Note: Descriptions are shown in the official language in which they were submitted.
~,2~3~
APPARATUS FOR INCUBATING PHASE EGGS
Technical Field
This invention relates to an apparatus for lncu-
batting fish eggs and, more particularly, to a compact,
energy and cost efficient apparatus for incubating product
lion quantities of a variety of kinds of fish eggs
Presently. large items of equipment protected by
appropriately sized buildings are used to hatch fish eggs.
The small fish or fry are then transported to a stocking
location. The present apparatus replaces this type of
capital investment with a portable apparatus opera table
with batteries for aerating and recirculating water
through the incubating fish eggs. The apparatus itself
can be used to transport eggs or fry.
Background of the Invention
Known production fish hatcheries represent a
large capital investment. They have stationary locations
and include costly high-volume pumps, large filtering
systems, water heaters, large tanks and a variety of
accessory equipment. All of -these items are ordinarily
housed in one or more buildings. In addition, known fish
hatcheries use relatively large quantities of water. It
is common for a hatchery to use 600 volumes of water per
volume of eggs per day. For example, in a conventional
Wylie hatchery, it is no-t uncommon to circulate more
than one million gallons of water through 500 quarts of
eggs during a fifteen day incubation period. A similar
volume of coregonid eggs incubated for a hundred and fifty
days uses more than ten million gallons of water. Thus,
even though hatcheries are often operated only a few weeks
each year, the massive ecluipment must be permanently
housed in special buildings, and the buildings must be
restricted to sites having an adequate source of suitable
surface or ground water.
:
03i~
Laboratory hatching systems are in star con-
tryst to -the presently known production hatcheries. These
systems tend to be small and are utilized to incubate only
small quantities of eggs. An example of this type of
system uses a twenty litter, insulated bucket to maintain
subunit containers in a common, temperature-controlled
water bath. Compressed air, distributed by an air stone,
transports oxygenated water from a biological gravel
filter up a narrow pipe. The overflowing water causes the
water level to rise in a surrounding pressure tube. The
resulting overpricer forces the oxygenated water to pass
through connection tubes from the pressure tube to the
walls of the subunit containers. Water from the subunit
containers returns to the gravel filter for recirculation.
The subunit containers are typically on the order of 7
centimeters in diameter and 1 centimeter high. During
incubation, dead eggs are removed from -the system using a
pipette. Water is recirculated as described and exchanged
approximately every -thirty minutes. The system is suffix
ciently small that a number of samples using different water salinities or other varying parameters may be tested
efficiently.
Prior to the present invention, it has not been
possible to use laboratory type systems on a production
scale. Thus, there has been a distinct need for an index-
pensive, portable, production incubation system.
Summary of the Invention
The present invention is directed to an appear-
tusk for incubating fish eggs. The apparatus includes a
plurality of tubes having first and second ends. Each
tube is for holding a quantity of fish eggs. The appear-
-tusk includes means for containing the first ends of the
tubes in water. Water source means provides water con-
disavow to an incubating environment. The water source
means includes pressure means for causing the water to
flow. The apparatus further includes manifold means for
1~Z03~39
--3--
distributing the flowing water through the first ends of
the tubes. In -this manner, the water flows from the first
end of the tubes toward -the second end under the pressure
of the pressure means thereby flowing through and cleans-
ivy and providing dissolved oxygen for the quantity of incubating fish eggs.
In a preferred embodiment, the apparatus for
incubating fish eggs includes an insulated container
having an approximately rectangular cross-section. The
incubation container is ordinarily elevated on legs suffix
ciently long to locate an air pump beneath it. The air
pump may be energized with either alternating or direct
current sources. A plurality of -tubes are located within
the incubation container. The -tubes are preferably square
for greater egg capacity and a reduced ratio of water to
eggs in the system. Each tube has a plug at its bottom
with a centered opening. A screen covers the opening near
the upper surface. Incubating fish eggs within each -tube
rest on the plug and are prevented from falling through
the opening by the screen. The upper end of the tube has
a frame-like retaining structure with a perimeter similar
to that of the tube. A screen is attached to all sides of
the structure to form an upper screened portion with a
shape similar to the tube.
The preferred apparatus includes a fluid circuit
for recirculating water. A water source fills the con-
trainer to the required water level and partially replaces
recirculated water throughout incubation. A drainage
valve is located near the bottom of the incubation con-
trainer.
A vertically-oriented air lift tube external to
the incubation container rises from a tube connected
between the incubation container and the water source. An
air line from the air pump is installed in such a manner
as to exhaust air through a diffuser near the lower end of
the air lift tube. Since the air lift tube is in fluid
~L;~2~38~
communication with the water inside the incubation con-
trainer, the air lift tube is ordinarily filled with water.
