EP0130374A2 - Flexible tube pump - Google Patents

Abstract

A stricture pump (30) comprising a casing (31) containing a delivery hose (32), a rotor (33) and a band-like dividing member (34) which is substantially stable in respect of length, and which is fastened to a fastening part (53, 55, 57) outside the outermost periphery of the rotor, in such a manner as to be fixed to the casing, and in addition is disposed around the rotor. Together with the casing walls, the dividing member closes off sealingly a suction chamber (38.1). On the rotation of the rotor, this closed-off suction chamber is increased in size, whereby a negative pressure is produced in it. Fluid is thereby forced from a suction branch (45) into that portion of the hose which lies within the suction chamber. On the further rotation of the rotor, the fluid drawn in is pressed out of the hose by rollers (52) on the rotor, these rollers pressing by way of the dividing member (34) against the hose disposed between the dividing member and the peripheral wall (37) of the casing. The hose has substantially no restoring power of its own, and therefore draws in fluid not through its own restoring power but through the negative pressure in the suction chamber. A stricture pump of this kind can be operated at a very high speed of rotation, so that high output can be achieved.

Description

TECHNICAL AREA

The invention relates to a peristaltic pump in which a rotor rotates in the interior of a housing in the direction from a suction chamber to a pressure chamber and presses on a hose laid between a suction nozzle and a pressure nozzle along a peripheral wall of the housing.

STATE OF THE ART

In the most widely used hose pumps, the hose is designed in such a way that it has a high resilience in order to return to its shape after being pressed together by the rotor, even under strong negative pressure, and thus to suck up fluid. In order to be able to achieve high suction negative pressures, the hose must be very stiff, which results in a high force required for compressing it, and thus in a pump that is heavy and bulky. The speed of the rotor can only be very low since the hose takes a relatively long time to return from its crimped state to its original state. This flexing work against large forces requires a high output to deform the hose, which also heats up relatively strongly due to the deformation work.

In the case of a peristaltic pump, these disadvantages are circumvented with a hose which essentially does not have its own resilience. The resetting of the hose after it is pressed together is accomplished by that there is negative pressure in the entire pump housing. The vacuum is continuously maintained by a vacuum pump connected to the housing. This pump has the advantage that the runner can run much faster, since the existing vacuum straightens up the compressed hose immediately by drawing in further fluids after the runner has moved on. The flexing power to be applied is considerably lower, so that the hose also heats up considerably less and therefore wears less. However, this pump has the disadvantage that an additional vacuum pump is required, which in turn makes the overall structure difficult and expensive. On the pressure side, the hose must be compressed against the force by the negative pressure, which is a useless workload.

PRESENTATION OF THE INVENTION

The invention has for its object to provide a peristaltic pump that is simple and lightweight.

The invention is given by the features of claim 1. Advantageous refinements are the subject of dependent claims. The features of the subclaims can be used in any combination with one another insofar as they are not obviously mutually exclusive.

In addition to a rotor and a hose in a housing, the hose pump according to the invention also has a band-shaped, substantially length-stable separating part, which is fixed to the housing in the interior of the housing between the pressure chamber and suction chamber on a fastening part outside the outer circumference of the rotor and is otherwise placed around the rotor . The separating part is at least so wide in its suction space section that it is on the rear forehead wall and abuts the front wall of the housing and thus seals the suction chamber section. For better sealing, there is still a barrier liquid in the interior of the housing. The rotor rotating in the held separating part moves the separating part back and forth so that the suction space is alternately enlarged and reduced. When enlarging, a negative pressure occurs, which expands the hose, which was initially compressed by a squeeze body of the rotor, so that the fluid to be pumped is pressed down. The hose has essentially no resilience.

The pump according to the invention thus generates the negative pressure for expanding the hose itself, so that an additional vacuum pump is not required. The pump differs from conventional peristaltic pumps by the additional separating part, the additional sealing liquid and the flaccid hose used. A pump for a delivery rate of around 30,000 l / h weighs only around 30 kp, while a conventional peristaltic pump for the same delivery rate weighs fifteen times and a peristaltic pump with an additional vacuum pump weighs around five times. The pump runs at about 400 RPM while a conventional pump runs at about 30 to 100 RPM.

