CTI Controltech Industrial Combustion and Process Control Blog

Heavy Duty Scotch Yoke Pneumatic Valve Actuator

Scotch yoke refers to a sliding linear mechanism that provides a reciprocating motion. One of the most common uses for scotch yokes are pneumatic valve actuators.

Scotch yoke mechanism
(courtesy of Wikipedia)

Scotch yoke valve actuators are designed to provide higher torque output for larger industrial valves. They typically have large pistons and air cylinders that provide the linear force required to open and close large quarter turn valves (ball, butterfly, plug).

Scotch yoke pneumatic actuators installed
in sea terminal
(courtesy of Rotork)

Scotch yoke actuators can be energized by either compressed gases, or hydraulic fluids. Here are some images of scotch yoke actuators in use:

Large spring return scotch yoke actuator
(courtesy of Rotork)

Commissioning a Jerguson Glass Level Gage with Safety Ball Check Valves

Here is a how-to video, courtesy of Clark-Reliance/Jerguson on starting up a glass level gage (gauge) with safety ball check valves.

Flame Discrimination and Detection for Multi-fuel Applications

Safe, reliable infrared and ultraviolet flame discrimination and detection for multi-fuel applications.

Flame scanners are used to detect emissions from fossil fuel flames. These can be gaseous fuel, light petroleum distillates, diesel fuels, heavy fuel oils and a variety of coals. They are suited for application to multiple burner furnaces in utilities and pulp and paper plants, industrial application such as petrochemical, refinery and chemical production, through to industrial boilers. Flame temperature measurement can be used to monitor and report on many applications including specialized burners used in applications such as Low NOx, Incineration and sulfur recovery.

An Industrial Electric Actuator Designed to Keep the Water and Dust Out

The Rotork IQ3 electric actuator includes a double o-ring seal to keep the internal parts sealed away from water and dust should the electrical conduit seals fail.

The Rotork IQ3 also includes these advanced features:

New intuitive user interface
Advanced dual stacked display with configurable datalogger functionality
Toughened glass screen plus optional environmental shield
Setting tool with secured Bluetooth® connection
High reliability, solid-state controls
Reduced internal wiring and connections
Simplified torque sensor
Simple and robust absolute position sensor with high reliability and accuracy
New thrust base design
Separable gearbox/thrust base across the range
Advanced real-time status reporting

Watch this video to see the how the IQ3 double o-ring seal keeps out water and dust.

Types of Level Instruments in Process Control

Tuning fork level controls
(form of echo level sensing)

In many industrial processes, the measurement of level is critical. Depending on the nature of the material being measured, this can be a simple or complex task. Several different technologies for sensing level are briefly explained here.

Sight Glasses or Sight Gauges
A very simple type of level measurement device for direct visual measurement of level in a tank or vessel. A sight gauge is usually a clear glass or plastic tube connected to the a vessel at the top and bottom of the level range needing to be viewed. As long as interface (different fluids with different densities floating on each other) the fluid level inside the vessel will be at the same hight as the level in the tube.

Choosing an improperly applied sized or improperly sized control valve can have serious consequences on operation, productivity and most important, safety. Here is a quick checkist of basics that need to be considered:

Not an isolation valve:
Control valves are not intended for isolating a process and should not be used as such. They are not intended to provide a bubble tight shutoff.

Choose the correct materials of construction:
The valve body, seat and wetted materials must be compatible with the process being controlled. Take into consideration pressure ratings and operating temperatures along with the material compatibility prior to valve selection.

Selective Catalytic
Reduction Systems

During the combustion process in large industrial or commercial boilers, the natural nitrogen in coal combines with oxygen forming nitrogen oxides (NOx). Nitrogen oxides in the atmosphere are unacceptable because they contribute to ground level ozone and undergo reactions in the atmosphere to form unwanted, and possibly harmful, fine particles.

Selective Catalytic Reduction (SCR) is a means of converting nitrogen oxides (NOx) to harmless nitrogen, water and trace CO2 by using an advanced emissions control system that injects a liquid-reductant agent, typically anhydrous ammonia, aqueous ammonia or urea, through a catalyst into the combustion exhaust stream.

The name "selective" derives because it selectively reduces levels of nitrogen oxides and "reduction" because of the chemical reaction where the ammonia or urea is the reducing agent converts NOx to nitrogen, water and CO2.

Commercial selective catalytic reduction systems are typically found on large utility boilers, industrial boilers, and municipal solid waste boilers. They have been shown to reduce NO by 70-95%.

SCR systems are one of the most cost-effective technologies available, while delivering great efficiency, being capable of reducing NOx emissions by up to 95 percent.

For more information on SCR's (Selective Catalytic Reduction Sytems) contact CTi Combustion.