Pump unit for a container pump

Abstract

Container pumps used for conveying food products are subject to stringent design requirements. A particular challenge lies in the fact that the liquid is located both inside and outside the pipe. The pump must be easy to clean, either by flushing or simple disassembly, which complicates the design. Therefore, bearings for the shaft can only be used at its ends. To support a long shaft only at its ends, it must be very rigid yet lightweight, as the container pump is operated manually. The shaft's moment of inertia must not be too high to allow it to be driven by conventional motors. To achieve a shaft that is both lightweight and rigid, a hollow shaft is used. This consists of a shaft tube with solid end fittings welded to its ends.

Description

[0001] The present invention relates to a pumping station for a container pump, preferably for use in the food industry, chemical industry and / or pharmaceutical industry, comprising a pump tube in which a rotor shaft is received for connecting a rotor connected to the rotor shaft with a drive unit.

[0002] Such a container pump is already known from EP 3 967 883 A1. Container pumps essentially consist of a tube and a shaft, which must be at least as long as the height of the container they are intended to empty. According to the aforementioned document, a rotor shaft is rotatably mounted in a specially designed shaft guide tube within a pump tube, without requiring any holding in position on the rotor side. Particularly in the food, chemical, and / or pharmaceutical industries, a common problem when handling liquid or viscous media is that the pump must be very easy to disassemble for cleaning and, at the same time, very lightweight. Alternatively, the entire container pump should be flushable, so that even without disassembling the pump, pumping through it with rinsing fluid results in cleaning, i.e., the pump can self-clean.However, this is problematic because it is difficult or even impossible to flush the bearings of the pump shaft.

[0003] At the same time, it must also be lightweight, since a container pump is a device that is manually operated and moved by a user. Therefore, no heavy guide elements should be incorporated into the pump. Furthermore, the shaft's moment of inertia must not be too high so that it can still be driven by conventional motors designed for container pumps.

[0004] Against this background, the present invention aims to create a lightweight, easily disassembled pumping unit for a container pump that can also be rinsed as a whole.

[0005] This is achieved by a pumping station for a container pump according to the features of independent claim 1. Useful embodiments of such a device can be found in the subsequent dependent claims.

[0006] The invention provides a pumping unit for a container pump, preferably for use in the food, chemical, and / or pharmaceutical industries, comprising a pump tube in which a rotor shaft is housed for connecting a rotor connected to the rotor shaft to a drive unit. According to the invention, such a container pump is characterized in that the rotor shaft is a tubular hollow shaft made from a shaft tube which is closed at both ends by end connectors made of solid material. Such a pump has a very stable and torsionally rigid shaft which, firstly, is leak-proof due to the closure at both ends and is secured against the ingress of a pumped medium, and secondly, is also very torsionally rigid, so that the use of numerous bearings can be dispensed with.

[0007] It can also happen with plastic components or sealing rings that a chemical diffuses into the plastic and is later dissolved by another chemical that reacts with it or produces a different result than the intended substance. Chemical influences can also cause materials to crack, which poses a hazard because microorganisms potentially present in the cracks can evade effective cleaning and sterilization.

[0008] Even in production environments sensitive to contamination, it is particularly important that pump materials do not corrode when in contact with aggressive chemicals. If a material corrodes due to exposure to an aggressive cleaning agent or other aggressive substance, there is a risk of chemical residues in the pumped product.

[0009] Furthermore, in environments with high hygiene requirements such as cleanrooms, it is advantageous if the equipment used in such rooms ensures durable and reliable operation, as failures occurring in such environments can lead to very long downtimes.

[0010] In a specific design, it seems advisable to weld the end connecting pieces of the hollow shaft to the shaft tube and preferably to smooth the transitions. Due to the strict hygiene requirements for the hollow shaft, which comes into contact with the conveyed materials, sharp edges or indentations must be avoided. This prevents bacterial growth and allows for quick and easy cleaning.

[0011] Advantageously, the end connecting pieces of the hollow shaft and / or the shaft tube can have an elliptical, particularly round, or polygonal or polygonal cross-section. Depending on the application and cost, different hollow shaft geometries may be advantageous.

[0012] In a specific embodiment, the end connecting pieces of the hollow shaft can be identically shaped, and the hollow shaft can be mirror-symmetrical. This allows for easy replacement of a defective component with another, and also simplifies the manufacturing of hollow shafts, thereby reducing the associated costs.

[0013] In a specific embodiment, the bearing unit, the pump tube, the rotor, and the hollow shaft can be detachably connected to one another, particularly without tools, and preferably feature threadless, manually releasable quick-release connections. Especially in the food, chemical, and / or pharmaceutical industries, strict hygiene regulations apply to all devices and components that come into contact with these industries. Easy cleaning is necessary to prevent the formation of pockets or the accumulation of germs; furthermore, designs and geometries with as few dead spaces as possible should be used, since such designs do not provide any space that could allow germs to accumulate.

