Riken Keiki GD-F4A-A User manual

PT2E-2501
Oxygen Gas Detector Head
GD-F4A-A
Operating Manual
(PT2-151)

Operating Precautions
This detector is an oxygen deficiency detector that detects oxygen in the air and triggers an oxygen
deficiency alarm.
The oxygen deficiency detector is a safety unit, not an analyzer or densitometer which performs
quantitative/qualitative analysis/measurement for oxygen.
Please fully understand the following points before using it, so that it can be used properly.
1. The readings of the detector fluctuate slightly in response to changes in the air pressure.
In particular, be careful of alarm activation when a low air pressure is brought in by typhoon. In
addition, it may be fluctuated by environmental (temperature, humidity etc.) changes in the
installation site.
2. The alarm must be set within a range where the performance of the detector can be ensured.
The standard alarm setpoint value is 18 vol%.
3. This is a safety unit, not a control unit.
The alarm contact output of the detector must be used for an external alarm lamp/buzzer, while the
analog signal output must be used for an indicator or external recorder.
4. For maintenance of the detector, it must go through a regular maintenance, including replacement
and adjustment of the regular replacement parts as specified in the operating manual. In addition,
because this is a safety unit, it is recommended that a regular maintenance and span adjustment are
performed every six months.

1
TABLE OF CONTENTS
１．PRODUCT OUTLINE
１－１． Preface ……………………………………………………………………… 2
１－２． Application for use …………………………………………………………… 2
１－３． Definition of DANGER, WARNING, CAUTION and NOTE ………………… 2
１－４． Method of confirmation for CE/UKCA marking type
(Non-explosion proof specification only) ………………… 2
２．IMPORTANT INSTRUCTIONS FOR THE SAFETY
２－１． Danger cases ………………………………………………………………… 3
２－２． Warning cases ………………………………………………………………… 3
２－３． Precaution …………………………………………………………………… 3
２－４． Caution for explosion proof (In case of intrinsically safe design) ………… 3
３．PRODUCT COMPONENTS
３－１． External dimensions ………………………………………………………… 4
３－２． Names and functions for each part ………………………………………… 5
３－３． System composition ………………………………………………………… 6
４．HOW TO USE
４－１． Before operation …………………………………………………………… 8
４－２． Installation place …………………………………………………………… 8
４－３． Maintenance space ………………………………………………………… 8
４－４． Installation work …………………………………………………………… 8
４－５． Caution at wiring construction …………………………………………… 9
４－６． Applicable cable …………………………………………………………… 9
４－７． Example of cable connection ……………………………………………… 9
４－８． Caution at piping works ……………………………………………………… 10
４－９． Example of piping connection ……………………………………………… 11
５．OPERATION METHOD
５－１． Preparation for start up …………………………………………………… 12
５－２． Start up ……………………………………………………………………… 12
５－３． Stopping the operation ……………………………………………………… 12
６．MAINTENANCE AND INSPECTION
６－１． Inspection frequency and items …………………………………………… 13
６－２． How to calibration
６－２－１． Required kit and tools for calibration …………………………… 14
６－２－２． Performing a zero adjustment …………………………………… 14
６－２－３． Performing a span adjustment …………………………………… 14
６－３． Replacing the sensor
６－３－１． Replacement frequency of the sensor ………………………… 15
６－３－２． How to replace the sensor ……………………………………… 15
６－４． List of recommendable spare parts for regular replacement …………… 16
７．STORAGE, RELOCATION AND DISPOSAL
７－１． Procedures to store the detector head or leave it for a long time ……… 17
７－２． Procedures to relocate the detector head or use it again ……………… 17
７－３． Disposal of products ……………………………………………………… 17
８．MEASURES AT ABNORMAL CASE
８－１． Responding to trouble alarm ……………………………………………… 18
８－２． Before it is thought to be a trouble ……………………………………… 18
９．PRODUCT SPECIFICATIONS
９－１． Standard specifications ………………………………………………… 19
９－２． Standard accessories …………………………………………………… 19
９－３． Optional accessories …………………………………………………… 19
９－４． Detection principle ………………………………………………………… 20
１０．DEFINITION OF TERMS …………………………………………………………… 21

