DK2924286T3 - Test device for pumps - Google Patents

Description

Description [0001] The invention relates to a test device for pumps as well as a method for testing pumps.

[0002] In various systems, such as, for example, heating systems and domestic water heating systems, pumps are used, which must operate under changing temperatures. The temperature range for such a circulation pump may fluctuate by 40°C or more. To ensure the functionability even under such conditions, pumps are tested with acceptance tests or tests according to a temperature cycle are performed. In the process, the pump must circulate a liquid, whose temperature changes in intervals, for example between 90°C and 50°C, in a test rig, to which it is connected, for example for a test period of several hundred hours.

[0003] While this test method is regarded as reliable, it involves certain problems in practice. The corresponding regulations (e.g. DIN EN 16297-1) provide a comparatively rapid cooling and heating and the reaching of defined temperatures. However, in practice, a heat exchange between liquids at different temperatures and the liquid on one hand and test ring (including pump) on the other hand takes place. Due to the enormous heat capacity of the test rig, undesirable cooling or heating of the liquid takes place, whereby in the region of the pump, the sought temperature cannot be reached fast enough or only with great energy outlay for heating and cooling.

[0004] The conventional internal prior art of a test device for pumps is represented in Figure 2, and has the features described in the generic portion of the independent claim 1.

[0005] Against this background, it is the object of the present invention to permit a more efficient testing of pumps at temperatures .that change over time.

[0006] The object is achieved according to the invention by means of a device with the features of claim 1, as well as by a method with the features of Claim 14.

[0007] According to the invention, a test device for pumps, for alternate testing at an upper and a lower temperature, is provided. It is thus provided that, for testing of each pump, the temperature is changed at least once. Normally, a plurality of changes between the upper and the lower temperature are provided.

[0008] The test device comprises a first reservoir for a liquid at a first temperature and a second reservoir for a liquid at a second temperature. Typically, water is provided as liquid, in principle, however, other liquid come into consideration. The first and second temperature can correspond to the upper and lower temperature, however this is not inevitably the case. The reservoirs are liquid vessels, which can be insulated if appropriate. They can be connected to heating or cooling devices; furthermore, an expansion vessel and a safety valve can be provided in order to compensate for volume and pressure changes within the reservoir. Typically, venting is also provided.

[0009] A first distribution line emerges from the first reservoir and a first collection line leads to the first reservoir. That is to say that liquid can pass through the first distribution line from the first reservoir. Correspondingly, the first collection line is provided for allowing liquid to flow back into the first reservoir. In a corresponding manner, a second distribution line emerges from the second reservoir, and a second collection line leads to the second reservoir. The terms “emerge” and “lead to” relate to a provided flow direction of liquid within the aforementioned lines. Apart from this, they express the fact that the line in each case is connected to the aforementioned reservoir.

[0010] The test device further comprises a plurality of test units. The number thereof determines the maximum number of pumps that can be tested simultaneously. Herein, each test unit comprises a first feed line, which emerges from the first distribution line, a second feed line, which emerges from the second distribution line as well as a feed test line, into which the first and second feed lines unit. Overall, then, from the first (second) distribution line, a multiplicity of first (second) feed lines emerge, namely one per test. In the uniting of the lines, it is possible that the feed test line may not differ from at least one of the two feed lines as regards its cross-section and other design. In particular, the feed test line may be the continuation of the first feed line, that is to say may run in alignment therewith; in this case, simply that portion of the line that is located behind the unification point with that of the second feed line is termed the feed test line.

[0011] Furthermore, each test unit comprises a first return line, which leads to the first collection line, a second return line, which leads to the second collection line, and a return test line, which branches into the first and second return lines, it being possible to connect a pump to be tested between the feed test line and the return test line. Here, too, as described above, it is possible that the return test line is designed in a similar manner to one of the two return lines. Overall, a multiplicity of first (second) return lines lead to the first (second) collection line, namely one per test unit.

