Nordson Rhino GMT 360 Reference guide

GMT 360 RhinoBulk
Unloader Controls
Customer Product Manual
Part 303 864A
NORDSON CORPORATION AMHERST, OHIO USA

2000 Nordson Corporation
All rights reserved
303 864A
Issued 11/00
Manual 23-25
Nordson Corporation welcomes requests for information, comments and inquiries about its products. General
information about Nordson can be found on the Internet using the following address: http://www.nordson.com.
Address all correspondence to:
Nordson Corporation
Attn: Customer Service
555 Jackson Street
Amherst, OH 44001
Notice
This is a Nordson Corporation publication which is protected by copyright. Original copyright date 2000.
No part of this document may be photocopied, reproduced, or translated to another language without the prior written
consent of Nordson Corporation. The information contained in this publication is subject to change without notice.
AccuJet, AquaGuard, Asymtek, Automove, Autotech, Blue Box, CF, CanWorks, Century, Clean Coat, CleanSleeve,
CleanSpray, Compumelt, Control Coat, Cross-Cut, Cyclo-Kinetic, Dispensejet, DispenseMate, Durafiber, Durasystem,
Easy Coat, Easymove Plus, Econo-Coat, EPREG, ETI, Excel 2000, Flex-O-Coat, FlexiCoat, Flexi-Spray, Flow Sentry,
Fluidmove, Fluidshooter, FoamMelt, FoamMix, Helix, Horizon, Hose Mole, Hot Shot, Hot Stitch, Isocoil, Isocore, Iso-Flo, JR,
KB30, Little Squirt, Magnastatic, MEG, Meltex, MicroSet, Millenium, Mini Squirt, Moist-Cure, Mountaingate, MultiScan,
Nordson, OmniScan, Opticoat, Package of Values, PluraFoam, Porous Coat, PowderGrid, Powderware, Pro-Flo, ProLink,
Pro-Meter, Pro-Stream, PRX, RBX, Ready Cost, Rhino, S. design stylized, Saturn, SC5, SCF, Select Charge, Select Coat,
Select Cure, Shur-Lok, Slautterback, Smart-Coat, Spray Squirt, Spraymelt, Super Squirt, Sure-Bond, Sure Coat, System
Sentry, Tela-Therm, Trends, Tribomatic, UniScan, UpTime, Veritec, Versa-Coat, Versa-Screen, Versa-Spray, Watermark, and
When you expect more. are registered trademarks – – of Nordson Corporation.
ATS, Auto-Flo, AutoScan, BetterBook, Chameleon, CanNeck, Check Mate, CPX, Control Weave, Controlled Fiberization,
EasyClean, Ebraid, Eclipse, Equi=Bead, Fillmaster, Gluie, Ink-Dot, Kinetix, Maxima, MicroFin, Minimeter, Multifil, OptiMix,
Pattern View, PluraMix, Primarc, Prism, Process Sentry, PurTech, Pulse Spray, Seal Sentry, Select Series, Sensomatic,
Shaftshield, Spectral, Spectrum, Sure Brand, Swirl Coat, Vista, Walcom, and 2 Rings (Design)
are trademarks – – of Nordson Corporation.
Trademarks
Parker is a registered trademark of Parker Hannifin Corporation.

Table of Contents
i
2000 Nordson Corporation
All rights reserved 303 864A
Issued 11/00 Manual 23-25
Table of Contents
1. Introduction 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Qualified Personnel 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. Intended Use 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4. Regulations and Approvals 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5. Personal Safety 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
High-Pressure Fluids 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6. Fire Safety 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Halogenated Hydrocarbon Solvent Hazards 1-5. . . . . . . . . . . . . . . .
7. Action in the Event of a Malfunction 1-5. . . . . . . . . . . . . . . . . . . . . . . . . .
8. Disposal 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. GMT 360 Dual Bulk Unloaders 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Theory of Operation 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hydraulic and Electrical Components 2-3. . . . . . . . . . . . . . . . . . . . . .
Pneumatic Controls 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. Specifications 2-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Supply 2-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Supply 2-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overall Dimensions 2-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Baseplate Mounting Holes 2-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. General 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Automatic Changeover Installation 3-2. . . . . . . . . . . . . . . . . . . . . . . . . .
Pneumatic Connections 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Connections 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. New Equipment Installation 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4. Adjusting the Empty Drum Settings 3-5. . . . . . . . . . . . . . . . . . . . . . . . . .
5. Adjusting the Runaway Sensor 3-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. Safety
2. Description
3. Installation

