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Brand: Tokyo Keiso
Tokyo Keiso FW-9000NN Servo Balance Tank Level Gauge
Description
Servo balance-type tank gauge with density and interface measurement
The Tokyo Keiso FW-9000NN (catalogue name FW9000NN series) is a servo balance-type level gauge and the successor to the FW-9000 series. A small displacer hangs on a thin measuring wire wound on a precision grooved drum. A stepping motor, controlled by a microprocessor, keeps the wire tension slightly below the displacer weight so that the displacer follows the liquid surface with a stable draft line, and the drum rotation gives the level.
By adjusting the control tension the same instrument can measure the interface between two liquids, and by sinking the displacer it can measure liquid density at a point or at several points for a density profile. Tokyo Keiso lists LPG, LNG, petroleum, fuels, water supply and sewage, chemicals, power plants and food and beverage as applications, and bonded tanks in particular.
Technical specifications
Data from Tokyo Keiso technical guidance TG-L1021-E02 (FW9000NN series).
| Parameter | Specification |
|---|---|
| Manufacturer / model | Tokyo Keiso FW9000NN series servo balance-type level gauge |
| Level detection | Digitally controlled balancing servo with displacer, measuring wire and wire drum |
| Level accuracy | 0.4 mm (refer to factory for detail); resolution 0.025 mm |
| Interface / density | Interface (density difference 0.2 g/cm3) about 2.7 mm; density 0.005 g/cm3 |
| Measuring range codes | 0 to 5, 10, 15, 18, 25, 30, 40, 60 m (small or large drum up to 30 m; large drum only for 40 m and 60 m) |
| Wire drum | 400 mm/r (small) or 800 mm/r (large) |
| Displacer | Diameter 140, 110, 90, 70, 50 or 30 mm; mass 250 g standard; SUS304, SUS316, SUS316L, MA (Hastelloy equivalent), PTFE |
| Measuring wire | SUS316 0.2 mm standard; options MA 0.3 mm, FEP-covered 0.6 mm stranded |
| Liquid / ambient temperature | Liquid -200 to +300 °C; ambient -40 °C (-20 to +55 °C for TIIS) |
| Operating pressure | Atmospheric, 0 to 1, 0 to 2, 0 to 3 MPa (model codes 1 to 4) |
| Process connection | Flange 3, 4, 5, 6 in or special; JIS 5K to 30K, ANSI 150/300, JPI 150/300 |
| Construction | Weatherproof (NNW) or flameproof Ex d IIC T6 (NNE, TIIS certificate TC14583); IP66/67 |
| Functional safety | SIL2 (IEC 61508) |
| Power supply | 100 to 240 V AC, 50/60 Hz; maximum 25 VA |
| Outputs | 2 contact outputs; 4-20 mA x 2 (level and temperature, 0.5% F.S.); HART Ver.7 on one channel; serial data output |
| Inputs | Pt100 spot and average temperature sensors (-200 to +320 °C); one 4-20 mA signal |
| Alarms | 2 level or temperature alarm points; up to 6 with DIR110NN tank-side indicator |
Design points for tank gauging
The FW9000NN keeps the dimensions and materials of the FW-9000 so it can replace an existing gauge and fit existing Tokyo Keiso transmitters and tank monitoring systems. Noise resistance and lightning protection were improved for bonded tanks, with an option for protection from direct lightning, and the electronics sit in a compartment separate from the drum chamber. Parameters can be set through four magnet sensors at the indicator window without opening the housing, and the power supply covers 100 to 240 V AC.
The displacer horizontal movement per metre of level change is tabulated for each drum size and displacer guide, and stand-pipe guiding is standard. Non-guided or guide-wire installations give no specified accuracy and need factory consultation.
What to confirm before ordering
- Tank height and measuring-range code, with drum size and displacer diameter and material for the liquid.
- Operating pressure class and flange size and rating.
- Weatherproof or flameproof construction for the area classification.
- Whether density, interface, multi-point temperature or contact outputs are needed.
