DE102022000766B3 - bang pressure simulator - Google Patents

Abstract

A blast pressure simulator is presented, having a ring-shaped base element and a button, characterized in that the ring-shaped base element is pushed over a blast pressure sensor, the front side of the blast pressure sensor rests against the ring-shaped floor element, the button assumes a magnetically held, disengaged position, the button after assumes an engaged position after overcoming the magnetic force by a triggering force, the button or a magnet hits the annular floor element when assuming the engaged position to generate structure-borne noise and the structure-borne noise simulates a bang pressure between 180 dB and 185 dB.

Description

The invention relates to a blast pressure simulator for the reproducible checking of installed measuring chains for one-off bang events, in particular explosions.

Bang pressure measurement chains are regularly used to measure the sound pressure level of bang events, in particular explosions or projectile impacts. Incidents of a bang are often carefully planned and are regularly unique and cannot be repeated. The dynamic range of such pop pressure events is often around 183 dB in relation to the sound pressure of the hearing threshold of 20 µPa.

Such a bang pressure measurement chain regularly includes a bang pressure transducer, which converts a bang pressure into an electrical signal, a signal line for transmitting the electrical signal, and evaluation electronics that evaluate and display the signal.

Acoustic measurement chains are usually checked before the acoustic event to be measured. For this purpose, for example, a similar acoustic event can be generated and the evaluation electronics can be used to determine whether all measurement chains offer plausible representations. Furthermore, the evaluation electronics regularly have test programs that can confirm a correct connection between the evaluation electronics and the sensors.

The disclosure document DD 273 369 A3 discloses an arrangement for calibrating structure-borne noise monitoring devices, characterized in that an impact pulse generator is arranged on the system parts to be monitored, which when excited by the pulse generator connected to it emits impact pulses onto the wall of the system parts, the firing pin of the impact pulse generator being mechanically rigid with a pulse measurement value pickup is coupled, from which the measured pulse values reach a measuring device and are displayed by a display device connected to it; so that a predetermined measured pulse value is set by varying the excitation of the impact pulse generator using a pulse generator,

From the translation of the French publication FR 2 704 459 A1 is a calibrated shock generator with a mass intended to strike an element forming an anvil, characterized in that it comprises a ferromagnetic core that supports the mass and an electromagnet that moves the core axially and the Mass from a rest position to a position where the mass impacts the anvil forming element, this generator also comprising means for recovering and holding an anvil, the core and the mass in their rest position after the mass has impacted the mold element.

The arrangements are known for use in monitoring primary circuits in nuclear power plants.

The published application discloses the comparable generation of sound events DE 33 22 625 A1 a method and a device for checking and/or calibrating acoustic monitoring devices. A calibration sound source is proposed, which serves in particular to simulate leakage noises in steam generators. Gas is blown through a nozzle into the liquid via a T-piece, which ends in a liquid container on one side. The gas is supplied via the transverse channel of the T-shaped molded part. The free end of the T-piece can be coupled to the structure of a component to be monitored. The recoil noise of the gas exiting the nozzle into the liquid can thus be transmitted backwards to a component where it is used to calibrate the acoustic monitoring system. The device has the advantage that leakage noises can be realistically simulated.

The disadvantage of this solution is that the sound event must be repeatable. This is the case with the flow noise of fluids, but not with explosions.

From the disclosure document DE 199 47 583 A1 Therefore, a sound pressure calibrator is known that can be calibrated independently of the actual event and is also suitable for sound pressures above 124 dB and can be adapted to the built-in sound pressure sensor. This object is achieved according to the invention in that the sound pressure calibrator consists of a pistonphone and a high-pressure adapter connected to the output of the pistonphone, that the high-pressure adapter acts as a resonator and that the high-pressure adapter is connected soundproof with a widened adapter opening to the sound pressure sensor used in the structure . The solution finds application in a sound pressure calibrator for calibrating a sound pressure transducer integrated into a structure.

A signal is recorded parallel to the actual measuring chain and the values are compared in order to calibrate the measuring chain to be examined. A disadvantage of the device is that no signal can be generated. The solution is to Kon trolling of measurement chains for one-time bang events is also not suitable.

The European patent specification EP 0 276 407 B1 discloses a device for calibrating a structure-borne noise monitoring system, consisting of a ram which is to be moved by electromagnets against a body which carries sensors of a structure-borne noise monitoring system for monitoring the body, the ram comprising an acceleration coil for accelerating the Plunger is arranged towards the body and connected to a control unit for controlling the movement of the ram. The device is characterized in that the ram is arranged in the housing, comprising a lifting coil, by means of which the ram can be moved away from the body against a stop on the housing, and is connected to the control unit, which for this purpose is connected to the stop and the impact point of the Plunger arranged contacts is connected.

Next is from the disclosure document DD 237 373 A1 an arrangement for the electromechanical calibration of structure-borne noise measuring chains with an excitation source which excites the sensors of the measuring chain in a defined manner and to whose signals the sound emissions recorded at a selected measuring point via the measuring chain are related for correction, characterized in that an electromechanical falling body pulse generator is connected in series with a Input device, counting device, a clock generator and an amplifier is coupled and is arranged at the measurement location on the selected measurement object in the immediate vicinity of structure-borne noise sensors also fixed on this.

Both calibration devices have the disadvantage of being dependent on an external power supply.

