U.S. patent application number 10/181618 was filed with the patent office on 2003-01-02 for additive nebulising device.
Invention is credited to Berner, Michael, Engler, Wolfgang, Sonn, Michael, Zindl, Manfred.
Application Number | 20030000773 10/181618 |
Document ID | / |
Family ID | 7628205 |
Filed Date | 2003-01-02 |
United States Patent
Application |
20030000773 |
Kind Code |
A1 |
Engler, Wolfgang ; et
al. |
January 2, 2003 |
Additive nebulising device
Abstract
An additive atomizing device and further means and a method for
the atomization of a liquid additive in a gaseous pressure medium,
more particularly compressed air, flowing through a pressure medium
flow duct (10). The additive is conveyed from one inlet (26) of an
additive passage duct (24) for supplying the additive from an
additive supply means (27 and 28) to an outlet (25) opening into
the pressure medium flow duct (10). A detecting means (17 and 18)
detects at least one physical characteristic in the pressure medium
flow duct (10) and signalizes same by way of a signalizing means
(19 and 20) to a control means (21). The control means (21)
controls a pressure producing device (43 and 47) in a manner
dependent on the at least one physical characteristic found by the
detecting means (17 and 18) by way of a control connection (23. The
pressure producing device (43 and 47) causes pressure pulses to act
on the additive in the at least one additive passage duct (24) so
that the drops of additive are expelled from the outlet (25).
Inventors: |
Engler, Wolfgang;
(Plochingen, DE) ; Zindl, Manfred; (Reutlingen,
DE) ; Sonn, Michael; (Kirchheim/Teck, DE) ;
Berner, Michael; (Kirchheim/Teck, DE) |
Correspondence
Address: |
HOFFMANN & BARON, LLP
6900 JERICHO TURNPIKE
SYOSSET
NY
11791
US
|
Family ID: |
7628205 |
Appl. No.: |
10/181618 |
Filed: |
July 19, 2002 |
PCT Filed: |
January 13, 2001 |
PCT NO: |
PCT/EP01/00378 |
Current U.S.
Class: |
184/6.26 |
Current CPC
Class: |
B05B 12/1436 20130101;
B05B 7/2494 20130101; B05B 12/085 20130101; B05B 12/1427 20130101;
F16N 7/34 20130101; B05B 7/2497 20130101; B05B 17/04 20130101; B05B
7/0075 20130101 |
Class at
Publication: |
184/6.26 |
International
Class: |
F01M 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 21, 2000 |
DE |
10002414.9 |
Claims
1. An additive atomizing device for the atomization of a liquid
additive, and more particularly of a lubricant, in a gaseous
pressure medium, more particularly compressed air, comprising at
least one additive passage duct (24), which has an inlet (26) for
the supply of the additive from an additive supply means (27 and
28) and whose outlet (25) opens into a pressure medium flow duct
(10), through which the pressure medium flows, characterized in
that the pressure medium passage duct (10) is provided with a
detecting means (17 and 18) for determining at least one physical
characteristic, which can be passed by the detecting means (17 and
18) by way of a signalizing means (19 and 20) to a control means
(21) and that a pressure producing device (43 and 47) is provided
in the at least one additive passage duct (24), it being possible
for a pressure pulse to be exerted on the additive by the pressure
producing device so that a drop of additive is expelled at the
outlet (25), such pressure producing device being arranged to be
controlled by the control means (21) in a manner dependent on the
at least one physical characteristic as found by the detecting
means (17 and 18).
2. The additive atomizing device as set forth in claim 1,
characterized in that the pressure producing device (43 and 47)
comprises at least one piezoelectric and/or magnetostrictive and/or
memory metallic (43) and/or a heating element (47) evaporating the
additive or a separate working liquid, for the production of the
pressure pulse.
3. The additive atomizing device as set forth in claim 1 or claim
2, characterized in that the detecting means (17 and 18)
determines, as at least one physical characteristic, the
instantaneous flow rate of the pressure medium through the pressure
medium flow duct (10).
4. The additive atomizing device as set forth in claim 1, claim 2
or claim 3, characterized in that the detecting means (17 and 18)
as at least one physical characteristic determines the
concentration of the additive in the pressure medium.
5. The additive atomizing device as set forth in any one of the
claims 1 through 4, characterized by a heating device and/or
cooling device (36), which conditions the additive, preferably at
least in one section of the additive atomizing device (24) for
viscosity conditioning.
