CN1082668A

CN1082668A - Improved high-capacity getter pump

Info

Publication number: CN1082668A
Application number: CN93106487A
Authority: CN
Inventors: 布鲁诺·菲拉里奥
Original assignee: SAES Getters SpA
Current assignee: SAES Getters SpA
Priority date: 1992-07-17
Filing date: 1993-05-31
Publication date: 1994-02-23
Anticipated expiration: 2013-05-31
Also published as: RU2082251C1; ATE141025T1; ES2090998T3; RU94045979A; ITMI921753A0; EP0650639B1; JP2655012B2; DE69303901T2; CA2128416A1; KR950701131A; WO1994002957A1; CA2128416C; KR100203018B1; ITMI921753A1; JPH07509036A; IT1255439B; EP0650639A1; DE69303901D1; CN1057147C

Abstract

A kind of improved high-capacity getter pump that produces and keep vacuum that is applicable to comprises: many porous thermal sintering blades of making by the getter material of non-vaporising, and blade has first main surface; Second main surface with 0.5-5.0mm thickness first major surfaces in parallel and alternate; Be arranged at described blade among the housing and be separated from each other, thereby form an air passageways with the adjacently situated surfaces of the adjacent blades of alternate 0.5-10mm distance mutually.

Description

Improved high-capacity getter pump

The present invention relates to a kind of improved high-capacity getter pump, this pump is suitable in such as a ultravacuum chamber or produces and keep vacuum in a high-energy particle accelerator.

That suction pump is known in the art and be suitable for producing and keeping vacuum.In U.S. Pat 3,780, first commercial successful suction pump described in 501 adopted a pleated metal strap in a housing, be embedded with air-breathing metal in the belt.In U.S. Pat 3,609,064; 3,662,522; 3,961,897; The other example of this class suction pump has been described in 4,137,012.Though the suction pump of these forms has been obtained success widely and obtained admitting of market commercial, it is defectiveness still, promptly defines gulp capacity in a definite volume.

For increasing described gulp capacity, someone's those (tablets) similar coccoid getter material of proposing in pump case, to pack into simply and being adopted in granularity and the medicine trade once, it is 5-10mm that this ball typically is diameter, high 2-10mm's is cylindrical.But when inserting this ball in housing, it is very undesirable that air arrives the passage of loose air suction structure.It is that these beads might form undesirable discrete particles that the defective of described bead is used in another restriction, moreover (especially when the activationary temperature of used getter material hangs down) between possible burn period, because the possible high exothermicity of getter material also can make this loose structure produce safety problem.

In view of the above, first purpose of the present invention is to provide a kind of improved suction pump of eliminating one or more above-mentioned defective basically.

The improved suction pump that another object of the present invention is to provide suction pump a kind of and of the prior art to compare and has the higher air-breathing rate of per unit volume.

A further object of the present invention is to provide suction pump a kind of and of the prior art to compare the gettering quantity with higher per unit volume.

Attached purpose of the present invention is to provide a kind of improved suction pump that pleated coating belt also need not air-breathing material ball that neither adopts.

With reference to following description and accompanying drawing, other purpose of the present invention also can be understood by those of ordinary skills.

Under situation the most widely, the present invention relates to a kind of being suitable for and in such as ultravacuum chamber of an energetic particle speed device neutralization, produce and keep vacuum, described pump comprises many by the made porous thermal sintering blade of the material of non-vaporising, this blade has:

ⅰ) first main surface;

Be second main surface of 0.5-5.0mm with described first major surfaces in parallel and phase spacing basically ⅱ);

Wherein with described vane collocation in a housing and by one being that the distance of 0.5-10mm and the formed air passageways of the adjacently situated surfaces of separated adjacent blades (empty middle ware apart from) are separated from each other substantially.

Air passageways between adjacent blades allows air molecule to enter the air suction structure of porous with very fast speed, and the high porosity of porous thermal sintering blade has improved the efficient of absorption of air preferably with respect to pleated belt and bead of the prior art (or sheet).

