GB1068375A - Flash point testing or measuring instrument and method - Google Patents

Abstract

1,068,375. Measuring flash points. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N. V. Aug.7, 1964, No. 32358/64. Headings G1D and G1N. An instrument for measuring the flash point of a liquid comprises a flash chamber 1 including a liquid chamber 3 and a vapour chamber 4 situated above it, a spark electrode 5 within the chamber 4, a weir 20 for keeping the liquid in the chamber 3 at a constant level, a thermocouple for measuring the temperature of the liquid, and means including a diaphragm 10 for detecting a flash occurring in the chamber 4, the liquid and oxygen containing gas being heated by passage round a heater 14 and fed to the chamber 3, a separate heater 23 being provided for the vapour chamber 4, the heaters being controlled so that when flashing occurs, the supply to the heaters is switched off. In Fig. 1 the liquid is supplied via a line 12 to a preheater 25 controlled from a controller 26. Air is fed in at 13 and the temperature measured by a thermocouple 27. The controller 26 is set at 28 to maintain a desired temperature difference between the thermocouples 27 and 21. The air and liquid are then heated further by passage spiral fashion around the heater 14, and are fed to the chamber 3. A spark is generated at the electrode 5 every ten seconds as determined by a motor (not shown) with a wiper contacting H. T. supply during rotation. When flashing occurs the diaphragm 10 closes a switch 11 serving to actuate a relay cutting off the supply to the heater 23 and reducing that to the heater 14. The heater 14 is fed from a potentiometer wiper driven by a suitable motor so that the power fed to the heater 14 gradually increases. When flashing occurs the relay causes the motor to reverse its direction of rotation. The temperature as indicated by the thermocouple 21 may be fed to a recorder 22.