Nakamura KokiPrincipals/Partners
ACCUMULATORS
& BOOSTER PUMP SYSTEMS
“Product development ahead of the demands of the times.”
Nakamura Koki Co., Ltd. combines decades of accumulator technology with hydraulic engineering solutions for offshore, industrial and specialised applications.
Nakamura Koki Co., Ltd.
Nakamura Koki Co., Ltd. was founded in 1953 and 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, Nakamura Koki has manufactured accumulators and continuously offered a wide variety of unique products for more than half a century.
Although conditions in the industry are constantly changing, Nakamura Koki Co., Ltd. has developed specialised technologies and product quality that have established the company as a market leader.
Exclusive Distributor
for Nakamura Koki
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.
Accumulator & Hydraulic Solutions
Bladder & Piston Accumulators
Various materials and pressure ratings for hydraulic, water and specialised fluid applications.
N2 Booster Pump Systems
Booster pump skids and systems for accumulator charging and nitrogen gas management.
Custom Hydraulic Systems
Customised hydraulic systems and solutions for offshore, industrial and specialised applications.
Types of Accumulators Manufactured
Miniorator Series Accumulator
The Mini-Orator series is the smallest capacity bladder type accumulator. It can accommodate a wide range of materials for both the body, including stainless steel and titanium alloy, and the bladder.
It can also be used to absorb pulsation in pumps for special liquids.
Download M-Series Catalog
General Series Accumulator
The General Series is described as the world's most popular type of bladder accumulator. It is available in small to medium capacities and supports a wide range of body and bladder materials.
Applications include power compensation, pulsation absorption and shock buffering.
Download G-Series Catalog
Twin Open Series Accumulator
A bladder-type accumulator that opens in both the upper and lower directions. The bladder can be replaced from the upper opening without removing the accumulator body from the equipment.
The range extends from medium capacity to some of the largest units in the world and can be used for power compensation of large equipment.
Download T-Series Catalog
In-Line Type Accumulator
In-line type accumulators are highly effective at absorbing pulsation because the fluid flows in direct contact with the bladder surface.
Download D-Series Catalog
Screen Type Accumulator
A poppet-less type accumulator for low pressure applications, with a maximum pressure stated as 3MPa in the source information.
It can be widely used for shock absorption and temperature compensation in water lines and petrochemical industry pipelines.
Download PA-Series Catalog
Transfer Barrier Accumulator
Used to transmit pressure between different fluids, such as oil and water or clean oil and dirty oil.
A perforated tube is inserted inside the bladder to help prevent direct fluid impact and bladder damage.
Download B-Type Catalog
Stainless Steel Accumulator
Designed for hydraulic equipment as well as water and special fluids such as high-purity cleaning water, chemicals and sanitary fluids.
Bladder-type accumulators made from titanium alloy or aluminium alloy are also available.
Download S-Type Catalog
Hydro-Lung Series
Hydro-Lung is an air chamber air intake and exhaust device required where the amount of oil in a tank fluctuates or where a sealed tank is required.
It can isolate the inside of the oil tank from outside air in dusty environments and hydraulic systems for rotating equipment.
Download BAB-Series Catalog
Accumulator Charging & Gas Accessories
Nakamura Coreless Gas Port Assembly Gas Valve
The coreless gas port is equipped with a permanent pressure gauge and safety device.
It allows accumulator gas pressure to be checked and pressure adjustment to be carried out without a charging valve. Gas can be charged using only a charging hose.
Download Gas Port Catalog
Nakamura Charging Valve / Charge Assembly
The charging valve is a special tool for charging nitrogen gas into Nakamura accumulators.
The charging assembly is specifically designed for Nakamura accumulators and cannot be used with accumulators from other companies.
Download Charging Assembly Catalog
What Can Accumulators Do?
Water hammer and pressure surge absorption.
Supports hydraulic power compensation.
Helps absorb pulsation generated by pumps.
Compensates for pressure changes caused by thermal variation.
Supports hydraulic pressure balancing functions.
Provides stored hydraulic fluid when required.
Provides shock absorption using hydraulic and gas energy.
Separates and transfers pressure between different fluids.
Where Nakamura Systems Are Applied
Selected Clients
Nakamura Koki products have been associated with customers including:
Nakamura Bladder Care
An accumulator is a pressure vessel that uses high-pressure gas to store fluid pressure. Improper use, modification or operation beyond design standards can be extremely dangerous.
Always follow the manufacturer's instructions and applicable laws, regulations and site safety requirements.
Accumulator Selection
Accumulators may be subject to national laws and regulations depending on the place of use, operating pressure, capacity and other conditions.
For overseas applications, comply with the laws of the country where the accumulator will be used.
Select the product according to operating pressure, required oil volume, operating temperature, fluid type, operating environment and applicable regulations.
Accumulator Installation
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 using a band or suitable support. Avoid relying on the accumulator as a self-supporting structure.
Protect the accumulator from external heat and direct sunlight. Install a shielding plate where necessary.
Hydraulic systems using accumulators should include appropriate pressure control/safety devices to ensure the maximum operating pressure is not exceeded.
Nitrogen Gas Charging
Always use nitrogen gas for accumulator pre-charging. Never use oxygen or flammable gases because of fire and explosion risks.
The person performing charging should be properly trained in high-pressure gas handling and use a charging assembly compatible with the accumulator.
Charging Assembly
Remove the charging assembly from the accumulator except when performing pre-pressure charging, correction or pressure inspection.
Leaving the charging assembly permanently installed may result in gas leakage or damage to the pressure gauge.
Accumulator Operation
Operate the accumulator below its maximum operating pressure / design pressure.
Leaving a bladder-type accumulator gas-charged for two weeks or more without applying hydraulic pressure may cause the bladder rubber to stick to the inside of the shell.
Maintenance
The source recommends checking and adjusting accumulator gas charging pressure immediately after preloading, after one week and then every three months.
When measuring gas pressure, set the hydraulic circuit pressure to atmospheric pressure.
Disassembly, Assembly & Disposal
Before disassembly, return the hydraulic circuit to atmospheric pressure and completely release the gas inside the accumulator.
When releasing nitrogen gas, provide adequate ventilation and ensure the discharge direction is clear of personnel and objects.
Before reassembly, inspect components for abnormal corrosion, scratches, deformation or other defects.
For Twin Open Series accumulators, drain any fluid accumulated inside the bottom of the shell before removing and reassembling the bladder.
For disposal, both liquid and gas pressure should be returned to atmospheric pressure. After disassembly, dispose of the accumulator appropriately as industrial waste after making it unsuitable for reuse.
N2 Gas Charging Procedure
Install the hose end of the gauging/charging assembly onto the nitrogen gas bottle.
Verify that the gas chuck is backed all the way out on the gauging assembly.
Make sure the bleed valve is closed.
Install the gas chuck onto the accumulator gas valve.
Turn the gas chuck until pressure is indicated on the gauge. Do not turn it fully in.
Slowly open the nitrogen bottle valve and fill the accumulator until the desired precharge pressure is reached.
Shut off the valve on the nitrogen bottle.
Allow the precharge to set for 10–15 minutes. Adjust pressure slowly through the bleed valve if required.
Do not reduce precharge pressure by depressing the gas valve core with a foreign object.
Open the bleed valve to relieve pressure trapped in the charging assembly.
Accumulators should be precharged slowly. The source explains that charging a bladder accumulator too quickly can result in bladder damage caused by rapid nitrogen expansion and pinching around the poppet valve.
Downloads & Catalogues
Nakamura Accumulator Technology