Series 111 Accumulator Product Information
Model 111.11 Model 111.12
011-553-304 D be certain.
© 2013 MTS Systems Corporation. All rights reserved.
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may be protected in other countries.
All other trademarks or service marks are property of their respective owners.
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retained by MTS and granted to the End User. All Software is proprietary, confidential, and owned by MTS
Systems Corporation and cannot be copied, reproduced, disassembled, decompiled, reverse engineered,
or distributed without express written consent of MTS.
MTS software is developed using established quality practices in accordance with the requirements detailed
in the ISO 9001 standards. Because MTS-authored software is delivered in binary format, it is not user
accessible. This software will not change over time. Many releases are written to be backwards compatible,
creating another form of verification. The status and validity of the MTS operating software is also checked
during system verification and routine calibration of MTS hardware. These controlled calibration processes
compare the final test results after statistical analysis against the predicted response of the calibration
standards. With these established methods, MTS assures its customers that MTS products meet exacting
quality standards when initially installed and will continue to perform as intended over time.
Contents
1.0 Technical Support 5
2.0 Preface 9
3.0 Introduction 13
4.0 Safety 21
1.1.0 How to Get Technical Support........................................................................................................5
1.2.0 Before You Contact MTS................................................................................................................5
1.3.0 If You Contact MTS by Phone........................................................................................................7
1.4.0 Problem Submittal Form in MTS Manuals.....................................................................................8
2.1.0 Before You Begin............................................................................................................................9
2.2.0 Documentation Conventions...........................................................................................................9
3.1.0 Introduction...................................................................................................................................14
3.2.0 What you need to know.................................................................................................................14
3.3.0 Functional Description..................................................................................................................15
3.4.0 Series 111 Accumulator Specications.........................................................................................16
4.1.0 Hazard Placard Placement.............................................................................................................22
5.0 Installation 25
5.1.0 About the Series 111 Accumulator Installation Procedure............................................................26
5.1.1.0 Series 111 Accumulator Installation Procedure.............................................................27
6.0 Maintenance 29
6.1.0 Series 111 Accumulator Maintenance Guidelines.........................................................................30
6.2.0 Check the Accumulator Precharge................................................................................................32
6.2.1.0 Check the Series 111 Accumulator Precharge................................................................34
6.2.2.0 Check a Non-MTS Accumulator Precharge...................................................................34
6.3.0 About Changing the Precharge Pressure.......................................................................................35
6.3.1.0 Decrease the Precharge Pressure....................................................................................35
6.3.2.0 Increase the Precharge Pressure.....................................................................................36
6.4.0 Purge Fluid from the Gas Chamber...............................................................................................37
6.5.0 Remove the Accumulator..............................................................................................................38
Series 111 Accumulator Product Information 3
1.0 Technical Support
1.1.0 How to Get Technical Support
Start with your manuals
The manuals supplied by MTS provide most of the inf ormation you need to use and maintain your equipment.
If your equipment includes software, look for online help and README files that contain additional product
information.
Technical support methods
MTS provides a full range of support services after your system is installed. If you ha ve any questions about
a system or product, contact Technical Support in one of the following ways.
Web site
Outside the U.S.
For technical support outside the United States, contact your local sales and service office. For a list of
worldwide sales and service locations and contact information, use the Global MTS link at the MTS web site:
www.mts.com > Global Presence > Choose a Region
www.mts.com > Contact Us (upper-right corner) > In the Subject field, choose
To escalate a problem; Problem Submittal Form
Worldwide: tech.support@mts.comE-mail
Europe: techsupport.europe@mts.com
Worldwide: 1 800 328 2255 - toll free in U.S.; +1 952 937 4000 - outside U.S.Telephone
Europe: +800 81002 222, International toll free in Europe
1.2.0 Before You Contact MTS
MTS can help you more efficiently if you have the following information available when you contact us for
support.
Series 111 Accumulator Product Information 5
Know your site number and system number
The site number contains your company number and identifies y our equipment type (such as material testing
or simulation).The number is typically written on a label on your equipment before the system leaves MTS.
If you do not know your MTS site number, contact your sales engineer.
Example site number: 571167
When you have more than one MTS system, the system job number identifies your system.You can find
your job number in your order paperwork.
