Patent Grant
7341208
1. Field of the Invention
The invention relates to an atomizer for a fluid whose droplets are precipitated onto a surface. The atomizer can atomize aqueous and non-aqueous fluids, emulsions and suspensions, solutions, dyes and oils. The atomizer can be miniaturized, and it can also contain micro-structured elements.
The atomizer according to the present invention does not require a propellant gas, can be actuated manually, and can be adapted to the properties of various fluids that are to be atomized, as well as to the planned application of the atomized fluid.
2. Description of the Related Art
Atomizers are known where the fluid under pressure contains a propellant (e.g., a liquefied propellant gas) with which the fluid is atomized upon exiting through a nozzle, such as by the influence of the evaporating propellant. Known propellants include gases that are physiologically hazardous, pollute the environment, or are flammable. The container for the fluid must withstand the gas pressure, possibly even at elevated temperatures, and be tight against the gas pressure. If during storage of the container, which is generally filled partially with the fluid, or during usage of the atomizer, the valve on the container is not sufficient gas-tight and the gas pressure drops due to the partially leaking gas, the usefulness of the container or the atomizer can be limited.
Atomizers are known in which the fluid is pushed through a nozzle by a pump, which is manually actuated by the operator, and is thus atomized. The pressure applied to the fluid that is to be atomized, and thus the distribution of the droplet size, is dependent upon the force with which the operator actuates the pump. Thus the pressure at which the fluid is atomized is dependent upon the behavior of the user. Actuation of such an atomizer can be difficult for a person lacking practice when the atomized fluid is supposed to be deposited at a specified location (for example on the skin of the user).
Another known atomizer includes an air pump and a container for the fluid that is to be atomized. The air pump includes a piston, which is moved manually back and forth inside a cylinder. Air flows out from a hole in the bottom of the cylinder. The fluid container is attached to the cylinder, which is equipped with a thin immersion tube, extending into the fluid in the fluid container. The other end of the immersion tube is located directly next to the hole in the bottom of the cylinder. The axis of the immersion tube is vertical in relation to the direction in which the air current exits the cylinder. With sufficient speed of the air flowing out of the container, the fluid experiences a suction effect and is carried along in the air current and atomized. The amount of fluid taken in during one stroke of the piston, and the distribution of the droplet sizes, depends on the speed with which the air exits the hole in the bottom of the cylinder. Both features are difficult to reproduce.
In the known atomizer with a manually actuated pump, the delivery amount and the average droplet size are dependent upon the behavior of the user. The pressure that can be attained is relatively low and is typically less than 0.8 MPa (8 bar). With whirl chamber nozzles, whose outlet orifices have a diameter of more than 300 micrometers, a discharge quantity that is suitable for the application purpose can be achieved with a relatively large mean or average particle size.
A miniaturized high-pressure atomizer is known from WO 97/12687, with which small quantities, e.g. 15 microliters, of a fluid can be atomized at a pressure of 5 to 60 MPa (50 to 600 bar), preferably 10 to 60 MPa (100 to 600 bar). The hydraulic diameter of the nozzle duct is less than 100 micrometers, preferably 1 to 20 micrometers. In the aerosol that is generated, the mean droplet diameter is less than 12 micrometers. The distribution of the droplet size can be adjusted in a reproducible manner. The aerosol can reach the lung, for example through inhaled air. However, the fluid droplets are difficult to precipitate from the air current onto a surface that meets with the aerosol-containing air current.
In WO 97/20590 a locking-stressing mechanism is described, which can be used for stressing a spring in a spring-actuated atomizer. The atomizer contains two housing parts, which are seated rotatable relative to one another. A helical spring is used for example as an energy storage means, which can be manually placed under tension with a screw-thrust transmission means by rotating the two housing parts toward each other. The locking-stressing mechanism is triggered manually by actuating a release button and displaces a piston in a cylinder, thus releasing a partial quantity of a fluid through a nozzle and atomizing it.
