Strainer or Larger Suction line?

[David Devuono]

I have a 10 gallon tank with a 1 1/4 NPT suction line port. The available strainers drop the outlet to 3/4 NPT. Would it be better to stick with 1 1/4 suction line and leave out a tank strainer or move to a smaller line. Target peak flow is 15-18 GPM,

I probably already know the answer. So if it is to weld in a larger port flange, would a 1 1/2 in port with a strainer that has a 1 inch NPT outlet be large enough for my target peak flow?

My pump has a 20 ORB inlet. The issue I have with welding in a new port flange, the existing outlet has about 1" of threaded surface with which to seal with Teflon tape. The weld in port flanges have about 3/8 " of thread. Will I be able to seal this connection?

 

[AKKAMAAN]

I have a 10 gallon tank with a 1 1/4 NPT suction line port. The available strainers drop the outlet to 3/4 NPT. Would it be better to stick with 1 1/4 suction line and leave out a tank strainer or move to a smaller line. Target peak flow is 15-18 GPM,

I probably already know the answer. So if it is to weld in a larger port flange, would a 1 1/2 in port with a strainer that has a 1 inch NPT outlet be large enough for my target peak flow?

My pump has a 20 ORB inlet. The issue I have with welding in a new port flange, the existing outlet has about 1" of threaded surface with which to seal with Teflon tape. The weld in port flanges have about 3/8 " of thread. Will I be able to seal this connection?

Or fill cap strainer....

 

[rswyan]

The weld in port flanges have about 3/8 " of thread. Will I be able to seal this connection?

Dave,

Check page 97 of McMaster-Carr's online catalog - they show the height on 1 1/2" weld-in pipe bung as being 3/4" .... so ya might get 1/2" of thread out of it .....

 

[rustyrigs]

I haven't finished resding yet, BUT!! Stop right there!! Don't use teflon tape on hydraulics please....

 

[IceStationZebra]

Stop right there!! Don't use teflon tape on hydraulics please....

I was going to say the same thing!

And as far as sizing a pump inlet goes, you didn't provide enough data to really say yes or no. Oil viscosity, pump flow, what is the coldest temp you expect when starting system, etc.

In general you can't go too big on pump inlets. If it has a -20 inlet you should try to stick with -20, especially if you insist on using an inlet strainer. If you ditch the strainer you might be able to drop down to a -16 depending on the system particulars.

ISZ

 

[David Devuono]

Sounds like I have to pick up some special tape. I used Teflon on the NPT connections to my Massey, never leaked so must be a issue with contamination?

 

[rswyan]

Sounds like I have to pick up some special tape.

Nope - what you need is teflon pipe dope - it's a paste :thumbsup: (Home Depot, Lowes, Menards, hardware store, etc.)

I used Teflon on the NPT connections to my Massey, never leaked so must be a issue with contamination?

Leaking/contamination isn't the problem - teflon tape has a way shredding itself as you tighten the fittings - the shreds get inside the hydraulic system and have a way of plugging up the works.

 

[AKKAMAAN]

Nope - what you need is teflon pipe dope - it's a paste :thumbsup: (Home Depot, Lowes, Menards, hardware store, etc.)


Leaking/contamination isn't the problem - teflon tape has a way shredding itself as you tighten the fittings - the shreds get inside the hydraulic system and have a way of plugging up the works.

I agree that Teflon tape can "screw" up...especially if one do not know how to wind/screw that tape on the male fitting, it is definitely at least 50% chance to fail...just from the direction of winding the tape....

>only use it on tapered threads

>don't cover the front/top of the threads

>Teflon need to be properly stretched

>wind the Teflon tape on, by turning the male threads the way you screw it into the female....make sense??

 

[mmurphy]

I agree that Teflon tape can "screw" up...especially if one do not know how to wind/screw that tape on the male fitting, it is definitely at least 50% chance to fail...just from the direction of winding the tape....

>only use it on tapered threads

>don't cover the front/top of the threads

>Teflon need to be properly stretched

>wind the Teflon tape on, by turning the male threads the way you screw it into the female....make sense??

LOL!! We had a guy we kept giving a rough time about sending him to CEU (continuing education units) on how to rap teflon tape around threads. He could never remember what way to go.

 

[KWentling]

I have no idea what your application is, but a 10 gallon reservoir for 15-18 gpm is awfully small. You want at least equal reservoir volume as pump output and twice is better. That would explain why the outlet port on your tank is the size it is. It was not designed for that big of a pump.

Kim

 

[IceStationZebra]

Kim, I don't disagree about the reservoir size though I will say that off-road equipment breaks that old rule-of-thumb all the time. I am an engineer and have worked for several OEM's and on one project it was only 1/4-1/3 the capacity of the pump at full RPM. Industrial applications still tend to stick with the 1-2x pump flow, or more.

The biggest issue is aeration. You would be surprised how long it can take air to rise out of the hyd oil. We cut the side out of a reservoir and put a piece of plexiglass on. We ran the machine till it was hot then shut it off. It took a good 20 minutes for most of the bubbles to rise 18".

ISZ

 

[David Devuono]

I understand the 2-3 x rule for tank size but realistically, I don't want to carry 200 lbs of hydraulic fluid on a 1000 lb machine. I have a large cooler to take care of the heat. Besides, I don't even know if this thing will move. While I bought a weld on fitting to install a larger filter screen, I think I will go without for now and use a 1 1/4 id suction hose.

 

[David Devuono]

pump mounted under engine tray

 

[J_J]

Are you saying that you have a 18 GPM pump? A pump that size at 3000 psi, will need a 37 HP engine.

My Power-Trac, will pump about 22 GPM using all three pumps, and needs all of the 45 HP

My hydraulic tank holds 20 gal and the machine has a hyd radiator and fan.

 

[David Devuono]

Interesting that when I first indicated I had a 10GPM pump I was told in need 15hp. Then I see that someone using a 28gpm pump for a large log splitter needs 16HP? I realize a log splitter is mostly filling an unloaded cylinder and just a short high pressure cycle. I have a pump that is rated for 2500PSI and 10GPM at 1000 RPM (3,000 RPM max). I will be running this pump at 1650 RPM (Engine govnd at 3300 RPM) via 2:1 reduction. So in Theory thats about 16.5 GPM. My motors are rated for 2450PSI. I have no experience with hydraulic motors but the specs say it will produce 3,000 inch pounds intermittently. so if I run my system at 2450 PSI two motors will produce 500 ft lbs torque into 10 inch dia wheels. Anyway, I have seen so many different opinions, I will just have to try things. I will start with 2000 PSI and work my way up to 2450 if necessary to make this thing turn. If it still does not have enough power, I will consider further reduction between motor and drive wheel. If it lugs my 27hp engine but otherwise has power, I will change my engine pully.

 

[KWentling]

Simple formula: GPMxPSI÷1714=HP. Your engine should be big enough.

Kim

 

[Ford tractor]

If I understand, you are trying to put a strainer in the return line at the reservoir tank --Yes?

If so, I would ditch the strainer, keep the larger line diameter and put a filter with a bypass in the housing set around 25psi on the return instead. 5 micron media and a 8" canister would be fine.

Strainers just catch big things like marbles, but it's the little specs of stuff that ruin the pump, motors etc.

 

[David Devuono]

Strainer was to be on the suction line. It would also have a remote filter on the return line. I will probably take AKKAMAAN's advise and look for a filler strainer. (now I have various Strainers and weld on ports in my collection)

 

[J_J]

David,

Can you tell us the cu in of the hyd motors, and pump, and the max rpm?

Is that one pump for each motor, or one pump for both motors.