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C02 Pro GTD Pro 02 Pro N2 Pro

Gas Tension Device: Standard and Hurricane models

View the Standard Model         View the Hurricane Model

The PSI GTD-Pro is said to be the most accurate and stable dissolved gas sensor ever developed. The GTD-Pro measures the sum of the partial pressures of dissolved gases in water. It uses a small sample volume that equilibrates with dissolved gases through a semi-permeable membrane. Measuring the pressure of the equilibrated gases gives the gas tension (the sum of the partial pressures or, more accurately, fugacities of all dissolved gases).

Our GTD-Pro has an accuracy of better than 0.02 % per year, and a precision of microbars. One of our standard GTD-Pro's was deployed numerous times in locations that included the Labrador Sea, the Equatorial Pacific, and the North Pacific. After six years of demanding use, the instrument was re-calibrated and found to have drifted from its original calibration by less than 0.01% per year.

What is the difference between the Standard GTD-Pro and the Hurricane Model (HGTD)?

The primary differences between the Standard GTD-Pro and the HGTD are size, weight and versatility in configuration. The PSI pumped, fast interface (patent pending), is a normal feature of the HGTD, and is available as an option for the Standard GTD-Pro. This highly innovative interface, which has been tested to 1000 meters depth, can be configured in various ways to fit the user's application (e.g. in a canister separate from the electronics housing). The table to the right provides a summary of the differences between the Standard and HGTD models. For more details about the Standard GTD-Pro and HGTD, click on the links above or contact PSI.

Spec Comparison

Feature GTD-Pro HGTD*
Length: 12.5 in.
(31.8 cm)		 9 in.
(22.9 cm)
Diameter: 4.5 in.
(11.4 cm)		 3.25 in.
(8.3 cm)
Weight (air): 15.5 lbs.
(7 kg)		 3.6 lbs.
(1.6 kg)*
Weight (water): 7.436 lbs.
(3.38 kg)		 1.32 lbs.
(0.6 kg)*

*sensor housing only

Available Options:

GTD-Pro
  • Pumped Delrin plenum: for use with the flat interface to reduce the time constant for equilibration. = 10 minutes depending on flow rate
  • Tubular pumped fast interface: alternate fast interface for our Standard PSI GTD-PRO. = 3 minutes depending on flow rate

HGTD
  • Comes fitted with our tubular pumped fast interface. = 3 minutes depending on flow rate