Most pressure chamber users will use Nitrogen (N2) “Welding Nitrogen” which is an inert gas and does not react with the plant sample. This has been the industry norm for some time. If you do not already have nitrogen, a “Nurse Tank” can normally be bought or rented from a welding supply store or gas supply store at minimal cost.
IMPORTANT – if you have a Portable Tank and not the internal tank of a Model 610 – click here to use different instructions.
Filling the Internal Tank of the Model 610 is easy but care must be taken while trans-filling high pressure nitrogen. First, you need to have 3 items in order to make a successful fill of the Internal Tank. You need:
- Model 610 Pressure Chamber Instrument (with internal tank)
- Nurse Tank (Large filling tank)
- 6 foot connector hose (filling hose)
Nurse Tank (left), Model 610 (right), Filling Hose (front/center)
First, connect the Filling Hose to the Nurse Tank (should be hand tight)
Next, connect the filling hose to the Model 610 Instrument (pull back on female coupler to make connection) pull gently to ensure you have a safe connection
Your system should now look like this
Ensure that the the following valves are shut before proceeding
Nurse Tank Valve, Bleeder Valve, Inlet Shut-off Valve, Internal Tank Valve
Now you are ready to start filling
Start by opening up the Nurse Tank Valve completely
This will allow pressure down to the Inlet Shut-Off Valve
Next, open the Inlet Shut-Off Valve – You will see the pressure rise on the “Tank Pressure” gauge
BARELY OPEN THE INTERNAL TANK VALVE
JUST CRACK IT OPEN
Allow the nitrogen to slowly fill the Internal Tank
You will hear the nitrogen as it fills the tank. You should take about 4-5 minutes to fill the tank. As the pressure equalizes, continue to open up the valve a little bit more. Continue this process until the pressure has equalized completely. If you open the valve up to quickly and let too much gas into the tank – the valve will become HEATED and will have problems or fail. This is due to the gas compressing into the empty tank.
When the pressure has equalized, seal the Internal Tank first, then seal the Nurse Tank. Lastly seal the Inlet Shut-Off Valve. The bleeder valve will allow you to let the pressure escape from the hose. Now you can disconnect your hose from the Model 610 Pressure Chamber and store the Filling Hose and Nurse Tank You are now ready to take measurements.