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Model 286.20 Confining Pressure Intensifier
l
Product Information
015-020-201 B
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Copyright information © 2007 MTS Systems Corporation. All rights reserved.
Trademark information MTS is a registered trademark of MTS Systems Corporation.
Contact information MTS Systems Corporation
14000 Technology Drive
Eden Prairie, Minnesota 55344-2290 USA
Toll Free Phone: 800-328-2255 (within the U.S. or Canada)
Phone: 952-937-4000 (outside the U.S. or Canada)
Fax: 952-937-4515
E-mail: info@mts.com
http://www.mts.com
Publication information
Manual Part Number Publication Date
015-020-201 A
015-020-201 B
June 1991
August 2007
Page 3
Contents
Preface 5
About This Manual 6
Conventions 7
Technical Support 8
Introduction 13
Overview Of Typical Confining Pressure Control System 14
Description of Major Components 16
Specifications and Dimensions 18
Operation 19
Control Panel 20
High Pressure Precaution 22
High Temperature Precaution 22
Confining System Operation Considerations 23
Operating Procedures 27
Filling the Reservoir From An External Source 28
Filling the Pressure Intensifier From an External Container 30
Filling the Pressure Intensifier From The Reservoir 32
Filling the Triaxial Cell 34
Heating The Triaxial Cell 36
Pressurizing and Depressurizing The Confining Fluid 37
Cooling The Triaxial Cell and Confining Fluid 41
Emptying the Triaxial Cell 42
Draining the Reservoir to an External Location 44
manual name Contents
3
Page 4
4
Contents
manual name
Page 5
Preface
Safety first! Before you attempt to use your MTS equipment in your test system, read and
Contents About This Manual 6
understand the Safety manual. Like an automobile, your test system is very
useful—but if misused, it is capable of deadly force. You should not be afraid of
your test system, but you should always maintain a healthy respect for it.
Improper installation, operation, or maintenance of MTS equipment in your test
system can result in hazardous conditions that can cause severe personal injury or
death, and damage to your equipment and specimen. Again, read and understand
the Safety manual before you continue. It is very important that you remain aware
of hazards that apply to your test system.
Conventions 7
Technical Support 8
286.20 Pressure Intensifier Preface
5
Page 6
About This Manual
About This Manual
Purpose This manual provides detailed information about the Model 286.20 Confining
Pressure Intensifier. The information includes an overview and operation.
Summary This manual includes the following sections.
Introduction This section provides an overview of typical confining pressure control system, a
description of major components, and specifications.
Operation This section contains procedures for operations involving the flow and
pressurization of confining fluid.
Preface
6
286.20 Pressure Intensifier
Page 7
Conventions
Conventions
The following paragraphs describe some of the conventions that are used in your
MTS manuals.
Hazard conventions Hazard notices are embedded in this manual and contain safety information that
is specific to the task to be performed. Hazard notices immediately precede the
step or procedure that may lead to an associated hazard. Read all hazard notices
carefully and follow the directions that are given. Three different levels of hazard
notices may appear in your manuals. Following are examples of all three levels.
Note For general safety information, see the Safety manual included with your
system.
Danger notices Danger notices indicate the presence of a hazard which will cause severe personal
injury, death, or substantial property damage if the danger is ignored.
Warning notices Warning notices indicate the presence of a hazard which can cause severe
personal injury, death, or substantial property damage if the warning is ignored.
Caution notices Caution notices indicate the presence of a hazard which will or can cause minor
personal injury, cause minor equipment damage, or endanger test integrity if the
caution is ignored.
Other conventions Other conventions used in your manuals are described below:
Notes Notes provide additional information about operating your system or highlight
easily overlooked items.
Special terms The first occurrence of special terms is shown in italics.
Illustrations Illustrations appear in this manual to clarify text. It is important for you to be
aware that these illustrations are examples only and do not necessarily represent
your actual system configuration, test application, or software.
Electronic manual
conventions
This manual is available as an electronic document in the Portable Document
File (PDF) format. It can be viewed on any computer that has Adobe Acrobat
Reader installed.
Hypertext links The electronic document has many hypertext links displayed in a blue font. All
blue words in the body text, along with all contents entries and index page
numbers are hypertext links. When you click a hypertext link, the application
jumps to the corresponding topic.
286.20 Pressure Intensifier Preface
7
Page 8
Technical Support
Technical Support
Start with your
manuals
Technical support
numbers
MTS web site
www.mts.com
E-mail: General information:info@mts.com
Telephone HELPLine 800-328-2255
The manuals supplied by MTS provide most of the information you will need to
use and maintain your equipment. If your equipment includes MTS software, you
should look for README files for additional product information.
If you cannot find answers to your technical questions from these sources, you
can use the internet, telephone, or fax to contact MTS for assistance. You can also
fill out the Problem Submittal Form that is available on the MTS web site and in
the back of many MTS manuals that are distributed in paper form.
MTS provides a full range of support services after your system is installed. If
you have any questions about a system or product, contact MTS in one of the
following ways.
The MTS web site gives you access to our technical support staff by means of a
Problem Submittal Form and a Technical Support link.
• Problem Submittal Form:
www.mts.com > Contact MTS > Problem Submittal Form
• Technical Support:
www.mts.com > Contact Us > Service & Technical Support
Weekdays 7:00 A.M. to 6:00 P.M.,
Central Time
Fax 952-937-4515
Please include an MTS contact name if possible.
Preface
8
286.20 Pressure Intensifier
Page 9
Technical Support
Before you
contact MTS
Know your site number
and system number
Know information from
prior technical
assistance
MTS can help you more efficiently if you have the following information
available when you contact us for support.
The site number contains your company number and identifies your equipment
type (material testing, simulation, and so forth). The number is usually written on
a label on your MTS equipment before the system leaves MTS. If you do not
have or do not know your MTS site number, contact your MTS sales engineer.
Example site number: 571167
When you have more than one MTS system, the system project number identifies
which system you are calling about. You can find your project number in the
papers sent to you when you ordered your system.
Example system project number: US1.30123
If you have contacted MTS about this problem before, we can recall your file.
You will need to tell us the:
• MTS notification number
• Name of the person who helped you
Identify the problem Describe the problem you are experiencing and know the answers to the
following questions.
Know relevant computer
information
• How long has the problem been occurring?
• Can you reproduce the problem?
• Were any hardware or software changes made to the system before the
problem started?
• What are the model and serial numbers of the suspect equipment?
If you are experiencing a computer problem, have the following information
available.
• Manufacturer’s name and model number
• Operating software type and service patch information. Examples:
– Windows XP Service Pack 1 (SP1)
– Windows 2000 Service Pack 3 (SP3)
• Amount of system memory. Example: 512 MB of RAM.
• Amount of free space on the hard drive in which the application resides.
Example: 11.2 GB free space, or 72% free space.
• Current status of hard-drive fragmentation. Example: 3% total
fragmentation.
286.20 Pressure Intensifier Preface
9
Page 10
Technical Support
Know relevant software
information
If you contact MTS
by phone
For MTS software application problems, have the following information
available.
