NOVELTY - Composter comprises elongated hollow drum mounted for rotation; intake end wall (68) fixed at intake end of the drum; exit end wall fixed at exit end of the drum; drive mechanism for rotating drum; first external trunnion ring (42) coaxial with axis of rotation; first and second pairs of idler rollers (12, 14) supporting the drum, and including frusto-conical rings each having large and small circular edges, each meeting at different locations of drum; where first two locations are on opposite sides of intake end wall, and third and fourth locations are on opposite sides of exit end wall.    USE - As large-scale composting apparatus for producing usable compost from plant and animal matter collected from farm and meat packing plant.    ADVANTAGE - The present composter allows operator to introduce new material at any desired time, and at any desired rate within wide range, all while the composter is in continuous operation. By positioning annular intake and exit end walls in axial register with external trunnion rings on the drum, the end walls can serve as reinforcements, making it possible to reduce the weight of the drum. The rubber lining reduces corrosion and improves uniformity of residence time. The relationship between supporting rollers and trunnion rings can allow for thermal expansion and contraction of the composter drum while ensuring that the sealing relationship between the intake end wall and the stationary end plate is maintained. In addition, the frusto-conical rings inhibit relative motion of the end walls and the cylindrical wall of the drum and this protects the apparatus against failure due to metal fatigue. Corrosion of the chambers formed by the frusto-conical rings is avoided by introducing corrosion-inhibiting fluid through fittings provided in the ring elements.    DETAILED DESCRIPTION - Composter comprises elongated hollow drum having cylindrical wall, the drum being mounted for rotation on axis, and having axially spaced intake and exit ends. The intake end wall (68) is fixed to cylindrical wall and extending inward toward axis from location adjacent part of cylindrical wall at intake end of the drum, where intake end wall is rotatable with drum and having side facing interior space of drum and intake opening for passage of material into interior space of drum. The exit end wall is fixed to cylindrical wall and extending inward toward axis from location adjacent a part of cylindrical wall at exit end of drum; where exit end wall is rotatable with drum and having central exit opening for delivery of material from interior space of the drum. The composter comprises drive mechanism for rotating the drum about axis; first external trunnion ring on cylindrical wall of drum adjacent its intake end and second external trunnion ring on cylindrical wall of drum adjacent its exit end, where trunnion rings (42) are coaxial with axis of rotation. The composter comprises first and second pairs of idler rollers (12, 14) rotatably supporting the drum, the first pair of rollers are in rolling engagement with first external trunnion ring, and the second pair of rollers are in rolling engagement with second external trunnion ring; in which first external trunnion ring extends axially from first edge of first trunnion ring to second edge of first trunnion ring spaced axially from first edge; in which second external trunnion ring extends axially from first edge of second trunnion ring to second edge of second trunnion ring spaced axially from first edge; in which intake end wall is surrounded by first external trunnion ring and located at axial location between axial locations of first and second edges of first external trunnion ring, and the exit end wall is surrounded by second external trunnion ring and located at axial location between the axial locations of the first and second edges of the second external trunnion ring; and further includes a first frusto-conical ring having large and small circular edges, the large circular edge meeting the internal surface of the cylindrical wall of the drum at first location and the small circular edge of first frusto-conical ring meeting the intake end wall at location spaced radially inward toward axis from internal surface of the cylindrical wall of the drum; second frusto-conical ring having large and small circular edges, the large circular edge meeting the internal surface of the cylindrical wall of the drum at a second location and the small circular edge of the second frusto-conical ring meeting the intake end wall at location spaced radially inward toward axis from internal surface of cylindrical wall of the drum; third frusto-conical ring having large and small circular edges, the large circular edge meeting the internal surface of the cylindrical wall of the drum at third location and the small circular edge of the first frusto-conical ring meeting the exit end wall at a location spaced radially inward toward axis from internal surface of cylindrical wall of the drum; and fourth frusto-conical ring having large and small circular edges, the large circular edge meeting the internal surface of the cylindrical wall of the drum at a fourth location and the small circular edge of the second frusto-conical ring meeting the exit end wall at a location spaced radially inward toward axis from internal surface of the cylindrical wall of drum; where first and second locations are on opposite sides of intake end wall, and third and fourth locations are on opposite sides of the exit end wall.    DESCRIPTION OF DRAWING(S) - The figure shows elevational view of the intake end of composter.    Cylindrical drum (10)    Rollers (12, 14)    Hopper (20)    Trunnion rings (42)    Blower (57)    Brackets (64, 66)    End wall (68)    Metal fatigue (69)