Introduction to Industrial Control Systems

Control systems are computer-based systems that are used by many infrastructures and industries to monitor and control sensitive processes and physical functions. Typically, control systems collect sensor measurements and operational data from the field, process and display this information, and relay control commands to local or remote equipment. In the electric power industry they can manage and control the transmission and delivery of electric power, for example, by opening and closing circuit breakers and setting thresholds for preventive shutdowns. Employing integrated control systems, the oil and gas industry can control the refining operations on a plant site as well as remotely monitor the pressure and flow of gas pipelines and control the flow and pathways of gas transmission. In water utilities, they can remotely monitor well levels and control the wells’ pumps; monitor flows, tank levels, or pressure in storage tanks; monitor water quality characteristics, such as pH, turbidity, and chlorine residual; and control the addition of chemicals. Control system functions vary from simple to complex; they can be used to simply monitor processes—for example, the environmental conditions in a small office building—or manage most activities in a municipal water system or even a nuclear power plant.

In certain industries such as chemical and power generation, safety systems are typically implemented to mitigate a disastrous event if control and other systems fail. In addition, to guard against both physical attack and system failure, organizations may establish back-up control centers that include uninterruptible power supplies and backup generators.

There are two primary types of control systems. Distributed Control Systems (DCS) typically are Supervisory Control and Data Acquisition (SCADA) systems typically are used for large, geographically dispersed distribution operations. A utility company may use a DCS to generate power and a SCADA system to distribute it.

Field devices and discreet controllers used in control systems
(Foxboro Schneider Electric).

A control system typically consists of a “master” or central supervisory control and monitoring station consisting of one or more human-machine interfaces where an operator can view status information about the remote sites and issue commands directly to the system. Typically, this station is located at a main site along with application servers and an engineering workstation that is used to configure and troubleshoot the other control system components. The supervisory control and monitoring station is typically connected to local controller stations through a hard- wired network or to remote controller stations through a communications network—which could be the Internet, a public switched telephone network, or a cable or wireless (e.g. radio, microwave, or Wi-Fi) network. Each controller station has a Remote Terminal Unit (RTU), a Programmable Logic Controller (PLC), DCS controller, or other controller that communicates with the supervisory control and monitoring station. The controller stations also include sensors and control equipment that connect directly with the working components of the infrastructure—for example, pipelines, water towers, and power lines. The sensor takes readings from the infrastructure equipment—such as water or pressure levels, electrical voltage or current—and sends a message to the controller. The controller may be programmed to determine a course of action and send a message to the control equipment instructing it what to do—for example, to turn off a valve or dispense a chemical. If the controller is not programmed to determine a course of action, the controller communicates with the supervisory control and monitoring station before sending a command back to the control equipment. The control system also can be programmed to issue alarms back to the operator when certain conditions are detected. Handheld devices, such as personal digital assistants, can be used to locally monitor controller stations. Experts report that technologies in controller stations are becoming more intelligent and automated and communicate with the supervisory central monitoring and control station less frequently, requiring less human intervention.

Swanson Flo can help you with control system questions or challenges. Reach them by calling 800-288-7926 or visiting https://swansonflo.com.

Foxboro Magnetic Flowmeter for Chemical and Process Industries

Based on Faraday’s law of induction, Foxboro magnetic meters are a reliable  ow measurement solution with a lower cost of ownership and maintenance, as well as  eld-proven stability to maximize the availability of  ow measurement.

With a wide range of liners and electrodes, the 9700A  owtube is ideal for the Chemical and Process industries. In combination with the IMT30A, IMT31A and IMT33A transmitters, Foxboro offers an innovative solution designed to meet the demands for all chemical applications such as:

• Clean liquids
• Mixing of chemicals
• Demanding applications including corrosive, abrasive liquids • Rapid variation of the pH value
• For slurries and pastes with high solids content
• Drilling applications, mining slurries with large particles

See the embedded brochure below, or download your own PDF from this Swanson Flo link.

Foxboro Magnetic Flowmeter for Chemical and Process Industries from Swanson Flo

Butterfly Valves Used in Industrial and Commercial Applications

Automated butterfly control valve.
(Valtek)

Industrial process control valves are available in uncountable combinations of materials, types, and configurations. An initial step of the selection procedure for a valve application should be choosing the valve type, thus narrowing the selection field to a more manageable level. Valve "types" can generally be classified by the closing mechanism of the valve.

A butterfly valve is used for stopping or controlling flow of liquids or materials through pipes. The "butterfly" refers to the round, flat disk that allows for flow through the valve. Butterfly valves are a member of the "quarter-turn" valve family, meaning fully open to fully closed in 90 degrees rotation. They are opened and closed via a lever, manual gear operator, pneumatic actuator, or electric actuator. Butterfly valves can be used for on-off service and some varieties are used as control valves. Butterfly valves are generally less expensive than other high flow valves, lighter in weight, and take up less piping length. Since the disk is always in the flow path, butterfly valves always have a pressure drop across the valve.

There are two primary types of butterfly classifications:

1. So called "rubber lined" butterfly valves (resilient seated) which are best suited for lower pressure, lower temperature, general purpose applications.
2. High Performance Butterfly Valves (HPBV) which are designed to ANSI pressure classifications and are suited for more robust industrial applications.

