DE102007034478A1 - Vacuum housing and method of making an insert for a vacuum housing - Google Patents

Abstract

The invention relates to a vacuum housing, with an insert in a housing wall, in particular as performing an electrical connection, with at least one held in use body, which extends through the housing wall, wherein the insert is an insert made of a polymer Material and a sealing member made of an elastomeric material, and wherein the sealing member (12) seals the body to the insert part.

Description

The The invention relates to a vacuum housing, with an insert in one Housing wall, in particular as an implementation an electrical connection, as a mechanical feedthrough, for sight glasses or for others Vacuum-tight interruptions of the housing wall. It also concerns the invention a method for producing an insert for a vacuum housing.

Technical-scientific apparatus or instruments may be equipped with a vacuum system. Due to the vacuum system, areas of higher pressure (even normal pressure) are separated from areas of relatively low pressure (also 10 ^-9 mbar). For this purpose, a housing with correspondingly stable walls is provided as part of the vacuum system.

Low pressure side and high-pressure side of the vacuum system must be for a variety of purposes and applications related or coupled be. For example, electrical lines are led into the housing or Lines for liquids and gases (also capillaries). For certain applications are sight glasses in the housing wall provided. In all cases has the housing wall an interruption with a vacuum-tight arranged use.

One Particularly important application of the invention are vacuum systems for mass spectrometers. Preferably, it is about electrical feedthroughs in walls corresponding Vacuum housing. Other applications related to vacuum systems are also included Field of the invention.

Known electrical feedthroughs have a conductive Pin or wire on, which is usually surrounded by a ceramic insulator, which is in a metal part is embedded. The metal part is inserted in the housing wall vacuum-tight. The permanent connection of ceramic and metal parts is complicated and expensive.

task The present invention is to provide a low-cost and also in the assembly efficient solution for a implementation a vacuum housing. In particular, expensive ceramic sealing and insulating material be avoided, as well as a metal part as a carrier.

The inventive vacuum housing has the features of claim 1. Thereafter, the use is multi-part formed, with an insert of a polymer material and a sealing part made of an elastomer material, wherein the sealing part in use held body to Inserts insert. In the body For example, it is a conductive pin or wire, for example made of steel, over an electrical connection between the interior of the vacuum housing and the outside the same is produced. Polymer and elastomer are suitable as vacuum-compatible materials select. In conjunction with electrical conductors, the materials should also electrically isolate, in particular the polymer material. The insert part made of the polymer material is suitably connected to the housing wall connected, such as by screwing or gluing and in conjunction with a sealing ring or other seal. The sealing part guaranteed a vacuum-tight connection between body and polymer material, and even with occurring mechanical stresses, such as through Thermal expansion, production-related shrinkage processes, acting on the body mechanical forces through Connect and release of wires.

in the Insert part can also several bodies, for Example conductive wires or bars be held. Preferably, then each body is a separate seal part assigned, so that arranged in the insert part a plurality of sealing parts are.

To Another idea of the invention is the polymer material injection capable. Accordingly, the insert is made by injection molding. Preferably it is a polycarbonate material. The insert part can be made entirely of polycarbonate by injection molding. polycarbonate has the required tightness (low diffusion) and a low outgassing after injection molding.

To Another aspect of the invention includes the elastomeric material Silicone or a silicone compound. Preferably, the sealing part made of silicone and seals the insert against the body, even with shrinkage after injection molding, with mechanical stresses. silicone adheres very well to many solids, especially steel. By heat and pressure during injection molding also creates an intimate connection between the silicone of the sealing part and the material of the insert.

To Another idea of the invention is that held in use body an electrical conductor, in particular a metallic electrical Ladder. Preferably, it is one or more pins, which are passed with the help of the insert through the housing wall.

According to a further aspect of the invention, the insert is in several parts with a pre-molded part directly on the sealing part and with a molded on the pre-molded part. The injection-molded area preferably completely surrounds the pre-molded part, at least in the direction of the plane of the housing wall. Perpendicular to the housing wall, the pre-molded part can protrude beyond the molded area.

