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The Mr. Coffee French Press
Technical Description
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1 General Description
The Mr. Coffee French Press is a manual kitchen device that produces coffee from ground coffee beans and hot water. It is often
found in a kitchen or dining area and is an alternative to electric or automatic coffee makers. The Mr. Coffee French Press costs
around $12, and if used properly should work for many years. The low cost of a French press makes it a viable method of brewing coffee at home for people who may not be able to afford a larger device. A French press is also sometimes known simply as
a coffee press or a cafetière.
The device is small and light enough to lift with one hand, and consists of two main parts: a glass carafe that holds the beverage, and a plunger assembly that is pressed into the carafe in order to separate the coffee grounds from the water. The carafe
has a plastic handle that allows a user’s hand to fit through comfortably. The plunger assembly consists of a plunger shaft with
a handle at one end and the filter mesh and plates at the other, as well as the pouring cap, which the plunger shaft passes
through. The pouring cap is not fixed to the shaft and may move up and down the plunger shaft freely. The wider parts of the
plunger assembly (the filter mesh, filter plates, filter coil, and pouring cap) are constructed to be slightly smaller than the width
of the carafe, so that when at rest the assembly can sit comfortably inside the carafe. When not in use, the pouring cap sits on
the top lip of the carafe, near the spout, and the filter mesh and filter plates are suspended just above the bottom of the carafe
at the end of the plunger shaft (see Figure 1).
Figure 1: The coffee press at rest.
Figure 2: The coffee press with plunger raised.
The handle is connected to the carafe by way of a single flat-head screw that passes through a metal band wrapped around the
cylinder of the carafe. This metal band is fixed to the carafe with glue. The plunger shaft has an round handle at its top end that
is affixed with glue. At the other end, the metal rod of the plunger shaft terminates in a screw that fastens into a rivet that connects the two filter plates. The filter mesh sits between the two filter plates on the plunger shaft, and since it is contained between the two plates it is unable to move up and down the plunger shaft. The filter coil sits between the filter mesh and upper
filter plate, and ensures that the mesh does not contact the upper plate. The filter coil is not attached to any part of the assembly, but since it has a smaller radius than the other filter components, it is contained between the two filter plates.
The entire coffee press, when at rest, measures 21 cm tall, 10 cm in diameter, and is 16 cm wide (diameter of carafe plus protrusion of spout and handle).
Technical Description: Mr. Coffee French Press
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2 Components
The Mr. Coffee French Press consists of two main parts (see Figures 3 and 4): the carafe (1) and the plunger assembly (2). The
plunger assembly rests inside the carafe when the press is not in use (see Figure 1).
Figure 3: The carafe.
Figure 4: The plunger assembly.
2.1 Carafe
The carafe assembly consists of a glass cylinder (1) with an attached handle (2). The cylinder rests on its closed end. The end
that points upward is open and allows water to be poured in and the plunger assembly to sit inside when in use. The open end
of the carafe features a small spout approximately 1 cm deep that allows the pouring liquid to be directed. Directly opposite the
spout, attached to the outside vertical face of the carafe, a semicircular plastic handle approximately 10 cm in diameter is fixed
to the side of the carafe. The handle is fixed to the carafe via a screw that is attached to a metal band (3) that encircles the glass
cylinder.
10 cm
2.1.1 Cylinder
The glass cylinder is 10 cm in diameter
and 18 cm tall (see Figure 5). It is made
of tempered glass that is made to withstand liquids at temperatures up to the
boiling point. One end of the cylinder is
open, allowing liquids to be poured in
and out. The open end features a 1 cm
spout that allows liquid to be directed
when pouring. One side of the cylinder
opposite the open end is closed, and
the closed end sits on the ground when
the device is at rest.
18 cm
Metal band
10 cm
Glass cylinder
Handle
Figure 5: Carafe components and dimensions.
