NORHOF LN2 Dispensing System   model #405

Low cost hand controlled Liquid Nitrogen Dispensing system

Are you still poring LN2 into small vessels by hand?

• Safe filling of small vessels
• Hand controlled administration of smaller amounts of LN2, for filling small dewars or samples
• Low flow, starting by pressing on pumphead.
• Pressure-less flowing LN2, without spilling, noise, vibrations etc. 

picture shows pump mounted on a 35 Liter dewar possible dewars are 25, 35 or 50 Liter pump can be used on other type dewars as long as the dewar has a NW50 flange	total system height 60 cm

Norhof manufactures cooling systems in which Liquid Nitrogen (LN2) is used as the cooling medium. LN2 is supplied without any pressure and filling an application is like a teapot filling a teacup.

You may compare our liquid nitrogen dispenser system with a water tap , but instead of giving water, it gives LN2, starting  with some drops, up to 1 Liter/minute.

Liquid Nitrogen (LN2)

The reservoir dewar can safely stand next to your working place. When you need a small amount of LN2, the system is ready to supply by only pressing on the pumphead. By pressing on the pumphead, the system switches ON and starts building a small over pressure, forcing the liquid gently to rise into the fill line, and fall into your little dewar, or other small LN2 container.

After your pressure on the pumphead is released, the system shuts off automatically, and the flow stops.

Usage

The majority of this system find use in the field of scientific instruments, physical laboratories, research centers etc. where small amounts of liquid nitrogen is needed every day for experiments, and where it is handy to have your supply next to your working place, instead of walking all the way to a fill station and handle big pressure tanks for filling just a tea cup of LN2.

Use of this system is for example for:

• hand-controlled filling of small dewars
• hand-controlled cooling of small objects
• hand-controlled freezing of small samples
• hand-controlled filling of Dry Shippers
• hand-controlled washing of Xtals
• hand-controlled cooling of small chemical reactions

*For automatic administration we have the #900 serie of microdosing pumps, see the left column

WORKING PRINCIPLE The pressure above the liquid level inside the dewar is built by heating a small amount of liquid in the bottom of the dewar.  With only up to 100 mBar of overpressure, the liquid will gentle rise out of the rise pipe and fall into the fill hose. Because we evaporate some LN2 to build pressure, there is no adding of ice inside the dewar, such as with manual systems which use air from the environment.

*#900 pump model shown on this picture

In the Norhof LN2 cooling systems Liquid Nitrogen is stored in pressure less Dewars. When LN2 is required, a small overpressure is generated by a small heater element in the LN2, and liquid flows out of the system like water from a tap, without spilling, noise, vibrations etc.

The advantages are numerous:

• the system can deliver LN2 liquid just with a press on the pump head

this means that the system is ready for use 24 hours a day.

• the system delivers LN2 without any pressure

this means without noise, vibration, excessive waste, etc.

• there is no external LN2 valve required

that implies no unnecessary heat input which spoils a lot of LN2

• there is no internal LN2 valve in the pump

LN2 comes out of insulated tubing without making contact to warm metallic parts, so very fast

• there is a very low thermal masse to cool down in the pump

LN2 comes out within 10 to 40 seconds, depending on the level in the dewar.

Filling efficiency is better than 90%, due to very less loss for cooling down pump parts.

• there is a very low thermal connection to the ambient temperature

This means that the system is extremely economic in stand-by. Typical usage less than 0,5 Liter / day

• P.E.D. 92/23/EC (Pressure European Directive) for pressurized vessels does not apply for this system

The maximum possible pressure is lower than 300mBar.Therefore this system is allowed to be used inside the lab, near your working place, without danger.

Technical Specifications

Static evaporation rate	< 0,5 liters per day
Flow rate	Dripping up to 1 Liter/minute (not adjustable)
Maximum working pressure	< 300 mBar
Reaction time	10-40 seconds (depending on level in dewar)
Power connection	115V / 230V AC with supplied power supply or 12 Volt AC/DC
Power consumption	average 10 Watts, during pumping 50 watts
Storage container volume	25 Liter(on request)	35 Liter	50 Liter
Outside dimensions (round)	395	480	500 mm
Height dimensions	736	643	727 mm
Weight (empty,full)	10 / 31	13 / 41,5	17 / 51,5 kg
Options	Transport trolley 5 wheels (12 cm height)

April 2008

 

 

for more models use links in left column