AACC-64-70A.pdf

Sampling AACC Method 64-70A Page 1 of 6 Manual Sampling of Wheat and Other Whole Grains Final approval April 13, 1961; Reapproval November 3, 1999 Objective A representative sample is essential for sound inspection and quality analysis This method provides the manual (nonmechanical) means of obtaining a repre- sentative sample from a large mass of grain and similar material. The method is applicable to small grains, corn, and pulses. Apparatus 1. Double-tube compartment probe, constructed of brass or aluminum and consisting of two tubes, one inside the other. Inner tube is divided into compart- ments. Outer tube has slots that match compartment openings of inner tube. When tubes are aligned, bulk grain may enter or be extracted from compart- ments. Designed to draw samples of bulk grain from stationary containers. See Fig. 1. 2. Pelican. Leather pouch, approximately 18 cm deep and 46 cm long, with band of iron inserted along edge to hold pouch open. Pouch is attached to long pole. Designed to catch bulk grain from falling stream. See Fig. 2. 3. Ellis cup. Manual device constructed of lightweight aluminum designed to draw samples from bulk grain moving on conveyor belt. See Fig. 3. 4. Sample divider. Device used to reduce size of sample while representing original sample. Each time sample passes through device, it is divided into two approximately equal portions. Fig. 1. Double-tube compartment probe. Sampling AACC Method 64-70A Page 2 of 6 Manual Sampling of Wheat and Other Whole Grains (continued) Procedure Use of probe 1. Bulk grain in stationary containers (cars, trucks, wagons, or barges) can be sampled with double-tube compartment probe of sufficient length to reach bot- tom of container. In addition to probe, sampling canvas constructed of heavy cloth or similar material 15 cm longer than probe is used. 2. Probe patterns have been established for various containers. They are based on evenly distributing probings in different parts of car, truck, wagon, barge, or Fig. 2. Pelican. Fig. 3. Ellis cup. Sampling AACC Method 64-70A Page 3 of 6 Manual Sampling of Wheat and Other Whole Grains (continued) other container. Each lot shall be probed in as many additional locations as are necessary to assure that the sample is the required size and representative of the lot. Additional probes shall be drawn in a balanced manner. 3 Insert probe at 10-degree angle from vertical with slots facing upward and completely closed. Once inserted, open slots and move probe up and down quickly in two short motions. Close slots completely and withdraw at each depth for uniformity of kind, quality, and condition. 4 When railroad boxcar of bulk grain is probed, probe approximately (A) in center of car; (B) 11.5 m back from doorpost and approximately 0.71.3 m out from side of car; (C) 11.5 m from same end and approximately 0.5 m from opposite side of B; (D) same as (B) except opposite side; and (E) same as (C) except opposite end. See Fig. 4. The slots in the probe face toward the end of the car. 5. When sampling 3-compartment, trough- or door-type hopper cars, insert probe in direction of the arrow at an approximately 10-degree angle. See Fig. 5. The probe may be inserted either in the center of each hopper or slightly off center in order to miss the cross beam. 6. When probing 3-compartment, 10-hatch-type hopper cars, insert probe in the direction of the arrow at approximately 10-degree angle. See Fig. 6. Fig. 4. Probe patterncar. Fig. 5. Three-compartment, trough- or door-type hopper car. Sampling AACC Method 64-70A Page 4 of 6 Manual Sampling of Wheat and Other Whole Grains (continued) Use of pelican. See Note 1. 1 Bulk grain being loaded into containers (cars, trucks, barges, or ships) can be sampled by swinging or pulling Pelican through falling stream of grain as it leaves loading spout. The number of times Pelican should be swung varies according to type of container and size of grain stream. Each swing is called a cut. 2. Take one cut approximately every 500 bushels (176 hectoliters). Cuts should be made at random intervals in the following manner: a. ensure loading spout is positioned so Pelican can be swing through entire stream; b. hold pole firmly so that pouch is back of falling stream; c. swing completely through entire stream in one continuous motion; d. compare each cut for uniformity of kind, quality, and condition. See Fig. 7. Use of Ellis cup. See Note 2. 1. Bulk grain being loaded or unloaded from containers (cars, trucks, wagons, barges, ships) can be sampled by inserting Ellis cup into grain stream as it moves on conveyor belt. The number of times Ellis cup is inserted varies according to type of container and size of grain stream. Three cupfuls is called a set. Fig. 7. Cutting stream. Fig. 6. Three-compartment, 10-hatch-type hopper car. Sampling AACC Method 64-70A Page 5 of 6 Manual Sampling of Wheat and Other Whole Grains (continued) 2. Take one set approximately every 500 bushels (176 hectoliters). Draw sets at random intervals as follows: a. grasp cup firmly in both hands and stand as close as possible to point where grain is delivered to conveyor belt; b. insert heel (curved portion) with opening facing in direction of flow in center of grain stream; c. push open end downward until cup is parallel with belt (see Fig. 8); d. draw two more cupfulsone at point halfway between center and right edge of stream and another at point halfway between center and left edge (see Fig. 9); e. compare each cup for uniformity of kind, quality, and condition. Sacked grain 1. With double-tube compartment probe of sufficient length to reach center of sacks, draw samples from as many individual sacks as will provide representa- tive sample of entire lot. 2. Sample number of sacks equivalent to square root of number in lot, but not less than 10, i.e., 10 from 100 or less, 15 from 225, 20 from 400 sacks, etc. Fig. 8. Inserting cup. Figures are reproduced from the Federal Grain Inspection Manual (Ref. 2). Fig. 9. Set of cups. Sampling AACC Method 64-70A Page 6 of 6 Manual Sampling of Wheat and Other Whole Grains (continued) Select sacks to be samples according to their exposure, in ratio of 4 from most exposed, 3 from next less exposed, 2 from next, and 1 from least exposed portion of lot. See Method 64-60. Comparing uniformity 1. If after examination of separate probes, cuts with Pelican, or separate Ellis cups, no portion of grain is distinctly inferior, combine grain from probes, cuts, or cups and treat combined sample as average sample of grain involved. 2. If portion appears distinctly inferior in any manner, take separate samples of distinctly inferior portion and of remaining portion, or of each distinctly inferior portion. 3. Once sample for container has been obtained, Boerner Divider may be used to mix and subdivide bulk sample into representative portions for analysis. Notes 1. Pelicans are not recommended for sampling at high-throughput modern facilities because high velocity of grain exiting spouts makes their use hazardous. 2. Extreme caution is required when using Ellis cup because operator must stand very close to moving belt, and it requires strong effort to penetrate sample mass. References 1. Department of Agriculture. 1996. Official United States Standards for Grain, 7 CFR, Part 810. 2. Grain Inspection, Packers and Stockyards Administration (GIPSA)/Federal Grain Inspection Service (FGIS). 1995. Grain Inspection Handbook, Book 1, Grain Sampling. 3. GIPSA/FGIS. 1996. Equipment handbook, Chapter 7, Manual Sampling Devices.