Hydraulic ram


Another principle

- Overview of what a ram and its use.

                You certainly came to an abrupt close faucet and hear a blow or shock wave in the pipe. Well, without realizing it, you just cause a water hammer. The principle is simple. By opening the tap, water picks up speed. When closing it, the water is slowed down in its course. Is the kinetic energy of water that is absorbed through the pipe, causing a shockwave. This explains the boom that we hear in the pipeline. 
  •            You have a stream or a spring that runs near your home or summer camp. It would be interesting then, to transform this flow into useful work. Like, for example, for pumping water used for watering the garden.  If it is drinkable, it would be interesting to use for water consumption. But cons, if you have two water points.Let a source of pure water that has not a big flow, and a stream with at least 30 centimeters (1 foot) vertical drop, but not drinking.It may simply serve to provide the energy needed for pumping drinking water source, separating the two by a membrane or a piston.

  • We call this assembly, compound ram.

  • - A Brief History.
    Invented in 1796 by Joseph Montgolfier, the elder brother of the famous Montgolfier balloon and his son Peter.
    The latter compound invented the ram, in which moving water is kept separate from the water to breed.

    - Principle full operation.
    See this animation of Philip FIEVET (youtube video)animation

      See Picture 3 or 4, to better understand the principle below.
        A typical hydraulic ram comprises a driving pipe, one end opens into a water tank and the other end has a valve pulse.
    The water flows into the pipe and exits through the valve pulse until it reaches a critical speed at which the valve closes suddenly and the pressure in the pipe increases.
    This increase in pressure brings some of the water line in a closed air reservoir through a check valve. Once the pressure in the drive decreases, the check valve closes and opens the valve pulse again, the cycle then repeats himself.
    The length of the pipe and driving the race valves are generally set so that there is 20 to 60 cycles per minute. The water entering the air tank, air pressure increases and displaces water in a pressure pipe, feeding a reservoir which is situated at a level higher than the supply tank.
    The hydraulic rams may be operated with very low head, not exceeding sometimes 30 cm (1 ft) and can raise water to heights exceeding 120 m (400 ft). They operate without fuel or lubricants or external source of power, and require only very low maintenance check before wear. The lifetime of the latter is 10 to 30 years, and some hydraulic rams, in which we made only replacement, ran for over 100 years. Unfortunately, the motive water flow must be very large compared with the high volume of water. The relationship between these two values is usually 1.5 to 2 times the ratio of the height elevation and height drive. Rams were used compounds for raising water sources that do not provide enough water driving, using energy from a nearby stream, whose water is introduced into the driving pipe. The increased pressure is used to raise a balanced piston spring which makes the pumping of water from the source. The large quantities of water necessary driving, limit the use of hydraulic rams, and they are normally used to supply water to farms and isolated hamlets. Some facilities have provided up to 545,000 liters (120,000 gallons) per day. Other applications of hydraulic rams would be possible, as, for example, use rams air compressors or hydraulic rams use lead compounds for heat pumps.

    - My ram staff, and how to build it.
        It's been about 15 years that I have a hydraulic ram, for watering the garden during the summer. And it gives me satisfaction. I have changed any parts on it since that time. In addition, failing to find a ram manufactured very rare in these modern times, or electric pumps to take advantage of any other system. I've made a plastic. Easy to build, and very inexpensive. Here are two diagrams, Picture 1, assembly of plastic plumbing, and Picture 2, assembly or galvanized metal plumbing. The whole is mounted on pipe and valve 1 inch.

    -Now the explanation in detail of the pulse valve.
    Step 1
        Get a brass valve, normally used in wells to prevent the return of the water.
    And remove the strainer, because we do not need to mount that interests us.
    Step 2
        Remove the valve and spring from the valve body. These two items, suffer the same fate as the strainer. That is to say, they are useless for this circuit.
    Step 3
         Obtain two bolts, one of a length of about 6 millimeters by 75 millimeters (1 / 4 "x 3") with net to end only. Or length proportional to the valve.
    Put simply, the bolt head should be supported on the end of the valve body, where was set the strainer. Nets must be at the valve. This gives you the true measure that should have your bolt. Note that it must surely pierce the old screw hole of the screen, slightly larger than your bolt, to prevent friction damage the operation of the pulse valve.
    And another bolt of same size by 40 millimeters (1 1 / 2 ") long. It will be used to support the weight, which varies depending on the flow and the shock wave (explanation on the weight given more below in the section, (how much to operate a hydraulic ram).
    Weld bolts head to head, as shown.

