Ejector Tube of an Ejector Pump

Abstract

An ejector tube (5) of an ejector pump has an inlet area (4), a mixing area (7) and an outlet end (8) via which the medium to be delivered exits the ejector tube (5). A conduit section (10) adjoins the outlet end (8), the conduit section (10) is connected to the outlet end (8) of the ejector tube (5) so as to form a single piece.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application of International Application No. PCT/EP2006/066499 filed Sep. 19, 2006, which designates the Unites States of American, and claims priority to German application number 10 2005 046 449.1 filed Sep. 28, 2005 and German application number 10 2005 049 277.0 filed Oct. 14, 2005, the contents of which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The invention relates to an ejector tube of an injector pump with an inlet area, a mixing area and an outlet area via which the medium to be delivered exits the ejector tube. Ejector pumps are used for conveying fuel in fuel containers.

BACKGROUND

Such ejector tubes are components of ejector pumps in which they are inserted in axial alignment with respect to a propellant nozzle. A propellant supplied to the propellant nozzle via a propellant conduit exits the propellant nozzle under high pressure and enters the inlet area of the ejector tube. Because of the velocity of the propellant jet, a negative pressure is generated between propellant nozzle and ejector tube and is utilized to aspirate the medium to be delivered into the ejector tube. The propellant and the medium to be delivered exit the ejector pump via the outlet end. In order to transport the medium to be delivered to the desired location, the outlet end is connected to a conduit or conduit section. To connect the conduit section to the outlet end of the ejector tube, the conduit section is pushed onto the outlet end, the outlet end having on its external circumference a connecting geometry, preferably a Christmas-tree profile, in order to prevent unintentional detachment of the conduit section from the outlet end. A disadvantage is the assembly step for connecting the conduit section to the outlet end. Apart from the time required, relatively high assembly forces are necessary to ensure a secure fit of the conduit end on the outlet end without additional securing means, for example hose clips.

SUMMARY

An ejector tube of an ejector pump which makes possible simpler installation at low cost can be provided. According to an embodiment, an ejector tube of an ejector pump may comprise an inlet area, a mixing area and an outlet end via which the medium to be delivered exits the ejector tube, and a conduit section adjoining the outlet end, wherein the conduit section is connected to the outlet end of the ejector tube so as to form a single piece.

According to a further embodiment, the conduit section may be a corrugated tube. According to a further embodiment, the conduit section can be a smooth tube. According to a further embodiment, the outlet end and the conduit section may be made of the same material, preferably POM or PA. According to a further embodiment, the outlet end and the conduit section may be made of different materials. According to a further embodiment, the outlet end may have an internal contour configured as a diffuser. According to a further embodiment, the diffuser may merge continuously into the internal diameter of the conduit section.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail with reference to a number of exemplary embodiments. In the drawings:

FIG. 1 is a schematic representation of an ejector pump according to the prior art in cross section;

FIG. 2 is a schematic representation of an ejector pump according to an embodiment in cross section, and

FIG. 3 shows the ejector tube according to FIG. 2 in a further embodiment.

DETAILED DESCRIPTION

According to various embodiments, a conduit section adjoins the outlet end and in that the conduit section is connected to the outlet end of the ejector tube so as to form a single piece.

With the one-piece configuration of the outlet end of the ejector tube and a conduit section, subsequent assembly of the conduits to the ejector tube of an ejector pump is dispensed with. Because of the one-piece configuration, connection geometries are not required on the outlet end of the ejector tube and on the conduit section. Manufacturing costs are thereby considerably reduced because, firstly, the consumption of material is reduced and, secondly, the injection molding tools are not required if the ejector tube geometry is contained in the tool for the conduit section.

According to a further embodiment, the conduit section is in the form of a corrugated tube. This is advantageous, in particular, if the conduit adjoining the ejector pump must be installed with small bending radii.

In another configuration, a good transition between the outlet end of the ejector tube and the adjoining conduits is achieved with a conduit section configured as a smooth tube.

