The Role of Modulating Valves in Industrial Combustion

The Role of Modulating Valves in Industrial Combustion

In industrial combustion systems, burners are used to generate heat by burning a fuel and air mixture. The burners are typically controlled by modulating valves, which regulate the flow of fuel and air to the burner.

Modulating valves are used to adjust the flow of fuel and air to the burner in order to maintain a stable and consistent flame. They are typically used in conjunction with a temperature control system, which measures the temperature of the process and sends a signal to the modulating valve to adjust the flow of fuel and air as needed to maintain the desired temperature.

There are several types of modulating valves that can be used for burner control, including pneumatic valves, electric valves, and hydraulic valves. Each type has its own advantages and disadvantages, and the most appropriate type of valve for a given application will depend on factors such as the type of fuel being burned, the type of burner system, and the operating conditions of the process.

In addition to their primary function of controlling the flow of fuel and air to the burner, modulating valves can also be used to shut off the flow of fuel and air in the event of an emergency or to perform maintenance on the burner system. They are an essential component of any industrial combustion system and play a critical role in ensuring the safe and efficient operation of the system.

Combustion Technology, LLC

Surplus Inventory Listing Added to Combustion Technology Website

Surplus Inventory Listing Added to Combustion Technology Website

For over three decades, Combustion Technology has supplied combustion and process heating equipment, specifically temperature controls, thermocouples, gas pressure regulators, flowmeters, and industrial burner systems and packages. 

Combustion Technology recently added a section to their website listing surplus inventory. This surplus consists of overstocked items, unused returns, and obsolete items. Right now, the list is small but will grow over time. Make sure you check back frequently. 

If you're in the combustion system service and repair business, this will be a resource for hard-to-find or obsolete combustion parts.

For more information, call 800-327-1831 or visit

Experts in Industrial Combustion Airflow Management

Experts in Industrial Combustion Airflow Management

To enhance efficiency and achieve optimal process performance, boilers, furnaces, regenerative thermal oxidizers (RTOs), and burners must be calibrated with an optimal air-to-fuel ratio. Measuring airflow is critical to determining this ratio and optimizing combustion. Over time, an efficient system will also result in lower maintenance expenses. 

Contact Combustion Technology with Your Natural Gas Fired Industrial Boilers and Package Boilers Applications

Even though natural gas processes tend to burn cleaner than other fuel types, these boilers nonetheless confront particulate-laden airflows. They may be subject to emissions rules if discharged into the atmosphere. These boilers frequently lack precise instrumentation for measuring air and natural gas combustion flow to optimize the air-to-fuel ratio. We can help.

Assistance with Your Power, Biomass, and Recovery Boiler Needs

Whatever the fuel may be, measuring the airflow into the boiler combustion chamber is required to calculate the ideal air-to-fuel ratio. An either too lean or too rich system causes performance or cost difficulties. Emissions problems occur due to faulty burner design or inefficient combustion in boilers. Stop dealing with underperforming boilers and repair underperforming combustion using an air measurement system.

Decades of Experience with Heaters, Furnaces, Ovens, and Kilns

The industrial sector relies on heat from a range of supplied burner equipment to conduct critical process operations, whether for ceramics and glass or annealing and debinding. Fuel prices might be prohibitively high in some procedures requiring extremely high temperatures. Using airflow measurement devices to optimize combustion will save operating costs by increasing efficiencies and improving emissions. Plant managers rely on Combustion Technology's professional application engineers to find the best solutions for improving combustion process efficiency.

Combustion Technology, LLC

Wiring the Siemens Combustion Controls SQM4 Synchro for 4-20 mA Modulation

This video explains the simple wiring of the most common SQM4 Synchro actuator from Siemens Combustion Controls.  The "5" board (SQM4x.x5x...) is used with a 4-20mA signal and offers a fantastic alternative to outdated MODulating actuators.

The Siemens SQM4 Synchro is a cost effective modulating actuator with up to 160 in-lbs and 12 or 25 second drive times for 90 degrees. The SQM4 Synchro is suited for driving oil pressure controller, butterfly valves, dampers or for use on other applications that require rotary motion.


