DEWAR flasks

Dewar Flasks Made of Glass

Construction and Function of Dewar Flasks

Dewar flasks are double walled vacuum insulated flasks made of glass or metal, which have the task to thermally insulate a therein-stored product (LN2; CO2 etc.) against the ambient temperature. Dewar flasks consist of an inner and an outer recipient, whichare connected on top at the filling port. The space between the inner and the outer flask is vacuum insulated, to stop the heat contact between the product stored in the Dewar flask and the ambient temperature (contact warmth). Additionally, Dewar flasks made of glass have a silver coating in the vacuum space, in order to minimise the warmth radiation. The best possible insulation could be received by reducing the contact warmth and the radiation warmth.

 

Admissible Operation Conditions for Standard Glass Flasks

Temperature range Dewar -200°C to +200 °C Temperature range other components -10°C to +80 °C Pressure range depressurised

Standard -Dewar flasks are not appropriate for the use of liquid and gaseous helium. Special design is available on request.

Standards and Guidelines

All of the EMCLAB glassware are manufactured considering —Guideline of pressure devices", directive 97/23 EC and DIN 12492 "Equipment with vacuum insulation". Under the condition that there are any standards for joint parts such as spherical ground joints or conical ground joints, those will be utilised (e.g. DIN 12242-1 and DIN 12244-1).

Verifications

Each of the EMCLAB products is subject to individual verification and identification, as well as the documentation of all manufacturing data.

Testing device for measurement of the LN2 evaporation rate Helium leak test device Ultrasonic wall thickness measuring instrument Vacuum measuring and calibration device Temperature measuring and calibration device Water and compressed-air testing device for reaction vessels Temperature testing device for columns

For the evaporation rates of Dewar flasks mentioned in the catalogue, the flasks were covered with the appertaining lid respective plug, and were verified with the coolants (liquid nitrogen, or dry ice) mentioned in the catalogue. The figures (evaporation rate) are stated in the catalogue in L/h (litres per hour) or as holding time in hours.

Material - Glass

All the glassware from EMCLAB are made of borosilicate glass 3.3 DIN/ISO 3585. The glass has the following characteristics:

Chemical characteristics hydrolytic resistance : according to DIN-ISO 719 (98°C) acid resistance : according to DIN12116, acid class 1 acid resistance : according to DIN-ISO 1776 alkaline resistance : according to DIN 52322 alkaline resistance class : according to DIN 52322-A2 :according to ISO 695-A2

Optical characteristics spectrum region, where the : 310-200 mm absorption is negligible low

Physical characteristics linear expansion factor : 3,3 x 10-6 1/K (at 20°C-300°C)

density : 2,23 g/cm3
specific thermal capacity : 910 J/kg K
transformation temperature : 525 °C

Dewar Vessels cylindrical

Application

flexible applications in laboratory
cooling of small samples
storage: liquid nitrogen (LN2), dry ice (CO2), other coolantsas insulating flask

Advantages

high insulating ability, easy handling, made of Borosilicatglass 3.3, deliverable: fully silvered (standard), not silvered, silvered with viewing stripes, shortened

Versions

C: blue coated metal cover
G-C: blue coated metal cover incl. side grip

Dewar Vessels cylindrical
Art. No.DescriptionHolding time LN2 ca. [h]Evaporation rate LN2 ca. [L/d]
EMC-1025Dewar flask cylindrical 3 C, 500 ml300.35
EMC-1028Dewar flask cylindrical 6 C, 800 ml540.35
EMC-1064Dewar flask cylindrical 3 G-C with grip, 500 ml300.35
EMC-1066Dewar flask cylindrical 6 G-C with grip, 800 ml540.35
EMC-1068Dewar flask cylindrical 9 G-C with grip, 1000 ml600.35
EMC-10211Dewar flask cylindrical 9 C, 1000 ml600.35
EMC-10217Dewar flask cylindrical 15 C, 1500 ml490.7
EMC-10612Dewar flask cylindrical 15 G-C with grip, 1500 ml 490.7
*LN2 Evaporation rate measured with plug; L/d Litre per day
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Dewar Vessels dish-shaped

Application

tempering of round bottom flasks
cooling of small samples
suitable as a hot or cold bath
suitable on magnetic stirrer

Advantages

easy handling, aluminium cover: antimagnetic, stainless
made of Borosilicatglass 3.3 fully silvered

Dewar Vessels dish-shaped
Art. No.DescriptionFor round bottom flask Ø a. [mm]With content max. [ml]
EMC-1192Dewar flask dish-shaped SCH 9 CAL, 120 ml64100
EMC-1194Dewar flask dish-shaped SCH 18 CAL, 400 ml85250
EMC-1195Dewar flask dish-shaped SCH 20 CAL, 680 ml105500
EMC-1196Dewar flask dish-shaped SCH 30 CAL, 1600 ml131 / 1661000 / 2000
EMC-1197Dewar flask dish-shaped SCH 31 CAL, 3000 ml1853000
EMC-1198Dewar flask dish-shaped SCH 33 CAL, 5800 ml2366000
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Dewar Vessels carrying

