What Are 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 used within a single processing or generating plant or over a small geographic area. 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.

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-Fi4) 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.

For more information about industrial control systems, visit https://controlsystems.processcontrolsolutions.com of call (800) 462-5769.

Diaphragm Seals Protect Your Pressure Instruments, Your Plant, and Your People

Diaphragm seal (Wika)

Pressure measurement is a common element of industrial operations or control systems. Fluid processing can often involve media that is potentially harmful to pressure sensing devices. The media may be corrosive to the sensor material, or other media properties may impact the performance or usable life of the instrument. In process control environments, diaphragm seals play a role in protecting items like pressure sensors from damage by process fluids. The diaphragm seal is a flexible membrane that seals across the connecting path to a sensor and isolates the sensor from the process media. System pressure crosses the barrier without inhibition, enabling accurate measurement, but the process fluid does not. Typical materials composing diaphragm seals are elastomers, with a wide variety of specific materials available to accommodate almost every application.

In the operating principle of the diaphragm seal, the sealed chamber created between the diaphragm and the instrument is filled with an appropriate fluid, allowing for the transfer of pressure from the process media to the protected sensor. The seals are attached to the process by threaded, open flange, sanitary, or other connections. Diaphragm seals are sometimes referred to as chemical seals or gauge guards. Stainless steel, Hastelloy, Monel, Inconel, and titanium are used in high pressure environments, and some materials are known to work better when paired with certain chemicals.

Sanitary processes, such as food, beverage, and pharmaceuticals, use diaphragm seals to prevent the

Sterile, diaphragm inline seal
with temperature measurement.
(Wika)

accumulation of process fluid in pressure ports, a possible source of contamination. If such a buildup were to occur, such as milk invading and lodging in a port on a pressure gauge, the resulting contamination compromises the quality and purity of successive batches. Extremely pure process fluids, like ultra-pure water, could be contaminated by the metal surface of a process sensor. Some pneumatic systems rely on the elimination of even the smallest pressure fluctuations, and diaphragm seals prevent those by ensuring the separation of the process materials from the sensors.

Diaphragm seals are not without some application concerns, and devices are now built to address and counter many potential issues related to the use of diaphragm seals with process monitoring instruments and equipment. Products seek to eliminate any and all dead space, allow for continuous process flow, and are self-cleaning thanks to continuous flow design. Some high pressure seals come equipped with anti-clogging features, accomplished by the elimination of internal cavities while protecting gauges. Multi-purpose seals reduce temperature influence and improve instrument performance while pinpointing and diffusing areas of high stress. These pre-emptive measures result in longer instrument life-cycles and improved performance while ensuring protection from corrosion.

There are numerous options and available diaphragm seal variants. Share your application specifics with a product specialist, combining your own process knowledge and experience with their product application expertise to develop an effective solution.

Red Valve: Pinch Valves, Check Valves, Expansion Joints, Pressure Sensors

Red Valve has set the standard for solving the world’s toughest flow control challenges through unmatched elastomer design and manufacturing experience. Red Valve is dedicated to exceeding customer expectations with proven, creative, high-value solutions.

Red Valve products are designed to handle the toughest flow applications in:

• Power Plants – FGD Systems, Scrubber Systems, Coal Handling
• Mining Facilities – Tailings, Flotation Control, Thickener Underflow Lines, Numerous Other Slurry Applications
• Chemical Processes – Corrosive and Abrasive Materials, Powders, Pellets
• Pulp & Paper Mills – Sludge Handling, Grit Removal, Lime, Carbon Slurry
• Bulk Materials - Food, Cement, Sand, Glass
• Industrial Treatment Plants

Process Control Solutions
https://flowcontrol.processcontrolsolutions.com
(800) 462-5769

Valve Selection Guide for Wastewater Treatment

Wastewater Treatment Facility

Over the past 30 years, the process of wastewater treatment has seen dramatic changes as world populations continue to increase and concern over the environment grows. Ever more stringent regulations for wastewater quality have been met with high-tech engineering. Red Valve Company has worked closely with the designers and operators of wastewater treatment plants across the globe to provide innovative solutions for the most difficult challenges faced in a treatment plant.

Unlike most valve companies who view water and wastewater as one and the same, Red Valve provides products specifically engineered for the rigors of use on slurries such as sewage, sludge and grit. Red Valve provides a Total System Solution for Wastewater Treatment that encompasses every step of the treatment process, from collection to final discharge. Their commitment is to provide dependable, cost effective products that offer the best possible solution for their particular application. See the brochure below for specific water treatment facility applications where these products provide a proven, superior engineered solution.

Contact Process Control Solutions with your valve and actuation requirements by calling (800) 462-5769 or by visiting https://flowcontrol.processcontrolsolutions.com.

Red Valve Solutions Guide for Wastewater Treatment Facilities from Process Control Solutions, LLC