Patent Application
20170226995
The invention relates to a peristaltic pump, especially one with a cylindrical pump housing holding a hose lying against the cylinder inner surface and connected at its ends to ports in the end wall or the cylinder inner surface of the pump housing and/or extending at its ends through ports in the end wall or the cylinder inner surface of the pump housing, and with a pump head that flattens the hose by a roller or a sliding shoe.
Pumps for liquids, especially thick materials such as concrete or mortar, must have the largest possible clear cross section in order to keep the flow resistance low. This requires relatively large cross sections for ports in the suction and compression chamber. Valves are somewhat of a hindrance here and cross section changes must be avoided.
High-density solids pumps are known primarily in the form of piston pumps. They are subjected to relatively great wear and are very costly to manufacture. The piston rods of the cylinders additionally need to be cooled in a water tank. Oil and water may form an emulsion in this case. The water needs to be disposed of.
Peristaltic pumps with a pump head rotating steadily in one direction are also used. But since the roller or the sliding shoe disengages from the hose during the output stroke, an enlarged space necessarily results, causing an intense pulsation.
When the roller or the sliding shoe returns, the hose is flattened and a constricted space necessarily results, which also causes a strong pulsation. Strong pulsation means a turbulent output and great wear caused by this. As a result, when the pressure is large, the hose has a short service life. As a rule, two oppositely situated rollers or sliding shoes are used, so that the time from lift-off of the roller to set-down of the roller (idle time) is shortened.
The straightening out of the pump hose after the flattening process is a problem that can be somewhat remedied by special hose materials or a partial vacuum in the housing.
Peristaltic pumps of the kind mentioned above are generally known, e.g., from DE 69700070 T2. The pump described here always rotates in only one direction during output and it comprises several rollers or sliding shoes. A short reversal of direction of rotation occurs only for the shut-down process, in order to lift the rollers off from the hose by means of a special mechanism and prevent its permanent deformation.
DE 10 2004 031 137 [U.S. Pat. No. 7,300,264] also describes a pump rotating in only one direction during output, comprising an arrangement for relieving the hose of the loading by the rollers to prevent a lasting deformation of the hose.
DE 31 48 683 A1 describes a peristaltic pump, but without a cylindrical housing, in which the pump head is driven in reverse, but output of a medium present in the hose occurs only in one of the two directions. In the opposite direction, the roller or the sliding shoe is lifted off from the hose, so that the pump head does not describe the same circular trajectory in both directions, but rather different trajectories.
The problem that the invention proposes to solve is to create a pump, especially a high-density solids pump that has large cross sections, less pulsation, less wear, especially for the pump hose, and that is favorable in its manufacture.
This problem is solved according to the invention in that the peristaltic pump, especially of the kind mentioned at the outset, comprises an oscillating drive, by which the pump head can move along a circular arc alternately back and forth as far as the ports.
Preferably, the roller or the sliding shoe of the pump head flattens the pump hose constantly during output and intake and does not disengage from it. The roller or the sliding shoe remains constantly in contact with the hose. By such a contact is meant not only a simple touching of the hose, but rather the flattening of the hose for purposes of output.
Again preferably, the ports or the associated hose ends each serve alternately as inlet and outlet. The action of the respective port or the respective hose end as inlet or outlet is preferably determined by the position, especially the working position of a diverter valve, especially in combination with the direction of rotation of the pump head.
The pump head pivots in circular manner in both directions on the same trajectory, e.g., at first from left to right, or clockwise, and flattens the pump hose by a roller or a sliding shoe. In this way, the medium in the hose is delivered to one of the ports, e.g., to the right here. Preferably, the pump head has precisely a single roller or a single sliding shoe for the flattening of the hose. This single roller or single sliding shoe is always situated during the pump operation in an angle range that is subtended by the mentioned ports or hose ends. Unlike with conventional peristaltic pumps with rollers turning in only one direction, this roller or sliding shoe thus does not in its movement sweep across the circumferential position at which the respective ports are situated.
The preferably mechanically or hydraulically driven diverter valve pivots in dependence on the direction of rotation and also preferably in dependence on the position of the pump head. It can have a pivot axis parallel to the pivot axis of the pump head that is driven by an oscillating drive on or in the pump housing.
The pump thus delivers in the one direction between port 1 and port 2 and in the second direction between port 2 and port 1. By means of the diverter valve, the output in an output hose connected to a connection piece of the pivoting diverter valve is rectified in that this output hose—depending on the desired output direction—is connected by the diverter valve each time to one of the two ports and this connection is resynchronized in dependence on the direction of rotation of the pump head, especially also the position of the pump head, e.g., preferably when the pump head has reached its particular reversal point on its movement trajectory. Thus, output in both possible rotating directions of the pump head always occurs in the same direction within the output hose that is connected to the diverter valve, and the desired direction is preferably reversible, in particular, the dependency of the diverter valve position on the rotational direction of the pump head can be reversed.
