Hello All,
I'm working on a feasibility study for an approximately 300kW microhydro site. Design flow is about 200 l/s. For the weir, we are of course interested in flood flows. Let's assume flood flows are 2m3/s (2,000 l/s).
I'm looking for design resources or sample drawings / images...
Alternate thought / solution:
The tank is in fact just a pressure vessel (not a bladder tank). It's purpose is to simply let the water come to room temperature (therefore tempering the water somewhat at least, to about 20C). Pump is for recirculation only, so the water is not stagnant...
For the temperature issue, I would think having on-demand water heaters near the eyewash station(s) could be a good solution to this. They take a few seconds to warm up but otherwise the water would stay cold under normal conditions.
Thank you both for your continued support on this topic.
Replying to Snickster, I agree the pump should not run continuously. My suspicion is there is a problem with the bladder tank, and the system has been modified from its original purpose. Also good call on the recirc line. Perhaps it's...
Thank you all for your quick and thorough responses! I have some further investigating to do then. I agree with most of your suspicions on this.
Purpose of bladder tank - alleviate surge and provide pressurized water storage during power outage.
Purpose of pump - Boost pressure of incoming...
Hello All,
I'm trying to figure out the reasoning behind what appears to be a bizarre system installation I just inspected at a plant. It's for an emergency eyewash loop. See attached diagram I sketched for it. To me it would all make sense IF the tank was a pressure tank (bladder tank)...
Thanks Pierre, that is a good resource and actually what I started with. I find Valmatic understandably perhaps overstates the requirement for air valves (understandably because they are in the business of selling them). But it's a good resource nonetheless.
-Andrew
Final thought on this. If I am filling up this pipe for a pressure test and doing so at a relatively low velocity (say with a garden hose of 3-4 GPM) - a velocity low to evacuate trapped air at high points - how would you tackle that? I could think of:
A) simply finding a pump capable of...
Hey @LittleInch, thank you for the response. I couldn't click on the first link, does it work for you? Can you re-post it? I would be interested in seeing it.
This is another good resource I've found:
http://article.sapub.org/10.5923.j.ijhe.20180703.02.html
Like me, the authors were interested in critical velocity to remove air in small diameter pipelines.
Their experimental setup showed critical velocity as low as 0.35m/s for 5% slopes for a 1"...
That is very helpful. I completed that calculation for 2", 1.5", and 1.25" pipe sizes and corresponding increasing velocity.
It seems the velocity does indeed have a major impact on the ability to move air bubbles. At a 1.25" pipe size and flow velocity of 0.7 m/s, I almost reach the required...
Yes it's a very low angle. Change in angle less than 5%.
However, velocity is low at 0.35 m/s. I had to upsize the pipe diameter in order to avoid excessive friction loss. (I'm using an existing pump). I could change the pipe size to 1.5" which results in a velocity of 0.53 m/s.
Is there...
Thank you for the response. That makes sense. To follow up, although overall the pipeline appears to rise continuously, there are in fact a couple of high points. These are gently sloping dips over lengths of maybe 50m.
In terms of vapor lock, I am not worried about vacuum conditions...
Hello All!
I could use some feedback on the following application. I'm wondering what I need in terms of air valves for this 1km long, small diameter, low pressure pipeline. Drawing attached.
1) 2" diameter, 1km long pipeline. 2 high points where air can collect. Q = 10 GPM.
2) Same as...
Yes, something like that is what I'm looking for. I see that particular one has a steel core and HDPE gussets, presumably allowing for installation without a steel back up ring? I have since found other FF HDPE flange adapters that simply work with a steel back up ring too.
Anyways, glad to...
@XL83NL, In this case the HDPE flange adapter consists of a stub end made of HDPE, and a carbon steel backing ring. Sowhile the HDPE stub end is being "squeezed" (and actually provides the seal without a gasket, up to certain pressure), the carbon steel backing ring is the component of the RF...
