OPERATING AND MAINTENANCE INSTRUCTIONSON TOBUL ACCUMULATORS

INSTALLATION:

The accumulator in a hydraulic circuit should be place as near as practical to thesource of shock or potential energy need. Normally an accumulator should be installed in a vertical position with the oilconnection down. If space is not available, it may be installed horizontally; however,reduced life will be incurred. Piston type accumulators will have a decrease in pistonsteel life. The weight of the piston will press at the 6 oclock position increasing sealwear. By far the largest problem is contamination entering the accumulator and settlinginside the bore. Bladder types have an increase risk of the bladder bag floating, which traps usablefluid inside. The bladder can be pinched by the poppet valve closing, which ruptures thebladder. Horizontal position requires more care when draining the fluid from theaccumulator. When installing an accumulator using u bolt type clamps, care should beexercised so as not to distort the cylinder with excessive squeeze. Welding hangers tothe cylinder is not recommended. Mounting brackets are available from TOBUL. Thehydraulic fluid used must be kept free of foreign matter to prevent damaging the cylinderwall or the piston sealing rings. For maximum seal life, the fluid should be filtered to 10microns or less. It is not advisable to change the hydraulic fluid from that which theaccumulator was originally purchased without checking its compatibility with the sealmaterials.

PRECHARGING PROCEDURE

GENERAL INFORMATION:

The condition of the accumulator is primarily determined by periodic checking of theprecharge pressure. Hydraulic accumulators are pressure vessels and only qualifiedpersonnel should perform maintenance. Drain all fluid completely from accumulatorbefore performing any maintenance. DO NOT weld or braze directly on accumulatorshell. DO NOT use automotive type valve cores in high pressure accumulator gasvalves. The most accurate precharge readings can be taken when fluid pressure is at 0psig. Always observe the maximum working pressure and operating temperatureranges.

DO NOT USE OXYGEN FOR PRECHARGING ACCUMULATOR!

BLADDER ACCUMULATORS:

Remove valve protection guard and valve cap from accumulator. CAUTION! Be surevalve on high pressure nitrogen supply is securely closed. To charge the accumulator,use a charging hose and gauge assembly similar to TOBUL P/N GG2527F rated for3,000 psig (higher pressures available). Attach hose assembly to nitrogen supply andthe gas chuck to tank valve on gauge assembly. Attach gas cock on gauge assembly to

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(BLADDER ACCUM. CONTINUED)

gas valve on accumulator. TOBUL accumulators are equipped with several differenttypes of gas valves (some have a valve core, others do not). If the gas valve has adouble lock nut, loosen nut by turning counter-clockwise approximately 2 turns or untilnut touches gas cock fitting. SLOWLY open valve on nitrogen supply and allow the gasto flow in to accumulator. Once the desired gas precharge pressure has been reached,close valve on nitrogen supply, then turn lock nut on gas valve (if applicable) clockwiseuntil tight. Turn T-handle on gas cock counter-clockwise. Open drain cock to relievehose pressure; disconnect gauge assembly from accumulator. Replace gas valve capand protective guard.

NOTE: Allow accumulator to rest about 10-15 minutes after gas precharging. This willallow gas temperature to adjust and equalize. Recheck gas precharge pressure andadjust if necessary. Check accumulator gas valve for any leaks with soapy water.Always wear safety glasses.

PISTON ACCUMULATORS:

Consult the pressure volume curve to determine the optimum precharge setting. (It issuggested that this be 100 psig below minimum system operating pressure.) Theaccumulator size for any system should be of sufficient capacity to prevent the pistonfrom bottoming during operation. TOBULS accumulator sizing and selection softwarecan be used to determine the proper precharge pressure with appropriate temperaturecompensation. The accumulator gas valve has a guard over it which must be removedwhen the accumulator is to be charged or checked. Remove the (2) 3/8 socket headscrews with and an Allen wrench. CAUTION! Be sure valve on high pressure nitrogensupply is securely closed. To charge the accumulator, use a charging hose and gaugeassembly similar to TOBUL P/N GG2527F rated for 3,000 psig (higher pressuresavailable). Attach hose assembly to nitrogen supply and the gas chuck to tank valve ongauge assembly. Attach gas cock on gauge assembly to gas valve on accumulator.TOBUL accumulators are equipped with several types of gas valves (some have valvecore, some do not). If the gas valve has a double lock nut, loosen by turning counterclock wise approximately 2 turns or until nut touches gas cock fitting. Open by rotatingthe gas cock T-handle clockwise while holding the bottom fitting. SLOWLY open valveon nitrogen supply and allow the gas to flow in to accumulator, Once desired gasprecharge pressure has been reached, close valve on nitrogen supply, then turn locknut on gas valve (if applicable) clockwise until tight. Turn T-handle on gas cock counter-clockwise. Open drain cock to relieve hose pressure; disconnect gauge assembly fromaccumulator. Replace gas valve cap, guard, and 3/8 cap screws. Disconnect hoseassembly from nitrogen supply.

NOTE: Allow accumulator to rest about 10-15 minutes after gas precharging. This willallow the gas temperature to adjust and equalize. Recheck gas pressure and adjust ifnecessary. Check accumulator gas valve for any leaks with soapy water. Always wearsafety glasses.

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MAINTENANCE

CHECKING PRECHARGE PRESSURE

GENERAL INFORMATION:

The condition of the accumulator is primarily determined by periodic checking ofprechare pressure. Only qualified personnel should perform maintenance. Nitrogen gasprecharge pressure should be checked at least once during the first week of operation.The precharge pressure and ambient temperature should be recorded at installation. Ifthere is no loss of gas precharge pressure, it should be rechecked in approximately 4months. Thereafter, it should be checked annually.

BLADDER AND PISTON ACCUMULATORS:

The same procedure applies to both types of accumulators. Be sure pressure is 0psig on hydraulic end before checking precharge.

PISTON TYPE ONLY-Generally, an increase in pressure (after allowing for anyappreciable temperature variation) indicates a gradual leakage of fluid into the gas side.Conversely, a decrease in precharge pressure means leakage of gas into the fluid side.The amount of leakage will depend upon piston velocity. For very rapid cycling, checkthe precharge pressure monthly.

1. To check or adjust precharge pressure, HYDRAULIC PRESSURE MUST BEREDUCED TO 0 PSIG. Precharge pressure should be checked periodically atregular intervals following original installation. Charging and checking should bedone with an accumulator gauge assembly similar to TOBUL P/N GG2527F rated for3,000 psig (higher pressures available).

2. Remove gas guard as per precharging procedure instruction on either bladder orpiston type (whichever applies).

3. Attach gauge assembly to accumulator gas valve.

4. After making sure drain cock is closed, depress gas valve core by turning the T-handle on the gas cock clockwise. Gas Pressure can now be read on gauge.

5. To reduce pressure, open drain cock carefully, allowing gas to escape until desiredpressure is obtained.

NOTE: Allow accumulator to rest about 10-15 minutes after gas precharging. This willallow gas temperature to adjust and equalize. Recheck gas pressure and adjust ifnecessary. Check accumulator gas valve for any leaks with soapy water. Always wearsafety glasses.

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DISASSEMBLY

PISTON TYPE:

NOTE: It is good practice to disassemble and assemble accumulators in a clean area tokeep all parts free of foreign matter.

1. Follow instructions for checking precharge, then release all precharge pressure.

2. Drain balance of hydraulic fluid remaining in accumulator when it is disconnectedfrom system.

3. Remove gas valve.

4. Remove safety rupture valve from end cap if installed.

5. Remove end caps by turning cap counter-clockwise. On smaller units, there areeither flat surfaces for wrenching or two tapped holes for inserting screws so that a barcan be used.

6. To remove the piston, carefully tap with wooden dowel as it is guided out of thecylinder. Care should be taken not to damage piston or seals on threads of tube.

7. Examine seals on piston and end caps for sign of damage. Inspect closely for scoremarks or cuts. Excessive cuts on seals would warrant a very through examination ofmetal surfaces for damage.

