Effects on SAE 10 vs. SAE 12 ports

[Soulsolutions2020]

I am building a forging press and I am using a 5" bore with a 2" rod, 8" stroke cylinder with clevis ends. The original design called for a SAE12 ported cylinder double action. I found one exactly the same except for the ports are SAE10 so I assume that is a 1/2" vs. a 3/4" fitting. Can anyone tell me if this will affect the power of the ram or speed or both?

My pump and motor combination are running at 3200 RPM CW, with an output of 1.5 ICD

 

[RickB]

actually the difference is 5/8" vs 3/4". If the design flow is above the accepted flow rate for a -10 fitting then theoretically you will have a speed reduction and pressure drop across the ports and fittings screwed into them.

 

[ericm979]

If SAE10 is small enough to restrict flow, it'd affect speed but not force. You can find rule of thumb GPM limits for the different fixture size.

Flow restriction is a function of diameter and length of the restricted area. So if SAE10 is a restriction, keeping everything else larger will minimize the flow reduction.

 

[RickB]

If SAE10 is small enough to restrict flow, it'd affect speed but not force. You can find rule of thumb GPM limits for the different fixture size.

Flow restriction is a function of diameter and length of the restricted area. So if SAE10 is a restriction, keeping everything else larger will minimize the flow reduction.

Restrictions cause pressure drop across the restricted area. Pressure loss reduces force.

 

[oldnslo]

If my math is correct your pump will produce approximately 20 GPM. I would use step size fittings and run #12 hose especially on the cap end since you will have higher return flow when retracting.

I doubt that you would notice the difference between #10 & #12 ports but like others state double check flow recommendations for hose size. Target is to keep oil velocity in 10 -15 feet per second range.

 

[LD1]

Im figuring that as 20gpm as well.

Hose sizing for return, suction, and supply are all based on the fluids "feet per second" inside the line.

With 5/8" hose, and 20gmp.....you are right at the suggested maximum of 25fps. At 3/4" it gives a much better ~17fps.

Oldnslo is correct though. When retracting....you are gonna try to force MORE than 20gpm out of the base port. With a 2" rod it will be closer to 24gmp coming out of the base port on retract. Which is ~30fps for the fluid in the lines. A little more than what is considered "acceptable". I believe it will slow down the operation....but whether its noticeable is debatable.

Can you not find a 5" cylinder with 3/4" ports?

 

[mcfarmall]

Restrictions cause pressure drop across the restricted area. Pressure loss reduces force.

The key here being "across the restricted area". Once past the restriction, the cylinder will continue to fill with fluid and the pressure will rise to the system pressure setpoint exerting the same force upon the actuator. You will lose speed as the cylinder extends or retracts but will have the same FORCE as with the bigger port size.