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Fritted Funnel

Fritted funnel used in laboratory

1. What is fritted funnel?
    1.1 What is fritted?
    1.2 How to make fritted funnel?
2. Use of fritted funnel?
    2.1 Precautions when cleaning fritted funnel
    2.2 How to clean fritted funnel?
    2.3 Note after using the fritted flask
3. How to buy fritted funnel?

What is fritted funnel?

Fritted funnel is used for vacuum (suction) filtration. It has a porous (sintered) glass disk in the center that allows the filtrate to drain while leaving the solids behind. It is easier to use than Brinell funnels because there is no filter paper to worry about, but they are more difficult to clean.

What is fritted?

a. At high temperatures, the inter-bonding of solid particles of raw ceramics. The grains grow and the voids (pores) and grain boundaries tend to decrease. Through the transfer of material, its total volume shrinks, density increases, and finally becomes a dense polycrystalline sintered body with a certain microstructure, a phenomenon called sintering.

b. Sintering (fritted) is a process for the production of inorganic solid materials. In the preparation of inorganic solid compounds using solid-phase reactions, the rate of the reaction is controlled by the diffusion process and often requires a high temperature to allow the reaction to proceed efficiently. Some other solid compounds are compounds composed of solid-liquid phases. In melting, decomposition reactions occur, so sintering should generally be carried out below the melting point of the product to ensure that a homogeneous phase is obtained. However, the sintering temperature should not be too low, otherwise, the rate of solid-phase reaction will be too low. In many cases, sintering needs to be carried out in a specific atmosphere or vacuum. It is important to control the partial pressure of the gas phase in the sintering process. Especially when the system under study contains ions with variable valence, the gas-phase partial pressure of the solid-phase reaction will directly affect the composition and structure of the product. For example, in the synthesis of copper-based oxide high-temperature superconductors, the sintering process must be carried out at a tightly controlled oxygen partial pressure to ensure that superconducting materials with defined structure, composition, and copper valence distribution are obtained.

c. It is an important step in the processing of polytetrafluoroethylene (PTFE). PTFE preforms must be sintered to become useful products. Sintering is the process of heating the preforms above the melting point (327°C) and holding them at this temperature for a certain period so that the polymer molecules gradually change from a crystalline form to an amorphous form and the dispersed resin particles are bonded into a continuous whole by mutual fusion diffusion. The sintered preforms are cooled from a clear gel to a solid, milky opaque product.

How to make fritted funnel?

1) Sintering. Heat treatment of powder or billet at a temperature lower than the melting point of the main components, to improve its strength through metallurgical bonding between the particles.

2) Packing material. A material into which the pressed billet is buried for separation and protection during the pre-firing or sintering process.

3) Pre-sintering. The heating of a pressed billet at a temperature lower than the final sintering temperature.

4) Pressure. A sintering process in which a single axial pressure is applied while sintering.

5) Loose-powder sintering/gravity sintering. The powder is sintered directly without pressing.

6) Liquid-phase sintering liquid-phase sintering. At least two components of the powder or pressed billet in the formation of a liquid phase sintering.

7) Over-sintering. The sintering temperature is too high and (or) sintering time is too long resulting in the deterioration of the final performance of the product sintering.

8) Under-sintering. The sintering temperature is too low and (or) sintering time is too short resulting in the product does not achieve the required performance of sintering.

9) Infiltration. The process of filling the pores in the unsintered or sintered products with metals or alloys that have a lower melting point than the melting point of the product in the molten state.

10) Dewaxing, burn-off. Heat discharge of organic additives (binder or lubricant) in the press billet.

11) Mesh belt furnace. Generally, the muffle-protected mesh belt realizes the parts in the furnace continuously convey the sintering furnace.

12) Walking-beam furnace. The sintering furnace in which the parts placed in the sintering plate is transferred in the furnace by the walking-beam system.

13) Pusher furnace. Sintering furnace in which the parts are loaded into a sintering boat and the parts are transferred inside the furnace by a pusher system.

14) Neck formation. When sintering, the formation of a neck-like linkage between the particles.

