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Siemens
Energy & Automation
MODEL 73N BUILT-IN VALVE POSITIONER
The Model 73N is a Built-in Valve Positioner which is mounted directly on the topworks of a valve. It is capable of
utilizing the full force of its air supply to drive the piston or diaphragm, in a pneumatic actuator, to a position called
for by the control instrument. The positioner incorporates a single-axis force-balance principle of operation to insure
accurate and stable positioning of a control valve.
MODEL DESIGNATION
Basic Model Number
Input Span – psig
Special Feaures
F — Fast response
R — Reverse acting
E — Tapped Exhaust
USM — U.S. Electrical Motors Type
Fast Response: The fast response positioner is used on actuators with large volume topworks requiring a fast
response action. Due to increased pilot plunger travel and larger ports in the fast response positioner, greater filling
and exhausting capacities result. This permits a quicker response to a change in control conditions, plus increased
speed of valve operation.
Tapped Exhaust: The Model 73N Positioner can be ordered with a tapped exhaust port. This feature permits piping
of the pilot exhaust to a safe atmosphere on applications where noxious gases are used as a control medium instead
of air.
USM: On actuators with small topworks and a low volume, a special hi-response positioner may be used. This
positioner is denoted by the letters USM in the model number. There is no bleed on this model due to the low
volume. A special valve plunger is used to ensure fast response for close control.
GENERAL SPECIFICATIONS
Instrument Input Pressure Range...................3-15, 3-9, 9-15, and 3-27 psig
Supply Pressure
Minimum................................................3 psi above required actuator pressure
Maximum ...............................................100 psi
Air Consumption ...........................................0.25 SCFM (in balance condition with 20 psi supply and 9 psi dead
Valve Travel
Minimum................................................1/4"
Maximum ...............................................4"
Ambient Temperature Limits ........................-40°C to +82°C (-40°F to +180°F)
INSTALLATION AND SERVICE INSTRUCTION
73N
12
F
ended output)
SD73
Rev 13
September 2008
Supersedes Rev 12
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Table of Contents
Related Manuals for Siemens 73N12F
Summary of Contents for Siemens 73N12F
- Page 1 Siemens INSTALLATION AND SERVICE INSTRUCTION Energy & Automation SD73 Rev 13 September 2008 Supersedes Rev 12 MODEL 73N BUILT-IN VALVE POSITIONER The Model 73N is a Built-in Valve Positioner which is mounted directly on the topworks of a valve. It is capable of utilizing the full force of its air supply to drive the piston or diaphragm, in a pneumatic actuator, to a position called for by the control instrument.
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Page 2: Installation
SD73 INSTALLATION Refer to Figure 1 for mounting dimensions and connections. A centering washer (customer provided) which fits the I.D. of the range spring should be used. This acts as a spring seat and keeps the spring from shifting. Mounting hardware is included with the positioner in a plastic bag numbered 10448-88. It contains (6) mounting screws and washers, (1) range spring seat and (1) gasket. - Page 3 SD73 There are many types of synthetic lubricants. Some may not be compatible with the materials used in the construction of the positioner. Wetting of these materials by such an oil mist or oil vapor, etc., may cause them to deteriorate.
- Page 4 SD73 Dew Point — Dew point at line pressure should be at least 10°C (18°F) below the minimum temperature to which any part of the instrument air system is exposed at any season of the year. Under no circumstances should the dew point at line pressure exceed 2°C (35.6°F).
- Page 5 Notes: 1) The maximum zero pressure for the Model 73N12F is 9 psig when the 12395 series range spring is used. 2) The maximum zero pressure for the Model 73N24F is 15 psig for instrument pressure spans of 16 psi or greater and 28 psig when used for spans of 12 psi or less.
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Page 6: Maintenance General
SD73 MAINTENANCE GENERAL Clean, dry, oil-free instrument air will reduce most problems associated with pneumatic instruments. Refer to INSTRUMENT AIR REQUIREMENTS. If these requirements are observed, no routine maintenance is recommended. Cleaning the plunger is to only maintenance which may be required on an occasional basis. - Page 7 SD73 Figure 4 Schematic – Direct Acting Figure 5 Schematic – Reverse Acting...
- Page 8 Siemens public Internet site (see the table) has current revisions of technical literature, in Portable Document Format, for downloading. • To send an instrument to Siemens for warranty or non-warranty service, call Repair Service and request a Return Material Authorization (RMA). IMPORTANT An instrument must be thoroughly cleaned (decontaminated) to remove any process materials, hazardous materials, or blood-borne pathogens prior to return for repair.
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Page 9: Warranty
Siemens Energy & Automation, Inc. assumes no liability for errors or omissions in this document or for the application and use of information in this document. The information herein is subject to change without notice. -
Page 10: Parts List
3/91 Supersedes 8/88 IMPORTANT Service Parts Kits are available for servicing the instrument. Contact Siemens for available kits; refer to the Product Support section of this instruction. Some parts in this Parts List may not be available for separate purchase. - Page 11 3/91 Supersedes 5/86 IMPORTANT Service Parts Kits are available for servicing the instrument. Contact Siemens for available kits; refer to the Product Support section of this instruction. Some parts in this Parts List may not be available for separate purchase.