Gallagher recently released its Expansion Joint Design Guide, now available for download on our site. This design guide takes an in-depth look at elastomeric, metal, and flue duct expansion joints. The excerpt below is a section of our Expansion Joint Design Guide focusing on types of elastomeric joints and types of pipe movement. To download the entire guide, visit our Resources Page, or click on the image to the right.
The basic purpose of an expansion joint is to absorb movement and vibration in a rigid piping system, being built to expand, contract, and adjust without straining or breaking the piping or ducting on either side. They are specially engineered to handle movements due to thermal expansion, vibrations of pumps, and misalignments due to installation tolerances, while also being resistant to the process conditions and the external influences of the application.
Air Sentry® breathers should be an integral part of any proactive maintenance and reliability program. The breathers are designed to replace the breather cap or air filter on gear boxes, hydraulic fluid reservoirs, bulk storage tanks, oil drums, oil-filled transformers, and other fluid reservoirs. Most older style air venting methods provide minimal, if any, contamination control. Air Sentry® breathers provide the first line of defense in contamination control methodology, utilizing patented designs and featuring color indication silica gel and self-cleaning 2-micron filtration.
Why is Contamination Control Important?
There are two important threats to productivity that an Air Sentry breather can protect you from:
Particulates One research group found that greater than 75% of all machine wear related failures were due to particulate contaminants. Frequently the greatest cost of equipment failure is not the component replacement cost, but the labor production downtime. Most particles start off as dirt that becomes airborne, finds its way into lubricant and fuel reservoirs, and is later transported to bearings, bushings, seals, valves, and other machine components. There they become key ingredients in abrasion, erosion, and fatigue failures. The contaminants also cause lubricant degradation, shortening the life of the lubricant and decreasing its ability to lubricate.
Thordon non-metallic bearings have been used in a wide range of industries and various applications such as in pumps, pivot points, screw conveyors, hydro turbine wicket gates, agitators, and flocculator paddle wheels. Thordon Bearings are design to work under the most extreme conditions: abrasive, corrosive, high impact load, high humidity, and infrequent maintenance periods.
With a low inherent coefficient of friction, Thordon bearings typically do not require grease lubrication. This results in reduced maintenance costs and safety issues. Environmental and product contamination concerns associated with grease lubrication are eliminated. Thordon Bearings are homogenous polymers with built-in lubricants. The lubricants, being dispersed through the bearing material, continue to provide low friction through the life of the bearings.
From the outside, an elastomeric expansion joint looks to simply be made out of molded rubber. Part of the reason expansion joints are used in such a wide variety of applications is that the interior construction of a joint can be custom-designed to handle your specific application – materials of construction will depend on size, temperature, application, media, pressure (S.T.A.M.P.).
Layers of Construction
Synthetic or natural rubber forms seamless, leak-proof lining
Extends fully through bore to outer flange edge
Common materials include chlorobutyl, neoprene, natural rubber, EPDM, Viton* and Hypalon*
Body or Carcass
When wrapped or plied, reinforcements provide support and flexibility between tube and cover
Fabric reinforcement: polyester or other suitable fabrics impregnated with specified elastomers
Metal reinforcement: bonded rectangular steel rings [exclusive to Garlock], or continuous strands of wire and round steel body rings
Metal reinforcement rings provide longer service life, extra safety protection, and extra rigidity, allowing higher pressure ratings
An expansion joint can relieve stress in piping systems and prevent flange gaskets from being crushed. But which expansion joint is best for your specific application? Let us first describe the two types of expansion joints:
Rubber — a flexible connector fabricated of natural and/or synthetic elastomers and fabric and, if necessary, internal metallic reinforcements designed to provide stress relief in piping systems due to thermal movements and mechanical vibration.
Metal — a flexible element (bellows) constructed of relatively thin gauge material (generally stainless steel) designed to absorb mechanical and thermal movements expected in service.
Advantages: Metal Expansion Joints
Rubber joints with standard construction and materials have an upper range to 230°F. Most manufacturers, however, can offer special constructions up to 400°F. Metal expansion joints do offer a far greater range, from -420°F to +1800°F. However, working pressures are reduced at elevated temperatures.
Gallagher recently released its Expansion Joint Design Guide, now available for download on our site. This design guide takes an in-depth look at elastomeric, metal, and flue duct expansion joints. The excerpt below is the first section of our Expansion Joint Design Guide, diving into elastomeric expansion joints, and what to consider when selecting which joint is right for your application. To download the entire guide, visit our Resources Page, or click on the image to the right.
What is an Expansion Joint?
An expansion joint is a specially engineered product inserted in a rigid piping system to achieve one or more of the following:
Relieve system strain due to thermal change
Reduce mechanical noise
Compensate for misalignment
Eliminate electrolysis between dissimilar metals (metal expansion joints)
They are built to expand, contract, and adjust without straining or breaking the piping or ducting on either side. Essentially, an expansion joint is meant to protect the piping system from damage.
The GYLON® ONE-UP® diaphragm is the optimal solution for sanitary applications in air-operated diaphragm pumps. Made using Garlock’s exclusive GLYON® PTFE Diaphragm material, and a proprietary EPDM rubber backing, the GYLON® ONE-UP® is made with the same patented rib construction of Garlock’s standard industrial ONE-UP® pump diaphragm.
Light-weight, robust polymer springs are replacing steel coil springs in a range of energy management applications including track tensioners for light-duty mobile equipment such as skid loaders.
With safety as Priority #1, use of polymer springs eliminates a potential source of injury and safeguards workers during equipment assembly and installation. Polymer springs are much safer to install compared to steel coil springs because their lowered stored energy reduces the risk of injury and damage due to uncontrolled release.
Safer. Lower stored energy vs. steel coil spring reduces risk of uncontrolled release
Smaller. For a given spring force, up to 75% reduction in space allows simple fixturing and assembly
Lighter. Up to 90% reduction in weight for a given spring force gives equipment designers more degrees of freedom in weight distribution
Lightweight design has recently become a much more significant trend in the auto industry. Even with small components like seals, a great deal of weight can be saved. From Freudenberg’s standpoint, several forward-looking issues come together in these approaches.
In his office, Dr. Ted Duclos, the CTO of Freudenberg Sealing Technologies, is holding up a palm-sized plastic ring. “I know that it seems very small and insignificant,” he said. “But components like this quickly add up to several kilograms of weight in an engine.” And weight is one of the factors getting special attention from the auto industry – for a range of very different reasons.
Duclos has just returned from the Lightweight Summit in Würzburg, an international gathering of more than 300 experts from industry and research. Specialized lectures, discussion panels and presentations focus on lightweight design in the auto industry and especially in electric mobility. “Lightweight design is a trend,” Duclos said. In the design of classic internal combustion engines because low weight reduces emissions. And for the future of the electric car because reduced weight increases the vehicle’s range. Or to put it another way, lightweight design is one of several trends that are now logically tied to one another.