Wright Dust Feeder II

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WDF Complete with Control Module

Historical Drawing from Original Publication

WDF Showing Carbide Head

Enlarged View of WDF Gearing

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Applications

• Basic Aerosol Research
• Filtration Studies
• Inhalation Research-Lung Physiology, Toxicology Therapy
• Pharmaceutical Aerosols
• Occupational Hygiene-Atmospheric Pollution
• Nuclear Science
• Calibration of Aerosol Samplers and Instruments
• Crop Research, Deposition Studies
• Meteorology

Features

• CARBIDE CUTTER HEADS NOW STANDARD
• New smaller accessory mini chamber for lower concentrations
• Extremely Stable Output Characteristics
• Broad Range of Output from: .0026 to 60.0 Grams/Hour of Unit Density Dust
• It is Utilized by all Manufacturers of Dusty Products who are Required to Conform with the Toxic Substances Act
• All Motor Speed Selectors are Dual Voltage and select automatically

Dust is contained in the cylindrical holder (A) into which it is tightly packed. It has been found that any dust which is clean and dry with most particles below 10 micrometers diameter, can be packed in this way, and will form a stable cake; yet when the dust is scraped off the surface, it can be readily dispersed.

Dust is scraped into a groove in the surface of a scraper head (K). Along this groove a stream of air is passed so the dust is carried down the inner tube (J). At (L) it is passed through the jet which breaks up any remaining aggregates.

Scraping is carried out by rotating the dust holder (A) round the threaded spindle (F) through the intermediary of the gears (C), (E) and (D), which act as a differential gear and cause the holder to travel very slowly down the threaded spindle (F). In this way an extremely thin layer of dust is scraped off at each revolution of the holder (0.007") or 0.18mm. A variable speed motor provides adequate power for driving the mechanism over a speed range of about 1000:1.

The large dust chamber has an internal diameter of 1.5 inches (38mm). When very low concentrations are required the small chamber can be fitted which has an internal diameter of 0.530 inches. The small chamber and carbide cutter heads are supplied with the mechanism. The mini chamber has an internal diameter of 0.307 inches.

The unit is normally supplied for use with 120V, 60Hz/230V, 50Hz. Voltage is automatically selected via an internal sensor.

Capacity

With the dust packed to within 8mm (0.31 in.) of the container face, the working capacity is 40cc. With the small chamber the capacity is 5cc and for the mini chamber it is 1.3cc.

Inlet pressure and flow

With an inlet pressure of 5 PSIG or 10 PSIG the flow rate from the outlet is 12 to 15 liters per minute respectively, using a standard jet with an orifice of 0.052 inches diameter. High pressures of a least 16 PSIG are recommended for complete deaggregation. At this pressure flow, rate is approximately 25 LPM.

Speed

The differential gearing is such that the dust container will move down 0.0065 inches for each revolution that it makes (digitally displayed).

Motor for obsolete WDF-1

Many of the original English made Wright Dust feeders have been out of service for some time, due to the unavailability of original motors. This problem has now been solved and we are pleased to provide a motor and mounting plate, which are a direct replacement for these older units. 120 V, 60 Hz. Part number MO1.

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