[0012] The feed test line and the return test line form the portion of the test unit that is provided for connection of the pump. That is to say an input of the pump is connected to the feed test line and an output of the pump to the return test line. In operation, the pump sucks this liquid via the feed test line and ejects it via the return test line. Each of the two lines can be designed to be very short, so that a connection provided for the pump is located in the direct vicinity of the branching point of the return lines or of the unit point of the feed lines. It goes without saying that the pump can, if appropriate, be connected, indirectly via additional adapter pieces or similar to the test line in each case. Furthermore, in each of the test lines, manual valves can be provided, by means of which they can be closed in the absence of a pump and/or for their removal or installation. The valves can be used to adjust the pressure point in a desired manner, to achieve the objective that the pump is operated within the characteristic curve.

[0013] Each test unit furthermore comprises a first valve arrangement, by means of which the first feed line and the second feed line can be alternatively closed and a second valve arrangement, by means of which the first return line and the second feed line can be alternately closed. “Alternately closable” here means that it is possible to close the first feed line and open the second, or vice versa. One could also talk of “closable in alternation with one another” or “closable in turn”. This can also include embodiments in which, in addition, both feed openings can be simultaneously opened or closed, which, however, is not necessary for the realization of the invention. The valve arrangements act according to the invention as directional control valves, via which the liquid stream is diverted.

[0014] Overall, the first distribution line, the first feed line, the feed test line, the return test line, the first return line as well as the first collection line form a circuit between the first reservoir and a pump to be tested. Correspondingly, the second distribution line, the second feed line, the feed test line, the return test line, the second return line as well as the second collection line form a circuit between the second reservoir and a pump to be tested. The two circuits only have the piece formed by the feed test line and the return test line in common. This piece can, as already been mentioned, be short in design. In each case, this only concerns a comparatively small portion of the entire test device.

[0015] By means of the first valve arrangement, it is possible to open the liquid replenishment from, in each case, precisely one of the two distribution lines and to block the replenishment from the other distribution line. In a similar manner, with the second valve arrangement, one of the two collection lines can be selected, into which a draining of liquid is possible. The liquid can thus be circulated in one of the two above-described circuits or in the other. The liquids circulating here “share” only the portion formed by the two test lines with one another. That is to say that portion of the test device that is directly exposed to drastically different temperatures is small. It has a comparatively small heat capacity and can be rapidly cooled or heated by means of liquid in its interior. Vice versa, it only extracts a relatively low heat quantity from the liquid or only dissipates a low heat quantity to it, so that the temperature of the liquid is changed by a relatively small amount.

[0016] It is therefore possible with the test device according to the invention, to rapidly complete the temperature exchange in the vicinity of the pump. The provided temperatures in the vicinity of the pump can be adjusted more precisely. Thereby the provided temperature profiles can be realized considerably more precisely than in the prior art. In the process, the heat transfer processes between the liquid and lines can be kept low. Large portions of the lines involved, in particular the distribution lines and the collection lines, as well as at least portions of the feed and return lines, always come into contact with liquid of approximately constant temperature.

[0017] The first valve arrangement can, in principle, by realized by means of an individual multi-directional valve, which is disposed at the uniting point of the first and second flow line. Such a valve can alternately produce a connection between the first feed line and feed test line or second feed line and feed test line.

According to a different, advantageous embodiment, the first valve arrangement comprises a first feed valve within the first feed line as well as a second feed valve within the second feed line. As in the prior art, normally pilot-operated valves, such as, for example, magnetic valves, pneumatically actuated ball cocks, slanted seat valves, diaphragm valves are used, which can the closed and opened by remote control. Inlet valves can be disposed in the vicinity of the uniting point, to prevent, for example, liquid at (approximately) the first temperature being located between the valve and uniting point after the closing of the first inlet valve, said liquid, in a manner that is difficult to predict mixing with the liquid, which is used in the subsequent interval and is (approximately) at the second temperature, and changes the temperature thereof.

[0018] The same applies to the second valve arrangement. This may be designed as a multi-directional valve, however advantageously also comprises a first return valve within the first return line, as well as a second return valve within the second return line.

[0019] Advantageously, the test device also comprises a temperature sensor disposed on the return test line, as well as a control device that is connected thereto. The connection can of course also be by cable or else wireless. It is only important that the control device can receive measurement values from the temperature sensor. By this means, the temperature behind the pump can be checked. If a temperature change has taken place in this range, this is an indication of the fact that it has also taken place within the pump. In particular, this gives information about whether, for example, during changeover from the first to the second temperature, the return test line has already been drained of liquid at the first temperature. For this purpose, it is preferred to install the temperature sense close to the branching point ot the first and second return line. Of course, an additional temperature sensor may be provided close to the pump.

