NATIONAL BUREAU OF STANDARDS REPORT

7043

PERFORMANCE TEST OP A HIGH-VELOCITY

ELECTROSTATIC AIR CLEANER, MODEL HV-1

Manufactured by

Dellinger Corporation

Rochester, New York

by

C. W, Coblentz and P. R. Achenbach

Report to

General Services Administration

Public Buildings Service

Washington 25^ Do C,

<^|>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.
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; in- vention 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 Biueau’s work take the form of either actual equipment and devices or published papers. These papers appear either in the Bureau’s own series of publications or in the journals

of professional and scientific societies. The Bureau itself publishes three periodicals available from

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There are also five series of nonperiodical publications: Monographs, Applied Mathematics Series,

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National Biueau of Standards ($1.25) and its Supplement ($1.50), available from the Superintendent

of Documents, Government Printing Office, Washington 25, D.C.
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT MBS REPORT

1003-30-10630 December 19, I960 7043

PERFORMANCE TEST OP A HIGH-VELOCITY

ELECTROSTATIC AIR CLEANER, MODEL HV-1

Manufactured by

Dellinger Corporation

Rochester, New York

by

C. W, Coblentz and P, R. Achenbach

Mechanical Systems Section

Building Research Division

to

General Services Administration

Public Buildings Service

Washington 25 » D* C.

IMPORTANT, NOTICE

NATIONAL BUREAU OF STANDARDS REPORTS are usually preliminary or progress accounting documents

Intended for use within the Government. Before material In the reports Is formally published It Is subjected

to additional evaluation and review. For this reason, the publication, reprinting, reproduction,.or open-llterature

listing of this Report, either In whole or In part. Is not authorized unless permission Is obtained In writing from

the Office of the Director, National Bureau of Standards, Washington 25, D. C. Such permission Is not needed,

however, by the Government agency for which the Report has been specifically prepared If that agency wishes

to reprodiice additional copies for Its own use.

U. S. DEPARTMENT OF COMMERCE

PERFORMANCE TEST OF A HIGH-VELOCITY

ELECTROSTATIC AIR CLEANER, MODEL HV-1

Manufactured by

Dollinger Corporation

Rochester, New York

by

C. W. Coblentz and P. R. Achenbach

1 . INTRODUCTION

At the request of the Public Buildings Service, General

Services Administration, the performance characteristics of a high-velocity electrostatic precipitator. Model HV-1, manufactured by the Dollinger Corporation of Rochester, New York,

were determined. The scope of this examination inc^luded the

determination of the arrestance of the partlculate^matter in

the laboratory air and of Cottrell precipitate, the pressure

drop, and the dust-holding capacity of the specimen.

2. DESCRIPTION 0F TEST SPECIMEN

The device was manufactured and supplied for test purposes

by the Dollinger Corporation of Rochester, New York. The test

specimen was described as a "high-velocity cell."

The outside dimensions of the collector cell were 20 in.

high by 23 in. wide, and 22 3/^ in. deep; the inside air passage

measured l8 1/4 in. by 21 3/4 in. corresponding to a gross face

area of 3.20 sq ft and a net face area of 2.76 sq ft for the

cell. The collector plates were made of aluminum sheet 0.0343

in. thick and measured l8 1/2 in. by 16 in. with eleven l8 1/2

by l8 1/2 plates extended to furnish the struds between the ten

ionizer wires. The plates were spaced 5/16 in. center-to-center.

The 100-watt power pack had two high voltage terminals of

equal but opposite polarity. The positive terminal was connected to the ionizer wires and the negative terminal to the

group of collector plates which Included the struds between

the ionizer wires. The alternate collector plates were grounded.

The cell was equipped with a cleanable viscous impingement type

after-filter, Air-Maze Corporation Type P~3>, measuring 23 in.

by 19 3/4 in. by 1 7/8 in. outside and having a net face area

of 21 3/4 in. by l8 1/8 in., or 2.69 sq ft.
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3. TEST METHOD AND PROCEDURE

The arrestance measurements were made in accordance with

the ”NBS Dust Spot Method” described In a paper by R. S. Dill

and entitled ”A Test Method for Air Filters" (ASHVE Transactions, Vol. 44, p. 379. 1938 ).

For test purposes, the collector cell was Installed In

the test apparatus and carefully sealed to prevent Inward

leakage of air 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 two feet upstream and eight feet downstream of the test

specimen at equal rates and passed through known areas of

Whatman No. 4l filter paper. The change of the opacity of

these areas was determined with a sensitive photometer which

measured the light transmission of the same spot on each sampling paper before and after the test. The two sampling papers

used for each test were selected to have the same light transmission readings when clean.

For determining the arrestance of the filter with Cottrell

precipitate as the test dust, different size areas of sampling

papers were used upstream and downstream of the filter In order

to obtain a similar Increase of opacity on both sampling papers.

