Control Valve Designed for On/Off Operation

Cutaway view of the Mark 76 on/off control valve,
a sliding gate design.
Image courtesy Jordan Valve

Not every fluid control application needs a modulating valve. In some cases, a two state control algorithm, flow or no flow, is the best solution. Opting for a less complex control method can deliver up front benefits of lower first cost and easier implementation. Continuing savings in maintenance time and the ease of understanding the control sequence accrue for the life of the installation.

The Mark 76 On/Off Control Valves, from Jordan Valve, are an advantageous choice for applications as described above. They exhibit very rapid opening and closing times with the short stroke sliding gate design. The pneumatically operated valve can be configured to open when pressure is applied, or to close. The counterforce spring returns the valve to its normal state when no air pressure is applied to the actuator. This allows the valve to be controlled using a small solenoid valve.

The sliding gate design does not use soft seats, but delivers tight shutoff and is suitable for steam service. The low air pressure requirements and short stroke required by the sliding gate contribute to the longevity of the Mark 76 in control applications.

More information is in the datasheet included below. Share your fluid control requirements of all types with valve application specialists, leveraging your own process knowledge and experience with their product application expertise to develop an effective solution.

Mark 76 On/Off Control Valve from Hile Controls of Alabama, Inc.

Bourdon Tube Pressure Gauge Manufacture

Even with the forward march of technology in process measurement, some methods in use for many years maintain their popularity due to performance, ruggedness, or simplicity that can be attractive for many applications. Mechanical pressure gauges certainly fall in that group.

Mechanical pressure gauges employing Bourdon tubes are found throughout industrial process control operations. They provide accurate and immediate indication of the pressure at their connection point, without the need for external power. It can be useful to see and understand how instruments are built and upon what principles they operate. The video included with this post shows the process.

Bourdon tube gauges rely on the principle that a flattened and bent tube will straighten and regain its circular cross section, to some predictable and repeatable degree, in response to an increase in the pressure of a fluid inside the tube. You can see it happen in the video. The balance of the gauge is a case, a face, and mechanical linkage to transfer the Bourdon tube motion into rotation of the indicator needle on the instrument face.

Watch the video. It's informative and well done. Wika, a globally recognized manufacturer of temperature, pressure, and level measurement instrumentation, produced the video at their manufacturing facility. Share your process instrumentation challenges and requirements with a process measurement specialist, leveraging your own knowledge and experience with their product knowledge and application expertise.

Turbine Flow Meters

Turbine flow meters area available in a wide range
of sizes and construction materials.
Image courtesy FTI Flow Technology, Inc.

Precision turbine flow meters are specially designed to accommodate a broad range of precise fluid measurement applications, though differing models and variants tend to be targeted at specific application conditions. They accommodate greater flow rates with lower pressure drops than other meters in their class. The turbine rotates as process fluid passes through the instrument, and special pickups placed around the perimeter of the meter sense the passage of the rotor blades. This produces a high-frequency digital output suitable for interfacing with an assortment of processing, 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 paragraph is mostly excerpted from "FT Series Turbine Flow Meters", an IOM published by Flow Technology, Inc. (document ID is TM-86675, Rev AG) ...with some editing.

A turbine flow meter is a volumetric flow measuring instrument. The flow sensing element is a freely suspended, bladed rotor positioned axially in the flow stream with the flowing fluid pushing against the blades. The rotational speed of the rotor is proportional to the velocity of the fluid. Since the flow passage is fixed, the turbine rotors rotational speed is also a true representation of the volume of fluid flowing through the flow meter. The rotation of the turbine rotor generates electrical pulses in the pickoff that is attached to the flow meter housing in close proximity to the turning rotor. Each one of these pulses represents a discrete volume of fluid. The frequency or pulse repetition rate represents the volumetric flow rate and the accumulated pulse total represents the total volume measured.

Maintenance

A turbine flow meter is a mechanical device. The primary moving part is the rotor, but its balance and bearings need to be kept in good working order to avoid offset of the flow reading. Regular maintenance commonly involves withdrawing of the rotor and internal parts from the body and conducting a cleaning and inspection for corrosion or contamination of the rotor assembly by accumulation of foreign material. In some cases where foreign material buildup is inevitable, a means to isolate and flush the meter with a solvent after use can contribute greatly to reducing the overall maintenance burden.

Installation

Electrical connection and grounding requirements for turbine flow meters are similar to other process measurement instruments. Mechanical installation requires consideration of a number of factors that my impact unit performance. Delivering properly conditioned flow to the instrument inlet and removing or dampening forces and conditions which may produce velocity profile disturbances is a key element of a successful installation. Paying careful attention to flow conditioning at the outset of installation and planning will yield results for the life of the unit. Here is an example of a recommended installation profile, courtesy of FTI Flow Technology, Inc.

Schematic representation of turbine flow meter installation.
Image courtesy FTI Flow Technology, Inc.