For example, if it is desired to deliver a medium away from the pump, the diverter valve will always be adjusted so that the port to which the roller or the sliding shoe moves is connected across the diverter valve to the output hose. On the other hand, if the pump is required to suction a medium out from the output hose, that port or that hose end [sentence left incomplete in the original]
Thus, the position of the diverter valve and the pivot direction determines whether the pump is suctioning or delivering at the end of the output hose.
The two fixed ports provided in one of the end walls of the cylindrical housing or the hose ends connected to them serve, as described, alternately as inlet and outlet. The ports can also be positioned structurally in another location, e.g., at/in the cylinder inner surface of the pump housing.
In one preferred embodiment, the ports can be formed by the mouths of pipes, e.g., pipes bent at 90 degrees, onto which the hose ends are shoved. In this way, the hose lies entirely inside the housing. The hose thus extends at its ends indirectly, i.e., by means of the preferably bent pipes, through the ports in the end wall or the cylinder inner surface of the pump housing. Such pipes, especially pipes bent at 90 degrees, can extend loosely through the particular port. Thanks to the bending of the pipe from the circumferential direction to the radial or axial direction relative to the housing and the extension of the hose in the circumferential direction of the housing, a fixed connection is obtained between pipe or hose end and port. A pipe, especially one bent at 90 degrees, can also be firmly connected to a respective port in the housing, e.g., by a welded connection or a screw/pin connection.
It can also be provided in one embodiment that the hose itself extends through the ports, i.e., directly at or by its ends. The pump head that flattens the hose by a roller or a sliding shoe, pivots alternately back and forth, each time up to the ports, the hose ends or the (bent) pipes connected to them. Whether the port acts as an inlet or outlet is determined by the position of the diverter valve and the rotation direction of the pump head.
Preferably, the pump head is connected to a central rotation shaft that emerges from one of the end walls of the housing, preferably exiting in the middle and being connected outside the pump housing to a rotary drive unit serving as the drive. Such a drive can be a hydraulic or electric drive. The design as a hydraulic drive especially has the advantage that such a pump can also be mounted as an accessory device on a vehicle, such as farm machinery, and be operated by its hydraulics.
The rotary angle of the pump head is preferably limited at most up to the inlet or outlet port in the end wall or the pipe pieces, preferably the bent pipe pieces, on which the hose is shoved, or depending on the installation position of the diverter valve. The function of inlet and outlet is exchanged during each stroke, preferably when the pump head runs through its reversal point, or dead center.
The mechanical or hydraulic driven diverter valve in a furthermore preferred embodiment is controlled by the position of the pump head. For this, a position detector can be present at each end position, controlling a change in direction of pivoting of the diverter valve and the pump head.
On the diverter valve preferably located on the housing, but on the outside of the housing, there is arranged a coupling, such as a threaded coupling that provides a connection for an output line and each time alternately makes one of the two ports the outlet or, upon reversal, the inlet.
A flexible output hose can be connected to the connection as the output line, delivering the material to a suitable position.
When the hose is flattened, a restraightening into the original condition at the suction side is very important so that the material can be suctioned.
This is accomplished by a special hose material or by a partial vacuum in the pump housing. But this is only possible to a limited extent.
In one possible modification, in the peristaltic pump with oscillating drive and diverter valve it is possible to place in the pump hose, on either side left and right of the flattening site, a shape-stable body such as a ball that has roughly the internal diameter of the hose, i.e., it is somewhat smaller so that it can be moved in the hose. The body then moves in dependence on the pump head, or the roller of the sliding shoe. By the suctioning of the ball, the pump hose is mechanically straightened on the inside and the suctioning is greatly improved.
In another embodiment, two shape-stable bodies, such as rotatable rollers, can be arranged on the outside at two axially opposite sides next to the hose, so that the hose again assumes its original shape after the flattening process. This can occur, for example, in that the bodies press the hose that is broadened at the flattening site, back into its original open hose shape from the outside. Such bodies can be secured, for example, on both sides of the pump head with a distance from the flattening roller or the sliding shoe and move along with it.
On each side of the flattening roller or the sliding shoe there are preferably arranged two such bodies that enclose the pump hose and have a spacing from each other in the axial direction, corresponding to the outer diameter of the hose, especially so that a hose broadened by the flattening is pressed back to its diameter in the axial direction. Insofar as the bodies are designed as rollers, these have a respective axis of rotation that lies radially. The terms “axial” and “radial” are used here in regard to the axis of rotation of the pump motor or the center axis of the cylindrical pump housing.
