Cryogenic Discharge Device Transfer Hose

Now, MVE Chart sells a transfer hose which can be fitted to a liquid nitrogen freezer’s discharge device. This stainless steel transfer which comes standard with a phase separator hose, is two feet long and ¼ inch in diameter. The following part numbers should be referred for ordering purposes:

 

Phase Separator Size ..................................Part Number

Small ..............................................................14044143

Medium ..........................................................14044151

Cryogenic Fire Codes and Liquid Nitrogen Freezers

National Fire Protection Association has not put forth any codes that requires liquid nitrogen freezers or non-pressurized liquid nitrogen dewars to be secured to a wall. Each state or locality can pass more stringent codes, as long as the codes are not less relaxed than the established NFPA codes. Be sure to confirm with your local codes/ordinances to find if there are any variations from federal regulations. A good source of valuable information can come from your local fire inspector but remember the following while working with an inspector:

 

• Make sure the inspector refers to exact ordinance code violations when the citations are issued.
• Do not be afraid to question violations while working with the inspector
• You are eligible for a grace period to fix potential violations before any fines are assessed.

Cryogenic Freezer Operation Manuals

For each liquid nitrogen freezer, the MVE Chart does not hold precise user manuals; On the other hand, TEC 2000 and TEC 3000 manuals as well as the TEC 3000 Quick Start Guide, are very much available at www.chartbiomed.com. You can browse through the Resource Library to find resources on TEC2000/3000. This will bring you to associated literature where you can select the ones you may be interested on looking at.

To Disable a Temperature Probe on the TEC 2000

1. The cryogenic temperature probe which you would like to disable needs to be removed.
   
2. To cycle the power simply unplugging the cryogenic controller’s power source and plugging it back into the controller and remember to disconnect if your liquid nitrogen freezer is equipped with battery backup.
   
3. “DIAG ERROR SENS A” will be displayed on the cryogenic controller and will show “DISABLE ALARM? YES OR NO” 
   
4. Opting for “YES” is equal to disabling the port.
   
5. If desired, repeat this procedure for port B.
   

Broken Cryogenic Locking Tabs on Liquid Nitrogen Dewars

On some MVE Dewars comes a welded locking tab. In case the locking tab is broken beyond its utility, then the cryogenic locking tab must be re-welded back onto the liquid nitrogen dewar. The liquid nitrogen dewar needs to be returned to Chart’s facility in New Prague, Minnesota. Take up this alternative only if necessary because welding the locking tab onto the cryogenic Dewar gives grounds for risk to the integrity of the vacuum.

New Blog Format - MVE Chart Tech Tips

Thus far, our (Princton CryoTech's) blog has been a fairly random assortment of technical articles and snippets of information. 

As of tomorrow, December 16, 2008, we will begin to post technical articles on cryogenics from the resource center from MVE Chart.

These articles contain a range of information about MVE Chart cryogenic products. We will present them starting with the newest information first, and working our way down the list, as so it is easily found in our archives. 

Please dont hesitate to email us for specific information that you dont find here.

Freezer Racks Question and Answer

Q: Will the evaporation rate decrease if 6 more freezer racks are added?

A: No. Adding more freezer racks increases the heat transfer paths to LN2 as well as the evaporation rate. This is apparent when aluminum vertical freezer racks are being used since aluminum has a greater thermal conductivity than stainless steel. The result of evaporation rate is minimal when stainless freezer racks are being used. There is an added benefit to using aluminum freezer racks though; because of a slightly higher evaporation rate, the cryogenic freezer is filling slightly more frequently, essentially ‘charging’ the liquid nitrogen vapor with a fresh, cooler supply, meaning that the vapor temperatures inside your vapor phase freezer will be slightly cooler when using aluminum freezer racks.