

14102015, 02:05

#136

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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by sailorchic34
sure
Volume is a displacement measurement, such as gallons, where one gallon displaces a volume of .1336 cubic feet, give or take
Volume flow rate: is a measure of the volume of fluid passing a point in the system per unit time
..........
So GPH for example is volume of fluid passing a point in the system per unit of time. where gallons is simply a volume

Thanks, that makes sense to me
Would it be correct then to say one of these terms (gallons) tells me how much diesel I might have say in my fuel tank and the other (GPH) tells me how fast that diesel is going into the engine?
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All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence



14102015, 02:16

#137

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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by sailorchic34
I would love it, yet the defination of a GPH is a measure of the volume of fluid passing a point in the system per unit time.

Please stop wiggling and just give a simple answer of Yes or No to the question:
"Can we now agree that GPH is not a volume? "
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14102015, 03:00

#138

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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by StuM
Please stop wiggling and just give a simple answer of Yes or No to the question:
"Can we now agree that GPH is not a volume? "

No one is arguing that GPH is a volume except you. For the 100th time GPH is a volumetric rate.
1 GPH is 231 inches cubed per hour flowing past a point. If we let the fluid trickle into a pail then in one hour there will be 1 gallon or 231 inches cubed of water in the pail.



14102015, 03:57

#139

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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by LakeSuperior
No one is arguing that GPH is a volume except you. For the 100th time GPH is a volumetric rate.
1 GPH is 231 inches cubed per hour flowing past a point. If we let the fluid trickle into a pail then in one hour there will be 1 gallon or 231 inches cubed of water in the pail.

I suggest going back and looking at sailor chicks posts on this thread and the parent thread about refridgeration.
She is emphatic that GPH is a measure of volume.
quotes:
 0.1gph/day would be the same as saying 2.4 GPD (Gallons per day).
 But I have used GPM and GPH to size water and fuel tanks
On the fridge thread, she was insistent that her jerrycan holds between 0 and 4.45 gph.
She does not seem to grasp that there is a difference between a flow rate combined with a duration can be used to claculate a volume but without the duration, a flow rate is not a volume. If you read her responses, she keeps mixing up the subject by assuming a duration.



14102015, 04:13

#140

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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by LakeSuperior
No one is arguing that GPH is a volume except you. For the 100th time GPH is a volumetric rate.

You have obviously misunderstood almost the entire thread.
No on is arguing that GPH is a volume except SC.
Go back and read her posts.



14102015, 04:41

#141

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Join Date: Apr 2012
Posts: 577

Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by sailorchic34
If you know GPH you can calculate tank volume...

George pulls his Dodge RAM into the gas station and fills his gas tank. The positive displacement pump fills his tank at 2.0 GPM. How big is his fuel tank?
Mandy pulls into the same station in her KIA Soul soon after George, and uses the same pump. She fills her tank. How big is her fuel tank?
You don't know either tank volume unless you know how long it takes to fill them. So,
Volume/time x time = Volume, which should make it clear that Volume/time does not equal volume, but the rate of change of volume...which could be a flow rate,
Or it could be the rate of change of an expanding or contracting volume.
For example, if I blow up a balloon with a gas flow rate of 1.0 standard cubic foot per minute, and the balloon expands to accommodate that rate, the volume is changing according to dV/dt=Rd(nT/P)/dt. To know the volume of the balloon (the container for this case), you would need to know the temperature and the pressure and the mass of gas in the balloon (which requires more knowledge than the volumetric flow rate).
So you can calculate volume if you know other things, but volumetric flow rate is not volume.
To say so is kind of like saying if I know the length of a tank then I know its volume. You can calculate it, if you know the shape and other dimensions, but length is not volume.



14102015, 07:37

#142

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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by fryewe
George pulls his Dodge RAM into the gas station and fills his gas tank. The positive displacement pump fills his tank at 2.0 GPM. How big is his fuel tank?
Mandy pulls into the same station in her KIA Soul soon after George, and uses the same pump. She fills her tank. How big is her fuel tank?
You don't know either tank volume unless you know how long it takes to fill them. So,
Volume/time x time = Volume, which should make it clear that Volume/time does not equal volume, but the rate of change of volume...which could be a flow rate,
Or it could be the rate of change of an expanding or contracting volume.
For example, if I blow up a balloon with a gas flow rate of 1.0 standard cubic foot per minute, and the balloon expands to accommodate that rate, the volume is changing according to dV/dt=Rd(nT/P)/dt. To know the volume of the balloon (the container for this case), you would need to know the temperature and the pressure and the mass of gas in the balloon (which requires more knowledge than the volumetric flow rate).
So you can calculate volume if you know other things, but volumetric flow rate is not volume.
To say so is kind of like saying if I know the length of a tank then I know its volume. You can calculate it, if you know the shape and other dimensions, but length is not volume.

Ah, Sorry, I guess I was not clear, If I have to size a tank to hold a volume and its being filled at 600 gph. I know that if I want to hold an hours worth of fuel it would need to be at least 600 gallons. Thats what I've done in the past.
So lets change units for a bit. Lets use Feet per second (FPS) and Cubic feet per second (CFPS). The first FPS is simply a rate of speed. The second is volume flowing per second. So 10 CFPS would fill a volune of 10 cubic feet in one second/ Just as a flow rate of 10 GPH will fill a volume of 10 gallons in one hour. It is a Volumetric rate
Your statement Volume/time x time = Volume, is not quite correct. GPH is gallons per hour, Not gallons per hour per hour It already has a time unit of one hour implied. If you say GPH/HR that is a rate change.



