Our History

1925 Dr. Jiro Tsuji, founder of Riken Keiki, develops the Interferometer (world’s first combustible gas monitor) based on lightwave interference.

1927 Dr. Oliver W. Johnson invented the first catalytic combustion gas sensor leading to the first combustible gas Indicator.

1939 Riken Keiki Fine Instrument Co., Ltd. is established and the Interferometer gas monitor is in full production.

1966 WEATHERALL MINING EQUIPMENT AND INSTRUMENTS LIMITED was formed by founder Mr Helmut Weatherall who supplied Riken Keiki Model 18 to the British Coal Board for use in all UK coal mines.

1959 Riken develops combustible gas monitors based on catalytic sensors.

1969 Riken builds the first combination combustible and oxygen portable gas monitor with alarm model GX-3.

1970 Together with Riken Mr WEATHERALL develops the Model 18 to measure ANAESTHETIC GASES in conjunction with Dr John F Nunn, an Anaesthetist at the London Hospital. The results of his research were published in 1970 in the British Journal of Anaesthesia; helping validate the principle of interference refractometry as a technique suitable for measuring anaesthetic gases. Following this development, Riken produced the Model 18 for Halothane.
The tremendous worldwide success of this instrument in Riken’s product line up, can be directly attributed to Mr Weatherall.

1971 Riken begins OEM sales to the USA with portable and fixed gas monitors.

1978 Riken introduces the world’s first 3 gas monitor with alarm, model 1641.

1980 Models OX-80, CO-80, and HS-80 become the first pocket size monitors from Riken.

1981 Mr Weatherall retires, and Mr Roger Worthington takes over the import and distribution of Riken Keiki gas detection products in the newly formed company WEATHERALL EQUIPMENT & INSTRUMENTS LIMITED

1982 Riken introduces the world’s first 3 gas, belt worn monitor, the GX-82.

1983 Riken introduces RI-411, portable IR unit for CO2.

1984 Riken offers the RI-413, portable IR unit for Freons.

1986 Riken presents the GX-86, world’s first 4 gas, belt worn portable monitor.

1991 Riken introduces the 4 gas monitor GX-91B. Also, the OX-62B single gas O2 with extender cable, and the SC-90 super toxic portable.

1994 In a joint venture, RKI Instruments, Inc. becomes Riken Keiki’s North American Partner. Also unveiled is the GX-94 four gas portable with data logging and auto calibration.

1995 RKI and Riken together develop and introduce the first 6 gas portable monitor, the EAGLE.

1997 Riken offers the GasWatch, the first wrist worn multi- gas monitor.

1996 Weatherall wins the contract to supply 700+ detection points at Phase 3 plant at the NEC Semiconductor Fab in Scotland

1999 Riken introduces the GD-K77D smart transmitter with greatly simplified calibration and maintenance.

2000 RKI develops and begins shipping the Diffusion Eagle. 550,000 portable and fixed gas monitors sold to date by Riken Keiki.

2001 Riken introduces the GX-2001, worlds smallest 4 gas monitor.

2003 Riken introduces the GX-2003, five-sensor sample drawing personal monitor, measures % LEL and % volume Methane.

2005 RKI purchases a new building for the corporate headquarters located at 33248 Central Ave, Union City, California.

2008 WEATHERALL achieve ISO 9001 certification for our Quality Management System for “The distribution, repair and servicing of portable and fixed gas detection equipment”.

2009 Riken introduces the GX-2009. The worlds new smallest 4 gas monitor.

2012 Riken introduces the GX-2012. Five-sensor sample drawing monitor.

2015 WEATHERALL supply and install a new multi-point fixed gas detection system at one of GE’s manufacturing plants.

2016 Riken introduce the GX-6000, six gas sample drawing personal monitor with PID & toxic gases.