Our autonomous cooling systems are designed for use in an instrumentation environment (e.g. scientific instruments) and/or in processes that require perfect control over the "cold" required.

Liquid Nitrogen (LN2) is used as the cooling medium and is taken from a storage vessel by a static pump and delivered through a fill line to the application in a micro dosing way.

One may view our technique as a cold generator with a temperature range from ambient to -196°C and with a controllable capacity. This capacity (= flow) can be adjusted by hand directly on the pump or by remote signals.

The system is designed to overcome the drawbacks of LN2 under pressure in which a solenoid valve is used to switch the supply ON / OFF. Our system instead delivers LN2 like tea out of a teapot: without any pressure.

Below is an overall view of a complete system and a detailed picture of a pump.

The picture on the left shows a complete system with sensor plugged in and "naked" cryo hose, the small vessel on the floor represents an application which needs to be cooled or filled; on the right is a backview of the pump.

sensor(s) included with each pump are 2 mini sensors of 2.30 mtr the actual Pt 100 sensor is in the tip of a 2mm diam. blue Teflon hose please note that this small diameter allows for the sensor to be slipped inside almost any application the sensor hose is surrounded by a black ribbed protection hose which limits knicks and bending the protection hose can be easily cut to a desired length   pump this is the actual pump which is mounted on a pressure less Dewar of 35 L. Dewars light weight Aluminum Dewars, height listed is for Dewar only 35L (standard) height: 591mm overall diam.: 480mm OD weight empty / full : 13 / 41.5 kg 50L (optional) height: 675mm overall diam.: 500mm OD weight empty / full : 17 / 57.5 kg 100L (optional) height: 1035mm overall diam.: 500mm OD weight empty / full : 32 / 113kg fill line a fill line with low thermal mass brings the LN2 to the application note the absence of a cryo valve! this implies the highest possible efficiency as there are no losses due to cooling of a bulky cryovalve or a metal hose the fill line on the left picture is shown without it's usual thermal isolation, so you can see that the actual cryo tubing is a Teflon hose of appr. 6mm OD a fill line of 1.80 mtr with all mounting hardware as shown below is included with each system safety valve although the system normally works with a pressure of less than 100mBar, there is a mechanical safety valve included it consists of a spring loaded Teflon coated disc, built into the knob you see after removing the knob you can take the cap away and get access to the multi position switch to set the pump into the required working mode connector all power + signal lines a grouped onto a 25D connector for connection to a PC the standard pump cable has a special connector incorporated (note * small connector on cable) just simply plug in the mating PC cable both 25D and PC cable are included with each pump sensor connections note that there are 2 sensor connections, so for e.g. a 2-point level control you plug both sensors into the pump body for e.g. a sub-zero temperature application only 1 sensor needs to be plugged in with each system 2 sensors are included flow setting with this numbered thumbwheel you set the flowrate when flow is set otherwise (e.g. by a remote signal) the setting of this potentiometer on the pump is the maximum flow allowed temperature setting with this potentiometer you set the desired temperature (if it is a #910 or #915 system) this setting can also be done by remote signals e.g. RS232 trolley the Dewar can be easily moved around with a trolley note that great attention is payed to minimise rattle when the vessel is transported outdoors all trolley / vessel contact is rubber cushioned the 5 wheels are suitable for outdoor transport (75mm diam) floorstand when the Dewar is being refilled and there is not a 2nd one available, the pump must be "parked" somewhere for that purpose a floorstand is optionally available power supply a special transformer is used as power supply and included with each system the transformer is fully encapsulated and needs no attention. System connection is by connector there are 2 versions available: 230V input 50/60 Hz, grounded by mains plug 115V input 50/60 Hz, mains plug to be supplied and mounted by user     MOVE YOUR CURSOR OVER AN ITEM OF INTEREST TO GET DETAILED INFO

Presently there are more models to choose from:

• #905, for level controlled applications   (working mode 1 to 6)

• #910,  all #905 functions +   for temperature controlled applications  (mode 1 to C)

• #915,  all #910 functions +   remote PCcontrol and history writing  (mode 1 to F)

• #600 serie,  specific systems for fixed applications

• #800,  which deliver gold gas only and no liquid *, functions like #900 serie

• adapted versions for industrial use*

All models look the same from the outside and can be internally set in different modes for the application on hand.

All models can be connected to a PC in order to display the status of the system. The software + hardware needed to do this is included with each pump.

