Laboratory Products
Exploring safe and intelligent multi-application liquid nitrogen cooling via auto-fi ll technology
Mr E.G.M. Bisschop The handling of Liquid Nitrogen (LN2 ) is not easy and can be extremely hazardous. Scientists are unable to avoid using LN2 cooling power of the liquid. A system enabling the use of cryogenic cooling without the risk of coming into contact with LN2 The LN2 used as the cooling medium. LN2
microdosing system is a cryogenic cooling system in which Liquid Nitrogen (LN2 is transferred from the Dewar to the desired application.
The Norhof LN2 cooling systems stores the Liquid Nitrogen in pressureless cryogenic Dewars. When a LN2 the LN2
transfer is required, a micro processor controlled heater element in generates a small overpressure and liquid nitrogen fl ows out of the system like
water from a tap, without spilling, noise and vibrations. The cryogenic transfer fl ow is variable and can be optimised to the application.
These autonomous cooling systems are designed for use in scientifi c instrumentation environments and/or in processes that require perfect control over the temperature required. LN2
solenoid valve is used to switch the supply ON/OFF. The system instead delivers a pressure less fl ow of LN2
pump and delivered through a fi ll line to the application in a micro dosing way. The system is designed to overcome the drawbacks of LN2
.
The pump is software driven and many control modes are already built-in; subzero temperature control, fl ow control by 0-5V input, control by RS232 line, etc. Figure 1 shows a software screenshot. The temperature sensor(s) are plugged directly into the pump housing; and not into a separate control box.
under pressure in which a is used as the cooling medium and is taken from a storage vessel by a static ) is
as there are applications requiring the is therefore desirable.
monitoring and data logging or remote control and connects to a PC quickly and easily. The P.E.D. 99/36/EC (Pressure European Directive) for pressurised vessels does not apply for this system.
As the maximum possible pressure is lower than 300m bar the system can be safely used inside the lab, near your working place.
Temperature controlled applications: • thermal analysis systems • computer controlled freezing • gas chromatography • temperature stages in microscopes • sub-zero temperature control systems • stopping chemical reactions • cooling of FTIR detectors
• cooling of targets, IR cells, cuvettes etc.
In these applications a system is used in a micro-dosing way to bring just enough cooling to the application as is needed, more at fi rst to achieve the required sub-zero temperature and later less to maintain the temperature. This means that fl ow control in an analogue fashion of ‘more-less’ based on temperature measurement is necessary. Each system is designed to be truly universal. 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 or control instruments. This means that standardisation within the facility is no longer wishful thinking, despite the varied application demands.
For any system, a host of control possibilities are prerequsites so that users can control it from existing analytical equipment, PLC’s, simple switches, computers etc. almost without any adaptations.
Example 1: FTIR detector
Dewar to cool the detector down. The LN2 microdosing system provides a universal
Figure 1: Screenshot Temperature Control Software Advantages:
fl ow optimised for the application without noise, vibration and excessive waste. A variable fl ow feature makes sub-zero temperature control extremely easy. The system is perfect for
unnecessary heat input and noise. The set up is clean and ergonomic as no additional control unit is required. The software controlled pump can deliver N2
The advantages of the system described is that as a LN2
valve is not required there is no cold liquid with a
The response time and sensitivity of photonic detectors can be much higher if the detector is cooled to decrease the thermal noise. Normally you have to spill LN2
in a small
automatic fi lling system for FTIR detectors. It allows long-term measurements and the FTIR
spectrometer is able to run overnight. The system is fully safe to use inside the laboratory. It allows an easy setup to most FTIR detectors. Figure 2 shows a FTIR detector setup.
Figure 2: FTIR detector setup
The pressure above the liquid level inside the Dewar is built by heating a small amount of liquid in the bottom of the Dewar.
INTERNATIONAL LABMATE - JULY 2019
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