Table of Contents
ii
2000 Nordson Corporation
All rights reserved
303 864A
Issued 11/00
Manual 23-25
1. Introduction 4-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. New Equipment Startup 4-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. Routine Operating Procedures 4-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Elevator Movement 4-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Daily Startup 4-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Container Change 4-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removing the Empty Container 4-6. . . . . . . . . . . . . . . . . . . . . . . .
Installing a Full Container of Material 4-7. . . . . . . . . . . . . . . . . . . .
Bleeding the Pump 4-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shutdown 4-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Restart after Shutdown 4-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4. Changing to a Different Material 4-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5. Controller Operation 4-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Keypad 4-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Controller Menu Options 4-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PURGE Screen 4-12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHANGE Screen 4-13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SETUP Menu 4-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MANUAL Screen 4-16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. Introduction 5-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Daily Maintenance 5-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Changing the Filter Element 5-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. Weekly Maintenance 5-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. Introduction 6-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Procedures 6-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. Repair Guidelines 7-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Service and Repair Guidelines 7-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. Preparing to Remove the Hydraulic Section 7-4. . . . . . . . . . . . . . . . . . .
4. Bleeding Air Pressure from the Air Cylinders 7-4. . . . . . . . . . . . . . . . . .
5. Reinstating Air Pressure to the Cylinders 7-6. . . . . . . . . . . . . . . . . . . . .
6. Adjusting the Runaway Sensor 7-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Support Assembly 8-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4. Operation
5. Maintenance
6. Troubleshooting
7. Repair

Table of Contents
iii
2000 Nordson Corporation
All rights reserved 303 864A
Issued 11/00 Manual 23-25
1. Introduction 8-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Using the Illustrated Parts List 8-1. . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Parts Lists 8-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GMT 360 Dual Unloader Parts 8-2. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pneumatic Module Parts 8-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manual Shut-Off Parts 8-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Empty/Limit Bracket Parts 8-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Support Assembly Parts 8-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Elevator/Blow-off Control Module Parts 8-11. . . . . . . . . . . . . . . . . . .
GMT 360 Pump Controllers Parts 8-15. . . . . . . . . . . . . . . . . . . . . . . .
Drum Hold Down Kit 8-17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Check Valve 8-18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Depressurization Module Parts 8-18. . . . . . . . . . . . . . . . . . . . . . . . . .
Runaway Valve Parts 8-20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust Module Parts 8-20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filter Kits 8-22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accessory Kit 8-22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8. Parts

Table of Contents
iv
2000 Nordson Corporation
All rights reserved
303 864A
Issued 11/00
Manual 23-25

1998 Nordson Corporation
All rights reserved Issued 10/98 S1EN–03–[SF–LECAP]–7
Section 1
Safety

Safety
1-0
1998 Nordson Corporation
All rights reserved
Issued 10/98
S1EN–03–[SF–LECAP]–7

