PUMP UNIT, STORAGE DEVICE EQUIPPED THEREWITH, AND METHOD FOR OPERATING THE STORAGE DEVICE

Abstract

In order to make the two pump units which are generally present in an emptying device for a storage container and which feed in alternating fashion as compact as possible on the one hand and subject to as little wear as possible on the other hand, both pump units are preferably equipped with a feed pump in the form of a diaphragm pump, which is driven by a hydraulically operated working cylinder unit.

Claims

1. Pump unit for conveying liquid or pasty material, wherein the pump unit comprises a feed pump which has: a pump element which is movable relative to a feed pump housing in a direction of movement and which is or comprises an elastic element; a feed pump drive in the form of a drive working cylinder which comprises a drive plunger movable in the direction of movement, which is operatively connected to the elastic element, wherein the drive working cylinder can be operated hydraulically and at least one working chamber on a rear side of a drive piston facing away from the pump element has a hydraulic connection.

2. Pump unit according to claim 1, wherein the at least one working chamber on a front side of the drive piston facing the pump element has a hydraulic connection or a pneumatic connection.

3. Pump unit according to claim 2, wherein a drive chamber of the feed pump has a hydraulic connection that can be pressurized with the same pressure as the hydraulic connection of the at least one working chamber, and wherein a connecting line is provided between the at least one working chamber of the drive working cylinder facing away from the feed pump and the drive chamber of the feed pump.

4. Pump unit according to claim 1, wherein the elastic element is a diaphragm, which is fixed with its outer edge tightly to inner sides of the feed pump housing.

5. Pump unit according to claim 1, wherein an effective surface of the drive piston of the drive working cylinder is at most 20% larger than an effective surface of a diaphragm of the feed pump.

6. Pump unit according to claim 1, wherein the elastic element is a bellows which connects the feed pump housing to a pump piston, and the feed pump is a bellows pump.

7. Pump unit according to claim 1, wherein: a position sensor is provided for ascertaining a position of the pump element or of the feed pump drive; and/or a pressure sensor is arranged in a drive chamber of the feed pump.

8. Pump unit according to claim 1, wherein a position sensor is designed as a distance sensor and is arranged on a rear side of the drive plunger facing away from the pump element and measures a position of the drive plunger and/or is arranged in a drive chamber of the feed pump and measures an axial position of the pump element.

9. Pump unit according to claim 1, wherein: a position sensor is a distance sensor which is arranged in a cylinder of the at least one working cylinder unit and; either measures an axial distance to a rear end face of the drive plunger or of the drive piston of the drive working cylinder or measures a radial distance to a surface of the drive piston that is at an angle to an axial direction.

10. Pump unit according to claim 1, wherein a controller is provided for controlling moving parts of the pump unit.

11. Pump unit according to claim 1, wherein the feed pump housing has a heating device for heating an interior of the feed pump.

12. Pump unit according to claim 1, wherein the feed pump has a leakage sensor which is capable of detecting a leak in the pump element.

13. Pump unit according claim 12, wherein the leakage sensor is a liquid sensor on a drive side of a diaphragm or is a pressure sensor that detects a change in pressure on the drive side of the diaphragm.

14. Storage device comprising: a storage container filled with liquid or pasty material; at least one pump unit for emptying the storage container; and a controller for controlling at least moving components of the at least one pump unit, wherein the at least one pump unit is designed according to claim 1.

15. Storage device according to claim 14, wherein the storage device comprises two pump units that can be operated and controlled independently of one another.

16. Storage device according to claim 14, wherein a connecting line is provided between an air chamber of the storage container and a drive chamber of the feed pump.

17. Method for operating the pump unit according to claim 1, wherein the feed pump drive is operated hydraulically at least in a direction in which it moves the pump element in a discharge direction.

18. Method according to claim 17, wherein the at least one working chamber comprises two working chambers and both working chambers of the drive working cylinder are alternately pressurized with pressure medium.

