GB2553322A

GB2553322A - Drive seal

Info

Publication number: GB2553322A
Application number: GB1614815.7A
Authority: GB
Inventors: Michael George Lord Gary
Original assignee: Edwards Ltd
Current assignee: Edwards Ltd
Priority date: 2016-09-01
Filing date: 2016-09-01
Publication date: 2018-03-07
Also published as: CN207634365U; KR20180000720U; DE202017004273U1; GB201614815D0; KR200496383Y1

Abstract

A sealing arrangement 2 comprises a seal carrier 4 and a seal 6 which extends from and is connected to the periphery of the seal carrier. The sealing arrangement is suitable for sealing between a non-planar outer surface portion of a vacuum pump casing (24, fig. 3) and a non-planar inner surface portion of a housing (12, fig. 2). The periphery of the seal carrier is shaped to conform to the non-planar sealing surfaces (44, fig. 2 and 46, fig. 3) of the two components being sealed. The seal carrier may be formed from thermoplastic engineer polymer, and may be injection moulded. The seal may be formed from a thermoplastic polyester elastomer, and may be injection moulded onto the seal carrier. The vacuum pump casing may be a turbomolecular pump (TMP) casing. Having the seal carrier shaped to conform to a complex, three-dimensional surface allows an effective seal to be achieved repeatedly without the need for time consuming manual alignment or the risk of pinching and damaging the seal.

Description

(71) Applicant(s):

Edwards Limited (56) Documents Cited:

EP 0281228 A1 DE 019712109 A1 US 4597583 A1

WO 2001/079730 A2 US 4997193 A1 US 20140138917 A1 (Incorporated in the United Kingdom)

Innovation Drive, BURGESS HILL, West Sussex, RH15 9TW, United Kingdom (58) Field of Search:

INT CL F04D, F16J Other: EPODOC, WPI, TXTA (72) Inventor(s):

Gary Michael George Lord (74) Agent and/or Address for Service:

Edwards Limited

Innovation Drive, BURGESS HILL, West Sussex, RH15 9TW, United Kingdom (54) Title of the Invention: Drive seal

Abstract Title: Sealing arrangement for non-planar surfaces (57) A sealing arrangement 2 comprises a seal carrier 4 and a seal 6 which extends from and is connected to the periphery of the seal carrier. The sealing arrangement is suitable for sealing between a non-planar outer surface portion of a vacuum pump casing (24, fig. 3) and a non-planar inner surface portion of a housing (12, fig. 2). The periphery of the seal carrier is shaped to conform to the non-planar sealing surfaces (44, fig. 2 and 46, fig. 3) of the two components being sealed. The seal carrier may be formed from thermoplastic engineer polymer, and may be injection moulded. The seal may be formed from a thermoplastic polyester elastomer, and may be injection moulded onto the seal carrier. The vacuum pump casing may be a turbomolecular pump (TMP) casing. Having the seal carrier shaped to conform to a complex, three-dimensional surface allows an effective seal to be achieved repeatedly without the need for time consuming manual alignment or the risk of pinching and damaging the seal.

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

- 1 DRIVE SEAL

FIELD OF THE INVENTION

The present invention relates to a sealing arrangement, in particular a sealing arrangement for sealing between a vacuum pump housing and electronic drive housing.

BACKGROUND

Turbomolecular pumps (TMPs) are used in many devices such as mass spectrometers and scanning electron microscopes to achieve the low pressures required for them to operate correctly.

The housing containing the electronic drive required to operate the turbomolecular pump motor and internal electronics can either be located remote from, or directly connected to, the TMP casing. As electronic circuits become smaller, more TMPs are being manufactured with the drive housing connected directly to the TMP casing.

In order to protect the drive electronics contained within the housing from particulate and moisture from the surrounding environment a seal element must be located between the outer surface portion of the turbomolecular pump casing, to which the drive is to be attached, and the inner surface portion of the electronic drive housing to be attached to said outer surface portion of the pump casing.

Presently the seal to protect from the ingress of particulate and moisture is achieved in two ways.

The first method is the use of a sealing foam, which is applied between the pump casing and drive housing when attaching the two elements together. This provides excellent sealing initially, but if the drive housing needs to be removed, for example to service the TMP, the foam residue must be completely removed from the surfaces of the TMP and drive housing before new foam can be re-2applied when reattaching the two elements. In addition if the sealing foam is applied in production it is occasionally known to be damaged in transport forming leak paths into the drive housing.

The second known method is to form a seal groove in the outer TMP casing surface and/or the inner drive housing surface for receiving a seal for sealing between the two elements. However, the location of the seal element into the complex three dimensional, non-planar seal groove is time consuming and requires a high skill level to achieve the correct sealing without pinching, or damaging, the seal. Also, if the drive housing needs to be removed the seal must be relocated in the groove adding considerable time to the process.

SUMMARY

Therefore the present invention provides a sealing arrangement for sealing between a non-planar outer surface portion of a vacuum pump (such as a turbomolecular pump) casing and a non-planar inner surface portion of an housing to be removeably attached to said outer surface portion of the vacuum pump casing, said sealing arrangement comprising a seal carrier and a seal, said seal extending from and connected to a periphery of the seal carrier, said periphery of the seal carrier being shaped to conform to the non-planar shape of the outer surface portion of the vacuum pump casing and the inner surface portion of the housing.

