Sunday, December 3, 2017

AFTEK-EHS Shows Quad Arc Welder at International Workboat Show 2017

AFTEK-EHS booth at Workboat Show with Quad Arc Welder
AFTEK-EHS booth at Workboat Show with Quad Arc Welder.
AFTEK-EHS (a division of Hotfoil-EHS) just finished a very successful exhibit at the International Workboat Show (the show ran from Nov. 29 - Dec. 1). The International Workboat Show is a trade-only conference and expo for commercial vessel owners, operators and builders as well as the vendors and suppliers that serve them. AFTEK-EHS featured of their most unique and popular products, the Quad Arc Welder. 

The Quad Arc Welder is designed for heavy arc welding and engineered for low maintenance in harsh environments. It is simple to operate and reduces space by combining 4 welders in one package. It is protected with thermostatically controlled alarms on both its rectifiers & transformers.  Dimensions are 51" wide x 40" deep x 57" tall. The Quad Arc is a perfect choice for many of the attending vessel builders, owners, and operators.

For more information, contact Hotfoil-EHS by calling 609.588.0900 or by visiting https://www.hotfoiehs.com.

Wednesday, November 29, 2017

Custom Generator Trucks for Mobile Heat Treating

Hotfoil-EHS designs and manufactures custom Generator Trucks for remote heat treating applications. These truck-based, mobile heat treating systems are also know as Mobile Heat Treating Rigs.

Hotfoil-EHS will custom build a generator truck to your specification, with everything you need for a mobile, in-the-field heat treating system. Custom designs include a variety of generator sizes, power consoles, interior workspaces and layouts, air conditioning, and easy access to all electrical components. 

For more information, visit https://www.hotfoilehs.com or call 609.588.0900.

Monday, November 6, 2017

The History of Hotfoil-EHS

Hotfoil-EHS Headquaters in Hamilton, NJ
Hotfoil-EHS Headquarters in Hamilton, NJ
Hotfoil has a long, established history of product innovation and quality.

Since its founding in the United Kingdom in the mid 1960’s, the company has gone through several changes in ownership and management. In 1993, my father, Neville Richards, and I took ownership of Hotfoil, Inc.

AFTek in Chatanooga, TN
AFTek in Chatanooga, TN
  • In 1996, Electric Heating Systems (EHS) was formed to provide equipment to the heat treating industry.
  • In 2007, we recognized the value of producing our own transformers, both for internal needs as well as external sales. Soon after, a welding equipment and transformer manufacturer named AFTek was acquired. AFTek-EHS operates today in Chattanooga, TN.
  • In 2010, HeatandWeld.com was launched as the e-commerce division of Hotfoil and EHS, selling our line of heaters, controls, and heat treating consumables.
  • In 2012, Hotfoil and EHS merged into a new entity appropriately named Hotfoil-EHS, Inc. The merger produced an organization with over 70 employees and an impressive engineering capability.
Hotfoil-EHS in LaPorte, TX
Hotfoil-EHS in LaPorte, TX
Through continued re-investment of profits, Hotfoil-EHS subsequently acquired additional large fabrication facilities and assets, resulting in expansive facilities that include laser cutters, CNC machines, sheet metal breaks, Bridgeport milling machines, rollers and welding machines.

Today, Hotfoil-EHS is a full-service engineering, design, and manufacturing company for any type of industrial heating requirement.

Hotfoil-EHS in LaPorte, TX
Hotfoil-EHS in LaPorte, TX
From what started in 1993 as a humble 800-square-feet facility in a commercial office building, has grown to a total of 68,000-square-feet of manufacturing space located in Hamilton, NJ, Chatanooga, TN, and LaPorte, TX. In 2018, Hotfoil-EHS will open it’s first international location with the launch of a new Birmingham, England facility.

Monday, October 23, 2017

Custom Control Panels - Engineering, Design, Fabrication, Start-up.

Hotfoil-EHS Custom Control Panels
Hotfoil-EHS provides custom design control panels for many industrial applications, with a special expertise in electric heating systems. All Hotfoil-EHS panel designs are deigned with state-of-the-art AutoCAD software and can be tailored for any requirement - from the simplest on/off control requirement, to the most sophisticated PLC controlled, multi-zone configuration.

Driven by a simple common-sense approach Hotfoil-EHS is recognized for high quality and affordability. On-site start-up services are available for all Hotfoil-EHS control panels. All systems are 100% tested prior to leaving the plant. Panels are made in the proudly USA.

Wednesday, October 18, 2017

Plasma Arc Welding: The Basics

Preliminaries: What is an arc? 

Inert gases used in welding, helium and argon, are made up of loose atoms flying around and banging against themselves and the walls of their container. At high temperatures the atoms speed up and negatively charged electrons are knocked off the atoms. A plasma is  a kind of soup of little, fast-moving, negative electrons, neutral atoms, and big, slow-moving, positively charged ions (what's left of an atom after electrons have been knocked off). Plasmas are neutral because the charge of the ions and electrons balance, but because the electrons and the ions can move independently, plasmas conduct electricity like metals. Plasmas can be started by applying a high electric field to a gas. The electric field (volts per distance) picks up a stray electron and slams it into a neutral atom hard enough to knock out more electrons. An electron avalanche takes place and starts a plasma. This happens when an arc is struck. A high frequency current can do it, too.

As plasma cools off, the electrons move more slowly and are recaptured, and the plasma is no more unless the energy loss to its surroundings is replenished. A voltage imposed on a plasma accelerates the conducting charges and can maintain a plasma indefinitely. A welding arc is a plasma maintained between oppositely charged electrodes. In the GTA (gas, Tungsten, arc) process one electrode is a tungsten rod; the other is the workpiece.

The arc column itself is hot, say 10,000 to 20,000 °C. A voltage drop of around one volt per millimeter is typical for an arc column. Thus if the arc is conducting a 100 amp current, about 100 watts of power is needed to maintain a millimeter of arc column, around the same as a light bulb. The really important voltage drops, through which the electrodes are heated, occur at the electrodes. This will be discussed below.

