GB2365530A

GB2365530A - Vibration measurement device with temperature detector

Info

Publication number: GB2365530A
Application number: GB0105282A
Authority: GB
Inventors: Heinrich Lysen
Original assignee: Prueftechnik Dieter Busch AG
Current assignee: Prueftechnik Dieter Busch AG
Priority date: 2000-08-01
Filing date: 2000-08-01
Publication date: 2002-02-20
Anticipated expiration: 2020-08-01
Also published as: GB2365530B; GB2365527B; GB2365527A; GB0018878D0; GB0105282D0

Abstract

A vibration measurement device (1010) includes a pyroelectric temperature sensor (1024, 1034) for detecting surface temperature of an article (1014) contacted by a probe (1022) of the device and an acceleration sensor (1028, 1030, 1032) for detecting vibration of the article and also for reading the code of a code carrier attached to the article to derive information concerning the article or another aspect of the detecting processes.

Description

<Desc/Clms Page number 1> UNIVERSAL VIBRATION MEASUREMENT DEVICE The present invention relates to vibration measurement devices.

A versatile vibration measurement device has been marketed for some time by the company Prueftechnik AG under the name "Vibrotip." With this device, it is possible to record both solid-borne noise quantities or vibration quantities of interest, and with a suitable ication sensor, it is also able to receive identification data. In addition, it is possible. to i 'dentif measure the temperature of objects of interest with a temperature sensor which is attached separately to the indicated device.

Although the indicated device can be classified as a practical measurement means for monitoring and maintenance of a host of machine types, it has the defect that there are separate sensors for the various measurement tasks (specifically vibration diagnostics, identification of measurement sites, temperature measurement), and this increases the costs of production of the device. In addition, its operation is more difficult than if there were only a single sensor for all of these various measurement tasks.

Flat code carriers have been known for a long time, the coding elements conventi onally being made as parallel black strips with two different widths wl#ch are pninted on a flat code carrier, for example, apaper orplastic film label whichhas been cemented on, and thus they code information 'in digital form. To read one such code carrier, conventionally, a laser diode reader is used which decodes them'formation based on the laser light intensity backscattered by the strip and corresponding evaluation electronlics. These systems are known as bar code scanners.

Published European Patent Application No. 0 194 333 and U.S. Patent No. 4,885,707, for example, -disclose systems for vibration acquisition from machines with rotating elements, at the measurement site on the machine the above described conventional bar code carrier being attached which is read and decoded before the actual vibration acquisition measurement process by a corresponding optical scanner in order to obtain the specific Mifon-nation or data which is necessary for the subsequent vibration measurement and its evaluation. Subsequent vibration measurement takes place by means of a conventional piezosensor. According to U.S. Patent No. 4,885,707, there are two separate measurement heads for decoding and vibration acquisition, while according to published European Patent Application EP-A-0 194 333, the different sensors which are needed for the two measurements can be integrated into a pin-like housing which is connected via connecting cables to the actual evaluation unit. With this device, the operator can apply the reading element with a tip like a pin to the corresponding measurement point for vibration acquisition after the assigned bar code has been acquired beforehand by the reading element having been moved with its tip at a certain distance over the successively arranged strips of the bar code, Published German Patent Application DE 44 20 562 Al discloses an optical sy stem which, on the one hand, can read the bar code which is attached to a machine which comprises a rotating body, and on the other hand, can determine the rpm of the rotating body by means of optical marking attached to the body.

Published European Patent Application EP 0 211212 A2 discloses a vibration acquisition system in which a data transmission part is screwed into each measurement point which, on the one hand, provides for coupling to the vibration sensormi the measurement head, and on the other hand, provides machine-specific or measurement pomit-specific information in the, form of optical, magnetic or mechanical identifiers; this information is acquired by a corresponding

decoding sensor in the measurement head. The identifiers are provided here in the form of parallel circumferential rings.

In published European Patent Application EP 0 762 131 A2 a vibration measurement head is disclosed which is placed manually in a V-shaped recess on the surface of the object to be measured, the tip of the vibration measurement bead being convexly rounded and recording the vibration of the machine surface and transmitting it via a corresponding coupling element to a piezosensor which is coupled to the corresponding opposing masses.

