BS ISO 3968:2017 specifies a procedure for evaluating differential pressure versus flow characteristics of hydraulic filters and constitutes a basis for agreement between the filter manufacturer and user.

It also specifies a method for measurement of the differential pressure generated at different flow rates and viscosities by the relevant parts of a filter assembly, spin-on and any valves contained within the filter which are in the flow stream. The typical types of filter to be tested are as follows:

Type 1: which are spin-on filters in which the replaceable unit does not include a filter head (it might or might not include the element by-pass valve);

Type 2: which are spin-on filters in which the replaceable element is tested together with a filter head (it might or might not include the element by-pass valve);

Type 3: which are filter assembly, usually of the replacement element type, that is the housing (head and bowl) and element.


Cross References:
ISO 6415:2005 Ed 3 (R08)
ISO 4406:2017
ISO 2909:2002 Ed 3
ISO 4021:1992 (R08)
ISO 3675:1998
ISO 5598:2008 Ed 2
ISO 3448:1992
ASTM D4308-95
ISO 2944:2000
ISO 1219-1:2006
ISO 9110-2:1990 (R05)
ISO 9110-1:1990 (R05)
ISO 16889:2008 Ed 2


All current amendments available at time of purchase are included with the purchase of this document.