EP2100121A1

EP2100121A1 - Apparatus for early fault recognition on machines and/or components thereof

Info

Publication number: EP2100121A1
Application number: EP07856949A
Authority: EP
Inventors: Eberhard Schlücker; Piotr Reichel-Lesnianski; Stefan Blendinger
Original assignee: Friedrich Alexander Univeritaet Erlangen Nuernberg FAU
Current assignee: Friedrich Alexander Univeritaet Erlangen Nuernberg FAU
Priority date: 2006-12-20
Filing date: 2007-12-19
Publication date: 2009-09-16
Also published as: DE102006060382A1; WO2008074501A1

Abstract

In an apparatus for early recognition of faults in technical or physical parameters of machines or appliances and/or components thereof, the design is such that the apparatus used for early recognition of faults is at least one static or, in particular, dynamic seal (1) provided for the machine or the component thereof, that the seal (1) is provided with a measuring device (4) for detecting the technical or physical state of the seal (1) itself or a change of state thereof, that the measuring device (4) has at least one sensor element (2) for detecting the change of state of the seal (1) which is brought about by wear or a fault on the seal (1) itself, on the component (5) which is to be sealed by the seal (1) and/or on the overall machine, and that the sensor element (2) detects the resilience of the seal or the resultant deformation thereof and/or the expansion or compression of the seal (1) and/or a pressure-induced alteration in the seal (1) and/or oscillations or vibrations in the machine or in a component (5, 6) thereof.

Description

Device for early fault detection on machines and / or their components

The invention relates to a device for the early detection of disturbances of technical or physical parameters of machines or devices and / or their components according to the preamble of claim 1.

In the case of machines or devices and / or their components, it is highly desirable for technical as well as economic reasons to detect changes or even disturbances of technical or physical parameters immediately after their occurrence or, if possible, not to occur at all ie So in the best sense to carry out an early detection of such threatening disturbances or changes in state.

To achieve this goal, numerous devices of quite different nature are already known. However, these are common to all, that they only concentrate on very specific manifestations of a disturbance, for example acoustic, optical or the like. This has the consequence that they are not applicable to other types of disturbance or change of state of the machine or the machine component, because this is not suitable or intended. The invention is therefore based on the object to eliminate the disadvantages described to provide a device for the early detection of disturbances technical or physical parameters of machines or devices and / or their components, by means of which it is possible on the basis of a single machine component, all relevant disorders to detect the machine or a component thereof.

The features of the invention to solve this problem emerge from claim 1. Advantageous embodiments thereof are described in the further claims.

The invention is based on the essential idea of using at least one static or, in particular, dynamic seal provided as a device for the early detection of disturbances, which is provided with a measuring device for detecting the technical or physical state of the seal itself or of the State change is provided. In this case, the measuring device has at least one sensor element for detecting the condition of the seal caused by wear or disturbance on the seal itself, on the component to be sealed by the seal and / or on the entire machine; This sensor element according to the invention is designed such that it is the resilience of the seal or the deformation caused thereby and / or the expansion or compression of the seal and / or caused by pressure change of the seal and / or vibrations or vibrations of the machine or a component thereof detected.

In an embodiment of the invention, the sensor element may be a strain gauge, a piezo film or a piezoelectric element, a capacitive evaluable or an inductively evaluable element.

Instead, it is also possible according to the invention for the sensor element to consist of the material of the gasket itself, which is selected such that it can be used Detecting strain or compression of the gasket via changes in electrical conductivity or charge allowed.

Advantageously, the sensor element may be attached to or applied to the surface of the seal and extend over at least a portion of the seal surface.

In this case, it is possible for the sensor element to be vapor-deposited, printed or glued onto the sealing surface.

It is within the scope of the invention that the sensor element is instead integrated in the seal.

Regardless of the manner of applying or attaching the sensor element to or in the seal, it is possible that this extends transversely to the seal axis and / or in the direction of the seal axis.

