Croll-Reynolds Turbine Bypass Valves/Systems are manufactured in technical collaboration with Kauer Engineering of
Germany, for industrial and utility power plants. We manufacture custom engineered valves with plasma nitride trim
and highly reliable operational designs which are robust and ideal for tough critical service applications.
For over 25 years our chief designer, Gunther Kauer of Kauer Engineering designed Turbine Bypass Desuperheating
Systems for Latentenegerie GmbH & Co. KG, Sempell GmbH (now Babcock - Sempell), C.H. Zikesch GmbH and Bopp & Reuther
GmbH. He was also a member of the DIN standardization committee for stress calculations on special valves.
Croll-Reynolds/Kauer designs systems for the hypercritical
conditions of massive pressure drops and sonic velocities, at a competitive price.
INTRODUCTION
Turbine Bypass Valves play a major role in Power Plant applications. Within a period of twenty-four hours, a Power
Plant may be required to operate at minimum load, increase to maximum capacity for major part of the day, immediately
cut back to minimum load and then back to maximum capacity. Bypass Systems permit unit-start up and unit-shutdown
for critical heavy components in boilers and turbines. Bypass Valves are supplied with hydraulic, electric or pneumatic actuators as per the process requirements, along with complete control systems as an option.
FUNCTIONS OF HP & LP BYPASS VALVES
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To perform quick and economic start up, including cold start, warm start and hot start.
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To operate the boiler with the turbine shut down
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To perform warm and hot startup in a short time after a trip to bring the unit back to load.
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To run the unit down to house load.
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To perform real "two-shift operation".
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To avoid condensate losses to the atmosphere and reduce the start up noise.
APPLICATIONS
There are two basic applications:
Bypass Systems which are occasionally in operation. Among these there are startup and shutdown conditions and
emergency conditions.
Bypass Systems which are permanently in operation, for example for process steam or heating applications.
ACTUATORS
Bypass Valves can be supplied with Pneumatic Piston, Electric or Hydraulic Actuators and can be supplied
with power packs with complete control systems.
MATERIALS
For most sizes, castings or forgings in Carbon and Alloy Steel can be supplied. For large sizes, units are
fabricated.
Bypass Valves are normally supplied with butt weld ends, but can be supplied with flanged ends.
DESIGNS
BYPASS VALVE WITH ATOMIZING NOZZLE AT THE OUTLET
The atomizing nozzle is positioned at the outlet of this valve. The atomizing steam is extracted from the
high-pressure side of the valve shortly downstream of the valve seat (i.e. at the point of extraction the
pressure throttling is not yet initiated). The atomizing steam is carried to the nozzle via an external line.
No additional steam valve is required.
ADVANTAGES:
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Excellent spray water evaporation using the high mechanical energy of atomizing steam
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Excellent temperature control as close as 3 - 4 deg. C. above saturation.team.
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Short straight outlet line required even at low steam velocities.
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High turndown ratio of 30:1.
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Ideal for large amount of spray water.
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Separate steam atomizing valve not required.
BYPASS VALVE WITH ATOMIZING NOZZLE INCORPORATED IN THE VALVE CONE
A typical example is an integrated spray water injection system. Spray water is transported through the
hollow valve stem, and injected at the nozzle outlet. In addition, atomizing steam is utilized,
extracting the steam downstream of the valve seat portion. The steam is expanded in a Laval ring nozzle.
This unique design provides excellent water evaporation. The design eliminates the need for a separate
steam atomizing valve.
ADVANTAGES :
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Rapid absorption of water particles due to high mechanical energy of atomizing steam.
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Temperature control as close as 3 - 4 deg.C. above saturation.
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Short straight outlet line required, even at low steam velocities.
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High turndown ratio of 25:1
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No additional piping for atomizing steam.
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Eliminates the need for a separate steam atomizing valve.
BYPASS VALVE WITH ATOMIZING NOZZLE INCORPORATED IN THE PRESSURE REDUCING STAGE AT THE VALVE OUTLET :
This design incorporates the atomizing nozzle in the Pressure Reducing Stage (Silencer) at the valve outlet.
Here, the Laval nozzle is not a straight type but a ring nozzle which creates a circular laval jet. The spray water
is catered through passages in the pressure reducing plate and injected into the laval ring nozzle. This
efficient design eliminates the need for an atomizing steam valve and steam atomizing lines.
ADVANTAGES :
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High turndown ratio of 25:1
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Excellent Temperature control as close as 3 - 4 deg.C. above saturation.
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Short straight outlet line required, even at low steam velocities.
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No additional piping for atomizing steam.
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Eliminates separate steam atomizing valve.
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Instant absorption of water particles owing to high mechanical energy of atomizing steam.
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