NATIONAL BUREAU OF STANDARDS REPORT

7515

PERFORMANCE TESTS OF A CLEANABLE VISCOUS- IMPINGEMENT AIR FILTER,

MODEL NO. 914 M-V TYPE EZKLEEN

Manufactured by

Research Products Corporation

Madison, Wisconsin

by

C. W. Coblentz and P. R, Achenbach

Report to

U.S. Army Chemical Procurement District

New York 7, N.Y.

<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March 3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and maintenance of the national standards of measurement and the provision of means and methods for making measurements consistent

with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials, devices, and structures; advisory services to government agencies on scientific and technical problems; invention and development of devices to serve special needs of the Government; and the development of standard practices, codes, and specifications. The work includes basic

and applied research, development, engineering, instrumentation, testing, evaluation, calibration services,

and various consultation and information services. Research projects are also performed for other government

Agencies when the work relates to and supplements the basic program of the Bureau or when the Bureau’s

unique competence is required. The scope of activities is suggested by the listing of divisions and sections on the inside of the back cover.

Publications

The results of the Bureau’s research are published either in the Bureau’s own series of publications or

in the journals of professional and scientific societies. The Bureau itself publishes three periodicals avail- able from the Government Printing Office: The Journal of Research, published in four separate sections,

presents complete scientific and technical papers; the Technical News Bulletin presents summary and pre- liminary reports on work in progress; and Basic Radio Propagation Predictions provides data for determining

the best frequencies to use for radio communications throughout the world. There are also five series of nonperiodical publications: Monographs, Applied Mathematics Series, Handbooks, Miscellaneous Publications,

and Technical Notes. A complete listing of the Bureau’s publications can be found in National Bureau of Standards Circular

460, Publications of the National Bureau of Standards, 1901 to June 1947 (SI. 25), and the Supplement to National Bureau of Standards Circular 460, July 1947 to June 1957 ($1.50), and Miscellaneous Publication 240,

July 1957 to June 1960 (Includes Titles of Papers Published in Outside Journals 1950 to 1959) ($2.25); avail- able from the Superintendent of Documents, Government Printing Office, Washington 25, D. C.
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

1003-30-10630 May 23i 1962 7515

PERFORMANCE TESTS OF A CLEANABLE VISCOUS-IMPINGEMENT AIR FILTER,

MODEL NO. 914 M-V TYPE EZKLEEN

Manufactured by

Research Products Corporation

Madison, Wisconsin

by

C. W. Coblentz and P, R. Achenbach

Mechanical Systems Section

Building Research Division

to

U.S. Army Chemical Procurement District

New York "J 3 N.Y.

IMPORTANT NOTICE

NATIONAL BUREAU OF STA

intended for use within the C to additional evaluation and re listing of this Report, either ir the Office of the Director, Nat however, by the Government s to reproduce additional copies

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST) on October 9, 2015.

ogress accounting documents

Tally published it is subjected

sproduction, or open-literature on is obtained in writing from

luch permission is not needed,

repared if that agency wishes

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

PERFORMANCE TESTS OF A CLEANABLE VISCOUS- IMPINGEMENT AIR FILTER

MODEL NO* 914 M-V TYPE EZKLEEN

Manufactured by

Research Products Corporation

Madison., Wisconsin

by

C. W. Coblentz and P. R. Achenbach

1 . Introduction

At the request of the U.S. Army, Chemical Procurement

District, New York the performance characteristics of a preproduction sample of a cleanable viscous-impingement type air filter were determined for compliance with the requirements in

Table 1, paragraph 4.2.2 of Federal Specification F-F-300 dated

October 29^ 1957.* and entitled Cleanable Viscous-Impingement

type Air-Conditioning Filters using the applicable procedures

listed in the table. The scope of this examination included the

determination of the arrestance of Cottrell precipitate In laboratory air, the pressure drop, and the dust-holding capacity at

a face velocity of 350 ft/min, and the cleanability of the test

specimen.

2 . Description of Test Specimen

The test specimen was manufactured by the Research Products

Corporation of Madison, Wisconsin. It was identified as Model

No. 914 M-V Type E Z Kleen and was supplied for test purposes by

the U.S. Army, Chemical Procurement District, New York.

The nominal size of the filter was 20 x 16 x 1 inches, the

actual dimensions were 19 9/16 x 15 5/6 x J/3 inches. The filter

media was held by a frame made of aluminum sheet formed into a Ushaped channel with a free opening of 17 3/4 x 13 7/6 inches,

corresponding to a net face area of 1.71 sq ft. The weight of the

clean filter oiled and drained was 4/2 g (approximately 1 lb.).

