Schoolhill Hydraulic Engineering has been designing and manufacturing hydraulic equipment from its Aberdeen-based factory since 1952. Schoolhill specialises in the design of all types of hydraulic cylinders, and also has extensive experience in the design of hydraulic flow control valves and directional valves. We were one of the first hydraulic cylinder manufacturers in Scotland to achieve ISO9000 quality assurance accreditation.
Hydraulic cylinders
Schoolhill specialises in the design of all types of hydraulic cylinders up to 24in (600mm) bore x 2M stroke, and 10in (250mm) bore x 8M stroke. This includes multi-stage single and double-acting cylinders, hollow rod cylinders, and double-ended types. For heavy-duty applications Schoolhill cylinders will accept around 50% more side-loading than other manufacturers’ products.
Development of a wide range of hydraulic-powered equipment over the past 30 years has provided an invaluable proving ground for the reliability of our own cylinders. Over 1 million cycles a year are achieved by some of our mechanical handling machinery.
Hydraulic cylinders for harsh environments
Hydraulic cylinders are Schoolhill’s primary product. With over 30 years’ experience design hydraulic cylinders for harsh environments and deepwater operations, our expertise is second to none.
Tiebolt cylinders are often preferred for oilfield completions, wellhead connectors and running tools. They are also popular within the machine tool industry. Construction equipment and many process control systems favour welded construction cylinders, usually conforming to ISO standards. A third type, often described as mill cylinders, have a threaded or cap-screwed body; these are used in the iron and steel industry.
Heavy-duty tiebolt cylinders and subsea cylinders
A range of heavy-duty tiebolt cylinders has been developed specifically for subsea wellheads and running tools. These have some unique design features not available from any other hydraulic cylinder manufacturer.
Schoolhill also manufactures subsea cylinders for use in water depths to 12,500ft. Due to the high cost of recovery, component failures in oilfield subsea applications cannot be tolerated. Cylinders can be flushed clean after assembly, but many people do not appreciate that it is their design that provides the ability to maintain that cleanliness throughout their working life. Schoolhill cylinders designed for long-term subsea applications are capable of sustained cleanliness at better than NAS6.
Piston and gland seals
Double seals to packing glands can usually be accommodated within original cylinder dimensions, which means that extended housings are not necessary – a benefit that many other manufacturers do not provide. Schoolhill piston and gland seals can be arranged to provide a secondary backup in a critical direction. Years of experience in testing various types of seals have allowed Schoolhill to move significantly ahead of the competition.
Pipe handling systems
Schoolhill designs and manufactures pipe handling systems to solve many types of tubular transportation problems. Several different types of standard units are available and may be included as an integral part of any tubular handling system.
For pipe cleaning we manufacture lance feed units, containment muffs, axial rotation drive units and over arm safety clamps. For premier threading we manufacture:
- Idler roller jacks
- Powered drive roller jacks
- Kick off arms
- Stop and single release units
- Hydraulic chocks
- Lathe steadies
- Powered turntables
- Dipping tables
- Pipe racks
Stainless-steel valves for oilfield control systems
Schoolhill manufactures stainless-steel valves for oilfield control systems, both topside and subsea. This product range was born out of a customer need for specialist valves, mainly for use in ESD systems, designed particularly to meet harsh oilfield conditions. These valves have a high degree of reliability and are suitable for use with BOP fluids and water glycol solutions.
Our valve range includes:
- Quick dump valves
- PO check valves
- Fine metering valves
- Pressure-operated shuttle valves
- PO directional control valves
Wellhead tools
Schoolhill can design and manufacture any type of special running tools to suit your requirements. Our current range of wellhead tools includes:
- Patented gripper cylinders
- Valve override tools
- BOP orientation pin cylinders
- Sleeve pulling tools
- Tools for automatic release
Schoolhill has developed a range of hydraulically powered orientation pins where the pin itself forms an integral part of a hydraulic cylinder, built into various types of API flange. When the API flange is bolted into place on the BOP body, hydraulic lines are connected through the flange to the hydraulic cylinder, which inserts or removes the orientation pin remotely.