The defect in the known flat code carriers is that they can only be optically read, and furthermore, generally are not suited for use in rough environments, for example, at high temperature and the like. The primary object of the present invention is to solve the aforementioned problem of the prior art and to provide a universal vibration measurement device which has a single sensor which is designed to be able to perform at least two, or ideally all, of the indicated measurement tasks.

This object is achieved in accordance with the present invention by the means described herein below.

The universal vibration measurement device of the present invention has a sensor with which not only acoustic quantities, especially solid-borne noise, can be measured, but which is also able to read pertinent and suitable code carriers so that identification of different measurement points is possible. In one special embodiment, it is also possible to use the sensor as a temperature sensor at the same time.

The inventive solution calls for an essentially conventional vibration sensor to be modified such that it is possible to read code carriers with geometrical-mecbanical structures. Compared to optical code carriers, the reading ofthese code carriers has the advantage that faulty readings due to-dirt on the.code-carrier-are-less frequent. For this purpose, in a first embodiment of the invention, a sound conduction element which is present in a conventional vibration sensor is used as a magnetic flux generator and flux concentrating piece for magnetic quantities so that, with it, a bit pattern in the form of recesses of various sizes in a ferromagnetic material can be detected. The pertinent code carrier according to the invention should, therefore, be made of a

piece of ferromagnetic material into which recesses of various sizes have been made at suitable points which can be read by the indicated combination sensor and can be delivered to decoding. Thus, the identification of a special measurement point, a machine or another article is enabled. In a second embodiment of the invention, a different comb miation of the code reader and code carrier is proposed. The code reader can be a modified vibration sensor which in its regular function is suitable for acquisition of solid-bome sound, and the code carrier can be mechanical surface structures in any materials which are to be scanned by the code reader. In another version of the invention, the.last mentioned embodiment is expanded such that temperature can be measured with the same sensor in addition. To do this, the fact is used that piezoelectrically operating vibration sensors generally show apyroelectric effect. According to the 'invention, this pyroelectric effect is used with the vibration sensor to also measure temperature of an area which is essentially limited to a small-volume, roughly point area.

According to the aforementioned embodiment of the invention it is advantageous that the coding elements of the code carrier are made very simply and durably, and that they can be easily and reliably read. In particular, the coding elements need not be optically read, although this is possible.

Preferably, the openings are made circular as holes with a diameter which codes the information, preferably for digital coding two different diameters being provided. This enables the code carrier to be easily produced.

For comfortable readability, the openings are preferably arranged in a row one behind another, and the code carriers can have a guide for the reading element in order to guide the reading element along the row of opemings. Here, the guide is made preferably as a V-shaped trough with the openings formed on its base.

For easy readability, the code carrier can be made of ferromapetic material. But, code carriers of electrically conductive, nonferromagnetic material are also possible, by which likewise magnetic or inductive code acquisition is possible. In particular, the code carrier can be made of stainless steel or stainless chrorm'urn/nickel-containing alloy.

The code carrier can be cemented to an article to be coded by means of an adhesive surface, and preferably, has an additional opening by which a vibration probe can be coupled to the article to be coded.

Preferably, the code carrier is made such that it withstands temperatures up to 350'C and is watelproof and water vapor-proof.

For the reading element, the sensor is preferably made for magnetic scanning, and it can be a Hall probe, an induction coil, an eddy current sensor or an inductive proximity sensor. Preferably, the reading element integrates a vibration sensor for acquiring the vibrations of the article to be coded which preferably comprises a piezoele-ment which can be coupled via a rigid contact element to the article which is to be scanned and coded.

The front end of the reading element can be made elastic and shaped such that it is guided in the guide of the code carrier. Here, it can be formed by a convexly rounded molding which has an opening for tight passage of the tip of the contact element and which is shaped such that the contact element does not extend into the coding openings when the reading element is placed in the guide. Preferably, the contact element is guided through the magnetic sensor which is embedded in the molding.

The reading element can be made telescoping so that the vibration sensor can be pushed in the lengthwise direction of the reading element relative to the decoding sensor. Preferably, the reading element is suited for scanning of surfaces with temperatures up to 350T.