How a PAW Torch Works 

A plasma torch is like a little rocket engine. The plasma is initiated by a high frequency AC voltage in a chamber inside the torch in an inert "plasma gas." As the plasma gas is fed into the chamber it heats up and expands as well as ionizes. The hot gas rushes out through a water-cooled nozzle as a plasma jet.

The plasma jet can be used directly as a heat source, but usually the arc is transferred to the workpiece. The internal "pilot arc" is no longer necessary once the transference takes place. The transferred arc still heats the plasma gas inside the torch and the plasma gas still rushes out as a plasma jet.

Keyholing 

The plasma jet makes a particularly stable arc with less tendency to wander erratically and somewhat greater concentration than a GTAW arc. It is not so sensitive to standoff distance as is a GTAW torch. But especially useful is the ability to operate in the "keyhole" mode.

The plasma jet has kinetic energy that produces a pressure when it impinges against a weld pool. The pressure is enough to push a centimeter or two into a pool of liquid metal, so that a plasma arc can penetrate into the workpiece like an electron beam or a laser, although the penetration mechanism is not the same. Hence plasma arc welds can be deeper and narrower than GTA welds. The number of weld passes can be reduced in changing from GTAW to PAW.

When the PAW process is operated with the arc penetrating all the way through the workpiece the operation is said to be in the "keyholing" mode. The arc impinges on the forward surface of the "keyhole." Melted metal flows around the sides of the keyhole and the streams join behind the keyhole. (The flow of metal is driven by variations in surface tension with temperature, i.e. thermocapillary forces.)

In metals that form tenacious oxides, or sometimes due to contamination in spite of the shield gas used to envelope and protect the keyhole, an oxide layer reminiscent of plastic wrap covers the converging streams of molten metal. A lumpy non-weld results.

But keyholing has a tendency to blow away weld seam contaminants. Where weld seam contamination is a problem PAW in the keyholing mode might be considered. Porosity in aluminum alloys might be reduced in this way. In the latter case special measures need to be taken to avoid problems from the tenacious oxide on the surface of aluminum.

Polarity and Why It Matters 

At the cathode or negative electrode the temperature must be high enough so that the electron emission process keeps the arc supplied. Otherwise the arc goes out. The needed heat is generated when the cooled end of the arc increases in resistance and produces a voltage drop. The heat replenishes the heat conducted away by the electrode metal, the energy required to pull each electron out of the metal, and the energy required to heat each electron to the plasma temperature.

The energy to pull an electron out of a metal is expressed as a voltage drop called the "work function." At the anode or positive electrode the heat that must be supplied to maintain equilibrium is approximately (neglecting thermal radiation effects) the heat conducted away by the electrode metal. Besides heat generated by the higher resistance of a locally cooled plasma, heat is brought to the surface by the amount of the energy gained when an electron enters the electrode metal (work function) and by the greater plasma temperature of the entering electrons.

Because the electrons extract heat from the cathode and deliver heat to the anode, the welding process is considered to be more efficient when operated in "straight polarity," when the torch electrode is negative, the workpiece positive, and electrons flow to the workpiece. Unless there's a reason not to, welding torches are operated in the straight polarity mode.

But there is a reason to weld in "reverse polarity," where the electrons flow away from the workpiece: the cathodic cleaning effect. A high speed movie of the vicinity of a GTA weld pool in the reverse polarity mode will reveal a display of sparkling points of light, miniature explosions continually occurring all over the surface. This is thought to be caused by electrostatic breakdown of a thin surface oxide layer. The positive ions in the arc accumulate on the surface of the oxide layer and induce a balancing negative charge. If the oxide layer is thin, it doesn't take a lot of charge to produce an electric field (volts per distance) big enough to cause the oxide layer to break down in a mini-explosion. Cleaned surface is distinct and visible around the crown of a weld made in reverse polarity.  But to get the cleaning necessary to weld aluminum alloys one takes a hit in power available for welding, and the effective capability of the machine is reduced.

Abstracted from a 2004 NASA document by Arthur Nunes.

Monday, October 9, 2017

Prevent Bulk Material Flash Freezing in Hoppers and Chutes

FRP heating panel
Heaters in stalled on a chute.
A phenomena know as “flash freezing” occurs when aggregate material with trace amounts of absorbed water comes into contact with very cold metal surfaces, resulting in the aggregate instantaneously freezing.  The frozen material then instantly bonds to steel chutes or hoppers (which are at sub-freezing temperatures) causing an immediate, and possibly catastrophic, block in the hopper or chute.

Once this occurs, the cure is often a jack-hammer or other type of brute force method to clear the obstruction It's common for any coal mine, quarry, cement manufacturer, mining facility, or power plant to have a sledge or jack hammer on call for just this purpose. A far better approach is to prevent  sand, cement, ores, and mined products from freezing in the first place. 

The best solution are electric FRP heating panels. FRP heating panels are waterproof, dust tight, and vibration resistant electric heater panels that mount to the exterior walls of the hoppers and chutes. 
Specially designed for use in high shock and high vibration applications, their robust construction and corrosion resistance provides long life. 

FRP heating panel
Multiple heaters on a round hopper.
Because these atmospheres are normally dusty, and occasionally ignitable,  FRP panels are available with FM approval for use in hazardous areas. Furthermore, because hoppers, ducts, and chutes come in a never-ending variety of sizes and shapes, FPR panels are easily customized to conform in shapes and size to virtually application. 

If you work in a plant or facility where bulk material absorbs ambient moisture, and the possibility of freezing exists, you should learn more about FRP heating panels and their benefits they provide in reducing downtime, and more efficient operations. 