• TestWorks 4 version; for example Version 4.09
• Names of other non-MTS applications that are running on your computer,
such as screen savers, keyboard enhancers, print spoolers, and so forth
Your call will be registered by a HELPLine agent if you are calling within the
United States or Canada. Before connecting you with a technical support
specialist, your agent will ask you for your site number, name, company,
company address, and the phone number where you can normally be reached.
Identify system type To assist your HELPLine agent with connecting you to the most qualified
technical support specialist available, identify your system as one of the
following types:
• • Electromechanical materials test system
• • Hydromechanical materials test system
• • Vehicles test system
• • Vehicles component test system
• • Aero test system
Be prepared to
troubleshoot
Prepare yourself for troubleshooting while on the phone.
• Call from a telephone close to the system so that you can try implementing
suggestions made over the phone.
• Have the original operating and application software media available.
• If you are not familiar with all aspects of the equipment operation, have an
experienced user nearby to assist you.
10
Preface
286.20 Pressure Intensifier
Page 11
Technical Support
Write down relevant
information
After you call MTS logs and tracks all calls to ensure that you receive assistance and that action
Problem Submittal
Form in MTS manuals
Prepare yourself in case we need to call you back.
• Remember to ask for the notification number.
• Record the name of the person who helped you.
• Write down any specific instructions to be followed, such as data recording
or performance monitoring.
is taken regarding your problem or request. If you have questions about the status
of your problem or have additional information to report, please contact MTS
again.
In addition to the Problem Submittal Form on the MTS web site, there is also a
paper version of this form (postage paid) in the back of many MTS manuals. Use
this form to forward problems you are experiencing with your MTS equipment,
whether it be software, hardware, manuals, or service. This form includes check
boxes that allow you to select when you expect us to respond to your input. We
guarantee a timely response—your feedback is important to us.
286.20 Pressure Intensifier Preface
11
Page 12
Technical Support
12
Preface
286.20 Pressure Intensifier
Page 13
Introduction
Triaxial
Cell
Open Close
Confining Fluid Input
Open Close
Confining Fluid Output
Open Close
Reservoir Fill
Fluid
Reservoir
Open Close
Intensifier Fill
Pressure
Intensifier
Low Pressure
Relief
Pressure
Transducer
Low pressure line
High pressure line
286.20
Confining
Pressure
Intensifier
r
Fluid Filter
Off
Fluid Transfer Pump Control
Air supply in
100 psi max.
Air Driven
Hydraulic
Pump
Fluid Direction
A
B
C
C
A
B
Empty
Reservoir
From fluid
supply or to
empty fluid
Fill system from
fluid supply
using pump
Fill system
from reservoir
using pump
Confining
Pressure
AB
A
B
Air Direction
Air supply into empty
traxial cell.
Bleed air into reservoir
when filling triaxial cell.
psi
bar
High Pressure
Relief
Air Pressure
Relief
815
Fluid
Resivoir
Control
Panel
This section describes the Model 286.20 Confining Pressure Intensifier (CPI), its
role in the typical rock mechanics test system and other system components
typically used with the Confining Pressure Intensifier. Specifications and
dimensions are also included.
The Model 286.20 Confining Pressure Intensifier is designed to provide a source
of fluid at pressures suitable for use in the confining pressure chamber of a
triaxial cell. The CPI is used to fill the triaxial cell with confining fluid,
pressurize the fluid, control the pressure, and empty the fluid from the triaxial
cell at the conclusion of a test.
Some model versions produce confining pressures up to 140 MPa (20,000 psi).
When connected to a fluid-filled triaxial cell, the maximum fluid volume that can
flow during pressurization of the external device and its specimen can be as high
as 1300 cubic centimeters (80 cubic inches). See “Specifications and
Dimensions” on page 18 for specifications for all models.
286.20 Pressure Intensifier Introduction
13
Page 14
Overview Of Typical Confining Pressure Control
Overview Of Typical Confining Pressure Control System
The major system components typically used with the Confining Pressure
Intensifier are shown in the following figure.
14
Introduction
As shown in the figure, a separate hydraulic power supply acts as the primary
power source for the Confining Pressure Intensifier. Hydraulic fluid pressures up
to 21 MPa (3,000 psi) are translated into confining fluid pressures up to 140 MPa
(20,000 psi) under servo control provided by separate electronic controller
equipment.
Compressed air, driving a small fluid pump, provides the power to cause
confining fluid to flow between various system components before and after
pressurizing operations, while filling and/or emptying the triaxial cell, the
pressure intensifier, the reservoir, etc. The pump can also cause fluid to flow
between an external fluid container and either the CPI or the triaxial cell.
286.20 Pressure Intensifier
Page 15
Overview Of Typical Confining Pressure Control
Pressure and displacement transducers in the CPI provide signals proportional to
their respective variables, enabling the external electronic controller equipment
to measure these variables and to control either the pressure produced by the CPI,
or the linear displacement of the pressure intensifiers piston relative to a fixed
reference.
While the displacement transducer output signal is proportional to the
displacement of the pressure intensifiers piston, relative to a reference point, the
electronic control equipment associated with this transducer is usually calibrated
in units of volumetric displacement, cubic inches or cubic centimeters, a function
of linear displacement multiplied by the area of the pressure intensifiers piston
rod.
286.20 Pressure Intensifier Introduction
15
Page 16
Description of Major Components
1
2
4
3
5
6A
8
7
9
6B
Description of Major Components
The following figure and table identify and describe the major components of the
Model 286.20.
TEM COMPONENT DESCRIPTION
I
1 Cabinet
2 Reservoir
3 Operator control panel
Enclosure mounted on casters. Includes leveling legs for
stability and a hinged rear access door.
Clear acrylic container. Includes filler port with strainer
which also acts as a vent for escaping gases.
Panel contains all the valves used during operation and a
pressure gage which reads confining pressure. The panel
includes a schematic of the unit to aid in operation.
16
Introduction
286.20 Pressure Intensifier
Page 17
Description of Major Components
4 Pressure transducer
5 Pressure relief valve
6 Pressure intensifier
7 Hydraulic service manifold
8 Servovalve
9 Linear transducer
Provides a signal which represents the level of confining
fluid pressure being applied to the triaxial cell. The
signal is used by the electronic controller equipment as
feedback when pressure is the controlled variable.
Relieves pressure in the system if pressure exceeds the
CPI’s pressure rating by a certain amount.
Actuator which uses servovalve controlled hydraulic
fluid to pressurize the confining fluid. The top end,
identified as “6A,” is the high pressure, confining fluid
part of the actuator. The lower part, “6B,” is the low
pressure, hydraulic end.
Provides an interface between the external hydraulic
power supply and the pressure intensifier. Provides
mounting for various hydraulic components such as
accumulators and the servovalve.
Controls flow and pressure of hydraulic fluid applied to
the input side of the pressure intensifier.
Provides a signal to the test controller.
286.20 Pressure Intensifier Introduction
17
Page 18
Specifications and Dimensions
Specifications and Dimensions
The following tables list the dimensions, weights, and specifications for the
Model 286.20 Confining Pressure Intensifier.
Dimensions and Weights
P
ARAMETER ALL MODELS
Height 1825 mm (72 in.)
Width 600 mm (23.6 in.)
Depth 845 mm (33.3 in.)
Weight 454 kg (1000 lb.)
