Full NER Steps include:
- Make sure your pressure builder and gas use valve are securely closed
- Open the Vent valve and connect a fill source to the liquid connection on the liquid cylinder
- Fill the Vessel with liquid nitrogen to “full” level by weight and leave the vent open allowing the liquid to fully stabilize (ie- until venting stops)
- If the vessel vents continuously for several (3-4) hours after filling and shows no sign of slowing down then check to make sure your pressure building line is not leaking past the valve. If it is then your pressure building valve needs to be rebuilt or replaced. If the PB is fine then stop the test and save whatever product you can as you already know that your vessel needs to be sent in for service.
- Now, top off liquid level to replace initially vented product
- Log the weight of the filled vessel and leave the vent open
- After 24 hours, reweigh the vessel and log this (minus vessel tare weight) as “Net Starting Weight”
- Measure the weight of the vessel in two successive 24 hour periods
- Subtract the final weight from the starting weight to determine the total weight of product lost. In all cases subtract the tare weight of the vessel so that you are just logging the weight of the product. (net weight)
- Divide the net weight of product lost by the net starting weight to get the percentage of loss over two days.
- Divide that figure by two to get the daily NER.
- Make sure your pressure builder and gas use valve are securely closed
- Open the Vent valve and connect a fill source to the liquid connection on the liquid cylinder
- Fill the Vessel with liquid nitrogen to “full” level by weight and leave the vent open allowing the liquid to fully stabilize (ie- until venting stops)
- If the vessel vents continuously for several (3-4) hours after filling and shows no sign of slowing down then check to make sure your pressure building line is not leaking past the valve. If it is then your pressure building valve needs to be rebuilt or replaced. If the PB is fine then stop the test and save whatever product you can as you already know that your vessel needs to be sent in for service.
- Now, top off liquid level to replace initially vented product
- Log the weight of the filled vessel and leave the vent open
- After 24 hours, reweigh the vessel and log this (minus vessel tare weight) as “Net Starting Weight”
- Measure the weight of the vessel in two successive 24 hour periods
- Subtract the final weight from the starting weight to determine the total weight of product lost. In all cases subtract the tare weight of the vessel so that you are just logging the weight of the product. (net weight)
- Divide the net weight of product lost by the net starting weight to get the percentage of loss over two days.
- Divide that figure by two to get the daily NER.
Posts
