This standard specifies the conditions, test equipment, test steps and methods for the determination of the suspension velocity of forage seeds. This standard is applicable to forage seeds, as well as to the determination of the suspension velocity of crop seeds, flowers, trees and other seeds. JB/T 7290-1994 Method for determination of suspension velocity of forage seeds JB/T7290-1994 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T 7290-1994
Method for Determining the Suspension Velocity of Forage Seeds
Published on July 18, 1994
Ministry of Machinery Industry of the People's Republic of China
Implementation on July 1, 1995
Mechanical Industry Standard of the People's Republic of China
Method for Determining the Suspension Velocity of Forage Seeds
1 Subject Content and Scope of Application
This standard specifies the determination conditions, test equipment, test steps and methods for the suspension velocity of forage seeds. JB/T7290-1994bZxz.net
This standard applies to forage seeds, as well as to the determination of the suspension velocity of crop seeds, flowers, trees, etc. Cited standards
GB2930
GB3543
GB4404
GB5262
GB6141
GB6142
GB6143
GB8079
3 Test conditions
3.1 Test site
Procedure for inspection of forage seeds
Procedure for inspection of crop seeds
Grain seeds
General provisions for test conditions of agricultural machineryQuality grading of seeds of main cultivated forage grasses in LeguminosaeQuality grading of seeds of main cultivated forage grasses in GramineaeQuality grading of seeds of Artemisia sphaerocephala and Kochia scoparia
Vegetable seeds
3.1.1 The test should be carried out indoors. The test equipment should be placed on a flat, solid concrete floor, with its top at least 2m away from the roof.
The air inlet of the test equipment should be cleaned and there should be no obstacles that block or affect the stability of the air flow. 3.1.3 Before the test, place a hygrometer and a barometer 3m away from the equipment to measure the relative humidity, air temperature and atmospheric pressure of the air around the test site. The measurement results are recorded in Table 2. 3.2 Preparation of test materials
Materials for testing. The quality of forage seeds should be uniform. The purity should reach level 3 or above as specified in GB6141~6143. 3.2.1
Crop seed purity: Grain seeds should reach level 3 or above as specified in GB4404; vegetable seeds should reach level 3 or above as specified in GB8079.
3.2.2 The moisture content of seeds for testing: forage seeds should comply with the provisions of GB6141~6143; crop seeds should comply with the provisions of GB4404 and GB8079.
3.2.3 The number of seeds for determination: for those with dry grain weight below 5g, the sampling weight shall be not less than 10g; for those with thousand-grain weight above 5g, the sampling weight shall be not less than 15g.
3.2.4 Before the test, the relevant characteristics of the seeds for determination shall be initially measured and the results shall be recorded in Table 1. 3.2.4.1 The determination of purity, moisture content and dry grain weight shall be carried out in accordance with the provisions of Article 4.7.8 of GB2930 for forage seeds and in accordance with the provisions of Articles 4.2, 4.6 and 4.7 of GB3543 for crop seeds. Approved by the Ministry of Machinery Industry on July 18, 1994
Implementation on July 1, 1995
JB/T7290—1994
3.2.4.2 The determination of bulk density shall be carried out in accordance with the provisions of Article 7.1 of GB5262. 3.3 Test equipment and instruments
3.3.1 Test equipment
The recommended test equipment is a straight tube air suction suspension velocity test bench, the structure of which is shown in Figure 1. The test equipment should meet the following requirements:
a. The air volume (wind speed) should be steplessly adjustable, and the adjustment range should meet the test requirements for small and large seeds; b. The observation section should be able to clearly observe the suspension state of the material; c. The dynamic pressure measurement points should be selected using the equal area ring method, with no less than 6 measurement points; d. The suspension velocity value in the pipeline should be calculated using the velocity coefficient correction method. 11-
Figure 1 Straight-tube airflow critical velocity test bench
1—inlet collector; 2—lower rectifier grid; 3—rectifier net; 4—contraction section; 5—seed net; 6—seed opening; 7—observation section; 8—test section; 9—transition section; 10—upper rectifier grid; 11—fan; 12—test hole; 13—pitot tube; 14—micromanometer Test equipment and tools
Testing instruments and meters should be within the calibration cycle. The instruments, meters and tools used are shown in Appendix A (reference). 3.3.3 Preparation of test equipment
3.3.3.1 Before the test, the tightness and sealing of each sealing part of the equipment should be checked according to the requirements of the instruction manual. If the sealing is found to be loose, the sealing gasket should be replaced and the connecting bolts should be tightened again to keep the equipment in good condition. 3.3.3.2 Check whether the power supply circuit is connected correctly and whether the direction of the fan is consistent with the direction marked on the shell. If there is any error, it should be corrected immediately. 3.3.3.3 Before the test, the observation section of the test bench should be wiped clean. There should be no dust, dirt, light impurities and other defects that affect the observation of the floating condition of the seeds.
