The power plant’s Electrohydraulic Control (EHC) system plays a crucial role in the reliable operation of a power generation plant, and its efficiency depends on several key factors, including oil cleanliness and Total Acid Number (TAN). The EHC system utilizes EHC fluids like hydraulic oil, often a phosphate ester fluid, to precisely control and move critical components such as turbines, steam turbines, valves, and actuators.

The cleanliness of the oil is of utmost importance 

Acting as a lubricant and coolant within the EHC system, any contaminants present in the oil, such as dirt, debris, or particles, can lead to abrasion, wear, and damage to both internal and external components of the hydraulic power unit. Such issues may result in increased friction, reduced efficiency, and, in severe cases, catastrophic failures. To prevent these complications, it is essential to conduct regular oil analysis and filtration to maintain the required cleanliness level. This proactive approach ensures smooth operation and extends the overall lifespan of the EHC system.

The Total Acid Number (TAN) of the oil is a critical parameter to monitor. 

Hydraulic systems that contain acidic oil are prone to corrosion of metal surfaces and degradation of seals and gaskets. The presence of water and acids further accelerates the oil’s deterioration, compromising its lubricating properties and overall performance within the EHC system.

Regular monitoring of the TAN number 

Monitoring through oil analysis allows for early detection of acid buildup, enabling timely maintenance actions like oil replacement or chemical treatment to neutralize acidity. By controlling the TAN within specified limits, the EHC system operates reliably, minimizing downtime, and mitigating the risk of costly repairs or unplanned shutdowns.

Use Fire Resistant Fluids

To address these challenges effectively, utilizing fire-resistant fluids, such as phosphate ester fluids, is highly recommended. These fluids not only offer improved fire safety in the power plant environment but also exhibit better resistance to degradation, reducing the risk of acidity formation (thereby, fluid degradation) and enhancing the longevity of the EHC system.

PIon Exchange Technology

Additionally, implementing ion exchange technology for water removal in hydraulic oil can significantly contribute to maintaining oil purity. Both old and new EHC systems can benefit from off-line oil filtration and water removal systems, which play a crucial role in ensuring the optimal performance of the EHC system.

In conclusion, the power plant’s electrohydraulic (EHC) system relies on various factors to operate reliably and efficiently. By focusing on oil cleanliness, controlling acidity levels with regular TAN monitoring, and utilizing fire-resistant fluids like phosphate ester fluids, the power plant can enhance the performance and safety of the EHC system. Additionally, incorporating ion exchange technology and off-line oil filtration further contributes to maintaining the purity of the hydraulic oil, ensuring uninterrupted operation and reinforcing the overall reliability and safety of the power generation plant.


For assistance in maintaining oil purity and optimizing EHC system performance, do not hesitate to contact us. Our expert team is ready to provide the necessary support and solutions to meet your specific needs.


In the realm of hydraulic systems, engineers often rely on the likes of a hydraulic accumulator and nitrogen to address various challenges such as energy storage, pressure regulation, and shock absorption.

Nitrogen, a prominent element constituting approximately 78% of the Earth’s atmosphere, plays a vital role in hydraulic systems, particularly in hydraulic accumulators. These devices serve critical functions such as energy storage, pressure regulation, and system stability.

We’ll delve into the reasons behind the extensive utilization of nitrogen in hydraulic accumulators, considering its impact on performance, safety, and broader environmental considerations.

We will also explore related key phrases such as carbon dioxide, boiling point, ammonia (NH3), piston accumulators, liquid nitrogen, atmospheric nitrogen, nitrogen compounds, and diaphragm accumulators.


Energy Storage and Pressure Regulation:

One of the primary reasons nitrogen is used in hydraulic accumulators is its ability to store energy effectively. These devices store pressurized hydraulic fluid, and by compressing nitrogen gas, potential energy can be stored for later use.

Nitrogen’s high boiling point, which allows it to remain in a gaseous state under normal operating conditions, and its ability to withstand high pressure make it suitable for this purpose. When hydraulic power demand arises, the pressurized fluid is released, converting the stored potential energy into kinetic energy, thereby driving actuators or performing work.


