Pressure Switches - The Stalwart of Pressure Instrumentation

Pressure switch in an
explosion-proof housing.
(United Electric)

A pressure switch is an electromechanical device that detects the presence of fluid pressure and responds by opening or closing an electrical or pneumatic circuit.

In heavy industry, pressure switches are used in virtually every power plant, refinery, chemical plant, paper mill, steel mill, or other manufacturing plant that blends ingredients.

Pressure switches are simple devices. They can be broken down to their major parts: a pressure port or connection; a sensor that moves in relationship to changing pressures; an electrical or pneumatic switch that opens or closes upon movement; and finally a housing that protect the internals of the pressure switch from the ambient conditions.

Differential pressure switch.
(United Electric)

Pressure switches use a variety of sensing elements such as diaphragms, bellows, bourdon tubes, or pistons. In most cases, the movement of these sensors, caused by pressure fluctuation, is transferred to a set of electrical contacts to open or close a circuit. Normal status of a switch is the resting state. A pressure switch will be in its “normal” status when it senses low or minimum pressure. For a pressure switch, “normal” status is any fluid pressure below the trip threshold of the switch.

One of the earliest and most common designs of pressure switch was the bourdon tube pressure sensor accompanied by a mercury switch. A mercury switch is a position sensitive glass bulb containing mercury that flows over, or away from, the electrical contacts. When pressure is applied, the bourdon tube attempts to straighten, and moves enough to slightly tilt the mercury switch. Many of these kind of pressure switches were sold on steam boilers, and while they became a de facto standard, they were sensitive to vibration and breakage of the mercury bulb.

NO vs. NC electrical switch contacts.

The most common electrical switch used in pressure switches are "microswitch" type. These are also called "snap switches" because they are actuated by very little physical force, through the use of a tipping-point mechanism. These type of switches offer reliability and repeatability. They also are available in many different voltages and current ratings

One of the criteria of any pressure switch is the deadband or (reset pressure differential). This setting determines the amount of pressure change required to reset the switch to its normal state after it has tripped.  The “differential” pressure of a pressure switch should not to be confused with differential pressure switch, which actually measures the difference in pressure between two separate pressure ports.

When selecting pressure switches you must consider the electrical requirements (volts, amps, AC or DC), the area classification (hazardous, non-hazardous, general purpose, water-tight), pressure sensing range, body materials that will be exposed to ambient contaminants, and wetted materials (parts that are exposed to the process media).

It's always a good idea to discuss your application with an expert before specifying or installing a pressure switch. You'll end up saving time and money, and ensure long, safe operation.

For more information on pressure switches, contact Miller Energy by visiting https://millerenergy.com or by calling one of these numbers: In New Jersey 908-755-6700. In Pennsylvania 610-363-6200.

Bimetal Thermometers for Industrial Process Measurement

Bimetal thermometers have a place in modern process
measurement systems.
Image courtesy Wika

Temperature measurement is everywhere, with broad ranges of accuracy, range and other operational requirements to bring the measurement data into a process management or control system. The process could be as simple as measuring a cooking temperature, or a part of a complex refining operation. Temperature provides an indication of heat energy level that is used in many ways throughout process control.

Though there are many instruments and technologies available to measure temperature, one that everyone is familiar with is the dial thermometer. A familiar numeric scale and a pointer indicate the temperature at the sensing location. Even within the product range of dial thermometers, there are several differing methods utilized to produce a temperature reading. One of these is the bimetal thermometer.

A bimetallic thermometer is named for the mechanism that responds to process temperature and provides the force to position the indicator needle over the scale on the dial face. A bimetal is formed from two dissimilar metals bonded together. The metals expand and contract at different rates in response to a change in their temperature. A bimetal thermometer relies on the predictable deformation of a bimetal spring or strip in response to a temperature change. The mechanical deformation is transformed into rotational movement of the indicating needle on the instrument face where the corresponding temperature can be read by a technician or operator. This design principle has been in use throughout laboratories, kitchens, and industry for many years and has proven to be predictably accurate, stable, and rugged.

The major advantages of the bimetallic thermometer are its relative cost, ease of use, and ability to function without any external power source. This class of instruments provides operability up to +1000°F.

When applying dial faced thermometers, there are several main considerations.

• Scale - The display behind the indicating pointer. The scale divisions impact the instrument's accuracy at indicating process temperature.  
• Range - The physical suitability of the instrument to be exposed to the temperatures which may be present in the process. May be the same as scale.
• Dial Size - Larger diameter dial faces make reading the instrument indications easier.
• Connection - There are numerous options for the way in which the probe or stem, which is inserted into the process, attaches to the dial portion or head of the instrument. Common arrangements are back, side, or bottom connected. If the head cannot be rotated or angled, the connection attributes may be the sole determinant of how the dial face is oriented.
• Stem Length - The stem extends from the head into the process. Coordinating the stem length with the insertion depth into the process and the placement of the instrument is important to achieving a useful and ergonomic installation.
• Materials of Construction - Make sure the selected instrument is rugged enough to withstand expected environmental conditions at the installation site.