The invention provides many possible applications and advantages, of which only the following are described by way of example:

1. By the invention it is possible to detect disturbances on the seal itself in a simple manner as early as possible. Here are seals, in particular dynamic seals, as known, for sealing under static conditions or under rotary or translational movements. The seal is often the technical properties, such as sliding speed, surface quality, dimensions, tolerances, etc. of the surrounding technical components, such as shafts or pistons exposed. For example, if the shaft or piston is worn, the seal must compensate for this loss of material by its compliance, or if, for example, the tread of the shaft or seal becomes rough, this manifests itself at the seal by appropriate vibration. The invention therefore makes use of this technical phenomenon in an advantageous manner, namely to the effect that in many cases seals make it possible to detect which technical changes in state the assigned sealing point is experiencing.

This is, as already mentioned, the invention by the relevant seal by incorporation of metrological elements, such as strain gauges, piezo film, vapor-deposited on the seal, printed or glued sensor elements or capacitively or inductively evaluable sensor elements capable of, interference, which occur on their own or in the sealing area, can be detected early.

In this case, as possible damages that can be detected in this way, the following are listed by way of example only:

a) Wear of the sealing lip: In this case, in order to ensure tightness, the seal must compensate for wear due to resilience. This changes her shape. This change in shape can be registered by the inventively provided on or in the seal measuring device and also quantified;

b) wear on the component to be sealed by the seal, for example shaft or piston: This changes the roughness of the surface of the relevant component, which also changes the signal resulting from the changed seal friction;

c) Lack of lubrication: the signal resulting from the changing frictional effects also changes. This can be done depending on the type of seal and a deformation of the seal, which also serves as an indication of dry running.

d) loss of fill level in the space to be sealed by the seal. 2. As already stated, seals, in particular dynamic seals, not only according to the invention can be used for detecting intrinsic disturbances, but within the scope of the invention also for the detection of disturbances to the surrounding sealing components or to the respective machines themselves. As is known Here seals are a frequently indispensable element in mechanical engineering, since they serve for sealing under static conditions or rotary or translational movements. The sealing material used and the shape of the seal are usually chosen so that the seal fulfills its sealing purpose by a certain flexibility. At the same time this also means that the seals are very intimately connected to the components of the machines, so that any vibration or vibration of the machine is transferred directly to the relevant seal.

Since now provided according to the invention, as a device for the early detection of disturbances at least one intended for the machine or its component, in particular dynamic, apply seal and this with a

Measuring device for detecting the technical or physical state of

To provide seal itself or its change in state, it is possible to detect the resilience of the seal by means of at least one corresponding sensor element of the measuring device. Thus, even at an extremely early stage disturbances in machines are immediately recognizable that express or are caused by vibrations or vibrations.

Only for the sake of example, a gear transmission should be mentioned at this point, which is usually subject to tooth wear. This creates a game magnification that leads to blows between the teeth. These shocks are transmitted via the shaft to the shaft seal and can be registered or detected there in the sense of the invention.

3. Finally, it is also within the scope of the invention to use seals as pressure sensors or as fluid level indicator or as fluid level monitoring sensors. In this regard, it is well known that seals basically have the task of separating or keeping separate spaces with different chemical contents or physical parameters. This is usually done by installing gaskets made of materials that deviate from the surrounding materials. In addition, special seal shapes are often used to achieve optimum tightness.

The sealing effect is achieved in this case usually on the construction of a sealing pressure by means of a certain resilience of the seal. In many cases, this also serves to compensate for any wear on the seal or on the surrounding components. As a result, gaskets are key elements in most applications and are therefore essential because they form solid components in technical products.

According to the invention is now also provided in the field of application here with the appropriate measuring device

Seal used as a device for detecting the pressure prevailing on her and thus for fluid level display or for fluid level monitoring. These

Function is inventively fulfilled by taking place in the seal installation of at least one sensor element that can detect the deformation. This can be done by pouring the sensor element in plastic seals, by

Apply to the sealing surface etc.

Since the sealing effect is usually associated with a certain resilience of the seal, it can be assumed that this compliance is greater, the higher the pressure acting on the seal. The degree of compliance is thus taken according to the invention as a measure of the prevailing fluid pressure.