The bubbling air from the air diffuser lifts water in the
air lift tube into a tank above the tube. The lifted water
provides a pressure head for forcing water throughout the
fluid circuit.
Proximate the air lift -tube and tank there above
is a filter element or cartridge. The upper end of the
filter element has a handle so the filter may be easily
lo removed and replaced within its housing. The lower end of
the filter element is open and fits about a short -tube
extending above a manifold chamber. Water from the pros-
sure head -tank is communicated -to the filter element. The
water passes through the filter element wall and is -then
forced into the manifold chamber a-t the lower end of the
incubation corrtainer.
The manifold chamber is comprised of an enclosed
housing having a perimeter similarly shaped but somewhat
smaller than the interior perimeter of the incubation
container. The upper wall of -the manifold chamber has a
plurality of nipple elements regularly spaced thereon.
The openings in the plugs in the lower ends of the incubi-
lion tubes mate with the nipple elements of the manifold
chamber. Thus, the incubation tubes are held in place by
-the nipple elements. As water is forced from the manifold
chamber through -the nipple elements into the incubation
tubes, the incubating fish eggs are cleansed and provided
with oxygen in the flowing water. The water flows from -the
lower end of the tubes to -the upper end to form a water
level common with all the tubes a-t a height above the
bottom of the vertical screens. In the recirculating
mode, water then is drawn downwardly between the incus
bating tubes and out an exhaust pipe through a valve to a
tee connecting with the air lift tube and water inlet
valve.
22~3~
-5
Although it must be emphasized that container
and tube dimensions may vary, approximately two quarts of
eggs can be incubated and hatched in a tube which is two
and one half inches square and 39 inches in length. That
is, approximately 5.75 million Wylie eggs may be incus
bated and hatched in an incubating apparatus having 24
incubation tubes and one filter housing -tube.
When the incubating apparatus is operated with-
out recirculating water, then external water flows con-
tenuously prom the water source. The water flus up the
air lift -tube, being pushed by the pressure from the water
source, through the filter element and manifold chamber to
cleanse the eggs. The water then exhausts from the
screened portion at -the upper ends of the incubating tubes
through an outlet overflow tube in -the upper wall of the
incubating container. When the incubating apparatus is
operated in the more usual water recirculation mode, then
the air or oxygenating source is required -to provide both
new oxygen to the water and flow energy by lifting water
Pinto the pressure head tank.
Incubating fish eggs require adequate oxygen,
appropriate water temperature and removal of metabolic
waste materials, primarily ammonia and carbon dioxide.
Preferably, air is bubbled into the air lift tube at a
rate to oxygenate the water to near saturation and to
drive off carbon dioxide. Heating apparatus with appear-
private controls Iceeps water temperature in an optimal
range, generally 40 F to 60 F depending on fish species.
The rate of flow of water from the water source into the
system must sufficiently remove metabolic wastes and also
prevent water temperature from rising to an unacceptable
level due to heat gain from ambient room temperature.
Ordinarily, flow rate can be lesser during early incubi-
lion and must be increased in the later stages and at
hatching.
2~38~
--6--
Thus, the present incubator apparatus is par-
titularly advantageous since the initial cost for primary
and accessory equipment is much less than that needed for
a contemporary stationary hatchery. The compact size
considerably reduces capital investment and the reduced
water requirement increases incubating versatility.
Special buildings for housing equipment are unnecessary
or, a-t least, much reduced in size and expense. The incus
baton apparatus is portable and not restricted to sites
having a large supply of surface or ground water.
The incubator apparatus has the further ad van-
tare that it may be used at different locations during
different seasons for eggs of different fish species. The
apparatus is easily moved depending on the operational
needs.
The present invention is the only known pro-
diction incubator for fish eggs that uses an air lift pump
to create a low pressure head to force water circulation
throughout the system. This is particularly advantageous
since detrimental gases are removed from the water during
the bubbling agitation in the air lift pump before the
water is circulated to the egg masses.
The apparatus is inventively simple and con-
lenient. Basically, incubation tubes are placed in a
water bath. A simple friction fit exists between a plug
at the bottom of a tube and the water distribution manic
fold. Each incubation tube may be advantageously lifted
from or placed into the recirculating watch system.
Additionally, the apparatus allows more precise
control of incubation temperatures thereby producing
healthier fry, that is, newly hatched fish, and more
versatile scheduling of hatching and fry stocking opera-
lions. The present incubator apparatus does not require a
separate fry collection tank. Hatched fry are retained in
each egg container tube thus allowing more accurate allot
~.Z2~3~
--7--
mint of fry stocking quotas. Less time and effort of
hatchery personnel is required, and -the fry are subjected
to reduced handling stress.