Described blade radially is arranged in the described housing aptly, thereby forms an internal channel with its inner end.According to suction pump of the present invention further also be provided with one be used under the activationary temperature and the heater that under the desired operating temperature blade is heated and one be used for described housing is fixed in a flange plate on the vacuum chamber.

The shape of the porous thermal sintering blade of pump in accordance with the present invention can be plane (especially rectangle and the taper of choosing wantonly and/or an oblique shape), concave surface and combination thereof.In addition, the density of described blade is 1 to 5g/cm ³, preferably 1.5 to 3.5g/cm ³, surface area is 0.05 to 1m ²/ g(is preferably 0.1-1m ²/ g).

Can in various vacuum systems and equipment, be used to keep vacuum according to suction pump of the present invention, for example, enclosed vacuum container (as: Dewar or the vacuum box that are used for the liquid transfer pipeline), particle accelerator (for example synchrotron) and ultravacuum chamber; This new suction pump can be kept as 10 ^-6, even 10 ^-12Millibar (10 ^-10Handkerchief) high like this degree of vacuum.

Can adopt the various not evaporating getter metals to make pump in accordance with the present invention, as zirconium, titanium, hafnium, tantalum, thorium, uranium, niobium and composition thereof and these metals mutual and with the alloy of other metal, this alloy yes or no intermetallic compounds.These air-breathing metals can separately or mix ground one with other material and for example mix ground-use with antiwelding agent.Be used to make described porous thermal sintering blade non-vaporising air-breathing metal example but be not construed as limiting serial as follows:

A) as U.S. Pat 3,203, the 901 described 84%Zr that contain, its surplus part is the alloy of Al;

B) according to U. S. Patent U3,584,253 with Zr, Ta, Hf, Nb, Ti or U be the basis a kind of metal component;

C) according to U. S. Patent U3, a kind of metal component based on the Zr mixture that contains the Zr-Al alloy of example 3 in 926,832;

D) as U. S. Patent 4,071, the intermetallic compounds Zr described in 335 ₂Ni;

E) according to U.S. Pat 4,269,624 Zr-M ₁-M ₂Alloy, wherein M ₁Be V or Nb, M ₂Be Fe or Ni;

F) according to U.S. Pat 4,306,887 Zr-Fe alloy;

G) as U.S. Pat 4,312,669 described zirconiums, some alloys of vanadium and iron, and other zirconium and vanadium and a small amount of transition metal-as manganese-alloy;

H) as U.S. Pat 4,907,948 described zirconiums, some alloys of titanium and iron.

According to a preferred embodiment of the invention, mix the air-breathing metal of selecting described non-vaporising mutually with independent Zr and/or independent Ti randomly from Zr-V-Fe alloy and Zr-Ti-Fe alloy, these materials finally all are hydride randomly.At UK Patent Application GB2, disclosed composition in 077,487, the claimant has confirmed the special benefits of this thing with its name, draw from following:

I) getter alloy of the non-vaporising of a kind of Zr-V-Fe of three kinds of particles has a kind of composition (by weight), and when drawing Zhang San's phasor, said composition is in a flex point among the polygonal on the following point (by weight):

a）75%Zr-20%V-5%Fe;

b）45%Zr-20%V-35%Fe;

c）45%Zr-50%v-5%Fe

II) a kind of air-breathing metallic of the non-vaporising of selecting from Zr and Ti, wherein the average particle size of Zr and/or Ti particle is less than the average particle size of alloy grain.

This composition is sold by the claimant, is referred to as " SAES St172 ".

A kind of superior method of making the porous thermal sintering blade of pump in accordance with the present invention at first from above-mentioned mixing, may further comprise the steps:

A), mix mutually with independent Zr and/or independent Ti randomly and mix the air-breathing metal for preparing described non-vaporising mutually with a kind of dilatant with the form of the bulky powder of Zr-V-Fe and/or Zr-Ti-Fe alloy grain;

B) described bulky powder (or consequent mixture) is injected a mould and thermal sintering.

