FLOWSERVE LIMITORQUE PRODUCT SAFETY OVERVIEW

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FLOWSERVE LIMITORQUE PRODUCT SAFETY OVERVIEW
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• This presentation is designed to supplement
  Flowserve / Limitorques ongoing efforts to
  provide our customers with information designed
  to address the safe and proper use of valve
  actuators.

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Safety Precautions

• WARNING Read the Installation and Maintenance
  Manual carefully and completely before attempting
  to install, operate, or troubleshoot the
  Limitorque actuator.

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Maintaining Limitorque Actuators Safely
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Maintenance Preventive Maintenance

• Must be performed in accordance with the
  procedures outlined in the I/M manual
• Failure to do so may lead to premature failure of
  the actuator.

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Safety Practices

• Keep the valve stem clean and lubricated.
• Do Not over-tighten the packing gland.
• Set up a periodic operating schedule for
  infrequently used valves.

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Safety Precautions

• WARNING Do not manually operate the actuator
  with devices other than the installed handwheel
  and declutch lever.
• Use stem protectors
• Do not exceed rim pull (amount of force in lbs.
  exerted on hand-wheel needed to close valve)
• Do Not exceed 60 RPM for handwheel shaft input.
  Pneumatic or Hydraulic drives must be limited to
  60 RPM

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Event Description

• Previously, operators closed the Valve
  electrically
• Manual force was added with a 24 long valve
  wrench
• Upon start-up, operators attempted to open the
  Valve
• 6 attempts made to open electrically 4 followed
  by driving Valve in closed direction
• 3 attempts made to open manually

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Event Description (cont.)

• When the Valve came off the seat, boiler water
  pressure acting over the stem area generated a
  force (26,000 lbs of thrust) that was
  transmitted through the valve stem and into the
  housing
• The actuator failed, ejecting pieces of the
  housing which struck the employee

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Valve WrenchesFriend or Foe ??
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Mechanical Failure
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Mechanical Failure
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How Valves Work
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Bolted Bonnet Gate Valve
Bolted Bonnet Globe
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Forces to Operate a Valve

• Thrust
• Multi-Turn Valves
• Linear Force - Lbs to push disk thru the flow
• Push Pull Force created by applying torque to a
  threaded stem nut

• Torque
• All Valves
• Rotary Force - Ft-Lbs or Nm
• Torque is converted to Thrust through Acme
  Threads in Multi-Turn Valves

The bigger the valve and/or the higher the line
pressure/temperature, the higher the torque and
thrust!
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Actuator Principles of Operation
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SMB Electric Actuator
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Torque Limiter Plates

• Most Limitorque actuators are supplied with
  Torque Limiter Plate on the Torque Switch.
• Based on your application, this plate was
  selected to prevent possible damage to the valve
  or actuator.
• Removing, bending or otherwise altering this
  plate could have serious consequences.

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Handwheel Operation (SMB-0 to 5)
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How Do Actuators Operate a Valve
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How Do You Close a Gate Valve ?
Lets assume a 16 ANSI Class 600 Gate valve with
a 550 psi flow. We need to push the gate (wedge)
through the flow and into the seat. To push the
wedge, well use a 2 diameter stem with ¼ pitch
/ ½ lead Acme thread.

FLOW
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How Do You Close a Gate Valve ?
To generate the force (THRUST) required to push
the wedge through the flow and into the seat,
were going to use a Limitorque SMB-1 electric
actuator. The electric motor gear reduction
are selected to produce 750 ft/lbs of seating
torque the valve stem threads will convert the
torque to 35,000 lbs of thrust.
THRUST

FLOW
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SO ?

• How about explaining it in everyday terms ?

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• To produce 35,000 lbs of thrust,
• we would have to stack NINE Ford F-150s on top
  of the stem !

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Manual Operation

• The actuator handwheel is designed and sized to
  operate the valve in the event of power loss, NOT
  to provide more torque than is supplied
  electrically.

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Manual Operation

• Using the 12 diameter handwheel, we would have
  to put in 122 lbs on the rim of the HW to produce
  the 750 lbs of torque 35,000 lbs of thrust
  needed to close the valve through the flow.

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BUT

• If we use an 18 valve wrench on the 12
  handwheel and put the same 122 on it, we have
  quadrupled the moment arm and now have increased
  the torque and thrust to the valve by a factor of
  4!

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• NOW weve stacked the equivalent of
• 36
• Ford F-150s on top of that stem !

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• You just put over
• 140,000 lbs
• of force on that stem !
• This grossly overloads the valve the actuator,
  exceeding
• safe limits!!!

