Pre Weld and Postweld (PWHT) Heat Treatment Furnaces

pre post weld furnace
Industrial furnaces are used for pre and post-weld heat treating by welders and fabricators to heat-treat weldments or metallic parts. Industries that require these types of furnaces include pressure vessels and piping, storage tanks, building construction, bridge building, offshore platforms, petrochemical plants, power plants, and oil and gas refineries.

By using furnaces for PWHT,  stress introduced by the welding process is reduced and redistributed through the heating, soaking and cooling the weldment/machined surface. This greatly improves the weld properties. PWHT is most times mandatory in order to comply with welding codes and specifications for the welding of carbon steels, stainless/high alloy steels and work hardened steels.

pre post weld furnace
Fairly sophisticated control systems carefully follow mandatory heating and cooling profiles, as outlined by welding code. Control systems with thermocouples that monitor internal furnace temperature, along with weldment part temperature are usually included. These control systems also include the ability to ramp up to temperature and cool off over specified time intervals. Finally, the use of recorders or data loggers is common for quality control documentation.

pre post weld furnaceAdditional benefits of pre and post weld heat treating are:

  • Improved ductility and/or harness
  • Lower risk of brittle fracture
  • Improved metallurgical structure
  • Reduction in diffusible hydrogen induced cracking 


pre post weld furnaceMost pre or post weld heat treating furnaces are customized in one way or another, whether it size, total BTU output, energy source (electric, gas, oil), control scheme, door configuration, or having the furnace built on wheels or on rails.

pre post weld furnaceFurnaces can be designed permanently, portable, or field erected. By having the furnace local, or right on-site, companies eliminate the need to send parts out and thus save time and costs associated with shipping. Depending on the scope of work, its not uncommon for the investment made in a fabricated furnace to pay off within the first year.

For more information on any custom built pre heat or post weld heat treat furnaces, contact:


Hotfoil-EHS, Inc.
2960 East State Street Ext.
Hamilton, NJ 08619
Phone # 609.588.0900
Fax # 609.588.8333
Email: dap@hotfoilehs.com

pre post weld furnacepre post weld furnace

Multi-Operator Welding Systems

Aftek Quad Arc
Multi-operator welding system (Aftek Quad Arc 1200)
There are many different welding processes utilized in the welding industry today. Welding processes include stick arc welding, gas tungsten arc welding (GTAW), flux core arc welding (FCAW), shielded metal arc welding (SMAW), gas metal arc welding (GMAW), and air carbon arc gouging.

Most arc welding operations are performed using direct current from a DC power source an AC power source which has been rectified from AC to DC. Many industries use these welding processes in a wide variety of environments including factories, construction sites, power plant construction, boiler construction and repair, and shipyards.

Multiple operator welding equipment was developed to allow several welding modules to operate from a single common power supply. The power supply typically includes a transformer and rectifier to step down the supply voltage, and then convert the power from AC to DC.

Multi-station welding systems afford a number of advantages the principals of which are a lower initial capital cost, a much lower cost of installation, much lower maintenance cost and less power requirements as compared with single operator equipment. Multi-operator welding systems are practical and efficient as they provide a welding station where each welder has the ability to work. They provide for multiple simultaneous welding projects where workers can work efficiently and meet production deadlines.

The clear advantages of multi-operator welders:

  • Improved productivity
  • Lower total cost of ownership
  • Less equipment to transport
  • Reduced maintenance costs
  • Noise reduction

Portable Auxiliary Power Boxes (PAPB) for Convenient Source to Run Tools, Save Time, Improve Safety

Portable Auxiliary Power Boxes (PAPB)
Portable Auxiliary Power Boxes (PAPB)
30kVA (left) and 15kVA (right)
In many field welding situations simply having convenient access to 120 volt or 240 volt supply power to run auxiliary power tools such as grinders, stud guns, and drills is important. In some situations, bringing power to these locations can difficult or nearly impossible. Worse yet, short-cuts and quick fixes can compromise safety. While its not uncommon to have an available 480 or 575 volt power source, conversion to 120 or 240 volts is a challenge. Simply running extension cords can be impractical or present a safety hazard. What's really needed is a portable power box, with all necessary transformers, circuit protection and safety devices built-in to conveniently convert high voltage to 120/240 volt power.

Internal view of cabling and outlets
A new product by Hotfoil-EHS has been developed for just this situation. Named the PAPB (short for portable auxiliary power box), the new product taps into the available high voltage feed and puts convenient, usable 120/240 volt power right at the worker's location.

