Potential equalization for a metering pump

Abstract

Metering pump having a stationary portion and a pump portion, which is mounted in a linear manner and can be moved relative to the stationary portion in order to move a displacement body, wherein, for the purpose of achieving a long service life, the pump portion is connected in an electrically potential-equalizing manner to the stationary portion via an electrically conductive spring element.

Claims

1. A metering pump having a stationary portion and a pump portion, which is mounted in a linear manner and can be moved relative to the stationary portion in order to move a displacement body, wherein the pump portion is connected in an electrically potential-equalizing manner to the stationary portion via an electrically conductive spring element.

2. The metering pump according to claim 1, wherein the pump portion is designed to move in a purely translational manner.

3. The metering according to claim 1, wherein the metering pump has a pump drive, which is in the form of a linear drive.

4. The metering according to claim 1, wherein one end of the spring element is in electrically conductive contact with the stationary portion, and one end of the spring element is in electrically conductive contact with the pump portion.

5. The metering pump according to claim 1, wherein the spring element is in the form of a helical spring.

6. The metering pump according to claim 4, wherein the spring element, in particular the helical spring, is arranged around at least part of the pump portion.

7. The metering pump according to claim 1, wherein the spring element, in particular the helical spring, is arranged in such a manner that its spring force assists the pumping force required for pumping by virtue of the spring force acting at least partly in the direction of the pumping force.

8. The metering according to claim 2, wherein the metering pump has a pump drive, which is in the form of a linear drive.

9. The metering according to claim 2, wherein one end of the spring element is in electrically conductive contact with the stationary portion, and one end of the spring element is in electrically conductive contact with the pump portion.

10. The metering according to claim 3, wherein one end of the spring element is in electrically conductive contact with the stationary portion, and one end of the spring element is in electrically conductive contact with the pump portion.

11. The metering pump according to claim 2, wherein the spring element is in the form of a helical spring.

12. The metering pump according to claim 3, wherein the spring element is in the form of a helical spring.

13. The metering pump according to claim 4, wherein the spring element is in the form of a helical spring.

14. The metering pump according to claim 5, wherein the spring element, in particular the helical spring, is arranged around at least part of the pump portion.

15. The metering pump according to claim 2, wherein the spring element, in particular the helical spring, is arranged in such a manner that its spring force assists the pumping force required for pumping by virtue of the spring force acting at least partly in the direction of the pumping force.

16. The metering pump according to claim 3, wherein the spring element, in particular the helical spring, is arranged in such a manner that its spring force assists the pumping force required for pumping by virtue of the spring force acting at least partly in the direction of the pumping force.

17. The metering pump according to claim 4, wherein the spring element, in particular the helical spring, is arranged in such a manner that its spring force assists the pumping force required for pumping by virtue of the spring force acting at least partly in the direction of the pumping force.

18. The metering pump according to claim 5, wherein the spring element, in particular the helical spring, is arranged in such a manner that its spring force assists the pumping force required for pumping by virtue of the spring force acting at least partly in the direction of the pumping force.

19. The metering pump according to claim 6, wherein the spring element, in particular the helical spring, is arranged in such a manner that its spring force assists the pumping force required for pumping by virtue of the spring force acting at least partly in the direction of the pumping force.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Preferred embodiments of the invention are shown by way of example in the figures, in which:

[0018] FIG. 1 shows a cross section through a first embodiment of the invention, and

[0019] FIG. 2 shows a cross section through a first embodiment of the invention.

DETAILED DESCRIPTION

[0020] FIG. 1 shows a first embodiment of the invention in cross section.

[0021] The metering pump 1 comprises a pump head 2, which is inserted into a housing 62 of the metering pump 1. The pump head 2 comprises a displacement body 23. The displacement body 23 is part of a pump portion 3. The pump portion 3 also comprises a drive rod 43. The latter can be driven by an electromagnetic linear drive 4 and moves in a linear manner during operation. The linear drive 4 also comprises a stator 46, which is connected to the housing 62. In the present embodiment, a rotor of the linear drive 4 is formed by the drive rod 43. The stator 46 is connected to the housing 62 of the metering pump. The linear drive 4 can be electrically connected via an electrical connector 45. The pump head 2, the stator 46 and the housing 62 form at least part of a stationary portion 6 of the metering pump 1, which can be moved relative to the pumping portion 3.

[0022] The metering pump 1 also comprises a spring element 7, which is in the form of a helical spring in the present embodiment. The spring element 7 is arranged between the housing 62 and the drive rod 43. This arrangement produces an electrical connection between the stationary portion 6 and the pump portion 3, as a result of which potential equalization and suitability for explosion-protected areas can be achieved. The drive rod 43 and the housing 62 are designed to be electrically conductive at least at the point of contact with the spring element 7. For example, the drive rod 43 and the housing 62 can be or comprise metal components.

[0023] FIG. 2 is for the most part identical to FIG. 1, wherein the same features are designated by the same reference signs. No specific description of these features is given. Reference should be made to the description of FIG. 1.

[0024] One difference from FIG. 1 is the arrangement of the spring element 7. In FIG. 2, the spring element 7 is arranged between a supporting device 47, which is fastened to the drive rod 43 and is in the form of a disk in FIG. 2, and the stator 46 of the linear drive 4. The supporting device 47 is preferably designed to be electrically conductive, for example is made of metal.

[0025] Both in the illustration of FIG. 1 and in FIG. 2, the drive rod 43 moves downward when the metering pump 1 generates pressure. In both of the embodiments shown, this movement is assisted by the spring element 7, which relaxes during this movement. This reduces the force generation requirements placed on the linear drive 4.