Method for testing a tube and testing apparatus therefor

Abstract

A method for testing a tube (4) by means of a testing apparatus (2) is specified, wherein the testing apparatus (2) has a first testing connection (6) and a second testing connection (8), to which the tube (4) is connected or has been connected, wherein the testing apparatus (2) has a media feed (10), by means of which a testing medium can flow into the tube (4) or can flow out of it, wherein the testing apparatus (2) has a first sensor (12), for a seal-tightness test, wherein the first sensor (12) is arranged in a flow path (12) of the testing medium, wherein a testing pressure (pt) for the tube (4) is set by means of the testing medium and then a number of measured values (14) relating to a parameter of the testing medium are generated by the first sensor (12), wherein the measured values (14) are used as a basis for determining a seal-tightness of the tube (4). The invention also specifies a corresponding testing apparatus (2).

Description

[0001] Description

[0002] Method for testing a hose and testing device therefor

[0003] The invention relates to a method for testing a hose and a corresponding testing device therefor.

[0004] Hoses are increasingly being used in vehicle electrical systems to perform additional functions. A hose is generally used to carry a medium from one end of the hose to the other. The medium is usually air or water. When a hose is fitted, e.g. in a motor vehicle or when assembling an on-board electrical system, it is possible that the hose may be bent, twisted, crushed or otherwise mechanically stressed. This may damage the hose, cause its connection to a component to leak, or impair the flow rate of the medium through the hose. Overall, this has a negative impact on the performance of the hose when used as intended. Against this background, it is desirable to check, i.e. test, a hose, particularly using an appropriate testing device.

[0005] A test fixture for testing a hose can generally have one or more of the following disadvantages: use of non-standardized sensors; complicated pneumatics and test topology; complicated software due to the required internal communication of the fixture during testing; difficult manufacturing, handling, maintenance and troubleshooting; limited accuracy, e.g. only blockages larger than 50 % of the hose diameter can be detected; high inaccuracy when testing the tightness of a hose, e.g. + / - 6 mbar when testing with 3 bar to 5 bar pressure; no active measurement of the flow rate (flow measurement), instead blockages are calculated, e.g. based on the pressure difference at the ends of the hose; high acquisition costs.

[0006] A device for testing a hose is described, for example, in DE 10 2013 226 191 B4. Using the device described there, hoses can be tested for leaks and deformation.

[0007] Against this background, it is an object of the invention to improve the testing of a hose. In particular, one or more of the aforementioned disadvantages are to be reduced or eliminated. Overall, an improved testing device and an improved method for testing a hose are to be provided.

[0008] The object is achieved according to the invention by a method for testing a hose by means of a testing device, wherein the testing device has a first test connection and a second test connection to which the hose is or will be connected, wherein the testing device has a media supply by means of which a test medium can flow into the hose or out of it. The test medium is suitably provided with the media supply, but this is not mandatory. The testing device has a first sensor for a tightness test, wherein the first sensor is arranged in a flow path of the test medium, wherein a test pressure for the hose is set by means of the test medium and then a number of (ieone or more) measured values ​​are generated for a parameter of the test medium, whereby the tightness of the hose is determined on the basis of the measured values ​​(if only one measured value is available).

[0009] The object is also achieved according to the invention by a testing device which is designed to carry out the method.

[0010] Advantageous embodiments, further developments, and variants are the subject of the dependent claims. The statements in connection with the method also apply mutatis mutandis to the test device, and vice versa. If steps of the method are specified implicitly or explicitly below, advantageous embodiments for the test device result from the fact that it is designed to perform one or more of these steps. For this purpose, the test device has, in particular, a correspondingly designed control unit, e.g., a microcontroller or a microcontroller unit.

[0011] The invention described here is based in particular on the device described in the aforementioned DE 10 2013 226 191 B4 and, in contrast, represents an alternative with specific advantages.

[0012] The process is also referred to as a test procedure or test method. The test device is also referred to as a test fixture or pipe test unit (PTU). The test device is suitably integrated, or can be integrated, into a test bench, particularly as a test module. Alternatively or additionally, the device can be used as a stand-alone device. In principle, the test device can be used to test several, even different, hoses one after the other.

[0013] The testing device is used in particular for testing water hoses and / or air hoses, especially compressed air hoses. Such water or air hoses are used in a vehicle, for example, to convey washer fluid from a reservoir to a washer fluid nozzle or to implement a massage function in a seat using compressed air. Accordingly, the hose is designed to convey water and / or air. The device is particularly unsuitable for testing brake hoses.

[0014] The hose is also referred to as a test specimen. The hose is intended, for example, for use in the electrical system of a motor vehicle as described above. The test device is not part of the motor vehicle; rather, the test is carried out with the test device outside of the intended use of the hose and in particular before the hose is installed. The two test connections are used to connect the hose to the test device. The connection is made before the process or as part of it. The hose generally has an outer wall which extends between two open ends and encloses a hollow space. The outer wall is made, in particular, from an elastic or flexible material so that the hose as a whole is flexible. The two open ends are each connected to one of the test connections.In principle, it is possible that the hose has more than two ends; in this case, the previous and following statements apply analogously and the test device has a corresponding test connection for each end of the hose.

