The all new DiSCmini is a portable sensor for the measurement of particle number and average diameter, based on the electrical charging of the aerosols. The small size of the DiSCmini handheld makes the instrument particularly suitable for personal carry-on measurement campaigns.
Negative health effects due to nanoparticles appear to correlate particularly well with number concentration or surface. Epidemiological and toxicological studies are still mainly based on total mass, or they use fuzzy proxies like 'distance from a busy road' to describe personal exposure, although the health-related effects of particle number concentration are well known. We believe that this contradictory situation is due to the lack of adequate sensors on the market.
This gap is now closed with Testo´s handheld version of the “Diffusion Size Classifier”, DiSCmini. The DiSCmini is a portable sensor for the measurement of particle number and average diameter with a time resolution of up to 1 second (1 Hz). The simultaneous capture of number concentration and particle size allows the specification of other characteristic parameters, such as the particles surface (Lung Deposited Surface Area, LDSA). The instrument is battery powered with a lifetime of up to 8 hours; data can be recorded on a memory card, and transferred to a external computer via USB cable.
DiSCmini is particularly efficient for personal exposure monitoring in particle-loaded work space with toxic air contaminants such as diesel soot, welding fumes, or industrial nanomaterials.
DiSCmini is based on the electrical charging of the aerosols. Positive air ions generated in a corona discharge are mixed with the aerosol. The charged particles are then detected in two stages by electrometers. The first detector stage is a pile of steel grids; small particles will preferably deposit on it by diffusion. The second stage is a high-efficiency particle filter which captures all the other particles. The mean particle size can be obtained by analysis of the two currents measured on the stages. The particle count is determined with the total current. DiSCmini detects particles ranging in size from 10 to about 500 nm, while the modal value should lie below 200 nm. The concentration range is from about 1'000 to over 1'000'000 particles per cubic centimetre. The accuracy of the measurement depends on the shape of the particle size distribution and number concentration, and is usually around 10-15% compared to a reference CPC. The unit should be serviced and calibrated once a year.
Unlike other instruments DiSCmini needs neither working liquid of any kind nor radioactive sources. Therefore, it can be operated in any position and over extended periods without requiring a liquid refill. Typical applications include the determination of personal exposure in particle-loaded jobs (diesel soot, welding fumes, industrial nanomaterials) or in vulnerable groups (asthmatics, COPD patients). The development of large area survey grids of ambient air is becoming possible. The small size of DiSCmini makes the instrument particularly suitable for personal carry-on measurement campaigns. The high measurement frequency of 1 Hz allows the instrument to monitor rapid changes in the aerosol. This feature is particularly interesting to local or defined sources of particle generation. The equipment is designed for situations and applications where quick and easy access to particle number concentration and average diameter is desired.
Nanoparticle measurement anywhere.
It already exists.
testo DiSCmini operates without working fluids or radioactive sources and works in any orientation.
The Diffusion Size Classifier miniature DiSCmini is a handheld sensor for the measurement of nanoparticle number, average diameter and lung-deposited surface area LDSA with a time resolution of up to 1 second (1 Hz). The measuring principle is based on electrical charging of the aerosols. The small size of the DiSCmini makes the instrument particularly suitable for personal carry-on measurement campaigns. The instrument is battery powered with a lifetime of up to 8 hours; data can be recorded on a memory card, and transferred to an external computer via USB cable.
testo DiSCmini is the smallest instrument capable of nanoparticle number measurement available today, with a patented sensor, working in any orientation.
The handheld “Diffusion Size Classifier“ can be used for personal exposure monitoring or quick walk-through surveys of an area of interest, such as a workplace, or an urban area with heavy traffic.
Suited for all applications where ease of use is important
- Personal exposure monitoring
- Workplace hazard identification
- Filtration efficiency verification
- Air pollution mapping with one mobile or multiple stationary instruments
- Mean particle size: 10 to 300 nm (modal diameter)
- Particles counted: 10 to 700 nm
- Particle concentration:
- Detectable particle concentrations depend on particle size and averaging time.
- Typical values are given below.
- 20nm: 2E3 to 1E6 pt/ccm
- 100nm: 5E2 to 5E5 pt/ccm
- ±30% in size and number typical;
- ±5E2/ccm absolute in number
- Flow rate: 1,0 L/min ±0,1 L/min
- Operating conditions:
- Pressure: 800 to 1100 mbar abs ambient; Δp max. at inlet: ±20 mbar
- Temperature: +10 to +30 °C; relative humidity <90 %RH
- Time resolution: 1 second
- Dimensions: 120 x 80 x 40 mm
- Weight: 0.7 kg
- Power requirements: The battery charger is compatible with the any 100-120 volt or 200-240 volt 50/60 Hz AC wall outlet
- Battery lifetime: 8 hours typical; varies with ambient temperature. Charging time 2-4 hours depending on charger and status of battery.
Compared to a CPC, testo DiSCmini is truly handheld, easier to use and it delivers not only the particle number concentration but also average particle diameter and lung-deposited surface area. testo DiSCmini measures size particles smaller than about half a micron in diameter.
Due to its small size and low weight, the testo DiSCmini can also be used easily for airborne measurements.
The internal charger can be turned off, and the DiSCmini will then operate as the world‘s smallest aerosol electrometer.