For each arrestance determination with Cottrell precipitate,

the upstream sample of the aerosol was collected on one filter

paper for half of the test period and on a second filter paper

during the remainder of the test period. The downstream sampling paper collected the dust for the entire test. This method

was UB'^d to avoid excessive differences In the dust spots when

deterfftihlng Cottrell precipitate arrestance values above 95

percent. The arrestance, A (in percent), was then calculated

by the formula:

where Su and Sp are the upstream and downstream sampling areas

and AUi, AU2 . and AD the observed changes In the opacity of

the two upstream and , one downstream sampling papers, respectively.

For determining the arrestance of the particulate matter

In the laboratory air, equal sampling areas were used for the

upstream and downstream samplers. A similar Increase of the

opacity of the upstream and downstream filter papers was obtained
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by passing the sampling air through the upstream paper only part

of the time while operating the downstream sampler continuously.

This was accomplished by Installing a solenoid valve In the upstream sampling line and using another one to by-pass the upstream sampler and first solenoid valve. The valves were operated by an electric timer and a relay so that one was open while

the other one was closed during any desired percentage of the

5-mlnute timer cycle, reversing the position of the two valves

during the remainder of the cycle. The arrestance, A (in percent), was then determined with the following formula:

A = 100 - T X _AU

where T Is the percentage of time during which air was drawn

through the upstream sampler, AU and AU being the changes of

opacity of the sampling papers, as previously Indicated,

After Installing the device, the power pack was connected

to the laboratory electric supply line and the static potentials at 115 volts Input measured with an electrostatic kilovoltmeter were then 6,500 volts. By means of a variable voltage transformer, the line voltage was adjusted during subsequent readings of the static voltage to II5 volts ± 1/4 volt

but was allowed to drift between readings.

Several arrestance determinations, made under this condition,

using the particulate matter In the laboratory air as the aerosol, Indicated that the air flow rate at which 90^ arrestance

was obtained had to be reduced below the design air flow rate

of 1800 cfm. After consulting with the manufacturer, the static potential was raised to ± 6,850 volts, and the arrestance

with atmospheric air was again determined.

Following the Initial arrestance determinations with the

particulate matter In the laboratory air as the aerosol, the

arrestance of the device was determined with laboratory air

Into which Cottrell precipitate was dispersed at a rate of one

gram per thousand cubic feet of air. The loading of the filter

was then commenced with 4 parts lint by weight added to every

96 parts of Cottrell precipitate. The Cottrell precipitate had

been previously sifted through a 100-mesh screen and the lint

was prepared from No. 7 cotton llnters which were ground In a Wiley mill with a 4 mm screen. Each aerosol was dispersed

separately Into the air stream. As the loading progressed,

arrestance determinations were made at selected Intervals using

either the laboratory air alone or laboratory air with Cottrell

-4-

preclpltate. No lint was introduced into the test apparatus

during the arrestance determinations with Cottrell precipitate,

but an appropriate amount of lint was added to maintain the

overall ratio of 4 to 96. The pressure drop across the test

specimen, the ionizer and plate voltages, and the frequency of

noticeable electrostatic discharges were recorded at each arrestance determination and also after each Increment of 20 grams

of Cottrell precipitate had been Introduced into the test

apparatus

.

Thirteen arrestance determinations were made during the

loading period with air flow rates ranging from 1,400 to 2,200

cfm using either Cottrell precipitate or the particulate matter

of the laboratory air as the aerosol. A total of 1,214 grams

of Cottrell precipitate and lint were Introduced into the test

apparatus during the loading in conformance with the regular

practice of terminating the test of such filters with a dust

load of 2/3 grams for each cfm rated air flow.

4. TEST RESULTS

The test specimen had a rated air flow rate of 1,800 cfm

with a gross face area of 3.20 sq ft. This corresponded to a face velocity of 563 ft/mln.

A summary of the test results is presented in Table 1 and

shows the air flow rates, dust load, pressure drop, and arrestance values observed with the particulate matter in the laboratory air as well as with Cottrell precipitate as the aerosol.

The effect of the dust load on the pressure drop and on the arrestance of the particulate matter in the laboratory air is

plotted in Figure 1 and smooth curves were fitted to the plotted

points.

- 5

-

Table 1

Performance of the

Bollinger Corporation Electrostatic Precipitator

(at ± 6850 volts potential)

Air Flow Rate Dust Load Pressure Drop Arrestance Aerosol

cfm grams in. W. G. %

**

1400 0 0.116 95.1* A

1800 0 0.183 91.1* A

2200 0 0.257 87.8* A

1800 12 0.183 97.8 C

1800 323 0.229 97.9 C

1800 323 0.229 90.9 A

1800 601 0.296 90.9 A

1800 974 0.399 90.5 A

1800 1202 0.508 89.0 A

1800 1214 0.513 95.4 C

* Average of two tests.

** A = Particulate matter in laboratory air.

C = Cottrell precipitate in laboratory air.

It will be noted that the arrestance of atmospheric dust

at the rated air flow rate was 91.1 percent with a clean filter

and 89.0 percent with a dust load of 1^202 grams. The pressure

drop increased during loading from an initial value of O.II6 in.

