The present invention is a drying machine for the drying of vegetable and mineral materials which can be rinsed, for example, corn, and is of the type comprised for the most part of a horizontal drying section which rotates on its own longitudinal axis and through which hot air is led. It is constructed in such a way that when the section rotates, the material passes through it from one end, the inlet end, to the other end, the discharge end, with or against the drying air.

Such machines produce the heat for the drying process in an oven section which can be fired with oil or solid fuel and which opens directly into one end of the drying section. The material is fed into the machine by the rotation of the drying section and is dried as it passes through this by the hot air from the oven and by the fact that a large part of the water in the corn near the oven will evaporate due to the heat radiating from this.

In the currently available equipment, the material is fed into the machine by means of the drying machine being slightly tilted in relation to the horizontal, and/or by means of angled paddles in the sides of the drying machine pushing the material forward or by changing the rotating speed of the drum. These methods can be detrimental to the flow of the material.

The disadvantage of these methods is that it is not possible without additional cost and practical difficulties to regulate the speed at which the material is moved forward and thereby the time spent in the drying section while the machine is in operation, which is necessary when small-grained and large-grained materials are treated alternately. If it is necessary to change the degree to which the drying machine is tilted, there can be difficulties in connecting the conveyors for removal of the dried corn. If it is necessary to alter the speed of rotation in the drying section, investments in thyristor

controls or static frequency transformers, which cause a poor flow, must be made.

The purpose of the present invention is, therefore, to make available a drying machine in which the speed at which the material is brought forward in the drying section can be regulated during operation without these disadvantages.

This is achieved with a corn-drying machine in which the material is brought forward inside the drying section by guide blades which are or can be set at an angle relative to the drying section's longitudinal axis. The guide blades, which are stationary and fixed relative to and inside the drying section, can have a fixed, angled position to bring the material forward at a constant speed, or they can be made so that it is possible to adjust them at different angles in order to alter the speed at which the material is brought forward. Likewise, the individual guide blades can be set at different angles so that the material can pass through the drying section at different speeds.

In addition, the placement of the guide blades in the drying section will cause greater turbulence in the drying air than with the known machines, and the corn will make contact with the heated surfaces of the blades, both of which conditions will increase the drying speed of the corn. It will also be possible to utilise this effect even when the guide blades are not adjustable or if they rotate with the drying section.

By positioning a steering rod, as described in claim 3, in a hollow supporting axle, the present invention makes it possible to control the position of the guide blades in a simple manner, for example to adjust the angle of the guide blades relative to the longtitudinal axis of the drying section in the vertical plane of the axis in such a way that the corn, when it falls on the blades as the section rotates, will be brought more or less forward. The steering rod ^' s function can be to affect

to affect the guide blades attached to the inside of the section or to the steering rod itself. In the latter case the steering rod could be comprised of two co-axial parts which, as when an umbrella is opened, are displaced axially in relation to each other and thereby affect the angle of the blades.

In an especially simple and inexpensive model of the present invention described in claim 4, the guide blades are comprised of a row of parallel and largely flat blades rigidly connected to and angled relative to the steering rod which can rotate in relation to the drying section and which can be locked so that it cannot rotate in relation to the base.

By the positioning of a rotatable axle between the hollow supporting axle and the steering rod which can rotate in relation to these and .on which there are, largely in the same plane, a number of rods running radially from the axle at the free ends of which are hung swinging beaters, as described in claim 3, whole corn, i.e. corn with husks, can be threshed during the drying process by the beaters so that the corn is separated from the chaff. This design has significance when the corn is too wet to be harvested with a combine. This model makes use of a contingency made possible by the hollow supporting axle pursuant to this invention.

In order to riddle the dried material and, for example, the threshed corn, the drying machine described in claim 4 is equipped with a riddling device with at least one riddle of largely cylindrical shape and attached co-axially to the drying section.

By constructing the machine as stated in claim 7, so that there, for example, near one end of and in the side of the drying section is a circular area of openings, it is possible to achieve a suitable feeding of the material in relation to the guide blades and it is likewise possible to expose the material to the

the heat radiating from the oven during the fall through the section.

The present invention will be described in greater detail by an example in the following with reference to the drawings where

Fig. 1 shows a drying machine pursuant to the present invention seen from the side,

Fig. 2 shows a vertical cross section of the machine's oven section,

Fig. 3 shows a vertical cross section of the machine's drying section.

Fig. 4 shows another construction of the oven section seen in cross section from the side, and

Fig. 5 shows a different way of feeding material into the machine pursuant to the present invention.

The drying machine pursuant to the present invention is supported by a base 1, upon which the oven section 2 is fixed and the drying drum 4 is supported with rollers 6 at one end and with a principal bearing 8 at the other end.

The oven section 2 has an oil burner 10 and a solid fuel grate 11 with a row of closely set parallel grate rods 12, the ends of which rest in the sides of the oven. The oven 2 is lined with fire brick 13 and can be fed with fuel from an opening 14 or at the back part 15 of the grate 11. The opening 14 ^' also serves to provide primary air and, during standstill after firing with coal, for the extraction of hot gases with a stream of air in the opposite direction in order to avoid hot gas explosions.

The fuel is fed into the oven with the aid of compressed air or steam which is supplied by the individual grate rods 12 or sections of the grate rods via pipe branches 16 and openings in the direction in which the fuel is fed.

The back edges 19 of the grate rods 12 are serrated or corrugated in profile which makes it possible to feed primary air from the underside of the grate 11 when the grate rods 12 lie closely together, front edge to back edge. By supplying the air in the above-described manner to the grate 11, the pieces of fuel, e.g. coal, are pushed up the inclined top sides of the grate rods 12 and thereby further forward in the oven 2.

The primary air is supplied by a blower 21 on the underside of the oven and around the worm conveyor 22 placed in the bottom which carries the material from a hopper 23 to the drying drum 4.

Inside, the drying drum 4 is divided into a drying section 30 and a riddling section 31, separated by a threshing rotor 32 with beaters 33. The inner sides of the drying section 30 are equipped with carriers 34 parallel to the longitudinal axis of the drum 4. At the junction to the riddling section's (31) smaller inside diameter there are carriers 35, which are twisted in relation to the longitudinal axis of the drum 4.

The guide blades 40, which have a shape approximately equivalent to the inside diameter of the drying section 30, are rigidly mounted on a steering rod 41 which can be adjusted with a hand wheel 42, one end of which is in a seat 43 attached in the oven section 2, and the other end of which is supported by a seat in the hollow threshing axle 44.

The threshing axle 44 can be operated via a sprocket wheel 45 and is again supported in the supporting axle 46 which, in the principal bearing 8, via radially extending rods 47, supports the drying drum 4. The supporting axle 46, and thereby the drum 4, can be made to rotate via a sprocket wheel 48.

The co-axial riddles 48 and 49, which open into a take-up container 50, are attached to the rods 47. In the bottom of the container 50 the worm conveyors 51, 52 and 53 can carry off the riddled material, for example, sand, grain and straw or stone. An air duct 54 for carrying off process air is connected at the top of the container 50.

In another model of the oven 62 with an oil burner 10, the stokehold 64 is shaped like a truncated cone, see Fig. 6, in order to supply more radiant heat to the inside of the drying drum 4.

Instead of feeding the material to be dried via a conveyor 22 in the bottom of the oven 2, one can, in order to avoid scorching or burning of the material due to heat from the oven, feed it through the side of the drum as shown in Fig. 7. There is a band 70 all around the drying drum with several struts 71 between the openings for filling 72, through which the material can fall from a hopper 73. A sloping plate 74 leads the material into the drying drum 4.