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A Little Perspective ..
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How Can We Create So Much Force?
Handwheel ratios (combination of handwheel gear
set and worm/worm gear set) vary from 8.941 to
59.131 (dependent on actuator size and motor
set/worm set ratio) Output Torque input torque
to handwheel shaft x handwheel ratio x eff. 122
on 12 HW (6 moment arm) is 62 ft.lbs. input
torque x 49.01 ratio x 25 eff. 759 ft/lbs.
output torque 122 on 18 valve wrench (24
moment arm)244 X 491 X .25 3038
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Torque to Thrust Conversion

• A threaded stem acts like a gear that converts
  rotary motion to linear motion and multiplies the
  force
• Torque / Stem Factor Thrust
• 759 / .021 36,142 Thrust
• 3038 / .021 144,666 Thrust

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• When closing the valve, all of the reactive
  forces are pushing up on the bearing housing
  cover of the actuator.
• In overload, it will crack under excessive loads!

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If the valve is leaking

• It probably is NOT an actuator problem.
• Check for possible
• Seat damage (steam cutting)
• Obstruction or trash
• Valve stem problem (lube, or packing)

Forcing the actuator beyond its torque or thrust
limit to seal a leaking valve is dangerous!
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MAXIMUM INPUT TORQUE

• Actuators and gearboxes have maximum torque input
  limitations.
• Exceeding these limits may result in
• Product Failure
• Personal Injury

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The use of

• Cheater bars
• Pipe wrenches
• Valve wrenches
• Spanner wrenches
• Or other devices to provide mechanical advantage
  is strictly prohibited.

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Safety Precautions
Warning The rim pull on an actuator is
determined by the load requirements the
gearing and many times is specified by the
customer. Actuators have been designed and
manufactured with a wide range of rim pull
requirements.
In order to determine the rim pull for an
existing actuator please provide the ORDER NO.
and SERIAL NO. to your Limitorque representative.
Limitorque can also supply rim pull plates that
will give the design and maximum rim pull.
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STOP !

• Use of the actuator must be stopped any time it
  fails to operate properly !

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CHECK

• Confirm power source and control circuitry
• Does it still fail to operate ?
• THEN
• Collect the Nameplate information and
• CALL (CK Valve Division)
• For authorized Flowserve/Limitorque Service

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contact

• Your local Limitorque Distributor
• Chalmers Kubeck 610-494-7030
• Or
• Rob Laird 610-960-4998

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Your Safety is important to us

• So lets review
• Read and follow the I/M manual for installation,
  operation and maintenance
• Use only genuine Limitorque parts and authorized
  Limitorque service technicians
• Dont rewire to bypass safety features
• Dont use valve wrenches, pipe wrenches or
  cheater bars to manually open or close a valve
• Keep electric, pneumatic, or hydraulic wrenches
  at less than 60 RPM input to the handwheel shaft.
• Dont remove or alter the Torque Limiter Plate

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Chalmers Kubeck can help

• Rimpull data plates
• Torque Limiting devices
• Stem covers and tubes to meet OSHA requirements
• Spring Compensation
• Safety surveys to assess condition of installed
  actuators
• Training courses available on our actuator lines
• Genuine Limitorque replacement parts
• Replacement actuators
• Authorized service technicians

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Rimpull Data Plate

• P/N 61-682-0969-1
• Contains original order number of actuator
• Has rim pull force required to operate valve by
  original design.
• Has maximum one-time rim pull force that the
  original actuator can withstand prior to failure.

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Handwheel Torque Limiting Device

• P/N OTC-2
• OTC-2 consists of over torque coupling, 18"
  fabricated steel handwheel, and input torque
  warning tag. The coupling is completely enclosed,
  bi-directional, non-friction type, and is factory
  set to trip at the max allowable torque for the
  specified actuator. Trip torque ranges from
  50-200 foot pounds. The coupling will
  automatically re-engage when the required torque
  drops below the trip torque.

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Torque Limiting Coupling (OTC-2)
Limits handwheel input torque, factory preset for
your application. Torque range between 50-200 lbs
of rim pull.
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• REVIEW
• Use handwheel torque limiting devices
• Use rim pull nameplates
• Use actuators where they were designed to be used
• Perform preventative maintenance
• Use Genuine Limitorque replacement parts
• Use stem covers or plugs
• Dont exceed the maximum input torque
• Stop any time an actuator fails to operate, get
  help
• Get training on actuator maintenance operation

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Thank You Be Safe!
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