Flowserve Desuperheaters User Manual
USER INSTRUCTIONS
Desuperheaters
FCD VLENIM0115-00 – 09/11
Installation
Operation
Maintenance
Experience In Motion
2
Desuperheaters FCD VLENIM0115-00 – 09/11
This bulletin contains descriptions of the MaxCool MCX, VaporCool, and VaporCool MicroNozzle
desuperheaters along with their basic principles of operation and characteristics. Also included are
instructions for installing, operating and maintaining these desuperheaters. The information contained
herein is intended to be a general guide for steam desuperheating applications.
DESCRIPTION AND PRINCIPLES OF OPERATION
Desuperheaters are used to reduce steam temperature by injecting atomized water into the superheated
steam flow. Desuperheater nozzles can be lance mounted as shown in Figure 1 or manifold mounted
as shown in Figures 2 and 3. Lance mounted desuperheaters can be equipped with MaxCool MCX,
VaporCool, or VaporCool MicroNozzle nozzles. Manifold mounted desuperheaters can be equipped with
MaxCool MCX or VaporCool MicroNozzle nozzles.
Figure 1: Lance Mounted MaxCool MCX Desuperheater
Cooling Water
Flange
Mounting Flange
Lance
Lance/Nozzle
Pipe Connection
MaxCool MCX
Nozzle Assembly
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3
Figure 2: Manifold Mounted MaxCool MCX Desuperheater
Manifold Connector
Manifold Pipe
Desuperheaters FCD VLENIM0115-00– 09/11
Steam Pipe
Manifold Tee
Connecting Pipe
Steam Pipe Wall
MaxCool MCX
Nozzle Assembly
(See Figure 4)
Figure 3: Nozzle Housing Assembly
Nozzle Housing
End Flange
Nozzle Housing
Assembly
(See Figure 3)
Nozzle Seat
Retainer
Nozzle Housing
Cap Flange
Cap Flange
Bolting
Tack Weld
Weld
Gaskets
4
Desuperheaters FCD VLENIM0115-00 – 09/11
MaxCool MCX Nozzle
The MaxCool MCX nozzle is a variable area hollow cone nozzle that produces a fine droplet spray mist.
Figure 4 shows a cross-section of the nozzle assembly with the parts identified. The maximum rangeability for the MaxCool MCX nozzle is approximately 20:1.
The plug is assembled through the seat and is biased against the seat with a spring. The spring is held
in place with a retainer that is screwed onto the plug. The retainer limits the stroke of the plug to ensure
proper water atomization. A castle nut with an expansion pin or a bent washer locks the assembly
together.
The geometry of the nozzle assembly is optimized to provide efficient cooling by minimizing water
droplet size. When the Δp between the cooling water and the steam is sufficient to overcome the preload
of the spring, the plug moves away from the seat and cooling water circulates through the nozzle openings. As the water moves down the conical shaped plug and exits past the sharp edges of the narrow
plug opening, the cooling water is atomized into a fine spray mist.
Figure 4: MaxCool MCX Nozzle Assembly Cross-Section
Mounting
Thread
Expansion Pin
Castle Nut
Retainer
Spring
Stroke Length
Nozzle Openings
Seat
Plug
Nozzle Diameter
5
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Desuperheaters FCD VLENIM0115-00– 09/11
Table 1 shows the available MaxCool MCX desuperheater nozzle model numbers with their CV’s, outer
diameters, mounting thread sizes, and weights.
Table 1: MaxCool MCX Nozzle Data
Model
Number
MCX 025 0.25 0.24 0.81 0.63-18UNF 0.07
MCX 050 0.50 0.90 0.94 0.75-16UNF 0.13
MCX 075 0.75 1.80 1.38 1.00-12UNF 0.36
MCX 100 1.00 3.10 1.63 1.25-12UN 0.62
MCX 125 1.25 4.50 2.00 1.50-12UN 1.1
MCX 150 1.50 6.50 2.25 1.75-12UN 1.6
MCX 175 1.75 8.10 2.56 2.00-12UN 2.5
MCX 200 2.00 10.50 2.81 2.25-12UN 3.3
Table 2 shows the materials of construction for the MaxCool MCX nozzle assembly:
Table 2: MaxCool MCX Materials of Construction
Components of
Nozzle Assembly
Plug 416 SS HT
Seat 416 SS
Retainer 416 SS
Spring Inconel X-750
Castle Nut Stainless Steel
Expansion Pin Stainless Steel
Nozzle
Diameter (in)
CV
Material of
Construction
Outer
Diameter (in)
Mounting
Thread Size
Nozzle
Assembly
Weight (Lb)
6
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