These are only the primary considerations. Share your operational requirements with a product specialist. Leverage your own knowledge and experience with their product application expertise to develop the optimal solution.

Mass Flow Controllers for Precise Dosing

Mass Flow Controller - Cutaway View
Image courtesy Brooks Instrument 

There are processing applications that require very accurate flow or dosing control of added constituents. The applications are diverse, ranging from controlled gas flow to precise metering of product fluid components. The ability to accurately and reliably measure and regulate mass flow of a fluid into a process is a common task in process measurement and control.

Thermal mass flow measurement, in basic operation, infers mass flow by measuring the heat dissipation from a heated temperature sensor and comparing it to an unheated reference temperature sensor. The heat dissipation is directly proportional to the mass flow of gas or liquid.

Thermal mass flow meters are very popular for several reasons. They have no moving parts, have a fairly unobstructed flow path, are accurate over a wide range of flow rates, calculate mass flow rather than volume, measure flow in large or small piping systems, and do not need temperature or pressure compensation.

For a process control application, accuracy and real time delivery of measurement data are key factors. Advanced smart controls with a range of communications options that will interface with a variety of devices across a choice of platforms bring high levels of functionality and ease of use to an application. For gas applications, smart technology allows one device to be applied to multiple gas types and ranges without removing the flow meter from the system. Product selection is enhanced by the availability of instruments targeted at a range of applications.

Share your flow measurement and control challenges with process measurement and control specialists. Leverage your own process knowledge and experience with their product application expertise to develop effective solutions.

Innovative Non-Contact Radar Liquid Level Transmitter

Pulsar R86 non-contact radar level transmitter.
Image courtesy Magnetrol

Level measurement of liquids and solids in containers, silos, tanks and other vessels is an essential part of many processing operations. Accurate and reliable measurement of solids or liquid level contributes to operational success, as well as enhancing safety, both of which contribute to the bottom line and successful operation.

Magnetrol, globally recognized innovator in flow and level measurement, incorporates years of experience into their latest version of non-contact radar level measuring instruments. The incremental improvements contribute to easier, more flexible installation and better performance.

The R86 is a 26 GHz level transmitter applicable across a wide range of requirements in many industries. Benefits of the 26 GHz radar signal, with its smaller wavelength, are a smaller antenna and improved 1mm resolution. The narrower beam from the antenna makes positioning the transmitter less restrictive, with easier accommodation for vessel fixtures or geometry. Advanced on board diagnostics supplement the improved performance and deliver the information needed to maintain proper operation and process visualization. A broad range of antennas and mountings are available for the R86, accommodating various tank sizes, fittings, and temperatures

More information on the Pulsar R86 is provided in the brochure included below. Share your level measurement challenges and requirements with a process measurement specialist. Employ the leverage of their product application expertise to your own process knowledge and experience to develop an effective solution.

Magnetrol Non-Contact Radar Level Transmitter Pulsar R86 from Miller Energy, Inc.

Composite Solenoid Valves for Water Purification Systems

Composite construction, along with other targeted features,
make the ASCO 212 Series a good choice for membrane water
purification systems and equipment.
Image courtesy Emerson - ASCO

Water purification systems and equipment present a unique set of fluid control challenges. Purified water is aggressive and will rapidly corrode most metallic parts. Additionally, strong chemicals are utilized in some systems for cleaning or regeneration, presenting yet another longevity challenge for the process valves needed to operate a system or equipment skid.

ASCO, an Emerson Brand, has developed a line of solenoid operated valves targeted at membrane based water purification applications. These applications include desalination skids and a broad range of ultrafiltration, and reverse osmosis equipment installations.

The Series 212 delivers substantial benefit to customers, through its basic construction, design and ease of use.

• Compliance and certification listings with applicable current standards and codes.
• Short lead time with quick-ship program from distributors.
• High reliability - tested up to one million cycles.
• Ease of connectivity, available as Turn & Lock, NPT thread, or solvent bond.
• FasN connection system enables greatest equipment design and assembly flexibility.
• Normally open and normally closed versions available.

More detail is provided in the datasheet included below. Share your fluid control challenges with process control specialists at Miller Energy, leveraging your own knowledge and experience with our product application expertise to develop effective solutions.

Solenoid Valves for Water Conditioning and Purification Systems and Equipment from Miller Energy, Inc.

