Pressure Filters

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Pressure Filters:

CESCO offers several different pressure filter designs (e.g. horizontal and vertical plate units), and they are often utilized as polishing filters on slow filtering and/or dilute streams to provide optical clarity.

Some designs can use precoat filter aid applied to the filter cloth (e.g. diatomaceous earth), which can be used to remove particulates down to about 0.4 micron in size In this case, the filter aid becomes the media that actually is performing the filtration and the filter cloth acts as a support and drainage layer. Other designs use just filter cloth or screens to perform the filtration, with some units having the ability to "backpulse" in order to continue the processing of fluids.

Self-Cleaning Designs

Automatic Pressure Nutsche Filter/Filter-Dryer: CESCO is proud to be an authorized representative of COMBER, and industry leader in pressure filration and vacuum drying technology:

http://www.comber.it/

CESCO offers pressure nutsches that can be used to automatically filter, wash, reslurry, dry, and discharge the cake from the single filter plate (with an option for full cake heal recovery).

These units consist of:

1. Vessel - A cylindrical, vertical pressure vessel with dished top head and welded or flanged flat base. If the base is flanged, the base is secured to the shell either with traditional clamps or with an automatic bayonet open/close mechanism. The base of the vessel has a single flat filter base with a filter cloth or screen.

2. Agitator - Typically with two or three S-shaped blades that can be moved up and down and rotated in either direction, to allow for reslurrying the solid-liquid contents, for cake smoothing (to eliminate cracks for efficient displacement washing), and for mixing up the cake and turning it over to allow for efficient drying via vacuum or warm gas introduction into the vessel.

3. Discharge Valve - Typically a plug-type valve on the side of the vessel wall at the filter plate level. For cases where the operations call for reslurry the cake and discharging as a slurry for downstream processing, a slurry discharge valve can be located either on the side wall at the filter plate level, or in the filter base.

4. Heated Jackets/Shaft - The filter/filter-dryer can be designed with heated side walls, filter bases, top heads, dust collector housings, and shafts and blades for extremely efficient drying duties. An optional microwave drying system may also be designed for use with this filter/dryer.

This unit is often used in cases where the cake collected is the valuable product, but may also be used to filter out (and optionally wash and dry) waste solids. This unit can be designed for processing cake heights up to 20" thick, and for most applications the cake height ranges from about 6-14". The unit is typically sized based on solids volume per batch.

Horizontal Pressure Leaf Filter:

CESCO offers a premium, self-cleaning leaf filter designed for efficient filtration in the most severe applications. Due to a superior, patented sluicing design, this unit maintains its fully rated capacity even when heavy, sticky or unusually tenacious cake is encountered. Its efficient sluicing system assures thorough cleaning of every square inch of filter surface area each cycle.

To summarize, this unit is a horizontal pressure leaf filter with vertical leaves on a center filtrate shaft. The shaft rotates during cleaning to more effectively clean the leaves using spray jets or stationary scraper blades in the dry cake discharge model. The unit offers higher flux rates, better cleaning and easier cleaning than conventional fixed leaf filters.

Materials of Construction: Carbon Steel, Coated Steel, Stainless Steel, Special Alloys

Maximum Flow: 3,000 GPM

Maximum Pressure: 500 PSI

Minimum Flow 50 GPM

Minimum Pressure: 50 PSI

Tubular Backpulse Filter:

CESCO offers a tubular backpulse filter designed to accomplish submicron filtration without the use of precoats or filter aids. This makes it possible for small amounts of product to be recovered from waste streams and returned to the process stream without contamination. This unit is less expensive and easier to operate than other designs.

Materials of Construction: Carbon Steel, Coated Steel, Stainless Steel, Titanium

Maximum Flow: 1,000 GPM

Maximum Pressure: 200 PSI

Minimum Flow 15 GPM

Minimum Pressure: 50 PSI

Standard Filter Sizes

Cutaway of Backpulse Filter Element

Tubular Filter:

CESCO offers a classical tubular filter. The filter consists of a vertical vessel with tubes suspended from a tube sheet. The filtration is from the outside of the tube to the inside. The filtered liquid then flows up the inside of the tube through the openings in tube sheets into the top head. The top head area serves as a reservoir to filtered liquid.