19. Method according to claim 17, wherein an axial position of a movable monitored element of the pump unit is ascertained directly or indirectly.

20. Method according to claim 19, wherein the axial position of the monitored element is determined over an entire movement path and a controller of the pump unit uses a position signal to provide a drive pressure that is defined for each axial position and/or a constant outlet pressure at an outlet opening of a feed chamber.

21. Method according to claim 17, wherein a drive chamber of the feed pump is pressurized with negative pressure.

22. Method according to claim 17, wherein an inlet valve is closed as soon as a position sensor signals that an end position of a diaphragm of the feed pump has been reached in a filling position.

23. Method according to claim 20, wherein the controller emits an alarm signal as soon as a leakage sensor in a drive chamber of the feed pump reports a leak.

24. Method according to claim 17, wherein the at least one working chamber of the feed pump is pressurized with hydraulic medium.

Description

C) EMBODIMENTS

[0063] Embodiments in accordance with the invention are described in more detail below by way of example. In the figures:

[0064] FIG. 1b: shows the pump unit in the center position (normal position),

[0065] FIG. 1a: shows the pump unit at the end of the filling stroke,

[0066] FIG. 1c: shows the pump unit at the end of the feed stroke,

[0067] FIG. 2: shows the entire storage device in vertical section with at least one pump unit.

[0068] The structure of a pump unit 1 according to the invention can best be seen in the sectional view in FIG. 1:

[0069] The pump unit 1 consists of a feed pump 1.1 in the form of a diaphragm pump, and a diaphragm 4 serving as the pump element 3 in the direction of movement 10, a feed pump drive 8 coaxially upstream of this diaphragm pump and connected to it in the form of a hydraulically operated working cylinder unit 1.2, i.e. a hydraulic cylinder 8.

[0070] Both the diaphragm 4 and the drive piston 1.2a coaxial thereto of the working cylinder unit 1.2 are rotationally symmetrical, viewed in the direction of the longitudinal central axis 1, which is perpendicular to the main plane 3, which here runs approximately horizontally, of the diaphragm 4 and of the drive piston 1.2a and at the same time is the direction of movement of the drive piston 1.2a, and in the installed state is often identical to the vertical 11.

[0071] The feed chamber 1.1a has an inlet opening 5a in the upper region, via which the material M can flow into the feed chamber 1.1a when the inlet valve 5 arranged in or at the inlet opening 5a is open, the outlet valve 6 then generally being closed.

[0072] In the upper region, the feed chamber 1.1a also has an outlet opening 6a, in or at which an outlet valve 6 is arranged, so that material M can flow out of this outlet opening 6a when this outlet valve 6 is open, the inlet valve 5 then generally being closed.

[0073] In this way, the feed chamber 1.1a is filled with material M when the diaphragm 4 moves away from the inlet opening 5a (filling stroke) and the material M in the feed chamber 1.1a is ejected into the outlet opening 6a when the diaphragm 4 moves towards the outlet opening 6a (feed stroke), generally being controlled by a controller 1*.

[0074] The feed pump 1.1 is driven, i.e. its diaphragm 4 is moved alternately back and forth transversely to its main plane 4, by means of a drive plunger 9 engaging in the center of the diaphragm 4 on its rear side, i.e. from the drive chamber 1.1b.

[0075] The feed pump drive 8 in the form of a hydraulic cylinder 8 comprises a drive piston 1.2a, which can move back and forth in a drive cylinder 1.2b between two end positions, in particular two stops, preferably in the same direction of movement in which the diaphragm 4 of the diaphragm feed pump 1.1 coupled to the feed pump drive 8 can also move.

[0076] However, the effective surface of the drive piston 1.2a is selected to be barely, at most 20%, better at most only 10% larger, preferably the same or at least 10%, better at least 20%, smaller than that of the diaphragm 4, in order to make possible a compact design of the drive cylinder and thus of the entire pump unit.

