Hot running electronics clear blood sensor

Problem: . The set working temperature is 50 deg C and the process involves the use of some fairly corrosive solvents and tends to deposit waxes. The previously employed technology was based on thermistors, but when these became coated in wax, they responded too slowly to avoid overflows. Solution: Gems Sensors developed an optical sensor, the ELS 1150, to respond more immediately to level changes. It uses an infrared LED and receiver, within a glass droplet deflecting prism, which the company says enables it to excel over dome-type sensors. However, when first trialled, it too tended to become wax coated and malfunctioned. The solution in this case was to move away from the latest technology small and highly efficient transistors and circuitry, opting instead for components with a high enough heat output to prevent wax deposition. Applications: The device measures 35mm long and is suitable for use in pressurised vessels up to 170 bar. Other applications include critical leak detection in chemical storage tanks, environmental protection, automated lubricating oil monitoring, coolant and hydraulic fluid measurement and fire protection systems. Units are capable of switching 18mA, normally open or normally closed, and are currently available with 1/2inch NPT mountings. The operating range is -40 to 100 deg C and operating voltages are either 5VDC or 12VDC. Other mountings will be available in the near future as will a lower- cost version that will be designated ELS 900. TS Gems Sensors Cindy Lane at Gems Sensors