Example system number: US1.42460
Know information from prior technical assistance
If you have contacted MTS about this problem before, we can recall your file based on the:
• MTS notification number
• Name of the person who helped you
Identify the problem
Describe the problem and know the answers to the following questions:
• How long and how often has the problem occurred?
• Can you reproduce the problem?
• Were any hardware or software changes made to the system before the problem started?
• What are the equipment model numbers?
• What is the controller model (if applicable)?
• What is the system configuration?
Know relevant computer information
For a computer problem, have the following information available:
• Manufacturer’s name and model number
• Operating software type and service patch information
• Amount of system memory
• Amount of free space on the hard drive where the application resides
• Current status of hard-drive fragmentation
• Connection status to a corporate network
Know relevant software information
For software application problems, have the following information available:
• The software application’s name , v ersion number, build number, and (if availab le) software patch n umber .
This information can typically be found in the About selection in the Help menu.
• The names of other applications on your computer, such as:
• Anti-virus software
• Screen savers
6 Series 111 Accumulator Product Information
• Keyboard enhancers
• Print spoolers
• Messaging applications
1.3.0 If You Contact MTS by Phone
A Call Center agent registers your call before connecting you with a technical support specialist. The agent
asks you for your:
• Site number
• Name
• Company name
• Company address
• Phone number where you can be reached
If your issue has a notification number, please provide that number. A new issue will be assigned a unique
notification number.
Identify system type
To enable the Call Center agent to connect you with the most qualified technical support specialist available,
identify your system as one of the following types:
• Electrodynamic material test system
• Electromechanical material test system
• Hydromechanical material test system
• Vehicle test system
• Vehicle component test system
• Aero test system
Be prepared to troubleshoot
Prepare to perform troubleshooting while on the phone:
• Call from a telephone close to the system so that you can implement 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.
Write down relevant information
In case Technical Support must call you:
• Verify the notification number.
• Record the name of the person who helped you.
Series 111 Accumulator Product Information 7
• Write down any specific instructions.
After you call
MTS logs and tracks all calls to ensure that you receive assistance for your problem or request. If you have
questions about the status of your problem or have additional information to report, please contact Technical
Support again and provide your original notification number.
1.4.0 Problem Submittal Form in MTS Manuals
Use the Problem Submittal Form to communicate problems with y our software, hardware, man uals, or service
that are not resolved to your satisfaction through the technical support process.The form includes check
boxes that allo w you to indicate the urgency of y our problem and y our e xpectation of an acceptable response
time.We guarantee a timely response—your feedback is important to us.
You can access the Problem Submittal Form at www.mts.com > Contact Us (upper-right corner) > In the
Subject field, choose To escalate a problem; Problem Submittal Form
8 Series 111 Accumulator Product Information
2.0 Preface
2.1.0 Before You Begin
Safety first!
Before you use y our MTS product or system, read and understand the safety information provided with your
system. Improper installation, operation, or maintenance can result in hazardous conditions that can cause
severe personal injury or death, or damage to your equipment and specimen. Again, read and understand
the safety information provided with your system before you continue. It is very important that you remain
aware of hazards that apply to your system.
Other MTS manuals
In addition to this manual, you may receive additional manuals in paper or electronic form.
You may also receive an MTS System Documentation CD. It contains an electronic copy of the manuals that
pertain to your test system.
Controller and application software manuals are typically included on the software CD distribution disc(s).
2.2.0 Documentation Conventions
The following paragraphs describe some of the conventions that are used in your MTS manuals.
Hazard conventions
Hazard notices may be embedded in this manual.These notices contain safety information that is specific
to the activity to be performed. Hazard notices immediately precede the step or procedure that may lead to
an associated hazard. Read all hazard notices carefully and f ollow all directions and recommendations.Three
different levels of hazard notices may appear in your manuals. Following are examples of all three levels.
(for general safety information, see the safety information provided with your system.)
DANGER:
Danger notices indicate the presence of a hazard with a high level of risk which, if
ignored, will result in death, severe personal injury, or substantial property damage.
WARNING:
Warning notices indicate the presence of a hazard with a medium lev el of risk which,
if ignored, can result in death, severe personal injury, or substantial property damage.
