The safe use of all our products is our goal. Please follow all warnings on, and attached to the unit, as well as safety instructions provided with the product and on our website.
- Bladders are shipped in sealed UV protective black bags. Store bladders in these bags until needed.
- The cartons in which the bladders were shipped are designed to prolong the storage life of the bladders. Keep the bladders in these boxes until the bladders are needed in service.
- Keep the tops of the cartons sealed at all times. After removing some of the bladders, reseal the carton. * By keeping the carton and bag closed, ozone attack from sunlight and artificial lighting may be minimized.
- Immediately upon receipt place bladders in a storage area. Keep this bladder storage area free from all sunlight, ultraviolet light, florescent lights, electrical motors, electronic equipment or other ozone producing items. At no time should the bladders be exposed to temperatures that exceed 80 F.
- Under the above conditions bladders may be stored for up to 6 months.
- Rotate your bladder inventory.
For longer-term storage, the following additional Optimum Conditions should be included:
- The storage area should be isolated in a closed clean room, maintained at 60 F to 72 F at all times.
- Bladders should be slightly inflated with dry nitrogen gas (N2) to 70% of their design diameter. Place in UV protective bags and hang vertically from the gas stem. If placed horizontally, they should be rotated monthly.
- Storage area must be dark, have no sunlight, ultraviolet light, florescent light or any heat source. Room should be dry, to prevent corrosion on the gas stem. No electrical motors, electronic equipment or other ozone producing items should be within 10 meters of the room.
- Under these conditions bladders can possibly be stored for up to 5 years.
Bladder “weather-checking”, often caused by improper storage, is not a covered warranty condition
Due to the nature of dynamic rubber products, bladders occasionally have ruptures or other problems. Please use this guide to help identify potential sources of bladder issues. If you still need help evaluating the problem, or believe your bladder has experienced a manufacturer defect, please contact us for further assistance.
Before installing, commissioning, or repairing your accumulator, please review our maintenance procedures ALWAYS remove ALL fluid and gas pressure from your accumulator before attempting any kind of service. Use dry nitrogen only. Selection, installation, and operation of any hydraulic product, including accumulators and accessories, should be supervised by a qualified fluid power specialist.
1. PROBLEM: Small hole in bladder near bladder stem, also known as “pickout”
Cause: This is the most common cause of bladder failure. Operation of the accumulator with insufficient precharge allows fluid pressure to force the bladder to extrude into the gas valve, which then creates a small hole in the bladder.
Step 1: Consult with a qualified fluid power specialist to determine the proper accumulator precharge for your application. You can use our precharge calculator as a guideline. It is important to check the precharge frequently as nitrogen gas permeates rubber bladders and seals over time.
Step 2: You will need to discard any bladder that has a pickout
2. PROBLEM: The bladder tore in the side wall during installation
Cause: This problem is caused by insufficient lubrication prior to precharge. As the bladder expands it can stick to the inside wall of the accumulator unless there is proper lubrication; the bladder then continues expanding past its elasticity limit and tears.
Step 1: Ensure that you are following official installation procedures. Thoroughly lubricate outside of bladder and inside of accumulator shell using your system’s fluid before installation and/or use. Using an accumulator with special coatings on the ID may be necessary for use with water-based and other low-lubricity fluids.
Step 2: Slowly charge your accumulator to 35 psig and then continue to charge the bladder to desired system pressure. You should only charge the accumulator with dry nitrogen using an approved nitrogen gas regulator.
Step 3: You will need to discard any bladder that is torn.
3. PROBLEM: The bladder tore in the side wall during operation
Cause: This problem is caused by insufficient lubrication during operation. As the bladder expands it can stick to the inside wall of the accumulator unless there is proper lubrication; the bladder then continues expanding past its elasticity limit and tears. Often, an accumulator has proper lubrication when installed and precharged, but loses that lubrication over time, especially when the accumulator is inactive for longer periods or is installed in a warm environment.
