Sensor Assemblies for MVE Cryogenic Freezers

MVE’s customer service has been receiving numerous calls about switching out a three-tube temperature sensor assembly from the dual tube assembly. For cryogenic freezers already in service, three tube assemblies can either be purchased as an accessory or with a new cryogenic freezer.

 

When you are placing the order for your cryogenic freezer, it is the best time to make sure that you receive the correct sensor assembly. Two-tube sensor assembly comes standard with liquid nitrogen freezers. Have your customer service representative enter a second line item replacing the two-tube assembly with a three-tube assembly. If you would like a three-tube assembly, find the part number for the three-tube assembly below.

 

Freezers	Tube Length	Dual P/N	Three P/N
1842P	26”	11747450	11793341
800, 1500 series	39”	11747468	11793350
Rest of 1800 series	44”	11747476	11793368

 

 It can still be ordered at a later date if you fail to order the correct one at that time. You will not get credit for the dual sensor until it is returned however, and you will be required to obtain a return authorization number.

LAB 20 Dewar Design Change

The neck tube inner diameter of the Lab 20 was to increase from 2” to 2.2”. That change necessitates a different sized discharge device and pouring spout. The cryogenic discharge device to be used with the larger 2.2” neck tube is Part Number 13484139. We will continue to carry the older style 2” discharge device, Part Number 13464867. The cryogenic pouring spout will change from Part Number 9711909 to Part Number 9720729 to fit into the 2.2” neck.

TEC 3000 Alarm Delay

There is a delay on the TEC-3000 alarm conditions, differing from the TEC-2000 which alarms immediately. For example, there is a one minute delay from when the measured temperature exceeds the alarm setting to when the alarm is triggered. The indicated temperature will be well beyond the alarm setting by the time the alarm sounds if you are performing a temperature alarm test, in which the probe is rapidly warmed.

IATA/UN Vapor Shipping System

All four components, of which the Cryoshipper XC VSS is made of, must be present to maintain IATA certification. The four components are the primary container, secondary container, Cryoshipper Dewar, and plastic shipping container. The package is no longer certified to legally ship biohazardous samples if any of these are missing, substituted, or there has been a replacement of any individual parts to the cryogenic components. All replacement parts must be purchased through Chart in order to maintain certification.

 

Notice

 

For the secondary container, the relief valve must be labeled at 15 psi. By looking for the number “15” stamped onto the valve body, you can verify this label. Please contact your distributor or Chart MVE immediately if you notice something different from this.

Question and Answer for HE Series Liquid Nitrogen Freezer

Q: For HE models, when did MVE start using center-mounted sensor tubes?

A: In January of 1995 MVE began installing centrally mounted sensor tubes on HE liquid nitrogen freezer models. Any units purchased prior to requiring temperature probes to be inserted through the lid cannot utilize the center sensor assemblies.

 

Q: Are these two lids 11008340 and 10727414 used on a 1211 interchangeable?

A: The two lids are not interchangeable. Wagner hinges 11008340 were used on some, while with Frigidaire hinges 10727414 were used on others. There is a third lid now being put on production which is not interchangeable with any previous lids. Please make sure to have your serial number ready whenever ordering a replacement so customer service can determine the precise age of your cryogenic freezer, which ensures that you receive the proper replacement lid.

 

Q: For the TEC 3000 download, can I use either converter kit (RS232 or USB)?

A: Of course, the converter kits are interchangeable and either the TEC 2000 or TEC 3000 can be used to download data. 10740221 is the part number for the RS232 kit and 13376947 is the part number for the USB kit.

 

Downloading Data from the TEC 2000 and TEC 3000

On the same network TEC 2000s and TEC 3000s can be connected together. RS-485 protocol is supported by TEC 2000s as well as TEC 3000s. Make sure that all TEC 2000s are set at a baud rate of 9600 and all TEC 3000s are set at 9600 N81 in order to successfully set up a mixed network. A PC is connected by both controllers in the same manner as a USB converter, which connects to the computer’s USB port use RS485. The USB port of the computer is emulated on a serial port. No external power supply is required as the USB port is used as the physical connection and the power supply for the converter. TEC 2000s should be set at a baud rate of 9600 in order to allow communication. Using ASCII as the port setting on the controller, TEC 3000s should be set at 9600 N81.

The SC 4/2V and Doble 11 specifications changes

For the SC 4/2V cryogenic dewar, the hold time has been reduced from 14 days to 13 days. The hold time for the Doble 11 cryogenic dewar has been also changed from 21 days to 17 days. This change is related to the amount of liquid nitrogen that the Doble 11 cryogenic dewar holds. The new design will only hold 3 Liters of liquid nitrogen while the old design Doble held 3.4 Liters. Check our new Cryopreservation Equipment Catalog for these specification changes.

Built In Time Delays for TEC 3000 Controllers

All alarms for the TEC 3000 controllers have a built in time delay. The audible and visual alarms will not activate until 60 seconds after the alarm condition is present, meaning any parameter (level, temperature, etc) exceeds the programmed high or low threshold (high temperature alarm, low level alarm, etc). For parameters that may temporarily exceed the programmed thresholds, the time delay is intentional and is intended to prevent “nuisance alarms”. When validating the function of the freezer, this behavior needs to be considered.

