Hydac LPF Low-Pressure Inline Filter, up to 50 bar and 280 l/min

Aluminium inline filter for pilot, charge and lube lines

The Hydac LPF is an aluminium inline filter for low-pressure lines such as pilot supplies, charge circuits and lube lines. It has an aluminium head and a screw-in aluminium bowl and covers flows up to 280 l/min. LPF 35 and 55 are rated at 40 bar, and LPF 160, 240, 260 and 280 at 50 bar.

The standard model has no bypass valve, which suits circuits that must never pass unfiltered oil, and a bypass of 1, 3, 6 or 7 bar can be specified when the circuit needs one. A port for a clogging indicator is standard.

Technical specifications

Order code and element restriction

The datasheet example is LPF ON 160 G E 10 D 1 .X /-L24. After the type and element material come the size, the pressure letter (E = 40 bar for 35 and 55; G = 50 bar for 160 to 280), the connection letter, the micron rating, the indicator letter and the type code. Indicator choices are W (no port), Y and A (plugs), B (visual), C (electrical), D (visual and electrical) and BF, a visual mobile indicator for LPF 160 to 280 only. A return line indicator is possible on request.

The datasheet carries an explicit notice: only elements in Optimicron and in the …/HC materials can be used in LPF filters. Supplementary details include a bypass cracking pressure (B6), BF indicator on the left or right (BFL, BFR), a pressure-relief and oil drain screw (SO184), FPM seals, lamp voltage and HFA or HFC suitability (W).

Selection notes

The replacement element is coded like 0160 D 010 ON. Compatible fluids are hydraulic oils H to HLPD, lubrication oils, compressor oils, biodegradable HETG, HEES and HEPG, and fire-resistant HFC and HFD fluids; fluids with a water content above 50 percent are available on request. For higher pressures see the LF, MFM or DF series.

Earth the housing, and keep power to an electrical indicator off while its connector is removed. Send the nameplate code or the pressure, flow, port thread and micron rating so the right size and connection can be confirmed.

Key features of the LPF series

• Aluminium head and screw-in aluminium bowl keep the housing light for low-pressure circuits where a steel pressure filter would be oversized.
• Six sizes (35, 55, 160, 240, 260, 280) cover flows up to 280 l/min in one family, so a plant can standardise on one housing style.
• No bypass as standard, which guarantees that every drop of oil passing the filter has been filtered.
• Optional bypass settings of 1, 3, 6 or 7 bar for circuits where flow must never be blocked, such as lube supplies.
• Clogging-indicator port fitted as standard, with visual and electrical indicator options.
• Three element families: Optimicron for fine filtration at low differential pressure, Betamicron for high collapse strength, and wire mesh for coarse protection.

Choosing size, element and bypass

Size

Start from the maximum flow in the line, including flow peaks from accumulators or cylinder return, and select a size that keeps the clean-element pressure drop low at the operating viscosity. Cold-start viscosity matters: oil that is thick at start-up raises the differential pressure sharply, so the size check should be done at the lowest expected oil temperature as well as at normal running temperature.

Element

The micron rating follows the cleanliness the most sensitive component needs. Servo and proportional valves usually call for the fine end of the range, while gear pumps and lube circuits tolerate coarser grades. Where the filter has no bypass, the element collapse rating must be high enough for the worst pressure the line can see; Betamicron BH4HC, with a 210 bar collapse rating, gives the largest margin, while Optimicron is rated at 20 bar and wire mesh at 30 bar.

Bypass or no bypass

A filter without bypass protects downstream components absolutely but will stop flow if the element is left to block. That is why an electrical clogging indicator wired to the control system is strongly recommended on no-bypass filters. With a bypass, the system keeps running on a blocked element but passes unfiltered oil, so the indicator is equally important.

Installation and service

• Install in the flow direction marked on the head and leave clearance below the bowl to unscrew it and withdraw the element.
• Fill new filters with clean oil where possible to reduce air in the circuit at start-up.
• Change the element when the indicator signals, not only on a calendar basis; and after flushing a new system, expect the first element to load quickly.
• Check the bowl seal during each element change and replace it with the correct material (NBR as standard, FPM or EPDM for special fluids).

Operating in Gulf conditions

Mobile and stationary hydraulics in Oman face fine sand, dust ingress through breathers and high oil temperatures. The -30 to +100 °C range of the LPF covers typical oil temperatures, but high ambient heat makes oil thinner and dust loading makes elements fill faster. Fitting good breathers on the tank and monitoring the indicator help get full life from the element and protect pumps and valves.

Information for your RFQ

• Full order code if known, for example in the format LPF ON 160 G E 10 D 1 .X /-L24, or the existing filter nameplate.
• Flow, maximum pressure, fluid type and operating temperature.
• Required micron rating and element material, and whether a bypass is needed.
• Connection type and indicator type (visual or electrical, with voltage).
• Quantity of spare elements required.

Documents and quotation

The datasheet (E 7.114.7/11.16) is attached. Related: filter housings and the Hydac RFM return line filter.