The present invention can provide a propellant-free atomizer, with which a partial quantity is atomized from a supply of fluid discontinuously, which is suited for a purely manual actuation, and with which the distribution of the droplet size in the atomized jet can be adjusted in a reproducible manner independent of the experience and the behavior of the person operating the atomizer, and which can include the following elements within a housing:
a storage container and a nozzle for the fluid that is to be atomized as well as a cylinder with a piston that can be displaced therein,
a hollow chamber within the cylinder in front of the piston, which is connected with the storage container via an intake duct and with the nozzle via a discharge duct,
a valve at least in the intake duct, and
a drive device for the piston,
wherein
the drive device comprises an energy storage means or device for mechanical energy, which is arranged outside the storage container, and the force that is applied by the energy storage device acts upon the piston, and
a device for manually feeding mechanical energy into the energy storage device, and
the nozzle is a swirl nozzle, which provides the fluid flowing through the nozzle with circulation.
The swirl nozzle can be designed as a spiral housing and contain a whirl chamber, into which the fluid is fed tangential to the inside wall. The fluid exits the nozzle through a nozzle outlet duct, which is located in the center of the whirl chamber. The mean inside diameter of the whirl chamber is larger than the diameter of the outlet duct. On this swirl nozzle, an angle of about 90 degrees is formed between the direction of the fluid that is introduced into the whirl chamber and the direction of atomized jet leaving the nozzle.
In another embodiment, the swirl nozzle can contain a cylindrical hollow chamber, in which a cylindrical body is incorporated. In the intermediate space between the exterior of the cylindrical body and the interior of the hollow chamber of the swirl nozzle a guiding mechanism in the form of a helix is integrated. The fluid is introduced parallel to the axis of this swirl nozzle. Due to the guiding mechanism, the fluid experiences circulation. The fluid exits through a nozzle outlet duct, which is located on the axis of the swirl nozzle. In the swirl nozzle the outlet direction of the fluid is parallel to the inlet direction of the fluid. The guiding mechanism includes a bar that is wound helically, which is preferably arranged on the shell area of the cylindrical body and rests tightly against the inside wall of the cylindrical hollow chamber. The bar can take on the shape of a single-thread or a multiple-thread screw.
The nozzle duct of the swirl nozzle can have a diameter of between about 30 micrometers to about 300 micrometers, preferably from between about 50 micrometers to about 150 micrometers. The nozzle duct can have a length of between about 10 micrometers to about 1000 micrometers, preferably from between about 50 micrometers to about 300 micrometers. The mean inside diameter of the whirl chamber in the swirl nozzle or the diameter of the cylindrical hollow chamber of the swirl nozzle can be between about two (2) to about ten (10) times, and preferably between about two-and-a-half (2.5) to about five (5) times, as large as the diameter of the nozzle duct.
The drive device for the piston includes a storage unit for mechanical energy. The energy storage device can be a spring, preferably a helical spring or disk spring, which acts as a pressure spring. The spring can include metal or polymer. A gas spring can also be used, preferably a hermetically closed roll bellows gas spring.
These springs can be pre-stressed during installation in the atomizer. The helical spring and the disk spring are brought to the specified spring tension. The gas spring is compressed to the desired gas pressure.
The spring is placed under tension manually (i.e., a length of the spring is decreased to compress the spring). The spring, acting as a working spring, stores the energy used for displacing the piston inside the cylinder for ejecting and atomizing the fluid.
For the purpose of stressing the working spring, the piston can be equipped with a rod, which protrudes out of the housing. When the rod is manually pulled out of the housing with a handle to a certain degree, the working spring is simultaneously stressed, the piston is pulled out of the cylinder to a certain degree, and fluid is sucked into the chamber within the cylinder from the storage container.
Furthermore the working spring can be placed under tension by pushing the housing together, possibly with only one hand, when the housing includes two parts, which are connected with each other and are rotatable relative to each other axially.
If the force used for stressing the working spring manually is large, the housing of the atomizer can include two parts, which are connected with each other and are rotatable relative to each other. The drive device can include a screw-thrust transmission means, via which the necessary mechanical energy is fed manually to the energy storage device. The two housing parts are turned manually relative to each other. The screw-thrust transmission means stresses the working spring. For force transformation purposes a force is required that is smaller than the force that is required for pulling out the rod that is attached to the piston in the axial direction.
