Discover our capabilities - watch this short video!

73N-B Positioner, Valve normally closed

73N-B Built-in Valve Positioner Normally Closed

Series 73 Built-in Pneumatic Valve Positioner Siemens Model 73N-B, Normally Closed Moore Positioner, 3-15 PSI. Includes positioner, gasket, screws, washers. A Built-in Valve Positioner which mounts directly on valves topworks, capable of utilizing full force of its air supply to drive piston or diaphragm, in a pneumatic actuator, to position called for by control instrument.

More details

10 quantities

Siemens Model # 73N-B is a Normally Closed Moore-Positioner, 3-15 PSI

Includes positioner, gasket, screws, washers

*** Note:  Spring & adapter for valve are not included.  Please see separate kit.  Springs/Adapters vary on manufacturer/model of the valve and size.  This standard moore positioner is the universal part.  

Model 73N-B is a bottom loading, built-in Valve Positioner which is mounted directly on the topworks of a valve.

Type of Application: bottom-loading, direct-acting, with tom air-cushion loading

Pneumatic Valve Positioners

73 Built-in Pneumatic Valve Positioner

Series 73 Built-In Pneumatic Valve Positioners

This line of compact pneumatic valve positioner instruments incorporates a single-axis, force-balance principle of operation to ensure accurate and stable control valve positioning.  In all cases, including bottom-loading applications, a Model 73 Built-In Pneumatic Valve Positioner is mounted directly on the topwork of the valve, with no external levers or other exposed mechanisms.

By selecting the appropriate range spring from the wide selection, almost any combination of valve stroke (from 1/4" to 4") and instrument span (from 2 to 24 psi) can be obtained.

  • Single-axis, force-balance principle of operation, ensures accurate and stable positioning

  • Feedback circuits direct the actuator's position, ensuring adherence to the control instrument signal

  • Range spring capability accomodates a wide variety of valve strokes and instrument spans


  • Input Range: 3-15psig
  • Valve Travel: 1/4"min. 4" max.
  • Ambient Temperature Limits: -40F to +180F (-40C to +82C)
  • Supply Pressure: 3psi above required actuator pressure (minimum), 100psig maximum
  • Air Consumption: (in balance condition with 20 psig supply and 9 psig dead-ended output) 0.6 scfm
  • Overrange Limit: 150 psig to any connection
  • Response Level: (output sensitivity to input pressure changes) 0.25% of input span

Mounting Dimensions

The topworks of the valve must have six, 1/4-20 x 9/16" deep (min.) blind tapped, equally spaced holes for mounting positioner.

Spring Selection

1. Find the valve stroke nearest the desired valve stroke.
2. Find the instrument input pressure span nearest the desired instrument input pressure span.
3. Select the proper range spring at the intersection of the valve stroke and the instrument input pressure span columns.

  • Actuator : NC normally closed
  • Item : Control