Patent ID: 7025338

Claim:
A direct contact steam injection heater comprising: a heater body having a steam inlet, a flowing stock inlet and a heated stock discharge outlet, the flowing stock inlet and the heated stock discharge outlet being aligned such that the flowing stock flows through the heater body generally in an axial direction; a diffuser tube mounted transverse to the axial direction of stock flow through the heater body, the diffuser tube having a cylindrical outer wall having a first emitter section and a second emitter section, each emitter section having a plurality of steam diffusion holes, the diffuser tube being arranged to receive the flow of steam and discharge the steam through the diffusion holes into the flowing stock; an adjustably positionable steam-plug cover positioned within the diffuser tube, the steam-plug cover having a cylindrical outer wall defining an open interior that receives a flow of steam, the outer wall having a first open slot and a second open slot that enables steam to flow out of the open interior; and a first resilient seal member surrounding the first open slot formed in the steam-plug cover and a second resilient seal member surrounding the second open slot, wherein the first and second seal members contact an inner wall of the diffuser tube to provide a seal between the inner wall of the diffuser tube and the steam-plug cover surrounding the open slot, wherein the steam plug cover is adjustably positionable between a fully open position where a maximum number of steam diffusion holes are aligned with the open slots and a fully closed position in which no steam diffuser holes are aligned with the open slots, wherein the entire first emitter section is positioned between the first seal member and the second seal member and the entire second emitter section is positioned between the first seal member and the second seal member when the steam plug cover is in the fully closed position.