In a second preferred embodiment of the universal vibration measurement device, the simple configuration is advantageous. The vibration measurement device is preferably made at the same time for acquiring the temperature of the surface of the article to b#,- coded, a temperature sensor being coupled to a pointed pin or probe in order to measure the temperature at the probe. The evaluation unit is thus preferably made such that by means of a mathematical model it determines the temperature of the surface to be measured from the time behavior of the temperature acquired on the probe after the probe is attached. This temperature determination process allows greater accuracy than temperature measurement which is based only on the attained steady-state maximum value of the probe temperature.

Preferably, the acceleration sensor is made as a piezoelement and is used at the same time as a heat flow sensor in order to increase the accuracy of temperature measurement. Furthermore, preferably, the vibration measurement device is made at the same time for acquiring the vibrations of the surface of the article to be coded so that it can be used, for example, for checking steam traps for leaks, the acceleration sensor also being used to acquire vibrations of the surface of the article to be coded.

Since this multiple function of the acceleration or vibration sensor, i.e., as an acceleration sensor in the scanning of the code carrier, as a heat flow sensor in the temperature measurement and as a vibration sensor in the acquisition of vibrations of the surface of the article to be coded, takes place in different frequency ranges and still good sensitivity is to be achieved as much as possible in each frequency range, preferably, there are two seismic masses, coupling of the one seismic mass to the vibration or acceleration sensor, i.e., the single piezoelectric element, being more strongly dependent on frequency than the coupling of the other seismic mass to the sensor. Here, the coupling of the seismic mass which is coupled more strongly dependent on temperature is much stronger at low fTequencies than at high frequencies in Order to impart to the entire system both resonance at low frequencies and also resonance at high frequencies. Preferably, the two seismic masses and the frequency response of the coupling to the sensor are chosen su,,`#i that the first resonant frequency of the entire system is in the range below I kHz and the secc- resonant frequency of the entire system is in the ultrasonic range.

These and ftiftheT objects, features and advantages of the present invention will become apparent from the following description when taken in connection with the accompanying drawings which, for purposes of illustration only, show several embodiments in accordance with the present invention. Figure I shows one aspect of the code carrier according to a first embodiment of the invention; Figure 2 shows a section along line H-Il in Figure 1, in addition a read ng devi I ice according to the first embodiment of the invention being shown which is placed on the code carrier to read the code; Figure 3 is a view similar to that of Fig. 2 showing additional means for cooling of the sensors; Figure 4 is a schematic perspective view--of a code carrier *in accordance with a second embodiment of the invention; Figure 5 is a graph of the vertical path which is traversed by the probe in scanning of the code carrier of Figure 4 as a function of the lateral location;

Figure 6 is a view similar to Figure 4, showing a second embodiment of a code carrier in accordance with the invention; Figure 7 is a graph similar to that of Figure 5, but for the embodiment of Figure 6; Figure 8 is a schematic view of a reading device in accordance with the invention for scanning of the code carrier from Figures 4 & 6; and Figure 9 is a plot of the frequency response of the charge of the piezoelement of the reading device from Figure 8. As shown in Figure 1, a flat code carrier 10 is cemented onto a surface 12 of an article to be coded by means of an adhesive 14 (Fig. 2) with silicone rubber. However, the code carrier 10 can also be attached in some other way, for example, by riveting or using other adhesives.. The article to be coded is preferably part of a machine or system, for example, a steam trap, valves, a feed or drain, as well as machinery parts of spherulitic graphite iron or gray cast iron with vibrations which are to be checked or measured on or near the coded site. The code carrier 10 is designed to make available article-specific or measurement point-specific information which is necessary for a measurement or test process. The code carrier 10 comprises essentially a plate 16 the rear surface of which is glued by adhesive 14 to the surface 12 and which is made of a ferromagnetic or nonferromagnetic material, preferably, of stainless steel or a suitable stainless chromium/nickel-containing alloy.

