Accuracy and Product Quality

Environmental monitoring in cleanrooms, especially those associated to the Life Science industry, are a mission critical application.  Sampling systems that are prone to error or inaccuracy put business continuity at risk, as well as  public safety. 

Climet's corporate culture is not driven by profit, but instead we as a team take great pride in  providing the highest quality and most accurate instruments.  Simply, we compete based on quality, and this is where our competitive advantage lay.

Climet has been manufacturing portable particle counters since 1967, and units manufactured since 1993 still pass ISO 21501-4: 2007 without any modification to the hardware!  This is nearly 15 years before ratification of this international standard, and nearly 15 years longer than the competition.   

To be sure, no one is more experienced than Climet when it comes to aerosol particle counters!

The International Standards Organization (ISO) 21501-4, section 4.10 states"

Calibration at the calibration interval should include at least size calibration, size resolution, counting efficiency, and sampling volume uncertainty.

Climet particle counters meets or exceed all ISO 21501-4 calibration criteria, and Climet is the only manufacturer of particle counters that certifies our exhaust to ISO Class 3 emissions.  Although HEPA filters claim to be 99.997% to 99.999% efficient, we find this depends on the challenge.  In practice we have experienced numerous individual filter failures during pretest, and are extremely selective over what vendor we use for our HEPA filters. Climet does not simply use the low cost filter provider, and merely regurgitate a vendor's questionable filter efficiency.  To the contrary, extensive testing is made both during vendor qualification; as well as with each individual unit sold, and during factory interval calibration.

As it pertains to instrument accuracy, there are two key criteria:

50% Count Efficiency Test

Size Resolution Test

The first key criteria is the 50% Count Efficiency test.  In this test, particles are used to challenge the  sensor's response with particle sizes close to the minimum detectable reported size range, and another that is 1.5 to 2 times larger than the smallest channel.  The threshold of the particle size is set to the median of the particle distribution. In a 50% Count Efficiency test, half the test particles will fall below the threshold and will not be counted, while the other half of the test particles will exceed the threshold and be counted.

The ISO 21501-4 standard for the 50% Count Efficiency test is ± 20%.  Climet finds this level of accuracy completely unacceptable, and is the only manufacturer of particle counters that well exceeds the ISO standard.  New Climet products  and interval factory ISO calibrations are certified at less than or equal to ±10%, and offer our customers theortically twice the accuracy provided by the ISO 21501-4 standard.

The other count efficiency test is 100% Count Efficiency, which is a measurement of the laser alignment.  All particle counter manufacturers claim to meet the ISO standard of ±10%. 

The next key criteria as a measurement of accuracy is Size Resolution.  Resolution is a measurement of the particle counter's ability to accurately size particles.  This statistical equation is based on a Gaussian distribution.  Climet uniquely provides the industries highest resolution by use of a patented metal ellipsoidal mirror. Climet particle counters have no plastic laser or collection optics, and therefore do not suffer from a poor coefficient of thermal expansion and calibration drift.  Furthermore, our unique technology surrounds the air flow allowing the sensor to metaphorically view particles from virtually every angle.  This minimizes the effect of particle shape (or morphology) on sizing errors.  Additionally, our laser diodes are evaluated on three criteria:

Laser Life - Production and sensitivity to heat

Stability - Electronic jitter (e.g., instability) causes an optical response that results in false high counts.

Resolution - Looking to generate a line to cover the entire length and width of the air flow, and provide a narrow response to particles.  The extreme long life laser diodes touted by some particle counter manufacturers are not new technology, and are commonly used in fiber optic applications.  Climet's extensive testing of these laser sources has demonstrated a wide response to particles, resulting in poor resolution and sizing errors.

Climet laser diodes provide the optimal combination of long life, stability, and resolution that give our instruments unparalleled accuracy and assurance. The ISO 21501-4 standard for Size Resolution is <15%.  And, once again, Climet well exceeds the ISO standard with 4% to10% (typical).

Climet particle counters are distinctively the most accurate and reliable instruments available on the market today. Built to last twice as long as the competition (or more), our team is proud to manufacture a product that offers our customers the highest return on investment (ROI) and best value.



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Climet Instruments Company
A Division of Venturedyne, Ltd.

Tel.+1 (909) 793-2788 | Email:

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