IWE’s range of small filter presses has plate pack sizes 250, 470 and 630mm square. The plate suspension system is the sidebar version and the circular sidebars have stainless steel sleeves.
The hydraulic closing device is actuated either by a hand pump or an electronically driven pump. The 250mm square filter press is particularly suited to manufactures, research workers and universities who often require filter presses on relatively small capacity which are equal in performance to large commercial installations.
Whilst the 470 and 630mm square filter presses have earned the confidence of manufactures and processors over the entire spectrum of industry. The filter press sizes can be supplied with plate/frame, recessed plate packs of membrane plates.
IWE’s range of large filter presses have plate pack sizes 800, 915, 1000, 1200, 1300, 1500/2000 and 2000mm square. All plate sizes are available for use in sidebar or overhead slung plate suspension designs with the exception of 800mm square plate size which is only available in a sidebar framework and the 915mm square plate size which is only available in a overhead slung framework.
The need to reduce man power on process plants and to ease the nature of the work involved, has caused for mechanisation to automate the operational sequence of filter presses fitted with these larger plate sizes. Both overhead slung and sidebar filter presses can be fully mechanised which provides automatic means of closing the plates together, sealing the filter press at a pre-determined pressure moving each plate individually to afford cake discharge, controlling the movement to minimise filter cloth wear due to impact and providing a safety system whereby electric power is cut off if the operator approaches the filter press while the plate transfer mechanisation is in operation.
The development of mechanisation makes one man filter press operation possible whilst maintaining good operational efficiency.
Mechanised Presses can be supplied in both sidebar and overhead form and incorporate features such as:
- Double acting hydraulic opening and closing
- Hydraulically operated hinged drainage trays
- Plate movement system
- Photo electric light guards
- Cloth washing
Mechanical Plate Movement
Mechanisation of the filter press invariably includes our plate movement system which is infinitely variable for use on our sidebar or overhead design and also fully adjustable to accommodate polypropylene or cast iron plates. A unique feature of our system is the hold back facility so that only one plate at a time is transferred with a positive stacking when deposited.Mechanised sidebar press featuring plate movement system, double acting electro hydraulic opening/closing, hydraulically operated hinged drainage trays and photo electric light guards.
Our range of membrane filter presses covers every size requirement. The membrane plate is a significant technological development of the standard recessed plate or every other plate has a flexible face which covers both sides of the plate.
The fundamental principle of membrane operation realises that approximately 75 to 80 per cent of the product to be filtered passes through the filter in the first third of the cycle time. At this point, in each chamber two ‘half’ cakes have been built up. Press feeding is stopped and the flexible membrane outer surfaces are inflated by applying compressed air pressure (or water) behind the membrane surfaces. The two halves of cake in each chamber are then squeezed together, under pressure, forming a single cake of a very homogenous consistency.
Clearly, utilisation of the membrane filter press offers in many applications the following advantages over plate and frame and recessed plate filter presses:
- Increased product throughput
- Reduction of residual moisture of the filter cake
- Filtration, wash and cake cycles shorter
- Cake air blasting can be omitted.
Drier cakes means energy saving on cake drying and transportation The optimised cake structure facilitates quicker and better washing results Varying product quantities and compositions present no problems to the membrane filter press, irrespective of chamber depth, a cake will always be formed.
We offer a service to all customers currently using filter presses (regardless of origin of press) the scope of which covers; the supply of spare of replacement parts, and modification, refurbishing or automation of presses and associated plant to give improvement in performance, or reduced maintenance.
A sample of the options we can offer to give improved plant performance are as follows.
Automatic hydraulic filter press closing system
Hydraulic systems comprising power packs and hydraulic rams can be provided, specially designed to suit individual requirements. Designs are available to permit conversion of manually closed presses to hydraulically closed, both hand operated and motorised, and also to convert manually locked hydraulically closed presses to automatic pressure sustained systems.
Press Feed and cake disposal systems.
All plant systems can be engineered to fully integrate the control of filter presses, feed pump and cake disposal systems using microprocessor equipment of any manufacturer.
The choice of a recessed filter press, plate and frame filter or membrane plate filter press is determined by the application which normally falls into one of three categories :
1. The separation of solids and liquids under conditions where there is sufficient solid material in the feed slurry to form a filter cake.
2. The separation of solids and liquids where there is sufficient solids to form only a thin layer on the filtering media.
3. The removal from a liquid of small quantities of finely divided solids, sometimes with the assistance of filter aids, this operation is normally described as clarification or polishing.
In the first category the filter press criteria is to provide filtration area and volume for cake filtration, in the second and third categories the filter press essentially provides filtration area and the capacity for cake filtration is unimportant. For the first application a recessed plate filter press is usually recommended with the plate and frame design normally recommended for second and third category applications.
Recessed Plate Filter Press
In the recessed type of press the recess is formed by a raised rim which stands above the drainage surface and the thickness of cake formed therefore twice the depth of the recess on individual plates. The slurry to be filtered is normally fed into the filter press through a central hole that feeds each chamber at the same time. The solids are retained within the recessed hollow chamber and the filtrate passes through the media into an internal manifold or away through drain cocks or directional bibs.
Plate and Frame Filter Press
In the plate and frame type of press the chambers are formed by the use of a hollow frame which is placed between two plates whose rim or joint surfaces are nearly flush with their drainage surfaces. The slurry to be filtered is fed into the press through a manifold formed by ports in each plate and frame and delivered into each frame by suitable connecting ports. The solids are retained within the hollow frame whilst filtrate delivers through the media into a collection manifold by way of additional ports in the plates or through drain cocks or directional bibs.
Membrane Plate Filter Press
The membrane system has proved to be useful in certain applications, typical of which are the filtration of dyes, pigments and yeast slurries.
1. 630 x 630mm square, recessed plate filter press used for dewatering metal hydroxide sludges from a plating shop effluent treatment plant
2. 800 x 800mm square, recessed membrane plate filter press used in filtration of fermenting vessel bottoms on a brewery installation.
3. 1500 x 1500mm square, recessed plate filter presses used for treatment of drinking water in a large Scottish town.