GB2043422A - Apparatus for threshing crops - Google Patents

Abstract

An apparatus for threshing has a threshing drum 11 rotatably retained in a housing provided with a crop inlet 18, a threshing basket 14, a collecting and discharge channel 23 for grain and a separating channel. Threshing elements 13 in housing cooperate with threshing pins strips 12 on the outside of the threshing drum. Cross-current blower means, which may be constituted by vanes 1 mounted on the threshing drum or by a separate cross-current blower inside the threshing drum, establish a flow of air through the crop inlet to the separating channel through a threshing zone. <IMAGE>

Description

SPECIFICATION Apparatus for threshing crops The invention relates to an apparatus for threshing crops.

Threshing apparatus may be used for graintype crops such as cereals, rice, sorghum etc.

Threshing apparatus may include means for separating the yield obtained by means of an air current and mechanical separating facilities.

The Dutch Patent Specification 7701151 discloses a threshing drum designed as a centrifugal blower, air suction openings being provided in the faces of the threshing drum.

Over the entire circumference of the threshing drum the axially sucked-in air flows approximately radially through correspondingly shaped vane channels from inside to outside, whereby the air outflow is strongest in the centre section, if viewed along the length of the threshing drum.

According to the invention there is provided apparatus for threshing crops including (A) a housing having first threshing means, an inlet for crops, a threshing basket, a collecting and discharge channel and a separating channel, and (B) a rotatable threshing drum having second threshing means and a cross-current blower means for conveying air from the inlet through a threshing zone between the drum and the housing to the separating channel.

The circumference of the drum is retained inside the stationary housing. The second threshing means may be threshing strips, pins etc on the outside wall of the threshing drum and the second threshing means can thus cooperate with stationary threshing elements forming the first threshing means on the inside of the threshing basket which may be sieve-like and partially and concentrically surround the threshing drum. The threshing basket can have a collecting and discharging channel for the threshed yield falling through the threshing basket arranged underneath it, whilst the threshing zone can be formed between the threshing drum and the threshing basket.The threshing zone is thus connected to the inlet for the crop to be threshed and leads into a separating channel into which the threshed mixture consisting of straw, chaff and some remaining yield is channelled by the action of the kinetic energy and the blower air current. Further separation of the mixture can thus take place in the separating channel.

Over-pressure can be prevented from forming in the housing covering the threshing drum and air does generally not leave through the crop inlet. Instead a suction effect, particularly favourable to the introduction of the crop, is created in the crop inlet. Furthermore the sucked-in air can flow approximately evenly along the the threshing drum into the separating channel with a reduced incidence of turbulence at this point.

The air throughput effected by the crosscurrent blower means is dependent upon the number of revolutions of the cross-current blower means. In order to accommodate the various crops and particularly in view of the varying moisture content of crops, it is sometimes necessary to change the number of revolutions or circumferential speed of the threshing drum. It is advantageous if, in addition to the crop inlet there is a separate air suction opening for the cross-current blower means. With this arrangement it is advantageous to provide a facility by means of which the cross-section of the air suction opening may be varied. This facility may conveniently consist of adjustable louvres.In this way the air throughput can be adjusted at a given blower speed and can thus be adapted for each case in such a way as to ensure a satisfactory air flow through the mixture and a further optimum yield separation in the separating channel.

Threshing drum and cross-current blower means may be formed by one single rotary part, whereby the blower vanes can be incorporated in the threshing drum wall. However, cases are conceivable, where the threshing drum is required to rotate at low speed, yet where, despite any additional adjustable air suction openings, the maximum obtainable air throughput is not sufficient. In this case it is advantageous, if the cross-current blower means is arranged as a separate component inside the threshing drum and can be driven at a different speed from that of the drum.

Whereas the cross-current blower means may be non-rotatably connected to the shaft, the threshing drum may be mounted so as to be freely rotatable on the same shaft. Threshing drum and shaft may each be driven via a separate belt drive at varying rotational speeds. This has the effect that the air throughput becomes completely independent from the speed of the threshing drum, without substantially diminishing the advantages of air being sucked in at the inlet and passing in an approximately even flow along the threshing drum.

