Taking A Sample
: USING GRESHAM GAS/AIR SAMPLING
All procedures in operation on the site relevant to monitoring and control must be adhered to. If sampling is to take place in a confined space, work systems as defined in HSE Guidance Note GS5 "Entry into confined spaces" must be followed.
All procedures in operation on the site relevant to monitoring and control must be adhered to. If sampling is to take place in a confined space, work systems as defined in HSE Guidance Note GS5 "Entry into confined spaces" must be followed
Remove Dust Cap from Cylinder Head.
Check Sample Cylinder is empty by depressing Schrader Valve in the Cylinder Head against the Pump Handle Retaining Bolt Head.
3) Plug the Sample Cylinder into the Bayonet Adaptor on the Pump. The Filling Indicator (if being used) is fitted between the Pump and the Sample Cylinder.
The Cylinder should now be purged by pumping
up to pressure several times and releasing the
contents of the cylinder as in 2 above. With
Double Ended Cylinders the Purging Attachment
can be used. The Attachment is fitted to the "free" end
of the cylinder and the pump "pumped" several
times to enable sample to flow through to atmosphere.
The Attachment is removed before the sample is
The sample is now collected by "Pumping" the
Pump until the required pressure of sample is
obtained within the Sample Cylinder. This can
be monitored by using the Filling Indicator or
by counting the number of Double Strokes, (Push/Pull),
of the Pump that have been made. As a guide the
table below shows the number of Double Strokes
required to obtain a sample of 14 bar (200 psi)
in the different size Sample Cylinders available.
THE PRESSURE MUST NOT EXCEED 17bar (250 psi).
|Cyl Capacity (ml)
|No Push Pull Strokes
using the Filling Indicator the number of strokes
shown above will register the gauge approximately
mid-way in the green section.
When the sample has been taken the Sample Cylinder
is unplugged from the Pump and the Dust Cap replaced.
The Sample Cylinder now contains the sample ready
In the laboratory the Sample is released from
the Cylinder using a Cylinder Testing Unit.