( covering model #905, #910 and #915 )
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video pumpflow on 30 mBar, in 10 seconds |
| picture shows pump on 35 liter dewar total system height 79 cm, diam. 48cm(excl. wheels) pump can be used on other type dewars as long as the dewar has a NW50 flange (new window) |
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Norhof manufactures crygenic cooling systems in which Liquid Nitrogen (LN2) is used as the cooling medium. LN2 is transferred from the dewar to your application 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 liquid nitrogen, with an adjustable flow, possible to regulate from some drops, up to 1 Liter/minute.
The cryogenic transfer flow is variable and can be optimized to the application.
Flow control is on the system itself or by remote signals. With one and the same system the transfer flow range is from
The majority of our systems find use in the field of scientific instruments, physical laboratories, research centers etc. where precise control over subzero temperatures is required or where a LN2 transfer flow of app. 1 L/min is sufficient. Industrial systems with 15 L/min based on the same principle are also available.
Use of this system is for example for:
| WORKING PRINCIPLE The pressure above the liquid nitrogen level inside the dewar is carefully controlled and therefor the flow. With only 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. |
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In the Norhof LN2 cooling systems the Liquid Nitrogen is stored in pressure less cryogenic Dewars. When LN2 transfer is required, a small overpressure is generated by a micro processor controlled heater element in the LN2, and liquid nitrogen flows out of the system like water from a tap, without spilling, noise, vibrations etc.
The advantages are numerous:
• 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
Liquid nitrogen comes out of insulated tubing without making contact to warm metallic parts
• there is no additional control unit required
which adds to a clean and elegant setup
• the pump is software driven and many control modes are already built-in
like 1-point level control, 2-point level control, timer based control, subzero temperature control, flow control by 0-5V input, control by RS232 line, etc.
• level or temperature sensors are plugged directly into the pump housing
and not into a separate control box
• the system can deliver LN2 liquid with a flow optimized for the application
and can inject LN2 without noise, vibration, excessive waste, etc.
• the variable flow feature makes subzero temperature control extremely easy
see under SOFTWARE > sample drivers > freeze curve (model #910 and #915)
• the system is foreseen to be connected to a PC
great for trouble shooting, history writing or remote control
• P.E.D. 92/23/EC (Pressure European Directive) for pressurized vessels does not apply for this liquid nitrogen system
The maximum possible pressure is 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 adjustable from 0.01mBar to 270 mBar (by potmeter on pump) == dripping upto ab. 0.5 Liter/minute (with 2 m. 6.25mm fill line)
Maximum working pressure < 300 mBar Reaction time ab. 2 minutes for cooling down the fill line (with 2 meters fill line) Power connection 115V / 230V AC with supplied power supply or 12-24 Volt AC/DC Power consumption average 5 Watts, during pumping 50 watts Storage container volume 25 Liter (on request) 35 Liter (standard) 50 Liter (option) Outside dimensions (round) 395 480 500 mm Height dimensions 884 791 875 mm Weight (empty,full) 10 / 31 13 / 41,5 17 / 51,5 kg Standard fill line 6.25 mm OD, 4 mm ID PTFE tube, with 32mm foam insulation System includes Dewar, pump, fill line 2.00 m, phase separator, power supply, cables, 2 level sensors, PC software. Working modes
- #905, working mode 1 to 7 for level control
- #910, working mode 1 to D including temperature control
- #915, working mode 1 to F including full RS232 steering
External steering
- #905, 5 volt signals for ON, OFF , RS232 signals for ON, OFF
- #910 and #915, more signals to steer, depending on mode
PC software
- Monitor software, to monitor pump behavior, and for some working modes to adjust some parameters.
- For #915, + pump utils software for RS232 control
Alarms/warning acoustical/ visual / mechanical Dewar empty, dewar 5 liters LN2 left, broken sensor(s), frozen alarm, mechanical overpressure protection valve. Options Transport trolley 5 wheels (12 cm height) Stand for pump (when dewar is refilled)
Custom build adaptor to fixate sensor(s) on application
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