In Further development of the invention is provided that the pre-molded part executed in several parts is with container and lid, being in the container the sealing part is provided. The container in a be prepared first preheating and parallel in time or later the lid.

To In another aspect of the invention, the pre-molded part surrounds the Sealing part completely, at least in the direction or in the plane of the housing wall. If the pre-molded part the sealing part completely surrounds, the body extends, Ladder or the like through both parts - pre-molded part and sealing part - through.

According to the invention is still provided that the insert part has a groove for receiving a ring seal wherein the ring seal seals the insert to the housing wall. Advantageously, the insert is outside the groove with the housing wall firmly connected, in particular screwed.

object The invention is also a highly simplified embodiment of a Vacuum housing with a vacuum-tight interruption of a housing wall. The housing wall or even the case in total can made of a polymer material be prepared, in particular polycarbonate. An additional one Use of polymer material is then not mandatory. Instead is a sealing member made of an elastomeric material in the housing wall arranged and thus seals a passed through the wall body Wall down. The elastomer material extends to or within the housing wall around the body. Preferably If the elastomer material is silicone or one other suitable elastomer.

• a) ein Vorspritzling wird um einen einzubettenden Körper herumgespritzt, derart, dass der Körper beidseitig aus dem Vorspritzling hervorsteht, und derart, dass ein Hohlraum um den Körper herum für ein Dichtungsteil frei bleibt.
• b) das Dichtungsteil wird in den Hohlraum eingebracht,
• c) anschließend wird der Vorspritzling zur Erzielung einer gewünschten Gestalt des Einsatzes umspritzt unter Bildung eines angespritzten Außenteils des Einsatzes.

The method according to the invention for producing an insert for vacuum housings has the following steps:

• a) a preform is sprayed around a body to be embedded, such that the body protrudes from both sides of the preform, and such that a cavity around the body remains free for a sealing part.
• b) the sealing part is introduced into the cavity,
• c) then the preform is overmolded to obtain a desired shape of the insert to form a molded outer part of the insert.

The Production takes place by injection molding. The division of the procedure in the production of the pre-molded part, the introduction of the sealing part and the subsequent one Injection of an outer part has to be beneficial for the tightness and dimensional stability of the insert.

To In another aspect of the invention, the preform is made in several parts executed, namely at least with container and lid. Accordingly, the container is first to the body pre-injected around, then introduced the seal member in the container and then the lid is pre-molded to cover the sealing part. Lid and container are the components of the preform.

• a) ein nach der Herstellung beidseitig aus dem Einsatz hervorstehender Körper wird mit einem Dichtungsteil versehen,
• b) ein Einsatzteil wird im Spritzgussverfahren um das Dichtungsteil herumgeformt.

Another method according to the invention for producing an insert for a vacuum housing has at least the following steps:

• a) a body protruding from the insert on both sides after production is provided with a sealing part,
• b) an insert is molded around the seal member by injection molding.

As already mentioned above, the sealing member is made of an elastomer, preferably made of silicone or another suitable elastomer, such as rubber or acrylic base. The insert consists of an injection-moldable polymer, in particular polycarbonate.

object The invention also provides a mass spectrometer with a vacuum housing in the described Execution.

Further Features of the invention will become apparent from the description of the remainder and from the claims. Advantageous embodiments The invention will be explained below with reference to figures. It demonstrate:

1 A cross section through an insert for a vacuum housing,

2 a cross section through an insert with sight glass,

3 a cross section through an insert with a light guide or a capillary,

4 a cross section through a housing wall with a conductor performed.

In 1 recognizable is an insert 10 for a vacuum enclosure, where the insert 10 the function of a passage through a housing wall (not shown). An electrical conductor is passed through 11 , which is designed here as a steel pin.

The use 10 also has a sealing part 12 and an outdoor part 13 and preform 14 existing insert on. The preform 14 is divided into a container 15 and a lid 16 , being a dividing line 17 between these two parts perpendicular to the ladder 11 runs and preferably about halfway up the sealing part 12 lies.