Reservoir Capacity 11.4 liters (3.0 gallon)
PARAMETER MODEL 286.20-08 MODEL 286.20-10
Maximum Output
Pressure, MPa/PSI
Output Volume
cu. cm/in.
Recommended
Fluids
Maximum Fluid
Temperature
Air Driven Pump
Compressed Air
Requirement
80/12,000
655/40
Refined mineral oil (i.e., PG1¨, or Multitherm¨) or
Silicone oil for triaxial testing to +200
75 °C (165 °F)
Note Many triaxial cells are capable of heating
confining fluid to a temperature exceeding
this value. Therefore, it is imperative that the
fluid be allowed to cool to 75
less, before recirculating it into the Pressure
Intensifier.
0.6 MPa (90 psi), clean and dry
140/20,000
980/60
°C/400 °F
°C/165 °F, o r
18
Introduction
286.20 Pressure Intensifier
Page 19
Operation
This section contains procedures for all operations involving the flow and
pressurization of confining fluid. All operating controls on the Confining
Pressure Intensifier (CPI) are described.
In addition to the Confining Pressure Intensifier, a confining pressure system
typically includes a hydraulic power supply, some type of electronic controller
equipment, and a triaxial cell. Before attempting to operate the CPI, become
familiar with each component of the confining pressure system by reading the
introduction sections of the manuals that apply.
Pressurization and depressurization of confining fluid is primarily under the
control of the electronic controller equipment. Because of the variety of
electronic controller equipment that can be used with a confining pressure
system, information provided in this manual is limited to that which will enable
you to relate CPI parameters, such as fluid pressure and fluid volumetric
displacement, to controller functions such as the command, readout and limit
functions.
A typical procedure for operating the Confining Pressure Intensifier would be:
1. Filling the reservoir; see “Filling the Reservoir From An External Source”
on page 28.
2. Filling the pressure intensifier; see “Filling the Pressure Intensifier From an
External Container” on page 30 and “Filling the Pressure Intensifier From
The Reservoir” on page 32.
3. Filling the triaxial cell; see “Filling the Triaxial Cell” on page 34.
4. Heating the triaxial cell (if applicable); see “Heating The Triaxial Cell” on
page 36.
5. Pressurizing and depressurizing the confining fluid; see “Pressurizing and
Depressurizing The Confining Fluid” on page 37.
6. Cooling the triaxial cell; see “Cooling The Triaxial Cell and Confining
Fluid” on page 41.
7. Emptying the triaxial cell to the reservoir; see “Emptying the Triaxial Cell”
on page 42.
8. Emptying the reservoir to an external container; see “Draining the Reservoir
to an External Location” on page 44.
Before operating the system for the first time, simulate the desired operation.
Locate the controls involved with each step, without actually performing the
adjustment. In this way, you will become familiar with the information that is
required or the decisions that must be made before beginning actual operation.
286.20 Pressure Intensifier Operation
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Page 20
Control Panel
Triaxial
Cell
Open Close
Confining Fluid Input
Open Close
Confining Fluid Output
Open Close
Reservoir Fill
Fluid
Reservoir
Open Close
Intensifier Fill
Pressure
Intensifier
Low Pressure
Relief
Pressure
Transducer
Low pressure line
High pressure line
286.20
Confining
Pressure
Intensifier
r
Fluid Filter
Off
Fluid Transfer Pump Control
Air supply in
100 psi max.
Air Driven
Hydraulic
Pump
Fluid Direction
A
B
C
C
A
B
Empty
Reservoir
From fluid
supply or to
empty fluid
Fill system from
fluid supply
using pump
Fill system
from reservoir
using pump
Confining
Pressure
AB
A
B
Air Direction
Air supply into empty
traxial cell.
Bleed air into reservoir
when filling triaxial cell.
psi
bar
High Pressure
Relief
Air Pressure
Relief
1
2
4
3
5
6
8
7
Control Panel
The following figure shows the operational controls, superimposed on the front
panel hydraulic schematic. The following table describes items 1 through 8,
shown in the figure.
The table lists the operational effects of each individual control. However, note
that performing the various operations listed in the table usually involves the
manipulation of two or more of the controls.
TEM CONTROL FUNCTION
I
1 Confining Fluid
Output
2 Confining Pressure
gage
20
Operation
Adjustable hand-valve. Turning the valve counterclockwise toward Open
allows air to be vented from the triaxial cell to the reservoir when filling the
cell with fluid. The valve must be closed before pressurizing the triaxial cell.
Analog gage. Indicates pressure inside the Triaxial Cell, scaled in pounds
per square inch (psi).
286.20 Pressure Intensifier
Page 21
Control Panel
3 Air Direction
4 Confining Fluid
Input
5 Fluid Direction
6 Fluid Transfer Pump
Control
7 Reservoir Fill
Two position hand-valve. Position “A” enables air to escape from the
triaxial cell to the reservoir when filling the triaxial cell with confining fluid.
Position “B” allows compressed air to force confining fluid from the triaxial
cell to the reservoir, when emptying fluid from the triaxial cell.
(If the valve handle is positioned mid-way between “A” and “B,” the valve
is turned off.)
Adjustable hand-valve. Turning the valve counterclockwise toward Open
allows fluid to flow into or out of the triaxial cell, or it allows cell fluid to be
pressurized by the pressure intensifier. Turning the valve fully clockwise to
Close closes the input to the triaxial cell.
Three position hand valve.
Position “A” allows fluid to flow from the reservoir to the pressure
intensifier or triaxial cell.
Position “B” allows fluid to flow from the reservoir to an external container
when draining the reservoir.
Position “C” allows the air-driven hydraulic pump to pump fluid from an
external container into the reservoir.
Adjustable valve allows compressed air to operate the air-driven hydraulic
pump. (The pump is used only when transferring fluid from one location to
another, not while pressurizing the confining fluid.)
Adjustable hand-valve. Turning the valve counterclockwise toward Open
allows confining fluid to flow from the triaxial cell to the reservoir when
emptying the cell, or from an external container to the reservoir when filling
the reservoir. The valve must be closed before pressurizing the triaxial cell.
8 Intensifier Fill
Adjustable hand-valve. Turning the valve counterclockwise toward Open
allows confining fluid to flow from the reservoir to the pressure intensifier.
The valve must be closed before pressurizing the triaxial cell.
286.20 Pressure Intensifier Operation
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Page 22
High Pressure Precaution
WARNING
CAUTION
High Pressure Precaution
Confining fluid can attain very high pressures. High pressure fluid can
cause severe injury or death.
Ensure pressure gage reads zero before opening the Confining Fluid Output
valve. Follow all procedures provided by this manual.
The Model 286.20 Confining Pressure Intensifier is capable of producing very
high pressures. If mishandled or improperly adjusted, it is capable of seriously
injuring and/or killing personnel, damaging itself, and damaging surrounding
equipment. If care is taken however, the unit can provide prolonged service
without incidents.
High Temperature Precaution
Temperature of fluid in the triaxial cell can exceed the temperature rating of
the Confining Pressure Intensifier. This could damage the Confining
Pressure Intensifier.
Temperature will increase when applying pressure. So if heated to maximum
temperature before pressure is applied, increasing pressure too fast can cause
the temperature to increase to a point where it can damage the equipment;
primarily the transducers.
