How it works

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How a fridge works

The temperature in your fridge is controlled by a closed circuit in which a refrigerant flows through condenser coils, an expansion valve, evaporator coils and a compressor.

  1. Condenser coils

    The refrigerant enters the condenser coils as high-pressure hot gas. When it meets the cooler air, heat is released into the room, the refrigerant temperature falls and it becomes a high-pressure liquid.

  2. Expansion valve

    The high-pressure liquid passes through a metered orifice where it changes into a low-pressure liquid. As the pressure drops, so does the temperature of the refrigerant.

  3. Evaporator coils

    As the refrigerant flows through the coils, it absorbs the heat inside the fridge, cooling down the air. Meanwhile, it evaporates into gas.

  4. Compressor

    The compressor constricts the refrigerant gas, raising its pressure and thereby its temperature. It pushes the hot gas into the condenser coils, where the cycle starts all over.
  5. The refrigerant

    Isobutane (R600a) is the most commonly used refrigerant in domestic and small commercial refrigerators.


The compressor is the engine of the refrigeration cycle. Powered by
electricity, a piston works back and forth to suck in the warm low-pressure gas and
push out the hot high-pressure gas.

  1. The valves

    The suction valve bends inward as the gas flows into the compressor and bounces back when the piston is at its right-most position. Similarly, the release valve bends outward as the compressed gas is released and bounces back when the piston is at its left-most position.

Heat resistance

High-efficiency compressors operate at high frequencies and thereby develop heat. The valve steel must have the right properties to handle high temperatures over time.


For the compressor to work, the valve steel must be strong enough to handle both repeated bending motions and impact.

Steel thickness

The thinner the valve steel, the less force is required to bend it. Meanwhile, a thinner valve steel leads to less flow loss at the compressor inlet and exhaust.


Sandvik offers three types of hardened and tempered strip steel for the manufacturing of compressor valves.

Strip steel for the production of compressor valves

Used in

Valve steel is a small but essential part of any compressor and can contribute to both energy efficiency and reduced noise levels in a variety of appliances.

  • Refrigerators and freezers
  • Air-conditioning equipment
  • Brake systems
  • Heat pumps
  • Industrial air compressors
  • Vacuum pumps