This is the comprehensive User's Manual for the VSParticle Generator One Spark Generator (VSP-G1). The Quick Start Guide is available as a quick reference for standard operation and maintenance of the VSP-G1 unit.
VSParticle Generator One
VSParticle Molengraafssingel, 10 2629JD Delft The Netherlands info@vsparticle.com www.vsparticle.com
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The VSParticle Generator One Spark Generator (VSP-G1) is designed for researchers ("operators") studying material properties who want to easily produce inorganic nanoparticles from conductive materials. Ease of use allows the operator to control the size of nanoparticles (1 atom to 20 nm) and production rate (xx – xx). The operator can use different gases and electrode materials, comprising pure or composite materials, for a wider range of combinations. The closed system is designed for high purity with an inner chamber containing no polymers near the ablation zone. Gas-based production eliminates the need for chemicals/surfactants or precursors. The reactor can easily be customized to allow cross flow, co-flow, through flow (standard) and combined configurations.
The production rate depends on the energy input into the spark, and material properties of the electrode. The VSP-G1 has a maximum operating power of 60W, which corresponds to ablation rates up to ~100 mg/h for e.g. Au. Particle size is a function of the production rate and the flow rate. The spark gap is controlled automatically, allowing continuous operation. The spark generator is designed for a broad operating window, making it suitable for applications ranging from cluster research to materials science.
The closed system provides a safer production of nanoparticles and can easily be dismantled for safe transport of produced nanoparticles as well as for system cleaning and maintenance. Periodic cleaning and replacing of electrodes can be easily performed by the operators with a safe, simple and fast (<20 mins) protocol.
The output of the system consists of a gas stream filled with particles, with no polluting by-products formed during production. The particles are made available as an aerosol, allowing the operator to choose a suitable deposition method for his or her substrates. VSParticle can help select/develop a deposition system fitted to your specific needs.
The portability of the VSP-G1 system allows it to be integrated into a larger system for more complex operating procedures.
How to use this manual
This user's manual provides instructions for the set-up, installation, operation and maintenance of a VSP-G1 unit. Before operating the VSP-G1 unit, please read the manual with careful attention to the safety section and to the warnings provided throughout the manual, indicated by the following symbols:
Warning information.
(Short index of manual and a 1 sentence summary of each chapter/section)
A quick start guide is also included for faster set-up as part of the standard operating procedure. For more information regarding safety and more complex operations as well as troubleshooting and maintenance, please refer to this manual.
System and Operator safety
top[Use this as part of a general introduction in the appendix. The introduction in the User's Manual should be/comprise a summary of that appendix]
Aerosolized nanoparticles are formed in a spark generator after a high voltage spark evaporates part of two metallic electrodes. This method is flexible with regards to the composition of the nanoparticles. The resulting nanoparticles are carried in a flow of gas, where they can be manipulated and/or transported, before depositing them onto a substrate.
The VSP-G1 spark generator is designed as a continuous source of aerosolized nanoparticles for use in a controlled process system. This controlled process system typically comprises a gas source, a gas tight system of unit operations, valves and tubing, and a gas exhaust fitted with one or more particle filters. Typical conditions in the process system are room temperature and ambient pressure. The system can be run at slight over- or under-pressure.
Intended use of the VSP-G1
Do not exceed +0.4 bar. Do not turn on the spark below -0.4 bar.
ASK TC HOW TO ADD BORDER COLOR TO TABLE ABOVE... CODE DOESN'T SEEM TO WORK??
Intended use of the VSP-G1
The VSP-G1 is not intended for use with reactive gases, in particular gases containing more than a few percent oxygen, such as air.
The risks associated with a spark generator can be divided into two categories: those associated with the machine itself, and those associated with the nanoparticles. Machine-related risks are more widely regulated by international norms, such as the European conformity system required for marking certain products with the CE symbol. Synthesized nanomaterials are relatively new and their quantum properties are still being studied. For this reason, nanomaterials are precautionarily considered highly toxic materials. Due to the fact that little is known about nanomaterials, safety measures for working with, storing and transporting nanoparticles have been primarily drawn from those designed for fine particles.
Safety of machinery
The VSP-G1 spark generator comprises general electronics (<50V), gas connections and high voltage (6kV), as well as moving parts. Several safety mechanisms mitigate the risk for damages and incidents related to potential equipment failure, but primary responsibility for correct and safe operation lies with the user of the system. The VSP-G1 is intended for use by qualified personnel only.