Process Gas Chromatographs and Flare Monitoring

Flare monitoring requires specialized instruments to
meet regulatory requirements.

Gas chromatography is a common analysis tool employed in many areas of industry, including oil and gas, pharmaceutical, chemical, and others. Yokogawa Corporation of America  has been delivering top tier industrial GC performance with their GC8000 Process Gas Chromatograph for use in oil and gas, and other industrial applications.

Modern regulatory requirements for flare gas management highlight an application area for gas chromatography. Yokogawa provides an analysis of the requirements for flare monitoring, related regulatory compliance, and how various measurement and analysis techniques and equipment can aid in delivering a successful compliance plan. Industrial gas chromatographs can play a part in a compliance plan for flare monitoring.

In addition to the ruggedness and reliability for which Yokogawa gas chromatographs are well known, the GC8000 brings a number of innovations and improvements to the company’s process gas chromatography product offering that deliver easier operation and more efficient utilization.

• Color touchscreen HMI for easy operation
• Advanced predictive diagnostics and software functions monitor key performance indicators during each analysis to verify analyzer is operating within proper tolerances.
• Parallel chromatography is made practical through the use of the GC Modules provided as part of the GC8000. Virtual GCs can be set up inside a single GC with GC Modules to measure multiple streams simultaneously.

More detail is available on the GC8000 Process Gas Chromatograph, the culmination of Yokogawa’s 55 years of experience in the field. For more information, or to discuss your application specifics, contact a product specialist.

Focus Your Product Selection Quickly With This Useful Tool

The Process Instrumentation Selection Tool from Yokogawa
enables the user to make detailed product selections
with a few clicks.
Image courtesy Yokogawa

In the process measurement sphere, manufacturers respond to market demand and their own growth goals by offering integrated product solutions. This can result in a product offering that is extensive, with many different products that can be applied to the same task. There are often several, or many, choices to winnow down to a final selection. Product research and evaluation for application suitability takes time. In today's business environment, time is what we never seem to have in sufficient quantity. Finding ways to streamline any process can be beneficial.

Yokogawa is one of those companies that manufactures a broad range of products for process measurement. Whatever your process measurement needs, it is likely the Yokogawa has an effective solution that delivers solid quality and performance.

In a past blog posting, we introduced readers to Process Instrument Selection Tool. With some basic information about your application, a few clicks can quickly deliver access to the best product selection for an application. It is simple, rapid and accurate. The product selector covers 24 basic measurement and instrumentation classifications. We are posting about it again because it has been so successful in helping customers zoom in on the right product solutions for their process measurement applications.

The Product Finder is accessible through a number of links throughout Yokogawa's network of representatives. Clicking the link lands you on the start page of the Product Finder. Try it out, and share your process measurement and control challenges with application specialists for even more leveraging of your own process knowledge and experience toward an effective solution.

Best Temperature Control Performance Starts With a Match of Sensor Configuration to Application

A specially configured temperature sensor can improve
measurement response and process control.
Image courtesy Applied Sensor Technologies

There are more temperature controlled operations than any of us could count in a lifetime, each with a set of signature performance requirements and design challenges. Matching the means of temperature measurement, the control loop characteristics, and heat delivery method to the application are essential to achieving successful operation.

Step one is to measure the process temperature. This sounds simple until you start researching products and technologies for measuring temperature. Like the temperature controlled operations mentioned previously, they are numerous. To filter the possible candidates for temperature sensing devices, consider these aspects of your application and how well a particular sensor may fulfill your requirement.

• Response Time - How rapidly the sensor will detect a change in process temperature is a function of how the sensor is constructed and how it is installed. Most temperature sensors are enclosed or encapsulated to provide protection for the somewhat vulnerable sensing element. Greater mass surrounding the sensing element, or a shape that inhibits heat transfer from the process to the sensor, will slow sensor response. Whether the slower response time will adversely impact process operation needs to be considered. More consideration is due to the manner in which the temperature sensor assembly is installed. Not all applications involve a fluid in which the sensor assembly can be conveniently immersed, and even these applications benefit from careful sensor placement.
• Accuracy - Know what your process needs to be effective. Greater levels of accuracy will generally cost more, possibly require more care and attention to assure the accuracy is maintained. Accuracy is mostly related to the type of sensor, be it RTD, thermocouple, or another type.
• Sensitivity - Related to the construction, installation, and type of sensor, think of sensitivity as the smallest step change in process temperature that the sensor will reliably report. The needs of the process should dictate the level of sensitivity specified for the temperature sensor assembly.

