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Principals / Partners

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“ Great things in business are never done by one
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Nakamura KokiPrincipals/Partners

70 years of Accumulators and Booster pumps....

"Product development ahead of the demands of the times." The fundamental philosophy of Nakamura Koki. 


nakamura accumulators n logo

Founded in 1953, 

Nakamura Koki Co., Ltd. started producing accumulators in 1963.

In 1965, the company entered into technical partnerships with GREER and OLAER PANTENT in the U.S.A. and acquired basic technologies related to global standard accumulators.

Since then the company has manufactured accumulators and has continuously offered a wide variety of unique products for half a century.

Although conditions in the industry are constantly changing, Nakamura Koki Co., Ltd. boasts unrivaled technologies and superior quality, and it has established itself as the market leader.



NAKAMURA KOKI appoints MOWE as their Exclusive Distributor in Singapore, Malaysia and Myanmar.

Mowe is also authorized to provide services including operations and maintenance of Nakamura products.



- Bladder & Piston Accumulators of various materials and pressure ratings.

- N2 Booster Pump skids / systems.

- Customised hydraulic Systems and Solutions for Offshore, Industrial etc.


Mowe Exclusive Distributor for Nakamura accumulators booster pump

Illustrates Accumulators, N2 Gas Booster Pump Skid , Accumulator Stand with Cylinders Accumulators.


Types of Accumulators Manufactured

Nakamura Bladder Type Miniorator Series M series Accumulator catalog

Miniorator series (M-Series) Accumulator

- The Mini-Orator series is the smallest capacity bladder type accumulator. As it can accommodate a wide range of materials for both the body (stainless steel, titanium alloy, etc.) and the bladder, it can also be used to absorb pulsation in pumps for special liquids.

Download Additional information:

file pdf download acrobat adobe reader 44516   -   Nakamura Bladder Type Miniorator Series (M-series) Accumulator Catalog


Nakamura Bladder Type General Series G series Accumulator

General Series (G Series) Accumulator

- The General Series is the world's most popular type of bladder accumulator. It is available in a range of capacities from small to medium, and is compatible with a wide range of body and bladder materials. It can be used for a wide range of purposes, including power compensation, pulsation absorption, and shock buffering.

Download Additional information:

file pdf download acrobat adobe reader 44516   -   Nakamura Bladder Type General Series (G-series) Accumulator Catalog


Nakamura Bladder Type TWIN OPEN Series T series Accumulator catalog

Twin Open Series (T-Series) Accumulator

- The Twin Open Series is a bladder-type accumulator that opens in both the upper and lower directions, and the bladder can be replaced from the upper opening without removing the accumulator body from the equipment. Our products range from medium capacity to some of the largest in the world, and can also be used for power compensation of large equipment.

Download Additional information:

file pdf download acrobat adobe reader 44516   -   Nakamura Bladder Type TWIN OPEN Series (T-series) Accumulator Catalog


Nakamura Bladder Damper series In Line Type D series Accumulator

In-line Type Accumulator (D-Series)

- In-line type accumulators are highly effective at absorbing pulsation because the fluid flows in direct contact with the bladder surface.

Download Additional information:

file pdf download acrobat adobe reader 44516   -   Nakamura Bladder Damper series In-Line Type (D-series) Accumulator Catalog


screen type P Type accumulator

Screen type accumulator (P-Type) Accumulator

- The screen type accumulator is a poppet-less type accumulator for low pressure (MAX. 3MPa). Since there is no poppet, there is no pinching at the bottom of the bladder due to the poppet closing, so it can be widely used for shock absorption and temperature compensation in water lines, petrochemical industry pipelines, etc.

Download Additional information:

file pdf download acrobat adobe reader 44516   -   Nakamura Piston Type Accumulator PA-Series Catalog


Transfer Barrier Type Accumulator B Type

Transfer Barrier Accumulator (B-Type)

- Transfer barrier accumulators are used to transmit pressure between different fluids, such as between oil and water, clean oil and dirty oil, etc. A tube with holes is inserted inside the bladder to prevent the fluid from hitting one point on the inner wall of the bladder directly and damaging the bladder.

Download Additional information:

file pdf download acrobat adobe reader 44516   -   Transfer Barrier Type Accumulator (B-Type) Catalog


Stainless steel accumulator S type Accumulator

Stainless Steel Accumulator (S-Type MGT-Series)

- In addition to being used for hydraulic equipment, accumulators are now often used for water and special fluids (such as high-purity cleaning water, chemicals, and sanitary fluids). This stainless steel accumulator is ideal for such purposes. Bladder-type accumulators made of titanium alloy or aluminum alloy are also available.

Download Additional information:

file pdf download acrobat adobe reader 44516   -   Stainless steel accumulator (S type) Accumulator Catalog


Hydro lung series BAB series Accumulator

Hydro-Lung Series (BAB-Series) Accumulators

- Hydro-lug is an air chamber air intake and exhaust device that is required when the amount of oil in the tank fluctuates, and is required in places where a sealed tank is required, such as in dusty environments or hydraulic systems for rotating objects. It can isolate the inside of the oil tank from the outside air.

