horiba CFO-ONE User manual

CFO-ONE (Dual Critical Flow Orifice)
USER MANUAL
Release
GBUM220609V2
09/06/2022

©2018 HORIBA UK Ltd
Preface
This manual describes the operation of the CFO-ONE.
Be sure to read this manual before using the product to ensure proper and safe operation of the
instrument. Also safely store the manual so it is readily available whenever necessary.
Product specifications and appearance, as well as the contents of this manual are subject to
change without notice.
Warranty and Responsibility
HORIBA warrants that the Product shall be free from defects in material and workmanship and
agrees to repair or replace free of charge, at HORIBA’s option, any malfunctioned or damaged
Product attributable to HORIBA’s responsibility for a period of one (1) year from the delivery
unless otherwise agreed with a written agreement. In any one of the following cases, none of the
warranties set forth herein shall be extended;
•Any malfunction or damage attributable to improper operation
•Any malfunction attributable to repair or modification by any person not authorized by
HORIBA
•Any malfunction or damage attributable to the use in an environment not specified in this
manual
•Any malfunction or damage attributable to violation of the instructions in this manual or
operations in the manner not specified in this manual
•Any malfunction or damage attributable to any cause or causes beyond the reasonable
control of HORIBA such as natural disasters
•Any deterioration in appearance attributable to corrosion, rust, and so on
•Replacement of consumables
HORIBA SHALL NOT BE LIABLE FOR ANY DAMAGES RESULTING FROM ANY
MALFUNCTIONS OF THE PRODUCT, ANY ERASURE OF DATA, OR ANY OTHER USES OF
THE PRODUCT.
Trademarks
Generally, company names and brand names are either registered trademarks or trademarks of
the respective companies.

©2018 HORIBA UK Ltd
Regulations
Declaration of Conformity
HORIBA UK Ltd declares under our sole responsibility that this product is in conformity with the
protection requirements of the following Directives and Standards:
Directives: EMC Directive 2014/30/EU
Low Voltage Directive 2014/35/EU
RoHS 2011/65/EU
Standards: BS EN 61326-1:2006 Electrical equipment for measurement,
control and laboratory use. Class A
BS EN 61010-1:2001 Safety requirements for electrical
equipment for measurement, control and laboratory use Part 1:
General requirements
•Class ‘A’ - This equipment should not be used in the Residential, Commercial and Light
Industrial environment. Any apparatus used within a 30 metre radius may suffer from
interference.
•Information on Disposal of Electrical and Electronic Equipment
and Disposal of Batteries and Accumulators
The crossed out wheeled bin symbol with underbar shown on the product or accompanying
documents indicates the product requires appropriate treatment, collection and recycle for waste
electrical and electronic equipment (WEEE) under the Directive 2012/19/EU, and/or waste
batteries and accumulators under the Directive 2013/56/EU in the European Union.
The symbol might be put with one of the chemical symbols below. In this case, it satisfies the
requirements of the Directive 2013/56/EU for the object chemical.
This product should not be disposed of as unsorted household waste.
Your correct disposal of WEEE, waste batteries and accumulators will contribute to reducing
wasteful consumption of natural resources, and protecting human health and the environment
from potential negative effects caused by hazardous substance in products.
Contact your supplier for information on applicable disposal methods.

©2018 HORIBA UK Ltd
For Your Safety
Hazard Classification and Warning Symbols
Warning messages are described in the following manner. Read the messages and follow the
instructions carefully.
•Hazard classification
DANGER
WARNING
CAUTION
•Warning symbols
Description of what should be done, or what should be followed
Description of what should never be done, or what is prohibited
This indicates and imminently hazardous situation which, if
not avoided, will result in death or serious injury. This signal
word is to be limited to the most extreme situations.
This indicates a potentially hazardous situation which, if not
avoided, could result in death or serious injury.
This indicates a potentially hazardous situation which, if not
avoided, may result in minor or moderate injury. It may also
be used to alert against unsafe practices.