[0015] In a suitable embodiment, the test device has two modules, namely a master module and a slave module, each of which has one of the test connections. The master module is distinguished from the slave module in particular in that the master module appropriately controls the slave module during the test. For this purpose, the master module and the slave module are connected via a suitable data connection, e.g. a CAN bus. Alternatively or additionally, the two modules communicate via the data connection in connection with a function other than simply controlling the slave module, e.g. in connection with the safety mechanism described below. In the following, it is assumed, without loss of generality, that the first test connection is integrated into the master module and the second test connection into the slave module.During the test, the two modules are connected to each other, primarily via the hose, but also via a data line. For a hose with more than two ends, the test device conveniently has several slave modules.

[0016] Furthermore, without loss of generality, it is assumed that the media supply is fully or partially integrated into the master module. If necessary, the two modules are then connected to each other via a line (not the hose to be tested), so that the slave module is also supplied from the media supply. A design in which the media supply is constructed in two parts, each with its own inlet for the master module and the slave module, is also suitable. The two inlets can be connected to the same media source or to independent media sources. Each inlet can be switchable, i.e., it can be opened and closed as required.

[0017] Depending on the detailed design of the test device and the method, the hose is filled with the test medium from the media supply during the test (testing in overpressure operation) or the test medium is evacuated from the hose using the media supply (testing in negative pressure operation). The media supply can generally be designed as a media source or sink. The important thing is that for testing using the media supply, the test medium can be supplied to or removed from the hose as required. The media supply either provides the test medium directly or merely a medium (working medium) with which the test medium is conveyed. Optionally, a filter for filtering the test medium is arranged between the media supply and the first test connection. The following assumes, without loss of generality, that the test is carried out in overpressure operation, i.e.The hose is filled with the test medium starting from the media supply. However, the same applies to testing in negative pressure mode, in which case the flow direction of the test medium is reversed accordingly. The alternative test in negative pressure mode is also described below. During testing in positive pressure mode, the pressure in the hose can be greater or lesser than the ambient pressure outside the hose. The terms "positive pressure" and "negative pressure" therefore primarily refer to the flow direction of the test medium and not necessarily to the pressure inside the hose.

[0018] The test medium is preferably air, regardless of whether the hose carries air, water, or another medium during subsequent, intended use. The media supply is therefore also referred to as the main air supply. The test medium generally flows into (or out of) the hose in the direction of flow.

[0019] In this case, the first sensor is integrated into a flow path for the test medium in order to measure a parameter of the test medium and output a corresponding measured value (more precisely: to measure a value of a parameter of the test medium and output a corresponding measured value). The test medium flows, for example, from the media supply first through the sensor and then through the test connection into the hose. Two configurations are particularly advantageous here, which are explained in more detail below.

[0020] The leak test particularly comprises measuring the parameter, i.e. generating one or more measured values ​​for the parameter, on the basis of which the leak tightness is determined. For the leak test (but not necessarily as part of it), the hose is first connected to the two test connections and the second test connection is closed so that no test medium can escape from the hose via this connection. Suitably, the second test connection is closed by means of a corresponding valve, which is in particular part of the slave unit. This valve is in particular arranged downstream of the second test connection. The leak test is then preferably carried out by means of one or more of the following steps: first, the test pressure is set, e.g. by setting a filling pressure in a first period of time, which then drops to the test pressure in a subsequent, second period of time.For this purpose, the first test connection is connected to the media supply for the first period in such a way that the test medium flows into the hose and the filling pressure is established at the end of the first period. The first period is therefore also referred to as the “filling time”. After that, the second period is simply a wait; this serves to stabilize the pressure inside the hose. The media supply is particularly separated from the test connection, e.g. by means of an appropriately switched valve (particularly in the master module upstream of the first test connection). The second period is therefore also referred to as the “stabilization time”. Typically, the pressure inside the hose drops slightly during the second period, i.e. in particular by 5% to 15%. The test pressure has then been established at the end of the second period.Subsequently, during a third period, the sensor measures the parameter at least once, but preferably repeatedly, and most preferably continuously. The sensor outputs corresponding measured values ​​as a function of time. The third period is therefore also referred to as the "measurement period." The measured values ​​measured during or at the end of the measurement period are then used to determine the tightness.

[0021] Appropriately, the tightness is then also assessed, and a rating is generated, which is output by the test device. For example, the tightness is assessed by comparing it with a limit value. Depending on the result of the comparison, a rating is then generated, which simply indicates, for example, whether the hose passed the leak test (pass) or failed (fail). The rating is then output via an output element (e.g., light, speaker, screen, etc.) of the test device.

[0022] In the following, a first and a second advantageous variant of the leak test are described.

