Flask (German) Kolben) - a glass vessel with a round or flat bottom, usually with a narrow long neck. A type of technical vessels used in chemical laboratories.

Flasks are also called cylinders of electric vacuum and gas-discharge lamps. Flasks are used in laboratories as reaction vessels. There are also special volumetric flasks for preparing analytical solutions with high precision.

To heat flasks in laboratories and chemical industries, specialized and universal mantle heaters are used.

Pear-shaped flasks type Gr

Purpose and scope of application of the pear-shaped flask:

Pear-shaped flask type Gr is intended for evaporation, filtering, distillation, distillation, synthesis and distillation of chemical substances for laboratory purposes. The pear-shaped flask Gr has interchangeable cones. The pear-shaped flask Gr is made of chemically resistant glass of the TS group. Laboratory flasks type Gr are resistant to chemical solutions.

• H - Overall length of flask (mm)

Conical flasks type Kn

Purpose and scope of application of a conical flask type Kn

Conical flasks type Kn are intended for evaporation, filtering, distillation, distillation, synthesis and distillation of chemicals for laboratory purposes. Kn flask is pear-shaped. Made from chemically resistant glass of the TS group. Laboratory flasks type Kn are resistant to chemical solutions.

• H - Overall length of flask (mm)
• D - Diameter of the wide part of the bulb (mm)

Conical flasks with interchangeable cones, TS TU 14307481.014-95

Conical flasks with a cylindrical neck, TS GOST 25336-82

Conical flasks with a cylindrical neck, TS TU 14307481.014-95

Round-bottom flasks type KRN (Engler)

Purpose and scope of application of the Engler flask

The round flask is used for laboratory work related to the distillation of petroleum products. The Engler flask is made of chemically resistant glass of the TC group. Laboratory flasks type KRN are resistant to chemical solutions.

• H - Overall length of flask (mm)
• D - Diameter of the wide part of the bulb (mm)

Round-bottom flasks type K version 1 version 2

Purpose and scope of flask type K

The flask is intended for laboratory work and can be used as a receiver for distillation. Used for various syntheses and laboratory work. Type K flask is pear-shaped. Made from chemically resistant glass of the TS group. Laboratory flasks type K are resistant to chemical solutions.

• H - Overall length of flask (mm)
• D - Diameter of the wide part of the bulb (mm)

Round-bottom flasks with a cylindrical neck, TS GOST 25336-82

Round-bottom flasks with interchangeable cones, TS GOST 25336-82

* A round-bottomed flask with a capacity of 1000 ml is available only with interchangeable cones (version 1).
GOST 25336-82

Pointed-bottom flasks type O with interchangeable cone

Description and application of laboratory sharp-bottomed flasks type O:

Pointed-bottom flasks type O are used for filtering, distillation, distillation, distillation and synthesis of chemicals in laboratory conditions.

Flat-bottomed flasks type P

Purpose and scope of application of flat-bottomed flask type P:

Flat-bottomed flasks are used as a receiver for the distillation of various organic syntheses and laboratory work.
Flasks, type P, are made from chemically resistant glass of the TC group.

Laboratory flasks type P are resistant to chemical solutions.

• H - Overall length of flask (mm)
• D - Diameter of the wide part of the bulb (mm)

Flat-bottomed flask with interchangeable cone

Flat-bottomed flask with cylindrical neck

* Flat-bottomed flask type P with a capacity of 25 ml is produced only with a cylindrical neck (version 2) according to TU 3 of Ukraine 14307481.014-95.

Flasks with tube (Bunsen)

Purpose and scope of application of a Bunsen flask with a tube:

A Bunsen flask with a tube is used for vacuum filtration.

A Bunsen flask is made of glass and has a thick-walled conical shape.

The top of the flask has space for connection to a vacuum pump or vacuum line.

The flask with tube is intended for laboratory use.

It is made from chemically resistant glass of the TS group in two versions - with an interchangeable cone and a cylindrical neck. The nominal capacity in the designation and name of the flasks is conditional. Laboratory Bunsen flasks are resistant to chemical solutions.

