EMPTYING DEVICE FOR VISCOUS MATERIALS AND METHOD FOR SAME

Abstract

In order to prevent the material (52) from being pressed through the press plate seal between press plate (2) and surrounding barrel (50) by means of a press plate (2) when emptying a barrel (50) in which viscous material (52) is supplied, a two-stage construction is used in accordance with the invention:

A press cylinder (22) is connected to the rear side of the press plate (2), in which in turn a conveying piston (24) is guided in a sealing manner, which in turn has a smaller end face than the press plate (2). In addition, non-return valves (19) are arranged in the press plate (2) in the region radially inside the press cylinder (22), which allow the material (52) to flow only in the direction of the conveying piston (24), but not vice versa, when the press plate (2) is pressed in the direction to the bottom (50a) of the barrel (50).

After the press plate (2) has come to a standstill, the conveying piston (24) can thus be guided in the direction of the bottom of the press cylinder (22), i.e. in the direction of the press plate (2), and the material (52) can thereby be pressed through the conveying piston (24) into the conveyer line (4) with a pressure, which can also be significantly higher than the maximum pressure with which the press plate seal between the press plate (2) and the inner circumference of the barrel (50) may be pressurised, which, however, does not pose a problem for the much more accurate press cylinder seal between the conveying piston (24) and the press cylinder (22).

Claims

1. An emptying device for supplying a consumer (53) with viscous material (52) from a barrel (50) having an open side (50a) and a peripheral wall (50b) running in the axial direction (10), the emptying device comprising: a frame (1) for receiving the barrel (50), a movable press plate (2), the which can be driven both in the press direction (10a) and in the withdrawal direction (10b) by a press plate drive (5), fits into the barrel (50) from the open side and, thereby same time, bears closely with its outer edge against the inner surface of the peripheral wall (50b) of the barrel (50), a conveyer line (4), connected to a through opening (3) of the press plate (2), for the material (52) to be conveyed away, characterised in that a press cylinder (22) extends from the rear side of the press plate (2) in the retraction direction (10b), at least one non-return valve (19) with a passage direction (19) from the front side (2a) to the rear side (2b) of the press plate (2) is located in the radial region within the press cylinder in the press plate (2), a conveying piston (24) which can be moved both in the press direction (10a) and in the withdrawal direction (10b) by a conveying drive (5) is present in the press cylinder, the outer edge of the conveying piston (24) lies closely against the inner surface of the peripheral wall (50b) of the press cylinder (22), the conveying piston (24) has a through opening (3) to the rear of which the conveyer line (4) is connected.

2. The emptying device according to claim 1, characterised in that the inner diameter of the press cylinder (22) is smaller than the free inner diameter of the peripheral wall (50b) of the container (50) and the inner diameter of the press cylinder (22) is at least 5% smaller than the free inner diameter of the peripheral wall (50b) of the barrel container (50).

3. The emptying device according to claim 1, characterised in that the press plate drive (5) or the conveyor drive (5), which may also be functionally combined to a single drive, comprise one or two threaded spindles running in parallel or a working cylinder.

4. The emptying device according to claim 1, characterised in that the at least one non-return valve (19) is a ball valve or the sum of the free passages of the non-return valves (19) present in their open state is at least 15% of the bottom area of the compression cylinder (22).

5. The emptying device according to claim 1, characterised in that the press plate (2) is made in one piece with the press cylinder (22) or the press plate (2) is fastened to the press cylinder (22) in a dismountable and mountable manner.

6. The emptying device according to claim 1, characterised in that at least one pressure sensor (54) is present at the conveying piston (24) or close to the consumer, which pressure sensor measures pressure in the material (52), or at least one position sensor (55) is present at the press plate (2) or at the conveying piston (24), which sensor either measures the axial position of the press plate (2) in the emptying device or measures the axial position of the conveying piston (24) in the press cylinder (22).

7. The emptying device according to claim 1, characterised in that the conveyer line (4) consists at least in sections of a flexible hose and a hose pump acting on the hose from the outside is arranged at the flexible hose, or a vacuum connection (7) is present in the front side (2a) of the press plate (2) radially away from the press cylinder (22) or in the conveyer line (4) at or near the consumer, or the inner surface of the conveyer line (4) has a friction-reducing surface.

8. The emptying device according to claim 1, characterised in that a buffer for material (52) is present in the conveyer line (4), in the form of a piston pump or a diaphragm pump, having a sufficiently large volume in order to be able to continue to supply the consumer with material (52) from the buffer in case of a standstill of the emptying of the container (50).

