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UNDERWATER
VIBROCORING
 
SELECTING A VIBROCORER
 
CORETUBES,
LINERS, & CORE
RETENSION
 
BUOYANT-FRAME
vs RIGID FRAME
 
SPECIFICATIONS
 
OPERATIONS
FURTHER NOTES
 
 

SELECTING A VIBROCORER

Our various submersible models, described in the center pages and further commented below, essentially differ in terms of portability, mode of vibration, force, power requirements and depth rating. However, the performance of a vibrocorer depends in the final analysis upon the capacity of the sediment particles to move and give way to the coretube with less energy spent than received. Therefore the best results will always be obtained in unconsolidated, water-logged, heterogenous sediments.

P-3
  This lightweight, mid-size model operates in a vibro-percussive mode and is intended for standard survey work in a variety of sediments. It is compact, easy to handle and very efficient. Its capabilities approach, in many sediments, the performances of the more powerful P-5. It requires a 3-phase, 230 volt or 460 volt, 50-60Hz current. The P-3 is deployed with a separate non-armored electrocable to about 350 feet (100 m) depths, but requires a kevlar center cored cable for greater depths.
P-5
  Our most powerful model, the P-5 houses a pair of vibrator motors, the same model of vibrator motor as in the P-3, but in a contra-rotating configuration that doubles the vertical motion of the unit. Its twin cylinder housing and compact shape offers easier access to its internal parts - should, for example, the vibrator motor's wiring harness be switched between 230v or 460v current.
Special Procedures
  The P-5 has provision for injecting water under pressure at the top of the coretube in order to perform such special procedures as water-jetting and incremental coring.
*An important note about the power requirements:
  The P-3 and the P-5 require a 230-460 volt, 3-phase current. This is the voltage measured at the vibrohead. Voltage losses along the electrocable should be computed or tested, and taken into account. Usually, these motors will take an excess voltage of 10% above the rated voltage but may be damaged and even burnt if the voltage at the vibrohead is below 5% of this rated voltage. In view of such voltage loss, the 460v setting may be preferred for deepwater work.
 
PO Box 1030,
Poway CA 92074-1030
Phone: 858-679-7361