2
１．PRODUCT OUTLINE
１－１．Preface
Thank you for choosing our fixed type Oxygen Detector Head GD-F4A-A. Please check that the model
number of the product you purchased is included in the specifications on this manual.
This manual explains how to use the detector and its specifications. It contains information required for
using the gas detector properly. Not only the first-time users but also the users who have already used
the product must read and understand the operating manual to enhance the knowledge and experience
before using the detector.
１－２．Application for use
This is a suction type oxygen detector head applying the galvanic cell type oxygen sensor and is used in
combination with indicator / alarm unit to show oxygen content. Read the instruction manual for
indicator / alarm unit as well as this manual.
This unit is designed as drip-proof construction for outdoor installation.
Also, it can be used as intrinsically safe system in combination with zener barrier (option) to be able to
install in hazardous area.
１－３．Definition of DANGER, WARNING, CAUTION and NOTE
This manual contains the following headings to ensure the safe and effective operation.
This message indicates that improper handling may cause serious damage on
life, health or assets.
This message indicates that improper handling may cause serious damage
on health or assets.
This message indicates that improper handling may cause minor damage on
health or assets.
This message indicates advice on handling.
１－４．Method of confirmation for CE/UKCA marking type
(Non-explosion poof specification only)
The CE/UKCA marking is labeled on the detector in case of comply with CE/UKCA mark (Non-explosion
poof specification only). Please confirm the instrument specification before using. Please refer Declaration
of Conformity that is at the end of this manual if you have CE/UKCA marking type.
You can confirm instrument specification to see the CE/UKCA mark as follows.
DANGER
WARNING
CAUTION
* NOTE
CE/UKCA mark
CE/UKCA mark label
(Non-explosion poof specification only)

3
２．IMPORTANT INSTRUCTIONS FOR THE SAFETY
２－１．Danger cases
２－２．Warning cases
２－３．Precaution
２－４．Caution for explosion proof (In case of intrinsically safe design)
In case of non-explosion poof system, do not use this unit at the place where combustible gas may exist.
・Do not cut the wire for protective ground both inside and outside of instrument. Or, do not disconnect the
connection of the ground terminals.
・Before starting the operation, check if any defect is not found on the protective grounding.
・If there is any defect on the protective functions such as protective grounding, do not start the operation.
・It is very dangerous if the instrument gives oxygen deficiency alarm.
Take appropriate measures based on your judgment at that time.
・Perform gas calibration at proper interval.
・Do not change or remodel the circuit/structure of this unit.
・Do not disassemble the sensor since there is a electrolyte inside.
If your finger touches the electrolyte, wash your finger way with water immediately.
WARNING
・Do not use a walky-talky around the instrument.
The indication might be affected by the electromagnetic wave generated by the walky-talky if it is used near
the instrument. When the walky-talky is used, be away enough from the instrument not to affect.
・Do not control other equipment by using outputs of this detector.
This is not a control equipment. It is prohibited to control other equipment by using outputs of this
detector.
CAUTION
・Do not use this detector head expect for the measurement of oxygen content in a mixture of air and
combustible gas or vapors, or a mixture of air and toxic gases.
・When cleaning this unit, do not use dry cloth but use the wet cloth not to change the static electricity on plastic
part.
DANGER
DANGER

4
３．PRODUCT COMPONENTS
３－１．External dimensions
Cable inlet
Cable inlet Sensor
Gas inlet
Protective
ground
Gas outlet
(For U-bolt)
Cable inlet Sensor
Gas inlet
Protective ground Gas outlet
(For U bolt)

5
３－２．Names and functions for each part
① Oxygen sensor : Galvanic type sensor to detect oxygen content.
② Sensor retainer : This is a retainer to hold the oxygen sensor
(equipped with filter inside).
③ Sensor lead : Lead wires for oxygen signal outputs.
④ Terminal strip : Relayed terminal for sensor lead and external cable.
⑤ Cable gland : Entrance to lead the cable (φ8～φ11mm) from outside.
⑥ Hinge : Hinge for front door.
⑦ Lock : Lock for front door.
⑧ Mounting hole : Mounting hole to fix this unit on the wall surface.
⑨ Protective earth bolt : Bolt for protective grounding.
⑥
⑨ ⑤
③
⑦
①
②
④ ⑧

6
３－３．System composition
(1) Intrinsically safe system
１．The oxygen detector shall be used as following composition.
２．The safety retainer to be connected with oxygen detector shall have linear characteristics and be passed
the type approval as it is.
Also it shall satisfy the following conditions.
(1) Rating of safety retainer
Max voltage of intrinsic-safety circuit : Below 28V
Max current of intrinsic-safety circuit : Below 600 mA
Max power of intrinsic-safety circuit : Below 0.75W
(2) Performance division and group
Performance division : ia
Group : ⅡC
(3) Relations between allowable inductance (Lo) and allowable capacitance (Co)
of intrinsic-safety circuit, and external wiring inductance (Lw) and capacitance(Cw)
of intrinsic-safety circuit.
Lo ≧ Li + Lw
Co ≧ C + Cw
(4) When making wiring connection for intrinsic-safety circuit, take care not to induce an electric
current and voltage which will spoil the performance of intrinsically safe by the electromagnetic
induction or electrostatic induction to the intrinsic-safety circuit.
WARNING
！
Detector
head
Zener barrier
Indicator
/alarm
unit
Hazardous area Non-hazardous area
CVVS-2C 1.25mm2 or equivalent (max 600m) cable
Hazardous
area
Non-hazardous
area
Safety retainer
Oxygen detector
Ｌｉ≒ 0
Ｃｉ≒ 0
≒ 0 shows a negligible value
Ｌｉ
Ｃｉ
Ｌｏ
Ｃｏ
Ｌｗ
Ｃｗ

7
(2) Non-explosion proof system
(3) Component inside detector head
Drip-proof housing
Sensor lead
Terminal strip
Cable gland
Shielded cable
Oxygen
sensor
Gas inlet
Gas outlet
Detector
head
Indicator/alarm unit
Non-hazardous area Non-hazardous area
CVVS-2C 1.25mm2 or equivalent (MAX 600m)

8
４．HOW TO USE
４－１．Before operation
All persons who use this detector for the first time and who has even used the detector are requested to
follow all the instructions for use carefully. If not, the instrument may be defective and correct gas
detection may not be performed.
４－２．Installation place
This detector head is installed at the place of oxygen detection directly since this is a diffusion detector
head.
Note the following points.
Do not install the detector head and cable at the following points.
・Place to get direct rays of the sun.
・Places closed to high temperature and/or emission of electromagnetic wave.
・Place with vibration or shocks.
・Place where the mounting part is weak and it is easy to come out.
・Place where it is difficult to make maintenance and inspection.
・Place unable to secure grounding.
・Places where the temperature is drastically changed.
・Places exceeding operating temperature and humidity.
４－３．Maintenance space
A certain maintenance space must be secured around the detector head, so that the maintenance staff can
perform the safe and correct maintenance work. Pay due attention to secure this space during work plan
and execution.
４－４．Installation work
(1) Mounting to the wall surface
Mount the detector head to a flat surface (wall surface, etc)
with either M6 bolts or M10 bolts through mounting holes.
Refer to”3-1. External dimensions” for mounting pitch.
(2) Mounting to the pole
The unit can be mounted to the pole (2B pipe)
by using the optional U-bolts as show right figure.
(3) Installation to the outdoors
For outdoor installation, optional drip-proof cover is required
to keep reliable detection although this is a drip-proof design.
Contact authorized distributors, dealers or representative
appointed by RIKEN KEIKI Co., Ltd.
WARNING
Mounting to the pole
2B pipe
（O.D. 60.5mm）
U-bolt
（Nominal
diameter 50B）

