Laboratory
funnels made with plastic have displaced glass as a preferred for funneling
applications. Though the glass funnels are still popular for better chemical
resistance and inertness still plastic funnels are chosen as they are
durable and economical. No surprise that in most of the secondary school
laboratories plastic funnels are commonly used.
A funnel is essentially a conically shaped pipe, for channelling or
funnelling either liquids or fine-grained solids. The plastic funnel fits
into containers with a small mouth or opening. There are two main
constituents of a plastic funnel or for that matter any funnel. They are a
bowl and a spout. A funnel's bowl is the portion at the top shaped like a
large bowl. The bowl has a wide diameter which narrows itself as it goes
down to take the shape of a cone. There is a hole at the base form where the
spout of the funnel is reached.
Plastic funnels are used for transferring solids or liquids into flasks,
cylinders, beakers or other containers with narrow neck openings. Plastic
funnels are very useful for filling sample bottles with powders or granular
material.
Plastic funnels come in a variety of shapes and sizes depending on the
quantum of material that is being poured. It is designed to fit all sizes of
bottles or containers. The small plastic funnels are ideally suited for
filling up small vials, batteries,bottles, hip flasks etc. The funnel's
small tip fits nicely into the top of the vials. The plastic funnels are an
important constituent in the process of filtration being used with filter
papers.
Resins for Manufacturing Plastic Funnels
Some of the material with which plastic funnels are manufactured are the
following
- Polyethylene both HDPE and LDPE
- Polystyrene
- Polypropylene
- PFA (Perfluoroalkoxy copolymer)
- PTFA
Features of Plastic
Funnels
Depending upon the application some of the features to look for in plastic
funnels de include:
- Ribbed interiors. Exterior ribbing eliminates air lock.
- Angles slope that facilitates filtration
- Non wetting surfaces that ensures complete drainage and does away
with the fluid loss during funneling
- Some funnels have an air vent molded in for eliminating glugging of
liquids during transfer
- Smooth walls prevents clogging of powders
- Some funnels can also be autoclaved
Popular Plastic
Funnels
Polypropylene
Funnel
Economical polypropylene funnels are appropriate for continuous laboratory
work as they are unbreakable and durable. Polypropylene funnels comes with
features like ridges for preventing vapor lock. They can also be autoclaved
at around 120º C. Polypropylene funnels are ideal for use with organic
solvents and comparatively stronger acids & alkalis.
Polypropylene Analytical Funnel
Polypropylene analytical funnels as the name suggests are designed
specifically for analytical chemistry applications. The polypropylene
analytical funnel comes with a variety of designs. One particular design for
a quick filtration process, has the body of the funnel at a precise 600
angle. They are provided with internal and external ribs. Polypropylene
analytical funnels are compatible with standard size filter papers. They can
also be autoclaved.
Micro
Funnels
Micro funnels are meant for micro applications such as filling burettes,
manometers or other small containers or bottles. Generally made of
polypropylene they are also steam autoclavable at around 121º C
Plastic
Separatory Funnel
Plastic separatory funnel provides excellent strength and contact clarity
and strength. They also come in a variety of sizes and designs. Separatory
funnels made with polypropylene are very popular. They show excellent
resistance against all the chemicals and can also be autoclaved. They are
supplied with leakproof screw closure.
Seperatory
Funnel Holder
Separatory funnel holder is a standard accessory with a separatory funnel
It is molded with non-corrosive polypropylene. The funnel holder has a front
opening for giving a clear view of the solution and permits an unhindered
positioning of separating funnels. Two tepered wedges provided firm grip on
the rods.
LDPE
Funnels
LDPE funnels are very popular for transferring liquids and feature both
internal as well as external ribbing. The external ribbing aids air release.
LDPE funnels are able to withstand high temperatures.
HDPE Funnels
Rigidly constructed heavy duty HDPE funnels suits vacuum filtration very
well. The HDPE funnels can also with stand high temperatures.
Plastic
Buchner Funnels
Plastic buchner funnels are generally composed of two pieces and are used
for filtration process. For making plastic buchner funnels ar
chemical-resistant polyethylene is a good choice.
Powder Funnel
Fast and efficient powder funnels are ideal for student use for
transferring powders or large volume of liquids.
Disposable
Funnels
Disposable funnels are economical single use funnels. Transparent
polystyrene or translucent polypropylene is generally used for making them.
Some of the features to look for in disposable funnels include
- Lightweight
- Reinforced rims
- Inside fluting
- Angled tapering
Disposable Long Stem Funnels
For making disposable long stem funnels are made with polypropylene. Poly
propylene provides a number of crucial advantages like chemical resistance,
nonstickability, nonstaining surface etc. Cone and stem are made extra rigid
with more ribs for withstanding the rigours of autoclaving.
Disposable Short Stem Funnels
Disposable short stem funnels are made using clear and tough molded
polypropylene. These funnels can withstand alkalis, acids and organic
solvents. Some of the features include
- Nonwetting surface that drains completely
- Ribbed inside surface
- 60° slopes for easy filtration
- External ribbing to prevent air lock.
- Can be autoclaved at around 121°C
Funnel
Holder
For making funnel holder non-corrosive high density polyethylene is an
excellent choice. Funnel holder along with a clamp consist of two bushings
and support rods.
PTFE
Funnels
As PTFE is a material with excellent physical and chemical properties, no
doubt PTFE funnels can be used under adverse conditions. Some of the
exceptional features of PTFE funnels are as under:
- PTFE funnels can be used easily with ultra-pure material because
there would be no leach out that causes contamination as might be the
case with glass funnels
- PTFE funnles are non stick. There is absolutely nothing that can
stick to the smooth walls of these funnles
- PTFE funnels display nearly total chemical resistance
PFA Funnels
Inert and non-contaminating PFA funnels finds extensive use in speciality
lab like electronics and semiconductor, environmental as well as biotech
labs. Unique features of PFA funnels include:
- Non- stick surfaces
- Compatible with ultra pure liquids
- Excellent chemical resistance
Polystyrene Funnels
Polystyrene funnels are suitable for funneling applications involving
aqueous solutions and weak to mild acidic or alkali solutions. These funnels
can also be used for single use applications. Typical features include non-
wetting surfaces, ribbed interiors, tapered angles.
