Optical flash point detection on an automated open cup flash point detector
View Patent ↗An open cup flash point detector is shown that rapidly increases the temperature of the substance being tested until temperature is close to a theoretical flash point. Thereafter, as temperature is slowly increased, an igniter flame moves in an arc over the upper lip of the test cup while simultaneously a UV sensor senses a wedge-shaped area, also immediately over the upper lip of the test cup. The arc of the igniter flame and the wedge-shaped area do not overlap. By incremental increases in temperature and repeating the arc movement of the igniter flame, the flash point can be detected by the UV sensor.
1. A flash point detector for determining a flash point of a substance being tested using an open cup method, said flash point detector having a source of power and a source of gas, said flash point detector including:
a stand having an upper surface with an opening in said upper surface;
a test cup located in said opening;
a heater connected to said source of power and located below said test cup for heating said test cup and said substance contained therein;
insulation for thermally insulating said test cup and said heater from said stand;
a test cup holder adjacent said test cup for picking up said test cup when hot;
an igniter connected to said gas source for generating an ignitor flame immediately above said test cup; and
an ultraviolet (UV) detector in a collumator located on said upper surface beside said opening;
said ignitor flame periodically swinging in an arc immediately above said test cup;
said collumator restricting a monitoring area of said UV detector to a wedge-shaped area immediately above said test cup;
said arc being adjacent to, but not overlapping, said wedge-shaped area; and
said UV detector detecting when said substance reaches the flash point.
2. The flash point detector as recited in claim 1 wherein said collumator has a chamber where said UV detector is located, and a slot from said chamber to a lens with a beam opening therein, said beam opening allowing the receiving of light from said wedge-shaped area.
3. The flash point detector as recited in claim 2 wherein between said periodically swinging of said igniter flame, a temperature of said substance is incrementally increased.
4. The flash point detector as recited in claim 3 , wherein the flash point detector is configured to:
recording record each temperature where said igniter flame swings immediately above said test cup and record at what temperature said UV detector detects said flash point.
5. A method of operation of an open cup flash point detector to determine a flash point of a substance, said method of operation including:
placing a test cup of said substance in an upper opening of a test stand;
continuously measuring a temperature of said substance in said test cup;
rapidly increasing the temperature of said substance in said test cup until said substance approaches a theoretical flash point;
thereafter, slowly increasing temperature of said substance in said test cup;
periodically swinging an igniter flame in an arc just above said test cup;
monitoring a wedge-shaped area just above said test cup with a UV detector to detect when said substance flashes; and
recording the temperature of said substance when said substance flashes;
said arc and said wedge-shaped area are adjacent and above said test cup, but not overlapping.
6. The method of operation of an open cup flash point detector as recited in claim 5 wherein said monitoring step includes locating said UV detector in a chamber of a collumator connected by a slot to a lens with a beam opening to allow ultraviolet light from said wedge-shaped area to enter said collumator, said wedge-shaped area being just above said test cup.