©2018 HORIBA UK Ltd
Safety Precautions
This section provides precautions to enable you to use the product safely and correctly and to
prevent injury and damage. The terms of DANGER, WARNING and CAUTION indicate the
degree of imminence and hazardous situations. Read the precautions carefully as it contains
important safety messages.
WARNING
MOVING OBJECT, PINCHING OBJECT HAZARD
Do not disassemble or modify the unit by yourself.
ELECTRIC SHOCK
Do not touch the inside to avoid electric shock.
ELECTRIC SHOCK
Maintain ground to avoid electric shock or fire.

©2018 HORIBA UK Ltd
Product Handling Information
Operational Precautions
Use of the equipment in a manner not specified by the manufacturer may impair the protection
provided by the equipment. It may also reduce equipment performance.
•If trouble occurs, contact either HORIBA service section or the dealer where the
equipment was purchased.
Post Test
When tests are finished the CFO system must be disconnected from any gas lines. This will
prevent the following;
•Damage to the system
•Leakage of dangerous gases
Disposal of the Product
When disposing of the product, follow the related laws and/or regulations of your country for
disposal of the product.

©2018 HORIBA UK Ltd
Contents
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Principle of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
The Critical Flow Orifice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Pre-Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Visual Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Test Preparation & Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Interpreting Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Error Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

1 ©2022 HORIBA UK Ltd
Overview
Introduction
The purpose of this guide is to describe the equipment and guide required to perform a
Propane Injection test to verify the accuracy and integrity of the Constant Volume Sampler
(CVS).
A known mass of propane gas is injected into the system and is compared to the mass
indicated by detection of a Flame Ionization Detector (FID). This test guide is commonly
referred to as a CFO Injection. The calibration verification is performed weekly, or after any
maintenance which could alter calibration, to ensure that the equipment has not shifted out
of acceptable tolerance limits.

2 ©2022 HORIBA UK Ltd
Principle of Operation
Constant Volume Sampler Checks:
The procedure for checking the overall accuracy of the Constant Volume Sampler (CVS) is
to introduce a known amount of a test gas (usually propane) into the exhaust system and
compare the calculated concentration with that indicated by an approved hydrocarbon
analyser. The gas is introduced via a calibrated orifice as provided in the CFO kit.
The volumetric flow rate through a standard CVS- CFV (critical flow Venturi) is given thus:
=󰇡
󰇢×60 (1)
Where:
V= Volume in standard cubic feet. This is read from the CVS control panel.
t= Time interval in seconds read from the CVS control panel.
60 = Conversion constant to yield Qin standard cubic feet per minute.
If qis the flow in SCFM of the sample gas as injected by the CFO, then the computed
sample gas concentration is:
 =󰇡
󰇢× 3(2)
*multiply computed sample gas concentration by 3 if Cobs in equation (3) below is measured
in ppm carbon instead of ppm propane. The system error in percentage is given as:
=󰇧󰇡
󰇢1󰇨×100 (3)
Where Cobs is the measured concentration in the bag sample obtained during the run.

3 ©2022 HORIBA UK Ltd
The Critical Flow Orifice Principle
The flow rate of a gas through a given orifice is given determined by the inlet pressure,
temperature and the outlet or backpressure on the orifice. For given inlet conditions, as the
backpressure is decreased, the gas velocity in the orifice throat and hence the flow rate,
continues to increase. At a sufficiently low backpressure (approximately 0.5 the inlet
pressure) the throat velocity reaches sonic conditions and further decrease on the back
pressure would have no effect on the flow rate. This is the so called “choked or critical flow”
condition. The practical advantage of operating a metering orifice in critical flow is that the
flow rate is determined from a single high pressure level reading and is not affected by
changes in backpressure.
It can be shown that for an ideal gas the critical flow rate would be
=××
(4)
Where
q= Flow rate.
K = Constant derivable from the gas constant and the specific heat ratio.
A= Orifice throat area.
P= Inlet absolute pressure.
T= Inlet absolute temperature.
Note that the flow rate varies directly with the inlet pressure. Because of real gas effects and
the inability to precisely measure A, equation (4) cannot be directly applied in practice and it
is necessary to calibrate each orifice individually. The apparatus used for this purpose
consists of essentially of an accurately ground glass cylinder provided with a loosely fitting
plastic piston. The piston has a circumferential slot filled with mercury which provides a low
drag gas seal against the cylinder bore. In use the gas to be measured pushes the piston
upwards and the time of travel between two precisely known levels is measured to 0.01sec.
Using this time measurement and the measured pressure and temperature of the gas in the
cylinder, the delivery rate in CFM through the orifice is calculated. The calibration accuracy
is better that 0.3%.

