Patent Application
20100243672
The present invention relates to aerosol spray cans. More specifically, it relates to a method and device for preventing liquid dispensation from an aerosol spray can.
Aerosol spray cans house and emit chemicals for a variety of purposes. Usually the chemicals are stored within the aerosol spray can as a vapor of a liquid with a boiling point slightly lower than room temperature. This means that inside the aerosol spray can, the vapor can exist in equilibrium with its bulk liquid at a pressure that is higher than atmospheric pressure and able to expel the payload. As the chemicals are dispensed from the aerosol spray can, the chemicals expand from a liquid into a gaseous state as they go from a pressurized liquid state within the aerosol spray can to a non-pressurized gaseous state outside the aerosol spray can. Any dispensed chemicals that were in a gaseous state while housed in the aerosol spray can are immediately replaced by evaporating liquid within the aerosol spray can.
Although the chemicals are typically dispensed from the aerosol spray can in a gaseous state, sometimes the chemicals may be dispensed in a liquid state. For example, if the aerosol spray can is shaken or tilted, it is possible to trap some chemicals in a liquid state within an extension tube that resides in the aerosol spray can. Once inside the extension tube, the chemicals in a liquid state may be dispensed from the aerosol spray can if the user then depresses a trigger or button affixed to the aerosol spray can. Dispensing the chemicals from the aerosol spray can in a liquid state, instead of gaseous state, can not only be wasteful but dangerous as well.
Some aerosol spray cans are used as dust blowing devices. Presently, dust blowing devices generally consist of a pressurized gas source for their stored chemicals, a valve and a nozzle for directing the gas flow. The pressurized gas is used to blow dust or other particles from the surface to be cleaned e.g. floppy disks for computers, lenses for microscopes, cameras and other optical instruments, assembled microchips, consumer electronic devices and other small or hard-to-reach places.
These dust blowing devices typically house chemicals such as chlorofluorocarbons, e.g. Freon (Freon is a trade name for a particular chlorofluorocarbon manufactured by DuPont), or Freon-22, in a pressurized state within the aerosol spray can. When these liquefied chlorofluorocarbons are released from the container, they change to gas and exit the container under pressure. A jet of chlorofluorocarbon gas is thus used to blow dust from the surface to be cleaned. However, in order to ensure that only chlorofluorocarbon gas is released from the container, the container must be maintained in a substantially upright position.
If the can is inverted, liquefied chlorofluorocarbon may escape from the container. For the typical consumer, it is desirable to avoid this. Liquefied chlorofluorocarbons are extremely cold and can cause frostbite if they contact the user's hand. Also, allowing liquefied chlorofluorocarbons to escape from the container results in wasted chlorofluorocarbons. Some dust blowing devices use liquefied hydrofluorocarbons instead of liquefied chlorofluorocarbons. In addition to the above mentioned issues with releasing liquefied chlorofluorocarbons, releasing liquefied hydrofluorocarbons pose an additional danger in that they are flammable as well.
Unfortunately, it is difficult to maintain aerosol spray cans, such as dust blowing devices, in a substantially upright position when directing them on hard-to-reach surfaces, such as in consumer electronic devices. As a result, it would be desirable to have a mechanism within the aerosol spray can which prevents or minimizes liquid dispensation from an aerosol spray can.
In one aspect, an aerosol spray can is provided. The aerosol spray can includes but is not limited to a housing forming a storage chamber, an initial amount of chemical stored in a compressed liquid state within the storage chamber, a valve assembly attached to the housing, and an extension tube connected with the valve assembly at a first end and extending into the storage chamber at a second end. The initial amount of chemical forms a top surface. The general direction of the top surface is perpendicular to the direction of gravity. The valve assembly including a stem forming a central passage through which the chemical dispenses from the storage chamber. The second end of the extension tube remains a distance away from the top surface of the initial amount of chemical regardless of the position of the aerosol spray can.
In one aspect, a method of assembling an aerosol spray is provided. The method includes but is not limited to installing a mounting cup over the storage chamber to seal the storage chamber. The mounting cup is connected with an extension tube which extends into the storage chamber. The extension tube is connected with the mounting cup at a first end and extends into the storage chamber at a second end. The method also includes but is not limited to filling a storage chamber of the aerosol spray can with an initial amount of chemical. A liquefied portion of the chemical forms a top surface, and wherein the general direction of the top surface is perpendicular to the direction of gravity, and wherein the second end of the extension tube remains a distance away from the top surface of the liquefied portion of the chemical regardless of the position of the aerosol spray can.
