Tuesday, December 30, 2014

Electric Heating Systems for Liquid-Gas Vaporization

Liquid-Vapor Gas Heater
Electric Circulation Heater
Hydrocarbon and non-hydrocarbon based gas products are transported and stored at low temperatures. The most common examples of liquified gasses are liquified natural gas, butane, propane, nitrogen, and oxygen. In liquid form gases are more convenient and efficient to transport, however once at their destination, they must be changed back to the gaseous state.

There are many ways to accommodate the phase change from liquid to gas and picking the best option is dependent on many criteria including plant location, climate conditions, available energy sources, and infrastructure available.

Transitioning from liquid phase to gas phase is a gradual process usually taking place at higher pressures, through several containment vessels, heat exchangers or heating coils which slowly warms the liquified gas.

Some thermal heat exchanging systems use fluids such as hot oil, hot water or a glycol-water solution to efficiently transfer heat to the liquified gas.

Wednesday, December 24, 2014

Happy Holidays and Happy New Year from Belilove Company-Engineers

Happy Holidays from Belilove
We at Belilove Company-Engineers believe the magic of the holidays never really ends, and the most important gifts we share are family and friends. Thank you for a wonderful 2014 and we wish you peace, love, and prosperity in the upcoming year.

Friday, December 19, 2014

Control Valve Challenge in Rocket Propulsion Application

cryogenic control valve
Cryogenic
Control Valve
Challenge: To provide a bubble-tight shutoff control valve for liquid oxygen being used in a chemical steam generator in a rocket propulsion testing facility.

Customer requirements: A cage-less design, cryogenic globe control valve that would safely provide fast and consistent Class VI shutoff of liquid Oxygen.

The Solution: Control valve manufacturer Trimteck designed and manufactured a custom 2”, CL300, cryogenic angle/split body valve fitted with piston cylinder actuators. The seat is held in place by the rugged split body configuration without the need for a cage or retainer (normally required for liquid Oxygen valves). The seat maintains its position and is kept at even pressure with the help of eight (8) equidistant bolts that tie together the upper and lower body pieces. Additionally, this “sandwiching” reduces line torsion effects and the adverse effects of vibration on the valve seal. Finally, a custom designed soft wafer seat insert is provided so that seat maintenance can be done quickly and inexpensively.

Wednesday, December 10, 2014

Advantages of Epoxy Electrical Feedthroughs Over Glass-to-Metal and Ceramic Seals

epoxy vacuum feedthrough
Epoxy Electrical
Vacuum Feedthrough
Advances in semiconductor and medical device development has continually challenged manufacturing processes in ultra-clean environments. Getting power and control signals into high vacuum chambers has always been difficult. The vacuum seal has to be tight and not allow any contamination so that product quality is maintained.

Historically glass-to-metal seals for wire feedthroughs have been the choice in these industries, but are constrained in size, geometry, flexibility and electro-magnetic shielding. At the same time, semiconductor and medical device equipment have an increasing need for higher power, more control, better monitoring, and increased signal shielding. These ever changing requirements, which push the capability of glass-to-metal seals,  open up opportunity for an alternative technology - epoxy electrical vacuum feedthroughs.

Engineered epoxy electrical feedthroughs offer the best of all technologies. Shapes, angles and curves are not a problem. Virtually any kind of shielded wire or cable can be used and still maintain a tight seal. And as equipment design requirements continue to challenge vacuum seals with space and shielding requirements, the advantages of epoxy vacuum seals look to be a promising solution as the technology itself continues to advance.

While glass-to-metal feedthroughs have advantages in high temperature and corrosive applications, many of todays semiconductor and medical device applications don’t see these conditions. In these lower temperature, and non-corrosive applications, the lower cost, easy prototyping and more flexible design capability of epoxy feedthroughs make them very attractive alternatives.

The epoxy's ability to flow and fill spaces completely make it an excellent choice for any special shapes and sizes a vacuum chamber may require for access.  For the most part, epoxy feedthroughs can be used in most applications where glass-to-metal or ceramic feedthroughs are used (with the exception of temperature and corrosion issues outlined above). In some applications, organics are not allowed, and the epoxy feedthrough would be excluded from these as well.

One additional advantage is that custom epoxy vacuum feedthroughs can be quickly provided in very small quantities for prototyping and R&D.

For more information on epoxy feedthroughs, visit this page.

Saturday, December 6, 2014

Selecting and Calibrating a Pneumatic Valve Positioner

Most pneumatic valve positioners are designed to work on both rotary control valves and linear control valves. While the linkage and orientation are different, the calibration procedure is the same.

When selecting an industrial valve positioner you should choose one that provides the following features:
  • Easy to install, calibrate and maintain.
  • An auto-calibration feature.
  • Be able to accommodate double acting (DA) or reverse acting (RA) set-up.
  • Error messages for troubleshooting.
  • Allow for fixed input signal testing.
  • Have a programmable characteristic curve with multiple points.
  • Have programming built-in to eliminate overshoot and hunting.
  • Low air consumption.
  • Have NAMUR mounting.
This video demonstrates the typical steps in calibrating a pneumatic valve positioner (in this case, an AT Controls SS2).