PUMPING STATION FOR A TANK PUMP

Description

CROSS REFERENCE TO RELATED APPLICATIONS

Applicant claims priority under 35 U.S.C. § 119 of European Application No. 24213104.3 filed on Nov. 14, 2024, the disclosure of which is incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pumping station for a tank pump, preferably for use in the foods industry, chemical industry and/or pharmaceutical industry, comprising a pump tube in which a rotor shaft is accommodated for connecting a rotor that is connected to the rotor shaft to a drive unit.

2. Description of the Related Art

Such a pumping station is already previously known from DE 93 15 773 U1.

Furthermore, reference should be made to DE 32 14 185 A1, CN 214 945 056 U, CN 203 114 704 U, and U.S. Pat. No. 2,832,292 A1.

A further comparable tank pump is already previously known from EP 3 967 883 A1.

Tank pumps essentially consist of a tube and a shaft, which must be at least as long as the tank that they are supposed to empty is high. According to the stated document, a rotor shaft is mounted in a pump tube, so as to rotate in a shaft guidance tube provided specifically for this purpose, without having to be held in position on the rotor side. In particular in the sector of the foods industry, chemical industry and/or pharmaceutical industry, a frequent problem in taking up liquid or viscous media consists in that the pump must be very easy to disassemble for cleaning and, at the same time, must be very light. Alternatively, it must be possible to flush the tank pump as a whole, so that pumping flushing fluid through leads to cleaning even without disassembling the pump, in other words the pump can flush itself. This is problematic, however, since it is difficult or actually impossible to flush the bearings of the pump shaft.

At the same time, it must also be light, since a tank pump is an apparatus that can be manually activated and moved by a user. Therefore no heavy guide elements should be provided in the pump. Furthermore, the mass inertia of the shaft should not become too great, so that it can always still be driven by traditional motors for tank pumps.

SUMMARY OF THE INVENTION

Against this background, the present invention is based on the task of creating a light, easy to disassemble pumping station for a tank pump, which can also be flushed as a whole.

This is accomplished by means of a pumping station for a tank pump in accordance with the characteristics of the invention. Practical embodiments of such an apparatus are discussed below.

In this regard, a pumping station for a tank pump is provided, preferably for use in the foods industry, chemical industry and/or pharmaceutical industry, comprising a pump tube in which a rotor shaft is accommodated for connecting a rotor that is connected to the rotor shaft to a drive unit. According to the invention, such a tank pump is characterized in that the rotor shaft is a tubular hollow shaft, which is produced from a shaft tube that is closed off, on both sides, by end-position connection pieces made of a solid material.

Such a pump has a very stable and twist-resistant shaft that is sealed, for one thing, due to the closure on both sides, and secured to prevent penetration of a conveyed medium, but for another thing is also very twist-resistant, so that it is possible to do without the use of numerous bearings.

It can also happen, in the case of plastic components or sealing rings, that a chemical diffuses into the plastic and is subsequently dissolved out again by a different chemical that reacts with the first or yields a different result than the substance intended to be conveyed. Under chemical influences, crack formation can also come about in materials, which cracks represent a hazard source, since microorganisms that might be located in the cracks can escape effective cleaning and sterilization.

It is also particularly important, in production environments that react sensitively to contamination, that the materials of the pumps do not corrode upon contact with aggressive chemicals. If a material corrodes due to the action of an aggressive cleaning agent or an aggressive substance, the risk exists of chemical residues in the conveyed product.

Furthermore, it is advantageous, in environments with high demands on hygiene, such as clean rooms, if the apparatuses used in such spaces guarantee a long lifetime and reliable operation, since failures that occur in such environments can lead to very long downtimes.

In a concrete embodiment, it appears practical if the end-position connection pieces of the hollow shaft are welded to the shaft tube, and the transitions are preferably made smooth. Because of the strict hygiene regulations that apply to the hollow shaft that comes into contact with the media to be conveyed, sharp edges or notches must be avoided. This prevents germ formation and allows rapid and non-complicated cleaning.

