PROCESS AND DEVICE FOR EVAPORATING LIQUIDS, IN PARTICULAR FORMIC ACID

PROCEDE ET DISPOSITIF POUR L'EVAPORATION DE LIQUIDES, NOTAMMENT DE L'ACIDE FORMIQUE

English Abstract

The invention concerns a process and device for evaporating liquids, in
particular formic acid for combating varroa mites in bee hives. The device
reduces the various environmental influences on evaporation characteristics,
extends the seasonal range and slows down the evaporation rate in the initial
phase. It comprises a storage chamber (1) containing evaporation liquid (10)
and a dispensing chamber (4). Both chambers (1, 4) are separated by a central
partition (2) with a slit-shaped through-aperture (3) at the bottom. Within
the dispensing chamber (4) a constant liquid level (8) is formed and is
independent of the liquid level (7) in the storage chamber (1). Two
evaporating elements (13, 11) are provided in the dispensing chamber (4), the
second (11) of these elements having a rectangular recess (20). The longer
limb of the second evaporating element (11) which projects over a transverse
wall (6) is separated from a third evaporating element (16) by spacer elements
(17) and a constant liquid flow is thereby created within the evaporating
element (11).

French Abstract

L'invention concerne un procédé et un dispositif pour l'évaporation de liquides, notamment de l'acide formique pour lutter contre les mites varroas dans les rûches. Le dispositif permet de réduire les diverses influences de l'environnement sur les caractéristiques d'évaporation, d'accroître la plage d'emploi saisonnière et de ralentir la vitesse d'évaporation dans la phase initiale. Le dispositif comporte une chambre de stockage (1) contenant un liquide à évaporer (10) et une chambre de dosage (4). Ces deux chambres (1, 4) sont séparées par une cloison centrale (2) dotée d'une ouverture traversante en forme de fente (3) à la base. A l'intérieur de la chambre de dosage (4), un niveau de liquide constant (8) est formé et est indépendant du niveau de liquide (7) dans la chambre de stockage (1). Deux éléments d'évaporation (13, 11) sont ménagés dans la chambre de dosage (4), le deuxième (11) de ces éléments présentant un évidement rectangulaire (20). La branche la plus longue du deuxième élément d'évaporation (11) faisant sailliesur une paroi transversale (6) est séparée d'un troisième élément d'évaporation (16) par des éléments d'écartement (17),et un flux constant de liquide est ainsi créé à l'intérieur de l'élément d'évaporation (11).

Claims

13

CLAIMS

1. A process for evaporating liquids, especially formic
acid for combating varroa mites in beehives, wherein
- a constant level of liquid to be evaporated is
produced in a container;
- the main capillary flow of evaporation liquid,
which develops in the evaporation element submerged
in the liquid for evaporation is divided into two
partial capillary flows;
- the first partial capillary flow is directed
vertically upward by the liquid evaporated;
- the second partial capillary flow is first directed
vertically upward, then horizontally and next
vertically downward into an area lower than the
level of the liquid for evaporation, and a suction
effect is produced there;
- the amount of liquid per unit of time of the first
partial capillary flow is kept variable as a
function of ambient conditions such as atmospheric
pressure, atmospheric humidity, air circulation and
temperature,
and
- the amount of liquid of the second partial
capillary flow per unit of time is kept constant.

2. A device for evaporating liquids, especially formic
acid for combating varroa mites in beehives,
comprising an essentially cubical container subdivided
by a vertical middle partition (2) into two container
parts lying in one horizontal plane, where the first
part of the container is designed as a storage chamber
(1) that is closed on all sides to accommodate the
liquid (10) for evaporation, the second part of the
container is designed in steps and is provided with an

