90 degrees or 45 degrees

[chiefmarvin]

I have followed Jacobs pump calculations figures in finding head pressure/lift loss. Now that my tank is drilled for herbies should I use two 090 elbwos or two 45 degree semi elbos fitting to get the water from the wier to the sump. I think the 45's would be better but I am not an engineer. I am using 1 inch bulkheads through the tank walls with 1.5 inch sanitatry tees . These tees give more of a sweep than the hard turn of a regular tee. I think they are less restrictive.

 

[Jacob D]

Re: 90 degrees or 45 degrees

<a href=showthread.php?s=&postid=14685603#post14685603 target=_blank>Originally posted</a> by chiefmarvin
I have followed Jacobs pump calculations figures in finding head pressure/lift loss.

I'm just curious... but what calc's of mine did you follow? I didn't recall having published anything regarding head loss/flow calcs, at least nothing of much use to anyone.


Regarding the elbows - there's very little, if any, advantage to using 2x 45 degree vs. 1x 90 degree. So use which ever makes it easier to plumb. Not all PVC fittings are equal, I have seen some elbows that have a sharp miter on the inside - you want to avoid these. The sanitary tee's sound good, they should provide less restriction.

 

[chiefmarvin]

I thought it was your link that showed how to calculate the gph loss by using the lift hieght from the pump to the tank and how many 90 degree elbows plumbing etc. The calc then took the pump rating in GPH and substacted for all the plumbing. Maybe it was on reef central but I thouhgt it was on your blog that you linked with your Herbie msg. Maybe I am ODing with the forums/research thing trying to get my tank set up right the first time.

 

[Jacob D]

I do have a flow calculator that I posted about on my blog, but I didn't post the actual calculator or any of the equations, data, etc...

RC has a head loss calculator, although I feel it's somewhat incomplete - and in the past I have had some strange results from it. I have a feeling that some of the pump data in there is no good (but probably most of it is ok).

 

[chiefmarvin]

I guess my basic question is .... if two 45 fittings provide less restriction and more flow than 2 90 fittings for my herbie using suction and gravity then does the same hold true for a submersible pump lifiting 54 inches in a 3/4 line. The pump is rated at 631 gph acording to the label from the mfg. ( iconverted liters to gallons) I was shooting for the ideal ten times tank volume at 750 gph but I think I can live with the 631. ( at least till I need a new pump) hence 45 or 90 degree fitting?

 

[Jacob D]

Regarding the elbows - there's very little, if any, advantage to using 2x 45 degree vs. 1x 90 degree. So use which ever makes it easier to plumb. Not all PVC fittings are equal, I have seen some elbows that have a sharp miter on the inside - you want to avoid these. The sanitary tee's sound good, they should provide less restriction.


Beyond that, you need to use the head loss calculator here on RC. If your pump is not listed I can help you figure the losses.