Consider the following procedure when testing the high temperature alarm on a freezer:

·         From the controller keypad, initiate “Hi Temp Alarm Test”. (In the “temperature settings” menu this function can be found).

·         Monitor the temperature of the probe being tested. Measure the amount of time it takes for the audible alarm to sound, to when the temperature exceeds the high temperature alarm setting (default is -110°C). This time should be 60 seconds.

·         The controller is functioning properly if the alarm sounds 60 seconds after the temperature exceeds the high temperature alarm setting.

Note

Before the audible alarm sounds it is common for the displayed temperature to read -50°C or more because the temperature probe heats rapidly during the high temperature alarm test. Due to the previously mentioned built-in time delay for all alarms this operation is normal. Consult the TEC 3000 Technical Manual or contact Technical Service at 1-800-482-2473 for questions regarding alarm delays.

 

Gordinier Cryogenic Tank Switcher

To work with the TEC 3000, Gordinier has developed a cryogenic tank switcher, but it only works with correct installation. If installed improperly, the cryogenic tank switcher can cause the cryogenic freezer to fire the hot gas bypass solenoid at all times when connected to the cryogenic freezer. This results in pouring liquid nitrogen onto the floor of the facility. The cryogenic freezer functions normally when the Gordineir equipment is installed properly.

In two seperate places, this tank switcher splices into the wiring of the TEC 3000. Between the controller and the 12 pin connector is the first place at the bottom of the TEC 3000. Between display panel and the RJ45 connector that plugs into the display is the second place is inside the controller. This version of Gordineir’s tank switcher only functions properly if a certified Gordinier technician installs the switcher. Chart MVE has said that the customer voids the 2 year warranty of the controller if a Gordineir switcher has been hooked up to one of Chart’s TEC 3000 units.

Cryogenic Temperature Sensor Probes

Although TEC 3000 use different temperature probes in liquid nitrogen freezers, the function is identical when compared to TEC 2000. The TEC 2000 uses only two wires and hence the temperature probe casing has a smaller diameter. On the other hand, the TEC 3000 uses three wire as a result it has a larger diameter (despite the fact that only two of those three wires are in use). They carry an accuracy of 0.12% in which both are 1000 ohm platinum RTDs. Keep in mind that the temperature with an precision of plus or minus 2°C is displayed by TEC 3000 controller.

New Cork Material for Liquid Nitrogen Dewars

Liquid nitrogen dewars will have a different colored cork material as of the 1st of January, 2008. These changes will start on the Lab series and eventually be found on the whole aluminum line of liquid nitrogen dewars. Instead of the older yellow cork the new cork material will be pink. The pink cork is 250 Styrene whereas the yellow cork material is A400. The pink cork not as hard as the yellow but it is a much more efficient insulator. You may still find yellow corks with the liquid nitrogen dewars as we deplete our existing stock.

Static Evaporation Rates for Liquid Nitrogen Storage in Cryogenic Freezers

Evaporation rates are not shown in Chart’s marketing brochures, although, for each series of cryogenic freezers there is a general list of static evaporation rates. Static evaporation rates are approximations only. The tank would have to be untouched for a freezer to be static. Since the liquid nitrogen freezers are always used in non-static conditions these figures can only be taken as estimates. Evaporation rates can be changed significantly by a variety of uncontrolled parameters. Below is a list of rates for liquid nitrogen storage.

 Open Top Models High Efficiency

Model	SER (L/day) Model
MVE 103	4.1
MVE 205	3.0
MVE 510	6.2
MVE 616 & C	8.5
MVE 808	8.0
MVE 1223	13.0
MVE 1318	8.5
MVE 1426 & C	14.0
MVE 1839	13.0
800 series	5.0
1500 series	7.5
1800 series	12.5
1842 (old 1830)	12.0

TEC 3000 for Cryogenic Freezer Upgrade

Before powering up the TEC 3000, be sure that the wire harness configuration is accurate while upgrading a liquid nitrogen freezer with a TEC 2000 controller to a TEC 3000 controller. Overloading the internal circuitry of the controller can damage an incorrectly configured wire harness.

The existing 8-pin inline connector as well as the 2-pin battery backup connector (if it has been fitted with the battery backup option) is intended to accept the harness adapter, the 10-pin inline Phoenix receptacle that comes with the upgrade kit. The 2-pin battery backup connector must be connected to the pins 9 and 10 of the 10-pin inline receptacle while the 8-pin inline connector must be connected to the pins 1-8 of the 10-pin inline receptacle. You must be certain that the polarity of the wire harness adapter equals polarity of the battery backup connector, meaning that pin 9 of the receptacle must be attached to the (-) battery backup pin and pin 10 must be attached to the (+) battery backup pin. 

Operation of Manual Discharge Device

The cryogenic manual discharge device works through the difference of temperature. The nozzle is bare to the atmosphere which contacts the dip tube, which links to the liquid nitrogen. The liquid boils off as the liquid nitrogen is colder than the much warmer dip tube. When the vent valve is closed and seated properly the discharge device is installed correctly. The liquid nitrogen is vigorously expelled from the nozzle because the head pressure pushes on the liquid nitrogen. The full and warm liquid nitrogen dewar will build pressure much more quicker.