6. The additive atomizing device as set forth in any one of the
claims 1 through 4, characterized in that the additive supply means
(27 and 28) is designed as a component of the additive atomizing
device and possesses at least one releasable and cartridge-like
container (27 and 28) provided to receive an additive supply.
7. The additive atomizing device as set forth in any one of the
claims 1 through 6, characterized in that the additive passage duct
(24) is formed in an injection head (22), which has an connection
part for at least one detachable cartridge-like container (51),
which is connected with the at least one inlet (26) of the additive
passage duct (24).
8. The additive atomizing device as set forth in any one of the
claims 1 through 7, characterized in that it comprises a connection
duct (33) leading to the pressure medium flow duct (10) by way of
which the additive supply means (27 and 28) may be so acted upon by
the pressure medium that the additive is subjected to a pressure
from the additive supply means (27 and 28) directed toward the
additive passage duct (24).
9. The additive atomizing device as set forth in any one of the
claims 1 through 8, characterized in that the additive passage duct
(24) is in the form of a capillary in at least one a part thereof
so that after expulsion of a drop (50) of additive from the outlet
(25) additive is propelled by capillary action from the additive
supply means (27 and 28) into the additive passage duct (24).
10. The additive atomizing device as set forth in any one of the
claims 1 through 9, characterized in that at least one blade able
to be operated by piezoelectric and/or magnetostrictive and/or
memory metallic action is provided as a pressure producing device
(43 and 47) in the additive passage duct (24).
11. The additive atomizing device as set forth in claim 10,
characterized in that the blade (43) able to be operated by
piezoelectric and/or magnetostrictive and/or memory metallic action
is so arranged that the blade closes the outlet (25) on the
application of an electrical neutral voltage and/or a magnetic
neutral field and/or a neutral temperature.
12. The additive atomizing device as set forth in claim 10, 10,
characterized in that the at least one blade (43) is biased into a
position closing the outlet (25).
13. The additive atomizing device as set forth in any one of the
claims 1 through 12, characterized in that in the pressure medium
flow duct (10) a flow directing means (32) is provided, by which
the drops of additive expelled at the at least one outlet (25) are
directed out of their path of expulsion.
14. The additive atomizing device as set forth in any one of the
claims 1 through 13, characterized in that the additive atomizing
device comprises the control means (21).
15. A fluid technology means, for example in the form of a valve or
a drive, which is provided with at least one additive atomizing
device as set forth in any one of the claims 1 through 14, the
pressure medium flow duct (10) being formed directly in the fluid
technology means.
16. The fluid technology as set forth in any one of the claims 1
through 14, characterized in that the at least one additive
atomizing device is in the form of a component of the fluid
technology means.
17. A material preparing unit, as for example an oiler, for a
gaseous pressure medium, and more particularly for compressed air,
characterized in that the material preparing unit comprises at
least one additive atomizing device as set forth in any one of the
claims 1 through 14.
18. An additive supply means (27 and 28) for an forth in claim 15
or in claim 16, or for a material preparing unit as set forth in
claim 17, characterized in that the additive supply means (27 and
28) comprises at least one injection head (22), in which the
additive passage duct (24) is formed and which possesses a
connection part for at least one replaceable cartridge-like
container (51), adapted to recive a supply of additive, which
container is connected with the at least one inlet (26) of the
additive passage duct (24) and that the at least one injection head
(22) possesses an injection head connection means (56), by way of
which the injection head (22) may be joined with the pressure
medium passage duct (10).
19. A method for the atomization of a liquid additive, more
particularly a lubricant, in a gaseous pressure medium, more
especially compressed air, which pressure medium flows through a
flow duct (10), the additive being conveyed from an inlet (16) of
at least one additive passage duct (24) for supply of the additive
from an additive supply means (27 and 28) to an outlet (25) opening
into the pressure medium flow duct (10), characterized in that a
detecting means (17 and 18) detects at least one physical
characteristic in the pressure medium flow duct (10), that the
detecting means (17 and 18) passes on the at least one physical
characteristic by way of a signalizing means (19 and 20) to a
control means (21), that in the at least one additive passage duct
(24) a pressure producing device (43 and 47) exerts pressure pulses
on the additive, and that the control means (21) controls the
pressure producing device (43 and 47) in a manner dependent on the
at least one physical characteristic as determined by the detecting
means (17 and 18).