Download Additional information:

file pdf download acrobat adobe reader 44516   -   Hydro-lung series (BAB series) Accumulator Catalog


Accumulators Accessories

  Nakamura Gasport Gas port assembly gas valve


Nakamura Coreless Gas Port Assembly Gas Valve Catalog

- The coreless gas port is a gas port equipped with a permanent pressure gauge and safety device. It is possible to check the gas pressure of the accumulator and adjust the pressure reduction without the need for a charging valve. Gas can be charged using only a charging hose.

Download Additional information:

file pdf download acrobat adobe reader 44516   -   Nakamura Coreless Gas Port Assembly Gas Valve Catalog


Nakamura Bladder Type Miniorator Series M series Accumulator catalog

Nakamura Charging Charge Assembly Catalog

- The charging valve is a special tool for charging nitrogen gas into our accumulators. (It cannot be used with accumulators from other companies.)

Download Additional information:

file pdf download acrobat adobe reader 44516   -   Nakamura Charging Valve Charge Assembly Catalog




- Shock Dampener (Water Hammer and Pressure Surge Absorder)

- Power Compensator

- Pump Pulsation Dampener

- Thermal Change Compensator

- Hydraulic Balancer

- Fluid Supplier

- Hydro-Pneumatic Shock Absorbers

- Transfer Barrier


- Well head control panels.

- Chemical injection skids / packages.

- Potable / Hot water packages.

- Emergency pump packages.

- Hydraulic power for energy storage.

- Cargo Systems, Subsea HPU and Winches & cranes.





Clients: SHELL, Petronas, Chiyoda, Toshiba, Tokyo, Mitsui, etc.

Nakamura Clients


Nakamura Bladder Care

Safety Precautions:

※※※Caution for safe use of accumulators※※※

An accumulator is a pressure vessel that uses high-pressure gas to store fluid pressure. Improper use or use/modification that exceeds the design standards is extremely dangerous. Be sure to observe the following points to prevent personal and material danger and to use the product safely.


1. Accumulator selection

The need to comply with national laws and regulations

Accumulators are pressure vessels that use high pressure gas, so they may be subject to laws such as the High Pressure Gas Safety Act and the Industrial Safety and Health Act (Class 2 Pressure Vessel) depending on the place of use, pressure used, capacity, etc.

Attention: Be careful when selecting an accumulator. If the product is intended for overseas use, please note that the laws of the country in which it will be used must be observed.

Please select and use the product suitable for the operating conditions (operating pressure, required oil volume, operating temperature, type of fluid, operating environment, applicable laws, etc.).

Please note that using an incorrectly selected product will not only result in a failure to achieve the expected performance, but may also have a negative effect on other equipment.


2. Installation of the accumulator

Never perform welding, screwing or drilling on the accumulator, as this may cause damage such as an explosion.

Secure the accumulator to the frame or wall with a band, etc. If the accumulator is only self-supporting, not only will excessive force be applied to each part due to vibration or earthquakes, but the screws may also become loose, creating a danger.

Do not expose the accumulator to external heat. If there is a heat source nearby or if it is exposed to direct sunlight, install a shielding plate. If the sealed gas inside becomes hot, an abnormal pressure rise will occur, which is dangerous.

In hydraulic piping systems that use accumulators, install a pressure control valve directly connected to the accumulator as a safety device to ensure that the maximum operating pressure of the accumulator is not exceeded.


3. Accumulator Charging guide / Nitrogen gas filling (Pre-Charge Pressure)

Always use nitrogen gas as the gas to be filled into the accumulator. Never use oxygen or flammable gases, as this may cause a fire or explosion and lead to disasters.

When a user fills an accumulator with nitrogen gas, the law does not apply, but the person in charge must receive training on handling high pressure gas and take care not to endanger third parties. Also, the charging assembly used to fill the gas must be compatible with the accumulator being used.

Dry nitrogen is used to precharge accumulators for several reasons:

(1) It is an inert gas. This means it will not react to external conditions such as heat and compression or pressurization. It also does not react readily with other chemicals.

(2) Although any inert gas could be used, nitrogen is the cheapest because it is the most readily available. 78% of the earth’s atmosphere is nitrogen, 21% oxygen, and 1% argon and other gases.

(3). Never use oxygen or compressed air to precharge an accumulator! As the oxygen is compressed it heats up and can cause a fire or explosion when mixed with the hydraulic oil.

Different manufacturers and styles of accumulator require different gauging/charging assemblies. Before beginning, be sure the style of accumulator and matches the charging assemblies and that they are intended to work together.

Accumulators and precharging kit

N2 Gas Charging Procedure

(1) Install the hose end of the gauging/charging assembly onto the nitrogen gas bottle.