Take a simple application as an illustration. Heat tracing of piping systems is a common function throughout commercial and industrial settings experiencing periods of cold weather. Electric heat trace installations benefit from having some sort of control over the energy input. This control prevents excessive heating of the piping or applying heat when none is required, a substantial energy saving effort. A temperature sensor can be installed beneath the piping's insulation layer, strapped to the pipe outer surface. A specially designed sensor assembly can improve the performance of the sensor and the entire heat trace control system by enhancing the response time of the temperature sensor. A right angled sheath permits insertion of the sensor beneath the piping insulation while orienting the connection head upright. A surface pad at the tip of the sheath increases the surface contact with the pipe to provide faster sensor response. The surface pad is a metal fixture welded to the sensing end of the temperature sensor assembly. It can be flat, for surface temperature measurements, or angled for installation on a curved surface, like a pipe. The increased surface contact achieved with the surface pad promotes the conduction of heat to the sensor element from the heated pipe in our illustration. This serves to reduce and improve the response time of the sensor. Adding some thermally conductive paste between the pad and the pipe surface can further enhance the performance. While the illustration is simple, the concepts apply across a broad range of potential applications that do not allow immersion of the temperature assembly in a fluid.

A simple modification or addition of an option to a standard sensor assembly can deliver substantially improved measurement results in many cases. Share your temperature measurement requirements and challenges with a process measurement specialist. Leverage your own process knowledge and experience with their product application expertise.

Special RTD Temperature Sensor Configuration for Heat Trace Applications from Miller Energy, Inc.

Maintenance Procedures - Yokogawa ADMAG TI Series AXW Magnetic Flowmeter

The AXW series of magnetic flow meters is available in
a range of sizes with corrosion resistant lining.
Image courtesy Yokogawa

The ADMAG AXW™ series of magnetic flow meters has been developed based on Yokogawa's decades of experience in the design and manufacture of magnetic flowmeters. The AXW series continues the tradition of high quality and reliability that has become synonymous with the Yokogawa name.

The AXW series is ideal for industrial process lines, and water supply and sewage applications. With outstanding reliability and ease of operation, developed on decades of field-proven experience, the AXW will increase user benefits while reducing total cost of ownership.

Magnetic flow meters, also called electromagnetic flow meters or "magmeters", operate on a very simple principal. An electrically conductive liquid moving through a magnetic field will generate a voltage that is related to the velocity of the liquid. Magnetic flow meters have no moving parts and present little to no pressure drop to the piping system into which they are installed.

Sizes are available from 500 to 1800 mm (20 to 72 inch.) with a wide liner selection such as PTFE, natural hard rubber, natural soft rubber, and polyurethane rubber. The line accommodates industry standard process connections such as ASME, AWWA, EN, JIS, and AS flange standards. A submersible version is also available.

Care and maintenance for magnetic flow measurement devices is simple and minimal. The manual included below provides basic guidelines for maintenance procedures of ADMAG TI (Total Insight) Series AXW magnetic flowmeters. Share your flow measurement challenges with process instrument specialists, leveraging your own knowledge and experience with their product application expertise.

Maintenance Procedures for Yokogawa ADMAG TI Series AXW Magnetic Flow Meter from Miller Energy, Inc.

White Paper About Safety Compliance for Solenoid Valves

Solenoid valves for industrial process control applications
Image courtesy Asco Valve

Regulatory modifications have raised important issues in design and use of industrial safety systems. Certain changes in IEC 61508, now being widely implemented, mean that designers and users who desire full compliance must give new consideration to topics such as SIL levels and the transition to new methodologies.

In particular, these issues can impact the selection of solenoid valves and prepackaged redundant control systems (RCS) for implementation in a safety instrumented system (SIS). Such selections may also be affected by how experienced valve suppliers are at dealing with complex new compliance methodologies.

These issues are especially applicable to the oil, gas, chemical, and power industries - in applications such as safety shutdown systems, boilers, furnaces, high-integrity protection systems (HIPS), and more. These issues are of concern to safety engineers and reliability engineers, as well as to process engineers, engineering executives, and plant managers.

This report, a white paper made available by ASCO Valve, will address these issues in developing a compliant safety instrumented system using valves and redundant control systems. Making the right choices in safety system planning and in valve supplier selection can affect design time, costs, and effort — as well as the safety of the plant itself.

Asco Safety Systems Solenoid Valve Selection Guide from Miller Energy, Inc.

Top End Guided Wave Radar Level Transmitter

Magnetrol's model 706 embodies the best of guided
wave radar level measurement.
Image courtesy of Magnetrol

The Eclipse Model 706 is Magnetrol's loop powered high performance guided wave radar level transmitter. It incorporates many of the company's latest innovations into a single instrument capable of meeting the demanding requirements of an array of industrial applications.

