Appendix H - Ctd Maintenance - idronaut Ocean Seven 304Plus Operator's Manual

APPENDIX H – CTD MAINTENANCE
H.1 FOREWORD
The IDRONAUT sensors are all pressure compensated and, in particular, the physical sensors
(conductivity, temperature and pressure) can last several years, if properly used. They are high-
quality sensors and they are well known by oceanographers to measure salinity with great accuracy.
Even the chemical sensors: pH, dissolved oxygen and redox, if thoroughly maintained with their
respective hydrating caps and solutions, can last some years. The aim of this appendix is to make
recommendations, based on our experience, on cleaning, care and storage of the IDRONAUT chemical
and physical sensors installed in the OCEAN SEVEN 3xx CTDs. Most of the recommendations below
reported are taken from the OCEAN SEVEN 3xx Operator's Manuals.
This appendix is divided into two sections:
• OCEAN SEVEN 3xx CTDs general cleaning.
• Sensor dedicated cleaning and care.
H.2 GENERAL CLEANING
After use, the OCEAN SEVEN 3xx CTD must be always washed to remove any salt water residual or
dirtiness. Deionized water, distilled water or fresh, tap water can be used. Verify that fresh water
used to clean the CTD is not contaminated even by any small quantity of oil. In this case, do not use
this water.
In case the CTD body or the sensors have any visible deposits of marine growths, we recommend
cleaning the CTD body with some liquid soap and a small "soft" brush to clean the sensor bulkheads
between the sensors. In case the OCEAN SEVEN 3xx sensors had been exposed to oil, we suggest
using the Triton X-100 (solution at 1-2 %) in place of the liquid soap.
Alternatively to the "Liquid soap" or the Triton X-100, it is possible to use a solution of 70% isopropyl
alcohol or a solution of 1/4 cup of bleach in 4 litres of tap water.
In case the OCEAN SEVEN 3xx CTDs is used in wastewater, it may be disinfected with 5% Lysol if
this is more convenient to the user.
H.3 SENSOR DEDICATED CLEANING AND CARE
H.3.1 Pressure sensor
The pressure sensor is an almost maintenance-free device which
meets the highest reliability standards thus reducing the chance of
possible failures. The pressure transducer is located in the middle of
the CTD bottom flange, protected by a plastic black cap. Every five
years, ask IDRONAUT to remove the pressure sensor plastic o-ring
cap and brush any sediment using a soft-haired brush. Remove excess
grease using a tissue or cotton bud. Take care not to damage the very
thin pressure sensor diaphragm. Gently apply a thin layer of grease
on the sensor surface to minimize any device corrosion. Ensure that the holes in the pressure sensor
cover are not blocked with sediment.
IDRONAUT – Brugherio (MB) OCEAN SEVEN 304Plus CTD
70
12-2015