(2) Verify the gas chuck is backed all the way out on the gauging assembly.

(3) Make sure the bleed valve is closed.

(4) Once steps #2 and #3 are verified, begin installing the gas chuck onto the gas valve.

(5) Turn the gas chuck in until pressure is indicated on the gauge. Do not turn the gas chuck all the way in, as this will damage the gas valve.

(6) Slowly crack open the nitrogen bottle valve; let the accumulator slowly fill until the gauge displays the desired precharge pressure.

(7) Shut off the valve on the nitrogen bottle.

(8) Let the precharge set for 10 to 15 minutes. If after this time, the precharge is too high, slowly open the bleed valve until desired pressure is reached. Then close the bleed valve.

(9) Do NOT reduce precharge pressure by depressing the gas valve core with a foreign object (such as a screwdriver) as this may damage the valve seat. Once the desired pressure is reached, screw the gas chuck out all the way.

(10) Open the bleed valve to relieve any pressure trapped in the assembly.

Accumulators should be precharged slowly, as indicated in step #6. This is especially important when filling a bladder style accumulator.

Below is a sequence of events outlining a common failure that will occur when a bladder style accumulator is charged too quickly:

• The nitrogen will travel quickly and hit the furthest end of the bladder, extending the bladder longitudinally to the full length of the shell.

• Meanwhile the rest of the bladder expands diametrically and fills out the rest of the shell.

• As the bottom of the bladder reaches the poppet valve, it goes around the poppet valve trying to extrude from the port intact and whole.

• By now, the rest of the bladder is also pushing down on the poppet valve which causes the portion of the bladder that is trying to extrude to get pinched.

• Once pinched, the nitrogen in the bladder escapes rapidly causing either a star burst or a 3/4 circle "C" cut on the bottom of the bladder.

Download Additional information:

file pdf download acrobat adobe reader 44516   -   Nakamura Charging Procedure for Accumulator


4. Handling the charging assembly

Remove the charging assembly from the accumulator except when using it for pre-pressure, pre-pressure correction, or pressure inspection.

If it is left permanently installed, it may cause gas leaks or damage to the attached pressure gauge.


5. Accumulator operation (use)

Please use the accumulator below the maximum operating pressure (design pressure). Applying excessive pressure may cause damage such as explosion.

If a bladder-type accumulator is left charged with gas for a long period of time (2 weeks or more) without applying hydraulic pressure, it may cause problems such as the bladder rubber sticking to the inside of the shell.


6. Accumulator maintenance

The gas charging pressure of the accumulator should be checked and adjusted immediately after preloading, after one week, and then every three months.

This is important to protect the bladder and maintain the functionality of the accumulator. When measuring the gas pressure, be sure to set the pressure in the hydraulic circuit to atmospheric pressure.


7. Disassembly, assembly and disposal of accumulators

Before disassembling the accumulator, make sure to return the pressure in the hydraulic circuit to atmospheric pressure, completely release the gas in the accumulator, and return it to atmospheric pressure. If pressure remains inside the accumulator, it may blow out during disassembly, which may cause injury.

When releasing nitrogen gas, ensure adequate ventilation. There is a risk of injury due to lack of oxygen. Also, check the direction the gas is being released from and make sure there are no people or objects moving lightly in that direction before releasing it. The force of the released gas is strong and there is a risk of injury.

Before reassembling the accumulator, check that each part is free of abnormal corrosion, scratches, deformation, etc. If a defective part is used as is, there is a risk of damage such as an explosion.

When reassembling the bladder of a Twin Open Series (T Series) bladder-type accumulator by removing the bladder from the top, be sure to drain the fluid that has accumulated at the bottom inside the shell. Accumulated fluid can cause abnormal deformation of the bladder due to buoyancy, which may result in the bladder being damaged.

When disposing of an accumulator, both the liquid and gas pressure should be returned to atmospheric pressure, and after disassembly, the accumulator should be disposed of appropriately as industrial waste after being treated so that it cannot be reused.

Additional information:

file pdf download acrobat adobe reader 44516   -   Nakamura Bladder Care & Safety Precautions for Accumulators



Download Additional information:

file pdf download acrobat adobe reader 44516   -   Nakamura Accumulators Brochure

file pdf download acrobat adobe reader 44516   -   Nakamura Piston Type Accumulator with Sensor LS-Series Catalog

file pdf download acrobat adobe reader 44516   -   Accumulators Selection Catalog

file pdf download acrobat adobe reader 44516   -   Bladder-Type Accumulators Drawing DWG30V-7119NB

file pdf download acrobat adobe reader 44516   -   Bladder-Type Accumulators Drawing DWG30V-11179NB

file pdf download acrobat adobe reader 44516   -   Calculation of Accumulator for Energy Storage - Mowe Sample 

file pdf download acrobat adobe reader 44516   -   G-Series and T-Series Accumulators Catalogue


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