[0077] The hydraulic cylinder 8 has a hydraulic connection 13 at least as shown on the pressure side of the drive piston 1.2a facing away from the diaphragm 4 and the feed pump 1.1 in the working chamber of the drive cylinder 1.2b. However, it will generally also have such a hydraulic connection on the other side of the drive piston 1.2a, the pull side, in order to be able to actively and thus more quickly pull the diaphragm 4 back from the inlet opening 5a and accelerate the filling of the feed pump 1.1. For this purpose, the two hydraulic connections 13 can be supplied from the same pressure medium source and selectively fed to one of the two working chambers of the hydraulic cylinder via a directional control valve 20.

[0078] The working chamber 1.1b of the feed pump 1.1 can also have a hydraulic connection in that it is preferably connected to the working chamber of the hydraulic pump remote from the diaphragm pump via a connecting line 19 and optionally a proportional valve 18.

[0079] A proportional valve 16 is preferably connected upstream of the, in particular each, hydraulic connection 13, which valve can be connected to the controller 1* of the pump unit 1 and can be controlled by it, as described above.

[0080] For this purpose, constant knowledge of the position of the drive piston 1.2a is essential, for which reason a position sensor 17 is arranged in the base of the drive cylinder 1.2b, preferably in the form of a distance sensor, which measures the distance of the drive piston 1.2a from the base of the cylinder 1.2b and reports it to the controller 1*. This sensor on the sensor cover (in the center at the bottom). This sensor measures the position of the piston via the conical surface in the piston.

[0081] The pump unit 1 preferably has a pressure connection 12 (pressure connection 12 in FIG. 1.1b), namely in the drive chamber 1.1b of the feed pump 1.1, whereby the filling process can be supported by applying negative pressure, especially if the storage container 101 from which the material M is removed is also under negative pressure. Of course, this only makes sense when this drive compartment 1.1b does not have a hydraulic connection.

[0082] A leakage sensor 15 is preferably arranged in the side of the diaphragm 3 facing away from the feed chamber 1.1a, the drive chamber 1.1b, which sensor detects material M that has penetrated there, which occurs at most in the event of a leak in the diaphragm 3 itself or in its circumferential clamping. As a rule, such a leakage sensor 15 is a liquid sensor, which however is also only useful when this drive chamber 1.1b of the feed pumps 1.1 does not have a hydraulic connection.

[0083] The drive piston 1.2a is connected to the diaphragm 3 via a drive plunger 9, which is arranged centrally, i.e. running along the axial direction 10, the direction of movement, and is attached to the diaphragm 3 on its rear side, i.e. the side of the drive chamber 1.1b.

[0084] There can preferably also be a pressure sensor 16 in this drive chamber 1.1b, which sensor can be in particular designed to be functionally combined with the leakage sensor.

[0085] The drive plunger 9 can be designed in multiple parts:

[0086] On the one hand, it comprises the shaft 9.1, which substantially bridges the distance from the drive piston 1.2a to the diaphragm 4, as well as a pressure plate 9.2, which is located at the end of the shaft 9.1 at the diaphragm side and abuts the diaphragm 4 with a large contact surface 9a (9.a is not shown in the drawing).

[0087] Viewed in cross-section, the diaphragm 4 has, in addition to the central region 4.2 which is continuous within the circumferential clamping of the in particular covered edge 4.1, an annular extension 4.4 to or in the drive chamber 1.1b, wherein the inner circumference of the extension 4.3 ends freely and its outer circumference is integrally connected to the rear side of the continuous main part 4.3 of the diaphragm, in particular to the central region 4.2.

[0088] In the intermediate space between the main part 4.3, continuous from one edge to the other, and the extension 4.4, there is a tension plate 9.3 which, on its rear side, has a centrally situated stem which protrudes through the opening of the extension 4.4 in the direction of the shaft 9.1 and is connected thereto, preferably screwed into it.

[0089] The tension plate 9.3 is used to be able to pull back the diaphragm 4 with a large engagement surface in the form of the extension 4.1 in the event of a rapid backward movement of the drive piston 1.2a caused by compressed air (the compressed air option for the backward movement needs to be described in more detail).

