orificioputkilla

Orificioputkilla is the Finnish term used to describe orifice tubes, a type of fixed metering device in refrigeration and air conditioning systems. The device consists of a small-diameter tube with a calibrated orifice that meters the flow of refrigerant into the evaporator. Placed in the liquid line before the evaporator, orifice tubes create a pressure drop as refrigerant passes through the restricted opening, causing part of the liquid to flash into vapor. This metering action regulates the amount of refrigerant entering the evaporator in response to system load, helping to maintain the desired evaporating pressure and temperature.

Construction and operation: Orifice tubes are typically made from brass or similar materials and may include a screen or filter at the inlet to trap debris. They are a fixed, non-adjustable device; the flow rate is determined by the orifice size and the pressure difference across it. In operation, high-pressure liquid refrigerant enters the tube, expands and partially vaporizes as it exits into the low-pressure evaporator.

Applications and advantages: Orifice tubes are commonly used in automotive air conditioning and some residential/commercial systems, especially where a simple, low-cost metering solution is suitable. They have few moving parts and are relatively robust.

Limitations: Performance can vary with duty cycle and ambient conditions, and clogging from contaminants or moisture can reduce cooling efficiency. Maintenance may involve replacing the tube and associated components (such as the filter-drier) and ensuring proper system filtration.

See also: Capillary tube, Thermostatic expansion valve, Refrigeration metering devices.