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  1. scalleke

    Seal between PEEK and Duplex (other stainless), Titanium

    I can see the problem here. A static connection will not work. The elasticity limits of the materials are too dissimilar. Every time a machanical connection is made the Peek will be stressed over the elasticity limit and be deformed. The Peek will also Flow after being tightened so a...
  2. scalleke

    Dual mechanical seals

    So can someone tell me why a double mechanical seal is required here? Hydrocarbons in a tank farm? Use a single seal and vent the vaporised leakage off to the top (vapour section) of the tanks. To reduce the leakage a tandem seal could be used. Just connect the cavity between the first and...
  3. scalleke

    suggestion for low pressure water, rotating shaft seal

    Seems you have made the choice already. Mechanical seals may seem like overkill but they are the only thing that will give you the service life that you need and if you select them double with a barrier fluid they will work as well on the vacuum as with pressure in the pump. scalleke
  4. scalleke

    Gate Valve Repair

    Usually the wedge seating surface is ground. This is easier as any surface grinding machine can be used for this purpose. What is difficult is that the seating surface on the wedge must be lapped after grinding on a lapping plate. Do note that the wedge is heavier on the top section and that...
  5. scalleke

    Fire Safe Ball Valves

    I used to test valves acc to API 607 for a living. Polymeric seals melt during the fire and a secondary metallic seal takes over. In the case of the valves that I tested the valves were designed with a "Fire Lip", a sharp edge in the seat seating area. The ball would seat on the fire lip once...
  6. scalleke

    Gate Valve Repair

    Make sure the seat faces are properly lapped. Make sure the wedge surfaces are nicely lapped Place the wedge in the valve solidly down and against one of the seats. With feeler gauges determine the gap between the opposite seat and the wedge surface. Also determine the largest gap postion on...
  7. scalleke

    Equalize Pressure for 18" Ball Valve

    Whether the valve will lock up due to internal pressure depends on the balance of the seats. Something that the manufacturer will know. Best Regards, Scalleke
  8. scalleke

    pressure loss of 82psi to 40psi

    "I believe this building is the last one on the line that is dead ended." If this is indeed the case, then all other users on the same line will have an influence on the pressure at the end of the line... right. I see two issues: One the consumption of the other users on the line and two, the...
  9. scalleke

    Double Volute vs Single Volute

    What will be the system resistive curve and what will be the new pump performance curve. You have the advantage of knowing the system perfectly well and this seems to me an opportunity to make sure that you get a pump that is perfectly suited to your system. Yes, single volutes have more...
  10. scalleke

    Design advise on using a vaporizer to pump liquid.

    Duane365, Question I have is "What is the vapour that you have above the liquid phase in the vessel?". I do believe you are on the right track. Heating up the main volume of liquid that you have gives the nasty side effect that all the liquid you are trying to move is being heated up ( I...
  11. scalleke

    leaking seals

    What does the shaft surface look like? If the initial seals have been operating for a longer time on the same position on the shaft the shaft position might have gotten erroded. In that case reface the shaft surface or position the seals in a slightly different unaffexted area of the shaft...
  12. scalleke

    Seal to seal-off gases

    As long ar your gland is static you can use helicoflex metal o-rings. Garlock-Helicoflex scalleke
  13. scalleke

    Mechanical Seal for Latex

    Depending on the mixture that you are using there must be a water contamination level that you can tolerate. You should use double seals water flushed. That will give you a little water contamination, but your seal internals will get all gummed up as they are not flushed with water. My...
  14. scalleke

    high rpm (23K) mechanical seal

    Contact John Crane for this. They routinely make seals for these conditions. A seal they make for similar conditions is used in Sundyne high speed gearboxes up to 35000 RPM. And yes, the item is low cost. (considering the service conditions) Best regards. Scalleke
  15. scalleke

    Modified Francis Vane Impeller

    smckennz, I second your statement. Real life is far more complex than the affinity laws lead us to believe. That is why so many times I mention trial and error approach. In an impeller trim case I would simply calculate the trim. Perform anywhere from 50% to 75%, assemble and test to see...
  16. scalleke

    NPSHA pumping two liquid phases

    Onepotato, I believe you are looking at too great a detail. Since there is uncertainty about whether the light fraction will separate and flash off simply take the NPSHA of the lightest fraction as the NPSHA for the system and spec the pump out as such. 2 m NPSHA should not be a problem...
  17. scalleke

    High Pressure Ball Valves

    Metal seated or soft seated? Any manufacturer that makes ball valves in the pressure classes that you mention should be OK. However, think about the intended service your allowable leakage and the test specifications that will be used!!! Make sure you specify a test spec that will prove...
  18. scalleke

    Modified Francis Vane Impeller

    A trim will follow affinity laws but not if one trims too great a percentage. If the distance between the impeller outlet and the volute gets to be too great the liquid will start to recirculate in the pump and this will cause additional losses. In any case you better ask the manufacturer to...
  19. scalleke

    Halogen Bulb

    A 250 W Halogen bulb will give of a certain no of lumens. 1715 lumen = 1 KW/m^2. The Al relector will reflect part of the energy and absorb some to heat itself up. The reflection / absorbtion ratio will depend on many factors such as the surface treatment of the Al reflector. HOw hot the...
  20. scalleke

    Headline: "Dollar Crumbles to Record Low Vs Euro". Bad or good?

    Is the value of a currency an indication of how attractive the economy of a country is? In general Yes, but in this case NO. The fall of the US dollar is not a consequence of a poor US economy it is a simple consequence of thwe fact that the US government is in fact borrowing way too much...

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