I bought a filter cart for cleaning up the hydraulics on my equipment. The guy I bought it from was using some sort of air pump to run it and it crapped out on him so he installed a new motor/pump on it. It still needed the hoses installed so I ran it into town and had the hose shop finish hooking everything up. Went to use it but it built up over 100 psi in only a few seconds blowing out the o-ring on the canister lid. I started checking online and I believe the pump he installed is way over spec. for what the Harvard 1002 element is designed to take. The pump has a relief built in that is set somewhere around 120 psi. The cart can’t go over 80 psi. It does have the ball valves just before entering the housing so I was wondering if I could just close the valve off to reduce the flow. Not sure if this will work. Would the pump get to hot when it went over relief? Would it be better to look for a smaller pump? Appreciate any advice. Thanks
Looks to me like the acorn nut on the side of the pump probably covers an adjustable pressure relief screw.
Are the filters plumbed in series as oil going to one and then the other? Is there only one filter in each canister? Most of the carts I've worked with that have one filter in each canister feed both filters in parallel. The other issue is that you should measure pressure differential across the filter instead of just the inlet pressure. If you have 100 PSI going in and 80 PSI going out, then you have 20 PSI on the filter and you need to look for another reason for the high pressure on the inlet. Are you pumping cold oil? The volume of flow of the pump against the volume of flow the filter is rated for is the key spec. How fast is the electric motor turning?
Hi John, Correct on one filer in each canister plumbed parallel. The pressure gauge is on top of one of the canisters before going through media. I checked the Harvard 1002 filter spec showing flow rate of about 11 litres per minute at 150 degrees. I think the pump puts out more than double that. This is based off 1800 rpm motor spec. The motor on my unit says it’s 1725 rpm. I isolated one canister without filter filling from one 5 gallon bucket to another but only had 3 gallons of oil so I couldn’t run a long test. It moved that amount in less than 15 seconds. It seems to me I have to much pump but I may be missing something. Thanks!
I think you are right. Three gallons in 15 seconds is about 12 gallons a minute. A rough calculation I think hits at about 50 liters a minute. What is the particle size rating on the filters? Do you know if you have a barrier filter or a labyrinth filter?
The filter goes down to 1 micron. It does not have a labyrinth filter. I believe the new units come from the factory have a pre-filter and recirculation valve. This one I just ran hose straight from hydraulic tank to inlet of pump. I wanted to see if everything was working ok before adding a pre filter. The oil was warm when I tried it out. Not 150 degrees though.
I hope you can see the page well enough.
That's a tight filter and I bet your equipment had at least 15 weight oil in it
Tight filter for sure. 46W oil. Oil sample from lab shows Viscosity at 40C at 33.7 centistokes. I'm hoping to clean up the hydraulics well. The tank on the machine holds only half the entire system capacity so I want to get as much junk out before I change out oil.
I'd throw a 5 micron filter and try it
Pulled the relief out and will try to back it off all the way and see where things end up. I’m going to change out oil in tank before I try again.
If you are planning on using a filter element rated at 1-micron absolute then IMHO then an AW46 oil would need to be heated to at least 60 DegC (probably more) to pass through the filter efficiently without running into restricted flow/overpressure problems. Even then I would say that it's not guaranteed to work. Note that the filter data sheet only says it's rated for passing oils up to ISO 32 viscosity, so if you are trying to push an ISO 46 through it that's already outside the spec chart. So you would you really need the oil darn hot for the filter to have a remote chance of working. I haven't looked but does the filter manufacturer offer the same element in either 2 or 4-micron absolute ratings.? What do the flow vs temp charts look like for them.? Are they rated for ISO 46 oils.?
Yes I was hoping to get down to 1 micron. When I picked up the filters up in Edmonton I didn’t know what I know now. I should have grabbed the 1004 element that gives more flow. Same micron rating at 1. I’ll have to check to see what other filter options they have. I changed out the oil but I’m still short around 40-60 litres so will have to run into town tomorrow and get more oil. I’ll get it up to operating temp and try filtering again. I’ll plumb in a regulation valve if needed. Thanks Nige.
TBH with hydraulic oil you could easily go to a 4/5-micron (abs) filter and you would still get the oil far cleaner than OEM fill oil cleanliness spec. The smallest particle size that the ISO4401 Cleaniliness Standard measures is 4-micron. Question: What are you planning on doing to confirm the efficiency of your cleaning process.? I assume you're not thinking of shelling out $35k for a portable particle counter. https://www.pamas.de/particle-counters/products-by-name/pamas-s40.html
I'll check to see what other filters are available. I used Finning SOS for my oil analysis. I'll grab another sample after say 50 hours to see what we can achieve. I think they are charging around $40.00 Canadian for particle count. Thank You.
Got the oil changed out and hen went and turned the compost pile for about an hour. Nice and warm oil. Hook d up the cart and barely opened the valves into the canister watching the pressure. Valves are opened around half way with 30 psi. I’m guessing my flow to be around 70 litres/minute or 15 gal/minute. That seems not bad.