1. What are the benefits of Oscillator Load Pull?
2. How does the measurement work?
3. What makes Phase Dynamics different from other technologies?
4. What does Factory Calibration entail?
5. How is emulsion phase determined?
6. What can the user check on the Measurement Section?
7. What are the considerations in mounting and use?

 

1. What are the benefits of Oscillator Load-Pull?

Oscillator load-pull offers the benefits of measuring range, accuracy, repeatability, and resolution.  The oscillator is directly coupled to the materials in flow.  The range of frequency pull is designed to correspond to the range of measurement for the application.  As a result, the method produces 100 to 1,000 times improvement in measurement resolution over conventional microwave measurement techniques.

In addition, load-pull provides an instantaneous response in frequency to a respective change in material properties making it an excellent technology for real-time measurement.

Oscillator load-pull provides system simplicity.  It can be thought of as the signal source, the transmitter, and receiver simultaneously.  The required circuitry is therefore minimized resulting in fewer variables to compensate for.  Naturally, less circuitry translates to an increased in system reliability.  A simpler system provides an added benefit of faster troubleshooting in the event of a fault.

 

2. How does the measurement work?

A radio frequency oscillator is coupled to a transmission line system immersed within the measurement section fluids.  The fluids changing water percentage are the load-pull effects measured by a frequency change.  Because the electrical characteristics of water and oil are significantly different, the frequency of oscillation is different for each material.  As the material mix changes, so does the frequency of oscillation.  Full factory calibration thereby characterizes each Analyzer based on known percentage of water for maximum accuracy.

 

3. What makes Phase Dynamics different from other technologies?

The technology enables the tailoring of oscillator frequency range to measurement range.  It offers the maximization of measurement accuracy for each range of Analyzer produced.  From low range to full range, Phase Dynamics’ achieves 100 to 1,000 times the resolution of other technologies.  And, this is achieved with a technology that responds in real-time to the changing process.  The frequency of oscillation is a direct measure of the material composition in the measurement section.

 

4. What does Factory Calibration entail?

A sophisticated ensemble of factory test equipment comprises the calibration fluid loops that each Analyzer is characterized with prior to shipment.  For oil phase calibration, the loop is filled with oil of known properties and brought to temperature and pressure.  The routine begins with 100% oil circulating through the loop.  Systematically, water is slowly injected into the circulating oil at a controlled rate.  The frequency of oscillation, temperature and the forward and reflected power are characterized as a function of known Water-Cut.

Factory calibration of water phase begins with the loop loaded with 100% water of known salinity.  Temperature and pressure are then set.  With 100% circulating water at salinity and temperature the water calibration commences.  Systematically, oil is slowly injected into the circulating water at a controlled rate.  The frequency of oscillation, temperature, forward and reflected power are characterized for these conditions.  The water calibration continues for each salinity level with each new load beginning with 100% water at salinity.  Water calibration is a time consuming process, but considering the properties of water are highly determined by the salinity level, this extensive method produces the highest accuracy equipment.  
    
When the characterization process is completed for the Analyzer under test, the data set is transformed into a set of operating coefficients that are specific to the Analyzer.  Each Analyzer is unique in the sense that the Electronics Section and the Measurement Section are paired with the Electronics Section containing the coefficients for the Measurement Section.

 

5. How is emulsion phase determined?

In addition to oscillator frequency, the forward and reflected power is detected in the Measurement Section.  The electrical properties of oil phase are distinct from water phase.  Oil phase is insulating while water phase is conductive.  The simple combination of oscillator frequency considered against reflected power indicates emulsion phase.  Phase Dynamics determines emulsion phase continuously as materials flow through the Measurement Section.

 

6. What can the user check on the Measurement Section?

The only items that can be checked on the measurement section are the tightness of the oscillator housing, the RF front connector, and the RTD temperature probe connections. The oscillator housing has brackets on both sides to prevent vibration from loosening the RF Connector. The Measurement Section has the serial number on the end metal plug and the oscillator has a separate and different serial number on the end of its housing. Please use the serial number on the pipe section end when referring to the unit in correspondence, by fax, or in a service call.

