Diatomaceous Earth Filter

Diatomaceous earth filter is a filter device that uses the fineness and porosity of diatomite particles to remove impurities such as suspended particles and colloids in liquids, it uses diatomaceous earth as filter aid, widely used for liquid clarification and filtration. The different designs of filter core components, it can be divided into the plate and frame type, disc type, and candle type. Today we will give a brief introduction to these filters and their difference.

The disc type diatomaceous earth filter is the most common filter in these types, the filter media can be selected from diatomaceous earth, perlite powder and activated carbon. The filtered liquid is not only of good internal quality, but also more in line with the requirements in appearance.

In a closed stainless steel container(tank), a stainless steel filter disc is placed horizontally from bottom to top. The upper layer of the disc is a stainless steel filter screen, the lower layer is a stainless steel support plate, and the middle is a liquid collection chamber. During filtration, diatomite pre-coating is performed first, so that a layer of diatomite coating is formed on the disc. The liquid to be filtered enters the collection chamber through the pre-coating under the action of the pump pressure, and the particles and macromolecules are intercepted in the pre-soil layer, the clear liquid in the collection chamber, passes through the shaft, and flows out of the container.

This machine is mainly used for filtering syrup(≤65Brix).  After pre-coating and adding a filtering agent during the filtering process, the syrup turbidity can reach below 0.4EBC. In addition to filtering syrup, the disc-type diatomaceous earth filter can also be used for clarifying and filtering liquid products such as beer, wine, rice wine, liquor, fruit juice, gelatin, soy sauce and vinegar, as well as medicine and chemical products.

1) High filtration efficiency and less stable filtration quality;

2) Compact structure, complete configuration, convenient operation, flexible movement, easy maintenance, safe and reliable;

3) The conical filter disc used by this machine is placed horizontally, which can realize self-support, is firm and reliable, not easy to deform, and has a long service life;

4) The filtration of liquid is carried out in a series of fully enclosed high-quality SUS304 stainless steel polishing containers and sanitary pipelines; it is beneficial to meet the sanitary requirements of safe filtration and cleaning of liquids;

5) The rotary transmission of the filter disc adopts the transmission of motor + hydraulic coupling + belt deceleration, which not only has the function of reliable fault overload safety protection, but also can effectively prolong the service life of the filter disc wire mesh;

6) Intermittent filtration is performed, but the filter does not fall off, which is good for production preparation.

• The disc is in a horizontal state, and the pressure fluctuation has little effect on the filter layer;
• During cleaning, backflush cleaning from the hollow shaft, drive the filter disc to rotate, and remove the waste diatomite;
• The filtration operation and cleaning are automated, the sealing is good, and the head and tail of the wine can be compressed with CO2;
• If the filtration process is interrupted for some reason, the diatomaceous earth filter layer will not be damaged, and the filtration can be continued after recovery.

• Diatomite can only be deposited on the filter screen of the filter disc, and the effective area is small;
• The space height requirements of vertical cylindrical tanks are high;
• High precision is required for the central axis to ensure that the filter disc is flat and even.

The candle-type diatomite filter is an automatic pressure filter device. The filter element is a candle-type filter element. It is mainly composed of a cylinder, filter element, filter cloth, filter aid, computer control system and accessories. Other auxiliary equipment includes For air compressors, pressure sensors, etc., the cylinder and filter element are mainly made of stainless steel (304/316L), and the filter cloth is mainly made of PP (polypropylene), PE (polyester), PPS (polyphenylene sulfide), PTFE (polytetrafluoroethylene), nylon fiber, etc., filter aids are mainly include activated carbon, diatomaceous earth, etc.

The cylinder of the candle-type diatomite filter is equipped with one or more filter elements, and the filter element is covered with a special filter cloth selected according to the characteristics of the raw material liquid (some special raw material liquids need to be added with filter aids, such as activated carbon, diatomite, etc.)