14
evaporation element (13), whose lower end face rests
on the bottom surface, and the two parts of the
container are connected by a slot-shaped passage (3)
in the lower part of the vertical middle partition
(2), wherein a third container part is connected to
the second container part in the longitudinal
direction as the evaporation chamber (5) which is
spatially separated from the second container part by
a continuous transverse partition (6), with the bottom
surface of the evaporation chamber (5) being much
lower than the common bottom surface of the storage
chamber (1) and the second part of the container, and
with a longitudinal wall (14) extending from the
vertical middle partition (2) to the right side wall
of the evaporation chamber (5), the left part of
which, forming a dispensing chamber (4) for the liquid
(10) for evaporation, continues to the bottom surface
of the second part of the container, and the length of
the slot-shaped passage (3) in the middle partition
(2) is designed according to the width of the
dispensing chamber (4), and the right part of the
longitudinal wall (14) is provided with a slot-shaped
opening in the lower area, the width of said
slot-shaped opening being greater than the liquid level (9)
in the evaporation chamber (5), and the first
evaporation element (13) is arranged in front of the
longitudinal wall and a second evaporation element
(11) is arranged perpendicular and flush next to the
former, with a U shape having legs of irregular
length, with the left leg, which is supported on the
bottom surface of he dispensing chamber (4) being much
shorter than the right leg which is supported on the
bottom surface of the evaporation chamber (5), and
behind and perpendicular to the longitudinal wall (14)
is arranged a third evaporation element (12), which


has essentially the same shape as the second
evaporation element (11) and its longer leg is also in
contact with the bottom surface of the evaporation
chamber (5), and all the evaporation elements (11, 12,
13) are positioned over the rib sections formed on the
bottom surfaces.

3. A device for evaporating liquids, especially formic
acid, for combating varroa mites in beehives,
comprising an essentially cube-shaped container
subdivided by a vertical middle partition (2) into two
container parts in one horizontal plane, with the
first part of the container being designed as a
storage chamber (1) that is closed on all sides to
accommodate the liquid (10) for evaporation, the
second part of the container being designed steps and
provided with an evaporation element (13) whose lower
end face rests on the bottom surface, and the two
container parts are connected through a slot-shaped
passage (3) in the lower part of the vertical middle
partition (2), wherein the second container part is
limited in the longitudinal direction by a continuous
transverse partition (6), which forms a dispensing
chamber (4) for the liquid (10) for evaporation, and
in which a second evaporation element (11) is arranged
flush next to the first evaporation element (13) and
has a U shape with legs of irregular length, with the
left leg which is supported on the bottom surface of
the dispensing chamber (4) being much shorter than the
right leg, and the bottom part of the transverse
partition (6) being connected to a horizontal spacer
plate (17) which is much lower than the common bottom
surface of the storage chamber (1) and the dispensing
chamber (4), with the longer leg of the evaporation
element (11) resting on the spacer plate (17), which

16
is provided with sieve-like openings for the liquid to
pass through at least in the area of contact of the
longer leg, and with a third evaporation element (16)
being arranged horizontally beneath the spacer plate
(17) and the container, the area of said evaporation
element being larger than the base area of the
container, with a cover being provided beneath the
third evaporation element (16), said cover being
larger in turn than the area of the third evaporation
element (16).

4. A device according to Claim 2, wherein the left part
of the longitudinal wall (14) has a slot-shaped
opening at the bottom, the length of the passage (3)
in the middle partition (2) corresponds to the width
of the container, and the shorter leg of the third
evaporation element (12) is designed to that it does
not dip into the liquid level (8) of the dispensing
chamber (4) when the container is tilted, especially
in transport.

5. A device according to Claim 2, wherein the longer leg
of the third evaporation element (12) is designed with
a right-angled bend, with the bent part of the leg
being arranged directly beneath the longer leg of the
second evaporation element, and with the longer leg of
the second evaporation element (11) being shortened so
that the two evaporation elements (12) do not come in
contact with one another, and the liquid (10) for
evaporation can drip down from the longer leg of the
second evaporation element (11).

6. A device according to Claim 2, wherein the dispensing
chamber (4) and the evaporation chamber (5) are
covered by a protective hood (15), which is detachably

17
connected to the container housing, preferably by
catch and clamp elements, and it has openings in a
number such that a maximum amount of vaporized liquid
can pass through, and its dimensions are such that
direct contact of the bees with the evaporation
elements (11, 12, 13) is prevented.