In one aspect, an aerosol spray can is provided. The aerosol spray can includes but is not limited to a housing, a valve assembly, an extension tube, and a sealing member. The housing forms a storage chamber for storing a chemical in a compressed liquid state. The valve assembly is attached to the housing and includes a stem forming a central passage through which the chemical dispenses from the storage chamber. The stem is movable from a normal position to a depressed position. The extension tube is connected with the valve assembly at a first end and extending into the storage chamber at a second end. The sealing member seals the second end of the extension tube when the stem is in the normal position and unseals the second end of the extension tube when the stem is in the depressed position.
In one aspect, a method of preventing liquid dispensation from an aerosol spray can is provided. The aerosol spray can includes but is not limited to a housing forming a storage chamber for storing a chemical in both a liquid and gaseous state, a valve assembly attached to the housing, and an extension tube connected with the valve assembly at a first end and extending into the storage chamber at a second end. The valve assembly includes a stem forming a central passage through which the chemical dispenses from the storage chamber. The stem is movable from a normal position to a depressed position. The method includes but is not limited to sealing the second end of the extension tube when the stem is in the normal position, and unsealing the second end of the extension tube when the stem is in the depressed position.
The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.
In one embodiment, by insuring that a second end of the extension tube remains a distance away from a top surface of an initial amount of chemical in the aerosol spray can regardless of the position of the aerosol spray can, liquefied chemical can be prevented from exiting the aerosol spray can.
In one embodiment, by placing a sealing member at the second end of the extension tube, where the sealing member seals the second end of the tube when the aerosol spray can is in a normal and unused state, the sealing member prevents chemicals from within the aerosol spray can to enter the extension tube unless the button or trigger is in a depressed or active state. As a result, the amount of chemicals which are dispensed in a liquid state from the aerosol spray can be reduced or minimized.
Referring now to
Chemical 124 may comprise, but is not limited to, a household cleaning chemical such as ammonia, bleach, alkalies, acids, detergents, abrasives, sanitizers, and spirit solvents; a lubricant such as petroleum based products, mineral oils, vegetable oils, or synthetic liquids such as hydrogenated polyolefins, esters, silicone, fluorocarbons; an adhesive such as natural adhesives made from inorganic mineral sources or biological sources, synthetic adhesives including elastomers, thermoplastic, and thermosetting adhesives, and drying adhesives having polymers dissolved in a solvent.
Preferably, within aerosol spray can 100, chemical 124 resides in a compressed liquid state, that is, a state in which the chemical 124 is compressed to a pressure which is greater than atmospheric pressure, or greater than about 110 kPA, so that the chemical 124 is changed from a gaseous to a liquid state. Preferably, chemical 124 is compressed to a liquid state under a pressure of at least 110 kPA at a temperature of at least zero degrees Celsius, and converts back to a gaseous state upon exiting aerosol spray can 100 and reverting back to atmospheric pressure, or reverting back to a pressure of less than 200 kPA. In one embodiment, chemical 124 comprises a chlorofluorocarbon such as Freon or Freon-22 (Freon is a trade name for a particular chloroflourocarbon manufactured by DuPont), hydrofluorocarbons such as HFC-152a, nitrogen, or carbon dioxide. However, one having skill in the art will appreciate that chemical 124 is not limited to these illustrative chemicals and may comprise other chemicals. Preferably, chemical 124 consists generally of HFC-152.
Housing 120 forms a storage chamber 122 for storing chemical 124. Preferably, storage chamber 122 stores chemical 124 in a pressurized state so that chemical 124 resides in both a gaseous and liquid state within the storage chamber 122. In one embodiment, housing 120 is a conventional can, such as a metal can suitable for containing a pressurized chemical in a gaseous and liquid state. Housing 120 includes a slopping upper wall 126, opposed to a bottom cover 128 and a sidewall 130, formed in between and connecting the sloping upper wall 126 with the bottom cover 128. The sloping upper wall 126 forms a curved lip 132 defining an opening 134.
Referring to
Valve assembly 140 is attached to the housing 120 through central opening 148. Preferably, a first portion of the valve assembly 140 resides in the storage chamber 122 and a second portion of the valve assembly resides outside of the housing 120 and storage chamber 122. The valve assembly 140 prevents any amount of chemical 124 from exiting the housing 120 unless the valve assembly 140 is activated. Valve assembly 140 may be activated by depressing a stem 172 of valve assembly, as described herein, or by activating the actuator 160. Upon activation, the valve assembly 140 creates a passageway for chemical 124 residing in storage chamber 122 to exit the housing 120. Valve assembly 140 includes a valve body 150, a gasket 152, a valve plunger 154, a spring 156, and a spring cup 158.