Described alloy grain preferably has the 0.15m of being equal to or higher than ²/ g and 0.25m preferably ²The presintering area of/g, presintering granularity reach 400 μ m, and preferably 1 to 128 μ m better is 1 to 50 μ m.

Described Zr and/or Ti particle have the average particle size that is preferably 1 to 55 μ m successively, and 0.1 to 1.0m ²The surface area of/g, wherein the weight ratio between alloy grain and described Zr and/or the Ti particle suits between 10: 1 to 1: 1.

The thermal sintering temperature that it has been generally acknowledged that a kind of satisfaction is between 700 to 1200 ℃, keeps a few minutes to several hours, because the time that low again temperature need be grown; The thermal sintering time should be able to produce stablizing on the size.

Dilatant should be suitably a kind of organic and/or inorganic salts, wherein be included in the nitrogen and/or the phosphorus that decompose fully under the thermal sintering temperature, urea for example, the azo dicarbonamide and/or the carbamate of aminoquinoxaline for example, the getter material of non-vaporising (preferably 2-10%) 0.1 to 15% amount by weight relatively.The molecular formula of azo dicarbonamide is as follows:

NH ₂-CO-N＝N-CO-NH ₂

Heater can be arranged within the housing of suction pump or outside.Can be as U.S. Pat 3,609,064 is described, makes electric current directly flow through getter material, or with conduction or radiation, for example utilize the ultrahigh vacuum quartz lamp, finishes heating.

At last, porous thermal sintering blade should tilt (and the axial plane of pump inclines slightly relatively) mutually slightly, so that by radiation fully.

Following accompanying drawing (Fig. 1-10) only is used to illustrate, and scope of the present invention is not constituted any qualification; Wherein:

Fig. 1 is the in running order schematic representation of suction pump according to the present invention;

Fig. 2 is the amplification view according to suction pump of the present invention along II among Fig. 1-II line intercepting;

Fig. 3 is the perspective view of the part of suction pump shown in Fig. 2;

Fig. 4 is the sectional view according to suction pump of the present invention along IV among Fig. 2-IV line intercepting;

Fig. 5 is according to several sectional views that become the blade at α angle with the axial plane X-X of pump of the present invention;

Fig. 6 is the view similar to Fig. 5, but represents difform blade;

Fig. 7 is the sectional view that is used for a mold of rectangular paddle thermal sintering;

Fig. 8 is shown schematically in the used pumping system of example duration of test;

Fig. 9 is the result who represents several pumping tests with the form of figure;

Figure 10 represents a partial sectional view according to typical pump of the present invention, wherein blade is arranged to different overlapping annular row (crown or chuck shape).

Always referring to accompanying drawing and especially with reference to Fig. 1 and 2, wherein represented a kind of improved non-vaporising suction pump 10 below, this pump has the seal casinghousing 12 of a flanged dish 14, and flange plate 14 has constituted described housing 12 is fixed in device on the vacuum vessel 15.

Suction pump 10 among Fig. 2 has the

blade

18,19,20 of many porous thermal sinterings, and these are in the cylindrical housings 12 by the made blade of the air-breathing metal of non-vaporising.Blade 18 have first plane 22 and be arranged essentially parallel to 24, the second planes 24, second plane on first plane and first plane, the 22 alternate 0.5-5mm of being about apart from t(thickness).Blade 18 can be a rectangle.Such as

blade

18,19,20 and the structure of other all blade all

identical.Blade

18,19,20 and other blade be disposed radially, mutually alternate with adjacent blades be substantially 0.5 and 10mm between a distance " c ".At

blade

18,19,20 and other blade between space " c " constitute air guide channel.

