The purpose of this innovation is to simulate the space temperature environment onto a fluid disconnect. This environment is to be maintained for a long period of time (48 hours) at a controlled temperature [6 ±2 °F(≈–14.4 ±1.1 °C)] to determine if temperature is causing leakage through the disconnect.

The test apparatus includes a 50-liter, 22-psig (≈253 kPa) liquid nitrogen dewar; an insulated ¼-in., 10-ft (≈6-mm, 3-m) flexhose assembly with a 0.052-in. (≈1.3-mm) exhaust orifice; 3-in. diameter (≈76.2-mm) tube 3 ft (≈0.9-m) in length constructed of G10 fiberglass material with GORE-TEX face seal; a tube location spacer made from G10 material; a temperature controller; Type K thermocouples; 100-psig (≈791-kPa) relief valves; a cryogenic solenoid valve; and a temperature readout display.

A controlling thermocouple is affixed to the exterior body of the fluid disconnect, and reference temperature sensors are affixed to the back side of the disconnect and adjacent hardware. An insulation tube is installed over the fluid disconnect, pressed against the panel face, and restrained to maintain a seal. A liquid nitrogen dewar is used with a cryogenic solenoid valve connected to the liquid side of the tank. Relief valves are installed between the dewar shutoff valve and the solenoid valve, and at the outlet of the solenoid valve, to protect against pressure rise due to liquid nitrogen boil off. A flexhose assembly with insulating material on its exterior is connected to the outlet side of the solenoid valve, and an orifice is installed in the flexhose outlet to control the vapor exhaust. The flexhose outlet is placed within the tube location spacer to direct the vapor to the face of the fluid disconnect with the exhaust a suitable distance away from the component to be cooled [approximately 12 in. (0.3 m) for this application]. The desired temperature with control band is programmed into the temperature controller, with hi/low alarm limits to indicate out-of-tolerance conditions.

The liquid outlet valve of the dewar is slowly opened, and the liquid/vapor flows through the assembly and onto the fluid disconnect, causing the component to cool. When the desired temperature is achieved, the temperature controller sends the signal to the solenoid valve to stop the flow. The temperature is maintained within the desired range by the opening and closing of the solenoid valve that, in turn, starts and stops the flow of liquid/vapor.

This work was done by Kevin Jumper, Brian Hunter, and Walter Hatfield of ASRC Aerospace Corporation for Kennedy Space Center. For more information, contact the Kennedy Space Center Technology Transfer Office at 321-867-5033. KSC-13225

NASA Tech Briefs Magazine

This article first appeared in the September, 2014 issue of NASA Tech Briefs Magazine.

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