[0023] In the first variant, the first sensor is a pressure sensor and the parameter is pressure. During the leak test, the pressure in the hose is measured directly as a function of time, whereby two measured values ​​at different times are generally sufficient. From these measured values, a pressure difference is then calculated, which is a measure of the tightness of the hose, particularly in conjunction with the measurement time. Thus, the tightness is determined by calculating the pressure difference. The leak test is therefore essentially based on a differential pressure measurement, i.e. the pressure drop within the hose is simply measured during the measurement time. Measuring the pressure as a function of time can also be understood as a leakage measurement.The actual pressure measurement is carried out with the first sensor outside the hose, but the pressure measured there corresponds in principle to the pressure inside the hose, so that this is effectively also measured. The pressure difference is then expediently compared with a limit value in order to assess the tightness. If the pressure difference exceeds the limit value (e.g. 1 mbar) during the measuring time (e.g. 10 s), then the hose is not sufficiently tight (fail), otherwise it is (pass). In the second variant, the first sensor is a flow sensor and the parameter is a flow rate. During the leak test, the pressure is therefore not measured, but the tightness is determined based on the flow rate during the measuring time, thus effectively carrying out a leakage measurement. In contrast to the previously mentioned pressure (difference) measurement, a flow measurement is carried out.The idea behind this is that if the hose is not leak-tight, the test medium will continually escape from the hose, allowing a continuous inflow of test medium which will then continue when the test pressure is set accordingly. This results in a flow rate which does not vanish, i.e. it is greater than 0 ml / min. In contrast, with a perfectly leak-tight hose, no test medium at all would escape and a flow rate of 0 ml / min would be established once the hose is completely filled. The flow rate reached after a certain time, in particular after the measuring time, is therefore a measure of the tightness. In principle, a single measured value is sufficient, e.g. at the end of the measuring time. It is advisable to choose a value other than zero as the limit value for assessing the tightness, e.g. 1.8 ml / min.If the flow rate falls below the limit value within the measuring time, then the hose is sufficiently tight (pass), otherwise it is not (fail).

[0024] The first variant (pressure measurement) is particularly more cost-effective than the second variant (flow measurement). However, the second variant is simpler than the first, particularly because no complicated calculations are required and the overall test time is shorter. In addition, the second variant has a higher level of measurement accuracy than the first variant and even smaller, especially localized, damage to the hose can be detected. The advantages of the second variant over the first variant also apply in particular to the device described in DE 10 2013 226 191 B4 mentioned above. The leak test detects, in particular, damage to the hose, i.e. leaks. Blockages, i.e. unwanted cross-sectional reductions such as blockages, kinks and the like, cannot be detected this way, but an additional flow test is suitable for this purpose.Therefore, as part of the method, it is expedient to also carry out a flow test in which the flow rate through the hose is measured in order to detect any blockages in the hose. The test device is then designed for two different test operations, namely the leak test already described (first test operation with the first sensor) and the additional flow test (second test operation with a different, second sensor). The two test operations are mutually exclusive, i.e. at any given time only either the leak test or the flow test can be carried out. Each of these two tests uses its own sensor. The additional flow test is optional and can be carried out before or after the leak test. However, combining a leak test with a flow test in a single test device is advantageous.

[0025] In a suitable embodiment, the testing device has a second sensor, which is a flow sensor for a flow test, namely for the aforementioned additional flow test. Preferably, a test pressure for the hose is set using the test medium and then a flow rate of the test medium is measured using the second sensor. In this respect, the flow test is identical to the leak test using a flow sensor, the above statements apply analogously, basically the same types of flow sensor are suitable for both tests, but preferably the two sensors have different measuring ranges. A further difference is that the second test connection is now open (i.e. the corresponding valve, e.g. downstream of the second test connection, is open) so that the test medium can flow out of the hose.The flow test specifically involves measuring the flow rate and assessing whether the hose is sufficiently clear. A flow rate is then determined from the measured values ​​(one or more) generated during the flow test during the measurement time, e.g., as the average of all measured values ​​or based on the course of the measured values ​​over time. This flow rate is then compared with a limit value or range of values ​​to assess whether the hose is blocked or something similar. If the flow rate is above the limit value or within the range of values, then there is no blockage or anything similar, i.e. the hose is sufficiently clear (pass); otherwise, the hose is blocked (fail).

[0026] Regardless of whether a flow test or a leak test is being conducted, a flow sensor, in a suitable design, uses a measurement method based on thermal heat transfer. The test medium flows over or around a controlled heated temperature sensor, thereby cooling it more or less depending on the flow rate. This effect then generates a measured value which, with appropriate calibration, indicates the actual flow rate.

[0027] In particular, the first and second sensors are not connected to each other, but are essentially independent of each other. However, the first and second sensors are both connected to the control unit, to which the measured values ​​are then output. This simplifies communication within the test device, as the two sensors do not need to communicate with each other and do not need to coordinate their operation. Advantageously, all communication takes place exclusively with the control unit.

[0028] Advantageously, a different test pressure is used for the flow test on the one hand and the leak test on the other. The flow test is preferably carried out at a lower test pressure of the test medium than the leak test. This is then a further difference between the two flow measurements described (one for the flow test and one for the leak test). Accordingly, a significantly higher test pressure is set for the leak test than for the pure flow test. The leak test depends on the intended use of the hose and regularly requires a test pressure of several bar, so the leak test is preferably carried out with a test pressure in the range of 2 bar to 5 bar (high pressure). The flow test, on the other hand, is preferably carried out with a test pressure in the range of 300 mbar to 500 mbar (low pressure).The idea behind this is that a flow sensor has an upper measurement limit for the flow rate. By using a correspondingly low test pressure during flow measurement, this upper limit is avoided. However, a high test pressure can still be used for leak testing, as the flow rate here depends solely on the tightness and is typically sufficiently low, ideally even 0 ml / min. For leak testing, the first sensor, if it is a flow sensor, expediently has an operating range of 2 ml / min to 100 ml / min. For flow testing, however, the second sensor preferably has an operating range of 10 L / min to 50 L / min. The flow rates achieved during testing are accordingly within these ranges, or even lower for leak testing.The limits for the evaluation are adapted accordingly to the respective work area.

