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Agitated Nutsche Filter Dryers Vs Buchner Funnels

September 23, 2022
Posted by: test
category:
- Filtration
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The agitated Nutsche filter dryer and the Büchner funnel are designed to carry out the same
fundamental task – solid-liquid separation. There are however, significant differences between the
two in terms of functionality and applications.
In this blog post, we’re taking a close look at the benefits offered by the agitated Nutsche filter dryer
compared to the much simpler Büchner funnel.

How Does a Buchner Funnel Work?

The Büchner funnel is a common piece of chemical lab equipment designed for filtration. The
mechanism is relatively straightforward: the funnel contains either a perforated plate (over which a
paper filter is placed) or a fritted glass plate which can be used without a paper filter. The narrow
part of the funnel is typically sealed to a side-arm flask (also known as a Buchner flask), with the arm
of the flask connected via a tube to a vacuum pump. The liquid to be filtered is poured into the top
of the funnel and is drawn through the paper filter/fritted glass by a combination of gravity and
suction provided by the vacuum pump. Suspended solids are filtered out, and the filtrate collects in
the bottom of the side-arm flask.
Typically made out of porcelain, glass, or plastic, Büchner funnels are inexpensive pieces of
equipment that provide much faster filtration than simply allowing gravity to draw liquid through a
filter. Büchner funnels support a relatively wide range of applications. For example, funnels of an
inch or so in diameter are a common sight on chemistry lab benchtops. In contrast, large models of
up to around a meter in diameter can support pilot plant scale applications (often with the aid of
“trowels” to manually smooth over fissures in the compacted solid material). Troweling the cake in
this manner introduces the problem of operator variability and human error.
However, for industrial applications – especially pharmaceuticals or fine chemicals – Büchner funnels
are typically avoided in favour of agitated Nutsche filter dryers.

How Agitated Nutsche Filter Dryers Work

An agitated Nutsche filter dryer is a specialist piece of equipment designed to provide a more
sophisticated filtration method than Büchner funnels.
Agitated Nutsche filter dryers use a bladed drive assembly to provide low-speed, high-torque
agitation/mixing of the slurry, ensuring the height of the “cake” (i.e. filtered solids) doesn’t impact
the filtration rate. One key difference between an agitated Nutsche filter dryer and a Büchner funnel
is that while Büchner funnels only provide suction from below, agitated Nutsche filter dryers provide
both suction from below and pressure from above. The result is faster filtration and much lower
moisture content in the filtered solid.
As filtration advances, the blades inside the agitated Nutsche filter dryer rise to the top of the cake
to automatically smooth out cracks and/or preferential channels. Therefore, operator variability is
not a problem as with the smoothing process in the Büchner funnel.
Once solids have been fully separated, an agitated Nutsche filter dryer will wash out any remaining
filtrate and impurities. Büchner funnels do support washing, but agitated Nutsche filter dryers
provide superior washing either via traditional methods (in which a solvent seeps through the
product cake) or by re-slurry washing (similar to conventional washing but using the agitator to

plough the solvent into the cake before pressing – this reduces the amount of solvent required and
optimises the removal of impurities).

The similarities between the two different types of filters diverge here, with agitated Nutsche filter
dryers gaining added benefits. Products discharged from a Büchner funnel need drying in a
secondary piece of equipment, such as a tray dryer or desiccator. Both methods of drying are small-
scale, which naturally makes them unsuitable for many industrial applications.
By comparison, filtered and washed solids are dried within an agitated Nutsche filter dryer. This can
be carried out by either pressurised gas heating or vacuum-assisted heating. The agitator plays a
vital role by providing drying homogeneity and breaking down difficult products.
Finally, the product is discharged from the agitated Nutsche filter dryer. The agitator once again
plays a vital role by gradually pushing the cake to the discharge valve.

It is also worth noting that agitated Nutsche filters provide a fully closed environment which enables
certain processes that can be difficult – if not impossible – using a Buchner filter. Many toxic, highly
potent products, and a range of volatile solvents must be handled with care using a Büchner filter,
possibly requiring external ventilation. This is not the case with an agitated Nutsche filter.

Choosing a Laboratory Rotary Evaporator

September 23, 2022
Posted by: test
category:
- Laboratory Supplies
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Understanding the basics of Rotary Evaporators before buying them

Rotary evaporation is the process of reducing the volume of a solvent by distributing it as a thin film
across the interior of a vessel at elevated temperature and reduced pressure which promotes the
quick removal of excess solvent from less volatile samples. Rotary Evaporators are used in chemical
laboratories. This instrument uses evaporation to gently and efficiently remove the solvents from
samples including many organic, inorganic, and polymeric materials.