Operator safety actions
The operator is required to ensure that:
the reactor is correctly mounted (see flow configurations); set hyperlink
there are no objects near the electrodes (see flow configurations); set hyperlink
process connections are correctly made (see process connections); set hyperlink
the pressure in the system is limited to 0.4 bar (see process connections); set hyperlink
all, if any, external safety systems are functional (where applicable); and
personal protective equipment are being used correctly (gloves, glasses, and FFP3/P3 certified filter mask).
Safety mechanisms Interlock.
The interlock cuts power to the high voltage supply and the motor, shutting down particle production.
Gas connections and other user-provided functions are not controlled by the interlock.
Clearing interlock.
To clear the interlock state, the operator must first fix the conditions that caused the state change. Afterwards, press and depress both dials to clear the interlock.
Reactor interlock.
The VSP-G1 detects whether the reactor endcaps are properly mounted. The operator must ensure that the reactor itself is correctly assembled. In short, this means that the reactor is leak tight and the exposed electrodes and electrode tips are free to move with a minimum clearance of 10mm from any foreign objects.
External interlock. (option)
An external interlock switch can be provided for incorporation in an external safety system. To allow operation, two pins of the interlock connector must be connected (shorted). Breaking the connection switches the system into interlock mode.
Other residual risks
Pressure. Pressure within the closed system poses a serious risk when improperly handled. Increased pressure can possibly be caused by unintentional release of gas at high pressure, the closing of output valve while the input valve is open, clogged filters, spark obstruction, or a full deposition system. If the pressure within the (spark?) system were to reach 1.4 bar (0.4barg), the seals and gaskets could be compromised or the viewport could explode..
Non-ionizing radiation. The spark plasma emits a bright light in the visible and UV range. A viewport with a removable optical filter is included to allow visual inspection of the electrodes. Additionally, electromagnetic radiation (radio frequency) may be emitted.
Avoid damaging your eyes. The optical filter is designed to protect against the intense light of the spark. Do not remove the optical filter when running the spark.
Avoid damaging your eyes. The optical filter is designed to protect against the intense light of the spark. Do not remove the optical filter when running the spark.
The VSP-G1 comes with a specially coated viewport to screen electromagnetic radiation. Do not scratch the coating (see maintenance). Do not replace the viewport with a different type.
Noise emissions. When operating under full power, the VSP-G1 can generate noise levels up to TBD dB. MEASURE AND DETERMINE RISK.
Safety of nanoparticles
Because our spark generators can in principle be used to produce nanoparticles from any metal, we start from the assumption that they pose potential risks to the health of operators, consumers and to the environment. This manual addresses operator exposure. Consumer exposure is determined by the application in which the nanomaterials are to be used, and should be evaluated on a case-by-case basis by the user. Environmental considerations should also be addressed by the users with a life cycle analysis, briefly discussed below.
The main channels of user exposure to nanoparticles are through absorption, ingestion and inhalation. The aerosol nature of the produced nanoparticles by the VSP-G1 system presents more risk of exposure through inhalation. The respiratory system of the human body has natural defenses in place for airborne particles such as dust, viruses and bacteria, however, nanoparticles are able to bypass most of these defenses due to their small size. For this reason, nanoparticles are treated in the same way as fine particles. (see the end of this section for links to further information on health safety)
Operator exposure
While the VSP-G1 unit is designed to be a closed system to maximize safety when working with nanoparticles, there will be situations in which it will be necessary to open the system, including routine maintenance activities, replacement of electrodes and filters, and sample extraction. The list below also includes some possible situations in which the operator may be inadvertently exposed to nanoparticles and a brief summary of the necessary precautions to prevent, wherever possible, such situations.
Exposure risk
Precaution
Gas phase exposure
An aerosol system must be leak-tight from source to deposition. (see leak-tightness test protocol) Do not handle or open the system while particles are being generated and while gas is flowing.
Filtration
Particle filters are characterized by a drop in filtration efficiency for particles between ~100 and 300 nm. For <20 nm particles as generated by the spark, filter efficiency is typically >99.99%. The gas exhaust should be treated with a large capacity HEPA pre-filter, followed by an ULPA end filter.
Product handling
Our aim is to minimize handling of the powders themselves. The generated particles can be manipulated and deposited in an in-line manner, inside a closed system. However, it may occur that the system must be opened to insert or remove a substrate. In such cases, methods as described in Maintenance must be used.
