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A thresher for oilseed and other crops
J. agric. Engng Res. (1967) 12 (1) 71-74
A Thresher for Oilseed and Other Crops J. G.
KEMP*;
A. G. PLESSERSt; G. B. HERGERT*
1. Introduction The research and breeding programme in progress at the Ottawa Research Station in oilseeds and other crops required a small field thresher capable of handling these crops. Units for threshing soybeans! and flax" and special modifications of commercial units" 4 are described in the literature, but none has sufficient adaptability for handling a variety of crops. A unit designed for wide use must perform efficiently even though the characteristics of the crops vary considerably and seed damage must be minimal in all cases. To achieve this, the threshing and cleaning action must be readily adjustable. Furthermore, the unit should have the capacity to handle single plants or bulk material, and rapid inspection and cleaning between samples should be possible. A portable field thresher which has been used successfully for a wide variety of oilseeds and other crops, is described. 2. Construction The unit has a steel frame mounted on wheels and is equipped with a tractor hitch, a wheeled screw jack at the front and an adjustable stand at the rear. The overall size is 50 x 140 x 72 in high (Fig. 1). The unit is powered by a 2-cylinder, 12 hp petrol engine equipped with a centrifugal clutch in the drive pulley. The feed rolls (Fig. 2, A) rupture the seed pods, partially separate the seed and feed material to the cylinder, holding it while it is flailed by the cylinder. The top 4·125 in dia rubber-coated roll rotates in spring-loaded bearings while the bottom 4·5 in dia steel roll rotates in fixed bearings. The spring tension on the top roll and the gap between the rolls are adjustable. The bottom roll is driven by a chain from a gearbox (B) and the top roll by a flexible coupling (Fig. 1, bottom) from the bottom roll to a second gearbox (C) and then via universal joints and a telescoping shaft to allow free movement of the top roll. Both rolls rotate at 50 rev/min in opposite directions but the difference in diameter of the rolls result in a differential peripheral speed which causes a tearing action on material between the rolls. The gearbox (B) has forward and reverse drive. The change lever is connected to a pressure bar (D) above the loading chute (E) close to the inlet to the rolls. Pressure against the bar reverses the direction of the rolls so that the rolls can be cleared if overloading occurs or in case of emergency. Spring-loading in the gearbox plus the forces exerted by the gears, automatically return the change lever to the forward drive position. The angle-bar type cylinder (F) is 15 in dia and 20 in long with rubber-faced bars. The ends are closed to prevent trapping seed in the interior of the cylinder. The cylinder operates as an undershot unit against a rubber-faced shelling plate (G), which pivots on the shaft of the steel feed roll; clearance between the cylinder and plate is adjusted by turning the plate. The adjustment is made outside the thresher body by loosening a nut and operating a lever. The backing of the shelling plate is brass, machined to fit closely against the steel roll to prevent seed loss. The concave (H) is a closed type, not fitted with bars, and extends round part of the cylinder so that the material leaves at an angle of 45° to the horizontal. A variable speed belt drive (J) provides cylinder speeds of 200-950 rev/min. This can be extended to 1200 rev/min by changing the drive pulley and the belt tightening pulley. The cylinder can be adjusted vertically for cylinder-concave clearance, and can be set to make the • Engineering Research Service. Researc h Branch . Canada Department of Agriculture , Ottawa (Contribut ion No. 113) t Ottawa Research Station, Research Branch , Can ada Department of Agriculture, Ott awa (Contribution No . (81)
71
72
A THRESHER FOR OILSEED AND OTHER CROPS
concave self-cleaning. A section of the roof (K) above the rolls and cylinder is hinged to allow quick inspection and cleaning of the roll and cylinder area. The separating section of the thresher is a straw deck (L) and a seed deck (M). Both decks are driven from the same pair of rocker arms but are mounted so that the reciprocating deck forces oppose each other. The drive to the rocker arms is by pitman arranged on a jack-shaft. Both decks are readily accessible for cleaning and inspection (Fig. 1, top right). As material leaves the cylinder and concave, it hits a curved deflection plate (N) which slows the material and directs it down onto the straw deck. Air blast effect from the cylinder is small because the rolls restrict air intake by the cylinder. Therefore, the speed of material leaving the cylinder is easily controlled.
....