        Now the assembly of the valve.
    Rub the longer bolts, the upper body of the valve.Place a first nut on the bolt, followed by a washer which must necessarily be smaller than the hole in the seat of the valve. Cut a rubber washer in a tire inner tube, and make him a perforation in its center to fasten the bolt. Its diameter should cover the valve seat in full but without excess, it must not touch the outer wall. By cons, if the original valve washer may be recovered, use it. Except in cases where it can be placed between two metal washers, without any distortion. Very important because it is in the tightness of the pulse valve.
    The lower metal washer will be used to support the rubber washer, and its circumference is substantially the same as that of rubber without excess, it should not hit the outer walls.
    Step 4
        Leave support the bolt head on the base of the valve. It'll just adjust the opening thereof, by tightening the nuts to bring the rubber washer at about 5-8 millimeters of the seat. Finally, tighten the nuts without exaggeration, we must not distort the rubber washer.

        As you probably know, the liquids are incompressible. That is why we need an air tank. The elasticity of the air serves to stabilize the water hammer effect. So it stores the kinetic energy of water by volume reduction and pressure increase. A tank with a capacity of 8 liters (2 gallons) is enough. But it is often very difficult to find too small. Despite their small size, they are often expensive. Here is how I remedied the situation.
    Picture 4 shows a tank made of ABS glue.

        Here is the configuration of the site or my ram is installed. Do not forget to add a strainer at the source of the supply pipe to prevent clogging of valves, or by debris accumulated deposits.


        You have completed the installation of the ram as in picture 1 or 2 including tank, valve impulse and restraint. Now comes the installation of the system as a whole. That is to say, setting the ram to keep it perfectly vertical, throughout the duration of its operation. Then connect the supply line, a board on it. Take a quality plastic pipes above, it should be a greater thickness than a regular pipe, which works but still lost some kinetic energy due to its thinness and elasticity. Metal pipes are the best of the range for the conservation of the kinetic energy of water hammer. It can go for short distances, but it remains expensive and its life is shorter, you guessed it, because it corrodes. Add a strainer at its end, this prevents impurities from entering the system. It only remains to fix the discharge pipe, who brings water pumping to storage tank. This duct may be of a size less than supply line, this does not affect on the performance of the pump is a fundamental law (fundamental formula of hydrostatics), whatever the volume pressure remains the same at a given level.
        The pressure remains the same at the tank level control of the ram. Except for exceedingly small pipe in this situation it may only produce resistance and decrease system performance. In other words, this may explain a gibberish. More you'll have to send in your height and pumping more you can reduce the size of this pipe. Because the higher you go the less one has water pumping due to a surplus of energy required for mounted. Its small size is only a matter of economics.

    -How to successfully operate a hydraulic ram
        Well finally here we are. The long awaited moment of all. The start of its new hydraulic ram. First adjustment, the valve opening pulse. In Picture 3, step 4, there is mention of an opening of 5 to 8 mm. Well, 5 mm is a minimum and it is associated with a waterfall of only 30 centimeters. There are too many factors to consider for just a measure or calculation table to obtain an accurate measure of openness in millimeters. I'll still give you something to help you succeed in this adjustment. If you `re not in the situation least a waterfall only 30 centimeters high, then 8 mm is a good start for future adjustments. If the supply line (driving pipe) is tortuous and must make a few waves, this is a factor influencing the shock wave (water hammer). And the number of hammer minute is directly related to the length of the supply pipe, with the exception of its sinuosity and absorption of kinetic energy by the latter (quality and robustness of the duct). For these reasons I make mention of the inability to give accurate measurements, there are too many factors to consider. But I still give you some empirical measures. Driving pipe with a minimum length of 15 meters (about 50 feet) requires 60 shots to the minute pulse valve. Driving pipe with a maximum length of 155 meters (500 feet) requires 10 strokes to the minute pulse valve. Exceeded this length, an echo of the primary shock wave felt, and the hammering out of sync, it disrupts the system enough to cause it to stop after a certain period. We can perceive in listening to the check valve work, just to put your ear against the reservoir regulation. When the pulse valve closes suddenly, one perceives the primary shock wave through the vibration of the check valve at the moment it seems to decrease in intensity of a second wave that is felt shorter and ends with the reopening of the pulse valve. This is valid for long pipes, the phenomenon decreases as the length of the duct. In 15 years I had time to experiment a lot about it. So much for starting the adjustment. Taking the next step now.