Description
[0001] The invention relates to an additive atomizing device for
the atomization of a liquid additive, and more particularly of a
lubricant, in a gaseous pressure medium, more particularly
compressed air, comprising at least one injection head, which has
at least one additive passage duct, which has an inlet for the
supply of the additive from an additive supply means and whose
outlet opens into a pressure medium flow duct, through which the
pressure medium flows.
[0002] The invention furthermore relates to a fluid technology
means, for instance in the form of a valve or a drive, a material
preparing means, as for instance an oiler, a cartridge-like
additive supply means for an additive atomizing device and
furthermore a method for the, atomization of a liquid additive, and
more especially a lubricant in a gaseous pressure medium.
[0003] In a pneumatic system, which is operated by compressed air,
the pneumatic elements of the system are supplied by one or more
so-called compressed air oilers with lubricant. These lubricants
must serve to provide for a low wear rate of the moving parts, to
keep frictional forces in the elements at a low level and to
protect the equipment against corrosion. Compressed air oilers
normally use the venturi principle. In this case the compressed air
is caused to pass through a constriction in the compressed air
duct. At such constriction there is an outlet from a thin tube,
which dips into a container for oil or some other additive. Owing
to the pressure difference between the pressure upstream from the
constriction and the pressure at the smallest cross section of the
constriction the oil is drawn from the container mixed with air.
Such a compressed air oiler is described in the book "Pneumatische
Steuerungen" by Werner Depert and Kurt Stoll, 10th edition 1994,
ISDN 3-8023-1549-9, pages 43 and 44.
[0004] A problem in connection with such compressed air oilers is
that the compressed air oiler only starts to operate when a
sufficiently large flow is present. In the case of an excessively
small removal of air the flow velocity at the nozzle is nolonger
sufficient to produce a sufficient vacuum and accordingly to draw
oil from the container. Furthermore, the designer is bound to the
oil pumping characteristic, that is to say to the oil pumping rate
as dependent on the air flow rate, of the device, which cannot be
changed. Oil metering adaptable to the different pneumatic elements
is therefore hardly possible. A further disadvantage of such
compressed air oilers is the great temperature dependence of the
oiling action owing to the changes in viscosity in the oil in a
manner dependent on the respective temperature.
[0005] Accordingly one object of the invention is to distribute an
additive and more especially a lubricant, in a gaseous pressure
medium, more particularly compressed air with an optimum
possibility of adjustment.
[0006] This object is achieved in accordance with the invention
because the pressure medium passage duct is provided with a
detecting means for determining at least one physical
characteristic, which can be passed by the detecting means by way
of a signalizing means to a control means and a pressure producing
device is provided in the at least one additive passage duct, it
being possible for a pressure pulse to be exerted on the additive
by the pressure producing device so that a drop of additive is
expelled at the outlet, such pressure producing device being
arranged to be controlled by way of a control connection by the
control means in a manner dependent on the at least one physical
characteristic as found by the detecting means.
[0007] The object is furthermore to be achieved by a fluid
technology means in accordance with the technical teaching of claim
15, by a material preparing unit in accordance with the technical
teaching of claim 17, by a cartridge-like additive supply means in
accordance with the technical teaching of claim 18 and by a method
in accordance with the technical teaching of 19.
[0008] Therefore in accordance with the invention an additive is
not atomized by an entraining effect of compressed air but by
injection using a pressure producing device. This pressure
producing device is able to be controlled by a control means, which
controls the pressure producing device in a fashion dependent on
the physical characteristic, as for instance the instantaneous flow
rate of the pressure medium in the pressure medium flow duct or on
the concentration of the additive in the pressure medium. In this
case only a small amount of technical complexity is required to
obtain a constant additive concentration in the pressure medium, as
is required and in a reproducible manner, or--for a short time--a
greater or weaker concentration. Furthermore, by parametric
synthesis of the control means or by some other, externally
provided preset of control means it is possible for the shoot rate
and/or the additive drop size to be set extremely accurately. When
there is no flow of the pressure medium in the pressure medium flow
duct during in interval in operation, accordingly no additive is
injected into the pressure medium.
[0009] Devices designed and operating in accordance with the
invention have only a small number of mechanical components liable
to failure. Owing to the "active" injection of the additive using
pressure atomization devices immediately and exactly metered out
additive is supplied to the pressure medium and the additive is not
just supplied, as in the prior art, by "entrainment". The devices
in accordance with the invention therefore respond rapidly and mean
that there are no flow losses of the pressure medium or only very
small ones.