I
I
Fig. 1. Side and end view of the thresher and detail of drive to top roll
A segmented curtain (0) controls seed bouncing. Material passing through the no-choke straw sieve is carried to the front of the machine by a seed return pan (P) which is integral with the straw deck. The seed deck is constructed for easy interchange of seed screens by a slide arrangement. Extra screens are carried on top of the machine (Q). The slope of the tailing screen (R) is adjustable and controls the flow and depth of material on the seed screen. The carrying frame of the tailing screen is pivoted so that the complete assembly can be swung upwards out of the way when changing seed screens. An over-centre tension spring holds the assembly in either position (Fig. 1, top right). The exit end of the seed deck is supported on two rollers which run on tracks,
73
J. G. KEMP; A. G. PLESSERS; G. B. HERGER T
arranged so that they pivot in a vertical plane about one end. By this adjustment, the vertical throw of the exit end of seed rack is readily adjusted to meet the various cleaning requirements of different crops. Seed passing through the seed screen falls into a seed cleaning chamber (S). Air blast from a fan (T) blows light material through an adjustable opening at the rear of the chamber. Alternatively, air from the fan can be directed by an adjustable deflector directly onto the seed screen. The amount of air is controlled by inlet control gates on the fan. Three types of pan (U) are used to collect seed: standard, screened bottom and small sample pans. The pans slide into position at the bottom of the seed cleaning chamber. The screened bottom pan is used when threshing bean plants that have been har vested by pulling. Soil from the roots which would normally enter the seed pan passes through the screen. The small sample pan is used for small volumes of seed and is fitted with a pouring spout for filling envelopes. F K
E
r··' , ....:---
)- .. ~" .:
f- ..
U
_-y
Q
N L
p M R
s -u Fig. 2. The thresher
Compressed air at 100 lb/in", supplied by an air compressor and storage tank, is used to clean the machine between samples. A remo vable platform, which is supported by two telescoping pipes on the frame, is provided for the operator. The feed chute provides an area on which the operator can break or spread bundles for hand feeding. The throttle control is located within easy reach of the operator so that he can control the operation of the centrifugal clutch by engine speed.
3. Performance During 1964-66 the unit was successfully used for threshing a wide variety of oilseed crops (soybeans, safflower, sunflower, flax, camelina), as well as beans , peas and wheat, rye, buckwheat, etc. Seed removal and recovery were excellent and seed damage negligible. The average time required to thresh the crop from one plot was determined from the number of plots threshed in a given time, usually 45-60 min and included the time required to clean the thresher between samples. It ranged from I min 10 s for flax to 2 min 30 s for peas (Table I). Single plants of all crops, except peas, were also threshed at the rate of 40-60 plants per hour, including cleaning time. The cylinder speeds noted are those used under the most favourable conditions in the field while higher speeds were required when the crops were tough. The efficiency of threshing and separation was calculated from the amount of seed lost or unthreshed in relation to the total amount of seed in each sample. The amount of seed loss was
74
A THRESHER FOR OILSEED AND OTHER CROPS TABLE I Average time required, loss of seed and cylinder speed in threshing two rod row plots
Crop
Beans Peas Flax Safflower Crambe Buckwheat Wheat
Time. min 1·75 2'50 1·20 1·50 1·30 1·50 1·75
Cylinder Loss ofspeed, peripheral speed, % ftlmin 0·75 0·10 0·50 0'50 0·10 0·40 0·50
1570 2360 3540 1570 1570 2360 4720
small. Seed damage was estimated by visual inspection and by germination tests in comparison with the damage occurring in hand-threshed samples. Field beans were the most sensitive to damage. However, damage was negligible when the machine was adjusted to suit the condition of the crop. To maintain high efficiency under various conditions, cylinder speed and clearance, roll clearance, spring tension and other adjustments must be made for each crop. The spring loaded feed rolls which performs a partial threshing increases the effectiveness of the cylinder by restraining the material under the action of the cylinder for a longer period. As a result, the cylinder can be operated at lower speeds which results in lower seed damage. The unit can be used for other crops than oilseed although rethreshing may be required for some forage crops. REFERENCES
, Owen, C. W.; Magee, A. I. Development of a soybean plot thresher. Agron. J., 1953,45,387 Cunningham, R. H.; Hannah, A. E. A roller thresher for experimental plot material. Can. J. agric. Sci., 1956, 36 (3) 208 3 Bainer, R.; Winters, J. S. New principle in threshing lima bean seed. Agric. Engng, St Joseph, Mich., 1937, 18 (5) 205 4 Bainer, R.; Winters, J. S. Results oftests ofa rubber roller seed bean thresher. Agric. Engng, St Joseph, Mich., 1938, 19 (6) 251 2
A Thresher for Oilseed and Other Crops J. G.