Application

storage and transport of temperature-sensitive goods e.g. dry ice (CO2)
flexible applications in laboratory
cooling of small samples
as high quality insulating flask
when storing liquid nitrogen (LN2) a hole (Ø ca. 2 mm) in centre of the lid is necessary

Advantages

robust design, made of Borosilicatglass 3.3, incl. insulated lid held by two spring clips, incl. handle made of aluminium

Versions

B: blue coated metal cover
BE: stainless steel cover

Dewar Vessels carrying flasks
Art. No.DescriptionHolding time LN2 ca. [h]Evaporation rate LN2 ca. [L/d]
EMC-1211Dewar carrying flask 26 B, 1000 ml171.2
EMC-1212Dewar carrying flask 27 B, 2000 ml231.9
EMC-1213Dewar carrying flask 28 B, 3000 ml401.6
EMC-1214Dewar carrying flask 29 B, 4000 ml711.4
EMC-1221Dewar carrying flask 26 BE, 1000 ml171.2
EMC-1222Dewar carrying flask 27 BE, 2000 ml231.9
EMC-1223Dewar carrying flask 28 BE, 3000 ml401.6
EMC-1224Dewar carrying flask 29 BE, 4000 ml711.4
*LN2 Evaporation rate measured with plug; L/d Litre per day
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Dewar Vessels large insulating

Application

storage and transport of temperature sensitive goods e.g. dry ice (CO2)
suitable as insulating flask

Advantages

robust design, large opening, made of Borosilicatglass 3.3, insulated lid (incl. grip), handle or two grips
deliverable: fully silvered (standard), silvered with viewing stripes, incl. quick release clamp, shortened

Version

C: blue coated metal cover

Dewar Vessels large insulating
Art. No.DescriptionEvaporation rate CO2 ca. [kg/d]
EMC-1241Dewar flask large insulating 30 C, 7 l0.45
EMC-1242Dewar flask large insulating 31 C, 10 l0.4
EMC-1243Dewar flask large insulating 32 C, 14 l0.4
EMC-1248Dewar flask large insulating 30/4 C, 4 l0.45
EMC-1249Dewar flask large insulating 30/7 C, 7 l0.4
*CO2 Evaporation rate measured with insulated disc; kg/d kilogram per day
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Dewar Vessels spherical

Application

storage and transport of liquid nitrogen (LN2)

Advantages

low evaporation rate, good tipping stability, made of Borosilicatglass 3.3, incl. loose lied lid, incl. handle, deliverable: fully silvered (standard), silvered with viewing stripes

Version

AL: aluminium cover, brushed

Dewar Vessels spherical
Art. No.DescriptionHolding time LN2 ca. [days]Evaporation rate LN2 ca. [L/d]
EMC-1291Dewar flask spherical 21 AL, 1000 ml50.2
EMC-1292Dewar flask spherical 22 AL, 3000 ml70.4
EMC-1293Dewar flask spherical 23 AL, 5000 ml120.4
EMC-1294Dewar flask spherical 24 AL, 10 l160.6
*LN 2 evaporation rate measured with plug; L/d Litre per day
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Dewar Vessels stainless steel

Application

flexible applications in laboratory
cooling of small samples
storage and transport of: liquid nitrogen (LN2), dry ice (CO2), other coolants
suitable as insulating flask

Advantages

good resistance to breaking, easy handling, made of stainless steel, side grip and carrying handle (except DSS 500/GSS 500: no carrying handle)

Dewar Vessels stainless steel
Art. No.DescriptionHolding time LN2 ca. [h]Evaporation rate LN2 ca. [L/d]
EMC-2100Dewar flask stainless steel DSS 500, 500 ml121,0
EMC-2101Dewar flask stainless steel DSS 1000, 1000 ml210,9
EMC-2102Dewar flask stainless steel DSS 1000 W, 1000 ml151,6
EMC-2103Dewar flask stainless steel DSS 2000, 2000 ml421,1
EMC-2104Dewar flask stainless steel DSS 3000, 3000 ml223,1
EMC-2105Dewar flask stainless steel DSS 6000, 6000 ml492,9
EMC-2304Dewar flask stainless steel with grip GSS 500, 500 ml121,0
EMC-2300Dewar flask stainless steel with grip GSS 1000, 1000 ml210,9
EMC-2301Dewar flask stainless steel with grip GSS 1000 W, 1000 ml151,6
EMC-2302Dewar flask stainless steel with grip GSS 3000, 3000 ml421,1
EMC-2303Dewar flask stainless steel with grip GSS 2000, 2000 ml223,1
EMC-2305Dewar flask stainless steel with grip GSS 6000, 6000 ml492,9
*LN2 Evaporation rate measured with plug; L/d Litre per day
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Tempering Beakers made of glass

