Abstract: A method and apparatus for detecting the presence of a gaseous substance within a space bounded by an enclosure utilizes the fact that sound is not transmitted through a vacuum and is transmitted through the material of the enclosure. A sonic wave transmitter and a sonic wave receiver are engaged with the material of the enclosure and separated by the space. Using the calculated arrival times and/or amplitudes for the soundwave portions through the space and through the material of the enclosure, it can be determined whether a soundwave portion has passed through the space and thus a leakage of gaseous substance into the space above a threshold amount has taken place.

Abstract: A method and apparatus for deslagging boilers and the like while steaming, wherein a quenching-type stream of water is first applied to the outer surface of the hot slag to induce the formation of fissures by embrittlement and contraction of the slag and thereafter while the fissures are still present the fissured surface of the slag is impacted by a high velocity pulsed jet which drives water into the fissures, whereby dislodging of the slag is aided by the expansive force of water which vaporizes in the fissures. A generally conventional blower is illustrated, equipped with dual liquid supply and projecting means, and pulsing mechanism for interrupting the flow of blowing medium to one of the projecting means, to create the pulsed jet.

Abstract: A sootblower of the long retracting variety including a drive system which simultaneously rotates the lance tube as it is inserted and withdrawn from the boiler. A variable speed drive is employed to modulate the rotational speed of the lance tube in accordance with the projected distance of the lance tube such that the lance tube is driven faster at intermediate lance tube projected distances thereby optimizing the cycle time of the sootblower. The modulated rotational speed of the lance tube is maintained at all projected distances below the critical speed which varies as a function of projected distance and the sootblower type. By driving the lance tube at certain projected distances at a rotational speed above the critical speed for other projected distances, the translational speed is increased and cycle time reductions are realized as compared with the prior art wherein the lance tube is driven at a constant speed below the minimum critical speed.

Abstract: A method and apparatus for removing adherent deposits from high temperature surfaces such as the fire sides of the tubes of boilers while steaming is disclosed as employing a sootblower to project a moving pulsed jet of liquid against the deposits. The peak impact pressure of the jet is increased by pulsing means disclosed as of a fluidic or rotary type.

Abstract: Roller-type supporting means is disclosed herein for the lance tube of a long retracting sootblower. An assembly of four rollers is mounted in a cradle structure rockable about an axis transverse to the beam of the sootblower and also swingable about a vertical axis radial to the lance tube axis. The sides of the cradle structure are defined by rocker arms capable of limited independent rocking movement. The rollers are laterally and longitudinally spaced from each other and underengage and support the lance tube. The points of engagement between the rollers and the lance tube lie approximately in a common plane which also includes said transverse axis.

Abstract: Roller supporting means for the lance tube of a long travel retracting soot blower includes a pair of castering-type roller assemblies having their castering axes non-vertical. Each roller assembly is counterweighted to such extent as to substantially statically balance the assembly about its castering axis.