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Program for ... annual Citrus Processor's Meeting.
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Table of Contents
    Cover
        Cover
    Foreword
        Foreword
    Main
        Page 1
        Page 2
        Page 3
        Page 4
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        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
    A peristaltic pump for liquid chlorine injections in low pressure irrigation systems
        Page A-1
        Page A-1a
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        Page A-3
        Page A-3a
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Full Text














PROGRAM


University of Florida
Agricultural Research & Education Center
Post Office Box 1088
Lake Alfred, Florida 33850

Thursday, September 30, 1976

Registration--9:00 A.M.

Welcome and Introductory Remarks--9:35 A.M.

Dr. H. J. Reitz, Director
Agricultural Research and Education Center
University of Florida, IFAS
Lake Alfred, Florida

Morning Program--9:35-12:00

Chairman: Mr. Charles Hendrix
Citrus Central, Inc.
Orlando, Florida

Energy utilization and material balance during manufacture of dried
citrus pulp.
James W. Kesterson and R. J. Braddock, University of Florida.

Energy conservation and quality improvement in citrus concentrate
by computer controlled evaporation in citrus processing--a project
outline.
R. D. Carter, Florida Department of Citrus.

Mechanical harvesting and the citrus processing industry:

A. Current status of mechanical harvesting practices.
James G. Blair, Florida Department of Citrus.

B. The present outlook of abscission chemicals.
W. C. Wilson, Florida Department of Citrus

C. Harvesting systems for cannery fruit.
Scott Hedden, U. S. Department of Agriculture.

Some characteristics of commercial orange juice packed during 1975-
1976 season.
Rodger Barron, Florida Department of Citrus.















OJ BREAK


Analysis of hesperidin and neohesperidin dihydrochalcone by HPLC and
simplification of limonin HPLC procedure.
J. F. Fisher, Florida Department of Citrus.

Trace metal analysis by plasma source emission spectroscopy.
J. A. McHard, Florida Department of Citrus.

A survey of trace amounts of lead and tin in canned citrus juices
using the flame and flameless atomic absorption spectroscopy.
R. L. Rouseff, Florida Department of Citrus.



12:00 N 00 N LUNCH


Afternoon Program--1:30-3:30

Chairman: Mr. Kenneth W. Hastings
Orange-Co. Inc.
Bartow, Florida

An overview of Young Tree Decline (YTD) research at the Agricultural
Research and Education Center.
E. P. DuCharme, University of Florida.

The possible use of neohesperidin-dihydrochalcone as a sweetener in
grapefruit juice.
P. J. Fellers, Florida Department of Citrus.

Quantitative determination of sorbic acid and sodium benzoate in
citrus juice.
Margaret Bennett and D. R. Petrus, Florida Department of Citrus.

Yield and quality of by-products made from cull, split, and dropped
fruit.
R. J. Braddock and J. W. Kesterson, University of Florida.

Recovery of naringin from pectin leach water from grapefruit albedo.
P. G. Crandall and J. W. Kesterson, University of Florida.












-3-


Color of high density concentrate as affected by time and temperature
of storage and by variety of fruit.
R. L. Huggart and D. R. Petrus, Florida Department of Citrus.

Orange juice color measurement by conventional tristimulus color-
imeter.
Bradley Eagerman, University of Florida.















ENERGY UTILIZATION AND MATERIAL BALANCE FOR THE VINCENT/LUND
EXPERIMENTAL CITRUS PROCESSING SYSTEM--J. W. Kesterson, and
R. J. Braddock, University of Florida, Lake Alfred.

Work supported by the Center for Environmental Programs of the
Institute of Food and Agricultural Sciences has been in progress
since July 1973 to study energy consumption as related to citrus
processing. The Vincent/Lund system was selected because it was the
only equipment available at the time and seemed to be a good starting
point. To date, our work has sought to accomplish the following:

1. Minimize fuel costs by utilizing waste heat from our pilot
plant feed mill to produce 60Brix juice concentrate and a
35-40Brix molasses for add back to peel prior to drying.

2. Eliminate air pollution problems associated with feed mills.

Once the equipment was made operational, tests were made and
results to date indicate that:

1. A satisfactory 60-650Brix concentrate of low viscosity can
be produced in the MED-TEMP evaporator. The juice evaporator
was operated off vapors obtained from the flash evaporator
(for manufacture of 35-40Brix molasses) and required no
boiler steam.

