DE2327362A1 - Expanding bellows temp. compensator for HF resonant cavities - has bimetal adjustable bellows moving conducting membrane in cavity wall - Google Patents

Abstract

The temp. compensator has a radially corrugated, circular, conducting membrane covering a hollow in the cavity wall. The centre of the membrane is attached to a post which passes through the cavity wall to the outside. The expanding bellows, which drive the membrane in and out, thus altering the resonant frequency of the cavity are located around the post between the rear of the membrane and the outer wall of the hollow. The bellows consist of a number of bimetal strips bent out into V-shapes and connected so that their motions induced by temp. change add. The position of the membrane may be set manually by a knob fastened to the outer end of the post.

Description

PATENTANWÄLTE 8 MÜNCHEN 2, 28, H SS 1973

mm iMM Λΐ in-r- \ a / ai ι λ j "» i_i KAUFINQERSTRASSE 8

DIPL-INQ-CURTWALLACH phone 240275

DIPL-ING. GÜNTHER KOCH 2327362

DR. TINO HAIBACH our reference: U 235 -K / vM

Spinner GmbH Electrotechnical Factory, 8 Munich 2,

Erzgießereistr. 33.

Arrangement for temperature compensation of HF cavity resonators

The invention relates to an arrangement for temperature compensation of RF cavity resonators.

It is known that resonator circuits, especially when using high power are applied and have a high quality, change their resonance frequency with the temperature. It is therefore required to make a temperature compensation. In the case of conical circles, such temperature compensation is relative simply possible because the inner conductor can be made of a material with a coefficient of thermal expansion is negligibly small or internally you switch materials of different dimensions one after the other, which results in each other results in a relatively cheap temperature compensation.

However, difficulties arise with the temperature compensation of cavity resonators, which must have considerable dimensions at the low frequencies of the television sector, the are made of cast or welded construction. In these cases a design is made of a non-stretching material inexpedient for price reasons and for reasons of technology, if not impossible.

The invention is therefore based on the object of a ^! To create a temperature-compensated cavity resonator that reduces the resonance

409881/0459 ^{# /} *

frequency regardless of its temperature, even with rapid temperature changes keeps constant on the set wave value.

According to the invention, this object is achieved in that a cutout is provided in a wall of the resonator, the is closed with a membrane which, depending on the temperature, can be displaced perpendicular to the resonator wall in the sense of a change in volume is. By changing the volume, the resonance frequency is influenced in the sense of keeping it constant. In the field-free space on the back of the membrane are to adjust the Volume temperature-dependent members, preferably used in the form of bimetal disks, the preload of which by spring force can be adjusted and the preload can be adjusted using a scale. This allows the steepness of the compensation characteristic, i.e. adjust the change in deflection of the membrane over a wide range depending on the temperature. This is advantageous because the different resonance frequencies to which the resonance circuit is adjustable, bring different heating conditions in the resonance circuit and therefore a different one Require adjustment.

An exemplary embodiment of the invention is described below with reference to the drawing. The only figure in the drawing shows a sectional view of a cavity resonator wall with inserted compensation membrane, with the upper half above the center line shows the installation in a housing wall of the resonator, while the lower half shows an installation, e.g. on a tuning slide.

In a section of the resonator wall or a tuning slide a corrugated membrane 10 is used, which is connected at the edge via a soldered seam 12 to the housing. With permanent installation in a housing 14 (upper half of the drawing) it is useful to

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an intermediate piece; 16 to be inserted into a housing opening and to be secured with screws 18 distributed over the circumference. Through this assembly is made easier. When retrofitting, e.g. on a tuning slide, the housing 20, which is attached to the tuning slide 24 with screws 22, a worm contact 26 known per se, which ensures proper contacting of the housing 20 on the slide 24.

On the inside, the membrane only bears over the middle section the membrane extending plate 28, through the center hole

screwed or riveted a threaded bolt 30 and riveted to its head ^ is. This screw bolt 30 protrudes through a hole in the housing wall to the outside. On the protruding part of the bolt 30 a sleeve 32 with disc springs 34 is placed on the one hand at the base of the sleeve 32 and on the other hand on an adjusting ring 36, which is screwed onto the thread of the bolt 30. The free end of the sleeve 32 stands in an annular groove of the adjusting ring 36 a. The adjusting ring 36 is encompassed by a knurled sleeve 38 which carries a scale on the conically tapered portion 40, which can be read off against a scale on the outer circumference of a ring 42 is screwed onto the thread of the bolt 30. and is fixed in a rotationally fixed manner by means of a screw 44. By rotating the adjusting ring 36 or the one surrounding it in a rotationally fixed manner, with external knurling provided handle ring 38 can bias the Disc springs 34 can be changed.

