Structure characteristics of 4-Way Reversing Valve in air conditioning system
1 Intermediate Flow By the 4-Way Reversing Valvestructure is not difficult to find, when the main spool valve in the middle position state, as shown in the following figure, E, S, c three take over each other collusion, there is a certain intermediate flow, at this time, the compressor high-pressure tube refrigerant can directly flow back to the low-pressure tube.
The purpose of the design of the intermediate flow is that when the main spool valve in the middle position, can play the role of pressure relief, to avoid the air conditioning system under high pressure damage.
2 The relationship between pressure difference and flow The basic condition of the 4-Way Reversing Valve commutation is the pressure difference at both ends of the piston (i.e. the pressure difference between the exhaust pipe and the suction pipe) (F1-F2) must be greater than the frictional resistance F, otherwise, the 4-Way Reversing Valve will not be reversing.
The minimum operating pressure differential required for commutation is guaranteed by the system flow. When the pressure difference between the left and right piston cavities (F1-F2) is greater than the friction resistance F, the 4-Way Reversing Valve Start, when the main spool valve movement to the middle position, the 4-Way Reversing Valve of E, S, c three cross-conduction, the compressor is discharged from the refrigerant part will be taken from the four-way valve D directly via E, C To form the instantaneous string gas state.
At this time, if the compressor exhaust refrigerant flow is much larger than the 4-Way Reversing Valve intermediate flow loss, high and low dropout will not have a big drop, four-way valve is large enough to the reversing pressure of the main spool valve in place; if the compressor exhaust refrigerant flow is insufficient, because the 4-Way Reversing Valve intermediate flow loss will cause high and low dropout, When the high and low pressure difference is less than the four-way valve reversing the minimum operating pressure difference, the main valve valve will stop in the middle position, forming a series of gas.http://www.shunfengvalve.com/structure-characteristics-of-4-way-reversing-valve-in-air-conditioning-system/4-Way Reversing Valve used in unitary split and window-type heat pump system