Well, yes and no. Pressure is force per unit area, but the term "area" will cancel out when dealing with a vertical column of fluid. I will humor you and say go ahead with this line of discovery. Maybe I am just jumping ahead.Pressure is force per unit area.
Still with it?
Another fan example, a shop vac, unrestricted inlet and restricted:I happen to have this squirrel cage fan in my basement.
With it operating as unrestricted as possible at full speed. 4.8 amps
With it operating with only the the inlet blocked at full speed 3.8 amps
With it operating with only the outlet blocked at full speed 3.7 amps
I have to assume you have switched the topic to positive displacement pumps and not centrifugal blowers.
During this lull in discussion (it's late at night in the UK) I would like to reiterate my point of contention here, just for clarity.Careful!
You'll have him again asserting that it relates to pumps and vertical lift.
I gave a formula for power. The basic physics is fairly simple.
Power is force times distance divided by time.
I stand behind that and I want to address it.I believe the discussion is being a little over simplified.
Yes, I am ok with this. CONTINUE!Good.
So let's look at units for pressure.
I prefer SI so let's go with that.
Force per unit area is thus Newtons per square metre.
Or the Pascal.
Still OK with that?
Gee?!?! How did I know you would pull something liike this?But you accept that pressure is force per unit area so how can you reasonably exclude area as part of that definition?
You hammered against this caveat several times last night, and I refused to budge. Now you want to pretend I never said it?Well, yes and no. Pressure is force per unit area, but the term "area" will cancel out when dealing with a vertical column of fluid. I will humor you and say go ahead with this line of discovery. Maybe I am just jumping ahead.
That being said, YES, I confirm that pressure is force per unit area.
I have never run across a centrifugal pump, or blower that does not unload when input or output is blocked regardless of the impeller type, I have worked with water pumps as well as blowers and in all cases if either is blocked the current on the motor will reduce, I have a yard blower that you can block the input or the output and while it is hard because of the volume of air it moves, it always speeds up when either is blocked (universal motor) and the blower in this case is a flat bladed half open wheel so that it can pass material, I used to call these types of pumps and blowers "slinger" in my younger days as I could never remember how to spell centrifugal, but it physics involved are the same as it uses the mass acceleration from the center of the wheel to the edge of the wheel to sling the mass outward, like the Earth would do to us if it ever started rotating faster.However, today I took a closer look at his picture and realized it was a "backward curve" impeller. These are also called "Non-overloading" impellers. They get that name because they will not overload the motor when fully blocked--regardless whether it is the inlet or outlet. They are designed such that changes in pressure differential does not change loading.
I want to thank you for the reminder, because I had completely forgotten about this until I read your posting. :thumbsup:I have never run across a centrifugal pump, or blower that does not unload when input or output is blocked regardless of the impeller type, .......