9
４－５．Caution at wiring construction
４－６．Applicable cable
Signal transmission : CVVS 1.25mm2, 2C or equivalent
Transmission distance : Within 600m at total
Cable O.D. : φ8-φ11mm
４－７．Example of cable connection
(1) In case of non-explosion proof system
① Lead the applicable cable through cable inlet
and connect to the terminal strip.
② Connect the other end cable to the indicator/alarm unit.
③ Connect the shield’s drain wire at the indicator/alarm unit
to the ground.
(2) In case of intrinsically safe system
You can build the intrinsically safe system by adding
optional zener barrier between detector head and indicator/alarm unit.
① Lead the applicable cable through cable inlet and connect to the terminal strip.
② Connect the optional zener barrier between this unit and indicator/alarm unit at
non-hazardous area. (See below fig.)
③ Connect the other end cable to the indicator/alarm unit.
④ Connect the shield’s drain wire at the indicator/alarm unit to the chassis ground.
Example of intrinsically safe system
・When make wiring construction, take care not to damage the internal electronics circuit.
・When handle the detector unit, put it at horizontal position. If put it vertically, it tends to fall and
damage the detector.
・Power cable and signal cable shall not be laid down together with motive power cable such as motor,
etc.
・When use twisted cable, take care not to contact a part of core cable with other core cable.
CAUTION
！
ケーブルの接続
ケーブル
－＋
端子台
センサ
リード線
Sensor lead wire
Terminal
strip
Cable connection
1
3
24
Detector head
Indicator/alarm
unit
Zener barrier
（MTL7761Pac）
Max. 600m
Cable
Hazardous area Non-hazardous area
Connection cable
Connection
cable

10
４－８．Cautions at piping works
・ This unit is designed to sample the gas in an atmospheric pressure. Do not give an excessive pressure to
gas inlet and outlet of this unit.
・ Connect the exhaust pipe to the gas outlet located at the bottom of this unit and exhaust the sampled gas
to an area known to be non-hazardous.
WARNING
・ Use Φ8(O.D)-1t copper pipe and so on for piping.
・ Carry out piping works as straight as possible.
Excessively high load may cause burden on the suction pump, shortening the effective life of the pump.
When bends the pipe, secure R (radius of curvature) enough to avoid loading to the piping.
・ Determine the suction side piping length while considering the response time. When the gas is sampled
from the piping end (gas detection point), the response time of the gas detection sensor itself + delay time
caused by the piping length becomes equivalent to the detector response time.
・ Be sure to attach the gas suction port at the end of gas detection point.
・ Be sure to put dust filter in front of gas detector. If sampled gas contains water and corrosive gases,
removal device is required separately.
・ Do not alter, noｒ remodel the parts, etc.
・ Use the circuit breaker as for the power of indicator/alarm unit. Also it shall be mounted nearby
indicator/alarm unit and be specified that it is for power interruption of indicator/alarm unit.
・ Ground the zener barrier separately corresponding to the A-class grounding with ground resistance of
10Ω or less.
・ Use the specified cable.
・ For system installation, operation and maintenance, take care not to damage the intrinsically safe
design.
・ The power of the indicator/alarm unit shall be turned on after completion of all wirings. If each wiring is
carried out in the power on condition, short-circuit between terminals or an electrical shock may be
occurred.
* NOTE
When wiring, read the operating instructions for the connected indicator/alarm unit.
WARNING
CAUTION
CAUTION

11
４－9．Example of piping connection
Gas inlet/outlet fitting of this unit is Rc 1/8 female screw and provided with brass coupling.
Applicable piping is φ8(O.D.)-1t copper pipe. Secure the piping connections not to leak.
The piping material will be changed depending on corrosive gas contained in a sampled gas. In such case,
contact RIKEN KEIKI Co., Ltd.
(1) In case of pump suction
(2) In case of pressurized sample gas
(3) In case of aspirator suction
It is also possible to apply air aspirator unit to sample the gas by utilizing instrumentation air.
In this method, pressure to the sensor must be kept as small as possible and make it to
-26hPa at a maximum.
As the load to oxygen sensor is high on this method, aspirator suction method shall be used
only when the pump cannot be used.
If the sample gas pressure would fluctuate, use the constant flow rate control valve to keep
the constant flow rate.
Exhaust the sampled gas to open air in principle. When make piping to exhaust side
necessarily, choose the piping diameter to keep the pressure loss due to the length of piping
within 13hPa.
Detection
p
oint
GD-F4A-1
Gas OUT
1.0±0.3L/min
Dust filter
Pump
Flow control
valve
P
Flow meter
Dust filter
Detection
p
oint
GD-F4A-1
Gas OUT
1.0±0.3 L/min
Flow control valve
Flow meter
Detection
p
oint
GD-F4A-1 Instrumentation air
Air consumption：1～3NL/min
Pressure：0.1～0.34MPa
Dust filter Flow control
valve
Aspirator
Flow meter
CAUTION