Thursday, September 28, 2017

Heat Treatment Controllers

ICE STAR manufactures fully digital heat precise and reliable treatment controllers. The ICE STAR controllers ISQ and ISC have from 6 to 12 controlling thermocouple's and up to 36 monitoring thermocouple's. More measurement points are available by connecting up to 14 controllers to each other wirelessly or with cables. The controllers are designed for any kind of heat treatment consoles and furnaces, and can be mounted inside or to front panel. Hotfoil-EHS is the North America representative for ICE STAR.


For more information, visit https://hotfoilehs/icestar or call 609.588.0900.

Tuesday, September 12, 2017

Common Types of Process Heating Systems and Equipment

Electric Tank Heaters
External Electric Vessel Heater

In all process heating systems, energy is transferred to the material to be treated. Direct heating methods generate heat within the material (e.g., microwave, induction, or controlled exothermic reaction), whereas indirect methods transfer energy from a heat source to the material by conduction, convection, radiation, or a combination of these functions. In most processes, an enclosure is needed to isolate the heating process and the environment from each other. Functions of the enclosure include, but are not restricted to, the containment of radiation (e.g., microwave or infrared), the confinement of combustion gases and volatiles, the containment of the material itself, the control of the atmosphere surrounding the material, and combinations thereof.

Common industrial process heating systems fall in one of the following categories:
Large Heat Treated Parts
Large heat treated parts - still red-hot.
  • Fuel-based process heating systems 
  • Electric-based process heating systems 
  • Steam-based process heating systems 
  • Other process heating systems, including heat recovery, heat exchange systems, and fluid heating systems. 
The choice of the energy source depends on the availability, cost, and efficiency; and, in direct heating systems, the compatibility of the exhaust gases with the material to be heated. Hybrid systems use a combination of process heat systems by using different energy sources, or different heating methods with the same energy source.

Hotfoil-EHS are skilled experts in a wide variety of process heating systems design and fabrication. Contact them at 609-588-0900 or visit their website at http://www.hotfoilehs.com.

Friday, September 8, 2017

Large, Custom Heat Treat Furnace Fabrication

The video below demonstrates the erection of a 16' x 16' x 62' heat treat furnace built out of a 6x6 I-Beam skeletal structure with 11 gauge steel skin. Full size doors, two per end, will allow the furnace to heat loads using it's full volume. The furnace is equipped with eight 3-Million BTU burners, one at either end and 3 down each side, to circulate the air. Four dampers are included, two at each end. It will move back and forth on a rail system by (16) 10" crane wheels. A hydraulic system will act to lift the furnace 3" in the air off the hearth. This will allow the furnace to move freely and without damaging the insulation on the bottom seals. It will be controlled via a remote HMI screen with full SCADA capabilities.

For more information, visit http://www.hotfoilehs.com or call 609.588.0900.

Thursday, August 31, 2017

Custom Mobile Heat Treating Trucks

Hotfoil-EHS designs and manufactures custom mobile rigs for remote heat treatment applications.

Custom designs include a variety of generator sizes, power consoles, interior workspaces and layouts, air conditioning, and easy access to all electrical components. For more information, visit http://www.hotfoilehs.com or call 609-588-0900.

Wednesday, August 23, 2017

Basics of Heat Treating

Heat treating furnace
Interior view of heat treating furnace.
Heat treating refers to the heating and cooling operations performed on metal work-pieces to change their mechanical properties, their metallurgical structure, or their residual stress state.

Heat treating includes stress-relief treating, normalizing, annealing, austenitizing, hardening, quenching, tempering, martempering, austempering, and cold treating. Annealing, as an example, involves heating a metallic material to, and holding it at, a suitable temperature, followed by furnace cooling at an appropriate rate. Steel castings may be annealed to facilitate cold working or machining, to improve mechanical or electrical properties, or to promote dimensional stability.  Steel vessels, girders, pipes, and structures are heat treated prior to, and after welding to improve weld quality and strength.

Gas fired furnace used for heat treating.
Gas fired furnace used for heat treating.
Heat treating is performed in conventional furnaces, salt baths, or fluidized-bed furnaces. The basic conventional furnace consists of an insulated chamber with an external reinforced steel shell, a heating system for the chamber, and one or more access doors to the heated chamber.

Heating systems are direct fired or indirect heated. With direct-fired furnace equipment, work being processed is directly exposed to the products of combustion, generally referred to as flue products. Gas- and oil-fired furnaces are the most common types of heat treating equipment. Indirect heating is performed in electrically heated furnaces and radiant-tube-heated furnaces with gas-fired tubes, oil-fired tubes, or electrically heated tubes.

Wednesday, August 16, 2017

Industrial Process Heating: Electric and Fuel Based

Electric heater used on industrial hopper throat.
Electric heater used on industrial hopper throat.
Process heating operations supply thermal energy to transform materials like metal, plastic, rubber, limestone (cement), glass, ceramics, and biomass into a wide variety of industrial and consumer products. Industrial heating processes include drying, heat treating, curing and forming, calcining, smelting, and other operations. Examples of process heating systems include furnaces, ovens, dryers, heaters, and kilns. Many of these systems are mature technologies used ubiquitously throughout manufacturing. Process heating is used to raise or maintain the temperature of substances involved in the manufacturing process, such as the use of heat to melt scrap in electric arc furnaces to make steel, to separate components of crude oil in petroleum refining, to dry paint in automobile manufacturing, or to process food for packaging.

Electricity-based process heating systems transform materials through direct and indirect processes. For example, electric current is applied directly to suitable materials to achieve direct resistance heating; alternatively, high-frequency energy can be inductively coupled to suitable materials to achieve indirect heating. Electricity-based process heating systems are used for heating, drying, curing, melting, and forming. Examples of electricity-based process heating technologies include electric arc furnace technology, infrared radiation, induction heating, radio frequency drying, laser heating, and microwave processing.

Gas burners for process heating
Gas burners for process heating.
Fuel-based process heating systems generate heat by combusting solid, liquid, or gaseous fuels, then transferring the heat directly or indirectly to the material. Hot combustion gases are either placed in direct contact with the material (i.e., direct heating via convection) or routed through radiant burner tubes or panels that rely on radiant heat transfer to keep the gases separate from the material (i.e., indirect heating). Examples of fuel-based process heating equipment include furnaces, ovens, kilns, melters, and high-temperature generators.