Also allow fluid in the triaxial cell to cool to 75 °C (167 °F) or less before emptying
the triaxial cell back to the reservoir of the Confining Pressure Intensifier.
The Model 286.20 Confining Pressure Intensifier has a temperature rating of
°C (167 °F). Many triaxial cells have higher temperature ratings. Therefore,
75
the confining fluid in the triaxial cell must be allowed to cool to 75
or below, before being recirculated into the Confining Pressure Intensifier. If
fluid having a temperature higher than 75
the CPI, the acrylic reservoir and associated flexible tubing can be damaged.
°C (167 °F) is allowed to circulate into
°C (167 °F),
22
Operation
286.20 Pressure Intensifier
Page 23
Confining System Operation Considerations
Confining System Operation Considerations
The following paragraphs provide some general information about operation of
the CPI.
Closed-Loop Control Modes Used For Pressurizing Confining Fluid
When pressurizing the confining fluid, the pressure intensifier inside the CPI
operates under closed-loop control principles. External electronic controller
equipment receives signals from a pressure transducer in the CPI, and also from a
linear displacement transducer, which indicates current pressure intensifier piston
position relative to a reference position. The amplitudes of the two signals are
proportional to their respective variables.
Pressure control mode Calibration of the electronic controller equipment is such that the signal from the
pressure transducer relates directly to pressure inside the triaxial cell, in psi or
MPa, depending on how the controller equipment was calibrated. When the
output of the pressure transducer is chosen as a feedback signal for the controller,
pressure becomes the controlled, or independent, variable, and displacement
becomes a dependent, or uncontrolled, variable. This is usually referred to as the
pressure control mode.
Displacement control
mode
The pressure control mode is the preferred control mode.
The signal from the CPI’s linear displacement transducer. When the output of the
displacement transducer is chosen as a feedback signal for the controller,
volumetric displacement becomes the controlled, or independent, variable and
pressure becomes a dependent, or uncontrolled, variable. This is usually referred
to as the displacement control mode.
The displacement control mode is less desirable for use than the pressure control
mode because very small changes in displacement cause very large changes in
pressure. Also, if the displacement control mode were used while the triaxial cell
was being heated, the controller would be insensitive to fluid expansion due to
increasing temperature and very high pressures could result.)
If the triaxial cell is equipped with heaters, it is important to remain aware of the
effects of thermal expansion of the fluid when the Confining Pressure Intensifier
is in operation. This is described under the following heading.
286.20 Pressure Intensifier Operation
23
Page 24
Confining System Operation Considerations
Effects of Thermal Expansion of Confining Fluid
When heaters are used to heat the triaxial cell, the specimen and the confining
fluid, the confining fluid expands.
Thermal expansion
when operating in
pressure control mode
Thermal expansion
when operating in
displacement control
mode
If the confining pressure system is being operated in the pressure control mode
while the triaxial cell is being heated, pressure inside the triaxial cell normally
will not increase as temperature rises. This is because any tendency for pressure
to increase, as a result of thermal expansion or any other cause, will be
automatically corrected by the controller. The piston of the CPI’s pressure
intensifier will simply retract, as required to maintain the correct pressure, in
spite of increasing thermal expansion, assuming that the pressure intensifier’s
piston does not reach the physical end of its stroke in the process. If the piston
cannot retract sufficiently to maintain the programmed pressure, confining
pressure will increase rapidly with further thermal expansion.
If the confining pressure system is being operated in the displacement control
mode, while the triaxial cell is being heated, pressure inside the triaxial cell will
increase rapidly as thermal expansion occurs, because, except for various
monitoring devices such as limit detectors, the controller is insensitive to
pressure changes.
(Properly executed operating procedures can avoid either of the situations that
are described under this heading, where pressure increases undesirably because
of thermal expansion. They are described here to indicate that such situations can
develop and to provide a basis for describing the use of the controller’s error
detectors and limit detectors, which follows.)
24
Operation
286.20 Pressure Intensifier
Page 25
Confining System Operation Considerations
Use of Error Detectors and Limit Detectors While Pressurizing
Information under heading Effects of Thermal Expansion of Confining Fluid
describes two situations in which confining pressure can be, or can become, an
uncontrolled variable. These situations, and actually all “normal” pressurizing
procedures, warrant the use of whatever devices are available, on the electronic
controller equipment, that enable system conditions to be monitored and system
operation to be shut down in the event abnormal or undesirable operating
conditions occur.
In the first situation described under heading Effects of Thermal Expansion of
Confining Fluid, the controller is controlling pressure but is unable to
compensate for additional pressure increase caused by further thermal expansion
because the piston of the pressure intensifier has bottomed out and cannot retract
any further. In this case, two monitoring circuits, common to most controllers,
would afford some protection, if properly pre-adjusted.
Error detectors Error detectors monitor the amplitude of the controller’s error signal
(proportional to the difference between command and feedback) and are
therefore always associated with the controlled variable. In the situation where
the controller becomes unable to compensate for further thermal expansion
(because the pressure intensifier is unable to retract any further), the error signal
will begin to increase in magnitude as soon as the controller can no longer
compensate, if further thermal expansion occurs. If the error detectors had been
adjusted to be sensitive to small error levels, the pressurization procedure would
be terminated very soon after the problem occurred.
Limit detectors Limit detectors can be set up to monitor the level of variables, whether the
variables are independent (controlled) or dependent (uncontrolled). In the first
situation described under heading Effects of Thermal Expansion of Confining
Fluid, the controller’s limit detector could also have been set up to terminate the
pressurization procedure in the event that pressure exceeded some preestablished limit. With both error detectors and limit detectors in use monitoring
the controlled variable, the pressurization procedure would be terminated by
whichever detector reacted first.
In the second situation described under heading Effects of Thermal Expansion of
Confining Fluid, with volumetric displacement the controlled variable, the error
detector could be adjusted to react to some unusual level of error (associated with
the controlled variable, volumetric displacement) and the limit detector could be
set up to actuate if the dependent variable, pressure, exceeded some undesired or
unanticipated level.
Since an unanticipated high pressure level is nearly always of greater concern
than is high volumetric displacement (although a displacement limit could be
caused by a leak, which could be extremely dangerous), pressure should always
be monitored by either limit detectors or error detectors, or both. Limit detectors
provide some advantage over error detectors in that precise limit levels are easily
established. Error detectors actuate when feedback (the actual level of the
controlled variable) deviates from command (the desired level of the controlled
variable) by some presettable amount and they can detect such errors regardless
of the level of the controlled variable. Both detector types offer unique
advantages and should be used simultaneously and judiciously according to the
test situation at hand.
286.20 Pressure Intensifier Operation
25
Page 26
Confining System Operation Considerations
Effects of Air In The System
The operating procedures provided in this section include instructions for
removing air from the pressurized parts of the system before pressurizing the
confining fluid.
A large volume of air can affect system response time, when operating in the
pressure control mode, or it can affect the expected relationship between pressure
and volumetric displacement, when operating in the displacement control mode,
especially when low pressures are involved.
Fluid Capacity Considerations
The CPI’s reservoir has sufficient capacity for normal operation with any MTS
triaxial cell. If the CPI is to be used with pressure vessels requiring greater
capacities, a separate container of confining fluid is usually used.
