Riken Keiki RS-400 Series, Operating Manual

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4 How to Tube 4-2. Precautions on tubing work
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The table below shows the guideline values for the "setting pressures of external pressure reducing
valves" and "bypass flow rates" corresponding to the "tubing diameters" and "tubing lengths" from the
external pressure reducing valve to GAS IN of the sampling device in the tubing system shown on the
previous page.
Use this table only for your reference because it shows estimated values for assumed arrival time of six
seconds or shorter, without any view for upstream tubing structure from external pressure reducing valve
or filters installed at any point of the tubing.
Tubing length
Tubing diameter
10m 20 m
Ø3, 1/8"
Setting pressure: 0.04 MPa
Bypass: Not required
Setting pressure: 0.2 - 3 MPa
Bypass flow rate: 2 - 5 L/min
Ø6, 1/4"
Setting pressure: 0.1 MPa
Bypass flow rate: 2.5 - 5 L/min
Setting pressure: 0.1 MPa
Bypass flow rate: 5 L/min
Ø8, 5/16"
Setting pressure: 0.1 MPa
Bypass flow rate: 5 - 10 L/min
Setting pressure: 0.1 MPa
Bypass flow rate: 10 L/min
Ø10, 3/8"
Setting pressure: 0.1 MPa
Bypass flow rate: 10 - 20 L/min
Setting pressure: 0.1 MPa
Bypass flow rate: 20 L/min
Use tubing with a large inner diameter for GAS OUT and RELIEF OUT.
Ø6 - 4 Ø8 - 6 Ø10 - 8
GAS OUT 5 m or shorter 25 m or shorter -----
RELEF OUT 0.5 m or shorter 4 m or shorter 10 m or shorter
4-2. Precautions on tubing work
1) Use stainless tubing.
2) After the tube is cut, its cut point may have a smaller inner diameter.
Use a file etc. to expand the inner diameter of the cut point.
3) Cut-dust of tubing may cause failures of the needle valve, flow rate detection mechanism, three-way
switching valve etc.
To remove cut-dust remaining inside of the tube, blow compressed air etc., into the tube before
connecting it to the calorimeter.
4) Determine a sampling point inlet for the measuring gas, considering the airflow of the measuring gas
line, unevenness in the manufacturing process of the fuel gas.
5) Adjust the measuring gas equivalent to the ambient temperature before supplying it to the sampling
device.