Dredge Operating

Unfortunately each operation in a dredge needs to be explained a great deal before another step is explained. When it is actually physically practiced it only takes a few minutes to get a dredge system working.

In reality priming the pump simply means that we have started the jet. To get the whole system working it is necessary to additionally prime the jet pump.

There are two basic spots for the ejector, which are above the water and under the water. All of the under water kinds are self priming and after the jet has been started, the system will work. The above water jet on the other hand, does need to be primed and there are many different explanations on how this can be accomplished.

One way is to slow the engine down and place your hand over the jet discharge as this will force the water down into the air space. Although this does work, anyone who has tried it will let you know how difficult it is to hold back a stream that is letting out 50 gpm, and you usually get soaked while doing so. In the case of an open sluice that does not have a pressure box this is fine but with pressure box system it is not that simple to do. After the system is working there is a problem of closing the lid.

Don’t despair though; the good thing is that there is an easier way to do this. You will first of all need to start the jet while ensuring the hose is completely under the water. Then hold onto the center of the flexible suction hose making sure the suction nozzle is kept under the water at all times. Rise up the center section of the suction tube just a few inches above the height of the base of the jet. If you do this with a soft action you will be able to acquire a siphon effect and the water will go up to the suction area of the jet pump with no cavitation. After this occurs the air and the water in the tube will be rapidly entrained and exited. The water will run into the low pressure area and the system will work.