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Recent content by daveboy

  1. daveboy

    API 16C Choke and Kill Manifold - Pressure Integrity

    Ok no response. I will try the API standards forum
  2. daveboy

    API 16C Choke and Kill Manifold

    I would appreciate some of your opinions on the below. We are quoting a API 16C manifold.The design is 10K upstream of the chokes 5K downstream of the chokes. Two hydraulic chokes and one manual choke. From the chokes all connections go to a buffer chamber rated to 5K. So all ok. Our customer...
  3. daveboy

    API 16C Choke and Kill Manifold - Pressure Integrity

    I would appreciate some of your opinions on the below We are quoting a API 16C manifold. The design is 10K upstream of the chokes 5K downstream of the chokes. Two hydraulic chokes and one manual choke. From the chokes all connections go to a buffer chamber rated to 5K. So all ok. Our customer...
  4. daveboy

    pump impeller

    You need to take care on higher energy double suction impellers as there may be biased wear rings to ensure thrust is always in one direction therefore it only fits oneway to fit the mating parts.
  5. daveboy

    Low-friction coating to improve pumping efficiency?

    What you are trying to do is reduce the surface roughness to reduce disk friction and change the vortexing in the side wall gap to reduce leakage and give an overall improvement in efficency. As with flow in pipes it is Reynolds number dependant. The paper below gives you some theoretical and...
  6. daveboy

    Balancing Axial Thrust Devices

    When using a balance disk you tend to also include a small bump stop in the NDE bearing housing which allows contact during transients without damage. A balance disk is effectivley a self actuating valve, as pressure builds in the gap to a level that the pressure over the disk area exceeds the...
  7. daveboy

    Finding Shaft Critical Speed

    I haven't tried this with COSMOS yet but I used to do this a lot with Ansys designspace (not very successsfully ) and with Ansys mechanical. Looking at the results from from the resonant frequency and the shaft critical speed they appears to be very similiar and I would suspect although I am...
  8. daveboy

    Assembly Mate

    For mating origins of parts to assembly origins If you drag the part from the part window into the assembly and hover over the assembly origin with the mouse pointer before letting go of the mouse button 2 arrows appear. When this happens let go of the mouse button and the part is mated to...
  9. daveboy

    Hoop Stress for 'inner tube-type' design

    I'm from Scotland! I guess your modelling the inner tube alone with a pressure on the inside and no outer wall support from the tire etc and if you apply a constraint to the model it doesn't work correctly and if you don't apply any constraint then you get messages something like it is under...
  10. daveboy

    Hoop Stress for 'inner tube-type' design

    When you say it doesn't want to work what do you mean - is it because it's under restrained, it won't mesh or some other error? Is this like a pipe inner tube / liner (i.e. linear) or like a tyre inner tube (i.e. circular)? Can you advise on what you want to achieve as there maybe alternatives...
  11. daveboy

    PUMP MATERIALS FOR FOOD PRODUCTS

    What Whizz suggests is fairly common practice within the potable water industry, however the anti corrosive coatings have to be pre approved by the relevant authorities for use with the specific fluid this is usally acheived by testing. I guess it will be the same if not more stringent in the...
  12. daveboy

    Welded Frames

    I have a framework constructed from plate and I am trying to use Cosmos designer to evaluate stresses at joints to size the welds. I can select the lines between plates to get stresses in the x, y and z directions and then resolve these to get a stress at the joint which in turn I can you to...
  13. daveboy

    Conveyor head pulley bearing demonstrating short MTBF's.

    Have you sent your failed bearings back to SKF and asked them to identify the cause of failure. SKF a very good at making an assesment of probably caase of failure from looking at broken bearing parts. Are the loads as per design, has anything changed? The SKF guy and probably any bearing...
  14. daveboy

    Excel program for Plate Stress Analysis

    You will find a paper with an alternative method here http://www.ce.berkeley.edu/~rlt/reports/clamp.pdf I haven't tried this method. You will also find a spreadsheet for a simply supported rectangualr plate here http://pergatory.mit.edu/2.007/software_tools/spreadsheets.html Not quite what...
  15. daveboy

    mechanical seal substitution

    Some words of concern I have had a lot of experience in the past few years of purchasing departments selecting equivelant seals from alternative supplier as they are cheaper than the specified seals without paying attention to all the limitations or having any engineering input and relying...

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