[0020] As already described, the test lines form the only region of the line system that is through which liquid at alternating temperature inevitably flows. If the first valve arrangement is switched over, so that the second feed line is released, liquid at the first temperature is still located in the test lines. If the second return line is immediately released, this is to a certain extent “contaminated” with liquid at the first temperature. To avoid this, the control device is preferably set up for a temperature exchange, first to change over the first valve arrangement and only to change over the second valve arrangement at a preset temperature change on the temperature sensor. A corresponding temperature change, in the aforementioned example, shows that the test lines are at least largely emptied of liquid at the first temperature which is therefore forced into the first return line. The latter can thus be closed and the second return line opened.

[0021] Even with a test device according to the invention, an undesirable heat exchange between the liquid and lines cannot be entirely prevented. As a consequence of this, a cool liquid can be heated or a hot liquid can be cooled, on the way from the reservoir to the pump. To compensate for this effect, it is preferred that the control device is set up, by means of heat exchange means, to set a temperature in at least one reservoir that lies outside the interval provided by the upper and lower temperature. Heat exchange means includes all devices for heating or cooling, that is to say, for example, heat pumps, heat exchangers with circulating pumps, heating elements, etc., as well as associated sensors. The temperature control means are actuated such that, for example, the first temperature sill lies above the upper temperature and/or the second temperature below the lower temperature (or vice versa). That is to say the liquid in at least one reservoir is overheated or undercooled with respect to the sought temperature profile. By this means, the above-described cooling and heating effects can be effectively compensated. Herein, it can be provided that the control device automatically determines the values for the first and second temperature from the provided values for the upper and lower temperature.

[0022] The embodiments of the invention that were discussed above are “symmetrical with respect to the first and second reservoir and the lines that are assigned thereto. Below, the embodiments are discussed that differ with respect to the two reservoirs or line systems. These embodiments are in particular seen as advantageous if the first temperature is the “hot" temperature and the second temperature is the “cool” temperature. The liquid at the first temperature can here be described as the hot liquid and the liquid at the second temperature can here be described as the cold liquid. This thus refers to the fact that the first temperature is above the second temperature. In addition, the converse case is also conceivable.

[0023] In particular, if the liquid from the second reservoir is only used for comparatively short time intervals, but also in other cases it may be advantageous if a circuit between the pump and reservoir is not continually maintained between the pump and reservoir. That is to say that liquid present in the lines may be sufficient to maintain the desired temperature. In this case, according to a preferred embodiment of the invention, a short-circuit can be produced outside the second reservoir between the second distribution line and the second collection line. That means that a connection can be produced between the aforementioned lines already upstream of the reservoir - seen from the test unit.

[0024] The aforementioned connection can be achieved by an additional line, which connects the second distribution line and the second collection line, and is opened via valves as required. Preferably, however, a four-way valve is used, by means of which the short-circuit can be produced. By this means the distribution line and the collection lien are in each case subdivided into two sections , which in each case run together at the four-way valve. In one setting of the valve, a liquid path between the two sections of a line is opened; in the other setting (corresponding to the short-circuit), a liquid path is provided, first between the sections of the two lines that are close to the reservoir and second between the sections that are remote from the reservoir.

[0025] A short circuit can be effectively controlled by means of an already described control device, to which a temperature sensor disposed on the return test line is connected. This is therein set up, for a preset approximation of the temperature of the temperature sensor to the second temperature, to produce the short-circuit and to cancel the sort circuit for a given deviation. That is to say when the temperature in the return test line (which is downstream of the pump) has approached the second temperature (the temperature in the second reservoir) up to a given value, this is evaluated as a sign that no feeding from the second reservoir is necessary any longer and the liquid connection to the second reservoir is interrupted by the short circuit. That is to say when the temperature in the return test line (which is downstream of the pump) has approached the second temperature (the temperature in the second reservoir) up to a given value, this is evaluated as a sign that no feeding from the second reservoir is necessary any longer and the liquid connection to the second reservoir is interrupted by the short circuit.