Safety
1-1
1998 Nordson Corporation
All rights reserved Issued 10/98 S1EN–03–[SF–LECAP]–7
Section 1
Safety
Read and follow these safety instructions. Task- and equipment-specific
warnings, cautions, and instructions are included in equipment
documentation where appropriate.
Make sure all equipment documentation, including these instructions, is
accessible to persons operating or servicing equipment.
Equipment owners are responsible for making sure that Nordson
equipment is installed, operated, and serviced by qualified personnel.
Qualified personnel are those employees or contractors who are trained
to safely perform their assigned tasks. They are familiar with all relevant
safety rules and regulations and are physically capable of performing
their assigned tasks.
Use of Nordson equipment in ways other than those described in the
documentation supplied with the equipment may result in injury to
persons or damage to property.
Some examples of unintended use of equipment include
using incompatible materials
making unauthorized modifications
removing or bypassing safety guards or interlocks
using incompatible or damaged parts
using unapproved auxiliary equipment
operating equipment in excess of maximum ratings
Make sure all equipment is rated and approved for the environment in
which it is used. Any approvals obtained for Nordson equipment will be
voided if instructions for installation, operation, and service are not
followed.
1. Introduction
2. Qualified Personnel
3. Intended Use
4. Regulations and
Approvals

Safety
1-2
1998 Nordson Corporation
All rights reserved
Issued 10/98
S1EN–03–[SF–LECAP]–7
To prevent injury follow these instructions.
Do not operate or service equipment unless you are qualified.
Do not operate equipment unless safety guards, doors, or covers are
intact and automatic interlocks are operating properly. Do not bypass
or disarm any safety devices.
Keep clear of moving equipment. Before adjusting or servicing
moving equipment, shut off the power supply and wait until the
equipment comes to a complete stop. Lock out power and secure the
equipment to prevent unexpected movement.
Relieve (bleed off) hydraulic and pneumatic pressure before adjusting
or servicing pressurized systems or components. Disconnect, lock
out, and tag switches before servicing electrical equipment.
While operating manual spray guns, make sure you are grounded.
Wear electrically conductive gloves or a grounding strap connected to
the gun handle or other true earth ground. Do not wear or carry
metallic objects such as jewelry or tools.
If you receive even a slight electrical shock, shut down all electrical or
electrostatic equipment immediately. Do not restart the equipment
until the problem has been identified and corrected.
Obtain and read Material Safety Data Sheets (MSDS) for all materials
used. Follow the manufacturer’s instructions for safe handling and
use of materials, and use recommended personal protection devices.
Make sure the spray area is adequately ventilated.
To prevent injury, be aware of less-obvious dangers in the workplace
that often cannot be completely eliminated, such as hot surfaces,
sharp edges, energized electrical circuits, and moving parts that
cannot be enclosed or otherwise guarded for practical reasons.
5. Personal Safety

Safety
1-3
1998 Nordson Corporation
All rights reserved Issued 10/98 S1EN–03–[SF–LECAP]–7
High-pressure fluids, unless they are safely contained, are extremely
hazardous. Always relieve fluid pressure before adjusting or servicing
high pressure equipment. A jet of high-pressure fluid can cut like a knife
and cause serious bodily injury, amputation, or death. Fluids penetrating
the skin can also cause toxic poisoning.
If you suffer a fluid injection injury, seek medical care immediately. If
possible, provide a copy of the MSDS for the injected fluid to the health
care provider.
The National Spray Equipment Manufacturers Association has created a
wallet card that you should carry when you are operating high-pressure
spray equipment. These cards are supplied with your equipment. The
following is the text of this card:
WARNING: Any injury caused by high pressure liquid can be
serious. If you are injured or even suspect an injury:
Go to an emergency room immediately.
Tell the doctor that you suspect an injection injury.
Show him this card.
Tell him what kind of material you were spraying.
MEDICAL ALERT–AIRLESS SPRAY WOUNDS: NOTE TO PHYSICIAN
Injection in the skin is a serious traumatic injury. It is important to treat
the injury surgically as soon as possible. Do not delay treatment to
research toxicity. Toxicity is a concern with some exotic coatings injected
directly into the bloodstream.
Consultation with a plastic surgeon or a reconstructive hand surgeon may
be advisable.
The seriousness of the wound depends on where the injury is on the
body, whether the substance hit something on its way in and deflected
causing more damage, and many other variables including skin
microflora residing in the paint or gun which are blasted into the wound.
If the injected paint contains acrylic latex and titanium dioxide that
damage the tissue’s resistance to infection, bacterial growth will flourish.
The treatment that doctors recommend for an injection injury to the hand
includes immediate decompression of the closed vascular compartments
of the hand to release the underlying tissue distended by the injected
paint, judicious wound depravement, and immediate antibiotic treatment.
High-Pressure Fluids