2. A satisfactory 35-40Brix molasses can be produced in the
flash evaporator for add back to the peel before drying.
In addition to producing molasses, the flash evaporator serves
as a scrubber to remove particulate emissions from feed mill
stack gases.

3. From an overall energy standpoint, the following data have
been collected:

a. Feed mill dryer 1569 BTU/lb H 0 Evap.
b. Flash evaporator 1299 "
c. Flash evaporator+feed mill 1466 "
d. Double effect evaporator 711 " "
e. Overall heat balance (a+b+d) 685 "














-5-


Heat balance data for the flash evaporator-double effect
evaporator combination are considered to be high, since the water
supply at the AREC-LA has been insufficient to supply the barometric
leg. This has necessitated operation of the flash evaporator at
53% of rated capacity which has prevented the operation of this
equipment at maximum efficiency.















ENERGY CONSERVATION AND QUALITY IMPROVEMENT OF CITRUS CONCENTRATES
BY COMPUTER CONTROLLED EVAPORATION--Robert D. Carter*, Florida
Department of Citrus, Lake Alfred.

Purpose:

To investigate computer control as a means of reducing energy
used in commercial citrus juice evaporation and consequently improve
concentrate quality.

Methods:

1. Use team approach utilizing special abilities of FDOC and
AREC-LA staff and the pilot plant TASTE evaporator.

2. Determine factors which influence or control juice
evaporation in the TASTE evaporator.

3. Develop adequate methods of monitoring energy use and
system changes within the pilot plant TASTE evaporator
during operations.

4. Explore methods of instrument-computer interface to
facilitate evaporation control.

5. Minimize energy used in juice evaporation.

6. Monitor quality during tests so that as energy is minimized,
quality can be maximized.

7. Maintain liason with key industry representatives for
interpreting results and eventually applying them to
commercial equipment.

*This project is undertaken with the cooperation of the following
AREC and DOC staff members: Dr. B. S. Buslig, Dr. P. C. Crandall,
Dr. Bradley Eagerman, G. J. Edwards, Dr. W. M. Miller, and
Dr. T. A. Wheaton.
















MECHANICAL HARVESTING AND THE CITRUS PROCESSING INDUSTRY

A. CURRENT STATUS OF MECHANICAL HARVESTING PRACTICES--
James G. Blair, Florida Department of Citrus.

A report on the general status of the Mechanical Harvesting
Program is given and the effect of the recent economic recession on
the development of viable harvesting systems is discussed.

B. CURRENT STATUS OF ABSCISSION CHEMICALS--W. C. Wilson,
Florida Department of Citrus.

Abscission chemical research with regard to fruit for
processing has continued with the most significant advances being
in the use of chemical combinations. We have found that
combinations of RELEASE, ACTI-AID, and chlorothalonil give
superior loosening, less fruit damage and phytotoxicity than the
chemicals used individually, and reduce overall the total amounts
of chemicals required by 25-50%. The FDOC is working cooperatively
with the three commercial companies involved to obtain experimental
clearance for the combinations and expects to continue expanded tests
with them this season.

C. HARVEST SYSTEMS FOR CANNERY FRUIT--Scott L. Hedden, U. S.
Department of Agriculture, Agricultural Research Service

The harvest mechanization research program at Lake Alfred has
developed and/or evaluated a wide variety of picking aids, man-
positioners, fruit locating devices, and mechanisms to twist, flail,
strip, or shake the fruit from the tree. A few of the mass removal
concepts continue to show promise in a systems approach to
harvesting cannery fruit. Adaptation of existing harvesting
machinery has been slow for several reasons, one of which is the
two-crop 'Valencia' orange. However, new abscission chemicals,
now available, can selectively loosen 'Valencia' oranges so that
harvest systems can function throughout the harvest season.

A slide presentation will show harvest systems in use or
under development by the Lake Alfred Research group.












-8-


SOME CHARACTERISTICS OF COMMERCIAL ORANGE JUICE PACKED DURING 1975-
1976 SEASON--R. W. Barron, Florida Department of Citrus.

During the 1975-76 citrus season, 95 samples of commercial FCOJ
from Florida plants were examined for flavor and color. In addition,
physical and chemical analyses relating to juice quality were
conducted. Samples were collected on approximately the first of each
month from 12 to 19 plants represented at any one collection period.