Series 111 Accumulator Product Information 9
CAUTION:
Caution notices indicate the presence of a hazard with a low level of risk which, if
ignored, could cause moderate or minor personal injury or equipment damage, or
could endanger test integrity.
Other special text conventions
Important:
Important notices provide information about your system that is essential to its proper
function.While not safety-related, if the important information is ignored, test results may
not be reliable, or your system may not operate properly.
Note:
Notes provide additional information about operating your system or highlight easily
overlooked information.
Recommended:
Recommended notes provide a suggested way to accomplish a task based on what MTS
has found to be most effective.
Tip:
Tips provide helpful information or a hint about how to most efficiently accomplish a task.
Access:
Access provides the route you should follow to a referenced item in the software.
Example:
Examples show specific scenarios relating to your product and appear with a shaded
background.
Special terms
The first occurrence of special terms is shown in italics.
Illustrations
Illustrations appear in this manual to clarify text.They 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.
10 Series 111 Accumulator Product Information
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 clic k a hypertext link,
the application jumps to the corresponding topic.
Series 111 Accumulator Product Information 11
3.0 Introduction
Topics:
•
Introduction............................................................................................................................................14
•
What you need to know.........................................................................................................................14
•
Functional Description...........................................................................................................................15
•
Series 111 Accumulator Specifications..................................................................................................16
Series 111 Accumulator Product Information 13
3.0 Introduction
3.1.0 Introduction
The MTS Series 111 Accumulators stabilize the hydraulic lines in y our system.There are two models availab le:
• The Model 111.11B Accumulator is a boss port-mounted accumulator that requires a boss adapter fitting
for mounting.
• The Model 111.12C Accumulator is bolt-mounted to a flange and typically has a larger nitrogen gas capacity
than the Model 111.11B.
3.2.0 What you need to know
MTS Systems Corporation assumes that you know how to use your controller. See the appropriate manual
for information about performing any controller-related step in this manual's procedures.You are expected
to know how to perform the following procedure:
• Turn hydraulic pressure on and off
• Select a control mode
• Manually adjust the actuator position
14 Series 111 Accumulator Product Information
3.0 Introduction
3.3.0 Functional Description
Series 111 Accumulators can reduce fluctuations in hydraulic lines due to sudden changes in hydraulic flow
rate.They also act as a short-term energy source for high-rate tests by providing additional hydraulic flo w f or
short periods to meet irregular peak demands. Like a capacitor , accumulators filter out pulses in the h ydraulic
fluid to provide steady hydraulic pressure.
Accumulators are like a hydr aulic version of a capacitor .They are h ydro-pneumatic devices located at strategic
points in a hydraulic system.They may be connected to the pressure line and to the return line.
Accumulator
DescriptionItem
Nitrogen Side1
Piston2
Fluid Side3
Hydraulic Fluid4
Accumulators are precharged with pressure. Precharge pressure is the pressure of the compressed gas
(usually nitrogen) before hydraulic fluid is introduced.
Inserting accumulators into the hydraulic lines permits some fluid to be stored under pressure a short distance
from the servovalve and actuator. This has the effect of keeping fluid in the lines in motion and reducing the
inertia and line restriction considerations.When the servovalve opens and line pressure begins to drop, the
accumulator in the hydraulic service manifold (HSM) immediately supplies part of the fluid volume and
maintains the line pressure.Then, when the servovalve closes , the hydraulic power supply (HPS) recharges
the accumulator, causing fluid in the lines to remain in motion.
The pattern and frequency of the signal that drives the servovalve will have considerable effect on the HSM
accumulator efficiency. Square wave signals, for example, cause a greater demand than sine wave signals
or ramp signals.
Series 111 Accumulator Product Information 15
3.0 Introduction
At some frequencies, fluid flow in the lines may stop completely, and overcoming the fluid inertia may become
a more significant operational factor.
An accumulator in the return line damps the pulsing effect caused by “slugs” of fluid being injected into the
line as the actuator moves. Movement of hoses or hammering of hard lines is also reduced.
3.4.0 Series 111 Accumulator Specifications
The following tables list the specifications for the Series 111 Accumulators.