12
５．OPERATION METHOD
５－１．Preparation for start up
Before making power on, take care of the following. If do not keep this, there is the danger of electrical
shock and damage of instrument.
５－２．Start up
①This detector head does not equip a power switch. Analog outputs of oxygen sensor are
transmitted to the indicator/alarm unit directly through the connected cable. As far as the cable
has been connected correctly, this system starts operation by putting on the power switch in
indicator/alarm unit.
②Let the gas flow to be sampled to this unit by turning on the pump switch etc.
③Adjust the flow-rate to lead sampled gas to 1.0L±0.3mL/min.
④Be sure to perform gas calibration at the time of new installation. Correct reading may not be
obtained before gas calibration.
５－３．Stopping the operation
① Stop the sample gas supply to this unit by turning off the pump switch, etc.
② This system stops operation by putting off the power in indicator/alarm unit, since this unit has no
power switch.
・ Make protective grounding.
・ Check that the wiring with outer unit is made correctly.
・ Check that the supply voltage is within the rating.
・ Check that the rated fuse is used.
・ At the new installation, adjust the reading in indicator/alarm unit according to 「6-2. Calibration」.
Adjustment is done by indicator/alarm unit since the detector head has no function for adjustment.
Refer to operating instructions for the connected indicator/alarm unit.
WARNING
CAUTION

13
６．MAINTENANCE AND INSPECTION
Gas detection and alarm instrument is kept in continuous operation over a long time and must perform a
vital role as a safety device. For this purpose, periodical inspection must be made. The High-pressure
Gas Safety Act in Japan sets forth the obligation of periodical inspection of the gas detection and alarm
instrument.
- Maintenance Contract –
Be sure to perform the regular maintenance inspection since this is an instrument for security and
safety. If this detector head founds defective, contact our nearest agent or RIKEN KEIKI soon.
６－１．Inspection frequency and items
The inspection includes a daily inspection which a person in charge of control and operation of the gas
detection instrument performs inspection before work once a day, and a monthly inspection carried out once
a month, and periodical inspections conducted by the service personnel designated by manufacturer. The
inspection items are confirmation of lights, concentration indication and alarm function on the indicator/alarm
unit side. It is also necessary to carry out gas calibration at least every 6 months. The law in Japan sets forth
that the unit must issue an alarm during the circuit inspection related to alarm while providing normal
operation, at least, once a month.
To maintain the safety operation of the gas detection instrument, it is recommended to keep the maintenance
contract with our authorized distributor for regular maintenance, adjustment and overhaul etc including the
gas sensitivity adjustment (gas calibration).
For the detail of maintenance contract, contact our nearest agent or RIKEN KEIKI.
・ This is a safety instrument and the inspection every 6 months or more is mandatory to ensure the
safety. If the unit is used by continuously without inspection, the sensor sensitivity may change,
resulting in failure of correct detection.
WARNING
・ Be sure to inform sections concerned beforehand when performing alarm test or gas calibration.
For the equipment connected with output signal from indicator/alarm unit, perform them after
disconnecting the output signal.
・Special trained engineer for gas detection instrument can perform maintenance work and inspection
accurately and efficiently. Then, it is recommended to contact our authorized agent for maintenance
and inspection.
＊ NOTE