The microwave electronics is a sealed box in order to prevent moisture from the air from getting inside. The circuitry is surface mount components because of the high frequencies involved and therefore, is not user serviceable. The measurement section and the oscillator are calibrated together and are considered a single unit. A unique set of equations are created for each unit with the calibration curves generated at the factory. If the measurement section (and electronics) has some technical problem, the main electronics can be used with another section by downloading and uploading the new calibration into the system electronics.

In addition to the electronics, a 100 ohm RTD platinum temperature probe is placed into the fluids just below the flange. This is connected to the electronics through a terminal block. The Swage Lock fittings are packed with sealant. The entire RTD and Swage system is typically replaced as a unit. If the RTD is shorted a 100 ohm resistor can be placed between P2 and P3 with jumpers between P+ and P2, and another between P3 and P4 to obtain temperature while the assembly is obtained and replaced. A suitable value may be used to obtain a close to fluid temperature reading to maintain temperature compensation. Installing a temporary resistor also verifies that the analog input board is operating correctly.

 

7. What are the considerations in mounting and use?


a) Flow Rates and Mounting of the Measurement Section

The orientation does not matter if the flow rate is above approximately 2 feet/second. This assures a homogeneous mixture in the measurement section. The maximum flow rate recommended is 14 feet/second.

If the flow rate is less than 2 feet/second, the recommended orientation of the Measurement Section is vertical with liquid flowing upward from the bottom to the top of the Measurement Section.  The Measurement Section should not be placed at the highest or lowest elevation in the line.  If placed low, a water-trap may result, if high a gas-trap may result.

For the High Range and Full Range Analyzers, the preferred direction of fluid flow is toward the electronics end of the Measurement Section.

If there is gas present, the preferred orientation is with the electronics end of the Measurement Section down and the flow from the bottom to the top. This assures that the free gas is removed from the section instead of accumulating it at one end. 

If the section is mounted horizontally and the flow rate is low sand may also accumulate in the section.

Additional installation issues are covered in the Installation and Instruction Manuals and illustrated within the installation video.


b) High Temperature Units

For high temperature (>100º C fluid temperature) operation, the electronics should be mounted football down due to the necessity of keeping the electronics portion below 120º F ambient. Otherwise, the heat rises and prevents the aluminum explosion proof box from radiating the heat to the ambient air. The electronics includes a very small built in heater to keep the electronics, which are temperature sensitive, at a temperature of 160º F. As the enclosure temperature (around the electronics) gets above approximately 120º F, the heater starts to regulate less. Above 140º F, the heater must almost shut down causing greater temperature changes at the circuit and therefore, there is a greater error in the measurement. There are several versions of the Phase Dynamics measurement sections for various temperature ranges.

c) Electrical Considerations

Cables and Grounding: Included with each system are a system cable and a green grounding wire. The system cable must be pulled from the measurement section end back to the main electronics due to the military type connector on one end. The green ground wire is to meet CSA requirements and also to assure a good earth ground is obtained between the measurement section and the electronics. This prevents ground loops from being carried in the system cable's shields. In all cases, the AC Input board should have an earth ground wire connected. In addition to the safety aspects, this assures a solid instrument ground.

d.) Flow Meter Input Connections

Pulsed flow inputs need to be at least 0.030 Volts and a maximum of 15 Volts. A magnetic pickup can be directly tied in without a preamp if the cables are run in conduit and are not excessive in length. A solid ground connection must be made at the flow meter and at the Phase Dynamics' electronics in order to assure extra pulses are not obtained. Current flow inputs can be used in conjunction with other devices in the current loop only if the Phase Dynamics is the last instrument on the loop's path nearest to the ground leg.