Refrigeration

Refrigeration circuits are basically comprised of four components: a compressor, a condenser, an expansion valve and an evaporator.

The gaseous refrigerant, e.g. ammonia, is highly compressed in the compressor, to enable it to be supplied to the condenser at a high temperature and pressure; the condensed fluid is subsequently fed to the expansion valve in a liquid state at high pressure.

The purpose of the expansion valve is to allow the liquid refrigerant to expand in a controlled way by reducing the high pressure in the compressor to the low pressure in the evaporator; the refrigerant in the evaporator can then remove heat from the space to be cooled and thus chill it.

Industrial expansion valves must satisfy a whole set of requirements. Very high differential pressures have a significant impact on the chiller (for example, if they result in a two-phase flow system with a high flow velocity) and hence on the valve's mechanical properties.

ARI-Armaturen offers bespoke solutions for the control valve required here:

• Different plug types depending on requirements (e.g. V-port plug)
• Rugged, almost vibration-free stem guide
• Stellited sealing surfaces
• Replaceable (reducible) seats (Kvs values), bolted
• Extended bellows (compliant with German clean air regulations)
• Non-ferrous metal free version
• Low-temperature version (min. -60°C)      

In addition to the expansion valve, ARI can also supply all other valve types such as isolation devices or control valves, both for the refrigeration circuit and for the oil circuit of the compressor.

The ARI portfolio comprises products made from SG iron, cast steel and stainless steel with nominal pressures from PN 16 to PN 40 and nominal diameters from DN 15 to DN 500.