• H - Overall length of flask (mm)
• D - Diameter of the wide part of the bulb (mm)

Flask with tube (Bunsen) with a cylindrical neck

Tube flask (Bunsen) with interchangeable cones

Kjeldahl type flasks

Purpose and scope of application of the Kjeldahl flask

Kjeldahl flasks are used as receivers for distillation, various organic syntheses, laboratory processes and Kjeldahl determination of nitrogen.

The Kjeldahl flask is pear-shaped.

Manufactured from chemically resistant glass of the TS group. Laboratory Kjeldahl flasks are resistant to chemical solutions.

• H - Overall length of flask (mm)
• D - Diameter of the wide part of the bulb (mm)

Kjeldahl flask with interchangeable cones

Kjeldahl flask with cylindrical neck

Kohlrausch flasks

Purpose and scope of application of the Kohlrausch flask:

Kohlrausch laboratory flasks are used to measure volume, settle liquids and determine the percentage of sugar in sugar beets.

Kohlrausch laboratory flasks are resistant to chemical solutions.

• H - Overall height of Kohlrausch flask (mm)
• D - Diameter of the wide part of the Kohlrausch flask (mm)

Volumetric flasks of 1st and 2nd accuracy class

Purpose and scope of application of the volumetric flask:

Volumetric flasks are used to store and measure a certain volume of liquid.

Volumetric flasks are round-pear-shaped measuring glass vessels with an elongated cylindrical neck.

• H - Bulb height (mm)
• D - Diameter of the wide part of the flask (mm) Options for designs of volumetric flasks.

Execution of volumetric flasks:

• Spanish 1 - Measuring flasks with one mark;
• Spanish 2 - Measuring flasks with one mark and a ground stopper;
• Spanish 2a - Measuring flasks with one mark and a plastic stopper;
• Spanish 3 - Measuring flasks with two marks;
• Spanish 4 - Measuring flasks with two marks and a ground stopper;
• Spanish 4a - Measuring flasks with two marks and a plastic stopper.

Volumetric flasks, 1st accuracy class GOST 1770-74

Measuring flasks, 2nd accuracy class GOST 1770-74

Laboratory glass VITLAB- This is glass made in Germany. But there is also laboratory glass Schott Duran, and don’t forget about the Czech manufacturer “Simax”, which produces glass of the highest quality.

Ukrainian laboratory glass is produced in Poltava, but despite this, it can easily be bought in Kyiv by calling our office of UKR-Khimiya LLC

Material from Wikipedia - the free encyclopedia

Bunsen flask, Also flask with tube, vacuum flask, in some countries also Buchner flask or Kitasaki flask- a flat-bottomed conical flask made of thick-walled glass with a tube (outlet). Bunsen flasks are mainly used for vacuum filtration. The creator is the German experimental chemist Robert Wilhelm Bunsen (1811-1899).

The Bunsen flask has different versions:

• A standard Bunsen flask is a thick-walled conical flask with a side outlet.
• A Bunsen flask with a lower tube, in which an additional tube is used to drain the filtrate while turning off the vacuum source.
• A Bunsen flask with a three-way stopcock, in which the filtrate can be drained without turning off the vacuum source.

Bunsen flasks are usually made from glass with a thickness of 3 mm to 8 mm. In the Russian Federation, Bunsen flasks are standardized as “flasks with a tube” according to GOST 25336 (for their production, heat-resistant glass of the TS grade according to GOST 21400 or Simaks ChSN ISO 3585 is usually used). The upper conical part, intended for installing a filter funnel, can be smooth or ground for an interchangeable cone in accordance with GOST 8682. Flasks can also be made of metal or plastic.

The Bunsen flask is used mainly for vacuum filtration, in which this flask serves as a collector for the filtrate. The Bunsen flask can be used for other purposes, for example, to produce gases in chemical reactions, and also as a safety vessel in vacuum processes.