It must be considered in the selection of the plate material that the code carrier 10 should be able to withstand temperatures up to 3 50'C and should be waterproof and water vapor-proof. For ferromagnetic material, thus a sufficiently high Curie point must be provided. If a nonferromagnetic material is chosen, it should be conductive enough to enable magnetic or inductive reading of the code carrier 10. Its conductivity should, if possible, be relatively temperature-stable over the temperature range under consideration, as is the case, for example, for constantan and the like. The information to be coded is coded digitally 'in the form of holes 18 which are arranged in a row, with holes of two different diameters, i.e., the information is represented by the diameter of the corresponding hole 18. In order to facilitate manual reading of the code carrier 10 by means of a corresponding pin-like reading element 20 which is explained below, the plate 16 is provided with a slightly V-shaped (prismatic) guide groove 22

with holes 18 made in its base. Furthermore, in the guide groove 22, there are additional openings 24, 25 by means of which a vibration probe 26 of the reading element can be coupled to the surface 12 of the article to be checked.

The reading element 20 is generally made pin-like for better manual handling and comprises essentially a decoding sensor 28 for reading of the code carrier 10 and a vibration sensor 26 for acquisition of the vibrations of the article .12 to be checked. The reading element or reading pin 20 can furthermore contain an evaluation unit (shown only in the schematic of Fig, 8) forprocessing of the-signals which have been delivered by the decoding sensor 28 and decoding the acquired information, or such an evaluation unit can be provided in a control unit or a base unit (not shown) instead. Generally, the reading pin 20 is connected via flexible electric connections to such a base unit which is provided anyway for evaluation of the signals of the vibration sensor 26. If the evaluation unit for the signals of the decoding sensor 28 is located outside the reading pin 20, the reading pin 20 is preferably connected via at least two cable pairs to the base unit. Power supply of the reading pin 20 is not required in general, and if necessary, can be provided by integrated batteries (not shown).

The decoding sensor 28 in the embodiment shown in Figure 2 is made as an inductive sensor with a cup-type core 30 and an induction coil 32 and is located near the front end of the housing 34 of the reading pin 20. The vibration sensor 28 is formed by a contact element 36 which is T-shaped in cross section and which is cormected to a piezoerystal 3 8 which, for its part, is provided with a seismic mass 40. The structure of the vibration sensor 26 corresponds essentially to the type known from published European Patent Application EP 0 762 131 A2 but other conventional vibration sensors can be used instead. On its upper end, the piezocrystal 38 is provided with an electrical contact 42 on which the vibration signal is tapped. The center of gravity of the seismic mass 40 is located underneath the piezoerystal 38. The downwardly extending rod-shaped part 44 of the contact element 36 is routed through the cup-type core 30 which surrounds the induction coil 32 and through the central opening of the coil 32, its rounded tip 46 extending through a rounded molding 48 which forms the tip of the reading pin 20. The molding is produced, preferably, from silicone rubber and in its convex form is chosen such that the tip 46 of the contact element 36, with the reading pin 20 seated in the V-shaped groove 22 of the code carnier 10, does not extend into the coding opemings 18 in orderto enable undisturbed

reading of the code carrier 10. The passage site of the tip 46 of the contact element 36 is sealed by the molding 48.

The magnetic sensor 28 is also embedded in the molding 48. Between the rod-shaped part 44 of the contact element 36 and the cup-type core 30 an air gap 50 is forined. In this embodiment, the vibration sensor 26 and the decoding sensor 28 are mounted so as to be essentially stationary relative to one another. But, the reading pin can also be made such that the decoding part is made separately and can be pushed back and forth in the manner of a telescope relative to the vibration probe.

Overall, the materials of the reading pin 20 should be chosen such that surfaces with temperatures up to roughly 350'C can be scarmed.

In a measurement or test process, first of all, the reading pin 20 with its molded end 48 is engage in the V-shaped guide groove 22 of the code carrier 10 at the correct end and is pulled manually over the row of code holes 1-8, the interaction of the guide groove 22 and the end 28 providing for corresponding guidance of the reading pin 20 on the code carrier 10. By means of the relative movement of the code carrier plate 16 with reference to the induction coil 32, the coil 32 "sees" a material with a spatially variable magnetic permeability based on the sequence of holes 18; this is expressed in a corresponding fluctuation, for example, of an induced voltage (or the effective inductance of the coil 32) as a function of the passage of one of the holes 18. The holes 18 with different diameters produce different changes of the induced voltage and can thus be distinguished from one another. Based on the voltage signals which are delivered by the coil 32, the evaluation unit can determine the sequence of openings 18 and thus decode the information which has been coded by the code carrier 10, by which this information can be considered in the subsequent vibration measurement process.