The energy stored in the working spring exerts onto the partial quantity of fluid inside the cylinder a pressure that ranges from between about 0.5 MPa to about 5 MPa (from 5 bar to 50 bar), preferably from between about 2 MPa to about 3 MPa (from 20 bar to 30 bar).
The drive device can be equipped with a locking mechanism, which includes a locking member and a release button and which keeps the piston in a specified position upon stressing the working spring. This way, a period of time can pass between manually tensioning the working spring and triggering the atomizing process by actuating the release button. During this period of time the atomizer can be brought from the position that is used for the manual stressing of the working spring into the position in which the atomizer is used during the atomizing process.
The drive device with locking mechanism can be designed as a locking-stressing mechanism, which automatically assumes the locking state when the piston reaches a specified position during the tensioning process of the working spring.
In a drive device without locking mechanism, the atomizing process directly follows the process of placing the working spring under tension if, in the ejection duct for the fluid, no valve or an automatically operating valve is installed. The effect of a drive device with locking mechanism can also be accomplished when a valve is incorporated in the ejection duct that is opened manually for the fluid.
The atomizer can include a valve at least in the intake duct, preferably an automatically operating valve. The automatic valve opens at low pressure as the piston is pulled out of the cylinder when stressing the working spring. This valve closes when the piston is pushed into the cylinder by the working spring, and the atomizing process begins. This valve prevents fluid from flowing back into the storage container during the atomizing process.
In the ejection duct another valve (e.g. an ejection valve) can be used if air is simultaneously taken in through the ejection duct in the case of a relatively large cross-section of the nozzle duct in the swirl nozzle during the intake process of fluid from the storage container. This valve can be an automatically operating valve, which prevents the intake of air through the swirl nozzle. The valve opens as the piston begins expelling the fluid through the ejection duct.
The valve in the ejection duct can be a non-automatic valve, which is not opened by the maximum pressure generated by the piston, but opens upon manual actuation. Such a valve in the ejection duct has a similar effect on the handling of the atomizer as does a locking mechanism in the drive device. The fluid located in the cylinder can be atomized between two stressing processes of the working spring, successively in smaller quantities. The valve in the ejection duct can be operated successively several times. The user can determine the amount of fluid that is atomized during each actuation of the valve in the ejection duct to the particular requirements. However, the working spring is placed under tension again when the fluid in the cylinder has been completely ejected the working spring can be stressed before the fluid located in the cylinder has been completely ejected.
In another embodiment of the atomizer, the path of the piston can be shorter than the path by which the working spring is compressed during the tensioning process. When pulled out, the piston impacts with a stop before the working spring is compressed in the manner specified. In the stressed state of the working spring, an intermediate space is created between the movable end of the working spring and the outside of the piston. When triggering the working spring, the working spring exerts an impact on the piston when the movable end of the working spring rests against the outside of the piston. Thus, a pressure surge can be exerted on the fluid in the cylinder.
In the case of an atomizer that is equipped with an automatically operating valve in the ejection duct, the locking mechanism can be equipped with a stop device, which stops the motion of the piston once or more after the piston has traveled a specified distance and before the entire fluid contained in the cylinder has been ejected. Thus, the fluid contained in the cylinder can be ejected successively in several portions, which can be adjusted in a reproducible manner, and be atomized. The atomizer can be actuated several times between two tensioning processes of the working spring. The stop device can stop the motion of the piston at previously established and subsequently fixed positions of the piston. The stop device can be adjusted and actuated from the outside. Thus, the positions of the piston at which the stop device stops its motion can be subsequently adjusted and modified.
In order to place the partial quantity of fluid removed from the storage container under pressure, a device with a movable bellows can also be used. The bellows is stretched by a tensile force, thus increasing its volume and extracting a portion of the fluid from the storage container via an intake duct and an automatically acting valve. When pressing the bellows together in the longitudinal direction, the pressure on the fluid contained therein is increased until the automatically acting valve located in the ejection duct opens and fluid is expelled through a nozzle and atomized.
