Instruction Manual
D104734X012
Fisher™ ATST Desuperheater
ATST Desuperheater
July 2022
Contents
Introduction 1.................................
Scope of Manual 1.............................
Description 1.................................
Educational Services 2.........................
Installation 3..................................
Maintenance 5.................................
Servicing 6...................................
Parts Ordering 8................................
Parts List 8....................................
Introduction
Scope of Manual
Figure 1. Fisher ATST Desuperheater
X1892
This instruction manual includes installation, maintenance, and operation information for the Fisher ATST
desuperheater.
Do not install, operate, or maintain an ATST desuperheater without being fully trained and qualified in
valve, actuator, and accessory installation, operation, and maintenance. To avoid personal injury or
property damage, it is important to carefully read, understand, and follow all the contents of this manual,
including all safety cautions and warnings. If you have any questions about these instructions, contact your
Emerson sales office
before proceeding.
Description
Water atomization and vaporization are key elements in any steam conditioning application. The ATST design
incorporates a manifold of patented nozzles to inject atomizing steam and spraywater into process steam. These
specialized nozzles produce an optimized spray pattern over a wide operating range. These nozzles are strategically
placed to achieve optimal mixing and quick vaporization at all flowing conditions. Years of experience with other
steam atomized desuperheater designs went into the development of this construction. Extensive use of
computational analysis, in addition to field performance feedback, was used to validate spray system performance.
www.Fisher.com
ATST Desuperheater
July 2022
Table 1. Specifications
Instruction Manual
D104734X012
Connections
(1)(3)
Steam Line: NPS 8 through NPS 60
(DN 200 through 1500)
Spraywater: NPS 1 through 4 (DN 25 through 100)
Atomizing Steam: NPS 1 (DN 25)
Construction Materials
Desuperheater Body and Liner (if applicable):
J Carbon Steel, J 2-1/4 Cr-1 Mo J 9 Cr-1 Mo-V
J 9 Cr-2 W-V
Spray Nozzles:
Gaskets:
Bolting:
J R31233 Cobalt-Chrome Alloy
J N06600/Graphite
J SA193 Grade B7, J SA193 Grade B16,
(5)
J N07718
Connection Types
Steam Line (all sizes): JButtweld , JRaised Face
Flanges,
JRing Type Joint Flanges
Spraywater:
Face Flanges (all sizes),
JSocket Weld
sizes),
Atomizing Steam (all sizes):
JRing Type Joint Flanges
(1)(3)
JASME Buttweld (all sizes), JRaised
JRing Type Joint Flanges (all
JRaised Face Flanges,
Maximum Inlet Pressures
(1)
Consistent with applicable pressure-temperature
ratings per ASME B16.34
Maximum Unit Cv (for Spraywater Flow)
Contact your Emerson sales office
Spraywater Pressure Required
(2)
3.5 to 35 bar (50 to 500 psi) greater than steam line
pressure
(4)
(1)(3)
Atomizing Steam Pressure Required
Atomizing steam source pressure typically should be
at least 2 times the pressure of the steam to be
desuperheated
Pressure Class
Steam Line: According to the customer design
pressure and temperature
Spraywater and Atomizing Steam: ASME CL150 to
CL2500
1. Do not exceed the pressure or temperature limits in this manual, nor any applicable code or standard limitations.
2. A function of required turndown and equipment selection.
3. Offerings meet ASME standards. Consult your Emerson sales office for additional options.
4. Intermediate rating above CL2500 available upon request. PN ratings also available per pressure requirements of EN1092-1. Consult your Emerson sales office for additional information.
5. EN material options available upon request, consult your Emerson sales office for additional information.
Educational Services
Emerson Automation Solutions
Educational Services - Registration
Phone: 1-800-338-8158
E-mail: education@emerson.com
emerson.com/mytraining
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Instruction Manual
D104734X012
Figure 2. Typical Fisher ATST Installation
USPL
KEY:
DSPL = DOWNSTREAM STRAIGHT PIPE LENGTH
PI = PROPORTIONAL INTEGRAL CONTROLLER
PSL = PRESSURE SENSOR LENGTH
PT = PRESSURE TRANSMITTER
TE = TEMPERATURE SENSOR ELEMENT
TSL = TEMPERATURE SENSOR LENGTH
X0355A-1
USPL = UPSTREAM STRAIGHT PIPE LENGTH
ATST Desuperheater
July 2022
PI PT
TSL
PSL
DSPL
TE
Installation
WARNING
Always wear protective gloves, clothing, and eyewear when performing any installation operations to avoid personal
injury.
