How Does a Hydraulic Ram Pump Work?

I made a video a while back about water hammer a hydraulic phenomenon that can lead to major problems in pipelines then I did a video on steam hammer a somewhat related phenomenon associated with steam piping systems that can be extremely dangerous and then I did a follow up to the water hammer video talking about transient vacuum phenomenon that can collapse pipes if they're not designed and operated correctly but even after those three videos it turns out I haven't told the full story because even though water hammer is generally a problem for engineers it turns out there is a way to take advantage of this normally inauspicious effect for of beneficial use i am grady and this is practical engineer on today's episode we're talking about hydraulic Grandpop's [Music] this video sponsored by Nord VPN visit Nord VPN comm / practical engineering to get 81 percent off a three-year plan more on that later a hydraulic ram is a clever device invented over 200 years ago that can pump water uphill with no other external source of power except for the water flowing into it no it's not a free energy device but if you search around you'll find lots of great implementations of this style of pump on YouTube mainly from people doing homesteading and off-grid lifestyle vlogs and it's easy to see why Ram pumps have such popularity among these groups because if you've got a piece of land with an abundant source of water a ram pump lets you get that water to a tank or a location at a higher elevation with a really elegant design that requires no electricity or fuel and only two moving parts so of course I've built my own so you can see how it works but first we need to build just a little bit of foundational knowledge on the behavior of fluids and this is something anyone can understand there are three types of energy that a fluid can have and in civil engineering we normally convert them to their equivalents as the height of a static column this distance is called the head understanding the energy in a fluid is how we solve a lot of engineering problems because in most scenarios the amount of energy stays the same and the only thing that changes is what form it takes the first type is head from gravitational potential it doesn't have an equivalent static column because it is a static column the head is just the distance from an arbitrary datum this one is easy to understand with a tank and a tube I can move this tube around wherever I want but the level in the tube and tank are always going to be the same they're both exposed to atmospheric pressure at their surface and they're not moving so there's no velocity it's just pure gravitational potential the second type of energy is pressure head in this case the head is the pressure divided by the gravity times the density of the fluid so if I close off the top of my tank and add some air pressure the level in the tube goes up the new height is the pressure head the equivalent static column related to the pressure in the tank for a given pressure a denser fluid like mercury will have a lower head compared to a lighter fluid like water because they have different unit weights a good example of measuring pressure head is a barometer we live at the bottom of an ocean of air and we like to keep track of the air pressure down here one of the easiest ways to do that is to measure how high up the pressure can push a static column of fluid in most cases mercury the final type of energy is a velocity head which relates to a fluids kinetic energy the conversion for velocity head is velocity squared divided by 2 times the gravitational acceleration I can demonstrate the equivalent column of water using a tool called a pitot tube that's a lot of background but it's important in understanding the function of a ramp-up because without an external source of power even though you can go from one type of energy to another you can't get more energy out than you had at the start for example I can convert a static column of water to one with some velocity but I'm never going to get the fluid to a higher elevation than where it started with one exception an exception that the hydraulic ram pump takes advantage of beautifully a ram pump is essentially just two one way check valves one called the waste valve and the other called the delivery valve to get it started you just momentarily open the waste valve to allow water to flow after that it's working on its own to pump the water uphill above the elevation of the source pretty amazing I think let's walk through the path of the water to understand how it works first as the waste valve opens water flows into the pump and immediately out the valve but as it picks up speed the flowing water eventually forces the waste valve to slam shut now the water is stopped in the pump it had kinetic energy but now it doesn't that means that kinetic energy was converted to something else in this case pressure this is the definition of water hammer slamming of a shut converts all the kinetic energy nearly instantly creating a huge spike in pressure that can lead to stress and damage in pipe systems and connected equipment in the case of the ram pump though that spike in pressure has a different effect it opens the second check valve and forces water entering the pump into the delivery line as you can see from my digital pressure gauge this process is cyclical pumping some of the water and wasting the rest each time the valve slams shut you can see what's happening here in real-time the pump is robbing some of the kinetic energy from the flow and imparting it to a smaller volume of water it's a redistribution of energy converting low head and high flow into high head and low flow and this type of pump can really create a lot of head I ran my discharge line up to well above the roof of my shed and my pump is still able to get the water up there sometimes an air chamber is included in the pump to smooth out those sharp spikes and pressure and provide a more even flow rate out of the delivery pipe reducing wear and tear on the pump components [Music] if you think in terms of modern electrical devices imagine we installed a hydropower turbine on a pipe to spin a generator and then use that electricity to power a pump to move the water coming out of the turbine obviously you wouldn't be able to pump all the water and anyway that would be a pretty complicated setup or something the RAM pump can do with a few very simple off-the-shelf plumbing parts in fact there is a type of pump that works from a water powered turbine maybe I'll build one of those next for now though I think the RAM pump is an ingenious way to take advantage of the properties of fluids we all need water for a variety of reasons so being able to move it where we need it without any fancy equipment or external sources of power is a pretty nice tool to have in the toolbox my privacy and online security are really important to me I don't want my 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with your browsing data that's awesome it's not true for me though and if it's not for you Nord VPN is offering an awesome discount to fans of the champ visit north VPN comm slash practical engineering or click the link in the description below to get 81 percent off a three year plan plus when you use a code practical engineering you'll get four months free and the Nord pass password manager app thank you for watching and let me know what you think [Music]

Channel: Practical Engineering

Views: 3,731,035

Rating: 4.8971081 out of 5

Keywords: ram pump, hydraulic ram, kinetic energy, steam hammer, water hammer, hydropower, hydrology, gravitational potential, fluid, pressure head, pitot tube, air pressure, Practical Engineering, Civil Engineering, Engineer, Grady

Id: zFdyqTGx32A

Length: 8min 56sec (536 seconds)

Published: Tue Dec 17 2019

Reddit Comments

[u/Dicto]

I lived on an off grid rural property for a number of years. We used a ram-pump to deliver untreated water up the side of a mountain to the homesite for use in toilets, irrigation, etc. Without the use of a power engine, the energy provided by the water traveling through a penstock down a drop in elevation of approximately 20 vertical feet provided enough energy to lift a small amount of water at a time approximately 1/4 a mile in length and almost 500 vertical feet up into a 1,500 gallon holding tank. With each cycle of the pump, only an once or two of water was delivered but over the course of 24-36 hours enough water was pumped to completely fill the storage tank.

There were a number of challenges with this system. First, the suspended turbidity in the water source quickly eroded components such as washers, valves, springs, and other components in the ram pump. At even the first sign of wear, the pump would have to be manually restarted multiple times per day. It also worked only if the penstock was completely full. If any air entered the penstock, the system would fail and all air needed to be bled out.

While it did serve its purpose, we switched over to a small solar pump with was much more reliable and efficient.

[u/[deleted]]

These things were traditionally used by English farmers to fill water troughs for sheep. You can still hear the clunking sound if you're out and about in the field in England

[u/liamliam0]

Absolutely 0 inherent interest in this subject, but I watched the whole video.

[u/sbvp]

The video explains how. Why are you asking?

Jk. Good video.

[u/heard_enough_crap]

Witchcraft! Burn him!

[u/fridgeridoo]

I still don't understand where the energy comes from

[u/ckienvan]

It was a great invention
good job

[u/Spunkie]

Is there anyway to apply a rampump to a large and deep body of water like a lake?

[u/Glen_The_Eskimo]

Grady is hiding something. Something dark. I'm on to you, Grady.