    -Booting the system.
        Take the pulse valve open until there is no more air into the driving pipe. Water must flow regularly and not jerk. Then release the pulse valve, it will slam shut (if it does not close by itself is that its opening is too large, cut a few millimeters). Repeat this gesture of opening and closing of the pulse valve, until water comes out the discharge pipe, to your storage tank. This is intended to fill and stabilize the pressure required for your system. From that moment, the pulse valve should function without it having to intervene in its opening movement and closing. It is possible that after a few strokes she stopped. In this case, add weight by placing a metal washer to the upper end of the bolt. Take care to complete with the nut tight, because these washers should not interfere with the valve bouncing. A ram is like a clockwork system. Must be synchronized with the shock wave, which may vary slightly from one system to another, depending on the layout of site etc ... We arrived at a critical stage of assembly. Adjust the number of rounds per minute of the pulse valve. The best advice I can provide you at this stage it. Is to add weight by placing a metal washer every time and restarting the pulse valve, until it remains open by excess weight. You of course remove the last puck is too much. So this will give you the maximum kinetic energy recovered through the valve. The question that follows is. Do we have the right number of strokes per minute? So be patient and lap top. There are two possibilities, he beats a few rounds in less than a minute. I told you that this is no big deal. Because from experience, the more you cheat by lowering the number of pulses, a larger valve opening and a decrease in weight, it becomes more and more pressure regulation reservoir. It needs a higher pressure when the storage tank is placed above, it will later determine how many minutes it takes to pump a liter in the tank, just to know how many liters per 24 hour are pumped through the system. But if the moves are too fast, it may eventually stop by itself, by a desynchronization of the shock wave. To decrease its speed slightly increasing valve opening pulse, and start over with the weight. For the weight this is still the same principle. In any case, it must exceed the weight necessary, until the pulse valve can be closed by itself, and then remove the excess, until it be able to get these shots regularly. This is aimed at the risk of repeating myself, to recover the maximum kinetic energy available for driving pipe. I am confident that you will contact me due to the adjustment thereof. But I'd like to hear from you too, when everything works for the better. This gives me the satisfaction of not having created this document in vain.
    -Example and table-calculation

    I'll give you a very brief explanation of ram 1 inch and 2 inchs thick. For a good percentage yield pumping, stay in a minimum ratio of 6 times the height of drop for the length of the driving pipe of the metallic type. The delivery height minimum is 1 / 3 higher than the fall or driving pipe, or the ratio of 3 is a better ratio of 8. Exemple : 1 inch ram, suction height of 40 meters for a driving pipe with a fall or drop of 5 meters and a metal pipe for this driving pipe 30 meters in length. Now how much water the ram in theory, will provide for pumping. Amount of water absorbed by the driving pipe in liters per minute.
    Type of ram Ratio (line length) / (head)

    6 7 8
    1 inch 6,6 6,1 5,6
    2 inches 12,9 12,2 11,5

    Then the percentage or yield for a ram pump and driving pipe metal.

    Type of ram Report (delivery head) / (head)

    4 6 8 10 12
    1 inch
    50% 54% 54% 48% 40%
    2 inches 52% 56% 56% 50% 44%

    Returning to the example of a 1-inch ram. The amount of water flowing through the driving pipe was 6.6 liters / minute. Taking into account the percentage of return of the ram, by about 54%. which gives us hope of a pumping 3.5 liters per minute at the discharge outlet to 40 feet above. Hope this can help you better!
        For more information, or just for fun to discuss, contact me
        At this point, everything should work fine, and your storage tank to start filling up. And I suspect even a smile on your face undisguised, while contemplating your system. Quite amazed by its operating principle that you know now. Imagine when passersby, friends and family ask how it works there? You will be pleased to explain, just as I have just done.
    So I only wish you good luck in your collage.
    And have fun!

    video bélier 01Video 1 ram running.
    video 2 bélien en marcheVideo 2 ram running

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