Method for non-contact cleaning of fiber optic connectors and end faces
A cleaning device ( 100 ) for cleaning fiber optic end faces comprises a dispensing nozzle ( 104 ) configured to discharge a jet column ( 118 ) generated by the Coanda effect with intermittent injection of a cleaning solvent into the jet column ( 118 ). The method comprises impinging the jet column ( 118 ) onto a fiber optic end face ( 120 ) while maintaining a stand-off distance from the end face being cleaned.
1. A method of cleaning an end face of an optical fiber with a cleaning device comprising a nozzle having a nozzle outlet, within which is disposed a needle plug of diminishing cross section in the direction of outward flow through the nozzle and terminating in a pointed tip facing outwardly of the nozzle, the method comprising:
flowing a compressed gas stream through the nozzle over the needle plug and through the nozzle outlet, the needle plug and nozzle outlet being configured to form an emitted gas jet exiting from the nozzle outlet, the emitted gas jet forming a zone of reduced pressure relative to ambient pressure, the zone of reduced pressure surrounding the emitted gas jet;
aligning the nozzle outlet with such end face and positioning the pointed tip of the needle plug from about 0.25 inch to about 0.75 inch (0.64 to 1.91 cm) from such end face;
introducing a liquid solvent upstream of the nozzle outlet into the compressed gas stream, whereby the solvent is atomized in the emitted gas jet, impinging the emitted gas jet containing atomized solvent onto such end face for a cleaning time period; and
discontinuing introduction of the solvent into the compressed gas stream to produce a dry gas jet and impinging the resulting dry gas jet onto such end face for a drying time period to remove solvent by evaporation which is accelerated by the zone of reduced pressure.
2. The method of claim 1 wherein the cleaning time period is from about 0.5 to about 2 seconds and the drying time period is from about 1 to about 4 seconds.
3. The method of claim 1 or claim 2 wherein the liquid solvent has a vapor pressure at 25° C. and one atmosphere pressure of from about 20 to about 30 kPa, a Kauri Butanol value of from about 18 to about 44 and is non-flammable per ASTM D-56 Closed Cup Flash Point test.
4. The method of claim 1 or claim 2 wherein the liquid solvent introduced into the gas jet may comprise
(a) 83 wt % hydrofluoroether comprising: 55 to 90 wt % methyl nonafluoroisobutyl ether, and 10 to 45 wt % methyl nonafluorobutyl ether;
(b) 10 wt % hydrofluoroether comprising: 90 wt % Z-isomer, and 10 wt % E-isomer; and
(c) 7 wt % heptane, the solvent containing less than 10 ppm non-volatile residue and less than 100 ppm moisture.
5. The method of claim 1 or claim 2 wherein the liquid solvent introduced into the gas jet comprises 60 wt % 1,1,1,3,3,3-hexafluoro-2-methoxypropane, 34.9 wt % 1-chloro-2,3,3-trifluoroprop-1-ene, 5.0 wt % acetone, and 0.10 wt % nitromethane, the solvent containing less than 10 ppm non-volatile residue and less than 100 ppm moisture.
6. The method of claim 1 or claim 2 wherein the nozzle outlet comprises a gas outlet and a separate solvent outlet and the needle plug is disposed within the solvent outlet, the method further comprising moving the needle plug between an open position which opens the solvent outlet to dispense solvent into the compressed gas stream and a closed position which stops the dispensing of solvent into the compressed gas stream, and moving the needle plug into the open position to initiate the cleaning time period and moving the needle plug into the closed position to terminate the cleaning time period and initiate the drying time period.
7. The method of claim 1 or claim 2 wherein the compressed gas is selected from the group consisting of air, nitrogen and carbon dioxide.
8. The method of claim 1 or claim 2 wherein the velocity of the emitted gas jet flowing over the needle plug is sufficient to cause a Coandă effect to generate the zone of reduced pressure.