[0010] Further convenient developments of the invention are defined
in the dependent claims.
[0011] For the pressure producing device it is possible for
instance to employ piezoelectric, magnetostrictive, or
memory-metallic element. Same may for example be in the form of a
diaphragm or blade and subject the additive to a pressure pulse in
the additive passage duct. Combinations of the above mentioned
materials are also possible.
[0012] In a particularly preferred form of the invention the
pressure producing device comprises a blade selected from the above
mentioned materials. Such a blade is then for example designed in
the form of a flexural transducer, which pumps the additive toward
the outlet. The flexural transducer may be so designed that it
closes the outlet in the neutral position. The flexural transducer
is biassed accordingly or is moved into the a position closing the
outlet by an electrical neutral voltage, a magnetic field or a
constant temperature.
[0013] The pressure producing device may however also operate in
accordance with an evaporation principle, in the case of which
either a vapor bubble is formed in the additive or in a working
liquid, as for instance water, by a heating element subject to a
pulse. The vapor bubble then thrusts the additive toward the
outlet. To the extent that a working liquid is utilized, same is
separated by a diaphragm from the additive in the additive passage
duct. It is then not necessary to take into the chemical and
physical quality of the additive as regards the formation of vapor
bubbles.
[0014] An other preferred feature is such that the additive is so
conditioned by heating--or cooling--that it possesses an optimum
consistency in the additive passage ducts or in the case of
injection into the pressure medium as well. It is convenient for
the additive then to be heated at the respective additive passage
duct so that the pressure producing device develops an optimum
action. For sensing and then controlling the temperature it is
possible in addition for a sensor to be arranged in the respective
additive passage duct. It is however possible also for the entire
additive atomizing device as a whole to be heated or cooled. The
additive atomizing device is then preferably insulated from the
surroundings by an insulating casing.
[0015] The additive is preferably supplied from cartridge-like,
replaceable containers. In this case several such containers may be
connected with a common supply line. It is however also possible
for such a container to have an injection head, which together with
the container is mounted on the respective additive atomizing
device. Thus it is possible for the injection head as well, which
is subject to a certain amount of corrosion or wear by the additive
or may be at least partly blocked by the additive, to be replaced
together with the container in an extremely simple fashion.
[0016] In order to move the additive in the additive passage duct
the additive supply device is, in accordance with preferred form of
the invention, supplied with the pressure medium from the pressure
medium flow duct at the inlet. It is however also possible to feed
the additive into the additive passage duct simply by the pressure
of the surroundings, acting on the additive supply means, from the
supply means. Moreover, the additive passage duct can also be so
designed, at least in part thereof, as a capillary so that owing to
the capillary action additive is drawn from the additive supply
means into the additive passage duct.
[0017] Since the additive atomizing device may be made extremely
compact, it is also possible to incorporate it directly in a fluid
technology means, for example in the form of a valve or a drive. It
may however also be incorporated in a material preparing unit, as
for instance in an oiler for a pneumatic system.
[0018] More particularly in cases in which the control means only
comprises a few components, as for instance a small microcontroller
or a few analog electrical regulator components, the control means
may directly integrated in the additive atomizing device or in a
component group comprising the additive atomizing device. It is for
instance possible as well, however, for the control means to be
formed centrally, for instance in the form of a microprocessor
control system, which controls several additive atomizing devices.
It is also possible for a small microprocessor, controlling same,
to be provided for each additive atomizing device, such
microprocessor being under the control of a higher order control,
for instance by way of a field bus. Using this high order control
it is then for example possible to accurately set, for example, the
additive concentration in the pressure medium and to check any
additive concentration already present, for example using a
display.
[0019] Working examples of the invention will be now described with
reference to the accompanying drawings.
[0020] FIG. 1 diagrammatically shows a first working example of an
additive atomizing device in accordance with the invention.
[0021] FIG. 2A shows a additive passage duct in the form of a
chamber with a blade as an actuator.
[0022] FIG. 2A shows a passage duct as in FIG. 2A, in the case of
which the blade closes outlet openings of the additive passage
duct.
[0023] FIG. 3 shows an additive passage duct in the form of a
capillary with a heating element.
[0024] FIG. 4 diagrammatically shows a working example of an
injection head with a cartridge connected with it.
[0025] FIG. 5 shows a working example similar to that of FIG. 1
having an additive atomizing device in accordance with the
invention but however with separate additive supply means, each
provided with an injection head.
