Now, the market has higher and higher requirements for product quality. It no longer only meets the internal quality of diammonium phosphate but also has higher requirements for external quality (particle size, color, etc.). At present, the diammonium phosphate sold on the market has various colors such as green, yellow, brown, black, natural color, etc. The traditional colorimetric measurement method is the visual method. critical result. This method is susceptible to factors such as light source, measured object, location, and observer. Changes in any one of these factors may lead to changes in the judgment results. If the color of the product is visually controlled, the color of the same batch of products may be inconsistent or different. There are differences in the color of the batches, causing controversy. For this reason, it was decided to use a colorimeter to test the color of DAP products. The actual use shows that it has the advantages of simple operation, rapidity, accuracy, safety and environmental protection, and is an accurate and reliable chromaticity detection device.
The working principle of colorimeter
A colorimeter is an optical measuring instrument that simulates the human eye’s perception of red, green, and blue light, and can analyze the chromaticity (hue, lightness, saturation) of the measured object. The working principle of the colorimeters is that the pulsed xenon lamp emits a light source to illuminate the sample. After reflection to the grating, the optical signal is converted into an electrical signal, and finally converted into a digital signal; the calculation process is from the spectral energy of the light source, the reflectance of the sample (Transmittance), the instrument stimulates the observer, the integral value of the coefficient obtains the corresponding X, Y, Z tristimulus values, and then the chromaticity scale is obtained by conversion.
The experiment
The main instruments: colorimeter; Calibration plate; glass sample cup, (diameter6. 35 cm).
The experiment methods:
starting up
Turn on the power of the caliber 8mm portable colorimeter, at this time the display shows the operation menu. Menu contents include standardizing, select setup, instrument setup, standby mode. Press the up or down arrow key to select a menu option when the menu to be selected is presented. When highlighted, press the test key to select the menu.
setting up
The mode switch in the lower right corner of the instrument is divided into measurement mode (lightning icon) and setting mode (question mark icon). It is set to measurement mode during operation.
The revise
Place the instrument’s highlighted cursor on the menu option, press the test key on the control panel, and the instrument will enter the calibration interface. When “Please read the black glass sheet” appears at the bottom of the instrument display screen, place the black calibration plate at the measuring position on the upper part of the instrument, and then press the test button; when “Please read the white enamel tile” appears at the bottom of the instrument display screen, place the white calibration plate at the measuring position on the upper part of the instrument, and then press the test key; when the display shows “Lab”, the calibration of the instrument is completed, and the test interface is automatically entered.
The measure
When “Please read the standard” appears at the bottom of the display, but the sample into the glass sample cup and the sample volume is half of the glass sample cup; Hold the sample cup and press the measurement key to complete the measurement. At this time, the display shows the values of L, a, and b, and “Please read the sample” appears at the bottom of the display. Record the L, a, and b values of the sample, and the sample measurement is completed. During operation, samples can be continuously measured.
In conclusion
The results show that the colorimeter is used to measure the color of DAP, which eliminates the uncertain factors of light sources, objects, and people, improves the accuracy of analysis, and provides a digital basis for the determination of DAP color, and the production control is relatively stable. Improve product market competitiveness. These colorimeters are simple and fast to analyze, can measure multiple samples continuously, and can be widely used in the determination of diammonium phosphate chromaticity.