15) Blistering. The phenomenon of forming blistering on the surface of sintered parts due to violent gas discharge.

16) Sweating. The phenomenon of liquid phase oozing out during the heating treatment of the pressed billet.

17) Sinter skin. A surface layer formed on the sintered part during sintering, whose properties are different from those inside the product.

18) Relative density. The ratio of the density of the porous body and the density of the same component material in the non-porous state is expressed as a percentage.

19) Radial crushing strength. The rupture strength of the sintered cylinder specimen was measured by applying radial pressure.

20) Porosity. The porosity of all pores in the volume of the porous body and the total volume of the ratio.

21) Diffusion porosity. The pores are formed by the diffusion of material from one group element to another due to the Kirkendall effect.

22) Pore size distribution. The material exists in all levels of pore size by the number or volume of the percentage.

23) Apparent hardness. The hardness of the sintered material measured under the specified conditions includes the influence of pores.

24) Solid hardness. The hardness of a phase or particle or a region of the sintered material is measured under the specified conditions, which excludes the influence of pores.

25) Bubble-point pressure. The minimum pressure is required to force the gas through the liquid-impregnated product to produce the first bubble.

26) Fluid permeability. Measured under the specified conditions in the unit of time the number of liquid or gas through the porous body.

Use of fritted funnel?


Precautions when cleaning fritted funnel

a. Wear a closed lab coat.

b. Wear safety glasses with a face shield.

c. Wear suitable gloves.

d. Do this in a fume hood with windows closed.

e. Ensure that all excess organic material is washed out of the sinter before cleaning.

How to clean fritted funnel?

Method A

There are some common laboratory substances that will allow you to clean fritted funnel, such as nitric acid, concentrated nitric acid, sulfuric acid, and hydrogen peroxide. Nitric acid is a simple solution for cleaning fritted funnels and usually solves the problem. However, sometimes more drastic conditions need to be used. Sulfuric acid and hydrogen peroxide work every time.

a. Attach/connect the fritted funnel to the vacuum Büchner flask.

b. Add a small amount of concentrated sulfuric acid to cover the surface of the sinter.

c. Add a little hydrogen peroxide and let it sit.

d. When the ingredients have been cooked for a minute or so, briefly and gently vacuum them. This should be enough to vacuum out the sinter.

e. Allow the cocktail to settle and cool and clean all equipment with plenty of water. Be careful not to pour the contents on yourself.

Method B

a. In a fume hood, attach the Büchner funnel with fritted disc to be cleaned and make sure it is secure. Connect the vacuum to the flask.
Note: If acetone or other organic solvents remain, wash with plenty of water.

b. Add 50 ml of sulfuric acid, or enough to cover the entire surface of the Büchner funnel sintering body.

c. Carefully add 15 ml of 30% hydrogen peroxide or 1/3 volume of sulfuric acid to the fritted Büchner funnel and back off!

d. Let the reaction proceed for about one minute and then apply a fast vacuum (just enough to pull the solution through the sinter into the flask and the sinter is dry.)

e. Monitor the reaction. Do not leave it unattended. Once the reaction has subsided, allowing the reaction mixture to cool in the flask overnight.

f. Thoroughly wash the flask, sinter, funnel, and all used equipment in the water. The fritted funnel should now be clean with optimal flow conditions.

Note after using the fritted flask

a. If the fritted flask is still hot after use, do not leave it unattended.

b. Allow the fritted flask to cool completely overnight, as this allows all oxygen to dissipate.

c. Do not store fritted flasks in airtight containers.

d. Do not dispose of fritted Buchner flasks in spent solvent bottles.

e. Check your laboratory's disposal regulations, as some require fritted flasks to be collected as hazardous waste, while others allow neutralization and disposal of fritted flasks with large amounts of water.

How to buy fritted funnel?

ANTITECK provide lab equipment, lab consumable, manufacturing equipment in life sciences sector.
If you are interested in our fritted funnel or have any questions, please write an e-mail to [email protected], we will reply to you as soon as possible.

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