[0026] FIG. 1 shows an additive atomizing device having a pressure
medium flow duct 10, which is delimited by a wall 11. The pressure
medium flow duct 10 carries gaseous pressure medium, more
particularly compressed air, flowing in the direction of the arrow
13. The pressure medium flow duct is for example a component of a
servicing device for pneumatic systems, as for instance an oiler,
or is part of a fluid technology means, as for example in the form
of a valve or a drive. The pressure medium then flows in the
direction 13 of the arrow to one or more such valves or drives.
[0027] The pressure medium flow duct 10 possesses a constriction 14
which is formed by a baffle-like bay 15, which is located in the
wall 11. Owing to the constriction 14 there is a pressure gradient
in the flow duct 10, which is measured by a detecting means in the
form of pressure sensors 17 and 18. The sensors 17 and 18 are
respectively joined by a connection 19 and 20 with a control means
21. The connections 19 and, respectively, 20 are signalizing means
and may for example be in the form of line, radio link or infrared
connections. The control means 21 is for example a microprocessor
or an analog regulating means. On the basis of the pressure
difference, which is measured between the sensors 17 and 18, the
control means 21 can find out how great the instantaneous flow rate
of the pressure medium through the pressure medium flow duct 10 is.
In lieu of the pressure sensors 17 and 18 an electric generator,
driven by the pressure medium, or a heating filament element could
be arranged in the pressure medium flow duct 10 for measuring the
flow rate.
[0028] The control means 21 is furthermore joined with an injection
head 22 by way of a connection 23. Like the connections 19 and 20
the connection 23 can also be a line, a radio link or an infrared
connection. In the present case the injection head 22 possesses
three parallel additive passage ducts 24. It is however also
possible for the injection head 22 to possess only one additive
passage duct or a plurality of additive passage ducts. Toward the
flow duct 10 the additive passage ducts 24 respectively have an
outlet 25. At the inlet end the additive passage ducts 24 are
joined with a supply line 26, which leads to additive supply
containers 27, 28, 19 and 30. The supply containers are preferably
designed in the form of replaceable cartridges and may be plugged
or screwed on the supply line 26 using flanges, not illustrated in
FIG. 1. Additive, as for example oil, passes from the supply
containers 27 through 30 by way of the supply line 26 into the
additive passage ducts 24. In lieu of the supply containers 27
through 30 a central additive supply means could also be provided,
which in addition to the additive atomizing devices illustrated in
FIG. 1 would supply other additive atomizing devices as well.
[0029] In the additive passage ducts 24 there are respective
pressure producing devices, which will be explained in detail with
reference to FIGS. 2A, 2B and 3. A respective pressure pulse is
exerted on the additive in the respective additive passage duct 24
by the pressure producing devices so that for each pressure pulse
one drop of additive is expelled into the pressure medium flow duct
10 at the respective outlet 25. The additive drops are indicated in
the drawing with a collective index 31. After leaving the outlets
25 the additive drops 31 are directed by a baffle means, which in
FIG. 1 is a baffle plate 32, in the pressure medium flow duct 10 in
the direction 13 of the arrow and distributed in the pressure
medium.
[0030] By way of a supply line 33, which pressure medium enters by
way of an opening 34, the additive supply containers 27 through 30
are subjected to pressure medium so that the additive is forced out
of the supply containers 27 through 30 into the supply line 26 and
accordingly into the additive passage ducts 24. Such an arrangement
for the supply of additive can be termed pseudo isobaric, because
the factors in the flow duct 10 directly act on the additive
supply. It is also possible for a pressure reducing means to be
provided on the supply line 33. Furthermore, it is possible for the
supply line 33 not to open into the flow duct 10 but into the
surroundings so that additive will be forced by the pressure of the
surroundings into the supply line 26 from the supply containers 27
through 30.
[0031] The pressure producing devices in the additive passage ducts
24 are controlled by the control means 21 by way of connection 23
and connections, not illustrated, located within the injection head
22. As an input signal for the control of the pressure producing
devices the control means 21 evaluates the data from the sensors 17
and 18. When the sensors 17 and 18 are for instance pressure
sensors, a pressure gradient will be produced between these sensors
during flow through the flow duct 10 of pressure medium, and from
such pressure gradient the control means 21 finds the instantaneous
flow rate in the pressure medium flow duct 10. If the flow rate is
great, the requirement for additive to be injected in the flow duct
10 will also be large and the control means 21 will so control
pressure producing devices in the additive passage ducts 24 that
same inject numerous drops of additive in the flow duct 10. In this
case the control means 21 will for instance apply high frequency
voltage pulses to the pressure producing device.