[0026] A typical example of a test cycle consists in a sequence of longer time intervals in which the pump is heated to the upper temperature, as well as shorter intervals in which the pump is cooled to the lower temperature. For such cases, the control device is preferably set up for a time sequence in which, during relatively long time intervals, liquid is used from the first reservoir and during relatively short intervals, liquid is used from the second reservoir. The liquid “from the second reservoir” can here also be liquid that, because of the short-circuit that is cause be repeatedly circulated with the exclusion of the second reservoir, but primarily originates therefrom.. The first reservoir can herein, in particular be the "hotter” reservoir; however the converse case, corresponding to a different test cycle, is also conceivable.

[0027] In particular if the liquid at the second temperature, during the test cycle, is only provided briefly for use, that is to say mainly the liquid at the first temperature is used, it may be advantageous to keep the heat capacity of those lines low that only transport the liquid coming from the second reservoir. This can be achieved by a reduction of the cross-section. By this means, the mass of the respective line and thus the heat capacity decreases; the same applies to its (cross-section-dependent) thermal conductivity. In an advantageous embodiment of the invention, the first distribution line, the first collection line, the first feed line and the first return line have at least partly a larger cross-section than the second distribution line, the second collection line, the second feed line and the second return line.. Thus, for example, the first feed line (or return line) can have a larger cross-section than the second feed line (or return line).

[0028] Usually, at least the cross-section of the first feed line and first return line will correspond with one another, likewise the cross-section of the second feed line and second return line. The mutually corresponding collection lines and distribution lines also normally have the same cross-section. However, it is possible that the cross-section of a collection line (which is fed by a plurality of feed lines) is larger than the feed line that is thereby connected.

[0029] To ensure the greatest possible flexibility regarding the number of pumps to be tested and the beginning and time profile of the individual test procedures, it is preferable if the valve arrangements can be connected independently of one another in different test units. That is to say a switch connected therewith permits, for example, the first feed line in one test unit to be opened while the first feed line in a different test unit remains, or is, closed. Correspondingly, a control device should of course be designed such that the valves in the individual test units can be individually actuated.

[0030] The object of the invention is, furthermore, a method for testing pumps. This is performed in a device already describe above. This comprises a first reservoir, a second reservoir, a first distribution line, which emerges from the first reservoir, a first collection line, which leads to the first reservoir, a second distribution line, which emerges from the second reservoir, a second collection which leads to the second reservoir, as well as a plurality of test units. Each test unit comprises a first feed unit, which emerges from the first distribution line, a second feed line, which emerges from the second distribution line, a feed test line, at which the first and second feed line unit, a first return line, which leads to the first collection line, a second return line, which leads to the second collection line, a return test line, which branches into the first and second return line, a first valve arrangement, by means of which the first feed line and the second feed line can be alternately closed, and a second valve arrangement, by means of which the first return line and the second feed line can be alternately closed..

[0031] According to the method, in the first reservoir a liquid at a first temperature is stored and in the second reservoir, a liquid at a second temperature is stored. Between the feed test line and the return test line of at least one test unit, a pump to be tested is connected. The pump is operated and, by changing over the first and second valve arrangement, liquid is supplied from the first and second reservoir alternately in time to the pump.

[0032] The preferred embodiments of the method according to the invention correspond to those of the device according to the invention. They are therefore not explained again in detail. Insofar as reference is made to a control device and a temperature sensor, however, the corresponding process steps can also take place independently of thereof. It goes without saying, however, than an efficient, repeatable test sequence makes the use of a control device as well as suitable sensors, which are connected thereto, virtually essential.

[0033] It is thus preferred in the process that, for a temperature exchange, first the valve arrangement is switched over and only with a predetermined temperature in the return test line, the second valve arrangement is switched over.

[0034] It is also advantageous if, by means of temperature exchange means in at least one reservoir, a temperature is set, which lies outside the intervals determined by the upper and lower temperature.

[0035] During the process, preferably at least occasionally between the second distribution line and the second collection line, a short-circuit can be produced outside the second reservoir. This can be produced, in particular, by means of a four-way valve.

[0036] Preferably, the short-circuit is therein produced for a predetermined approximation of the temperature in the return test line to the second temperature and is cancelled for a predetermined deviation from the second temperature of the short-circuit [0037] It is furthermore preferred, in time succession, during relatively long time intervals, to access liquid from the first reservoir and during shorter time intervals to access liquid from the second reservoir.

[0038] The valve arrangements in different test units are preferably switched independently of one another.

