Airmetrics MiniVol User manual

MiniVol
Portable Air Sampler
Operation Manual
Airmetrics
2121 Franklin Boulevard, #9
Eugene, OR 97403
U.S.A.
PHONE: [phone]
FAX: [phone]
E-mail: [e-mail]
www.airmetrics.com
Notice:
Information in this manual is subject to change without notice and does not
represent a commitment on the part of Airmetrics, which reserves the right to make
changes in construction, design, specifications, and/or procedures that may not be
reflected in this manual.
Printing History
Manual Version 1.0 - October, 1992, applies to Sampler M odels 3.x
Manual Version 1.0a - November, 1992, applies to Sampler Models 3.x
Manual Version 1.1 - June, 1993, applies to Sampler Model 4.0
Manual Version 1.1a - January, 1994, applies to Sampler M odel 4.0
Manual Version 1.2 - December, 1994, applies to Sampler Model 4.0
Manual Version 1.2a - July, 1996, applies to Sampler Model 4.1
Manual Version 4.2 - May, 1997 applies to Sampler M odel 4.2
Manual Version 4.2a - February, 1998 applies to Sampler Model 4.2
Manual Version 4.2b - December, 2000 applies to Sampler Model 4.2
Manual Version 4.2c - June, 2001 applies to Sampler M odel 4.2

Table of Contents
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Table of Contents
1INTRODUCTION 1
Principles of Operation ...................................1
Particulate Matter Sampling Mode .........................2
Integrated Gas Sampling Mode ...........................3
2GETTING STARTED 5
Inspecting Components ...................................5
Charging Batteries ......................................5
Connecting Sampler Body and Battery Pack ......................6
Removing Pump and Timer Assembly .........................7
Turning the Sampler On/Off ................................8
Programming the Timer ..................................8
Setting the Real-Time Clock .............................9
Setting the On/Off Times ...............................9
Setting the Timer to “On,” “Auto,” and "Off" Modes ...........10
Checking for Leaks ....................................11
3CONTROLS AND ADJUSTMENTS 13
All Operating Modes ...................................13
Elapsed Time Totalizer ...............................13
Programmable Timer ................................13
Flowmeter .......................................13
Flow Rate Adjustment ................................13
12V Battery Power Connector ..........................14
Low Flow Threshold Indicator ..........................14
Low Flow Cutoff Indicator .............................15
Low Flow Zero & Cutoff Adjustments .....................15
Low Battery Indicator ................................16
Lo-Flow/Lo-Battery Reset Switch ........................ 16
ON/AUTO/OFF Button ...............................17
Integrated Gas Sampling Option ............................17
Solenoid Valve Output C onnectors ........................ 18
Active Solenoid Output Indicators ........................18
Manual Sequence Advance Button ........................18
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Pulse Interval Adjustment ............................. 18
Pulse Duration Adjustment ............................ 18
Power On/Off .................................... 19
Pulse Indicator .................................... 19
Overlap Jumper ................................... 19
4PARTICULATE MATTER SAMPLING 21
Consumables ........................................ 21
Siting Requirements ................................... 21
Attaching the Mounting C radle ............................ 21
Preparing the Sampler .................................. 22
Flow Rate ....................................... 24
Flowmeter Calibration ............................... 25
Preseparator/Filter Holder Assembly ........................ 25
Clean and Grease Impactor ............................ 25
Installing Filters ................................... 26
Preparing the Battery Pack ............................... 27
Battery Charging .................................. 27
Changing/Installing Battery Pack on Sampler ................ 28
Other Battery Checks ............................... 28
Setting the Desired Sampling Time .......................... 29
Particulate Matter Sampling Procedure ....................... 29
Particulate Matter Sample Retrieval ......................... 30
Exposed Filter .................................... 32
Error Conditions .................................. 33
Low Battery Indicator ON ......................... 33
Low Flow Indicator ON ........................... 33
Overriding Low Flow /Low Battery Indicators ............. 34
5INTEGRATED GAS SAMPLING 35
