Hawkeye Marsh Hawk - Manual (Page 2)

Hawkeye Industries Inc. 2
B.) Maintaining the Marshhawk Thief Hatch
B1.) Replacing the Pressure / Vacuum Gasket
B2.) Relubrication
B3.) Antifreeze Solutions
Remove the 12 #8-32 NC Socket Head Cap
screws with the 9/64 Allen wrench, freeing the
gasket retaining ring.
Using light pressure, push the vacuum plate
out of the way, and slide the gasket around it,
and off of the spider cage.
Generally, the more active the vent action of the hatch, the more frequent
relubrication should be performed. Specific relubrication requirements are
application specific, and are determined by the following variables:
► Chemical exposure
► Elevated pressure
► High flow velocity
► Elevated temperature
► Utilization (i.e. if hatch is primary relief)
Hawkeye factory-applies Dow Corning 4 Electrical Insulating Compound
to the vacuum and pressure gasket, and recommends the same com-
pound for any field relubrication.
►Excellent seal and release properties
►-57°C to 204°C
► Moisture Resistant
► 4.5% Bleed, 24 hr/200°C
► 1.4% Evaporation, 24 hr/200°C
► Non-toxic and odorless
It is not recommended to use any kind of antifreeze solution on a nor-
mally-operating Marshhawk thief hatch -- even as a preventative meas-
ure. However, if there is evidence of the hatch icing up, a compound with
suitable gasket compatibility is required. Please consult the supplied
chart and ensure that the solution used will not compromise the sealing
effectiveness of the Marshhawk Thief Hatch.
Align holes on new gasket with holes on spider
cage and retaining ring. With light an even
torque, replace the 12 #8-32 NC Socket Head
Cap Screws (I)
Remove the spider cage assembly from the hatch body as in Section A2, Step 1 before proceeding.
1.) 2.) 3.)
Hawkeye offers three gasket materials for the Marshhawk Thief Hatch:FKM
(Viton), FEPM (Aflas) and FFKM (Kalrez). Each with different properties,
temperature ranges and chemical compatibilities. Please ensure the se-
lected gasket materials suitable for your application prior to ordering a re-
placement. Call us for assistance. The following operating temperature
range table is provided for information only.
-50 0 50 100 150 200 250 300 350
Gasket Material
Antifreeze Solution FKM (Viton) FEPM (AFLAS) FFKM (Kalrez)
Methanol 4 1 1
Ethanol 3 1 1
Isopropanol 1 1 1
Ethylene Glycol 1 1 1
1 - Satisfactory 2 - Fair 3 - Doubtful 4 - Unsatisfactory
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