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6X-
1092B
5.1.1 Schrader Valve
The Schrader Valve is used to pressurize the housing. To maintain pressure in the barrel, add dry nitrogen
to approximately 5 psi (34 kPa).
5.1.2 Pressure Relief Valve
The Pressure Relief Valve limits the maximum pressure in the camera head to approximately 20 psi
(138 kPa).
CAUTION:
Exceeding 20 psi can cause damage to the relief valve.
IMPORTANT:
Due to high temperature, high altitude, or other reasons, the pressure inside the camera
head may increase. The pressure relief valve opens when pressure rises above 20 psi (138 kPa), allowing
excess internal pressure to bleed off. After the camera system returns to normal conditions, the internal
pressure must be checked and the camera housing must be pressurized with dry nitrogen to bring the pres-
sure back to approximately 5 psi +/- 1 psi. See Section 5.1.3 for pressurization procedure.
5.1.3 Pressurizing Procedure
The following items are required for pressurizing:
•
A tank of dry nitrogen with a regulator
•
A hose with an air chuck to connect to the Schrader valve
NOTE:
Preferred gas for pressurization is dry nitrogen. Argon is an acceptable substitute. Do not use com-
pressed air, as it may contain oil, moisture, or other contaminants.
Below are steps for
recharging
the camera housing:
1.
Set the regulator gauge to approximately 7-10 psi. (A regulator kit ER2914 is available for pur
-
chase.)
2. Remove the plastic tubing from the pressure relief valve if purge is required.
3.
Remove the cap from the Schrader valve, place the air chuck on the Schrader valve and fill the
housing with nitrogen.
4. Carefully lift the poppet on the pressure relief valve and purge the camera housing with dry nitrogen
for a minimum of one minute by manually lifting the relief valve on the rear plate while injecting the
dry nitrogen into the Schrader valve.
CAUTION:
Do not use a sharp object to open the pressure relief valve. Use care to avoid damage or
contamination of the valve seat.
5.
Remove the air chuck and verify with a pressure gauge that the pressure is 5 psi +/- 1 psi. Press the
pin in the center of the Schrader valve to release extra pressure from the barrel if needed.
6. Firmly install the cap on the Schrader valve to get a good seat. Cap is required for a proper seal.
7. Install the tubing back on the pressure relief valve if it was removed.