Question 182Refrigeration/AC - Assistant Engineer70% to pass
Which of the following illustrated expansion valves is designed to maintain a constant evaporator pressure rather than a constant evaporator superheat? Illustration GS-RA-24
AI Explanation
The correct answer is C.
The expansion valve designed to maintain a constant evaporator pressure rather than a constant evaporator superheat is the thermostatic expansion valve (Type C in the illustration). This type of valve monitors the evaporator pressure and adjusts the refrigerant flow to maintain a specific evaporator pressure, which helps control the cooling capacity of the system.
The other types of expansion valves, A, B, and D, are designed to maintain a constant evaporator superheat, which is the difference between the evaporator outlet temperature and the evaporator saturation temperature. These valves are used when it is more important to control the superheat rather than the evaporator pressure.
Related Questions
#180 The thermostatic expansion valve in a refrigeration system further opens when the diaphragm flexes downward. With all other conditions being the same, what single condition causes this? #181 A typical shipboard domestic multi-box refrigeration system operates with one compressor and condenser. What is the purpose of the sensing line connected to the thermal bulb at the evaporator coil outlet? #183 Besides the evaporator pressure, the thermal expansion valve reacts directly to changes in what parameter? #184 Constant superheat is maintained at the evaporator coil outlet of a refrigeration system or unit by the action of what device? #185 Concerning the proper installation of the sensing bulb of a thermal expansion valve that is attached to the evaporator tail coil on a horizontal run, what statement is true?