Hot gas defrost is a very common and efficient method of defrosting used within industrial refrigeration, though it does pose a significant safety risk if the injection of hot gas into the evaporators is not carefully controlled.
To minimize this risk, Danfoss has engineered a solution that safely controls hot gas injection: The ICSH Dual Position Solenoid Valve (pictured).
Complying with the latest IIAR safety recommendations for soft gas applications, the ICSH Dual Position Solenoid Valve provides a gradual, time controlled opening for a smooth pressure build-up in the evaporator before it opens the flow to 100% for full defrost.
This two-step approach prevents hydraulic shocks, thereby improving the overall safety of the refrigeration system. Unless the soft opening in step one has been activated, the default ICSH configuration ensures that the full opening in step two does not occur.
The ICSH Dual Position Solenoid Valve opens the flow thorough the main valve in two steps via two EVM-NC solenoid valve pilots. The time delay between the two steps can be controlled either by a PLC, a controller, or a timer.
Once the EVM-NC for step one is energized, the main valve will open for approximately 20% of the main valve full capacity.
After a pre-defined delay, the EVM-NC for step two will be energized and open fully equivalent to 100% of the main valve full capacity.
The ICSH Dual Position Solenoid Valve is based on the ICV platform and shares the same function module as the ICS and the ICV housing. The top cover is also compatible with ICF 50 and ICF 65.