When the liquid passes through the filter cloth, the solid substances in the liquid will gradually accumulate on the surface of the filter cloth. When these solid substances reach a certain thickness, the so-called “filter cake layer” is formed. Because the gap between the particles in the filter cake layer is very small, the escape of particulate impurities in the liquid is blocked, so that the filtrate becomes clear and the filtration effect required for production is achieved.

High fructose syrup filtration; decarbonization and decolorization filtration of citric acid, malic acid, sulfuric acid, and lactic acid; lycopene filtration; yeast, soybean protein precision filtration; various fruit juice precision filtration; soy sauce, vinegar filtration; wine, beverage precision filtration; crude oil, edible oil, blending oil precision filtration.

1. The filtered liquid has high turbidity and is the first choice for improving product turbidity.
2. It can filter out fine particles and bacteria of 0.1 micron and 0.089 micron, and can include fission products.
3. The filter capacity is from 200L to 50T, filter area is from 0.15-30m^2.

• The filter layer is laid on the steel support ring, which has a relatively large filtering area and high filtering efficiency;
• During filtration, as the thickness of the diatomite filter layer increases, the filtration area increases accordingly, so that the filtration volume is relatively stable;
• There is a large backwash pressure, which can clean each candlestick well;
• Simple operation and easy automation.

• Diatomite is attached to the vertical cylindrical surface and is greatly affected by pressure fluctuations, so the filtration process should not be stopped;
• Candlestick height requirements are high;
• It is not possible to squeeze the head and tail of the wine with CO2;
• The cost of the filter element is high, and the soil leakage of the filter element is not easy to find.

The precision plate and frame filter is made of 1Crl8Ni 9Ti or 316L high-quality stainless steel, which is corrosion-resistant and durable. Because the filter plate of this machine adopts a threaded structure, different filter materials can be replaced according to the requirements of different production processes (preliminary filtration, semi-fine filtration, and fine filtration) of the filtrate. Users can also reduce or increase the filter frame and filter plate according to the production flow to make it suitable for production needs. All sealing parts of the machine are equipped with sealing rings (milk white silicone rubber sealing ring, non-toxic and high-temperature resistance), no leakage and good sealing performance.

This machine can also be specially equipped with an automatic return channel according to the needs of users. After the pump stops rotating, open the return valve, and all the deposited materials will automatically return and discharge. When filtering high-viscosity liquid, it can make the liquid unobstructed, and can make various impurities flow back and discharge automatically. At the same time, use clean water to backflush the filter material from the return channel for temporary cleaning. The pump and the input pipe of the machine are connected by a three-fold snap ring, which is firmly sealed and easy to disassemble and clean.

The suspension is pumped into each closed filter chamber of the filter machine. Under the action of pressure, the filtrate penetrates the filter layer and filter cloth, and is discharged through the filter cloth outlet, while the filter residue remains in the filter frame. Form a filter cake to achieve the purpose of solid-liquid separation.

The filter is widely used in beer, fruit wine, wine, concentrated juice, gelatin, alginate and other liquids that have been pre-filtered for fine filtration or sterilization filtration. Especially for health-care wine, the fine filter can effectively solve the problem of flocculent precipitation after passing through the diatomite filter and freezing treatment.

• The filtration is stable, the operation is easy to master, and the cost is low;
• The support plate is used as the pre-coating medium, the pre-coating is firmly attached, the sedimentation is uniform, the filtration performance is consistent, and the clarity of the wine is guaranteed;
• During the filtration process, the pressure fluctuation is small, the pre-coating is not easy to fall off;
• Low diatomite earth consumption.

• After a set of support plates is used for several filtration cycles, it needs to be cleaned and replaced, which increases the cost;
• It is labor-intensive to disassemble the plate and frame to discharge the waste diatomite;
• The edge of the cardboard is exposed outside the frame, which is prone to seepage or leakage of wine, and mold on the surface;
• After the filtration is interrupted, it is necessary to re-circulate to form a filter layer before performing the filtration operation.