Share article:

Industrial gas compression springs – Design, advantages and uses

Gas compression springs support moving parts or compensate weight. They are used, for example, for doors, hatches or swivel arms. Especially in mechanical engineering and plant engineering, it can be useful for safety reasons to provide certain components and machines with hatches. Gas springs support opening and closing these, especially on heavy hatches and doors. This blog article explains how they work, what variants there are and where else they can be used.

Gas compression springs and gas tension springs

The term gas spring, or industrial gas spring, is used as a generic term for gas tension springs and gas compression springs. Gas compression springs consist of a cylinder, a piston and a piston rod. The piston connected to the piston rod is movable. The cylinder forms the frame of the gas compression spring. Depending on the type, there can be different adapters for connecting to other components, e.g. threaded pins, angle joints or clevises. The gas pressure is preset using a valve.

Generic gas compression springs store the energy supplied to them when the piston rod is pushed in by compressing the gas in the cylinder, e.g. nitrogen gas. The gas compressed by the volume change aims to regain its original volume and thus generates a return force, which pushes back the piston and thus the piston rod. When gas compression springs are at rest, the piston with piston rod is fully extended.

Gas compression dampers are a special type of gas compression spring. In addition to supporting movement, a damping function is installed by means of a back pressure opening, i.e. they regulate the speed of the closing movement by internal pressure compensation, thus simultaneously damping shocks. Depending on the design, oil can also be used to regulate the push-in speed. The non-compressible oil is routed through the back pressure opening, which limits the flow rate of the oil between the chambers separated by the piston. In combination with an additional gas-filled chamber, a damping effect and a limited speed of movement of the piston in the cylinder can be achieved.

  • Left gas compression spring (1) = can only be mounted up to a maximum slope of 60°
  • Right gas compression spring (2) = any mounting direction
  • 1 = Mounting part
  • 2 = Cylinder Housing
  • 3 = Piston
  • 4 = Piston rod
  • 5 = Back pressure opening
  • 6 = Seal
  • 7 = Rod guide
  • 8 = Oil
  • 9 = Free piston
  • 10 = Gas filling (compression)
  • A = Chamber A
  • B = Chamber B
  • C = Chamber C

Gas tension springs are constructed similarly to gas compression springs. In these cases, however, the piston rod is in the interior of the cylinder, initially in an unloaded position. When the piston rod is placed under tensile load and the piston is pulled outward, the gas, e.g. nitrogen, in the chambers (A and B) is compressed. The compressed gas attempts to regain its original volume and pushes the piston back into its original position.

  • 1 = Mounting part
  • 2 = Cylinder Housing
  • 3 = Seal
  • 4 = Piston
  • 5 = Back pressure opening
  • 6 = Vent Hole
  • 7 = Rod guide
  • A = Chamber A (gas filled)
  • B = Chamber B (gas filled)

Design of gas compression springs

Important parameters for calculating gas compression springs are their mounting points. They directly affect function. Gas compression springs only fulfill their purpose when placed and dimensioned correctly. The closed hatch serves as the starting point for the calculation.

For hatches, the required deployment force of the gas compression spring can for example be calculated as follows:

F = \frac {W \times A}{B \times n} \times 1.1
  • W = Weight of doors, etc. in kg
  • A = Horizontal distance between the hinge and the center of gravity (the point at which the entire hatch weight comes to bear)
  • B = Vertical distance between the hinge and the mounting point of the gas compression spring
  • n = Number of gas compression springs to be used
  • F = Required push-out force (at max. length)
  • 1 = Door
  • 2= Axis line

Advantages of gas compression springs

Gas compression springs have several advantages over conventional compression springs:

  • Precise motion control: Precise motion control is possible thanks to adjustable damping. There are no abrupt stops or undesirable vibrations. The force can also be precisely adjusted.
  • Durability and reliability: Gas compression springs are fully sealed, which is why they are less susceptible to wear and external influences.
  • Easy installation and maintenance: Gas springs are low-maintenance because they do not require additional lubrication
  • High and almost constant force: Despite the rather compact housing, gas compression springs can generate considerable forces that remain almost constant over the entire stroke. Gas compression springs with damping have a kinked force curve in the region where the damping effect is initiated.

Various variants of gas compression springs

There are different types of gas compression springs for a range of applications:

  • Locking gas compression springs: Locking gas compression springs can be locked in various positions.
  • Gas compression springs with ball head: Gas compression springs with ball head have a ball head at the end of the piston rod. This allows the gas compression spring to be integrated in a flexible and movable manner.
  • Gas compression springs for lids: Gas compression springs for lids facilitate opening, holding and closing lids in a controlled manner.
  • Gas compression springs with floating piston: Gas compression springs with floating piston have a special construction with two cylinders. The floating piston separates gas and oil from each other.
  • Progressive and degressive gas compression springs: Due to their non-linear deployment force, progressive or degressive gas compression springs are used on very heavy doors or hatches. Depending on the design, they provide greater support at the start of the stroke or the end of the stroke.

