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  1. Nutzman

    SKF Bearing identification

    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...
  2. Nutzman

    Centrifugal pumps running in parallel, one pump with high vibration

    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...
  3. Nutzman

    How is AI being used in your Piping career?

    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...
  4. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    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...
  5. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    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...
  6. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    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...
  7. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    Especially not when you knee deep.....[flush]
  8. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    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.
  9. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    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...
  10. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    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...
  11. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    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...
  12. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    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...
  13. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    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 -...
  14. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    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...
  15. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    Wondered why I could not see it
  16. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    Hi LittleInch, Thanks for coming back to me. Attached is a snapshot of the drywell/wetwell. In this instance the pipe diameter has gone form 100 to 200mm. Essentially what should have been done, was the wall, should have been core drilled to suit the height of the 200mm bellmouth clearance...
  17. Nutzman

    Wastewater Wetwell bellmouth annular velocity

    Hi all, I have a number of sites where the pipework was sized to cater for a flow on the day. Thanks to growing populations, the station needs to be upgraded. It's easy to increase pump and pipe sizes "in-station" to cater for the increased flows. However what is often ignored is the pipework...
  18. Nutzman

    Pipeline design with pump station and gravity flow

    As Littleinch states, Why drain the line? Bury it. I did a 2.6km 300mm PE lined steel pipe, surface laid (mining tailings disposal operation), with a temperature range of 5-50 deg C. We ended up installing expansion loops. nightmare of a design. Another downside for HDPE lines, has the maximum...
  19. Nutzman

    balanced impeller - Slurry Pump Mining

    Hi all, What is the impeller material? Hi Chrome or rubber lined? Either way, based on the design of the AH casing, you can access "half" the impeller, with the "cover plate" removed. Meaning you not able to do a field balance. But the bigger question is what is creating the imbalance? Wear on...
  20. Nutzman

    Parallel pipe

    MJC, Thank you for the support. We have various packages within the company, But the boss's oly allow access by certain staff. (The trained kind). Admittedly unless you use a package on a regular basis you quickly lose touch with it. Excel is a perfect example. However, no matter how fancy a...

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