4.2 The hopper is being filled with powder using the provided cone. . . 12
4.3 Graphic User Interface of the LabVIEW program. . . 12
4.4 Thyristor regulator with a multimeter as it is used in the dispersion system. . 14
4.5 Calibration data for the 2 powders that were considered in this experiment, the Rio Tinto powder (a) and the TLS technik powder (b). . . 14
3
Chapter 1 Introduction
This document describes the working principle and operation instructions of the dispersion system that was created to provide an iron powder aerosol to the heat flux burner. In chapter two, the overview of the set up is given, along with images of the components. Chapter three describes how to calibrate new powders, and gives a calibration table for the most used powders that are already calibrated. Chapter four gives detailed step-by-step information of how to use the dispersion system.
1.1 Target audience
This device and these instructions are targeted at employees or students of the Eindhoven University of Technology that have been trained to use this device. Use of the device without a trained student or employee is not recommended.
1.2 Safety
Use of this device outside of the heat flux burner or use of this device outside the parameters that are stated in this document is at risk of the user and is generally not recommended, as it may cause harm to the individuals.
Always make sure there is a means to extract the aerosol, as breathing in metal powder is a health hazard.
Chapter 2
Overview of set up
The dispersion system can be seen schematically in figure 2.1 and consists of two main components; the vacuum ejector and the vibration feeder. Both these components are sealed in an airtight container. The container has two inlets for air supply. One of these inlets is connected directly to the inlet of the vacuum ejector, and the other one provides an air flow to the container that is then taken in by the vacuum side of the vacuum ejector along with the powder flow. Inside the vacuum ejector, the powder mixes with the primary air flow and an aerosol comes out of the venturi and is then led out of the airtight container to the heat flux burner.
Figure 2.1: Schematic image of the final setup
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Jesse Hameete CHAPTER 2. OVERVIEW OF SET UP
figure 2.2 shows the setup with the container unsealed. Here, the entrance of the cables that provide the airflow can be seen,
Figure 2.2: Picture of the setup of the dispersion system. The lid of the airtight box has been removed for a clear overview.
Chapter 3 Calibration
Calibration of powders is required in order to accurately predict the aerosol density of the dispersion system when it is used with different powders. Parameters such as particle size and sphericity of the powder may influence the feed rate of the vibration system and thus give a different feed rate for different types of powders. The calibration procedure that is described below has been executed for the three most used types of powders; Rio Tinto, TLS, and Sigma Aldrich (add powder diameter).
Beware: The vibration feed rate can be adjusted by adjusting the min and max value of the potentiometers within the thyristor regulator. When this is done, the calibrated values become invalid and calibration has to be started over.
3.1 Calibration setup
Figure 3.1 shows the setup as it should be used to calibrate the feed rate of the powders. A weighing system should be installed that can accurately and continuously output a weighed value. For this procedure, the SARTORIUS SECURA lab scale was used. But the post processing program can also handle readouts from the KERN PCB 6000 lab scale.
Figure 3.1: Schematic overview of the calibration setup.
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Jesse Hameete CHAPTER 3. CALIBRATION
The weighing system should be set up such that all the powder that falls from the disper-sion system is captured by the weighing system. In the current calibration, this is done by letting it fall in a glass beaker. The weighing system should be linked to a personal computer before beginning the measurements.
3.2 Calibration procedure
When the above mentioned precautions are taken, The calibration procedure can start.
Creating the calibration files
The steps to take in creating the calibration files are:
• Make sure the hopper is filled before beginning each experiment
• Start the dispersion system, wait until the mass flow is stabilized
• Note down the voltage of the thyristor and the intensity
• When the mass flow is stabilized, begin measurement
• Let the dispersion system run for 3 - 5 minutes without disturbing it
• Stop the measurement, save the data
• Repeat at least 3 times for each intensity
It is important that you repeat the measurements at the same voltage of the previous one, rather than trying to match the pin position on the thyristor. Also make sure that you save the data under the appropriate naming format: IXAY.txt, Where X is the Intensity and Y is the number of the measurement.
Post processing calibration files
When the calibration files are created, you should have at least three calibration files for each corresponding intensity. At this time, the matlab program CalibratePowder may be dropped into the folder that stores your calibration files. When the program is opened, the following parameters can be changed:
• Scale, choose if you have used a KERN PCB 6000 or a SARTORIUS SECURA lab scale by inputting ’KERN’ or ’SARTORIUS’ respectively.