Product improvements include increased signal to noise ratio, suitability for use with low dielectric media, and the ability to deliver accurate indication under foaming, flashing, or other challenging conditions. An extended probe offering enables use in measuring interface, liquified gas, even bulk solids.

The instrument is suitable for overfill applications, and does not use algorithms to infer measurements in a dead zone that may occur near the top of the probe in some other designs. The Eclipse 706 delivers true measurement right up to the process flange. Upgraded electronics allow the unit to be pre-configured prior to shipment, if requested. Additionally, the widest range of communications options is available.

For more information, share your level measurement challenges with a process measurement specialist. Leverage your own process knowledge and experience with their product application expertise to develop effective solutions.

Eclipse Model 706 High Performance Guided Wave Radar Level Transmitter from Miller Energy, Inc.

Magnetic Level Indicators

Configurations of magnetic level gauges
Image courtesy Orion/Magnetrol

Fluid process control operations often involve vessel or tank storage of liquids. Continuous and accurate indication of the liquid level within the tank is an essential data point for process control decision making and safety. Several methods and instrument types are available for tank level measurement, each with its own set of attributes that may be advantageous for a particular installation. Selection criteria for a tank liquid level indicator may include:

• Direct or indirect measurement of level
• Level measurement accuracy and reliability
• Tank shape, regular or irregular
• Media compatibility with measurement device
• Requirements for maintenance or calibration
• Compatibility with process temperature and pressure range
• Local display and visibility
• Level indication signal type and transmission
• Level alarm switches or other indicators

The selection of a magnetic level indicator, also referred to as a magnetic level gauge, for the project will likely be based upon at least one of the instrument's strengths. Magnetic level gauges have a host of potentially positive features for level indication.

• Continuous level measurement
• Operable without electric power
• Direct visual tank fluid level indication, regardless of tank shape or profile.
• Wide range of operating temperature and pressure
• Breakage resistant construction
• Range of construction materials available to accommodate corrosive media
• Measuring indicators, switches, and transmitters mounted externally, without contacting the medium being measured.
• Low maintenance operation.
• Readable level indication from greater distance than glass sight gauges.
• Applicable to large fluid level ranges with a single instrument.

Magnetic level indicators have a strong position in the tank liquid level measurement field and should be considered as a candidate for fulfilling those application requirements. There are many options available to customize the level indicator for each specific application. I have included a technical data sheet from Orion Instruments, a manufacturer of level instrumentation, for more detail. Share your application challenges with a sales engineer that specializes in level measurement. Combining your process knowledge with their product application expertise will yield positive solutions.

Magnetrol Orion Magnetic Liquid Level Indicators from Miller Energy, Inc.

Magnetic Flowmeters: Principles and Applications

Magnetic flowmeters are well suited for flow measurement
with conductive fluids.
Image courtesy Yokogawa

Fluid process control operations rely on the operator's ability to accurately determine qualities and quantities of liquid or gaseous materials. In terms of appraising and working with fluids (such as liquids, steam, and gases) the flowmeter is a staple tool, with the simple goal of expressing the delivery of a subject fluid in a quantified manner. Measurement of media flow velocity can be used, along with other inputs, to determine volumetric or mass flow. The magnetic flowmeter, also called a magmeter, is one of several technologies used to measure fluid flow.

In general, magnetic flowmeters are sturdy, reliable devices able to withstand hazardous environments while returning accurate measurements to operators of a wide variety of processes. The magnetic flowmeter has no moving parts. The operational principle of the device is powered by Faraday’s Law, a fundamental scientific principle stating that a voltage will be induced across any conductor moving at a right angle through a magnetic field, with the voltage being proportional to the velocity of the conductor. The principle allows for an inherently hard-to-measure quality of a substance to be expressed via the magmeter. In a magmeter application, the meter produces the magnetic field referred to in Faraday’s Law. The conductor is the fluid. The actual measurement of a magnetic flowmeter is the induced voltage corresponding to fluid velocity. This can be used to determine volumetric flow and mass flow when combined with other measurements.

The magnetic flowmeter technology is not impacted by temperature, pressure, or density of the subject fluid. It is however, necessary to fill the entire cross section of the pipe in order to derive useful volumetric flow measurements. Faraday’s Law relies on conductivity, so the fluid being measured has to be electrically conductive. Many hydrocarbons are not sufficiently conductive for a flow measurement using this method, nor are gases. On the other hand, water and aqueous solutions tend to exhibit sufficient conductivity to apply magmeter technology.

Magmeters apply Faraday’s law by using two charged magnetic coils; fluid passes through the magnetic field produced by the coils. A precise measurement of the voltage generated in the fluid will be proportional to fluid velocity. The relationship between voltage and flow is theoretically a linear expression, yet some outside factors may present barriers and complications in the interaction of the instrument with the subject fluid. These complications include a higher amount of voltage in the liquid being processed, and coupling issues between the signal circuit, power source, and/or connective leads of both an inductive and capacitive nature.