14102015, 07:48

#143

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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by sailorchic34
Ah, Sorry, I guess I was not clear
Your statement Volume/time x time = Volume, is not quite correct. GPH is gallons per hour, Not gallons per hour per hour It already has a time unit of one hour implied. If you say GPH/HR that is a rate change.

Yes, agree with the first sentense..
Volume/time x time = volume, is correct. He didn't say it was GPH..
GPH/Hr is a rate of rate change..
BR Teddy



14102015, 07:52

#144

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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by Wotname
Thanks, that makes sense to me
Would it be correct then to say one of these terms (gallons) tells me how much diesel I might have say in my fuel tank and the other (GPH) tells me how fast that diesel is going into the engine?

Hum, If your engine uses 1 GPH of diesel per hour, is that a unit of speed or of volume. A unit of 1 GPH does not imply speed or how fast it's flowing. The speed of flow would be the product of velocity. That would be Feet per second or meters per second. So if your moving a GPH in a 1/4" diameter pipe it has one speed of flow (how fast it travels). In 1" pipe that speed of flow would be much slower, but the flow rate of 1 gph would be the same. So in my mind GPH is not a speed of flow but a volume of flow per time period.
I hope that is somewhat clear.



14102015, 07:53

#145

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Join Date: Apr 2012
Posts: 577

Re: Amps v Amp hours v Amps/Hr
Quote:
Your statement Volume/time x time = Volume, is not quite correct.

I'm done.
Somewhere around here there has to be an emoji with a light bulb over the smiley face...now where did I put that?



14102015, 07:58

#146

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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by TeddyDiver
Yes, agree with the first sentense..
Volume/time x time = volume, is correct. He didn't say it was GPH..
GPH/Hr is a rate of rate change..
BR Teddy

AH yes, your right. Volume per unit time is the definition of GPH. But in engineering we use GPH without an additional time unit (GPHX time as GPH in itself implies a flow volume per time.



14102015, 08:03

#147

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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by sailorchic34
So lets change units for a bit. Lets use Feet per second (FPS) and Cubic feet per second (CFPS). The first FPS is simply a rate of speed. The second is volume flowing per second. So 10 CFPS would fill a volune of 10 cubic feet in one second/ Just as a flow rate of 10 GPH will fill a volume of 10 gallons in one hour. It is a Volumetric rate
Your statement Volume/time x time = Volume, is not quite correct. GPH is gallons per hour, Not gallons per hour per hour It already has a time unit of one hour implied. If you say GPH/HR that is a rate change.

Okay, I'll try one more time.
Let's use feet per sec (FPS). You say FPS is a rate of speed. It is not. It is speed. A rate of change of speed is acceleration. FPS is rate of motion...feet/second. If you know the speed, in FPS, and the duration of the motion, you can calculate the distance traveled.
Let's use cubic feet per second (CFPS). This is the volume of flow per second as you say. And a flow of 10 CFPS would fill a 10 CFPS tank in one second, and a flow rate of 10 GPH would fill a 10 GPH tank in one hour. It is a volumetric flow rate...not a volume...and to take your example and expanding the acronym...
10 Ft3/sec x 1 sec = 10 Ft3, and that is Volume/time x time.
and
10 Gal/hour x 1 hour = 10 Gal, and that is Volume/time x time.
GPH/Hr is a rate change...and GPH is a rate...and G is a volume.
Now I'm done...I think.



14102015, 08:14

#148

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Join Date: Apr 2013
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by sailorchic34
Ah, Sorry, I guess I was not clear, If I have to size a tank to hold a volume and its being filled at 600 gph. I know that if I want to hold an hours worth of fuel it would need to be at least 600 gallons. Thats what I've done in the past. This disagrees with your prior posts where you said GPH is a volume and we challenged you to tell us the volume without adding more information (such as how long the flow rate lasts)
So lets change units for a bit. Lets use Feet per second (FPS) and Cubic feet per second (CFPS). The first FPS is simply a rate of speed. The second is volume flowing per second. So 10 CFPS would fill a volune of 10 cubic feet in one second/ Just as a flow rate of 10 GPH will fill a volume of 10 gallons in one hour. It is a Volumetric rate But before you were saying it was a volume...hmmm...
Your statement Volume/time x time = Volume, is not quite correct. GPH is gallons per hour, Not gallons per hour per hour It already has a time unit of one hour implied. If you say GPH/HR that is a rate change. Only if you purposely misread the formula. It would have been better to use () but there are no spaces around the "/" but there are spaces around the "x". That means it is equivilent to (volume/time) x time

How are those 04.45ish GPH jugs working out for you?



14102015, 08:22

#149

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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by fryewe
Okay, I'll try one more time.
10 Ft3/sec x 1 sec = 10 Ft3, and that is Volume/time x time.

Agree with almost everything you say.
10 CFS x 1 sec is the same as saying 10 CFS both are a volume of 10CF per unit time.



14102015, 08:30

#150

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Join Date: Apr 2012
Posts: 577

Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by sailorchic34
Agree with almost everything you say.
10 CFS x 1 sec is the same as saying 10 CFS both are a volume of 10CF per unit time.

No. I didn't say that, and neither should you.
10 CFPS x 1 sec is the same as saying 10 CF...not CFS. 10 CFS is not the same.
10 CF per unit of time is a volume per unit of time, not a volume.
I still gotta think you are bored, and keeping this thread going by pulling our legs.
I find it hard to believe that you understand motor theory well enough to point out that current draw can increase with a drop in terminal voltage on a dc motor, but have trouble with the most basic unit analysis problem that you should have learned in eighth grade science, reviewed in high school physics, and used in every science and engineering course you would have taken in college.
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