  • NEMA 4 – No need for weather shields
  • No restrictions on mounting orientation – No more elaborate linkages to keep the shaft horizontal!
  • The modulating input versions accept 2-10 Vdc, 4-20 mA or 0-135 ohm control signals
Areas of application are oil and gas burners of medium to higher capacity as well as
thermal process plants.

For more information contact Combustion Tech. Call 800-327-1831 or visit

Combustion Technology Distributes Pietro Fiorentini Gas Regulators in Pacific Northwest

Pietro Fiorentini Gas Regulators in Pacific Northwest

Pietro Fiorentini is a world-leading gas pressure regulator manufacturer of various gas-fired indoor and outdoor equipment. The company also develops technologically cutting-edge products and services for gas distribution.

Combustion Technology, Inc. is very pleased to be selected as the product line distributor in the Pacific Northwest (the states of Oregon, Washington, and Idaho).

Pietro Fiorentini product lines include:
  • GOVAL Line Pressure Regulator
  • Governor
  • Dival 600
  • Trias
  • Dival 160 AP
  • Dival 500
  • VS/AM 65
  • VS/AM 58
  • Aperval
  • SCN Slam Shut
  • Aperval 101
  • Aperflux 101
  • Governor 2 PSIG
  • Dilock Safety Device
  • Aperflux 851
  • Governor Dual Cut 10 PSIG
  • PVS 782 Slam Shut
  • Zero/Ratio GOVERNOR Regulators
  • Governor PF400 Outdoor
  • PVS 803 Slam Shut
  • Governor PF400 Vertical Vent Limiter
  • Governor PF400 Vent Limiter
  • Mod FE
  • Mod FEX
  • Norval
  • Cirval
  • Reflux 819
  • Reval 182
  • HBC 975
  • Staflux 185
  • SBC 782 Safety Device
  • Staflux MINI
For more information about Pietro Fiorentini Gas Regulators contact Combustion Technology, LLC. Call 800-327-1831 or visit

Phoenix Velocity Heat (VH) Direct Fired Burners: 500,000 up to 2,000,000 BTU/hr

Phoenix Velocity Heat (VH)

You Don’t Have to accept 6 month lead times from
other direct burner manufacturers! 

Phoenix Velocity Heat direct fired burners provide exceptional quality and excellent lead times.  From 500,00 to 2,000,000 BTU/Hr.

Highest Velocity Flame
The VH produces an intense stream of hot gases to thoroughly penetrate the load and deliver precise temperature uniformity for consistent product quality and system efficiency.

Large Turndown Combined With High Excess Air
A wide turndown range with high excess air means VH delivers high-velocity benefits and efficiencies across its operating range.

Customization With Packaged Convenience
All VH components have been pre-engineered to come together to meet your specific requirements. You choose the capacity, combustor outlet velocity, fuel type, and flame sensing components you need to do the job.

Unparalleled Fuel and Control Convenience
The VH offers the convenience of multi-fuel capability with no nozzle change. Plus, you can use any control methodology; pulse firing, excess air, or on-ratio.

For more information about Phoenix Velocity Heat Direct Fired Burners contact Combustion Technology, LLC. Call 800-327-1831 or visit

Flame Scanners and Detectors

Flame Scanners

In combustion applications, flame scanners (flame detectors) validate the existence of flame in many hazardous environments and applications, such as hydrogen stations, industrial heating systems, drying systems, industrial gas turbines, combustion chambers, and industrial flares. Their use is critical to ensure that any fuel entering combustion equipment is consumed and not accumulating unburned, presenting a safety hazard.

Unique flame features distinguish the types of flames produced by various burners and compounds. Proper flame detection requires knowledge of the flame itself, its emissive properties, and other features. Apart from temperature, flame scanners and detectors often use radiation and the production of ionized gas molecules to detect the presence of the flame. 

Modern scanners detect the presence or absence of flames that emit ultraviolet radiation (UV). Typical fossil fuels which emit UV include natural gas, propane, methane, butane, kerosene, light petroleum distillates, and diesel fuels. For burners firing steam-atomized oil or pulverized coal, use infrared (IR) scanners. In some situations, specific photoelectric detectors may detect a distinctive flicker in any flame invisible to the naked eye. 