KEMP*;
A. G. PLESSERSt; G. B. HERGERT*
1. Introduction The research and breeding programme in progress at the Ottawa Research Station in oilseeds and other crops required a small field thresher capable of handling these crops. Units for threshing soybeans! and flax" and special modifications of commercial units" 4 are described in the literature, but none has sufficient adaptability for handling a variety of crops. A unit designed for wide use must perform efficiently even though the characteristics of the crops vary considerably and seed damage must be minimal in all cases. To achieve this, the threshing and cleaning action must be readily adjustable. Furthermore, the unit should have the capacity to handle single plants or bulk material, and rapid inspection and cleaning between samples should be possible. A portable field thresher which has been used successfully for a wide variety of oilseeds and other crops, is described. 2. Construction The unit has a steel frame mounted on wheels and is equipped with a tractor hitch, a wheeled screw jack at the front and an adjustable stand at the rear. The overall size is 50 x 140 x 72 in high (Fig. 1). The unit is powered by a 2-cylinder, 12 hp petrol engine equipped with a centrifugal clutch in the drive pulley. The feed rolls (Fig. 2, A) rupture the seed pods, partially separate the seed and feed material to the cylinder, holding it while it is flailed by the cylinder. The top 4·125 in dia rubber-coated roll rotates in spring-loaded bearings while the bottom 4·5 in dia steel roll rotates in fixed bearings. The spring tension on the top roll and the gap between the rolls are adjustable. The bottom roll is driven by a chain from a gearbox (B) and the top roll by a flexible coupling (Fig. 1, bottom) from the bottom roll to a second gearbox (C) and then via universal joints and a telescoping shaft to allow free movement of the top roll. Both rolls rotate at 50 rev/min in opposite directions but the difference in diameter of the rolls result in a differential peripheral speed which causes a tearing action on material between the rolls. The gearbox (B) has forward and reverse drive. The change lever is connected to a pressure bar (D) above the loading chute (E) close to the inlet to the rolls. Pressure against the bar reverses the direction of the rolls so that the rolls can be cleared if overloading occurs or in case of emergency. Spring-loading in the gearbox plus the forces exerted by the gears, automatically return the change lever to the forward drive position. The angle-bar type cylinder (F) is 15 in dia and 20 in long with rubber-faced bars. The ends are closed to prevent trapping seed in the interior of the cylinder. The cylinder operates as an undershot unit against a rubber-faced shelling plate (G), which pivots on the shaft of the steel feed roll; clearance between the cylinder and plate is adjusted by turning the plate. The adjustment is made outside the thresher body by loosening a nut and operating a lever. The backing of the shelling plate is brass, machined to fit closely against the steel roll to prevent seed loss. The concave (H) is a closed type, not fitted with bars, and extends round part of the cylinder so that the material leaves at an angle of 45° to the horizontal. A variable speed belt drive (J) provides cylinder speeds of 200-950 rev/min. This can be extended to 1200 rev/min by changing the drive pulley and the belt tightening pulley. The cylinder can be adjusted vertically for cylinder-concave clearance, and can be set to make the • Engineering Research Service. Researc h Branch . Canada Department of Agriculture , Ottawa (Contribut ion No. 113) t Ottawa Research Station, Research Branch , Can ada Department of Agriculture, Ott awa (Contribution No . (81)
71
72
A THRESHER FOR OILSEED AND OTHER CROPS
concave self-cleaning. A section of the roof (K) above the rolls and cylinder is hinged to allow quick inspection and cleaning of the roll and cylinder area. The separating section of the thresher is a straw deck (L) and a seed deck (M). Both decks are driven from the same pair of rocker arms but are mounted so that the reciprocating deck forces oppose each other. The drive to the rocker arms is by pitman arranged on a jack-shaft. Both decks are readily accessible for cleaning and inspection (Fig. 1, top right). As material leaves the cylinder and concave, it hits a curved deflection plate (N) which slows the material and directs it down onto the straw deck. Air blast effect from the cylinder is small because the rolls restrict air intake by the cylinder. Therefore, the speed of material leaving the cylinder is easily controlled.
....