In an advantageous manner, the end-position connection pieces of the hollow shaft and/or of the shaft tube can be configured to be elliptical, in particular round, or polygonal or polygon-like. Depending on the area of application and the cost point, different hollow shaft geometries can be advantageous.

In a concrete embodiment, the end-position connection pieces of the hollow shaft can be shaped identically, and the hollow shaft can have mirror symmetry. This allows easy replacement of a defective component for another; furthermore, the production of hollow shafts is facilitated and simplified, and thereby the resulting costs are reduced.

In a concrete embodiment, the mounting unit, the pump tube, the rotor, as well as the hollow shaft, can be releasably connected to one another, in particular to be releasable without tools, and in this regard can preferably have thread-free, manually releasable quick-release connections. In particular in the foods industry, the chemical industry and/or the pharmaceutical industry, strict hygiene regulations apply to all apparatuses and elements that come into contact with them. In order to prevent the formation of nests or the accumulation of germs, easy cleaning is necessary, and furthermore designs and geometries that are as free of dead spaces as possible should be used, since no place that could make it possible for germs to collect is provided in such designs.

Supplementally, it can be provided that the hollow shaft is mounted so as to rotate in a holding element on the rotor side. In this way, the hollow shaft is fixed in place on a pump foot, and thereby vibration-resistant operation is guaranteed. Furthermore, it can be provided that the holding element is a bearing that forms a cylinder that is flattened off at least on one side, which cylinder has a central passage opening for accommodating the hollow shaft, and preferably adjacent media passages. As a result, the holding element can rotate along, at first, and stabilize the hollow shaft, so that contact of the rotor with an inside wall of the pump tube is prevented, without thereby impairing the conveying operation of the hollow shaft.

Preferably, the holding element can be accommodated on the hollow shaft in a rotation-free manner, and a stop that is preferably welded into or formed in the pump tube can be provided, which stop prevents further rotation of the holding element in the assembled state. As a result, the holding element is held in position during operation of the tank pump. The holding element can therefore easily be removed, and thereby easy cleaning is made possible.

In a further embodiment, the hollow shaft and/or the rotor and/or a pump foot arranged on the pump tube in the end position can be produced from a chemical-resistant, preferably inert material, in particular stainless steel. For a concrete application, many components should be produced from foods-compatible materials that are easy to clean and to disinfect and meet the guidelines of the FDA CFR and EG 1935/2004. Stainless steel or other chemical-resistant inert materials can adhere to these guidelines in a comparatively cost-advantageous manner.

Furthermore, it appears to be advantageous if seals are assigned to the pump tube, for example in the region of the mounting unit, which seals are produced from a chemical-resistant material, preferably from ethylene-propylene-diene rubber or fluorine rubber. This is particularly advantageous if the longest possible useful lifetime of the components being used is preferred. Furthermore, ethylene-propylene-diene rubber and fluorine rubber are crack-resistant materials that do not make any embedding of foreign bodies possible, which bodies could accumulate in such materials over time and form germs.

Furthermore, it appears practical if a sliding-ring seal is provided for sealing between the hollow shaft and a bearing unit arranged on the upper end of the pumping station, and the sliding-ring seal is held in position in the pump tube by means of a steel spring. By means of the sliding-ring seal, undesirable penetration of the conveyed medium into the bearing unit is prevented. In this regard, the seal is pressed upward by means of the steel spring.

Preferably, all contours within the pump tube can have smooth surfaces and smooth connection transitions. All the components that come into contact with the conveyed medium should be designed in such a way that they simultaneously make easy cleaning possible and produce the most laminar volume stream possible, wherein here, too, a design that is as free of dead space as possible can be advantageous.

Furthermore, it appears advantageous if a through-flow counter is assigned either to the pump tube or to an outlet, for a precise amount determination of the volume stream. Precise determination of the conveyed amount of a medium can be extremely advantageous for subsequent evaluation; furthermore, in the case of fully automated industrial processes, a conveyed amount can be set and conveyed precisely, without manual operation being required.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention described above will be explained in greater detail below, using an exemplary embodiment.