For over three decades, Combustion Technology has applied flame scanning and detection solutions and equipment for process heating applications. Call them with any flame detection requirement.

The Siemens Combustion Controls LFS1 Flame Detection Switch

The Siemens LFS1 flame switch works in conjunction with a PLC. When the PLC operates as the combustion safeguard, it powers the shutdown valves, perform burner sequencing, monitors interlocks, and controls purging. The LFS1 flame switch communicates the existence of a flame to the PLC through a contact closure. The LFS1's small form conserves valuable panel space.

Flame safeguards have many names. We'll oversimplify and group all of these names to make a point. These names imply a stand-alone device detecting flame, energizing the shutoff valves, monitoring interlocks, and conducting purge. A flame switch is simply a contact. The contact closes when a flame is present and opens when a flame is not present. This opening and closing of the contact let the PLC know the presence of the flame. That's it. The sequencing, powering of the shutoff valves, monitoring, and conducting purge are all done in the PLC. The heart of the flame switch is the FR1 contact closing between terminals 11 and 12. The contact is normally open and closes upon the presence of the flame. The LFS1 takes on the liability of proving the presence of the flame, so the PLC doesn't have to. HR1 contact is an auxiliary contact used for other Siemens products. For a PLC application, SCC instructs to keep the power on terminal 6, resulting in HR1 being closed all the time. 

NFPA 86 has criteria for the PLC to be combustion safety. Combustion safety here means the sequencing, powering shutoff valves, and conducting purge. There are two avenues for the PLCs to be the combustion safety: 1) listed for combustion service and 2) not listed for combustion service. The listed PLC is straightforward and designed for combustion safety. The non-listed PLC to be used for combustion safety must meet the criteria of section 8.4.2 in NFPA 86. Third-party certified SIL-2 and restricted access are a few of the requirements for a non-listed PLC. If the PLC is the combustion safety, all you need is the LFS1 flame switch. 

Panel space is premium. The LFS1 flame switch is a compact device being 3.5 inches wide and 2.5 inches tall. The small footprint saves on space, especially for multi-burner applications. A mounting base goes with the LFS1, making it 2.5 inches deep. 

The LFS1 can report the flame signal strength via a 0-10VDC output, making it helpful to display flame signal strength for the service technician or the operator. The LFS1 can condition the relationship between the microamp flame signal and the 0 to 10VDC signal.

The LFS1 has global approvals, most recently North American approvals of UL, FM, and CSA. The LFS1 is also SIL-3 capable.

For more information about Siemens Combustion Control products in the Pacific Northwest, contact Combustion Technology, LLC. Call 800-327-1831 or visit

Indirect Fired Process Air Heater for Raising Ambient Temperatures to the Desired Process Air Requirements - The Selas HEM

Indirect Fired Process Air Heater

The Selas HEM Indirect Fired Process Air Heater - Designed to fire applications where process air needs to be heated from ambient temperatures to the process plant’s heat requirements.

Selas HEM Indirect Fired Process Air Heater Operating Principles 

Burner Assemblies
Each HEM unit is supplied with a pre-packaged and pre-wired burner assembly which includes all of the necessary burner fuel safety valves, pressure switches and automatic ignition and flame safety equipment. Most types of flame failure and automatic ignition control units can be supplied, utilizing flame rectification, photo cell or ultra-violet flame sensing equipment. Air heating burners built to specific applications and country of installation can be fitted. All Burner packages are fully tested and the operation of all components are checked before dispatch from the factory.

Fuel Supply
Burners can be fitted for operation with natural gas, LP gases or light fuel oils. All gas burners are sized to suit an inlet gas pressure of 17.5mbar (natural gas) or 30mbar (LP gases) unless otherwise specified. Burners can be supplied to suit other fuel types and supply pressures.

Direction of Air Flow
Standard HEM process air heaters are arranged to fire horizontally in the direction of air flow from left to right. Heater units can be supplied for firing into duct systems with vertical upwards or downwards air flow. Air flow should be uniform across the air duct, both upstream and downstream of the heater.

Electrical Supply
The HEM units can be fitted with burners to suit almost all types of electrical supply, including all common industrial three phase (50 or 60Hz) power supplies. Burners can be supplied to accommodate electrical voltages for specific applications and destinations.

