High Integrity Gate Valve (HIGV) installed
at Hampton Water Treatment Works in London

Hayward Tyler Services, part of the Hayward Tyler Group, recently delivered a new High Integrity Gate Valve (HIGV) to Hampton Water Treatment Works in London.

During the late 1980s and early 1990s Hayward Tyler manufactured and delivered a total of 38-off 1,800mm High Integrity Gate Valves to various Thames Water Utilities Ltd (TWUL) sites for the 80km long London Water Ring Main, of which 31 were installed and one was stored as a spare. The ring main ensures that drinking water is maintained and distributed around London. Along the length of the main are strategically placed 'pump out' shafts and stored water shafts where water is pumped directly into the local distribution systems. It is at these shafts that the HIGVs are located within the main.

In 2006, Hayward Tyler was contacted by several contractors with regard to the possible supply of some new HIGVs for an extension to the existing ring main - Brixton Water Treatment Works to Honor Oak Reservoir and a new pump out shaft at Hampton Water Treatment Works. Hayward Tyler made the valves to the same specifications as the originals, as required by TWUL.
 
Hayward Tyler completed negotiations with the two successful contractors, Black & Veatch (Hampton) and Morgan Est (Brixton/Honor Oak) for the refurbishment of the original spare valve and the supply of four new valves.
 
The refurbished valve was delivered to site in March 2009 with the first 'new build' valve being delivered in May 2009. The remaining valves will be dispatched in Autumn 2009.

Peter Gilman, Project Engineer, Hayward Tyler Services commented: "Working in the Hayward Tyler Heritage Product Team, we are able to react quickly to customer requirements. We can supply like-for-like replacement equipment and spare parts for Hayward Tyler products spanning more than sixty-five years. Our success in securing these contracts demonstrates our continued commitment to customers both here in the UK and worldwide."                       

Hayward Tyler Services provides a variety of outage, repair, overhaul and test services for pumps, compressors, power turbines, gearboxes, motors and other high speed rotating equipment from a wide variety of manufacturers and industries.

For further information, email: marketing@haywardtyler or view website: www.haywardtyler.com  Refer tp page 59

Super precision miniature ball bearings
offer high reliability in surgical hand tools

The latest surgical powered hand tools require miniature, super precision ball bearings, which are not only capable of withstanding the high loads and operating speeds involved, but also to provide high reliability and therefore a longer life of the tool, says Barney Eley of The Barden Corporation (UK) Ltd.
 
The latest handheld cutting and drilling tools used in surgical procedures are now more sophisticated, as well as more compact and ergonomic in their design. But in order to ensure that these tools meet their performance standards and expected life, super precision ball bearings are required, which support the drill or cutting tool during often very harsh operating conditions.
 
The type of power tool - whether electric, air or motor-driven - that is used by doctors today during surgical procedures, will normally require super precision ball bearings, often custom engineered to suit the particular demands of the application.
 
Barney Eley, Product Engineer at Barden describes a typical surgical application example: "In surgical procedures, the operator of the sawing tool will undoubtedly have to put a relatively large load on the ball bearings. Since the tool might be used to saw through bone or to cut through tendons, muscles, cartilage and other bodily tissues, the operating environment for the bearings is very harsh. Typically, the bearings are located close to the end of the cutting tool, often working inside the patient's body and so resistance to acids and other corrosive media is critical."

 "This means the manufacturer of the power tool is going to require a bearing that is both compact enough to fit into the slender design of the tool, but also able to cope with the high loads and relatively high operating speeds [up to 80,000rpm] involved. In addition, the bearings will have to withstand the corrosive, slightly acidic operating environment inside the patient's body," he adds.
 
"When you are designing bearings for surgical tools, there are many ways in which the bearing can be improved to suit the application. For example, we can alter the curvature of the raceways, as well as the height or size of the shoulders. Tighter curvatures within the raceways will lead to a reduction in contact pressure."
 
Another important design consideration for the bearings is resistance to temperature. As surgical tools require regular sterilisation in autoclaves, the bearings must be designed to withstand temperatures up to around 140 deg C. "Most of our bearing designs for surgical cutting tools will be manufactured in corrosion resistant 440C stainless steel, which provides sufficient resistance to cleaning chemicals and other aggressive acidic media," confirms Eley.
 
"The bearings, which we supply as either deep groove or angular contact configurations, are normally provided with phenolic cages to provide further resistance to repeated sterilisation cycles."
 
