Applying Precision Turbine Flow Meters

High precision turbine flow meters
Courtesy Cameron Measurement Systems

Precision turbine flow meters are specially designed to accommodate a broad range of precise fluid measurement applications. They accommodate greater flow rates with lower pressure drops than other meters in their class. Some have a self-flushing design for longer sustained accuracy. The turbine's high-frequency digital output is suitable for interfacing with an assortment of readout and recording equipment. Some turbine flow meters have a symmetrical bi-directional design that supports reverse flow applications without a reduction in accuracy or capacity.

Operating Principle

(The following is excerpted from Model 700 Series Turbine Flowmeter User Manual, from Cameron Measurement Systems....with some editing)

Fluid flows over a diffuser section and is accelerated onto a multi-blade hydro-dynamically balanced turbine rotor. The rotor speed is proportional to the volumetric flow rate. As the rotor turns, a reluctance type pickup coil (mounted on the meter) senses the passage of each blade tip and generates a sine wave output with a frequency that is directly proportional to the flow rate.

The rotor is the only moving part of the turbine flow meter. The small lightweight rotor hubs ensure fast response to process flow changes. The rotor is hydro-dynamically balanced during operation, eliminating the need for mechanical thrust leveling. This low-friction design improves metering linearity and reduces wear and maintenance.

A variable reluctance generating pickup coil contains a permanent magnet and a wire winding. In some cases, the rotor blade of the turbine meter is made of a ferritic stainless steel such as grade 430. The movement of the rotor blade in proximity to the magnetic field of the coil tip produces an AC type voltage pulse within the coil winding. An alternate arrangement finds the ferritic bars embedded in the rotor shroud, where they can interact with the pickup coil. Increasing the quantity of bars on the shroud to outnumber the rotor blades provides more pulses per unit volume (resolution). This feature can be valuable when proving large-capacity meters with a small-volume prover. Shielded wire cable conveys the output of the pickup coil to compatible electronic instruments to indicate flow rate, record, and/or totalize the volumetric flow. The coil itself does not require electrical power to operate.

The meter may be factory-fitted with multiple coils for redundancy, indication of flow direction or pulse train verification. The pickup coil type and magnetic strength vary with application requirements.

The turbine flow meters are calibrated in a horizontal position. Therefore, the best correlation of calibration occurs when the meter is operated in this plane. However, the meter will operate satisfactorily in any position.

System Pressure

The maximum and minimum system pressures must be considered when applying the turbine meter. To obtain proper response, a back pressure should be applied to the meter. This back pressure should be at least twice the pressure drop of the meter at maximum flow. For liquid meters, the back pressure should be twice the pressure drop of the meter at maximum flow, plus twice the fluid vapor pressure.

Summary

Turbine flow meters, with their simple, durable construction and wide operating range, may be the right choice for a number of applications. As with all instrumentation, there are a number of factors to consider when making a selection. Share your flow measurement challenges and requirements with instrumentation specialists, combining your process knowledge with their product application expertise to develop the most effective solutions.

Turbine Liquid Flow Meters from MSJacobs-Cali

Video Demonstration of Transit Time Difference Method of Flow Measurement

Portable Ultrasonic Flow Meter
Flexim

The measure of flow is a pervasive task in fluid process control. There are several differing technologies employed for measuring fluid flow, each with its own set of performance and application attributes that might make it the advantageous choice for a particular operation.

Ultrasonic flow measurement uses several methods for determining the average velocity of a fluid. One of those methods employs the difference in the transit times of ultrasonic pulses travelling with the flow direction and against the flow direction. The flow velocity of the media will offset the transit times between the flow and counterflow measurements. The measured difference in transit times can be used to determine average flow velocity and, with additional processing, mass flow.

Ultrasonic flow meters are accurate and provide repeatable results, making them suitable for custody transfer operations, as well as many other process control applications. Little maintenance is required and the units have no moving parts. Measurement instruments are available with in-line or clamp-on mounting, providing a high level of installation and application flexibility.

The short video below provides a clear explanation of how transit time difference measurement works. Share your flow measurement challenges and requirements with a product application expert, combining your process knowledge with their product expertise to develop effective solutions.

RTD or Thermocouple for Your Temperature Measurement Application?

Temperature Sensor Assembly
Wika

Proper temperature sensor selection is key to getting useful and accurate data for maintaining control of a process. There are two main types of temperature sensors employed for industrial applications, thermocouple and resistance temperature detector (RTD). Each has its own set of features that might make it an advantageous choice for a particular application.

Thermocouples consist of a junction formed with dissimilar conductors. The contact point of the conductors generates a small voltage that is related to the temperature of the junction. There are a number of metals used for the conductors, with different combinations used to produce an array of temperature ranges and accuracy. A defining characteristic of thermocouples is the need to use extension wire of the same type as the junction wires, in order to assure proper function and accuracy.
Here are some generalized thermocouple characteristics.

