Hydac LF and LFF Low-Pressure Inline Filter, up to 100 bar

Lightweight inline filters for pressure lines up to 100 bar

The Hydac LF is an aluminium inline filter with a screw-in aluminium bowl, used on pump outlets, lube lines and charge circuits up to 100 bar. The LFF version is suitable for oil flow in both directions. The same sheet covers sizes from the small LF 30 up to LF 660.

Maximum flow for the series is 500 l/min. Standard equipment includes a clogging indicator connection, mounting holes in the head and, from LF 330, a drain screw with pressure relief.

Technical specifications

Choosing a size and decoding the order

The code example is LF ON 60 I C 10 D 1 .X /-L24. After the type and element material come the size, the pressure letter I (100 bar), the connection letter (B, C, E or F), the micron rating, the indicator type and the type code. Supplementary details include a bypass cracking pressure (B6 for 6 bar; with no figure the filter has no bypass), pressure release or oil drain screw SO184, FPM seals, indicator lamps and W for HFA and HFC emulsions when a clogging indicator or V or W elements are used.

Port sizes pair with body size as follows in the dimension table: LF 30 has G1/2; LF 60 and 110 have G3/4; LF 160 and 240 have G1 1/4; LF 330 and 660 have G1 1/2. Element and indicator codes follow, for example 0060 D 010 ON and VM 5 D .X.

Notes for installation

An oil drain screw is available up to LF/LFF 240 and standard from size 330. A bypass valve integrated in the head and separate from the main flow can be specified. Earth the housing and cut the power before removing an electrical indicator connector.

Compatible fluids are hydraulic oils H to HLPD, lubrication oils, compressor oils, biodegradable HETG, HEES and HEPG, and fire-resistant HFA to HFD; high-water-content fluids on request. Test and approval certificates are available on request. For pressures above 100 bar, look at the DF or MDF series instead.

Gradient coefficients for Optimicron (ON) elements, in mbar per l/min at 30 mm2/s:

How the Hydac LF inline filter works

An inline filter removes solid particles from the oil that passes through it, so valves, pumps and bearings downstream stay clean. In the Hydac LF, the oil enters the head, flows through a filter element in the bowl and leaves clean. The element traps the particles in its media. As the element loads with dirt, the pressure drop across it rises, and the clogging indicator shows when the element must be replaced. The LFF version works with oil flow in both directions.

Where the Hydac LF is used

• Pump outlets in hydraulic systems.
• Lube oil lines.
• Charge circuits.
• Mobile and industrial hydraulics up to 100 bar.
• Circuits where oil flows in both directions, using the LFF.

Selection checklist for the Hydac LF

• Series LF for one flow direction, or LFF for both.
• Size LF 30, 60, 110, 160, 240, 330 or 660.
• Maximum flow of up to 500 l/min.
• Nominal pressure of 100 bar.
• Temperature range of -30 to +100 degrees C.
• Aluminium head and bowl.
• Element material: Optimicron, Betamicron, wire mesh or stainless steel fibre.
• Filtration rating from 1 to 20 micron, or 25 to 200 micron for wire mesh.
• Connection of G1/2, G3/4, G1 1/4 or G1 1/2.
• Seals in NBR, with FPM or EPDM as options.

Installation, commissioning and maintenance notes

Fit the filter in the line with the flow arrow in the right direction, and leave room under the bowl to remove it. Use the mounting holes in the head to fix the filter firmly. Connect the clogging indicator to give a warning, and replace the element when it shows. The optional bypass valve opens at 6 bar if the element blocks, but a bypass lets dirty oil pass, so replace a blocked element promptly. From size LF 330, a drain screw with pressure relief makes service easier.

Requesting a quotation for the Hydac LF

Send the flow, the pressure, the fluid and the filtration rating. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.

Reading the order code

The example code LF ON 60 I C 10 D 1 gives the type, the element material, the size, the pressure letter I for 100 bar, the connection, the micron rating and the indicator type.

Clogging indicator

The VM differential pressure indicator is set at 5 bar, and at 8 bar on the LFF.

Element collapse pressure

The collapse pressure is 20 bar for the ON and wire mesh elements and 210 bar for the BH4HC and V elements.

Filter records

Record the full code, the element change dates and the indicator status of each filter.

Choosing the right size of Hydac LF

Start from the maximum flow of the pump and choose a size whose rated flow covers it at the viscosity of the oil in use. A cold start gives a high viscosity and a higher pressure drop, so allow a margin. Select the micron rating for the cleanliness the components need, and a finer element for servo valves than for simple cylinders.

Weights

The weight with the element runs from 0.8 kg for the LF 30 to 11 kg for the LF 660.

Documents and quotation

The datasheet (EN 7.563.7/07.22) is attached. Send the code, the micron rating and whether you need a bypass. Related: filter housings and the Hydac RFM return line filter.