DE1252353B - Process for removing impulsive gases break in a recipient - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

F04b

German KL: 27 d- 4/00

Number: 1252 353

File number: U 7504 VIII c / 27 d

Filing date: October 10, 1960

Opened on: October 19, 1967

The invention relates to a method for removing sudden gas penetrations into a recipient, in which an equilibrium pressure of less than 10 ~ ^e mm Hg "is continuously established by means of a vacuum pump.

The term "getter metal" is understood to mean metals which generally contain large amounts of adsorb most of the gases that are present together in vacuum equipment. If not explicitly otherwise mentioned, this term is related to a getter metal that is at least partially degassed or was baked out. Particularly preferred getter metals used in the method according to the invention are mentioned below.

In the current technology of mass spectroscopy, the particle accelerators of thermonuclear reactions, electronics, space exploration and similar fields, the threshold values of the pressures are often much lower than 10 ~ ^e mm Hg or pure samples, and the thresholds of nuclear reactions can be due to pressures of 10 ~ ¹⁰ mm Hg or less.

In modern technology, maximum requirements are placed on vacuum pumps, for example in plasma tests, accelerator systems and phone sources, in which vacuum conditions must be maintained in which almost every gas particle is removed. High-energy charged and neutral particles are continuously introduced into these devices or generated in the system. The vacuum pump must be able to perform both the initial evacuation and the subsequent removal of all the required fast particles and a portion of slow neutrals in order to obtain a very low density of the "cold" neutral gas. Under optimal conditions, the fast particles should be removed without prior conversion to slow particles, which is not possible with diffusion pumps, since fast particles can be difficult to enter the nozzles of a diffusion pump. Further, if fast particles are reduced to slow ones first, a wider entrance mouthpiece must be provided since fast particles can be shot through a narrow opening, while slow particles cannot. A method and apparatus for creating vacuums as high as 10 ~ ¹⁰ mm Hg and below and pumping out the corresponding thousands of liters of method for removing jerky
Gas ingress into a recipient

Applicant:

United States Atomic Energy Commission,

Germantown, Md. (V. St. A.)

Representative:

Dr.-Ing. W. Abitz, patent attorney,

Munich 27, Pienzenauer Str. 28

Named as inventor: '

Norman Milleron, Berkeley, Calif. (V. St. A.)

Claimed priority:
V. St. v. America October 16, 1959
(847 033) ^:

as can be sustained per second in the use of getter pumps or ion getter pumps, in which the recipient and / or the collecting electrodes continuously with degassed or Purified getter metal are coated by a source of getter metal that is contained within the recipient is arranged in the vicinity of the collecting electrodes, is evaporated. The gases that go into these recipients enter and which impinge on the walls or on the collecting electrodes of the same are absorbed and from the fresh layer of desorbed getter metal continuously deposited thereon is covered.

In such a pumping device, a wire or strip of suitable getter material becomes continuous introduced into a pump room or a recipient through an externally cooled supply pipe, which is suitable for thermally shielding the wire or strip, and which is made of one material is made, the coefficient of thermal conductivity is large enough to contain or generated in the pipe surface Remove heat. When exiting the tip of the cooled tube into the recipient, the wire exposed to bombardment by an electron beam or other heating devices that cause that the wire, which is located outside the feed tip, is heated and melted. The exiting Tip is preferably in a vertical one

709 678 / G1

3 4

Positioned to ensure a symmetrical distribution of expensive coatings on the inner surfaces of the recipients of the metal formed by the force of gravity during this period, and further the wire is generally reduced when the number of gas particles actually trapped is too high the level of the electron generator or which can be relatively small.
Heat source arranged to ensure a slight melting 5 There is also already known a pump (USA.-mainly in the outermost tip of the wire to patent specification 2,894,679), in which in a reciprocating effect. The molten metal tends to form a layer of getter metal deposited into a molten sphere which is in communication through the top of a high vacuum pump. In the known arrangement, the output of the high-heating devices is suitably controlled by the pump cooling, the wire feed device and the output of the gettering layer. vacuum pump increased, whereby the getter acts practically as the term "melted main pump, if at a pressure below ball" the cohesion of any mass of 10 ~ 'mm Hg is evacuated,
Understood molten metal on the wire tip, the method according to the invention is not that caused by surface tension. The objective is to expand the pumping capacity into areas of heat in the wire behind the molten ball of higher vacuum, but the objective is diverted to the feed tube mainly by radiation rather than conduction using a getter or ion. The getters, even in the case of sudden gas ^{penetrations, uniformly melted metal in the ball is radiated outwards at weight pressures of less than 10 ~ e} mm Hg in an upright "line of sight", while at the same time maintaining further metal from the wire fed in without continuous vapor deposition fresh getter material is melted onto the recipient in order to flatten the melted mass again.

to complete. The getter metal wire is natural. The method according to the invention is thereby

degassed before introduction into the recipient and indicates that such a getter

Narrow tolerances are deposited between the feed 35 metal layer that the gases at

wire and the feed pipe adhered to. absorbs these small pressures much faster

When working with a simple getter pump as desorbed, the absorption capacity of the

the gas absorption on the continuously getter metal layer is higher than the number of

vapor-deposited metal coating used to protect a particle in the event of such a sudden gas ingress,

create high vacuum after usually the 30 so that initially by absorbing these particles

