Development of an EX-certified diamond probe for the IRmadillo spectrometer

Keit has developed a novel FTIR spectrometer, uniquely designed for the process/manufacturing environment. Existing competitive systems have proven vulnerable to the vibrations and shocks common to the process environment. Keit's IRmadillo spectrometer has no moving parts and has proven very reliable in process environments. The IRmadillo measures the concentrations of different components of process liquids - oils, petrochemicals, fine chemicals and biotech for example. The range of chemistries and operating conditions where this capability is needed is very wide. Analyte temperatures can range from -80C to over 300C, pressures range from 1 to 50bar and the analyte pH can be anywhere from -1 to 14. The broader range of operating conditions we can serve, the bigger our market.

A key part of the spectrometer is an optical probe that must be in contact with the liquid analyte. The probe tip is therefore subject to the same physical and chemical conditions of the analyte and must be able to operate and survive for a minimum of 12 months in those conditions. The optical window on our current probe is made of an infrared glass (AMTIR) that is optically good, but unable to withstand pH of greater than 9.5. We have customers who have expressed interest in using our technology but who have chemistry that operates above pH9.5 and for them we have no product. In addition, much of this chemistry happens in potentially explosive atmospheres, so any commercial product needs to pass stringent testing to ensure it is safe for use in such an atmosphere.

The ideal optical material for the mid-infrared and high pH is diamond. This is a standard in the industry. Due to the large size of our probe (required given the fundamental optical design), it is not possible simply to replace the AMTIR optic with an identical diamond. We need to develop a probe who's external elements (in contact with the analyte) are high pH resistant, including diamond, but with the internal mechanics and optics to maximise light throughput and also survive the high pressures and temperatures common in the process chemistry industries.

We have developed and successfully tested an optical concept that incorporates a diamond front window and gives adequate light throughput, but it cannot survive the temperatures (target 150C) and pressures (30bar) nor the explosive atmospheres that it needs to do to be commercially viable. This project will deliver that commercial product.