Product Specifications
Model 111.12CModel 111.11BParameter
138 MPa (20,000 psi)83 MPa (12,000 psi)Minimum burst pressure
22 MPa (3200 psi)21 MPa (3000 psi)Rated fatigue pressure
–40°C to 93.3°C (–40°F to 200°F)Operating temperature
Petroleum-based hydraulic fluid. Contact MTS for use with other fluids.Hydraulic fluid
Dry nitrogenDry nitrogen
Note:
Specifications are subject to change without notice. Contact MTS Systems Corporation for v erification
of specifications critical to your needs.
Capacity, Dimension, and Weight
Model
*
Nitrogen Gas
Capacity
Length
†
†
A
†
B
Fluid Port
MaxpHydraulic
Connection
cm (in.)cm (in.)
kg (lbs)cm
(in.)
111.11B-01
82 cm3 (5 in.3)
7.87 (3.1)15.54 (6.12)
6.35
(2.5)
12 SAE
(1-1/16-12
4.26
(9.4)
UNF-2B)
*
The models listed in this table are considered standard models. Other models may be manufactured with
different capacities, lengths, or hydraulic fluid port connections than listed here. Contact MTS Systems
Corporation for information on nonstandard models.
†
See the related cross-section figures.
‡
Standard pressure series (Code 61).
16 Series 111 Accumulator Product Information
3.0 Introduction
*
Model
111.11B-02
111.11B-03
111.11B-04
111.12C-02
Nitrogen Gas
Capacity
164 cm3 (10
in.3)
475 cm3 (1 pt)
950 cm3 (1 qt)
950 cm3 (1 qt)
Length
†
†
A
†
B
Fluid Port
MaxpHydraulic
Connection
cm (in.)cm (in.)
kg (lbs)cm
(in.)
7.87 (3.1)18.08 (7.12)
6.35
(2.5)
12 SAE
(1-1/16-12
4.63
(10.2)
UNF-2B)
7.87 (3.1)27.94 (11.0)
6.35
(2.5)
16 SAE
(1-5/16-12
5.94
(13.1)
UNF-2B)
7.87 (3.1)42.88 (16.9)
6.35
(2.5)
20 SAE
(1-5/8-12
7.98
(17.6)
UNF-2B)
‡
‡
18.45
(40.6)
21.77
(48.0)
12.7 (5.0)29.51 (11.6)
10.16
(4.0)
12.7 (5.0)39.07 (15.4)1.9 l (0.5 gal)111.12C-03
10.16
(4.0)
1-1/2 SAE
4-bolt flange
1-1/2 SAE
4-bolt flange
12.7 (5.0)61.93 (24.4)3.8 l (1 gal)111.12C-04
10.16
(4.0)
1-1/2 SAE
4-bolt flange
‡
The following cross-section figures illustrate the difference between the accumulator models.
29.87
65.8
Model 111.11B Accumulator Cross-Section
Series 111 Accumulator Product Information 17
3.0 Introduction
DescriptionItem
1.563 in. (39.7 mm)1
Length2
Typical Boss Adapter Fitting3
Locking Pin4
Hydraulic Fluid Port5
Relief Vent6
Accumulator Valve Assembly7
Protective Cover8
Model 111.12C Accumulator Cross-Section
DescriptionItem
1.563 in. (39.7 mm)1
Length2
1.406 in. (35.7 mm)3
0.703 in. (17.8 mm)4
2.750 in. (69.9 mm)5
1.375 in. (34.9 mm)6
1/2-13UNC 2B7
Locking Pin8
18 Series 111 Accumulator Product Information
3.0 Introduction
DescriptionItem
Hydraulic Fluid Port9
Relief Vent10
Accumulator Valve Assembly11
Protective Cover12
Series 111 Accumulator Product Information 19
4.0 Safety
Topics:
•
Hazard Placard Placement....................................................................................................................22
Series 111 Accumulator Product Information 21
4.0 Safety
4.1.0 Hazard Placard Placement
Hazard placards contain specific safety information and are affixed directly to the system so they are plainly
visible.
Each placard describes a system-related hazard.When possible, international symbols (icons) are used to
graphically indicate the type of hazard and the placard label indicates its severity. In some instances, the
placard may contain text that describes the hazard, the potential result if the hazard is ignored, and general
instructions about how to avoid the hazard.
The following labels are typically located on the accumulator.
