THORLABS PACU User manual

PACU
Pure Air Circulator Unit
User Guide

Pure Air Circulator Unit
Table of Contents
Chapter 1Warning Symbol Definitions..............................................................................................1
Chapter 2Safety....................................................................................................................................2
Chapter 3Description...........................................................................................................................3
3.1.Introduction .....................................................................................................................3
3.2.Setup Description............................................................................................................ 3
3.3.Features ...........................................................................................................................3
3.4.Replacement Parts ..........................................................................................................3
Chapter 4Setup.....................................................................................................................................4
4.1.Unpacking PACU.............................................................................................................4
4.2.Installing the Supply and Return Lines and Operation ...............................................4
Chapter 5Operation..............................................................................................................................5
Chapter 6Maintenance.........................................................................................................................6
6.1.General Care Information ...............................................................................................6
6.2.Filter Replacements ........................................................................................................6
6.2.1.Step One: Top Panel Removal .............................................................................................6
6.2.2.Step Two: Removal of Filters................................................................................................7
Chapter 7Specifications......................................................................................................................8
Chapter 8Mechanical Drawing............................................................................................................9
Chapter 9Appendix..............................................................................................................................10
9.1.Declaration of Conformance ........................................................................................10
Chapter 10Regulatory...........................................................................................................................11
Chapter 11Thorlabs Worldwide Contacts..........................................................................................12

Pure Air Circulator Unit Chapter 1: Warning Symbol Definitions
Rev F, October 4, 2017 Page 1
Chapter 1 Warning Symbol Definitions
Below is a list of warning symbols you may encounter in this manual or on your device.
Symbol Description
Direct Current
Alternating Current
Both Direct and Alternating Current
Earth Ground Terminal
Protective Conductor Terminal
Frame or Chassis Terminal
Equipotentiality
On (Supply)
Off (Supply)
In Position of a Bi-Stable Push Control
Out Position of a Bi-Stable Push Control
Caution: Risk of Electric Shock
Caution: Hot Surface
Caution: Risk of Danger
Warning: Laser Radiation
Caution: Spinning Blades May Cause Harm

Pure Air Circulator Unit Chapter 2: Safety
Page 2 TTN004825-D02
Chapter 2 Safety
All statements regarding safety of operation and technical data in this instruction manual will only apply when the
unit is operated correctly.
CAUTION
Please read the instruction manual carefully before operating the PACU unit. All statements regarding
safety and technical specifications will only apply when the unit is operated correctly. This equipment
is intended for laboratory use only and is not certified for medical applications, including but not
limited to life support situations.
CAUTION
Latex gloves should be worn to prevent oil from fingers from reaching all connections and fitting
surfaces.
SHOCK WARNING
Check the supply voltage of the system before plugging in the unit. Make sure the included power
cord is connected to a properly grounded outlet (90 – 240 VAC; 50 – 60 Hz).
SHOCK WARNING
Before removing any of the panels to gain access to the inside of PACU, disconnect AC power. Make
sure the power cable is disconnected from the unit.

Pure Air Circulator Unit Chapter 3: Description
Rev F, October 4, 2017 Page 3
Chapter 3 Description
3.1. Introduction
The Pure Air Circulator Unit (PACU) is a stand-alone, closed-loop filtration system. It consists of several filters that
remove moisture and particulates. The unit is designed to operate in a closed-loop fashion. The exhaust or clean
air enters a cavity that is sealed from the external environment and exits that cavity back into the PACU. The PACU
is ideally suited for the continuous filtering and circulation of extremely clean, dry air (or nitrogen) in an optical cavity.
If the PACU is to be used in an open-loop system, the moisture trap should be monitored often, since the filter is
removing moisture from the surrounding environment.
A pump and three filters produce a continuous supply of extremely clean, dry air. An adjustable speed, micro-
diaphragm, in-line pump pumps the intake air into a conglomerate of filters.
Filter 1 is filled with an indicating desiccant for the removal of moisture, impurities, and particulates from the
circulated air. Filter 2 is also an indicating type molecular sieve to absorb volatile organic compounds (VOC). Purified
air then enters the final Filter 3 to remove any particulate sized greater than 15 um. This filter traps fine particles in
a dense matrix of a sintered element. This sintered metal filter’s elements are manufactured from stainless steel
powders via a powder metallurgy process.
In typical closed-loop operation, clean air is filtered into a closed cavity and then pulled back into the circulator to
be processed again to remove any additional moisture or particulates. It may be used in open-loop operation, the
indicating desiccant should be monitored and replaced if saturation has occurred.
3.2. Setup Description
The Thorlabs PACU Pure Air Circulator Unit is a self-contained unit that may operate as a tabletop unit or may be
rack mounted in a standard 19-inch rack cabinet. Access to the intake and supply line must be available. If the unit
is to be used in on a tabletop, then the rack ears and handles may be removed.
We recommend that the supply line tubing be a good-quality, low outgassing type, such as
fluoropolymer. This kind of semi-flexible tube maintains high integrity with less cross- contamination. We
use 3/16" ID x 1/4" OD x 3/32" wall, 266 PSI Chemfluor 367 Tubing throughout the unit.
Because the unit is self-contained, it is only necessary to connect the 1/4” tubing to the device that needs
to be purged with clean air.
The user should consider where the pure air will enter the unit and where the exhaust air will be drawn out
of the unit. Best results are achieved if the intake and exhaust are in the same plane, but this is not
absolutely necessary.
If the unit is in open-loop mode, or the volume to be purged is exposed to external air (moisture), then
periodic checks on the indicating desiccant are necessary.
The system uses a switchable power supply capable of 110 – 230 VAC, 50 – 60 Hz (90 – 264 VAC,47 –
440 Hz max rating).For support or more info, please contact [email protected].
3.3. Features
Closed-Loop Air or Nitrogen Filtration System
Adjustable Air Flow by Pump Speed
Sight-Gauged Air Flow Meter
1/4"Quick-Connect Hose Connections
3.4. Replacement Parts
Filter 1 – Desiccant Filter (PACU-FTR1)
Filter 2 and 3 (sold together) – In-Line 15 µm filter and Molecular Sieve (Part Number PACU-FTR3)
Tubing - 3/16" ID x 1/4" OD x 3/32" wall, 266 PSI, Chemfluor® 367 Tubing

