Log Splitter Hydraulic Filter, Gauge Questions

[Mace Canute]

Putting a filter in the suction line runs the high risk of cavitating the pump (cavitation is very damaging). There are a few rare exceptions to this but in general you should install the filter on the return line to the tank. An 'in tank' suction line strainer is not needed either. Make sure the tank is clean first and then make sure you don't drop any crap into it at any times afterwards. If you want a strainer, get one that sits in the fill hole. Much more practical.

 

[AKKAMAAN]

My question is related to the definition of "LOW PRESSURE"...if low pressure on the supply side is between the tank and pump, then where does it transition from high pressure to low on the return side? When it leaves the valve body or somewhere around the return line filter?

The transition between high and low pressure is actually inside the control valve, but count the tank port on the control valve is the transition point. 150psi is "high pressure" in a return line (basically in the filter)....all of it created by resistance in return filter, hose and fittings.
Make sure get a return filter with a flow by pass valve, pressure setting usually around 15-50 psi....

 

[AKKAMAAN]

If you want a strainer, get one that sits in the fill hole. Much more practical.

+1 :thumbsup:

 

[J_J]

Over engineering, and I know what the charts say. I really don't understand the need to go larger that the pump inlet and outlet and valve inlet and outlet size. I could see increasing the size on a long run, but on about 6 ft of hose. Common sense would dictate they match the ports, plus the increased cost of larger fittings and hoses has to be taken into account. I think I would make all the hose the same, 3/4 in except for the 1 in suction hose.

 

[AKKAMAAN]

Over engineering, and I know what the charts say. I really don't understand the need to go larger that the pump inlet and outlet and valve inlet and outlet size. I could see increasing the size on a long run, but on about 6 ft of hose. Common sense would dictate they match the ports, plus the increased cost of larger fittings and hoses has to be taken into account. I think I would make all the hose the same, 3/4 in except for the 1 in suction hose.

It is possible to cut some corners when designing a system, if you know the "risks"....
On the pressure side of a fixed displacement pump, undersizing will create pressure drop during flow (no flow no pressure drop), but entire flow will still get to destination, if some of the flow is not partially diverted.

Pressure drop is a POTENTIAL source of TO MUCH HEAT. TO MUCH, depends on, cooling capacity, and cycle frequency.
So I agree that there can be some unnecessary "over engineering".

Cost of lost energy and cooling vs cost of larger sized hoses, have to be calculated.
In some low frequency cycled system we can cut the corner with some "common sense", if we KNOW we have that common sense.

One should always try to design for as much laminar flow as possible
Smaller size fittings and hoses, increases fluid velocity.
When fluid velocity increases, the turbulence increases (Reynolds number is at 2300 or higher)
Turbulent flow increase resistance and pressure
Slowing down velocity in a larger hose between to smaller sized ports, will reduce pressure loss, PERIOD!
Do we need that reduction of pressure loss?? Thats another question....On a suction line, definitely YES!


The suction side is different, because there is a limited pressure to drive the fluid through the suction line, the 14.7psi atmospheric pressure.


Homework 1: This addition of total restriction on the suction side, is a little bigger when extending a DA cylinder than when retracting the same. Why is that??

Homework 2: Why would it make sense to have a larger sized line between the control valve port and the capped side port of a DA cylinder??

 

[LanceH]

Thanks JJ. I'll put a tee on the inbound side of the valve body.

This is the type I was going to go with: Valley Instrument 2 1/2in. Stainless Steel Glycerin Gauge — 0-3000 PSI | Filled Gauges | Northern Tool + Equipment

The picture must just be a stock image. It is a 0-3000 psi gauge and its glycerin filled which I read should be better suited for my log splitter application-which has lots of vibration.

Is 3000 psi too big or not enough? I chose this because my pump max output is 3000 psi and I didnt think the system pressure would be larger than this.

 

[ptexer]

I think Mace Canute statement was very well written and accurate. Akkamaan did another great post. I would just like to say I believe strainers in tank or filters on suction side have the potential for more damage than benefit.

 

[LanceH]

Thanks JJ. I'll put a tee on the inbound side of the valve body.

This is the type I was going to go with: Valley Instrument 2 1/2in. Stainless Steel Glycerin Gauge 0-3000 PSI | Filled Gauges | Northern Tool + Equipment

The picture must just be a stock image. It is a 0-3000 psi gauge and its glycerin filled which I read should be better suited for my log splitter application-which has lots of vibration.

Is 3000 psi too big or not enough? I chose this because my pump max output is 3000 psi and I didnt think the system pressure would be larger than this.

About the max pressure that the gauge will read...I'm wondering if my barnes 16gpm pump will ever be able to create anything over 3000 psi? I just want to know if a gauge that reads a max pressure of 3000psi is good or if i need to get the next one up which is 5000psi.

Any advice?

 

[J_J]

You may see pressure spikes above 3000 psi, but most people use the 3000 psi gage.

16 GPM two stage pump.

3000 PSI max
4000 RPM max
First stage 16 GPM @ 650 PSI
Second stage 4 GPM @ 2500 PSI
16 GPM @ 3600 RPM