By providing a sealing arrangement with a seal carrier being shaped to conform to the often complex three dimensional, non-planar, surface of both the TMP casing and inner surface of the electronic drive housing an effective seal between the two parts of the pump can be achieved repeatedly without the problems associated with the previous sealing methods.

Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be

-3combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described further, with reference to the accompanying drawings, in which:

Figure 1 illustratively shows a sealing arrangement according the present invention;

Figure 2 illustratively shows a sealing arrangement located against the inner nonplanar surface portion of a drive housing according to an embodiment of the present invention;

Figure 3 illustratively shows the corresponding non-planar surface portion of a turbomolecular pump for receiving the sealing arrangement located against the inner surface portion of a drive housing of figure 2;

DESCRIPTION OF THE EMBODIMENTS

Referring to figures 1 to 3:

The sealing arrangement 2 comprises a seal carrier 4 which is formed, or shaped, at least at its outer peripheral edge, to conform to, or match, both the complex three dimensional, non-planar inner surface portion 44 of a drive housing 12, and the complex three dimensional, non-planar outer surface portion 46 of a turbomolecular pump casing 24.

The sealing arrangement 2 also comprises a seal 6 which extends from, and is connected to, the outer peripheral edge of the carrier 4. Thus, when the sealing arrangement 2 is placed between the pump casing 24 and drive housing 12, the seal 6 is brought into intimate contact with both the casing surface portion 46 and housing surface portion 44 for sealing between the drive housing 12 and pump casing 24. That is, the seal 6 extending from the peripheral edge of the seal carrier 4 co-operates with both the outer casing portion and the inner housing portion to form a seal therebetween.

-4The use of the sealing arrangement 2, comprising the seal carrier 4 and seal 6 according to Claim 1 enables rapid assembly and reliable sealing between a turbomolecular pump and electronic drive housing.

The seal carrier 4 may be formed from any suitable material that is able to substantially maintain the shape of the inner surface portion 44 of the drive housing 12, and the outer surface portion 46 of the turbomolecular pump casing 24, whilst allowing a degree of flexibility to ensure that differences in the tolerance of the carrier itself or the individual devices to which it is to be placed between can be accommodated. For example, a thermoplastic engineer polymer such as polybutylene terephthalate, may be used by injection moulding with a glass filler such that at least its outer edge, or periphery conforms to, or matches, the non-planar shape of the outer surface portion of the turbomolecular pump casing and the inner surface portion of the housing .

The seal 6 may be formed from any suitable sealing material, for example a thermoplastic polyester elastomer which is injection moulded onto the peripheral edge of the seal carrier. The seal may also be a suitable seal material which is fixed to the peripheral edge of the seal carrier with an adhesive, or other suitable connection means, such that it only need be attached to a complex three dimensional carrier shape once allowing rapid removal and replacement of the seal arrangement when servicing the drive or turbomolecular pump.

The seal carrier may also allow a degree of heat transfer from the pump casing to the electronics so that heat can be removed through the carrier from the pump (motor etc) via the electronics cooling circuit. The seal carrier 4 comprises at least one electrical feed-through (8, 10, 48) for allowing cables to be conveyed from the turbomolecular pump motor (not shown) to the electronic drive in the housing 12 through the sealing arrangement 2.

-5The seal arrangement 2 may also be retro-fitted to existing drive housing and TMP casing combinations in place of either the sealing foam or the fitted seal described above.

Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiment and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their io equivalents.

REFERENCE SIGNS 2 - Sealing arrangement 4 - Seal carrier

6 - Seal

- Feed through 10 - Feed through 12 - Drive housing 16 - Fixing location

18- Fixing Location

- Sealing surface 24 - Turbomolecular pump housing 46 - Sealing Surface 48 - Feed Through

66 - Fixing location

Claims

1. A sealing arrangement for sealing between a non-planar outer surface portion of a vacuum pump casing, and a non-planar inner surface portion

5 of an housing to be removeably attached to said outer surface portion of the vacuum pump casing, said sealing arrangement comprising a seal carrier and a seal, said seal extending from and connected to the periphery of the seal carrier, said periphery of the seal carrier being shaped to conform to the non-planar shapes of the outer surface portion of io the vacuum pump casing and the inner surface portion of the housing.

2. A sealing arrangement according to Claim 1, wherein the seal is formed from at least one of a thermoplastic polyester elastomer,

3. A sealing arrangement according to Claim 1 or 2, wherein the seal carrier is formed from thermoplastic engineer polymer.

15

4. A sealing arrangement according to any preceding claim, wherein the seal carrier is an injection moulded seal carrier and the seal is an injection moulding onto the seal carrier.

5. A sealing arrangement according to any preceding claim, wherein the vacuum casing is a turbomolecular pump casing.

20 6. A seal carrier substantially as herein described with reference to the description and/or drawings.

Intellectual

Property

Office

Application No: GB1614815.7 Examiner: Rob Valkass