7. A device according to Claim 2, wherein vertical ribs
are provided in the interspace between the front and
rear longitudinal walls of the dispensing chamber (4)
and evaporation chamber (5) when the dispensing and
evaporation chambers (4, 5) are open at the top,
and/or between the front and rear inner walls of the
protective hood (15) and the evaporation elements (13,
11 and 12), said ribs extending to the top edge (14a)
of the longitudinal walls of the dispensing chamber
and evaporation chambers (4, 5) or to the top edge of
the protective hood (15), said ribs (15a) being
designed as a detachable one-piece spacer element
(14b) or molded on the front and rear insides of the
longitudinal walls and/or the protective hood (15).

8. A device according to Claim 3, wherein the cover is an
acid-resistant plastic film (18), an acid-resistant
dividing plate (23) or an acid-resistant plastic film
(18) with gauze (19) arranged below it, with the area
of the gauze (19) being larger than the area of the
plastic film (18) or the dividing plate (23).

9. A device according to Claims 3 and 8 for use in
back-treatment beehives, wherein the device is arranged on
the lower leg (26) of an empty honeycomb frame (25),
and the third evaporation element (16) under the
spacer plate (17) and the container is sealed with a
plastic film (18) on a longitudinal side approximately

18
flush with the leg (26) of the empty honeycomb frame
(25), said element being bent at an angle on the
opposite longitudinal side and continued vertically
upward, with the plastic film (18) having openings in
a number such that a maximum amount of vaporized
liquid can pass through and the dimensions are such
that direct contact of the bees with the third
evaporation element (16) is prevented.

10. A device according to Claim 2 or 3, wherein the
surface of the second evaporation element (11), except
the end face of the leg, is provided with an
acid-resistant coating or cover that is impermeable for the
liquid (10) for evaporation.

11. A device according to Claim 2 or 3 or 10, wherein the
coating is a plastic or an enamel.

12. A device according to Claim 2 or 3, wherein the cross
section through the second evaporation element (11) is
preferably adjustable or variable in the horizontal
middle part.

13. A device according to Claim 2 or 3 and 12, wherein the
second evaporation element (11) consists of two
individual L-shaped elements whose short legs are
arranged so that they overlap in an area, and at least
one individual element is horizontally displaceable,
and the short leg of the one individual element runs
at a right angle and that of the other individual
element is at an inclination.

14. A device according to Claim 2 or 3, wherein the first
and second evaporation elements (13, 11) are designed
in one piece.

19

15. A device according to Claim 2 or 3, 5 as well as 10
through 14, wherein the cross-sectional area of the
evaporation elements (11, 12, 13) is regular,
especially triangular, rectangular, polygonal,
circular, annular, sector-shaped, arc-shaped,
ellipsoidal, or it may be irregular.

16. A device according to Claim 2 or 3, 5 as well as 10
through 14, wherein the absorbent material of the
evaporation elements (11, 12, 13, 16) is made of
organic or inorganic materials or mixtures thereof.

17. A device according to Claim 2 or 3, 5 as well as 10
through 14 and 16, wherein the absorbent material of
the evaporation elements (11, 12, 113, 16) is paper,
cardboard, ceramic, foam and a woven or nonwoven
textile material such as a felt, a nonwoven or spun
yarn.

18. A device according to Claim 2 or 3, wherein the
container is made of acid-resistant and weldable
plastics, preferably polypropylene.

19. A device according to Claim 2 or 3, wherein the
container is designed so that it can be tilted by
providing a height adjusting device (21) on the left
side wall of the storage chamber (1).

20. A device according to Claim 2 or 3, wherein the width
of the container is not greater than the width of a
honeycomb frame.

21. A device according to Claim 2 or 3, wherein the
container is an injection molded part which has a


scale for measuring the quantity of liquid (10) to be
evaporated in the storage chamber (1), preferably on
the cover of the storage chamber (10, and the cover is
connected to the housing of the storage chamber (1) by
welding with an airtight seal.

22. A device according to Claim 2 or 3, 5 as well as 10
through 14, wherein the evaporation elements (11, 12,
13) are arranged at any angle, even variably, to the
vertical axis or the horizontal axis of the container.

Description

CA 022470~1 1998-08-21


PROCESS AWD DEVICE FOR EVAPORATING LIQUIDS,
IN PARTICULAR FORMIC ACID

The invention concerns a method and a device for
evaporating liquids, in particular formic acid for
combating varroa mites in beehives.