Between the plate 28 resting against the membrane 10 and the housing wall 16 and 24 are compensation disc springs 46 supported, the preferably made of bimetal and so sized and arranged are that when the temperature changes, the volume of the space 48 between the membrane and the wall in the sense of keeping the constant Resonance frequency is changed.

409881/0459

Instead of the compensation springs 46 could be a temperature-dependent Also link a liquid filling in the space 48 be provided, the liquid must have a corresponding coefficient of expansion. The one with the Temperature-controlling liquid-filled bodies at the same time represent the tuning parameters of the cavity resonator.

The wall of the resonator can expediently be made very thin in order to achieve a short thermal time constant.

According to a further embodiment of the invention, the tuning slide itself can be made of bimetal and itself bend in such a way that the space is changed in the sense of keeping the resonance frequency constant.

In all cases, the thermal inertia, i.e. the heat transfer rate, to the elements sensitive to temperature designed in such a way that a quick response to fluctuations in performance is possible.

Claims

09881/0459

Claims (1)

Patent claims: (l.) Arrangement for temperature compensation of RF cavity resonators, characterized in that a cutout is provided in a wall (14,24) of the resonator, which is closed with a membrane "(10), the temperature-dependent perpendicular to the rear wall in the sense of a Volume change is displaceable. 2. Arrangement according to claim 1,. characterized in that in the field-free space on the back of the membrane (28) temperature-dependent members (46) are arranged. J). Arrangement according to Claim 2, characterized in that a peder element (46) is tensioned relative to one another as a function of temperature and a spring element (54) is not tensioned as a function of temperature and fix the mechanical position of the membrane (10). 4. Arrangement according to claim J5, characterized in that the temperature-dependent spring element consists of plate-shaped Consists of bimetal discs (46). 5. Arrangement according to claim J>, characterized, that the preload of the temperature-dependent spring links () is variable. 6. Arrangement according to claims J> to 3 » characterized in that the spring washers (46 or 34) on a threaded bolt fastened with its head on the membrane (10) within the. 409881/0459 Cavity (48) or outside the wall (16) are placed and that the disc springs (34) by an adjusting ring (36,38) are preload. 7 ". Arrangement according to claim 6, characterized in that that with a scale on the circumference of the collar a scale cooperates on the circumference of a ring (42) fixed on the bolt. 8. Arrangement according to one of claims 1 to 7, characterized in that that the membrane is circular and corrugated in the range of motion. 9. Arrangement according to claim 8, characterized in that the membrane (10) through a soldered seam (12) in the cavity resonator is fixed. 10. Arrangement according to one of claims 1 to 9, characterized in that that the membrane (10) is housed in a separate housing (20) which is inserted into the resonance circuit. 11. Arrangement according to claim 10, characterized in that the housing (20) carrying the membrane is on a tuning slide (24) is attached. 12. Arrangement according to claim 11, characterized gekennzei chnet that the membrane (10) supporting the housing (20) via a Worm contact (26) is in contact with the tuning slide (24). 409881/0459 Γ5 · arrangement according to one of claims 1 to 12,. ' thereby g e k e η η ζ e i c h η e t, "that with the tuning slide the thermal inertia, i.e. the heat transfer rate to the temperature-dependent elements is designed favorably in order to react quickly to fluctuations in output to enable. Ik. Arrangement according to Claims 1 to 1, characterized in that the membrane (10) itself is made of bimetal and, in the sense of a change in volume, bulges in the shape of a sphere when the temperature changes. 15. Arrangement according to claim 1, characterized, that the tuning slide is made of bimetal and look in terms of a volume change with temperature fluctuations arched through. 16. Arrangement according to claims 1 to 15, characterized in that that when using temperature door-dependent tuning slide plates a mechanical counterforce by a bath the tuning characteristics influenced. 17. Arrangement according to claim 16, thus g e k e η η ζ ei without t, that the spring force can be preset. 18. Arrangement according to ^ inem of claims 1 to 17 » characterized, that the compensation is on one of the rigid walls of the resonator is appropriate. • A 40 988 1/04 59 19 · Arrangement according to claims 1 to 17. » characterized in that a wall of the resonator consists of a material which deflects when the temperature changes in the sense of a change in the cavity. 20. Arrangement according to claim 19, characterized in that the wall consisting of the temperature-dependent material of the resonator is made thin in order to achieve a short thermal time constant. 21. Arrangement according to claim 19 * • characterized in that the wall consisting of temperature-dependent material is mechanically covered and protected by a second wall so that the spring is supported against tension against this protective wall. 22. Arrangement according to claim 1, characterized in that the temperature-dependent element is a liquid filling is provided. 23. Arrangement according to claim 22, characterized in that the temperature-controlling liquid is filled Body at the same time represents the tuning membrane of the cavity resonator. 4U9881 / 0459