OOTTV

Gimpel® Oil Operated Trip Throttle Valve (Offset Body)

Dresser-Rand acquired the
Gimpel valve business in April,
2007. Gimpel products include
a line of trip, trip throttle, and
non-return valves to protect
steam turbines and related
equipment in industrial and
marine applications

The Dresser-Rand Gimpel® oil operated trip throttle valve (OOTTV) is designed to
close (trip) after a loss of oil supply pressure, and not reopen until oil pressure has
been re-established.
The OOTTV (offset body) is recommended for steam turbines driving the main
process compressors in API-612 critical service applications in chemical and
petrochemical plants, refineries, and synchronous generators in power generation
facilities with normal inlet steam pressure above 900 psig (63.4 kg/cm2g). The offset
body provides a more streamlined flow path than a globe body valve, resulting in
reduced turbine inlet throttling loss. (Offset is defined as the separation dimension
between the horizontal center-lines of the inlet and outlet connections of the valve
body.)
The OOTTV is designed to use hydraulic pressure supplied by the turbine control oil
system to compress a fully enclosed, large diameter trip spring. This trip spring allows
an OOTTV to typically produce four to 10 times the closing force of a mechanical
latch-type trip throttle valve during tripping. The OOTTV is designed with pull-to-close
operation and features a back-seated stem that results in no continuous valve stem
leakage when the valve is operating in its normal, fully-open position. The OOTTV
can be furnished in several body styles and assembly arrangements, and is normally
installed with the valve stem in a vertical position.
The design incorporates more than 25 years of experience with proven features and
technology including:
• ANSI nominal pipe sizes (NPS) four to 20 and pressure classes 1500 and 2500
• Steam temperature up to 1004°F (540°C)
• Tripping in 0.3 second, or less
• Poppet design with pilot valve capable of opening against full differential steam
pressure
• Cast alloy steel, offset valve body with bolted cover available in straight-through,
corner body, and top inlet flow arrangements
• Raised face (RF) and RTJ (ring-type joint) inlet and outlet connections available
• RF and RTJ valve body drain connections available
• RF flange valve stem leak off connections standard
• Chrome moly steel main disc and valve seat – seating contact surfaces overlaid
with stellite
• Stainless steel, integral, replaceable, steam strainer basket
• Handwheel provides throttling during start-up
• Low pressure (100 – 200 psig) and high pressure (1,100 – 1,600 psig) hydraulic
actuators available
• Factory hydrostatic test for strength, porosity, and seat leakage
• Factory operational test without steam
• Final surface inspection
Optional features include:
• Limit switches to monitor valve stem positions
• Solenoid exerciser for remote, on-line exercising
• Electric actuator for remote valve operation
• Protective cover (for harsh climate installations)
• Temporary start-up screen with spare cover gasket
• Blowdown kits