For Powder Processing and Handling

Model 31

Intrinsically Safe Aspirator-driven Sampler

The Model 31 Series Sample Conditioning Package uses a pneumatically-driven aspirator to extract the sample from the process.  Using compressed air or nitrogen as the drive gas, the aspirator produces vacuum by means of the Venturi effect.  This vacuum is used to draw the sample gas from a long distance without long lag times in sensor response.  With no moving parts, the aspirator is intrinsically safe.  The Model 31 sampler is ideally suited for processes operating at pressures ranging from -25 inH2O to 5 psig. 

To provide the sensor with a continuous clean sample gas flow, most powder processing systems require the removal of varying amounts of particulates.  For these systems, external preconditioning components are typically included.  The blowback filter and the coalescing prefilter provide high filtration performance along with high stability, exceptional dirt holding capacity, and high flow rates with low pressure drop.

Data sheet


  • Sample Gas Pressure: -25 inH2O to 5 psig
  • Sample Gas Flow: 5 slpm (± 1 slpm) total flow
  • Drive Gas: Instrument quality compressed air or nitrogen, 35 psig (minimum) @ 2 scfm (± 0.5 scfm)
  • Sample filter: External cartridge or sintered metal filter
  • Sampling Method: 5 slpm flow via 55 inH2O vacuum draw from the aspirator
  • Vacuum Capacity: 55 inH2O (± 5 inH2O)
  • Wetted Materials: Stainless steel, glass, Teflon
  • Enclosure: 23.31”w x 14.96″ h x 8.3″ d (356 x 406 x 155 mm)
  • Weight: 35 lbs. (15.8 kg)
  • Intrinsically Safe Design — With no moving parts, the pneumatically-powered Model 31 sampler is suitable for hazardous area locations
  • Corrosion Resistant NEMA 4X Enclosure — Suitable for indoor or outdoor use with protection against ingress of dust and water
  • Integral Flow Switch — Opens contacts in alarm when sample gas flow falls below a preset level
  • Single or Dual Sensor Compatible — Option for redundant dual sensors enhances reliability
  • Low Maintenance Package — high quality components with few replacement parts minimizes maintenance costs and unplanned downtime
  • Continuous Duty — external high efficiency filter units remove particulates and contaminants from the sample gas stream