In addition to salient factors such as price, accuracy, ease of use, and the size-scale of the flowmeter in relation to the fluid system, there are multiple reasons why magmeters are the unit of choice for certain applications. They are resistant to corrosion, and can provide accurate measurement of dirty fluids – making them suitable for wastewater measurement. As mentioned, there are no moving parts in a magmeter, keeping maintenance to a minimum. Power requirements are also low. Instruments are available in a wide range of configurations, sizes, and construction materials to accommodate various process installation requirements.

As with all process measurement instruments, proper selection, configuration, and installation are the real keys to a successful project. Share your flow measurement challenges of all types with a process measurement specialist, combining your own process knowledge and experience with their product application expertise to develop an effective solution.

Miller Energy Expands Product Offering

Miller Energy is now a distributor of Asco solenoid
valves for a wide range of general and special applications

Miller Energy, through its acquisition of a New Jersey based distributor, has greatly expanded the company's offering of solenoid valves, pneumatic system components, and fluid handling and control components.

A solenoid is an electrical device, converting electrical energy input to a linear mechanical force. Solenoids are used to provide rapid two state mechanical movement of other devices. In process control applications, those devices are often fluid control valves.

At the basic level, a solenoid is an electromagnetic coil and a metallic rod or arm. Electrical current flow in the coil creates a magnetic field which will position the rod in one of two locations, depending upon whether the coil is energized. The movable component of the solenoid is linked to, or part of, the operating mechanism of another device. This allows the switched electrical output of a controller to regulate mechanical movement in another device and cause a change in its operation. A common solenoid application is the operation of small valves.

A plunger solenoid contains a movable ferrous rod, sometimes called a core, enclosed in a tube sealed to the valve body and extending through the center of the electromagnetic coil. When the solenoid is energized, the core moves to its equilibrium position in the magnetic field. The core is also a functional part of valve operation. It's repositioning causes a designed changed in the valve operating status (open or close). There are countless variants of solenoid operated valves exhibiting particular operating attributes designed for specific types of applications. In essence, though, they all rely on the electromechanical operating principle outlined here.

A solenoid valve is a combination of two functional units.

• The solenoid (electromagnet) described above.
• The valve body containing one or more openings, called ports, for inlet and outlet, and the valve interior operating components.

Flow through an orifice is controlled by the movement of the rod or core. The core is enclosed in a tube sealed to the valve body, providing a leak tight assembly. A controller energizing or de-energizing the coil will cause the valve to change operating state between open and closed, regulating fluid flow. There are almost countless variants of solenoid operated valves, specifically tailored for applications throughout industrial, commercial, and institutional operations.

The document provided below illustrates a portion of the broad array of solenoid valves available for industrial control applications. Share your fluid control requirements and challenges with an application specialist. Leverage your process knowledge and experience with their product application expertise to produce effective solutions.

ASCO Solenoid Valve Product Line Overview from Miller Energy, Inc.

Bulb and Capillary Temperature Switches

General purpose temperature switch with bottom connection
for capillary and bulb specific for each application.
Image courtesy United Electric Controls

Not all processes or operations require the use of state of the art technology to get the desired results. Part of good process design is matching up the most appropriate methods and technology to the operation.

One method of changing the state of a switch in response to a process temperature change is a bulb and capillary temperature switch. The switch operation produces a state change in the mechanical switch when the temperature of a process control operation crosses a certain threshold. Bulb and capillary switches have the advantage of operating without electricity, simplifying their application.

The physical operating principle behind the capillary thermostat relies on the use of a fluid. The fluid inside the thermostat expands or contracts in response to the temperature at the sensing bulb. The change in fluid volume produces a force upon a diaphragm or other mechanical transfer device. The diaphragm is connected to, and changes the status of, an adjoining circuit using a snap action switch. For example, a main use of the operating principle in action is when a commercial food company relies on the capillary switch to control temperature related to processing and distribution. Each individual use of a bulb and capillary thermostat is specifically designed based on manufacturer and industry specifications, all of which apply the same physical principle of fluid based physics.

Because of their simplicity and comparatively modest cost, commercial versions of bulb and capillary switches find application throughout residential and commercial settings. Some common applications include warming ovens, deep fat fryers, and water heaters. The HVAC industry uses capillary and bulb switches because the rate of temperature change found in their applications fits the adjoining range offered by the bulb and capillary type switches. Operation of the temperature switches is subject to a few limitations. The switching point is often fixed, so the application must be without a requirement for an adjustable setpoint. The temperature range over which the switches are suitable is comparatively limited, with a matching of the bulb and capillary fluid system to the application temperature range a necessary task in product selection. Within its proper sphere of use, though, bulb and capillary temperature switches offer simple, reliable operation, with little requirement for maintenance.

