There are two main types of thermal expansion valves: internal or external soaking. The difference between the external and internal balance valves is how the evaporator pressure affects the position of the needle. In the internal balance valve, the evaporator pressure on the diaphragm is the pressure at the evaporator inlet, while in the external balance valve, the evaporator pressure on the diaphragm is the pressure at the evaporator outlet. An externally balanced thermal expansion valve can compensate for any pressure drop through the evaporator.
The internal balance ac expansion valve can be used for single loop evaporator coils with low pressure drop. Multi-circuit evaporators with refrigerant distributors must use external balancing valves. Externally balanced TXV can be used for all applications. However, the externally balanced TXV cannot be replaced with the internally balanced TXV. A type of thermal expansion valve with external balance is called a block valve, which is characterized by an internal sensing ball (usually the metal body of the valve) in the suction pipe joint, especially when the refrigerant For flow control) Nowadays, it often keeps in contact with the refrigerant flowing out of the evaporator outlet, and is often used in automobile evaporators.
Post time: Nov-26-2020