A water hammer pump is a type of hydraulic pump that does not need electrical or thermal energy for its normal operation, as it takes advantage of the kinetic energy produced by the water hammer of a fluid. A type of pump recommended for places without access to electricity and without water supply problems, with a constant source.

We will describe the technique of manufacturing a piston pump with a tube 2 inches in diameter and a flow rate of 1320 to 2700 liters per hour.

How does a ram pump work.

The operation of a hydraulic ram pump is very well explained in this video:

The operation is simple. To begin with, we need to open the valve of the pipe connected to the water source. The pressure will force the check valve to open, allowing water to enter the plastic bottle. The air inside the plastic bottle is compressed and the resistance to water ingress increases until the pressure inside the bottle increases and causes the valve to close. Since water cannot return to the supply hose, it will flow out of the tube into a tank.

It should be remembered that the ram as such wastes water, without it it could not work. They are used in places where water is constantly flowing and the inertia it brings can be used to make the water rise.


The materials needed to build our ram pump are:

  • A plastic bottle (2 liters) with a lid (A).
  • 1 x 3/4 inch reduction pad (B).
  • A PVC tee (C), with a one inch thread.
  • One PVC reducing plug (D), with 1 x 3/4 inch thread.
  • A 3/4 ” hose adapter (E).
  • 1 inch PVC nipple (F).
  • A PVC reducing plug (G), with a 2 x 1 inch thread.
  • A 2 inch (H) vertical check valve.
  • 2 galvanized nipples (I and J) of 2 inches.
  • A 2 inch galvanized tee (K).
  • A well or an impulse valve (L).
  • One 5/16 or M8 bolt with three nuts and one washer (M).
  • A toilet flush valve actuator spring (N).
  • A 2 inch diameter steel tube (O). The length varies depending on the height of the waterfall and the difference between the water to be pumped and the tank.
  • A 3/4 inch diameter steel tube (P). The length should be 10 times the pipe size of the previous element.
  • 10 cm squares of shade cloth.
  • Cable.
  • Glue for PVC.

How come.

1. Drill a 15mm diameter hole in the bottle cap (AT).

Secure the 1 x 3/4 inch reduction pad (B) with PVC glue. Then, screw the one inch tee (C) into one of its outlets, which will receive the PVC reducing pad (D). Fit this part with the pipe adapter (E) and 3/4 inch steel tube (P), in that order. At the other end of the tee, attach the one inch PVC nipple (F).

2. Screw the nipple (F) onto the 2 inch plug (G). Attach this part to the valve (H) and the 2 inch galvanized nipple (I).

3. Connect the galvanized tee (K) to the nipple. In one of its outlets, place the 2 inch steel tube (O). This supply tube must be installed 30 cm below the water level to prevent air suction and with a minimum difference of 1.5 m so that the water is channeled to the cylinder. To avoid clogging the pipe, place a piece of cloth at the entry of the cable and tie it with thread.

Four. Attach the galvanized plug to the other outlet of the tee (J) and the pulse valve shaft (L). For the cap on this valve to push water out, make a hole in the base of the strainer (supplied with the valve) to engage the 5/16 screw (M). Screw one of the nuts in the middle position of the screw. Tighten the screw until the nut touches the bottom of the strainer. Between the two nuts, tighten the washer on the free end of the screw. When repositioning the valve screen, insert the spring (N) between the washer and the valve plug.

5. To calculate the length of the steel pipe that receives the water source (O), use this formula:

Where Lq is the length of the supply pipe, H is the height at which the water moves to the reservoir and h is the height of the waterfall from the source to the ram. Assuming that S is 2.5 meters and H 15 m, we have:

6. To calculate the size of the steel pipe leading water to the tank (P), multiply the length of the supply pipe LQ by ten. Taking the example above, the value would be 168m.

A more detailed explanation of the project:

Via revistagloborural.globo.com