[0039] Details of the invention are subsequently explained with the aid of an exemplary embodiment with reference to the figures, wherein

Figure 1 shows a diagrammatic view of a test device according to the invention, and

Figure 2 shows a diagrammatic view of a conventional test device according to the prior art, which does not fall within the scope of the claims.

[0040] Figure 1 shows a test device 1, with which the quality of pumps 50, for example circulation pumps for heating systems, is tested. It is provided that, herein, if appropriate, a plurality of pumps 50 can be simultaneously tested. The provided test cycle comprises intervals of 45 minutes, during which the pump 50 is intended to operate at an upper temperature of 90°C, as well as intermediate intervals of 15 minutes, during which a temperature of 50°C is provided.

[0041] In order to be able to test the pump 50 at the temperatures in each case, two reservoirs 2, 3 are provided, specifically a hot-water reservoir 2 and a cold water reservoir 3. The hot water reservoir 2 is filled with water, which is kept at a temperature of approximately 95°C. By means of this overheating with respect to the test temperature of 90°C, undesirable cooling effects on the way to the pump 50 are compensated. The hot water reservoir 2 is heated via a screw-in heating element 8 disposed in its wall. An expansion vessel 9 is connected to the hot-water reservoir 2 in order to compensate volume and pressure changes. A relief valve 10 is also connected to the expansion vessel 9. The hot-water reservoir 2 furthermore has a vent 6 as well as a manual valve 7, via which the reservoir 2 can be filled or emptied. For monitoring the most important operating parameters pressure and temperature, a thermometer 4 and a pressure gauge 5 are provided.

[0042] The cold water reservoir 3 is filled with water with a temperature of approximately 35°C. This temperature is in turn below the test temperature of 50°C to compensate for heating effects. The term “cold water” is of course relative here, and means that this is the colder water in comparison to the hot water reservoir 2. To the cold water reservoir 3, essentially the same elements are connected as to the hot-water reservoir 2, with the exception of the screw-in heating elements 8. The latter could be optionally provided in order to prevent the temperature significantly falling below the provided value. If the temperature rises significantly above 35°C, the water can be guided past a heat exchanger 12 by means of a circulating pump 11, whereby a cooling takes place. The inflow to the heat exchanger 12 can, if necessary, be opened and closed by means of two manual valves 13,14, but also via automatic valves.

[0043] Temperature and pressure in the reservoirs 2, 3 are monitored from a central control device (not illustrated), which, on demand, actuates the circulation pump 11 or the screw-in radiator 8.

[0044] From the hot-water reservoir 2, a first distribution line 20 emerges. A first collection line 21 leads back to the hot water reservoir 2. These lines, to a certain extent, form the backbone of a water circuit between the hot-water reservoir 2 and the pumps 50. In a corresponding manner, a second distribution line 22 and a second collection line 23 are connected to the cold-water reservoir 3. Flowever, the second distribution line 22 and the second collection line 23 are guided via a four-way valve 24, whereby the second distribution line 22 is subdivided into a first and second section 22.1, 22.2. Correspondingly, the second collection line 23 is subdivided into a first and second section 23.1, 23.2. The function of the four-way valve 24 is further explained below.

[0045] The test device 1, comprises five test units 30. The later are designed in a similar manner, therefore only one test unit 30 is discussed below. Of course, the system can be extended to cover a substantially larger number oftest units 30.

[0046] From the first distribution line 20, there emerges a first feed line 31 of the test unit 30; correspondingly, a second feed line 32 emerges from the second distribution line 22. These feed lines 31, 32 are provided for feeding hot or cold water into the test unit 30. The can be closed via a first feed valve 37 or a second feed valve 38 respectively. The first feed line 31 and the second feed line 38 unite to form a feed test line 33, which is provided for connecting the pump 50 to be tested. For the installation or removal of the pump 50, the feed test line 33 can be closed by means of a manual valve 42. The pump 50 is furthermore connected to a return test line 36, which in a corresponding manner can be closed by means of a manual valve 43. The return test line 36 branches into a first return line 34, which leads to the first collection line 21, as well as a second return line 35, which leads to the second collection line 23. The first return line 34 has a first return valve 39. Correspondingly, the second return line 35 can be closed by means of a second return valve 40. The first and second feed valve 37, 38 as well as the first and second return valve 39, 40 are connected to the central control device and are controlled thereby. Of course, the valve 37, 38, 39, 40 are controllable independently of one another in different test units 30.