For information on any industrial heating application, contact Hotfoil-EHS at 609.588.0900 or visit http://www.hotfoilehs.com.

Sunday, August 13, 2017

Pyrometers: Non-contact Temperature Measurement

Red-hot metallic parts from furnace
Pyrometers come in handy for applications
such as heat treating.
Non-contact temperature measurement technology allows process operators and technicians to evaluate the temperature of process materials, machinery, or piping by measuring their electromagnetic radiation. Through inferential calculation and one or more radiation measurements, specialized instruments can determine temperature without contacting the subject material or surface. While the concept of non-contact measurement technology has existed for many years, more recent advancements in non-contact temperature sensing and the evolution of the pyrometer have allowed temperature measurement at a distance to become popular throughout industrial process operations.

Pyrometers can commonly concentrate light from an object onto a temperature sensing element. The sensed elevation in temperature is proportional to the infrared optical energy. Different instruments may have varying arrangements of concentrating lenses and sensors, but the operating principle is the same. The physical law behind the pyrometer's operating principle operates on an exponential mathematical basis that is non-linear. This results in one of the limitations of the pyrometer. A single pyrometer can only, with high accuracy, deliver a comparatively narrow range of target temperature. If the need for accuracy is reduced, the applicable temperature range widens. Innovative manufacturers have developed instruments with technology and features overcoming many of the limitations imposed by the physics, delivering instruments with accuracy and applicable temperature range usable in a wide array of applications.

One of the advantages to using a non-contact pyrometer is that their calibration is independent of the distance between the sensor and the object being evaluated. This phenomenon is due to the fact pyrometers have a field of view and can be filled with the target object in a way independent of distance. While the radiation emanating from the target object may be decreasing, the field of view of the pyrometer is measuring a greater portion of the object which is proportional to the amount of radiation being lost, essentially canceling out the distance and allowing the pyrometer to provide useful output. An example of a practical application of a pyrometer in industry would be its use to check the temperature of a ventilation system in the HVAC field.

Share your temperature measurement requirements and challenges with process instrumentation specialists. Their product application expertise will combine with your own process knowledge and experience to produce an effective solution.

Tuesday, July 25, 2017

Electric Process Heaters & Controls

Hotfoil specializes in electric surface heating systems for fly ash hoppers on electrostatic precipitators or baghouses, coal and material handling systems, tanks, pipes, etc. in all types of industry.

For more information, visit http://www.hotfoilehs.com or call 609.588.0900.

Friday, July 21, 2017

Fuel Based Furnace Types and Applications

Large furnace
Large furnace in production (Hotfoil-EHS)
With fuel-based systems, heat is generated by the combustion of solid, liquid, or gaseous fuel, and transferred either directly or indirectly to the material. The combustion gases can be either in contact with the material (direct heating), or be con ned and thus be separated from the material (indirect heating, e.g., radiant burner tube, retort, muffle). Examples of fuel-based process heating equipment include furnaces, ovens, kilns, lehrs, and melters.

Fuel-based process heating systems are common in nearly every industry segment, and include furnaces like ovens, heaters, kilns, and melters, but also the surface treatment in ambient air. Typical fuel-based furnaces include the following:

  • Atmosphere generators. Used to prepare and/or condition protective atmospheres. Processes include the manufacture of endothermic gas used primarily to protect steel and iron during processing, and exothermic gas used to protect metals, but also to purge oxygen or volatile gases from con ned areas.
  • Blast furnaces. Furnaces that burn solid fuel with a blast of air, often used to smelt ore.
  • Crucible furnaces. A furnace in which the heated materials are held in a refractory vessel for processes such as melting or calcining.
  • Dryer. A device that removes free water, or other volatile components, from materials through direct or indirect heating. Dryers can be grouped into several categories based on factors such as continuous versus batch operation, type of material handling system, or source of heat generation.
  • Indirect process heaters. Used to indirectly heat a variety of materials by remotely heating and circulating a heat transfer uid.
  • Kilns. A furnace used to bake, dry, and re ceramic ware or wood. Kilns are also used for
    Heat treating furnace (Hotfoil-EHS)
    calcining ores.
  • Lehrs. An enclosed oven or furnace used for annealing, or other forms of heat treatment, particularly in glass manufacturing. Lehrs may be the open type (in which the flame comes in contact with the ware), or the muffle type.
  • Muffle furnaces. A furnace in which heat is applied to the outside of a refractory chamber or another enclosure containing the heated material that is enveloped by the hot gases. The heat must reach the charge by flowing through the walls of the container.
  • Ovens. A furnace-like chamber in which substances are heated for purposes, such as baking, annealing, curing, and drying. Heated systems can use forced convection or infrared.
  • Radiant-tube heat-treating furnaces. Used for processing iron, steel, and aluminum under a controlled atmosphere. The flame is contained within tubes that radiate heat to the work. Processes include carburizing, hardening, carbo-nitriding, and austempering. The atmosphere may be inert, reducing, or oxidizing.
  • Reverberatory furnaces. Furnaces in which open flames heat the upper portion of a chamber (crown). Heat is transferred to the material mainly by radiation ( flame, reflection of the flame by the crown) and convection (combustion gases).
  • Salt bath furnaces. Metal pot furnaces filled with molten salt where heat is applied to the outside of the pot or inside of the pot by radiant tube. Salt bath furnaces are used for processes such as heat treating metals and curing plastics and rubber.
  • Solid waste incinerators. Used to dispose of solid waste material through burning.
  • Thermal oxidizers. Used to oxidize volatile organic compounds (VOC) in various industrial waste streams. Processes include paint and polymer curing and/or drying.