Flavor evaluations of reconstituted FCOJ were compiled from the
opinions of Agricultural Research and Education Center taste panel
members. Samples were graded on a 9 category hedonic scale ranging
from like extremely to dislike extremely. The percentage of FCOJ
samples for the 1975-76 and 1974-75 citrus seasons respectively that
fell in the following flavor categories were: like very much 3, 2;
like moderately 63, 59; like slightly 30, 35; neither like nor
dislike 3, 4; and dislike slightly 1, 0.

Average Hunterlab Citrus Colorimeter Citrus Red and Citrus
Yellow values indicate that the color of FCOJ this season was about
the same as the previous season.



Twenty-five pasteurized orange juice (POJ) samples were examined
for flavor and color during the 1975-76 citrus season. Samples were
collected on approximately the first of each month from 4 to 5 plants
represented at any one collection period. Flavor evaluations of POJ
were made by an Agricultural Research and Education Center taste
panel. Scores for flavor were based on a 9 category hedonic scale
going from like extremely to dislike extremely. The flavor scores
with percentages for 1975-76 and 1974-75 respectively were as follows:
like very much 0, 8; like moderately,- 8, 38; like slightly 52,
46; neither like nor dislike 28, 8; dislike slightly 8, 0; and
dislike moderately 4, 0.

Average Hunterlab Citrus Colorimeter Citrus Red and Citrus
Yellow values indicate that the color of POJ this season was about
the same as last season.
















ANALYSIS OF HESPERIDIN AND NEOHESPERIDIN DIHYDROCHALCONE BY HPLC AND
SIMPLIFICATION OF THE LIMONIN HPLC PROCEDURE--James F. Fisher, Florida
Department of Citrus.

High pressure liquid chromatographic (HPLC) procedures have been
developed for the determination of neohesperidin dihydrochalcone
(NHDHC) and hesperidin. The NHDHC is a non-nutritive sweetening
agent which may have the potential as an artificial sweetener of
citrus. Hesperidin does not contribute to juice quality, but its
concentration in orange juice may be used as an indicator of extrac-
tion pressure.

Grapefruit juice containing NHDHC was injected onto a C-18 column
and eluted isocratically with a 75/25 water acetonitrile system.
Detection was accomplished at 280 nm. The NHDHC was eluted in about
10 minutes.

Filtered orange juice was injected onto a C-18 column. The
hesperidin was eluted isocratically in 11.7 minutes with an 80/20
water acetonitrile system. Detection was accomplished at 285 nm.

The preparation of the sample used in the HPLC determination of
limonin has been simplified. Both the centrifugation and clarifica-
tion filtration steps have been eliminated. The extraction step has
been shortened. This has reduced the sample preparation time to about
30 minutes.












-10-


TRACE METAL ANALYSIS BY PLASMA SOURCE ATOMIC SPECTROSCOPY--J. A.
McHard, Florida Department of Citrus.

Atomic spectroscopy can be classified into three general
categories: 1. atomic emission, 2. atomic absorption, and
3. atomic fluorescence. This presentation will deal with relatively
recent developments in atomic emission spectroscopy.

Atomic emission spectroscopy was early recognized as a useful and
sensitive analytical tool for the measurement of elements in a variety
of sample types. As early as the 1930's commercial models had reached
design stages that have undergone few improvements even to this day.
One recent significant step forward in design has been the introduction
of the plasma jet as a source in place of the arc, spark, or flame.
This new source has allowed the achievement of better detection limits
and allows more ease in the introduction of liquid samples.

A commercial plasma source atomic emission spectrometer, which
has been employed to detect elements in orange juice at levels never
before measured, is described. Besides providing good detection
limits for metal elements, it permits the measurement of certain
non metals like boron and phosphorus. Plasma source atomic emission
spectroscopy combines the ease of sample handling of flame emission
spectroscopy and the range of elements which can be determined by
arc emission spectroscopy.












-11-


A SURVEY OF TRACE AMOUNTS OF LEAD AND TIN IN CANNED CITRUS JUICES
USING FLAME AND FLAMELESS ATOMIC ABSORPTION SPECTROSCOPY--Russell
Rouseff, Florida Department of Citrus.

Results of a market survey of canned citrus juices for lead and
tin are presented. Samples were collected from store shelves from
several areas across the United States beginning in November 1975
and continuing into 1976. Results of a controlled storage experiment
with grapefruit juice are also presented. The pH of freshly extracted
grapefruit juice was adjusted to represent the extremes likely to be
found with this juice, which was then canned and stored at different
temperatures for different periods of time before being analyzed.

