The principle of diatomaceous earth filtration
Wines and beverages filtered with diatomaceous earth have the same flavor, are non-toxic, have no suspended or precipitated substances, are clear and transparent, have high filtration, occupy a small area, are lightweight, and are easy to move. The main control parameters are shell material, shell working pressure, diameter, additive dosage, and backwash strength.
The thickness of the filter membrane is usually 2-3mm, and the particle size of diatomaceous earth is 1-10 μ M. After filtration, often use water, compressed air, or both for backwashing. The advantages of doorless filtration are good treatment efficiency, less flushing water (less than 1% of production water), and small footprint (less than 10% of ordinary sand filter area). Compared with the old cotton cake filter, it has obvious advantages: energy saving of 92%, wine loss of 90%, equipment cost saving of 2/3, and production workers reducing by 3/4. So what is the principle behind its application?
The principle of diatomaceous earth filtration is to filter the liquid. Under the action of pump pressure, it enters the collection chamber through pre coating. Particles and polymers are intercepted in the pre coating, and the clarified liquid enters the collection chamber and flows out of the container through the central axis. The filter consists of a filter screen, a support screen, and an outer frame. Each filter element is a tube with holes as the skeleton, wrapped in metal wire and coated with diatomaceous earth coating on the surface. The filter element is fixed on the diaphragm, and the upper and lower parts of the diaphragm are the raw water chamber and the purified water chamber. The entire filtration cycle is divided into three steps: membrane laying, filtration, and backwashing.
Low cost of diatomaceous earth filtration: water consumption: backwashing water consumption is 1/10 of that of sand filters; Power consumption: The total power load of the A-1 reversible machine room is only about 3/5 of the total power load of the traditional sand cylinder filtration system machine room; Dosage: During filtration, it should be added to the A-1 type machine room, with a dosage of 0.2kg per square meter of filtration area per filtration cycle.
In the diatomaceous earth filtration method, diatomaceous earth itself has many natural small pores, and the irregular pores in the filter layer are longer and densely distributed throughout the entire cake layer, which can adsorb and accommodate more fine particles, thereby improving the quality of filtration. Filtering consists of two parts: screening and adsorption. In operation, diatomaceous earth is divided into a pre coating and a filter layer that adsorbs onto the filter cloth outside the filter, forming an incompressible filter cake layer with countless intricate and intersecting micro pores. During filtration, large impurities in the filtrate are trapped on the outer surface of the filter cake layer due to the inability to pass through relatively small filter pores, which is called the screening process. Fine particles enter the filter cake layer and are adsorbed and intercepted in the curved and intricate pores, which is called the adsorption process. In order to obtain a clear permeate solution. When the filtration pressure of the filter increases, it indicates that some of the filter holes in the filter layer have been blocked. At this time, a new filter layer is formed by adding diatomaceous earth to the filter machine to continue the filtration. When most of the pores in the filter cake layer are blocked and the filtration rate decreases, remove the filter cake, pre coat a new filter cake layer, and then filter. When observing the filtration of filter cakes divided into pre coated and filter layers, it can be observed that the vast majority of impurities are filtered out by sieving and are trapped outside the filter pores, with very few adsorbed impurities inside the pores.