Manual for filling
liquid nitrogen2022.05

Chiba University
Department of Science1.Unlock the door with a bar code .

Bar code reader
Place a user’s bar code below a bar code reader.

Old type

When the bar code is read, the door is temporarily
unlocked. If the door is left open, a buzzer willsound and the door must be closed. When thedoor closes, it will automatically lock.
* Press the top button to temporarily open thedoor.

New type

Keep a small
distance2. Place your dewar in the correct position on the scales.
For dewar with wheels, ensure the wheels are locked.

3. Press and turn latch to access the bar code reader and refill controls.

②Turn①PressRemove the bar code reader and scan the bar code which corresponds with the dewar followed by youruser’s bar code.
* Never look directly into the laser on the bar code reader.
* You will hear a tone and the green light will be turned on if you have successfully scanned the barcode.

①②

The control panell will desplay the dewar number and the maximum refill amount etc.
If user’s code and dewar code do not correspond, you will not be able to proceed this point.
If you have the correct numbers, the refill button will begin to flash.
Current amountMaxumum amount

Start

StopBuzzer reset

Dewar numberflash
If you wish to reset this process, please press the stop button. Activate the button once without holding.
Also if there is a delay, the process will automatically be cancelled and reset.
In this case, the display will show all zeros. Rescan the bar codes

4. Before proceeding further, shut valve completely.

openclose5. Set the supply hose.
The hanging cable reel can be fixed in this position when it makes a "crunching" sound when pulled. Whenthe cable is pulled further and does not make a "crunching" sound, it is wound upward and returns to its
original position. The "fixing zone" with the "crunching" sound and the "winding zone" without the soundalternate. Each container has a different height, so it is fixed at a suitable position.

6. Grip the hose firmly and press the start button.

Start

Depending on the temperature, the machine may need to complete a precooling process. Please wait
until this process is taking place.
Hot gas from the hose will escape through a vent during the precooling process

Once precooling process is complete, the refill lump will be turned on.

7.Open the valve slowly.
If the opening is too small, only gas will come out without cooling. Please open to some extent.

At first, the evaporated nitrogen gas is vigorous as it comes out. As it cools and converts to liquid
nitrogen, the pressure settles down.

<Safety Stop Function>
This device detects the amount of weight change during filling. If the change in weight is zero for a certain
period of time, the unit automatically comes to a safety stop. If the manual valve opening is too small,liquid nitrogen may not accumulate and the safety stop may occur. Please open the manual valve a littlemore. Also, when a large capacity container is started from a warmed state, it tends to not accumulate
easily and the amount of change becomes zero because of its large heat capacity. If the safety stop occurs,
please try again.
Do not block the mouthof the container.
<Making a gap>
Make aSome people hold the mouth of a liquid nitrogengap
container by the shade of the supply hose. This isdangerous because the mouth of the container isblocked and the evaporated nitrogen gas loses its
escape route, causing the internal pressure toincrease. Make a gap at the mouth of the container
to allow the nitrogen gas to escape.

When the filling volume reaches the set value, the machine stops automatically. The completion lamp
will light and a buzzer will sound, please release it by pressing the buzzer reset button.

Buzzer reset

8.Don’t forget to close the valve.

9. Return the hose to its original position.

When the cable reel is pulled, it alternates between "fixed" and "rewind." If the cable is pulled downslightly, it will be rewound upward and return to its original position. Some people pull more thannecessary, or pull with force, but please do not do this as it may cause malfunction. A slight pull issufficient.

If you try to return the supply hose to its original position without winding it upward, you will have tolift the weight of the supply hose yourself, which is heavy. This will also put a load on the supply hose.
If the supply hose is wound up, it is hung high, so it is light and easy to return it to its original position.
And there is no load on the supply hose.

×○Light whenhung

Wound up state

Heavy to putback in place

Unwound stateBe sure to return the supply hose to its original position. Leaving the supply hose hanging isdangerous if it is blown by a strong wind.