The filter medium consisted of a stack of aluminum sheets,

each of which had been slit and expanded to resemble a screen.

The perforations of the screens on the upstream side of the filter were larger than those on the downstream side. The filter

media was supported within the frame by an aluminum wire grid of

4 1/2 In. squares on the downstream side of the filer and by a diagonal cross of wire on the face side.
- 2 -

The adhesive supplied by the manufacturer was identified

as ’’Super Filter Coat” and was said to have odor-absorbing properties. This characteristic was not investigated in this test.

3 . Test Method and Procedure

The filter was tested at a face velocity of 350 ft/min. corres- ponding to an air flow rate of 600 cfm. The arrestance determinations were made with the NBS "Dust Spot Method" described in a paper by R. S. Dill entitled,, "A Test Method for Air Filters/’

(ASHVE Transactions , Vol. 44, p. 379, 1935). The filter under

test was supported in a frame which fitted the test apparatus and

was carefully sealed to prevent any by-pass of air or inward leakage into the test apparatus, except through the measuring orifice.

The desired rate of air flow through the filter was established,

and samples of air were drawn from the center points of the test

duct 2 feet upstream and 8 feet downstream of the test specimen

at equal rates, and passed through known areas of Whatman No. 4l

filter paper. The arrestance determinations were made with laboratory air into which Cottrell precipitate was injected and

diffused at a ratio of 1 gram per 1,000 cu ft of air.'

The two sampling papers used for each arrestance determination

were selected to have the same light transmission when clean.- The

light transmission was measured with a sensitive photometer on the

same portion of each paper before and after the test. In order to

obtain similar increases of opacity with both samplers, different

size areas were used upstream and downstream of the filter. The

arrestance, A (in percent), was calculated by the following formulae

A x

AD

AU x 100

where and Sp are the downstream and upstream areas and AD and

AU the observed changes in the opacity of the downstream and

upstream sampling areas, respectively.

Whereas the arrestance determinations were made with Cottrell

precipitate only, cotton lint was added during the loading process

in a ratio of 4 parts to every 96 parts by weight of Cottrell precipitate, including that amount used for arrestance measurements.

The Cottrell precipitate had been previously sifted through a 100

mesh screen and the cotton lint was prepared by grinding No. 7

cotton linters in a Wiley mill with a 4 millimeter screen.

Arrestance determinations were made at the beginning and at

the end of the loading period of each test specimen and at several

Intermediate load conditions. The pressure drop across the filter
-3-

under test was recorded after each increment of 20 grams of dust

had been introduced into the test duct. . The test was terminated

when the pressure drop reached 0.5 in. W.G.

4 . Test Results

The results of the test are presented in Table 1 which shows

the values determined for the pressure drop and the arrestance at

different dust load conditions.

Table 1

PERFORMANCE OF RESEARCH PRODUCTS CORPORATION

AIR FILTER MODEL NO. 914 M-V TYPE EZKLEEN

(Face Velocity, 350 ft/min)

Dust Load

~~g/sq ft

0

55

106

162

214

234

268

286

Pressure Drop

in. W.G.

0.050

0.075

0.117

0.176

0.285

0.339

0.458

0.510

Arrestance

%

45

45

48

46

53

51

The "Dust Load'* shown in this table is the average dust

received by each square foot of net filter area. It Is the

weight of the Cottrell precipitate and lint introduced Into the

test apparatus, divided by the net face area of the filter and

diminished by the percentage of dust fallout upstream of the

filter. This dust fallout was determined at the conclusion of

the test by sweeping out the test duct upstream of the test

specimen and calculating the percentage of fallout in relation

to the total dust introduced. Figure 1 is a graph of the values

shown In Table 1.

It will be noted that the arrestance of the clean filter was

45 percent with a pressure drop of 0.050 in. W.G, The arrestance

Increased to 53 percent with a dust load of 214 g/sq ft and a pressure drop of 0,285 in. W.G, The final dust load at 0.510

In. W.G. was 286 g/sq ft.
-4-

The test specimen was loaded twice and cleaned and freshly

oiled after each test. Although the pressure drop across the

filter was observed to the nearest 0.001 in. W.G., no change

of the pressure drop could be determined after two loading and

cleaning cycles. Figure 1 indicates that the dust load at

0.400 in. W.G. was 255 g/sq ft and that the average arrestance

was approximately 48 percent. A comparison of the observed

results and the requirements of Federal Specification F-F-300

is made in Table 2, showing compliance with respect to initial

arrestance, dust-holding capacity, and cleanability.

