High Pressure Hoses & Dredges

When there is a really long suction or high pressure hose where the amount of air is considerably above, it is suggested to get rid of as much of the air as you possibly can by filling the air hoses with water before you turn on the engine. This is specifically true of the movable ejector type that usually has a pressure hose that is fifteen feet or more. Finally what can be done if there is difficulty with priming is to fill the whole system with water before turning the engine on. This will only leave a teensy amount of air in the pump to be expelled. Unfortunately it is necessary to explain every dredge operation a great deal before another step is explained. However 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.

Dredge ejector and solutions
There are two basic spots for the ejector and this is above the water and under the water. All of the under water types are self priming and after the jet has been started, the system starts to 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 on top of the jet discharge as this will force the water down into the air space. Even though 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 frequently 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 setback of closing the lid. On the upside though, there is a simpler way of accomplishing this. You will first need to start the jet while making sure 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. Lift 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 obtain a siphon effect and the water will go up to the suction area of the jet pump without cavitation. Once this takes place the air and the water in the tube will be quickly entrained and exited. The water will run into the low pressure area and the system will work.