Abstract: A faceted gem having a polished cone-shaped depression cut into the pavillion, said cone being concentric with the vertical axis of the gemstone, and having an included angle at the cone apex of about 90.degree., and a base diameter equal to about 50% of the girdle diameter. The thus-described polished cone surface reflects light entering the crown, providing a brilliance about equal to that of a correctly-cut gem having full depth of the pavillion. At the same time, the polished internal cone configuration of the pavillion permits a shallow stone to be cut to a maximum girdle diameter, such that the yield in stone size is increased by as much as 50% or more, as compared with the yield obtainable by cutting the pavillion in the conventional manner with correct main angles.

Abstract: An inspection penetrant process and composition therefor in which the penetrant is formulated from a low-solubility liquid, and a solubility accelerator material is added to the formulation to enhance the washability of the penetrant to provide for more rapid removal of background porosity entrapments from test surfaces. The acceleration of solubility is accomplished while the features of slow-solubility and adaptability to recovery and re-cycling procedures are retained.

Abstract: An improved inspection penetrant process employing a dyed liquid nonsurfactant-type penetrant, a remover, and a water rinse, in which the remover consists of a water solution of a nonsurfactant-type solvency accelerator which is selected from the group consisting of dihydroxybenzenes, carbamide and sodium benzoate. The penetrant, which is normally only slightly soluble in water, dissolves more readily in the solvency-accelerated water mixture, with the result that an improved removal of background porosity entrapments of penetrant is obtained, while entrapments of penetrant in crack defects are retained to a high level of entrapment efficiency.

Abstract: Water solutions of certain glycol-ether materials having resistance to extraction by halocarbon extraction solvents are used as solvent removers in an inspection penetrant process. Used solvent remover containing dissolved penetrant material and dyes is bubbled through a column of halocarbon solvent liquid, whereby the oily penetrant and dyes are selectively extracted leaving the glycol-ether/water mixture in a re-usable condition, the concentration of the glycol-ether in water remaining unchanged. Only a few glycol-ether liquids have been found to have the ability to resist extraction from their water solutions, and these substances are specified for use in the process of inspection penetrant usage, recovery and regeneration.

Abstract: A solvent-remover composition and process in which a glycol liquid or water containing an alcohol or glycol-ether accelerator solvent is used as a solvent to remove surface penetrant from test parts in the so-called solvent-remover inspection penetrant process. The remover solvents of the invention provide inhibited solvency for oily water-insoluble dyed penetrant liquids, thus preventing excessively rapid depletion of entrapments in surface cracks. The flaw detection capability of the solvent-remover penetrant process is thereby improved.

Abstract: Water solutions of certain glycol-ether-type materials having negative temperature coefficients of water solubility are used as solvent removers in an inspection penetrant process. The concentration of the glycol-ether-type material in the water is controlled and adjusted by thermostatically controlling the temperature of a solvent remover reservoir containing water and an excess of the glycol-ether-type material. Excess glycol-ether-type material separates by flotation, carrying with it any dissolved penetrant, leaving a bottom layer of purified and re-usable solvent remover solution. The top layer of glycol-ether-type material may be further purified by distillation and reflux condensation to remove contaminants of dye, penetrant, and other foreign materials.

Abstract: A pre-wash stripper composition for use in the water-washable inspection penetrant process consisting of water saturated with dissolved penetrant. The saturated solution cannot dissolve more penetrant, and is therefore incapable of causing depletion of crack entrapments, but when applied to test surfaces by spray, it is capable of removing surface penetrant from test parts to completion of the so-called incubation of washing, and for purposes of recovery of excess surface penetrant for re-use. Test parts which have been pre-washed with the inhibited saturated solution may be finish-washed in clean water with a minimum amount of penetrant carry-over into the finish-wash water.

Abstract: A water-washable inspection penetrant process in which the penetrant is recovered for re-use and the used wash water remains sufficiently pure to be discharged into water disposal systems without causing excessive environmental pollution. A non-surfactant-type low-solubility penetrant which has been applied to test parts is wash-removed, leaving penetrant entrapments in crack defects. The thus-removed penetrant is separated from the wash water by allowing the mixture of water and removed penetrant to stand in a holding tank, whereupon the dispersed penetrant separates from the wash water and floats to the surface where it is collected for re-use. The relatively pure water is drawn from the bottom of the holding tank and is discharged into a water-disposal system.

Abstract: In the water-washable inspection penetrant process, a method and means for recovery of used penetrant in which penetrant-coated test parts are spray-washed in a pre-wash stripper step with water saturated with dissolved penetrant liquid. The saturated-water spray removes excess penetrant by the scrubbing action of spray droplets, but it cannot dissolve and deplete penetrant from crack entrapments. The thus-removed excess penetrant may be separated from the pre-wash water by flotation, and may be recovered for re-use. Following the pre-wash stripper-recovery step, the normal process of washing, drying, and inspection is resumed.

Abstract: An improvement in inspection penetrant processes for the detection of surface defects in test bodies, wherein a water-washable penetrant of the balanced surfactant/synergist type or of the slow-solubility type is inhibited with respect to its solubility in wash water to the point of substantial insolubility except in the presence of mechanical agitation or application of a vigorous spray of wash water, thereby enhancing the flaw entrapment efficiency of penetrant indications. The inhibition or depression of solubility is achieved by any one or a combination of several techniques; (1) raising the temperature of the wash water to above a critical point of solubility inversion, (2) dissolving a solubility-inhibiting solute in the wash water or in the penetrant, and (3) allowing a solubility-producing constituent to evaporate from the penetrant.

Abstract: Process and apparatus for inspection penetrant detection of surface flaws in test parts in which the parts are sequentially process by the steps of (1) applying a dyed liquid penetrant to the test parts, (2) stripper-wash removal of surface penetrant, (3) interim-drying of the test parts, (4) finish-wash depletion of surface micro-entrapments of penetrant, aided by an emulsifier where applicable, (5) drying, and (6) inspection for flaw entrapment indications. The novel step of interim drying acts to alter the interaction of the finish-wash with penetrant entrapments, causing an acceleration of wash removal of the flaw entrapments and a more rapid removal of unwanted entrapments in surface porosities and micro-flaws.

Abstract: Water-washable inspection penetrant compositions which avoid the use of conventional solubilizing detergents. The penetrants comprise an oil vehicle containing a dissolved indicator dye and a fatty acid ingredient dissolved to a concentration within the range of from about 2% to about 25%. The fatty acid ingredient acts as a solubility promoter to permit the penetrant composition to be removed from test surfaces by a spray-wash of water.