型号: | HPM010 |
产地: | 美国 |
品牌: | |
评分: |
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The Proven High Pressure Freezing Machine
全球装机最多的高压冷冻装置
With over 100 installations world-wide, and more than 400 scientific publications to its credit, the HPM-010 is not only the pioneer of HP freezing, but the instrument of choice which allows freezing of aqueous samples up to 200µm thickness without visible ice crystal damage and without the use of cryoprotectants.
Features
Features / Benefits
Applications
The High Pressure Freezing Method
Excellent freezing of the specimens intended for examination in the electron
microscope is one of the most important prerequisites for achieving
reproducible results from the various subsequent cryopreparation methods.
The conventional freezing methods in use are plunge freezing, jet spray and
cold block (slamming) cryo fixation. However, due to the poor heat
conductance of water, these methods can only satisfactorily freeze specimens
measuring up to between 10 and 20µm.
Thicker specimens (such as tissue samples) could only be frozen in the past, if
a cryoprotectant was added to lower the freezing point of the water in the
specimen. The disadvantage of chemical cryoprotectants is that they often
affect certain cell structures, causing different types of undesirable artefacts.
By using the high pressure freezing method developed by Prof. Moor (ETH
Zurich) these artefacts can be eliminated. The high pressure method is based
on an entirely physical phenomenon that lowers the freezing point of water.
This method functions as follows: At 2,100 bar the melting point of water
drops from 0C to -22C. Under normal atmospheric conditions homogeneous
nucleation (supercooling) begins at -40C. Under high pressure this nucleation
doesn’t begin until the water has reached -90C (see H2O Phase Diagram).
At 2,100 bar water is 1,500 times more viscous than at atmospheric pressure, which drastically reduces the nucleation and thus the crystal growth rate. This means that the extremely high freezing rate (min. 10,000C/s required for satisfactory freezing by the methods previously mentioned) is not necessary with the high pressure method. The high pressure method allows specimens up to 0.2mm thickness with a total volume of approx. 1mm3 to be vitrified or up to 0.5mm thickness to be adequately frozen at a low freezing rate of 200C/s without requiring the addition of cryoprotectants.
Supplied complete with the following:
Specifications:
Working Data
Working pressure 2300 – 2600 bar
Maximum pressure 2800 bar
Duration of working pressure, at least 500 ms
Cooling time from 0C to -50C
(measured between 3 mm copper disc) 10 ms
Specimen Dimensions
Sample size, up to max. of 200µm thickness and 2mm diameter
Connection Data
Voltages, frequencies 3 x 380/220 V, 50 Hz or 3 x 208 V, 60 Hz
Power input, approx. 3kVA
Compressed air (5 bar) G 1/4” outer thread
LN2 (1 bar excess pressure) G 1/4” outer thread
Heating water (rubber hose) Ø 7/14mm
Operational Data
Hydraulic oil reservoir 40 liters
Hydraulic oil bias pressure 140 – 250 bar
LN2 Dewar (in system) 7 liters
LN2 consumption 10 – 20liters/hour
Initial system cooling, approx. 15 min.
Max. processing sequence, approx. 40 shots/hour
lsopropyl alcohol reservoir, approx. 0.5liters
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