Wednesday, July 12, 2017

Induction Heating Basics

Induction Heating
Induction heating coils
around large pipe for
pre-weld heat treatment.
Induction heating occurs when passing alternating magnetic fields through conductive materials. This is accomplished by placing an alternating current carrying coil around or in close proximity to the materials. The alternating fields generate eddy currents in the materials. These currents interact with the resistance of the material to produce heat. There is a secondary heating process called hysteresis. This disappears at the temperature at which the material loses its magnetic properties.

Direct Induction
Direct induction heating occurs when the material to be heated is in the direct alternating magnetic field. The frequency of the electromagnetic field and the electric properties of the material determine the penetration depth of the field, thus enabling the localized, near-surface heating of the material. 

Comparably high power densities and high heating rates can be achieved. Direct induction heating is primarily used in the metals industry for melting, heating, and heat treatment (hardening, tempering, and annealing).

Indirect Induction
With indirect induction heating, a strong electromagnetic field generated by a water- cooled coil induces an eddy current into an electrically conducting material (susceptor), which is in contact with the material to be treated. Indirect induction heating is often used to melt optical glasses in platinum crucibles, to sinter ceramic powders in graphite crucibles, and to melt materials in crucibles prior to drawing crystals. Indirect induction is also used to heat susceptors used for joining operations.


Friday, June 30, 2017

Happy Fourth of July from HotfoilEHS

"We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness. — That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, — That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness."

THOMAS JEFFERSON, Declaration of Independence

Tuesday, June 27, 2017

Quick Facts About Welding as a Profession


Welding is the most common way of permanently joining metal parts. In this process, heat is applied to metal pieces, melting and fusing them to form a permanent bond. Because of its strength, welding is used in shipbuilding, automobile manufacturing and repair, aerospace applications, and thousands of other manufacturing activities. Welding also is used to join steel beams in the construction of buildings, bridges, and other structures and to join pipes in pipelines, power plants, and refineries.

Welders work in a wide variety of industries, from car racing to manufacturing. The work that welders do and the equipment they use vary with the industry. Arc welding, the most common type of welding today, uses electrical currents to create heat and bond metals together—but there are more than 100 different processes that a welder can use. The type of weld normally is determined by the types of metals being joined and the conditions under which the welding is to take place.

Welders, cutters, solderers, and brazers typically do the following:
  • Study blueprints, sketches, or specifications
  • Calculate dimensions to be welded
  • Inspect structures or materials to be welded
  • Ignite torches or start power supplies
  • Monitor the welding process to avoid overheating
  • Maintain equipment and machinery
PAY

The median annual wage for welders, cutters, solderers, and brazers was $39,390 in May 2016. The median wage is the wage at which half the workers in an occupation earned more than that amount and half earned less. The lowest 10 percent earned less than $26,800, and the highest 10 percent earned more than $62,100.

In May 2016, the median annual wages for welders, cutters, solderers, and brazers in the top industries in which they worked were as follows:
  • Specialty trade contractors - $42,900
  • Repair and maintenance - $39,340
  • Manufacturing - $38,200
  • Merchant wholesalers, durable goods - $37,790
Wages for welders, cutters, solderers, and brazers vary with the worker’s experience and skill level, the industry, and the size of the company.

Most welders, cutters, solderers, and brazers work full time, and overtime is common. Many manufacturing firms have two or three 8- to 12-hour shifts each day, allowing the firm to continue production around the clock if needed. As a result, welders, cutters, solderers, and brazers may work evenings and weekends.

Friday, June 23, 2017

Process Heating: Induction

Induction Heater
Induction heating coils around large pipe
in preparation of welding.
The principles of induction heating have been applied to manufacturing operations since the 1930s, when the first channel-type induction furnaces were introduced for metals melting operations. Soon afterward, coreless induction furnaces were developed for melting, superheating, and holding. In the 1940s, the technology was also used to harden metal engine parts. More recently, an emphasis on improved quality control has led to increased use of induction technology in the ferrous and nonferrous metals industries.

In a basic induction heating setup, a solid state power supply sends an alternating current (AC) through a copper coil, and the part to be heated is placed inside the coil. When a metal part is placed within the coil and enters the magnetic eld, circulating eddy currents are induced within the part. These currents ow against the electrical resistivity of the metal, generating precise and localized heat without any direct contact between the part and the coil. 

An induction furnace induces an electric current in the material to be melted, creating eddy currents which dissipate energy and produce heat. The current is induced by surrounding the material with a wire coil carrying an electric current. When the material begins to melt, electromagnetic forces agitate and mix it. Mixing and melting rates can be controlled by varying the frequency and power of the current in the wire coil. Coreless furnaces have a refractory crucible surrounded by a water-cooled AC current coil. Coreless induction furnaces are used primarily for remelting in foundry operations and for vacuum refining of specialty metals.

Induction heating power console
Induction heating power console (Hotfoil-EHS)
Channel furnaces have a primary coil wound on a core. The secondary side of the core is in the furnace interior, surrounded by a molten metal loop. Channel furnaces are usually holding furnaces for nonferrous metals melting, combined with a fuel- red cupola, arc, or coreless induction furnace, although they are also used for melting as well.

The efficiency of an induction heating system for a specific application depends on several factors: the characteristics of the part itself, the design of the induction coil, the capacity of the power supply, and the degree of temperature change required for the application.

Induction heating works directly with conductive materials only, typically metals. Plastics and other nonconductive materials often can be heated indirectly by first heating a conductive metal medium that transfers heat to the nonconductive material.

With conductive materials, about 80% of the heating effect occurs on the surface or “skin” of the part. The heating intensity diminishes as the distance from the surface increases, so small or thin parts generally heat more quickly than large thick parts, especially if the larger parts need to be heated all the way through.

Induction heating can also be used to heat liquids in vessels and pipelines, primarily in the petrochemical industry. Induction heating involves no contact between the material being heating and the heat source, which is important for some operations. This lack of contact facilitates automation of the manufacturing processes. Other examples include heat treating, curing of coatings, and drying.