The equilibrium pressure is initially withdrawn to a pressure of about ΙΟ " ⁴ mm on the getter metal layer

Hg was evacuated with a foreline pump, d. H. which is sustained, and that after absorption

Particles that remain in the recipient return more slowly from the getter metal layer

randomly collide with the walls of this recipient, gases then desorbed from the vacuum pump,

which is connected to the container to be evacuated, 35 the connection of which is in the vicinity of the getter metal

and will be stuck on the walls as a result of the layer being removed,

continuously growing coating of adsor- The use of the getter effect is for rapid

bicrcndcm metal. Degassing of tubes known (»GetterstofFe« from

When applying the getter principle for ions, Martin Littmann, Leipzig, 1938, p. 44), where the

Getters can pump gaseous particles that enter 40 getters shortly before or after melting

are to be removed, is arbitrarily evaporated into an area between electron tubes,

two cathode plates enter. However, a stream of these getter substances are primarily one

Electrons that pass between the cathode plates - reactants and not an absorption desorp-

running or other devices ionize the gassing means, as is the case with the method according to the invention

molecules, and the resulting clays are 45 needed. As a result, the material does not work

attracted by the cathode plates. More common- as a buffer. These getters form an integral part

wisely, the ions can remove the plates after contacting the tube, in order to extend its service life, and

leave them again, as they are not a part of the pump

have loren and have become neutral molecules. Manufacturing process for electron tubes will not

As a result of the arrangement of the getter metal evaporation 50 gas is removed from an enclosed space, but

source, which has been described above, held within the on its walls. When inventing

On the other hand, a sudden over-

platlcn, however, the getter material vapor hits pressure or occurs at a certain point

these plates, and the cathode bundles of particles in the vicinity of the pump

Plate-attracted ions are thus temporarily absorbed by the getter substances after 55 and later

Neutralization adsorbed or removed from it continuously by the diffusion pump,

covered metal. An application example for the invention

When using the device methods described above, devices for containment

tion in combination with getter metals such. B. of plasmas for attempts to achieve controlled

Titanium, tantalum, tungsten, molybdenum, zirconium, niobium, 60 nuclear fusion processes. This is where the plasma becomes

Rhenium, thorium and uranium, the negligible confining magnetic field of neutral particles

Having vapor pressures can traverse vacuums with pressures of high energy. Some of these particles

of 10 ~ ^J0 mmHg and smaller are ionized upon collision with the plasma

while pumping speeds are reached that and captured. The non-ionized particles occur

Hundreds of thousands of liters per second. 65 on the other side of the magnetic field.

In many cases, as described below, no device was previously known which in

will be, a very high vacuum for a long time is able to remove these particles before they can

be maintained. So far they were very back in the magnetic field as slow particles

5 6

enter, which most of their energy through a well-known ion pump (German design

Collisions with walls and the like. Lost writing 1 065 561) a getter metal is also used.

to have. A slow particle and a high-energy det that has the purpose of breaking the vacuum in a

Plasma ions exchange their charge when they collide, and after this has been sealed in a vacuum-tight manner

the newly formed neutral particle results in the largest 5 is to maintain for a long time. A throttle,

Part of the energy with yourself. This loss of energy is introduced into this closed recipient

deprives the plasma which would lead to a fusion, but would inevitably increase the

necessary energy. The invention is not concerned with resulting in pressure, since there is no constant evacuation

generally an ^{equilibrium pressure of about 10} mm is carried out by a vacuum pump, and the

Maintain Hg. Since the undesirable conditions under which the absorption-desorption

th particles caused total pressure increase to equilibrium in the manner according to the invention

is relatively small, for example diffusion interception of a gas surge can be used

pumps are quite capable of equilibrium, which are not disclosed in this interpretative document,

to maintain pressure or to quickly restore it

place. Rather, the main difficulty lies in the fact that the absorption-desorption

in eliminating these slow particles before equilibrium of the getter metal layer in the invention

they cross the magnetic field again, d. H. proper way only at pressures below

so: immediately. 10 ~ ^e mm Hg can be harnessed.

Finally, another arrangement is known for solving the problem on which the invention is based

Task is sufficient to know the total pumping ao (German Auslegeschrift 1 046 249), in which a

speed P of a getter metal alone is not enough. Adsorption and desorption of gas ions on one

The absorption rate A and the movable getter metal layer must be determined locally in

Know the desorption speed D , which is that of a chamber communicating with a pump

Pump speed is heated according to the following equation and thereby degassed. This arrangement

determine: as is their structure as a result of the intended rotation

dA aD tion movement of the carrier layer and the required

P - ~ fa jj ~ ·. Heating device not only significantly more complicated than

the implementation of the inventive

The inventor therefore uses a getter metal, when driving the device, but it works