The figures show:

FIG. 1 a schematic representation of the tank pump in longitudinal section, as well as

FIG. 2 a schematic representation of the hollow shaft in longitudinal section.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 schematically shows the structure of the pumping station 1 of a tank pump that has a rotor 3 that can be connected to a drive by way of a hollow shaft 4 and, if present, operates the hollow shaft 4 of the pumping station 1. The drive is not shown in the present case.

The pumping station 1 essentially comprises a pump tube 2, which is placed through a bunghole into a tank, also not shown here, and can convey a medium located in this tank. The medium gets into the interior of the pump foot 7 through an opening provided at the bottom in a pump foot 7, and comes into contact with a rotor 3 that is connected, in the end position, to a hollow shaft 4, and builds up a conveying pressure in the pump tube 2 by means of its rotation. The medium is guided up along the pump tube 2 and conducted, by way of a discharge on the side, into a hose or a pipeline, also not shown here. The hollow shaft 4 is passed through the pump tube 2 all the way to a shaft outlet, and connected to a shaft connector 11 that projects beyond the shaft outlet, so as to couple a pump drive, and supported here. A steel spring 9 affixed between the shaft outlet and a fixed stop 12 of the hollow shaft 4 fixes a sliding-ring seal 8 in place in its position, which seal has been affixed between the pump tube 2 and a bearing unit that closes off the pumping station 1 toward the top.

If the hollow shaft 4 is connected to a drive by means of the shaft connector 11, this produces a rotation. During the course of this rotation, the rotor 3 that is connected to the hollow shaft 4 is rotated, and thereby the medium situated in the pump tube 2 is conveyed upward.

The hollow shaft 4 is held in its position, at the lower end, by means of a holding element 10 that is mounted so as to rotate, and thereby a design that can easily be released is provided, in which the individual parts can be connected to one another without tools, and, if applicable, have quick-release connections. This is particularly advantageous for easy cleaning, as it is required in the sector of the foods industry, the chemical industry and/or the pharmaceutical industry. The entire interior of the pumping station 1, in particular the hollow shaft 4 with the rotor 3 and the single holding element 10, which supports the hollow shaft 4 relative to the pump tube 2, can be pulled out of the pump tube 2 and easily cleaned in this way.

FIG. 2 schematically shows the longitudinal section of the hollow shaft 4. End-position connection pieces 6 are welded onto a bend-proof shaft tube 5. The bend-proof shaft tube 5 is a tube having a constant wall thickness. The tube can also be a hollow truncated cone or an elongated hollow body that has a polygon as its base surface. At the ends of the shaft tube 5, the end-position connection pieces 6 have a base surface that agrees with the shaft tube 5 or is slightly recessed, so as to guarantee a stable connection.

The end-position connection pieces 6 are solid and form a narrowing neck having a fixed stop 12. In this regard, they can be shaped to be the same or different.

Furthermore, they have end-position elliptical, in particular round, polygonal or polygon-like connectors, by way of which they can be connected to the rotor 3 or at least indirectly to the drive. The length of the corresponding connection pieces 6 is selected in such a manner that a stop of the hollow shaft 4 is connected to a drive by means of the shaft connector 11. The opposite end-position connection piece 6, which is connected to the rotor 3, can be shaped to be shorter. The connection pieces 6 are welded onto the shaft tube 5 on both sides, and the welding seam is smoothed, in such a manner that a smooth, transition-free surface is formed, in which no nests of dirt can occur, and which are very easy to clean.

What has been described above is therefore a tank pump that is light and easy to disassemble, which can also be flushed as a whole.

REFERENCE SYMBOL LIST

• • 1 pumping station
  • 2 pump tube
  • 3 rotor
  • 4 hollow shaft
  • 5 shaft tube
  • 6 connection pieces
  • 7 pump foot
  • 8 sliding-ring seal
  • 9 steel spring
  • 10 holding element
  • 11 shaft connector
  • 12 stop