Q

Are hydrogen generators difficult to maintain?

A

No, maintenance is easy and cost-effective. Simply fill the deionized water reservoir weekly/biweekly, or use the auto fill feature.

Q

Is it safe to use hydrogen from a hydrogen generator as a carrier gas?

A

Yes, in fact hydrogen generators offer several safety features that free-standing high-pressure gas cylinders do not.

1. Lower pressure is safer.
   The pressure output from a hydrogen generator is 60-100psi (414-689kPa), far lower than the high head pressure of a gas cylinder. By switching to a hydrogen generator you can remove dangerous high-pressure cylinders from your lab.
2. Controlled flow maintains safe hydrogen levels.
   The maximum flow capacity of hydrogen generators is only 300cc/min., well below the 2,000cc/min. of flow needed to reach the lower explosive limit (LEL) for hydrogen in air. This ensures the level in the GC oven is safe and does not create an explosive environment.
3. Built-in leak sensors and automatic shut down feature.
   All hydrogen generators offered by Restek are equipped with built-in sensing circuits that will automatically shut down the generator in the rare case that a leak is detected.
4. On-demand production means smaller storage quantities.
   A hydrogen generator typically only stores 50-100mL of gas at any one time and it is used immediately as it is generated. This is much safer than a free-standing gas cylinder which stores up to 9,000 liters at a time and can explode or become a dangerous projectile if dropped or released.

Q

How do I size a hydrogen generator for use as a carrier gas?

A

Follow these simple steps to determine which hydrogen generator is best for you. Always consult the hydrogen generator manufacturer for complete equipment specifications and recommendations for your particular situation.

1. Count the total number of columns you are using with splitless injection. Add up the on-column flow rate (cc/min.) for each column.
2. Count the total number of columns you are using with split injection. Add up the on-column flow rate for all columns (cc/min.), and then add the flow rate (cc/min.) coming off of each split vent port. Split vent port flows will account for most of the flow need.
3. Add up the flow rates calculated in steps 1 and 2; this is your total derived cc/min. flow rate.
4. Double the total derived cc/min. flow rate from step 3 (to account for changes in linear velocity) and match this value to the output flow capacity of the right hydrogen generator.