Preferably as shown in Figure 5; make the axis of every blade and the axial plane X-X of pump form a little angle [alpha]; as 1 to 15 °, can protect the inwall (see among Fig. 5 blade 18 ') of housing so at least, this has also just reduced from the possibility of described wall exhaust.Suitably select whole thermal radiation that described α angle also can make blade all radially, thereby avoid the inhomogeneous heating of porous getter material.In addition, total efficiency of heating surface of this layout and the saving of power also be can not be ignored.The shape of this blade can be a kind of straight shape or as the blade among Fig. 6 18 " have very little concavity.In two kinds of situations of the α angular deviation of relative axial direction or concavity, not only increased the heating of blade but also increased the air suction-operated.

Suction pump 10 has first a circular orientation plate 26 of being made by tinsel, radially be provided with on it many as

air flue

28,29,30,31,32 and 33 such air flues.Adjacent air flue (groove) 32,33 is separated by the rib 34 that radially extends on annular slab 26.

The

chimb

36,38 of radial rib 34 can be a distance that equals blade 19 width substantially that axially be parallel to each other and alternate; Described

chimb

36,38 blocks an end of blade 19.Suction pump 10 also has one and is located at such as

blade

18,19, one the second identical circular orientation plate (not shown) at the (not shown) place, bottom of 20 such blades.

Suction pump 10 has many points and is welded in

lath

40,41,42 on the second circular orientation plate circumference that shows expression among the first circular orientation plate 26 and the figure.Same suction pump 10 has thermocouple 47 and lamp 44, is used under activationary temperature and operating temperature blade heating (see figure 10).With power source 46(Fig. 1) the required power supply of supply lamp 44.It is that D(sees Fig. 2 that the inner of blade constitutes diameter), the internal channel that links to each other with air flue.

Suction pump according to the present invention has the adsorptive power than big several times of suction pump of the prior art in a definite volume.Though described the present invention in detail with reference to certain preferred embodiment, also will be appreciated that under the condition that does not break away from the scope of the invention and can also carry out many changes and improvements; Especially the example that provides below only is used for illustrative, under any circumstance all scope and spirit of the present invention is not constituted to limit.

Example 1

" A " be (manufacturing of blade and the assembling of pump) partly

At first, make the thermal sintering blade of porous with the discrete particles of Zr-V-Fe alloy with feature as follows:

-component (% is by weight):

Zr＝70;＝24.5;Fe＝5.5;

-average particle size=1-128 μ m

-surface area=0.25m ²/ g

Then, with alloy grain by weight 1.5: 1 ratio with have the Zr discrete particles of following feature and be 5% aminoquinoxaline (NH by weight ₂-CO-O-NH ₂) fully mix,

-average particle size=1-55 μ m;

-surface area=0.45m ²/ g.

The mixture that generated is added in the right angle carbon mould among Fig. 7, and with 1000 ℃ of temperature sintering 10 minutes; The long 75mm of the blade of so making, wide 20mm, thick 1.4mm.The surface area of this porous thermal sintering blade is 0.14-0.15m ²/ g, how much (visible) areas of blade are about 33cm ², density is 3g/cm ²

In kind make 112 all blades, with described blade radially with two identical stacked rows (in each tube, establishing 56 blades) and with in the angular separation that the equates stainless steel cylindrical shell that to be arranged at an internal diameter be 100mm, and the outside dimension of blade is almost contacted with the inwall of housing (gap=1mm).The surface ratio, promptly the ratio of the volume of the geometric jacquard patterning unit surface of blade and housing is 3.1cm ²/ cm ³, be 58mm by the diameter of the inner formed internal channel of the blade of radial arrangement.V/V, promptly the ratio of the empty volume of all volumes of blade and housing is 0.21cm ³/ cm ³, and quality ratio is about 0.64g/cm ³

" B " be (pumping test) partly:

Shown in signal among Fig. 8, suction pump (GP) is fixed on the vacuum chamber (VC), this chamber is linked to each other with a high vacuum pumping system (VP) by the tube equipment of a kind of known pipeline (C) (pipeline of demarcation).To test vacuum chamber by a main pump group and be evacuated to 10 ^-8The pressure of torr.