GENERAL

In these systems a pressure less storage Dewar is used as a reservoir for LN2. On the Dewar a static pump is mounted. Inside the housing of the pump a µ-processor is used to control the various actions, depending upon the mode selected. The selection of a particular mode is made by a 16-position switch, also located inside the pump housing.

By controlling the pressure at time of liquid transport, the flow is controlled and thus any temperature between ambient and -196°C can be realized.

Any model will work without modifications as:

• autonomous stand alone unit
• direct remote controlled unit (controlled by your existing PID controller, PLC, computer with A/D conversion card, etc.)
• will operate on any voltage between 12-24 V, AC or DC
• computer controlled unit (#915 only)
• a system that looks, behaves and works like an instrument with almost no installation time required

Thanks to our static pump design there is:

• no need for a pressurized supply of LN2
• no need for a cryogenic solenoid valve
• no need for additional control instruments.

Any pump can communicate with a PC. Both the driver software and the adapter cable are included with each pump. The driver software is installed on your computer and communicates with the pump, like e.g. a printer driver with a printer. The adapter cable plugs directly into your PC and into the pump.

To display sensor temperatures, vessel pressure, status of LED's on pump etc. monitor software is included with any pump. This software is self installing and you only have to insert the CDrom that comes with the system and works under Windows '98 - 2000 - ME - NT - Vista - W7.

The screen adapts itself to the switch position set within the pump. Later on this page you can see all possibilities.

For display and controlling or e.g. history writing one needs a #915 pump, which has a RS232 line on board.

In addition to the Monitor software a UTILS-diskette is included with a 915-pump. Here you will find a software datarecorder (ready to use) and 2 sample programs to show what can be done (Freeze curve + system graphics).

ELUCIDATION

Over the years we encountered various applications for LN2 cooling and came to realize that cooling applications can generally be viewed at as being one of only 2 categories:

1- the ones that require a certain level of LN2

2- the ones that require a certain subzero temperature

This brought us to the idea to group all possible applications. Within a group we made the specific application a matter of putting a switch in the right position. So the difference between e.g. a 1-point level control and e.g. maintaining a certain sub-zero temperature for our system is only another switch position.

ad 1. Level controlled applications are grouped into a #905 pump and include:

• filling cold traps in vacuum systems
• filling biological storage vessels
• filling various small vessels one after the other at the press of a button
• filling actions at timer set intervals
• maintaining a certain level around 1 sensor
• maintaining a level between 2 sensors

In this kind of applications a system is used to transfer liquid from the storage vessel to the application at a given rate, until a sensor or other signal (e.g. switch or timer) stops the flow. This implies "on-off" control of the liquid flow, albeit that the flow can be extremely gentle if necessary.

ad 2. Temperature controlled applications are grouped into a #910 pump and include:

• thermal analysis systems
• computer controlled freezing
• gas chromatography
• temperature stages in microscopes
• subzero temperature control systems
• stopping chemical reactions
• cooling of targets, IR cells, cuvettes etc.
• back-up unit for deep freezers

In these applications a system is used in a micro-dosing way to bring just enough "cold" to the application as is needed, more at first to achieve the required subzero temperature and later less to maintain the temperature. This implies flow control in an analog fashion of "more-less" based on temperature measurement.

Each system is designed to be truly universal. It's various built-in modes of operation is of paramount importance for OEM and research applications as one system covers almost all possible needs for cooling, without the need for additional valves, control instruments etc. This means that standardisation within the facility is no longer wishful thinking, despite the various applications.

For any system a host of control possibilities are foreseen. This makes it possible to control a system from existing analytical equipment, PLC's, simple switches, computers etc. almost without any adaptations.

SYSTEM DETAILS

The standard system includes a pressure less storage Dewar of 35-Liter. Larger vessels are possible, smaller too.

On the Dewar a static pump is mounted using a NW50KF flange. A dipstick protecting a.o. rise pipe and "Dewar nearly empty" level sensor, protrudes from flange to (almost) bottom of the storage vessel.

The pump action is caused by generating a slight and controlled over pressure in the Dewar (in the mbar range), thus driving the liquid through the rise pipe and through the fill hose to the application.

As mentioned earlier, a system works autonomously and you do not need a PC at all. However for a good understanding of what is going on a PC-screen is very informative. Especially the monitor program gives you perfect insight on how things are accomplished.

Make your choice for a detailed information about:

• Monitor program (included with every pump)

• Datarecorder (included with #915 only)

• Sample programs (included with #915 only)

• Setup example for filling small dewars

• Setup example for temperature control

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