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USER INSTRUCTIONS |
Automax Valve Automation Systems |
Installation |
Apex 8000 High-Performance Positioner |
Operation |
AXENIM0130-06 11/10 |
Maintenance |
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Apex 8000 High-Performance Positioner AXENIM0130-06 11/10
Principles of Operation
This bulletin is designed to assist in installing, calibrating, troubleshooting and performing maintenance as required for the APEX 8000 Series high-performance positioner.
Product users and maintenance personnel should thoroughly read and strictly follow the instructions contained in this bulletin prior to operating the positioner. Any questions concerning this product should be directed to a Flowserve representative
To avoid possible injury to personnel or damage to valve parts, WARNING and CAUTION notes must be strictly followed. Modifying this product, substituting non-factory parts or using maintenance procedures other than outlined could drastically affect performance and be hazardous to personnel and equipment.
The APEX 8000 high-performance positioner is a two-stage device and is designed for use in control loops where fast response is required. The APEX 8000 positioner is designed to be modular and use the P/P module for 3-15 psi input signal or the NT 3000 Series Transducer Module for 4-20 mA input signal.
The APEX 8000 high-performance positioner is designed as a four-way device, but can easily be converted to a three-way device by plugging one of the output ports.
NOTE: The APEX 8000 high-performance positioner must use the I/P NT 3000 Transducer. The I/P 2000 Transducer is not acceptable for use with the APEX 8000 Series Positioner.
The APEX 8000 positioner can handle supply pressures up to 150 psi; thus, a supply regulator is usually not required. However, a five micron air filter is required for pneumatic positioners and a coalescing filter is required for I/P positioners.
NOTE: The air supply should conform to ISA Standard S7.3 (a dew point at least 18° F / -8° C below ambient temperature, particle size below 5 microns, oil content not to exceed one part per million).
The APEX 8000 Series positioner features an adjustable gain of 400-1100:1. The medium gain setting is standard for smaller actuators, while the high gain setting is used on larger actuators (refer to ‘Gain Adjustment Procedure’ section for further details.)
Operation
The positioner schematic (Figure 1) shows an APEX 8000 Series positioner connected for double-acting service on a rotary rack-and-pinion actuator. Tension on the feedback spring provides feedback to the positioner, which varies as the stem position changes. The spring-loading force is applied through the feed-back linkage and cam to the positioner’s input capsule.
Instrument signal pressure is applied between the diaphragms in the input capsule. Therefore, the input capsule serves as a force-balance member, matching the valve stem position (as measured by tension on the feedback spring) to the instrument signal.
When the opposing forces balance exactly, the system will be in equilibrium and the stem will be in the exact position called for by the instrument signal. If the opposing forces are not in balance, the input capsule will move up or down and, by means of the pilot-valves, will change the output pressures, moving the stem until the tension on the feedback spring exactly opposes the instrument signal pressure.
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Apex 8000 High-Performance Positioner AXENIM0130-06 11/10
Balance Adjustment
Supply Seat
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Feedback Spring |
Zero Adjustment |
Upper Pilot |
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Range Adjustment |
Poppet |
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Screws |
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Exhaust Seat |
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Port No. 1 |
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Cam |
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Restriction |
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Supply |
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Pilot Valve |
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Feedback |
Capsule |
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(Shaft) |
Exhaust Seat |
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Instrument Signal |
Port No. 2 |
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Detecting |
Upper Diaphragm |
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Nozzle |
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Lower Pilot |
Flapper |
Lower Diaphragm |
Poppet |
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Input Capsule |
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Supply Seat
Piston Cylinder |
Figure 1: Apex 8000 Positioner Schematic for Air-to-Open
The sequence of operation is as follows: An increase in instrument signal pressure forces the input capsule downward. Displacement of the capsule in turn moves the flapper away from the detecting nozzle. This allows a larger flow rate through the nozzle, decreasing the pressure exerted on the top of the pilot valve capsule.
Supply air biases the pilot-valve in an upward direction. As the capsule moves up, it will close the exhaust seat of the upper pilot poppet and open the supply seat, which applies increased air pressure to the bottom cylinder port. At the same time, the pilot-valve capsule will open the exhaust seat for the lower pilot poppet; thus, decreasing pressure to the top cylinder port.
This difference in pressure will drive the piston outward, rotate the pinion and stretch the feedback spring until the spring tension exactly opposes the force resulting from the instrument signal pressure. At this point, the flapper will be moved toward the detecting nozzle to restore the pressure above the pilot-valve capsule to its equilibrium value. As a force-balanced condition is approached, the pilot-valve capsule will be forced back to a neutral position where the pilots are neither supplying air to, nor exhausting air from, their respective sides of the piston.
A decrease in instrument signal pressure reverses the described actions and cause a proportional inward movement of actuator pistons and a reversal in pinion direction.