Just as an example, a gearbox is mentioned here. Here, each gear has a drive and an output shaft. The seal of at least one of the two shafts is flooded with lubricating oil. To ensure the transmission function, it is important not to let the level of fluid above the seal drop too far. Since the pressure acting on the seal according to the invention by means of this provided measuring device is detected, the seal also serves as a level gauge, so that a separate level measurement can be omitted. This represents a big economic advantage.

Also in the field of application at issue here, the measuring device of the seal provided according to the invention can have the following embodiments only for the sake of example:

a) attaching one or more strain gauges to the sealing surface, which are aligned according to the measured variable to be detected; b) applying piezofilms to the seal surface at appropriate locations; c) implanting piezoelectric elements into the seal; d) evaporating such structures onto the seal surface that are similar to a strain gauge; e) manufacture the entire gasket made of materials that recognize the

Strains or compressions via changes in electrical conductivity or

Allow charge; f) embodiment of the seal such that changes caused by pressure can be measured capacitively or inductively; g) Installation of sensor elements for pressure measurement in stuffing box packing etc.

These embodiments include the following types of seals:

a) seals for rotating sealing tasks, such as lip rings. Proper placement and alignment can separate the pressure signal from other influences. b) seals for oscillating sealing tasks, such as V-rings, roof boots, step seals, lip rings, stuffing box packings; c) o-rings; d) specialist gaskets for flanges, containers, etc. e) special types of gaskets, such as those used, for example, in hygiene technology, high-pressure technology, etc. The invention will be explained in more detail below in the form of some embodiments with reference to the drawing. Hereby show:

Fig. 1 shows schematically a sealing ring with a applied to the surface

Strain gauges as a sensor element;

2a is a schematic side view of a seal with a on the

Dichtungsoberfäche mounted sensor element having a relatively small sensor surface;

2b a sensor element integrated into the seal and FIG

Fig. 2c shows a sensor element attached to the surface of the gasket which propagates over the entire sealing surface;

3 is a schematic side view of a seal with sensor elements extending in different directions;

Fig. 4 is a seal with it transversely to the sealing axis over the entire

Seal surface extending sensor element;

Fig. 5a shows schematically a inventively designed shaft seal in

Normal state and

Fig. 5b detected in a measuring device according to the invention

State of a certain compliance;

6 is a perspective view of a sealing ring with sensor elements which are arranged in different directions; 7 schematically shows a sealing ring with a sensor element which extends over the entire circumference of the sealing ring;

Fig. 8 shows schematically in the diagram the time-recorded strain signal of the inventively designed seal with short-term static load and

9 is a schematic diagram of the strain gauge of a seal designed according to the invention during the transition from a lubricated to a dry piston surface.

As can be seen from Fig. 1, the illustrated seal 1, which has the shape of a sealing ring, serves as a measuring device for detecting the pressure exerted on it and thus the resulting yielding. For this purpose, the sealing ring 1 is provided on its outer circumference with a sensor element in the form of a strain gauge, so that thereby all state changes of the gasket 1 itself and thus also of the surrounding components can be detected.

In Fig. 2a to c is shown schematically in detail, in which way the sensor element 2 may be connected to the seal 1. Thus, in the exemplary embodiment according to FIG. 2 a, the sensor element 2 is applied to the surface of the seal 1 by suitable manufacturing measures (vapor deposition, galvanic application, gluing, printing) and only extends over a relatively small sealing surface.

In contrast, the sensor element 2 is integrated in the embodiment of FIG. 2b in the seal 1, while it is again attached to the surface of the seal 1 in the embodiment of FIG. 2c, but extends over the entire circumference of the seal 1. The nature of the orientation of the respective sensor element 2 in relation to the seal 1 is shown in FIGS. 3 and 4 for the sake of example. It can be seen in the upper part of FIG. 3 that the sensor element 2 extends in the direction of the sealing axis 3, while in the lower part of FIG. 3 it extends transversely to the sealing axis 3. In both cases, however, the sensor element 2 is provided with a corresponding measuring device 4 for detecting the relevant measurement signals of the sensor element 2.

