Riken Keiki Marine Gas Detection
Spare Parts Supplier
Portable GX & RX instruments · fixed SD and SC detection · sensor cells and calibration items
The Riken Keiki instruments behind most gas detection enquiries
Riken Keiki is a Japanese manufacturer of gas detection instruments with a marine product line, and that line reaches a ship in two quite different forms: portable instruments carried by the crew, and fixed detection wired into the vessel's own alarm arrangement. One vessel commonly holds several at once — a compact instrument for enclosed-space entry testing, a larger pumped portable for tank work, and fixed detectors or a gas sampling system covering spaces nobody enters routinely. Riken Keiki states ATEX, MED, ABS, DNV, KR and RINA certification for its marine gas sampling systems, and lists MED among the approvals of portables such as the GX-3R Pro and the GX-9000; the approval held by an individual instrument is read from its own label and certificate. The model name alone rarely settles a parts question, because the same body is built with different sensor fits.
GX-3R and GX-3R Pro — compact personal instruments
Small enough to be worn rather than carried. The Pro can be configured for as many as five gases, combining LEL, oxygen, hydrogen sulphide and carbon monoxide with a toxic option such as HCN, NH3, NO2, PH3, SO2 or CO2, which is why two instruments with the same name on the case can need entirely different cells.
Multi-gas and VOC portables
The GX-6000 covers as many as six gases including volatile organic compounds, which brings a different sensor family into the same instrument. The GX-Force is a four-gas instrument. Both are ordered by the gases actually fitted rather than by the maximum the body will accept.
GX-9000 and GX-9000H — expandable four to six gas
A pumped instrument that detects up to six gases at once, with catalytic, thermal-conductivity, infrared, electrochemical or photo-ionisation sensors depending on the build, so which slots are filled is read from the instrument itself rather than assumed from the series. The GX-9000H is the model of the same series for high-concentration hydrogen sulphide and takes up to four gases, so the range, not only the gas, has to be stated when a cell is requested. Riken Keiki also lists a marine spare parts box among the GX-9000 options.
RX-8500 — methane by %LEL and by volume
A pumped instrument of Riken Keiki's RX-8000 series that reads methane by infrared both as %LEL and as percentage by volume, alongside oxygen, carbon monoxide and carbon dioxide; Riken Keiki notes that it can measure residual carbon dioxide in a tank under repair. An infrared sensor is a different part from the catalytic element used elsewhere for combustibles, and is treated as its own line on an enquiry, as are the oxygen and carbon monoxide cells.
SD-1 — smart transmitter and detector head
A fixed smart transmitter and detector series in which the letters after SD-1 name the sensing principle: the plain SD-1 is catalytic for combustibles, SD-1RI infrared for combustibles, SD-1OX oxygen and SD-1EC electrochemical for toxic gases, and a D, as in SD-1D, marks the suction version of a diffusion head. Each version works on one principle, so the full designation from the label decides which sensor is meant; the transmitter and the sensor are raised as separate lines on an enquiry.
SC-01 — single toxic-gas monitor
A battery-powered diffusion monitor built around smart interchangeable sensors for one toxic gas at a time: chlorine, carbon monoxide, hydrogen sulphide, hydrogen cyanide, ammonia, phosphine or sulphur dioxide. Riken Keiki now lists the SC-01 as discontinued, so most enquiries concern the sensor for the fitted gas, and the target gas and range are the decisive fields on the RFQ line rather than the monitor type.
SD-3 — gas detectors with signal converter
A fixed detector series carrying Riken Keiki's F Sensor series: SD-3RI is infrared, for combustible or toxic gas, SD-3EC electrochemical, for toxic gas or oxygen, SD-3DRI the suction version and SD-3SC with a GD-3 sensor head the remote version. For ships Riken Keiki also builds gas sampling systems covering water ballast tanks, pump rooms and accommodation, so a fixed-system enquiry usually reaches a supplier as a list of heads, sensors and calibration items for several spaces at once rather than as a single part.
Riken Keiki portable gas detectors: testing a space and wearing a monitor are two jobs
SOLAS regulation XI-1/7 requires ships to carry portable atmosphere testing instruments able to measure, as a minimum, oxygen, flammable gases or vapours, hydrogen sulphide and carbon monoxide before anyone enters an enclosed space. A space is tested from outside before entry, with the sample drawn through a hose, while a crew member inside wears a monitor of their own. A ship's portable Riken Keiki instruments therefore usually split into two groups, and a parts request reads differently for each.
