MPE GPX.DC User manual

Model GPX.DC Dual Chamber
Disc Style Coffee Grinder
H:\DATA\WORD\MANUALS\Coffee\GPX-DC Manual Revised 05-25-07.doc
Model GPX.DC
Dual Chamber Disc Style Coffee Grinder
Modern Process Equipment, Inc.
3125 S. Kolin Av., Chicago, Illinois 60623
Ph. [phone] Fx. [phone]

Model GPX.DC Dual Chamber
Disc Style Coffee Grinder
H:\DATA\WORD\MANUALS\Coffee\GPX-DC Manual Revised 05-25-07.doc
OVERVIEW
The Model GPX.DC Dual Chamber Disc Style Coffee Grinder has two
grinding heads, driven by a common motor, to produce different flavors, blends, or
roasts of coffee without the need to clean out the grinder between runs. Each head
utilizes a pair of precision cut "diamond hard" grinding plates to produce up to 400
lbs per hour of a full range of coffee grinds. The grinder utilizes a 5 HP (1200 RPM)
motor to drive dual rotors, each with an auger feeder and a rotating grinding disc.
The rotor also incorporates turbo vanes to maximize throughput and minimize
product accumulation within the grinding head.
The gap between the rotating grinding disc and the stationary grinding disc
(mounted directly opposite the rotating disc, on the grinder housing) determines the
type of coffee grind produced. Turning the grind adjustment knob sets the gap
between the grinding discs and provides the capability of "dialing in" any one of a
full range of coffee grinds, from drip to espresso.
On "American" style coffees, it may be necessary to utilize the dechaffer on
the GPX grinder. By utilizing the weight on the dechaffing arm, back pressure is
exerted on the coffee being expelled from the grinder, thereby breaking up the
"chaff" (broken coffee skin) which is released when the bean is ground. By moving
the weight outward on the dechaffing arm, the back pressure and the resulting level
of dechaffing is increased. When producing very fine coffees (melitta, espresso,
turkish), the dechaffing level should be minimized or, in some cases, eliminated by
removing the weight.
Each grinding head is operated separately; it is not possible to grind using
both heads at the same time. Automatic feed gates are included on each grinding
head, the gates open and close automatically to supply coffee to the grinding head
that is in use.
PRIOR TO OPERATION FOR THE FIRST TIME
Motor rotation should be checked prior to operation for the first time.
1. Open head #1 gate using the switch on the control panel.
2. Press the “Head 1 Grinder Start” button.
3. The head should rotate clockwise as viewed from the head #1
discharge end. The rotor can be seen by looking down through the
open slide gate.

Model GPX.DC Dual Chamber
Disc Style Coffee Grinder
H:\DATA\WORD\MANUALS\Coffee\GPX-DC Manual Revised 05-25-07.doc
OPERATION AND MAINTENANCE
Because of its uncomplicated design, the GPX.DC grinder is relatively simple to
operate. In preparation for grinding coffee, simply fill the hopper with the desired
amount of beans, set the dechaffer arm weight*, "dial in" the desired grind on the
grind adjustment knob, and place the feed gate control switch in automatic.
CAUTION!
TO AVOID GRINDER DAMAGE, THE GRINDER MUST BE ALLOWED TO
COME TO A COMPLETE STOP (~10 SECONDS) PRIOR TO STARTING THE
OPPOSITE HEAD
To start grinding, simply press the Start button for the grinding head. The motor will
start and the feed gate will open automatically.
To stop grinding but leave the grinding head running, turn the gate control knob to
close. This is useful when filling small bags, for example. It is preferred to open
and close the feed gate rather than start and stop the motor.
When the grinding run is complete, lift the dechaffer arm to remove any excess
coffee, and press the Stop button. The feed gate will shut automatically.
To switch grinding heads, simply stop the grinder and restart the other head.
* As a starting point, the dechaffer arm weight should be set at 1/2 the arm distance
for medium to coarse grinds, and at the bottom of the arm (fully toward the
machine) for finer grinds.
Gate Control Switch
The feed gate control switch has three positions.
Open – The feed gate will open when the grinding head is in use.
Close – The feed gate stays closed.
Auto – The feed gate automatically opens when the grinding head starts and
automatically shuts when the head stops.

