A surface treatment method is provided that is capable of raising the slidability of a ceramic surface at low cost using a comparatively simple method. Dimples are formed on a surface of a treatment region, this being a portion of a ceramic surface where surface treatment is to be performed, by ejecting substantially spherical ejection particles having a median diameter of from 1 m to 20 m, together with compressed gas at an ejection pressure of from 0.01 MPa to 0.7 MPa, so as to achieve a value of a fastest decay autocorrelation length of not less than 10. The dimples are formed so as to have a plan view profile with a ratio between a horizontal Feret diameter and a vertical Feret diameter of from 0.7 to 1.43. Thereby a ceramic surface with improved slidability can be obtained regardless of use or non-use of a lubricant.

A pop-up valve or valve assembly operable to manage backflow, the assembly configured with a stem or stem portion. The assembly includes a valve sleeve disposed on the stem. The valve sleeve is configured to engage the stem. A stem outside diameter is smaller than an inside diameter of the valve sleeve, such that the sleeve is able to move freely on the stem and also provide a restricted passage for airflow.

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 particles directly 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.

Apparatus for generating a pulsating pressurized fluid jet are disclosed. One disclosed example includes a line system having at least one nozzle with at least one nozzle orifice from which a pulsating fluid jet of pressurized fluid emerges, and a chamber having a pressure wave generating device to generate fluid pressure waves, where the chamber is in fluid communication with the line system through an outlet opening for the generated fluid pressure waves. The disclosed example also includes a setting device for controlling the amplitude of the fluid pressure waves in the line system upstream of the at least one nozzle orifice where the setting device sets a quotient of a path length of the fluid pressure waves between the outlet opening and the at least one nozzle orifice, and the wavelength of the fluid pressure waves in the line system.

An abrasive jet cutting system may include a differential pressure measurement apparatus configured to measure a differential pressure between points in an abrasive supply system. The differential pressure may be used to determine one or more conditions of the jet and the abrasive delivery. The measured differential pressure may be used in a feedback control system, feed forward control system, and/or an alarm or safety system.

An abrasive jet cutting system may include a differential pressure measurement apparatus configured to measure a differential pressure between points in an abrasive supply system. The differential pressure may be used to determine one or more conditions of the jet and the abrasive delivery. The measured differential pressure may be used in a feedback control system, feed forward control system, and/or an alarm or safety system.

A grit blasting arrangement for cleaning chemical reactor tubes includes means for ensuring the grit blast nozzle is coaxial with the longitudinal axis of the tube to be cleaned. The grit blasting device for cleaning tubes spaced apart by upper and lower tubesheets. The grit blasting device includes a grit blast nozzle mounted on a positioning frame and projecting outwardly with an outlet directed into a tube opening during a cleaning operation. The device includes a plurality of stop pins mounted on the positioning frame designed to abut a tubesheet and to define an imaginary plane coplanar with the tubesheet. The plurality of stop pins when abutting the tubesheet prevent the outlet of the nozzle from extending into the tube causing a venturi effect.

An abrasive jet cutting system may include a differential pressure measurement apparatus configured to measure a differential pressure between points in an abrasive supply system. The differential pressure may be used to determine one or more conditions of the jet and the abrasive delivery. The measured differential pressure may be used in a feedback control system, feed forward control system, and/or an alarm or safety system.

A device for continuously feeding media from an unpressurised container to a pressurised chamber without depressurising the chamber is described. The device comprises a cylinder having two chambers defined by a top wall, and bottom wall, and a dividing wall intermediate the top and the base walls. The top wall comprises an inlet aperture for inlet of media and a pressure equalisation aperture. The dividing wall comprises an inlet aperture for receipt of media from the first chamber and a pressure equalisation aperture in fluid communication with a first pressure equalisation conduit that extends from the second aperture to a top of the first chamber. The bottom wall comprises an inlet aperture for supply of media to the blasting machine and a pressure equalisation aperture in fluid communication with a second pressure equalisation conduit that extends from the pressure equalisation aperture to a top of the second chamber. Closure means associated with the inlet and pressure equalisation apertures in the top, dividing and bottom walls, are provided, each closure means being adapted to open and close the apertures in sequence in which the pressure equalisation aperture is opened prior to the inlet aperture aperture.

Reduced noise abrasive blasting assemblies and systems are described. The new assemblies and systems are comprised of standard blast hose, accelerator hose, couplings and nozzle. The improved abrasive blasting system maintains abrasive particle velocity while decreasing the exit gas velocity and consequently decreasing sound production. This is accomplished through an acceleration section with reduced inner diameter and sufficient length to provide the necessary abrasive particle velocity. The new system maintains the productivity and efficiency of conventional abrasive blasting systems but with greatly reduced acoustic noise production and reduces operator fatigue due to the lower weight of the carried portion of the system.