Archive for

Metal Bellows for Critical Industrial Applications

I built my first bellows 35 years ago from leather and wood. My father was a union sheet-metal man and enjoyed building small projects. Metal bellows for industry generally serve a different purpose than that one, even though they function the same. Still….there are metal bellows pumps that work in some very critical applications in industry.

Bellows, in general, enclose and seal the interior of the space yet allow for movement. They provide a hermetic, all-metal, pressure barrier and seal that flexes various directions.

In air ducting for buildings, often the air handling system will vibrate, and in order to avoid transmitting the vibrations to the rest of the system, bellows are used to reduce the vibrations. Metal bellows will often allow for alignment of one end of a plenum or air duct after the system is built. They are highly resistant to cocking as compared to mechanical seals with o-rings.

Sometimes expansion is expected due to changing temperatures, so a bellows is installed to allow for expansion without stressing the joints or connections. That is the most common use; allowing one section of a material handling system to move without causing stress to the mounting brackets. Over time, movement will tear at any strongly fastened joints and holes can develop.

Stress at joints is a major problem with highly engineered structures. Recently a vehicle bridge collapsed in Minnesota, and the cause might just be stress that built up over time and eventually the joints failed. Metal bellows serve to eliminate or reduce stress in various structures in your liquid or air handling systems.

Bellows are considered an expansion joint, and their design is often covered by standards set forth by the Expansion Joint Manufacturers Association. EJMA specifications are standards used to design a proper part that will perform to the specifications called for. This is both for safety and performance reasons. The amount of pressure that the system will contain is part of the system of specs.

There are generally two different methods of producing metal bellows. Some smaller bellows are formed on a machine that mass produces the parts on a large scale.

If you have any gas appliances in your home there is likely a section of formed bellows where the gas attaches to your appliances. This flexible piping contains the gas inside, allows for easy alignment, and most importantly, reduces stress at the connection points.

When containing flammable gasses in your home, reducing long term stress is a critical safety measure. Formed metal bellows are also used in larger applications such as HVAC, and large piping systems.

On the other end there are welded bellows that may need a custom fabrication for each situation. With this method, each piece, called a diaphragm, of the bellows is custom cut and welded into the bellows needed for a particular situation. This can be made from any metal able to be welded, but generally, non-corroding materials are used.

Obviously, this is a much more expensive process and has many applications in medicine, heavy industry, defense, aviation and aerospace.

Metal bellows are manufactured and sold by companies specializing in metal expansion joints and other piping systems. These couplings have proven to be versatile and to satisfy a variety of applications. They allow you to control fluid movement and containment in your system under a wide variety of pressures, thermal expansion and contraction, pulsations, vibration, equipment movement and convoluted routing requirements.

Classes of Steel Used In Fabrication

Steel is one of the most common building components in use thanks to its durability, strength, and ability to be shaped into custom sizes. The process of shaping steel for use in various projects is called steel fabrication. Steel fabricators use highly advanced machines to cut, grind, burn, and weld steel into shapes of all designs and sizes. The type of steel they use depends upon the qualities needed for the job. There are literally hundreds of types of steel that can be manufactured and these are called alloy steels because they are made from a variety of elements, each selected for its mechanical properties. Here are the most common classes of steel.

Tool steel is made to be molded into tools so it must be hard, durable, and resist cracking. It usually has a carbon content under 1.5%, although that can vary among grades. Tool steel is graded for water hardening, cold-working, shock resisting, hot-working, high speed, and special purpose grades. Varying the degree of toughness and hardness can be achieved by adjusting the amount of elements used such as carbon, manganese, molybdenum, and silicon.

Weathering steel is a special type of steel used in construction that doesn’t need to be painted and once it is weathered, it takes on a stable, rusty appearance. It is often used when making large outdoor sculptures and on bridges and shipping containers.

Crucible steel is so named because of the way it is made, in a crucible. Steel fabricators have used this method for thousands of years to make weaponry and other items. It gives sword blades a distinct wood grain pattern.

Spring steel is made with elements that permit it to spring back into shape when it is bent or twisted. This type of steel is usually high in silicon. It is made to manufacture stage swords, lock picks, spring clamps, springs, and antennas, because all these items need to be able to bend and spring back to their original shape.

Carbon steel is high in carbon and low in other elements. Sometimes any steel that is not stainless steel is referred to as carbon steel. When the carbon content is high, steel gets stronger and harder when it is heat treated. This type of metal is used in steel fabrication of automotive parts and the manufacture of high tension wires, knives, and axes.

Stainless steel is an alloy made with a minimum of 11% chromium by mass. This type of steel has many uses since it doesn’t rust, corrode or show water stains. It is used to make cookware, appliances, industrial equipment, surgical instruments, sculptures, and many food storage containers. Stainless steel has natural antibacterial properties and can be sterilized so it is ideal for food and medical applications.

Maraging steel is made so it has superior strength and malleability. The strength comes from elements such as molybdenum, titanium, and cobalt, rather than carbon. Because of its unique properties it is often used to make engine parts, missile skins, and firing pins in automatic weapons.

Thanks to the ability to create steel with specific properties and the capability to shape it into all shapes and sizes, it has become one of the most widely used products in industry and around the home.

Wheel – Oldest and Remarkable Invention of Man

I’ve been thinking of some possible reason on how this civilization came up to this state of technological dependency? What was the past generations’ contribution to this effect? I read books, journals, and many other source of information including the net just to find a simple clue for this. Only one thing I have observed from those records, man never stop in finding solutions how to make life smooth and easy. They invented things, conducted studies and framed theories. And one of their remarkable inventions was the wheel.

The wheel is a big help in our lives. Using carts in simple transportation of goods from one place to another, up to the exploration of oceans and galaxies. This equipment was developed and used as component of complicated machines which enables us to work with speed and accuracy. This was also used by great men and women in the history of kingdoms and empires. Wheel was attached to their armaments, catapults, and chariots for their advantage in conquering lands, and protecting territories from invaders. This invention helped in the progress of the world’s economy, industry, and technology.

The construction and transportation industry will never move forward without the wheel. The construction of high rise commercial and residential buildings, lengthy expressways, bridges, flyovers, and in the excavation of subways and tunnels, wheel is undeniably present. Through the expertise of the operator, the heavy equipments used in these projects safely moves because of the wheel. In transporting agricultural and industrial products, from the rough carts of cave people up to the automobiles of this modern civilization, wheel is always a component. Some are simple in design others are artistically manufactured to enhance beauty and elegance. Scientists, researchers, and inventors don’t stop in developing this thing in order to utilize its full function with convenience and efficacy.

Wheel is also useful for kids in parks and playgrounds. It enables children to interact each other that they could develop good physical built and a wholesome character. it delivers laughter in amusement centers and casinos, sports enthusiasts gain fame and wealth, hobbyists such as a potter finds satisfaction and relief, and house chores over and done with comfort. Our disabled fellowmen who could not walk now can see the beauty of the surroundings.

All that I wrote above are the benefits accounted for the invention of wheel. Not to mention its worse effect when handled with negligence. But, as long as man seek out for easy way of life and search for industrial and technological advancement, wheel will always share a role in our existence.