When a separate fluid storage container is used to increase reservoir capacity
during CPI operating procedures, the container is typically used as the source for
the volume of fluid required to fill the pressure vessel and the CPI’s reservoir is
used as the source for the CPI’s pressure intensifier. When used in this manner,
the CPI’s air-driven hydraulic pump is used to fill the pressure vessel, directly
from the storage container. When the pressure vessel must be emptied, fluid is
forced from the vessel by compressed air applied through the Air Direction
control, although the expelled fluid must first go through the CPI’s reservoir, then
to the external container via the Fluid Direction valve.
Frothing
Certain procedures which involve air flow into the bottom of the fluid reservoir,
such as “Emptying the Triaxial Cell” on page 42, can cause frothing of the fluid
in the reservoir.
Frothing can quickly cause fluid in the reservoir to overflow.
Always observe the reservoir while emptying the triaxial cell and take steps to
avoid overflow:
A. Open the reservoir fill valve one turn, or less.
B. Slow or shut off the flow of air before overflow occurs.
26
Operation
286.20 Pressure Intensifier
Page 27
Operating Procedures
WARNING
The operating procedures, which follow, are presented in the usual order of
occurrence. The first, “Filling the Reservoir From An External Source” on page
28, assumes the reservoir is to be filled for the first time, or that fluid quantity in
the reservoir needs to be replenished. Subsequent procedures assume that the
condition of the system is as established by the successful performance of the
immediately preceding procedure.
Hydraulic power will be applied during some operating procedures.
Conditions hazardous to life and equipment exist on all systems or
equipment that might be connected to the same hydraulic power source.
Before turning on hydraulic power, first make sure that all systems or equipment
that use the same hydraulic power source are in appropriate condition for
application of hydraulic power.
Operating Procedures
Make certain no one is performing work on other systems or equipment sharing
the same hydraulic power source. Inform other people in the vicinity that you are
about to turn on hydraulic power.
286.20 Pressure Intensifier Operation
27
Page 28
Operating Procedures
Filling the Reservoir From An External Source
The following procedure will fill the reservoir from an external fluid container.
The following figure shows the sequence of actions described in the procedure.
Note The fluid to be added must be a recommended type (see “Specifications
and Dimensions” on page 18) and the same as any fluid currently in the
Confining Pressure Intensifier. (Don’t mix fluid types.)
Preliminary steps A. Connect a filler hose between the connector on the lower side of the
Fluid Direction valve (rear side of control panel) and the external fluid
container. Immerse the container end of the hose in the fluid.
B. Connect a source of clean, compressed air to the quick-disconnect
connector on the Fluid Transfer Pump Control (rear of control panel).
Required pressure is 90 psi (0.6 MPa).
Procedure 1. Turn the Fluid Transfer Pump Control fully clockwise to the Off position.
2. Turn the Fluid Direction valve to position C.
3. Turn the Confining Fluid Input valve fully clockwise to the Close position.
4. Turn the Intensifier Fill valve fully clockwise to the Close position.
5. Set the Reservoir Fill valve a turn or two counterclockwise, in the Open
direction.
6. Actuate the air-driven hydraulic pump by rotating the Fluid Transfer Pump
Control counterclockwise.
7. Watch the fluid as it fills the reservoir. Set the Fluid Transfer Pump Control
to the Off position when fluid in the reservoir reaches the desired fill level
(typically three-quarters full).
8. Turn the Reservoir Fill valve fully clockwise (towards Close).
Note It might be desirable to fill the pressure intensifier from the same external
container, next. See “Filling the Pressure Intensifier From an External
Container” on page 30.
28
Operation
286.20 Pressure Intensifier
Page 29
Operating Procedures
Triaxial
Cell
Open Close
Confining Fluid Input
Open Close
Confining Fluid Output
Open Close
Reservoir Fill
Fluid
Reservoir
Open Close
Intensifier Fill
Pressure
Intensifier
Low Pressure
Relief
Pressure
Transducer
Low pressure line
High pressure line
286.20
Confining
Pressure
Intensifier
r
Fluid Filter
Off
Fluid Transfer Pump Control
Air supply in
100 psi max.
Air Driven
Hydraulic
Pump
Fluid Direction
A
B
C
C
A
B
Empty
Reservoir
From fluid
supply or to
empty fluid
Fill system from
fluid supply
using pump
Fill system
from reservoir
using pump
Confining
Pressure
AB
A
B
Air Direction
Air supply into empty
traxial cell.
Bleed air into reservoir
when filling triaxial cell.
psi
bar
High Pressure
Relief
Air Pressure
Relief
4 - Close
5 - Open
8 - Close
2 - C
1 - Off
6 - On
7 - Off
7 - Watch
level
3 - Close
Filling the Reservoir From An External Source
286.20 Pressure Intensifier Operation
29
Page 30
Operating Procedures
Filling the Pressure Intensifier From an External Container
Note This procedure is used only when filling the pressure intensifier for the
first time. It is used after filling the reservoir for the first time and it
purpose is to establish operating fluid levels in the CPI.
For filling the pressure intensifier during daily operation of the CPI, see
“Filling the Pressure Intensifier From The Reservoir” on page 32.
Purpose of this
procedure
If the CPI’s pressure intensifier is being filled for the first time, it may be
desirable to fill it from an external fluid container, as described here, to avoid
lowering the level of fluid in the reservoir, especially when the volumetric
displacement rating of the pressure intensifier is 980 cm
3
), or more.
(80 in.
This procedure fills the pressure intensifier only to the extent allowed by the
position of the pressure intensifier’s piston rod. For example, if the pressure
intensifier’s piston is at mid-stroke, the volume of fluid the pressure intensifier
will be able to contain is approximately half the pressure intensifier’s volumetric
rating. But, the procedure will expel all air from the pressure intensifier and fill
the available space with confining fluid. “Filling the Pressure Intensifier From
The Reservoir” on page 32 describes how to fully fill the pressure intensifier
from the reservoir prior to pressurizing operations.
Note The fluid used must be a recommended type (see Specifications) and
the same as any fluid currently in the CPI. (Don’t mix fluid types.)
3
(60 in.3), or 1300 cm3
Preliminary steps A. Connect a filler hose between the connector on the lower side of the
Fluid Direction valve (rear side of control panel) and the external fluid
container. Immerse the container end of the hose in the fluid.
B. Connect a source of clean, dry compressed air to the quick-disconnect
connector on the Fluid Transfer Pump Control (rear of control panel).
Required pressure is 90 psi (0.7 MPa).
Procedure 1. Turn the Reservoir Fill valve fully clockwise to the Close position.
30
Operation
2. Turn the Confining Fluid Input valve fully clockwise to the Close position.
3. Turn the Fluid Direction valve to the “C” position.
4. Open the Intensifier Fill valve a turn or two counterclockwise.
5. Turn the Fluid Transfer Pump Control counterclockwise just enough to run
the air-driven hydraulic pump at low speed.
6. Watch for air bubbles to stop and/or an increase of fluid level in the
reservoir. When the reservoir fluid level starts to increase beyond its
previous level, turn the Fluid Transfer Pump Control fully clockwise to Off.
7. Put the Fluid Direction valve in the “A” position.
8. Turn the Fluid Transfer Pump Control counterclockwise a turn or two to run
the air-driven pump.
