ADC 150-2257-01, Руководство пользователя

Страница: 30 / 52

Appendix A - Technical Reference 150-712-200-02
22 July 26, 2000 HRE-712 List 1 and List 2
HRE-712 L
IST
1 V
ENTED
-
TO
-P
RESSURIZED
C
ONVERSION
P
ROCEDURE
The following instructions are for converting the HRE-712 List 1 gel-filled vented enclosures to external
pressurized enclosures.
The HRE-712 List 1 enclosure can be converted to a pressurized housing that uses a continuous, local air pressure
source. The conversion requires replacing the breather-vent valve with an optional pressure-relief valve. The
breather-vent assembly, located in the base pan, allows the internal pressure to equalize with the outside pressure.
The optional pressure-relief valve (provided in the shipping kit) replaces the breather-vent valve and prevents over
pressurization when pressurizing from an external air source. The HRE-712 List 1 is equipped with a gel-filled
cable, which precludes pressurizing through the cable stub.
Use the following instructions, with Figure 1 on page 2 , to convert the HRE-712 List 1 enclosure from a vented
housing to a pressurized one:
1 Locate the breather-vent valve on the bottom of the housing. Figure 3 on page 5 shows the metal valve located
adjacent to the cable stub inlet.
2 Remove the valve by unscrewing it in a counterclockwise direction.
3 Save the vent or store it inside the housing for future conversions.
4 Check the threaded hole for debris and clean it if necessary.
5 Remove the pressure-relief valve from the plastic bag. Verify that an O-ring is installed on the threaded end
of the valve.
6 Carefully place the threaded end of the air-pressure cutoff valve into the threaded brass fitting from which the
breather-vent assembly was removed.
7 Hold the valve straight and push it into the hole. Turn the valve clockwise to screw it in place.
8 Handtighten the valve until it is tight against the gasket material.
The housing is now ready to be pressurized either through the T-valve’s Schrader air-stem valve, which accepts
a standard tire valve chuck, or through its external air-intake stem, as shown in
Figure 1 on page 2 . A desiccant
bag is also included with the air-pressure cutoff valve in the HRE-712 List 1 shipping kit. Remove this bag and
place it in the HRE-712 prior to pressurization.
1 Attach a
1
/
4
-inch (.64 cm) inner diameter by
3
/
8
-inch (.83 cm) outer diameter plastic tube (not included) to the
1
/
4
-inch (.64 cm) air-intake stem T-valve.
2 Secure the tube to the valve with the hex bolt and ferrule.
Static pressurization requires monitoring and maintenance as the pressure decreases over
time.
If there are any signs of resistance while screwing the valve into place, you could be
cross-threading the part. Remove the valve and restart.
The tube and fitting assembly required for the conversion procedure is also called an Express
Air Connection Fitting.
The plastic tube is not supplied by ADC.