The seed net should not be blocked or contaminated by seeds or other foreign objects. The seed opening door should be opened freely and closed tightly. 2
4 Test steps and methods
JB/T7290—1994
4.1 Open the seed opening and clean the seeds or other substances remaining on the seed net. 4.2 Insert the pitot tube into the test hole and make the elbow part face the windward side. 4.3 Place the micromanometer on the platform, and use a soft rubber hose to connect the micromanometer and the pitot tube according to the requirements of the instruction manual, and then adjust the micromanometer to the working state.
4.4 In order to accurately reflect the speed difference caused by the different shapes, particle sizes, thousand-grain weights, etc. of each batch of seeds, a segmented test method is adopted, that is, each batch of seeds is divided into three sections according to light, medium and heavy, and six points are measured in each section. The average values ​​of dynamic pressure and suspension speed of each section are first calculated, and then the suspension speed value of each batch of seeds is calculated. The measured results are recorded in Table 2. 4.5 Measurement point location: The circular section is divided into several circular rings with equal areas, and each circular ring is divided into two parts with equal areas. The measurement point is placed on the dividing line of the two parts, as shown in Figure 2. Figure 2 Schematic diagram of measurement point location
4.6 Measurement steps
4.6.1 Put 10g of seeds (if the thousand-grain weight is more than 5g, put 15g of seeds), spread it flat on the seed placement net, and close the switch door. 4.6.2 Start the fan and adjust the speed slightly. At this time, some seeds will float up and suspend in the middle of the observation section. When observed from the organic glass observation section, about 1/3 of the seeds on the seed net will float up. The wind speed is fixed. This is the first section. 4.6.3 After measuring the dynamic pressure value of each point in this section, open the seed opening switch door, quickly insert the material receiving box, turn off the fan, and the floating material will fall into the box. Take it out and weigh it to calculate the weight proportion of the seeds in the first section. 4.6.4 Adjust the speed higher, and another part of the seeds will float up and suspend in the middle of the observation section. The number is about 1/2 of the remaining seeds. This is the second section. After measuring the dynamic pressure value of each point in the same way, take it out and weigh it to calculate the proportion. Then measure the third section in this way. 4.6.5 After measuring the dynamic pressure value of each point, calculate the suspension speed value according to the following formula. U=Ky?
Where: —Suspension velocity of the material to be measured, m/s; K--Ratio of average velocity to maximum velocity, generally K=0.84; 3
JB/T7290-1994
Velocity distribution coefficient, generally =0.97;
g—Gravity acceleration, g=9.8m/s;
h—Manometer reading (mm water column, 1 mm water column = 9.8Pa); Air density, when the temperature is 20℃ and the relative humidity of the air is 50%, take e. =1.2kg/m. Q
5Test report
After the measurement, organize, summarize and analyze the measurement data and write a test report. 5.1
5.2 Test The content of the test report should include: a. Overview: state the test purpose, machine name, model, research and development unit, test time and location, etc.; b. Introduction to the test machine: state the machine's structural characteristics, working principle and process; c. Test results and analysis;
d.Attached are relevant test data, charts, photos, etc. Table 1
Test material test record
Machine name:
Test location:
Material name
Moisture content
Thousand-grain weight
Determination:
Record:
Test date:
Providing unit:
Review:
Equipment name:
Average temperature:
Material name
Sample weight g
Weight of each section| |tt||Weight percentage of each section
Dynamic pressure value Pa
(mm water column)
Suspension speed
Determination:
Average of three sections
JB/T7290—1994
Table 2 Test measurement record
Test location:
Atmospheric pressure:
Record:
Average temperature:
Test date:
Review:
JB/T 7290-1994
JB/T7290-1994
Test instruments, meters and tools
(reference)
Test instruments,:
Meters and tools are shown in Table A1.
Pitot tube
Compensated micromanometer
Regulated power supply
Voltage regulator
Ammeter
Voltmeter
Hygrometer
Barometer
Sample divider
Sampler,
Sampling tray, sample bag, etc.
Bulk density meter
Drying box and cooler
Tweezers, bone spoon, layer
Additional instructions:
?8×300mm
YJB150 type
614-A,W (1kVA)
TDG-1/250
0-250V
Sensitivity 0.001g
This standard is proposed and managed by the Hohhot Animal Husbandry Machinery Research Institute of the Ministry of Machinery Industry. This standard is drafted by the Hohhot Animal Husbandry Machinery Research Institute. The main drafter of this standard is Mi Cailin.
1 each
People's Republic of China
Mechanical Industry Standard
Method for Determination of Suspension Velocity of Forage Seeds
JB/T72901994
Published and issued by the China Academy of Mechanical Science
Printed by the China Academy of Mechanical Science
(No. 2 Shouti South Road, Beijing
Format 880×1230
Postal Code 100044)
1/16 Printing Sheet 5/8
Word Count 12.000
First Edition in May 1995
First Printing in May 1995
Price 8.00 Yuan
Print Quantity 1-200
Mechanical Industry Standard Service Network: http://www.JB.ac.cn6610
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