Introduction of Glass Fiber Extraction Thimbles
The glass fiber extraction thimbles are made of high-grade special ultra-fine glass wool and carefully processed by a special process. It is a high-efficiency filter device that collects harmful substances such as smoke, acid mist, and beryllium substitutes. Glass fiber extraction thimbles have the advantages of high-temperature resistance, low weight loss, high efficiency, and good strength.
Temperature resistance: can withstand below 600 ℃. Resistance: 14-20mmHg. Efficiency: 99.9999% (for dust particles with a particle size ≥ 0.3 ч). Weight loss: 0.2%. The current extraction thimbles are all glass fiber (applicable below 400 degrees).
The weight must be weighed before boiler dust sampling. In this process, it is best to dry and weigh in small batches. Because if it is a large batch, the opening, and closing of the dryer cover during the weighing process will inevitably make it absorb moisture, which will increase the blank value and cause the measurement result to be below.
Generally, there are two areas of the test hole that are not punched. One is on the horizontal pipe, in front of the base of the vertical chimney, and the other is on the vertical chimney. When the cross-sectional area of the flue is constant, it is considered that the location of the test hole is the same everywhere.
Because after the flue gas passes through the dust collector, the remaining part is only a part of the particulate smoke and the cold rail coil, so in the case of constant airflow, it generally cannot be completely settled.
For example, during a monitoring process, the glass screen printing machine, due to the opening of the plug, vibrated a part of the iron filings. During the test process, I found that there were some iron filings in the extraction thimbles. Just imagine that the iron filings cannot be settled, not to mention the small Where’s the smoke? Therefore, when the cross-sectional area of the flue remains unchanged, the location of the test hole has little effect on the test result.
Of course, if there is a significant change in the cross-sectional area of the flue after the dust collector, it is better to punch the test hole at the end where the cross-sectional area of the flue becomes larger because this can make use of the larger cross-sectional area of the flue and slower airflow. Precipitating a part of smoke and dust, makes the test result smaller.
What are the operating conditions of the glass fiber extraction thimbles?
Due to the characteristics of glass fiber, the following points must be paid attention to when using it. Before use, check that the two sampling heads are slightly blocked, and slightly hooped, whether the taper is the same, matching, and whether the clearance is appropriate. When the extraction thimbles are loaded and unloaded, it is not affected by the force of tearing, shearing, etc., so that the extraction thimbles’ mouth is not broken.
If the glass fiber extraction thimbles are found to have voids, cracks, or uneven thickness, they cannot be used to avoid being blown by the airflow and causing sampling failure. It should be used within the specified temperature range to ensure that the extraction thimbles work under sufficient strength.
According to reports, when the glass fiber is heated to above 200°C and then cooled, its strength begins to drop continuously. After the fiber is heated to 510°C and cooled, its strength only maintains 35% of its original strength. The fiber can maintain high strength when heated, but after cooling, its strength is greatly reduced.
Glass fiber extraction thimbles have been widely used in China since it was put into production in 1974. Due to the use of glass fiber extraction thimbles, my country’s smoke and dust detection work has been greatly improved.