Bulb and capillary switches are typically used to evaluate average temperature and are especially useful for applications where the temperature is to be maintained at a well-known, consistent value. The bulb portion can be configured to accommodate mounting within the media to be controlled. The devices can be applied effectively to liquid and gaseous media when the proper bulb is used.

Industrial versions of bulb and capillary switches are fitted with appropriate housings for the installation environment. Hazardous location installation can be accommodated, as well as high current ratings and auxiliary functions. There are almost countless variants of bulb and capillary temperature switches available. Don’t overlook these simple mechanical devices as candidates for application in any temperature control process. Share your application requirements and challenges with product specialists for useful recommendations.

Temperature, Pressure, Vacuum, and Differential Switches from Miller Energy, Inc.

Application of Load Cells in Process Measurement

The advanced model G5 can handle input signals from multiple load cells
Image courtesy of BLH Nobel

In industrial application of process measurement and control, principles of the physical sciences are combined with technology and engineering to create devices essential to modern high speed, high accuracy system operation. Years of research, development, and the forward march of humanity’s quest for scientific knowledge and understanding yields packaged devices for process measurement that are easily applied by system designer and operators.

Load cells are the key components applied to weighing component or processed materials in modern industrial operations. Load cells are utilized throughout many industries related to process management, or just simple weighing operations. In application, a load cell can be adapted for measurement of items from the very small to the very large.

In essence, a load cell is a measurement tool which functions as a transducer, predictably converting force into a unit of measurable electrical output. While many types of load cells are available, one popular cell in multiple industries is a strain gauge based cell. Strain gauge cells typically function with an accuracy range between 0.03% and 0.25%. Pneumatically based load cells are ideal for situations requiring intrinsic safety and optimal hygiene. For locations without a power grid, there are even hydraulic load cells, which function without need for a power supply. These different types of load cells follow the same principle of operation: a force acts upon the cell (typically the weight of material or an object) which is then returned as a value. Processing the value yields an indication of weight in engineering units.

For strain gauge cells, deformation is the applied operational principal, where extremely small amounts of deformation, directly related to the stress or strain being applied to the cell, are output as an electrical signal with value proportional to the load applied to the cell. The operating principle allows for development of devices delivering accurate, precise measurements of a wide range of industrial products.

Load cell advantages include their longevity, accuracy, and adaptability to many applications, all of which contribute to their usefulness in so many industries and applications. A common place to find a strain gauge load cell in use is off a causeway on a major highway at a truck weigh station. Through innovation, load cells have been incorporated in an efficient measuring system able to weigh trucks passing through the station, without having each stop. Aircraft can be weighed on platform scales which utilize load cells, and even trains can be weighed by taking advantage of the robust and dependable nature of the transducers.

Thanks to their widespread incorporation and the sequential evolution of technology, load cells are a fantastically useful tool in process measurement and control. Share your process weighing challenges with application experts, combining your own process expertise with their product knowledge to develop an effective solution.

Product Update: SMARTDAC+ GX/GP Series Recorders & GM Series Data Acquisition System Release 4

Updated SMARTDAC line of data acquisition instruments
Image courtesy Yokogawa

Yokogawa Electric Corporation announced it's Release 4 of the SMARTDAC+® GX series panel-mount type paperless recorder, GP series portable paperless recorder, and GM series data acquisition system.

With this latest release, new modules are provided to expand the range of applications possible with SMARTDAC+ systems and improve user convenience. New functions include sampling intervals as short as 1 millisecond and the control and monitoring of up to 20 loops.

Overview

Recorders and data acquisition systems (data loggers) are used on production lines and at product development facilities in a variety of industries to acquire, display, and record data on temperature, voltage, current, flow rate, pressure, and other variables. Yokogawa offers a wide range of such products, and is one of the world’s top manufacturers of recorders. Since releasing the SMARTDAC+ data acquisition and control system in 2012, Yokogawa has continued to strengthen it by coming out with a variety of recorders and data acquisition devices that meet market needs and comply with industry-specific requirements and standards.

With this release, Yokogawa provides new modules with strengthened functions that meet customer needs for the acquisition and analysis of detailed data from evaluation tests. These modules decrease the cost of introducing a control application by eliminating the need for the purchase of additional equipment.

Enhancements

The functional enhancements available with Release 4 are as follows:

High-speed analog input module for high-speed sampling.