^ which not only with respect to M, _son countries also ³ ° 3 ^ ™ ^ '^' ^{BEWE "un} S ^{of the} getter

is small in the absolute sense and in which the die used in the method according to the invention Absorption probabilities in a composite getter substance are known per se, for example collision of a gas particle with the getter metal is large. Tantalum, tungsten, zirconium and molybdenum from »High In the device according to the above-mentioned USA.- 35 Vakua "by S. Inanananda, 1947, p. 293. Patent Specification 2,894,679 is continuously getter When carrying out the metal vapor according to the invention down to the absorbed driving becomes a vacuum pump recipient, the one To cover gases and the old getter metal low getter metal surface with pumping effect, strike to renew. Already from this process only goes either coated with fresh metal or show that it is surprising that the getter metal 40 degassed, and the recipient and / or the neighboring one layer for suddenly trapping a blast of gas vacuum chamber is raised to a pressure of about to be able to use, because for this purpose 10 ~ ° mm Hg or below must be evacuated. To this

■. ",. dfl ". ...,. -τ- * L point in time, if not earlier, a diffusion

yes, the value - ^ be extraordinarily acceptable. Hence ^ _{connected the m} | _{t of a cold trap} .

the use according to the invention of a getter 45 is equipped to prevent back diffusion of oil vapors

metal in connection with a diffusion pump for and which is capable of medium volume

the removal of a fast, neutral particle mina at pressures of 10 ~ ⁸ to 10 ~ ^lo mm Hg.

bundle also taking into account the teaching of pumping. The diffusion pump is in series with

the aforementioned USA patent is not switched to the main recipient and enabled

suggested. 50 continuously the getter metal surface and the

The use of a getter metal can also be used to pump out recipients, whereby an equal

sets weight pressure already in connection with high vacuum pumps, which is different from the base pressure of the

known, but the known applications under- diffusion pump, from the leaks in the

all differ essentially on the pumping system of the invention and depend on other factors,

proper procedures. 55 equivalent pumping equipment can be used in place of

For example, British patent specification 768 003 describes the diffusion pump can also be used, a process that consists in creating freshness in a room, gases entering the recipient hit the getter metal surface through continuous evaporation and deposition and are indirectly adsorbed by the getter metal layer on the inner surface .The rate of desorption of this space to maintain a vacuum. It should be in the range of about 10 to 100 particles per 6c due to the continuous evaporation and square centimeter and second for relatively pure or condensation of the getter metal, the gas that absorbed into unsaturated metal at pressures in the range of a previously precipitated getter metal 10 ~ ⁸ up to 10 ^-10 mm Hg. These speeds are enabled by the getter metal that follows later, allowing the gases to be pumped out, which are closed with this. Accordingly, in contrast to the method according to the invention, there is no desorption rate from the getter layer with the diffusion pump. If there is a sudden desorption of the break-in of gas particles or ions in the gases enclosed by the getter metal. Recipient briefly occurs, such as B. as a result of a

7th 8th

Impulse discharge of accelerated particles, hit with a pump suitable for the pumping method according to the invention, therefore these particles can be connected to the getter metal surface,
and are completely adsorbed there without the equilibrium pressure increasing noticeably, as long as ^{the adsorption capacity of the metal in large containers in the area below 10 ~ e} mm Hg does not exceed the adsorption capacity of the metal. When the overpressure generating under conditions that degassing of the wall top gas breach is over, the gases with the surface and other surfaces within the container will accomplish speed or a slightly higher rate, e.g. B. continues to be expelled by means of a diffusion speed, and thereby pump. Where the evacuated space or container is to be used for a complete removal of the gas ingress for experimental purposes or test purposes without a noticeable increase in the equilibrium pressure, such as e.g. B. in vacuum technology. in studies of the earth's outer space, in the mass

The invention enables pumping at pressures spectroscopy, for plasma devices or for cores below 10- "mm Hg. As a result of studies, particles other than air or the usual desorption of gases from the getter metal surface also tend to be released together with residual gases with a diffusion pump to be present during or degassed impurities, most of the gases entering the gas ingress when such particles and gases often comprise gas ions, same pressure are adsorbed immediately. B. diatomic or dissociated hydrogen, surfaces, which is otherwise usually carried out, 20 deuterium and tritium. These particles and gases to degas vacuum devices. If the can lead to an arbitrary thermal movement out-pressure of the newly emerging gas above the pressure, however will you be an initially geric If the metal had previously been degassed increases, the getter metal continues to adsorb gas over an energy spectrum, and consequently have an inertial vacuum line whose large capacity for these gases makes this almost difficult or indeterminate. Unlimited particle capture. The desorption-adsorption equilibrium and discharge with negligible back diffusion in weight shifts only very slowly, so that after the vacuum space itself is practically particularly additional gas adsorbed by a gas intrusion, when the previously mentioned light gas has become, the desorption pressure is almost particles remain unchanged, hydrogen, deuterium and / or tritium remains. For example, it has been found that the walls are present 30 since the arbitrary thermal of a closed space of 7500 cm ² inner surface moving speeds of a pressure of 10 ^-7 mm Hg 0.1 to 0.2 microns ten states are extremely high even in relatively unerregbci . It is clear that in order to be able to pump liters of hydrogen and still obtain the most favorable equilibrium, the number of gas will desorb completely at a net speed of collisions between the gas particles or on non-uniformity on the surfaces trapping through the vacuum line of the diffusion pumping system is kept to a minimum. must be, since the possibility of back diffusion