  • Fully modulating, indirect firing burner
  • Pre-packaged and pre-wired burner assembly
  • High temp limit thermostat or thermocouple unit
  • High-grade stainless steel combustion chamber
  • Operates on natural gas, LP or light fuel oil
  • Ideal for shopping centers & commercial premises
  • Ready for drop-in installation
  • Protects the heat exchanger from overheat
  • Durable construction for long life
  • Installation not dependent on single fuel source
For more information about Selas products in the Pacific Northwest, contact Combustion Technology, LLC. Call 800-327-1831 or visit

Process Heating and Control for Hemp Drying and Hemp Oil Processing

Process Heating and Control for Hemp Drying and Hemp Oil Processing

Hemp is experiencing a renaissance in popularity due to increased demand for CBD oil and commercial items such as paper, textiles, clothing, biodegradable plastics, paint, insulation, biofuel, food, and animal feed. By 2025, the global industrial hemp market could be worth more than $10 billion. 

Hemp was legalized as part of the 2018 Farm Bill, transforming it from a controlled substance to an agricultural commodity. Farmers whose tariff increases have impacted certain crops find hemp cultivation appealing. Consumer demand, combined with higher farm profits, is driving explosive growth. Hemp cultivation occurs for seed, fiber, or floral biomass. 

After harvest, the hemp needs to be immediately transported to a drying facility to remove the moisture content. Hemp harvesting and drying are critical steps in CBD production. Molds and mildews associated with moisture reduce the value of floral hemp biomass, so the harvest needs stabilization before mold, mildew, or decomposition can occur. 

Air drying small batches of hemp in a barn makes sense despite its inefficiency and slowness, but more modern and systematic approaches to drying are required to meet consumer demand for large batches. New industrial dryers with capacities ranging from 1000 to 4000 pounds of biomass per hour and total drying control are available to meet this skyrocketing demand. 

Batch dryers have drying chambers that typically include a dehumidifier, an aerator, and a heat source. The energy-efficient dehydration systems for drying hemp are closed systems that operate independently of ambient conditions. Combining the heat-driven dehumidification unit, a programmable controller, and airflow equipment result in consistent drying conditions inside the chamber. 

Belt dryers include a conveyor that leads into a large drying chamber. Mesh-belt hemp dryers continuously dry large quantities of biomass in a short time without requiring a large production footprint. Belt dryers enable an operator to fine-tune the hemp dryer's thermal energy to evaporate moisture without over-drying or overheating the hemp. Belt dryers use propane or natural gas as their heat source with high BTU output. Belt dryers also use electronic controls for precise biomass drying and optimize combustion efficiency. 

Rotary dryers have been the workhorse of industrial dryers for many years. They also work well for drying hemp and typically use natural gas as their heat source. The biomass goes in a heated cylinder, which rotates and tumbles the material in the presence of hot, dry air. Plates on the inside of the cylinder, or drum, move the hemp through the drum, and sophisticated electronic combustion controls regulate temperature and time for the drying process.

Legacy custom oven and furnace manufacturers are finding a new, lucrative market for hemp dryers and hemp oil processing, considering the technology and fabrication process are nearly identical to the custom furnace and kiln development. Burners, controls, and gas valves are all standard components. A critical piece for success in developing a successful hemp drying strategy is to work closely with an expert in process heating, combustion, and control systems. Their breadth of experience and engineering skills will contribute to positive outcomes.

For expert advice on process heating and control systems specifically for hemp oil processing and hemp drying, contact Combustion Technology, LLC. Their experience in combustion optimization, thermal profiling, and temperature measurement is premier. They have equipment and instrumentation ready to provide the high-level performance required for the hemp processing industry, such as:

  • Wide turndown burners with precise temperature control. 
  • Modulating gas control valves with .1 of a degree positioning accuracy. 
  • Process controllers and indicators are accurate to .25% of span.
  • 508A listed electrical panels, NFPA 86 compliant
  • Secure digital recording of temperature and other critical variables for contract drying.

Headquartered in the Pacific Northwest, reach them by calling 800-327-1831 or visiting their website at