2110 70 Ave NW, Edmonton, AB Canada T6P 1N6 phone: (780) 490-4295, fax: (780) 490-4290REV C1 NOVEMBER 2013

www.hawk-eye.com 1-800-910-HAWK (4295)

Vapor Control > Tank Relief Vent

Marsh Hawk TRVThe Marsh Hawk is a deep-set pressure and vacuum relieving vent for atmospheric tanks. With re-cessed seals for both pressure and vacuum relief, the Marsh Hawk resists freezing, providing reli-able year-round operation.

Above: Marsh Hawk TRV

Right: Marsh Hawk TRV withcover open, revealing thedeep-set internals.

Design

Construction

Flexibility

Both the pressure and vacuum seals are situated over 9” inside

the tank, using the intrinsic heat of the product to prevent the

vent internals from freezing. Pressure release settings are eas-

ily adjustable, from 2 ozsi to 16 ozsi (18 - 32 ozsi with double

weight spring), using proprietary pressure spacers. Flutter and

leaks are eliminated via guided spring and seal pallet. The re-

movable internals allow for tank access and simplify seal main-

tenance.

Rugged stainless steel and aluminum construction make the

Marsh Hawk TRV perfect for sweet or sour gas applications.

The Marsh Hawk TRV is available with a variety of seal materials

and coatings to suit the vent to any application. Additionally, the

field-adjustable pressure relief setting makes the Marsh Hawk

TRV a flexible tank vent solution. The Marsh Hawk can replace

a thief hatch on an 8” API flange, and many mounting adapters

are available to suit other common tank connections. An op-

tional pipe-away adapter is available to pipe vapors to contain-

ment or flare.

MaterialsComponent Standard Optional

Body & Lid AA356.2 n/a

Valve Internals AA356.2 & AA6061 n/a

Internal Fasteners 316 SS n/a

Pressure GasketFKM (Viton)

See Chart back pageVacuum Gasket

Pressure SpringStainless Steel Inconel

Vacuum Spring

Pressure (ozsi) Force (lb)4 56 78 9

Pressure (ozsi) Force (lb)12 1416 1932 38

2110 70 Ave NW, Edmonton, AB Canada T6P 1N6 www.hawk-eye.com

Manual Relief Option

Operating Forces

The Manual Relief Option allows an operator to manually actu-

ate the vent, relieving pressure in the tank to allow safe removal

of the spider cage internals. Additionally, manual actuation al-

lows any accumulated condensation collected on the valve pal-

let to be drain back into the tank without having to rely on the

tank drawing vacuum.

The large mushroom button is connected to the vacuum disc via

a spring-loaded poppet. Pressing down on the button opens the

vacuum disc, allowing pressure to escape. The button and pop-

pet are supported independently of the vacuum disc, and as

such do not affect the vacuum or pressure relief performance of

the vent.

Above: Marsh Hawk TRV withManual Relief OptionInset: MRO Spider Cage

Hard Anodized OptionFor situations requiring improved corrosion resistance above the

standard Marsh Hawk, we offer a Hard Anodized Option. An-

odizing is an electrochemical process which increases the thick-

ness and durability of aluminum’s naturally occuring oxide layer.

All aluminum components of the vent, including the body and all

internals are anodized to meet MIL-A-8625F Type III Engineering

Hardcoat. The anodization slightly darkens the cast compo-

nents, and adds a slight bronze colour to the machined compo-

nents.

The anodized Marsh Hawk will exhibit improved resistance to

moderate saline, as well as acetic, boric & nitric acids. For pro-

longed exposure to concentrated brines, high-chloride ion con-

tent, or hydrochloric, sulphuric or other acids not listed here, it is

recommended the Severe Service Coated Option be used.Above: Hard Anodized Marsh Hawk TRVInset: Hard Anodized Spider Cage

Marsh Hawk TRV

phone: (780) 490-4295, fax: (780) 490-42901-800-910-HAWK (4295)

Severe Service Coating OptionFor situations demanding the highest corrosion resistance com-

pared to the standard and anodized offerings, consider the

Marsh Hawk with the Severe Service Coating Option.

The body and lid of the Marsh Hawk are coated in a red epoxy

material, providing resistance to strong mineral acids, including

hydrochloric, hydrofluoric and sulphuric acids, high chloride ion

solutions, inlcude aluminum chloride, potassium chloride and

brine solutions, as well as many organic compounds common in

the oilfield.

The internals of the Marsh Hawk are coated in a proprietary

black Teflon PFA material, providing the spidercage the same su-

perb chemical resistance properties as Teflon . Above: Fusion-bond Epoxy Coated BodyInset: Teflon Coated Internals

Marsh Hawk De-icing System

Related Products

The Marsh Hawk De-icing System allows an operator to spray a

deicing or antifreeze agent* right onto the internals of the vent

from ground level.

The system consists of the specially designed nozzle, 36 ft. of

hose, swivels, check valve and a 1/4 NPT male connection for

ground level. Optionally, the system can be furnished with a

manual hand pump and quick connect hose fittings.

All Marsh Hawks manufactured since July 2010 feature a pair of

1/4 NPT ports on the body to accomodate the deicing nozzle.

Marsh Hawks manufactured prior to this date will require drilling

and tapping a 1/4 NPT port on the body, just under the resting

position of the cover.

Above: Marshhawk De-icing System assembly.Inset: Detail of nozzle and swivel hardware.

* Refer to the Marshhawk Installation & Maintenance guide for recommendedantifreeze agents.

► Risers, for connecting to sloped roofs or con-

nections other than 8 API.

► Pipe Away, for ducting away any emissions

from the vent..

Ordering Information

Marsh Hawk TRV

2110 70 Ave NW, Edmonton, AB Canada T6P 1N6 phone: (780) 490-4295, fax: (780) 490-4290www.hawk-eye.com 1-800-910-HAWK (4295)

MH Marshhawk TRV

Pressure Relief Setting2 to 16 ozsi in 2 ozsi increments1 ozsi increments & 18 - 32 ozsi availableNote: Vacuum relief fixed at 0.4 ozsi

Seal MaterialV FKM (Viton)F eFKM (Foam Viton)A FEPM (AFLAS)K FFKM (Kalrez)T ePTFE (Expanded Teflon)

Manual Vent Relief0 No Manual Relief1 Manual Relief System

Spring Material0 Stainless Steel1 Inconel

Coating0 Bare1 Anodized (Type III Hardcoat)2 Severe Service Coating

MH Sp G P- - C M

Settings Options

Relief Settings

2 - 32 ozsi

ManualRelief

InconelSprings

Viton,AFLAS orKalrez Seals

De-IcingSystem

HardAnodized

Severe Service Coating

Sp

C

Schematic cutaway shown without lid for clarity.

P

G

M

Bold Type indicates Standarditems.