SKC DT11 8ST Plastic Cyclone User Manual
- November 12, 2023
- SKC
Table of Contents
**SKC DT11 8ST Plastic Cyclone User Manual
**
This instruction sheet covers the following sampler models:
- 225-69: Cyclone sampler with re-usable cassette for 25mm diameter filter
- 225-69-37: Cyclone sampler with re-usable cassette for 37mm diameter filter
Introduction
The cyclone sampler is designed for dust (aerosol) sampling to the respirable
convention as defined in standard EN481:1993.
Design flow rate is 3.0 l/min, giving a 50% sampling efficiency (cut point) at
4.0µm (micron) particle size.
The cyclone sampler has been tested in accordance with EN 13205 by the Health
and Safety Laboratory (HSL) to verify its performance against the respirable
convention.
A certificate of conformity detailing the results of this testing is included
on page 4 of this instruction.
The SKC plastic cyclone is manufactured from conductive plastic which
dissipates electrical charges to the surrounding atmosphere and prevents
static interference on the collection of the dust particles.
The filter is held within a re-usable plastic cassette, which is supplied
complete with a metal filter support grid and a sealing clip to prevent
contamination of the sample during transport for laboratory analysis.
For detailed instructions on air sampling in general and use of the cyclone
sampler in particular refer to SKC’s 224-G1 Step by Step Guide to Air
Sampling.
It is also recommended to obtain and read the document MDHS 14/4 “General
methods for sampling and gravimetric analysis of respirable, thoracic and
inhalable aerosols”, available from the HSE website
www.hse.gov.uk, before carrying out any sampling
using the cyclone sampler.
Preparing the Cyclone Sampler for Use
The following instructions give basic details on how to prepare for sampling
by gravimetric analysis according to MDHS 14/4.
Select two filters from the same box or batch. One filter is used whilst
calibrating the sample flow rate and is then discarded, and the other is pre-
weighed to carry out the actual sample.
It is recommended to wear powder free gloves and to use tweezers when handling
filters in order to prevent contamination prior to taking the sample.
Loading the cassette
Ensure that the cyclone sampler components are cleaned of any contamination,
using a detergent solution. Allow the components to dry fully before use.
Referring to Figure 1 on page 2, place the top part of the cassette
(labelled “TOP”) upside down on a flat surface.
Place the metal filter support grid into the top part of the cassette. Place
the filter to be used for calibration onto the support grid.
Fit the bottom part of the cassette onto the top part and press down gently on
the edges of the bottom part to close the cassette.
Avoid exerting undue pressure on the filter. The closure is intentionally
stiff to avoid accidental opening, and to ensure a leak tight fit.
Fitting the cassette into the cyclone sampler
Referring to Figure 2, ensure that the large O ring is fitted to the
sampler body beneath the sampler insert and the small O ring is fitted over
the short tube in the middle of the insert.
Fit the assembled cassette into the cyclone insert with the cassette top
upwards.
Check that the thin O ring is fitted into the recess in the underside of the
sampler top. Place the sampler top on the cassette. Fit the retaining ring
over the sampler top and screw down firmly to secure the cassette within the
sampler and seal the cassette inlet and outlet. Ensure that the grit pot is
securely fitted over the ridge around the bottom of the sampler body.
Flow Calibration
Connect the inlet hosetail of the sample pump to the air outlet of the cyclone
sampler with a length of flexible tubing. Connect the flow calibration device
(such as a chek-mate flowmeter or rotameter) to the air inlet of the cyclone
sampler using a second length of flexible tubing.
Calibrate the sample flow rate to 3.0 l/min.
Disconnect the tubing from the cyclone sampler inlet and outlet. Remove the
cassette from the cyclone sampler.
Hold the cassette upside down and prise the two halves apart using the side
tab.
Remove and discard the calibration filter. Place the pre-weighed filter to be
used for the sample, onto the filter support grid and re-assemble the
cassette. Fit the cassette into the cyclone sampler.
Quickly re-check the flow rate and make any final adjustments. Switch the
sample pump off.
The cyclone sampler is now ready for sampling.
After Sampling
Away from the sample location quickly check the sample flow rate, then
disconnect the tubing from the cyclone sampler air inlet and outlet.
Carefully remove the cassette from the cyclone sampler and split the two parts
of the cassette apart.
Post Weighing the Filter
Carefully lift the filter out of the cassette using tweezers. Post weigh the
filter. The difference between the pre and post weights will give the
respirable sample.
Transportation
If further analysis is required, prepare the sample for transportation to the
laboratory by carefully placing the filter back in the cassette, and fitting
the yellow, U shaped sealing clip over the cassette inlet and outlet holes.
Use of the sealing clip prevents unwanted ingress or loss of contaminant
during transport. Alternatively, a filter transport cassette (SKC P/N
225-67-10) can be used, freeing the filter cassette for immediate re-use.
Certificate of Conformity
Testing carried out according to BS EN 13205 SKC plastic cyclone sampler for the respirable aerosol fraction defined in EN481 Tested at the Health & Safety Laboratory, Harpur Hill, Buxton SK17 9JN.
31/08/2018
Blas Map
SKC plastic cyclone operating at a flow rate of 31/min
Measured Mean Penetration
This certificate of conformity indicates that the plastic SKC cyclone sampler was tested at the above establishment on the designated date and that it complied with the Bias Performance Criteria (described in BSEN 13205) ata flow rate of 3 l/min in which 85% of the calculated biases were within +/- 10% of the theoretical respirable curve given in EN 481.