Hi all,
From ancient memory, the first digit "5" designates a thrust bearing. The last digit "34" gives the shaft size (5 x the last number = shaft size in mm). However 2 shaft sizes are listed above, 170 and 172mm. This will decide which Thrust face will be mounted on the shaft and the other...
Hi all,
Looking at the 3D image (plan view), it would appear that the 10" takeoff's from the 18" header, come off on the (18" horizontal) centerline?
Why the suction lines were designed with 2 x 90 deg bends, is not evident.
The reducers before the pump. Are they concentric or eccentric?
Reason...
The Two companies I work for (International companies), have both blocked access to ChatGPT and Bing Copilot, based on the comment "we are reviewing the AI in terms of the companies requirements....". I have used both the above to provide engineering calculations. AI comes back with a list of...
The small gap between the floor of the sump and the underside of the bellmouth is designed to create high velocity in order to prevent solids from accumulating on the sump floor. You don't want solid buildup and a slump, thereby choking the pump.
That's the reason why one cannot extend the pipe...
Littleinch,
Very well expressed. And as you state the diagram is for air, but the same principle applies to liquid.
To add to my problem, there is a 90 deg bend at the Mach 0.237 mark. So another change of direction and more turbulence. Then a change in diameter (100 to 200mm) and then the flow...
Hi all,
Many thanks for your collective input. Having perused all the information, it has become a little more confusing.
Based on the above, the thinking has been to calculate the velocity at the "cylinder periphery" of the bell mouth.
However in the Hydraulic institute document mentioned above...
Hi Littleinch,
The product is sewage. So any form of flow conditioning is going to block up.
The pump supplier, has a trolley mount horizontal version. But then we got to modify the discharge pipework.
Hi Bimr,
Thanks for that input.
As per the image posted earlier, the site was a wetwell/drywell installation.
On further investigation it appears that although the line velocity in the pipeline through the wall is within the above limits, the lack of 5 to 10 times pipe diameter straight before...
Hi George,
Many thanks for that guidance. I had a copy of the spec and had perused said document. It's interesting to note that the clearance between the underside of the bellmouth and floor is listed as 0.3D to 0.5D. Whereas other literature (possibly '70-'80's) state 0.2 to 0.4D.
But the...
Hi Snickster,
I managed to create a dual Imperial/Metric spreadsheet. Once I got it into a digestable format, I note that your calculations (velocity across bellmounth)is based on the the difference of flow? Namely 200 and 450 GPM.
I'm essentially looking for a velocity for the old and new...
Hi Littleinch,
I agree with your thinking. As we all know, the flow velocity in a pipe is highest at the centerline and lowest at the inner pipe surface. So I trust the same principle will apply to the imaginary cylinder scenario.
Essentially what i am trying to determine is the increased...
Hi Artisi,
Unfortunately this is an old installation. So I've no clue what the original flow should have been.
But taking a guess on a "middle of road" line velocity in the 100mm line ~1.25 m/s. (understanding the self cleansing velocity parameters in the waste water industry are 0.75m/s -...
Hi Snickster,
Many thanks for your thoughts. I had been thinking along similar lines. My thinking was that, if I took a sheet of plastic and wrapped it around the perimeter (circumference) of the bellmouth and cut the sheet off at the height of the bellmouth. Then unwrapped the sheet, I would...
