Skip to content

Cold Trap - KF-25

by Bhogart

BHOGART Dry Ice Cold Traps are the simple solution to effective terpene recovery. Made in the USA from the highest quality stainless steel, this trap is rated for ULTRA HIGH vacuums. Its simple design Tri Clamp Lid has few moving parts making it durable and easy to use. Cold traps typically last 15-20+ years and with a return on investment of just a couple weeks, enjoy the benefits year after year.

Working Principle

Cold traps are specially designed heat exchangers for trapping the condensate. The trap is cooled below a specific temperature range in order to condense valuable or dangerous chemicals. The cold trap works by condensing vapors into a liquid on the traps surface area which is collected in the base of the trap. The colder you get the trap, the more stuff can be condensed and trapped. Cold traps are attached to a vacuum system between the vacuum pump and the vacuum chamber in order to prevent solvents and other corrosive compounds from reaching the pump.

Methods for Cooling

Ice (water): Ice melts at around 32 degrees which makes it especially well suited for trapping alcohol or other high boiling point compounds. Ice is not cold enough to freeze water in the trap or condense low boiling solvents like butane. This combined with the availability of ice makes it an attractive option when used to keep contamination out of the pump. Ice keeps the trap cold enough that anything with a boiling point above 50C will be collected in the trap keeping the vacuum pump clean.

Dry ICE: Dry ice is frozen CO2 and does not melt due to CO2’s vapor pressure. Instead frozen CO2 turns directly from a solid to a gas as it sublimates which is why it is called “dry” ice. CO2 sublimates at a much lower temperature than water melts, -109.2 degrees Fahrenheit to be precise. However heat transfer is never 100% efficient and when using pelletized dry ice alone, the trap gets down to about -40 Fahrenheit. At this temperature, highly volatile molecules such as terpenes will collect in the trap along with dangerous solvents such as butane. In high vacuum systems the constantly reducing pressure leads to product loss from the trap, the colder you keep the trap the less that happens. Dry ice can be used around the outside of the cold trap to keep the terpenes and other valuable components trapped during your vacuum down process .

Dry ICE with IPA(isopropyl alcohol): Dry ice is extremely cold, but it’s hard to use dry ice to cool something else that cold. This is because the dry ice has limited surface area and air is a poor conductor of thermal energy. In order to increase the efficiency and “cool” faster, a liquid media such as isopropyl alcohol or antifreeze can be used. Heat (thermal energy) is transferred through water almost 20 times faster than air making it especially good for heating or cooling. When using an isopropyl bath the cold trap can get down to -67 or below which is more than adequate to trap terpenes of all kinds. The trap is so cold that water will collect in significant quantities and freeze covering the surface area of the trap. The reduced surface area also reduces the traps overall efficiency.

Liquid Nitrogen: Liquid nitrogen is the ultimate extreme cold, boiling at -320.4°F. Liquid nitrogen is cold enough to freeze gases such as butane or propane. Nothing gets through a liquid nitrogen cold trap because almost everything condenses at -300 degrees. Liquid nitrogen cold traps are used in ULTRA high vacuum applications in order to increase pumping efficiency. Liquid nitrogen is so cold that liquid oxygen can form creating a potentially dangerous situation. Extra precautions must be taken in order to purge oxygen from the system in order to make it safe to use. Liquid nitrogen is so cold that it’s used in ultra high vacuum applications to keep ALL contaminants from reaching the pumping system. It is also important to note the trap is so cold that water will collect in significant quantities and freeze covering the surface area of the trap. The reduced surface area also reduces the traps overall efficiency.

Benefits of using a BHOGART Dry Ice Cold Trap:

  • Keeps the vacuum pump clean.
  • Keeps corrosive chemicals out of the vacuum pump.
  • Collects terpenes and other volatile compounds.
  • Achieve faster vacuum down time.
  • Achieve deeper vacuum levels.
  • Prevents oil from the vacuum system from entering the system.