My next installment will cover Zero Air Generators. There are several models Restek sells, which vary by output flow rates and purity. Each of these models will be discussed below. They will include Parker 75-83NA, HPZA-3500, HPZA-7000, HPZA-18000, HPZA-30000. The most noticeable difference between these models is capacity.
75-83NA
The Restek part number for this generator is 20684. This model is capable of 1000 cc/min. The preferred installation is for this unit to be wall mounted, although it can be installed onto a benchtop. The Parker Installation, Operation and Maintenance manual can be found here TI-7583H.pdf The 75-83NA model takes compressed air and purifies it into zero grade air using a combination of filters and a catalyst. The prefilter removes oil mist, particulates, and moisture from the incoming compressed air supply. The catalyst oxidizes any remaining hydrocarbons from the compressed air supply into carbon dioxide and water. A second, final filter removes additional particulates.
Maintenance requirements for these generators include an annual maintenance kit, Restek 21646 (Parker MK7583) and a catalyst tower, Restek 22005 (Parker 75394, which needs to be replaced every two years).
Included in maintenance kit 21646:
- Prefilter (Parker 050-05-BX)
- Final filter (Parker A01-0185)
A couple of specifications to keep in mind: for every generator model listed in this post, the minimum/maximum incoming (compressed) air temperature is 60 °F/100 °F and the minimum/maximum incoming (compressed) air pressure is 40 psi/125 psi.
HPZA-3500
The Restek part number is 29282. This model has a maximum flow rate of 3500 cc/min. This unit is larger/heavier than the 75-83NA model, so the preferred installation is bench top, but it can be mounted on the wall. The Parker Installation, Operation and Maintenance manual can be found here TI-HPZA-3500H.pdf
In this model, compressed air is forced through two prefilters, followed by a catalyst tower, and finally through a final filter. The annual maintenance kits, Restek 21647 (Parker MK7840) and 29286 (MKZAG-12M), include the following:
- First stage prefilter (Parker 100-12-DX)
- Second stage prefilter (Parker 100-12-BX)
- Final filter (Parker GS-050-05-95)
A catalyst tower, Restek 22004 (Parker 76810), is also available. Unlike the replacement schedule for the 75-83NA model, the catalyst tower should be replaced when the following occurs (according to page 7 of the manual):
The catalyst module in the Parker Balston Zero Air Generator should be changed when the “Check System” LED is illuminated or blinking to maintain the hydrocarbon removal specification for the unit.
HPZA-7000
The Restek part number for Parker model HPZA-7000 is 29283. As you may have guessed, the maximum flow rate is 7000 cc/min. The manual is the same as for HPZA-3500, TI-HPZA-3500H.pdf, and so are the maintenance kits (Restek 21647, Parker MK7840; and Restek 29286, Parker MKZAG-12M), but the catalyst tower is different (Restek 22006, Parker 76820). Preferred installation is on a bench top.
HPZA-18000
The Restek part number for this generator is 29284. The maximum flow rate is 18,000 cc/min. Once again, the maintenance kit is the same (Restek 21647, Parker MK7840) but the catalyst tower is different 22007 (Parker 76811).
HPZA-30000
The highest capacity zero air generator Restek sells is Parker’s HPZA-30000 model, Restek 29285. This unit has a maximum flow rate of 30,000 cc/min. As you may expect, the maintenance kits are the same (Restek 21647, Parker MK7840; and Restek 29286, Parker MKZAG-12M) but the catalyst tower is different 22008 (Parker 76821).
As you can see, generator selection is straightforward; simply select the zero-air generator that matches your flow needs. Then, instead of the drudgery of changing zero-grade air cylinders, use a zero-air gas generator instead. Thanks for reading.