[0029] The second sensor is preferably connected in parallel (i.e. parallel with respect to the flow direction of the test medium) to the first sensor. In a suitable embodiment, the second sensor is connected between the media supply and the first test connection and in parallel to the first sensor, so that the same media supply is used for the leak test and the flow test. Depending on which test is to be carried out, the first or the second sensor is then connected to the first test connection. For this purpose, the testing device has in particular a suitable switching element, e.g. a 3 / 2-way valve or a branch with two parallel valves. By means of the switching element, two separate measuring paths (e.g. measuring circuits) of the testing device are in particular implemented, namely a first measuring path with the first sensor for the leak test and a second measuring path with the second sensor for the additional flow test.The test device expediently has a proportional valve with which the test pressure is set. The proportional valve is arranged in particular between the media supply and the switching element and generally before a division of the flow path into the two different measuring paths. The proportional valve is used in particular to ensure that a different test pressure is set for the two tests. The proportional valve is used to set the test pressure accordingly depending on the test. In particular, the proportional valve reduces the pressure provided by the media supply to the pressure to be set for the flow measurement. The proportional valve is controlled accordingly for this purpose, in particular by the control unit. A precision regulator for setting the test pressure is particularly dispensed with; such a regulator is not required and is not present either.

[0030] In a suitable design, the proportional valve is a continuous valve, which, for example, with a proportional solenoid, allows not only discrete switching positions, but also a continuous transition of the opening degree from open to closed and / or vice versa. The proportional valve is particularly suitable for applications requiring a variable volume flow, such as in the test procedure described here. In particular, the proportional valve exhibits a nonlinear volume flow characteristic.

[0031] In a practical embodiment, a flow path of the test medium leads from the media supply via an optional filter to the proportional valve and finally to the switching element. The switching element has, for example, a branch which divides the flow path between the two measuring paths. On each measuring path, a valve is then arranged upstream of the respective sensor, for opening or closing the respective measuring path, depending on which test is to be carried out (see also the explanations above regarding the tests and the valves controlled accordingly). As an alternative to the branch and the two valves, a 3 / 2-way valve is also conceivable. Downstream of the sensors, the two measuring paths are reunited. Upstream of this, at least one of the measuring paths expediently contains an isolator which insulates the two measuring paths from one another, in particular separating them from one another.The isolator is suitably a valve, in particular a check valve, in one of the two measuring paths, specifically the one with the lower test pressure. In principle, the statements regarding the switching element upstream of the sensors also apply analogously to the isolator downstream of the sensors, and vice versa. Downstream of the sensors and the isolator, specifically after the measuring paths are joined, the flow path then leads to the first test connection and thus to the hose. Up to the first test connection, the flow path preferably runs entirely within the master module. Downstream of the hose, the flow path then leads to the second test connection, which is particularly part of the slave module. During the leak test, the flow path ends here. During the flow test, however, the flow path then leads through the second test connection and via a valve, e.g., into the environment or to the media supply, which then also serves as a media discharge and accordingly, e.g.has two lines, a supply line and a discharge line. The aforementioned valve is closed for the leak test.

[0032] One or both sensors are advantageously arranged upstream of the hose with respect to the flow direction of the test medium, so that the test medium flows through the respective sensor first and only then the hose, since otherwise the measured values ​​may be falsified by an interim compression of the test medium.

[0033] As already indicated above, as an alternative to supplying test medium from the media supply, it is also possible to test the hose under negative pressure, i.e. to evacuate the hose using the media supply and thus suck out the test medium. The flow direction is then reversed accordingly (and the terms "downstream" and "upstream" used above are then to be interchanged). This is possible for both the leak test and the additional flow test. In a suitable embodiment, for such negative pressure operation of the test device, a Venturi nozzle is connected between the media supply and the first test connection for testing the hose under negative pressure (negative pressure operation). The Venturi nozzle is expediently connected downstream (the flow direction of the test medium is now reversed) of the two measuring paths, in particular downstream of the proportional valve. The Venturi nozzle is part of the test device, in particular of the master module.If an additional flow test with a second sensor is also possible, the Venturi nozzle is also arranged between the media supply and the switching element in order to implement negative pressure operation for both sensors. The Venturi nozzle is then operated with a medium (in particular air) which is provided by the media supply. In this respect, the flow path from the media supply to the Venturi nozzle is identical; however, the medium from the media supply is not, strictly speaking, the test medium in negative pressure operation; rather, this is taken from the hose, i.e. during the flow test it is sucked in through the second test connection, for example from the environment and / or via the access to the media supply, and during the leak test it is sucked in from the hose, and if there is damage, then via this from the environment.

[0034] The testing device expediently has a safety mechanism which is designed to prevent removal, e.g. pulling off, of the hose from the test connections during the test or at least to carry this out safely. The use of the safety mechanism is fundamentally independent of which test is possible and is carried out and how this is specifically done. In a particularly preferred embodiment, the testing device has a presence sensor for each of the first test connection and the second test connection, i.e. a presence sensor for each of the test connections. The respective presence sensor emits a presence signal if a hose is connected to the respective test connection. The testing device also has a locking mechanism to lock the hose to the first test connection and to the second test connection, i.e. to secure it against removal.For this purpose, the locking mechanism has, in particular, two locking elements, one for each test connection. In a suitable embodiment, the locking elements are two hook cylinders. By “locking,” in particular, it is not meant that the test connection is opened or closed for the test medium in order to allow it to flow into or out of the hose; this is suitably achieved using a corresponding valve if necessary. It is expedient, in particular, to measure with the control unit whether both presence signals are present simultaneously, and if so, the locking mechanism is actuated so that the hose is locked. The presence signals are received, in particular, by the control unit and evaluated as described above, and the control unit then controls the locking mechanism accordingly.The presence signal, for example, is a simple electrical voltage that is emitted by the corresponding presence sensor.