9. When no more bubbles are seen the entering the reservoir, turn the Fluid
Transfer Pump Control fully clockwise to the Off position.
10. Turn the Intensifier Fill valve fully clockwise to the Close position.
286.20 Pressure Intensifier
Page 31
Operating Procedures
Triaxial
Cell
Open Close
Confining Fluid Input
Open Close
Confining Fluid Output
Open Close
Reservoir Fill
Fluid
Reservoir
Open Close
Intensifier Fill
Pressure
Intensifier
Low Pressure
Relief
Pressure
Transducer
Low pressure line
High pressure line
286.20
Confining
Pressure
Intensifier
r
Fluid Filter
Off
Fluid Transfer Pump Control
Air supply in
100 psi max.
Air Driven
Hydraulic
Pump
Fluid Direction
A
B
C
C
A
B
Empty
Reservoir
From fluid
supply or to
empty fluid
Fill system from
fluid supply
using pump
Fill system
from reservoir
using pump
Confining
Pressure
AB
A
B
Air Direction
Air supply into empty
traxial cell.
Bleed air into reservoir
when filling triaxial cell.
psi
bar
High Pressure
Relief
Air Pressure
Relief
4 - Open
10-Close
1 - Close
3 - C
7 - A
5 - On
6 - Off
8 - On
9- Off
6 - Watch
for bubbles
and fluid
level
2 - Close
Filling the Pressure Intensifier From an External Container
286.20 Pressure Intensifier Operation
31
Page 32
Operating Procedures
Filling the Pressure Intensifier From The Reservoir
Note If you are filling the pressure intensifier for the first time, perform the
procedure under heading “Filling the Pressure Intensifier From an
External Container” on page 30. This procedure is used for normal, day-
to day use prior to pressurizing operations.
Purpose of this
procedure
The purpose of this procedure is to establish three simultaneous conditions in
preparation for pressurizing the confining fluid:
A. To fill the high pressure end of the pressure intensifier with confining
fluid.
B. To expel all air from the high pressure end of the pressure intensifier.
C. To place the pressure intensifier’s piston near the start of its
displacement range
Procedure 1. Make sure the Reservoir Fill valve is turned fully clockwise to the Close
position.
2. Open the Intensifier Fill valve a turn or two counterclockwise.
3. Turn the Confining Fluid Input valve fully clockwise to Close.
4. Configure the confining system’s controller for the displacement control
mode.
5. At the CPI’s control equipment, turn on hydraulic pressure.
6. At the displacement controller, cause the pressure intensifier’s piston rod to
slowly stroke to the lower end of it’s travel (piston fully retracted, zero
displacement position). This will draw fluid from the reservoir, into the
pressure intensifier.
32
Operation
7. Actuate the air-driven hydraulic pump by rotating the Fluid Transfer Pump
Control counterclockwise.
8. Watch the reservoir and note any air bubbles escaping from the intensifier.
When the air bubbles cease, set the Fluid Transfer Pump Control to the Off
position.
9. At the displacement controller, cause the pressure intensifier’s piston rod to
stroke slowly
action forces any air out of the intensifier lines. When air bubbles cease to
appear, stop the motion of the pressure intensifier’s piston rod.
10. At the displacement controller, cause the pressure intensifier’s piston rod to
stroke slowly downward again to about 10% of its displacement range. This
will draw fluid back into the pressure intensifier.
11. Turn the Intensifier Fill valve fully clockwise to Close.
12. Turn off hydraulic power.
upward while observing the reservoir for air bubbles. This
286.20 Pressure Intensifier
Page 33
Operating Procedures
Triaxial
Cell
Open Close
Confining Fluid Input
Open Close
Confining Fluid Output
Open Close
Reservoir Fill
Fluid
Reservoir
Open Close
Intensifier Fill
Pressure
Intensifier
Low Pressure
Relief
Pressure
Transducer
Low pressure line
High pressure line
286.20
Confining
Pressure
Intensifier
r
Fluid Filter
Off
Fluid Transfer Pump Control
Air supply in
100 psi max.
Air Driven
Hydraulic
Pump
Fluid Direction
A
B
C
C
A
B
Empty
Reservoir
From fluid
supply or to
empty fluid
Fill system from
fluid supply
using pump
Fill system
from reservoir
using pump
Confining
Pressure
AB
A
B
Air Direction
Air supply into empty
traxial cell.
Bleed air into reservoir
when filling triaxial cell.
psi
bar
High Pressure
Relief
Air Pressure
Relief
2 - Open
11-Close
1 - Close
7 - On
8 - Off
Steps 4 through 6, 9, and 10 are
performed on the test controller
and not shown here
3 - Close
Filling the Pressure Intensifier From The Reservoir
286.20 Pressure Intensifier Operation
33
Page 34
Operating Procedures
Filling the Triaxial Cell
Note Before starting this procedure, decide whether the triaxial cell (or
Preliminary step A. If you are filling the triaxial cell from an external container, connect a
Procedure 1. Set the Fluid Direction valve to the desired source of confining fluid:
• Position “A” selects fluid from the reservoir.
• Position “C” selects fluid from the external container.
2. Turn the Reservoir Fill valve fully clockwise to Close.
3. Turn the Intensifier Fill valve fully clockwise to Close.
pressure vessel) will be filled from the reservoir or from an external fluid
container. See Heading 2.5.5. Normal operating procedure when
operating with an MTS triaxial cell, is to fill the triaxial cell from the CPI’s
fluid reservoir.
filler hose between the connector on the lower side of the Fluid
Direction valve (rear side of control panel) and the external fluid
container. Immerse the container end of the hose in the fluid.
4. Turn the Confining Fluid Input valve a turn or two counterclockwise to
Open.
5. Turn the Confining Fluid Output valve a turn or two counterclockwise to
Open.
6. Open the confining fluid valve on the triaxial cell. See the lower sketch in
the following figure. (The CPI’s Confining Fluid Input valve is connected
by high pressure hose to the triaxial cells lower confining fluid valve. The
CPI’s Confining Fluid Output valve is connected to the triaxial cell’s
pressure relief valve.)
7. Set the Air Direction valve to position A.
8. Actuate the air-driven hydraulic pump by rotating the Fluid Transfer Pump
Control counterclockwise. Watch the reservoir. Regulate the speed of the
air-driven pump to avoid frothing of the fluid in the reservoir. Excessive
frothing can cause fluid to overflow from the reservoir (on early CPI
versions only).
Note Fluid will flow into the triaxial cell, forcing air out to the reservoir.
On later CPI versions, the line from the Air Direction control expels air/
fluid into the reservoir from above the reservoir’s fluid level -- watch for
bubble-free fluid to flow into the reservoir. On earlier CPI versions the
line from the Air Direction control enters into the bottom of the reservoir -
- watch for the bubble stream to stop flowing.
34
Operation
9. Watch for fluid flow into the reservoir and note any air bubbles. When air
bubbles cease to appear, turn the Fluid Transfer Pump Control to the Off
position.
286.20 Pressure Intensifier
Page 35
Triaxial
Cell
Open Close
Confining Fluid Input
Open Close
Confining Fluid Output
Open Close
Reservoir Fill
Fluid
Reservoir
Open Close
Intensifier Fill
Pressure
Intensifier
Low Pressure
Relief
Pressure
Transducer
Low pressure line
High pressure line
286.20
Confining
Pressure
Intensifier
r
Fluid Filter
Off
Fluid Transfer Pump Control
Air supply in
100 psi max.