Pure Air Circulator Unit Chapter 4: Setup
Page 4 TTN004825-D02
Chapter 4 Setup
The PACU pure air circulator unit is self-contained. 1/4” supply and return hoses are not included.
4.1. Unpacking PACU
1. Remove the unit, including the AC power cord, from its shipping container.
a. If the unit is to be used in a 19” rack mount chassis, use four 10-32 rack screws.
b. If the unit is to be used on a tabletop, and the rack ears and handles may be removed from the
unit.
2. The unit is configured to operate at 110 – 230 VAC, 50 – 60 Hz. Simply connect a power cord
appropriate for your geographic region. The unit includes a U.S. power cord. If you need a different plug,
please contact [e-mail].
4.2. Installing the Supply and Return Lines and Operation
SHOCK WARNING
Check the supply voltage of the system before plugging in the unit. Make sure the included power
cord is connected to a properly grounded outlet (90 – 240 VAC; 50 – 60 Hz).
The unit is designed for 1/4" tubing. We recommend type 3/16" ID x 1/4" OD x 3/32" wall, 266 PSI
Chemfluor® 367 Tubing. Chemfluor® 367, a unique fluoropolymer, maintains fluid integrity and in many
ways outperforms tubing made from standard, and even high-purity, PFA resin.
The surface is up to six times smoother than tubing made of standard and high-purity resin. This results in
less cross-contamination, greater productivity yields, and easier-to-clean systems.
This tubing can be used in virtually any application where maintaining high purity is critical, such as the
semiconductor, pharmaceutical, laboratory, environmental, or food processing industries. The operating
temperature ranges from -320 °F to 450 °F.
The unit operates most efficiently when providing clean air to a sealed enclosure with an air intake and an
air exhaust. This maintains the integrity of the desiccant for longevity. The desiccant is moisture-indicating
and is situated in a transparent filter container for inspection.
Once the supply lines have been installed, the unit may be turned on. A control knob regulates the
diaphragm pump speed. By increasing the speed, the amount of air flow will be increased. A flow meter
gauge measures air flow rates from 0 to 5 L/min. Clean air is supplied almost immediately after power on.
For optimal particle and moisture removal, the PACU should operate at a flow rate of 3 L/min.
A digital clock on the front panel keeps track of how long the unit has been powered up.

Pure Air Circulator Unit Chapter 5: Operation
Rev F, October 4, 2017 Page 5
Chapter 5 Operation
CAUTION
Please read the instruction manual carefully before operating the PACU unit. All statements regarding
safety and technical specifications will only apply when the unit is operated correctly. This equipment
is intended for laboratory use only and is not certified for medical applications, including but not
limited to life support situations.
The flow rate of the Viton membrane pump is continuously adjustable by a knob on the front panel and is measured
by an in-line flow meter immediately before the output. A series of vent holes is provided on top of the housing,
which makes it possible for the user to see if satuaration has occured in the desiccant without dismantling the unit.
Pink desiccant indicates that the desiccant is saturated and should be replaced. An elapsed time counter on the
front indicates how long the unit has been in service. For instructions on how to replace the desiccant filter, please
see section 6.2. During standard operation it is recommended that the air flow meter is checked in regular intervals.
! !

