Getter sorption pump with heat accumulator for high-vacuum and gas discharge systems

A getter sorption pump has at least one getter member of non-evaporation getter material and a corresponding heating element. With this getter pump, a high pump rate is achieved by means of an extremely large surface in the smallest possible space. For this purpose, the heating element is disposed in an insulating tube and a plurality of individual getter members are attached to the insulator tube at a spacing from one another. The getter pump is employed in high-vacuum and gas discharge systems.

BACKGROUND OF THE INVENTION 
The invention relates to a getter sorption pump for high-vacuum and gas 
discharge systems comprising at least one getter member of non-evaporating 
getter material and a corresponding heating element. 
In order to achieve a high pump power, a plurality of individual getters 
had to be previously interconnected, whereby the efficiency increasingly 
deteriorated with respect to the heating capacity, the problem of heat 
dissipation intensified, and the space requirement for the accommodation 
of the individual getters increased, which caused problems. Heating 
capacity had to be constantly supplied in order to stabilize the pump 
power over a longer time. 
Since the traditional getter substances only develop their optimum pump 
capabilities for various gases at specific temperatures (selective pump 
properties), the working temperature either had to be varied or the 
individual getters had to be held at different temperatures with at least 
two heating elements. 
These necessary techniques were usually disregarded in practice so that the 
optimum getter properties of the non-evaporating getters remained 
unexploited. Even previously disclosed getter pumps which comprise a 
larger, compact getter member instead of many individual getters exhibit 
the most significant of these disadvantages. 
SUMMARY OF THE INVENTION 
An object of the invention is to increase the specific performance of 
getter pumps given simultaneous reduction of the necessary heating 
capacity and to stabilize them with the assistance of a heat accumulator 
having extremely high heat storage capacity. It is also an object to 
achieve a high pump rate by means of an extremely large surface in the 
smallest possible space. 
This object is achieved by providing the heating element within an interior 
of the insulating tube and externally attaching a plurality of individual 
getter members to the insulating tube and spaced from one another. 
The pump rate of a getter member increases with its surface, and with its 
porosity as well; but capacity, on the other hand, increases with its 
mass. Together, both factors define the time-wise stability via the 
quantity of gas absorbed. This stability is also influenced by the working 
temperature, which is dependent on the type of gas. 
The reduction of the necessary heating capacity in comparison to the 
employment of many individual getters results from the more efficient use 
of the heating capacity from the heating element, for example a heating 
coil (lower radiation losses). 
The heat accumulation is achieved by means of the ceramic compound 
integrated into the structure. The possibilities are extraordinarily 
flexible and can be easily optimized. 
A further advantage of the energy-saving heat accumulation is that a 
heat-conditioned, good pump effect is maintained over a longer time after 
the heating voltage has been shut off. Such a shut-off is, for example, 
absolutely necessary in nuclear accelerator systems in order to avoid 
disruptions due to foreign fields. 
The slow cooling of the getter member also has an advantageous effect since 
the temperature-dependent, selective optimum pump ranges are very slowly 
crossed, and thus all important absorption maximums dependent on the type 
of gas are covered. 
The invention shall be explained in greater detail with reference to 
exemplary embodiments. Parts that do not necessarily contribute to an 
understanding of the invention are unreferenced or have been omitted from 
the drawing. Mutually corresponding parts in the figures have been 
provided with the same reference characters.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The getter sorption pump shown in FIG. 1 is comprised of the heating 
element 1 which is disposed in an insulating tube 2 preferably consisting 
of ceramic. The plurality of individual ring-shaped getter members 3 
surround and are attached at a spacing from one another on the insulating 
tube 2. This arrangement is surrounded by a pump vessel 7 which can be 
connected to the high-vacuum system with a pump flange 8. The heater leads 
9 are conducted through the pump vessel 7. 
FIG. 2 again shows the insulating tube 2 which is equipped with the heating 
element 1. It preferably consists of ceramic and serves as a heat 
accumulator. In this exemplary embodiment, the individual getter members 3 
are applied to metal wafers 5 of molybdenum or tungsten. The metal wafers 
5 are provided with spacing beads 6. The metal wafers 5 can also be 
designed as pipe socket parts. Both a good thermally conductive connection 
to the insulating tube 2 as well as the desired spacing of the individual 
metal wafers thus result. 
FIG. 3 shows a getter sorption pump wherein the individual getter members 3 
applied to the insulating tube 2 of ceramic in which the heating element 1 
is provided are spaced from one another by means of metal or ceramic rings 
4. 
The FIG. 2 and FIG. 3 structures will now be discussed in greater detail. 
The metal discs 5 illustrated in FIG. 2 consist of molybdenum or tungsten 
sheet metal. The getter members 3 are sintered onto the metal discs and 
consist, for example, of mixtures of zirconium carbon (graphite) or 
zirconium graphite with added ammonium salts (e.g. ammonium carbonate). 
The getter members 3 can have a variety of shapes. For example, they can 
be circular or square. Preferably, the discs 5 can have a flange ring-type 
design like a pipe socket part. 
The metal discs 5 surround the insulating pipe 2 in FIGS. 2 and 3. The 
arrangement in both embodiments is rotationally symmetrical. The heating 
elements in all Figures are mounted outside the insulating pipe with 
straps or clips. Gaps are required between the getter members. This is 
achieved either through spacing beads (FIG. 2) or by spacing rings 4 (FIG. 
3). The metal discs 5 in FIG. 2 illustrated in lateral view, have recesses 
(beads 6), with a strip-shaped extension, and are provided with the 
individual getter members 3. 
In all of the above embodiments, the individual getter members 3 consists 
or are comprised of zirconium, titanium, thorium, tantalum, platinum, 
niobium, cerium, palladium, and mixtures or alloys thereof. 
Although various minor changes and modifications might be proposed by those 
skilled in the art, it will be understood that I wish to include within 
the claims of the patent warranted hereon all such changes and 
modifications as reasonably come within my contribution to the art.