In fact, customers have been asking how often the filter sand tank needs to be backwashed. In fact, there is no fixed formula for the so-called backwash cycle. Just like eating, you can eat when you are hungry. Moreover, the filter sand tank is widely used. For different industries, the number of impurities and other factors are different, and the backwash cycle is also different. The following analysis of several factors affecting the backwash cycle:
1. Different places of application. For example, some customers take the filter sand tank to filter the impurities in the mountain spring water. In this case, the mountain spring water is generally clear, so it is possible to backwash once every ten and a half days. But some customers are used to filter impurities in urban sewage, which may need to be backwashed once a day.
2. The selection of sand cylinder is different. We can see that the filter sand tanks sold by Espa have a parameter of design flow. But this parameter can only be used as a reference in application. Because the flow of filter sand tank will vary with the flow of water pump, sand thickness, sand size, filter area and other factors. In theory, the larger the sand tank is, the larger the filtration area is, and the smaller the resistance of water flow is under the same suspended solids content and flow rate. The higher the filtering accuracy. The shorter the backwash cycle.
3. The subjective judgment of customers is different. Because some customers have subjective differences in the determination of the sewage after backwashing. So the backwash cycle also varies with his judgment.
Solution: a cycle can be determined according to the turbidity of the previous backwash sewage and the reading of the pressure gauge. For example, in normal filtration, the pressure gauge counts 0.1MPa. When the pressure gauge reads 0.2MPa, we backwash once and find that the discharged sewage is not so dirty. Then we can understand that the next backwashing time can be extended. Several times, each time we record this time interval. A proper backwash cycle will be obtained. In this way, a good balance can be achieved between not affecting pollution discharge and not paying more labor.