The PAPB is designed with small supplementary circuit breakers at each of the outgoing power connections for protection and ease of resetting. The main power supply is also protected by a main circuit breaker.
transformers
Transformers made in-house

Portable auxiliary power box's can be custom made and manufactured in virtually any size.  The ones pictured above are relatively small; 15kVA and 30kVA. 

Internal view
All PAPB's are made in the USA with major components being fabricated in-house.  All framework, tubing, sheet metal, transformers, wiring, and assembly is done at Hotfoil-EHS's production facility in Hamilton, NJ.  The units are 100% QC'd and tested  prior to shipping. When the equipment leaves the factory, it is 100% ready to go to work.

For more information, contact:

Hotfoil-EHS, Inc.
2960 East State Street Ext.
Hamilton, NJ 08619
Phone # 609.588.0900
Fax # 609.588.8333
Email: dap@hotfoilehs.com

The TAU: A Perfect Solution for Fast, Strong, and Inexpensive Thermocouple, Stud, and Pin Welidng

Thermocouple attachment unit (TAU)
Thermocouple attachment unit (TAU) used for creating
thermocouples quickly and inexpensively, plus welding
studs and pins to metal structures.
Are you buying pre-made thermocouples? Do you know how easy it is to make your own? Are you always looking for a fast and easy way to attach studs or pins to a target structure? A thermocouple attachment unit (TAU) is the answer. TAU’s will help you save time and money in the fabrication of welding thermocouples and stud/pin welding.

Thermocouple attachment units (TAUs) are small, self contained spot welders that achieve superior results for welding thermocouple junctions and attachment. They are portable and are easy to use. Also known as thermocouple welders, these units are provide a capacitive discharge (as the energy source) in a compact, self-contained, hand welding unit. They are designed to form very strong, free standing junctions in just seconds using standard thermocouple wire. There's no need for clamping, bracketing or strapping. TAUs provide a direct bonding method for thermocouples, pins and studs that is quick, easy, and low-cost while still providing accurate temperature measurement.

Thermocouple attachment units continue to enhance their power outputs which creates more potential uses for TAUs. Higher power output opens doors to a broader application base. Higher power TAUs can be used to weld thermocouple pairs but also can be used to weld studs, rods and pins to a wide variety of metal structures. For example, a common use for TAU’s is attaching insulation pins to welding insulation blanket support.

An internal power supply constantly recharges an internal battery giving the operator portability in field thermocouple welding. Readily available controls allow for easy adjustment based on wire size and material.

Thermocouple attachment units offer a very convenient and economical method of forming and attaching thermocouple sensing wires, studs, and pins where and when you need them. Models vary based on requirements. Some models accommodate a greater range of wire sizes and materials, handling wire up to 14 gauge and capable of creating weld junctions in under a second. Because the power supply provides a short recharge interval, multiple welds can be done very quickly (4-6 welds per minute).

For more information on thermocouple attachment units, contact:

Hotfoil-EHS
2960 East State Street Ext.
Hamilton, NJ 08619
Phone # 609.588.0900
Fax # 609.588.8333
Email: dap@hotfoilehs.com
www.hotfoilehs.com

Electrostatic Precipitator and Bag House Hopper Heaters Prevent Fly Ash Production Problems

hopper heaters for power plants
Coal fired power plants must manage fly ash properly.
Coal fired power plants in the United States require the use of electrostatic precipitators or bag houses to filter out very fine fly ash particulate incorporated in the flue gas. The ash is collected as the flue gas passes through filter bags or by large electrodes, and then falls into collection hoppers.

As the hot fly ash cools, condensate on the hopper walls can form. The mixture of dry, sulfur rich fly ash and water is very problematic, so it's very important to keep condensation from forming in the collection hoppers. The mixture of water and fly ash can cause clogging (or “pluggage”) in the throat of the hopper,  and more importantly, the residual sulphur in the flue gas will combine with the condensate to form sulphuric acid. The suluric acid attacks the hopper walls from the inside causing corrosion, weakening the walls and creating significant (and costly) maintenance issues over time.

hopper heaters for power plants
Fly ash hopper with heaters.
Efficient and continuous fly ash removal is critical for all coal fired power plants. Collection hoppers are an integral part of the removal process. Pluggage or inoperable hoppers are a known issue to engineers and maintenance crews. The constant maintenance and excess of down time seriously hinder a plant’s ability to manage the fly ash production rate. Slower fly ash production means limiting energy production and efficiency. A power plant’s electricity production is directly proportional with its coal combustion rate which, in turn, directly effects the fly ash production rate. Plant maintenance personnel usually attempt to remedy ash system failures in real time by deactivating the affected hopper while continuing to generate power and ash. In some situations (to prevent boilers shutdowns) ash will be dumped on the floor, requiring costly clean up.

