The preferred gas for pressure chamber use is welding grade nitrogen (N2) which is an inert gas and does not react with the plant sample. This has been the standard since the early 1960s. If you do not already have nitrogen, a large “Supply Tank” can normally be bought or rented from a welding or gas supply store at minimal cost.
IMPORTANT – if you do not have a Model 615 but instead have a Model 610 click here for different instructions. For a Portable Tank click here for instructions.
Filling the Internal Tank of the Model 615 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 Portable Tank. You need:
- 1. Model 615 Pressure Chamber Instrument
- Supply Tank (Large filling tank)
- 6 Foot Filling Hose
Supply Tank (left), Filling Hose (bottom left) Model 615 (right)
First, connect the 6-Foot Filling Hose to the Supply Tank (Hand tight)
Next, disconnect the instrument tank hose connection. (pull back on female coupler)
Connect the end of the Filling Hose to the Portable Tank hose. (Give the two hoses a gentle tug to ensure proper fitting)
Your system should now look like this
Ensure that the the following valves are shut before proceeding
Supply Tank Valve, Purge Valve, Portable Tank Valve
Now you are ready to start filling
Start by opening up the Supply Tank Valve completely.
This will allow pressure down to the Portable Tank It will also allow you to preview how much pressure is in the Supply Tank
BARELY OPEN THE INTERNAL TANK VALVE
JUST CRACK IT OPEN
Allow the nitrogen to slowly fill the Portable Tank
You will hear the nitrogen as it fills the tank. You should take about 1-2 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 too quickly and let too much gas into the tank – the valve will become HEATED and may have problems or fail. This is due to the gas compressing into the empty tank.
When the pressure has equalized, seal the Portable Tank first, then seal the Nurse Tank. The purge valve will allow you to let the pressure escape from the hose.
Now you can disconnect your filling hose and reconnect the 6 inch tank hose to hose connection port. Ensure that you have a good connection. You are now ready to take measurements.