W.G. to 0.508 in. W.G. Reducing the air flow rate to 1_,400 cfm

Increased the initial arrestance to 95.1 percent while an increase

to 2^200 cfm reduced it to 87.8 percent. The average arrestance

of Cottrell precipitate was 97 percent.

Table 2 shows the arrestance of the test specimen at two

different static potentials giving a comparison between the initial tests at 6^500 volts and the later tests at 6,850 volts.

The values are plotted in Figure 2 . The arrestance at 6,500

volts was extrapolated above 1,800 cfm as a dashed line. The

difference in the arrestance at the two static potentials was

1.9 percent at 1,400 cfm air flow rate; it increased to 2.2 percent at 1,800 cfm, and to approximately 2.5 percent at 2,200 cfm.

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Table 2

Arrestance at Reduced Static Potential

Air Plow Rate, cfm l400 1800 2200

6,500 volts

6,850 volts

93.2 88„9 85 o 2*

95.1 91.1 87.8

* extrapolated from Figure 2.

An examination of the collector cell at the conclusion of

the test showed that all plates were about evenly covered with

a light layer of dust. The after-filter and the collector cell

were washed with water and no difficulty was encountered in

cleaning out the dust that had accumulated during the test.

The number of electrical discharges between plates observed

during the tests reached, at one time, 19 per minute but it was

considerably less during most of the test and no discharges at

all were noticed during about half of the operating time.

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U.S. DEPARTMENT OF COMMERCE

Fx-eclei'iclc H. Mueller, 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

Bouldei;, Colo., 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. METROLOGY. Photometry and Coloiimetry. Refractometry. Photographic Research. Length. Engineering

Metrology. Mass and Scale. Volumetry and Densimetry.

HEAT. Temperature Physics. Heat Measurements, Cryogenic Physics. Rheology. Molecular Kinetics. Free

Radicals Research. Equation of State. Statistical Physics. Molecular Spectroscopy.

RADIATION PHYSICS. X-Ray. Radioactivity, Radiation Theory. High Energy Radiation. Radiological

Equipment. Nucleonic Instrumentation. Neutron Physics.

CHEMISTRY. Surface Chemistry. Organic Chemistry. Analytical Chemistry. Inorganic Chemistry. Electrodeposition. Molecular Structure and Properties of Gases. Physical Chemistry. Thermochemistry. Spectrochemistry. Pure Substances. MECHANICS. Sound. Pressure and Vacuum. Fluid Mechanics. Engineering Mechanics. Combustion Controls. ORGANIC AND FIBROUS MATERIALS. Rubber. Textiles. Paper. Leather. Testing and Specifications.

Polymer Structure. Plastics. Dental Research. METALLURGY. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion. Metal Physics.

MINERAL PRODUCTS. Engineering Ceramics. Glass. Refractories. Enameled Metals. Constitution and

Microstructure.

BUILDING RESEARCH. Structural Engineering. Fire Research. Mechanical Systems. Orgjanic Building Materials. Codes and Safety Standards. Heat Transfer. Inorganic Building Materials. APPLIED MATHEMATICS. Numerical Analysis. Computation. Statistical Engineering. Mathematical

Physics.

DATA PROCESSING SYSTEMS. Components and Techniques. Digital Circuitry. Digital Systems. Analog

Systems. Applications Engineering.

ATOMIC PHYSICS. Spectroscopy. Radiometry. Mass Spectrometry. Solid State Physics. Election Physics.

Atomic Physics.

INSTRUMENTATION. Engineering Electronics. Electron Devices. Electronic Instrumentation. Mechanical

Instruments. Basic Instrumentation.

Office of Weights and Measures. BOULDER, COLO.

CRYOGENIC ENGINEERING. Cryogenic Equipment. Cryogenic Processes. Properties of Materials. Gas

Liquefaction.

IONOSPHERE RESEARCH AND PROPAGATION. Low Frequency and Very Low Frequency Research. Ion- osphere Research. Prediction Services. Sun-Earth Relationships. Field Engineering. Radio Warning Services. RADIO PROPAGATION ENGINEERING. Data Reduction Instrumentation. Radio Noise. Tropospheric Measurements. Tropospheric Analysis. Propagation-Terrain Effects. Radio-Meteorology. Lower Atmosphere Physics.

RADIO STANDARDS. High frequency Electrical Standards. Radio Broadcast Service. Radio and Microwave

Materials. Atomic Frequency and Time Standards. Electronic Calibration Center. Millimeter-Wave Research. Microwave Circuit Standards.

RADIO SYSTEMS. High Frequency and Very High Frequency Research. Modulation Research. Antenna Research. Navigation Systems. Space Telecommunications.

UPPER ATMOSPHERE AND SPACE PHYSICS. Upper Atmosphere and Plasma Physics. Ionosphere and

Exosphere Scatter. Airglow and Aurora. Ionospheric Radio Astronomy.