I. Answer the following questions:

1. How are the straw and grain handled in the typical combine?

2. What are the combine mechanisms adjusted for and how?

3. How are the combine mechanisms operated?

4. What parts of the combine should be serviced regularly?

5. What are the advantages of the combine as compared to the binder and a stationary thresher?

6. Does combining have any disadvantages? If so, what are they?

7. Most all combines have a provision for easily and quickly varying the speed of the cylinder. Why? Describe one method.

8. Will a certain cylinder speed always be the correct speed for one particular crop – such as wheat, for instance?

9. Assume that you are having the following troubles: cracked grain, poorly cleaned grain, tailings auger overloaded, unthreshed grain heads, threshed grain goes out with straw. What adjustments would you make to remedy them?

10. For what crops or what conditions would you prefer a combine equipped with a pick-up attachment?

II. List in order the principal parts which the cut grain, the straw, and the threshed grain pass through during the combining operation.

III. Explain fully how you would inspect and test a combine to determine what repairs and reconditioning work might be needed.

IV. Describe how you would prepare a combine engine for storage.

V. Comment on the following numbers:

1) 15; 2) 350; 3) 75; 4) 20; 5) 1600

VI. Mark true or false sentences and correct the false ones:

1. His service shop can do the best work for you all the season.

2. Run it loaded long enough to work out all straw, dirt, and chaff. If you leave such residues in they hold moisture and cause rust.

3. If you want it to last long and give trouble-free service, you mustn’t lubricate it effectively.

4. But you needn’t have to vary these speeds for your different crops and crop conditions.

5. The sieve is usually placed in the shoe with a slight angle downward, toward the grain auger.

6. The straw rack should protect the grain that is mixed with straw.

7. Adjust the clearance between the header and concaves.

8. The platform auger used in some models is adjustable vertically; raise it for heavy crops and lower it for light crops.

9. Cutting too high may overload the combine, speed up your rate of work, and make separation difficult.

10. If you do not want to save the straw, set the reel as high as possible without missing any heads.

VII. Read the text, translate it and give a short summary of the text: Threshing and Separating systems (continued)

Claas has expended its Lexion model series to include smaller machines with 5 or 6 walkers. These combines feature a threshing system with an additional drum situated before the threshing cylinder. The diameter of the actual threshing cylinder amounts to 600mm. Sampo offers a threshing system with an additional drum in front of the threshing cylinder for its new models. This is a combine with 5 walkers, a cylinder width of 1.11 m, and an engine power of 135kW. Eimer reports on the results of trials conducted to establish grain separation. Measuring the torque of the threshing drum is a possible indirect method of establishing the throughput. Trials in Hungary, however, didn’t show any correlation between the torque of the threshing drum, the yield, and the supply of nutrients to the soil. Tine-chain and tine-rotor walkers as an alternative to the walker have been studied in Dresden. In addition to the capacity and the overall impression of the machine, good service is an important criterion that prospective buyers should consider when purchasing a combine. The most important criteria can be listed in a quality profile.

The demands on the cleaning system have significantly increased in recent years, with regard to both the throughput and purity. Grain-flow sensors, installed under the chaffer (and under the threshing concave and the walker), permit the separating function to be established during operation and thus enable conclusions to be drawn on materials flows and the strain on the cleaning system. This information can be used to control the fan rpm. Neutral networks can improve the control of air-flow separating systems, evidenced by an example from the recycling industry. Air assistance can increase the capacity of flat-sieve cleaners with a directly excited wire gauze, which are used in mechanical process engineering. Profiled sieves can be advantageous for cleaning systems. This also applies to intensive pre-separation of the material in a horizontal air flow.

The calculation of parameters and the simulation of separating processes are expected to reduce the time and the expenses required to design efficient cleaning systems. Possible parameters include the relative speed of impact, the gliding speed, normal acceleration, and the conveying speed, for example. Simulation is based on the superposition of convection and dispersion of the grains in the MOG layer.

The physical properties of the grain and the MOG significantly influence the separating capacity. Physical properties can also be used for the indirect measurement of characteristics such as moisture or for the classification of the grain crop.