Induction heating often is used where repetitive operations are performed. Once an induction system is calibrated for a part, work pieces can be loaded and unloaded automatically. Induction systems are often used in applications where only a small selected part of a work piece needs to be heated. Because induction systems are clean and release no emissions, sometimes a part can be hardened on an assembly line without having to go to a remote heat treating operation.

Friday, June 9, 2017

Hotfoil-EHS Attending the 2017 Global Petroleum Show in Calgary

Hotfoil-EHS is pleased to announce our products will be on display at the Global Petroleum Show on June 13 through 15, 2017 at the Stampede Park in Calgary, Canada.

Hofoil-EHS will in exhibiting as a guest of Stein Industries in London, Ontario. Stein will be exhibiting its high quality, custom designed, affordable induction heaters built to withstand harsh environments with wide applications.

This is a great opportunity to see major welding equipment vendors and new technologies being introduced. If you plan on being at the Global Petroleum Show, please stop by the Stein Industries at booth 4404.

The Global Petroleum Show provides direct access to the entire supply chain, innovative technologies, products & services and a massive number of educational seminars within the energy sector. Global Petroleum Show is an industry leading event, where more than 50,000 energy professionals from more than 90 countries converge for three days to strengthen business relationships, network, and do business with more than 1,000 exhibitors. During this pivotal, evolutionary period for the oil & gas sector, it’s never been more vital to re-connect with your global industry. From upstream to downstream, GPS provides a forum where business gets done.

Wednesday, May 31, 2017

Resistor Controlled Welding Machines

resistor controlled welding machines
Resistor controlled welding machines by AFTEK.
Resistor control has been used in multi-operating welding systems in shipyards and heavy construction for decades. In the heyday of nuclear power plant construction in the USA, nearly all were built using multiple-operator systems. From the thirties until about 1990, nearly all multiple-operator systems were the designed similarly. They used a large bulk power supply with “grids” connected by cables to form a system of distributed power. This system minimized the use of high voltage primary power, distributing 75-80 volts of secondary voltage instead.

As these systems grew in popularity, the concept of “packs” became popular. These packs provided 2, 4, 8, and 16 arcs in a steel rack, and all being connected to a separate power supply. A now defunct company named Big Four developed the concept of connecting multiple-operator systems in a loop arrangement, which resulted in greatly improved voltage stability. In 1990, this loop concept was further refined into integrated, modular welding packages. These newly designed systems provided an internal power supply sufficiently sized to provide power to all the arcs without any interference.

Loop systems are still being used today. They are viewed as a very economical welding alternative. For example, for a loop that needs twenty MIG arcs, it is possible to use (4) 500-amp power supplies connected to a single 500 MCM cable which circles the work space. Twenty control modules can be connected wherever needed on the closed loop of cable. A huge cost savings is realized in having to establish just four (4) primary connections instead of twenty (20).

Most conventional arc weld­ers use a transformer-like device called a reactor to control the "heat" of the welding arc. If you examine the Voltage/Amperage (V/A) curve for a con­ventional constant current (or constant voltage) welding power supply, you’ll see spikes. This is inherent in the design of conventional arc weld­ers. The V/A curve of a resistor controlled arc welder, on the other hand, is a straight line.

Resistor controlled arc systems provide more consistency of power - if you shorten the arc, thus lowering the arc voltage, the current will increase, and maintain virtually the same power (heat). If you lengthen the arc, you raise the voltage, but the power remains virtually constant. Why is this important? In any welding process, increasing the amperage increases penetration and increasing the voltage widens and flattens the head (and reduces penetration). With a resistor controlled arc, if you are welding along the seam and it closes, shortening the arc length will increase penetration. If the weld opens, lengthening the arc will lessen the penetration and widen the weld. This provides excellent control right in the electrode holder.

AFTek, a US manufacturer located in Chattanooga, TN and division of Hotfoil-EHS, is the sole remaining manufacturer of resistor controlled welding machines in the USA. Their resistance welders are an acknowledgement of the superior design Big Four developed years ago, while improving performance with edge-wound coils for better heat dissipation (thus better current control) and rotary switches for current selection, even under load.

Wednesday, May 10, 2017

New Product: The ISG Wireless Heat Treatment Controller

ISG heat treat controller
The ISG heat treat controller.
The ISG heat treatment controller is a panel-mounted controller which can easily be connected to thyristor, electrical contactor, or induction/inverter driven power sources. The controller has 2 analog outputs, 5 digital outputs, 2 analog inputs and 2 digital inputs.

The ISG is capable of controlling two measurement points and monitoring two measurement points. If more measuring points are required, up to 14 controllers can be daisy-chained to the same heating process via cables or wireless, while all being managed from a single computer. The ISG communicates with PC's via Zigbee radio or with an RS485 Serial port.

All routines or process plans are created with ISPort software. After the process is started, the routine and the process data is saved to the PC, and also to the controller's memory. This enables the controller to work independently should the connection between ISG and computer be lost. The ISG includes a convenient LED process display and additional process status and alarm LED's.

For more information on the ISG heat treatment controller, visit http://www.hotfoilehs.com or call 609.588.0900.

Wednesday, May 3, 2017

Custom Built Heat Treat Furnaces

Custom Built Heat Treat Furnaces
 15'x15'x60' Custom Furnaces
Hotfoil-EHS has extensive heat treating furnace design and fabrication experience. From small, low-throughput furnaces, to much larger high yield furnaces, to rail-driven furnaces, Hotfoil-EHS Design Engineers and Fabrication Shop have done it all.


 Heat Treat Furnace
Capable of handling 45,000 lbs.
Recently Hotfoil-EHS provided a customer with a heat treat furnace that is 15'x15'x60' that accommodates up to 45,000 pounds of material. Two, 5 million BTU burners heat the furnace to 1650 deg. F. The furnace travels on a track, back and forth, to accommodate two beds for greater production.

 Heat Treat Furnace
Rail system with (2) beds


For more information, visit http://www.hotfoilehs.com or call 609.588.0900.




