Pump Bypass

Collecting, filtering and dewatering of WVO SVO vegetable oil. For Biodiesel producers too.

Moderators: SunWizard, coachgeo

Pump Bypass

Postby tubular031 » Mon Nov 09, 2009 10:45 am

I have been asking lots of questions about pumps lately!

I am changing my setup in the garage. I will have a tote as my catch barrel for clean oil coming out of my gravity CF. Now that I will have lots of oil, I plan on filling my tank up rather then putting 15 gal at a time in it like my old setup would yield. I use a blue HF water pump to suck the oil from my tank through 2 filters and into the truck. I want to make some kind of bypass so I can fill the truck up and when its full, let go of the trigger on the nozzle and then walk over to the pump and shut it off. I have been eyeballing that diesel transfer pump on northerntool that has the internal bypass or the one from redline with the internal bypass but don't want to spend the $250+ on them.

On my HF pump that pumps water I put a T on the input and a T on the output with a ball valve in between. This would allow me to adjust the pressure in the line. I used this pump to run some sprinklers off a rain catch setup. Worked sweet.
01 F350 CCLB SRW

Veggie conversion done!
http://www.burnveg.com/forum/viewtopic.php?t=623
tubular031
 
Posts: 83
Joined: Tue Apr 29, 2008 2:47 pm

Postby David » Mon Nov 09, 2009 10:40 pm

I'm not sure why you even need a bypass in the first place?
The HF pumps are centrifugal so closing off the flow is not going to hurt them contrary to popular misinformation. There was a discussion about this on the local forum a while back and the next day an electritian friend came over and we were discussing it. He got out his clamp meter and we measured the current draw on 2 different centrifugal pumps I had and both used less current when the flow was shut off than when the oil was actually flowing.

If your nozzle is remotely decent, it will have no trouble holding back the feeble pressure one of those pumps generates.
If you are the pedantic kind and have to have some sort of additional setup on your pump to be able to sleep at night, I would suggest another less complicated approach.

I had a trigger nozzle on my SBC collection pump and lbeing a gear pump, it was not possible just to shut the flow off with the nozzle. The pump itself had to be stopped first.
I fitted a car door pin type switch to the trigger handle so it would not turn the pump on till the trigger was nearly all the way pulled back and it would cut off as soon as the handle was released again.

All you would need to do would be put the same sort of setup on your nozzle and run it back to a relay which turned your pump on and off. Use a 12/ 240 type relay so you can have all the high voltage in a box where it is safe and the only voltage in the switch itself is harmless.

Another way may be an adjustable pressure switch on the output so when you drop the trigger on the nozzle the pressure builds for a second and having reached it's preset, turns the pump off. You may need a one way valve in the line or the pump may want to cycle as the pressure builds than drops off as it leaks past the impeller in the pump and drops again.

Again, there is no need to bypass the flow or turn the pump off if you close the flow with the trigger but a switch would be a better way of approaching what you want to do than a bypass.
_____________________

I don't give a damn about what might or could happen until a significant group of people can tell me it HAS happened to them.
Until then, it's just more endless gloom and doom Veg folk law.
David
 
Posts: 333
Joined: Thu Mar 06, 2008 4:12 am
Location: Sydney Australia

Postby tubular031 » Tue Nov 10, 2009 8:19 am

I was thinking about this last night and came up with the same answers you did! I think ill try the switch/relay method. I have access to limit switches and relays at work.

I was looking on mcmaster at pressure relief valves and they are pretty expensive.

Thanks for your input
01 F350 CCLB SRW

Veggie conversion done!
http://www.burnveg.com/forum/viewtopic.php?t=623
tubular031
 
Posts: 83
Joined: Tue Apr 29, 2008 2:47 pm


Return to Vegetable oil Collecting, Filtering and Dewatering

Who is online

Users browsing this forum: No registered users and 0 guests

cron