DescriptionLabel
DANGER
Nitrogen gas under pressure. Improper testing
of precharge or disassembly without releasing
nitrogen gas can cause severe injury or death.
Release gas before disassembly.
Read instructions before testing or servicing.
WARNING
High pressure vessel.
Rapid discharging from disconnecting or
disassembly can result in personal injury or
death. See service manual for tools and
instruction for relieving pressure or charging.
Precharge only with dry nitrogen gas.
22 Series 111 Accumulator Product Information
4.0 Safety
DescriptionLabel
Skin injection hazard; release of fluid pressure.
High pressure fluid and penetrate skin.
Do not tamper with fittings or hoses.
Wear appropriate protection such as safety
goggles and gloves.
Maintain safe pressure levels.
Series 111 Accumulator Product Information 23
5.0 Installation
Topics:
•
About the Series 111 Accumulator Installation Procedure.....................................................................26
Series 111 Accumulator Product Information 25
5.0 Installation
5.1.0 About the Series 111 Accumulator Installation Procedure
There are two models of the Series 111 Accumulator.The following figure shows the typical mounting
configuration for the Models 111.11B and 111.12C Accumulators.
• The Model 111.11B Accumulator is mounted with a boss adapter fitting and O-ring seals.When the
accumulator is ordered as a component, the boss adapter and O-ring seals are not included with the
accumulator, they must be purchased separately.
• The Model 111.12C Accumulator is flush mounted with four bolts and O-ring seal(s).When the accumulator
is ordered as a component, the four bolts (grade-8) and O-ring seal(s) (maximum size 54.28 mm [2.137
in.] outside diameter, 47.22 mm [1.859 in.] inside diameter), are not included with the accumulator and
must be purchased separately.
Mounting Configurations
DescriptionItem
Model 111.11 BA
Boss Adapter Mounting O-rings1
Model 111.12CB
26 Series 111 Accumulator Product Information
DescriptionItem
Flange Mounting Bolt1
Flange Mounting O-rings2
Accumulator Mounting Bolts (4)3
5.1.1.0 Series 111 Accumulator Installation Procedure
Required equipment
The following equipment is required for accumulator installation:
• Open-end wrench and strap wrench (for the Model 111.11B)
• Hex key set and torque wrench (for the Model 111.12C)
Note:
When installing a replacement accumulator into an existing system, the replacement accumulator
should be precharged to the same pressure level as the accumulator being removed. Be sure that
this precharge level is recorded on the label of the replacement accumulator.
5.0 Installation
1. Mount the accumulator in the system after lubricating the mounting O-ring seal(s). Note the O-ring seal
configuration.
• For the Model 111.11B Accumulator Thread the unit onto the boss adapter fitting and securely tighten
it with a strap wrench.
• For the Model 111.12C Accumulator Lubricate and torque the four mounting bolts in increments
(according to the pattern shown in the “Mounting Configurations” figure) to a final torque of 108 N·m
(80 lbf-ft).
2. Check the accumulator precharge pressure as described in the related procedure.
Series 111 Accumulator Product Information 27
6.0 Maintenance
Topics:
•
Series 111 Accumulator Maintenance Guidelines..................................................................................30
•
Check the Accumulator Precharge........................................................................................................32
•
About Changing the Precharge Pressure..............................................................................................35
•
Purge Fluid from the Gas Chamber.......................................................................................................37
•
Remove the Accumulator......................................................................................................................38
Series 111 Accumulator Product Information 29
6.0 Maintenance
6.1.0 Series 111 Accumulator Maintenance Guidelines
Maintaining the proper pressure level for your accumulators is essential for optimum system performance
and component life. Review the following figure to familiarize yourself with the accumulator components and
their locations. Also review the following guidelines before performing any procedure.
Accumulator Components
DescriptionItem
Screws1
Accumulator valve assembly2
Accumulator valve protective cover3
Valve stem cap4
Locknut5
End cap6
Chamber7
Piston8
Hydraulic fluid end cap9
Hydraulic fluid port10
Locking pin11
Use the following guidelines to determine when maintenance is required.
• Check the precharge pressure at periodic intervals.The length of time between checks depends on how
the system is used. Some f actors to consider when estab lishing this time interval are operating frequency,
30 Series 111 Accumulator Product Information
6.0 Maintenance
displacement, and duration. Start with one month intervals until you determine that another interval is
more appropriate.