The importance of the type of sample preparation on the
analytical results as well as the possible sources of error is
discussed. A brief presentation on the methods of analysis is
given.













-12-


YOUNG TREE DECLINE--E. P. Ducharme, University of Florida, IFAS.

Young tree decline (YTD) was recognized in 1965 as a new and
potential production problem of citrus trees in Florida groves.
At that time, less than 500 acres were involved. Within 5 years,
1970, YTD was considered to be a major problem and there were up to
25,000 acres affected. In 1975, at least 75,000 acres of citrus
have been estimated to be affected and production of fruit seriously
limited or nonexistent in these groves. Individually affected
groves and blocks of trees have suffered 100% loss of trees within
10 years from the time that the problem first appeared.

Research by IFAS scientists at research centers of Lake Alfred,
Fort Pierce, and departments at the Main Station, Gainesville, has
been pursued with increasing vigor since YTD was recognized as a
serious problem. Currently more than $300,000 of the resources at
the Lake Alfred Center are being expended annually toward deter-
mining the cause of YTD and developing effective control measures.













-13-


THE POSSIBLE USE OF NEOHESPERIDIN DIHYDROCHALCONE AS A SWEETENER IN
GRAPEFRUIT JUICE--Paul J. Fellers, Florida Department of Citrus.

It may be desirable now or in the future in certain instances
to sweeten grapefruit juice or other citrus products using a non-
nutritive sweetener. With the apparent demise of cyclamates, only
saccharin remains to do the job, and saccharin itself is under heavy
attack. A Florida Department of Citrus Market Research Report
(Hoffer, 1969) indicated very favorable sales and consumer acceptance
of artificially sweetened grapefruit juice in an extensive 1960 study.
Now a new non-nutritive sweetener--neohesperidin dihydrochalcone (NHD)
discovered several years ago by Drs. Robert Horowitz and Bruce Gentili,
USDA, Fruit and Vegetable Chemistry Laboratory, Pasadena, California--
is undergoing final testing for FDA approval for use by humans. NHD
has been estimated to be 1,500 or more times sweeter than sucrose on
a weight basis.

Our taste panel data has indicated an approximate threshold
level of NHD in canned single strength grapefruit juice of 6.6 ppm
or 1.14% sucrose equivalent (if NHD is considered to be 1,500 X
sweeter than sucrose). Individual thresholds in several instances
were found to vary significantly from the average. Further taste
panel studies have shown that an addition of about 8-12 ppm of NHD
to different grapefruit juices results in a significant sweetening
effect with only a slight, but acceptable amount of aftertaste.
NHD could be especially useful in upgrading the flavor of low-ratio
early-season grapefruit juice. Another use of NHD might be in re-
placement of a significant amount of natural sweetener used in cover-
ing syrups for canned or frozen sections.












-14-


QUANTITATIVE DETERMINATION OF SORBIC ACID AND SODIUM BENZOATE IN
CITRUS JUICE--Margaret H. Bennett and D. R. Petrus, Florida Department
of Citrus.

A procedure has been developed using anion exchange high pressure
liquid chromatography which is capable of determining microgram
quantities of two common food preservatives, sodium benzoate and
sorbic acid, in citrus juice. The compounds are eluted with a simple
buffer system and detected with a variable wavelength spectrophotometer.
Simultaneous determination is possible. Centrifugation and filtration
are the only sample preparation required and LC analysis time is less
than 10 minutes. Results confirmed by ultraviolet absorption and low
temperature (770F) fluorometric and phosphorimetric analyses, are
accurate and reproducible. Analysis of fortified juice samples in
the common ranges yield values within 3% of the prepared concentration.












-15-


YIELD AND QUALITY OF BY-PRODUCTS MADE FROM CULL, SPLIT, AND DROPPED
FRUIT--R. J. Braddock and J. W. Kesterson, University of Florida.

Total quantities of initial grading line rejects from a com-
mercial citrus plant were collected and brought to Lake Alfred for
processing. Rejects were taken from 4,500 boxes of midseason
(1/26/76) and 12,500 boxes of Valencia (4/14 and 5/3/76) oranges.
The fruit were washed and rinsed in the AREC packinghouse, juice
was extracted with an FMC extractor and peel oil, cattle feed and
molasses were made in our pilot plant under simulated commercial
conditions. For comparison purposes, controls were sound fruit
from the same days' run at the plant.