Sunday, April 16, 2017

A Better Choice in Heat Treatment Control Systems

ICE Star Heat Treatment Controllers
Ice Star, a Finnish company, engineers and manufactures heat treatment controllers for electric and gas furnaces, as well as for induction and resistive heating consoles. The company manufactures the most advanced metal heat treatment control system available today. Since 1984, they have been laser-focused on the development and advancement of industrial heat treatment controllers and software.

ICE Star Model ISG Heat Treatment Controllers
ICE Star
Model ISG
Heat Treatment Controller
Ice Star’s founder, Esa Santala, has decades of knowledge and experience in the heat treatment industry. He developed one of the first processor controlled multi-channel controllers and has since been building even more innovative products.

Ice Star controllers do not require a separate recorder. Ice Star controllers monitor all critical heat treatment variables - temperature, time, soak, upsets, diagrams, events, alarms etc. - and then provide extremely detailed records for each. Additionally, with ISPort software, you can monitor and control the heating processes directly from remote process displays and computers.

For more information about Ice Star in North America, visit Hotfoil-EHS or call 609.588.0900.

Sunday, April 9, 2017

Hazardous Area Heater Control Systems for Coal Hoppers and Conveyors

Explosion proof control system
Explosion proof control system.
A major hazard in coal burning utilities is the transfer and storage of coal due to the presence of highly combustible coal dust. Mitigating the risks of combustible dusts eliminate the potential for dust explosions. It is critically important that any coal handling or coal storage facility have access to experienced application engineers who understand the specific requirements when handling coal and managing coal dust.

Electric heat is very often used to prevent coal freeze-ups in hoppers and conveyors. The most common electric heaters used are are exterior mounted panel heaters with carefully calculated watt densities to keep sheath temperatures low. A less preferred solution is the use of tubular heating elements that may have higher sheath temperatures. Tubular heaters are usually clamped or stud-welded to the exterior of the coal hopper or conveyor chute.  In either case, a control system must be employed to maintain operating temperatures and to safely limit temperatures below dust ignition temperatures.  Since the presence of coal dust in the atmosphere is considered normal, the use of explosion proof housings, conduit, and wiring practices is required for these control systems.

Explosion proof control system
Internal view.
Hotfoil, a New Jersey manufacturer of electric hopper and coal handling heating systems,  designs, engineers, and fabricates custom control systems specifically for these applications. 

With decades of experience in hopper, conveyor, and tank heating systems they provide their customers with a single-source, turn-key, electrical heating and control system solutions provider. All products are 100% quality tested prior to leaving the facility, and an added plus is that they provide on-site start-up assistance.

Thursday, March 30, 2017

Electric Heating and Control Solutions for Power Generation

Hotfoil-EHS specializes in electric surface heating systems in power plants for fly ash hoppers on electrostatic precipitators or baghouses, coal and material handling systems, tanks, and pipes.

For more information, visit http://www.hotfoilehs.com.

Tuesday, March 28, 2017

Weld Heat Treatment is Critical to Structure Integrity

Welding pre-heat
Welding pre-heat is critical to the quality of the weld and
and the integrity of the structure.
In any large scale welding operation (such as pipeline welding, shipbuilding, boiler fabrication) heat treatment is critical to the quality of a weld, and therefore critical to the performance of a structure, and never should not be taken lightly.

When in doubt, review of industry code or a consultation with a welding expert is imperative. Welding code is the first determinant to whether pre-heating is needed. Welding code carefully specifies the minimum preheat temperature, the soak time, and the welding process. Many criteria are considered by welding codes, all gathered from years of rigorously tested data. This data is accumulated from many sources, including metallurgical science, chemical properties of materials, and radiographic analysis.

In its simplest form, weld heat treatment is the process of heating the base metal (parts to be welded) to a desired temperature prior to welding, and then allowing it to cool at a given rate under controlled conditions. The specific temperature to which the part needs to be heated (before welding) is referred to as the “preheat temperature”.

There are several key reasons why it's important to preheat before welding. 
  • A preheated part cools more slowly, which slows the overall cooling rate of the welded part. This improves the metallurgical (crystalline) structure and makes it less prone to cracking. 
  • Hydrogen that may be present immediately after a weld is also released more efficiently, which further reduces the possibility cracking. Preheating also mitigates stress from the shrinkage at the weld joint and nearby metal. 
  • Pre-heating reduces the possibility of fracture during fabrication due to brittleness.
Electric welding preheaters, known as "ceramic mat heaters", are rugged and flexible heating elements designed so that they conform uniformly around the weld and surrounding area.  Ceramic mat heaters are normally controlled by a power console that uses thermocouples and electronic controllers to regulate, monitor, and many times record, the preheat temperature profile.

Another less preferred method to heat the target piece is with a torch, or open flame, but this method carries safety concerns as well as controllability issues. Furnaces are also used, but these typically require the transport of the target piece off-site.

Induction heaters offer an attractive alternative for safety, portability and controllability. Induction heating is unique because it uses molecular excitation as its source of heat, as opposed to open flames or external electric elements. Induction heating works very quickly, and since there is no contact with the target piece, there are far less concerns about part contamination.  Many industrial processes use induction heating when very high temperatures and uniform control is desired.

Each welding application has it's own unique set of circumstances which dictate the optimal heat treating method.  It is always best to contact an expert and solicit their opinion on your best available option.

Friday, March 17, 2017

Welding Heat Treatment Power Consoles

Welding Heat Treatment Power Consoles
Welding Heat Treatment Power Consoles by Hotfoil-EHS
When it comes to Hotfoil-EHS power consoles, there's no cutting corners. By using thicker gauge sheet metal and tubing, top quality electrical components, and quality craftsmanship, Hotfoil-EHS power consoles provide years of reliable and trouble-free service.

Power consoles are standardly offered in 6, 9, 12, 18, and 24 zone configurations with a variety of control and recording systems. All Hotfoil-EHS power consoles are available in Stainless Steel and can be customize to your requirements.

