Hansen gas powered valves are available in different variants and have been developed to control the flow in suction lines, wet return lines in pumping systems and systems with natural circulation, in systems with hot gas defrosting especially at low temperature. The valves are normally opened by the spring and do not need a pressure to stay open. A solenoid valve in the discharge line is required for the valve to close. These valves can be installed in both horizontal and vertical lines and are best placed on their sides for a better flow of fluid and oil. They are suitable for NH3, R404a/R507, R134a and other synthetic refrigerants.
Operation:
Pressure gas actuated valves are normally kept open by a spring. When a high pressure gas is introduced to the valve through the pilot line inlet, the combination piston/seat is forced down, compressing the spring and seating the piston/seat firmly on the valve body taper seat. To re-open, the high pressure gas has to be interrupted and the remaining high pressure is bled-off past the bleed in the piston/seat to the outlet of the valve (HCK2 and HCK5D) or through an external degassing (HS9B). The pressure at the inlet together with the spring ensures that the valve is fully open.
Available models:
The HCK2 is the simplest version of the gas powered valves. To close the valve with hot gas, the solenoid valve has to be powered. While the HCK2 valve is closed, some gas will always flow along the piston to the outlet of the valve. It is therefore recommended that these valves are only used for short-term closure, for example during defrosting, or when bleed to suction is not objectionable.
To reopen only the solenoid valve has to be closed.
Features:
If it is not allowed that gas will bleed along the piston to the outlet during closing, the HS9B must be used. The piston of this valve has piston rings that will prevent that a bypass of high pressure gas is created. To close the valve with hot gas the hot gas inlet solenoid valve has to be powered. To reopen the inlet solenoid valve is closed and the outlet hot gas solenoid is powered to discharge the remaining hot gas.
Features:
The HCK5D is a two-stage valve. The HCK5D has an internal controlled bleed-down (equalize) feature which will allow the main seat to open until the pressure across the valve is at a lower, safer pressure level. This eliminates the need for a separate bleed-down solenoid valve assembly which greatly simplifies the piping and reducing installation costs.
Features:
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