In the production of the insert 10 The procedure is preferably that first the container 15 as a partial preform with round poured but on both sides protruding head 11 is formed. Subsequently, in a free cavity 18 of the container 15 a sealant consisting of an elastomer as a sealing part 12 brought in. In this case, the sealant or the sealing part 12 over the cavity 18 survive and have approximately a spherical shape. At the same time, the sealant lies sealingly against the conductor 11 on and of course on the container 15 , Subsequently, as the second part pre-molded part of the lid 16 to cover the sealing part 12 formed. This is the sealing part 12 sunk, namely completely enclosed. It can be in the area of the dividing line 17 a tight connection between containers 15 and lid 16 be formed.

Finally, radially outward on container 15 and lid 16 the outer part 13 molded. The latter has an annular groove 19 for a voltage applied to the housing wall ring seal on (not shown). Also, outside the ring groove 19 connecting holes 20 intended.

The electrical conductor 11 is shown here with a smooth, rod-shaped shape. Alternatively, the conductor 11 have on its outside elevations and depressions for tighter connection with the pre-molded part 14 ,

The multi-step production with pre-molded part 14 and outer part 13 ensures a particularly intimate and tight connection of the individual components. Heat and pressure during injection of the outer part 13 ensure a good connection with the pre-molded part 14 , At the same time, the preform will be affected by the high pressure 14 with the filled sealant or the sealing part 12 compressed and thus further improves the tightness. The formation of cracks in this region is effectively prevented, so that no leak path can form.

Basically, the shape of the insert depends 10 from the application. As an alternative to the form shown, the insert may have the geometry of standardized vacuum flanges and connectors, for example in accordance with the standards for small flanges (KF) or according to the CF standard, in particular for components with an ultra-high vacuum. Instead of the annular groove with inserted sealing ring and other sealing means may be provided.

There are also special application-specific forms of use 10 possible, also with clamps or screws fixed forms. Also possible is an assembly with directly cast on the thread in a corresponding counterpart or a clip assembly with clips inside or outside the vacuum housing. The clips or tabs can also be part of the insert directly.

The vacuum housing or a wall thereof may be made in one piece with the insert. Also, several conductors can 11 or body be included in a common use, preferably with its own sealing member per body.

Instead of of an electrical conductor can be others body be provided, such as sight glasses, optical or opto-electronic couplings, glass fibers, mechanical Bushings (for Example rotary joints), Capillaries, etc. The invention is basically usable for all types of bushings, this means to perform of non-plastics in general by urformed plastic parts related to mass, energy or information transport with a vacuum housing. there can the plastic parts are also formed in a different way than by injection molding, for example by extrusion.

2 shows an insert with sight glass 21 in the insert 22 , Fully embedded between sight glass 21 and insert part 22 is the circumferential sealing part 12 , On its underside has the insert 10 a circumferential sealing edge 23 on. The insert lies with the sealing edge 23 on a housing wall, not shown. The sealing edge 23 acts sealingly either by sinking into a softer housing element or by deformation of the relatively narrow sealing edge in contact with a harder housing element. Preferably, the in 2 shown use 10 rotationally symmetrical with a corresponding cylindrical sight glass 21 ,

3 shows a bet 10 as a passage for a light guide or a capillary 24 , Analogous to 1 Here is a preform 14 provided in which the fully embedded sealing part 12 is held and opposite the capillary 24 waterproofing tet. Outside at the pre-molded parts 14 is an outdoor part 13 molded. Preform 14 and outer part 13 form here the insert part. At the bottom of the outdoor unit 13 is an elastic sealing material 25 worked directly around. It may be the same material as the seal part 12 , But also possible is another elastic material.

Finally, concerns 4 a simplified version. A housing wall 26 From a polymer material takes directly the sealing part 12 and the electrical conductor passed therethrough 11 on. The housing wall 26 can together with the passed conductor 11 be made in one operation. Preferably then only the sealing part 11 molded. For this purpose, the housing wall 26 on the outside in the area of the conductor 11 a depression 27 on, in which the sealing part 12 Recording finds. The latter can protrude over the housing wall or only within the trough 27 be provided.