The harsh operating environment for the bearings also means that protection is required against any fine particles of soft tissue and bone that may penetrate the contact regions between the balls and the bearing raceways, which would then lead to high stress concentrations and could lead to the eventual failure of the bearing.
 
In order to counter these problems, Barden can provide integral shields that are designed to help retain the lubricant (normally a food-grade grease in surgical tool applications) whilst preventing the ingress of contaminants. "This improved sealing design reduces the critical gap between the integral shield and the bearing inner ring to 60 per cent of that when compared to conventional shield and circlip designs. This means you get a reduction in operating noise, greater lubricant retention and improved protection from contaminants - all of which often leads to a longer life of the cutting tool," confirms Eley.
 
In surgical applications, the cleanliness of the bearings is essential. Barden's manufacturing plant in Plymouth has more than 1700 square metres of fully equipped cleanroom facilities, where all assembly, testing and packing operations take place. "On a recent surgical sawing tool project, the bearings we provided were custom engineered angular contact ball bearings with an outside diameter of 4.76mm and contained balls just 0.79mm in diameter, which is the smallest diameter we have provided for this sort of application. Here, our clean room facilities were essential. Handling miniature ball bearings is not a simple task and we have the facilities and personnel here."
 
The bearings provided were of a double row cartridge design with a single inner ring and two outer rings. "This design," says Eley, "enabled us to incorporate an integral, one-piece shield on both sides of the bearing in order to prevent ingress of contaminants and to retain the lubricant. This one-piece, pre-loaded custom designed bearing solution made assembly much easier for the customer, who simply had to 'drop' the bearing into position within the overall tool drive assembly."

For further information, e-mail: caroline.evans@schaeffler.com or view website: www.bardenbearings.co.uk     Refer to page 75

New series of Neo-Flex couplings feature torsional vibration isolation 

A new series of metric Neo-Flex couplings from Advanced Antivibration Components (AAC) feature excellent torsional vibration isolation plus shaft-to-shaft insulation. The center of these couplings, identified as the V50FSR-... (inch) and V50FSRM... (metric) for the Short Series, and V5DFLR-...(inch) and V5DFLRM (metric) for the Long Series, are made from 73 durometer molded neoprene along with 303 stainless steel hubs. They are featured at the AAC eStore where you can order online, request a quote, download CAD models, check stock plus view catalogue and technical pages.

They are stocked in two hub styles; conventional pin type hubs which use a set screw for fastening, and a Fairloc® version. Fairloc® is a patented integral hub fastener which eliminates marred shafts. The choice of Fairloc® hubs permits frequent phase adjustment, timing and position adjustment while adding positive metal-to-metal fastening strength along both hub sections. The Fairloc® integral hub fastener consists of two slots that are machined into the hub, one radially the other angularly, to create a transverse wedge which remains attached to the solid portion of the hub on one side. The resultant cantilevered clamping section has a tapped hole to accept a cap screw which passes through a clearance hole in the solid portion of the hub, and into a threaded hole in the transverse wedge section. As the screw is tightened, the cantilevered section clamps the shaft securely. The screw can be tightened and released repeatedly without marring the shaft or affecting its torque-transmitting abilities.

They are stocked with both ribbed and smooth style center sections. The ribbed style features an angular misalignment of 5° or 15° (long style) and a parallel offset of 0.25 mm (.010")(short style) or 0.38 mm (.015")(long style). The smooth style features an angular misalignment of 1° (short style) or 8° (long style) and a parallel offset of 0.13 mm (.005")(short style) or 0.25mm (.010")(long style). They are designed to fit 3 to 6 mm metric shafts or .1200, 1/8, 3/16 and 1/4 inch shafts.

AAC stocks a wide range of antivibration and shock isolation products which include: stud & nut type mounts, base plate fastened mounts, wheels, leveling & foot mounts, suspension mounts, spring, steel mesh & cable mounts, bumpers, shock absorbers & channel mounts, bushings & grommets, pads & tapes, and couplings. These products are stocked in different materials including: rubber, neoprene, urethane, sorbothane, stainless steel mesh and springs.  Many are suitable for use in extreme environmental conditions. Of special interest is a complete selection of Silicone Gel floor mounts, pads, sheets, plus paste-type thermal gel.
 
Additional technical specifications are contained in Catalogue V100, available free upon request from Advanced Antivibration Components (AAC), 2101 Jericho Turnpike, Box 5416, New Hyde Park, New York, USA 11042-5416. Tel: 516-328-3662.

For further information view website: http://www.vibrationmounts.com/NewProducts/NeoFlexCouplings.htm   Refer to page 99