From Fig. 4 is a modified embodiment of the sensor element 2 can be seen; this extends over the entire circumference of the seal 1, wherein it extends transversely to the sealing axis 3.

In the embodiment of FIG. 5, the seal 1 is shown as a shaft seal, which seals in the usual way a rotating shaft 5 relative to a stationary component 6. Now, when the normally-located seal 1 according to FIG. 5a is subjected to changed sealing conditions (increased pressure, wear, etc.), it is deflected, i. indicates in a corresponding manner, as indicated in Fig. 5b. Here are then both sides of the seal 1 attached sensor elements 2, for example in the form of strain gauges, able to detect such compliance immediately and display it in a suitable manner.

In Fig. 6 a sealing ring 1 is shown in perspective, in which for the sake of example, the sensor element 2 shown on the left, which is applied to the surface of the seal 1, extends transversely to the sealing axis 3, while the right in Fig. 6 shown sensor element 2 in Direction of the sealing axis 3 runs. This makes it possible due to the provided two self-sufficient sensor elements 2, - for example in the form of strain gauges - both tilting of the seal 1 (by means of extending in the axial direction of the right sensor element 2) and diameter changes of the seal 1 (by means of running in the direction of the left sensor element 2) to register. In contrast, Fig. 7 shows a connected to a measuring device sensor element 2, which extends on the surface of the seal 1, but over the entire seal circumference - transverse to the seal axis 3 - extends.

From FIG. 8, the strain signal of a seal 1 provided with strain gauges as the sensor element 2 can be seen in the diagram, wherein the axial stress V measured at the measuring device 4 is plotted over the time s and clearly the short-term static load can be recognized, which results if the seal 1 serves as a pressure gauge or as a fluid level gauge.

Similarly, the strain gauge of the seal in the transition from a lubricated to a dry piston surface can be seen from Fig. 9 in the diagram.

With regard to features not explained in detail above, reference is expressly made to the drawing and to the claims, moreover.

Claims

claims

1. A device for the early detection of disturbances of technical or physical parameters of machines or devices and / or their components, characterized in that as a device for the early detection of disturbances at least one provided for the machine or its component, static or dynamic particular seal (1) serves,

- That the seal (1) is provided with a measuring device (4) for detecting the technical or physical state of the seal (1) itself or its change in state,

- That the measuring device (4) at least one sensor element (2) for detecting caused by wear or failure of the seal (1) itself, on the by the seal (1) to be sealed component (5) and / or on the entire machine Has state change of the seal (1) and

- That the sensor element (2) the resilience of the seal or the deformation caused thereby and / or the expansion or compression of the seal (1) and / or caused by pressure change of the seal (1) and / or vibrations or vibrations the machine or a component (5, 6) thereof detected.

2. Device according to claim 1, characterized in that the sensor element (2) is a strain gauge (DMS).

3. Device according to claim 1, characterized in that the sensor element (2) is a piezo film or a piezoelectric element.

4. Apparatus according to claim 1, characterized in that the sensor element (2) is a capacitive evaluable element.

5. The device according to claim 1, characterized in that the sensor element (2) is an inductively evaluable element.

6. The device according to claim 1, characterized in that the sensor element (2) consists of the material of the seal (1) itself, which is selected such that it is the detection of strains or compressions of the seal (1) via changes in electrical conductivity or charge allowed.

7. Device according to one of claims 1 to 5, characterized in that the sensor element (2) on the surface of the seal (1) attached or mounted thereon and extends at least over part of the sealing surface.

8. The device according to claim 7, characterized in that the sensor element (2) is vapor-deposited on the sealing surface, printed or glued.

9. Device according to one of claims 1 to 5, characterized in that the sensor element (2) in the seal (1) is integrated.

10. Device according to one of the preceding claims, characterized in that extending the sensor element (2) transversely to the sealing axis (3) and / or extending in the direction of the sealing axis (3).