BRIEF DESCRIPTION OF THE DRAWINGS

• Fig. 1 - 3 einen Längsschnitt, einen Querschnitt und eine Draufsicht auf eine Grundausführungsform;
• Fig. 4 - 8 Querschnitte durch verschiedene Schläuche;
• Fig. 9 - 11 Ausführungsformen von Anschlußstutzen für ovale Schläuche;
• Fig. 12 - 14 Schnitte durch Ausführungsformen von Trennteilen;
• Fig. 15 einen Querschnitt durch einen Deckel mit nachgiebigem Wandbereich;
• Fig. 16 einen Längsschnitt gemäß Fig. 1, jedoch durch eine Pumpe mit Pulsationsdämpfern und einem Schnüffelventil;
• Fig. 17 - 20 Schnitte durch eine Pumpenauflage mit einstellbarem Auflagedruck;
• Fig. 21 - 23 Schnitte durch eine Pumpe gemäß Fig. 1, jedoch mit sekundärer Schlauchpumpe.

The invention is explained in more detail with reference to exemplary embodiments according to the following figures. Show it:

• Figures 1-3 show a longitudinal section, a cross section and a plan view of a basic embodiment.
• Fig. 4 - 8 cross sections through different hoses;
• Fig. 9 - 11 embodiments of connecting pieces for oval tubes;
• 12 - 14 sections through embodiments of separating parts;
• 15 shows a cross section through a cover with a flexible wall area;
• 16 shows a longitudinal section according to FIG. 1, but through a pump with pulsation dampers and a snifting valve;
• Fig. 17 - 20 sections through a pump support with adjustable contact pressure;
• 21-23 sections through a pump according to FIG. 1, but with a secondary peristaltic pump.

WAYS OF CARRYING OUT THE INVENTION

The peristaltic pump 30 of the exemplary embodiment according to FIGS. 1-3 has a housing 31 as main components and, in the interior thereof, a delivery hose 32, a runner 33 and a separating part 34.

The housing 31 has approximately the shape of a cylindrical disk with a rear end wall 35, a front wall formed from a front end wall 36 and a cover 43 and a peripheral wall 37, through which walls an interior 38 is enclosed.

The upper section of the circumferential wall 37 is flat, and two nozzles are inserted into this section, of which the left one is called the suction nozzle 45 and the right one is called the pressure nozzle 46. Which spigot acts as a suction spigot and which acts as a pressure spigot depends on the direction of rotation of the rotor 33. The hose 32 is fastened to the two connecting pieces 45 and 46 with hose clamps 47 so that they can be replaced easily. The hose 32 is laid along the peripheral wall 37.

The rotor 33 is mounted in a bearing housing 39 which is connected to the rear end wall 35. The bearing housing can also be missing if the rotor is placed directly on the shaft of a drive motor. The rotor 33 is triangular, each with a pair of rollers 52 at the corner points.

Around the rotor 33, the separating part 34 is placed, which is firmly connected to the housing 31 in that it is stretched between a fastening rib 53 on the housing and a clamping body 55 which can be tightened by a clamping screw 57. The clamping body 55 is rounded so that it cannot kink even when it moves back and forth. As can be seen from FIG. 2, the width of the separating part 34 is selected such that it bridges the distance between the rear end wall 35 and the cover 43. The separating part 34 is band-shaped and essentially stable in length.

In its lower section, which is opposite the flat connecting piece region of the peripheral wall 37, the peripheral wall 37 is designed in the shape of a circular cylinder, the central axis of this circular-cylindrical pump section coinciding with the central axis of the rotor 33. The pump section extends over at least half a circular cylinder. An elastic pad 48 is applied to the pump section of the peripheral wall 37. The thickness of the support 48 is dimensioned such that the hose 32 is then pushed completely between the separating part 34 and the support 48 when a pair of rollers 52 runs inside the separating part 34 along the pump section.

In the interior despehäuses, in particular in the space enclosed by the partition member 34 space is a (not shown) _S pe _r r _fl superfluous _k eit present. This is filled through a filler hole with filler screw 87 in the cover 43 until the liquid escapes at the location of a screwed-out control screw 88 in the middle of the cover. Then the control screw 88 and the filler screw 87 are screwed in again.

