Agitating – Cover or shield for mixing chamber
Reexamination Certificate
2000-11-27
2003-12-30
Soohoo, Tony G. (Department: 1723)
Agitating
Cover or shield for mixing chamber
C366S192000
Reexamination Certificate
active
06669360
ABSTRACT:
The present invention relates to a device and a method for sealing a discharge aperture in the base of a container, preferably a rotary container of a preparation machine, with a sealing cover arranged on a pivoting shaft by means of a carrying arm.
Such sealing devices are known in principle, in particular for mixing machines with rotating parts. In general, however, the sealing cover is always rigidly connected to the carrying arm and the pivoting shaft. In such an arrangement the sealing cover then unavoidably carries out a circular motion around the pivoting shaft. With this construction, it is disadvantageous that introducing the sealing cover into the discharge aperture of the container base is only possible when there is a considerable clearance between the external diameter of the sealing cover and the internal diameter of the discharge aperture, so the horizontal movement component of the circular motion in the gap caused by the difference in diameter can be brought under control. Because of the gap, with this configuration, there is however the disadvantage of considerable leakage, so no liquid or fine-grained products can be processed in a container closed in this manner.
It has been attempted therefore, with the subject-matter described in DE 29 03 951, to counteract this difficulty in that the sealing device is provided with an elastic bearing. Rubber or plastics parts are described in this case as the elastic member. The elastic element is arranged centrally below the middle of the sealing cover and is surrounded on at least two sides by a bearing bracket. The effective direction or respectively the effective axis of the elastic element is therefore on the one hand perpendicular to the sealing cover and on the other hand it goes directly through the center point of the sealing cover. By means of this construction, it is possible to tip the sealing cover in a limited manner with respect to the carrying arm. In DE 29 03 951, in an advantageous manner, the first part of the sealing movement is carried out as previously by means of a normal circular motion, in which the carrying arm moves by means of the driven pivoting shaft in an arc of a circle. However, as soon as the sealing cover reaches the discharge aperture in the base of the container, and hits it, the return element comes into action and allows limited diversion of the sealing cover from the circular motion, so that it matches up with the discharge aperture, while the carrying arm holding the cover terminates the circular motion. The return element is consequently able to compensate for the difference between the direction of movement between the inside edge of the discharge aperture on the one hand and the outside edge of the sealing cover on the other hand.
This solution has been proven for simple applications, however it is unsuitable for applications using tightly closed containers such as, for example, vacuum or pressure containers. In addition, the return element is difficult to adjust and requires frequent re-adjustment.
In many applications the bases of preparation machines are protected by particularly wear-resistant facings. These can be, for example, compound steel, ceramics or basalt tiles. All these facings are, however, relatively thick, so that discharge apertures unavoidably arranged therein increase in depth. In order to close such deep discharge apertures, a very large deviation of the cover movement from the circular movement of the carrying arm is necessary. The cover must, on the other hand, be inserted in an approximately linear manner into the discharge aperture. The known sealing devices are not in general sufficiently capable of sealing such deep discharge apertures satisfactorily tightly.
The object of the present invention is therefore to provide a sealing device with which, in spite of simple construction and advantageous insertion characteristics, a reliable closure with good sealing is provided, which allows long servicing intervals, and also ensures pressure or vacuum sealing capability during long-term use.
With respect to the device, this object is solved in that a means for regulating or respectively for controlling the position of the sealing cover in relation to the discharge aperture is provided so that the lifting movement of the cover when entering the discharge aperture is substantially linear, that is to say translatory, and can take place substantially parallel to the central axis of the sealing cover.
This means that, before or at the start of entry into the discharge aperture of the container, optionally also by means of engaging with the edge of the aperture, the cover tips over into an orientation substantially parallel to the plane of said edge of the aperture, and is moved in this orientation into its final sealing position. The regulating or respectively the controlling of the cover tipping can take place both actively or passively.
One possibility for implementing such regulating, or respectively controlling, is, for example, in that the sealing cover is connected via a return element to the carrying. arm, so that the sealing cover can be tipped with respect to the carrying arm about at least one tipping axis. In this case, the tipping axis is advantageously arranged parallel to the pivoting shaft. This return element allows a defined tipping movement of the sealing cover with respect to the carrying arm, about the tipping axis. The tipping movement can be caused both by active controlling, for example, using a drive means, or by passive controlling, for example, by the sealing cover coming into engagement with the inside edge of the discharge aperture.
A preferred embodiment provides that the return element is arranged such that its effective axis lies outside the plane spanned by the tipping axis and a connecting line between the tipping axis and the center point of the sealing cover.
The effective axis can run, for example, parallel to the plane described. An arrangement is particularly preferably, however, in which the effective axis of the plane described forms an angle of at least 10°, preferably at least 20°, and particularly preferably 30°. According to the type of application, a larger angle between the effective axis and the plane described can also be advantageous.
The return element is arranged in an alternative embodiment such that a connecting line between the effective points of application of the return element to a closest, parallel line passing through the tipping axis, has a clear distance which is preferably more than 10% of the radius of the cover. When the tipping axis intersects the axis of the sealing cover, the return element is preferably arranged asymmetrically to the axis of the sealing cover. In this way it is possible to tip over the sealing cover much further with respect to the carrying arm. The elongation excursion or respectively the spring excursion of the return element is greater, the further the return element is arranged away from the axis of the sealing cover.
In particular for larger degrees of elongation of the preferably elastic return element, and/or with stronger forces operating on the return element, it is advantageous to make the return element from one or more springs. Advantageously, compression springs or combinations of compression and tension springs are used.
Alternatively to this, the return element can also be a hydraulic or a pneumatic cylinder. Additionally, an embodiment is particularly preferred in which the return force of the return element is adjustable. The sealing device can in this way be easily adapted to the properties of the discharge aperture such as, for example, the depth of the discharge aperture, or to the counter forces existing. The alteration of the depth of the discharge aperture or alterations in the elastic member caused by aging can be compensated for by re-adjustment of the return force of the elastic member.
Where the return element is composed of one or more springs, a tension screw can be provided which controls the pre-tensioning of the springs. In the case of pneumatic o
Adelmann Dieter
Eirich Paul
Dinsmore & Shohl LLP
Maschinenfabrik Gustav Eirich
Soohoo Tony G.
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