AUTOFLAME Mk8 MM, Technical Manual

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1 Sensors
Page | 15
MM Application Possibilities
1.1.3 Calculating Proving Time and Pressure Change
The following formulae may be used for calculating the proving time and pressure change allowed.
They are based on DVGW requirements of a leakage rate of 0.1% of the maximum volume flow.
Valve Proving Time:
𝑉𝑉𝑉𝑉𝑉𝑉 = 4 × ��
𝑙𝑙𝑉𝑉 × 𝑃𝑃𝑃𝑃
𝑀𝑀𝑉𝑉𝑉𝑉 ÷ 1000
� + 1 �
Vpt Valve proving time in seconds.
Ip Inlet pressure in millibars.
Pv Pipe volume in litres (volume = πr
2
x length, total volume of any interconnecting
pipe between valve seals)
Mtp Maximum gas throughput in litres per hour.
Pressure change:
𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃 𝑐𝑐ℎ𝑎𝑎𝑎𝑎𝑎𝑎𝑃𝑃 = 0.25 × 𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑎𝑎𝑎𝑎𝑙𝑙 𝑁𝑁𝑎𝑎𝑙𝑙𝑃𝑃𝑉𝑉 𝑉𝑉𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃 ( 𝑁𝑁𝑚𝑚𝑎𝑎𝑃𝑃 )
Example
Valve proving time:
Inlet pressure = 50mBar
Pipe volume = 5litres
Max gas flow = 100,000litres per hour
𝑉𝑉𝑉𝑉𝑉𝑉 = 4 × ��
50 × 5
100,000 ÷ 1000
� + 1 �
𝑉𝑉𝑉𝑉𝑉𝑉 = 14 𝑃𝑃𝑃𝑃𝑐𝑐𝑃𝑃
Set option 132 = 15 seconds.
Set parameter 132 = 15 seconds.
Note: option 132 is set in increments of 5 seconds, values must be rounded up.
Pressure change:
Inlet pressure = 50mBar
𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃 𝑐𝑐ℎ𝑎𝑎𝑎𝑎𝑎𝑎𝑃𝑃 = 0.25 × 50 𝑁𝑁𝑚𝑚𝑎𝑎𝑃𝑃
Set Option/Parameter 133 = 12.5 mBar
Note:
This is a metric formula, therefore imperial units must be converted before applying this calculation.
To convert PSI to mBar multiply the PSI value by 68.94.
To convert Cubic Feet to Litres multiply the Cubic Feet value by 28.31.
To convert Cubic Feet per hour to Litres multiply your Cubic Feet per hour value by 28.31.