Alliedsignal Inc.

3m Innovative Properties Company

Joel E Rodgers

Rajat S Basu

Ellen L Swan

Michael Van Der Puy

David Nalewajek

David Paul Wilson

Peter B Logsdon

Harry F Osterman

Daniel Franklin Harnish

Michael J Ruckriegel

Hepburn Ingham

Thomas W Godlewski

Alton D Romig

Ambrose J Schmitz

Gary J Zyhowski

Algar Saulic

A non-aqueous cleaning process uses an organic solvent for removing soil or surface contamination from contaminated articles such as printed circuit boards which are cleaned by immersion into a sump compartment of a cleaning tank containing the organic cleaning solvent. The organic solvent is preferably a hydrocarbon solvent. The cleaned articles, now coated with the organic cleaning solvent, are then disposed in a rinsing sump containing a fluorocarbon based rinsing solvent having an affinity for the organic cleaning solvent. The organic solvent is thus removed from the articles which are then dried without waste water as in a conventional solvent vapor degreasing solvent process.

Multiple solvent cleaning system

A solvent control arrangement for stripping liquid solvent from parts being degreased/defluxed in a degreaser or defluxer by intimate contact with liquid solvent or a vapor phase thereof is disclosed. The solvent control arrangement comprises a tank or box having an open end extending downwardly into the vapor zone in an exit area of the degreaser/defluxer to define a flash drying chamber above and in communication with the vapor zone. The solvent covered parts are directed into the flash drying chamber from the vapor zone where heat is applied to heat the air in the flash drying chamber to a temperature above the solvent boiling point to thereby evaporate liquid solvent on the parts. The parts are then returned from the chamber into the vapor zone where they ultimately exit the degreaser/defluxer from the exit end. Optionally, condensing coils may be disposed in the chamber at the vapor line to condense solvent in the chamber and prevent the solvent vapor zone from encroaching within the chamber. The amount of solvent within the chamber may be further controlled through an outlet duct arrangement directing solvent laden air from the chamber through dehumidifying coils, molecular sieves, carbon absorption filters or like solvent stripping mechanisms.

Flash drying treatment of solvent from workpieces

A vapor degreasing open topped defluxer is disclosed in which cleaning solvent vapors are generated by boiling a liquid solvent in an open topped tank with the parts to be cleaned inserted therein through the open top. The open topped tank is formed from plural upright sidewalls connected to a bottom wall. Heating elements disposed in the tank bottom vaporize the solvent such that the generated heated solvent vapors rise above the liquid solvent to contact the parts to be cleaned and dissolve the grease on the parts. A condenser coil supported within the tank above the liquid solvent condenses the solvent vapors and defines an upper limit or vapor line of the solvent vapor zone located above the liquid solvent and below uppermost edges of the upright sidewalls. The light rising solvent vapors have a natural tendency to rise upwardly out of the tank by following a convection flow path generally along the inner surfaces of the sidewalls and upwardly past the uppermost edges thereof. To control the expulsion of vapors into the surrounding ambient environment, the uppermost edges are formed with a downwardly and inwardly turned lip coextensive with the length and width of the tank. The lip intercepts the convection flow path to deflect the light rising vapors both inwardly and downwardly back towards the condenser coil. The invention also discloses a removably attachable tank extension which may be attached to the existing tank sidewalls to increase the freeboard height of the tank. The uppermost edges of both the existing tank sidewalls and the tank extension sidewalls may be formed with a downwardly and inwardly turned lip to intercept the convection flow path. The tank extension may be pinned and thereby secured to the existing tank sidewalls at various elevations to optimize the freeboard height as a function of the boiling temperature of the solvent being used.

Open top defluxer with improved solvent vapor recovery

A solvent vapor control apparatus used in conjunction with a degreaser or defluxer into which articles to be degreaser or defluxed are conveyed into intimate contact with liquid solvent and/or a vapor phase thereof is disclosed. The vapor control apparatus includes a housing having a conveyor flow path with an inlet opening in communication with solvent vapor in the degreaser/defluxer and an outlet in communication with ambient air. The inlet is preferably disposed elevationally above the solvent vapor zone to impede outflux of solvent vapor. A baffle defining the uppermost extent of the conveyor flow path establishes a low point in the path disposed elevationally below adjacent upstream and downstream sections of the path. The low point is provided with chilled air which condenses solvent vapor as the articles are forced to enter the chilled air section. Solvent condensate is recovered and a separate drain is provided to collect water condensate from ambient air entering the chilled air section through the flow path outlet. The solvent vapor control arrangement may be provided as retrofit additions to one or both entrance and exit ends of the degreaser/defluxer or may be constructed as integral components of new or existing degreasing/defluxing equipment. A method of recovering solvent vapor is also disclosed.

Cold air lock vapor seal for process solvent vapor recovery and control

Azeotrope-like compositions comprising 1,1-dichloro-1-fluoroethane, dichlorotrifluoroethane, and nitromethane are stable and have utility as solvents in a variety of industrial cleaning applications including cold cleaning and defluxing of printed circuit boards.

Azeotrope-like compositions of 1,1-dichloro-1-fluoroethane,

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Convent Station, NJ, United States of America

Joel E Rodgers