8. Clean all metal parts with an approved cleaning solvent and dry with soft cleanmaterial.

9. Inspect cylinder bore for damage due to foreign material getting into the hydraulicsystem. All scratches must be removed from cylinder bore.

10. Inspect piston for damage due to bottoming.

REASSEMBLING

PISTON:

1. It is good practice to replace all seals when accumulator is completely disassembled.

2. Wet seals with system fluid and assemble into piston groove. Be sure seals are nottwisted.

3. Insert back-up rings carefully so as not to stretch any more than necessary.

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(Piston Type Continued)

4. Assemble piston carefully into cylinder to avoid cocking or damage to the piston orseal on the threads. If necessary, tap the piston lightly with a soft hammer. Special careshould be taken not to pinch the back-up rings.

5. Assemble back-up ring and o-ring into end cap groove. The back-up ring should betoward the threaded side or outside of the end cap.

6. Apply light grease to the threads and o-ring of the end cap and thread in to cylinderuntil end cap bottoms out.

7. Accumulator is now ready to receive precharge.

8. To precharge, follow Precharging Procedure instructions.

DISASSEMBLING

BLADDER TYPE:

NOTE: It is good practice to disassemble and assemble accumulators in a clean area tokeep all parts free of foreign matter.

1. Follow instructions for checking precharge, then release all precharge pressure.

2. Drain balance of hydraulic fluid that may be remaining in accumulator when it isdisconnected form system.

3. Securely clamp the accumulator.

4. Remove bladder stem lock nut, nameplate, and gas valve from the top of theaccumulator when it is disconnected from system.

5. Remove the lock nut from the bottom of the accumulator using a spanner wrench.Next remove spacer.

6. Push the plug and poppet assembly into accumulator shell.

7. Insert hand into accumulator shell and remove back up, o-ring and metal back-up ringfrom plug. Remove anti-extrusion from plug, then fold in half and slide through shellopening. Remove poppet plug assembly from shell.

8. Remove poppet plug assembly shell.

9. Insert hand into the bottom of the accumulator shell opening. Compress bladder by

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hand to eliminate as much air volume as possible.

10. Pull the old or damaged bladder out of the bottom of the accumulator shell.

REASSEMBLE

BLADDER TYPE:

1. Remove gas valve or valve core from new bladder.

2. Lubricate the inside of the shell and the outside of the bladder with clean system fluid.Also pour additional amount of fluid in the shell to act as a cushion.

3. Attach the bladder pull rod to the bladder system. Pull the rod and bladder throughthe shell fluid port. Pull bladder stem out through the valve stem opening on theopposite end of the shell.

4. Slid the nameplate and lock nut over pull rod and thread on to bladder stem. Tightenlock nut. Remove the bladder pull rod.

5. Slide the plug/poppet (poppet first) into the accumulator shell. Fold the anti-extrusionring in half and slide it through the oil port opening. Place the anti-extrusion ring on theplug and poppet assemble with its stainless steel ring facing toward the shell opening.

6. Pull plug through accumulator shell opening. Using both hands, pull plug hard until itseats into position on shell opening.

7. Install gas valve or valve core into bladder stem. Using dry nitrogen, SLOWLY inflatethe bladder bag with 5-10 psig of pressure to set and half plug and poppet assembly inplace.

8. Install metal washer onto plug and poppet assembly. Push into shell opening untilbottomed out.

9. Install o-ring over plug poppet assembly and push into shell opening until bottomedout. DO NOT ROLL OR TWIST O-RING WHEN INSTALLING. Lubricate o-ring withsystem fluid or grease before installation.

10. Install back up and spacer with small shoulder towards the accumulator shell.

11. Install lock nut on plug and poppet assembly and tighten securely with a spannerwrench.

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(Bladder Type Continued)

12. Replace bleeder plug in to plug and poppet assembly.

13. For precharging refer to Precharging Procedure for bladder type.

NOTES:

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TOBUL ACCUMULATOR, INC.186 ACCUMULATOR STREET

BAMBERG, SC 29003Telephone 803-245-5111

Fax 803-245-2636U.S.A.

O&M-720 7/95