While doing some fact checking for a consulting job, I had cause to review Australian Standard AS 2671-2002; Hydraulic Fluid Power-General Requirements for Systems. This Australian Standard is basically the International Standard, ISO 4413 with some amendments based on the local advisory committee’s input.
One of these amendments has to do with pump suction strainers. Section 8.3.3 of ISO 4413:2010, states: Unless agreed between the purchaser and supplier, filtration on pump suction lines shall not be used. Inlet screens or suction strainers are acceptable.
HOWEVER, AS 2671 replaces the above text with: Unless agreed between the purchaser and supplier, filtration, inlet screens or strainers on pump suction lines shall not be used.
In other words, according to ISO 4413, a machine builder can install a suction strainer WITHOUT consultation with and agreement from the machine owner. But NOT in Australia. To comply with AS 2671, the machine builder must have agreement from the machine owner to install any kind of filtration on the pump intake line–including a suction strainer.
So what does the Australian advisory committee know that their ISO counterparts don’t? It’s this: if the hydraulic reservoir is properly designed and maintenance standards are decent, poor inlet conditions caused by a suction strainer is a bigger threat to pump life in the long run, than contaminants and debris that should not be in the reservoir in the first place.
Bottom line: the installation of a suction strainer on a hydraulic pump inlet can be a costly mistake. And to discover six other costly mistakes you want to be sure to avoid with your hydraulic equipment, get “Six Costly Mistakes Most Hydraulics Users Make… And How You Can Avoid Them!” available for FREE download here.