Outotec says its new Larox® PF-DS tower press filter combines two proven technologies in one unit to meet the challenging process requirements of the chemical process industry.

With filtration applications getting more demanding due to challenging materials, increased cake washing needs, strong acid processes, and fine grinding, there is an increasing need for technologies that can handle these challenges in a reliable and more automated manner, Outotec says.

The new Larox PF-DS is a tower press filter where the plate pack is composed of polypropylene membrane filter plates stacked on top of each other. The cake forms between the closed filter plates on the top and bottom side of the filtration chamber, hence it being called a double-side filter.

The mechanical operation and frame of the Larox PF-DS are shared with the Outotec Larox PF pressure filter while the unique filtration process is powered by the double-side plate pack from the Outotec Larox DS filter (earlier known as Hoesch® DS).

The individual filter chamber has a double-side filtration area of 4.7 m2 and an operating pressure of up to 16 bar. The plates are stacked vertically to give a total filtration area of 38–94 m2 depending on the unit size, according to Outotec.

One endless filter cloth runs through the whole filter and one side of the filter cloth is used for filtration. A wide range of different cloth types is available to meet the application needs, the company said. This filter cloth ensures efficient discharge of all cake from each individual chamber at every cycle, eliminating the need for manual intervention.

With the PF-DS now sharing the mechanical design with the PF family, local Outotec service teams are available for technical support and maintenance needs. Likewise, the availability and compatibility of the spare parts is significantly improved compared with earlier technology.

Outotec said: “PF-DS Filters are fully automatic, operating either with a standalone panel or through a distributed control system. Automation extends beyond basic filter sequencing to full process control, ensuring consistent results under varying process conditions.”

The filtration process is a batch operation which includes filtration, membrane pressing and air drying stages, with several options for cake washing added to the process depending on customer needs.

When the process cycle is ended, filter cakes will be discharged from the one side of the filter. Due to the cloth being on both sides of the chamber together with the cloth scrapers, cake discharge is fully automatic without an operator present.

After each cycle, the moving filter cloth passes through water sprays to remove any embedded solids. This maintains cloth permeability, consistent filter performance and extends cloth life, according to Outotec.

The single cloth system makes cloth change simple and quick, typically taking as little as 30 minutes. Furthermore, cloth inspection can be carried out without the need for equipment shutdown.