USA: Ellicott’s Application for New Patent Gets OK

Ellicott's Application for New Patent Gets Nod

The U.S. Patent Office has approved Ellicott Dredge’s latest application for a new patent named Slurry Pump with Adjustable Liner.

This invention relates generally to a slurry pump, and, more particularly, to centrifugal slurry pump for dredging. The invention uses electronic sensors to measure the gap between the impeller and the front head liner. Then it uses small hydraulic cylinders or small electric motors to advance the front head liner closer to the impeller to reestablish the factory gap setting.

This can be done on demand by activating a switch or button on the control stand, or if the dredge has a programmable logic controller (PLC), it can be a sequence in the start-up procedure.


In a centrifugal pump, maintaining the gap between the impeller and front head liner is critical to the efficiency of the pump. When the pump is put into operation, the front head liner and impeller will wear. How quickly this wear takes place is dependent upon the type of material being pumped, the more abrasive the material, the faster the wear.

In traditional pumps the most commonly used method to reset the gap to the factory setting is to remove the front head, remove the impeller and add copper gaskets on the impeller shaft to the thickness required reset the gap.

This procedure takes time and requires a crane or some other type of lifting device, as the head and impeller are heavy.


Downtime, particularly in the mining industry is very costly. For example, the Cooljarloo dredge in Australia, which mines heavy minerals, (titanium dioxide feedstock) averages 22.5 hours of operation, 365 days per year. This invention saves time because the pump adjustment does not involve taking the pump apart. Production is vital to all dredging projects.

As the pump begins to wear, efficiency is reduced. This invention maximizes production by retaining the factory set gap almost 100% of the time.


April 23, 2014