The level of the material being delivered is always preferably above the level of the mentioned ports that significantly facilitates the suctioning. The walls of a material container can be arranged around the two ports, and preferably the pump housing wall that comprises these ports forms a lower floor of the material container. Thus, material is always above the ports and can be suctioned.
On account of the pivot movement of the pump head and the continual switching between inlet and outlet, at the same time as the constant contact of the roller or the sliding shoe with the pump hose, the peristaltic pump according to the invention with an oscillating drive and a diverter valve runs extremely low in vibration and free of jolting. The service life of the pump hose is thereby increased.
In order to facilitate the mounting of the new pump hose when it is necessary to replace the pump hose, the invention provides an arrangement as the mounting accessory, whereby a pump hose, especially one having an angular extension of less than 360 degrees between its ends, is placed on a ring, especially a closed ring, and secured on it, especially at least in the region of its ends, e.g., by belts or other ties. When it is necessary to replace the pump hose, this mounting accessory after removing the old hose can be placed in the pump housing and then the ring is removed. Thus, the installer is freed from the very strenuous labor of bending the stiff hose with large diameter in order to adapt it to the pump housing.
The invention can also provide the using of hose pieces as the pump hose that already have an imprinted curvature, corresponding at least substantially to the pump housing diameter. Such hose pieces can be fabricated, e.g., by arranging the material of the hose, especially fabric layers and rubber material, on a production mandrel curved at least into a partial circle.
Preferably, the production mandrel in its at least partial circular curvature has an outer diameter that corresponds at least substantially to the diameter of the pump housing at the inner wall against which the pump hose rests during operation, minus the wall thickness of the hose. The material arranged on the curved production mandrel is then vulcanized into the finished hose, then having this precise curvature and being able to be installed virtually free of stress inside the pump housing. The curved production mandrel has a preferably circular cross section, corresponding in its diameter to the later internal diameter of the finished pump hose.
The invention can provide that a torque greater than 10,000 Newton-meters can be generated with the drive motor of the pump head. The drive motor can drive the pump head across a planetary gearing.
Furthermore, the pump hose can have a rated width larger than 50 mm, preferably larger than 75 mm, even more preferably larger than 100 mm. The pump hose can have a wall thickness greater than 20 mm, especially one with at least 4 fabric inlays. The pump housing can have an outer diameter larger than 500 mm, preferably larger than 800 mm, even more preferably larger than 1000 mm.
In the following, preferred sample embodiments of the invention shall be explained more closely with the aid of the enclosed drawings in which.
A pump housing 1 comprises substantially a cylindrical wall 2 and a circular end wall 3. In the end wall 3 are situated the ports 4 that serve as inlet and outlet, depending on the position of the diverter valve 5.
In
Moreover, a roller or sliding shoe 8 extends between the driving core 6 and the cylindrical wall 2, flattening the pump hose 9 in back and forth manner and forming a suction or compression chamber depending on the direction of rotation; in dependence on the position of the diverter valve 5.
The roller or the sliding shoe 8 always remains in contact with the pump hose 9 and forms a separation point between the suction and compression chamber; this is determined by the position of the diverter valve 5 and the rotation direction of the pump head 7.
In the end wall 3 there are two ports 4 and 12 with a circular cross section. The port 4 or 12 freed up by the diverter valve 5 serve as the material inlet during normal operation.
In
The pivot axis of the diverter valve 5, looking radially, lies between the pivot axis of the pump head 7 and the ports 4/12 and it has a circumferential position lying between the ports 4/12.
A reversed pump mode can also be realized, in which the function of the ports 12 and 4 is interchanged; now, the thick material is suctioned in through the port covered by the diverter valve 5 that normally serves as a discharge line for the thick material, and the material emerges through the port not covered. This is accomplished by a changing of the dependency of the diverter valve position on the rotation direction of the pump head 7. Thus, by inverting the dependency, the pump operation can be reversed.
The pins 16 serve as a pivot point of the pump housing 2, and in this way, the pump housing or the entire unit can be pivoted by hand. The cleaning and maintenance of the pump is always done in a user-friendly position. In this way, a complete emptying and cleaning of the pump is possible, with no additional cleaning ports.
In
In
On the other hand,
For the pivoting of the pump head, a hydraulic pivot motor or a gear motor would be the best variant, since it is compact and theoretically can work in the medium. Large forces can also be achieved. This also allows the peristaltic pump with an oscillating drive and a diverter valve to work in water, for example.
For smaller peristaltic pumps with oscillating drive and a diverter valve, electric drives are also possible, of course.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202016000790 | Feb 2016 | DE | national |