[0032] It is also possible for the control means 21 to be
instructed by a higher order control, represented by an arrow 35,
to produce a certain concentration of additive into the flow duct
10. Furthermore it is also possible for a local lower order control
to be integrated in the injection head 22, which controls the
respective pressure producing devices locally in a manner dependent
on commands, which are provided by the control means 21.
[0033] FIG. 1 furthermore shows a heating means 36 which is
indicated in the form of a heating spiral diagrammatically. In the
example of FIG. 1 the heating spiral acts on the supply line 26 and
heats the additive in the supply line 26 so that a certain
viscosity of the additive may be set in the additive passage ducts
24 or the flow duct 10. It is also possible for a cooling means to
be arranged on the supply line 26 instead of the heating means 36
or in addition to it, in order to lower the temperature of the
additive in the supply line and thus produce a certain viscosity of
the additive.
[0034] Furthermore the heating means or the cooling means 36 as
well may be arranged directly inside the injection head 21,
preferably near the additive passage ducts 24 so that adjacent to
the outlets 25 the desired viscosity of the additive is ensured.
Preferably then temperature sensors are provided in the vicinity of
the additive passage ducts and as near as possible to the outlets
25, such sensors rendering possible regulation to get to the
desired temperature. The heating means or, respectively, cooling
means 36 can be controlled by the control means 21. Furthermore the
temperature sensors may be connected in the vicinity of the
injection head 22 with the control means 21. Preferably the
injection head 22 or even the entire additive atomizing device
illustrated in FIG. 1 is arranged in a housing thermally insulated
from the outside.
[0035] With reference to FIGS. 2A and 2B the following will
describe one example of a design of an additive passage duct, as
for instance an additive passage duct 24 of the injection head 22
as in FIG. 1. In FIGS. 2A and 2B the additive the passage duct 24
is illustrated in the form a chamber, which is constituted
respectively by wall parts 37, 38, 39 and 40 having an L-like cross
section. Between the wall parts 37 and 38 there is an inlet 41
through which the additive passes from an additive supply line, not
illustrated, and for instance the supply line 26, to the additive
passage duct 24. By the wall parts 37 and 40 an overflow 42 is
delimited, by way of which excess additive may flow out of the
additive passage duct 24 into an overflow region, not
illustrated.
[0036] The wall parts 38 and 39 hold a blade 43, which is made in
two layers of piezoelectric material.
[0037] The blade 43 has electrical contact elements 44 and 45, to
which a voltage may be applied, f. i. by the control means 21. If
such a voltage is applied, the blade 43 will deform. Between wall
parts 39 and 40 there is the outlet 25 and in the working examples
of FIGS. 2A and 2B is in the form of a group of nozzles with a
plurality of closely adjacently outlet openings. To the rear and
furthermore to the front, that is to say at plane behind the plane
of the drawing and in front of the plane of the drawing the
additive passage duct 24 is delimited by walls, not illustrated in
FIGS. 2A and 2B. It is also possible for several additive passage
ducts 24 to be arranged one after the other, to be supplied by a
common inlet 41 with additive and to have a common overflow 42, one
respective blade 43 acting on a output 25 with respectively one
nozzle group.
[0038] If a voltage is applied to the electrical contact elements
44 and 45 the blade 43 will move away from the outlet 25 in the
form of a group of nozzles. The space then produced underneath the
blade will fill with additive. In order to prevent the additive
taking the shorter path back through the inlet 41 or the overflow
42, chokes are provided here, not illustrated. Therefore the
contact elements 44 and 45 are short circuited so that the blade 43
swings back into its initial position forcing additive through the
outlet. Such a condition is illustrated in FIG. 2B. Fine drops of
additive are then formed at the outlet openings of the outlet 25
and distribute themselves in the pressure medium in the flow duct
10, which is not illustrated in FIGS. 2A and 2B. By the brief
application of voltage to the electrical contact elements 44 and 45
and by the following short circuiting of the electrical contact
elements the blade 43 will be caused to perform a paddling movement
in relation to the outlet 25 so that very fine drops or droplets of
additive will be formed at the outlet 25 in a manner dependent of
the frequency and size of the voltage at the elements 44 and 45 and
such drops will be injected into the pressure medium flow duct
10.