With the present incubation apparatus, applique-
-lion of fungicides for prophylactic treatment and intro-
diction of other reagents is more simply administered. In
addition, the materials required are greatly reduced.
Since many other advantages and objects obtained
by the use of -this important invention exist, reference
should now be had to the drawings which form a further
part hereof and to the accompanying descriptive matter in
which there is illustrated and described in greater detail
a preferred embodiment of the invention.
Brief Description of the Drawings
FIGURE 1 is perspective view of an apparatus in
accordance with the present invention;
FIGURE 2 is a top view of the apparatus shown in
FIGURE l;
FIGURE 3 is a cross-sectional view, taken along
line 3-3 of FIGURE l;
FIGURE is a partially exploded view of the
upper screened portion of an incubation tube;
FIGURE 5 is an exploded view of the lower port
lion of an incubation tube as it mates with the manifold
chamber;
FIGURE 6 is a cross-sectional view of an incubi-
lion tube properly located with respect to the manifold
chamber;
FIGURE 7 is a cross-sectional view of the pros-
sure head tank and the filter housing assemblies;
FIGURE 8 is an exploded view of the lower port
troll of the filter housing as it mates with the manifold
chamber;
FIGURE 9 is a cross-sectional view of the filter
housing as i-t mates with the manifold chamber;
SUE
--8--
FIGURE lo is an exploded, cross-secticnal view of
an alternate embodiment of a plug and nipple configuration,
FIGURE lo being found out of order on sheet 1 of the drawings
with FIGURES 1-2,
FIGURE if is a cross-sectional view of an alternate
embodiment showing air lift and drainage features; and
FIGURE 12 is an exploded view of an incubation
tube.
lo Detailed Description of the Invention
__ __
Referring now to the drawings, wherein like
reference numerals designate identical or corresponding parts
throughout the several views, and, more particularly, to
FIGURE 1, an apparatus for incubating fish eggs in accordance
with the present invention is designated generally as 20.
Apparatus 20 is comprised of a container 22 which holds a
plurality of tubes 24. A number of other elements are inter-
connected with tubes 24 to form a fluid circuit for running
external water there through or for recirculating continually
oxygenated water therein.
In a preferred embodiment, incubating container 22
is essentially an open-ended, insulated box 26 on legs 28.
Box 26 may be square or it may have other dimensions, for
example, rectangular cross-sectional dimensions. The lower
end of the box is insulated, as shown in FIGURE 3, while the
upper end is open. The height of box 26 is determined by the
length of tubes 24 and the optimal water level to be main-
twined within container 22 during the incubation process.
Box 26 is insulated in order to maintain the water them-
portray therein at a relatively uniform and constant level.
In warm environments, the insulation aids in keeping the
water cool thereby reducing a need for cooling make-up water.
Zig
- 9 -
part of a separate framework 30 on which box 26 is sup-
ported. As shown in FIGURE 3, framework 30 includes a
weldment 32 of four box-section members to form a square.
Four legs 28 are welded to extend downwardly from the
weldment 32. Various types of commonly known retaining
apparatus, not shown, may be used to hold box 26 to frame-
work 30.
manifold chamber 34 having a similar but
slightly smaller shape than the internal shape of incus
bating container 22 rests on -the bottom surface of in-
cubating container 22. The water distribution function of
the manifold chamber 34 as a part of a fluid circuit is
discussed hereinafter. As shown in the embodiment of
FIGURES 3 and 6, manifold chamber 34 is comprised of
spaced-apart -top and bottom plates 36 and 38, respect
lively. Side plates 40 extend between the two plates 36
and 38 at the edges thereof to form a water-tight enclo-
sure. A plurality of nipple elements 42 project through
openings 43 in top plate 36 (see FIGURE 6). Nipple eye-
mints 42 have a frusto-conical shape with an axial Solon-
Dracula opening 44. Nipple elements 42 have a flange 46
extending around the base portion of the elements 42.
Nipple elements 42 are fastened with an adhesive, screw,
or other mechanism such that flange 46 is retained along
the underside of top plate 36. Nipple elements 42 extend
above the upper surface of top plate 36 sufficiently to
retain plug 48 which is fastened a-t -the bottom end of a
tube 24 as described hereinafter. Nipple elements 42 do
not extend through plug 48 but rather remain a short
distance below the upper surface of plug 48. Note that,
as indicated by the alternate embodiment described here-
inciter, elements 42 are not limited to the presently
described shape.