14
６－２．How to calibration
Perform gas calibration at new installation, 6 months maintenance and sensor replacement.
６－２－１．Required kit and tools for calibration
Prepare following jigs and tools to perform zero and span adjustments.
Calibration gas (standard gas for zero and span)
Gas sampling bag for calibration gas.
Gas sampling bag for exhaust gas.
Suction pump to lead calibration gas
Flow meter with flow control valve (enable to control 1.0L/min).
６－２－２．Performing a zero adjustment
①Pack the zero gas (Nitrogen more than 99.9 vol %) into gas sampling bag.
②Disconnect piping for both gas inlet and gas outlet of this unit.
③Connect flow meter （with flow control valve） and suction pump to the detector head. Turn on the
pump and adjust the reading of flow meter to 1.0±0.3L/min.
④Connect gas sampling bag for calibration to the IN side of the pump and gas sampling bag for
exhaust gas to the outlet of this unit respectively.
⑤After reading by indicator/alarm unit gets stable, adjust the reading to zero with respective
potentiometer of indicator/alarm unit.
⑥Stop the supply of zero gas, disconnect gas sampling bag for calibration and confirm that the
oxygen reading returns to 20.9vol %.
⑦Return disconnected piping to where they were (completion of zero adjustment).
６－２－３．Performing a span adjustment
① Pack the span gas (fresh air for oxygen deficiency alarm instrument and their concentration is
around preset alarm level for other purpose) into gas sampling bag. For simple calibration, you
may be possible to use an ambient air as span gas containing 20.9vol% O2 providing that the
ambient pressure is 1 atm (1000±50hPa) and contamination in air is negligible against span gas
concentration.
② Disconnect piping for both gas inlet and gas outlet of this unit.
③ Connect flowmeter （with flow control valve） and suction pump to the detector head. Turn on the
pump and adjust the reading of flowmeter to 1.0±0.3L/min.
④ Connect gas sampling bag for calibration to the IN side of the pump and gas sampling bag for
exhaust gas to the outlet of this unit respectively.
⑤ After reading by indicator/alarm unit gets stable, adjust the reading to the span gas concentration
with respective potentiometer of indicator/alarm unit.
⑥ Stop the supply of span gas, disconnect gas sampling bag for calibration and confirm that the
oxygen reading is 20.9vol %.
⑦ Return disconnected piping to where they were (Completion of span adjustment).

15
６－３．Replacing the sensor
６－３－１．Replacement frequency of the sensor
To maintain the reliability of the measurement, it is recommendable to replace the sensor periodically.
Our oxygen sensor has an enough life span. However, the actual life is depending on the operating
conditions. Then, replace the sensor once a year as the tentative deadline for the replacement cycle.
６－３－２．How to replace the sensor
① Verify that the indicator/alarm unit is off. If the sensor is disconnected, the indicator/alarm unit
issues an alarm.
② Turn a lock of detector head and open the front door.
③ Loosen two screws at the top of terminal strip and disconnect two lead (black and white) wires.
④ Loosen the screw for sensor stopper and take off the sensor stopper.
Pull out the sensor upward from the holder
⑤ Insert new sensor into the holder and push the sensor until it comes to the end.
Mount the sensor stopper and fix it with screw.
⑥ Connect black and white sensor lead wires to the terminal strip. Connect white wire to positive (+)
terminal and black wire to negative (-) terminal respectively.
⑦ Close the front door of the detector head and fasten a lock.
・Be sure to carry out gas calibration after sensor replacement. If not, correct gas detection may not be
performed.
Lead-wire (black)
Negative side cable core
Lead-wire (white)
Sensor
Sensor stopper
Sensor holder
Positive side cable core Cable
CAUTION

16
６－４．List of recommendable spare parts for regular replacement
No. Name of parts Inspection frequency Replacement interval Q’ty/unit
1 O-ring
(sensor side in the holder) 1 year 3-6 years 1
2 O-ring
(Housing side in the holder) 1 year 3-6 years 1
* NOTE
・The replacement interval will change depending on operating condition and it does not mean the
warranty period.
Replacement interval changes according to the result of regular maintenance.

17
７．STORAGE, RELOCATION AND DISPOSAL
７－１．Procedures to store the detector head or leave it for a long time
The detector head must be stored under the following environmental conditions.
• In a dark place under the normal temperature and humidity away from direct sunlight
• In a place where gases, solvents or vapors are not present
７－２．Procedures to relocate the detector head or use it again
When the detector head is relocated, select a new place in accordance with “4-2. Installation place” and
“4-4. Installation works”.
For information on wiring work, see “4-5. Caution at wiring construction”. The unpowered time must be
minimized when the detector head is relocated.
７－３．Disposal of products
When the detector head is disposed of, it must be treated properly as an industrial waste in accordance
with the local regulations.
・ When using a relocated or stopped/stored detector head again, never fail to perform a calibration. For
information on readjustment including a calibration, please contact RIKEN KEIKI.
CAUTION

18
８．MEASURES AT ABNORMAL CASE
８－１．Responding to trouble alarm
If this detector founds defective, contact our authorized agent or RIKEN KEIKI.
８－２．Before it is thought to be a trouble
・Check the wirings around the related instruments as well as this detector head.
It may be caused by improper operation.
・Re-check the detection system and contact our authorized agent or RIKEN KEIKI.
It may be caused by cable disconnection, short circuit, etc.