[0039] As indicated supra it is possible for the blade 43 to be
shifted away from the outlet 25 or toward it out of the position
illustrated in FIG. 2A by the application of voltage to the
electrical contact elements 44 and 45. For this purpose a square
pulse is f. i. suitable, so that during the rise of the leading
edge of the pulse the blade will be moved away from the output 25
and during its constant level phase the blade will be held for a
short time in the position remote from the outlet 25, while
corresponding to the trailing edge of the pulse the blade will
swing toward the outlet 25. The basic square signal of the voltage
pulse can be modified in the following manner for metering the
additive at the outlet 25:
[0040] pulsed operation: packets of identical square pulses, which
are generated with the same frequency, are applied to the blade 43.
By varying the number of the square pulses in a packet or the
intervals between the respective packets it is possible to control
the quantity of additive leaving by way of outlet 25.
[0041] pulse width modulation: the additive metering rate at the
outlet 25 is controlled by changing the width of the square pulses.
It is also possible to vary the time interval between square
pulses. Modulation forms in the case of which both the width of the
square pulse and also the intervals between same are varied are
also possible.
[0042] Amplitude modulation" Here the square pulse will
respectively have the same width and will be produced with the same
frequency, but the height of the square pulses (voltage) will be
varied. In a similar manner the deflection of the blade 43 in
relation to the outlet 25 and accordingly the quantity of additive
injected through the outlet 25 is varied.
[0043] Hybrid forms of the above mentioned types of modulation and
of pulsed operation are just as possible as other forms of
influencing the square pulses.
[0044] In order to prevent dribbling of additive through the outlet
25 when the additive atomizing device is turned off, it may be
necessary to seal off the outlet 25 when the system is not
operating. This may be achieved by coating the blade 43 on the side
facing the outlet 25 with a suitable sealing material, the blade
being suitably biased to lie against the outlet 25. However owing
to the possibility of fracture of the blade same should not impact
against outlet 25 during ejection motion.
[0045] Such impact may be prevented in the following fashion: The
blade 43 is at a distance from the outlet 25 in its resting
position so that the blade 43 may somewhat overshoot the resting
position. FIG. 2A shows the blade 43 in the resting or neutral
position. For the sealing effect on the outlet 25 a negative
voltage must be applied to the electrical contact elements 44 and
45 to deflect the blade 43 toward the outlet 25 till it makes
contact. This condition is illustrated in FIG. 2B. As an
alternative the blade 43 could also be so mechanically biased that,
as indicated in FIG. 2B, it contacts the outlet 25 in the neutral
position. The blade 43 must therefore be operated with an offset
voltage, which prevents impact of the blade 43 against outlet 25
during operation. In the center position of the swinging motion the
blade is then moved clear of the outlet 25.
[0046] As shown in FIGS. 2A and 2B the additive passage duct 24 and
an injection head, which comprises such an additive passage duct,
may be made extremely compact, namely of the order of size of some
micrometers. Accordingly it is possible to directly incorporate the
additive passage duct 24 in a fluid technology device, as for
example a pneumatic cylinder. Thus additive may always be supplied
to the pneumatic cylinder in a systematic manner at the start of
its working stroke. Even incorporation in a microvalve arrangement
would readily be possible.
[0047] FIG. 3 shows a still further possible working embodiment of
the additive passage duct 24 and of a pressure producing device. In
FIG. 3 the additive passage duct 24 is an elongated and preferably
capillary duct from which in the direction 46 additive is supplied,
for instance from the supply line 26. In the additive passage duct
24 there is a heating resistor 47 to which by way of electrical
contact elements 44 and 45 as in FIGS. 2A and 2B square pulses may
be applied by the control means 21.
[0048] Such a square pulse will heat the resistor 47 for a short
time so that a vapor bubble 48 will be formed in the additive and
an additive drop 50 will be ejected in the direction 49 from the
outlet 25. During the trailing edge of a square pulse and during
the resting or neutral phase the resistor 47 will cool down again
so that the vapor bubble present in the additive passage duct 24
will condense again. Then additive will be drawn by the capillary
effect of the additive passage duct 24 from the direction 46 into
the additive passage duct 24.