9. The emptying device according to claim 1, characterised in that the frame (1) comprises an enclosure (6) which can be tightly closed or opened for introducing at least the part of the container with the open side or for introducing the entire container (50), the enclosure (6) has a vacuum connection (7) via which the internal space (9) of the enclosure (6) can be connected to a vacuum source (8), the piston rod (17) of the conveying piston (24) and the press cylinder (22) extend through the wall of the enclosure (6).

10. A method for emptying viscous material (52) from a barrel (50) which is open on one side by means of an emptying device according to claim 1, in that the press plate (2) is placed on the surface of the material (52) in the barrel (50), wherein the conveying piston has an axial starting position relative to the press plate (2) and in this case touches in particular the rear side (2b) of the press plate (2), and then a) the pressing plate (2) is further moved into the barrel (50) in the conveying direction (10a) until the material (52) passing through the at least one non-return valve has filled the press cylinder to a predetermined filling level and has thereby in particular pushed the conveying piston in the press cylinder rear side in the withdrawal direction (10b), b) the press plate (2) is stopped, and c) with the press plate (2) stationary, the conveying piston is moved further into the press cylinder in the conveying direction (10a) until it has reached a predetermined target position relative to the press plate (2).

11. The method according to claim 10, characterised in that steps a) to c) are repeated several times in succession until the pressing plate (2) has reached the bottom of the barrel (50).

12. The method according to claim 10, characterised in that the starting position or the target position of the conveying piston (24) are adjustable.

13. The method according to claim 10, characterised in that the pressure in the material (52) is measured on the front side (2a) of the pressing plate (2) or on the front side of the conveying piston or in the conveyer line (4) close to the consumer and is reported to a controller and, depending thereon, the press plate drive (5) or the conveying piston drive (5) is controlled by a controller, taking into account the time delay of the pressure progress along the conveyer line (4).

14. The method of claim 10, characterised in that before and during placing the press plate (2) on the upper side of the material (52) in the barrel (50), the space between is pressurised with negative pressure, in that the barrel (50) open on one side is completely or at least with its open side introduced into an enclosure (6), the enclosure (6) is tightly closed and then the internal space (9) of the enclosure (6) is pressurised with negative pressure.

Description

[0062] A a state-of-the-art barrel press with open vacuum container shows

[0063] FIG. 1a: in the front view,

[0064] FIG. 1 in the side view,

[0065] FIG. 1c: in the top view,

[0066] FIG. 2: in vertical section in direction of view from the front and a barrel press according to the invention shows

[0067] FIG. 3: in the same vertical section as FIG. 2,

[0068] FIGS. 4a to e: in different functional positions of the barrel press according to FIG. 3

[0069] FIGS. 1a, b, c and 2 show an emptying device in the form of a barrel press in exterior views and in sectional views:

[0070] Material 52 is to be conveyed from the barrel 50, which is open at the top and shown in FIGS. 1a and 2, by the pressing plate 2, which can be tightly pushed into the inner circumference of the barrel 50 from above, and exerts pressure on the material 52 with its pressure side 2a, so that the material 52as can best be seen in FIG. 2is then pressed upwards by the hollow piston rod 17 projecting from the opposite rear side 2b and is pushed by the conveyer line 4 connected thereto to the consumer 53 indicated only in FIG. 2.

[0071] Since this process is to take place under negative pressure, i.e. ideally under vacuum, the barrel 50 is first placed in an enclosure 6 consisting of a solid housing 6a and the door 6b shown in the opened state, which seals the enclosure 6 in the closed state, in whose internal space 9 the desired vacuum is generated. For this purpose, enclosure 6 has a vacuum connection 7 which connects enclosure 6 to a vacuum source 8.

[0072] As the only element the piston rod 17, at the front end of which the pressing plate 2 is fixed and which moves the pressing plate 2, extends through the top of the enclosure 6 into its internal space 9, the passage being appropriately sealed so that no air from outside can penetrate into the internal space 9 which is under negative pressure.

[0073] Since very high forces of up to 100 tons have to be applied to the press plate 2 or the piston rod 17 driving it in the case of highly viscous materials for this purpose, the enclosure 6 is located in a solid frame 1, in the upper area of which two vertically arranged and parallel threaded spindles 15 or also ball screw spindles are arranged side by side, which act jointly on a transverse yoke 12, which is connected to the rear, upper end of the hollow piston rod 17, which extends to the press plate 2.

[0074] In order to prevent the pressure exerted by the press plate 2 on the material 52 in the barrel 50 from deforming the barrel 50 radially or even bursting the barrel 50, a stable surrounding 13see FIG. 1ais usually fitted around the barrel 50 using state-of-the-art technology, which lies close to the outer sides of the barrel 50 and withstands the pressure prevailing therein.