Figure 2: Positioner Mounting with NAMUR Shaft
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Apex 8000 High-Performance Positioner AXENIM0130-06 11/10
Installation of APEX 8000 Series Positioner on Actuators
The APEX 8000 can be installed on most sizes of rotary and linear actuators. Actuators can be either double acting or spring return. Cams can be used for direct acting or reverse acting directions. These instructions apply to rotary actuators only. For linear actuator mounting instructions, consult the factory.
NOTE: For retrofitting to an actuator equipped with an Apex positioner, the same bracket and bolting may be used.
NOTE: NAMUR mounting is available with the APEX 8000 positioner. When retrofitting the APEX 8000 positioner to an actuator equipped with another positioner, remove the existing positioner, tubing and associated bolting. See tubing instructions in Connecting APEX 8000 Positioner Ports section.
Mounting Instructions for APEX 8000 with NAMUR Shaft Connection
1.Mount the bracket to the actuator. Finger tighten the bracket bolting.
2.If required, install a coupler on the actuator shaft. Make sure the shaft and coupler are centered. See Figure 2.
3.Verify the orientation of the actuator and coupler flats match the positioner flats on the end of the shaft. Loosen the cam if necessary. (See “Cam Installations” instructions.)
4.Install the positioner onto the bracket. Make sure positioner shaft and coupler are engaged and centered. Finger tighten positioner bolts.
5.WARNING: Once the positioner is mounted on the bracket, make certain that the vent on the bottom of the positioner is not covered by the bracket. If it is, remove the positioner from bracket and drill a 1/2” hole in the bracket to allow venting of the positioner. Blocking the vent can cause pressurization of the housing and cause positioner failure.
6.Proceed to “Connecting APEX 8000 Positioner Ports.”
Connecting APEX 8000 Positioner Ports:
1.For double acting actuators, connect positioner ports 1 and 2 to the actuator. Port 1 is always connected to the actuator port used to drive the actuator away from its start or fail position (the factory cam setting is full clockwise at minimum input signal).
NOTE: For single acting, spring return actuators, plug output port
2.Connect supply air to the port marked “SUPPLY.”
3.Connect air (for pressure inputs) or instrument tubing or wiring (for 4-20 mA inputs). For current inputs, the terminal is marked (+) and (-) inside the I/P module. The I/P is factory calibrated and should not require adjustment. If adjustments are necessary, see “Calibrating I/P Module Zero and Span Settings” section. Caution: Signal air pressure higher than 30 psi may damage the module gauge and instrument signal capsule; a 3-15 psi instrument signal is recommended on the pneumatic module.
4.Stroke actuator/valve two or three times to align positioner, coupler and actuator. With 50% input (actuator/valve at 45 degrees), tighten all mounting bolts. Stroke actuator/valve again to verify there is no misalignment throughout the stroke.
5.Calibrate valve and adjust cam if necessary. (See “Cam Installation” and “Positioner Calibration” instructions.)
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Apex 8000 High-Performance Positioner AXENIM0130-06 11/10
Figure 6: Alignment for Cams
Cam Removal
Disconnect cam return spring. With a wrench carefully placed on the output shaft (if necessary), loosen and remove the jam nut. Remove pressure from the span arm by pushing it away from the cam. Remove the cam.
Cam Installation
1.Make sure shaft is properly aligned with coupler or actuator.
2.Push span arm away from shaft to avoid pressure on the cam.
3.Place cam over the shaft with the appropriate characteristic facing up and closest to the span arm roller. “D” represents direct-acting and “R” represents reverse acting.
4.Make sure the round mark on the left hand side of the characteristic curve is lined up with the span arm roller bearing. See Figure 3.
5.Tighten jam nut making sure cam does not rotate. Use a flat screwdriver to prevent cam rotation and shaft flats to prevent shaft rotation (if necessary).
6.Connect supply pressure to port marked ‘Supply ‘stroke actuator/valve two or three times to align position with actuator. With a 50 percent input signal, tighten all mounting bolts. Stroke actuator to verify proper alignment.
Position Calibration
Introduction
APEX 8000 positioners are calibrated at the factory; however, due to shipping and handling, it may be necessary to check the calibration before operating the valve. The APEX 8000 positioner can be calibrated to a range of 3-15; two-way split range, 3-9, or 9-15; and three-way split ranging, 3-7, 7-11, 11-15 psi using the standard feedback spring.
WARNING: When stroking the actuator during calibration, keep hands, hair and clothing away from moving parts. Failure to do so may cause serious personal injury.
Note: Positioners and I/Ps are calibrated at the factory. Use mechanical adjustments in positioner for calibration. Zero and span on the I/P should not be used to calibrate the valve.
For calibration, refer to Figure 4 and proceed as follows:
1.For 3-15 or 3-9 psi range, loosen by hand the zero adjustment locking knob and adjust the zero adjustment knob until the valve begins to stroke with more than 3 psi signal (for 9-15 psi range adjust to 9 psi).
2.Loosen the span adjustment locking screw no more than 1/8 turn.
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