Discharge solution for oil-free systems
25th November 2022
DENMARK: The new OFC check and stop valve from Danfoss is said to enhance the reliability and efficiency of systems employing oil-free centrifugal chillers and heat pumps.
The new valve incorporates a damped nozzle check valve, stop valves and diffuser function to address the major application pain points.
The nozzle check valve remains open at minimum flow, closes quickly if there is a system stop generating refrigerant backflow, and, according to Danfoss, improves stability during surge, closing and opening for enhanced compressor reliability.
Decoupled stop and check functions allow fast access and improve reliability of sealing, the company says and the lock ring design prevents unintentional ball valve closures.
The OFC valve has a built-in sight glass and the built-in pressure port connects to a high pressure cut out as an added safety measure.
System efficiency
Minimising pressure losses is seen as critical to ensuring optimum system efficiency. This is even more important at part-load conditions. Danfoss says that optimising the flow path within the valve improves flow capacity and reduces pressure drops by up to 70% compared to using an alternative piston type valve, axial wafer valve or swing wafer.
The Danish manufacturer also emphasises that use of the OFC valve as an all-in-one solution simplifies production planning and spare parts stocking and makes installation faster and easier.
The OFC valve can be set up either vertically, horizontally or at a 45º angle in order to optimise space and minimise piping.
“With the OFC check and stop valve, customers can avoid high pressure drops and unstable performance. Through our innovative approach we have patented the check valve design used in the centrifugal compressor discharge line,” said Danfoss Turbocor director of product management Frank Ford.
Further introductions
Danfoss has also revealed that it intends to introduce a range of dedicated electric expansion valves for oil-free systems.
“We will soon be introducing ETS 175/250/400/500 L electric expansion valves dedicated to oil-free and high temperature applications,” revealed Victor Marinich, Danfoss Air Conditioning’s global segment director. “They are complementing the recent releases within our portfolio of expansion valves and accessories such as the EKF stepper valve driver, the EKE 2U power module, and the brand-new superheat controller platform – EKE 100 – which will be released in 2023.”
