US20030000773A1

US20030000773A1 - Additive nebulising device

Info

Publication number: US20030000773A1
Application number: US10/181,618
Authority: US
Inventors: Wolfgang Engler; Manfred Zindl; Michael Sonn; Michael Berner
Original assignee: Festo SE and Co KG
Current assignee: Festo SE and Co KG
Priority date: 2000-01-21
Filing date: 2001-01-13
Publication date: 2003-01-02
Also published as: DE50110151D1; ATE330166T1; JP2003520932A; EP1248927A1; WO2001053741A1; DE10002414A1; EP1248927B1

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).

Description

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.

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.

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.

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.

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.

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.

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.

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.

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.

Further convenient developments of the invention are defined in the dependent claims.

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.

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.

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.

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.

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.

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.

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.

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.

Working examples of the invention will be now described with reference to the accompanying drawings. [0019]
FIG. 1 diagrammatically shows a first working example of an additive atomizing device in accordance with the invention. [0020]
FIG. 2A shows a additive passage duct in the form of a chamber with a blade as an actuator. [0021]
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. [0022]
FIG. 3 shows an additive passage duct in the form of a capillary with a heating element. [0023]
FIG. 4 diagrammatically shows a working example of an injection head with a cartridge connected with it. [0024]
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.[0025]
FIG. 1 shows an additive atomizing device having a pressure [0026] 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.
The pressure [0027] 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.
The control means [0028] 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.
In the [0029] 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.
By way of a [0030] 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.
The pressure producing devices in the [0031] 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.
It is also possible for the control means [0032] 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.
FIG. 1 furthermore shows a heating means [0033] 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.
Furthermore the heating means or the cooling means [0034] 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.
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 [0035] 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.
The [0036] wall parts 38 and 39 hold a blade 43, which is made in two layers of piezoelectric material.
The [0037] 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.
If a voltage is applied to the [0038] 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.
As indicated supra it is possible for the [0039] 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:
pulsed operation: packets of identical square pulses, which are generated with the same frequency, are applied to the [0040] 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.
pulse width modulation: the additive metering rate at the [0041] 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.
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 [0042] blade 43 in relation to the outlet 25 and accordingly the quantity of additive injected through the outlet 25 is varied.
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. [0043]
In order to prevent dribbling of additive through the [0044] 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.
Such impact may be prevented in the following fashion: The [0045] 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.
As shown in FIGS. 2A and 2B the [0046] 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.
FIG. 3 shows a still further possible working embodiment of the [0047] 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.
Such a square pulse will heat the [0048] 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.
It is also possible for a working fluid such as water to be located over the [0049] 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.
FIG. 4 shows the [0050] 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.
In the [0051] 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.
FIG. 5 essentially shows the additive atomizing device as in FIG. 1, in which case however instead of the [0052] supply containers 27 through 30 two of the cartridge-like containers 51 a and 51 b, as in FIG. 4, each with an injection 22 a and 22 b, are arranged on the flow duct 10. The injection heads 22 a and 22 b 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.
As shown in FIG. 5 the injection head [0053] 22 a is in operation and injects additive into the flow ducts 10. The injection head 22 b 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 51 a and 51 b in the non-active state alone or in combination with the respective injection head 22 a and 22 b and so replace spent additive.
Owing to the oblique setting of the flow ducts [0054] 24 a and 24 b 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.
Furthermore a [0055] 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.
The control means [0056] 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 22 a and 22 b. 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.

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).