4-way reversing valves
Since 1990, Fabris Dott. Ing. Pasquale S.r.l. has developed and manufactured medium and high capacity 4-way reversing valves.
Since 1990 we have operated in the knowledge that the 4-way valve is one of the most important components of heat pump systems.
Our valvesare manufactured with the utmost care and precision because we want to provide our customers with a product of excellence and absolute reliability.
From the 1st to the 13,000th valve manufactured, product development has never stopped, with frequent improvements that are much anticipated and always valued by our customers.
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Fabris 1926 because...
The performance of a 4-way valve
always depends on how it is built!
15 reasons that make Fabris 1926 4-way valves unique in the world
Fabris Dott. Ing. Pasquale S.r.l. began manufacturing 4-way reversing valves at the start of the 1990s. Through its long-standing production of complex mechanical products, the company has rapidly acquired the expertise needed to develop a range of high-performance valves, suitable for the most demanding customers who believe in the high quality of products to constantly conquer new markets.
Our technical department designs both the components and the valve assembly with 3D solid models to maximise the mechanical aspects of construction and minimise pressure losses in the valve crossing.
For these products, as for all those that we manufacture, we use the best materials for all components, with high-precision machining carried out only on technologically advanced systems, special treatments on surfaces subject to sliding, and surface treatments on the external parts. Very tight mechanical tolerances, very low roughness on the surfaces, seals and flanged parts, all for maximum efficiency.
The cast-iron piston, an internal moving part, flow deviator and heart of the exchanger valve, is made with bevelled and jointed surfaces to best accompany the refrigerant gases from the inlet to the outlet of the valve assembly. The pressure loss across the valve is comparable to that of a 90° elbow. The tightness between the piston and the valve body is made possible by the very low roughness and coupling tolerances.
The ground and hardened cast-iron piston has a design geometry that prevents it from stopping at a point intermediate to the two working positions at the stroke end. Depending on the mass of the piston, the minimum pressure difference that enables reversing ranges from 0.8 to 1.0 bar. To avoid or soften the impact of the piston at the stroke end against the head flanges, it is possible to disable operation of the compressor during reversing.
Screw, scroll and magnetic levitation compressors. When there is little, very little or no oil in the circuit, our 4-way vales continue to reverse normally.
External sealing is ensured by suitable O-rings with an extended temperature range (-40°C/+150°C). The O-rings have excellent suitability for all types of refrigerant gases and lubricants, high compressive strength at high temperatures, and good flexibility at low temperatures.
8. Easy installation
All our valves are supplied with 4 unsheathed copper terminals for quick and easy installation. Larger models can also be supplied with steel terminals. We recommend positioning the valve body horizontally. For installation, the valves do not require the prior disassembly of the 2 flanges on the head and the internal piston. It is sufficient to carefully braze or weld the system connection to prevent any residues from entering the valve body that would impede the normal traverse of the ground piston. Before connecting the pilots to the 2 flanges on the heads, it is easy to check the proper traverse of the piston by simply pushing a screwdriver through the threaded holes for piloting, located on the 2 flanges of the heads.
The valve components are checked with coordinate measuring machines in the metrology lab so that they perfectly match the design characteristics.
10. Hydrostatic testing
The valve assemblies regularly undergo rigorous hydrostatic tests at 150 bar that approve their use up to 50 bar at safety level 3. (Download the IMQ test report)
11. Pressure testing
100% of the valve assemblies are pressure tested to check welds, brazes and seals (see photo). The marking on the valve body indicates that the pressure test has been passed.
The highly accurate manufacturing process ensures that the valve assembly – completely maintenance-free – will last well beyond the life of the system on which it is installed.
Problems encountered with these important system components are so rare, our customers can rest assured that we are on hand to deal with any request or need.
14. Stock availability
Our range of 4-way reversing valves is always in stock. From order to delivery in just a few hours, we offer great convenience to our customers!
If our range of 4-way reversing valves does not meet the customer’s specific requirements, we can design and manufacture the special product in a very short time. This is a valuable opportunity for comparison and knowledge building.