https://www.machinerylubrication.com/Read/611/suction-line-filtration http://www.insanehydraulics.com/letstalk/suction.html
I disagree with most of that. I've got hydraulic systems, with suction strainers that have cleared the 20k hour mark, and, I've never had a strainer cause a pump failure. I cannot control what the minions drop into the hydraulic tanks in the field here, and, several times, the strainer has prevented debris ingestion. To each their own, I suppose.
The topic of suction strainers has come up before and the general consensus was the people designing the hyd. system know what they're doing. They wouldn't put a suction suction in just to add cost to a machine.
Based on totally false premises - utter bollocks...
Well said Nige
Yeah, I cant buy what OP is selling.
heymccall That makes sense. No one will be touching my machine other than me though. If a pump over time fails, how would you know what the cause was? Seals breaking down/ one too many times the fluid became overheated? The possibilities are endless. Clearly you guys know infinitely more than I do about these machines. The analogy that comes to mind for me is you own a well maintained active fleet and I just bought my first sports car. There is wisdom that can only come through time. I am not trying to **** anyone off or take anyone's knowledge for granted. It is the opposite. I am trying to learn. For whatever reason these articles came up. I searched this site and found nothing about the topic. It is likely I don't understand the search feature on this site well enough yet. If this topic has already been beaten to death I apologies. Please post the link. The "it has always been done this way argument?" That was in the article if you haven't read it. They used to put lead in gasoline, it is a great lubricant. Asbestos is an incredible insulator. The O rings in the space shuttle, they always did it that way too. Nige, your response was basically "sit down and shut up kid!" With all due respect, why? I have been here long enough to know who captain kangaroo is. I am honored that you responded. What is the false premise? My mind always goes to this, how do the authors benefit by propagating easily disputable information? They aren't selling anything. It would be different if they were selling a useless device or if they were running for office and had a pump rebuilding company financing the campaign. My question is this, is the added stress of the strainer as significant as they state? Mine will absolutely never clog. That argument is out the window. But they are specifically talking about the location and the stress it puts on the pump. If someone like me was willing to take the risk of removing the last line of defense fail safe to get more power and longevity out of an old pump, why wouldn't I? Or is it bullocks? Will my pump die of old age regardless... Is it like removing a kidney so my heart will last longer while I am dying of dementia anyway? If this topic hasn't been beaten to death let the beating begin because if it isn't old news, it is coming anyway.
I would leave it in place, the only pumps I have seen fail on machines were from running them out of oil or contaminated oil not cavitation. I do check the strainers when changing hydraulic filters and even though nothing should be in them it can be suprising what there is that would wreck a pump. I think they save more pumps then they wreck.
Here's my take on it. Although one of the links is titled "Machinery Hydraulics" and the other if you read the article is also talking about machinery. But what is "machinery".? Certainly you would think that Big Yellow Iron hydraulic systems could be classed as "machinery", and to a certain point they are. However IMHO what our esteemed friends the hydraulic "experts" are talking about in those two articles is Industrial Machinery, at least that is my impression on reading them - and not for the 1st time I hasten to add. If you read each of them again with that in mind you can see it in your mind's eye. Fixed hydraulic installations in something like a factory, generally a much more clean & ordered world to the one we work in. OK, so what's the difference between BYI and an industrial installation.? Put quite simply - working conditions and people. Working conditions inasmuch as the equipment is often out there buried up to the bollocks in mud, and people inasmuch as any man and his dog will (in general terms) tip whatever oil they can lay their hands on into a machine hydraulic tank from whatever container (clean - what's that?) that happens to be within easy reach. That's where suctions screens come in on BYi. It's to stop the rags, hand wipes, tools, tree branches, dogs, & small children getting from the tank into to the pump suction............ You only have to look at some of the photos posted on HEF threads of what people find in implement hydraulic tanks to disabuse you of any thoughts whatsoever of removing any suction screen on a piece of BYI. As Mike L rightly pointed out above - suction strainers need to be serviced regularly and not forgotten. This is especially true on BYI.
case in point- i've never taken an automotive or diesel engine apart that did not have a screen on the oil pump inlet
there is a lot of stuff thats fine in theory, but in the real world---------
Yep, I've pulled many a paper towel and worse out of a hydraulic tank. If you think this discussion is contentious, look for one of the ones on here about whether an uncovered exhaust pipe going down the road destroys turbos by blowing air into them backwards and making them spin. Guys, please don't ban me for bringing that up!
Not going to hijack this thread and take it to turbos and exhaust stacks...but which ever camp you land in.... duct tape is cheap. I like the hydraulic discussion as I have yet to find the suction screen on the 580M!
Maybe nothing beyond the tank suction port worth protecting..?
Lets not even go to where people install a return filter where a suction filter is called for. Just because it fits don't mean it will work.
The issue with suction strainers has to do with putting a suction or negative pressure on the inlet side of a rotary piston pump. The pistons in piston pumps sit freely in the bores of the cylinder blocks and there is a plate between the cylinder block and the piston feet that sort of hold the feet against the swash plate. In normal operation there should be a little pressure against the top of the pistons all the time forcing them down against the swash plate making sure the piston feet are always touching. When you get a vacuum, the piston feet are pulled away from the swash plate until barrel rotates them to the outlet where there is great pressure. What happens in the feet get slammed into the plate and eventually destroyed. Mobile equipment is designed in a way that oil is pressurized slightly on the suction side of the tank. The usual method is to introduce air pressure into the hydraulic reservoir, but I know of some systems that actually put a centrifugal pump in the suction piping. The suction piping is also a large diameter and the hydraulic tank is located as close to the pumps as possible to reduce the possibility of creating a suction. Strainers are normally part of the design of the hydraulic system in heavy equipment for all the reasons mentioned above. Their physical size and type of mesh are carefully calculated to reduce the risk of creating a vacuum in the suction side of the pump. So summarize then, if the manufacturer designed the system with a strainer, it's supposed to be there. The other observation I can make is that what you get on the internet concerns the author's and producer's of information particular views on their subjects. Just because they produce a video or write and article doesn't mean they are an expert on any particular subject. They are presenting information based on their particular view of that subject. The internet has no censors, few fact checkers and even fewer real experts such as engineers and teaching professionals that have someone vet the information they are presenting. Looking around to confirm the veracity of the information presented was the right and proper thing to do, especially in this case. Thanks for the post.
Thank you Nige and everyone else who responded, It makes a lot more sense to me now. Especially that he is likely writing about factory equipment and not muddy dirt movers... yea... thank you for humoring me. Now I need to figure out why someone would reconfigure the fuel lines in my machine. Or actually, I don't need to figure out anything, I just need to un reconfigure. UGH!
just a further note, some hydraulic systems use a charge pump to supply oil under pressure to an axial piston pump ie hydrostatic drive systems and other closed centre variable displacement pump systems