Safety and Stability:

In addition to energy storage, the utilization of nitrogen in hydraulic accumulators helps regulate pressure and maintain system stability. By serving as a cushion, nitrogen absorbs pressure fluctuations caused by variations in hydraulic pump flow or sudden changes in fluid demand.

This pressure regulation function helps stabilize the hydraulic system, safeguarding it against excessive pressure surges that could damage components or compromise safety. Additionally, nitrogen’s inert and non-reactive nature minimizes the risk of combustion or reaction with hydraulic fluid, further enhancing overall safety.


Nitrogen Compounds and Nitrogen Cycle:

While nitrogen gas (N2) is the most abundant element in the Earth’s atmosphere, it primarily exists as a diatomic molecule. However, nitrogen can be transformed into various nitrogen compounds, such as ammonia (NH3), through processes like the nitrogen cycle.

Although nitrogen compounds are not directly involved in hydraulic accumulators, understanding their role in natural systems highlights the versatility and significance of nitrogen in different contexts. The nitrogen cycle, which involves the conversion of atmospheric nitrogen into forms usable by living organisms, showcases the essential role nitrogen plays in sustaining life on Earth.


Environmental Considerations:

Considering the growing focus on environmental sustainability, the use of nitrogen in hydraulic accumulators raises important considerations. While nitrogen gas itself is not a greenhouse gas, its production process can contribute to carbon dioxide emissions. Industrial processes like fractional distillation of air are commonly employed to extract nitrogen from the atmosphere.

Consequently, manufacturers and engineers must strive to minimize the environmental impact associated with the production and utilization of nitrogen gas in hydraulic systems. Embracing energy-efficient manufacturing practices, exploring alternative nitrogen extraction methods, and optimizing hydraulic system designs can help mitigate the environmental footprint.


Types of Accumulators – Piston, Bladder and Diaphragm:

In hydraulic systems, three common types of accumulators are piston accumulators, bladder accumulators, and diaphragm accumulators. These devices utilize nitrogen gas for energy storage and pressure regulation. In piston accumulators, nitrogen is compressed behind a piston, while in bladder accumulators & diaphragm accumulators, a flexible bladder or diaphragm separates the nitrogen and hydraulic fluid.

All designs leverage nitrogen’s compressibility and inert nature to perform their respective functions efficiently. Engineers carefully select the appropriate accumulator type based on the specific requirements of the hydraulic circuit and system design.

Nitrogen, an abundant element in the atmosphere and a key component of hydraulic accumulators, plays a crucial role in enhancing performance, safety, and considering environmental sustainability in hydraulic systems Its properties, such as energy storage, pressure regulation, stability, and inertness, make it a preferred choice for maintaining system efficiency. By harnessing the unique characteristics of nitrogen, engineers can optimize the functionality, reliability, and safety of hydraulic systems, ensuring smooth operations in various industrial and mechanical applications.

As technology continues to advance, researchers and engineers are continuously exploring innovative methods and materials to further improve hydraulic system performance and minimize environmental impact. While nitrogen remains a prevalent and reliable choice for hydraulic accumulators, ongoing research is being conducted to explore alternative gases, materials, and designs that can further enhance the efficiency, safety, and sustainability of hydraulic systems.

In conclusion, nitrogen’s abundance, properties, and inert nature make it a valuable component in hydraulic accumulators. Its role in energy storage, pressure regulation, system stability, and environmental considerations showcases its significance in the field of hydraulics. By incorporating nitrogen into hydraulic system designs and adopting sustainable practices, engineers can achieve optimal performance, safety, and environmental responsibility, paving the way for a more efficient and sustainable future in hydraulic applications.

Electro-hydraulic systems combine the benefits of electrical signal processing with hydraulic drives to create versatile and reliable control systems. These systems can be categorized into three groups based on functionality, each offering unique advantages and applications.

1. Solenoids

The first group of electro-hydraulic systems uses solenoids to open or close hydraulic valves. The signal processing is performed using relay technology, making it suitable for applications with sufficient simple on/off control. These systems are typically used in agriculture, construction, and transportation industries.