Pure Air Circulator Unit Chapter 6: Maintenance
Page 6 TTN004825-D02
Chapter 6 Maintenance
6.1. General Care Information
The desiccant filter that removes the moisture requires the most attention. The filter contains blue, indicating
desiccant. When indicating desiccant turns pink, the desiccant needs to be changed. Filter 1 and 2 may be inspected
through the vent holes in the top panel of the PACU unit.
Both Filters 1 and 2 are indicating when saturated and can easily be inspected for changing by their indicating color
change to pink. Filter 2 and Filter 3 should be changed together. The time period between filter changes depends
upon the chamber that is being filtered. When the unit is new, the flow meter typically peaks as the maximum pump
speed is approached. Should the filters be saturated, a reduced amount of air flow will show on the flow meter. We
have run the unit for hundreds of hours with no degradation of flow or increase in particle count. If it is deemed
necessary to change the particulate filters, they should be changed simultaneously.
6.2. Filter Replacements
Thorlabs uses indicating desiccant in the Pure Air Circulator Unit Filter 1, which changes color from blue to pink
when the desiccant is saturated with water. Filter 2 also uses a blue indicating material that will change its color to
pink when saturated. If either filter shows signs of saturation please replace them. The vent holes located on the
top panel of the PACU system offer a convenient way to check for saturation without having to disassemble the
unit. When used in a closed-loop system, the particulate filters used in the PACU should greatly outlast the
desiccant. Replace the particulate filter when you notice a decrease in flow rate at a given pump speed. The
instructions below describe the necessary steps to replace any of the three filters.
Thorlabs supplies replacement filters online at www.Thorlabs.com.
Required Tools:
Phillips Head Screwdriver
Flat Head Screwdriver
9/16” Wrench (Not Socketed) or Adjustable Wrench
Teflon Tape
6.2.1. Step One: Top Panel Removal
SHOCK WARNING
Before removing any of the panels to gain access to the inside of PACU disconnect AC power.
Make sure the power cable is disconnected from the unit.
To remove the top panel of the PACU system, use a Phillips head screwdriver to remove the four screws located
in the four corners of the panel (as shown in Figure 1).
Figure 1 Screw Locations
Figure 2 Removing Panel
After all four screws have been removed; the top panel can be removed by sliding the top panel towards the back
of the system which will free the opposite side to be gently lifted. If you find it difficult to slide the top panel

Pure Air Circulator Unit Chapter 6: Maintenance
Rev F, October 4, 2017 Page 7
back, you may need to slightly loosen the two screws on the tops of the side panels. Once lifted the
top panel can be pulled out (as shown in Figure 2).
6.2.2. Step Two: Removal of Filters
CAUTION
Latex gloves should be worn to prevent oil from fingers from reaching all connections and fitting
surfaces.
Once the top panel has been removed, you will have direct access to all three filters within the PACU system.
Before any filters can be removed, you must disconnect all hoses from filters 1 and 2 by loosening the hose clamp
connections. Do not remove the brass couplers. Loosening the clamp allows disconnection from the barbed filter
entrance and exit. Once both filters are disconnected they may be removed from the holding clamps. To remove
Filter 3, a flat head screwdriver and a 9/16” wrench or adjustable wrench is needed. The filter clamp holds Filter 3
in place and a Swagelok connection secures the tubing. Once all connections have been disconnected you may
remove that filter and replace it. Replacement filters can be purchased online at www.Thorlabs.com.
Figure 3 The red arrows indication locations where the indicating dessicant filter is connected to
the PACU System via hose clamps. Loosen the hose clamps and slide the tubing from the plastic
barb of the filter housing. Do not remove the brass couplers.
Figure 4 The red arrows indicate locations where the indicating particulate filter is connected to the
PACU System via hose clamps. Loosen the hose clamps and slide the tubing from the plastic barb
of the filter housing. Do not remove the brass couplers.
!
!