Manufacture of the ejector tube and the conduit section is especially inexpensive if the outlet end and the conduit section are made of the same material, for example polyoxymethylene (POM) or polyamide (PA).

Depending on the demands placed on the conduit adjoining the ejector pump, it may be advantageous if the outlet end of the ejector tube and the conduit section are made of different materials. An ejector tube configured in this way with a conduit section can be produced with low cost and complexity using the two-component injection molding method.

According to a further embodiment, the outlet end has an internal contour configured as a diffuser.

According to a further embodiment, turbulence at the end of the ejector tube can be avoided in that the diffuser merges continuously into the internal diameter of the conduit section.

The ejector pump according to the prior art represented in FIG. 1 has a housing 1 in which a propellant nozzle 2 is arranged. The propellant nozzle 2 is supplied with fuel as propellant via a connection 3, so that the propellant jet is injected from the propellant nozzle 2 into the mixing tube 5 via an inlet area. The inlet area 4 is followed in the flow direction by a confuser 6, which, however, is not essential. It is followed by a mixing area 7 of constant cross section which is followed by a diffuser 8 in the region of the outlet end. A Christmas-tree profile 9, on which a conduit section 10 is fitted, is formed integrally on the circumference of the outlet end 8 of the mixing tube 5. The total jet emitted by the ejector pump is conducted away via the conduit 10. The total jet is composed of the propellant jet and the conveyed fuel, the conveyed fuel being aspirated via the suction area 11 as a result of the negative pressure generated in the region of the inlet area 4 by the propellant jet.

FIG. 2 shows an ejector pump according to an embodiment with the basic structure according to FIG. 1. However, it differs at the outlet end 8 of the mixing tube 5, which does not have a Christmas-tree profile. The outlet end 8 merges without transition into a conduit section 10 for conducting the total jet onwards. The conduit section 10 is configured as a smooth tube. Both the ejector tube 5 and the conduit section 10 are made of PA and are produced by injection molding. The ejector tube 5 shown in FIG. 3 differs from the ejector tube 5 according to FIG. 2 only in that the conduit section 10 is configured as a corrugated tube.

Claims

1. An ejector tube of an ejector pump comprising an inlet area, a mixing area and an outlet end via which the medium to be delivered exits the ejector tube, and a conduit section adjoining the outlet end, wherein the conduit section is connected to the outlet end of the ejector tube so as to form a single piece.

2. The ejector tube according to claim 1, wherein the conduit section is a corrugated tube.

3. The ejector tube according to claim 1, wherein the conduit section is a smooth tube.

4. The ejector tube according to claim 1, wherein the outlet end and the conduit section are made of the same material.

5. The ejector tube according to claim 1, wherein the outlet end and the conduit section are made of different materials.

6. The ejector tube according to claim 1, wherein the outlet end has an internal contour configured as a diffuser.

7. The ejector tube according to claim 1, wherein the diffuser merges continuously into the internal diameter of the conduit section.

8. The ejector tube according to claim 1, wherein the outlet end and the conduit section are made of the same material, wherein the material is polyoxymethylene (POM) or polyamide (PA).

9. A method of manufacturing an ejector tube of an ejector pump comprising the steps of:

providing an inlet area, a mixing area and an outlet end via which the medium to be delivered exits the ejector tube, and

adjoining a conduit section to the outlet end, wherein the conduit section is connected to the outlet end of the ejector tube so as to form a single piece.

10. The method according to claim 9, wherein the conduit section is a corrugated tube.

11. The method according to claim 9, wherein the conduit section is a smooth tube.

12. The method according to claim 9, wherein the outlet end and the conduit section are made of the same material.

13. The method according to claim 9, wherein the outlet end and the conduit section are made of different materials.

14. The method according to claim 9, wherein the outlet end has an internal contour configured as a diffuser.

15. The method according to claim 9, wherein the diffuser merges continuously into the internal diameter of the conduit section.

16. The method according to claim 9, wherein the outlet end and the conduit section are made of the same material, wherein the material is polyoxymethylene (POM) or polyamide (PA).