A single-jet nozzle with a single nozzle duct, which can include a baffle element that is arranged in front of the nozzle, or a multiple-jet nozzle with several parallel or crossing fluid jets, can be used as atomizing nozzles.
The single-jet nozzle contains a single nozzle duct, which has a hydraulic diameter of between about 10 micrometers to about 200 micrometers, and which is between about 20 micrometers to about 1000 micrometers long.
The multiple-jet nozzle can contain several nozzle ducts, the axes of which can run parallel to each other. This way the amount of fluid to be atomized within a specified time can be increased. Furthermore the cross-sectional surface of the atomized jet can be increased, or the shape of the spray pattern can be adjusted to a specified shape. The hydraulic diameter of the nozzle ducts can be the same in all ducts of a multiple-duct nozzle and range from between about 10 micrometers to about 200 micrometers, with a duct length of between about 20 micrometers to about 1000 micrometers, respectively. However, different diameters for the ducts can be used in a multiple-jet nozzle.
The multiple-jet nozzle can also contain at least two nozzle ducts that are tilted relative to each other, which direct the fluid jets to a point in front of the nozzle's exterior at which the fluid jets rebound with each other. The angle between two tilted fluid jets can be between about 30 degrees to about 120 degrees. Due to the rebounding of several fluid jets with each other, atomization can be promoted. The hydraulic diameter of the two nozzle ducts in a two-jet nozzle is preferably less than about 180 micrometers, and is preferably between about 70 micrometers to about 100 micrometers, with a duct length from between about 20 micrometers to about 1000 micrometers, respectively.
A baffle element which rebounds with the fluid jet can be arranged at a distance of between about 0.1 millimeters to about 5 millimeters in front of the nozzle opening. A spherical or hemispherical object can be used in the baffle element, with a diameter of between about 0.1 millimeters to about 2 millimeters. In the case of a hemi-spherical ball, the fluid jet preferably rebounds on the convex side. Furthermore a baffle plate or a baffle cone can be used, wherein the fluid jet strikes the baffle plate vertically or at the tip of the cone, for example. A baffle element can promote atomization of the fluid. The baffle element can also create a largely ring-shaped spray pattern. The direction of the atomized jet can be inclined towards the axis of the nozzle ducts when the jet before atomization rebounds at an angle with the plate. Where several nozzle ducts are arranged parallel to each other, one or more baffle elements can be provided, which can influence the shape and size of the atomized jet and the direction of the atomized jet.
The baffle element can be fastened to the housing of the atomizer with at least one fastening element. Suitable fastening elements include a rigid wire or a rod. However, the baffle element can be fastened to the housing with two or three fastening elements. If the length of the fastening elements is varied, the distance from the baffle element to the outside of the nozzle can be changed.
The mass flow rate occurring in the nozzle duct of the atomizer according to the invention can be less than about 0.4 grams per second. The mean droplet diameter can be less than about 50 micrometers.
The atomizer of the present invention can provide the following advantages:
The sequence of the atomization process, the mass flow of the fluid through the nozzle duct and the distribution of the droplet size are independent of the force applied by the user when stressing the working spring. These features are established by the design of the atomizer and are reproducible.
Alcohol or other volatile hydrocarbon compounds are not required for atomizing the fluid.
The jet exiting the atomizer can include only the air carried along from the surroundings as a gas component.
The distribution of the droplet size and the mass flow of the fluid exiting the atomizer can result in an atomized fluid jet that is suited for the precipitation of droplets on a surface that is struck by the atomized fluid jet.
The atomizer can be manufactured in various versions and be adapted to the intended application purpose and for favorable handling.
Examples of the atomizer according to the present invention are explained in more detail based on the following figures.
A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
a shows a partial top view of a whirl chamber nozzle.
b shows a longitudinal cross-sectional view of the whirl chamber nozzle along the line A-A of
c shows an enlarged view of the nozzle duct of
a shows a longitudinal cross-sectional view of the second embodiment of the swirl nozzle.
b shows an oblique view of the cylindrical body incorporated in the chamber of the second embodiment of the swirl nozzle.