It is advantageous if the approximately downward-pointing collecting and discharging channel for the threshed yield has at least one lower air suction opening. With this arrangement the said opening may be formed by a side discharge opening for the yield. Since the air current produced by the cross-current blower flows approximately horizontally, i.e.

vertically to the channel axis in the area of the upper feed opening of the collecting and discharging channel, an under-pressure is created at this point. Due to this under-pressure air is sucked upwards through the said lower air suction opening or the side discharge opening into the threshing drum. Thus the yield falling downwards through the threshing basket can be acted upon by the said suction air current flowing in the opposite direction, thus helping to separate chaff and other lightweight straw particles from the yield. In this way a surprisingly clean yield can be obtained.

In addition there may be a container for receiving a mixture of chaff and yield, whereby an open bottom of the container is connected to an entry opening of the collecting and discharging channel. The mixture remaining in the separating channel after the additional yield separation may still to contain some yield. This mixture can be directed into the aforesaid container. The material leaving the bottom of this container is acted upon, as previously described by the air suction current flowing upwards in an approximately vertical direction in the collecting and discharging channel, so that the yield can be further separated from impurities with a lighter specific gravity. By this simple method a further separating stage is created. The yield thus separated has again a surprisingly high degree of purity.

Turbulences which may adversely affect the flow of air passing through the mixture are reduced and further yield separation is facilitated. Overpressure created in the housing surrounding the threshing drum may be reduced, so inhibiting air flowing out through the crop inlet in a direction opposite to the incoming crop to be threshed and facilitating the smooth introduction of the crop.

The separating effect during yield separation introduction of the crop material can be improved.

DRAWINGS Figure 1 is a cross-section illustrating the principle of a cross-current blower arranged in a housing for use in a threshing device according to the invention; Figure 2 is a side view and partial crosssection of a threshing apparatus according to the invention; Figure 3 is a modified cross-section of another threshing apparatus according to the invention; Figure 4 is a partial side view of another threshing apparatus according to the invention; and Figure 5 is a longitudinal section of the apparatus of Fig. 4.

With reference to Fig. 1, a cross-current blower or fan consists of a vane ring 1 of overall cylindrical form rotatably mounted on a centric shaft 2, and a housing 3 surrounding the vane ring 1. The housing 3 comprises a main suction opening 4, additional air suction openings 5 and an air outlet opening 6.

The direction of rotation of the vane ring 1 is marked by an arrow 7, whilst the path of the air current created by the cross-current blower is symbolised by an arrow 8. Some air may pass in a generally diametrical direction through the vane ring.

Fig. 2 shows an apparatus for threshing crops such as cereals, rice etc. and for the separation of the threshed yield by means of an air current and mechanical separation. The apparatus comprises a threshing drum 11 driven via a motor 9 and a V-belt 10. The threshing drum 11 is arranged so as to provide an effect equivalent to the vane ring 1 of the cross-current blower of Fig. 1 and is also fitted with threshing teeth 1 2. The teeth 1 2 cooperate with stationary threshing teeth 13, which can be inclined in an adjustable manner, and which are arranged on the inside of a sieve-like threshing basket 14 concentrically surrounding part of the threshing drum 11.

The faces of the threshing drum 11 mounted on a rotatable shaft 1 6 are covered by discs 1 5. The circumference of the threshing drum 11 is partially covered by a stationary housing 1 7. The housing 1 7 has an inlet 1 8 for the introduction of the crop to be threshed. This inlet 1 8 is connected to a threshing zone 1 9 formed between threshing drum 11 and threshing basket 14.The zone 1 9 leads a separating channel 20 which is slightly curved and has projections or baffles 21 fitted on the top of the inside wall for assisting in the separation of the yield left over in the already threshed mixture, for example by redirecting the yield to the inside of the housing, when the yield collides with the baffles 21.

A separate air suction opening 5 is provided next to the inlet 1 8 in the housing 1 7. The cross-section through which air can be sucked in may be varied by adjustable louvres 22.

