Offshore Hydraulic Cylinder Manufacturer

All hydraulic cylinders undergo salt spray testing before delivery.
MOQ starts from 1 piece and the lead time is 15-20 days
We can customize based on your drawings and working conditions, and provide quotations and technical support.

Brands We Serve in Hydraulic Industry

Offshore Hydraulic Cylinders

Offshore hydraulic cylinders are designed for offshore vessels and sub-sea equipment. It can provide power for equipment to push, pull, lift, open and close under salt spray and seawater conditions. They are widely used in offshore oil and gas, offshore wind, subsea engineering and other industries.

The cylinder barrel is made of 2507 duplex stainless steel. It is twice as strong as regular 316L stainless steel and withstand seawater pressure up to 60 M Pa, this can avoid deformation in deep water. We choose seals based on pressure , for deep-sea high pressure,we use hydrolysis-resistant polyurethane. It has a tensile strength of 40–50 MPa and strong extrusion resistance, so it won’t get squeezed out under high pressure.

Using an external anti-corrosion process. We perform Sa2.5 grade sandblasting on the surfaces of the cylinder barrel, cylinder head and other parts to improve resistance to offshore salt spray corrosion. We can customize products according to your drawings and working conditions.

Your Reliable Supplier of Offshore Hydraulic Cylinders

We have years of experience making offshore hydraulic cylinders, supply cylinders for offshore equipment such as drilling platforms, deck machinery and cranes. We know these machines have to deal with seawater and salt spray corrosion at sea, so we give the cylinder parts special treatment. For example, the piston rod uses 17-4PH precipitation hardening stainless steel. We hard-chrome plate its surface; the coating reaches HV800–1000 in hardness, this help resist seawater corrosion better.

We can customize production based on your drawings and equipment model. We also provide technical review to provide you qualified hydraulic cylinders.

offshore Hydraulic Cylinder

Applications of offshore Hydraulic Cylinder

Sub-sea Valve Push/Pull

Marine hydraulic cylinders are used in sub-sea valve, through extend and retract a piston rod that connected to the valve stem, let the gate move up and down to open or close the valve. The cylinder can deliver high thrust to withstand spring force and pipeline media pressure, so the valve opens and closes smoothly.

BOP Ram Movement

Marine hydraulic cylinders are used in BOP ram actuators. Two cylinders are mounted on both sides of the BOP. Hydraulic oil pushes the pistons out, moving the two rams toward the wellhead at the same time. This can close the wellhead and stops high-pressure oil and gas from rushing up. The cylinders are equipped with accumulators to store high-pressure oil in advance. So even when the system stop, they can still close the well and avoid the risk of a blowout.

Deck Crane Luffing

Offshore hydraulic cylinders are used in the luffing system of deck cranes. The two ends of the cylinder are pinned to the boom and the turntable. When the cylinder extends and retracts to change length, it swings the boom up or down. The piston rod is made of 17-4PH and hard chrome plated. It can pass a 240-hour neutral salt spray test, it can better resist seawater corrosion offshore.

Wellhead Safety Valve Reset

Offshore hydraulic cylinders are used in safety valve reset systems. The cylinder is mounted above the safety valve. Its piston rod extends and pushes the valve stem, bringing the safety valve back to the open position. The cylinder has a pilot operated check valve inside, this allows the system to supply oil remotely to reset the valve stem. So it don’t need to go on site and do it by hand, improving safety for offshore work.

Jack-up Leg Raising and Lowering

Offshore hydraulic cylinders are used in leg lifting equipment. The cylinders work with upper and lower grippers to lock the leg in turns. Through the cylinder extends and retracts to jack the platform up step by step. The cylinder uses a thickened high-strength barrel with wall thickness ≥35 mm. It can bear the heavy load when lifting or lowering the platform.

Lock Gate Swinging

Offshore hydraulic cylinders are used in ship lock gate swing. The two ends of the cylinder are hinged to the gate and the lock wall, through the piston rod extends and retracts to swing the gate around its hinge point for opening or closing. The cylinder uses a combination of wiper and main seal, it can let sand and floating debris out to protect piston rod. This helps the gate work steadily from long time.

Deep water pressure causes barrel deformation

When working underwater, seawater creates high external pressure. The hydraulic cylinder must withstand this high outside pressure, while the internal oil pressure is often low. This creates a large pressure difference between inside and outside. If we only design the cylinder for internal pressure, this pressure difference may squeeze the barrel out of shape and bend the piston. The cylinder may jam or lose pushing, and affects equipment works.

Before production, we will do an external pressure buckling analysis, according to key data like actual seawater depth and cylinder dimensions, to simulate and test whether the cylinder will deform under this pressure difference. If we find weak areas, we thicken the barrel in advance, this helps it resist outside water pressure better and ensures the cylinder works reliably in deep water.

Seawater gets in and breaks the hydraulic system

Long-term friction and seawater corrosion will create tiny gaps in the seals, then the seawater enter the cylinder through these gaps. As seawater enter, it will mixes with the hydraulic oil. This makes the oil break down and creates particles that clog valves and lines. In serious cases, it can cause the hydraulic system fail.

Our solution is use a main and secondary dual sealing system. The main seal stops most seawater from getting in. If seawater and sand scratch the main seal and a small amount of seawater passes through, the secondary seal will block it. This keeps seawater out of the cylinder, protects the hydraulic oil and parts. We also add a wiper ring to prevent sand damage the seal.

Spring cannot keep its reset ability for long.

Springs need to work in seawater or wet conditions for a long time, and it will corrode. Corrosion creates pits on the steel surface and reduce the effective cross-section. This makes the spring softer and loses force. Specifically, when the spring has to push the valve closed, but the return force is too weak, so the valve cannot close. Seawater then seeps into the cylinder through the gaps, making the cylinder can’t work properly.

For harsh offshore corrosion, we focus on choosing the right spring material. The spring is made of Inconel alloy. This material has very strong corrosion resistance. Its corrosion rate is under 0.002 mm per year, and it has more than 10 times the pitting resistance of ordinary stainless steel. We also add anti-corrosion coating on springs to create double protection. This gives better protection against seawater corrosion, avoids pitting and spring force loss, to ensure reliable spring reset.

Certifications

REACH Certificate

ISO 9001 Certificate

ISO 14001 Certificate

Certificate of Conformity

Why Work with Us

Anti-Corrosion and Sealing Solutions

Using duplex stainless steel with solution heat treatment to improve the corrosion resistance and make the equipment can stable work .

Deep water External Pressure Design

We will do special structural optimization and use seamless steel tubes to thicken the cylinder barrel, so it will not deform under deep water pressure.

Testing Assurance

We do offshore simulation tests on hydraulic cylinders to check pressure resistance, sealing and other performances, ensuring reliable operation under deep-sea conditions