[0035] In a practical embodiment, the locking device for the first test connection and the second test connection each has a locking element (as already mentioned above) and a closing valve, i.e. a separate closing valve for each locking element. To lock the hose, a respective closing valve is opened and thereby the respective locking element is actuated, in overpressure operation by means of the test medium, in vacuum operation by means of the medium provided by the media supply. Accordingly, air is preferably used to lock the hose, in particular compressed air; alternatively, the locking element is actuated electrically. Unlocking takes place in the opposite direction, e.g. by means of a manually actuated unlocking button or automatically in the event of a failure of the test device, in particular in the event of a failure of the test table signal.

[0036] In principle, it is preferred if the hose is locked at both test connections, but it is also possible and also advantageous to have an embodiment in which the hose is only locked at one test connection, so that then only one presence sensor and one presence signal are present and the lock has only one locking element and only one closing valve.

[0037] Suitably, the hose is only locked if a test table signal is present in addition to the presence signals. The test table signal signals, in particular, that the test device is ready for operation. The test table signal is received and evaluated, in particular by the control unit, in analogy to the presence signals. In connection with the safety mechanism, the control unit thus recognizes the following three parameters: status of both presence signals (present / not present), status of the test table signal (present / not present), status of the release button (pressed, not pressed). The locking is then controlled by the control unit according to these three parameters, i.e. the hose is locked or unlocked, i.e. released. The control unit is preferably capable of operating independently, so that all safety-relevant situations are immediately recognizable, e.g.If, during a test, an operator accidentally unlocks one end of the hose or accidentally presses the release button, or if the test table signal fails, or if the test is terminated prematurely. Such situations are typically dangerous, especially at high test pressures such as in the case of a leak test. The control unit conveniently detects one or more of these situations automatically and depressurizes as quickly as possible. Only then is the hose unlocked.

[0038] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In each case, the following schematically show:

[0039] Fig. 1 a test device,

[0040] Fig. 2 a variant of the test device,

[0041] Fig. 3 a variant of the test device,

[0042] Fig. 4 a method,

[0043] Fig. 5 Pressure as a function of time during a leak test,

[0044] Fig. 6 Flow rate as a function of time during a leak test.

[0045] 1 to 3 each show an exemplary embodiment of a testing device 2 which is designed to carry out a method for testing a hose 4 by means of such a testing device 2. An exemplary embodiment of the method is illustrated in Fig. 4. The testing device 2 has a first test connection 6 and a second test connection 8, to which the hose 4 is or will be connected. The testing device 2 further has a media supply 10, by means of which a test medium can flow into the hose 4 or out of it. In Figs. 1 and 2, the test medium is provided with the media supply 10, but this is not mandatory. The testing device 2 additionally has a first sensor 12 for a leak test. The first sensor 12 is arranged in a flow path 14 of the test medium.Using the test medium, a test pressure pt is set for the hose 4 in a first step S1. Subsequently, in a second step S2, a number of (i.e., one or more) measured values ​​16 for a parameter of the test medium are generated using the first sensor 12. Based on the measured values ​​16, the tightness of the hose 4 is determined in a third step S3. The testing device also has a control unit 18.

[0046] The test medium in this case is air and generally flows into the hose 4 in one flow direction; the flow direction is illustrated in Figs. 1 to 3 by arrowheads on the flow path 14.

[0047] The test with the test device 2 is performed outside the intended use of the hose 4 and before it is installed. The two test connections 6, 8 are used to connect the hose 4 to the test device 2. The connection takes place before the procedure or as part of it. The hose 4 is not shown in detail in the figures, but generally has an outer wall that extends between two open ends and encloses a hollow space. The two open ends are each connected to one of the test connections 6, 8.

[0048] The test devices 2 shown here as examples have two modules 20, 22, namely a master module 20 and a slave module 22, each of which has one of the test connections 6, 8. The master module 20 is distinguished from the slave module 22 in that the master module 20 has the control unit 18 and thus appropriately controls the slave module 22 during the test. For this purpose, the control unit 18 is divided into two sub-units in the master module 20 and the slave module 22; the sub-units are connected via a data connection 24. In the exemplary embodiments shown here, only one slave module 22 is shown in each case; however, the explanations in connection with the figures are also applicable analogously to test devices 2 with several such slave modules 22. All slave modules 22 are then controlled by the master module 20.

[0049] In the present case, the media supply 10 is designed in two parts, each with its own access 26 for the master module 20 and the slave module 22. The two accesses can be connected to the same media source (Fig. 1 to 3) or to independent media sources (not shown).

[0050] Depending on the detailed design of the test device 2 and the method, the hose 4 is filled with the test medium from the media supply 10 during the test (testing in overpressure mode, Fig. 1 and 2) or the test medium is evacuated from the hose 4 using the media supply 10 (testing in negative pressure mode, Fig. 3). The media supply 10 either provides the test medium directly, as in Fig. 1 and 2, or merely a medium (working medium) with which the test medium is conveyed, as in Fig. 3. Optionally, a filter 28 for filtering the test medium is arranged between the media supply 10 and the first test connection 6.