Step 1: Ensure that you are following official installation procedures. Thoroughly lubricate outside of bladder and inside of accumulator shell using your system’s fluid before installation and/or use. Using an accumulator with special coatings on the ID may be necessary for use with water-based and other low-lubricity fluids.
Step 2: Slowly charge your accumulator to 35 psig and then continue to charge the bladder to desired system pressure. You should only charge the accumulator with dry nitrogen using an approved nitrogen gas regulator.
Step 3: Bladder accumulators should be checked periodically for proper lubrication. If in doubt, go ahead and add more system fluid on the outside of your bladder and the inside of your accumulator shell – more lubrication is typically better. Be sure to remove all fluid and gas pressure from your accumulator before attempting any kind of service.
Step 4: You will need to discard any bladder that is torn.
4. PROBLEM: Star burst pattern at bottom of bladder
Cause: When you add nitrogen to the accumulator, If the charging rate is too high, the bladder may expand too quickly and extrude through the fluid port orifice before the poppet valve can close. Additionally, rapidly expanding gasses can drop in temperature very quickly, which may freeze or embrittle sections of the bladder, causing a burst or increasing the likelihood of extrusion. This can also be caused by system temperatures that are too low for the accumulator.
Step 1: Check your system temperature to ensure it is within the temperature range for the bladder you are using. You may need to use a special low-temperature bladder.
Step 2: Ensure that you are following official installation procedures. Thoroughly lubricate outside of bladder and inside of accumulator shell using your system’s fluid before installation and/or use. Using an accumulator with special coatings on the ID may be necessary for use with water-based and other low-lubricity fluids.
Step 3: Slowly charge your accumulator to 35 psig and then continue to charge the bladder to desired system pressure. You should only charge the accumulator with dry nitrogen using an approved nitrogen gas regulator.
Step 4: You will need to discard any bladder that has a star burst pattern.
5. PROBLEM: Star burst pattern on side wall of bladder, typically 6-8” above the bottom of the bladder.
Cause: Sometimes the bladder doesn’t uncurl properly when being installed for the first time. This can cause the bottom of the bladder to get stuck to the side wall of the shell and then the side of the bladder tries to extrude through the fluid port during precharge or operation.
Step 1: Check your system temperature to ensure it is within the temperature range for the bladder you are using. You may need to use a special low-temperature bladder.
Step 2: Ensure the bladder is completely uncurled/unfolded before installation and that it does not have any significant creases due to improper storage.
Step 3: Ensure that you are following official installation procedures. Thoroughly lubricate outside of bladder and inside of accumulator shell using your system’s fluid before installation and/or use. Using an accumulator with special coatings on the ID may be necessary for use with water-based and other low-lubricity fluids.
Step 4: Slowly charge your accumulator to 35 psig and then continue to charge the bladder to desired system pressure. You should only charge the accumulator with dry nitrogen using an approved nitrogen gas regulator.
Step 5: You will need to discard any bladder that has a star burst pattern.
6. PROBLEM: Poppet cut at bottom of bladder or side of bladder
Cause: The bladder can be cut by the poppet when the bladder expands into the fluid port orifice before the poppet valve closes. This typically occurs when the bladder is charged too quickly, when the in-use flow rate of the system is too high, when there is something blocking the poppet valve from closing properly, or when the bladder expands off-center due to insufficient lubrication prior to precharge.
Step 1: Ensure that you are following official installation procedures. Start by slowly charging your accumulator to 35 psig and then continue to charge the bladder to desired system pressure. You should only charge the accumulator with dry nitrogen using an approved nitrogen gas regulator.
Step 2: Inspect the fluid port assembly for damage, corrosion, or debris. Pay special attention to the center bore hole that allows the poppet valve to open and close.
Step 3: Check the flow rate of the accumulator while in use in your system. Our standard accumulators can handle up to 200 gpm and our high-flow accumulators can handle up to 600 gpm. Special-order accumulators will be necessary above 600 gpm, or you can use multiple accumulators.
