Valve Positioners Series 73 Built-In Valve Positioner Introduction Features & Benefits 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 accommodates a wide variety of valve strokes and instrument spans Description The Series 73 Built-in Valve Positioners use the full force of 3 their air supply to drive and maintain the piston or diaphragm in a pneumatic actuator to position a valve to what is required by a control instrument, regardless of the presence of forces that change valve position. This line of compact 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 Valve Positioner is mounted directly on the topwork of the valve, with no external levers or other exposed mechanisms. Each positioner receives a signal from a control instrument, and using an air supply as high as 100 psig, the positioner strokes the valve actuator to the required position. Air Consumption Like all valve positioners, the Model 73 Built-In Valve (In balance condition with 20 psig supply and 9 psig dead- Positioners have feedback circuits designed to measure the ended output) position of the actuator's piston or diaphragm. The positioner • 73N_F: 0.25 scfm then supplies or exhausts air to bring the actuator within the • 73N_B: 0.6 scfm required range for its corresponding control instrument. Overrange Limit The position of the piston or diaphragm in the valve actuator 150 psig to any connection is sensed by the amount of compressive force exerted by a range spring on the valve positioner's diaphragm assembly. Response Level By selecting the appropriate range spring from the wide (output sensitivity to input pressure changes) selection available almost any combination of valve stroke • 73N_F: 0.1% of input span (from 1/4" to 4") and instrument span (from 2 to 24 psi) can • 73N_B: 0.25% of input span be obtained. Functional Mechanical Materials of Construction Specifications ® Aluminum, brass, stainless steel, Neoprene , and/or Buna-N Functional Specifications Input Range 3-15, 3-9, 9-15, 6-30, 3-27 psig Model Selection Valve Travel Model Type of Application Minimum: 1/4" 73N12F Top-loading, direct-acting, input spans Maximum: 4" of 2 to 12 psi Supply Pressure 73N24F Top-loading, direct-acting, input spans Minimum: 3 psi above required actuator pressure over 12 to 24 psi Maximum: 100 psig 73N-FR Top-loading, reverse-acting 73N-B Bottom-loading, direct-acting 73N-B1 Bottom on actuators w/actuator range spring 3.7 Valve Positioners Series 73 Built-In Valve Positioner Technical data Spring Table Instrument Input Pressure Span (PSI) 4 568 10 12 16 20 24 Valve - Item No. of Range Spring Series Stroke 12395 Series ±5% Stroke Range Tolerance Inches Example: 12395-1212 1/4 1212 1012 812 612 512 412 624 524 424 5/16 1612 1212 1012 712 612 512 824 624 524 3/8 1812 1412 1212 1012 712 612 1024 724 624 7/16 2012 1812 1412 1012 812 712 1024 824 724 3 1/2 2412 2012 1612 1212 1012 812 1224 1024 824 9/16 2812 2012 1812 1412 1012 1012 1424 1024 5/8 3212 2412 2012 1612 1212 1012 1624 1224 1024 3/4 3612 2812 2412 1812 1412 1212 1464 1224 7/8 4412 3612 2812 2012 1812 1412 2024 1624 1424 1 4812 4012 3212 2412 2012 1612 2424 2024 1624 1-1/8 5612 4412 3612 2812 2012 1812 2024 1-1/4 6412 4812 4012 3212 2412 2012 2824 2424 2024 1) The maximum zero pressure for 1-1/2 6412* 4812 3612 2812 2412 4024 2824 2424 Model 73N12F is 9 psig when the 12395 series range spring is used. 1-5/8 6412* 4812 4012 3212 2612 4024 3224 2) The maximum zero pressure for 1-3/4 6412* 5612 4412 3612 2812 4024 3224 2824 Model 73N24F is 15 psig for instrument pressure spans of 16 2 6412* 4812 4012 3212 4824 4024 3224 psi or greater, and 28 psig when 2-1/4 5612 4412 3612 4024 used for spans of 12 psi or less. 2-1/2 6412* 4812 4012 4824 4024 3) The maximum instrument pressure for Model 73N-FR is 2-3/4 6412* 4812 4412 4824 4824 15 psig for instrument pressure spans of 12 psi or less, and 27 psi 3 6412* 4812 4824 for spans of 16 psi or greater. 3-1/2 5612 4 6412* Mounting Dimensions 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. 3.8