Unit is insulated enclosure designed to contain liquid nitrogen. It also includes set of stainless steel rotating rods for holding vessels containing liquids to be frozen, and electric drive mechanism for rotating these rods. Present device will accept 10 vessels at a time

Kelbaugh, B.

Owen, C.

Picciolo, G. L.

English

NASA Technical Reports Server

Sprockets 
Teflon 
Guide 
Drive 
Mechanism 
(See Detail 
on Top) 
Insulation 
I 
Main 
Chamber 
Rotating 
Rods
October 1973	 B73-10253 
NASA TECH BRIEF	
A 
Goddard Space Flight Center 
NASA Tech Briefs announce now technology derived from the U.S. space program. They are issued to encourage 
Commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Automatic Device for Shell Freezing of Liquids 
Chain
"Detail" 
is	
CoverFront 
Cover for Main 
Chamber
Automatic Device for Shell Freezing of Liquids 
• 
(continued overleaf) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States	 i.iformation contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19730000253 2020-03-17T07:14:22+00:00Z
. 
The problem: 
Many solutions especially those containing bio-organic 
compounds deteriorate during extended storage at both 
room temperature and subzero temperatures. One com-
mon method of preventing this deterioration is by 
freeze drying (lyophilization). Lyophilization is best 
accomplished by first freezing the liquid at liquid 
nitrogen temperature in a thin layer (shell freezing) on 
the interior surface of the lyophilization vessel. Typi-
cally, the liquids are poured into vessels which are then 
placed on a rack composed of parallel rotatable stainless 
steel rods. The rack is positioned inside a tank which is 
filled with liquid nitrogen. These rods are manually 
rotated to achieve uniform freezing. Manual rotation, 
however, has three disadvantages: (1) it is slow, (2) it is 
nonuniform, and (3) it is hazardous because the operator 
is working in close proximity to the liquid nitrogen. 
The solution: 
A unit was developed which automatically shell 
freezes the liquids without the manual operation. 
How it's done: 
The unit is an insulated enclosure (see figure) designed 
to contain liquid nitrogen. It also includes a set of 
stainless steel rotating rods for holding the vessels 
containing the liquids to be frozen, and an electric 
drive mechanism for rotating these rods. 
The main container in the unit for holding the liquid 
nitrogen is constructed from 1.6-mm (0.062-inch) stain-
less steel and is bound by an inner and outer chamber, 
separated by 1.9 cm (0.75 inch) of insulation. 
The rotary rods are made from 1.3-cm (0.5-inch) 
diameter, 1.7-mm (0.065-inch) wall stainless steel tubing. 
The portions of the rods that are in liquid nitrogen are 
insulated from the sprocket end of the tubes. The
sprockets are chain-driven and revolved at 45 rpm by a 
motor. A Teflon guide is used to hold the drive chain in 
contact with the sprockets. To prevent the drive 
mechanism from freezing, a blower unit (not shown) is 
included, to maintain the flow of room temperature air 
across the rotary sprockets. 
In use, vessels containing the liquid to be frozen are 
placed between the rods. The rods can accept "essels up 
to 500 ml in size, and with bushings placed around each 
rod, will accept vessels as small as 3 mm (0.125 inch) in 
diameter. After the vessels are installed, the blower and 
the motor are turned on, and liquid nitrogen is intro-
duced into the main chamber to the insulation point of 
the rotating rods. The rods are then rotated at a constant 
speed until the liquids are frozen, which takes about 30 
seconds. At this point, the vessels are removed and a new 
batch of vessels can be introduced. The present device 
will accept 10 vessels at a time. 
Note: 
No further documentation is available. Specific ques-
tions, however, may be directed to: 
Technology Utilization Officer 
Goddard Space Flight Center 
Code 207.1 
Greenbelt, Maryland 20771 
Reference: B73-10253 
Patent status: 
NASA has decided not to apply for a patent. 
Source: Burton Kelbaugh, Clifton Owen, and

Grace Lee Picciolo

Goddard Space Flight Center

(GSC-1 1737)
. 
B73-10253	
-
	 Category o4,05


Automatic device for shell freezing of liquids

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server