Step 4: Thoroughly lubricate the inside of the accumulator shell and the outside of the bladder using your system’s fluid before installation and/or use. Using an accumulator with special coatings on the ID may be necessary for use with water-based and other low-lubricity fluids.
Step 5: You will need to discard any bladder that has a poppet cut.
7. PROBLEM: Bubbles or blisters on the bladder
Cause: Small bubbles in the bladder typically occur when a little bit of air gets mixed into the rubber during the bladder molding process. Small bubbles that were not initially present can become enlarged as the rubber stretches and compresses many times over the life cycle of the product. Additionally, gas can permeate the rubber over time, typically due to long-term pressurization.
Step 1: Determine whether the bubbles are a problem. Some bubbles are to be expected, especially after a bladder has been in service for a while. If the bubbles in your bladder meet any of these criteria, please contact us for further discussion:
- The bubble size exceeds ½” in length
- The bubble crosses a bladder seam
- The bubble is located at the very bottom of the bladder, where it makes contact with the poppet valve
- There are more than five bubbles between ¼” and ½” on the bladder
- The bubbles look like a “rash” on the bladder
Step 2: If none of the above criteria are met, your bladder can continue to be used in operation as long as it holds pressure. If you have further concerns, please contact us.
8. PROBLEM: The bladder looks like it has a “rash” on it or has many small stretch marks
Cause: This problem is caused by chemical incompatibility, excessive temperature, or too much exposure to UV light.
Step 1: Use our Rubber Compatibility Tool to check that you are using the proper elastomer for your system fluid.
Step 2: Check the recommended temperature range for your elastomer. Make sure to check both system temperature and storage conditions to ensure they are within the bladder’s temperature threshold.
Step 3: Ensure your spare bladders are kept sealed in Acc Inc’s original UV-proof black bags until installation.
Step 4: Contact us to determine whether the bladder can continue to be used in operation.
9. PROBLEM: Burnt smell
Cause: This problem is caused by chemical incompatibility or excessive system temperature.
Step 1: Use our Rubber Compatibility Tool to check that you are using the proper elastomer for your system fluid
Step 2: Check the recommended temperature range for your elastomer.
Step 3: Contact us to determine whether the bladder can continue to be used in operation.
10. PROBLEM: Tearing of bladder around bladder stem
Cause: If too much torque is used when installing a gas valve into the bladder stem or if the valve stem is not secured with a second wrench, the rubber can twist and possibly tear.
Step 1: When installing a gas valve into the bladder stem, you should use a second wrench to hold the bladder valve stem stationary. Doing so will keep the stem from twisting. Please see our item AI-515-KIT.
Step 2: Discard any bladder that has a tear in it.
11. PROBLEM: Small grooves, pits, or scoring on bladder surface
Cause: Fluid contamination can cause foreign debris to become trapped between the bladder and the shell during operation.
Step 1: Make sure your system fluid is clean and has proper filtration
Step 2: Contact us to determine whether the bladder can continue to be used in operation.
12. PROBLEM: Bladder rubber has become brittle; appearance of cracks or flakes
Cause: Excessive heat or chemical incompatibility can leach out the plasticizers from the rubber, and may cause the bladder to re-cure, harden, or lose structural integrity.
Step 1: Use our Rubber Compatibility Tool to check that you are using the proper elastomer for your system fluid
Step 2: Check the recommended temperature range for your elastomer. Make sure to check both system temperature and storage conditions to ensure they are within the bladder’s temperature threshold.</span
Step 3: Contact us to determine whether the bladder can continue to be used in operation.
13. PROBLEM: Sharp cut on bladder surface
Cause: Rubber products can easily be damaged by tools used during receiving. A razor blade or knife used to open the box can easily slice a bladder.
Step 1: Verify your receiving procedures to ensure future bladders are not damaged during unboxing.
Step 2: Discard any bladder that has a slice in it.
14. PROBLEM: Damaged valve core
Cause: Valve cores typically break when excessive torque is used during valve core installation.
