Hydac BF Tank Breather Filter, up to 11,000 l/min

Clean air in and out of the oil tank

The Hydac BF is a tank breather filter. When oil level or temperature changes, a reservoir breathes, and every breath carries dust into the oil unless the air is filtered. The BF series puts a 3 µm absolute paper element in that air path and is available in ten sizes, from BF 4 to BF 9, for air flows up to 11,000 l/min.

Housings screw onto the tank or are bolted to a flange, depending on size. Sizes 5 and 52 include an oil mist trap as standard, and size 9 has an oil mist trap with a drain plug.

Technical specifications

Selecting the right size and code

Match the breather to the tank and pump flow. Small units such as BF 4, 10, 3 and 30 suit compact tanks; BF 7 and 72 and BF 5 and 52 have replaceable elements for larger reservoirs; BF 8 and 9 mount by flange. The code format is shown for each group, for example BF P 3 G 3 W 4 .X /-RV for BF 3, with the element material (P paper, BN Betamicron on sizes 5 and 52), the size, the connection (G thread to ISO 228, N NPT, U UNF or M metric) and the indicator type (W for none, K gauge or UBM vacuum gauge).

The check or bypass valve RV (not on BF 4) can be ordered with a stated pressure setting, for example 0.2 or 0.4 bar. It supports the suction behaviour of the pump but the datasheet warns that it is not 100 percent air-tight or leakage-free. Connection threads range from G1/4 on BF 4 up to G2 1/2 on BF 5 and 52.

Fluid compatibility and servicing

Standard models are suitable for mineral and lubrication oils. A table in the datasheet lists which sizes are suitable for HFA, HFC and HFD-R fluids, and for biodegradable HTG, HE, HPG, PAG and PRG types. Check that table against your fluid before ordering.

The paper element cannot be cleaned, so replace it at the same intervals as the fluid filters and at least every twelve months. Give us the tank connection thread, the pump flow and the fluid when you ask for a quotation.

Housing material and retention capacity by size, from the datasheet:

How the Hydac BF works

A hydraulic tank breathes when the oil level or temperature changes. The BF fits on the tank vent and cleans the air that moves in and out. Air passes through a paper element that holds back particles down to 3 micrometres. Dry, clean air enters the tank, and the oil stays free of dust. The element cannot be cleaned, so it is replaced when it is full. A clogging indicator shows when that is needed.

Where the Hydac BF is used

• Hydraulic power units
• Lubrication oil tanks
• Gearbox reservoirs
• Mobile machinery tanks
• Dusty plant environments

Selection checklist for the Hydac BF

• Air flow, up to 11,000 l/min
• Size from BF 4 to BF 9
• Connection thread: ISO 228, NPT, UNF or metric
• Thread or flange mounting
• Housing material
• Clogging indicator type
• Check or bypass valve RV
• Fluid type and oil mist trap

Installation, commissioning and maintenance notes for the Hydac BF

Screw the BF onto the tank connection, or bolt it to a flange for the larger sizes. Make sure the seal sits well. Size it for the full pump flow so the tank does not see a vacuum. Read the indicator on a routine. Change the element as often as the fluid filters, and at least every 12 months.

Requesting a quotation for the Hydac BF

Please send the tank volume, the pump flow, the fluid, the connection and the quantity. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.

Hydac BF housing materials

The BF 4 and 3 use plastic coated steel. The BF 5 and 52 use steel. The BF 8 uses galvanised steel. The BF 9 uses aluminium. The BF 10, 30, 7 and 72 use glass-fibre reinforced plastic.

Hydac BF dirt capacity

The BF 10 holds 2.9 g, the BF 3 and 30 hold 6.2 g, the BF 7 holds 26.1 g, the BF 72 holds 52.2 g, the BF 5 holds 85.1 g and the BF 52 holds 170.2 g.

Hydac BF indicators

The VMF pressure gauge switches at 0.6 bar. The UBM vacuum indicator switches at 0.035 bar.

Hydac BF seals and temperature

Seals are NBR on the filter and polyurethane on the element. The temperature range is minus 30 to plus 100 degrees C.

Breather records for the Hydac BF

Record the element change dates and the indicator readings.

Choosing the right Hydac BF size

Choose the size from the peak air flow of the tank, with the next size up if the oil is dusty.

Documents and quotation

The datasheet (EN 7.408.4/05.20) is attached. Related: filter housings and the Hydac RFM return line filter.