Technical Description: Mr. Coffee French Press
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2.1.2 Handle
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5 cm
The handle is made of matte black plastic and is semicircular in shape. It is 10 cm tall
and has a radius of 5 cm, so it extends from the cylinder 5 cm (see Figure 6). The
handle’s opening is wide enough for most users’ hands, and its outer surface features a
slight concavity that allows the user’s thumb to rest comfortably on the handle while it
is being held or lifted. The handle contacts the cylinder at both of its ends, though only
the top end is fixed to the cylinder. The handle is connected to the metal band that
encircles the glass cylinder via a single screw.
10 cm
Figure 6: Handle dimensions.
2.1.3 Metal Band
The metal band encircles the glass cylinder and is 10 cm in diameter and 2 cm tall (see
Figure 7). The metal band is attached to the glass cylinder with glue. The band is not a
complete circle. It is a near-complete circle that terminates in two flat prongs. These
prongs extend perpendicular from the cylinder by 1 cm and each feature a hole which
allows the screw that connects the handle to pass through. The metal band is printed
with the Mr. Coffee logo on one side, halfway between the handle and the cylinder’s
spout.
10 cm
1 cm
2 cm
Figure 7: Metal band dimensions.
2.2 Plunger Assembly
The plunger assembly comprises a
number of parts that work in tandem. A
round plastic handle (1) connects to the
metal plunger shaft (2), which passes
through the pouring cap (3) and terminates in a rivet (4) which connects the
plunger shaft to the upper filter plate
(5), filter coil (6), filter mesh (7) and lower filter plate (8).
When at rest, the plunger assembly sits
inside the carafe. The pouring lid holds
the assembly in place while resting on
the lip of the glass cylinder. The filter
plates and mesh are fixed at the end of
the plunger shaft and sit just above the
bottom of the cylinder (see Figure 1).
10 cm
Handle
20 cm
Pouring cap
Plunger shaft
Filter plates
Filter coil
Filter mesh
Figure 8: Plunger assembly components and dimensions.
Technical Description: Mr. Coffee French Press
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The pouring cap is not fixed to the plunger shaft, so when it is held in place by the lip of the glass
cylinder, moving the plunger shaft up and down moves the filter plates up and down inside the cylinder. This action is used to ‘press’ the coffee grounds and separate them from the finished coffee,
so that when the user pours the beverage, they get only coffee and not grounds in their mug.
2.2.1 Plunger Handle
The plunger handle is a matte black plastic disk with a diameter of 4.5 cm and a depth
of 2 cm (see Figure 9). Underneath the disk the handle narrows into a small hollow post
with a diameter of 1 cm. This post is an anchor for the plunger shaft, which is fixed inside the anchor post with glue.
4.5 cm
2 cm
The plunger handle can be grasped comfortably with the fingers to pull up on the
plunger shaft, and it can be pressed with the palm or the fingertips when the device is
used to brew coffee.
1 cm
2.2.2 Plunger Shaft
Figure 9: Plunger handle dimensions.
The plunger shaft is a straight, cylindrical metal rod with a diameter of 0.5 cm and a length of 16 cm.
The plunger shaft is fixed to the plunger handle with glue, and on the opposite end screws into a
metal rivet which secures the filter plates and filter mesh. The plunger shaft passes through the
middle of the pouring cap, which is not fixed on the plunger shaft and can move freely up and down
the shaft.
When the device is in use, the pouring cap rests in the glass cylinder and the rest of the plunger
assembly is moved up and down vertically.
2.2.3 Pouring Cap
The pouring cap is a cylindrical matte black plastic cover with a wide upper lip and a
slightly narrower band underneath. The wider upper portion of the cap has a diameter
of 10 cm, while the lower band has a diameter of 8.5 cm and is 2.7 cm high (see Figure
10).
The lower band features a series of slits which allow liquid to pass through when pouring. If these slits are rotated away from the glass cylinder’s spout, liquid will be less
likely to escape the device if it is tilted. When the user is ready to pour coffee, the pouring cap can be rotated to align the slits with the spout.