This filter has several design features which assure proper cleaning on every cycle. The advantages of the tube filter design are:

- Self-contained internal backwash liquid source. No external backwash pumps or tanks are required.
- Rapid cleaning cycles which result in minimum downtime. Many times this can eliminate the need for an additional filter.
- The entire tube bundle is removable as a unit for easy replacement and/or maintenance.
- A small footprint of the filter minimizes installation costs and facilitates installation in existing locations.
- Minimum auxiliary equipment requirements further reduce costs and ease installation. This filter has been used for many applications depending on the precoat material. Materials include diatomaceous earth, cellulose, powdered ion exchange resin and more.

Materials of Construction: Carbon Steal, Coated Steel, Stainless Steel

Maximum Flow: 1,000 GPM

Maximum Pressure: 200 PSI

Minimum Flow 15 GPM

Minimum Pressure: 50 PSI

Fixed Leaf High Volume Filter:

CESCO offers a versatile, pressure leaf filter for tough filtration jobs involving large volumes of liquid. It is especially useful where a dry cake discharge is desired. Designed for operating efficiency and easy maintenance, this filter is offered in two basic models: one with a retracting tank, and one with a retracting bundle design.

For the design with the retracting vessel, all connections, including the filtration outlet nozzle, are located in the stationary front section. Retraction of the shell exposes the entire leaf bundle for ease of inspection and maintenance of the filtration surfaces. It is available in cylindrical or conical tank configuration.

The more common retracting bundle design offers good flow distribution and pressure control. It provides excellent sluicing characteristics and features easily accessible filter leaves for quick cleaning and inspection. It is available in cylindrical, conical, double-conical, or trough tank configuration.

Vertical Pressure Leaf Filter:

CESCO offers a vertical plate/vertical tank filter that is specially designed for performance in areas with restricted floor space. It can be easily adapted to achieve a variety of results in a wide range of applications. The rigid filter plate design is economical and designed for minimal maintenance.

Vertical Pressure Leaf Filter with Bottom Scavenger Filter Plate Design
& Quick-Opening Bottom Cake Discharge

Internals of the vertical pressure
leaf filter showing the filter plates

The filter plates

may be cleaned without opening the filter vessel. This may be accomplished using a fixed overhead sluice to wash the cake off the plates (wet cake discharge), or via a vibrator connection which will shake the cake off of the plates (dry cake discharge).

CESCO offers a variety of options which can be added to the vertical filter. Hydraulically operated quick opening covers, and bottom drop out doors are available. Steam coils or jackets are easily adapted. All equipment and accessories can be furnished skid-mounted and ready for start-up complete with pump and motor, slurry feed equipment and tank.

Manual Cleaning Designs

Horizontal Plate Filters:

CESCO offers a Horizontal Plate Filter, which is designed for polishing and for security filtration of liquids with limited solid content. Design features include: maximum cake stability due to horizontal position of filter plates, ability for intermittent operation, complete recovery of product by the scavenger plate, no unfiltered hold-over, and perfect sealing of filter media by tie rod compression at center and periphery of all filter plates.

Horizontal Pressure Plate Filter

Filter Plate Stack

The standard Horizontal Plate Filter is compatible with any kind of filter media (fabric, metallic wire cloth, or filter paper) and all types of filter aids. Due to the position of the plates, only a very thin precoat of filter aid is necessary. The cake is evenly distributed, assuring economical operation and uniform clarity. All Horizontal Filter Plate Vessels can be supplied with a heating or cooling jacket.

Standard Filter Cartridge Sizes (Diameter) - 44", 33", 18", 14", 8"
Available Filter Plate Materials - carbon steel, most stainless steels, many exotic metals, polypropylene
Available Filter Housing Materials - carbon steel, most stainless steels, many exotic metals, a variety of linings
Filtration Area - up to 350 sq feet
Types of Filter Media Available - Since the media is clamped in position by means of positive bolted action, all types of filter paper, woven wire, membranes, and cloth on the market may be used.

Typical Horizontal Plate Filter Set-up with Precoat Tank and Body Feed Tank:

Cartridge Filters:

CESCO offers a variety of cartridge filter housing designs that can be used with filter cartridges that are supplied by all the major filter cartridge suppliers. Both industrial and sanitary designs are available. The housings can be designed for use with depth type cartridges (e.g. lenticular cellulosic), pleated style final polishing cartridges, etc. Units are available in most stainless steel and higher alloy materials, as well as coated housings.