Camfil Farr scanning electron microscope

C a m f i l Far r

Technical brochure

C a m f i l Far r scanning electron microscope C a m f i l Far r – clean air solutions

Camfil Farr Analysis system

what is in the air that you breathe?

In 1992, in collaboration with

then, Camfil has analysed more

the

at

than 1.2 million litres of air using

Camfil

this system. With its scanning

Farr launched a research project

electron microscope, Camfil can

aimed at increasing our know-

make available its knowledge of

ledge of the particles that are

air filtration and extensive experi-

present in the air and how they

ence of air analyses with the aim

affect our health. As a result of

of checking the quality of the air

this project, a sampling system

you breathe.

Wallenberg

Stockholm

laboratory

University,

for air analyses was developed. Today, this method has been This sampling system is based

further

on analysing particle content and

scanning electron microscope is

size using a scanning electron

now also used for other types of

microscope and an associated

analysis.

X-ray spectrometer. The method has been adapted for studying various types of particulate contaminants outdoors, in ventilation systems and indoors. Since

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developed

and

the

Camfil Farr Analysis

the scanning electron microscope

In a scanning electronic microscope (SEM), the sample to be studied is bombarded with highenergy electrons, which results in various physical phenomena. Some electrons are reflected back and can then be detected and give rise to an image. At the same time, the atoms in the sample are affected by electrons in the inner shell being excited, in other words, jumping to an outer electron shell. When they later fall back to the inner shell, an X-ray (a radiation beam) is emitted from the sample, which can be detected using an EDS detector. This radiation is specific to each chemical element contained in the sample, enabling chemical information to be obtained from the various

by the sample, it is also possible to analyse the composition of individual particles in terms of different chemical elements. The particle composition of the sample indicates whether, and if so where, there is a problem in the ventilation system.

particles of the sample. What can we see using an SEM? Using a scanning electron microscope, very high magnifications can be achieved that would not be possible with an ordinary microscope. The image on the right was taken with Camfil’s scanning electron microscope at a magnification of 42000x. In order to show a surface measuring 1x1 cm at this magnification, more than 15 million images of this kind would be required. The high magnification gives sharp images which act as visible proof of your air quality. The particle content, surface structure, size and shape can all be studied. The smallest particles which become attached to the sampling membrane and that are investigated using the microscope are less than 0.1 µm in size. These are known as nanoparticles. By utilising the X-ray signal emitted

EDS detector EDS-detektor

SEM detector Electron beam

SEM-detektor

Elektronstråle eeRöntgenX-ray beam stråle

Partikel Particle Filter

e-

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Camfil Farr Sampling

comfort ventilation – protecting people

The Camfil scanning electron microscope is used to analyse four main types of sample: air samples taken using a vacuum pump, air samples from a Camfil IAQ screening box and filter and dust samples.

Sampling using a vacuum pump

Sampling using a vacuum pump

or being generated in the filter

This sampling method involves

duct. Indoor air is also often sam-

using a vacuum pump contai-

pled using this type of sampling

ning a millipore membrane with

method in order to see how it is

holes that are 0.4 µm in diameter.

affected by the filtration process.

When air is sucked in through

Measuring filter Incoming air Vacuum pump

the

vacuum

pump,

airborne

particles larger than approximately 0.1 µm are trapped by the membrane. The filter is sent to Camfil’s laboratory, where the

Measuring filter

Outgoing air

native to sampling with a vacuum pump. The box is supplied readyto-use by Camfil and placed somewhere in the room in which

under

the air quality is to be checked.

the

scanning

electron

microscope.

All that needs to be done is to are

taken

simul-

press a button at the start of

taneously of the outgoing and

the working day in order to start

incoming air, in other words,

the sampling process. This will

upstream and downstream of a

automatically be concluded after

supply air filter. This gives a clear

eight hours, giving a represen-

picture of how effectively small

tative picture of the air that you

being filtered out. At the same time, it is also possible to identify whether larger

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box can now be used as an alter-

by the membrane are studied

particles in the outgoing air are

Camfil IAQ screening

A recently developed sampling

particles that have been trapped

Samples

Sampling form

Camfil IAQ screening

particles are bypassing the filter

breathe during a working day. This method is silent, simple, flexible and gives visible proof of your air quality.

Birch pollen

Filter samples

Filter samples The microscope can also be used to analyse samples from a filter. This could, for example, be relevant in order to evaluate a problem with filter media or to study the quantity and type of particles that are being trapped in a filter. Dust samples The final type of sample that is analysed in a scanning electron microscope is dust. This process is used to identify unknown dust that is found indoors or in filter ducts.

Dust samples

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Camfil Farr Report

summarising analyses

The report Following

completion

of

the

analysis, the results are summa-

A recently developed system can

rised in a report consisting of

be used to automatically find all

five sections:

the particles in one area of the

• An assessment of the particle content and remarks concerning the particle content of each sample.

sample and then analyse them using the EDS X-ray analysis system. Based on the information that this gives concerning the

• Information collected in connection with the sampling process.

chemical

• Overview images of the particle content of each sample.

This results in a list of the number

• A table of information concerning the types and quantities of larger particles that were found in the sample.

consist of plaster, rust and salt,

• EDS analyses and images of interesting particles.

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Automatic particle identification

composition,

each

particle is classified into one of several

predefined

categories.

of particles in the sample that for example.

Example

Outgoing air, sample 1

Leak in a ventilation system Camfil Farr Hi-Flo F7 In an office building, a routine check was carried out on the ventilation system in connection with the annual filter change. The system was cleaned Magnification: 250x

Magnification: 5000x

and the filters were replaced with new ones. The first sample indicated that the particle content in the incoming air was the same as that in the outgoing air, which led to suspicions of a leak in the ventilation system.

”

Incoming air, sample 2

Every day, we breathe in around ten kilograms of air.

Outgoing air, sample 1

The second sample indicated good filtration of the air with considerably lower concentrations of particles in the incoming air than in the outgoing air.

Magnification: 250x

Magnification: 5000x

Conclusion It was concluded that the measures that had been taken were sufficient, with the result that the in-coming air was being filtered effectively.

Incoming air, sample 2

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O n wor ld standards...

air technology and energy efficient air filter solutions with product development, R&D and local representation in the Americas, Europe and Asia-Pacific region. We supply high quality products and services with the aim of making our customers operations more sustainable, energy efficient and productive. Our own vision of sustainability is a global approach combining consideration for people, environmental protection and business performance. Camfil Farr is a member of the United Nations Global Compact programme and follows the GRI sustainability reporting framework.

www.camfilfarr.com FOR FURTHER INFORMATION PLEASE CONTACT YOUR NEAREST CAMFIL FARR OFFICE. YOU WILL FIND THEM ON OUR WEBSITE.

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