Consumables ........................................ 35
Siting Requirements ................................... 35
Attaching the Mounting C radle ............................ 35
Preparing the Sampler .................................. 36
Operation Modes - Standard Mode or Overlap Mode ........... 36
Adjusting Pulse Frequency and Duration ................... 39
Pulse Interval Adjustment .......................... 40
Pulse Duration Adjustment ......................... 40
Preparing the Sampler .................................. 41
Installing Tedlar® Bags and Attaching Canisters .............. 42

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Integrated Gas Sampling Procedure ..........................44
Gas Sample Retrieval ...................................45
6HARDWARE DESCRIPTION 47
Pneumatic System .....................................47
Pneumatic System Flow Schematic ....................... 47
Filter Holder Assembly ...............................47
Flowmeter .......................................47
Flow Control System ................................47
Miniature Brushless D.C. Double Acting Diaphragm Pump .......47
Electronics System .....................................49
Motherboard ......................................49
Power ..........................................49
Programmable Timer ................................49
Flow Controller C ircuit ...............................50
Elapsed Time Totalizer ...............................50
Interconnect Board ..................................50
Motherboard E lectronics S chema tic ....................... 50
Battery Pack Charger Electronics Schema tic .................50
Valve D river Board Electronics Schematic ..................50
7MAINTENANCE 51
Preseparator/Filter Holder Assembly ......................... 51
Impactor Cleaning ..................................51
Flow Control System ...................................52
Programmable Timer ...................................53
Battery Pack .........................................53
Cleaning/Inspecting Pump Valves and Diaphragms ................53
Cleaning/Inspecting Pump Head Valves ....................54
8TROUBLESHOOTING 55
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Appendices
ASAMPLER FLOW RATE CALIBRATION 59
BGRAVIMETRIC ANALYSIS PROCEDURE 67
CQUICK REFERENCE 79
DWARRANTY POLICY 83
EREPLACING DAMAGED/DEFECTIVE COMPONENTS 85
FPARTS LIST 87
GFORMS and SCHEMATICS 105
List of Figures
Figure 2.1. Attaching Battery Pack 7
Figure 2.2. Programmable Timer 8
Figure 3.1. Sampler Contro ls and Adjustments 14
Figure 4.1. Mounted Sampler 23
Figure 4.2. Tubing Configuration for PM Sampling Mode 24
Figure 4.3. PM10 Preseparator and F ilter Holder Assem bly 26
Figure 4.4. PM2.5 Preseparator and F ilter Holder Assem bly 27
Figure 5.1. Tubing Configuration for Integrated Gas Sampling Mode 36
Figure 5.2. Installing Tedlar® Bag 42
Figure 5.3. Attaching Bag Canisters and Tubing 43
Figure 6.1. Pneumatic System Flow Schematic 48
Figure 7.1. Regreasing PM2.5 Impactor 52
Figure A.1. Portable Sampler Calibration Output 61
Figure B.1. Relative Hum idity Effects on Quartz Filters 72
Figure F.1. Main Circuit Board Parts Identification. 88
Figure F.2. Valve Driver Board Parts Identification 90
Figure F.4. Preseparator and Filter Parts Identification 94
Figure F.5. Battery Pack Parts Identification 97
Figure F.6. Integrated Gas Sampling Bag Parts Identification 99
Figure F.7. Mounting Hardware Parts Identification 101

Section 1: Introduction
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1INTRODUCTION
The MiniVol Portable Air Sampler is an ambient air sampler for particulate matter
and non-reactive gases. The patented low flow technology used in the MiniVol was
developed jointly by the U. S. Environmental Protection Agency (EPA) and the
Lane Regional A ir Pollution A uthority in an effort to address the need for portable
air pollution sampling technology.
While not a reference method sampler, the M iniVol gives results that closely
approximate reference method air quality data. Both accurate and precise, the
battery operated, lightweight MiniVol is ideal for sampling at remote sites or areas
without power. In addition, the low cost of the sampler allows a network of
MiniVols to be deployed at a fraction of the cost for a similar reference station
network.
The MiniVol features a 7-day programmable timer, a constant flow control system,
an elapsed time totalizer, rechargeable battery packs, and all-weather PVC
construction. The MiniVol can be configured to sample for just particulate matter,
just gases, or both simultaneously.