Explosion risk and pyrophoricity
Metal nanoparticles can be extremely reactive, and can be pyrophoric (spontaneous ignition upon exposure to air). VSParticle does not recommend the use of air or other oxygen-rich gases for nanoparticle production in the VSP-G1 unit. Controlled air-exposure, however, is needed before opening the system in order to passivate any reactive materials. (see controlled-air exposure protocol)
Maintenance (opening the system)
Nanoparticles will collect on the surfaces inside the reactor and downstream piping. Cleaning of these surfaces presents the largest exposure risk to operators, unless they can be performed in e.g. a glovebox type environment. The maintenance protocol includes: 1, worker protection, i.e. gloves, masks, clothing, etc.; 2, flushing to remove any aerosolized particles; 3, controlled-air exposure to ensure passivation; 4, cleaning methods (wet cloth, containment of disposables); 5, disassembly sequence to minimize accidental exposure during maintenance; and 6, general disposal guidelines. (see System Care)
There is also a separate protocol for dismantling and sealing used filters for disposal/recycling. (see filter replacement protocol)
Life cycle analysis
The waste of the spark generator consists of the carrier gas plus any nanoparticles not deposited on the substrate but picked up when cleaning the reactor surfaces and the pre- and end-filters. These materials should be pooled, preferably separated by the elements in the waste, in order to recycle the metals. The carrier gases are typically inert Ar and N2, which can be vented (e.g. through a fumehood). If other carrier gases are used (toxic, greenhouse, etc), capture or post-treatment should be used to conform to general industry or laboratory standards on gas use.
Life cycle analysis for the end product should be evaluated by the user of the technology on a case-by-case basis.
Nanosafety Guidelines, a set of safety recommendations for working with ‘free nanostructured matter’ in research activities conducted within Dutch Universities
Nanosafety Quick Check, a checklist developed based on a summary of the Nanosafety guidelines listed above is there a link to this, or can we provide this as a downloadable file? permissions?
An abridged form of this section is also available as a Quick Start Guide.
Figure [x]: A basic setup connecting the input gas source and flow system to the particle source, deposition system, filtration system and the ventilation system.
Figure [x]: A basic setup connecting the input gas source and flow system to the particle source, deposition system, filtration system and the ventilation system.
[TC: IS THERE A CODE FOR AUTOMATICALLY RESIZING THE IMAGE BASED ON BROWSER SIZE? USEFUL FOR OPERATORS ACCESSING MANUAL USING TABLETS IN THE LAB]
The following standard operating procedure is for the basic setup pictured above, which comprises several operating units: a gas source and flow system, a particle source (the VSP-G1 unit), a pressure gauge, a deposition system and exhaust filters. To complete the setup, the units are connected with tubes, piping, fittings, valves and so on. The ball valves () in this setup help compartmentalise the overall system for leak testing and for safe disconnection. Each setup will be different, depending on your individual needs, but the concepts described here should generally be valid.
The leak tightness protocol [hyperlink] is an essential part of the operating procedure before initiating particle production.
Please read the entire procedure before using the VSP-G1!
Setup description To summarise our setup depicted above, the gas source is connected to a flow system that leads to the VSP-G1 unit (particle source) which is in turn connected to the deposition system. The deposition system is connected to the filter system and the filtered gas is safely vented via the fume hood.
Looking closer at the setup, we see that each unit within the setup is preceded and followed by a ball valve, with an addition of extra valves preceding and following the deposition system for ease of removal [insert info box about compartmentalisation in the right margin here]. In between the spark system and the deposition system is the pressure gauge (P) that allows us to ensure that the pressure within the system does not exceed +.4 bar. The deposition system is followed by a filtration system containing a HEPA (or better) filter which contains any nanoparticles that have escaped the deposition system filter, and the outflowing gas is vented through the fume hood.
Prepare the system for production
Design/draw your flow diagram.
Assemble the setup according to your specifications. (Ensure that the reactor is closed and mounted [hyperlink to Mounting the reactor in the Setup chapter] correctly!)
Check the connections.
Check the system for leak tightness and make adjustments if necessary. (See leak tightness protocol [hyperlink]) [insert note about pressure safety in the right margin here]
Start nanoparticle production
Check for leaks if any changes were made to the system (see step 4 of Prepare the system for production).
Power up all systems.
Ensure that the path to the exhaust is clear.
Begin gas flow.
Set target voltage and current using the dials on the VSP-G1.
Press the start button to begin production.
[Insert stabilisation note in the right margin]
Remove your sample When the deposition system is full or when you’ve produced the desired amount of nanoparticles,
Stop particle production.