[0090] FIGS. 1a to c show the various functional positions of the drive piston 1.2a and of the diaphragm 4.

[0091] As can be seen, in the central position of the drive piston 1.2a according to FIG. 1b the diaphragm 4 is slightly curved at the center in the direction of the feed chamber 1.1a in the shape of a bulge 4B, and in the region between the outer diaphragm edge 4.1, tightly clamped in the pump housing 2, and the central region 4.2 which abuts the tension plate 9.3, it is slightly curved in cross-section in the direction of the drive chamber 1.1b in the shape of an annular bulge 4A, whereby a radial length reserve is formed for the two end positions:

[0092] When the drive piston 1.2a is at the end of the feed stroke, in particular abutting an axial stop of the feed pump housing 2 formed on the drive cylinder 1.2b as shown in FIG. 1c, this bulge 4A is pulled almost flat, and the diaphragm 4 almost reaches the inlet opening 5a and the outlet opening 6a, but not to the point of contact, in order to prevent damage to the diaphragm 4 by the edges of these openings.

[0093] In the other end position according to FIG. 1a, at the end of the filling stroke and the beginning of the feed stroke, i.e. when the feed chamber 1.1a is completely filled with material M and the piston 1.2a abuts another axial stop of the cylinder 1.2b, the diaphragm 4 lies with its central region further away from the inlet opening 5a and the outlet opening 6a than the edge 4.1 of the diaphragm 4, which is tightly clamped in the pump housing 2, so that in the radial region in between, the diaphragm 4 in particular is curved in the opposite direction to the curvature in the middle, central region, but is flatter than in the center position in FIG. 1b.

[0094] The inlet valve 5 and the outlet valve 6 in FIGS. 1a-c are designed as an active, i.e. driven, shut-off valve 14.

[0095] Instead of having an identical design to the inlet valve 5, the outlet valve 6 can also be designed as a simple non-return valve 7, as shown in FIG. 1b, in that, in this case, a ball, as the valve body 7.1, rests on the upward-facing valve seat 7.2 due to gravity when the same pressure prevails on both sides of the valve body 7.1, and of course even more so when a higher pressure is present on the side of the valve body 7.1 facing away from the valve seat 7.2 than on the other side.

[0096] For this reason, the outlet valve 6 should preferably be arranged with the valve seat 7.2 pointing upwards within the storage device 100 and preferably lying lower than the storage container 101 (a lower situation is not absolutely necessary).

[0097] This pump unit is used for the A2xx and not for the LP804.

[0098] FIG. 2 shows an overall storage device 100, into the frame of which the previously described pump unit 1 can be placed, in a vertical section along the generally upright longitudinal central axis 101, which is also the axis of symmetry of the substantially rotationally symmetrical storage container 101, comprising a pot 101.1, which can be closed tightly by a lid 101.2.

[0099] This pot is filled or can be refilled with material M via an inlet opening 103 and has one or two outlet openings 102 in the base 108, to each of which a pump unit 1 is connected with its inlet nozzle.

[0100] The at least one inlet opening 103 is here positioned in such a way that the material M falling downwards from it meets a truncated-conical drainage surface 110a of a drainage body 110 and flows downwards and radially outwards along it to its lower drip edge 109 in a thin layer, thereby degassing it.

[0101] Since the wall 107 of the pot 101.1 is not vertical, but is inclined radially upwards and outwards, and the drip edge 109 is located in the upper region of the storage container 101 near the inner surface 107a of the wall 107, the material M flows downwards from the drip edge 109 and meets the inner surface 107a of the wall 107, where it continues to run downwards as a thin layer and continues to degas.

[0102] The one or two pump units 1 are arranged so as to be situated horizontally with the diaphragm planes 3 of the feed pumps 1.1.

