Ultra-Low ΔP Mass Flow Controller - SmartTrak® 140

Get Incredible 4.5 psid (310 mBard) at Flows up to 500 slpm

When you need precision gas mass flow control of expensive process gases, where minimal pressure drop is a key consideration for cost savings and efficiency, the SmartTrak® 140 controls up to 500 slpm with an ultra-low ΔP of 4.5 psid (310 mBard) much better than typical ΔP values of 25 psid (1700 mBard) for equivalent mass flow controllers on the market.

  • Control up to 500 slpm (nlpm) with 4.5 psid (310 mBard)
  • High accuracy (+/- 1.0 % of full scale)
  • Highly repeatable (+/- 0.2% of full scale)
  • True linear performance (+/- 1.0 % of full scale in 10 standard gases)
  • 10 different gases using Dial-A-Gas® Technology
 SmartTrak® 140 Ultra-Low ΔP Mass Flow Controller

SmartTrak® 140 Ultra-Low ΔP Mass Flow Controller




Technical Details

  • Control up to 500 slpm (nlpm) with 4.5 psid (310 mBard)
  • High accuracy (+/- 1.0 % of full scale)
  • Highly repeatable (+/- 0.2% of full scale)
  • True linear performance (+/- 1.0 % of full scale in 10 standard gases)
  • 10 different gases using Dial-A-Gas® Technology
  • Precision digital PID valve control;no valve tuning or adjustment
  • Control valve with large flow coefficient (Cv) for precise control at low ΔP
  • Patented, inherently linear Laminar Flow Element (LFE)
  • Advanced platinum sensor technology
  • All 316 stainless steel construction
  • Unique Pilot Module (mounted or hand-held) allows these control functions
  • Avoid recalibration by re-zeroing and re-spanning in the field
  • Multiple outputs (both analog and digital)
  • Primary standard calibration, NIST-traceable certification
  • Digital communications solutions include: Foundation Fieldbus, Modbus RTU, and Profibus DP.
  • Add Compod for enhanced Modbus networking, digital relays, analog input, and pulse output

Product Information

When you need precision gas mass flow control of expensive process gases, where minimal pressure drop is a key consideration for cost savings and efficiency, the SmartTrak® 140 controls up to 500 slpm with an ultra-low ΔP of 4.5 psid (310 mBard) much better than typical ΔP values of 25 psid (1700 mBard) for equivalent mass flow controllers on the market.

Sierra’s digital communications solutions offer engineers and systems integrators, full system integration and networking capability with Sierra's mass flow control systems. Digital communications solutions include: Foundation Fieldbus, Modbus RTU, and Profibus DP. For enhanced networking capability, including two digital relays, totalization, inputs, and display, add the Compod Control Module™ to easily program a wide veriety of common flow systems and process controls ranging from gas mixing and dilution to leak testing.


Operating Principle

The Capillary Thermal Operating Principle

The principles of capillary thermal mass flow controller technology operation. See how the molecule of gas travels through the pipe and instrument allowing for accurate mass flow control and measurement. Based on heat transfer and the first law of thermodynamics, capillary thermal mass flow controllers enable accurate and repeatable gas mass flow measurement and control.

The operating principle of the SmartTrak instruments is based on heat transfer and the first law of thermodynamics. During operation process gas enters the instrument’s flow body and divides into two flow paths, one through the sensor tube, and the other through the laminar flow bypass. The laminar flow bypass (often called LFE which stands for “laminar flow element”) generates a pressure drop, P1–P2, forcing a small fraction of the total flow to pass through the sensor tube (m1).

Two resistance temperature detector (RTD) coils around the sensor tube direct a constant amount of heat (H) into the gas stream. During operation, the gas mass flow carries heat from the upstream coil to the downstream coil. The resulting temperature difference (∆T) is measured by the SmartTrak microprocessor. From this, SmartTrak calculates the output signal. Since the molecules of the gas carry away the heat, the output signal is linearly proportional to gas mass flow.

Figures 1-2 and 1-3 show the mass flow through the sensor tube as inversely proportional to the temperature difference of the coils. The coils are legs of a bridge circuit with an output voltage in direct proportion to the difference in the coils’ resistance; the result is the temperature difference (∆T). Two other parameters, heat input (H) and coefficient of specific heat (Cp) are both constant. Through careful design and attention to these parameters, this output signal is made linear over the transducer’s normal operating range (Figure 1-4). As a result, the measured flow through the sensor tube is directly proportional to the gas flow in the main body.

In the SmartTrak mass flow controllers, the gas which flows through the monitoring section is precisely regulated by the built-in electromagnetic valve. The normally closed valve is similar to an on/off solenoid valve, except that the current to the valve coil, and hence the magnetic field, is modulated so that the ferromagnetic valve armature, or valve plug, assumes the exact height above the valve’s orifice required to maintain the valve’s command flow (set point). The result is excellent resolution.