The term "evaporation" is used in the following description
in the sense of a slow transition from a liquid to gaseous
state at temperatures far below the boiling point of the
liquid evaporated.

German Democratic Republic Patent No. DD 292 141 B5 has
already disclosed a device for evaporating liquids, in
particular formic acid, consisting of an essentially cube-
shaped container subdivided by a vertical middle partition
into two container parts. The first part of the container
is designed as a storage chamber that is closed on all
sides to accommodate the liquid for evaporation. The second
part of the container is designed with stepped shoulders to
accommodate a plate-shaped evaporation element which is
positioned in a vertical position above a slot in a cover,
and the bottom end face of which is in contact with the
bottom surface. A slot-shaped passage is provided in the
lower part of the vertical middle partition, establishing a
connection between the two parts of the container in
proximity to the common bottom surface.
Operation of this known device consists of the fact that
the liquid for evaporation flows out of the storage chamber
through the passage and into the second part of the
container, where it rises only until the liquid seals the
passage. The reason for this is that a vacuum develops as
the liquid flows out of the storage chamber, preventing any
further rise of liquid for evaporation in the second part
of the container. Then when liquid for evaporation is

CA 022470~1 1998-08-21
,. .

removed through the evaporation element, the liquid level
in the second part of the container drops slightly, and air
in the form of small air bubbles is drawn into the storage
chamber and the vacuum is compensated, so that more liquid
can flow into the second part of the container. The liquid
level then rises until the passage is sealed again, thereby
interrupting the supply of air. This yields an
approximately constant liquid level in the second part of
the container, thereby guaranteeing a uniform delivery
stream in the evaporation element independently of the
different filling levels in the storage cham~er.

Evaporation of liquid is known to depend on many
parameters. Important influencing factors include the size,
shape and porosity of the surface of the evaporation
element, the atmospheric pressure, atmospheric humidity and
air circulation as well as the temperature.
The disadvantage of the known device is that the
evaporation rate (i.e., the amount evaporated per unit of
time) varies greatly due to the dependence on some of the
ambient conditions mentioned above, namely atmospheric
pressure, atmospheric humidity, air circulation and
temperature. In addition, the treatment combating varroa
mites must be performed several times a year in different
seasons. In Germany, this is not done until the summer,
approximately in August after the last honey harvest and in
the autu-m--n~ approximately in Septe_ber/October. It follows
from this that different external ambient conditions will
prevail at the time of treatment. However, an important
factor in effective control is achieving an adequate
concentration of formic acid in the vaporized air in the
beehive. In Germany, there are standards in this regard for
the m~ximllm and m; n;mllm evaporation rates based on the
ambient temperature, which is approximately 10 mL per day
at temperatures of about 15~C to 20~C in the fall, whereas

CA 022470~1 1998-08-21
,.

in the summer when temperatures are approximately 25~C to
30~C, it is about 25 mL per day. Ambient conditions inside
a beehive are also by no means constant.
Bees always try to maintain a constant temperature, for
example, +35~C in the breeding nest. At higher outside
temperatures or in direct sunlight, air in the beehive is
cooled by the fact that a certain number of bees produce a
directed stream of air by the movement of their wings, so-
called "fanning" which is directed outside through an
opening while more fresh air flows into the beehive. Thus,
there is a high rate of air turnover, which reduces the
concentration of formic acid in the beehive.
To compensate for the disadvantages of the known device,
various large evaporation elements have been used in the
past for different ambient conditions, and checks during
treatment are recommen~ed for optimizing the amount
evaporated. These measures are not only cost-intensive but
are also very expensive.
Another disadvantage of the known device is also that the
amount of liquid evaporated rises very rapidly in the
initial phase of the treatment. As a result, there is an
increase in stress for the bees and their aggressiveness,
which can endanger the life of the queen.

The object of the present invention is to create a method
and an improved device according to the definition of the
species of Patent Claims 1, 2 and 3, with which the effects
of the different ambient conditions on the evaporation
characteristics are reduced, the seasonal scope is
increased without using different sizes of evaporation
elements, and a very slow increase in evaporation in the
initial phase is achieved.

