Cleaning and liquid contact with solids – Processes – Including application of electrical radiant or wave energy...
Reexamination Certificate
1999-02-22
2001-06-12
El-Arini, Zeinab (Department: 1746)
Cleaning and liquid contact with solids
Processes
Including application of electrical radiant or wave energy...
C134S010000, C134S021000, C134S033000, C134S025400, C015S001510, C015S303000, C015S308000, C015S313000
Reexamination Certificate
active
06245154
ABSTRACT:
The invention relates to a process for removing liquid impurities in the form of oils and emulsions adhering to a workpiece with the oils and emulsions possibly containing solid contaminants, in particular chips removed from the workpiece, wherein the workpiece is secured to an apparatus and made to vibrate and an associated apparatus for carrying out the described process comprising a device for securing a workpiece with the device arranged at a base-plate, with liquid impurities like oils and emulsions which possibly may contain solid contaminants, in particular chips, adhering to the workpiece, at least one vibration generator for making the workpiece vibrate.
Workpieces like metallic machine parts, in particular after machining and prior to the next operational step, or prior to the mounting or shipping, are washed from adhering liquids in form of oils or emulsions, and other impurities like adhering chips and grinding dust. According to the state of the art, for this purpose different processes are in use.
In a first process which is widely used and known from practical experience the workpiece is washed in a washing device in a suitable mostly heated washing liquid which often contains solvents, is flushed and subsequently dried and if necessary is sprayed with an appropriate agent, e.g., with a thin layer of oil, to protect it against corrosion. It is disadvantage of this process and this apparatus that the energy requirement is very high, which is at the one hand necessary for heating the washing liquid, and at the other hand is required for the necessary drying of the workpieces by heating. Furthermore for environmental reasons a labor-intensive and expensive treatment and cleaning of the washing liquid is necessary.
From U.S. Pat. No. 3,989,537 a process and a device is known for cleaning engine blocks and similar workpieces by vibration to remove casting and machining swarf. According to this known process, the workpiece is made to vibrate in resonant torsional vibrations about a longitudinal axis. The workpiece may simultaneously be rotated in order to remove the swarf out of the cavities of the workpiece, with the swarf loosened by vibrations from the walls of the workpiece. Furthermore, a vibration cleaning unit is described comprising an elastically supported rotatable frame for clamping and rotating an engine block. At the engine block a small excentric vibrator is attached which may be driven by a motor and which vibrates the engine block in resonant vibrations.
It is a disadvantage of this known state of the art that only workpieces may be cleaned which are completely or at least almost dry. Workpieces with adhering liquids, i.e., oil, may not or not completely be cleaned in this way; as only by the generated vibrations, the adhering liquids and the bound dirt particles may not be removed from the workpiece.
U.S. Pat. No. 4,381,577 describes an apparatus for the removal of dirt particles out of drill holes or cavities in workpieces. For this purpose the workpiece is made to vibrate while simultaneously blowing air through the drill holes or the cavities, whereby dirt particles positioned there are to be removed out of the interior of the workpiece.
Hereby a removal of dirt particles and also liquids out of the interior of workplaces is possible, however, the removed particles and liquids are blown into the environment in an uncontrollable fashion. This results in a contamination of the environment which is not desired, or even harmful.
U.S. Pat. No. 5,145,297 illustrates an apparatus and a process for removing dust and particle-like material from a machined workpiece by means of suction. In an embodiment of the associated apparatus, a suction line with a suction nozzle at the one end thereof is provided, wherein the suction nozzle comprises spacers at the front side thereof by means of which the suction nozzle may contact the workpiece to be cleaned. Therein it is provided that the suction nozzle is approaching the workpiece from below. Furthermore this known apparatus comprises a blowing nozzle built into the suction nozzles with the blowing nozzle blowing ionized gas by means of which an electrostatic charge of the particle-like material to be removed is neutralized and made inert. Additionally, a vibration generator may be placed at the upper side of the workpiece opposing the suction nozzle in order to support the cleaning of the workpiece.
It is a disadvantage of this known state of the art that the apparatus and the process is only suitable for removing dry contaminants from the workpiece. For the removal of liquid contaminants, in particular oils and emulsions which have a high viscosity and a strong adherance, this apparatus and the corresponding process is not suitable. The suction nozzle is not adapted to the contour of the workpiece, whereby only such contaminants may be removed from the workpiece which consist of particles easy to be removed and are only clinging to the workpiece with a small adhesive force. By the fact that the vibration generator is only loosely placed onto the workpiece no defined vibrations in the workpiece are guaranteed, moreover the vibrations generated in the workpiece are more at random and may not be reproduced.
Finally, a process and an apparatus for removing chips from machined workpieces is known from WO 96/24462. Therein the workpiece is arranged at a carrier, and the carrier is made to vibrate such that the workpiece, for a short period of time, is lifted from the carrier, and subsequently hits the carrier under the influence of gravity.
Also this process and the associated apparatus is only suitable for the removal of dry contaminants from the workpiece, like the chips mentioned, liquid contaminants, in particular oils and emulsions, may not be removed from the workpiece. Additionally to the cleaning of the workpiece by vibration, before or after washing process may follow wherein the washing process is accomplished by means of liquids or gases like air. The washing by means of liquids leads to the drawbacks mentioned above. In a washing process by means of gas or air which, for practical reasons, means a blowing of the workpiece, a not-controlled distribution of chips and other contaminants in the environment may result which is not desired.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide a process and an associated apparatus wherein an effective cleaning of workpieces is possible with liquid contaminants in the form of oils and emulsions adhering thereto, wherein solid contaminants may be contained without danger to the environment, with a low energy consumption and at low cost.
The object of the process-related part is attained by generating vibrations with a vibration frequency of between 20 and 100 H
z
, generating vibrations at a part of the apparatus securing the workpiece. Simultaneously subjecting the impurities to suction at the workpiece by an airstream guided through at least one nozzle adapted to the shape of the workpiece, and separating the removed liquid and solid impurities from each other by suitable means and reusing or applying each to a new use.
In the process according to the invention, the advantageous effect is created that liquid contaminants in the form of oils and emulsions may, also be effectively removed by suction. This surprising effect obviously is based thereon that by the vibrations the adhesive force of the liquids to be removed and eventually the particles contained therein, is strongly reduced at the workpiece. Therein the energy requirement for the cleaning and the operation time per workpiece is reduced. Therein it is preferably provided that the vibrations are generated with a vibration frequency of between 20 and 100 Hz. As a surprise, it has been found that particularly in this frequency range, a most effective mobilizing of the liquids or mixtures of liquid and solid contaminants adhering to the workpiece is attained. It is a further advantage of this process according to the invention that the vibrations in the above frequency range to be ge
El-Arini Zeinab
Sonnenschein Nath & Rosenthal
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