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Recent content by markboc

  1. markboc

    Flow stall after pipe drops down

    Thank you all again for your input. We made the decision on the design and will start ordering soon. As per 1503's simulation we felt comfortable of installing control valve in the Hx1 downleg. This should solve the pressure problem and help reduce flow over Hx1. We will also install a FCV...
  2. markboc

    Flow stall after pipe drops down

    Yes. From what I gathered from the documents, the pump is from 1980. RPM 1480, not sure if it's BEP but it's 85 % efficiency: head 60 m, Q 1050 m^3/h, power 195 kW (rated 260 kW) Thank you very much, again, greatly appreciated! I'd need to check that, at first glance even at 550 m^3 / h I...
  3. markboc

    Flow stall after pipe drops down

    Thank you very much! We're currently in the construction phase of other projects and that consumes quite a bit of my days currently. So bear with me if my response times are a little bit slower than usual. Orange = Distance in m Red = Temperature in °C The lengths are rough estimates, the...
  4. markboc

    Flow stall after pipe drops down

    Sorry for delayed response! I was preoccupied with other projects. Above what return pipe? I could see if we have a LI for the tank (probably). This was also one of the original ideas but to be flexible with changing operating conditions and the fact that the time frames in which can work on...
  5. markboc

    Flow stall after pipe drops down

    Thanks again for all the good input! Earlier you mentioned Bear with me here please, but I don't the woods from the trees. We should install a vent like in your sketch, got that. This will raise pressure to 0 gauge and prevent the vacuum. Then you talk about changing the leg A - B to 600 mm...
  6. markboc

    Flow stall after pipe drops down

    First of all thank you all for your valuable input! I didn't have access to my system over the weekend so I couldn't get you all the information earlier. I updated the diagram (please excuse that I mistakenly thought the Hxn were in series when they in fact were in parallel, but they are still...
  7. markboc

    Flow stall after pipe drops down

    What do you mean by cascade flow? I couldn't really find an explanation. This would mean V2 could be used to control the pressure in the system, I read from all the posts that this is not the case? I get that you can still get increased pressure depending on the pump curve and cv. Did your...
  8. markboc

    Flow stall after pipe drops down

    I'll adress the other questions raised in depth tomorrow. Just to clariy: There is no other flow control valve than V2. Currently V2 is a manual valve (flap?) and will be upgraded to an automatic rotary plug valve. Maybe this upgrade started the confusion that there maybe another flow control...
  9. markboc

    Flow stall after pipe drops down

    Thank you too! Yes, with the exisiting V2 we want to be able to supply less water in order to reduce the cooling duty of the heat exchangers. Flow is measured with inductive flow meters. My diagram is one single state of which I got the most information. Occasionally up to 1000 m^3 / h are...
  10. markboc

    Flow stall after pipe drops down

    Thank you very much 1503-44 for your indepth answer! So throttling V1 may actually help with the problem. Partial flow was the term I was looking for with stalling. What I took from your post is that it may be possible to find the sweet spot in throttling such that upstream pressure is...
  11. markboc

    Flow stall after pipe drops down

    Thank you all for your input! I also realized prior to looking back at this thread that my post may have been confusing and I wasn't wrong. Let's start again. This is a recirculating loop, the tank is vented if the symbol I drew there isn't clear. This is the current situation and I...
  12. markboc

    Flow stall after pipe drops down

    Hello, we have the following problem: A heat exchanger (15 m) is fed by a pump (0 m). It is a pipe network where other heat exchangers on parallel pipes are located much lower. The pressure gauges read low to negative pressures right before and behind the heat exchanger. Throttling behind the...
  13. markboc

    pipeline lowering precaution

    Maybe you can get some information from here: https://www.eng-tips.com/viewthread.cfm?qid=475365
  14. markboc

    Pressure at tank bottom

    What kind of pump is used? If you're not using a positive displacement pump I'd think the following: Over time the flow resistance will increase, hence your operating point moves to a greater head / lower flow rate, hence X will change. So it could be used to control the pump. Except for the...
  15. markboc

    Multiple Y-fitting to split the flow

    Just a remark: Shouldn't you avoid installing an elbow right in front of the suction side? You've give no diameters for the pipes, but at 160 m^3 / h I would guess from your model, that there's no uniform flow at the suction side. I stand to be corrected here, too. Can't help with the rest...
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