Pump Head: Simple Explanation

[Music] hi Krista thirsty worst here today we're going to be talking about pump head and I'm going to offer a simple explanation that overviews what pump head is essentially so head is a measurement of the amount of pressure required to successfully deliver the fluid pumped at the desired flow now the key parts to remember here is the amount of pressure required to successfully deliver the fluid pumped at the desired flow so the amount of pressure of course would be whatever pressure is needed so for a home you may need somewhere between 40 to 60 psi as a target number at home if you're filling a reservoir you're not going to really need any pressure at all you're just looking to get the water in the tank and in most sewage applications where solids handling is involved there's not necessarily a requirement for pressure in most cases and but in a lot of like effluent sewers and on-site sewer systems where you may have like a pressurized drain field you're certainly going to be looking at some requirements that involve pressure so not to over complicate things the pressure is pressure so the desired flow of course is the amount of fluid that you need delivered how many gallons per minute is typically the question that I'm going to ask when when I'm trying to find out what a person needs in terms of flow so really there's there's going to be only two basic factors in dealing with pump head in its most basic form so you've got lift and you've got loss so let's talk about lift lift as it boils down is essentially the elevation difference from point A to point B here from from where the pump is located to where the fluid needs to be pumped to so that's typically the elevation difference now it has no bearing on the distance between point a and point B but only the vertical difference so one foot vertically would be one foot of head regardless of if the pump is a hundred foot away from the discharge location a one foot rise is a one foot rise so it's important to realize that when calculating a list or the elevation you're only taking into account the height differential between where the pump sits and where the discharge location is going to be we'll talk a minute about flow and pressure so these are basically the other two components that tie into that that second factor so when you're talking about flow the pressure of course flow being the amount of fluid that you need delivered at a particular location and in a lot of sewer applications you're going to be basing your flow on the amount of inflow so how much waste is going into the tank or basin and then sizing the pump typically based on how much is expected to need to be pumped so in a well pump application for delivering water to a home you may only be basing it on how much water the house is going to use plus any any irrigation or anything on top of that pressure I think that we nailed that down pretty tight in a couple earlier slides so once we know our flow then we're able to determine our friction loss so when it comes to friction loss this is going to be the second factor that's going to contribute to your total head or total dynamic head in a lot of cases so when talking about friction loss what we're referring to is the amount of energy that's absorbed as the fluid is transported through the piping and the plumbing in the fittings and so forth so as the liquid travels through the pipe it drags on the walls of the pipe and drags on the fitting and that creates resistance and that resistance we need to compensate for in order to properly deliver the fluid at the desired flow and pressure so we're talking about friction loss we're going to look at what is the total linear length of pipe it's so if you've got a hundred feet of pipe that's 100 feet of pipe regardless of any elevation changes that is factored in completely separately from your friction loss characteristic you're going to want to make sure you tally up any pipe lengths you're going to want to know what material the pipe is and you're going to want to count up all of your fittings and then you're going to refer to a friction loss worksheet which there's plenty of friction loss calculations available on the internet I'm going to put a couple of friction loss calculators in the description below for you to easily use in reference and once you've determined your friction loss friction loss or head losses it's commonly referred to the unit that it's represented in is feet in most cases so you may have five feet of friction loss 10 feet of friction loss 20 feet of friction loss whatever the calculation you know comes up with and then you'll have to then add that to your other calculation so in order to get your total head at a specific flow of course because we're basing the friction loss on the flow through the pipe and as the flow increases the friction factor increases so when you're doing this calculation it's only based on the specific flow that you've targeted we just simply take our elevation we add our pressure and our friction loss and the thing to remember here of course is elevation is already going to be in feet in most cases it's not converted to feet your pressure needs to be converted to feet and in order to convert pressure to feet 1 psi equals 2.31 head feet you just take whatever your desired pressure is multiply that by 2.31 and then you're going to have that number now converted to feet so you take your elevation add add your pressure in feet add your friction loss in feet and you're going to have the total feet head that you're going to need for that specific location in terms of calculating head this is really all that you're going to need to know for a basic conceptual understanding now of course there's a little bit more depth involved when when accounting for specialized systems but for your basic day-to-day head calculations these are going to be the main factors that are going to contribute the most information and allow you to properly select a pump in almost 99% of cases for like a residential scale application where you're not dealing with excessive distances and excessive elevation or excessive amounts of plumbing what we want to do here is we're going to work on putting together some additional videos on reading a pump curve understanding suction heads and kind of walk us through the steps here so stay tuned make sure to LIKE and subscribe for more videos like this we really appreciate you watching if you have any questions leave those in the comments below we'd love to hear from you and get back to you so thanks for watching have a great day [Music]

Channel: R.C. Worst & Co., Inc.

Views: 290,596

Keywords: Pump, PUmp head, sizing a pump, pump sizing, Flow, pressure, loss, pump curve, curve, friction loss, friction, RC worst, rcworst, rcworst youtube, Water pumps equipment, water pumps, pump, pumps, pump head, pump head calculation, how to calculate pump head, what is pump head, npsh, pump head curve, pump head calculation in hvac, pump head calculation for chilled water system, pump head calculation formula, how to calculate pump head from flow rate, how to calculate pump head required

Id: mtP-9arHJuM

Length: 7min 20sec (440 seconds)

Published: Mon Mar 06 2017