The dimensions of tubes 24 correspond suffix
ciently with the inside dimensions of container 22 such that a desired number of tubes 24 may compactly fit within
~2Z~389
-10-
container 22 and fill the entire space in an appropriate
manner. Tubes 24 are uniformly spaced from each other and
from the inside wall surfaces of container 22 as shown in
FIGURE 2. The spacing between adjacent tubes 24 and the
Allis of container 22 is sufficient -to allow the tubes to
be lifted vertically from the container. All tubes 24 are
substantially the same except that one space where a tube
24 might otherwise be located is filled by filter housing
52 described hereinafter. In alternate embodiments, in
particular an embodiment described hereinafter, one or
more tubes 24 may be replaced with an assembly taking the
place of air lift tube 86. In such embodiments, exhaust
pipe 50 through the wall of container 22 may be eliminate
Ed
A tube 24 is comprised of upper and lower port
lions 54 and 56, respectively. Lower portion 56 is pro-
fireball a standard square -tube. As shown in FIGURES 5 and
6, ply 48 matches approximately the internal dimensions
of lower portion 56 of tube 24. The upper surface 58 of
plug 48 has a concave pyramid shape with a flat portion
near the peak. A frusto-conical opening 60 is centered in
plug 48 and matches the shape of the upper portion of
nipple elements 42. A screen 62, for preventing fish eggs
from dropping through openings 60 and 44 into manifold
chamber 34, covers the upper end of opening 60 and is
fastened to plug 48. Plug 48 is of molded rubber or
silicone material. It forms a friction fit into or is
otherwise fastened to the lower portion 56 of tube 24.
Plug 48 is removable to facilitate washing of lower port
lion 56 and to allow plugs of various designs to be ox-
changed to provide suitable water flow for eggs of various
fish species. Since opening 60 mates with nipple element
42, tube 24 is located and retained at its lower end by
allowing nipple element 42 to project into opening 60.
The concave design shape of the upper surface 58 of plug
48 helps to move the water so as to provide oxygen and
~2~)3i~3
cleanse the fish eggs of a particular species as the water
flows upwardly from the lower end of tube 24 toward the
upper end.
As shown in the er~odiment of FIGURES 3 and 4,
the upper portion 54 of a tube 24 is comprised of a no-
twining structure 64 covered with a screen 66. Retaining
structure 64 has the same outer envelope as the lower
portion 56 of tube 24. However, large open windows 68 are
Cult in each side of what would otherwise be a square tube.
Approximately half the thickness of each side of the lower
end 70 of upper portion 54 is machined away. In a similar
fashion, the inner sides of the upper end of the lower
portion 56 of tube 24 is machined. In -this way, upper
portion 54 may be inserted into lower portion 56 to mate
tightly together. Screen 66 is fastened to the inside of
retaining structure 64 so as -to cover windows 68 and to
extend a short distance above retaining structure I
Toward the end of an incubation period when eggs
hatch, the egg shells tend to rise and become caught in
screens 66, while the fry tend to remain midway in tubes
24. Upper portions 54 of tubes 24 are easily removed and
cleaned of egg shells if necessary. Additionally, upper
portion 54 is removable from lower portion 56 when pouring
fry from a-tube 24.
The incubating apparatus 20 in accordance with
this invention includes a fluid circuit which not only may
accept external water for flowing through and cleansing
the fish eggs in tubes 24 and exhausting out overflow tube
76, but also provides an optional continuous fluid pathway
for complete recirculation of a given amount of water
within apparatus 20. An air source is available for
providing air to oxygenate external water or recirculated
water as required and also to provide flow energy to
recirculated water.
A water source, not shown, communicates water to
inlet valve 78 as seen most clearly in FIGURE 3. Alterna-
:~2~3~3~
12-
lively, of course, water may be introduced through -the top
of container 22. When the valve 78 is open, water flows
through connecting tube 80 to -tee 82. The side of tee 82
opposite connecting tube 80 is connected through a check
valve 84 to exhaust pipe 50 in the wall of incubating
container 22. Check valve 84 is oriented -to allow water
-to exhaust from incubating container 22 while preventing
aver from entering. Air lift tube 86 is connected to the
upright portion of tee 82. The upper end of air lift tube
86 connects-to water pressure tank 88.