This ob~ect is achieved through the features given in the
characterizing parts of Claims 1, 2 and 3. Expedient

CA 022470~1 1998-08-21


embodiments of the device are disclosed in Claims 4 through
22.

The advantages achieved with this invention are explained
as follows:

With the known evaporators where only one evaporation
element is immersed in the liquid to be evaporated in a
container, it has been found experimentally that the
delivery rate (i.e., the amount of liquid per unit of time)
is much different when the container is completely full
than when the container is almost empty. Due to this
dependence on the liquid level in the container, there is
another influencing factor on the evaporation
characteristics in addition to the ambient conditions. This
influencing factor is eliminated by the design of the
storage chamber in combination with the slot-shaped passage
so that a constant level of liquid to be evaporated is
produced in the dispensing chamber, wherein the evaporation
element is always immersed to the same depth. Due to the
use of two evaporation elements which are supplied with
liquid for evaporation from the dispensing chamber, the
main capillary flow is divided into two partial capillary
flows. The first partial capillary flow rises vertically
upward over the first evaporation element and evaporates
according to the given ambient conditions. For example, at
higher temperatures or with more air circulation, more
liquid will evaporate than at a lower temperature or with
lower air circulation. Since the first evaporation element
is in direct contact with the liquid level in the
dispensing chamber, it always draws up more liquid for
evaporation in accordance with the amount of liquid already
evaporated. The amount of liquid per unit of time of the
first partial capillary flow thus changes as a function of
ambient conditions. Due to the U-shaped design of the

CA 022470~1 1998-08-21


second evaporation element, the second partial capillary
flow is diverted due to the effect of capillary force and
gravity into a lower evaporation chamber where the liquid
drips down from the longer leg onto a third evaporation
element or is dispensed to this element. This forms a wet
spot of liquid for evaporation. However, the third
evaporation element is arranged at a distance from the
second evaporation such that the possibility of mutual
contact between the two elements is ruled out, so that no
more liquid can be resupplied by suction with the
evaporation of the liquid spot, in contrast with the first
evaporation. The second partial capillary flow is thus
constant and is independent of ambient conditions, in
particular when the second evaporation element is provided
with an additional coating or cover. The size of the liquid
spot on the third evaporation element is then determined
exclusively by the stream of liquid dripping off the
element. If the evaporation of the liquid spot begins
according to the given ambient conditions, its effective
evaporation area is reduced until more liquid drips down
again. With an appropriate design of the second evaporation
element, it is possible for the liquid spot to evaporate
completely before more liquid drips down again.
Since the liquid spot can develop on the third evaporation
element only with a delay and optionally at certain
intervals, only a gradual increase in evaporation is
achieved on the whole in the initial phase.
The effects of the first evaporation element and the
effects of the second and third evaporation elements are
mutually complementary, so that the effects of the ambient
conditions are reduced, and the seasonal scope is increased
without using evaporation elements of different sizes.

This invention will be explained in greater detail below on
the basis of several embodiments. The respective figures

CA 022470~1 1998-08-21

6 '
show the following:
~igure 1 - the front view of the evaporation device
according to a first embodiment in a sectional
diagram;
~igure 2 - section A-A according to Figure l;
~igure 3 - the front view of the evaporation device
according to a second embodiment in a sectional
diagram;
~igure 4 - section B-B according to Figure 3;
~igure 5 - the front view of the evaporation device
according to a third embodiment in a sectional
diagram;
~igure 6 - a top view of the evaporation device according
to Figure 5;
~igure 7 - the front view according to Figure 5 in a
tilted position;
~igure 8 - the front view of the evaporation device
according to a fourth embodiment in a sectional
diagram;
~igure 9 - a front view of the evaporation device
according to Figure 8;
~igure 10 - the front view o~ the evaporation device
according to a fifth embodiment in a partial
sectional diagram;

CA 022470~1 1998-08-21


Figure 11 - section C-C according to Figure 10;
~igure 12 - the front view of the evaporation device
according to a sixth embodiment in a sectional
diagram;
~igure 13 - section D-D according to Figure 12.

