Hydraulic Cylinders

About Hydraulic Cylinders and Hydraulic Cylinder Distributors Including: Double Acting Hydraulic Cylinders, Heavy Duty Hydraulic Cylinders, High Pressure Hydraulic Cylinders, Hydraulic Pistons, Hydraulic Rams, Hydrolic Cylinders, Replacement Cylinders, Small Hydraulic Cylinders, Stainless Steel Hydraulic Cylinders, Telescopic Cylinders, Tie Rod Hydraulic Cylinders & Welded Hydraulic Cylinders.

Hydraulic cylinders are linear hydraulic motors that turn the hydrostatic power of a fluid into mechanical power. Typically, the hydraulic fluids utilized in the cylinder are oil, most commonly used in industrial applications, and water. Hydraulic cylinders consist of a plunger or piston inside a cylindrical housing. The bore of the cylinder must be perfectly cylindrical to prevent any obstruction of the piston. Piston seals prevent internal leakage from the high pressure side of the hydraulic cylinder to the low side. Rod seals are used to prevent external leakage. Piston rods, which move in and out of the hydraulic cylinder, are usually hard chrome plated to provide protection from corrosion and wear resistance. Hydraulic cylinder distributors most often offer their products in steel, stainless steel or aluminum.

Hydraulic cylinder distributors can supply single action hydraulic cylinders or double action hydraulic cylinders. A single-acting hydraulic cylinder is configured for motion in only one direction, either pulling in or pushing out. An internal spring is used to provide plunger return when the hydraulic pressure is removed. In single-action hydraulic cylinders, less valving and plumbing is needed than in double-acting hydraulic cylinders. The more complex double-acting hydraulic cylinder is pressurized to move in both directions along the vertical or horizontal plane, or any other plane needed. These custom hydraulic cylinders provide higher speed operations and tighter control than single-acting hydraulic cylinders, and are less sensitive to system back pressures that can occur due to long tube lengths in telescopic cylinders.

Telescopic cylinders have strokes that extend far beyond that of a standard hydraulic cylinder. Telescopic cylinders are multi-stage hydraulic cylinders that are ideal for applications in which there are severe space limitations. Telescopic double-acting hydraulic cylinders are highly complicated, as they actually consist of three or four concentric tubular components. These custom hydraulic cylinders and components need to be manufactured to a high degree of precision and accurately put into position with precise clearances. The outer piston must have all the characteristics of a hydraulic cylinder body from the inside and all the features of the piston rod on the outside. Special provisions are made to allow the passage of fluid up to the inner hydraulic cylinders. Telescopic cylinders are used in a variety of industries, such as agriculture, construction and machinery manufacturing.

Hydraulic cylinders are often used as part of a larger hydraulic system that includes pumps, valves and motors. Hydraulics can be effectively combined with other technologies through the use of sensors, transducers and microprocessors. Hydraulic cylinder distributors work with many industrial equipment applications, including bulldozers, aerial lifts, weapon systems, drilling rigs, forklift trucks, farming and demolition equipment, etc. When ordering hydraulic cylinders, it is important to know the bore, stroke and rod sizes, the retracted pin center, the pressure requirements for the extending and retracting of the piston rod and the flow rate of the hydraulic fluid. Other necessary pieces of information concerning hydraulic cylinders include rod material, operating temperature range and coating.

Hydraulic Cylinders and Hydraulic Cylinder Distributors Image Provided by Cylinders & Valves, Inc.

Hydraulic Cylinders and Hydraulic Cylinder Distributors Image Provided by Lynair, Inc.

Types of Hydraulic Cylinders

• Double-acting cylinders use hydraulic pressure to actuate the rod to extend and retract in both directions.
  
• Heavy duty cylinders are designed for high pressures, high flows and rugged environments. Heavy duty cylinders are particularly suited to demanding industrial and mobile applications.
  