The function of the pump according to FIGS. 1-3 is now explained in more detail using the flow diagrams according to FIGS. 4.1-4.4. It is assumed that the rotor 33 rotates counterclockwise, that is to say in the direction of the arrow 64 in FIG. 1. In the position shown in FIG. 4.1, the rotor has rotated so far that one of its pairs of rollers 52, which is referred to below as the first pair 52.1, just squeezes the hose part coming from the suction port 45 completely. A part of the interior 38 is then separated by the housing walls and the separating part 34, which is referred to below as the suction space 38.1. A suction chamber 63.1 is formed in the hose 34 between the suction nozzle and the squeezing point. The hose 32 is squeezed off at a further point by the pair of rollers 52.2 following in the direction of rotation. The chamber enclosed by the hose between this second squeezing point and the pressure port 46 is referred to below as the pressure chamber 63.2. The of the space surrounding the housing walls and the separating part 34, which is connected to the ambient air via a ventilation opening 93 in the flat section of the peripheral wall 37, is referred to below as the pressure space 38.2. The volume enclosed by the hose between the first pair of rollers 52.1 and the second pair 52.2 is referred to as the intermediate chamber 63.3. The volume of this intermediate chamber remains unchanged when the rotor is turned.

The rotor rotates counterclockwise and then takes
4.2, the volume of the suction space 38.1 has increased. Since this space is sealed off by the housing walls and the separating part 34, a negative pressure has developed in it. This negative pressure causes the substantially flaccid hose is abgebläht by nachrückendes fluid 32, therefore, the Vo _- lumen of the suction chamber 63.1 is increased. At the same time, the volume of the pressure chamber 63.2 has decreased due to the second pair of rollers 52.2 rolling along the peripheral wall in the direction of the pressure port 46. The pump has therefore sucked in fluid 45 via the suction nozzle and dispensed fluid 46 via the pressure nozzle.

When turning further, the position shown in FIG. 4.3 is finally reached, in which the second pair of rollers 52.2 stands just before lifting off the peripheral wall, and the third pair of rollers 52.3 starts to press the hose again in the area of the suction chamber 63.1. In the position according to FIG. 4.4, only the first pair of rollers 52.1 is in contact with the peripheral wall, so that no intermediate chamber 63.3 is closed. The pump is close to the initial state according to FIG. 4.1, but when it is reached the third pair of rollers 52.3 takes over the function of the pair of rollers 52.1 according to FIG. 4.1.

On the pressure side, the hose pump 30 thus acts like a conventional hose pump, in which fluid is pressed out of a hose by a squeeze body. On the suction side, however, the pump 30 functions in such a way that, with the help of the separating part 34, it forms a suction space 38.1 that increases when the rotor 33 rotates, in which the pressure drops further and further, so that it finally becomes lower than the pressure in the suction chamber 63.1 of the delivery hose 32, whereby fluid to be pumped is pressed into the suction chamber 63.1.

For the function of the pump, the vacuum-tight seal between the separating part 34 and the rear end wall 35 and the cover 43 is essential, for which purpose the sealing liquid mentioned at the beginning inside the separating part 34 is used. However, this barrier liquid is partially sucked into the suction space 38.1 and reaches the pressure space 38.2 when the rotor 33 is rotated. So that the barrier liquid then returns to the space enclosed by the separating part 34, the pump 30 has a transfer opening 85 in the housing cover in the area of the pressure chamber 38.2, a further transfer opening 86 in the middle of the cover and a transfer channel 81 connecting the two openings. Wing-shaped ribs 78 are provided on the rotor 33, which inject the reintroduced barrier liquid onto the inside of the separating part 34 so that the barrier liquid can again perform its sealing function there.

To change a hose 32, the barrier liquid is removed by opening the cover 43 by removing screws 89
taken, the hose clamps 47 are loosened, the worn hose is removed, and then it is attached a new hose in reverse order. The cover can then be replaced with a 90 ° offset if the pump is to be used in a different direction of rotation, i.e. clockwise. By turning the cover it is ensured that the transfer channel 81 again establishes the connection between the pressure space 38.2 and the middle space. The rotated position is shown in dash-dot lines in FIG. 3, as are the directions of the pumped fluid in dash-dot lines.

The conveyor hose 32 is, for. B. a normal plastic hose. However, it can also be formed by a stable textile outer skin 66 with a plastic inner coating 67 which is resistant to the fluid to be pumped (FIG. 5). The conveying hose 32 can also consist of a textile outer hose 68, which essentially absorbs the negative pressure forces that occur, and a less stable, resistant inner hose 69 (FIGS. 6, 7). The hoses are advantageously each connected to fittings by means of hose clamps in such a way that they can be detached from the fittings and thus replaced without opening the pump cover.

