Filter Regulators (Piggybacks)
Filters
ARO-Flo Piggyback Filter Regulators
A filter regulator, which ARO calls a piggyback, combines a compressed air filter and a pressure regulator in a single compact body. As an air regulator and filter in one unit, it cleans the air and sets its pressure with fewer joints and less space than two separate components, which makes it the usual choice at the point of use on machines and where room is tight. This page carries 56 ARO-Flo piggybacks across four series, from 1/8" to 1" NPT: 48 with 5 micron particulate elements and 8 with 0.3 micron coalescing elements, with or without a gauge.
Piggyback or Separate Filter and Regulator?
A piggyback air regulator filter and a separate filter and regulator both deliver filtered, regulated air. The choice comes down to space, flow and flexibility.
| Piggyback filter regulator | Separate filter and regulator | |
|---|---|---|
Footprint |
One body, one set of connections. A panel nut is standard for mounting through a panel |
Two bodies joined in line |
Flow |
Lower than separate units of the same size, e.g. 172 SCFM for the 1/2" 2000 Series |
Higher: the 1/2" 2000 Series filter is rated at 197 SCFM and the regulator at 210 SCFM |
Flexibility |
Filter element, spring range, bowl and drain chosen together in one part number |
Each stage chosen, serviced and replaced on its own |
Typical use |
Point-of-use supply to machines, pumps and cylinders, and tight spaces |
Higher-flow branches and main lines |
Size by Flow
Choose the series by the air flow the equipment draws. Filter regulator air flow ratings below are at 100 psi inlet and 90 psi set pressure.
ARO-Flo 1000
1/8" and 1/4" ports
43 SCFM at 1/8", 47 SCFM at 1/4"
Single tools, small valves and actuators
ARO-Flo 1500
1/4" and 3/8" ports
72 SCFM at 1/4", 90 SCFM at 3/8"
Individual machines and branch lines
ARO-Flo 2000
3/8", 1/2" and 3/4" ports
132 SCFM at 3/8", 172 SCFM at 1/2", 173 SCFM at 3/4"
Groups of equipment
ARO-Flo 3000
3/4" and 1" ports
236 SCFM at 3/4", 250 SCFM at 1"
High-demand branches, metal bowls only
Choose the Element, Range, Bowl and Drain
- Filter element 5 micron particulate on 48 models. 0.3 micron coalescing on 8 models: P39223 and P39233 (1500 Series, 1/4" and 3/8"), P39343 and P39353 (2000 Series, 1/2" and 3/4").
- Pressure range 0-140 psi as standard, plus 0-60 psi (P39124-200, P39224-210, P39344-210) and 0-30 psi (P39124-400).
- Gauge Part numbers with a 6 right after the dash have a flush-mount gauge with settable pointers. The others have a 1/8" gauge port.
- Bowl Polycarbonate with guard (150 psi, 23°F to 125°F), metal, or metal with sight glass (250 psi, 23°F to 175°F). The 3000 Series is metal only.
- Drain Manual, or automatic for units that are hard to reach or see a lot of water.
Reading a piggyback part number
In P39344-614, the fourth digit is the series (1 = 1000 up to 4 = 3000), the fifth the port size (1 = 1/8" up to 6 = 1") and the sixth the element (4 = 5 micron, 3 = 0.3 micron). After the dash: the range and gauge (1 = 0-140 psi, 2 = 0-60 psi, 4 = 0-30 psi, 6 = 0-140 psi with gauge), the bowl (0 = polycarbonate, 1 = metal with sight glass, 2 = metal) and the drain (0 = manual, 4 = automatic). So P39344-614 is a 2000 Series 1/2" 5 micron unit with gauge, sight glass metal bowl and automatic drain.
Where Piggybacks Fit Best
- At each machine or workstation, where every unit needs its own clean, set pressure
- On equipment frames and in panels, using the panel nut supplied with every piggyback
- On the air supply to air operated diaphragm pumps, which need filtered air but no lubrication
- Ahead of flow control and needle valves, so speed settings stay consistent
- With a lubricator downstream where tools need oil. Pre-assembled, that is a 2-piece FRL combination
Installation basics
Install the piggyback as close as possible to the equipment, with the bowl pointing down and the air flowing in the direction of the arrow. Before the first start-up, back the knob off fully so the equipment is not over-pressurized, then raise the pressure gradually.
Frequently Asked Questions
What is a piggyback filter regulator?
It is a compressed air filter and a pressure regulator built into one body, which ARO calls a piggyback. Air is filtered first, then reduced to the set pressure, so a single unit gives the equipment downstream clean air at a steady pressure. ARO-Flo piggybacks come with a 5 micron particulate element or a 0.3 micron coalescing element, from 1/8" to 1" NPT.
Can a filter regulator remove oil from compressed air?
The 0.3 micron coalescing piggybacks on this page capture oil aerosols as well as fine particles. They are available in 1/4" and 3/8" in the 1500 Series and 1/2" and 3/4" in the 2000 Series. As with any coalescing filter, ARO recommends a 5 micron general-purpose filter upstream to protect the coalescing element.
How do I set the pressure on a piggyback filter regulator?
Before turning on the air, turn the knob counterclockwise until the control spring is released. Then pull the knob up, turn it clockwise to raise the pressure to the setting you need, and push it down to lock. Models numbered -6xx after the dash have a flush-mount gauge whose pointers can be set to mark the working range.
Which piggyback should supply an air operated diaphragm pump?
ARO's 1/2" diaphragm pumps need air filtered to remove particles larger than 50 microns and need no lubrication, so a 5 micron piggyback covers both filtering and pressure setting in one unit. Size it from the pump's air consumption at your operating pressure, shown on the pump's performance curve. The pump inlet is 1/4", and the 66073-1 air line connection kit includes a filter regulator with hose and fittings.
Should I choose a manual or an automatic drain?
A manual drain has to be opened often enough to keep collected liquid below the baffle, or water is carried downstream. An automatic drain empties itself, which suits humid air, high water loads or units that are hard to reach. On this page, part numbers ending in 4 have an automatic drain and those ending in 0 a manual drain.
Two Jobs, One Compact Unit
For most point-of-use installations, a piggyback is the simplest way to get clean air at the right pressure: one part number, one set of connections and one place to check the gauge and drain.
Order the piggybacks above. For higher flows or separate servicing, pair an individual compressed air filter with an ARO pressure regulator from the air pressure regulators range. For pump installations, the 66073-1 air line connection kit on the pump parts and kits page includes a filter regulator. Application selections are on the industry pages for car wash, cosmetic & pharmaceutical and general manufacturing.
Need help choosing a filter regulator?
Talk to ARO about flow, filtration level or pressure range. Monday to Friday, 08:00 am to 5:00 pm CST.