Step 1: Ensure all fluid and gas pressure has been removed from your accumulator.
Step 2: Use a valve core removal tool, our part number AI-506, to remove the damaged valve core.
Step 3: Order a replacement valve core, part number AI-S-304 . Many valve cores look the same, so make sure you are using AI-S-304 in Acc Inc gas valves.
Step 4: Ensure you are using an Accumulators, Inc. torque wrench, part number AI-527, for installation of the replacement valve core.
Step 5: Lubricate and install the replacement valve core.
15. PROBLEM: Damaged/broken gas valve
Cause: Bladder gas valves typically break when excessive torque is used during gas valve installation. The threads can also be damaged by the installation tools.
Step 1: Ensure all fluid and gas pressure has been removed from your accumulator.
Step 2: Remove the damaged gas valve.
Step 3: Order a replacement gas valve.
Step 4: Install the replacement gas valve using the proper tools.
16. PROBLEM: Corroded valve core or gas valve.
Cause: While our valve cores and gas valves are made from corrosion-resistant materials, no product is foolproof for every environment. Corrosion is sure to happen eventually, especially in harsh environments such as found in many offshore and chemical applications.
Step 1: Valve cores and gas valves are typically pretty easy and inexpensive to repair. Order the correct replacement parts.
Step 2: Ensure all fluid and gas pressure has been removed from your accumulator.
Step 3: Remove the damaged components.
Step 4: Install the replacement components using the proper tools.
17. PROBLEM: Fluid inside the bladder
Cause 1: Fluid can get into the bladder if there is a hole/tear/cut somewhere in the bladder.
Cause 2: If you are using a transfer barrier accumulator, the fluid inside the bladder may be intentional as part of your application.
Step 1: Determine if there is a hole/tear/cut in the bladder by charging to 35 psi and leaving for at least 12 hours in an environment with a stable temperature.
Step 2: If the bladder holds pressure, drain the fluid by turning the bladder upside down and allowing it to drip out. You may then reinstall the bladder.
Step 3: If the bladder did not hold pressure, discard it and replace with a new one.
18. PROBLEM: Gas valve is leaking nitrogen
Cause 1: Dirt may get into the gas valve stem keeping the valve core from closing and sealing properly.
Cause 2: Corrosion or damage to the gas valve, valve core, or gas valve seals. If you suspect this cause, please see the instructions elsewhere on this page for evaluating damaged valve cores and gas valves.
Step 1: Ensure all fluid and gas pressure has been removed from your accumulator.
Step 2: Remove valve core and throw it away. Use a valve core removal tool, our part number AI-506, to remove a damaged valve core.
Step 3: Clean the threads in both the bladder valve stem and the gas valve with a soft brush.
Step 4: Using shop air or nitrogen, blow out the cleaned components to remove any debris.
Step 5: Replace the valve core, part number AI-S-304.
Step 6: Precharge the accumulator using dry nitrogen; keep it isolated from your system.
Step 7: Check for leakage using soapy water. Then monitor accumulator pressure for several hours to ensure it is holding pressure.
Step 8: If the bladder is still not holding pressure, replace the gas valve and repeat steps 6-7.
Step 9: If the bladder is still not holding pressure, Contact us for further assistance.
The above list covers only the most common causes of bladder problems. Our in-house engineering department, as well as our molders and lab chemists, have collected a wealth of experience in bladder analysis. There is often additional evidence and factors that can contribute to an evaluation. Some bladder failures may be caused by a combination of factors.
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.
You should only use dry nitrogen gas (N2) to precharge your hydraulic accumulator. Always use genuine Accumulators, Inc. replacement parts and accessories to repair our accumulators. Accumulators, Inc. fully warrants all accumulators, parts, and accessories to be free of any material or assembly defects. See our product warranty for details.
Caution: Operation of a hydraulic accumulator without sufficient precharge can damage the accumulator and cause it to fail. Please contact us or use our Accumulators Sizing Calculator for help determining the proper precharge for your application.