To improve the safety of electric devices such as the rechargeable batteries used in everything from automobiles to mobile devices, evaluation tests must be conducted to acquire and analyze detailed performance data. For this purpose, sampling at intervals as short as 1 millisecond is desirable. However, this normally requires an expensive, high-performance measuring instrument. When the new high-speed analog input module, a SMARTDAC+ system can sample data at intervals as brief as 1 millisecond, which is 1/100th that of any preceding Yokogawa product. This is suitable for such high performance applications such as measurement of the transient current in rechargeable batteries to vibration in power plant turbines. A dual interval function has also been added that enables the SMARTDAC+ to efficiently and simultaneously collect data on slowly changing signals (e.g., temperature) and quickly changing signals (e.g., pressure and vibration).

PID control module for control function

In applications that need both control and recording, such as controlling the temperature of an industrial furnace or the dosage process at a water treatment plant, there is a need for systems that do not require engineering and can be quickly and easily commissioned. In a typical control and monitoring application, a separate recorder and controller is required to control temperature, flow rate and pressure. At the same time, a data acquisition station must communicate with the controller to ensure data is being capture and recorded. It is time consuming and oftentimes confusing, to ensure the controller and the data acquisition station is communicating seamlessly. By combining continuous recording function of the SMARTDAC+ and PID control module into a single platform, customers can now seamlessly control and record critical process data in one system. The SMARTDAC+ can control, monitor and record up to 20 loops. Each PID control module comes with 2 analog inputs, 2 analog outputs, 8 digital inputs and 8 digital outputs.

Four-wire RTD/resistance module for precise temperature measurement

While three-wire RTDs are widely used in many fields such as research institutes to manufacturing, some applications require higher level of precision and accuracy that is only possible with 4-wire RTDs. A 4-wire RTD is the sensor of choice for laboratory applications where accuracy, precision, and repeatability are extremely important. To satisfy this need, Yokogawa has released a 4-wire RTD/resistance module for the SMARTDAC+.

Target Markets

GX series: Production of iron and steel, petrochemicals, chemicals, pulp and paper, foods, pharmaceuticals, and electrical equipment/electronics; water supply and wastewater treatment facilities.

GP series: Development of home appliances, automobiles, semiconductors, and energy-related technologies; universities; research institutes.

GM series: Both of the above target markets.

For more information on the SMARTDAC+ GX/GP Series Recorders & GM Series Data Acquisition System contact Miller Energy at (800) 631-5454 or by visiting the company website.

WirelessHART Toxic and Combustible Gas Detector

Vanguard WirelessHART toxic and combustible
gas detector for industrial safety use.
Image courtesy United Electric Controls

Earlier this year, United Electric Controls released its Vanguard WirelessHART gas detector for use in a wide range of industrial settings. Detecting potentially hazardous levels of toxic or combustible gases is an essential element of plant safety where these gases are employed. The Vanguard detector integrates seamlessly into existing WirelessHART networks and asset management systems. A battery lifespan of 5 years and a design that provides in-place test and calibration mean there will be little burden to maintaining the proper operation of the unit.

More detail is provided in the brochure included below. The Vanguard incorporates solid construction and design features to deliver ease of use and long service life. Share your gas detection and process measurement challenges with instrumentation specialists. Combining your own process experience and knowledge with their product application expertise will result in an effective solution.

WirelessHART Gas Detector for Toxic and Combustible Gas from Miller Energy, Inc.

Level and Flow Instruments for Hygienic Applications

Magnetrol is a globally recognized leader in the manufacture of flow and level instrumentation for industrial scale applications. The products employ a range of differing technologies to provide measurement precision across an array of challenging applications. The informational piece included below highlights Magnetrol's products intended for use in industries, such as pharma or food processing, where special materials and product design are employed to meet the special requirements of hygienic processing.

Share your flow and level measurement challenges with process instrumentation experts, combining your own knowledge and experience with their expertise to develop effective solutions.

Life Science Applications and Products - Magnetrol from Miller Energy, Inc.

Pump Protection Using Thermal Dispersion Flow Switches

Thermal dispersion flow switches have advantages
when applied for pump protection
Image courtesy Magnetrol

Good practice for installing industrial pumps calls for inclusion of protective devices to assure that the pump is not exposed to conditions beyond its design intent. Monitoring liquid flow is a useful method for determining if a pump is operating within a safe range.

There are numerous methods of verifying flow in piping connected to a pump. Magnetrol, globally recognized manufacturer of flow and level measurement technologies, offers up their assessment of various pump protection measures and a recommendation for what they consider an advantageous choice for flow measurement in a pump protection application.

Magentrol's white paper is included below, and you can share your flow and level measurement challenges with application experts for help in developing effective solutions.

Pump Protection Using Thermal Dispersion Switches from Miller Energy, Inc.