Feed mixer test for mixing uniformity and noise problems
Mixing uniformity and noise are two important indicators in the detection of feed mixers. There are many factors affecting the results of these two indicators, and it is easy to neglect, resulting in inaccurate measurement results. Netizens make a brief analysis of the factors that affect their determination. First, the mixing uniformity There are two methods for determining the uniformity of mixing, namely the methyl violet method and the precipitation method. The methyl violet method uses methyl violet as a tracer, and adds it together with the additive to the feed to be mixed. After the feed is mixed, the sample is taken therefrom, and then the methyl violet content in the sample is determined by colorimetry. As a basis for reflecting the uniformity of feed mixing. The methyl violet method is the most commonly used method for determining the mixing uniformity, and it is also the most accurate and reliable method. Only the factors affecting the mixing uniformity by the methyl violet method are analyzed. Test material The material shall be corn flour processed according to the second-class corn specified in GB1353. The geometric mean diameter of corn flour is not more than 1 mm, the geometric particle uniformity is not more than 2.5, and the water content is not more than 14%; in actual tests, these condition indexes are generally easily ignored, and these conditions will affect the measurement accuracy of the mixing uniformity. Because of the methyl violet method, each sample is 10g, and the content of methyl violet is only one hundred thousandth of the sample. If the particles are not uniform, it will affect the distribution of tiny parts in the feed. This leads to inaccuracies in the determination of the mixing uniformity. 2. Tracer methyl violet Methyl violet is used as a tracer, and the sensitivity is very high. The difference of the small amount has a great influence on the concentration of the filtrate, and the change of the concentration will affect the extinction value, thereby affecting the measurement result of the mixing uniformity. Due to the different degrees of methylation of different batches of methyl violet, the hue may vary, so in the test, the same batch must be used and thoroughly mixed. When the feed mixer is used to produce compound feed and concentrated feed, the methyl violet is ground and passed through a 0.1 mm standard round sieve. When the feed mixer is used to produce premixed feed, the methyl violet is ground through a 0.074 mm standard round sieve. The tracer must be weighed with a balance of 0.01 mg or more. The tracer dose of each batch of mixed test is one in 100,000 parts of the material. The tracer is preferably made of a paper having a relatively high density and a smooth surface, rather than being weighed and packaged with a rough paper to avoid the tracer error and affect the accuracy of the mixing uniformity. 3. Mixing time Generally, the longer the mixing time, the better the mixing uniformity, but this will reduce the productivity. Therefore, the mixing time must be according to the specifications specified in the instruction manual. The mixing time cannot be shortened or extended at will, and the mixing time of each test should be the same. 4. Sampling and sample dispensing After each batch of materials is mixed, the samples should be taken at equal intervals from the discharge port. The weight of each sample should be kept at 100-150g. Samples should be taken in the same way for each sample, and the time and number of repetitions should be consistent. 5. Precautions for sample handling Blank reagents must be taken from the same batch of corn flour. When the sample is analyzed with a Bessel flask, the stopper must be covered to prevent the evaporation of ethanol, resulting in an increase in the concentration of the solution, which affects the extinction value of the sample. When the extinction value of each filtrate is measured by a spectrophotometer, the same blanking agent is used for re-setting before each measurement to ensure the accurate value. Second, noise The noise measurement of the feed mixer is generally measured by a simple method, and it is often easy to ignore the influence of the test environment during the detection process. 1. Test environment requirements When measuring outdoors, the reflecting surface should be hard ground, concrete or asphalt floor; when measuring indoors, the reflecting surface is usually the ground plane in the room, allowing the use of wood or brick floor, the reflecting surface should be larger than the projection of the measuring surface. The sound absorption coefficient of the reflecting surface should be less than 0.1. If it is grass or snow, the measuring distance should be no more than 1m due to the large sound absorption coefficient. Except for the sound source being measured, other reflectors should not be placed inside the measurement surface. 2. Test environment identification In the field measurement, the outdoor or indoor measurement site should be identified first. The identification of the test environment is usually to determine the sound absorption A and the measured surface area S of the test site, and calculate the environmental correction value K2 by the following formula. Where, S--measure surface area, m2 A--test room sound absorption, m2 A=α·Sv Where α--average sound absorption coefficient Sv--the total surface area of ​​the test chamber, m2