EOS - Equation of State
EOS is the abbreviation of Equation of State.
It shows the calculation mode:
• Real Gas - Tech Gas Blender – it considers the behavior of the gas according to the most advanced equations available in thermodynamics for Oxygen - Helium - Nitrogen mixtures:
• modified Benedict-Webb-Rubin and Helmholtz Equations of State (pure gas)
• Helmholtz Energy Equation (mixing rules)
The Real Gas option is highly recommended; using Ideal Gas you can have significant errors, in particular in mixtures with a high fraction of Helium and high pressure.
The Ideal Gas model was maintained for educational purposes and comparison only.
You can select your preferred decimal places to display.
The possibility to select more decimals is obviously due not to pursue greater precision but to allow the use of the program for educational purpose.
In some features the number of decimal places could be restricted by graphics requirements.
The calculation requires the final pressure to be taken at the same temperature as initial pressure.
In this section you can set the isotherm temperature.
This option allows to set the gas prices for Oxygen and Helium and to the preferred method of cost calculation.
In case you enter the nominal cost (storage bank volume * pressure), you have to be aware that this is not the actual cost, due to the gas compressibility.
If you want to know more about this topic go to "Tools", "Gas prices - nominal vs real".
Max Oxygen % in Continuous Flow
This option allows to set the maximum Oxygen percentage in the EANx/Trimix used to fill in Continuous Flow mode, typically 40%.
Since the user could have Oxygen Haskel or other oil free boosters, this field is not limited to 40%; it is the user's responsibility to enter a value according to the Oxygen hazards prevention (see "Blending - Safety precautions - a more advanced step").
That is why this check is limited to the Continuous Flow filling mode: if you declare a high fraction Oxygen Bank Mix, the software assumes you can manage this mix safely.
This option allows to customize your personal cylinders, so as to reduce the set of possible alternatives to those which are used frequently.
In fact, you can remove the default cylinders and create new ones; the result is that with one click you can choose what you want without the hassle of too much useless information.
When adding new cylinders, enter the description you want and the actual internal "floodable" volume (in liters) of the new cylinder in order to obtain accurate results when calculating the contents.
This option allows to customize your favorite mixtures, so as to reduce the set of possible alternatives to those which are used frequently.
In fact, you can remove the default mixtures and create new ones; the result is that with one click you can choose what you want without the hassle of too much useless information.
This feature allows you to select the mixture you want with one click on the list; alternatively you can directly edit the gas percentage fields and the list field will show the new mixture.
Current mix management
In case you need to vent the current mix, you might consider two additional options:
• Accepting a higher final pressure to achieve the requested target gas composition. This option only makes sense if you have tanks that support higher pressures (to be indicated in this form) compared to the target pressure requested (Trimix, Heliox and EANx).
• In Trimix mode only: adjust only the fraction of Oxygen, considering it the priority. This option will require a final pressure lower than that of the previous case (between the current mix pressure and the maximum set pressure in this module), but with a different composition of the two inert gases that will be displayed to allow you to assess the compatibility with your needs.
In case you need to vent the current mix and you select the option "Search for alternatives …", the software will calculate these possibilities, but they will be proposed only if the results fall between the set pressures in this form:
• Lowest target pressure: the lowest final pressure considered acceptable as ‘full bottle’ (ex. you need to vent to 170 bar, the software finds a solution at 190 bar but you set 200 as minimum final pressure: the solution is not shown.
• Maximum admitted final pressure: the maximum that is considered acceptable (of course, not exceeding the max tank pressure)
Set warning limits
In the Tech Mixtures Blender section, in the filling instructions screen-shot, you will find some mixture information, including the depth where this mixture will achieve some PO2 and END values.
In this section you can set and customize these warnings.
In this window you can set the print preferences about the cost.
In case you check “Print fill cost”, you can customize the print including:
• cost per cubic meter/ foot
• details of added gas (on top of the current mix) and total gas (the total content)
• added gas only
• total gas only
It allows to set the following units:
- ° C (Celsius)
- ° F (Fahrenheit)
- CF (Cubic Feet)
- Other (you can enter a string description, ex: CAD$)
- Pounds (lbs) – in the “Gas weight” Tool
That's not a Metric/Imperial option: each unit is unrelated to each other.
Ex.: you can set feet and bar at the same time.
You can also set the gas price in cubic feet and keep the application in liters.
Available interface languages - English and Italian are available
The first time you run the program it will check the Operating System language: in case it is in Italian then the relating interface will be selected, otherwise the English one will be loaded.
Afterwards, you can select the option you need independently of the Operating System language, excluding the interface of the present Help: the CHM viewer is a Windows component, its interface is always displayed in the language of the current Windows installation.
The contents of the Help are displayed in English or Italian.
In some parts of the software, when the cursor hovers an item, a short description may appear on the status bar at the bottom.
Example: in "Settings", "my Cylinders", "Add new bottle", when the cursor enters over the field "Int.Vol.Liters", the yellow ToolTip appears in the status bar
Here you can activate or deactivate this feature
Main settings check
This window appears the first time you launch the application and allows you to set the main settings.
Reset Units to default
• Reset Disclaimer: shows the disclaimer at startup
• Reset EOS: Real Gas Tech Gas Blender
• Reset Decimal Places:
The software is extremely powerful and configurable in depth , offering a high capacity for personalization.
• Reset Temperature (Isotherm): 20 °C
• Reset Gas Prices
• Oxygen invoice price: 5.50 euros
• Helium invoice price: 16 euros
• Reset max Oxygen % in the Continuous Flow EANx/Trimix : 35 %
• Reset Final pressure: 200 bar - 225 bar
• Reset Units of measurement:
• Pressure: bar
• Temperature: ° Centigrade (Celsius)
• Volume: Liters
• Currency: Euros
• Depth: Meters
• Weight: grams
• Reset Language: Operating System language
• Reset minimum Oxygen partial pressure: 0.21 ATA
• Reset maximum Oxygen partial pressure: 1.40 ATA
• Reset END: 25 meters
- Gas Percentage: 1
- Pressure: 1
- Temperature: 1
- Cylinder volume: 2
- Oxygen partial pressure: 2
- END: 1
- Depth: 1
• Ideal Gas - the simplest equation of state which is roughly accurate for weakly polar gases at low pressures and moderate temperatures; it considers the gas behavior as “Perfect gas” according to the equation PV = nRT