Technology news 11

Filtration+Separation May/June 2012

Donaldson has developed the new P-EGS stainless steel filter housings for steam filtration. According to the company, in combination with the filter elements of the (P) GSL N series significantly higher flow rates are achieved in the same space than is possible with conventional solutions. Plant engineers and OEMs can realise more compact designs, for example in sterilisation circuits for food and beverage production, with the new filters.

The new steam filter housings are manufactured of high quality stainless steel (316 L material). Although the filters are very compact, they can process up to 600 kg of steam per hour (at 1 bar g). The housing seals are designed for operating temperatures up to 200°C. The filter housings are approved for direct food contact and comply with FDA regulations (CFR Title 21).

Donaldson adds that the particular advantages of the new steam filter housings are most evident when they are equipped with the filter elements of series (P)-GSL N. These filters use a pleated stainless steel fibre web, which enables the retention of

contaminants down to a size of 0.01 μm (10 nm) at an efficiency of >99.996%. The filter medium offers a much larger filtration surface in comparison to conventional sintered steel filter elements, thereby creating the pre-conditions for a high dirt holding capacity while maintaining a low differential pressure.

In practice, this results in a significant reduction of the individual filter and within larger installations to a reduction of the required number of filters. A practical comparison (1 μm saturated steam, 1 bar g) between the up-to-now used P-EG filter housings with sintered steel filter element P-GS VE and the new P-EGS housings with (P)-GSL N filter element shows that eight 30 inch sintered steel elements can be replaced by a single 10 inch stainless steel fibre web element at a rate of 880 kg of steam per hour.

The steam velocity and initial pressure increase, but remain below the critical value of 40 m/s and 100 mbar. The housing volume is reduced by 95%, the costs of the filter by 80% and the investment costs due to the smaller pipe diameter by about

60% (DN200 to 3”). Also the savings due to the less frequent filter element change are not to be underestimated, especially since the new (P)-GSL N elements can be recycled up to 50 times in an ultrasonic bath or by back-flushing. With these features, the new steam filters create the

condition for more compact, cost-effective solutions in the steam technology. Typical applications are sterilisation cycles in dairies, breweries and in the food industry. The range also includes a special version for the preparation of pure oxygen.

www.donaldson.com

New steam filters reduce investment costs and increase efficiency

Table 1: Practical comparison of the filter housings.

P-EG 1536 P-EGS 0030

Number of elements 8 × 30/30 P-GS VE (1 Mic.)

1 × 10/50 (P)-GSL N (1 Mic.)

Initial delta p (bar) 0.062 0.099Pipe velocity (m/s) 6.43 39.8Weight (kg) 135 11Volume (l) 190 8.8Height (mm) 1600 508Condensate (kg/h) 42 3Connection DN200 G3“Costs housing (€) 13.375 2.785Costs elements (€) 8 × 900 1.174Total (€) 20.575 3.959Saving (€) 16.616

Figure 1: The housing volume of the

P-EGS housing in combination with the

(P)-GSL N filter elements is reduced by

up to 95 % in comparison to common

ranges.

Figure 2: The filter (P)-GSL N uses a

pleated filter medium made of stainless

steel fibre web and has a high dirt

retention capacity.