Production starts at the suction inlet pipe. This is why a proper feed is needed. If not totally free flowing, material must be excavated at a rate equal or greater than the pump can produce. This is often over looked, It all starts with the ability to fully feed the dredge pump to its capacity at all times. Secondly material must be transported hydraulically ” a Pump. ” On deck or hull pumps? Deck and hull pumps have quite a disadvantage to the underwater pumps. At 34 feet deep, water pressure is 14 psi. With a underwater pump there is no vacuum, just differential pressure. The underwater pump has a positive psi at suction inlet. On deck or hull pumps have to create vacuum. At 29 hg of vacuum = -14.7 psi in lift. Lift water and material to the pump with limited vacuum or feed the underwater pump with 14 psi or more head pressure. Therefore a underwater dredge is not limited by vacuum and can produce higher density with a unrestricted feed. Automation is a important factor in maintaining the hi density that underwater pumps can produce . Max density at constant fps = max hourly production. This is accomplished with pump rpm control. Dredge Works DWA-7 production system is the solution. Chain ladder or cutter bit. Cutter bits are preferred in most deposits. Only in the most demanding deposits chain ladders are used. A good rule for underwater pumps are this, at 50ft depth up to 30% increase in production, At 70ft + up to 90 percent increase in production is possible. At Dredge Works we build modern productive underwater dredges. Not dredges of the past. With global warming there is need for increasing efficiency in all industries including dredging. The cost has narrowed between the build of a hull dredge or underwater model. The pay off is very quick with the increased efficiency of a underwater dredge. In a new dredge build the only instance where a hull dredge or deck pump makes any sense is at shallow dredging.
Dredge Works = Productive, Innovative, Logical