Valves and valve actuation – With non-fluid retarder
Reexamination Certificate
2000-07-10
2001-11-20
Fox, John (Department: 3753)
Valves and valve actuation
With non-fluid retarder
Reexamination Certificate
active
06318702
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a shutoff device having a shutoff body which is movable by a drive between abutments.
2. Description of the Prior Art
Shutoff devices of that kind, including shutoff valves, which in particular are electromagnetically drivable, often give rise to noises in the opening and closing phases, such noises in many cases also being referred to as “valve chatter”. Although the shutoff bodies, including valve plates or disks, often comprise a rubber-elastic material or are provided with a damping coating, it is often not possible to avoid such noises; they are passed in particular along the lines or conduits which they open or close, to locations at which such noises are perceived as being extremely troublesome and disturbing.
SUMMARY OF THE INVENTION
The object of the present invention, using simple means, is to avoid or at least substantially alleviate the production of noise upon actuation of such shutoff devices.
The invention provides a shutoff device having a shutoff body which is movable by a drive between abutments, and a friction brake which is intermittently movable with the shutoff body under the control of at least one control body with which the friction brake makes contact when the shutoff body still has to travel a respective friction distance to each abutment, wherein the friction brake rubs along a friction surface during the movement of the shutoff body along the friction distance.
Preferred configurations thereof are claimed in the dependent claims. Particularly preferred configurations are described with reference to the specific description.
The invention provides that a friction brake is movable with the shutoff body, the friction brake braking the movement of the shutoff body somewhat shortly before encountering the corresponding abutment, so that the shutoff body hits the abutment only with a reduced amount of force. The friction brake is therefore intended to come into operation in each case a friction distance before the moment in time at which the shutoff body reaches the abutment in question. The function of the friction brake is to rub along a friction surface as the shutoff body moves along the friction distance.
The friction surface can be formed for example by the stem of the shutoff body, which connects the latter to the drive. The friction surface can also be formed by the inside wall of a housing, with a drive body for the shutoff body being movable along the inside wall. The production of noise is determined by the particular dimensioning of the friction force between the friction brake and the friction surface, that is to say in particular by the material of the friction brake and surface nature of the friction surface. In many cases it is recommended that the friction surface be embodied by means of a thin coating on the unit in question.
The control body may be connected to the abutment for the shutoff body, in the opened position thereof. In another configuration according to the invention, the control body is connected to the shutoff body itself, in that case, the recommendation is for the drive body for the shutoff body to be provided with surfaces which act as control bodies.
In the simplest structure the friction brake can be in the form of a ring. Depending on the structural conditions involved however it is also possible to recommend using a friction brake which has two abutment flanges, in particular at the ends thereof.
The use of thermoplastic homopolymers, in particular polyoxymethylene (POM) is recommended as the material for the friction brake.
It is recommended that the drive has an electromagnetically operative armature as the electromagnetically actuable drive body. A spring may apply a counteracting force to the drive body so that, in the absence of actuation of the drive, the spring urges the shutoff body into the closed position against for example the valve seat, while to lift off and open the shutoff body, the electrical coil of the electromagnetic drive is energized so that the electromagnetic field of the coil moves the armature and at the same time pulls the shutoff body out of the closed into an opened position. The extent of the stroke movement involved in lifting of the shutoff body off the valve seat is limited by another abutment. In this embodiment, the closing force for the shutoff body is produced by the spring and the opening force is produced by the electromagnetic drive.
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Hettel Alfred
Obermann Axel
Fox John
Proskauer Rose LLP
Siemens Building Technologies AG
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