Table 2

COMPARISON OF TEST RESULTS WITH REQUIREMENT

OF FEDERAL SPECIFICATION F-F-300

Required Observed

Initial Arrestance, % ”45“ “45

Dust Holding Capacity

at 0.4 in. W.G., g/sq ft. 250 255

Increase of Pressure Drop ' After Loading and Cleaning, In. W.G. 0. Olmax. <.001

USCOMM-NBS-DC
RQDUCT8

.ILBANAH IIMEIHGEMEHI

v ty: 3e ezkleen

.EDICEFY

U. S. DEPARTMENT OF COMMERCE

Luther H. Hodges, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards at its major laboratories in Washington, D.C., and

Boulder, Colorado, is suggested in the following listing of the divisions and sections engaged in technical work.

In general, each section carries out specialized research, development, and engineering in the field indicated by

its title. A brief description of the activities, and of the resultant publications, appears on the inside of the

front cover, WASHINGTON, D. C.

Electricity. Resistance and Reactance. Electrochemistry. Electrical Instruments. Magnetic Measurements

Dielectrics, High Voltage.

Metrology. Photometry and Colorimetry. Refractometry. Photographic Research. Length. Engineering Metrology.

Mass and Scale. Volumetry and Densimetry.

Heat. Temperature Physics. Heat Measurements. Cryogenic Physics. Equation of State. Statistical Physics.

Radiation Physics. X-ray. Radioactivity. Radiation Theory. High Energy Radiation. Radiological Equipment.

Nucleonic Instrumentation. Neutron Physics.

Analytical and Inorganic Chemistry. Pure Substances. Spectrochemistry. Solution Chemistry. Standard Refer- ence Materials. Applied Analytical Research. Crystal Chemistry.

Mechanics. Sound. Pressure and Vacuum. Fluid Mechanics. Engineering Mechanics. Rheology. Combustion

Controls. Polymers. Macromolecules: Synthesis and Structure. Polymer Chemistry. Polymer Physics. Polymer Characterization. Polymer Evaluation and Testing. Applied Polymer Standards and Research- Dental Research.

Metallurgy. Engineering Metallurgy. Microscopy and Diffraction. Metal Reactions. Metal Physics. Electrolysis

and Metal Deposition.

Inorganic Solids. Engineering Ceramics. Glass. Solid State Chemistry. Crystal Growth. Physical Properties.

Crystallography.

Building Research. Structural Engineering. Fire Research. Mechanical Systems. Organic Building Materials. Codes and Safety Standards. Heat Transfer. Inorganic Building Materials. Metallic Building Materials. Applied Mathematics. Numerical Analysis. Computation. Statistical Engineering. Mathematical Physics. Operations Research. Data IVocessissg Systems. Components and Techniques. Computer Technology. Measurements Automation.

Engineering Applications. Systems Analysis.

Atomic Physics, Spectroscopy. Infrared Spectroscopy. Solid State Physics. Electron Physics. Atomic Physics.

Instrumentation. Engineering Electronics. Electron Devices. Electronic Instrumentation. Mechanical Instru- ments. Basic Instrumentation. Physical Chemistry. Thermochemistry. Surface Chemistry. Organic Chemistry. Molecular Spectroscopy. Molecular Kinetics. Mass Spectrometry.

Office of Weights and Measures. BOULDER, COLO.

Cryogenic Engineering Laboratory. Cryogenic Equipment. Cryogenic Processes. Properties of Materials. Cryogenic Technical Services. CENTRAL RADIO PROPAGATION LABORATORY

Ionosphere Research and Propagation. Low Frequency and Very Low Frequency Research. Ionosphere Research. Prediction Services. Sun-Earth Relationships. Field Engineering. Radio Warning Services. Vertical Soundings Research.

Radio Propagation Engineering. Data Reduction Instrumentation. Radio Noise. Tropospheric Measurements.

Tropospheric Analysis. Propagation-Terrain Effects. Radio-Meteorology. Lower Atmosphere Physics.

Radio Systems. Applied Electromagnetic Theory. High Frequency and Very High Frequency Research. Modulation Research. Antenna Research. Navigation Systems.

Upper Atmosphere and Space Physics. Upper Atmosphere and Plasma Physics. Ionosphere and Exosphere Scatter, Airglow and Aurora. Ionospheric Radio Astronomy.

RADIO STANDARDS LABORATORY

Radio Physics. Radio Broadcast Service. Radio and Microwave Materials. Atomic Frequency and Time-Interval

Standards. Millimeter-Wave Research.

Circuit Standards. High Frequency Electrical Standards. Microwave Circuit Standards. Electronic Calibration Center.