Tuesday, November 28, 2017

Application Survey for Industrial Flame Arrester

detonation flame arrester
Detonation flame arrester is one of several configurations
applicable to various installations.
Image courtesy Groth Corporation
A flame arrester operates by removing heat from the flame as it attempts to travel through narrow passages with heat-conductive walls. The arrester will stop a high velocity flame by absorbing heat away from the flame head, which lowers the burning gas/air mixture below its auto-ignition temperature, and creating an atmosphere where the flame cannot be sustained. The channels or passages in the flame arrester are designed to very efficiently conduct heat outward, but still allow the gasses to flow.

Many in-line flame arrester applications are used in systems that collect gases emitted by liquids and solids called vapor control systems. The gases are typically flammable. If an ignition occurs, a flame inside or outside of the system could occur with potentially catastrophic outcomes.

A vapor destruction system is a type of vapor control system that includes enclosed flare systems, elevated flare systems, burner and catalytic incineration systems, and waste gas boilers.

Vapor recovery systems are another type of vapor control system that uses in-line flame arresters. These systems include compression systems, vapor balancing, refrigeration, adsorption, and absorption.

Flame arresters are used in many industries including chemical, refining, petrochemical, pulp and paper, oil exploration and production, pharmaceutical, sewage treatment, landfills, power generation, and bulk liquids transportation.

The document below is a handy flame arrester application questionnaire. Please always consult with a properly qualified applications specialist prior to specifying, purchasing, or applying flame arresting devices.


Friday, November 17, 2017

Scotch Marine Boilers

cutaway view of two pass scotch marine boiler dryback configuration
Cutaway view of two-pass Scotch Marine Boiler
Image courtesy Williams & Davis Boilers
Boilers have a long history in the industrialization of the world. They were a primary source of motive power for many decades in the industrial revolution. Boilers continue to be an important source of both heat and motive power.

There is no shortage of lexicon in the boiler industry, with many legacy names for particular boiler designs. A Scotch Marine Boiler is a firetube boiler that was historically employed on ships. Firetube boilers channel the furnace combustion and resulting flue gases through an enclosure (for the furnace) and smaller diameter tubes. The shell of the boiler contains the water and steam, with the furnace and firetubes immersed within. Heat is transferred from the furnace and tubes into the water, producing hot water or pressurized steam as the unit design intends. Most of the heat from fuel combustion is passed to the water from the furnace chamber, with much of the remaining heat from the flue gases transferring from the firetubes. Once leaving the firetubes, the gases pass out of the boiler to a flue or chimney.

A dry-back boiler uses an enclosed chamber at the rear of the boiler to distribute the gases exiting the furnace section into the many firetubes. It is essentially just a box with the open entries to the firetubes and the open exit from the furnace penetrating its walls. The dry-back design facilitates access to the tubes for inspection and service.

There are other boiler configurations that serve to maximize various aspects of cost, service, and performance. Share your steam and hot water requirements with boiler and combustion specialists, leveraging your own knowledge and experience with their expertise to develop an effective solution.


Wednesday, November 8, 2017

Eccentric Rotary Plug Control Valve

eccentric rotary plug control valve
The MaxFlo 4 eccentric rotary plug control valve
Image courtesy of Flowserve Valtek

There is an extensive array of valves from which to select for a process control operation. Each candidate valve is targeted by its designers for a range of fluid applications, fortified with construction materials and design features specifically suited for meeting the challenges of that application range.

Flowserve, under their Valtek brand, developed a control valve that combines a number of useful design features. The MaxFlo 4 is an eccentric rotary plug valve intended for fluid control operations. The valve has some attractive design features.
  • There is no shaft extending through the flow path, leaving flow unobstructed when the valve is fully open (see the illustration in the document included below).
  • Valve trim provides tight bi-directional shutoff.
  • Metal or soft seat construction is available to accommodate a wide range of applications.
  • A variant provides flange to flange dimensions that allow the MaxFlo 4 to drop in as a replacement for standard size globe valves.
  • High Cv rating may enable use of a smaller valve, when compared to other designs.
  • Precise position control is delivered by the shaft form and plug mounting.
  • Double offset eccentric plug eliminates sliding of plug across sealing surfaces, reducing wear and required seal maintenance.
More detailed information is provided in the document provided below. There is a revealing cutaway illustration showing the mounting and movement path of the plug. Share your industrial process control valve requirements and challenges with a valve selection and automation specialist to get the best match of control valve to application.


Thursday, November 2, 2017

Lined Ball Valves

cutaway view of lined ball valve
Lining of ball valves extends their application to a range
of corrosive fluids.
Image courtesy Flowserve - Atomac
Lined valves of all types have an isolating layer of material that keeps the media from contacting the valve body, maybe even the valve trim itself. The purpose of the lining is generally to extend the useful life of the valve by eliminating the corrosive effect that may be imparted by media on the valve construction. Lined valves, with no exception I can think of, will have metal bodies. The lining can be any of a number of materials that will be selected based upon resistance to degradation by the process media under consideration.

Lined ball valves deliver the performance of conventional ball valves, coupled with the corrosion protection afforded by an appropriate lining material.

  • Low pressure loss
  • Quarter turn operation
  • Simple automation
  • Positive shutoff
  • Low to moderate operating torque
  • Compact

Options for the ball configuration are available to meet throttling or other requirements. Automation can be accomplished via a range of means. For more information, share your valve and automation challenges with application specialists and leverage your own knowledge and experience with their product application expertise.