MFS
The second passes from the chamber through the valve labelled "OFF/TEST" to the exhaust port.
This is a more direct route and takes the majority of the flow when the valve is in the "off"
position, avoiding an accumulation of water vapour in the flowmeter.
When the valve is in the "test" position this line is blocked, forcing all of the outlet flow thought
the right hand meter, and allowing a check to be made that the chamber sealing is good.
2.5 Gas Connections (MFS/4)
The nitrogen inlet connects to a manifold on the back cover (right hand side as viewed from the
front). This divides to four flowmeters TC1 to TC4, whose valves may be adjusted to set the flow
rate in accordance with the requirements of the test standard.
There is a single outlet for all four chambers on the right hand side of the oven.
By switching one of the four valves on the right hand side of the oven (labelled “____/TEST”) to
the TEST position, the outlet from the corresponding chamber passes through the flowmeter
labelled TEST. This allows a comparison of inward and outward gas flows for that chamber to test
for leaks. Each chamber can be tested in turn. To avoid moisture build up in the test flowmeter,
the test gas passed through a cooling coil on the right hand side; moisture collects in a trap which
should be visually checked and emptied by pushing up the small valve at its base.
The normal position of the four valves is in the “_____” position.
2.6
Desiccator (if supplied)
The optional desiccator is designed for separate use, and is not connected to the oven in any way.
It is used for cooling the sample. Gas inlet and outlet are provided so that a nitrogen can be passed
over the cooling sample.
3.0
4
MF14