Due to continuous pumping with the diffusion this is particularly large.

pump will produce a uniformly low pressure in which the critical conditions under which vacuums

Recipients are obtained, even if larger gas incidents have to be maintained, both

brüchc intermittently in the metal with a device 40 for example for plasma devices in which

velocity are adsorbed, which is greater than that of the charged particles within a suitable range

Desorption rate is. Order of electric and magnetic fields in

On the basis of the figures, the exemplary embodiments of a vacuum chamber are included. In general

To represent the invention, the invention is to be explained in more detail, the vacuum container must be set to a base pressure of

will. 45 10 ~ "mm Hg or below excluding the central

F i g. .1 shows a vertical section, partially schematic, plasma contained therein are evacuated. There get table by a preferred embodiment of a charged particle because of the magnetic guiding device for evaporation and continuous field not deposited directly in the central plasma area of getter metal in a vacuum that can be conducted are numerous processes especially for use in a getter pump, 50 used to inject neutral particles. To the Beiin The game carried out the process according to the invention can play directed particles from high-energy can be, is suitable; neutral particles, such as B. hydrogen, deuterium

F i g. 2 shows a longitudinal section of the liquid and tritium, energetic by collision

chilled, in Fig. 1 shown, unit for supplying beams from charged particles with those from new-

of the getter metal; 55 neutral particles or through charge exchange with

F i g. Fig. 3 shows partially schematically a cross section of charged particles obtained with the entrance

by an ion pump, which is responsible for the continuous in the corresponding area by an electric and

Vapor deposition and coating of getter metal on the magnetic field can be achieved. Ions and

Cathode plates are set up and in which the inven- tive particles are located within this range

methods according to the invention are practically carried out by plasma charge exchange or by ionizing

can; Received bumps and other effects. Some of the newly

F i g. Fig. 4 shows a longitudinal section through a central particle running completely through this area

Liquid nitrogen-cooled cold trap, the preferred and must be used together with the charged particles

wise at the inlet of an oil diffusion pump and any impurities are removed,

can be closed. 65 For the most effective procedure in plasma

For the practical implementation of the invention directions of the type described above are the

a recipient or a container is usually arranged in parallel alignment in front of the pumping devices,

seen, the evacuated to lower vacuum pressures and around the residual beam of the charged and / or neutral

To collect particles so that most of the particles The diffusion pump remains on continuously. or gases are trapped in ahead of time, but no additional getter metal is made which they reduce their speed and randomly evaporated onto the surfaces. If any borrowed to wander through the container. The vacuum space allows quantities of particles to penetrate into the pumping space can form a common space 5 with the pump space and on the getter metal surfaces as a result, however, when, as mentioned earlier, a mix of particles encounter motion, they will be absorbed If the jet is sucked off, a wide-open opening is desorbed again, corresponding to the adsorption of some depth is preferred to an intake before desorption equilibrium of the metal, and be to facilitate the first collisions. This possibly as a result of an arbitrary movement in the Problems are not only occurring for plasma confinement alone and thus removed from the diffusion pump inlet characteristic, but they also occur in acceleration. Short-lived gas ingresses occurring in the like and other devices with high particle energy pump cavity enter, also hit the on. Where there is a disorderly or thermal moving getter metal surface. Instead of the pressure as it is in test fields, where charged levels are increased in relation to the size of the gas penetrations, Particles are normally absent to gases in the 15, the whole amount of gas is mostly immediate Introducing the pump space, a large opening is adsorbed in the - after each gas particle only a few Relation to the diameter or to the width of the joints against the getter metal surface Pump chamber also preferred to have the inlet - until the surface is saturated. The desorp probability to increase. According to the tion speed grows instead of them in the behavioral process According to the invention, in the simplest 20 nis to the increasing number of adsorbed particles Words and expressed in FIG. 1, one would increase only in a non-linear relationship Vacuum housing 11 is provided, which by an OfF- by a few percent of the gas ingress as a result of bemmgl5 with a vacuum container 13, the newly found affinity of with which it is connected in a vacuum-tight manner. The getter metals for large amounts of gas at low Pump housing 11 determines a recipient or 35 pressures. By continuing the suction with the Pump chamber 12, and the inner surface 116 of the diffusion pump or with others a pump housing 11 has a getter metal, which, although effect-exerting devices are then the It is not necessary to use an additional adsorber device from the gas ingress by means of vapor deposition 27 can be applied. In addition to the beer gases, if they are now desorbed again, surfaces 116 exerting a pumping action and in 30 are removed without a noticeable increase in equilibrium in general at the pressure opposite the inlet 15.