Cull fruit juice yields were 20% less than from sound fruit.
Concentrate made from cull fruit using cutback and peel oil from
sound fruit had a stale fruit off-flavor, but was acceptable
(Flavor Score 32-34). Total reducing sugars were higher (10%) and
vitamin C was lower (8%) in the juice from cull fruit, while color,
cloud, and viscosity were about the same as in juice from sound
fruit.

Cold-pressed orange oil made from cull fruit generally showed
adulteration from other citrus cultivars; e.g. mandarin, grapefruit,
etc. The oils had only half the aldehyde content as good quality
oils and failed to meet U.S.P. specifications. Oil recovery from
the cull fruit varied from about 3 lb/ton for midseason to 5 lb/ton
for Valencia.

Crude fat, protein, and fiber content of the cull fruit dried
pulp for cattle feed were in the same range as for sound fruit.
Molasses made from cull fruit press liquor showed higher reducing
sugars, less sucrose, and the same fat, fiber, pectin, and protein
content as that from sound fruit. However, the viscosity was from
5-10 times greater for cull fruit molasses. Dried pulp and molasses
yields were 20% greater than from sound fruit; however, more fuel
would be required to make these products because of the higher
moisture contents (88-90%) in the wet peel. Approximately 1 ton of
10% moisture dried pulp and 0.4 tons of 720Brix molasses were
recovered from 10 tons of wet peel residue.












-16-


NARINGIN RECOVERY FROM PECTIN LEACH WATER OF GRAPEFRUIT ALBEDO--
P. G. Crandall and J. W. Kesterson, University of Florida.

Samples of shaved 'Duncan' grapefruit albedo were taken every
two months from October to April. These samples were obtained from
two processing plants which use the AMC shaver. Soluble solids,
mostly sugars, are normally removed from citrus peel before the
pectin extraction or the resulting pectin will be an undesirable
brown color. The removal of the soluble solids is normally
accomplished by leaching the peel with room temperature water. In
our process, a hot water leach was used to remove the soluble solids
as well as the naringin from the peel.

Highest yields of naringin were obtained by using a 1:3 ratio
of peel to leach water at 190-1940F for 5 minutes. Yields of
naringin were further increased by concentrating the leach waters
threefold. This concentration increased the yield of the isolated
naringin by approximately 33%. The hot water leach procedure
resulted in the recovery of more naringin than did the traditional
caustic naringin recovery (2:3 ratio of peel to water) in all but
one case. On a pure naringin basis, recoveries ranged from 4.9-10.6
Ib/ton of albedo. At current prices for naringin, this would offer
a potential of approximately $1.75 per box of grapefruit.

The economic advantages of using hot water to leach pectin
peel include the recovery of naringin, an otherwise lost specialty
product, and the concentrating process produces distilled water
which can be reused in the pectin leach operation.












-17-


THE COLOR OF HIGH DENSITY CONCENTRATES AS AFFECTED BY TIME AND
TEMPERATURE OF STORAGE AND VARIETY OF FRUIT--R. L. Huggart and
D. R. Petrus, Florida Department of Citrus.

During the past two seasons there have been reports that the
orange color fades during storage of drums of concentrate packed for
the futures market. This raises a very important question, does
concentrate change color during storage?

The carotenoid pigments contribute the major part of the color
found in orange juice. Some 22 carotenoid constituents have been
reported in 'Valencia' orange juice. The colors of these pigments
depend upon the number of effective double bonds in the molecule.
Heating and/or concentrating orange juice has been reported to increase
the percentage of carotenoid esters. Non-enzymic browning has been
a color problem during storage of canned single strength citrus
juices and in grapefruit sections. The degree of injury to tissue
experienced in processing of the 'Pineapple' fruit has been reported
by Gortner and Singleton (1961) to result in a lighter color in the
product due to the formation of cisisomers of carotenoids.

To study color changes in concentrate during storage, a model
system was set up at the Center. To date, five packs of
concentrate have been prepared from known varieties of fruit using
the Center TASTE evaporator. Concentrates of approximately
60Brix, prepared from 'Hamlin,' 'Valencia,' 'Pineapple,' 'Murcott'
and 'Temple' fruit, were filled in citrus enamel lined (6 or 12-
ounce) cans, steam closed, and stored at -80, 200, and 320F. Cans
of concentrate are examined at 3-month intervals. Color
measurements are determined on samples reconstituted to 12.80Brix
using a D45/D2 citrus colorimeter. Alcoholic solutions of the
juices are scanned for absorbance characteristics in the visible
range (600 nm to 370 nm) using a Coleman Model 124 recording
spectrophotometer.