The valve body 150 is formed at its upper end with spaced outward projections 162 under which the pedestal 146 is inwardly crimped at 164 to fixedly mount the valve body 150 to the mounting cup 136. Sidewalls 166 of the valve body 150 fall short of an upper end 168 of projections 162 and present an annular support for gasket 152 which is sealingly disposed between the upper end 168 of the projections 162 and an inside surface of the pedestal 146. Gasket 152 is preferably formed of rubber. Valve plunger 154 is disposed with its head 170 inside the valve body 150.
The upper end of the valve plunger 154 is in the form of a tubular stem 172 which extends up through the gasket 152 and through the central opening 148 in the mounting cup 136. The stem 172 forms a central passage 174 through which the chemical 124 is dispensed from the storage chamber 122. Stem 172 extends from outside the housing 120, through the central opening 148, and into the housing 120. Valve plunger 154 also includes a stem support 176 located in the housing 120 and surrounding head 170 of the stem 172. Preferably, the upper end of the stem support 176 is provided with an annular seat 178 which is biased against and engages the gasket 152, via spring 156, to provide further sealing.
The stem 172 is movable from a normal position shown in
Preferably, radial channels 188 are formed in the tubular stem 172. The radial channels 188 are in alignment with the gasket 152 when the stem 172 is in a normal position, that is, when the actuator 160 is not engaged. By aligning the radial channels 188 with the gasket 152 in the normal position, chemical 124 is prevented from being dispensed from the storage chamber 122. When engaged, the actuator 160 causes the stem 172 to move to the depressed position, downwards towards the opening 148, dispensing chemical 124 from the storage chamber 122 through central passage 174, and out discharge orifice 186.
The extension tube 180 is connected with the valve assembly 140 at a first end 190 and extends further into the storage chamber 122 at a second end 192, opposed to the first end 190. Preferably, the extension tube 180 is snugly telescoped over a tailpiece 194 which is integrally formed with a bottom wall 196 of the valve body 150. The tailpiece 194 forms an opening 198 over which the first end 190 of the extension tube 180 is fit. Preferably, the extension tube 180 is made of a relatively flexible polymer, such as polyethylene or silicone. The extension tube 180 extends a distance D1 into the storage chamber 122, where D1 is the distance from an upper surface of the storage chamber 122 to the second end 192 of the extension tube 180. The second end 192 of the extension tube 180 forms an opening 202 through which chemical 124 enters the extension tube 180.
Referring to
In one embodiment, no more than an initial amount A1 of chemical 124 is stored within the storage chamber 122 in a liquefied form. As a result, there is also no more than the initial amount A1 of the liquefied portion 104 of chemical 124. The initial amount A1 of chemical 124 is the maximum amount of chemical 124 which is placed into the storage chamber 122 upon assembling the aerosol spray can 100. No more than the initial amount A1 of chemical 124 is ever placed within the aerosol spray can 100. The liquefied portion 104 of chemical 124 forms a top surface 102. The top surface 102 forms a generally planar surface which is generally perpendicular to the direction of gravity dG, as illustrated by the arrows labeled dG, within ±5 degrees.
Preferably, the liquefied portion 104 of chemical 124 within the storage chamber 122 has a volume of VC and the storage chamber 122 has a total volume of VT, and a remaining volume VR within the storage chamber is equal to VT minus VC. Even more preferably, the remaining volume VR is always greater than the volume VC of the liquefied portion 104 of chemical 124. In this manner, by insuring that the remaining volume VR is always greater than the volume VC of the liquefied portion 104 of chemical 124, it is possible to design an extension tube 180 having a length such that the second end 192 of the extension tube remains a distance D2 away from the top surface 102, regardless of the position of the aerosol spray can 100. Additionally, since no more than an initial amount A1 of chemical 124 is ever stored within the storage chamber 122, the maximum volume of the liquefied portion 104 can be determined as is labeled VCI. Moreover, the minimum amount of remaining volume VRI can also be determined, where VRI is equal to VT minus VCI. Finally, the amount of chemical 124 placed within the storage chamber 122 can be calculated so that VRI is always greater than VC. This insures that the remaining volume VR to always be greater than the volume VC of the liquefied portion 104 of chemical 124.
