Warnings & Safety

1. PROBLEM: STAR BURST (AT BOTTOM OF BLADDER)

Cause 1: Excessively rapid precharging causes bladder to freeze and burst, or extrude through plug orifice before poppet can close.

Solution: Always use an approved nitrogen gas regulator for precharging.

Cause 2: Low Fluid temperature causes bladder to become brittle.

Solution: Use a low temperature bladder.

Cause 3: Lack of lubrication on the bladder causes excessive stretching

Solution 3: Always lubricate bladder prior to use. Use fluids with good lubricity. Use a water service accumulator for water based or low lubricity fluids.

2. PROBLEM: STAR BURST (6” TO 8” FROM BOTTOM OF BLADDER)

Cause 1: Folding of bladder bottom during replacement causes it to be pinned against shell wall. Bladder cannot stretch to close the poppet and it bursts.

Solution 1: Never fold bladder when repairing unit.

3. PROBLEM: POPPET CUT (AT BOTTOM OF BLADDER)

Cause 1: Excessive flow rate causes bladder to extrude down through plug before poppet can close.

Solution: Use a High Flow Accumulator or multiple units of Standard Accumulators

Cause 2: Poppet does not close all the way, which causes the bladder to extrude.

Solution: Inspect plug and poppet assembly for damage, corrosion, or debris. Replace as needed.

Cause 3: Bottom of bladder has hardened due to the reduction of plasticizers from the elastomer, which is caused by excessive heat or chemical degradation.

Solution: Use a Viton or other bladder

4. PROBLEM: PICK-OUT (PIN HOLE NEAR TOP OF BLADDER)

Cause: Operation of the Accumulator with little or no precharge allows fluid pressure to force bladder to extrude into gas valve.

Solution: Always operate accumulator with proper nitrogen gas precharge. Check precharge often

5. PROBLEM: BUBBLES, BLISTERS OR RUBBER FLAKING ON BLADDER SURFACE OR BURNT SMELL

Cause: Incompatible fluid, or excessive temperature.

Solution: Refer to rubber compatibility chart and Temperature chart for correct elastomer compounds.

6. PROBLEM: TEARING OF BLADDER AROUND GAS VALVE STEM

Cause: Twisting of gas valve stem during replacement.

Solution: When tightening gas valve hex jam nut, use a second wrench to keep gas valve from twisting. Do not use excessive torque.

7. PROBLEM: GROOVES OR HOLES ON BLADDER SURFACE

Cause: Fluid contamination causes foreign debris entrapment between bladder and shell during cycling.

Solution: Use clean fluid and proper filtration.

8. PROBLEM: RUBBER HAS BECOME BRITTLE CAUSING CRACKS OR FLAKES

Cause: Excessive heat can cause the bladder to re-cure or harden due to the reduction of plasticizers from the elastomer.

Solution: Use a Viton or other bladder and/or install heat exchanger in system. Do not use or store units in hot environment or in direct sunlight.

9. PROBLEM: RUBBER IS BRITTLE IN COLD WEATHER SERVICE

Solution: Use a low temperature bladder.

10. PROBLEM: HAIRLINE CRACKS ON BLADDER SURFACE

Cause: Improper storage. Sunlight, fluorescent light, heat, dust and cold can cause bladder to weather check.

Solution: Store bladder in black bags provided with Accumulators, Inc. bladder kits. Store in 65-75 degree F. dark room.

11. PROBLEM: STRETCHING

Cause: Bottom of bladder has a small poppet mark indicating bladder has stretched due to adherence to wall from insufficient lubrication Solution: Use a fluid with more lubricity.

Solution: Use a water service accumulator with a coated interior.

12. PROBLEM: SET MARKS ON BLADDER CAUSED ADHERENCE TO SHELL WALL

Cause 1: After precharging, bladder was not cycled for an extended time period

Solution: Do not precharge bladder until just prior to service

Cause 2: Prior to precharging, bladder was not properly lubricated

Solution: Lubricate the bladder and shell prior to precharge The following causes account for 75% of all bladder warranty claims:

13. PROBLEM: SHARP CUT ON BLADDER SURFACE

Cause: Razor blade or knife used in customer’s receiving department.

Solution: Open bladder kits carefully!

14. PROBLEM: BROKEN VALVE CORE

Cause: Excessive torque used to install valve core.

Solution: Order replacement valve core.

15. PROBLEM: BROKEN OR DAMAGED GAS VALVE STEM OR THREADS

Cause: Excessive torque used to install gas charging valve (air chuck).

Solution: Hand tighten gas-charging valve during precharge.

16. PROBLEM: FLUID INSIDE OF BLADDER

Cause: There is a hole somewhere in the bladder.

Solution: Replace bladder.

17. PROBLEM: EXCESSIVE WEAR

Cause: Improper accumulator sizing.

Solution: Contact Accumulators, Inc. technical staff for recommendations.

18. PROBLEM: GAS VALVE STEM CORROSION

Solution: Order special service type bladders.

19. PROBLEM: GAS VALVE IS LEAKING GAS (Valve Stem Repair)

Cause: Dirt may get into the gas valve stem keeping the valve core from sealing.

Solution:

1. Turn off all system pressure, bleed fluid pressure from accumulator.
2. Bleed gas precharge pressure from accumulator
3. Remove valve core and throw it away
4. Using an approved valve core tool, clean the valve stem internal threads. (Do not use the tapered threads).
5. Remove the tool.
6. Using shop air or nitrogen, blow out the cleaned stem.
7. Replace the valve core with a new one.
8. Precharge using Dry nitrogen only. Follow instructions above.
9. Check for leakage using soapy water.
10. If leakage continues replace the gas valve stem.

The above list covers only the most common causes of non-warranty failure. Our in-house QC department, as well as our molders and chemists, have collected a wealth of experience in bladder analysis. There is often additional evidence and factors that can contribute to an evaluation. Most bladder failures are caused by a combination of factors, usually from the list above.

In general, bladder problems can be alleviated by proper sizing, correct compatibility and temperature evaluation, good hydraulic design, proper installation, appropriate precharging, good lubrication, and periodic maintenance. Accumulators Inc. does not warrant systems or fitness for purpose. A qualified fluid power specialist should review any application