Use heating (activation) coaxial with the housing of pump but interior quartz lamp realization suction pump that represent in the drawings.

Opening quartz lamp makes it reach 500 ℃ temperature until air-breathing blade being carried out thermal radiation.This temperature was kept one hour, shut lamp again, make the temperature of getter material reduce to room temperature (25 ℃).With this understanding, a kind of known test gas (CO) from high-purity reservoir (R) is flowed in the pipeline of the pipeline that connects pumping system and demarcation.Control said flow by a ultravacuum (UHV) sapphire valve.Two pressure controller (B-A type vacuum gauge) BAG1 and BAG2 are used for measured pressure value after known pipeline (C) reaches before continuously.

By control valve (V) suitably, the pressure (Pm) of demarcating the pipeline upstream is remained on a constant level (1.5 * 10 ^-4Torr), near the downstream pressure the suction pump (Pg) monitoring several hrs; Described pressure (Pg) is lower than the pressure (Pm) of gas pipeline upstream, and this is because suction pump has absorbed the gas that partly enters volume (VC).The reduction of pumping rate by the increase correspondence of the gas flow that getter material absorbed, and the increase of corresponding pressure (Pg).

According to pressure (Pm) (torr), gas pipeline C(liter/second) (L/S) and pressure P g(torr) over time, can be used as absorb the amount of air (torr * liter) function calculate the pumping rate G(L/S of suction pump).Just as known, the gas flow (Qi) that flows through gas pipeline (C) at a definite point is determined by following formula:

Qi=C(Pm-Pg) (torr * liter/second) (tom * L/S)

The gas flow of this unit time be consistent by the gas flow (time per unit) that suction pump absorbed, the amount that absorbs is by G * Pg(torr * liter/second) represent that promptly near the product of the pressure (Pg) of the pumping rate of suction pump and same suction pump is represented.Can obtain by equilibrium these two amounts:

G×Pg＝C（Pm-Pg）;

Draw thus:

G（t）＝C〔（Pm-Pg（t））〕/Pg（t）

As known, can be by gas flow Qi that time per unit absorbed be drawn at time t place by all gas amount Q that suction pump absorbed time integral,

Q＝∫Qidt＝∫G（t）×Pg（t）dt

Fig. 9 has represented the result who measures, be that the pumping rate of suction pump is as the function of the gas flow that suction pump absorbed and develop, wherein drawn the G(pumping rate) with the Q(adsorptive power) ratio, be that these parameters (line 1) and basis are in U.S. Pat 3, prior art described in 662,522 (SAES suction pump GP200) and comparison with result that suction pump obtained (line 2) of same volume.

Can understand from above-mentioned comparison, according to the pumping rate of improved suction pump GP of the present invention than the traditional high twice of GP200 pump that is based upon on the coated steel band.Can also see that when the pumping rate of two pumps was lower than 100 liters/second, adsorptive power was than the pump height of the corresponding form of the same order of magnitude.The improved suction pump according to the present invention, the getter that has than traditional non-vaporising for a definite vome of shell has obviously high absorption and characteristic performance.

Example 2

Replace carbon monoxide with nitrogen, repeat example 1 once more.In the case, pumping rate and adsorptive power are higher than corresponding standard GP200 pump significantly.

Example 3

With hydrogen (H ₂) replace carbon monoxide to repeat example 1 once more.In this case, the pumping rate of the suction pump after the improvement is more than the twice of GP200.Because the hydrogen capacity of getter material that is used to make the used non-vaporising of pump is than CO and N ₂Want high, so pump absorbed 10 torrs * liter hydrogen (H ₂) and before the point that pumping rate begins to reduce, just stopped test.