Notes

Literature

• “Name” devices in the magazine “Chemistry”
• Stepin B.D. Laboratory experiment technique in chemistry: Textbook. manual for universities. M.: Chemistry, 1999. - 600 p.: ill.

Bunsen flask, Also flask with tube, vacuum flask, in some countries also Buchner flask or Kitasaki flask- a flat-bottomed conical flask made of thick-walled glass with a tube (outlet). Bunsen flasks are mainly used for vacuum filtration. The creator is the German experimental chemist Robert Wilhelm Bunsen (1811-1899).

The Bunsen flask has different versions:

• A standard Bunsen flask is a thick-walled conical flask with a side outlet.
• A Bunsen flask with a lower tube, in which an additional tube is used to drain the filtrate while turning off the vacuum source.
• A Bunsen flask with a three-way stopcock, in which the filtrate can be drained without turning off the vacuum source.

Bunsen flasks are usually made from glass with a thickness of 3 mm to 8 mm. In the Russian Federation, Bunsen flasks are standardized as “flasks with a tube” according to GOST 25336 (for their production, heat-resistant glass of the TS grade according to GOST 21400 or Simaks ChSN ISO 3585 is usually used). The upper conical part, intended for installing a filter funnel, can be smooth or ground for an interchangeable cone in accordance with GOST 8682. Flasks can also be made of metal or plastic.

The Bunsen flask is used mainly for vacuum filtration, in which this flask serves as a collector for the filtrate. The Bunsen flask can be used for other purposes, for example, to produce gases in chemical reactions, and also as a safety vessel in vacuum processes.

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Notes

Literature

• in the journal "Chemistry"
• Stepin B.D. Laboratory experiment technique in chemistry: Textbook. manual for universities. M.: Chemistry, 1999. - 600 p.: ill. ISBN 5-7245-0955-5

see also

An excerpt characterizing the Bunsen flask

Beakers are thin-walled cylinders of various capacities. They come in two types: with spouts and without spouts (Fig. 28). Just like other chemical glassware, glasses are made from both refractory and chemically resistant glass.

You cannot heat glasses made of ordinary glass over a naked flame - this will cause them to burst. Heating should be carried out only through an asbestos mesh or in a water or other bath.

In addition to chemical beakers, laboratories sometimes use thick-walled, so-called battery beakers. They also come in different sizes and capacities and are designed to operate without heating.

Flat-bottomed flasks (Fig. 29) come in a wide variety of capacities, ranging from 50 ml to several liters, with and without a polished neck. They are made from ordinary glass, as well as from quartz and special types of glass.

Flushes. To wash sediments with distilled water or any solution, to wash away sediments from filters and vessel walls, so-called washers are used (Fig. 30). They are also used for storing small quantities of distilled water. A flask with a capacity of 0.5 to 2 liters can be used for washing. To do this, select a rubber stopper for the flask, in which two holes are drilled. A tube bent at an acute angle is inserted into one of them;

Rice. 30. Flushes. Rice. 31. Flushing with a Kjeldahl attachment.

in this case, one end of the tube should reach almost to the bottom of the flask, and the other end should be pulled back. A tube bent at an obtuse angle is inserted into the other hole. The end of this tube, located inside the flask, should protrude from the stopper no more than 3-5 cm.

Distilled water or some solution is poured into the flask up to the neck and tightly closed with a stopper. When working, the end of a short tube bent at an obtuse angle is taken into the mouth and, blowing air into the flask, a stream of water is obtained from another tube, which is directed, for example, onto the wall of a funnel to wash away the sediment into the lower part of the filter, etc.

If you have to use the washer frequently, to make the work easier, it is recommended to put a rubber bulb on the air supply tube; it can be used to regulate both the strength of the jet (when washing away sediment from the walls of the dish) and the amount of liquid poured.

Sometimes washers are made with a ground-in stopper equipped with two tubes.

The liquid in the washer may become contaminated with dust, etc., through the open end of the tube. To prevent the possibility of such contamination, you can insert a Kjeldahl adjustment into the plug and blow air into the washer through it (Fig. 31). The use of such a nozzle is especially desirable in cases where you have to work with hot solutions or hot water, or with solutions of unpleasant-smelling substances (H2S, NH3, etc.).