Air Driven
Hydraulic
Pump
Fluid Direction
A
B
C
C
A
B
Empty
Reservoir
From fluid
supply or to
empty fluid
Fill system from
fluid supply
using pump
Fill system
from reservoir
using pump
Confining
Pressure
AB
A
B
Air Direction
Air supply into empty
traxial cell.
Bleed air into reservoir
when filling triaxial cell.
psi
bar
High Pressure
Relief
Air Pressure
Relief
3 - Close
2 - Close
8 - On
9 - Off
4 - Open
Filling the Triaxial Cell
1 - A
or C
5 - Open
9 - Watch
for bubbles
and fluid
level
6 - Open the
confining
pressure
valve
7 - A
Operating Procedures
286.20 Pressure Intensifier Operation
35
Page 36
Operating Procedures
WARNING
Heating The Triaxial Cell
Some users choose to heat the triaxial cell before applying test pressures to the
cell. Others apply test pressures while the cell is heating. In either case, the CPI
must be operated in pressure control mode during the heating process. Also, the
Confining Fluid Output valve on the CPI’s front panel should be closed to
prevent hot fluid from entering, and damaging, the reservoir.
Pressure inside the triaxial cell could reach high levels while the cell is
being heated.
This could cause personal injury or death or damage to the equipment or
specimen.
Always operate the CPI in pressure control mode during the heating process.
The process of heating the triaxial cell is included as a step in the following
procedure (“Pressurizing and Depressurizing The Confining Fluid” on page 37).
36
Operation
286.20 Pressure Intensifier
Page 37
Operating Procedures
WARNING
Pressurizing and Depressurizing The Confining Fluid
This procedure describes how to pressurize and depressurize the triaxial cell and
indicates the proper time to heat and cool the triaxial cell.
Purpose of this
procedure:
This procedure describes how (and when):
A. To make sure the pressure intensifier’s piston is properly positioned for
pressurizing the triaxial cell.
B. To heat and pressurize the triaxial cell.
C. To cool and depressurize the triaxial cell at the end of the test.
Note This procedure requires that hydraulic pressure be applied to the
pressure intensifier’s servovalve to enable the pressure intensifier’s
piston to be stroked under closed loop control. Explicit instructions
cannot be provided for these steps because of the large variety of
electronic controller equipment in use. Refer to the system operation
manual.
Hydraulic power will be applied during this procedure.
Conditions that can be hazardous to life and equipment can exist on all
systems or equipment that are connected to the same hydraulic power
source.
Before turning on hydraulic power, make sure that all systems or equipment that
use the same hydraulic power source are in an appropriate condition before you
turn on hydraulic power.
Make certain no one is performing work on other systems or equipment that share
the same hydraulic power source as the CPI. If people are working on other
systems or equipment, inform them that you intend to turn on hydraulic power.
Inform other people in the vicinity that you are about to turn on hydraulic power.
286.20 Pressure Intensifier Operation
37
Page 38
Operating Procedures
WARNING
Procedure: 1. Configure the confining pressure system’s controller for the displacement
control mode. (The pressure control mode will be used later while
pressurizing the triaxial cell.)
to position the pressure
intensifier’s piston
2. On the triaxial cell, close the lower confining pressure valve. (Leave the
triaxial cell’s upper valve open.)
3. On the CPI, open the Intensifier Fill valve.
4. Make sure the CPI’s Reservoir Fill valve is fully clockwise to the Close
position.
5. At the CPI’s electronic control equipment, turn on low hydraulic pressure.
6. At the CPI’s displacement controller, adjust the position of the pressure
intensifier’s piston for 10% displacement.
Placing the piston at 10% displacement allows a 10% margin for piston
retraction, if required, while still providing a 90% displacement stroke, if
necessary, while pressurizing the triaxial cell.
7. Close the CPI’s Intensifier Fill valve.
High hydraulic pressure will be applied during the following steps.
Conditions that may be hazardous to life and equipment can exist on all
systems or equipment that are connected to the same hydraulic power
source.
pressurizing the
triaxial cell
Steps 9 and 10 provide some information about how to minimize the hazards of
turning on high hydraulic pressure. However because of the variety of electronic
controller equipment in use, explicit instructions cannot be given here.
8. On the electronic control equipment, perform the operations necessary to
switch from displacement control mode to pressure control mode.
With certain types of electronic control equipment, it might be necessary to
turn off hydraulic power while converting to pressure control mode. Other
equipment types allow manual mode switching with hydraulic power on
and, if a computer is included, via the keyboard. Refer to your test controller
documentation.
9. On the triaxial cell, open the lower confining pressure valve.
10. On the CPI, make sure the Confining Fluid Input valve is open.
11. If the triaxial cell is to be heated, set up the temperature controller
equipment as required to bring the triaxial cell to operating temperature.
This process will usually take at least several hours, depending on the
temperature to be reached.
38
Operation
286.20 Pressure Intensifier
Page 39
Operating Procedures
12. On the CPI’s pressure controller, perform the operations necessary to bring
triaxial cell confining pressure to test level.
The CPI’s confining pressure gage will provide an approximate indication of
confining pressure but the readout capabilities of the CPI’s electronic controller
should by used where any precision is required.
cooling and
depressurizing the
triaxial cell
13. After the test is over, perform the operations necessary at the CPI’s pressure
controller to reduce triaxial cell confining pressure to a low level.
14. If the triaxial cell has been heated, adjust the temperature controller
equipment to allow the triaxial cell to cool. See “Cooling The Triaxial Cell
and Confining Fluid” on page 41. It will take several hours for the triaxial
cell to cool, depending on the temperature of the triaxial cell.
15. After the triaxial cell has cooled to, at most, 167°F (75°C), perform the
operations necessary at the CPI’s pressure controller to reduce triaxial cell
confining pressure to zero.
16. After you are certain that confining pressure has been reduced to zero, turn
the Confining Pressure Input valve fully clockwise to Close.
17. At the electronic controller equipment, turn off hydraulic power to the CPI.
18. Slowly open the CPI’s Confining Pressure Output valve to vent residual
pressure, if any, from the triaxial cell.
286.20 Pressure Intensifier Operation
39
Page 40
Operating Procedures
Triaxial
Cell
Open Close
Confining Fluid Input
Open Close
Confining Fluid Output
Open Close
Reservoir Fill
Fluid
Reservoir
Open Close
Intensifier Fill
Pressure
Intensifier
Low Pressure
Relief
Pressure
Transducer
Low pressure line
High pressure line
286.20
Confining
Pressure
Intensifier
r
Fluid Filter
Off
Fluid Transfer Pump Control
Air supply in
100 psi max.
Air Driven
Hydraulic
Pump
Fluid Direction
A
B
C
C
A
B
Empty
Reservoir
From fluid
supply or to
empty fluid
Fill system from
fluid supply
using pump
Fill system
from reservoir
using pump
Confining
Pressure
AB
A
B
Air Direction
Air supply into empty
traxial cell.