Principles of Operation
The MiniVol Portable Air Sampler is basically a pump controlled by a
programmable timer which can be set to make up to six "runs" within 24 hours or
throughout a week. When used outdoors it may be hung from a bracket mounted on
a variety of structures—utility poles, trees, fence posts, etc.
The sampler is equipped to operate from either AC or DC power sources. In the
DC operational mode, the sampler operates from a battery pack, thus making the
sampling site independent of line power. In the AC mode the battery pack is
connected to line power and mated to the sampler unit. This configuration charges
the battery while using AC power. The M iniVol comes with two battery packs to
accomplish continuous field sampling. A charged battery pack is capable of
operating the sampler for up to 24 sampling hours on a single charge.
The sampler is equipped with two "fault circuits":
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!A low battery circu it automatically shuts the sampler down should the
rechargeable lead-acid battery fail to supply sufficient voltage (below 10.3
volts) to the pump. This feature p rotects the battery which could be damaged if
used continuously at low voltage. A "low-battery" indicator lights to alert the
operator of this condition.
!A low flow circuit monitors the flow rate. Should excessive accumulation of
particulate m atter or som e restriction in the tubing cause the air flow to fall
below a specified rate, the sampler shuts down and a "low flow" indicator
lights to alert the operator.
An Elapsed Time Totalizer linked in parallel with the pump records the total time
in hours of pump operation.
PARTICULATE MATTER SAMPLING MODE
In the particulate matter (PM) sampling mode, air is drawn through a particle size
separator and then through a filter medium. Particle size separation is achieved by
impaction. Critical to the collection of the correct particle size is the correct flow
rate through the impactor. For the MiniVol, the actual volumetric flow rate must
be 5 liters per minute (5 lpm) at ambient conditions. To assure a constant 5 lpm
flow rate through the size separator at differing air temperatures and atmo spheric
pressures, the sam pler must be adjusted for each sampling project.
NOTE: The terms SIZE SEPARATOR, PRESEPARATOR and IMPA CTOR are
used interchangeably in this m anual.
Impactors are available with a 10 micron cut-point (PM10) and a 2.5 micron cut-
point (PM2.5). Operating the sampler without an impactor allows for collection of
total suspended particulate matter (TSP).
The inlet tube downstream from the filter takes the air to the twin cylinder
diaphragm pump. From the pump, air is forced through a standard flowmeter
where it is exhausted to the atmosphere inside the sampler body.
The program mable timer will automatically turn the pump o ff at the end of a
sampling period. The sampler must then be serviced and set up for the next
sampling period. Servicing includes removing the sampler from its hanging
bracket, removing the filter holder with the exposed filter inside from the sampler,

Section 1: Introduction
Airmetrics 3
and attaching a new filter holder with a fresh filter. The battery pack is also
changed at this time.
The sampling technique used by the MiniVol is a modification of the PM10
reference method described in the U. S. Code of Federal R egulations (40 CFR part
50, Appendix J). Under this criteria, a PM10 sampler must have: 1) a sam ple air
inlet system to provide particle size discrimination, 2) a flow control device
capable of maintaining a flow rate within specified limits, 3) means to measure the
flow rate during the sampling period, and 4) a timing control device capable of
starting and stopping the sampler.
The Airmetrics MiniVol Portable Air Sam pler meets all of these specifications. It
is equipped with: 1 ) an inlet impactor capable of se parating particulate matter to
#10 µm, 2) a flow control device which will maintain a specified flow rate, 3) a
flowmeter to measure the flow rate during the sampling period, 4) an elapsed time
meter, and 5) a programmable timer that starts and stops the sampler unattended.
The MiniVol's flow rate is generally less than the flow rates used by reference
method devices. The lower rate results in a greater deviation in accuracy at low
concentrations of particulate matter where precision can be lost through the
handling and weighing of a minute p articulate sample. Howeve r, at high particulate
concentrations the sampler produces results that are precise and com parable to
reference method samplers.
While the MiniV ol's sampling method is no t a reference or equivalent method, it
has proven to be an excellent indicator of absolute ambient PM10 concentrations.
Although the method used by portable PM10 sampling does not wholly conform or
comply with the reference method, the data collected by the sampler still serve as a
useful supplement to data generated by PM10 reference methods.