[0014] Additionally, the hollow shaft can be rotatably mounted in a retaining element on the rotor side. This fixes the hollow shaft to a pump base, ensuring vibration-resistant operation. Furthermore, the retaining element can be a bearing forming a cylinder that is flattened on at least one side and has a central through-opening for receiving the hollow shaft and preferably adjacent media passages. This allows the retaining element to rotate with the hollow shaft and stabilize it, preventing the rotor from contacting an inner wall of the pump tube without impairing the pumping operation of the hollow shaft.

[0015] Preferably, the retaining element can be mounted on the hollow shaft without rotation, and a stop, preferably welded or molded into the pump tube, can be provided to prevent further rotation of the retaining element in the assembled state. This keeps the retaining element in position during operation of the tank pump. The retaining element can thus be easily removed, facilitating simple cleaning.

[0016] In a further embodiment, the hollow shaft and / or the rotor and / or a pump base arranged at the end of the pump tube can be made of a chemically resistant, preferably inert, material, in particular stainless steel. For a specific application, many components should be made of food-grade materials that are easy to clean and disinfect and comply with the FDA CFR and EC 1935 / 2004 guidelines. Stainless steel or other chemically resistant inert materials can meet these guidelines at a comparatively low cost.

[0017] Furthermore, it appears advantageous if the pump tube, for example in the area of ​​the bearing unit, is fitted with seals made of a chemically resistant material, preferably ethylene propylene diene monomer (EPDM) rubber or fluorocarbon rubber. This is particularly advantageous when the longest possible service life of the components used is desired. Moreover, EPDM and fluorocarbon rubber are crack-resistant materials that do not allow the incorporation of foreign matter, which could accumulate over time and form nuclei.

[0018] Furthermore, it seems advisable to provide a mechanical seal between the hollow shaft and a bearing unit located at the upper end of the pumping unit, and to hold the mechanical seal in position within the pump tube by means of a steel spring. The mechanical seal prevents unwanted ingress of the pumped medium into the bearing unit. The steel spring pushes the seal upwards.

[0019] Preferably, all contours within the pump tube should have smooth surfaces and smooth transitions. All components that come into contact with the pumped medium should be designed to allow for easy cleaning while simultaneously generating the most laminar flow rate possible; here, too, a design with as few dead spaces as possible can be advantageous.

[0020] Furthermore, it appears advantageous to equip either the pump pipe or an outlet with a flow meter for precise measurement of the volumetric flow rate. Accurate measurement of the pumped quantity of a medium can be extremely beneficial for subsequent analysis; moreover, in the case of fully automated industrial processes, a flow rate can be precisely set and delivered without the need for manual operation.

[0021] The invention described above will be explained in more detail below using an exemplary embodiment.

[0022] They show Figure 1 is a schematic representation of the container pump in a longitudinal section, and Figure 2 is a schematic representation of the hollow shaft in a longitudinal section.

[0023] Figure 1Figure 1 schematically shows the structure of pumping unit 1 of a tank pump, which has a rotor 3 that can be connected to a drive via a hollow shaft 4 and which, if present, drives the hollow shaft 4 of pumping unit 1. The drive is not shown here.

[0024] The pumping station 1 essentially comprises a pump pipe 2, which is inserted through a bung hole into a container (not shown) and can pump a medium located in this container. The medium enters the interior of the pump base 7 through an opening provided at the bottom of the pump base 7 and comes into contact with a rotor 3, which is connected at its end to a hollow shaft 4. The rotor's rotation generates a delivery pressure in the pump pipe 2. The medium is conveyed up the pump pipe 2 and through a lateral outlet into a hose or pipe (also not shown). The hollow shaft 4 extends through the pump pipe 2 to a shaft outlet and is connected to a shaft connection 11, which projects beyond the shaft outlet, for coupling a pump drive and is supported there.A steel spring 9, located between the shaft outlet and a fixed stop 12 of the hollow shaft 4, secures a mechanical seal 8, located between the pump tube 2 and a bearing unit closing off the pumping unit 1 at the top, in its position.

[0025] When the hollow shaft 4 is connected to a drive via the shaft connection 11, this generates a rotation. During this rotation, the rotor 3 connected to the hollow shaft 4 is turned, thereby pumping the medium located in the pump tube 2 upwards.

[0026] The hollow shaft 4 is held in position at its lower end by a rotatably mounted retaining element 10, resulting in a design that can be easily disassembled. The individual parts can be connected without tools and may optionally feature quick-release connections. This is particularly advantageous for easy cleaning, as required in the food, chemical, and / or pharmaceutical industries. The entire interior of the pump unit 1, especially the hollow shaft 4 with the rotor 3 and the single retaining element 10 that supports the hollow shaft 4 relative to the pump tube 2, can be pulled out of the pump tube 2 and thus easily cleaned.