Finally, an acoustic precision calibrator is presented on the website of Synotech, Hückelhoven, www.synotech.de. The CAL 250 model emits an output level of 114.0 dB at a frequency of 250 Hz. The battery-powered device is suitable for 1-inch microphones and, in conjunction with the appropriate adapters, also for 1/2", 1/4" and 1/ 8" microphones and sound level meter.

The disadvantage of this solution is that the condenser microphones to be calibrated are not suitable for detonations. The measuring range for PCB pressure sensors for blasts starts at around 155-160 dB. Below these sound values, the quartz is not excited.

The object of the invention is therefore to propose a blast pressure simulator for the reproducible checking of installed measurement chains for one-off bang events, in particular blasting, which is operated without external energy sources.

This object is solved by the characterizing features of the main claim. Advantageous configurations are described in the dependent claims.

The advantage of the invention lies in the fact that no bang pressure is generated, but rather an event of approximately 183 dB is suggested according to the invention by structure-borne noise. In order to obtain a defined vibration, a resistance must be overcome to generate it, which requires a corresponding force.

In order to prevent influences due to the sound transmission, the vibration is transmitted directly as structure-borne noise from the blast pressure simulator to the sound pickup. For this purpose, a cover is placed over the blast pressure sensor by the blast pressure simulator and the end faces of the components are brought into contact. The signal pulse is generated and transmitted reproducibly.

Experience has shown that blast pressure transducers with an average recording range of around 170 - 190 dB are used in the harsh environment of blasting. It is advantageous to also generate the control pulse in the middle measuring range. According to the invention, the control pulse is therefore generated and checked at around 180-185 dB.

A simple and robust embodiment of the invention is achieved if the vibration generator is a mechanical button. By pressing the button to the stop, a structure-borne vibration is transmitted to the bang pressure sensor, which suggests a bang pressure in the range of around 183 db.

In order to generate the measured value in a reproducible manner, the probe is equipped with a retention force that must first be overcome. Since the overcoming force is always the same, the actuating force with which the button is pressed to the stop and which generates the structure-borne noise is also the same. The same actuation force produces the same impulse on the same stop, so that the output impulse of the pop pressure simulator is identical with each actuation. The retaining force is advantageously generated by a magnet. A magnet has the advantage that the magnetic field decreases quickly with increasing distance and the button after overcoming the restraining force on its way to the stop does not oppose anything.

In this way, the button can generate an undamped signal pulse on impact. Of course, the magnet can also be moved by parts of the button and in turn generate structure-borne noise on impact.

The following functional sequence is described for better understanding. The bang pressure simulator is grasped by the operator's hand with the index and middle fingers. The thumb touches the pressure surface of the button. The button is held in the disengaged position by magnetic force. The bang pressure simulator is pushed over the bang pressure transducer until the front side of the bang pressure transducer is in contact with the bang pressure simulator. By pressing the button, the release force increases until it overcomes the magnetic force and the button is moved from the disengaged to the engaged position. As soon as the button or the magnet hits the stop of the engaged position, structure-borne noise is generated, which is transmitted to the pop pressure sensor and corresponds to a pop pressure of 180-185 dB. The structure-borne noise is converted into an electrical signal by the blast pressure transducer and can be used as a reference signal for function testing and calibration.

It shows the only one 1 a blast pressure simulator according to the invention in a lateral sectional view

It shows 1 a blast pressure simulator 1, which surrounds a blast pressure sensor 2 in a form-fitting manner and rests against the end face 3. The bang pressure simulator 1 has an annular base element 4 . The annular bottom element 4 is designed with a bearing surface 5 to be held by the index and middle fingers of the operator's hand. On the annular base element 4, a button 6 is mounted. The button 6 is to be actuated by the operator's thumb. The button 6 has a magnet 7 . The magnet 7 is designed to require a defined actuating force for actuating the button 6 . In a disengaged position, the magnet 7 has a non-positive connection to the cover 8 made of magnetic material. By pressing the button 6, the magnetic force is overcome and the magnet 7 hits the ring-shaped base element 4 to generate structure-borne noise.

Reference List

1

bang pressure simulator

2

blast pressure transducer

3

face

4

floor element

5

contact surface

6

button

7

magnet

8th

Lid

Claims (2)

Impact pressure simulator (1), having an annular base element (4) and a button (6), characterized in that - the annular base element (4) is pushed over an impact pressure transducer (2), - the end face (3) of the impact pressure transducer (2) rests against the ring-shaped base element (4), - the button (6) assumes a disengaged position held by magnetic force, - the button (6) assumes an engaged position after the magnetic force has been overcome by a triggering force, - the button (6) or a magnet (7) hits the ring-shaped floor element (4) when it assumes the engaged position to generate structure-borne noise and - the structure-borne noise simulates a bang pressure of between 180 dB and 185 dB. Procedure with a pop pressure simulator (1). claim 1 , characterized in that - an annular base element (4) of a blast pressure simulator (1) is pushed over a blast pressure transducer (2), - until the end face (3) of the blast pressure transducer (1) on the annular base element (4) of the blast pressure simulator (1) is present, - a release force increases when a button (6) is pressed, - until it overcomes a magnetic force and - the button (6) is moved from a disengaged to an engaged position, - as soon as the button (6) or a magnet ( 7) hit the stop of the engaged position, a structure-borne noise is generated, - which is transmitted to the blast pressure transducer (2) and simulates a blast pressure of 180-185 dB.

Images