ANTITECK - A Life Sciences Company Provide Lab Equipment, Lab Consumable and Science Equipment

Single / Two / Three / Four Neck Flask

Single / Two / Three / Four Neck Flask used in laboratory

Teflon flask (single neck flask / two-neck round bottom flask / three-neck flask / four-neck flask)

The Teflon flask usually has a round belly and thin neck, which is distinctly different from the beaker. Its narrow mouth is used to prevent spills or to reduce evaporation of the solution and can be used with a rubber stopper to connect other Teflon equipment. Teflon flasks are generally used as containers when the solution needs to be reacted or refluxed for a long time. Usually, Teflon flask includes single neck flask, two-neck round bottom flask, three-neck flask, four-neck flask, etc.

If stirring is needed, the flask can be stirred smoothly by slightly turning the wrist with the mouth of the flask. For heating reflux, a magnetic stirrer can be placed inside the flask and stirred with a heating stirrer. Flasks can be divided into two types: flat bottom flasks and round bottom flasks, depending on their appearance.

The production of three-mouth flasks and multi-mouth flasks is made by blowing the flask body on a large furnace with a mold of a short-necked, thick-mouth flask, and then welding each mouth on the shoulder of the flask body on the lampwork. The multi-mouth flask is a short-necked, thick-mouthed, round-bottomed flask with three (three-necked) or four (four-necked) mouths welded around the shoulder of the flask body. The angle of the neck of the flask is divided into two types: straight-necked and slant-necked. Multi-mouth, mainly to match the complex experimental operation, can be assembled at the same time with more supporting instruments. Straight mouth, because all kinds of accessories are vertical devices, the center of the bottle gap, easy to stir the solution, not easy to damage other accessories instruments and design, but its disadvantage is that due to the small ball area, the distance between the neck of each bottle is close, not easy to install other instruments accessories, especially the specifications below 500mL more difficult. Slanting mouth, due to the existence of an oblique angle (10 ° oblique angle or 2 expansions oblique angle), when adding material can be added directly and evenly to the center of the bottom of the bottle. Bottle surface assembly of various instrument accessories also into a beveled angle, due to the bottle's shoulder gap, mouth and neck spacing, easy to install, especially small size flasks more obvious; but the center of the bottom of the bottle gap position less, stirring difficulties occur, easy to damage other accessories instruments.

Application of single neck flask / two-neck round bottom flask / three-neck flask / four-neck flask

a. Reactors between liquids and solids or liquids.

b. Assembly of gas reaction generators (room temperature, heating).

c. Distillation or fractional distillation of liquids (with a flask with a branch tube, which is also known as a distillation flask).

Product advantage of single-neck flask / two-neck round bottom flask / three-neck flask / four-neck flask

a. Each neck is a standard port, and each standard port is equipped with a stopper.

b. Removable for cleaning, smooth inner wall.

c. Operating temperature: -200℃~+250℃.

d. Teflon round bottom flasks can be processed according to customer requirements.

e. The lid is threaded to the body and between each neck and the lid for easy disassembly and cleaning.

Safe use method of single-neck flask / two-neck round bottom flask / three-neck flask / four-neck flask

a. It should be heated on an asbestos net so that it is heated evenly; when heated, the outer wall of the flask should be free of water droplets.

b. Flat-bottomed flasks cannot be used for heating for a long time.

c. When not heated, if a flat bottom flask is used as the reaction vessel, there is no need to fix it with an iron stand.

Precautions for use of single-neck flask / two-neck round bottom flask / three-neck flask / four-neck flask

a. Heat with an asbestos net. Other heat baths can also be used for heating. The amount of liquid does not exceed 2/3 of the volume, not less than 1/3 of the volume.

b. When configuring accessories (such as thermometers, etc.), use suitable rubber stoppers and pay special attention to checking whether the gas tightness is good.

c. Add a small amount of zeolite at the bottom of the flask in advance when distilling to prevent boil-off.

d. Heating should be placed on the asbestos net to make it evenly heated.

e. The distillation must be completed by closing the piston before stopping the heating to prevent back-siphoning.