10 cm
2.7 cm
8.5 cm
Figure 10: Pouring cap dimensions.
2.2.4 Rivet
The rivet is a small metal post with a diameter of 0.7 cm and a height of 1.2 cm. The rivet is hollowed, which allows the plunger shaft to fasten into it via a screw. The rivet features a slightly narrower section in its middle, around which are fastened the upper filter plate, the filter mesh, and
the lower filter plate.
2.2.5 Upper Filter Plate
The upper filter plate is a bowl-shaped metal disk perforated by numerous small holes. It has a diameter of 9 cm (see Figure 11). The lower, sunken section of the disc has a diameter of 7 cm. The
upper rim of the disc features evenly-spaced holes which are 2 mm in diameter and spaced 4 mm
apart.
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On the lower, sunken part of the disc, a ring of holes 4 mm in diameter and 6 mm apart encircles an
additional ring of holes the same size as those on the upper rim: 2 mm in diameter and 4 mm apart.
In total, the holes comprise three ring shapes, one ring of large holes buffered by two rings of smaller holes.
These perforations allow liquid to flow past the filter plate and still ensure that the filter plate keeps
the filter mesh in place. When the device is used, the upper filter plate helps to push the coffee
grounds to the bottom of the carafe.
2.2.6 Filter Coil
The filter coil is a coiled ring of metal wire that sits between the upper filter plate and
the filter mesh. The filter coil encircles an area approximately 8.5 cm in diameter. The
coil is not fixed to any part of the device, but is held in place because it is of a smaller
diameter than both the upper filter plate and the filter mesh.
9 cm
The filter coil ensures that the upper filter mesh and filter plate do not come into contact. This eases the flow of liquid through the filter assembly by ensuring that all parts
of the filter mesh are open on both sides.
2.2.7 Filter Mesh
The filter mesh is a disc made of a fine metal wire with a diameter of 9 cm. The wire is arranged in a
very fine mesh, which allows liquid to pass through it but not solids. The filter mesh is fixed between the upper and lower filter plates, and is separated from the upper filter plate by the filter coil.
Figure 11: The filter assembly. From
top to bottom, this includes the upper
filter plate, the filter coil, the filter
mesh, and the lower filter plate.
When the device is used, the filter mesh is the main component that separates the coffee grounds
from the brewed coffee. The filter plates push the much less sturdy filter mesh through the liquid in
the process.
2.2.8 Lower Filter Plate
The lower filter plate is a metal disc with a diameter of 9 cm (see Figure 12). The lower
filter plate features four holes spaced evenly around the perimeter of the disc. The
holes are rounded and roughly triangular in shape, and are 3.5 cm wide at their widest
point, which is closest to the outside rim of the filter plate.
9 cm
The lower filter plate holds the filter mesh in place along with the upper filter plate. The
larger holes on the lower filter plate allow liquid to quickly pass it by and reach the filter mesh, where the coffee grounds become separated from the rest of the liquid.
Figure 12: The lower filter plate.
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3 Cycle of Operation
Brewing coffee with the Mr. Coffee French Press is easy. You will need coffee that is ground slightly larger than for electric coffee brewers, since the wire filter mesh cannot strain coffee as finely as paper coffee filters can.
1.
The plunger assembly is removed from the carafe.
2.
The desired amount of ground coffee is placed into the bottom of the carafe.
3.
The coffee press is filled with a desired amount of very hot (but not boiling) water.
CAUTION: Boiling water should not be used. Boiling water may cause the carafe to break.
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1
3
4.
The plunger assembly is placed into the carafe with the plunger handle pulled upward.
5.
After 5 minutes has elapsed, the plunger handle is gently pressed down until the filter assembly has reached the bottom
of the carafe.
6.
The coffee is poured from the carafe through the slits in the pouring cap.
5 minutes
4
7.
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After use, the carafe is cleaned by removing the coffee grounds and rinsing with soapy water.
Technical Description: Mr. Coffee French Press