Figures 1 through 4 and 12 through 13 show a first basic
variant, and Figures 5 through 11 show a second basic
variant of the device according to the present invention
for evaporating liquid. As shown in Figures 1 through 13,
the device consists of an essentially cube-shaped
container, subdivided by a vertical middle partition 2 into
two container parts having a common bottom surface. The
first container part is designed so that it is closed on
all sides and serves as a storage chamber 1 for the liquid
10 for evaporation. The second container part is set off
with steps from the first container part, and it serves as
a dispensing chamber 4 for the liquid 10 for evaporation.
Storage chamber 1 and dispensing chamber 4 are connected by
a slot-shaped passage 3, so that a constant liquid level 8
is produced in dispensing chamber 4 and is independent of
liquid level 7 in the storage chamber 1. Details regarding
this liquid level 8 have already been explained in the
introductory discussion regarding German Democratic
Republic Patent No. 292,141 B5.
In the first basic variant presented in Figures 1 through 4
and 12 through 13, a third container part which serves as
the evaporation chamber is connected in the longitudinal
direction to the second container part. This evaporation
chamber 5 is separated spatially from dispensing chamber 4
by a continuous transverse partition 6. The bottom surface
of the evaporation chamber 5 is much deeper than the bottom
surface of the storage chamber 1 and of dispensing chamber

CA 022470~1 1998-08-21


4. A longitudinal wall 14 which is arranged in evaporation
chamber 5 extends from middle partition 2 to the right side
wall of evaporation chamber 5. According to one embodiment,
the left part of this longitll~in~l wall 14 is continuous
all the way to the bottom surface of the dispensing chamber
4, with the length of passage 3 being limited by the
longitudinal wall 14. According to another embodiment, the
left part of longitudinal wall 14, however, has a slot-
shaped opening at the bottom, and passage 3 extends over
the entire width of the container. A first evaporation
element 14 is in front of longitll~l n~l wall 14, and a
second evaporation element 11 is arranged perpendicular to
and flush with it. This second evaporation element 11 is
provided with a rectangular cutout 20, thus resulting in a
U shape with legs of different lengths. The left leg
supported on the bottom surface of the dispensing chamber g
is much shorter than the right leg. This right leg need not
lie on the bottom surface of the evaporation chamber 5; it
may also be shorter, especially when dripping of liquid 10
for evaporation is to be achieved. In another embodiment of
the invention, a third evaporation element 12 which is
arranged perpendicularly behind the longitudinal wall 14
has essentially the same U shape as the second evaporation
element 11 and its longer leg rests on the bottom surface
of the evaporation chamber 5. In adaptation to the
embodiment whereby the left part of the longitudinal wall
14 has a slot-shaped opening at the bottom, the shorter leg
of the third evaporation element 12 must be of a size such
that it is not immersed in liquid level 8 of dispensing
chamber 4 when the container is tilted, e.g., in transport.
According to an expedient embodiment of this first basic
variant, the longer leg of the third evaporation element 12
is designed as a right angle. The bent leg part is in
contact with the bottom surface of the evaporation chamber
5 and is continued to beneath the longer leg of the second

CA 022470~1 1998-08-21
.
9.
evaporation element 11. The longer leg of the second
evaporation element must be shortened so that the two
evaporation elements do not come in contact with one
another.
In the first embodiment illustrated in Figures 1 and 2, the
dispensing chamber 4 and the evaporation chamber 5 are
covered at the top by a protective hood 15. This protective
hood is detachable connected to the container housing,
which is expediently accomplished with catch and clamp[
elements. Protective hood 15 has several openings, the
number of which is such that a m~ximllm amount of vaporized
liquid can pass through. The ~;m~n~ions of these openings
are designed so as to prevent the bees from coming in
direct contact with evaporation elements 11, 12, 13.
In the second embodiment (Figures 3 and 4), the protective
hood 15 is open at the top but does not otherwise have any
additional orifices. To permit contact protection and also
to achieve better positioning of evaporation elements 11,
12 13, there are vertical ribs 15a arranged at a distance
of approximately 3.5 mm. These ribs 15a are arranged in the
interspace between the front and rear longitudinal walls of
the dispensing chamber 4 and the evaporation chamber 5 as
well as the front and rear walls of protective hood 15 and
the evaporation elements 13, 11 and 12. These ribs 15a may
either be provided only in the area of protective hood 15
or they may run vertically and continuously from the bottom
surface of dispensing chamber 4 and evaporation chamber 5
up to the top edge of protective hood 15. Ribs 15a may
expediently be designed as a one-piece spacer element 14b
which is inserted into the abovementioned interspace.