INTEGRATED GAS SAMPLING MODE
In the integrated gas sampling mode, the sampler can accommodate one or two bag
modules. The bags may be filled one at a time or simultaneously within a
programmable period. There are two circuits which control the gas sampling:
1. A tuneable intervalometer, or pulse circuit, determines the rate at which a bag
is filled. The circuit sends an electronic pulse to open a solenoid on the valve
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4Airmetrics
driver board. The duration of each pulse can be adjusted from approxim ately
50 to 750 milliseconds. The pulses can also be adjusted for frequency, from
one pulse every 15 seconds to continuously on.
2. A bag sequencer determines which of the two bags is being filled during any
programmed inte rval.
While the bags that are supplied with the samplers are made of relatively non-
reactive Tedlar® (polyvinyl fluoride), other parts of the air path are made of PVC,
polyethylene, silicone rubber, and other substances that are more reactive.
Consequently, you should not use the MiniVol to collect gas samples that are to be
analyzed for reactive gases like ozone or sulfur dioxide.
In the gas sampling mode, the air that is used to fill the bags is diverted from the
normal air path just before the air is vented into the sampler case—at the end of the
air path. Because of this, you may simultaneously collect a PM sample (the filter
holder is situated at the beginning of the air path) while collecting a gas sample.

Section 2: Getting Started
Airmetrics 5
2GETTING STARTED
Inspecting Components
When purchased, a standard MiniVol comes packed in two plastic carrying cases,
one containing two battery packs and a transformer, the other containing the
sampler and two preseparator/filter holder assem blies. A m ounting cradle is
shipped outside of the carrying boxes. Each sampler includes:
!1 pump module
!2 preseparator/filter holder assemblies
!2 battery packs
!1 18-volt transformer
!2 plastic carrying cases
!1 mounting cradle
If you ordered the Integrated Gas Sampling option, you will also receive:
!1 valve driver board (pre-installed on back of main circuit board)
!4 collection canisters, each with a 6-liter Tedlar® bag
!1 24-inch bale bar with removable end caps
!1 special bale handle
Every order also includes an Operation Manual and a packet of spare parts.
On receipt, visually inspect the contents of the cases to account for all components.
Compare the equipment delivered with the enclosed packing slip. Notify Airmetrics
of any missing or damaged equipment (see Appendix D).
Charging Batteries
1. Connect the charging plug of the transformer to the charging jack on the first
battery pack.
2. Plug the transformer into a fused AC outlet.
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NOTE: A Switching AC Adaptor is sup plied with a new sampler. This
universal transformer/adaptor is rated for 100-240 VAC, 50-60 Hz, and
features a 3-pole plug. The user may need to purchase a standard computer
power cord with local plug configuration to connect the tran sformer to a wall
socket for battery recharge.
3. The green LED on the top of the battery will light indicating that the battery is
being charged. W hen this light goes out, the battery is charged but continues to
receive a “trickle” charge as long as it is plugged into the charging
transformer. A fully discharged battery requires at least 18 hours to be
completely recharged.
4. If the battery will be used frequently, leave it plugged into the charging
transformer until its next use. Leaving the battery plugged in allows it to
receive a trickle charge maintaining the battery in a fully charged state. DO
NOT, however, store the battery for extended periods of time while plugged
into the charging transformer.
!The charging LED (green) should light briefly even if the battery is already
fully charged. If the charging LED on the battery fails to light, either the LED
is faulty or the charger is defective (see "Troubleshooting" sec tion).
!The batteries supplied with the sampler are of the lead-acid type. Since these
batteries may vent hydrogen gas while charging, they must be charged in a
well-ventilated area so that the hydrogen gas does not build to an explosive
concentration.
Connecting Sampler Body and Battery Pack
1. Remove the packing foam from the bottom of the sampler body.
2. Lift the sampler over the battery pack and carefully insert the banana pins
extending from the sampler bottom into the sockets on the top of the battery
pack. The pins are unevenly spaced and can fit only one way—the pin closest
to a latch on the sampler body inserts into the odd colored receptacle on
the battery pack (see Figure 2.1).
