What Are Industrial Control Systems?

Control systems
Control system diagram (click for larger view).
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.

Control systems
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.

Control systemsA 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.

Contact Ives Equipment with any control systems question of challenge. Reach them by calling (877) 768-1600 or by visiting https://ivesequipment.com.

Alfa Laval Hygienic Liquid/Liquid Gasketed Plate and Frame Heat Exchanger

The following video illustrates the working principle of an Alfa Laval liquid/liquid 1-pass gasketed plate-and frame heat exchanger for use in hygienic applications. The hot liquid (shown in red) typically enters through one of the top connections and leaves through a lower connection. The cold liquid (shown in blue) enters through one of the bottom connections and leaves through the connection on top. Heat is transferred from the hot media to the cold media as the fluids pass through the heat exchanger.

The fluids enter the heat transfer plates through the connections and portholes. Highly engineered sealing gaskets between the plates direct the fluids so that the hot and cold fluids pass counter-currently in alternating channels. When the fluid enters between the plates, it passes over the distribution area.  Alfa Laval’s unique design distribution area is one of the most important features of a plate heat exchanger as it ensures an even flow of fluid over the entire plate, maximizes heat transfer efficiency, and minimizes maldistribution and fouling.

Note in the video the distribution area helps the fluids quickly fill up the entire cross section of the plates.

For very heat sensitive media, co-current flow is used in gasketed plate-and-frame heat exchangers allowing the coldest fluid meets the hottest fluid when entering the heat exchanger. This minimizes the risk of overheating or freezing sensitive media. Watching the video, imagine that the hot fluid is reversed, so that both fluids are entering at the bottom connections.

Alfa Laval has an extremely broad range of gasketed plate-and-frame heat exchangers which are used in all types of industries.

For more information about heat exchanger for use in hygienic applications contact Ives Equipment by calling (877) 768-1600 or by visiting https://www.ivesequipment.com.

Basic Information for the Design and Selection of Heat Trace Products for Pipe and Vessel Heating

Heat Tracing
Heat Tracing Self-Regulating Cable
To specify components for an effectively designed, totally electric heat trace system, it is necessary to understand the basic principles involved. A heat trace system is designed to replace heat lost through the thermal insulation from equipment in the system. In some applications, heat tracing will also be able to provide enough heat to significantly change the process temperature. 

It is always recommended to use thermal insulation since heat loss from bare surfaces is very high and heat transfer between the heater and the pipe/vessel is highly variable. All insulation should be weatherproofed. Wet insulation is ineffectual and heater output is insufficient to dry it.

There are several distinctively different types of electric heaters - self regulating, constant wattage, mineral insulated and tank heating panels. Each type has its own characteristics, often making one more suitable for a certain application than the others.


Self Regulating Heater Cable
Self Regulating Heater Cable will adjust its own output in response to pipe temperature. Available in a variety of temperature and power ratings up to 230°C (450°F) and 65.6w/m (20w/ft.). Product features include:
  • Variable Output
    • Self-Regulating heaters will react to variations in temperature encountered at every point along its length. Colder sections receive more heat output, while warmer sections receive less. This provides greater energy efficiency and more uniform pipe temperatures.
  • Can Be Overlapped Without Damage
    • Because Self-Regulating heaters controls its own output, overlapped sections produce less heat, eliminating “hot spots” and possible burn-through common with other types of cable.
  • Fail Safe
    • Upon reaching the upper limits of its temperature range, Self-Regulating heaters diminishes its own heat output to an insignificant level. This guarantees that maximum temperatures (T ratings) cannot be exceeded no matter what product is used in any application.
  • Easy Installation
    • Because of its infinite parallel path circuitry, Self-Regulating heaters can be cut to any length in the field without affecting the heat output or creating “dead zones”.
Constant-Wattage Heater Cable
Constant Wattage Heat Tracing
Constant Wattage Heat Tracing Cable

Constant Wattage Heater Cable is a parallel resistance heater that produces the same watts-per-foot of heat along its entire length.
  • EasyInstallation
    • Constant-Wattage heaters can be cut to length and terminated in the field. 
  • Economical 
    • Provides good power densities and exposure temperatures with parallel circuit cable capabilities at economical prices. Exposure Temperatures to +204°C (+400°F). Ideal for maintaining many process temperature applications. 
Mineral Insulated Heater Cable
MI Cable
MI Cable

Mineral insulated Cable is a series conductor, high temperature heater cable with a special, thin metal sheath. Some of MI advantages are:
  • Corrosion-Resistant
    • Alloy 825 sheath provides excellent corrosion resistance and immunity from chloride stress corrosion - a common problem with stainless steel. 
  • Ideal for High Temperature Applications
    • Mineral Insulated heaters can withstand exposure temperatures up to 593°C (1100°F). Exposure temperatures can be increased to 750°C (1400°F) with special components. 
  • Ratings To 600V
    • Mineral Insulated heaters are available in a variety of voltages to match the available power supply. 
  • High Heat Output 
    • Mineral Insulated heaters have heat output ratings up to 10 times higher than most other cables, reducing the amount of cable required. 
  • Rugged Construction
    • A durable metal sheath provides greater mechanical protection.
  • Thin Wall Construction
    • A unique manufacturing process allows thin wall cable construction for easier field installation. 
Tank Heating Panels
Heating Panel
Heating Panel

  • Low Cost Installation
    • Flexible silicone construction allows panel to conform to tank wall. No bonding or heat transfer aids are required. 
  • High Temperature 
    • Tank Heating Panels maintain temperatures up to 79°C (175°F) and can withstand exposure to 204°C (400°F).