At the end of the pump chamber 12 is the outlet 117, The ability or affinity of the getter metal that

to the pumps, such. B. to adsorb a diffusion gas ingress is only through the

pump 118, leads. Capacity of the metal in terms of gas absorption

In the practical implementation of the method 35 is limited, the capacity being approximately 10 ¹⁴ to 10 ^1B

According to the invention, the pumping action consists of particles per square centimeter of collecting surface

exercising surface 116, which consists of getter metal, is. The ability of a given device

generally degassed first and the pump chamber will adsorb all particles of a gas intrusion,

by means of a pump, such as. B. a diffusion is therefore of the total area of the used

pump 118, usually along with the 40 getter metal to be evacuated. In practice, gas

the vacuum cavity, the pressure increases by a factor of 10 in response to a pressure drop

half 10 ~ ^B mm Hg evacuated. For the most part, or 100 or more will cause it to be completely adsorbed

becomes the pumping surface 116 and thereafter at a rate equal to that of the

continuously coated with getter metal, the vacuum line of the diffusion pump depends on,

by a continuously operating vapor deposition 45 sucked.

Device 27 is used to obtain a pumping effect, in particular when using the metals, through which the vacuum cavity molybdenum, tungsten, tantalum, zirconium, titanium, niobium is pumped out than to an equilibrium pressure. Getter on a surface in the form of an other hand, the coating of at least 10 ~ ^B cm thickness can be extended by pumping a lot of equilibrium pressure with the diffusion pump 118 50 gaseous hydrogen, which is about 10 ¹⁷ particles are maintained alone. At the end of this comparison, for every square centimeter of the wall travel section, which can include degassing through a heating surface at an equilibrium ^{pressure of approximately one, the equilibrium 10 ~ 8} mm Hg will be adsorbed without the pressure being weighted with the diffusion pump 118 maintained solely as a result of the adsorption-desorption equilibrium. Usually the diffusivity will rise above 10 ~ ⁷ mm Hg. The whole gas pump can be a conventionally designed pump, with quantity will quickly after only a few bumps per exception that it adsorbs a cold trap or other molecule against the getter metal surface. Has separating devices to avoid back diffusion. The adsorption-desorption equilibrium for andes oil or pump liquid in the case of lower gases than diatomic hydrogen changes pressures. 60 little under the circumstances listed above,

After the required equilibrium pressure has been reached, since it is more easily adsorbed and more difficult to desorb, the procedure in the will be. Other getter metals that are used vacuum cavity started, that is, the pumping chamber, but for which exact values are not available, is opened to the cavity to be evacuated, are barium, aluminum and rhenium,
or if it is already open, attempts 65 in FIG. 1 is a preferred embodiment or applications within the vacuum cavity of one for performing the inventive concept. The pumping chamber is made up of a device which can be used in practice and which is generated during evacuation. provided, which has a pump chamber in which getter

11 12

metal is deposited on the walls, and the wall 17 is passed through and with the rollers 48 are also connected to or 49 for continuous evacuation, to be vacuum-tight, a diffusion pump or other pumping device has the use of liquid metal seals is equipped. as particularly suitable and particularly tight

An elongated cylinder II closes a recipient 5, which has been tried and tested. For example, a metal assembly or a vacuum chamber 12, the upper end of which is composed of 62.5% gallium, 21.5% indium and 16 ⁰ I ₀ opens into a vacuum container (not shown), tin, which melts ^{at about 10 0 C} , in practice as indicated by walls 13. The soil which proved particularly beneficial.
Chamber 12 is closed by a removable base plate J4. The same vacuum is closed between chambers 12, which are also maintained as the end limits of a 10 and 16, as this is determined by the two wire vacuum chambers 16, which are connected to one another by the cylinder 17 feed tube 31 , serves. The cylinders 11 and 17 are arranged with what is effected by a selection of the size of the fed their flanges 19 and 21 on both sides of the wire, which has a tolerance of ^B / ₁₀₀₀ or base plate 14 and in the pressure-tight fit less with respect to the Wire feed tube 31 is screwed together seat by means of bolts 18, 15 having. In addition, the wire 46 is degassed before it is introduced into the feed unit 27, or 21 seals 22 made of deformable metal, which is water-cooled between the base plate 14 and each of the flanges 9, as is arranged, for example, by ohmic Er. The second chamber 16 can be heated via a connection to a current source 51 at its lower end by means of a dedicated supply line 50. This feed line 50, which can be removed from the end plate 23, is closed and is passed through the end plate 23 at a vacuum-tight, insulated point 52, preferably with a further pump 24, and is connected to an outlet pipe 26. Coil holder 53 for the carrier coil 47 connected.