• High pressure hydraulic cylinders have significantly smaller and lighter designs than standard cylinders, which saves substantial weight and space in equipment. High pressure hydraulic cylinders are used in applications that need high forces and short or medium strokes, such as material testing and material transforming.
  
• Hydraulic cylinder manufacturers make the appartus that changes hydraulic fluid into mechanical power.
• Hydraulic cylinders use hydraulic fluid to make mechanical power.
• Hydraulic rams are the large output pistons.
• Large bore cylinders are designed for a multitude of applications in which a large force is required in both the push and pull directions.
  
• Mobile hydraulic cylinders are used in many applications, such as snowplows, construction equipment, personnel lifts and material handling equipment.
  
• Single-acting cylinders use hydraulic pressure to actuate the rod in only one direction.
  
• Small hydraulic cylinders can have strokes of less than an inch and are used in applications that require extreme precision.
• Stepped cylinders are two-way hydraulic cylinders that provide a faster starting stroke and a subsequent, more powerful working stroke.
  
• Telescopic cylinders have multiple stages which enable longer strokes to be achieved, while utilizing less space.
  
• Thread cap cylinders have their head gland threaded on and the threads are protected by an o-ring.
  
• Tie-rod cylinders use one or more tie-rods, which are installed on the outside diameter of the cylinder housing, to provide extra stability. Cylinder tie-rods commonly bear a large portion of the applied load.
  
• Welded cylinders are made of a heavy duty, smooth welded housing for increased stability. Most housings of hydraulic cylinders are made of multiple parts, but not in the case of welded cylinders.

Common Terms Related to Hydraulic Cylinders

Accumulator - A container in which fluid is stored under pressure. Accumulators have some type of limit in the loading mechanism for maintaining pressure.

Bleeder - Also called a bleed valve, or a device commonly used on hydraulic cylinders to remove pressurized fluid and air from the system.

Bore - The inside diameter of hydraulic cylinders.

Cap - End closures of hydraulic cylinders, that completely covers the bore area.

Closure - Cap, plug or cover for the fluid passage of hydraulic cylinders.

Depth Control Cylinder - An adjustable, mechanical or hydraulic device that is used to limit the stroke of hydraulic cylinders.

Flow Control - A device which meters the rate of fluid used in hydraulic cylinders.

Gland - The cavity of a stuffing box used within hydraulic cylinders.

Head - The end closure of hydraulic cylinders that covers the differential area between the bore area and the piston rod area.

O-Ring - A type of seal consisting of an elastomer in the shape of a doughnut. O-rings are usually mounted in a groove on hydraulic cylinders for sealant purposes.

Piston - A cylindrical member forming the internal element of assemblies in hydraulic cylinders that transmits or receives motion by a connecting rod. Fluid acts with the piston to convert pressure energy into linear motion within hydraulic cylinders.

Psi (Pounds Per Square Inch) - A unit of measurement of pressure within hydraulic cylinders.

Pump - A device found within hydraulic cylinders that turns mechanical energy into either fixed or variable hydraulic energy.

Ram - The large output piston of a hydraulic cylinders press.

Regenerative Circuit - A device that directs the rod end discharge to the piston side of hydraulic cylinders, increasing the speed of hydraulic cylinders. Regenerative circuits can be incorporated into a directional control valve as the fourth position on hydraulic cylinders.

Rephasing Cylinder - A design that allows the use of two or more hydraulic cylinders in a series. This design automatically synchronizes the position of hydraulic cylinders at the end of every stroke within the hydraulic cylinders.

Rod - A device that connects the bore area to the head of hydraulic cylinders.

Spool - Any cylindrical-shaped part of hydraulic cylinder components that controls the flow passing through the component in accordance with its movement.

Stroke - The linear movement of a valve spool or hydraulic cylinder rod that establishes the limits of motion.

Stuffing Box - A small chamber in found within hydraulic cylinders that is compressed around a reciprocating shaft or piston to form a seal.