×○

10. Close the door securely.
Be careful not to pinch the cord.

11. When leaving, press the unlock button to open the fence door.
Pressing the top button temporarily unlocks the door.

TemporaryunlockingContinuous
unlockingIf the door is not locked, there is a possibility that you have pressed the button by mistake. If the bottom
button is pressed wrongly (the red light will be on), correct to the normal situation by pressing thebutton again (the red light will be off).

ON：
Unlocked×

OFF：
Locked

12. Confirm the door is locked.
The door will automatically lock after a few seconds pressing the top button.

○Appendix＜Bar code reading＞[In the case of an old type bar code]
If it is difficult to read, try changing the angle or distance between the bar code and the reader. The bar
code tends to be readable the moment it is changed, rather than when it is held still. Keep the distanceso that the red laser beam hits the entire area of the bar code. If you are too close, the bar code cannot
be read.
[In the case of a new type of bar code]
The bar code is narrow, so you can get closer to it. Sensitivity is also good.
*Please contact us when you wish to exchange the bar code for a new one.

Old typeNew type

Sunlight reduces the barcode reader's reading sensitivity. You can increase the reading sensitivity byholding up a notebook or your hand to create a shadow, or by turning the container to face the darkerside.

＜Reset function＞
If the bar code reading fails or the start button does not light up, press the stop button. The stop button
has a reset function. (Do not press and hold.)

Stop

Please confirm that the display has returned to the initialized state of "0000" before reading the barcode again.

Never "press and hold" the stop button. It will change to another mode. If the display is in another modeas shown in the picture below, press and hold the stop button again to return to the normal mode.

Another mode

×Normal mode○＜Reset function 2＞
If you still fail to reset the system, remove the dewars from the scales, then switch the power off.

Nothing on the scale

Switch the power back on and then the system will be reset.
If this fails, call the engineer.

＜Manual stop＞
If you do not require to fill the dewar to it’s maximum value, press the stop button once the valueequals the desired value.
For example, if the dewar is a 100L dewar and you require it half full, press the stop button once thefilling value equals around 50L.

StopAlso, if the overflow occurs during filling and the filling amount does not reach the set value, press thestop button to manually stop the filling.
If this happens every time, the setpoint is probably wrong. Please contact us so that we can change thesetpoint.

＜Common problems＞
1. the machine stops automatically even though it is not full.
1-1. Insufficient flow rate
［Solution］ The flow rate is probably low, so try opening the manual valve more.
The safety stop function of the device may have been activated. During filling, the device iswatching the weight change. If this weight does not change during a certain period of time (first
120 seconds, then every 40 seconds), the solenoid valve is closed and filling is stopped for safety
reasons.If the flow rate of liquid nitrogen is low, it evaporates in the container and does notaccumulate. Therefore, it is thought that the amount of change is insufficient and the safety stopfunction is activated. Since a container with a large capacity has a large thermal capacity, if you
try to fill the container from room temperature, it may not accumulate even with the manual valve
fully open, and the safety stop function will stop. In this case, please try again.
1-2. False detection［Solution］ Make sure that the operator does not have his/her foot on the scale.
The operator's weight will be mistaken for the completion of filling and the machine will stop.
Please be careful not to step on the scale.
Also, please inform us of any data that has been marked as filling complete by the operator'sweight, as it will be subject to billing. We will delete the data.

2. solenoid valve does not close
2-1. Mechanical non-conformity［Solution］ Close the manual valve to cut off the flow.
When the flow of liquid nitrogen stops, the solenoid valve tends to close. Open the manual valve
again and check if the solenoid valve has closed. If there is no flow when you open the manualvalve, the problem is solved (a small amount of gas can flow).If it still does not close, there may
be a foreign object trapped in the valve body. If it is ice, it will disappear when warmed up, soclose the manual valve and let it warm up. Contact the staff.
2-2. Electrical failure［Solution］ Try turning off the device.
Solenoid valves are designed to close when there is no electrical supply.
If it still does not close, there is a possibility that a foreign object is trapped in the valve body.
Please contact our staff.