A water-cooled getter supply made of a conductive metal is made of a conductive metal and is screwed into the base plate 14 opposite the end plate, as is generally the unit 27. 25 shown at 54 is isolated. The power source 51 is. The power supply unit 27 is connected in cross section to the end plate by means of a contact 56. 2 shown. It has a massive plug 28 which is provided with a wire in order to close a circuit, its current winch and which encloses the wire 46 in the conductive path. The wire 46 base plate 14 can be screwed in. A bore 29 extends through the plug as a result of the current flowing through it, and its resistance is heated. With regard to the common thread perpendicular to the plane of the outside around the production of the material of the feed wire 46 leading. A long, centrally arranged one is to note that this wire is a getter metal supply pipe 31 made of metal in a tight fit or a combination of several getter metals can be arranged in the bore 29 and extends. For the adsorption and pumping processes for a certain distance into the vacuum, the continuous evaporation of the compound 12. Suitable pipes 32 and 33 are guide wire and are arranged centrally around the supply pipe 31 during the subsequent process and the metal vapor is deposited In the pump both are a piece in the upper part of the plug 28 cavity have sunk titanium, tantalum, tungsten and, with the outermost tube 33 less deep than molybdenum, as well as zirconium, niobium, thorium and uranium, the middle tube 32 is sunk. Entry and exit 40 highlighted as ideally suited,
Inlet openings 34 and 36, which are located under the base of the feed wire 46, which is located from the upper plate 14 in the plug 28, are to the cooling end of the feed pipe 31, to a high medium supply or discharge in the pipes 33 To heat the temperature, devices are provided or provided. A suitably shaped tip 37 can be seen to bombard this wire with an electron beam to the outer tube 33, as indicated generally at 38-45. A cathode ray generator 59, which is indicated, fixedly connected and designed to have a filament 60, is arranged over the tip 37 as a unit with the connected supply line, e.g. B. by means of cathode holders 61 which form in tube 31. Cooling water or an equivalent of the base plate 14 are held insulated. The Er cooling liquid, which is allowed to heat the inlet opening 34 of the thread 59 for electron emission, flows upwards between the tubes 32 50 passes via feed lines 62, which are connected to the holders 61 and 33, is diverted through the tip 37 and flows on the lower side of the base plate 14 connected down between the tubes 32 and 31 and to are. These leads are outwardly through the outlet port 36. Bushings 63 which are sealed with the inlet and which are arranged in the end-to-end outlet oil channel 34 and 36 are pipelines 39 plate 23, guided and connected to one or 41. These pipelines lead to a suitable power source 64 connected, one of which is externally through the chamber wall 17, as is generally the case with Pole, at the earthed housing potential. The 42 or 43 is indicated in order to facilitate a connection with electrons emitted by the filament 60 on an external water supply 44. the molten ball or mass 72 roughly in focus

A wound on a rotatable metal reel 47 through a net 66 placed on a bias voltage, the

tcr wire 46, which consists of the getter metal which is arranged 60 coaxially around the tip 37 and of elec-

Should not be beaten, is continuously in trically conductive, with the holders 61 connected

the wire feeder ear 31 is held by means of two conventional carriers 67. The network 66 is thereby

Externally driven feed rollers 48 and at a negative potential as well as the current

49, the source 64 to a light promotion of the wire and therefore also held like the thread 60,

serve, supplied. 65 In addition, the getter wire 46 is on the

While numerous other conventional potentials of the base plate 14 are also maintained, as at

Devices can be used around which 68 is generally referred to, is grounded, whereby the

rotating drive shafts 57 and 58, which by the potential difference between the thread 60 and the

13 14

exiting tip of the wire 46 can be accelerated with the preferred embodiment of the electron beam to this tip. hold than older coatings with lower vacuum der The impact of the electron beam causes compression to degas. In most cases it will Vaporize the tip of the fed wire 46 as evacuated by the entire system with the device the advantageous getter effect of the fresh will be described in more detail below in connection with mode of operation 5. To prevent beaten metal from being used. This verdict the metal vapors developed in this way will drive the evacuation of the vacuum cavity The vacuum chambers outside of the main pumping are preferred because it is much faster than others Contaminate space 12, a circular plate procedure will lead to the goal and because of this effect 69 preferably at a distance from the wall 13 by means of this normally through the getter apparatus anchored supports 71 arranged. All of this is brought out. At the end of this pumping period, in The devices just described serve as the preferred coating that is still sufficiently fresh in all cases Apparatus for the present invention, so that a further evacuation in the travel. Low pressure area after the getter pump

If the loading 15 itself is switched off during the process of pulling on, with the method according to the container walls or other surfaces within the invention, which is described in more detail below Pump chamber 12 with the getter metal in preparation is reached.

to the method according to the invention and possibly with the device for vapor deposition of a metallic