After completion of reading of the code carrier 10, the reading pin is placed on the additional opening 24 such that the tip 46 of the contact element 36 can be put through the opening 24 on the surface 12 of the article to be checked. But, for vibration acquisition, coupling to the code carrier 10 itself is also possible, if a correspondingly rigid coupling exists between the surface 12 and the code carrier 10. In this state, the vibrations of the surface 12 are acquired by the piezocrystal 38 via the contact element 36 and a corresponding voltage signal can be acquired by the evaluation unit.

As Figure 3 shows, to improve the thermal conditions in the sensor area of the reading element 20, there can optionally be a cooling body 60 or especially active cooling 62 with a Peltier element 64. The active cooling can generally keep the average temperature of the housing 34 at a roughly constant value by means of a temperature sensor (not shown). The Peltier element 64 used for active cooling can optionally be used at very cold ambient temperatures as active heating. In this way, the sensor elements 26, 28 are also operated at a roughly constant temperature; this is advantageous for the quality of the measurement results which are obtained.

In another embodiment of the invention, the sensor elements 26, 28 can be kept at a somewhat constant temperature by the coil 32 being heated by means of a direct current applied to it to a set temperature of roughly 50 to 80' C. This can easily be done by the direct current resistance of the coil being kept temperature-dependent and by the indicated current injection being changed until a stipulated resistance value is reached. This resistance value thus corresponds to a predefined set coil temperature. It goes without saying that above a certain ambient temperature for the coil 32, additional injection of current has no benefit, so that in this case current injection does not occur.

Figure 8 schematically shows ameasuring instrument 1010 formeasuring thetemperature and vibrations of a surface 1012 of a measurement object 1014 and for reading the height profile ofacodecarrier. The measuning instrument 1010 comprises apin-like measurement head 1016 which can be manually handled and an evaluation unit 1020 which is connected to it via flexible elastic cable 1018. The measurement head 1016 comprises a probe 1022 of rigid material with good thermal conductivity, a temperature sensor 1024 which is thermally coupled to the probe 1022, a plezoelement 1026 which is rigidly connected to the back end of the probe 1022, a first seismic mass 1028 which is connected to the piezoelement 1026, a second seismic mass 1032 which is elastically connected via an elastic coupling element 1030 to the first seismic mass 1028, and an auxiliary temperature sensor 1034 which is thermally connected to the second seismic mass 1032. Another temperature sensor 1036 is connected to the evaluation unit 1020 in order to acquire the ambient air temperature. The temperature sensors 1024, 1034 and 1036 are preferably made as semiconductor components.

The surface 1012 of the measurement object 1014 to be measured is provided with a punchmark 1038 inwhichthepTobe 1022 is manually placed in order to acquire the temperature and the vibrations on the surface 1012.

The first seismic mass 1028 which is rigidly coupled to the piezoelement 1026 is much smaller than the second seismic mass 1032 which is elastically connected to the first seismic mass 1028 by means of the coupling element 1030. Coupling of the first seismic mass 1028 to the piezoelement 1026 is essentially independent of frequency, while coupling of the second seismic mass via the elastic element 1030 which can be made, for example, as a circuit board is much more dramatically frequency-dependent, the coupling of the second seismic mass 1032 to the first seismic mass 1028, and thus to the piezoelement 1026, at low frequencies being much stronger than at high frequencies. The purpose of this arrangement is to create a vibration measurement system by means of the probe 1012, the piezoelement 1026 and the two seismic masses 1028 and 1030, which system has a first resonant frequency at low frequencies and a second resonant frequency at high -frequencies and thus is suitable for sensitive measurements in two separate frequency ranges.

