Electric capacitor of variable capacitance

• US 4,450,500 A
• Filed: 05/26/1983
• Issued: 05/22/1984
• Est. Priority Date: 12/09/1982
• Status: Expired due to Fees

• Current Assignee: Draloric Electronic GmbH
• Original Assignee: Draloric Electronic GmbH
• Inventors: Wollenschlager, Werner
• Primary Examiner(s): Griffin, Donald A.
• Application Number:
  US06/498,244
• Time in Patent Office: 362 Days
• Field of Search: 361/277, 361/287, 361/327, 361/330
• US Class Current: 361/277
• CPC Class Codes: H01G 5/00 Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture

Abstract

An electric capacitor of variable capacitance, including a dielectric body comprised of densely sintered ceramic material, including a hollow space extending longitudinally through the tubular ceramic body for containing dielectric liquid. First and second dielectric liquids of different dielectric constants and densities are contained in the hollow space, and an adjusting cylinder connected to the hollow space adjusts the height levels of the two dielectric liquids in the hollow space for adjusting the capacitance of the capacitor. The hollow space is either longitudinal channels through the tubular body or is a radial space between two concentric tubular bodies which together define the dielectric body. The metal layers of the capacitor plates are respectively on the inside and the outside of the dielectric body.

Claims

1. An electric capacitor of variable capacitance, comprising:

a dielectric body comprised of densely sintered ceramic material;

the body having a hollow space extending through it for holding liquid dielectric therein;

the body having spaced apart surfaces generally at opposite sides of the hollow space;

capacitor plates in the form of metal layers on the spaced apart surfaces of the body, and the plates being separated by the hollow space for defining the capacitor plates;

the capacitor plates both having a respective height dimension;

a first liquid dielectric material of relatively higher dielectric constant present up to a variable height in the hollow space, and the variable height being in the electric field of the capacitor; and

a second liquid dielectric material of relatively lower dielectric constant and of lesser density than the first liquid located in the hollow space above the first liquid.

2. The capacitor of claim 1, wherein the plates are arranged a fixed distance apart.

3. The capacitor of claim 1, wherein the dielectric body is tubular in shape, and the spaced apart surfaces thereof are respectively radially inward and radially outward of the dielectric body.

4. The capacitor of claim 3, wherein the hollow space extends longitudinally through the body.

5. The capacitor of claim 4, wherein the hollow space comprises a plurality of longitudinal channels arrayed annularly around the tubular body.

6. The capacitor of claim 4, wherein the body is comprised of two tubular dielectric bodies, one inside the other, and the bodies are out of contact with each other, wherein the inner body has an outside diameter, and the outer body has an inside diameter, and the outside diameter of the inner body is less than the inside diameter of the outer body, for producing the hollow space between the inner and the outer bodies.

7. The capacitor of claim 6, wherein the tubular dielectric bodies are concentric.

8. The capacitor of claim 6, wherein the two tubular bodies are of the same dielectric constant.

9. The capacitor of claim 6, wherein the two tubular bodies are of different respective dielectric constants.

10. The capacitor of claim 6, further comprising anti-corona collars located at the longitudinal ends of and outside of the outer dielectric body.

11. The capacitor of claim 10, wherein the metal layer of one of the capacitor plates completely covers the inner surface of the inner tubular body, and the metal layer of the other capacitor plate completely covers the outer surface of the outer tubular body up to and not past the anti-corona collars thereof.

12. The capacitor of claim 6, further comprising a metallic clamp electrically in contact with the metal layer of the capacitor plate outside the outer tubular body.

13. The capacitor of claim 6, wherein the tubular bodies have opposite longitudinal ends;

metal plates at the opposite ends of the tubular bodies for closing off the longitudinal ends of the tubular bodies.

14. The capacitor of claim 13, further comprising a bolt extending longitudinally through the tubular bodies to the metal plates, and the metal plates being clamped to the bolt.

15. The capacitor of claim 13, further comprising pipe connections through the plates and into the hollow space for the first and second liquid dielectrics.

16. The capacitor of claim 15, further comprising nipples through at least one of the metal plates at the inside of the inner tubular body for the entry and the discharge of a cooling liquid inside the inner tubular body.

17. The capacitor of claim 15, wherein the metal plates seal off the hollow space and also seal off a space defined inside the inner tubular body.

18. The capacitor of claim 17, further comprising sealing rings at the metal plates for sealing off the hollow space and the space defined inside the inner tubular body.

19. The capacitor of claim 17, further comprising spring contact blades on at least one of the metal plates for contacting the metal layer of the capacitor plate on the inner body.

20. The capacitor of claim 6, wherein the tubular bodies have opposite longitudinal ends;

pipe connections into the hollow space for the first and second liquid dielectrics.

21. The capacitor of claim 20, further comprising an adjusting cylinder having a movable separating piston within the cylinder for defining separate chambers in the cylinder for the first and second liquid dielectrics, respectively, in the adjusting cylinder;

a respective pipe connected to the hollow space from each of the chambers of the adjusting cylinder, such that movement of the separating piston adjusts the height of the zone of separation of the first and second liquids in the hollow space.

22. The capacitor of claim 21, wherein the pipe for the first liquid is connected to the bottom portion of the hollow space and the pipe for the second liquid is connected to the top portion of the hollow space.

23. The capacitor of claim 21, further comprising the pipe for the second liquid having in it an expansion vessel which is located at the highest part of that pipe.