3. Clamp the two latches.

Section 2: Getting Started
Airmetrics 7
Figure 2.1. Attaching Battery Pack
Removing Pump and Timer Assembly
The bale assembly bar secures the 6" diameter top cap to the sampler body. To
remove the pump and timer assembly from inside the sampler body:
1. Lift the pump and timer assembly out holding the 6" diameter top cap, taking
care not to pull the connecting wire loose or jar the pump hose fittings.
2. Since the short connecting wire does not allow the assembly to be removed
from the sampler body beyond a few inches, rest the assembly on the edge of
the sampler casing by using the triangular mount stand. Leave the battery
attached to the sampler to stabilize the unit, and hold the assembly by the top
cap. Do NOT grasp the circuit board.
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8Airmetrics
Figure 2.2. Programmable Timer
L
Turning the Sampler On/Off
The ON/AUTO/OFF button on the
Programmable Timer allows the
operator to manually turn the
sampler on or off (or to place it in
the "Auto" mode in which it is
controlled by programmed on/off
sequences). As the ON/AUTO/OFF
button is pressed, a bar at the lower
edge of the LCD display moves
horizontally over the words "On",
"Auto" and "Off" which are printed
on the timer case (see Figure 2.2).
With the sampler attached to a
charged battery pack, press the
ON/AUTO/OFF button until the bar
is above the "On" legend. The red
power indicator (to the right of the
ON/AUTO /OFF button) should
light and the pump motor should
start.
If the Timer display does not respond, check the single A A battery on the circuit
board. Removing the battery resets the timer and clears the display.
While the sampler is running, press the ON/A UTO/OFF b utton, until the bar is
over the O FF legend. The power indicator light will go off and the pump w ill
stop running.
Programming the Timer
The Programmable Timer can be set to run up to six on/off cycles within a 24 hour
period, as well as to run for separate time periods on separate days within a 7-day
period. To set the timer, first set the real-time clock to establish the correct time
frame in which the cycles are to run. Next, enter the on/off times at which the
programmed cycles are to begin and end. Finally, set the timer to "Auto" mode.

Section 2: Getting Started
Airmetrics 9
L
Refer to Figure 2.2 when performing the following procedures.
SETTING THE REAL-TIME CLOCK
1. DAY SET: Hold dow n the CLOCK button and press the WEE K button until
the correct day appears at the top of the display.
2. TIME SET (Hour): Hold down the CLOCK button and press the HOUR
button until the display indicates the correct hour. You may have to cycle
through the hours twice to obtain the proper AM or PM (on the left side of the
display). Seconds will automatically reset to zero.
3. TIME SET (Minutes): Hold dow n the CLOCK button and press the M IN
button until the display indicates the correct m inutes. Seconds w ill
automatically reset to zero.
SETTING THE ON/OFF TIMES
1. Press the PROG button once. 1ON will appear near the lower left corner of the
display indicating that the power-on time for the first cycle is ready to be
programmed.
2. Press the HOUR and MIN buttons to enter the power-on time for the first
cycle.
3. Press the WEEK button to select the desired day. The days appear along the
top of the display. Continuou sly pressing the WEEK button will sequentially
display "Mo Tu We Th Fr Sa Su", "Mo", "Tu", "We", "Th", "Fr", "Sa",
"Su", "M o Tu W e Th Fr", "Sa Su" and finally back to
"Mo Tu We Th Fr Sa Su". When more than one day is displayed, these days
will all have the same power-on time.
4. After you have entered the power-on time and date for the first cycle, press the
PROG button. 1OFF now appe ars on the display to indicate that the power-off
time for the first cycle is ready to be program med. Repeat steps 2 and 3 to
enter the desired power-off time.
The power-off tim e does not have to occur on the same day as th e on time. In this
way, sampling may start on one day and end on the next day.
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10 Airmetrics
L
5. Press the PROG button again. 2ON appears on the display to indicate that the
second power-on time is ready to be programmed. Repeat steps 2 to 4 to enter
the remaining power-on/power-off times (up to 6 on/off times).
6. Press the PROG button to step through the times you entered to make sure
they are correct.