Related Tokyo Keiso products: Tokyo Keiso FM4000 MAG GAUGE Magnetic Metal Tube Level Gauge, Tokyo Keiso TGF7200 Micro Pulse Guided Radar Level Meter and Tokyo Keiso TLR7500 80 GHz Microwave Level Meter.
Documents and quotation
The Tokyo Keiso FW9000NN catalogue is attached to this page as a PDF with the model code, electronics specification and communication functions. Send us the tank data, liquid, pressure, approvals and outputs needed and we will prepare a quotation. Seven Star LLC is an independent supplier in Muscat; price and lead time are confirmed per RFQ. Related range: level instrumentation and the Rosemount 5900S radar level gauge.
Datasheets & Documents
- Catalog Tokyo Keiso FW9000NN Series Servo Balance-type Level Gauge catalogue (TG-L1021-E02) Download
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About brand
Tokyo Keiso is a Japanese manufacturer of flow and level instruments, founded in Tokyo in 1954 as Japan's first maker of variable-area flowmeters. It now builds ultrasonic, Coriolis, electromagnetic and variable-area flowmeters plus level gauges, and set up a production subsidiary in Korea in 2012 for non-contact ultrasonic flowmeters.
Seven Star LLC is an independent supplier in Muscat. We list Tokyo Keiso models from the maker's published technical documents for water, oil and gas, power and chemical plants in Oman and the GCC.
Tokyo Keiso company profile
| Founded | 1954, Tokyo, Japan |
|---|---|
| First products | Variable-area flowmeters, a first for a Japanese manufacturer |
| Headquarters | Tokyo, Japan |
| Leadership | Ryoichi Sugi, President |
| Product families | SONICMAX inline and clamp-on ultrasonic flowmeters (UL3400, UL6300, UL350), MASSMAX Coriolis mass flowmeters, electromagnetic and variable-area flowmeters, float and magnetic level gauges |
Milestones
- 1954: Tokyo Keiso is founded as Japan's first variable-area flowmeter maker.
- 2012: TK Flow Engineering is set up in Korea for ultrasonic flowmeter production.
Tokyo Keiso product series
Ultrasonic flowmeters include the UL350 and SONICMAX UL6300 V2 clamp-on meters and the SONICMAX UL3400 three-beam inline meter. Other flowmeters include the MASSMAX 2400R Coriolis mass flowmeter, the VFM4200 SWIRLMAX vortex meter, the MAGMAX EGM2100C compact electromagnetic flowmeter, the TH series thermal gas flowmeters and the VC series V-Cone differential pressure flowmeter.
Level instruments include the TLR7500 80 GHz microwave level meter, the TGF7200 guided radar, the FM4000 MAG GAUGE magnetic metal tube level gauge and the FW-9000NN servo balance tank gauge for storage tanks.
Where Tokyo Keiso instruments are used
Water and wastewater networks, chemical and petrochemical plants, oil and gas facilities, power stations and tank terminals, with outputs such as 4-20 mA, pulse and digital communication for connection to control systems.
Tokyo Keiso products we list
Ordering Tokyo Keiso instruments: what we need
Send the fluid, line size, flow or level range, pressure and temperature, process connection and materials, output signals and any hazardous-area option. Where a catalogue is older or an option is still in preparation, we say so on the product page.
Facts checked against Tokyo Keiso company profiles and a 2022 interview with its president, October 2026.
Browse Tokyo Keiso products by category: Flowmeters, Level Instrumentation.
FAQ
Questions about the Tokyo Keiso FW-9000NN Servo Balance Tank Level Gauge
Answers from our engineering team on installation, compatibility and integration.
01How does a servo balance level gauge work?
A displacer on a wire is held at the liquid surface by a servo motor; the drum rotation gives the level.
02What resolution does it have?
The catalogue states a level resolution of 0.025 mm and an accuracy of 0.4 mm under reference conditions.
03Can it measure density or interface?
Yes. Interface and liquid density measurement are supported, including multi-point density profiling.
04Is it a SIL device?
The catalogue states SIL2 compatibility (IEC 61508) for the self-diagnosis functions.
05Is a flameproof version available?
Yes. The NNE construction is Ex d IIC T6 under TIIS certificate TC14583, and an ATEX-certified version is mentioned.
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