Rubber lined butterfly valve.
(Centerline)

Rubber lined (resilient seated) butterfly valves come in a variety of seating materials, where the disk "jams" in to the seat. This provides a tight closure, but also causes wear on the seat. Seat replacement is part of normal maintenance on these valves. Another characteristic of rubber lined butterfly valves are higher starting and ending torques due to the "jamming" and "unjamming" of the disk in the seat.

High performance butterfly valves have precision machined teflon, or metal seats, and are slightly offset as to lessen the amount of seat-to-disk interference. The disc still is pushed against he seat, but in a much more controlled and measured manner. Seat wear is still an issue, but not like rubber lined valves. Seating and unseating torque effects are much less as well.

Triple offset butterfly.
(Valtek)

A variation of the HPBV is the triple eccentric butterfly valve which uses a metal seat and a "triple-offset" design, best described as the disk coming "off and away" from the seat. This assures that the disk only contacts the seat at time of full closure, reducing wear on the metal seat. These valves provide excellent shut off in critical applications.

Butterfly valves come in three body styles:

1. Wafer body, whereby the valve is "sandwiched" and held in place between two pipe flanges and are suitable for lower pressure applications.
2. Lug style bodies that have threaded "lugs" cast in to the body of the valve and bolts are used to secure the valve for end of line service or keeping the valve in place when the piping is disassembled.
3. ASME flanged butterfly valves where the valve body is in-between two ASME flanges.

Butterfly valves, like other valve types, have applications where selection and design of one style outperforms another style. Careful consideration and consultation with a valve expert is a first step toward making a good selection. Combine your process know-how with the product application expertise of a professional sales engineer to produce the best solutions to your process control challenges.

Flowserve Valtek MaxFlo 4 Eccentric Rotary Plug Control Valve

The Flowserve Valtek MaxFlo 4 control valve is a high performance eccentric rotary plug valve designed for the process industry. It features a large capacity, standard hardened trim and superior shaft blow-out protection.

This valve is available in sizes 1 through 12 inches, ASME Class 150, 300 and 600 as well as DIN PN 10, PN16, PN 25, PN40 and PN63. An optional ISA 75.08.01 or DIN EN 558 series 1 long-pattern body makes this valve an easy drop-in replacement for a globe control valve. 

Founded in 1960, Swanson Flo has long maintained our position as an industry leader in process automation with unmatched project success leveraging industry preferred products and services. 

https://www.swansonflo.com 

800-288-7926

Worm Gear Valve Operators

Worm gear operator (WedgeRock)

Every industrial valve needs a means to open and close, allowing the process to flow.  Worm gear actuators provide a mechanical advantage to make hand operation possible for most quarter-turn butterfly, ball, and plug valves as well as quarter-turn and multi-turn dampers. Gears provide mechanical advantage to an operator providing the force required to open and close the valve.  Torque can be increased or decreased by changing the size of the hand wheel. Manual worm gear operators are relatively inexpensive and require little involvement beyond their in the process line.

Download the WedgeRock RW Series IOM PDF here.

WedgeRock RW Worm Gear Actuator IOM from Swanson Flo

Understanding Biofuels

Ethanol Plant

Unlike other renewable energy sources, biomass can be converted directly into liquid fuels, called "biofuels," to help meet transportation fuel needs. The two most common types of biofuels in use today are ethanol and biodiesel. Ethanol is an alcohol, the same as in beer and wine (although ethanol used as a fuel is modified to make it undrinkable). It is most commonly made by fermenting any biomass high in carbohydrates through a process similar to beer brewing. Today, ethanol is made from starches and sugars, but scientists are developing technology to allow it to be made from cellulose and hemicellulose, the fibrous material that makes up the bulk of most plant matter.

Ethanol can also be produced by a process called gasification. Gasification systems use high temperatures and a low-oxygen environment to convert biomass into synthesis gas, a mixture of hydrogen and carbon monoxide. The synthesis gas, or "syngas," can then be chemically converted into ethanol and other fuels.

Ethanol is mostly used as blending agent with gasoline to increase octane and cut down carbon monoxide and other smog-causing emissions. Some vehicles, called Flexible Fuel Vehicles, are designed to run on E85, an alternative fuel with much higher ethanol content than regular gasoline.

Biodiesel is made by combining alcohol (usually methanol) with vegetable oil, animal fat, or recycled cooking grease. It can be used as an additive (typically 20%) to reduce vehicle emissions or in its pure form as a renewable alternative fuel for diesel engines. Research into the production of liquid transportation fuels from microscopic algae, or microalgae, is reemerging. These microorganisms use the sun's energy to combine carbon dioxide with water to create biomass more efficiently and rapidly than terrestrial plants. Oil-rich microalgae strains are capable of producing the feedstock for a number of transportation fuels—biodiesel, "green" diesel and gasoline, and jet fuel—while mitigating the effects of carbon dioxide released from sources such as power plants.

Swanson Flo, and its subsidiary BioFuels Automation, has decades of experience in the renewable fuels industry. Their team is responsible for the products in over 90% of plants nationwide and are uniquely positioned to keep the existing bio-refineries operational while minimizing downtime. For more information about the processing of renewable fuels, contact Swanson Flo by calling 800-288-7926 or visiting https://www.swansonflo.com.

Happy New Year from Swanson Flo

With 2017 coming to a close, all of us at Swanson Flo wanted to reach out and send our best wishes to our customers, our vendors, and our friends! We hope that 2018 holds success and good fortune for all of you.