Matters Needing Attention During the Use of Glass Fiber Extraction Thimbles
Introduction of glass fiber extraction thimbles
The ultra-fine glass fiber extraction thimbles are made of 100% alkali-free glass fiber and processed at high temperatures, free of adhesives and chemically inert. It can collect fine and submicron particles. It is a filtering device for capturing pollution source particles, acid mist, aerosol, beryllium compounds, and so on, with high-efficiency and high-quality. It has the advantages of high-temperature resistance, small weight loss, high collection efficiency, high strength, etc., and can be widely used in the collection of samples of pollution source particles and metal compounds in various situations.
In the monitoring of air pollution, the monitoring of smoke emission concentration is a relatively conventional monitoring project and a relatively mature monitoring project. Whether it is monitoring the location of sampling points or monitoring equipment, there are clear quality control and management standards. In daily monitoring, the sampling extraction thimble is mainly glass fiber.
The glass fiber extraction thimbles are used to sample atmospheric particles, and the relatively stable weight of the extraction thimble becomes the key to the success of the experiment. For this, there are two key factors:
If there is glue, the volatilization of the glue component during heating will cause weight loss, so it must be 100% glue-free;
The extraction thimble must be brittle if there is no glue, and debris is likely to fall off during the experiment, so it must have a higher strength of adsorption.
The above two contradictions have also become key considerations in the manufacturing process. The glass fiber extraction thimble produced by HAWACH has solved the above problems.
1. The extraction thimbles should be protected from squeezing and moisture during transportation and storage;
2. Before using the extraction thimbles, use a soft bristle brush and ear washing ball to dust off the outside and fiber debris;
3. The dried extraction thimbles is placed in a 105℃desiccator, cooled for 30 minutes, then weighed on a 1/10000 balance, and write down the weight;
4. Before use, check the two slightly clogged and hoop of the sampling head, whether the taper is the same and matching, and whether the gap is appropriate. When the extraction thimble is loaded and unloaded, it is not affected by tearing, shearing and other forces, so that theextraction thimble mouth is not broken;
5. If the extraction thimble is found to have gaps, cracks or uneven thickness, it can not be used, so as to avoid sampling failure caused by airflow;
6. It is to be used within the specified temperature range, to ensure that the extraction thimble works under sufficient strength. When the glass fiber is heated above 200℃and then cooled, its strength begins to decrease continuously. After the fiber is heated to 510℃and cooled, the strength remains only 35% of the original. The fiber can maintain high strength when heated, but after cooling, its strength is greatly reduced;
7. After sampling, gently remove the extraction thimble from the sampler, place it in a 100℃ oven for 30 minutes, and then place it in a desiccator for 30 minutes to weigh and record the weight;
8. For the collection of finer particles such as asphalt smoke, you can choose to add a heavy rubber-free extraction thimble.