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Johnson Screen For Diatomaceous filter


We are a manufacturer of metal filter elements, we can provide customized service of Johnson filter element (wedge wire filter) for diatomaceous filter manufacturers all over the world.

Diatomite filter: a filter device that uses diatomite as the main medium to remove suspended particles, colloids, and other impurities in swimming pool water by using the fineness and porosity of diatomite particles. Diatomite filter has high filtration precision and can filter out most bacteria and some viruses under normal working conditions.

Diatomite filter types and filter area calculation

Diatomaceous Earth wedge wire Filter

Diatomaceous Earth Wedge Wire Filter

Diatomaceous earth filter is a kind of water treatment and purification equipment mainly used in swimming pools. It has high-efficiency, stable, and safe water treatment, and purification technology.
So, what are the types of diatomaceous earth filter, how to calculate the filtering area? Let’s talk about it in detail below.

The calculation method of the diatomite filter filtration area

  • Make sure that the filtration accuracy is a 25-micron filtration ratio, such as 200 (filtration efficiency), and determine when to choose the filter material.
  • According to the given pressure drop of 0.05MPa, the flow pressure difference test of the filter material is carried out. Obtain the appropriate flow rate (L / min).
  • According to the obtained flow rate, divided by the area of the test filter material, the flow velocity (L / min.m2) is obtained.
  • According to the flow rate and the actual flow rate, determine the filtration area, flow rate/flow rate = filtration area.
  • According to the selected filter area and filter, material to determine the filter element structure, folding or cylindrical winding.

Types of diatomaceous earth filter

  • According to the type of filter unit: column type and plate type.
  • According to the use of the filter: integrated and independent.
  • According to the use of additives: reversible and renewable.
Johnson screen for Diatomaceous Earth Filter

Diatomaceous Earth Filter Element Package

1) Reversible diatomite filter
It is usually a plate type, and the diatomite membrane can be coated in both directions of the filter unit.
The water flow can be filtered from the positive direction, and it can also be filtered by switching to the reverse direction, saving the switching time of filtration, recoil, and coating. Thickness, filter speed from 2m / h-10m / h.

2) Renewable diatomite filter
It is usually column type, and the filter is tank type.
The cylindrical wedge wire filter unit is placed in the tank body. When the filter is shut down, the diatomite in the tank can be reused when it is turned on again, saving the water amount of diatomite and backwashing. The film is relatively thick and has a large amount of pollution.
[We mainly provide customized services for cylindrical wedge wire filter elements for diatomite filter manufacturers.]

Attention: the filter foundation shall be constructed in accordance with the design drawings. The foundation bolts of the stable equipment shall be firmly combined with the concrete foundation. The embedded holes shall be cleaned before pouring. The bolts shall not be skewed and the mechanical strength shall meet the requirements. The concrete foundation shall be equipped with a moisture-proof layer.

Working principle

wedge wire filter for Diatomaceous filter

Wedge Wire Filter Tube

During filtration, diatomite precoating is formed on the candle wedge wire filter element.
When the material passes through the diatomite filter layer attached to the surface of the candle filter element, the suspended solids, and colloidal particles are intercepted, and the clear liquid passes through the V-wire gap to achieve the purpose of filtration.

As the filtration time goes on, more and more impurities will be filtered off on the precoating, and the filtration channel (wedge wire gap) will be blocked.
Therefore, in the process of filtration, it is necessary to add a certain amount of diatomite of corresponding particle size to the filtered liquid entering the filter tank to maintain the normal filtration process.
In addition, if decolorization is needed during filtration, a certain proportion of activated carbon should be added.

Diatomaceous Earth [DE] Filtration Vs Activated Carbon Filter

The diatomite filter is to make the liquor clear, and the activated carbon filter is to absorb the high-grade esters and evil impurities in the liquor.
They are used for different purposes, so it is necessary to select appropriate filtering equipment according to specific needs.

Diatomaceous Earth Filter Backwash

The candle filter element of diatomaceous earth filtration is wedge wire filter cartridge, with continuous slotting structure and V-shaped wire structure, so that it is not blocked and the cleaning cost is low.

In the filtration stage, with the operation of the filter, the impurities in the filter material are retained by the diatomite pre-coating layer, so that the head loss of the filtered water through the filter membrane layer increases gradually. After the head loss reaches the set value, the filter shall be backwashed to remove the dirty diatomite.

  1. The backwashing method of the diatomite filter is the same as that of the sand filter. Water or air-water is used to feed into the filter from the opposite direction of water flow when filtering, and the diatomite pre-coated on the Johnson screen filter element is washed clean.
  2. The duration of backwashing is generally 1-3min.
  3. The working cycle of reversible diatomite filter is generally one day, that is to say, the filter needs to be back washed once a day, and must be washed clean.
    Because it works in two directions, i.e. the pre-coating and filtration work alternately. Therefore, when the pre-coating is reapplied, the residual diatomaceous earth that is not completely washed during the last cycle will be brought into the swimming pool by the filtered water because it enters the other side for pre-coating from the last filtered water. Therefore, special attention should be paid to the backwashing of the reversible diatomite filter.
  4. Backwash water discharge.
    The components of backwash drainage are complex, but the residual content of the main component diatomite should be calculated according to the water consumption of backwash.
    The backwash water of the filter can be used as the raw water of the building reclaimed water system.
    Deep lake water tanks can also be used to discharge backwash water into the tank for sedimentation and reuse of clean water. Diatomite sediment at the bottom of the tank can be used as plant fertilizer. Which method shall be adopted depends on the specific engineering situation.

Candle Type Diatomaceous Drum Filter Application Scope

Diatomite filter is suitable for clarification and filtration of fruit wine, white wine, health wine, wine, syrup, beverage, soy sauce, vinegar, biological, pharmaceutical, chemical, and other liquid products.

  1. Drinking water
  2. Beverage industry: fruit and vegetable juice, tea beverage, beer brewing, yellow wine, fruit wine, white wine, wine, etc
  3. Sugar industry: sucrose, fructose syrup, high fructose syrup, glucose syrup, beet sugar, honey, etc.
  4. Medical and pharmaceutical industry: antibiotics, vitamins, synthetic plasma, Chinese medicine extract, etc
  5. Condiments: vinegar, soy sauce, monosodium glutamate, cooking wine, etc.
  6. Chemical products: resin, inorganic acid, organic acid, alcohol, benzene, aldehyde, ether, etc.
  7. Aquarium, swimming pool.
  8. Others: gelatin, bone glue, seaweed glue, vegetable oil, starch, etc.

Johnson screen’s special v-wire structure enables it to work efficiently in a complex filtration environment, with a wide range of applications.

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