The liquid consumption for washing sediments should be minimal; it is regulated by changing the diameter of the hole in the tube through which the water is poured.

The washer drain tube must be completely filled with water so that there are no air bubbles in it. If they are present, the liquid may splash when poured out of the washer. To remove bubbles, gently blow air into the washer so that the bubbles come out slowly.

The disadvantage of ordinary washers is that when working with volatile or toxic substances or gas solutions, as well as with hot water, the possibility of vapors or gases entering the mouth cannot be ruled out.. In Fig. 32 shows improved washers that do not have this drawback. One of them (Fig. 32, a) has a Bunsen valve attached to the lower end of a tube bent at an obtuse angle, which prevents vapors or gases from entering the mouth. Another washer (Fig. 32, b) is also equipped with a safety tube. To do this, a third hole is drilled in the plug covering the flusher, into which a short glass tube bent at an obtuse angle is inserted. When working with such a washer, close the opening of the safety tube with the thumb of your right hand, place your index finger on (or under) the tube through which a stream of liquid flows out of the washer, and blow air through the tube with the valve. When a slight excess pressure is created in the wash, the wash is taken away from the mouth and, holding it with your hand, direct the stream of flowing liquid where it is necessary. In order to stop the leakage of liquid from the flusher, remove your finger from the hole in the safety tube, as a result of which the pressure inside the flusher is equalized with the external pressure.

Such improved washers are very convenient to use for serial washing of sediments, when filling volumetric flasks, etc.

When heating the water in the wash, the flask should be opened as shown in Fig. 33. If the flask is closed, then when the water boils, the steam may throw out the stopper or the boiling liquid will begin to squeeze out

Rice. 32. Improved washers

Rice. 33. Heating the water in the washbasin

through the drain pipe and can burn the worker. Sometimes such pressure develops inside a tightly closed flask that it can burst.

To use a hot water wash without fear of burning your hands, the neck of the flask is covered with a heat-insulating layer. Such a layer can be a winding made of thick twine, a thin layer of porous plastic, or thick paper tape, the ends of which are secured with insulating tape or thread. You can also use sheet asbestos. A piece of thin sheet asbestos is first moistened with water, and then tightly wrapped around the neck of the flask. After drying, good thermal insulation is obtained. Wet asbestos can be wrapped in gauze.

If the flask does not have a heat-insulating layer, the hot neck should be held with a towel folded 2-4 times.

Conical flasks (Erlenmeyer) are widely used in analytical work (titration). They come in different capacities, with and without spouts, narrow-necked and wide-necked (Fig. 34). Conical flasks equipped with a ground-in stopper are called “flasks for determining iodine value.” They are also used in titrations using the iodometry method.

Flasks should only be heated through an asbestos mesh or in a bathhouse.

Figure 34. Conical flasks.

It is often necessary to close the neck of a conical flask. To do this, you can use watch glasses of the appropriate size, but it is much more convenient to use a glass lid (Fig. 35). The flask, closed with such a lid, can be rotated to mix its contents and tilted strongly.

Glass lids (caps) shown in Fig. 1 are also recommended. 36. Such caps are convenient for flasks in which distilled water or other reagents are stored, as they protect them well from dust and foreign substances.

Suction flasks (Bunsen) used in cases where filtration is carried out using a vacuum pump. The flask (Fig. 37) has a tube located in its upper part; the tube is connected with a rubber tube to a safety bottle, and then to a vacuum pump. A funnel secured in a rubber stopper is inserted into the neck of the flask. Suction flasks come in different capacities and shapes. Most often, conical flasks are used in laboratories as they are the most stable and convenient.

When filtering large quantities of liquid, a lot of filtrate collects in the flask, to drain which you have to disassemble the installation. In such cases, it is more convenient to use Bunsen flasks with a tap located near the bottom (Fig. 38). When using such flasks, the filtrate is drained through the tap into the prepared receiver, having previously closed the vacuum pump.