[0103] The storage container 101 is usually under negative pressure, in that in the lid 101.2, in addition to the inlet opening 103 there is also a negative pressure connection 104 which is coupled to a negative pressure pump 105. The interior of the storage container 101 is connected to the housing cavity of the feed pump 1.1 via a connecting line 113.

[0104] The storage container 101 often comprises a stirrer 106, which prevents sedimentation of heavy components of the material M by rotating around the longitudinal central axis 101.

[0105] The motor 111 which drives the stirrer 106 is mounted on the upper side of the lid 101.2 and its motor-driven shaft 111a extends through this lid 101.2 in a sealed manner into the interior of the pot 101.1 and is connected to the upper ends of the stirrer blades 112a,b which rotate in the pot 101.1.

[0106] A rod-shaped fill-level sensor 114 extends upward from the base 108.

[0107] The drainage body 110 can be mounted in a stationary manner on the lid 101.2 or can be fastened to it so as to co-rotate with the stirrer 106, preferably at the upper region of the stirrer blades 112a-c.

[0108] Furthermore, a heating device 107 in the form of, for example, heating wires may be provided in the storage container 101, in particular in its wall, in order to heat the material M and thereby to thin it.

[0109] The controller 100* of the storage device 100 can also contain the controller 1* of the at least one pump unit 1.

LIST OF REFERENCE NUMBERS

[0110] 1 Pump unit [0111] 1 Longitudinal central axis [0112] 1* Controller [0113] 1.1 Feed pump [0114] 1.1a Feed chamber [0115] 1.1b Drive chamber [0116] 1.2 Working cylinder unit, drive working cylinder [0117] 1.2A Drive cylinder [0118] 1.2B Drive piston [0119] 1.2a Working chamber [0120] 1.2b Working chamber [0121] 2 Feed pump housing [0122] 3 Pump element [0123] 4 Elastic element, diaphragm, feed diaphragm, bellows [0124] 4.1 Diaphragm edge [0125] 4.2 Central region [0126] 4.3 Continuous main part [0127] 4.4 Diaphragm extension [0128] 4b Drive side [0129] 4A, B Bulge, warping [0130] 4 Main plane [0131] 5 Inlet valve [0132] 5a Inlet opening [0133] 6 Outlet valve [0134] 6a Outlet opening [0135] 7 Non-return valve [0136] 7.1 Valve body [0137] 7.2 Valve seat [0138] 8 Feed pump drive [0139] 9 Drive plunger [0140] 9a Contact surface [0141] 9.1 Shaft [0142] 9.2 Pressure plate [0143] 9.3 Tension plate [0144] 10 Direction of movement, axial direction [0145] 11 Vertical [0146] 12 Pressure connection [0147] 13 Hydraulic connection [0148] 14 Shut-off valve [0149] 14a Valve body [0150] 14b Valve seat [0151] 15 Leak sensor [0152] 16 Pressure sensor [0153] 17 Position sensor [0154] 18 Proportional valve [0155] 19 Connecting line [0156] 20 Directional control valve [0157] 100 Storage device [0158] 100* Controller [0159] 101 Storage container [0160] 101 Longitudinal central axis [0161] 101.1 Pot [0162] 101.2 Lid [0163] 102 Outlet opening [0164] 103 Inlet opening [0165] 104 Negative pressure connection [0166] 105 Negative pressure pump [0167] 106 Stirrer [0168] 107 Wall [0169] 107a Inner surface [0170] 108 Base [0171] 109 Edge, drip edge [0172] 110 Drainage body [0173] 110 Axis of rotation [0174] 110a Drainage surface [0175] 111 Stirrer drive, motor [0176] 111a Motor shaft, driven shaft [0177] 112a, b Stirrer blade [0178] 113 Cross-strut [0179] 113.1 Central plate [0180] 114 Fill level sensor [0181] 115 Inlet valve [0182] 116 Window [0183] 117 Connection box [0184] 118 Vertical arm [0185] 119 Stirring plate [0186] M Material [0187] V Vertical