Drawing a sample from outside the space
Pre-entry testing means drawing the atmosphere through a probe and hose while the person reading it stays outside. On a pumped instrument such as the GX-9000 or the RX-8500, or a GX-3R with its clip-on RP-3R pump, the request covers the whole sampling path: pump unit, probe, hose and the dust and water filters that protect it. A clogged or wet filter cuts the sample flow, so filters are ordered in numbers rather than one at a time.
The instrument that goes in with the crew
A compact GX-3R or GX-3R Pro worn in the breathing zone samples by diffusion and alarms on the person carrying it. Its lines are the sensor cells for the gases actually fitted, the battery pack, the intake filter over the sensors, and the rubber boot or body cover that takes the knocks of tank and void-space work.
Calibration items and consumables
The IMO guidelines expect the maker's manual to set clear calibration requirements, so calibration gas of the right mixture, calibration adapters and docking-station items belong on the same request as the cells. Vessel Core supplies these as parts; the calibration itself is carried out on board or by a service provider to the maker's instructions.
Riken Keiki components that appear on RFQ lines
Most of what actually reaches a supplier for this equipment class is consumable rather than instrument. The groups below follow the order in which the parts are handled on board — the sensing element first, then the sampling path that feeds it, then power, then everything needed to prove the reading is still true.
- Replacement electrochemical sensor cells for toxic gases
- Oxygen sensor cells
- Catalytic sensing elements for combustible gas
- Infrared sensor units for methane and other hydrocarbons
- Interchangeable smart sensors for SC-01 monitors and SD-1 heads
- Sampling pump units for pumped instruments
- Dust and water intake filters
- Sampling hoses and probes
- Battery packs
- Chargers and charging docking stations
- Calibration docking stations
- Calibration gas cylinders — span gas
- Zero air cylinders
- Calibration adapters
- Rubber boots and body covers
- O-rings and gaskets for sensor and case sealing
Portable gas detector — general arrangement
A licensed photograph of Riken Keiki equipment was not available at publication, so this technical reference illustrates the general arrangement shared by this equipment class.
Illustrative technical reference, not a photograph of Riken Keiki equipment or a Vessel Core installed reference — a licensed photo was not available. Vessel Core has no dealership, distribution or partnership agreement with the manufacturer named; it operates as an independent spare parts supplier.
Turning a GX or SD designation into a quotable line
Part numbers help, but they are rarely to hand once an instrument has been in service for a few years and the paperwork has followed a previous crew ashore. A photo of the rating label, the model designation on the fascia and the gas markings around the sensor block are often enough to begin narrowing a cell or a filter before a supply route is proposed. Where the case is already open, the marking on the cell itself settles most of what is left.
- Complete model designation as printed on the fascia or label, including any Pro or H suffix and, on fixed heads, the letters after SD-1 or SD-3 (RI, EC, OX, a D for suction, SC for remote), which name the sensing principle and sampling method
- Serial number from the rating label, photographed square-on; Riken Keiki's own marine enquiry process asks for the Inst. No. and the IMO number, so photograph every number on the label
- Target gas or gases, and the measuring range for each channel
- Sensor principle where known: electrochemical, catalytic or infrared
- Whether the instrument samples by diffusion or draws through a sampling pump, built in or clipped on as an RP-3R on the GX-3R series
- Sensor slot layout on expandable instruments such as the GX-9000
- Marking on the sensor cell itself where the case is already open
- Condition of the intake filters, and whether they are being renewed at the same time
- Concentration and gas type of the calibration cylinder in use on board
- Fixed or portable duty, and the space the instrument serves
- Whether the model is one Riken Keiki now lists as discontinued, such as the GX-6000 or the SC-01, which changes what can still be supplied for it
- Quantity, vessel and IMO, port and ETA
Tools for this equipment: the Ex marking reader for the explosion protection marking on the instrument label and the IP code reader for its enclosure rating. For a combustible reading in % LEL or a toxic one in ppm, the gas concentration converter gives the same figure in % vol and mg/m3, with the LEL from the calibration certificate.
A gas detector is ordered by its sensor, not by its model name.
These instruments are defined by the sensor fit rather than by the series, so an RFQ line that names only the model leaves the important field blank. What follows is how that single fact — a body that accepts more than one sensor — changes the questions asked before any Riken Keiki item is quoted.
Target gas stated with the model
A GX-3R Pro built for LEL, oxygen, hydrogen sulphide and carbon monoxide plus a toxic option, and one built for a different toxic option, are the same instrument with different cells. The gas is asked for in the same breath as the model, before anything is looked up.
Range asked before the cell
The GX-9000H is a high-range hydrogen sulphide variant aimed at oil tankers, so the same gas can mean a different part on two instruments that sit side by side in the same locker. The measuring range is treated as part of the description, not as a detail.