Claims

1, the high volume suction pump after a kind of improvement that is suitable for producing and keep vacuum, comprise many by the made porous heat of the absorbent material of non-vaporising around the knot blade, and have:

ⅰ) first main surface;

Wherein, with described vane collocation in a housing with being spaced from each other by an air passageways (empty intermediate space), this passage is formed by the adjacent surface of the distance adjacent blades spaced apart from each other that is essentially 0.5-10mm.

2, pump as claimed in claim 1, it is characterized in that, described blade is disposed radially basically, thereby, also comprises a heater and a fixed flange that links to each other with described housing on it with its inner internal channel of symmetrical longitudinal shaft formation round pump.

3, pump as claimed in claim 2, it is characterized in that, described porous thermal sintering blade has plane (especially rectangle and tapering and/or oblique angle randomly), concave surface and above-mentioned both shape of combination, the axis of described blade with pass described pump longitudinal axis each sheet sharf to plane shape at an angle, described angle is preferably between 10 and 15 °.

4, pump as claimed in claim 1 is characterized in that, the density of described porous thermal sintering blade from 1 to 5g/cm ³, preferably 1.5 to 3.5g/cm ³, surface area is 0.05 to 1m ²/ g.

5, pump as claimed in claim 1 is characterized in that, the getter material of described non-vaporising is from zirconium, titanium, hafnium, tantalum, thorium, uranium, niobium and composition thereof and/or alloy and/or with the alloy of other metal in select, described metal mixes mutually with heat resistanceheat resistant agglutinant randomly.

6, pump as claimed in claim 5 is characterized in that, the air-breathing metal of described non-vaporising is selected from following substances:

The a.Zr-V-Fe alloy;

The b.Zr-T-Fe alloy;

Combine with independent Zr and independent Ti randomly, get the form of zircoium hydride and titantium hydride randomly.

7, pump as claimed in claim 6 is characterized in that, the air-breathing metal of described non-vaporising is the composition that is obtained from following material:

a）75%Zr-20%V-5%Fe;

b）45%Zr-20%V-35%Fe;

c）45%Zr-50%v-5%Fe。

8, a kind of method that is used to make according to the porous thermal sintering blade of the pump of claim 6, wherein:

-preparing described air-breathing metal with the form of the discrete particles of alloy grain, described metal granule mixes mutually with independent Zr particle and/or Ti particle and a kind of dilatant randomly;

-described dilatant is a kind of inorganic or organic salt, and comprising nitrogen and/or phosphorus, this salt decomposes under the thermal sintering temperature fully, and preferably by urea, selects in azo dicarbonamide and the carbamate;

-with pack into a mould and of described discrete particles (or the mixture that is produced) at 700 to 1200 ℃ of sintering temperatures, wherein,

The presintering surface of-described alloy grain is equal to or higher than 0.15m ²/ g is preferably 0.25m ²/ g, presintering granularity to 400 μ m is preferably 1 to 129 μ m, is more preferably 1 to 50 μ m; The average particle size of said Zr and/or Ti particle is 1 to 55 μ m, and wherein the weight ratio of alloy grain and described Zr and/or Ti particle is 10: 1 to 1: 1.

9, method as claimed in claim 8 is characterized in that, described dilatant is an aminoquinoxaline, wherein carbamate by weight the air-breathing metal of described relatively non-vaporising be 0.1 to 15%(to be preferably 2-10%).

10, a kind of method is used at device and/or equipment produces and/or the maintenance vacuum, in the hope of holding it under the vacuum condition, especially holds it in and is equal to or higher than 10 ¹⁶Even 10 ^-12Under the vacuum condition of millibar (mbar), it is characterized in that, described device and/or equipment are connected or be fixed on the improved high-capacity getter pump in the claim 1.

11, method as claimed in claim 10 is characterized in that, selects described device and/or equipment from following equipment:

-vacuum vessel for example is used to transmit the Dewar or the vacuum box of the pipeline of liquid;

-ultrahigh vacuum cavity;

-particle accelerator, especially synchrotron.