• Maintain a log book on the condition of the precharge at each check. Use this data to determine if the time
between checks should be increased or decreased and if maintenance is required.
• Because the precharge pressure level varies with a temperature change, the level should always be
checked at the same temperature. If it is not, use one of the following formulas to determine if the precharge
level is acceptable.
Degrees Celsius
DescriptionItem
Current pressure1
Original pressure2
273 + (current temperature)3
273 + (original temperature)4
Degrees Fahrenheit
DescriptionItem
Current pressure1
Original pressure2
460 + (current temperature)3
460 + (original temperature)4
• If a pressure line accumulator has a pressure level change of ±1.4 MPa (200 psi) between checks, the
accumulator requires maintenance or the time interval between checks needs to be shortened.
• If a return line accumulator has a change of ±50% of the original pressure level between checks, the
accumulator requires maintenance or the time interval between checks needs to be shortened.
• If the precharge pressure level increases at each check interval, this indicates that fluid is collecting on
the gas side (a small amount of fluid leakage is normal).When the precharge pressure level cannot be
Series 111 Accumulator Product Information 31
6.0 Maintenance
maintained within the limits, remove the fluid and charge the accumulator. If the levels are again e xceeded
at the first check interval, replace the piston seals after the initial fluid has been changed.
• If the precharge pressure level decreases at each check interval, this indicates gas leakage to the fluid
side.When the precharge pressure level cannot be maintained within the limits stated in the previous
guidelines, replace the accumulator piston seals.
• During normal operation, the accumulator piston should be near the center of the accumulator cylinder.
T o chec k the approximate piston location, note the w arm-to-hot transition point on the accumulator cylinder
wall during operation. If the piston is near the charging stem end, the accumulator may need charging. If
the piston is at the other end, the accumulator may have an excess charge, or more likely an excessive
amount of hydraulic fluid has collected in the gas chamber.
6.2.0 Check the Accumulator Precharge
The following equipment is required for any Series 111 Accumulator: Accumulator charging kit (MTS part
number 376986-01).
1.
Warning:
Accumulators are pressurized devices.
Pressurized accumulators and their parts can become lethal projectiles if disassembled
and can cause death to persons and/or damage to equipment.
Do not remove an accumulator that is pressurized. Completely remove hydraulic pressure
and discharge the accumulator before any parts, except the protective cover and valve stem
cap, are removed.
Ensure that system hydraulic pressure has been reduced to zero before proceeding.To do this, turn off
the hydraulic power unit and exercise the actuator until it stops moving.
2. Close the bleed valve on the accumulator charging kit. Remove the protective cover and valve stem cap
from the accumulator (see “Accumulator Components” and the figure below).
3. Check the precharge depending on the kind of accumulator on your system.
a) For an MTS Series 111 Accumulator, see "Check the Series 111 Accumulator Precharge".
b) For a non-MTS accumulator, see "Check a Non-MTS Accumulator Precharge".
32 Series 111 Accumulator Product Information
6.0 Maintenance
Accumulator Precharge
DescriptionItem
High Pressure Gage 0–21 MPa (0–3000 psi)1
Low Pressure Gage 0–2.1 MPa (0–300 psi)2
Gage Protector (factory set to limit pressure to the gage to approximately 1.4 MP a (200 psi)3
Extension Hose4
Check Valve:This valve will be either a poppet-type valve or a core-type valve.5
Locknut6
Valve Stem7
Poppet-Type Valve:To Open and Close Use Chuck Valve8
CloseC
OpenO
Valve Core9
Valve Stem10
Core-Type Valve:To Open and Close Use Chuck Valve11
OpenO
Series 111 Accumulator Product Information 33
6.0 Maintenance
DescriptionItem
CloseC
Customer supplied items12
Nitrogen Bottle Valve13
Nitrogen Bottle14
Nitrogen Bottle Pressure Gage15
Regulator Output Pressure Gage16
Regulator Output Pressure Valve17
Regulator Shut-Off Valve18
Nitrogen Supply Hose19
Input Check Valve20
Bleed Valve21
OpenO
CloseC
6.2.1.0 Check the Series 111 Accumulator Precharge
This procedure is a continuation of "Check the Accumulator Precharge." Steps 1-3 of that procedure should
be preformed before completing this procedure.