A collecting and discharging channel 23 is provided below the threshing basket 14 for the threshed yield falling through the threshing basket 14. The lower part of the wall of the separating channel 20 also defines a passage which leads into this channel 23. The lower end of the said channel 23 is connected to a collecting container 24 for the yield.

The air current illustrated in Fig. 1 by arrow 8, is also obtained with the threshing drum 11 illustrated in Fig. 2. Thus crop introduced at inlet 1 8 is passed to the threshing zone 1 9 aided by the suction effect of the air current.

A large part of the yield obtained here falls through the threshing basket 14 into the collecting and discharging channel 23 or the collecting container 24. The remaining mixture of straw, chaff and left-over yield is carried into the separating channel 20 under the influence of the centrifugal force and the cross-current air flow. In the channel 20 a large part of the leftover yield is separated from the mixture with the help of the baffles 21. This yield slides along the lower wall of the separating channel 20 thus also reaching the collecting and discharging channel 23 or the collecting container 24.

The modified embodiment of Fig. 3 differs from that of Fig. 2 only in that a vane ring 1 is arranged as a separate component inside the threshing drum 11 and may be driven at a different speed from the drum. Thus the cross current blowing function and threshing function are performed by different components.

With reference to in Figs. 4 and 5, the collecting and discharging channel 23 for the threshed yield, is arranged in an at least approximately vertical downward direction and is closed off at the bottom. The channel 23 has a lower air suction opening 25 which, in the illustrated example, is formed by the side discharge opening for the yield. The exchange of a'ir between the channel and the outside atmosphere takes place via this opening, so that, as a result of the under-pressure created by the cross-current 8 at the upper entry end of the said channel, air is sucked in a vertical upward direction through the air suction opening 25. This air current flows against the yield falling downwards through the channel 23 and carries away impurities with a lighter specific gravity contained in the yield upwards.

Figs. 4 and 5 show a container 26 for receiving a mixture of chaff and yield, the open bottom 27 of which is joined to an entry opening 28 of the collecting and discharging channel 23. The material falling through the said bottom 27 and the entry opening 28 into the collecting and discharging channel 23 is also acted upon by the air current sucked vertically upwards and can thus cleaned from impurities in the same way.

Claims (11)

1. Apparatus for threshing crops including (A) a housing having first threshing means, an inlet for crops, a threshing basket, a collecting and discharge channel and a separating channel, and (B) a rotatable threshing drum having second threshing means and a cross-current blower means for conveying air from the inlet through a threshing zone between the drum and the housing to the separating channel.

2. Apparatus according to claim 1, in which at least one air suction opening is provided for the cross-current blower in addition to the crop inlet.

3. Apparatus according to claim 2, in which means are provided for varying the suction cross-section of the air suction opening.

4. Apparatus according to claim 3, in which the means for varying the suction crosssection are adjustable louvres.

5. Apparatus according to any of claims 2 to 4 in which the air suction opening is adjacent to and upstream of the crop inlet.

6. Apparatus according to any of the preceding claims, in which the cross-current blowing means includes a cross-current blower arranged inside the threshing drum which blower is drivable at a speed varying from that of the threshing drum.

7. Apparatus according to any of the preceding claims 1 to 6 in which the crosscurrent blowing means includes vanes mounted on and rotatable conjointly with the threshing drum.

8. Apparatus according to any of the preceding claims in which the collecting and discharging channel for the threshed yield extends downwardly and is equipped with at least one lower air suction opening.

9. Apparatus according to claim 8 in which the said air suction opening in the channel is formed by a side discharge opening for the yield.

1 0. Apparatus according to claim 8 or claim 9 in which there is provided a container for receiving a mixture of chaff and yield having an open bottom which is joined to an air suction opening in the collecting and discharging channel.

11. Apparatus for threshing substantially as described with reference to and as shown in Fig. 2.

1 2. Apparatus for threshing substantially as described with reference to and as shown in Fig. 3.

1 3. Apparatus for threshing substantially as described with reference to as shown in Figs. 4 and 5.