Figure 9 is a sample schematic plot of the frequency response of the charge on the piezoelement 1026, i.e., essentially of the voltage signal of the piezoelement 1026, essentially three firequency ranges A, B and C being distinguishable. The first resonant frequency is on the top end of the low frequency range A at roughly I kHz, the range A being important essentially for measurements of heat flow and code carrier scans and measurements for deterinining the instant at which the probe is placed on the surface 10 12 to be measured, as is explamied below. The middle frequency range B which adjoins the area A is not of interest at this point and is masked out. The middle frequency range B is adjoined by a high frequency range C, on the top end of which, in the area of roughly I MHz, a second resonance being located. The range C is used to measure the vibrations of the surface 1012 of the measurement object 1014. The measurement object 1014 is preferably a steam trap with vibration behavior which is measured by means of the measurment device in order to deten-nine leaks.

When the temperature is being measured after the probe 1022 is placed on the surface 1012, first only a weak temperature rise occurs. This delay arises essentially from the geometry of the probe 1022, the local arrangement of the temperature sensor 1024 at a certain distance Rom the attachment site of the probe 1022 and the heat capacities of the probe 1022,

the piezoelement 1026 and the seismic masses 1028 and 1032. After a dead time has passed, finally, an essentially linear rise of the temperature acquired by the temperature sensor 1024 occurs, and after an inflection point is passed, finally, becomes increasingly more flat and asymptotically approaches a steady-state final temperature.

The temperature of the surface 1012 to be measured is determined by means of a mathematical model from the time behavior of the temperature acquired by the temperature sensor 1024 after the probe 1012 is attached instead of from the steady-state maximum temperature of the temperature sensor 1024 and the probe 1022. In this way, greater accuracy of the temperature measurement can be achieved by the fact that certain parameters which influence the maximum steady-state temperature, such as the thermal resistance between the surface 1012 and the probe 1022, can be considered. Other such important parameters are the ambient air temperature, the heat dissipation fromtheprobe 1022 to the environment, the thermal resistance of the probe 1022, the geometry of the probe 1022, the geometrical arrangement of the temperature sensor 1024, the thermal capacity of the probe 1022 and the elements which are thermally coupled to it (here: the piezoelement 1026, the seismic masses 1028 and 1032 and the coupling element 1030) as well as the thermal resistance between the probe 1022 and the temperature sensor 1024.

The evaluation UrN't 1020 is made such that the parameters which have been taken into account in the mathematical model are first determined ill a learni'ng process on known surfaces with known temperatures and are then stored. The parameters are determined by matching the measured temperature behavior on the sensor 1024 by means of a suitable curve matching procedure, from which the corresponding values of the pa:rameters result. In particular, for example, the then-nal resistance which varies from measurement process to measurement process between the probe 1022 and the surface 1012 to be measured can be determined using the ascertained parameters from the behavior of the temperature increase acquired by the temperature sensor 1024 and then used in the temperature computation. In this way then, in the ideal case, in- contrast -to the surface temperature detem-#nation process- from the maximum steady-state temperature, the ascertained surface temperature does not. depend on the thermal resistance between the surface 10 12 to be measured arid the probe 1022. The ambient temperature can thus be taken into account by its being acquired by the temperature sensor 1026.

Furthermore, the piezoelement 1026 also acts as a heat flow sensor for acquiring the heat flow via the probe 1022 so that the acquired time behavior of the heat flow in the model can be considered. Here, the fact is used that the temperature difference between the two electrodes of the piezoelement 1026 which corresponds to a certain heat flow through the piezoelement 1026 can be acquired via a corresponding charge separation, and thus, via a corresponding control signal.

In the simplestprocess fordetermining the surface temperature, from the above described curve matching, the thermal resistance between the surface 1012 to be measured and the probe 1022 and the slope of the temperature rise of the probe 1022 acquired by the temperature sensor 1024 at the inflexion point is determined, this slope being assumed to be proportional to the difference between the temperature of the surface 1012 to be measured and the initial temperature of the probe 1022 and proportional to the heat exchange between the surface 1012 to be measured and the probe 1022 and the temperature of the surface 1012 is finally computed from this slope at the inflexion point.

The instant of attachment of the probe 1022 to the surface 1012 to be measured is acquired by the evaluation unit 1020 by the occurrence of a corresponding voltage signal on the piezoelement 1026.

