Specification and Services.

Purpose.

To measure the concentration of a standard Na.Cl. aerosol both before and after it has passed through an air filtration device.

Sensitivity.

Better than 5 ng/m³ giving a minimum detectable penetration of less than 0.0005%. with a challenge aerosol of 13mg/m³.

Maximum Concentration.

Continuous indication of mass concentrations up to 13mg/m³, but for short periods up to 20mg/m³ if calibrated to this level.

Test Aerosol.

Produced by a single Collison atomiser as described in EN143 using a 1% Na. Cl. solution giving a range of particle sizes 0.04µm to 1.2µm with a mass mean average of 0.65µm when measuring the longest diagonal or 0.4µm if measured aerodynamically.

Gas Supply.

Hydrogen 1 l/m @ 1 bar. [ when compressed gas cylinders are used a suitable 2-stage regulator is required with the maximum out put pressure of 2 bar.]

Compressed Air

157 L/min @ 6 bar

Electrical Power.

110 to 264 Vac 40 to 400 Hz. Single Phase.

Dimensions.

1,5m long x 0,6m high x 0,55m deep.

Weight.

71 Kgs.

Finish.

Case :- Powder Coat – Mid Grey.
Front Panels :- Semi-Gloss White.

Principle of Operation.

A volume of 2 l/m of test airflow is drawn through a hydrogen flame and any Na.Cl. is burnt. When Na.Cl. is burn it generates a specific sodium yellow with a wavelength of 589 nm.

Between the flame and the PMT are neutral density filters [NDF’s], these are darken glass slides of known value, and an interference filter allowing only the sodium wavelength to pass. The NDF?s are used to prevent an overload of the PMT when higher concentrations of Na Cl are burnt and to keep the meter reading on scale.

For aerosol concentrations up to approx 0,13mg/m³ the response is linear, above this level there is some light absorption by the flame, hence the curve on the calibration graph.

The interference filter dedicates the photometer to sodium light therefore any other substances that do not burn with a sodium light are ignored in the final analysis of the penetration / efficiency of the test device.

B] The Aerosol generator consists of a 3 hole nozzle, baffle and an aerosol drying tube.

Principle of Operation.

The glass jar is charged with approx 600ml of NaCl solution at a concentration of 10g NaCl per litre. ( 1%) The atomiser nozzle is fed compressed air at 50psig; this pressure is passed through 3 holes 0,35mm dia. generating airflow of 15,5 to 13 l/m.

This high velocity air passes over 3 siphon holes which draw up solution from the jar, this impinges on a baffle, large droplets fall back into the solution, while the smaller droplets are carried to an air drying tube, in this tube the droplets remain for at least 2 secs, to allow the water to evaporate and leave crystals of NaCl to form a solid dry aerosol of a specific particle size range to challenge the device under test.

Variations of Model are available as follows.

Type No. 1100P.

Bench Rig complete with micro manometer and test fixture for media testing.

Type No. 1100C.

As Type 1100P except test fixture is for canister testing.

Type No. 1100 AL.

Bench Rig with Filter resistance, and test flow measurement connected to a PC for Aerosol loading test. Contact SFP Services for the latest revision.