[0047] For the illustrated embodiment, the feed test line 33 is essentially an extension of the first feed line 31, that is to say it has the same cross-section and is aligned at the transition point to the first feed line 31 The second feed line 32 joins at an angle and moreover has a smaller cross-section. In a corresponding manner, the first return line 34 essentially forms an extension of the return test line 36, while the branching second return line 35 has a smaller cross-section by comparison. The purpose of the smaller cross-section is to reduce the heat capacity and thermal conductivity of the corresponding line portions. They thus extract less heat from the lines that are part of the hot water circuit, which is relevant since the test cycle is predominantly operated with hot water.

[0048] Overall, five first feed lines 31 emerge from the first distribution line 20 and five second feed lines 32 emerge from the second distribution line 22. Correspondingly, five first return lines 34 lead to the first collection line 21 and five second return lines 35 lead to the second collection line 23.

[0049] The operation of the test device 1 is explained below. At the beginning of a provided test cycle, an interval with the upper temperature of 90°C is provided. In this case, the first feed valve 37 and the first return valve 39 are opened, while the second feed valve 38 and the second return valve 40 are closed. Of course, the manual valves 42,43 are opened. The pump 50 to be tested, which is typically electrically operated, is switched on and, via the feed test line 33, the first feed line 31 and the first distribution line 20 suck water out of the hot-water reservoir 2. Via the return test line 36, the first return line 34 and the first collection line 21, the water is conveyed back to the hot-water reservoir 2. Thereby, the control device controls the temperature prevailing there via a temperature sensor 41 that is disposed in the return test line 36.

[0050] After the end of the provided time interval of 45 minutes, the control device closes the first feed valve 37 and opens the second feed valve 38. The switch state of the return valves 39, 40 remains unchanged for the time being. The pump, via the feed test line 33, the second feed line 32 and the second distribution line 22, then sucks in cold water. Within the test lines 33,36, however, there is still hot water, which could lead to undesirable contamination of the cold water circuit. To prevent this, the control device further monitors, via the temperature sensor 41, the temperature in the return test line 36. As soon as the temperature there falls below a particular value (for example, 55 °C), this is evaluated as a sign that cold water at least predominantly flows through the return test line 36, the pump 50 and the feed test line 33, and that the hot water residues there have thus been forced out via the first return line 34. The control device thereupon closes the first return valve 39 and opens the second return valve 40. The test cycle is then continued using cold water.

[0051] The control device continues to monitor, via the temperature sensor 41, the temperature in the return test line 36. If it is ascertained that the registered temperature within a predetermined interval, for example 5°C, lies at about the provided lower temperature of 50°C, the control device controls the four-way valve 24 such that the second section 22.2 of the second distribution line 22 is connected to the second section 23.2 of the second collection line 23. The aforementioned section 22.2,23.2 are thus to a certain extent short-circuited. The direct cold-water feed from the cold water reservoir 3 is thus occasionally interrupted. If the control device registers via the temperature sensor 41 that the temperature deviates too strongly from the provided lower temperature, the fourway valve 2.4 controls it such that the first and second section 22.1,22.2 of the second distribution line 22 are connected to one another as are the first and second sections 23.1,23.2 of the second collection line 23.

[0052] After completion of the provided time interval of 15 minutes, the hot water feed is switched over again. To this end the control device closes the second feed valve 38 and opens the first feed valve 37. Via the temperature sensor 41, the temperature in the return test line 36 is monitored and the second return valve 40 is only closed when a certain temperature (for example, 80°C) is exceeded, and the first return valve 39 is opened.

[0053] At the illustrated test device 1, only the pump 50 and the adjacent test liens 33, 36 are thus subjected to strongly changing temperatures. By contrast, the first distribution line 22, the first feed line 31, the first return line 34 and the first collection line 21 of the hot water circuit are kept almost constantly at one temperature. The same applies for the corresponding lines 22, 23, 32, 35 of the cold water circuit. Undesirable heat-transfer effects between the lines and liquid are thus reduced to a necessary minimum. Provided temperatures in the region of the pump can therefore be rapidly and precisely reached and, furthermore, energy for heating and/or cooling can be saved.