Application

tempering of liquids
the tempering medium is pumped round the double walled casing with the aid of a thermostat

Advantages

made of Borosilicatglass 3.3, operating temperature max. 300 °C for Type T and  max. 120 °C for Type T-GL,
coolant ram pressure max. 0,5 bar, high thermal resistance, very good chemical resistance, transparency, deliverable various special jacket joints, special dimensions

Versions

T: with hose connectors
T-GL: with screw hose connectors

Tempering Beakers made of glass
Art. No.Description
EMC-1351Tempering glass beaker T 250, 250 ml
EMC-1352Tempering glass beaker T 600, 600 ml
EMC-1353Tempering glass beaker T 2000, 2000 ml
EMC-1355Tempering glass beaker T-GL 250, 250 ml
EMC-1356Tempering glass beaker T-GL 600, 600 ml
EMC-1357Tempering glass beaker T-GL 2000, 2000 ml
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Tempering Beakers stainless steel

Application

tempering of liquids
the tempering medium is pumped round the double walled casing with the aid of a thermostat.

Advantages

made of stainless steel, good resistance to breaking, stainless, operating temperature max. 200 °C (further temperatures by request), coolant ram pressure max. 0,5 bar, olive welded

Tempering Beakers made of stainless steel
Art. No.Description
EMC-2200Tempering stainless steel beaker TSS 1000, 1000 ml
EMC-2201Tempering stainless steel beaker TSS 2000, 2000 ml
EMC-2202Tempering stainless steel beaker TSS 3000, 3000 ml
EMC-2203Tempering stainless steel beaker TSS 6000, 6000 ml
EMC-2204Tempering stainless steel beaker TSS 500, 500 ml
EMC-2205Tempering stainless steel beaker TSS1000W, 1000 ml
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Dewar Vessels with cold trap

Construction, Operation And Principles

Cold traps are used in conjunction with vacuum pumps to collect condensation produced from humidity or solvents and these cold traps can be used for many different tasks. The most common application is collecting condensation produced from humidity or solvents from rotating discs, vacuum pumps or high vacuum systems that use oil diffusion or turbo-molecular pumps. In this case a common coolant such as liquid nitrogen (LN2) or dry-ice (CO2) with acetone is normally used.

Cold traps can be manufacturer from glass or metal. The use of glass is advantageous in the chemical sector and when producing condensation from solvents, due to its resistance to chemicals. The cold traps listed in our catalogue are produced solely from 3.3-type borosilicate glass, in compliance with DIN/ISO (DURAN made by Schott). The mechanically design takes into account the wall thickness for use under vacuum.

Cold Traps – Different Versions

Simple cold traps, which are also known as cold finger condensers, are used in standard applications in conjunction with vacuum pumps and the condensation is forced out of the humidity or solvents used in the chemical applications. The cold trap is used to protect the vacuum pump in this case and the speciality of this type of construction is that the user does not need to use a stand to hold the cold trap. The cold trap has a rim, which is hung inside the Dewar-flask's support ring. The cold trap can be changed very quickly without any problems arising.

Cold Traps Fitted With A Spout

An upgraded version is a cold trap fitted with a spout. These cold traps are constructed in the same way as standard cold traps but have a GL 32 glass thread together with a screw-on cap, which is the actual spout. This spout enables the condensation to be simply poured out of the cold trap and the cold trap is also simple and easy to clean.

Dewar Vessels with cold trap
Art. No.DescriptionCondensate Capacity [ml]Coolant capacity [ml]
EMC-1731Cold trap KF 29-K, spherical joint, encl. Dewar1501000
EMC-1735Cold trap KF 29-OK, spherical joint, encl. Dewar1501000
EMC-1740Cold trap KF 29-GL,screw thread GL 18, encl. Dewar1501000
EMC-17360Cold trap KFL 29-K, spherical joint, encl. Dewar2502000
EMC-17361Cold trap KFL 29-OK, spherical joint, encl. Dewar2502000
EMC-17362Cold trap KFL 29-GL,screw thread GL18, encl. Dewar2502000
EMC-17370Cold trap KF 29-K-A, spherical joint, encl. Dewar1501000
EMC-17371Cold trap KF 29-OK-A, spherical joint, encl. Dewar1501000
EMC-17372Cold trap KF 29-GLA,screw thread GL18, encl. Dewar1501000
EMC-17380Cold trap KFL 29-K-A, spherical joint, encl. Dewar2502000
EMC-17381Cold trap KFL 29-OK-A, spherical joint,encl. Dewar2502000
EMC-17382Cold trap KFL29-GLA,screw thread GL18, encl. Dewar2502000
*S29 spherical joint; GL18 glass screwthread with PTFE olive; O spherical joint S29 with O-ring seal
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