Although studies of concentrates at 200F were interrupted by
a storage cabinet failure, data obtained from samples stored at -80
and 320F show a consistent pattern of increasing Citrus Red (CR)
and lower Citrus Yellow (CY) values. Visible absorption spectra
of alcoholic solutions of reconstituted samples revealed absorption
maxima at about 465, 445, 425, and 400 nm. During the twelve
month storage period the absorbance sum for Murcott was variable
and for Valencia decreased approximately five percent at -80F.











-18-


At 320F it decreased ten and nineteen percent respectively for these
two cultivars. This indicated a loss of carotenoids with time and
temperature, and a decrease in color score should have been observed.
The available data obtained from the 20F storage which was
interrupted due to a mechanical failure revealed a trend intermediate
between -80 and 320F. Preliminary results for other varieties being
investigated indicated similar trends. The magnitude of absorption
change appeared to be time, temperature, and variety related. The
decrease in Citrus Yellow values with time and temperature appeared
to follow a decrease in visible absorption. However, the absorption
spectra did not reveal any qualitative differences to support the
increase in Citrus Red values. The absorbance ratio at 425/443 nm
vs. time of storage produced curves very similar to that of CR values
vs time. This change in ratio was consistent with slight changes in
visual color observed when -8 and 320F samples were compared by
trained observers. The -80F samples were bright yellow and darker
than samples stored at 320F which were reddish and tend to look
whiter. The net effect of the changes in objective red and yellow
color measurements resulted in the same or slightly higher color
number. Studies of visible absorbance spectra indicated that a
"browning reaction" may be occurring in the concentrate that might
mask any fading due to changes in carotenoid material. The changes
in visible absorbance of the concentrate samples were consistent
with changes reported previously by Petrus and Olsen for bottled
single-strength orange juice.

Although a study of color changes during processing and freezing
was not included in this study, it should be mentioned that freshly
extracted juices were higher in CR and CY values than were freshly
reconstituted concentrates. It was also noted that the cans of
concentrate were lighter (lower CR and CY values) in color after
they were completely frozen and reconstituted (1 to 2 weeks at -80F)
than they were when first packed before freezing. Additional studies
are planned for the next season to document the time and drop in
temperature and color changes in barreled concentrates under com-
mercial conditions.












-19-


ORANGE JUICE COLOR MEASUREMENT USING VARIOUS GENERAL PURPOSE
TRISTIMULUS COLORIMETERS--Bradley Eagerman, University of Florida.

A feasibility study comparing the Hunter D45/D2 citrus
colorimeter to some general purpose colorimeters was conducted.
Multiple regression equations with very good correlation
coefficients were found for most instruments. The advantages of
these other instruments are cost and that they can be calibrated
with flat non-fading colored tiles. The main disadvantage is the
cells used. They are more expensive and require more care in
handling than the glass test tubes.






Lake Alfred AREC Research Report-CS77-1
2/10/77-HWF-100


A PERISTALTIC PUMP FOR LIQUID CHLORINE INJECTIONS :' / /-
IN LOW PRESSURE IRRIGATION SYSTEMS

Harry W. Ford /
University of Florida, IFAS -. /
Agricultural Research and Education Center '/i/
P. 0. Box 1088 Of/o i
Lake Alfred, Florida, 33850, U.S.A.


Liquid or gaseous chlorine is the most widely used biocide for water
treatment, chlorine can be used for controlling slimes of sulfur in water
containing hydrogen sulfide, for nonfilamentous slime-forming bacteria,
for precipitating iron, and for inhibiting algal slime in drip irrigation
lines. Certain treatments must be continuous during the irrigation cycle.

Liquid chlorine is the preferred treatment if pumping rates are less
than 200 gpm. Liquid chlorine is corrosive and may contain particulate
matter. A peristaltic type pump has no valves or parts subject to corrosion
within the flexible plastic line. A durable continuous duty peristaltic
type pump is rated primarily by the life of the tubing which must be changed
or the tube shifted in the pump at intervals depending on rpm and duration
of pumping. The principal advantage is that particulate matter that passes
through the line will not clog the pump.

