THE WAVE-POWERED PUMP AND SOME IMPORTANT APPLICATIONS
On reading a book called Waves and Beaches by Willard Bascom (Anchor Books, 1980), I found a description of what I thought was a very clever device. It was a wave powered pump invented by John Isaacs, a simple and versatile device. Since that time I have often thought about applications for it. The pump consists of a float connected to a long pipe that hangs below it in the water. The pipe is fitted with a check valve that permits water to flow in only one direction. As the float and pipe move up and down with the waves, the water column in the pipe is forced to move along with the pipe but only when the pipe is moving in the direction that forces the valve in the pipe to close and then, due to the momentum of the moving water, it continues to move in that direction even when the motion of the pipe reverses and the valve opens. This action results in a continuous flow of water through the pipe. The volume of water pumped through the pipe is proportional to the cross sectional area of the inside of the pipe and to the maximum speed of the up-down motion of the pipe. For a given size float, it can pump a lot of water at low pressure or a little water at high pressure. A short fat pipe will pump a lot of water at low pressure and a long thin pipe will pump less water, but at high pressure. The pressure due to the flow of the water in the pipe is proportional to the length of the pipe. For construction details see below.
Here are some proposed applications:
Ocean Fertility Augmentation
In most areas of the tropical oceans the warm surface water is depleted of nutrients and therefore mostly devoid of life. However, the cold deep water below has lots of nutrients. In fact, the most fertile regions of the oceans are the areas where the cold deep water mixes with the surface water such as off the coast of Peru and in the polar regions
In places where the cold water is close enough to the surface to reach with a wave powered pump the deep water can be mixed with the surface water and the fertility of the ocean can be increased in that area thus providing a productive fishery where there was none before.
Where warm surface water and cold subsurface water are both available near land there are additional possibilities. For example, the temperature differential between the cold water and the warm surface water can be used to generate power (Ocean Thermal Energy Conversion). Or the cold water can be piped to land and used for air conditioning and then the water can be piped to large ponds where the dissolved nutrients and sunlight support the growth of algae and other marine life that can be harvested for food.
Hurricane Control
Hurricanes extract energy from warm surface waters on the ocean. If this warm water could be mixed with cooler water from below then the intensity of hurricanes in that region would be reduced. This is a job that the pumps can do.
The pumps will drift with the ocean currents and will have to be retrieved by ships before they reach shallow water and are destroyed. They can be then transported and redeployed. Locating the pumps can be made easy by mounting a radar reflector or even a radio beacon on them. Periodically removing the pumps from the water also eliminates the problem of bio-fouling as seaweed and barnacles can not tolerate the prolonged drying caused by transport on the deck of a ship. The pumps can be modified to remain in the desired area for a longer time if there is a predictable relationship between the direction of the ocean currents and the prevailing wind direction. The pumps can then move themselves in any desired direction. This would be accomplished by placing a wind tail on one side of the float so that the float always points upwind. The water discharge can then be directed horizontally to propel the pump in the desired direction relative to the wind. The pumps can even be made steerable by remote control if the orientation of the wind vane can be servo controlled by radio. It is not necessary for every pump to be controlled in this way as many pumps can be tethered together and steered by one.
Of course, since the pump takes its energy from the waves, it reduces the intensity of the waves. This may reduce shoreline damage during a storm. Using these pumps to control hurricanes would require a lot of pumps covering a large area. However, when compared to the cost of the devastation caused by hurricanes, the pumps will be cheap. They need only be deployed in the path of a large hurricane heading for a populated area and can be stored on land between uses.
Elimination of the “Dead Zone” in the Gulf of Mexico
The Gulf of Mexico has a very large region called the “Dead Zone” in which the subsurface life has been killed off by lack of oxygen. This is a result of fertilizer runoff from farm fields carried to the gulf by the Mississippi River. The fresh water from the river contains fertilizer and it flows out into the gulf over the denser salt water. The fertilizer causes a bloom of algae that eventually sinks below the surface and decomposes. This decomposition uses up all of the available oxygen in the deep water and so the animal life there is killed. There is very little mixing of the surface water with the de-oxygenated water below because the surface water is lighter than the deep salty water below.
The dead zone could be eliminated if the surface water, which has plenty of oxygen, could be mixed with the water below. The wave powered pump could do this.
The best way to do the mixing is to pump salty water from below and mix it with the surface water. This will permit the growth of the algae while making the surface water salty and reducing the density difference of the surface water with the deep salty water below. Reducing the density difference between the surface water and the deep water will permit the oxygenated surface water to mix naturally with the deeper water and restore the oxygen to the deep water.
The alternative method of mixing is to pump the fresh surface water down into the salty water below. This will result in the algae being transported from the surface to the deep water where it will die from lack of light and then consume more oxygen in its decomposition.
There are many other similar “dead zones” in the world that can be treated in the same way. In many cases, the water is shallow enough so that strings of pumps can be anchored in place and left unattended for the duration of the seasonal “dead zone”.
The pumps may actually pay for themselves, because the algae will then be the basis of a healthy food chain and valuable fish and other marine products can be harvested from these well nourished areas.
Construction Details
The components of the pump are simple and inexpensive. The pipe can be made from PVC sewer pipe. This is available in fairly long lengths and is easily extended at any time by chemically welded couplings. The one way valve can be made by welding a coupling to one end of the main pipe, cutting the coupling in half, welding a short section of wider pipe whose inner diameter is equal to the outer diameter of the coupling to the coupling, cutting a series of slots along the length of the short wide pipe, placing in this pipe a ball which cannot fit into the main pipe, then capping the end of the wide pipe to make the ball captive. This will permit water to flow out of the main pipe but not into it. Placing this valve at the bottom of the main pipe pumps water downward, placing it at the top pumps it upward. There are other ways of making check valves (one way valves) also
One way of making the large float would be to pass the main pipe through a piece of rigid plastic foam encased in a shell made of fiberglass The float should be flat and wide so that it will follow the surface of the waves. The motion of the water in a wave is not simply up and down but in fact is circular. The float must therefore tolerate a lateral motion of the water with the same amplitude as the vertical motion. The float should be flexibly fastened to the pipe in such a way that the float can tilt relative to the pipe but not move vertically along it. For example, a gimbal mechanism provides this sort of coupling. It is also possible to use a flexible pipe or hose which permits the float to move laterally. In this case the hose should be under tension with a weight at the bottom and the float at the top always pulling. In any case, the float and the upper section of the pipe must be both strong and flexible so that they will not be broken by waves. The pumps are not a hazard to shipping since they can be made very visible by mounting a pole on the float and putting a bright flag on top and at night they are easily avoided if they have radar reflectors. Even if they are hit, they will break up and not damage the ship because they are made of light plastic.
The above ideas are only a few possibilities. There may many others that are also practical and useful. You are encouraged to give some thought to this and I would like to hear from you to get your reactions and ideas.
Bill Isecke
541 Queen Anne Road
Teaneck, New Jersey 07666
Isecke@yahoo.com
1 201 836 8403