Have a special requirement? Just ask. Need a special color, coating or controls? Hotfoil-EHS is eager to provide a custom power console to meet your exact needs.

Temperature recorders are available for applications requiring documentation and certification. Fully automatic controllers are provided when specific heat-up and cool-down profiles are needed.

EHS manufactures and sells accessories including:
  • ceramic heaters, 
  • thermocouple attachment units (TAU) 
  • pin welders 
  • hardness testers 
  • thermocouple wire 
  • insulation

Monday, February 27, 2017

Eliminate Costly Hopper Pluggage with Electric Hopper Heaters

hopper heaters
Modular, metal-clad hopper heaters
installed on large hopper.
Fly ash is a by-product of coal fired and waste-to-energy fired electrical generating facilities. Fly ash is a combination of dust and fine particles produced during combustion. Environmental laws require fly ash to be collected and not released in to the atmosphere. Large collectors called electrostatic precipitators combined with a system of filters extract fly ash from the flue gas and dispense the fly ash in large steel hoppers prior to being dumped in to containers and transported.

Due to the temperature differential between the hot internal temperature of the hopper and the cooler exterior, condensation forms on the internal wall surfaces, The condensation, combined with the fly ash, creates a concrete-like material that bonds to the hopper walls. The accumulation of this material eventually clogs the hopper to the extent it cannot be emptied. At this point, the only way to free the clogged material is with sledge hammers and pneumatic tools and long periods of downtime and the related expense.

To prevent the fly ash and condensate mixture from forming,
electric heaters are bonded or clamped to the exterior walls and throat of the hopper. Because the environment is normally very dirty with high vibration, “hopper heaters” are designed to withstand to meet these mechanical and environmental stresses.


Hopper heaters come in a variety of physical sizes, voltages, and wattages. Most often, hopper heaters come in pre-engineered sets that have been specified and configured by an applications engineer.

For more information on any hopper heating application, contact Hotfoil-EHS for a free consultation. Visit http://www.hotfoilehs.com or call 609.588.0900.

The Hotfoil-EHS Fusion 45 Induction Heating Console

Induction heating can improve your bottom line by decreasing weld failures, and decreasing setup and tear down times. The technology allows for accurate temp control, without heavy electrical service or complicated controls. The portability and ease of use will allow you to heat more welds faster.

For more information call Hotfoil-EHS at 609.588.0900 or visit http://www.hotfoilehs.com.

Sunday, February 26, 2017

Induction Heating Provides Welders Uniformity and Shortens Welding Time

Welder’s must pay strict attention when it comes to preheating, interpass temperature control and stress relieving. Torches takes too long and make it difficult to maintain heating uniformity. Plus there’s the issue with open flames and the expense of fuel.

Ovens are great for uniformity and control, but require transport and time. They're certainly not convenient.

A great alternative, one that provides excellent uniformity, control, and convenience, is induction heating.

Induction heating is unique because it uses molecular excitation as its source of heat, as opposed to open flames or external electric elements.

Induction heating works very quickly, and since there is no contact with the target piece, there are far less concerns about part contamination.  Many industrial processes use induction heating when very high temperatures and uniform control is desired.

Its important to note that the heat is created from inside the object itself, with no open flame or external electric heat source.

Induction heating is used to heat conductive materials. Developed in the early 20th century, it quickly became a popular choice for hardening military equipment parts during wartime. Because of induction heating’s controllability, speed and consistent output, its popularity continued to grow as new manufacturing and production methodologies were developed. Today, induction heating has become a popular technology for the welding industry to provide pre and post-weld stress relief.

Induction heaters provide temperatures and cycle times hard to achieve otherwise. By virtue of their high temperature capabilities, very fast heat up times, precise application of heat, excellent controllability, and ease of setup / breakdown, the use of induction heating has been know to cut 30% to 50% of total weld cycle time in real-life welding applications.

Induction heaters consist of a few primary components: An electromagnet and an electronic oscillator that passes a high-frequency alternating current (AC) through the electromagnet. RF (radio frequency) energy is transferred into the workpiece via electromagnetic waves. These alternating magnetic waves penetrate the object, creating electric eddy currents. These eddy currents (Foucault currents) flow through the target piece and produce heat.

Pre and post-weld heat treating (stress relieving) is a growing market for induction heating systems because it offers significant benefits such as excellent heat placement and distribution, lower cycle times, safety, ease of use, and efficiency.

For more information about induction heaters for pre and post-weld heat treating visit HotfoilEHS at http://www.hotfoilehs.com or call 609.588.0900.

Tuesday, January 31, 2017

Don't Let Frozen Aggregate Clog Your Process Equipment

FRP hopper heaters
FRP hopper heaters
FRP chute heater
FRP chute heater
Processing lines in coal mines, quarries, cement plants, mining facilities, and power plants have a special problem in very cold weather. The coal, sand, cement, ores, or other mined products they handle can freeze and cause equipment outages. The combination of trace moisture mixed with aggregate material, plus freezing temperatures, combine for major problems with conveyors, hoppers and chutes. When the aggregate hits the cold steel surface, it instantly freezes (flash freezing). The bond between the frozen aggregate and the steel wall is virtually unbreakable, and can cause long down-times with the equipment. Maintenance people have their own, time-tested curative solutions - torches and hammers - but installing preventative measures is clearly preferable.

FRP trough heater
FRP trough heater
The FRP heating panel, a waterproof, dust tight, and vibration resistant heater is an excellent preventative solution. FRP heaters are designed to be used in the high vibration, corrosive and dirty areas where they are installed. Available with FM approval for use in hazardous areas, they provide an easily customized panel that conforms to the shape and size needed to fit any chute or hopper. Additionally, they are lightweight, can be applied to flat or curved surfaces, and are very easy to install and maintain.

FRP trough heater
FRP trough heater
For more information on chute, conveyor, hopper or pipe heating, contact the experts at Hotfoil-EHS by visiting www.hotfoilehs.com or calling 609-588-0900.