How a Rotary Evaporator works?

The main components of a rotary evaporator include a motor unit, a vapor duct, a vacuum system, a
heated fluid bath, a condenser with either a coil passing coolant, a condensate-collecting flask and a
mechanical or motorized mechanism. In a rotary evaporator, the motor rotates the evaporation flask
or vial containing the user’s sample. Vapor duct is the axis for sample rotation, and is a vacuum-tight
conduit for the vapor being drawn off the sample. The vacuum system substantially reduces the
pressure within the evaporator system. The vacuum system can be as simple as a water aspirator
with a trap immersed in a cold bath (for non-toxic solvents), or as complex as a regulated mechanical
vacuum pump with refrigerated trap. A heated fluid bath, which is usually water, heats the sample.
The condenser used in rotary evaporator can be simple or complex, depending upon the goals of the
evaporation, and any propensities the dissolved compounds might give to the mixture. The
condensate-collecting flask is located at the bottom of the condenser and it catches the distilling
solvent after it re-condenses. The mechanical or motorized mechanism quickly lifts the evaporation
flask from the heating bath.

Considerations before buying a Rotary Evaporator

Rotation speed range (rpm), vacuum (mm Hg), temperature, pressure (mbar) and condenser are key
parts that should be considered when buying a Rotary Evaporator. You can decide on the type of
Rotary Evaporator suitable for your application based on the size, type and sensitivity of the
samples. For example, if the samples are acids, they require an acid-resistant system.

Safety precautions

Safety is an important component of every laboratory operation and procedure. Although
evaporation is a simple operation, there are hazards associated with it including implosions resulting
from use of glassware that contains flaws, such as star-cracks, explosions that may occur from
concentrating unstable impurities during evaporation or explosion due to taking certain unstable
compounds, such as organic asides and acetylides, nitro-containing compounds, molecules with
strain energy, etc. to dryness.
It is recommended to take precautions to avoid contact with rotating parts, particularly
entanglement of loose clothing, hair, or necklaces. In such cases, a rotating mechanism can draw the
user into the apparatus. In an incident like this, a user is subject to burns, sharps and chemical
exposure. Extra caution must also be applied to operations with air reactive materials, especially
when under vacuum. A leak can draw air into the apparatus and a violent reaction can take place.

Why is Borosilicate Glass Preferred for Laboratory Glassware?

September 13, 2022
Posted by: test
category:
- Laboratory Supplies
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If you’ve ever browsed lab glassware options, you’ve likely come across a material called borosilicate glass. If you’re unfamiliar with borosilicate glass, it can be difficult to tell the difference between it and standard lab glassware. Dive into the question of why borosilicate glass is preferred for lab glassware and learn more about this material below.

What Is Borosilicate Glass?

Borosilicate glass is a special type of glass that contains silica and boron trioxide as its glass-forming constituents. It is made up of about 15 percent boron trioxide. One of the most well-known qualities of borosilicate glass is its low coefficient of thermal expansion. Thermal expansion is a material’s tendency to change shape, density, and more due to changes in temperature. However, with its low coefficient of thermal expansion, borosilicate glass is resistant to this thermal shock and cracking under extreme temperature changes.

Benefits of Borosilicate Glass

Borosilicate glass is unique to other types of glass due to its low coefficient of thermal expansion. Thanks to this, it is more durable than other types of glass. In some instances, you could even transport borosilicate glass directly from a cold storage freezer to a heater or oven rack without worrying about the glass cracking. This is one advantage that borosilicate glass possesses over other glassware. This also allows it to hold freezing or boiling hot materials with ease, which comes in handy in many situations. Many fields and occupations take advantage of these unique qualities and benefits of borosilicate glass.

Applications of Borosilicate Glass

There are many industries that use borosilicate glass due to its unique conditions. It makes an excellent choice for laboratory glassware when standard glassware cannot handle extreme temperatures. On the opposite spectrum, many chefs and cooking institutions use borosilicate glassware in cooking utensils. As bakeware and cookware, borosilicate glass handles extreme oven temperatures or freezing temperatures to cool foods. Many aircraft designers and manufacturers use borosilicate glassware in their designs due to its durability. And these are just the beginning of borosilicate glass applications. We hope this explanation helps answer the question, “Why is borosilicate glass preferred for laboratory glassware?” If you’re interested in utilizing borosilicate glassware in your own laboratory space, check out our selection of scientific glassware here at Global Antico Process Systems.