Model GPX.DC Dual Chamber
Disc Style Coffee Grinder
H:\DATA\WORD\MANUALS\Coffee\GPX-DC Manual Revised 05-25-07.doc
NOTE
TO REMOVE ANY COFFEE BUILDUP ABOVE DECHAFFING GATE, SWING
THE DECHAFFING ARM UPWARD UNTIL IT IMPACTS ON THE “KNOCKER”,
AS SHOWN IN THE DRAWING BELOW.
DO NOT PUSH OR FORCE HANDLE DOWN
To change the grind range on the grind adjustment knob, loosen the knob
set screws, rotate the adjusting screw in the middle of the knob (Clockwise=Finer)
to the desired point, and retighten the knob set screws.
CAUTION!
LOCK OUT OR DISCONNECT MOTOR PRIOR TO ATTEMPTING WORK,
REPAIR OR REMOVAL OF COVER FROM THIS UNIT.
On occasion, the grinder will require disassembly for cleaning and/or
grinding disc replacement. To disassemble, remove the front cover after first
removing the (3) front cover screw knobs. After the front cover has been removed,
the rotor can be pulled out either by hand or by utilizing "ejector screws" on the
rotor insert (part #11 on drawing SG-4395C) which, when screwed in, act against
the motor shaft to force the rotor out. Refer to drawing SG-4395C for further details
on the internal construction of the grinder.
DECHAFFING
ARM
KNOCKER
DECHAFFING
GATE
CLEANING POSITIONNORMAL OPERATING POSITION
DECHAFFING
GATE
KNOCKER
DECHAFFING
ARM

Rev. Sept 2021
Model GPX Precision Disc Style Coffee Grinder
Don't push down on the dechaffing
arm as this may damage the
dechaffing gate.
Do lift up the dechaffing arm and
lower the coffee bag at the end of
grinding. This empties the burr
housing.

Rev. Sept 2021
Model GPX Precision Disc Style Coffee Grinder
Video on how to use and
not use a dechaffing gate.
How to install a dechaffing gate
and add a dechaffing arm.
MPE webpage for troubleshooting
common GPX issues.

Model GPX.DC Dual Chamber
Disc Style Coffee Grinder
H:\DATA\WORD\MANUALS\Coffee\GPX-DC Manual Revised 05-25-07.doc
Drawings
GPX Dual Head Style Store Grinder on Bench Stand SG-4226B
Wiring Diagram for Model GPX.DC Grinder EL -4230B
GPX Dual Head Style Store Grinder on Stand with
8/50 lb. Hoppers SG-4308C
Model GPX.DC Disc Style Grinder Part List SG-4395C

Model GPX.DC Dual Chamber
Disc Style Coffee Grinder
H:\DATA\WORD\MANUALS\Coffee\GPX-DC Manual Revised 05-25-07.doc

Model GPX.DC Dual Chamber
Disc Style Coffee Grinder
H:\DATA\WORD\MANUALS\Coffee\GPX-DC Manual Revised 05-25-07.doc

Model GPX.DC Dual Chamber
Disc Style Coffee Grinder
H:\DATA\WORD\MANUALS\Coffee\GPX-DC Manual Revised 05-25-07.doc

Model GPX.DC Dual Chamber
Disc Style Coffee Grinder
H:\DATA\WORD\MANUALS\Coffee\GPX-DC Manual Revised 05-25-07.doc

Model GPX.DC Dual Chamber
Disc Style Coffee Grinder
H:\DATA\WORD\MANUALS\Coffee\GPX-DC Manual Revised 05-25-07.doc