Dew offers its customers the widest process experience and filter press choice from a single source.
The scope of supply includes plate and frame, chamber and membrane filter presses from size 250 x 250 up to 2450 x 2450 mm with filtration areas from 1 m˛ up to 2000 m˛ and maximum filtration pressures up to 60 bar, for manual or fully automatic operation - and for the different applications: municipal or industrial, food, ores, earths, chemicals, pigments, minerals - you name it, we have it.
We offer filter cake discharge equipment from simple cloth or plate shaking devices to tiltable frames to the third generation of high-tech patented filter cake scrapers. Each system has been tried and tested and can be retrofitted into existing systems. Customer and product specific requirements are met by optimum (sometimes tailor-made) adjustments.
Chamber Filter Presses
Chamber filter presses are reliable and robust in many different applications. The plate pack consists of uniform chamber plates with a recess of 15 - 50 mm to receive the filter cake. A chamber plate is a combination of a filter plate and two frames in once piece. The standard material for chamber plates is Polypropylene. Possible operating pressures: 6, 15 and 30 bar.
Membrane Filter Presses
Membrane filter plates are designed just like the previously described chamber plates. A flexible membrane is fixed to the support body. Materials for the membranes include Polypropylene, synthetic rubber (for example NBR, EPDM) or thermoplastic elastomer (TPE). Special materials such as PVDF are also available, during the initial phase of the filtration cycle, so-called “fill and filtration” the process is similar to the chamber filter press. After reaching a predefined pressure, usually around 4-10 bar, depending on the sludge characteristics, sludge feeding is stopped and the membranes slowly inflated, using either water or air as squeeze medium. The cake is hereby compressed and dewatered further. This process is continued until the filtrate flow reaches a preset minimum limit. Then the squeeze medium is relieved and the cake discharged.
Plate & Frame Filter Presses -Sheet Filters
The chambers of this type of filter press are formed by combining Polypropylene filter plates and frames. This creates chambers of 5 - 40 mm, depending on frame thickness. Plate and frame type filter presses are suitable for pre-coating filtration, which in the beverage industry, is used for clear filtration. Dew supplies plate and frame type filter presses for operating pressures up to 6 bar.
Belt Press Dewatering System
Sludge dewatering unit which can be applied through organic and inorganic sludges to achieve required results at least operating cost. The Belt Press can handle very lean sludges and for this an independent gravity drainage deck is provided to pre-thicken the sludge before it enters the main sections. Basically in the Belt Press, the sludge dewatering is achieved by bringing the sludge between the two moving belts which in turn moves on the varying sizes of rollers keeping belts under tension through hydraulic cylinder system which results in squeezing out the liquid trapped between the solids and withdrawn for auto belt tracking which makes the system operator friendly.The Belt Presses can be supplied in carbon steel or stainless steel Construction.
Main components of Belt Filter Press Dewatering System
Sludge Feed System
Delivers sludge to inlet box of Belt filter Press. Typically comprises of feed pumps and piping upto inlet of Belt Filter Press. Incorporates an on-line static mixer for thorough mixing of sludge and polymer.
Polymer Dosing System
Doses polymer solution on-line upstream of Static mixer. Typically comprises of polymer solution preparation tank with agitator, dosing pump(s) and piping upto dosing point.
Belt Wash Water System
Delivers washwater at the required flow rate and pressure to the wash water headers of Belt Filter Press. Typically comprises of a water source, wash water pumps and piping.
Dewatered Sludge Collection System
Serves to collect dewatered cake from Belt Filter Press. Typically comprises of a Discharge Chute / Belt Conveyor and a Collection trolley.
Filtrate collection and disposal system
Returns the filtrate back to plant headworks, generally by gravity.
Thickening and Dewatering Operations in a single unit
Two Distinct Sections :
Gravity Section: Acts as a thickening unit by gravity separation of solids & water and concentrates the sludge.
Pressure Section: Acts as a dewatering unit by sandwiching and squeezing the sludge between the two sets of belts and subjecting the sludge to increasing pressure as the belt moves to discharges point.
Belt Press is one of the most suitable option for continuous Operation Substantial energy saving vis-a-vis other dewatering technologies. Slow Speed machine, hence less wear & tear and low maintenance cost.