GRavity Feed to Mud pumps

[JonnyWill]

Hi all. I have an existing piping & pump process system but will be updated to new design. There is a specification which states that “The HP mud pumps shall be located to allow gravity feed from mud tanks in case of failure of super charge pumps. Supercharge pumps shall have gravity feed bypassing piping”
The present design supercharge pumps are based on 3x100% to supply 3x100% HP mud pumps. From the 4 mud tanks. The inlet manifold to supercharge pumps is located on the same main header from the tanks. Discharge from supercharge pumps goes to the respective HP mud pumps. Should one of the supercharge pumps fail there is a bypass line from the tanks to the discharge of the supercharge pump, but the bypass can not guarantee the required NPSr to the HP mud pumps.

If there was a crossover on the discharge of the supercharge pumps there would not be a need for the gravity feed from the mud tanks. Is that acceptable?
Additionally is there aneed to have 3 supercharge pumps if we can get away with just 2?

 

[BigInch]

You first have to ask the question, why are there 3x3. Why wasn't the original desing 1x1, or 2x2? A 3x3 design would indicate a problem with chosing larger sized pumps, or it might indicate a need to have the ability to still run two, if one had broken down, or still run 1, if 2 were down. Be sure you're not changing the required standby/emergency role of the system before you decide to make those changes.

3 pumps on 2, assuming they were originally sized for 3 on 3 and the flowrates would not change in the new design, would not be a good match. Its puts 150% flow on each of the 2 pumps, which is probably well out of their operating range. The flowrates of the 2 pumps for the new design should be upped to 150% of what they are now with presumedly the same discharge heads in order to match the other 3 pumps. That could also drastically affect any required duplicity for emergency standby service, so again find out what the supposed advantage of the 3x3 configuration was before you change it.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[TenPenny]

Spec: The HP mud pumps shall be located to allow gravity feed from mud tanks in case of failure of super charge pumps

Your idea: If there was a crossover on the discharge of the supercharge pumps there would not be a need for the gravity feed from the mud tanks.

Is it acceptable? You'd have to ask the people who wrote the spec, because with your idea, you are not meeting the spec. It's pretty clear that the spec calls for gravity feed to the pumps. It doesn't offer any options, it's fairly cut and dried.