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, an example of the present invention is described below referring to the figures.
The housing 1 of a rigid material contains a hollow chamber 2, in which a pre-stressed helical spring 6 is disposed. The helical spring 6 is supported on one end by the bottom of the hollow chamber 2, and pushes with the other end on a piston 3. A thinner part of the piston 3 is displaceable in the cylinder and sealed against a cylinder wall. A hollow chamber 4 is located within the cylinder in front of the thinner part of the piston 3, into which fluid can be drawn. The hollow chamber 4 is connected with a storage container 10 for the fluid that is to be atomized via an intake duct 11. The intake duct 11 can include an automatically operating spring-loaded intake valve 13, through which the fluid can flow out of the storage container into the hollow chamber 4 during the intake process. The storage container 10 can be a collapsible bag, which is arranged in a hollow chamber 15 within the housing 1. The hollow chamber 15, which is closed with a cover, is provided with an opening 27, through which ambient air can flow in to compensate for differences in pressure caused by a decrease in the volume of the collapsible bag. The hollow chamber 4 is connected with the nozzle 22 via the ejection duct 21. The ejection duct can include a spring-loaded valve 23, which opens when the fluid that is to be atomized is disposed in front of the valve and has a sufficient high pressure. On its thicker end, the piston 3 is connected with a rod 31, which is surrounded by the helical spring and protrudes from a bottom of the housing. An end of the rod 31 is connected with a handle 32, with which the piston 3 can be pulled manually out of the cylinder to a specified degree or distance, such that the helical spring is tensioned (i.e., a length that the spring is decreased) simultaneously. A stud 33 is arranged on the bottom of the housing, which keeps the rod 31 and thus the piston 3 in the specified positions when the piston is pulled a specified distance out of the housing.
For subsequent stressing of the helical spring 6, the rod 31 and the piston 3 are pulled out by the handle 32 until the stud 33 snaps into a notch 34. By pulling the piston 3 back, a volume of the chamber 4 within the cylinder is increased. Fluid is sucked into the chamber 4 from the storage container 10 via the intake duct 11 when the valve 13 is open. The closed valve 23 prevents air from entering the chamber 4.
The rod 31 can be pulled back with a lever (not shown) that is accessible from the outside and that can be manually operated, whereby the spring is stressed and the chamber 4 fills with fluid. Upon releasing the lever, the tensioned spring concurrently pushes the fluid out of the chamber 4 through the nozzle 22 and atomizes the fluid. Thus, neither the stud 35 nor the notch 34 is required. In this embodiment, the atomizer operates similar to a manually operated pump atomizer (finger pump). The pressure exerted on the fluid contained in the chamber 4 within the cylinder, however, is generated by the tensioned spring in the atomizer, and thus the user has no influence on the exerted pressure.
This atomizer includes features similar to the atomizer of
The atomizer has a cylindrically shaped housing. A lower housing part 51 is rotatably connected with an upper part 52 of the atomizer via a snap-fit connection. The upper part contains a cylinder 53 and a nozzle 60. The upper part is equipped with a removable protective cap 54. By rotating the cap 54 and the thereto connected upper part 52 of the atomizer, a component 55, which is arranged in the lower housing part 51 in an axially displaceable manner and contains the piston 81, is pushed away from the cylinder 53 with a screw-thrust transmission device until a pawl 74 that is arranged in the component 55 is engaged behind a protrusion in the lower housing part 51. During this process, a volume of the chamber 57 within the cylinder is increased. Concurrently, a portion of the fluid 64 is sucked into the chamber 57 from the storage container 63, which can be designed as a collapsible bag, through the duct 68 in the tubular piston 81, and the helical spring 59 is stressed. An automatically operating valve can be disposed in the duct that connects the chamber 57 with the nozzle 60, which includes a ball 70 loaded with a spring 71. The valve prevents air from entering the chamber 57 while receiving the fluid, thereby filling the chamber 57 with fluid that is bubble-free. A valve is attached on an end of the tubular piston 81 that is located within the cylinder 53, which includes of a ball 61 loaded with the spring 62. The spring 62 is kept in its position by a plug that is pushed into the end of the tubular piston 81. The plug can include a duct, through which the fluid flows into the chamber 57. An upper edge 56 of the plug can act to seal the piston 81 against the cylinder 53. The valve on the inner end of the tubular piston 81 can open automatically when fluid is received and can close when fluid is expelled through the nozzle.
