Dynamic sealing

No oil seals are required and there is no need to empty out the oil from the transformer when discon- necting for routine maintenance and inspection. It also becomes possible to carry out a capacitance check on the connector while it is live on the transformer.

Contact: Permali Gloucester Ltd, Bristol Road, Gloucester GL1 5TT, UK. Tel: + 44 452 528282; Fax: + 44 452 507409.

Undersea cables use el tomer p tection Undersea cables are used in a variety of applications including power, instrumentation and communications. They need to be flexible, insulate the internal compo- nents from seawater, protect against constant move- ment, impact and abrasion and have a working lifespan of about 15 years.

Hydrocable Systems Ltd manufactures underwater and harsh-environment cables. The company uses Bayer Plastics' Desmopan 8600 elastomer to provide its products with a tough, impervious outer sheath.

Hydrocable uses Desmopan because it is processed easily and has a proven long life performance in sheathing, which is essential in view of the conditions presented once the cables sink below the sea's surface.

Hydrocable also makes cable and electrical connec- tor terminations and has just supplied gas monitoring equipment for a major contract in the Far East.

Contact: Bayer plc, Bayer House, St rawberry Hill, Newbury, Berkshire RG13 IJA, UK. Tel: + 44 635 39000; Fax: +44 635 563513.

Hydrocable Systems Ltd, Unit 2A, Woodstde Road, Bridge o f Don, Aberdeen AB2 8EF, Scotland. Tel: +44 224 706611; Fax: +44 224 706006.

I I I I

yrinth als e x t e n d bearing life Industry sources have reported that over 90% of all rolling element bearings will not reach their projected design life. This is due to lubricant contamination originating with dirt, dust, water or airborne vapour condensate.

A large majority of these failures could be prevented through the use of suitably installed bearing housing

seals such as lip seals, non-contacting rotor-stator seals or labyrinth seals.

J M Clipper Corporation has recently introduced the ProTech labyrinth seal. The non-contact design extends bearing life without any leakage.

ProTech is a unitised, two-piece PTFE seal. Benefits of the design include no rubbing contact, and conse- quently no shaft wear or torque, complete exclusion of contaminants, and low friction for high shaft speeds and negligible energy consumption.

The ProTech seal has been laboratory tested for oil leakage, water and dust exclusion and passed all the tests it underwent.

It is available in the UK through the sole distributors, Clough (Croydon) Ltd.

Contact: In the USA: JM C A i ~ Corporat ion, P O Drawer 2340, N a c o # o c h e s , ~ ~ 3 , 2 ~ , USA. Tel: + 1 409 560 8900; Fax: + 1 409 560 ~ .

In the UK: Clough (Croydon) Ltd, 85 Manor ~ , Walltngton, Surrey SM60DH, Tel: + 44 8~ 395 8787; Fax: + 44 81 647 9235.

I I I I I

a of e q u i p m e n t Seven different designs of mechanical face seal from James Walker Britco have been lannched for industrial pumps, compressors, mixers or agitators.

The new seals are designed for compatibility with corrosive, abrasive or viscous fluids, and can be used safely with high-purity media when product contain, ination must be avoided.

James Walker recommends the seals for OEM and retrofit installation where long maintenance-free opera- tion is needed in chemical, petrochemical, food processing, sewage, water treatment and general industrial plants.

Bodies and springs are manufactured in ten alloys including Hastelloy C, stainless steel, bronze and titanium. Seal faces and seats come in 24 combinations of silicon/tungsten carbide, ceramic, metall carbon or PTFE. Other parts are moulded from eight elastomers/ polymers, with DuPont ~ e z p e ~ u o ~ o m e r used for critical applications.

Two of the seven designs are heavy-duty car*d~idge seals, these are factory set for ~ t n s ~ i Another two are external seals for pumps and vessels handling highly corrosive or high.purity media - one has bellows and can be mounted safely on ~ or ceramic shafts. The remaining three are general purpose internal seals to fit inside a pump's stuffing box.

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4 Sealing Technology No. 3