Pure Air Circulator Unit Chapter 7: Specifications
Page 8 TTN004825-D02
Chapter 7 Specifications
1The maximum value of 4.5 L/min occurs when the intake and exhaust are short circuited, i.e. directly connected.
2Moisture Trap Capacity: 50 g
Performance Specifications
Flow Rate10.6 to 4.5 L/min
Flow Meter Range 0.6 to 5 L/min
Filters
Moisture Trap2
(Desiccant) 1.25 lbs (0.6 kg) Desiccant
Particulate Filters 15 µm, Sintered Pore Element Filter
13X Molecular Sieve, 1.1 lbs (0.5 kg)
Air Pump Micro-Diaphragm Pump with 4.5 L/min Max Delivery
Internal Tubing Chemfluor®367 Fluoropolymer Tubing, 3/16" ID x 1/4"
OD x 3/32" Wall, 266 PSI
External Tube Fittings Type 316 Stainless Steel, Chemical-Resistant PVDF
Swagelok®Tube Fittings for 1/4" OD Tubing
Power Compatibility 110 - 230 VAC, 50 - 60 Hz Operation, Location
Specific Power Cord Included
Dimensions (L x W x H) 19.0" x 13.0" x 7.0" (483 mm x 330 mm x 178 mm)
Weight 6.8 kg

Pure Air Circulator Unit Chapter 8: Mechanical Drawing
Rev F, October 4, 2017 Page 9
Chapter 8 Mechanical Drawing

Pure Air Circulator Unit Chapter 9: Appendix
Page 10 TTN004825-D02
Chapter 9 Appendix
9.1. Declaration of Conformance

Pure Air Circulator Unit Chapter 10: Regulatory
Rev F, October 4, 2017 Page 11
Chapter 10 Regulatory
As required by the WEEE (Waste Electrical and Electronic Equipment Directive) of the European Community and
the corresponding national laws, Thorlabs offers all end users in the EC the possibility to return “end of life” units
without incurring disposal charges.
This offer is valid for Thorlabs electrical and electronic equipment:
Sold after August 13, 2005
Marked correspondingly with the crossed out “wheelie bin” logo (see right)
Sold to a company or institute within the EC
Currently owned by a company or institute within the EC
Still complete, not disassembled and not contaminated
As the WEEE directive applies to self-contained operational electrical and electronic products, this end of life take
back service does not refer to other Thorlabs products, such as:
Pure OEM products, that means assemblies to be built into a unit by the user (e. g. OEM laser driver cards)
Components
Mechanics and optics
Left over parts of units disassembled by the user (PCB’s, housings etc.).
If you wish to return a Thorlabs unit for waste recovery, please contact Thorlabs or your nearest dealer for further
information.
Waste Treatment is Your Own Responsibility
If you do not return an “end of life” unit to Thorlabs, you must hand it to a company specialized in waste recovery.
Do not dispose of the unit in a litter bin or at a public waste disposal site.
Ecological Background
It is well known that WEEE pollutes the environment by releasing toxic products during decomposition. The aim of
the European RoHS directive is to reduce the content of toxic substances in electronic products in the future.
The intent of the WEEE directive is to enforce the recycling of WEEE. A controlled recycling of end of life products
will thereby avoid negative impacts on the environment.
Wheelie Bin Logo

Chapter 1Thorlabs Worldwide Contacts
USA, Canada, and South America
Thorlabs, Inc.
56 Sparta Avenue
Newton, NJ 07860
USA
Tel: [phone]
Fax: [phone]
www.thorlabs.com
www.thorlabs.us (West Coast)
Email: [e-mail]
Support: [e-mail]
UK and Ireland
Thorlabs Ltd.
1 Saint Thomas Place
Ely CB7 4EX
Great Britain
Tel: [phone]
Fax: [phone]
www.thorlabs.com
Email: [e-mail]
Support: [e-mail]
Europe
Thorlabs GmbH
Hans-Böckler-Str. 6
85221 Dachau / Munich
Germany
Tel: [phone]
Fax: [phone]
www.thorlabs.de
Email: [email protected]om
Scandinavia
Thorlabs Sweden AB
Bergfotsgatan 7
431 35 Mölndal
Sweden
Tel: [phone]
Fax: [phone]
www.thorlabs.com
Email: [e-mail]
France
Thorlabs SAS
109, rue des Côtes
78600 Maisons-Laffitte
France
Tel: [phone]
Fax: [phone]
www.thorlabs.com
Email: [e-mail]
Brazil
Thorlabs Vendas de Fotônicos Ltda.
Rua Riachuelo, 171
São Carlos, SP 13560-110
Brazil
Tel: [phone]
Fax: [phone]
www.thorlabs.com
Email: [email protected]
Japan
Thorlabs Japan, Inc.
3-6-3 Kitamachi,
Nerima-ku, Tokyo 179-0081
Japan
Tel: [phone]
Fax: [phone]
www.thorlabs.co.jp
Email: [e-mail]
China
Thorlabs China
Room A101, No. 100, Lane 2891,
South Qilianshan Road
Putuo District
Shanghai 200331
China
Tel: [phone]
Fax: [phone]
www.thorlabschina.cn
Email: [email protected]
Pure Air Circulator Unit Chapter 11: Thorlabs Worldwide Contacts
Page 12 TTN004825-D02

www.thorlabs.com