[0051] First, without limiting the generality, we assume a test in overpressure mode as shown in Figs. 1 and 2, i.e., hose 4 is filled with the test medium starting from the media supply 10. However, the explanations also apply analogously to the test in negative pressure mode, in which case the flow direction (indicated by arrows in the figures) of the test medium is reversed accordingly. The alternative test in negative pressure mode is described in more detail below with reference to Fig. 3.

[0052] The first sensor 12 is integrated into a flow path 14 for the test medium to measure a parameter of the test medium and output a corresponding measured value 14. The test medium flows from the media supply 10, first through the sensor 12, and then through the test connection 6 into the hose 4.

[0053] The leak test now comprises measuring the parameter, i.e. generating one or more measured values ​​14 for the parameter, on the basis of which the leak tightness is determined. For the leak test (but not necessarily as part of it), the hose 4 is first connected to the two test connections 6, 8 and the second test connection 8 is closed so that no test medium can escape from the hose 4 via this. In the present case, the second test connection 8 is closed by means of a corresponding valve 30, which is part of the slave unit 22. The leak test is then carried out, for example, as follows, see also Fig. 5 and 6: first, the test pressure pt is set by setting a filling pressure pf in a first period t1, which then drops to the test pressure pt in a subsequent, second period t2.For this purpose, the first test connection 6 is connected to the media supply 10 over the first period t1 in such a way that the test medium flows into the hose 4 and the filling pressure pf is established at the end of the first period t1. The first period t1 is correspondingly also referred to as the "filling time". After that, the second period t2 is simply waited for; this serves to stabilize the pressure p inside the hose 4. The second period t2 is correspondingly also referred to as the "stabilization time". At the end of the second period t2, the test pressure pt has then been established. Subsequently, during a third period t3, the parameter is measured once, repeatedly, or continuously using the sensor 12, and the sensor 12 outputs corresponding measured values ​​14 as a function of time t. The third period t3 is therefore also referred to as the "measurement time".After the first period of time, the valve 38 upstream of the first sensor 12 is also closed, thereby separating the hose 4 from the media supply 10, at least during the measurement. The measured values ​​14 measured during or at the end of the measuring time t3 are then used to determine the tightness. The tightness is then also evaluated, and a rating is generated, which is output by the testing device 2. For example, the tightness is evaluated by a comparison with a limit value g. Depending on the result of the comparison, a rating is then generated, which, for example, simply indicates whether the hose 4 passed the leak test (pass) or failed (fail). The rating is then output using an output element of the testing device 2 (not shown).

[0054] In the following, a first and a second variant of the leak test are described with reference to Figs. 5 and 6.

[0055] In the first variant, the first sensor 12 is a pressure sensor and the parameter is a pressure. This is implemented in Fig. 1, while Fig. 5 then shows the course of the pressure p as a function of time t for this test device 2 during the leak test. The pressure p in the hose 4 is measured directly as a function of time t, whereby two measured values ​​14 at different times t are generally sufficient. From these measured values ​​14, a pressure difference pd is then suitably calculated, which, in conjunction with the measuring time t3, is a measure of the tightness of the hose 4. The actual measurement of the pressure p is carried out with the first sensor 12 outside the hose 4, but the pressure p measured there corresponds in principle to the pressure p inside the hose 4, so that this is effectively also measured. The pressure difference pd is then compared with a limit value g in order to evaluate the tightness.If the pressure difference pd exceeds the limit value g during the measuring time t3, then the hose 4 is not sufficiently tight (fail), otherwise it is (pass).

[0056] In the second variant, the first sensor 12 is a flow sensor and the parameter is a flow rate Q. This is implemented in Fig. 2, and Fig. 6 then shows the course of the flow rate Q as a function of time t during the leak test for this test device 2. The leak tightness is determined based on the flow rate Q during the measuring time t3. If the hose 4 is not tight, the test medium continuously escapes from the hose 4, allowing a continuous inflow of test medium, which is then continuous when the test pressure pt is set accordingly. This results in a correspondingly non-zero flow rate Q, i.e., it is greater than 0 ml / min, as can be seen in Fig. 6. In contrast, with a perfectly tight hose 4, no test medium at all would escape, and after the hose 4 is completely filled, a flow rate Q of 0 ml / min would be established (not shown).The flow rate Q, which is reached after a certain time t, e.g., after the measurement time t3, is accordingly a measure of the tightness. In principle, even a single measured value 14 is sufficient, e.g., at the end of the measurement time t3. A value other than zero is chosen as the limit value g for assessing the tightness. If the flow rate Q falls below the limit value g within the measurement time t3, then the hose 4 is sufficiently tight (pass, solid line in Fig. 6); otherwise, it is not (fail, dashed line in Fig. 6).

[0057] The leak test detects damage to the hose, i.e. leaks. However, blockages, i.e. unwanted reductions in cross-section such as blockages, kinks and the like, cannot be detected this way; instead, in this case, an additional flow test is carried out in which the flow rate Q through the hose 4 is measured. The test device 2 is then designed for two different test modes, namely the leak test already described (first test mode with the first sensor 12) and the additional flow test (second test mode with a second sensor 32). The two test modes are mutually exclusive, i.e. at a given time only either the leak test or the flow test can be carried out. Each of these two tests uses its own sensor 12, 32. The additional flow test is optional and can be carried out before or after the leak test.

