adding a hydraulic filter

cmcgalla · Mar 21, 2014

Hello, I have an older backhoe that I want to add a filter to. Currently it does have a little Y-strainer, but I want a spin on cartridge filter like this one:

http://www.surpluscenter.com/Brands/Zinga/3-4-NPT-9-GPM-FA1112-25-SUCTION-FILTER-W-GAUGE-9-077-A.axd

Should I add a filter in the suction line or return line?

The product talks about full flow filtering up to bypass cracking point, partial filtering beyond.

What is the bypass cracking point?

As always thanks for the input, this forum is the BEST on the internet.

Zeek

CH(upstate,NY) · Mar 21, 2014

Return line.

ohiojim · Mar 21, 2014

it is usually put in return line and the cracking point is where the relief valve opens and lets some of the fluid bypass to relieve pressure, any fluid that bypasses will be unfiltered

chevdud97 · Mar 21, 2014

CH is right. if the filter is put on the suction it will create cavitation on the pump and cause damage.

bill mart · Mar 21, 2014

this filter is designed for the suction line (says that in the description) Bill
suction filter

cmcgalla · Mar 21, 2014

My question is answered, I will put the filter in the return line. How do I know where my relief valve is? Also the return line is about 1-1/4" in diameter, and I see that surplus center has a 1-1/4" return line filter, would I have to get hoses made for that? I assume the return line pressure is too great for a barbed connector with hose clamps. can post some pics of the set up later today.

Thanks

farmer boy · Mar 21, 2014

Hose clamps are often used for the filter on the return side. Just find some oil resistant line that's 1-1/4" i.d.

bill mart · Mar 21, 2014

if all that"s true about putting a filter on the suction side why do they sell them ? just asking. Bill

ohiojim · Mar 21, 2014

return line seldom gets any real pressure, so you can use the barbed fitting and hose clamps and unless the filter becomes clogged it will never bypass...

Bob · Mar 21, 2014

The relief valve in question here is either in the filter itself or in the filter "head".

It opens when there is a few psi of pressure (there will be a "spec" for your chosen unit) across the filter due to the oil being cold or the filter becoming "plugged".

J. W. Schwiebert · Mar 21, 2014

Also the flow capacity of the filter should be from 1-1/2 to 2 times pump output. When you let a large cylinder down quickly the flow is a lot more than pump output.

Steve@Advance · Mar 21, 2014

I've always seen a suction filter down inside the tank, a fine screen mesh to protect the pump and valves from large debris.

The return filter is a pleated paper disposable filter to help keep the oil clean.

J. W. Schwiebert · Mar 21, 2014

That in correct terms is a strainer. The size of it is measured by the mesh size. Also for pumps I have never seen anyone recommend a filter that does not filter down to 10 micron for a piston pump and 30 micron is a fairly standard number for return line filters.

Anonymous-0 · Mar 22, 2014

There's a difference between a suction strainer and a filter. Any filter I've ever seen for the outlet side of the pump won't handle much volume. Return side is most common.

adding a hydraulic filter

cmcgalla

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CH(upstate,NY)

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ohiojim

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chevdud97

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bill mart

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cmcgalla

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farmer boy

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bill mart

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ohiojim

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Bob

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J. W. Schwiebert

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Steve@Advance

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J. W. Schwiebert

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Anonymous-0

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