Flush the system [hyperlink] (9 x τ).
Stop the gas flow.
Take out your sample following the procedure for your deposition system.
Figure [x]: Compartmentalising the deposition system for safe disconnection from the overall setup.
To remove our sample in the setup above, we stop particle production, flush the system [hyperlink] (9 x τ), close off the four valves surrounding the deposition system (see Fig.[x]) and disconnect the deposition system from the setup. We then take the deposition system, still closed, to the fume hood where we can proceed to remove our sample.
Nanoparticles are unique in the way that their size changes their material properties. These quantum properties are aided by the fact that the nanoparticles have greater surface area compared to their bulk form. This greater surface area allows [WHAT??] . As we continue to understand more about the quantum properties of nanoparticles, we can begin to appreciate the possibly endless applications of nanoparticles. If we look at the scientific literature published in the last five years, there are six major areas of scientific study focusing on the application of nanoparticles (FOOTNOTE: compiled using the Scopus database https://www.scopus.com/): Catalysis, Sensors, Electronics, Coatings, Energy and Health. The highest number of publications are from the fields of Catalysis, Health and Energy, with Energy research containing the most subfields. Another area not as widely studied as the six mentioned above includes the application of nanoparticles in lubrications to improve lubricant performance.
The subfields of nanoparticle application research within the six areas and their possible industrial [commercial?] applications include:
Field
Subfield
Possible applications
Catalysis
New catalysts
Atomic mixing enables the creation of completely new alloys and materials with improved catalytic activity.
Impregnation of supports
Spark discharge can be used to impregnate nanoparticle-sized catalytic support, which greatly improves surface area and has already been applied in catalytic converters in cars.
Sensors
DNA/RNA detection
By attaching small pieces of DNA or RNA to a MNP, the complementary piece of that DNA can be detected, which is useful in medical diagnostics or genetic modification.
Gas sensors
Sensors can be made much more sensitive by using MNP's and can be applied to many gases.
Bio-sensors
MNP's can be used to improve bio-sensors that detect organic compounds.
Electronics
Printed circuits
MNP's can be deposited in a pattern or lines to create electronic circuits.
Flexible electronics
The circuits are thin enough to be flexible and can be deposited on any surface, even fabrics.
Photodetectors
( )
Coatings
Functional coatings
Surfaces could be modified with MNP's to create a transparent, functional coating, which could produce energy, be self-cleaning or be hydrophobic.
Anti-corrosion coatings
Depositing layers of AlO makes the underlying metal more oxidation resistant.
Energy
Fuel cells
Integrating Pt or Pd NP's as catalysts in fuel cells could make them more efficient.
Solar cells
Using quantumdots in solarcells could make efficiencies possible above 40%.
Water splitting
Gold MNP's can improve photochemical water splitting.
H2 storage
Mg nanoparticles are a promising candidate for efficient H2 storage.
Li-ion batteries
Using NP's in batteries improves charging time and the lifetime of the battery.
Health
Anti-microbial coatings
Incorporating silver MNP's in fabrics makes the fabric anti-bacterial, a procedure that is relatively easy to do with spark discharge.
Cancer treatment
MNP's are being used in research for new cancer drugs and to improve chemotherapy.
In-vivo imaging
NP's can be used for medical imaging, as contrasting agents in MRI or other techniques.
Toxicology
Testing the toxicology of nanoparticles can be made faster and easier using spark discharge.
The value of nanoparticles lie in the quantum properties that enhance more tangible products, such as improving drug delivery methods at the cellular level or creating more efficient solar cells. However, the very same value, the quantum properties, are also their huge drawback at the industrial level - not much is known about the quantum properties. Some nanomaterial are perfectly safe, but other nanomaterial might be even more toxic. The industrial limitations of the use of proven-to-be safe nanomaterials, however, lie in the production process - most nanomaterials are desired for their purity and particular deposition state, thus it is cost-ineffective and time consuming to produce nanomaterials as a product to be used in a process rather than produce nanoparticles as a part of the production process where the nanomaterials are deposited directly where they are needed.