• Various conductor combinations can provide a wide range of operable temperatures (-200°C to +2300°C).
• Sensor accuracy can deteriorate over time.
• Sensors are comparatively less expensive than RTD.
• Stability of sensor output is not as good as RTD.
• Sensor response is fast due to low mass.
• Assemblies are generally rugged and not prone to damage from vibration and moderate mechanical shock.
• Sensor tip is the measuring point.
• Reference junction is required for correct measurement.
• No external power is required.
• Matching extension wire is needed.
• Sensor design allows for small diameter assemblies.

RTD sensors are comprised of very fine wire from a range of specialty types, coiled within a protective probe. Temperature measurement is accomplished by measuring the resistance in the coil. The resistance will correspond to a known temperature. Some generalized RTD attributes:

• Sensor provides good measurement accuracy, superior to thermocouple.
• Operating temperature range (-200° to +850°C) is less than that of thermocouple.
• Sensor exhibits long term stability.
• Response to process change can be slow.
• Excitation current source is required for operation.
• Copper extension wire can be used to connect sensor to instruments.
• Sensors can exhibit a degree of self-heating error.
• Resistance coil makes assemblies less rugged than thermocouples.
• Cost is comparatively higher

Each industrial process control application will present its own set of challenges regarding vibration, temperature range, required response time, accuracy, and more. Share your process temperature measurement requirements and challenges with a process control instrumentation specialist, combining your process knowledge with their product application expertise to develop the most effective solution.

Installing Heat Tape - Instructional Video

BriskHeat manufactures a broad range of heating equipment and componentry. Their heat tape is routinely applied across many applications involving heating of gases, liquids, and solids. The video included below provides simple and well illustrated guidance for selecting and properly installing heat tape to provide for safety and longevity.

Heat tape is flexible in its application, inexpensive, and easy to use. The video shows the three basic types, along with their application limitations and basic selection criteria. Instruction is provided on how to properly prepare the installation surface. The tools and materials needed for installation are also shown.

Share your process, pipe, and valve heating challenges with application specialists. Combining your process or application knowledge with their product expertise will produce a good match between product and application.

BriskHeat Joins the M.S. Jacobs Lineup

M.S. Jacobs is pleased to announce its new representation agreement with BriskHeat Corporation. The industrial heaters manufactured by BriskHeat complement many of the other quality products handled by M.S. Jacobs.

BriskHeat manufactures a broad line of heaters, insulators, and controls for almost every industrial application.

• Cloth Heating Jackets and Insulators
• Heating Tapes
• Heating Cable
• Laboratory Heaters and Equipment
• Etched Foil Heaters
• Silicone Rubber Heaters
• Drum Heaters
• Tote Tank / IBC Heaters
• Gas Cylinder Warmers
• Enclosure Heaters
• Hopper Heating Systems
• Personal Comfort Heating Solutions
• Hazardous-Area Heaters
• Plastic Bending Heaters
• Resistance Wire
• Temperature Controllers
• Temperature Controllers for Outdoor Use
• Insulators
• Heaters and Controls with Canadian Approvals
• Composite Curing Solutions

Share your industrial and process heating requirements with the product specialists at M.S. Jacobs & Associates. Combining your process expertise with their product knowledge will produce effective solutions.

Analynk Wireless For Process Control Connectivity

Analynk Wireless is an innovative designer and supplier of wireless instrumentation for the process control industry. Their instruments and equipment have been successfully implemented in numerous applications for temperature measurements, 4-20 mA bridges, discrete inputs/outputs, pulse inputs, lighting and pump controls. Analynk's products are used in both hazardous and non-hazardous locations. Watch the short video for a animated overview of Analynk products and capabilities.

Share your wireless connectivity challenges with product specialists. Combining your process knowledge with their expertise with produce effective solutions.

Gentherm GPT Provides Turnkey Remote Power

Thermoelectric Generators, part of  a remote power system

There are many industrial operations and processes that operate outside the confines of a factory building. Some even operate outside the confines of what most consider "civilization". Sometimes, if you need electric power, you have to generate your own.

Gentherm Global Power Technologies specializes in providing equipment and complete systems to produce electric power at remote sites. Their signature product line is the thermoelectric generator, or TEG. It uses a solid state thermopile and gas fired heaters to generate DC current. The technology is especially useful at sites where gas is naturally present. As a turnkey systems provider, Gentherm GPT will design complete systems, customized and configured for each particular installation. Here is an example of a fuel gas conditioning system provided for an offshore oil rig, designed specifically to address an issue at the site.

GPT's power generation products are well suited for a wide array of applications.

• Oil, gas, product, or water pipelines
• Well sites
• Offshore platforms
• Telecommunication sites
• Well monitoring and automation
• Security and surveillance
• Navigational aids
• Communication systems

For your remote power generation projects, consider a thermoelectric generator. Contact a product specialist and share your requirements. Combining your project knowledge with their product expertise will produce an effective solution.

Advantages of Thermoelectric Generators from MSJacobs-Cali