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Brand: Hydac
Hydac DFDK Change-Over Pressure Filter, up to 315 bar
Description
A duplex filter you can service without stopping the plant
The Hydac DFDK puts two filter bowls on one ductile iron head with a ball change-over valve between them. One side filters while the other is isolated, so an element can be changed with the system running. That is the reason these units show up on turbine lube oil skids, press hydraulics and other lines where a shutdown costs more than the filter.
The series covers flows up to 1800 l/min. DFDK 30 to 660 (type codes 1.X and 2.X) is rated at 315 bar nominal; the top-removable DFDK 1320, 2640 and 3960 (type code 3.X) is rated at 160 bar.
Technical specifications
| Parameter | Specification |
|---|---|
| Series | DFDK, sizes 30, 60, 110, 140, 160, 240, 280, 330, 500, 660, 990, 1320, 2640, 3960 |
| Type | Change-over pressure filter with ball change-over valve |
| Maximum flow rate | Up to 1800 l/min (series) |
| Nominal pressure | 315 bar (type codes 1.X and 2.X); 160 bar (type code 3.X) |
| Fatigue strength | 1,000,000 cycles at nominal pressure, 0 to nominal pressure |
| Temperature range | -10 °C to +100 °C; -30 °C to -10 °C limited to 157.5 bar |
| Filter head material | EN-GJS-400-15 |
| Filter bowl material | Steel; two-piece bowl on DFDK 990, 1320, 2640 and 3960 (optional on 660) |
| Clogging indicator | VD, differential pressure up to 420 bar; setting 8 bar |
| Elements per side | One for sizes 30 to 1320; two for 2640; three for 3960 (type 3.X) |
| Element materials | Optimicron (ON), Betamicron (BH/HC), stainless steel fibre (V), wire mesh (W/HC, W) |
| Filtration ratings | ON: 1 to 20 µm; BH/HC and V: 3 to 20 µm; wire mesh: 25 to 200 µm |
| Collapse pressure | ON 20 bar; BH4HC 210 bar; V 210 bar; wire mesh 20 bar |
| Connections | G1/2, G3/4, G1 1/2, SAE DN 50 (6000 psi), SAE DN 65 (3000 psi) |
| Seals | NBR (FPM optional) |
Change-over layout and order code
Standard equipment includes the ball change-over valve, a connection for a clogging indicator, a drain screw with pressure relief and, from size 330, a pressure equalisation line. The change-over can be an L configuration (standard) or a T configuration, where flow passes through both sides at once; T is possible only with BH/HC and V elements. A detent pin to lock the lever is available for DFDK 160 to 280 and, as SO668, for 330 to 1320.
The code in the datasheet reads DFDK ON 160 Q L F 10 D 1 .X /-L24: series, element material, size, pressure letter (Q = 315 bar, K = 160 bar), change-over layout, connection letter, micron rating, clogging indicator letter and type code. Type code 1 is a one-piece bowl, 2 a two-piece bowl (660 to 1320) and 3 the top-removable design for 1320 to 3960. Optional extras are FPM seals (V), HFA and HFC suitability (W) and indicator lamps (L24 to L220, or LED).
Selecting and confirming
Size the filter on flow and element differential pressure rather than on line size alone, because a duplex body has to carry the full flow on one side.
Compatible fluids include hydraulic oils H to HLPD, lubrication oils, compressor oils, biodegradable HETG, HEES and HEPG, and fire-resistant HFA, HFB, HFC and HFD. Earth the housing and de-energise the system before removing an electrical indicator connector. Please confirm pressure class, element material and connection type with the nameplate of the unit you are replacing.
Elements per side, by size, as listed in the datasheet:
| DFDK size | Element per side |
|---|---|
| 30 | 1 x 0030 D |
| 60 | 1 x 0060 D |
| 110 | 1 x 0110 D |
| 140 | 1 x 0140 D |
| 160 | 1 x 0160 D |
| 240 | 1 x 0240 D |
| 280 | 1 x 0280 D |
| 500 | 1 x 0500 D |
| 660 | 1 x 0660 D |
| 990 | 1 x 0990 D |
| 1320 | 1 x 1320 D |
| 1320, 2640, 3960 (3.X) | 1, 2 and 3 x 1320 D |
Documents and quotation
The datasheet (E 7.553.15/11.16) is attached. Send the complete DFDK code and the fluid. Related: filter housings and the Hydac SB330 bladder accumulator.
Datasheets & Documents
- Datasheet Hydac DFDK change-over pressure filter datasheet (E 7.553.15/11.16) Download
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About brand
Hydraulic power units around the world carry Hydac parts: accumulators, filters, coolers, valves and the sensors that watch pressure and temperature. The company was founded in 1963 in Sulzbach/Saar, Germany. Seven Star LLC lists Hydac SB330 bladder accumulators, RFM return line filters and the EDS 3400 and ETS 1700 electronic switches, and sources Hydac spare parts for plants in Oman and the GCC.
Hydac product families
Hydac groups its program into hydraulics and filtration (filters, accumulators, sensors and measurement), control technology (valves, control blocks, ball valves), thermal management (air and fluid coolers) and drive technology (pumps, motors, cylinders). The four listed products come from the first group and are common on lube oil skids, presses, turbine control units and mobile machines.
Ordering Hydac parts: what we need
- Accumulators: full model code, volume, pressure rating, bladder material and the approval required
- Filters and elements: housing code, element code, micron rating and clogging indicator type
- EDS and ETS switches: full code with range, output version and connector
A nameplate photo covers most of this.
Browse Hydac products by category: Filtration Systems, Pressure Instrumentation.
Related products
Frequently Asked Questions
Can the elements be changed during operation?
Yes. The ball change-over valve switches the flow to the second filter side so the first can be serviced.
What is the pressure rating?
315 bar for type codes 1.X and 2.X, and 160 bar for the top-removable type 3.X.
What does the T configuration do?
It allows flow through both sides at once and is possible only with BH/HC and stainless steel fibre elements.
Which clogging indicator is used?
The VD differential pressure indicator, set to 8 bar as standard.
How many elements does each side take?
One element per side from size 30 to 1320; two on the 2640 and three on the 3960 per side.
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