Bunsen flasks are made of thick glass, otherwise they may be crushed by atmospheric pressure during operation. It is recommended to cover working Bunsen flasks (to avoid accidents) with a towel or a box made of thick cardboard or tin.

Sometimes a sticky transparent polyvinyl chloride film is glued spirally onto the outer wall of the dish, layer upon layer so that each turn covers about half of the previous layer. This provides good protection against flying glass fragments during an explosion.

For each filtering flask, you should select in advance several rubber stoppers (two or three) with holes of different diameters that would fit the most commonly used funnels.

Bunsen flasks that have not yet been used should be checked first. First, the flask is inspected from the outside. If scratches are found on it, the flask cannot be used for work with a vacuum, since it will certainly burst when a vacuum is created. Then the flask is closed with a rubber stopper, wrapped in a towel or placed in a safety box and only then connected to the vacuum pump.

Rice. 35. Glass lid for flasks.

It is useful to insert a glass tube into the stopper of the flask, one end of which is drawn into the capillary. Using a vacuum pump, you need to achieve such a vacuum at which the flask will usually be used, and keep it under vacuum for at least 15 minutes.

Rice. 37. Bunsen flask filtering under vacuum - tap

Rice. 38. Bunsen flask with drain cock

You should also check that there are no pieces of metal or solids on the table that could scratch the bottom of the flask.

To work with vacuum, only proven Bunsen flasks can be used.

Retorts (Fig. 39) come in two types: without a tube and with a tube. The latter - with or without a ground stopper."

Rice. 39. Retorts.

The capacity of the retorts is up to 2-3 liters. Retorts with a capacity of more than 2-3 liters are very rare; They are produced only upon special order. When working with retorts that have a tube with a ground-in stopper, you must remember that immediately after the heating stops, the stopper should be removed.

Crystallizers are thin-walled glass flat-bottomed vessels of various diameters and capacities (Fig. 40). They are used in the recrystallization of be-. substances, and sometimes evaporation is carried out in them. Crystallizers can only be heated in a water bath.

Refrigerators are devices used for cooling and condensing vapors.

Direct refrigerators (Liebig). Very common in laboratories are Liebig refrigerators (Fig. 41), consisting of a long glass tube (for-Stos), one end of which is expanded. This tube is passed through a glass or metal jacket, or coupling, and secured with pieces of rubber tubing fitted to the ends of the coupling. Sometimes there are Liebig refrigerators in which the refrigeration tube is soldered to the jacket.

At the ends of the coupling (perpendicular to its axis) there is one outlet; Rubber tubes are put on them, one of which, located near the narrow end of the stem, is connected to a water tap, and the other is diverted into the drain pipe. When the tubes are connected in this way, the water in the refrigerator moves towards the vapors of the cooled liquid.

When connecting the refrigerator, the following rule must be observed; Water should always enter the refrigerator from the lower lower end and exit from the upper raised end. The cooling jacket (coupling) must always be filled with water. Otherwise, during prolonged distillation, the refrigeration tube will become very hot and may burst at the border with the water level. *

The rubber tubes used to connect the stem with the refrigeration jacket must be tied with thin wire or twine so that the water in this me-. ste did not leak.

When assembling the refrigerator, first of all you need to select the connecting rubber tubes, put them on the refrigeration jacket and, lubricating the inner walls of them

Rice. 41. Direct refrigerators (Liebig): a - with rubber couplings; b - with a polished section; 1 - for-shtos; 2 - shirt; 3 - connecting rubber tubes (couplings); 4 - processes.

The Bunsen flask is a prominent representative of personalized laboratory glassware. This is a vacuum vessel with a tube. Bears the name of its creator - chemist R.V. Bunsen, who worked in the 19th century. Sometimes called a Buchner flask or Kitasaki flask. It is considered an indispensable tool for vacuum filtration, cleaning, and drying of sludge.

