DF-28B Digital Flowmeter Low Volume AS

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MODEL DF-28B LOW VOLUME AIR SAMPLER WITH DIGITAL FLOWMETER

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Notable Features
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* Display in English or metric units set at factory
* State of the Art Electronics
* Flow rate measurement and volume totalizations corrected to Standard Temperature
and Pressure
* Elapsed Time Meter
* Auto zero calibration feature of flow sensor
* Bright LED display
* Flow rate accuracy within ± 4% of full scale
* 110 - 120 VAC, 50/60 Hz; single phase
* RS-232 Communications port
* Available flow/volume units are:
SCFM - SCF
SLPM - SL
scc/min - scc
sm3/hr - sm^3

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General Description
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The Model DF-28B environmental air sampling system with digital flowmeter is a low volume
air sampler consisting of a 1/4 H.P. oil-less carbon vane vacuum pump with a constant air
flow regulator for use where a nearly constant air flow is desirable. The regulator holds a
constant pressure drop across an in-line orifice by varying the flow through a bypass valve into
the pump. This system allows the pump to work at a minimum pressure drop at all times,
permitting it to run cooler; thus extending its service life. The oil-less pump requires no
lubrication to maintain optimal efficiency during its service life. The pump is mounted on a
base plate within a weather resistant aluminum environmental enclosure having four rubber
feet. Handles are provided on the enclosure to facilitate transportation. The digital flowmeter
has a large bright LED display.

The DF-28B is designed for continuous indoor or outdoor use. This unit can be adapted for
tripod mounting if desired. Please consult the product specifications for the design
temperature range and the installation category.

The typical operating flow range is 0.5 to 4.3 CFM (14 - 122 LPM).

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Specifications
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Pump Type Oil-less, carbon vane 1/4 HP, 1725 RPM @ 60 Hz
Maximum Capacity 4.3 CFM (122 LPM) at 0" Hg Pressure drop
Ultimate Vacuum 25" Hg (635 mm Hg) at sea level
Power Requirements 110 - 120VAC; 50/60 Hz; 6 amperes; single phase
Fuse Protection 8 amperes, slow blow
Electrical Cord All temperature, 3-wire, 14 gauge
Thermal Overload Protection Furnished as an integral part of the motor.
Constant Airflow Regulator Aluminum construction with silicone diaphragm; adjustable
from 0.5 to 4.3 CFM (14-122 LPM)
Handle Steel
Dimensions 19"L × 12 ½"W × 13 ¼"H
(48.3L × 31.75W × 33.7 cm H)
Weight 59 lbs. (26.8 Kgs.)
Installation Category Pollution Degree 3
Operating Temperatures 0º to 122ºF (-18º to 50ºC)
Storage Temperature 0º to 158ºF (-18º to 70ºC)

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Electronic Specifications
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Measurement Accuracy Air flow: ± 4% of full scale
Temperature: ± 2.0ºF (1.1ºC)
Barometric Pressure 2% over measured range
Calibration Factory calibration once per
year
Communications Interface RS-232
On-Board Calculations - Flow calculation from differential pressure value using
best fit curve method
- Flow correction for standard temperature and
pressure
- Auto-zero correction utilizing Electro-pneumatic
method to compensate for offset and drift (automatic,
once every minute)
Combination Filter Holder Durable plastic combination filter holders for F&J Model
B, C or M charcoal cartridges and 47 mm, 2" or 50
mm diameter particulate filter paper are available. All
models have quick-disconnect function.

Standard Combination Filter Holders

Filter Charcoal Particulate
Holder Cartridge Paper
Model Dimensions Diameter
FJ-05P F&J Model B 2" or 50 mm
FJ-21P F&J Model C 2" or 50 mm
FJ-35P F&J Model B 47 mm
FJ-46P F&J Model C 47 mm
FJ-51P F&J Model 2" or 50 mm
FJ-53P F&J Model M 47 mm

Air Samplers

AS Digital Flowmeter Low Volume-110 V

F&J SPECIALTY PRODUCTS, INC.