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Automated Dredging Systems
for Solids Control Dredging
LWT PIT HOG™ SENSE SYSTEMS
RADIO, SOLIDS & DEPTH SENSING

RADIO REMOTE SENSE™
LWT has designed this system to allow remote control of the dredging operation with a portable radio system. RADIO REMOTE SENSE™ controls the functions of speed and direction of the slurry pump, auger and travel, power on/off and the dredging depth. The hand held control panel may be operated at distance of at least 2,000 feet from the dredging unit, with three revolving lights on board the dredge indicating when the auger, pump, and travel motors are running. As LWT integrates electronic control systems on its PIT HOG™ equipment, this control system may be used to drive either electric or engine power plants.

SOLIDS SENSE™
Incorporation of LWT's SOLIDS SENSE™ solids control dredging system will automatically work to maintain delivery of a constant solids density. Set the desired solids density concentration level from an adjustable range and the control system will continually respond to maintain that level. The SOLIDS SENSE™ control system reacts faster than an operator and virtually eliminates the need for hands on operator control while dredging to optimize solids production.

BOTTOM SENSE™
Use LWT's BOTTOM SENSE™ system to protect pond bottoms and liners. Switch on BOTTOM SENSE™ and the sensing system will automatically raise the auger head when the bottom is contacted, lower the head when it senses that the bottom is not present, following the bottom contour.

AUTO SENSE™
Cable stops are set on the traverse cable at the limits of the area to be dredged. When the dredge contacts the forward stop the unit will automatically stop forward travel, raise the auger, slow the slurry pump speed, and reverse at a high rate of travel until it makes contact with the rear stop. The dredge will then lower the auger head and shut down (or alternatively wait for a command to go forward.)

LATERAL SENSE™
When the project application calls for automated lateral movement LWT can incorporate and control this function by installing an on board radio system.

COMBINE SENSE FEATURES FOR TOTAL REMOTE CONTROL BY RADIO
Combine these features for efficient automated dredging, while minimizing labor. The dredge travels forward with the SOLIDS SENSE™ system controlling production and travel across the pond, while automatically maximizing solids. BOTTOM SENSE™ protects the pond bottom and follows pond contours. LATERAL SENSE™ is combined with AUTO SENSE™ and the other systems described above for complete control cable-free automation. Utilizing these features effectively minimizes the labor requirement and the hands-on intensity of any project while maintaining optimum production levels.

CONCEPT FOR AUTOMATED SOLIDS CONTROL DREDGING
Totally automated, and remote operations are achieved with low voltage electronic controls. A PLC (programmable logic controller) is programmed to provide control over the dredges automated functions and control loops, minimizing labor and maximizing production of solids at the set flow rate. This system is ideally suited for providing material to both de-watering or continuous process systems. LWT supplies components and will provide customized operational features to meet your specific operational needs.

AUTOMATIC REMOTE CONTROL DREDGING
Settled solids are excavated from the lagoon bottom by the LWT dredging unit which may be operated either remotely on shore and/or manually on board. The units forward and reverse travel, as well as its side to side lateral movements, are totally automated by a steel rail system located on the ends of the lagoon.

DISPLAY AND CONTROLS
With a lap top computer or desk top computer, the owner can observe a visual graphical image of the system's entire operations while working, and record operating data.

Controlled by the PLC, the electronic control system directs the dredge to make "sweeps" covering the entire lagoon, automatically without an operator. The dredge is programmed to travel forward at a controlled speed, taking eight foot wide passes through the solids bed. When the dredge comes to the end of the run it automatically goes into high speed reverse, slows the pumping rate, and travels until it reaches the initial starting point for that pass. The dredge then raises the auger head, shifts laterally to the starting point of the next pass, lowers the auger head, restores the slurry pump speed and moves forward to continue dredging. Incorporation of LWT's BOTTOM SENSE™ will "float" the auger head and allow it to follow the bottom contour or stay a set depth off the bottom.

AUTOMATIC SOLIDS AND FLOW CONTROL
The solids/flow control system is also controlled by the PLC. The dredge travel function is electronically linked to the density meter providing an electronic signal proportional to the density of the slurry, to the PLC. The PLC control look compares the incoming signal to the adjustable solids set point and continuously regulates the solids delivered by the dredge. The same principle is used to regulate the flow volume. An electronic magnetic induction flow meter provides feedback to the PLC control look which, in turn, regulates the flow delivered from the dredge slurry pump.

The NEMA rated control panel for the Automated Rail Lateral Move System has displays and input controls for the speed and direction of the slurry pump, auger and the traverse system. An alpha-numeric readout displays slurry density, slurry flow rate, and shutdown fault messages. The display may optionally show the location of dredge in the pond, depth of operations, slurry pump pressure or other required functional feedback data. This system is compatible for a continuous process system or supplying material to a tank for batch feeding a dewatering system. For a batching application, level monitors may signal the dredge to run until the tank is full, then turn off until the low level sensor signal turns the dredge back on again.