Filter vessel design

A flat-bottomed conical flask with a side outlet is made of thick glass 3-8 mm. Domestic tableware is produced in accordance with GOSTs, from heat-resistant glass (sodium glass with additives) or, in accordance with ISO, from borosilicate glass, if the products are from a foreign manufacturer.

The glass must be heat-resistant, with the same thickness on the walls and bottom, since it can be pressed inward under the influence of vacuum. The thick-walled design allows the structure to be heated for a long time, but there should not be a large difference or sharp contrast, otherwise it will burst, especially since there is exposure to vacuum.

The upper cone of the vessel can be smooth; in such modifications, rubber stoppers with a cutout for the funnel spout or a rough one are inserted to combine dishes with the same grind.

The design of the Bunsen flask allows it to be used in any complex laboratory chain. The flat bottom plus the conical shape make it possible to place it on a shaker or fix it on a tripod.

The weakest point in the design is the outlet. If used carelessly, the tube breaks off, then the product can be thrown away. Models with a removable outlet are very convenient - plastic bolts and glass or plastic tubes can be changed if necessary. High-quality threads and gaskets allow you to achieve the required tightness. But such a removable outlet can only be screwed into the upper part of the vessel. The option with a removable outlet is suitable if the filtrate is not important.

Types of Bunsen flasks

Depending on the purpose and types of filtration, there are different manufacturing options:

• Standard – conical, with side outlet, top.
• With a lower tube, it is used to drain waste when the pump is turned off.
• With a three-way valve - in this modification, filtrate discharge is possible even when the pump is turned on.
• If there is no outlet in the vessel, then you can make a conditional vacuum system using a filter funnel with a side outlet.

The taps can be permanent or removable (plastic or plastic connector plus glass tube). The neck can be simple, without grinding, or with grinding. A funnel or part of a glass structure is inserted into it. The Buchner funnel is inserted into the upper cone using a rubber stopper with a suitable hole if the cone is not ground. If the cone is ground, then the funnel is inserted using an adapter. For greater tightness, the place where the funnels are inserted is additionally fixed with clamps of various types.

Types of Bunsen flasks by material and their features:

1. Glass - heat-resistant, the filling of the vessel is visible. Sufficiently stable, strong and durable. Inert with almost all substances.
2. Plastic - cheap, lightweight, moderately durable. May react with waste components. Unstable - the hose can turn them over, they need to be fixed.
3. Metal - strong, durable, expensive, very stable. React with some waste components. It’s inconvenient that you can’t see how much filtrate there is.

There are any types of volume – from 100 to 5000 cm³. Dishes of any size can be made to order. Dishes with a volume of 3.5 and 10 dm³ are available in cylindrical shape. You can assemble a filtration structure using a funnel with an outlet and a thick-walled, heat-resistant conical flask.

What is a Bunsen flask used for?

This type of laboratory glassware was invented for vacuum filtration, but the purpose of this process can be different:

• Cleaning, washing the sludge - washing it with various liquids.
• Obtaining a filtrate - filtering the reagents.
• Safety container for processes with vacuum.
• Obtaining gases.

Filters and filtration

The quality of filtration depends on the type of filter funnel - usually they take a Buchner funnel and put filters of the required density inside. Porcelain and glass funnels with a porous plate are also used. For a high-quality connection of the funnel and flask, use a rubber stopper with a hole, various clamps or dishes with polished sections.

Use paper, fabric, non-woven filters or special ones for ultrafiltration. You can put in several layers of material. In order for the paper to adhere better, there is no loss of sediment or filter, it is placed in a porcelain or glass funnel, poured with distilled water, try to squeeze out air bubbles and press tightly along the edges to the walls of the funnel (therefore, the diameter of the filter should be several millimeters larger than diameter of the watering can).

Buy a Bunsen flask

Being an indispensable laboratory instrument, this personalized flask is very common and is available at almost all points of sale of glassware. Having purchased a high-quality vacuum flask, you can use it for decades, since high requirements have made it possible to produce very durable products.

You can purchase domestically produced Bunsen flasks from the company, with certificates of quality and compliance with GOST, or imported borosilicate glass flasks that comply with ISO.