[0054] In the present case, the test operation was described for an individual pump 50. The illustrated test device 1, however, is designed for testing a plurality of pumps 50 simultaneously according to a synchronous test cycle, or else to subject a plurality of pumps 50 to time-staggered test cycles. With respect to the switch state of the four-way valve 24, it is thereby provided that a short-circuit is only produced when the temperature sensor 41, in all the test units 30 that are in operation, registers a temperature that, in the above-described interval, lies at about the provided lower temperature.

[0055] The advantages of the invention are again made clear by comparison with a conventional test device 101 shown in Figure 2. The embodiment of the hot-water reservoir 2, of the cold-water reservoir 3 as well as of the components disposed thereon for temperature and pressure monitoring do not differ from the above described tst device 1 according to the invention, for which reason this is not explained again.

[0056] The hot water reservoir 2 is connected via a first distribution valve 108 to a distribution line 102, as well as via a first collection valve 109 to a collection iine 103. The cold water reservoir 3 is correspondingly connected via a second distribution valve 110 to the same distribution line 102, as well as via a second collection valve 111 to the same collection line 103. From the distribution line 102, there emerge a plurality of feed lines 104, which in each case can be blocked via hand valves 106. An equal number of return lines 105, which can also be closed via hand valves 107, leads to the collection line 103. Between a feed line 104 and a return line 105, a pump 50 to be tested is in each case connected.

[0057] Tor a test with hot water, the first distribution valve 108 and the first collection valve 109 are opened and the second distribution valve 110 as well as the second collection valve 111 are connected. All the connected pumps 50 then suck in hot water via their respective feed line 104 and the distribution line 102 and expel it again via the return lines 105 and the collection line 103. Tor a test with cold water, the first distribution valve 108 and the second collection valve 109 are connected and the second distribution valve 110 as well as the second collection valve 111 are opened. The pumps 50 in each case then suck in cold water via their respective feed line 104 and the distribution line 102 and expel it again via the return lines 105 and the collection line 103. First, hot water that is initially still in the lines 102, 103, 104 and 105 thereby leads to a considerable thermal contamination of the cold water; second, all lines 102,103,104 and 105 must be cooled down from the upper temperature to the lower temperature. With the change from cold water to hot water, the lines must be correspondingly heated again.

[0058] The system as a whole is therefore sluggish and a lot of energy is lot due to undesirable heat transfers between the liquid and lines. In addition, all the pumps 50 used must inevitably be subjected to a synchronous test cycle. The setting of individual pumps is not possible. By contrast, the test device 1 shown in Fig. 1 is efficient, versatile and can go through a provided temperature profile rapidly and with great precision.

List of Reference Characters [0059] 1,101 Test device 2 Hot-water reservoir 3 Cold-water reservoir 4 Thermometer 5 Pressure gauge 6 Venting 7,13, 14,42,43, 106, Manual valve 107 8 Screw-in heating element 9 Expansion vessel 10 Relief valve 11 Circulation pump 12 Heat exchanger 20 First distribution line 21 First collection line 22 Second distribution line 22.1.23.1 First section 22.2.23.2 Second section 23 Second collection line 24 Four-way valve 30 Test unit 31 First feed line 32 Second feed line 33 Feed test line 34 First return line 35 Second return line 36 Return test line 37 First feed valve 38 Second feed valve 39 First return valve 40 Second return valve 41 Temperature sensor 50 Pump 102 Distribution line 103 Collection line 104 Feed line 105 Return line 108 First distribution valve 109 First collection valve 110 Second distribution valve 111 Second collection valve

Claims (14)

1. Test device (1) for pumps (50), for alternate testing at an upper temperature and a lower temperature and with - a first reservoir (2) for a liquid with a first temperature, - a second reservoir (3) for a liquid with a second temperature, - a first distribution line (20) emanating from the first reservoir (2), - a first assembly line (21) leading to the first reservoir, - a second distribution line (22) emanating from it a second reservoir (3), - a second assembly line (23) leading to the second reservoir (3), and - a plurality of sample units (30), each sample unit (30) being characterized by - a first supply line (31), starting from the first distribution line (20), - a second supply line (32), starting from the second distribution line (22), - a flow test line (33) to which the first (31) and second supply line (32) are connected, - a first return line (34) leading to the first bus line (21), - a second t - a reverse test line (35) leading to the second bus line (23), - a return test line (36) which is branched in the first (34) and second return line (35) and in which between the flow test line (33) and the reflux test line (36) may be connected to a pump (50) to be tested - a first valve arrangement (37, 38) by means of which the first supply line (31) and the second supply line (32) may alternatively be closed, and - a second valve arrangement (39, 40), by means of which the first reflux conduit (34) and the second reflux conduit (35) can alternatively be closed. Test device according to claim 1, characterized in that the first valve arrangement (37, 38) comprises a first five flow valve (37) within the first flow line (31) and a second flow valve (38) within the second flow line (32). . Test device according to claim 1, characterized in that the second valve arrangement (39, 40) comprises a first reflux valve (39) within the first reflux line (34) and a second reflux valve (40) within the second reflux line (35). Test device according to one of the preceding claims, characterized by a temperature sensor (41) arranged by the return line (36) and a control device associated with it. Test device according to claim 4, characterized in that the control device is arranged to be able to change the temperature, - then to adjust the first valve arrangement (37, 38) and - only to be able to adjust the temperature sensor (41) in advance. second valve arrangement (39, 40). Test device according to one of the preceding claims, characterized in that the control device is arranged to - by means of tempering means (8, 11, 12) in the at least one reservoir (2, 39) - be able to adjust to a temperature which is at outside the range given by the upper temperature and lower temperature. Test device according to one of the preceding claims, characterized in that the first temperature is above the second temperature. Test device according to one of the preceding claims, characterized in that a short circuit can be provided outside the second reservoir (3) between the second distribution line (22) and the second connecting line (23), and / or a distribution circuit (20) and the first connecting line (21) may be provided a short circuit outside the first reservoir (2). Test device according to claim 8, characterized by a four-way valve (24), by means of which a short circuit can be provided. Test device according to claim 8 or 9, characterized by a temperature sensor (41) arranged by the reflux test line (36) and an associated control device, which is adapted to be able to approximate the temperature sensor (41) temperature to the other temperature in advance. provide a short circuit and, in the event of a deviation already given, be able to cancel the short circuit. Test device according to one of the preceding claims, characterized in that the control device is arranged for a time sequence in which liquid is used for the first reservoir (2) for a longer period of time and liquid for the second reservoir (3) is used for a shorter time interval. ). Test device according to one of the preceding claims, characterized in that the first distribution line (20), the first assembly line (21), the first flow line (31) and the first return line (34) have at least partially a larger cross-section than the second distribution line (22), the second assembly line (23), the second supply line (32) and the second return line (35). Test device according to one of the preceding claims, characterized in that the valve devices (37, 38, 39, 40) can be connected independently of one another in different test units (30). A method for testing pumps in an apparatus with - a first reservoir (2), - a second reservoir (3), - a first distribution line (20) starting from the first reservoir (2), - a first assembly line ( 21) leading to the first reservoir (2), - a second distribution line (22) forming from the second reservoir (3), - a second assembly line (23) leading to the second reservoir (3), - a plurality of sample units (30), each sample unit (30) being characterized by - a first supply line (31) starting from the first distribution line (20), - a second supply line (32) starting from the second distribution line (22) ), - a flow test line (33) which is joined by the first (31) and second flow line (32), - a first return line (34) leading to the first assembly line (21), - a second return line (35) leading to the second assembly line (23) - a reflux test line (36) which branches into it. a pump (50) to be tested, - a first valve device (37, 38), by means of a first valve device (37, 38), which can be connected between the flow test line (33) and the reflux test line (36). from which the first flow line (31) and the second flow line (32) can alternatively be locked, - a second valve device (39, 40), by means of which the first return line (34) and the second flow line (35) can alternatively be locked, and wherein - in the first reservoir (2) a liquid having a first temperature is stored, and - in the second reservoir (3) a liquid having a second temperature is stored, - between the flow test line (33) and the reflux test line (36) belonging to at least one test unit (30) is connected to a pump (50) to be tested, - that the pump (50) can be operated, and - where by switching the first (37, 38) and second valve device (39, 40) in the sample unit (30) for alternating periods of time, to the pump ten Liquid is supplied from the first reservoir (2) and the second reservoir (3).