[0058] The test device 2 shown as an example in Fig. 2 has a second sensor 32, which is a flow sensor for the aforementioned additional flow test. The measurement of the flow rate Q is basically analogous to the measurement of the flow rate Q with the first sensor 12, in the event that this is a flow sensor. Analogous to the procedure already described in connection with Fig. 6, a test pressure pt for the hose 4 is set using the test medium and then a flow rate Q of the test medium is measured using the second sensor 32. One difference from the flow measurement in the context of the leak test, however, is that the second test connection 8 is now open (i.e. the corresponding valve 30 is open) so that the test medium can flow out of the hose 4 there. The flow test comprises measuring the flow rate Q and assessing on this basis whether the hose 4 is sufficiently free.A flow rate Q is then determined from the measured values ​​14 generated during the measuring time t3, e.g., as the mean value of all measured values ​​14 or based on the course of the measured values ​​14 as a function of time t. This flow rate Q is then compared with a limit value g or value range in order to assess whether the hose 4 is blocked or the like. If the flow rate Q is above the limit value g or within the value range, then there is no blockage or the like, i.e., the hose 4 is sufficiently clear (pass); otherwise, the hose is blocked (fail).

[0059] The first and second sensors 12, 32 are not connected to each other, but operate independently of each other. However, the first and second sensors 12, 32 are both connected to the control unit 18, to which the measured values ​​14 are then output. All communication takes place exclusively with the control unit 18.

[0060] In the present case, a different test pressure pt is used for the flow test on the one hand and for the leak test on the other. More precisely, the flow test is carried out at a lower test pressure pt than the leak test. This is a further difference between the two flow measurements described (one for the flow test and one for the leak test). The leak test is carried out, for example, with a test pressure pt in the range from 2 bar to 5 bar (high pressure), while the flow test is carried out, for example, with a test pressure pt in the range from 300 mbar to 500 mbar (low pressure). In the exemplary embodiments shown, the second sensor 32 is connected in parallel (i.e. parallel with respect to the flow direction of the test medium) to the first sensor 12.The second sensor 32 is connected between the media supply 10 and the first test connection 6 and parallel to the first sensor 12, so that the same media supply 10 is used for the leak test and for the flow test. Depending on which test is to be carried out, the first or the second sensor 12, 32 is then connected to the first test connection 6; for this purpose, the test device 2 has a suitable switching element 34, in this case a branch 36 with two parallel valves 38. By means of the switching element 34, two separate measuring paths M1, M2 (e.g. measuring circuits) of the test device 2 are also realized, namely a first measuring path M1 with the first sensor 12 for the leak test and a second measuring path M2 with the second sensor 32 for the additional flow test.

[0061] In addition, the test devices 2 shown here have a proportional valve 40, e.g., a continuous valve, with which the test pressure pt is set. The proportional valve 40 is arranged between the media supply 10 and the switching element 34 and generally before the flow path 14 is divided into the two different measuring paths M1, M2. The proportional valve 40 ensures that a different test pressure pt is set for the two tests. The proportional valve 40 is controlled accordingly by the control unit 18.

[0062] Overall, in Figs. 1 and 2, the flow path 14 of the test medium leads from the media supply 10 via the optional filter 28 to the proportional valve 40 and finally to the switching element 34, which divides the flow path 14 between the two measuring paths M1, M2. On each measuring path M1, M2, a valve 38 is arranged upstream of the respective sensor 12, 32 to open or close the respective measuring path M1, M2, depending on the test to be performed. Downstream of the sensors 12, 32, the two measuring paths M1, M2 are reconnected. The measuring path M2 contains an additional insulator 42 downstream of the second sensor 32. Downstream of the sensors 12, 32 and the insulator 42, especially after the merging of the measuring paths M1, M2, the flow path 14 then leads to the first test connection 6 and thus to the hose 4. Up to the first test connection 6, the flow path 14 runs entirely within the master module 20.Downstream of the hose 4, the flow path 14 then leads to the second test connection 8, which is part of the slave module 22. During the leak test, the flow path 8 ends here. During the flow test, however, the flow path 14 then leads through the second test connection 8 and via the valve 30, e.g. into the environment or to the media supply 10 (both possibilities are shown as examples in the figures, but it is sufficient if one of them is implemented). In the latter case, the media supply 10 then serves as a media discharge and accordingly has, for example, two lines, a supply line and a discharge line (not explicitly shown). For the leak test, however, the aforementioned valve 30 is closed.

[0063] In the present case, both sensors 12, 32 are arranged upstream of the hose 4 with respect to the flow direction of the test medium, so that the test medium first flows through the respective sensor 12, 32 and only then through the hose 4, since otherwise the measured values ​​14 may be falsified by an interim compression of the test medium.

[0064] As already indicated, as an alternative to supplying test medium from the media supply 10, it is also possible to test the hose 4 under negative pressure, i.e. to evacuate the hose 4 using the media supply 10 and thus to suck out the test medium. The flow direction is then reversed accordingly; an exemplary embodiment of this is shown in Fig. 3. First of all, the previous explanations for Figs. 1 and 2 also apply analogously to Fig. 3. For negative pressure operation, a Venturi nozzle 44 is connected between the media supply 10 and the first test connection 6 for testing the hose 4 under negative pressure (negative pressure operation). The Venturi nozzle 44 is connected in the master module 20 downstream of the two measuring paths M1, M2 and downstream of the proportional valve 40. The Venturi nozzle 44 is then operated with a medium which is provided by the media supply 10.In this respect, the flow path from the media supply 10 to the Venturi nozzle 44 is identical, but the medium from the media supply 10 is strictly speaking not the test medium during negative pressure operation, but rather is taken from the hose 4.