[0075] However, even in this case, the pressed-plate gasket is not completely tight due to deformation of the barrel, and in addition, such a stable surrounding 13 not only requires time and effort to manufacture the device, but also, depending on the dimension of the barrel, a separate, matching surrounding 13 is required, usually also for the barrels of different manufacturers.

[0076] Even when setting a new barrel 50 in an surrounding with such a stable surrounding for the barrel, this makes the setting process of each barrel cumbersome and error-prone.

[0077] A further disadvantage is the fact that barrels have a relatively large range of variation in their actual dimensions, especially with regard to wall thickness, inner diameter and outer diameter.

[0078] In accordance with the invention, it is therefore proposed to design the emptying device according to FIG. 3 using the same view as FIG. 2:

[0079] It can be seen here that a press cylinder 22 extends upwards from the rear side 2b of the press plate 2, i.e. in the withdrawal direction 10b of the axial direction 10, and in the cross-section of the press plate 2 within the inner circumference of this press cylinder 22 there are at least one, generally several, through openings 3 for the material 52 to be conveyed, which are now, however, in each case constructed as non-return valves 19, in this case with a ball 19a as valve unit. The flow direction of this at least one non-return valve 19 is exclusively the direction from bottom to top, i.e. into the inside of the press cylinder 22, and not vice versa.

[0080] The press plate 2 usually rests against the inner circumference of the wall 50b of the barrel 50 via several press plate gaskets 14 arranged one behind the other in the axial direction 10.

[0081] The press cylinder 22 is hollow in axial direction 10 and in it a press piston 24 is tightly guided so that it can be moved in axial direction, sealed by several conveying piston seals 23, which are usually arranged one behind the other in axial direction.

[0082] The conveying piston 24 has a central through opening 3, which opens into the piston rod 17, which is hollow in the axial direction and extends upwards from the conveying piston 24, i.e. in the withdrawal direction 10b, and to which in its upper, downstream end region the conveyer line 4 is connected, which leads to the consumer 53.

[0083] The pressing plate 2 on the one hand and the conveying piston 24 on the other hand can be moved independently in axial direction 10 both in press direction 10a and in withdrawal direction 10b.

[0084] The positions of conveying piston 24 and press plate 2 can each be monitored by each one or a common position sensor 55, one of which is located at the enclosure 6 next to the opening for the piston rod 17 as shown in FIG. 3 and the other at the piston rod 17. There may also be a pressure sensor 54, for example in the underside of the conveying piston 24, to measure the pressure in the material 52 below.

[0085] The movement takes place either by means of a common drive 5, but nevertheless independently of each other in so far as with this common drive 5 either the press cylinder 22, i.e. the piston rod of the pressing plate 2, or the piston rod 17 of the conveying piston 24 or both can be coupled simultaneously.

[0086] The press cylinder 22 is slidably and can be moved in the passage in the upper side of the housing 6 sealed in axial direction, as it was also the case with the state of the art solution for the piston rod 17 of the press plate 2.

[0087] Of course, it is also possible to drive the press plate 2 on the one hand and the conveying piston 24 on the other hand in axial direction by means of separate drives, i.e. to couple one drive each with the press cylinder 22 on the one hand and with the piston rod 17 on the other hand.

[0088] With this construction of the emptying device it is possible to insert the press plate 2 into the open upper side of the barrel 50, to place it on the material 52 to be removed and by further moving the press plate 2 downwards to let the material 52 flow through the through openings 3 of the press plate 2the passage direction 19 of the non-return valves 19in the area above the press plate 2 and thus into the press cylinder 22. The prerequisite for this is that the conveying piston 24 does not resist the material 52 when it reaches it, but only the sliding friction between the conveying piston seal 23 and the press cylinder 22 must be overcome, as well as the dead weight of the conveying piston 24 and its piston rod 17.

[0089] When press plate 2 and conveying piston 24 are driven together, the press plate 2 must not be pressed down by the common drive 5 and the conveying piston 24 must not be coupled to this drive but must be freely movable relative to this drive.

[0090] In order to press the material through the piston rod 17 and the connected conveyer line 4 to the consumer, a considerably higher pressure is required. This is applied by, after sufficient filling of the internal space of the press cylinder 22 with material 52, stopping the forward movement, i.e. downward movement, of press plate 2 and pressing the conveying piston 24 downwards with press plate 2 stationary. With a common drive 5, this means that press plate 2 must be uncoupled from drive 5 and the conveying piston 24 must be connected directly to drive 5 instead.