The evacuation and management of fly ash is much easier when the ash is kept hot. One of the most common ways to maintain elevated fly ash and hopper temperature are electric hopper heaters attached to the external hopper walls. Hopper heaters play a very important role in the removal of fly ash from precipitators and bag filter hoppers by keeping the hopper temperatures operating above the flue gas acid dew point. The hopper heater’s sole function is to preheat the hopper and the internal environment to prevent the formation of moisture and the resulting clumping of fly ash and development of sulphuric acid.

hopper heaters for power plants
Flexible heating element used on hopper throat.
Hopper heaters are designed for the dirty, high vibration environment of a power plant. They provide the optimum watt density for proper conduction through the hopper wall and for uniform heating. The are available in square, rectangular, and trapezoidal shapes to accommodate any hopper design. Ancillary flexible heating blankets are available for poke tubes, man-ways, and cylindrical throats.

The use of electric hopper heaters on electrostatic precipitator and bag house fly ash collection systems is a time proven, effective way to prevent condensate formation and the resulting clumping and corrosive acids in hoppers, thus facilitating a better opportunity for uninterrupted fly ash production.

For more information, contact:

Hotfoil-EHS, Inc.
2960 East State Street Ext.
Hamilton, NJ 08619
Phone # 609.588.0900
Fax # 609.588.8333
Email: dap@hotfoilehs.com
www.hotfoilehs.com

Aftek at CastExpo 2016

The single largest trade show and exposition for metalcasting in the Americas, CastExpo, is being held in the Minneapolis Convention Center April 16 through the 19th, 2016.

Held every three years, CastExpo offers metalcasters, suppliers, and casting buyers and designers the opportunity to connect and educate themselves on the latest metalcasting has to offer.

Aftek Quad Arc Welder
Aftek Quad Arc Welder
The Metalcasting Congress technical program and additional workshops cover a wide range of topics. Identify which specific technical presentations and workshops you would attend that is relevant to your company and its immediate and future challenges.

Aftek (Division of Hotfoil-EHS) will be attending displaying their Quad Arc heavy duty arc welder, Quad Arc are:
designed for low maintenance in harsh environments. Features of the
  • Submerged arc.
  • Air arc gouging to ½” electrodes.
  • FCAW (flux core MIG) all positions, self or gas shielded.
  • Performing outstanding results on stainless, or steel castings.
  • Power sources, rated for 100% duty cycle. Amperage range adjustable in 5 amp increments.
  • Designed with Harsh Environment in mind.
  • Designed with a single transformer on the MV1500G1.
  • Powder Coated for a long lasting durable paint job.
  • Protected with thermostatically controlled alarms on the rectifiers and the transformers.
  • Designed to shut down if any of the Alarms are Energized.
  • Easy-to-reset overload breaker for circuit protection.
  • Optional protection for incoming Primary Power.
  • Dimensions 51” Wide x 40” Deep x 57” Tall.
If you're planning to attend CastExpo this year, please plan on stopping by Booth 1346 and visit. 

Custom Fabricated Gas Trains and Nozzles Capable of 10 Million BTU Output

Gas Trains designed with safety in mind. All gas trains have dual valves on the pilot line and main, low gas pressure switch, high gas pressure switch, and proof of closure.
Fully automatic units are supplied with a 4-20 mA controlled actuator that regulates gas. The control system includes a power-on switch, power-on light, master controller with 4-20mA slave controller, air-on light, gas-on light, ignition-firing light, burner-on light, high-fire light and high-fire switch. Should the limit switch fail system come with a dump button and procedure for clearing the gas out of the lines. Construction is 1.5 inch powered coated tubing.

Other features include:
  • 15HP blower motor than can move up to 2200 cubic feet/minute 
  • Damper with a handle wheel for adjustment 
  • Blower is powder coated for longevity 
  • Starter box incorporates a lockable disconnect 
  • Supplementary circuit breaker 
  • Starter contactor 
  • 750VA transformer 480/120 for power to the train. 
Burners are 316 stainless steel. Three standard sizes: 6-10 million BTU; 3-6 million BTU burner; 1 million BTU burner.






For more information. contact:
Hotfoil-EHS, Inc.
2960 East State Street Ext.
Hamilton, NJ 08619
Phone # 609.588.0900
Fax # 609.588.8333
www.hotfoilehs.com
Email: dap@hotfoilehs.com