The Invention is preferably usable in the context of mass spectrometers and with high vacuum or ultrahigh vacuum conditions in a vacuum enclosure.

10

commitment

11

electrical ladder

12

sealing part

13

outer part

14

Preform

15

container

16

cover

17

Dividing line

18

cavity

19

ring groove

20

screw

21

sight glass

22

insert

23

sealing edge

24

capillary

25

elastic sealing material

26

Housing wall

27

trough

Claims (14)

Vacuum housing with an insert ( 10 ) in a housing wall, in particular as a passage through an electrical connection, for a mechanical feedthrough, for sight glasses or for other vacuum-tight interruptions of the housing wall, with at least one in use ( 10 ), which extends through the housing wall, wherein the insert ( 10 ) an insert made of a polymer material and a sealing part ( 12 ) made of an elastomeric material, and wherein the sealing part ( 12 ) seals the body to the insert. Vacuum housing according to claim 1, characterized in that the polymer material is injection-moldable. Vacuum housing according to claim 1 or 2, characterized in that the polymer material a polycarbonate material. Vacuum housing according to claim 1 or one of the further claims, characterized that the elastomer material is silicone or a silicone compound includes or is. Vacuum housing according to claim 1 or one of the further claims, characterized in that the in use ( 10 ) held body an electrical conductor ( 11 ), in particular a metallic electrical conductor. Vacuum housing according to claim 1 or one of the further claims, characterized in that the insert part is multi-part, with a pre-molded part ( 14 ) directly on the sealing part ( 12 ) and one on the preform ( 14 ) sprayed area, in particular an outer part ( 13 ). Vacuum housing according to claim 6, characterized in that the pre-molded part ( 14 ) is made in several parts with container ( 15 ) and lid ( 16 ), wherein in the container the sealing part ( 12 ) is provided. Vacuum housing according to claim 6 or 7, characterized in that the pre-molded part ( 14 ) the sealing part ( 12 ) completely surrounds, at least in the direction of the housing wall. Vacuum housing according to claim 1 or one of the further claims, characterized in that the insert part a groove ( 19 ) for receiving a ring seal, wherein the ring seal the insert ( 10 ) seals to the housing wall. Vacuum housing with a vacuum-tight interruption of a housing wall ( 26 ), in particular as an electrical connection, as a mechanical feedthrough, for sight glasses or other interruptions of the housing wall, with at least one body which extends through the housing wall ( 26 ), wherein the housing wall ( 26 ) consists of a polymer material, wherein a sealing part ( 12 ) is disposed of an elastomeric material between the body and the housing wall and seals the body to the housing wall. Method for producing an insert ( 10 ) for vacuum housings, in particular according to one of the preceding claims, with the following steps, a) a preform ( 14 ) is injected around a body to be embedded, such that the body on both sides of the pre-molded part ( 14 ) and such that a cavity ( 18 ) around the body for a sealing part ( 12 ) remains free, b) the sealing part ( 12 ) gets into the cavity ( 18 ), c) then the pre-molded part ( 14 ) to achieve a desired shape of the insert ( 10 ) overmolded to form a molded outer part of the insert. Method according to claim 11, characterized in that the pre-molded part ( 14 ) is executed in several parts, namely at least with container ( 15 ) and lid ( 16 ), and that first the container is pre-injected around the body, that then the sealing part ( 12 ) in the container ( 15 ) is introduced, and that after the lid ( 16 ) for covering the sealing part ( 12 ) is pre-injected. Method for producing an insert ( 10 ) for a vacuum housing, in particular according to one of the preceding claims 1 to 9, with the following steps: a) one after the production on both sides of the insert ( 10 ) projecting body is provided with a sealing part ( 12 b) an insert part is injection-molded around the sealing part ( 12 ) formed around. Mass spectrometer with a vacuum housing after one of the preceding claims 1 to 10.