[0091] However, the necessary high pressure now only occurs between the upwardly facing rear side of the press plate 2 including the non-return valves 19which are not permeable to the material 52 from top to bottomand the conveying piston 24 and thus also in the piston rod 17, but not in the area between the bottom 50a of the barrel 50 and the press plate 2. Thus this high pressure also does not affect the press plate gasket 14 between the press plate 2 and the barrel 50, the sealing effect of which can thus be considerably lower than that of the conveying piston seal 23.

[0092] In addition, the pressure between press plate 2 and conveying piston 24when the same force is applied as with the known solution according to FIGS. 1 and 2is significantly higher due to the smaller cross-sectional area of the conveying piston 24 compared to the cross-sectional area of the press plate 2 as it is relevant with the known solution. This means that a weaker drive 5 is sufficient to generate the same pressure in the solution according to the invention.

[0093] In this way a barrel can now be emptied in one or more steps, as can be seen from FIG. 4a-e:

[0094] In the first step according to FIG. 4a, the press plate 2 is inserted into the barrel 50, placed on the surface of the material 52 contained therein, and moved downwards until a sufficient amount of material in the press cylinder 22 is below the conveying piston 24, which has thereby either been pushed up or has already been in a pushed up position relative to the press plate 2.

[0095] Afterwards the press plate 2 is stopped according to FIG. 4b and by moving the conveying piston 24 down, i.e. moving it in forward direction, the material between the stationary press plate 2 and the conveying piston 24 is pressed as far as possible into the piston rod 17 and thus finally into the conveyer line 4 and to the consumer 53. The forward movement of the conveying piston 24 ends at the latest when contacting the rear side 2b, i.e. the upper side, of the press plate 2.

[0096] This procedure can be repeated once or several times according to FIGS. 4c and d.

[0097] In a final emptying step, press plate 2 is then lowered until it sits on the bottom 50a of barrel 50, then stopped and the conveying piston 24 is lowered until it sits on the rear side 2b, the top, of press plate 2.

[0098] This empties the barrel, the press plate 2 can be moved upwards out of the barrel 50 and the empty barrel 50 can be changed for a full one.

[0099] In the state of the art as well as in the inventive solution, a spindle nut 25 can be fixed in the frame 1, through which the threaded spindle 15 extends. Each of the two threaded spindles 25 is driven by a separate electric motor 16, whereby the rotations of the two spindle nuts 25, which cause the axial movement of the threaded spindles 15, are mechanically synchronized by a synchronous connection acting between the two spindle nuts 25 and connected to both of them, in particular in the form of a coupling.

[0100] In order to know the respective position of the press plate 2 in the feed direction, a position sensor 21 is arranged on the frame, consisting for example of a sensor strip 21a, which is fastened to the inside of the frame 1, and a position transmitter, for example a position magnet 21b in the case of a magnetostrictive sensor, which is arranged in a vertical position, the sensor strip 21a is moved in the axial direction when the unit consisting of threaded spindles 15, yoke 12, piston rod 17 and press plate 2 is moved downwards along the sensor strip 21a and thus detects the position of the press plate 2, so that press plate 2 can be stopped when it has reached the bottom of barrel 50 and the barrel is emptied.

[0101] The conveyer line 4 which discharges the material is attached to a corresponding connection stub of the yoke 12, so that the conveyer line 4 usually consists of a flexible but high-strength hose which is led away from the rear of frame 1 as shown in FIGS. b and 2.

REFERENCE SIGN LIST

[0102] 1 frame

[0103] 2 press plate

[0104] 2a front side

[0105] 2b rear side

[0106] 3, 3 through opening

[0107] 4 conveyer line

[0108] 5 drive

[0109] 6 enclosure

[0110] 6a housing

[0111] 6b door

[0112] 7 vacuum connection

[0113] 8 vacuum source

[0114] 9 internal space

[0115] 10 axial Direction, Vertical

[0116] 10a press direction

[0117] 10b withdrawal direction

[0118] 11 transverse direction, horizontal

[0119] 12 yoke

[0120] 13 surrounding

[0121] 14 press plate gasket

[0122] 15 threaded spindle

[0123] 16 electric motor

[0124] 17 piston rod

[0125] 18 spring package, energy accumulator

[0126] 19 non-return valve

[0127] 19 passage direction

[0128] 19a ball

[0129] 20 control

[0130] 21a, b position sensor

[0131] 22 press cylinder

[0132] 23 conveying piston seal

[0133] 24 conveying piston

[0134] 25 spindle nut

[0135] 26 clutch

[0136] 50 barrel

[0137] 50a bottom

[0138] 50b peripheral wall

[0139] 52 material

[0140] 53 consumer

[0141] 54 pressure sensor

[0142] 55 position sensor