J_J
Super Star Member
- Joined
- Sep 6, 2003
- Messages
- 18,952
- Location
- JACKSONVILLE, FL
- Tractor
- Power-Trac 1445, KUBOTA B-9200HST
Punp volume will try and remain the same at a set rpm.
Yes, except you are not able to decrease the output of a steady speed positive displacement pump. The restricted line causes V and P to increase in order to forcethe fixed output of our "perfect" pump thru that restriction. The fact that something will finally fail with greater and greater restriction is not part of the thot problem with the given boundary conditions [which are defined to exclude heat and pump and fluid imperfectness]. The amount of pressure rise with restriction is good to have a mental handle on tho so you can sorta "feel" the circuit in your head.Something is still not right here. If you start decreasing the output of the hose/line, with smaller orifice, the pressure will increase, and the velocity through the orifice will increase. The smaller the orifice, more pressure is developed, until you close it off completely, and the pump develops burst pressure. Is this correct?
You Nailed it J_J!!:thumbsup:Something is still not right here. With a constant rpm, on a gear type pump, the volume through a tube will be the GPM's for the pump, with no or little pressure. If you start decreasing the output of the hose/line, with smaller orifice, the pressure will increase, and the velocity through the orifice will increase. The smaller the orifice, more pressure is developed, until you close it off completely, and the pump develops burst pressure. Is this correct?
Yes.
Also in a closed loop system as the aperture gets smaller the fluid may heat up, change characteristics, and result in a loss of NPSH to the point no fluid is being pumped.:thumbsup:
A normal system will not get any substantial changes in fluid characteristics from "normal over heating"....so lets leave that part of the discussion out. It only confuses more than helps to understand the basics of this
sorry to hear that your part of the "big world" have so rough conditions....LOLIt does happen out there in the big wide world.:thumbsup:
So thats how you got your 13000+ posts....talking about stuff you don't know anything about.....NPSH- well I don't really know what that means.
head pressure might become a factor when fluid is closer to solid (frozen) or gas (boiling), than liquid....:thumbsup:Seen it somewhere though and thought it sounds good. Maybe it reminds me of the odd -35C evening and a 8 in. intake and a buried tank!!:laughing:
sorry to hear that your part of the "big world" have so rough conditions....LOL
head pressure might become a factor when fluid is closer to solid (frozen) or gas (boiling), than liquid....:thumbsup: