Powder thin-flow pump

Description

[0001] The invention relates to a thin-phase powder pump for conveying coating powder from a powder reservoir to a powder spraying device, wherein the thin-phase powder pump has a powder inlet which is fluidly connected or connectable to the powder reservoir, and a powder outlet which is fluidly connected or connectable to the powder spraying device, and wherein the thin-phase powder pump has a powder conveying injector with a drive nozzle and a collecting nozzle.

[0002] In powder coating technology, it is well known to use powder feed injectors to convey coating powder. These injectors utilize the so-called Venturi effect with the aid of conveying air to convey, in particular, fluidized coating powder from a powder reservoir (powder storage container) and feed it through the collecting nozzle via, for example, a powder feed hose to a powder spray device, for example, in the form of a coating gun. The collecting nozzle, usually designed as an elongated hollow body, forms a so-called jet collecting channel inside it, into which the powder-air mixture to be conveyed is introduced.

[0003] Opposite the jet catcher channel of the catcher nozzle, upstream in the axial direction, is a propulsion or conveying jet nozzle, through which propulsion or conveying air is forced into the catcher nozzle. Due to the relatively small diameter of the propulsion or conveying jet nozzle, a high-velocity air flow is generated, creating a negative pressure in an immediately adjacent powder feed channel, which is fluidly connected to the powder reservoir. Due to this negative pressure, the usually fluidized coating powder is forced from the powder reservoir (powder storage container) to the powder feed channel toward the catcher nozzle, through which it is fed to the powder feed hose.

[0004] A powder feed injector of this type with a corresponding Venturi nozzle arrangement is known, for example, from German patent application DE 198 24 802 A1. Other known powder feed injectors are described in DE 44 05 640 A1 and EP 0 423 850 A2.

[0005] Powder feed injectors known from the prior art have the disadvantage that the air flow and the powder particles wear out the drive nozzle and the collecting nozzle, and in particular the jet catching channel of the collecting nozzle. Due to the abrasive effect of the coating powder, which is conveyed through the collecting nozzle at high speed, the jet catching channel of the collecting nozzle in particular is subject to relatively high wear, which is generally noticeable in the fact that the material removal leads to a widening of the jet catching channel, which causes a drop in pressure. As a result, over time more and more drive or conveying air is required to convey the coating powder. This is not only uneconomical but can also lead to unsatisfactory coating results due to uneven coating powder clouds, or the amount of powder to be conveyed can decrease over time.

[0006] For this reason, it is necessary to regularly replace the catching nozzle in powder feed injectors. Alternatively or additionally, it is known, for example from DE 198 24 802 A1, to form the jet catching channel of the catching nozzle from a relatively hard material, particularly a glass-like material.

[0007] The present invention is based on the problem that in practical operation of a thin-phase powder pump with a powder feed injector, it is often not possible for the operator of the thin-phase powder pump to recognize when the right time to replace the collector nozzle of the powder feed injector has arrived. This is because in practical operation it is common practice to visually observe the coating powder cloud directed onto an object to be coated and, based on this visual observation, to adjust the pressures of the conveying air and the additional air accordingly so that the total powder quantity delivered by the thin-phase powder pump does not fall below a desired minimum value. The collector nozzle of the powder feed injector is generally only replaced when the desired minimum powder quantity can no longer be achieved in the powder spray device by appropriately adjusting the pressures of the conveying air and the additional air.However, this point in time is significantly later than the point in time when, from an economic point of view and with regard to an optimal coating result, replacing the collecting nozzle is actually recommended.

[0008] Based on this problem, the present invention is based on the object of developing a thin-phase powder pump of the type mentioned at the outset in such a way that it can be used as economically as possible even without lengthy experience on the part of the operator, while at the same time an optimal coating result and in particular uniform coating powder clouds can be achieved in the powder spraying device which is fluidly connected to the thin-phase powder pump.

[0009] This object is achieved according to the invention by the subject matter of independent patent claim 1, wherein advantageous further developments thereof are specified in the corresponding dependent claims.

[0010] Accordingly, in particular, a thin-phase powder pump is proposed for conveying coating powder from a powder reservoir to a powder spraying device. The thin-phase powder pump has a powder inlet that is fluidly connected or connectable to the powder reservoir, and a powder outlet that is fluidly connected or connectable to the powder spraying device. The thin-phase powder pump according to the invention has a powder conveying injector with a drive nozzle and a collecting nozzle. According to the invention, it is particularly provided that the thin-phase powder pump further has a valve device in order to be able to selectively interrupt a fluid connection between the powder inlet of the thin-phase powder pump and a powder inlet of the drive nozzle.

[0011] According to the thin-phase powder pump according to the invention, the valve device has a pneumatically actuated pinch valve which is provided in the flow path between the powder inlet of the thin-phase powder pump and the powder inlet of the drive nozzle.

[0012] The provision of a valve device for selectively interrupting the flow connection between the powder inlet of the thin-phase powder pump and the powder inlet of the drive nozzle offers various advantages, such as simplified and particularly efficient cleaning of the thin-phase powder pump or the powder feed injector, for example, during a powder change. For this purpose, the valve device can be used to interrupt the flow path between the powder inlet of the thin-phase powder pump and the powder inlet of the drive nozzle, allowing the conveying air and / or the additional air orAdditional air can be used as purge air to clean the components of the powder feed injector and the components arranged downstream of the powder feed injector, in particular the powder outlet of the thin-phase powder pump, a powder hose connected to the powder outlet of the thin-phase powder pump and / or a powder spray device fluidly connected to the outlet of the thin-phase powder pump.

[0013] According to the thin-phase powder pump according to the invention, it further comprises a compressed air inlet device which opens at least one point into the flow connection between the powder inlet of the thin-phase powder pump and the powder inlet of the drive nozzle, wherein the compressed air inlet device serves to supply compressed air as flushing air as required and in particular for cleaning / flushing the powder feed injector or components provided downstream of the powder feed injector.

[0014] In a powder feed mode of the thin-phase powder pump, however, additional compressed air can be fed as additional transport compressed air into the flow connection between the powder inlet of the thin-phase powder pump and the powder inlet of the drive nozzle via the compressed air inlet device, as required.

[0015] According to the thin-phase powder pump according to the invention, the compressed air inlet device opens into the flow connection at a point between the valve device and the powder inlet of the drive nozzle. This embodiment offers the particular advantage of allowing automatic functional testing of the thin-phase powder pump.

[0016] For example, it is conceivable that the compressed air inlet device is assigned a filter which is permeable to air but not to coating powder, wherein at least one pressure sensor is connected to a compressed air path which extends from a compressed air line assigned to the compressed air inlet device to the air side of the filter, wherein the air side is separated by the filter from the flow connection between the powder inlet of the thin-phase powder pump and the powder inlet of the drive nozzle.

[0017] By providing such a pressure sensor, which should generally be designed to detect a static and / or dynamic pressure in an area in the flow connection between the powder inlet of the thin-phase powder pump and the powder inlet of the drive nozzle, it is possible to automatically detect the wear or degree of wear of the catching nozzle with the aid of a corresponding device for functional testing or an evaluation device associated therewith.

[0018] In particular, an evaluation device is used for this purpose which is designed to determine the wear or degree of wear of the collecting nozzle on the basis of a pressure value detected by the pressure sensor and on the basis of a quantity of conveying air supplied to the powder conveying injector per unit of time and / or a quantity of additional air supplied to the powder conveying injector per unit of time.

[0019] In this context, it is particularly conceivable to actuate the valve device for this purpose, interrupting the flow path between the powder inlet of the thin-phase powder pump and the powder inlet of the drive nozzle. This maximizes the amount of conveying air and supplementary air supplied to the powder feed injector per unit of time, and measures the resulting negative pressure via the pressure sensor. The measured pressure value is directly related to the degree of wear (diameter) of the catching nozzle.

[0020] In preferred implementations of the solution according to the invention, the thin-phase powder pump has a conveying air inlet associated with the powder conveying injector for supplying conveying air to the drive nozzle of the powder conveying injector, and an additional air inlet associated with the powder conveying injector for supplying additional air into the flow path of a powder-conveying air mixture at the powder outlet of the thin-phase powder pump. Furthermore, at least one conveying air adjustment element is preferably provided for adjusting the amount of conveying air supplied to the conveying air inlet per unit of time and / or for adjusting the amount of additional air supplied to the additional air inlet per unit of time.

[0021] The conveying air adjustment element includes, for example, a corresponding throttle device to precisely adjust the corresponding compressed air flows, either in fine, small steps or continuously. The most precise and optimal adjustment of the amount of conveying air supplied to the conveying air inlet per unit of time and the amount of additional air supplied to the supplementary air inlet per unit of time is crucial for achieving good coating qualities and achieving a high level of efficiency with regard to the required amount of coating powder.

[0022] The throttle device can, for example, comprise a corresponding throttle valve and a controllable electric motor with a motor shaft for adjusting the throttle valve. The motor can be any type of motor whose motor shaft can be controlled to defined rotational angle positions. It is preferably an electric stepper motor.

[0023] In this context, it is advantageous if, with the aid of the compressed air adjustment element, not only a quantity of compressed air supplied to the conveying air inlet or the additional air inlet per unit of time can be set, but also the corresponding actual value of the compressed air rate supplied to the conveying air inlet or the additional air inlet can be determined, in particular recorded.

[0024] According to embodiments of the powder thin-phase pump according to the invention, the aforementioned evaluation device of the device for functional testing is not only designed to detect the wear or degree of wear of the collecting nozzle of the powder feed injector, but also to detect at least one and preferably all of the following situations: an at least partial blockage at the powder outlet of the dilute phase powder pump; an at least partial blockage at the powder inlet of the dilute phase powder pump; and a lack of coating powder in the powder reservoir fluidly connected to the powder inlet of the dilute phase powder pump.

[0025] The evaluation device detects at least one of these situations, in particular taking into account the pressure value detected by the at least one pressure sensor and taking into account an actual value of a quantity of conveying air supplied to the conveying air inlet per unit of time and based on an actual value of a quantity of additional air supplied to the additional air inlet.

[0026] According to further developments of the thin-phase powder pump according to the invention, at least one powder rate actual value sensor is further provided, which is arranged in or near the powder feed injector at or in the flow path of the powder-conveying air mixture at the powder outlet of the thin-phase powder pump and serves to detect a corresponding actual value of a powder rate delivered by the powder feed injector. The detected actual value is preferably also evaluated accordingly by the evaluation device, in particular taking into account an actual value of the quantity of conveying air supplied to the conveying air inlet per unit of time and an actual value of the quantity of additional air supplied to the additional air inlet per unit of time.

[0027] In this way, it is particularly possible, preferably automatically and even more preferably optionally automatically, to set the actual value of the quantity of conveying air supplied to the conveying air inlet per unit of time and / or the actual value of the quantity of additional air supplied to the additional air inlet per unit of time such that the actual value of the powder rate at the powder outlet of the thin-phase powder pump does not exceed a predetermined or definable minimum value and does not exceed a predetermined or definable maximum value.

[0028] According to a further development of the solution according to the invention, a storage device is assigned to the evaluation device of the thin-phase powder pump, in which storage device, for different powder hoses fluidically connected to the powder outlet of the thin-phase powder pump, in particular for fixed values ​​of the quantity of conveying air supplied per unit of time to the conveying air inlet of the powder conveying injector and the quantity of additional air supplied per unit of time to the additional air inlet of the powder conveying injector, corresponding target values ​​of a static pressure are stored in an area in the fluid connection between the valve device and the powder inlet of the drive nozzle.

[0029] In this embodiment, it is possible for the evaluation device to record the parameters of a powder hose that is actually fluidically connected to the powder outlet of the thin-phase powder pump, and in particular its length and / or its flow resistance, by recording an actual value of the static pressure in the area in the fluid connection between the valve device and the powder inlet of the drive nozzle at the specified values ​​of the quantity of conveying air supplied to the conveying air inlet per unit of time and the quantity of additional air supplied to the additional air inlet per unit of time and comparing this with the corresponding setpoint values ​​stored in the memory device.

[0030] An exemplary embodiment of the thin-phase powder pump according to the invention is described in more detail below with reference to the accompanying drawings.

[0031] Exemplary embodiments of the invention are described in more detail below with reference to the accompanying drawings.

[0032] They show: FIG 1 schematically shows in a sectional view an exemplary embodiment of the powder thin-phase pump according to the invention; FIG 2 schematically shows in a sectional view a powder feed injector of the powder thin-phase pump according to FIG. 1 in a dismantled state; FIG 3 schematically in a sectional view of the powder feed injector according to FIG. 2 in its state installed in a housing of the thin-phase powder pump; and FIG 4 schematically shows a sectional view of another exemplary embodiment of the thin-phase powder pump not according to the invention.

[0033] To convey powder, especially coating powder, from a powder reservoir (for example in the form of a container or powder hopper) to a spray device, such as a spray gun, a jet pump with a powder feed injector is usually used. This jet pump operates according to the injector or Venturi tube principle. In this powder feed injector, an air jet creates a vacuum in a vacuum region formed by channel widening. This vacuum is used to extract powder, such as coating powder, from the powder reservoir. The extracted powder is entrained by the air jet and conveyed to the spray device. By adjusting the flow rate of the air stream, the vacuum and thus the amount of powder conveyed can be adjusted.

[0034] To achieve a constant flow rate of the powder-air mixture downstream of the powder outlet of the powder feed injector, the air velocity in the fluid lines, especially in the powder feed hoses, must be approximately 10 to 15 m / sec. At lower air velocities in the fluid lines, powder feed becomes uneven; pulsation of the powder-air mixture occurs, which propagates to the powder outlet at the powder spray device. At higher air velocities, the electrostatic application of the coating powder to the object to be coated is severely impaired because there is a risk that the powder already deposited on the object will be blown away.

[0035] Depending on the requirements of the coating process, the amount of powder fed to the powder spray device is increased or decreased. A practical value for the amount of powder fed per unit of time is approximately 300 g / min. If the amount of powder fed per unit of time needs to be reduced, the first step is to reduce the pressure of the conveying air supplied to the powder feed injector. This also reduces the flow rate of the conveying air in the fluid lines. However, the total air flow must neither be too low nor exceed a maximum value. To compensate for this reduction in air flow, i.e., to return to an air velocity of at least 10 m / sec while simultaneously maintaining the reduced powder output, more additional air is supplied to the powder feed injector.

[0036] The well-known function of powder feed injectors is as follows: The feed air creates a negative pressure in the powder feed injector, through which coating powder is sucked from a powder reservoir, captured by the feed air, and fed to the powder spray device via a fluid line, such as a powder hose. By changing the pressure and thus also the amount of feed air, the amount of coating powder delivered per unit of time can be adjusted. Since the feed rate depends on the magnitude of the negative pressure created by the feed air in the powder feed injector, the feed rate can also be regulated with constant or variable feed air by introducing additional air into the negative pressure area of ​​the injector via a compressed air inlet device in order to change the magnitude of the negative pressure according to the desired feed rate.This means that the powder feed rate does not depend solely on the conveying air flow, but rather on the difference between conveying air and supplementary air. However, for the reasons mentioned above, the total air flow transporting the coating powder must remain constant for a specific coating process.

[0037] In practice, the operator observes the coating powder cloud directed at the object to be coated and adjusts the pressures of the conveying air and the additional air based on this visual observation. However, this manual adjustment requires a certain amount of experience on the part of the operator. Furthermore, the powder feed rate of the powder feed injector changes during operation. This is primarily due to the fact that the air flow and the powder particles wear down the drive nozzle and the jet catching channel of the powder feed injector during operation. This has the disadvantage that, depending on the degree of wear, the powder volume flow (amount of powder delivered per unit of time) also changes, resulting in uneven coating thicknesses and coating qualities on an object to be coated.

[0038] The invention is therefore based, among other things, on the problem that, during operation of a powder feed injector, it is often only possible with considerable operator experience to estimate when the catcher nozzle or the jet catcher channel of the catcher nozzle is so worn that replacement is necessary. Furthermore, it was considered problematic that, due to the wear on the drive nozzle and the jet catcher channel, the pressures of the conveying air and the auxiliary air often cannot be adjusted to the correct level.

[0039] In particular, it was recognized that there is a growing need for a thin-phase powder pump that can automatically detect the degree of wear on the collecting nozzle. In addition, other functions should also be automatically detected, such as blockages in the powder intake hose, etc.

[0040] FIG. 1 shows schematically and in a sectional view a preferred embodiment of the powder thin-flow pump 51 according to the invention, which is designed to convey powder or coating powder from a (in FIG. 1 not shown) powder reservoir to a (also in FIG. 1 powder spray device (not shown).

[0041] The powder spray device can be a manually operated spray gun or an automatically controlled spray device. It preferably contains at least one high-voltage electrode, which is supplied with high voltage from a high-voltage source for electrostatically charging the coating powder sprayed by the powder spray device. The high-voltage source can be integrated into the powder spray device. The powder spray device can have a spray opening or a rotary atomizer.

[0042] A powder reservoir within the meaning of the present disclosure preferably comprises at least one powder container with a powder chamber from which powder or coating powder is sucked in by means of negative pressure with the aid of the thin-flow powder pump 51, after which the powder or coating powder then flows under positive pressure from the thin-flow powder pump 51 to a corresponding powder spraying device.

[0043] The powder container preferably has at least one powder outlet opening, to which the powder inlet of the thin-phase powder pump is connected. In this context, it is particularly conceivable for the at least one powder outlet opening of the powder container to be arranged in a side wall of the powder container.

[0044] The powder chamber of the powder reservoir can be provided with a fluidizing device for fluidizing the coating powder contained in the powder chamber of the powder container. The fluidizing device can contain at least one fluidizing wall made of an open-pored material or one with narrow holes, which is permeable to compressed air but not to powder or coating powder. In this context, it is particularly advantageous if, in the powder container of the powder reservoir, the fluidizing wall forms the bottom of the powder container and is arranged between the powder chamber of the powder container and a fluidizing compressed air chamber.

[0045] An exemplary embodiment of a powder reservoir designed as a powder container within the meaning of the present disclosure is described, for example, in the document EP 2 675 574 A2.

[0046] The embodiment of the powder thin-phase pump 51 according to the invention, as shown schematically in FIG. 1 is characterized by a modular design and essentially consists of a powder inlet module 80, a pinch valve module 40, a compressed air inlet module 30 and a powder feed injector 100 designed as a pump module at the powder outlet 81 of the thin-phase powder pump 51. These modules are detachably connected to one another in order to form a particularly compact thin-phase powder pump 51.

[0047] As in FIG. 1 schematically shown, the powder thin-phase pump 51 according to the invention has a powder inlet 80, which is connected to the powder inlet by means of a (in FIG. 1 not shown) powder line, in particular by means of an intake pipe or the like, with the already mentioned and in FIG. 1 connected or connectable to a powder reservoir not shown.

[0048] At an opposite end region of the powder thin-phase pump 51, a powder outlet 81 is provided, which is connected to the powder outlet by means of a FIG. 1 not shown powder line, in particular with the aid of a powder hose, is or can be connected in terms of flow to a powder inlet of a powder spraying device (in particular coating gun).

[0049] In detail, the FIG. 1 In the exemplary embodiment shown, both the powder inlet 80 of the thin-phase powder pump 51 and the powder outlet 81 of the thin-phase powder pump 51 are each designed as hose connection pieces, to which the corresponding powder line / powder hose can be plugged and secured, for example, with a hose clamp. Of course, other embodiments for the powder inlet 80 or the powder outlet 81 of the thin-phase powder pump 51 are also possible.

[0050] Preferably, the powder inlet 80 and the powder outlet 81 are located on a common longitudinal axis L (cf. FIG. 3 ) in order to ensure that the powder / coating powder to be conveyed is not or at least only slightly deflected within the thin-flow powder pump 51, which significantly reduces the turbulence of the powder-air mixture in the thin-flow powder pump 51.

[0051] The thin-phase powder pump 51 has a powder feed injector 100, which operates according to the injector principle or Venturi tube principle. For this purpose, the thin-phase powder pump 51 has a powder feed injector 100, in which an air jet creates a vacuum in a vacuum region formed by a channel widening. This vacuum is used to extract powder or coating powder from the powder reservoir via the powder inlet 80 of the thin-phase powder pump 51. The extracted powder or coating powder is entrained by the air jet and conveyed to the powder spraying device. By adjusting the flow rate of the air flow, the vacuum and thus the conveyed powder quantity can be adjusted.

[0052] In the following, with reference to the illustrations in FIG. 2 und 3 An exemplary embodiment of a powder feed injector 100 is described in more detail, which is suitable for use in the powder dilute phase pump 51 according to the invention.

[0053] The exemplary embodiment of the powder feed injector 100 has a first region serving as the drive nozzle 1 and a second region serving as the catcher nozzle 11. The second region of the powder feed injector 100, which serves as the catcher nozzle 11, has a channel serving as a jet catcher channel 12 with a longitudinal axis L within it. A mixture of powder or coating powder and conveying air flows through this channel—for example, when the powder feed injector 100 is used in a dilute phase powder pump 51 for powder conveyance.

[0054] The channel, which is also referred to as the jet catching channel 12 or powder flow channel, has a longitudinal axis L, in which FIG. 2 The flow direction is indicated by an arrow. The mixture of powder / coating powder and conveying air to be conveyed enters the second region serving as the collecting nozzle 11 at a funnel-shaped nozzle inlet 13 and exits the collecting nozzle 11 again at a nozzle outlet 14. At least in the region of the nozzle inlet 13 and in the region of the nozzle outlet 14, the second region serving as the collecting nozzle 11 is cylindrical on the outside, so that corresponding cylindrical guide surfaces 15, 15' are formed.

[0055] The first region of the powder conveying injector 100, arranged upstream of the second region (catching nozzle 11), assumes the function of a driving nozzle 1. The first region (driving nozzle 1) essentially consists of a driving nozzle housing 2 with a conveying air channel 3 and a nozzle 4 which is fluidly connected to the conveying air channel 3 and whose nozzle opening is located axially opposite the jet catching channel 12.

[0056] Although in FIG. 2 not shown, it is conceivable that the nozzle 4 or the nozzle opening is formed by a nozzle mouthpiece, which can be designed as a metal insert and in particular can be inseparably connected to the drive nozzle housing 2.

[0057] In the FIG. 2 In the powder feed injector 100 shown schematically in a sectional view, it can be provided that the first region serving as the propellant nozzle 1 and the second region serving as the catching nozzle 11 are combined as a single component and inseparably connected to one another. In this context, it is fundamentally conceivable to form the first and second regions 1, 11 of the powder feed injector 100 in one piece from one and the same material, for example, as an injection-molded component.

[0058] Alternatively, and as in FIG. 2 As schematically indicated, the first and second regions 1, 11 of the powder feed injector 100 can also be formed separately, in which case these two regions 1, 11 are then detachably or inseparably connected to one another, for example by plugging, gluing, or pressing. This would have the advantage that the two regions 1, 11 of the second region 11 of the powder feed injector 100 can be formed from different materials, in particular different plastic materials.

[0059] A further advantage of this embodiment is that the second region 11 of the powder feed injector 100, which is rotationally symmetrical with respect to the longitudinal axis L of the jet catching channel 12, can be formed as a turned part. This particularly simplifies the manufacture and assembly of the second region 11 of the powder feed injector 100. Furthermore, the second region 11 of the powder feed injector 100 can be replaced individually if necessary, i.e., without the first region 1 of the powder feed injector 100.

[0060] The exemplary embodiment of the powder feed injector 100, as shown schematically in FIG. 2 is shown in a sectional view, is further characterized by the fact that it is a so-called "inline" powder feed injector 100, which means that the powder / coating powder to be fed with the powder feed injector 100 flows axially along the longitudinal axis L of the jet catching channel 12 through the entire powder feed injector 100 (and preferably also through the entire powder dilute phase pump 51).

[0061] In particular, in the exemplary embodiment of the powder feed injector 100, it is provided that the first region 1 of the powder feed injector 100 has a powder inlet 5 which is axially opposite the nozzle outlet 14 of the second region (catch nozzle 11) or the powder outlet of the powder dilution pump 51.

[0062] This axial arrangement of the powder inlet 5 and powder outlet 14 makes it possible to ensure that the powder / coating powder to be conveyed does not have to be deflected or at least only slightly deflected within the powder conveying injector 100, which significantly reduces the turbulence of the powder-air mixture in the powder conveying injector 100.

[0063] In addition, the powder-air mixture in the powder feed injector 100 experiences only minimal flow resistance, which overall increases the conveying capacity achievable with the powder feed injector 100 for the same conveying air quantity.

[0064] In detail, and as in FIG. 2 As indicated schematically, the first region of the powder conveying injector 100, which serves as the propellant nozzle 1, is essentially cylindrical and has a propellant nozzle housing 2 with a substantially cylindrical outer surface. This propellant nozzle housing 2 defines, at least in part, a conveying air channel 3 within the interior, which is arranged axially or at least essentially axially with respect to the longitudinal axis L of the jet catching channel 12. A nozzle projection 6, in which the nozzle opening 4 of the propellant nozzle 1 is formed, extends into the conveying air channel 3.

[0065] The nozzle opening 4 is fluidly connected via the conveying air channel 3 to a conveying air inlet 7, which is arranged and aligned non-axially with respect to the longitudinal axis L of the channel of the second region 11 serving as the jet catching channel 12. On the other hand, as already explained, the nozzle opening 4 of the driving nozzle 1 is arranged axially with respect to the longitudinal axis L of the jet catching channel 12.

[0066] During operation of the powder feed injector 100, conveying air is supplied via the conveying air inlet 7 of the drive nozzle 1, which flows out through the nozzle opening 4 of the drive nozzle 1 in the direction of the jet catching channel 12. Due to the nozzle-shaped arrangement of at least the upstream region of the jet catching channel 12, the conveying air is pressed into the catching nozzle 11, and due to the relatively small diameter of the nozzle opening 4 of the drive nozzle 1, a high-speed air flow is formed, creating a negative pressure in the region of the powder inlet 5 of the powder feed injector 100. This negative pressure, which develops in the powder inlet region during operation of the powder feed injector 100, sucks in coating powder when the powder inlet 5 of the first region 1 of the powder feed injector 100, which serves as the drive nozzle 1, is supplied via a powder channel of the dilute phase powder pump 51 and / or via a powder line, etc.is fluidly connected to a corresponding powder container or the like.

[0067] As in FIG. 2 As indicated schematically, the drive nozzle housing 2 has a cylindrical inner contour at its downstream end region, into which the upstream end region of the second region 11 of the powder feed injector 100, ie the upstream end region of the region of the powder feed injector 100 serving as the collecting nozzle 11, can be inserted and correspondingly detachably or non-detachably connected to the drive nozzle housing 2 (for example by clamping, gluing or pressing).

[0068] Overall, the first and second regions 1, 11 of the powder feed injector 100 are thus connected to one another as a single component. These two interconnected regions 1, 11, combined as a single component, have an overall outer contour that is preferably rotationally symmetrical with respect to the longitudinal axis L of the jet catching channel 12. In this way, the powder feed injector 100 can be inserted as desired into a receptacle 21 of a housing 20 of the dilute powder pump 51, without the user having to pay attention to a specific orientation of the nozzle arrangement 100.

[0069] As shown in the schematic sectional view FIG. 2 can also be removed, the powder feed injector 100 is provided with corresponding seals 8, via which the powder feed injector 100 can be sealed against a housing 20 of the powder dilution pump 51 when the powder feed injector 100 is accommodated in the housing 20 of the powder dilution pump 51.

[0070] Specifically, it is preferred that at least two circumferential sealing areas 8a, 8b are provided, with a groove or annular groove 22 being formed between the two circumferential sealing areas 8a, 8b. The conveying air inlet 7 of the drive nozzle 1 also opens into this area, where the groove or annular groove 22 is formed between the two circumferential sealing areas 8a, 8b.

[0071] FIG. 3 shows schematically and in a sectional view the exemplary embodiment of the powder feed injector 100 according to FIG. 2 in a state in which the powder feed injector 100 is at least partially accommodated in a housing 20 of the powder dilution pump 51.

[0072] As shown, the housing 20 of the thin-phase powder pump 51 has a receptacle 21, the size of which is adapted to the outer diameter and outer configuration of at least the upstream end region of the first region (drive nozzle 1) of the powder feed injector 100. The sealing rings 8a, 8b of the powder feed injector 100 seal at least the upstream end region of the powder feed injector 100 against the wall of the receptacle 21 provided in the housing 20 of the thin-phase powder pump 51.

[0073] The representation in FIG. 3 It can also be seen that the groove or annular groove 22 formed between the two circumferential sealing areas 8a, 8b of the powder feed injector 100 forms an annular space with the wall of the receptacle 21 of the housing 20 of the powder dilute phase pump 51, said annular space being fluidly connected via a conveying air connection 23 formed in the housing 20 of the powder dilute phase pump 51.

[0074] The schematic sectional view in FIG. 3 It can also be seen that a powder line connection 24 is plugged onto the downstream end region of the second region of the powder feed injector 100 (catching nozzle 11) and is in particular detachably connected to the downstream end region.

[0075] For this purpose, the powder line connection 24 has a receiving channel arranged axially with respect to the longitudinal axis L of the jet catching channel 12, in which at least partially the downstream end region of the catching nozzle 11 can be received. Furthermore, as in FIG. 3 schematically indicated - the powder line connection 24 has a corresponding seal 25 in order to seal in particular the powder line connection 24 against the housing 20 of the powder dilution pump 51.

[0076] The powder line connection 24 can be plugged onto the downstream end region of the collecting nozzle 11 in such a way that an annular space 26 is formed, delimited by the housing 20 of the dilute powder pump 51, the powder line connection 24, and the powder feed injector 100. This annular space 26 is fluidly connected to an additional air channel 27 formed in the housing 20 of the dilute powder pump 51. Additional air can be supplied to the annular space 26 via this additional air channel 27, which can be added to the powder-air mixture conveyed by the powder feed injector 100.

[0077] Returning to the presentation in FIG. 1 The exemplary embodiment of the powder thin-flow pump 51 according to the invention is described in more detail below, in which a powder feed injector 100 according to FIG. 2 is used.

[0078] During operation of the thin-phase powder pump 51, conveying air is supplied via the conveying air inlet 7 of the drive nozzle 1 of the powder feed injector 100, which air flows out through the nozzle opening of the drive nozzle 1 in the direction of the jet catching channel 12. Due to the nozzle-shaped arrangement of at least the outflow-side region of the jet catching channel 12, the conveying air is pressed into the catching nozzle 11, and due to the relatively small diameter of the nozzle opening of the drive nozzle 1, a high-speed air flow is formed, creating a negative pressure in the area of ​​the powder inlet of the powder feed injector 100. This negative pressure, which develops in the powder inlet area during operation of the thin-phase powder pump 51, sucks in powder or coating powder if the powder inlet of the first region of the powder feed injector 100, which serves as the drive nozzle 1, is connected to the powder feed injector via a powder line, etc.is fluidly connected to a corresponding powder container or the like. As shown in the schematic sectional view according to . FIG. 1 can also be removed, the powder feed injector 100 is accommodated in a receptacle of the powder dilution pump 51 designed as a pump module, so that the pump module serves as a housing 20 or injector housing with regard to the powder feed injector 100.

[0079] In addition to the powder feed injector 100 described above, the thin-flow powder pump 51 of the exemplary embodiment, designed as a pump module, has a pinch valve 40 which is arranged in a flow path between the powder inlet 80 of the pump module and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100.

[0080] This pinch valve 40 is preferably controllable by a control device of the thin-phase powder pump 51 in order to interrupt, as needed, a flow connection between the powder inlet 80 of the pump module and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100. Such an interruption of the flow path preferably occurs during a cleaning operation of the thin-phase powder pump 51, as described in more detail below.

[0081] In addition, a compressed air inlet device 30 is provided between the pinch valve 40 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100 in order to supply compressed air to the powder feed injector 100 as required. In detail, in the FIG. 1 In the exemplary embodiment of the powder thin-flow pump 51 according to the invention shown, it is provided that the compressed air inlet device 30 is arranged in the flow path between the pinch valve 40 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100.

[0082] The pump module as such has a first compressed air connection 7, via which conveying air can be supplied to the drive nozzle 1 of the powder conveying injector 100. Furthermore, the pump module has a second compressed air connection 27, via which additional air can be supplied to the powder conveying injector 100.

[0083] In addition, the pump module has a third compressed air connection via which compressed air can be supplied to the compressed air inlet device 30 as required, and a fourth compressed air connection via which a corresponding control pressure can be supplied to the pinch valve 40 for actuating the pinch valve 40.

[0084] The pressures required for operating the powder thin-phase pump 51 designed as a pump module are provided by a corresponding compressed air control of the powder thin-phase pump 51.

[0085] As shown, the pump housing 20 of the thin-phase powder pump 51, in which the powder feed injector 100 is at least partially accommodated, has a powder feed channel 60 which fluidly connects the powder inlet 80 of the thin-phase powder pump 51 to the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100. The aforementioned pinch valve 40 is designed to, if necessary, separate a fluid connection formed via the powder feed channel 60 between the powder inlet 80 of the thin-phase powder pump 51 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100.

[0086] In the exemplary embodiment of the thin-phase powder pump 51 according to the invention, it is provided that the powder feed channel 60 runs rectilinearly along a longitudinal axis L, wherein this longitudinal axis L of the powder feed channel 60 coincides with a longitudinal axis L defined by the jet catching channel 12 or runs parallel to a longitudinal axis L defined by the jet catching channel 12.

[0087] As in FIG. 1 As shown, the embodiment of the thin-phase powder pump 51 according to the invention further comprises a compressed air inlet device 30 which opens at a point into the flow connection between the powder inlet 80 of the thin-phase powder pump 51 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100 in order to supply additional compressed air as additional transport compressed air or rinsing air (in a cleaning operation of the thin-phase powder pump 51) as required.

[0088] In detail, the compressed air inlet device 30 is arranged at a point between the pinch valve 40 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100 and opens into the flow connection there.

[0089] The powder thin-phase pump 51 according to the invention, as shown schematically for example in FIG. 1 , further comprises a device for functional testing of the thin-phase powder pump 51 or components thereof. For this purpose, the functional testing device comprises at least one pressure sensor (not shown in the figures) for detecting a static and / or dynamic pressure in an area in the flow connection between the powder inlet 80 of the thin-phase powder pump 51 and the powder inlet 5 of the drive nozzle 1 of the powder conveying injector 100.

[0090] In the embodiment of the thin-flow powder pump 51 according to the invention, the at least one pressure sensor of the device for functional testing is designed to detect a static and / or dynamic pressure in a region in the flow connection between the pinch valve 40 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100. In addition, the at least one pressure sensor can be further designed to detect the temporal progression of a static and / or dynamic pressure over a definable period of time.

[0091] At the FIG. 1 In the schematically shown embodiment of the thin-phase powder pump 51 according to the invention, a filter 61 is assigned to the compressed air inlet device 30, which filter is permeable to air but not to coating powder. The at least one pressure sensor of the device for functional testing is preferably connected to a compressed air path that extends from a compressed air line 58 assigned to the compressed air inlet device 30 to the air side of the filter. The air side is separated by the filter 61 from the flow connection between the powder inlet 80 of the thin-phase powder pump 51 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100.

[0092] The thin-phase powder pump 51 has a conveying air inlet 7 assigned to the powder conveying injector 100 for supplying conveying air to the drive nozzle 1 of the powder conveying injector 100. Furthermore, the thin-phase powder pump 51 has an additional air inlet 27 assigned to the powder conveying injector 100 for supplying additional air into the flow path of a powder-conveying air mixture at the powder outlet 81 of the thin-phase powder pump 51. Although not shown in the drawings, it is advantageous if at least one air adjustment element is provided to adjust the amount of conveying air supplied to the conveying air inlet per unit of time and / or the amount of additional air supplied to the additional air inlet per unit of time.

[0093] The functions that can be implemented by the functional testing facility are described in more detail below.

[0094] In detail, the functional testing facility is designed to detect at least one and preferably all of the following situations: wear and / or degree of wear of the collecting nozzle 11; at least partial blockage at the powder outlet 81 of the thin-phase powder pump 51; at least partial blockage at the powder inlet 80 of the thin-phase powder pump 51; and a lack of coating powder in the powder reservoir fluidly connected to the powder inlet 80 of the thin-phase powder pump 51.

[0095] For this purpose, in addition to the at least one pressure sensor, the device for functional testing is preferably also assigned a powder rate actual value sensor, which is arranged in or near the powder feed injector 100 at or in the flow path of the powder-feed air mixture at the powder outlet 81 of the thin-phase powder pump 51 and is designed to detect a corresponding actual value of a powder rate fed by the powder feed injector 100.

[0096] The device for functional testing of the thin-phase powder pump 51 or components thereof can, for example, detect the wear and / or degree of wear of the collecting nozzle 11 of the powder feed injector 100 by supplying a predetermined amount of conveying air per unit of time to the powder feed injector 100 via the conveying air inlet 7 and a predetermined amount of additional air per unit of time to the powder feed injector 100 via the additional air inlet 27. Subsequently, with the pinch valve 40 closed, the negative pressure established at the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100 is detected. This negative pressure decreases depending on the degree of wear of the collecting nozzle 11, even at the same conveying air and additional air rate.

[0097] Therefore, the thin-phase powder pump 51 preferably has an evaluation device associated with the functional testing device, which is designed to compare the actual pressure value with corresponding predefined or recorded target pressure values. If the deviation between the actual value and the target value exceeds a predefined value, the evaluation device emits a corresponding signal recommending the replacement of the collecting nozzle 11.

[0098] Alternatively or additionally, the device for functional testing is designed to readjust the conveying air rate and / or supplementary air rate depending on the detected degree of wear of the catcher nozzle 11 in order to compensate for the reduced powder volume flow due to the degree of wear of the catcher nozzle 11, specifically by increasing the conveying air rate. This readjustment is preferably carried out automatically, in particular optionally automatically.

[0099] The functional testing device is further configured to detect an at least partial blockage at the powder outlet 81 of the dilute powder pump 51 and to issue corresponding warnings or notifications. This is based on the knowledge that a partial or complete blockage at the powder outlet 81 of the dilute powder pump 51 causes a backflow, which can be detected by the pressure sensor.

[0100] Since the pressure sensor is also designed in particular to record a temporal progression, in particular of a static pressure, the temporal progression of the catcher nozzle wear or a blockage at the powder outlet of the powder dilution pump 51 can also be recorded with the aid of the device for functional testing.

[0101] In addition, with the aid of the functional testing device, at least partial blockage at the powder inlet 80 of the thin-phase powder pump 51 can also be detected. For this purpose, the negative pressure occurring at the powder inlet of the powder feed injector 100 is first detected with the pinch valve 40 closed and a predetermined conveying air and additional air rate. This negative pressure should - if the powder inlet of the thin-phase powder pump 51 is not blocked - suck in the coating powder via the powder inlet 80 of the thin-phase powder pump 51. The pressure at the powder inlet of the powder feed injector 100, which can be detected by the pressure sensor, then increases. However, if the pressure increase does not occur with the pinch valve 40 open, ordoes not exceed a predetermined value, the device for functional testing automatically and in particular preferably automatically detects an at least partial blockage at the powder inlet of the powder dilution pump 51.

[0102] If, however, the pressure exceeds a predetermined upper threshold value when the pinch valve 40 is open, this is due to a lack of coating powder in the powder reservoir fluidly connected to the powder inlet 80 of the thin-phase powder pump 51.

[0103] The device for functional testing is further configured to detect powder line backpressure. For this purpose, with the pinch valve 40 closed, a predetermined amount of additional compressed air is supplied per unit of time to the powder feed channel formed in the pump housing via the compressed air inlet device 30. Depending on the flow resistance and / or the length of a powder line fluidly connected to the powder outlet of the dilute phase powder pump 51, the backpressure detectable by the pressure sensor then changes. This, in turn, allows a statement to be made about the length of the powder line fluidly connected to the powder outlet of the dilute phase powder pump 51 or about the flow resistance of this powder line.

[0104] For this purpose, the device for functional testing preferably has a storage device which stores set values ​​of a static pressure in the area of ​​the flow connection between the powder inlet 80 of the powder thin-flow pump 51 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100 for different powder hoses or powder lines fluidically connected to the powder outlet of the thin-flow powder pump 51 for fixed values ​​of the quantity of conveying air or additional air supplied per unit of time to the conveying air inlet, the additional compressed air inlet.The evaluation device is designed to detect a powder hose / powder line that is actually fluidically connected to the powder outlet of the thin-flow powder pump 51, in particular its length and / or its flow resistance, based on the pressure value detected by the at least one pressure sensor and taking into account the target pressure values ​​stored in the storage device.

[0105] Again, it is advantageous if the powder dilution pump 51 automatically adjusts the conveying air rate and / or additional air rate depending on the length of the powder line or its flow resistance.

[0106] The following is based on the illustration in FIG. 4 a further exemplary embodiment of a powder thin-phase pump 51 not according to the invention is described.

[0107] In short, the further exemplary embodiment of the powder thin-phase pump 51 has a structure which in principle corresponds to the structure of the previously described with reference to the illustration in FIG. 1 described powder thin-phase pump 51.

[0108] As with the presentation in FIG. 1 described embodiment, the powder thin-phase pump 51 according to the invention is FIG. 4 designed to transfer powder or coating powder from a powder reservoir (not shown) to a (also in FIG. 1 powder spraying device (not shown).

[0109] The exemplary embodiment of the powder thin-phase pump 51 according to the invention, as shown schematically in FIG. 4 is again characterized by a modular design and essentially consists of a powder inlet / pinch valve module 40, a compressed air inlet module 30 and a powder feed injector 100 designed as a pump module at the powder outlet 81 of the thin-phase powder pump 51. These modules are detachably connected to one another in order to form a particularly compact thin-phase powder pump 51.

[0110] As in FIG. 4 schematically shown, the non-inventive powder thin-phase pump 51 has a powder inlet 80 on the powder inlet / pinch valve module 40, which is controlled by means of a (in FIG. 4 not shown) powder line, in particular by means of an intake pipe or the like, with the already mentioned and in FIG. 4 The powder inlet / pinch valve module 40 with the powder inlet 80 are arranged relative to the longitudinal axis L of the powder outlet 81 of the powder dilution pump 51 by approximately 60 to 70° in the direction of the powder reservoir (not shown), ie in FIG. 4 downwards, angled, so that the powder inlet / pinch valve module 40 serves at least partially as an intake pipe, which improves the overall response of the thin-phase powder pump 51.

[0111] At an opposite end area of ​​the powder thin-phase pump 51, the already mentioned powder outlet 81 is provided, which is connected to the FIG. 4 not shown powder line, in particular with the aid of a powder hose, is or can be connected in terms of flow to a powder inlet of a powder spraying device (in particular coating gun).

[0112] In detail, the FIG. 4 In the exemplary embodiment shown, both the powder inlet 80 of the thin-phase powder pump 51 and the powder outlet 81 of the thin-phase powder pump 51 are each designed as hose connection pieces, to which the corresponding powder line / powder hose can be plugged and secured, for example, with a hose clamp. Of course, other embodiments for the powder inlet 80 or the powder outlet 81 of the thin-phase powder pump 51 are also possible.

[0113] The powder thin-phase pump 51 according to FIG. 4 has a powder feed injector 100, which operates according to the injector principle or Venturi tube principle. For this purpose, the thin-phase powder pump 51 has a powder feed injector 100, in which an air jet generates a vacuum in a vacuum region formed by a channel widening. This vacuum is used to suck powder or coating powder from the powder reservoir via the powder inlet 80 of the thin-phase powder pump 51. The sucked-off powder or coating powder is entrained by the air jet and conveyed to the powder spraying device. By adjusting the flow rate of the air flow, the vacuum and thus the conveyed powder quantity can be adjusted.

[0114] An exemplary embodiment of a powder feed injector 100 which is suitable for use in the powder dilute phase pump 51 according to FIG. 4 is suitable in FIG. 2 und FIG. 3 To avoid repetition, reference is made here to the previous explanations of the exemplary embodiment of the powder feed injector 100.

[0115] Accordingly, during operation of the thin-phase powder pump 51, conveying air is supplied via the conveying air inlet 7 of the drive nozzle 1 of the powder feed injector 100, which air flows out through the nozzle opening of the drive nozzle 1 in the direction of the jet catching channel 12. Due to the nozzle-shaped arrangement of at least the outflow-side region of the jet catching channel 12, the conveying air is pressed into the catching nozzle 11, and due to the relatively small diameter of the nozzle opening of the drive nozzle 1, a high-speed air flow is formed, creating a negative pressure in the area of ​​the powder inlet of the powder feed injector 100. This negative pressure, which develops in the powder inlet area during operation of the thin-phase powder pump 51, sucks in powder or coating powder if the powder inlet of the first region of the powder feed injector 100, which serves as the drive nozzle 1, is connected to the powder feed injector via a powder line, etc.is fluidly connected to a corresponding powder container or the like.

[0116] As shown in the schematic sectional view FIG. 4 can be removed, the powder feed injector 100 is accommodated in a receptacle of the powder dilution pump 51 designed as a pump module, so that the pump module serves as a housing 20 or injector housing with regard to the powder feed injector 100.

[0117] In addition to the powder feed injector 100 described above, the powder dilute phase pump 51 of the exemplary embodiment, which is designed as a pump module, has a pinch valve 40, which is arranged in a flow path between the powder inlet 80 of the pump module and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100. The pinch valve 40 is in the FIG. 4 shown embodiment of the powder thin-phase pump 51 according to the invention is part of the powder inlet / pinch valve module 40.

[0118] This pinch valve 40 is preferably controllable by a control device of the thin-phase powder pump 51 in order to interrupt, as needed, a flow connection between the powder inlet 80 of the pump module and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100. Such an interruption of the flow path preferably occurs during a cleaning operation of the thin-phase powder pump 51, as described in more detail below.

[0119] Furthermore, it is conceivable that a compressed air inlet device 30 is provided between the pinch valve 40 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100 in order to supply compressed air to the powder feed injector 100 as required. In detail, in the FIG. 4 In the exemplary embodiment of the powder thin-flow pump 51 according to the invention shown, it is provided that the compressed air inlet device 30 is arranged in the flow path between the pinch valve 40 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100.

[0120] The pump module as such has a first compressed air connection 7, via which conveying air can be supplied to the drive nozzle 1 of the powder conveying injector 100. Furthermore, the pump module has a second compressed air connection 27, via which additional air can be supplied to the powder conveying injector 100.

[0121] In addition, the pump module has a third compressed air connection via which compressed air can be supplied to the compressed air inlet device 30 as required, and a fourth compressed air connection via which a corresponding control pressure can be supplied to the pinch valve 40 for actuating the pinch valve 40.

[0122] The pressures required for operating the powder thin-phase pump 51 designed as a pump module are provided by a corresponding compressed air control of the powder thin-phase pump 51.

[0123] As shown, the pump housing 20 of the thin-phase powder pump 51, in which the powder feed injector 100 is at least partially accommodated, has a powder feed channel 60 which fluidly connects the powder inlet 80 of the thin-phase powder pump 51 to the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100. The aforementioned pinch valve 40 is designed to, if necessary, separate a fluid connection formed via the powder feed channel 60 between the powder inlet 80 of the thin-phase powder pump 51 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100.

[0124] As in FIG. 4 As shown, the exemplary embodiment of the thin-phase powder pump 51 not according to the invention further comprises a compressed air inlet device 30 which opens at a point into the flow connection between the powder inlet 80 of the thin-phase powder pump 51 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100 in order to supply additional compressed air as additional transport compressed air or rinsing air (in a cleaning operation of the thin-phase powder pump 51) as required.

[0125] In detail, the compressed air inlet device 30 is arranged at a point between the pinch valve 40 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100 and opens into the flow connection there.

[0126] The non-inventive powder thin-phase pump 51, as shown schematically for example in FIG. 4 , further comprises a device for functional testing of the thin-phase powder pump 51 or components thereof. For this purpose, the functional testing device comprises at least one pressure sensor (not shown in the figures) for detecting a static and / or dynamic pressure in an area in the flow connection between the powder inlet 80 of the thin-phase powder pump 51 and the powder inlet 5 of the drive nozzle 1 of the powder conveying injector 100.

[0127] As with the FIG. 1 In the embodiment of the thin-flow powder pump 51 according to the invention shown, the at least one pressure sensor of the device for functional testing is particularly designed to detect a static and / or dynamic pressure in a region in the flow connection between the pinch valve 40 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100. Alternatively or additionally, the at least one pressure sensor is further designed to detect the temporal progression of a static and / or dynamic pressure over a definable period of time.

[0128] At the FIG. 4 In the schematically shown embodiment of the non-inventive powder thin-phase pump 51, the compressed air inlet device 30 is assigned a filter 61 which is permeable to air, but not to coating powder. The at least one pressure sensor of the device for functional testing is preferably connected to a compressed air path which extends from a compressed air line assigned to the compressed air inlet device 30 (in FIG. 4 not shown) extends to the air side of the filter. The air side is separated by the filter 61 from the flow connection between the powder inlet 80 of the thin-phase powder pump 51 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100.

[0129] The thin-phase powder pump 51 has a conveying air inlet 7 assigned to the powder conveying injector 100 for supplying conveying air to the drive nozzle 1 of the powder conveying injector 100. Furthermore, the thin-phase powder pump 51 has an additional air inlet 27 assigned to the powder conveying injector 100 for supplying additional air into the flow path of a powder-conveying air mixture at the powder outlet 81 of the thin-phase powder pump 51. Although not shown in the drawings, it is advantageous if at least one air adjustment element is provided to adjust the amount of conveying air supplied to the conveying air inlet per unit of time and / or the amount of additional air supplied to the additional air inlet per unit of time.

[0130] The one in FIG. 4 The device for functional testing used in the schematically shown powder thin-phase pump 51 corresponds in functional terms to the device for functional testing used in the FIG. 1schematically shown powder thin-phase pump 51 is used.

[0131] In detail, the functional testing device is designed to detect at least one and preferably all of the following situations: wear and / or degree of wear of the collecting nozzle 11; at least partial blockage at the powder outlet 81 of the thin-phase powder pump 51; at least partial blockage at the powder inlet 80 of the thin-phase powder pump 51; and a lack of coating powder in the powder reservoir fluidly connected to the powder inlet 80 of the thin-phase powder pump 51.

[0132] For this purpose, in addition to the at least one pressure sensor, the device for functional testing is preferably also assigned a powder rate actual value sensor, which is arranged in or near the powder feed injector 100 at or in the flow path of the powder-feed air mixture at the powder outlet 81 of the thin-phase powder pump 51 and is designed to detect a corresponding actual value of a powder rate fed by the powder feed injector 100.

[0133] The device for functional testing of the thin-phase powder pump 51 or components thereof can, for example, detect the wear and / or degree of wear of the collecting nozzle 11 of the powder feed injector 100 by supplying a predetermined amount of conveying air per unit of time to the powder feed injector 100 via the conveying air inlet 7 and a predetermined amount of additional air per unit of time to the powder feed injector 100 via the additional air inlet 27. Subsequently, with the pinch valve 40 closed, the negative pressure established at the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100 is detected. This negative pressure decreases depending on the degree of wear of the collecting nozzle 11, even at the same conveying air and additional air rate.

[0134] Therefore, the thin-phase powder pump 51 preferably has an evaluation device associated with the functional testing device, which is designed to compare the actual pressure value with corresponding predefined or recorded target pressure values. If the deviation between the actual value and the target value exceeds a predefined value, the evaluation device emits a corresponding signal recommending the replacement of the collecting nozzle 11.

[0135] Alternatively or additionally, the device for functional testing is designed to readjust the conveying air rate and / or supplementary air rate depending on the detected degree of wear of the catcher nozzle 11 in order to compensate for the reduced powder volume flow due to the degree of wear of the catcher nozzle 11, specifically by increasing the conveying air rate. This readjustment is preferably carried out automatically, in particular optionally automatically.

[0136] The functional testing device is further configured to detect an at least partial blockage at the powder outlet 81 of the dilute powder pump 51 and to issue corresponding warnings or notifications. This is based on the knowledge that a partial or complete blockage at the powder outlet 81 of the dilute powder pump 51 causes a backflow, which can be detected by the pressure sensor.

[0137] Since the pressure sensor is also designed in particular to record a temporal progression, in particular of a static pressure, the temporal progression of the catcher nozzle wear or a blockage at the powder outlet of the powder dilution pump 51 can also be recorded with the aid of the device for functional testing.

[0138] In addition, with the aid of the functional testing device, at least partial blockage at the powder inlet 80 of the thin-phase powder pump 51 can also be detected. For this purpose, the negative pressure occurring at the powder inlet of the powder feed injector 100 is first detected with the pinch valve 40 closed and a predetermined conveying air and additional air rate. This negative pressure should - if the powder inlet of the thin-phase powder pump 51 is not blocked - suck in the coating powder via the powder inlet 80 of the thin-phase powder pump 51. The pressure at the powder inlet of the powder feed injector 100, which can be detected by the pressure sensor, then increases. However, if the pressure increase does not occur with the pinch valve 40 open, ordoes not exceed a predetermined value, the device for functional testing automatically and in particular preferably automatically detects an at least partial blockage at the powder inlet of the powder dilution pump 51.

[0139] If, however, the pressure exceeds a predetermined upper threshold value when the pinch valve 40 is open, this is due to a lack of coating powder in the powder reservoir fluidly connected to the powder inlet 80 of the thin-phase powder pump 51.

[0140] The device for functional testing is further configured to detect powder line backpressure. For this purpose, with the pinch valve 40 closed, a predetermined amount of additional compressed air is supplied per unit of time to the powder feed channel formed in the pump housing via the compressed air inlet device 30. Depending on the flow resistance and / or the length of a powder line fluidly connected to the powder outlet of the dilute phase powder pump 51, the backpressure detectable by the pressure sensor then changes. This, in turn, allows a statement to be made about the length of the powder line fluidly connected to the powder outlet of the dilute phase powder pump 51 or about the flow resistance of this powder line.

[0141] For this purpose, the device for functional testing preferably has a storage device which stores set values ​​of a static pressure in the area of ​​the flow connection between the powder inlet 80 of the powder thin-flow pump 51 and the powder inlet 5 of the drive nozzle 1 of the powder feed injector 100 for different powder hoses or powder lines fluidically connected to the powder outlet of the thin-flow powder pump 51 for fixed values ​​of the quantity of conveying air or additional air supplied per unit of time to the conveying air inlet, the additional compressed air inlet.The evaluation device is designed to detect a powder hose / powder line that is actually fluidically connected to the powder outlet of the thin-flow powder pump 51, in particular its length and / or its flow resistance, based on the pressure value detected by the at least one pressure sensor and taking into account the target pressure values ​​stored in the storage device.

[0142] Again, it is advantageous if the powder dilution pump 51 automatically adjusts the conveying air rate and / or additional air rate depending on the length of the powder line or its flow resistance.

[0143] The invention is not limited to the exemplary embodiment shown in the drawings, but is defined by the appended claims.

Claims

1. A dilute phase powder pump (51) for conveying powder, in particular coating powder, from a powder reservoir to a powder spraying device, wherein the dilute phase powder pump (51) has a modular structure and comprises the following: - a powder inlet module (80) at a powder inlet (80) of the dilute phase powder pump (51), which is fluidly connectable to the powder reservoir, - a valve device in the form of a pinch valve module (40), - a compressed air inlet module (30), and - a powder-conveying injector (100) in the form of a pump module, having a drive nozzle (1) and a collecting nozzle (11) at a powder outlet (81) of the dilute phase powder pump (51), the powder outlet (81) being fluidly connectable to the powder spraying device, wherein the powder inlet module (80), the pinch valve module (40), the compressed air inlet module (30) and the powder-conveying injector (100) formed as a pump module are releasably connected to one another, wherein the compressed air inlet module (30) is arranged between the powder-conveying injector (100) configured as a pump module and the pinch valve module (40), wherein the valve device formed as a pinch valve module (40) is designed to selectively disconnect a fluidic connection between the powder inlet (80) of the dilute phase powder pump (51) and a powder inlet (5) of the drive nozzle (1), wherein further a device for the functional testing of the dilute phase powder pump (51) or components of the dilute phase powder pump (51) is provided, wherein the device for functional testing comprises at least one pressure sensor for detecting a static and / or dynamic pressure in an area in the fluidic connection between the powder inlet (80) of the dilute phase powder pump (51) and the powder inlet (5) of the drive nozzle (1).

2. The dilute phase powder pump (51) according to claim 1, wherein the valve device comprises a pneumatically actuatable pinch valve (40) provided in the flow path between the powder inlet (80) of the dilute phase powder pump (51) and the powder inlet (5) of the drive nozzle (1).

3. The dilute phase powder pump (51) according to claim 1 or 2, wherein the collecting nozzle (11) comprises a stream collecting channel (12) distanced axially opposite from the drive nozzle (1), and wherein the powder inlet (5) of the drive nozzle (1) is distanced axially opposite from the stream collecting channel (12).

4. The dilute phase powder pump (51) according to one of claims 1 to 3, wherein the powder inlet (5) of the drive nozzle (1) is aligned with respect to an axis which coincides with a longitudinal axis (L) defined by the stream collecting channel (12) or runs parallel to a longitudinal axis (L) defined by the stream collecting channel (12).

5. The dilute phase powder pump (51) according to one of claims 1 to 4, wherein a pump housing (20) is provided in which the powder-conveying injector (100) is at least partially accommodated, wherein a powder supply channel (60) is formed in the pump housing (20), which fluidly connects the powder inlet (80) of the dilute phase powder pump (51) to the powder inlet (5) of the drive nozzle (1), wherein the valve device is designed to disconnect, as required, a fluidic connection formed by the powder supply channel (60) between the powder inlet (80) of the dilute phase powder pump (51) and the powder inlet (5) of the drive nozzle (1).

6. The dilute phase powder pump (51) according to claim 5, wherein the powder supply channel (60) runs in a straight line along a longitudinal axis (L), wherein the longitudinal axis (L) of the powder supply channel coincides with a longitudinal axis (L) defined by the stream collecting channel (12) or runs parallel to a longitudinal axis (L) defined by the stream collecting channel (12).

7. The dilute phase powder pump (51) according to one of claims 1 to 6, which further comprises a compressed air inlet device (30) which opens into the fluidic connection at at least one point between the powder inlet (80) of the dilute phase powder pump (51) and the powder inlet (5) of the drive nozzle (1) in order to supply compressed air as additional compressed conveying air and / or as purge air as required.

8. The dilute phase powder pump (51) according to claim 7, wherein the compressed air inlet device (30) opens into the fluidic connection at a point between the valve device and the powder inlet (5) of the drive nozzle (1).

9. The dilute phase powder pump (51) according to one of claims 1 to 8, wherein the at least one pressure sensor is designed to detect the chronological progression of a static and / or dynamic pressure over a definable period of time.

10. The dilute phase powder pump (51) according to one of claims 1 to 9 in combination with claim 7 or 8, wherein a filter (61) permeable to air but not to powder, in particular coating powder, is allocated to the compressed air inlet device (30), wherein the at least one pressure sensor is connected to a compressed air path which extends from a compressed air line (58) allocated to the compressed air inlet device (30) to the air side of the filter (61), wherein the filter (61) separates the air side from the fluidic connection between the powder inlet (80) of the dilute phase powder pump (51) and the powder inlet (5) of the drive nozzle (1).

11. The dilute phase powder pump (51) according to one of claims 1 to 10, wherein the device for functional testing comprises at least one actual powder rate value sensor which is arranged in or near the powder-conveying injector (100) on or in the flow path of the powder-conveying air mixture at the powder outlet (81) of the dilute phase powder pump (51) for detecting a corresponding actual powder rate value delivered by the powder-conveying injector (100).

12. The dilute phase powder pump (51) according to any one of claims 1 to 11, wherein the dilute phase powder pump (51) comprises a conveying air inlet (7) allocated to the powder conveying injector (100) for supplying conveying air to the drive nozzle (1) and a supplementary air inlet (27) allocated to the powder-conveying injector (100) for supplying supplementary air into the flow path of a powder-conveying air mixture at the powder outlet (81) of the dilute phase powder pump (51), wherein at least one air setting element is provided for setting a volume of conveying air supplied to the conveying air inlet (7) per unit of time and / or for setting a volume of supplementary air supplied per unit of time to the supplementary air inlet (27).

13. The dilute phase powder pump (51) according to claim 12, wherein the device for functional testing comprises an evaluation device for evaluating a static and / or dynamic pressure value detected by the at least one pressure sensor and / or for evaluating a chronological progression of a static and / or dynamic pressure detected by the at least one pressure sensor, wherein the evaluation device is designed to detect at least one and preferably all of the following situations on the basis of the pressure value detected by the at least one pressure sensor and / or the progression of pressure detected by the at least one pressure sensor as well as on the basis of the volume of conveying air or supplementary air respectively supplied to the conveying air inlet and / or the supplementary air inlet per unit of time: - wear and / or degree of wear of the collecting nozzle (11); - an at least partial blockage at the powder outlet (81) of the dilute phase powder pump; - an at least partial blockage at the powder inlet (80) of the dilute phase powder pump; and - a deficiency of powder, particularly coating powder, in the powder reservoir fluidly connected to the powder inlet (80) of the dilute phase powder pump.

14. The dilute phase powder pump (51) according to one of claims 1 to 13, wherein the device for functional testing comprises a storage device in which is stored target values of a static pressure in an area of the fluidic connection between the powder inlet (80) of the dilute phase powder pump (51) and the powder inlet (5) of the drive nozzle (1) for different powder hoses fluidly connected to the powder outlet (81) of the dilute phase powder pump (51) for defined values of the volume of conveying air or respectively supplementary air supplied to the conveying air inlet and / or supplementary compressed air inlet per unit of time, and wherein the evaluation device is designed to detect the pressure of a powder hose actually connected fluidly at the powder outlet (81) of the dilute phase powder pump (51), in particular its length and / or its flow resistance, on the basis of the pressure value detected by the at least one pressure sensor and / or the progression of the pressure detected by the at least one pressure sensor and in consideration of the target values stored in the storage device.