Single neck flask

Single-neck flask is a common heating and screening vessel used in chemical laboratories. It is widely used for heating and generally needs to be padded with asbestos mesh to be used with clamping instruments such as an iron stand.

Feature of single neck flask

a. Smooth surface, no protrusion, beautiful and generous.

b. The choice of excellent glass material is subject to high temperature, high hardness, and high light transmission rate.

c. Various specifications. Flasks can be customized according to customer requirements.
Volume / mlStandard grind specification

Two-neck round bottom flask

The glass of the two-neck round bottom flask is lead-free environmental glass. This glass is a clear solid at room temperature. It forms a continuous network structure when molten. During cooling the viscosity gradually increases and hardens into a non-crystalline silicate non-metallic material.

Feature of two neck round bottom flask

a. High borosilicate glass

b. High strength, thickened, and high temperature resistant

c. Standard grinding mouth, complete specifications

d. Stable material, high light transmission rate

e. Good sealing performance

Three-neck flask

A three-necked round-bottom flask is a common chemical glass instrument, also known as a three-neck flask. When the solution reacts for a long time, condensation reflux and reduces loss.

The 3-neck round bottom flask is widely used in organic chemistry experiments and usually has the appearance of a round belly with a thin neck. It has three mouths and can be used to add multiple reactants at the same time or to add a condenser. Its narrow mouth is used to prevent spills or to reduce evaporation of solutions and can be used with a rubber stopper to connect other glass equipment. The opening of the flask does not have the same protruding notch as the beaker, so it is easier to pour the solution down the outer wall, so a glass rod is usually used to touch the mouth of the flask to prevent the solution from flowing down the outer wall. If you need to stir, you can hold the mouth of the flask and turn your wrist slightly to stir it smoothly or use a special mixer.

Three-necked flasks are used in laboratories for synthesis reactions of organic substances, or more complex boiling, fractionation, and purification operations. It is often assembled with thermometers, condenser tubes, stirring bars, partition funnels, and other instruments to form fractionation devices, distillation devices, or reflux devices. 250-3000mL is used for constant analysis and 5000-10000mL is used for industrial small batch production.

Use of three-neck flask

A. Heating by an open fire

Open flame heating includes direct heating with an alcohol lamp or pad with asbestos net direct heating. There are two types of heating: direct heating and indirect heating. This heating method is suitable for experiments that require rapid heating and for experiments that require less precise temperatures.

B. Thermal domain heating

Thermal domain heating includes waters, oil baths as well as sand baths. Indirect heating can be used when direct heating causes uneven heating together or when the temperature is difficult to control.

C. Heating apparatus

The more common heating apparatus is the electric stove, oven, etc. The use of heater heating is suitable for experiments requiring higher temperatures or longer experiments.

Four-neck flask

The four-neck flask has extremely low dissolution and precipitation capabilities. It is a vessel for storing masking standards, highly corrosive, expensive ultra-high purity reagents.

Feature of four neck flask

a. High-temperature resistance: -200~+250℃ use temperature.

b. Low-temperature resistance: the temperature can be maintained at 5% in -196℃ low temperature.

c. Corrosion resistance: resistant to strong acid, strong alkali, aqua regia, and various organic solvents.

d. Insulation resistance: dielectric properties are independent of temperature and frequency.

e. High lubrication: the lowest coefficient of friction among solid materials.

f. Non-adhesive: Does not adhere to any substance.

g. Non-toxic: physiologically inert and can be implanted in the human body.

How to buy single neck flask / two-neck round bottom flask / three-neck flask / four-neck flask?

ANTITECK provide lab equipment, lab consumable, manufacturing equipment in life sciences sector.
If you are interested in our single neck flask / two-neck round bottom flask / three-neck flask / four-neck flask or have any questions, please write an e-mail to, we will reply to you as soon as possible.

    AntiTeck Life Sciences Limited

    A1-519, XingGang GuoJi, Yingbin Road, Huadu, Guangzhou, China, 510810
    Free Quote
    linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram
    We use cookies in order to give you the best possible experience on our website. By continuing to use this site, you agree to our use of cookies.
    Privacy Policy