Rotary dryer

• US 4,770,236 A
• Filed: 03/18/1987
• Issued: 09/13/1988
• Est. Priority Date: 03/18/1987
• Status: Expired due to Fees

• Current Assignee: Buffalo Technology (USA) Incorporated (Melco Holdings Incorporated)
• Original Assignee: Blaw-Knox Food and Chemical Equipment Incorporated
• Inventors: Kulikowski, Ronald A.
• Primary Examiner(s): Yeung, James C.
• Application Number:
  US07/027,346
• Time in Patent Office: 545 Days
• Field of Search: 165/89, 165/181, 165/92, 165/86, 165/93, 165/87, 165/94, 165/91, 34/183, 34/179, 34/180, 34/181, 34/182, 34/124, 34/125, 34/140-142, 432/31, 432/112, 366/144, 366/147, 366/149, 366/325
• US Class Current: 165/86
• CPC Class Codes: F26B 17/20 the axis of rotation being horizontal or slightly inclined
• CPC Class Codes: F26B 23/10 using tubes or passages containing heated fluids , e.g. acting as radiative elements; Closed-loop systems for combustion gases F26B3/305
• CPC Class Codes: F28F 5/04 Hollow impellers, e.g. stirring vane
• CPC Class Codes: Y10S 165/15 Radial or axial impeller

Abstract

A paddle type rotary dryer includes a hollow shaft and a plurality of tubular members for interconnecting the interior of a shaft with the interior of each of the paddles. The tubular members extend inwardly into the shaft and prevent the flow of condensate from the shaft into the paddles when the paddles are below the shaft. The tubular members also extend outwardly into the hollow portion of each of the paddles for directing steam into the paddles and define an open passageway or slot so that liquid condensate is drained from the paddles and into the shaft when the vanes are disposed above the shaft, and a fluid conduit is adapted to maintain the level of liquid condensate in the shaft at a height which is less than the height of the inwardly directed tubular member.

Claims

1. A rotary dryer comprising a stationary vessel and a hollow rotatable shaft disposed in said vessel along its longitudinal axis for rotation therein, means for rotating said hollow shaft and fluid conduit means for delivering steam, or other vaporized liquid into the interior of said hollow shaft, a plurality of heat exchange assemblies each of which includes a plurality of hollow vanes fixed to said shaft for rotation therewith, tubular means interconnecting the interior of said shaft with the interior of each of said vanes for directing steam from said shaft and into said vanes, said tubular means extending inwardly into said shaft for preventing the flow of condensates from said shaft into said vanes when said vanes are disposed below said shaft, means defining a hollow member extending outwardly and into the hollow portion of each of said vanes and defining a pair of open elongated slots in a wall of each of said hollow members in close proximity to said shaft for draining liquid condensate from said vanes into said hollow shaft when said vanes are disposed above said shaft, and means for removing liquid condensate from said shaft and maintaining the level of liquid condensate in said hollow shaft at a level less than the height of said inwardly directed tubular means.

2. A rotary dryer according to claim 1 wherein six vanes are disposed in groups disposed at intervals along said shaft and in which said means for removing liquid condensate from said shaft and maintaining the level of liquid condensate in said hollow shaft at a level less than the height of said inwardly directed tubular means includes a stationary pipe with one end thereof disposed within a lower portion of said hollow shaft at a distance from the bottom of said shaft which is less than the height of said inwardly directed tubular means.

3. A paddle dryer according to claim 2 which includes at least 4 assemblies each of which includes 6 vanes.

4. A paddle dryer according to claim 6 wherein each of the vanes is inclined at an angle of between 5°

and 45°

along an axis that is perpendicular to the longitudinal axis of said shaft and with the blades of the vanes approximately parallel to one another so that rotation of the shaft and vanes moves treated material from one end of said vessel toward the other end thereof.

5. A rotary dryer comprising a stationary horizontal vessel including a lower portion having a semicircular cross section along the length thereof and a pair of vertical side walls extending upwardly from said semicircular lower portion, a pair of vertical end walls and a cover for enclosing the vessel, an inlet opening adapted to receive material for drying disposed in an upper portion of the vessel at one end thereof and means including an opening in said cover for evacuating vapors from said vessel, means for discharging material from said vessel disposed in a lower portion thereof at a second end of said vessel which is opposite the inlet opening, and a hollow rotatable shaft and mounting means including a pair of bearings for mounting said shaft within said vessel for rotation therein and means for preventing treated material from leaking out of the vessel in the area that said shaft passes through said end walls, fluid conduit means for delivering steam into the interior of said hollow shaft and a plurality of heat exchange assemblies disposed along and fixed in said shaft for rotation therewith, each of said heat exchange assemblies including six radially extending and generally parallel hollow vanes disposed circumferentially about said shaft and offset from each other by about 60°

, each of said vanes inclined at an angle of about 15°

to a plane which is perpendicular to the axis of the shaft so that rotation of the shaft and vanes will heat and propel material from one end of said vessel toward said discharge means, tubular means interconnecting the interior of said shaft with the interior of each of said vanes for directing steam from said shaft and into said vanes, said tubular means extending inwardly into said shaft for preventing the flow of condensate from said shaft into said vanes when said vanes are rotated below said shaft, means defining a hollow member extending outwardly into the hollow portion of each of said vanes and defining a pair of open elongated slots in a wall of each of said hollow members in close proximity to said shaft for draining liquid condensate from said vanes into said hollow shaft when said vanes are rotated above said shaft, and means including a stationary pipe with one end thereof disposed within a lower portion of said hollow shaft at a distance from the bottom of said shaft which is less than the height of said inwardly directed tubular means for removing liquid condensate from said shaft and maintaining the level of liquid condensate in said hollow shaft at a level which is less than the height of said inwardly directed tubular means.