• Series: Multi-Stud Tensioning Systems (MSTS)

• Series: Multi-Stud Tensioning Systems (MSTS)© 2006 - Tentec Limited

Published: January 2006

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The Segmented Multi Stud Tensioning System (MSTS) is a portable system designed to simultaneously tension all studs on system closures such as steam generator primary and secondary manways, handwheel and valve covers. This state-of-the-art system applies a predictable and accurate preload to all studs simultaneously, thus eliminating the problems normally associated with conventional torque tightening techniques (e.g., uneven gasket preloads resulting in closure leakage, galling, broken fasteners, etc.)

The MSTS enables the installation and removal of system closures to be completed rapidly in high radiation areas. Therefore, its application is also consistent with meeting ALARA objectives.

The PrincipleHydraulic pressure is applied simultaneously to each segmented stud tensioner. All frictional factors connected with conventional bolt tight-ening methods are alleviated since MSTS apply a direct axial force to the bolts which generates a bolt elongation. This elongation/tension is permanently retained by means of the applications hexagon nuts. MSTS have been designed to be as compact as possible, in order to allow adjacent fitment on as many applications as possible.

Multi-Stud Tensioning System MSTS

»Portable hydraulic tensioning systems designed to tension all studs simultaneously on various closures

»Applies predictable pre load to studs eliminating problems associated with torque tightening techniques

»Meets ALARA objectives by minimising time spent in high radiation area’s to remove/install closures

»Lightweight segments manufactured primarily from ARMOLOY- coated high strength steel to provide superior corrosion protection and long life

»Highly reliable hydraulic piston seals can be replaced easily»Pistons have overstroke indicators, high pressure release device»Diverts high pressure fluid away from the operator if the piston stroke is exceeded

»Sleeved hydraulic hoses protect the operator in the event of hose failure

»Lightweight, portable air operated hydraulic control units are available

Features

• Series: Multi-Stud Tensioning Systems (MSTS)

• Series: Multi-Stud Tensioning Systems (MSTS)© 2006 - Tentec Limited

Published: January 2006

Tentec LimitedPlymouth House

Guns LaneWest Bromwich. West Midlands

United Kingdom. B70 9HSInternet: www.tentec.netEmail:sales@tentec.net

Telephone: +44(0)121 524 1990Telefax: +44(0)121 525 1999

Tentec products are subject to continual development and Tentec reserve the right to make changes in the specification and design of there products without prior notice. All rights reserved. Reproduction in whole or in part without the permission of Tentec Limited is prohibited.

Notes.Tentec Mult-Stud Tensioning Systems are built and designed on request. Contact Tentec with application details for a no obligation design and quote.

Indian Point 2SalemBeaver ValleyV C SummerWolfCreekSeabrook San OnofreWaterford 3St LucieMillstoneUlchin 5/6Calvert CliffsOconee – B & W plantArkansaa Nuclear OneAngra Unit 1 - BrazilKori 3 & 4 - KoreaYonggwang 1 & 2 – Korea

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A small selection of some of the Nuclear utility plants that use Tentec Multi-Stud Tensioning Systems.

Conventional Circular PistonsWhen the bolt tensioner designer is limited to just circular pistons a lot of “useful” space in front and at the rear of the stud is left un-used. To compensate for the relatively small hydraulic pressure area the designer is forced to “stack” multiple pressure chambers on top of each other in order to achieve the right amount of pressure area.

Tentec Elliptical PistonsIf this dead space is used then the optimum piston shape is an ellipse. By using this method it is normally possible to achieve enough hydraulic area to avoid multiple stacked pressure chambers and thus produce a far more reliable bolt tensioning tool.

Typical exploded view of a Tentec Multi-Stud Tensioning System. This particular model features elliptical rams

Unused Space

Unused Space

»Reaction Nuts

»Piston Rams

»Seal Kit

»Hydraulic Inlet Connection

»Segment Body

»Bridge

»Nut Rotating Socket

»Lifting Handles

System Features

Profile cut body to reduce weight

Elliptical shaped piston/rams (if necessary)

Rare earth magnets embedded in Nut Rotating

Sockets, for ease of assembly

Single hydraulic inlet connection per segment

Can be designed with variable bolt chambers per

segment to optimize weight

Extremely reliable machine cut polyurethane

seals

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