Abstract: A method of cleaning a solid surface which is particularly effective for a surface having a complicated structure including slots and holes comprises immersing the solid surface in a cleaning slurry comprising a cleaning liquid and abrasive particles which are soluble in the cleaning liquid, the cleaning liquid comprising a saturated solution so as to greatly reduce the dissolution of the abrasive particles in the cleaning liquid.

Abstract: A method of cleaning a solid surface which is particularly effective for a surface having a complicated structure including slots and holes comprises immersing the solid surface in a cleaning slurry comprising a cleaning liquid and abrasive particles which are soluble in the cleaning liquid, the cleaning liquid comprising a saturated solution so as to greatly reduce the dissolution of the abrasive particles in the cleaning liquid.

Abstract: Blast cleaning with at least two types of abrasives employing a blasting apparatus having at least a first and a second closed blasting pot connected to a conveying line and the conveying line and each blasting pot are connected to a source of compressed gas by a differential pressure metering system. The differential pressure metering system provides a differential pressure between each blasting pot and the conveying line enabling blasting media in each pot to pass from each pot through a variable size orifice to the conveying line. Each blasting pot can be operated independently of each other enabling varying proportions of different types of blast media to be released in the conveying line and blasted from a nozzle to clean a solid surface.

Abstract: A method and apparatus for effecting the continuous reliable supply of sodium bicarbonate particles to a blasting nozzle employing pressured air or water for conveying such particles into contact with a surface to be cleaned. The apparatus includes a hopper at atmospheric pressure and a removable orifice through which the abrasive particles are directed from the hopper to an open ended pipe. One end of the pipe is connected to a media conveying line and a venturi passage provided in a blast nozzle whereby a pressurized fluid passing through the venturi passage creates a suction force in the conveying line and the pipe such that atmospheric air and abrasive particles are drawn from the air pipe to the blast nozzle. The amount of air flow permitted through the pipe can be adjusted by a valve to control the vacuum within the conveying line and along with the particle feeding orifice controls the concentration of abrasive particles in the air stream directed to the nozzle.

Abstract: An improved slurry blasting process is disclosed wherein a liquid carrier medium such as water contains a dispersed water-soluble particulate abrasive to enhance blast cleaning efficiency and wherein the liquid carrier comprises a saturated solution such as the dissolved particulate abrasive so as to minimize the dissolution of the particulate abrasive therein. Slurry blasting at relatively low pressures below 500 psi and at room temperature provides effective and cost efficient cleaning of substrates. The slurry can be recovered and continuously reused. A recrystallization agent can be added to the slurry to increase abrasive particulate growth in the saturated solution.

Abstract: To reduce dust and improve the productivity of wet blasting, a blast nozzle and a method of using same are provided for directing a stream of abrasive particles entrained in compressed air to a targeted surface and for injecting a pressurized water stream into the stream of abrasive particles at a point downstream of the orifice of the blast nozzle and in the expansion portion of the nozzle. At the injection point, the velocity of the entrained abrasive particles is substantially equivalent to the velocity of the injected water stream.

Abstract: A media control valve used to dispense and meter an amount of abrasive media from a supply pot to a compressed air line for blast cleaning comprises a vertical discharge passage and an air flow tube communicating with the vertical discharge passage, a media control sleeve placed in an inclined bore in the valve body and disposed between the vertical discharge passage and air flow tube, the media control sleeve comprising a plurality of spaced orifices which allow communication between the vertical discharge passage and the air flow tube, the media control sleeve being rotatable in place within the valve body bore so as to present a different orifice in communication with the discharge passage.

Abstract: Improvements to blast cleaning apparatus, and particularly to a media control device which contains a fixed orifice placed between the abrasive supply pot and a media outlet to the compressed air line to meter the media flow into the air line and means to maintain a positive pressure differential between the supply pot and the air line further includes a means to equalize the pressure between the air line and a media passage immediately below the orifice. An additional improvement comprises adding a flow straightening device upstream of a bend in the air line so as to reduce back-mixing in the bend and consequently the turbulence of air downstream of the bend and across the media outlet into the air line.

Abstract: An improved wet blasting process is disclosed wherein the liquid carrier medium contains a dispersed particulate abrasive to enhance the blast cleaning efficiency and wherein the particulate abrasive is soluble in the carrier liquid. To minimize dissolution of the soluble particulate abrasive, the liquid carrier comprises a saturated solution such as the dissolved particulate abrasive in the liquid.

Abstract: A conventional blasting apparatus is modified to provide a separate source of line air to a blast pot through a pressure regulator to provide a greater pressure in the blast pot than is provided to the conveying hose. This differential pressure is maintained by an orifice having a predetermined area situated between the blast pot and the conveying hose. This orifice provides an exit for the blast medium and a relatively small quantity of air from the blast pot to the conveying hose, and ultimately to the nozzle and finally the workpiece. The differential air pressure, typically operating between 1.0 and 15.0 psi with an orifice having an appropriate area, yields acceptable media flow rates in a controlled manner.

Abstract: Blasting media for removing coatings from sensitive metal and composite surfaces, and a process useful therewith, wherein the blasting media comprise mixtures of water-soluble crystalline sodium bicarbonate particles having average particle sizes of from 100-500 microns.

Abstract: Conventional industrial pressure blasting apparatus is modified to allow a controlled pressure on the blast pot that is greater than the pressure on the line where less aggressive abrasive media and air are mixed for conveying the mixture to the nozzle and then to the workpiece. A media control device, with a fixed but readily variable area, is placed between the blast pot and the media/air mixing line to meter the media flow and maintain a positive pressure differential between the blast pot and the line. Adjusting the pressure differential allows control of the weight ratio of the media-to-air flow to between about 0.05 to 0.25.

Abstract: Conventional industrial pressure blasting apparatus is modified to allow a controlled pressure on the blast pot that is greater than the pressure on the line where the media and air are mixed for conveying the mixture to the nozzle and then to the workpiece. A media control device, with a fixed but readily variable area, is placed between the blast pot and the media/air mixing line to meter the media flow and maintain the pressure differential between the blast pot and the line. This allows control of the media flow when low flow rates, below about 10 pounds per minute, are required.