Sensing principle confirmed
Electrochemical cells for toxic gases and for oxygen, catalytic elements for combustibles, and infrared sensors such as the methane sensor on the RX-8500 or those in the SD-1RI and SD-3RI heads are separate part families. Confirming the principle avoids quoting the right gas on the wrong technology.
Smart sensors treated as consumables
Riken Keiki builds the SC-01 around smart interchangeable sensors and describes the SD-1 as a smart transmitter, which makes the sensor the item that is changed rather than the instrument. That moves the sensor onto the running-spares list rather than into a workshop job; any setting needed after a change is read from the instrument's own manual.
Sampling path quoted together
On a pumped instrument the pump unit, the dust and water intake filters, the hose and the probe form one path. Renewing a pump while leaving a blocked filter in place is a common way to open the same instrument twice, so the group is raised as a set of separate lines.
Certification read at maker level
Riken Keiki states ATEX, MED, ABS, DNV, KR and RINA certification for its marine gas sampling systems, and lists approvals model by model for its portables and fixed heads. That is repeated here as manufacturer information; the certification status of an individual instrument or sensor is a question for the maker's own documentation, not something a parts enquiry can settle.
Riken Keiki gas detection enquiries — recurring questions
Can Vessel Core quote Riken Keiki gas detector parts without a part number?
Often yes. A photo of the rating label, the model designation on the fascia, the gas markings around the sensor block and, where the case is already open, the marking on the sensor cell itself are usually enough to begin structuring the RFQ before a full part number is available. Stating the target gas and the measuring range alongside the model removes most of the remaining ambiguity.
What information is needed for a GX-series sensor cell enquiry?
The instrument model, the serial number from the rating label, the target gas and its measuring range, and the sensor type where it is known, since an electrochemical cell for a toxic gas, an oxygen cell and a catalytic or infrared element for combustibles are different parts. It is worth saying whether the instrument draws through a sampling pump, because the pump unit, its intake filters and the sampling hose are normally reviewed on the same enquiry.
Can a sensor be changed on an SC-01 without reconfiguring the monitor?
Riken Keiki describes the SC-01 as built around smart interchangeable sensors, so the sensor, not the monitor, is what is changed and ordered; whether the monitor needs any setting after a change is confirmed from the SC-01 manual. Riken Keiki now lists the SC-01 as discontinued, which makes the sensor for the fitted gas the usual enquiry, and the RFQ has to state the target gas and its range, because the monitor body accepts more than one sensor and the cell is what is actually being ordered.
Does Vessel Core handle fixed SD-3 system parts as well as portable detectors?
Yes. Fixed detection such as SD-3 and SD-1 series detectors, and the gas sampling systems Riken Keiki builds for water ballast tanks, pump rooms and accommodation, is handled alongside portable GX-series and RX-8500 requests. A vessel often carries both, and the calibration gas, adapters and sensor cells behind them overlap.
Can Vessel Core review OEM-route and verified alternative routes for Riken Keiki gas detection parts?
Yes, with one distinction that matters on this equipment. Filters, sampling pump parts, hoses, probes and calibration items can be reviewed on an OEM-route basis or as a verified alternative where the approval context allows it. Sensor cells for a certified fixed installation are different: the detector's approval is tied to the cell it was type-tested with, so the OEM route is normally the one to confirm first and any alternative has to be checked against the approval before it is offered. The route reviewed is recorded per RFQ line.
Which Riken Keiki portable gas detection parts are worth carrying on board as spares?
Mostly the items that the sampling path and the sensors consume: dust and water intake filters, sensor cells for the gases actually fitted, battery packs, sampling hoses and probes, and the calibration gas and adapters the manual calls for. On pumped instruments the pump unit is a wear item in its own right. The instrument model, the target gases and their ranges decide which cells and filters are meant, so they belong on every line.
Does Vessel Core calibrate Riken Keiki portable gas detectors?
No. Vessel Core supplies parts only: sensor cells, filters, batteries, sampling items, calibration gas and adapters. Calibration, and any setting after a sensor change, follows the maker's instructions and is done on board or by a service provider; the request should still name the calibration gas in use, so that the cylinder and the adapter match the instrument.
Is Vessel Core connected to Riken Keiki?
No, and there is no agreement of any kind. Vessel Core holds no dealership, distribution, representation or partnership agreement with Riken Keiki, and quoting a component against one of its designations implies no approval by the maker and no claim of interchangeability.
Send the rating label and the target gas.
List the instrument model, the serial number where the label is still legible, the target gas and its range, the components required and the port. Sensor cells, intake filters, sampling pump units, battery packs, docking stations and calibration items are then quoted as separate lines, so the ship can decide what to change now and what to carry as a running spare.
