When does the suction valve on a reciprocating compressor open?

The suction valve on a reciprocating compressor opens when the vapor pressure in the cylinder is low. This occurs during the suction stroke of the compressor when the piston moves down, creating a pressure drop in the cylinder. As a result of this low pressure, the suction valve is forced open, allowing refrigerant vapor from the evaporator to flow into the cylinder for compression.

Understanding the mechanics of how the suction valve operates is essential for grasping the principles of refrigeration cycles. The valve's opening and closing depend on pressure differentials between the suction line and the cylinder, which is a fundamental aspect of the compressor's function and efficiency. When the pressure in the cylinder is low, it prompts the valve to open to equalize the pressure, facilitating the movement of refrigerant and ensuring the compressor operates effectively.