To atomize the fluid contained in the chamber 57 within the cylinder, the protective cap 54 is removed and the release button 58 located in the lower housing part is actuated manually to disengage the pawl 74. The stressed helical spring 59 places the fluid contained in the chamber 57 under pressure. The valve that is arranged in front of the nozzle opens automatically. The fluid in the chamber 57 is expelled through the nozzle 60 and atomized. During the process of ejecting the fluid, the valve that is attached on the end of the tubular piston is closed, preventing fluid from flowing out of the chamber 57 back into the storage container 63. After the atomization process has been completed, the protective cap 54 is replaced on the upper part of the atomizer.
When the valve is opened manually in front of the nozzle during actuation, a release button similar to that shown in
A closed container that cannot be deformed and that is equipped with an automatically operating ventilation valve as well as with a immersion tube extending into the container, possibly in the form of a pipe coil, can be used in place of the collapsible bag 63. The seal of the tubular piston against the cylinder by the upper edge 56 of the plug can be replaced with an O-ring, which is attached in a groove in the lower end of the cylinder in a certain place or channel 80.
In another embodiment of the atomizer, the component 55 including the tubular piston can be connected with the lower housing part, and the cylinder with the chamber 57 can be arranged displaceably in the axial direction in relation to the lower housing part 51. For easier handling of the atomizer, a multi-tooth pawl can be provided, which is constantly being snapped into portions of the housing during stressing of the helical spring.
If a relatively great force is required for tensioning the helical spring, a screw-thrust transmission device can be used, which can be rotated through more than 360 degrees. This allows for the requisite manually applied force that is required for placing the helical spring under tension by rotating the two housing parts relative to each other to be reduced considerably.
Within the whirl chamber nozzle 121, the nozzle duct 123 aligned with an axis of the whirl chamber nozzle duct 122, and the fluid that is to be atomized is guided through three ducts 123, for example, tangentially into the whirl chamber 124. The axes of the nozzle ducts 123 intersect the axis of the whirl chamber nozzle duct 122. The nozzle ducts 123 are shown enlarged relative to the whirl chamber nozzle duct 122. The cover plate 125 for the whirl chamber nozzle duct 122 and the nozzle ducts 123 includes an opening 126 in the area of an outer end of the nozzle ducts 123, respectively, through which the fluid enters the nozzle ducts 123.
a shows a longitudinal cross-section through the swirl nozzle 131 having the outlet duct 132. Within the cylindrical hollow chamber 133 of the swirl nozzle the cylindrical body 134 is incorporated. This body includes a helically wound bar 135 in the shape of for example a double-thread screw. The fluid is guided by helically wound grooves 136 and experiences circulation. The inlet direction 137 of the fluid to be atomized is parallel to its outlet direction 138.
b shows an oblique view of the cylindrical body 134 incorporated in the chamber of the second embodiment of the swirl nozzle. The surface of body 134 includes a helical guiding channel in the shape of a double-thread screw.
Obviously, numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 101 54 237 | Nov 2001 | DE | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3185355 | Lipman | May 1965 | A |
| 3771728 | Polnauer | Nov 1973 | A |
| 4071196 | Burke et al. | Jan 1978 | A |
| 4074861 | Magers et al. | Feb 1978 | A |
| 5067655 | Farago et al. | Nov 1991 | A |
| 5405084 | Weston et al. | Apr 1995 | A |
| 5497944 | Weston et al. | Mar 1996 | A |
| 5662271 | Weston et al. | Sep 1997 | A |
| 6413246 | Harrold | Jul 2002 | B1 |
| 6685109 | Py | Feb 2004 | B2 |
| 20030116650 | Dantes et al. | Jun 2003 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20030209238 A1 | Nov 2003 | US |