It should be noted that with a peristaltic pump the greatest forces are exerted on the tube at its squashed edges. It is therefore proposed to use a tube preformed in the crimped form. The bending of the tube then extends essentially over its entire circumference, so that the strongly curved area is less stressed than in the opposite case, where a circular tube is to be squeezed at the narrowly defined limits. In any case, the circumference of the hose should be such that it is not greater than twice the distance between the rear end wall 35 and the cover 43, so that the hose can lie flat on the support 48 in the crimped state without folds. An embodiment of a flat tube consists of two surface webs 72, which with their respective surfaces provided with a coating 74 are placed one on top of the other and are connected to one another in their edge regions 75 by a seam 77. However, a one-piece pre-formed plastic tube is even more advantageous. Hose nozzles 95 adapted to the hose shape are advantageously used to connect such flat hoses to the suction nozzle 45 or the pressure nozzle 46 (FIGS. 9-11).

So that the separating part 34 seals well against the rear end wall 35 and the cover 43, it is advantageously provided with a sealing lip 101 and 102 on its two longitudinal edges 99 and 100 (FIG. 12). The sealing lips can be designed so that they seal only on one side or on two sides. Sealing on one side, namely from the higher pressure in the interior to the lower pressure in the suction space 38.1, is generally sufficient.

So that the separating part squeezes onto the hose 32 as flexibly as possible, it is advantageously provided with an elastic support 109 on its outside 108. The separating part itself advantageously has a reinforcing insert. It is advantageously formed on its inside with a transverse corrugation, which contributes to the fact that barrier liquid is distributed evenly without sliding effect between the rollers 52 and the separating part 34 along the separating part. Instead, the rollers 52 can also have cross corrugation. If instead of rollers 52 sliding squeeze bodies are used, it is advantageous to use a separating part 34 without corrugation so that these sliding bodies slide on a barrier liquid film on the separating part. The separating part 34 has no elastic Pad 109, but if the pad 48 on the peripheral wall 37 is sufficiently elastic, it is advantageous to apply a cross corrugation 97 on the outside 108 of the separating part 34, as shown in FIG. 1. This cross corrugation leads to the fact that the hose between the support 48 and the roller 52 with the intervening separating part 34 is pressed off at several points, so that a multiple seal against backflow of fluid from the intermediate chamber 63.3 of the hose 30 is ensured. The separating part can also be made narrower in the area of the pressure space 38.2 than in the area of the suction space 38.1, since it is no longer necessary to form a closed volume in the pressure space. A narrowing part 34 in the pressure chamber section also ensures that barrier liquid conveyed into the pressure chamber can easily enter the space surrounded by the part 34 again.

To change the width of the separating part when heated, e.g. B. when pumping hot liquids, it is advantageous to design the cover 43 in multiple layers, namely with an elastic intermediate layer 116 and a metal plate 115 on which the separating part 34 slides (Fig. 15).

In the embodiment according to FIG. 16, the suction space 38.1 is connected to a vacuum gauge 136. There is also a snifting valve 123 with an adjusting device 136, which allows air to pass from the pressure chamber 38.2 into the suction chamber 38.1 through a through opening 131. This allows the vacuum in the suction chamber 38.1 and thus the suction height of the pump to be set. There are also two pulsation dampers 137, one each close to the connecting piece and the suction piece. Each pulsation damper 137 consists of a molded body which is connected to the outside air via a feed line 141.

With every peristaltic pump there is a desire to be able to stop pumping despite the rotating rotor. In the case of a pump according to the application, this can be achieved either by the adjusting device 135, as already described, or by an embodiment, as will now be explained with reference to FIGS. 17-20. In this embodiment, there is an inflatable pad 48. The inflation takes place via line-shaped cavities 146 in the support. If the pad 48 is heavily inflated, the tube 32 between it and the separating part 34 is squeezed out completely at the location of a roller 32. If, however, the pad 48 is only slightly or not at all inflated, the hose is no longer squeezed sufficiently, as a result of which liquid can flow back from the pressure side to the suction side and thus the pump no longer delivers. In the embodiment shown, the cavities 146 are closed on one side by a sealing plug 147, while on the other side compressed air is supplied from a pressure accumulator 157 to each conduit-shaped cavity 146 via a collecting tube 152 and individual tubes 151. This receives compressed air via a pressure reducing valve 155 and a shut-off valve 156.

The compressed air required to inflate the support 48 according to the embodiment of FIGS. 17-20 can itself be obtained with a hose pump 30 designed according to FIGS. 21-23. This peristaltic pump has a secondary peristaltic pump 177 with a secondary delivery hose 178, which is laid along the inside of the separating part 34 from a secondary suction port 181 to a secondary pressure port 182. There is one in each of the rollers 52 Circumferential groove 179 recessed through which the secondary conveyor hose 178 is guided. However, the groove is only so deep that the squeezed secondary delivery hose 178 has its place. Air flows from the secondary pressure port 182 through a connecting line 176 into a wall part 175, in which the air is introduced through through openings 174 into individual line-shaped cavities 146 of the support 48. The pressure of the air can be adjusted by a valve 189 with adjusting screw 196. The end of the support 48 located on the pressure side is designed as a pulsation damper 137 in the embodiment according to FIG. 21.