[0027] Figure 2Figure 1 schematically shows the longitudinal section of the hollow shaft 4. End connectors 6 are welded to a rigid shaft tube 5. The rigid shaft tube 5 is a tube with a constant wall thickness. The tube can also be a hollow truncated cone or an elongated hollow body with a polygonal base. At the ends of the shaft tube 5, the end connectors 6 have a base that is either identical to or slightly recessed in the shaft tube 5 to ensure a stable connection.

[0028] The end connecting pieces 6 are solid and form a tapered neck with a fixed stop 12. They can be identical or differently shaped. They also have end elliptical, in particular round, polygonal, or polygonal-like connections, via which they can be connected to the rotor 3 or at least indirectly to the drive. The length of each connecting piece 6 is selected such that one connection of the hollow shaft 4 is connected to a drive via the shaft connection 11. The opposite end connecting piece 6, which is connected to the rotor 3, can be shorter. The connecting pieces 6 are welded to the shaft tube 5 on both sides, and the weld seam is smoothed to create a smooth, seamless surface in which no dirt can accumulate and which is very easy to clean.

[0029] The above description thus describes a lightweight, easily disassembled container pump that can also be washed as a whole. REFERENCE MARK LIST

[0030] 1 Pump unit 2 Pump pipe 3 Rotor 4 Hollow shaft 5 Shaft tube 6 Connecting pieces 7 Pump base 8 Mechanical seal 9 Steel spring 10 Retaining element 11 Shaft connection 12 Stop

Claims

1. Pumping station for a container pump, preferably for use in the food industry, chemical industry and / or pharmaceutical industry, comprising a pump tube (2) in which a rotor shaft is received for connecting a rotor (3) connected to the rotor shaft to a drive unit, characterized by the fact that the rotor shaft is a tubular hollow shaft (4) made from a shaft tube (5) which is closed on both sides by end connecting pieces (6) made of a solid material.

2. Pumping station according to claim 1, characterized by the fact that the terminal connecting pieces (6) of the hollow shaft (4) are welded to the shaft tube (5) and the transitions are preferably smoothed.

3. Pumping station according to one of claims 1 or 2, characterized by the fact that the terminal connecting pieces (6) of the hollow shaft (4) and / or the shaft tube (5) are elliptical in cross-section, in particular round, or polygonal or polygonal in cross-section.

4. Pumping station according to one of the preceding claims, characterized by the fact that the terminal connecting pieces (6) of the hollow shaft (4) are identically shaped and the hollow shaft (4) is mirror-symmetrical.

5. Pumping station according to one of the preceding claims, characterized by the fact that the pumping unit (1), the pump pipe (2), the rotor (3) and the hollow shaft (4) are detachably connected to each other, in particular detachably without tools, preferably having threadless, manually detachable quick connections.

6. Pumping station according to one of the preceding claims, characterized by the fact that the hollow shaft (4) is rotatably mounted in a holding element (9) on the rotor side.

7. Pumping station according to claim 6, characterized by the fact that the retaining element (10) is a bearing which forms a cylinder that is flattened on at least one side and has a central through-opening for receiving the hollow shaft (4) and preferably adjacent media passages.

8. Pumping station according to one of claims 6 or 7, characterized by the fact that the retaining element (10) is mounted on the hollow shaft (4) in a rotationally free manner and a preferably welded or molded stop (12) is provided in the pump tube (2) which prevents further rotation of the retaining element (10) in the assembled state.

9. Pumping station according to one of the preceding claims, characterized by the fact that the hollow shaft (4), and / or the rotor (3) and / or a pump base (7) arranged at the end of the pump tube (2) are made of a chemically resistant, preferably inert, material, in particular stainless steel.

10. Pumping station according to claim 9, characterized by the fact that the pump tube (2) is fitted with seals made of a chemical-resistant material, preferably ethylene propylene diene rubber or fluorocarbon rubber.

11. Pumping station according to one of the preceding claims, characterized by the fact thatthe transition between pump tube (2) and hollow shaft (4) is sealed by means of a mechanical seal (8) and the mechanical seal (8) is held in position relative to the hollow shaft (4) in the pump tube (2) by means of a steel spring (9).

12. Pumping station according to one of the preceding claims, characterized by the fact that all contours within the pump tube (2) have smooth surfaces and smooth connection transitions.

13. Pumping station according to one of the preceding claims, characterized by the fact that either the pump pipe (2) or an outlet is assigned a flow meter for precise measurement of the volume flow.

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