Furthermore, the evaluation unit 1020 is provided with a function which allows decoding of a corresponding code carrier 1040 and 10140 as is shown, for example, in Figures 4 and 6. One such code carrier 1040 and 10140 is used to provide the evaluation unit 1020 with information regarding to the measurement object 1014 or the special measurement site 1038. The code carrier 1040 and 10140 is made such thatthe information is codedby a defined height level which can be acquired during scanning, i.e., the information is coded by the height profile of the code carrier 1040 and 10140.

In the first embodiment of the code carrier 1040 shown 'in Figure 4, there are a total of three different height levels, the information being coded in binary form. The code carrier 1040 comprises several -coding areas 1042, in which the actual information, i.e, a "zero" or a "one," is coded, which areas are arranged next to one another in a row and are each separated from one another by an intermediate area 1044. The code carrier is preferably produced by corresponding etching of a etching sheet.

Jn each coding area 1042 , nutially, there is a bar-shaped coding element 1046 with a surface level which is lower than the surface level of the intermediate areas 1044. In this example, a "zero" is assigned to each codig area 1042 with the existing coding element 1046. A "one" is coded in a coding area by breaking out the corresponding coding element 1046. The coding elements 1046, for this reason, have a free end which projects beyond the edge of the intermediate areas 1044 and scoring on the opposite end with which it is attached to the code carrier 1040. The coding of the code carrier 1040, i.e., breaking out the corresponding coding elements 1046 for producing a logic "one," takes place generally before the code carrier 3. 040 is attached near the intended measurement site for the measurement device 1010. The code carrier 1040 can then be cemented onto the surface 1012, or for example, it can be attached by means of a pocket in the vicinity of the. measurement point.

Before measurement of the temperature or vibration by the measurement device 1010, the information which has been coded in the code carrier 1040 is acquired by the measurement device 10 10 by the probe 1022 being placed on the corresponding end of the code carrier 1040 and then being moved manually transversely over the successive coding areas 1042. In this contact scanning process, the probe 1022 essentially follows the surface structure of the code carrier 1010, with the piezoelement 1026 acting in conjunction with the two seismic masses 1028, 1032 as an acceleration sensor and acquining the acceleration of the probe 1022 in the vertical direction. Since this measurement is taken in the low frequency range, the heavy seismic mass 1032 is coupled essentially stationarily to the light seismic mass 1028 and thus to the piezoelement 1026, so that the heavy seismic mass 1032 determines the resonant frequency and thus the sensitivity. The acceleration signal delivered by the piezoelement 1026 is integrated in the evaluation unit 1020, by which finally a path signal is obtained which images the surface structure, i.e., the height profile of the code carrier 1040, see Figure 5 where the vertical path signal is plotted over the lateral site.

Figure 5 shows that the evaluation unit 1040 acquires a total of three different height levels: a first level which corTesponds to the surface of the intem-lediate areas 1044 and which is used as a reference level N), a second level which is determined by the surface of the coding elements 1046 which have not been broken out and codes a logic "zero" (h), and a third level which is acquired by the probe 1022 in the coding areas 1042 in which the coding elements 1046 have been broken out (h2)I this third level coding a logic "one." The third level is determined C>