• Readout, choose if you want your graph to plot the intensity against the mass flow rate or the voltage against the mass flow rate by inputting ’Intensity’ or ’Voltage’
respectively.
• fit, choose if you want the program to make a linear, quadratic or interpolation fit by
CHAPTER 3. CALIBRATION Jesse Hameete
When all the information is inserted, the program can run, and it will output the graph of your desire. In the current project, three different powders have been calibrated; Rio Tinto, TLS Technik & Sigma aldrich. The graphs of these powders can be seen in figure xxx.
Chapter 3 User Manual Dispersion system 9
Chapter 4
Operation of the dispersion system
This chapter describes the actions that are required to run dispersion system of the heat flux burner. Always ensure that there is sufficient ventilation and that the mass flow controllers (MFC’s) are calibrated.
The first step into using the dispersion system is making sure that the components of the system are secured and tight. The exploded view of the system can be seen in figure 4.1.
In this figure, it can be seen that there are quite some components that can get loosened or undone when the system is not used for a period of time. Therefore, it is advised to check the push-in connections of the venturi vacuum ejector and to check the tension of the bolts on the vibration system. On top of that, when the airtight box is being used, make sure that all the cable swivels are tightened. This ensures an optimal configuration of the system before use.
4.1 Filling the system
Filling the dispersion system with iron powder is done by removing the lid from the airtight container, and using the cone that is provided to pour the powder into the hopper. This is shown in figure 4.2.
CHAPTER 4. OPERATION OF THE DISPERSION SYSTEM Jesse Hameete
Figure 4.1: Schematic figure displaying the exploded view of the system
4.2 Controlling the airflow
A LabVIEW program was constructed that can control the airflow of up to four mass flow controllers (MFCs). For the purpose of controlling the airflow to the heat flux burner, only three mass flow controllers are used.
In figure 4.3, the User Interface can be seen. The first step is to load in the calibration data.
This can be done in section 1. For this purpose, a text file where calibration data can be entered and uploaded is provided. Once the calibration data is loaded into the program, the program can be run. In section 3, the maximum value of the MFCs can be entered, this makes switching out an MFC as easy as replacing the calibration data and switching the maximum value. From here, the setpoint of the different MFCs can be inserted manually. If the user wishes to let the program calculate the setpoint, the button ”Use ER?” in section 2 should be pressed. When this button turns green, the program automatically calculates the desired setpoints given a velocity, vacuum flow percentage, equivalence ratio (ER) and a
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Jesse Hameete CHAPTER 4. OPERATION OF THE DISPERSION SYSTEM
Figure 4.2: The hopper is being filled with powder using the provided cone.
Figure 4.3: Graphic User Interface of the LabVIEW program.
CHAPTER 4. OPERATION OF THE DISPERSION SYSTEM Jesse Hameete
Lastly, section 4 shows the setpoint of the different MFCs in percentages and in voltage (1-5V), along with the feedback from the MFCs. This feedback enables an accurate reading of the accuracy of the MFCs.
At this time, the equivalence ratio is used solely as the methane-air equivalence ratio. The equivalence ratio that corrects for the use of iron flow, as well as a LabVIEW program that allows the user to control the iron flow, is expected to be added in the future.
4.3 Controlling the powder flow
The flow of powder is controlled by the vibrator which, in it’s turn, is controlled by the thyristor. Figure 4.4 shows the thyristor regulator a multimeter. This is part of the setup which allows for a better repeatability as was shown in figure 2.1. The thyristor’s main component is a potentiometer with a set limit from intensity 1 to 10. The white triangle on the potentiometer allows an easy reading of the intensity. The required powder flow can be obtained by looking at figure 4.5. These lines display the relation between the mass flow of powder and the voltage. Next, turn the potentiometer to the intensity that gives the required voltage, and powder should begin to flow.
At this moment, only the Rio Tinto powder (Figure 4.5a) and the TLS Technik powder (Figure 4.5b) have been calibrated. For the calibration of more powders, review chapter 3.
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Jesse Hameete CHAPTER 4. OPERATION OF THE DISPERSION SYSTEM
Figure 4.4: Thyristor regulator with a multimeter as it is used in the dispersion system.
(a) (b)
Figure 4.5: Calibration data for the 2 powders that were considered in this experiment, the Rio Tinto powder (a) and the TLS technik powder (b).
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