Hydac ELF Tank Breather Filter with Filler Strainer

One part for tank breathing and for filling the tank through a strainer

The Hydac ELF combines two jobs on the filler neck of a tank. The air filter top cleans the air that the tank breathes, and a filler strainer below it catches coarse particles when oil is poured in. That keeps new oil from carrying dirt into the reservoir during top-ups.

Sizes ELF 4, 10, 3, 30, 7, 72, 5 and 52 are listed, with a lockable ELFL 3, for air flows up to 5500 l/min. The air element is a 3 µm absolute paper element.

Technical specifications

Models, options and ordering

Sizes 4, 10, 3 and 30 are a three-part design: an air filter top joined to a mounting flange by a bayonet plate or a threaded boss, with the filler strainer below. Sizes 5 and 52 have a two-part threaded top with an oil mist trap and one or two exchangeable elements. Sizes 7 and 72 have a two-part flanged top with an exchangeable element and a connection for a clogging indicator.

Code examples are ELF P 30 F 3 W 1 .X /-RV0.4 (flange connection, no indicator, check valve set to 0.4 bar) and ELF P 52 G 3 W 2 .X /-RV0.4 (G thread). The check or bypass valve is listed for ELF 10, 3, 30, 5 and 52 and is not 100 percent air-tight, so it is not suitable for tanks that must be fully sealed. An anti-splash device is available for ELF 10, 3, 30, 7 and 72.

Fluids and handling

Standard models suit mineral and lubrication oils. The datasheet table shows which sizes can be used with HFA, HFC and HFD-R fire-resistant fluids and with biodegradable HTG, HE, HPG, PAG and PRG fluids; confirm your fluid against it. The element cannot be cleaned.

Change the element at least once a year or with each fluid filter change. Send the tank connection, the flow and any special option such as the lockable top when you ask for a quotation.

Housing material and retention capacity by size:

How the Hydac ELF breather filter works

A hydraulic tank breathes. When the oil level falls, air flows in, and when the level rises or the oil heats up, air flows out. Without a filter, this air carries dust into the oil. The ELF puts a 3 micrometre absolute paper element on the filler neck, so the incoming air is cleaned. Below the element, a strainer takes out coarse particles when oil is poured through the neck, which keeps the new oil clean. One part does both jobs and takes the place of a plain cap.

Where the ELF is used

• Hydraulic power units and machine tools.
• Mobile and construction machines.
• Gear units and lubrication tanks.
• Any reservoir that needs clean air and clean refilling.
• Systems with air flows up to 5500 l/min.

Selection checklist for the ELF

• Size: ELF 4, 10, 3, 30, 7, 72, 5 or 52, from the air flow of the tank.
• Lockable version ELFL 3, where tampering must be avoided.
• Housing material: steel, or glass-fibre reinforced plastic for some sizes.
• Filler strainer: synthetic or metal, by size.
• Connection: flange, or G thread on the larger sizes.
• Clogging indicator: VMF with a pressure gauge or the UBM vacuum indicator.
• Check or bypass valve, if the tank is to be kept slightly pressurised.
• Anti-splash device or filler adapter, where needed.
• Temperature range of -30 to +100 degrees C.

Installation, commissioning and maintenance notes

Mount the filter on the tank flange or thread, and make sure the opening is clear and the seal sits flat. Do not use the filler strainer as a way to push oil in fast, since it is meant for normal pouring. Replace the element as often as the fluid filters, and at least every 12 months. The check valve is not completely air-tight, so it is not suitable for tanks that must be fully sealed.

Requesting a quotation for the Hydac ELF

Send the tank air flow, the connection type and the options you need. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.

Why clean air matters

Fine dust drawn in with the tank air ends up in the oil and wears pumps and valves, so a good breather filter is one of the cheapest ways to protect a system.

Contamination retention

The data sheet lists the retention capacity for each size, from 2.9 g to 170.2 g, which helps plan the element change interval.

Records of element changes

Write the date and the element code on the tank or the service sheet.

Choosing between filler strainer types

Synthetic strainers are fitted to the smaller sizes, while the largest ELF 5 and 52 use a metal strainer. Check that the strainer mesh suits the oil you pour and that it can be removed for cleaning.

Housing materials

Steel, plastic-coated steel and glass-fibre reinforced plastic housings are offered, so choose the one that suits the site and the vibration level of the machine.

Documents and quotation

The datasheet (E 7.404.3/11.16) is attached. Related: filter housings and the Hydac RFM return line filter.