TOOLS
in the subcritical and transcritical range and hoses for CO2
includes leak detection equipment, manifolds for CO2
. These products feature special properties.
The leak detector uses NDIR technology to quickly identify changes in CO2
concentration.
NDIR is filtered infrared light with a wavelength at which the gas to be measured absorbs a significant amount of light. A receiver diode measures the incident light; decreasing light intensity indicates a higher concentration of CO2 air. CO2
in the has a characteristic
absorption range that is not overlapped by other gases. There is thus no cross-sensitivity to other interfering gases. The largest source of
interference in leak detection is found elsewhere. In the search for leaks in the refrigeration cycle, interference comes only from the refrigeration
technician’s own breath. The CO2 concentration of air exhaled by humans is 4% – equivalent to 40,000 ppm. If the technician’s exhaled breath reaches the leak detector, a leak is identified and can lead to a false alarm. The manifolds and filling hoses must meet special challenges – the extreme pressures place huge demands on the strength of the components. The equipment must be prevented from bursting under high gas pressure.
Refco manifolds are built with the highest quality materials. The connection block consists of high-grade continuous cast aluminum. The manometers are made of red and blue anodised aluminum. They meet the highest requirements and comply with the latest standards. Due to the precise manufacturing, the tube spring manometers used therein feature accuracy class 1.0. This exceeds the usual precision of manometers for this use. The blowout preventers in the manometers prevent the sight glass from bursting towards the refrigeration technician.
For normal manifolds, Refco uses piston valves. For high pressures, needle valves with a metal sealing surface are used instead. Their advantages are that they have a tighter seal and can be adjusted more precisely. The filling hose must also meet high demands. It requires an inner layer of polyamide that ensures it is leakproof for CO2
. The high pressures are Visit Refco on stand 8-427
absorbed by a wire braid cover, which is in turn protected by an outer layer of abrasion- resistant polyurethane. This cover minimises wear and tear on the filling hoses. Sometimes safety catches are required at the fittings. For greater safety and better handling, Refco uses fittings crimped with the hose that comply with the requirements of DIN EN 857:2016-09. The great demand for such devices justifies the high cost of development.
Safety first
Refco does not use a sight glass because the high pressures permissible in the manifold would result in non-compliance with the safety factors that prevent the sight glass from bursting. As Refco values safety above all, no sight glass is used for CO2
manifolds. Because CO2 is already
present in atmospheric air and the GWP is 1, it might be tempting to forego leak tests in R744 refrigeration systems. However, the tests do not merely detect the emission of the greenhouse gas – more importantly they provide information on the efficiency of the refrigeration system, which is reduced over time if there is a leak. The higher energy demand due to leaks would negatively impact the environment and the electricity bill.
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