Referring to
Referring to
Referring to
Preferably, in the upright position, the second end 192 of the extension tube 180 is a distance D2 away from the top surface 102 of chemical 124, so that no portion of the extension tube 180 is in contact with the chemical 124 when in the upright position. Additionally, when in an upside down position, a position in which the aerosol spray can 100 is generally parallel to and opposite the direction of gravity within ±5 degrees, the second end 192 of the extension tube 180 is a distance D2 away from the top surface 102 of the chemical 124. In the upside down position, it is possible that a portion of the extension tube 180, or the valve assembly 140, is in contact with a liquefied portion 104 of the chemical 124. Finally, when in a sideways position, the extension tube 180 is a distance D2 away from the top surface 102 of the chemical 124, so that no portion of the extension tube 180 is in contact with the chemical 124 when in the sideways position. Preferably, distance D2 varies when going between an upright position, an upside down position, and a sideways position.
During assembly of the aerosol spray can 100, chemical 124 in a liquid form may be filled into the housing 120 either before or after the mounting cup 136 is installed to close off the opening in the upper wall 126 of the housing 120. Subsequently, in addition to chemical 124, a propellant gas, such as CO2 or HFC-152a, which may be slightly soluble in the chemical 124, may be forced into the storage chamber 122 by means of a filling head forcing the propellant gas into space above the chemical 124.
In one embodiment, during assembly of the aerosol spray 100, the storage chamber 122 is first filled with an initial amount A1 of chemical 124, where a liquefied portion 104 of the chemical 124 forms top surface 102, and where the general direction of the top surface 102 is perpendicular to the direction of gravity dG. Either before or after filling the storage chamber with an initial amount A1 of chemical 124, the mounting cup 136 is installed over the storage chamber 122, sealing the storage chamber 122. The mounting cup 136 is connected with the extension tube 180 which extends into the storage chamber 122. The extension tube 180 is connected with the mounting cup 136 at the first end 190 and extends into the storage chamber 122 at the second end 192. By either adjusting the distance D1 the extension tube 180 extends into the storage chamber 122, the distance D3 the extension tube 180 resides from the sidewall 130, the initial amount A1 of chemical 124 stored within the storage chamber 122, or all of these factors, one can insure that the second end 192 of the extension tube 180 remains a distance D2 away from the top surface 102 of the liquefied portion 104 of the chemical 124 regardless of the position of the aerosol spray can 100.
Referring to
Preferably, the aerosol spray can 100 further includes an extension member 210 to synchronize the movements of both the stem 172 and the sealing member 200, so that when the stem 172 is in the normal position, the sealing member 200 is in the sealed position, and when the stem 172 is in the depressed position, the sealing member 200 is in the unsealed position. The extension member 210 is any device which can move the sealing member 200 from a sealed position to an unsealed position when the stem 172 is moved from a normal to a depressed position. The extension member 210 includes rigid members such as rods, and bars; flexible members such as springs, rubber bands, and strings, and electronically activated devices such as wireless radios, electric motors, wires, and switches. Preferably, the extension member 210 is a rigid rod which is connected at a first end 212 with the spring cup 158 and at a second end 214 with the sealing member 200. Preferably, the extension member 210 is connected at a first end 212 with the valve assembly 140 and connected at a second end 214 with the sealing member 200. In one embodiment, the extension member 210 forms a plug 216 at the second end 214 which is connected with and positioned through the sealing member 200. Preferably, the extension member 210 is located in the extension tube 180. In this manner, when the stem 172 moves from the normal to the depressed position, the extension member 210 moves the sealing member 200 from a sealed to an unsealed position.
Referring to
Referring to
In operation the sealing member 200 seals the second end 192 of the extension tube 180 when the stem 172 is in the normal position and unseals the second end 192 of the extension tube 180 when the stem 172 is in the depressed position. In one embodiment, the moving of the stem 172 from the normal to the depressed position, movies the sealing member 200 a distance D4 away from the second end 192 of the extension tube 180.
In the unsealed position, the sealing member 200 forms an opening 204 having a first surface area A1. Preferably, opening 202 has a second surface area A2, and the first surface area A1 is equal to or greater than the second surface area A2. In this manner, the amount of fluid entering the extension tube 180 of the aerosol spray can 100 with the sealing member 200 attached is no less than the amount of fluid entering the extension tube 180 of the aerosol spray can 100 without the sealing member 200 attached.
The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.
While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that other embodiments and implementations are possible within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.