The Series 111 Accumulators use the poppet-type valve.
1. Connect the charging kit chuck valve to the accumulator valve stem.
2. With an open-end wrench, turn the locknut counterclockwise on the accumulator valve assembly to open
the valve. Read the pressure on either the high or low accumulator charging kit pressure gage.
• If the pressure reading is other than the required pressure level recorded on the accumulator, go to
the procedure “Change the Precharge Pressure.”
• If the pressure level corresponds to the level recorded on the accumulator label, turn the locknut
clockwise to close the valve and continue this procedure.
3. Open the bleed v alve on the accumulator charging kit and remove the chuck valve from the accumulator.
4. Replace the valve stem cap and protective cover on the accumulator.
6.2.2.0 Check a Non-MTS Accumulator Precharge
This procedure is a continuation of "Check the Accumulator Precharge." Steps 1-3 of that procedure should
be preformed before completing this procedure.
34 Series 111 Accumulator Product Information
6.0 Maintenance
Non-MTS accumulators typically use either a poppet–type valve or a core–type valve.
1. Determine which type of gas pressure valve is present on the accumulator and connect the charging kit
chuck valve to the accumulator valve stem.
2. Open the locknut (poppet-type) or chuck valve (core-type).
Note:
The poppet-type valve opens by turning the locknut counterclockwise and closes by turning the
locknut clockwise.To open a core–type valve, attach a chuck valve to the valve stem and turn the
chuck valve handle clockwise to depress the valve core. Close the valve by turning the handle
counterclockwise.
3. Read the pressure on either the high or low accumulator charging kit pressure gage.
The low pressure gage is limited to approximately 1.4 MPa (200 psi) by the gage protector.
• If the pressure reading is other than the required pressure level recorded on the accumulator, go to
the procedure “Change the Precharge Pressure.”
• If the pressure level corresponds to the level recorded on the accumulator label, close the locknut
(poppet-type) or close the chuck valve (core-type). Continue to Step 4.
4. Open the bleed v alve on the accumulator charging kit and remove the chuck valve from the accumulator.
5. Replace the valve stem cap and protective cover on the accumulator.
6.3.0 About Changing the Precharge Pressure
The precharge of an accumulator mounted on a hydraulic supply line often is increased to enhance system
performance and reduce the transient HPS flow demands. Accumulators ma y be precharged to 10 MPa (1500
psi) or more, although amounts above 14 MPa (2200 psi) will have less and less performance effect in most
situations. Be sure that you read the following warning before you charge your accumulator.
Warning:
Accumulators have specific pressure ratings.
If the precharge pressure is too high, the accum ulator can bottom out causing the release
of metal particles into the hydraulic fluid. Charging accumulators above their rated level
can damage system equipment.
Do not charge accumulators to pressures above their rated level. Charge accumulators below
their rated fatigue pressure of 21 MPa (3000 psi) for the Model 111.11B and 22 MPa (3200 psi)
for the Model 111.12C. Use a suitable regulator and gage set to an accumulator’s charges.
6.3.1.0 Decrease the Precharge Pressure
See “Check the Accumulator Precharge” to determine if you need to change the precharge pressure.
Series 111 Accumulator Product Information 35
6.0 Maintenance
1. Slowly open the bleed v alve on the accumulator charging kit until gas begins to escape .When the pressure
reading on the appropriate pressure gage drops to the level required, close the bleed valve.
2. Close the locknut (or close the chuck valve if you have a core-type valve). Open the bleed valve on the
accumulator charging kit and remove the chuck valve from the accumulator.
3. Install the valve stem cap and protective cover.
6.3.2.0 Increase the Precharge Pressure
See “Check the Accumulator Precharge” to determine if you need to change the precharge pressure.
1. Close the locknut on the accumulator (or close the chuck valve for a coretype valve).
2. Open the bleed valve two turns.
3.
Warning:
Mixing gases can produce unpredictable results.
Do not use another gas to precharge an accumulator.
Use only dry nitrogen gas to precharge accumulators.
Connect the nitrogen supply hose from the supply bottle pressure regulator output to the input check valv e
on the charging kit.