Overview of gas phase nanoparticle production
Nanoparticles come in different forms, from dendrimers and composites to carbon-based and metal-based materials, and can be stored in different media, from films to colloids and aerosols. There are different methods based on the form of nanoparticles desired. Meuller and his colleagues summarized the methods of gas phase production of nanoparticles in their review of spark discharge generators (2012), which included flame spray pyrolysis, spray protolysis, electrospray, evaporation/condensation of material and aerosol generation by spark discharge. All methods except for electrospray produce high purity nanoparticles with narrow size distribution at a high production rate. The well-proven electrospray method, which deposits the colloidal particles in a controlled homogeneous manner that minimizes residues where still present, has been in use for a longer time compared to other methods with readily available materials on the market. Both spray protolysis and spark discharge methods are simple and fast. The evaporation/condensation method offers detailed control over deposition parameters. The spark discharge method can easily be scaled up efficiently. The flame spray pyrolysis, evaporation/condensation of material and spark discharge methods all require higher amounts of energy. In the case of the evaporation/condensation of materials, the time and energy consumption required limit the overall operation time of the generation system. The spray protolysis and electrospray methods require the use of precursors and solutes, potentially contaminating the process. Flame spray pyrolysis requires postprocessing for the production of non-oxide nanoparticles. Depending on the desired end product or process, each method has their own set of advantages and disadvantages.
[POSSIBLY NOT NEEDED... SEE TEXT ABOVE]
Production method
Summary
Flame spray pyrolysis
High purity nanoparticles and narrow size distribution at a high production rate. Requires higher amounts of energy and precursors in most cases need to have physical properties that are not too dissimilar. Postprocessing is most often required for the production of non-oxide nanoparticles.
Spray protolysis
A simple and fast process for the production of high purity nanoparticles and narrow size distribution at a high production rate. Precursors and solutes are necessary, which potentially contaminate the process.
Electrospray
Deposition of colloidal particles in a controlled homogeneous manner that minimizes residues where still present. Precursors and solutes are necessary, which potentially contaminate the process.
Evaporation/condensation of material
Good yield and offers detailed control over deposition parameters. Furnace energy consumption and the longer heat up and cool down times of the furnace limit the overall operation time of the generation system.
Aerosol generation by spark discharge
Simple method that provides a reasonable yield of high purity nanoparticles with less contaminants involved in a process that can be easily scaled up. Requires higher amounts of energy.
Table based on Meuller, et al. (2012): 1256-7.
Aerosol generation by spark discharge [what's the difference between spark discharge and spark ablation??] [??spark ablation = Ablation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes. spark discharge = An electric spark is an abrupt electrical discharge that occurs when a sufficiently high electric field creates an ionized, electrically conductive channel through a normally-insulating medium, often air or other gases or gas mixtures.??]
From the perspective of researchers interested in studying material properties, the spark discharge method provides nanoparticles in a fast, simple manner that eliminates any other contaminants that prevent the study of the pure quantum properties of the nanoparticles. From an industrial (commercial) perspective, the spark discharge method provides a way of producing and depositing nanoparticles directly onto the final product, avoiding issues of transportation and stabilization of mass-produced nanoparticles.
History of the spark ablation technology How the spark ablation process works Research using spark ablation technology
Health Council of the Netherlands. Health significance of nanotechnologies. The Hague: Health Council of the Netherlands, 2006; publication no. 2006/06E. Available online. Set up to open in new window
Hoeneveld, D. et al. Nanosafety Guidelines. Delft University of Technology: NanoSafety workgroup of the Faculty of Applied Sciences, 2008. Available as downloaded document. Set up to open in new window
Meuller, B. O. et al. Review of Spark Discharge Generators for Production of Nanoparticle Aerosols. Aerosol Science and Technology (2012), doi: 10.1080/02786826.2012.705448.
Detailed communication set up
Configurations Command syntax Command list
VSP-G1 Technical specifications
Unit Specifications
Power
110-240V AC
Dimensions
Casing ca. 52x30x20cm
Reactor added height ca. 10cm
Weight
19kg
Gas inlet/outlet
10mm tubes (with Swagelok connectors)
Display
16x2 characters
Digital output
RS232
Operating Window
Flow rate
1-30 L/min
Gas
Supported: Ar or N2 (recommended purity 5.0) Unsupported: He, Ne, Xe, Kr Contact VSParticle for the use of reactive gases such as air and H2.
Electrode material
Comes with Cu electrodes. Various other metals (e.g. Ag, Au, Pt, W, Ni), semiconductors and carbon are possible.
Gas connections and other user-provided functions are not controlled by the interlock.
Do not handle or open the system while particles are being generated and while gas is flowing.
) in this setup help compartmentalise the overall system for leak testing and for safe disconnection. Each setup will be different, depending on your individual needs, but the concepts described here should generally be valid.