In all pumps, instead of a closed band, an open band can also be used as the separating part 34, which is firmly attached to the housing 31 at both ends. Instead of rollers, any squeeze body can be used, even those that only slide, i.e. do not roll, whose axes are parallel and concentric to the rotor axis.

In the case of pumps according to the invention, the quantity which can be conveyed can also easily be changed by replacing hoses which each have different cross sections. It is only necessary to ensure that the outer circumference of the tube corresponds at most to twice the distance between the two planar boundary walls. Such adjustment of the delivery rate through the use of hoses with different cross-sections is not possible with conventional peristaltic pumps, since the entire pump construction is adapted in terms of depth and diameter to the diameter of a specific hose.

In principle, the pump already works with a single squeeze body rotating inside the separating part. However, at least two bodies are present for practical purposes. Three or four squeeze bodies are advantageously used.

Claims (12)

1. Peristaltic pump with - A housing (31) with a peripheral wall (37) which is circular cylindrical at least in a pump section which connects a suction chamber (38.1) with a pressure chamber (38.2) in the housing, - a flat rear end wall (35) which closes the housing on its rear, - a flat front wall (36, 43) which closes the housing on its front, - A suction nozzle (45) through which the fluid to be pumped is sucked into the suction chamber and - a pressure port (46) through which the fluid is pressed out of the pressure chamber, a rotor (33) rotating in the interior (38) of the housing in the direction from the suction chamber to the pressure chamber, - whose rotor axis coincides with the cylinder axis of the pump section, and - The at least one squeeze body (52), and a hose (32) which is laid between the suction nozzle (45) and the pressure nozzle (46) along the peripheral wall (37), - whose circumference corresponds at most to twice the distance between the rear end wall (35) and the front wall (43), and - who essentially has no own resilience,
characterized in that - The rotor (33) has at least two squeeze bodies (52) with concentric squeeze body body axes parallel to the rotor axis, - A band-shaped, substantially length-stable separating part (34) is present, which is fixed to the housing in the interior (38) between the pressure chamber (38.2) and the suction chamber (38.1) on a fastening part (53, 55, 57) outside the outermost part Rotor circumference is attached and is otherwise placed around the rotor, and at least in its suction chamber section has a width such that when the rotor rotates, it is sealed at least with its suction chamber section against the rear end wall (35) and the front wall (36, 43). and is pushed here, whereby the suction chamber is separated from the pressure chamber in a vacuum-tight manner, - The hose (32) lies between the inner wall of the pump section and the separating part, and - In the interior (38) of the housing (31) there is a barrier liquid. 2. Pump according to claim 1,
characterized in that the tube (32) has an elongated cross-sectional shape and is arranged such that the long axis of the cross-section lies parallel to the peripheral wall (37). 3. Pump according to claim 1,
characterized by a secondary hose pump (177) with at least one delivery hose (178) which is laid on the inside of the separating part (34). 4. Pump according to claim 1
characterized in that the suction space communicates with an adjustable air inlet valve (123). 5. Pump according to claim 1,
characterized in that there is a connection (81, 82, 85, 86) between the pump chamber and the interior surrounded by the separating part (34), which allows the sealing liquid to pass from the pump chamber into the interior. 6. Pump according to claim 1,
characterized in that the Front wall is formed by an annular front end wall (35) which attaches to the peripheral wall (37) and a cover (43) which closes the opening left free by the annular end wall. 7. Pump according to claim 1,
characterized in that the separating part (34) has a sealing lip (101, 102) on each of its two longitudinal edges (99, 100). 8. Pump according to claim 1,
characterized in that the separating part (34) has a transverse corrugation (97) on its outer side facing the peripheral wall (37). 9. Pump according to claim 1,
characterized in that the separating part (34) has transverse corrugation on its inside. 10. Pump according to claim 1,
characterized in that there is a support (109) on the outside of the separating part (34). 11. Pump according to claim 1,
characterized in that an elastic support (48) is provided on the pump section of the peripheral wall (37). 12. Pump according to claim 11,
characterized in that the elastic support (48) has inflatable cavities (146), by pumping up the pressure of the hose (32) between the separating part (34) and support can be adjusted.

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