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Fax: 978-562-8986

"High Precision Air Pressure Regulation for plastic tubing extrusion"

MicroAir series of Ultra Low Pressure Air Regulators

and Controllers for Manufacturers of Extruded Tubing.

White Paper "Extrusion Process and the need for Air Pressure Control"

"All models are now CE Certified for shipment to Europe."

The MicroAir provides high precision control of tubing outside diameter by regulating air pressure to a set point during the manufacture and extrusion of medical, catheter and automotive tubing. MicroAirs are used to regulate and control pressure for precise air sizing of extruded plastic tubing. Pressure is maintained for widely varying flow rates such as when a cut is made or variations in your process, etc. The "force balance regulator" provides instantaneous response to changes in flow rate and maintains a set pressure with flow rates from near zero up to the rated maximum. Both our low-tension spring models and our high speed linear solid-state model offer some of the highest flow rates in the industry.

air pressure regulators

Maintaining tubing dimensions are critical during medical tubing/catheter extrusion. While tubing has gotten smaller and smaller over the last 30 years, our MicroAir units have been continually updated and improved upon for better stability, and precision at lower and lower air pressure.

Each MicroAir includes a magnehelic pressure meter accurate to 2% of full scale.
Meters available in inches of water, pounds per square inch (psi), mbar, kPa, etc.
A fluid filled chamber mounted below the pressure relief valve adds viscostatic damping to ensure stable, hysteresis free operation.
(Note: oil does not come in contact with the regulated air)
Repeatability is better than 1% of full scale. Full scale is the maximum air pressure output ordered.

Single channel MicroAir I, MicroAir II and MicroAir IV units are built in
stainless steel enclosures 12" x 10" x 6".

Multi-channel units for multi-lumen tubing are available in all models (see below).

A 3-year Factory Warranty is offered on all units. Our highly-reliable MicroAirs have a life-expectancy of 10-20 years.

All units are manufactured in the United States of America at our Hudson, Massachusetts facility
and can be shipped worldwide by UPS, DHL, or FEDEX. A padlockable door latch has been added to all units. ALL MicroAir units are built in house specifically for your order requirements and tested to assure quality and repeatability.

MicroAir Catalog Sheet

MA 2015 Specification Sheet

MicroAir I Ultra Low Pressure Air Regulator (MAI)

MicroAir I

Pressure Control: The set point may be adjusted manually on a MicroAir I. When connected to standard factory air supply, the MicroAir's regulator balances the output pressure against a low-tension spring and expels surplus air to the atmosphere making it a complete air support system. This "force balance regulator" provides nearly instantaneous response to changes in flow rate and maintains a set pressure with flow rates from near zero up to the rated maximum. Manual model controlled by a single 30 turn fine adjustment knob.

MAI knob

Air Input: The air inlet is connected to normal factory air which has been regulated down to approximately 50 psi.
Available in single, dual and 3-channel units for multilumen tubing.


MicroAir II Ultra Low Air Pressure Regulator and Controller (MAII)

MicroAir II/>
    <p><font color=Pressure Regulation and Control: The MicroAir II accepts Air Up and Air Down contact closure inputs from a Diameter Gauge, or other controllers with up/down contact closures or logic outputs. Pressure is regulated by balancing against a low tension spring and by venting the surplus air. Two front panel buttons for manual control and the externally controlled inputs for auto control adjust the pressure set point by means of a small motor which adjusts the spring tension. The buttons are dual-speed. Indicators show Up, Down, and limit conditions. Zero to full Scale in approximately 2 minutes.

Air Input: The air inlet is connected to normal factory air which has been regulated down to approximately 50 psi.

Power: 115/220 VAC power. 50/60 Hz

MicroAir II with digital


MicroAir II with Remote MicroAir II models

Remote control unit for MicroAir II. A small (8"x5"x2") box with standard 100 foot cable, with up/down control buttons and digital display. Remote connects to 4-20 ma output option in MicroAir II.

MicroAir IV

MicroAir IV Ultra Low Pressure Air Controller
with 0-10 volt input for controlling by PLC or other device
and for high speed switching when making bump/taper tubing.(MAIV)

Application: The MicroAir IV was originally designed for the manufacturers of bump tubing where the pressure must be switched quickly or varied in a controlled way. The MicroAir IV accepts a logic input to select one of two set points, and a zero to 10 VDC analog input to provide any pressure from near zero to full scale instantaneously. Can be connected to your PLC or any controller with the 0-10 volt input and if an added output option, can have closed loop control.

Operation: The MicroAir IV is connected to normal factory air within the range of 50 to 120 psi. It then regulates to the pressure set by a 0 to 10 volt input, or to one of the two manually set pressures by expelling surplus air. A precision voice-coil linear motor (no spring) with viscostatic damping ensures optimum speed and stability.

Operational Modes: In Dual-state mode a logic signal selects which of two pressure set points is active. The Hi and Lo set points are adjusted with front panel buttons. In Linear mode a zero to 10 volt input controls pressure and the adjustable set points are ignored. A manual pressure setting can be set by turning the left side potentiometer only.

Performance: The MicroAir IV responds to a step of 50% of full scale in less than 0.1 second (typically 20 msec) and maintains an accurate pressure at flow rates between zero and a maximum SCFH depending on the full scale range.

Power: 115/220VAC. 50/60 Hz

MA4 graph


MultiAir - Multiple Channel MicroAir Units

Dual MicroAir II

For Multilumen applications the MicroAir units are offered with up to four channels in a single stainless steel enclosure with one air inlet.

Air Input: The air inlet is connected to normal factory air which has been regulated down to the 55 - 65 psi range.

Models available:

4-Channel MicroAir IV with Digital/></p>

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Our MicroAir units are:

On Line Controls prides itself on being dedicated to applying our knowledge and resources to understand, support and meet our customer needs. Our products can be shipped by UPS or FEDEX throughout the United States, Mexico and Canada. Our international customers include companies in Ireland, Spain, France, Italy, Switzerland, Germany, Malta, Poland; China, Thailand and India, etc. We can ship worldwide with UPS, DHL, TNT or FEDEX.



DS Line

REPAIRS: All old MicroAir units with a serial number of 7000 or above are repairable. Any older MicroAir units with a serial number below 1999 (more than 20 years old) may be repairable but you will have to send the unit in for evaluation. We recommend purchasing a new unit for higher precision and stability than repairing a 20 year old unit.

On Line Controls, Inc.
9A Kane Industrial Drive
Hudson, MA 01749-2905 U.S.A.
Tel: 978-562-5353 Fax: 978-562-8986 Email: olc@onlinecontrols.com

Updated February 2017