Air from the air system is inserted through the
bottom of tee 82 into air lift tube 86. The air system
includes an air pump 90 attached, for example, with nut
and bolt combinations 92 -to support framework 30 of incus
batting container 22. Air pump 90 is connected to -tee 82
-through regulator valve 94 and check valve 96 by tubes 98,
100 and 102. Tube 102 extends through the bottom of -tee
82 and is sealed thereto to prevent water leakage. The
upper end of tube 102 extends into air lift tube 86 or, at
least, into -the upper portion of tee 82. An air stone or
air diffuser 104 is fastened to the upper end of tube 102.
Thus, as air is expelled from -tube 102, it is diffused
in-to small bubbles which rise in air lift tube 86 to lift
water upwardly into -tank 88. The flow of air must be
sufficient to supply adequate oxygen for embryo develop-
mint. In addition, -the flow of air and the inside die-
meter of air lift tube 86 must be sufficient to provide a
lifting of sufficient water to establish the required
pressure head in tank 88.
Tank 88 is located approximately vertically
above air lift tube 86. The bottom of tank 88 is approxi-
mutely a-t -the same vertical level as the top of incubating
container 22. In this way, a pressure head of a few
inches may be created. As shown in FIGURE 7, air lift
tube 86 is fastened by a double nut union 106 to the
bottom of tank 88. A short extension tube 108 extends air
2Q~
lift -tube 86 a short distance inside tank 88. Tank 88 is
open -to the atmosphere at its upper end. A foam free-
shunter cup 110 is installed at the upper end of tank 88.
Foam fractionators are commonly known and are ordinarily
comprised of a cup having an opening in the bottom with
upwardly extending flanges around the opening. A foam
fractionator functions by allowing foam to pass upwardly
through the opening and expand toward the walls of -the
cup. The upwardly extending flange prevents the foam from
receding through the opening. Hence -the foam is captured
and removed from the fluid circuit. Organic wastes are
removed in the foam.
The lower portion of tank 88 is in fluid come
monkeyshine with the upper end of filter housing 52. A
double-threaded union 112 may be used to thread into
threaded openings 114 and 116 in tank 88 and filter house
in 52, respectively. The upper end of extension tube 108
is above opening 114. A screen 118 is retained at a level
between the upper end of extension tube 108 and opening
114. Screen 118 functions to prevent large particulate
matter from entering filter housing 52.
As shown in FIGURES 1 and 2, filter housing 52
is preferably a round tube. Filter housing 52 extends
above incubating container 22. An overflow tube 120
protrudes from the upper wall of filter housing 52 at a
level above opening 116. Overflow tube 120 is oriented to
direct water back into the upper portion of incubating
container 22. Overflow tube 120 functions only if water
cannot pass through filter 122 sufficiently fast so that
water rises in filter housing 52 to the level of overflow
tube 120.
As shown in detail in FIGURE 8, the lower end
124 of filter housing 52 has scalloped portions 126 and
128. Scalloped portions 126 and 128 are simply arcuate
cutaways from end 124 of filter housing 52 which allows
passage of water to exhaust pipe 50. A filter housing
~'~Z038~
-14-
plug 130 is comprised of a short tube having an outer
diameter slightly smaller than the inner diameter of
filter housing 52. Plug 130 has an upper cover 134 with a
centered opening. Plug 130 also has scalloped portions
136 and 13~ which match the scalloped portions 126 and 128
of filter housing 52. Plug 130 is sufficiently long to
extend from the lower end 124 of filter housing 52 to
above the scalloped portions 126 and 128. Plug 130 is
fastened by adhesive, screws or other fastening mechanism
-to filter housing So.
Filter housing 52 rests on manifold chamber 34.
As shown in FIGURES 8 and 9, a relatively small diameter
tube 140 passes through an opening in the top 36 of manic
fold chamber 34. Tube 140 is held in place by an apt
propriety fastening mechanism such as a pair of nuts 144,142, one on either side of top 36. Cover 134 of plug 130
has an opening 146 centered therein. Opening 146 is
slightly larger than the diameter of tube 140. Hence, the
lower portion of filter housing 52 is held in place by
tube 140 passing through opening 146 of plug 130 which is
fastened to the lower portion of filter housing 52.
In addition -to -the above description, it is to
be understood that filter 122 may have various formed
shapes or be an accumulation of a material. Also it may
be comprised of a variety of different materials. In
situations where a water source is limited (for example,
in transit), filter 122 may be comprised of natural zoo-
file minerals. Natural zealot minerals are comprised
essentially of alumina silicate, crystallized into Milwaukee-
far sized cavities connected by a series of channels Natural zealots have the ability to ion-exchange with
certain ions. The preferable natural zealot mineral
clinopt.ilolite has the ability to adsorb unionized
ammonia, NH3, and ion exchange ammonia ion NH4. Thus,
ammonia levels would be reduced to a level non-toxic to
fish. Hence, in this case, in combination with the water
~ZZ~)3~
-15-
oxygenation function of the air system, the filter 122
would renew the water and continually keep it conducive -to
egg incubation. Once the clinoptilolite has been sub Stan
tidally loaded with ammonia, the filter cartridge may be
removed and replaced by a regenerated cartridge. Cleanup-
tilolite is regenerated in a saline solution.