Bleed air into reservoir
when filling triaxial cell.
psi
bar
High Pressure
Relief
Air Pressure
Relief
3 - Open
7 - Close
4 - Close
10 - Open
16 - Close
Pressurizing and Depressurizing The Confining Fluid
18 - Open
2 - Close the
confining
pressure
valve
9 - Open the
confining
pressure
valve
Operation
40
286.20 Pressure Intensifier
Page 41
Cooling The Triaxial Cell and Confining Fluid
CAUTION
Triaxial
Cell
Open Close
Confining Fluid Input
Open Close
Confining Fluid Output
Open Close
Reservoir Fill
Fluid
Reservoir
Open Close
Intensifier Fill
Pressure
Intensifier
Low Pressure
Relief
Pressure
Transducer
Low pressure line
High pressure line
286.20
Confining
Pressure
Intensifier
r
Fluid Filter
Off
Fluid Transfer Pump Control
Air supply in
100 psi max.
Air Driven
Hydraulic
Pump
Fluid Direction
A
B
C
C
A
B
Empty
Reservoir
From fluid
supply or to
empty fluid
Fill system from
fluid supply
using pump
Fill system
from reservoir
using pump
Confining
Pressure
AB
A
B
Air Direction
Air supply into empty
traxial cell.
Bleed air into reservoir
when filling triaxial cell.
psi
bar
High Pressure
Relief
Air Pressure
Relief
Cooling the Triaxial Cell and Confining Fluid
CAUTION
Do not allow hot fluid (above 167°F (75°C)
to be recirculated back into the CPI.
Temperature of fluid in the triaxial cell can exceed the temperature rating of
the Confining Pressure Intensifier.
This could damage the Confining Pressure Intensifier.
Always allow fluid in the triaxial cell to cool to 167∞F (75∞C) or less before
emptying the triaxial cell back to the reservoir of the Confining Pressure
Intensifier.
The CPI has a temperature rating of 167°F (75°C). Many triaxial cells have
higher temperature ratings. Confining fluid in the triaxial cell must be allowed to
cool to 167°F (75°C), or below, before being recirculated into the Confining
Pressure Intensifier. If fluid having a temperature higher than 167°F (75°C) is
allowed to circulate into the CPI, the acrylic reservoir and associated flexible
tubing can be damaged.
Operating Procedures
There are no operational steps involved in allowing the triaxial cell and its
confining fluid to cool. Do not operate the CPI or cause hot fluid to flow into the
CPI while the triaxial cell is cooling.
286.20 Pressure Intensifier Operation
41
Page 42
Operating Procedures
CAUTION
Emptying the Triaxial Cell
Temperature of fluid in the triaxial cell may exceed the temperature rating of
the Confining Pressure Intensifier.
This could damage the Confining Pressure Intensifier
Always allow fluid in the triaxial cell to cool to 167∞F (75∞C) or less before
emptying the triaxial cell back to the reservoir of the Confining Pressure
Intensifier.
Procedure: 1. Verify that the triaxial cell has cooled to 167°F (75°C) or less.
2. Make sure the Air Direction valve is in position “A”.
3. Adjust the electronic controller equipment to reduce pressure in the triaxial
cell to a small, but positive, pressure (e.g., 10 psi).
4. Open the Confining Fluid Output valve one turn.
The pressure intensifier will extend to the end of its stroke as fluid is expelled
from the pressure intensifier, up through the triaxial cell and into the reservoir.
Leave hydraulic power applied to the CPI, with the pressure intensifier fully
extended.
5. Open the Reservoir Fill valve one turn only.
Note Be prepared to perform step 8 and 9 immediately after step 7, in order to
avoid frothing and overflow of fluid from the reservoir.
6. Turn the Air Direction valve to the “B” position.
Compressed air applied to the top of the cell will cause fluid to flow from the
cell, up through the Reservoir Fill valve and into the reservoir.
7. When the reservoir is about half full, turn the Air Direction valve to the
neutral or off position (valve handle pointing straight up.)
Remaining air pressure in the cell will continue to empty the cell.
8. Watch for the first air bubbles to enter the reservoir (from the bottom) and,
when bubbles are seen, immediately
turn the Reservoir Fill valve off to
avoid frothing and overflow of fluid from the reservoir.
42
Operation
9. Bleed any remaining air pressure from the cell by turning the Air Direction
valve to the “A” position.
286.20 Pressure Intensifier
Page 43
Operating Procedures
Triaxial
Cell
Open Close
Confining Fluid Input
Open Close
Confining Fluid Output
Open Close
Reservoir Fill
Fluid
Reservoir
Open Close
Intensifier Fill
Pressure
Intensifier
Low Pressure
Relief
Pressure
Transducer
Low pressure line
High pressure line
286.20
Confining
Pressure
Intensifier
r
Fluid Filter
Off
Fluid Transfer Pump Control
Air supply in
100 psi max.
Air Driven
Hydraulic
Pump
Fluid Direction
A
B
C
C
A
B
Empty
Reservoir
From fluid
supply or to
empty fluid
Fill system from
fluid supply
using pump
Fill system
from reservoir
using pump
Confining
Pressure
AB
A
B
Air Direction
Air supply into empty
traxial cell.
Bleed air into reservoir
when filling triaxial cell.
psi
bar
High Pressure
Relief
Air Pressure
Relief
5 - Open (one turn)
8 - Watch for bubbles
8 - Close
Emptying the Triaxial Cell
7 - Watch
the reservoir
2 - A
6 - C
7 - Off
9 - A
4 - Open
(one turn)
286.20 Pressure Intensifier Operation
43
Page 44
Operating Procedures
Triaxial
Cell
Open Close
Confining Fluid Input
Open Close
Confining Fluid Output
Open Close
Reservoir Fill
Fluid
Reservoir
Open Close
Intensifier Fill
Pressure
Intensifier
Low Pressure
Relief
Pressure
Transducer
Low pressure line
High pressure line
286.20
Confining
Pressure
Intensifier
r
Fluid Filter
Off
Fluid Transfer Pump Control
Air supply in
100 psi max.
Air Driven
Hydraulic
Pump
Fluid Direction
A
B
C
C
A
B
Empty
Reservoir
From fluid
supply or to
empty fluid
Fill system from
fluid supply
using pump
Fill system
from reservoir
using pump
Confining
Pressure
AB
A
B
Air Direction
Air supply into empty
traxial cell.
Bleed air into reservoir
when filling triaxial cell.
psi
bar
High Pressure
Relief
Air Pressure
Relief
Draining the Reservoir To An External Container
2 - B
Draining the Reservoir to an External Location
Procedure: 1. Connect a hose between the connector on the lower side of the Fluid
Direction valve (rear side of control panel) and the external fluid container.
2. Set the Fluid Direction valve to position B. Confining fluid in the fluid
reservoir will flow into the container by means of gravity.
Operation
44
286.20 Pressure Intensifier
Page 45
Page 46
m
MTS Systems Corporation
14000 Technology Drive
Eden Prairie, Minnesota 55344-2290 USA
Toll Free Phone: 800-328-2255
(within the U.S. or Canada)
Phone: 952-937-4000
(outside the U.S. or Canada)
Fax: 952-937-4515
E-mail: info@mts.com
http://www.mts.com
ISO 9001:2000 Certified QMS
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