The Siemens Combustion Controls SQM4 Synchro Modulating Actuator

The SQM40/SQM41 actuators are suited for driving oil pressure controller, butterfly valves, dampers or for use on other applications that require rotary motion.

The actuators are used primarily for load-dependent control of the flow of gas, oil and combustion air in connection with modulating 3-position controllers or continuous controllers (4-20 mA) and/or directly by burner controls.

The Siemens SQM4 series actuator is great for modulating air and fuel valves. it can also be mounted to a linkage for multiple control points. the resolution on this on this actuator is over 100 steps. this resolution is three times the leading competitor. this resolution is helpful to hone in on the desired set point with precision, rather than hunting or oscillating. this actuator comes in three torque settings: 45 inch pounds; 90 inch pounds; or 160 inch pounds. this actuator is NEMA 4. there is a gasket around the cover and the shaft is sealed to make it entirely NEMA 4. high fire and low fire conditions are simply set by turning these cams. 

The SCC SQM4 actuator has low voltage terminals and high voltage terminals. the low voltage is helpful for analog signals such as 4-20 mA, 0-135 ohm, and 2-10 volt DC. the high voltage terminals are for your line voltages for the actuator to modulate according to the analog signal voltage. 

The SQM4 series actuator is in stock for a common lead time of one to two days. this actuator can be direct coupled to a control valve for air or fuel control, or we also with couplings, crank arms and brackets to mount the actuator for your needs. 

Areas of application are oil and gas burners of medium to higher capacity as well as thermal process plants.

For more information in the Pacific Northwest, contact Combustion Technology. Call them at 800-327-1831 or visit their website at

The Pacific Northwest's Leading Process Heating and Combustion Equipment Supplier


Process Heating and Combustion Equipment Supplier

A Complete Portfolio of Process Heating and Combustion Services & Solutions

  • Apply Process Heating Equipment & Combustion Components
  • Engineer Systems
  • Regulatory Safety Audits
  • Troubleshoot Combustion Equipment
  • Provide Upgrades & Repairs
  • Provide Maintenance Agreements
  • Combustion Efficiency Audits
  • UL 508 Control Panels

Let COMBUSTION TECHNOLOGY help design your next industrial heating and control system using their 30+ years of experience and knowledge.

COMBUSTION TECHNOLOGY is a recognized leader in the Pacific Northwest, providing process heating and combustion solutions, field service, startup, and calibration services.



Now Through June 25 - Huge Savings for Fireye Flame Scanners with SureFire II Spark Igniters

Savings for Fireye Flame Scanners

Save 25% when you bundle any Flame Scanner with SureFire II Spark Igniters now through June 25, 2021.

Contact Combustion Technology for more information.

Combustion Technology, LLC

Azbil's AX24R Multivariable Reduced Bore Vortex Flowmeter

AX24R Multivariable Reduced Bore Vortex Flowmeter

Azbil’s AX24R Multivariable Vortex Flowmeter offers accurate and reliable flow metering in a multivariable design. The multivariable design incorporates a high-accuracy velocity sensor, a precision platinum RTD temperature sensor, and a solid-state pressure transducer. The meter’s process connections match the line size but use integrated reducing flanges, and the meter body reduces in diameter, increasing the fluid velocity through the meter. Increasing the velocity in this fashion extends the meter’s measuring range to capture lower flow rates that a full line size meter might miss.


Combustion Technology, LLC

The Siemens SKP25 Combination Safety Shutoff Valve and Regulator

The Siemens SKP25 controls the burner manifold gas pressure according to a fixed setpoint. The SKP25 can also be applied as a 1:1 air/gas proportionator or zero governor. 

  • Safety shut‐off function and pressure regulating function in one compact unit.
  • Applicable as 1:1 air/gas proportionator or zero governor.
  • Accurate pressure control characteristics, and zero offset (drop).
  • Integral regulation leak limiter.
  • Excellent tracking characteristic

Combustion Technology, LLC

Understanding the Importance of Pressure Drop When Using Flowmeters

Pressure Drop

The pressure inside a pipe can vary from the pressure outside of the process. Friction or a physical obstruction in the pipe may cause a pressure drop in the system, resulting in a loss of line pressure.

Figure 1 shows a high and robust pressure reading at point "A," followed by the pipe narrowing. The pressure reading then drops at point "B." This phenomenon is the definition of pressure drop. 

Pressure Drop

Figure 1: Visual example of a pressure drop in a pipe where a narrowing of the pipe causes a drop in

pressure from point “A” to point “B”.

Maintaining pressure can be vital to the device's operation, its equipment components, or the process performance.

Pressure Drop Rates and Gas Flow Technologies 

There are several flow measurement technologies available on the market today. Each technology uses a different method to measure a pipe flow rate, but some are known to cause undesirable pressure drops. It is unrecoverable once the pressure decreases. Let's look at some of the most popular flow measurement technologies and their pressure drop scores.

Thermal Mass Flow Meters Have a Negligible Pressure Drop 

Pressure drop compare
Thermal mass flow meters calculate the direct mass flow of air and gases in volumetric or mass units. The fact that the pressure drop in the pipe is negligible or very low is a significant advantage of thermal mass flow technology. There are no moving parts to disrupt the flow, and no additional pressure or temperature compensation is needed to measure the gas's mass flow rate.

Other Advantages of Thermal Mass Flow Measuring 

There are many advantages of using thermal gas mass flow meters over other flow measurement technologies: 

  • Air and gas mass flow measurements in standard volumetric units (e.g., SCFM or NM3/H) or mass units (e.g., LBS/M or KG/H) 
  • There is no need for extra pressure or temperature compensation. 
  • Repeatability and an extremely wide measurement range: up to 1000:1 (100:1 typical) 
  • 4-20mA linear output proportional to mass flow rate 
  • There are no moving parts. 
  • Insertion, Inline, and remote* models are all available. 
  • Flow rate and temperature are measured.

Fox Thermal is revolutionizing thermal mass flow measurement technology with a series of innovations: 

  • Microprocessor-based, field-rangeable electronics
  • DDC-Sensor™ proprietary flow sensor design*
  • Gas-SelectX® field selectable gases/gas mixes without affecting accuracy*
  • CAL-V™ and Zero CAL-CHECK® Calibration Validation*
  • Free FT View™ Software to configure meter, print calibration validation certificates, run simulations, and more!*
  • Data Logger with 7-year history*
*features vary by model number.

For more information in the Pacific Northwest, contact Combustion Technology. Call them at 800-327-1831 or visit their website at