The filter 122 is preferably cylindrical in
shape. The outer diameter should be sufficiently small to
fit within filter housing 52 and allow space between the
inside wall of housing 52 and -the outer surface of filter
122 for -the accumulation of water. The inner diameter
should be slightly larger than tube 140 so that tube 140
may be received within the open lower end of filter 122.
At -the same time, -the fit of filter 122 about tube 140
should be reasonably tight to prevent any significant
amount of water from by-passing the filter before passing
through tube 140 into manifold chamber 34. The upper end
of filter 122 is threaded or otherwise has a handle 148
fastened to cover the cylindrical opening. Handle 148
allows easy removal and replacement of filter 122. The
upper end of filter 122 is located a short distance below
opening 116. As water enters filter housing 52 from tank
83, it flows downwardly around the sides of filter 122.
The water is forced or otherwise drawn through filter 122
and continues to flow downwardly through tube 140 into
manifold chamber 34. From manifold chamber 34 the water
is forced upwardly through nipples 42 into tubes 24 as
described herein before.
alternatively, filter 122 may be shaped to
accept incoming water between the walls defined by the
inner diameter. With the bottom end of filters 122 cover-
Ed the water would pass through filter 122 to -the space
between filter 122 and filter housing 52 before entering
tube 140. In this case, of course, -tube 140 would not be
received in the lower end of filter 122. With such a
~2~C~3~39
-16-
shape, since the particulate matter would be retained
within filter 122, particulate matter would be removed
when filter 122 is removed.
Exhaust pipe 50 is a par-t of the fluid circuit
and, during recirculation, is the usual mechanism by which
water leaves incubating container 22. There are, however,
other ways for water to exhaust from incubating container
22. Container 22 is drained through tube 150 and
valve 152 located in the wall of incubating container 22
approximately at the same level as the top of manifold
chamber 34.
Overflow water exits through -tube 76. Discharge
tube 76 is located in the wall of incubating container 22
near its upper edge. When the incubator is operated with
input valve 78 closed -there is no discharge through tube
76. With input valve open or partially open, water is
discharged through tube 76 in volume equal to inflow
volume.
The water temperature in incubating container 22
may be monitored and controlled by a commonly known then-
mostatic control 154 (see FIGURE l). Thermostatic control
154 is electrically connected with heat tape 156 which is
wrapped about air lift tube 86. The heat tape is powered
by either an alternating or direct current source (not
shown). The thermostatic control 154 keeps the water in
individual containers 22 at a relatively uniform and
optimal incubating temperature. When a number of in-
dependent recirculating incubators 20 are operated Somali-
tonsil, separate temperature controls 154 provide
versatility so as to control the rate of egg development
and hatching in the various lots of eggs. As indicated
herein before, make up water commonly provides cooling. A
heating system provides the versatility of heating if
necessary or desired.
~;~;20389
-17-
In operation, a filter element 122 is installed
in filter housing 52. Tubes 24 are installed within in-
cuba-ting container 22 by placing the frusto-conical open-
ins in plugs 48 over nipples 42.
Air regulator I is appropriately adjusted. Air
pump 90 is started so that air is being diffused in air
lift tube 86. With drain valve 152 closed, input valve 78
is opened. Water begins filling incubating apparatus 20.
The water flows through input valve 78 and tube 80 to tee
82. Check valve 84 does not allow the water to pass
immediately into incubating container 22. Rather, -the
water flows upwardly through air lift tube 86 into -tank
88. From tank 88, the water flows -through union 112 into
filter housing 52. The water passes -through filter 122
downwardly through tube 140 in-to manifold chamber 34.
From manifold chamber 34, the water passes through the
plurality of nipples 42 through screens 62 into tubes 24.
When water flows out tube 76, input valve 78 is adjusted
to supply sufficient water to maintain the desired them-
portlier and to control the accumulation of metabolic wastes during egg incubation.