4 ©2022 HORIBA UK Ltd
Flow data are obtained for a range of inlet pressures and a least square curve fit is made .All
kits have first degree and second degree curve fits applied to the data for propane. Use the
first degree fit when calculating data manually; use the second degree fit when a
microprocessor is used for calculations. The corresponding orifice calibration is of the
form:
First degree:
=+×
()(5)
Second degree:
=+(×)+×
()(6)
Where:
q= Flow rate in SCFM at 29.92” Hg and 528°R.
A, B, C= Calibration constant furnished with each kit.
P= Absolute orifice inlet pressure, PSIA which equals gauge reading + (0.4912 x
Barometer, inches of Mercury).
T= Orifice inlet temperature, °F.

5 ©2022 HORIBA UK Ltd
Pre-Operation
Precautions
Before taking further steps, ensure that:
•The test cell floor is checked for fuel spills.
•The CVS blower must be operating when performing the test.
•Cylinders containing compressed gases are used for this procedure. The technician
must be familiar with the “Customer Site Safety Manual” sections dealing with the safe
handling, storage, and use of compressed gas cylinders.
•Safety precautions must be followed when using compressed gases.
•The CFO kit must be in the test cell prior to the start of the calibration for a minimum` of
20 minutes to ensure the kit is at room temperature.
Visual Inspection
•Ensure the test cell floor is checked for fuel spills.
•There should be no running vehicle(s) on the dynamometer(s) and the test cell door is
closed.
•The test cell air handler should be on and test cell ambient conditions are stable. The
gas cylinder and equipment is checked for leakage, damage, and cleanliness.
•The CFO pressure display should read barometric while the kit is not operating.
•Calibrations are checked as valid by verifying that the calibration due dates have not
been exceeded for the CFO kit.
•The power is turned on for the HC analyser (i.e. FID) and related equipment. The FID is
lit and allowed to warm-up for a minimum of 30 minutes.

6 ©2022 HORIBA UK Ltd
Test Preparation & Execution
Hardware
•Ensure that the air handling system in the test cell is turned on and test cell ambient
conditions are stable.
•Ensure that the CVS Blower is turned on.
•Connect CFO Kit output hose to LLRMT (low loss remote mixing tee) mixing point
provided.
•Connect the Propane cylinder hose to CFO Kit Inlet port. These are colour coded to
prevent operator error.
•Open the regulator and ensure that the outlet pressure is > 7bar (100psi). This is to
ensure that the correct target ppmC can be achieved. Lower outlet pressures can be
used; however the customer must adjust the target ppmC to a lower value.
•Check the gas cylinder and equipment for leakage, damage, and cleanliness.
•Connect the supplied LAN cable to the CFO Kit and the other end to the LAN port on the
LLRMT.
•Connect the supplied power adaptor to the 13amp mains socket on the LLRMT and in
turn use this to power on the CFO Kit. Make sure the extraction fan on the CFO kit is
working.

