What you learn today
- Burst pressure of tanks
- Vent overpressure
- Mind the temperature
A tank looks sturdy. But it has a limit, and that does not only depend on how much you pump into it but also on how warm it gets.
Burst pressure of tanks
According to the device data:
| Vessel | Volume | Limit |
|---|---|---|
Small tank (StructureTankSmallInLine) | 6,000 L | 60,795 kPa |
Large tank (StructureTankBigInLine) | 50,000 L | 60,795 kPa |
| Gas pipes | 10 L per piece | 60,795 kPa |
| Liquid tanks and pipes | – | 6,079.5 kPa |
| Gas canister | 64 L | 10,132.5 kPa |
| Smart gas canister | 64 L | 20,265 kPa |
What counts is the difference to the pressure outside. From 80 % of the limit the vessel is under stress, above the limit it takes damage and finally bursts. For a gas tank the 80 % mark is at 48,636 kPa.
Venting overpressure
Two thresholds with a gap: filling goes up to 35,000 kPa, from 45,000 kPa an emergency vent opens, for example a pump into a second tank or to the outside. It only closes again below 40,000 kPa. While it runs, nothing is filled – otherwise two pumps work against each other.
Minding the temperature
A gas in a closed tank has constant moles. If the temperature rises, the pressure rises in the same proportion: p₂ = p₁ · T₂ / T₁. A tank at 40,000 kPa at 260 K has about 49,700 kPa at 50 °C (323.15 K) – above the 80 % mark without anyone refilling.
mul tmp press T_HOT
div tmp tmp temp
sgt tmp tmp STRESSSo the chip calculates what the tank would have at the hottest expected temperature and warns right now. On Mars the difference between night and noon is large, on Vulcan even larger.
[!NOTE] Since 0.2.6428 the tank itself has no logic: its kit builds an in-line tank that belongs to the pipe network like a piece of pipe. That is why you measure with a pipe analyzer (StructurePipeAnalysizer) on the tank line. It shows the values of the whole network, tank and pipes together.
If the analyzer is missing, the pressure is NaN. Filling and venting go off, the warning light on. A tank the chip cannot see does not get filled.
Diagram
Exercise
Task
The small tank is filled by the pump “Fuellung”, measured at the pipe analyzer “Wasserstoff” on the tank line: on below 30000 kPa, off from 35000 kPa. The pump “Ablass” runs from 45000 kPa and stops below 40000 kPa; while it runs, nothing is filled. The light “Warnung” is on when the pressure at 323.15 K would be above 48636 kPa (p · 323.15 / T) or the tank is missing.
Hints
Hint 1
Fill: slt/and with FULL, slt/or with REFILL.
Hint 2
Vent the other way round with sgt; then combine fill with “not vent”.
Hint 3
Warning: mul tmp press T_HOT, div tmp tmp temp, sgt with STRESS, plus NaN.
Quiz
5 questions. You pass from 60 % – the server does the grading.
Complete the day
- Passed the simulator exercise
- Passed the quiz with at least 60 %
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