- SHMRC Beach Laboratory
-
-
-
|
|
-
The Poseidon Dynamic Test System
-
- The Poseidon Dynamic Test System (PDTS) is a versatile platform
that allows exposure of flat panels on a rotating frame in the
middle of the sea. Supplied with electric power through an
underwater cable from the shore laboratory (photo on left), the
motors rotate the panels horizontally at various speeds ranging
from 15 to 25 knots. The erosion rate as result of the fluid
shear forces can be determined at each specific speed. The
figure below shows the erosion of a self-polishing copolymer
coating at different speeds.
-
-
- The graph shows the erosion of
coating at various velocities in the dynamic test system
- at month 3 of continuous exposure.
The erosion rate is velocity dependent.
- Although static immersion test is sufficient to measure the
antifouling characteristics of a particular coating, it is not as
reliable in determining the performance of the entire coating
system. In many cases, panels that do well under static, fail
when exposed to shear stress in the PDTS machine. Testing in
advance enables reformulation or redesign of the top coat, primer
and application procedures to meet customer expectations.
The comparison of same coating exposed for two months in both
immersion tests. The difference in the results was compelling.
- Static Immersion
Dynamic Immersion
|
|
Video of the dynamic machine in operation.
|
|
- POSEIDON DYNAMIC TESTING SYSTEM (PDTS) NOW ON ITS 6TH
YEAR OF OPERATION
- MARINE EXPOSURE
PROCEDURES AND COSTS ●
TUTICORIN
BAY, INDIA
-
- Poseidon Dynamic Testing
System (PDTS) now makes it possible to simulate the
erosion rate of marine coatings in a moving vessel.
This new procedure enables simultaneous evaluation of
the erosion rate at various fluid shear forces using flat
panels. This
system was presented in 2003 to the Society of Protective
Coatings at its conference in New Orleans and at the
Federation of Societies of Coatings Technology's annual
meeting in Philadelphia. For a PDF copy of this report,
please click on the icon.
-
-
In this procedure, flat metal panels
are placed on a horizontal
plane on
a rotating disc immersed in the open sea,
which causes erosion on the flat
panel at various ship speeds
of up
to 40 miles
per hour. The description of
our marine research exposure stations and the dynamic testing
system can be found in detail on the Poseidon website
www.poseidonsciences.com.
-
-
-
The PDTS
machine uses a standard flat steel panel supplied by ACT Test
Panels, LLC (Michigan) with the following specifications:
Steel Panels
APR53743
ACT HRS l - 04x06x071
Steel Grit Blast Both Sides; 2 Mil Profile
(ndividually wrapped in VCI paper to prevent corrosion)
- Fiberglass
-
- APR53940 Fiberglass 04x06x1/8" Plain FRP - Smooth Finish
The panel can
be purchased at the standard size
of 4 inches by 6 inches (101.6 mm x 152.4 mm).
Contact Brad Kimpell at ACT Test Panels
(1-517-439-1485,
www.acttestpanels.com) or by email at
brad.kimpell@acttestpanels.com.
The test
panel may be coated on one or both sides
and submitted to Poseidon for installation in the machine.
As shown in the figure
(above), the position of
the panel in the
rotating disc will determine the relative velocities of the
seawater. We suggest that the client submit one (1) panel for each of
the three (3) positions to obtain the full range of velocities
possible. It is also
advisable to do the test in duplicate.
Combination
of Dynamic and Static Immersion Testing
The PDTS machine offers the versatility of
removing the panels at any client-specified period of exposure
and subjecting the panel to static immersion.
This enables the evaluation of the performance of the
antifouling coating after a period of fluid shear stress and
erosion rate. Ideally,
multiple panels are subjected to the fluid shear stress of the
PDTS machine and certain panels may be removed after various
periods of time or at equivalent travel distance for static
immersion.
Inspection
Schedule
The test panels are inspected by removing the
panel at a specified period of time (example: after 1 month)
or upon reaching the equivalent distance (example:
10,000 miles). The
testing program will be subject to the specifications of the
client.
Testing
Period
The minimum testing period is three (3) months.
Thereafter, the client may terminate the study or any
particular set of panels at any time by giving ten (10) days
advance notice.
Inspection
The client receives digital photographs via electronic
mail of each panel (front and back side) within 10 days from
the inspection date. Measurement
of coating film thickness of metal panels is conducted at a
client-specified schedule. Measurements consist of three (3) positions along the
midline of the panel on both sides. Since the fluid shear
forces experienced by the panel vary depending upon the
distance from the center shaft, the film thickness
measurements represent erosion rate at three (3) different
velocities for each panel.
Cost of Testing
Please inquire by email for costs of tests by providing number
of panels, inspection schedule and whether it is an alternating
static-dynamic or continuous dynamic test.
 Back
to top
|