However, it is also possible for the ribs to be designed as
part of the front and rear walls of the dispensing chamber
4 and evaporation chamber 5 and the protective hood 15, or
they may be provided only on the protective hood 15.

CA 022470~1 1998-08-21

10'
The sixth embodiment according to Figures 12 and 13 differs
from the first embodiment (Figures 1 and 2) in that the
second evaporation element 11 consists of two individual L-
shaped elements whose short legs overlap in a certain area
and are horizontally displaceable. Due to the fact that one
leg runs at a right angle and the other leg is at an
~rclinat~or, the crosC section of the second evaporat~on
element 11 is adjustable. The external ~;m~ncions of the
device are thus adapted to the requirements of conventional
beehives by being mounted in a honeycomb frame 25, so they
can be positioned in the beehive instead of a honeycomb. In
any case, the width of the device is no greater than the
width of an empty honeycomb frame 25. On the one hand, the
breeding nest temperature, which is kept constant by the
bees, contributes toward evaporation, but on the other
hand, direct contact with the breeding nest can cause brood
damage, so the device is arranged primarily in the first
brood-free honeycomb gases.
The second basic variant illustrated in Figures 5 through
11 differs from the first basic variant in that no
spatially limited evaporation chamber 5 is provided, the
bottom part of the transverse partition 6 is connected to a
horizontal spacer plate 17, and the third evaporation
element 16 is arranged horizontally below spacer plate 17
and the container. The spacer plate 17 is likewise also
much lower than the common bottom surface of the storage
chamber 1 and dispensing chamber 4. Spacer plate 17 is
provided with mesh-like openings for the liquid to pass
through, at least in the area of the longer leg. The area
of the third evaporation element 16 is larger than the base
area of the device. In addition, a cover is provided under
the third evaporation element 16, and this is in turn
greater than the area of the third evaporation element 16.
In the third embodiment according to Figures 5, 6 and 7,
this cover is made of an acid-resistant plastic film 18

CA 022470~1 1998-08-21

11'
with gauze 19 arranged beneath it.
In the fourth e-m-bodiment according to Figures 8 and 9,
however, the cover consists of an acid-resistant dividing
plate 23 provided with feet 24.

The cover of the fifth e_bodiment according to Figures 10
and 11 consists only of the dividing film 18.

Figure 7 shows that a height adjusting device 21 may be
provided on the left side wall of the storage chamber 1,
m~king it possible to tilt the device, so that liquid level
8 in dispensing chamber 4 can be reduced for the
evaporation element 13.
The embodiments shown in Figures 5 through 9 are preferably
used when in an advanced season the regulatory effect of
the shrunken breeding nest has become m;n;m~l, and there
should not be any intervention into the honeycomb
arrangement, and yet on the other hand it would be
desirable to postpone the last treatment of the current
year because of possible reinfection from the environment.
The device would then be set up in a space that is free of
bees, preferably above the beehive.

However, the fifth embodiment is intended for use in so-
called back-treatment hives between the window and the last
honeycomb. Therefore, the device is mounted on the lower
leg (26) of an empty honeycomb frame 25, with the third
evaporation element 16 and the plastic film 18 ending
approximately flush with leg 26 of the empty honeycomb
frame 25 on a longitudinal side and being angled on the
opposite longitudinal side and then leading vertically
upward. As in the first embodiment, the plastic film 18
likewise has openings.

It has proven to be very advantageous for all embodiments

CA 022470~1 1998-08-21
.
12
if the surface of the second evaporation element 11 is
provided with an acid-resistant coating or cover, which may
be a plastic or an enamel which is impermeable for the
liquid 10 to be evaporated, except on the end faces of the
leg. This design prevents evaporation of the capillary flow
on its path to the longer leg of the second evaporation
element 11, which then performs only a simple transport
function for the liquid 10 to be evaporated.

Representative Drawing