Summary

Turbine flow meters, with their simple, durable construction and wide operating range, are an effective and beneficial choice for a number of industrial process 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 effective solutions.

Radar Level Measurement

Non-contact radar level transmitter installed in process tank.
Image courtesy Tek-Trol

Radar is a means by which electromagnetic waves of short wavelength (microwaves) are used to detect the presence, distance and location of a remotely located object. While well known for its use in miltary and air traffic control applications, radar ranging technology is used in industrial processing to measure liquid and solids levels in containers of many types.

Condensed to a simple explanation, a radar level measurement instrument emits timed electromagnetic energy bursts, measuring the time interval from each burst emission to return. The emitter directs the microwaves toward the surface of the material to be measured. As the distance from the emitter to the material surface increases, so does the transit time of the wave on its round trip from emitter to media surface and back to a detector antenna. This transit time is proportional to the distance from the emitter to the media surface and can be used to calculate the media level.

Radar level transmitters can provide onboard processing of the raw signal, delivering a standard industrial process control signal which is scaled to a useful value range indicating percentage of tank fill, or some other useful representation of media level. It is necessary for the surface of the material to be measured to have properties which will reflect a sufficient amount of the radiation to allow a detection of the return signal. This is not problematical for most materials, but each application should be discussed with an instrumentation specialist to confirm suitability.

Radar level technology is utilized in a guided wave format, where the emitted energy travels down a tube extending into the medium, and non-contact configurations with the microwave emissions dispersing as they travel from the source antenna. Both types deliver excellent accuracy and have their specific application criteria where they may be preferred.

Properly selecting and applying level measurement instrumentation requires consideration of many operational and technological aspects of each process. Share your process measurement challenges with application specialists and leverage your own knowledge and experience with their product application expertise.

Radar Non-Contact Level Transmitter from Hile Controls of Alabama, Inc.

Wrap Up 2017 for Hile Controls of Alabama

The current year is closing out quickly. Here at Hile Controls of Alabama, we want to extend our thanks to all those that have supported our business and provided us with opportunities to build and improve our business and yours.

A number of product line expansions were put in place this past year.

• The Eurotherm product line was expanded to include programmable automation controllers.
• Equipment enclosure cooling equipment is now part of the Hile Alabama product mix with addition of the Advanced Cooling Technologies product line.
• HART communications software from ProComSol delivers consolidated solutions for working with HART based transmitters.
• Tektrol products for flow, level, temperature and pressure measurement, and control valves and analyzer systems empower our applications team to meet even more customer requirements and challenges.
• Premier Industries, a designer and manufacturer of proprietary specialty gas and hydraulic regulators, valves, and systems for a diverse range of applications and markets, is now represented by our company.

In addition to new products, we also continued to train and learn, in order to better meet whatever challenges we face. We look forward to every opportunity to serve our customers in the new year.

Advanced Mass Flow Meter and Controller for Gases

The EL-FLOW® Prestige is the latest mass flow controller
offering from Bronkhorst USA.
Image courtesy Bronkhorst USA

Bronkhorst is a globally recognized innovator in mass flow and pressure measurement and control. The company's EL-FLOW® Prestige incorporates their latest innovations in gas flow measurement and control.

The EL-FLOW® is essentially a thermal mass flow controller, and includes measurement hardware, microprocessor controller, and precision control valve in a single compact unit. Setpoint and output can be transferred to and from the unit via a PC connection, analog port, or one of several possible industrial communications protocols.

DeviceNet™, PROFIBUS DP, Modbus, PROFINET, EtherCAT® or FLOW-BUS

The instrument uses a new thermal principal for flow measurement, called Differential Temperature Balancing.  It is similar to traditional thermal mass flow measurement, but employs two heated sensors and a modified algorithm to process the comparative heat input to each. The innovation delivers a high degree of linearity, with improved stability to boost the controller accuracy.

There are several other innovations included in this latest version of the EL-FLOW® mass flow controller. More information is provided in the datasheet included below, but you are encouraged to share all your flow measurement and control challenges with process measurement and control experts. Leverage your own process knowledge and experience with their product application expertise to develop effective solutions.

EL-FLOW Prestige Mass Flow Controller and Flow Meter from Hile Controls of Alabama, Inc.

Hile Controls of Alabama Expands Product Offering

Continuing its drive to provide top flight solutions to industrial process measurement and control challenges, Hile Controls of Alabama has added several new lines of instruments and equipment to its offering.

• Tektrol provides process measurement and control products for flow, level, temperature and pressure measurement and control valves and analyzer systems.
• Premier Industries is a designer and manufacturer of proprietary specialty gas and hydraulic regulators, valves, and systems for a diverse range of applications and markets.

More will be coming to illustrate the quality products offered by these new lines for Hile. Detailed information is available through a quick contact with our office. Share your process measurement and control challenges, leveraging your own knowledge and experience with the product application expertise at Hile Controls of Alabama to develop the best solution.