[0065] The test devices 2 shown here additionally have an optional safety mechanism which is designed to prevent removal, e.g. pulling off, of the hose 4 from the test connections 6, 8 during the test. The use of the safety mechanism is fundamentally independent of which test is possible and is carried out and how this is specifically done. In the embodiments shown here, the test device 2 has a presence sensor 46 for each of the first test connection 6 and the second test connection 8, i.e. a presence sensor 46 for each of the test connections 6, 8. The respective presence sensor 46 outputs a presence signal if a hose 4 is connected to the respective test connection 6, 8. Furthermore, the test device 2 has a locking mechanism for locking the hose 4 to the first test connection 6 and to the second test connection 8.For this purpose, the locking mechanism has two locking elements 48, one for each test connection 6, 8. The locking elements 48 are, for example, hook cylinders. The control unit 18 measures whether both presence signals are present simultaneously and, if so, the locking mechanism is actuated, so that the hose 4 is locked. In addition to the locking elements 48, the locking mechanism for the first test connection 6 and the second test connection 8 has a closing valve 50. To lock the hose 4, a respective closing valve 50 is opened, thereby actuating the respective locking element 48, in overpressure operation by means of the test medium, and in vacuum operation by means of the medium provided by the media supply 10.

[0066] The figures show that the hose 4 is locked to both test connections 6, 8, but a configuration not shown is also possible and also advantageous, in which the hose 4 is only locked to one test connection 6, 8.

[0067] In this case, the hose is only locked if, in addition to the presence signals, a test table signal 52 is present, which indicates that the test device 2 is ready for operation. The test table signal 52 is received and evaluated by the control unit 18 in the same way as the presence signals.

[0068] List of reference symbols

[0069] 2 Test device

[0070] 4 hose

[0071] 6 first test connection

[0072] 8 second test connection

[0073] 10 Media supply

[0074] 12 first sensor (for leak test)

[0075] 14 Flow path

[0076] 16 measured values

[0077] 18 Control unit

[0078] 20 Master Module

[0079] 22 Slave module

[0080] 24 Data connection

[0081] 26 Access

[0082] 28 filters

[0083] 30 valve

[0084] 32 second sensor (for flow testing)

[0085] 34 Switching element

[0086] 36 branching

[0087] 38 Valve

[0088] 40 Proportional valve

[0089] 42 Insulator

[0090] 44 Venturi nozzle

[0091] 46 Presence sensor

[0092] 48 Locking element

[0093] 50 closing valve

[0094] 52 Test table signal g limit

[0095] M1 first measuring path

[0096] M2 second measuring path p pressure pd pressure difference pf filling pressure pt test pressure

[0097] Q flow rate

[0098] S1 first step S2 second step

[0099] S3 third step t time t1 first period, filling time t2 second period, stabilization time t3 third period, measuring time

Claims

Claims 1. Method for testing a hose (4) by means of a testing device (2), a. wherein the testing device (2) has a first test connection (6) and a second test connection (8) to which the hose (4) is or will be connected, b. wherein the testing device (2) has a media supply (10) by means of which a test medium can flow into or out of the hose (4), c. wherein the testing device (2) has a first sensor (12) for a leak test, wherein the first sensor (12) is arranged in a flow path (14) of the test medium, d. wherein a test pressure (pt) for the hose (4) is set by means of the test medium and then a number of measured values (14) for a parameter of the test medium are generated with the first sensor (12), e. wherein a leak tightness of the hose (4) is determined on the basis of the measured values (14).

2. The method according to claim 1, wherein the first sensor (12) is a pressure sensor and the parameter is a pressure (p).

3. The method according to claim 1, wherein the first sensor (12) is a flow sensor and the parameter is a flow rate (Q).

4. Method according to one of claims 1 to 3, wherein the testing device (2) has a second sensor (32) which is a flow sensor for a flow test, wherein a test pressure (pt) for the hose (4) is set by means of the test medium and then a flow rate (Q) of the test medium is measured with the second sensor (32).

5. The method according to claim 4, wherein the flow test is carried out at a lower test pressure (pt) of the test medium than the leak test.

6. The method according to claim 4 or 5, wherein the second sensor (32) is connected in parallel to the first sensor (12).

7. The method according to claim 6, wherein the test device (2) has a proportional valve (40) with which the test pressure (pt) is adjusted.

8. Method according to one of claims 1 to 7, wherein a Venturi nozzle (44) is connected between the media supply (10) and the first test connection (6) for testing the hose (4) with negative pressure.

9. The method according to one of claims 1 to 8, wherein the testing device (2) for the first test connection (6) and the second test connection (8) each has a presence sensor (46) which emits a presence signal if a hose (4) is connected to the respective test connection (6, 8), wherein the testing device (2) has a lock to lock the hose (4) to the first test connection (6) and to the second test connection (8), wherein it is measured whether both presence signals are present simultaneously and, if this is the case, the lock is actuated so that the hose (4) is locked.

10. Method according to claim 9, wherein the locking device for the first test connection (6) and the second test connection (8) each has a locking element (48) and a closing valve (50), wherein in order to lock the hose (4) a respective closing valve (50) is opened and thereby the respective locking element (48) is actuated.

11. Method according to one of claims 9 or 10, wherein the hose (4) is only locked if a test table signal (52) is present in addition to the presence signals.

12. Testing device (2) which is designed to carry out a method according to one of claims 1 to 11.

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