Safety
1-4
1998 Nordson Corporation
All rights reserved
Issued 10/98
S1EN–03–[SF–LECAP]–7
To avoid a fire or explosion, follow these instructions.
Ground all conductive equipment in the spray area. Use only
grounded air and fluid hoses. Check equipment and workpiece
grounding devices regularly. Resistance to ground must not exceed
one megohm.
Shut down all equipment immediately if you notice static sparking or
arcing. Do not restart the equipment until the cause has been
identified and corrected.
Do not smoke, weld, grind, or use open flames where flammable
materials are being used or stored.
Do not heat materials to temperatures above those recommended by
the manufacturer. Make sure heat monitoring and limiting devices are
working properly.
Provide adequate ventilation to prevent dangerous concentrations of
volatile particles or vapors. Refer to local codes or your material
MSDS for guidance.
Do not disconnect live electrical circuits while working with flammable
materials. Shut off power at a disconnect switch first to prevent
sparking.
Know where emergency stop buttons, shutoff valves, and fire
extinguishers are located. If a fire starts in a spray booth,
immediately shut off the spray system and exhaust fans.
Shut off electrostatic power and ground the charging system before
adjusting, cleaning, or repairing electrostatic equipment.
Clean, maintain, test, and repair equipment according to the
instructions in your equipment documentation.
Use only replacement parts that are designed for use with original
equipment. Contact your Nordson representative for parts
information and advice.
6. Fire Safety

Safety
1-5
1998 Nordson Corporation
All rights reserved Issued 10/98 S1EN–03–[SF–LECAP]–7
Do not use halogenated hydrocarbon solvents in a pressurized system
that contains aluminum components. Under pressure, these solvents
can react with aluminum and explode, causing injury, death, or property
damage. Halogenated hydrocarbon solvents contain one or more of the
following elements:
Element Symbol Prefix
Fluorine F “Fluoro-”
Chlorine Cl “Chloro-”
Bromine Br “Bromo-”
Iodine I “Iodo-”
Check your material MSDS or contact your material supplier for more
information. If you must use halogenated hydrocarbon solvents, contact
your Nordson representative for information about compatible Nordson
components.
If a system or any equipment in a system malfunctions, shut off the
system immediately and perform the following steps:
Disconnect and lock out system electrical power. Close hydraulic and
pneumatic shutoff valves and relieve pressures.
Identify the reason for the malfunction and correct it before restarting
the system.
Dispose of equipment and materials used in operation and servicing
according to local codes.
Halogenated Hydrocarbon
Solvent Hazards
7. Action in the Event of a
Malfunction
8. Disposal

Safety
1-6
1998 Nordson Corporation
All rights reserved
Issued 10/98
S1EN–03–[SF–LECAP]–7

2000 Nordson Corporation
All rights reserved 303 864A
Issued 11/00 Manual 23-25
Section 2
Description

Description
2-0
2000 Nordson Corporation
All rights reserved
303 864A
Issued 11/00
Manual 23-25