Fish eggs to be incubated are poured into tubes
24 while the incubator is operating in a recirculating
mode. The water level in each tube 24 is common through-
out incubating container 22 since water can freely pass
through screens 66. The water flows downwardly between
-tubes 24 toward filter housing tube 52. The water is
drawn by the decrease in pressure near exhaust pipe 50
resulting from water being lifted in air lift -tube 86 due
to the bubbling air. The water flows through scalloped
portions 126 and 128 of filter housing 52 and scalloped
portions 136 and 138 of plug 130. The water continues to
flow through exhaust pipe 50 and check valve 84 into tee
82. The air bubbling through diffuser or air stone 104
lifts the water in air lift tube 86 into tank 88 where -the
water is at a higher level than the level in incubating
~Z20389
-18-
container 22. Hence, the water in tank 88 has a pressure
head relative to the water in incubating container 22.
Water is forced from -tank 88 through union 112 into filter
housing 52. The water continues to be forced downwardly
through filter 122 and -tube 140 into manifold chamber 34.
As explained herein before, the water once again passes
through the various nipples 142 into the various incus
bating -tubes 24. As the water flows into tubes 24, it
spreads throughout the cross-section of tubes 24 to pro-
vise oxygen and cleanse the fish eggs as it flows upwardly
in the recirculation path.
During recirculation, -the air from air pump 90
continually oxygenates -the water. Foam developed by the
air lifting the water to tank 88 is captured in foam
fractionator cup 110. Particulate matter is removed from
the water by filter 122. Water temperature is controlled
within a narrow optimal incubating range depending on the
type of fish eggs incubated by thermostatic control 154
which controls heat tape 156 wrapped about air lift
tube 86.
Incubating apparatus 20 can also be operated in
a non recirculation mode in the event of a breakdown of
the recirculation system or in flushing the apparatus
following treatment with a fungicide. This is accom-
polished with the air source turned off and with input
valve 78 open to flow sufficient water through incubating
tubes 24. Water is discharged through -tube 76 without
being recirculated.
It is desirable to periodically clean portions
of incubating apparatus 20. In particular, it is desire
able to remove upper portions I of incubating tubes 24 to
remove -the larger particulate matter such as egg shells
and other waste caught in the screens. It is also desire
able to periodically replace the filters 122 with clean
cartridges. It is also desirable to periodically clean
~22~3~
-lug-
foam fractionator Cup 110 and screen 118. After each
incubation of fish egos, the entire apparatus 20 should be
thoroughly cleaned
An alternate embodiment for a number of elements
of incubator 20 are shown in FIGURES 11 and 12. Primed
numerals indicate similar elements between the alternate
embodiment and the embodiment described herein before. A
container 22' is shown with insulation 160 used to main-
lain a reasonably constant temperature therein as in-
dilated herein before. Drainage valve and -tube 152 and 150
and overflow tube 76 of the previous embodiment are no-
placed in the alternate embodiment with stand pipe 162.
Stand pipe 162 is comprised of tubular upper and lower
portions 164 and 166. Lower portion 166 fits within an
elbow 168 which opens to the exterior of container 22'.
I-t is the most efficient use of space to scallop a portion
of insulation 160 in a wall of container 22' adjacent -to
airlift mechanism 170 for locating stand pipe 162 -to pro-
vent from decreasing usable incubating space.
The upper portion 164 of stand pipe 162 is disk
connectable from lower portion 166 and thus replaceable
with other lengths. Since it is desirable -to periodically
drain container 22', it is necessary to remove stand-
pipe 162 from elbow 168 to allow drainage. It is con-
lenient to provide a remote puller 172 attached at one end
to lower portion 166 and extending above container 22'.
Airlift mechanism 170 includes a head tube 174
inside a sleeve 176. There must be space for water flow
between tube 174 and sleeve 176. A tube 178 for directing
pressurized air to bubbler ring 180 near the bottom of
tube 174 and sleeve 176 extends upwardly, preferably along
the outer surface of airlift tube 176. Tube 174 rises to
an elevation somewhat above the desired water level within
container 22'. Tube 174 includes an upper screened port
lion 175. It is convenient for the top end of the screened portion 175 to be formed as a removable screened
~2~3~3~
-20-
cup 177. The bottom end of tube 174 is plugged in a
fashion similar to the incubator tubes. In this fashion,
water may pass through the plug to manifold 34'. The
bottom end of air flow tube 176 has scalloped portions 182
for entry of water. Bubbler ring 180 is located in the
space between tubes 174 and 176 immediately above seal-
loped portions 182. As bubbles are emitted from bubbler
ring 180, -they rise vertically in the space between
tube 174 and sleeve 176 thereby creating water flow and in
fact lifting water. An appropriate flow of air will lift
water a distance above the water level in container 22' to
allow it to enter head tube 174 thereby creating a slight
pressure head as compared to the retainer of the water in
container 22'. The pressure head is sufficient to force
water downwardly through head tube 174 into manifold 34'
for circulation as hereinbeEore described. The upper
screened portion 175 of head tube 174 excludes most air
bubbles -thereby ensuring -that water entering head tube 174
is more dense than that with the bubbles. The screening
of portion 175 tends to catch fry or eggs accidental
spilled from any incubation tubes for removal from the
system, or it alive, for replacement in incubation tubes.