here by the width of the coding areas 1042 and the shape of the probe 1022, but in any case is lower than the level of the coding elements 1046. Depending on whether the evaluation unit 1020 acquires a level h, or a level h2, this is decoded as a logic "zero" or a logic "one." The intermediate areas 1044 with their level ho are used as separating elements or spacers between two lock levels. In this way, the acquisition of the height profile of the code carrier 1040 and its decoding, in contrast to the conventional bar code coding, in which the width of a black bar is decisive for whether a "zero" or a "one" is decoded, is independent of speed since the individual coding areas 1042 are distinguished not by their width, but by their height level which is acquired by the probe 1022. The piezoelement 1026 can perform a total of four different functions according to the description above: I . as a heat flow sensor in the measurement of the temperature of the surface 1012, . -2# as a vibration -sensor in measuring the vibrations of the surface 1012, 3. as an impact sensor for acquiring the instant at which the probe 1022 is seated on the surface 1012, and 4. as an acceleration sensor for contact scanning of a code carrier 1040 in which information is contained regarding themeasurement object 1014 orthe measurement site 1038. Figure 6 shows a second embodiment of a code carrier 10140 in accordance with the invention. In this embodiment, the code carrier 10140 differs from the above described embodiment of a code carrier 1040 as shown in Figure 4 mainly in that the intermediate areas 10144 between the coding areas 10142 have a surface level which is lower than that of the codingelementIO146 in the coding areas 10142. This arrangement is produced by the fact that it is not the coding elements which are etched proceeding from the original homogenous surface of the code carrier 10140, but the surfaces of the intermediate areas 10144. Furthermore, the coding elements 10 146 are rounded for easier scanning in the scanning direction or against it in the two edge areas, these rounded regions being labeled 10150 in Figure 6. As in the embodiment shown *in Figure,4, one end of the bar-shaped coding elements 10146 is connected by scoring to the base body of the code carrier 10140, while the other end projects freestanding somewhat beyond the free end of the intermediate areas 10 144 so that the coding eleme-rits 10 146 can be easily grasped and broken out. Also in the embodiment shown in Figure 6, a coding

element 10146 which has not been broken out codes a logic "0," while the coding element 10146 which has been broken out codes a logic " L" Figure 7 shows, in a manner similar to Figure 5, the vertical height signal which is produced when the code carrier 10140 is scanned in the scanning direction 10149 by means of the probe 10 122 as a function of the scanning site, the v'ertical height having been obtained by integration of the acceleration signal which was determined by means of the piezoelement 1016 in the vertical direction. As in the case of Figure 5, here again, three different height levels are acquired, inthis case, thereference levelofthe inten-nediate areas 10144 having the average level height, while the logic "O"which has been codedby an existing coding element 10146 is formed by the highest level and the logic "I" which is coded by the coding element 10 146 which has been broken out is forined by the lowest height level. Here as well, the acquired height level of the logic "I" depends on the dimensions of the coding area 10142 and the geometry of the probe 1022. It is noted that the representation of Figure 7 is inverted with respect to the representation of Figure 5. While various embodiments in accordance with the present invention have been shown and described, it is understood that the invention is not limited thereto, and is susceptible to numerous changes and modifications as known to those skilled in the art. Therefore, this invention is not limited to the details shown and described herein, and includes all such changes and modifications as are encompassed by the scope of the appended claims.

Claims

CLAIMS 1. A vibration measurement device with an additional measurement capacity, comprising a pyroelectric effect vibration sensor which also acts as a temperature sensor based on pyroelectric effect for measuring the temperature at a measurement site in addition to measuring vibration at the site.
2. A device as claimed in claim 1 wherein the vibration sensor has predetermined bandwidth properties and filter properties by which the surface of a code carrier which is mechanically coded can be scanned so that, in addition to measuring vibration and temperature, a measurement site identification is obtained.
3. A measuring system comprising a device as claimed in claim 1 or claim 2, and a code carrier comprising a carrier base which has an attachment surface for attachment to a measurement site, and which is provided with at least one row of coding holes of different sizes for producing said magnetic flux deviations.
4. A measuring system comprising a device as claimed in claim I or claim 2, and a code carrier comprising a carrier base which has an attachment surface for attachment to a measurement site, wherein a series of bar-shaped coding elements and bar-shaped intermediate areas project from the carrier base in alternation and wherein a surface of the coding elements opposite the attachment surface has a level different from that of a surface of the intermediate areas opposite the attachment surface, the different surface levels of the coding elements being assigned different integers of a binary coding and the coding elements being connected to the carrier base to be detachable for changing the code produced by the series of elements and areas.
5. A vibration measuring device substantially as hereiribefore described with reference to Figs. 1, 8 and 9 or Figs. 4, 5, 8 and 9 or Figs. 6 to 9 of the accompanying drawings.

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6. A measuring device comprising a sensor for detecting vibrations and temperature at an article and a code reader for reading a code applied to the article, the reader being operable to read the code by use of a magnitude or quantity used or provided by the sensor in detection of vibrations.
7. A measuring system comprising a device as claimed in claim 6 and a code carrier which is readable by the reader of the device and securable to such article.