Description
2-1
2000 Nordson Corporation
All rights reserved 303 864A
Issued 11/00 Manual 23-25
Section 2
Description
See Figure 2-1.
Figure 2-1 shows both primary (A-Unit) and secondary (B-Unit) bulk
unloaders as they are built for GMT 360 applications. GMT 360
unloaders are available with two unloaders (an A-Unit and a B-Unit) and
a filter for use with adhesive materials (A); or two unloaders (an A-Unit
and a B-Unit) with a stand for use with mastic materials (B). Operation
switches between A- and B-Units automatically (via the controller
program) or manually (via operator intervention).
Rhino bulk unloaders are available in a variety of configurations, with
various hydraulic sections and controls. Rhino drum unloaders pump
Nordson-approved adhesives and sealant materials at room temperature
from 200-liter (55-gallon) containers.
GMT 360 unloaders are shipped with a rotary elevator control for elevator
operation, have a 65:1 air input to hydraulic output ratio pump with a
10-inch air motor, and have a drum (55-gallon) follower plate. A pail
(5-gallon) follower plate is available as a replacement.
Contact your Nordson representative if
you require more information about the other configurations available
for Rhino bulk unloaders
to verify that the material you wish to pump is compatible with your
equipment and setup
WARNING: This manual is written to reflect the controls and
components of the GMT 360 dual unloaders configuration only.
The procedures included are specific to the product
configuration. Use this manual to familiarize yourself with the
safe and proper operation of GMT 360 unloaders. Do not use
this manual when operating unloaders not built to GMT 360
specifications.
1. GMT 360 Dual Bulk
Unloaders

Description
2-2
2000 Nordson Corporation
All rights reserved
303 864A
Issued 11/00
Manual 23-25
2325001A
A. Dual unloaders with filter
B. Dual unloaders with mastic stand
Fig. 2-1 GMT 360 Rhino Bulk Unloaders, A- and B-Units
1. GMT 360 Dual Bulk
Unloaders
(contd)

Description
2-3
2000 Nordson Corporation
All rights reserved 303 864A
Issued 11/00 Manual 23-25
An unloader typically pumps a constant supply of material to dispensing
guns or process applicators. The hydraulic section of the unloader is a
dual-acting, positive-displacement, demand-type operation pump. The
pump can handle high viscosity materials, some of which may be
abrasive. It is often used in applications that require rapid delivery of
material to dispensing guns.
CAUTION: If the material is too abrasive or generally not
compatible, equipment may wear out prematurely and
components may be damaged.
See Figure 2-2.
The operator places a full (open, non-tapered, undamaged) container of
material under the unloader frame. When the unloader is pressurized
and DOWN movement is initiated, the elevator lowers the follower
plate (8) and hydraulic section (9) into the material. Once the pump
strokes, the downward movement of the follower plate forces material
into the hydraulic section. Material is pumped through the material output
hoses and to the applicator or gun. The follower plate seals (7) create a
sealed compartment below the follower plate and prevent material from
leaking past the follower plate. A bleed valve (10) enables the operator
to remove air from the pump body. A bleeder stem (6) enables the
operator to remove air from beneath the follower plate to ensure proper
contact with the material in the container. An output check valve (5)
prevents backward material flow into the pump.
The operator interfaces with unloader operation via the GMT 360 pump
controller (2) and keypad (3). Depressurization intervals and pump
runaway parameters can be programmed into the pump controller.
(Specific pump controller operation and programming information is
located in the
Operation section of this manual.) The runaway sensor (4)
will stop pump operation when too many pump strokes occur within a set
period of time.
2. Theory of Operation
Hydraulic and Electrical
Components

Description
2-4
2000 Nordson Corporation
All rights reserved
303 864A
Issued 11/00
Manual 23-25
See Figure 2-2.
When a material container is emptied during unloader operation,
the empty drum sensor (11) causes the light (1) on the pump
controller to go on, indicating that a material container change is
necessary;
the pump controller automatically switches operation to the inactive
unloader; and
the operator is able to change material containers at the inactive
unloader by raising the follower plate, replacing the empty container
with a full one, and lowering the follower plate into the new container.
The unloaders can be purged through the programmable logic controller
(PLC). The PLC is pre-wired to provide the following output signals:
dirty filter
drum A empty
drum B empty
runaway A
runaway B
The controls that initiate elevator movement and operate the unloaders
are pneumatic. Because of the latent (potential) power in a pressurized
unloader, an unloader under pressure from the air supply is considered
active even if it is not pumping. Only a non-pressurized pump is
considered inactive.
Hydraulic and Electrical
Components
(contd)
Pneumatic Controls