At the same time as the evacuation of the chamber, the diffuse getter coating, which was described above, is not used, as explained above, a preparatory evacuation is first performed, then the vacuum evaporation device works by removing the upper and lower vacuum as follows: The evaporation chamber 12 is first chamber 12 and 16 first during a lengthy period by known devices, such as. B. (not shown) an outside length of time to a pressure of 10 ^-4 mm Hg or semi-disposed pump, is pumped to a less, usually pumped to the in pressure of 10 ~ ⁴ mm Hg or less, 25 the walls of the chambers enclosed gases to avoid direct discharge when the. to drive out. During the period this pre-cathode ray generator is energized. Then preparatory evacuation or during the later cooling water through the getter supply unit 27 is supplied to the power source 51 Einrichtund durchgeschickt, whereby water at room temperature is suitable for heating the supplied wire 46 to one or even a higher temperature as long as a temperature of about 2000 ⁰ C by ohmic It is, as its flow rate within the heating, the precise temperature of the chamber 12 being sufficient to remove the heat from the melting point of the case in question sufficiently quickly. The feed rolls 48 depend on the turned wire material. All gaseous and 49 are then set in motion and the incandescent impurities are normally heated at this filament 60. When the filament 60 has been heated, 35 temperature is driven out, and the getter wire 46 is heated by the stream of electrons which is exiting on the exiting one, then having a purity which impinges with that of the wire 46, the wire tip and melts it. The starting metal is identical. The whole of the self-supporting molten mass or vaporization unit is first actuated as previously described ball 72 forms on the tip of the wire, and this ball vaporizes metal in line of sight from the surface tension 40 the melted one is held together. The molten ball 72, ball out onto the walls and other surfaces, shields the tip 37 of the feeder from those located within the chamber 12. That from the electron bombardment. A sufficiently large, purified, pure getter metal coats the walls. Amount of energy is continuously melted and absorbed on the surface of the gas scene, concentrated in order to vaporize it with a velocity of chemical sorption on the walls due to the chemical sorption. and physical absorption,
speed of the wire. Of course, other procedures can be used

led wire will be used immediately behind "the ball" to line the walls of the evacuated to provide a getter coating thermally and electrically through the water-cooled cavity or, Tip 37 protected, without which the ball 72 quickly 50 as already stated above, it can also would burn off because the wire would be too thin to start with walls made of a getter material and would then no longer be able to exist, be provided and by means of degassing hold melted ball. elevated temperature from the adsorbing gases

When the vaporizer that is cleaned above. Also, an enlargement that has been described is only used as a device for up- 55 pumping capacity in the formation of the recipient vaporizing getter metal onto the surface 11 of the like a conventional clay getter pump, e.g. B. is used by the pumping chamber to prepare the Penning discharge type according to the invention shown in Fig. 3, the getter wire with flat cathode collector plates are reached, in the feed mechanism and the cathode ray a water-cooled getter metal feed unit 27, generator only for so long operated together until a 60 as described above is inserted. Has formed coating of the desired thickness. This getter metal supply unit 27 is best then the corresponding devices are switched off with their water-cooled tip 37 in a vertical position. A coating of at least 10 ~ ^B cm thickness position located within the pump chamber 73, is, in general, for the purposes of the present When the molten ball 72 is formed, beer invention sufficiently. Most often, the over- 65 is found in the line of sight of the counterparts vapor-deposited onto an old coating that was used for prior pumping out of the overlying surfaces of the collector electrodes 78, since in this case the getter metal can be done faster and more easily is to form fresh, pure coated inner parts of the recipient. the

15 16

Electron source and all other additional equipment. The use of the surface

As a result, the getter metal source which evaporates the getter metal supports the diffusion pump

can be the same as in Fig. 1 shows the reduced possibility for gas penetration into the

are. To diffuse back into the main vacuum chamber. The Get-

The embodiments described above are 5 terpump can be switched on for a short period of time Procedure if z. B. perform a leak in the outside atmosphere. In addition, a second must also occur opposite or if additional containers are connected to the pump in connection with the pump chamber 12 via a 10 the system. Under such UmAuslaß 117 be provided to this space on the stands, the equilibrium pressure is pumped out to a required outlet pressure. Since this factor increases by 10 ³ or more and the volume of the pump should be able to pump larger quantities up to the amount of the added gas will be larger than the reaching of the starting pressure mentioned getter metal can absorb, a commonly used oil diffusion 15

pump 181 is generally the most suitable device. example For purposes where the pumping method is based on the

Invention is used, ie if pressures below a stainless steel vacuum container with half 10- ° mm Hg are to be achieved, the volume of 701 must be ^{baked out at 400 0} C and diffusion pump with devices, 20 evacuated by an oil diffusion pump. In order to avoid a back diffusion of the oil molecules into the pump pressure of 1Ό ~ ^β mm Hg when using the space. Various cold traps are obtained by diffusion pumps alone if the suction for this purpose, as is well known, has been suitably channeled by means of a liquid nitrogen containing and back diffusion has been cooled down to pressures in the cold trap, the cold trap ^{preventing a range of 10 -8} mm Hg. A special somewhat different construction, of which the above embodiment of a separating or cold trap 18 has been described, but has the same function as in the cross section in FIG. 4, the arrows having this. After molybdenum has evaporated, designate the direction of gas flow to flow out of a getter pump, which was identical to the embodiment previously described a conduction cooled barrier 82 around, in the container and on a container 83, the liquid nitrogen 30 for about 1 hour , the pressure of the system dropped to, over, with that with the oil of the diffusion about 1 x 10 " ⁸⁰ mm Hg. The capacity of the pump pump charged gas entering inlet 84, the arrangement of the system was tested by gas-called built-in parts of the cold trap flows through, in the form of hydrogen intermittently into the container into which the oil condenses and finally the gas was passed to the outlet 86 without the getter pump being in operation. The following data were obtained:

The inventive method is using the preferred output container content described above is approximately 701

guide forms of the apparatus practically following - surface projection of the with getter -

measurements carried out: the recipient and the main metal-coated wall about 7500 cm ²

vacuum chambers are first measured up to the desired 40 specific area

Equilibrium pressure evacuated by the getter argon adsorption on a

pump or ion pump is used, which has a molybdenum coating at lower

continuous precipitation of getter material at temperature greater than that

generated the electrode collector plates. During this 20 times the area

Duration is a pumping out with the diffusion pump 45 surface projection

not necessary. Once the equilibrium pressure pressure ^<10 mm Hg L0

is reached, the getter facilities and / or "'' '" graze.

the ion pumping devices are switched off and the "amount H ₈ , -the per · gas pulse _{entered- inM} _.,

Diffusion pump connected. At this time, ^let ^ ^{αε > 4} " ^{10 tede}

in the most advantageous ways of working the dike 50 duration for a gas surge <1 second

weight pressure in the range of 10 ~ ⁷ to 10 ~ ^e mm Hg pressure increase per gas impact (walls

or below. In this pressure range adsorbed reactivated) 1 · 10 ~ ⁸ mm Hg

the degassed getter metal surface slightly larger Measured equivalent pump

Gas quantities, if a short-term overpressure- speed 4 · 10 * 1 per

occurs, d. H. an increase by a factor of 10 or more - 55 seconds

the pressure, since an unexpected affinity of the getter- Required H ₂ amount per liter container-

metal at pressures was found at which in the content, to the saturation of the

generally only desorption was expected to achieve coating; d. H. a

as discussed in more detail above. After a pressure increase of 1 x 10 ~ ^B mm Hg

the getter metal begins _to cause adsorption immediately about 1 mm / l

again to desorb the gas. With a suitable choice

After the above values have been checked, the getter pump unit was switched off in relation to the recipient volume and the diffusion pump removed practically all of the hydrogen in the system until the gas was desorbed from the getter metal, and in gaseous form As a result, 65 pressure was about 1 x 10 ~ ^B mm Hg, whereupon the water is a continuous start-up of the getter flow was interrupted.Then a pump was not required for a long time if the diffusion pump alone continued to evacuate observed that the diffusion pump S seconds

took to decrease the pressure from 2 to 1 x 10 ~ ^e mm Hg, seconds from 2 to 1 x 10 ~ 1 mm Hg, and 570 seconds from 2 to 1 x 10 ~ ⁸ mm Hg. Hydrogen was then intermittently admitted into the container in the size described above, that is to say 4 × 10 ^{7 ae particles.} In each case, the pressure rise was about 1 x 10 ^-8 mm Hg after the first amount of gas was introduced, proving that the hydrogen was almost completely adsorbed immediately by the getter surface. The desorption and the removal of the desorbed gas took place again by evacuation with the diffusion pump during the indicated times, the speed being determined by the vacuum line of the diffusion pump system. is

Claims (4)

Patent claims: 1. A method for removing sudden gas ingress in a recipient, in which an equilibrium pressure of less than 10 ~ ^e mm Hg is continuously established by means of a vacuum pump, characterized in that such a getter metal layer is deposited in the recipient, which the gases at these small as Pressures absorbed much faster than desorbed, with the absorption capacity of the getter metal layer being higher than the number of particles in such a sudden gas ingress, so that the equilibrium pressure is initially maintained by absorption of these particles on the getter metal layer, and that after absorption by the getter metal layer now Gases desorbed again more slowly are then removed by the vacuum pump, the connection of which is located in the vicinity of the getter metal layer. 2. The method according to claim 1, characterized in that the getter metal layer is continuous is renewed. 3. The method according to claim 2, characterized in that the renewal of the getter metal layer takes place by vapor deposition of additional getter metal on the layer, the Vapor deposition obtained by electron bombardment of a getter metal wire located in the recipient will. - 4. The method according to claim 1 to 3, characterized in that the vacuum pump consists of a Old diffusion pump consists, the inlet lines of which are cooled by a cold trap, whereby back-diffusing oil is condensed and returned to the pump. 5. The method according to claim 1, characterized in that the getter metal consists of the following Group selected is: titanium, tantalum, tungsten, molybdenum, zircon, niobium, rhenium, and thorium Uranium. 6. The method according to claim 1 to 5, characterized in that at least part of the getter metal surface is kept at a negative potential for the purpose of accumulating positive ions. 7. The method according to claim 1 to 6, characterized in that when using hydrogen as a gas, the getter metal is molybdenum in a manner known per se. 8. The method according to claim 1, characterized in that the gas surges before adsorption Do not exceed the pressure of the recipient by a factor of more than 10. Considered publications: German Auslegeschriften No. 1065 561, 1 046 249; British Patent No. 768,003; Book by Martin Littmann, "Getterstoffe", Winter'sche Verlagshandlung, Leipzig, 1938, p. 44; Book by S. Inananandra, "High Vacua," New York, 1947, p. 293. 1 sheet of drawings 709 678/61 10.67 © Bundesdruckerei Berlin