Emerson ROSEMOUNT OCX 8800 - Manual (Page 96)

Instruction Manual
IM-106-880, Rev 1.0
January 2007
OCX 8800
6-34
REPLACE TUBE
FITTINGS The OCX transmitter housings have special tube fittings that, if clogged or
damaged, must be replaced with the same type of fitting. The special tube
fittings have alpha or numeric codes etched on the fitting. Unetched tube
fittings are standard 1/4 inch, stainless steel fittings.
‘F’ Type Fitting
The ‘F’ type fitting is a flame arrestor fitting used in all OCX 8800
hazardous area housings. The flame arrestor fitting prohibits spark or
flame conduction from the housing. It requires a thread sealing compound
(Loctite 567) and at least five threads engagement.
‘13’ Type Fitting
This fitting is an eductor drive air fitting for the OCX 8800 hazardous area
housing. This is a 1/8 inch tube fitting with a built-in 0.013 inch restrictor
orifice. It seats in a threaded base port inside the housing.
‘R’ Type Fitting
The ‘R’ type fitting is a reference air line fitting for the general purpose and
hazardous area sensor housings. This is a 1/4 inch tube fitting with a
built-in 0.007 inch restrictor orifice.
Remove Tube Fittings The OCX construction includes pipe thread sealant to seal fittings in all ports
that pass through to an outer wall of the instrument housing base. Use the
following instructions to loosen and remove tube fittings that are secured with
pipe thread sealant.
1. Secure sensor housing (1, Figure 6-27) or electronics housing (2) in soft
(plastic, wood, or brass) vice jaws.
2. To soften the pipe thread sealant, use a propane torch to heat the tube
fitting (3, 4, 5, or 6) to 450°F (232°C), minimum.
3. While heating the tube fitting, use a wrench to apply removal torque until
the pipe thread sealant softens. Remove and discard the used fitting.
4. Use MEK or methylene chloride solvent to clean thread sealant residue
from the internal pipe threads in the housing. Refer to applicable MSDS
sheet for solvent handling precautions.
Use heat resistant gloves when removing a damaged tube fitting. The pipe threads are
bonded with a pipe thread sealant. The thread sealant softens at 450°F (232°C). The
heated parts can cause severe burns.