A foam fractionator device 184 is installed on
top of airlift sleeve 176. Foam fractionator 18~L includes
an upper tubular portion 186 attached to a somewhat en-
tanged connector 188 which slips over the top of
sleeve 176 thereby allowing tubular portion 186 to rest on
sleeve 176 and be retained by connector 188. There is an
opening 190 in the wall of tubular portion 186 facing
stand pipe 162. A wall 192 rises diagonally upwardly from
a lower end of opening 190. Wall 192 is attached at three
sides but does not reach the wall of tubular portion 186
opposite opening 190. In this fashion, foam from the
airlifted water may rise above wall 192 and slide down-
warmly on wall 192 through opening 190 into stand pipe 162.
2:~3~3~
-21-
In FIGURE 12, an alternate embodiment of an
incubation tube 24' and bottom plug 48' is shown. In-
cubation tube 24' is preferably a square tube. At its
upper end a plurality of screened openings 196 are formed
on two abutting sides for a purpose -to be explained here-
inciter. A screen 198 having a shape similar, but slightly
smaller, than tube 24' fits in the upper end of tube 24'
so as to cover openings 196. The lower end of screen 198
preferably includes a rubber seal 200. The upper end of
lo screen 198 preferably has a rim 202 extending thereabout
to prevent screen 198 from falling into tube 24'. Note
that screens 197 are fastened to the external surface of
tubes 24' to prevent particulate matter from flowing
through openings 196 while screen 198 is removed for
cleaning.
Bottom plug 48' includes a coupler 204 having an
upper portion 206 slightly smaller than -the internal shape
of -tube 24' to allow tube 24l to slip frictionally there-
over. Lower portion 208 of coupler 204 includes a
shoulder 210 there within against which a perforated
plate 212 is retained by bottom sleeve 214. Sleeve 214
fits tightly within lower portion 208. A bottom plate 216
covers the bottom end of sleeve 214 and includes a rubber
grommet 218 for fitting about a nipple 42' like in FIG-
USE 10. Perforated plate 212 prevents fish eggs from dropping through the opening in grommet 218 into manic
fold 34' and also disperses water flow through -the eggs
and fry.
Incubator tube 24' includes some particularly
advantageous features. The purpose of insert screen 198
is to retain egg shells during hatching. Since the fry do
not ordinarily rise to the levels of openings 196,
screen 198 may be periodically removed and cleaned of the
egg shells and other debris. This may be done without
removing -tube 24' from nipple 42'. When it is desired to
remove tube 24' and transfer fry or eggs, the tube may be
:~2~:)38~
-22-
easily pulled from nipple 42'. The eggs or fry are pro-
vented from falling by perforated plate 212. By forming
openings 19~ in only two of the four sides of tube 24',
the eggs or fry may then be easily poured along the solid
sides of tube 24'. The rapid and gentle transfer of fry
from an incubation tube 24' by pouring substantially
minimizes trauma and thus increases fry survival chances.
The various screens serve a filtering function
for particulate matter. Perforated plates 212 disperse
water flow and retain egg and fry in the incubation
tubes 24'. It is important that plates 212 not become
clogged with egg shells or other particulate matter which
may circulate with the circulating water. Thus,
screens 198 serve as primary filters to retain eggs and
fry and collect egg shells and other particulate matter as
water flows from tubes 24' into the water bath of con-
trainer I Screen portion 175 of head tube 174 excludes
most air bubbles from entering head tube 174 thereby
allowing the air lift to pump water efficiently. Screen
portion 175, however, also prevents eggs or fry or egg
shells accidental spilled from incubation tubes 24' from
circulating further in the system and possibly plugging
perforated plates 212. Thus, it is preferable that
screens 198 have a mesh size no large than the screen
portion 175 of head-tube 174.
The foregoing description discusses preferred
and other embodiments in detail. Thus, it is understood
that the invention may be practiced in a number of
fashions. Although numerous characteristics and advent-
ages of the embodiments have been set forth, together with details of structure and function, it is to be understood
that changes may be made, especially in matters of shape,
size and arrangement. Any changes made to the full extent
extended by the general meaning of the terms in which the
appended claims are expressed, are -to be understood to be
within the principle of the invention.