2. Proportional Valves

The second group of electro-hydraulic systems uses proportional valves that allow for continuous adjustment to changing setpoints, resulting in better compensation for the progression of processes. The setpoints can be retrieved via machine controls or a programmable logic controller (PLC), and the signal processing is performed electronically. These systems are ideal for applications that require precise control and adjustments, such as in the chemical, food processing, and pharmaceutical industries.

3. Servo Valves

The third and final group of electro-hydraulic systems uses high-response proportional valves or servo valves. These systems use continuous sensors and electronic control amplifiers to execute the program via machine controls, such as numerical control (NC), computer numerical control (CNC), or direct numerical control (DNC). These systems are suitable for applications requiring high precision and responsiveness, such as aerospace and defense, automotive, and manufacturing automation.

Electro-hydraulic systems have numerous advantages, including high power density, low maintenance, and long service life. They can operate under extreme conditions, such as high temperatures, pressure, and corrosive environments, making them ideal for challenging applications. Additionally, they offer precise control and can be easily integrated into existing systems.

Examples in Different Industries


One example of electro-hydraulic system application is in the aerospace industry, where these systems are used in aircraft landing gears and flight control systems. Electro-hydraulic systems’ high precision and responsiveness ensure the safe and reliable operation of critical components in these applications.



In the construction industry, electro-hydraulic systems are used in heavy machinery, such as excavators, bulldozers, and cranes. These systems provide precise control and enable operators to perform complex tasks efficiently and safely.



The manufacturing industry uses electro-hydraulic systems in automated assembly lines, robotic arms, and packaging machinery. These systems offer high-speed and high-precision control, increasing productivity and reducing production costs.

Electro-hydraulic systems offer a reliable and versatile solution for various industries that require precise control and high performance. With their numerous advantages and applications, these systems continue to play a vital role in the advancement of modern technology.

If you are looking to replace or retrofit a Hydraulic Power Unit, you need to understand the key components that have made modern HPUs smaller, quieter, and more efficient.

Gone are the days of being limited to just a fixed-speed Hydraulic Power Unit.  In fact, the new variable-speed HPUs are far more energy efficient, and they are starting to dominate the market. Add in the fact that these new units include built-in sensors, diagnostics, and even cloud capabilities, making them very easy to connect to an IoT (Internet of Things) environment, and it’s fairly easy to see why they have become so popular.  The sheer amount of predictive maintenance data alone makes the investment worth it!

The most important part of replacing a Hydraulic Power Unit is understanding how the modern hydraulic system design differs from the older conventional systems in aspects like size, noise, energy efficiency, connectivity, and total cost of ownership.  Let’s take a look at those differences…

The Main Differences Between Conventional and Modern Hydraulic Power Units

Hydraulic Power Unit Size

HPU size is often determined by the size of its hydraulic fluid reservoir. For traditional HPUs, the reservoir minimum is normally two to five times the maximum pump flow.

Conversely, modern HPUs can be designed to a 1:1 flow/reservoir size ratio due to pump controls,  advanced manifold design, and the use of variable frequency-driven motors to drive the pumps.  As a result, a unit that produces a max flow of 150 GPM per minute may only need a reservoir capacity of 150 gallons, or 75 percent less reservoir capacity than a traditional HPU.

Hydraulic Power Unit Noise

By operating at variable speeds, modern units are quieter because they don’t demand their full power at all times.  Instead, they are only delivering the power needed at any given time.

Furthermore, modern systems can be built from materials that dampen sound and minimize vibrations by using designs like a liquid-cooled motor, compact arrangement of components, unitary housing, and built-in sound-insulating mats.

Hydraulic Power Unit Energy Efficiency

A fixed-speed HPU operates at 100 percent motor speed at all times. In turn, any energy not being used to do work is converted to heat. This all results in higher energy costs and excess heat production that must be controlled using cooling – which requires even more energy.

Variable-speed systems adjust energy output to match the demands of the operation. As such, variable-speed HPUs have demonstrated energy savings of up to 80 percent. Lower, more controlled operating speeds also reduce the unit’s heat output, allowing it to run cooler and reduce or eliminate the need for additional cooling measures and their associated costs.