Gas compression springs from MISUMI

MISUMI offers a variety of different industrial gas springs. This includes compact gas compression springs for space-saving applications, gas compression springs that enable high initial loads and a wide range of stroke lengths.

The following table provides an overview of the available gas springs and their possible applications:

Properties of gas springs
Catalog Name Properties Preload— N [D] Outer Diameter Stroke - S
min. max. min. max. min. max.
GSP Compact and highly resilient.
A larger selection of sizes for more freedom.		 1500 30000 19 63 10 80
GSQ A heavy-duty type of GSP32 (starting load capability is 32% higher than GSP32.) 6600 6600 32 32 10 80
GSN Lower height, ideal for high load capacity. 3750 20000 32 63 10 100
MGSN Entry-level class with a smaller diameter, which ensures that it also fits in compact molds. 1000 5100 16 32 10 80
MGSL Ideal for applications with a slightly higher load than with helical springs. 800 1600 19 25 10 80
MGSM Screw-proof type 400 800 12 16 10 25
GSX Classic gas spring 4750 31000 32 63 10 80
GSV Large selection of approximately 150 sizes. The most commonly used model. 1700 117000 19 195 7 125
GST Diameter, length and load as with GSV. The depth of the setting hole is lower than with GSV. 3600 95400 32 150 10 125
GSH Diameter, length and load as with GSV / GST, the shape of the lower groove and the mounting distance are different 9200 66300 50 120 10 125
GSK Initial force up to a maximum of 106.000 N and maximum stroke length up to 300 mm. 1700 106000 32 195 10 300
GSSC Initial load up to a maximum of 184.100 N, the attached plastic cap prevents contamination 4250 184100 25 150 6 50
HSE Minimum diameter Ø 12, the smallest model 50 3200 12 32 7 125

MISUMI also supplies gas springs with integrated safety devices:

  • OSAS: active overstroke protection
  • USAS: active protection on uncontrolled return stroke
  • OPAS: active overpressure safety device

OSAS ensures that the internal nitrogen gas is released during an overtravel and thus prevents the gas spring from deforming. USAS prevents the internal components of the gas spring from breaking and the piston rod from being propelled outward when the movement of the piston rod becomes uncontrollable. OPAS is an active safeguard against overloading by overpressure. If machine oil or other substance penetrates the gas spring and cause an abnormal pressure increase, OPAS releases the internal nitrogen gas and thus prevents deformation and/or failure of the gas spring.

Uses of gas compression springs

In addition to many other applications, gas springs can also be used for safety devices. In an emergency, they can for example be used to open emergency exit doors or emergency hatches quickly and in a controlled manner. Gas compression springs can assist when positioning and securing workpieces during assembly or with testing devices.

Gas compression springs can also be installed directly in a composite system, for example, with a pressure control display. This enables precise control of the spring force and increases safety. MISUMI offers all the components required for this purpose.

The following sequence is recommended when selecting the individual components:

Such a composite system can be constructed as follows, for example:

  • 1 = Gas compression spring
  • 2 to 4 = Adapter
  • 5 = Fabric hose
  • 6 = Clamp for connecting
  • 7 = Pressure control unit

Installation and safety instructions

Industrial gas compression and gas tension springs are only approved for industrial use and are not approved for installation in motor vehicles. Incorrect installation, use in damp environments or outdoors, and modification of the gas pressure or the cylinder can lead to malfunction and serious accidents, including explosions. Gas compression springs are delivered with a preset pressure and are intended for use with this preset pressure. This pressure must not be changed. Defective gas compression springs must be replaced immediately. Wear safety goggles when removing and replacing the unit. The compression spring should be depressurized before disposal. For safety reasons, the compressed gas should first be released from the spring.

Gas springs contain high-pressure gas. It is therefore particularly important to observe certain rules when using and installing them. They must therefore never be modified, heated in any form (e.g. by welding, melting) or disassembled. The ambient temperature is also a decisive factor for safe use. Gas springs that are heated to 80°C can explode or the internally installed seals can be damaged, which leads to gas leakage and loss of function. A convection distance of approximately 2 mm is recommended on each side of the spring to dissipate heat. Avoid contact with the mounting holes.

Frequent errors that can lead to damage or gas leakage:

  • An oblique load or a transverse load is exerted.
  • The gas spring is not fastened with bolts.
  • The pressure on the piston rod is not exerted over the entire surface.
  • The contact surface of the piston rod is deformed.
  • A large amount of lubricant (especially chlorine-based lubricants) was applied.
  • The gas spring came into contact with moisture, steam or chemicals.
  • The gas was refilled or the pressure was adjusted.
  • The cylinder was ground off.
  • The gas spring is used or stored outdoors or in a damp place.