[0049] It is also possible for a working fluid such as water to be
located over the heating resistor 47 which is held by a diaphragm
over the heating resistor 47. If the water is heated for a short
time by the heating resistor 47 a vapor bubble will form, which
stretches the diaphragm and causes expulsion of the drop 50 of
additive. In this case the physical properties of the additive are
irrelevant, since production of the vapor bubble is only dependent
on the quality of the working fluid. Furthermore, the heating
resistor can not be damaged by chemical or physical action of the
additive.
[0050] FIG. 4 shows the injection head 22 directly, that is to say
without an intermediately placed supply line 26, connected with a
cartridge-like supply container 51, which is filled with additive.
An inlet 52 of an additive supply duct 53 opens into the supply
container 51 to supply additive passage ducts 24, of which in the
example of FIG. 4 there are three arranged in parallelism in the
injection head 22. Outlets 25 of the additive passage ducts 24 open
into a pressure medium flow duct not illustrated in the figure. The
injection head 22 may be either joined in a fixed manner, for
example by bonding, to the container 51 or may be detachable, there
then being for instance a screw or bayonet joint.
[0051] In the additive passage ducts 24 there is a respective
heating resistor 47, as already described in connection with FIG.
3, with which a vapor bubble may be produced in the respective
additive passage ducts 24. As an alternative however piezoelectric,
magnetostrictive or memory metallic blades or diaphragms, as
described in connection with FIGS. 2A and 2B, may be arranged in
the respective additive passage ducts 24 as pressure producing
devices. Connection lines 54 run from the heating resistors 47 to
the electrical contact elements 55, with which for instance the
connection line 23 for the control means 21 may be connected. The
injection head 22 has a screw thread 56 for screwing into the wall
of a pressure medium flow duct, for example into the wall 11 of the
pressure medium flow duct 10. Alternatively however a plug, detent
or bayonet connection would for example be possible too.
Furthermore the injection head 22 possesses a sensor 57, which is
connected by way of a connection line 58 with an electrical contact
element 59. By means of the sensor 57 it is for example possible to
detect the pressure or temperature in the respective pressure
medium flow duct. By way of the electrical contact element 59 the
sensor 57 may be joined with the control means 21.
[0052] FIG. 5 essentially shows the additive atomizing device as in
FIG. 1, in which case however instead of the supply containers 27
through 30 two of the cartridge-like containers 51a and 51b, as in
FIG. 4, each with an injection 22a and 22b, are arranged on the
flow duct 10. The injection heads 22a and 22b are respectively
illustrated in a highly simplified manner and respectively have
only one additive passage duct 24. In both additive passage ducts
there are heating resistors, not separately referenced, or blades
for the production of pressure pulses. The pressure producing
devices are respectively controlled by way of a connection 60 and,
respectively, 61 by the control means 21.
[0053] As shown in FIG. 5 the injection head 22a is in operation
and injects additive into the flow ducts 10. The injection head 22b
is on standby and may be switched by the control 21 in the case of
there being a greater additive requirement in the flow duct 10.
This means that it is extremely simple to replace respectively one
of the cartridges 51a and 51b in the non-active state alone or in
combination with the respective injection head 22a and 22b and so
replace spent additive.
[0054] Owing to the oblique setting of the flow ducts 24a and 24b
the deflection baffle plate 32 in FIG. 1 may be unnecessary. It is
also possible for the additive to be injected perpendicularly to
the flow direction 13 of the pressure medium and only be deflected
by the flow of the pressure medium and simultaneously distributed
in the flow duct 10.
[0055] Furthermore a sensor 62 is arranged in the flow duct 10,
which passes on data by way of a connection 63 to the control means
21. For instance, additive may deposit on the sensor 62 so that the
electrical conductivity at the surface of the sensor 62 changes.
The sensor 62 can measure this surface resistance and pass it on to
the control 21. The latter then finds the respectively current
concentration of additive on the basis of the respective resistance
value. The control means 21 can therefore so drive the pressure
producing devices that there is an even additive concentration in
the flow duct 10.
[0056] The control means 21 can also be subject to a target value
for the additive concentration coming from an external control, for
example by way of a field bus connection or a corresponding
parametric synthesis. In addition or as an alternative it is
possible for the control means 21 to evaluate the flow rate as
found by the sensors 17 and 18, of the pressure medium in the flow
duct 10 to provide for suitable control of the pressure producing
devices in the injection heads 22a and 22b. The sensor 62 or the
sensor 52 illustrated in FIG. 4 may also measure the temperature in
the flow duct 10, dependent on which the control means 21 then
drives the pressure producing devices.
* * * * *