Personal injury or equipment damage caused by sudden release of pressure may result if the ATST desuperheater is
installed where service conditions could exceed the limits of the pressure rating noted on the nameplate. To avoid such
injury or damage, provide a relief valve for over pressure protection as required by government or accepted industry codes
and good engineering practices.
Check with your process or safety engineer for any additional measures that must be taken to protect against process
media.
If installing into an existing application, also refer to the WARNING at the beginning of the Maintenance section in this
instruction manual.
WARNING
When ordered, the desuperheater configuration and construction materials were selected to meet particular pressure,
temperature, pressure drop, and fluid conditions. Do not apply any other conditions to the desuperheater without first
contacting your Emerson sales office
1. Before installation, all piping upstream of the desuperheater must be cleaned so that no loose materials such as
welding slag, dirt or other foreign matter are left in the pipe. Use care to keep foreign matter out of the line
openings while preparing the desuperheater installation.
.
3
ATST Desuperheater
July 2022
Instruction Manual
D104734X012
WARNING
Do not lift the desuperheater by its cooler manifold piping. Personal injury or damage to equipment could occur if the
desuperheater is improperly lifted into place.
All lifting and rigging must be completed in accordance with federal/national/provincial, state and local regulations
and applicable lifting and rigging equipment standards. Only personnel trained in proper lifting and rigging practices
shall perform desuperheater assembly lifting, rigging and installation. Because each lift will be unique, the method of
lifting thedesuperheater assembly, the correct location for attaching and lifting the desuperheater assembly, and what
the desuperheater assembly will do when lifted shall be considered for each lift.
Lifting and rigging equipment used to lift, install or remove a desuperheater assembly or component must be
properly selected and sized for the weight and configuration of the desuperheater assembly or component being
lifted. The weight of the complete desuperheater assembly, including attached accessories, must be taken in
consideration for this purpose. The lifting and rigging equipment must be properly maintained and inspected for
damage before each use.
Lifting lugs or other lifting equipment attached to the desuperheater must never be used to lift or support the weight
of attached piping.
If the ATST is equipped with buttweld ends, the desuperheater body must be supported using a lifting sling or other
method that does not place a load or force onto the finished surface of the buttweld ends. The ATST does not have a stable
resting condition. The desuperheater inlet and outlet must be fully supported until fully welded (buttweld end
connections) or bolted (flanged end connections) into the piping.
2. Arrange lifting slings, or other lifting and rigging equipment appropriate for the desuperheater weight and
configuration
, around the main steam pipe to safely lift the ATST to the pipe opening.
WARNING
Do not expose the ATST to undue stresses by installing it in bent pipes or flanges. Personal injury and equipment damage
could result from flange sealing failure due to improper installation.
3. Flanged Connections—Lubricate the flange connection bolts with a high temperature thread lubricant. Install flange
gaskets and connection bolts per accepted practices and tighten securely.
4. Welded Connections—Welding procedures should be in accordance with the applicable codes and the base
materials. For preheat, welding electrodes, and postweld heat treatment, refer to the applicable codes and
practices applicable for the specific facility. Materials are specified on the customer specification sheet.
NOTICE
Depending on desuperheater body materials used, post weld heat treating may be required. If so, damage to internal parts
is possible. In general, if post weld heat treating is to be performed, all nozzles should be removed. Contact your Emerson
sales office for additional information.
5. Remove the spraywater control valve and flush the cooling water line until all debris is removed from the line prior
to connecting it to the ATST desuperheater. Use only clean sources of cooling water to reduce the possibility of
nozzle clogging. A strainer should be installed in the water line as close to the ATST desuperheater as possible. To
determine appropriate mesh size, refer to desuperheater sizing and specification document, or contact your
Emerson sales office. Review strainer manufacturer's pressure drop curves to determine appropriate strainer body
size. You may need to use a strainer that is larger than the water line size.
6. Remove the atomizing steam valve and flush the steam line until all debris is removed from the line prior to
connecting it to the ATST desuperheater.
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