Pressure leaf filter
Pressure leaf filter is liquid filtration systems consisting of 10 to 60 leaves that are stacked inside a vertical or horizontal vessel. The leaves are drainage systems that support a wire or textile cloth cover. Pressure leaf filters are mainly divided into vertical pressure leaf filters and horizontal pressure leaf filters.
vertical pressure leaf filter
vertical pressure leaf filter is liquid filtration system consisting of many leaf-shaped filter elements that are stacked inside a vertical vessel.
vertical pressure leaf filter has been specifically designed to provide a large filtration area which is made possible due to the shape of their filter leaf elements. These vertical pressure leaf filter systems produce high filtrate clarity after the clarification run. Different types of filter aids can be used in vertical pressure leaf filters to improve filtrate quality.
Horizontal pressure leaf filter
Horizontal Pressure Leaf Filter (shell retraction or bundle retraction) features horizontal pressure vessel, filter leaves, pneumatic vibrator assembly, bottom structure housing, hydraulic power pack for bonnet ring opening / closing and shell or bundle retraction.
The horizontal pressure leaf filter is an enclosed filtration system and can be fully automated. This filter produces a high filtrate clarity after the clarification run and is also suitable for all kinds of filter aids. The regeneration time between the filtration cycles is short. Horizontal pressure leaf filters can also be delivered as tandem units to save floor space. The pressure leaf filter itself has no rotating parts, keeping maintenance to a minimum. These advantages result in an economical filtration solution.
How is the cake discharged ?
In both vertical and horizontal filters the cake can be dried by steam/ hot air and then discharged from the bottom with the help of mechanical / pneumatic leaves vibrator. The whole operation of cake drying takes 30-45 min. and cake discharge takes 5-10 min. For wet cake discharge water spray nozzles are provided. In Horizontal Pressure Leaf Filter wet cake can also be discharged manually by scrapping. The shell is slided out with Hydraulic Mechanism keeping the leaves in fixed position.
How is the Leaf Constructed ?
Each leaf is made of 5-ply of SS wire mesh of different gauge wires. Two outer filtering mesh and three inner are only for support. Different outer filtering mesh is used for different fitleration process. The 5-ply wire mesh are held together by a tubular frame and made leak proof by machine rivetting. The quality of filtration and life of filter depends mainly on the quality of outer wire mesh and revetting. SEPARATECH ensure the quality by inspecting quality of wire mesh and each leaf. Old worn out and torn leaves can be repaired by only replacing the outer weave. Optionally we also provide cloth on the leaves for fine or special filtration.
Vertical pressure leaf filter working principle
The vertical pressure leaf filter is ideal for separating solid from liquid and mainly works on the principle of precoating and pressure. Precoating is done by a suitable filter aid of about 0.5-1% (supercell Hyflo, Bleaching earth, super flow, and so on) mixed with the liquid to be decanted.
Unfiltered liquid is pumped into the vertical pressure leaf filter, and the filter starts creating a precoating layer in filter leaves on both sides. Until the filter is full, this procedure will continue. Once a precoating layer is done, the process of pressure starts and develops a restriction against impurities. And Clean liquid flows from the bottom of the leaf. Once the process is done and the leaves get choked perfectly, the pressure rises . And the output flow almost stops here. After this, the pump is completely stopped, and steam pressure is applied from the apex to filter. The material and squeeze the cake further to remove the liquid. Thus, all the leaves are mounted in the same manifold. And leaves start getting choked from both sides by impurities creating a cake that is in wet form.
The whole process of dry cake takes around 40-45minutes and the cake discharges within 5-10 minutes. It is dried by hot air and discharged from the bottom with the help of a pneumatic leaves vibrator.
Horizontal pressure leaf filter working principle
Leaf Filters are ideal for solid-liquid separation & work on principle of precoating & pressure.
Pre-coating is done with the help of suitable filter aid about 0.5 to 1% (Bleaching earth, diatomite, activated carbon, etc.) mixed with the liquid to be filtered. Unfiltered liquid is pumped into the filter vessel. Initially the filter aid starts forming a precoat layer on both sides of the filter leaves, until then cloudy material comes out of the filter. Once the layer is formed, pressure starts developing, restricting the impurities. Clear liquid flows from both sides into the leaves (filter elements), flows along the tubular channel & gets discharged from bottom of the leaf. All the leaves are mounted on a common manifold. The leaves start getting choked on both the sides by impurities forming cake, which is in wet from. Once the leaves get choked completely, the pressure rises to 3 kg/cm2 & the output flow almost stops. This means the batch size is reached. The pump is stopped & steam / air pressure is applied from the top (without dropping the filter pressure) to filter the material around the leaves held up in the tank & to squeeze the cake further & reduce the liquid retention in it. The holdup unfiltered liquid in the bottom portion is taken back.
Why SEPARATECH ?
SEPARATECH is the pioneer manufacturer of Pressure Leaf Filters in China since past 30 years. Our motto is to see a delighted customer and we try to achieve the same by producting world-class quality services. Our quality and services are justified by our exhaustive client list of hundreds delighted customers.
Amine: MEA, DEA, TEG
Catalyst Fines Removal
50% Sodium Hydroxide
Merrill Crowe Gold Recovery (Clarifiers)
Pregnant Liquor (Solutions) – Copper, Nickel,
Zinc, Molybdenum, Lead, Indium, Cobalt
Carbon Fines Removal
H2SO4, HCL, Nitric, Phosphoric,
Brine KCL, NaCl, Chlorate, Brine Muds
Dark, light, or bright sulfur
|model||filter area m2||no. of leaves||leaf spacing mm||height m||height mm||vessel vol. L||weight Kg|
|model||filter area m2||no. of leaves||leaf spacing||height mm||height mm||vessel vol. L||floor area occupied mm|
What are the advantages of pressure leaf filter?
= High yield low product losses
= Large filtration area – small footprint (high headroom)
= No filter cloth – no washing or cloth replacements
= Totally enclosed operation – no contact with air/moisture
= Positive pressure – no vacuum or lowered pressures necessary
= Wet or dry cake discharge
= Possible extraction of the filter cake within the filter
= Easy to automate – operation with minimum labour
= Fast and effective cleaning without manual interference.
= Mechanically simple
= Easy access to the filter leaves for maintenance or extra leaf cleaning
= Intensive cleaning of filter medium is possible
= Improved housekeeping
= Steam heating optional
Advantage of Pressure Leaf Filter over plate & frame filter ?
= Stainless steel filter elements, hence no repetitive cost, washing and maintenance of filter cloth.
= Automatic cake discharge in very short time without opening the filter from top, hence large saving in labor and time.
= Very low % of unfiltered liquid retention in cake.
= Closed & pressurized operating system hence no spillage & loss of liquid, which helps in handling volatile / inflammable liquids & clean working environment. Entire filtration cycle with cake discharge can be completed without even opening the filter from top.
= Compact & light hence large saving in floor area & supporting structures.
= Pressure leaf filter can be completely automated with no human intervention. = Pressure leaf filter can be used for getting filtered liquids as well as cake.