Hydraulic Power Unit Connectivity

With a modern HPU, access to cloud-based diagnostics and data analytics tools streamlines workflows and reduces the demand for personnel to capture critical data and troubleshoot equipment in person.

Some HPUs include case drain flow/temperature, particle counter, energy consumption, pump damage, and other monitoring parameters, with real-time access to performance and usage reports 24/7 via dashboards on a mobile device.

Hydraulic Power Unit Total Cost of Ownership

Modern variable-speed HPUs may be more of an investment upfront, but manufacturers with high energy costs driven by fixed-speed HPUs will see more value and a faster return on their investment.


Atlantic Hydraulic Systems has designed, manufactured, and commissioned many key elements in the fight against the rising tides of the world.

We live in a busy society that is dependent on our ability to travel, transact business, gather at social events, and connect with other humans on multiple levels. With each passing day, however, our need to connect is also contributing to adverse effects on our planet.

The Earth’s Temperature Is Slowly Rising And Our Water Levels Are Rising Along With It

Ultimately, the earth is getting warmer and that increase in temperature – however subtle or blatant it may be – is contributing to higher ocean tides and rising water levels on a global scale.

Our oceans absorb over 90% of the excess heat generated by our planet and that is throwing some major complications into the delicate ecosphere. Increases in temperature are adding to the overall water volume on the planet by melting giant ice sheets and glaciers. This, thereby, contributes to sea level rise.

As sea levels rise, there’s an adverse effect on our lands, weather, and the frequency of floods in areas that are otherwise usually free of flood dangers.

To that end, our society is placing ever more emphasis on stormwater management, flood protection, and water control gates to either mitigate damage or outright prevent damage from rising water levels.

Atlantic Hydraulic Systems Is Playing A Major Role In Mitigating And/Or Preventing Unnecessary Damage From Rising Tides

In turn, Atlantic Hydraulic Systems has designed, manufactured, and commissioned many key elements in the fight against the rising tides of the world including Hydraulic Power Units, Hydraulic Control Panels and Hoist Winch Control Panels for water control management systems like Crest Gates, Sluice Gates, and Tainter Gates.

Important aspects in the hydraulic power unit and control system design for Crest, Sluice, and Tainter Gates are:

  • Designing for emergency gate closure and opening in a no-power condition
  • The ability of the gate hydraulics to detect gate blockages while moving to protect the structure
  • Gate position feedback and monitoring
  • Design for no single-point failure event possibility using redundant pumps & controls
  • Ability to control operation locally or via a SCADA system – which is a control system architecture for high-level supervision of machines and processes.


Our Recent Projects To Help Combat The Effects Of Floodwater and Rising Tides

Atlantic Hydraulic Systems designed, manufactured and commissioned the floodgate hydraulics and control systems at Seabrook Gates in New Orleans. Atlantic’s on-site technicians directed the installation of the HPU, hydraulic cylinders, hydraulic plumbing, and both high voltage and control wiring.

The gates are controlled using a user-friendly graphic interface and provide closed-loop position control of the gates and safety interlocks with the gates locking mechanisms.

We even designed, manufactured, and installed the hydraulic system for the Orleans Avenue Gates in New Orleans, LA after Hurricane Katrina. Five hydraulically driven winches were placed to lift and lower massive gates to prevent water flow in the canal during a storm. The HPU is designed to communicate with the municipal SCADA systems as well as to be run manually.

Most Recently, after Hurricane Sandy, we were commissioned to design and manufacture both the temporary and permanent hydraulic systems during the Metropolitan Ave Bridge machinery replacement in New York, NY. Now, two of our 60 HP hydraulic power units and four 10″ bore x 96″ stroke cylinders drive the two massive leaves of the bridge in addition to four of our 7.5 HP hydraulic power units which drive the tail locks into place.

We at Atlantic Hydraulic Systems may not be able to control the earth’s temperature – but we are certainly at the forefront of how we can prevent or mitigate any damage of the rising tides or flooding that may be happening as a result.