Abstract: A method and apparatus entrain particles in a flow of blast fluid from a flow of transport fluid with particles entrained therein, in which an effectual amount of the transport fluid is vented or extracted prior to the entrainment of the particles in the flow of blast fluid.

Abstract: A method of comminuting the size of particles of frangible blast media from each particle's respective initial size to a size smaller than a desired maximum size includes directing a flow of entrained particles toward a gap, at a first location splitting the flow into at least a first and second flow, the particles are entrained in the first flow, the first flow travels through the gap and substantially no particles are entrained in the second flow, and rejoining the second flow with the first flow at a second location downstream of and proximal to the gap.

Abstract: An actuator is configured to couple with a controlled member and includes first and second pistons disposed in respective internal chambers. The first piston may be moveable between first and second positions. The second piston may be moveable between third and fourth positions. The second piston may be configured not to engage the first piston when the second piston is disposed at the third position. The second piston may be configured to move the first piston to the second position as the second piston moves from the third position to the fourth position. A resilient member may be disposed to resiliently urge the second piston toward the fourth position.

Abstract: A method of comminuting the size of particles of frangible blast media from each particle's respective initial size to a size smaller than a desired maximum size includes directing a flow of entrained particles toward a gap, at a first location splitting the flow into at least a first and second flow, the particles are entrained in the first flow, the first flow travels through the gap and substantially no particles are entrained in the second flow, and rejoining the second flow with the first flow at a second location downstream of and proximal to the gap.

Abstract: A comminutor reduces the size of particles of frangible blast media from each particle's respective initial size to a size smaller than a desired maximum size. The frangible blast media may be entrained in a flow of transport gas. The comminutor includes an inlet and an outlet, both in fluid communication with an internal flow passageway. The internal flow passageway includes a first intermediate passageway which comprise the gap defined by two rotating rollers and a second intermediate passageway which includes an inlet disposed proximal the gap, extending in an upstream direction therefrom.

Abstract: An actuator is configured to couple with a controlled member and includes first and second pistons disposed in respective internal chambers. The first piston may be moveable between first and second positions. The second piston may be moveable between third and fourth positions. The second piston may be configured not to engage the first piston when the second piston is disposed at the third position. The second piston may be configured to move the first piston to the second position as the second piston moves from the third position to the fourth position. A resilient member may be disposed to resiliently urge the second piston toward the fourth position.

Abstract: A particle blast apparatus or system entrains blast media particles from a particle source into a transport fluid which already has blast media particles entrained therein. The system may have, prior thereto, entrained blast media particles into the transport fluid which at that time did not already have blast media particles entrained therein. The particle types may be dissimilar, such as dry ice particles and abrasive media particles.

Abstract: An apparatus is described which introduces cryogenic particles received from a source of particles, having a first pressure, into a moving transport fluid, having a second pressure, for ultimate delivery to a workpiece or target as particles entrained in a transport fluid flow which seals between the source of particles and the transport fluid flow.

Abstract: A particle blast apparatus includes a metering portion, a comminutor and a feeding portion. The metering portion and comminutor may each be configured to provide uniformity in the discharge of particles. The metering portion controls the particle feed rate, and may include a rotor, which may have V or chevron shaped pockets. The comminutor includes at least one roller which may be moved between and including a position at which the gap of the comminutor is at maximum and a position at which the gap is at minimum. The metering portion may discharge direction into the feeding portion without a comminutor being present. The comminutor may receive particles directly from a source of blast media without a metering portion being present.

Abstract: An apparatus is described which introduces cryogenic particles received from a source of particles, having a first pressure, into a moving transport fluid, having a second pressure, for ultimate delivery to a workpiece or target as particles entrained in a transport fluid flow which seals between the source of particles and the transport fluid flow.

Abstract: An apparatus is described which introduces cryogenic particles received from a source of particles, having a first pressure, into a moving transport fluid, having a second pressure, for ultimate delivery to a workpiece or target as particles entrained in a transport fluid flow which seals between the source of particles and the transport fluid flow.

Abstract: A comminutor reduces the size of particles of frangible blast media from each particle's respective initial size to a size smaller than a desired maximum size. The frangible blast media may be entrained in a flow of transport gas. The comminutor includes an inlet and an outlet, both in fluid communication with an internal flow passageway. The internal flow passageway includes a first intermediate passageway which comprise the gap defined by two rotating rollers and a second intermediate passageway which includes an inlet disposed proximal the gap, extending in an upstream direction therefrom.

Abstract: An apparatus is described which introduces cryogenic particles received from a source of particles, having a first pressure, into a moving transport fluid, having a second pressure, for ultimate delivery to a workpiece or target as particles entrained in a transport fluid flow which seals between the source of particles and the transport fluid flow.

Abstract: Liquid carbon dioxide is transformed into solid snow and compressed into strands. A shroud defines an insulating plenum/volume surrounding a forming chamber, which reduces heat transfer to the forming chamber. A faction of gas phase flow resulting from the process fills the insulating plenum/volume, reducing heat transfer further.

Abstract: A particle blast system includes a feeder assembly having a rotor with a plurality of pockets formed in the peripheral surface. The transport gas flowpath includes the pockets, such that substantially all transport gas flows through the pockets. The seal adjacent the peripheral surface is actuated by the transport gas pressure to urge its sealing surface against the rotor's peripheral surface. At start up, there is no substantial pressure between the seal and the rotor, reducing start up torque requirements.

Abstract: A particle blast system includes a feeder assembly having a rotor with a plurality of pockets formed in the peripheral surface. The transport gas flowpath includes the pockets, such that substantially all transport gas flows through the pockets. The seal adjacent the peripheral surface is actuated by the transport gas pressure to urge its sealing surface against the rotor's peripheral surface. At start up, there is no substantial pressure between the seal and the rotor, reducing start up torque requirements.

Abstract: A particle blast system includes a feeder assembly having a rotor with a plurality of pockets formed in the peripheral surface. The transport gas flowpath includes the pockets, such that substantially all transport gas flows through the pockets. The seal adjacent the peripheral surface is actuated by the transport gas pressure to urge its sealing surface against the rotor's peripheral surface. At start up, there is no substantial pressure between the seal and the rotor, reducing start up torque requirements.