I
I
Fig. 1. Side and end view of the thresher and detail of drive to top roll
A segmented curtain (0) controls seed bouncing. Material passing through the no-choke straw sieve is carried to the front of the machine by a seed return pan (P) which is integral with the straw deck. The seed deck is constructed for easy interchange of seed screens by a slide arrangement. Extra screens are carried on top of the machine (Q). The slope of the tailing screen (R) is adjustable and controls the flow and depth of material on the seed screen. The carrying frame of the tailing screen is pivoted so that the complete assembly can be swung upwards out of the way when changing seed screens. An over-centre tension spring holds the assembly in either position (Fig. 1, top right). The exit end of the seed deck is supported on two rollers which run on tracks,
73
J. G. KEMP; A. G. PLESSERS; G. B. HERGER T
arranged so that they pivot in a vertical plane about one end. By this adjustment, the vertical throw of the exit end of seed rack is readily adjusted to meet the various cleaning requirements of different crops. Seed passing through the seed screen falls into a seed cleaning chamber (S). Air blast from a fan (T) blows light material through an adjustable opening at the rear of the chamber. Alternatively, air from the fan can be directed by an adjustable deflector directly onto the seed screen. The amount of air is controlled by inlet control gates on the fan. Three types of pan (U) are used to collect seed: standard, screened bottom and small sample pans. The pans slide into position at the bottom of the seed cleaning chamber. The screened bottom pan is used when threshing bean plants that have been har vested by pulling. Soil from the roots which would normally enter the seed pan passes through the screen. The small sample pan is used for small volumes of seed and is fitted with a pouring spout for filling envelopes. F K
E
r··' , ....:---
)- .. ~" .:
f- ..
U
_-y
Q
N L
p M R
s -u Fig. 2. The thresher
Compressed air at 100 lb/in", supplied by an air compressor and storage tank, is used to clean the machine between samples. A remo vable platform, which is supported by two telescoping pipes on the frame, is provided for the operator. The feed chute provides an area on which the operator can break or spread bundles for hand feeding. The throttle control is located within easy reach of the operator so that he can control the operation of the centrifugal clutch by engine speed.
3. Performance During 1964-66 the unit was successfully used for threshing a wide variety of oilseed crops (soybeans, safflower, sunflower, flax, camelina), as well as beans , peas and wheat, rye, buckwheat, etc. Seed removal and recovery were excellent and seed damage negligible. The average time required to thresh the crop from one plot was determined from the number of plots threshed in a given time, usually 45-60 min and included the time required to clean the thresher between samples. It ranged from I min 10 s for flax to 2 min 30 s for peas (Table I). Single plants of all crops, except peas, were also threshed at the rate of 40-60 plants per hour, including cleaning time. The cylinder speeds noted are those used under the most favourable conditions in the field while higher speeds were required when the crops were tough. The efficiency of threshing and separation was calculated from the amount of seed lost or unthreshed in relation to the total amount of seed in each sample. The amount of seed loss was
74
A THRESHER FOR OILSEED AND OTHER CROPS TABLE I Average time required, loss of seed and cylinder speed in threshing two rod row plots
Crop
Beans Peas Flax Safflower Crambe Buckwheat Wheat
Time. min 1·75 2'50 1·20 1·50 1·30 1·50 1·75
Cylinder Loss ofspeed, peripheral speed, % ftlmin 0·75 0·10 0·50 0'50 0·10 0·40 0·50
1570 2360 3540 1570 1570 2360 4720
small. Seed damage was estimated by visual inspection and by germination tests in comparison with the damage occurring in hand-threshed samples. Field beans were the most sensitive to damage. However, damage was negligible when the machine was adjusted to suit the condition of the crop. To maintain high efficiency under various conditions, cylinder speed and clearance, roll clearance, spring tension and other adjustments must be made for each crop. The spring loaded feed rolls which performs a partial threshing increases the effectiveness of the cylinder by restraining the material under the action of the cylinder for a longer period. As a result, the cylinder can be operated at lower speeds which results in lower seed damage. The unit can be used for other crops than oilseed although rethreshing may be required for some forage crops. REFERENCES
, Owen, C. W.; Magee, A. I. Development of a soybean plot thresher. Agron. J., 1953,45,387 Cunningham, R. H.; Hannah, A. E. A roller thresher for experimental plot material. Can. J. agric. Sci., 1956, 36 (3) 208 3 Bainer, R.; Winters, J. S. New principle in threshing lima bean seed. Agric. Engng, St Joseph, Mich., 1937, 18 (5) 205 4 Bainer, R.; Winters, J. S. Results oftests ofa rubber roller seed bean thresher. Agric. Engng, St Joseph, Mich., 1938, 19 (6) 251 2