4. Open the nitrogen bottle valv e. Check the nitrogen bottle pressure gage on the regulator. (The bottle must
contain sufficient pressure to provide an adequate gas volume.)
5. Monitor the regulator output pressure gage and adjust the regulator output pressure valv e to the required
level.
6.
Caution:
Rapid flow rates with pressure differentials of more than 2.1 MPa (300 psi) across the
input check valve can damage the valve seal(s).
Avoid rapid and extreme pressure transitions.
Do not allow rapid flow rates. Open the regulator shut-off valve only far enough to permit a
gradual transfer of gas.
Slowly open the regulator shut-off valve until gas is heard escaping from the accumulator charging kit
bleed valve. Allow gas to slowly escape for approximately ten seconds, and then close the bleed valve.
Immediately close the regulator shut-off valve bef ore the pressure reading on either the high or low charging
kit pressure gage exceeds the pressure level of the accumulator.
7. Open the locknut (or open the chuc k valve for a core-type valve). Slowly open the regulator shut-off valve
until the pressure indicator on either the high or low charging kit pressure gage begins to rise.When the
pressure is at the required pressure level (recorded on the accumulator), close the regulator shut-off v alve.
8. Close the locknut (or close the chuck valve for a core type valve).
9. Open the bleed v alve on the accumulator charging kit and remove the chuck valve from the accumulator.
10. Install the valve stem cap and protective cover. Close the valve on the nitrogen bottle.
36 Series 111 Accumulator Product Information
6.0 Maintenance
6.4.0 Purge Fluid from the Gas Chamber
Piston-type accumulators may collect h ydraulic fluid in the gas chamber, which then reduces the gas volume
of the accumulator.The fluid should be purged from the gas side if a pressure check procedure shows one
or more of the following:
• A consistent trend of pressure being higher than expected.
• Precharging requires smaller volumes of gas than expected to obtain a desired pressure level.
• Fluid is expelled from a gas valve during gas venting.
Caution:
Venting pressurized gasses can generate loud noises and freezing temperatures.
Transferring gasses from high to low pressure containers creates freezing temperatures.
Do not work with pressurized gasses without wearing protective clothing.Wear heavy gloves,
safety glasses, and ear plugs when working with pressurized gases.
1. If the valv e stem of the accumulator is facing do wn, go directly to Step 2. If the valve stem of the accum ulator
is facing up or the accumulator is on its side, remove the accumulator as described in “Remove the
Accumulator” and turn it so that the valve stem is facing down.
2. Remove the accum ulator valve protectiv e cover and the v alve stem cap . Securely position the accumulator
with the gas valve down.
3. Place a suitable container under the valve stem to capture any expelled fluid. Use an open-end wrench
and open the locknut on the accumulator valve assembly two or three full turns. Allow gas pressure to
reduce to zero and any hydraulic fluid to be expelled.
4. Replace the accumulator as described in the Installation chapter.Then precharge the accumulator as
described in “Change the Precharge Pressure.”
Series 111 Accumulator Product Information 37
6.0 Maintenance
6.5.0 Remove the Accumulator
Warning:
Accumulators are pressurized devices.
Pressurized accumulators and their parts can become lethal projectiles if disassembled
and can cause death to persons and/or damage to equipment.
Do not remove an accumulator that is pressurized. Completely remove hydraulic pressure and
discharge the accumulator before any parts, except the protectiv e co ver and v alv e stem cap , are
removed.
1. Ensure system hydraulic pressure has been reduced to zero before proceeding.To do this, turn off the
HPS and turn on low pressure at the controller. Exercise the actuator until it stops moving.Then turn off
the electrical power.
2. Place a drain pan under the accumulator to be removed.
3. To prevent contamination of the hydraulic fluid, cover any ports that are exposed.
4. If you hav e the Model 111.12C Accumulator , use a hex k ey to remov e the flange and accumulator mounting
bolts (see “Actuator Components”). If you have the Model 111.11B Accumulator, use an open-end and
strap wrench to loosen the accumulator from the boss adapter fitting.
5. Perform any required maintenance (see the other procedures in this section).
6. To reinstall the accumulator, see “Series 111 Accumulator Installation Procedure”.
38 Series 111 Accumulator Product Information
011-553-304 D
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