TOBUL_TMBladder062309v1

8/10/2019 TOBUL_TMBladder062309v1

http://slidepdf.com/reader/full/tobultmbladder062309v1 1/4Phone: 803-245-5111 Fax: 803-245-2636 Tobul Accumulator, Inc. Bamberg, SC USA www.Tobul.com

Troubleshooting & Maintenance

Bladder-Type Hydraulic Accumulators

(Steel Shell W/Hemispherical Ends)

(TBR-Bottom Repairable Type)

WARNING: Accumulators, gas bottles and hydraulic systems are inherently

dangerous due to high pressure gases and fluids. DO NOT

ATTEMPT to maintain these systems unless adequately

trained, have experience with the items and systems in

question, and can recognize the potential risks involved if

mishandled. Always wear appropriate safety equipment.

READ & UNDERSTAND ALL INSTRUCTIONS PRIOR

TO SERVICING & MAINTAINING ACCUMULATOR!

GAS VALVE

GAS

CHAMBER

RUBBER

SEPARATOR

STEEL

BOTTLE

FLUID

CHAMBER

POPPET

ALVE

FLUID PORT

TROUBLE SHOOTING

The most prevalent concern with bladder

accumulators is the loss of pre-charge pressure.

Since accumulators function only due to the

differential pressure of the compressed gas

and the fluid utilized, any variation in the pre-

charge will result in operating difficulties or theloss of functionality. A loss of nitrogen gas pre-

charge may occur due to, but not limited to,

gas valve leakage or internal bladder damage/

failure. Some symptoms of these conditions

are: Failure of the bladder bag indicated by the

lack of functionality of the accumulator; Inability

to maintain pre-charge pressure or gurgling/

bubbling of the fluid reservoir – nitrogen gas is

leaking out of the bladder bag into system.

Insufficient pre-charge is a major concern

– a single cycle of hydraulic pressure into a

bladder accumulator without pre-charge can

result in significant damage to the bladder bag,

necessitating bladder replacement. Bladder

damage can also occur if the bladder is inflated

too fast with extremely cold nitrogen gas.

Nitrogen gas leakage from the gas valve

can occur if the valve is not tightened securely;

also, if dual wrenches are not used when

loosening a jam-nut style gas valve (Military

style or strut type) the lower body can break

free and allow the gas pressure to force the

o-ring seal out. If the valve body is simply re-

tightened, there is a distinct possibility thatthe o-ring will be cut and/or damaged by the

valve body, and the o-ring will not seal properly.

When loosening this type of valve, hold the base

of the valve securely with one wrench, while

loosening the upper jam nut with another.

Bladder accumulators function best when

mounted vertically. Horizontal orientation can

result in increased bladder bag wear due to

friction with the internal surface of the pressure

shell, along with any system contaminants

which collect in the shell. Horizontal mounting

also increases the possibility of fluid being

trapped away from the outlet valve.

For detailed procedures for checking and

adjusting pre-charge pressures, see Tobul’s

Operating and Maintenance Instructions.

V



Troubleshooting & Maintenance Bladder-Type Hydraulic Accumulators

Disassembly

NOTE: It is good practice to disassemble

and assemble accumulators in a cleanarea to keep all parts free of foreign matter.

1. Securely clamp the accumulator.

2. Follow instructions for checking pre-

charge, then release all pre-charge pressure.

3. Drain balance of hydraulic fluid that

may be remaining in accumulator

when it is disconnected from system.

4. Remove bladder stem lock nut and gas

valve from the top of the accumulator after

removing charging valve and gauge assembly.

5. Remove the bleeder plug and the lock

nut from the fluid port body at the

bottom of the accumulator using a spanner

wrench. Next remove metal spacer ring.

Note the lip of the spacer faces into the

shell opening to center the fluid port body.

6. Push the port and poppet valve body into

accumulator shell.

7. Insert hand into accumulator shell and

remove back up, o-ring and metal back-

up ring from fluid port body assembly.Remove anti-extrusion ring from body, then

fold in half and slide through shell opening.

Remove poppet valve/port body from shell.

8. Remove poppet valve/fluid

port body from the shell.

9. Insert hand into the

bottom of the

accumulator shell

opening. Compress

bladder by hand to

eliminate as much air

volume as possible.

10. Pull the old or damaged

bladder out of the bottom

of the accumulator shell. Examine the interior

of the shell for possible contaminants, pieces

of old bladder, etc. and clean/flush thoroughly




Re-Assembly

1. Lubricate the inside of the shell and the

outside of the bladder with clean systemfluid. Also pour additional amount of fluid

in the shell to act as a cushion. Remove gas

valve or valve core from new bladder. Attach

the bladder pull rod to the bladder bag.

2. Pull the rod and bladder through the shell

fluid port. Pull bladder stem out through

the valve stem opening on the opposite

end of the shell. Slide lock nut over pull

rod and thread on to bladder stem. Using

two wrenches, in order to prevent the

bladder bag from rotating inside the shell,

tighten lock nut. Remove the bladder pull rod.

3. Slide the fluid port body/poppet valve

assembly (poppet first) into the accumulatorshell. Fold the anti-extrusion ring in half and

slide it through the oil port opening. Place

the anti-extrusion ring on the port body/

poppet valve assembly with the stainless

steel ring facing toward the shell opening.

Pull plug through

accumulator shell

opening. Using both

hands, pull plug hard

until it seats into

position on shell

opening.

4. Install gas valve or valve core into bladder

stem. Using dry

nitrogen, SLOWLY

inflate the bladder

bag with 5-10 psig

of pressure to

set and hold fluid

port body/poppetassembly in place.

Install metal washer onto fluid port body/

poppet assembly. Push the metal washer

into shell opening until bottomed out.




5. Install o-ring over fluid port body/poppet

assembly and push into shell opening until

bottomed out. DO NOT ROLL OR TWIST

O-RING WHEN INSTALLING. Lubricateo-ring with system fluid or grease before

installation. Install plastic backup ring.

6. Install metal spacer with small shoulder

towards the accumulator shell. Note

the lip of the spacer faces into the shell

opening to center the fluid port body.

7. Install lock nut on plug and poppet assembly

and tighten securely with spanner wrench.

8. Replace bleeder plug in fluidport body/poppet assembly.

9. If unit is to be stored, introduce approximately

25 PSI of dry nitrogen gas into the bladder

bag to maintain bladder in optimum condition.

10. If unit is to be installed, proceed with

pre-charging, following all recommendations

in Tobul’s Operating and Maintenance

Instructions. Refer to ‘Pre-Charge Checking

and Adjustment Recommendations’ section.

Contact Tobul Customer Service/Sales

Engineering for assistance – 803-245-5111

Version 1.0 06.15.09

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TOBUL_TMBladder062309v1