Press the RST/RCL button to disable (ReSeT) or reactivate (ReCalL) any time
entries. When you disable a particular power-on/off entry, four dashes w ill
appear instead of the time. When you reactivate an entry, it will return to the
values that were set before you perform ed a reset.
Be sure to clear all unwanted time entries prior to sampling in the AUTO mode.
Both ON and OFF entries need to be disabled for the unwanted programs to be
inactive.
7. Press the CLOCK button to return to the real-time clock display.
8. Press the ON/AUTO/OFF button until the bar is positioned above the "OFF"
legend.
SETTING THE TIMER TO “ON,” “AUTO,” AND "OFF"MODES
The ON/AU TO/O FF button is used to manually turn the sampler on or off, or to
place it in the "Auto" mode. A bar on the lower edge of the LCD display moves
from "Off" to "Auto" to "On" as the button is pressed. In the "Auto" mode the
sampler is controlled by the programmed on/off sequences.
!To manually turn the sampler ON, press the ON/AUTO/OFF button until the
bar on the lower edge of the display is above the "ON" legend. The pum p will
start and the power indicator w ill light.
!To manually turn the sampler OFF, press the ON/AUTO/OFF button until the
bar is above the "OFF" legend.
!To set the timer to "A UTO" mode in which the sam pler will be automatically
controlled by programmed sequences, first turn the sampler OFF. Then press
the ON/AUTO/OFF button until the bar is above the "AUTO" legend.

Section 2: Getting Started
Airmetrics 11
Checking for Leaks
To check for leaks, remove the preseparator/filter holder assembly and cover the
air inlet at the top of the sam pler body with the palm of the hand while the pump is
running. The ball in the flowm eter should drop immediately to zero and remain
there without movement. If it does not, a leak exists somewhere in the hoses and
fittings between the inlet and the flowmeter. Leaks on the inlet side of the pump
are especially critical, since flow measurement will not accurately reflect the
amount of air passing through the filter. The sampler will be measuring air passing
through the filter, plus whatever air may be entering through the leak.
!Verify that all push-on hose fittings are secure.
!Check the screw fittings attached to the pump. T hese must be screwed in
securely. Unlike p ipe threads these fittings "seat" into their connecting socket.
Do NOT attempt to tighten these fittings with a wrench, since too much
pressure could break them. If any appear loose, tighten by hand to a "finger
snugness."
!Check the push-on hose fitting beneath the 6" white cap just below the quick
connect.
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Section 3: Controls and Adjustments
Airmetrics 13
3CONTROLS AND ADJUSTMENTS
All Operating Modes
The following controls (see Figure 3.1) are used to set the operation of the
MiniVol in both the particulate matter sampling mode and the gas sampling mode.
ELAPSED TIME TOTALIZER
The Elapsed Time Totalizer displays the total number of hours, with a resolution of
tenths of hours, that the pump has run. The totalizer accum ulates time only while
the pump is running. It cannot be reset to zero. The total hours should be recorded
at the beginning and end of each sampling period.
PROGRAMMABLE TIMER
The Programmable Timer controls the on/auto/off operation of the sampler. The
timer allows up to six sampling times to be preprogrammed over twenty-four hours
or throughout a w eek (see "Prog ramming the Timer").
FLOWMETER
The Flowmeter indicates the flow rate of air through the system in liters/minute.
The flow rate is adjusted using the "Flow Rate Adjustment".
The flowmeter rea dings must be taken from the center of the ball.
FLOW RATE ADJUSTMENT
The Flow Rate Adjustment potentiometer (knob) varies the sampler's flow rate as
indicated by the level of the ball (read from the center of the ball) in the flow meter.
Slowly turn the knob until the air flow reaches the desired level. The sampler's
Flow Control Circuit will attempt to maintain this flow rate by varying the speed of
the pump as particulate matter accumulates on the filter.
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14 Airmetrics
Figure 3.1. Sampler Controls and Adjustments
12V BATTERY POWER CONNECTOR
The 12V Battery Power Conn ector is a standard ph one plug-in jack which conducts
power from the battery to the sam pler.
LOW FLOW THRESHOLD INDICATOR
The Low Flow Threshold Indicator light is activated when the flow sensor
determines that the air flow rate has dropped som e increment below the flow rate