There are a number of pumps of the peristaltic type on the market and
some of them have variable speed control; however, in tests, motor failures
at low rpm were common. A frequent complaint with variable type pumps,
with or without valves, has been fluctuations in rates of chlorine injection
that may go undetected. Most good quality pumps cost more than $250.

The units constructed at AREC, Lake Alfred consist of Dayton brand
motors with gear reductions rated for continuous duty and costing about
$42. The 1/20 hp motors are available with outputs of different rpm
values, up to 30 rpm. It has been found that the stated rpm should be
checked because units listed at 2 rpm are actually running at 2.33 rpm.
The 6 rpm motors are running at 7 rpm. The maximum 10% NaOC1 that can be
injected would be 30 ppm in a water line flowing at 100 gpm (30 rpm motor).

The pump heads are Masterflexz brand plastic units available in 6 sizes.
Each head costs about $40. Use only Tygon tubing 6408z or Viton tubing 6412z
in the pump. Silicone plastic tubing 6411 is unsatisfactory. The pumps
should not be used on irrigation systems with line pressures above 20 psi.
Protect Tygon tubing from sunlight to reduce the rate of deterioration.


A Florida source for Dayton motors: Grainger, Inc., Tampa, Fla. This is
a wholesale outlet so that several retailers handle Grainger products,
phone (813) 253-5316. There are probably other motors on the market that
could be adapted for use.

ZSource of the Masterflex pump heads. Cole-Parmer, Inc., 7425 North Oak
Park Ave., Chicago, Ill. 60648, phone (312) 647-0272. They are also
available from scientific supply outlets. Tygon and Viton tubing may
have different numbers.






A Peristaltic Pump... -2- Harry W. Ford
Research Report-CS77-l



Pumping rates in relation to motor rpm and pump head sizes are shown
in Table 1. A method for estimating chlorine requirements is published in
the Proc. Fla. State Hort. Soc. 89, 1976, and is also available from the
author. Chlorine chemistry is complicated.


Formula for ml/min of 10% NaOCl: 0.03785 x (ppm of desired chlorine)
x (gpm irrigation pumping rate)

Formula for ml/min of 5.25% NaOCl: 0.07209 x (ppm of desired chlorine)
x (gpm irrigation pumping rate)

The construction of the adaptor unit (D, E, and F) for coupling the
Masterflex pump (A and AA) to the Dayton motor (G) is shown in Fig. 1.
The spider coupler (C) can be purchased and should be 1/2" on the pump end
and 5/8" on the motor end. A forked shaft (B) can be cut from 1/2" rod.
The spacers (E) are cut from wood or metal. Templates for constructing the
adaptor plates (D and F) are in Fig. 2.






A Peristaltic Pump... -3- Harry W. Fora
Research Report-CS77-1











Table 1. Pumping rates for 2, 6, 12, and 30 rpm Dayton motors coupled to
different numbered Cole-Farmer Masterflex add-on pump heads.


SHours esti- Hours esti-
Dayton general purpose mated life of mated life of
Add-on pumpger motor Tygon 6408 Viton 6412
Cole-Parmer 2 rpmx 6 rpmx 12 rpm 30 rpmy tubing tubing
head number ml/min ml/min 'ml/min ml/min 7 rpm 30 rpm 7 rpm 30 rpm

7013-20 0.14 0.42 0.72 1.80 3800 886 2300 536

7014-20 0:52 1.43 2.45 6.12 3800 886 2300 536

7016-20W 1.92 5.40 9.25 23.10 3600 857 2200 523

7015-20W 3.90 11.90 20.40 51.00 3300 785 2000 476

7017-20 6.20 19.30 33.10 82.70 3000 714 1800 428

7018-20 8.80 26.00 44.50 111.42 2500 595 1500 357


W7016 and 7015 are not reversed.


XActual rpm of the motors was 2.33 and 7.0 rpm, respectively.

Yml/min are from data supplied by Cole-Parmer since the 12 and 30 rpm motors

have not been tested in the field or on our laboratory test rig.


.. .. -






A Peristaltic Pump...
Research Report-CS77-1


Harry W. Ford


Fig. 1. Pump head coupled to low rpm motor.




Fig 2 TEMPLATE MADE OF 16 GUAGE SHEET METAL


2 1/2 x 5


BLOCKS


OF WOOD TO SECURE


TEMPLATES TOGETHER


1/4 HOLES (3)


3/16"


USE (2)3/4 to