7 ©2022 HORIBA UK Ltd
Software
Auto Mode
1. Open CFO host software
2. Ensure no alarms are shown
3. Input CVS flow rate & Target PPM
4. Click on System Icon & choose Run
CFO will begin flowing gas through the system and into the CVS
End test when required by selecting Standby.
Manual Mode
1. Open CFO host software
2. Ensure no alarms are shown
3. Click on System Icon & choose Manual Mode
Under Orifice Settings,
4. Select gas type
5. Specify orifice size to use (low, high, low & high)
6. Input pressure value in psiA
CFO will begin flowing gas through the system and into the CVS
End test when required by selecting Standby
See figure 1 on next page for overview of software layout

8 ©2022 HORIBA UK Ltd
Figure 1 – Main Screen
Click for
Alarms (2)
Click for Version
info (1)
Click for
Operation Mode
(3)
Click for
CFO
Maintenance
Options (4)
Click for
Test Tools
(5)

9 ©2022 HORIBA UK Ltd
(1)
Order of Info
- Software Version
- Firmware Version
- CFO Serial Number
(2)
Order of Info
- Alarm Level
= Action Needed
- Description of Alarm
- Alarm State
High = Action Needed
Normal – Warning
- Time of Alarm
(3)
Order of Info
- Run - All Valves Activated
- Standby - APR closed
- Pause - All Valves Closed
- Manual Control – Activates Manual Mode

10 ©2022 HORIBA UK Ltd
(4)
Order of Info
- Service – features for service
personnel only
- SBC LAN Interface Settings
Setup custom IP address for CFO
- Alarm Set Points
Set when Alarms will flag up e.g. temperature range
(5)
Order of Info
- Logging – To log data

11 ©2022 HORIBA UK Ltd
Interpreting Results
Assuming ±2% accuracy in the calibration bottles and ±1% in the CVS pump absolute air
flow calibration, it follows that a value for Ein equation (3) earlier of ±3% or less can be
expected. Larger discrepancies from this would require corrective action.
Error Analysis
Following is a list of possible sources of error as based on the sign of the final result.
Positive Error:
•Venturi flow rate is less than the calibrated value.
oOriginal bulk stream calibration in error, or
oLeakage has developed between blower and Venturi
•Venturi inlet temperature transducer is reading low
•Venturi inlet pressure transducer is reading high
•Background concentration reading is too low. Check analyser zero.
•Barometer reading is high, check the pressure transducer.
•Flow computer output is high.
Negative Error
•Venturi flow rate is greater that calibration value
oOriginal bulk stream calibration in error or,
oLeakage has developed between vehicle inlet and the inlet to the bulk stream
Venturi.
•Venturi inlet temperature transducer reading high.
•Venturi inlet pressure transducer reading low.
•Background concentration reading is too high.
•Analyser is reading too low. Check analyser span.
•Barometer is reading too low, check the pressure transducer.
•Air leak into the bag sampling system, between the bags and the bag sample pump.

12 ©2022 HORIBA UK Ltd
Ensure location of CFO Outlet Pipe is as far into the Transfer Tube as possible
Maintenance
In order that the equipment stays in calibration and maintains accuracy, it should be kept
away from EMC sources. The unit should not be dropped or thrown around and care should
be taken during its transport.
Because of the very small size of sample gas orifice, precaution should be taken to maintain
cleanliness in the gas line system leading to the kit inlet connection.
The gas outlet should be kept clean to avoid introducing Hydrocarbons other than the
propane injected. The filter in the kit would take care of particulates but can pass moisture or
Oil vapour, which in form deposits in the Orifice.
The connecting gas lines should be stored in the case when not in use. If contamination is
suspected, the connecting lines should be rinsed with acetone and blown out with clean, dry
gas, such as bottled air or nitrogen.
If the unit has been exposed to contamination, or if for any other reason, a change in flow
characteristic is apparent, the complete unit should be returned for recalibration to HORIBA
UK Limited.
Inlet Duct
CVS
Inlet Duct
CVS
CFO
CFO

13 ©2022 HORIBA UK Ltd
It is highly recommend the kit is returned to HORIBA UK Limited for calibration
annually to compensate for any drift in the pressure, temperature of flow calibrations.
Reference: Projected C3H8 concentrations vs CVS flow (Indication Only)